Antimicrobial peptides are widely recognized as an excellent alternative to conventional antibiotics. MSI-78, a highly effective and broad spectrum AMP, is one of the most promising AMPs for clinical application. In this study, we have designed shorter derivatives of MSI-78 with the aim of improving selectivity while maintaining antimicrobial activity. Shorter 17-mer derivatives were created by truncating MSI-78 at the N-and/or C-termini, while spanning MSI-78 sequence. Despite the truncations made, we found a 17-mer peptide, MSI-78(4−20) (KFLKKAKKFGKAFVKIL), which was demonstrated to be as effective as MSI-78 against the Gram-positive Staphylococcus strains tested and the Gram-negative Pseudomonas aeruginosa. This shorter derivative is more selective toward bacterial cells as it was less toxic to erythrocytes than MSI-78, representing an improved version of the lead peptide. Biophysical studies support a mechanism of action for based on the disruption of the bacterial membrane permeability barrier, which in turn leads to loss of membrane integrity and ultimately to cell death. These features point to a mechanism of action similar to the one described for the lead peptide MSI-78.
Antimicrobial peptides (AMPs) are a class of broad-spectrum antibiotics known by their ability to disrupt bacterial membranes and their low tendency to induce bacterial resistance, arising as excellent candidates to fight bacterial infections. In this study we aimed at designing short 12-mer AMPs, derived from a highly effective and broad spectrum synthetic AMP, MSI-78 (22 residues), by truncating this peptide at the N- and/or C-termini while spanning its entire sequence with 1 amino acid (aa) shifts. These designed peptides were evaluated regarding antimicrobial activity against selected gram-positive Staphylococcus strains and the gram-negative Pseudomonas aeruginosa (P. aeruginosa). The short 12-mer peptide CEM1 (GIGKFLKKAKKF) was identified as an excellent candidate to fight P. aeruginosa infections as it displays antimicrobial activity against this strain and selectivity, with negligible toxicity to mammalian cells even at high concentrations. However, in general most of the short 12-mer peptides tested showed a reduction in antimicrobial activity, an effect that was more pronounced for gram-positive Staphylococcus strains. Interestingly, CEM1 and a highly similar peptide differing by only one aa-shift (CEM2: IGKFLKKAKKFG), showed a remarkably contrasting AMP activity. These two peptides were chosen for a more detailed study regarding their mechanism of action, using several biophysical assays and simple membrane models that mimic the mammalian and bacterial lipid composition. We confirmed the correlation between peptide helicity and antimicrobial activity and propose a mechanism of action based on the disruption of the bacterial membrane permeability barrier.
Limit state design applied to geotechnical structures requires the selection of characteristic values of ground parameters and the use of partial safety factors. These factors, and the way that characteristic values are selected, will govern the calculated probability of failure of the structure. The paper presents a methodology for estimating the probability of failure provided by the application of Eurocode 7 to the design of spread foundations and embankments. A parametric study is presented enabling the identification of the reduction factors by which the mean value of soil resistance parameters should be multiplied to obtain the characteristic value that will ensure a target probability of failure.
In early life, maternal factors are of the utmost relevance for oral microbiome acquisition and maturation. Therefore, our study explored the impact of maternal factors, such as saliva and breastmilk colonization, cardiovascular risk factors (CRF), type of delivery, oral health, and caregiving habits on the prevalence of potential pathogenic and opportunistic oral bacteria in early life. A total of 26 healthy mothers, 23 mothers with CRF, and their 50 children were included and samples (child’s oral swabs, mother’s saliva, and breastmilk) were collected 4 to 12 weeks after delivery and inoculated in selective and differential media for detection of non-fastidious Gram-negative and Gram-positive bacteria to isolate potential pathogenic and opportunistic bacteria identified by MALDI-TOF MS (414 isolates). Within mother–child dyads, the same species were identified in 86% of the pairs and potential pathogenic microorganisms from the Staphylococcaceae and Enterobacteriaceae families were found to be statistically significantly concordant between mother–child samples, particularly in the healthy group. Staphylococcus saprophyticus and Stenotrophomonas maltophilia oral colonization in mother–child pairs were associated with the presence of CRF. Breastfeeding was related to the early life oral colonization of Staphylococcus epidermidis in children from healthy mothers and C-section was associated with higher diversity of pathogens, independent of cardiovascular status (p = 0.05). This study reveals the presence of potential oral opportunistic and pathogenic bacteria in early life and highlights the importance of maternal factors in its acquisition.
Toxoplasma gondii is a parasite capable of infecting humans and other warm-blooded animals, that it is estimated to have chronically infected a third of the world population. While mostly asymptomatic in immunocompetent patients, it is considered a serious disease in immunocompromised patients, with potentially fatal consequences. The current treatment method used can trigger numerous negative side effects. The aim of this review is to evaluate current studies available regarding potential new candidates to be used against Toxoplasma gondii.
As one of the three leading causes of death in people between the ages of 15 and 44 years old, suicide is, according to data from WHO, responsible annually for a million deaths. These numbers do not include suicide attempts, that are usually 10 to 20 times more frequent than suicide itself. This systematic review proposes to gather relevant information on the topic of self-harm and suicide in the Army, following the PRISMA-P statement for systematic review and meta-analysis protocols. This systematic review protocol was developed to present suitable guidelines for the development of research that can provide results to fulfil the sought objective. The search will cover the dates between 2014 and May 2019. Five databases will be accessed (SCOPUS, PubMed, Science Direct, EBSCOhost and Web of Science) with a total of six keyword combinations. The Cochrane Collaboration Tool will assess study selection and quality for determining the risk of bias.
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