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PubMed2005

zds1, a novel gene encoding an ortholog of Zds1 and Zds2, controls sexual differentiation, cell wall integrity and cell morphology in fission yeast.

While screening for genes that reverse the sporulation-deficient phenotype of the ras1delta diploid Schizosaccharomyces pombe strain, we identified zds1. This gene shares sequence homology with the ZDS1 and ZDS2 genes from Saccharomyces cerevisiae, which appear to be involved in multiple cellular events. Expression of Zds1 in ras1delta diploid cells elevated their sporulation rate from 0.3 to 11.2%. Expression of the Zds1 C-terminal region increased the sporulation rate further (to 21.9%) while introduction of the Zds1 N-terminal region had no effect. zds1 expression did not induce sporulation in strains with mutations in genes participating in the downstream MAP kinase cascade. The zds1-disrupted strain is sensitive to CaCl2, and this effect is suppressed by the C-terminal region of Zds1. The growth of the zds1delta strain is markedly inhibited by cold temperatures, while its viability decreased in the stationary phase. Moreover, the zds1delta strain is round in shape and very sensitive to zymolyase, and its cell wall becomes thicker than that of wild type. Thus, zds1 must be required to maintain cell wall integrity. The Zds1-GFP fusion protein localized to the cytosol, the septum, and the cell cortex. Its localization in the septum was dependent on its C-terminal region. Overexpression of the C-terminal region of Zds1 induced multi-septa and abnormal zygotes. We propose that the C-terminal region is the functional domain of Zds1 while the N-terminal region is a negative regulatory region. Thus, Zds1 is involved in multiple cellular events in fission yeast, including sexual differentiation, Ca2+ tolerance, cell wall integrity, viability in the stationary phase, and cell morphology.

Adaptor Proteins, Signal Transducing↗

PubMed1961

Quantitative radioautographic studies on exponentially growing cultures of Escherichia coli. The distribution of parental DNA, RNA, protein, and cell wall among progeny cells.

Exponentially growing cultures of E. coli were examined by quantitative radioautographic techniques to determine the distribution of labeled DNA, RNA, protein, and cell wall among the progeny cells of successive generations. It was found that DNA is in large structures, non-randomly distributed in the progeny. About one-half of the cells have four such structures and approximately one-half contain these four structures plus four smaller ones. These structures show remarkable stability. Fewer than 3.5 per cent of the large structures break in one division time. Protein, RNA, and cell wall are all distributed randomly among progeny cells. The number of units of each component that show random segregation must be 200 or more.

Autoradiography↗

PubMed1980

Reassembly of the regularly arranged subunits in the cell wall os Lactobacillus brevis and their reattachment to cell walls.

The reassembly of tetragonally arranged subunits in the cell wall of Lactobacillus brevis and the reattachment of the subunits to cell wall fragments were investigated by electron microscopy. The subunits dissociated from the cell wall with guanidine hydrochloride (GHCl) reassembled into the same regular array as seen in native cell wall after dialysis against neutral buffer even in the absence of specific cations. The subunits could also reattach to the cell wall fragments from which they had been removed by treatment with GHCl, sodium dodecyl sulfate or cold trichloroacetic acid but not to those treated with hot formamide. Heterologous reattachment of the subunits occurred on cell wall fragments obtained from L. fermentum but not on those from L plantarum or L. casei subsp. casei. On the basis of these observations and chemical analyses of the cell wall fragments, the subunits of L. brevis appeared to be bound by hydrogen bonds to a neutral polysaccharide moiety in the cell wall but not to peptidoglycan or teichoic acid.

Cell Wall↗

PubMed1975

Immunochemical characterization of cell wall protein antigen purified from the cell wall autolysate of Clostridium botulinum type A.

The cell wall protein antigen was solubilized from the isolated cell walls of Clostridium botulinum type A by autolysis and purified by diethylaminoethyl-cellulose column chromatography followed by gel filtration on Sephadex G-150. The two fractions showed a high degree of the serological activity and produced a main fused precipitin line in immunodiffusion tests against the homologous antiserum. The fact that antigenic fractions contained various kinds of amino acids but no detectable amounts of amino sugars or carbohydrates suggests that the antigens were principally composed of proteins. The protein antigen possessed multiple antigenic components in immunoelectrophoresis. As serological activity, the antigen was heat-stable and resistant to tryptic digestion but sensitive to the actions of pronase, nagarse or pepsin. The protein antigen appeared to be responsible for the common antigenicity among the proteolytic strains of C. botulinum.

Antigens, Bacterial↗

PubMed1999

The contribution of cell wall proteins to the organization of the yeast cell wall.

Our knowledge of the yeast cell wall has increased rapidly in the past few years, allowing for the first time a description of its structure in molecular terms. Two types of cell wall proteins (CWPs) have been identified that are covalently linked to beta-glucan, namely GPI-CWPs and Pir-CWPs. Both define a characteristic supramolecular complex or structural unit. The GPI building block has the core structure GPI-CWP-->beta1,6-glucan-->beta1,3-glucan, which may become extended with one or more chitin chains. The Pir building block is less well characterized, but preliminary evidence points to the structure, Pir-CWP-->beta1,3-glucan, which probably also may become extended with one or more chitin chains. The molecular architecture of the cell wall is not fixed. The cell can make considerable adjustments to the composition and structure of its wall, for example, during the cell cycle or in response to environmental conditions such as nutrient and oxygen availability, temperature, and pH. When the cell wall is defective, dramatic changes can occur in its molecular architecture, pointing to the existence of cell wall repair mechanisms that compensate for cell damage. Finally, evidence is emerging that at least to a considerable extent the cell wall of Saccharomyces cerevisiae is representative for the cell wall of the Ascomycetes.

Cell Cycle↗

PubMed1977

Comparison of Coccidioides immitis arthrospore, mycelium, and spherule cell walls, and influence of growth medium on mycelial cell wall composition.

Comparative lipid content, cell wall yield, neutral monosaccharide, glucosamine, and protein (amino acid) contents of arthrospores, mycelia, and spherules of Coccidioides immitis Cash were studied. Cellular lipid contents were found in the decreasing order: spherules, arthrospores, mycelia. Lipid content of mycelia did not reach the level of arthrospores or spherules even when mycelia were grown on relatively rich media. Cell wall yields of spherules were lower than for mycelia when grown on comparable media. Cell walls of arthrospores, mycelia, spherules, and spherule culture filtrate all contained 3-O-methylmannose, mannose, and glucose, but in varying amounts. Cell wall yield and cell wall glucose content increased in mycelia grown in increasingly rich media, whereas mannose content either decreased or remained constant.

Acetylglucosamine↗

PubMed2005

Telavancin, a multifunctional lipoglycopeptide, disrupts both cell wall synthesis and cell membrane integrity in methicillin-resistant Staphylococcus aureus.

The emergence and spread of multidrug-resistant gram-positive bacteria represent a serious clinical problem. Telavancin is a novel lipoglycopeptide antibiotic that possesses rapid in vitro bactericidal activity against a broad spectrum of clinically relevant gram-positive pathogens. Here we demonstrate that telavancin's antibacterial activity derives from at least two mechanisms. As observed with vancomycin, telavancin inhibited late-stage peptidoglycan biosynthesis in a substrate-dependent fashion and bound the cell wall, as it did the lipid II surrogate tripeptide N,N'-diacetyl-L-lysinyl-D-alanyl-D-alanine, with high affinity. Telavancin also perturbed bacterial cell membrane potential and permeability. In methicillin-resistant Staphylococcus aureus, telavancin caused rapid, concentration-dependent depolarization of the plasma membrane, increases in permeability, and leakage of cellular ATP and K(+). The timing of these changes correlated with rapid , concentration-dependent loss of bacterial viability, suggesting that the early bactericidal activity of telavancin results from dissipation of cell membrane potential and an increase in membrane permeability. Binding and cell fractionation studies provided direct evidence for an interaction of telavancin with the bacterial cell membrane; stronger binding interactions were observed with the bacterial cell wall and cell membrane relative to vancomycin. We suggest that this multifunctional mechanism of action confers advantageous antibacterial properties.

Aminoglycosides↗

PubMed1997

Characterization of a 200-kDa diatom protein that is specifically associated with a silica-based substructure of the cell wall.

The cell wall of a diatom is made up of a silica-based scaffold and organic macromolecules. Proteins located in the cell wall are believed to control morphogenesis of the species-specific silica structures of the scaffold. However, data that correlate distinct silica elements and specific proteins within the diatom cell wall have not been reported. Here, the cell wall protein HEP200 (200-kDa HF-extractable protein) from the diatom Cylinidrotheca fusiformis is identified and characterized. HEP200 is tightly associated with a substructure of the silica scaffold. It is a member of a new protein family, of which two more members are identified. Each member displays the same bipartite structure. The N-terminal part consists of a variable number of a repeated sequence motif (PSCD domain), whereas the C-terminal part is unique. Immunolocalization experiments revealed the arrangement of different proteins within the cell wall. Frustulins, a previously described group of glycoproteins, constitute the outer coat of the cell wall and exhibit a ubiquitous distribution. In contrast, HEP200 is specifically located at a subset of about six silica strips in intact cell walls, shielded by frustulins. This study therefore identifies a diatom cell wall protein (HEP200) that is associated with a distinct substructure of the silica scaffold.

Algal Proteins↗

PubMed1996

Cell-Wall Changes and Cell Tension in Response to Cold Acclimation and Exogenous Abscisic Acid in Leaves and Cell Cultures.

Freeze-induced cell tensions were determined by cell water relations in leaves of broadleaf evergreen species and cell cultures of grapes (Vitis spp.) and apple (Malus domestica). Cell tensions increased in response to cold acclimation in leaves of broadleaf evergreen species during extracellular freezing, indicating a higher resistance to cell volume changes during freezing in cold-hardened leaves than in unhardened leaves. Unhardened leaves, typically, did not develop tension greater than 3.67 MPa, whereas cold-hardened leaves attained tensions up to 12 MPa. With further freezing there was a rapid decline and a loss of tension in unhardened leaves of all the broadleaf evergreen species studied. Also, similar results were observed in cold-hardened leaves of all of the species except in those of inkberry (Ilex glabra) and Euonymus fortunei, in which negative pressures persisted below -40[deg]C. Abscisic acid treatment of inkberry and Euonymus kiautschovica resulted in increases in freeze-induced tensions in leaves, suggesting that both cold acclimation and abscisic acid have similar effects on freezing behavior[mdash] specifically on the ability of cell walls to undergo deformation. Decreases in peak tensions were generally associated with lethal freezing injury and may suggest cavitation of cellular water. However, in suspension-cultured cells of grapes and apple, no cell tension was observed during freezing. Cold acclimation of these cells resulted in an increase in the cell-wall strength and a decrease in the limiting cell-wall pore size from 35 to 22 A in grape cells and from 29 to 22 A in apple cells.

Journal Article↗

PubMed2005

The structure of secondary cell wall polymers: how Gram-positive bacteria stick their cell walls together.

The cell wall of Gram-positive bacteria has been a subject of detailed chemical study over the past five decades. Outside the cytoplasmic membrane of these organisms the fundamental polymer is peptidoglycan (PG), which is responsible for the maintenance of cell shape and osmotic stability. In addition, typical essential cell wall polymers such as teichoic or teichuronic acids are linked to some of the peptidoglycan chains. In this review these compounds are considered as 'classical' cell wall polymers. In the course of recent investigations of bacterial cell surface layers (S-layers) a different class of 'non-classical' secondary cell wall polymers (SCWPs) has been identified, which is involved in anchoring of S-layers to the bacterial cell surface. Comparative analyses have shown considerable differences in chemical composition, overall structure and charge behaviour of these SCWPs. This review discusses the progress that has been made in understanding the structural principles of SCWPs, which may have useful applications in S-layer-based 'supramolecular construction kits' in nanobiotechnology.

Bacillaceae↗

PubMed1983

Cell wall assembly of Neurospora crassa: lack of evidence for preexisting cell wall acting as primer or template.

Cell wall formation of Neurospora crassa and other filamentous fungi involves the apical extension of preexisting cell wall in a complex assembly sequence; however, it is not known if preexisting wall participates in the formation of new cell wall. It was found that temperature-sensitive protoplasts which lack detectable preexisting wall form cell wall upon a shift to a permissive temperature. Similarly, temperature-sensitive colonial mutants form morphologically normal cell wall directly from preexisting abnormal hyphae after a shift to a permissive temperature. These results are consistent with the idea that cell wall assembly occurs without the participation of preexisting cell wall as either primer or template for new cell wall assembly.

Cell Wall↗

PubMed1981

Characterization of Carrot Cell Wall Protein : II. IMMUNOLOGICAL STUDY OF CELL WALL PROTEIN.

Antiserum was raised against a synthetic nona-peptide which was predicted to have considerable homology with the unhydroxylated, unglycosylated precursor of cell wall proteins from several plants. The antiserum is able to recognize the major cell wall protein of incubated carrot (Daucus carota) root discs which is produced when the discs are treated with a proline hydroxylase inhibitor and then labeled with radioactive proline. This technique has potential applications in studying cell wall biosynthesis and its regulatory control mechanisms.

Journal Article↗

PubMed1980

Structure of Plant Cell Walls: XI. GLUCURONOARABINOXYLAN, A SECOND HEMICELLULOSE IN THE PRIMARY CELL WALLS OF SUSPENSION-CULTURED SYCAMORE CELLS.

The isolation, purification, and partial characterization of a glucuronoarabinoxylan, a previously unobserved component of the primary cell walls of dicotyledonous plants, are described. The glucuronoarabinoxylan constitutes approximately 5% of the primary walls of suspension-cultured sycamore cells. This glucuronoarabinoxylan possesses many of the structural characteristics of analogous polysaccharides that have been isolated from the primary and secondary cell walls of monocots as well as from the secondary cell walls of dicots. The glucuronoarabinoxylan of primary dicot cell walls has a linear beta-1,4-linked d-xylopyranosyl backbone with both neutral and acidic sidechains attached at intervals along its length. The acidic sidechains are terminated with glucuronosyl or 4-O-methyl glucuronosyl residues, whereas the neutral sidechains are composed of arabinosyl and/or xylosyl residues.

Journal Article↗

PubMed1962

Studies on the chemical structure of the streptococcal cell wall. II. The composition of group C cell walls and chemical basis for serologic specificity of the carbohydrate moiety.

The trypsinized cell walls of Group C streptococci contain two components, the group-specific carbohydrate and a mucopeptide polymer. Hot formamide extraction of Group C cell walls results in a soluble group-specific carbohydrate fraction and an insoluble mucopeptide residue. This mucopeptide, similar in composition to that of Groups A and A-variant streptococci, contains N-acetylglucosamine, N-acetylmuramic acid, alanine, glutamic acid, lysine, and glycine. It is dissolved by the muralytic enzymes, including lysozyme, which does not attack the whole cell wall. Lysis of the cell wall by phage-associated lysin results in the release of soluble fragments composed of the elements of mucopeptide. Group C carbohydrate extracted with formamide is composed primarily of N-acetylgalactosamine and rhamnose. Serological studies suggest that the specificity of Group C carbohydrate is determined by the N-acetylgalactosamine.

Carbohydrates↗

PubMed1965

STUDIES OF STREPTOCOCCAL CELL WALLS. VII. CARBOHYDRATE COMPOSITION OF GROUP B CELL WALLS.

Wittner, Masako K. (Presbyterian-St. Luke's Hospital, Chicago, Ill.), and James A. Hayashi. Studies of streptococcal cell walls. VII. Carbohydrate composition of group B cell walls. J. Bacteriol. 89:398-402. 1965.-Group B streptococcal cell walls contain 63% protein, 10% rhamnose, 18% hexose (mainly galactose, but also some glucose), 7% hexosamine (mainly glucosamine, but also galactosamine), and 3% muramic acid. The group and type antigens were extracted from isolated cell walls by acid treatment and enzymatic hydrolysis, and fractionated either with ethanol or on a diethylaminoethyl-cellulose column. Serological and chemical analyses of the fractions obtained in the two fractionation methods show that the group antigen is a rhamnose-rich polysaccharide and that the type antigen is rich in galactose and contains hexosamines.

Antigens↗

PubMed1989

Streptococcal cell wall arthritis. Passive transfer of disease with a T cell line and crossreactivity of streptococcal cell wall antigens with Mycobacterium tuberculosis.

Primary lymph node cells derived from streptococcal cell wall arthritic rats or those derived from adjuvant arthritic rats proliferated in response to cell wall antigens derived from either streptococcal cell walls or those from M. tuberculosis. In addition, two T cell lines have been isolated from lymph nodes of rats during the chronic phase of streptococcal cell wall arthritis. These T cell lines transfered clinical disease to naive syngeneic irradiated recipients, and they proliferated in the presence of cell wall antigens derived from streptococci or antigens derived from Mycobacterium but failed to proliferate in the presence of the 65-kD antigen (containing the sequence TFGLQLELT) derived from Mycobacterium. These observations indicate that T cells play a crucial role in the pathogenesis of streptococcal cell wall arthritis and suggest that antigenic crossreactivity exists between cell walls of group A streptococci and antigens derived from Mycobacterium. The 65-kD Mycobacterium protein is not involved in the observed antigenic crossreactivity.

Animals↗

PubMed1985

Reassembly of a regularly arranged protein in the cell wall of Lactobacillus buchneri and its reattachment to cell walls: chemical modification studies.

Regularly arranged protein (RA protein) isolated from the cell wall of Lactobacillus buchneri was chemically modified by amidination, acetylation, succinylation, and amidation. The modified RA proteins were examined for their ability to reassemble into a regular array and to reattach to the cell walls from which the regular array had been detached. Only amidinated RA protein could be either reassembled into a regular array or reattached to the cell walls; RA proteins modified by the other methods lost the ability for both reassembly and reattachment. The unmodified RA protein could be reattached to periodate-oxidized cell walls, but not to methylated ones. These results suggest that the positive charge of the amino group as well as the negative charge of the carboxyl group of RA protein plays an important role(s) in morphogenesis of the hexagonal array and in its attachment to the underlying cell wall layer. The periodate-insensitive lone hydroxyl groups of the neutral polysaccharide molecule in the cell wall seem to be the receptor sites for RA protein in the attachment to the cell wall.

Bacterial Proteins↗

PubMed1980

Bacteriophage T4D receptor and the Escherichia coli cell wall structure: binding of endotoxin-like particles to the cell wall.

A variety of degradative treatments have been used to investigate the nature of the structure and components of the cell walls of Escherichia coli B. The binding and localization of the endotoxin-like particles found on the cell walls were of special interest because some of them are associated with the site where the inner tail tube of bacteriophage T4D penetrates the cell wall. Modified cell walls were obtained by heating a suspension of bacterial cells originally in 0.1 M phosphate, pH 7.0, after the addition of 12.5 M NaOH to a final concentration of 0.25 M. With regard to the endotoxin-like particles, it was found that: (i) at least part of them still remained bound to the modified cell wall after the alkali treatment; (ii) the subsequent incubation of alkali-treated cell walls with lysozyme destroyed the bacterial form and released a complex of endotoxin-like particles together with a fibrous material; (iii) on the other hand, treatment with 45% phenol at 70 degrees C removed the endotoxin-like particles from the surface of the alkali-treated cell walls, but most of the fibrous material was left on the cell wall; and (iv) incubation of alkali-treated cell walls with 5 mM ethylenediaminetetraacetic acid at 20 degrees C also removed the endotoxin-like particles, but did not disrupt the rodlike bacterial form. However, if the ethylenediaminetetraacetic acid treatment was performed at 55 degrees C, the bacterium-like form was destroyed. These differential sensitivities to ethylenediaminetetraacetic acid suggested that loosely bound divalent metal ions normally hold these endotoxin-like particles on the cell wall surface, but that probably more tightly bound metal ions are involved in the determination of cell shape. Analysis of the protein components of the alkalitreated cell walls showed that only one protein was present in significant amounts, and this protein had an electrophoretic mobility similar to that of the Braun lipoprotein. This protein was released from the alkali-treated cell walls upon heating with 2% sodium dodecyl sulfate at 100 degrees C. Phospholipids were also absent from this structure. The distribution of the remaining cell wall components on the alkali-treated cell walls is discussed.

Bacterial Proteins↗