Relative Abundance Of Proteobacteria Research Articles

Biochar with KMnO4-hematite modification promoted foxtail millet growth by alleviating soil Cd and Zn biotoxicity

The excessive accumulation of Cd and Zn in soil poisons crops and threatens food safety. In this study, KMnO4-hematite modified biochar (MnFeB) was developed and applied to remediate weakly alkaline Cd-Zn contaminated soil, and the heavy metal immobilization effect, plant growth, and metal ion uptake of foxtail millet were studied. MnFeB application reduced the phytotoxicity of soil heavy metals; bioavailable acid-soluble Cd and Zn were reduced by 57.79% and 35.64%, respectively, whereas stable, non-bioavailable, residual Cd and Zn increased by 96.44% and 32.08%, respectively. The chlorophyll and total protein contents and the superoxide dismutase (SOD)activity were enhanced, whereas proline, malondialdehyde, the H2O2 content, glutathione reductase (GR), ascorbate peroxidase (APX) and catalase (CAT) activities were reduced. Accordingly, the expressions of GR, APX, and CAT were downregulated, whereas the expression of MnSOD was upregulated. In addition, MnFeB promoted the net photosynthetic rate and growth of foxtail millet plants. Furthermore, MnFeB reduced the levels of Cd and Zn in the stems, leaves, and grains, decreased the bioconcentration factor of Cd and Zn in shoots, and weakened the translocation of Cd and Zn from roots to shoots. Precipitation, complexation, oxidation-reduction, ion exchange, and π-π stacking interaction were the main Cd and Zn immobilization mechanisms, and MnFeB reduced the soil bacterial community diversity and the relative abundance of Proteobacteria and Planctomycetota. This study provides a feasible and effective remediation material for Cd- and Zn-contaminated soils.

Fe(III)-mediated changes in microalgae-associated bacterial communities and dissolved organic matter characteristics: A case study for Chlorococcum sp. GD

Trivalent iron ions (Fe(III)) have important effects on aquatic ecosystems, especially on the functional diversity and stability of microorganisms and ecosystems. Here, a cultivable microalgae (Chlorococcum sp. GD) from the natural environment (Shanxi, China) were isolated and identified. A combined high-throughput 16S rRNA gene amplicon sequencing/excitation-emission matrix coupled with parallel factor (EEM-PARAFAC) analysis was used to integrated the results of Fe(III) influence on Chlorococcum sp. GD bacterial community and dissolved organic matter (DOM) characteristics through laboratory experiments. Due to the addition of Fe(III) in the form of ferric nitrate (Fe(NO3)3·9H2O), complexed with EDTA to maintain solubility and bioavailability, the bacterial community was altered. This led to a decrease in the relative abundance of Proteobacteria and Actinobacteria and an increase in the relative abundance of Cyanobacteria, especially under excessive Fe(III) treatment. In addition, the relative contribution of bacterial community dispersal limitation and homogenizing dispersal was 100 %, which may lead to differences in their local adaptation and ecological processes with homogenization of bacterial diversity and loss of function. Excessive Fe(III) caused a significant increase in the abundance of genes involved in the carbon cycle (p < 0.01) and a significant decrease in genes involved in the nitrogen cycle (p < 0.01), further affecting the overall regulatory network of gene expression. This led to an increase in the abundance of genes involved in metabolism, cellular processes, environmental information processing, genetic information processing, and human diseases. The moderate amount of Fe(III) promoted the production of microbial components and accelerated the degree of DOM humification. It is also worth mentioning that excessive Fe(III) inhibited DOM degradation. Overall, this work explored the characteristics of bacterial community and DOM changes in Fe(III)-stressed Chlorococcum sp. GD as an example, which contributes to an in-depth understanding of microbial community diversity and element cycling in aquatic ecosystems.

Nutritional and functional roles of β-mannanase on intestinal health and growth of newly weaned pigs fed two different types of feeds.

This study aimed to investigate the nutritional and functional roles of β-mannanase on the intestinal health and growth of newly weaned pigs fed a typical or low-cost formulated feeds. Twenty-four newly weaned pigs at 6.2kg ± 0.4 body weight (BW) were allotted to three dietary treatments based on a randomized complete block design with sex and initial body weight as blocks. Three dietary treatments are as follows: Control, typical nursery feeds including animal protein supplements and enzyme-treated soybean meal; LCF, low-cost formulated feeds with increased amounts of soybean meal, decreased amounts of animal protein supplements, and no enzyme-treated soybean meal; LCF+, low-cost formulated feed with β-mannanase at 100g/t, providing 800 thermostable β-mannanase unit (TMU) per kg of feed. Pigs were fed based on a three-phase feeding program for a total of 37 d. On d 37 of feeding, all pigs were euthanized and the gastrointestinal tract was removed for sample collection to analyze intestinal health parameters, mucosa-associated microbiota, and gene expression of tight junction proteins. Pigs fed LCF increased (P < 0.05) the relative abundance of Proteobacteria and Helicobacter in the jejunal mucosa, tended to decrease (P = 0.097; P = 0.098) the concentration of malondialdehyde (MDA) and the expression of zona occluden 1 (ZO-1) gene in the jejunum, tended to decrease average daily gain (ADG; P = 0.084) and final BW (P = 0.090), and decreased (P < 0.05) average daily feed intake (ADFI). Pigs fed LCF+ tended to decrease (P = 0.088) digesta viscosity, decreased (P < 0.05) the relative abundance of Helicobacter, and increased (P < 0.05) Lactobacillus in the jejunal mucosa compared to LCF. Additionally, LCF+ tended to increase final BW (P = 0.059) and ADG (P = 0.054), increased (P < 0.05) gain to feed ratio (G:F), and reduced (P < 0.05) fecal score compared to LCF. Low-cost formulated feeds with decreased amounts of animal protein supplements and increased amounts of soybean meal had negative effects on the composition of the mucosa-associated microbiota, intestinal integrity, and growth performance of nursery pigs. Beta-mannanase supplementation to low-cost formulated feeds decreased digesta viscosity, increased the relative abundance of potentially health-benefitting microbiota such as Lactobacillus, and improved growth and fecal score, thus reflecting its efficacy in low cost formulated feeds with increased amounts of soybean meal.

Effect of high oxalic acid intake on growth performance and digestion, blood parameters, rumen fermentation and microbial community in sheep

Oxalic acid, a crucial secondary metabolite prevalent in most plants, often constitutes an unavoidable component of the diet for grazing animals, particularly in saline-alkaline grasslands. This research focused on examining the effects of elevated oxalic acid consumption on various aspects of sheep health and metabolism, including growth performance, nutrient digestibility, blood biochemical indices, rumen fermentation, and microbial populations. Employing a single-factor experimental model, 24 six-month-old German Merino sheep (with an average body weight of 32.08 ± 3.43 kg) were systematically segregated into three distinct groups. Each group contained eight replicates, with each replicate comprising a single sheep. The diet of the experimental groups was enhanced with oxalic acid concentrations of 1 % (T1) and 2 % (T2), whereas the control group received no oxalic acid addition. Under ad libitum feeding, the duration of the experimental phase spanned a total of 60 days. Outcomes demonstrated that a 2 % oxalic acid augmentation notably diminished the sheep's daily weight gain (ADG) (P<0.05), elevated the feed conversion ratio (FCR) (P<0.05), and reduced the ruminal pH levels (P<0.05), compared to both control group and 1 % oxalic acid group. This pH reduction markedly curtailed the synthesis of essential ruminal constituents such as acetic acid, propionic acid, and butyric acid (P<0.05). Furthermore, there was a notable decline in serum alkaline phosphatase (ALP) levels, alongside rises in both blood urea nitrogen (BUN) and serum creatinine (CREA)(P<0.05), coupled with a significant reduction in serum calcium concentrations (P<0.05) in 2 % oxalic acid group, compared to both control group and 1 % oxalic acid group. Moreover, the 2 % oxalic acid addition adversely impacted the digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF), as well as the concentration of NH3-N in the rumen fluid (P<0.05), compared to both control group and 1 % oxalic acid group. Pertaining to rumen microorganisms, there was a significant escalation in the relative abundance of Proteobacteria at the phylum level, contrasted by a substantial reduction in the presence of Fibrobacteres (P<0.05). At the genus level, an increased concentration of oxalic acid in the diet correlated with a pronounced decline in the relative abundance of Prevotella_1, and a substantial decrease was observed in the relative abundance of Ruminococcaceae_UCG-014 (P<0.05). In summary, while sheep can acclimate to an inclusion of 1 % oxalic acid in their diet, an augmentation of 2 % oxalic acid appears detrimental, impinging upon growth performance, fiber and crude protein (CP) digestibility, blood calcium levels, rumen pH, volatile acid content, and the microbial ecosystem within the sheep’s rumen.

Spatial Variation of Oomycetes and Bacteria on Surfaces, Solutions, and Plants from a Commercial Hydroponic Greenhouse

The spatial distribution and diversity of plant pathogens and other microbial communities in commercial operations is the first step in identifying critical control points where crops may be at risk of disease. Our objective was to characterize the spatial variation of oomycete pathogens and bacteria across the production system of a greenhouse producing lettuce in hydroponics. We utilized DNA metabarcoding to identify oomycetes and 16S rRNA gene sequencing of bacteria from different production stages and sample types (surfaces, solutions, and roots) collected from a commercial greenhouse producing lettuce in deepwater culture. Pythium was the genus with the highest relative abundance (41 to 100%) across all production stages. P. dissotocum was detected in most samples, except for sowing and seedling surfaces and municipal water, where P. myriotylum was the most abundant species. Oomycete communities showed distinct clustering by production stages and sample types, where sowing and seedling surfaces and municipal water were separated from the rest. Proteobacteria had the highest relative abundance in the surfaces at the sowing (98%) and seedling (85%) stages. Municipal water was the only sample with less than 20% relative abundance of Proteobacteria and dominated by Cyanobacteria. Negative correlations between Pythium and 13 bacteria genera point to potential antagonists in hydroponics that should be further studied. Mapping the spatial variation of oomycetes and bacterial communities in a commercial greenhouse indicates that production stage and sample type influence microbial composition and potentially the risk to disease.

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.

Integrated Rice–Fish Culture Alters the Bacterioplankton Community and Its Assembly Processes

The rice–fish co-culture is an important model of carp farming in China; however, research on the dynamics and assembly of water bacterial communities in this system remains limited. Therefore, this study aimed to explore the dynamics and assembly of bacterial communities, as well as their correlation with environmental factors in paddy water. For these purposes, this study was divided into two groups: a rice–carp co-culture (WRC) group and a rice monoculture (WRM) group, with 20 rice fields in each group. After 60 days of farming, the concentrations of NH4+-N, NO2−-N, TN, and PO43− were significantly higher in the WRC group than those in the WRM group. Alpha diversity analysis showed that the Shannon index in the WRC group was significantly decreased compared with the WRM group. At the phylum level, the relative abundance of Actinobacteria significantly increased, while the relative abundance of Proteobacteria and Bacteroidetes significantly decreased in the paddy water of the WRC group. The neutral community model (NCM) indicated that a random process played a dominant role in the construction of bacterial communities in the two groups, and common carp cultivation increased migration rates, thereby affecting community assembly. The co-occurrence network displayed that common carp cultivation led to looser interactions between bacterial communities. In addition, the contents of nutrients significantly affected the abundance of bacteria in paddy water. In summary, carp cultivation decreased the diversity of bacteria and changed the relative abundance of dominant bacteria, thereby affecting the stability and assembly of bacterial communities.

Pollution characteristics of heavy metals, antibiotic and antibiotic resistance genes in the crested ibis and their habitat across different lifestyle and geography

Antibacterial resistance in wild animals has been increasingly reported worldwide, even though they are usually not directly exposed to clinically relevant antibiotics. Crested ibis, one of the rarest birds in the world, usually forages in paddy fields and prefer to nest and breed near villages that is greatly influenced by anthropogenic activities. We sampled the feces of crested ibises, as well as their habitat environment samples, to explore the pollution characteristics of heavy metals, antibiotics and antibiotic resistance genes (ARGs). Results showed that the pollution characteristics of heavy metals, antibiotic, ARGs and gut microbiota of crested ibis were more related by host lifestyle and habitats. Captive ibises had higher relative abundances of the total ARGs and tetracycline concentrations compared with feralization and wild ibises, while the heavy metal contents had shown the opposite result. The Characteristics of pollutants in the corresponding environmental samples also exhibited high similarity with the results of fecal samples. The relative abundances of Proteobacteria and Actinobacteria were significantly different between captive and wild individuals, while the abundance of majority bacterial genera was generally higher in wild populations. The concentrations of heavy metals in soil (Cd, Cu and Zn) and water (Cd, Cu, Zn and Cr) were both exceeded the background soil levels or surface water quality standards, suggesting multi-element contamination in the habitat. Ecological risk assessments of soils by Igeo and Er showed that the habitats of wild ibises were heavily and moderately contaminated by Cd, which would possibly pose a threat to the health of ibises. PLS-PM analysis indicated that microbial compositions and residual antibiotics had the most substantial impact on the dynamic changes in ARGs of ibis. Overall, this work provides a comprehensive understanding of the characteristics, risks of those contaminations, and their effects on the ARGs in the habitat of crested ibis.

Spatiotemporal distribution of environmental microbiota around animal farms adjacent to produce fields in central coast California

This study aimed to identify different environmental microbiota in animal farms adjacent to produce fields and to understand their potential flow pattern. Soil and water samples were collected from 16 locations during the winter, spring, summer, and fall seasons. In addition, a high-resolution digital elevation model helped to create a stream network to understand the potential flow of the microbiome. Metagenomic analysis of the 16 S rRNA gene revealed that soil and water samples from the four seasons harbor diverse microbiome profiles. The phylogenetic relationship of operational taxonomic units (OTUs) is separated by a maximum of 0.6 Bray-Curtis distance. Similarly, the Principal Component Analysis (P = 0.001) demonstrated the soil and water microbiome clustering across different locations and seasons. The relative abundance of Proteobacteria, Bacteroidetes, and Firmicutes was higher in the water samples than in the soil samples. In contrast, the relative abundance of Actinobacteria and Chloroflexi was higher in the soil compared to the water samples. Soil samples in summer and water samples in spring had the highest abundance of Bacteroidetes and Firmicutes, respectively. A unique microbial community structure was found in water samples, with an increased abundance of Hydrogenophaga and Solirubrobacter. Genera that were significantly abundant at a 1% false discovery rate (FDR) among seasons and soil or water samples, include Nocardioides, Gemmatimonas, JG30-KF-CM45, Massilia, Gaiellales, Sphingomonas, KD4-96, Bacillus, Streptomyces, Gaiella, and Gemmatimonadaceae. The relative abundance of pathogenic genera, including Mycobacterium, Bacteroides, Nocardia, Clostridium, and Corynebacterium, were significantly (at 1% FDR) affected by seasons and environmental type. The elevation-based stream network model suggests the potential flow of microbiomes from the animal farm to the produce fields.

Effects of nitrogen application on ammonium assimilation and microenvironment in the rhizosphere of drip-irrigated sunflower under plastic mulch.

This study investigated the effect of nitrogen application on the rhizosphere soil microenvironment of sunflower and clarified the relationship between ammonium assimilation and the microenvironment. In a field experiment high (HN, 190 kg/hm2), medium (MN, 120 kg/hm2) and low nitrogen (CK, 50 kg/hm2) treatments were made to replicate plots of sunflowers using drip irrigation. Metagenomic sequencing was used to analyze the community structure and functional genes involved in the ammonium assimilation pathway in rhizosphere soil. The findings indicated that glnA and gltB played a crucial role in the ammonium assimilation pathway in sunflower rhizosphere soil, with Actinobacteria and Proteobacteria being the primary contributors. Compared with CK treatment, the relative abundance of Actinobacteria increased by 15.57% under MN treatment, while the relative abundance decreased at flowering and maturation stages. Conversely, the relative abundance of Proteobacteria was 28.57 and 61.26% higher in the MN treatment during anthesis and maturation period, respectively, compared with the CK. Furthermore, during the bud stage and anthesis, the abundance of Actinobacteria, Proteobacteria, and their dominant species were influenced mainly by rhizosphere soil EC, ammonium nitrogen (-N), and nitrate nitrogen (-N), whereas, at maturity, soil pH and -N played a more significant role in shaping the community of ammonium-assimilating microorganisms. The MN treatment increased the root length density, surface area density, and root volume density of sunflower at the bud, flowering, and maturity stages compared to the CK. Moreover, root exudates such as oxalate and malate were positively correlated with the dominant species of Actinobacteria and Proteobacteria during anthesis and the maturation period. Under drip irrigation, applying 120 kg/hm2 of nitrogen to sunflowers effectively promoted the community structure of ammonium-assimilating microorganisms in rhizosphere soil and had a positive influence on the rhizosphere soil microenvironment and sunflower root growth.

Combined Aerobic Fermentation of Maricultural and Agricultural Solid Waste: Physicochemical Property and Bacterial Community Structure

The large-scale production of maricultural solid waste is not used effectively and has a significant impact on the environment. However, there is no report on the utilization of solid waste in mariculture of maricultural and agricultural solid waste. At present, aerobic composting is a simple and feasible means of waste resource utilization, but it also seriously pollutes the environment. This paper studied the change of physical and chemical properties (T1: solid waste + straw, T2: solid waste + cow dung + straw, T3: solid waste + cow dung + straw + 5% biochar, T4: solid waste + chicken dung + cow dung + straw + 5% biochar) and microbial succession in the composting process (T4: solid waste + chicken dung + cow dung + straw + 5% biochar) and the effect of decomposed products on seed growth. The results showed that the mixed compost of various materials had a good regulating effect on the physical and chemical indexes, and the highest temperature could reach 69.4 °C. Biochar could extend the high temperature period by 1–2 days. The germination indexes of seeds treated with T1–T4 were 75%, 80%, 81%, and 94%, respectively. Through the change of the seed germination index, it could be seen that the bacterial community structure changed significantly during composting. The Chao 1 index and Shannon index showed that the bacterial abundance and diversity index increased and then decreased. The analysis of the bacterial community structure showed that Proteobacteria and Acinetobacter were the main bacteria in composting, and the relative abundance of Proteobacteria was 81.9% at the phyla level. Acinetobacter and Pseudoxanthomonas were the main bacteria in the process of composting. Acinetobacter was the dominant bacteria in the heating stage, with an abundance of 67.2%.

Effects of 17β-Estradiol Pollution on Microbial Communities and Methane Emissions in Aerobic Water Bodies.

17β-Estradiol (E2) is a widely present trace pollutant in aquatic environments. However, its impact on microbial communities in aerobic lake waters, which are crucial for methane (CH4) production, remains unclear. This study conducted an E2 contamination experiment by constructing laboratory-simulated aerobic microecosystems. Using 16S rRNA high-throughput sequencing, the effects of E2 on bacterial and archaeal communities were systematically examined. Combined with gas chromatography, the patterns and mechanisms of E2's impact on CH4 emissions in aerobic aquatic systems were uncovered for the first time. Generally, E2 contamination increased the randomness of bacterial and archaeal community assemblies and weakened microbial interactions. Furthermore, changes occurred in the composition and ecological functions of bacterial and archaeal communities under E2 pollution. Specifically, two days after exposure to E2, the relative abundance of Proteobacteria in the low-concentration (L) and high-concentration (H) groups decreased by 6.99% and 4.01%, respectively, compared to the control group (C). Conversely, the relative abundance of Planctomycetota was 1.81% and 1.60% higher in the L and H groups, respectively. E2 contamination led to an increase in the relative abundance of the methanogenesis functional group and a decrease in that of the methanotrophy functional group. These changes led to an increase in CH4 emissions. This study comprehensively investigated the ecotoxicological effects of E2 pollution on microbial communities in aerobic water bodies and filled the knowledge gap regarding aerobic methane production under E2 contamination.

Comparing root-associated microbial communities in Tamarix ramosissima across three Xinjiang basins, China

Analyzing the root-associated microbial communities in desert plants during different seasons may provide a valuable understanding of how desert plants adapt to climate change in harsh environments. Hence, we selected root-associated microbial communities (bacteria and fungi) of Tamarix ramosissima from three regions (Cele, CL; Turpan, TLF; Mosuowan, MSW), focusing on three compartments: root endosphere (RE), rhizosphere soil (RS), and bulk soil (BS). Results indicated that the relative abundance of Actinobacteriota, Proteobacteria, and Ascomycota of root bacteria and fungi taxa was higher the in three compartments (RE, RS, and BS). In the CL region, there was a decline in the relative abundance of Proteobacteria within the RE followed by RS and BS during the autumn. During both summer and autumn, the relative abundance of Ascomycota declined with increasing sampling distance (from the TLF to the MSW to the CL) in the BS. Furthermore, in spring, the bacterial (BS) and fungal (BS) Chao1 and ACE index decreased in TLF compared to the MSW region. However, MSW had a higher bacterial Chao1 and Shannon index of the RE (in summer) and RS (in autumn) than the CL area. Overall, in spring, summer, and autumn, root-associated bacterial and fungal communities across various regions (CL, TLF, and MSW) were more responsive to climate and soil factors than plant nutrients. This research provides compelling theoretical evidence advocating for the restoration of degraded vegetation within arid environments, underscoring the critical significance of judicious plant management practices in these regions.

Intensive Citrus Cultivation Suppresses Soil Phosphorus Cycling Microbial Activity

Soil microbes are key drivers in regulating the phosphorus cycle. Elucidating the microbial mineralization process of soil phosphorus-solubilizing bacteria is of great significance for improving nutrient uptake and yield of crops. This study investigated the mechanism by which citrus cultivation affects the soil microbial acquisition strategy for phosphorus by measuring the abundance of the phoD gene, microbial community diversity and structure, and soil phosphorus fractions in the soils of citrus orchards and adjacent natural forests. The results showed that citrus cultivation could lead to a decrease in soil pH and an accumulation of available phosphorus in the soil, with a content as high as 112 mg·kg-1, which was significantly higher than that of natural forests (3.7 mg·kg-1). Citrus cultivation also affected the soil phosphorus fractions, with citrus soil having higher levels of soluble phosphorus (CaCl2-P), citrate-extractable phosphorus (Citrate-P), and mineral-bound phosphorus (HCl-P). The phosphorus fractions of natural forest soils were significantly lower than those of citrus soils, whereas the phoD gene abundance and alkaline phosphatase activity were significantly higher in natural forest soils than in citrus soils. High-throughput sequencing results showed that the Shannon diversity index of phosphate-solubilizing bacteria in citrus soils was 4.61, which was significantly lower than that of natural forests (5.35). The microbial community structure in natural forests was also different from that of citrus soils. In addition, the microbial community composition of phosphate-solubilizing bacteria in citrus soils was also different from that of natural forests, with the relative abundance of Proteobacteria being lower in natural forest soils than in citrus soils. Therefore, citrus cultivation led to a shift of soil microbial acquisition strategy for phosphorus, with external phosphorus addition being the main strategy in citrus soils, whereas microbial mineralization of organic phosphorus was the main strategy in natural forest soils to meet their growth requirements.

Effect of Polyethylene Microplastics on the Microbial Community of Saline Soils

Mulching to conserve moisture has become an important agronomic practice in saline soil cultivation, and the effects of the dual stress of salinity and microplastics on soil microbes are receiving increasing attention. In order to investigate the effect of polyethylene microplastics on the microbial community of salinized soils, this study investigated the effects of different types (chloride and sulphate) and concentrations (weak, medium, and strong) of polyethylene (PE) microplastics (1% and 4% of the dry weight mass of the soil sample) on the soil microbial community by simulating microplastic contamination in salinized soil environments indoors. The results showed that:PE microplastics reduced the diversity and abundance of microbial communities in salinized soils and were more strongly affected by sulphate saline soil treatments. The relative abundance of each group of bacteria was more strongly changed in the sulphate saline soil treatment than in the chloride saline soil treatment. At the phylum level, the relative abundance of Proteobacteria was positively correlated with the abundance of fugitive PE microplastics, whereas the relative abundances of Bacteroidota, Actinobacteriota, and Acidobacteria were negatively correlated with the abundance of fugitive PE microplastics. At the family level, the relative abundances of Flavobacteriaceae, Alcanivoracaceae, Halomonadaceae, and Sphingomonasceae increased with increasing abundance of PE microplastics. The KEGG metabolic pathway prediction showed that the relative abundance of microbial metabolism and genetic information functions were reduced by the presence of PE microplastics, and the inhibition of metabolic functions was stronger in sulphate saline soils than in chloride saline soils, whereas the inhibition of genetic information functions was weaker than that in chloride saline soils. The secondary metabolic pathways of amino acid metabolism, carbohydrate metabolism, and energy metabolism were inhibited. It was hypothesized that the reduction in metabolic functions may have been caused by the reduced relative abundance of the above-mentioned secondary metabolic pathways. This study may provide a theoretical basis for the study of the effects of microplastics and salinization on the soil environment under the dual pollution conditions.

Characterization of Microplastic Surface Bacterial Community Structure and Prediction of Ecological Risk in Poyang Lake, China

In recent years, the environmental pollution of microplastics in Poyang Lake has received increasing attention. Baisha Lake of Poyang Lake was selected as the study area, and samples of water and sediments of Baisha Lake and the microplastics therein were collected, and the polymer types of microplastics were identified as polyethylene (PE), polyester (PET), polypropylene (PP), and polystyrene (PS) using Fourier infrared spectroscopy. We also analyzed the structural composition of bacterial communities in water, in sediments, and on microplastic surfaces using 16S high-throughput sequencing. The species richness and diversity of bacteria on the microplastic surfaces were lower than those in the surrounding water and sediments. The results of NMDS analysis showed that the bacterial community structures on the microplastic surfaces differed greatly from those in the surrounding sediments and water. The bacterial community composition in water and sediment differed from that on the microplastic surfaces, and the dominant bacterial phyla on the microplastic surfaces were Proteobacteria and Bacteroidota, and their relative abundance on the microplastic surfaces was higher than that in sediment. The relative abundance of Proteobacteria was higher than that in water. The relative abundances of Bacteroidota and Actinobacteriota were significantly lower than that of water. Massilia and Pseudomonas were the dominant genera on the microplastic surfaces, and their relative abundances were significantly higher than those in the surrounding water and sediments. BugBase phenotype prediction revealed that the relative abundance of contains mobile elements, biofilm formation, potential pathogenicity, and stress tolerance phenotypes of microplastic bacterial communities were significantly higher than those of the surrounding water and sediments. The results revealed that microplastics may have contributed to the spread of harmful bacteria, including pathogenic bacteria, and increased the potential pathogenicity of bacterial communities. Additionally, microplastic surface bacterial communities had higher phenotypes of mobile gene element content. Revealing the potential harm of microplastic pollution to wetland ecology at the micro level may provide a scientific reference for maintaining the ecological stability of wetlands.

Effects of luteolin supplementation on growth, histology, antioxidant capacity, non−specific immunity and intestinal microbiota of the red swamp crayfish (Procambarus clarkii)

To investigate the effects of luteolin (LUT) on the growth, antioxidant capacity, non−specific immunity and intestinal microbiota of red swamp crayfish (Procambarus clarkii), 300 individual crayfish (4.17 ± 0.50 g average body weight and 50.19 ± 1.40 mm average body length) were randomly divided into five groups and fed with LUT doses of 0 mg/kg (CG), 50 mg/kg (LG50), 100 mg/kg (LG100), 300 mg/kg (LG300), and 500 mg/kg (LG500) for 8 weeks, respectively. Firstly, the results demonstrated that the survival and growth performance were significantly improved in all LUT added groups compared to the control (CG group), with no significant differences in hepatosomatic index, feed coefficient and muscle components, and the crayfish in LG100 group showed the maximal survival rate (SR) and specific growth rate (SGR) (P < 0.05). Secondly, histological observations displayed that the hepatopancreas and intestine tissues were not impacted in the LUT−supplemented groups, and the length of intestinal folds was significantly increased in LG100 and LG300 groups. Thirdly, LG50, LG100, and LG300 groups produced significantly increased hepatopancreatic antioxidant enzyme activities and hemolymph immune indicators compared with the control. In all experimental groups, malondialdehyde (MDA) contents were significantly reduced, as were aspartate aminotransferase and alanine aminotransferase activities. Lastly, dietary LUT specifically improved the structure and optimized the function of the gut microbiota. Compared to the control, the LG100 group displayed a significant increase in the index of Chao1 and Observed species, an increase in the relative abundance of Proteobacteria and Actinobacteria, a decrease in the ratio of Bacteroidetes to Firmicutes, and an increase in the abundance of Thermomonas, Turicibacter, Bdellovibrio and Enterococcus. PICRUSt analysis demonstrated a significant improvement in the KEGG pathway associated with isoflavone biosynthesis in the LG group. In conclusion, the present study confirms that dietary supplementation with 50−300 mg/kg LUT favors growth, non−specific immunity and antioxidant function in P. clarkii, with optimal additions ranging from 102−165 mg/kg. Furthermore, it optimized gut microbiota function, suggesting that LUT can be used as a potential feed additive for P. clarkii. These findings provide new insights for crayfish’s healthy culture.

Altered microbiome of serum exosomes in patients with acute and chronic cholecystitis.

This study aimed to investigate the differences in the microbiota composition of serum exosomes from patients with acute and chronic cholecystitis. Exosomes were isolated from the serum of cholecystitis patients through centrifugation and identified and characterized using transmission electron microscopy and nano-flow cytometry. Microbiota analysis was performed using 16S rRNA sequencing. Compared to patients with chronic cholecystitis, those with acute cholecystitis exhibited lower richness and diversity. Beta diversity analysis revealed significant differences in the microbiota composition between patients with acute and chronic cholecystitis. The relative abundance of Proteobacteria was significantly higher in exosomes from patients with acute cholecystitis, whereas Actinobacteria, Bacteroidetes, and Firmicutes were significantly more abundant in exosomes from patients with chronic cholecystitis. Furthermore, functional predictions of microbial communities using Tax4Fun analysis revealed significant differences in metabolic pathways such as amino acid metabolism, carbohydrate metabolism, and membrane transport between the two patient groups. This study confirmed the differences in the microbiota composition within serum exosomes of patients with acute and chronic cholecystitis. Serum exosomes could serve as diagnostic indicators for distinguishing acute and chronic cholecystitis.

Effects of bile acids supplementation in feed on digestive capacity, antioxidant capacity, lipid metabolism, and intestinal microorganisms in Yellow River carp (Cyprinus carpio)

This study investigated the effects of adding bile acids (BA) to the feed on several biological aspects of Yellow River carp (Cyprinus carpio). The experimental design covered four groups, namely, CT, BA1, BA2, and BA3, fed diets containing 0 mL/kg, 0.1 mL/kg, 1.0 mL/kg, and 10.0 mL/kg of BA, respectively, and the Yellow River carp with an initial body weight of 46.13±0.74 g were fed for 28 days. The results revealed that BA increased trypsin and lipase activities, positively influencing growth performance. Additionally, it enhanced the activity of intestinal antioxidant-related enzymes and the expression of related genes. Meanwhile, our findings suggested that the addition of BA might restrict hepatic lipid deposition by inhibiting lipogenesis-related genes and stimulating lipolysis-related genes. Furthermore, BA significantly altered the intestinal microorganisms' flora structure, leading to a decrease in the relative abundance of Proteobacteria.

Exploring of gut microbiota features in dyslipidemia and chronic coronary syndrome patients undergoing coronary angiography.

Chronic coronary syndrome (CCS) has a high mortality rate, and dyslipidemia is a major risk factor. Atherosclerosis, a cause of CCS, is influenced by gut microbiota dysbiosis and its metabolites. The objective of this study was to study the diversity and composition of gut microbiota and related clinical parameters among CCS patients undergoing coronary angiography and dyslipidemia patients in comparison to healthy volunteers in Thailand. CCS patients had more risk factors and higher inflammatory markers, high-sensitivity C-reactive protein (hs-CRP) than others. The alpha diversity was lower in dyslipidemia and CCS patients than in the healthy group. A significant difference in the composition of gut microbiota was observed among the three groups. The relative abundance of Proteobacteria, Fusobacteria, Enterobacteriaceae, Prevotella, and Streptococcus was significantly increased while Roseburia, Ruminococcus, and Faecalibacterium were lower in CCS patients. In CCS patients, Lachnospiraceae, Peptostreptococcaceae, and Pediococcus were positively correlated with hs-CRP. In dyslipidemia patients, Megasphaera was strongly positively correlated with triglyceride (TG) level and negatively correlated with high-density lipoprotein cholesterol (HDL-C). The modification of gut microbiota was associated with changes in clinical parameters involved in the development of coronary artery disease (CAD) in CCS patients.