Proportion Of Proteobacteria Research Articles

Nano-selenium ameliorates microplastics-induced injury: Histology, antioxidant capacity, immunity and intestinal microbiota of grass carp (Ctenopharyngodon idella)

Microplastics (MPs) are pollutants widely distributed in the aquatic environments and causing various degrees of aquatic toxicity to aquatic organisms, which has attracted global attention in recent years. Nano-selenium (NSe) has been shown to have the potential to mitigate the harmful impacts of toxic substances. However, there is currently no reported evidence regarding the protective influence of NSe against the adverse effects of MPs. The aim of this study is to determine whether NSe could ameliorate the polystyrene (PS)-MPs-induced injury in grass carp (Ctenopharyngodon idella). The individuals of grass carp were assigned into three groups: (1) the control group fed with basal diet, (2) the PS group fed with basal diet and exposed to PS-MPs, and (3) the NSe group fed with diet supplemented with NSe and exposed to PS-MPs. Our results indicated that NSe administration significantly alleviated the histological damage caused by the PS-MPs in the liver and intestine with lower goblet cell count and larger villus height in the intestine, and significantly lower damage score in the liver. Moreover, NSe mitigated PS-MPs-induced oxidative stress through restoring the activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA)) except the intestinal CAT activity. Furthermore, NSe supplementation could help fish maintain lower transcriptional level of the immune-related genes (Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88)), inflammation-related genes (major histocompatibility complex class II (MHC-II) and interleukin 8 (IL-8)) and antioxidant enzyme-related genes (nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) and kelch-like ECH-associated protein 1 (Keap-1)) after PS-MPs exposure. Besides, NSe supplementation dramatically helped maintain the intestinal microbial composition, for example, the proportion of Proteobacteria in the grass carp intestine of the NSe group (41 %) was similar to that of the control group (34 %) while 85 % of the PS group. NSe also played a significant protective role in intestinal microbial diversity, effectively resisting the damage on intestinal microbial diversity due to PS-MPs exposure. PS-MPs reduced the beneficial bacteria and increased the pathogenic microorganism like Aeromonas, which was undeniable signs of intestinal dysbiosis. Functional analysis indicated that PS-MPs affected intestinal microbiota functions like inhibition of metabolism, while NSe could significantly alleviate the damage. Our findings suggested that NSe could ameliorate PS-MPs-induced injury, which could contribute to the better understanding of the ecotoxicological effects of MPs on fish and help develop relevant mitigation strategies.

Microbiomes of Primary Soils and Mining Heaps of Polymetallic Ore Quarries

This research evaluates the development of microbiomes in primary soils, forming in various mining dumps in the arid terrain in the Republic of Bashkortostan, Russia. A metagenomic analysis of the communities was performed by sequencing extended gene sequences. The evaluation of the agro-chemical properties was in accordance with conventional pedology methods. Inverse voltammetry was used to measure the heavy metals (lead, cadmium, mercury, zinc, copper, and nickel) and arsenic content. In all the samples studied, Actinobacteria and Proteobacteria phylas dominated, and, in smaller numbers, Acidobacteria and Bacteroidetes were present. In the natural samples, the proportion of Actinobacteria was higher, and the proportions of Proteobacteria and Bacteroidetes were lower than in the samples from anthropogenically disrupted soils. Verrucomicrobia bacteria and Thaumarchaeota archaea were not found in the forming soils of the Kulyurtau and Tubinsky quarries, although in all other samples, there was a significant content of representatives of these types. Soil formation was observed at the Kulyurtau and Tubinsky mines, with a self-restoration period of more than 30 years. The microbial communities of the forming soils were similar in species richness to the background soils, and the alpha diversity showed a high level of dispersion, although the beta diversity had a different clustering, but the absence of Verrucomicrobia and Thaumarchaeota phyla in the samples from both sites indicates the underdevelopment of new soils compared with the natural background. Agrochemical indicators showed a dependence on the type of growing vegetation and the degree of anthropogenic load, and the correlation with the microbial composition of soils was traced poorly.

The Characteristics of the Root-Zone Soil's Biological Properties and Microbial Community Structure in Grafted Star Anise Plantations.

Extensive management seriously affects the output, quality, and sustainable development of star anise, and grafting is commonly used to improve its production and quality. Although many studies have explored the effects of grafting on soil microorganisms for other plants, there is a lack of research on aromatic plants, especially on the soil ecosystems of star anise plantations. The effect of grafting star anise on the soil's biological characteristics and microbial composition remains unclear. The soil's enzyme activities, soil microbial biomass, and microbial community composition in grafted and non-grafted star anise plantations in Guangxi, China were studied using high-throughput sequencing technology. The results showed that the microbial biomass carbon and phosphorus contents in the soils of grafted star anise were significantly lower and the phosphatase activity was significantly higher than in the soils of non-grafted star anise. In comparison with the soils of non-grafted star anise plantations, the proportions of Proteobacteria, Acidobacteria, Actinobacteria, and WPS-2 decreased and the proportions of Chloroflexi, Planctomycetes, and Verrucomicrobia increased in the grafted star anise plantations. Meanwhile, Bacteroidetes was a dominant bacterial phylum unique to the soil of the grafted star anise plantations. Moreover, the proportions of Ascomycota and Basidiomycota increased and the proportions of Mortierellomycota and unclassified_k_Fungi decreased in the soils of the grafted star anise plantations. Furthermore, Basidiomycota and Rozellomycota had significant dominance in the grafted star anise plantations. In general, grafting can improve soil fertility and maintain soil health by promoting soil nutrient cycling and increasing the soil's microbial diversity.

Comparison of mucosal microbiomes from biliary tract among patients with extrahepatic cholangiocarcinoma, patients with chronic cholecystitis, and healthy controls.

550 Background: Cholangiocarcinoma (CCA) is a malignancy associated with a poor prognosis. Gut microbiome dysbiosis is considered to be related with multiple disease, including and cancer. However, relationship between mucosal microbiome dysbiosis and CCA remains unclear. In this study, we evaluated mucosal microbiome of patients with extrahepatic-CCA (EH-CCA) and compared it with patients with chronic cholecystitis (CC) and living liver donors who served as healthy control (HC), to understand the role of microbiome in development EH-CCA. Methods: A total of 18 patients with EH-CCA, 21 patients with CC, and 17 HC were included. During operation, swab sample were obtained from cancer tissue of patient with EH-CCA and from gallbladder in other participants, respectively. The bacterial 16S rRNA gene (V3/V4 region) was amplified using PCR and sequenced on the Illumina MiSeq platform. The QIIME 2 pipelines were used to analyze the raw data. Results: The median age were 71, 53, and 29 years for patients with EH-CCA, patients with CC, and HC, respectively. The mean number of operational taxonomic unit were significantly higher in the CCA (13,037 [SD 9,676]) compared to HC (5,045 [12,679]; p<0.001). Among the sample from HC, the most abundant taxa at phylum level was Firmicutes (74.47%), followed by Bacteroidota (14.8%), and Proteobacteria accounted for only 2%. In the CC group, Firmicutes is most abundant (63.15%) phylum, followed by Proteobacteria (22.09%). In contrast, among the samples from CCA, Proteobacteria were the most common phylum (50.43%). Pairwise comparison of α-diversity measured by Chao1 index showed that richness was higher in samples from CC compared to other groups (vs HC, p=0.02; vs CCA, p<0.001). In terms of α-diversity measured by Shannon index, samples from cancer have lower diversity compared to healthy controls ( p<0.001), however, no significant differences were found between samples from cancer and CC ( p=0.1). The Principal Coordinate Analysis plot based on Bray-Curtis distance showed that all three groups formed significantly separate clusters (p=0.001). The linear discriminant analysis effect size showed that the most abundant taxa from samples from CCA were Enterobacter, Klebsiella, and Fusobacterium. In the samples from HC, Limosilactobacillus, Lachnospiraceae_NK4A136_group, and Faecalibacterium were most significant, while Lactobacillus and Pseudomonas were most abundant among the CC group. Conclusions: This study compared the mucosal microbiome from biliary tract among patients with CCA, patients with CC, and HC. All three groups showed significantly different microbiome profiles. In CCA sample, the proportion of Proteobacteria is high, and diversity were low, suggesting mucosal microbial dysbiosis. Further studies are needed to investigate the clinical implications of microbial dysbiosis in CCA.

Aspirin eugenol ester affects ileal barrier function, inflammatory response and microbiota in broilers under lipopolysaccharide-induced immune stress conditions.

The aim of this study was to investigate the effects of aspirin eugenol ester (AEE) on ileal immune function in broilers under lipopolysaccharide (LPS)-induced immune stress. Two hundred and forty one-day-old male Arbor Acres chicks were randomly divided into four groups (saline, LPS, saline + AEE and LPS + AEE) with six replicates of ten broilers each. The saline group and LPS group were fed the normal diet, while the other two groups received normal diet plus 0.1 g/kg AEE. Broilers in the LPS and LPS + AEE groups were injected intraperitoneally with 0.5 mg/kg B.W LPS in saline for seven consecutive days beginning at 14 days of age, while broilers in the saline and saline + AEE groups were injected with saline only. The results showed that AEE improved the ileal morphology and increased the ratio of villus height to crypt depth of immune-stressed broilers. LPS-induced immune stress significantly reduced the expression of the genes for the tight junction proteins occludin, zonula occludens-1 (ZO-1), claudin-1 and claudin-2, in the ileum, while AEE significantly up-regulated the expression of these genes. Compared with the saline group, the LPS-treated chickens showed significantly increased mRNA expression of the inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), cyclooxygenase-2 (COX-2), and microsomal Prostaglandin E Synthesase-1 (mPGES-1) in the ileum, while they were significantly decreased by AEE supplementation. In addition, analysis of the ileal bacterial composition showed that compared with saline and LPS + AEE groups, the proportion of Firmicutes and Lactobacillus in the LPS group was lower, while the proportion of Proteobacteria and Escherichia-Shigella was higher. Similarly, Line Discriminant Analysis Effect Size (LEfSe) analysis showed that compared with the LPS group, Brevibacillus was dominant in the saline group, while the LPS + AEE group was rich in Rhizobium, Lachnoclostridium, Ruminococcaceae, Faecalibacterium, Negativibacillus, Oscillospiraceae, and Flavonifractor. These results indicate that dietary supplementation with 0.1 g/kg AEE could protect the intestinal health by improving the intestinal villus morphology, enhancing the expression of tight junction genes and alleviating inflammation to resist the immune stress caused by LPS stimulation in broilers, and the mechanism may involve COX-2-related signal transduction and improved intestinal microbiota composition.

Control effect of root exudates from mycorrhizal watermelon seedlings on Fusarium wilt and the bacterial community in continuously cropped soil.

Watermelon (Citrullus lanatus) is susceptible to wilt disease caused by Fusarium oxysporum f. sp niveum (FON). AMF colonization alleviates watermelon wilt and regulates the composition of root exudates, but the effects of mycorrhizal watermelon root exudates on watermelon Fusarium wilt is not well understood. Root exudates of watermelon inoculated with AMF (Funeliformis mosseae or Glomus versiformme) were collected in this study. Then the root exudates of control plants and mycorrhizal plants were used to irrigate watermelon in continuous cropping soil, respectively. Meanwhile, the watermelon growth, antioxidant enzyme activity, rhizosphere soil enzyme activities and bacterial community composition, as well as the control effect on FON were analyzed. The results indicated that mycorrhizal watermelon root exudates promoted the growth of watermelon seedlings and increased soil enzyme activities, actinomyces, and the quantity of bacteria in rhizosphere soil. The proportion of Proteobacteria and Bacteroides was decreased, and the proportion of Actinobacteria, Firmicutes, and Chloroflexi in rhizosphere soil was increased when the seedlings were watered with high concentrations of mycorrhizal root exudates. The dominant bacterial genera in rhizosphere soil were Kaistobacter, Rhodanobacter, Thermomonas, Devosia, and Bacillus. The root exudates of mycorrhizal watermelon could reduce the disease index of Fusarium wilt by 6.7-30%, and five ml/L of watermelon root exudates inoculated with F. mosseae had the strongest inhibitory effect on watermelon Fusarium wilt. Our results suggest mycorrhizal watermelon root exudates changed the composition of bacteria and soil enzyme activities in rhizosphere soil, which increase the resistance of watermelon to Fusarium wilt and promoted the growth of plants in continuous cropping soil.

Treatment of atrazine-containing wastewater by algae-bacteria consortia: Signal transmission and metabolic mechanism

Atrazine is a toxic endocrine disruptor. Biological treatment methods are considered to be effective. In the present study, a modified version of the algae-bacteria consortia (ABC) was established and a control was simultaneously set up to investigate the synergistic relationship between bacteria and algae and the mechanism by which atrazine is metabolized by those microorganisms. The total nitrogen (TN) removal efficiency of the ABC reached 89.24% and the atrazine concentration was reduced to below the level recommended by the Environment Protection Agency (EPA) regulatory standards within 25 days. The protein signal released from the extracellular polymeric substances (EPS) secreted by the microorganisms triggered the resistance mechanism of the algae, and the conversion of humic acid to fulvic acid and electron transfer constituted the synergistic mechanism between the bacteria and algae. The mechanism by which atrazine is metabolized by the ABC mainly consists of hydrogen bonding, H–pi interactions, and cation exchange with atzA for hydrolysis, followed by a reaction with atzC for decomposition to non-toxic cyanuric acid. Proteobacteria was the dominant phylum for bacterial community evolution under atrazine stress, and the analysis revealed that the removal of atrazine within the ABC was mainly dependent on the proportion of Proteobacteria and the expression of degradation genes (p < 0.01). EPS played a major role in the removal of atrazine within the single bacteria group (p < 0.01).

Inoculation with Bacillus cereus DW019 Modulates Growth, Yield and Rhizospheric Microbial Community of Cherry Tomato

Plant growth-promoting rhizobacteria (PGPR) play an important role in promoting plant growth and increasing crop yield. Bacillus cereus DW019, which was previously isolated from an ion-absorbed rare-earth ore of Ganzhou in Southeastern China, has been considered as a PGPR due to its production of indole-3-acetic acid (IAA), ammonia and siderophore, but its promoting effect on plants remains poorly understood. In this study, autoclaved dead cells and viable cells of Bacillus cereus DW019 at different concentrations were inoculated into pot-cultivated cherry tomato (Lycopersicon esculentum) to investigate the promoting effect on plant growth and yield. A total of 70 days after inoculation, the plants and fruits of cherry tomato were harvested, and their growth indicators, yields, and nutrients were measured. The results showed that biomass, stem thickness, plant height and root length were significantly promoted and that the vitamin C, soluble sugar and soluble protein were significantly increased. Inoculation with Bacillus cereus also modulated the rhizospheric microbial community diversity and structure, especially the proportions of Proteobacteria and Actinobacteriota, which in turn improved the plant height, fresh weight, nutritional quality and rhizosphere soil bacterial diversity of cherry tomato. All the findings suggest that Bacillus cereus DW019 is beneficial to the growth of crops and improves the yield of cherry tomato, suggesting that Bacillus cereus DW019 could be developed into a potential biofertilizer to be used as an agricultural inoculant to increase crop yield and improve the soil ecosystem.

Exploring antibiotic resistance load in paddy-upland rotation fields amended with commercial organic and chemical/slow release fertilizer.

Agricultural fertilization caused the dissemination of antibiotic resistance genes (ARGs) in agro-ecological environment, which poses a global threat to crop-food safety and human health. However, few studies are known about the influence of different agricultural fertilization modes on antibiotic resistome in the paddy-upland rotation soils. Therefore, we conducted a field experiment to compare the effect of different fertilization (chemical fertilizer, slow release fertilizer and commercial organic fertilizer replacement at various rates) on soil antibiotic resistome in paddy-upland rotation fields. Results revealed that a total of 100 ARG subtypes and 9 mobile genetic elements (MGEs) occurred in paddy-upland rotation soil, among which MDR-ARGs, MLSB-ARGs and tet-ARGs were the dominant resistance determinants. Long-term agricultural fertilization remarkably facilitated the vertical accumulation of ARGs, in particular that bla ampC and tetO in relative abundance showed significant enrichment with increasing depth. It's worth noting that slow release fertilizer significantly increased soil ARGs, when comparable to manure with 20% replacing amount, but chemical fertilizer had only slight impact on soil ARGs. Fertilization modes affected soil microbial communities, mainly concentrated in the surface layer, while the proportion of Proteobacteria with the highest abundance decreased gradually with increasing depth. Furthermore, microbial community and MGEs were further proved to be essential factors in regulating the variability of ARGs of different fertilization modes by structural equation model, and had strong direct influence (λ = 0.61, p < 0.05; λ = 0. 55, p < 0.01). The results provided scientific guidance for reducing the spreading risk of ARGs and control ARG dissemination in agricultural fertilization.

The integrated analysis of digestive physiology and gastrointestinal microbiota structure in Changle goose

Changle goose in Fujian, China is a rare genetic resource and in urgent need to be protected. Understanding the characteristics of digestive physiology and spatial variation of gastrointestinal microbiota is crucial for developing nutritional intervention strategies to improve intestinal health and production performance of goose. Hence, histomorphological assay was used for observing development status of proventriculus, jejunum, and cecum in 70-day-old Changle geese, whereas digesta from 6 alimentary canal locations (crop, proventriculus, gizzard, jejunum, cecum, and rectum) were collected for 16S rRNA gene sequencing and short chain fatty acids (SCFAs) quantitative analysis. The histomorphological observation indicated that the jejunum and cecum of Changle goose were well developed. The alpha diversity analysis revealed that, except rectum, microbiota in other noncecum sections were in high diversity as cecum. The Nonmetric MultiDimensional Scaling (NMDS) analysis showed that microbial community of proventriculus, gizzard, and jejunum formed a cluster, which distinctly discrete with the microbiota of the other gastrointestinal locations. Additionally, the proportions of Proteobacteria, Bacteroidota, and Campilobacterota at the phylum level and Lactobacillus, Streptococcus, Helicobacter, and Subdoligranulum at the genus level exhibited tremendous alternations among different gastrointestinal locations. The characteristic bacterial composition in each section was further disclosed by analyzing the core and feature Amplicon Sequence Variants (ASVs) and SCFAs pattern. Importantly, 7 body-weight-associated ASVs and 2 cecum-development-related ASVs were identified via correlation analysis. In a whole, our findings provided the first insights into the specialized digestive physiology of Changle geese and distinctive regional distribution of gastrointestinal microbiota, which laid the important foundation for improving growth performance through microbiota manipulation in geese.

Dietary sodium butyrate supplementation improves fish growth, intestinal microbiota composition, and liver health in largemouth bass (Micropterus salmoides) fed high-fat diets

The present study evaluated the effect of dietary sodium butyrate (NaBT) supplementation on the growth performance, intestinal microbiota composition, and liver health of largemouth bass Micropterus salmoides fed high-fat diets. Four isonitrogenous and isolipid diets were formulated: a high-fat diet and the high-fat diet supplemented by 0.05% NaBT, 0.1% NaBT, or 0.2% NaBT. Each diet was randomly distributed to triplicate tanks (200L) containing 30 fish (initial weight 4.0 ± 0.1 g) per tank. The experimental fish were fed to apparent satiation twice daily for 60 days. The orthogonal polynomial contrasts showed that the weight gain rate (WGR) and specific growth rate (SGR) increased linearly (P < 0.05) with increasing dietary NaBT levels (P < 0.05). No significant differences were found for feed intake (FI), feed conversion ratio (FCR), condition factor (CF), viscerosomatic index (VSI), and hepatosomatic index (HSI). There were no differences in the alpha diversity indices (including Operational Taxonomic Units, Chao index, and Simpson index) of intestinal microbiota between the various dietary groups (P > 0.05). For the intestinal microbiota composition, the proportion of Proteobacteria were linearly and cubically increased, whereas the proportion of Tenericutes and Mesomycoplasma were linearly and cubically decreased with the increase of dietary NaBT levels (P < 0.05). The increasing dietary NaBT levels led to significantly quadratic decrease of alanine aminotransferase (ALT) (P < 0.05), linear and quadratic decrease of aspartate aminotransferase (AST) (P < 0.05), and linear, quadratic, and cubic decrease of diamine oxidase (DAO) (P < 0.05). Hepatic triglyceride (TG) and total cholesterol (TCHO) contents decreased linearly and quadratically with the increase of dietary NaBT levels (P < 0.05). Increasing dietary NaBT levels linearly, quadratically, and cubically decreased the malondialdehyde (MDA) contents (P < 0.05). Total superoxide dismutase (T-SOD) and glutathione peroxidase (GPx) activity levels increased linearly with the increasing dietary NaBT levels (P < 0.05). As the dietary NaBT levels gradually increased, the relative expression of carnitine palmitoyl transferase (CPT1) and peroxisome proliferator-activated receptor α (PPARα) increased linearly, quadratically, and cubically (P < 0.05), while the relative expression of sterol regulatory element binding protein 1 (SREBP 1) decreased linearly, quadratically, and cubically (P < 0.05). The relative expression of tumor necrosis factor α (TNF-α) and cysteinyl aspartate specific protease 3 (Caspase 3) decreased linearly and quadratically with the increasing NaBT levels (P < 0.05). Pearson correlation analysis showed that fish growth was closely correlated with microbiota composition, hepatic lipid accumulation, hepatic antioxidant-related parameters, and hepatic gene expression (P < 0.05). These results indicated that NaBT could be used to alleviate the negative influence of high-fat diets on fish growth, intestinal microbiota homeostasis, and liver health.

Characterization of gut microbiota dysbiosis of diarrheic adult yaks through 16S rRNA gene sequences.

The ruminant gut microbial community has a strong impact on host health and can be altered during diarrhea disease. As an indigenous breed of the Tibetan Plateau, domestic yak displays a high diarrhea rate, but little research has been done to characterize the bacterial microbial structure in diarrheic yaks. In the present study, a total of 30 adult yaks, assigned to diarrhea (case, N = 15) and healthy (control, N = 15) groups, were subjected to gut microbiota profiling using the V3–V4 regions of the 16S rRNA gene. The results showed that the gut microbiome of the case group had a significant decrease in alpha diversity. Additionally, differences in beta diversity were consistently observed for the case and control groups, indicating that the microbial community structure was changed due to diarrhea. Bacterial taxonomic analysis indicated that the Bacteroidetes, Firmicutes, and Proteobacteria were the three most dominant phyla in both groups but different in relative abundance. Especially, the proportion of Proteobacteria in the case group was increased as compared with the control group, whereas Spirochaetota and Firmicutes were significantly decreased. At the genus level, the relative abundance of Escherichia-Shigella and Prevotellaceae_UCG-003 were dramatically increased, whereas that of Treponema, p-2534-18B5_gut_group, and Prevotellaceae_UCG-001 were observably decreased with the effect of diarrhea. Furthermore, based on our linear discriminant analysis (LDA) effect size (LEfSe) results, Alistipes, Solibacillus, Bacteroides, Prevotellaceae_UCG_003, and Bacillus were significantly enriched in the case group, while the other five genera, such as Alloprevotella, RF39, Muribaculaceae, Treponema, and Enterococcus, were the most preponderant in the control group. In conclusion, alterations in gut microbiota community composition were associated with yak diarrhea, differentially represented bacterial species enriched in case animals providing a theoretical basis for establishing a prevention and treatment system for yak diarrhea.

Dynamics of the Gut Microbiome and Transcriptome in Korea Native Ricefish (Oryzias latipes) during Chronic Antibiotic Exposure.

Antibiotics have been widely used to inhibit microbial growth and to control bacterial infection; however, they can trigger an imbalance in the gut flora of the host and dysregulate the host gene regulatory system when discharged into the aquatic environment. We investigated the effects of chronic exposure to a low concentration of erythromycin and ampicillin, focusing on gut microbiome and global gene expression profiles from Korea native ricefish (Oryzias latipes). The proportion of Proteobacteria (especially the opportunistic pathogen Aeromonas veronii) was significantly increased in the ricefish under the chronic exposure to erythromycin and ampicillin, whereas that of other bacterial phyla (i.e., Fusobacteria) decreased. In addition, the expression of genes involved in immune responses such as chemokines and immunocyte chemotaxis was significantly influenced in ricefish in the aquatic environment with antibiotics present. These results show that the internal microbial flora and the host gene expression are susceptible even at a low concentration of chronic antibiotics in the environment, supporting the importance of the appropriate use of antibiotic dose to maintain the sustainable and healthy aquaculture industry and water ecosystem.

Mesenchymal stem cell transplantation worsens intestinal inflammation and microenvironment in PI3Kγ-knockout mice

Considering the possible interaction between mesenchymal stem cells (MSCs) and PI3Kγ-associated drugs, we evaluated the efficacy and action mechanism of MSCs in the treatment of colitis in PI3Kγ-/- mice. Trinitro-benzene-sulfonic acid enema was used to create a colitis model, and MSCs were transplanted through the caudal vein to treat colitis in wild-type and PI3Kγ-/- mice. We sequenced microbial 16S rRNA genes in the colonic mucosa of PI3Kγ-/- and wild-type mice and quantified colonic IgA, IL-2, IL-10, IL-17A, occludin, and serum IgA. MSC transplantation led to a more serious reduction in the weight of trinitro-benzene-sulfonic acid-administered PI3Kγ-/- mice than that in wild-type mice. The disease activity index, pathological scoring, number of taxa in the colon, Berger–Parker index, I-index, proportion of Proteobacteria, and IgA level in the blood were higher in PI3Kγ-/- mice than in wild-type mice after MSC transplantation. The occludin and IL-10 levels in the colon tissues decreased before and after MSC transplantation in PI3Kγ-/- mice, whereas they were increased in wild-type mice The IL-17 level decreased in both wild-type and PI3Kγ-/- mice, with knockout mice showing a greater decrease. Therefore, MSC transplantation in PI3Kγ-/- mice led to increased numbers of exogenous pathogenic microorganisms and enhanced colitis that was difficult to relieve.

Protective effect of cinnamaldehyde on channel catfish infected by drug-resistant Aeromonas hydrophila

The protective effect of cinnamaldehyde on channel catfish infected by drug-resistant Aeromonas hydrophila CW strain was explored by observing the clinical signs and histopathology, measuring the cumulative mortality, serum biochemical and non-specific immune indicators, and intestinal microbiota in this study. The cumulative survival rate of the cinnamaldehyde within 14 days was significantly higher than that of the challenge group, which was 70% and 20%, respectively. Compared with the challenge group, the activities of lysozyme, superoxide dismutase, and glutathione peroxidase in the treatment group were increased, while there was no significant difference in catalase activity. Compared with the challenge group, the histopathology results showed that the injury of liver, spleen, and kidney was significantly alleviated after cinnamaldehyde treatment. The results of intestinal microbiota showed that the proportion of Proteobacteria in the challenge group was significantly increased, and the proportion of Aeromonas sp. reached 30% based on the analysis of species classification level. The composition of dominant species in the treatment group was similar to the control group. In conclusion, cinnamaldehyde increased the cumulative survival rate of channel catfish infected by A. hydrophila. It could protect channel catfish through improving the non-specific immune function of channel catfish, alleviating the pathological lesions of liver, spleen, kidney, and intestine, and maintaining the relative balance of the intestinal microbiota. Therefore, cinnamaldehyde could be a candidate drug for the treatment of A. hydrophila infection.

Yeast culture (Saccharomyces cerevisiae) and its active metabolites affect the cecal microbiome of broilers

Yeast cultures (YCs) are defined as promising feed additives that maintain the health of birds and improve growth performance by modulating gut microbiota. YCs contain effective metabolites such as glycine, fructose, inositol, galactose, and sucrose. This study investigated the effects of YCs and their effective metabolites on carcass traits and cecal microflora in broilers. A total of 280 one-day-old mixed-sex Arbor Acres broilers were randomly allocated to seven groups. The basal diet (control DZ) was supplemented with various proportions of glycine, fructose, inositol, galactose, and sucrose (Groups A, B, and C), 24-hour grown Saccharomyces cerevisiae cultures (Group D) (YC), and a commercial yeast culture product (SZ) at concentrations of 0.1% and 1% (Groups E and F). Bodyweight of broilers was correlated positively with proportions of Proteobacteria in Group C and Lactobacillus and Roseburia in Group B (P &lt;0.05). Broilers fed diets supplemented with YC or its active metabolites had the highest proportions of bacteria involved in nucleotide metabolism, and amino acid and carbohydrate metabolism. These results suggested that the dietary addition of YC could alter the proliferation of beneficial bacteria in broilers.

Microbial community structure analyses and cultivable denitrifier isolation of Myriophyllum aquaticum constructed wetland under low C/N ratio

With the rapid expansion of livestock production, the amount of livestock wastewater accumulated rapidly. Lack of biodegradable organic matter makes denitrification of livestock wastewater after anaerobic digestion more difficult. In this study, Myriophyllum aquaticum constructed wetlands (CWs) with efficient nitrogen removal performance were established under different carbon/nitrogen (C/N) ratios. Analysis of community composition reveals the change of M. aquaticum CWs in microbial community structure with C/N ratios. The proportion of Proteobacteria which is one of the dominant phyla among denitrifier communities increased significantly under low C/N ratio conditions. Besides, to obtain cultivable denitrifier that could be added into CWs in situ, 33 strains belonging to phylum Proteobacteria were isolated from efficient M. aquaticum CWs, while the best-performing denitrification strain M3-1 was identified as Bacillus velezensis JT3-1 (GenBank No. CP032506.1). Redundancy analysis and quadratic models showed that C/N ratio had significant effects on disposal of nitrate (NO3−-N) and the strains isolated could perform well in denitrification when C/N ratio is relatively low. In addition, they have relatively wide ranges of carbon sources, temperature and a high NO3− removal rate of 9.12 mg/(L·hr) at elevated concentrations of 800 mg/L nitrate. Thus, strains isolated from M. aquaticum CWs with low C/N ratio have a practical application value in the treatment of nitrate-containing wastewater. These denitrifying bacteria could be added to CWs to enhance nitrogen removal efficiency of CWs for livestock wastewater with low C/N ratio in the future.

Characteristic Analysis of nirS Denitrifying Bacterial Community in Lijiahe Reservoir During Stratification

To explore the composition of the nirS denitrifying bacterial community during stratification in spring(March to May) in a drinking water reservoir and its relationship with water quality, the water quality and relative abundance and structure of the denitrifying bacterial community were analyzed using in-situ monitoring coupled with Illumina high-throughput sequencing technology in the Lijiahe Reservoir. The results showed that:① through high-throughput sequencing, 4 phyla and 13 genera were identified. The dominant bacterial phylum was Proteobacteria, and its relative abundance was between 52.5% and 70.6%. The overall trend of the relative abundance of Proteobacteria decreased on the time scale (P<0.05), and its relative abundance in the surface and middle layers was higher than that of the bottom layer on the spatial scale (P<0.05). There was no difference in the proportion of Proteobacteria between the surface and middle layers (P>0.05), and the abundance of its bottom layer was relatively stable; eight genera of bacteria with denitrification function were identified, among which the dominant bacterial genera (relative abundance>1%) were Dechloromonas and Pseudomonas. The relative abundance of Dechloromonas showed a trend of first decreasing and then increasing on the time scale, whereas the relative abundance of Pseudomonas showed a trend of increasing first and then decreasing on the time scale. There were no differences on the spatial scale between these two genera (P>0.05); the changes in bacterial diversity and abundance were basically similar, with a trend of first increasing and then decreasing on the time scale. The highest diversity and abundance of the bacterial community gradually increased with increasing depth on the spatial scale. ② ρ(TN) of the reservoir during stratification was 2.35-2.91 mg·L-1, and the nitrogen pollution was more serious. In March and April, ρ(TN) on the vertical scale was basically similar and showed a decreasing trend. In May, the content of total nitrogen was higher than that in March and April, and the highest value of total nitrogen content occurred in the surface layer. ③ Redundancy analysis showed that water temperature, dissolved oxygen, nitrate, and ammonia nitrogen were the main driving factors, and ammonia nitrogen showed a significantly negative correlation with Dechlormonas. In summary, the study of nirS-type denitrification communities and related influencing factors will contribute to analyzing the characteristics of denitrifying bacterial community changes in a micro-polluted drinking water reservoir and provide a theoretical research basis for the biological remediation of nitrogen pollution in such reservoirs in the future.

Effects of biochar dosage on treatment performance, enzyme activity and microbial community in aerated constructed wetlands for treating low C/N domestic sewage

Biochar (BC) has been widely utilized in constructed wetland (CW) for intensifying the removal of pollutants from low carbon/nitrogen (C/N) wastewater. However, there are knowledge gaps about the optimal proportion of BC as an external carbon substrate. This study developed four sets of aerated vertical flow (VF) CWs with different BC amendment proportions (0%, 25%, 50%, 75%) to explore the influence of BC dosage on the treatment performance, enzyme activity and microbial community. The results showed that all CWs achieved better COD (above 90%) and NH 4 + -N (above 99%) removal due to adequate oxygen supplement, while the best TN removal (67%) was obtained in CW with 50% BC addition. TP removal ascended gradually with the increasing BC amendment proportion. The activity of enzymes and the proportion of Proteobacteria and Patescibacteria at the phylum level were appreciably enhanced with the addition of BC. • 50% biochar addition obtained the highest total nitrogen removal. • 75% biochar addition achieved the better total phosphorus removal. • Biochar addition in wetland systems increased the nitrous oxide emission. • Biochar addition enhanced enzyme activity and altered microbial community composition.

Effect of the course of treatment with broad-spectrum antibiotics on intestinal flora and short-chain fatty acids in feces of very low birth weight infants: a prospective study.

To study the effect of the course of treatment with broad-spectrum antibiotics on intestinal flora and short-chain fatty acids (SCFAs) in feces of very low birth weight (VLBW) infants. A total of 29 VLBW infants who were admitted to the Neonatal Diagnosis and Treatment Center of Children's Hospital Affiliated to Chongqing Medical University from June to December 2020 were enrolled as subjects for this prospective study. According to the course of treatment with broad-spectrum antibiotics, they were divided into two groups: ≤7 days (n=9) and >7 days (n=20). Fecal samples were collected on days 14 and 28 of hospitalization, and 16S rDNA high-throughput sequencing and gas chromatography-mass spectrometry were used to analyze the flora and SCFAs in fecal samples. There was a significant reduction in Chao index of the intestinal flora in the ≤7 days group and the >7 days group from week 2 to week 4 (P<0.05). In the ≤7 days group, there were significant increases in the proportions of Firmicutes and Clostridium_sensu_stricto_1 and a significant reduction in the proportion of Proteobacteria from week 2 to week 4 (P<0.05). At week 4, compared with the ≤7 days group, the >7 days group had significant reductions in the proportions of Firmicutes and Clostridium_sensu_stricto_1 and a significant increase in the proportion of Proteobacteria (P<0.05), as well as significant reductions in the content of isobutyric acid and valeric acid (P<0.05). The course of treatment with broad-spectrum antibiotics can affect the abundance, colonization, and evolution of intestinal flora and the content of their metabolites SCFAs in VLBW infants. The indication and treatment course for broad-spectrum antibiotics should be strictly controlled in clinical practice.