Bacteria carbohydrate metabolism

Aldol reactions occur in many biological pathways, but are particularly important in carbohydrate metabolism, where enzymes called aldolases catalyze the addition of a ketone enolate ion to an aldehvde. Aldolases occur in all organisms and are of two types. Type 1 aldolases occur primarily in animals and higher plants type II aldolases occur primarily in fungi and bacteria. Both types catalyze the same kind of reaction, but type 1 aldolases operate place through an enamine, while type II aldolases require a metal ion (usually 7n2+) as Lewis acid and operate through an enolate ion. 

The main product of anaerobic degradation of sugars by these organisms is lactic acid. Other products of bacterial carbohydrate metabolism include extracellular dextrans (see p. 40)—insoluble polymers of glucose that help bacteria to protect themselves from their environment. Bacteria and dextrans are components of dental plaque, which forms on inadequately cleaned teeth. When Ca salts and other minerals are deposited in plaque as well, tartar is formed. 

Natural feedstocks must serve many human purposes. Carbohydrates are valuable raw materials due to their actual or potential value. For example, protein plants are already utilizing rapidly reproducing reengineered bacteria that metabolize cellulose wastes converting it to more protein-rich bacteria that are harvested and then used as a protein source feed-meal for animals. Further, natural materials can be used in applications now largely reserved only for synthetic polymers. Sufficient natural materials are available for the supply of both food and polymer needs. 

Bactericidal drug for both gram positive and negative bacteria. Acts by inhibiting enzymes necessary for carbohydrate metabolism in bacteria. It is available as ointment. Used for the topical treatment of superficial wounds and skin infections. FURACIN 0.2% ointment/cream. 

Act by inhibiting enzymes necessary for carbohydrate metabolism in bacteria. 

Kandler, O. (1983). Carbohydrate metabolism in lactic acid bacteria. Anton. Leeuw, 49, 209-224. 

Insulin is a complex protein molecule produced by the pancreas in all vertebrates. This hormone regulates carbohydrate metabolism. Inability to produce insulin results in diabetes mellitus. Diabetes is treated by injections of insulin. Given the law of definite proportion, would you expect any differences in chemical activity between human insulin extracted from pancreatic tissue and human insulin produced by genetically engineered bacteria Why or why not ... 

Anaerobic bacteria can metabolize hydrocarbon material to CAA and hydrogen gas (42). Additionally, methanogenic and sulfate-reducing bacteria produce CAA from carbohydrates, amino acids and higher CAA (42). CAA are common metabolic products in the biosphere (47). but the balance between their production and destruction by microbial processes is such that the concentrations observed in formation waters are not likely to occur by these processes (2). 

Other approaches to the prevention of traveler s diarrhea are the use of lactobacillus preparations or bismuth subsalicylate. Lactobacilli are bacteria that metabolize dietary carbohydrate to lactic acid and other organic acids, reducing the intraluminal pH and inhibiting the growth of enteropathogens. 

Tabic 6 Common Enzyme Families in Secondary Carbohydrate Metabolism of Screptomyceces and Gram-Negative Bacteria... 

Transketolase (TK) is involved in anaerobic carbohydrate metabolisms such as the nonoxidative phase of the pentose phosphate pathway. In plants and photosynthetic bacteria, TK is involved in the Calvin-Benson cycle. TK catalyses the transfer of a 2-carbon dihydroxyethyl group from a ketose phosphate (donor substrate such as D-xylulose 5-phosphate) to the Cl position of an aldose phosphate (acceptor substrate such as o-ribose 5-phosphate) (Figure 4.3) (Schneider and Lindqvist 1998). The first product is an aldose phosphate released from the donor (such as glyceraldehyde 3-phosphate) and the second is a ketose phosphate (such as sedoheptulose 7-phosphate), in which the 2-carbon fragment is attached to the acceptor. Examples of the substrates and the products mentioned above are for the first reaction of the pentose phosphate pathway. In the second reaction of the same pathway, the acceptor is D-ery-throse 4-phosphate and the second product is o-fructose 6-phosphate. A snapshot X-ray crystallographic study revealed that an ot-carbanion/enamine a,p-dihydroxyethyl ThDP is formed as a key intermediate (Fiedler et al. 2002). Then, a nucleophilic attack of the a-carbanion intermediate on the acceptor substrate occurs. 

Many studies that characterized carbohydrate fermentation patterns applied methods that focused on utilization of single carbohydrates (Davis etal., 1988 Edwards and Jensen, 1992 Edwards etal., 1993 1998a 2000). It is therefore possible that these bacteria can metabolize glycerol to acrolein if other sugars or lactic acid are present. NADH produced as a byproduct of carbohydrate (or lactate) utilization is speculated to be reoxidized to NAD from the reduction of 3-HPA to 1,3-propandiol (Schiitz... 

Except for a few bacteria in which AMC is the end product of carbohydrate metabolism, AMC formation seems to be an insignificant reaction in most organisms. It has been discussed in detail because the studies on the... 

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