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PubMed2006

Assessment of Populus wood chemistry following the introduction of a Bt toxin gene.

Unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. We compared the cell wall chemical composition of three Populus lines (Populus trichocarpa Torr. & A. Gray x Populus trichocarpa Bartr. ex Marsh., Populus trichocarpa x Populus nigra L. and Populus deltoides x Populus nigra) genetically modified to express the Cry3A or Cry3B2 protein of Bacillus thuringiensis (Bt) with the cell wall chemistry of non-transformed isogenic control lines. Three genetically modified clones, each represented by 10 independent transgenic lines, were analyzed by pyrolysis molecular beam mass spectrometry, gas chromatography/mass spectrometry and traditional wet chemical analytical methods to assess changes in cell wall composition. Based on the outcome of these techniques, there were no comprehensive differences in chemical composition between the transgenic and control lines for any of the studied clones.

Bacillus thuringiensis↗
PubMed1993

A new structural type of teichoic acid and some chemotaxonomic criteria of two species Nocardiopsis dassonvillei and Nocardiopsis antarcticus.

The cell-wall teichoic acids of Nocardiopsis dassonvillei IMRU 509T, IMRU 504 and IMRU 1250 and Nocardiopsis antarcticus VKM Ac-836T have the same unique structure that has not heretofore been found in bacteria. The polymer is built of 10 to 13 repeating units: -1snGro3-P-3-beta-D-GalNAc1-2snGro3-P-. The structure has been established by chemical analysis and with NMR spectroscopy. A study of the cell-wall monosaccharide composition, peptidoglycan, and cell phospholipids also provides evidence for the close similarity of these two species.

Actinomycetales↗
PubMed1972

A gas chromatographic method for the determination of aldose and uronic Acid constituents of plant cell wall polysaccharides.

A major problem in determining the composition of plant cell wall polysaccharides has been the lack of a suitable method for accurately determining the amounts of galacturonic and glucuronic acids in such polymers. A gas chromatographic method for aldose analysis has been extended to include uronic acids. Cell wall polysaccharides are depolymerized by acid hydrolysis followed by treatment with a mixture of fungal polysaccharide-degrading enzymes. The aldoses and uronic acids released by this treatment are then reduced with NaBH(4) to alditols and aldonic acids, respectively. The aldonic acids are separated from the alditols with Dowex-1 (acetate form) ion exchange resin, which binds the aldonic acids. The alditols, which do not bind, are washed from the resin and then acetylated with acetic anhydride to form the alditol acetate derivatives. The aldonic acids are eluted from the resin with HCl. After the resin has been removed, the HCl solution of the aldonic acids is evaporated to dryness, converting the aldonic acids to aldonolactones. The aldonolactones are reduced with NaBH(4) to the corresponding alditols, dried and acetylated. The resulting alditol acetate mixtures produced from the aldoses and those from the uronic acids are analyzed separately by gas chromatography. This technique has been used to determine the changes in composition of Red Kidney bean (Phaseolus vulgaris) hypocotyl cell walls during growth, and to compare the cell wall polysaccharide compositions of several parts of bean plants. Galacturonic acid is found to be a major component of all the cell wall polysaccharides examined.

Journal Article↗
PubMed2001

In situ localization of beta-glucans in the cell wall of Schizosaccharomyces pombe.

The chemical composition of the cell wall of Sz. pombe is known as beta-1,3-glucan, beta-1,6-glucan, alpha-1,3-glucan and alpha-galactomannan; however, the three-dimensional interactions of those macromolecules have not yet been clarified. Transmission electron microscopy reveals a three-layered structure: the outer layer is electron-dense, the adjacent layer is less dense, and the third layer bordering the cell membrane is dense. In intact cells of Sz. pombe, the high-resolution scanning electron microscope reveals a surface completely filled with alpha-galactomannan particles. To better understand the organization of the cell wall and to complement our previous studies, we set out to locate the three different types of beta-glucan by immuno-electron microscopy. Our results suggest that the less dense layer of the cell wall contains mainly beta-1,6-branched beta-1,3-glucan. Occasionally a line of gold particles can be seen, labelling fine filaments radiating from the cell membrane to the alpha-galactomannan layer, suggesting that some of the radial filaments contain beta-1,6-branched beta-1,3-glucan. beta-1,6-glucan is preferentially located underneath the alpha-galactomannan layer. Linear beta-1,3-glucan is exclusively located in the primary septum of dividing cells. beta-1,6-glucan only labels the secondary septum and does not co-localize with linear beta-1,3-glucan, while beta-1,6-branched beta-1,3-glucan is present in both septa. Linear beta-1,3-glucan is present from early stages of septum formation and persists until the septum is completely formed; then just before cell division the label disappears. From these results we suggest that linear beta-1,3-glucan is involved in septum formation and perhaps the separation of the two daughter cells. In addition, we frequently found beta-1,6-glucan label on the Golgi apparatus, on small vesicles and underneath the cell membrane. These results give fresh evidence for the hypothesis that beta-1,6-glucan is synthesized in the endoplasmic reticulum-Golgi system and exported to the cell membrane.

Cell Wall↗
PubMed2004

Agromyces ulmi sp. nov., a xylanolytic bacterium isolated from Ulmus nigra in Spain.

Two xylan-degrading bacterial strains were isolated from a decayed Ulmus nigra tree in Spain. The isolates were Gram-positive, non-motile, aerobic and formed substrate mycelium which fragmented into irregular rods. 16S rRNA gene sequence analysis indicated that the isolates form a separate branch within the genus Agromyces phylogenetic cluster, with Agromyces mediolanus DSM 20152(T) being their closest relative (97.7 and 97.6 % sequence similarity). Catalase, nitrate reduction and urease tests differentiated these strains from A. mediolanus. Cell-wall peptidoglycan composition, major menaquinone, predominant fatty acids and phospholipid pattern were typical of the genus Agromyces. The DNA G+C content determined for the type strain XIL01(T) was 72 mol%. Based on the data presented, a novel species Agromyces ulmi sp. nov. is proposed. The type strain is XIL01(T) (=LMG 21954(T)=DSM 15747(T)).

Actinomycetales↗
PubMed1979

The association of Mycobacterium flavum 301 with gram-negative bacteria: ultrastructural and biochemical evidence.

Morphological characteristics, respiratory quinones, biochemical activities, cell wall ultrastructure and DNA base composition of Mycobacterium flavum 301 were studied. On the basis of the composition of its cell wall, its respiratory quinone and ubiquinone, the organism was associated with gram-negative bacteria. The strain appears to represent a group of bacteria hitherto not described.

Base Composition↗
PubMed1969

Relative rates of lysis of staphylococcal cell walls by lytic enzymes from various bacteriophage types.

Lytic enzymes were isolated from 14 strains of phage-infected Staphylococcus aureus. Cell walls were prepared from the same uninfected strains of bacteria. Comparison of the lytic rates was made for each enzyme, with each of the cell walls as substrate. Differences in the rate of substrate utilization of the various cell wall types exceeded 10-fold. Cell walls from strains 42E, 29, and 77 were the best substrates, whereas cell walls from strains 3C, 80, and 187 were the poorest substrates. The cell wall amino acid composition is discussed as related to lytic enzyme specificity. A possible explanation of phage typing of staphylococcal cells, based on enzyme activity and cell wall composition, is presented.

Amino Acids↗
PubMedDate not supplied

[Study of PLi genes action on the cell wall structure of "Saccharomyces cerevisiae" Hansen (author's transl)].

A study of the composition of cell walls extracted from a wild strain and three mutant strains "smooth colony" of Saccharomyces cerevisiae had been done. It points out differences in the mannose/glucose ratio and in the concentration of some other components of the cell wall in the mutant strains. The immunological study of the cell wall shows that "smooth colonies" mutants and wild strains differs in their mannoproteins.

Cell Wall↗
PubMed2002

Guard cell wall: immunocytochemical detection of polysaccharide components.

The composition of guard cell walls in sugar beet leaves (Beta vulgaris L.) was studied by using histochemical staining and immunocytochemical detection of cell wall antigens. The findings were compared with those in the walls of epidermal and mesophyll cells. Probing of leaf sections with monoclonal antibodies against pectins, terminal fucosyl residues linked alpha-(1-->2) to galactose, beta-(1-->3)-glucans and arabinogalactan-proteins revealed several specific features of guard cells. Pectic epitopes recognized by JIM7 were homogeneously distributed in the wall, whereas pectins recognized by JIM5 were not found in the walls themselves, but were abundant in the cuticular layer. Large amounts of molecules bearing terminal fucose were located predominantly in ventral and lateral guard cell walls. Much smaller amounts were detected in dorsal walls of these cells, as well as in the walls of pavement and mesophyll cells. Conspicuous accumulation of these compounds was observed in the vicinity of the guard cell plasmalemma, whereas labelling was scarce in the areas of the wall adjacent to the cell surface. The presence of callose clearly marked the ventral wall between the recently formed, very young guard cells. Callose also appeared in some mature walls, where it was seen as punctate deposits that probably reflected a specific physiological state of the guard cells. Large amounts of arabinogalactan-proteins were deposited within the cuticle, and smaller amounts of these proteoglycans were also detected in other tissues of the leaf. The histochemical and immunocytochemical structure of the guard cell wall is discussed in the light of its multiple functions, most of which involve changes in cell size and shape.

Antibodies, Monoclonal↗
PubMed2003

Cell-wall alterations as an attribute of Mycobacterium tuberculosis in latent infection.

Ziehl-Neelsen (ZN) staining is the key technique for diagnosis of mycobacterial infections; however, a high percentage of patients exhibit positive signs of tuberculosis, as indicated by pathology, culture of mycobacteria, and polymerase chain-reaction analysis, and yet show negative results on ZN staining. In this report we present evidence that such ZN-negative specimens represent Mycobacterium tuberculosis bacilli in a dormant state with distinct cell-wall alterations: the classical cell-wall composition-dependent ZN staining of M. tuberculosis in lung sections gradually discontinued with persistence of infection, both in mice and in human patients; in contrast, detection of mycobacteria by cell-wall composition-independent staining using a polyclonal anti-M. bovis Bacille-Calmette-Guérin serum continued with persistence of infection. These findings have important implications for diagnosis, as well as for both chemotherapy and development of vaccine strategies.'

Animals↗
PubMed1990

[The physicochemical and biochemical characteristics of the cell walls in M+ and M- variants of Streptococcus group A type 29].

The amino acid composition of cell walls and surface proteins, isolated from virulent (M+) and avirulent (M-) streptococcal strains (group A, type 29) has been determined by the method of E. H. Beachey et al. The kinetics of the lysis and proteolysis of streptococcal cell walls with muramidase and protease obtained from Actinomyces levoris and streptolysin has been studied. The constants describing the progress rates of these processes has been determined; their values in case of both lysis and proteolysis are higher in virulent strains than in avirulent ones.

Amino Acids↗
PubMed1984

Structure and biosynthesis of teichoic acids in the cell walls of Staphylococcus xylosus DSM 20266.

The simultaneous occurrence of a N-acetylglucosaminyl poly(ribitolphosphate) (beta-GlcNAc) and a N-acetylglucosaminyl poly(glycerolphosphate) (alpha-GlcNAc) in the cell walls of Staphylococcus xylosus DSM 20266 was demonstrated by different experimental lines: (1) Fractionation of extracted cell wall teichoic acid on DEAE-cellulose, (2) investigation of the composition of cell walls in the growth cycle, (3) in vitro biosynthesis using crude membranes as the source of enzyme. The polymerization of these polymers starts from CDP-ribitol and CDP-glycerol, respectively. In the presence of UDP-N-acetylglucosamine both polymers are substituted with N-acetylglucosamine at a level and with the identical anomeric configuration found in the native cell wall teichoic acids. The in vitro biosynthesis of poly(glycerolphosphate) was unique in that it was highly stimulated by UDP-N-acetylglucosamine and to a lower extent by other UDP-activated sugars. Kinetic studies have provided evidence that this stimulation is due to an increase of Vmax while Km is unchanged. Competition experiments have indicated that poly(ribitolphosphate) and poly(glycerolphosphate) were synthesized in the in vitro system in a close spatial relationship.

Cell Fractionation↗
PubMed2002

Classification of three airborne bacteria and proposal of Hymenobacter aerophilus sp. nov.

Three aerobic, gram-negative, rod-shaped, non-spore-forming, red-pigmented, airborne bacteria (I/26-Cor1T, I/32A-Cor1 and I/74-Cor2) collected in the Museo Correr (Venice, Italy) were investigated to determine their taxonomic status by analysing their biochemical, physiological and chemotaxonomic features and the G+C content of genomic DNA and by comparing their genomic fingerprints. Additionally, the almost complete 16S rRNA gene sequence of strain I/26-Cor1T was analysed. The three strains were nearly identical in their morphological, physiological, biochemical and chemotaxonomic properties. The strains contained a menaquinone system with the predominant menaquinone MK-7 and a fatty acid profile with C15:0 anteiso, C15:0 iso and C16:1 predominant. Phosphatidylethanolamine and several unidentified lipids were detected in the polar lipid profiles. The polyamine pattern consisted of sym-homospermidine as the major compound. meso-Diaminopimelic acid was found as the characteristic cell-wall diamino acid. The DNA base composition of the three strains ranged from 60 to 63 mol% G+C. Phylogenetically, strain I/26-Cor1T was most closely related to Hymenobacter actinosclerus (95.8% 16S rRNA gene sequence similarity). Physiological and genomic characteristics indicated that the two strains I/26-Cor1T and I/32A-Cor1 are representatives of the same species. The phylogenetic distance to any validly described taxon as indicated by 16S rRNA gene sequence similarities demonstrates that I/26-Cor1T and I/32A-Cor1 represent a novel species, for which the name Hymenobacter aerophilus sp. nov. is proposed, with the type strain I/26-Cor1T (= DSM 13606T = LMG 19657T). I/32A-Cor1 (= DSM 13607 = LMG 19658) is another strain of the species Hymenobacter aerophilus. Since the taxonomic status of strain I/74-Cor2 within the genus Hymenobacter was not determined unambiguously, it is designated Hymenobacter sp. I/74-Cor2 (= DSM 13611 = LMG 19659).

Air Microbiology↗