[118] Enzymes that degrade bacterial cell walls

Ghuysen, Jean‐Marie; Tipper, Donald J.; Strominger, Jack L.

doi:10.1016/0076-6879(66)08124-2

Cited by 494 publications

(426 citation statements)

References 7 publications

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“…After digestion, samples were centrifuged for 1 min in a microcentrifuge and the carbohydrate-containing supematants were analyzed. Aliquots of the supematants were assayed for both amino sugars (chitin) and neutral sugars (13-1,3 glucan) as described by Ghuysen et al (1966) and Dubois et al (1956), respectively.…”

Section: Preparation and Analysis Of Cell Wallsmentioning

confidence: 99%

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

Chiu¹,

Xiang²,

Dawe³

et al. 1997

MBoC

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Nuclear migration is required for normal development in both higher and lower eukaryotes. In fungi this process is mediated by cytoplasmic dynein. It is believed that this motor protein is anchored to the cell membrane and moves nuclei by capturing and pulling on spindle pole body microtubules. To date, four genes have been identified and shown to be required for this process in Aspergillus nidulans. The nudA and nudG genes, respectively, encode the heavy and light chains of cytoplasmic dynein, and the nudF and nudC gene products encode proteins of 49 and 22 kDa. The precise biochemical functions of the nudF and nudC genes have not yet been identified. In this report we further investigate NUDC protein function by deleting the nudC gene. Surprisingly, although deletion of nudA and nudF affect nuclear migration, deletion of nudC profoundly affected the morphology and composition of the cell wall. Spores of the strain deleted for nudC grew spherically and lysed. The thickness of the cell wall was increased in the deletion mutant and wall polymer composition was abnormal. This phenotype could be repressed by growth on osmotically buffered medium at low temperature. Similar, but less severe, effects were also noted in a strain depleted for NUDC by down-regulation. These results suggest a possible relationship between fungal cell wall biosynthesis and nuclear migration.

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Section: Preparation and Analysis Of Cell Wallsmentioning

confidence: 99%

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

Chiu¹,

Xiang²,

Dawe³

et al. 1997

MBoC

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“…Protein contents were determined by the Lowry method, using serum albumin (Sigma) as a standard. Amino-terminal residues were detected according to Ghuysen et al (1966), using glycine (Merck) as a standard. Reducing power was quantified following Thompson & Shockman (1968), with muramic acid (Sigma) as a standard.…”

Section: Induction Of Autolysis Of Whole Cells (A) Induction By Antimentioning

confidence: 99%

Cell wall and autolytic system of Lactobacillus helveticus ATCC 12046

Lortal¹,

Rousseau

Boyaval³

et al. 1991

Journal of General Microbiology

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The cell wall of Lactobacillus helveticus was found to have a three-layered structure when thin sections of whole cells or isolated cell walls were stained by various procedures and examined by electron microscopy. The main feature of the composition of isolated cell walls was a high protein content (about 48% of the cell wall dry weight) with a predominant 52 kDa protein. Peptidoglycan and what was considered as teichoic acids accounted for 36% and 14%, respectively, of the cell wall dry weight. The 52 kDa protein was apparently unglycosylated, located in the outer layer and noncovalently bound to the inner layers. Peptidoglycan was mostly assigned to the innermost layer. The conditions leading to autolysis of whole cells or isolated cell walls were determined, as well as the specificity of the autolysin involved in cell wall degradation. IntroductionLactobacillus helveticus is an important lactic acid bacterium that is involved in cheese technology (Accolas et al., 1980;Turner et al., 1983) and that has recently become the object of interest for genetic manipulation (Chassy, 1987;Sandine, 1987;Thomas & Collins, 1988). Its autolysis with the concomitant release of cytoplasmic proteases (Ezzat et al., 1986) is an essential feature of cheese maturation (Bie & Sjostrom, 1975a, b). A better understanding of the autolytic system of L. helveticus could perhaps offer a new way for an accelerated ripening of cheese. Ohmiya & Sat0 (1970) were the first to follow the autolysis of L. helveticus in technological conditions. After adding whole cells to an aseptic rennet curd, the release of DNA was noted and autolysed cells were clearly observed by electron microscopy. More recently, we promoted the autolysis of L. helveticus by suspending whole cells in dilute buffers (Lortal et al., 1989). A clear understanding of the autolytic system of L. helveticus implies, in particular, a better knowledge of the composition and structure of its cell wall, which have so far been investigated only to a limited extent (Ikawa & Snell, 1960;Baddiley & Davison, 1961 ; Williams, 1971). The main peptidoglycan amino acids were determined (Glu, Ala, Asp, Lys) as well as their respective percentage in the D-configuration (Ikawa & Snell, 1960). Previous studies also revealed the presence of glyceroltype teichoic acids (Baddiley & Davison, 1961) and neutral sugars (glucose, galactose but no rhamnose). Wall and membrane teichoic acids of L. helveticus were shown to have antigenic properties (Knox & Wicken, 1971). It has also been suggested that the cell wall of L. helveticus ATCC 10797 was composed of two layers with the outer layer presumably containing a predominant protein (Masuda & Kawata, 1983).In the work described here, a more detailed investigation of the morphology and composition of the cell wall of L. helveticus ATCC 12046 was undertaken. Moreover, the main characteristics of the autolytic system of this strain were investigated, in particular ways of promoting lysis, the effect of external factors, and the specificity of the autolytic...

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“…Excess HCl was removed by repeated evaporations over NaOH and the residue was passed through cationic resin (Dowex 50). Glucosamine-HC1 was estimated by means of a modification of the method of Rondle & Morgan as described by Ghuysen, Tipper & Strominger (1966).…”

Section: Growth Conditions and Preparation Of Protoplastsmentioning

confidence: 99%

Biochemical Studies on Walls Synthesized by Candida utilis Protoplasts

Novaes-Ledieu¹,

Garcia-Mendoza²

1970

Journal of General Microbiology

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SUMMARYProtoplasts of Candida utilis obtained by treatment with helicase built a new wall in a liquid medium. The spherical protoplast was converted to a tubular form which later changed to an ellipsoidal yeast. Walls isolated at different stages of regeneration were analysed. Glucan (42 to 48 %), mannan (25 to 31 %) and protein (8 to 9 %) were the main constituents of walls of normal and completely regenerated ellipsoidal forms. Walls of the tubular forms differed markedly by having a high content of chitin (12 to 18 %) and of protein (20 %); mannose was present only as traces. The glucan content was similar in normal, tubular and ellipsoidal regenerating yeasts. These results demonstrate that some modifications occur in the structural polysaccharides of the yeast wall which can be correlated with morphological changes in the reversion process. The significance of glucose, mannose and acetylglucosamine polymers is discussed in relation to the biosynthesis of regenerated walls.

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[118] Enzymes that degrade bacterial cell walls

Cited by 494 publications

References 7 publications

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

Cell wall and autolytic system of Lactobacillus helveticus ATCC 12046

Biochemical Studies on Walls Synthesized by Candida utilis Protoplasts

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