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PubMed2001

Recovery of commercially produced Bacillus thuringiensis var. israelensis and Bacillus sphaericus from tires and prevalence of bacilli in artificial and natural containers.

We conducted surveys to identify the species of spore-forming bacteria present in natural and artificial containers. Most of our samples came from Illinois. Identification was based on the cellular fatty acid composition of the bacterial cell wall. In addition, we utilized a custom database for commercially produced strains of Bacillus thuringiensis var. israelensis (Bti) and B. sphaericus, to differentiate between larvicidal isolates with commercial or native origin. Native Bti was present at low levels in almost all habitats but was not recovered from bromeliads and metal containers. In temporary woodland pools, 27.9% of the colonies recovered were native Bti. We did not recover larvicidal B. sphaericus in untreated habitats. VectoBac and VectoLex were applied to tires containing water and the tires were sampled 3 months and 9 months after treatment. Isolates of Bti and B. sphaericus with commercial origin were recovered as long as 9 months after application. We noticed numerous cadavers of Aedes triseriatus in several tires 9 months after treatment with VectoBac. We could not determine if this mortality resulted from recycling of Bti in these tires or whether insecticidal crystal proteins from the original treatment were resuspended. Bacillus thuringiensis var. israelensis isolates with commercial ancestry were recovered from untreated tires 9 months after application. Isolates of larvicidal B. sphaericus that differed from the bacteria in VectoLex were also recovered from untreated tires.

Animals↗
PubMedDate not supplied

[The relation of membrane proteins to primary oxidation of higher ri-alkanes by Pseudomonas denitrificans].

Protein composition of enriched with cell walls membrane preparations from two Ps. denitrificans mutants is comparatively studied. Mutants have a genetic blocking of first steps of higher n-alkanes oxidation. Differences in three protein components are found using disc electrophoresis in a system containing sodium dodecylsulphate. This is supposed to be an evidence of possible relation of changed mutant proteins to enzymatic alkanes oxidation.

Alkanes↗
PubMed1988

A study of the antifungal activity of LY121019, a new echinocandin derivative.

LY121019 is a cyclic peptide antibiotic of the echinocandin group, which is characterized by strong anti-Candida activity (in particular against Candida albicans) as well as by low experimental toxicity. Its anti-Candida activity is thought to be due to an inhibition of the synthesis of beta-glucan, an essential cell wall polysaccharide. The different composition of culture media or the presence of animal serum did not show adverse effects on LY121019's anti-Candida activity and the addition of reducing compounds such as cysteine and hydroquinone did not manifest a negative influence. Analogously the anti-Candida activity was not influenced when C. albicans was grown under aeration. The activity of LY121019 was very high against the mycelial form of C. albicans even when this form was developed in the presence of animal serum.

Antifungal Agents↗
PubMed1986

Rapid visualization of three common fungi using fluorescein-conjugated lectins.

The feasibility of using fluorescein-conjugated lectins to visualize and differentiate three fungi commonly involved in ophthalmic mycoses was evaluated. Using a panel of fluorescein-conjugated lectins, Candida albicans, Aspergillus fumigatus, and Fusarium solani were rapidly and reproducibly visualized in in vitro culture isolates, as well as in tissue samples and fixed histopathologic specimens taken from experimental mycoses. Additionally, Aspergillus and Fusarium were consistently differentiated from Candida. The binding affinities of the different lectins corresponded well with the individual sugar composition of the fungal cell walls.

Animals↗
PubMed1996

Elucidation of factors associated with the maturity-related decline in degradability of big bluestem cell wall.

Big bluestem (Andropogon gerardii) forage samples were collected from three ungrazed, annually burned pastures at 38, 58, and 97 d after burning. Cell wall material received five treatments: chlorite delignification, chlorite delignification plus alkali extraction, NaOH, NaOCH3 in methanol, or NaBH4. Untreated and treated cell walls were analyzed for carbohydrate composition (glucose, xylose, arabinose, galactose, and uronic acids), acetyl bromide lignin, acid detergent lignin, alkali-labile phenolics (p-coumaric and ferulic acids), acetyl groups, and 24- and 72-h in vitro degradabilities of neutral monosaccharides. A number of compositional features, notably concentrations of xylose, core lignin as measured by acetyl bromide lignin, alkali-labile phenolics, and acetyl groups, were well related to the decline in cell wall degradability that occurred with increasing maturity of big bluestem. p-Coumaric acid increased with increasing maturity to a greater extent than did ferulic acid. Acid detergent lignin was not well related to degradability of the cell wall for either the untreated or chemically treated cell walls. Chemical treatments failed to identify any particular cell wall component as being most inhibitory. However, all treatments improved in vitro degradability of the carbohydrate fraction, indicating that components contributing to the undegradability of big bluestem cell wall are sensitive to chemical alteration. Treatments involving alkali were most effective for improving degradability of big bluestem cell walls.

Aging↗
PubMed2004

In vitro synthesis of a crystalline (1-->3,1-->4)-beta-D-glucan by a mutated (1-->3,1-->4)-beta-D-glucanase from Bacillus.

Oligo- and poly-saccharides have a large number of important biological functions, and they occur in natural composite materials, such as plant cell walls, where they self-assemble during biosynthesis in a poorly understood manner. They can also be used for the formation of artificial composite materials with industrial applications. Fundamental and applied research in biology and nanobiotechnology would benefit from the possibility of synthesizing tailor-made oligo-/poly-saccharides. In the present paper, we demonstrate that such syntheses are possible using genetically modified glycoside hydrolases, i.e. glycosynthases. The ability of the endoglycosynthase derived from Bacillus (1-->3,1-->4)-beta-D-glucanase to catalyse self-condensation of sugar donors was exploited for the in vitro synthesis of a regular polysaccharide. The specificity of the enzyme allowed the polymerization of alpha-laminaribiosyl fluoride via the formation of (1-->4)-beta-linkages to yield a new linear crystalline (1-->3,1-->4)-beta-D-glucan with a repeating 4betaG3betaG unit. MS and methylation analyses indicated that the in vitro product consisted of a mixture of oligosaccharides, the one having a degree of polymerization of 12 being the most abundant. Morphological characterization revealed that the (1-->3,1-->4)-beta-D-glucan forms spherulites which are composed of platelet crystals. X-ray and electron diffraction analyses allowed the proposition of a putative crystallographic structure which corresponds to a monoclinic unit cell with a =0.834 nm, b =0.825 nm, c =2.04 nm and gamma=90.5 degrees. The dimensions of the ab plane are similar to those of cellulose I(beta), but the length of the c -axis is nearly twice that of cellulose I. It is proposed that four glucose residues are present in an extended conformation along the c -axis of the unit cell. The data presented show that glycosynthases represent promising enzymic systems for the synthesis of novel polysaccharides with specific and controlled structures, and for the analysis in vitro of the mechanisms of polymerization and crystallization of polysaccharides.

Bacillus↗
PubMed1981

Variations in properties of Nocardia asteroides resulting from growth in the cell wall-deficient state.

Several revertants possessing a cell wall were obtained from L-forms of Nocardia asteroides 10905. These L-form revertants differed from the parent in respect to colonial and cellular morphology, pigmentation, metabolic, capacities, cell wall structure, and mycolic acid composition. These data suggest a possible mechanism for the taxonomic heterogeneity and phenotypic diversity observed among N. asteroides strains.

Carbohydrate Metabolism↗
PubMed1984

Actinomyces denticolens Dent & Williams sp. nov: a new species from the dental plaque of cattle.

Six strains of actinomyces isolated from the dental plaque of cattle were assigned presumptively to the genus Actinomyces on the basis of Gram reaction, cellular and colony morphology and acid end-products of metabolism. This assignment was confirmed by the peptidoglycan composition which is shared with Actinomyces species from dental plaque. These cattle strains formed a homogeneous group on the basis of cell wall carbohydrate components, DNA base composition, polypeptide molecular weight distribution and physiological reactions but could not be classified with any recognised species of Actinomyces. A new taxon Actinomyces denticolens is proposed for these strains.

Actinomyces↗
PubMedDate not supplied

[The properties of cell wall hydrolysates of Streptococcus group A].

Products obtained from lysis in the cell wall of group A streptococcus have been studied in different growth phases: at the end of the exponential phase and in the stationary one. Endo-beta-N-acetylmuramidase extracted from the culture liquid of Streptomyces levoris 96 has been used for lysis of streptococcus. It is stated that streptococcus cell walls isolated at different growth stages differ in the protein and polysaccharide content. High content of protein in the cell wall of a young culture makes lower the initial rate of the walls' hydrolysis by endo-beta-N-acetylmuramidase. However, with the enzyme penetration into peptidoglycan the rate of hydrolysis of cell walls gets higher and after four-hour incubation the lysis degree of walls of the 16- and 8-hour cultures reaches the equal value (63%). Studies in the protein composition of lysates of the streptococcus cell walls have shown that they contain at least 12 proteins most of which are acid and neutral ones.

Cell Wall↗
PubMed1980

Genetic transformation with cell wall-associated deoxyribonucleic acid in Bacillus subtilis.

Cell walls from bacillus subtilis 168 were prepared by conventional methods and found to contain deoxyribonucleic acid (DNA). In transformation assays, after autolysis, it was found that two major regions of the chromosome were selectively enriched in the wall preparations. One region clustered around the replication origin and is represented by the markers purA16, ts8132, thiC5, sacA321, and hisA1. The other region included the replication terminus with representative loci metB10, citK5, gltA292, and pyrA1. All other (internal) loci which were examined showed no statistical enrichment. The two areas of enrichment were similar to but more extensive than those reported for membrane-DNA complexes. The wall preparations also contained protein and lipid, indicating a possible membrane involvement. Analyses of the cell walls revealed that the fatty acid composition of the membrane component was not typical of the for B. subtilis protoplast membranes or for lipoteichoic acids. In addition, radioiodination of cell wall autolysates, followed by gel electrophoresis and autoradiography, demonstrated the presence of proteins not readily detectable in bulk protoplast membranes or on the surfaces of intact cells. These data suggest that a unique component of the membrane and regions of the B. subtilis genome involved in DNA replication events are tightly associated with cell walls. The binding of DNA-membrane complexes to the "rigid" cell wall and the replication of the wall could be a mechanism by which the segregation of growing chromosomes occurs.

Bacillus subtilis↗
PubMed1981

[Characterization of cell wall constituents involved in the flocculation of Saccharomyces uvarum yeast strains].

Cell walls of flocculent strains (0006) and non flocculent strains (0019) of Saccharomyces uvarum (Carlsbergensis), grown in different media and taken in both growth and stationary phases, were treated with water and with 2 per cent (W/V) potassium hydroxide. This treatment yielded four fractions (FI, FII, FIII and FR). The fractions FI isolated from the flocculent cell walls contained more mannose and less protein than the corresponding fractions FI isolated from the non flocculent cell walls. The amino-acid composition was also different between the two types of fractions. A radioactive labelling technique revealed that the FI and the walls from flocculent cells bound on average two to three times as much 45Ca as did the FI and the walls from non flocculent yeast. The substitution of carboxyl groups in FI and walls with glycine methyl ester led to a great drop of the 45Ca binding capacity. This result suggests that carboxyl groups of the cell walls are involved in the flocculation process. But flocculation seems to be a phenomenon more complex than the simple formation of a Ca2+ bridge, the involvement of "lectin like" components easily removed from the cell walls, should not be rejected.

Amino Acids↗
PubMed2004

A link between sterol biosynthesis, the cell wall, and cellulose in Arabidopsis.

A crucial role for sterols in plant growth and development is underscored by the identification of three Arabidopsis sterol biosynthesis mutants that exhibit embryonic defects: fackel (fk), hydra1 (hyd1), and sterol methyltransferase 1/cephalopod (smt1/cph). We have taken a dual approach of sterol profiling and ultrastructural analysis to investigate the primary defects underlying the mutant phenotypes. Comprehensive gas chromatography GC-MS analysis of hyd1 in comparison to fk reveals an abnormal accumulation of unique sterol intermediates in each case. Sterol profiling of the fk hyd1 double mutant provides genetic evidence that FK C-14 reductase acts upstream of HYD1 C-8,7 isomerase. Despite distinct differences in sterol profiles, fk and hyd1 as well as smt1/cph share ultrastructural features such as incomplete cell walls and aberrant cell wall thickenings in embryonic and post-embryonic tissues. The common defects are coupled with ectopic callose and lignin deposits. We show that all three mutants exhibit a deficiency in cellulose, but are not reduced in pectin and sugars of the cell wall and cytosol. The sterol biosynthesis inhibitors 15-azasterol and fenpropimorph also cause cell wall gaps in dividing root cells and a reduction in bulk cellulose, corroborating that the cell wall abnormalities are due to altered sterol composition. Our results demonstrate that sterols are crucial for cellulose synthesis in the building of the plant cell wall.

Arabidopsis↗
PubMed1992

Peptidoglycan composition of a highly methicillin-resistant Staphylococcus aureus strain. The role of penicillin binding protein 2A.

All clinical isolates of methicillin-resistant Staphylococcus aureus contain an extra penicillin binding protein (PBP) 2A in addition to four PBPs present in all staphylococcal strains. This extra PBP is thought to be a transpeptidase essential for the continued cell wall synthesis and growth in the presence of beta-lactam antibiotics. As an approach of testing this hypothesis we compared the muropeptide composition of cell walls of a highly methicillin-resistant S. aureus strain containing PBP2A and its isogenic Tn551 derivative with reduced methicillin resistance, which contained no PBP2A because of the insertional inactivation of the PBP2A gene. Purified cell walls were hydrolyzed into muropeptides which were subsequently resolved by reversed-phase high-performance liquid chromatography and identified by chemical and mass spectrometric analysis. The peptidoglycan composition of the two strains were identical. Both peptidoglycans were highly cross-linked mainly through pentaglycine cross-bridges, although other, chemically distinct peptide cross-bridges were also present including mono-, tri-, and tetraglycine; alanine; and alanyl-tetraglycine. Our experiments provided no experimental data for a unique transpeptidase activity associated with PBP2A.

Amino Acid Sequence↗
PubMed1998

Variations of the envelope composition of Bacillus subtilis during growth in hyperosmotic medium.

The envelope properties of B. subtilis cultures grown in LB and LBN hyperosmotic media (LB + 1.5 M NaCl) were compared. Since hypertonic cultures showed a Spo-phenotype, a Spo-mutant grown in LB was also analyzed. LBN cultures showed extensive filamentation and presented different sensitivities toward phage infection (phi29 and phi105), or antibiotics whose targets are at wall (lysozyme, penicillin G) or membrane level (polymyxin B, phosphonomycin). Results of the biochemical composition revealed that during hyperosmotic growth, the cell wall increased in thickness, and among the membrane lipids, glycolipid and cardiolipin increased in parallel with a decrease in phosphatidylglycerol. The fatty acid composition was also modified, and an increase in saturated straight chain with a decrease of saturated iso-branched fatty acids was observed. The increase of monounsaturated 18-1 (omega-9) fatty acid was probably related to the absence of sporulation observed in hypertonic media, since its increase has been shown to inhibit the KinA sensor of sporulation. The significance of the other wall and membrane composition variations (and hydrophobic surface properties) in relation to the osmotic adaptation are discussed.

Bacillus subtilis↗
PubMed1985

Unusual cellular fatty acids and distinctive ultrastructure in a new spiral bacterium (Campylobacter pyloridis) from the human gastric mucosa.

Spiral bacteria, named Campylobacter pyloridis, were obtained from endoscopic biopsies of the gastric antrum of 14 patients with active chronic gastritis. Methyl esters of their cellular fatty acids were prepared by acid-catalysed transmethylation of whole cells. Their major fatty acids were tetradecanoic acid (14:0) and cis-9,10-methyleneoctadecanoic acid (19:0 delta), with a very small amount of hexadecanoic acid (16:0). This is markedly different from the fatty acids of other Campylobacter sp. whose major fatty acids are hexadecanoic, octadecenoic (18:1) and hexadecenoic acids (16:1). This is also different from other enterobacteria. Thin-section electronmicroscopy of gastric mucosal biopsies, and negative staining of cultured C. pyloridis, revealed features that differ from those of other campylobacters so far studied. C. pyloridis has a smooth not a rugose surface and multiple unipolar flagella of the sheathed type, each with a terminal bulb. Flagellar sheaths were in continuity with the unit membrane of the outer cell wall. The proposed species C. pyloridis does not belong among the spirochaetes and its DNA composition is incompatible with membership of the genera Spirillum or Vibrio but is compatible with Campylobacter. Thus C. pyloridis is either an atypical member of the genus Campylobacter, the limits of which may have to be redefined to accommodate the new species, or a representative of a new genus.

Base Composition↗
PubMed1984

Genetic control of a structural polymer of the Neurospora crassa cell wall.

The heteropolysaccharide present in fraction 1 of the Neurospora crassa cell wall has been characterized in wild-type and morphological mutant strains of this fungus. Single and double mutations have been studied to determine possible genetic interactions controlling the chemical composition of such heteropolysaccharides . Single mutations studied were peak-2, scumbo ( FGSC 49), ragged ( FGSC 296), and crisp -1 ( FGSC 488). Double mutations studied were peak-2, scumbo ( FGSC 419), and ragged crisp -1. In all these strains, the main constituents of the heteropolysaccharide were glucose, mannose and galactose. Glycosidic linkages binding these neutral sugars have been identified by gas-liquid chromatography. A chemical structure of fraction I heteropolysaccharide is proposed. The results obtained with double mutants suggest the existence of genetic interactions, such as complementation or additive effects of lesions of different genes, to control the chemical composition and structure of the cell wall and the morphology of N. crassa mycelium.

Acetylation↗
PubMed2003

A mechanics model for the compression of plant and vegetative tissues.

The mechanics analysis of plant or vegetable tissue under a compressive stress has been developed based on large deformation elasticity theory. The tissue was treated as a lattice of regular perfect three-dimensional hexagonal cells. The cell walls were assumed to be impermeable under the time-scale of the loading. The cell walls of plants and vegetables are polymeric composite materials, consisting of a relatively amorphous matrix and a highly structured network of microfibrils embedded in the cell wall matrix. The micromechanical features of the individual cells have been related to the macroscopic properties of the whole tissue. The effects of microfibrillar stiffening factors k(1) and k(2), the cell wall matrix property alpha and the initial cell expansion ratio nu(i) on the compressive behaviour of a plant or vegetable tissue have been investigated. The predicted results have also been related to some experimental evidence.

Cell Wall↗
PubMed1998

A dual labelling method for measuring uptake of low molecular weight compounds into the pathogenic yeast Candida albicans.

In contrast to other eukaryotic cells the pathogenic yeast Candida albicans is resistant to many structurally unrelated metabolic inhibitors. Reduced permeability due to the cell wall and/or altered plasma membrane composition is thought to be at least partly responsible for this phenomenon. To study the uptake of low molecular weight compounds into C. albicans we developed a dual labelling method. Intact cells, metabolically inactivated cells, spheroplasts or membrane fragments of C. albicans were incubated with various [14C]-labelled compound in the presence of [3H]-labelled water. After separation of cells and supernatant isotope ratios [3H]/[14C] were determined. Quotients of the isotope ratios from cells and supernatant, called enrichment coefficients, were calculated under all four conditions. The enrichment coefficients indicated whether a compound can enter C. albicans cells, is trapped within the cell wall, is enriched in the lipophilic membrane compartment, is actively accumulated or actively exported by multidrug resistance carriers. We used six structurally unrelated compounds to test our method. We found no evidence for a general impermeability of C. albicans.

Anti-Bacterial Agents↗