Folia microbiologica最新文献

Ethyl methanesulfonate (EMS) is a strong alkylating agent commonly used to induce random point mutations, particularly G: C to A: T transitions, by ethylating guanine bases in DNA. Its mutagenic properties, which stem from the transfer of ethyl groups to nucleophilic sites within cells, allow for the creation of various mutant libraries, aiding research in bacterial physiology, metabolism, and antibiotic resistance. This review briefly examines the mechanisms behind EMS mutagenesis and its applications in both forward and reverse genetics. In forward genetics, mutants generated by EMS with altered traits help identify the genetic mutations responsible, while reverse genetics focuses on analyzing specific gene functions. Although there are challenges like mutation stability and reversion, advancements in high-throughput screening methods have improved the effectiveness of EMS mutagenesis. The review also emphasizes the significant impact of EMS-induced bacterial mutants in promoting sustainable agriculture and environmental management. Notable examples include the creation of non-pathogenic Ralstonia solanacearum mutants for controlling bacterial wilt, as well as Bacillus and Pseudomonas mutants that enhance biosurfactant production and bioremediation efforts. Furthermore, EMS mutagenesis has led to the development of stress-tolerant strains that can survive under drought, salinity, and heavy metal conditions, along with strains that improve phosphorus solubilization and nitrogen fixation, contributing to better soil health and plant growth. By connecting fundamental research with practical applications, EMS mutagenesis remains a vital tool for tackling global issues in agriculture, environmental sustainability, and microbial biotechnology.

Thevetia peruviana (Pers.) K. Schum., commonly known as yellow oleander, is a toxic evergreen shrub harbouring pharmacologically active compounds with untapped biocontrol potential. The present study provides the first species-level investigation of fungal endophytes from the root, bark, flower, and fruit of T. peruviana, highlighting their enzymatic and biocontrol potential. Seven species have been reported for the first time from Thevetia peruviana: Pseudoascochyta pratensis TP-RF5, Neocosmospora rubicola TP-RF14, Botryotrichum geniculatum TP-BF1, Colletotrichum aotearoa TP-BF4, Botryosphaeria wangensis TP-BF8, Diaporthe sennicola TP-BF12, and Nothophoma macrospora TP-FlF1. Some of them exhibit significant hydrolytic enzyme activity, particularly chitinase and cellulase, and demonstrated substantial inhibition (≥ 50%) of phytopathogens (Fusarium oxysporum, Fusarium fujikuroi, Alternaria calandulae and Aspergillus nishimurae). Correlation analyses revealed a significant positive correlation between chitinase activity and antifungal efficacy, highlighting the prominent role of enzymatic degradation in biocontrol. In contrast, cellulase activity was negatively correlated with Fusarium spp., which might be indicative of complex interactions. Catalase activity negatively correlated with biocontrol potential, indicative of indirect antagonistic effects, whereas amylase, lipase, and protease showed no significant association with antifungal efficacy. Overall, the study underscores the biocontrol and biotechnological potential of T. peruviana endophytic fungi and warrants further investigation of their metabolites and in vivo efficacy.

Klebseilla pneumoniae, poses a major health concern and its lipopolysaccharide act as a potential immunogenic target for vaccine production. The study was aimed to extract, characterize and structural analysis of lipopolysaccharide from local clinical isolate of Klebseilla pneumoniae by using different analytical techniques. In January 2024 due to large number of pneumonia infections, clinical sample of Klebseilla pneumoniae was collected from tertiary care hospitals of Punjab, Pakistan. Bacterial strain was characterized and antibiotic testing was performed using disk diffusion method. Lipopolysaccharide was extracted, quantified and characterized by various analytical methods such as Limulus Amebocyte Lysate (LAL) assay, SDS-PAGE, High Performance Liquid chromatography (HPLC), Fourier Transfer Infrared spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS). Results showed that Klebseilla pneumoniae had highest resistant to most β-lactams and aminoglycosides whereas less sensitive to colistin, merpenem and imipenem. Hot phenol-water method yields purified lipopolysaccharide that was further confirmed by SDS-PAGE that demonstrated O-polysaccharide and lipid A moiety. While HPLC revealed 80-90% purity compared with commercial standard. FTIR spectrum showed distinctive peaks at 3331.10 cm⁻¹, 2216.21 cm⁻¹, 1982.82 cm⁻¹, and 667.37 cm⁻¹, corresponding to hydroxyl, alkyne/nitrile, carbon bonds, and pyranose ring structures, which revealed sugar moieties such as glucosamine that are key components of lipid A in lipopolysaccharide whereas GC-MS detected vital immunogenic components phenylephrine, 1-adamantane methylamine and α-bisabolol. It is concluded that lipopolysaccharide isolated from local isolate of K. pneumoniae represented the structurally validated and immunologically active biomolecules, act as a potential vaccine candidate to address antimicrobial resistance in developing countries.

Cationic steroid antimicrobials (CSA-ceragenin), which includes CSA44 and CSA 131, constitute a novel family of antimicrobial drugs. This study aims to examine the antibacterial and antifungal properties of CSA-44 and CSA-131 against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Enterococcus faecalis, and Candida albicans. Additionally, the cytotoxic effects of both compounds were addressed using dental pulp stem cell lines. The CSA-44 compound with a concentration of 0.05% yielded the lowest minimum inhibitory concentration (MIC) of 0.04 µg/mL against E. faecalis. The minimum inhibitory concentration (MIC) values for all concentrations of CSA-44 and CSA-131 against S. aureus ranged between 2.50 and 5.00 µg/mL. Inhibitory action against C. albicans was found to be most pronounced in CSA-131 and CSA-44. The 0.2% of CSA-44 yielded the highest minimum bactericidal concentration (MBC) value of 5.00 µg/mL against S. aureus. The 1xMIC of CSA-44 (0.2%) decreased the bacterial load against E. faecalis at 3 h, even though the same effect was recorded at 6 h against S. aureus. CSA-44 and CSA-131 prevented the growth at 1.5xMIC at 3 h, whereas 1xMIC concentration inhibited the growth at 6 h for all tested microorganisms. The lowest viability was observed with CSA-131 (0.2% 100%), whereas CSA-44 shows lower toxicity than CSA-131 at the same dose. This study provides the first comparative evaluation of the antibacterial, antifungal, and cytotoxic properties of CSA-44 and CSA-131 against clinically relevant endodontic pathogens, offering novel insight into the therapeutic potential of ceragenins in dental applications.

Soil salinization has emerged as a major constraint to global agricultural productivity, severely disrupting soil structure, nutrient cycling, and plant establishment. This study evaluates the functional potential of the cyanobacterium Desertifilum salkalinema SSAU-7 and the microalga Chlorella vulgaris SSAU-8 as bio-ameliorants for saline soils. Both isolates demonstrated high salinity tolerance and exhibited key plant growth-promoting traits, including indole-3-acetic acid (IAA) and hydrogen cyanide (HCN) production. Under escalating salt concentrations, D. salkalinema SSAU-7 and the mixed consortium maintained stable photosynthetic activity and enhanced extracellular polymeric substance (EPS) secretion, while C. vulgaris SSAU-8 showed reduced photo-physiological performance at 10 g L⁻¹ salinity. Soil microcosm experiments revealed that microbial inoculation facilitated the development of biological soil crusts (BSCs), which significantly improved soil physicochemical properties over 75 days. Notably, treated soils exhibited reduced pH (7.5-8.0), a 209% increase in total organic carbon, a 10% enhancement in porosity, and an 8% reduction in bulk density. EPS emerged as a critical driver of soil aggregation and fertility restoration by integrating essential structural components within the saline matrix. The BSC-amended soils further promoted Oryza sativa germination and early seedling vigor, underscoring the agricultural relevance of these microbial consortia. Collectively, our findings establish cyanobacteria-microalgae co-cultures as a promising eco-engineering strategy for reclaiming saline landscapes and strengthening soil resilience under salt stress.

The human microbiome, particularly the gut and reproductive tract microbiota, plays a critical role in regulating fertility through complex molecular and immunological mechanisms. This review synthesizes emerging evidence on the bidirectional communication along the gut-reproductive axis, emphasizing how microbial-derived metabolites, such as short-chain fatty acids (butyrate), bile acids, and indoles, modulate systemic inflammation, immune tolerance, hormone metabolism, and energy homeostasis. Dysbiosis, or microbial imbalance, is strongly associated with a range of reproductive pathologies, including polycystic ovary syndrome, endometriosis, premature ovarian insufficiency, impaired spermatogenesis, and recurrent implantation failure. Furthermore, site-specific microbiomes, such as Lactobacillus-dominated vaginal and uterine communities, are vital for successful implantation and pregnancy maintenance. External factors including diet, environmental toxins, and antibiotic use can disrupt these microbial ecosystems, whereas interventions like probiotics like Lactobacillus and Clostridium butyricum, prebiotics, postbiotics, and fecal microbiota transplantation offer promising avenues for restoring microbial and reproductive health. However, translational challenges remain, including methodological heterogeneity in microbiome research and the need to establish causal mechanisms beyond correlation. Future efforts should prioritize multi-omics integration, randomized controlled trials, and personalized microbiome-based diagnostics and therapeutics to effectively address infertility.

The escalating crisis of antibiotic resistance presents a formidable challenge to global public health and food security. Insects are increasingly recognized as significant reservoirs and vectors for antibiotic resistance genes (ARGs) which inhabit diverse ecosystems. This review explores how the insect gut microbiota contributes to the development and spread of antibiotic resistance, focusing on the mediating role of the host immune system. We outline the structural and functional dynamics of the insect gut microbiome and elaborate on direct mechanisms through which microbiota contribute to resistance, including ARG carriage, enzymatic inactivation of antibiotics, and modulation of host detoxification pathways. Special emphasis is placed on the bidirectional crosstalk between gut microbes and the host immune system: we discuss how immune effectors, particularly antimicrobial peptides (AMPs), exert selective pressures that may enrich resistant taxa, and how microbial metabolites reciprocally regulate immune activity. Key immune signaling pathways-Toll, Immune Deficiency(Imd), and Janus kinase-signal transducer and activator of transcription (JAK-STAT)-are explored for their roles in maintaining microbial homeostasis and modulating resistance phenotypes. We also highlight cutting-edge experimental approaches, including gnotobiotic models and multi-omics technologies, that are essential for elucidating causal relationships. We conclude by highlighting outstanding questions and outlining future research priorities that integrate microbiology, immunology, and computational biology. This review aims to establish a holistic framework for understanding the insect gut as a hotspot for antibiotic resistance evolution and to inspire innovative microbiome-based interventions.