Alpha Diversity Research Articles

Location Matters: Variations in Cloacal Microbiota Composition of Spatially Separated Freshwater Turtles.

The gut microbiota of vertebrates is malleable and may be shaped by both intrinsic and extrinsic factors. Here, the effect that geography has on the cloacal microbiota of two species of Australian freshwater chelonians, eastern longneck turtle (Chelodina longicollis) and Macquarie River turtle (Emydura macquarii), captured from waterbodies with different levels of anthropogenic pressure was investigated. We analysed the microbiota composition, structure and diversity through 16S rRNA gene amplicon sequencing. It was hypothesised that animals from less disturbed environments would harbour a more diverse cloacal microbial population. The cloacal microbiotas from 93 turtles (C. longicollis n = 78; E. macquarii n = 15), from five locations, were analysed. For both species, the most predominant phylum was Proteobacteria. Cloacal microbiota alpha diversity varied significantly between the C. longicollis from all locations, but no differences were found for E. macquarii. In C. longicollis, turtles from wetlands within the centre of Melbourne had the lowest alpha diversity metrics, while the highest alpha diversity values were seen in turtles captured from an undisturbed rural waterbody. Beta diversity, obtained by weighted UniFrac distance, showed significant differences between locations of capture for both species of turtles in this investigation. For C. longicollis, 87 biomarkers were identified responsible for explaining differences between locations, and in E. macquarii, 42 biomarkers were found. This is the first study to explore the cloacal microbiota composition of the eastern longneck turtle and gives greater insight into microbial community structures in Macquarie River turtles. Our study demonstrated that cloacal microbiota composition of freshwater turtles was significantly influenced by locality and that disrupted environments may reduce microbial diversity in C. longicollis. Interestingly, we discovered that the effects of location contrasted significantly between species for alpha diversity with differences discovered for C. longicollis but not E. macquarii. However, for both species, beta diversity was notably influenced by habitat type. These results highlight the need to interpret chelonian microbiota data in the context of geography and human disturbance of the environment.

Baseline gut microbiome alpha diversity predicts chemotherapy-induced gastrointestinal symptoms in patients with breast cancer.

Chemotherapy frequently causes debilitating gastrointestinal symptoms, which are inadequately managed by current treatments. Recent research indicates the gut microbiome plays a role in the pathogenesis of these symptoms. The current study aimed to identify pre-chemotherapy microbiome markers that predict gastrointestinal symptom severity after breast cancer chemotherapy. Fecal samples, blood, and gastrointestinal symptom scores were collected from 59 breast cancer patients before, during, and after chemotherapy. Lower pre-chemotherapy microbiome alpha diversity and abundance of specific microbes (e.g., Faecalibacterium) predicted greater chemotherapy-induced gastrointestinal symptoms. Notably, tumor and diet characteristics were associated with lower pre-chemotherapy alpha diversity. Lower baseline alpha diversity also predicted higher chemotherapy-induced microbiome disruption, which was positively associated with diarrhea symptoms. The results indicate certain cancer patients have lower microbiome diversity before chemotherapy, which is predictive of greater chemotherapy-induced gastrointestinal symptoms and a less resilient microbiome. These patients may be strong candidates for pre-chemotherapy microbiome-directed preventative interventions (e.g., diet change).

Correlation between intestinal microbiota and urolithin metabolism in a human walnut dietary intervention.

This study is to investigate the relationship between the intestinal microbiota and urine levels of the ellagic acid-derived polyphenols, the urolithins, in a cohort of subjects following a three-week walnut dietary intervention. We longitudinally collected fecal and urine samples from 39 subjects before and after walnut consumption (2oz per day for 21days). 16S RNA gene sequencing was performed on fecal DNA to study the association between microbiota composition and the levels of nine urolithin metabolites, which were measured using UHPLC/Q-TOF-MS/MS. Fecal microbial composition was found to be significantly different between pre- and post-walnut intervention (beta diversity, FDR-p = 0.018; alpha diversity, p = 0.018). Roseburia, Rothia, Parasutterella, Lachnospiraceae UCG-004, Butyricicoccus, Bilophila, Eubacterium eligens, Lachnospiraceae UCG-001, Gordonibacter, Paraprevotella, Lachnospira, Ruminococcus torques, and Sutterella were identified as the 13 most significantly enriched genera after daily intake of walnuts. We observed 26 genera that were significantly associated with 7 urolithin metabolites, with 22 genera positively correlating after walnut supplementation (FDR-p ≤ 0.05). PICRUSt analysis showed that several inferred KEGG orthologs were associated with 4 urolithin metabolites after walnut intake. In this study, we found that walnut supplementation altered urolithin metabolites, which associates with specific changes in bacterial taxa and inferred functional contents.

Gut microbiota diversity is prognostic and associated withbenefit from chemo-immunotherapy in metastatic triple-negative breast cancer.

The gut microbiota influences multiple aspects of human health and disease. Several studies have indicated an association between the gut microbiota and response to immune checkpoint inhibitors in various cancers, but there is scarce data from breast cancer. The randomized ALICE trial demonstrated improved progression-free survival (PFS) from adding the programmed cell death 1 ligand 1 (PD-L1) inhibitor atezolizumab (atezo) to immunomodulating chemotherapy (chemo) in metastatic triple-negative breast cancer (mTNBC), even for PD-L1negative disease. Herein, we investigated the microbiota composition and dynamics in the ALICE patients and their association with clinical outcome, by analyzing fecal samples collected at baseline and after 8 weeks. We applied 16S (V3-V4) rRNA sequencing to characterize the diversity and taxonomic composition. Kaplan-Meier and Cox proportional hazard models were used for time-to-event analyses. We found that high alpha diversity by Faith's phylogenetic diversity (PD) at baseline was associated with prolonged PFS in the total study population and in the atezo-chemo arm, but not in the placebo-chemo arm. Moreover, Faith's PD appeared to be predictive of benefit from atezolizumab. Patients with high Faith's PD exhibited a PFS hazard ratio of 0.34 (P = 0.018) in favor of the atezo-chemo arm, compared to 0.83 (P = 0.62) in the low Faith's PD group. Faith's PD was significantly reduced during treatment. At baseline, Bifidobacterium was significantly overrepresented in patients without clinical benefit in the atezo-chemo arm, but not in the placebo-chemo arm. These findings suggest that alpha diversity by Faith's PD should be further investigated as a prognostic and predictive biomarker in patients with mTNBC receiving chemo-immunotherapy.

Sex-Induced Changes in Microbial Eukaryotes and Prokaryotes in Gastrointestinal Tract of Simmental Cattle

This study investigates gender-based differences in the gut microbiota of Simmental cattle, focusing on bacterial, archaeal, and fungal communities. Fecal samples were collected and analyzed using high-throughput sequencing, with taxonomic classification performed through the SILVA and UNITE databases. Alpha and beta diversity metrics were assessed, revealing significant differences in the diversity and composition of archaeal communities between males and females. Notably, females exhibited higher alpha diversity in archaea, while beta diversity analyses indicated distinct clustering of bacterial and archaeal communities by gender. The study also identified correlations between specific microbial taxa and hematological parameters, with Treponema and Methanosphaera showing gender-specific associations that may influence cattle health and productivity. These findings highlight the importance of considering gender in microbiota-related research and suggest that gender-specific management strategies could optimize livestock performance. Future research should explore the role of sex hormones in shaping these microbial differences.

Pregnancy influences on the rumen environment of Angus heifers differing in feed efficiency

With an expected increase in population by 2050, the demand for high-quality protein for human consumption will increase. To improve the sustainability of US cattle production, producers and researchers have historically focused on improving the feed efficiency of steers through improvements in genetics, nutrition, and microbiome management, producing a more marketable beef product. However, without a successful pregnancy, there would be no marketable animal to feed. The objective of this study was to examine the impact of pregnancy on the rumen environment, microbial communities, and the correlation to feed efficiency status in Angus heifers. Utilizing 17 cannulated Angus heifers, feed efficiency status was determined using the GrowSafe 8000 feed intake monitoring system to monitor feed intake for a 70d trial period to calculate residual feed intake. Following the trial, heifers were bred and 40mL rumen fluid and content samples were collected every two weeks during gestation. Metagenomic DNA was extracted from the rumen samples, sequencing libraries were prepared targeting the bacterial V4 region of the 16S rRNA gene, and resultant libraries were sequenced on an Illumina MiSeq. All microbial analyses were conducted in the R environment v2.6.2 where alpha diversity, beta diversity, and differential abundances were determined. Metabolites were identified using ultra high-performance liquid chromatography high resolution mass spectrometry, and Metabolomic Analysis and Visualization Engine was used to select metabolite peaks. Differential abundance analyses using “ANCOMBC” indicated 10 amplicon sequence variants (ASVs), assigned to seven Prevotella and three Succiniclasticum, significantly varied among weeks of gestation (P<0.05). Based on a one-way ANOVA, 90 metabolites were determined significant throughout pregnancy (P<0.05). The 10 metabolites with the highest variable importance of projection scores from a partial least squares discriminant analysis were used to calculate correlations between. Of the 10 ASVs and 10 metabolites, significant correlations with feed efficiency status were found at various time points (P<0.05). The rumen microbiome and its fermentative profile were different at various time points during pregnancy with several correlations to feed efficiency status. Identifying pregnancy-related microbial and metabolite changes may aid producers to anticipate nutritional or management adjustments, ultimately contributing to the sustainability of beef production.

Molecular Innovations Shaping Beak Morphology in Birds.

The beak, a pivotal evolutionary trait characterized by high morphological diversity and plasticity, has enabled birds to survive mass extinction events and subsequently radiate into diverse ecological niches worldwide. This remarkable ecological adaptability underscores the importance of uncovering the molecular mechanisms shaping avian beak morphology, particularly benefiting from the rapidly advancing archives of genomics and epigenomics. We review the latest advancements in understanding how genetic and epigenetic innovations control or regulate beak development and drive beak morphological adaptation and diversification over the past two decades. We conclude with several recommendations for future endeavors, expanding to more bird lineages, with a focus on beak shape and the lower beak, and conducting functional experiments. By directing research efforts toward these aspects and integrating advanced omics techniques, the complex molecular mechanisms involved in avian beak evolution and morphogenesis will be deeply interpreted.

Whether niche changes promote the evolution of species: a case study of Paeonia in Asia and North America

Ecological changes have been observed to promote rates of lineage diversification, yet the precise roles of ecological factors, species evolution, and environmental variability in driving species diversity remain research hot spots. The association between ecological change and lineage diversification, particularly with regard to the size of the time scale, remains poorly understood. To explore whether ecological change facilitates species evolution, we focused on the unique family Paeoniaceae, which encompasses both herbaceous and woody taxa, to investigate the evolutionary rates. As a unique family characterized by a single genus of angiosperms and comprising various climatic types, the ecological niche changes of Paeoniaceae are closely associated with the evolution, making it an ideal model for conducting association analysis. In this study, we integrated the molecular fragments and ecological factors to explore the relationship between species evolution and niche changes in Paeoniaceae. The phylogenetic tree revealed that Paeoniaceae forms a sister relationship with Penthoraceae, Haloragidaceae, Iteaceae, Crassulaceae, and Saxifragaceae, constituting an independent clade based on the positive selection of molecular fragments including two protein-coding genes and eight non-coding regions. The divergence time was estimated to be between 102 and 116 Mya (Million years ago). The phylogenetic tree within Paeonia revealed a clear division into three groups: sections of Paeonia, Moutan, and Onaepia with high support values for each branch based on the ten positive selection of molecular fragments. The rapid rate of evolution observed in Paeonia, about 0-5 Mya. In addition, ecological niche modeling showed that the potential distributions for Paeonia expanded from middle Asia to eastern Asia, and from central North America to the Northern part of North America during the Last Glacial Maximum (LGM) to Mid Holocene (MID) period. This suggests that Paeonia continuously adapted to changing ecological environments over time. Compared to the rate of climatic niche divergence and lineage diversification, the ecological niche of Paeonia underwent significant changes during the period of 3-11 Mya, occurring 5 Mya earlier than the period of evolutionary rate change. These findings offer comprehensive insights into the relationship between niche change and the evolution of species, providing valuable perspectives for further ecological cultivation efforts.

Host genotype and infection status interact to shape microbiomes in Daphnia magna.

Host–bacterial communities (microbiomes) are influenced by a wide range of factors including host genotype and parasite exposure. However, few studies disentangle temporal and host-genotype-specific variation in microbiome response to infection across several host tissues. We experimentally exposed the freshwater crustacean Daphnia magna to its fungal parasite Metschnikowia bicuspidata and characterized changes in host–bacterial communities associated with the parasite's development within the host. We used 16S rRNA gene sequencing to assess bacterial communities of the host (a) 24 h (‘initial parasite exposure’) and (b) 10 days (‘successful infection’) after exposure to a standard dose of M. bicuspidata spores, in host guts, body tissue (excluding guts) and whole individuals. We also investigated whether bacterial community responses to parasite exposure varied by host genotype.Parasite exposure did not immediately alter host gut bacterial communities, but drove host-genotype-specific changes in the bacterial community composition of whole individuals. We validated that these changes were not driven by shifts in bacterial communities of the culturing medium, due to the addition of the parasite spore solution. Successful infection (i.e. the proliferation of M. bicuspidata spores in the host body) reduced alpha diversity and shifted abundance of dominant bacterial orders in the gut. Moreover, it induced a host-genotype-specific changes in body bacterial community composition. Overall, bacterial community responses to parasite exposure and subsequent infection are complex: they occur in a host-genotype-dependent manner, differentially at distinct timepoints after parasite exposure, and in specific host tissue.

Close correlation between sugarcane ratoon decline and rhizosphere ecological factors.

Rhizosphere ecological factors that affect sugarcane ratoons are crucial components in the feedback mechanisms between the sugarcane plant and soil environment. However, systematic investigations on these dynamics are lacking. Therefore, this study investigated the relationship between sugarcane ratoon decline and rhizosphere ecological factors. In first-year sugarcane ratoons, ecological factors such as soil available potassium content, soil nitrogen fixation, and soil peroxidase activity were significantly positively correlated with sugarcane growth (P < 0.05) compared to that of third-year sugarcane ratoons. Significant intergroup disparities in the rhizosphere soil microbial community structure were observed based on different ratoon ages (P < 0.01), while highly significant intergroup differences in endophytic microbial community structure were observed based on a Jaccard distance analysis (P < 0.01). Generalised additive model analysis revealed a significant positive correlation (P < 0.05) between sugarcane growth properties and the alpha diversity of rhizosphere soil bacteria and endophytic bacteria but a predominantly negative correlation (P > 0.05) between the alpha diversity of endophytic fungi and key sugarcane growth indicators. The deterioration of mainly non-microbial ecological factors in rhizosphere soil (P < 0.05) with increasing ratoon age may represent a significant factor contributing to sugarcane ratoon decline. The fungal community significantly impacted soil enzyme activity, while the microbial community indirectly influenced sugarcane yield through its effect on soil enzyme activity. Therefore, endophytic fungi, particularly Ascomycota species, may play a crucial role in sugarcane diseases.

Metagenomics analysis of bacterial community structure from wood- and soil-feeding termites: metabolic pathways and functional structures toward the degradation of lignocellulose and recalcitrant compounds

Some essential information on gut bacterial profiles and their unique contributions to food digestion in wood-feeding termites (WFT) and soil-feeding termites (SFT) is still inadequate. The feeding type of termites is hypothesized to influence their gut bacterial composition and its functionality in degrading lignocellulose or other organic chemicals. This could potentially provide alternative approaches for the degradation of some recalcitrant environmental chemicals. Therefore, metagenomic analysis can be employed to examine the composition and functional profiles of gut bacterial symbionts in WFT and SFT. Based on the metagenomic analysis of the 16S rRNA gene sequences of gut bacterial symbionts in the WFT, Microcerotermes sp., and the SFT, Pericapritermes nitobei, the findings revealed a total of 26 major bacterial phyla, with 18 phyla commonly represented in both termites, albeit in varying abundances. Spirochaetes dominated the bacterial symbionts in Microcerotermes sp. at 55%, followed by Fibrobacters, while Firmicutes dominated the gut bacteria symbionts in P. nitobei at 95%, with Actinobacteria coming in second at 2%. Furthermore, the Shannon and phylogenetic tree diversity indices, as well as the observed operational taxonomic units and Chao 1 richness indices, were all found to be higher in the WFT than in the SFT deduced from the alpha diversity analysis. Based on the principal coordinate analysis, exhibited a significant distance dissimilarity between the gut bacterial symbionts. The results showed that the gut bacterial composition differed significantly between the WFT and SFT. Furthermore, Tax4Fun analysis evaluated bacterial functions, revealing the predominance of carbohydrate metabolism, followed by amino acid metabolism and energy metabolism in both Microcerotermes sp. and P. nitobei termites. The results implicated that bacterial symbionts inhabiting the guts of both termites were actively involved in the degradation of lignocellulose and other recalcitrant compounds.

Repeatable patterns in the distribution of freshwater biodiversity indicators across contrasting landscapes

Abstract Context Freshwater biodiversity is declining at unparalleled rates, but fundamental questions remain over how it is distributed at the spatial scales most relevant for conservation management. Objectives Here, we test the hypothesis that freshwater biodiversity is distributed across standing waterbody types in a pattern that is reproducible across disparate biota and contrasting landscapes, such that conservation efforts can be aligned across landscapes and taxa. Methods We analysed the richness, composition and distribution of macrophytes, molluscs, beetles and odonates from 199 standing waterbodies (lakes, ponds, ditches and canals) nested within UK landscapes with contrasting dominant land use (agricultural, upland and suburban). Results We found a common pattern in the distribution of our biodiversity indicators across waterbody types in all landscapes that was largely repeated across biota; lakes consistently had the highest or equal alpha diversity and supported a greater proportion of the sampled species pool in each landscape (mean = 86%) in comparison to ponds (74%). Landscape-specific waterbody types (ditches and canals) also contributed significantly to the regional species pool (69 and 33% respectively). Each waterbody type contributed uniquely to landscape biodiversity and usually species of conservation concern, rather than simply supporting a subset of ubiquitous species found in lakes. Conclusions Landscape-wide management strategies that encompass multiple habitats and biota should prove advantageous and generalisable. However, our study landscapes suggest that long-term biodiversity conservation should also recognise lakes as a priority for nature recovery, both to minimise further losses and to maintain the largest reservoir of biodiversity.

Continuous planting American ginseng (Panax quinquefolius L.) caused soil acidification and bacterial and fungal communities' changes.

American ginseng is an important herb crop and is widely cultivated in China. However, continuous cropping seriously affects the production of American ginseng, and the reason is still unclear and needs more research. We analyzed the soil microbial alpha diversity and community composition as well as soil physicochemical properties in bulk soils to assess the changes in soil associated with planting American ginseng. The cultivation of American ginseng resulted in a significant decrease in soil pH value. The alpha diversity of soil bacteria and fungi was significantly reduced with the increase of American ginseng planting years. Planting American ginseng also largely altered the community composition of soil bacteria and fungi, in particularly, increased the relative abundance of the pathogenic fungus Fusarium, and reduced the relative abundance of some beneficial microorganisms, such as KD4-96, RB41 and Sphingomonas. Soil acidification, reduction of beneficial taxa and accumulation of fungal pathogens, therefore, may lead to the replantation problem of American ginseng.

Effect of calf separation on gut microbiome and fecal metabolome of mother in the captive Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis).

Social separation, or the absence of social support, can cause physical and psychological health issues. Social separation is crucial for the welfare of the Yangtze finless porpoise (YFP) in captivity because they face many challenges like frequent social separation, noise from visitors, and animal replacement, which can cause psychological and physiological stress. This research is aimed at assessing the potential negative impacts of social separation on the gut microbiome and metabolome of captive YFP, focusing on the potential imbalances caused by mother-calf separation. The study found that social separation did not alter the alpha and beta diversity of the gut microbes but increased the abundance of disease-associated taxa such as Romboutsia, Terrisporobacter, and Clostridium_sensu_stricto_13 in the MC (mother-calf) group while increasing Paeniclostridium and Clostridium_sensu_stricto_1 associated with host health in the MS (mother-separated) group. The fecal metabolome underwent significant changes during social separation, with stress-associated metabolites like kainic acid, phenethylamine glucuronide, and paxilline upregulated in the MC group and host health-associated metabolites like butyric acid, 6-hydroxyhexanoic acid, and fosinopril downregulated in the MS group. In addition, there was a strong association between the fecal microbiome and the metabolome of captive YFPs. The study enhances our comprehension of the detrimental effects of social separation, which result in disruptions in the gut microbiome and fecal metabolome. The study is aimed at introducing a new method for assessing the health and welfare of endangered mammals in captivity.

Bacterial community in fresh fruits and vegetables sold in streets and open-air markets of Dakar, Senegal.

In the context of food transition, the agrifood sector has experienced increasingly strong demand for horticultural products. Fresh fruits and vegetables are mainly vehicles of microorganisms, including pathogens that cause human infections. Food safety and compliance with health standards in the fruits and vegetable value chain are significant concerns and multiple challenges, given the prevalence of foodborne pathologies in Southern countries, particularly in Senegal. This study aimed to describe the bacterial community and assess the microbiological quality of a range of fruits and vegetables sold on street stalls and open-air markets in Dakar, the capital city of Senegal. Samples purchased in seven sites were analyzed to isolate Escherichia coli (E. coli), Salmonella spp. and Vibrio spp. Some primary samples with a positive microbiological culture were subjected to DNA extraction and subsequent metagenomic analysis. A total of 240 fresh fruit and vegetable samples were collected, including lettuce (n = 40), tomatoes (n = 40), mango slices (n = 40), onion slices (n = 40), mint leaves (n = 40), strawberries and grapes (each n = 20). Of these samples, 50.83% (122/240) and 60.41% (145/240) were contaminated with E. coli and Vibrio spp., respectively, while Salmonella was not isolated in any product. E. coli and Vibrio spp. contamination levels, 1.3 103 to 6 106 Colonies Forming Units per gram of sample (CFU/g) and 4.55 102 to 8.73 106CFU/g, respectively, were significantly above the thresholds acceptable for human consumption. The most contaminated samples were lettuce, with a prevalence of 98% (39/40) for E. coli and Vibrio spp. followed by mint leaves with 100% (40/40) and 93% (37/40) of the samples containing E. coli and Vibrio spp. respectively. Out of 46 samples sequenced, the metagenomic analysis revealed high contamination rates for E. coli, Vibrio spp. and Salmonella spp., with 100%, 67.39% and 93.47% of prevalence, respectively. On the other hand, the alpha diversity analysis shows high bacterial diversity in lettuce and mint leaf samples, while the beta diversity analysis highlighted the presence of two major clusters. Our results stress the need for a surveillance system that extends this investigation to a national scale while increasing the number of sampling sites and products analyzed.

Seasonality and interannual variability of an arctic marine time series, IsA

The Arctic is warming twice as fast as anywhere else on the planet, in the European Arctic mainly driven by exalted Atlantic Water inflow. Microbial eukaryotes are diverse and essential to the functioning of marine ecosystems, thus environmental perturbations altering their communities influence the entire ecosystem. To study seasonal and interannual variation and the potential effects of Atlantification, a long-term marine time series has been established in Isfjorden-Adventfjorden (IsA), West Spitsbergen. We here present three years of high-resolution data including hydrography, nutrients, photosynthetic biomass, flow cytometry and community composition of microbial eukaryotes (0.45–10μm, based on Illumina metabarcoding of 18S rDNA and rRNA). The timing, magnitude and species composition of the spring bloom varied interannually, with the more Atlantic spring 2014 being distinctly different from the two other years. A strong recurring seasonal pattern was evident in biodiversity, cell abundances and community composition. Winter communities were characterized by high alpha diversity and very low cell numbers with a dominance of heterotrophic and parasitic taxa. Despite large intra- and interannual differences in communities during the productive time of the year, winter communities were always highly similar, suggesting that the polar night represents a strong environmental forcing that resets the microbial communities.

Aggregate Size Mediated the Changes in Soil Microbial Communities After the Afforestation of a Former Dryland in Northwestern China

Although the afforestation of former arable lands is a common global land-use conversion, its impact on soil microbial communities at the aggregate scale has not been adequately addressed. In this study, soil samples were categorized into large macroaggregates (LM, &gt;2 mm), small macroaggregates (SM, 2–0.25 mm), and microaggregates (MI, &lt;0.25 mm) to assess the changes in microbial composition, diversity, network complexity, and network stability within soil aggregates after the afforestation of a former dryland in northwestern China. The results revealed that afforestation enhanced the relative abundance of Actinobacteriota, Chloroflexi, Ascomycota, and Mortierellomycota within the soil aggregates, suggesting that these phyla may have greater advantages in microbial communities post-afforestation. The Shannon–Wiener and Pielou indices for bacterial communities showed no significant differences between land-use types across all aggregate fractions. However, the alpha diversity of fungal communities within the LM and SM significantly increased after afforestation. Bray–Curtis dissimilarity indices showed that afforestation altered bacterial beta diversity within the LM and MI but had a minimal impact on fungal beta diversity across all three aggregate fractions. The topological features of cross-kingdom microbial co-occurrence networks within the soil aggregates generally exhibited a decreasing trend post-afforestation, indicating a simplification of microbial community structure. The reduced robustness of microbial networks within the LM and SM fractions implies that afforestation also destabilized the structure of microbial communities within the macroaggregates. The composition of the soil microbial communities correlated closely with soil carbon and nitrogen contents, especially within the two macroaggregate fractions. The linkages suggests that improved resource conditions could be a key driver behind the shifts in microbial communities within soil aggregates following afforestation. Our findings indicate that the impact of afforestation on soil microbial ecology can be better understood by soil aggregate fractionation.

A Comparative Analysis of the Ocular Microbiome: Insights into Healthy Eyes and Anophthalmic Sockets

The purpose of this study is to characterize the ocular surface microbiota of patients with an anophthalmic cavity. An eNAT with 1 mL of Liquid Amies Medium was used to collect samples. Microbial DNA from anophthalmic socket and healthy fellow control eye samples was isolated and sequenced. Raw reads were analyzed with GAIA (v 2.02). The richness and Shannon alpha diversity metrics, as well as Bray–Curtis beta diversity and Wilcoxon signed-rank test values, were computed with R packages such as phyloseq, mia, or DESeq2 to allow for microbiome analysis. Principal coordinate analysis (PCoA) was performed using the function plotReducedDim from the R package scater. The different taxonomic profiles were described under the concept of eye community state type (ECST). The microbiomes of both eyes from 25 patients with an anophthalmic cavity were analyzed in this study. While the microbial communities of paired eyes from the same patients showed notable dissimilarity, no consistent patterns emerged when comparing healthy eyes to anophthalmic sockets. Alpha diversity values did not significantly differ between healthy eyes and anophthalmic socket samples, though there was considerable variability within each group. Notably, anophthalmic socket samples generally exhibited lower abundances of genera such as Staphylococcus, Enterococcus, Paenibacillus, and Sediminibacterium compared to their healthy counterparts. Microbial variability between healthy eyes and anophthalmic sockets may be due to anatomical differences. Further research is needed to determine whether patients without anophthalmic sockets exhibit similar microbiome patterns in both eyes.

Immunoglobulin-coating patterns reveal altered humoral responses to gut bacteria in pediatric cow milk allergies.

Pediatric cow milk allergies (CMA) can occur in immunoglobulin (Ig) E and non-IgE-mediated forms. Unlike IgE-mediated allergies, the mechanisms of disease pathogenesis in non-IgE-mediated food allergy and an association with microbiome has not been well established. Previous studies have identified the presence of altered humoral responses to gut bacteria in IgE mediated allergies. Here, we analyzed IgA, IgE and IgG responses to gut bacteria in subjects with either IgE or non-IgE mediated CMA to identify relative proportions of Ig-coated bacteria and characterize unique disease specific microbial signatures. Multi-parametric flow cytometry analysis was used to identify IgA, IgE and IgG responses to gut bacteria in CMA patients. Cell sorting of Ig coated gut bacteria was subsequently performed followed by high throughput 16S rRNA gene sequencing and specific patterns of humoral responses to gut bacteria assessed in each study group. We identified significant alterations in IgA and IgG gut bacterial coating patterns in CMA subjects. Proportions of IgA-coated bacteria were decreased in IgE mediated CMA subjects without atopic dermatitis (ALL) and non-IgE mediated CMA subjects (ENP), compared to healthy controls (CON). In comparison, IgG-coated bacteria was significantly elevated in CMA subjects with atopic dermatitis (AD). Alpha and beta diversities displayed significant differences in IgA-, IgE-, and IgG-coated bacteria in AD and ENP groups. Significant differences in bacteria coated by IgA, IgE and IgG were detected at Phyla, Genus and Species levels and associated bacterial dysbiosis in IgE and non-IgE mediated allergies were identified. Linear discriminant analysis (LDA) effect size (LEFse) revealed unique disease associated bacterial signatures, including several pathogenic bacteria namely Bacteroides fragilis, Ruminococcus gnavus, Eubacterium dolichum, Fusobacterium, Clostridium neonatale and Robinsoniella peoriensis. Receiver operating characteristic curve analysis confirmed the efficiency of using the bacterial signatures identified as biomarkers for disease. Altered IgA and IgG responses to gut bacteria were identified in CMA subjects. The disease-specific responses were associated with alterations in bacterial diversity and concomitant dysbiosis of Ig-coated bacteria in IgE-mediated and non-IgE-mediated CMA pediatric subjects. The identification of pathogenic bacteria uniquely associated with different classes of allergic disease indicates a role of these bacteria in driving disease-specific pathological phenotypes.

Effects of snake fungal disease (ophidiomycosis) on the skin microbiome across two major experimental scales.

Emerging infectious diseases are increasingly recognized as a significant threat to global biodiversity conservation. Elucidating the relationship between pathogens and the host microbiome could lead to novel approaches for mitigating disease impacts. Pathogens can alter the host microbiome by inducing dysbiosis, an ecological state characterized by a reduction in bacterial alpha diversity, an increase in pathobionts, or a shift in beta diversity. We used the snake fungal disease (SFD;ophidiomycosis), system to examine how an emerging pathogen may induce dysbiosis across two experimental scales. We used quantitative polymerase chain reaction, bacterial amplicon sequencing, and a deep learning neural network to characterize the skin microbiome of free-ranging snakes across a broad phylogenetic and spatial extent. Habitat suitability models were used to find variables associated with fungal presence on the landscape. We also conducted a laboratory study of northern watersnakes to examine temporal changes in the skin microbiome following inoculation with Ophidiomyces ophidiicola. Patterns characteristic of dysbiosis were found at both scales, as were nonlinear changes in alpha and alterations in beta diversity, although structural-level and dispersion changes differed between field and laboratory contexts. The neural network was far more accurate (99.8% positive predictive value [PPV]) in predicting disease state than other analytic techniques (36.4% PPV). The genus Pseudomonas was characteristic of disease-negative microbiomes, whereas, positive snakes were characterized by the pathobionts Chryseobacterium, Paracoccus, and Sphingobacterium. Geographic regions suitable for O. ophidiicola had high pathogen loads (>0.66 maximum sensitivity+specificity). We found that pathogen-induced dysbiosis of the microbiome followed predictable trends, that disease state could be classified with neural network analyses, and that habitat suitability models predicted habitat for the SFD pathogen.