Archives of Microbiology最新文献

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.

A common vaginal dysbiosis, bacterial vaginosis (BV), has serious consequences for reproductive health, including an elevated risk of infertility and pelvic inflammatory disease. Its distinctive feature is a robust polymicrobial biofilm, mainly composed of Gardnerella species (spp.), which protects infections against antibiotic therapy and promotes high rates of recurrence. Concurrently, Chlamydia trachomatis (CT) is the most common bacterial sexually transmitted infection globally, with over 130 million new cases annually. A primary cause of tubal factor infertility, CT infection promotes adnexal adhesions and fallopian tube obstruction through inflammatory damage. This article reviewed two critical agents: CT, an intracellular bacterium that causes inflammatory tubal damage, and BV, caused by biofilm-forming pathogens such as Gardnerella. The growth of antimicrobial resistance underscores the critical need for targeted alternatives to broad-spectrum antibiotics. Endolysins, enzymes that break down bacterial cell walls, are produced by bacteriophages (phages) and represent a potential new treatment approach. This paper summarizes evidence that modified endolysins, such as PM-477, can specifically break down Gardnerella biofilms in vitro and ex vivo while preserving beneficial vaginal lactobacilli. We examine how this precise mechanism addresses the fundamental shortcomings of existing BV treatment. Then, to transform phage-derived techniques from an intriguing preclinical concept into a workable therapeutic intervention for recurrent BV, we critically assess the key translational obstacles that must be addressed, including pharmacokinetics, formulation, and the need for clinical trials.

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This study investigated the aerobic biodegradation potential of two novel indigenous bacterial strains, Pseudomonas aeruginosa DUT-Pa and Rhodococcus erythropolis DUT-Re, utilizing benzene, toluene, ethylbenzene, and o-xylene (BTEX) as the sole carbon source. The optimal metabolic activity for both strains was identified at neutral pH (7.0) and mesophilic conditions (30 °C), establishing a critical baseline for enhancing bioremediation protocols. Biochemical oxygen demand (BOD) analysis revealed a direct correlation between the substrate concentration (up to 400 mg/L) and microbial respiratory activity. Dissolved oxygen (DO) depletion from 7.77 mg/L (pre-experiment) to 2.97 mg/L (DUT-Pa) and 2.15 mg/L (DUT-Re) further confirmed the oxygen-dependent degradation. In the gas phase, the highest degradation rate was recorded for benzene, with 98.43, 97.34, and 98.91% by DUT-Pa, DUT-Re, and mixed bacteria, respectively. Meanwhile, the liquid phase demonstrated superior toluene degradation efficiency by DUT-Pa, DUT-Re, and mixed bacteria with 91.99, 83.54, and 93.27% respectively. Bacterial combinations enhanced BTEX degradation, achieving the shortest half-lives and the highest degradation rate constants. Meanwhile, the SOD (325 U/mL) level and MDA (1.5 to 2.59 nmol/g) increased in the mixed system. This study demonstrates that an additive effect of DUT-Pa and DUT-Re combination promotes efficient, complete degradation of BTEX and offers a scalable, eco-friendly solution based on strain-specific cooperative microbial dynamics.

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The accumulation of plastics in aquatic environments is a growing global concern, as biofouling on plastic debris leads to the formation of the plastisphere, an ecological niche for diverse microbial and macrofouling organisms. Although plastic characteristics such as size, color, and polymer type may influence plastisphere development, there is no consensus regarding their relative importance, and studies in estuarine environments remain scarce. Here, we investigated plastisphere formation across three salt marsh zones (dry, intermediate, and flooded) in the Patos Lagoon estuary (southern Brazil), considering variations in plastic size (6 × 2, 30 × 10, and 60 × 20 mm), color (white, black, and red), and polymer type (Polypropylene—PP, Polystyrene—PS, and Ethylene Vinyl Acetate—EVA). Three independent 21-day field experiments were conducted, and plastisphere development was assessed using multiple complementary approaches, including biomass (weight), bacterial density, photosynthetic pigment composition, macrofouling abundance, and DNA metabarcoding of bacterial (16S rRNA) and fungal (ITS) communities. Plastisphere development consistently followed the flooding gradient, with higher biomass, microbial density, and photosynthetic pigment concentrations in flooded and intermediate zones compared to the dry zone. Smaller plastic substrates favored microbial colonization, whereas larger substrates supported higher macrofouling abundance. Polymer color and type modulated colonization patterns of specific taxa, with EVA substrates showing higher biofilm accumulation. Community-level analyses revealed that flooding regime was the driver structuring bacterial and fungal community composition, with higher richness, diversity, and evenness in the intermediate zone. Differences among zones were driven mainly by shifts in the relative abundance of shared taxa rather than taxonomic turnover. Overall, this study demonstrates that environmental context, particularly flooding regime, outweighs plastic characteristics in shaping plastisphere communities in salt marshes, providing new insights into plastisphere dynamics in understudied Neotropical estuarine ecosystems.

Acinetobacter baumannii (A. baumannii) is recognized as an ESKAPE pathogen and a major cause of nosocomial infections. Despite advances in understanding the pathogenesis of A. baumannii and host immune responses, the direct interactions between A. baumannii and immune cells, as well as their influence on bacterial behavior, remain poorly defined. To address this gap, the present study established an in vitro model by co-culturing A. baumannii with human peripheral blood mononuclear cells (PBMCs) to investigate these interactions. A. baumannii isolated from patients’ pneumonia samples was co-cultured with PBMCs and their cell-free supernatants. After 24 h, the proliferation and viability of PBMC, the CFU count of bacteria, the PBMC cytokine profile, immune evasion gene expression (bap and ompA), biofilm formation, and bacterial motility were investigated. Co-culture with A. baumannii has significantly reduced the proliferation and viability of PBMCs compared with PBMCs alone. No significant change in bacterial CFU was observed in the co-culture group and cell-free supernatant. Cytokine analysis revealed a marked increase in TNF-α, whereas the production of IL-6 and IL-10 decreased in the co-cultured groups. Gene expression analysis revealed significant downregulation of bap in interaction with PBMC, whereas ompA expression remained unchanged. Co-culturing bacteria with PBMC resulted in an increase in biofilm formation; however, this difference was not statistically significant. Furthermore, there was no significant difference in surface-associated motility and twitching motility in the co-culture and bacterial alone groups. Overall, this is the first study to show direct interaction of A. baumannii and human PBMCs. The findings indicate that A. baumannii impairs the proliferation and viability of immune cells, while simultaneously resisting immune-mediated clearance. Interestingly, the downregulation of the biofilm-associated bap gene and the inflammatory microenvironment did not lead to significant changes in bacterial growth, biofilm formation, or motility. These findings demonstrate the robust resistance of A. baumannii to human immune defenses, underscoring the challenges in controlling and treating infections caused by this pathogen.

Carbon dioxide (CO₂) constitutes approximately two-thirds of total anthropogenic greenhouse gas emissions and therefore represents the primary target for mitigation strategies. Among the available approaches, algal-based CO₂ capture has emerged as a promising biological option due to the high photosynthetic efficiency, rapid growth rates, and capacity of microalgae to utilize concentrated CO₂ streams directly from industrial point sources. Under optimized laboratory and pilot-scale conditions, algal systems have been reported to achieve CO₂ fixation rates in the range of approximately 0.1–1.5 g CO₂ L^–1 d^–1, corresponding to areal biomass productivities of roughly 10–40 g m^–2 d^–1, depending on species, reactor configuration, and environmental conditions. This review critically evaluates the potential of algal-based systems for CO₂ biofixation, with particular emphasis on algal carbon assimilation mechanisms, cultivation strategies, and operational constraints relevant to large-scale deployment. Key parameters influencing CO₂ capture efficiency, including light irradiance, pH, nutrient availability, and gas–liquid mass transfer are systematically discussed. The role of algal–bacterial consortia in enhancing carbon utilization and enabling integration with wastewater treatment processes is also examined. Furthermore, the review compares open and closed cultivation systems, highlighting trade-offs among productivity, energy demand, contamination risk, and economic feasibility. While emerging approaches such as hybrid cultivation concepts and process-intensification strategies offer pathways to improve system performance, their practical implementation remains constrained by downstream processing costs and scale-up challenges. Overall, the analysis suggests that algal-based CO₂ mitigation is most effective when deployed as part of integrated biorefinery frameworks, particularly in conjunction with wastewater treatment and value-added biomass utilization—rather than as a standalone carbon sequestration solution. This integrated perspective provides a balanced assessment of the opportunities and limitations of algae-based CO₂ mitigation within sustainable climate and environmental management strategies.

The adhesion of bacterial cells through extracellular matrices plays a critical role in biofilm formation. Disrupting these matrices offers a promising strategy to overcome the persistent challenge of eradicating biofilms associated with chronic infections. CsgA, a major functional amyloid within the extracellular matrix of Escherichia coli (E. coli), adopts a β-sheet-rich conformation that contributes to the structural integrity of biofilms. The stability of these β-sheets is maintained by an extensive hydrogen-bonding network within the protein, and their disruption can compromise biofilm viability. In this study, computational approaches were employed to identify anti-biofilm peptides capable of targeting the β-sheet structures of CsgA amyloid. Among 41 screened peptides, 10 were predicted to be toxic, and the remaining 31 were subjected to molecular docking and reactivity analyses. The HOMO–LUMO energy gap was evaluated before and after docking to assess peptide reactivity, identifying 22 peptides with high reactivity for further dynamic simulations using discrete molecular dynamics. Comparative analyses revealed that Brevinin-1BW, Kassinatuerin-3, Ranateurin-2Awa, Temporin-B, and Magainin-I-KL decreased the β-sheet content of CsgA relative to the untreated protein. Notably, Magainin-I-KL induced a 7% reduction in β-sheet content and substantial structural disruption, as evidenced by decreased hydrogen bonding, increased metastable states in the free-energy landscape, and deformation patterns in cross-correlation analysis. Steered molecular dynamics simulations further demonstrated that Magainin-I-KL exhibited greater resistance to force-induced dissociation, indicating stronger interactions with CsgA. Overall, Magainin-I-KL effectively destabilizes the CsgA amyloid structure of E. coli, suggesting its potential as a lead peptide for disrupting amyloid-based biofilm formation and enhancing antimicrobial strategies.