Current Microbiology最新文献

In forest nurseries, maintaining plant health is essential for producing high-quality seedlings. Effective sanitary management relies on continuous monitoring throughout the crop cycle. Powdery mildew, caused by fungi in the Erysiphaceae family, extracts nutritional plant reserves, thus reducing its productive potential and causing significant economic losses due to lower yield and quality. Although Erysiphaceae has not been yet studied in some natural ecosystems, such as the Chaco region of Argentina, information from these natural ecosystems is critical. This research aimed to comprehensively study Pleochaeta prosopidis isolates from Neltuma alba and to assess the relationship between disease incidence and seedling quality in nursery conditions. This pathogen exhibited a partially endoparasitic life cycle, causing damage to the mesophyll of infected leaves. The phylogenetic analysis of the 28S rDNA sequences from N. alba seedlings with powdery mildew signs grouped with the reference sequence corresponding to Pl. prosopidis. The highest levels of disease incidence and severity occurred during winter and in plants kept in the nursery for over nine months (p < 0.001). Infected seedlings showed a significant reduction in height and diameter at neck height (p < 0.007), indicating a clear decline in quality. This study provides the first comprehensive description of Pl. prosopidis in N. alba, highlighting its impact on seedling development and nursery productivity.

A Gram-stain-negative, aerobic and triclosan-degrading strain W03^T, was isolated from the wastewater treatment plant (WWTP) in the Macau peninsula (Macau SAR, China). Based on polyphasic taxonomic analyses, strain W03^T was identified as a novel species within the genus Pseudomonas. It grew optimally in Luria-Bertani medium at pH 7.0, with 1% (w/v) NaCl, and at 30℃. Strain W03^T demonstrated a high tolerance to NaCl, with the ability to withstand up to 7% (w/v) NaCl. This strain was characterized using 16S rRNA gene sequencing, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) along with physiological and biochemical tests. Phylogenetic analysis based on 16S rRNA gene and gyrB gene sequences revealed that strain W03^T is most closely related to Pseudomonas triclosanedens ZM23^T. The genome size of strain W03^T was 6.08 Mbp, with a genomic DNA G + C content of 65.1%. OrthoANI and dDDH values between strain W03^T and P. triclosanedens ZM23^T confirmed that they represent distinct species. Based on the phylogenetic, physiological, and biochemical characteristics, strain W03^T is identified as a novel species within the genus Pseudomonas, for which the name Pseudomonas macauensis sp. nov. is proposed.

Diverse tactics are employed to increase agricultural productivity in order to meet the growing food needs resulting from population growth. Using plant growth-promoting bacteria (PGPB) has proven to be a practical way to apply novel agricultural techniques. Although PGPR derived from rhizospheric soil has been extensively studied, more research on marine microorganisms is required. As marine environment is an extreme environment the marine bacteria is adapted to grow at extreme conditions which enables them to produce various secondary metabolites which can be useful in certain ways. The current study attempts to explore marine microorganisms' capacity to stimulate plant growth. The bacteria isolated form marine environment Microcella sp. strain 23 was found tolerating upto 13% of salinity. This bacterium is able to solubilize various essential minerals such as phosphate and potassium and able to produce ammonia and IAA (Indole-acetic acid), which makes it a possible plant growth promoter. The study was conducted on Pennisetum glaucum (Pearl Millet) crop and pot trials were performed with two groups, control (untreated) and treated with M23 (Microcella sp. coated seeds). Treated plants after 32 days of sowing showed increase in plant shoot length and root length by 48.33% and 29.88% respectively as compared to untreated plants. Microcella sp. M23 acts as plant growth promoter by solubilizing essential minerals, reflected in increased chlorophyll and carotenoid content along with stress markers by activating plants defense system that can protect plant from both biotic and abiotic stresses.

A bisphenol A degrading actinobacterium, strain A6^T, was isolated from a waste digestion system in Chaozhou, China. Cells of strain A6^T were Gram-stain-positive, aerobic, non-spore-forming, non-motile, rod-shaped, and forming yellow colonies on Reasoner's 2 A agar. Phylogenetic analyses based on the 16 S rRNA gene showed that strain A6^T shared 96.8% sequence similarity with Enemella dayhoffiae NML 130,396^T and formed a distinct lineage in the family Propionibacteriaceae in the phylogenetic trees. Genome-based phylogenetic analyses indicated that strain A6^T could be assigned as a novel genus in the family Propionibacteriaceae. The cellular components, including anteiso-C_15:0 (40.0%) as a predominant fatty acid, MK-9(H4) as the major respiratory quinone and a DNA G + C content of 67.2% supported strain A6^T as a member of the family Propionibacteriaceae. However, strain A6^T also contained C_11:0-3-OH (14.4%), iso-C_16:0 (11.3%), and C_11:0 (10.6%) as predominant fatty acids which distinguished it from other genera in the family Propionibacteriaceae. In addition, strain A6^T was negative in enzyme activity of esterase (C4), esterase lipase (C8), aminase of leucine, and negative in the utilization of most carbon sources, which were different from its close related genera in the family Propionibacteriaceae and supported it as a novel genus. Therefore, the name Pseudenemella bisphenolivorans gen. nov., sp. nov. is proposed. The type strain is A6^T (= GDMCC 1.3237^T =KCTC 92291^T).

Listeria monocytogenes (Lm) is a facultative intracellular pathogen responsible for life-threatening listeriosis, characterized by high mortality rates. Currently, there is no vaccine available for the prevention or treatment of listeriosis. Here, we developed two adjuvanted inactivated vaccines and evaluated their safety, immunogenicity, and protective efficacy. The hypervirulent Lm strain XYSN was inactivated with β-propiolactone (BPL) and formulated with AddaVax or Alum to produce inactivated vaccines (ADIV and ALIV) respectively. Local reactogenicity and histopathological observations revealed no adverse reactions in a murine model. Humoral assays demonstrated both ADIV and ALIV induced higher antibody titers against Lm XYSN, with ADIV eliciting stronger cellular immune responses, as indicated by increased IL-17 and IFN-γ expression in spleen cells. Notably, ADIV conferred 83.3% protection against a lethal challenge with hypervirulent Lm strain, representing a 50% increase compared with the 33.3% protection achieved by ALIV. AddaVax adjuvant not only augmented humoral responses to inactivated bacterial cells but also elicited stronger cellular immune responses compared to Alum adjuvants, resulting in enhanced immune protection. This research offers insights into developing novel inactivated vaccines for listeriosis prevention, particularly beneficial for immunocompromised individuals.

To enhance stability and antimicrobial efficacy of antimicrobial peptide (AMP) epinecidin-1, we previously engineered three variants - GK-epi-1, Variant-1 and Variant-2-by substituting alanine and histidine residues with lysine. Our current study focuses on the antifungal capabilities of Epinecidin-1 and its variants against the clinical isolates of Candida spp. (Candida albicans, C. tropicalis, C. krusei & C. glabrata) and Aspergillus flavus. Computational docking studies are evidenced, the peptides had strong affinity against all fungal receptor examined which indicates their efficacy to interact with the Candida cell membrane receptors (Exo-B-(1,3)-Glucanase, Secreted aspartic proteinase (SAP) 1 & N-terminal domain adhesin: Als 9 - 2). Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC) and antibiofilm assays revealed its potent antifungal activity, particularly in disrupting biofilm formation. Effects of peptides on hyphal growth inhibition activity and Scanning Electron Microscopy (SEM) confirmed that the mechanism of action involves pore formation, hyphal disruption and induction of reactive oxygen species in Candida cell membrane. The antifungal spectrum was extended to A. flavus, a known ocular pathogen, where combination therapy using sub-inhibitory concentrations of Epinecidin-1 and its variant peptides with Amphotericin B and Miconazole showed enhanced synergistic effects, reducing required dosages for effective pathogen control.

Oil contamination poses serious environmental challenges, particularly in hyper-arid desert ecosystems; yet, microbial responses to oil pollution and biostimulation in desert soils remain insufficiently explored. This study explored the microbial community dynamics and hydrocarbon degradation potential to oil contamination and biostimulation in desert soils collected from sites in southern Israel polluted in 1975 and 2014. Laboratory-based biostimulation experiments were conducted over 1.5 years, involving the addition of water (20% or 50% gravimetric saturation), nutrients, and biosurfactants. Results revealed that biostimulation treatments reduced microbial diversity but enriched populations capable of hydrocarbon degradation. Proteobacteria and Actinobacteria were the dominant phyla, comprising 68% to 78% of the total microbial community across both contamination timelines. The relative abundance of Chloroflexi was higher in biostimulated contaminated soils, showing an increase of 41% to 227% compared to untreated contaminated soils. Differential abundance analysis identified distinct taxa of hydrocarbon degraders associated with untreated contaminated soils (e.g., Pseudomonas, Alkanindiges, Bacillus, and Mycobacterium) and biostimulated contaminated soils (e.g., Pseudomonas, Flavobacterium, Pseudoxanthomonas, unclassified Microbacteriaceae, Solimonadaceae, and Gammaproteobacteria). Further, soil hydrophobicity and total petroleum hydrocarbon suggested a positive relationship with the abundance of the nahAc gene, a key marker of hydrocarbon degradation. These findings exhibit that targeted biostimulation with water, nutrients, and biosurfactants accelerates oil biodegradation while selectively reshaping microbial communities toward hydrocarbon degrading taxa in hyper-arid desert soils. This study points to the potential development of effective management and remediation strategies for oil-contaminated desert environments.