Animal tissues, polysaccharides from

Mixed polysaccharides from animal connective tissue. 

In a second class of regulatory enzymes the active and inactive forms are inter-converted by covalent modifications of their structures by enzymes. The classic example of this type of control is the use of glycogen phosphorylase from animal tissues to catalyse the breakdown of the polysaccharide glycogen yielding glucose-1-phosphate, as illustrated in Fig. 5.37. 

Polysaccharides, proteins, and lipids are involved in different structures of the plant and animal tissues used for food. The structures built from these materials are responsible for the form and tensile strength of the tissues and create the necessary conditions for the metabolic processes to occur. Compartmentation resulting from these structures plays a crucial biological role in the organisms. Some other saccharides, proteins, and lipids are stored for reserve purposes. Other constituents are either bound to different cell structures or distributed in soluble form in the tissue fluids. 

Basic Structures of Some Polysaccharides from Animal and Seaweed Tissues Variations on a General Structure [A — (1 — 3) — B — (1 — 4) —] ... 

In animal tissnes, intercellnlar lipoprotein membranes separate two cells of the same tissue, and other membranes separate intracellnlar particles from the cytoplasm. In plant tissues, cell walls are constructed from polysaccharides, but lipoprotein membranes protect intracellnlar particles in the same way as in animal tissues. Every membrane contains orifices enabling passage of hydrophilic material or gases through the membrane becanse snch transport is necessary for the metabolism. 

Cells adhere to surfaces when attractive forces exist between the cell stuf ace and the substrate of interest. In vivo, cells in animal tissues adhere to the extraceUular matrix, by binding of adhesion receptors in the ceU s membrane to the proteins of the extracellular matrix. Extracellular matrix is an interdigitating network of proteins and polysaccharides secreted by the cells themselves. For successful cultivation of anchorage dependent cells in a microfluidic device, it is necessary to provide means for the cells to attach to the device surface. Some surfaces, such as glass or poly (methyl methacrylate) (PMMA), may be naturally adhesive to certain cell types. It is generally accepted that the natural adhesiveness of these materials comes from their ability to support adsorption of semm proteins added to the culture... 

Mucopolysaccharides (MPS, also called glycosaminoglycans) are ani nic biopolymers widespread in animal tissues, especially in the intercellular matrix of connective tissues. These polysaccharides arc built up from amino sugars, either D-glucosamine or D-galactosamine, together with uronic acids, either D-glucuronic acid or L-iduronic acid and may have N-acetyl, 0- or N-sulfate groups. 

A number of conjugated deoxyribonucleoside diphosphates are known, although those knoum are less numerous than similar compounds of the ribose series. For example, dCDP-choline and dCDP-ethanolamine have been found in sea urchin eggs and in animal tissues, but their significance is unknown. Various thymidine diphosphate sugars (see Table l-I) have been isolated from bacterial cells these compounds ser e as coenzymes in the synthesis of polysaccharides in Salmonella typhimurium. 

Hyaluronic acid was first isolated by Karl Meyer from vitreous humor (30) and later from umbilical cord, synovial fluid, skin, cock s comb, certain fowl tumors, groups A and C hemolytic streptococci, and other sources 31). Historically, it has been a major and frequent if not universal component of Levene s so-called mucoitin sulfates. The polysaccharide acts in animal tissue presumably as an integral part of the gel-like ground substance of connective tissue (and other tissues). Another important function of hyaluronic acid in animals is serving as a lubricant and shock ab-sorbant in the joints. 

After extraction, hyaluronan must undergo purification as the next production operation. The extract from the animal tissue usually contains the following impurities proteins, peptides, lipids, nucleic acids, mucopolysacchrides and low molecular weight precursors. The first purification stage involves the precipitation of HA from the primary extract using ethanol or acetone or acetic acid, or a double volume of ethanol with sodium acetate at 2 °C [4]. Sometimes the dissolution-precipitation cycles are repeated several times in order to help remove low-molecular weight compounds and lipids that are soluble in acetone and ethanol. The proteins (which are free and connected with the polysaccharides) are removed... 

A limited amount of gram-positive bacteria (Streptococcus sp. and Pasteurella sp.) are able to synthesize a polysaccharide from the upper capsule (1 mm thick) they create [31,32]. The majority of such microorganisms are pathogenic to humans and animals, but they are also able to parasite in the intercellular space of the mammal s tissue. That is why there is high demand for these microorganisms ... 

The presence of nucleic acids in HA products isn t usually evaluated nor stated in the certificate of analyses. Although the antigenicity of RNA and DNA impurities is low, due to presence of the residual proteins they may be partially responsible for total antigenicity. The material from animal tissue could contain sulfated polysaccharides as a contamination. There are methods to separate the polysaccharides that can reduce the concentration of these impurities to 0.07% based on the sulfur content [25]. In addition, the sulfated mucopolysaccharides, like hyaluronan, are natural polysaccharides of animal tissues and thus cause no inflammatory reactions. 

Mixed polysaccharides from animal connective tissue. Nonalcoholic steam distillate of parts of Hamamelis virginiana. Sodium salt of hyaluronic acid [9004-61-9]. 

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