Anti-Staphy peptides rationally designed from Cry10Aa bacterial protein.

Bacterial infections pose a significant threat to human health, constituting a major challenge for healthcare systems. Antibiotic resistance is particularly concerning in the context of treating staphylococcal infections. In addressing this challenge, antimicrobial peptides (AMPs), characterized by their hydrophobic and cationic properties, unique mechanism of action, and remarkable bactericidal and immunomodulatory capabilities, emerge as promising alternatives to conventional antibiotics for tackling bacterial multidrug resistance. This study focuses on the Cry10Aa protein as a template for generating AMPs due to its membrane-penetrating ability. Leveraging the Joker algorithm, six peptide variants were derived from α-helix 3 of Cry10Aa, known for its interaction with lipid bilayers. In vitro, antimicrobial assays determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) required for inhibiting the growth of Staphylococcus aureus, Escherichia coli, Acinetobacter baummanii, Enterobacter cloacae, Enterococcus facallis, Klebsiella pneumonia, and Pseudomonas aeruginosa. Time-kill kinetics were performed using the parental peptide AMPCry10Aa, as well as AMPCry10Aa_1 and AMPCry10Aa_5, against E. coli ATCC, S. aureus 111 and S. aureus ATCC strains showing that AMPCry10Aa_1 and AMPCry10Aa_5 peptides can completely reduce the initial bacterial load with less than 2 h of incubation. AMPCry10Aa_1 and AMPCry 10Aa_5 present stability in human serum and activity maintenance up to 37 °C. Cytotoxicity assays, conducted using the MTT method, revealed that all of the tested peptides exhibited cell viability >50% (IC50). The study also encompassed evaluations of the structure and physical-chemical properties. The three-dimensional structures of AMPCry10Aa and AMPCry10Aa_5 were determined through nuclear magnetic resonance (NMR) spectroscopy, indicating the adoption of α-helical segments. Electron paramagnetic resonance (EPR) spectroscopy elucidated the mechanism of action, demonstrating that AMPCry10Aa_5 enters the outer membranes of E. coli and S. aureus, causing substantial increases in lipid fluidity, while AMPCry10Aa slightly increases lipid fluidity in E. coli. In conclusion, the results obtained underscore the potential of Cry10Aa as a source for developing antimicrobial peptides as alternatives to conventional antibiotics, offering a promising avenue in the battle against antibiotic resistance

Neural network applications to the rainfall rate extraction in the presence of attenuation

The paper addresses the problem of the reconstruction of the rainfall field using weather radar observables. It is well known that at the C band and especially at the X band the reconstruction of the rainfall rate profile along the range using absolute (Z(H)) and differential (Z(DR)) reflectivity measurements is significantly affected by the attenuation coefficients (i.e. alpha(H) and alpha(D)). This problem has been long and extensively studied and iterative attenuation correction techniques based on a cumulative procedure were developed, in which the attenuation at n(th) cell is estimated using the attenuation corrected reflectivity values at previous cell. Usually the attenuation coefficients (alpha(H), alpha(D)) are estimated using non linear parametrizations with (Z(H), Z(DR)), or, if phase measurements are available, using linear parametrizations with the specific differential phase shift K-DP In this work novel approaches based on neural networks (N.N.) have been used.First, to estimate (alpha(H), alpha(D)) from Z(H), Z(DR) and K-DP; the N.N. estimators have shown better performance (often, slightly better) in comparison to the best ones known.Second, N.N. have been implemented to extract the range rainfall rate profile. The input to the network is a vector containing the attenuated measurements of Z(H), Z(DR) and K-DP in a number of range cells while the output is the estimated profile of the rainfall rate. In this way a global compensation of the attenuation is implemented. (C) 2000 Elsevier Science Ltd. All rights reserved

Angiomatoid melanoma: a dermoscopic and pathologic challenge.

Melanoma (MM) can show different clinic-pathologic features. Several rare forms of MM have been described, including angiomatoid MM (AMM).Few cases of AMM have been described in the literature. Furthermore, in none of them a dermoscopic description has been reported. Because of its vascular appearance, AMM can mimic dermoscopically several cutaneous lesions, including vascular lesions and non-melanoma skin cancers, such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and angiosarcoma