Limits...
A new nucleolar body appears in Drosophila saltans salivary gland cells before histolysis, in programmed cell death.

de Oliveira CC, de Campos Bicudo HE - J. Insect Sci. (2006)

Bottom Line: In many cells, the new nucleolar corpuscle and these chromosome threads are associated.These findings are novel.However, the hypothesis put forward concerning their meaning remains dependent on other studies.

View Article: PubMed Central - PubMed

Affiliation: Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA. cdeolive@uark.edu

ABSTRACT
The salivary glands of Drosophila saltans (saltans group, saltans subgroup) analyzed in an advanced stage of programmed cell death showed the appearance of a single, round, nucleolar corpuscle inside the highly altered nucleus of every gland cell, at a time during which the integrity of the original nucleolus was already lost and the original nucleolar material apparently disappeared. In the same nuclei, which already had also lost the characteristic chromosome structure, some delicate chromosome threads were maintained. In many cells, the new nucleolar corpuscle and these chromosome threads are associated. These findings are novel. However, the hypothesis put forward concerning their meaning remains dependent on other studies.

Show MeSH

Related in: MedlinePlus

A-F. Salivary gland cells in different stages of the programmed cell death. A. Normal chromosome set (three chromosome pairs) in a third instar, lacto-acetic orcein stained larva cell. B-E. AG-stained cells. B. Normal nucleolus in third instar larva. C. Normal nucleolus associated with the nucleolar organizer region by DNA threads (arrow). D, E. Patterns of Ag-staining of the nucleolus (arrows) in different moments of programmed cell death: D. staining restrict to the nucleolar center; E. The nucleolus already lost its round shape, masses of stained nucleolar material being spread over and between masses of chromosome material. F. Phase contrast, lacto-acetic orcein. The chromosomes in advanced stage of structural change. Cr = chromocenter; Nu = nucleolus. Scale bars: A = 10 µm; B = 2.5 µm; C = 4.7 µm, D = 7.0 µm; E, F = 3.2 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2990330&req=5

f01: A-F. Salivary gland cells in different stages of the programmed cell death. A. Normal chromosome set (three chromosome pairs) in a third instar, lacto-acetic orcein stained larva cell. B-E. AG-stained cells. B. Normal nucleolus in third instar larva. C. Normal nucleolus associated with the nucleolar organizer region by DNA threads (arrow). D, E. Patterns of Ag-staining of the nucleolus (arrows) in different moments of programmed cell death: D. staining restrict to the nucleolar center; E. The nucleolus already lost its round shape, masses of stained nucleolar material being spread over and between masses of chromosome material. F. Phase contrast, lacto-acetic orcein. The chromosomes in advanced stage of structural change. Cr = chromocenter; Nu = nucleolus. Scale bars: A = 10 µm; B = 2.5 µm; C = 4.7 µm, D = 7.0 µm; E, F = 3.2 µm.

Mentions: D. saltans has three polytene chromosome pairs, two metacentric-chromosomes X and II, and one acrocentric-chromosome III, all of them linked by the centromeric region forming the chromocenter (Figure 1A). As in most Drosophila species in the late third instar, the characteristic transverse pattern of bands and interbands along the length of the chromosomes was well defined, except in the heterochromatic centromeric region. At this developmental stage each salivary gland cell showed a large, single, round or oval nucleolus that stained strongly brown with silver nitrate and had a heterogeneous structure, as described using light and electron microscopy in several organisms (e.g., Bernhard 1966; Thiry and Goessens 1996). Chromatin threads linked the nucleolus to the nucleolar organizing region, which in D. saltans was located in the centromeric region of the X chromosome (Bicudo 1973) (Figure 1B, C). In Drosophila, these chromatin threads that are associated with the nucleolus stain brown with silver nitrate and are marked with rRNA by in situ hybridization (Bicudo 1981; Bicudo and Richardson 1981).


A new nucleolar body appears in Drosophila saltans salivary gland cells before histolysis, in programmed cell death.

de Oliveira CC, de Campos Bicudo HE - J. Insect Sci. (2006)

A-F. Salivary gland cells in different stages of the programmed cell death. A. Normal chromosome set (three chromosome pairs) in a third instar, lacto-acetic orcein stained larva cell. B-E. AG-stained cells. B. Normal nucleolus in third instar larva. C. Normal nucleolus associated with the nucleolar organizer region by DNA threads (arrow). D, E. Patterns of Ag-staining of the nucleolus (arrows) in different moments of programmed cell death: D. staining restrict to the nucleolar center; E. The nucleolus already lost its round shape, masses of stained nucleolar material being spread over and between masses of chromosome material. F. Phase contrast, lacto-acetic orcein. The chromosomes in advanced stage of structural change. Cr = chromocenter; Nu = nucleolus. Scale bars: A = 10 µm; B = 2.5 µm; C = 4.7 µm, D = 7.0 µm; E, F = 3.2 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2990330&req=5

f01: A-F. Salivary gland cells in different stages of the programmed cell death. A. Normal chromosome set (three chromosome pairs) in a third instar, lacto-acetic orcein stained larva cell. B-E. AG-stained cells. B. Normal nucleolus in third instar larva. C. Normal nucleolus associated with the nucleolar organizer region by DNA threads (arrow). D, E. Patterns of Ag-staining of the nucleolus (arrows) in different moments of programmed cell death: D. staining restrict to the nucleolar center; E. The nucleolus already lost its round shape, masses of stained nucleolar material being spread over and between masses of chromosome material. F. Phase contrast, lacto-acetic orcein. The chromosomes in advanced stage of structural change. Cr = chromocenter; Nu = nucleolus. Scale bars: A = 10 µm; B = 2.5 µm; C = 4.7 µm, D = 7.0 µm; E, F = 3.2 µm.
Mentions: D. saltans has three polytene chromosome pairs, two metacentric-chromosomes X and II, and one acrocentric-chromosome III, all of them linked by the centromeric region forming the chromocenter (Figure 1A). As in most Drosophila species in the late third instar, the characteristic transverse pattern of bands and interbands along the length of the chromosomes was well defined, except in the heterochromatic centromeric region. At this developmental stage each salivary gland cell showed a large, single, round or oval nucleolus that stained strongly brown with silver nitrate and had a heterogeneous structure, as described using light and electron microscopy in several organisms (e.g., Bernhard 1966; Thiry and Goessens 1996). Chromatin threads linked the nucleolus to the nucleolar organizing region, which in D. saltans was located in the centromeric region of the X chromosome (Bicudo 1973) (Figure 1B, C). In Drosophila, these chromatin threads that are associated with the nucleolus stain brown with silver nitrate and are marked with rRNA by in situ hybridization (Bicudo 1981; Bicudo and Richardson 1981).

Bottom Line: In many cells, the new nucleolar corpuscle and these chromosome threads are associated.These findings are novel.However, the hypothesis put forward concerning their meaning remains dependent on other studies.

View Article: PubMed Central - PubMed

Affiliation: Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA. cdeolive@uark.edu

ABSTRACT
The salivary glands of Drosophila saltans (saltans group, saltans subgroup) analyzed in an advanced stage of programmed cell death showed the appearance of a single, round, nucleolar corpuscle inside the highly altered nucleus of every gland cell, at a time during which the integrity of the original nucleolus was already lost and the original nucleolar material apparently disappeared. In the same nuclei, which already had also lost the characteristic chromosome structure, some delicate chromosome threads were maintained. In many cells, the new nucleolar corpuscle and these chromosome threads are associated. These findings are novel. However, the hypothesis put forward concerning their meaning remains dependent on other studies.

Show MeSH
Related in: MedlinePlus