Cell wall and membrane

Bateman D. F. Basham H G. (1976). Degradation of plant cell walls and membranes by microbial enzymes. In Heitefuss R. Williams P. H., ed. Encyclopedia of Plant Physiology, Vol. 4. New York Springer-Verlag, 316-355. 

As shown in Fig. 1 biosorption comprises a variety of processes including ion exchange, chelation, adsorption, and diffusion through cell walls and membranes all of which are dependent on the species used, the biomass origin and, and solution chemistry (Gavrilescu 2004). Biosorption is a fast and reversible process for removing toxic metal ions from solution. 

Baddiley, J. (1989). Bacterial cell walls and membranes. Discovery of the teichoic acids, Bioessays, 10, 207-210. 

Molecular Composition of Bacterial Cell Walls and Membranes... 

Another major component of the cell membranes are the lipopolysaccharides, which are present as phospholipid bilayers. Following the death of bacteria, the biopolymers that constitute their cell walls and membranes become part of the detrital organic carbon pool. The great abundance of these biopolymers in seawater and the sediments is a reflection of their resistance to chemical degradation and the important role that bacterioplankton play in marine biomass production. 

Rogers HJ, Perkins HR, Ward JB, Microbial cell walls and membranes. Chapman and Hall, New York, NY, 1980. 

To use organic molecules as a food source, microorganisms have to be able to take up the substance and metabolize it within their cells. A prerequisite is that the molecules are water-soluble and that they are small enough to pass through the cell walls and membranes of the microorganism. Polymers are typically not water-soluble and, by definition, are not small molecules [4]. Therefore, the biodegradation of polymers typically needs to follow four distinct steps. 

Figure 6. A Photomicrograph (x 51,000) of caffeine treated leaf epidermal cell showing electron-dense deposits on cell wall and membrane vesicles fusing with the plasmalemma (arrows). B Immunofluorescence labeling of flavonoids in cell walls of leaf epidermal strips (arrows) and autofluorescent stomata (x 62.5). C Immunogold labeling of the walls of a mesophyll cell (left, x 41,000). Ch, chloroplast EC, epidermal cell G, Golgi IS, intercellular space MC, mesophyll cell (right, control x 19,500).

Phenolic compounds disrupt cell walls and membranes, precipitate proteins, and inactivate enzymes. They are bactericidal (including mycobacteria) and fungicidal and they are capable of inactivating lipophilic viruses. They are not sporicidal. Dilution and time of exposure recommendations of the manufacturer must be followed. 

H. J. Rogers and H. R. Perkins, Cell Walls and Membranes, Spon, London, 1968. 

Fig. 4.9 Illustration of the gram positive cell wall and membrane...

Enzymes are found embedded in cell walls and membranes as well as occuring in the various fluids found in living organisms. A number of enzymes are produced in specific areas of the body by the metabolism of inactive protein precursors known as proenzymes or zymogens. 

Mycobacterium tuberculosis, Mycobacterium leprae Pathogens Label-free Cell wall and membrane subproteomes (193-195)... 

Agrobacterium A soil bacterium that can transfer its own genes across the plant cell wall and membrane into the nucleus. The bacterium s DNA integrates into the plant s genome. The use of Agrobacterium allows the introduction of genes from any species to be engineered into crops. 

Fig. 1.8 Schematic drawing of the cell wall and membrane of Gram-negative bacteria.

As discussed earlier, there are a number of ways by which an antibiotic can selectively interfere with biochemical processes in a microbe. This part of the chapter deals in more detail with the respective mechanisms. These include the cell wall and membrane, nucleic acid and protein synthesis, and intermediary metabolism. 

During digestion, the proteins present in food are too large to pass directly through cell walls and membranes so they are broken down into the more simple amino acid units (by enzyme hydrolysis). These small amino acids are absorbed by the villi of... 

Although seeds are the common source of lectin activity, there are reports (some contradictory) of agglutinins occurring in leaves, stems, and roots.77,94 For example, black-locust (Robinia pseudoaccacia) lectin160 was isolated from its bark, potato (Solanum tuberosum) lectin161 from its tubers, and poke-weed (Phytolacca americanum) mitogen162 from its roots. A new class of plant cell-wall and membrane-bound lectins ( /3-lectins ) has been described.116,163,164 A treatise collected several schemes for the purification of lectins.165,1658... 

We next indicate how cell wall and membrane properties influence the kinetics of reversible swelling or shrinking of plant cells. When the water potential outside a cell or group of cells is changed, water movement will be induced. A useful expression describing the time constant for the resulting volume change is... 

Rogers, H.J., Perkins, H.R. and Ward, J.B. (1980) Microbial Cell Walls and Membranes. Chapman Hall, New York. 

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