Resultados da aplicação tópica do extrato de própolis na redução da progressão da doença periodontal

RESUMO Agentes químicos têm sido usados para auxiliar na inibição da formação do biofilme e impedir desenvolvimento da doença periodontal (DP). O objetivo deste estudo foi avaliar radiograficamente a ação do extrato de própolis na progressão da DP induzida em ratos. Foram utilizados 48 ratos Wistar, divididos em 4 grupos (n=12): Controle, Pincel, Própolis e Clorexidina. Os grupos foram subdivididos para análise aos 7 e 21 dias. A progressão da DP foi avaliada radiograficamente pela distância entre a junção cemento-esmalte e a crista óssea alveolar na face mesial do 1º molar inferior. A perda óssea foi significativamente menor nos animais do grupo própolis em ambos os períodos (p ≤ 0,01). Concluiu-se por análise radiográfica que a aplicação tópica do extrato de própolis interfere reduzindo a progressão da doença periodontal induzida por ligadura em ratos, demonstrando a importância desse composto como substância auxiliar no tratamento periodontal

Exploring the impact of heat stress on feed efficiency in tropical beef cattle using genomic reaction norm models

Global climate change poses significant challenges to livestock production, particularly in tropical regions where cattle frequently experience heat stress (HS). HS negatively impacts feed efficiency by reducing feed intake, altering metabolic processes, and increasing energy requirements, leading to decreased animal performance. Understanding how cattle respond to environmental stressors is essential for improving efficiency by breeding programs. In this context, we investigated genotype-by-environment interaction (G × E) for dry matter intake (DMI) and residual feed intake (RFI) in Nellore cattle using bi-trait genomic reaction norm models and considering the temperature-humidity index (THI) as the environmental descriptor. Data from 22 838 animals collected between 2011 and 2023 across 21 Brazilian farms were analyzed. Meteorological data were obtained via NASA POWER, and THI values were calculated based on the average temperatures and relative humidity recorded during feed efficiency trials. Genomic data were available for 18 567 animals, and the genetic parameters were estimated using the single-step genomic best linear unbiased prediction approach. The genetic expression of feed efficiency traits was found to be influenced by climatic conditions, with heritability estimates for DMI (ranging from 0.22 to 0.39) and RFI (ranging from 0.08 to 0.28) varying across the THI gradient. Additionally, a reduction in additive genetic variance for both traits was observed under intense heat stress conditions, suggesting the important role of environmental factors on phenotypic variability of feed efficiency traits in Nellore cattle. The presence of G × E was more pronounced when THI exceeded 76, as genetic correlations for the same trait across different environmental gradients dropped below 0.80, leading to substantial sire reranking. Moreover, the genetic relationship between DMI and RFI also varied along the THI, with genetic correlations ranging from 0.64 to 0.72, highlighting alterations in the genetic expression of feed efficiency traits under different heat stress levels. These findings emphasize the need to consider genetic plasticity when selecting animals for improved feed efficiency in tropical regions. Overall, this study provides valuable insights for breeding programs aimed at improving beef cattle resilience to heat stress, ensuring sustainable production in the face of climate change

Update in Molecular Biology and Biotechnology: providing alternative for Sciences and Biology Teachers

One of the goals of the Coordination of Education and Dissemination of CBME is to contribute for the dissemination and the learning in Molecular Biology and Biotechnology in  all the educational levels. Thus, composing one of our actions in 2007, a course of update in Molecular Biology and Biotechnology directed to 21 teachers of Sciences and Biology of São Carlos (SP, Brazil) was carried through, totalizing 24 hours. In one of the meetings, we presented the techniques involving restriction enzymes, gel electrophoresis and its applications, followed of an experimental activity. Also we constructed and  considered the use, for the teachers, of a macroscopic model of a gel box that would represent the displacement of DNA fragments. After that a written questionnaire was used to evaluate the importance attributed for the teachers to the subject, the possibilities of didactic transposition, as well as their interests for other activities that would deal this thematic at great length. From this,  we registered that the 93% of the teachers showed interest in the subject, considering it important and also, 79% of them affirmed to have possibility of didactic transposition of this subject after they have experienced the course. On the other hand, 86% of the teachers did not work the subject in their classes , amongst which 50% for the lack of time or not enough preparation. Therefore, the data suggest that the course had an impact on the vision of the teachers concerning the alternatives to include the subject Molecular Biology and Biotechnology in their curricular planning