Maternal and Child Health

Associations Between Maternity Care Practices and 2-Month Breastfeeding Duration Vary by Race, Ethnicity, and Acculturation Abstract Objectives This study examines the associations between specific maternity care practices and breastfeeding duration for Spanish-speaking Hispanic, English-speaking Hispanic, non-Hispanic Native American, and non-Hispanic White women. Methods We analyzed data from the 2012–2014 New Mexico Pregnancy Risk Assessment Monitoring System. We used survey language as a proxy measure of acculturation and categorized women as Spanish-speaking Hispanic, English-speaking Hispanic, non-Hispanic Native American, and non-Hispanic White. We conducted bivariate analyses to compare rates of breastfeeding at 2 months and experiences of maternity care practices and logistic regression analysis to estimate the effects of these practices on breastfeeding duration for each group. Results Hispanic women were less likely than non-Hispanic women to breastfeed for at least 2 months (67.9% vs. 76.6%; p = 0.000); however, this varied significantly by acculturation level: 78.1% of Spanish-speaking Hispanic women compared to 66.1% of English-speaking Hispanic women breastfed for at least 2 months (p = 0.000). The effects of specific maternity care practices on duration varied across groups. Among non-Hispanic White, Native American, and English-speaking Hispanic women, breastfeeding while at the hospital had the strongest effect (AOR 2.09, 95% CI 1.67–2.61; AOR 2.71, 95% CI 2.08–3.52; and AOR 1.99, 95% CI 1.76–2.25, respectively). Among Spanish-speaking Hispanic women, being encouraged to breastfeed on demand had the strongest effect (AOR 5.179, 95% CI 3.86–6.94). Conclusions for Practice The effects of maternity care practices on breastfeeding duration vary by race, ethnicity, and acculturation level. Health care systems must acknowledge the diversity of their patient populations when seeking to develop and implement breastfeeding-friendly practices.

Intimate Partner Violence Screening in the Prenatal Period: Variation by State, Insurance, and Patient Characteristics Abstract Objective To measure the proportion of women screened for IPV during prenatal care; to assess the predictors of prenatal IPV screening. Methods We use the CDC's 2012 Pregnancy Risk Assessment Monitoring System, representative of births in 24 states and New York City (N = 28,581). We calculated descriptive and logistic regressions, weighted to deal with state-clustered observations. Results 49.2% of women in our sample reported being screened for IPV while pregnant. There were higher screening rates among women of color, and those who had not completed high school, never been married, received WIC benefits, initiated prenatal care in the first trimester, and were publicly insured. State screening rates varied (29.9–62.9%). Among states, mandated perinatal depression screening or training was positively associated with IPV screening. 3.6% of women in our sample reported prenatal IPV but were not screened during pregnancy. Conclusions for Practice Current efforts have not led to universal screening. We need to better understand when and why providers do not screen pregnant patients for IPV.

Male Partner Involvement in the Utilization of Hospital Delivery Services by Pregnant Women Living with HIV in Sub Saharan Africa: A Systematic Review and Meta-analysis Abstract Objective The level of male partner involvement in hospital delivery by pregnant women living with HIV in sub Saharan Africa (SSA) is low. We conducted a systematic review and meta-analysis to identify the approaches that are used in improving male partner involvement and their impact on the utilization of hospital delivery services by pregnant women living with HIV in SSA. Methods Ovid Medline, Embase, PsycINFO, Cochrane library, ClinicalTrials.gov, Web of Science and Current Controlled Trials were searched. Only studies carried out in SSA that reported an approach used in involving male partners and the impact on the uptake of hospital delivery services irrespective of the language and date of publication were included. Odds ratios were extracted or calculated from studies and combined in a meta-analysis using the statistical package Stata version 11.0. A forest plot was used to show the impact of various male involvement approaches. A funnel plot was used to report publication bias. Results From an initial 2316 non-duplicate articles, 08 articles were included in the systematic review and meta-analysis. The overall pooled OR was 1.56 (95% CI 1.45–1.68). After stratification, the odds ratios were: 1.51 (95% CI 1.38–1.65), 1.58 (95% CI 1.38–1.80), 3.47 (95% CI 2.16–5.58) for complex community interventions without community health workers (CHWs), complex community interventions with community health workers, and verbal encouragement respectively. The overall I-square was 91.0% but after stratification into the three different approaches, the I-squared within the complex community intervention without CHWs group was 0.0%. Conclusions for Practice Complex community interventions and verbal encouragement increase the utilization of hospital delivery services by pregnant women living with HIV in SSA. The overall heterogeneity was high but very low for studies that used complex community interventions without CHWs. More well conducted studies (including randomized controlled trials) are needed in future to add to the quality of evidence.

The South Carolina Multigenerational Linked Birth Dataset: Developing Social Mobility Measures Across Generations to Understand Racial/Ethnic Disparities in Adverse Birth Outcomes in the US South Abstract Objectives To describe the creation of a multigenerational linked dataset with social mobility measures for South Carolina (SC), as an example for states in the South and other areas of the country. Methods Using unique identifiers, we linked birth certificates along the maternal line using SC birth certificate data from 1989 to 2014, and compared the subset of records for which linking was possible with two comparison groups on sociodemographic and birth outcome measures. We created four multi-generational social mobility measures using maternal education, paternal education, presence of paternal information, and a summary score incorporating the prior three measures plus payment source for births after 2004. We compared social mobility measures by race/ethnicity. Results Of the 1,366,288 singleton birth certificates in SC from 1989 to 2014, we linked 103,194, resulting in 61,229 unique three-generation units. Mothers and fathers were younger and had lower education, and low birth weight was more common, in the multigenerational linked dataset than in the two comparison groups. Based on the social mobility summary score, only 6.3% of White families were always disadvantaged, compared to 30.4% of Black families and 13.2% of Hispanic families. Moreover, 32.8% of White families were upwardly mobile and 39.1% of Black families were upwardly mobile, but only 29.9% of Hispanic families were upwardly mobile. Conclusions for Practice When states are able to link individuals, birth certificate data may be an excellent source for examining population-level relationships between social mobility and adverse birth outcomes. Due to its location in the Deep South, the multigenerational SC dataset may be particularly useful for understanding racial/ethnic difference in social mobility and birth outcomes.

How Does the Healthfulness of the US Food Supply Compare to International Guidelines for Marketing to Children and Adolescents? Abstract Objectives Food marketing to children is pervasive and linked to increased preference and intake of unhealthy foods. The World Health Organization (WHO) developed the only multi-country nutrient criteria, and Chile recently released the world's most comprehensive regulation to identify foods that should not be marketed to children. Our objective was to examine the proportion of US packaged food and beverage products eligible for marketing to children under the WHO Europe Nutrient Profile Model (NPM) and the 2019 Chilean regulation. Methods Data for this study are from Label Insight's 2017 Open Access branded food database. Each product was assigned to one of 13 food categories, and nutritional content compared to both the NPM and Chilean criteria. The proportion of US products meeting criteria for marketing to children using both schemes was examined overall and by category. Agreement between the two criteria was examined using Cohen's Kappa. Results Of 17,740 US products, 21% were eligible to be marketed to children using the WHO criteria and 26% using the Chilean criteria. 'Egg and egg products' and 'Seafood' had the highest proportion of products eligible for marketing to children under both schemes. 'Confectionery' and 'Snack foods' had the lowest proportion eligible. Conclusions for practice The WHO NPM and Chilean criteria both restrict less healthy items from being marketed to children. Regulatory agencies in the US developing policies should consider the implementation of nutrient criteria to restrict the marketing of less healthy foods and beverages to children and adolescents.

Homelessness in Childhood and Adverse Childhood Experiences (ACEs) Abstract Objectives Research on adverse childhood experiences (ACEs) has provided a valuable framework for understanding associations between childhood maltreatment and family dysfunction and later poor health outcomes. However, increasing research suggests the number and types of childhood adversities measured warrants further examination. This study examines ACE exposure among adults who experienced homelessness in childhood, another type of childhood adversity. Methods This cross-sectional, descriptive study used the 2016 South Carolina (SC) Behavioral Risk Factor Surveillance System (BRFSS) survey and additional ACE modules to examine ACE exposure among SC adults and childhood homelessness. Standard descriptive statistics were calculated for each variable. Bivariate analysis compared types and number of ACEs by childhood homeless status. All analyses used survey sampling weights that accounted for the BRFSS sampling strategy. Results Data from 7490 respondents were weighted for analyses. Among the 215 respondents who reported homelessness in childhood, 68.1% reported experiencing four or more ACEs. In contrast, only 16.3% of respondents who reported no homelessness in childhood reported experiencing four or more ACEs. The percent of respondents was significantly higher for each of 11 ACEs among those who reported childhood homelessness, compared to those who did not. Conclusions for Practice Adults who reported homelessness in childhood also reported significantly greater exposure to higher numbers and types of ACEs than adults reporting no childhood homelessness. Study findings can be important in informing additional indicators important to the assessment of ACEs and to program developers or organizations that provide housing assistance to at-risk families and children.

Engaging Intergenerational Hispanics/Latinos to Examine Factors Influencing Childhood Obesity Using the PRECEDE–PROCEED Model Abstract Introduction Hispanics/Latinos are disproportionately affected by obesity in the U.S. Multiple factors place Hispanic/Latino children at risk for overweight, warranting guidance of a socio-ecologic approach to examine causes of obesity. The purpose of this study was to increase understanding of the factors that influence Hispanic/Latino childhood obesity through an intergenerational lens including children, parents/caregivers, and grandparents. Methods Eight focus groups were conducted with Hispanics/Latinos (N = 68 adults, N = 22 youth), using a semi-structured moderator's guide. Audio-recordings were transcribed, and thematically analyzed. Findings were categorized within the PRECEDE–PROCEED planning model. Results Adult participants were middle-aged (M = 37.8 ± 9.8 years) and youth were between the ages of 10–17 (M = 14.0 ± 1.8 years). Six themes emerged: eating habits, cultural perceptions of weight, acculturation, childhood obesity perceptions, economic issues, and generational differences. The major parental influence was lack of time to provide healthy meals due to socio-economic factors: long work hours and availability of nearby fast food options. Youth shared that childhood obesity is due to sedentary behaviors, permissive parenting and lack of parental modeling (the latter two factors often exacerbated by extended work schedules). Discussion Discordant perceptions about unhealthy eating habits emerged. Adults expressed a lack of nutritional knowledge and skills to prepare healthy meals; while adolescents emphasized permissive parenting styles and lack of discipline lead to unhealthy lifestyles in Hispanic families. Findings emphasize involving parents/caregivers and youth to understand discordant perceptions that can inform the development of prevention programs.

Leveraging Public Health Research to Inform State Legislative Policy that Promotes Health for Children and Families Abstract Purpose Engagement in policy is an essential public health service, with state legislatures serving as important arenas for activity on issues affecting children and families. However, a gap in communication often exists between policymakers and public health researchers who have the research knowledge to inform policy issues. We describe one tool for researchers to better leverage public health research to inform state legislative policymaking on issues of relevance to children and families. Description The Oregon Family Impact Seminar (OFIS), adapted from the Policy Institute for Family Impact Seminars, applies a systematic process to bring a synthesis of research findings on public health issues to state legislators using a six-step process: (1) identify candidate topics, (2) recruit legislative champions, (3) select the topic, (4) identify and prepare speakers, (5) host the presentations, and (6) develop and disseminate a research brief as a follow-up contact. Assessment Use of this model in Oregon has produced policy impact; for example, the 2015 presentation, "Two-Generation Approaches to Reduce Poverty," prompted ongoing dialogue culminating in a new statute to increase Earned Income Tax Credit for parents with young children. This approach also has strengthened relationships among researchers and legislators, which serves to streamline the OFIS process. Conclusion This model is an effective vehicle for leveraging public health research findings to inform state-level policy. This model also serves to connect researchers with opportunities to engage with policymakers to address significant public health problems, particularly those addressing social, economic, and environmental determinants of health for children and families.

Using Infant Mortality Data to Improve Maternal and Child Health Programs: An Application of Statistical Process Control Techniques for Rare Events Abstract Introduction The infant mortality rate (IMR) in the United States remains higher than most developed countries. To understand this public health issue and support state public health departments in displaying and analyzing data in ways that support learning, states participating in the Collaborative Improvement and Innovation Network to Reduce Infant Mortality (IM CoIIN) created statistical process control (SPC) charts for rare events. Methods State vital records data on live births and infant deaths was used to create U, T and G charts for Kansas and Alaska, two states participating in the IM CoIIN who sought methods to more effectively analyze IMR for subsets of their populations with infrequent number of deaths. The IMR and the number of days and number of births between infant deaths was charted for Kansas Non-Hispanic black population and six Alaska regions for the time periods 2013–2016 and 2011–2016, respectively. Established empirical patterns indicated points of special cause variation. Results The T and G charts for Kansas and G charts for Alaska depict points outside the upper control limit. These points indicate special cause variation and an increased number of days and/or births between deaths at these time periods. Discussion T and G charts offer value in examining rare events, and indicate special causes not detectable by U charts or other more traditional analytic methods. When small numbers make traditional analysis challenging, SPC has potential in the MCH field to better understand potential drivers of improvements in rare outcomes, inform decision making and take interventions to scale.

An Evaluation of Healthcare Use and Child Morbidity 4 Years After User Fee Removal in Rural Burkina Faso Abstract Objectives Increasing financial access to healthcare is proposed to being essential for improving child health outcomes, but the available evidence on the relationship between increased access and health remains scarce. Four years after its launch, we evaluated the contextual effect of user fee removal intervention on the probability of an illness occurring and the likelihood of using health services among children under 5. We also explored the potential effect on the inequality in healthcare access. Methods We used a comparative cross-sectional design based upon household survey data collected years after the intervention onset in one intervention and one comparison district. Propensity scores weighting was used to achieve balance on covariates between the two districts, which was followed by logistic multilevel modelling to estimate average marginal effects (AME). ResultsWe estimated that there was not a significant difference in the reduced probability of an illness occurring in the intervention district compared to the non-intervention district [AME 4.4; 95% CI  1.0–9.8)]. However, the probability of using health services was 17.2% (95% CI 15.0–26.6) higher among children living in the intervention district relative to the comparison district, which rose to 20.7% (95% CI 9.9–31.5) for severe illness episodes. We detected no significant differences in the probability of health services use according to socio-economic status [χ2 (5) = 12.90, p = 0.61]. Conclusions for Practice In our study, we found that user fee removal led to a significant increase in the use of health services in the longer term, but it is not adequate by itself to reduce the risk of illness occurrence and socioeconomic inequities in the use of health services.

Acta Biomaterialia

Bioprinting of stem cell expansion lattices Publication date: Available online 13 May 2019 Source: Acta Biomaterialia Author(s): Christopher D. Lindsay, Julien G. Roth, Bauer L. LeSavage, Sarah C. Heilshorn Abstract Stem cells have great potential in regenerative medicine, with neural progenitor cells (NPCs) being developed as a therapy for many central nervous system diseases and injuries. However, one limitation to the clinical translation of stem cells is the resource-intensive, two-dimensional culture protocols required for biomanufacturing a clinically-relevant number of cells. This challenge can be overcome in an easy-to-produce and cost-effective 3D platform by bioprinting NPCs in a layered lattice structure. Here we demonstrate that alginate biopolymers are an ideal bioink for expansion lattices and do not require chemical modifications for effective NPC expansion. Alginate bioinks that are lightly crosslinked prior to printing can shield printed NPCs from potential mechanical damage caused by printing. NPCs within alginate expansion lattices remain in a stem-like state while undergoing a 2.5-fold expansion. Importantly, we demonstrate the ability to efficiently remove NPCs from printed lattices for future down-stream use as a cell-based therapy. These results demonstrate that 3D bioprinting of alginate expansion lattices is a viable and economical platform for NPC expansion that could be translated to clinical applications. Graphical abstract

Stimulus-Responsive Polymeric Nanogels as Smart Drug Delivery Systems Publication date: Available online 13 May 2019 Source: Acta Biomaterialia Author(s): Sakineh Hajebi, Navid Rabiee, Mojtaba Bagherzadeh, Sepideh Ahmadi, Mohammad Rabiee, Hossein Roghani-Mamaqani, Mohammadreza Tahriri, Lobat Tayebi, Michael R. Hamblin Abstract Nanogels are three-dimensional nanoscale networks formed by physically or chemically cross-linking polymers. Nanogels have been explored as drug delivery systems due to their advantageous properties, such as biocompatibility, high stability, tunable particle size, drug loading capacity, and possible modification of the surface for active targeting by attaching ligands that recognize cognate receptors on the target cells or tissues. Nanogels can be designed to be stimulus responsive, and react to internal or external stimuli such as pH, temperature, light and redox, thus resulting in the controlled release of loaded drugs. This "smart" targeting ability prevents drug accumulation in non-target tissues and minimizes the side effects of the drug. This review aims to provide an introduction to nanogels, their preparation methods,and to discuss the design of various stimulus-responsive nanogels that are able to provide controlled drug release in response to particular stimuli. Statement of significance Smart and stimulus-responsive drug delivery is a rapidly growing area of biomaterial research. The explosive rise in nanotechnology and nanomedicine, has provided a host of nanoparticles and nanovehicles which may bewilder the uninitiated reader. This review will lay out the evidence that polymeric nanogels have an important role to play in the design of innovative drug delivery vehicles that respond to internal and external stimuli such as temperature, pH, redox, and light. Graphical abstract

Acta Journals Editors Transitioning to Joint Appointments Publication date: Available online 13 May 2019 Source: Acta Biomaterialia Author(s):

Superhydrophobic hierarchical fiber/bead composite membranes for efficient burns treatment Publication date: Available online 13 May 2019 Source: Acta Biomaterialia Author(s): Weichang Li, Qianqian Yu, Hang Yao, Yue Zhu, Paul D. Topham, Kan Yue, Li Ren, Linge Wang Abstract One of the current challenges in burn wound care is the development of multifunctional dressings that can protect the wound from bacteria or organisms and promote skin regeneration and tissue reconstitution. To this end, we report the design and fabrication of a composite electrospun membrane, comprised of electrospun polylactide : poly(vinyl pyrrolidone)/polylactide : poly(ethylene glycol) (PLA:PVP/PLA:PEG) core/shell fibers loaded with bioactive agents, as a functionally integrated wound dressing for efficient burns treatment. Different mass ratios of PLA:PVP in the shell were screened to optimize mechanical, physicochemical, and biological properties, in addition to controlled release profiles of loaded antimicrobial peptides (AMPs) from the fibers for desirable antibacterial activity. Fibroblasts were shown to readily adhere and proliferate when cultured on the membrane, indicating good in vitro cytocompatibility. The introduction of PLA beads by electrospraying on one side of the membrane resulted in biomimetic micro-nanostructures similar to those of lotus leaves. This designer structure rendered the composite membranes with superhydrophobic property to inhibit the adhesion/spreading of exogenous bacteria and other microbes. The administration of the resulting composite fibrous membrane on burnt skin in an infected rat model led to faster healing than a conventional product (sterile silicone membrane) and control detailed herein. These composite fibrous membranes loaded with bioactive drugs provide an integrated strategy for promoting burn wound healing and skin regeneration. Statement of Significance To address an urgent need in complex clinical requirements on developing a new generation of wound dressings with integrated functionalities. This article reports research work on a hierarchical fiber/bead composite membranes design, which combines a lotus-leaf-like superhydrophobic surface with drugs preloaded in the core and shell of fibers for effective burn treatment. This demonstrates a balance between simplified preparation processes and increased multifunctionality of the wound dressings. The creation of hierarchically structured surfaces can be readily achieved by electrospinning, and the composite dressings possessed a considerable mechanical strength, effective wound exudate absorption and permeability, good biocompatibility, broad antibacterial ability and promoting wound healing etc. Thus, our work unveils a promising strategy for the development of functionally integrated wound dressings for burn wound care. Graphical abstract

Graphene oxide containing self-assembling peptide hybrid hydrogels as a potential 3D injectable cell delivery platform for intervertebral disc repair applications Publication date: Available online 12 May 2019 Source: Acta Biomaterialia Author(s): Cosimo Ligorio, Mi Zhou, Jacek K. Wychowaniec, Xinyi Zhu, Cian Bartlam, Aline F. Miller, Aravind Vijayaraghavan, Judith A. Hoyland, Alberto Saiani Abstract Cell-based therapies have shown significant promise in tissue engineering with one key challenge being the delivery and retention of cells. As a result, significant efforts have been made in the past decade to design injectable biomaterials to host and deliver cells at injury sites. Intervertebral disc (IVD) degeneration, a major cause of back pain, is a particularly relevant example where a minimally-invasive cellular therapy could bring significant benefits specifically at the early stages of the disease, when a cell-driven process starts in the gelatinous core of the IVD, the nucleus pulposus (NP). In this present study we explore the use of graphene oxide (GO) as nano-filler for the reinforcement of FEFKFEFK (β-sheet forming self-assembling peptide) hydrogels. Our results confirm the presence of strong interactions between FEFKFEFK and GO flakes with the peptide coating and forming short thin fibrils on the surface of the flakes. These strong interactions were found to affect the bulk properties of hybrid hydrogels. At pH 4 electrostatic interactions between the peptide fibres and the peptide-coated GO flakes are thought to govern the final bulk properties of the hydrogels while at pH 7, after conditioning with cell culture media, electrostatic interactions are removed leaving the hydrophobic interactions to govern hydrogel final properties. The GO-F820 hybrid hydrogel, with mechanical properties similar to the NP, was shown to promote high cell viability and retained cell metabolic activity in 3D over the 7 days of culture and therefore shown to harbour significant potential as an injectable hydrogel scaffold for the in-vivo delivery of NP cells. Statement of significance Short self-assembling peptide hydrogels (SAPHs) have attracted significant interest in recent years as they can mimic the natural extra-cellular matrix, holding significant promise for the ab-initio design of cells' microenvironments. Recently the design of hybrid hydrogels for biomedical applications has been explored through the incorporation of specific nanofillers. In this study we exploited graphene oxide (GO) as nanofiller to design hybrid injectable 3Dscaffolds for the delivery of nucleus pulposus cells (NPCs) for intervertebral disc regeneration. Our work clearly shows the presence of strong interactions between peptide and GO, mimicking the mechanical properties of the NP tissue and promoting high cell viability and metabolic activity. These hybrid hydrogels therefore harbour significant potential as injectable scaffolds for the in-vivo delivery of NPCs. Graphical abstract

Synchrotron tomography of intervertebral disc deformation quantified by digital volume correlation reveals microstructural influence on strain patterns Publication date: Available online 11 May 2019 Source: Acta Biomaterialia Author(s): C.M. Disney, A. Eckersley, J.C. McConnell, H. Geng, A.J. Bodey, J.A Hoyland, P.D. Lee, M.J. Sherratt, B.K. Bay Abstract The intervertebral disc (IVD) has a complex and multiscale extracellular matrix structure which provides unique mechanical properties to withstand physiological loading. Low back pain has been linked to degeneration of the disc but reparative treatments are not currently available. Characterising the disc's 3D microstructure and its response in a physiologically relevant loading environment is required to improve understanding of degeneration and to develop new reparative treatments. In this study, techniques for imaging the native IVD, measuring internal deformation and mapping volumetric strain were applied to an in situ compressed ex vivo rat lumbar spine segment. Synchrotron X-ray micro-tomography (synchrotron CT) was used to resolve IVD structures at microscale resolution. These image data enabled 3D quantification of collagen bundle orientation and measurement of local displacement in the annulus fibrosus between sequential scans using digital volume correlation (DVC). The volumetric strain mapped from synchrotron CT provided a detailed insight into the micromechanics of native IVD tissue. The DVC findings showed that there was no slipping at lamella boundaries, and local strain patterns were of a similar distribution to the previously reported elastic network with some heterogeneous areas and maximum strain direction aligned with bundle orientation, suggesting bundle stretching and sliding. This method has the potential to bridge the gap between measures of macro-mechanical properties and the local 3D micro-mechanical environment experienced by cells. This is the first evaluation of strain at the micro scale level in the intact IVD and provides a quantitative framework for future IVD degeneration mechanics studies and testing of tissue engineered IVD replacements. Statement of Significance Synchrotron in-line phase contrast X-ray tomography provided the first visualisation of native intact intervertebral disc microstructural deformation in 3D. For two annulus fibrosus volumes of interest, collagen bundle orientation was quantified and local displacement mapped as strain. Direct evidence of microstructural influence on strain patterns could be seen such as no slipping at lamellae boundaries and maximum strain direction aligned with collagen bundle orientation. Although disc elastic structures were not directly observed, the strain patterns had a similar distribution to the previously reported elastic network. This study presents technical advances and is a basis for future X-ray microscopy, structural quantification and digital volume correlation strain analysis of soft tissue. Graphical abstract

Nonlinear elasticity of the lung extracellular microenvironment is regulated by macroscale tissue strain Publication date: Available online 11 May 2019 Source: Acta Biomaterialia Author(s): Ignasi Jorba, Gabriel Beltrán, Bryan Falcones, Béla Suki, Ramon Farré, José Manuel García-Aznar, Daniel Navajas Abstract The extracellular matrix (ECM) of the lung provides physical support and key mechanical signals to pulmonary cells. Although lung ECM is continuously subjected to different stretch levels, detailed mechanics of the ECM at the scale of the cell is poorly understood. Here, we developed a new polydimethylsiloxane (PDMS) chip to probe nonlinear mechanics of tissue samples with atomic force microscopy (AFM). Using this chip, we performed AFM measurements in decellularized rat lung slices at controlled stretch levels. The AFM revealed highly nonlinear ECM elasticity with the microscale stiffness increasing with tissue strain. To correlate micro- and macroscale ECM mechanics, we also assessed macromechanics of decellularized rat lung strips under uniaxial tensile testing. The lung strips exhibited exponential macromechanical behavior but with stiffness values one order of magnitude lower than at the microscale. To interpret the relationship between micro- and macromechanical properties, we carried out a finite element (FE) analysis which revealed that the stiffness of the alveolar cell microenvironment is regulated by the global strain of the lung scaffold. The FE modeling also indicates that the scale dependence of stiffness is mainly due to the porous architecture of the lung parenchyma. We conclude that changes in tissue strain during breathing result in marked changes in the ECM stiffness sensed by alveolar cells providing tissue-specific mechanical signals to the cells. Statement of significance The micromechanical properties of the extracellular matrix (ECM) are a major determinant of cell behavior. The ECM is exposed to mechanical stretching in the lung and other organs during physiological function. Therefore, a thorough knowledge of the nonlinear micromechanical properties of the ECM at the length scale that cells probe is required to advance our understanding of cell-matrix interplay. We designed a novel PDMS chip to perform atomic force microscopy measurements of ECM micromechanics on decellularized rat lung slices at different macroscopic strain levels. For the first time, our results reveal that the microscale stiffness of lung ECM markedly increases with macroscopic tissue strain. Therefore, changes in tissue strain during breathing result in variations in ECM stiffness providing tissue-specific mechanical signals to lung cells. Graphical abstract

Quantum Dots in Biomedical Applications Publication date: Available online 11 May 2019 Source: Acta Biomaterialia Author(s): Angela M. Wagner, Jennifer M. Knipe, Gorka Orive, Nicholas A. Peppas Abstract Semiconducting nanoparticles, more commonly known as quantum dots, possess unique size and shape dependent optoelectronic properties. In recent years, these unique properties have attracted much attention in the biomedical field to enable real-time tissue imaging (bioimaging), diagnostics, single molecule probes, and drug delivery, among many other areas. The optical properties of quantum dots can be tuned by size and composition, and their high brightness, resistance to photobleaching, multiplexing capacity, and high surface-to-volume ratio make them excellent candidates for intracellular tracking, diagnostics, in vivo imaging, and therapeutic delivery. We discuss recent advances and challenges in the molecular design of quantum dots are discussed, along with applications of quantum dots as drug delivery vehicles, theranostic agents, single molecule probes, and real-time in vivo deep tissue imaging agents. We present a detailed discussion of the biodistribution and toxicity of quantum dots, and highlight recent advances to improve long-term stability in biological buffers, increase quantum yield following bioconjugation, and improve clearance from the body. Last, we present an outlook on future challenges and strategies to further advance translation to clinical application. Statement of Significance Semiconducting nanoparticles, commonly known as quantum dots, possess unique size and shape dependent electrical and optical properties. In recent years, they have attracted much attention in biomedical imaging to enable diagnostics, single molecule probes, and real-time imaging of tumors. This review discusses recent advances and challenges in the design of quantum dots, and highlights how these strategies can further advance translation to clinical applications. Graphical abstract

Development of biocompatible and fully bioabsorbable PLA/Mg films for tissue regeneration applications Publication date: Available online 11 May 2019 Source: Acta Biomaterialia Author(s): A. Ferrández-Montero, M. Lieblich, J.L. González-Carrasco, R. Benavente, V. Lorenzo, R. Detsch, A.R. Boccaccini, B. Ferrari Abstract During recent years, Mg reinforced polylactic acid (PLA) composites have emerged as potential biocompatible and bioabsorbable materials for biomedical applications. It has been shown that Mg particles added to a matrix based on a biodegradable polymer can address the lack of bioactivity and the low mechanical properties of the polymers and, furthermore, it can counteract the detrimental effects associated to the high degradation rate of Mg, as alcalinization and elevated H2 release. Additionally, the polymer can protect the Mg particles, by tailoring their degradation rate. Former processing of these composites performed by extrusion, compression and injection molding employed Mg contents up to 10 wt.%. Higher amounts of Mg resulted in heterogeneous materials and thermally degraded matrices, with the corresponding higher degradation rate. In the present work, Mg reinforced PLA films with Mg content as high as 50 wt.% were obtained without compromising the thermal stability of the polymer. Firstly, a successful dispersion of Mg microparticles was achieved by a breakthrough in processing introducing a colloidal step where organic additives were added to modify the Mg particle surface and promote a chemically stable suspension. The resulting colloidal suspension was then used as feedstock to obtain composite films by tape casting. The films show advantageous in vitro behaviour in terms of degradation, hydrogen release and oxygen permeability. In addition, the viability with fibroblastic cells (MEF) opens a window of opportunity for these composite films as bioabsorbable material for tissue engineering and wound dressing applications. Statement of Significance Magnesium materials have extraordinary biodegradable properties and bioactive behavior due to release of Mg2+ ions, which offer a promising opportunity for their applicability as biomaterials for tissue regeneration. However, Mg is one of the most reactive metals with a high degradation rate. In contact with water produces H2, associated with a risk of failure of the implant. One alternative to minimize this drawback is the use of Mg particles surrounded by a biodegradable biocompatible polymer such as polylactic acid (PLA) to obtain PLA/Mg composites. In this work we processed Mg reinforced PLA in the shape of films that would be suitable for tissue regeneration. In vitro behavior of PLA/Mg films demonstrated that Mg2+ ions increase the fibroblastic cells growth. Graphical abstract

Osteogenic and pH Stimuli-responsive Self-healing Coating on Biomedical Mg-1Ca Alloy Publication date: Available online 11 May 2019 Source: Acta Biomaterialia Author(s): Pan Xiong, Zhaojun Jia, Wenhao Zhou, Jianglong Yan, Pei Wang, Wei Yuan, Yangyang Li, Yan Cheng, Zhenpeng Guan, Yufeng Zheng Abstract Various coatings have been used to slow down the corrosion rate of biomedical magnesium alloys. However, these coatings usually act only as passive barriers. It is much more desirable to endow such coatings with active, biocorrosion-responsive self-repairing capacity. In the present work, a self-healing coating system (denoted as "silk-PA") was constructed in the form of a sandwich architecture of fluoride precoating (bottom), silk-phytic acid (PA) coating (middle), and silk fibroin coating (top). Here, PA was loaded in the middle coating as a corrosion inhibitor by harnessing its strong chelating ability toward dissolving Mg2+ and Ca2+ ions. The self-healing property was evaluated by scratch and SVET tests, and the corrosion resistance was evaluated by in vitro immersion and electrochemical measurements. The results showed that the silk-PA manifested intriguing self-healing capacity with pH responsiveness, hence profiting the corrosion resistance of the Mg-1Ca alloy. The biocompatibility and osteogenic activity of the coating system were further evaluated using MC3T3-E1 cells, and it demonstrated favorable responses in multiple cellular behaviors, i.e., adherence, spreading, proliferation, and differentiation. These findings open new opportunities in the study of self-healing coatings for protection against corrosion in biomedical Mg alloys. Statement of significance In the present study, a self-healing coating system with pH stimuli-responsiveness as well as osteogenic activity was fabricated on Mg-1Ca alloy by integrating a silk fibroin barrier coating, a silk fibrin/phytic acid composite coating, and a fluoride pre-coating. This coating system demonstrated interesting self-healing ability in comparison to traditional surface modification layers. Furthermore, self-healing ability enhanced corrosion resistance of biomedical magnesium alloys, while effective compositions of the coating system endowed the substrate with osteogenic activity. This work gives some new insights into smart surface modification for biomedical Mg alloys. Graphical abstract

Maladies Professionnelles et de l'Environnement

Influence du mal de mer sur le travail de chercheurs embarqués à bord de navires océanographiques français Publication date: Available online 12 May 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s): D. Jégaden, M. Menaheze, D. Lucas Résumé Objectif L'objectif de ce travail est d'étudier l'importance et le ressenti sur le poste de travail à bord du mal de mer chez les océanographes. Méthode L'étude a été réalisée par un questionnaire anonyme adressé à tous les chercheurs et techniciens devant embarquer régulièrement (une à deux fois par an, pour des périodes de huit à cinquante jours) en missions côtières ou hauturières. Résultats Deux-cent-vingt-trois océanographes (151 hommes et 72 femmes) ont répondu à l'enquête. Cent-quatre-vingt-huit d'entre eux (91,7 % des femmes et 80,8 % des hommes) disent être sujets au mal de mer, soit occasionnellement (69 %), soit à chaque embarquement où l'on retrouve une prédominance féminine (23,6 % contre 11,3 % chez les hommes). Les symptômes majeurs sont des nausées (82 %) et les vomissements (56 %), suivis de pâleur, bâillements, sueurs froides et somnolence, fatigue intense et désintérêt au travail (de 35 à 45 %). Soixante pour cent des agents pensent que le mal de mer a une influence sur le bon déroulement de leur mission, en touchant d'abord leur moral (50 %), leur relation aux autres (23 %), et en présentant un risque accru d'accidents tels que chutes, accidents sur machines ou dans les laboratoires (40 %). Les traitements antinaupathiques produisent aussi des effets délétères sur leur poste de travail (somnolence, troubles visuels). Discussion/conclusion Le mal de mer a un impact non négligeable dans les missions des océanographes, malgré le fait que cette pathologie ne soit que très rarement évoquée spontanément lors des visites médicales du travail. Si les traitements pharmacologiques peuvent aussi induire des gênes, il existe actuellement des traitements par rééducation optocinétique qui peuvent durablement réduire la survenue de cette pathologie en mer. Summary Purpose of the study The objective of this work is to study the importance and the effects of seasickness on the workstation aboard, among oceanographers. Method The study was conducted by an anonymous questionnaire sent to all researchers and technicians who regularly board (once or twice a year, for periods of eight to fifty days) on coastal or offshore missions. Results Two hundrend and twenty-three oceanographers (151 men and 72 women) responded to the survey. One hundrend and eighty-eight of them (91.7% of women and 80.8% of men) report being seasick, either occasionally (69%) or at each boarding where there is female predominance (23,6% vs. 11.3% for men). The major symptoms are nausea (82%) and vomiting (56%), followed by pallor, yawning, cold sweat and drowsiness, intense fatigue and disinterest in work (35 to 45%). 60% of the workers think that seasickness has an influence on the success of their mission, by first affecting their morale (50%), their relationship with others (23%), and by presenting an increased risk of accidents such as falls, accidents on machines or in laboratories (40%). Antinaupathic treatments also produce deleterious effects on their workstation (drowsiness, visual disturbances). Conclusion Seasickness has a significant impact on the missions of oceanographers, despite the fact that this pathology is rarely mentioned spontaneously during occupational medical examination. If pharmacological treatments can also induce discomfort, there are currently treatments by optokinetic rehabilitation that can sustainably reduce the occurrence of this pathology at sea.

Exposition professionnelle au radon : actualités et surveillance médicale Publication date: Available online 25 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s):

Santé et maintien en emploi : prévention de la désinsertion professionnelle des travailleurs. Recommandations pour la pratique clinique (février 2019) Publication date: Available online 24 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s): Haute Autorité de la santé, Société française de médecine du travail

Exposition professionnelle au radon : actualités et surveillance médicale Publication date: Available online 24 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s):

Réunions et congrès Publication date: Available online 23 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s):

Législation Publication date: Available online 23 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s):

Revue de presse scientifique Publication date: Available online 23 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s):

Étude de l'exposition aux fumées d'incendie des sapeurs-pompiers affectés en structure de feu contrôlé Publication date: Available online 22 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s): A. Allonneau, S. Mercier, A. Menguy-Fleuriot, S.C. Luu, C. Louyot, A. Nicolas, D. Jost, N. Jacques, M. Bignand Résumé Problématique et objectif Les sapeurs-pompiers sont exposés aux fumées d'incendie par leurs activités opérationnelles et d'instruction. L'objectif de cette étude était d'évaluer le niveau de contamination au benzène et aux hydrocarbures aromatiques polycycliques au sein d'une population de formateurs, au travers de l'analyse d'indicateurs biologiques urinaires d'exposition et par des prélèvements d'atmosphère. Méthode Étude observationnelle prospective réalisée dans le cadre d'un suivi de médecine du travail. Nous avons constitué 2 groupes : « exposé » comportant 8 pompiers formateurs affectés en structure de feu contrôlé et « non exposés » composé de 8 pompiers affectés au service médical. Après accord des participants, nous avons analysé l'excrétion urinaire du benzène, du 1-hydroxypyrène, du 3 hydroxybenzo(a)pyrène et des 1 et 2 naphtols. Quatre prélèvements ont été effectués sur une semaine : le lundi en début de poste (mesurer la concentration résiduelle après deux jours sans exposition), le lundi soir (étudier l'exposition de la journée), le mardi à la mi-journée (pic d'excrétion), et le vendredi en fin de poste (exposition cumulée de la semaine). Les métrologies d'ambiance ont mesuré la présence de composés organiques volatils (benzène, hydrocarbures aromatiques polycycliques, aldéhydes), fraction inhalable des particules et monoxyde de carbone pour les périodes sans port d'appareil respiratoire isolant. Résultats Les valeurs obtenues restaient le plus souvent inférieures aux valeurs limites biologiques, mais il existait une tendance au cours de la semaine à l'augmentation du benzène, du 1-hydroxypyrène et du 3 hydroxybenzoapyrène, chez les sujets « exposés » versus « non exposés ». Les métrologies d'ambiance montraient que les valeurs limites d'exposition professionnelles du benzène et du naphtalène n'étaient pas dépassées contrairement à celles du benzo(a)pyrène et du pyrène. Conclusions La contamination semblait faible, car les valeurs obtenues étaient la plupart du temps inférieures aux valeurs de référence. Une contamination cutanée était à suspecter du fait de l'augmentation préférentielle des 2 naphtols. Summary Purpose of the study Firefighters are exposed to fire smoke through their operational and training activities. The aim of this study was to evaluate the level of contamination of benzene and polycyclic aromatic hydrocarbons in a population of trainers through the analysis of urinary biological exposure indicators and atmospheric samples. Methods A prospective and observational study was carried out in the framework of health care at work. We formed 2 groups: "exposed" with 8 firefighter trainers assigned to a controlled fire structure, and "unexposed" with 8 firefighters assigned to the medical service. With the agreement of the participants, we analyzed the urinary excretion of benzene, 1-hydroxypyrene, 3- hydroxybenzo(a)pyrene, and 1 and 2 naphthols. Four samples were taken over a week: Monday at the beginning of shift (measuring the residual concentration after two days without exposure), Monday evening (measuring the exposure of the day), Tuesday at midday (peak of excretion), and Friday at the end of shift (cumulative exposure of the week). Environmental metrology has measured the presence of volatile organic compounds (benzene, polycyclic aromatic hydrocarbons, aldehydes), inhalable particulate fraction, and carbon monoxide for periods without selfcontained breathing apparatus. Results The values obtained were mostly lower than the biological limit values, but they increased during the week for benzene, 1-hydroxypyrene, and 3-hydroxybenzoapyrene in the exposed group versus the unexposed group. Environmental metrology showed that the occupational exposure limit values for benzene and naphthalene were not exceeded, in contrast to benzo(a)pyrene and pyrene. Conslusion Contamination appeared weak because the values obtained were generally lower than the reference values. Cutaneous contamination was suspected due to the preferential increase of 2 naphthols.

Évaluation des risques sanitaires chez des salariés travaillant en station de séchage thermique de boues d'épuration : dosage urinaire du cadmium Publication date: Available online 17 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s): S. Pachura, C. Block, A. Stoufflet Résumé Une population grandissante, l'amélioration des procédés d'épuration des eaux usées et une réglementation de plus en plus draconienne en termes de traitement de ces eaux, entraînent une augmentation de la production de boues de station d'épuration (STEP). Il est impératif de traiter ce déchet, et diverses techniques voient le jour afin d'en réduire les volumes et/ou de le valoriser. Or ces boues peuvent contenir des polluants pour lesquels il existe des teneurs maximales à ne pas dépasser lors de la valorisation en filières agricoles, ceci pour préserver l'environnement et ne pas impacter la chaîne trophique. Aussi les études s'intéressent à l'impact sanitaire chez les agriculteurs qui pratiquent l'épandage ainsi que chez les consommateurs. Quid des opérateurs dans les STEP qui sont en charge de traiter ces boues ? À ce jour, aucune information dans la littérature ne traite de cette question. Cette étude se propose donc d'évaluer le risque sanitaire de ces boues dans un établissement d'assainissement des eaux usées qui utilise un traitement par un séchage thermique. Ce procédé est potentiellement émetteur de poussières, qui contiennent des concentrations plus ou moins importantes en éléments traces métalliques, en particulier le cadmium qui a été choisi comme traceur de cette pollution. Des dosages urinaires du cadmium ont été réalisés chez 7 salariés en charge du sécheur. Ils ont démontré que les concentrations en cadmium étaient équivalentes voire inférieures à celles de la population générale. Les déterminants spécifiques de l'entreprise comme les modes opératoires, les équipements de protection collective ou individuelle, et qui concourent à la préservation de la santé de ces salariés ont été identifiés et leur efficacité ainsi confirmée. Summary A growing population, the improvement of wastewater treatment processes and an increasingly stringent regulation in terms of treatment of these waters, lead to an increase in the production of sewage sludge. It is imperative to treat this waste, and various techniques are emerging in order to reduce volumes and/or enhance it. However, these sludges can contain pollutants for which there are maximum levels that should not be exceeded during development in agricultural sectors, this to preserve the environment and not impacting the food chain. As a result, the studies focus on the health impact on farmers who practice spreading and on consumers. What about the operators in the wastewater treatment plant ("WWTP") who are in charge of treating these sludges? To date, no information in the literature addresses this issue. This study therefore proposes to evaluate the health risk of this sludge in a WWTP that uses a treatment by thermal drying. This process potentially emits dust, which contain more or less significant concentrations of trace metal elements, in particular cadmium which has been chosen as a tracer of this pollution. Cadmium urinary dosages were performed on 7 employees in charge of the dryer. They demonstrated that cadmium levels in the urine were equivalent to or even lower than levels in general population. The specific determinants of the company, such as operating procedures, collective or individual protection equipment, that contribute to the preservation of these employees' health have been identified, and their effectiveness thus confirmed.

Chariot et transpalette en logistique : comparaison d'OSEV 2017 pour évaluer l'exposition journalière aux vibrations corps entier A(8) des caristes, concordance des résultats avec des mesurages terrain (suite) Publication date: Available online 16 April 2019 Source: Archives des Maladies Professionnelles et de l'Environnement Author(s): M. Le Bras, R. Petitfour Résumé Problématique et objectifs « Comment réaliser une évaluation fiable de l'exposition journalière aux vibrations corps entier A(8) sans mesure métrologique ? ». L'Association interprofessionnelle des centres médicaux sociaux de santé au travail de la région Île-de-France (ACMS) a été recontactée pour réévaluer l'outil OSEV2017. L'objectif est d'optimiser les ressources du service et des adhérents en minimisant les mesurages. Méthodes Cent-seize mesures, issues des études ACMS de terrain, réalisées en logistique de 2009 à 2014 avec des chariots frontaux et des transpalettes, ont été analysées en 2015. Leurs éléments observés ont servi de paramètres dans différents outils réputés : Whole Body Vibration calculator (WBV-HSE), OSEV2015 et OSEV2017 pour mesurer l'effet de la programmation. Les valeurs A(8) des caristes provenant des études de terrain sont confrontées à celles issues des trois outils, avec en référence les seuils réglementaires (0,5 et 1,15 m/s2), illustrées graphiquement par « box plot ». L'interprétation probabiliste pour comparer les résultats des outils et des études ACMS terrain est fondée sur les calculs de sensibilité et de spécificité, et sur l'étude de la concordance entre deux méthodes par approche graphique « Bland-Altman plots ». Résultats Les outils étudiés Whole Body Vibration calculator (WBV-HSE), et OSEV2015 ont tendance à surestimer l'exposition journalière A(8) par rapport aux études ACMS de terrain pour les deux types d'engins. Les résultats d'OSEV2017 sont plus proches des valeurs terrain (biais+ ou −0,02). La sensibilité et la spécificité sont plus élevées pour les TEP que pour les chariots frontaux. Conclusion L'outil d'estimation OSEV2017 est plus fiable et peut être utilisé pour évaluer le risque vibratoire. L'amélioration d'OSEV a été efficiente (biais faibles). Summary Purpose of the study "How to carry out a reliable assessment of the daily exposure whole body vibrations A (8) without measurements?" The interprofessional Association of the Social Medical centers of occupational health in Île-de-France region (ACMS) has been contacted to reassess the OSEV2017 tool. The objective of this study are to optimize the resources of the association and their members by minimizing measuring. Methods In 2015, the results of 116 ACMS vibrations measurements, carried out in logistics from 2009 to 2014 with forklift trucks and pallet trucks with on-board standing drivers, were analyzed. Their observed elements were used as parameters in three famous tools: Whole Body Vibration calculator (WBV-HSE), OSEV2015, OSEV2017. Values A(8) of the drivers coming from the measurement campaign are confronted with those from the three tools, in reference to the lawful thresholds (0.5 and 1.15 m/s2), illustrated graphically by "box plot". To compare the results from the tools and measurement campaign, the probabilistic interpretation is founded on calculations of the sensitivity and the specificity, and on the study of the agreement between two methods by graphic approach "Bland-Altman plots". Results The studied tools Whole Body Vibration calculator (WBV-HSE), et OSEV2015 tend to over-estimate daily exposure A (8) compared to measurement studies for the two types of trucks. The results of OSEV2017 are closer to field values (bias+ or −0.02). Around 0.5 m/s2, sensitivity and specificity are higher for pallet trucks than for forklift trucks. Conclusion The OSEV2017 estimation tool is consistent with ground values and can be used to assess vibratory risk. The improving of OSEV has been efficient (low biases).

Dairy Science

Technical note: Evaluation of a novel enzymatic method to predict in situ undigested neutral detergent fiber of forages and nonforage fibrous feeds Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): A. Gallo, S. Bruschi, F. Masoero ABSTRACT The purpose of this study was to optimize the conditions of a previously proposed enzymatic method used to estimate in situ undigested neutral detergent fiber (uNDF). We used a multi-step enzymatic approach, in which samples were first solubilized in NaOH solutions as a preincubation (PreInc) phase. After rinsing, samples were incubated (24 h at 39°C) in a buffered solution (pH 6) containing hemicellulase, cellulase, and Viscozyme L enzymes (Sigma-Aldrich s.r.l., Milan, Italy), followed by incubation (24 h at 39°C) in a buffered solution (pH 5) containing xylanase. Two sets of experiments were performed: a calibration trial (that tested different PreInc conditions on 9 selected forages) and a validation trial (that verified the results by testing multiple samples of 6 different forage types and a group of fibrous by-products). In the calibration trial, samples (300 mg in Ankom F57 filter bags; Ankom Technology Corp., Fairport, NY) were preincubated at 39°C in a 0.1 M NaOH solution for 90, 180, or 240 min, or in 0.2, 0.5, 1.0, or 2.0 M NaOH solution for 90 min. The results indicated that the best PreInc method, in terms of intra-laboratory repeatability and estimation of reference in situ values, was 90 min in a 0.2 M NaOH solution. Thus, we used this PreInc condition to determine enzymatic uNDF of 257 samples in the validation trial. Although the selected method generally had good accuracy in predicting in situ uNDF, inconsistencies were noted for certain forage types. Overall, when enzymatic uNDF was used to predict the in situ uNDF of all samples, the regression was satisfactory (intercept = 7.098, slope = 0.920, R2 = 0.73). The regression models developed for alfalfa hays, corn silages, and small grain silages had also acceptable regression performances and mean square error of prediction (MSEP) values, and the main sources of MSEP variation were error due to incomplete (co)variation and random error. Even when R2 values were >0.70, the MSEP value of the regression model for grass hays was 149.55, and that for nonforage fibrous feeds was 155.16. Although enzymatic uNDF partially overestimated the in situ uNDF, particularly in grass silages, the proposed procedure seems to be promising for accurately predicting in situ uNDF, because it generally had good repeatability and provided satisfactory estimates of in situ uNDF.

Are dietary strategies to mitigate enteric methane emission equally effective across dairy cattle, beef cattle, and sheep? Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): Sanne van Gastelen, Jan Dijkstra, André Bannink ABSTRACT The digestive physiology of ruminants is sufficiently different (e.g., with respect to mean retention time of digesta, digestibility of the feed offered, digestion, and fermentation characteristics) that caution is needed before extrapolating results from one type of ruminant to another. The objectives of the present study were (1) to provide an overview of some essential differences in rumen physiology between dairy cattle, beef cattle, and sheep that are related to methane (CH4) emission; and (2) to evaluate whether dietary strategies to mitigate CH4 emission with various modes of action are equally effective in dairy cattle, beef cattle, and sheep. A literature search was performed using Web of Science and Scopus, and 94 studies were selected from the literature. Per study, the effect size of the dietary strategies was expressed as a proportion (%) of the control level of CH4emission, as this enabled a comparison across ruminant types. Evaluation of the literature indicated that the effectiveness of forage-related CH4 mitigation strategies, including feeding more highly digestible grass (herbage or silage) or replacing different forage types with corn silage, differs across ruminant types. These strategies are most effective for dairy cattle, are effective for beef cattle to a certain extent, but seem to have minor or no effects in sheep. In general, the effectiveness of other dietary mitigation strategies, including increased concentrate feeding and feed additives (e.g., nitrate), appeared to be similar for dairy cattle, beef cattle, and sheep. We concluded that if the mode of action of a dietary CH4 mitigation strategy is related to ruminant-specific factors, such as feed intake or rumen physiology, the effectiveness of the strategy differs across ruminant types, whereas if the mode of action is associated with methanogenesis-related fermentation pathways, the strategy is effective across ruminant types. Hence, caution is needed when translating effectiveness of dietary CH4mitigation strategies across different ruminant types or production systems.

Invited review: Milk lactose—Current status and future challenges in dairy cattle Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): A. Costa, N. Lopez-Villalobos, N.W. Sneddon, L. Shalloo, M. Franzoi, M. De Marchi, M. Penasa ABSTRACT Lactose is the main carbohydrate in mammals' milk, and it is responsible for the osmotic equilibrium between blood and alveolar lumen in the mammary gland. It is the major bovine milk solid, and its synthesis and concentration in milk are affected mainly by udder health and the cow's energy balance and metabolism. Because this milk compound is related to several biological and physiological factors, information on milk lactose in the literature varies from chemical properties to heritability and genetic associations with health traits that may be exploited for breeding purposes. Moreover, lactose contributes to the energy value of milk and is an important ingredient for the food and pharmaceutical industries. Despite this, lactose has seldom been included in milk payment systems, and it has never been used as an indicator trait in selection indices. The interest in lactose has increased in recent years, and a summary of existing information about lactose in the dairy sector would be beneficial for the scientific community and the dairy industry. The present review collects and summarizes knowledge about lactose by covering and linking several aspects of this trait in bovine milk. Finally, perspectives on the use of milk lactose in dairy cattle, especially for selection purposes, are outlined.

Housing tiestall dairy cows in deep-bedded pens during an 8-week dry period: Effects on lying time, lying postures, and rising and lying-down behaviors Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): E. Shepley, G. Obinu, T. Bruneau, E. Vasseur ABSTRACT Dairy cow lying behavior is useful in determining the cow's level of welfare, as well as in determining how her environment may affect her comfort and ease of movement. In tiestall systems, cows usually remain in a stall for the duration of their lactation. The dry period offers a unique opportunity to provide alternative housing to the cow with minimal effects on farm housing and management. Our objective was to determine whether housing tiestall cows in deep-bedded pens over an 8-wk dry period altered lying time, lying and rising ability, or lying postures. At dry-off, 20 cows, paired by parity and calving date, were randomly assigned to a deep-bedded loose pen (LP) or a tiestall (TS). Leg-mounted pedometers measured lying time. Rising and lying ability were measured using 6 events of rising and lying from 24-h video recordings taken once a week per cow. Sequenced images (1/min) from the 24-h recordings were used to document lying postures and locations for each cow. Data were analyzed for the early (first week of dry-off), mid, and late (week before calving) terms of the dry period. Lying time did not differ between LP and TS but was numerically higher for LP than TS cows (14.4 vs. 13.0 h/d, respectively). Contact with stall or pen confines when lying down was 5 times higher in TS than LP. The increased contact, coupled with a higher occurrence of hindquarter shifting in the late term, led to higher overall abnormal lying behaviors in TS. Contact with the stall upon rising increased in the late term for TS cows. Cows housed in loose pens also exhibited greater variation in hind-leg postures, keeping legs tucked 20% less often in favor of alternative postures. Stall hardware (e.g., tie rail, dividers) may have affected the ease of transition between lying and standing, leading to higher levels of contact with the stall. Loose-pen cows are able to assume more postures than TS cows when provided more space, possibly allowing them to orient themselves in ways that provide greater comfort. Lying surface in the deep-bedded loose pen may ease the cow's lying-down and rising movements and lead to the higher lying time found with LP cows. Overall, aspects of the stall largely contributed to differences in lying behaviors, warranting further study into whether freestall systems would yield similar outcomes. Improving our concept of ease of movement related to lying and quality of rest in dairy cows, through evaluating lying behaviors in different housing systems, allows for better recommendations on viable alternative housing options.

Lameness and lying behavior in grazing dairy cows Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): A.J. Thompson, D.M. Weary, J.A. Bran, R.R. Daros, M.J. Hötzel, M.A.G. von Keyserlingk ABSTRACT Lameness is a serious welfare issue for dairy cows. To date, the majority of studies have focused on its effect on health and behavior at the herd level. The objectives of this study were to identify (1) between-cow and (2) within-cow changes in lying behavior associated with consistent and changing lameness status in grazing dairy cows. Previous studies of lying behavior in grazing dairy cows have not considered the effect of precipitation, so a third aim was to determine the effect of precipitation on lying behavior. A total of 252 dairy cows from 6 pasture-based farms in southern Brazil were gait scored weekly to assess lameness using a 5-point scale [1–5, numerical rating score (NRS)] for 4 consecutive weeks. Cows were considered to have consistent lameness if they were scored as lame (NRS ≥3) on each of the 4 visits and considered to have a changing lameness status if scored as being nonlame (NRS <3) on at least 1 of the 4 visits. Cows classified as having a changing lameness status were further classified as developed, recovered, or inconsistent. Lying behavior (daily lying time, mean lying bout duration, and daily number of lying bouts) was recorded continuously for 3 wk using leg-mounted accelerometers. Cow-level variables included parity, days in milk, and body condition score. Regional precipitation and temperature were recorded hourly. Because only 1 primiparous cow was identified as lame at each of the 4 visits, the between-cow analysis of lameness was run on multiparous cows only. The overall prevalence of clinical lameness on the first visit was 39%, with development and recovery rates of 16 and 10% over the 4 visits, respectively. The between-cow effect of consistent lameness status on daily lying time and number of lying bouts was dependent on precipitation; consistently lame cows had reduced lying time and lying bouts on days with rain compared with days without rain. There was no within-cow effect of changing lameness status on any of the lying behaviors. Precipitation was associated with decreased daily lying time, increased mean lying bout duration, and decreased daily number of lying bouts. The results of this research provide the first evidence that the effect of consistent lameness status on lying behavior is associated with rainfall in grazing dairy cows. Future work measuring lying behavior of grazing dairy cows should include precipitation as a covariate.

Prediction of blood β-hydroxybutyrate content and occurrence of hyperketonemia in early-lactation, pasture-grazed dairy cows using milk infrared spectra Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): V. Bonfatti, S-A. Turner, B. Kuhn-Sherlock, T.D.W. Luke, P.N. Ho, C.V.C. Phyn, J.E. Pryce ABSTRACT The objective of this study was to evaluate the ability of milk infrared spectra to predict blood β-hydroxybutyrate (BHB) concentration for use as a management tool for cow metabolic health on pasture-grazed dairy farms and for large-scale phenotyping for genetic evaluation purposes. The study involved 542 cows (Holstein-Friesian and Holstein-Friesian × Jersey crossbreds), from 2 farms located in the Waikato and Taranaki regions of New Zealand that operated under a seasonal-calving, pasture-based dairy system. Milk infrared spectra were collected once a week during the first 5 wk of lactation. A blood "prick" sample was taken from the ventral labial vein of each cow 3 times a week for the first 5 wk of lactation. The content of BHB in blood was measured immediately using a handheld device. After outlier elimination, 1,910 spectra records and corresponding BHB measures were used for prediction model development. Partial least square regression and partial least squares discriminant analysis were used to develop prediction models for quantitative determination of blood BHB content and for identifying cows with hyperketonemia (HYK). Both quantitative and discriminant predictions were developed using the phenotypes and infrared spectra from two-thirds of the cows (randomly assigned to the calibration set) and tested using the remaining one-third (validation set). A moderate accuracy was obtained for prediction of blood BHB. The coefficient of determination (R2) of the prediction model in calibration was 0.56, with a root mean squared error of prediction of 0.28 mmol/L and a ratio of performance to deviation, calculated as the ratio of the standard deviation of the partial least squares model calibration set to the standard error of prediction, of 1.50. In the validation set, the R2 was 0.50, with root mean squared error of prediction values of 0.32 mmol/L, which resulted in a ratio of performance to deviation of 1.39. When the reference test for HYK was defined as blood concentration of BHB ≥1.2 mmol/L, discriminant models indicated that milk infrared spectra correctly classified 76% of the HYK-positive cows and 82% of the HYK-negative cows. The quantitative models were not able to provide accurate estimates, but they could differentiate between high and low BHB concentrations. Furthermore, the discriminant models allowed the classification of cows with reasonable accuracy. This study indicates that the prediction of blood BHB content or occurrence of HYK from milk spectra is possible with moderate accuracy in pasture-grazed cows and could be used during routine milk testing. Applicability of infrared spectroscopy is not likely suited for obtaining accurate BHB measurements at an individual cow level, but discriminant models might be used in the future as herd-level management tools for classification of cows that are at risk of HYK, whereas quantitative models might provide large-scale phenotypes to be used as an indicator trait for breeding cows with improved metabolic health.

Effect of weaning age on growth, mammary gland development, and immune function in Holstein Friesian calves fed conserved alfalfa (FiberStart) Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): S. McCoard, A. Heiser, K. Lowe, A. Molenaar, P. MacLean, P. Johnstone, S. Leath, S.O. Hoskin, M.A. Khan ABSTRACT This study aimed to evaluate intake, body growth, and the development of the rumen, mammary gland, and immune system in Holstein Friesian calves reared for 100 d on the commercially available feed FiberStart (conserved alfalfa, Medicago sativa; Fiber Fresh Feeds Ltd., Reporoa, New Zealand) and fed calf milk replacer (CMR) for either 56 or 91 d. Eighty calves (40 bulls and 40 heifer calves) were reared indoors in groups (n = 5 of the same sex/pen). All calves were fed 4 L of CMR/d (175 g/L of CMR) in 2 feeds/d for the first 10 d and then 1 feed/d until d 49 or 84. The calves were gradually weaned by d 56 (earlier weaned; n = 8 pens) and d 91 (later weaned; n = 8 pens). All calves were fed FiberStart ad libitum as the only solid feed source from d 1 to 100 of the study. Irrespective of treatment, all calves had similar body weights at d 0 (40.9 ± 3.0 kg) and d 49 (74.2 ± 5.1 kg) of the study. Calf sex had no effect on intake, growth, blood, and immune system parameters. Earlier-weaned calves consumed 18% more solid feed dry matter but had 16% lower body weight gain (28.9 vs. 38.5 kg, respectively) from d 56 to 100 relative to later-weaned calves, resulting in different body weight at 100 d (104 vs. 121 ± 1.3 kg). Although earlier-weaned calves could compensate for the loss of CMR dry matter and crude protein intake from d 56 to 100 by increasing forage intake, they were unable to compensate for the loss of energy from the CMR by increasing solid feed consumption. Plasma β-hydroxybutyrate concentrations were 52% greater in earlier-weaned calves than in later-weaned calves at d 84, indicating greater metabolic activity of the rumen wall. The duration of CMR feeding had no influence on humoral or cell-mediated immune functions of the calves, as evidenced by a lack of effect on antivaccine antibody responses as well as on immune gene expression. Earlier- versus later-weaned heifer calves had 5% lower mammary gland mass, indicating that greater energy supply increased mammary mass. The results of this experiment demonstrate the ability to artificially rear dairy calves on a conserved alfalfa as the only solid feed. Furthermore, earlier weaning off CMR promotes solid feed intake and an associated increase in blood β-hydroxybutyrate, an indicator of rumen development, but increasing the duration of CMR feeding improves growth and mammary gland mass by d 100. The implications of these findings on lifetime growth, health, and milk production in dairy heifers warrant further investigation.

Invited review: A systematic review of the effects of early separation on dairy cow and calf health Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): Annabelle Beaver, Rebecca K. Meagher, Marina A.G. von Keyserlingk, Daniel M. Weary ABSTRACT Concern from the public is growing regarding early cow-calf separation, yet proponents of this practice maintain that artificial rearing is critical for cow and calf health. Early separation is assumed to reduce the risk of transfer of pathogens from dam to neonatal calf, but a wide range of health benefits associated with extended cow-calf contact has also been documented. The aim of this systematic review was to report and synthesize conclusions from the literature on dairy cow and calf health in conventional rearing versus cow-calf contact systems. Peer-reviewed, published manuscripts, written in English, directly comparing dairy cow or calf health in artificial versus suckling systems, were eligible for inclusion. We conducted 7 targeted searches using Web of Science to identify key literature on important health conditions. The resulting manuscripts underwent a 4-step appraisal process, and further manuscripts were sourced from reference lists. This process resulted in a final sample of 70 articles that addressed cow and calf health. Sufficient literature was available to assess mastitis in cows, and scours, cryptosporidiosis, Johne's disease, pneumonia, immunity, and mortality in calves. The results for cryptosporidiosis, pneumonia, immunity, and mortality were mixed, with some differences between studies likely attributable to flawed comparisons between cohorts. Overall, the articles addressing calf scours and mastitis pointed to beneficial or no effects of suckling. The studies addressing Johne's disease did not find cow-calf contact to be a significant risk factor. In conclusion, the scientific peer-reviewed literature on cow and calf health provides no consistent evidence in support of early separation.

Effects of blends of camel and calf chymosin on proteolysis, residual coagulant activity, microstructure, and sensory characteristics of Beyaz peynir Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): P. Gumus, A.A. Hayaloglu ABSTRACT Beyaz peynir, white-brined cheese, was manufactured using different blends of camel chymosin (100, 75, 50, 25, and 0%) with calf chymosin and ripened for 90 d. The purpose of this study was to determine the best mixture of coagulant for Beyaz peynir, in terms of the level of proteolysis, texture, and melting characteristic. The cheeses were evaluated in terms of chemical composition, levels of proteolysis, total free amino acids, texture, meltability, residual coagulant activity, microstructure, and sensory properties during 90 d of ripening. Differences in the gross chemical composition of these cheeses were statistically significant for all types of cheeses. We found that the levels of proteolysis were highly dependent on the blends of the coagulants. The higher proteolysis was observed in the cheeses using a higher ratio of calf chymosin. The differences of urea-PAGE and peptide profiles of each cheese were observed as well. Meltability values proportionally increased with the higher increasing levels of calf chymosin in the blend formula. These coagulants had a slight effect on the microstructure of cheeses. The cheese made with camel chymosin produced a harder texture than calf chymosin cheese, and hardness values of all cheese samples decreased during ripening. The cheeses having a high ratio of calf chymosin had higher residual enzyme activity than the cheeses made with camel chymosin. No significant difference in sensory properties was observed among the cheeses. In conclusion, the cheeses made with a high level of calf chymosin provided a higher level of proteolysis, residual coagulant activity, and meltability. The cheeses also presented a softer texture than cheeses made with a high content of camel chymosin. It was also found that camel chymosin may be used as a coagulant alone if low or limited levels of proteolysis are desired in the cheese.

Intravenous calcium infusion in a calving protocol disrupts calcium homeostasis compared with an oral calcium supplement Publication date: Available online 10 May 2019 Source: Journal of Dairy Science Author(s): Juliette Wilms, Guanlin Wang, John Doelman, Marc Jacobs, Javier Martín-Tereso ABSTRACT Hypocalcemia is a common postpartum condition in dairy cows, which negatively affects health and production. Intravenous Ca infusions are commonly included in calving protocols to prevent or mitigate the effect of hypocalcemia in multiparous cows. Thus, we sought to contrast the effect of intravenous Ca infusion against voluntary oral Ca intake on Ca metabolism. Serum total Ca (tCa) and whole-blood ionized Ca (iCa) were monitored in 24 multiparous Holstein cows after parturition. Precalving diets were formulated with a positive dietary cation-anion difference of 172 mEq/kg of DM and contained 4.1 g of Ca/kg of DM. At parturition, cows were blocked by calving sequence and calcemic status as either normocalcemic (cutoff threshold of iCa ≥1.10 mmol/L) or hypocalcemic (cutoff threshold of iCa <1.10 mmol/L). Cows in each block were randomly assigned to 1 of 2 treatments: either an oral source of Ca (Ca-Oral; n = 12) or an intravenous source of Ca (Ca-IV; n = 12). Cows in the Ca-Oral group were offered a 20-L commercial Ca suspension (48 g of Ca) for voluntary consumption. The supplement contained Ca carbonate, Ca formate, Ca propionate, and other minerals and vitamins (Farm-O-San Reviva, Trouw Nutrition, Amersfoort, the Netherlands). Cows in the Ca-IV group received a 450-mL intravenous Ca solution (13 g of Ca) that contained 298 mg/mL of Ca gluconate, 33 mg/mL of magnesium chloride, and 82 mg/mL of boric acid (AmosCAL, Kommer-Biopharm BV, Heiloo, the Netherlands). Both treatments were initiated within 25 ± 10 min after calving. The oral Ca suspension was offered to cows in a 25-L bucket and was available for 10 min. All cows in the Ca-Oral group voluntarily consumed the entire 20 L of the Ca suspension within 5 min. Blood samples for Ca analyses were collected at 0 (before treatment initiation), 1, 3, 10, and 18 h relative to treatment, and at 0700 and 1900 h for the next 2 consecutive days, to represent the 24-, 36-, 48-, and 60-h sampling time points. In Ca-IV cows, both iCa and tCa concentrations peaked at 1 h (1.54 mmol/L for iCa and 2.85 mmol/L for tCa) and declined to a nadir at 24 h following treatment initiation (0.94 mmol/L for iCa and 1.74 mmol/L for tCa). Although whole-blood iCa and serum tCa were higher at 1 and 3 h in Ca-IV cows, concentrations of iCa were greater for Ca-Oral cows at 18, 24, and 36 h and for tCa at 24 and 36 h. Our data indicate that intravenous Ca infusion immediately induced a state of hypercalcemia followed by lower whole-blood iCa and serum tCa concentrations 24 h later compared with oral Ca.

Genetics

Is Gcn4-induced autophagy the ultimate downstream mechanism by which hormesis extends yeast replicative lifespan? Abstract The number of times a cell divides before irreversibly arresting is termed replicative lifespan. Despite discovery of many chemical, dietary and genetic interventions that extend replicative lifespan, usually first discovered in budding yeast and subsequently shown to apply to metazoans, there is still little understanding of the underlying molecular mechanisms involved. One unifying theme is that most, if not all, interventions that extend replicative lifespan induce "hormesis", where a little inflicted damage makes cells more able to resist similar challenges in the future. One of the many cellular changes that occur during hormesis is a global reduction in protein synthesis, which has been linked to enhanced longevity in many organisms. Our recent study in budding yeast found that it was not the reduction in protein synthesis per se, but rather the subsequent induction of the conserved Gcn4 transcriptional regulator and its ability to induce autophagy that was responsible for extending replicative lifespan. We propose that Gcn4-dependent induction of autophagy occurring downstream of reduced global protein synthesis may be a unifying molecular mechanism for many interventions that extend replicative lifespan.

More than just a phase: the search for membraneless organelles in the bacterial cytoplasm Abstract The bacterial cytoplasm, once thought to be a relatively undifferentiated reaction medium, has now been recognized to have extensive microstructure. This microstructure includes bacterial microcompartments, inclusion bodies, granules, and even some membrane-bound vesicles. Several recent papers suggest that bacteria may also organize their cytoplasm using an additional mechanism: phase-separated membraneless organelles, a strategy commonly used by eukaryotes. Phase-separated membraneless organelles such as Cajal bodies, the nucleolus, and stress granules allow proteins to become concentrated in sub-compartments of eukaryotic cells without being surrounded by a barrier to diffusion. In this review, we summarize the known structural organization of the bacterial cytoplasm and discuss the recent evidence that phase-separated membraneless organelles might also play a role in bacterial systems. We specifically focus on bacterial ribonucleoprotein complexes and two different protein components of the bacterial nucleoid that may have the ability to form subcellular partitions within bacteria cells.

Linking the organization of DNA replication with genome maintenance Abstract The spatial and temporal organization of genome duplication, also referred to as the replication program, is defined by the distribution and the activities of the sites of replication initiation across the genome. Alterations to the replication profile are associated with cell fate changes during development and in pathologies, but the importance of undergoing S phase with distinct and specific programs remains largely unexplored. We have recently addressed this question, focusing on the interplay between the replication program and genome maintenance. In particular, we demonstrated that when cells encounter challenges to DNA synthesis, the organization of DNA replication drives the response to replication stress that is mediated by the ATR/Rad3 checkpoint pathway, thus shaping the pattern of genome instability along the chromosomes. In this review, we present the major findings of our study and discuss how they may bring new perspectives to our understanding of the biological importance of the replication program.

Role of Mediator in virulence and antifungal drug resistance in pathogenic fungi Abstract Mediator complex has recently emerged as an important regulator of gene expression in pathogenic fungi. Mediator is a multi-subunit complex of polypeptides involved in transcriptional activation in eukaryotes, with roles including preinitiation complex (PIC) assembly and chromatin remodeling. Within the last decade, Mediator has been shown to play an integral role in regulating virulence gene expression and drug resistance in human fungal pathogens. In some fungi, specific Mediator subunits have been shown to be required for virulence. In Candida species, duplication and expansion of Mediator subunit encoding genes has occurred on at least three occasions (CgMED15 in C. glabrata and MED2/TLO in C. albicans and C. dubliniensis) suggesting important roles for Mediator in the evolution of these pathogens. This review summarises recent developments in our understanding of Mediator in fungal pathogens and the potential for the development of therapeutic drugs to target Mediator functions.

Disturbance in biosynthesis of arachidonic acid impairs the sexual development of the onion blight pathogen Stemphylium eturmiunum Abstract The formation of sexual fruiting bodies for plant pathogenic fungi is a key strategy to propagate their progenies upon environmental stresses. Stemphylium eturmiunum is an opportunistic plant pathogen fungus causing blight in onion. This self-fertilizing filamentous ascomycete persists in the soil by forming pseudothecia, the sexual fruiting body which helps the fungus survive in harsh environments. However, the regulatory mechanism of pseudothecial formation remains unknown. To uncover the mechanism for pseudothecial formation so as to find a practical measure to control the propagation of this onion pathogen, we tentatively used DNA methyltransferase inhibitor 5-azacytidine (5-AC) to treat S. eturmiunum. 5-AC treatment silenced the gene-encoding monoacylglycerol lipase (magl) concomitant with the presence of the inheritable fluffy phenotype and defectiveness in pseudothecial development. Moreover, the silence of magl also resulted in a reduction of arachidonic acid (AA) formation from 27 ± 3.1 µg/g to 9.5 ± 1.5 µg/g. To correlate the biosynthesis of AA and pseudothecial formation, we created magl knockdown and overexpression strains. Knockdown of magl reduced AA to 11 ± 2.4 µg/g, which subsequently disabled pseudothecial formation. In parallel, overexpression of maglincreased AA to 37 ± 3.4 µg/g, which also impaired pseudothecial formation. Furthermore, exogenous addition of AA to the culture of magl-silenced or magl knockdown strains rescued the pseudothecial formation but failed in the gpr1 knockdown strain of S. eturmiunum, which implicates the involvement of AA in signal transduction via a putative G protein-coupled receptor 1. Thus, AA at a cellular level of 27 ± 3.1 µg/g is essential for sexual development of S. eturmiunum. Disturbance in the biosynthesis of AA by up- and down-regulating the expression of magl disables the pseudothecial development. The specific requirement for AA in pseudothecial development by S. eturmiunum provides a hint to curb this onion pathogen: to impede pseudothecial formation by application of AA.

Synergy of Hir1, Ssn6, and Snf2 global regulators is the functional determinant of a Mac1 transcriptional switch in S. cerevisiae copper homeostasis Abstract To gain insights on the transcriptional switches that modulate proper copper homeostasis in yeast, we have examined in detail functional interactions of the relevant transcriptional activator Mac1. We identified Hir1 transcriptional repressor and histone chaperone as a Mac1-interacting protein. This association directly recruits Hir1 on a Mac1 target, CTR1 promoter, quantitatively under induction conditions. We also found Hir1 interacting directly with a previously unknown partner, the Ssn6 (Cyc8) co-regulator. On the non-induced CTR1 promoter, a Hir1 transcriptional activation function was revealed, in the absence of Ssn6, which was dependent on the presence of Snf2 (Swi2) nucleosome remodeler. Moreover, Ssn6 was identified as a Mac1-dependent prominent repressor of CTR1 transcription, antagonizing Snf2 occupancy. Transcriptional induction by copper depletion was effected by the quantitative recruitment of Snf2 directed mainly by Mac1 and redundantly by the quantitatively accumulated Hir1 and Ssn6 pair. Our analysis showed that the activation-effecting chromatin remodeling of CTR1 was due to Snf2 and not to the Hir1 histone chaperone activity or ability to regulate histone levels and stoichiometry. Following initiation, Hir1 and Snf2, but not Ssn6, were found to associate also with the actively transcribing CTR1 coding region, where Hir1 followed the pattern of the elongating RNA polymerase II. Therefore, we have shown that, at the CTR1 gene, in association with Mac1 DNA-binding transcriptional activator, the distinct and alternate genetic and physical collaboration of three global regulators modulates the transcriptional state of a switch involved in copper homeostasis.

Versatility of the Mec1 ATM/ATR signaling network in mediating resistance to replication, genotoxic, and proteotoxic stresses Abstract The ataxia-telangiectasia mutated/ATM and Rad3-related (ATM/ATR) family proteins are evolutionarily conserved serine/threonine kinases best known for their roles in mediating the DNA damage response. Upon activation, ATM/ATR phosphorylate numerous targets to stabilize stalled replication forks, repair damaged DNA, and inhibit cell cycle progression to ensure survival of the cell and safeguard integrity of the genome. Intriguingly, separation of function alleles of the human ATM and MEC1, the budding yeast ATM/ATR, were shown to confer widespread protein aggregation and acute sensitivity to different types of proteotoxic agents including heavy metal, amino acid analogue, and an aggregation-prone peptide derived from the Huntington's disease protein. Further analyses unveiled that ATM and Mec1 promote resistance to perturbation in protein homeostasis via a mechanism distinct from the DNA damage response. In this minireview, we summarize the key findings and discuss ATM/ATR as a multifaceted signalling protein capable of mediating cellular response to both DNA and protein damage.

On the duration of the microbial lag phase Abstract When faced with environmental changes, microbes enter a lag phase during which cell growth is arrested, allowing cells to adapt to the new situation. The discovery of the lag phase started the field of gene regulation and led to the unraveling of underlying mechanisms. However, the factors determining the exact duration and dynamics of the lag phase remain largely elusive. Naively, one would expect that cells adapt as quickly as possible, so they can resume growth and compete with other organisms. However, recent studies show that the lag phase can last from several hours up to several days. Moreover, some cells within the same population take much longer than others, despite being genetically identical. In addition, the lag phase duration is also influenced by the past, with recent exposure to a given environment leading to a quicker adaptation when that environment returns. Genome-wide screens in Saccharomyces cerevisiae on carbon source shifts now suggest that the length of the lag phase, the heterogeneity in lag times of individual cells, and the history-dependent behavior are not determined by the time it takes to induce a few specific genes related to uptake and metabolism of a new carbon source. Instead, a major shift in general metabolism, and in particular a switch between fermentation and respiration, is the major bottleneck that determines lag duration. This suggests that there may be a fitness trade-off between complete adaptation of a cell's metabolism to a given environment, and a short lag phase when the environment changes.

SET domains and stress: uncovering new functions for yeast Set4 Abstract Chromatin dynamics are central to the regulation of gene expression and genome stability, particularly in the presence of environmental signals or stresses that prompt rapid reprogramming of the genome to promote survival or differentiation. While numerous chromatin regulators have been implicated in modulating cellular responses to stress, gaps in our mechanistic understanding of chromatin-based changes during stress suggest that additional proteins are likely critical to these responses and the molecular details underlying their activities are unclear in many cases. We recently identified a role for the relatively uncharacterized SET domain protein Set4 in promoting cell survival during oxidative stress in Saccharomyces cerevisiae. Set4 is a member of the Set3 subfamily of SET domain proteins which are defined by the presence of a PHD finger and divergent SET domain sequences. Here, we integrate our new observations on the function of Set4 with known roles for other related family members, including yeast Set3, fly UpSET and mammalian proteins MLL5 and SETD5. We discuss outstanding questions regarding the molecular mechanisms by which these proteins control gene expression and their potential contributions to cellular responses to environmental stress.

Quiescence, an individual journey Abstract Quiescence is operationally characterized as a temporary and reversible proliferation arrest. There are many preconceived ideas about quiescence, quiescent cells being generally viewed as insignificant sleeping G1 cells. In fact, quiescence is central for organism physiology and its dysregulation involved in many pathologies. The quiescent state encompasses very diverse cellular situations depending on the cell type and its environment. This diversity challenges not only quiescence uniformity but also the universality of the molecular mechanisms beyond quiescence regulation. In this mini-perspective, we discuss recent advances in the concept of quiescence, and illustrate that this multifaceted cellular state is gaining increasing attention in many fields of biology.