Search Results (656)

While the gut microbiota of obese children in Mexico has been studied, its relationship with depressive and anxiety symptoms in obese adults remains unexplored. The aim of this study was to describe the gut microbiota profile of Mexican adults with obesity and its association with depression and anxiety. We sequenced the V3-V4 region of the 16S rRNA gene from stool samples of obese adults categorized into four groups: control (OCG), with depressive symptoms (OD), with anxiety symptoms (OAx), or with both (ODAx). Alpha diversity was assessed using t-tests, beta diversity was assessed with PERMANOVA, and taxonomic differences was assessed with LEfSe. Associations between bacterial genera and clinical variables were analyzed using the Maaslin2 library. Bacteroidota was the most prevalent phylum, and Prevotella was the dominant enterotype across all groups. Although overall diversity did not differ significantly, 30 distinct taxonomic biomarkers were identified among groups as follows: 4 in OCG (Firmicutes), 5 in OD (Firmicutes, Bacteroidota), 13 in OAx (Firmicutes, Bacteroidetes, Fusobacteroidota, Proteobacteria), and 8 in ODAx (Firmicutes). This is the first study to identify distinct gut microbiota profiles in obese Mexican adults with depressive and anxiety symptoms. These findings suggest important microbial biomarkers for improving the diagnosis and treatment of mental health conditions in obesity. Full article

The purpose of this work was to obtain specialized enrichment cultures from an original extreme acidophilic consortium of extremely acidophilic microorganisms and to study their microbial community composition and biotechnological potential. At temperatures of 25, 35, 40 and 50 °C, distinct enrichments of extremely acidophilic microorganisms used in the processes of bioleaching sulfide ores were obtained using nutrient media containing ferrous sulfate, elemental sulfur and a copper sulfide concentrate as nutrient inorganic substrates, with and without the addition of 0.02% yeast extract. The microbial community composition was studied using the sequencing of the V3–V4 hypervariable region of the 16S rRNA genes. The different growth conditions led to changes in the microbial composition and relative abundance of mesophilic and moderately thermophilic, strict autotrophic and mixotrophic microorganisms in members of the genera Acidithiobacillus, Sulfobacillus, Leptospirillum, Acidibacillus, Ferroplasma and Cuniculiplasma. The dynamics of the oxidation of ferrous iron, sulfur, and sulfide minerals (pyrite and chalcopyrite) by the enrichments was also studied in the temperature range of 25 to 50 °C. The study of enrichment cultures using the molecular biological method using the metabarcoding method of variable V3–24 V4 fragments of 16S rRNA genes showed that enrichment cultures obtained under different conditions differed in composition, which can be explained by differences in the physiological properties of the identified microorganisms. Regarding the dynamics of the oxidation of ferrous ions, sulfur, and sulfide minerals (pyrite and chalcopyrite), each enrichment culture was studied at a temperature range of 25 to 50 °C and indicated that all obtained enrichments were capable of oxidizing ferrous iron, sulfur and minerals at different rates. The obtained enrichment cultures may be used in further work to increase bioleaching by using the suitable inoculum for the temperature and process conditions. Full article

Vermicomposting is a sustainable biotechnological process that transforms organic waste through the synergistic activity of earthworms, such as Eisenia fetida, and their associated microbiota. This study evaluated bacterial and physicochemical dynamics during the vermicomposting of bovine manure by analyzing the microbial composition of the substrate and the gut of E. fetida at three time points (weeks 0, 6, and 12). The V3–V4 region of the 16S rRNA gene was sequenced, and microbial diversity was characterized using QIIME2. Significant differences in alpha diversity (observed features, Shannon index, and phylogenetic diversity) and beta diversity indicated active microbial succession. Proteobacteria, Bacteroidota, and Actinobacteriota were the dominant phyla, with abundances varying across habitats and over time. A significant enrichment of Proteobacteria, Bacteroidota, and the genera Chryseolinea, Flavobacterium, and Sphingomonas was observed in the manure treatments. In contrast, Actinobacteriota, Firmicutes, and the genera Methylobacter, Brevibacillus, Enhygromyxa, and Bacillus, among others, were distinctive of the gut samples and contributed to their dissimilarity from the manure treatments. Simultaneously, the physicochemical parameters indicated progressive substrate stabilization and nutrient enrichment. Notably, the organic matter and total organic carbon contents decreased (from 79.47% to 47.80% and from 46.10% to 27.73%, respectively), whereas the total nitrogen content increased (from 1.70% to 2.23%); these effects reduced the C/N ratio, which is a recognized indicator of maturity, from 27.13 to 12.40. The macronutrient contents also increased, with final values of 1.41% for phosphorus, 1.50% for potassium, 0.89% for magnesium, and 2.81% for calcium. These results demonstrate that vermicomposting modifies microbial communities and enhances substrate quality, supporting its use as a biofertilizer for sustainable agriculture, soil restoration, and agrochemical reduction. Full article

Soil salinization poses a significant constraint to agricultural productivity. However, certain plant growth-promoting bacteria (PGPB) can mitigate salinity stress and enhance crop performance. In this study, a bacterial isolate, R-18, isolated from saline-alkali soil in Ningxia, China, was identified as Enterobacter bugandensis based on 16S rRNA gene sequencing. The isolate was characterized for its morphological, biochemical, and plant growth-promoting traits and was evaluated for its potential to alleviate NaCl-induced stress in maize (Zea mays L.) under hydroponic conditions. Isolate R-18 exhibited halotolerance, surviving at NaCl concentrations ranging from 2.0% to 10.0%, and alkaliphilic adaptation, growing at pH 8.0–11.0. Biochemical assays confirmed it as a Gram-negative bacterium, displaying positive reactions in the Voges–Proskauer (V–P) tests, catalase activity, citrate utilization, fluorescent pigment production, starch hydrolysis, gelatin liquefaction, and ammonia production, while testing negative for the methyl red and cellulose hydrolysis. Notably, isolate R-18 demonstrated multiple plant growth-promoting attributes, including nitrogen fixation, phosphate and potassium solubilization, ACC deaminase activity, and indole-3-acetic acid (IAA) biosynthesis. Under 100 mM NaCl stress, inoculation with isolate R-18 significantly enhanced maize growth, increasing plant height, stem dry weight, root fresh weight, and root dry weight by 20.64%, 47.06%, 34.52%, and 31.25%, respectively. Furthermore, isolate R-18 improved ion homeostasis by elevating the K⁺/Na⁺ ratio in maize tissues. Physiological analyses revealed increased chlorophyll and proline content, alongside reduced malondialdehyde (MDA) levels, indicating mitigated oxidative damage. Antioxidant enzyme activity was modulated, with decreased superoxide dismutase (SOD) and peroxidase (POD) activities but increased catalase (CAT) activity. These findings demonstrated that Enterobacter bugandensis R-18 effectively alleviated NaCl-induced growth inhibition in maize by enhancing osmotic adjustment, reducing oxidative stress, and improving ion balance. Full article

Vibrio parahaemolyticus is a major foodborne pathogen worldwide, responsible for seafood-associated poisoning. Among its toxin genes, tdh2 is the most critical. To investigate the role of tdh2 in V. parahaemolyticus under gastrointestinal conditions, we constructed tdh2 deletion and complementation strains and compared their survival under acid (pH 3 and 4) and bile stress (2%). The results showed that tdh2 expression was significantly upregulated under cold (4 °C) and bile stress (0.9%). Survival assays and PI staining revealed that the tdh2 mutant strain (VP: △tdh2) was more sensitive to acid and bile stress than the wild-type (WT), and this sensitivity was rescued by tdh2 complementation. These findings suggest that tdh2 plays a protective role in enhancing V. parahaemolyticus tolerance to acid and bile stress. In the VP: △tdh2 strain, seven genes were significantly upregulated and six were downregulated as a result of tdh2 deletion. These genes included VPA1332 (vtrA), VPA1348 (vtrB), VP2467 (ompU), VP0301 and VP1995 (ABC transporters), VP0527 (nhaR), and VP2553 (rpoS), among others. Additionally, LC-MS/MS analysis identified 12 differential metabolites between the WT and VP: △tdh2 strains, including phosphatidylserine (PS) (17:2 (9Z,12Z) /0:0 and 20:1 (11Z) /0:0), phosphatidylglycerol (PG) (17:0/0:0), flavin mononucleotide (FMN), and various nucleotides. The protective mechanism of tdh2 may involve preserving cell membrane permeability through regulation of ompU and ABC transporters and enhancing electron transfer efficiency via regulation of nhaR. The resulting reduction in ATP, DNA, and RNA synthesis—along with changes in membrane permeability and electron transfer due to decreased FMN—likely contributed to the reduced survival of the VP: △tdh2 strain. Meanwhile, the cells actively synthesized phospholipids to repair membrane damage, leading to increased levels of PS and PG. This study provides important insights into strategies for preventing and controlling food poisoning caused by tdh⁺ V. parahaemolyticus. Full article

The involvement of oral bacteria in the pathogenesis of distant organs, such as the heart, lungs, brain, liver, and intestine, has been shown. We analyzed the distribution of bacterial species in the resected aortic valve by 16S rRNA metagenomic analysis and directly compared their gene sequences with those in the oral cavity. Thirty-two patients with aortic stenosis or aortic regurgitation who underwent aortic valve replacement were enrolled in this study. Antibody titer against periodontal pathogenic bacteria in the patient’s serum was analyzed. The genetic background and distribution of bacterial species on subgingival plaque, the dorsal surface of the tongue, and the resected aortic valve were analyzed. Patients with aortic valve disease were shown to have more severe periodontal disease by the detection of antibodies against Socransky’s red-complex bacteria of periodontitis. Bacterial DNA was detected in the aortic valves of 12 out of 32 patients. The genomic sequences of the V3-V4 region of the 16S rRNA in some bacteria isolated from the aortic valves of six patients who underwent metagenomic analysis were identical to those found in the oral cavity. The findings indicate that bacteria detected in the aortic valve may be introduced through oral dysbiosis, a condition characterized by an imbalance in the oral microbiota that increases the risk of periodontal disease and dental caries. Oral dysbiosis and the resulting potential bacteremia are associated with the pathogenesis of aortic valve diseases. Full article

Background/Objectives: Colitis is a chronic condition affecting millions worldwide. Purple muscadine wine polyphenols have a unique composition and possible disease-preventive properties. This study aims to determine how dealcoholized muscadine wine (DMW) affects the development of colitis and gut microbiome in IL-10^−/− mice, compared to wild types (WT). Methods: Six-week-old male IL-10^−/− and WT C57BL/6 mice were fed either a DMW-supplemented diet (4.8% v/w) or a control diet based on AIN-93M for 154 days. Colitis severity was evaluated by disease activity, intestinal permeability, gene expression of cytokines and tight junction proteins in the colon, and inflammatory cytokines in the serum. Fecal samples were collected for gut microbiome profiling via 16S rRNA gene sequencing. Results: DMW contained predominantly anthocyanins and a significant amount of ellagic acid. IL-10^−/− mice developed mild colitis as indicated by the disease activity index. DMW × gene interactions decreased intestinal permeability, colonic mRNA levels of IL-1β, and serum TNF-α in the IL-10^−/− mice. DMW suppressed the colonic mRNA levels of IL-6, enhanced the gene expression of ZO-1, but did not influence the mRNA level of TNF-α or occludin. While DMW did not alter α-diversity of the gut microbiome, it significantly influenced β-diversity in the WT mice. DMW significantly reduced the relative abundances of Akkermansia in the IL-10^−/− and WT mice. DMW and DMW×gene interaction decreased the relative abundance of Parasutterella only in IL-10^−/− mice. Conclusions: These results suggested that polyphenols from DMW interacted with genes to moderately alleviate the development of colitis in IL-10^−/− mice and could be a useful dietary strategy for IBD prevention. Full article

The long-term monocropping of red kidney beans in agricultural fields can lead to the occurrence of soil-borne diseases. Alterations in the composition of the soil microbial community are a primary cause of soil-borne diseases and a key factor in continuous cropping obstacles. Research exploring how different cultivation modes can modify the diversity and composition of the rhizosphere microbial community in red kidney beans, and thus mitigate the effects of continuous cropping obstacles, is ongoing. This study employed three cultivation modes: the continuous monocropping of red kidney beans, continuous monocropping of soybeans, and red kidney bean–soybean intercropping. To elucidate the composition and diversity of rhizosphere microbial communities, we conducted amplicon sequencing targeting the V3-V4 hypervariable regions of the bacterial 16S rRNA gene and the ITS1 region of fungal ribosomal DNA across distinct growth stages. The obtained sequencing data provide a robust basis for estimating soil microbial diversity. We observed that, under the intercropping mode, the composition of both bacteria and fungi more closely resembled that of soybean monocropping. The monocropping of red kidney beans increased the richness of rhizosphere bacteria and fungi and promoted the accumulation of pathogenic microorganisms. In contrast, intercropping cultivation and soybean monocropping favored the accumulation of beneficial bacteria such as Bacillus and Streptomyce, reduced pathogenic fungi including Alternaria and Mortierell, and exhibited less microbial variation across different growth stages. Compared to the monocropping of red kidney beans, these systems demonstrated more stable microbial structure and composition. The findings of this study will inform sustainable agricultural practices and soil management strategies. Full article

A 14-day study was conducted to evaluate the effect of litter type (dirty litter, DL; fresh litter, FL) and Salmonella Enteritidis SE challenge (no challenge, NC; challenge, SE) on the growth performance and cecal microbial composition of neonate chicks. Day-old chicks (n = 240, Ross 708 male) were allocated to a 2 × 2 factorial design consisting of four treatments: chicks raised on dirty litter (CONDL), chicks raised on fresh litter (CONFL); and chicks raised on litter types similar to CONDL and CONFL but inoculated with 7.46 × 108 CFU SE/mL at d 1 (CONDLSE and CONFLSE). The performance indices measured included body weight (BW), body weight gain (BWG), feed intake (FI), mortality, and feed conversion ratio (FCR). Cecal SE concentration was assessed on d 3 and 14, and ceca were collected from chicks on day 14 for DNA extraction. The Illumina Miseq platform was used for microbiome analysis of the V3–V4 region of the 16S rRNA gene. The interaction of litter type and SE influenced FCR and FI. CONDL recorded the poorest FCR (1.832). FI was highest and similar in CONFLSE, CONDL, and CONDLSE (0.655, 0.692, and 0.677, respectively). Cecal SE concentration was significantly reduced in CONDLSE at d 3 and 14. Alpha diversity was higher (p < 0.05) in the DL compared to that in NC. Beta diversity showed a separation (p < 0.05) between the DL and the FL. Comparative tree analysis revealed 21 differential significant genera, with 14 prevalent in the DL and 7 in the FL, specifically, bacteria genera such as Lactobacillus, Clostridia_vadinBB60_group, Lachnospira, Oscillospiraceae UCG_005, and Marvinbryantia, which play significant roles relating to improved growth performance, metabolic homeostasis within the gut, energy metabolism, and short-chain fatty acid (SCFA) utilization. Our results concluded that litter management regimen differentially alters the microbiome of chicks, which accounts for the improved performance and exclusion of pathogens in the study. Full article

Phlebotomine sandflies are the primary vectors of Leishmania parasites, the causative agents of leishmaniasis. In India, Phlebotomus argentipes is the confirmed vector of Leishmania donovani. The sandfly gut microbiota plays a crucial role in Leishmania development and transmission, yet it remains largely understudied. This study used a metagenomic approach targeting the V3–V4 region of the 16S rRNA gene to compare the gut bacterial communities of P. argentipes and Sergentomyia babu prevalent in Kerala. A total of 18 distinct bacterial phyla were identified in P. argentipes, and 14 in S. babu, both dominated by Proteobacteria, Actinobacteria, and Firmicutes. A total of 315 genera were identified in P. argentipes, with a high relative abundance of Pseudomonas (6.3%), whereas S. babu harbored 327 genera, with Pseudomonas showing a higher relative abundance of 11%. Unique to P. argentipes, bacterial phyla such as Fusobacteria, Armatimonadetes, Elusimicrobia, Chlamydiae, and Crenarchaeota were identified, whereas Chlorobi was specific to S. babu. Additionally, 145 species were identified in P. argentipes, compared to 164 species in S. babu. These findings provide a comparative baseline of gut microbial diversity between vector and non-vector sandfly species, offering a foundation for future functional investigations into vector competence. Full article

Background: Symbiotic gut microbiota can enhance cancer therapy efficacy, while treatment-induced dysbiosis may reduce effectiveness or increase toxicity. Our preclinical study compared the anticancer effects and impact on fecal microbiota and metabolites of two water-soluble SN-38 derivatives (BN-MePPR and BN-MOA), with those observed after treatment with Irinotecan, and the FOLFOX regimen in NOD scid gamma mice bearing patient-derived colon adenocarcinoma xenografts (CRC PDX). Methods: Five individual experiments with Irinotecan and its derivatives and eight individual experiments with FOLFOX were conducted using eight CRC PDX models. Chemotherapeutics were administered intraperitoneally 4–5 times at 5-day intervals. Fecal samples were collected before and after treatment. Microbiota composition was analyzed by 16S rRNA gene (V3–V4 regions) sequencing. Mass spectrometry was used to quantify short-chain fatty acids (SCFAs) and amino acids (AAs). Results: All treatments significantly inhibited tumor growth versus controls. However, no significant changes were observed in gut microbiota α- and β-diversity between treated and untreated groups. Tumor progression in controls was associated with increased abundance of Marvinbryantia, Lactobacillus, Ruminococcus, and [Eubacterium] nodatum group. FOLFOX-treated mice showed increased Marvinbryantia, Bacteroides, and Candidatus Arthromitus, and decreased Akkermansia. No distinct taxa changes were found in the Irinotecan or derivative groups. SCFA levels remained unchanged across groups, while BN-MePPR, BN-MOA, and Irinotecan all increased AA concentrations. Conclusions: Contrary to earlier toxicological data, these findings indicate a relatively limited impact of the tested chemotherapeutics on the gut microbiome and metabolome, emphasizing the importance of research method selection in preclinical studies. Full article

Of many housekeeping genes, gyrB and rpoB are used as alternative markers to 16S rDNA to analyze Rhizobia and Agrobacteria communities. However, the extent to which the targeted genes and their corresponding primers could be suitable in metagenomic studies within communities belonging to the two taxa remains elusive. This work evaluates in silico the taxonomic resolution of partial regions of two housekeeping and 16S rRNA genes in differentiating between Rhizobia and Agrobacteria. The study confirmed V5–V7 as the best 16S rDNA variable region for differentiating all the genera at a 100% threshold. However, rpoB and gyrB markers outcompeted the 16S rDNA in terms of taxonomic resolution regardless of the threshold, possibly replacing the use of 16S rDNA V-regions in metagenomics studies of Rhizobia and Agrobacteria. Full article

ES5-4^T, a Gram-positive, motile, aerobic, and rod-shaped strain, was isolated from the rhizosphere of Galinsoga parviflora growing in the selenium-rich ore area of Enshi, Hubei Province, China. This strain can grow at pH levels of 5.0–10.0 and temperatures of 4–42 °C, with optimal growth at pH 7.0 and 28 °C. It was found to resist NaCl up to 5% (w/v), with an optimal growth condition of 0.5–1.0%. The strain exhibited tolerance to selenite (Se⁴⁺) concentrations up to 5000 mg/L. The major fatty acids of the ES5-4^T strain were anteiso-C_15:0 (46.5%) and C_16:0 (21.7%), its predominant respiratory quinone was MK-7, and its polar lipids included diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and an unidentified phospholipid (PL). The presence of the 16S rRNA gene sequence implies that ES5-4^T belongs to a member of the genus Paenibacillus, with the highest sequence similarity of 98.4% to Paenibacillus pabuli NBRC 13638^T. The bac120 tree also confirmed that the strain is within the genus Paenibacillus. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between ES5-4^T and closely related members of the genus Paenibacillus were all below the cutoff levels of 95–96% and 70%, respectively. Based on a polyphasic approach, including phenotypic, chemotaxonomic, and phylogenetic analyses, the ES5-4^T strain is proposed as a novel species of the genus Paenibacillus, for which the name Paenibacillus hubeiensis sp. nov. is proposed. This type strain is designated as ES5-4^T (=GDMCC 1.3540^T = KCTC 43478^T). Full article

Citrus is one of the most widely consumed fruits in the world, and its cultivation industry continues to develop rapidly. However, the roles of soil protistan communities during citrus growth are not yet fully understood, despite the potential significance of these communities to the health and quality of citrus. In this study, we examined the soil properties and protistan communities in Eureka lemon farmlands located in Chongqing, China, during the flowering and fruiting stages of cultivation, both in greenhouse and open-field settings. In general, the majority of the measured soil properties (including nutrients and enzyme activities) exhibited higher values in open-field farmlands in comparison to those observed in greenhouse counterparts. According to the results of high-throughput sequencing based on the V9 region of eukaryotic 18S rRNA gene, the diversity of soil protistan communities was also higher in open-field farmlands, and both lemon growth stage and cultivation modes showed significant effects on soil protistan compositions. The transition from traditional agricultural practices to greenhouse farming resulted in a significant transformation of the soil protistan community. This transformation manifested as a shift towards a state characterized by diminished nutrient cycling capabilities. This decline was evidenced by an increase in phototrophs (Archaeplastida) and a concomitant decrease in consumers (Stramenopiles and Alveolata). Community assembly analysis revealed deterministic processes that controlled the succession of soil protistan communities in lemon farmlands. It has been established that environmental associations have the capacity to recognize nitrogen in soils, thereby providing a deterministic selection process for protistan community assembly. Furthermore, a production index was calculated based on 12 quality parameters of lemons, and the results indicated that lemons from greenhouse farms exhibited a lower quality compared to those from open fields. The structure equation model revealed a direct correlation between the quality of lemons and the cultivation methods employed, as well as the composition of soil protists. The present study offers insights into the mechanisms underlying the correlations between the soil protistan community and lemon quality in response to changes in the cultivation modes. Full article

Seed microbes play crucial roles in plant health, but studying their diversity is challenging due to host DNA contamination. This study aimed to optimise methodologies for investigating seed microbiomes across diverse plant species, focusing on the efficacy of peptide nucleic acid (PNA) clamps to reduce host DNA amplification. We tested PNA clamps on three plant species: Melaleuca quinquenervia (tree), Microlaena stipoides, and Themeda triandra (grasses). The effectiveness of PNA clamps was assessed through in silico analysis, axenic tissue culture, and metabarcoding techniques. In silico analysis confirmed the specificity of PNA clamps to the 16S rRNA gene V4 region of chloroplasts in the grass species. Axenic tissue culture experiments showed that applying PNA clamps at both 1 µM and 0.25 µM concentrations significantly reduced plant DNA amplification. Metabarcoding analyses further confirmed that PNA clamps effectively suppressed host DNA, enhancing microbial diversity estimates across all three species while preserving core microbial taxa. The efficacy of the clamps varied among host species, with T. triandra exhibiting the highest blocking efficacy, and chloroplast clamps outperforming mitochondrial ones. This study demonstrates that PNA clamps are a useful for improving seed endophyte metabarcoding datasets, although they require optimisation for some plant species. This knowledge will contribute to enhancing our understanding of seed microbiome diversity and its ecological implications. Full article