Metalloproteomic approach to liver tissue of rats exposed to mercury.

The aims of this study were to identify mercury-associated protein spots in the liver tissue of rats exposed to low concentrations of mercury and to elucidate the physiological and functional aspects of the proteins identified in the protein spots. Therefore, proteomic analysis of the liver tissue of Wistar rats exposed to mercury chloride (4.60 µg kg-1 in Hg2+) was performed for thirty days (Hg-30 group) and sixty days (Hg-60 group). The proteomic profile of the liver tissue of the rats was obtained by two-dimensional electrophoresis (2D-PAGE), and the determinations of total mercury in the liver tissue, pellets and protein spots were performed by graphite furnace atomic absorption spectrometry (GFAAS). ImageMaster 2D Platinum 7.0 software was used to identify the differentially expressed mercury-associated protein spots, which were then characterized by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The determinations by GFAAS indicated a total mercury bioaccumulation of 2812% in the Hg-30 group and 3298% in the Hg-60 group and 10 mercury-associated protein spots with a concentration range of 51 ± 1.0 to 412 ± 6.00 mg kg-1 in the 2D PAGE gels from the liver tissue of the Hg-60 group. The LC-MS/MS analyses allowed the identification of 11 metal binding proteins in mercury-associated protein spots that presented fold change with upregulation >1.5, downregulation < -1.7 or that were expressed only in the Hg-60 group. Using the FASTA sequences of the proteins identified in the mercury-associated protein spots, bioinformatics analyses were performed to elucidate the physiological and functional aspects of the metal binding proteins, allowing us to infer that enzymes such as GSTM2 presented greater mercury concentrations and downregulation < -3; Acaa2 and Bhmt, which showed expression only in the Hg-60 group, among others, may act as potential mercury exposure biomarkers.

Mercury metalloproteomic profile in muscle tissue of Arapaima gigas from the Brazilian Amazon.

Metalloproteomics is an innovative methodology for identifying of protein-associated mercury. Thus, we analyzed the muscle proteome of Arapaima gigas (pirarucu), collected in the Madeira River of the Brazilian Amazon, to identify protein-associated mercury, with the aim of identifying possible mercury biomarkers in fish muscle tissue. After obtaining the protein pellet, we conducted two-dimensional electrophoresis (2D PAGE) to fractionate the muscle proteome. Total mercury in muscle tissue and protein pellets and mapping of mercury content in protein spots of the 2D PAGE gels was determined using graphite furnace atomic absorption spectrometry (GFAAS). The protein-associated mercury identification was performed using liquid chromatography coupled with sequence mass spectrometry (LC‒MS/MS). Total mercury determinations by GFAAS indicated concentrations on the order of 153 ± 1.90 mg kg-1 and 142 ± 1.50 mg kg-1 (total precipitation of protein fraction) and 139 ± 1.45 mg kg-1 (fractional precipitation of protein fraction) in muscle tissue and protein pellets, respectively. Mercury concentrations in the range of 48 ± 0.90 to 165 ± 3.00 mg kg-1 were found in twelve protein spots. Among the 2D PAGE protein spots, eleven Hg-binding proteins were identified using LC‒MS/MS, which showed characteristics of mercury exposure biomarkers for important metabolic functions, such as five parvalbumin isoforms, triosephosphate isomerase, cofilin 2 (muscle), and fructose-bisphosphate aldolases.

Effects of zinc supplementation on 1- to 5-year old children.

OBJECTIVE: To assess the impact of zinc supplementation on nutritional and biochemical parameters among children aged 12 to 59 months. METHODS: A blinded randomized clinical trial was carried out with 58 children aged 12 to 59 months included in the Programa Governamental de Combate a Carências Nutricionais (National Child Nutritional Program), which provided them with 2 kg of iron-fortified milk. The supplementation group (n = 28) received 10 mg/day of zinc sulfate for four months, and the control group (n = 30) received placebo. The following parameters were used to assess the nutritional status: weight-for-height and height-for-age expressed as z scores, according to National Center for Health Statistics (NCHS) standards, biochemical measurements of serum iron and serum zinc, and hemoglobin and hematocrit levels. RESULTS: Zinc supplementation did not have a remarkable influence on anthropometric parameters. Baseline serum zinc levels were low in both groups. After supplementation, variations in mean hemoglobin (p = 0.002), hematocrit (p = 0.001), serum zinc (p = 0.023), and serum iron (p = 0.013) levels significantly increased in the zinc supplementation group. CONCLUSION: Zinc supplementation improved hemoglobin response and normalized serum zinc concentration. The results show the importance of establishing policies for nutritional care that can tackle zinc deficiency as well.

Efeito da suplementação de zinco a crianças de 1 a 5 anos de idade / Effects of zinc supplementation on 1- to 5-year old children

OBJETIVO: Avaliar o impacto da suplementação com zinco sobre os parâmetros nutricionais e bioquímicos entre crianças de 12 a 59 meses de idade. MÉTODOS: Foi realizado um estudo clínico randomizado unicego com 58 crianças entre 12 e 59 meses participantes do Programa Governamental de Combate a Carências Nutricionais, que fornecia mensalmente 2 kg de leite fortificado com ferro. O grupo intervenção (n = 28) foi suplementado com 10 mg/dia de sulfato de zinco por 4 meses, e o grupo controle (n = 30) recebeu solução placebo. Para avaliação do estado nutricional, utilizaram-se os indicadores peso por estatura e estatura por idade, expressos em escores z, do padrão de referência NCHS (National Center for Health Statistics), parâmetros bioquímicos de ferro e zinco séricos e concentração de hemoglobina e hematócrito. RESULTADOS: A suplementação com zinco não interferiu significativamente sobre as condições antropométricas das crianças. Ambos os grupos apresentavam concentrações iniciais baixas de zinco sérico. Após o término do período de intervenção, a variação nos níveis médios de hemoglobina (p = 0,002) e as concentrações de hematócrito (p = 0,001), zinco (p = 0,023) e ferro séricos (p = 0,013) foram significativamente mais elevadas no grupo suplementado. CONCLUSÃO: A suplementação com zinco promoveu melhora na resposta hemoglobínica e normalizou a concentração sérica de zinco. Os resultados mostram a importância de se estabelecer políticas de combate a carências nutricionais que também possam dar atenção à carência de zinco.