Journal of Basic Microbiology最新文献

Cover illustration:

Free-living amoebae of the genus Acanthamoeba produce new antibacterial agents to fight pathogenic bacteria. The antibacterial effect of cell-free supernatants obtained from the depicted Acanthamoeba against some pathogenic bacteria were tested against the control strain Acanthamoeba castellanii ATCC 50373.

(Photo: Şevval Maral Özcan Aykol, Department of Pharmaceutical Microbiology, Biruni University Faculty of Pharmacy, Istanbul, Turkey)

Saffron (Crocus Sativus L.) is a highly prized spice crop renowned for its significant culinary and therapeutic applications, largely attributed to its bioactive constituents such as crocin, picrocrocin, and safranal. Despite its production is severely threatened by corm rot, particularly caused by the pathogenic fungus Fusarium oxysporum, which leads to substantial yield losses in major saffron-producing regions. This review highlights the promising role of microbial consortia as an eco-friendly and sustainable strategy for effectively managing corm rot disease. The presence of diverse microbial communities can improve defense mechanisms of a plant against pathogens and support its overall growth and productivity. The mechanisms by which these microbial interactions occur, including nutrient competition, biofilm formation, and the activation of systemic resistance, contribute to their combined efficacy in inhibiting fungal pathogens. The necessity for innovative microbial strategies that harness the combined benefits of diverse microorganisms to mitigate corm rot and improve saffron cultivation sustainably. As sustainable agricultural practices increasingly gain prominence, the development and application of tailored microbial consortia gave a promising alternative to chemical fungicides, ensuring both economic viability and ecological balance in saffron production.

Pests and diseases have a significant impact on crop health and yields, posing a serious threat to global agriculture. Effective management strategies, such as integrated pest management (IPM), including crop rotation, use of synthetic pesticides, biological control, and resistant/tolerant crop varieties, are essential to mitigate these risks and ensure sustainable agricultural practices. Fungal bioagents play an important role in managing phytopathogens and insect pests by acting as biological agents. They promote healthy plant growth by enhancing the uptake of nutrients and combating systemic resistance in plants. Furthermore, fungal bioagents are environmentally friendly, reducing application of fungicides and insecticides and minimizing their negative impact on the crops and environment. Their use in IPM promotes sustainable agriculture and ensures high-quality crops while maintaining soil health and microbial biodiversity. These fungal bioagents are rich sources of volatile organic compounds (VOCs), which play an important role in biological communication during interaction with insect pests and phytopathogens. In pest management, VOC production by beneficial fungi is accountable for their efficacy against pests and pathogens. Thus, this review discusses the important fungal bioagents producing VOCs, extraction methods of VOC, and the use of VOC-producing fungi in pest and disease management, knowledge gaps, and future research areas.

Understanding bacterial genetics and metabolism is vital for developing biopesticides. This study investigates Bacillus subtilis NBAIR-BSWG1, a strain well known for its antagonistic potential. Crude lipopeptides extracted from the strain were evaluated for in vitro activity, showing complete inhibition of Rhizoctonia solani at a concentration of 50 μL/mL potato dextrose agar. To delve deeper into its antagonistic mechanisms, we conducted whole-genome sequencing of NBAIR-BSWG1 using Illumina NextSeq 500. Subsequent analysis with the BlastX diamond tool revealed 19 key biosurfactant genes, including surfactin (srfAA, srfAC, srfAD, srfP), fengycin (ppsE, ppsD, ppsC, ppsB), and putisolvin (dnaK), which were further confirmed by PCR using specific primers. Meanwhile, antiSMASH analysis revealed gene clusters with 100% similarity to those responsible for the synthesis of fengycin, bacilaene, bacillibactin, subtilosin A, and bacilysin, as well as clusters with 82% similarity to surfactin synthesis genes. Additionally, liquid chromatography-mass spectrometry was performed to analyze the cell-free extract produced by NBAIR-BSWG1, revealing the presence of various cyclic lipopeptides, including multiple peaks corresponding to surfactin, iturin, and several novel lipopeptide compounds. This study highlights B. subtilis NBAIR-BSWG1 cyclic lipopeptides as a key to broad-spectrum bio-control and establishes the strain as highly potent.

Pseudomonas aeruginosa is an opportunistic bacterium widely distributed in both natural and urban environments, playing a crucial role in global microbial ecology. This article reviews the interactive dynamics of P. aeruginosa across different ecosystems, highlighting its capacity for adaptation and resistance in response to environmental and therapeutic pressures. We analyze the mechanisms of antibiotic resistance, including the presence of resistance genes and efflux systems, which contribute to its persistence in both clinical and nonclinical settings. The interconnection between human, animal, and environmental health, within the context of the One Health concept, is discussed, emphasizing the importance of monitoring and sustainable management practices to mitigate the spread of resistance. Through a holistic approach, this work offers insights into the influence of P. aeruginosa on public health and biodiversity.

Two polyhydroxyalkanoate synthase genes, phaC1 and phaC2, were identified in three strains of Cupriavidus malaysiensis (C. malaysiensis): C. malaysiensis USMAA1020^T, C. malaysiensis USMAHM13, and C. malaysiensis USMAA2-4. Interestingly, the genome of C. malaysiensis USMAA1020^T revealed the presence of the polyhydroxyalkanoate granule-associated protein (phaF), which was not present in C. malaysiensis USMAHM13 and C. malaysiensis USMAA2-4. A Maximum Likelihood phylogenetic analysis shows that the phaC genes were classified into Class I synthases. The phaC1 and phaC2 genes in the three C. malaysiensis strains formed a separate, distinct cluster. To further examine the function of phaC, both phaC genes were cloned from C. malaysiensis USMAA1020^T and individually expressed in Cupriavidus necator (C. necator) PHB-4, which serves as a benchmark of functionality for other strains. Using γ-butyrolactone as the sole carbon source, the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) contains up to 83.00 mol% 4-hydroxybutyrate (4HB) and 26.50% PHA content. However, the transformant C. necator PHB-4 with phaC2 produced only 2.30% PHA content and no 4HB monomer. The phaC2 transformant produces up to 100 mol% 3HB monomer and 41.90% PHA content, while the phaC1 transformant produces only 25.80% PHA content when using oleic acid as the sole carbon source. When provided with a mixed substrate of oleic acid and 1-pentanol, the transconjugants accumulated up to 20% PHA content but produced a low 3HV content of only 4%-5%. These findings significantly contribute to the scientific literature by improving the understanding of the genetic and biochemical diversity of the two PHA synthases, phaC1 and phaC2, in Cupriavidus species.

Gemfibrozil (GEM) is a phenoxy aromatic acid-based lipid-lowering drug. It activates peroxisome proliferator-activated receptor alpha (PPAR-α), which leads to altered lipid metabolism and lowers serum triglyceride levels by modulating lipoprotein lipase. However, the action of the mode of GEM is still unclear. Herein, the model organism Saccharomyces cerevisiae was applied to explore the molecular mechanism of GEM regulating lipid metabolism. The results showed that the triacylglycerol (TAG) content and the number of lipid droplets of yeast increased significantly after GEM treatment in the wild-type BY4741. Screening of mutations related to lipid metabolism pathways (PAH1, DGK1, TGL3, TGL4, LRO1, ARE1, ARE2, and DGA1) showed that dgk1Δ had no change in lipid accumulation under GEM. In the wild type, GEM inhibited the expression of DGK1, resulting in a significant decrease in the contents of phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS)) and neutral lipids (TAG and diacylglycerol (DAG)). However, their abundances could not be changed in dgk1Δ after the treatment with GEM Luciferase assay further showed that DGK1 may be a target of GEM to induce lipid accumulation via TUP1/CYC8, which could act on the DGK1 promoter-TATA highly conserved element (-400 bp - 200 bp). Altogether, the effect of GEM on lipid metabolism was associated with the upregulation of TUP1/CYC8, leading to a decrease in the expression of DGK1, thereby increasing the TAG content in yeast cells. It is expected that the data will help to clarify the molecular mechanism of GEM regulating lipid metabolism in humans.

Cover illustration:

Actinomycetes isolated from a metal rich environment in a former uranium mining area near Ronneburg, Thuringia. The strains show high metal resistance.

(Photo: Götz Haferburg, Friedrich-Schiller-University, Jena, Germany)