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PubMed1974

Separation of the polypeptides of Chlamydia and its cell walls by polyacrylamide gel electrophoresis.

The polypeptide composition of Chlamydia was examined by acrylamide gel electrophoresis. When the polypeptide patterns of purified infectious elementary bodies (EB) of C. psittaci meningopneumonitis strain, 6BC strain, and C. trachomatis T'ang strain were compared, no significant differences were observed. The polypeptide patterns of whole EB and reticulate bodies (RB) appeared to overlap, but differences were found. In EB cell walls, nine main and several minor bands of polypeptides were observed in gels containing sodium lauryl sulfate, and the eighth main band from the top of the gel stained positive with periodic acid-Schiff reagent. On the other hand, the polypeptides in bands 3, 6, and 8 in EB cell walls were missing or minor in RB cell walls, and the ninth band was clearly stained by PAS. Band 8 was also stained slightly. Purified subunits, which occur as a lattice structure on the inside layer of EB cell walls but are largely missing in RB cell walls, contained bands 4, 6, and 8, and band 8 was PAS positive. These results indicate that significant polypeptide synthesis or reorganization in the cell walls occurs during the growth cycle.

Bacterial Proteins↗
PubMed1981

Characterization of a radiation-resistant Acinetobacter.

For characterizing the radiation-resistant Acinetobacter strain FO-1 reported in the previous paper (1980), we investigated the structure of cell wall, the cellular fatty acid composition, and the detailed taxonomic characteristics. The results denoted that the cell division occurred by simple constriction with the formation of a slight septum and the intermediate dense layer between the outer membrane and the plasma membrane was seen, the main components of the cellular fatty acids were oleic acid, palmitic acid, and palmitoleic acid, and that the strain was tolerant to salt and could not produce acids from cellobiose, melibiose, lactose, and ribose.

Acinetobacter↗
PubMedDate not supplied

An assay of relative cell wall porosity in Saccharomyces cerevisiae, Kluyveromyces lactis and Schizosaccharomyces pombe.

We have developed a new assay to determine relative cell wall porosity in yeasts, which is based on polycation-induced leakage of UV-absorbing compounds. Polycations with a small hydrodynamic radius as measured by gel filtration (poly-L-lysine) caused cell leakage independent of cell wall porosity whereas polycations with a large hydrodynamic radius (DEAE-dextrans) caused only limited cell leakage due to limited passage through the cell wall. This allowed the ratio between DEAE-dextran- and poly-L-lysine-induced cell leakage to be used as a measure of cell wall porosity in Saccharomyces cerevisiae, Kluyveromyces lactis and Schizosaccharomyces pombe. Using this assay, we found that the composition of the growth medium affected cell wall porosity in S. cerevisiae. In addition, we could show that cell wall porosity is limited by the number of disulphide bridges in the wall and is dependent on cell turgor. It is argued that earlier methods to estimate cell wall porosity in S. cerevisiae resulted in large underestimations.

Cell Wall↗
PubMed1999

Dietary fibres may protect or enhance carcinogenesis.

Dietary fibre (DF) is widely considered to protect against cancer, especially colorectal cancer. However, a large prospective epidemiological study has shown no apparent effect of DF intake on the development of colorectal cancer. We suggest that this may be because the term DF represents a wide range of materials, some able to protect, but some able to enhance carcinogenesis. This is consistent with data from animal carcinogenesis experiments. Most of the DF in western diets is in the form of plant cell walls, but these vary in their composition and it is unlikely that all types are protective. The few data available indicate that plant cell walls containing suberin or lignin may be the most protective, although they are present in only small amounts in food plants. DFs are also added to foods. These include components obtained from plant cell walls, such as pectins, as well as soluble DFs from other sources. In general, animal carcinogenesis experiments indicate that soluble DFs do not protect and some may enhance carcinogenesis. Few human intervention studies have been done on DF or sources of DF, with the exception of wheat bran, a good source of DF, which has been shown to protect. Possible mechanisms whereby DF may enhance carcinogenesis are discussed. In addition to DFs, resistant starches and non-digestible oligosaccharides are added to foods; these, like DF, escape digestion in the small intestine. However, so far only a few animal carcinogenesis experiments have been reported using these materials, and no human intervention studies. We believe caution should be exercised in the addition of such materials to food.

Animals↗
PubMed1983

Taxonomic study of four yeast strains assimilating methanol.

The new isolated yeasts were very good producers of biomass from methanol. Their taxonomic studies were based on classical classification, GC content of DNA, proton magnetic resonance spectrum of the cell wall mannans and mannan and glucan and chitin contents in the cell walls. The isolates could not be identified with any species described in literature. Considering their special features and some relation to the known species, the isolated yeasts were classified as follows: C-16 as Candida bimundalis var. chlamydospora, C-4 as Candida melinii var. melibiosica, D-3 as Candida silvicola var. melibiosica and M-1 as Torulopsis candida var. nitratophila.

Base Composition↗
PubMed1997

Influence of essential oil of Hyssopus officinalis on the chemical composition of the walls of Aspergillus fumigatus (Fresenius).

The cell walls of the growing hyphae of Aspergillus fumigatus (Fresenius) cultured in the presence or absence of the essential oil of Hyssopus officinalis were isolated and their chemical composition analysed. The presence of the essential oil led to a reduction in levels of neutral sugars, uronic acid and proteins, whereas amino sugars, lipids and phosphorus levels were increased. HPLC analysis of the neutral sugars showed that they consisted mainly of glucose, mannose and galactose, while the amino sugars consisted of glucosamine and galactosamine. The presence of the essential oil in the culture medium induced marked changes in the content of galactose and galactosamine. Cell walls were fractionated by treatment with alkali and acid. The essential oil induced similar alterations in the various fractions with a more marked effect on the major constituents. The alterations were related to changes in the structure of the cells.

Journal Article↗
PubMed1982

Increase of cardiolipin content in Staphylococcus aureus by the use of antibiotics affecting the cell wall.

Effect of antibiotics affecting cell wall synthesis on phospholipid composition in Staphylococcus aureus 209P was examined. Each antibiotic was added in the middle exponential growth phase and the growth was followed turbidimetrically. Penicillin, fosfomycin, cycloserine, moenomycin and cefazolin caused a leveling off of turbidity and growth to cease without lysis. Enramycin and bacitracin were bacteriolytic. Bacteriolytic antibiotics caused a greater increase of cardiolipin content than those that were non-bacteriolytic. The amount of phosphatidylglycerol decreased in proportion to the increment of cardiolipin content. Since bacteriolytic antibiotics bind to undecaprenol, the role of cardiolipin was discussed in relation to the mechanism of synthesis of cell surface materials.

Anti-Bacterial Agents↗
PubMed1979

DNA sequence similarity, cell wall mannans and physiological characteristics in some strains of Candida utilis, Hansenula jadinii and Hansenula petersonii.

The physiological characteristics, proton magnetic resonance spectra of cell wall mannans, DNA base composition and DNA sequence similarity of some strains of Candida utilis, Hansenula jadinii and Hansenula petersonii were examined. It was found that C. utilis was not distinguishable from H. jadinii by any of these criteria. These findings show the close genetic relationship between C. utilis and its perfect form H. jadinii. In contrast, H. petersonii was found to differ from C. utilis and H. jadinii on account of insignificant DNA reassociation as well as a number of other properties.

Ascomycota↗
PubMed2003

Tensile deformation of bacterial cellulose composites.

The polymeric basis for the mechanical properties of primary plant cell walls has been investigated by forming analogous composites based on fermentation of the bacterium Acetobacter xylinus, either alone or in the presence of xyloglucan or pectin. Simultaneous small-angle X-ray scattering and uniaxial deformation experiments has shown how the cellulose microfibrils reorient during deformation. Despite very different stress/strain curves, the reorientation behaviour is similar, regardless of the presence or absence of xyloglucan or pectin. A simple theory has been developed to predict the orientation behaviour. This is qualitatively similar to the measured behaviour, but differs quantitatively.

Bacterial Physiological Phenomena↗
PubMed2005

Determination of non-starch polysaccharides in cereal grains with near-infared reflectance spectroscopy.

Cereal grains contain variable amounts of non-starch polysaccharides, such as arabinoxylans and (1-->3),(1-->4)-beta-glucans (beta-glucans), which are associated with their cell walls. The type and composition of these polysaccharides is of increasing interest in both human and animal nutrition. Reference analysis for these polysaccharides requires the use both enzymic and monosaccharide methods. To evaluate fully the non-starch polysaccharides present in grains, some analysts further distinguish between the soluble and insoluble fractions of these components. Near-infrared reflectance (NIR) spectroscopy provides fast, inexpensive analysis. It is, however, a comparative technique that relies on multivariate calibration of sample spectra and accurate reference analysis. It has the potential to be exploited as a rapid analytical method for nutritionally important polysaccharides. The calibration statistics for arabinoxylans and beta-glucans obtained in this study suggest that NIR can be used in plant breeding, nutritional and product studies to obtain simple and rapid estimates of non-starch polysaccharides. The occurrence of wheats with high cell wall contents together with barleys with high beta-glucan contents is well known. However, to date, this genetic variation has not been extensively exploited for the production of grains for use as human food ingredients.

Calibration↗
PubMed1995

Adherence of Candida albicans to a cell surface polysaccharide receptor on Streptococcus gordonii.

Candida albicans ATCC 10261 and CA2 bound to cells of the oral bacteria Streptococcus gordonii, Streptococcus oralis, and Streptococcus sanguis when these bacteria were immobilized onto microtiter plate wells, but they did not bind to cells of Streptococcus mutans or Streptococcus salivarius. Cell wall polysaccharide was extracted with alkali from S. gordonii NCTC 7869, the streptococcal species to which C. albicans bound with highest affinity, and was effective in blocking the coaggregation of C. albicans and S. gordonii cells in the fluid phase. When fixed to microtiter plate wells, the S. gordonii polysaccharide was bound by all strains of C. albicans tested. The polysaccharide contained Rha, Glc, GalNAc, GlcNAc, and Gal and was related compositionally to previously characterized cell wall polysaccharides from strains of S. oralis and S. sanguis. The adherence of yeast cells to the immobilized polysaccharide was not inhibitable by a number of saccharides. Antiserum raised to the S. gordonii NCTC 7869 polysaccharide blocked adherence of C. albicans ATCC 10261 to the polysaccharide. The results identify a complex cell wall polysaccharide of S. gordonii as the coaggregation receptor for C. albicans. Adherent interactions of yeast cells with streptococci and other bacteria may be important for colonization of both hard and soft oral surfaces by C. albicans.

Candida albicans↗
PubMed1997

Bacillus salexigens sp. nov., a new moderately halophilic Bacillus species.

Bacillus salexigens sp. nov. is proposed based on the characteristics of six moderately halophilic, grampositive, rod-shaped strains isolated from salterns and hypersaline soils located in different geographical areas of Spain. These strains were motile, formed endospores, were strictly aerobic, were catalase and oxidase positive, and contained peptidoglycan of the meso-diamlnopimelic acid type in their vegetative cell walls. The DNA base compositions of these strains ranged from 36.3 to 39.5 mol%, and these organisms constitute a homology group with levels of DNA-DNA homology ranging from 73 to 100%. The 16S rRNA sequence of strain C-20MoT, which was used as the representative strain of these isolates, groups with the 16S rRNA sequences of members of the genus Bacillus, and the highest level of similarity is 95.4%. The type strain is strain C-20Mo (= ATCC 700290 = DSM 11483 = CCM 4646).

Bacillus↗
PubMed2006

Development and application of a suite of polysaccharide-degrading enzymes for analyzing plant cell walls.

To facilitate analysis of plant cell wall polysaccharide structure and composition, we cloned 74 genes encoding polysaccharide-degrading enzymes from Aspergillus nidulans, Aspergillus fumigatus, and Neurospora crassa and expressed the genes as secreted proteins with C-terminal Myc and 6x His tags. Most of the recombinant enzymes were active in enzyme assays, and optima for pH and temperature were established. A subset of the enzymes was used to fragment polysaccharides from the irregular xylem 9 (irx9) mutant of Arabidopsis. The analysis revealed a decrease in the abundance of xylan in the mutant, indicating that the IRX9 gene, which encodes a putative family 43 glycosyltransferase, is required for xylan synthesis.

Arabidopsis↗
PubMed2003

Allofustis seminis gen. nov., sp. nov., a novel Gram-positive, catalase-negative, rod-shaped bacterium from pig semen.

An unknown Gram-positive, catalase-negative, facultatively anaerobic, non-spore-forming, rod-shaped bacterium originating from semen of a pig was characterized using phenotypic, molecular chemical and molecular phylogenetic methods. Chemical studies revealed the presence of a directly cross-linked cell wall murein based on L-lysine and a DNA G + C content of 39 mol%. Comparative 16S rRNA gene sequencing showed that the unidentified rod-shaped organism formed a hitherto unknown subline related, albeit loosely, to Alkalibacterium olivapovliticus, Alloiococcus otitis, Dolosigranulum pigrum and related organisms, in the low-G + C-content Gram-positive bacteria. However, sequence divergence values of > 11% from these recognized taxa clearly indicated that the novel bacterium represents a separate genus. Based on phenotypic and phylogenetic considerations, it is proposed that the unknown bacterium from pig semen be classified as a new genus and species, Allofustis seminis gen. nov., sp. nov. The type strain is strain 01-570-1(T) (= CCUG 45438(T) = CIP 107425(T)).

Animals↗
PubMed1997

Relationship of Endo-[beta]-D-Mannanase Activity and Cell Wall Hydrolysis in Tomato Endosperm to Germination Rates.

The endosperm tissue enclosing the radicle tip (endosperm cap) governs radicle emergence in tomato (Lycopersicon esculentum Mill.) seeds. Weakening of the endosperm cap has been attributed to hydrolysis of its mannan-rich cell walls by endo-[beta]-D-mannanase. To test this hypothesis, we measured mannanase activity in tomato endosperm caps from seeds allowed to imbibe under conditions of varying germination rates. Over a range of suboptimal temperatures, mannanase activity prior to radicle emergence increased in accordance with accumulated thermal time. Reduced water potential delayed or prevented radicle emergence but enhanced mannanase activity in the endosperm caps. Abscisic acid did not prevent the initial increase in mannanase activity, although radicle emergence was markedly delayed. Sugar composition and percent mannose (Man) content of endosperm cap cell walls did not change prior to radicle emergence under any condition. Man, glucose, and other sugars were released into the incubation solution by endosperm caps isolated from intact seeds during imbibition. Pregerminative release of Man was suppressed and the release of glucose was enhanced when seeds were incubated in osmoticum or abscisic acid; the opposite occurred in the presence of gibberellin. Thus, whereas sugar release patterns were sensitive to environmental and hormonal factors affecting germination, neither assayable endo-[beta]-D-mannanase activity nor changes in cell wall sugar composition of endosperm caps correlated well with tomato seed germination rates under all conditions.

Journal Article↗
PubMed2006

Bacillus foraminis sp. nov., isolated from a non-saline alkaline groundwater.

A low-G+C-content Gram-positive bacterium, designated CV53T, phylogenetically related to species of the genus Bacillus, was isolated from a highly alkaline non-saline groundwater environment (pH 11.4). This organism comprised rod-shaped cells, was aerobic, did not display spore formation, was catalase- and oxidase-negative, had an optimum growth temperature of 40 degrees C and had an optimum pH of approximately 7.0-8.5. Optimal growth was observed in the absence of NaCl, but growth did occur at NaCl concentrations up to 3.0%. The strain possessed an A1gamma-type peptidoglycan cell wall and the major respiratory quinone was MK-7. The predominant fatty acids were anteiso-C15:0, iso-C15:0 and anteiso-C17:0. The G+C content of the DNA was 43.1 mol%. Phylogenetic analyses of the 16S rRNA gene sequence revealed that the novel isolate is closely related to the type strain of Bacillus jeotgali, forming a coherent cluster supported by bootstrap analysis at a confidence level of 90%. The pairwise similarity of the 16S rRNA gene sequences of the two strains is 97.7%. On the basis of the phylogenetic analyses and the distinct phenotypic characteristics, strain CV53T represents a novel species within the genus Bacillus, for which we propose the name Bacillus foraminis sp. nov. The type strain is CV53T (=LMG 23174T=CIP 108889T).

Aerobiosis↗
PubMed1983

Growth of Propionibacterium acnes strains on semisynthetic medium; antigenic polysaccharide production.

A semisynthetic medium, containing yeast extract as the only non defined component and glucose, glycerol, Tween 80 and mineral salts, has been developed to grow the strains of Propionibacterium acnes Beck 2037, Gerrath 2038 and Vogel 2039, at a rate comparable to that of complex media. An average of 10(12) cells per 1 (equivalent to approximately 1.5 g/l dry weight) was usually achieved. These yields are appropriated for biochemical and immunological studies, e.g. cell wall preparation, polysaccharides isolation, etc. In this work, some properties of the cell walls (sugar and amino acid composition) and the antigenic polysaccharides (neutral and amino sugar components) are described.

Amino Acids↗
PubMed2001

Comparison of the hydrophobic properties of Candida albicans and Candida dubliniensis.

Although Candida dubliniensis is a close genetic relative of Candida albicans, it colonizes and infects fewer sites. Nearly all instances of candidiasis caused by C. dubliniensis are restricted to the oral cavity. As cell surface hydrophobicity (CSH) influences virulence of C. albicans, CSH properties of C. dubliniensis were investigated and compared to C. albicans. Growth temperature is one factor which affects the CSH status of stationary-phase C. albicans. However, C. dubliniensis, similar to other pathogenic non-albicans species of Candida, was hydrophobic regardless of growth temperature. For all Candida species tested in this study (C. albicans, C. dubliniensis, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis), CSH status correlated with coaggregation with the anaerobic oral bacterium Fusobacterium nucleatum. Previous studies have shown that CSH status of C. albicans involves multiple surface proteins and surface protein N-glycans. The hydrophobic surface glycoprotein CAgp38 appears to be expressed by C. albicans constitutively regardless of growth temperature and medium. C. dubliniensis expresses a 38-kDa protein that cross-reacts with the anti-CAgp38 monoclonal antibody; however, expression of the protein was growth medium and growth temperature dependent. The anti-CAgp38 monoclonal antibody has been shown to inhibit adhesion of C. albicans to extracellular matrix proteins and to vascular endothelial cells. Since protein glycosylation influences the CSH status of C. albicans, we compared the cell wall mannoprotein content and composition between C. albicans and C. dubliniensis. Similar bulk compositional levels of hexose, phosphate, and protein in their N-glycans were determined. However, a component of the C. albicans N-glycan, acid-labile phosphooligomannoside, is expressed much less or negligibly by C. dubliniensis, and when present, the oligomannosides are predominantly less than five mannose residues in length. In addition, the acid-labile phosphooligomannoside profiles varied among the three strains of C. dubliniensis we tested, indicating the N-glycan of C. dubliniensis differs from C. albicans. For C. albicans, the acid-labile phosphooligomannoside influences virulence and surface fibrillar conformation, which affects exposure of hydrophobic surface proteins. Given the combined role in C. albicans of expression of specific surface hydrophobic proteins in pathogenesis and of surface protein glycosylation on exposure of the proteins, the lack of these virulence-associated CSH entities in C. dubliniensis could contribute to its limited ability to cause disseminated infections.

Blotting, Western↗