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PubMed2006

Deposition of cell wall polysaccharides in wheat endosperm during grain development: Fourier transform-infrared microspectroscopy study.

The time course and pattern deposition of the cell wall polysaccharides in the starchy endosperm of wheat (Triticum aestivum cv. Recital) during grain development was studied using Fourier transform infrared microspectroscopy (micro-FTIR). Three stages of grain development identified as key stages for cell wall construction were retained as follows: the end cellularization, the beginning of cell differentiation, and the beginning of maturation. Micro-FTIR revealed that beta-(1-->3),(1-->4) glucans and arabinoglactan proteins are the main cell wall components of endosperm at the end of the cellularization stage, whereas arabinoxylans (AX) appeared only at the cell differentiation stage. Past the differentiation stage, FTIR spectra were dominated by AX features. Cell walls at the beginning of cell differentiation and at endosperm maturation could be distinguished by spectral features that were ascribed to AX substitution. AX appeared more substituted at the beginning of cell differentiation. Moreover, a difference in the degree of AX substitution was found between peripheral and central parts of the grain at the cell differentiation stage; AX in central cells was less substituted. Thus, dramatic changes in endosperm cell wall composition were detected during wheat grain development with respect to both the relative occurrence of individual constituents and the fine structure of the AX.

Cell Wall↗
PubMed2001

Enhancement of beta-sitosterol transformation in Mycobacterium vaccae with increased cell wall permeability.

Mycobacterium vaccae exposed to compounds which are known to disorganise the cell wall composition and architecture (protamine, glycine) showed increased specific activity in beta-sitosterol biotransformation to androstene derivatives, intennediates in the production of most medical steroids. GC/MS analysis of free lipid fatty acids revealed higher content of unsaturated compounds, mainly C16:1 and C18:1 in protamine- and glycine-treated cells than that in control cells, which seems to change the permeability features of the cell wall barrier, facilitating hydrophobic beta-sitosterol diffusion.

Androstadienes↗
PubMed2004

Penicillin-binding protein 2 is essential for expression of high-level vancomycin resistance and cell wall synthesis in vancomycin-resistant Staphylococcus aureus carrying the enterococcal vanA gene complex.

A combination of biochemical and genetic experiments were performed in order to better understand the mechanism of expression of high-level vancomycin resistance in Staphylococcus aureus. The transcription of pbp2 of the highly vancomycin- and oxacillin-resistant strain COLVA200 and its mutant derivative with inactivated mecA were put under the control of an inducible promoter, and the dependence of oxacillin and vancomycin resistance and cell wall composition on the concentration of the isopropyl-beta-D-thiogalactopyranoside inducer was determined. The results indicate that mecA--the genetic determinant of oxacillin resistance--while essential for oxacillin resistance, is not involved with the expression of vancomycin resistance. Penicillin binding protein 2A, the protein product of mecA, appears to be unable to utilize the depsipeptide cell wall precursor produced in the vancomycin-resistant cells for transpeptidation. The key penicillin binding protein essential for vancomycin resistance and for the synthesis of the abnormally structured cell walls characteristic of vancomycin-resistant S. aureus (A. Severin, K. Tabei, F. Tenover, M. Chung, N. Clarke, and A. Tomasz, J. Biol. Chem. 279:3398-3407, 2004) is penicillin binding protein 2.

Bacterial Proteins↗
PubMed2004

Taxonomic discrimination of flowering plants by multivariate analysis of Fourier transform infrared spectroscopy data.

Fourier transform infrared spectroscopy (FTIR) provides biochemical profiles containing overlapping signals from a majority of the compounds that are present when whole cells are analyzed. Leaf samples of seven higher plant species and varieties were subjected to FTIR to determine whether plants can be discriminated phylogenetically on the basis of biochemical profiles. A hierarchical dendrogram based on principal component analysis (PCA) of FTIR data showed relationships between plants that were in agreement with known plant taxonomy. Genetic programming (GP) analysis determined the top three to five biomarkers from FTIR data that discriminated plants at each hierarchical level of the dendrogram. Most biomarkers determined by GP analysis at each hierarchical level were specific to the carbohydrate fingerprint region (1,200-800 cm(-1)) of the FTIR spectrum. Our results indicate that differences in cell-wall composition and structure can provide the basis for chemotaxonomy of flowering plants.

Biomarkers↗
PubMed1986

Inhibition by pyrazinamide of tubercle bacilli within cultured human macrophages.

Pyrazinamide (PZA) is a unique antituberculosis drug because it is effective in vivo but not in mediums commonly used to culture tubercle bacilli. Consequently, it was employed to test the validity of an in vitro macrophage model of human tuberculosis for value as a correlate of clinical events. The drug was as active in the macrophage model as it was clinically, inhibiting virulent tubercle bacilli at concentrations at 20 micrograms/ml or higher. By contrast, it was ineffective in 7H9 bacteriologic culture medium, even at concentrations as high as 2,560 micrograms/ml. It could be either bacteriostatic or bactericidal against intramacrophage tubercle bacilli, depending on its concentration, the donor of the macrophages, and the length of exposure of the infected macrophages to the drug. The data presented suggest that the clinical effectiveness of PZA is determined by a complicated self-modulating sequence of interactions between it, tubercle bacilli, and host macrophages. Specific evidence was found that tubercle bacilli may replicate within human macrophages in non-acid-fast form, thus indicating that colony-forming unit counts are inherently more accurate than acid-fast bacilli counts in these experiments, and also suggesting that important changes in bacillary cell wall composition may occur among tubercle bacilli within infected human macrophages.

Adult↗
PubMed1978

Histoplasma capsulatum: chemical variability of the yeast cell wall.

Four strains of Histoplasma capsulatum were analyzed to observe any variations in their cell wall composition. Strain G-184B produced the same amount of sugars reported by Domer (2) although qualitative analyses agreed with Kanetsuna's report (4) as far as the presence of glucose, galactose, and mannose was concerned. Our results agree with previous reports in classifying H. capsulatum into chemotypes I and II, the latter having more alpha-glucan in its cell wall. A decrease in the amount of fraction 2 (alpha-glucan) of strain G-184B was observed when the strain was subcultured in vitro for many years, an effect similar to that reported for Paracoccidioides brasiliensis (12, 13).

Cell Wall↗
PubMed2003

Maize stem tissues: ferulate deposition in developing internode cell walls.

It has been hypothesized that ferulates are only deposited in the primary cell wall of grasses. To test this hypothesis, the fourth elongating, above-ground internode of maize (Zea mays l.) was sampled from three maize hybrids throughout development. Cell wall composition was determined by the Uppsala Dietary Fibre method. Ester- and ether-linked ferulates were determined by HPLC analysis of ferulic acid released from the internodes by low and high temperature alkaline treatments. Internode length increased from 9 to 152 mm over 96 days of growth, with elongation being complete in the first 12 days. More than half of the cell wall material in the maize internodes accumulated after elongation had ended. Deposition of cell wall material appeared to reach its maximum extent 40 days after sampling began, well before physiological maturity of the maize plants. Galactose and arabinose began to accumulate early in cell wall development which was presumed to be associated with primary wall growth during internode elongation. The major secondary wall constituents (analyzed as glucose, xylose, and Klason lignin) did not begin to accumulate rapidly until shortly before internode elongation ended. Ferulate ester deposition began before ferulate ethers were observed in the cell wall, but both forms of ferulate continued to accumulate in secondary cell walls, long after internode elongation had ceased. These data clearly show that contrary to the hypothesis, ferulate deposition was not restricted to the primary wall and that active lignin/polysaccharide cross-linking mediated by ferulates occurs in the secondary wall.

Cell Wall↗
PubMed1984

Identification of Brevibacterium from clinical sources.

Coryneform bacteria of the genus Brevibacterium occur on the normal skin surface, but reports of human infection with this genus are lacking. A number of cultures of coryneform bacteria sent to the National Collection of Type Cultures for identification have been identified as Brevibacterium spp on the basis of their cell wall composition and ability to produce methane-thiol from L-methionine. We describe a rapid method for the detection of methane-thiol and confirmatory tests which differentiate Brevibacterium from morphologically similar genera.

Bacteriological Techniques↗
PubMed1992

Dimorphism in Benjaminiella poitrasii: cell wall chemistry of parent and two stable yeast mutants.

In the dimorphic zygomycetous fungus Benjaminiella poitrasii, the cell wall compositions of mycelial phase (M), yeast phase (Y) and its yeast form mutants (Y-2 and Y-5) were studied. Chitosan was abundant in M-phase (26.6%) whereas lesser amounts were present in Y-phase (17.3%) and in mutants Y-2 (19.6%) or Y-5 (17.3%). Although chitin was present as a smaller fraction of the total glucosaminoglycan in each of different cell wall preparations, it was almost 3 times more prevalent in M-phase than the Y-phase cells. Cross-linking studies among the various cell wall components in B. poitrasii, suggest linkages among mannans and proteins and glucans and glucosaminoglycans.

Amino Acids↗
PubMedDate not supplied

[Quantitative determination of the protein and carbohydrate polymers in the cell wall of Streptococcus group A].

The content of protein and carbohydrate polymers was estimated in the cell wall of Streptococcus, group A, type 29. A method was developed for analysing peptidoglycane in a polysaccharide-peptidoglycane complex after the prior oxidation by sodium periodate. It was found that the cell wall peptidoglycane bears two carbohydrate and three amino acid residues, i. e. N-acetylglucosamin, muramic acid, glutamic acid, alanine and lysine, in the ratio 1:1:1:4:1, respectively. The data on the cell wall composition prior to and after its oxidation with sodium periodate are given, and the ratio between the main structural components is determined: proteins (60% mol), polysaccharide (23% mol), peptidoglycane (17% mol).

Bacterial Proteins↗
PubMed1968

Penicillin-resistant variants of pneumococci.

All of the 74 strains of pneumococci isolated from human infections from 1963 to 1964 proved to be uniformly and highly susceptible to penicillin. Of these strains, 15 were identified by capsule-swelling reactions and were submitted to serial transfer in the presence of increasing concentrations of penicillin. Highly penicillin-resistant mutants were selected from 14 of the 15 strains, whereas one strain was moderately resistant. Of these mutants, 11 could still react with specific antiserum, and all of the mutants could be identified by fermentation reactions and optochin inhibition. The in vitro development of penicillin resistance in these mutants did not result in a change in cell-wall composition sufficient to diminish bile solubility. The possibility of encountering rising penicillin resistance among pneumococci, as well as the possibility that such mutants may react atypically, should be kept in mind.

Antigens↗
PubMed2007

Neural network analyses of infrared spectra for classifying cell wall architectures.

About 10% of plant genomes are devoted to cell wall biogenesis. Our goal is to establish methodologies that identify and classify cell wall phenotypes of mutants on a genome-wide scale. Toward this goal, we have used a model system, the elongating maize (Zea mays) coleoptile system, in which cell wall changes are well characterized, to develop a paradigm for classification of a comprehensive range of cell wall architectures altered during development, by environmental perturbation, or by mutation. Dynamic changes in cell walls of etiolated maize coleoptiles, sampled at one-half-d intervals of growth, were analyzed by chemical and enzymatic assays and Fourier transform infrared spectroscopy. The primary walls of grasses are composed of cellulose microfibrils, glucuronoarabinoxylans, and mixed-linkage (1 --> 3),(1 --> 4)-beta-D-glucans, together with smaller amounts of glucomannans, xyloglucans, pectins, and a network of polyphenolic substances. During coleoptile development, changes in cell wall composition included a transient appearance of the (1 --> 3),(1 --> 4)-beta-D-glucans, a gradual loss of arabinose from glucuronoarabinoxylans, and an increase in the relative proportion of cellulose. Infrared spectra reflected these dynamic changes in composition. Although infrared spectra of walls from embryonic, elongating, and senescent coleoptiles were broadly discriminated from each other by exploratory principal components analysis, neural network algorithms (both genetic and Kohonen) could correctly classify infrared spectra from cell walls harvested from individuals differing at one-half-d interval of growth. We tested the predictive capabilities of the model with a maize inbred line, Wisconsin 22, and found it to be accurate in classifying cell walls representing developmental stage. The ability of artificial neural networks to classify infrared spectra from cell walls provides a means to identify many possible classes of cell wall phenotypes. This classification can be broadened to phenotypes resulting from mutations in genes encoding proteins for which a function is yet to be described.

Algorithms↗
PubMed2003

Efficient mechanical disruption of Lactobacillus helveticus, Lactococcus lactis and Propionibacterium freudenreichii by a new high-pressure homogenizer and recovery of intracellular aminotransferase activity.

Microbiological studies often involve bacterial cell fractionation, which is known to be difficult for Gram-positive as compared to Gram-negative bacteria. Our purpose was to test the breaking efficiency of a new high-pressure pilot homogenizer for three Gram-positive species involved in dairy technology and to assess the activity of an intracellular aminotransferase. Varied pressures (50, 100 and 200 MPa) were applied to concentrated bacterial suspensions (1.2 mg dry weight/ml) of Lactobacillus helveticus, Lactococcus lactis and Propionibacterium freudenreichii. Breaking efficiency was estimated by decreases in optical density at 650 nm, cellular dry weight and viability. The proteins released were quantified and the residual intracellular aminotransferase activity was estimated using leucine as substrate. One run at 50 MPa was sufficient to break 80% of lactobacilli cells whereas 200 MPa were required for the same efficiency for L. lactis and P. freudenreichii. Whatever the pressure, leucine aminotransferase activity was recovered in the supernatant after cell breaking. This new high-pressure pilot homogenizer can allow rapid (20 s/run), easy, continuous and highly efficient cell breaking for intracellular enzyme recovery or other purposes. As the species tested were not phylogenetically related, and had different morphologies and cell wall compositions, we conclude that most Gram-positive bacteria may be broken efficiently by this new device.

Bacteriological Techniques↗
PubMed1969

Identification of human strains of Actinomyces viscosus.

Catalase-positive actinomycetes which closely resemble the "hamster organism" described by Howell have been isolated from dental calculus and other human sources. These cultures could not be distinguished from the hamster strains on the basis of morphology, oxygen requirements, biochemical reactions, or cell wall composition. These human isolates have been classified with the hamster strains as Actinomyces viscosus. The strains from hamster and human sources fell into two serotypes. Serotype 1 contains the hamster strains plus one strain of unknown origin, whereas serotype 2 contains all of the human strains.

Actinomyces↗
PubMed1975

Sexual differentiation in Aspergillus nidulans: the requirement for manganese and its effect on alpha-1,3 glucan synthesis and degradation.

Aspergillus nidulans was grown on media with added amounts of manganese ranging from 0--2.5 muM. Manganese deficiency prevented cleistothecium development, although good vegetative growth was retained. Subsequent analysis of the mycelium produced under Mn2+ deficient growth revealed that alpha-1,3 glucan, the man carbon and energy source for fructification, was virtually absent from the cell wall. Several enzymes related to cell wall composition were investigated. Beta-1,3 glucanase, and very remarkably, alpha-1,3 glucanase reached about the same activity on the Mn2+ deficient and sufficient media, but amylase and protease were about 60 and 75% lower respectively on the Mn2+ deficient media and the correlation of these findings is discussed.

Amylases↗
PubMed2002

Efficient isolation of total RNA from antibiotic-producing bacterium Amycolatopsis mediterranei.

RNA extraction from antibiotic-producing actinomycetes can be a difficult and time-consuming process due to their special peptidoglycans cell wall composition and the short life of RNA. Hence, the rapidity of cellular lysis and complete inhibition of RNase are of particular importance for isolating intact RNA of high quality. The genus of Amycolatopsis mediterranei produces many clinically important antibiotics, such as rifamycin and vancomycin; however, the available methods for bacterial RNA isolation did not work very well with this genus. In this report, we described a new method for RNA isolation using the combination of LiCl, urea and guanidinium thiocyanate to disrupt the cell wall of Amycolatopsis. Compared with earlier published RNA isolation methods, the method gave higher yields of pure and intact RNA. About 1 microg total RNA free of DNA contamination can be obtained from 1 mg wet weight of A. mediterranei. The integrity of the RNA was demonstrated by formaldehyde agarose gel electrophoresis and Northern blot analyses.

Actinomycetales↗
PubMedDate not supplied

[Systematic position of Streptomyces luteofluorescens].

On the basis of the cell wall composition (the presence of meso-diaminopimelic acid and madurose sugar) and according to the morphological structure, Streptomyces luteofluorescens (type culture 719, ISP 5398) is transferred to Actinomadura genus. The organism is considered to be a new species of the Actinomadura genus -- Actinomadura luteofluorescens (Shinobu, 1962) Preobrazhenskaya et Lavrova, 1974, comb. nov.

Cell Wall↗