Molecular biomarkers correspond to all endogenous or exogenous biomolecules, whose presence or alteration in metabolic pathways indicate the response of a biological system to a disturbance caused by internal or external factors. The search for biomarkers has allowed deepening the knowledge of complex pathophysiological mechanisms of diseases, interactions with potential drugs, and the improvement of diagnostic and therapeutic tests, establishing itself as a central point in personalized medicine. In addition, the development of the omics sciences has fostered an increasing exploration in this field of research. This review presents essential and relevant concepts in biomarker research, explores the various definitions and classifications of biomarkers according to their purpose, the critical aspects to be considered in experimental design, the primary employed study models (in vivo, in vitro, and in silico) and the factors that have hindered their ultimate implementation. Finally, important, and current clinical and pharmacological research areas in which biomarker research play a central role are presented.

The aim of the present work was to evaluate molar ratio iron:zinc and the levels of folic acid in biscuit and snacks commercialized in Brazil, prepared with folic acid and iron fortified flours. These nutrients are important for human nutrition; however, iron can have a negative effect on zinc absorption. Molar ratio iron:zinc can indicate if there will be any problems for absorption of these nutrients. The folic acid content varied from 58 to 433 μg/100g and iron and zinc levels varied from 2.9 to 9.4 mg/100g and from 0.2 to 1.3 mg/100g, respectively, for 75 analyzed samples. The average iron contents observed in the products and molar ratio iron:zinc (in average 8:1 for biscuits and 12.8:1 for snacks) could result in problems with the zinc absorption. Moreover, principal component analyses (PCA) indicated low uniformity in the distribution of minerals and vitamin in the majority of the samples, mainly among brands. The results indicated that for the majority of the samples tested folic acid and iron content was higher than expected for flours and could be useful to governmental authorities in their evaluation program of flour fortification.

O objetivo do presente trabalho foi avaliar razão molar ferro: zinco e os níveis de ácido fólico em biscoitos e snacks, comercializados no Brasil, preparados com farinhas fortificadas com ácido fólico e ferro. Esses nutrientes são importantes para nutrição humana, porém, o ferro pode ter efeito negativo na absorção do zinco. A razão molar ferro:zinco pode indicar se haverá problemas para absorção desses nutrientes. O teor de ácido fólico variou de 58 a 433 μg/100g e os níveis de ferro e zinco oscilaram de 2.9 a 9.4 mg/100g e de 0.2 a 1.3 mg/100g, respectivamente, para 75 amostras analisadas. O valor médio observado para o teor de ferro nos produtos e a razão molar ferro:zinco (em média 8:1 para biscoitos e 12,8:1 para snacks) podem resultar em problemas na absorção do zinco. Além disso, a análise por componentes principais (PCA) indicou baixa uniformidade na distribuição dos minerais e da vitamina na maioria das amostras, principalmente entre marcas. Os resultados mostraram que para muitas amostras o teor de ácido fólico e de ferro estava acima do esperado para as farinhas e podem ser utilizados pelas autoridades governamentais para a avaliação do programa de fortificação de farinhas.

During ripening many important physic-chemical changes contribute to fruit quality, and they are precisely determined by gene expression. Specific genes are essential to normal ripening; however, information on gene expression about the majority of tropical fruit, such as bananas and mangoes is limited. In this way, the present study was undertaken with the objective to provide preliminary access to the changes in expression of some genes potentially relevant to banana and mango ripening. To simultaneously evaluate the changes in gene expression, a small collection of genes related to ethylene biosynthesis, starch mobilization, cell wall disassembly, pigment synthesis and ascorbate metabolism was assembled in nylon membranes and probed with cDNA from unripe and ripe fruit. Some interesting differences were observed between gene expression in bananas and mangoes. In relation to starch metabolism, banana a-amylase was induced during ripening while phosphorylase was more induced in mangoes. Similarly, expression of cell wall-related genes for polygalacturonase and expansin were also different in those fruits. Fructanfructosyltransferase, chalcone synthase, and ascorbate oxidase genes were also induced in ripening mangoes, but not in bananas. Although the number of sequences involved was relatively small, this simple and feasible approach provided interesting preliminary data that can be starting points for more in depth studies.