Carlos Gustavo Nunes-Silva

Guarana (Paullinia cupana var. sorbilis), an anciently consumed stimulant from the Amazon rain forest: the seeded-fruit transcriptome

Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.

Diploid Male Production of Two Amazonian Melipona Bees (Hymenoptera: Apidae)

The diploid male has already been recorded for Melipona Illger, and herein, in Melipona seminigra merrillae Cockerell and Melipona interrupta manaosensis Schwarz. This paper was carried out at the Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, AM, Brazil. We produced and monitored 31 new colonies of M. s. merrillae and 32 new colonies of M. i. manaosensis. We sampled 2,995 pupae of M. s. merrillae and 2,020 of M. i. manaosensis. In colonies with a 1 : 1 sex ratio, male diploidy was confirmed by cytogenetic analysis and workers’ behavior. We estimated 16 sex-determining alleles in M. s. merrillae and 22 in M. i. manaosensis. In colonies of M. i. manaosensis in a 1 : 1 sex ratio, workers killed the males and the queen that produced them soon after they emerged, as predicted. This behavior was not registered for M. s. merrillae, and sex ratios did not stay 1 : 1, indicating polyandry for this species.

Cytogenetic analysis of the Amazon stingless bee Melipona seminigra merrillae reveals different chromosome number for the genus

Cytogenetic analysis of the Amazon stingless bee Melipona seminigra merrillae, by conventional Giemsa staining and C-banding, revealed a different chromosome number for Melipona: 2n = 22 for females and diploid drones while the haploid drones present n = 11. There is no evidence of B chromosomes. This result contrasts with previous studies, in which the chromosome number of 19 Melipona species was determined as 2n = 18 for females and n = 9 for haploid males. Based on cytogenetic information available for other Melipona species, we propose that M. s. merrillae has a more derived diploid number. This indicates that chromosome number is not a conservative characteristic within the genus as previously thought. Cytogenetic data for stingless bees are scarce, especially in Amazon region. Additional studies will be very important in order to promote Melipona karyoevolution discussion and consequently a taxonomy review.

Pollen diversity and pollen ingestion in an Amazonian stingless bee, Melipona seminigra (Hymenoptera, Apidae)

Summary The knowledge of digestive processes correlated with the species of plant used by stingless bees is important for development of Meliponiculture, or stingless bee keeping, which is a lucrative activity in the Brazilian Amazon. The number and state of digestion of pollen grains in the midgut and rectum, as well as the pollinic diversity and activity of some digestive enzymes, were analyzed in different life stages of the stingless bee Melipona seminigra to compare the difference of digestion process in larvae, adult workers (nurse and forager) and virgin queens of Amazon stingless bees. Pollen consumption was found to be similar for nurse workers and virgin queens, while larvae consume significantly more pollen than other stages. A survey of pollinic diversity identified eight plant families, with the majority of digested pollen collected from the Melastomataceae (97.85%), and most undigested pollen from the Fabaceae (51%). The activity of hydrolytic enzymes was analyzed in larval food, pollen stored in the colony, and the midguts of bees at different life stages, whose comparisons revealed differences between each stage and caste.

Antimicrobial activity of honeys from two stingless honeybee species and Apis mellifera (Hymenoptera: Apidae) against pathogenic microorganisms

Honeys are described possessing different properties including antimicrobial. Many studies have presented this activity of honeys produced by Apis mellifera bees, however studies including activities of stingless bees honeys are scarce. The aim of this study was to compare the antimicrobial activity of honeys collected in the Amazonas State from Melipona compressipes, Melipona seminigra and Apis mellifera against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Chromobacterium violaceum, and Candida albicans. Minimum inhibitory concentrations were determined using the agar dilution method with Muller-Hinton agar (for bacteria) or Saboraud agar (for yeast). Staphylococcus aureus and E. faecalis were inhibited by all honeys at concentrations below 12%, while E. coli and C. violaceum were inhibited by stingless bee honeys at concentrations between 10 and 20%. A. mellifera honey inhibited E. coli at a concentration of 7% and Candida violaceum at 0.7%. C. albicans were inhibited only with honey concentrations between 30 and 40%. All examined honey had antimicrobial activity against the tested pathogens, thus serving as potential antimicrobial agents for several therapeutic approaches.

Endo and exoglucanases produced by Penicillium citrinum isolated from Amazon

Background Cellulolytic enzymes (glucohidrolases EC 3.2.1.-) are biocatalizators highly specific. They act in synergy to hydrolyze b-1,4 bonds between monosaccharide units of D-glucose in the cellulose chain releasing its constituents. Cellulases are categorized according to the place they act in the cellulosic fiber. Endoglucanases start hydrolysis, exoglucanases act in the reduced terminal produced by endoglucanases followed by b-glycosidase which act in the product of exoglucanases catalysis releasing glucose monomers. Fungi are considered the best cellulolytic enzyme producers due to its natural cellulases that complete saccharification of lignocellulose. Species of Penicillium have been reported as excellent producers of cellulolytic enzymes when compared to commercial species and strains [1]. Aiming to contribute to biocatalytic processes and obtention of new sources for cellulolytic enzyme, this work has as objective the production of endoglucanases and exoglucanases from Penicillium citrinum isolated from an agro industrial residue in Amazon.

Purification of endoglucanase produced by Penicillium citrinum isolated from Amazon

Background The cellulolytic enzyme complex has many important biotechnological applications such as beverage, textile, food, paper and cellulose industries, as well as in degradation of lignocellulosic for ethanol biofuel production [1]. According to the enzymatic activity, cellulolytic complex is subdivided in three classes: endoglucanases, exoglucanases and b-D-glycosidases. Endoglucanases (endo-b-1,4-glucanase, EC 3.2.1.4) are responsible to initiate cleavage, hydrolyzing randomly internal regions from the amorphous cellulose fiber structures, releasing oligosaccharides from different grades of polymerization. These will be hydrolyzed by exoglucanases releasing cellobiose followed by b-D-glycosidades being hydrolyzed to glucose [1]. Penicillium citrinum has worldwide occurrence. Commonly in the soil, this specie is described as good xylanase and cellulase producer [2,3]. This work describes liquid chromatography to separate endoglucanases of Penicillium citrinum supernatant from submerse fermentation process.