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PubMed1977

Changes in biochemical composition of the cell wall of the cotton fiber during development.

The composition of the cell wall of the cotton fiber (Gossypium hirsutum L. Acala SJ-1) has been studied from the early stages of elongation (5 days postanthesis) through the period of secondary wall formation, using cell walls derived both from fibers developing on the plant and from fibers obtained from excised, cultured ovules. The cell wall of the elongating cotton fiber was shown to be a dynamic structure. Expressed as a weight per cent of the total cell wall, cellulose, neutral sugars (rhamnose, fucose, arabinose, mannose, galactose, and noncellulosic glucose), uronic acids, and total protein undergo marked changes in content during the elongation period. As a way of analyzing absolute changes in the walls with time, data have also been expressed as grams component per millimeter of fiber length. Expressed in this way for plant-grown fibers, the data show that the thickness of the cell wall is relatively constant until about 12 days postanthesis; after this time it markedly increases until secondary wall cellulose deposition is completed. Between 12 and 16 days postanthesis increases in all components contribute to total wall increase per millimeter fiber length. The deposition of secondary wall cellulose begins at about 16 days postanthesis (at least 5 days prior to the cessation of elongation) and continues until about 32 days postanthesis. At the time of the onset of secondary wall cellulose deposition, a sharp decline in protein and uronic acid content occurs. The content of some of the individual neutral sugars changes during development, the most prominent change being a large increase in noncellulosic glucose which occurs just prior to the onset of secondary wall cellulose deposition. Methylation analyses indicate that this glucose, at least in part, is 3-linked. In contrast to the neutral sugars, no significant changes in cell wall amino acid composition are observed during fiber development.Compositional analyses of cell walls derived from culture-grown fibers indicate that these walls are remarkably similar to those derived from fibers grown on the plant, both in terms of composition and in terms of relative changes in composition during development.A comparison of our results on total cell wall composition and linkages of sugars as determined by a preliminary methylation analysis of unfractionated fiber walls indicates that the primary cell wall of cotton fibers is similar to that of primary cell walls of other dicotyledons and of gymnosperms as reported in the literature.

Journal Article↗
PubMed2006

Brittle stalk 2 encodes a putative glycosylphosphatidylinositol-anchored protein that affects mechanical strength of maize tissues by altering the composition and structure of secondary cell walls.

A spontaneous maize mutant, brittle stalk-2 (bk2-ref), exhibits dramatically reduced tissue mechanical strength. Reduction in mechanical strength in the stalk tissue was highly correlated with a reduction in the amount of cellulose and an uneven deposition of secondary cell wall material in the subepidermal and perivascular sclerenchyma fibers. Cell wall accounted for two-thirds of the observed reduction in dry matter content per unit length of the mutant stalk in comparison to the wildtype stalk. Although the cell wall composition was significantly altered in the mutant in comparison to the wildtype stalks, no compensation by lignin and cell wall matrix for reduced cellulose amount was observed. We demonstrate that Bk2 encodes a Cobra-like protein that is homologous to the rice Bc1 protein. In the bk2-ref gene, a 1 kb transposon-like element is inserted in the beginning of the second exon, disrupting the open reading frame. The Bk2 gene was expressed in the stalk, husk, root, and leaf tissues, but not in the embryo, endosperm, pollen, silk, or other tissues with comparatively few or no secondary cell wall containing cells. The highest expression was in the isolated vascular bundles. In agreement with its role in secondary wall formation, the expression pattern of the Bk2 gene was very similar to that of the ZmCesA10, ZmCesA11, and ZmCesA12 genes, which are known to be involved in secondary wall formation. We have isolated an independent Mutator-tagged allele of bk2, referred to as bk2-Mu7, the phenotype of which is similar to that of the spontaneous mutant. Our results demonstrate that mutations in the Bk2 gene affect stalk strength in maize by interfering with the deposition of cellulose in the secondary cell wall in fiber cells.

Biomechanical Phenomena↗
PubMed1984

[Composition of cell walls of 2 mutant strains of Streptomyces chrysomallus].

The cell walls and peptidoglycans of two mutant strains, Streptomyces chrysomallus var. carotenoides and Streptomyces chrysomallus var. macrotetrolidi, were studied. The strains are organisms producing carotenes and antibiotics of the macrotetrolide group. By the qualitative composition of the peptidoglycans the mutants belong to Streptomyces and are similar. Their glycan portion consists of equimolar quantities of N-acetyl glucosamine and muramic acid. The peptide subunit is presented by glutamic acid, L, L-diaminopimelic acid, glycine and alanine. The molar ratio of alanine is 1.2-1.3. The mutant strains differ in the content of carbohydrates, total phosphorus and phosphorus belonging to teichoic acids. Teichoic acids of the cell walls of the both strains are of the ribitolhosphate nature. The cell walls of the mutants contain polysaccharides differing from teichoic acids and consisting of glucose, galactose, arabinose and fucose. The influence of the cell wall composition of the mutant strains on their morphology and metabolism and comparison of the data relative to the mutant strains with those relative to the starting strain are discussed.

Amino Acids↗
PubMed1984

Chemical compositions of cell walls and polysaccharide fractions of spirochetes.

Cellular polysaccharide fractions of various representative members of genera of the family Spirochaetaceae were obtained by the ammonium hydroxide extraction method. The sugar composition of the polysaccharide preparations was complex and many kinds of sugars such as rhamnose, fucose, ribose, xylose, mannose, galactose, and glucose were detected in all of the spirochetes tested. Of particular interest was the presence of 4-O-methylmannose as a constituent polysaccharide in members of the genus Leptospira. This sugar was not detected in the polysaccharides of Spirochaeta, Borrelia, and Treponema. The chemical compositions of cell wall fractions were also examined. 4-O-Methylmannose was detected in the cell wall polysaccharides of the genus Leptospira but not in cell walls prepared from the Spirochaeta, Borrelia, and Treponema. The diaminopimelic acid present in cell wall peptidoglycans of the genus Leptospira was meso-diaminopimelic acid (A2pm). The molar ratios of alanine, glutamic acid, A2pm, glycine, muramic acid, and glucosamine in leptospiral cell walls were found to be approximately 2:1:1:1:1:1. In contrast to the Leptospira, the peptidoglycans of genera Spirochaeta, Borrelia, and Treponema contained ornithine (Orn) but not A2pm. Since 4-O-methylmannose and A2pm were found in the cell wall fractions of genus Leptospira but not in Spirochaeta, Borrelia, or Treponema, it was suggested that the chemical compositions of the cell wall might become an important criterion for the chemotaxonomy of Spirochaetales.

Carbohydrates↗
PubMed1997

Analysis of forage fiber and cell walls in ruminant nutrition.

Analysis of the fiber or cell wall present in forages is of major concern in ruminant nutrition because diets often contain large amounts of forage, and the fiber fraction affects both feed intake and animal performance. Traditional extractive, gravimetric methods such as crude fiber and neutral detergent fiber recover variable amounts of the plant cell wall, but they remain popular because of their ease of use and the large feed data bases available for these methods. More intensive chemical methods utilizing chromatography and spectrometric analysis provide greater detail on cell wall composition and structure, but they have been used little in ruminant nutrition. Lignin analysis has remained problematic because no definitive reference method exists. Recently attention has focused on the measurement of lignin composition and cell wall phenolic acids; however, these methods have yet to be widely adopted in ruminant nutrition. The detergent fiber methods have been semi-automated to increase sample handling capacity. Near-infrared spectroscopy is routinely used for prediction of fiber concentration in forages and has greatly increased the ease of obtaining fiber analysis of forage samples. Widespread adoption in ruminant nutrition of the more sophisticated methods of cell wall analysis is unlikely to occur until these methods can be demonstrated to improve diet formulation and prediction of animal performance.

Animal Feed↗
PubMed2003

Influence of cultivar, cooking, and storage on cell-wall polysaccharide composition of winter squash (Cucurbita maxima).

Changes in the cell-wall polysaccharides (CWP) of the edible tissues of four winter squash cultivars during storage and after cooking were investigated. A procedure for isolating cell walls of tissues containing high levels of starch was used. The starch-free CWP were sequentially fractionated using CDTA, dilute Na(2)CO(3), and 4 M KOH. Cellulose made up 40-42% of the total CWP for three cultivars (Delica, CF 2, and CF 4) at harvest but was 35% in the softer Red Warren. The pectic polysaccharides of Delica, CF 2, and CF 4 cell walls are more branched than those from Red Warren squash. The higher proportion of uronic acid in the pectic polysaccharides of Red Warren squash correlates with its lower firmness. Cooking resulted in an increase in the water-soluble pectins and a decrease in the pectins associated with cellulose. The total CWP content of the squash cultivars remained unchanged for up to 2 months of storage and then markedly decreased between 2 and 3 months of storage. The galactose content of Delica and Red Warren cell walls remained relatively constant from harvest to 2 months of storage and then decreased markedly during 2-3 months of storage.

Carbohydrates↗
PubMed1980

Defect of in vitro digestive ability of polymorphonuclear leukocytes in paracoccidioidomycosis.

Selected functions of polymorphonuclear leukocytes were studied in patients with paracoccidioidomycosis (South American blastomycosis), in healthy control individuals, and in patients with diseases unrelated to paracoccidioidomycosis. Patients with paracoccidioidomycosis were also evaluated by standard immunological techniques. Phagocytosis and digestion of Paracoccidioides brasiliensis yeastlike cells in vitro was estimated by an original method. It was based on the appearance of phagocytosed P. brasiliensis in preparations stained by a modification of the Papanicolaou method and examined with phase-contrast optics. Interpretation of such findings was confirmed by electron microscopy. Two strains of P. brasiliensis were used. Strain 8506 was freshly isolated from a patient. Strain Pb9 was known to be nonpathogenic and to have a peculiar cell wall composition. Yeastlike cells of the Pb9 strain were digested significantly better than those of strain 8506. A higher number of leukocytes per fungus cells led to a higher proportion of digested P. brasiliensis. Leukocytes from patients with paracoccidioidomycosis phagocytosed the fungus in a normal way, but had a significant lower ability to digest it in vitro. When individual cases were analyzed, there was an excellent correlation between clinical evolution and digestive ability of polymorphonuclear leukocytes. There was good correlation between both of these and immunological parameters. Leukocytes from all groups behaved comparably in tests of general leukocyte function and in their abilities to kill and digest Candida albicans. Our results indicate that, as a group, polymorphonuclear leukocytes from patients with paracoccidioidomycosis had a significant, rather specific, defect in their in vitro digestive capacity against phagocytosed P. brasiliensis. There was also an inverse correlation between strain pathogenicity and its susceptibility to in vitro digestion by polymorphonuclear leukocytes. Our findings are concordant with and relevant to clinical reality.

Candida albicans↗
PubMedDate not supplied

[Chemical composition of the cell wall of Streptomyces chrysomallus which produces the antibiotic aurantin].

The cell wall chemical composition of Streptomyces chrysomallus producing the antibiotic aurantin was studied. The cell wall represents 11--13% of the dry cell weight and contains three major polymers, namely, peptidoglycan, ribitol teichoic acid and a polysaccharide. Each muramic acid of peptidoglycan has a peptide subunit which consists of two alanine residues, glutamic acid and diaminopimelic acid residues. Peptide chains are connected with bridges consisting of one glycine residue. The poly(ribitol phosphate) chain contains glucosyl substituents and O-acetyl groups. The main monosaccharides of the polysaccharide are glucose and galactose; mannose, fucose and galactosamine are found in minor amounts. The composition of the cell wall changes during cell development and aging: the content of teichoic acid decreases while that of the polysaccharide increases. Possible factors causing these changes are discussed.

Amino Acids↗
PubMed1967

Comparative cell wall analyses of morphological forms within the genus Actinomyces.

Comparative cell wall analyses were made of mycelial and smooth forms of Actinomyces bovis and A. israelii to determine the changes which occur in the cell wall composition concurrent with a change in morphology, and to evaluate cell wall analyses as a criterion for taxonomic identification within the genus Actinomyces. Cell walls of the spider forms of A. boyis had little or no aspartic acid and a high hexosamine concentration; cell walls of the smooth forms had a high aspartic acid content and low concentrations of hexosamine. Both forms had large amounts of glutamic acid, alanine, and lysine, as previously reported. A strain of Actinomyces, previously identified as A. naeslundii on the basis of morphology and aerobic growth characteristics, was found to have the basic cell wall composition of A. israelii. When transferred from the Actinomyces maintenance broth to a thioglycolate broth, the cells of this strain passed from a mycelial form through a transient filamentous morphology to become diphtheroidal with continued incubation. Concomitantly, the concentrations of glutamic acid relative to alanine decreased, and the hexosamine content increased. Variation in morphology within the species A. israelii and A. bovis could not be related to any mutual chemical change of their cell walls.

Actinomyces↗
PubMed1999

A rapid novel method for the extraction of RNA from wild-type and genetically modified kanamycin resistant mycobacteria.

RNA extraction from mycobacteria can be a difficult and time consuming process due to their unique mycolic acid cell wall composition and the short half life of RNA. Rapid cell wall disruption is essential to isolate intact high quality RNA. Genetically modified Mycobacteria smegmatis resistant to kanamycin demonstrate an altered cell wall composition which impairs the quality of RNA obtained from these mycobacteria. In this report we describe a method of RNA extraction using the detergent Catrimox-14 resulting in high yields of pure, undegraded RNA in less than 1 h. Yields of 25-30 microg RNA per 1x10(9) cells were consistently obtained from both wild-type and genetically modified M. smegmatis. The integrity of this RNA is demonstrated by gel electrophoresis, Northern blot and cDNA analysis.

Blotting, Northern↗
PubMed2000

Hydrophobin gene expression affects hyphal wall composition in Schizophyllum commune.

Disruption of the SC3 hydrophobin gene of Schizophyllum commune (DeltaSC3 strain) affected the composition of the cell wall. Compared to a wild-type strain the amount of mucilage (i.e., water-soluble (1-3)beta-glucan with single glucose residues attached by (1-6)beta-linkages) increased considerably, while the amount of alkali-resistant glucan (linked to chitin) decreased. Reintroduction of the SC3 gene or other hydrophobins genes expressed behind the SC3 promotor restored wild-type cell wall composition. However, addition of purified SC3 protein to the medium or growing the DeltaSC3 strain in spent medium of the wild-type strain had no effect. In young cultures of wild-type strains of S.commune, not yet expressing SC3, the amount of mucilage was also relatively high. These data show that hydrophobins not only function at hydrophilic/hydrophobic interfaces, as shown previously, but also affect wall composition.

Cell Wall↗
PubMed2005

The moonlighting protein Tsa1p is implicated in oxidative stress response and in cell wall biogenesis in Candida albicans.

Candida albicans is one of the most common fungal pathogens in humans. The cell wall is the first contact site between host and pathogen and thus is critical for colonization and infection of the host. We have identified Tsa1p, a protein that is differentially localized to the cell wall of C. albicans in hyphal cells but remains in the cytosol and nucleus in yeast-form cells. This is different from Saccharomyces cerevisiae, where the homologous protein solely has been found in the cytoplasm. We report here that TSA1 confers resistance towards oxidative stress as well as is involved in the correct composition of hyphal cell walls. However, no significant change of the cell wall composition was observed in a TSA1 deletion strain in yeast-form cells, which is in good agreement with the observation that Tsa1p is absent from the yeast-form cell wall. This indicates that Tsa1p of C. albicans might represent a moonlighting protein with specific functions correlating to its respective localization. Furthermore, the translocation of Tsa1p to the hyphal cell wall of C. albicans depends on Efg1p, suggesting a contribution of the cAMP/PKA pathway to the localization of this protein. In a strain deleted for TUP1 that filaments constitutively Tsa1p can be found in the cell wall under all conditions tested, confirming the result that Tsa1p localization to the cell wall is correlated to the morphology of C. albicans.

Candida albicans↗
PubMed2001

Mutations of the secondary cell wall.

It has not been possible to isolate a number of crucial enzymes involved in plant cell wall synthesis. Recent progress in identifying some of these steps has been overcome by the isolation of mutants defective in various aspects of cell wall synthesis and the use of these mutants to identify the corresponding genes. Secondary cell walls offer numerous advantages for genetic analysis of plant cell walls. It is possible to recover very severe mutants since the plants remain viable. In addition, although variation in secondary cell wall composition occurs between different species and between different cell types, the composition of the walls is relatively simple compared to primary cell walls. Despite these advantages, relatively few secondary cell wall mutations have been described to date. The only secondary cell wall mutations characterised to date, in which the basis of the abnormality is known, have defects in either the control of secondary cell wall deposition or secondary cell wall cellulose or lignin biosynthesis. These mutants have, however, provided essential information on secondary cell wall biosynthesis.

Arabidopsis↗
PubMed2003

Genetic dissection of trehalose biosynthesis in Corynebacterium glutamicum: inactivation of trehalose production leads to impaired growth and an altered cell wall lipid composition.

The analysis of the available Corynebacterium genome sequence data led to the proposal of the presence of all three known pathways for trehalose biosynthesis in bacteria, i.e. trehalose synthesis from UDP-glucose and glucose 6-phosphate (OtsA-OtsB pathway), from malto-oligosaccharides or alpha-1,4-glucans (TreY-TreZ pathway), or from maltose (TreS pathway). Inactivation of only one of the three pathways by chromosomal deletion did not have a severe impact on C. glutamicum growth, while the simultaneous inactivation of the OtsA-OtsB and TreY-TreZ pathway or of all three pathways resulted in the inability of the corresponding mutants to synthesize trehalose and to grow efficiently on various sugar substrates in minimal media. This growth defect was largely reversed by the addition of trehalose to the culture broth. In addition, a possible pathway for glycogen synthesis from ADP-glucose involving glycogen synthase (GlgA) was discovered. C. glutamicum was found to accumulate significant amounts of glycogen when grown under conditions of sugar excess. Insertional inactivation of the chromosomal glgA gene led to the failure of C. glutamicum cells to accumulate glycogen and to the abolition of trehalose production in a DeltaotsAB background, demonstrating that trehalose production via the TreY-TreZ pathway is dependent on a functional glycogen biosynthetic route. The trehalose-non-producing mutant with inactivated OtsA-OtsB and TreY-TreZ pathways displayed an altered cell wall lipid composition when grown in minimal broth in the absence of trehalose. Under these conditions, the mutant lacked both major trehalose-containing glycolipids, i.e. trehalose monocorynomycolate and trehalose dicorynomycolate, in its cell wall lipid fraction. The results suggest that a dramatically altered cell wall lipid bilayer of trehalose-less C. glutamicum mutants may be responsible for the observed growth deficiency of such strains in minimal medium. The results of the genetic and physiological dissection of trehalose biosynthesis in C. glutamicum reported here may be of general relevance for the whole phylogenetic group of mycolic-acid-containing coryneform bacteria.

Base Sequence↗
PubMed1976

Chemical and biochemical studies for the differentiation of coagulase-positive staphylococci.

The cell wall composition, the configuration of lactic acid produced from glucose under anaerobic conditions, the occurrence of fructose-1,6-diphosphate (FDP) activated L-lactate dehydrogenase (L-LDH), and the esterase pattern were determined from more than 80 strains of coagulase-positive staphylococci isolated from man and animal. Strains isolated from man, swine, bovines and hares form a rather homogeneous group. They exhibit a similar cell wall composition, produce predominantly D,L-lactate and have a characteristic and simple esterase pattern. Coagulase-positive staphylococci isolated from dogs, horses, minks and pigeons are quite distinct from typical Staphylococcus aureus strains. They exhibit a different cell wall composition, produce only L-lactate, possess an L-LDH which is specifically activated by FDP, and have a quite complex esterase pattern.

Acetylglucosamine↗
PubMed1967

The cell walls of Pseudomonas aeruginosa. General composition.

1. Cell walls of Pseudomonas aeruginosa were prepared and analysed. 2. Separate preparations were found to be reproducible, e.g. the phosphorus contents of all batches lay in the range 2.0-2.1%. 3. Ninhydrin-positive compounds in hydrolysates accounted for 43-46% of the cell wall and 79-87% of the nitrogen of the cell wall. Examination of the results for individual ninhydrin-positive compounds showed that 5-15% of the cell wall was murein and about 30% protein. 4. Trypsin treatment of crude cell-wall preparations preferentially liberated arginine, lysine and leucine, but it was not clear whether these arose from cell-wall or cytoplasmic proteins.

Amino Acids↗