RESUMO
Xylanases are hemicellulases that break down xylan to soluble pentoses. They are used for industrial purposes, such as paper whitening, beverage clarification, and biofuel production. The second-generation bioethanol production is hindered by the enzymatic hydrolysis step of the lignocellulosic biomass, due to the complex arrangement established among its constituents. Xylanases can potentially increase the production yield by improving the action of the cellulolytic enzyme complex. We prospected endo-ß-1,4-xylanases from meta-transcriptomes of the termite Heterotermes tenuis. In silico structural characterization and functional analysis of an endo-ß-1,4-xylanase from a symbiotic protist of H. tenuis indicate two active sites and a substrate-binding groove needed for the catalytic activity. No N-glycosylation sites were found. This endo-ß-1,4-xylanase was recombinantly expressed in Pichia pastoris and Escherichia coli cells, presenting a molecular mass of approximately 20 kDa. Enzymatic activity assay using recombinant endo-ß-1,4-xylanase was also performed on 1% xylan agar stained with Congo red at 30 °C and 40 °C. The enzyme expressed in both systems was able to hydrolyze the substrate xylan, becoming a promising candidate for further analysis aiming to determine its potential for application in industrial xylan degradation processes.
RESUMO
Giardia comprises one genus with several morphologically distinct species described in mammals (including humans, marsupials, rodents), birds, and amphibians. This group of protists provokes diarrhoea diseases in humans and animals worldwide. Transmission of the parasite occurs through the faecal-oral route. Regarding the presence of Giardia in invertebrates, some works have shown that flies can transmit Giardia cysts by contact and transport between contaminated faeces and food. In this way, flies would eventually transmit this parasite. To date, Giardia's presence in the gut of other invertebrates has not been described in the literature. Here we show by first time, using scanning electron microscopy, the presence of Giardia-like trophozoites in the gut of termite Heterotermes tenuis. Two groups of Giardia were found based exclusively on the size and the flange shape of the protozoa: one presented eight flagella, a ventral disc, size, and shape very similar to Giardia intestinalis. In contrast, other cells were smaller and showed some differences in the external morphology. We cannot exclude the possibility that they correspond to the same species and that these differences result from protozoan heterogeneity.
Assuntos
Giardia/isolamento & purificação , Giardíase/parasitologia , Isópteros/parasitologia , Animais , Brasil , Fezes/parasitologia , Flagelos/ultraestrutura , Giardia/classificação , Giardia/ultraestrutura , Giardíase/transmissão , Microscopia Eletrônica de Varredura , Organelas/ultraestrutura , Trofozoítos/citologiaRESUMO
The area of foraging of the termite species Heterotermes tenuis was evaluated using the Termitrap® bait marked with the radioisotope 32P. The experiment was conducted in an area with sugarcane, in Piracicaba,SP Brazil. Twenty infestion foci of H. tenuis were identified with baits. Each focus recieved baits labeled with 18.5 MBb (500 mCi) 32P in the form of sodium phosphate diluted in 15 ml of distilled water. Surrounding the marked baits were installed baits without marker in four points: North, South, East and West, halfway of 1, 5, 10 and 20 meters. Each treatment was represented previously by a focus settled and marked and one of the distances specified for the monitoring bait, being repeated of 4 to 6 times. After 15 days of the demarcation, the evaluation was proceeded by collecting 15 individuals of H. tenuis from each infested monitoring bait. These insects were transferred to glass flasks with distilled water, and analyzed in a liquid cintilador, by the test of Cerenkov. It was verified that in only 20% of the monitoring baits termites were collected and 11.3% were marked with the radioisotope, and that several colonies may by foraging in a same area. The foraging area for a colony of H. tenuis in sugarcane can vary from 3 to 1,250 m2.
Estudou-se a área de forrageamento do cupim Heterotermes tenuis utilizando-se a isca Termitrap® marcada com o radioisótopo 32P. O experimento foi conduzido numa área com cana-de-açúcar, em Piracicaba-SP. Foram localizados 20 focos de H. tenuis, com iscas. Em cada um desses focos aplicou-se uma isca Termitrap® impregnada com 18,5 MBb (500 mCi) 32P na forma de fosfato de sódio diluído em 15 ml de água destilada. Ao redor das iscas marcadas, foram instaladas iscas sem marcador em quatro pontos: Norte, Sul, Leste e Oeste, eqüidistantes de 1, 5, 10 e 20 metros. Cada tratamento foi representado por um foco previamente determinado e marcado e uma das distâncias estipuladas para a isca de monitoramento, sendo repetido de 4 a 6 vezes. Após 15 dias da marcação, procedeu-se a avaliação coletando-se 15 indivíduos de H. tenuis de cada isca de monitoramento infestada, acondicionando-os em frascos de vidro com água destilada, que foram analisados em cintilador líquido, pelo teste de Cerenkov. Verificou-se que em apenas 20% das iscas de monitoramento coletaram-se cupins e 11,3% estavam marcadas com o radioisótopo. Constatou-se que ocorrem diversas colônias forrageando numa mesma área. A área de forrageamento de H. tenuis em cana-de-açúcar pode variar de 3 a 1.250 m2.
RESUMO
The area of foraging of the termite species Heterotermes tenuis was evaluated using the Termitrap® bait marked with the radioisotope 32P. The experiment was conducted in an area with sugarcane, in Piracicaba,SP Brazil. Twenty infestion foci of H. tenuis were identified with baits. Each focus recieved baits labeled with 18.5 MBb (500 mCi) 32P in the form of sodium phosphate diluted in 15 ml of distilled water. Surrounding the marked baits were installed baits without marker in four points: North, South, East and West, halfway of 1, 5, 10 and 20 meters. Each treatment was represented previously by a focus settled and marked and one of the distances specified for the monitoring bait, being repeated of 4 to 6 times. After 15 days of the demarcation, the evaluation was proceeded by collecting 15 individuals of H. tenuis from each infested monitoring bait. These insects were transferred to glass flasks with distilled water, and analyzed in a liquid cintilador, by the test of Cerenkov. It was verified that in only 20% of the monitoring baits termites were collected and 11.3% were marked with the radioisotope, and that several colonies may by foraging in a same area. The foraging area for a colony of H. tenuis in sugarcane can vary from 3 to 1,250 m2.
Estudou-se a área de forrageamento do cupim Heterotermes tenuis utilizando-se a isca Termitrap® marcada com o radioisótopo 32P. O experimento foi conduzido numa área com cana-de-açúcar, em Piracicaba-SP. Foram localizados 20 focos de H. tenuis, com iscas. Em cada um desses focos aplicou-se uma isca Termitrap® impregnada com 18,5 MBb (500 mCi) 32P na forma de fosfato de sódio diluído em 15 ml de água destilada. Ao redor das iscas marcadas, foram instaladas iscas sem marcador em quatro pontos: Norte, Sul, Leste e Oeste, eqüidistantes de 1, 5, 10 e 20 metros. Cada tratamento foi representado por um foco previamente determinado e marcado e uma das distâncias estipuladas para a isca de monitoramento, sendo repetido de 4 a 6 vezes. Após 15 dias da marcação, procedeu-se a avaliação coletando-se 15 indivíduos de H. tenuis de cada isca de monitoramento infestada, acondicionando-os em frascos de vidro com água destilada, que foram analisados em cintilador líquido, pelo teste de Cerenkov. Verificou-se que em apenas 20% das iscas de monitoramento coletaram-se cupins e 11,3% estavam marcadas com o radioisótopo. Constatou-se que ocorrem diversas colônias forrageando numa mesma área. A área de forrageamento de H. tenuis em cana-de-açúcar pode variar de 3 a 1.250 m2.