Domains two and three of Escherichia coli ribosomal S1 protein confers 30S subunits a high affinity for downstream A/U-rich mRNAs.

S1, a multi-domain ribosomal protein associated with the 30S subunit, is essential for translation initiation. S1 binds with high affinity to single-stranded mRNA containing A/U-rich patches upstream of the start codon. It was previously reported that domains 1-3 of S1 protein play a role in the docking and unfolding of structured mRNAs to the ribosome. Moreover, S1-deficient 30S subunits are still able to bind to low structured mRNAs. However, mRNAs containing A/U-rich patches in the early base positions after start codon enhance protein synthesis and mRNA binding to the ribosome, which suggests that S1 is also able to interact with these A/U-rich regions. To evaluate the essentiality of S1 domains in the binding to low structured mRNAs containing A/U/G nucleotides after the start codon as well as their role in translation and cell viability, S1 protein deletion variants were generated. We show that S1 domain 3 is necessary to discriminate these mRNAs according to the nucleotide nature since its absence abrogated S1 binding to A/U-rich mRNAs and allowed binding to G-rich mRNAs. Interestingly, domains 2 and 3 were required for the binding of mRNAs containing A/U-rich sequences after the start codon to 30S, in vitro translation and cell viability.

Trichinella spiralis muscle larvae excretory-secretory products induce changes in cytoskeletal and myogenic transcription factors in primary myoblast cultures.

Trichinella spiralis infection in skeletal muscle culminates with nurse cell formation. The participation of excretory-secretory products of the muscle larvae has been implicated in this process through different studies performed in infected muscle and the muscle cell line C2C12. In this work, we developed primary myoblast cultures to analyse the changes induced by excretory-secretory products of the muscle larvae in muscle cells. Microarray analyses revealed expression changes in muscle cell differentiation, proliferation, cytoskeleton organisation, cell motion, transcription, cell cycle, apoptosis and signalling pathways such as MAPK, Jak-STAT, Wnt and PI3K-Akt. Some of these changes were further evaluated by other methodologies such as quantitative real-time PCR (qRT-PCR) and western blot, confirming that excretory-secretory products of the muscle larvae treated primary mouse myoblasts undergo increased proliferation, decreased expression of MHC and up-regulation of α-actin. In addition, changes in relevant muscle transcription factors (Pax7, Myf5 and Mef2c) were observed. Taken together, these results provide new information about how T. spiralis could alter the normal process of skeletal muscle repair after ML invasion to accomplish nurse cell formation.

[Hypertriglyceridemia and low HDL cholesterol as high impact factors for metabolic syndrome diagnosis in apparently healthy adults]. / Hipertrigliceridemia e hipoalfalipoproteinemia. Su impacto para diagnosticar síndrome metabólico.

OBJECTIVE: to determine the impact of lipid serum abnormalities and the prevalence of metabolic syndrome (MS) in healthy adults. METHODS: a cross-sectional, prospective and observational study in apparently healthy adults aged 20 to 60 years who had at least three of the following criteria: abdominal obesity (waist circumference > 102 cm in men and > 88 cm in women), triglycerides ≥ 150 mg/dL, HDL cholesterol < 40 mg/dL in men and < 50 mg/dL in women, blood pressure ≥ 130/85 mmHg and fasting glucose ≥ 110 mg/dL). RESULTS: the prevalence of MS was 20 %, being higher in women (67.7 %) than men (32.3 %). However, no dependence was found with gender (χ(2)= 2.059, p = 0.151). The age range with a higher prevalence of was 45-49 years. Low HDL cholesterol [HR = 11,059 (3.559, 34.610) p < 0.01], was present in 67.9 % of women and hypertriglyceridemia [HR = 15.53 (4.975, 48.513) p < 0.01] was present in 60.5 % of men. CONCLUSIONS: the results suggested that hypertriglyceridemia and hypoalphalipoproteinemia are high impact factors for MS in adults.