Potential therapeutic use of dermaseptin S4 from the frog Phyllomedusa sauvagii and its derivatives against bacterial pathogens in fish.

AIM: Dermaseptins are one of the main families of antimicrobial peptides (AMPs) derived from the skin secretions of Hylidae frogs. Among them, dermaseptin S4 (DS4) is characterized by its broad-spectrum of activity against bacteria, protozoa, and fungi. In this study, the physicochemical properties of the native peptide DS4 (1-28) and two derivatives [DS4 (1-28)a and DS4 (1-26)a] isolated from the skin of the frog Phyllomedusa sauvagii were investigated and their antimicrobial properties against two marine pathogenic bacteria (V. harveyi and V. anguillarum) were examined. METHODS AND RESULTS: The results indicate that the peptide DS4 (1-26)a has high antibacterial activity against the tested strains and low hemolytic activity (< 30% lysis at the highest tested concentration of 100 µg mL -1) compared to the other two peptides tested. In addition, all three peptides affect the membrane and cell wall integrity of both pathogenic bacteria, causing leakage of cell contents, with DS4 (1-26)a having the most severe impact. These skills were corroborated by transmission electron microscopy and by the variation of cations in their binding sites due to the effects caused by the AMPs. CONCLUSIONS: These results suggest that DS4 and its derivatives, in particular the truncated and amidated peptide DS4 (1-26)a could be effective in the treatment of infections caused by these marine pathogenic bacteria. Future studies are required to validate the use of DS4  in vivo for the prevention of bacterial diseases in fish.

Highly Accurate Chip-Based Resequencing of SARS-CoV-2 Clinical Samples.

SARS-CoV-2 has infected over 128 million people worldwide, and until a vaccine is developed and widely disseminated, vigilant testing and contact tracing are the most effective ways to slow the spread of COVID-19. Typical clinical testing only confirms the presence or absence of the virus, but rather, a simple and rapid testing procedure that sequences the entire genome would be impactful and allow for tracing the spread of the virus and variants, as well as the appearance of new variants. However, traditional short read sequencing methods are time consuming and expensive. Herein, we describe a tiled genome array that we developed for rapid and inexpensive full viral genome resequencing, and we have applied our SARS-CoV-2-specific genome tiling array to rapidly and accurately resequence the viral genome from eight clinical samples. We have resequenced eight samples acquired from patients in Wyoming that tested positive for SARS-CoV-2. We were ultimately able to sequence over 95% of the genome of each sample with greater than 99.9% average accuracy.

Presencia de Helicobacter pylori en la mucosa gástrica de cadáveres / Helicobacter pylori in the gastric mucosa if violently deceased adults

Se estudiaron 50 cadáveres de adultos que fallecieron en forma violenta y no recibieron tratamiento para el hecho que los llevó a la muerte. Se tomaron muestras de cuerpo y antro gástricos, se preservaron en formol al 10 por ciento, se incluyeron en parafina y se colorearon con hematoxilina- eosina y tinción de Warthin Starry. Se encontró que el 92 por ciento de las muestras fueron positivas para H. pylori y que 6 por ciento de ellas no mostraban cambios inflamatorios de la mucosa gástrica. Se observó una clara asociación entre H. pylori y cambios de gastritis.

ABSTRACT We studied the stomachs of 50 adults who died in a violent way and did not receive any treatment before death. Specimens were obtained from the gastric mucosa of body and antrum; after standard tissue processing they were stained with Hematoxilin-Eosin and by the Warthin. Starry method. Forty one specimens (82%) were positive for H. pylori and 3 of them showed no inflammatory changes. There was a clear association between the presence of H. pylori and