Glucose bacterial cells

Two types of immobilization are used for immobilizing glucose isomerase. The intracellular enzyme is either immobilized within the bacterial cells to produce a whole-ceU product, or the enzyme is released from the cells, recovered, and immobilized onto an inert carrier. An example of the whole-ceU process is one in which cells are dismpted by homogenization, cross-linked with glutaraldehyde, flocculated using a cationic flocculent, and extmded (42). 

The first known 1-carboxyethyl ether of a sugar was 2-amino-3-0-[(/ )-l-carboxyethyl]-2-deoxy-D-glucose or muramic acid (37). It is a component of the polysaccharide moiety of the peptidoglycan in the bacterial cell-wall. It is partially replaced by the mamo isomer, 2-amino-3-6>-[(/ )-l-carboxy-ethyl]-2-deoxy-D-mannose, in the peptidoglycan from Micrococcus lyso-deikticus. 

The main function of the ester 34 in bacterial cells seems to be its participation in the biosynthesis of the glycopeptide cell-wall polymer. If this process is blocked, there results the accumulation of a high concentration of sugar nucleotide precursors in the cell. A number of these compounds have been isolated the simplest one is the ester of uridine 5 -pyrophosphate with N-acetylmuramic acid [2-acetamido-3-0-(D-l-carboxyethyl)-2-deoxy-D-glucose] (37), first obtained from Staphylococcus aureus cells that had been treated with penicillin7,151 or Gentian Violet.144 An intermediate in the biosynthesis of 37 was isolated and shown to be the 3 -enolpyruvate ether152,153 (38). 

The homopolysaccharides starch and glycogen are stored fuels in plant, animal, and bacterial cells. They consist of D-glucose with linkages, and all three contain some branches. 

Complementary to hydrolysis by lysozyme189, an endo-acting N-acetyl-/ -D-glucosaminidase190-192 degrades bacterial cell-wall peptidoglycan to the disaccharide N-acetyl-/J-muramoyl-( 1 - 4)-2-acetamido-2-deoxy-D-glucose. 

Bacterial cells for the laboratory studies were prepared by growing V. alginolyticus in a M9 minimal salts bacterial growth medium with 8mM glucose as the carbon and energy source (70). The standard M9 medium was modified by addition of 21 g/L of NaCl (SWM9). Water used for all studies was deionized and passed through a reverse osmosis membrane (Milli-Q). 

After removing the bacterial cells by centrifuging at 16,100g for 5 min, the clear fermentation broth was subjected to analysis for residual glucose and product concentrations. Glucose concentration was measured using a YSI model 2700 Select Biochemistry Analyzer (Yellow Springs, OH). 

These two complementary systems allow the bacterial cell to metabolize lactose in response to two stimuli. Switching on the expression of the lac operon requires both the absence of glucose and the presence of lactose. This series of switches allows complex expression patterns to be built up from simple components. For this reason, the lac system is a model for other, apparently more complex, biological control systems, such as hormone action or embryonic development. 

Examination of specific carbohydrate-protein interactions can be accomplished with C-glycosides (Scheme 1). A series of C-glucosides and C-mannosides, such as 1, were employed to study the binding differences between mannose and glucose specific lectins (9). C-Mannoside derivatives (3-5) were synthesized from C-allyl derivative 2 and used to block cell-surface lectins thereby inhibiting bacterial adhesion (JO). The primary amine of 4 was functionalized with biotin to target proteins to the bacterial cell surface. 

Fig. 1.—The Biosynthetic Pathway Involved in Synthesis in Bacterial Cell Walls. [The symbol UDP refers to the uridine 5-(dihydrogen pyrophosphate) group-, UTP to uridine 5 - triphosphoric acid and GNAo to the 2-aoetamido-2-deoxy-D-glucose moiety.]...

An additional advantage of the polyhydroxyalkanoates is that the polymers can be produced by fermentation. Certain types of bacteria produce PHAs for energy storage when they are grown in glucose solution in the absence of specific nutrients. The polymer forms as discrete granules within the bacterial cell, and it is then removed by extraction to give a white powder that can be melted and modified into a variety of different products. 

The GT-B fold family includes most prokaryotic enzymes that produce secondary metabolites, like the antibiotics streptomycin, oleandomycin (Fig. 1) and vancomycin, and important bacterial cell wall precursors. It is also predicted to contain the vitally important 0-GlcNAc transferase that modifies many nuclear and cytoplasmic proteins and influences gene transcription. The first glycosyltransferase structure reported in 1994 was for the GT-B fold enzyme, P-glucosyltransferase (BGT) from bacteriophage T4 (22). This enzyme attaches glucose to modified... 

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