Jaswanthvinukonda/Sandbox

 THE GOLGI COMPLEX  1) Role in secretion of protein
 * HISTORICAL PERSPECTIVE AND STAINING
 * TERMINOLOGY AND POSITION
 * ELECTRON MICROSCOPIC  STRUCTURE
 * FORMATION OF GOLGI COMPLEX
 * FUNCTIONS OF THE GOLGI COMPLEX:

2) Synthesis and secretion of polysaccharides (glycosylation)

3) Sulphation

4) Plasma membrane formation

5) Plant cell wall formation

6) Lipid packaging and secretion

7) Acrosome formation and

8) Lysosome formation

HISTORICAL PERSPECTIVE AND STAINING:

Golgi apparatus is a pleomorphic organelle  and present in nearly all types of cells.This organelle was probably first observed by  LaValette st.George and platner in 1865 in studies on spermatogenesis.Camello Golgi developed a  method to stain it and made easy to demonstrate it.Golgi had enormous interest in studying nervous system.In order to study physiology and structural morphology of neurons he developed  a  staining procedure called as black reaction (Golgi method).In this particular method ,first tissues of interest  should be fix in Potassium bichromate  and then immersed in Silver nitrate .He observed that some part of the cell gets stained.He called it as internal reticular apparatus,later it was called as Golgi apparatus

Golgi considered it as reticular ,but others considered it as canalicular.Hirschler considered it as lamellar and membranous structures as half circles and rings.Its lamellar structures are supported by Nassanov(1923),Bowen(1926) and pollister(1957).Latter it was concluded that it was a platework perforated, branched or convoluted a complex manner.

Holmgren(1902) described Golgi complex as a system of clear canals called trophospongium .But this system was proved to be endoplasmic reticulum. Perroncito(1921) found smaller units of Golgi apparatus in dividing plant cell.he called them as dictyosomes.

When epithelial tissues are subjected to prolonged impregnation with osmium, as in some of the classical staining procedures for demonstration of the Golgi apparatus,electron micrographs show a selective deposition of osmium on or in the outermost profiles on the convex side of each stack of cisternae. The shorter cisternae near the concave or maturing face of the organelle do not become sites of osmium deposition even after very long periods of postosmication.they concentrated with neutral red and stained black with osmium.it shows the functional polarity among the stalks of the cisternae.see the fig.1

Palade and claude(1949)thought that Golgi apparatus was an articraft.But later ths interpretation was discarded.Dolton(1952)had identified that Golgi apparatus was found to be filled with granular masses of reduced Osmiuim.When we stained it with histochemical method for thymine pyrophosphatase,the reaction products will be accumulated in the maturing face of the cisternae.See fig.2 (Golgi apparatus in rat epididymis)

TERMINOLOGY AND POSITION :

Perroncito called golgi apparatus as smaller chunks of cisternae  called dictyosomes.

Baker (1951,53) called them as lipochondria because of the presumed lipid content.

Baker (1959) preferred to call them as  Dolton complexes.but in 1963 he accepted them as Golgi apparatus.

Sjostrand (1956) proposed the term gamma cytomembranes but later preferred to call them as Golgi membranes. In the free cells centrioles and associated Golgi apparatus was situated in the shallow groove in the nucleus.