Search Results (548)

Doxorubicin is an effective chemotherapeutic agent, but it causes gastrointestinal toxicity that impairs treatment efficacy and quality of life. This study investigated the effects of liraglutide, a GLP-1 analog, on acute doxorubicin-induced gut toxicity in rats. Sixty male Wistar rats were assigned to four groups: Control (C), Doxorubicin (D), Liraglutide (L), and Doxorubicin + Liraglutide (DL). Groups L and DL received liraglutide (0.6 mg/kg, s.c.) for two weeks. D and DL were given a single dose of doxorubicin (20 mg/kg, i.p). After 48 h, the distal colon, feces, and blood were collected. Results: Doxorubicin caused crypt disruption, goblet cell loss, apoptosis, and reduced fecal short-chain fatty acids. Levels of TNF-α, NF-κB, Bcl-2, TLR4, and antioxidant enzymes were unchanged among groups. Microbiota analysis showed similar α-diversity but altered β-diversity. Doxorubicin reduced Bacteroidetes and increased Proteobacteria, with higher Arcanobacterium and Clavibacter genera abundance. Liraglutide alone decreased Bacteroidetes and increased Corynebacterium and Actinobaculum genera. Combined treatment showed no significant effects. We conclude that acute doxorubicin administration induces intestinal structural damage, reduces short-chain fatty acids, and changes microbiota composition. Although liraglutide alters microbial profiles, it does not attenuate doxorubicin-induced gut toxicity. Full article

Kennel-housed dogs may experience chronic stress affecting cognition. This study compared the effects of Lycium barbarum polysaccharides (LBP) and glycopeptide (LbGP) on cognitive function in laboratory-kenneled poodles. Eighteen dogs were assigned to CON, LBP, or LbGP groups for 42 days. Cognitive tests were performed and serum, saliva, and feces were collected for subsequent analysis. Both supplements improved cognitive performance (e.g., increased the correct rate in the cylinder test by approximately 40.0%, both p < 0.001). LBP enriched beneficial bacteria (Faecalibacterium and Bacteroides, p < 0.05), reduced pathogens (Romboutsia and Terrisporobacter, p < 0.05), and predominantly influenced the indole pathway of tryptophan metabolism. LbGP specifically decreased Escherichia-Shigella and Corynebacterium, increased fecal SCFAs, and mainly targeted the 5-HT pathway. Both treatments regulated immune function (i.e., elevated IL-6 and IL-10) and antioxidant capacity; LBP significantly increased serum superoxide dismutase (SOD) levels by 6.8% (p < 0.01) and BDNF levels by 13.5% (p < 0.05), while LbGP elevated (p < 0.01) glutathione peroxidase (GSH-Px) levels by 20.9% and reduced salivary cortisol levels by 14.2% (p < 0.01). Overall, LBP and LbGP support canine cognition through distinct microbiota-related mechanisms, likely via the microbiota–gut–brain axis, suggesting their potential as functional feed additives for cognitive health. Full article

Probiotics are commonly applied to maintain the balance of gut microbiota and regulate the intestinal metabolic function of companion animals. In the present study, complex probiotics (Bacillus coagulans SNZ-1969, Bacillus subtilis, and Bacillus licheniformis) were added into the basal diet of domestic cats to investigate their influence on the intestinal microbiome and metabolic characteristics. Results revealed that the alpha diversity of the gut microbiota in the probiotic group was enhanced when compared to the control group. The beta diversity of the gut microbiota was also altered by the oral consumption of the complex probiotics. Compared to the control group, the relative abundance of beneficial microbes (such as Clostridium, Bacteroides, Phocaeicola, and Ruminococcus) in the probiotic group was enhanced, while the relative abundance of opportunistic pathogens (such as Escherichia, Gallibacter, Corynebacterium) was decreased. Additionally, the intestinal metabolic characteristics of domestic cats were also changed. The metabolomic analysis identified 408 differential metabolites between the two groups, and the KEGG function pathway analysis proved that the dominant pathway related to the differential metabolites were the amino acid metabolism, lipid metabolism, carbohydrate metabolism, energy metabolism, endocrine system, digestive system, immune system, and other metabolic pathways. Spearman’s correlation analysis revealed that the beneficial microbes had positive correlations with the differential metabolites. In conclusion, the current study demonstrated that oral administration of complex probiotics could regulate overall health and well-being in domestic cats through modulating the gut microbiome and metabolic characteristics. Full article

The MarR (multiple antibiotic resistance regulator) family regulators, which are widely conserved across various organisms, play pivotal roles in metabolism, stress response mechanisms, and virulence factor production. However, the regulatory functions of these factors in the degradation of aromatic compounds within Corynebacterium glutamicum remain largely uncharacterized. In this study, we identified a MarR-type regulator, designated AcsR (encoded by ncgl2425), which directly represses the expression of the catechol 2,3-dioxygenase gene ncgl2007 (c23o) and the heavy metal (nickel) transport system permease gene ncgl2351, while activating the expression of ncgl2258 encoding an ABC-type C4-dicarboxylate-binding periplasmic protein. AcsR binds specifically as a dimer to a 6 bp inverted repeat sequence, and this binding is disrupted by catechol in vitro. Correspondingly, catechol induces the expression of c23o in vivo. Phenotypic analysis revealed that the ΔacsR mutant exhibited enhanced resistance to multiple aromatic compounds but increased sensitivity to antibiotics, heavy metals, and oxidants. Collectively, these findings demonstrate that AcsR is an important regulator of stress adaptation in C. glutamicum and provide new insights into the regulatory mechanisms of aromatic compound degradation in this industrially important bacterium. Full article

C. pseudotuberculosis is a Gram-positive pathogenic bacterium that infects various animals, causing diseases such as caseous lymphadenitis, leading to significant economic losses in the livestock industry and posing zoonotic risks. This study targeted the conserved gyrA gene fragment of this bacterium, designed specific primers, optimized the reaction system and conditions, and established a high-resolution melting curve (HRM) detection method with potential utility for preliminary molecular screening. Validation showed that this method exhibits strong specificity, producing specific amplification only for the target biovars. The melting temperatures (Tm values) for the two biovars were 86.16 ± 0.05 °C and 86.92 ± 0.05 °C, respectively, allowing clear differentiation. It demonstrated high sensitivity, with minimum detection limits of 28 copies/μL and 25 copies/μL for standard plasmids of the ovis and equi biovars, respectively. The method also showed good reproducibility, with intra- and inter-batch coefficients of variation both below 1.0%. Applied to 133 clinical nasal swab samples from goats in Fujian Province, the method detected a positivity rate of 19.5% and indicates that a biovar equi-like gene fragment was detected in goat nasal swabs from Fujian Province via molecular screening. The HRM method developed in this study is sensitive, specific, simple, and cost-effective, enabling rapid detection and biovar differentiation of C. pseudotuberculosis. It is suitable for large-scale clinical sample screening and provides an efficient technical approach for epidemiological monitoring and precise control of the disease. Full article

Background and objectives: Occupational and environmental inhalation exposures, including high-aspect-ratio carbon nanotubes, can trigger pulmonary fibrosis (PF). The relationship between exposure-specific fibrogenic pathways (granulomatous inflammation versus diffuse epithelial injury) and lung microbiome dysbiosis remains incompletely understood. We therefore compared lung microbiome alterations in rat PF models induced by multi-walled carbon nanotubes (MWCNTs) and bleomycin. Materials and Methods: Female Wistar rats received a single intratracheal instillation of vehicle, MWCNTs (750 μg/rat), or bleomycin (1 mg/rat). At day 28, fibrosis and inflammation were evaluated by histopathology and bronchoalveolar lavage fluid (BALF) profiling. Lung microbial communities were characterized by 16S rRNA gene sequencing (V3–V4). Seventeen lung samples passed stringent quality control and were analyzed (control n = 5; bleomycin n = 7; MWCNT n = 5). Results: Both agents induced PF with increased profibrotic signaling, but with distinct pathological signatures: MWCNTs produced localized granulomatous lesions and a robust neutrophilic response (25% of BALF cells), whereas bleomycin caused diffuse interstitial remodeling. Bleomycin increased microbial richness (alpha diversity; p < 0.05) and significantly shifted community structure (beta diversity; p < 0.05), while MWCNT exposure showed comparatively limited changes in global diversity. The relative abundance of Pseudogracilibacillus (including P. marinus) was higher in the bleomycin group than in controls, whereas Facklamia tabacinasalis and Corynebacterium maris were more abundant in the MWCNT group. Across samples, Proteobacteria abundance was inversely correlated with BALF TGF-β, MCP-1, and neutrophil proportion. At the species level, Pseudogracilibacillus marinus was positively correlated with BALF TGF-β, while Facklamia tabacinasalis and Corynebacterium maris were positively correlated with MCP-1, CINC-3, and neutrophil proportion (Spearman; p < 0.05). Conclusions: Mechanistically distinct fibrogenic exposures generate exposure-linked lung microbiome signatures that track with host inflammatory and profibrotic responses. These signatures may support biomarker development for environmentally and occupationally relevant PF and motivate longitudinal and functional studies to clarify causality. Full article

Corynebacterium lactis was isolated from the skin abscess of a companion dog and from raw milk of a cow with unspecific mastitis. As information about the species was scarce and a zoonotic potential could not be excluded, we started a basic characterization of C. lactis strain RW3-42 with respect to antibiotic susceptibility and the response of invertebrate animal model systems to infection. C. lactis showed a number of antimicrobial resistances and is able to colonize Caenorhabditis elegans. In contrast, Galleria mellonella larvae were not impaired by C. lactis. Genome analyses of strain RW2-5 revealed the absence of toxin-encoding genes, and only a rather small number of other virulence factors were found, i.e., SpaA- and SpaH-type pili and the non-fimbrial adhesins DIP0733, DIP1281, DIP1621 and EmbC in addition to a homologue of Salmonella RhuM involved in killing of C. elegans. The results obtained indicate a limited pathogenic potential of the species. Full article

The expansion of tropical specialty livestock farming raises urgent concerns about airborne pathogen and antibiotic resistance dissemination. Ostrich farming, characterized by high-density stocking and feed exposure, yet their microbial ecology remain poorly characterized. This study analyzed 48 bioaerosols samples from an ostrich farm in Hainan, China, across dry and rainy seasons using 16S rRNA sequencing and metagenomics. The bacterial community were dominated by Firmicutes, Proteobacteria, and Actinobacteria, followed by Staphylococcus, Bacillus, and Acinetobacter as predominant genera, with particle size significantly shaping their structure. Large particles (>7.0 μm) carried higher species richness, while medium particles (2.1–3.3 μm) exhibited the highest diversity and evenness. Notably, small particles (0.65–1.1 μm), which can penetrate deep into the lungs, were enriched with Brevibacillus and Corynebacterium. Metagenomic analysis identified 638 antibiotic resistance genes (ARGs), dominated by efflux pump-associated determinants. The detection of clinically relevant ARGs (e.g., mcr-1 and bla_TEM) reflects the genetic potential of the airborne resistome, rather than confirmed resistance phenotypes or active horizontal gene transfer. Functional analysis revealed a strong potential for organic matter degradation, driven by abundant carbohydrate-active enzymes (CAZymes) and their corresponding CAZyme genes, as well as a nitrogen cycle dominated by assimilation and reduction pathways, while genes for nitrogen fixation and nitrification were absent. Our findings demonstrate that ostrich farming enhanced airborne microbial diversity and functional potential, facilitating the ARG dissemination and nitrogen transformation. This study provides critical insights into the ecological and health risks of bioaerosols in tropical livestock farms, informing environmental monitoring and risk management strategies. Full article

(1) Background: Mammographic breast density (MBD) is a well-established predictor of breast cancer risk, yet the biological mechanisms underlying this association remain incompletely understood. MBD is characterized by alterations in breast stromal architecture, including increased collagen deposition and changes in immune cell composition. Given emerging evidence that the breast harbors a resident microbiome, we investigated whether the breast tissue microbiome correlates with MBD. (2) Methods: Adjacent normal breast tissue was collected under sterile conditions from 33 women undergoing surgery for benign or malignant breast disease. DNA was extracted and subjected to 16S rRNA gene sequencing (Illumina MiSeq). (3) Results: We observed a non-significant trend toward lower α-diversity in high-MBD samples compared to low-MBD samples, p = 0.13. β-Diversity analyses identified a modest association between MBD and microbial community composition (MiRKAT p = 0.049). A random forest-based model incorporating genus-level relative abundances improved prediction of MBD over clinical characteristics alone, identifying Corynebacterium (Actinobacteria) and other genera as key predictors. (4) Conclusions: Breast tissue microbial features vary with mammographic breast density, suggesting a potential association with density-associated breast cancer risk. These exploratory findings warrant validation in larger cohorts to better elucidate biological mechanisms and clinical relevance. Full article

Cancer is a major health concern, with its incidence rate continuing to increase. There is growing interest in the microbiota and its role in carcinogenesis, as it significantly influences physiological and pathological processes. Various aspects of the microbiome have been shown to have both anti-tumor and pro-tumor effects. Advances in techniques such as high-throughput DNA sequencing have greatly improved our understanding of microbial populations in the human and canine gut. We aimed to (1) characterize the intestinal microbiota of healthy dogs and dogs with cutaneous mast cell tumors (MCTs), (2) assess changes in the intestinal microbiota of dogs undergoing electrochemotherapy (ECT) combined with gene electrotransfer (GET) of the IL-12 plasmid (IL-12), and (3) explore possible associations with the expression of immune markers Programmed cell death protein 1 (PD-1), Programmed death-ligand 1 (PD-L1), and Granzyme B (GZMB) in MCT tissue. Stool samples were collected from healthy dogs (n = 24) and dogs with MCTs (n = 24) before and after ECT and IL-12 GET. DNA was extracted from the samples, and shallow shotgun sequencing was performed. Immunohistochemistry was performed on the tumors to assess the expression of PD-1, PD-L1, and GZMB. The dysbiosis index, alpha diversity, and beta diversity did not differ between groups. Regarding microbial composition, Bifidobacterium animalis, Corynebacterium variabile, Lactobacillus johnsonii, Pediococcus pentosaceus, Streptococcus anginosus, Streptococcus equinus, Streptococcus intermedius, Clostridium thermobutyricum, Megasphaera elsdenii, and Anaerobiospirillum sp. were found in lower relative abundance in feces of dogs with MCTs, while Bacteroides togonis, Lactobacillus amylolyticus, Prevotella sp. CAG:279, and Megamonas hypermegale were more abundant compared to healthy dogs. Our study provides further insight into the composition of the gut microbiota in dogs with MCTs, where ECT and IL-12 GET did not lead to major shifts. We were unable to establish any association between the expression of immune markers and the microbiota. Full article

Pyridoxal 5′-phosphate (PLP), the active form of vitamin B6, is an essential cofactor, yet its industrial supply still relies largely on multi-step chemical synthesis. Here, using the industrial chassis Corynebacterium glutamicum ATCC 13032, we proposed and validated a strategy based on a minimal heterologous entry coupled to endogenous pathway continuation, resulting in a distinct PLP-producing route. Three engineered strains were constructed and compared: S1 expressing ecepd from Escherichia coli; S2 co-expressing ecepd plus ecpdxB from Escherichia coli (a minimal two-gene module); and S3 carrying an additional ecpdxA from Escherichia coli and smpdxJ from Sinorhizobium meliloti to form a four-gene module as a benchmark for heterologous reconstruction. The wild-type (WT) strain produced a basal PLP level of 10.6 mg/L. Overexpressing ecepd alone increased the titer to 40.4 mg/L (3.8-fold vs WT), whereas the minimal two-gene module in S2 yielded the highest PLP titer of 95.5 mg/L (9.0-fold vs WT; 136.0% higher than S1). Notably, the four-gene module (S3) reached 70.0 mg/L, which was 36.3% lower than S2 under matched conditions. These results indicated that introducing only a minimal two-gene entry could cooperate with the endogenous metabolic network of Corynebacterium glutamicum to establish a new and highly effective PLP biosynthetic route, with production performance exceeding that of a multi-gene heterologous reconstruction in the tested window. This work provides a low-burden and scalable framework for sustainable PLP biomanufacturing and motivates further optimization targeting the endogenous continuation steps and regulatory constraints. Full article

In the past, bacteria detected in the mare’s uterus were generally interpreted as a sign of endometritis, since the uterus was considered a sterile environment. This assumption has been challenged by the introduction of culture-independent molecular techniques, particularly 16S rRNA amplicon sequencing, which have demonstrated that healthy mares harbor an endometrial microbiota. The aim of this study was to characterize the endometrial microbiota of healthy mares and to determine whether microbial composition differs between estrus and diestrus. Endometrial samples were collected from eleven healthy Standardbred mares during estrus and diestrus and analyzed by sequencing the V1–V2 region of the bacterial 16S rRNA gene. A total of 24 bacterial phyla and 599 genera were identified. At the phylum level, Firmicutes, Proteobacteria, Bacteroidota, and Actinobacteriota accounted for most of the relative abundance, while the most abundant genera were Staphylococcus, Acinetobacter, Sphingomonas, Corynebacterium, Streptococcus, Clostridium, and Pseudomonas. Alpha diversity was significantly higher during estrus, likely due to hormonally mediated changes in cervical opening and local immunity. Beta diversity analyses showed substantial overlap between estrus and diestrus samples. The phase of the cycle had a weak effect on microbiota structure, while inter-individual differences between mares explained a larger proportion of the observed variation. These findings suggest that the uterine microbiota of healthy mares is largely stable across the estrous cycle, with phase-dependent and mare-specific fluctuations in microbial composition. Full article

More than 63% of Mexico’s territory is classified as arid or semiarid, where plants belonging to the genus Agave have evolved. Adaptation to drylands resulted from biochemical, physiological, and anatomical properties shared with other crassulacean plants; however, microbial symbionts also play critical roles in plants’ growth, health, and drought tolerance. To explore endophytic communities in Agave plants, we used a shotgun metagenomic approach. The taxonomic and functional diversity of endophytes were studied in the leaves and stem organs of Agave americana, A.angustifolia, A. fourcroydes, A. karwinskii, A. potatorum, A. tequilana, A. cupreata, and A. rodacantha. The microbial community structure did not differ significantly among species, regardless of geographic origin or local environmental conditions, whereas significant differences were observed between organs. We found 4058 genera shared among organs, of which 957 genera are exclusive to the stem and 492 to the leaves. The community analysis of stems and leaves identified bacterial genera, including Acinetobacter, Klebsiella, Escherichia, Corynebacterium, and Streptomyces. Significant differences were also observed between organs in the functional annotations. The dominant functional categories were associated with cell signaling and protein metabolism in both organs. Full article

The study aims to investigate the skin microbiome composition of Yaks and the effects of different dietary nutrient levels on the skin microbiome diversity and metabolites. A total of 19 healthy Tianzhu White Yaks at two age stages (2.5 and 4.5 years old) were selected and fed either a high-energy diet (n = 9) or a low-energy diet (n = 10). After 90 days of feeding, skin microbiota and skin tissue metabolites were detected using 16S rRNA sequencing and LC-MS/MS untargeted metabolomics, respectively. The results showed: (1) the phyla Firmicutes, Actinobacteriota, Proteobacteria, and Bacteroidetes exhibited relatively high abundances in the skin of yaks, and the total abundance of these four phyla reached as high as 99.3%. Alpha diversity analysis indicated that the alpha diversity index of yak skin microbiota was significantly higher (p < 0.05) in the low-energy nutritional level group than in the high-energy nutritional level group in yaks of both 2.5 and 4.5 years of age. Principal coordinate analysis (PCoA) revealed a distinct separation of all skin microbiota samples into two clusters: the high-energy (H) and low-energy (L) groups. (2) A total of 114 differentially expressed metabolites were screened across both groups, significantly enriched (p < 0.05) in pathways including synaptic vesicle trafficking and glycerophospholipid metabolism; (3) Correlation analysis between microbiota and metabolites revealed significant positive correlations (p < 0.01) between Psychrobacter and choline, and between Corynebacterium and palmitic acid. In conclusion, A low-energy diet increases skin microbial diversity, which is beneficial for maintaining community stability; In contrast, a high-energy diet enriches bacterial genera such as Corynebacterium and Psychrobacter, enhancing functions related to antibacterial activity and barrier protection. Full article

Caseous lymphadenitis (CLA), an infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis), poses a significant economic burden to the global small ruminant industry. This study aimed to investigate genetic variations in the CP40 gene of C. pseudotuberculosis and to develop a rapid detection assay for enhanced pathogen identification. Homology analysis was performed to compare the CP40 gene sequence of the FJ-PN strain with other Corynebacterium species. Specific primers targeting CP40 were designed, and a SYBR Green I-based real-time PCR protocol was optimized. The assay’s specificity, sensitivity, and reproducibility were subsequently validated. The FJ-PN strain exhibited ≥99.65% nucleotide identity and ≥98.94% amino acid identity with C. pseudotuberculosis biovar ovi reference strains, showing 90.18–91.84% nucleotide identity and 88.63–90.77% amino acid identity with C. pseudotuberculosis biovar equi, and ≤82.71% nucleotide identity and ≤78.63% amino acid identity with other Corynebacterium species. The established qPCR assay demonstrated high specificity, the limit of detection was 52 copies/μL, and it demonstrated good reproducibility (intra- and inter-assay CV < 1.0%). Clinical sample testing revealed 18.8% positivity rates in nasal swabs, which was higher than that detected by conventional PCR (16.3%). These results indicate that the CP40 gene is evolutionarily conserved and represents a specific molecular marker for the identification of C. pseudotuberculosis biovar ovis. The developed SYBR Green I real-time PCR assay enables the efficient detection of C. pseudotuberculosis and provides technical support for CLA surveillance and control. Full article