Instar Drosophila Larvae Research Articles

Purification of aspartate transcarbamylase from Drosophila melanogaster.

A purification procedure is described by which aspartate transcarbamylase was obtained from cultured cells of Drosophila melanogaster as part of a high-molecular-weight enzyme complex. The complex is shown to contain several polypeptides. An antiserum directed against the complex enzyme inhibited in vitro the activity of aspartate transcarbamylase, carbamylphosphate synthetase and dihydro-orotase which were shown to copurify on a sucrose gradient and by gel electrophoresis. A fast preparation procedure using this antiserum yielded a 220 000-molecular-weight protein in addition to the polypeptides present in the complex. A purification procedure is also described to obtain aspartate transcarbamylase from second instar larvae of Drosophila. At this stage, the enzyme is not complexed with carbamylphosphate synthetase and dihydro-orotase but exhibits the same molecular weight as the aspartate transcarbamylase moiety found in the high-molecular-weight complex of cultured cells.

RNA and protein synthesis inDrosophila leg discs cultured in vitro

Imaginal leg discs from late third instarDrosophila larvae were cultured in Mandaron's medium without hormone or with α-ecdysone or β-ecdysone. Incorporation of labelled precursors (tritiated uridine, tritiated leucine or tritiated proline) was studied as a function of the stage of in vitro disc development.In the absence of moulting hormone, uridine incorporation decreased as soon as the discs were explanted; leucine and proline incorporation however began to decrease only after 6 to 12 h.α- and β-ecdysone stimulated the incorporation of all three precursors; however the rate of the incorporation varied as a function of the morphological disc development.The maxima and minima of uridine incorporation preceeded in time those of proline and leucine incorporation.The peaks of incorporation were coincident with salient morphological events of development: evagination, secretion of pupal and imaginal cuticles.There were no significant differences in uridine incorporation in the presence of α-ecdysone or β-ecdysone. Leucine and proline incorporation maxima however were significantly higher in the presence of α-ecdysone than of β-ecdysone.The results show that α-ecdysone-and to a lesser extent also β-ecdysone-can induce the macromolecular syntheses required for the development of the appendage in vitro.

Parameters influencing the acquisition of competence for metamorphosis in imaginal disks of Drosophila

When imaginal disks from first and early second instar larvae of Drosophila are transplanted into larval hosts that are ready to pupate, they are unable to differentiate adult structures. The disks gradually become competent to respond with imaginal differentiation towards the end of the second larval instar (Fig. 1). The first sign of imaginal differentiation is a light-orange pigment that appears in the presumptive eye region when eye-antennal disks from early second instar larvae were subjected to immediate metamorphosis. This pigment was identified as being composed of ommochromes and drosopterins. Incompetent eye-antennal disks from early second instar donors were cultured in adult females for 2 to 5 days, and then retransplanted into late third instar larval hosts. If the adult host flies were kept on standard food the disks grew by cell multiplication (Fig. 2c) and became competent to undergo imaginal differentiation (Fig. 3). If, on the other hand, the adult hosts were starved on a protein-free sugar diet, cell divisions were effectively blocked in the disks. These did not noticeably grow (Fig. 2b) and remained incompetent (Fig. 3). The block caused by starvation proved to be reversible. Based on these results the hypothesis is advanced that the acquisition of competence requires a minimum number of cell divisions to take place in the disk primordium.

The isolation of intracellular antibacterial activity from Drosophila melanogaster larvae

A lysosomal fraction of late third instar Drosophila melanogaster larvae was obtained by differential centrifugation of whole larvae homogenates. Acid-ethanol extraction was employed to isolate trypsin sensitive antibacterial activity from the lysosomal fraction. Attempts to detect lysozyme activity in freeze-dried samples of the antibacterial extract were unsuccessful.

Effect of nitrogen mustard on the development of the bristle organ and on the rate of transdetermination ofDrosophila melanogaster

1. Injection of nitrogen mustard (HN-3) into late third instar larvae ofDrosophila melanogaster and treatment of male foreleg disks with HN-3in vitro results in the following: formation of fewer bristles and hairs, reduction in size of leg parts, alteration of normal bristle patterns, and differentiation of bristle organs without sockets and bracts. 2. When disks, treated with HN-3, were cultivated in adult hosts for 14 days before transplantation into metamorphosing larvae, mostly complete bristle organs were formed, whereby bristles of distal leg parts usually form bracts. 3. Transdetermination is completely suppressed after HN-3-treatment, although proliferation occurs in disks treated with a concentration of 0,02 Μl HN-3 per ml Insect-Ringer. 4. Injection of HN-3 into late third instar larvae results in the induction of somatic mutations. 5. The effect of nitrogen mustard is compared with the effect of mitomycin C treatment and discussed with respect of the suppression of transdetermination.

Influencing of bristle differentiation and pattern formation by mitomycin in Drosophila melanogaster

Injection of mitomycin C into late third instar larvae ofDrosophila leads during metamorphosis to the differentiation of bristles without sockets and bracts, and to altered bristle patterns in structures of the integument.

Puff induction in larval salivary gland chromosomes of Drosophila hydei sturtevant.

The puffing pattern in salivary chromosomes of third instar larvae ofDrosophila hydei was studied following treatment with various gases, potassium cyanide, or vacuum. It was found that a number of specific puffs appear when anaerobiosis is followed by exposure to air or oxygen. These puffs seem to be independent of larval age, and are identical with some of those puffs which can be induced by raised temperature. It is suggested that the chromosomal loci involved, are connected with respiration.

Tyrosine- O-phosphate in Drosophila

By means of an analytical method based on high voltage electrophoresis, and by isolation, synthesis, and characterization, it has been shown that tyrosine- O-phosphate is a normal and prominent constituent of third instar larvae of Drosophila. The compound accumulates during the rapid growth period following the second molt and disappears abruptly at puparium formation.

THE GENETIC BASIS OF SOMATIC DAMAGE PRODUCED BY RADIATION IN THIRD INSTAR LARVAE OF DROSOPHILA MELANOGASTER. I. DEATH BEFORE MATURITY.

Third-instar larvae of different genotypes were exposed to X-radiation of various doses, and survival was scored separately for the sexes and genotypes. Most of the observed correlations agree with the hypothesis that somatic radiation damage was exclusively or almost exclusively due to chromosome breakage followed by chromosome loss, cellular damage or death resulting whenever a portion of the genome was no longer represented in at least haploid condition. Monosomaty for either of the long autosomes does not appear to be detrimental to somatic cells. The detailed evidence has been summarized at the beginning of the discussion.

Increased recombination from female Drosophila irradiated as larvae without oocytes.

Different x-ray doses to late third instar larvae of Drosophila produced elevated frequencies of crossovers only from eggs laid in the first week of the imagoes. Three broods from 8 to 21 day-old adults were homogeneous anaong control and three irradiation dosage groups. Comparison of noncrossover and crossover frequencies showed no evidence of radioresistant cells among the oogonia present in x-rayed larvae. Higher crossover and lower noncrossover values were found in the 14 to 21 day brood rather than in the earliest brood of the controls. This response of Drosophila and the lack of such response of Habrobracon to irradiation are discussed. (auth)

Regulation and Differentiation within Field-districts in Imaginal Discs of Drosophila

ABSTRACT Genital imaginal discs of third instar larvae of Drosophila have been cut into medial, paramedial, or transverse parts of different sizes. The fragments were then implanted into the body cavity of a host larva. This medium provides the implants with ample nutritional material and hormones. The fragments thus differentiate their imaginal structures simultaneously with the metamorphosing host. A detailed analysis of the respective differentiations of the various parts has led to the following results and revealed the following properties of the different blastemata which are embodied in a genital disc (Hadorn et al., 1946, 1949,1950).