Otus scops adenovirus: the complete genome sequence of a novel aviadenovirus discovered in a wild owl.

We present the complete genome sequence of an aviadenovirus obtained by metagenomics from cloacal swabs taken from a free-living Eurasian scops owl (Otus scops, a small raptor distributed in Europe and several parts of Asia) in China. Thirty protein coding genes were predicted in this 40,239-bp-long genome, which encodes the largest fiber protein among all reported aviadenoviruses. The viral genome sequence is highly divergent, and the encoded proteins have an average of only 55% amino acid sequence identity to those of other adenoviruses. In phylogenetic analysis, the new owl virus grouped with members of the genus Aviadenovirus and formed a common clade with another owl adenovirus reported previously in Japan. This is the second complete genome sequence of an aviadenovirus discovered in owls, and its proteins have an average of 62% amino acid sequence identity to those of the previously reported owl adenovirus. Combining this result with comparative genomic analysis of all aviadenoviruses, we propose that this owl virus and the previously described Japanese owl adenovirus can be assigned to two new species in the genus Aviadenovirus. This study provides new data on the diversity of aviadenoviruses in wild birds.

The Structure and Function of Microbial Community in Rhizospheric Soil of American Ginseng (Panax quinquefolius L.) Changed with Planting Years.

The changes of microbial communities of rhizospheric soil in different ages are speculated to cause soil-borne diseases and replanting problem in American ginseng (Panax quinquefolius L.) cultivation. This study analyzed the physicochemical properties and microbial communities of rhizospheric soil during the planting of American ginseng in the Wendeng area of Weihai, China. The water content and organic matter content of American ginseng rhizospheric soil decreased year by year. A decline in the diversity of bacteria and fungi was observed in the rhizospheric soils planting American ginseng compared with the traditional crop wheat in the control group. During the later planting stage, the abundances of Proteobacteria, Actinobacteria, and Basidiomycota were lower, whereas that of Acidobacteria, Firmicutes, and Mucoromycota were higher. Through the correlation analysis between environmental factors and microbial community, it was found that the content of soil phosphorus was significantly positively correlated with the root rot pathogen Fusarium. The results of functional prediction showed that the decrease of secondary metabolite synthesis of rhizospheric soil bacteria and the increase of plant pathogenic fungi may be the important reasons for the increase of diseases in the later stage of American ginseng planting. This study revealed the evolution of rhizosphere microbial community and function in the process of American ginseng planting, which is valuable for planting management.

Black Soldier Fly (Hermetia illucens) Larvae Significantly Change the Microbial Community in Chicken Manure.

Using black soldier fly (Hermetia illucens) larvae in treatment of livestock manure is a promising technology. In this study, high-throughput sequencing was used to analyze the microbial community in chicken manure before and after treatment with H. illucens larvae. In fresh chicken manure, the most abundant bacterial phylum was Firmicutes (55.58%) followed by Bacteroidetes (24.52%) and then Proteobacteria (12.29%). After treatment of the manure with H. illucens larvae for 15 days, the abundance of Firmicutes increased to 97.72% while that of Bacteroidetes and Proteobacteria decreased. Concomitantly, the most abundant genera of fungi in chicken manure changed from Kernia (46.19%) and Microascus (17.22%) to Penicillium (46.82%) and Aspergillus (45.22%). Correlation-network analysis showed the existence of strong and complex correlations between the dominant operational taxonomic units (OUT) of bacteria and fungi. While most of these correlations were positive, three specific genera, namely g_norank_f_Bacillaceae, Penicillium, and Aspergillus exhibited negative correlations with the remaining genera. These three genera were highly abundant in the intestines of H. illucens and in chicken manure treated with H. illucens larvae. Based on 16S rDNA microbiome-function predictions, the metabolic pathways associated with sugars, amino acids, and organic pollutants inside the intestinal tract of H. illucens were enriched versus those of the other three groups. In summary, the treatment of chicken manure with H. illucens larvae significantly reduced the microbial diversity, while strongly increasing organic metabolism in the intestinal bacteria. This technology shows the potential for applications in livestock manure treatment.

Cytotoxic Secondary Metabolites Isolated from the Marine Alga-Associated Fungus Penicillium chrysogenum LD-201810.

A new pentaketide derivative, penilactonol A (1), and two new hydroxyphenylacetic acid derivatives, (2'R)-stachyline B (2) and (2'R)-westerdijkin A (3), together with five known metabolites, bisabolane-type sesquiterpenoids 4-6 and meroterpenoids 7 and 8, were isolated from the solid culture of a marine alga-associated fungus Penicillium chrysogenum LD-201810. Their structures were elucidated based on extensive spectroscopic analyses, including 1D/2D NMR and high resolution electrospray ionization mass spectra (HRESIMS). The absolute configurations of the stereogenic carbons in 1 were determined by the (Mo2(OAc)4)-induced circular dichroism (CD) and comparison of the calculated and experimental electronic circular dichroism (ECD) spectra, while the absolute configuration of the stereogenic carbon in 2 was established using single-crystal X-ray diffraction analysis. Compounds 2 and 3 adapt the 2'R-configuration as compared to known hydroxyphenylacetic acid-derived and O-prenylated natural products. The cytotoxicity of 1-8 against human carcinoma cell lines (A549, BT-549, HeLa, HepG2, MCF-7, and THP-1) was evaluated. Compound 3 exhibited cytotoxicity to the HepG2 cell line with an IC50 value of 22.0 µM. Furthermore, 5 showed considerable activities against A549 and THP-1 cell lines with IC50 values of 21.2 and 18.2 µM, respectively.

Characterization and Complete Genome Analysis of the Carbazomycin B-Producing Strain Streptomyces luteoverticillatus SZJ61.

Members of marine Actinobacteria have been highly regarded as potentially important sources of antimicrobial compounds. Here, we isolated a strain of Actinobacteria, SZJ61, and showed that it inhibits the in vitro growth of fungi pathogenic to plants. This new isolate was identified as Streptomyces luteoverticillatus by morphological, biochemical and genetic analyses. Antifungal compounds were isolated from S. luteoverticillatus strain SZJ61 and characterized as carbazomycin B by nuclear magnetic resonance spectra. We then sequenced the genome of the S. luteoverticillatus SZJ61 strain, which consists of only one 7,367,863 bp linear chromosome that has a G+C content of 72.05%. Thirty-five putative biosynthetic gene clusters for secondary metabolites, including a variety of bioactive products, were found. Mining of the genome sequence information revealed the putative biosynthetic gene cluster of carbazomycin B. This genomic information is valuable for interpreting the biosynthetic mechanisms of diverse bioactive compounds that have potential applications in the pharmaceutical industry.

Antineoplastic Constituents from the Chemical Diversified Extract of Radix puerariae.

To enhance the structural diversity of isoflavonoids and provide more derivatives for the biological screening, a semisynthetic mixture was generated by diversification of the crude extract of Radix puerariae (Pueraria montana var. lobata) through the chemical reaction with hydrazine hydrate. Eleven 3,4-diarylpyrazoles (1-11) and two 5-phenyl-6-benzyldihydropyridazinones (12 and 13) were isolated from the semisynthetic mixture, and their structures were identified by spectroscopic methods in combination with X-ray crystallographic analysis. Among them, nine compounds (5-13) were new derivatives. All the compounds were evaluated on the inhibitory activities against the prostate cancer cell lines LNCaP and PC3. Compounds 12 and 13 were found to exhibit much more potent inhibitory activities against the androgen dependent LNCaP cells than the androgen independent PC3 cells. Rapid synthesis of new 3,4-diarylpyrazoles and two 5-phenyl-6-benzyldihydropyridazinones with significant biological activity highlights the great potential of one-pot combinatorial modification for the diversification of natural products.

Antimicrobial Secondary Metabolites from the Seawater-Derived Fungus Aspergillus sydowii SW9.

Marine-derived fungi are considered to be valuable producers of bioactive secondary metabolites used as lead compounds with medicinal importance. In this study, chemical investigation of the seawater-derived fungus Aspergillus sydowii SW9 led to the isolation and identification of one new quinazolinone alkaloid, 2-(4-hydroxybenzyl)-4-(3-acetyl)quinazolin-one (1), one new aromatic bisabolene-type sesquiterpenoid, (2) and one new chorismic acid analogue (3), as well as two known alkaloids (compounds 4 and 5). Their structures were determined by extensive 1D/2D NMR and mass spectrometric data, and the absolute configurations of 2 and 3 were assigned by the analysis of ECD spectra aided by quantum chemical computations. Compounds 1, 2, and 4 exhibited selective inhibitory activities against the human pathogenic bacteria Escherichia coli, Staphylococcus aureus, S. epidermidis, and Streptococcus pneumoniae, with MIC values ranging from 2.0 to 16 µg/mL.

Caprine herpesvirus 2-associated malignant catarrhal fever of captive sika deer (Cervus nippon) in an intensive management system.

BACKGROUND: Caprine herpesvirus 2 (CpHV-2) infection usually induces chronic malignant catarrhal fever (MCF) in sika deer (Cervus nippon), with the primary signs of weight loss, dermatitis and alopecia. CASE PRESENTATION: Here, we report a case of CpHV-2-associated acute MCF in a sika deer herd raised in an intensive management system distant to the reservoir goats. Affected deer developed clinical signs of high fever (41 °C) followed by nasal discharge and lameness. Severe lesions of hemorrhage, necrosis and infiltration of lymphoid cells could readily be observed in the lung, kidney, heart valves and subcutaneous tissue surrounding a tendon. Etiologically, identical CpHV-2 specific DNA sequences were detected in peripheral blood lymphocyte (PBL) from the affected deer and reservoir goats. CONCLUSION: In summary, domestic goats were the reservoir of the CpHV-2, which is the causative agent of the outbreak of MCF in the three hinds. The disease was probably transmitted via aerosol infection. In addition, necrosis and inflammation in subcutaneous tissue surrounding a tendon was the reason for lameness. Therefore, MCF should be put into a differential diagnostic list when similar disease occurs in sika deer herds.

Genome analysis of a novel avian atadenovirus reveals a possible horizontal gene transfer.

We report the discovery and characterization of a novel adenovirus, Zoothera dauma adenovirus (ZdAdV), from a wild bird species, Zoothera dauma (Scaly thrush). This new atadenovirus was discovered by metagenomic sequencing without virus cultivation. Analyses of the full genome sequence revealed that this new virus is a distinct member of the genus Atadenovirus and represents a novel species. ZdAdV has a genome of 34,760 bp with 28 predicted genes and 39% GC content. ZdAdV is the first atadenovirus to contain ORF19, a gene previously found only in aviadenoviruses. Phylogenetic analysis of ORF19 suggests that it was acquired by ZdAdV through horizontal gene transfer from an aviadenovirus. By analyzing all orthologous genes of aviadenovirus, mastadenovirus, atadenovirus, and siadenovirus, we also found potential horizontal gene transfer for the E4 gene in Pigeon aviadenovirus B. Our study widens our knowledge concerning the genetic diversity and evolutionary history of atadenoviruses and their potential for cross-species transmission.

China-origin G1 group isolate FPV072 exhibits higher infectivity and pathogenicity than G2 group isolate FPV027.

Introduction: Feline parvovirus (FPV), a single-stranded DNA virus, is accountable for causing feline panleukopenia, a highly contagious and often lethal disease that primarily affects cats. The epidemiology prevalence and pathogenicity of FPV in certain regions of China, however, remains unclear. The aim of this research was to investigate the epidemiology of FPV in different regions of China in 2021 and compare its infectivity and pathogenicity. Methods: In this research, a total of 36 FPV strains were obtained from diverse regions across China. Phylogenetic analysis was performed based on the VP2 and NS1 sequences, and two representative strains, FPV027 and FPV072, which belonged to different branches, were selected for comparative assessment of infectivity and pathogenicity. Results and discussion: The results revealed that all strains were phylogenetically classified into two groups, G1 and G2, with a higher prevalence of G1 strains in China. Both in vitro and in vivo experiments demonstrated that FPV072 (G1 group) exhibited enhanced infectivity and pathogenicity compared to FPV027 (G2 Group). The structural alignment of the VP2 protein between the two viruses revealed mutations in residues 91, 232, and 300 that may contribute to differences in infectivity and pathogenicity. The findings from these observations will contribute significantly to the overall understanding of the molecular epidemiology of FPV in China and facilitate the development of an effective FPV vaccine.

Construction of an inhalable recombinant M2e-FP-expressing Bacillus subtilis spores-based vaccine and evaluation of its protection efficacy against influenza in a mouse model.

Influenza A virus (IAV) is a deadly zoonotic pathogen that remains a burden to global health systems despite continuous vaccinations, indicating the need for an improved vaccine strategy. In this work, we constructed a new recombinant influenza vaccine using Bacillus subtilis spores expressing M2e-FP protein (RSM2eFP) and assessed its potency and efficacy in BALB/c mouse immunized via aerosolized intratracheal inoculation (i.t.) or intragastric (i.g.) administration. Immunization via i.t. route conferred 100 % protection against 20 × LD50 A/PR/8/34 (H1N1) virus compared with only 50 % via the i.g. route. Even when challenged with 40 × LD50 virus, the RSM2eFP vaccine immunized via i.t. provided 80 % protection. Consistently, i.t. inoculation of RSM2eFP spore vaccine induced a stronger lung mucosal immune response and a greater cellular immune response than i.g. administration, as indicated by the high production of IgG and SIgA. In addition, the RSM2eFP spore vaccine diminished the yield of infectious virus in the lung of mice immunized via i.t. These results suggest that i.t. immunization of the RSM2eFP spore vaccine may be a promising strategy for the development of mucosal vaccines against IAV infections.

Spatial distribution of airborne bacterial communities in caged poultry houses.

Microbial aerosols in intensive broiler houses whose species and concentrations are closely related to human health are ubiquitous. Based on 16S rRNA gene sequencing, the aim of this study was to investigate the spatial distribution and diversity of bacterial aerosols in the air of broiler houses. Significant spatial variations in airborne bacterial concentrations were observed inside the poultry farmhouse. The results indicated that bacteria in the air samples could be grouped into a total of 1,674 OTUs. Alpha diversity analysis showed that the diversity of the microbial community at the entry of the broiler house was higher than that at the middle or the rear (p < 0.01). The Sankey diagram illustrated species dynamic changes in Proteobacteria, Firmicutes, and Actinobacteria among the different locations. From the aspect of LEfSe (LDA Effect Size) analysis, we discovered that the abundance of Planctomycetes was significantly higher in the entry than in the rear and middle. This study shows the spatial distribution of the entire bacterial community in intensive broiler houses, which offers a new perspective for studying airborne total bacteria in those environments.Implications: The bacteria contained in air aerosols from poultry houses are closely connected to animal health and production. This study aimed to investigate the spatial distribution and diversity of bacterial aerosols in the air of broiler houses. The results observed that bacterial aerosol concentrations in the examined broilers house varied greatly at different positions, and a significantly higher exposure to bacterial aerosol was observed at the middle than at the other positions (p < 0.05). The alpha diversity analysis showed that the diversity of the microbial community at the entry of the broiler house was higher than that at the middle or the rear (P<0.01). Sankey diagram illustrated species dynamic changes of Proteobacteria, Firmicutes and Actinobacteria among the different locations. The microbial communities in genus level in the samples of entry and rear were closer, while the species diversity of middle and rear samples in chicken house was highly similar (P>0.05). Altogether, results revealed that the effects of spatial factors on the diversity and abundance of bacteria in the air of closed-cage broiler houses, which poses a potential threat to the health of animals and workers in those environments.

Feed nutritional composition affects the intestinal microbiota and digestive enzyme activity of black soldier fly larvae.

Introduction: Using black soldier fly larvae (BSFLs) to treat food waste is one of the most promising environmental protection technologies. Methods: We used high-throughput sequencing to study the effects of different nutritional compositions on the intestinal microbiota and digestive enzymes of BSF. Results: Compared with standard feed (CK), high-protein feed (CAS), high-fat feed (OIL) and high-starch feed (STA) had different effects on the BSF intestinal microbiota. CAS significantly reduced the bacterial and fungal diversity in the BSF intestinal tract. At the genus level, CAS, OIL and STA decreased the Enterococcus abundance compared with CK, CAS increased the Lysinibacillus abundance, and OIL increased the Klebsiella, Acinetobacter and Bacillus abundances. Diutina, Issatchenkia and Candida were the dominant fungal genera in the BSFL gut. The relative abundance of Diutina in the CAS group was the highest, and that of Issatchenkia and Candida in the OIL group increased, while STA decreased the abundance of Diutina and increased that of Issatchenkia. The digestive enzyme activities differed among the four groups. The α-amylase, pepsin and lipase activities in the CK group were the highest, and those in the CAS group were the lowest or the second lowest. Correlation analysis of environmental factors showed a significant correlation between the intestinal microbiota composition and digestive enzyme activity, especially α-amylase activity, which was highly correlated with bacteria and fungi with high relative abundances. Moreover, the mortality rate of the CAS group was the highest, and that of the OIL group was the lowest. Discussion: In summary, different nutritional compositions significantly affected the community structure of bacteria and fungi in the BSFL intestinal tract, affected digestive enzyme activity, and ultimately affected larval mortality. The high oil diet gave the best results in terms of growth, survival and intestinal microbiota diversity, although the digestive enzymes activities were not the highest.

Identification of Mudanjiang Phlebovirus in the Daxing'anling Region of China.

Mudanjiang phlebovirus (MJPV) is a newly discovered phlebovirus, initially detected from Ixodes persulcatus ticks in China in 2022. In this study, by next-generation sequencing (NGS) on a wide variety of ticks and wild small animals in China, we detected MJPV from I. persulcatus and Meriones meridianus. Additionally, we conducted RT-PCR and sequencing on 1815 adult ticks and 805 wild small mammals collected from eight provinces in China between 2017 and 2021. MJPV RNA-positive results were found in 0.22% (4/1815) of tick samples, as well as in 0.12% (1/805) of rodent samples. All positive detections were obtained from Heilongjiang and Inner Mongolia. Sequencing analysis revealed nucleotide similarities ranging from 98.23% to 99.11%, as well as amino acid similarities ranging from 99.12% to100%, between the current MJPV strain and previously reported strains of MJPV. Phylogenetic tree analysis demonstrated that the previously reported MJPV strain along with our two variants clustered together with other tick-borne phenuiviruses, indicating their close relationship within this viral group. This study represents the first detection of MJPV infection in wild rodents, expanding the known host range for this virus in the endemic regions.

Extracellular vesicle-mediated regulation of macrophage polarization in bacterial infections.

Extracellular vesicles (EVs) are nanoscale membrane-enveloped vesicles secreted by prokaryotic and eukaryotic cells, which are commonly defined as membrane vesicles (MVs) and exosomes, respectively. They play critical roles in the bacteria-bacteria and bacteria-host interactions. In infectious diseases caused by bacteria, as the first line of defense against pathogens, the macrophage polarization mode commonly determines the success or failure of the host's response to pathogen aggression. M1-type macrophages secrete pro-inflammatory factors that support microbicidal activity, while alternative M2-type macrophages secrete anti-inflammatory factors that perform an antimicrobial immune response but partially allow pathogens to replicate and survive intracellularly. Membrane vesicles (MVs) released from bacteria as a distinctive secretion system can carry various components, including bacterial effectors, nucleic acids, or lipids to modulate macrophage polarization in host-pathogen interaction. Similar to MVs, bacteria-infected macrophages can secrete exosomes containing a variety of components to manipulate the phenotypic polarization of "bystander" macrophages nearby or long distance to differentiate into type M1 or M2 to regulate the course of inflammation. Exosomes can also repair tissue damage associated with the infection by upregulating the levels of anti-inflammatory factors, downregulating the pro-inflammatory factors, and regulating cellular biological behaviors. The study of the mechanisms by which EVs modulate macrophage polarization has opened new frontiers in delineating the molecular machinery involved in bacterial pathogenesis and challenges in providing new strategies for diagnosis and therapy.

Spatial and Temporal Persistence of Fluorescent Lactiplantibacillus plantarum RS-09 in Intestinal Tract.

The beneficial effects of the probiotic strain Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) are based on its adherence and colonization ability in the gut. However, little is known about the migration and long-term gut colonization of the strain. This study evaluated the gut colonization modes of Lactiplantibacillus plantarum RS-09 to identify the strain with long-term gut colonization potential. We established CFDA/SE-labeled RS-09 to study the temporal and spatial distribution of RS-09 in the intestine as well as to analyze its persistence in different parts of the intestine by flow cytometry. This study has shown that the RS-09 strain maintains strong adhesion abilities under acid (pH 2.5) and base (pH 8.5) conditions. In addition, CFDA/SE can be used as an indicator for the labeling of L. plantarum RS-09 in the intestinal tract in vivo. We established a growth kinetics model of RS-09 to elucidate its persistence in the intestine. In vivo persistence experiments showed that the persistence rate of RS-09 was the highest in the cecum (69.5%) and the lowest in the duodenum (12.8%) at 96 h. After 20 days, RS-09 was predominantly localized in the cecum and colon steadily. These studies provide new insights into the long-term persistence of L. plantarum in the gastrointestinal tract. The CFDA/SE label system may be used to study the in vivo colonization dynamics of other probiotic strains.

Whole genome analysis of a novel adenovirus discovered from Oriolus chinesis.

We present the first complete genome sequence of an aviadenovirus Oriolus adenovirus (OrAdV) sequenced from the cloaca of a Oriolus chinensis (a passerine bird widely distributed in Asia), which was collected from an island off the east coast of China. Thirty-one protein coding genes were predicted in this 40425-bp-long genome. OrAdV genome is highly divergent and has only 57% average protein identity compared with other aviadenovirus genomes. Comparative genomic analysis indicates that this passerine virus is a new species of aviadenovirus. One unique thymidylate kinase gene was discovered in OrAdV genome. This gene is absent in other adenovirus genomes and usually reported to occur in herpesvirus. Protein sequence alignment against all known proteins indicates that this gene may be originated from ancient horizontal gene transfer event between virus and parasitic eukaryote like protozoan. This new aviadenovirus genome enriches the genomic information of adenovirus and suggests that there is a large unknown space of adenovirus world.

PM2.5 Synergizes With Pseudomonas aeruginosa to Suppress Alveolar Macrophage Function in Mice Through the mTOR Pathway.

High concentrations of PM2.5 in enclosed broiler houses cause respiratory disorders in humans and animals. Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that can induce severe respiratory disease in animals under stress or with abnormal immune functions. Alveolar macrophages are lung-resident immune cells that play important roles in lung host defence and immune balance. In this study, the mechanism by which PM2.5 synergizes with P. aeruginosa to damage alveolar macrophage function and induce inflammation was investigated. The results will provide a theoretical basis for improving the poultry breeding environment and preventing the recurrence of infection with P. aeruginosa. Alveolar macrophages were stimulated by PM2.5 collected in an enclosed broiler house and P. aeruginosa. Phagocytosis was determined by the neutral red test. The apoptosis rate and cytoskeleton changes were observed by flow cytometry assays and laser scanning confocal microscopy. Protein levels related to autophagy and the mTOR pathway were detected by Western blotting. The results indicated that PM2.5 in combination with P. aeruginosa could decrease phagocytosis, inhibit autophagy, increase apoptosis, and destroy the cytoskeleton in alveolar macrophages. In addition, alveolar macrophages had significantly increased expression of mTOR pathway-related proteins in response to the synergistic stimulation of PM2.5 and P. aeruginosa. The above results confirmed that PM2.5 in poultry houses synergized with P. aeruginosa to impede alveolar macrophage function and caused more severe respiratory system injuries through a process closely related to the activation of the mTOR signalling pathway.

Lactobacillus plantarum RS-09 Induces M1-Type Macrophage Immunity Against Salmonella Typhimurium Challenge via the TLR2/NF-κB Signalling Pathway.

Lactobacillus plantarum can interact with macrophages against bacterial enteropathy due to its potential ability to modulate macrophage polarization. However, this mechanism is not completely understood. TLR2 can recognize microbial components and trigger macrophage cytokine responses to different gram-positive strains. The aim of this study was to investigate whether probiotic Lactobacillus plantarum RS-09 can induce macrophage polarization against Salmonella Typhimurium infection via TLR2 signalling. BALB/c mice were preadministered RS-09 continuously for 7 days and then infected with Salmonella Typhimurium ATCC14028. Mouse RAW264.7 mononuclear macrophages were stimulated with RS-09 and coincubated with ATCC14028 or PBS controls. The results of the in vivo study indicated that RS-09 could relieve S. Typhimurium-induced splenomegaly, body weight loss and death rate. RS-09 also limited the colonization and translocation of S. Typhimurium in the gastrointestinal tract and thereby protected against infection. We also observed that RS-09 upregulated the production of M1 macrophage characteristics (e.g., CD11c and IL-6) against S. Typhimurium. Furthermore, RS-09 induced the expression of TLR2 in macrophages. In an in vitro study, treatment of RAW264.7 cells with RS-09 either concurrently with or before S. Typhimurium challenge enhanced the secretion of Reactive oxygen species and Nitric oxide. This effect was related to TLR2 and NF-κB activation. Based on these findings, Lactobacillus plantarum RS-09 was shown to modulate M1 macrophage polarization and induce TLR2-linked NF-κB signalling activity in the innate immune response to S. Typhimurium infection.

Seasonal dynamics in bacterial communities of closed-cage broiler houses.

The bacteria contained in air aerosols from poultry houses are closely connected to animal health and production. This study aimed to investigate the seasonal factors on microbial aerosol concentration, particle size and bacterial spectrum composition inside a closed-cage broiler house. Then, 16S rDNA sequencing technology was applied to analyze the characteristics of bacterial abundance and diversity. The results indicated that the concentration of bacterial aerosol in the broiler house varied significantly in different seasons, with a concentration range of 5.87-15.77 × 103 CFU/m3, and the highest and lowest concentrations in the summer and winter, respectively. Microbiological analysis showed that the proportion of Gram-negative bacteria in autumn was significantly higher than that in summer (P < 0.05). In addition, the floral structure of potential pathogenic bacterial genera also differed by season. Escherichia-Shigella, Streptococcus, Acinetobacter, Pseudomonas were identified in the bacterial aerosols. Importantly, the relative abundance of Firmicutes in spring and autumn was much higher. In contrast, the relative abundance of Proteobacteria in spring and autumn was lower than that in summer and winter. Altogether, results revealed the effects of seasonal factors on the diversity and abundance of bacteria and the distribution characteristics of major opportunistic pathogens in the air of closed-cage broiler houses. These results will provide important information for exploring the potential risk of aerosols from poultry houses all four seasons.