Probiotics and Antimicrobial Proteins最新文献

Atherosclerosis is a major cause of cardiovascular disease (CVD). The trimethylamine (TMA)-trimethylamine N-oxide (TMAO) pathway is a key crossover pathway highly associated with diet, gut microbiome, and atherosclerosis. The Bifidobacterium animalis subsp. lactis F1-3-2 (Bif. animalis F1-3-2, No. CCTCCM2020832) was screened through in vitro and in vivo experiments in the early stage of this study with excellent lipid-lowering and anti-inflammatory function. By building an atherosclerosis model and focusing on TMAO, the specific mechanism of Bif. animalis F1-3-2 to improve atherosclerosis was explored. The study found that Bif. animalis F1-3-2 effectively improved the accumulation of aortic plaque in atherosclerotic mice. The strain improved lipid metabolism in serum and liver. It decreased the serum TMA and TMAO, regulated bile acid composition, participated in the farnesoid X receptor (FXR) pathway to improve lipid metabolism, and further reduced the aortic macrophage foam cell accumulation. In addition, the strain could improve the structure of the intestinal microbiome and reduce the proportion of Firmicutes and Bacteroidetes. The abundance of Turicibacter, Clostridium sensu stricto_1, and Romboutsia was reduced at the genus level. The differential microbiota is highly correlated with bile acid metabolism, which is speculated to be involved in ameliorating atherosclerotic lipid metabolism disorders.

The escalating prevalence of antibiotic-resistant bacteria has emerged as a formidable threat to global health, and the quest for alternative antimicrobial agents is imperative. Cecropins, a class of antimicrobial peptides (AMPs), have garnered attention due to their potent bactericidal properties. This investigation delves into the antibacterial prowess of Cecropin A (CA) and Cecropin AD (CAD), showcasing their robust activity against Gram-negative bacteria, inclusive of multidrug-resistant bacteria. The bactericidal efficacy of CA and CAD is characterized by a dose-responsive paradigm, affirming their potential as therapeutic agents. These peptides exhibit minimal cytotoxicity and hemolytic effects, underscoring their safety profile. Advanced experimentation has elucidated that cecropins could disrupt the outer bacterial membrane, targeting lipid A, a pivotal constituent of the lipopolysaccharides (LPS) in the outer membrane as their antimicrobial bullseye. The affinity of cecropins for LPS and their antimicrobial action underscore the therapeutic potential of these peptides in targeting Gram-negative bacterial infections. These insights accentuate the promise of cecropins as viable "antibiotic substitutes," paving the path for their expanded application in combating antibiotic resistance.

Eubacterium rectale (E. rectale) has the ability to attenuate systemic and intestinal inflammation. Its naturally secreted membrane vesicles (MVs) likely play a crucial role in this process. The objective of this study is to investigate the anti-inflammatory effects of E. rectale and its membrane vesicles (MVs). An inflammation model was established by inducing an inflammatory response in Raw 264.7 cells using lipopolysaccharide (LPS). Subsequently, the cells were pre-treated with E. rectale and its MVs, and the expression levels of IL-1β, IL-6, TNF-α, and IL-10 in the cells were then detected using RT-qPCR. ELISA was used to measure the secretion levels of IL-1β, while western blot analysis was employed to assess the expression of key proteins in the IL-1β pathway, specifically ASC, Caspase 1, and NLRP3. The results revealed that both E. rectale and its MVs significantly reduced the expression of the inflammatory cytokines IL-1β and TNF-α in Raw 264.7 cells, which were induced by LPS. Additionally, they markedly upregulated the expression of the anti-inflammatory cytokine IL-10 and suppressed IL-1β expression via the NLRP3-Caspase 1-ASC signaling pathway. These findings suggest that E. rectale, through its membrane vesicles, can attenuate LPS-induced NLRP3 inflammasome activation, thereby mitigating the inflammatory response in Raw 264.7 cells.

The human defensins are a group of cationic antimicrobial peptides that range in size from 2 to 5 kDa and share a common structural motif of six disulphide-linked cysteines. Several naturally occurring human α- and β-defensins have been identified over the past two decades. They have a wide variety of antimicrobial effects, and their potential to avoid the development of resistance to antimicrobial treatment makes them attractive as therapeutic agents. Human defensins have recently been the focus of medical and molecular biology studies due to their promising application in medicine and the pharmaceutical industry. This work aims to provide a comprehensive summary of the current developments of human defensins, including their identification, categorization, molecular features, expression, modes of action, and potential application in medical settings. Current obstacles and future opportunities for using human defensins are also covered. Furthermore, we shed light on the potential of this class as an antiviral agent, particularly against SARS CoV-2, by providing an in silico-based investigation of their plausible mechanisms of action.

This study aimed to characterize two types of postbiotics from Lactobacillus acidophilus LA-5 prepared in De Man, Rogosa, and Sharpe (MRS-Pb) and UF cheese whey (W-Pb). We compared the chemical compositions, functional properties, and toxicities of the prepared probiotics. Assessments included antimicrobial and antioxidant activities, total and individual phenolic compounds, volatile compounds, individual free amino acids, and organic acid contents. Cytotoxicity and potential effects on cell proliferation were assessed using MTT and wound healing assays in HCT-116 intestinal epithelial cancer cells. The results revealed differences in the chemical composition of the two postbiotics. Citric, lactic, and butyric acids were the main organic acids in W-Pb, whereas malic and acetic acids were the main organic acids in MRS-Pb. High levels of hydrocarbons were found in MRS-Pb. W-Pb exhibited potent antimicrobial activity against Listeria monocytogenes and Escherichia coli than MRS-Pb, while the antioxidant potential of MRS-Pb was higher than that of W-Pb. L. acidophilus postbiotics significantly reduced HCT-116 cell viability in a dose-dependent manner (10, 20, and 40 mg/mL for MRS-Pb and 10 and 20 mg/mL for W-Pb). MRS-Pb exhibited more potent effects and cytotoxicity than W-Pb did. Postbiotics did not affect HCT-116 cell proliferation or migration. Both postbiotics increased TAC in a concentration-dependent manner in treated cells, with MRS-Pb showing a stronger effect. These results suggest that the type of culture medium can significantly affect the bioactive properties, chemical composition, and toxicity of postbiotics.

The human body can be viewed as a combination of ecological niches inhabited by trillions of bacteria, viruses, fungi, and parasites, all united by the microbiota concept. Human health largely depends on the nature of these relationships and how they are built and maintained. However, personal hygiene practices have historically been focused on the wholesale elimination of pathogens and "hygiene-challenging microorganisms" without considering the collateral damage to beneficial and commensal species. The microbiota can vary significantly in terms of the qualitative and quantitative composition both between different people and within one person during life, and the influence of various environmental factors, including age, nutrition, bad habits, genetic factors, physical activity, medication, and hygienic practices, facilitates these changes. Disturbance of the microbiota is a predisposing factor for the development of diseases and also greatly influences the course and severity of potential complications. Therefore, studying the composition of the microbiota of the different body systems and its appropriate correction is an urgent problem in the modern world. The application of personal hygiene products or probiotics must not compromise health through disruption of the healthy microbiota. Where changes in the composition or metabolic functions of the microbiome may occur, they must be carefully evaluated to ensure that essential biological functions are unaffected. As such, the purpose of this review is to consider the microbiota of each of the "ecological niches" of the human body and highlight the importance of the microbiota in maintaining a healthy body as well as the possibility of its modulation through the use of probiotics for the prevention and treatment of certain human diseases.

Bacterial intra-kingdom communication involves the secretion of outer membrane vesicles as signaling carriers to the target cells. However, limited research exists on extracellular vesicles (EVs) from Gram-positive gut bacteria, their interactions with enteric pathogens, and potential inhibitory effects. In this study, we characterized the structure, protein content, and inhibitory effects of EVs from three new potential probiotic gut symbionts, Ligilactobacillus salivarius UO.C109, Ligilactobacillus saerimneri UO.C121, and Ligilactobacillus salivarius UO.C249. EVs were isolated and characterized using three different methods (ultracentrifugation, density gradient purification, and size exclusion chromatography). The purity, dose-dependency, structure, and proteome profiles of the purified EVs were evaluated. Antibacterial and anti-virulence activities of EV subpopulations were assessed against Salmonella enterica serovar Typhimurium and Campylobacter jejuni. EVs from Lg. salivarius UO.C109 and Lg. saerimneri UO.C121 showed inhibitory activity against S. Typhimurium, whereas EVs from Lg. salivarius UO.C249 inhibited the growth of C. jejuni. Notably, purified F3 fraction exhibited the highest inhibitory activity and was enriched in lysin motif (LysM)-containing proteins, peptidoglycan hydrolases, peptidoglycan recognition proteins (PGRPs), and metallopeptidases, which have been shown to play a prominent role in antimicrobial activities against pathogens. F3 had the highest concentration (73.8%) in the 80-90 nm size compared to the other fractions. Gene expression analysis revealed that EVs from Lg. salivarius UO.C109 and Lg. saerimneri UO.C121 downregulated adhesion and invasion factors in S. Typhimurium. Likewise, EVs from Lg. salivarius UO.C249 reduced pathogenicity gene expression in C. jejuni. This study highlighted the potential of gut bacterial EVs as therapeutic agents against enteric pathogens.

Celiac disease (CD) can be considered an autoimmune problem, a disease caused by gluten sensitivity in the body. Gluten is found in foods such as barley, wheat, and rye. This ailment manifests in individuals with hereditary susceptibility and under the sway of environmental stimulants, counting, in addition to gluten and intestinal microbiota dysbiosis. Currently, the only recommended treatment for this condition is to follow a gluten-free diet for life. In this review, we scrutinized the studies of recent years that focused on the use of postbiotics in vitro and in vivo in CD. The investigation of postbiotics in CD could be intriguing to observe their diverse effects on several pathways. This study highlights the definitions, characteristics, and safety issues of postbiotics and their possible biological role in the prevention and treatment of CD, as well as their application in the food and drug industry.

Chronic kidney disease (CKD) is a multifactorial disease affecting more than 13.4% of the world's population and is a growing public health problem. It is silent in its early stages and leads to irreversible kidney damage as the disease progresses. A key factor in this progression is the bidirectional relationship between CKD and gut dysbiosis, which creates an imbalance that promotes the accumulation of uremic toxins (UTs), contributing to renal fibrosis, endothelial dysfunction, and decreased glomerular filtration rate. In addition, CKD itself exacerbates gut dysbiosis by altering the composition of the gut microbiota (GM) and promoting the growth of pathogenic microorganisms. Therefore, it is crucial to explore new therapeutic strategies, and the use of probiotics and synbiotics has shown promise in modulating the GM. Numerous preclinical studies have shown that the use of probiotics in CKD has a beneficial effect on the kidney by reducing UTs, apoptosis, inflammation, and oxidative stress. Probiotic treatment has also been associated with restoration of intestinal integrity, modulation of microbial composition and diversity, and increased production of short-chain fatty acids (SCFAs). These positive results have also been observed in patients at different stages of CKD, where the use of probiotics and/or synbiotics was able to improve creatinine levels and uremic parameters and alleviate abdominal discomfort, in addition to modulating GM and reducing serum endotoxin levels. Although recent studies have explored the benefits of probiotics in the treatment of CKD, further research is needed to determine their long-term efficacy and clinical relevance. This review focuses on the factors driving gut dysbiosis in CKD, its role in disease progression, and the potential of probiotics as a therapeutic strategy.

The antibiotic overuse in hospitals, the food industry, and animal feed over past times has led to a significant rise in the incidence of antibiotic-resistant bacteria. To address these potentially life-threatening antibiotic-resistant illnesses, a quick identification and development of novel antimicrobials are necessary. The aim of this study was to synthesize a novel bacteriocin-nanoconjugates by combining selenium nanoparticles with purified bacteriocin from the Enterococcus faecium SMAA23 and investigate some of its biomedical activities. The nanoconjugates were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray desorption (EDX), and zeta potential analytical techniques. There is investigation of the antibacterial, antifungal, and anticancer properties of nanoconjugates. Purified bacteriocin has a known molecular weight of approximately 43,000 Daltons. The characterization of nanoparticles and nanoconjugates was performed. The crystallite size of nanoconjugate was determined via X-ray diffraction (XRD) to be 15.29 nm. Transmission electron microscopy (TEM) detected particles of irregular form of nanoconjugate, measuring between 11 and 24 nm in diameter. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of selenium and protein. The measured zeta potential was - 12.1 + 0.12 mV. The results revealed potent antibacterial activity against Acinetobacter baumannii, with a growth inhibition zone of 23 mm ± SD. A minimum inhibitory concentration (MIC) of nanoconjugate was 15.625 µg/mL, while a minimum bactericidal concentration (MBC) was 31.25 µg/mL. The application of scanning electron microscopy (SEM) enhanced the rupture of the bacterial cell wall. The antifungal activity against C. albicans and C. tropicalis resulted in growth inhibition zones of 14 mm and 16 mm (± SD), respectively. Various concentrations of the nanoconjugate strongly inhibited MDA-MB-231 cells in the MTT experiment. The novel synthesized bacteriocin-nanoconjugates exhibited substantial antibacterial, antifungal, and anticancer properties.