Archives of Microbiology最新文献

Pseudomonas aeruginosa, a gram-negative opportunistic pathogen, exists in both biofilm and planktonic lifestyles, with biofilms playing a crucial role in chronic infections. Extracellular vesicles (EVs), secreted in both states, are known to mediate intercellular communication, but their compositional and functional differences remain poorly understood. This study systematically investigated the physicochemical properties and proteomic profiles of EVs derived from both planktonic and biofilm. Proteomic profiling revealed distinct signatures, with biofilm-derived EVs (BEVs) enriched for virulence factors and proteins associated with bacterial adhesion and iron acquisition, including FptA, PA4218, PhzB2, PhzS, and PhzG1. Functional assessments indicated that these compositional differences influence bacterial behaviors, particularly affecting biofilm adhesion, antibiotic tolerance, and iron chelation. The role of EV-associated siderophores was specifically investigated; however, determining whether they function as direct iron ion transporters proved inconclusive. Although these iron carriers induced downregulation of the fur gene—a key regulator of iron homeostasis—this effect occurred independently of external iron availability, suggesting a potential signaling role beyond simple iron transport.

Antimicrobial resistance in Staphylococcaceae poses a serious threat to human and animal health, driving the search for alternative strategies such as bacteriophage therapy. Here, we describe the isolation and characterization of pTJK, one of the first bacteriophages reported to infect Mammaliicoccus lentus, recovered together with its host strain TJK24 from sewage-contaminated stream water. pTJK is a novel lytic phage with a broad host range, capable of infecting multiple Mammaliicoccus and Staphylococcus species. It significantly reduced biofilm formation and disrupted preformed biofilms, including in non-host strains, and displayed synergistic activity with gentamicin and erythromycin. The phage remained viable under moderate temperature and pH variations, UV exposure, and chloroform treatment. Genome analysis revealed a 135.8 kb double-stranded DNA genome with 231 ORFs, including multiple endolysins and depolymerases potentially involved in antibiofilm activity, and no detected resistance or host virulence genes. Comparative genomics placed pTJK within the genus Sciuriunavirus, representing a novel yet-to-be-defined species. These findings highlight the rarity, genomic distinctiveness, and biotechnological potential of pTJK, reinforcing the relevance of Staphylococcaceae phages as promising tools to combat antimicrobial resistance.

The Brazilian Atlantic Forest, a critical biodiversity hotspot, plays a vital role in climate regulation and water conservation. To explore the relationship between tree diversity and soil bacterial communities, soil samples were collected along an edapho-climatic gradient. We hypothesized that tropical forest soils, among Earth’s most complex biological environments, exhibit predictable microbial community assembly patterns driven by deterministic processes. Specifically: (i) tree composition influences bacterial communities more strongly than abiotic factors when environmental heterogeneity is low, following niche-based assembly rules; (ii) specific tree taxa function as keystone species, shaping bacterial communities through microhabitat modification. Our findings indicate that tree diversity had a greater influence on shaping bacterial communities than soil attributes. Of the 72 tree species identified, Senegalia recurva, Araucaria angustifolia, Styrax acuminatus, Ilex paraguaiensis, Eugenia subterminalis, and Pisonia ambigua were key drivers of soil bacterial diversity. Additionally, late-successional tree species that require high light were closely linked to predicted microbial cycling of carbon, nitrogen, sulfur, and phosphorus. These results offer a hypothesis-generating framework for evaluating species selection in Atlantic Forest restoration projects, suggesting that these species represent candidates whose effects can enhance soil health and ecosystem functionality in reforestation programs.

In this study, mango fruit trees cv. Kent (Mangifera indica L.) grown in Nayarit, Mexico, during the 2024 and 2025 seasons were preharvest-treated with four applications of microencapsulated Meyerozyma guilliermondii LMA-Cp01 (0.4 g L⁻¹), either alone or combined with sodium benzoate (SB, 1 g L⁻¹) to manage anthracnose disease. Benomyl served as a positive control, while untreated trees were considered negative controls. The impact of preharvest treatments on mango trees’ flowering and bud development was examined, and population dynamics of M. guilliermondii on flowers and fruit surfaces were monitored. Postharvest evaluations included natural anthracnose incidence, severity index, and fruit quality under two storage conditions. Flowering and bud development were unaffected by any treatment. M. guilliermondii successfully adhered to and colonized flower and fruit surfaces, maintaining its viability throughout the experiments. All tested treatments significantly reduced anthracnose incidence and severity. Individually, microencapsulated M. guilliermondii or SB showed limited efficacy, whereas their combination demonstrated additive and synergistic effects, achieving higher anthracnose reduction. Combined treatments performed comparably to Benomyl across both seasons. Postharvest spraying did not enhance bio-efficacy beyond preharvest applications. Overall, the biofungicide combining M. guilliermondii with SB consistently reduced anthracnose and maintained fruit quality, representing a promising alternative to chemical fungicides for sustainable mango production.

Antimicrobial resistance has emerged as one of the major global health threats, driving the search for innovative strategies to combat chronic and recurring infections, particularly associated with biofilm formation. Biofilms confer strong tolerance to traditional antibiotics by shielding microbial communities within an extracellular matrix, posing significant challenges in clinical settings, especially in device-associated infections. Conventional antibiotics often fail to eradicate these complex biofilm structures, underscoring the need to explore alternative therapeutic strategies. Over the past decade, metal-based complexes have emerged as promising alternatives due to their unique modes of action and physicochemical properties. The integration of organic and inorganic chemistry, metal-ligand interactions in metal complexes, exhibits diverse mechanisms of action, including ROS production, enzyme inhibition, membrane cleavage and delayed resistance, representing a compelling frontier in addressing the global AMR crisis. This review highlights the dual role of metal complexes in antimicrobial and antibiofilm applications, with emphasis on silver, copper, palladium, gold, zinc, ruthenium, platinum and other complexes, reinforcing their potential as next-generation therapeutic antimicrobials.

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Despite advances in reproductive medicine, the role of microbes in infertility remains underexplored. Our earlier research demonstrated an Escherichia coli strain, capable of causing 100% sperm immobilization via agglutination in-vitro, and infertility in-vivo. Also, sperm agglutination factor (SAF), extracted and purified from bacterial culture, depicted similar results and, showed homology to glutamate decarboxylase. However, it remained unclear whether such bacterial protein signatures are produced within the vaginal milieu post-colonization of E. coli in host environment. Addressing this, discovery-phase proteomics approach was used to investigate vaginal lavage fluid (VLf) of female mice following intravaginal administration of E. coli. VLf from E. coli-administered and PBS-treated groups revealed distinct protein banding patterns (SDS-PAGE) and chromatographic profiles (RP-HPLC). Proteomic-profiling of pooled VLf using nano-LC-MS/MS depicted a ~ 20-kDa bacterial protein, annotated as Uncharacterized protein YfgI, only in test group. Gel-filtration chromatography of VLf revealed a purified protein of ~ 20-kDa that aligned with the proteomic analysis and hence, designated as VLf-protein. Functionally, VLf-protein impaired sperm motility, viability, induced ultrastructural abnormalities, demonstrated binding to sperm surface, and infertility in-vivo. Structural modeling and comparative analysis revealed only suggestive similarity between VLf-protein and SAF.

Recent advances in biomanufacturing have stimulated the exploration of microbial platforms for pigment production, offering alternatives to plant-derived and synthetic colorants. Among these biological solutions, microbial carotenoids, a group of naturally occurring pigments, have emerged as particularly valuable due to their vibrant red, orange, and yellow coloration coupled with demonstrated antioxidant capacity and health-promoting benefits. Sporobolomyces pararoseus, one of the most well-studied oleaginous red yeasts, exhibits a remarkable ability to simultaneously produce three commercially valuable carotenoids—β-carotene, torulene, and torularhodin—under scalable fermentation conditions, making it an attractive microbial platform for industrial biotechnology. This review summarizes current knowledge on S. pararoseus as a promising microbial cell factory for carotenoid production, emphasizing its distinctive biological characteristics and environmental adaptability, enzymatic pathways governing carotenoid synthesis, state-of-the-art biotechnological interventions to enhance productivity and recovery efficiency, and potential commercial applications across diverse biotechnology sectors. Current challenges in carotenogenic pathway optimization, genetic tool development, scale-up economics, and market regulatory construction are addressed alongside integrated solutions employing CRISPR-based genome editing techniques, multi-omics profiling approaches, circular bioeconomy strategies, and comprehensive safety evaluation procedures. Through synthesis of contemporary scientific understanding with innovative bioprocessing techniques, this review connects fundamental insights into S. pararoseus biology with actionable methodologies for commercial-scale implementation, and suggests that this yeast could serve as a microbial platform for sustainable production of β-carotene, torulene, and torularhodin to meet global market demands.

The growing bacterial antimicrobial resistance is one of the most serious global challenges, undermining the effectiveness of conventional antibiotics and increasing morbidity and mortality across human and animal populations. Within the One Health framework, which emphasizes the interconnectedness of human, animal, and environmental health, interdisciplinary strategies are crucial for addressing this threat. Despite ongoing efforts, current approaches have not slowed the spread of resistant pathogens, underscoring a critical gap in the development of alternative therapeutics. This review addresses this gap by examining three promising strategies: phytotherapy (plant-derived antimicrobials), phage therapy (bacteriophage-based bacterial targeting), and antimicrobial peptides (membrane-disrupting bioactive molecules). These innovative approaches may serve as alternatives or adjuncts to traditional antimicrobials and are highly relevant to One Health applications. Emphasis is placed on their mechanisms of action, therapeutic efficacy, recent advances, and the challenges they pose for research.

This study describes cyanobacterial diversity and toxicity of Microcystis aeruginosa detected in Umiam Lake and Ward’s Lake of Meghalaya, India. The WGS analyses of one-time enriched lake water sample in BG-11 medium showed the presence of many cyanobacteria including harmful Microcystis aeruginosa. The PCR using DNA extracted directly from lake water showed the presence of microcystin producing gene (mcyA). Two Microcystis spp were isolated from Umiam Lake water (25° 39′ 11.52" N 91° 53′ 3.48" E) and identified by 16S rDNA sequence analysis. The HPLC analysis revealed microcystin-RR in the methanolic crude extract from one of the isolates, which was further confirmed by LC–MS/MS analysis. The toxicity investigation of crude extract using male and female mice showed necrosis, and LD₅₀ values at 304 mg/kg bw and 366 mg/kg bw, respectively. Hepatic enzyme markers ALP, SGPT, and SGOT showed a sharp increase in toxin treated mice. Further, histology and scanning electron microscopy depicted marked changes in overall liver architecture, revealing the hepatotoxic nature of the crude extract. The overall result underscores the need for evaluation of toxin producing cyanobacteria in waterbodies across the NE region.

The investigation of bioactive phytochemicals from Anacardium occidentale (cashew) nut has attracted increasing interest, particularly due to their potential antifungal properties against Cryptococcus neoformans. In this study, molecular docking analysis were employed to assess the interaction strength of selected compounds with crucial enzymatic targets, including farnesyltransferase (CnFTase), beta-carbonic anhydrase (β-CA), and adenylosuccinate synthetase (AdSS). Molecular dynamics simulation was performed using the iMODS server, in order to check the stability as well as mobility in the receptor-ligand complexes following molecular docking. To evaluate the pharmacokinetic behavior, a multiparametric optimization (MPO) approach was applied, considering parameters such as membrane permeability (PAMPA), metabolic processing via cytochrome P450 (CYP450) enzymes, and clearance rates (Cl_{int, u}, Cl_Micro, Cl_Hepa). The degree to which the ligands resemble drugs was evaluated using drug-likeness scores (QED and MCE-18). Protein structures were retrieved from the Protein Data Bank and preprocessed using AutoDockTools™, with docking simulations conducted via AutoDock Vina. The methodology incorporated a Lamarckian Genetic Algorithm combined with an exhaustive search strategy. In the course of the present study, 13 compounds were examined, and four of these were identified as leads: catechin, epicatechin, naringenin, and pinostrobin. This determination was made in accordance with the MPO criteria. These molecules exhibited both high permeability in Caco-2 and MDCK models and favorable hydration free energies (ΔG_hyd ≤ -5.0 kcal/mol). Futhermore, naringenin and pinostrobin were demonstrated to undergo metabolic transformation by CYP450 enzymes in hepatic microsomes, indicating limited metabolic stability. The docking results indicated strong binding affinities (E_A≤ -6.0 kcal/mol) to CnFTase and AdSS, underscoring their potential as enzyme inhibitors through interactions within the active site, including residues associated with fluconazole binding site. Molecular dynamics simulations indicated a smaller conformational torsion of the Cα of the CnFTase and AdSS structures, suggesting that collective movements for both protein-ligand complexes are stable. The results suggest that these lead compounds are a starting point for new antifungal drugs inhibiting C. neoformans.