A number of research have proven that antimicrobial peptides are of greatest potential as a new class of antibiotics. Antimicrobial peptides and cell-penetrating peptides share some similar structure characteristics. In our study, a new peptide analog, APP (GLARALTRLLRQLTRQLTRA) from the cell-penetrating peptide ppTG20 (GLFRALLRLLRSLWRLLLRA), was identified simultaneously with the antibacterial mechanism of APP against Salmonella typhimurium and Streptococcus pyogenes. APP displayed potent antibacterial activity against Gram-negative and Gram-positive strains. The minimum inhibitory concentration was in the range of 2 to 4 μM. APP displayed higher cell selectivity (about 42-fold increase) as compared to the parent peptide for it decreased hemolytic activity and increased antimicrobial activity. The calcein leakage from egg yolk L-α-phosphatidylcholine (EYPC)/egg yolk L-α-phosphatidyl-DL-glycerol and EYPC/cholesterol vesicles demonstrated that APP exhibited high selectivity. The antibacterial mechanism analysis indicated that APP induced membrane permeabilization in a kinetic manner for membrane lesions allowing O-nitrophenyl-β-D-galactoside uptake into cells and potassium release from APP-treated cells. Flow cytometry analysis demonstrated that APP induced bacterial live cell membrane damage. Circular dichroism, fluorescence spectra, and gel retardation analysis confirmed that APP interacted with DNA and intercalated into the DNA base pairs after penetrating the cell membrane. Cell cycle assay showed that APP affected DNA synthesis in the cell. Our results suggested that peptides derived from the cell-penetrating peptide have the potential for antimicrobial agent development, and APP exerts its antibacterial activity by damaging bacterial cell membranes and binding to bacterial DNA to inhibit cellular functions, ultimately leading to cell death.

No abstract

We investigated the antifungal properties and anti-candidal mechanism of antimicrobial peptide APP. The minimum inhibitory concentration of APP was 8 μM against Candida albicans and Aspeogillus flavus, the concentration against Saccharomyces cerevisiae and Cryptococcus neoformans was 16 μM, while 32 μM inhibited Aspergilla niger and Trichopyton rubrum. APP caused slight depolarization (12.32 ± 0.87%) of the membrane potential of intact C. albicans cells when it exerted its anti-candidal activity and only caused 21.52 ± 0.48% C. albicans cell membrane damage. APP interacted with cell wall membrane, caused potassium efflux and nucleotide leakage. However, confocal fluorescence microscopy experiment and flow cytometry confirmed that FITC-labeled APP penetrated C. albicans cell membrane with 52.31 ± 1.88% cell-penetrating efficiency and accumulated in the cytoplasm. Then, APP interact with C. albicans genomic DNA and completely suppressed DNA migration above weight ratio (peptide/DNA) of 2, and significantly arrested cell cycles during the S-phase (S-phase cell population was 27.09 ± 0.73%, p < 0.05) after penetrating the cell membrane. Results indicated that APP kills C. albicans for efficient cell-penetrating efficiency, strong DNA-binding affinity and significant physiological changes inducing S-phase arrest in intracellular environment.

No abstract

BackgroundEmpirical evidence on the link between agrobiodiversity and dietary diversity appears to be inconclusive. Thus, there arises a need to determine other factors that could significantly influence dietary diversity in different agro-ecological zones, as factors may vary from region to region.ObjectiveThe objective of this study was to document the status of agrobiodiversity and dietary diversity and to assess the determinants of dietary diversity among women of reproductive age in two different agro-ecological zones of Rongai Sub-County in Kenya.DesignA cross-sectional study of 384 women aged 18–49 years was conducted. Agrobiodiversity was measured using the Shannon-Wiener index, species richness (count) and production diversity score. A 24-hour dietary recall was used to determine minimum dietary diversity for women (MDD-W) of reproductive age.ResultsAlthough the level of agrobiodiversity was different between the low and high agro-ecological zones (using Shannon-Wiener index); the women’s dietary diversity was not different (p > 0.05) between low (3.78 ± 0.99) and high potential areas (3.84 ± 1.05). In multivariate logistic regression, there was no association (p > 0.05) between agrobiodiversity indicators and dietary diversity across the two agricultural zones. Factors influencing MDD-W in two agricultural zones were different. In low potential areas, woman’s education level positively determined dietary diversity, while in high potential areas household gender, woman’s education level, woman’s age and family size influenced MDD-W.ConclusionThe proportion of women who met minimum dietary diversity was low. Although agrobiodiversity was different in the two agro-ecological zones, women’s dietary diversity scores were similar. In low agricultural potential areas, only education level influenced women’s dietary diversity while household gender, education level, age and family size were the important determinants in high agricultural potential areas. Therefore, it is recommended that nutrition interventions focusing on lessening malnutrition and improving dietary quality should pay special attention to differences in agro-ecological zones to develop region-specific interventions instead of generalizing interventions.

No abstract

No abstract

No abstract