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PubMedDate not supplied

[Review of the systematic position of Actinomyces orientalis (Pittenger et Brigham) Krass. 1970 and its reclassification as Proactinomyces orientalis (Pittenger et Brigham) comb. nov].

The micromorphology, growth cycle, chemical composition of the cell walls, and the susceptibility to lysozyme and specific phages were studied with the culture of Actinomyces orientalis RIA-1074. It is seggested on the basis of these studied to transfer the culture from the Actinomyces genus to the Proactinomyces genus and to rename it Proactinomyces orientalis (Pittinger et Brigham) comb. nov.

Actinomyces↗
PubMed1975

[Cellular lysis and dissociative phase of the genus Bacillus].

The sensitivity of the dissociative variants "R", "RS" and "S" of the spore-forming bacilli to some lytic agents (lysozyme, sodium lauryl sulphate, lipase, trypsin and some of their associations) has been studied. The research has been carried out on 32 strains: 14 "R", 14 "RS" and 4 "S" of different species of the genus Bacillus. The results have shown that the sensitivity to the studied lytic agents is strictly correlated, not to the species, but to the dissociative phases: these results are in accordance with those obtained in previous researches, carried out by the same Authors, on other characters, both morphological and biological, of the same variants. Thus, also through this way, it is possible to reach the conclusion that within this genus, there is more similarity among the different species of the same dissociative phase than among different dissociative variants of the same species. The results obtained in the present study allow to advance hypothesis, based also on the data of the literature, about the composition of the cell walls of the three above mentioned dissociative variants of the strains belonging to the genus Bacillus.

Bacillus↗
PubMedDate not supplied

[Heterogeneity of the genus Actinomadura Lechevalier a. Lechevalier].

Studies of the morphology of Actinomadura spp. have shown that the genus comprises several morphological types of actinomycetes which differ by the presence and structure of the sporophores on the aerial and substrate mycelium. The actinomycetes differ also by the fatty acid composition of lipids in the mycelium, and can be subdivided into three groups: (1) fatty acids with a straight chain prevail; (2) fatty acids with branched chains of the iso- and anteiso structure predominate; and (3) fatty acids with straight and branched chains are contained in almost equal amounts. Therefore the genus separated on the basis of differences in the composition of the cell wall was heterogeneous according to the properties used in the taxonomy of the actinomycetes at the level of genus. These data prove that morphological properties have to be taken into account in the taxonomy of the actinomycetes.

Actinomycetaceae↗
PubMed2002

[Mycobacterium tuberculosis and its host].

Human beings are the only hosts of Mycobacterium tuberculosis. Owing to a peculiar architecture and composition of the cell wall, M. tuberculosis presents characteristic properties (acid fastness, high hydrophobicity). Molecules, proteins and polysaccharides, present on the cell surface play a key role in the rapid bacterial phagocytosis by macrophages. M. tuberculosis is able to inhibit the intracellular bactericidal mechanisms. Potent thymodependent immune responses control bactericial growth through inflammatory reactions.

Humans↗
PubMed1985

[High-molecular antigenic complex of the pneumococcus: its properties].

The study of an antigenic preparation isolated from pneumococci, serotype 3, by the method of alkaline hydrolysis has revealed that the preparation contains a high-molecular complex protein-polysaccharide composition of the cell wall of this microorganism. The preparation contains at least two immunologically active components: the type-specific polysaccharide of serotype 3 pneumococcus and a nonspecific protein component. This antigenic preparation is capable of the formation of immunological memory in mice and protecting them from experimental challenge with pneumococci of homologous and heterologous serotypes.

Animals↗
PubMed1979

Loss of virulence of revertants from Staphylococcus aureus L-phase variants in comparison with the parent strain.

The L-forms of the Klecha 155 strain were induced in vitro by methicillin. After reversion, the strains were tested for 19 biochemical features and for susceptibility to penicillin, ampicillin and methicillin. Two reverted strains were less virulent for mice than the parent strain. It is concluded that the decrease in virulence of reverted Staph. aureus strains is correlated with changes in the chemical structure and composition of the cell wall after reversion from the L-phase variants.

Ampicillin↗
PubMedDate not supplied

[Transfer of species of the genus Actinomadura Lechevalier et Lechevalier 1970 to the genus Nocardiopsis Meyer 1976].

The type cultures of four Actinomadura species (A. africana, A. coeruleofusca, A. flava, A. longispora) were studied and compared with the type culture belonging to the genus Nocardiopsis. In their morphological properties and in the composition of the cell wall, these cultures were shown to be closer to the genus Nocardiopsis Meyer 1976 rather than to the genus Actinomadura Lechevalier et Lechevalier 1970. Basing on these data, the species have been transferred to the genus Nocardiopsis.

Actinomycetales↗
PubMed1976

[Morphological and physiological peculiarities of spherical (11r) mutants of Escherichia coli K12].

A study was made of morphology, character and the rate of reproduction in 8 11r mutants obtained from Hfr and F--strains of E. coli K12 under the effect of N-nitroso-N-methylurea. The capacity of 11r mutants to realize several types of reproduction: transverse division, budding, asymmetrical division, and formation of granular forms was demonstrated. The rate of cell division, total DNA, RNA and protein synthesis were lower at the phase of rest and early exponential growth phase in the 11r mutants than in the parent cultures. Hyperosmotic conditions created by various stabilizers, media with increased viscosity and of different chemical composition, and also cell wall hydrolysate and their precursors failed to stimulate the 11r mutant reversion. A change of morphology, but not the reversion was seen on the media containing glycine and penicillin. Reversion was spontaneous with low frequency; it was observed in induction of inverse mutations with N-nitroso-N-methylurea.

Bacterial Proteins↗
PubMed1997

[Rapid identification of four bacterial species by proton magnetic resonance spectroscopy].

In the present study, we applied proton nuclear magnetic resonance (1H NMR) spectroscopy to distinguish between four bacterial species: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Because of differences in the composition of their cell wall and cytoplasmic constituents, individual bacterial species exhibited characteristic spectra except for K. pneumoniae. Reproducibility was satisfactory in the quantitative studies for chemical shift, intensity of signal and integrated intensity. The turnaround time of the test was only about 40 minutes. 1H NMR could be a new powerful tool for strain identification.

Escherichia coli↗
PubMed2001

Molecular organization of the cell wall of Candida albicans.

We have recently presented a molecular model of the cell wall of Saccharomyces cerevisiae. Here we discuss the evidence that a similar model is also valid for Candida albicans. We further discuss how cell-wall proteins are linked to the skeletal layer of the wall, and their potential functions. We emphasize that the composition and structure of the cell wall depends on growth conditions. Finally, cell-wall damage seems to activate a salvage mechanism resulting in restructuring of the cell wall.

Candida albicans↗
PubMed1997

Anionic polymers in cell walls of gram-positive bacteria.

Information on the prevalence, compositions, and structures of anionic carbohydrate-containing polymers of cell walls of Gram-positive bacteria is summarized. The data suggest that these polymers are important for normal functioning of bacterial cells and require further studies. Structural data on teichoic acids found in the literature published over the last few years are discussed. This is a very diverse class of polymers whose structure-specific pathways of degradation were studied and NMR spectra were examined. Unique comprehensive tables of 13C-NMR spectroscopic data (mainly obtained by the authors) on these polymers are given in the Appendix. Other tables summarize data on teichuronic acids, sugar-phosphate polymers, acid polysaccharides, and structural variants of bonds between acid polysaccharides and peptidoglycans known from the literature. Functions of anionic polymers and their possible chemotaxonomic applications are discussed.

Anions↗
PubMed2003

Streptomonospora alba sp. nov., a novel halophilic actinomycete, and emended description of the genus Streptomonospora Cui et al. 2001.

A halophilic actinomycete, strain YIM 90003(T), was isolated from a soil sample collected from Xinjiang Province, China, by using starch-casein agar with a salt concentration of 20 % (w/v), pH 7.0. The strain grew well on most media tested. No diffusible pigment was produced. Aerial mycelium and substrate mycelium were well developed on most media. The aerial mycelium formed short spore chains, bearing non-motile, straight to flexuous spores with wrinkled surfaces. The cell walls of strain YIM 90003(T) contained meso-diaminopimelic acid as the diagnostic diamino acid. Cell-wall hydrolysates contained galactose and arabinose. Menaquinone composition varied with the medium used for cell cultivation; on glucose-yeast extract medium supplemented with 10 % NaCl, the major menaquinone was MK-9(H(4)), while, on vitamin-enriched ISP 2 medium, the major menaquinones were MK-10(H(2)), MK-9(H(8)) and MK-10(H(4)). Phospholipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, diphosphatidyl glycerol, methylphosphatidylethanolamine, phosphatidylserine, phosphatidylcholine and an unidentified phospholipid. 16S rRNA gene sequence analysis showed Streptomonospora salina as the closest phylogenetic neighbour. On the basis of these analyses, strain YIM 90003(T) is a member of the genus Streptomonospora, though its properties do not match the generic description fully with respect to the menaquinone composition and peptidoglycan amino acid. Analyses of mechanically disrupted cell walls of the type species, Streptomonospora salina DSM 44593(T), and strain YIM 90003(T), purified by tryptic digestion and subsequent SDS treatment, revealed the exclusive presence of meso-diaminopimelic acid as the diagnostic diamino acid of peptidoglycan. Thus, the genus description of Streptomonospora, indicating the presence of several amino acids usually not found in the peptidoglycan moiety, is therefore emended. DNA-DNA hybridization and comparison of physiological and chemotaxonomic characteristics demonstrated strain YIM 90003(T) to be different from Streptomonospora salina. The name Streptomonospora alba sp. nov. is proposed, with strain YIM 90003(T) (=CCTCC AA001013(T)=DSM 44588(T)) as the type strain.

Actinomycetales↗
PubMed2002

Dynamic changes in cell wall polysaccharides during wheat seedling development.

Changes in arabinoxylan content and composition during development of wheat seedlings were investigated. The cell walls isolated from the seedlings showed an increasing content of arabinoxylan during development, which could be correlated to increased activity of xylan synthase and arabinoxylan arabinosyltransferase. Arabinoxylan changed from initially having a high degree of arabinose substitution to a much lower degree of substitution. beta-Glucan was present in the walls at the early stages of development, but was actively degraded after day 4. Increased deposition of arabinoxylan did not take place until beta-glucan had been fully degraded. Ferulic and p-coumaric acid esters were present at all points but increased significantly from day 3 to 6, where lignification began. Ferulic acid dimers did not appear in the cell wall until day three and the different ferulic acid dimers varied in the course of accumulation. The ratio of ferulic acid dimers to free ferulic acid was maximal at the time when the wall had been depleted for beta-glucan, which had not yet been fully replaced by arabinoxylan. This pattern suggests a role for ferulic acid dimers in stabilizing the wall during the transition from a flexible to a more rigid structure. To investigate if the same changes could be observed within a single seedling, 7 day old seedlings were divided into four sections and the walls were analyzed. Some of the changes observed during the seedling development could also be observed within a single seedling, when analyzing the segments from the elongation zone at the base to the top of the leaf. However, the expanding region of older seedlings was much richer in hydroxycinnamates than the expanding region of younger seedlings. Diferulic acids are stabilizing the wall in the transition phase from an expanding to a mature wall. This transition can take place in different manners depending on the cell and tissue type.

Cell Wall↗
PubMed2026

Elemental composition, structure and amount of contact between Xanthoria parietina symbionts.

As prominent examples for symbiotic interactions, the major part of lichens is built up by two different organisms, a photosynthetically active alga (photobiont) and a heterotrophic fungus (mycobiont). Given the hydrophobic coating of lichen symbionts in the lichen thallus by hydrophobins, the area of direct cell cell contact is of prime importance for the transfer of nutrients and signalling compounds between the symbionts. Genomic analyses reported cell wall remodelling during symbiont interaction. However, no detailed investigation of lichen symbiont interaction zone is available so far. Using Energy-dispersive X-ray spectroscopy (EDS), we show that elemental composition of both symbiont cell walls differs when in contact to the symbiont as opposed to those cell wall areas without contact. Both, nitrogen and sulfur content of cell walls, differ significantly in areas of symbiont cell contacts as compared to non-contact zones. NanoCT imaging revealed that about one fourth of the photosymbiont cell wall is in contact to mycobiont hyphae, and fungal cells have a significantly increased volume if in contact to photobiont cells. We provide a sub µm 3D model of the lichen Xanthoria parietina using nanoCT imaging to foster understanding of the symbiont interaction zone.

Symbiosis↗
PubMed2004

Is apoptosis of vascular smooth muscle cells involved in the development of Takayasu arteritis? Suggestions from a case report.

OBJECTIVES: We report a female patient suffering from Takayasu arteritis (TA) who underwent surgical revascularization. METHODS: By studying specimens obtained at surgery, we evaluated the cell composition of the arterial wall, along with the maturation pattern of vascular smooth muscle cells (VSMC) during the active phase of TA. Using TUNEL, we detected apoptotic cells within the tunica media. RESULTS: The highest percentage of apoptotic cells was found in areas where inflammatory infiltrate was present and the medial structure was more or less damaged. Apoptotic cells were also found in structurally preserved areas, where VSMC but not inflammatory cells were present. CONCLUSIONS: Apoptosis involved not only inflammatory cells but also VSMC, particularly those of the immature type. We hypothesize a role for VSMC apoptosis in the development of TA.

Adult↗
PubMedDate not supplied

Fluorescence and infrared spectrometric study of cell walls from Candida, kluyveromyces, Rhodotorula and schizosaccharomyces yeasts in relation with their chemical composition.

Composition, level, and arrangement of the structural polysaccharides determine biophysical properties of fungal cell walls. A small amount of a beta(1-->4) linear homopolymer of GlcNAc in the cell wall forms chitin. To study the components of the cell walls and to estimate the quantity of chitin for different strains, two spectroscopic methods were applied. Because chemical and enzymatic methods are destructive, long, and complex, fluorescence and infrared (IR) spectroscopies were applied on cell walls and on chitin enriched fractions. The results were compared to chemical assays. IR spectra allow identifying the structural types of polysaccharides in yeast walls. Fluorescence spectroscopy was not appropriated for a full and accurate quantitative determination of the polymers but revealed level variations similar to results obtained by chemical analytical methods. The infrared spectra, using a chemometric approach (PLS1), allowed a fairly good estimation of chitin in enriched fractions with respect to the chemical assays.

Candida↗
PubMed2006

Glycoprotein hypersecretion alters the cell wall in Trichoderma reesei strains expressing the Saccharomyces cerevisiae dolichylphosphate mannose synthase gene.

Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increased amount of N-acetylglucosamine, suggesting an increase in chitin content. Calcofluor white staining followed by fluorescence microscopy indicated changes in chitin distribution. Moreover, we also observed a decreased concentration of mannose and alkali-soluble beta-(1,6) glucan. A comparison of protein secretion from protoplasts with that from mycelia showed that the cell wall created a barrier for secretion in the DPM1 transformants. We also discuss the relationships between the observed changes in the cell wall, increased protein glycosylation, and the greater secretory capacity of T. reesei strains expressing the yeast DPM1 gene.

Biotechnology↗