The lifespan of starving flies of different Drosophila melanogaster stocks: effects of caffeine and He-Ne laser light

Aim. Analysis of the chronic effects of caffeine and laser radiation on starvation resistance in Drosophila melanogaster, in depends on the genotype. Methods. The experiments were carried out in wild type stocks of Drosophila melanogaster: Canton-S and Oregon; mutant stock ebony and stocks with mutation ebony saturated by stocks Canton-S and Oregon – ebonyC-S and ebonyOr. Caffeine was applied in concentration of 0.5 mg/ml in the cultural medium. Flies were exposed to He-Ne laser light of wavelength 632.8 nm and surface power density 0.03 mW/cm2 for 5 minutes. Control flies were grown under standard living conditions. Results. The lifespan during starvation dependence on a genotype (17.62 % and 19.51 %), external factors (h = 17.02 % and 19.64 %) and on the combined factors – h = 4.37 % and 2.42 % (for males and males, respectively) was shown. Conclusions. Almost in all experimental variants caffeine and laser light induced the extension lifespan during starvation. The simultaneous applying of both factors (caffeine+laser light) induced the maximal lifespan extension in Drosophila stocks C-S, ebony, and ebonyOr. Such additive effect was not observed in ebonyC-S flies. We connect the observed effects of caffeine and laser light with hormesis effect.Keywords: drosophila, genotype, lifespan during starvation, mutation, stress tolerance.

The Drosophila Suppressor of Underreplication Protein Binds to Late-Replicating Regions of Polytene Chromosomes

In many late-replicating euchromatic regions of salivary gland polytene chromosomes, DNA is underrep-resented. A mutation in the SuUR gene suppresses underreplication and leads to normal levels of DNA polytenization in these regions. We identified the SuUR gene and determined its structure. In the SuUR mutant stock a 6-kb insertion was found in the fourth exon of the gene. A single SuUR transcript is present at all stages of Drosophila development and is most abundant in adult females and embryos. The SuUR gene encodes a protein of 962 amino acids whose putative sequence is similar to the N-terminal part of SNF2/SWI2 proteins. Staining of salivary gland polytene chromosomes with antibodies directed against the SuUR protein shows that the protein is localized mainly in late-replicating regions and in regions of intercalary and pericentric heterochromatin.

Notizen: A New Mutant Affecting Aldehyde Oxidase in Drosophila melanogaster

A new locus, Aldox-2, which affects the activity and heat stability of aldehyde oxidase in D. melanogaster is described. The Aldox-2 locus is localized to map position 86 on chromosome 2, between c and px. Aldehyde oxidase activity in Aldox-2 homozygotes is approximately 25 - 30% that of the Oregon-R wild-type control strain. The enzyme from the mutant stock is much more heat labile than is the enzyme from the wild-type strain. Both the activity and heat phenotypes are completely recessive.

THE EFFECTS OF LAO ON ALDEHYDE OXIDASE ACTIVITY AND CROSS-REACTING-MATERIAL IN DROSOPHILA MELANOGASTER

In Drosophila melanogaster aldehyde oxidase occurs in at least two forms that can be separated electrophoretically. The mutant allele lao (low aldehyde oxidase activity) causes a deficiency of the major form of this enzyme. Immunoelectrophoretic analyses suggest that lao homozygotes produce aldehyde oxidase cross-reacting-material in nearly wild-type levels. Although aldehyde oxidase from the mutant stock is heat labile, properties such as Km and pH optima are not different from the normal enzyme.

Graft-induced phenotypic changes in tomato mutants.

Reciprocal grafts were made between normal tomato lines and 36 mutants characterized by different leaf shape and colour or by shortened internodes. Some yellow-top mutants temporarily became darker green after grafting them on normal green stocks. The height of short-internode and of normal scions was only slightly affected by the genotype of the stock, and the genotype of the scion was expressed almost independently of the genotype of the stock. No evidence was found for any effects resulting from the movement of growth inhibiting or accelerating substances from stock to scion or from scion to stock. The same held true for substances inducing virus-like symptoms. In one graft combination normal scions on stocks of a short-internode mutant with a tendency to wilt were greatly reduced in total length, stem diameter and length of leaves. The mutant line grafted on a normal rootstock showed increased vigour. The effects of the mutant as well as of the normal type were expressed in one direction only, that is from stock to scion but not vice versa. The "wilty" condition was induced in a normal scion grafted on the mutant stock. Mutant scions grafted on normal stocks still showed signs of wilting. These effects are thought to result from a deficient transport system in the "wilty" mutant.-Hebrew Univ. of Jerusalem, Rehovot, and agric. Univ., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Some New Eye-Colour Changes in Gammarus cheureuxi Sexton. Part I

1. In a large number of experiments with Gammarus chevreuxi when the animals were kept under similar conditions at temperatures ranging from 20° to 28° C., twenty instances occurred in which red-eyed mutations appeared independently and simultaneously. The most important of these (Mutant Stock V) is described in detail in this paper.2. The Red eyes which have arisen in this Stock V and in the four previous Stocks, I to IV, have proved to be all genetically distinct from one another.3. There are at leadt two different classes of “red-eye,” the one simple, the other with intermediate stages. Mutant Stock V, here described, represents the second type. Differences in the method of origin of the two classes have been pointed out.4. The inheritance of the red-eyedness of the second class—namely, that in which intermediate stages and various colour changes occur—is of a complicated kind. For an interpretation in terms of Mendelian genes, even if allowance is made for an extent of variation in members of one particular genotype, clearly several of them are involved. Further, there must be considerable interplay of one kind or another among the different genes.5. Although so many different colour shades have appeared in Mutant Stock V, all can be interpreted in terms of varying concentrations of two pigments—the black and the red. Dilute black pigment with little or no red gives a purple eye.