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PubMed1994

[Pneumonia complicated by bacteremia with Stomatococcus mucilaginosus].

A rare strain of Stomatococcus mucilaginosus (formerly Micrococcus) was isolated from blood of a patient after pneumonia, which was causing an enlargement of lymph nodes and groin fistula. Chemical composition of cell wall of this microorganism (analysis of amino acids and diagnostically important sugars), elementary composition of lipids (fatty acids, phospholipids and glycolipids) and molar percentage of guanine and cytosine (%GC), were determined. Results completely agreeable with results published elsewhere were obtained which resulted in reclassification of this species (Kocur (1982, Int. J.Sys.Bacterial. 32, 374-377)). This case indicates that some relative pathogens require modern diagnostic methods and when not recognized in cases of acquired or directed immunosuppression can create a serious threat.

Bacteremia↗
PubMed1993

A new Brevibacterium sp. isolated from infected genital hair of patients with white piedra.

A new aerobic gram-positive non-sporeforming bacillus has been isolated from infected genital hair of patients with white piedra in association with Trichosporon beigelii. This species has been characterised morphologically, nutritionally, by DNA base composition, cell-wall analysis and cellular fatty-acid profile on the basis of 14 isolates. The G+C content of DNA is 63.05 mol%. Cell walls possess meso-diaminopimelic acid (Type IV) and the sugars glucose, galactose, xylose and ribose; mycolic acids are not present. The species has a distinct colonial and microscopic morphology, is strongly proteolytic and produces methanethiol. These findings and the cellular fatty-acid profile are compatible with the genus Brevibacterium. A new species is proposed based on the following characters: colonial and microscopic growth and morphology; conditions for rod-to-coccus cycle; ribose utilisation; and tellurite reduction. The type strain has been named Brevibacterium mcbrellneri E2cr (ATCC 49030). The strong proteolytic properties may be the mechanism of pathogenesis.

Anti-Bacterial Agents↗
PubMed2003

Effect of germination on the carbohydrate composition of the dietary fiber of peas (Pisum sativum L.).

The effect of different conditions of pea germination on dietary fiber (DF) composition was studied. Insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) were subjected to acid hydrolysis, and the resultant neutral sugars, uronic acids, and Klason lignin were quantified. Germinated peas exhibited significantly higher contents of total dietary fiber (TDF) than the raw sample, due to the increases of both DF fractions. Under darkness conditions, germination exhibited the highest contents of IDF and SDF. Decreasing IDF/SDF ratios showed that the carbohydrate changes did not take place to the same extent during germination, the SDF fraction being the most affected. The detailed chemical composition of fiber fractions reveals increases of cellulose in the IDF of germinated samples, whereas SDF exhibits a decrease of pectic polysaccharides and also increases of polysaccharides rich in glucose and mannose. The DF results were corroborated by a comparative examination of the cell wall carbohydrate composition.

Cell Wall↗
PubMed2003

Real-time imaging of the surface topography of living yeast cells by atomic force microscopy.

Atomic force microscopy (AFM) was used to image the surface topography of living Saccharomyces cerevisiae cells at high resolution and to monitor enzyme digestion of the cell wall in real time. Apart from the presence of bud scars, the surface of native cells imaged in aqueous solution was homogeneous and smooth. Topographic images of the surface were recorded to a lateral resolution of 2 nm without significant modification of the surface morphology. Successive images of single cells were collected at fixed time intervals following addition of protease and amyloglucosidase solutions. Protease caused a progressive increase of surface roughness. Large depressions surrounded by protruding edges, approximately 50 nm in height, were formed and attributed to the erosion of the mannoprotein outer layer. By contrast, no modification of the cell surface was noted upon addition of amyloglucosidase, which was consistent with the cell wall biochemical composition. These results indicate that AFM is a complementary tool to electron microscopy in that it allows the surface of living cells to be explored directly in real time.

Cell Wall↗
PubMed2004

Arylamine N-acetyltransferase is required for synthesis of mycolic acids and complex lipids in Mycobacterium bovis BCG and represents a novel drug target.

Mycolic acids represent a major component of the unique cell wall of mycobacteria. Mycolic acid biosynthesis is inhibited by isoniazid, a key frontline antitubercular drug that is inactivated by mycobacterial and human arylamine N-acetyltransferase (NAT). We show that an in-frame deletion of Mycobacterium bovis BCG nat results in delayed entry into log phase, altered morphology, altered cell wall lipid composition, and increased intracellular killing by macrophages. In particular, deletion of nat perturbs biosynthesis of mycolic acids and their derivatives and increases susceptibility of M. bovis BCG to antibiotics that permeate the cell wall. Phenotypic traits are fully complemented by introduction of Mycobacterium tuberculosis nat. We infer from our findings that NAT is critical to normal mycolic acid synthesis and hence other derivative cell wall components and represents a novel target for antituberculosis therapy. In addition, this is the first report of an endogenous role for NAT in mycobacteria.

Anti-Bacterial Agents↗
PubMed2004

Digestibility of carbohydrates in growing pigs: a comparison between the T-cannula and the steered ileo-caecal valve cannula.

We compared the determination of ileal and total tract digestibility of carbohydrates in five experimental diets using a double 5 x 5 Latin square design involving a total of 10 cannulated pigs; half of the pigs were equipped with a simple T-cannula and the other half with steered ileo-caecal valve (SICV)-cannula. The diets consisted of nitrogen-free mixture and soya bean meal, sunflower meal, peas or rape seed cake diluted to about 180 g/kg DM protein with the nitrogen-free mixture. There was no significant difference in the digestibility values using the two types of cannulas with regard to organic matter, sugars (sum of glucose, fructose and sucrose), alpha-galactosides (sum of raffinose, stachyose and verbascose), starch, cellulose, total non-cellulosic polysaccharides (NCP) and insoluble NCP constituents. The digestibility values for the NCP residues arabinose and galactose, however, were estimated higher but with a lower variability with the SICV-cannula compared with the T-cannula. The type of cannula did no influence the estimation of the total tract digestibility for any of the major dietary constituents, but the total tract digestibility was slightly more variable when the pigs were equipped with the SICV-cannula compared with the T-cannula. There was no difference in the ileal digestibility of sugars, alpha-galactosides, cellulose and the NCP arabinose and uronic acids residues among the experimental diets, while the ileal digestibility of starch and the remaining NCP sugar residues varied between diets. The total tract digestibility was complete for sugars, alpha-galactosides and starch, whereas the digestibility of the cell wall constituents varied in accordance with the polymeric composition of the cell walls. It was concluded that ileal digesta samples from SICV-cannula are more homogenous than those from the T-cannula. In cases where the precision of each determination is crucial, the SICV-cannula should be the option.

Animal Feed↗
PubMed1989

Effects of cilofungin (LY121019) on carbohydrate and sterol composition of Candida albicans.

Cilofungin (LY 121019) is a novel analogue of echinocandin B with potent activity against Candida albicans. The effects of cilofungin on the sterol and cell wall carbohydrate composition of Candida albicans were investigated. Exposure of Candida albicans to cilofungin resulted in a 55-60% decrease in ergosterol and a 4-13% decrease in lanosterol content relative to controls. Carbohydrate analysis revealed a 72-79% decrease in glucan content and no significant decrease in mannan or chitin content relative to controls. These studies suggest that cilofungin specifically inhibits glucan synthesis in Candida albicans and thus may be less toxic to mammalian cells. The effects of cilofungin on sterol composition may be non-specific and will require additional investigation.

Candida albicans↗
PubMedDate not supplied

Use of molecular cytology to study the structure and biology of phytopathogenic and mycorrhizal fungi.

Molecular cytology, that is, the in situ localization of selected molecules by labeling with lectins, enzymes, and antibodies, has made a major contribution to our understanding of the structure and biology of fungi and is increasingly becoming an integral part of molecular, genetic, and biochemical studies. The review presented in this article concentrates on recent advances in the application of molecular cytology in investigations of the structure and biology of phytopathogenic and mycorrhizal fungi and of the molecular basis of their infection of host plants. The review examines details of the structure and molecular composition of fungal cell walls revealed by lectin, enzyme, and antibody labeling. Molecular composition is shown to vary according to taxonomic relationships and as a reflection of differences in cell type, location within the cell, and within thickness of the wall. Sites of synthesis and secretion of wall components are also detected through the labeling of selected molecules. In situ labeling of cytoskeletal elements, microtubules and actin microfilaments, has provided much information on the role of these elements in tip growth, organelle distribution, and spore development. Molecular cytology, particularly through the generation of monoclonal antibodies, has also revealed new and exciting information on specialized infection structures formed by fungi in order to infect host plants. The sites of storage and secretion of adhesives and degradative enzymes have been documented, as have surface specializations that may be associated with avoidance of detection by the host. In addition, in situ labeling with enzymes and antibodies has aided studies of the host defense response, including mechanisms of detection of fungal elicitor molecules, changes in wall composition, and the secretion of antifungal compounds. With the increasing production of monoclonal antibodies to fungal molecules, molecular cytology promises to continue to make an important contribution to our understanding of fungal cell structure and function in the future.

Cell Adhesion↗
PubMed2006

C-terminal WxL domain mediates cell wall binding in Enterococcus faecalis and other gram-positive bacteria.

Analysis of the genome sequence of Enterococcus faecalis clinical isolate V583 revealed novel genes encoding surface proteins. Twenty-seven of these proteins, annotated as having unknown functions, possess a putative N-terminal signal peptide and a conserved C-terminal region characterized by a novel conserved domain designated WxL. Proteins having similar characteristics were also detected in other low-G+C-content gram-positive bacteria. We hypothesized that the WxL region might be a determinant of bacterial cell location. This hypothesis was tested by generating protein fusions between the C-terminal regions of two WxL proteins in E. faecalis and a nuclease reporter protein. We demonstrated that the C-terminal regions of both proteins conferred a cell surface localization to the reporter fusions in E. faecalis. This localization was eliminated by introducing specific deletions into the domains. Interestingly, exogenously added protein fusions displayed binding to whole cells of various gram-positive bacteria. We also showed that the peptidoglycan was a binding ligand for WxL domain attachment to the cell surface and that neither proteins nor carbohydrates were necessary for binding. Based on our findings, we propose that the WxL region is a novel cell wall binding domain in E. faecalis and other gram-positive bacteria.

Amino Acid Sequence↗
PubMed1990

Comparison of ripening processes in intact tomato fruit and excised pericarp discs.

Physiological processes characteristic of ripening in tissues of intact tomato fruit (Lycopersicon esculentum Mill.) were examined in excised pericarp discs. Pericarp discs were prepared from mature-green tomato fruit and stored in 24-well culture plates, in which individual discs could be monitored for color change, ethylene biosynthesis, and respiration, and selected for cell wall analysis. Within the context of these preparation and handling procedures, most whole fruit ripening processes were maintained in pericarp discs. Pericarp discs and matched intact fruit passed through the same skin color stages at similar rates, as expressed in the L(*)a(*)b(*) color space, changing from green (a(*) < -5) to red (a(*) > 15) in about 6 days. Individual tissues of the pericarp discs changed color in the same sequence seen in intact fruit (exocarp, endocarp, then vascular parenchyma). Discs from different areas changed in the same spatial sequence seen in intact fruit (bottom, middle, top). Pericarp discs exhibited climacteric increases in ethylene biosynthesis and CO(2) production comparable with those seen in intact fruit, but these were more tightly linked to rate of color change, reaching a peak around a(*) = 5. Tomato pericarp discs decreased in firmness as color changed. Cell wall carbohydrate composition changed with color as in intact fruit: the quantity of water-soluble pectin eluted from the starch-free alcohol insoluble substances steadily increased and more tightly bound, water-insoluble, pectin decreased in inverse relationship. The cell wall content of the neutral sugars arabinose, rhamnose, and galactose steadily decreased as color changed. The extractable activity of specific cell wall hydrolases changed as in intact fruit: polygalacturonase activity, not detectable in green discs (a(*) = -5), appeared as discs turned yellow-red (a(*) = 5), and increased another eight-fold as discs became full red (a(*) value +20). Carboxymethyl-cellulase activity, low in extracts from green discs, increased about six-fold as discs changed from yellow (a(*) = 0) to red.

Journal Article↗
PubMed1990

Changes in the Endosperm Cell Walls of Two Datura Species before Radicle Protrusion.

The possibility of an association between changes in cell walls of the micropylar portion of the endosperm and the induction of germination was explored in seeds of Datura ferox and Datura stramonium. The structure of the inner surface of the endosperm was studied by scanning electron microscopy and the composition of cell wall polysaccharides analyzed by gas chromatography and gas chromatography-mass spectrometry. Both scanning electron microscope images and chemical analysis showed changes in the micropylar portion of the endosperm in induced seeds before radicle protrusion. The inner surface of the endosperm appeared eroded, and in some areas, wall material seemed to be missing. The content of the main component of the cell wall polysaccharides, containing predominantly 4-linked mannose, decreased well before the emergence of the radicle through the endosperm. We propose that the degradation of a mannan type polysaccharide is an important factor in the reduction in mechanical strength of the endosperm, thus facilitating germination.

Journal Article↗
PubMed2000

Leifsonia poae gen. nov., sp. nov., isolated from nematode galls on Poa annua, and reclassification of 'Corynebacterium aquaticum' Leifson 1962 as Leifsonia aquatica (ex Leifson 1962) gen. nov., nom. rev., comb. nov. and Clavibacter xyli Davis et al. 1984 with two subspecies as Leifsonia xyli (Davis et al. 1984) gen. nov., comb. nov.

The new genus Leifsonia gen. nov. with two new species, Leifsonia poae sp. nov. (type strain VKM Ac-1401T) and Leifsonia aquatica (ex Leifson 1962) nom. rev., comb. nov. (the type species, with VKM Ac-1400T = DSM 20146T = JCM 1368T as type strain), is proposed to accommodate bacteria found in Poa annua root gall, induced by the nematode Subanguina radicicola, and 'Corynebacterium aquaticum' Leifson 1962. Further, it is proposed to reclassify Clavibacter xyli Davis et al. 1984 with two subspecies in the new genus as Leifsonia xyli (Davis et al. 1984) comb. nov., Leifsonia xyli subsp. xyli (Davis et al. 1984) comb. nov. and Leifsonia xyli subsp. cynodontis (Davis et al. 1984) comb. nov. Members of the proposed genus are characterized by coryneform morphology, peptidoglycans based upon 2,4-diaminobutyric acid, the major menaquinone MK-11, phosphatidylglycerol and diphosphatidylglycerol as principal phospholipids, the high content of anteiso- and iso-branched saturated fatty acids, and a DNA G+C base composition of 66-73 mol%. They form a distinct phylogenetic branch attached to the line of descent of Agromyces spp. The new and reclassified species of the new genus clearly differ from each other phylogenetically and phenetically and can be recognized by their morphologies, the cell wall sugar composition, the requirement of complex media for growth, and numerous physiological characteristics, including the oxidase reaction.

Actinomycetales↗
PubMed1990

Chemotaxonomy of yeasts.

The present review deals with chemotaxonomic methods for yeasts. DNA base composition, which is expressed as molar percentages of guanine plus cytosine (G + C), is fitted for description of a new species and serves exclusionary functions. G + C content range among species within a genus is often 10% or less. Larger ranges may indicate an amalgam of genera. Typing and mapping of DNA may also be used for taxonomy. Strains showing 65% or greater relatedness after DNA-DNA hybridization may be considered members of the same species. With rRNA-DNA homology assessment, intrageneric relationships established are not usually meaningful, but intergeneric distances can be resolved. rRNA can be used for examining phylogenetic diversity of yeasts and alloenzyme variation to calculate genetic distances among large yeast populations. Furthermore, heterogeneity in coenzyme Q pattern, cytochrome spectra, composition of cell wall glucan, mannan, and chitin, and cellular fatty acids may serve chemotaxonomic purposes.

Base Composition↗
PubMed2004

Inhibition of adherence of Candida albicans and Candida dubliniensis to a resin composite restorative dental material by salivary secretory IgA and monoclonal antibodies.

OBJECTIVE: The attachment of Candida to oral surfaces is a crucial step in the colonization of the oral cavity and the eventual development of oral diseases caused by this microorganism. Inhibition of adhesion is one of the strategies currently studied to prevent Candida infections. The main objective of this study was to investigate the inhibitory effect of the human salivary components on the adherence of Candida albicans and C. dubliniensis to Herculite, a widely used resin composite restorative dental material. We have also investigated the influence on the adherence of three monoclonal antibodies (mAbs) directed against C. albicans cell wall antigens. DESIGN: The adhesion of three strains of C. albicans and one strain of C. dubliniensis was studied by a visual method after incubating the fungus and the resin in presence and in absence of human whole saliva, secretory immunoglobulin A (sIgA) and three mAbs directed against C. albicans cell wall surface antigens. RESULTS: Adherence of C. albicans was inhibited by whole saliva (41.7%), salivary sIgA (55.7%) and the salivary components that bind to the cell wall (36.7%). Whole saliva significantly reduced the adhesion of C. dubliniensis to Herculite to 45.3% of the control level. Saliva previously adsorbed with fungal cells or sIgA depleted saliva had no effect on adherence. An inhibition in the adhesion of C. albicans and C. dubliniensis to Herculite similar to that shown by whole saliva was also observed when mAbs C7 and 26G7 were used. However, mAb 21E6 increased adhesion of all the strains to Herculite. CONCLUSIONS: The results suggest that sIgA, as well as whole saliva, are important in blocking adherence of C. albicans and C. dubliniensis to Herculite and that this effect can be reproduced with mAbs directed against the cell wall surface of C. albicans.

Analysis of Variance↗
PubMed1987

Structural studies of cell wall polysaccharides from Bifidobacterium breve YIT 4010 and related Bifidobacterium species.

The chemical compositions of the cell walls obtained from 8 strains in 5 species of Bifidobacterium were analyzed. These cell walls were shown to be composed of peptidoglycan and polysaccharide moieties. Some variations with respect to contents of neutral sugars and content of phosphorus were observed with some cell wall preparations from the same species. The neutral polysaccharides in cell walls of 4 strains of Bifidobacterium (B. bifidum YIT 4007, B. breve YIT 4010, B. infantis YIT 4025, and B. longum ATCC 15707) were purified and their chemical structures were analyzed. One of these polysaccharides, obtained from B. breve YIT 4010, was analyzed in detail by GLC, 1H- and 13C-NMR spectroscopic analyses, methylation, Smith degradation and acetolysis, and the results suggested the following structure for the repeating unit of the polysaccharide: (Formula: see text).

Amino Acids↗
PubMedDate not supplied

[Cell wall of pigmentless variants of Staphylococcus aureus].

Physico-chemical properties and chemical composition of the cell wall of pigmentless variants B-3 and B-6 differ from those of the parent strain of Staphylococcus aureus 209-P. As to morphology, the wall is more thick and loose. The mutants differ also by the phagotype, the ability for sorption of acridine orange, and the rate of sedimentation of cell suspensions. The properties of teichoic acids and the content of peptides in peptidoglycan change in the cell wall of the mutants.

Cell Wall↗