Salivary gland chromosome preparation essay example

Some of the largest polytene chromosomes described thus far occur in larval salivary gland cells of the chironomid genus Axarus.

Salivary gland

Substrate-histochemical investigations and ultrahistochemical demonstrations of acid phosphatase in larval and prepupal salivary glands of Drosophila melanogaster. The heterogeneous family of proline-rich, human salivary glycoproteins, such as PRB1 and PRH1are salivary gland specific proteins with highest level of expression.

Elgin, in Methods in EnzymologyExamining Protein Localization on Custom P-Elements Drosophila polytene chromosomes offer the ability to monitor protein-DNA and protein-protein interactions that participate in chromatin packaging and gene expression in vivo.

Blood vessels and nerves enter the glands at the hilum and gradually branch out into the lobules. Place g weights upon the coverslip of the slides. Problems with dentures are sometimes associated with minor salivary glands if there is dry mouth present see further discussion.

If insufficient spreading is obtained, the chromosomes will look like little balls, as shown in Figure 2. Rinse larvae with water and transfer to PBS in a tissue culture dish for dissection. They are clinically relevant in dissections of facial nerve branches while exposing the different lobes, since any iatrogenic lesion will result in either loss of action or strength of muscles involved in facial expression.

Fab-7 has thus been deemed a cellular memory module. Acini[ edit ] Secretory cells are found in a group, or acinus plural, acini. In contrast, sympathetic stimulation produces either a small flow, which is rich in protein, or no flow at all. Cytological studies on fixed and squashed polytene chromosomes can also be used to monitor protein-protein interactions in vivo.

Refer it to figure 1 and figure 2.

Dissection of Larval Salivary Glands and Polytene Chromosome Preparation

Once the active or repressed state is established, the state is mitotically inherited throughout development and to some degree through meiosis. Figure 1 shows an example of such a preparation, double labeled with a marker for interband regions in green and with a dye that stains the banded regions in blue.

Expression of the reporter gene provides pigment to the Drosophila eye. These are found on most major and minor glands exception may be the sublingual gland. Microanatomy[ edit ] The gland is internally divided into lobules.

These drain into ducts situated between the lobes of the gland called interlobar ducts or secretory ducts. It is also worth noting that any delay in moving the coverslip back and forth will reduce spreading of the chromosomal arms as they become more rigid when exposed to the Lactoacetic acid solution.

This may not be the complete list of references from this article. Immediately examine the tissue under a phase contrast microscope with a 20 or 40X objective to determine whether the chromosomes are well-spread.

Nerve supply[ edit ] Salivary glands are innervated, either directly or indirectly, by the parasympathetic and sympathetic arms of the autonomic nervous system. Hence they are "polytene" rather than pachytene; I do not, however, propose to use this term; I shall refer to them as "multiple threads.

Sublingual gland The sublingual glands are a pair of major salivary glands located inferior to the tongue, anterior to the submandibular glands. They secrete a purely serous fluid that begins lipid hydrolysis.

The gland has usually a number of acini connected in a tiny lobule. In protozoans, there is no transcription, since the puff consists only of DNA.

Each acinus consists of a single layer of cuboidal epithelial cells surrounding a lumen, a central opening where the saliva is deposited after being produced by the secretory cells.

The three forms of acini are classified in terms of the type of epithelial cell present and the secretory product being produced: The polytene chromosome contains two types of bands, dark bands and interbands.

The glands are located posterior to the mandibular ramus and anterior to the mastoid process of the temporal bone.

Polytene chromosome

This methodology has been applied to the study of HP1. The puffing is caused by the uncoiling of individual chromomeres in a band. Protein synthesis in salivary glands of Drosophila melanogaster: Analysis of drosophila mRNA by in situ hybridization: Inhe observed similar spireme in a ciliated protozoan Loxophyllum meleagris.

On the other hand, if too much spreading has occurred, the chomosomes will be too thin and extended or in some cases fragmented into small pieces as shown in Figure 3. Z Zellforsch Mikrosk Anat.

In the case described earlier, it is possible to determine whether HP1 associates with known partner proteins when tethered at ectopic genomic locations. InHeitz studied different species of Drosophila D.Example of a High Quality Squash of identified on the basis of their characteristic shapes and sizes.

5 m Lab 4A. Preparation of Drosophila Polytene Chromosome Squashes A response is required for each item marked: (#__). Your grade for the lab 4 report (lab 4A and 4B chromosomes from the Drosophila larval salivary gland for his.

Chromosome puff activity and protein synthesis in larval salivary glands of Drosophila melanogaster. This article has been cited by other articles in PMC. Abstract. Secretion proteins from larval salivary glands of Drosophila melanogaster were analyzed with acrylamide gel electrophoresis.

[The puffs of salivary gland chromosomes of. Polytene chromosome.

Salivary Gland Chromosome Preparation Essay

for example, in Chironomus and are called Balbiani rings after their discoverer. Puffs are reversible modifications of polytene chromosomes; (BR) in principle are giant puffs in the polytene chromosomes of the salivary gland cells of larvae of Chironomus tentans, as first described in by Balbiani.

They are. A minor salivary gland may have a common excretory duct with another gland, or may have its own excretory duct. For example, lactoferrin in saliva binds naturally with iron. Since iron is a major component of bacterial cell walls, removal of iron breaks down the cell wall, which in turn breaks down the bacteria.

Polytene chromosome. Another example within the fly itself is the tandem duplication of various polytene bands located near the centromere of the X chromosome which results in the Bar they are also referred to as "salivary gland chromosomes". The large size of the chromosome is due to the presence of many longitudinal strands.

Essays & Papers Salivary Gland Chromosome Preparation - Paper Example Salivary Gland Chromosome Preparation Introduction: Microscopic, threadlike part of the cell and a structured DNA which carries hereditary information in the form of genes is a chromosome - Salivary Gland Chromosome Preparation introduction.

Preparation of Drosophila Polytene Chromosome Squashes for Antibody Labeling Download
Salivary gland chromosome preparation essay example
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