A molecular switch modulates assembly and host factor binding of the HIV-1 capsid.

The HIV-1 capsid is a fullerene cone made of quasi-equivalent hexamers and pentamers of the viral CA protein. Typically, quasi-equivalent assembly of viral capsid subunits is controlled by a molecular switch. Here, we identify a Thr-Val-Gly-Gly motif that modulates CA hexamer/pentamer switching by folding into a 310 helix in the pentamer and random coil in the hexamer. Manipulating the coil/helix configuration of the motif allowed us to control pentamer and hexamer formation in a predictable manner, thus proving its function as a molecular switch. Importantly, the switch also remodels the common binding site for host factors that are critical for viral replication and the new ultra-potent HIV-1 inhibitor lenacapavir. This study reveals that a critical assembly element also modulates the post-assembly and viral replication functions of the HIV-1 capsid and provides new insights on capsid function and inhibition.

Streptococcus agalactiae in pregnant women in Brazil: prevalence, serotypes, and antibiotic resistance.

Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the Federal Brazilian Health Authorities describing guidelines and protocols to perform GBS screening in pregnant women, in both public and private clinics. In the present review, we evaluated published reports addressing the prevalence of GBS in different regions of the country, methods used, and, when available, information regarding antibiotic resistance and serological typing of clinical isolates. According to this review, GBS prevalence in pregnant women in Brazil ranged from 4.2 to 28.4%, in the last 10 years. Serotype Ia was the most prevalent. The highest antibiotic resistance rates were found for tetarcycline, although its use to treat GBS infections is not common. Our results also show high resistance rates to clindamycin and erythromycin, which are commonly used as an alternative to penicillin in GBS infecctions. The increased antibiotic resistance, variations in serotype distribution, and high GBS prevalences need to be further investigated. Based on the present situation, recommendations regarding GBS surveillance in the country were raised and may improve our strategies for preventing neonatal infections.

Functional oils affect blood and bacteriological parameters in sheep / Los aceites funcionales afectan parámetros sanguíneos y bacteriológicos en ovinos / Óleos funcionais afetam parâmetros sanguíneos e bacteriológicos em ovinos

Abstract Background: Feeding ionophores to sheep is intended for improving feed efficiency. Functional oils (FO) are an alternative to the use of ionophores. Objective: To evaluate the effect of feeding FO to sheep on blood parameters and fecal bacteria. Methods: Five sheep were used in a Latin square design with five treatments: 190, 285, 380, 570, and 675 g/t FO in the diet. White cell count and levels of blood glucose, total protein, urea nitrogen, and fecal bacteria presence in feces were determined. Results: The FO levels did not affect serum parameters. Salmonella spp was found only in feces of sheep fed 190 mg/t FO. Conclusion: Functional oils can be added to sheep diets to reduce the presence of Salmonella spp in the feces.

Resumen Antecedentes: Los ionóforos se suministran a los ovinos para mejorar la eficiencia alimenticia. Una alternativa al uso de ionóforos son los aceites funcionales (FO). Objetivo: Evaluar los efectos del suministro de FO en el alimento sobre los parámetros sanguíneos y bacterias fecales de ovinos. Métodos: Cinco ovejos fueron usados en un diseño de cuadrado latino con cinco tratamientos: 190, 285, 380, 570 y 675 g/t FO en la dieta. Se realizó conteo de leucocitos y niveles de glucosa, proteína total y nitrógeno ureico, y se determinó la presencia de bacterias fecales. Resultados: La inclusión dietaria de FO no afectó los parametros séricos. Se encontró Salmonella spp únicamente en heces de los ovinos que habían consumido 190 mg/t FO. Conclusión: Se puede agregar FO a la dieta de ovinos para reducir la presencia de Salmonella spp en heces.

Resumo Antecedentes: Na produção animal, ionóforos são ingeridos por ovinos para melhorar a eficiência alimentar. Alternativa ao uso de ionóforos são os óleos funcionais (FO). Objetivos: Avaliar os efeitos de FO em ovinos por meio da alimentação sobre os parâmetros sanguíneos e bacteriológicos. Métodos: Cinco ovinos foram usados em Quadrado Latino com cinco tratamentos: 190, 285, 380, 570 e 675 g/t FO nas dietas. Contagem de leucócitos e níveis de glicose, proteína total, nitrogênio ureico e presença de bactérias nas fezes foram determinados. Resultados: Os níveis de FO não afetaram os níveis séricos dos fatores mencionados. Salmonella spp foi encontrada somente em fezes de ovinos que haviam ingerido dietas com 190 mg/t FO. Conclusão: Óleos funcionais podem ser adicionados em dietas para ovinos para reduzir a presença de Salmonella spp nas fezes.