On the apterous line of the termite Velocitermes heteropterus (Isoptera: Termitidae): developmental pathways and cellulose digestion.

Termites are social insects with an extraordinary ability to digest cellulose. Termite societies are structured into castes, and patterns of postembryonic development vary between different termite species. The apterous line may exhibit polymorphism ("physical castes"), in which workers are dimorphic and soldiers can be either dimorphic or trimorphic. We examined the occurrence of polymorphism in the apterous line of Velocitermes heteropterus and determined the developmental pathways for this termite species. We also investigated the expression of the cellulase genes encoding ß-glucosidase and endo-ß-1,4-glucanase among the castes to determine whether there is a difference in digestion and, consequently, a possible division of labor with respect to this activity among the worker castes. The apterous line of V. heteropterus presents individuals of both sexes with two larval instars. The female larvae become major workers, and the male larvae become minor workers and soldiers. The expression of ß-glucosidase was similar within the castes, but the expression of endo-ß-1,4-glucanase was higher in workers than in soldiers. No significant differences were found between minor and major workers. These results suggest that there is no division of labor between the minors and majors with regard to cellulose digestion, with both workers contributing similarly to this process.

Human herpesvirus 6 in oral fluids from healthy individuals.

BACKGROUND: Human herpesvirus 6 (HHV6) is the etiologic agent of exanthem subitum. The virus is latent in salivary glands and saliva is the main form of viral transmission. The objective of this study was to assess HHV6 incidence in the fluids from healthy individuals using a standardised technique for collecting and extracting viral DNA from gingival crevicular fluid, whole saliva and parotid gland saliva. DESIGN: Samples of oral fluids and peripheral blood were collected from 28 blood donors and HHV6 was detected using PCR assay. Parotid gland saliva and gingival crevicular fluid were collected by endodontic paper cones in order to not contaminate these fluids with whole saliva. RESULTS: Of the 28 donors, 20 (71.4%) presented positive results in at least one of the three oral fluids researched. Whole saliva was positive in 19 (67.8%) volunteers, while only four (14.2%) samples of gingival crevicular fluid and four of parotid gland saliva proved to be positive. CONCLUSIONS: The results suggest that HHV6 is present in the saliva of a large proportion of the healthy adult population. The use of endodontic paper cones for oral fluid collection and viral extraction was efficient, simple, cheap and painless. In spite of, the small number of cases studied it was possible to demonstrate that neither gingival crevicular fluid nor parotid gland saliva were the principal source of HHV6 in whole saliva.