Archives of Microbiology最新文献

Industrial discharges contaminated with synthetic dyes are responsible for causing serious harm to ecology and living beings. Current knowledge on microorganism-based technologies for removing dyes has been synthesized in this review. To promote scalability and safety in bioremediation, emphasis has been placed on single isolates, engineered and natural consortia, genetically modified strains, computational prescreening, the role of mediators and energy supplements, analytical workflows, and ecotoxicity assessment. In summary, multispecies consortia are more resilient than single isolates and can decolorize broad-spectrum dyes. Azoreductases, laccases, and ligninolytic peroxidases remain the dominant enzymes that catalyze this process. Sometimes, better mineralization in downstream processes is achieved with microaerophilic or sequential anaerobic‒aerobic systems. Prescreening by computational (docking, homology modeling, metabolic reconstructions) and in silico methods minimizes the time and labor required for selecting the appropriate candidate and provides critical insights into enzyme–dye complementarity. While a multiple-fold rate increase is achieved with additional redox mediators and co-substrates, treated effluent may also retain or generate toxic intermediates, which underscores that visual decolorization does not represent detoxification. Although the performance of the process can be improved by engineering principles (top-down enrichment, bottom-up synthetic consortia, and spatial immobilization) and targeted genetic transfers, biosafety and scale-up challenges are the major drawbacks of these processes. Industrial translation of microbe-based systems requires standardized toxicity assessments, the design of adaptable reactors, and regular containment and life-cycle assessments.

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Vesicles are a class of naturally released, cell-derived, lipid bilayer enclosed compartments. Different kinds of vesicles can be produced within cells. Cellular processes are heavily dependent on the synergistic action of some vesicles within cells. Studies have showed diverse roles of vesicles including intracellular trafficking, cell-to-cell communication and intracellular digestion. Vesicles can deliver not only some proteins and lipids to target sites but also viral components between nucleus and cytoplasm. Transmembrane transport of some viral nucleocapsids through intranuclear microvesicle is necessary for some viral propagation in host. Viral infection and viral spread are directly involved with vesicle-mediated endocytosis and exocytosis. So, the production of some progeny virion and viral release can be regulated by vesicle-mediated cellular transport and exocytosis. In the study, the classification, biogenesis and function of vesicles were summarized to better understand their role in viral propagation. In conclusion, vesicular trafficking can play important roles in regulation of viral entry, transport of viral substance and viral spread.

Heyndrickxia coagulans is a probiotic strain combining features of lactic acid bacteria and spore-forming bacilli. Its extracellular metabolites (postbiotics), including bacteriocins, organic acids, and short peptides, have gained increasing interest in skincare due to their antibacterial, anti-inflammatory, and antioxidant activities. In this study, Staphylococcus aureus was selected as a model pathogen to evaluate the antibacterial efficacy of H. coagulans metabolites using Oxford cup diffusion and minimum inhibitory concentration (MIC) assays. A 0.5 mg/mL sample produced a 12 mm inhibition zone, and the MIC against S. aureus was determined to be 400 µg/mL. Biofilm assays showed that all tested concentrations inhibited biofilm formation by more than 50% relative to the untreated control. Mechanistic investigations—including bacterial growth curve analysis, membrane permeability assays, and metabolic enzyme activity evaluation—demonstrated that these metabolites disrupted multiple physiological functions of S. aureus, exhibiting antibacterial performance approaching that of mild standard antimicrobials. Overall, this study highlights the potential of H. coagulans metabolites as safe and natural agents for skin health, providing a mechanistic foundation for developing functional skincare products aimed at preventing and controlling skin infections.

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L-Asparaginase (L-ASNase) (EC 3.5.1.1) produced by fungi has tremendous potential in the therapeutic and food processing sectors. In the present study, a newly isolated fungal strain, PVS1, identified as Fusarium solani (GenBank accession no. PQ721280; Indian Type Culture Collection no. ITCC 9504), produced a high amount of extracellular L-ASNase, 44.6 U/mL, on the 4th day in the modified Czapek Dox medium under submerged conditions. The production of L-ASNase was optimized using the One-Factor-at-A-Time (OFAT) approach, which demonstrated that the most suitable carbon and nitrogen sources were glycerol (2.0 g/L) and peptone (10.0 g/L), respectively, amended with L-asparagine (5.0 g/L). Additionally, F. solani PVS1 demonstrated high production of L-ASNase at a pH of 6.0 ± 0.2, incubation temperature of 37°C, and under shaking conditions, resulting in a maximum activity of 58.8 U/mL on the 3rd day. Partial purification of the enzyme was achieved through acetone precipitation and diethylaminoethyl (DEAE)-Sephadex ion exchange chromatography, resulting in a 3.53-fold purification with a recovery rate of 0.28%. The partially purified L-ASNase exhibited a molecular weight of approximately 70 kDa, with activity over an extended temperature range from 20 to 60 °C, and showed the maximum residual activity of 50.3% at pH 5.0 ± 0.2. Furthermore, L-ASNase exhibited stability with most of the tested metal ions. The K_m and V_max of the L-ASNase were 7.14 mM and 102.14 U/mL, respectively. The partially purified L-ASNase exhibited a high DPPH scavenging activity (IC₅₀ 0.51 ± 0.02 mg/mL). In conclusion, the results demonstrate that the F. solani PVS1 strain is a prospective candidate for producing L-ASNase and could be applied for subsequent applications in the pharmaceutical and food processing industries.

Gene-signatures for probiotic attributes expedite screening of novel probiotic strains as well as identify molecular basis of probiotic benefits. Therefore, strain-specific genomic-studies correlating functional-assays are in demand. Here, we present the same for Lactiplantibacillus plantarum LP-ARP2 using genomic-metabolomic-functional approaches. Genomic-features of LP-ARP2 are further compared with clinically relevant L. plantarum strains to elucidate gene-specific commonality. We find robust stress-resilience genetic set-up (usp/hsl/clp/ABC-transporters/ ATP-synthase/chaperons dna/gro/grp) in LP-ARP2-genome. Our acid/bile tolerance assays also indicate survivability (> 60%) of the strain in harsh conditions. Presence of adhesion-related (lspA/mapA/eno/srtA/glycosyltransferases/glycosylhydrolases/lipoproteins) and biofilm-forming genes (veg/luxS) further align with its efficacy in autoaggregation (> 60%), adhesion (Caco-2), and biofilm-formation (24 h). CAZyme-genes with significant prebiotic utilization indicate the strain’s ability for gut-microbial-modulation and adaptation. Metabolic-profiling of LP-ARP2-derived-CFS (HRMS analysis) validates the presence of related genes for SCFAs/vitamins/amino-acids/neurotransmitters GABA/serotonin/acetylcholine etc. Besides, many metabolites are reported antimicrobials. Indeed LP-ARP2 shows significant antibacterial potential against multidrug-resistant bacteria (Gram-positive/Gram-negative), gut-pathogen Salmonella Typhimurium and pathogenic-biofilm (MRSA). Presence of antioxidant-genes in LP-ARP2-genome (thioredoxin/NADH-dependent-nox/npr/ndh/glutathione-reductase/glutaredoxin/catalase/peroxidases/methionine sulfoxide reductase) are validated by high radical-scavenging activity of LP-ARP2 (ABTS > 40%, DPPH 25 U/mL, superoxide > 80%, and hydroxyl > 70%). Moreover, in-silico functional-network-analysis reveals LP-ARP2-derived metabolites target oxidative stress, neuroinflammation, amyloid-beta metabolism, tau-phosphorylation, neurogenesis, and synaptic function, indicating molecular relevance of the therapeutic potential of LP-ARP2. Fascinatingly, genomic-analysis between LP-ARP2 with clinically relevant (depression and intestinal disorders) L. plantarum strains (299v and Lp01) elucidate comparable genetic-features for beneficial probiotics. Thus, study offers potential gene-signatures for probiotic-benefits of L. plantarum and project LP-ARP2 as a promising probiotic with antibacterial, antioxidant and psychobiotic potential.

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Haematobia irritans (L.), the Horn fly, is an obligate bloodsucking ectoparasite of cattle. This is an insect that lives on cattle dung during its early stages (egg, larva, and pupa), whereas in its adult stage, it develops an exclusively hematophagous diet. This lifestyle shift involves a significant adjustment in metabolic capacities and could exert considerable pressure on shaping the community of microorganisms associated with each developmental stage. In this work, we hypothesize that anaerobic microorganisms dominate the larval microbial communities, while aerobic microorganisms dominate the adult stage. To test this hypothesis, we performed an amplicon sequencing of the 16S rRNA gene analysis to describe the bacterial community across the Horn fly's life stages. We found that early stages, such as the egg and larva, were dominated by anaerobic Clostridiales and then transitioned to one overwhelmingly dominated by Gammaproteobacteria in adulthood. A notable decline in alpha biodiversity was observed during the pupal-to-adult transition, accompanied by considerable species turnover, indicating the existence of ecological filtering processes. We also estimated genera as part of the microbial core, as well as differentially abundant bacteria that may be relevant for development in both the larval and adult stages. These findings provide a clear picture of the microbial ecological succession processes associated with the bacterial symbionts of this important insect pest.

Trypanosoma cruzi causes American trypanosomiasis or Chagas Disease, a neglected tropical disease with cardiac, digestive and neurological involvement that can be fatal, and for which there are few effective antiparasitic drugs. EF3 is an elongation factor with ATPase activity present in fungi, which are not present in mammalian; it is essential for protein synthesis in these organisms, this molecule is also present in some protist parasites, so the objective of this work was the determination and characterization of nucleotidases associated with polysomes of T. cruzi. The nucleotidase activity of T. cruzi polysomes was studied and compared with that found in human ribosomes. Epimastigotes of T. cruzi were processed by subcellular fractionation techniques, obtaining the fractions: kinetoplasts (K), polysomal (P) and soluble (S100). The ability to hydrolyze ATP in each fraction was determined measuring the inorganic phosphate (Pi) released. The total ATPase activity was distributed between K (11.6%) and P (9.4%), while S100 did not present activity. The highest specific activity was found in K (116 ± 1 nmol/Pi/mg protein), followed by P (83 ± 3 nmol/Pi/mg protein). The preferential substrate of polysomal nucleotidases was ATP, followed by GTP. Ouabain and vanadate inhibited polysomal ATPase activity by 39% and 68%, respectively. Sequence comparison analysis of EF3 and T. cruzi nucleotidases and molecular modeling were performed, demonstrating that nucleotidase activity does not correspond to a possible EF3 analogue in T. cruzi. Differences with human ribosomal ATPase could be exploited for chemotherapeutic control of the parasite.

Phytases hydrolyze phytic acid (myo-inositol hexakisphosphate), releasing inorganic phosphorus and essential minerals, thereby increasing their bioavailability for animals and humans. However, low native production and the limited stability of wild-type enzymes hinder their industrial applications. In this study, the PHY7227 gene from Talaromyces pinophilus was cloned and expressed in Komagataella phaffii, yielding a recombinant phytase with a specific activity of 371.29 U/mg. The identity of this phytase was confirmed by SDS-PAGE and LC-MS/MS. The recombinant phytase exhibited a molecular mass of ~ 75 kDa, maximum activity at pH 5.5 and at 55 °C and 60 °C and showed higher specificity for sodium phytate, exhibiting K_{m app} and V_{max app} values of 0.947 mM and 7.67 µmol×s^− 1, respectively, against this substrate. The enzyme showed significant thermostability at 50 °C and it was not inhibited by EDTA, DTT, or β-mercaptoethanol. In order to immobilize the phytase using the cross-linked enzyme aggregate (CLEA), 70% (v/v) isopropanol provided the highest CLEA immobilization yield, 83%, and activity recovery of 70.8%. Compared to the free form, the immobilized phytase exhibited enhanced thermostability at 50 °C and a broader pH activity range. The immobilized phytase maintained over 60% of its initial activity after ten cycles of reuse in sodium phytate hydrolysis. These results demonstrate the effectiveness of CLEA immobilization for the recombinant phytase and highlight its potential for industrial applications, especially in animal feed production.

Helicobacter pylori is a major human pathogen responsible for chronic gastritis, peptic ulcers, and gastric cancer. Its persistence is facilitated by a complex arsenal of virulence factors, including the CagA oncoprotein, the VacA toxin, adhesins, and the ability to form biofilms. While the roles of individual factors are well-studied, the integrated mechanisms by which they collectively drive carcinogenesis remain a critical knowledge gap. This review integrates evidence showing that CagA delivery and type IV secretion–dependent signals create a transient, infection-driven BRCAness (BRCA1/2 pathway deficiency) state, which is a homologous recombination DNA repair deficiency, promoting error-prone repair and genomic instability. Concurrently, CagA-independent pathways, such as T4SS-mediated ADP-heptose delivery and reactive oxygen species generation, contribute to DNA double-strand breaks. The infection further impairs host defenses by disrupting tumor suppressor pathways such as p53, dysregulating immune signaling of NF-κB and JAK/STAT, which results in immune evasion through arginine depletion and impaired antigen presentation. By elucidating the coordinated interplay among virulence factors, DNA damage response impairment, and immune modulation, this review highlights potential intervention nodes that may help disrupt persistent infection and ultimately reduce the risk of H. pylori-associated gastric cancer.

Postbiotics, defined as preparations containing inactivated microbial cells, cell fragments, and bioactive metabolites are increasingly recognized as next-generation functional ingredients owing to their superior safety, stability, and regulatory flexibility compared with live probiotics. Their capacity to modulate immune responses, exert antimicrobial effects, enhance metabolic homeostasis, and strengthen gut-barrier integrity without the risks associated with microbial viability or translocation makes them highly suitable for applications in foods, pharmaceuticals, animal feed, and aquaculture systems. Nevertheless, despite rapid commercial expansion, the scientific foundations and industrial processes required for consistent postbiotic production remain poorly integrated, with limited standardization across strain selection, inactivation strategies, and analytical quality metrics. This review highlights recent developments in targeted strain selection, controlled fermentation strategies, downstream processing innovations, and emerging thermal and non-thermal inactivation methods designed to preserve essential structural and metabolic components. It further examines downstream stabilization approaches such as microencapsulation, freeze-drying, and advanced filtration techniques that enhance product functionality and shelf stability. In addition, the review consolidates the expanding portfolio of commercial postbiotic formulations, outlines the microbial species employed, and summarizes the evidence supporting their health benefits across diverse application sectors. Particular emphasis is placed on technological innovations, including precision inactivation tools and multi-omics-driven characterization methods, which are progressively transforming postbiotics from conceptual laboratory entities into scalable industrial solutions. The review also highlights persistent challenges related to process standardization, compositional consistency, and global regulatory alignment, and proposes a structured framework to guide future research and product development. Overall, this work provides an integrated and future-oriented perspective intended to support researchers, industry stakeholders, and regulatory agencies in advancing the science, technology, and commercialization of safe, stable, and efficacious postbiotic products.

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