Journal of microbiology and biotechnology最新文献

Considering the dangerous effects on the environment of commonly used packaging materials like low-density polyethylene (LDPE), finding a practical and environmentally safe method for decomposing plastics is crucial. In this study, a bacterial strain (HMBC3) was identified in plastic-contaminated soil samples from eastern Saudi Arabia and showed potential for breaking down LDPE, as revealed by results from weight loss, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and gas chromatography-mass spectrometry (GC-MS). HMBC3 was discovered among bacterial isolates in a mineral nutritional medium (MNM) enhanced with LDPE as the only carbon and energy source. The strain caused changes in the media pH from 7.0 ± 0.03 to 6.23 ± 0.05, while the LDPE also showed 20.4% weight loss. In addition, the 16S rRNA gene similarities revealed a 98.9% homology between HMBC3 and Cytobacillus sp., indicating their close similarity. The high efficiency of strain HMBC3 in biodegrading plastic could potentially lead to its widespread development as an eco-friendly way to eliminate or minimize environmental plastic pollution.

A Gram-stain-negative, facultative anaerobic rods, designated as strain 219JJ12-13^T, was isolated from a marine sponge, Poecillastra wondoensis, in Jeju-do, Republic of Korea. The cells displayed catalase and oxidase activity and were non-motile. Strain 219JJ12-13^T grew at 10-37°C (optimum, 25-30°C), pH 6.0-8.5 (optimum, pH 7.0-7.5), and in the presence of 0.5-6.0% (w/v) NaCl (optimum, 4.0-5.0%). The polar lipids comprised disphosphatidylglycerol, phosphatidylglycerol, phosphatidylcoline, phosphatidylethanolamine, sphingoglycolipid, two aminophosphoglycolipid, unidentified phospholipid, and two unidentified lipids. The isoprenoid quinone was identified as Q-10, and predominant cellular fatty acids were C_17:1 ω6c, summed feature 3 (C_16:1 ω7c/C_16:1 ω6c), and summed feature 8 (C_16:1 ω7c/C18:1 ω6c). The G+C content of the genomic DNA was 63.3%. The 16S rRNA gene and genome sequences-based phylogenetic analyses showed that strain 219JJ12-13^T formed a distinct phyletic clade within the genus Aurantiacibacter. Genome relatedness values, including average nucleotide identity and digital DNA-DNA hybridization among strain 219JJ12-13^T and closely related type strains, were 74.0-80.2% and 18.2-22.8%, respectively, both markedly below the thresholds for species delineation. Based on polyphasic taxonomic approach, strain 219JJ12-13^T represents a novel species of the genus Aurantiacibacter, and the name Aurantiacibacter poecillastricola sp. nov. is proposed. The type strain is 219JJ12-13^T (= KACC 23236^T = LMG 33060^T). The reclassification of Erythrobacter alti to the genus Aurantiacibacter as Aurantiacibacter alti comb. nov. is also proposed (= KCCM 90261^T = NBRC 111903^T).

We compared the salt tolerance and proteolytic activity of 120 strains of each of Bacillus subtilis, Bacillus velezensis, and Bacillus licheniformis. Most B. subtilis strains exhibited growth in 12% (w/v) NaCl and showed proteolytic activity in 10% or 11% NaCl. The majority of B. velezensis strains grew in 14% NaCl and showed proteolytic activity in 12% or 13% NaCl. Most B. licheniformis strains grew in 14% NaCl and exhibited proteolytic activity in 5%-7% NaCl. We selected nine representative strains of each species based on their proteolytic activities and analyzed the free amino acid (FAA) profiles produced by culture of the bacteria on soybean. Statistical analyses of the 22 FAAs quantified in the cultures revealed clustering of FAA production profiles at the species level. The FAA production profiles of B. subtilis and B. velezensis were similar, and both differed from that of B. licheniformis. These trends persisted in cultures containing 7% NaCl. These results suggest that FAA production profiles are characteristic of each Bacillus species. Specifically, in soybean cultures compared with uninoculated soybeans, B. subtilis increased the amounts of leucine and phenylalanine; B. velezensis increased the amounts of leucine, phenylalanine, and tyrosine; and B. licheniformis increased the amounts of alanine, glutamic acid, tyrosine, and ornithine, and dramatically decreased the amount of arginine. The proteolytic activity of B. velezensis strains correlated with the quantity of FAAs in their soybean cultures. Considering its salt tolerance and proteolytic activity, B. velezensis showed high potential for contributing to the ripening of high-salt fermented soybean foods. Our results regarding the specific production of amino acids at the species level and correlations between proteolytic activities and produced amino acid quantities will facilitate the determination and selection of target strains for functional Bacillus-fermented foods.

Delayed treatment of insomnia-related symptoms can harm physical health and increase the psychological burden. In addition to oral medications and some physical therapies, aromatherapy can help overcome some treatment-related side effects. Herein, parachlorophenylalanine (PCPA)-induced insomnia was established in Kunming (KM) mice, which were subjected to aromatherapy using five plants (Jasminum sambac, Magnolia denudata, Rosa rugosa, Aloysia citriodora, and Abies balsamea) essential oils (EOs). To determine the sleep-inducing effect of the five EOs, the rate of change in body weight, sleep latency, and total sleep time in mice were measured. Specific serum indices were used to evaluate the therapeutic effects of the tested drugs and PCPA modeling. Gas chromatography-mass spectrometry (GC-MS) was employed to identify active components in EOs. The five EOs contained multiple identical constituents and were rich in terpenoids, such as α-farnesene (28.42%), linalool (68.84%), and citronellol (23.78%). The EOs exhibiting varying effects on insomnia-induced weight loss. Nissl staining was used to examine and the number of neurons was elevated in the EO-treated groups when compared with the PCPA-induced group; however, the neuronal number was reduced in the hypothalamic tissues of the R. rugosa EO (RREO)-treated group. All EOs upregulated the expression of 5-HT1A and GABA_ARα1, as demonstrated by immunohistochemistry, western blotting, and reverse transcription-quantitative PCR results. In addition, EOs of A. citriodora and A. balsamea significantly upregulated the expression of 5HT_1A protein, whereas EOs of J. sambac and M. denudata exerted significantly different effects when compared with the model group, as determined by western blotting.

This study investigates the modulatory effects of nicergoline, a major bioactive compound derived from ergot fungus, on the 5-hydroxytryptamine 3A (5-HT3A) receptor. Utilizing a two-electrode voltage-clamp technique, we evaluated the impact of nicergoline on the 5-HT-induced inward current (I_5-HT) in 5-HT3A receptors. Our findings reveal that nicergoline inhibits I_5-HT in a reversible and concentration-dependent manner. Additionally, the observed voltage-dependent and use-dependent inhibition indicates that nicergoline acts as an open channel blocker of the 5-HT3A receptor. To further elucidate the interaction between nicergoline and the 5-HT3A receptor, we conducted molecular docking studies. Overactivation of the 5-HT3A receptor can enhance excitatory neurotransmission, potentially leading to heightened anxiety and stress responses. It may also interfere with hippocampal functions, adversely affecting learning and memory. Additionally, exceed activation of these receptors is a primary mechanism underlying nausea and vomiting, commonly observed during chemotherapy or in response to certain toxins. Collectively, our results suggest that nicergoline has the potential to inhibit 5-HT3A receptor activity by interacting with binding residues L260 and V264. This inhibition may enhance cognitive function by stabilizing neural circuits involved in cognitive processes and can improve cognitive symptoms in patients with dementia. Additionally, the anxiolytic effects resulting from 5-HT3A receptor inhibition could promote overall psychological well-being in affected individuals. Thus, the role of nicergoline as a 5-HT3A receptor antagonist not only highlights its therapeutic potential but also warrants further exploration into its mechanisms and broader implications for managing neurodegenerative diseases.

Vibrio vulnificus, an opportunistic human pathogen, employs biofilm formation as a key survival and virulence mechanism. BrpT, a transcriptional regulator, is essential for V. vulnificus biofilm development by regulating the expression of biofilm-related genes. In this study, we aimed to identify a small molecule inhibitor of BrpT to combat V. vulnificus biofilm formation. High-throughput screening of 7,251 compounds using an Escherichia coli reporter strain carrying the arabinose-inducible brpT gene and a BrpT-activated promoter fused to the luxCDABE operon identified a hit compound, BTI (BrpT Inhibitor). BTI potently inhibited BrpT activity in V. vulnificus (EC₅₀ of 6.48 μM) without affecting bacterial growth or host cell viability. Treatment with BTI significantly reduced the expression of the BrpT regulon and impaired biofilm formation and colony rugosity in V. vulnificus, thus increasing its susceptibility to antibiotics. In vitro biochemical analyses revealed that BTI directly binds to BrpT and inhibits its transcriptional regulatory activity. The identification of BTI as a specific inhibitor of BrpT that effectively diminishes V. vulnificus biofilm formation provides a promising foundation for the development of novel anti-biofilm strategies, with the potential to address the growing challenge of antibiotic resistance and improve the treatment of biofilm-associated infections.

In this study, multifunctional soil bacteria, which can promote plant development, resist heavy metals, exhibit anti-phytopathogenic action against plant diseaes, and produce extracellular enzymes, were isolated to improve the effectiveness of phytoremediation techniques. In order to isolate multifunctional soil bacteria, a variety of soil samples with diverse characteristics were used as sources for isolation. To look into the diversity and structural traits of the bacterial communities, we conducted amplicon sequencing of the 16S rRNA gene on five types of soils and predicted functional genes using Tax4Fun2. The isolated bacteria were evaluated for their multifunctional capabilities, including heavy metal tolerance, plant growth promotion, anti-phytopathogenic activity, and extracellular enzyme activity. The genes related to plant growth promotion and anti-phytopathogenic activity were most abundant in forest and paddy soils. Burkholderia sp. FZ3 and FZ5 demonstrated excellent heavy metal resistance (≤ 1 mM Cd and ≤ 10 mM Zn), Pantoea sp. FC24 exhibited the highest protease activity (24.90 μmol tyrosine·g-DCW^-1·h^-1), and Enterobacter sp. PC20 showed superior plant growth promotion, especially in siderophore production. The multifunctional bacteria isolated using traditional methods included three strains (FC24, FZ3, and FZ5) from the forest and one strain (PC20) from paddy field soil. These results indicate that, for the isolation of beneficial soil microorganisms, utilizing target gene information obtained from isolation sources and subsequently exploring target microorganisms is a valuable strategy.

Jasminum subtriplinerve Blume tea is a traditional Vietnamese medicine used to treat impetigo, menstruation issues, and painful menstrual hematometra. Previous studies have shown that extracts and isolated compounds from J. subtriplinerve possess diverse pharmacological properties, such as antioxidant, antibacterial, and antidiabetic effects. However, their potential anticancer effects and underlying mechanisms of action have not been clear. Here, we examined the effects of J. subtriplinerve extracts against three human cancer cell lines. We also conducted in vivo analyses using a mouse model of 7,12-dimethylbenz[a]anthracene-induced breast cancer, including an investigation of changes in histological sections. The effect of the J. subtriplinerve ethyl acetate fraction on cytokine levels (IL-2, PGE2, TNF-α) in serum was determined using ELISA kits. Results showed that the ethyl acetate (EtOAc) fraction had the highest anti-proliferative activity (IC50 = 13.7 mg/ml) against the breast cancer (MCF-7) cell line, while the butanol (BuOH) and water fractions did not show any anticancer effects. Additionally, the EtOAc fraction at a dose of 14.4 mg/kg was able to elevate IL-2 levels and suppress the expression of PGE2 in the serum of mice. A remarkable decrease in the percentage of death and tumor incidence in mice was achieved following treatment with the EtOAc fraction at a dose of 14.4mg/kg. No abnormal parameters in blood were observed in the J. subtriplinerve treatment groups. These results suggest that J. subtriplinerve, when used as tea or a functional food, is nontoxic and has clear chemopreventive effects against breast cancer.

Lithospermum erythrorhizon (LE), a medicinal plant from the Boraginaceae family, is traditionally used in East Asia for its therapeutic effects on skin conditions, including infections, inflammation, and wounds. Recently, the role of extracellular vesicles (EVs) as mediators of intercellular communication that regulate inflammation and promote tissue regeneration has garnered increasing attention in the field of regenerative medicine. This study investigates exosome-like vesicles derived from LE callus (LELVs) and their potential in enhancing wound healing. In vitro studies using normal human dermal fibroblasts (NHDFs) demonstrated that LELVs significantly improved cell viability, proliferation, and wound closure, while also enhancing collagen type I synthesis, indicating anti-inflammatory and regenerative properties. For in vivo analysis, LELVs were applied to lipopolysaccharide (LPS)-induced wounds in mice, where wound healing progression was monitored over 14 days. LELV-treated wounds exhibited accelerated re-epithelialization, reduced inflammation, and improved tissue remodeling, with histological analysis revealing enhanced collagen deposition and reduced inflammatory cell infiltration. These results highlight the ability of LELVs to modulate the inflammatory response and promote wound healing. With their natural origin, low immunogenicity, and ease of production, LELVs represent a promising alternative to synthetic treatments for inflammation-associated skin injuries and hold significant potential for clinical applications in wound care.

Bacterial infections or their biofilms in diabetic foot ulcer (DFU) are a key cause of drug-resistant wounds and amputations. Cold atmospheric plasma (CAP) is well documented for its antibacterial effect and promoting wound healing. In the current study, we built an argon-based, custom CAP device and investigated its potential in eliminating laboratory and clinical bacterial strains derived from DFU. The CAP device performed as expected with generation of hydroxyl, reactive nitrogen species, and argon species as determined by optical emission spectroscopy. A dose-dependent increase in oxidation reduction potential (ORP) and nitrites in the liquid phase was observed. The CAP treatment eliminated both gram-positive (Staphylococcus aureus, Entrococcus faecalis) and negative bacteria (Pseudomonas aeruginosa, Proteus mirabilis) laboratory strains. Clinical samples collected from DFU patients exhibited a significant decrease in both types of bacteria, with gram-positive strains showing higher susceptibility to the CAP treatment in an ex vivo setting. Moreover, exposure to CAP of polymicrobial biofilms from DFU led to a notable disruption in biofilm and an increase in free bacterial DNA. The duration of CAP exposure used in the current study did not induce DNA damage in peripheral blood lymphocytes. These results suggest that CAP could serve as an excellent tool in treating patients with DFUs.