Development of DNA puffs and patterns of polypeptide synthesis in the salivary glands of Bradysia hygida

Abstract

In the three salivary gland regions of Bradysia hygida (Diptera, Sciaridae) the patterns of polypeptide synthesis, as revealed by electrophoresis and fluorography, are very stable during the fourth larval instar until about 30 h before the pupal molt. At this age the patterns of polypeptide synthesis start to undergo marked changes. The striking correlations between these changes and the development of two distinct groups of DNA puffs support the proposal that DNA puffs are causally related to the synthesis of specific proteins in the salivary glands.

Bradysia hygida (Diptera, Sciaridae) presents two eukaryotic Elongation Factor 1A gene homologues: partial characterization of the eukaryotic Elongation Factor 1A-F1 gene

“…These studies led to the suggestion that the biological role of gene amplification is to provide large amounts of salivary gland proteins that are employed in the construction of the cocoon in which the larvae pupate (5)(6)(7)(8). This suggestion was confirmed by the demonstration that polyclonal antibodies raised against either the product of DNA puff B10…”

“…The expansion and regression of specific DNA puffs can be related to the developmentally regulated synthesis of groups of salivary gland polypeptides (5)(6)(7)(8). These studies led to the suggestion that the biological role of gene amplification is to provide large amounts of salivary gland proteins that are employed in the construction of the cocoon in which the larvae pupate (5)(6)(7)(8).…”

Genome size of three Brazilian flies from the Sciaridae family

“…The sciarid Bradysia hygida (Sauaia and Alves, 1968) has been reared since 1995 at the Departamento de Biologia Celular e Genética at the Universidade Estadual de Maringá, Paraná, Brazil, according to the conditions described by Laicine et al (1984) and da Conceição Silva and Fernandez (2000). At 20°C B. hygida has a 36-day life cycle.…”

“…At 20°C B. hygida has a 36-day life cycle. During the larval stage of which three molts occur delimiting four instars, the larval eyespots appearing at the sixth day of the fourth instar and are a useful marker to determine larval age and establish the different developmental stages on this instar (Laicine et al, 1984). In our investigation we used E5 aged female larvae.…”

“…Because this species only survives for three generations under laboratory conditions we collected R. americana larvae in the field and maintained them at 20°C for one generation using the same diet as for B. hygida (Laicine et al, 1984;da Conceição Silva and Fernandez, 2000). For our study we sacrificed the R. americana larvae during the 3A period (Yokosawa et al, 1999) just before the onset of DNA amplification which in this species occurs during the fourth instar.…”