Immunoelectron microscope localization of snRNPs in the polytene nucleus of salivary glands ofChironomus thummi

Chromosoma ◽  
1990 ◽  
Vol 99 (1) ◽  
pp. 44-51 ◽  
Author(s):  
G. H. Vazquez-Nin ◽  
O. M. Echeverria ◽  
S. Fakan ◽  
G. Leser ◽  
T. E. Martin
Keyword(s):  
Salivary Glands ◽  
Polytene Nucleus

A new type of ribonucleoprotein constituent of the polytene nucleus of the salivary glands ofChironomus thummi andCh. tentans

Chromosoma ◽  
1993 ◽  
Vol 102 (10) ◽  
pp. 693-699 ◽  
Author(s):  
G. H. V�zquez-Nin ◽  
O. M. Echeverr�a ◽  
V. Boutinard Rouelle-Rossier ◽  
S. Fakan
Keyword(s):  
Salivary Glands ◽  
New Type ◽  
Polytene Nucleus

Patterns of DNA replication in Drosophila polytene nuclei replicating in Xenopus egg and oocyte extracts

1992 ◽  
Vol 101 (3) ◽  
pp. 509-515
Author(s):  
A.M. Sleeman ◽  
G.H. Leno ◽  
A.D. Mills ◽  
M.P. Fairman ◽  
R.A. Laskey
Keyword(s):  
Dna Replication ◽  
Salivary Glands ◽  
High Speed ◽  
De Novo ◽  
Replication Forks ◽  
Egg Extract ◽  
Replication Foci ◽  
Sperm Nuclei ◽  
Polytene Nucleus ◽  
Polytene Nuclei

We have used Xenopus laevis cell-free extracts to study patterns of DNA replication in polytene nuclei isolated from salivary glands of Drosophila melanogaster 3rd instar larvae. Replication was visualized by supplementation with biotin-dUTP so that nascent DNA became labelled, thus allowing detection with fluorescein or Texas-Red-conjugated streptavidin. Biotin incorporation was dependent on incubation in extracts. Transverse bands were labelled in high-speed supernatants of eggs or oocytes in which replication does not initiate de novo. These patterns corresponded to the patterns of endogenous replication forks in polytene nuclei, monitored by bromodeoxyuridine incorporation in intact salivary glands. By contrast, when nuclei were incubated in low-speed supernatants of eggs, they underwent more extensive chromatin decondensation and initiated replication. The spatial patterns of replication are strikingly different from the endogenous patterns. Instead they closely resemble patterns of clustered replication forks seen in Xenopus sperm nuclei replicating in the extract. This indicates that the egg extract can impose its pattern of replication foci even when the template is presented in the highly organized form of a polytene nucleus.

scholarly journals The three-dimensional organization of polytene nuclei in male Drosophila melanogaster with compound XY or ring X chromosomes.

Genetics ◽  
1989 ◽  
Vol 121 (2) ◽  
pp. 293-311
Author(s):  
D Mathog ◽  
J W Sedat
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
X Chromosome ◽  
Genetic Regulation ◽  
Polytene Chromosomes ◽  
Three Dimensional ◽  
X Chromosomes ◽  
Frequent Failure ◽  
Polytene Nucleus ◽  
Polytene Nuclei

Abstract The three-dimensional organization of polytene chromosomes within nuclei containing rearranged X chromosomes was examined in male Drosophila melanogaster. Salivary glands of third instar larvae containing either an inverted X chromosome (YSX.YL, In(1)EN/O) or a ring X chromosome (R(1) 2/BSYy+) were fixed, embedded, and serially sectioned. The nuclei in contiguous groups of cells were modeled and analyzed. We find that for both genotypes the three-dimensional behavior at each euchromatic locus is independent of the orientation of the chromosome on which it resides, independent of the behavior of loci not closely linked to it, and not similar in neighboring cells. The preference for right-handed chromosome coiling noted in previous studies is shown to be independent of homologous pairing. However, a relation between the extent of chromosome curvature and the handedness of chromosome coiling is present only in homologously paired chromosomes. The attached-XY chromosome has two previously undescribed behaviors: a nearly invariant association of the euchromatic side of the proximal heterochromatin/euchromatin junction with the nucleolus and a frequent failure of this site to attach to the chromocenter. The relative chromosome arm positions are often similar in several neighboring cells. The size of these patches of cells, assuming that they represent clones, indicates that such arrangements are at best quasi-stable: they may be maintained over at least one, but less than four, cell divisions. The observed nuclear organization in salivary glands is inconsistent with the idea that position in the polytene nucleus plays a major role in the normal genetic regulation of euchromatic loci.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Biogenesis of Catalase-Positive Rods in Excretory Duct Cells of Salivary Glands

1976 ◽  
Vol 34 ◽  
pp. 62-63
Author(s):  
Dwight K. Romanovicz ◽  
Jacob S. Hanker
Keyword(s):  
Light Microscopy ◽  
Salivary Glands ◽  
Submandibular Gland ◽  
Excretory Duct ◽  
Exocrine Glands ◽  
Duct Cells ◽  
Peroxidatic Activity ◽  
Microscopic Studies ◽  
Different Dimensions

The presence of catalase-positive rods (Fig. 1) of different dimensions, which frequently have a crystalline appearance by light microscopy, has been reported. They seem to be related to peroxisomes which were characterized morphologically and cytochemically in parotid and other exocrine glands of the rat by Hand in 1973. Our light microscopic studies of these spherical microbodies and rods of different sizes, stained by virtue of the peroxidatic activity of their catalase, indicate that they are almost entirely confined to the cells of the striated and execretory ducts of the submandibular gland in the mouse. The rods were usually noted only in the proximity of the ductal microbodies. The latter frequently showed a tendency to appear in linear close array, or even to be contiguous (Fig. 2). This suggested that the rods could be formed by the fusion of microbodies.

An adrenocortical oncocytoma with unusual mitochondrial inclusions and cytoplasmic crystals

1994 ◽  
Vol 52 ◽  
pp. 250-251
Author(s):  
W.T. Gunning ◽  
G.D. Haselhuhn ◽  
E.R. Phillips ◽  
S.H. Selman
Keyword(s):  
Adrenal Gland ◽  
Salivary Glands ◽  
Mitotic Activity ◽  
Diagnostic Criteria ◽  
Vascular Invasion ◽  
Benign Neoplasm ◽  
Benign Tumors ◽  
Nuclear Morphology ◽  
Case Presentation ◽  
Microscopic Evidence

Within the last few years, adrenal cortical tumors with features concordant with the diagnostic criteria attributed to oncocytomas have been reported. To date, only nine reported cases exist in the literature. This report is the tenth case presentation of a presumptively benign neoplasm of the adrenal gland with a rare differentiation. Oncocytomas are well recognized benign tumors of the thyroid, parathyroid, and salivary glands and of the kidney. Other organs also give rise to these types of tumors, however with less frequency than the former sites. The characteristics generally used to classify a tumor as an oncocytoma include the following criteria: the tumor is 1) usually a solitary circumscribed mass with no gross nor microscopic evidence of metastasis (no tissue nor vascular invasion), 2) fairly bland in terms of mitotic activity and nuclear morphology, and 3) composed of large eosinophillic cells in which the cytoplasm is packed full of mitochondria (Figure 1).

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