Balbiani rings and puffs of the polytene chromosomes of Drosophila auraria

Chromosoma ◽  
1984 ◽  
Vol 89 (2) ◽  
pp. 96-106 ◽  
Author(s):  
Zacharias G. Scouras ◽  
Costas D. Kastritsis
Keyword(s):  
Polytene Chromosomes ◽  
Balbiani Rings

scholarly journals Balbiani ring hnRNP substructure visualized by selective staining and electron spectroscopic imaging.

1992 ◽  
Vol 117 (3) ◽  
pp. 483-491 ◽  
Author(s):  
A L Olins ◽  
D E Olins ◽  
D P Bazett-Jones
Keyword(s):  
Nucleic Acid ◽  
Polytene Chromosomes ◽  
Particle Diameter ◽  
Balbiani Ring ◽  
Electron Spectroscopic Imaging ◽  
Selective Staining ◽  
Elemental Imaging ◽  
Mature Transcript ◽  
Balbiani Rings ◽  
Relationship Of

The Balbiani Rings (BR) in the polytene chromosomes of Chironomus salivary glands are intense sites of transcription. The nascent RNPs fold during transcription into 40-50-nm granules, containing in the mature transcript approximately 37-kb RNA. Using a new nucleic acid specific stain, osmium ammine B on Lowicryl sections, in combination with electron energy filtered imaging of sections containing BR granules, we demonstrate a RNA-rich particulate substructure (10-nm particle diameter; 10-12 particles per BR granule). Elemental imaging supports that these particles are enriched in phosphorus. The possible relationship of these RNA-rich particles to ribonucleosomes is discussed, as well as models for their arrangement in the mature BR granules.

Cytotaxonomic differentiation of the Afrotropical Drosophila montium subgroup: D. diplacantha and D. seguyi. The major role of reverse tandem duplications

Genome ◽  
1994 ◽  
Vol 37 (6) ◽  
pp. 935-944 ◽  
Author(s):  
P. Mavragani-Tsipidou ◽  
A. Zambetaki ◽  
K. Kleanthous ◽  
E. Pangou ◽  
Z. G. Scouras
Keyword(s):  
Polytene Chromosomes ◽  
Balbiani Ring ◽  
Developmental Profile ◽  
Intraspecific Polymorphism ◽  
Balbiani Rings ◽  
Chromosome Maps ◽  
Temporal And Spatial ◽  
Montium Subgroup ◽  
Tandem Duplications

Aiming to establish phylogenetic relationships among species of the montium subgroup, detailed polytene chromosome maps are given showing intraspecific polymorphism and ecdysone induced larval puffing pattern profiles of two Afrotropical members of this subgroup, Drosophila diplacantha and D. seguyi. Both species exhibit two unique characteristics that define the montium subgroup, namely, a large number of reverse tandem duplications and a progressive darkening of anterior spiracles of the late third instar larvae, which is accompanied by a definite temporal and spatial puffing pattern of the salivary gland chromosomes. In contrast with the well-formed Balbiani ring 1 (BR1) observed in Oriental and Indian montium species, BR1 exhibits a different developmental profile in D. diplacantha, while it is obscured in D. seguyi. Although phyletic comparisons of five species from five different complexes within the subgroup show some conservation in banding and puffing pattern homologies, an analysis to assign map sections by sequential rearrangements remains unresolved at this time. The evolution of the subgroup is discussed in relation with the sharing of reverse tandem duplications, especially those including the montium BRs.Key words: Drosophila montium, polytene chromosomes, Balbiani rings, puffs, duplications, inversions.

Ultrastructural Studies of Isolated Polytene Chromosomes by Scanning Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 196-197
Author(s):  
Michael B. Payne
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Polytene Chromosomes ◽  
Mitotic Chromosomes ◽  
Characteristic Appearance ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Balbiani Rings ◽  
Chromatin Fibers ◽  
Scanning Electron

Scanning and transmission electron microscopy studies of mitotic chromosomes have demonstrated that these chromosomes are composed of single intricately coiled and folded chromatin fibers 200-300 A in diameter (1). Transmission electron microscopy studies (2) have shown similar fibers in dipteran polytene chromosomes. It has been proposed that these fibers are extended in the less densely appearing interband regions and become more tightly coiled or folded at specific sites to produce the densely appearing banded regions (3). With the scanning electron microscope it is now possible to observe the characteristic appearance of the chromatin fibers in the band and interband regions of isolated intact polytene chromosomes. Furthermore, the morphology of the nucleolus and Balbiani rings can be observed as specialized structures in the chromosome.

Homology of Balbiani rings among chironomid species and localization of a new mobile element on the polytene chromosomes

1992 ◽  
Vol 26 (2-4) ◽  
pp. 123-128 ◽  
Author(s):  
M. A. Filippova ◽  
I. I. Kiknadze ◽  
K. G. Aimanova ◽  
J. Fischer ◽  
A. G. Blinov
Keyword(s):  
Polytene Chromosomes ◽  
Mobile Element ◽  
Chironomid Species ◽  
Balbiani Rings

An ultrastructural and histochemical developmental study of Drosophila auraria salivary gland cells during the third-instar period

1989 ◽  
Vol 67 (2) ◽  
pp. 421-429 ◽  
Author(s):  
George N. Thomopoulos ◽  
Eleftherios P. Neophytou ◽  
Costas D. Kastritsis
Keyword(s):  
Salivary Gland ◽  
Electron Density ◽  
Developmental Stages ◽  
Secretory Granules ◽  
Polytene Chromosomes ◽  
Developmental Study ◽  
The Third ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Balbiani Rings

Early in the third-instar stage of Drosophila auraria, the salivary gland cells produce small secretory granules of low electron density which empty their flocculent contents into the lumen of the gland. At that stage, the Golgi complexes consist of vesiculated, round cisternae which, as middle third instar is approached, change to their classical appearance. Cytoplasmic protrusions, intramitochondrial granules, and close contacts of mitochondria with lipid droplets are observed during the early developmental stages. At about the middle of the third instar the glue secretory granules start being produced. These secretory granules contain a granular material (where small amounts of vicinal glycol and sulfated groups of complex carbohydrates have been detected) of medium electron density. The glue secretory granules can be classified according to their electron density into two populations. Before exocytosis large amounts of glycogen particles are observed, providing some of the energy needed during the final step of exocytosis. Two different types of ribonucleoprotein particles in puffing sites of the chromosomes are observed. Of these, the larger ones consist of a core surrounded by smaller particles; we suspect that they may be produced in the Balbiani rings observed in the polytene chromosomes of this species. Nuclear blebs and oval bodies are common, particularly during the late developmental stages. The functional significance of these findings during development is discussed.

Selective stimulation of puffing activity in vitro with a juvenile hormone analogue by polytene chromosomes in the salivary glands of Chironomus thummi (Diptera)

1989 ◽  
Vol 67 (10) ◽  
pp. 2528-2532
Author(s):  
X. Vafopoulou ◽  
C. G. H. Steel ◽  
H. Laufer
Keyword(s):  
Juvenile Hormone ◽  
Salivary Glands ◽  
Polytene Chromosomes ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Balbiani Rings ◽  
Chironomus Thummi ◽  
Stimulation Of

Salivary glands of Chironomus thummi prepupae were treated in vitro with various concentrations of the juvenile hormone analogue (JHA) methoprene and the puffing activities of Balbiani rings (BR) b and c were scored in cytological preparations of polytene chromosomes. In control cultures, both BRb and BRc regress rapidly. JHA treatment in vitro prevented regression at both these sites. In addition, BRb was found to expand within 60 min to a size two to three times larger than in control contralateral glands. The most effective concentration for stimulation of BRb and BRc in vitro was 10−7 M. In vivo treatment of prepupae with 10−7 M JHA also induced puffing activity in BRb and BRc to a degree similar to that observed following in vitro treatment. It is concluded that BRb, and perhaps also BRc, are juvenile hormone (JH) inducible chromosomal sites in Chironomus thummi salivary glands. This is the first report of chromosomal sites that are stimulated by JH in vitro in the absence of exogenous ecdysteroids. These findings support the view that JH may act at the gene level at separate loci from ecdysone.

scholarly journals Chironomus (diptera) polytene chromosomes functional activity under the influence of cholinotropic preparations

2009 ◽  
Vol 7 (3) ◽  
pp. 44-52
Author(s):  
Irina A Fyodorova ◽  
Natalia V Polukonova ◽  
Konstantin N Dvoretsky ◽  
Svetlana I Bogoslovskaya
Keyword(s):  
Morphometric Analysis ◽  
Functional Activity ◽  
Polytene Chromosomes ◽  
Nucleolar Organizer ◽  
Antagonistic Effect ◽  
B Chromosomes ◽  
Activity Change ◽  
Balbiani Rings ◽  
Chromosome I ◽  
Period Duration

Morphometric analysis of nucleolar organizer (NO), Balbiani rings (BR) - BR<sub>B</sub>, BR<sub>1G</sub>, BR<sub>2G</sub>, chromosome I arm puff B, chromosomes compactness activity change under the influence of cholinotropic preparations was carried out. Most sensitive criterion - chromosomes compactness is, most stable under the influence of stress - NO is. Atropine and pilocarpine antagonistic effect on the polytene chromosomes (PC) sites activity pilocarpine manifested itself in functional activity and restoration period duration change: on cholinoblocker effect activity decreased, while on cholinomimetic effect activity increased.

scholarly journals Evaluation of the Sensitivity of the Terminal Deoxynucleotidyl Transferase–Immunogold Technique on Balbani Ring Genes

1998 ◽  
Vol 46 (3) ◽  
pp. 345-351 ◽  
Author(s):  
Marc Thiry ◽  
Bertil Daneholt
Keyword(s):  
Polytene Chromosomes ◽  
High Sensitivity ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Immunogold Technique ◽  
Active Transcription ◽  
Balbiani Rings ◽  
In Situ Detection ◽  
Single Dna Molecule ◽  
Very High

Recently, we developed the terminal deoxynucleotidyl transferase (TdT)–immunogold technique for in situ detection of DNA molecules. In this study the potential value and the limitations of the method were evaluated using the giant polytene chromosomes from Chironomus tentans salivary glands. Emphasis was put on the Balbiani rings (BRs), specialized chromosomal sites with exceptionally intense synthesis of large mRNA molecules. Immunolabeling was recorded not only over the bands and interbands of the polytene chromosomes but also over the BR structures. In the BRs, gold particles were present over segments of active transcription units, each with a central chromatin axis and a number of growing RNP products attached to the axis. One third of the transversely sectioned transcription units showed labeling in the central parts, i.e., where the unfolded chromatin axis is located, whereas the growing RNP fibers remained unlabeled. The absence of labeling of the RNP fibers is not likely to be due to lack of accessibility, because anti-RNA antibodies readily decorated the RNP fibers. The nuclear sap and cytoplasm displayed no significant label. These results clearly indicate that the TdT–immunogold technique is specific for DNA and detects not only DNA in compacted chromatin but also fully extended DNA. Its ability to efficiently label a single DNA molecule demonstrates the method's very high sensitivity.

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