Folia microbiologica最新文献

In recent decades, there has been a growing interest in harnessing plant growth-promoting rhizobacteria (PGPR) as a possible mechanism to mitigate the environmental impact of conventional agricultural practices and promote sustainable agricultural production. This study investigated the transferability of promising PGPR research from maize to another Poaceae cereal crop, wheat. This multi-seasonal study evaluated the wheat grain yield effect of Lysinibacillus sphaericus (T19), Paenibacillus alvei (T29) when applied i. individually, ii. as a consortium with Bacillus safensis (S7), and iii. at a 75% reduced fertilizer rate. Whole genome sequencing allowed annotation of genes linked to plant growth promotion, providing potential genomic explanations for the observed in-field findings. Application of the consortium compared to a commercial PGPR showed significantly increased wheat yield by 30.71%, and 25.03%, respectively, in season one, and 63.92% and 58.45%, respectively, under reduced fertilizer rates in season two. Individual application of T19 and T29 showed varying results, with T19 increasing wheat yield by 9.33% and 16.22% during seasons three and four but a substantial reduction (33.39%) during season five. T29 exhibited yield increases during season three (9.31%) and five (5.61%) but led to a significant reduction (21.15%) in season four. Genomic analysis unveiled a spectrum of plant growth-promoting genes including those associated with ammonification, phosphate solubilization, ethylene, siderophore, catalase, and superoxide dismutase production. These findings offer valuable insights into the mechanisms behind observed field results, with potential implications for advancing sustainable agriculture and crop productivity in evolving agricultural landscapes.

A recently discovered source for infection of slaughter pigs, and thus entry for bacteria into the food chain, is the installed drinking equipment in lairage pens of pig abattoirs. To mitigate this, nano-coating of stainless steel, currently used in human medicine fields as well as in other parts of the food chain, appears as promising technology. In this study, silicon dioxide nano-coating was applied to six drinkers and installed for one and three months in a lairage of a pig abattoir, while results were compared with those of drinkers that had not been nano-coated. Laboratory examination of eight sample types related to the drinkers was conducted for total aerobic plate count, Enterobacteriaceae count, Pseudomonas spp. count, Salmonella presence, pathogenic Yersinia enterocolitica presence, Listeria monocytogenes presence and methicillin-resistant Staphylococcus aureus presence. The nipple drinker, which the pigs take into their mouth for drinking, was then examined using scanning electron microscopy and elemental analysis. The nano-coating did not produce statistically significant reductions in the loads or presence of these bacteria compared to the same but uncoated drinking equipment used under the same conditions. Further studies should focus on the implementation of combined methods, such as nano-coating and sanitary treatment, as well as modifications to the coating itself, to produce meaningful reductions of the bacterial loads on/in abattoir lairage drinking equipment.

Bacterial biofilms exhibit remarkable resistance against conventional antibiotics and are capable of evading the humoral immune response. They account for nearly 80% of chronic infections in humans. Development of bacterial biofilms on medical implants results in their malfunctioning and subsequently leads to high mortality rates worldwide. Therefore, early and precise diagnosis of bacterial biofilms on implanted medical devices is essential to prevent their failure and associated complications. Culture-based methods are time consuming, more prone to contamination and often exhibit low sensitivity. Different molecular, imaging, and physical methods can aid in more accurate and faster detection of implant-associated bacterial biofilms. Biofilm growth on implant surface can be prevented either through modification of the implant material or by application of different antibacterial coatings on implant surface. Experimental studies have shown that pre-existing biofilms from medical implants can be removed by breaking down biofilm matrix, utilizing physical methods, nanomaterials and antimicrobial peptides. The current review delves into mechanism of biofilm formation on implanted medical devices and the subsequent host immune response. Much emphasis has been laid on different ongoing diagnostic and therapeutic strategies to achieve improved patient outcomes and reduced socio-economic burden.

The increasing prevalence of neurodegenerative diseases is a formidable task due to their multifactorial causation and treatments limited to disease maintenance and progression. Epstein-Barr virus (EBV) is reported to be involved with neuropathologies; previous studies from our group suggested the effective binding of epigallocatechin-3-gallate (EGCG) with EBV nuclear antigen 1 (EBNA1) and glycoprotein H (gH). Therefore, in the current study, we evaluated the anti-EBV effect of ECGG on the neuronal cells. EBV-GFP exhibited a decline after EGCG treatment. We have observed a decrease in specific latent and lytic cycle genes. EBNA1 unravelled attenuation at day 1 (D1), whereas EBNA3B, EBNA3C, BMRF1, BZLF1, and gp350 showed major downregulation in D3 compared to EBV infection. Notably, EBNA-LP has shown mitigation in both the considered time points. Inflammatory and chemokine moieties like IL-6, CCR1, CCR3, and CCR5 declined upon EGCG treatment, while IL-10 exhibited elevation. Transcription factor STAT3 and NF-kB were decreased, especially in the pre-EGCG treated samples. Subsequently, restoration in the mitochondrial membrane potential was observed after EGCG treatment. We observed an increase in the mitochondrial fission genes like DRP1 and MiD49, and not many regulations were observed in the mitochondrial fusion genes except MFN2. Furthermore, the CytC, CytC oxidase, MAVS, ANT, and SDH exhibited elevation upon EGCG treatment, while ATPsyn and ABAD showed downregulation. Dysfunction of mitochondria is further related to apoptosis of neurons. Herein, we were keen to examine the level of amyloid-precursor protein (APP), and it has also indicated declined after EGCG treatment. Altogether, the current study demonstrated the anti-EBV effect of EGCG by subsiding the EBV-mediated inflammation and amendments in the neuropathological markers.

Ginsenoside Rh2(S) is well-known for its therapeutic potential against diverse conditions, including some cancers, inflammation, and diabetes. The enzymatic activity of uridine diphosphate glycosyltransferase 51 (UGT51) from Saccharomyces cerevisiae plays a pivotal role in the glycosylation process between UDP-glucose (donor) and protopanaxadiol (acceptor), to form ginsenoside Rh2. However, the catalytic efficiency of the UGT51 has remained a challenging task. To this end, we employed site-directed mutagenesis on UGT51 to improve its catalytic efficiency for enhanced production of ginsenoside Rh2. The mutated structure, featuring four key mutations (E805A, S998A, R1031A, and L1032A), exhibited heightened stability, binding affinity, and active site accessibility for protopanaxadiol (PPD) compared to the wild type. Under in vitro conditions, three mutants (E805A, R1031A, and L1032A) demonstrated 10%, 58%, and 65% higher enzymatic activities compared to the wild strain. Notably, the double mutant R1031A/L1032A exhibited an 85% increase in activity. Employing a fed-batch technology with PPD as the substrate yielded a Rh2 production of 4.663 g/L. The molecular dynamics (MD) simulations were employed to investigate the movements and dynamic dynamics of UGT51 mutations and PPD complexes. The root mean square deviation (RMSD) analysis revealed substantial alterations in structural conformation, particularly in the R1031A/L1032A mutations, correlating with boosted catalytic efficiency. Furthermore, the root mean square fluctuation (RMSF) simulation study aligned with both the RMSD and the solvent-accessible surface area (SASA) analyses. The computationally guided site-directed mutagenesis approach holds promise for extending its application to the development of commercially significant enzymes.

Medical students are exposed to the hospital environment and patients during their studies, increasing the risk of exposure to virulent and antibiotic-resistant isolates of Staphylococcus aureus. The aim of the study is to determine the prevalence of Staphylococcus aureus among medical students who have varying levels of exposure to the hospital environment to provide valuable insights into the risk of colonization and transmission. Nasal swabs and fingerprints were obtained and cultured on a selective medium for staphylococci. The obtained isolates were confirmed as methicillin-sensitive S. aureus (MSSA) or methicillin-resistant (MRSA) using PCR. Antibiotic resistance, the presence of virulence genes including enterotoxin encoding genes, and spa typing were performed. Among pre-clinical students, MSSA was detected on the nose in 45.2% and on the fingerprints in 10.6% of the participants. Among clinical students, MSSA was detected on the nose in 42.0% and on the fingerprints in 25.4%. Only one MRSA isolate was obtained. Genes seg and sei were the most frequently detected in both student groups, with their presence in over 40% of isolates among clinical students. The eta and etb genes were mainly detected from the nose in both student groups. In pre-clinical students, S. aureus carrying eta gene occurred in 6.4% and etb in 8.5%. In clinical students, the occurrence was 5.1% for eta and 8.5% for etb. The tst gene was identified only in the nose and fingerprints of the clinical student group. The most frequently observed resistance was to clindamycin and erythromycin. In total 58 different spa types were identified. High rates of asymptomatic MSSA carriage were observed in both groups of medical students. Detected MSSA strains showed a high degree of genetic variability, with a number of them carrying the virulence and antibiotic resistance genes. Although students do not exhibit increased risk to their patient's, increased hygiene is required in asymptomatic carriage personnel. The overall prevalence of MRSA was low, with a minimal risk of spread.

The role of aeromonads as contributors to gastrointestinal pathology remains controversial. The aim of this study was to analyse the clinical characteristics and risk factors for the acquisition of an enteric infection by Aeromonas spp. in patients with digestive or nephrological diseases. The method user for the study comprised a retrospective review of the clinical history of all patients in whom Aeromonas spp. was isolated in faeces. The study period included in samples arriving at the microbiology service of the Marqués de Valdecilla University Hospital, from 2016 to 2022. The results showed that there was an increase in the more virulent Aeromonas species in the patients studied. The most common chronic diseases were cancer, inflammatory bowel disease and alcoholic cirrhosis, as well as biliary involvement in acute cases. In conclusión, Aeromonas is a genus to consider in patients with diarrhoea and hepatonephrological involvement.

This study investigated the application of mixed biofilms formed by two Pseudomonas strains (NAA22 and NAA23) for bio-decolorization of malachite green (MG) dye. The isolated strains displayed biofilm formation and MG decolorization capabilities. Mixed biofilms exhibited significantly greater biofilm formation and MG decolorization (94.3%) compared to individual strains, suggesting synergistic interactions. This decolorization efficiency surpassed previously reported values for single strain decolorization. The mixed biofilms tolerated a broad range of temperatures (20-40 °C) and pH (5-9), with optimal decolorization at neutral or slightly acidic conditions (pH7.0). Enzyme analysis revealed laccase, NADH-DCIP reductase, and azoreductase as key contributors to MG decolorization, with significantly higher activity in mixed biofilms. Importantly, the bio-decolorization process transformed MG into non-phytotoxic compounds, demonstrated by seed germination and growth assays. These findings propose a promising and environmentally safe approach for MG bioremediation using mixed Pseudomonas biofilms.

The contamination of food and animal feeds with mycotoxions, particularly aflatoxin B1 (AFB1), poses significant risks to human health and causes economic losses. This study investigated bacteria from various fermented milk products to assess their ability to detoxify AFB1. A variety of household fermented kefir milk, kefir-like beverages, and kefir grains were collected from rural areas and subjected to microbiological analysis. Gram-positive bacterial isolates were further identified based on the 16S rRNA gene homology analysis. Seven bacterial isolates that were initially identified as lactic acid bacteria were selected for their potential to detoxify AFB1. Effects of environmental factors, including temperature, time, pH, and cell concentration, as well as bacterial components such as inoculum, fermentation supernatant, and cells, were evaluated on AFB1 detoxification. The most frequent isolates belonged to the new genus Lentilactobacillus and Lactiplantibacillus, of which three strains were identified as L. kefiri, L. diolivorans, and L. plantarum. The selected L. plantarum isolate demonstrated optimal AFB1 detoxification at pH 4, a 4-h exposure time, and a cell concentration of 1.0 × 10¹⁶ CFU/mL. Significant differences were observed in toxin removal between fermentation supernatant and cells, while temperature showed no significant effect on toxin detoxification. This study demonstrated the high ability of L. plantarum for AFB1 detoxification, suggesting potential applications for food and feed safety enhancement. Further research is warranted to optimize its effectiveness and explore broader applications.

Cells of the methylotrophic yeast Ogataea parapolymorpha have two genes encoding low-affinity phosphate transporters: PHO87, encoding the plasma membrane transporter, and PHO91, encoding a protein, which is homologous to the Saccharomyces cerevisiae vacuolar membrane transporter. Earlier, we reported that inactivation of PHO91 in O. parapolymorpha interferes with methanol utilization due to the lack of activity of methanol oxidase encoded by the MOX gene. In this work, we showed that this defect was completely suppressed by inactivating the PHO87 gene or introducing additional copies of the MOX gene into the cell. The PHO91 gene knockout decreased the level of long-chained polyphosphates only in methanol-grown cells, but not in glucose-grown cells. This effect remained even in the strain with extra copies of MOX, which rescues the ability of the mutant to grow on methanol. In contrast, the PHO87 gene knockout changed the levels of short-chained and long-chained polyphosphates in both methanol- and glucose-grown cells. Inactivation of PHO91 did not change vanadate resistance, while inactivation of PHO87 increased this resistance. Our data suggest that in O. parapolymorpha, Pho87 and Pho91 transporters have different roles in inorganic polyphosphate metabolism and adaptation to methanol consumption.