Morphology cell-walls

Resistance to antimicrobial agents is of concern as it is well known that bacterial resistance to antibiotics can develop. Many bacteria already derive some nonspecific resistance to biocides through morphological features such as thek cell wall. Bacterial populations present as part of a biofilm have achieved additional resistance owkig to the more complex and thicker nature of the biofilm. A system contaminated with a biofilm population can requke several orders of magnitude more chlorine to achieve control than unassociated bacteria of the same species. A second type of resistance is attributed to chemical deactivation of the biocide. This deactivation resistance to the strong oxidising biocides probably will not occur (27). 

At r = 0.5 (Fig. 9b), the most interesting and novel morphology can be observed. This morphology can be described as follows. The P4VP cores of the microspheres form a regular structure, and a P4VP bilayer surrounds each microsphere with a honeycomb-like structure, similar to a cell wall, as the number of the microsphere surrounded by the P4VP wall ( T) was 1.08. Similar structures have been observed for ABC triblock copolymers [39]. Our honeycomb-like novel structure, however, is different from that of the ABC triblock co-... 

Pine, L. Boone, C. J. Comparative cell wall analyses of morphological forms within the genus. Actinomyces. J. Bacteriol. 1967, 94, 875-883. 

Phase contrast cell boundaries and cell walls also images fibrous subcellular components, e.g., microtubules. Produces visible differences Transmission Electron Subcellular morphology... 

Source Adapted from (i) Cell Wall Mechanics of Trecheids , M.R.E. London, Yale University, 1967, p. 169-170 (ii) A Microscopic Study of Coniferous Wood in Relation to its Strength Properties , H. Garland. Ann. Missouri Botan. Gard., 1939, 26, 1-95 (iii) Morphological Foundations of Fibre Properties , L.J. Rebenfeld, J. Polymer Sci., 1965, C9, p. 91-112). 

Figure 1. Morphology of sequential IPNs. (a) Crois-poly (ethyl acrylate)-m/er-crojs-polystyrene, showing typical cellular structure and a fine structure within the cell walls, (b) Cross-poly (ethyl acrylate)-/ /cr-cross-polystyrene-s/a/-(methyl methacrylate), showing smaller domain structure. PEA structure stained with OsO. (Reproduced from ref. 5. Copyright 1972 American Chemical Society.)...

This morphology was compared with that of the extruded LDPE, which was used to produce the foams. The main source of the differences between the morphologies of the two types of material appeared to be the geometrical arrangement of the polymer in thin cell walls and the complicated mechanical and thermal history of the polymer that comprised the cell foams of the foams. 22 refs. (European Conference on Macromolecular Physics Morphology and Properties of Crystalline Polymers, Eger, Hungary, Sept.2001)... 

A preliminary stndy on the viscoelastic behaviour of polyolefin foam sheets with different chemical (PE and PP) and cellular structure by DMA, in the low freqnency and low compression ranges, is presented. DSC and SEM are also used to determine the morphological parameters of the samples. A connection between the morphological properties (apparent degree of crystallinity), type of cellular structure, homogeneity, cell size and shape, cell wall thickness) and the viscoelastic behavionr, a basic key for the development of mechanical and insnlating applications, has been established. 9 refs. 

It is well known that the structure, distribution and properties of protolignin in cell walls vary according to cell type and morphological location. This is based upon extensive studies on topochemical properties of lignin using various methods such as ultraviolet microscopic photometry (1,2), bromination-SEM-EDXA (3) and other physical or chemical analyses of isolated tissue fractions (4). 

In addition to transpeptidases, other penicillin-binding proteins (PBPs) function as transglycosylases and carboxypeptidases. All of the PBPs are involved with assembly, maintenance, or regulation of peptidoglycan cell wall synthesis. When (3-lactam antibiotics inactivate PBPs, the consequence to the bacterium is a structurally weakened cell wall, aberrant morphological form, cell lysis, and death. 

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