Folia microbiologica最新文献

Autophagy is an essential intracellular degradation and recycling system for macromolecules and organelles, crucial for cell survival under nutrient stress conditions. In fungi, the genes involved in vesicle assembly during autophagy have been extensively characterized. However, in the pathogen Cryptococcus neoformans, the autophagy pathway remains less understood, particularly regarding its potential connections with virulence and pathogenicity. Our previous work identified Gpp2 as a key player in the biosynthesis of the sulfur-containing amino acid methionine. Through transcriptomic analysis, we observed that through transcriptomic analysis, we observed that deletion of GPP2 in C. neoformans leads to the repression of several core autophagy genes (ATG1, ATG2, ATG4, ATG15, VPS15, and VPS30), likely as an indirect consequence of altered methionine metabolism, while upregulating PEP4 expression. Since methionine is known to repress autophagy in Saccharomyces cerevisiae, we hypothesized that this amino acid might similarly regulate autophagy in C. neoformans. Our experiments demonstrated that both endogenous and exogenous methionine inhibit the expression of autophagy-related genes not only in the wild-type H99 strain but also in gpp2Δ and gpr4Δ mutant strains. Intriguingly, we found that GPR4 deletion creates a mutant unable to sense exogenous methionine, consequently releasing the repression of autophagy genes. Furthermore, microscopic analyses revealed that methionine supplementation substantially reduces autophagosome formation compared to methionine-deprived conditions. These results lead us to conclude that methionine biosynthesis regulation in gpp2Δ strains affects autophagy similarly to S. cerevisiae; GPR4 encodes a functional methionine receptor in C. neoformans; and methionine availability directly impacts autophagic flux, where the methionine receptor Gpr4 links extracellular amino acid availability to the intracellular control of autophagy likely via the Cys3/Gpp2 regulatory axis. This work provides crucial insights into the metabolic regulation of autophagy in pathogenic fungi and opens new avenues for understanding fungal pathogenesis mechanisms.

Methicillin-resistant Staphylococcus aureus (MRSA) is indeed a significant public health issue, affecting millions of people worldwide which can range from mild skin infections to life-threatening conditions like bloodstream infections and pneumonia. The aim of the current study is to decipher the possible mechanism of some selected natural compounds against MRSA. The natural compounds were selected based on our earlier systematic literature review. The selected compounds were screened against various targets of MRSA using molecular docking techniques. The stability of selected compounds was checked using molecular dynamics. Further, Absorption, Distribution, Metabolism and Excretion (ADME) was predicted using QikProp module. All the computational studies were conducted using the Schrodinger Maestro version 13.5.128. In-vitro assays were conducted to check the anti-bacterial effects of selected natural compounds against MRSA. Among 60 selected natural compounds, theasinensin A, xanthohumol, luteolin, oxyresveratrol, liquiritigenin and baicalin has shown the energetically favoured binding conformation in the active site of targets. Further, molecular dynamics results have shown the stable conformation of xanthohumol and theasinensin A in the active site of targets. Further, the pharmacokinetic profile of xanthohumol was found to be better among other natural compounds. The minimum inhibitory concentration (MIC) of xanthohumol was found to be 3.12 µg/mL as indicated by disk diffusion and micro broth dilution assays. Xanthohumol can be promising anti-bacterial agent against MRSA through multi modal mechanism. However, further detailed experimental studies are required to confirm its possible antibacterial mechanisms.

Plant-derived antimicrobials have been extensively studied due to their strong activity against foodborne and spoilage microorganisms, as well as their availability from diverse and cost-effective natural sources. A wide range of bioactive plant compounds, including phenolics, essential oils, alkaloids, lectins, and antimicrobial peptides have demonstrated significant potential in controlling microbial contamination in food systems. This review uniquely integrates advances in the extraction, purification, and molecular characterization of plant extracts and their bioactive antimicrobial compounds, along with insights into their mechanisms of action and in silico discovery approaches. Among these diverse bioactives, phenolics, essential oils, and antimicrobial peptides have shown the most promising potential for food applications. Recent progress in molecular docking and molecular dynamics simulations has accelerated the identification and optimization of plant antimicrobials, revealing their possible roles in inhibiting quorum sensing and biofilm formation. Despite these advances, knowledge gaps remain regarding their safety, stability, and interactions within complex food matrices, which must be addressed for industrial application. Overall, this review highlights both the opportunities and challenges in employing plant-derived antimicrobials as sustainable alternatives to synthetic preservatives, aligning food safety with consumer demand for natural products.

Urbanization has intensified the demand for different sustainable energy-generating solutions. One promising approach is the treatment of wastewater using electrochemical setups. A microbial fuel cell (MFC), an electrochemical setup, can be highly effective for wastewater treatment as it simultaneously generates bioelectricity. This study focuses on the isolation, characterization, and evaluation of electrogenic fungal species from wastewater samples (WWS) collected from the Uttarakhand region. Using the potentiostat, an electrochemical workstation, we screened a total of 70 different fungal isolates and identified 10 distinct fungal strains as potent current generators. Morphological characterization of these strains revealed several fungal structures, including hyphae and spores. The most potent fungi were further analyzed based on Polymerase Chain Reaction (PCR) amplification and genomic sequencing of the internal transcribed spacer (ITS) region. The obtained sequences were subjected to Basic Local Alignment Search Tool (BLAST) analysis, and the corresponding fungal isolates were assigned genus names after comparison with representative sequences available in GeneBank. ITS sequencing for the top three potent fungi revealed their highest resemblance to Aspergillus flavus (99.09%), Diaporthe caryae isolate KM 19 (96.18%), and Montagnula donacina (100.00%). Among these, the strain closely related to Aspergillus flavus demonstrated the highest current output. This isolate has been successfully submitted to the National Center for Biotechnology Information (NCBI) database under the accession number PX226319. The selected strain will be integrated into a dual-chambered microbial fuel cell (DC-MFC) system to evaluate its bioelectric performance under optimized conditions. Overall, this research established a foundation for identifying the potent fungal strains from local microbial communities present in wastewater for sustainable energy production.

Glutathione (GSH) serves as an essential guardian for parasites, protecting them from the onslaught of oxidative stress. As hemoglobin breaks down and energy is harvested through the intricate mitochondrial respiratory pathway, GSH meticulously creates a reducing environment, akin to a fortress against oxidative damage. The metabolic pathways involving GSH in parasites are complex and markedly different from those in human hosts, rendering them a compelling target in the battle against multidrug-resistant parasites. This review illuminates the critical role of GSH in the survival of malaria parasites and the impact of key enzyme inhibitors on the GSH redox pathway. Recent discoveries surrounding significant enzyme inhibitors as GST, GR, GS, and GP, are explored, shedding light on the potential of combination therapies while underscoring the obstacles posed by selective drug targeting and the imperative to navigate drug resistance. Moreover, the review delves into the forefront of research on the metabolic pathways of GSH in parasites, unveiling a trove of promising drug targets for strategies aimed at treating malaria in an era plagued by multidrug resistance and offers hope for innovative therapeutic approaches against one of the world's most persistent diseases.

Rapid industrialization, technological advancement, excessive use of chemical fertilizers, and ongoing climatic fluctuations have collectively imposed severe stress on global agricultural productivity. Among the various environmental pollutants, hexavalent chromium (Cr (VI)) poses a substantial threat to plant growth and soil fertility due to its high toxicity, mobility, and bioavailability. Cr (VI) disrupts the biosynthetic pathways of essential phytohormones, particularly auxins, by inhibiting enzymatic activities and cellular signaling mechanisms, ultimately leading to reduced crop yield and impaired physiological functions. To mitigate such effects, the exploration of robust microbial candidates capable of tolerating heavy metal stress while promoting plant growth is imperative. In the present study, a novel thermophilic bacterium, Brevibacillus borstelensis SSAU-3T, was isolated and characterized for its dual ability to withstand Cr (VI) toxicity and synthesize auxins under elevated temperature conditions. The strain demonstrated significant auxin production in the presence of Cr (VI) concentrations up to 20 ppm, beyond which a gradual decline was observed. Optimization studies revealed that maximum auxin synthesis occurred at pH 7.0, temperature 55 °C, tryptophan concentration of 1%, and an incubation period of six days, while salinity exhibited negligible effects up to 100 g/L. Among the various nutrient sources tested, lactose and tryptone were identified as the most effective carbon and nitrogen sources, respectively, for optimal auxin synthesis. The auxins produced were extracted using solvent partitioning and analyzed via Thin Layer Chromatography (TLC), which revealed variation in auxin profiles depending on the nutritional composition of the growth medium. Further confirmation and structural elucidation were achieved using Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR), validating the synthesis of indole-based auxin derivatives and associated metabolites. This study highlights the biotechnological potential of B. borstelensis SSAU-3T as a thermophilic, Cr (VI)-tolerant, auxin-producing microorganism with direct applications in sustainable agriculture. Its use as a bioinoculant in chromium-contaminated or high-temperature soils offers an eco-friendly and resilient strategy for restoring soil health and enhancing crop productivity in stress-prone agroecosystems.

Climate change induced abiotic stresses pose a major challenge to global food security, particularly in crops grown in marginal environments such as finger millet. The use of plant growth-promoting bacteria has emerged as a promising strategy to alleviate the detrimental impacts of stress and enhance plant development. In the present study, we investigated 30 bacterial isolates from finger millet rhizosphere and prioritized them based on their plant growth-promoting attributes using Bonitur Scale. Sixteen isolates were further evaluated for key competence traits, including tolerance to salinity, temperature and drought, antibiotic resistance, amylase production, biofilm and exopolysaccharide (EPS) formation, and root colonization ability. Three EPS-producing and drought-tolerant isolates (A11, P1a and B16a) were selected for pot experiments to assess their role in mitigating drought stress in finger millet. Inoculated plants showed significantly improved growth under water stress compared to uninoculated controls. Enhanced total sugars, proteins, phenolics, catalase activity, delayed wilting and better chlorophyll retention contributed to the improved drought tolerance of bacterized seedlings. Field evaluation of eight isolates further demonstrated reduced blast incidence and improved crop performance. Based on 16 S rRNA gene sequence analysis, four potent strains (A10, A11, P1a and B16a) were identified as belonging to the genus Bacillus. These isolates exhibit strong PGP and stress-alleviating capacities, highlighting their potential as effective bioinoculants for improving finger millet productivity under climate-induced stress conditions and supporting sustainable agriculture.

Cutaneous leishmaniasis is the most common form of the vector borne parasitic disease, causing skin lesion and ulcer. Several studies have reported the resistance of cutaneous leishmaniasis parasite to antimonial drugs. Hence, there is a need to develop cheaper and effective alternative therapies for resistance breakdown. In the current study we report the effectiveness of Teucrium stocksianum extract mediated green synthesized zinc oxide nanoparticles (ZnONPs) against Leishmania tropica (KMU25), a causative species of cutaneous leishmanaisis. ZnONPs was successfully synthesised at 70 °C by continuous stirring (2 h) of aqueous extract (5 mg/mL) and Zinc acetate solution (2 g/50 mL, pH: 8) in 1:9. The characterization of these NPs showed a UV-Vis surface plasmon resonance at 365 nm, hexagonal morphology with irregular shapes through scanning electron microscopy, average crystal size 21.48 ± 5.2 nm through XRD analysis and the complex metabolites attachments to the surface of the particles was confirmed by FTIR. The DPPH (2,2-diphenyl-1-picrylhydrazyl) assay-based antioxidant activity showed 50% free radical scavenging at 624.94 µg/mL and 798.45 µg/mL for extract and ZnONPs, respectively. The hemolysis assay revealed moderate cytotoxicity with a LD₅₀ value of 3807.54 µg/mL and 1537.16 µg/mL for the extract and ZnONPs, respectively. The antileishmanial activities were examined at different concentration (50, 100, 250, 500, and 1000 µg/mL) using MTT cell viability assays. The LD₅₀ values 1895.63 µg/mL (for extract) and 837.07 µg/mL (for extract mediated ZnONPs) were estimated, showing enhanced antileishmanial activity of ZnONPs compared to the extract. Moreover, the ZnONPs were nontoxic towards normal RBCs, making it a potential candidate as an interesting topical nanomedicine against cutaneous leishmaniasis.