Genetic studies of multiple paternity are a valuable tool to gain information on the reproductive biology of turtles. We analyzed paternity type in Podocnemis sextuberculata and related number of fathers per nest to nesting period (beginning, middle, or end of nesting season); clutch size (number of eggs); female size; and hatchling success. Females were captured and maximum linear carapace lengths measured during the 60 days that encompass the nesting season at Rio Trombetas Biological Reserve (Pará, Brazil). Nests were marked and blood samples collected from hatchlings.
The genus Theobroma found in the Amazon region is composed of 22 species, including Theobroma speciosum, better known as cacauí. These species are constantly threatened by forest fragmentation caused by human activities and require conservation strategies and management aimed at preserving them in their natural environments. The main objective of this study was to analyze the population structure and genetic diversity within and between natural populations of T.
Gastric cancer is one of most frequent causes of death in Brazil. The city of Manaus has one of the highest incidences of this disease in Brazil. The Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that is classified as a group 1 carcinogen by the International Agency for Research on Cancer. We obtained biopsies from 6 control subjects and 10 patients with gastric carcinomas living in Manaus. In the patients, the samples were taken from tumors and from adjacent non-cancerous mucosa.
In the State of Acre, the Brazil nut tree, Bertholletia excelsa (Lecythidaceae), is classified by the local population into two types according to morphological characteristics, including color and quality of wood, shape of the trunk and crown, and fruit production. We examined the reliability of this classification by comparing morphological and molecular data of four populations of Brazil nut trees from Vale do Rio Acre in the Brazilian Amazon. For the morphological analysis, we evaluated qualitative and quantitative information of the trees, fruits, and seeds.
Starch gel electrophoresis was used for examining the transferrin gene locus (Tf) and two esterase gene loci (Est-1 and Est-D1) of a pirarucu (Arapaima gigas) population sample collected from Santa Cruz Lake, Tefé River, Amazonas, Brazil. The Tf locus was tentatively classified as being polymorphic, showing two double-banded patterns (Tf 12 and Tf 22) of the three theoretically expected ones (Tf11, Tf 12 and Tf 22), presumably controlled by two co-dominant alleles, Tf 1 and Tf 2.
The large pimelodid, Brachyplatystoma rousseauxii, is one of the two most important catfish species for the fisheries in the Amazon. It is captured by commercial and artisanal fishing fleets in at least five Amazonian countries, at fishing grounds more than 5000 km apart. Current evidence suggests a complex life cycle that includes the longest reproductive migration known for a freshwater fish species. Experimental fisheries have pointed to a decrease in yield in the Western Amazon.