Diet diversity and environment determine the intestinal microbiome and bacterial pathogen load of fire salamanders
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ABSTRACT:
SUBMITTER: Wang Y
PROVIDER: S-EPMC8516891 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundDiet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos) and relates these to food resources consumed by bears.Methodology/principal findingsFeces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids.ConclusionThis is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.
| S-EPMC3240615 | biostudies-literature
Project description:The intestinal immune system mounts inflammatory responses to pathogens but tolerates harmless commensal microbiota. Various mechanisms for pathogen/non-pathogen discrimination have been proposed but their general relevance for inflammation control is unclear. Here, we compared intestinal responses to pathogenic Salmonella and non-pathogenic E. coli. Both microbes entered intestinal Peyer's patches and, surprisingly, induced qualitatively and quantitatively similar initial inflammatory responses revealing a striking discrimination failure. Diverging inflammatory responses only occurred when Salmonella subsequently proliferated and induced escalating neutrophil infiltration, while harmless E. coli was rapidly cleared from the tissue and inflammation resolved. Transient intestinal inflammation induced by harmless E. coli tolerized against subsequent exposure thereby preventing chronic inflammation during repeated exposure. These data revealed a striking failure of the intestinal immune system to discriminate pathogens from harmless microbes based on distinct molecular signatures. Instead, appropriate intestinal responses to gut microbiota might be ensured by immediate inflammatory responses to any rise in microbial tissue loads, and desensitization after bacterial clearance.
| S-EPMC3346762 | biostudies-literature
Project description:The study of traditional populations provides a view of human-associated microbes unperturbed by industrialization, as well as a window into the microbiota that co-evolved with humans. Here we discuss our recent work characterizing the microbiota from the Hadza hunter-gatherers of Tanzania. We found seasonal shifts in bacterial taxa, diversity, and carbohydrate utilization by the microbiota. When compared to the microbiota composition from other populations around the world, the Hadza microbiota shares bacterial families with other traditional societies that are rare or absent from microbiotas of industrialized nations. We present additional observations from the Hadza microbiota and their lifestyle and environment, including microbes detected on hands, water, and animal sources, how the microbiota varies with sex and age, and the short-term effects of introducing agricultural products into the diet. In the context of our previously published findings and of these additional observations, we discuss a path forward for future work.
| S-EPMC6546328 | biostudies-literature
Project description:The fire blight pathogen, Erwinia amylovora (EA), causes significant economic losses in rosaceae fruit crops. Recent genome sequencing efforts have explored genetic variation, population structure, and virulence levels in EA strains. However, the genomic aspects of population bottlenecks and selection pressure from geographical isolation, host range, and management practices are yet unexplored. We conducted a comprehensive analysis of whole genome sequences of 41 strains to study genetic diversity, population structure, and the nature of selection affecting sub-population differentiation in EA. We detected 72,741 SNPs and 2,500 Indels, representing about six-fold more diversity than previous reports. Moreover, nonsynonymous substitutions were identified across the effector regions, suggesting a role in defining virulence of specific strains. EA plasmids had more diversity than the chromosome sequence. Population structure analysis identified three distinct sub-groups in EA strains, with North American strains displaying highest genetic diversity. A five kilobase genomic window scan showed differences in genomic diversity and selection pressure between these three sub-groups. This analysis also highlighted the role of purifying and balancing selection in shaping EA genome structure. Our analysis provides novel insights into the genomic diversity and selection forces accompanying EA population differentiation.
| S-EPMC6768868 | biostudies-literature
Project description:Plant polysaccharide intervention has shown significant potential to combat obesity. However, studies on animal polysaccharides are indeed rare. The aim of this study was to investigate the potential functions of CIP (IL) on obesity, intestinal microflora dysbiosis, and the possible protection of intestinal barrier in mice fed with high-fat diet (HFD). Our results revealed that after 13 weeks, the HFD+L (high-fat diet + 25 mg/kg CIP) group showed significantly more weight loss and fat accumulation relative to the HFD+H (high-fat diet + 50 mg/kg CIP) group. Furthermore, CIP intervention modulated lipid metabolism and mRNA levels of inflammatory mediators in liver. Overall, CIP clearly improved the intestinal barrier in HFD-fed mice. Additionally, we observed that CIP intervention improved intestinal microbiota community richness and diversity in HFD-fed mice. The CIP intervention mice group showed a relatively low Firmicutes to Bacteroidetes ratio compared to the HFD group. This study concluded that CIP could be used as a functional food to prevent adipocyte accumulation, reduce systemic inflammation, and protect the intestinal barrier.
| S-EPMC9573006 | biostudies-literature
Project description:The intestinal microbiome was examined from fecal pellets of animals with genetic targeting of the BTLA inhibitory receptor and the TNFR superfamily member HVEM, or in animals treated with agonist antibodies specific for BTLA.
2022-02-08 | GSE195890 | GEO
Project description:The analysis of transcriptomes is well-established and increasingly affordable in studies at the interface of ecology and evolution. Expression analysis of thousands of genes in parallel reveals functions and pathways involved in relevant phenotypic differentiation. The application of such methods typically involves the sacrifice of the analysed organisms, which is potentially subject to ethical and legal constraints. As an alternative to lethal sampling, transcriptome analyses can be performed using small biopsies of dispensable tissues. It has to be verified, however, to what extent such results are representative of the whole organism. Here, we use a custom microarray to compare transcriptomes of tail-clip samples with those of the remaining whole-body of fire salamander larvae (Salamandra salamandra). The microarray was calibrated using target RNA to validate the performance of each probe. We varied water temperature to test whether the thermal response in gene expression can be characterized in both types of sample. A large fraction (51 %) of the differentially expressed genes showed parallel changes for both tail clips and whole bodies in response to temperature. While sets of differentially expressed were not identical, they largely belonged to the same functional categories. The gene functions thus revealed a common thermal response of larvae irrespective of the sampled tissue. This included an overexpression of mitochondrial transcripts, an expected thermal acclimatization response of ectotherms. Hence, ecological transcriptomics based on small biopsies represent an alternative to the analysis of lethally sampled tissues in situations where the sacrifice of individuals is not an option. Larvae of European Fire salamander were exposed to two different temperatures (9°C & 17°C; n(cold) = 6, n(warm) = 6, n(total) = 12). The transcriptome response to temperature was assessed based on RNA extracted from tail tips, which can be sampled without sacrificing the individual, and based on RNA extracted from the remaining whole body. Results from the analysis of both tissues were compared.
2015-06-20 | E-GEOD-70054 | biostudies-arrayexpress
Project description:Discordance between mitochondrial and nuclear patterns of population genetic structure is providing key insights into the eco-evolutionary dynamics between and within species, and their assessment is highly relevant to biodiversity monitoring practices based on DNA barcoding approaches. Here, we investigate the population genetic structure of the fire salamander Salamandra salamandra in peninsular Italy. Both mitochondrial and nuclear markers clearly identified two main population groups. However, nuclear and mitochondrial zones of geographic transition between groups were located 600 km from one another. Recent population declines in central Italy partially erased the genetic imprints of past hybridization dynamics. However, the overall pattern of genetic variation, together with morphological and fossil data, suggest that a rampant mitochondrial introgression triggered the observed mitonuclear discordance, following a post-glacial secondary contact between lineages. Our results clearly show the major role played by reticulate evolution in shaping the structure of Salamandra salamandra populations and, together with similar findings in other regions of the species' range, contribute to identify the fire salamander as a particularly intriguing case to investigate the complexity of mechanisms triggering patterns of mitonuclear discordance in animals.
| S-EPMC6123427 | biostudies-literature
Project description:BackgroundSalmonella is one of the most significant food-borne pathogens to affect humans and agriculture. While it is well documented that Salmonella infection triggers host inflammation, the impacts on the gut environment are largely unknown. A CBA/J mouse model was used to evaluate intestinal responses to Salmonella-induced inflammation. In parallel, we evaluated chemically induced inflammation by dextran sodium sulfate (DSS) and a non-inflammation control. We profiled gut microbial diversity by sequencing 16S ribosomal ribonucleic acid (rRNA) genes from fecal and cecal samples. These data were correlated to the inflammation marker lipocalin-2 and short-chain fatty acid concentrations.ResultsWe demonstrated that inflammation, chemically or biologically induced, restructures the chemical and microbial environment of the gut over a 16-day period. We observed that the ten mice within the Salmonella treatment group had a variable Salmonella relative abundance, with three high responding mice dominated by >46% Salmonella at later time points and the remaining seven mice denoted as low responders. These low- and high-responding Salmonella groups, along with the chemical DSS treatment, established an inflammation gradient with chemical and low levels of Salmonella having at least 3 log-fold lower lipocalin-2 concentration than the high-responding Salmonella mice. Total short-chain fatty acid and individual butyrate concentrations each negatively correlated with inflammation levels. Microbial communities were also structured along this inflammation gradient. Low levels of inflammation, regardless of chemical or biological induction, enriched for Akkermansia spp. in the Verrucomicrobiaceae and members of the Bacteroidetes family S24-7. Relative to the control or low inflammation groups, high levels of Salmonella drastically decreased the overall microbial diversity, specifically driven by the reduction of Alistipes and Lachnospiraceae in the Bacteroidetes and Firmicutes phyla, respectively. Conversely, members of the Enterobacteriaceae and Lactobacillus were positively correlated to high levels of Salmonella-induced inflammation.ConclusionsOur results show that enteropathogenic infection and intestinal inflammation are interrelated factors modulating gut homeostasis. These findings may prove informative with regard to prophylactic or therapeutic strategies to prevent disruption of microbial communities, or promote their restoration.
| S-EPMC5408407 | biostudies-literature
Project description:While the importance of changes in host biodiversity for disease risk continues to gain empirical support, the influence of natural variation in parasite diversity on epidemiological outcomes remains largely overlooked. Here, we combined field infection data from 2,191 amphibian hosts representing 158 parasite assemblages with mechanistic experiments to evaluate the influence of parasite richness on both parasite transmission and host fitness. Using a guild of larval trematode parasites (six species) and an amphibian host, our experiments contrasted the effects of parasite richness vs. composition, observed vs. randomized assemblages, and additive vs. replacement designs. Consistent with the dilution effect hypothesis extended to intrahost diversity, increases in parasite richness reduced overall infection success, including infections by the most virulent parasite. However, the effects of parasite richness on host growth and survival were context dependent; pathology increased when parasites were administered additively, even when the presence of the most pathogenic species was held constant, but decreased when added species replaced or reduced virulent species, emphasizing the importance of community composition and assembly. These results were similar or stronger when community structures were weighted by their observed frequencies in nature. The field data also revealed the highly nested structure of parasite assemblages, with virulent species generally occupying basal positions, suggesting that increases in parasite richness and antagonism in nature will decrease virulent infections. Our findings emphasize the importance of parasite biodiversity and coinfection in affecting epidemiological responses and highlight the value of integrating research on biodiversity and community ecology for understanding infectious diseases.
| S-EPMC3384156 | biostudies-literature