Anaerobic carbon monoxide metabolism by Pleomorphomonas carboxyditropha sp. nov., a new mesophilic hydrogenogenic carboxydotroph

Abstract

Carbon monoxide (CO)-metabolism and phenotypic and phylogenetic characterization of a novel anaerobic, mesophilic and hydrogenogenic carboxydotroph are reported. Strain SVCO-16 was isolated from anaerobic sludge and grows autotrophically and mixotrophically with CO. The genes cooS and cooF, coding for a CO dehydrogenase complex, and genes similar to hycE2, encoding a CO-induced hydrogenase, were present in its genome. The isolate produces H₂ and CO₂ from CO, and acetate and formate from organic substrates. Based on the 16S rRNA sequence, it is an Alphaproteobacterium most closely related to the genus Pleomorphomonas (98.9%–99.2% sequence identity). Comparison with other previously characterized Pleomorphomonas showed that P. diazotrophica and P. oryzae do not metabolize CO, and P. diazotrophica does not grow anaerobically with organic substrates. Average nucleotide identity values between strain SVCO-16 and P. diazotrophica, P. oryzae or P. koreensis were 86.66 ± 0.21%. These values are below the boundary to define species (95%–96%). Digital DNA-DNA hybridization estimates between strain SVCO-16 and reference strains were also below the 70% threshold for species delineation: 29.1%–34.5%. Based on the differences in CO metabolism, genome analyses and cellular fatty acid composition, the isolate should be classified into the genus Pleomorphomonas as a representative of a novel species, Pleomorphomonas carboxyditropha. The type strain of Pleomorphomonas carboxyditropha is SVCO-16^T (strain deposit numbers, DSM 106132^T and TSD-119^T).

https://ift.tt/2KFIPAu

Comparing rock-inhabiting microbial communities in different rock types from a high arctic polar desert

Abstract

Although rocks are habitable places for microbes in extreme environments, microbial diversity in these lithic environments is still poorly understood. The diversity and abundance of rock-inhabiting microbial communities in different types of rock in Svalbard, Norwegian High Arctic were examined using NGS sequencing of bacterial 16S rRNA genes and fungal 28S rRNA genes. Compositions of both bacterial and fungal communities varied across different rock types: sandstone, limestone, basalt, granite and travertine. Bacterial communities were dominated by Actinobacteria, Proteobacteria, Chloroflexi, Bacteroidetes and Acidobacteria. Fungal communities consisted of Eurotiomycetes, Lecanoromycetes, Dothideomycetes and Leotiomycetes. Both bacterial and fungal community compositions were significantly correlated with the geochemical characteristics of rocks. Bacterial communities were considerably correlated with the rock elements such as Mg and Ca. Fungal communities were considerably correlated with Fe. Interestingly, many dominant bacterial and fungal operational taxonomic units in the investigated rocks from the study area were closely affiliated to those found in other cold regions such as Alpine area, Arctic and Antarctica, suggesting that environmental constraints such as cold temperature may lead to convergence in microbial community composition. These results confirm that rocks in cold environments act as reservoirs of diverse bacteria and fungi, which may improve our understanding of lithic microbial ecology in the cold desert.

https://ift.tt/2rlj1kj

The sensory origin of the sense of effort is context-dependent

Abstract

The origin of the sense of effort has been debated for several decades and there is still no consensus among researchers regarding the underlying neural mechanisms. Some advocate that effort perception mainly arises from an efference copy originating within the brain while others believe that it is predominantly carried by muscle afferent signals. To move the debate forward, we here tested the hypothesis that there is not one but several senses of effort which depend on the way it is evaluated. For this purpose, we used two different psychophysical tests designed to test effort perception in elbow flexors. One was a bilateral isometric force-matching task in which subjects were asked to direct similar amounts of effort toward their two arms, while the other consisted of a unilateral voluntary isometric contraction in which subjects had to rate their perceived effort using a Borg scale. Throughout two distinct experiments, effort perception was evaluated before and following different tendon vibration protocols intended to differentially desensitize muscle spindles and Golgi tendon organs, and to affect the gain between the central effort and muscle contraction intensity. By putting all the results together, we found that spindle afferents played divergent roles across tasks. Namely, while they only acted as modulators of motor pathway excitability during the bilateral task, they clearly intervened as the predominant psychobiological signal of effort perception during the unilateral task. Therefore, the sensory origin of the sense of effort is not central or peripheral. Rather, it is context-dependent.

https://ift.tt/2IgwILy

Unilateral wrist extension training after stroke improves strength and neural plasticity in both arms

Abstract

Stroke induces bilateral neurological impairment and muscle weakness yielding neurologically more (MA; paretic) and less affected (LA; non-paretic) sides. "Cross-education" refers to training one side of the body to increase strength in the same muscles on the untrained side. Past work showed dorsiflexion training of the LA side produced bilateral strength increases after stroke. The current study explored the presence and extent of cross-education after arm strength training in chronic stroke. Twenty-four chronic stroke participants completed 5 weeks of maximal wrist extension training using their LA arm. Maximal voluntary contraction force, arm motor impairment and functional performance were measured before and after training. Both spinal cord plasticity (n = 12: reciprocal inhibition and cutaneous reflexes, University of Victoria) and cortical plasticity (n = 12: cortical silent period, short-interval intracortical inhibition, intracortical facilitation and transcallosal inhibition, University of British Columbia) were assessed. Five weeks after training, 20 participants completed a follow-up maximal wrist extension retention test. LA wrist extension force increased 42% and MA by 35%. Strength gains were maintained in the follow-up test. Clinically meaningful increases in Fugl-Meyer scores were noted in four participants. Muscle activation was correlated with cutaneous reflex amplitudes after training in the MA arm. LA cortical silent period and transcallosal inhibition from both hemispheres significantly decreased after training. This study shows that high-intensity training with the neurologically less affected "non-paretic" arm can improve strength bilaterally and alter both spinal and cortical plasticity. The extent to which this plasticity can be enhanced or functionally exploited remains to be examined.

https://ift.tt/2roEiJA

Prospective Assessment of Linox Implantable Cardioverter Defibrillator Leads for Structural or Electrical Abnormalities

Abstract

Introduction

Insulation failure leading to conductor externalization (CE) of a Linox (Biotronik, Berlin, Germany) implantable cardioverter defibrillator (ICD) lead has recently been reported. The aim of this study was to assess prospectively all Linox family ICD leads implanted at our center for evidence of CE or an electrical abnormality.

Methods

All patients with a Linox family ICD lead implanted at our center, between November 2007 and March 2015, were identified and all living patients were invited to attend for fluoroscopic screening and electrical assessment of the lead.

Results

A total of 183 patients had a Linox family ICD lead implanted at our center. Of these, 5 patients (2.7%) had the lead extracted because of electrical failure and 2 of these leads had evidence of CE. Out of 158 living patients with a Linox family ICD lead, 111 patients attended for screening (mean age 63.1 years, 22.5% female). In this group of patients, no cases of CE or electrical abnormalities of the lead were identified.

Conclusion

In this study evaluating 183 patients with a Linox family ICD lead implanted at a single center, 5 leads (2.7%) were explanted because of electrical failure and 2 of these leads had evidence of CE. Prospective fluoroscopic assessment of 111 Linox family ICD leads, with a mean dwell time of 31.5 months, revealed no further cases of CE.

https://ift.tt/2JUMFnU

Frailty in Hematologic Malignancy

Abstract

Purpose of Review

Older adults with hematologic malignancy are a growing demographic. Estimating risk of chemotherapy toxicity based on age alone is an unreliable estimate of quality of life, functional capacity, or risk of treatment complications.

Recent Findings

Dedicated geriatric assessment tools can aid the clinician in identifying geriatric syndromes such as frailty, resulting in improved prognostication to decrease morbidity and mortality. Frailty is not synonymous with individual performance status and is dynamic.

Summary

Establishing the patient goals, values, and preferences is central to the consideration of malignant hematology decision process. Careful considerations of available data on the patient's prognosis based on estimated life expectancy, geriatric assessment data, and age-specific cancer mortality, with and without treatment, can reconcile the risks and benefits. Assessments of frailty can aid the clinical feasibility and burden of the treatment to the patient and family in the context of each patient's unique needs.

https://ift.tt/2rsaXOP

Effect of high dietary levels of α-tocopherol acetate on immune response of light and heavy weight male broiler breeders

Abstract

The objective of this study was to investigate the effect of overdosing dietary α-tocopherol acetate (α-TOH) on immune response of heavy weight roosters. A total of 60 roosters (Ross 308) of light (LW, n = 30) and heavy weight (HW, n = 30) were kept in individual cages. Roosters were randomly allotted to ten treatment groups in a 2 × 5 factorial design. Each group received a basal diet supplemented with graded levels of α-TOH (0, 100, 200, 300, 400 mg/kg diet) for 10 weeks (from 25 to 35 week of age). Blood samples were collected at the fifth and tenth weeks of the experiment. Afterwards, humoral immune system function was evaluated by sheep red blood cell (SRBC) hemagglutination assay (HA) (at 35 weeks of age) and hemagglutination inhibition (HI) tests including antibody response to Newcastle disease viruses (NDV) and avian influenza viruses (AIV) (at 30 and 35 weeks of age). Cell-mediated immune response was evaluated by the cutaneous basophil hypersensitivity (CBH) test. A positive linear relationship was observed between incremental levels of dietary α-TOH and both humoral and cell-mediated immunity (P ≤ 0.05), with the highest immune parameters recorded for dietary supplementation of 400 mg/kg α-TOH (P ≤ 0.05). The results showed that CBH was significantly higher in LW roosters in comparison with HW roosters (P ≤ 0.05). However, the interaction of BW and α-TOH doses did not have any significant effect on immune responses (P ≥ 0.05). In conclusion, dietary supplementation of α-TOH at higher levels (four times more than the strain nutrients recommendation) had beneficial effects on the immune response of both HW and LW male broiler breeders.

https://ift.tt/2rlfqm8