In micro-organisms

Commercial applications for polysaccharides include their use as food additives, medicines and industrial products. Although plant polysaccharides (such as starch, agar and alginate) have been exploited commercially for many years, microbial exopolysaccharides have only become widely used over the past few decades. The diversity of polysaccharide structure is far greater in micro-organisms compared to plants and around 20 microbial polysaccharides with market potential have been described. However, microorganisms are still considered to be a rich and as yet underexploited source of exopolysaccharides. 

First, let us briefly examine the route of side chain degradation in micro-organisms. The pathway is illustrated in Figure 92. 

Nature of the Gram-positive Complex in Micro-organisms, H. Henry, M. Stacey, and E. G. Teece, Nature, 156(1945) 720. 

Vitamin Bu coenzymes, Ann. N.Y. Acad, Set. 112, 547-921 (1964). I. Chemistry, chemical synthesis and biosynthesis of corrin coenzymes II. Enzymic roles of cobinamide coenzymes III. B 12-coenzymes in micro-organisms and animals. 

J. London and M. Knight, Concentrations of nicotinamide nucleotide coenzymes in micro-organisms, J. Gen. Microbiol. 44, 241-254 (1966). 

In the treatment of cellulose pulps one essential criterion for a suitable enzyme preparation is that its cellulase activity should be as low as possible, or preferably absent completely. As even extremely low cellulase activities may ruin pulp quality, Trichoderma enzyme preparations are unlikely to be suitable for these applications. Many bacterial and fungal enzymes with low cellulase activity have been shown to be suitable for treatment of pulps 14, 15, 16,17), Regulation of the often synchronous production of cellulolytic and hemicellulolytic enzymes in micro-organisms is not well understood, and is further complicated by substrate cross-specificity of these enzymes. Enzymes with both endoglucanase and xylanase activity have been reported for bacteria 18, 19) and fungi 20, 21, 22), In addition to selection of strain and... 

Adenine aminohydrolase has been found in micro-organisms, but not in mammalian cells, and the substrate specificities of the enzymes from Azotobacter vinelandii and Candida utilis were found to be similar [55, 56], Among other purines, 2-aminoadenine, A -aminoadenine, and 6-chloropurine were found to be substrates [55]. ... 

Urease. An enzyme of the hydrolase class that catalyzes the hydrolysis of urea to COj and ammonia. It is nickel protein found in micro-organisms and plant that is frequently used in clinical assays of plasma urea concentrations. 

Organic Reactions in Micro-Organized Media—Why and How Water-Promoted Organic Reactions The design of green oxidants Water as a solvent for chemical reactions Water as a benign solvent for chemical syntheses... 

Anthraquinones are found extensively in various plant species, especially from the families Liliaceae, Polygonaceae, Rhamnaceae, Rubiaceae and Fabaceae. They are also biosynthesized in micro-organisms, e.g. Penicillium and Aspergillus species. The following structural variations within anthra-quinone aglycones are most common in nature. 

In the biochemistry of D-fucose and its derivatives, there are larger lacunae in our knowledge. The biosynthesis of D-fucose has not been examined, so that it is not yet known how this sugar is produced in the organisms that contain it (mainly plants and some micro-organisms). In plants, it occurs especially in the form of steroid glycosides, whereas, in micro-organisms, it has been particularly located in antibiotic substances. It has not been identified in animals. 

Law, B. A. 1980. Transport and utilization of proteins by bacteria. In Micro-organisms and Nitrogen Sources. J. W. Payne (Editor). John Wiley and Sons, New York, pp. 381-409. 

Lectins are carbohydrate-binding proteins that have been obtained mainly from plants,1128,138 although lectin-like proteins have also been found in micro-organisms and animals,139 including mammals.140 141 Some of the properties of the lectins, and their utility as carbohydrate-specific reagents have been reviewed.1128,138,138... 

Part of the ground which is located in the immediate environment of plant roots. It is very rich in micro-organisms and biological substances. Volume 2(6). 

Table I gives approximate figures for the /3-glucuronidase activity of nearly all known sources of the enzyme. It can be seen that the enzyme is universally distributed in mammalian tissues and body fluids. This generalization probably extends to other vertebrates, and to insects and molluscs. The occurrence of the enzyme in micro-organisms is random, and bears no relation to their pathogenicity for man. The microbial enzyme may be adaptive or constitutive, and extracellular or intracellular the enzyme in Escherichia coli is adaptive and extracellular, whilst that in...

Extensive work by Cheah (121, 122, 123, 128, 130), mainly with M. expansa, has shown that large cestodes possess a cytochrome chain which differs from the mammalian system in being branched and possessing multiple terminal oxidases (Fig. 5.11). One branch resembles the classical chain with cytochrome a3 as its terminal oxidase. The terminal oxidase of the alternative pathway, which branches at the level of rhodoquinone or vitamin K, is an o-type cytochrome. Cytochrome o is an autoxidisable b-type cytochrome which is commonly found in micro-organisms, parasitic protozoa and plants. The classical chain constitutes about 20% of the oxidase capacity in cestodes and cytochrome o is quantitatively the major oxidase. Cyanide-insensitive respiration - i.e. where oxygen uptake occurs in the presence of cyanide - is characteristic of most helminths (39). Cytochrome o binds cyanide much less strongly than cytochrome a3, and it seems reasonable, therefore, to equate cyanide-insensitive respiration with the non-classical pathway. 

The glyoxylate cycle has been demonstrated in micro-organisms, germinating seeds and also in Ascaris eggs (39). It effectively short circuits the TCA... 

Table II. Occurrence of pectic enzymes in micro-organisms (9)...

D-Mannanases have been detected in micro-organisms,243-251 plants,220 204,243,252-255 and animals.243 256-239 Microbial /3-D-mannanases... 

Small quantities of the 5-amino-4-imidazolecarboxamide nucleotide were also isolated from the culture medium of Escherichia coli grown under sulfonamide bacteriostasis.i i This substance is considered to be an intermediate in purine biosynthesis, both in micro-organisms and in mammalian cells. In sulfonamide-inhibited cells and in the purine-requiring mutant of Escherichia coli, there is a block in the conversion of 5-amino-4-imidazole-carboxamide n-ribonucleotide to inosinic acid. The accumulated nucleotide in the bacterial cell is probably attacked by phosphatases this would explain why the nucleoside is the main metabolite. 

In addition to its effect on enzymes, Ag has been found to produce changes in micro-organisms which may or may not be related. Thus, silver nitrate caused marked growth inhibition of Cryptococcus albicans, and was... 

Ethylene oxide (bp, 10.8°C) is a gaseous alkylating agent. It alkylates proteins and ribonucleic and deoxyribonucleic acid in micro-organisms. It replaces labile hydrogen with hydroxyethyl groups. Ethylene oxide is utilized as a surface sterilant. Bulk crystalline materials can occlude vegetative bacterial cells or spores with crystals. Consequently, ethylene oxide does not reach them. The final step prior to sterilization is an aseptic recrystallization step. 

---