Microbiome Response Research Articles

Rumen microbiome response to sustained release mineral bolus supplement with low- and high-quality forages

IntroductionLimited forage quantity and quality are challenges faced in livestock production systems in semi-arid rangelands of the western United States, particularly when livestock face stressors such as cold weather or have increased nutritional requirements such as during pregnancy and lactation. To meet livestock nutrient requirements, producers frequently provide supplemental nutrition, however there is limited knowledge regarding the effects of these practices on the rumen microbiome in these environments.MethodsA study was conducted to evaluate changes in the rumen microbiome in response to high- and low- quality forage with sustained release mineral boluses. The study consisted of 16 ruminally-cannulated 2–3-year-old black angus cows fed high quality grass alfalfa hay or low-quality grass hay with a 90 or 180 day sustained release mineral bolus. Rumen samples were collected pre-feeding and 8 hours post feeding and bacterial 16S rRNA gene amplicons were sequenced from the rumen fluid.ResultsAlpha diversity as measured by Shannon’s diversity index decreased significantly over time (p<0.01) and averaged 5.6 pre-feeding and 5.4 post- feeding and was not significantly different between high- and low-quality forages or between mineral bolus types (p>0.05). Principal coordinates analysis (PCoA) of the Bray-Curtis dissimilarity matrix showed distinct grouping by feed quality and time but not by mineral bolus type. Bacteroidetes and Firmicutes were the dominant phyla in all treatments and significant increases (p<0.05) in the relative abundance of the family Lachnospiraceae and the genus Prevotella were observed in high quality forage diets. Rumen VFA and NH3-N concentrations were also strongly associated with the high-quality forage diet. Predictive functional profiling indicated that functions associated with methanogenesis were negatively correlated with feed quality.DiscussionThe results of this study suggest that mineral bolus type is unlikely to affect rumen bacterial community structure or function while forage quality can significantly alter community structure and predicted functions associated with methanogenesis and VFA production.

A Diet Enriched with Lacticaseibacillus rhamnosus HN001 and Milk Fat Globule Membrane Alters the Gut Microbiota and Decreases Amygdala GABA a Receptor Expression in Stress-Sensitive Rats

Brain signalling pathways involved in subclinical anxiety and depressed mood can be modulated via the gut brain axis (GBA), providing the potential for diet and dietary components to affect mood. We investigated behavioural, physiological and gut microbiome responses to the Lacticaseibacillus rhamnosus strain HN001 (LactoB HN001™), which has been shown to reduce postpartum anxiety and depression, and a milk fat globule membrane-enriched product, Lipid 70 (SurestartTM MFGM Lipid 70), which has been implicated in memory in stress-susceptible Wistar Kyoto rats. We examined behaviour in the open field, elevated plus maze and novel object recognition tests in conjunction with the expression of host genes in neuro-signalling pathways, and we also assessed brain lipidomics. Treatment-induced alterations in the caecal microbiome and short-chain fatty acid (SCFA) profiles were also assessed. Neither ingredient induced behavioural changes or altered the brain lipidome (separately or when combined). However, with regard to brain gene expression, the L. rhamnosus HN001 + Lipid 70 combination produced a synergistic effect, reducing GABAA subunit expression in the amygdala (Gabre, Gat3, Gabrg1) and hippocampus (Gabrd). Treatment with L. rhamnosus HN001 alone altered expression of the metabotropic glutamate receptor (Grm4) in the amygdala but produced only minor changes in gut microbiota composition. In contrast, Lipid 70 alone did not alter brain gene expression but produced a significant shift in the gut microbiota profile. Under the conditions used, there was no observed effect on rat behaviour for the ingredient combination. However, the enhancement of brain gene expression by L. rhamnosus HN001 + Lipid 70 implicates synergistic actions on region-specific neural pathways associated with fear, anxiety, depression and memory. A significant shift in the gut microbiota profile also occurred that was mainly attributable to Lipid 70.

Revealing proteome-level functional redundancy in the human gut microbiome using ultra-deep metaproteomics

Functional redundancy is a key ecosystem property representing the fact that different taxa contribute to an ecosystem in similar ways through the expression of redundant functions. The redundancy of potential functions (or genome-level functional redundancy {{{{{{rm{FR}}}}}}}_{g}) of human microbiomes has been recently quantified using metagenomics data. Yet, the redundancy of expressed functions in the human microbiome has never been quantitatively explored. Here, we present an approach to quantify the proteome-level functional redundancy {{{{{{rm{FR}}}}}}}_{p} in the human gut microbiome using metaproteomics. Ultra-deep metaproteomics reveals high proteome-level functional redundancy and high nestedness in the human gut proteomic content networks (i.e., the bipartite graphs connecting taxa to functions). We find that the nested topology of proteomic content networks and relatively small functional distances between proteomes of certain pairs of taxa together contribute to high {{{{{{rm{FR}}}}}}}_{p} in the human gut microbiome. As a metric comprehensively incorporating the factors of presence/absence of each function, protein abundances of each function and biomass of each taxon, {{{{{{rm{FR}}}}}}}_{p} outcompetes diversity indices in detecting significant microbiome responses to environmental factors, including individuality, biogeography, xenobiotics, and disease. We show that gut inflammation and exposure to specific xenobiotics can significantly diminish the {{{{{{rm{FR}}}}}}}_{p} with no significant change in taxonomic diversity.

Responses of gut microbiomes to commercial polyester polymer biodegradation in Tenebrio molitor Larvae

Polyethylene terephthalate (PET) is a mass-produced fossil-based plastic polymer that contributes to catastrophic levels of plastic pollution. Here we demonstrated that Tenebrio molitor (mealworms) was capable of rapidly biodegrading two commercial PET resins (microplastics) with respective weight-average molecular weight (Mw) of 39.33 and 29.43 kDa and crystallinity of 22.8 ± 3.06% and 18 ± 2.25%, resulting in an average mass reduction of 71.03% and 73.28% after passage of their digestive tract, and respective decrease by 9.22% and 11.36% in Mw of residual PET polymer in egested frass. Sequencing of 16 S rRNA gene amplicons of gut microbial communities showed that dominant bacterial genera were enriched and associated with PET degradation. Also, PICRUSt prediction exhibited that oxidases (monooxygenases and dioxygenases), hydrolases (cutinase, carboxylesterase and chitinase), and PET metabolic enzymes, and chemotaxis related functions were up-regulated in the PET-fed larvae. Additionally, metabolite analyses revealed that PET uptake caused alterations of stress response and plastic degradation related pathways, and lipid metabolism pathways in the T. molitor larvae could be reprogrammed when the larvae fed on PET. This study provides new insights into gut microbial community adaptation to PET diet under nutritional stress (especially nitrogen deficiency) and its contribution to PET degradation.

Curated and harmonized gut microbiome 16S rRNA amplicon data from dietary fiber intervention studies in humans

Next generation amplicon sequencing has created a plethora of data from human microbiomes. The accessibility to this scientific data and its corresponding metadata is important for its reuse, to allow for new discoveries, verification of published results, and serving as path for reproducibility. Dietary fiber consumption has been associated with a variety of health benefits that are thought to be mediated by gut microbiota. To enable direct comparisons of the response of the gut microbiome to fiber, we obtained 16S rRNA sequencing data and its corresponding metadata from 11 fiber intervention studies for a total of 2,368 samples. We provide curated and pre-processed genetic data and common metadata for comparison across the different studies.

Legacy effects of intensified drought on the soil microbiome in a mesic grassland

AbstractThe soil microbiome response to global change drivers remains largely unclassified, with current studies showing contrasting results to several global change drivers. One such driver, drought, is increasing in severity and frequency due to climate change. Further, legacy effects, or long‐lasting impacts after drought has subsided, could have lasting impacts on the soil microbiome with important consequences for ecosystem functioning. Thus, our study aimed to understand how the soil microbiome responds after a severe, prolonged drought and whether legacy effects persist post‐drought. We measured soil microbial community response in a mesic grassland for two years after a four‐year experimental drought in a native tallgrass prairie. The experimental drought was imposed either (1) chronically by reducing each growing season rainfall event by 66% or (2) intensely by completely eliminating growing season rainfall until an ~45% reduction in mean annual rainfall (climatic average) was achieved. The bacterial community showed no legacies in the first season post‐drought in response to either chronic or intense drought but showed an increased abundance of Verrucomicrobia and decreased richness in both treatments in the second growing season after the drought treatments ended. In the first and second post‐drought growing seasons, we found small differences in beta diversity between the control and intense drought treatment for fungal communities but not for the chronic drought treatment. Further, we found that the two main phyla of fungi, Ascomycota and Basidiomycota, showed reduced relative abundance post‐drought in the intense drought treatment. Overall, few legacies in soil microbial communities persisted after a four‐year experimentally induced drought. However, our results show that the nature of the drought—chronic versus intense—can differentially impact fungal versus bacterial short‐term legacies. These results suggest that the soil microbiome is for the most part drought resistant (responds little during drought) and/or resilient (quickly recovers post‐drought, since a study at the same site found that drought impacted the bacterial community) in this mesic grassland.

Elevated [CO2] enhances soil respiration and AMF abundance in a semiarid peanut agroecosystem

Rising atmospheric carbon dioxide [CO2] is a main climate change driver, and soil respiration is the most relevant contributor to ecosystem respiration. However, the soil microbiome and respiration responses of semiarid agroecosystems under elevated [CO2] (eCO2) conditions must be better understood. In particular, peanut agroecosystems host rhizobia and arbuscular mycorrhizal fungi (AMF) associations. Here, we sought to address the following questions: a) Does eCO2 conditions (650 µmol CO2 m−2 s−1, +250 µmol CO2 m−2 s−1, aCO2, control) alter soil chemical properties, soil microbial community size and composition, soil respiration, and β-Glucosidase activity? b) Are these responses influenced by transient water deficit periods? We conducted this study in a typical West Texas semiarid region (no well-watered treatment and drought was not an experimental factor) during two consecutive growing seasons (May-Oct). We induced the atmospheric CO2 enrichment using field-installed Canopy Evapotranspiration and Assimilation (CETA) systems. Our results showed no consistent significant changes in soil moisture, C: N ratio, total soil microbial EL-FAME abundance, or β-Glucosidase activity. However, we found that eCO2 increased soil temperature (+1 °C), AMF abundance (EL-FAME marker, +49%), and soil respiration (+82%). Our findings suggest that in future semiarid climates, peanut agroecosystems may experience: 1) increased soil metabolic activity as a result of increased autotrophic respiration; 2) increased AMF, which could further facilitate plant nutrient and water uptake; and 3) minimal change in the total size of the microbial community and C cycling enzyme activity during the growing season. In this manuscript, we demonstrated that soil respiration and temperature could be indicators of ecosystem productivity and climate feedback. Furthermore, soil organic carbon and AMF were good indicators of poor nutrient soil ecosystem transitional health across well-watered and water-deficit cycles. This study will increase our understanding of how these changes will affect soil ecology and climate feedback and will provide new insight into the peanut agroecosystem carbon source/sink functioning and productivity in future climates.

Hawaiian coral holobionts reveal algal and prokaryotic host specificity, intraspecific variability in bleaching resistance, and common interspecific microbial consortia modulating thermal stress responses

Historically, Hawai‘i had few massive coral bleaching events, until two consecutive heatwaves in 2014–2015. Consequent mortality and thermal stress were observed in Kāne‘ohe Bay (O‘ahu). The two most dominant local species exhibited a phenotypic dichotomy of either bleaching resistance or susceptibility (Montipora capitata and Porites compressa), while the third predominant species (Pocillopora acuta) was broadly susceptible to bleaching. In order to survey shifts in coral microbiomes during bleaching and recovery, 50 colonies were tagged and periodically monitored. Metabarcoding of three genetic markers (16S rRNA gene ITS1 and ITS2) followed by compositional approaches for community structure analysis, differential abundance and correlations for longitudinal data were used to temporally compare Bacteria/Archaea, Fungi and Symbiodiniaceae dynamics. P. compressa corals recovered faster than P. acuta and Montipora capitata. Prokaryotic and algal communities were majorly shaped by host species, and had no apparent pattern of temporal acclimatization. Symbiodiniaceae signatures were identified at the colony scale, and were often related to bleaching susceptibility. Bacterial compositions were practically constant between bleaching phenotypes, and more diverse in P. acuta and M. capitata. P. compressa's prokaryotic community was dominated by a single bacterium. Compositional approaches (via microbial balances) allowed the identification of fine-scale differences in the abundance of a consortium of microbes, driving changes by bleaching susceptibility and time across all hosts. The three major coral reef founder-species in Kāne‘ohe Bay revealed different phenotypic and microbiome responses after 2014–2015 heatwaves. It is difficult to forecast, a more successful strategy towards future scenarios of global warming. Differentially abundant microbial taxa across time and/or bleaching susceptibility were broadly shared among all hosts, suggesting that locally, the same microbes may modulate stress responses in sympatric coral species. Our study highlights the potential of investigating microbial balances to identify fine-scale microbiome changes, serving as local diagnostic tools of coral reef fitness.

Highly controlled nutritional interventions uncover defined immune and microbiome responses in human.

Abstract Previous studies linked diet to numerous physiological functions including the control of the immune system and composition of the microbiome. Here, we report the first human study using a well-controlled cross-over experiment of a vegan, low-fat diet and a ketogenic, low-carbohydrate diet in a clinical setup. We assess the impact of these dietary interventions via complementary approaches including protein expression via SOMAScan assay, gene expression via RNA-seq, cell population composition via flow cytometry, and metabolomics in the blood, as well as fecal microbiome composition via metagenomics sequencing. Based on functional enrichment analysis of RNA-seq, a vegan diet had a more pronounced impact on the innate immune system than a ketogenic diet as evidenced by enhanced monocyte response, immune activation and upregulation of TNFa, INFa, and INFg responses. On the other hand, a ketogenic diet had a more pronounced impact on B and T cell response. Proteomic analysis uncovers a stronger response to the ketogenic diet in female compared to male participants. Finally, a ketogenic diet alters the microbiome composition significantly more than the vegan diet with enrichment in many microbes including bile-tolerant gut Bacteroidestaxa. Pathway analysis in the microbiome and metabolomics data showed changes in amino acid biosynthesis pathways, with many pathways down-regulated in the ketogenic diet. Together this study represents the first comprehensive multidimensional exploration of how diet can impact the immune system and microbiome in human.

19P Tumor-associated microbiome composition and response to neoadjuvant chemotherapy (NACT) in early triple-negative breast cancer (TNBC)

19P Tumor-associated microbiome composition and response to neoadjuvant chemotherapy (NACT) in early triple-negative breast cancer (TNBC)

The Gut Microbiome Responds Progressively to Fat and/or Sugar-Rich Diets and Is Differentially Modified by Dietary Fat and Sugar.

Describing diet-related effects on the gut microbiome is essential for understanding its interactions with fat and/or sugar-rich diets to promote obesity-related metabolic diseases. Here, we sequenced the V3-V4 hypervariable region of the bacterial 16S rRNA gene to study the composition and dynamics of the gut microbiome of adult mice fed diets rich in fat and/or sugar, at 9 and 18 weeks of diet. Under high-fat, high-sugar diet, the abundances of Tuzzerella and Anaerovorax were transiently increased at 9 weeks, while Lactobacillus remained elevated at 9 and 18 weeks. The same diet decreased the abundances of Akkermansia, Paludicola, Eisenbergiella, and Butyricicoccus at 9 and 18 weeks, while Intestinimonas and UCG-009 of the Butyricicoccaceae family responded only at 18 weeks. The high-fat diet decreased the abundances of UBA1819 at 9 weeks, and Gastranaerophilales, Clostridia UCG-014, and ASF356 at 9 and 18 weeks. Those of Marvinbryantia, Harryflintia, Alistipes, Blautia, Lachnospiraceae A2, Eubacterium coprostanoligenes group, and Eubacterium brachy group were lowered only at 18 weeks. Interestingly, these genera were not sensitive to the high-sugar diet. The mouse gut microbiome was differentially affected by diets rich in fat or fat and sugar. The differences observed at 9 and 18 weeks indicate a progressive microbiome response.

Structure of the river sediment microbiomes impacted by anthropogenic land uses, environmental and spatial variations

River sediments are impacted by anthropogenic land uses since they are the major sinks of pollutants. Sediment microbial communities play vital roles in the degradation of toxic compounds and the recycling of nutrients, sustaining healthy aquatic ecosystems. However, sediment microbiomes impacted by both anthropogenic and natural disturbances are not well documented. This study investigated the dynamics of sediment microbiomes in response to major anthropogenic land uses, environmental, and spatial factors across 25 locations along the Ganh Hao river in Vietnam, using high-throughput sequencing targeting the V3–V4 regions of the 16S rRNA gene. The sediment microbiomes were exclusively dominated by Proteobacteria (59–79%). Microbial taxa associated with shrimp farms, a major land use, were koll13, GCA004, Piscirickettsiaceae, Marinicellaceae, and Desulfobulbaceae. The resulting variation partitioning, based on CCA, indicated that spatial factors highly influenced the microbial profile and explained 41.8% of the microbial variation. However, the variation in sediment microbiomes was largely impacted by a combination of environmental factors (i.e., As, Pb and Cu concentrations, pH and EC) and the presence of shrimp farms which, together with spatial variation, explained 77.4% of the microbial variation. Overall, this study provides insights into the spatial structure of river sediment microbiomes and provides the biological signature of sediment microbiome in response to the major anthropogenic land use and seawater intrusion.

Optimizing SCND with carbon-rich hydrolysates from typical organic wastes: Material composition, augmentation performance, microbiome response, and life cycle impact

The rapid growth of production and consumption has led to severe environmental pollution, creating a major challenge to achieving the United Nations' sustainable development goals (SDGs). To address it, recycling of organic wastes into value-added products is a possible solution. In this work, four typical organic wastes including sewage sludge (SS), chicken manure (CM), food waste (FW), and corn straw (CS) were employed to produce hydrolysates augmenting shortcut nitrification-denitrification (SCND) for nitrogen depletion in wastewater. The hydrolysates were carbon-rich, with total COD (TCOD), soluble COD (SCOD), and volatile fatty acids (VFA) concentrations ranging from 32.5 to 102.7, 5.7 to 48.4, and 2.0–16.5 mg/L, respectively. The most effective nitrogen depletion was obtained in units supplemented with CM and FW hydrolysates, which had reduced average NH3–N concentrations and near-zero TN removal failure rates under legal requirements. The microbial community analysis demonstrated that various functional bacteria from phylum to genus level were detected in all scenarios, which was corroborated by abundant genetic functions involved in nitrogen metabolism. Further, life cycle assessment revealed negative environmental impact on all categories, with an exception of eutrophication potential (EP) with negative values (∼−0.04 kg Phosphate eq.), allowing positive net environmental benefit (NEB). Operational cost analysis revealed that CM and FW are more effective but costlier than SS and CS. Together, these results indicate that, after hydrolysis, organic wastes can be efficient stimulant augmenting SCND performance for nitrogen depletion in wastewater, benefiting the overall environmental impact.

Rapid differentiation of soil and root microbiomes in response to plant composition and biodiversity in the field

Research suggests that microbiomes play a major role in structuring plant communities and influencing ecosystem processes, however, the relative roles and strength of change of microbial components have not been identified. We measured the response of fungal, arbuscular mycorrhizal fungal (AMF), bacteria, and oomycete composition 4 months after planting of field plots that varied in plant composition and diversity. Plots were planted using 18 prairie plant species from three plant families (Poaceae, Fabaceae, and Asteraceae) in monoculture, 2, 3, or 6 species richness mixtures and either species within multiple families or one family. Soil cores were collected and homogenized per plot and DNA were extracted from soil and roots of each plot. We found that all microbial groups responded to the planting design, indicating rapid microbiome response to plant composition. Fungal pathogen communities were strongly affected by plant diversity. We identified OTUs from genera of putatively pathogenic fungi that increased with plant family, indicating likely pathogen specificity. Bacteria were strongly differentiated by plant family in roots but not soil. Fungal pathogen diversity increased with planted species richness, while oomycete diversity, as well as bacterial diversity in roots, decreased. AMF differentiation in roots was detected with individual plant species, but not plant family or richness. Fungal saprotroph composition differentiated between plant family composition in plots, providing evidence for decomposer home-field advantage. The observed patterns are consistent with rapid microbiome differentiation with plant composition, which could generate rapid feedbacks on plant growth in the field, thereby potentially influencing plant community structure, and influence ecosystem processes. These findings highlight the importance of native microbial inoculation in restoration.

The Role of TGF-β, Activin and Follistatin in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory condition predominantly affecting the gastrointestinal (GI) tract. An increasing prevalence of IBD has been observed globally. The pathogenesis of IBD includes a complex interplay between the intestinal microbiome, diet, genetic factors and immune responses. The consequent imbalance of inflammatory mediators ultimately leads to intestinal mucosal damage and defective repair. Growth factors, given their specific roles in maintaining the homeostasis and integrity of the intestinal epithelium, are of particular interest in the setting of IBD. Furthermore, direct targeting of growth factor signalling pathways involved in the regeneration of the damaged epithelium and the regulation of inflammation could be considered as therapeutic options for individuals with IBD. Several members of the transforming growth factor (TGF)-β superfamily, particularly TGF-β, activin and follistatin, are key candidates as they exhibit various roles in inflammatory processes and contribute to maintenance and homeostasis in the GI tract. This article aimed firstly to review the events involved in the pathogenesis of IBD with particular emphasis on TGF-β, activin and follistatin and secondly to outline the potential role of therapeutic manipulation of these pathways.

Integrated Microbiome and Metabolomic Analysis Reveal Responses of Rhizosphere Bacterial Communities and Root exudate Composition to Drought and Genotype in Rice (Oryza sativa L.)

BackgroundAs climate change events become more frequent, drought is an increasing threat to agricultural production and food security. Crop rhizosphere microbiome and root exudates are critical regulators for drought adaptation, yet our understanding on the rhizosphere bacterial communities and root exudate composition as affected by drought stress is far from complete. In this study, we performed 16S rRNA gene amplicon sequencing and widely targeted metabolomic analysis of rhizosphere soil and root exudates from two contrasting rice genotypes (Nipponbare and Luodao 998) exposed to drought stress.ResultsA reduction in plant phenotypes was observed under drought, and the inhibition was greater for roots than for shoots. Additionally, drought exerted a negligible effect on the alpha diversity of rhizosphere bacterial communities, but obviously altered their composition. In particular, drought led to a significant enrichment of Actinobacteria but a decrease in Firmicutes. We also found that abscisic acid in root exudates was clearly higher under drought, whereas lower jasmonic acid and L-cystine concentrations. As for plant genotypes, variations in plant traits of the drought-tolerant genotype Luodao 998 after drought were smaller than those of Nipponbare. Interestingly, drought triggered an increase in Bacillus, as well as an upregulation of most organic acids and a downregulation of all amino acids in Luodao 998. Notably, both Procrustes analysis and Mantel test demonstrated that rhizosphere microbiome and root exudate metabolomic profiles were highly correlated. A number of differentially abundant genera responded to drought and genotype, including Streptomyces, Bacillus and some members of Actinobacteria, were significantly associated with organic acid and amino acid contents in root exudates. Further soil incubation experiments showed that Streptomyces was regulated by abscisic acid and jasmonic acid under drought.ConclusionsOur results reveal that both drought and genotype drive changes in the compositions of rice rhizosphere bacterial communities and root exudates under the greenhouse condition, and that organic acid exudation and suppression of amino acid exudation to select specific rhizosphere bacterial communities may be an important strategy for rice to cope with drought. These findings have important implications for improving the adaptability of rice to drought from the perspective of plant–microbe interactions.

Decreasing lactate input for cost-effective sulfidogenic metal removal in sulfate-rich effluents: Mechanistic insights from (bio)chemical kinetics to microbiome response

High material cost is the biggest barrier for the industrial use of low-molecular-weight organics (i.e. lactate) as external carbon and electron source for sulfidogenic metal removal in sulfate-rich effluents. This study aims to provide mechanistic evidence from kinetics to microbiome analysis by batch modeling to support the possibility of decreasing the lactate input to achieve cost-effective application. The results showed that gradient COD/SO42− ratios at a low level had promising treatment performance, reaching neutralized pH with nearly total elimination of COD (91%–99%), SO42− (85%–99%), metals (80%–99%) including Cu, Zn, and Mn. First-order kinetics exhibited the best fit (R2 = 0.81–0.98) to (bio)chemical reactions, and the simulation results revealed that higher COD/SO42− accelerated the reaction rate of SO42− and COD but not suitable to that of metals. On the other hand, we found that the decreasing COD/SO42− ratio increased average path distance but decreased clustering coefficient and heterogeneity in microbial interaction network. Genetic prediction found that the sulfate-reduction-related functions were significantly correlated with the reaction kinetics changed with COD/SO42− ratios. Our study, combining reaction kinetics with microbiome analysis, demonstrates that the use of lactate as a carbon source under low COD/SO42− ratios entails significant efficiency of metal removal in sulfate-rich effluent using SRB-based technology. However, further studies should be carried out, including parameter-driven optimization and life cycle assessments are necessary, for its practical application.

Bioaerosol nexus of air quality, climate system and human health

Aerosols of biological origins, known as bioaerosols, in addition to having the aerosol properties, have those of a living system that offers them some enabling functionalities. From science to technology, visible progress around the world has been made in bioaerosol field before and especially during the COVID-19 pandemic. Here the roles of bioaerosol across various disciplines, including air quality, climate and human health are highlighted and appreciated in light of Anthropocene and one health concept. In particular, we recognized the importance of aerobiology under haze air pollution, allergenic pollen and bioaerosol involvement in infectious and inflammation-related non-communicable diseases. Future interdisciplinary studies focusing on the chemical and biological process of microorganisms in air, airborne transmission of emerging pathogens and allergens and the association between bioaerosol exposure and the development and variations of human microbiome and immune response are needed to elucidate the interactions of bioaerosols with the earth system.

Deciphering Gut Microbiome Responses upon Microplastic Exposure via Integrating Metagenomics and Activity-Based Metabolomics.

Perturbations of the gut microbiome are often intertwined with the onset and development of diverse metabolic diseases. It has been suggested that gut microbiome perturbation could be a potential mechanism through which environmental chemical exposure induces or exacerbates human diseases. Microplastic pollution, an emerging environmental issue, has received ever increasing attention in recent years. However, interactions between microplastic exposure and the gut microbiota remain elusive. This study aimed to decipher the responses of the gut microbiome upon microplastic polystyrene (MP) exposure by integrating 16S rRNA high-throughput sequencing with metabolomic profiling techniques using a C57BL/6 mouse model. The results indicated that MP exposure significantly perturbed aspects of the gut microbiota, including its composition, diversity, and functional pathways that are involved in xenobiotic metabolism. A distinct metabolite profile was observed in mice with MP exposure, which probably resulted from changes in gut bacterial composition. Specifically, untargeted metabolomics revealed that levels of metabolites associated with cholesterol metabolism, primary and secondary bile acid biosynthesis, and taurine and hypotaurine metabolism were changed significantly. Targeted approaches indicated significant perturbation with respect to the levels of short-chain fatty acids derived from the gut microbiota. This study can provide evidence for the missing link in understanding the mechanisms behind the toxic effects of microplastics.

Plant sexual variation modulates rhizospheric nutrient processes through the soil microbiome response to drought and rewetting in Populus cathayana

Plant sexual variation modulates rhizospheric nutrient processes through the soil microbiome response to drought and rewetting in Populus cathayana