Archives of Microbiology最新文献

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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An experiment was conducted to isolate, identify, and characterize the soil bacteria capable of biodegrading untreated Low Density Polyethylene (LDPE) from selected locations of municipal corporation dumping stations in Thoothukudi, Southeast coast of Tamil Nadu, India. A total of 29 distinct bacteria were isolated using Tryptic Soya Agar (TSA) after enrichment of soil samples from the selected sites. Of which, two isolates produced maximum zone of clearance during screening and formed biofilm after 21 days of incubation. The 16 S rRNA sequencing confirmed that the isolates were identified as Paenibacillus timonensis (PX106822) and Cupriavidus nantongensis (PX106762) which resulted in the weight reductions of 3.15% and 1.83% respectively on untreated LDPE after 30 days of incubation. During degradation, the pH of the Mineral Salt Medium (MSM) increased from 6.73 to 8.06 and 8.11 respectively by the two isolates. In the present study, it was observed that the two isolates had increased viable cell count of 7.07 × 10⁸ and 3.83 × 10⁷ CFU/ml respectively with the initial attachment onto the LDPE films followed by biofilm formation, which favoured biodegradation of LDPE. Fourier Transform Infrared (FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM) analysis also confirmed that the two isolates had adhered and attacked on the surface of LDPE film thus serving as evidence for bacterial degradation of LDPE. This study concluded that the isolates had more capability in LDPE biodegradation and will serve as a baseline data for plastic litter management.

Microorganisms play pivotal roles in maintaining host physiology and ecosystem balance, with fish-associated microbiomes offering unique insights due to the diverse habitats and feeding behaviours of their hosts. This review comprehensively explores the diversity, composition, and functional roles of gut and skin-associated microbial communities in fish across freshwater, brackish, and marine environments, with emphasis on recent advancements in metagenomic methodologies. Culture-independent techniques, particularly high-throughput and third-generation sequencing technologies, have revolutionized our ability to uncover microbial diversity, gene functions, and interspecies interactions. The fish gut microbiome, heavily influenced by factors such as diet, habitat, and host species, contributes significantly to nutrient metabolism, immune modulation, and physiological adaptation. Similarly, the skin microbiota provides a critical first line of defence, offering protection through competitive exclusion and antimicrobial activity. Functional metagenomics reveals microbial contributions to host metabolism, energy homeostasis, xenobiotic degradation, and environmental adaptation via the gut-brain axis and metabolic pathways. Emerging evidence highlights the bidirectional relationships between microbiota and host phenotypic plasticity. This review underscores the importance of integrative metagenomic approaches to decode complex microbial functions and their ecological relevance in aquaculture, with implications for sustainable fish health management, disease prevention, and improved productivity.

Diatoms, a unique class of microalgae, play a pivotal role in global ecosystems due to their photosynthetic capabilities and adaptability to diverse aquatic environments. Composed of opaline silica, they serve as sensitive indicators for water quality monitoring. This review covers various diatom research techniques, including sampling and isolation. It highlights methods for different substrata, such as epiphyton, epipelon, and epipsammon, as well as traditional isolation approaches like agar plate methods and serial dilution. Automation techniques, such as flow cytometry (FACS), are also discussed. The review emphasizes the potential of diatoms for pollutant removal, particularly heavy metals, and presents various diatom-based indices for water quality assessment. Future research is encouraged to refine isolation techniques, enhance the effectiveness of indices, and explore biochemical pathways that could improve diatoms’ bioremediation capabilities, thereby fully leveraging their potential for environmental monitoring and remediation.

Food-borne bacterial pathogens remain a major public health concern, causing extensive illness and economic losses worldwide. Conventional detection methods are often slow and insufficient for identifying viable but non-culturable pathogens. Recent microbiological, biotechnological and bioinformatic advances have markedly improved food safety monitoring. Rapid molecular assays (PCR, qPCR, microarrays), next-generation sequencing, metagenomics, and emerging CRISPR-based diagnostics enable faster and more accurate pathogen detection and outbreak tracing. Bioinformatic tools—including genomic databases, phylogenetics, and machine-learning models—support predictive risk assessment and real-time surveillance. Preventive innovations such as bacteriophages, probiotics, antimicrobial peptides, nanotechnology-based interventions, and engineered microbes provide sustainable alternatives to chemical preservatives. Key challenges include variability across food matrices, biosafety considerations, and limited integration of multi-omics approaches into routine workflows. Overall, these emerging strategies offer improved precision and responsiveness for detecting and preventing food-borne bacterial pathogens.

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The emergence of CRISPR/Cas9 technology has transformed the landscape of gene editing, allowing for precise alterations in DNA that hold great promise for research and potential therapies. However, a significant concern is the occurrence of off-target effects, which can lead to unintended genetic modifications with potentially harmful consequences. This paper explores the nature of off-target effects in CRISPR/Cas9, discussing how they arise and their implications for the reliability of gene editing. We identify the challenges faced in detecting and predicting these off-target interactions, including limitations in current detection techniques and the complexities of cellular biology. We present strategies aimed at minimizing off-target effects, such as careful design of guide RNAs, the use of computational tools for prediction, and improved delivery methods. Through a review of case studies, we highlight successful cases where off-target activity has been significantly reduced, offering insights into best practices for enhancing the accuracy of CRISPR/Cas9 applications. Moreover, we provide a comparative overview of Cas9, Cas12, and Cas13 systems, emphasizing their distinct target specificities, mechanisms of action, and off-target profiles. This comparison offers a broader understanding of how alternative CRISPR effectors may be leveraged to improve genome and transcriptome editing precision. This study underscores the importance of continued research to address the challenges of off-target effects, ultimately supporting the development of safer and more effective gene editing methods for clinical use.