Piloting the Virtual PLAYshop Program: A Parent-Focused Physical Literacy Intervention for Early Childhood.

The PLAYshop program is a parent-focused physical literacy intervention for early childhood. This single-group mixed-methods pilot study aimed to explore the feasibility of virtually delivering and assessing the PLAYshop program. The virtual PLAYshop program included a virtual workshop, resources/basic equipment, and two booster emails (3-week and 6-week follow-up). Data on 34 preschool-aged children (3-5 years) and their parents from Edmonton and Victoria, Canada, were collected via an online questionnaire, virtual assessment session, and interview at single or multiple time points (baseline, post-workshop, 2-month follow-up). Intraclass correlation coefficients (ICCs), paired t-tests, repeated measures ANOVAs, and thematic analyses were conducted. Regarding feasibility, most parents (≥94%) were satisfied/extremely satisfied with the virtual workshop and planned to continue physical literacy activities post-workshop. The virtual assessment protocol for children's fundamental movement skills (FMS; overhand throw, underhand throw, horizontal jump, hop, one-leg balance) was feasible, with high completion rates (>90%) and reliable scoring (ICC = 0.79-0.99). For positive changes in potential outcomes, a medium effect size was observed for children's hopping skills (d = 0.54), and large effect sizes were observed for several parental outcomes (partial η2 = 0.20-0.54). The findings support the feasibility and potential positive outcomes of the virtual PLAYshop program. A larger randomized controlled efficacy trial is recommended.

Mechanical environment for in vitro cartilage tissue engineering assisted by in silico models.

Mechanobiological study of chondrogenic cells and multipotent stem cells for articular cartilage tissue engineering (CTE) has been widely explored. The mechanical stimulation in terms of wall shear stress, hydrostatic pressure and mechanical strain has been applied in CTE in vitro. It has been found that the mechanical stimulation at a certain range can accelerate the chondrogenesis and articular cartilage tissue regeneration. This review explicitly focuses on the study of the influence of the mechanical environment on proliferation and extracellular matrix production of chondrocytes in vitro for CTE. The multidisciplinary approaches used in previous studies and the need for in silico methods to be used in parallel with in vitro methods are also discussed. The information from this review is expected to direct facial CTE research, in which mechanobiology has not been widely explored yet.

Looking Into the Future: The Current and Future State of IR in Canada.

This review explores the priorities and future opportunities of interventional radiology in Canada.

Differential regulation of alternate promoter regions in Sox17 during endodermal and vascular endothelial development.

Sox17 gene expression is essential for both endothelial and endodermal cell differentiation. To better understand the genetic basis for the expression of multiple Sox17 mRNA forms, we identified and performed CRISPR/Cas9 mutagenesis of two evolutionarily conserved promoter regions (CRs). The deletion of the upstream and endothelial cell-specific CR1 caused only a modest increase in lympho-vasculogenesis likely via reduced Notch signaling downstream of SOX17. In contrast, the deletion of the downstream CR2 region, which functions in both endothelial and endodermal cells, impairs both vascular and endodermal development causing death by embryonic day 12.5. Analyses of 3D chromatin looping, transcription factor binding, histone modification, and chromatin accessibility data at the Sox17 locus and surrounding region further support differential regulation of the two promoters during the development.

The impact of altering participant MRI scanning position on back muscle volume measurements.

Objectives: Muscle volume may reflect both strength and functional capability and hence is a parameter often measured to assess the effect of various interventions. The aim of the current study was to determine the sensitivity of muscle volume calculations on participant postural position and hence gauge possible errors that may arise in longitudinal studies, especially those where an intervention leads to large muscle changes and potentially the degree of spinal curvature. Methods: Twenty healthy participants (22-49 years, 10 male and 10 female), were recruited and MRI images acquired with them lying in four different positions; neutral spine (P1), decreased lordosis (P2), increased lordosis (P3) and neutral spine repeated (P4). Images were analysed in Simpleware ScanIP, and lumbar muscle volume and Cobb's angle, as an indicator of spine curvature, determined. Results: After comparing volume determinations, no statistically significant differences were found for P1 - P2 and P1 - P4, whereas significant changes were determined for P2 - P3 and P1 - P3. P2 and P3 represent the two extremes of spinal curvature with a difference in Cobb's angle of 17°. However, the mean difference between volume determinations was only 29 cm3. These results suggest the differences in muscle volume determinations are generally greater with increasing differences in curvature between measurements, but that overall the effects are small. Conclusions: Thus, generally, spinal muscle volume determinations are robust in terms of participant positioning. Advances in knowledge: Differences in muscle volume calculations appear to become larger the greater the difference in spinal curvature between positions. Thus, spinal curvature should not have a major impact on the results of spinal muscle volume determinations following interventions in longitudinal studies.

The Liver X Receptor Is Selectively Modulated to Differentially Alter Female Mammary Metastasis-associated Myeloid Cells.

Dysregulation of cholesterol homeostasis is associated with many diseases such as cardiovascular disease and cancer. Liver X receptors (LXRs) are major upstream regulators of cholesterol homeostasis and are activated by endogenous cholesterol metabolites such as 27-hydroxycholesterol (27HC). LXRs and various LXR ligands such as 27HC have been described to influence several extra-hepatic biological systems. However, disparate reports of LXR function have emerged, especially with respect to immunology and cancer biology. This would suggest that, similar to steroid nuclear receptors, the LXRs can be selectively modulated by different ligands. Here, we use RNA-sequencing of macrophages and single-cell RNA-sequencing of immune cells from metastasis-bearing murine lungs to provide evidence that LXR satisfies the 2 principles of selective nuclear receptor modulation: (1) different LXR ligands result in overlapping but distinct gene expression profiles within the same cell type, and (2) the same LXR ligands differentially regulate gene expression in a highly context-specific manner, depending on the cell or tissue type. The concept that the LXRs can be selectively modulated provides the foundation for developing precision pharmacology LXR ligands that are tailored to promote those activities that are desirable (proimmune), but at the same time minimizing harmful side effects (such as elevated triglyceride levels).

Use of Topical Hemostatic Dressings in an Extended Field Care Model.

BACKGROUND: We sought to test whether Celox topical hemostatic dressing (Medtrade Products) would maintain hemostasis in extended use. METHODS: An anesthetized swine underwent bilateral arteriotomies and treatment with topical hemostatic dressings in line with the Kheirabadi method. The dressings were covered with standard field dressings, and these were visually inspected for bleeding every 2 hours until 8 hours, when the swine was euthanized. RESULTS: There was no evidence of rebleeding at any point up to and including 8 hours. The Celox dressings maintained hemostasis in extended use. CONCLUSION: Celox topical hemostatic dressing is effective for extended use and maintains hemostasis. It should be considered for use in situations in which evacuation and definitive care may be delayed.

A real-world feasibility study of the PLAYshop: a brief intervention to facilitate parent engagement in developing their child's physical literacy.

BACKGROUND: Development of physical literacy, defined as "the motivation, confidence, physical competence, knowledge and understanding to value and take responsibility for engagement in physical activities for life," can support children's physically active behaviors and consequent health benefits. Little research has explored interventions to improve children's physical literacy, although substantive evidence shows parents play a key role in children's physically active behaviors and development of fundamental movement skills. The purpose of this study was to explore the feasibility of a novel, physical literacy program (the PLAYshop) designed to build parents' self-efficacy to support their child's physical literacy. METHODS: A non-randomized, one-arm concurrent nested design was used. Thirty-five parents of young children (3-8 years of age) attended a 75-min workshop inclusive of interactive activities, educational messages, and the provision of resources focused on core physical literacy concepts. Pre- and post-workshop surveys used quantitative measures to assess parents' satisfaction, knowledge, confidence, and intention to adopt practices. Follow-up interviews qualitatively explored the implementation experiences of both parents and facilitators. Paired t tests and thematic analysis were undertaken. RESULTS: Of the 33 eligible parents, 23 completed both pre- and post-workshop surveys. Follow-up interviews were completed with 11 parents and four workshop facilitators. Parents' self-reported knowledge and confidence to support their child's physical literacy development significantly increased after PLAYshop participation. The majority of parents were satisfied with the workshop and motivated to apply learnings at home with their child. Workshop facilitators identified seven workshop strengths (e.g., workshop champions and skilled facilitators) and four challenges (e.g., recruitment and unfavorable spaces). Limitations include the lack of control group and recruitment challenges. CONCLUSIONS: The PLAYshop was perceived positively by parents and facilitators and appeared to improve parent self-efficacy and intention to promote physical literacy with their child. Recruitment and attendance were key implementation challenges. The findings from this real-world study support the preliminary feasibility of the PLAYshop intervention and highlight areas to improve the intervention and recruitment prior to efficacy testing in a more rigorous trial format.

A Pragmatic Feasibility Trial Examining the Effect of Job Embedded Professional Development on Teachers' Capacity to Provide Physical Literacy Enriched Physical Education in Elementary Schools.

A gap in physical literacy (PL) oriented professional development (PD) for generalist teachers exists and thus their capacity to develop PL and maximize student health is potentially limited. We explored the feasibility of a novel job-embedded professional development (JEPD) program (10 weeks) and its impact on teachers' capacity to deliver PL-enriched physical education (PE) and student PL. A pragmatic feasibility trial with mixed methods included quantitative measurements of teacher PL, knowledge and confidence (pre), and knowledge, confidence, satisfaction and intention (post), as well as self-reported change, to evaluate the impact on teacher capacity and practices. A pre-post comparison of student PL outcomes (motor skills using PLAYbasic, Sport for Life, Victoria, BC, Canada) during the JEPD and teacher implementation phase explored the impact on student PL. In total, 15/44 teachers participated in surveys and 11/44 completed interviews (87% female, mean age bracket = 25-44 years). Confidence to deliver PL enhancing PE increased significantly after JEPD (p < 0.0001). Teachers were highly satisfied with the JEPD (X = 4.67/5) and intended to change their practices (X = 4.09/5). At three months, teachers reported changes including enhanced lesson planning, increased activity variety (often from the JEPD), intentional skill development, student-focused discussions, introductory, transition, and closing activities, and more equipment adaptations. During JEPD, with the exception of throwing (p < 0.0001), children's (47% female, mean age = 7.9 (1.7)) change in running, jumping, kicking and balance walking backwards did not differ from usual practice (UP). During teacher implementation, motor skill competence regressed; confounding factors could not be ruled out. JEPD appears feasible and effective for changing teacher capacity to deliver PL and enhancing PE; however, post-JEPD teacher implementation and outcomes need further exploration.

Adherence to the Standards for Reporting of Diagnostic Accuracy (STARD) 2015 Guidelines in Acute Point-of-Care Ultrasound Research.

Importance: Incomplete reporting of diagnostic accuracy research impairs assessment of risk of bias and limits generalizability. Point-of-care ultrasound has become an important diagnostic tool for acute care physicians, but studies assessing its use are of varying methodological quality. Objective: To assess adherence to the Standards for Reporting of Diagnostic Accuracy (STARD) 2015 guidelines in the literature on acute care point-of-care ultrasound. Evidence Review: MEDLINE was searched to identify diagnostic accuracy studies assessing point-of-care ultrasound published in critical care, emergency medicine, or anesthesia journals from 2016 to 2019. Studies were evaluated for adherence to the STARD 2015 guidelines, with the following variables analyzed: journal, country, STARD citation, STARD-adopting journal, impact factor, patient population, use of supplemental material, and body region. Data analysis was performed in November 2019. Findings: Seventy-four studies were included in this systematic review for assessment. Overall adherence to STARD was moderate, with 66% (mean [SD], 19.7 [2.9] of 30 items) of STARD items reported. Items pertaining to imaging specifications, patient population, and readers of the index test were frequently reported (>66% of studies). Items pertaining to blinding of readers to clinical data and to the index or reference standard, analysis of heterogeneity, indeterminate and missing data, and time intervals between index and reference test were either moderately (33%-66%) or infrequently (<33%) reported. Studies in STARD-adopting journals (mean [SD], 20.5 [2.9] items in adopting journals vs 18.6 [2.3] items in nonadopting journals; P = .002) and studies citing STARD (mean [SD], 21.3 [0.9] items in citing studies vs 19.5 [2.9] items in nonciting studies; P = .01) reported more items. Variation by country and journal of publication were identified. No differences in STARD adherence were identified by body region imaged (mean [SD], abdominal, 20.0 [2.5] items; head and neck, 17.8 [1.6] items; musculoskeletal, 19.2 [3.1] items; thoracic, 20.2 [2.8] items; and other or procedural, 19.8 [2.7] items; P = .29), study design (mean [SD], prospective, 19.7 [2.9] items; retrospective, 19.7 [1.8] items; P > .99), patient population (mean [SD], pediatric, 20.0 [3.1] items; adult, 20.2 [2.7] items; mixed, 17.9 [1.9] items; P = .09), use of supplementary materials (mean [SD], yes, 19.2 [3.0] items; no, 19.7 [2.8] items; P = .91), or journal impact factor (mean [SD], higher impact factor, 20.3 [3.1] items; lower impact factor, 19.1 [2.4] items; P = .08). Conclusions and Relevance: Overall, the literature on acute care point-of-care ultrasound showed moderate adherence to the STARD 2015 guidelines, with more complete reporting found in studies citing STARD and those published in STARD-adopting journals. This study has established a current baseline for reporting; however, future studies are required to understand barriers to complete reporting and to develop strategies to mitigate them.

Non-targeted analysis of the particulate phase of heated tobacco product aerosol and cigarette mainstream tobacco smoke by thermal desorption comprehensive two-dimensional gas chromatography with dual flame ionisation and mass spectrometric detection.

An analytical methodology based on thermal desorption and comprehensive two-dimensional gas chromatography with dual time-of-flight mass spectrometry and flame ionization detection (TD-GC × GC-TOFMS/FID) has been developed for non-target analysis of volatile organic compounds (VOCs). The technique was optimised for the measurement of the VOC content of the particulate phase (PP) fraction of aerosols produced by a tobacco heating product (THP1.0) and 3R4F mainstream tobacco smoke (MTS). The method involves sampling the PP fraction on quartz wool packed in a sorbent tube directly connected to machine-puffing, followed by a dilution through a TD recollection procedure over Tenax/Sulficarb sorbent before TD-GC × GC-TOFMS/FID analysis. The comparison of the VOC content of the PP fraction of aerosols produced by THP1.0 and MTS highlighted the compositional difference between tobacco combustion (592 peaks) and tobacco heating process (160 peaks). Mass spectrometric signals were used for qualitative analyses based on linear retention indices, mass spectral matches, and GC × GC structured chromatograms, which collectively identified up to 90% of analytes detected in PP samples. FID signals were used for semi-quantitative analyses based on a chemical class external calibration method. The global chemical composition of PP samples showed that hydrocarbons, oxygenated, and nitrogen-containing compounds were fewer in number and much less abundant in THP1.0 PP. Overall, 93 compounds were common to the two sample types. Excepted for a few highly volatile compounds (mainly furan family) as well as glycerine and its acetate, analyte concentrations were higher in MTS PP.

Physiology, Metabolism, and Fossilization of Hot-Spring Filamentous Microbial Mats.

The evolutionarily ancient Aquificales bacterium Sulfurihydrogenibium spp. dominates filamentous microbial mat communities in shallow, fast-flowing, and dysoxic hot-spring drainage systems around the world. In the present study, field observations of these fettuccini-like microbial mats at Mammoth Hot Springs in Yellowstone National Park are integrated with geology, geochemistry, hydrology, microscopy, and multi-omic molecular biology analyses. Strategic sampling of living filamentous mats along with the hot-spring CaCO3 (travertine) in which they are actively being entombed and fossilized has permitted the first direct linkage of Sulfurihydrogenibium spp. physiology and metabolism with the formation of distinct travertine streamer microbial biomarkers. Results indicate that, during chemoautotrophy and CO2 carbon fixation, the 87-98% Sulfurihydrogenibium-dominated mats utilize chaperons to facilitate enzyme stability and function. High-abundance transcripts and proteins for type IV pili and extracellular polymeric substances (EPSs) are consistent with their strong mucus-rich filaments tens of centimeters long that withstand hydrodynamic shear as they become encrusted by more than 5 mm of travertine per day. Their primary energy source is the oxidation of reduced sulfur (e.g., sulfide, sulfur, or thiosulfate) and the simultaneous uptake of extremely low concentrations of dissolved O2 facilitated by bd-type cytochromes. The formation of elevated travertine ridges permits the Sulfurihydrogenibium-dominated mats to create a shallow platform from which to access low levels of dissolved oxygen at the virtual exclusion of other microorganisms. These ridged travertine streamer microbial biomarkers are well preserved and create a robust fossil record of microbial physiological and metabolic activities in modern and ancient hot-spring ecosystems.

Genome of 'Charleston Gray', the principal American watermelon cultivar, and genetic characterization of 1,365 accessions in the U.S. National Plant Germplasm System watermelon collection.

Years of selection for desirable fruit quality traits in dessert watermelon (Citrullus lanatus) has resulted in a narrow genetic base in modern cultivars. Development of novel genomic and genetic resources offers great potential to expand genetic diversity and improve important traits in watermelon. Here, we report a high-quality genome sequence of watermelon cultivar 'Charleston Gray', a principal American dessert watermelon, to complement the existing reference genome from '97103', an East Asian cultivar. Comparative analyses between genomes of 'Charleston Gray' and '97103' revealed genomic variants that may underlie phenotypic differences between the two cultivars. We then genotyped 1365 watermelon plant introduction (PI) lines maintained at the U.S. National Plant Germplasm System using genotyping-by-sequencing (GBS). These PI lines were collected throughout the world and belong to three Citrullus species, C. lanatus, C. mucosospermus and C. amarus. Approximately 25 000 high-quality single nucleotide polymorphisms (SNPs) were derived from the GBS data using the 'Charleston Gray' genome as the reference. Population genomic analyses using these SNPs discovered a close relationship between C. lanatus and C. mucosospermus and identified four major groups in these two species correlated to their geographic locations. Citrullus amarus was found to have a distinct genetic makeup compared to C. lanatus and C. mucosospermus. The SNPs also enabled identification of genomic regions associated with important fruit quality and disease resistance traits through genome-wide association studies. The high-quality 'Charleston Gray' genome and the genotyping data of this large collection of watermelon accessions provide valuable resources for facilitating watermelon research, breeding and improvement.

Clostridium scindens ATCC 35704: Integration of Nutritional Requirements, the Complete Genome Sequence, and Global Transcriptional Responses to Bile Acids.

In the human gut, Clostridium scindens ATCC 35704 is a predominant bacterium and one of the major bile acid 7α-dehydroxylating anaerobes. While this organism is well-studied relative to bile acid metabolism, little is known about the basic nutrition and physiology of C. scindens ATCC 35704. To determine the amino acid and vitamin requirements of C. scindens, the leave-one-out (one amino acid group or vitamin) technique was used to eliminate the nonessential amino acids and vitamins. With this approach, the amino acid tryptophan and three vitamins (riboflavin, pantothenate, and pyridoxal) were found to be required for the growth of C. scindens In the newly developed defined medium, C. scindens fermented glucose mainly to ethanol, acetate, formate, and H2. The genome of C. scindens ATCC 35704 was completed through PacBio sequencing. Pathway analysis of the genome sequence coupled with transcriptome sequencing (RNA-Seq) under defined culture conditions revealed consistency with the growth requirements and end products of glucose metabolism. Induction with bile acids revealed complex and differential responses to cholic acid and deoxycholic acid, including the expression of potentially novel bile acid-inducible genes involved in cholic acid metabolism. Responses to toxic deoxycholic acid included expression of genes predicted to be involved in DNA repair, oxidative stress, cell wall maintenance/metabolism, chaperone synthesis, and downregulation of one-third of the genome. These analyses provide valuable insight into the overall biology of C. scindens which may be important in treatment of disease associated with increased colonic secondary bile acids.IMPORTANCEC. scindens is one of a few identified gut bacterial species capable of converting host cholic acid into disease-associated secondary bile acids such as deoxycholic acid. The current work represents an important advance in understanding the nutritional requirements and response to bile acids of the medically important human gut bacterium, C. scindens ATCC 35704. A defined medium has been developed which will further the understanding of bile acid metabolism in the context of growth substrates, cofactors, and other metabolites in the vertebrate gut. Analysis of the complete genome supports the nutritional requirements reported here. Genome-wide transcriptomic analysis of gene expression in the presence of cholic acid and deoxycholic acid provides a unique insight into the complex response of C. scindens ATCC 35704 to primary and secondary bile acids. Also revealed are genes with the potential to function in bile acid transport and metabolism.

Designing interoperable health information systems using Enterprise Architecture approach in resource-limited countries: A literature review.

BACKGROUND: Enterprise Architecture (EA) integrates business and technical processes in health information systems (HIS). Low-income and middle-income countries (LMIC) use EA to combine management components with disease tracking and health care service monitoring. Using an EA approach differs by country, addressing specific needs. METHODS: Articles in this review referenced EA, were peer-reviewed or gray literature reports published in 2010 to 2016 in English, and were identified using PubMed, Scopus, Web of Science, and Google Scholar. RESULTS: Fourteen articles described EA use in LMICs. India, Sierra Leone, South Africa, Mozambique, and Rwanda reported building the system to meet country needs and implement a cohesive HIS framework. Jordan and Taiwan focused on specific HIS aspects, ie, disease surveillance and electronic medical records. Five studies informed the context. The Millennium Villages Project employed a "uniform but contextualized" approach to guide systems in 10 countries; Malaysia, Indonesia, and Tanzania used interviews and mapping of existing components to improve HIS, and Namibia used of Activity Theory to identify technology-associated activities to better understand EA frameworks. South Africa, Burundi, Kenya, and Democratic Republic of Congo used EA to move from paper-based to electronic systems. CONCLUSIONS: Four themes emerged: the importance of multiple sectors and data sources, the need for interoperability, the ability to incorporate system flexibility, and the desirability of open group models, data standards, and software. Themes mapped to EA frameworks and operational components and to health system building blocks and goals. Most articles focused on processes rather than outcomes, as countries are engaged in implementation.

Comprehensive comparative compositional study of the vapour phase of cigarette mainstream tobacco smoke and tobacco heating product aerosol.

A simple direct sample collection/dilution and introduction method was developed using quartz wool and Tenax/sulficarb sorbents for thermal desorption and comprehensive two-dimensional gas chromatography (TD-GC × GC) analyses of volatile organic compounds from vapour phase (VP) fractions of aerosol produced by tobacco heating products (THP1.0) and 3R4F mainstream tobacco smoke (MTS). Analyses were carried out using flame ionisation detection (FID) for semi-quantification and both low and high resolution time-of-flight mass spectrometry (LR/HR-TOFMS) for qualitative comparison and peak assignment. Qualitative analysis was carried out by combining identification data based on linear retention indices (LRIs) with a match window of ±10 index units, mass spectral forward and reverse library searches (from LR and HRTOFMS spectra) with a match factor threshold of >700 (both forward and reverse), and accurate mass values of ± 3 ppm for increased confidence in peak identification. Using this comprehensive approach of data mining, a total of 79 out of 85 compounds and a total of 198 out of 202 compounds were identified in THP1.0 aerosol and in 3R4F MTS, respectively. Among the identified analytes, a set of 35 compounds was found in both VP sample types. Semi-quantitative analyses were carried out using a chemical class-based external calibration method. Acyclic, alicyclic, aromatic hydrocarbons and ketones appeared to be prominent in 3R4F MTS VP, whereas larger amounts of aldehydes, ketones, heterocyclic hydrocarbons and esters were present in THP1.0 aerosol VP. The results demontsrate the capability and versatility of the method for the characterization and comparison of complex aerosol samples and highlighted the relative chemical simplicity of THP1.0 aerosol in comparison to MTS.

Bile acid oxidation by Eggerthella lenta strains C592 and DSM 2243T.

Strains of Eggerthella lenta are capable of oxidation-reduction reactions capable of oxidizing and epimerizing bile acid hydroxyl groups. Several genes encoding these enzymes, known as hydroxysteroid dehydrogenases (HSDH) have yet to be identified. It is also uncertain whether the products of E. lenta bile acid metabolism are further metabolized by other members of the gut microbiota. We characterized a novel human fecal isolate identified as E. lenta strain C592. The complete genome of E. lenta strain C592 was sequenced and comparative genomics with the type strain (DSM 2243) revealed high conservation, but some notable differences. E. lenta strain C592 falls into group III, possessing 3α, 3ß, 7α, and 12α-hydroxysteroid dehydrogenase (HSDH) activity, as determined by mass spectrometry of thin layer chromatography (TLC) separated metabolites of primary and secondary bile acids. Incubation of E. lenta oxo-bile acid and iso-bile acid metabolites with whole-cells of the high-activity bile acid 7α-dehydroxylating bacterium, Clostridium scindens VPI 12708, resulted in minimal conversion of oxo-derivatives to lithocholic acid (LCA). Further, Iso-chenodeoxycholic acid (iso-CDCA; 3ß,7α-dihydroxy-5ß-cholan-24-oic acid) was not metabolized by C. scindens. We then located a gene encoding a novel 12α-HSDH in E. lenta DSM 2243, also encoded by strain C592, and the recombinant purified enzyme was characterized and substrate-specificity determined. Genomic analysis revealed genes encoding an Rnf complex (rnfABCDEG), an energy conserving hydrogenase (echABCDEF) complex, as well as what appears to be a complete Wood-Ljungdahl pathway. Our prediction that by changing the gas atmosphere from nitrogen to hydrogen, bile acid oxidation would be inhibited, was confirmed. These results suggest that E. lenta is an important bile acid metabolizing gut microbe and that the gas atmosphere may be an important and overlooked regulator of bile acid metabolism in the gut.