scholarly journals The control of synthesis of bacterial cell walls. Interaction in the synthesis of nucleotide precursors

1973 ◽  
Vol 136 (4) ◽  
pp. 871-876 ◽  
Author(s):  
Raymond G. Anderson ◽  
L. Julia Douglas ◽  
Helen Hussey ◽  
James Baddiley

Phosphoenolpyruvate–UDP-N-acetylglucosamine enolpyruvyltransferase, UDP-N-acetylglucosamine pyrophosphorylase and CDP-glycerol pyrophosphorylase activities were demonstrated in soluble extracts from Bacillus licheniformis A.T.C.C. 9945. The effect of various nucleotides, sugar nucleotides and sugar phosphates on the nucleotide pyrophosphorylases was investigated. UDP-N-acetylglucosamine pyrophosphorylase was inhibited by UDP-MurAc-pentapeptide (UDP-N-acetylmuramyl-l-alanyl-d-glutamyl- meso-diaminopimelyl-d-alanyl -d-alanine) and CDP-glycerol. CDP-glycerol pyrophosphorylase was inhibited by UDP-MurAc-pentapeptide and stimulated by UDP-N-acetylglucosamine. Interaction between a precursor of one cell-wall polymer and an enzyme involved in the synthesis of a precursor of a second polymer has therefore been demonstrated. The possible role of such interaction in the control of bacterial cell-wall synthesis is discussed. Of the other compounds investigated mono- and di-nucleotides were shown to be inhibitory, indicating that nucleotide pyrophosphorylase activities may be influenced by the energy charge of the cell.

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1778 ◽  
Author(s):  
Dariusz Stępiński ◽  
Maria Kwiatkowska ◽  
Agnieszka Wojtczak ◽  
Justyna Teresa Polit ◽  
Eva Domínguez ◽  
...  

The cuticle commonly appears as a continuous lipophilic layer located at the outer epidermal cell walls of land plants. Cutin and waxes are its main components. Two methods for cutin synthesis are considered in plants. One that is based on enzymatic biosynthesis, in which cutin synthase (CUS) is involved, is well-known and commonly accepted. The other assumes the participation of specific nanostructures, cutinsomes, which are formed in physicochemical self-assembly processes from cutin precursors without enzyme involvement. Cutinsomes are formed in ground cytoplasm or, in some species, in specific cytoplasmic domains, lipotubuloid metabolons (LMs), and are most probably translocated via microtubules toward the cuticle-covered cell wall. Cutinsomes may additionally serve as platforms transporting cuticular enzymes. Presumably, cutinsomes enrich the cuticle in branched and cross-linked esterified polyhydroxy fatty acid oligomers, while CUS1 can provide both linear chains and branching cutin oligomers. These two systems of cuticle formation seem to co-operate on the surface of aboveground organs, as well as in the embryo and seed coat epidermis. This review focuses on the role that cutinsomes play in cuticle biosynthesis in S. lycopersicum, O. umbellatum and A. thaliana, which have been studied so far; however, these nanoparticles may be commonly involved in this process in different plants.


2002 ◽  
Vol 22 (1-2) ◽  
pp. 209-222 ◽  
Author(s):  
Bénédicte Flambard

1971 ◽  
Vol 9 (3) ◽  
pp. 581-601
Author(s):  
D. G. ROBINSON ◽  
R. D. PRESTON

Naked swarmers of both Cladophora rupestris and Chaetomorpha melagonium have been examined by the freeze-etching technique. The swarmers of Cladophora, collected just after settling, reveal several layers of granules external to the plasmalemma and internal to the so-called ‘fibrous-layer’. Chaetomorpha swarmers collected just before settling show extrusion of vesicles through the plasmalemma. The structures associated with the membranes are discussed in relation to known features of these swarmers already observed by sectioning. The role of granules in the synthesis of cell wall microfibrils is strengthened though the spatial arrangement of the granules seen in this investigation does not completely fulfil the ‘ordered granule’ hypothesis. Description of, and comments on, features related to cell wall synthesis, particularly the Golgi and vacuolar systems, are given.


1991 ◽  
Vol 260 (2) ◽  
pp. G213-G219 ◽  
Author(s):  
R. A. DeLa Cadena ◽  
K. J. Laskin ◽  
R. A. Pixley ◽  
R. B. Sartor ◽  
J. H. Schwab ◽  
...  

The plasma kallikrein-kinin system is activated in Gram-negative sepsis and typhoid fever, two diseases in which bacterial products have been shown to initiate inflammation. Because a single intraperitoneal injection of bacterial cell wall peptidoglycan-polysaccharide polymers from group A steptococci (PG-APS) into a Lewis rat produces a syndrome of relapsing polyarthritis and anemia, we investigated changes in the role of the kallikrein-kinin system in this model of inflammation. Coagulation studies after injection of PG-APS revealed an immediate and persistent decrease in prekallikrein levels. High-molecular-weight kininogen levels decreased significantly during the acute phase and correlated with the severity of arthritis. Factor XI levels were decreased only during the acute phase. Antithrombin III levels remained unchanged, indicating that neither decreased hepatic synthesis nor disseminated intravascular coagulation caused the decreased plasma contact factors. Plasma T-kininogen (an acute phase protein) was significantly elevated during the chronic phase. PG-APS failed to activate the contact system in vitro. Thus the kallikrein-kinin system plays an important role in this experimental model of inflammation, suggesting that activation of this system may play a role in the pathogenesis of inflammatory bowel disease and rheumatoid arthritis in which bacterial products might be etiologically important.


2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Cheng Jin

Glycosylation is a conserved posttranslational modification that is found in all eukaryotes, which helps generate proteins with multiple functions. Our knowledge of glycosylation mainly comes from the investigation of the yeastSaccharomyces cerevisiaeand mammalian cells. However, during the last decade, glycosylation in the human pathogenic moldAspergillus fumigatushas drawn significant attention. It has been revealed that glycosylation inA. fumigatusis crucial for its growth, cell wall synthesis, and development and that the process is more complicated than that found in the budding yeastS. cerevisiae. The present paper implies that the investigation of glycosylation inA. fumigatusis not only vital for elucidating the mechanism of fungal cell wall synthesis, which will benefit the design of new antifungal therapies, but also helps to understand the role of protein glycosylation in the development of multicellular eukaryotes. This paper describes the advances in functional analysis of protein glycosylation inA. fumigatus.


1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.


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