DNA-synthesis in larval salivary glands during culture in starved female flies of Drosophila melanogaster

1975 ◽  
Vol 176 (4) ◽  
pp. 253-266 ◽  
Author(s):  
K. Weber ◽  
R. N�thiger
Keyword(s):  
Drosophila Melanogaster ◽  
Dna Synthesis ◽  
Salivary Glands

Initial phases of DNA synthesis in Drosophila melanogaster

Chromosoma ◽  
1974 ◽  
Vol 47 (4) ◽  
pp. 403-413 ◽  
Author(s):  
Klaus H�gele ◽  
Wolf -Ekkehard Kalisch
Keyword(s):  
Drosophila Melanogaster ◽  
Dna Synthesis

Studies on Nucleolar RNA Synthesis in Drosophila Melanogaster

1972 ◽  
Vol 11 (3) ◽  
pp. 689-697
Author(s):  
H. M. KRIDER ◽  
W. PLAUT
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Rna Synthesis ◽  
First Generation ◽  
Nucleolus Organizer ◽  
Fifth Generation ◽  
Autoradiographic Analysis ◽  
Temporally Correlated ◽  
Nucleolar Rna ◽  
Nucleolus Organizers

The influence of conditions resulting in bobbed phenotypes on nucleolar RNA synthesis and the formation of constrictions at nucleolus organizers was examined in larval tissues of Drosophila melanogaster. By means of [3H]uridine incorporation and autoradiographic analysis, a mutation at the bobbed locus was shown to limit the rate of nucleolar RNA synthesis in salivary glands of XO larvae. The formation of constrictions at the organizer sites of a 4-nucleolus-organizer stock was monitored in dividing neuroblast cells stained with acridine orange. Loss of the ribosomal cistrons had been reported by other workers when such stocks were maintained for several generations. In the first generation in our work, constrictions were visible at only 2 of the 4 nucleolus organizers. This situation persisted until the fifth generation, when constrictions appeared at all 4 of the organizer sites. An increase in the rate of nucleolar RNA synthesis in the salivary glands was temporally correlated with the appearance of the extra constrictions. We interpret these observations to mean that 2 of the organizers of the 4-nucleolus-organizer stock were caused to function through the loss of ribosomal RNA cistrons; thus the functional status of an organizer would appear to be subject to control.

Morphological and molecular modifications induced by heat shock in Drosophila melanogaster embryos

Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 167-182
Author(s):  
Giorgio Graziosi ◽  
Franco de Cristini ◽  
Angelo di Marcotullio ◽  
Roberto Marzari ◽  
Fulvio Micali ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Dna Synthesis ◽  
Histological Analysis ◽  
Developmental Stages ◽  
Early Embryo ◽  
Direct Relation ◽  
Hsp 70 ◽  
Survival Pattern ◽  
Shock Proteins

The early embryo of Drosophila melanogaster did not survive treatment at 37 °C (heat shock) for 25 min. The histological analysis of eggs treated in this way showed that the heat shock caused disintegration of nuclei and of cytoplasmic islands, displacement and swelling of nuclei and blocked mitoses. These effects were not observed in embryos treatedafter blastoderm formation. After this stage, we noticed that development was slowed down. The heat shock proteins (hsp 83,70 and 68) were, under shock, synthesized at all developmental stages. There was little or no synthesis of hsp 70 and 68 in unfertilized eggs, but synthesis increased in proportion to the number of nuclei present. Most probably, hsp 70 synthesis was directed by zygotic mRNA. DNA synthesis was not blocked by the heat shock though the overall incorporation of [3H]thymidine was substantially reduced, presumably because of the block of mitoses. We did not find a direct relation between survival pattern and hsp synthesis. We concluded that some, at least, of the heat shock genes can be activated at all developmental stages and that heat shock could be used for synchronizing mitoses.

scholarly journals Flying High—Muscle-Specific Underreplication in Drosophila

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 246 ◽  
Author(s):  
J. Spencer Johnston ◽  
Mary E. Zapalac ◽  
Carl E. Hjelmen
Keyword(s):  
Flow Cytometry ◽  
Dna Synthesis ◽  
Salivary Glands ◽  
Genome Size ◽  
Flight Muscle ◽  
S Phase ◽  
The Other ◽  
Tissue Type ◽  
Flight Muscles ◽  
Longitudinal Muscles

Drosophila underreplicate the DNA of thoracic nuclei, stalling during S phase at a point that is proportional to the total genome size in each species. In polytene tissues, such as the Drosophila salivary glands, all of the nuclei initiate multiple rounds of DNA synthesis and underreplicate. Yet, only half of the nuclei isolated from the thorax stall; the other half do not initiate S phase. Our question was, why half? To address this question, we use flow cytometry to compare underreplication phenotypes between thoracic tissues. When individual thoracic tissues are dissected and the proportion of stalled DNA synthesis is scored in each tissue type, we find that underreplication occurs in the indirect flight muscle, with the majority of underreplicated nuclei in the dorsal longitudinal muscles (DLM). Half of the DNA in the DLM nuclei stall at S phase between the unreplicated G0 and fully replicated G1. The dorsal ventral flight muscle provides the other source of underreplication, and yet, there, the replication stall point is earlier (less DNA replicated), and the endocycle is initiated. The differences in underreplication and ploidy in the indirect flight muscles provide a new tool to study heterochromatin, underreplication and endocycle control.

20-OH-ecdysone swells nuclear volume by alkalinization in salivary glands of Drosophila melanogaster

1993 ◽  
Vol 274 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Stefan W�nsch ◽  
Stefan Schneider ◽  
Albrecht Schwab ◽  
Hans Oberleithner
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Nuclear Volume

scholarly journals Acetylation of chromosome squashes of Drosophila melanogaster decreases the background in autoradiographs from hybridization with [125I]-labeled RNA.

1978 ◽  
Vol 26 (8) ◽  
pp. 677-679 ◽  
Author(s):  
S Hayashi ◽  
I C Gillam ◽  
A D Delaney ◽  
G M Tener
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Labeled Rna

DNA in prepared chromosomes from the larval salivary glands of Drosophila melanogaster was hybridized with [125I]-labeled 5S and tRNA from the same organism. Autoradiography revealed that radioactivity was frequently bound to all regions of the slides, masking labeling of the chromosomes. Acetylation of the preparations before hybridization prevented the formation of this background and revealed the specific chromosomal sites.

scholarly journals A plant DNA virus replicates in the salivary glands of its insect vector via recruitment of host DNA synthesis machinery

2020 ◽  
Vol 117 (29) ◽  
pp. 16928-16937 ◽  
Author(s):  
Ya-Zhou He ◽  
Yu-Meng Wang ◽  
Tian-Yan Yin ◽  
Elvira Fiallo-Olivé ◽  
Yin-Quan Liu ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Salivary Glands ◽  
Large Family ◽  
Plant Viruses ◽  
Nuclear Antigen ◽  
Insect Vector ◽  
Dna Virus ◽  
Dna Viruses ◽  
Plant Dna ◽  
Leaf Curl

Whereas most of the arthropod-borne animal viruses replicate in their vectors, this is less common for plant viruses. So far, only some plant RNA viruses have been demonstrated to replicate in insect vectors and plant hosts. How plant viruses evolved to replicate in the animal kingdom remains largely unknown. Geminiviruses comprise a large family of plant-infecting, single-stranded DNA viruses that cause serious crop losses worldwide. Here, we report evidence and insight into the replication of the geminivirus tomato yellow leaf curl virus (TYLCV) in the whitefly (Bemisia tabaci) vector and that replication is mainly in the salivary glands. We found that TYLCV induces DNA synthesis machinery, proliferating cell nuclear antigen (PCNA) and DNA polymerase δ (Polδ), to establish a replication-competent environment in whiteflies. TYLCV replication-associated protein (Rep) interacts with whitefly PCNA, which recruits DNA Polδ for virus replication. In contrast, another geminivirus, papaya leaf curl China virus (PaLCuCNV), does not replicate in the whitefly vector. PaLCuCNV does not induce DNA-synthesis machinery, and the Rep does not interact with whitefly PCNA. Our findings reveal important mechanisms by which a plant DNA virus replicates across the kingdom barrier in an insect and may help to explain the global spread of this devastating pathogen.

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