The Prevotellas comprise a diverse group of bacteria that has received surprisingly limited attention at the whole genome-sequencing level. In this communication, we present the comparative analysis ...of the genomes of Prevotella ruminicola 23 (GenBank: CP002006) and Prevotella bryantii B₁4 (GenBank: ADWO00000000), two gastrointestinal isolates. Both P. ruminicola and P. bryantii have acquired an extensive repertoire of glycoside hydrolases that are targeted towards non-cellulosic polysaccharides, especially GH43 bifunctional enzymes. Our analysis demonstrates the diversity of this genus. The results from these analyses highlight their role in the gastrointestinal tract, and provide a template for additional work on genetic characterization of these species.
From cellulosomes to cellulosomics Bayer, Edward A.; Lamed, Raphael; White, Bryan A. ...
Chemical record,
2008, 2008-00-00, 2008-01-00, 20080101, Letnik:
8, Številka:
6
Journal Article
The theoretical description of the forces that shape ecological communities focuses around two classes of models. In niche theory, deterministic interactions between species, individuals, and the ...environment are considered the dominant factor, whereas in neutral theory, stochastic forces, such as demographic noise, speciation, and immigration, are dominant. Species abundance distributions predicted by the two classes of theory are difficult to distinguish empirically, making it problematic to deduce ecological dynamics from typical measures of diversity and community structure. Here, we show that the fusion of species abundance data with genome-derived measures of evolutionary distance can provide a clear indication of ecological dynamics, capable of quantifying the relative roles played by niche and neutral forces. We apply this technique to six gastrointestinal microbiomes drawn from three different domesticated vertebrates, using high-resolution surveys of microbial species abundance obtained from carefully curated deep 16S rRNA hypervariable tag sequencing data. Although the species abundance patterns are seemingly well fit by the neutral theory of metacommunity assembly, we show that this theory cannot account for the evolutionary patterns in the genomic data; moreover, our analyses strongly suggest that these microbiomes have, in fact, been assembled through processes that involve a significant nonneutral (niche) contribution. Our results demonstrate that high-resolution genomics can remove the ambiguities of process inference inherent in classic ecological measures and permits quantification of the forces shaping complex microbial communities.
Summary
A cellulolytic fiber‐degrading bacterium, Ruminococcus champanellensis, was isolated from human faecal samples, and its genome was recently sequenced. Bioinformatic analysis of the R. ...champanellensis genome revealed numerous cohesin and dockerin modules, the basic elements of the cellulosome, and manual sequencing of partially sequenced genomic segments revealed two large tandem scaffoldin‐coding genes that form part of a gene cluster. Representative R. champanellensis dockerins were tested against putative cohesins, and the results revealed three different cohesin–dockerin binding profiles which implied two major types of cellulosome architectures: (i) an intricate cell‐bound system and (ii) a simplistic cell‐free system composed of a single cohesin‐containing scaffoldin. The cell‐bound system can adopt various enzymatic architectures, ranging from a single enzyme to a large enzymatic complex comprising up to 11 enzymes. The variety of cellulosomal components together with adaptor proteins may infer a very tight regulation of its components. The cellulosome system of the human gut bacterium R. champanellensis closely resembles that of the bovine rumen bacterium Ruminococcus flavefaciens. The two species contain orthologous gene clusters comprising fundamental components of cellulosome architecture. Since R. champanellensis is the only human colonic bacterium known to degrade crystalline cellulose, it may thus represent a keystone species in the human gut.
Forty percent of American women are obese and at risk for type II diabetes, impaired immune function, and altered microbiome diversity, thus impacting overall health. We investigated whether obesity ...induced by an excess calorie, high fat diet containing hydrogenated fats, fructose, and coconut oil (HFD) altered glucose homeostasis, peripheral immunity, and urogenital microbial dynamics. We hypothesized that HFD would cause hyperglycemia, increase peripheral inflammation, and alter urogenital microbiota to favor bacterial taxonomy associated with inflammation. We utilized female Ossabaw mini-pigs to model a 'thrifty' metabolic phenotype associated with increased white adipose tissue mass. Pigs were fed HFD (~4570 kcal/pig/day) or lean (~2000 kcal/pig/day) diet for a total of 9 estrous cycles (~6 months). To determine the effect of cycle stage on cytokines and the microbiome, animals had samples collected during cycles 7 and 9 on certain days of the cycle: D1, 4, 8, 12, 16, 18. Vaginal swabs or cervical flushes assessed urogenital microbiota. Systemic fatty acids, insulin, glucose, and cytokines were analyzed. Pig weights and morphometric measurements were taken weekly. Obese pigs had increased body weight, length, heart and belly girth but similar glucose concentrations. Obese pigs had decreased cytokine levels (IL-1β, TNF-α, IL-4, IL-10), arachidonic acid and plasma insulin, but increased levels of vaccenic acid. Obese pigs had greater urogenital bacterial diversity, including several taxa known for anti-inflammatory properties. Overall, induction of obesity did not induce inflammation but shifted the microbial communities within the urogenital tract to an anti-inflammatory phenotype. We postulate that the coconut oil in the HFD oil may have supported normal glucose homeostasis and modulated the immune response, possibly through regulation of microbial community dynamics and fatty acid metabolism. This animal model holds promise for the study of how different types of obesity and high fat diets may affect metabolism, immune phenotype, and microbial dynamics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The new complex Ru(pydppn)(biq)(py)(2+) (1) undergoes both py photodissociation in CH3CN with Φ500 =0.0070(4) and (1)O2 production with ΦΔ =0.75(7) in CH3 OH from a long-lived (3) ππ* state centered ...on the pydppn ligand (pydppn=3-(pyrid-2-yl)benzoidipyrido3,2-a:2',3'-cphenazine; biq = 2,2'-biquinoline; py=pyridine). This represents an order of magnitude decrease in the Φ500 compared to the previously reported model compound Ru(tpy)(biq)(py)(2+) (3) (tpy=2,2':6',2''-terpyridine) that undergoes only ligand exchange. The effect on the quantum yields by the addition of a second deactivation pathway through the low-lying (3) ππ* state necessary for dual reactivity was investigated using ultrafast and nanosecond transient absorption spectroscopy, revealing a significantly shorter (3) MLCT lifetime in 1 relative to that of the model complex 3. Due to the structural similarities between the two compounds, the lower values of Φ500 and ΦΔ compared to that of Ru(pydppn)(bpy)(py)(2+) (2) (bpy=2,2'-bipyridine) are attributed to a competitive excited state population between the (3) LF states involved in ligand dissociation and the long-lived (3) ππ* state in 1. Complex 1 represents a model compound for dual activity that may be applied to photochemotherapy.
Purpose
To summarise what is currently known about the psychosocial morbidity, experiences, and needs of people with cancer and their informal caregivers, who live in rural or regional areas of ...developed countries.
Methods
Eligible studies dating from August 2010 until May 2021 were identified through several online databases, including MEDLINE, EMBASE, PsychINFO, and RURAL (Rural and Remote Health Database). Results were reported according to the PRISMA guidelines and the protocol was registered on PROSPERO (CRD42020171764).
Results
Sixty-five studies were included in this review, including 20 qualitative studies, 41 quantitative studies, and 4 mixed methods studies. Qualitative research demonstrated that many unique psychosocial needs of rural people remain unmet, particularly relating to finances, travel, and accessing care. However, most (9/19) quantitative studies that compared rural and urban groups reported no significant differences in psychosocial needs, morbidity, or quality of life (QOL). Five quantitative studies reported poorer psychosocial outcomes (social and emotional functioning) in
urban
cancer survivors, while three highlighted poorer outcomes (physical functioning, role functioning, and self-reported mental health outcomes) in the rural group.
Conclusion
Recent research shows that rural people affected by cancer have unique unmet psychosocial needs relating to rurality. However, there was little evidence that rural cancer survivors report greater unmet needs than their urban counterparts. This contrasts to the findings from a 2011 systematic review that found rural survivors consistently reported worse psychosocial outcomes. More population-based research is needed to establish whether uniquely rural unmet needs are due to general or cancer-specific factors.
•Hydrogen sulfide production is increased in colorectal cancer (CRC) tumor samples.•Microbial community metabolic function is important to evaluate in CRC pathogenesis.•Synthesis of multi-omic data ...and metabolic models maximizes data potential.
Multi-omic data and genome-scale microbial metabolic models have allowed us to examine microbial communities, community function, and interactions in ways that were not available to us historically. Now, one of our biggest challenges is determining how to integrate data and maximize data potential. Our study demonstrates one way in which to test a hypothesis by combining multi-omic data and community metabolic models. Specifically, we assess hydrogen sulfide production in colorectal cancer based on stool, mucosa, and tissue samples collected on and off the tumor site within the same individuals. 16S rRNA microbial community and abundance data were used to select and inform the metabolic models. We then used MICOM, an open source platform, to track the metabolic flux of hydrogen sulfide through a defined microbial community that either represented on-tumor or off-tumor sample communities. We also performed targeted and untargeted metabolomics, and used the former to quantitatively evaluate our model predictions. A deeper look at the models identified several unexpected but feasible reactions, microbes, and microbial interactions involved in hydrogen sulfide production for which our 16S and metabolomic data could not account. These results will guide future in vitro, in vivo, and in silico tests to establish why hydrogen sulfide production is increased in tumor tissue.
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