Effects of Steviol Glycosides on Growth Performance, Ruminal Fermentation and Microbial Diversity of Hu Sheep.

The experiment was conducted to investigate the potential effects of steviol glycosides on growth performance, rumen fermentation processes, and microbial diversity in Hu sheep. A single-factor design was used for the trial. Twenty healthy weaned Hu lambs, possessing comparable body weights averaging 18.31 ± 1.24 kg, were randomly allocated into two distinct groups: the control group (CON) and the experimental group (STE), with each comprising 10 lambs. The CON was fed the basal diet, and the STE was supplemented with 0.07% steviol glycosides based on the basal diet. During the experimental period, variations in body weight and feed intake were closely monitored and recorded. After feeding for 90 d, blood was collected to determine blood biochemical indices, and rumen fluid samples were gathered for an in-depth analysis of rumen fermentation parameters and microbial diversity. The outcomes revealed no statistically significant differences in growth performance or serum biochemical indices between the two groups (p > 0.05). Rumen pH in STE and CON was within the normal range. The rumen ammonia nitrogen (NH3-N) and acetic acid (AA) content of STE decreased significantly compared with CON (p < 0.05). No significant variations were observed in the levels of other volatile fatty acids (VFAs) between the two groups (p > 0.05). The rumen microbial OTUs count, as well as the Shannon, Simpson, Chao1, and Ace indices, were notably lower in the STE group compared to the CON group (p < 0.05). Additionally, at the phylum level, the relative abundance of Firmicutes, Bacteroidetes, and Proteobacteria collectively accounted for over 97% of the total phylum composition. In comparison to the CON group, the STE group exhibited an increase in the relative abundance of Proteobacteria (p < 0.05), accompanied by a significant reduction in the relative abundance of Patescibacteria and Desulfobacteria (p < 0.05). At the genus level, there was a notable increase in the relative abundance of Prevotella_7 and Succinivibrionaceae_UCG_001 in the STE group, whereas the relative abundance of Rikenellaceae_RC9_gut_group significantly decreased (p < 0.05). According to the correlation analysis between rumen microflora and VFAs, the relative abundance of Succinivibrionaceae_UCG_001 displayed a significant negative correlation with AA (p < 0.05), whereas Lactobacillus exhibited a notable positive correlation with isobutyric acid (IBA) (p < 0.05). In summary, steviol glycosides had no significant effect on the production performance and blood biochemical indexes of Hu sheep. Steviol glycosides can improve rumen fermentation parameters and rumen microflora structure of Hu sheep and have a certain effect on rumen microbial diversity and composition.

Deciphering Indigenous Bacterial Diversity of Co-Polluted Sites to Unravel Its Bioremediation Potential: A Metagenomic Approach.

Polluted drains across the globe are affected due to reckless disposal of untreated industrial effluents resulting in significant water pollution affecting microbial community structure/dynamics. To elucidate this, polluted samples were collected from Budha Nala (BN) drain, Tung Dhab (TD) drain, and wastewater treatment plant (WWTP) receiving an inflow of organic pollutants as well as heavy metals due to anthropogenic activities. The sample of unpolluted pristine soil (PS) was used as control, as there is no history of usage of organic chemicals at this site. The bacterial diversity of these samples was sequenced using the Illumina MiSeq platform by amplifying the V3/V4 region of 16S rRNA. The majority of operational taxonomic unit (OTUs) at polluted sites belonged to phyla Proteobacteria specifically Gammaproteobacteria class, followed by Actinobacteria, Bacteriodetes, Chloroflexi, Firmicutes, Planctomycetes, WS6, and TM7, whereas unpolluted site revealed the prevalence of Proteobacteria followed by Actinobacteria, Planctomycetes, Firmicutes, Acidobacteria, Chloroflexi, Bacteroidetes, Verrucomicrobia, and Nitrospirae. The data sets decode unclassified species of the phyla Proteobacteria, Bacteriodetes, Chloroflexi, Firmicutes, and WS6, along with some unclassified bacterial species. The study provided a comparative study of changed microbial community structure, their possible functions across diverse geographical locations, and identifying specific bacterial genera as pollution bio-indicators of aged polluted drains.

Metagenomic Analysis of Rhizospheric Bacterial Community of Citrus Trees Expressing Phloem-Directed Antimicrobials.

Huanglongbing, also known as citrus greening, is currently the most devastating citrus disease with limited success in prevention and mitigation. A promising strategy for Huanglongbing control is the use of antimicrobials fused to a carrier protein (phloem protein of 16 kDa or PP16) that targets vascular tissues. This study investigated the effects of genetically modified citrus trees expressing Citrus sinensis PP16 (CsPP16) fused to human lysozyme and ß-defensin-2 on the soil microbiome diversity using 16S amplicon analysis. The results indicated that there were no significant alterations in alpha diversity, beta diversity, phylogenetic diversity, differential abundance, or functional prediction between the antimicrobial phloem-overexpressing plants and the control group, suggesting minimal impact on microbial community structure. However, microbiota diversity analysis revealed distinct bacterial assemblages between the rhizosphere soil and root environments. This study helps to understand the ecological implications of crops expressing phloem-targeted antimicrobials for vascular disease management, with minimal impact on soil microbiota.

Integrative analysis of microbiome and metabolome revealed the effect of microbial inoculant on microbial community diversity and function in rhizospheric soil under tobacco monoculture.

Over-application of chemical fertilizers and continuous cropping obstacles seriously restrict the sustainable development of tobacco production. Localized fertilization of beneficial microbes has potential advantages in achieving higher productivity, but the underlying biological mechanisms of interactions between rhizospheric microorganisms and the related metabolic cycle remain poorly characterized. Here, an integrative analysis of microbiomes with non-targeted metabolomics was performed on 30 soil samples of rhizosphere, root surrounding, and bulk soils from flue-cured tobacco under continuous and non-continuous monocropping systems. The analysis was conducted using UPLC-MS/MS platforms and high-throughput amplicon sequencing targeting the bacterial 16S rRNA gene and fungal ITS gene. The microbial inoculant consisted of Bacillus subtilis, B. velezensis, and B. licheniformis at the ratio of 1:1:1 in effective microbial counts, improved the cured leaf yield and disease resistance of tobacco, and enhanced nicotine and nitrogen contents of tobacco leaves. The bacterial taxa Rhizobium, Pseudomonas, Sphingomonadaceae, and Burkholderiaceae of the phylum Proteobacteria accumulated in high relative abundance and were identified as biomarkers following the application of the microbial inoculant. Under continuous monocropping, metabolomics demonstrated that the application of the microbial inoculant significantly affected the soil metabolite spectrum, and the differential metabolites were significantly enriched to the synthesis and degradation of nicotine (nicotinate and nicotinamide metabolism and biosynthesis of alkaloids derived from nicotinic acid). In addition, microbes were closely related to the accumulation of metabolites through correlation analysis. The interactions between plant roots and rhizospheric microorganisms provide valuable information for understanding how these beneficial microbes affect complex biological processes and the adaption capacity of plants to environments.IMPORTANCEThis study elaborated on how the microbial fertilizer significantly changed overall community structures and metabolite spectrum of rhizospheric microbes, which provide insights into the process of rhizosphere microbial remolding in response to continuous monocropping. we verified the hypothesis that the application of the microbial inoculant in continuous cropping would lead to the selection of distinct microbiota communities by establishing models to correlate biomarkers. Through correlation analysis of the microbiome and metabolome, we proved that rhizospheric microbes were closely related to the accumulation of metabolites, including the synthesis and degradation of nicotine. The interactions between plant roots and rhizospheric microorganisms provide valuable information for understanding how these beneficial microbes affect complex biological processes and the adaption capacity of plants to environments.

Comparing microbial populations from diverse hydrothermal features in Yellowstone National Park: hot springs and mud volcanoes.

Geothermal features, such as hot springs and mud volcanoes, host diverse microbial life, including many extremophile organisms. The physicochemical parameters of the geothermal feature, such as temperature, pH, and heavy metal concentration, can influence the alpha and beta diversity of microbial life in these environments, as can spatiotemporal differences between sites and sampling. In this study, water and sediment samples were collected and analyzed from eight geothermal sites at Yellowstone National Park, including six hot springs, a mud volcano, and an acidic lake within the same week in July 2019, and these geothermal sites varied greatly in their temperature, pH, and chemical composition. All samples were processed and analyzed with the same methodology and taxonomic profiles and alpha and beta diversity metrics determined with 16S rRNA sequencing. These microbial diversity results were then analyzed with respect to pH, temperature, and chemical composition of the geothermal features. Results indicated that predominant microbial species varied greatly depending on the physicochemical composition of the geothermal site, with decreases in pH and increases in dissolved heavy metals in the water corresponding to decreases in alpha diversity, especially in the sediment samples. Similarly, sites with acidic pH values had more similar microbial populations (beta diversity) to one another than to relatively neutral or alkaline pH geothermal sites. This study suggests that pH and/or heavy metal concentration is a more important driver for microbial diversity and population profile than the temperature for these sites and is also the first reported microbial diversity study for multiple geothermal sites in Yellowstone National Park, including the relatively new mud volcano Black Dragon's Caldron, which erupted in 1948.

Exploration of gut microbial diversity of pheasants through pyrosequencing of 16S rRNA gene.

Despite the diversity of microbiota in birds is similar to that of other animals, there is a lack of research on the gut microbial diversity of nondomesticated bird species. This study aims to address this gap in knowledge by analyzing the bacterial communities present in the gut of two important game bird species, the Ring-necked pheasant (Phasianus colchicus) and the Green pheasant (Phasianus versicolor) to understand the gut microbial diversity of these species. The gut microbiome of 10 individual pheasants from two different species was studied using pooled fecal samples. We used 16S rRNA gene sequencing on the Ion S5 XL System next-generation sequencing with Mothur and SILVA Database for taxonomic division. An average of 141 different operational taxonomic units were detected in the gut microbiome. Analysis of microbial classification revealed the presence of 191 genera belonging to 12 different phyla in both pheasants. Alpha diversity indices revealed that P. colchicus exhibited most prevalence firmicutes with bacillus species microbial community than P. versicolor. Alpha diversity indices indicated that P. colchicus had a more diverse community and P. versicolor had a greater diversity of evolutionary lineages, while both species had similar levels of species richness and sample inclusiveness. These findings may have implications for the health and well-being of pheasants, serving as a reference for their bacterial diversity. Additionally, they provide a baseline for future research and conservation efforts aimed at improving the health and well-being of these and possibly other avian species.

Exploring the biotechnological potential of novel soil-derived Klebsiella sp. and Chryseobacterium sp. strains using phytate as sole carbon source.

Phosphorus (P) is essential for biological systems, playing a pivotal role in energy metabolism and forming crucial structural components of DNA and RNA. Yet its bioavailable forms are scarce. Phytate, a major form of stored phosphorus in cereals and soils, is poorly bioavailable due to its complex structure. Phytases, enzymes that hydrolyze phytate to release useable phosphorus, are vital in overcoming this limitation and have significant biotechnological applications. This study employed novel method to isolate and characterize bacterial strains capable of metabolizing phytate as the sole carbon and phosphorus source from the Andes mountains soils. Ten strains from the genera Klebsiella and Chryseobacterium were isolated, with Chryseobacterium sp. CP-77 and Klebsiella pneumoniae CP-84 showing specific activities of 3.5 ± 0.4 nkat/mg and 40.8 ± 5 nkat/mg, respectively. Genomic sequencing revealed significant genetic diversity, suggesting CP-77 may represent a novel Chryseobacterium species. A fosmid library screening identified several phytase genes, including a 3-phytase in CP-77 and a glucose 1-phosphatase and 3-phytase in CP-84. Phylogenetic analysis confirmed the novelty of these enzymes. These findings highlight the potential of phytase-producing bacteria in sustainable agriculture by enhancing phosphorus bioavailability, reducing reliance on synthetic fertilizers, and contributing to environmental management. This study expands our biotechnological toolkit for microbial phosphorus management and underscores the importance of exploring poorly characterized environments for novel microbial functions. The integration of direct cultivation with metagenomic screening offers robust approaches for discovering microbial biocatalysts, promoting sustainable agricultural practices, and advancing environmental conservation.

Effects of Short-Term Tillage on Rhizosphere Soil Nitrogen Mineralization and Microbial Community Composition in the Double-Cropping Rice Field.

Soil extracellular enzyme plays a vital role in changing soil nitrogen (N) mineralization of rice field. However, the effects of soil extracellular enzyme activities (EEA) and microbial community composition response to N mineralization of rice field under short-term tillage treatment needed to be further explored. In this study, we investigated the impact of short-term (8-year) tillage practices on rhizosphere soil N transformation rate, soil enzyme activities, soil microorganism community structure and their N mineralization function genes in double-cropping rice field in southern China. The experiment consisted of four tillage treatments: rotary tillage with crop straw input (RT), conventional tillage with crop straw input (CT), no-tillage with crop straw retention (NT), and rotary tillage with all crop straws removed as a control (RTO). The results indicated that rhizosphere soil N transformation rate in paddy field in NT and RTO treatments were significantly lower than that in RT and CT treatments. Compared with NT and RTO treatments, soil protease, urease, ß-glucosaminidase and arginase activities with CT treatment were significantly improved, as were abundances of soil sub, npr and chiA with CT and RT treatments. Moreover, diversity of overall soil bacterial communities in NT and RTO treatments were significantly lower than that in RT and CT treatments. Soil chitinolytic and bacterial ureolytic communities were also obviously changed combined with tillage and crop straw input practices.

A comparative study of sampling methods in the detection of esophageal cancer-related microbiota.

Esophageal cancer (EC) is a multifaceted disease. Our understanding of the involvement of esophageal microbiota in its pathogenesis and progression is limited, which is due to the lack of proper endoscopic sampling methods. Hereby, we conducted a comparative analysis of paired samples obtained through endoscopic brushing and cytosponge, aiming at assessing the feasibility of using cytosponge as a minimally invasive sampling way for studying esophageal microbiota. Our findings suggest that cytosponge sampling yielded significantly superior community richness and diversity compared to endoscopic brushing in both controls (non-cancerous) and EC individuals. The analysis of beta-diversity revealed distinct microbial community pattern in the genus diversity between the two sampling methods, underscoring the importance of selecting appropriate sampling methods to effectively characterize the esophageal microbiota. Specifically, Lactococcus and Serratia showed higher abundance in the samples collected by endoscopic brushing, while Alloprevotella and Leptotrichia were more enriched in the samples collected by cytosponge. These differences in dominant microbes were associated with metabolic pathways that particularly were related to host inflammation, such as pyruvate and glucose metabolisms. Notably, the phylogenetic levels of the microbiota indicated varied explanatory power for different detection purposes. This study underscores the substantial impact of sampling method selection on the acquisition of esophageal microbiota associated with the EC development, encompassing considerations of both abundance and diversity. This highlights the significance of selecting an appropriate sampling method for investigating the esophageal microbial status and studying the micro-environment in EC-related individuals. IMPORTANCE: This study addresses a critical issue in esophageal cancer study by comparing two different sampling methods, endoscopic brushing and cytosponge, for investigating the esophageal microbiota. Our work highlights the suitability of the cytosponge technique as a minimally invasive sampling method for studying the esophageal microbiota and emphasizes the importance of selecting an appropriate sampling method to characterize the microbial community. Our findings have significant implications for advancing the understanding of the role of the esophageal microbiota in cancer development and will inform future research and clinical approaches in this field.

Microbial influence in Spanish bentonite slurry microcosms: Unveiling a-year long geochemical evolution and early-stage copper corrosion related to nuclear waste repositories.

The deep geological repository (DGR) concept consists of storing radioactive waste in metal canisters, surrounded by compacted bentonite, and placed deeply into a geological formation. Here, bentonite slurry microcosms with copper canisters, inoculated with bacterial consortium and amended with acetate, lactate and sulfate were set up to investigate their geochemical evolution over a year under anoxic conditions. The impact of microbial communities on the corrosion of the copper canisters in an early-stage (45 days) was also assessed. The amended bacterial consortium and electron donors/acceptor accelerated the microbial activity, while the heat-shocked process had a retarding effect. The microbial communities partially oxidize lactate to acetate, which is subsequently consumed when the lactate is depleted. Early-stage microbial communities showed that the bacterial consortium reduced microbial diversity with Pseudomonas and Stenotrophomonas dominating the community. However, sulfate-reducing bacteria such as Desulfocurvibacter, Anaerosolibacter, and Desulfosporosinus were enriched coupling oxidation of lactate/acetate with reduction of sulfates. The generated biogenic sulfides, which could mediate the conversion of copper oxides (possibly formed by trapped oxygen molecules on the bentonite or driven by the reduction of H2O) to copper sulfide (Cu2S), were identified by X-ray photoelectron spectroscopy (XPS). Overall, these findings shed light on the ideal geochemical conditions that would affect the stability of DGR barriers, emphasizing the impact of the SRB on the corrosion of the metal canisters, the gas generation, and the interaction with components of the bentonite.

New insights into assembly processes and driving factors of urban soil microbial community under environmental stress in Beijing.

Rapid urbanization leads to drastic environmental changes, directly or indirectly affecting the structure and function of soil microbial communities. However, the ecological response of soil microbes to environmental stresses has not yet been fully explored. In this study, we used high-throughput sequencing to analyze the assembly mechanism and driving factors of soil microbial community under environmental stresses. The results indicated that environmental stresses significantly affected soil properties and the levels of beryllium, cobalt, antimony, and vanadium contamination in soil generally increased from the suburban areas toward the city core. The composition and distribution of soil microbial communities demonstrated clear differences under different levels of environmental stress, but there was no significant difference in microbial diversity. Random forest and partial least squares structural equation modeling results suggested that multiple factors influenced microbial diversity, but antimony was the key driver. The influence of environmental stress led to deterministic processes dominating microbial community assembly processes, which promoted the regional homogenization of soil microbes. Therefore, this study provides new insights into urban soil microbial management under environmental stresses.

Dysbiosis and interactions of the mycobiome and bacteriome in mucosal lesions of erosive and non-erosive oral lichen planus patients.

Background: Oral lichen planus (OLP) is a common oral mucosal disease, clinically categorized into erosive OLP (EOLP) and non-erosive OLP (NEOLP) based on symptoms, but its pathogenic mechanism remains unclear. This study aims to explore the relationship between OLP and the oral microbiome. Methods: We collected oral mucosal samples from 49 patients and 10 healthy individuals and conducted 16S rRNA and ITS gene sequencing to explore the oral fungal and bacterial communities. Results: We observed significantly lower α diversity of fungi in the EOLP group, with Candida being significantly enriched as the main dominant genus. In the NEOLP group, Aspergillaceae were significantly enriched. The EOLP group showed significant enrichment of Aggregatibacter and Lactobacillus, but the relative abundance of Streptococcus was notably lower than in the other two groups. In the NEOLP group, two species including Prevotella intermedia were significantly enriched. The microbial co-occurrence and co-exclusion networks display distinct characteristics across the three groups, with Lactobacillus assuming a significant bridging role in the ELOP group. Conclusions: Our study indicates that EOLP and NEOLP experience varying degrees of dysbiosis at both the fungal and bacterial levels. Therefore, the pathogenic mechanisms and interactive relationships of these microbiota associated with OLP merit further in-depth investigation.

The microbial community in the oral lesions of EOLP patients exhibits highly distinctive features, both in terms of bacteria and fungi.In NEOLP patients, the overall bacterial composition does not exhibit significant differences compared to the healthy population, but P. intermedia and Aspergillaceae are notably enriched.

Multi-scale analysis of acidophilic microbial consortium biofilm's tolerance of lithium and cobalt ions in bioleaching.

Metal ions stress will inhibit the oxidation capacity of iron and sulfur of an acidophilic microbial consortium (AMC), which leads to reduced bioleaching efficiency. This work explored the impacts of Li+ and Co2+ on the composition and function of AMC biofilms with a multi-scale approach. At the reactor scale, the results indicated that the oxidative activity, the adsorption capacity, and the biofilm formation ability of AMC on pyrite surfaces decreased under 500 mM Li+ and 500 mM Co2+. At the biofilm scale, the electrochemical measurements showed that Li+ and Co2+ inhibited the charge transfer between the pyrite working electrode and the biofilm, and decreased the corrosion current density of the pyrite working electrode. At the cell scale, the content of proteins in extracellular polymers substrate (EPS) increased as the concentrations of metal ions increased. Moreover, the adsorption capacity of EPS for Li+ and Co2+ increased. At the microbial consortium scale, a BugBase phenotype analysis showed that under 500 mM Li+ and 500 mM Co2+, the antioxidant stress capacity and the content of mobile gene elements in AMC increased. The results in this work can provide useful data and theoretical support for the regulation strategy of the bioleaching of spent lithium-ion batteries to recover valuable metals.

Effects of vegetation degradation on soil microbial communities and ecosystem multifunctionality in a karst region, southwest China.

Vegetation degradation caused by intense human disturbances poses a significant challenge to the preservation and improvement of ecosystem functions and services in the karst region of southwest China. Soil microorganisms are major regulators of ecosystem multifunctionality (EMF). Currently, there is a dearth of knowledge regarding the effects of vegetation degradation on soil microbial communities and their corresponding multiple ecosystem functions in karst regions. In this study, we selected the vegetation degradation sequences of second natural forest (NF), agroforestry (AS) and cropland (CL) to investigate the diversity of bacterial, fungal and protistan communities, and their hierarchical co-occurrence network, and EMF to explore the relationships between them. Compared to the NF, the carbon cycling index, nitrogen cycling index, soil water regulation power, and the EMF were significantly decreased by 8.2%-50.6%, 48.7%-86.8%, 19.8%-24.5%, and 31.4%-69.5% in the AS and CL, respectively. The development of EMF can be explained by the fungal, protistan and microbial hierarchical ß-diversity, as well as the complexity (e.g. degree) of microbial hierarchical interactions during the process of vegetation degradation. Notably, correlations between the abundances of sensitive amplicon sequence variants (sASVs) for different karst vegetation types and EMF varied in distinct network modules, being positive in module 1 and negative in module 2. Moreover, the relative abundance of keystone taxa in fungal and protistan communities provided greater contributions to EMF than the bacterial communities. Additionally, random forest modeling showed that carbon and nitrogen sources, and soil water content, and trace elements (e.g. exchangeable magnesium, iron, manganese, and zinc) were identified as key driving factors of the EMF. Collectively, our findings demonstrate that vegetation degradation obviously alters soil microbial diversities and hierarchical interactions, emphasizing their key role in maintaining ecosystem functions and health in karst regions.

Alteration of Gut Microbiota Composition and Diversity in Acute and/or Chronic Graft-versus-Host Disease Following Hematopoietic Stem Cell Transplantation: A Prospective Cohort Study.

Changes in gut microbiome composition have been implicated in the pathogenesis of graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our objective was to explore the microbial abundance in patients with GvHD after allo-HSCT. We conducted a single-center, prospective study in patients who underwent allo-HSCT and developed grade II or higher acute GvHD and/or moderate or severe chronic GvHD, to explore the microbial abundance of taxa at the phylum, family, genus, and species level, and we utilized alpha and beta diversity indices to further describe our findings. We collected fecal specimens at -2 to +2 (T1), +11 to +17 (T2), +25 to +30 (T3), +90 (T4), and +180 (T5) days to assess changes in gut microbiota, with day 0 being the day of allo-HSCT. We included 20 allo-HSCT recipients in the study. Compared with timepoint T1, at timepoint T4 we found a significant decrease in the abundance of Proteobacteria phylum (14.22% at T1 vs. 4.07% at T4, p = 0.01) and Enterobacteriaceae family (13.3% at T1 vs. <0.05% at T4, p < 0.05), as well as a significant increase in Enterococcus species (0.1% at T1 vs. 12.8% at T4, p < 0.05) in patients who developed acute GvHD. Regarding patients who developed chronic GvHD after allo-HSCT, there was a significant reduction in the abundance of Eurobactereaceae family (1.32% at T1 vs. 0.53% at T4, p < 0.05) and Roseruria genus (3.97% at T1 vs. 0.09% at T4, p < 0.05) at T4 compared with T1. Alpha and beta diversity analyses did not reveal a difference in the abundance of bacteria at the genus level in GvHD patients at T4 compared with T1. Our study reinforces results from previous studies regarding changes in gut microbiota in patients with acute GvHD and provides new data regarding the gut microbiome changes in chronic GvHD. Future studies will need to incorporate clinical parameters in their analyses to establish their association with specific changes in gut microbiota in patients with GvHD after allo-HSCT.

Microbial trace based on PCR-DGGE to evaluate the ripening stage of minas artisanal cheeses from the Canastra microregion produced by different dairies.

The Minas artisanal cheese from the Serra da Canastra (MAC-CM) microregion is a traditional product due to its production and ripening process. Artisanal chesses manufactured with raw cow's milk and endogenous dairy starters ("also known as pingo") have distinctive flavors and other sensory characteristics because of the unknown microbiota. The aim of this study was to evaluate the microbiota during 30 days of ripening, the physicochemical changes, and their relation in MACs produced in two different microregions located in the Serra da Canastra microregion through culture-dependent and culture-independent methods. The MACs were collected in the cities of Bambuí (MAC-CMB) and Tapiraí (MAC-CMT) in the Canastra microregion (n = 21). Cheeses uniqueness was demonstrated with the multivariate analysis that joined the microbiota and physicochemical characteristics, mainly to the proteolysis process, in which the MAC-CMT showed deeper proteolysis (DI -T0:14.18; T30: 13.95), while the MAC-CMB reached only a primary level (EI -T0:24.23; T30: 31.10). Abiotic factors were responsible for the differences in microbial diversity between the cheese farms. Different microbial groups: the prokaryotes, like Corynebacterium variabile, Lactococcus lactis, and Staphylococcus saprophyticus; and the eukaryotes, like Kluyveromyces lactis and Diutina catenulata dominated ripening over time. The microbial community and proteolysis were responsible for the predominance of volatile groups, with alcohols predominating in MAC-CMB and free fatty acids/acids and esters in MAC-CMT.

Changes of microbial communities and metabolites in the fermentation of persimmon vinegar by bioaugmentation fermentation.

To evaluate the effects of bioaugmentation fermentation inoculated with one ester-producing strain (Wickerhamomyces anomalus ZX-1) and two strains of lactic acid bacteria (Lactobacillus plantarum CGMCC 24035 and Lactobacillus acidophilus R2) for improving the flavor of persimmon vinegar, microbial community, flavor compounds and metabolites were analyzed. The results of microbial diversity analysis showed that bioaugmentation fermentation significantly increased the abundance of Lactobacillus, Saccharomyces, Pichia and Wickerhamomyces, while the abundance of Acetobacter, Apiotrichum, Delftia, Komagataeibacter, Kregervanrija and Aspergillus significantly decreased. After bioaugmentation fermentation, the taste was softer, and the sensory irritancy of acetic acid was significantly reduced. The analysis of HS-SPME-GC-MS and untargeted metabolomics based on LC-MS/MS showed that the contents of citric acid, lactic acid, malic acid, ethyl lactate, methyl acetate, isocitrate, acetoin and 2,3-butanediol were significantly increased. By multivariate analysis, 33 differential metabolites were screened out to construct the correlation between the differential metabolites and microorganisms. Pearson correlation analysis showed that methyl acetate, ethyl lactate, betaine, aconitic acid, acetoin, 2,3-butanediol and isocitrate positively associated with Wickerhamomyces and Lactobacillus. The results confirmed that the quality of persimmon vinegar was improved by bioaugmentation fermentation.

Effects of temperature fluctuations on the quality and microbial diversity of beef meatballs during simulated cold chain distribution.

BACKGROUND: Cold chain distribution with multiple links maintains low temperatures to ensure the quality of meat products, whereas temperature fluctuations during this are often disregarded by the industry. The present study simulated two distinct temperatures cold chain distribution processes. Quality indicators and high-throughput sequencing were employed to investigate the effects of temperature fluctuations on the quality and microbial diversity of beef meatballs during cold chain distribution. RESULTS: Quality indicators revealed that temperature fluctuations during simulated cold chain distribution significantly (P < 0.05) exacerbated the quality deterioration of beef meatballs. High-throughput sequencing demonstrated that temperature fluctuations affected the diversity and structure of microbial community. Lower microbial species abundance and higher microbial species diversity were observed in the temperature fluctuations group. Proteobacteria and Pseudomonas were identified as the dominant phylum and genus in beef meatballs, respectively, exhibiting faster growth rates and greater relative abundance under temperature fluctuations. CONCLUSION: The present study demonstrates that temperature fluctuations during simulated cold chain distribution can worsen spoilage and shorten the shelf life of beef meatballs. It also offers certain insights into the spoilage mechanism and preservation of meat products during cold chain distribution. © 2024 Society of Chemical Industry.

A review: Marine aquaculture impacts marine microbial communities.

Marine aquaculture is key for protein production but disrupts marine ecosystems by releasing excess feed and pharmaceuticals, thus affecting marine microbes. Though vital, its environmental impact often remains overlooked. This article delves into mariculture's effects on marine microbes, including bacteria, fungi, viruses, and antibiotic-resistance genes in seawater and sediments. It highlights how different mariculture practices-open, pond, and cage culture-affect these microbial communities. Mariculture's release of nutrients, antibiotics, and heavy metals alters the microbial composition, diversity, and functions. Integrated multi-trophic aquaculture, a promising sustainable approach, is still developing and needs refinement. A deep understanding of mariculture's impact on microbial ecosystems is crucial to minimize pollution and foster sustainable practices, paving the way for the industry's sustainable advancement.