Strain LS3 Research Articles

Temperature-dependent dimorphism of the yeastArxula adeninivorans Ls3

Arxula adeninivorans Ls3 is described as an ascomycetous, arthroconidial, anamorphic, xerotolerant yeast, which was selected from wood hydrolysates in Siberia. By using minimal salt medium or yeast-extract-peptone-medium with glucose or maltose as carbon source it was shown that this yeast is able to grow at up to 48 degrees C. Increasing temperatures induce changes in morphology from the yeast phase to mycelia depending on an altered programme of gene expression. This dimorphism is an environmentally conditioned (reversible) event and the mycelia can be induced at a cultivation temperature of 45 degrees C. Depending on the morphology of strain Ls3 (yeast phase or mycelia) the secretion behaviour as well as the spectrum of polypeptides accumulated in the culture medium changed. The activities of the accumulated extracellular enzymes glucoamylase and invertase were 2 to 3 times higher in cultures grown at 45 degrees C than in those grown at 30 degrees C. While the level of the glucoamylase protein secreted from mycelia between 45 and 70 hours did not change, biochemical activity decreased after a cultivation time of 43 hours. It was shown that this effect depended on both the catabolic repression of the glucoamylase by glucose and the thermal inactivation of this enzyme in media without or with low concentrations of starch or maltose.

Comparative biochemical, genetical and immunological studies of glucoamylase producing Arxula adeninivorans yeast strains

Seven Arxula adeninivorans strains originating from The Netherlands (CSIR 1136, CSIR 1138 and CBS 8244T), South Africa (CSIR 1147, CSIR 1148 and CSIR 1149) and Siberia (Ls3) were compared concerning their secretory glucoamylase. Within the spectrum of secretory polypeptides obtained by SDS-polyacrylamide gel electrophoresis, the glucoamylase corresponding polypeptide, could be identified by means of specific antibodies directed against the glucoamylase of strain Ls3. The molecular masses of the glucoamylases vary from 84 to 95 kDa. After endoglycosidase F treatment of the secretory proteins, the N-linked carbohydrate content for each glucoamylase could be quantified at about 25%. Glucoamylase activity staining of secretory proteins separated under nondenaturing conditions revealed one glucoamylase active protein for the Dutch strains and two active forms for the strains originating from South Africa and Siberia. Highest activities of glucoamylase can be measured at the end of the exponential growth phase for each strain. The Dutch strain CSIR 1138 secretes the highest activity. Optimum values for temperature and pH were determined and compared. By means of pulsed field gel electrophoresis and Southern analysis, the glucoamylase corresponding gene could be localized on the second of the four chromosomes of each yeast strain.

Role of T lymphocytes in experimental Staphylococcus aureus arthritis.

Using a recently developed murine model of haematogenously induced Staphylococcus aureus, the authors have characterized the phenotypes and functional properties of inflammatory cells present in the synovium of arthritic mice. The results show that large numbers of granulocytes and macrophages were observed in the inflamed synovia within 24 h of inoculation of S. aureus strain LS-1. Many of the synovial macrophage-like cells strained for cytoplasmic IL-1 alpha and TNF-alpha. Subsequently (> or = 48 h later), a prominent infiltration of T lymphocytes, predominantly of CD4+ phenotype, was observed. Some of the T lymphocytes stained for IL-2 receptor and intracytoplasmic interferon-gamma (IFN-gamma). Surprisingly, in spite of the severe inflammatory process, very few cells expressed MHC class-II molecules in the arthritic synovia. In addition, in vivo depletion of CD4+ T-cells resulted in a considerably milder course of staphylococcal arthritis. The similarities in the phenotype expression of synovial cells and central role of T-cells in S. aureus arthritis as well as in non-infectious models of arthritis, indicate that the process governing joint destruction is likely to be the same, irrespective of the initial stimulus.

The Yeast Genus Trichosporon spec. LS3; Molecular characterization of genomic complexity

The genomic structure of an industrial yeast strain Trichosporon spec. LS3 was compared with Trichosporon adeninovorans type strain CBS 8244. The cot values, the portion of single copy sequences (CBS 8244: 10.9 x 10(9) D, LS3: 10.6 x 10(9) D) as well as of repetitive sequences (CBS 8244: 6.0 x 10(9) D, LS3: 5.5 x 10(9) D) per haploid genome and genome complexity of these strains (CBS 2844: 16.9 x 10(9) D, LS3: 16.1 x 10(9) D) have been analysed. Both strains show a high genome complexity. The mitochondrial DNA content was measured and compared. No plasmidal DNA was identified for both strains. A survey of the data of genomic DNA made it possible to postulate for each of both strains a haploid set of chromosomes. The intraspecific reassoziation values of the nuclear DNA from the strain LS3 and CBS 8244 are interpreted to confirm classification of these strains based on physiological and genetical properties into one species Trichosporon adeninovorans.

Comparative Study on Coat Proteins of an Attenuated, a Temperature Sensitive and Their Parent Strains of Tobacco Mosaic Virus

AbstractAn attenuated strain (L11A) of tobacco mosaic virus (TMV) induces no remarkable symptoms on tomato plants (Goto and Nemoto 1971) and has been used to protect tomato against virulent strains of TMV (Oshima 1981), A temperature sensitive strain (Ls1) of TMV was isolated and found to have a malfunction of virus movement from cell to cell (NISHI‐GUCHI et al. 1978, 1980). Those two strains are derived from a wild virulent strain (L). Coat proteins of them were compared with one another and with that of Dahlemense (D) strain of TMV, in order to see whether coat protein was associated with their respective characters.The coat proteins of the four strains behaved similar in both SDS‐polyacrylamide gel and 8 M urea polyacrylamide gel electrophoresis, suggesting that they are similar in molecular weight and charging effect in the gels. There was no significant difference in chromatographic pattern of tryptic peptides among the four strains. Amino acid compositions of tryptic peptides revealed that three strains, L11A, Ls1 and L, were identical to one another and that they differed from D slightly. These results suggest that coat protein is related neither to virus attenuation of L11A nor to the malfunction of Ls1.

Effects of furazlocillin, a beta-lactam antibiotic which binds selectively to penicillin-binding protein 3, on Escherichia coli mutants deficient in other penicillin-binding proteins

Furazlocillin binds selectively to penicillin-binding protein 3 (PBP-3), prevents septation of Escherichia coli, and allows the cells to form long filaments without lysis. The effect of furazlocillin on the morphology, autolysis, and murein synthesis of E. coli mutants deficient in either PBP-1A, PBP-1Bs, or PBP-2 was studied. The results reveal that PBP-1A and PBP-1Bs functions are not equivalent since furazlocillin affects the morphology, autolysis, and murein synthesis of PBP1A- mutants quite differently from that of PBP-1Bs mutants. Different "PBP-2-" mutants were found to respond to furazlocillin in dramatically different ways: strain LS-1 cells formed elongated rods with a central bulge which eventually lysed, whereas SP6 cells formed stable "barbells" in which the two daughter cells were well separated but remained connected by a thick central region.