16S rRNA Gene Sequence Analysis Research Articles

Membrane-anchoring selenophene viologens for antibacterial photodynamic therapy against periodontitis via restoring subgingival flora and alleviating inflammation

Antibacterial photodynamic therapy (aPDT) has emerged as a promising strategy for treating periodontitis. However, the weak binding of most photosensitizers to bacteria and the hypoxic environment of periodontal pockets severely hamper the therapeutic efficacy. Herein, two novel oxygen-independent photosensitizers are developed by introducing selenophene into viologens and modifying with hexane chains (HASeV) or quaternary ammonium chains (QASeV), which improve the adsorption to bacteria through anchoring to the negatively charged cell membrane. Notably, QASeV binds only to the bacterial surface of Porphyromonas gingivalis and Fusobacterium nucleatum due to electrostatic binding, but HASeV can insert into their membrane by strong hydrophobic interactions. Therefore, HASeV exhibits superior antimicrobial activity and more pronounced plaque biofilm disruption than QASeV when combined with light irradiation (MVL-210 photoreactor, 350–600 nm, 50 mW/cm2), and a better effect on reducing the diversity and restoring the structure of subgingival flora in periodontitis rat model was found through 16S rRNA gene sequencing analysis. The histological and Micro-CT analyses reveal that HASeV-based aPDT has a better therapeutic effect in reducing periodontal tissue inflammation and alveolar bone resorption. This work provides a new strategy for the development of viologen-based photosensitizers, which may be a favorable candidate for the aPDT against periodontitis.

Species-level Microbiota of Biting Midges and Ticks from Poyang Lake.

The purpose of this study was to investigate the bacterial communities of biting midges and ticks collected from three sites in the Poyang Lake area, namely, Qunlu Practice Base, Peach Blossom Garden, and Huangtong Animal Husbandry, and whether vectors carry any bacterial pathogens that may cause diseases to humans, to provide scientific basis for prospective pathogen discovery and disease prevention and control. Using a metataxonomics approach in concert with full-length 16S rRNA gene sequencing and operational phylogenetic unit (OPU) analysis, we characterized the species-level microbial community structure of two important vector species, biting midges and ticks, including 33 arthropod samples comprising 3,885 individuals, collected around Poyang Lake. A total of 662 OPUs were classified in biting midges, including 195 known species and 373 potentially new species, and 618 OPUs were classified in ticks, including 217 known species and 326 potentially new species. Surprisingly, OPUs with potentially pathogenicity were detected in both arthropod vectors, with 66 known species of biting midges reported to carry potential pathogens, including Asaia lannensis and Rickettsia bellii, compared to 50 in ticks, such as Acinetobacter lwoffii and Staphylococcus sciuri. We found that Proteobacteria was the most dominant group in both midges and ticks. Furthermore, the outcomes demonstrated that the microbiota of midges and ticks tend to be governed by a few highly abundant bacteria. Pantoea sp7 was predominant in biting midges, while Coxiella sp1 was enriched in ticks. Meanwhile, Coxiella spp., which may be essential for the survival of Haemaphysalis longicornis Neumann, were detected in all tick samples. The identification of dominant species and pathogens of biting midges and ticks in this study serves to broaden our knowledge associated to microbes of arthropod vectors. Biting midges and ticks carry large numbers of known and potentially novel bacteria, and carry a wide range of potentially pathogenic bacteria, which may pose a risk of infection to humans and animals. The microbial communities of midges and ticks tend to be dominated by a few highly abundant bacteria.

Integrated microbiome and metabolome analyses reveal the effects of low pH on intestinal health and homeostasis of crayfish (Procambarus clarkii)

Low pH (LpH) poses a significant challenge to the health, immune response, and growth of aquatic animals worldwide. Crayfish (Procambarus clarkii) is a globally farmed freshwater species with a remarkable adaptability to various environmental stressors. However, the effects of LpH stress on the microbiota and host metabolism in crayfish intestines remain poorly understood. In this study, integrated analyses of antioxidant enzyme activity, histopathological damage, 16S rRNA gene sequencing, and liquid chromatography-mass spectrometry (LC-MS) were performed to investigate the physiology, histopathology, microbiota, and metabolite changes in crayfish intestines exposed to LpH treatment. The results showed that LpH stress induced obvious changes in superoxide dismutase and catalase activities and histopathological alterations in crayfish intestines. Furthermore, 16S rRNA gene sequencing analysis revealed that exposure to LpH caused significant alterations in the diversity and composition of the crayfish intestinal microbiota at the phylum and genus levels. At the genus level, 14 genera including Bacilloplasma, Citrobacter, Shewanella, Vibrio, RsaHf231, Erysipelatoclostridium, Anaerorhabdus, Dysgonomonas, Flavobacterium, Tyzzerella, Brachymonas, Muribaculaceae, Propionivibrio, and Comamonas, exhibited significant differences in their relative abundances. The LC-MS analysis revealed 859 differentially expressed metabolites in crayfish intestines in response to LpH, including 363 and 496 upregulated and downregulated metabolites, respectively. These identified metabolites exhibited significant enrichment in 24 Kyoto Encyclopedia of Genes and Genomes pathways (p < 0.05), including seven and 17 upregulated and downregulated pathways, respectively. These pathways are mainly associated with energy and amino acid metabolism. Correlation analysis revealed a strong correlation between the metabolites and intestinal microbiota of crayfish during LpH treatment. These findings suggest that LpH may induce significant oxidative stress, intestinal tissue damage, disruption of intestinal microbiota homeostasis, and alterations in the metabolism in crayfish. These findings provide valuable insights into how the microbial and metabolic processes of crayfish intestines respond to LpH stress.

Complete genome sequence of a novel Prescottella sp. R16 isolate from deep-sea sediments in the western Pacific.

Prescottella, a distinct genus separate from Rhodococcus, has garnered attention for its adaptability and ecological versatility. In this study, a Gram-stain positive and ovoid-rod shaped the actinobacterium strain R16 was isolated from deep-sea sediment (with a depth of 6,310m) in the Western Pacific. On the basis of 16S rRNA gene sequence analysis, average nucleotide identity and phylogenomic analysis, strain R16 clearly represents a novel species within the genus Prescottella. Genomic analyses indicate Prescottella sp. R16 contains a circular chromosome of 4,531,251 bp with an average GC content of 68.9%, 4,208 protein-coding genes, 51 tRNA genes, and 12 rRNA operons. Additionally, four CRISPRs and 24 genomic islands are also identified. The presence of rich categories related to catalytic activity, membrane part and metabolic process highlights their involvement in cellular component, biological process, and molecular function. The genome sequence of strain R16 also revealed the presence of 13 putative biosynthetic gene clusters for secondary metabolites, including those for ε-Poly-L-lysine, ectoine, heterobactin, isorenieratene and corynecin, suggesting its potential for antibiotic production and warranting further exploration.

Vibrio misgurnus sp. nov., a new pathogen of cultured loach (Misgurnus anguillicaudatus), closely related to Vibrio cholerae

An epidemic with petechial hemorrhages on the body surface recently occurred in the farmed loach (Misgurnus anguillicaudatus) in Sichuan province. Multiple antibiotic treatments were ineffective against this epidemic. This study aims to elucidate the cause of the disease. Two bacterial strains, GVCT and VCS were isolated from diseased loach. Experimental infections with these two isolates resulted in marked symptoms in the loach consistent with those observed in natural outbreaks. The taxonomic status was determined by phenotypic assay, chemotaxonomic and whole genome analysis. Strain GVCT exhibited unique phenotypic characteristics, including its β-glucosidase activity and inability to utilize casein and starch, which distinguished it from Vibrio cholerae ATCC14035T. Paired 16S rRNA gene sequence analysis confirmed that strains GVCT and VCS belong to the genus Vibrio. The primary fatty acids of strain GVCT are C16:0, summed Feature 3 (C16:1ω7c/C16:1ω6c), and summed Feature 8 (C18:1 ω6c/C18:1 ω7c), and the major respiratory quinone is Q-8. The predominant lipids were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), aminophospholipids (APL) and an unidentified phosphoglycolipid designated PL1. Strains GVCT and VCS have genome sizes of 3.2 Mb and 3.3 Mb, as well as GC contents of 47.0 and 47.2 mol% respectively. Phylogenomic and whole-genome nucleotide sequence analyses further confirmed that these isolates represent a novel species of the genus Vibrio, for which the name Vibrio misgurnus sp. nov. is proposed, with strain GVCT as the type strain. Strain GVCT was found to be highly pathogenic to loach, causing high mortality and posing a threat to loach aquaculture, with a half-lethal dose (LD50) of strain GVCT for loach is 8.96 × 106 CFU/mL, and it was resistant to drugs such as enrofloxacin, doxycycline hydrochloride, flumequine, neomycin sulphate and florfenicol.

An inhibitory immunoreceptor Allergin-1 regulates the intestinal dysbiosis and barrier function in mice.

The intestinal barrier consists of mucosal, epithelial, and immunological barriers and serves as a dynamic interface between the host and its environment. Disruption of the intestinal barrier integrity is a leading cause of various gastrointestinal diseases, such as inflammatory bowel disease. The homeostasis of the intestinal barrier is tightly regulated by crosstalk between gut microbes and the immune system; however, the implication of the immune system on the imbalance of gut microbes that disrupts barrier integrity remains to be fully elucidated. An inhibitory immunoglobulin-like receptor, Allergin-1, is expressed on mast cells and dendritic cells and inhibits Toll-like receptor (TLR)-2 and TLR-4 signaling in these cells. Since TLRs are major sensors of microbiota and are involved in local epithelial homeostasis, we investigated the role of Allergin-1 in maintaining intestinal homeostasis. Allergin-1-deficient (Milr1-/-) mice exhibited more severe dextran sulfate sodium (DSS)-induced colitis than did wild-type (WT) mice. Milr1-/- mice showed an enhanced intestinal permeability than did WT mice even before DSS administration. Treatment of Milr1-/- mice with neomycin, but not ampicillin, restored intestinal barrier integrity. The 16S rRNA gene sequencing analysis demonstrated that Bifidobacterium pseudolongum was the dominant bacteria in Milr1-/- mice after treatment with ampicillin. Although the transfer of B. pseudolongum to germ-free WT mice had no effect on intestinal permeability, its transfer into ampicillin-treated WT mice enhanced intestinal permeability. These results demonstrated that Allergin-1 deficiency enhanced intestinal dysbiosis with expanded B. pseudolongum, which contributes to intestinal barrier dysfunction in collaboration with neomycin-sensitive and ampicillin-resistant microbiota.

Microbial-Transferred Metabolites and Improvement of Biological Activities of Green Tea Catechins by Human Gut Microbiota.

Green tea catechins (GTCs) are dietary polyphenols with broad bioactivities that undergo extensive microbial metabolism in the human gut. However, microbial-transferred metabolites and their health benefits are not fully understood. Herein, the microbial metabolism of GTCs by human fecal microbiota and dynamic alteration of the microbiota were integrally investigated via in vitro anaerobic fermentation. The results showed that the human gut microbiota exhibited a strong metabolic effect on GTCs via UHPLC-MS/MS analysis. A total of 35 microbial-transferred metabolites were identified, far more than were identified in previous studies. Among them, five metabolites, namely EGCG quinone, EGC quinone, ECG quinone, EC quinone, and mono-oxygenated EGCG, were identified for the first time in fermented GTCs with the human gut microbiota. Consequently, corresponding metabolic pathways were proposed. Notably, the antioxidant, α-amylase, and α-glucosidase inhibitory activities of the GTCs sample increased after fermentation compared to those of the initial unfermented sample. The results of the 16S rRNA gene sequence analysis showed that the GTCs significantly altered gut microbial diversity and enriched the abundancy of Eubacterium, Flavonifractor, etc., which may be further involved in the metabolisms of GTCs. Thus, these findings contribute to a better understanding of the interactions between GTCs and gut microbiota, as well as the health benefits of green tea consumption.

Esmolol increases the fecal abundance of Lactobacillus in a rat model of sepsis

BackgroundDisorders of the gut microbiome could be responsible for the progression of multiple organ dysfunction syndrome. In this study, we examined the effect of esmolol on the gut microbiome in a rat model of sepsis induced by cecal ligation and puncture (CLP).MethodsThe animals (n = 32) were randomly divided into 3 groups: Sham group (sham operation + normal saline treatment, n = 8), CLP group (cecal ligation and puncture + normal saline treatment, n = 12), and CLP + ESM group (cecal ligation and puncture + esmolol treatment, n = 12). After 24 h, feces in the colon were collected for 16S rRNA gene sequencing and nitric oxide analysis. In addition, colon was removed for immunohistochemical staining of inducible nitric oxide synthase (iNOS).ResultsFour rats in the CLP group and two rats in the CLP + ESM group died. The abundance of Lactobacillus in the CLP + ESM group was higher than CLP group (P = 0.048). In the linear discriminant analysis effect size analysis, Norank f Muribaculaceae, Escherichia–Shigella and Lactobacillus were the predominant bacteria in the Sham group, CLP group and CLP + ESM group, respectively. The iNOS expression in colonocytes stained by brown in the CLP group were much more than Sham group (P = 0.001). Compared to CLP group, the iNOS expression in colonocytes reduced after esmolol treatment (P = 0.013). The concentration of nitric oxide in colon feces was different in Sham group, CLP group and CLP + ESM group (1.31 ± 0.15μmmol/l vs. 1.98 ± 0.27μmmol/l vs. 1.51 ± 0.14μmmol/l, P = 0.001). In addition, the concentration of nitric oxide in CLP group was higher than Sham group (P = 0.001) or CLP + ESM group (P = 0.001).ConclusionsEsmolol increased the fecal abundance of Lactobacillus in a rat model of sepsis. Moreover, esmolol reduced the iNOS expression of colonocytes and the nitric oxide concentration of colon feces.

Lactiplantibacillus paraxiangfangensis sp. nov., isolated from traditional Chinese pickle.

Three Gram-stain-positive bacterial strains (designated 231-9T, 142-6 and 463-4) were isolated from traditional Chinese pickle, and were characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strains 231-9T, 142-6 and 463-4 were phylogenetically related to the type strains of Lactiplantibacillus xiangfangensis, Lactiplantibacillus garii, Lactiplantibacillus carotarum, Lactiplantibacillus plajomi and Lactiplantibacillus modestisalitolerans, having 98.6-99.9 % 16S rRNA gene sequence similarities. Strains 231-9T, 142-6 and 463-4 were most closely related to the type strain of L. xiangfangensis, having 99.9 % 16S rRNA gene, 95.6 % pheS, 99.4 % rpoA and 98.2 % concatenated pheS and rpoA sequence similarities. Relatively low pheS (95.6 %) sequence similarity indicated that strain 231-9T should be further identified. Strain 231-9T shared 99.7-99.9 % average nucleotide identity (ANI) and 98.8-98.9 % digital DNA-DNA hybridization (dDDH) values with strains 142-6 and 463-4, indicating that they belonged to the same species. The ANI and dDDH values between strain 231-9T and L. xiangfangensis LMG 26013T were 92.4-92.9 and 49.6 %, respectively, less than the threshold for species demarcation (95-96% ANI and 70 % dDDH values, respectively), indicating that strains 231-9T, 142-6 and 463-4 represented a novel species within the genus Lactiplantibacillus. Acid production from d-ribose, d-adonitol, d-galactose and lactose, activity of β-galactosidase and β-glucosidase, Voges-Proskauer reaction, hydrolysis of hippurate, resistance to 5 µg ml-1 erythromycin, 100 µg ml-1 tetracycline hydrochloride, 50 µg ml-1 bacitracin, 300 µg ml-1 each of gentamicin sulphate, streptomycin sulphate and neomycin sulphate, tolerance to 6 % NaCl could distinguish strains 231-9T, 142-6 and 463-4 from L. xiangfangensis 3.1.1T. Based upon the data of polyphasic characterization obtained in the present study, a novel species, Lactiplantibacillus paraxiangfangensis sp. nov., is proposed and the type strain is 231-9T (=JCM 36258T=CCTCC AB 2023133T).

Co-occurrence of Heavy Metal and Antibiotics Resistance Traits in Bacteria Isolated from Poultry Droppings and Soil in Badagry, Lagos

Background: Heavy metal and antibiotic resistance are two pressing global concerns affecting the agri-cultural and food sectors. Moreover, heavy metals tend to select antibiotic resistance in the absence of antibiotics. This study aimed to isolate, screen and identify heavy metal-resistant bacteria that can resist multiple antibiotics in agricultural settings. Methods: Using standard cultural techniques, twenty-six heavy metal tolerant bacteria were isolated from poultry droppings and soil samples collected from Lagos State Food Processing Centre located at Badagry, Lagos. The isolates were presumptively identified by their morphological characteristics and subjected to antibiotics sensitivity test using the disc diffusion method. The identities of isolates exhib-iting multi-drug resistance (MDR) among the metal tolerance isolates were authenticated using 16S rRNA gene sequence analysis. Results: All isolates recovered from the soil sample tolerated 3 mM of lead and nickel, while isolates from poultry droppings recorded the least tolerable concentrations of 1 mM and 2 mM of cadmium and lead, respectively. Each isolate exhibited resistance to at least a group of antibiotics phenotypically. Resistance to colistin (42.31%) was the highest among the isolates, closely followed by chlorampheni-col (23.08%), while gentamicin (3.85%) was the lowest among the isolates. However, six isolates were shown to be MDR strain, and they were identified as Bacillus pumilus, Bacillus cereus, Brevundimonas naejangsanensis, Pseudochrobactrum asaccharolyticum, Pseudochrobactrum saccharolyticum and Lysinibacillus xylanilyticus. Conclusion: This study further draws attention to the increasing dual resistance of bacteria to heavy metals and antibiotics, which may hinder the fight against antimicrobial resistance in agricultural set-tings

Study on the intervention effect of Epimedium before and after suet-oil-processed on kidney yang deficiency rats based on intestinal flora and fecal metabolomics

Epimedium is a Chinese herbal medicine commonly used in clinical practice to reinforce yang. Previous studies have shown that Epimedium fried with suet oil based has the best effect on warming kidney and promoting yang. Evidence suggests a relationship between kidney yang deficiency syndrome (KYDS) and metabolic disorders of the intestinal microflora. However, the specific interaction between KYDS and the intestinal microbiome, as well as the internal regulatory mechanism of the KYDS intestinal microbiome regulated by Epimedium fried with suet oil, remain unclear. The purpose of this study was to investigate the regulatory effects of different processed products of Epimedium on intestinal microflora and metabolites in rats with kidney yang deficiency, and to reveal the processing mechanism of Epimedium fried with suet oil warming kidney and helping yang. 16S rRNA and LC-MS/MS technology were used to detect fecal samples. Combined with multivariate statistical analysis, differential intestinal flora and metabolites were screened. Then the content of differential bacteria was then quantified using quantitative real-time fluorescence PCR. Furthermore, the correlation between differential bacterial flora and metabolites was analyzed using Spearman's method. The study found that the composition of intestinal flora in rats with kidney yang deficiency changed compared to healthy rats. Epimedium fried with suet oil could increase the levels of beneficial bacteria, while significantly reducing the levels of harmful bacteria. Real-time quantitative PCR results were consistent with 16S rRNA gene sequencing analysis. Fecal metabolomics revealed that KYDS was associated with 30 different metabolites, involving metabolic pathways steroid hormone biosynthesis etc. Moreover, differential bacteria were closely correlated with potential biomarkers. Epimedium could improve metabolic disorders associated with KYDS by acting on the intestinal flora, with Epimedium fried with suet oil demonstrating the most effective regulatory effect. Its potential mechanism may involve the regulation of abnormal metabolism and the impact on the diversity and structure of the intestinal flora.

Novel insights into the synergetic degradation of pyrene by microbial communities from mangroves in China

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (HMW-PAHs). It is a ubiquitous, persistent, and carcinogenic environmental contaminant that has raised concern worldwide. This research explored synergistic bacterial communities for efficient pyrene degradation in seven typical Southern China mangroves. The bacterial communities of seven typical mangroves were enriched by pyrene, and enriched bacterial communities showed an excellent pyrene degradation capacity of > 95% (except for HK mangrove and ZJ mangrove). Devosia, Hyphomicrobium, Flavobacterium, Marinobacter, Algoriphahus, and Youhaiella all have significant positive correlations with pyrene (R>0, p < 0.05) by 16SrRNA gene sequencing and metagenomics analysis, indicated that these genera play a vital role in pyrene metabolism. Meanwhile, the functional genes were involved in pyrene degradation that was enriched in the bacterial communities, including the genes of nagAa, ndoR, pcaG, etc. Furthermore, the analyses of functional genes and binning genomes demonstrated that some bacterial communities as a unique teamwork to cooperatively participate in pyrene degradation. Interestingly, the genes related to biogeochemical cycles were enriched, such as narG , soxA, and cyxJ, suggested that bacterial communities were also helpful in maintaining the stability of the ecological environment. In addition, some novel species with pyrene-degradation potential were identified in the pyrene-degrading bacterial communities, which can enrich the resource pool of pyrene-degrading strains. Overall, this study will help develop further research strategies for pollutant removal.

Lactobacillus juensis sp. nov. and Lactobacillus rizhaonensis sp. nov., isolated from the gut of honeybee (Apis mellifera).

Four lactic acid bacteria, designated F690T, F697, F790T and F769-2, were isolated from the gut of honeybee (Apis mellifera). Results of 16S rRNA gene sequence analysis indicated that strains F690T and F697 were phylogenetically related to the type strains of Lactobacillus kimbladii, Lactobacillus laiwuensis, Lactobacillus kullabergensis and Lactobacillus huangpiensis, having 99.1-99.6 % 16S rRNA gene sequence similarities; and that strains F790T and F769-2 were most closely related to the type strain of Lactobacillus melliventris, having 99.2-99.3 % 16S rRNA gene sequence similarities. The phylogenies based on concatenated pheS, rpoA, gyrB, hsp60, recA, rpoB and tuf sequences and based on whole genome sequences were identical to that based on 16S rRNA gene sequences. Strains F690T and F697 exhibited the highest average nucleotide identity (ANI; 92.1-93.2 %), digital DNA-DNA hybridization (dDDH; 50-50.1 %) and average amino acid identity (AAI; 94.9-95.1 %) values with L. kimbladii Hma2NT. Strains F790T and F769-2 had the highest ANI (93.1-94 %), dDDH (54.4 %) and AAI (94.4-94.7 %) values with L. melliventris Hma8NT. Based upon the data obtained in the present study, two novel species, Lactobacillus juensis sp. nov. and Lactobacillus rizhaonensis sp. nov., are proposed and the type strains are F690T (=JCM 36259T=CCTCC AB 2023131T) and F790T (=JCM 36260T=CCTCC AB 2023132T), respectively.

Effect of Fermented Milk Supplemented with Nisin or Plantaricin Q7 on Inflammatory Factors and Gut Microbiota in Mice.

Lactic-acid-bacteria-derived bacteriocins are used as food biological preservatives widely. Little information is available on the impact of bacteriocin intake with food on gut microbiota in vivo. In this study, the effects of fermented milk supplemented with nisin (FM-nisin) or plantaricin Q7 (FM-Q7) from Lactiplantibacillus plantarum Q7 on inflammatory factors and the gut microbiota of mice were investigated. The results showed that FM-nisin or FM-Q7 up-regulated IFN-γ and down-regulated IL-17 and IL-12 in serum significantly. FM-nisin down-regulated TNF-α and IL-10 while FM-Q7 up-regulated them. The results of 16S rRNA gene sequence analysis suggested that the gut microbiome in mice was changed by FM-nisin or FM-Q7. The Firmicutes/Bacteroides ratio was reduced significantly in both groups. It was observed that the volume of Akkermansia_Muciniphila was significantly reduced whereas those of Lachnospiraceae and Ruminococcaceae were increased. The total number of short-chain fatty acids (SCFAs) in the mouse feces of the FM-nisin group and FM-Q7 group was increased. The content of acetic acid was increased while the butyric acid content was decreased significantly. These findings indicated that FM-nisin or FM-Q7 could stimulate the inflammation response and alter gut microbiota and metabolic components in mice. Further in-depth study is needed to determine the impact of FM-nisin or FM-Q7 on the host's health.

Polycladomyces zharkentensis sp. nov., a novel thermophilic cellulose- and starch-degrading member of the Bacillota from a geothermal aquifer in Kazakhstan.

A thermophilic, aerobic and heterotrophic filamentous bacterium, designated strain ZKZ2T, was isolated from a pipeline producing hydrothermal water originating from a >2.3 km deep subsurface geothermal source in Zharkent, Almaty region, Kazakhstan. The isolate was Gram-stain-positive, non-motile, heat-resistant and capable of producing a variety of extracellular hydrolases. Growth occurred at temperatures between 55 and 75 °C, with an optimum around 70 °C, and at pH values between 5.5 and 9.0, with an optimum at pH 7.0-7.5 with the formation of aerial mycelia; endospores were produced along the aerial mycelium. The isolate was able to utilize the following substrates for growth: glycerol, l-arabinose, ribose, d-xylose, d-glucose, d-fructose, d-mannose, rhamnose, d-mannitol, methyl-d-glucopyranoside, aesculin, salicin, cellobiose, maltose, melibiose, sucrose, trehalose, melezitose, raffinose, starch, turanose and 5-keto-gluconate. Furthermore, it was able to hydrolyse carboxymethylcellulose, starch, skimmed milk, Tween 60 and Tween 80. The major cellular fatty acids were iso-C15 : 0, iso-C17 : 0, iso-C16 : 0 and C16 : 0. Our 16S rRNA gene sequence analysis placed ZKZ2T within the genus Polycladomyces, family Thermoactinomycetaceae, with the highest similarity to the type species Polycladomyces abyssicola JIR-001T (99.18 % sequence identity). Our draft genome sequence analysis revealed a genome size of 3.3 Mbp with a G+C value of 52.5 mol%. The orthologous average nucleotide identity value as compared to that of its closest relative, P. abyssicola JIR-001T, was 90.23 %, with an in silico DNA-DNA hybridization value of 40.7 %, indicating that ZKZ2T represents a separate genome species. Based on the phenotypic and genome sequence differences from the other two Polycladomyces species, we propose that strain ZKZ2T represents a novel species, for which we propose the name Polycladomyces zharkentensis sp. nov. The type strain is ZKZ2T (=CECT 30708T=KCTC 43421T).

Impact of vaginal microecological differences on pregnancy outcomes and endometrial microbiota in frozen embryo transfer cycles.

This prospective study investigates the correlation between vaginal microecology and pregnancy outcomes and explores their impact on endometrial microbiota composition during frozen embryo transfer (FET) cycles. Additionally, the impact of transvaginal Lactobacillus supplementation on reproductive outcomes in patients with previous failed cycles was assessed. A total of 379 patients undergoing FET at a reproductive medicine center were categorized into clinical pregnancy (CP), miscarriage (MISC), and non-pregnant (NP) groups. Vaginal specimens were collected for microecological evaluation prior to embryo transfer. Endometrial microbiota samples were obtained during embryo transfer for 16S rRNA gene sequencing analysis to assess endometrial microbiota composition. Vaginal microecological indicators, including pH, Lactobacillus dominance, and leukocyte esterase activity, were measured. Transvaginal Lactobacillus supplementation was investigated in 60 patients with previous failed cycles. Vaginal microecology significantly correlated with pregnancy outcomes, with normal microecology associated with a higher clinical pregnancy rate. Vaginal pH and leukocyte esterase activity were significantly associated with clinical pregnancy. Furthermore, vaginal microecological differences significantly impacted endometrial microbiota composition. However, no significant differences were observed in endometrial microbiota composition among the CP, MISC, and NP groups. Notably, transvaginal Lactobacillus supplementation increased the clinical pregnancy rate without affecting the miscarriage rate. This study highlights that normal vaginal microecology, characterized by lower pH and leukocyte esterase negativity, is associated with a higher likelihood of clinical pregnancy following FET. Importantly, vaginal microecological differences influence endometrial microbiota composition. Moreover, transvaginal Lactobacillus supplementation appears promising in improving clinical pregnancy rates in patients with previous failed cycles. These findings contribute to a better understanding of the interplay between vaginal and endometrial microbiota and offer potential interventions to enhance reproductive success in assisted reproductive technologies.

Electroacupuncture at ST25 corrected gut microbial dysbiosis and SNpc lipid peroxidation in Parkinson's disease rats.

Parkinson's disease (PD) remains one kind of a complex, progressive neurodegenerative disease. Levodopa and dopamine agonists as widely utilized PD therapeutics have not shown significant positive long-term outcomes. Emerging evidences indicate that electroacupuncture (EA) have potential effects on the therapy of nervous system disorders, particularly PD, but its specific underlying mechanism(s) remains poorly understood, leading to the great challenge of clinical application and management. Previous study has shown that acupuncture ameliorates PD motor symptoms and dopaminergic neuron damage by modulating intestinal dysbiosis, but its intermediate pathway has not been sufficiently investigated. A rat model of PD was induced using rotenone. The therapeutic effect of EA on PD was assessed using the pole and rotarod tests and immunohistostaining for tyrosine hydroxylase (TH) in the substantia nigra (SN) of brain. The role of gut microbiota was explored using 16S rRNA gene sequencing and metabonomic analysis. PICRUSt2 analysis, lipidomic analysis, LPS and inflammatory factor assays were used for subsequent exploration and validation. Correlation analysis was used to identify the key bacteria that EA regulates lipid metabolism to improve PD. The present study firstly reappeared the effects of EA on protecting motor function and dopaminergic neurons and modulation of gut microbial dysbiosis in rotenone-induced PD rat model. EA improved motor dysfunction (via the pole and rotarod tests) and protected TH+ neurons in PD rats. EA increased the abundance of beneficial bacteria such as Lactobacillus, Dubosiella and Bifidobacterium and decreased the abundance of Escherichia-Shigella and Morganella belonging to Pseudomonadota, suggesting that the modulation of gut microbiota by EA improving the symptoms of PD motility via alleviating LPS-induced inflammatory response and oxidative stress, which was also validated by various aspects such as microbial gene functional analysis, fecal metabolomics analysis, LPS and inflammatory factor assays and SNpc lipidomics analysis. Moreover, correlation analyses also verified strong correlations of Escherichia-Shigella and Morganella with motor symptoms and SNpc lipid peroxidation, explicating targets and intermediate pathways through which EA improve PD exercise symptom. Our results indicate that the improvement of motor function in PD model by EA may be mediated in part by restoring the gut microbiota, which intermediate processes involve circulating endotoxins and inflammatory mediators, SNpc oxidative stress and lipid peroxidation. The gut-microbiome - brain axis may be a potential mechanism of EA treatment for the PD.

Alleviation of allergic asthma by rosmarinic acid via gut-lung axis

BackgroundAsthma affects 3% of the global population, leading to over 0.25 million deaths. Due to its complexity, asthma is difficult to cure or prevent, and current therapies have limitations. This has led to a growing demand for alternative asthma treatments. We found rosmarinic acid (RosA) as a potential new drug candidate from natural medicine. However, RosA has poor bioavailability and remains mainly in the gastrointestinal tract after oral administration, suggesting the involvement of gut microbiota in its bioactivity. PurposeTo investigate the mechanism of RosA in alleviating allergic asthma by gut-lung axis. MethodsWe used 16S rRNA gene sequencing and metabolites analysis to investigate RosA's modulation of gut microbiota. Techniques of molecular biology and metabolomics were employed to study the pharmacological mechanism of RosA. Cohousing was used to confirm the involvement of gut microbiota in RosA-induced improvement of allergic asthma. ResultsRosA decreased cholate levels from spore-forming bacteria, leading to reduced 5-hydroxytryptamine (5-HT) synthesis, bronchoconstriction, vasodilation, and inflammatory cell infiltration. It also increased short-chain fatty acids (SCFAs) levels, facilitating the expression of intestinal tight junction proteins to promote intestinal integrity. SCFAs upregulated intestinal monocarboxylate transporters (MCTs), thereby improving their systemic delivery to reduce Th2/ILC2 mediated inflammatory response and suppress eosinophil influx and mucus production in lung. Additionally, RosA inhibited lipopolysaccharide (LPS) production and translocation, leading to reduced TLR4-NFκB mediated pulmonary inflammation and oxidative stress. ConclusionsThe anti-asthmatic mechanism of oral RosA is primarily driven by modulation of gut microbiota-derived 5-HT, SCFAs, and LPS, achieving a combined synergistic effect. RosA is a safe, effective, and reliable drug candidate that could potentially replace glucocorticoids for asthma treatment.

Nesterenkonia marinintestina sp. nov., isolated from the fish intestine.

A Gram-positive, aerobic, non-motile, irregular short rod, nonspore-forming actinobacterial strain, designated GX14115T, was isolated from fish intestine in Beihai City, Guangxi, China and subjected to a taxonomic polyphasic investigation. Colonies were yellow‒green, circular, smooth, central bulge, convex, opaque and 2.0-3.0mm in diameter after growth on 2216E medium at 30°C for 72h. Growth occurred at 4-45°C (optimum 30°C), at pH 4.5-10.0 (optimum pH 7.5) and in the presence of 0-12% NaCl (w/v) (optimum 3.5%). Chemotaxonomic analysis showed that the main menaquinone of strain GX14115T was MK-7. The major cellular fatty acids were anteiso-C15:0 (44.8%), anteiso-C17:0 (20.5%), and iso-C15:0 (16%). The whole-cell sugars were galactose and xylose. The peptidoglycan type was L-Lys-Gly-D-Asp, and the polar lipids were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), one unknown phospholipid (UP), and one unknown glycolipid (UG). The DNA G + C content of the type of strain was 69.5mol%. The 16S rRNA gene sequence analysis revealed that strain GX14115T is affiliated with the genus Nesterenkonia and is closely related to Nesterenkonia sandarakina YIM 70009T (96.5%) and Nesterenkonia lutea YIM 70081T (96.8%). The calculated results indicated that the average nucleotide identity (ANI) values of GX14115T were 74.49-74.78%, to the two aforementioned type strains, and the digital DNA-DNA hybridization (dDDH) values were 20.1-20.7%. Strain GX14115T was proposed as a novel species of the genus Nesterenkonia by the physiological, chemotaxonomic, and phylogenetic data, for whose the name is Nesterenkonia marinintestina sp. nov. The type of strain is GX14115T (= MCCC 1K06658T = KCTC 49495T).

Combined exposure with microplastics increases the toxic effects of PFOS and its alternative F-53B in adult zebrafish

Microplastics (MPs) can adsorb and desorb organic pollutants, which may alter their biotoxicities. Although the toxicity of perfluorooctane sulfonate (PFOS) and its alternative 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) to organisms has been reported, the comparative study of their combined toxic effects with MPs on aquatic organisms is limited. In this study, adult female zebrafish were exposed to 10 μg/L PFOS/F-53B and 50 μg/L MPs alone or in combination for 14 days to investigate their single and combined toxicities. The results showed that the presence of MPs reduced the concentration of freely dissolved PFOS and F-53B in the exposure solution but did not affect their bioaccumulation in the zebrafish liver and gut. The combined exposure to PFOS and MPs had the greatest impact on liver oxidative stress, immunoinflammatory, and energy metabolism disorders. 16S rRNA gene sequencing analysis revealed that the combined exposure to F-53B and MPs had the greatest impact on gut microbiota. Functional enrichment analysis predicted that the alternations in the gut microbiome could interfere with signaling pathways related to immune and energy metabolic processes. Moreover, significant correlations were observed between changes in gut microbiota and immune and energy metabolism indicators, highlighting the role of gut microbiota in host health. Together, our findings demonstrate that combined exposure to PFOS/F-53B and MPs exacerbates liver immunotoxicity and disturbances in energy metabolism in adult zebrafish compared to single exposure, potentially through dysregulation of gut microbiota.