BackgroundGenetic resistance in cattle is considered a suitable way to control tick burden and its consequent losses for livestock production. Exploring tick-resistant (R) and tick-susceptible (S) hosts, we investigated the genetic mechanisms underlying the variation of Braford resistance to tick infestation. Skin biopsies from four-times-artificially infested R (n = 20) and S (n = 19) hosts, obtained before the first and 24 h after the fourth tick infestation were submitted to RNA-Sequencing. Differential gene expression, functional enrichment, and network analysis were performed to identify genetic pathways and transcription factors (TFs) affecting host resistance.ResultsIntergroup comparisons of hosts before (Rpre vs. Spre) and after (Rpost vs. Spost) tick infestation found 51 differentially expressed genes (DEGs), of which almost all presented high variation (TopDEGs), and 38 were redundant genes. Gene expression was consistently different between R and S hosts, suggesting the existence of specific anti-tick mechanisms. In the intragroup comparisons, Rpost vs. Rpre and Spost vs. Spre, we found more than two thousand DEGs in response to tick infestation in both resistance groups. Redundant and non-redundant TopDEGs with potential anti-tick functions suggested a role in the development of different levels of resistance within the same breed. Leukocyte chemotaxis was over-represented in both hosts, whereas skin degradation and remodeling were only found in TopDEGs from R hosts. Also, these genes indicated the participation of cytokines, such as IL6 and IL22, and the activation of Wingless (WNT)-signaling pathway. A central gene of this pathway, WNT7A, was consistently modulated when hosts were compared. Moreover, the findings based on a genome-wide association study (GWAS) corroborate the prediction of the WNT-signaling pathway as a candidate mechanism of resistance. The regulation of immune response was the most relevant pathway predicted for S hosts. Members of Ap1 and NF-kB families were the most relevant TFs predicted for R and S, respectively.ConclusionThis work provides indications of genetic mechanisms presented by Braford cattle with different levels of resistance in response to tick infestation, contributing to the search of candidate genes for tick resistance in bovine.

ABSTRACT. Filamentous fungi from the genus Trichoderma have been widely investigated due to their considerable production of important biotechnological enzymes. Previous studies have demonstrated that the T. harzianum strain IOC-3844 has a high degree of cellulolytic activity. After excluding the native signal peptide, the open reading frame of the T. harzianum endoglucanase III enzyme was cloned in the expression vector pPICZαA, enabling protein secretion to the culture medium. The recombinant plasmid was used to transform Pichia pastoris. Recombinant expression in the selected clone yielded 300 mg pure enzyme per liter of induced medium. The recombinant enzyme proved to be active in a qualitative analysis using Congo red. A quantitative assay, using dinitrosalicylic acid, revealed a high degree of activity at pH 5.5 and around 48°C. This information contributes to our understanding of the cellulolytic repertory of T. harzianum and the determination of a set of enzymes that can be incorporated into mixes for second-generation ethanol production.

The myogenic differentiation 1 gene (MYOD1) has a key role in skeletal muscle differentiation and composition through its regulation of the expression of several muscle-specific genes. We first used a general linear mixed model approach to evaluate the association of MYOD1 expression levels on individual beef tenderness phenotypes. MYOD1mRNA levels measured by quantitative polymerase chain reactions in 136 Nelore steers were significantly associated (P ≤ 0.01) with Warner-Bratzler shear force, measured on the longissimus dorsi muscle after 7 and 14 days of beef aging. Transcript abundance for the muscle regulatory gene MYOD1 was lower in animals with more tender beef. We also performed a co-expression network analysis using whole transcriptome sequence data generated from 30 samples of longissimus muscle tissue to identify genes that are potentially regulated by MYOD1. The effect of MYOD1 gene expression on beef tenderness may emerge from its function as an activator of muscle-specific gene transcription such as for the serum response factor (C-fos serum response element-binding transcription factor) gene (SRF), which determines muscle tissue development, composition, growth and maturation.

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A Doença Hepática Gordurosa Não Alcoólica (DHGNA) tem ganhado proporções alarmantes, afetando de 25 a 30% da população mundial. Sua ocorrência está associada ao excesso de peso, resistência à insulina e síndrome metabólica. Ela é uma doença silenciosa que evolui do acúmulo de gordura no fígado para a hepatite, fibrose, cirrose e carcinoma. A morbimortalidade associada à DHGNA tem aumentado significativamente, junto com o crescimento do excesso de peso na população. Ainda não há um marcador específico para o diagnóstico, e nem um tratamento farmacológico para a doença. Portanto, a prevenção e o tratamento se baseiam na mudança do estilo de vida, com a adoção de hábitos alimentares saudáveis, que devem necessariamente levar à perda de peso, para a melhora do quadro. O objetivo deste trabalho foi pesquisar e sintetizar informações científicas atualizadas acerca da DHGNA. As buscas, com os descritores utilizados, foram direcionadas às influências dietéticas no desenvolvimento, prevenção e tratamento da DHGNA e aos mecanismos bioquímicos e metabólicos envolvidos com a doença. Foram disponibilizadas informações que ajudam a entender a dietética e a bioquímica no da DHGNA, além da importância da doença em termos de saúde pública. Os temas reportados ajudam a ambientar o profissional nutricionista no cenário atual da educação alimentar e nutricional, voltadas para a prevenção e tratamento da doença.