Changes In Microbial Composition Research Articles

Characteristics of Semiconducting Minerals Affects Microbial Communities in Purple Soils

Purple soil is rich in semiconducting minerals, but the impact of these minerals on soil properties and associated microbiome assemblages has received little attention. To better understand the influence of semiconducting minerals in soils, samples were collected from 4 soil classifications, including purple soil, siltstone, farmland, and new formed soil. Goethite was the main semiconducting mineral in purple soil followed by rutile and birnessite, while for siltstone, rutile was the major semiconducting mineral. Proteobacteria (77.77–98.56%) was the most prevalent phylum among all samples, with the second most abundant phylum being Cyanobacteria (purple soil and farmland) and Firmicutes (siltstone and new formed soil). According to the average path length in network analysis, purple soil showed higher species segregation, which suggested purple soil was potentially more susceptible to external interference than the other types. The relationship between microbes may be synergistic due to the positive links between microbial phyla. Rutile affected microbial composition to the greatest extent, accounting for 13.66% of the total variation in microbial assembly, while goethite (r= –0.0947) and birnessite (r = 0.0215) content were also associated with changes in microbial composition. These results demonstrated that semiconducting minerals affected the structure and potential energy utilization of soil microbial communities.

Sexual behavior is linked to changes in gut microbiome and systemic inflammation that lead to HIV-1 infection in men who have sex with men

Pathogenic changes in gut microbial composition precede the onset of HIV-1 infection in men who have sex with men (MSM). This process is associated with increased levels of systemic inflammatory biomarkers and risk for AIDS development. Using mediation analysis framework, in this report we link the effects of unprotected receptive intercourse among MSM prior to primary HIV-1 infection to higher levels of proinflammatory cytokines sCD14 and sCD163 in plasma and a significant decrease in the abundance of A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., and Odoribacter spp., and a potential increase in the abundance of Dehalobacterium spp. and Methanobrevibacter spp. in stools of MSM with the highest number of sexual partners. These differences in microbiota, together with a reduction in the pairwise correlations among commensal and short-chain fatty acid-producing bacteria with a number of sexual partners, support an increase in gut dysbiosis with the number of sexual partners. These results demonstrate the interconnectedness of sexual behavior, immune response, and microbiota composition, notably among MSM participating in high-risk sexual behaviors.

Inflammation mediated by gut microbiome alterations promotes lung cancer development and an immunosuppressed tumor microenvironment.

Accumulating evidence indicates that the gut microbiome influences cancer progression and therapy. We recently showed that progressive changes in gut microbial diversity and composition are closely associated with tobacco-associated lung adenocarcinoma (LUAD) in a human-relevant mouse model. Furthermore, we demonstrated that the loss of the antimicrobial protein Lcn2 in these mice, exacerbates pro-tumor inflammatory phenotypes while further reducing microbial diversity. Yet, how gut microbiome alterations impinge on LUAD development remains poorly understood. Here, we investigated the role of gut microbiome changes in LUAD development using fecal microbiota transfer and delineated a pathway by which gut microbiome alterations incurred by loss of Lcn2 fostered the proliferation of pro-inflammatory bacteria of the genus Alistipes, triggering gut inflammation. This inflammation propagated systemically, exerting immunosuppression within the tumor microenvironment, augmenting tumor growth through an IL-6-dependent mechanism and dampening response to immunotherapy. Corroborating our preclinical findings, we found that patients with LUAD with a higher relative abundance of Alistipes species in the gut showed diminished response to neoadjuvant immunotherapy. These insights reveal the role of microbiome-induced inflammation in LUAD and present new potential targets for interception and therapy.

Predicting how varying moisture conditions impact the microbiome of dust collected from the International Space Station

BackgroundThe commercialization of space travel will soon lead to many more people living and working in unique built environments similar to the International Space Station, which is a specialized closed environment that contains its own indoor microbiome. Unintended microbial growth can occur in these environments as in buildings on Earth from elevated moisture, such as from a temporary ventilation system failure. This growth can drive negative health outcomes and degrade building materials. We need a predictive approach for modeling microbial growth in these critical indoor spaces.ResultsHere, we demonstrate that even short exposures to varying elevated relative humidity can facilitate rapid microbial growth and microbial community composition changes in dust from spacecraft. We modeled fungal growth in dust from the International Space Station using the time-of-wetness framework with activation and deactivation limited growth occurring at 85% and 100% relative humidity, respectively. Fungal concentrations ranged from an average of 4.4 × 106 spore equivalents per milligram of dust in original dust with no exposure to relative humidity to up to 2.1 × 1010 when exposed to 100% relative humidity for 2 weeks. As relative humidity and time-elevated increased, fungal diversity was significantly reduced for both alpha (Q < 0.05) and beta (R2 = 0.307, P = 0.001) diversity metrics. Bacteria were unable to be modeled using the time-of-wetness framework. However, bacterial communities did change based on constant relative humidity incubations for both beta (R2 = 0.22, P = 0.001) and alpha diversity decreasing with increasing moisture starting at 85% relative humidity (Q < 0.05).ConclusionOur results demonstrate that moisture conditions can be used to develop and predict changes in fungal growth and composition onboard human-occupied spacecraft. This predictive model can be expanded upon to include other spacecraft environmental factors such as microgravity, elevated carbon dioxide conditions, and radiation exposure. Understanding microbial growth in spacecraft can help better protect astronaut health, fortify spacecraft integrity, and promote planetary protection as human activity increases in low-Earth orbit, the moon, Mars, and beyond.5L5VMn4841emXVRzhjbC6HVideo

Influence of thinning on carbon storage mediated by soil physicochemical properties and microbial community composition in large Chinese fir timber plantation

BackgroundThinning practices are useful measures in forest management and play an essential role in maintaining ecological stability. However, the effects of thinning on the soil properties and microbial community in large Chinese fir timber plantations remain unknown. The purpose of this study was to investigate the changes in soil physicochemical properties and microbial community composition in topsoil (0–20 cm) under six different intensities (i.e., 300 (R300), 450 (R450), 600 (R600), 750 (R750) and 900 (R900) trees per hectare and 1650 (R1650) as a control) in a large Chinese fir timber plantation.ResultsCompared with the CK treatment, thinning significantly altered the contents of soil organic carbon (SOC) and its fractions but not in a linear fashion; these indicators were highest in R900. In addition, thinning did not significantly affect the soil microbial community diversity indices but significantly affected the relative abundance of the core microbial community. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant bacterial phyla; the relative abundances of Proteobacteria and Acidobacteria were highest in R900, and that of Actinobacteria was lowest in R900. The dominant fungal phyla were Ascomycota, Basidiomycota and Mucoromycota; the relative abundance of Ascomycota was lowest in R900, and that of Mucoromycota was highest in R900. The fungal microbial community composition was more sensitive than the bacterial community composition. The activity of the carbon-cycling genes was not linearly correlated with thinning, and the abundance of C-cycle genes was highest in R900.ConclusionsThese findings are important because they show that SOC and its fractions and the abundance of the soil microorganism community in large Chinese fir timber plantations can be significantly altered by thinning, thus affecting the capacity for carbon storage. These results may advance our understanding of how the density of large timber plantations could be modified to promote soil carbon storage.

Modifications in the Composition of the Gut Microbiota in Rats Induced by Chronic Sleep Deprivation: Potential Relation to Mental Disorders.

Sleep deprivation(SD) has numerous negative effects on mental health. A growing body of research has confirmed the implication of gut microbiota in mental disorders. However, the specific modifications in mammalian gut microbiota following SD exhibit variations across different studies. Male specific-pathogen-free Wistar rats were given a modified multiple-platform exposure for 7 days of SD. Fecal samples were obtained from the control and SD groups both at baseline and after 7 days of SD. We utilized 16S rDNA gene sequencing to investigate the gut microbial composition and functional pathways in rats. Analysis of the microbiota composition revealed a significant change in gut microbial composition after chronic SD, especially at the phylum level. The relative abundances of p_Firmicutes, g_Romboutsia, and g_Enterococcus increased, whereas those of p_Bacteroidetes, p_Verrucomicrobia, p_Fusobacteria, g_Akkermansia, and g_Cetobacterium decreased in animals after chronic SD compared with controls or animals before SD. The ratio of Firmicutes to Bacteroidetes exhibited an increase following SD. The relative abundance of gut microbiota related to the functional pathways of GABAergic and glutamatergic synapses was observed to be diminished in rats following SD compared to pre-SD. Collectively, these findings suggest that chronic SD causes significant alterations in both the structural composition and functional pathways of the gut microbiome. Further researches are necessary to investigate the chronological and causal connections among SD, the gut microbiota and mental disorders.

Managing tobacco black shank disease using biochar: direct toxicity and indirect ecological mechanisms.

Black shank disease in tobacco, caused by Phytophthora nicotianae, can lead to yield losses of 30%-50% upon outbreak. Recently, biochar derived from agricultural waste has shown significant potential in controlling soil-borne diseases, though its mechanisms remain unclear. Over a 3-year observation period, we found that the incidence of black shank was significantly lower in plots amended with biochar compared with normal cultivation plots. To investigate the underlying mechanisms, we studied both the direct and indirect effects of biochar on black shank. Direct antifungal assays indicated that biochar reduced the total number of sporangia by 53.91%. Further pot experiments revealed a 62.34% reduction in the P. nicotianae population in the soil following biochar application. Additionally, biochar application led to notable changes in soil physicochemical properties and microbial community composition. Microbial species analysis showed that biochar promoted the aggregation of beneficial microbes such as Sphingomonas, Flavisolibacter, and Mucoromycota. Functional predictions using the PICRUSt 2 software revealed that biochar enhances bacterial functions related to antimicrobial substance synthesis (Tetracycline biosynthesis), detoxification metabolism (D-arginine and D-ornithine metabolism, arginine and proline metabolism), and lipid and fatty acid metabolism (Lipopolysaccharide biosynthesis, fatty acid biosynthesis), while fungal functions showed no significant changes. This suggests that rhizosphere bacteria play a more prominent role in the suppression of black shank by biochar, a finding supported by partial least squares path modeling analysis. Therefore, we hypothesize that biochar not only directly inhibits P. nicotianae growth but also regulates the composition of the rhizosphere microbial community, inducing the production of antimicrobial substances by rhizosphere bacteria, effectively preventing P. nicotianae invasion.IMPORTANCEBlack shank, a global soil-borne fungal disease in tobacco, currently lacks effective control methods. Notably, biochar derived from agricultural waste has shown significant potential in controlling soil-borne diseases. Over a 3-year observation period, we found that plots amended with biochar had a significantly lower incidence of black shank compared with normal cultivation plots. However, the mechanisms of disease suppression remained unclear. Through in vitro antifungal assays and pot experiments, we discovered that tobacco-derived biochar can directly inhibit the growth of the pathogen. Additionally, biochar regulates the composition of the rhizosphere microbial community, inducing rhizosphere bacteria to produce antimicrobial substances, effectively preventing pathogen invasion. This discovery reveals both the direct and indirect mechanisms by which biochar suppresses black shank in tobacco. It provides a scientific basis for developing green control technologies for black shank and offers theoretical support for the application of biochar in managing soil-borne diseases in tobacco cultivation areas.

Modeling "Two-Hit" Severe Pneumonia in Mice: Pathological Characteristics and Mechanistic Studies.

Severe pneumonia is one of the most common critical diseases in clinical practice. Existing models for severe pneumonia have limitations, leading to limited clinical translation. In this study, a two-hit severe pneumonia mouse model was established by inducing primary pneumonia through intratracheal instillation of 800μg lipopolysaccharide (LPS), followed by intraperitoneal injection of 10mg/kg LPS. The effectiveness of various inflammatory indicators and the lung tissue damage during the time course of this model were confirmed and evaluated. At 3h post two-hit, the IL-6, TNF-α levels in peripheral blood and bronchoalveolar lavage fluid (BALF), and the white blood cells, neutrophils, and lymphocytes in BALF notably exhibited the most pronounced elevation. At 12h post two-hit, the white blood cells and neutrophils in peripheral blood significantly increased, accompanied by notable alterations in splenic immune cells and worsened pulmonary histopathological damage. Transcriptomics of lung tissue, microbiota analysis of lung and gut, as well as plasma metabolomics analyses further indicated changes in transcriptional profiles, microbial composition, and metabolites due to the two-hit modeling. These results validate that the two-hit model mimics the clinical presentation of severe pneumonia and serves as a robust experimental tool for studying the pathogenesis of severe pneumonia and developing and assessing treatment strategies.

Simple tape-stripping method for highly reliable and quantitative analysis of skin microbiome.

The composition of human skin microbiome profoundly impacts host skin health and disease. However, the relationship between skin homeostasis or the development of skin diseases and daily changes in skin microbial composition is poorly understood. Longitudinal samplings at more frequent intervals would address this issue, while conventional sampling methods have technical difficulties, leading to limitations in sampling opportunities. Here, we developed a simple and stable tape-stripping method regardless of the operator's skill. Our method enables skin microbial sampling within 30 seconds and taking multiple skin microbial samples from the same body site. The amount of microbial DNA among multiple sampling sites could be measured within 13.5%. The sequencing results of multiple sampling showed high consistency, Pearson's correlation coefficient between multiple samples of 0.98. Furthermore, these results were comparable to those collected by the conventional swabbing method. These results demonstrate that our tape-stripping method enables simple microbiome collection and highly reliable quantitative skin microbiome analysis. These features of our method would lead to a further understanding of skin disease development or diagnosis of skin conditions in clinical research by increasing the opportunities for microbial sampling.

Changes in the Bile Acid Pool and Timing of Female Puberty: Potential Novel Role of Hypothalamic TGR5.

The regulation of pubertal timing and reproductive axis maturation is influenced by a myriad of physiologic and environmental inputs yet remains incompletely understood. To contrast differences in bile acid isoform profiles across defined stages of reproductive maturity in humans and a rat model of puberty and to characterize the role of bile acid signaling via hypothalamic expression of bile acid receptor populations in the rodent model. Secondary analysis and pilot studies of clinical cohorts, rodent models, ex vivo analyses of rodent hypothalamic tissues. Bile acid concentrations is the main outcome measure. Lower circulatory conjugated:deconjugated bile acid concentrations and higher total secondary bile acids were observed in postmenarcheal vs pre-/early pubertal adolescents, with similar shifts observed in infantile (postnatal day [PN]14) vs early juvenile (PN21) rats alongside increased tgr5 receptor mRNA expression within the mediobasal hypothalamus of female rats. 16S rRNA gene sequencing of the rodent gut microbiome across postnatal life revealed changes in the gut microbial composition predicted to have bile salt hydrolase activity, which was observed in parallel with the increased deconjugated and increased concentrations of secondary bile acids. We show that TGR5-stimulated GnRH release from hypothalamic explants is mediated through kisspeptin receptors and that early overexpression of human-TGR5 within the arcuate nucleus accelerates pubertal onset in female rats. Bile acid isoform shifts along stages of reproductive maturation are conserved across rodents and humans, with preclinical models providing mechanistic insight for the neuroendocrine-hepatic-gut microbiome axis as a potential moderator of pubertal timing in females.

Revealing the microbial composition changes and relationship with Fusarium caused by rot disease in the Crocus sativus L.

PurposeRot disease caused by Fusarium poses a formidable threat to the growth of saffron (Crocus sativus L.), resulting in substantial damage to both yield and quality. It is paramount to delve into the root causes of rot disease in saffron to optimize both yield and quality. Existing preventive and treatment modalities have exerted deleterious effects on corms and the natural environment. Consequently, the quest for efficacious and eco-friendly methods such as biological control agents has become an urgent imperative.MethodsThe disparate distribution of microbial communities between rhizospheric microorganisms and saffron serves as the foundational exploration for uncovering the underlying causes of rot disease. Samples from various saffron organs and rhizosphere soil were gathered, and the sequencing data from the microbial communities were interpreted using 16S rRNA and ITS gene sequencing methods. This facilitated an in-depth examination of the composition and changes of microorganisms in both healthy and diseased saffron plants.ResultsThe findings indicated rot disease reduced the abundance and diversity of microorganisms in saffron, and the fungal co-occurrence networks were less stable and their communities were more sensitive to rot disease than the bacterial community. Fusarium was the predominant genus in diseased samples, accounting for 99.19% and 89.77% of the communities in diseased leaves and corms. With corms and leaves displaying heightened susceptibility to infection compared to other plant organs. Some of the beneficial bacterial taxa enriched in the diseased plants were also identified in networks, they showed an antagonistic relationship with Fusarium, suggesting a potential for these bacteria to be used in biologically based control strategies against rot disease. These insights could prove invaluable for the development of biocontrol agents aimed at combating this plant ailment.ConclusionThese findings significantly advance our understanding of saffron-microbiome interactions and could provide fundamental and important data for improving saffron yield and quality in the process of sustainable development.

Anaerobic recovery of vivianite from waste-activated sludge through combined sludge pre-fermentation and agroforestry biomass-based biochar

The recovery of vivianite through the anaerobic digestion of waste-activated sludge has attracted considerable attention due to its operational simplicity and the high economic value of vivianite. This study concentrated on the recovery of vivianite from anaerobic fermentation systems through a strategy combining sludge pre-fermentation with the waste agricultural and forestry biomass-derived biochar (ZBC). In-depth analyses of the structure and functionality of ZBC were conducted using techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The sediment produced after the experiment and the changes in microbial community composition were characterized. The results indicated that pre-fermentation promoted phosphorus release, enhancing the synthesis of vivianite while selectively enriching respiratory and fermentative Fe (III)-reducing microorganisms. When FeOOH was used as the Fe (III) source, ZBC, through its dual action of redox functional groups and graphitization structure, increased the Fe2+ production by 243.6 % in the system dominated by respiratory Fe (III)-reducing bacteria. The optimal dosage of ZBC for the simultaneous recovery of vivianite resources and methane energy was 2.5 g/L. The combined application of pre-fermentation and ZBC provides a novel approach for the efficient recycling of vivianite and offers new insights into the reuse of agroforestry waste biomass resources.

Clustering of Gastrointestinal Microorganisms in Human Stool Samples from Ghana.

The study was conducted to identify cluster patterns of enteric microorganisms with potential etiological relevance for infectious gastroenteritis in stool samples of individuals from Ghana, which is a known high-endemicity setting for infectious gastroenteritis. These patterns were compared to previous observations with specimens from Colombian indigenous people in order to assess potentially stable clustering for temporally and spatially distinct populations from high-endemicity regions. By doing so, the study aimed to identify stable clusters as markers of microbial interaction with potential importance for etiological relevance assignment in cases of multiple enteric pathogen detections. Stool samples from 1569 Ghanaian individuals (875 from HIV patients, 30 from HIV-negative control adult patients, and 644 from children < 2 years of age) were assessed for enteric microorganisms by applying real-time PCR. As a result, nucleic acids of bacterial microorganisms were most frequently detected, followed by protozoa, microsporidia, and helminths. Interestingly, the cluster assessment confirmed interaction patterns known from the previous analysis with Colombian indigenous people, demonstrating a high likelihood of Blastocystis hominis for clustering with other microorganisms and a prominent, potentially mediating role of Dientamoeba fragilis for microbial interactions within the clusters. In conclusion, the assessment confirmed conserved clustering of enteric microorganisms with potential etiological relevance for human infectious gastroenteritis over geographically distinct high-endemicity settings. Furthermore, the composition of abundant microorganisms is more important than regional factors for the determination of the interplay of enteric microorganisms in the human gut. Thereby, some microbial pathogens and commensals seem more susceptible to a changing microbial composition in the human gut than others.

Effects of forest age and season on soil microbial communities in Chinese fir plantations.

Understanding changes in the distribution patterns and diversity of soil microbial communities from the perspectives of age-related changes, seasonal variations, and the interaction between the two factors can facilitate the management of plantations. In Chinese fir plantations, we collected soils from different depths in over-mature forests, mature forests, near-mature forests, middle-aged forests, and young forests in summer, autumn, and winter in China's subtropical regions. As the forests developed, bacterial and fungal communities' diversity changed, reached a minimum value at near-mature forests, and then increased in mature forests or over-mature forests. Near-mature forests had the lowest topological properties. The Shannon index of microbial communities varied with seasonal changes (P < 0.05). Bacterial and fungal community composition at genus level was more closely related to temperature indicators (including daily average temperature, daily maximum temperature, and daily minimum temperature) (P < 0.01, 0.5554 < R2 <0.8185) than daily average precipitation (P > 0.05, 0.0321 < R2 <0.6773). Bacteria were clustered by season and fungi were clustered by forest age. We suggested that extending the tree cultivation time of plantations could promote microbial community recovery. In addition, we found some species worthy of attention, including Bacteroidetes in autumn in over-mature forests, and Firmicutes in summer in young forests.IMPORTANCEChinese fir [Cunninghamia lanceolata (Lamb.) Hook] is an important fast-growing species with the largest artificial forest area in China, with the outstanding problems of low quality in soil. Soil microorganisms play a crucial role in soil fertility by decomposing organic matter, optimizing soil structure, and releasing essential nutrients for plant growth. In order to maintain healthy soil quality and prevent nutrient depletion and land degradation, it is crucial to understand the changes of soil microbial composition and diversity. Our study determined to reveal the change of soil microbial community from stand age, season, and the interaction between the two aspects, which is helpful to understand how interannual changes in different years and seasonal changes in one year affect soil fertility restoration and sustainable forest plantation management. It is a meaningful exploration of soil microbial communities and provides new information for further research.

The quality of beef-soybean paste and the relationship between microbial composition and flavor changes during fermentation

The quality of beef-soybean paste and the relationship between microbial composition and flavor changes during fermentation

Microbial communities mediate the effect of cover cropping on soil ecosystem functions under precipitation reduction in an agroecosystem

Cover cropping is a sustainable agricultural practice that profoundly influences soil microbial communities and ecosystem functions. However, the responses of soil ecosystem functions and microbial communities to cover cropping under the projected changes in precipitation, remain largely unexplored. To address this gap, a field experiment with cover cropping (control, hairy vetch, ryegrass, and hairy vetch plus ryegrass) and precipitation reduction (ambient precipitation and 50 % reduction in ambient precipitation) treatments was conducted from 2018 to 2020 in an agroecosystem located in the Guanzhong Plain of China. Soil ecosystem functions related to nutrient storage, nutrient cycling, and organic matter decomposition were measured to assess the soil multifunctionality index and bacterial and fungal communities were determined by Illumina NovaSeq sequencing. The results indicated that cover cropping enhanced soil multifunctionality index, and reduced precipitation strengthened this effect. Microbial community composition, rather than microbial diversity, was significantly altered by cover cropping regardless of precipitation reduction. Cover cropping increased the microbial network complexity and stability, but this effect was dampened by reduced precipitation. The microbial community composition and network complexity significantly and positively correlated with soil multifunctionality index under ambient and reduced precipitation conditions. Linear regression analyses and structural equation models collectively demonstrated that the increase in soil multifunctionality index was attributed to cover cropping-induced changes in microbial community composition and network complexity, irrespective of precipitation reduction. This study highlights the crucial role of microbial communities in driving the response of soil multifunctionality to cover cropping in the context of reduced precipitation, which has important implications for agricultural management and sustainability under future climate change scenarios.

Thinning alters nitrogen transformation processes in subtropical forest soil: Key roles of physicochemical properties

Thinning—a widely used forest management practice—can significantly influence soil nitrogen (N) cycling processes in subtropical forests. However, the effects of different thinning intensities on nitrification, denitrification, and their relationships with soil properties and microbial communities remain poorly understood. Here, we conducted a study in a subtropical forest in China and applied three thinning treatments, i.e., no thinning (0 %), intermediate thinning (10–15 %), and heavy thinning (20–25 %), and investigated the effects of thinning intensity on the potential nitrification rate (PNR), potential denitrification rate (PDR), and microbial communities. Moreover, we explored the relationships among soil physicochemical properties, microbial community structure, and nitrogen transformation rates under different thinning intensities. Our results showed that intermediate and heavy thinning significantly increased the PNR by 87 % and 61 % and decreased the PDR by 31 % and 50 % compared to that of the control, respectively. Although the bacterial community structure was markedly influenced by thinning, the fungal community structure remained stable. Importantly, changes in microbial community composition and diversity had minimal impacts on the nitrogen transformation processes, whereas soil physicochemical properties, such as pH, organic carbon content, and nitrogen forms, were identified as the primary drivers. These findings highlight the critical role of managing soil physicochemical properties to regulate nitrogen transformations in forest soils. Effective forest management should focus on precisely adjusting the thinning intensity to enhance the soil physicochemical conditions, thereby promoting more efficient nitrogen cycling and improving forest ecosystem health in subtropical regions.

Relating microbial community composition to treatment performance in an ozone-biologically active carbon filtration potable reuse treatment train

Treatment trains that couple ozone (O3) with biologically active carbon (BAC) filtration are of interest as a lower cost, more sustainable, membrane-free approach to water reuse. However, little is known about the microbial communities that are the fundamental drivers of O3-BAC treatment. The objective of this study was to demonstrate microbial community profiling as a diagnostic tool for assessing the functionality, biological stability, and resilience of coupled physical, chemical, advanced oxidative and biological processes employed in water reuse treatment. We utilized 16S rRNA gene amplicon sequencing to profile the bacterial microbiota over time throughout a potable reuse train employing coagulation, flocculation, sedimentation, ozonation, BAC filtration, granular activated carbon (GAC) adsorption, and UV disinfection. A distinct baseline microbiota was associated with each stage of treatment (ANOSIM, p < 0.05, r-stat = 0.52), each undergoing succession with time and operational shifts. Ozonation resulted in the sharpest shifts (i.e., 83.3 % average change in Genus level relative abundances, when adjusted O3:TOC ratio > 1), and also variance, in microbial community composition. Adjustment in O3:TOC ratios, temperature, filter-aid polymer, monochloramine quenching agent, and empty-bed contact time also resulted in measurable changes in the baseline microbial community composition of individual processes, but to a lesser degree. Of these, supplementation of nitrogen and phosphorus resulted in the strongest bifurcation, especially in the microbial communities inhabiting the BAC (ANOSIM: p < 0.05, BAC5 r-stat = 0.32; BAC10 r-stat = 0.54) and GAC (ANOSIM: p < 0.05, GAC10 r-stat = 0.54; GAC20 r-stat = 0.63) units. Additionally, we found that the BAC microbial community was responsive to an inoculation of microbially active media, which resulted in improved TOC removal. The findings of this study improve understanding of bacterial dynamics occurring in advanced water treatment trains and can inform improved system design and operation.

Cadmium exposure induces changes in gut microbial composition and metabolic function in long-tailed dwarf hamsters, Cricetulus longicaudatus.

Numerous studies have demonstrated that exposure to cadmium disrupts the diversity and composition of the gut microbiota, resulting in damage to organ tissue. However, there remains a lack of comprehensive understanding regarding the broader ecological reality associated with this phenomenon. In this study, we conducted a thorough evaluation of the effects of different concentrations of Cd (6, 12, 24, and 48 mg/L) over a period of 35 consecutive days on the organ viscera and the gut microbiota of long-tailed dwarf hamsters, Cricetulus longicaudatus (Rodentia: Cricetidae), using histopathological analysis, 16S rDNA, and metagenome sequencing. Our findings revealed that the results suggest that Cd exposure induced liver, spleen, and kidney damage, potentially leading to increased intestinal permeability and inflammation. These alterations were accompanied by significant perturbations in the gut microbiota composition, particularly affecting potentially pathogenic bacteria such as Prevotella and Treponema within the gut ecosystem. Consequently, host susceptibility to underlying diseases was heightened due to these changes. Notably though, Cd exposure did not significantly impact the overall structure of the gut microbiota itself. Additionally, Cd exposure induced significant changes in the metabolic functions, with the pathways related to disease and environmental information processing notably enhanced, possibly indicating stronger innate defense mechanisms against external injuries among wild mammals exposed to Cd. This study offers a novel approach to comprehensively evaluate the significant impact of Cd pollution on ecosystems by investigating both structural and functional alterations in the digestive system, as well as disruptions in intestinal flora among wild mammals.

Evaluation of activated sludge settling characteristics from microscopy images with deep convolutional neural networks and transfer learning

Timely assessment and prediction of changes in microbial compositions leading to activated sludge settling problems, such as filamentous bulking (FB), can reduce water resource recovery facilities (WRRFs) upsets, operational challenges, and negative environmental impacts. This study presents a computer vision approach to assess activated sludge-settling characteristics based on Microscopy Images (MIs). We utilize MIs to train deep convolutional neural networks (CNN) using transfer learning to investigate the morphological properties of flocs and filaments. The methodology was tested on the offline MI dataset collected over two years at a full-scale industrial WRRF in Belgium. Various CNN architectures were tested, including Inception v3, ResNet18, ResNet152, ConvNeXt-nano, and ConvNeXt-S. The sludge volume index (SVI) was used as the final prediction variable, but the method can be easily adjusted to predict any other settling metric of choice. The best-performing CNN, ConvNeXt-nano, could predict SVI values with MAE (37.51 ± 4.02), MTD (11.65 ± 1.94), MAPE (0.18 ± 0.02), and R2 (0.75 ± 0.05). The model was tested in real-life FB events, where it identified early indicators of bulking by predictive surges in SVI values. We used an explainable AI technique, Eigen-CAM, to discover key morphological indicators of sludge bulking transitions. The findings highlight the SVI multimodality issue, where SVI readings as a unidimensional metric could not capture delicate shifts from good to poor sludge settling, while the model detected these subtle changes. The key morphological attributes of threshold conditions leading to FB were identified, which can provide actionable insight for preemptive WRRF management.