Chao1 Estimator Research Articles

The Microbial Perspective: A Systematic Literature Review on Hypertension and Gut Microbiota

Background: Understanding the causes of hypertension is important in order to prevent the disease. Gut microbiota (GM) seems to play an important role, but the detailed physiology remains elusive, with alpha diversity being the most studied indicator. Objectives: This review aimed to systematically synthesize data on gut microbiota (alpha diversity) and hypertension. Methods: Databases, including MEDLINE/PubMed, Scopus, and EMBASE, and citations were systematically queried. We retrieved articles reporting the association between gut microbiota and hypertension. A valid critical appraisal tool was also used to investigate the quality of the included studies. Results: Eighteen eligible studies met our inclusion criteria. In this report, we focused on the following indices of alpha diversity: Shannon, Chao1, Simpson, and Abundance-based Coverage Estimator (ACE) indices. Several studies observed a significantly lower Shannon index in hypertensive patients compared to the healthy control group. Nevertheless, no statistically significant difference was found for the Chao1, Simpson, and ACE indices between hypertensive patients and controls. A higher Firmicutes-to-Bacteroidetes ratio (F/B ratio) was consistently observed in hypertensive patients compared to healthy controls, indicating potential dysbiosis in the gut microbiota. Conclusions: Our systematic review indicates that hypertensive patients may exhibit an imbalance in gut microbiota, evidenced by decreased alpha diversity and an elevated F/B ratio. However, the absence of statistically significant differences in secondary diversity indices (Chao1, Simpson, and ACE) highlights the need for further research. Well-designed, large-scale studies are necessary to clarify these associations and explore the role of gut microbiota in hypertension development.

Composition and diversity of soil microbial communities change by introducing Phallus impudicus into a Gastrodia elata Bl.-based soil

BackgroundThe Gastrodia elata Bl. is an orchid, and its growth demands the presence of Armillaria species. The strong competitiveness of Armillaria species has always been a concern of major threat to other soil organisms, thus disrupting the equilibrium of soil biodiversity. Introducing other species to where G. elata was cultivated, could possibly alleviate the problems associated with the disequilibrium of soil microenvironment; however, their impacts on the soil microbial communities and the underlying mechanisms remain unclear. To reveal the changes of microbial groups associated with soil chemical properties responding to different cultivation species, the chemical property measurements coupled with the next-generation pyrosequencing analyses were applied with soil samples collected from fallow land, cultivation of G. elata and Phallus impudicus, respectively.ResultsThe cultivation of G. elata induced significant increases (p < 0.05) in soil pH and NO3-N content compared with fallow land, whereas subsequent cultivation of P. impudicus reversed these G. elata-induced increases and was also found to significantly increase (p < 0.05) the content of soil NH4+-N and AP. The alpha diversities of soil microbial communities were significantly increased (p < 0.01) by cultivation of G. elata and P. impudicus as indicated with Chao1 estimator and Shannon index. The structure and composition of soil microbial communities differed responding to different cultivation species. In particular, the relative abundances of Bacillus, norank_o_Gaiellales, Mortierella and unclassified_k_Fungi were significantly increased (p < 0.05), while the abundances of potentially beneficial genera such as Acidibacter, Acidothermus, Cryptococcus, and Penicillium etc., were significantly decreased (p < 0.05) by cultivation of G. elata. It’s interesting to find that cultivation of P. impudicus increased the abundances of these genera that G. elata decreased before, which contributed to the difference of composition and structure. The results of CCA and heatmap indicated that the changes of soil microbial communities had strong correlations with soil nutrients. Specifically, among 28 genera presented, 50% and 42.9% demonstrated significant correlations with soil pH and NO3-N in response to cultivation of G. elata and P. impudicus.ConclusionsOur findings suggested that the cultivation of P. impudicus might have potential benefits as result of affecting soil microorganisms coupled with changes in soil nutrient profile.

Gut microbial signatures of patients with diarrhea-predominant irritable bowel syndrome and their healthy relatives

Abstract Aims Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, encompassing diarrhea-predominant irritable bowel syndrome (IBS-D). Here, we utilized 16S rDNA gene sequencing to identify potential microbial drivers of IBS-D. Methods and Results A total of 30 healthy relatives and 27 patients with IBS-D were recruited. Clinical data and fecal samples were collected from patients and controls. 16S rDNA gene sequencing was performed to obtain fecal bacterial data. Differences in community composition were evaluated utilizing analysis of similarity (ANOSIM) using Bray–Curtis dissimilarity. The Wilcoxon rank sum test was used to compare differences in taxa and functional pathways. Finally, the key gut microbiota was identified using the random forest algorithm. Gut microbiota diversity, estimated through the Observe, Chao1, and abundance-based coverage estimator (ACE) indices, was significantly lower in the IBS-D patients than in the healthy relatives. ANOSIM analysis further confirmed significant differences in the composition of the gut microbiota between IBS-D patients and healthy relatives, with an R value of 0.106 and a P-value of 0.005. Notably, the IBS-D patients exhibited a significant enrichment of specific bacterial genera, including Fusicatenibacter, Streptococcus, and Klebsiella, which may possess potential pathogenic properties. In particular, the bacterial genus Klebsiella demonstrated a positive correlation with irritable bowel syndrome severity scoring system scores. Conversely, healthy subjects showed enrichment of bacterial genera such as Alistipes, Akkermansia, and Dialister, which may be beneficial bacteria in IBS-D. Utilizing the random forest model, we developed a discriminative model for IBS-D based on differential bacterial genera. This model exhibited impressive performance, with an area under the curve value of 0.90. Additionally, our analysis did not reveal any gender-specific differences in the microbiota community composition among IBS-D patients. Conclusions Our findings offer preliminary insights into the potential relationship between intestinal microbiota and IBS-D. The identification model for IBS-D, grounded in gut microbiota, holds promising prospects for improving early diagnosis of IBS-D.

Variation in Pesticide Toxicity in the Western Honey Bee (Apis mellifera) Associated with Consuming Phytochemically Different Monofloral Honeys

Insecticide toxicity to insect herbivores has long been known to vary across different host plants; this phenomenon has been widely documented in both foliage-feeders and sap-feeders. Species-specific phytochemical content of hostplant tissues is assumed to determine the pattern of induction of insect enzymes that detoxify insecticides, but specific phytochemicals have rarely been linked to host plant-associated variation in pesticide toxicity. Moreover, no studies to date have examined the effects of nectar source identity and phytochemical composition on the toxicity of insecticides to pollinators. In this study, we compared LD50 values for the insecticide bifenthrin, a frequent contaminant of nectar and pollen in agroecosystems, in the western honey bee, Apis mellifera, consuming three phytochemically different monofloral honeys: Nyssa ogeche (tupelo), Robinia pseudoacacia (black locust), and Fagopyrum esculentum (buckwheat). We found that bifenthrin toxicity (LD50) values for honey bees across different honey diets is linked to their species-specific phytochemical content. The profiles of phenolic acids and flavonoids of buckwheat and locust honeys are richer than is the profile of tupelo honey, with buckwheat honey containing the highest total content of phytochemicals and associated with the highest bifenthrin LD50 in honey bees. The vector fitting in the ordination analysis revealed positive correlations between LD50 values and two honey phytochemical richness estimates, Chao1 and Abundance-based Coverage Estimator (ACE). These findings suggest unequal effects among different phytochemicals, consistent with the interpretation that certain compounds, including ones that are rare, may have a more pronounced effect in mitigating pesticide toxicity.

Association between Soil Physicochemical Properties and Bacterial Community Structure in Diverse Forest Ecosystems.

Although the importance of the soil bacterial community for ecosystem functions has long been recognized, there is still a limited understanding of the associations between its community composition, structure, co-occurrence patterns, and soil physicochemical properties. The objectives of the present study were to explore the association between soil physicochemical properties and the composition, diversity, co-occurrence network topological features, and assembly mechanisms of the soil bacterial community. Four typical forest types from Liziping Nature Reserve, representing evergreen coniferous forest, deciduous coniferous forest, mixed conifer-broadleaf forest, and its secondary forest, were selected for this study. The soil bacterial community was analyzed using Illumina MiSeq sequencing of 16S rRNA genes. Nonmetric multidimensional scaling was used to illustrate the clustering of different samples based on Bray-Curtis distances. The associations between soil physicochemical properties and bacterial community structure were analyzed using the Mantel test. The interactions among bacterial taxa were visualized with a co-occurrence network, and the community assembly processes were quantified using the Beta Nearest Taxon Index (Beta-NTI). The dominant bacterial phyla across all forest soils were Proteobacteria (45.17%), Acidobacteria (21.73%), Actinobacteria (8.75%), and Chloroflexi (5.06%). Chao1 estimator of richness, observed ASVs, faith-phylogenetic diversity (faith-PD) index, and community composition were distinguishing features of the examined four forest types. The first two principal components of redundancy analysis explained 41.33% of the variation in the soil bacterial community, with total soil organic carbon, soil moisture, pH, total nitrogen, carbon/nitrogen (C/N), carbon/phosphorous (C/P), and nitrogen/phosphorous (N/P) being the main soil physicochemical properties shaping soil bacterial communities. The co-occurrence network structure in the mixed forest was more complex compared to that in pure forests. The Beta-NTI indicated that the bacterial community assembly of the four examined forest types was collaboratively influenced by deterministic and stochastic ecological processes.

Diversity and species richness of land snails inhabiting an impacted macro-zone-Mfamosing limestone hill in Sub-Saharan Region

The land snail diversity and abundance and some ecological aspects of the fauna in a threatened limestone hill in Mfamosing, Cross Rivers state, Nigeria was investigated between May 2017 and June 2018. Twelve plots of 10 m x 10 m each using a combination of leaf litter in the forest floor (litter and topsoil in a total of ninety sample bags) were sampled from which shells were extracted by handpicking. A total of 289 (two hundred and eighty-nine) specimens representing twenty-three species in seven molluscan families were recorded. The carnivorous Streptaxidae family dominated the fauna regarding species richness while the family Urocyclidae dominated species abundance. The families Eucolinidae and Aillyidae accounted for the least dominant species. The family Streptaxidae with seven species accounted for over 30% of the mollusk abundance, while Urocyclidae had the highest number of individual specimens. True estimates of diversity using Chao2 and second-order Jack-Knife estimators yielded 25 and 24 species respectively. The Land Snail diversity in Mfamosing limestone hill when compared with those from other parts of Nigeria (Okomu in Edo State) and some other parts of the world (Sabah, Malaysia) is relatively high, with moderate levels of species abundance, showing relatively high differentiation, local dominance and endemism by few species. This reveals that Mfamosing limestone hill is one of the biodiversity hotspots for terrestrial mollusks and requires urgent conservation measures, given the current rate of Limestone quarrying in the region.

Ischaemic stroke patients present sex differences in gut microbiota.

Gut microbiota plays a role in the pathophysiology of ischaemic stroke (IS) through the bidirectional gut-brain axis. Nevertheless, little is known about sex-specific microbiota signatures in IS occurrence. A total of 89 IS patients and 12 healthy controls were enrolled. We studied the taxonomic differences of the gut microbiota between men and women with IS by shotgun metagenomic sequencing. To evaluate the causal effect of several bacteria on IS risk, we performed a two-sample Mendelian randomisation (MR) with inverse-variance weighting (IVW) using genome-wide association analysis (GWAS) summary statistics from two cohorts of 5959 subjects with genetic and microbiota data and 1,296,908 subjects with genetic and IS data, respectively. α-Diversity analysis measured using Observed Species (p = 0.017), Chao1 (p = 0.009) and Abundance-based Coverage Estimator (p = 0.012) indexes revealed that IS men have a higher species richness compared with IS women. Moreover, we found sex-differences in IS patients in relation to the phylum Fusobacteria, class Fusobacteriia, order Fusobacteriales and family Fusobacteriaceae (all Bonferroni-corrected p < 0.001). MR confirmed that increased Fusobacteriaceae levels in the gut are causally associated with an increased risk of IS (IVW p = 0.02, β = 0.32). Our study is the first to indicate that there are gut microbiome differences between men and women with IS, identifying high levels of Fusobacteriaceae in women as a specific risk factor for IS. Incorporating sex stratification analysis is important in the design, analysis and interpretation of studies on stroke and the gut microbiota.

Soil centipedes (Chilopoda, Geophilomorpha) in the Val Camonica forests (Southern Alps): species composition and richness.

Soil centipedes (Chilopoda, Geophilomorpha) are a widespread group of predators in the forest soils of the European Alps. While in the eastern and western parts of the Southern Prealps, larger efforts were devoted to sample and study the geophilomorph fauna, little is known about species richness and composition of geophilomorph communities in the central part of Southern Prealps. In this work, five sites located in the Val Camonica were surveyed by hand searching, between November 2021 and July 2022 and their species richness was estimated applying non-parametrical statistical methods (Chao-1 and Abundance-based Coverage Estimator) to account for incomplete detection. A total of 18 species were found amongst the five sites. A maximum of 12 species were recorded in each single site, while estimates suggest that another 1-3 species were likely undetected. Species composition were found highly variable also between sites with similar species richness.

Comparing avian species richness estimates from structured and semi-structured citizen science data

Citizen science, including structured and semi-structured forms, has become a powerful tool to collect biodiversity data. However, semi-structured citizen science data have been criticized for higher variability in quality, including less information to adjust for imperfect detection and uneven duration that bias the estimates of species richness. Species richness estimators may quantify bias in estimates. Here, we test the effectiveness of Chao1 estimator in eBird (semi-structured) by comparing it to averaged species richness in Breeding Bird Survey Taiwan, BBS (structured) and quantifying bias. We then fit a power function to compare bias while controlling for differences in count duration. The Chao1 estimator increased the species richness estimates of eBird data from 56 to 69% of the average observed BBS and from 47 to 59% of the average estimated BBS. Effects of incomplete short duration samples and variability in detectability skills of observers can lead to biased estimates. Using the Chao1 estimator improved estimates of species richness from semi-structured and structured data, but the strong effect of singleton species on bias, especially in short duration counts, should be evaluated in advance to reduce the uncertainty of estimation processes.

Changes in the bacterial communities in chromium-contaminated soils.

Hexavalent chromium or Cr(VI) is essential to various industries, such as leather manufacturing and stainless steel production. Given that inevitable leakage from industries pollutes the soil and thereby affects the soil environment. Microbial communities could improve the quality of the soil. Abundant bacterial communities would significantly enhance the soil richness and resist external pressure, benefiting agriculture. But the pollution of heavy metal broke the balance and decrease the abundance of bacterial communities, which weak the self-adjust ability of soil. This study aimed to explore changes in the diversity of soil bacterial communities and to identify the influences of soil bacterial communities on enzymes in soil polluted by Cr(VI). The target soils were sampled quickly and aseptically. Their chromium content was detected through inductively coupled plasma-mass spectrometry, and bacterial microbiome communities were explored through MiSeq high-throughput sequencing. Then, the content of nitrite reductase and catalases were investigated through enzyme-linked immunosorbent assay (ELISA). Chromium content in polluted soils was higher than that in the control soils at all depths. Sobs, Chao1, Ace, and Shannon diversity estimators in the control were higher, whereas Simpson's diversity estimators in the control soils were lower than those of contaminated samples at all depths. Contaminants affected the composition of the bacterial community. The soil microbial species were relatively single and inhomogeneous in the polluted soils. The bacterial phyla in polluted and controlled soils include Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria, which differ markedly in abundance. The results of these observations provide insights into the ecotoxicological effects of Cr(VI) exposure to soil microorganisms. To sum up these results are critical for evaluating the stabilized state of microbial community structures, contributing to the assessment of the potential risk of metal accumulation in soils.

Building a baseline: a survey of the composition and distribution of the ichthyofauna of Guanabara Bay, a deeply impacted estuary

Abstract Biodiversity baselines are essential subsidies to evaluate how environmental changes and human impacts affect the special and temporal patterns of communities. This information is paramount to promote proper conservation and management for historically impacted environments such as Guanabara Bay, in southeastern Brazil. Here, we propose an ichthyofaunal baseline for this bay using gathered past data from 1889 to 2020, including literature records, scientific collections, biological sampling, and fisheries landing monitoring. A total of 220 species (203 teleosts and 17 elasmobranchs), distributed in 149 genera (136 teleosts and 13 elasmobranchs) and 72 families (61 teleosts and 11 elasmobranchs) were recorded, including the first record of a tiger-shark, Galeocerdo cuvier, in Guanabara Bay. Although the employed sampling effort was sufficient to represent the ichthyofauna in the middle and upper estuary, the Chao2 estimator indicates an even greater richness regarding the bay as a whole. Evidence of reduced abundance and probable local extinction over the decades was found, supporting the importance of implementing management and conservation strategies in the area. The ichthyofaunal distribution analyses revealed that areas close to conservation units are richer compared to their surroundings, indicating that this is an effective strategy to mitigate human impacts in the bay.

Estimating total species richness: Fitting rarefaction by asymptotic approximation

AbstractEstimating the number of species in a community is important for assessments of biodiversity. Previous species richness estimators are mainly based on nonparametric approaches. Although parametric asymptotic models have been applied, they received limited attention due to specific limitations. Here, we introduce parametric models fitting the probability‐based rarefied species richness curve that allow us to estimate the “Total Expected Species” (TES) in a community based on species' abundance data. We develop two approaches to calculate TES (termed “TESa” and “TESb”), based on two slightly different mathematical assumptions regarding Expected Species (ES) models. We provide R functions to calculate both these estimation approaches and their standard deviation. The function also enables users to visualize the estimation. We test the performance of TESa, TESb, and their average (TESab) across simulated and empirical data, and compare their bias, precision, and accuracy with other commonly used, nonparametric species richness estimators: the bias‐corrected (bc‐)Chao1 and the abundance‐based coverage estimator (ACE). Simulation reveals that in small samples TESa shows a tendency to overestimate and TESb to underestimate overall species richness. TESab performs well in bias, precision, and accuracy when compared with (bc‐)Chao1 and ACE estimators. Results from empirical data show that the variance generated from TES estimates is comparable with that for (bc‐)Chao1 and ACE. Our study demonstrates that rarefaction theory in combination with parametric approximation models provides a valuable new approach to estimate the species richness of incompletely sampled communities. Robust estimates are likely to be obtained where the observed number of species is greater than half of the TES estimation. When the ratio of TESa to the observed richness is ≫2, we suggest the use of TESb or TESab. Although more comprehensive comparisons with other estimators are suggested, we encourage researchers to consider the TES approach in their biodiversity studies as a complement to current existing estimators.

Distributional Trends and Species Richness of Maryland, USA, Stoneflies (Insecta: Plecoptera), with an Emphasis on the Appalachian Region

Faunistic studies of regional biodiversity of aquatic insects are increasing in importance as declines are noted globally. Federal and state government conservation attempts for rare and threatened species are predicated upon the initial research of specialized taxonomists and trained field biologists. The reporting of aquatic insect occurrence data provides a baseline for conservation agencies to compare water quality monitoring studies. Updated field work, literature reviews, and database queries for stoneflies from the mid-Atlantic United States of America state of Maryland necessitated an assessment of species diversity for the state. Seven new state records and one new literature record are presented, bringing the total number of species to 122. Chao1 estimates of species richness are presented for diversity hotspots and the state as a whole, indicating that increased sampling is still necessary to fully understand diversity patterns. Accompanying are assessments of elevation trends and adult presence patterns within nine families. Collections are predominantly restricted to the Appalachian region. Herein, we direct future efforts to focus on understudied regions. An outline of distribution knowledge for species is presented to inform upcoming State Wildlife Action Plans.

Checklist of the Elateridae (Coleoptera) of Montana, USA, with Taxonomic Notes

One hundred and eighty-four species of Elateridae in 54 genera are recorded from the state of Montana, representing an increase of 92 species from the 93 species recorded from previously published literature. Distribution within Montana is reported by county and includes 1,724 individual county records. EstimateS® was used to determine inventory completeness and predict the probable number of species expected in the state, which uses a Chao1 estimator. The Chao1 estimator mean predicts another 13 species remain to be discovered in the state. Selected genera are also provided with taxonomic notes that often highlight areas of potential future research and to highlight taxonomic issues or difficulties. The list also includes recently described genera to help establish limits for these new groups. The species concepts of Aeolus livens (LeConte, 1853) and Aeolus mellillus (Say, 1834) are clarified. A new combination, Megapenthes subtilis (LeConte, 1884), new combination, is proposed here. Specimens previously identified as Ampedus subtilis (LeConte) sensu Brooks 1960 are here identified as Ampedus nigricans Germar, 1834.

Island biogeography and human practices drive ecological connectivity in mosquito species richness in the Lakshadweep Archipelago

Mosquitoes are globally distributed and adapted to a broad range of environmental conditions. As obligatory hosts of many infectious pathogens, mosquito abundance and distribution are primarily determined by the presence and quality of larval habitats. To understand the dynamics and productivity of larval habitats in changing island environments, we conducted a four-month mosquito survey across ten inhabited islands in the Lakshadweep archipelago. Using fine-resolution larval habitat mapping, we recorded 7890 mosquitoes representing 13 species and 7 genera. Of these, four species comprised 95% of the total collections—Aedes albopictus (Stegomyia) was the dominant species followed by Armigeres subalbatus, Culex quinquefasciatus and Malaya genurostris. We found larval species richness was positively associated with the island area and mosquito larval richness (Chao1 estimator) was higher in artificial habitats than in natural habitats. Furthermore, mosquito species composition did not deteriorate with distance between islands. Mosquito abundance by species was associated with microclimatic variables—pH and temperature. We detected co-existence of multiple species at a micro-habitat level with no evidence of interactions like competition or predation. Our study analyzed and identified the most productive larval habitats –discarded plastic container and plastic drums contributing to high larval indices predicting dengue epidemic across the Lakshadweep islands. Our data highlight the need to devise vector control strategies by removal of human-induced plastic pollution (household waste) which is a critical driver of disease risk.

Effect of 6-Methoxybenzoxazolinone on the Cecal Microbiota of Adult Male Brandt's Vole.

The anti-microbial effects of plant secondary metabolite (PSM) 6-methoxybenzoxazolinone (6-MBOA) have been overlooked. This study investigated the effect of 6-MBOA on the cecal microbiota of adult male Brandt’s voles (Lasiopodomys brandtii), to evaluate its effect on the physiology of mammalian herbivores. The growth of voles was inhibited by 6-MBOA. A low dose of 6-MBOA enhanced the observed species, as well as the Chao1 and abundance-based coverage estimator (ACE) indices and introduced changes in the structure of cecal microbiota. The abundance of the phylum Tenericutes, classes Mollicutes and Negativicutes, order Selenomonadales, families Ruminococcaceae and Veillonellaceae, genera Quinella, Caproiciproducens, Anaerofilum, Harryflintia, and unidentified Spirochaetaceae in the cecal microbiota was enhanced upon administration of a low dose of 6-MBOA, which also inhibited glucose metabolism and protein digestion and absorption in the cecal microbiota. 6-MBOA treatment also stimulated butyrate production and dose-dependently enhanced the metabolism of xenobiotics in the cecal microbiome. Our findings indicate that 6-MBOA can affect Brandt’s voles by inducing changes in the abundance of cecal bacteria, thereby, altering the contents of short-chain fatty acids (SCFAs) and pathway intermediates, ultimately inhibiting the growth of voles. Our research suggests that 6-MBOA could potentially act as a digestion-inhibiting PSM in the interaction between mammalian herbivores and plants.

Gut associated culturable bacterial community in intertidal polychaete worms (Annelida: Polychaeta), their characterization and implications in captive shrimp aquaculture

Polychaetes supplements play a crucial role in the dietary requirements of shrimps reared under captive culture. Due to their high demand, wild captured worms are used extensively as supplementary feed for the broodstocks. However, the gut microbiota composition of the polychaetes is rarely investigated. In the present study, the culturable fraction of gut microbiota of two native polychaete species, Marphysa madrasi and Namalycastis sp., that are currently used as live supplemental feed by shrimp brooders, were analysed. The culture-dependent technique yielded a total of 39 bacterial isolates, which grouped into 23 unique phylotypic clusters based on amplified ribosomal DNA restriction analysis (ARDRA) profiling. The 16S rRNA gene sequencing of these 23 gut isolates revealed bacterial communities with probiotic potential and a few shrimp and human pathogens. The gut-associated bacterial community is dominated by three bacterial phyla, the Firmicutes, Actinobacteria, and Proteobacteria, composed of 10 different genera. Moreover, there were differences in the bacterial communities between the two polychaetes investigated in this study. The Shannon, Simpson, Chao1 and Abundance-based Coverage Estimator (ACE) index revealed that M. madrasi have significantly higher species diversity and richness than Namalycastis sp. in the gut. Screening for hydrolytic enzyme production revealed several bacterial species with probiotic applications, such as Bacillus subtilis, B. licheniformis, B. pumilus, B. megaterium, and B. halotolerans. On the other hand, a few opportunistic human pathogens, such as B. cereus, Gordonia terrae, Microbacterium paraoxydans, Staphylococcus epidermidis, and Staphylococcus gallinarum, were also identified. Overall, the results of this study revealed that the bacterial assemblages associated with the gut of intertidal polychaete worms can serve as excellent probiotic candidates.

Calcium Propionate Supplementation Has Minor Effects on Major Ruminal Bacterial Community Composition of Early Lactation Dairy Cows.

Calcium propionate is one kind of good source for preventing and treating hypocalcemia and ketosis for dairy cows in early lactation. However, little is known about the effects of different feeding levels of calcium propionate on the ruminal bacterial community of early lactation dairy cows. This study aimed to explore the effects of different calcium propionate feeding levels on the ruminal fermentation and bacterial community composition of early lactation dairy cows. Twenty-four multiparous cows were randomly allocated into control (CON), low calcium propionate (LCaP), medium calcium propionate (MCaP), and high calcium propionate (HCaP) groups with six cows per group after calving. The CON group cows were fed the normal total mixed ration (TMR), and the cows of the LCaP, MCaP, and HCaP groups were fed TMR supplemented with 200, 350, and 500 g/day calcium propionate for 35 days after calving, respectively. The rumen fermentation parameters were measured every week, and the ruminal bacterial community composition of the last week was analyzed by 16S rRNA gene sequencing. Under the same diet, the rumen pH showed no difference among the four groups, but the content of microbial crude protein (MCP) and ammonia nitrogen quadratically decreased and linearly increased with calcium propionate supplementation, respectively. The feeding of calcium propionate linearly increased the concentrations of total volatile fatty acid (VFA), acetate, propionate, butyrate, iso-valerate, and valerate in the rumen. In all the treatment groups, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla, and Prevotella_1 and Succiniclasticum were the dominant genera in the rumen. Compared with the CON group, the addition of calcium propionate to the early lactation dairy cows quadratically improved the alpha diversity index of Chao1 estimator and observed species, but had little effect on the relative abundance of the major bacterial at phyla and genera level. These results suggested different levels of calcium propionate supplementation improved the rumen fermentation and the ruminal bacterial diversity but had little impact on the major ruminal bacterial community composition of dairy cows in early lactation.

Altered gut microbiota richness in individuals with a history of lateral ankle sprain

ABSTRACT This study aimed to examine differences in the intestinal microbiota diversity in individuals with and without a history of a lateral ankle sprain (LAS). Fifty male college student athletes with (n=32) and without (n=18) a LAS history participated in this study. Faecal samples were collected in the morning after awakening during an off-season, and faecal microbiota were characterized via bacteria 16S rRNA amplicon sequencing. Alpha-diversity metrics and ß-diversity indices were calculated to assess the gut microbiota diversity. The LAS-history group significantly had lower Chao1 (p=0.020) and abundance-based coverage estimators (p=0.035) indices compared to the control group. Gut microbiota composition was not significantly different between athletes with a LAS history and controls (R2 =0.01, p 0.414). Athletes with a history of LASs had significantly higher proportions of Bacteroides Fragilis (p=0.024) and Ruminococcus Gnavus (p=0.021) compared with controls. The gut microbiota of athletes with a LAS history had less richness compared to controls, indicating potential associations between a LAS and the gut microbiota. This study highlights the potential link of a LAS to global health. This study may help raise awareness of strategies to prevent long-term health-related negative consequences in people suffering from LASs.

Effects of replacing fish meal with corn gluten meal on growth performance, intestinal microbiota, mTOR pathway and immune response of abalone Haliotis discus hannai

Corn gluten meal (CGM) is used as a protein source in aquafeeds. However, the potential for replacing fish meal (FM) with CGM in abalone feeds has not been adequately evaluated. A 110-day feeding trial was conducted to evaluate effects of replacing FM with CGM on abalone Haliotis discus hannai (initial weight: 21.83 ± 0.25 g). The control diet (CGM0) was designed to contain 20% of FM. The other four isonitrogenous (about 30% of crude protein) and isolipidic (about 4% of crude lipid) experimental diets were formulated with CGM protein replacing 25%, 50%, 75% and 100% of dietary FM protein, respectively. The five experimental diets were named as CGM0, CGM25, CGM50, CGM75 and CGM100, respectively. Results showed that no significant differences were found in survival rate among all the groups. Weight gain rate (WGR) of abalone in the CGM100 group was significantly lower than that in the control group. There were no significant differences in WGR among the CGM25, CGM50, CGM75 and the control groups. The increasing dietary CGM inclusion level elevated the operational taxonomic units, ACE estimator and Chao1 estimator, and changed the intestinal microbiota composition in abalone. The activities of trypsin, alanine transaminase, aspartate transaminase and Na+, K+-ATPase in digestive gland were significantly decreased when replacement level over 50%. The increasing dietary CGM inclusion level significantly downregulated the expressions of ribosomal S6 protein kinase (s6k), mammalian target of rapamycin (mtor) and eukaryotic translation initiation factor 4E (eif4e) in digestive gland. The CGM75 and CGM100 groups had significant lower activities of catalase and lysozyme in cell-free hemolymph and digestive gland. In conclusion, CGM could replace 75% of dietary FM (equivalent to 16.2% of CGM inclusion level in the diet) without significantly affecting the growth of abalone. However, high inclusion levels of CGM in diets (> 10.8%) had negative effects on intestinal microbiota, mTOR pathway and immunity in abalone.