Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings

The transcription factor Snf1p is involved in a Tup1p-independent manner in the glucose regulation of the major methanol metabolism genes of Hansenula polymorpha

Hansenula polymorpha is a methylotrophic yeast widely employed in biotechnology as a ''protein factory''. Most promoters used for heterologous protein expression, like MOX (methanol oxidase) and DAS (di-hydroxy acetone synthase), are involved in the peroxisomal methanol metabolism (C1 metabolism) and are under strong glucose repression. Interestingly, the MOX promoter is subjected to glucose regulation also in Saccharomyces cerevisiae, a non-methylotrophic yeast in which this phenomenon is well studied. In this species, the transcription factor Tup1p plays an essential role in glucose repression of several genes. This effect is counteracted by the activator Snf1p when glucose is exhausted from medium. Therefore, to test whether this regulatory circuit has been conserved in H. polymorpha, HpTUP1 and HpSNF1 were partially cloned and disrupted. Deletion of HpTUP1 did not affect glucose repression of the major C1 metabolism genes (MOX, DAS). Thus, though conserved, HpTUP1 does not seem to take part in a general glucose repression in H. polymorpha. In contrast, the deletion of HpSNF1 led to significant decreases in the activation of these genes in the absence of glucose. Therefore, the effect of HpSNF1 in transcriptional activation may be through an HpTUP1- independent circuit.

Identification of Astyanax altiparanae (Teleostei, Characidae) in the Iguaçu River, Brazil, based on mitochondrial DNA and RAPD markers

Astyanax fishes are among the most important food-web components of South America rivers. In the Iguaçu River basin, the Astyanax genus is represented mainly by endemic species. For millions of years, that hydrographic basin has been geographically isolated from the Paraná River basin by the Iguaçu Falls. Recently, a species from the Upper Paraná River basin identified as Astyanax bimaculatus was revised and described as a new species named Astyanax altiparanae Garutti e Britski, 2000. Fauna endemism and geographic isolation triggered interest in investigations to evaluate the identification and genetic relatedness among two A. altiparanae populations from the Upper Paraná River basin and the population identified as A. bimaculatus in the Iguaçu River, upstream from the Iguaçu Falls. Mitochondrial DNA sequences and RAPD markers revealed high genetic diversity within each population, as well as low genetic distance, high gene flow, and high mitochondrial DNA similarity among all three populations. In conjunction with morphological similarities, these results demonstrated that the population presently known as Astyanax bimaculatus in the Iguaçu River should actually be stated as Astyanax altiparanae. Furthermore, it could be inferred that the A. altiparanae population is not endemic and most likely it was recently introduced in the Iguaçu River basin, maintaining the ancestral genetic identity