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Bariatric surgery is vital for sustainable weight loss and metabolic improvement in obese individuals, but its effects on gut microbiota and their role in these benefits require further investigation. Investigate the temporal changes in gut microbiota in obese patients undergoing bariatric surgery (gastric sleeve gastrectomy or Roux-en-Y Gastric Bypass (RYGB)) compared to healthy controls, aiming to understand their role in weight loss and metabolic health improvement. A case-control study included 30 obese patients aged 65-95 undergoing bariatric surgery, and 18 matched healthy controls. Selection criteria were based on age, race, BMI, history of antibiotics, probiotics, and prebiotics usage. Stool samples were collected at baseline, three months, and six months post-surgery for DNA extraction and quantitative real-time PCR analysis to assess gut microbiota changes. Physical activity and dietary intake were evaluated using standardized questionnaires. Statistical analyses were performed using R. Post-surgery, patients showed significant reductions in weight and BMI, with changes in dietary habits and physical activity. Quantitative real-time PCR analysis revealed substantial alterations in bacterial groups such as Bacteroides and Fusobacterium. However, some groups showed no significant changes, indicating a complex interaction between gut microbiota and bariatric surgery. Notable correlations were found between body weight, BMI, and specific bacterial groups like the C. cluster IV and Lactobacillus, particularly in RYGB patients. Bariatric surgery significantly alters gut microbiota, aiding weight loss and metabolic regulation in obese patients. Understanding these changes is crucial for developing effective obesity management strategies, requiring further research to optimize outcomes.

Postbiotics are the non-viable bacterial products or the low molecular weight metabolites produced by probiotics that have received considerable attention owing to their health promoting effects. The present study aimed to investigate the safety and antibacterial properties of postbiotic components of Lacticaseibacillus rhamnosus (Lra) and Limosilactobacillus reuteri (Lre) for their potential applications in food products. The freeze dried postbiotic metabolites (FD-P) from Lra and Lre were extensively analyzed for their physico-chemical properties and antibacterial actions against common food borne pathogens. Higher levels of total flavonoids (1971.79 ± 20 mg Qu/ g), total short-chain fatty acid (23 µg/g), sugar contents, CAT, and SOD anti-oxidative enzymes were detected in the Lra postbiotic, while GSH-px levels and riboflavin were higher in Lre postbiotics (P < 0.01). No significant differences were recorded in the total phenolic (2501 and 2518 mg GAE/ L) and crude protein contents (305. 58 and 296.23 µg/g) of the postbiotics (p ≥ 0.05), respectively. Both FD-P samples showed enhanced activities against Gram-Positive pathogens compared to Gram-Negative pathogens (p < 0.05), while combining the two postbiotics further potentiated the antibacterial actions. Both FD-P samples were non-hemolytic to human erythrocyte cells, and exhibited low cytotoxicity in MRC 5 and IPEC-J2 cell lines at the highest used concentrations (150 mg/ml). In summary, the postbiotics derived from Lra and Lre are safe bioactive ingredients with enhanced antibacterial and antioxidant capabilities, having potential applications as a natural preservatives in food system, potentially enhancing safety and extending the shelf life of food products.

The functionality of Moloney murine leukemia virus reverse transcriptase (MMLV RT) will increase with the improvement of its solubility and thermal stability. Introduce directed mutation at specific positions of the MMLV RT sequence and codon optimization is needed to achieve these properties. The two RT coding sequences with (rRT-K) and without directed mutations (rRT-L) were versatility optimized and expressed to analyze the ribonuclease H (RNase H) inactivity and thermostable polymerase activity. For this purpose, the five-point mutations (438-442aa) and three-point mutations (530, 568, and 659 aa) were done at the RT connection domain and RNase H active site, respectively. High expression levels of rRT-L and rRT-K were obtained in E. coli BL21(DE3) and BL21(shuffle) strains, 0.5 mM IPTG concentration at 37 °C, and 8 hours' post-induction condition. Then, recombinant enzymes were purified and verified by Ni-NTA resin and western blotting. Insilico analysis (IUpred 3.0) showed that the directed mutation in the RNase H domain caused the formation of disorder regions or instability in the RNase H domain of rRT-K compared to rRT-L. The modified RT-PCR and the RT-LAMP reactions proved the RNase H inactivity of rRT-K. In addition, increasing of thermostability of rRT-K compared to rRT-L and commercial RT was evaluated by the RT-PCR and RT-LAMP reactions. The results showed that rRT-K could successfully tolerate 60 ºC in the two methods. This study revealed that the directed mutations and the versatile sequence optimization can promise to produce thermostable commercial enzymes to decrease non-specific one-step RT-PCR and RT-LAMP products.

The continuous growth of biofilm infections and their resilience to conventional cleaning methods and antimicrobial agents pose a worldwide challenge across diverse sectors. This persistent medical, industrial, and environmental issue contributes to treatment challenges and chronic diseases. Lactic acid bacteria have garnered global attention for their substantial antimicrobial effects against pathogens and established beneficial roles. Notably, their biofilms are also predicted to show a promising control strategy against pathogenic biofilm formation. The prevalence of biofilm-related problems underscores the need for extensive research and innovative solutions to tackle this global challenge. This novel study investigates the effect of different extracts (external, internal, and mixed extracts) obtained from Lactobacillus rhamnosus GG biofilm on pathogenic-formed biofilms. Subsequently, external extracts presented an important eradication effectiveness. Furthermore, a 6-fold concentration of these extracts led to eradication percentages of 57%, 67%, and 76% for Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa biofilms, respectively, and around 99.9% bactericidal effect of biofilm cells was observed for the three strains. The results of this research could mark a significant breakthrough in the field of anti-biofilm and antimicrobial strategies. Further studies and molecular research will be necessary to detect the molecules secreted by the biofilm, and their mechanisms of action engaged in new anti-biofilm strategies.

The research aimed to evaluate the antioxidative and antibacterial characteristics of aqueous sumac extract on methicillin-resistant Staphylococcus aureus through in-vitro and in-vivo study. Sumac extract has been obtained through the soaking method, and its antioxidant properties were gauged using the DPPH free radical scavenging method. The minimum inhibitory concentration (MIC) of sumac extract was determined on S. aureus obtained from hospitalized patients, as well as an assessment of biofilm-formation and the release of bacterial intracellular compounds. in vivo experimentation involved injecting bacteria (10⁸ cfu/ml) into mice, which subsequently manifested indicators of symptoms of infection, and the number of bacteria within their bloodstream was quantified. The Sumac extract demonstrated strong antioxidant properties at concentrations of 1000 mg/ml. Furthermore, the agar tests for the gram staining, mannitol, coagulase, and DNase revealed that 190 cultured bacteria samples were identified as Staphylococcus aureus. These bacteria were resistant to clindamycin, ciprofloxacin, and methicillin antibiotics, but sensitive to erythromycin and penicillin antibiotics. Additionally, the bacteria displayed significant methicillin resistance and formed a strong biofilm (65.78%). The sumac extract showed a MIC range of 125-1000 µg/ml against Staphylococcus aureus. Treatment with concentrations above the MIC was found to prevent the formation of biofilm and increase the release of bacterial intracellular compounds. Sumac extract led to a decrease in bacterial count in the blood of mice and reduced signs of infection. Sumac extract demonstrated powerful antioxidant and antibacterial effects against resistant microorganisms, suggesting its potential as a promising compound for the treatment of resistant infections in future research.

PA1895-1897 is a quorum sensing (QS) operon regulated by the anti-activator LuxR homologue QscR in Pseudomonas aeruginosa. We aimed to investigate its impact on bacterial metabolism, and whether it contributes to the delayed QS activation. We performed liquid chromatograph-mass spectrometer-based metabolomics using wildtype PAO1, PA1895-1897-knockout mutant, and mutant with pJN105.PA1895-1897 overexpression vector. The impact of metabolites on QS signaling molecule (3OC12-HSL and C4-HSL) concentrations, pyocyanin production, and QS gene (lasR, lasI, rhlR, and rhlI) expression was examined. Metabolomics analysis found that fatty acid biosynthesis had the highest fold enrichment among all metabolic pathways in PA1895-1897-overexpressed mutants. Among these enriched fatty acids, palmitoleic acid and acetic acid were the predominantly abundant ones that significantly affected by PA1895-1897 operon. When different doses of exogenous palmitoleic acid or acetic acid were added to the cultures of PA1895-1897 knockout mutants, their levels of 3OC12-HSL, C4-HSL, and pyocyanin were decreased in a dose-dependent manner. High doses of palmitoleic acid and acetic acid suppressed the mRNA expression of lasR, rhlR, and rhlI. Inhibition of fatty acid biosynthesis increased the production of 3OC12-HSL, C4-HSL, and pyocyanin in PA1895-1897-overexpressed cultures. Our data suggest that fatty acid synthesis is promoted by PA1895-1897 operon, and contributes the delayed expression of QS phenotypes, furthering the understanding about the regulation of bacterial QS activation.

This study aimed to evaluate the effect of nano-encapsulation of four essential amino acids (AA), threonine, methionine, tryptophan, and lysine on in vitro ruminal total gas, methane, carbon monoxide, and hydrogen sulfide production as well as the rumen fermentation profile in cattle. The highest (P < 0.001) rate and asymptotic gas production after 48 h of incubation was observed in the diets that had threonine, followed by lysine, methionine, and tryptophan. Asymptotic methane gas production decreased in the following order: threonine > lysine > tryptophan > methionine (P < 0.0001) and the rate of production per hour followed the same trend (P = 0.0259). CH₄ parameters showed that in 4 h, 24 h, and 48 h of incubation the lowest methane production was obtained in the diet with methionine (P < 0.05) and the highest one in diet supplemented with threonine. Methane fractions showed that methionine-containing diets resulted in more (P < 0.05) metabolizable energy versus methane, followed by tryptophan-containing, and then lysine-containing diets. Methionine-fortified diets seem to be the most eco-friendly among those studied regarding methane output. However, based on methane, CO, and H₂S output as well as the rumen fermentation profile nano-encapsulated lysine is recommended for use in ruminant nutrition.

Immunotoxins are widely applied for cancer therapy. However, bacterial expression of immunotoxins usually leads to the formation of insoluble and non-functional recombinant proteins. This study was aimed to improve soluble expression of a novel anti-HER2 immunotoxin under the regulation of the trc promoter in Escherichia coli by optimization of the cultivation conditions using response surface methodology (RSM). To conduct RSM, four cultivation variables (i.e., inducer concentration, post-induction time, post-induction temperature, and medium recipe), were selected for statistical characterization and optimization using the Box-Behnken design and Design Expert software. Based on the developed model using the Box-Behnken design, the optimal cultivation conditions for soluble expression of anti-HER2 immunotoxin were determined to be 0.1 mM IPTG for induction in the LB medium at 33 °C for 18 h. The expressed immunotoxin was successfully purified using affinity chromatography with more than 90% purity and its bioactivity was confirmed using cell-based ELISA. Technical approach developed in this study can be generally applied to enhance the production yield and quality of recombinant proteins using E. coli as the gene expression system.

A bacterial consortium was isolated from a soil in Noblejas (Toledo, Spain) with a long history of mixed hydrocarbons pollution, by enrichment cultivation. Serial cultures of hydrocarbons polluted soil samples were grown in a minimal medium using diesel (1 mL/L) as the sole carbon and energy source. The bacterial composition of the Noblejas Consortium (NC) was determined by sequencing 16S rRNA gene amplicon libraries. The consortium contained around 50 amplicon sequence variants (ASVs) and the major populations belonged to the genera Pseudomonas, Enterobacter, Delftia, Stenotrophomonas, Achromobacter, Acinetobacter, Novosphingobium, Allorhizobium-Neorhizobium-Rhizobium, Ochrobactrum and Luteibacter. All other genera were below 1%. Metagenomic analysis of NC has shown a high abundance of genes encoding enzymes implicated in aliphatic and (poly) aromatic hydrocarbons degradation, and almost all pathways for hydrocarbon degradation are represented. Metagenomic analysis has also allowed the construction of metagenome assembled genomes (MAGs) for the major players of NC. Metatranscriptomic analysis has shown that several of the ASVs are implicated in hydrocarbon degradation, being Pseudomonas, Acinetobacter and Delftia the most active populations.