Current Microbiology最新文献

Passiflora edulis (P. edulis Sims) is prevalent in tropical regions, and its distinctive taste and aroma are highly appreciated due to its unique nutritional profile. With the increasing recognition of the added value of P. edulis Sims wine, an expanding number of researchers have begun to focus on the related studies concerning the brewing process of this wine. Isolating high-quality yeast strains from the natural fermentation broth of P. edulis Sims is crucial for this purpose. In this study, 38 yeast strains were isolated and purified from the fermentation broth of P. edulis Sims. Nine yeast strains were selected using WL medium for further analysis. The fermentation characteristics of these strains were evaluated based on their production of esters, ethanol, and hydrogen sulfide (H₂S), as well as through tolerance tests. The results indicated that the nine yeast strains exhibited favorable fermentation performance characterized by low H₂S production while demonstrating high levels of ester and ethanol production, along with certain antimicrobial activity. Among these strains, GZH-20 displayed a notably low capacity for H₂S production coupled with exceptional abilities in both ester and ethanol generation. Furthermore, this strain demonstrated good tolerance under various conditions, including pH levels ranging from 2.8 to 3.8, a glucose concentration of 200 g/L, and varying sulfur dioxide (SO₂) concentrations between 60 g/L and 360 g/L; it showed superior capacities for producing esters and ethanol under these conditions. Molecular identification confirmed that this strain is classified as Wickerhamomyces anomalus. These findings hold significant implications for advancing our understanding of specialized yeasts involved in P. edulis Sims wine production.

Bacteriophytochrome-derived near-infrared fluorescent proteins (NIR FPs) provide deep tissue penetration, low autofluorescence, and endogenous biliverdin compatibility, enabling non-invasive visualization of viral processes in living systems. Engineering advances (iRFPs, monomeric miRFPs, photoactivatable PAiRFPs) have improved brightness, stability, and genetic encodability for robust use in mammalian models. These reporters support real-time tracking of infection dynamics and host-virus interactions and power diagnostic platforms including reporter viruses, CRISPR-based assays, and nanotechnology-enhanced biosensors. Multimodal integration with photoacoustic tomography and PET further extends their translational utility. Remaining challenges include brightness/photostability limits and the need for broader translational validation, yet progress in structure-guided mutagenesis, computational/AI-assisted protein design, and hybrid imaging strategies promises to close these gaps. This mini-review synthesizes the design principles, viral imaging/detection use cases, and translational prospects of bacteriophytochrome-derived NIR FPs, highlighting their potential to advance viral surveillance, therapeutic evaluation, and precision diagnostics.

The virus communities of inland aquatic ecosystems have typically received less attention from the research perspective than those of marine ecosystems. In this study, we compared the viromes of an estuarine creek (Santana Creek) belonging to the khazan ecosystem and an agriculturally relevant freshwater lake (Verna Lake), both located in Goa, India. Taxonomically, the viral realm Duplodnaviria predominated in both the lake and creek communities, Varidnaviria had a minor presence in both, and Monodnaviria was exclusively present in the lake community. Sequences identified in the creek virome bore a greater resemblance to those of marine ecosystems than those in the lake virome. Functional annotation confirmed the taxonomic findings, indicating most proteins were involved in the infective and replicative functions of bacteriophages. Predicted complete viral genomes included those of Synechococcus and Proteus phages in the creek dataset, and of Gokushovirinae phages in the lake dataset. Viral communities of the khazan ecosystem and similar ecosystems worldwide are understudied, and hence the present virome analysis offers a valuable reference for further studies on these ecosystems.

Widespread chemical pesticide use in agriculture threatens environmental and human health, creating urgent demand for sustainable alternatives like entomopathogenic fungi. However, effective entomopathogenic fungi for Protaetia brevitarsis remain scarce. This study first isolated and identified the Aspergillus aculeatus strain JBQM-1 from naturally infected P. brevitarsis larvae. Its identity was confirmed via morphological analysis, ITS rDNA sequencing, and calmodulin gene phylogeny. The calmodulin gene was used to address the limitation of ITS alone in distinguishing closely related Aspergillus species, ensuring accurate identification. JBQM-1 spores showed time-dependent germination in potato dextrose broth(PDB)medium, reaching 96.75% by 8 h. This rapid germination is key to timely host infection, supporting its biocontrol potential. Pathogenicity assays revealed JBQM-1's dose- and time-dependent virulence: 71% larval mortality at 1.0 × 10⁹ conidia per milliliter by day 7, with no mortality in the first 48 h. A heat-inactivated control assay was conducted to rule out non-infectious factors. The heat-inactivated group had 6.67 ± 3.34% mortality, which was not statistically different from the control group's 4.44 ± 1.92% mortality. No hyphal outgrowth was observed on dead larvae from the heat-inactivated group after 72 h incubation in moist chambers. This confirms JBQM-1's high virulence, expands A. aculeatus' host range, and highlights its potential as a biocontrol agent, providing new microbial resources for sustainable pest control.

The present study investigates the antibacterial potential of fatty acid methyl esters (FAMEs) from the cyanobacterial species Neowestiellopsis persica, isolated from Meghalaya, a north-eastern state in India. Given the growing threat of antibiotic resistance, this study explores an alternative source of bioactive compounds from cyanobacteria to combat bacterial pathogens such as Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. The cyanobacterial species Neowestiellopsis persica was cultured under controlled laboratory conditions, followed by the extraction of fatty acid methyl esters (FAMEs). The extract was then screened for antimicrobial activity using Kirby-Bauer disc diffusion assays, demonstrating significant inhibition of bacterial growth, particularly against Staphylococcus aureus with a zone of inhibition of 22 ± 1 mm. Minimum inhibitory concentration (MIC) tests further supported the antibacterial efficacy of the extract with Staphylococcus aureus and Klebsiella pneumoniae exhibiting the lowest minimum inhibitory concentrations of 2.5 ± 0 mg/mL. Gas chromatography-mass spectrometry (GC-MS) analysis identified four key bioactive compounds which were subsequently evaluated through in silico molecular docking studies. The docking results revealed promising interactions between the bioactive compounds notably heptacosanoic acid, 25-methyl,-methyl ester with PBP2a protein of Staphylococcus aureus with the lowest binding energy of -6.49 ± 0.560 kcal/mol, suggesting potential for developing new antimicrobial agents. Additionally, the drug-likeness and toxicity of the compounds were assessed using in silico tools, supporting the potential for these compounds as viable candidates for future antibacterial drug development.

Magnesium is an essential mineral involved in more than 300 enzymatic reactions, including protein synthesis, neuromuscular function, and blood pressure regulation. Recent studies have highlighted the role of probiotics, beneficial microorganisms in the human gut, in enhancing mineral absorption. However, the interaction between magnesium and probiotic strains remains poorly understood. This study aimed to investigate the capacity of Lacticaseibacillus rhamnosus ATCC 53,103 to uptake and internalize magnesium ions, using MgSO₄ as a supplementation source. The bacterium was cultivated in MRS medium with varying concentrations of MgSO₄ (0, 0.1444, 0.722, and 1.444 g/L) over seven days. Quantitative analysis revealed that at 0.722 g/L MgSO₄, intracellular magnesium accumulation peaked at 0.7 mg/dL by Day 3, representing a 7-fold increase compared to the control (0.1 mg/dL). Scanning and transmission electron microscopy indicated essential morphological changes, including ruffled cell surfaces and enhanced ribosomal visibility. These findings suggest that L. rhamnosus can internalize magnesium under enriched conditions, supporting its potential as a microbial carrier for nutribiotic applications. This work contributes to the growing field of mineral-microbe interactions and may inform the development of probiotic-based strategies to improve magnesium bioaccessibility in the human gut.