Relationship between rainfall and temperature: observations on the cases of visceral leishmaniasis in São Luis Island, State of Maranhão, Brazil

INTRODUCTION: Visceral leishmaniasis is a serious public health problem that requires global control strategies, especially with respect to factors that may intervene in reducing the incidence of endemicity. In this work, rainfall density and temperature were correlated with the incidence of human cases in an area endemic for leishmaniasis in São Luis do Maranhão, Northeastern Brazil. METHODS: Notification of human cases by the National Health Foundation/Regional Coordination of Maranhão (FUNASA/COREMA) from 2002 to 2010 was used. Ecological data (mean temperature and rainfall density) were provided by the Meteorological Office of State. RESULTS: A significant association was verified between the number of VL cases and rainfall rate but not in the analysis concerning mean temperatures. CONCLUSIONS: These data suggest that the control actions in visceral leishmaniasis should be performed during rainy season in the State of Maranhão, which is in the first half of the year

Control of carotenoid gene expression in Bixa orellana L. leaves treated with norflurazon

Bixa orellana (annatto or lipstick tree) is a perennial tropical plant that stores and produces considerable quantities of the apocarotenoid bixin, a culturally and economically important pigment used worldwide. However, the mechanisms underlying the gene regulation and pigment accumulation of bixin and carotenoids in annatto remain unknown. Bixin is present in the different tissues of the plant, although this pigment is primarily accumulated in the seed coat. Thus, the leaves are useful organs for understanding carotenoid and bixin production, thereby facilitating the study of this pigment, which would otherwise be difficult in ligneous adult plants. To study the regulation of bixin synthesis and to determine which genes are important regulatory molecules at the transcription level, the herbicide norflurazon (NF) was used to block carotenoid synthesis and bixin concentrations in B. orellana leaves. The genes activated in the early stages of the carotenoid pathway are involved in lycopene production (dxs, psy and pds), and those induced in the later stages of the carotenoid pathway, such as β and ε-lycopene cyclases and boccd1, were differentially expressed compared with the control. The expression of some genes was more susceptible to certain concentrations of NF, potentially reflecting the roles of these genes in carotenoid synthesis in B. orellana. These results suggest that apocarotenoids, such as bixin, are synthesized using alternative precursors through the actions of genes that have not yet been identified