Discuss about tissue culture techniques and also fixation.

[maccoll]

what and what is the method,the procedure, its importance to study and to life,and the materials used.

[adalrik]

Tissue culture is the growth of tissues and/or cells separate from the organism. This is typically facilitated via use of a liquid, semi-solid, or solid growth media, such as broth or agar. Tissue culture commonly refers to the culture of animal cells and tissues, while the more specific term plant tissue culture is used for plants.
Historical usage
In 1885 Wilhelm Roux removed a portion of the medullary plate of an embryonic chicken and maintained it in a warm saline solution for several days, establishing the basic principle of tissue culture.
In 1907 the zoologist Ross Granville Harrison demonstrated the growth of frog nerve cell processes in a medium of clotted lymph.

Modern usage
In modern usage, "tissue culture" generally refers to the growth of eukaryotic cells in vitro. It is often used interchangeably with cell culture to specifically describe the in vitro culturing of sperm donor cells.

However, "tissue culture" can also be used to refer to the culturing of tissue pieces, i.e. explant culture or whole organs, i.e. organ culture.

It is a tool for the study of animal cell biology in vitro model of cell growth to allow a highly selective environment which is easily manipulated (used to optimise cell signalling pathways).

The article is available at wikipedia.

Other articles on plant tissue culture and animal cell culture are also available.

There are various techniques used for 'Fixation".

Some of these are explained below :
Methods- FixationIntroduction
This page introduces fixation methods for preservation and analysis of cells and tissues in cell biology.
It is critical to match the method of fixation with the intended analytical technique. Some types of analysis are totally incompatible with certain fixation techniques and always consider that "artefacts" can be introduced by the fixation process.

In general the Fixation process should:

1. Preserve cell structure by prevention of tissue autodigestion (autolysis)

2. Inhibits bacterial and fungal growth (preserves)

3. Make the tissue resistant to damage during subsequent processing

Paraformaldehyde
Aldehydes fix tissue by introducing cross-links between different tissue components (proteins, nucleic acids, lipids). The degree of cross-linking produced in a tissue is also proportional to fixation time. Cross-links are generated between several reactive groups (mainly -NH2 groups) such as found in protein lysine residues.

Uses: immunochemistry, in situ hybridization, cell staining

Synonyms: paraform, polyoxymethane, polymerised formaldehyde, alacide, flo-mor, formagene

Molecular formula: (CH2O)n CAS No: 30525-89-4


Methanol
Methanol dehydrates, coagulates and precipitates cellular proteins, nucleic acids and carbohydrates.

The process involves no covalent bonding between methanol fixative and tissue components.

Can be combined with an acetone step.
Formalin
Formalin is a 37% aqueous solution of formaldehyde, which fixes by cross-linking like other aldehyde fixatives and is suitable for most histological purposes.

Neutral buffered formalin (fixation time 12-24 hours) is preferred to formol-saline (a single 10% solution of formalin in 9% aqueous NaCl) as formalin pigment is avoided. Specimens may be stored in this fluid and the solution is isotonic.

Synonyms: bvf, FA, fannoform, formalith, formalin, formalin 40, formic aldehyde, formol, fyde, hoch, karsan, lysoform, methyl aldehyde, methylene glycol, methylene oxide, methanal, morbicid, oxomethane, oxymethylene, paraform, polyoxymethylene glycols, superlysoform

Molecular formula: CH2O CAS No: 50-00-0

Detergents
Detergents are not really "fixative", but a number of different types are often used in the fixation process as a method of preserving or accessing antigenic sites that may be blocked or effected by the fixation process itself.

[aelfric]

http://userpages.umbc.edu/~jwolf/method5.htm
here is a great reference