Journal of microbiology and biotechnology最新文献

Soluble epoxide hydrolase (sEH) and pro-inflammatory cytokines are associated with the development of inhibitors for cardiovascular and inflammatory diseases. Here, we report on four natural sEH inhibitors isolated from the aerial parts of Elsholtzia ciliata (Thunb.) Hyl.. The four compounds, 1-4, were identified as luteolin-7-O-glucoside (1), yuanhuanin (2), apigenin-7-O-glucoside (3), and butein-4'-O-glucoside (4). Among them, compounds 2 and 4 are reported for the first time from this plant. In vitro and in silico, they showed inhibitory activity towards sEH at micromole concentrations. Moreover, they suppressed pro-inflammatory cytokines in polyinosinic:polycytidylic acid (poly(I:C))-stimulated RAW264.7 cells. Notably, 4 significantly downregulated the sEH catalytic reaction, NO and PGE2 production, and the expression levels of iNOS, COX-2, IL-6 mRNA, and sEH mRNA. Therefore, butein-4'-O-glucoside (4) is a potential sEH inhibitor that may be suitable for treating inflammation and cardiovascular diseases caused by infection.

Microalgae are recognized as a sustainable resource to produce biofertilizers, biofuels, and pigments, with the added benefits of environmental sustainability, such as carbon sequestration and pollutant removal. However, traditional cultivation methods face challenges like low biomass productivity and high operational costs. This review focuses on the innovative use of hydrogels as a medium for microalgae cultivation, which addresses these challenges by enhancing nutrient permeability, light distribution, and overall growth efficiency. Hydrogels provide a three-dimensional matrix that not only supports higher biomass yields but also facilitates the removal of pollutants from wastewater, contributing to circular economy goals. The review also explores the environmental benefits, challenges, and prospects of integrating hydrogel technology into microalgae cultivation systems. By highlighting influencing factors through which hydrogels improve microalgal productivity and environmental outcomes, this work aims to provide insights into the potential of hydrogel-based systems for sustainable development.

Alcoholic liver disease (ALD) poses a significant global health burden, often requiring liver transplantation and resulting in fatalities. Current treatments, like corticosteroids, effectively reduce inflammation but carry significant immunosuppressive risks. This study evaluates Lactiplantibacillus plantarum FB091, a newly isolated probiotic strain, as a safer alternative for ALD treatment. Using an in vivo mouse model, we assessed the effects of L. plantarum FB091 on alcohol-induced liver damage and gut microbiota composition. Alcohol and probiotics administration did not significantly impact water/feed intake or body weight. Histopathological analysis showed that L. plantarum FB091 reduced hepatocellular ballooning and inflammatory cell infiltration in liver tissues and mitigated structural damage in colon tissues, demonstrating protective effects against alcohol-induced damage. Biomarker analysis indicated that L. plantarum FB091 decreased aspartate aminotransferase levels, suggesting reduced liver damage, and increased alcohol dehydrogenase activity, indicating enhanced alcohol metabolism. Additionally, cytokine assays revealed a reduction in pro-inflammatory TNF-α and an increase in anti-inflammatory IL-10 levels in colon tissues of the L. plantarum FB091 group, suggesting an anti-inflammatory effect. Gut microbiota analysis showed changes in the L. plantarum FB091 group, including a reduction in Cyanobacteria and an increase in beneficial bacteria such as Akkermansia and Lactobacillus. These changes correlated with the recovery and protection of liver and colon health. Overall, L. plantarum FB091 shows potential as a therapeutic probiotic for managing ALD through its protective effects on liver and colon tissues, enhancement of alcohol metabolism, and beneficial modulation of gut microbiota. Further clinical studies are warranted to confirm these findings in humans.

This study was planned to determine the colistin-resistant (CR) gene distribution among two species of gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae. In total, 50 isolates of K. pneumoniae (14 isolates, 28%) and P. aeruginosa (36 isolates, 72%) were isolated between August 2023 and October 2023 from clinical wound samples at Jinnah Hospital and Lahore General Hospital Lahore, Pakistan. To determine the resistance genes linked to CR and assess antimicrobial susceptibility, all isolates were kept at -80°C in 15% glycerol broth. Using the right primer sets, a polymerase chain reaction (PCR) was utilized to identify the CR-associated mcr-1 gene of the gram-negative isolates. Out of 50, 40 isolates (80%) showed resistance against colistin with MICs of 8 and 128 μg/ml. The majority (97%) of P. aeruginosa CR strains were considered multidrug resistant (MDR). All K. pneumoniae isolates were resistant to cefepime, cotrimoxazole, ceftriaxone, and imipenem. The clinical CR isolates of P. aeruginosa were highly resistant to ceftriaxone, imipenem, cefepime, cotrimoxazole, ciprofloxacin, amikacin, and piperacillin/tazobactum. The antibiotic resistance pattern was terrifyingly high among both bacterial species. According to the PCR results, CR was prevalent among the gram-negative samples, and the mcr-1 gene was positive in 6/40 (15%) of the CR isolates, including four P. aeruginosa and two K. pneumoniae strains. The high CR (80%) reported in this research is cause for concern and underscores an urgent need to use colistin in a limited and logical manner, similar to other antibiotics.

The gut microbiome is an important and the largest endocrine organ linked to the microbes of the GI tract. The bacterial, viral and fungal communities are key regulators of the health and disease status in a host at hormonal, neurological, immunological, and metabolic levels. The useful microbes can compete with microbes exhibiting pathogenic behavior by maintaining resistance against their colonization, thereby maintaining eubiosis. As diagnostic tools, metagenomic, proteomic and genomic approaches can determine various microbial markers in clinic for early diagnosis of colorectal cancer (CRC). Probiotics are live non-pathogenic microorganisms such as lactic acid bacteria, Bifidobacteria, Firmicutes and Saccharomyces that can help maintain eubiosis when administered in appropriate amounts. In addition, the type of dietary intake contributes substantially to the composition of gut microbiome. The use of probiotics has been found to exert antitumor effects at preclinical levels and promote the antitumor effects of immunotherapeutic drugs at clinical levels. Also, modifying the composition of gut microbiota by Fecal Microbiota Transplantation (FMT), and using live lactic acid producing bacteria such as Lactobacillus, Bifidobacteria and their metabolites (termed postbiotics) can contribute to immunomodulation of the tumor microenvironment. This can lead to tumor-preventive effects at early stages and antitumor effects after diagnosis of CRC. To conclude, probiotics are presumably found to be safe to use in humans and are to be studied further to promote their appliance at clinical levels for management of CRC.

Since microalgae face various environmental stresses for the high production of biofuels, multiple studies have been performed to determine if microalgae are resistant to these various stresses. In this study, the viability of cells under various abiotic stresses was investigated by introducing a putative germin-like protein (GLP) from Neopyropia yezoensis, which was known to be related in the resistance to abiotic stresses. The expression of GLP in Chlamydomonas reinhardtii allowed cells to grow better in various abiotic stress environments. In nitrogen starvation conditions, recombinant cells accumulated the lipid droplet 1.46-fold more than wild-type cells and responded more rapidly to form palmelloid forms. Under high-temperature, hydrogen peroxide conditions and saline stress, the survival rate was increased 3.5 times, 2.19 times, and 3.19 times in recombinant C. reinhardtii with GLP, respectively. The expression level of genes related to pathways in response to various stresses increased 2-fold more under those conditions. This result will be useful for the development of microalgae that can grow better and produce more biofuels under different stress conditions.

In this study, a novel species within the genus Paracoccus was isolated from the coastal soil of Dokdo (Seodo) Island and investigated. We elucidated the novel species, designated MBLB3053^T, through genomic analysis of novel functional microbial resources. Cells were gram-negative, non-motile, and coccoid, and the colony was light orange in color. Phylogenetic analysis based on the 16S rRNA gene showed that strain MBLB3053^T was related to the genus Paracoccus, with 98.5% similarity to Paracoccus aestuariivivens. Comparative genome analysis also revealed the strain to be a novel species of the genus Paracoccus by average nucleotide identity and in silico DNA-DNA hybridization values. Through secondary metabolite analysis, terpene biosynthetic gene clusters associated with carotenoid biosynthesis were found in strain MBLB3053^T. Using high-performance liquid chromatography, strain MBLB3053^T was confirmed to produce carotenoids, including all-trans-astaxanthin, by comparison to the standard compound. Notably, the isolate was also confirmed to produce carotenoids that other closely related species did not produce. Based on this comprehensive polyphasic taxonomy, strain MBLB3053^T represents a novel species within the genus Paracoccus, for which the name Paracoccus aurantius sp. nov is proposed. The type strain was MBL3053^T (=KCTC 8269^T =JCM 36634^T). These findings support the research and resource value of this novel species, which was isolated from the Dokdo environmental microbiome.

The aquaculture industry faces significant challenges due to bacterial infections caused by Edwardsiella tarda, Photobacterium damselae, and Vibrio harveyi. The extensive use of traditional antibiotics, has resulted in widespread antibiotic resistance. This study aimed to investigate the antibacterial potential of the brown seaweed Eisenia bicyclis, particularly its synergistic effects with antibiotics against these fish pathogenic bacteria. E. bicyclis were processed to obtain methanolic extracts and fractionated using different polar solvents. The antibacterial activities of these extracts and fractions were assessed through disc diffusion and minimum inhibitory concentration (MIC) assays. The study further evaluated the antibiotic susceptibility of the bacterial strains and the synergistic effects of the extracts combined with erythromycin and oxyteteracycline using the fractional inhibitory concentration index. Results showed that the ethyl acetate (EtOAc) fraction of E. bicyclis methanolic extract exhibited the highest antibacterial activity. The combination of the EtOAc fraction with erythromycin significantly enhanced its antibacterial efficacy against the tested strains. This synergistic effect was indicated by a notable reduction in MIC values, demonstrating the potential of E. bicyclis to enhance the effectiveness of traditional antibiotics. The findings suggest that E. bicyclis extracts, particularly the EtOAc fraction, could serve as a potent natural resource to counteract antibiotic resistance in aquaculture.

In order to provide the qualitative data for the 20 commercially available krill oil supplementary products, the levels of omega-3 polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), fatty acid compositions, and chemical indices, including acid values, of the supplements, were determined. The acid values ranged from 7.4 to 43.7 mg of potassium hydroxide (KOH)/ g of oil. The relative percentages of EPA and DHA in the oils ranged from 14.2 to 34.8 % (w/w). Although all 20 krill oil supplements used 100% krill oil as raw material, the fatty acid composition of 4 samples differed from typical krill oil in terms of the content of myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), linoleic acid (C18:2, n-6), and eicosenoic acid (C20:1, n-9). Accordingly, the Ministry of Food and Drug Safety recently standardized linoleic acid (3% or less) and myristic acid (5-13%) as part of the fatty acid components of krill oil. This study provides a reference for analyzing the chemical and nutritional properties and evaluating the adulteration of krill oil supplements in the Korean market.

The emergence and spread of multidrug-resistance (MDR) pathogenic Escherichia coli due to horizontal gene transfer of antibiotic resistance genes (ARGs) and virulence factors (VFs) is a global health concern, particularly in developing countries. While numerous studies have focused on major sequence types (STs), the implication of minor STs in ARG dissemination and their pathogenicity remains crucial. In this study, two E. coli strains (PEC1011 and PEC1012) were isolated from wild bird feces in Pakistan and identified as ST2178 based on their complete genome sequences. To understand this minor ST, 204 genome assemblies of ST2178 were comparatively analyzed with the isolates' genomes. The phylogenetic analyses revealed five subclades of ST2178. Subclade E strains were predominantly isolated from human specimens, whereas subclades A and B strains including strains PEC1011 and PEC1012, respectively, were frequently isolated from animal. Mobile genetic elements (MGEs) exhibited the positive correlation with ARGs but not with VFs in this ST. Plasmid-borne ARGs exhibited higher correlation with plasmid-borne MGEs, indicating the role of diverse mobile plasmid structures in ARG transmission. Subclade E exhibited diverse plasmid-borne ARG repertoires correlated with MGEs, marking it as a critical surveillance target. In the case of VFs, they exhibited phylogeny-dependent profiles. Strain PEC1012 harbored various plasmid-borne ARGs, which are similar with conserved ARG repertoires in subclade A. The presence of unique ARG insertion in pPEC1012 highlights the importance of subclade A in ARG dissemination. This study comprehensively elucidates the landscape of ST2178, identifying critical phylogenetic subclades and their characteristics in ARG and VF occurrence.