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K Augsten

Publications and source records attributed to K Augsten.

At least 19 recordsLinked to original sources
PubMed2001

The deletion of CaVPS34 in the human pathogenic yeast Candida albicans causes defects in vesicle-mediated protein sorting and nuclear segregation.

A Candida albicans null mutant of the phosphatidylinositol (PI) 3-kinase gene (CaVPS34) involved in virulence was examined by different microscopical techniques. We observed that vacuoles of the Cavps34 null mutant were considerably enlarged and electron-transparent. An interesting result obtained by transmission electron microscopy analysis of Cavps34 mutant cells was the aberrant patch-like accumulation of vesicles, which were localized in the periplasm close to the plasma membrane. We assume that the vesicles result from missorted prevacuolar compartments. In contrast to the accumulations of the specific endocytic dye FM4-64 in the vacuole membrane in C. albicans wild-type strains (ring staining pattern), the Cavps34 mutant strain showed a staining of punctuate structures, possibly multivesicular bodies (MVB), that are scattered all over the cell. This defect indicates a late block in endocytic vesicle transport. Measurement of the total activity of carboxypeptidase Y revealed significantly lower activity in Cavps34 mutant cells. This may indicate that carboxypeptidase Y is not properly activated as a result of mislocalization due to the lack of Vps34p. The deletion of the CaVPS34 gene caused disturbance of normal nuclear migration, which suggests that in the Cavps34 mutant the cell-size mediated control process of cell division is affected.

Acids↗
PubMed2001

Ornithinimicrobium humiphilum gen. nov., sp. nov., a novel soil actinomycete with L-ornithine in the peptidoglycan.

A Gram-positive bacterium originating from garden soil was taxonomically studied. Cells are non-motile, non-sporulating, irregular rods and cocci. The cell wall peptidoglycan contains L-ornithine as diagnostic diamino acid and an interpeptide bridge consisting of L-Orn<--L-Ala<--Gly<--D-Asp. The major menaquinone is MK-8(H4). 13-Methyl tetradecanoic acid and 14-methyl pentadecanoic acid are the predominant fatty acids. The polar lipids are phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, three unknown glycolipids and three unknown phospholipids. Mycolic acids are absent. The DNA G+C composition is 70 mol%. The acyl type of the glycan chain of peptidoglycan is acetyl. Glucose is the dominating whole cell sugar; arabinose, rhamnose and xylose are present in traces. Results of 16S rDNA sequence comparisons revealed that strain HKI 0124T represents a novel lineage within the suborder Micrococcineae of the order Actinomycetales adjacent to the recently described genus Ornithinicoccus. On the basis of the clearly pronounced morphological, physiological, chemotaxonomic and phylogenetic differences between strain HKI 0124T and all members of the suborder Micrococcineae, it is proposed to assign strain HKI 0124T to a new genus and species, Ornithinimicrobium humiphilum gen. nov., sp. nov. The type and only strain is HKI 0124T (= DSM 12362T = CIP 106634T).

Actinomycetales↗
PubMed1999

Ornithinicoccus hortensis gen. nov., sp. nov., a soil actinomycete which contains L-ornithine.

Two Gram-positive coccoid, non-motile bacteria with L-ornithine as diagnostic diamino acid of the peptidoglycan and an interpeptide bridge of L-Orn<--Gly(1,2)<--D-Glu were isolated from a sample of garden soil. The major menaquinone is MK-8(H4). 13-methyl and 12-methyl tetradecanoic acids are the predominant fatty acids. The polar lipids are phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine and two unknown phospholipids. Mycolic acids are absent. The DNA base composition is 72 mol% G + C. Recent comparative 16S rDNA studies revealed that strains HKI 0125T and HKI 0131 represent a novel lineage adjacent to the family Intrasporangiaceae of the order Actinomycetales but distinct from the previously described genera of this family. On the basis of the genotypic, chemotaxonomic, morphological and physiological characteristics of these two isolates it is proposed to classify HKI 0125T and HKI 0131 in a new genus and species for which the name Ornithinicoccus hortensis gen. nov., sp. nov. is proposed. The type strain is HKI 0125T (= DSM 12335T).

Actinomycetales↗
PubMed1999

Beutenbergia cavernae gen. nov., sp. nov., an L-lysine-containing actinomycete isolated from a cave.

Two aerobic, Gram-positive bacteria, strains HKI 0122T and HKI 0132, were isolated from a cave. Cells are not acid-fast, non-motile, non-spore-forming and exhibit a rod-coccus growth cycle. The cell wall peptidoglycan contains lysine in position 3 of the peptide subunit and an interpeptide bridge of L-Lys<--L-Glu. The major menaquinone is MK-8(H4), 13-methyl and 12-methyl tetradecanoic acids are the predominating fatty acids. The polar lipids consist of phosphatidylinositol, diphosphatidylglycerol and three unknown phospholipids. Mycolic acids are absent. The DNA base composition is 71 mol% G + C. Phylogenetic analysis revealed that strain HKI 0122T forms a novel taxon among the families and unassigned genera of the suborder Micrococcineae, within the order Actinomycetales. On the basis of the genotypic, chemotaxonomic, morphological and physiological characteristics of these two isolates it is proposed to assign strains HKI 0122T and HKI 0132 to a new genus and species for which the name Beutenbergia cavernae gen. nov., sp. nov. is proposed. The type strain is HKI 0122T (= DSM 12333T).

Actinomycetales↗
PubMed1997

Bogoriella caseilytica gen. nov., sp. nov., a new alkaliphilic actinomycete from a soda lake in Africa.

A new gram-positive, alkaliphilic, nonsporulating, rod-shaped bacterium is described. The organism was isolated from soda soil (Lake Bogoria, Kenya) and has the following characteristics. It is nonmotile, not acid fast, halotolerant, and microaerophilic, and optimal growth occurs at pH values between 9 and 10. The peptidoglycan type is of type A4 alpha, with lysine as the characteristic diamino acid and glutamic acid as a component of the interpeptide bridge. The major menaquinone is MK-8(H4). The polar lipids are phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, and an unknown phospholipid. 12-Methyltetradecanoic acid is the predominant fatty acid. The G + C content of the DNA is 70 mol%. The results of 16S ribosomal DNA sequence comparisons revealed that strain HKI 0088T represents a new lineage in the order Actinomycetales. Therefore, we concluded that strain HKI 0088T should be assigned to a new genus and species, for which we propose the name Bogoriella caseilytica gen. nov., sp. nov. The type strain and only strain of this genus and species is HKI 0088 (= DSM 11294).

Actinomycetaceae↗
PubMed1997

Demetria terragena gen. nov., sp. nov., a new genus of actinomycetes isolated from compost soil.

A novel actinomycete was isolated from compost soil and was studied taxonomically and phylogenetically. Cells of this organism were gram positive, not acid fast, nonmotile, nonsporulating, irregular coccoid to short rod shaped, and microaerophilic. The cell wall peptidoglycan contained lysine and was cross-linked via an L-Lys<--L-Ser<--D-Asp interpeptide bridge. The major menaquinone was MK-8(H4). The polar lipids were phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and two unknown phospholipids. Mycolic acids were absent. The cellular fatty acid profile was complex, with large amounts of saturated and monounsaturated straight-chain acids and smaller amounts of iso and anteiso branched-chain acids. The G+C content of the DNA was 66 mol%. Comparative 16S ribosomal DNA studies revealed that strain HKI 0089T represents a novel lineage within Actinobacteria (32) distinct from all previously described genera and most closely related to members of the genera Kytococcus, Dermacoccus, and Dermatophilus of the family Dermatophilaceae. On the basis of our results, we suggest that strain HKI 0089 should be classified in a new genus and species, for which we propose the name Demetria terragena. The type strain and the only strain of the genus and species is HKI 0089 (DSM 11295).

Actinomycetaceae↗
PubMed1996

Localization of G-proteins in macrophages and E. coli during phagocytosis.

Heterotrimeric GTP-binding proteins (G-proteins) have been shown to play an important role in cellular signalling. However, G-protein involvement in the intracellular spreading of bacterial pathogens is still poorly understood. In this study, antibodies, that recognize G-protein alpha-subunits (anti-G alpha), were used to investigate the localization of G-proteins in the macrophage-like cell line P388D1 and E. coli, also in their L-forms, during phagocytosis. In E. coli, anti-G alpha-binding sites were detected preferably in the cell wall and septa of the whole bacterial forms as well as in the cytoplasm of L-forms. Western blotting of bacterial lysates demonstrated protein bands with positive immunoreaction to antibodies against Gs alpha, Gi alpha, and Gcommon alpha with a higher affinity to the antibody against Gs alpha. Immunoreaction with the anti-Gs alpha-antibody was markedly higher in pathogenic strains of E. coli. Because of the conserved structure in all GTP-binding proteins which seem to derive from a single primordial protein involved in signal transduction mechanisms, it is reasonable to assume that some anti-Ga-positive proteins in E. coli might be related to G-proteins of higher organisms. A putative candidate for bacterial G-proteins seems to be a 36 kDa protein. Enhancement in G-protein immunostaining in the cytoplasm of macrophages around the internalized bacteria testifies to the involvement of G-proteins in mediation of endocytosis responses of phagocytes.

Animals↗
PubMed1992

In vivo changes of heterogeneity of mouse peritoneal macrophages induced by cis-diamminedichloroplatinum (II) (cis-DDP) and related platinum compounds.

The s.c. injection of cis-DDP into ABD2F1 mice (8 mg/kg b.m.) resulted in alterations of size and surface structure of peritoneal macrophages (PM) and in a reduction of the mean number of Concanavalin A (ConA) binding sites of PM. The PM population of control mice which received physiological saline only consisted of 2 subgroups with a higher and a lower mean ConA binding site number per cell. Contrarily, PM of cis-DDP-treated mice failed the subpopulation with higher ConA binding site number. A loss of this subpopulation was also found in mice treated with platinum salt K2PtCl4 or K2PtCl6. X-ray microanalytically determined elemental contents of PM of control and treated mice showed a correlation between ConA binding site number and cellular concentration of phosphorus or sulphur with the exception of a small group of PM which was characterized by a high content of sulphur and a low number of ConA binding site. This correlation was not found in normal mice.

Animals↗
PubMed1990

Effect of different fixatives on Con A surface receptors of mouse peritoneal macrophages.

The effects of glutaraldehyde, formaldehyde, or osmium tetroxide fixation on the number of labeled Con A surface receptors on mouse peritoneal macrophages were compared. Gold-labeled Con A receptors were found to be isolatedly arranged and evenly distributed on cell surfaces independent of the fixative used. Only cells preincubated with Con A and subsequently fixed by osmium tetroxide showed arrangement of labeled receptors in clusters. Significant differences were found in the number of Con A receptors per cell depending on the fixative used. The fluorescence intensity of FITC-Con A staining was detected spectrophotometrically, the characteristic X-rays of gold-labeled Con A receptors were determined by means of electron beam-induced X-ray microanalysis. The experimental results obtained both at light and electron microscopic level pointed to formaldehyde being the best fixative also for this purpose.

Animals↗
PubMed1990

[Cooperativity between surface receptors and cytoskeleton].

Numerous physiological reactions of cells in dependence on ligand receptor interactions, e.g. variation of growth and division, locomotion and intracellular movement, cell shape and others, depend directly or indirectly on the functional state of the cytoskeleton. Relations between ligand-mediated receptor movements (preferentially for interferon) at the cell surface, the internalization and intracellular transport are discussed in the context of structural and functional properties of the cytoskeleton (especially of the microtubule system). As basic aspects of the cooperation between cytoskeleton and receptors are regarded both the unstable structural-temporal interactions between receptor/ligand complexes and the cytoskeleton, the generation of force and movement, and the activation of the cytoskeleton to transport competence for receptor/ligand complexes.

Animals↗
PubMed1990

[SEM studies on IFN-receptor dynamics of cultured cells from mammals].

Visualization of rIFN-alpha 1 and -alpha 2 receptors on MDBK-cells was done by means of a two step method with gold-labelled monoclonal anti IFN-antibodies in the SEM. This binding showed a marked dependency from the temperature, concentration of the rHu-IFN, prefixation of the MDBK-cells, and time of incubation. This results are in agreement with findings of classical virological methods. By means of SEM was shown that the distribution and amount of the IFN-receptors on MDBK-cells depends strongly on the cell cycle and that not each was labelled. The results were discussed in connection with structural-functional alterations of the cytoskeleton.

Animals↗
PubMed1989

Determination of gold-labelled surface receptors on single cells by X-ray microanalysis.

A standardless X-ray microanalytical procedure has been developed to determine the number of gold-labelled surface receptors on whole single cells. The effect of the injection of K2PtCl4 into mice on gold-labelled concanavalin A (Con A) receptors on peritoneal macrophages was examined with an energy dispersive X-ray detector in an SEM. The numbers of gold particles seen in electron micrographs and estimated by fluorescence photometric measurements of fluorescein isothiocyanate-labelled Con A receptors were correlated with the X-ray microanalytical results.

Animals↗
PubMed1986

Effect of several fixatives on the density of concanavalin A binding sites of murine peritoneal macrophages determined by fluorescence microscopy and X-ray microanalysis.

The influence of various fixatives (glutaraldehyde, formaldehyde, OsO4) on the retention of antigenicity of peritoneal macrophages was studied by means of fluorescence microscopy, scanning electron microscopy, and X-ray microanalysis. After fixation with formaldehyde the Concanavalin A (Con A) binding sites were found to be highest, whereas the fixation with OsO4 results in loss of many binding sites. The fluorescence microscopic investigations of glutaraldehyde fixed cells is impaired by fixative induced fluorescence. Therefore X-ray microanalytical determinations show better results for these cells than fluorescence microscopic measurements. On contrary to direct labelling method the number of unspecific Con A binding sites on peritoneal macrophages labelled with the sandwich method is negligible.

Animals↗
PubMed1985

[Erythrocyte-associated plasma proteins, a further aspect of erythrocyte function?].

The amount of plasma proteins associated to erythrocytes was determined or calculated by using three different techniques. Thus, there are 3.48 X 10(12) g of protein in a single erythrocyte or 94.12 g of protein respectively in the total of all erythrocytes in a healthy man with a body weight of 70 kg. The mass of plasma protein associated to erythrocytes will decrease in case of immunocomplex aggregates or otherwise denatured plasma proteins being fixed to the erythrocyte surface so that from a purely calculating point of view protein amounts on a scale of up to 46% of all plasma proteins may enter the free blood plasma under extreme conditions. In this, an immediately efficient possibility of compensation is seen by the authors in case of an acute consumption of blood proteins.

Antigen-Antibody Complex↗
PubMed1982

[The altered membrane of the erythrocyte. I. Ultrahistochemical and biocellular investigations for the detection of activated acetylcholinesterase (ACHE) and demasking of IgG receptor sites (author's transl)].

Different states of the erythrocyte membrane with regard to its disintegration are characterized. The binding power of autologous and allogenic IgG, the degree of the activation of the membrane associated acetylcholinesterase (inhibited in the intact plasmalemma of red blood cells), and the membrane vesiculation served as criteria. The findings demonstrate that, obviously, the IgG binding increases in dependence on the extent of the disturbance of the membrane structure. The acetylcholinesterase is increasingly activated. The enzyme can be demonstrated by spectrophotometrical and ultrahistochemical methods. Microvesiculation is understood as expression of fundamental disturbances of the membrane structure. These disturbances express local remodelling processes in the membrane of banked red blood cells. Highly extended damage of red blood cells after mechanical stress, heat or urea incubation lead to comparatively high rates of vesiculation, partially even to cell fragmentation. Extremely spectrindeficient ghosts tend to microvesiculation, which leads to complete microvesicular decay of the ghost membrane. The membrane associated autologous IgG is demonstrated by means of immuneological and ultrahistochemical methods. Its importance as homeostatically effective immun-signal for the elimination of red blood cells aged in vivo or in vitro, ghosts and microvesicles by the reticulohistiocytic-system is evidenced by means of model experiments. Molecular mechanisms for unmasking of IgG-receptor sites and activation of acetylcholineesterase in the altered erythrocyte membrane are discussed.

Acetylcholinesterase↗