جستجوی مقالات مرتبط با کلیدواژه « peptides » در نشریات گروه « پزشکی »

Peptides from lactic acid bacteria provide health benefits and can inhibit the growth of pathogenic organisms. The present work aimed to isolate and characterize peptides with antibacterial activity from Lactobacillus plantarum 1407.

Peptides were isolated and purified from L. plantarum 1407. The effect of various physiological parameters on the antibacterial activity of the isolated peptides was analyzed. The mode of action of the peptides on indicator organisms was observed using transmission microscopy analysis and flow cytometry analysis .

Antibacterial activity and mode of action of peptides isolated from L. plantarum 1407 against gram-positive and gram-negative bacteria have been studied. L. plantarum culture exhibited maximum antibacterial activity at 40 °C, pH 8, and 0.7% salt concentration. The cell-free supernatant (CFS) was concentrated using a 3 kDa ultrafiltration membrane and the peptide fractions (<3 kDa) were further fractionated using Sephadex G-25 gel filtration chromatography. The antibacterial activity of the eluted fractions (F1 to F4) was evaluated using flow cytometry and transmission electron microscopy. F3 fraction exhibited increased antibacterial activity than F1, F2, and F4 fractions against the indicator organisms. Cell membrane damage and leakage of cytoplasmic content of the bacterial cells treated with the antibacterial F3 fraction peptides were observed.

The active peptides from L. plantarum 1407 can be potentially used for the treatment of bacterial infections.

Proteins and peptides have secured a place as excellent therapeutic moieties on account of their high selectivity and efficacy. However due to oral absorption limitations, current formulations are mostly delivered parenterally. Oral delivery of peptides and proteins (PPs) can be considered the need of the hour due to the immense benefits of this route. This review aims to critically examine and summarize the innovations and mechanisms involved in oral delivery of peptide and protein drugs.

Comprehensive literature search was undertaken, spanning the early development to the current state of the art, using online search tools (PubMed, Google Scholar, ScienceDirect and Scopus).

Research in oral delivery of proteins and peptides has a rich history and the development of biologics has encouraged additional research effort in recent decades. Enzyme hydrolysis and inadequate permeation into intestinal mucosa are the major causes that result in limited oral absorption of biologics. Pharmaceutical and technological strategies including use of absorption enhancers, enzyme inhibition, chemical modification (PEGylation, pro-drug approach, peptidomimetics, glycosylation), particulate delivery (polymeric nanoparticles, liposomes, micelles, microspheres), site-specific delivery in the gastrointestinal tract (GIT), membrane transporters, novel approaches (self-nanoemulsifying drug delivery systems, Eligen technology, Peptelligence, self-assembling bubble carrier approach, luminal unfolding microneedle injector, microneedles) and lymphatic targeting, are discussed. Limitations of these strategies and possible innovations for improving oral bioavailability of protein and peptide drugs are discussed.

This review underlines the application of oral route for peptide and protein delivery, which can direct the formulation scientist for better exploitation of this route.

Early detection of breast cancer (BC) is extremely important as late diagnosis has been associated with a high rate of mortality. Immunogenic proteins and autoantibodies have been considered as favorable targets for early detection and targeted therapy in cancer. Accordingly, the present study aimed to identify the immunogenic antigens in both early and advanced stages of BC via a serologic proteome analysis (SERPA) approach.

This is a case-control study wherein we separated the proteins from BC tissues in the early stages (n = 10) and advanced stages (n = 10) utilizing two-dimensional electrophoresis (2DE) and then transferred them onto a Polyvinylidene Difluoride (PVDF) membrane. To explore the tumor antigens reacting with antibodies, two-dimensional (2D) blots of tumor tissues in the early and advanced stages were separately probed with the sera from the same patients. Afterwards, we identified antibody-reactive proteins via liquid chromatography with tandem mass spectrometry (LC-MS/MS).

Fibrinogen beta chain (FGB), protein deglycase DJ-1(PARK7), and peroxiredoxin-2 (PRDX2) were the highly reactive antigens identified in the earlystage patients. In addition, RuvB-like1 (RUVBL1) and triose phosphate isomerase (TPI) were recognized as the immune reactive proteins in the late-stage patients.

The results herein revealed that the immune-proteome pattern of BC patients changes along with tumor progression from primary to advanced stages. Moreover, immunogenic proteins seemed to stimulate the humoral immune system to produce autoantibodies in the initiation phase of BC; these autoantibodies could be employed as complementary factors for early detection of BC. The findings are however preliminary, and further studies with a larger sample size are required for verification and validation of previous findings.

salivary proteins have, today, gained special importance in studies of the role of saliva in tooth decay. Among the peptides, histatins and defenses play a more important role. The aim of this study was to determine the concentration of salivary antibacterial peptides in children with early childhood caries (ECC, SECC) compared to children without caries.

This comparative-case study was conducted on 48 young children (under 6 years of age) with milk teeth referred to a private pediatric dentistry center. The participants were divided into three groups of 16 with early childhood caries (ECC, SECC) and without decay. After collecting children's saliva, the samples were sent to the laboratory to obtain peptide concentration in salivia using ELISA and the results were analyzed using SPSS 22 software.

The average index of histatin-5 in the mild caries group was significantly lower than those in the moderate caries (p<0.001) and severe caries groups (p<0.001). The average index of beta-defensin-1 in the mild caries group was significantly higher than those in the moderate caries (p<0.001) and severe caries groups (p<0.001). The average beta-defensin-2 index in the mild caries group was significantly higher than those in the moderate caries group (p<0.001); and in the severe caries group, it was significantly higher than that in the moderate caries group (p<0.001).

With the increase of salivary HST-5, the progress of caries increased. Also, the progress of caries was associated with a decrease in the amount of β-defensin-1. No correlation was observed between the caries process and the amount of β-defensin-2.

 The rise of antibiotic resistance has become a major concern, signaling the end of the golden age of antibiotics. Bacterial biofilms, which exhibit high resistance to antibiotics, significantly contribute to the emergence of antibiotic resistance. Therefore, there is an urgent need to discover new therapeutic agents with specific characteristics to effectively combat biofilm-related infections. Studies have shown the promising potential of peptides as antimicrobial agents.

 This study aimed to establish a cost-effective and streamlined computational method for predicting the antibiofilm effects of peptides. This method can assist in addressing the intricate challenge of designing peptides with strong antibiofilm properties, a task that can be both challenging and costly.

 A positive library, consisting of peptide sequences with antibiofilm activity exceeding 50%, was assembled, along with a negative library containing quorum-sensing peptides. For each peptide sequence, feature vectors were calculated, while considering the primary structure, the order of amino acids, their physicochemical properties, and their distributions. Multiple supervised learning algorithms were used to classify peptides with significant antibiofilm effects for subsequent experimental evaluations.

 The computational approach exhibited high accuracy in predicting the antibiofilm effects of peptides, with accuracy, precision, Matthew's correlation coefficient (MCC), and F1 score of 99%, 99%, 0.97, and 0.99, respectively. The performance level of this computational approach was comparable to that of previous methods. This study introduced a novel approach by combining the feature space with high antibiofilm activity.

 In this study, a reliable and cost-effective method was developed for predicting the antibiofilm effects of peptides using a computational approach. This approach allows for the identification of peptide sequences with substantial antibiofilm activities for further experimental investigations. Accessible source codes and raw data of this study can be found online (hiABF), providing easy access and enabling future updates.

Bacteriocins are small peptides which are ribosomally synthesized and have been shown to have wide range of antimicrobial activity. The aim of this study was to optimize the production of L. paracasei MG847589 bacteriocin. Furthermore, the potential antibacterial properties of the novel bacteriocins were characterized and evaluated against Staphylococcus aureus.

The present study optimized the growth media constituents of Lactobacillus paracasei MG847589 to improve bacteriocin yield by applying One-Factor-at-a-Time (OFAT) and Response Surface Methodology (RSM) methods.

At OFAT, two-fold activity increased against Staphylococcus aureus in the presence of whey (22.5 g/L) as nitrogen source and sucrose (30 g/L) as carbon source. RSM tool was performed with media compounds using design expert 12.0.1.0. Whey (22.5 g/L), sucrose (30 g/L), temperature (30 ºC), and pH (6.5) condition yielded 25,600 AU/ml of bacteriocin against S. aureus. Bacteriocin was stable at pH range of 2.0 to 8.0 for one h and at 60 ºC for 15 min. The produced antimicrobial peptide is a novel bacteriocin with molecular mass of 2,611.122 Da.

Bacteriocin of L. paracasei MG847589 isolated from traditional Egyptian cheese (Kareish) showed great antimicrobial activity and could be applied as food preservative in food manufacturing.

The relationship between the biochemical characteristics of follicular fluid (FF), oocyte quality and embryonic development has not yet been elucidated. We compared samples of FF with a normal metabolic profile against samples with metabolic abnormalities to identify potential predictive biomarkers of reproductive success.

To analyze peptide activity in the FF of women undergoing in vitro fertilization using 3 samples of FF per individual.

FF samples were obtained by ovum pick-up. Pathological samples were defined as samples of FF obtained from women with a gynecological condition or with infertility. A total of 30 women participated in this study. 3 samples of FF were obtained per individual (90 samples), but 8 samples were excluded because they were hemolyzed. The samples (n = 82 FF) included controls (n = 36, donors without fertility problems), women with endometriosis (n = 15), unexplained infertility (n = 19), and aged > 39 (n = 12). We assessed local encephalinergics: aminopeptidase-N (puromycin sensitive aminopeptidase and neutral endopeptidase; and components of the angiotensin system of the reproductive tract: prolyl-endopeptidase, APN, aspartate-aminopeptidase, and basic-aminopeptidase.

No differences were observed in peptide metabolism based on the presence or absence of oocytes in the FF. Women with endometriosis and aged > 39 yr showed alterations in puromycin sensitive aminopeptidase (p = 0.01), aminopeptidase-B (p = 0.01), aspartate-aminopeptidase (p < 0.001) and neutral endopeptidase (p < 0.001).

This study reveals alterations in the metabolism of enkephalin and angiotensin in pathological FF, which points to these components as potential diagnostic biomarkers.

Since the appearance of acquired immunodeficiency syndrome(AIDS) disease, millions of people got infected, thousands are died and many suffered from its complications. One of the chronic and late symptoms of AIDS is lipodystrophy that leads to losing of fat in some parts of the body while gaining it at other organs and sites. One of the main targets in drug development for management of lipodystrophy is growth hormone-releasing hormone (GHRH) receptor. As a secondary metabolite from plants, leginsulin is a peptide with 37 amino acids and considered as hormone-like peptide. In this study, through in silico approaches, binding of leginsulin and GHRH receptor was studied. The results showed strong binding of the two molecules with docking score of -324.16 and ligand RMSD of 47.26. The molecular dynamic investigation also revealed these two proteins remained bound for almost 104 ns. Evaluation of the peptide toxicity in the body had shown that it is not toxic to the human organs and also, it doesn’t pass through the blood brain barrier. The results support the use of legumes as a source of leginsulin for potential management of lipodystrophy in the patients with AIDS.

Nosocomial infections caused by Acinetobacter baumannii (A. baumannii) nosocomial infections caused by Acinetobacter baumannii (A. baumannii) are considered as a global serious problem in hospitalized patients because of emerging antibiotic resistance. Immunotherapy approaches are promising to prevent such infections. In our previous study, five antigenic epitopes of outer membrane protein A (OmpA), as the most dangerous virulence molecule in A. baumanii, were predicted in silico. In this study, the investigators evaluated some immunological aspects of the peptides. Five peptides were separately injected into C5BL/6 mice; then the cytokine production (interleukin-4 and interferon-gamma) of splenocytes and opsonophagocytic activity of immunized serum were assessed. To identify the protective function of the peptides, animal models of sepsis and pneumonia infections were actively and passively immunized with selected peptides and pooled sera of immunized mice, respectively. Then, survival rates of them were compared with the non-infected controls. Based on the results, activated spleen cells in P127 peptide-immunized mice exhibited an increase level of IFN-γ compared with the other experimental groups, but not about the IL-4 concentration. The results of opsonophagocytic assay revealed an appropriate killing activity of produced antibodies against A. baumannii in a dose-dependent manner. Further, the survival rates of the mice under passive immunization with the immunized sera or active immunization with P127 peptide were significantly more than those in the control group. Moreover, the survival rate of the P127 peptide immunized group was considerably higher than that among the other peptide-immunized group. In conclusion, findings indicated that peptides derived from outer membrane protein-A can be used as a promising tool for designing the epitope-based vaccines against infections caused by A. baumannii.