scholarly journals Peculiarities of conjugation of polytene chromosomes in the offspring of Drosophila melanogaster Meig. after exposure to the acute γ-irradiation

1970 ◽  
pp. 314-318
Author(s):  
D. A. Skorobahatko ◽  
V. Yu. Strashnyuk ◽  
A. A. Mazilov
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Polytene Chromosomes ◽  
Wild Type ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Homologous Chromosomes ◽  
Salivary Gland Cells ◽  
F1 Progeny ◽  
High Degree

Aim. The purpose of investigation was to study the peculiarities of homologous conjugation of polytene chromosomes in the salivary glands of larvae in Drosophila melanogaster offspring after exposure to acute γ-irradiation. Methods. Experiments were carried out on wild type Oregon-R strain. Three-day-old flies were irradiated by brake gamma rays on the linear electron accelerator LEA-10. The dose rate was 0.4 Gr/sec.The effects of acute γ-radiation at doses of 8 Gr and 16 Gr were studied. Giant chromosomes were investigated in squashed preparations of the salivary glands stained by acetoorcein. Preparations were obtained from the females at the end of third larva stage. Results. The decrease at 41.5 % in asynapsis frequency of homologous chromosomes in salivary gland cells of larvae in Drosophila F1 progeny after γ-irradiation at the dose of 8 Gr was shown. No effect was observed at the dose of 16 Gr. Analysis of variance showed with a high degree of significance (Fφ = 53, p < 0,001) the influence of gradations of factor on the frequency of violations of conjugation of homologous in Drosophila polytene chromosomes. Conclusions. The results suggest a possible effect of gamma-radiation on the trans-interaction of loci of homologous chromosomes due to the changes in the asynapsis frequency. Keywords: giant chromosomes, spontaneous asynapsis, trans-interactions, ionizing radiation.

scholarly journals Puffing activity in Drosophila melanogaster Meig. political chromosomes after exposure to microwave radiation

2018 ◽  
Vol 23 ◽  
pp. 393-398
Author(s):  
M. N. Sheyka ◽  
V. Yu. Strashnyuk
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Power Density ◽  
Microwave Radiation ◽  
X Chromosome ◽  
Polytene Chromosomes ◽  
Early Embryogenesis ◽  
Wild Type ◽  
Ocular Micrometer ◽  
Outbred Strain

Aim. The aim of the work was to study the effect of microwave radiation of varying intensity on the polytene chromosomes puffing activity in larvae salivary glands of Drosophila melanogaster. Methods. The wild type outbred strain Oregon-R was used as the material. Microwave radiation with a frequency of 36.64 GHz and a power density of 0.1 and 1 W / m2 was used. Exposure to microwaves was applied in early embryogenesis after 3-hour oviposition. Exposure time was 30 sec. The puff sizes were studied on the squashed preparations of larvae salivary glands stained with acetoorcein. Dimensions of four puffs were investigated^ 2B5-6 (X chromosome); 62E, 71CE and 72CD (chromosome 3L). The measurements were carried out using an ocular-micrometer. Results. There were no significant changes in the size of the puffs in any of the four loci studied, regardless of the applied power density. Conclusions. Microwave radiation in early embryogenesis at a frequency of 36.64 GHz, a power density of 0.1 and 1 W/m2, and an exposure of 30 sec does not have a significant effect on the puff sizes in the Drosophila polytene chromosomes. Keywords: Drosophila melanogaster Meig., giant chromosomes, puff sizes, non-ionizing radiation.

A comparison of polytene chromosomes in salivary glands and orbital bristle trichogen cells in Ceratitis capitata

Genome ◽  
1991 ◽  
Vol 34 (2) ◽  
pp. 215-219 ◽  
Author(s):  
A. Zacharopoulou ◽  
K. Bourtzis ◽  
Ph. Kerremans
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Banding Pattern ◽  
Ceratitis Capitata ◽  
Polytene Chromosomes ◽  
Biological Significance ◽  
Fruit Fly ◽  
Banding Patterns ◽  
Homologous Chromosomes ◽  
Different Tissues

The banding patterns of polytene chromosomes in different tissues of the Mediterranean fruit fly, Ceratitis capitata, vary to such an extent that homologous chromosomes cannot be recognised. However, analyses of autosomal breakpoints in several translocation strains allowed chromosomes from the two tissues to be aligned despite their difference in banding pattern. These results were discussed, considering the different hypotheses of the origin and biological significance of polytene chromosome bands.Key words: polytene chromosomes, salivary gland chromosomes, orbital bristle trichogen cell chromosomes, Ceratitis capitata.

scholarly journals Reproduction and endoreduplication in Drosophila melanogaster Meig. when influenced by lead nitrate

2020 ◽  
Vol 27 ◽  
pp. 303-308
Author(s):  
V. Yu. Strashnyuk ◽  
O. V. Taglina
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Type Strain ◽  
Wild Type Strain ◽  
Lead Nitrate ◽  
Wild Type ◽  
Reproductive Ability ◽  
Dose Dependent Decrease ◽  
Drosophila Cells ◽  
Dose Dependent

Aim. The purpose of investigation was to study the reproductive ability and polyteny degree of chromosomes in Drosophila melanogaster Meig. under the influence of various concentrations of lead nitrate. Methods. Canton-S wild-type strain was used as the material. Flies developed on standard sugar-yeast medium, to which in the experiment lead nitrate was added in concentrations of 0.1, 1, and 10 mg/ml. The reproductive ability of the strain was evaluated by the number of adult offspring. The polyteny degree of chromosomes was studied on squashed preparations of larva salivary glands stained with acetoorsein by cytomorphometry. The preparations were obtained at late 3rd instar. Results. The number of adult offsprings decreased when lead nitrate was added to the nutrient medium: at a concentration of 0.1 mg/ml – by 22.8 %, at 1 mg/ml – by 38.9 %. A concentration of 10 mg/ml was lethal. Males showed greater sensitivity to the drug compared to females. The degree of polyteny of chromosomes in the salivary glands of larvae decreased on average by 5.0–6.5 %. Conclusions. Lead nitrate causes a significant, dose-dependent decrease in the reproductive ability of fruit flies and has a toxic effect on Drosophila cells, inhibiting the process of endoreduplication. Keywords: Drosophila melanogaster Meig., heavy metals, fecundity, giant chromosomes, polyteny.

LARVAL AGE AND THE PATTERN OF DNA SYNTHESIS IN POLYTENE CHROMOSOMES

1968 ◽  
Vol 10 (1) ◽  
pp. 82-90 ◽  
Author(s):  
David Nash ◽  
John Bell
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Dna Synthesis ◽  
Polytene Chromosomes ◽  
Larval Life ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Puparium Formation ◽  
Chromosome Ii ◽  
Replicative Cycle

It has been shown, by autoradiography using H3-thymidine, that the frequency of salivary gland cells where DNA synthesis covers the entire length of a specific polytene chromosomal segment (Chromosome II, 56F-60A, Drosophila melanogaster) drops off some time during the last day of larval life. The frequency of highly discontinuous DNA synthesis over the same region remains at about the same level until a stage closer to puparium formation, when all DNA synthesis stops.If a cycle of DNA synthesis, once initiated, goes to completion, then this finding indicates that the patterns of spatially continuous synthesis tend to occur early in the replicative cycle and that the terminal phases of the cycle involve highly discontinuous patterns of synthesis.

scholarly journals Ultrastructural histochemical localization of acid phosphatase in salivary glands of Drosophila melanogaster.

1976 ◽  
Vol 24 (2) ◽  
pp. 463-467 ◽  
Author(s):  
J Anastasia-Sawicki ◽  
R J MacIntyre
Keyword(s):  
Drosophila Melanogaster ◽  
Acid Phosphatase ◽  
Salivary Glands ◽  
Incubation Time ◽  
Reaction Medium ◽  
Histochemical Localization ◽  
Wild Type ◽  
Lead Phosphate ◽  
Final Reaction Product ◽  
Optimal Incubation

The ultrastructural histochemical localization of acid phosphatase in salivary glands of third instar larvae of Drosophila melanogaster has been studied. Using Gomori's lead phosphate method for acid phosphatase detection, the optimal incubation time in the reaction medium was determined to be 30 min. When glands having wild-type acid phosphatase activity are incubated for this time, deposition of the final reaction product is observed in essentially every lysosome and artifactual staining is minimal.

scholarly journals Selection index in Drosophila melanogaster Meig. progeny after exposure to acute γ-irradiation

2019 ◽  
Vol 25 ◽  
pp. 86-91
Author(s):  
D. O. Skorobagatko ◽  
V. Yu. Strashnyuk ◽  
A. A. Mazilov
Keyword(s):  
Drosophila Melanogaster ◽  
Linear Accelerator ◽  
Selection Pressure ◽  
First Generation ◽  
Selection Index ◽  
Control Level ◽  
Wild Type ◽  
Γ Irradiation ◽  
Two Generations ◽  
Selection Indexes

Aim. The purpose of investigation was to study the intensity of selection in two generations of Drosophila melanogaster Meig. after acute g-irradiation. Methods. Experiments were conducted on a wild-type Oregon-R strain. Adult flies in the age of 3 days were irradiated with bremsstrahlung gamma quanta at doses of 8 Gy, 16 Gy and 25 Gy on a linear accelerator of electrons LAE-10. Irradiated (O) and non-irradiated (K) flies were crossed in four different combinations: K×K (control), O×K, K×O, and O×O. The selection index were calculated from the Crow formula based on fertility, mortality/survival in pre-productive period of development. Results. Selection indexes in the generation F1 after irradiation grow in proportion to the dose received: at embryonal stage 2.0–7.2 times, at post-embryonic development – in 1.3–7.6 times. In the generation F2, the indexes of selection were significantly reduced. Conclusions. The selection pressure is substantially increased in the first generation after g-irradiation and weakens, approaching the control level and lower in F2. Keywords: Drosophila melanogaster Meig., fertility, embryonic mortality, pupae mortality, ionizing radiation.

scholarly journals Deletion of Puma protects hematopoietic stem cells and confers long-term survival in response to high-dose γ-irradiation

Blood ◽  
2010 ◽  
Vol 115 (17) ◽  
pp. 3472-3480 ◽  
Author(s):  
Hui Yu ◽  
Hongmei Shen ◽  
Youzhong Yuan ◽  
Richard XuFeng ◽  
Xiaoxia Hu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Bone Marrow Cells ◽  
High Dose ◽  
Wild Type ◽  
Γ Irradiation ◽  
Term Survival ◽  
Hematopoietic Stem ◽  
Γ Radiation

Abstract Molecular paradigms underlying the death of hematopoietic stem cells (HSCs) induced by ionizing radiation are poorly defined. We have examined the role of Puma (p53 up-regulated mediator of apoptosis) in apoptosis of HSCs after radiation injury. In the absence of Puma, HSCs were highly resistant to γ-radiation in a cell autonomous manner. As a result, Puma-null mice or the wild-type mice reconstituted with Puma-null bone marrow cells were strikingly able to survive for a long term after high-dose γ-radiation that normally would pose 100% lethality on wild-type animals. Interestingly, there was no increase of malignancy in the exposed animals. Such profound beneficial effects of Puma deficiency were likely associated with better maintained quiescence and more efficient DNA repair in the stem cells. This study demonstrates that Puma is a unique mediator in radiation-induced death of HSCs. Puma may be a potential target for developing an effective treatment aimed to protect HSCs from lethal radiation.

scholarly journals Chiasmata in spermatocytes of Drosophila melanogaster

1964 ◽  
Vol 5 (1) ◽  
pp. 80-84 ◽  
Author(s):  
B. M. Slizynski
Keyword(s):  
Drosophila Melanogaster ◽  
Type Strain ◽  
Wild Type Strain ◽  
Chromosome Behaviour ◽  
Wild Type ◽  
Homologous Chromosomes ◽  
Translocation Heterozygote ◽  
Positive Material ◽  
Chromosome Material

On the basis of chromosome behaviour in three strains of Drosophila melanogaster males—a wild-type strain, a translocation heterozygote strain and a double translocation strain—it is concluded that the cytologically detected apparent chiasmata in the autosomes are only surface associations of homologous chromosomes and do not involve exchange of chromosome material. Such chiasma-like associations occur also between non-homologous chromosomes. The stainable, Feulgen-positive material of the chromosomes is thought to be responsible for the surface associations.

scholarly journals Involvement of the MKK6-p38γ Cascade in γ-Radiation-Induced Cell Cycle Arrest

2000 ◽  
Vol 20 (13) ◽  
pp. 4543-4552 ◽  
Author(s):  
Xiaofei Wang ◽  
Clare H. McGowan ◽  
Ming Zhao ◽  
Liusheng He ◽  
Jocelyn S. Downey ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Dominant Negative ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Cycle Arrest ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Radiation Induced ◽  
High Degree ◽  
Degree Of Similarity

ABSTRACT The p38 group of kinases belongs to the mitogen-activated protein (MAP) kinase superfamily with structural and functional characteristics distinguishable from those of the ERK, JNK (SAPK), and BMK (ERK5) kinases. Although there is a high degree of similarity among members of the p38 group in terms of structure and activation, each member appears to have a unique function. Here we show that activation of p38γ (also known as ERK6 or SAPK3), but not the other p38 isoforms, is required for γ-irradiation-induced G2arrest. Activation of the MKK6-p38γ cascade is sufficient to induce G2 arrest in cells, and expression of dominant negative alleles of MKK6 or p38γ allows cells to escape the DNA damage-induce G2 delay. Activation of p38γ is dependent on ATM and leads to activation of Cds1 (also known as Chk2). These data suggest a model in which activation of ATM by γ irradiation leads to the activation of MKK6, p38γ, and Cds1 and that activation of both MKK6 and p38γ is essential for the proper regulation of the G2checkpoint in mammalian cells.

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