Journal of Basic Microbiology最新文献

The ash weevil, Myllocerus subfasciatus, is a significant insect pest that infests brinjal. Both the adults and grubs feed on the leaves and roots, respectively, leading to considerable yield loss. The subterranean habits of the larvae limit the effectiveness of insecticide applications, necessitating the implementation of integrated pest management programs that utilize entomopathogenic fungi. This investigation aimed to identify potential Metarhizium species against ash weevil larvae through scanning electron microscopy (SEM) and histopathology. The ash weevils were mass-cultured on brinjal plants under insect-proof conditions. Eleven Metarhizium sourced from the departmental repository were subjected to pathogenicity tests on second-instar ash weevil larvae, revealing that a concentration of 1 × 10⁶ conidia/mL was optimal for SEM and histological studies. Among the 11 Metarhizium strains examined, the TNAU ENTMA TDM 8 strain produced spores measuring 5.8 µm in length and 2.4 µm in width in both potato dextrose agar (PDA) medium and larvae. SEM analysis indicated that the mycelial adherence and penetration of Metarhizium were most pronounced in the larvae 5 days post inoculation (DPI). Histopathological investigations demonstrated that the TNAU ENTMA TDM 8 strain caused degradation of fat bodies and hemocytes at 3 DPI, and complete body distortion at 7 DPI, while the untreated control exhibited no such effects. The M. robertsii strain TNAU ENTMR GYU 1 displayed slower infectivity compared to the M. anisopliae strains. The TNAU ENTMA TDM 8 strain was determined to be the most effective against M. subfasciatus larvae and can be utilized for managing ash weevil populations.

Subsidence from coal mining is a major environmental issue, causing significant damage to soil structure. Soil microorganisms, highly sensitive to environmental changes, adapt accordingly. This study focused on four areas of the Burdai coal mine: a non-subsidence area (CK), half-yearly (HY), 1-year (OY), and 2-year (TY) subsidence areas. Using high-throughput sequencing and molecular ecological network analysis, we examined soil microbial community diversity and structure across these zones, exploring microbial community assembly and functional predictions. Results showed that compared to the control, subsidence areas experienced reduced soil water content, organic matter, available phosphorus, and alkaline nitrogen, with the lowest levels observed at 1 year. These values began to rise after 1 year, suggesting natural recovery after subsidence stabilized. Microbial communities were closely related to soil organic matter, water content, and alkaline nitrogen. At the 1-year mark, soil property changes significantly reduced microbial diversity, which then began to recover after 2 years. The microbial network during 1-year subsidence was simpler, with 102 nodes, 179 edges, and an average degree of 3.51, indicating that early subsidence was unstable, and the microbial community was still adapting. By 1 year, community structure and interactions had begun to stabilize. Stochastic processes played a key role in microbial variability during short-term subsidence.

Non-steroidal anti-inflammatory drugs (NSAIDs) are emerging contaminants that pose significant health and environmental risks due to their persistence, including their presence in drinking water. Bioremediation, particularly through microorganisms such as actinobacteria, offers a sustainable approach to mitigate these pollutants. Actinobacteria from poly-extreme environments exhibit unique genetic and metabolic adaptations, enabling resistance to and degradation of various contaminants. This study aimed to evaluate the tolerance of actinobacteria to NSAIDs and conduct a genomic analysis of a selected strain. Actinobacteria were isolated from the crater of the Chichonal volcano [Chiapas, Mexico), resulting in 16 isolates. Among these, Micrococcus luteus P8SUE1, Micrococcus yunnanensis P9AGU1, and Kocuria rhizophila P1AGU3 demonstrated tolerance to diclofenac, ibuprofen, and paracetamol at concentrations of 1 ppm, 10 ppm, and 100 ppm, respectively. Whole-genome sequencing of M. yunnanensis P9AGU1 identified genes linked to the degradation of aromatic compounds and adaptations to extreme environmental conditions, highlighting its potential for bioremediation applications.

Metacaspases (MCA), are cysteine-dependent proteases closely related to caspases. In protozoa, MCA plays an important role in programmed cell death (PCD). In Trichomonas vaginalis, a kind of PCD that resembles apoptosis has been described, but the activators of this mechanism have not been demonstrated. We performed a genome-wide in silico analysis in the T. vaginalis database using consensus MCA domains. A total of 15 protein annotations for MCA-like sequences were retrieved. Only 7/15 (TvMCA1-6 and TvMCA9) of the sequences were annotated as putative MCA and exhibited a similar range of amino acid length in comparison to the consensus sequences used for the query. By in silico analysis, we found that they are thermostable, hydrophilic proteins with molecular weights ranging from 27 to 33 KDa and their theoretical isoelectric points are in a 5.08-8.57 range. The phylogenetic analysis showed the similarity of conserved motifs for the predicted TvMCA proteins. 3D structure prediction by homology modeling demonstrated that TvMCA proteins show a similar conformation to crystallized MCA proteins. Taken together, our results indicate that these trichomonad proteins have conserved sequences like MCA proteins and suggest that they may be responsible for proteolytic activity during a PCD-like mechanism in this parasite.

Soil-borne plant pathogens are the most damaging pathogens responsible for severe crop damage. A conventional chemotherapy approach to these pathogens has numerous environmental issues, while biological control agents (BCAs) are less promising under field conditions. There is an immediate need to develop an integrated strategy for utilizing nanoparticles and biocontrol to manage soil-borne pathogens, such as Fusarium wilt, effectively. Simulation of BCA metabolites to nanoparticle biocontrol metabolites is considered the most effective biocontrol approach. Combining Fe₂O₃ nanoparticles and Trichoderma in nursery and field conditions manages pathogens and increases plant growth characteristics. The present study evaluated the commercial biocontrol strains and the use of NPFe in combination with Trichoderma harzianum to enhance the biocontrol potential of T. harzianum against soil-borne pathogens. The effectiveness of (NPFe + T. harzianum) was evaluated under in vitro conditions where combination was found most effective upto (87.63%) mycelial growth inhibition of pathogen and under field conditions lowest pooled Fusarium wilt incidence (19.54%) was recorded. Nanocomposites are beneficial for agricultural sustainability and environmental safety by upregulating the expression of genes linked to these processes, Fe NPs can activate plant defense mechanisms and increase plant resistance to pathogenic invasions. Additionally, as iron is a necessary component for plant growth and development, Fe NPs promote better nutrient uptake.

Acinetobacter has been recognized as a versatile plant growth promoting (PGP) rhizobacteria (PGPR) that produce multiple PGP traits. The present study was conducted to formulate an efficient and stable liquid bacterial inoculant (LBI) of Acinetobacter lwoffii strain PAU_31LN. In the current investigation, total 16 endophytic bacteria were isolated from cotton leaves and evaluated for plant growth-promoting features such as production of phytohormones, mineral solubilization, siderophore production, hydrogen cyanide (HCN) production, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. The leaf endophytic bacteria designated as 31LN was found promising for all the PGP traits and it was identified as A. lwoffii strain PAU_31LN by 16S rRNA gene sequencing. For the development of LBI of A. lwoffii strain PAU_31LN, 4.5 g/L yeast extract, 5 g/L NaCl, 5 g/L peptone, and 12.5 mM food-grade trehalose was optimized as appropriate medium composition using response surface methodology (RSM) and Box-Behnken design. Further, the viability of A. lwoffii strain PAU_31LN in the optimized formulation was observed as 1.1 folds higher over the control after 180 days of storage at room temperature. Moreover, nonsignificant variation was recorded in the functional traits of 180 days old LBI of A. lwoffii strain PAU_31LN and freshly prepared LBI. The in-vitro plant growth parameters such as length and seed vigor index of 7-day-old cotton seedlings were enhanced by the seed bio-priming with LBI of A. lwoffii strain PAU_31LN over the control. The results of the present study signify the importance of endophytes and statistical methods to formulate prominent LBI.

One of the main difficulties in nanotechnology is the development of an environmentally friendly, successful method of producing nanoparticles from biological sources. Silver-doped zinc oxide nanoparticles (Ag-ZnO NPs), with antibacterial and antioxidant properties, were produced using Adiantum venustum extract as a green technique. Fresh A. venustum plants were gathered, then their bioactive elements were extracted with cold water and processed into nanoparticles. The main goal was to develop Ag-ZnO NPs (nanoparticles) for medical applications, especially with regard to their antifungal and antibacterial properties. Pathogens such as Fusarium oxysporum, Escherichia coli, and Staphylococcus aureus were tested against the synthesized nanoparticles. While FTIR spectroscopy revealed functional groups, X-ray diffraction validated the crystalline structure. The scanning electron microscope analysis revealed that the Ag-ZnO NPs had an average size of 30.16 nm and an irregular shape. Additionally, energy dispersive X-ray analysis) confirmed the elemental composition. The bioactive compounds present in A. venustum significantly stabilized the nanoparticles. Strong antioxidant and antibacterial activity of the Ag-ZnO nanoparticles was demonstrated. In particular, this work shows that the Ag-ZnO nanoparticles produced by green synthesis could be used in biomedical drug delivery and therapy.

Recently, the biosynthesis of omega-3 fatty acids (ω3 FAs) in yeast has witnessed significant advancements. Notably, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play crucial roles in overall human growth, encompassing neurological development, cardiovascular health, and immune function. However, traditional sources of ω3 FAs face limitations such as environmental concerns. Yeast, as a genetically tractable organism, offers a promising alternative for its sustainable production. Recent advancements and strategies in yeast through metabolic engineering led to significant improvements in ω3 FA production, including the optimization of metabolic pathways, enhancement of precursor supplies, and manipulation of gene expression. Moreover, innovative bioprocess approaches, such as fermentation conditions and bioreactor design, have been devised to further maximize its yields. This review aims to comprehensively summarize recent strategies in ω3 FA production within yeast systems, highlighting their contribution to meeting global ω3 FA demand while mitigating environmental impact and ensuring food security.