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  • 101
    ISSN: 0749-503X
    Schlagwort(e): DNA-binding proteins ; ARS ; centromere ; yeast ; Saccharomyces cerevisiae ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: GFI and GFII are abundant DNA-binding proteins in the yeast Saccharomyces cerevisiae. Binding sites for GFI conform to the sequence 5′-RTCRYNNNNNACG-3′. This consensus can also accommodate the recognition sequence for the ARS1-binding factor ABFI. Results of retardation-competition assays, limited proteolysis experiments, molecular weight determinations based on denaturation-renaturation procedures and mobility shift assays of protein-DNA complexes formed in the presence of a monoclonal antibody raised against ABFI suggest strongly that GFI and ABFI are the same protein. Similarly, GFII appears to be identical to the centromere-binding protein CPFI (alias CP1), since both proteins bind to the CDEI motif of yeast centromeres (5′-RTCACRTG-3′) and cannot be detected in a cpf1 disruption mutant yeast strain. In addition, based on denaturation-renaturation studies, both factors appear to have molecular weights in the same range of 53-62 kDa.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 102
    ISSN: 0749-503X
    Schlagwort(e): Hansenula polymorpha ; expression system ; S and L surface antigens ; hepatitis B vaccine ; multimeric ; non-homologous integration ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: An expression system has been developed for the methylotrophic yeast Hansenula polymorpha and used to co-express both the L (preS1-S2-S) and S hepatitis B surface antigens (HBsAg) under the control of strong methanol-inducible promoters derived from the methanol oxidase and from the formate dehydrogenase genes. A unique feature of this H. polymorpha expression system is the possibility of integrating up to 100 copies of an expression cassette via a multimeric integration mechanism. Several multimeric integrants containing various numbers of L and S expression cassettes were constructed to give a spectrum of strains characterized by different L to S ratios. The expression level of S antigen was 5-8% of the total soluble cell protein. Analysis by sucrose and CsCl density gradient centrifugation and by particle-specific immunoassays demonstrated that the synthesized HBsAg spontaneously assembled into composite subviral particles containing both S and L proteins. Only a minor portion of the L protein was found to be glycosylated. These H. polymorpha-derived composite particles can be used for the production of a hepatitis B virus vaccine with the potential for improved immunogenicity due to the presence of a wider spectrum of epitopes and negligible glycosylation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 103
    ISSN: 0749-503X
    Schlagwort(e): Plasmids ; gene disruption ; selectable cassettes ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The YDp plasmids (Yeast Disruption plasmids) are pUC9 vectors bearing a set of yeast gene disruption cassettes, all uniform in structure and differing only in the selectable marker used (HIS3, LEU2, LYS2, TRP1 or URA3). The markers, surrounded by translational termination codons, are embedded in the slightly modified sequence of the pUC9 multiple cloning sites.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 104
    ISSN: 0749-503X
    Schlagwort(e): Asporogenic yeast ; Candida tropicalis ; Peroxisomes ; POX genes ; pulsed-field gel electrophoresis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The peroxisomes of the asporogenic yeast Candida tropicalis contain about 20 major polypeptides (PXPs). We have isolated a number of genes encoding them; 11 POX genes encoded independent PXPs and three POY genes were likely to encode three other PXPs. To locate these genes on the chromosomes, chromosomes of C. tropicalis were separated by pulsed-field gel electrophoresis. Eight chromosomal bands were observed over the range of 1·0 Mbp (band I) to 2·8 Mbp (band VIII); the genome size was estimated to be about 20 Mbp. Southern blot analysis showed that ten genes were on band V, three genes were on band IV, and the other gene was on band VI. Three genes gave hybridization signals of nearly equal intensity on two different chromosomal bands: POX6A and POX8B, on bands V and VII; and POX8A, on bands IV and VI. Ribosomal RNA genes also hybridized to two bands, VI and VII. Most genes assigned to only one band hybridized to two restriction fragments produced by either NotI or SfiI endonuclease. The results suggested that C. tropicalis was diploid and that restriction sites were conserved little between homologues. The three POX genes that were found on two chromosomal bands hybridized to not more than two restriction fragments, implying that the allelic genes were present on different chromosomal bands.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 105
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 539-546 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; heat-shock element ; lacZ induction ; growth state ; ubi4, ubc4, ubc5, pep4-3 mutants ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Heat-shock induction of heat-shock protein genes is due to a specific promoter element (the heat-shock element, HSE). This study used lacZ under HSE control (HSE-lacZ) to characterize HSE activity in Saccharomyces cerevisiae cells of different physiological states and differing genetic backgrounds.In batch fermentations HSE-lacZ induction by heat shock was maximal in exponential growth, and showed marked decline with the approach to stationary phase. Expression in the absence of heat shock was unaffected by growth phase, indicating that the growth-dependent expression of many yeast heat-shock genes uses promoter elements in addition to the HSE. Heat-induced expression was strongly influenced by the temperature at which cultures were grown. While basal, uninduced expression was constant during growth at different temperatures to 30°C, induction by transfer to 39°C was reduced by increases in growth temperature as low as 18-24°C. Maximal HSE-lacZ induction (30- to 50-fold) was in cultures grown at low temperatures (18-24°C), then heat shocked at 39°C. Ethanol was a poor inducer. Mutations having little effect on HSE-lacZ expression included a respiratory petite; ubi4 (which inactivates the polyubiquitin gene); also ubc4 and ubc5 (which each inactivate one of the ubiquitin ligases involved in degradation of aberrant protein). pep4-3 increased both basal and induced β-galactosidase about two-fold, probably because of slower turnover of this enzyme in pep4-3 strains.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 599-606 
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; Zygosaccharomyces rouxii ; plasma membrane ; proton-ATPase ; salt-tolerance ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Plasma membrane was isolated from the salt-tolerant yeast Zygosaccharomyces rouxii and from Saccharomyces cerevisiae. The ATPase in the plasma membrane of Z. rouxii cells was a typical proton-ATPase as judged by testing with various ATPase inhibitors. There were slight differences in the pH optima of activities and in the sensitivity to sodium chloride (NaCl) and potassium chloride (KCl) of the ATPase from Z. rouxii and S. cerevisiae. The specific ATPase activity from Z. rouxii was higher in cells grown in a medium containing 2 M-NaCl than in those not containing NaCl. No in vivo activation by incubation with glucose was observed in Z. rouxii cells and the specific ATPase activity was independent of the growth phase, unlike S. cerevisiae cells.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 107
    ISSN: 0749-503X
    Schlagwort(e): Cell cycle ; toxin ; K. lactis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The Kluyveromyces lactis toxin is a heterotrimeric protein which irreversible arrests proliferation of sensitive Saccharomyces cerevisiae cells in the G1 phase of the cell cycle. By expressing the γ subunit of the toxin in sensitive yeast cells from a conditional promoter, it was previously demonstrated that it alone is required for inhibition (Tokunaga et al. (1989). Nucleic Acids Res. 17, 3435-3446). Here we show that, like native exogenous toxin, intracellular γ subunit expression promoters a striking arrest of sensitive cells in G1. However, unlike the G1 arrest caused by native toxin, that induced by the γ subunit alone does not result in reduced cellular viability and is fully and rapidly reversible, suggesting that the G1 arrest and the irreversibility of action may reflect different aspects of the toxin's interaction with sensitive cells. We have selected a large number of S. cerevisiae mutants which are highly resistant to the toxin in order to study its mode of action in more detail. Complementation analysis demonstrated that all but one of the mutants were recessive and these defined four separate genes. Members of two complementation groups concurrently acquired resistance to intracellular γ subunit expression, suggesting that they contain a modified toxin target site. The other two genes appear to be required for entry of the γ subunit into the sensitive cell since these mutants, while refractory to exogenous toxin, were fully sensitive to intracellular γ subunit expression.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 108
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 657-678 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 109
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 699-716 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; heat shock ; protein phosphorylation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Hsp70 proteins have been highly conserved throughout evolution. As a first step in a structure-function analysis of hsp70, we constructed and analysed the consequences of mutations in a portion of the SSA1 gene, a member of the Saccharomyces cerevisiae HSP70 multigene family, that encodes a nearly invariant region near the amino terminus. Analysis of strains expressing SSA1 proteins with alterations at positions 8, 11 and 15 showed that these conserved residues within this region are critical for normal functioning of the protein. SSA1 protein containing either of two changes at position 15 was able to slightly complement the inviability of an ssa1ssa2ssa4 strain, but was inactive in other complementation assays. The other mutant proteins tested were unable to complement any tested phenotype. Effective interallelic complementation of several phenotypes was observed when a mutant protein substituted at position 8 was expressed in the same cell with either of two proteins carrying substitutions at position 15, suggesting that hsp70 acts as a multimer. Evidence from previous studies suggests that hsp70 proteins engage in ATP-driven cycles of binding and release from peptides. The ability of the mutant proteins to bind ATP and a peptide was tested. The Ssa 1p carrying a substitution at position 8, which inhibits growth of cells carrying wild-type SSA proteins, showed a defect in release from a peptide relative to wild type. Two mutations, one each at position 8 and 15, resulted in accumulation of phosphorylated isoforms which may be a normal, transient hsp70 intermediate.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 110
    ISSN: 0749-503X
    Schlagwort(e): Chromosome III ; strain polymorphisms ; DNA replication ; mRNA stability ; ribosomal proteins ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We report the sequence of a 7·5 kb region lying between the CRY1 and MAT loci of chromosome III from Saccharomyces cerevisiae. This region lies in the overlap between two major contigs used for the generation of the complete nucleotide sequence of this chromosome. Comparison of this sequence with those reported previously for this overlap [Thierry et al. (1990) Yeast 6, 521; Jia et al. (1991) Yeast 7, 413] reveals 38 nucleotide differences, 45% of which generate changes in the amino acid sequences of the four genes in this region (YCR591, YCR592, YCR521 and YCR522). These differences appear to reflect true sequence polymorphisms between the two yeast strains used to generate the clones used in the sequencing project. Three of the four genes in this region display weak homologies to proteins in the PIR database. Some properties of YCR521 are analogous to those of ribosomal protein genes. However, the functions of all four genes remain obscure.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 813-821 
    ISSN: 0749-503X
    Schlagwort(e): Hansenula polymorpha ; alcohol oxidase ; peroxisome-deficient mutant ; selective inactivation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have studied selective inactivation of alcohol oxidase (AO) in two peroxisome-deficient (PER) mutants of the yeast Hansenula polymorpha. In these mutants high activities of cytosolic AO are induced by different growth conditions. At enhanced expression rates AO is arranged in large crystalloids in the cytosol, whereas smaller crystalloids are often observed inside the nucleus. Transfer of cells of the PER mutant 125-2E, which completely lacks peroxisomes, to glucose-excess conditions did not lead to degradative inactivation of AO and catalase as observed in wild-type (WT) cells used as a control. The gradual decrease in enzyme activities in the PER mutant could be accounted for by dilution of existing enzyme into newly formed cells as a result of growth. Morphologically, degradation of the cytosolic crystalloids was also not observed. Similar results were obtained with a second PER mutant (strain 124-2D), impaired in the import of peroxisomal matrix proteins. This mutant is characterized by the presence of small peroxisomes and large cytosolic AO crystalloids. Upon a shift of cells to glucose-excess conditions only part of the small peroxisomes present in these cells were degraded by mechanisms similar to those observed in WT cells placed under identical conditions. These results indicate that degradative inactivation of AO in H. polymorpha is strictly dependent on the localization of the enzyme inside peroxisomes and furthermore suggests that the mechanisms triggering this process are not directed against AO protein, but instead, to the membrane surrounding the organelle. Transfer of cells to methanolor ethanol-containing media both resulted in modification inactivation of AO. Under these conditions also the AO crystalloids remained unaffected by incubation in the new environment.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 112
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 857-858 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; genetic analysis ; respiratory deficiency ; protease genes ; drug resistance genes ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 113
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 890-890 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 114
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 889-889 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 115
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991) 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 933-941 
    ISSN: 0749-503X
    Schlagwort(e): BAP1 ; branched-chain amino acids ; transport ; permease ; uptake ; L-isoleucine ; L-leucine ; L-valine ; sulfometuron methyl ; yeast ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: In order to isolate mutants with impaired uptake of branched-chain amino acids, mutants were induced which on complex medium were sensitive to an inhibitor of branched-chain amino acid biosynthesis. Eighteen mutants of independent origin were found. Ten of them were assayed for branched-chain amino acid uptake. Three of these were impaired in the uptake of L-valine, L-isoleucine and L-leucine, while the rest were unaffected in uptake of any of the three amino acids. Kinetics of the uptake by one selected mutant and the parental strain S288C were compared to models for one or two systems obeying Michaelis-Menten kinetics. This analysis suggested that a high-affinity system for all three amino acids is absent in the mutant, whereas low-affinity uptake of L-isoleucine and L-leucine by one or more systems remains unaffected. Moreover, medium-affinity uptake components for L-valine and L-leucine, not originally seen in the wild type, were identified in the mutant. In the wild type, 10 mM of any of the amino acids L-alanine, L-cysteine, L-isoleucine, L-leucine, L-tryptophan and L-valine reduce uptake of any of the three branched-chain amino acids. We propose that a permease responsible for high-affinity uptake of the branched-chain amino acids in strain S288C is partially or completely inactive in the mutant. Tetrad analysis shows that the phenotype can be ascribed to a single Mendelian gene. The wild-type allele is denoted BAP1 for branched-chain amino acid permease. The BAP1-dependent system is different from the general amino acid permease.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 117
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 971-979 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The nucleotide sequence of a 1558 bp DNA fragment from the right arm of chromosome III of Saccharomyces cerevisiae contains an open reading frame of 954 nucleotides with coding potential for a protein with high similarity to the ubiquitous cyclophilins which are both peptidyl-prolyl cis-trans isomerases and cyclosporin A-binding proteins. It should, therefore, represent the third gene (SCC3) of this kind from S. cerevisiae. SCC3 is present in a single copy in the genome of S. cerevisiae and results in a constitutively expressed 1·2 kb transcript during cell growth. Its putative protein product (Scc3) contains two hydrophobic cores, one at the amino terminal, 20 amino acids long, which could serve as a signal peptide, and the other one at the carboxyl end with a structure similar to a transmembrane helix. These findings suggest that Scc3 could be a secretory or, more likely, a transmembrane protein. The only cyclophilin with similar structure to that of Scc3 is ninaA from Drosophila melanogaster, a transmembrane protein which seems to be implicated in the correct folding and/or intercalation of rhodopsin in the endoplasmic reticulum of the fly photoreceptors (Stamnes, M. A. et al., Cell 65, 219-227, 1991). In addition, the amino and the carboxy regions of Scc3 and ninaA share a significant level of homology, which suggests that they have a similar function, albeit for different target proteins.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 118
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 226-237 
    ISSN: 0192-253X
    Schlagwort(e): Nuclear determination ; macronucleus ; ciliates ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Gene mutations that interfere with macronuclear development in Paramecium were obtained by selecting lines that failed to produce normal macronuclear anlagen following the second autogamy after mutagenesis. The mutants fell into several complementation groups. There was one case of apparent intragenic noncomplementation among the eight mutants examined. In the stronger mutants, macronuclear anlagen were not formed, and all four mitotic products of the posfzygotic divisions of the synkaryon remained as micronuclei. Under semirestrictive conditions, cells often contained a single anlage, suggesting that determination of anlagen was a discrete event for each nucleus. The missing anlagen trait was recessive and associated with a strong maternal effect. The phenocritical period of one of the stronger alleles, aala, began at the second postzygotic division and ended with the first morphological differentiation of macronuclear anlagen. Nuclear migration in this mutant was abnormal. Under restrictive conditions, the posterior products of the second postzygotic division reached a posterior-most position, which was 8% of cell length more anterior than that of the most posterior nuclei in wild-type cells. Under permissive conditions, the pattern of migration was intermediate between that of wild-type cells and mutants under fully restrictive conditions. The patterns of nuclear migration were consistent with the nuclear growth kinetics.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
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  • 119
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991) 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 120
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 238-252 
    ISSN: 0192-253X
    Schlagwort(e): Enhancer detection ; embryogenesis ; cell lineage ; P-element ; β-galactosidase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: To generate cell- and tissue-specific expression patterns of the reporter gene lacZ in Drosophila, we have generated and characterized 1,426 independent insertion strains using four different P-element constructs. These four transposons carry a lacZ gene driven either by the weak promoter of the P-element transposase gene or by partial promoters from the even-skipped, fushi-tarazu, or engrailed genes. The tissue-specific patterns of β-galactosidase expression that we are able to generate depend on the promoter utilized. We describe in detail 13 strains that can be used to follow specific cell lineages and demonstrate their utility in analyzing the phenotypes of developmental mutants. Insertion strains generated with P-elements that carry various sequences upstream of the lacZ gene exhibit an increased variety of expression patterns that can be used to study Drosophila development.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 121
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 281-292 
    ISSN: 0192-253X
    Schlagwort(e): Actin function ; cell wall ; cytoskeleton ; fusion proteins ; mating ; 10 nm filaments ; yeast ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The Saccharomyces cerevisiae CDC3, CDC10, CDC11, and CDC12 genes encode a family of homologous proteins that are not closely related to other known proteins [Haarer BK, Ketcham SR, Ford SK, Ashcroft DJ, and Pringle JR (submitted)]. Temperature-sensitive mutants defective in any of these four genes display essentially identical pleiotropic phenotypes that include abnormal cell-wall deposition and bud growth, an inability to complete cytokinesis, and a failure to form the ring of 10 nm filaments that normally lies directly subjacent to the plasma membrane in the neck region of budding cells. We showed previously that the CDC3 and CDC12 gene products localize to the region of the mother-bud neck and are probably constituents of the ring of 10 nm filaments. We now report the generation of polyclonal antibodies specific for the CDC11 product (Cdc11p) and the use of these antibodies in immunofluorescence experiments with wild-type and mutant cells. The results suggest that Cdc11p is also a constituent of the filament ring, and thus support the hypothesis that the S. cerevisiae 10 nm filaments represent a novel type of eukaryotic cytoskeletal element. Cdc11p and actin both localize to the budding site well in advance of bud emergence and at approximately the same time, and both proteins also remain localized at the old budding site for some time after cytokinesis. Cdc11p also localizes to regions of cell-wall reorganization in mating cells and in cells responding to purified mating pheromone. Surprisingly, most preparations of affinity purified Cdc11p-specific antibodies also stained the nuclear and cytoplasmic microtubules. Although this staining probably reflects the existence of an epitope shared by Cdc11p and some microtubule-associated protein, the possibility that a fraction of the Cdc11 p is associated with the microtubules could not be eliminated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 122
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991) 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 123
    ISSN: 0192-253X
    Schlagwort(e): t/complex ; gene expression ; testis ; in situ hybridization ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The t-complex of the mouse occupies the proximal half of chromosome 17 and cantains genes which have profound effects on spermatogenesis. Mutations of several loci in the t-complex appear to interact to cause male sterility or transmission ratio distortion (TRD).By cDNA screening or chromosomal walking we have identified seven genes, which are expressed in the germ cells of testis and map to various regions of the t-complex. These genes were named t-complex testis-expressed (Tctex) genes. An analysis of their expression patterns in testes from +/+, +/t, and t/t mice was done by in situ hybridization and by northern blotting. Six genes begin to be expressed at the pachytene stage: Three of them are more abundant at pachytene stage, while three others are more abundant at postmeiotic stages. One gene is expressed at all the stages of spermatogenesis. Interestingly, four Tctex genes show differences in the amount of transcript between wild-type and t-mutant testes. The chromosomal location and expression pattern imply that Tctex genes might be candidate genes for sterility or TRD.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 124
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 333-341 
    ISSN: 0192-253X
    Schlagwort(e): Maternal effect gene ; DNA sequencing ; protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We report the sequence of the Drosophila maternal effect gene swallow, one of the genes whose product is required for the localization of bicoid message during Drosophila oo-genesis. The inferred swallow protein contains a domain that is predicted to be an amphipathic α-helix similar to those implicated in protein:protein associations in other systems. Another part of the predicted protein appears to be a diverged RNA-binding motif. We discuss these structural features in light of the function of the swallow protein in the bicoid message localization process.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 125
    ISSN: 0192-253X
    Schlagwort(e): Chloroplast biogenesis ; temperature-shift analysis ; gene expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The ability to form functionally active chloroplasts is determined at a certain early stage of leaf development in three non-allelic temperature-sensitive virescent mutants of rice. Temperature-shift analysis, together with anatomical observations, indicates that the intrinsic developmental signals of the virescent genes are expressed at the stage immediately following the formation of basic leaf structure, but just before the onset of leaf elongation. These signals control the expression of chloroplast-encoded genes but do not affect the subsequent morphological development of the leaf or the photo-regulation of the expression of nuclear genes encoding chloroplast proteins.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 126
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 382-392 
    ISSN: 0192-253X
    Schlagwort(e): Plant development ; embryogenesis ; morphogenesis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Genetic analysis of plant em-bryogenesis has been approached in part through the isolation and characterization of recessive embryonic mutants. The most extensive studies have dealt with maize and Arabidopsis. The high frequency of mutants defective in plant embryogenesis is consistent with the presence of many target genes with essential functions at this stage of the life cycle. Some mutants are likely to be defective in genes with general housekeeping functions. Others should facilitate the identification of genes with a more direct role in the regulation of morphogesis. Over 300 embryonic mutants of Arabidopsis isolated following chemical mutagenesis and T-DNA insertional mutagenesis are currently being analyzed. This collection includes embryonic le-thals, defectives, and pattern mutants. Developmental abnormalities include the presence of fused cotyledons, twin embryos, abnormally large suspensors, distorted epidermal layers, single cotyledons, enlarged shoot apices, pattern deletions and duplications, embryos with altered patterns of symmetry, bloated embryos with giant vacuolated cells, reduced hypocotyls that fail to produce roots, and embryos that protrude through the seed coat late in maturation. This review describes the isolation and characterization of embryonic mutants of Arabidopsis and their potential application to plant biology. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 127
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 393-402 
    ISSN: 0192-253X
    Schlagwort(e): Clonal variation ; gene expression ; DNAase I hypersensitive sites ; matrix-associated regions ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The chinchilla-mottled (cm) mutation at the mouse tyrosinase-encoding locus leads to a transversely striped pattern of dark- and light-grey coat colors in homozygotes. The same basic pattern occurs in various other genotypes and has previously been found to represent the clonal developmental history of melanocytes. In a homozygote such as cm/cm, cis-acting mechanisms would be expected to account for the color differences. To search for these mechanisms, the genomic structure of the mutation was examined and compared with the wild-type, and its function was compared in cultured melanocyte clones of the respective colors. Evidence from restriction mapping indicated that the coding region of the mutant gene resembles that of the fully and uniformly pigmented wild-type. However, the upstream sequences are rearranged in the mutation. The rearrangement begins 5 kb 5′ of the transcription initiation site and is estimated to encompass at least 30 kb of distal upstream sequence. At least two stable functional states of the cm gene were detectable: Light-cell clones have low levels of tyrosinase-specific transcription, reduced DNAase I sensitivity of tyrosinase chromatin, and no detectable hypersensitive sites near the gene; dark-cell clones have higher (but subnormal) levels of transcription, greater sensitivity of chromatin to DNAase I, and a hypersensitive site in the promoter region. The changed relation between the structural gene and its upstream region may separate it from cis-acting control elements, resulting in reduced and variable ability to achieve the appropriate chromatin configuration near the time of melanocyte determination; differences in expression among clonal initiator cells are then mitotically perpetuated. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 128
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 78-81 
    ISSN: 0192-253X
    Schlagwort(e): Dictyostelium ; growth factor ; filipin mutant ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Polypeptide hormones, recognized for their ability to regulate cell growth and differentiation, have been classified as growth factors. These growth factors have been extensively described in higher eukaryotic organisms and cell lines [Hedin and Westermark, Cell 37:9-20, 1984]. Here we report the identification and partial characterization of a putative growth factor present in vegetative amoebae of the cellular slime mold Dictyostelium discoideum. A mutant was selected and found to be temperature sensitive due to the absence of an extracellular protein suggestive of a growth factor. The putative growth factor (DGF) is a protein resistant to both heat and strong detergent treatment but sensitive to reducing agents. The physiological significance of DGF is as yet unknown. DGF is of interest both in relation to understanding the events which control cell proliferation in Dictyostelium and in its relationship to other known growth factors.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 129
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 82-87 
    ISSN: 0192-253X
    Schlagwort(e): PSF ; discoidin I ; growth ; development ; gene regulation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: During growth, Dictyostelium cells continuously secrete a factor, PSF, that accumulates in proportion to cell density. At sufficient concentration, it triggers the production of discoidin I and certain lysosomal enzymes. Our earlier studies demonstrated these effects of PSF on protein and enzyme levels [Clarke et al., Differentiation 34:79-87, 1987; Clarke et al., Dev Genet 9:315-326, 1988]. In the present study, we have examined whether PSF induces increased mRNA levels. By Northern blot analysis, we have found that discoidin I mRNA accumulates in exponentially growing NC4 cells as the cells reach high density; significant levels of mRNA are detectable in cells growing either on plates or in suspension, beginning about four generations before the end of exponential growth. High levels of discoidin I mRNA are also found in low-density cells grown in the presence of buffer conditioned by high-density cells. These results indicate that PSF induces the accumulation of discoidin I mRNA. Other “early developmental” genes, pCZ22 and the early I genes (16, 18, and 111), are also expressed in exponentially growing cells at high density or in the presence of conditioned buffer. We conclude that several genes previously found to be preferentially expressed very early in development are actually induced during late exponential growth by PSF.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 130
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 163-169 
    ISSN: 0192-253X
    Schlagwort(e): Prespore gene ; gene disruption ; EGF-like repeats ; gene structure ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We present the nucleotide sequence of the cell type specific prespore gene EB4 which encodes a protein containing a hydrophobic leader sequence and two distinct domains of amino acid repeats. By RNase protection experiments we have determined the genomic organization of the gene which differs substantially from the previously published data. An antibody directed against one of the repeat structures (hexamer repeat) specifically reacts with a developmentally regulated antigen of 58 kd. Gene disruption transformants were obtained by transformation with a genomic DNA fragment. The transformants express a 3′ truncated mRNA and do not react with the anti-hexamer antibody. So far, we could not detect any phenotypic aberrations in the transformed cell line.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 131
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 154-162 
    ISSN: 0192-253X
    Schlagwort(e): Cysteine proteinase ; Dictyostelium discoideum ; Dictyostelium mucoroides ; Polysphondylium pallidum ; spore ; macrocyst ; microcyst ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Cysteine proteinase activities have been determined using gelatin-SDS-PAGE analysis and assays based on peptide nitroanilides. Vegetative myxamoebae of all species examined contain high levels of cysteine proteinose activity present in multiple forms. In both Dictyostelium discoideum and Polysphondylium pallidum the proteinase content is dependent on whether the cells are grown axenically or in association with bacteria. In all instances development is accompanied by a decreased intracellular cysteine proteinase activity. This occurs during the formation of fruiting bodies in D. discoideum, microcysts in P. pallidum, and macrocysts in Dictyostelium mucoroides. Significant quantities of proteinase activity are always secreted by myxamoebae immediately on starvation. In D. mucoroides this leads to an almost total depletion of intracellular cysteine proteinases by the aggregation stage. As a consequence of this depletion it has been relatively easy to detect a developmentally regulated accumulation of cysteine proteinases at the enzyme activity level, something which has not yet proved possible with D. discoideum. Three cysteine proteinases are produced as D. mucoroides macrocysts develop and mature. In the case of microcyst formation in P. pallidum the proteinase contents of the developing cells and of the microcysts are dependent on how the myxamoebae are grown. In this developmental pathway at least, there is no absolute requirement for specific proteinases to be present (or absent) at a particular stage. The diversity of cysteine proteinases found in cellular slime molds and the variety of features apparent in their regulation suggest that they will prove to be very useful for investigating features of the structure/function relationships in this important group of enzymes.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 132
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 255-260 
    ISSN: 0192-253X
    Schlagwort(e): Chitin-binding ; plant defense ; gramineae lectins ; tissue-specific expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 133
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 261-271 
    ISSN: 0192-253X
    Schlagwort(e): Transposable elements ; gene tagging ; regulatory genes ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The ability of transposable elements to generate gene mutations by excising from one site in the genome and reintegrating into new, different sites elsewhere in the genome has led to the development of procedures whereby the elements can be used to tag specific gene sequences for eventual isolation and analysis through gene cloning. This transposon tagging strategy is particularly useful in those situations where limited knowledge of the biochemistry of the target gene precludes gene cloning by conventional strategies. This approach, in conjunction with the more general insertional mutagenesis approach using T-DNA, has led to the cloning and subsequent analysis of several genes from higher plants involved in particular developmental processes. Studies of this nature should eventually shed light on the precise molecular mechanisms utilized to regulate and control cellular differentiation in plants.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 134
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 272-280 
    ISSN: 0192-253X
    Schlagwort(e): Cell differentiation ; cyclic AMP ; spore viability ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Sporogenous mutants of the cellular slime mold Dictyostelium discoideum are defined as mutants which are able to undergo terminal differentiation into spores in monolayer cultures in the presence of millimolar amounts of exogenous cyclic AMP. We describe the morphological development and cellular differentiation of a collection of 12 independently isolated sporogenous mutants of strain V12 M2. All mutants develop more rapidly than do wild-type at an air-water interface, display aberrant morphogenesis, and show overt spore and stalk differentiation as soon as 4 hr after starvation. All mutants differentiate in submerged monolayer culture in the presence of cAMP into variable proportions of spores and stalk cells. A number of the mutants also form both stalk cells and spores in submerged culture in the absence of exogenous cAMP. The spores formed by many of the mutants have a greatly reduced viability. Using parasexual genetics, we have found that two of the 12 mutants analyzed are dominant to wild-type and the remaining ten fall into a minimum of four complementation groups, the overall analysis thus yielding a minimum of four and a maximum of seven complementation groups. Intracellular cAMP levels in vegetative cells are significantly elevated in the two dominant mutants but are similar to wild type in all the other mutants.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 135
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 293-298 
    ISSN: 0192-253X
    Schlagwort(e): Neural development ; messenger RNA ; somatostatin ; glial fibrillary acid protein ; proteolipid protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: To examine the effects of ethanol exposure on neural development, pregnant rats were fed a liquid diet in which 37.5% of the total caloric content was ethanol-derived. The developmental appearance of the messenger RNAs coding for preprosomatostatin, glial fibrillary acidic protein, and proteolipid protein was examined by Northern blotting of total cellular RNA obtained from forebrain and hindbrain at various times after birth. In general, there was a delay in the developmental pattern of appearance of these mRNAs which was most noticeable at the early postnatal times. These results suggest that the previously reported delay in neural maturation is reflected at the level of the gene expression.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 136
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 415-422 
    ISSN: 0192-253X
    Schlagwort(e): Trisomic mice ; fetal liver cell transplantation ; radiation chimeras ; trisomic hematopoiesis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The life span of murine trisomies is limited to the fetal or early postnatal period. However, rescue of the hematopoietic system of fetal mice with trisomies (Ts) 12, 13, 14, 16, 18, and 19 is possible by transplanting hematopoietic stem cells from the liver into lethally irradiated adult hosts. Thus, radiation chimeras with permanent and almost complete trisomic hematopoietic and lymphocytopoietic systems were constructed. The longest documented survival of a trisomic graft was 12 months in Ts 19 chimeras. Blood counts in trisomic chimeras reveal a marked anemia in Ts 16 chimeras; lymphocytopenia in Ts 12, Ts 16, and Ts 19 chimeras; and granulocytopenia in Ts 18 chimeras. Survival rates of Ts 12, Ts 18, and Ts 19 chimeras were not different from those of the respective controls, whereas survival rates of chimeras with Ts 13 and Ts 16 hematopoiesis were markedly reduced and that of Ts 14 chimeras only slightly reduced. These results indicate that transplanted hematopoietic stem cells from Ts 13, Ts 14, and Ts 16 fetuses exhibit relevant genetically determined defects, resulting in a reduced restoration capacity of hematopoietic organs and/or deficiencies of differentiated blood cells. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 137
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 403-414 
    ISSN: 0192-253X
    Schlagwort(e): Mouse ; Mus musculus ; Mus caroli ; interspecific hybrids ; embryo ; gene expression ; glucose phosphate isomerase ; artificial insemination ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Hybrid Mus musculus × Mus caroli embryos were produced by inseminating M. musculus (C57BL/Ola Ws) females with M. caroli sperm. Control M. caroli embryos developed more rapidly than did control M. musculus embryos and implanted approximately 1 day earlier. At 1 1/2 days, both the hybrid embryos and those of the maternal species (M. musculus) had cleaved to the 2-cell stage. By 2 1/2 days some of the hybrids were retarded compared to M. musculus, and by 3½ days most were lagging behind. This is consistent with the idea that the rate of development of hybrid embryos declines once it becomes dependent on embryo-coded gene products.We have used this difference in rate of preim-plantation development, between hybrid and M. musculus embryos, to try to determine whether the activation of embryonic Gpi-1s genes, that encode glucose phosphate isomerase (GPI-1), is age-related or stage-related. In control M. musculus embryos (both mated and Al groups), the GPI-1AB and GPI-1A allozyme, indicative of paternal gene expression, were detected in 7 of 9 samples of 3 1/2-day compacted morula stage embryos and were seen in all 19 samples of 31/2-day blastocysts. In hybrid embryos, these allozymes were detected 1 day later. They were not detected in any 31/2-day samples (12 samples of compacted morulae) but were consistently detected at 4½ days (4 samples of blastocysts and 2 samples of uncompacted morulae). Our interpretation of the results is that gene activation in hybrid embryos is stage-specific, rather than age-specific, and probably begins around the 8-cell stage, with detectable levels of enzyme accumulating later. Analysis of GPI-1 elec-trophoresis indicated that both the paternal (M. caroli) and maternal (M. musculus) Gpi-1s alleles were equally expressed in hybrid embryos and that the paternally derived allele was not activated before the maternally derived allele. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 138
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991) 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 139
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 423-430 
    ISSN: 0192-253X
    Schlagwort(e): Zea mays ; superoxide dismutase ; differential gene expression ; stem lignification ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The temporal and spatial patterns of expression of the Cat and Sod genes encoding the multiple catalases and superoxide dismutases in maize have been examined throughout stem development. Three stages of stem development have been defined based upon catalase activity profiles and stem internode elongation. At stage 1, catalase activity is low and internodes remain short; at stage 2, catalase activity dramatically increases and internodes rapidly elongate; and at stage 3, catalase activity decreases to levels intermediate to stage 1 and 2, and internode elongation ceases. Zymogram analysis and immunoassays show that only the CAT-3 catalase isozyme is present in the stem, even though both Cat1 and Cat3 mRNAs accumulate throughout stem development. Cat2 mRNA is not detectable in the developing stem. In full-grown stems catalase is localized primarily in the sclerenchyma beneath the epidermis and around the vascular bundles and may possibly play a role in lignification. Unlike catalase, all the superoxide dismutase (SOD) isozymes and transcripts are present in the developing stem. Thus, these two major antioxidant gene-enzyme systems show differential patterns of expression during stem development in maize. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 140
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 1-1 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 141
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 431-436 
    ISSN: 0192-253X
    Schlagwort(e): Regulatory mechanisms ; mRNA ; al-dolase ; post-transcriptional control ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The aldolase isozyme family is composed of three members, A, B, and C, which are encoded by separate genes. The proteins are expressed in a tissue-restricted manner during development and in the adult. To elucidate the regulation of aldolose mRNA in the mouse liver, we analyzed its expression by a number of methods including Northern blot, RNA dot blot, and nuclear run-on assays. Our experiments demonstrate that the expression of aldolase A in the liver is primarily regulated by post-transcriptional control. In contrast, we found that changes in the level of aldolase B mRNA are due to changes in the rate of initiation of transcription. In addition, we examined the regulation of aldolase expression in the adult kidney. We found that although the kidney has eight times more aldolase B than the live, the rate of initiation of transcription is similar in both tissues. Also, the rate of initiation of transcription of aldolase A is the same in the adult kidney and liver although there is 40 times more steady state aldolase A mRNA in the kidney than in the liver. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 142
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 2-5 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 143
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 19-24 
    ISSN: 0192-253X
    Schlagwort(e): cAMP ; dephosphorylation ; phos-phatase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The inositolcycle in Dictyostelium discoideum was studied under several conditions both in vitro and in vivo. The results are compared with the inositolcycle as it is known from higher eukaryotes: although there is a strong resemblance both cycles are different at some essential points.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 144
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 6-13 
    ISSN: 0192-253X
    Schlagwort(e): Signal transduction ; G-proteins ; adenylyl cyclase ; gene expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have cloned and characterized three genes (CAR1, CAR2, CAR3) encoding potential cell surface, cyclic adenosine 3′:5′ monophosphate (AMP) receptors from Dictyostelium discoideum. The three proteins are predicted to be substantially similar in amino acid sequence throughout most of their transmembrane (TM) and loop domains but are distinctly different in their carboxyl terminal segments. In addition, all three genes possess an intron which interrupts an equivalent codon of TM3.CAR1 is expressed early in development when the cAMP relay system is being established. As development proceeds multiple size forms of CAR1 RNA are detected which apparently result from differences in their 5′-untranslated regions. Late in development levels of CAR1 RNA decrease. In contrast, CAR2 encodes a single sized RNA which is expressed only during postaggregative development. CAR3 expression is ∼10% of CAR1 during early development, is maximal during tight aggregate formation but declines thereafter. Only one size class of CAR3 mRNA is detected throughout development.Because RNA for each of the three genes is present in postaggregative cells, it was of interest to determine the cell type distribution of each RNA. Gene-specific probes were hybridized to RNAs isolated from cells of Percoll gradient-enriched prespore and prestalk fractions and relative levels of hybridization compared. CAR1 and CAR3 show approximately the same pattern of accumulation; a 3-4 fold enrichment in prestalk cells. CAR2, however, is highly enriched in prestalk cells, more than 10 fold relative to prespore cells.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 145
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 14-18 
    ISSN: 0192-253X
    Schlagwort(e): GDP-dependent ; chemotactic receptor ; CAR-kinase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have examined the phosphorylation of the cyclic adenosine 3′:5′ monophosphate (cAMP) cell surface chemotactic receptor and a 36 kDa membrane-associated protein (p36) in Dictyostelium discoideum. The activity of CAR-kinase, the enzyme responsible for the phosphorylation of the cAMP receptor, was studied in plasma membrane preparations. It was foud that, as in intact cells, the receptor was rapidly phosphorylated in membranes incubated with [γ32P] adenosine triphosphate (ATP) but only in the presence of cAMP. This phosphorylation was not observed in membranes prepared from cells which did not display significant cAMP binding activity. cAMP could induce receptor phosphorylation at low concentrations, while cyclic guanosine 3′:5′ monophosphate (cGMP) could elicit receptor phosphorylation only at high concentrations. Neither ConA, Ca2+, or guanine nucleotides had an effect on CAR-kinase. It was also observed that 2-deoxy cAMP but not dibutyryl cAMP induced receptor phosphorylation. The data suggest that the ligand occupied form of the cAMP receptor is required for CAR-kinase activity. Although the receptor is rapidly dephosphorylated in vivo, we were unable to observe its dephosphorylation in vitro. In contrast, p36 was rapidly dephosphorylated. Also, unlike the cAMP receptor, the phosphorylation of p36 was found to be regulated by the addition of guanine nucleotides. Guanosine diphosphate (GDP) enhanced the phosphorylation while guanosine triphosphate (GTP) decreased the radiolabeling of p36 indicating that GTP can compete with ATP for the nucleotide triphosphate binding site of p36 kinase. This was verified using radiolabeled GTP as the phosphate donor. Competition experiments with GTPγS, ATP, GTP, CTP, and uridine triphosphate (UTP) indicated that the phosphate donor site of p36 kinase is relatively non-sepcific. The mechanism(s) by which GDP functions to alter p36 phosphorylation and the physiological significance of this event are currently under investigation.
    Zusätzliches Material: 4 Ill.
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  • 146
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 25-34 
    ISSN: 0192-253X
    Schlagwort(e): Dictyostelium ; stimulation kinetics ; aggregation-related genes ; prestalk-related genes ; prespore genes ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A compilation of literature data and recent experiments led to the following conclusions regarding cyclic adenosine 3′:5′ monophosphate (cAMP) regulation of gene expression. Several classes of cAMP-induced gene expression can be discriminated by sensitivity to stimulation kinetics. The aggregation-related genes respond only to nanomolar cAMP pulses. The prestalk-related genes respond both to nano-molar pulses and persistent micromolar stimulation. The prespore specific genes respond only to persistent micromolar stimulation.The induction of the aggregation- and prestalk-related genes by nanomolar cAMP pulses may share a common transduction pathway, which does not involve cAMP, while involvement of the inositol 1,4,5-trisphosphate (IP3)/Ca2+ pathway is unlikely. Induction of the expression of prespore and prestalk-related genes by micromolar cAMP stimuli utilizes divergent signal processing mechanisms. cAMP-induced prespore gene expression does not involve cAMP and probably also not cyclic guanosine 3′.5′ monophosphate (cGMP) as intracellular intermediate. Involvement of cAMP-induced phospholipase C (PLC) activation in this pathway is suggested by the observation that IP3 and 1,2-diacylglycerol (DAG) can induce prespore gene expression, albeit in a somewhat indirect manner and by the observation that Li+ and Ca2+ antagonists inhibit prespore gene expression. Cyclic AMP induction of prestalk-related gene expression is inhibited by IP3 and DAG and promoted by Li+, and is relatively insensitive to Ca2+ antagonists, which indicates that PLC activation does not mediate prestalk-related gene expression. Neither prespore nor prestalk-related gene expression utilizes the sustained cAMP-induced pHi increase as intracellular intermediate.
    Zusätzliches Material: 9 Ill.
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  • 147
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 50-53 
    ISSN: 0192-253X
    Schlagwort(e): Dictyostelium ; protein folding ; pepti-dyl-prolyl isomerase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A cDNA encoding a protein homologous to cyclophilins from other species has been isolated from a Dictyostelium discoideum cDNA library. From the deduced amino acid sequence a protein with a molecular mass of 19 kD and 64% identity with human cyclophilin is predicted. Southern blot analysis indicates that there is one cyclophilin gene in the D. discoideum genome. The mRNA is present in all developmental stages.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 148
    ISSN: 0192-253X
    Schlagwort(e): cAMP ; regulatory sequences ; DNA binding proteins ; anti-sense RNA ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The uridine diphosphoglucose pyrophosphorylase (UDPGP1) gene of Dictyostelium discoideum is an excellent marker to study the pathways that control the expression of genes during development. We have previously shown that the UDPGP1 gene is regulated by exogenous cAMP acting on cell-surface cAMP receptors. Various steps in the signal transduction pathway between receptor stimulation and the induction of the gene can now be studied. Induction does not require the synthesis of intracellular cAMP, but does require new protein synthesis. By deletion and transformation with altered genes, two cis-acting sequences that are required for UDPGP1 expression have been identified. A GC-rich palindromic sequence located between -410 and -374 is essential for induction of the gene by extracellular cAMP, but not for its basal expression. A sequence element located between -374 and -337 is required for any basal expression of this gene. When the polarity of the palindromic sequence was reversed such that it resembled the H2K enhancer element, the gene could still be induced by exogenous cAMP. Two DNA binding activities were detected in gel mobility shift assays using a fragment containing both of the regulatory sequence elements of UDPGP1 gene. Transformation with a vector that resulted in the synthesis of anti-sense UDPGP1 RNA led to almost total elimination of the enzyme antigen and no detectable enzyme activity. However, these transformants developed normally, indicating that either UDPGP is not required for development or residual synthesis of UDPGP may be sufficient for normal development.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 149
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 45-49 
    ISSN: 0192-253X
    Schlagwort(e): Polymerase chain reaction ; reversible protein phosphorylation ; signal transduction ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Reversible protein phosphory-lation appears to be important of several stages in the signal transduction pathways in Dictyostelium discoideum. To elucidate its role, we have isolated sequences encoding putative protein kinases and phosphoprotein phosphatases by homology clon- ing using polymerase chain reactions (PCRs). Oli-gonucleotide primers were synthesized for use as forward and reverse primers with their nucleotide sequences deduced from the amino acid sequences of conserved domains of several protein kinases and phosphoprotein phosphatases. The fragments amplified by PCR were cloned, sequenced, and shown to encode parts of five different protein kinases and two phosphoprotein phos-phatases. Several features such as the deduced amino acid sequence homology, location of invariant amino acids, GC content, and the codon usage confirmed that one set of clones encode parts of different protein kinases of Dictyostelium. Two clones derived from phosphoprotein phosphatase primers encode fragments of type 1 and type 2A phosphoprotein phosphatases. Amplified fragments were used to screen a Xgtll bank, and several cDNA clones for protein kinases were isolated. Some of these show differential expression during development or in response to exogenous cAMP.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 150
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 63-64 
    ISSN: 0192-253X
    Schlagwort(e): Development ; differentiation ; gene expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 151
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 54-62 
    ISSN: 0192-253X
    Schlagwort(e): Adenylyl cyclase ; bacteria ; membrane skeleton ; development ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Cyclic adenosine 3′:5′ monophosphate (cAMP) and cell-cell contact regulate developmental gene expression in Dictyostelium discoideum. Developing D. discoideum amoebae synthesize and secrete cAMP following the binding of cAMP to their surface cAMP receptor, a response called cAMP signaling. We have demonstrated two responses of developing D. discoideum amoebae to cell-cell contact. Cell-cell contact elicits cAMP secretion and alters the amount of cAMP secreted in a subsequent cAMP signaling response. Depending upon experimental conditions, bacterial-amoebal contact and amoebal-amoebal contact can enhance or diminish the amount of cAMP secreted during a subsequent cAMP signaling response. We have hypothesized that cell-cell contact regulates D. discoideum development by altering cellular and extracellular levels of cAMP. To begin testing this hypothesis, these responses were further characterized.The two responses to cell-cell contact are independent, i.e., they can each occur in the absence of the other. The responses to cell-cell contact also have unique temperature dependences when compared to each other, cAMP signaling, and phagocytosis. This suggests that these four responses have unique steps in their transduction mechanisms.The secretion of cAMP in response to cell-cell contact appears to be a non-specific response; contact between D. discoideum amoebae and Enterobacter aerogenes, latex beads, or other amoebae elicits cAMP secretion. Despite the apparent similarities of the effects of bacterial-amoebal and amoebal-amoebal contact on the cAMP signaling response, this contact-induced response appears to be specific. Latex beads addition does not alter the magnitude of a subsequent cAMP signaling response. A mutant, DV212, does not alter the magnitude of its cAMP signaling response following bacterial-amoebal contact but alters the magnitude of its cAMP signaling response following amoebal-amoebal contact. Thus, amoebae can differentiate between bead-amoebal contact, bacterial-amoebal contact, and amoebal-amoebal contact.
    Zusätzliches Material: 3 Ill.
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  • 152
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 98-103 
    ISSN: 0192-253X
    Schlagwort(e): Translational control ; ribosomal protein mRNAs ; 5′-untranslated region ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Post-transcriptional controls, including changes in both mRNA translational activity and stability, play an important role in the regulation of ribosomal protein gene expression in developing Dictyostelium discoideum cells. Previously we have shown that the mechanisms which regulate the translational activity of the r-protein mRNAs operate at the level of translational initiation and do not involve changes in polyadenylation or capping. By analysing the translational behavior of chimeric and mutant mRNAs in transformed cells, we have now been able to localize the determinants of translational activity of one of the r-protein mRNAs to the 5′-untranslated region. Although this and other r-protein mRNAs differ strikingly from the Dictyostelium consensus in the region of the initiator AUG codon, we find that improving the match to that consensus does not increase the translational activity of the message in developing cells. Current experiments are designed to determine whether translational regulation is mediated by strong interactions with specific inhibitors or by weak interactions with translational initiation factors.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 153
    ISSN: 0192-253X
    Schlagwort(e): cAMP ; chemotaxis ; transformation ; CAT constructs ; gene regulation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The genes coding for the cyclic nucleotide phosphodiesterase (PD) and the PD inhibitory glycoprotein (PDI) have been cloned and characterized. The PDI gene was isolated as a 1.6 kb genomic fragment, which included the coding sequence containing two small introns and 510 nucleotides of non-translated 5′ sequence. From the deduced amino acid sequence we predict a protein with a molecular weight (MW) of 26,000 that, in agreement with previous data, contains 15% cysteine residues. Genomic Southern blot analysis indicates that only one gene encodes the inhibitor. Northern blot analysis shows a single transcript of 0.95 kb. The PDI gene is expressed early in development with little transcript remaining following aggregation. The appearance of PDI mRNA is prevented by the presence of cAMP, but when cAMP is removed the transcript appears within 30 minutes. When cAMP is applied to cells expressing PDI the transcript disappears with a half-life of less than 30 minutes. The PD gene of D. discoideum is transcribed into three mRNAs: a 1.9 kb mRNA specific for growth, a 2.4 kb mRNA specific for aggregation, and a 2.2 kb mRNA specific for late development. The 2.2 kb mRNA is also specific for prestalk cells, and is induced by differentiation-inducing factor. All three mRNAs contain the same coding sequence, and differ only in their 5′ non-coding sequences. Each mRNA is transcribed from a different promoter, and by using the chloramphenicol acyltransferase gene as a reporter, we have shown that each promoter displays the same regulation as its cognate mRNA. Transformation of wild-type strains with the PD gene causes PD overexpression which accelerates aggregation and blocks subsequent cell differentiation and pattern formation.
    Zusätzliches Material: 8 Ill.
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  • 154
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 113-122 
    ISSN: 0192-253X
    Schlagwort(e): Dictyostelium discoideum ; cyclo heximide ; emetine ; protein synthesis ; mRNA accu mulation ; transcription ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: It has been established previ- ously that the maintenance of expression of pre-spore-specific genes of Dictyostelium discoideum is prevented by the translational inhibitor cyclohex- imide. The drug had no effect upon the level of transcripts of the other genes examined, prestalk-specific or cell type-nonspecific. However, the interpretation of this result is open to question, because of possible nonspecific effects of cyclo-heximide. We have now characterized the cellular specificity and temporal profiles of mRNA accumu- lation of additional Dictyostelium cDNA clones, and have examined other inhibitors of in vivo protein synthesis. Four structurally and mechanistically distinct translational inhibitors each prevented the reaccumulation of prespore transcripts in cyclic AMP-primed, disaggregated amoebae. These results establish the importance of developmental protein synthesis in the accumulation of prespore gene transcripts. Nuclear run-on transcription assays were used to learn whether protein synthesis is required primarily for mRNA synthesis or transcript stability. A transcriptional time course first demonstrated that the abundance of these cell-specific transcripts during development mirrors their rates of synthesis. Significantly, the protein synthesis requirement of the prespore genes examined also occurs at the level of mRNA transcription, implying the existence of one or more developmentally regulated transcriptional activators.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 155
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 123-132 
    ISSN: 0192-253X
    Schlagwort(e): SP60 ; SP70 ; SP96 ; prespore-specific mRNAs ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Genomic clones of the genes coding for the three major spore coat proteins, SP60, SP70, and SP96, were used to measure the accumulation of their respective mRNAs in mutant and wild-type cells allowed to develop under a variety of conditions. These prespore-specific mRNAs were found to be both temporally and quantitatively coordinate under all conditions indicating that they may be subject to identical regulatory processes. Accumulation of the spore coat mRNAs is dependent upon the function of both cAMP receptors and Gα2 proteins during the aggregation stage as well as upon concomitant protein synthesis. When cells are dissociated from aggregates at 10 hr of development and rapidly shaken in 0.1 mM EDTA they form clumps but do not accumulate any of the prespore-specific RNAs assayed. However, if either 0.1 rnM Ca++ or 20 μM cAMP is added to these cells, the spore coat mRNAs accumulate. Lower concentrations of either Ca++ or cAMP had no effect. These results suggest that expression of the spore coat genes normally involves a Ca++ -dependent process, but the Ca++ requirement can be overcome by adding Ca++ high concentrations of exogenous CAMP.Addition of 50 nM DIF to dissociated cell blocks the accu- mulation of the spore coat mRNAs even when cAMP or Ca++ is present. The upstream regions of the spore coat genes were compared to those of another gene, D19, that codes for the prespore-specific protein SP29. Short sequences related to CACCCAC were found at about the same position relative to the transcriptional start sites of these co- ordinately regulated genes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 156
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 133-138 
    ISSN: 0192-253X
    Schlagwort(e): Dictyosteliurn discoideurn ; develop- mentally regulated multigene family ; spore germination ; developmentally regulated genes ; developmentally regulated proteins ; proteins containing internal amino acid repeat ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Two different cDNA clones denoted pT0270-6 and pT0270-11 represent two mRNAs that are developmentally regulated during spore germination in Dictyosteliurn discoideum. The respective mRNAs are found only during early germination and are not present in other stages of growth or multicellular development. Four different genomic clones that hybridize to sequences that are common to both of the 270 cDNA clones were isolated from Dictyostelium libraries and se- quenced. Two are the genes for the two cDNAs, and the other two represent genes that do not seem to be transcribed. All four genomic se- quences possess a very unusual internal feature in the deduced protein sequences composed of a monotonous repeat of the tetrapeptide threonine- glutamic acid-threonine-proline. The other portions of the proteins have no homology among them- selves. The deduced protein corresponding to the 270-6 gene is very similar to avocado (Persea arnericana) cellulase. Since cellulose in the spore wall has to be digested during spore germination this suggests that this protein may function as an endo-( 1,4)-beta-D-glucanase during germination.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 157
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 139-146 
    ISSN: 0192-253X
    Schlagwort(e): Dictyosteliurn ; ras ; run ons ; transcription ; secondary structure ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Transcripts from the Dd ras gene can only be detected once starved cells have begun to aggregate (Reymond et al., Cell 39: 141-148, 1984). We show in this report that the three transcripts which originate from Dd ras during nor- mal development differ in their 5′ ends. In suspen- sion of starved single cells, one major Dd ras RNA accumulates upon addition of CAMP. It seems that the CAMPregulation of Dd ras expression happens both at the transcriptional and post-transcriptional level. An RNA secondary structure present in the 5′ untranslated region of the gene is proposed to be important in this post-transcriptional regulation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 158
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 147-153 
    ISSN: 0192-253X
    Schlagwort(e): Eukaryotes ; vegetative cells ; ras proteins ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Dicfyostelium discoideum, like other eukaryotes, has been shown to express several ras-related genes. Two gene products, Ddras and DdrasG, are highly conserved relative to the human ras proteins. Ddras is expressed at the pseudoplasmodial stage of development, whereas DdrasG is expressed in vegetative cells and during early development. In addition, Dicfyostelium possesses three ras-related genes, SAS1, SAS2 and Ddrap1, whose gene products are only partially conserved relative to those of the ras genes. The expression of these three genes is also developmentally regulated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 159
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 170-170 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 160
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991) 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 161
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 173-187 
    ISSN: 0192-253X
    Schlagwort(e): Melanotic tumor mutations ; cellular defense system ; invertebrate immunity ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Using P element-mediated mutagenesis we have isolated 20 X-linked lethal mutations, representing at least 14 complementation groups, which exhibit melanotic tumor phenotypes. We present the systematic analysis of this interesting group of lethal mutations that were selected for their visible melanotic or immune response. The lethal and melanotic tumor phenotypes of each lethal(1) aberrant immune response (air) mutation are pleiotropic effects of single genetic lesions. Lethality occurs throughout the larval and early pupal periods of development and larval development is extended in some air mutants. The air mutant lethal syndromes include abnormalities associated with the brain, haematopoietic organs, gut, salivary glands, ring glands, and imaginal discs. Additional characterization of the melanotic tumor mutations Tuml and tu(1)Szts have indicated that the melanotic tumor phenotype is similar to that observed in the air mutants. These studies have led to the proposal that two distinct classes of melanotic tumor mutations exist. Class 1 includes mutants in which melanotic tumors result from “autoimmune responses” or the response of an apparently normal immune system to the presence of abnormal target tissues. The Class 2 mutants display obvious defects in the haematopoietic organs or haemocytes, manifested as overgrowth, and the resulting aberrant immune system behavior may contribute to melanotic tumor formation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 162
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 188-195 
    ISSN: 0192-253X
    Schlagwort(e): Protein kinase ; serine-threonine kinase ; cDNA cloning ; gene location ; deficiency mapping ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The Drosophila developmental antigen recognized by the monoclonal antibody F7D6 is expressed in dividing embryonic and imaginal cells but is lost from all differentiating fissues except electrogenic cells of the nervous system and spontaneously contracting muscles. The 63 kDa antigen is associated with the inner surface of plasma membranes and is expressed in several classes of fumorous mutants of Drosophila. The monoclonal antibody was used for immunoprecip-itating the antigen for biochemical characterization and for screening expression vector cDNA libraries. Here we report that this oncodevelopmental antigen is a phosphoprotein and a serine-threonine specific protein kinase. A 1.6 kb cDNA isolated by immunological screening of an ovarian library hybridized to a single band on polytene chromosomes, localizing the gene to 72F on the left arm of the third chromosome. Immunofluorescence assays of deficiency stocks in the region confirmed the location of the gene and identity of the cDNA clone, and mapped the gene between the left breakpoints of Df(3L) st1100.62 and Df(3L) sti7, i.e., between 72F3-7 and 73A1-2. The biochemical and genetic properties indicate that this is a novel growth-related kinase of Drosophila.
    Zusätzliches Material: 6 Ill.
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  • 163
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 196-205 
    ISSN: 0192-253X
    Schlagwort(e): Run-on transcription ; developmentally regulated gene expression ; follicle cell nuclei ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: To determine the relative roles of transcriptional and post-transcriptional events in establishing the temporal pattern of chorion gene expression in Drosophila, we have examined chorion gene transcription, RNA accumulation, and protein synthesis in follicles of selected pre-early- and late-choriogenic stages. Chorion gene transcription was assayed in follicle cell nuclei by nuclear run-on reactions. For the s 15, s 16, s 18, s36, and s38 chorion genes, the periods of intense transcription are as predicted from the dynamics of RNA accumulation and protein synthesis, indicating that these genes are primarily regulated at the transcriptional level. In contrast, gene s19 appears subject to post-transcriptional control at stage 14, when transcription rates are substantially higher than predicted from the observed RNA levels.Transcription of regions between the clustered and tandemly oriented chorion genes was also examined. In contrast to many RNA polymerase II transcribed genes, for the s18 and s36 chorion genes run-on transcription appears to terminate within about 100 base pairs downstream of the polyadenylation sites, corroborating previous reports based on electron microscopy of s36 [Osheim et al., EMBO J 5:3591-3596, 1986].
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 164
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 206-211 
    ISSN: 0192-253X
    Schlagwort(e): Homeobox ; viscera ; phalloidin ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: H2.0, a homeobox gene identified by homology to the Sex combs reduced homeobox of Drosophila, is expressed in all the cellular precursors of the visceral musculature. By analogy to the essential function of most other known homeobox genes in determining the fate of cells where they are expressed, we hypothesized that mutation of H2.0 would disrupt gut muscle development. In this paper, we show that a small deletion, which eliminates H2.0, has no detectable effect on normal gut morphogenesis, visceral muscle actin organization, or larval peristalsis.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 165
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 212-218 
    ISSN: 0192-253X
    Schlagwort(e): DNA regulatory elements ; transfection-competition experiments ; transcription ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A transient expression assay was used to localize cis-acting DNA regulatory elements near the Drosophila heat shock protein (hsp) 22 gene, that are involved in heat shock expression and in ecdysterone-induced expression. The results identify a region between positions -320 and -232 that is essential for ecdysterone control, but not for heat-induced expression, and a sequence between -199 and -56, which, when deleted, leads to the loss of heat shock induction. To investigate the function of these DNA sequences, transfection-competition experiments were carried out. The evidence suggests that the DNA regulatory sequences identified by transient expression studies contain binding sites for transacting transcription factors.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 166
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 219-225 
    ISSN: 0192-253X
    Schlagwort(e): Glycerol-3-phosphate dehydrogenase ; tissue-specific expression ; isozymic composition ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The tissue-specific expression and isozymic composition of Drosophila sn-glycerol-3-phosphate dehydrogenase (GPDH) (EC 1.1.1.8) have been determined for a high-activity control line and two variant lines that alter either the temporal or systemic expression of GPDH through a reduction in rates of polypeptide synthesis. The temporal variant exhibits a reduction in enzyme levels in all larval tissues and in the adult abdomen, while levels of activity in the adult thorax are equal to the control line. Isozymic analyses of these tissues demonstrate that it is the GPDH-3 species that is reduced in a temporal and tissue-specific manner. In contrast, the systemic variant demonstrates a uniform reduction of all isozymic species in each tissue and developmental stage. Analyses of the tissues of F1 hybrid offspring of each variant line and appropriately marked electrophoretic variants demonstrate that the tissue-specific effects observed are due to cis-acting elements that are tightly linked to the structural gene.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 167
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 253-253 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 168
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 299-307 
    ISSN: 0192-253X
    Schlagwort(e): β-lactoglobulin ; transgenic ; mammary gland development ; milk protein gene expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: β-Lactoglobulin (BLG) is the most abundant whey protein in sheep milk but it is not present in mouse milk. We have previously shown that transgenic mice carrying the BLG gene express it specifically in the mammary gland and secrete BLG into milk at high concentrations. Here we demonstrate that BLG transcription is correctly initiated in mice and that BLG synthesis is restricted to the secretory epithelial cells of the mammary gland. We have also determined the temporal pattern of milk protein gene expression and find that the BLG transgene is regulated coordinately with mouse β-casein and that the patterns of regulation of BLG in mouse and sheep share some similarities.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 169
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 308-317 
    ISSN: 0192-253X
    Schlagwort(e): Connexin32 ; connexin43 ; brain ; mRNA ; protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The timing of appearance of mRNAs encoding gap junction proteins was examined during development of the rat and mouse brain. Complementary DNAs (cDNAs) specific for the mRNA for the liver-type gap junction protein, connexin32, and the heart-type gap junction protein, connexin43, were used to probe Northern blots of total RNA isolated from the forebrain and hindbrain of mice and rats at various times before and after birth. Prior to postnatal day 10, connexin32 mRNA is detectable only at low levels. By postnatal days 10 to 16, a sharp increase occurs in the level of this mRNA. This increase is detectable first in the hindbrain, and subsequently in the forebrain. In contrast, connexin43 mRNA is readily detectable at birth, and the level of this mRNA also increases during subsequent development. The developmental appearance of the gap junction proteins, connexin32 and connexin43, was similar to that of their respective mRNAs. These results indicate that the genes encoding connexin32 and connexin43 are differentially expressed during neural development.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 170
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 349-361 
    ISSN: 0192-253X
    Schlagwort(e): Drosophila ; Psc gene ; polycomb group gene ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The Posterior Sex Combs (Psc) gene of Drosophila is a member of the Polycomb (Pc) group of transregulatory genes. Previous analyses of the function of this gene in Drosophila em-bryogenesis have been hampered by the lack of a null mutation. We recently isolated a mutation that deletes the 5′ end of the Psc gene. This allele appears to be a null mutation, and we have used it to determine the Psc zygotic null phenotype and to look at the interactions of a null allele of Psc with five other Pc group mutations. We find evidence for transformations along both the anterior-posterior and dorsal-ventral axes in embryos of a variety of genotypes that include a null mutation in Psc. The phenotypes of embryos that are doubly mutant for a null allele of Psc and a mutation in a second Pc group gene show dramatic synergistic effects, but in their specifics they are dependent on the identify of the second Pc group gene. This is different from the relatively uniform phenotypes seen among double mutants that contained the allele Psc1, which has both gain and loss of function properties. The differences in the phenotypes of the doubly mutant embryos allow us to eliminate one class of molecular models to explain the dramatic synergism seen with mutations in this group of genes.
    Zusätzliches Material: 5 Ill.
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  • 171
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 362-370 
    ISSN: 0192-253X
    Schlagwort(e): Aging ; genetics of aging ; biomarkers ; free radicals ; catalase ; Drosophila ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A long-lived (L) strain of Drosophila melanogaster, derived from a normal-lived (R) strain by artificial selection, has a significantly different adult longevity. Previous work has shown that (1) the two strains age in the same manner, (2) the major genes responsible for much of the L strain's extended longevity are located on the 3rd chromosome, and (3) the extended longevity phenotype is significantly modulated by the larval environment. In this report, we investigate the resistance of the L and R strains to the lethal effects of dietary paraquat. We show that, within the limitations of our described chromosomal and environmental manipulations, the extended longevity phenotype always accompanies the phenotype of elevated paraquat resistance. In addition, reversed selection applied to the L strain results in the simultaneous decrease of both life span and paraquat resistance. Thus, the presence or absence of the latter phenotype may be used as a bioassay for the presence or absence of the extended longevity phenotype, without any necessary implication of causality. Use of this bioassay should greatly speed up the genetic analysis of this system by allowing us to identify long-lived animals at a young age. Finally, we show that the age-related loss of elevated paraquat resistance in both strains precedes all the other age-related functional decrements which we have previously noted in this system.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 172
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 380-380 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 173
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991) 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 174
    ISSN: 0192-253X
    Schlagwort(e): Genetic ablation ; congenital abnormalities ; transgenic mice ; cell death ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Transgenic mice were used in an experiment that was designed to serve as a model of a possible approach to reducing the amount of carcass fat in meat animals. The objective was to reduce the number of adipocytes in transgenic mice thereby restricting the capacity to accumulate lipid. Our approach employed the technique of genetic ablation. The promoter for the adipocyte lipid binding protein gene was used in an attempt to direct expression of diphtheria toxin genes specifically to adipocytes. Three diphtheria toxin genes were used; they encode, respectively, an extremely cytotoxic wild type toxin, a less toxic attenuated toxin, and a nonfunctional toxin. While it was not possible to accurately assess effects of the transgenes on lipid accumulation, several informative observations were noted. A large percentage of transgenic founder mice that harbor either wild type or attenuated toxin genes are morphologically abnormal, die as neonates, or exhibit reproductive abnormalities including sterility or failure to transmit the transgene to offspring. In contrast, mice that harbor the nonfunctional toxin gene or are nontransgenic rarely have these same abnormalities. These results suggest that the trans-genic mice are expressing the transgenes in cells other than adipocytes and that the aberrant production of functional toxin is responsible for the congenital abnormalities. The production of morphological and reproductive abnormalities in transgenic animals should be useful for investigating normal developmental processes.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 175
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 381-381 
    ISSN: 0192-253X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 176
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 12 (1991), S. 65-77 
    ISSN: 0192-253X
    Schlagwort(e): Histones ; nucleosomes ; micrococcal nuclease digestion ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Micrococcal nuclease digestion of chromatin from growing cells reveals a structural organization which differs for genes transcribed at diverse rates. The late cAMP dependent prespore genes which are not transcribed in growing cells are found in growing cells in a regular nucleosomal repeat with an average spacing of 168 nucleotides. By contrast genes expressed at a low level in growing cells show an irregular pattern of bands with an average distance between bands of 80 nucleotides. The sizes of the bands generated from the transcribed genes are consistent with the concept that transcription results in the loss of the linker region histone H1 with concomitant sliding of nucleosomes to generate close packed (“slipped”) di, tri, and tetra nucleosomes lacking the linker region. Further analysis of dinucleosomes released by micrococcal nuclease digestion reveals that transcriptionally active genes are found associated with dinucleosome species which may be lacking histone H1. The length of DNA protected by these dinucleosomes is heterogeneous, ranging from 250 to 300 nucleotides.Methodology is described which has been adapted to allow two dimensional hybridization mapping of nucleoprotein complexes on single copy Dictyostelium genes.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 177
    ISSN: 0192-253X
    Schlagwort(e): Developmental regulation ; ribosomal protein genes ; spore germination ; promoter structure ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have examined the expression and structure of vegetative specific genes belonging to the V and H gene classes. Both classes of genes are deactivated at the onset of development by a reduction in the rate of transcription. Thus, the genes must be reactivated when the terminally differentiated spores germinate and the resulting amebae return to the vegetative state. During germination, activation of expression of most members of the V gene class was found to parallel the emergence of amaebae from the spore coats. The activation of the V genes did not occur when protein synthesis was inhibited. The timing of activation of the H genes was more heterogeneous and did not parallel emergence. H gene activation occurred even when protein synthesis was inhibited. V4 was found to be the only vegetative specific gene that was responsive to the presence of bacteria. V4 expression was induced by 25-100 fold via transcriptional activation when bacteria were added to amebae growing axenically. Isolation and sequence analysis of the corresponding genomic clones revealed that two V genes, V18 and V1, encode ribosomal proteins. Promoter analysis has delineated the sequences necessary for expression and regulation for several of the V and H genes. In all cases, expression was determined by sequences within the first several hundred base pairs of the transcription start site. For V18 and V14, a positive constitutive element was identified in addition to the sequences involved in regulation. Finally, all of the characterizations and findings are discussed in terms of postulated models for V and H gene expression and regulation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 178
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 73-78 
    ISSN: 0749-503X
    Schlagwort(e): Schizosaccharomyces ; fission yeast ; nDNA/nDNA optical reassociation ; taxonomy ; phylogenetic relatedness ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The genus Schizosaccharomyces comprises a small, somewhat heterogeneous group of yeast species which have in common a unique mode of vegetative reproduction by cross-wall formation without constriction as well as a certain degree of osmophilia, most strains having been isolated from habitats of high sugar concentration. This study evaluated inter- and intraspecific relationships utilizing nDNA/nDNA optical reassociation and by the analysis of physiological profiles of several strains of each species. Results demonstrate that the genus should be divided into three species: Schiz. japonicus, Schiz. octosporus and Schiz. pombe.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 179
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 51-60 
    ISSN: 0749-503X
    Schlagwort(e): ARS elements ; plasmid ; mitochondrial DNA ; yeast ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The insert-containing, non-canonical ori 6 region of yeast mitochrondrial DNA of Saccharomyces cerevisiae was dissected into 15 different segments that were ligated to the integrative yeast vector YIp5. Six recombinant plasmids exhibited replicative ability in yeast and carried consensus sequences similar to the previously described 11 bp motifs active as autonomous replication sequences (ARS). In addition, all active constructions carry one or more of the characteristic GC-rich domains A, B or C present in the ori 6 region, thus confirming and expanding the study of Blanc (Gene 30 (1984) 47-61) with the canonical ori 5. Also a new transcriptional origin is activated in the ori 6 region, apparently circumventing a disruption by insertion of a GC-rich sequence that, in this ori, removes the mitochondrial promoter usually present next to the Celement. The ARS-positive constructions correspond to the retained segments of spontaneous well-characterized suppressive or neutral petite genomes that contain segments of the ori sequence.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 180
    ISSN: 0749-503X
    Schlagwort(e): Superoxide dismutase ; brewing yeast ; catalase ; oxygen toxicity ; aerobic transition ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The physiological effects on brewing yeast, growing in semi-defined wort medium, of a sudden transition from aerobiosis to anaerobiosis were studied. Two yeast strains were examined, used for ale and lager fermentations respectively. The reverse transition (from anaerobiosis to aerobiosis) was also examined. Transitions were applied by changing the sparging gas during growth or in stationary phase, and the effects on the specific activities of certain key enzymes and on the viability of the cultures were examined.Neither type of transition led to significant changes in growth rate, the rate of ethanol production or the specific activities of alcohol dehydrogenase and pyruvate decarboxylase. The most significant change was in the specific activity of CuZn-superoxide dismutase, which showed a rapid increase in activity on transition from anaerobiosis to aerobiosis, and a decrease in activity on the reverse transition. Catalase activity in the ale yeast generally followed that of CuZn-superoxide dismutase, whereas in the lager yeast it remained unchanged by the transitions. The transition from anaerobiosis to aerobiosis caused increases in citrate synthase and Mn-superoxide dismutase, though only after a significant lag period. Aerobic to anaerobic transitions caused a decrease in Mn-superoxide dismutase activity, while citrate synthase remained unchanged.Anaerobically grown cells showed a rapid loss in viability on exposure to oxygen (5-7% in the first hour), while aerobically grown cells were unaffected. When anaerobically grown cells were exposed to 0·25 mM-potassium superoxide, there was an 8% loss of viability within 10 min, whereas aerobic cells were not affected.It is concluded that the toxic effect of oxygen is due to superoxide (or a species derived from it) and that the CuZn-superoxide dismutase (but not the Mn-isoenzyme) plays a role in protecting the cells. The de novo synthesis of the CuZn-enzyme is not always rapid enough to confer full protection.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 181
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 219-228 
    ISSN: 0749-503X
    Schlagwort(e): Protein kinase ; Saccharomyces cerevisiae ; yeast ; protein phosphorylation ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The catalytic domain (30 kDa) of all protein kinases can be aligned for maximum homology, thereby revealing both invariant and highly conserved residues. The KIN1 locus from Saccharomyces cerevisiae was isolated by hybridization to a degenerate oligonucleotide encoding the conserved protein kinase domain, DVWSFG. The predicted amino acid sequence revealed significant homology to the catalytic domain of protein kinases. Using antibodies raised against a bacterial LacZ/KIN1 fusion protein, we have identified by immunoprecipitation the yeast KIN1 gene product as a 145 000 dalton protein (p145KIN1). In exponentially growing yeast cells, the KIN1 protein is phosphorylated primarily on serine residues. The gene product of KIN1 was shown to be a serine/threonine-specific protein kinase in immune complexes, as detrmined by the transfer of label from [γ-32P]ATP to either pp145KIN1 or to an exogenously added substrate, α-casein. The optimal metal ion concentration in this assay was 20 mM-MnCl2. Subsequent phosphoamino acid analysis of the radiolabelled product, pp145KIN1, demonstrated that this autophosphorylation was specific for serine/threonine residues. There is no apparent difference between wild-type cells and cells containing a disrupted KIN1 gene. The biochemical characterization of protein kinases in simple eukaryotes such as yeast will aid us in detrmining the role of phosphorylation in cellular growth and physiology.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 182
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 489-494 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; yeast ; unsaturated fatty acids ; phosphatidylinositol ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Saccharomyces cerevisiae was grown anaerobically in media supplemented with myritoleic 14:1(9c), palmitoleic 16:1(9c), oleic 18:1(9c), linoleic 18:2(9,12c), γ-linolenic 18:3(9,12,15c) or eicosenoic 20:1(11c) acid. Cells from exponential-phase cultures contained approximately the same proportions of the major phospholipid classes, namely phosphatidycholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine, the greatest differences being detected in cells grown in the presence of 14:1(9c) or 20:1(11c) acids. The extent to which phospholipids from cells were enriched with residues of the exogenously supplied acid varied from 52% in cells grown in the presence of 14:1(9c) acid to 13% in cells grown in media supplemented with 20:1(11c) acid. Analysis of the fatty-acyl composition of the four major phospholipid classes revealed that the degree of unsaturation varied considerably in three of the classes, while phosphatidylinositol conserved a high degree of saturation. The possible significance of the latter finding in relation to the physiological role of phosphatidylinositol in the plasma membrane is discussed.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 183
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991) 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 184
    ISSN: 0749-503X
    Schlagwort(e): Trichosporon cutaneum ; auxotrophic mutants ; UV-mutagenesis ; transformation of spheroplasts ; sib-selection ; integration ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A transformation system for the filamentous yeast Trichosporon cutaneum based on auxotrophic markers is presented and techniques for the induction, isolation and characterization of mutants are described. A number of auxotrophic mutants were isolated and characterized by using biosynthetic precursors and/or inhibitors. A mutant unable to grow in the presence of ornithine could be complemented successfully in spheroplast transformation experiments using the cloned Aspergillus nidulans ornithine transcarbamoylase gene (argB gene) as selection marker with an efficiency of 5-100 transformants per μg of DNA. In these transformants the heterologous argB gene was present in multiple tandem copies and the transforming DNA was found to remain stable after more than 50 generations in non-selective media. The same mutant could be complemented by a T. cutaneum cosmid gene library and a complementing cosmid was subsequently isolated from this library by a sib-selection strategy. This cosmid transformed. T. cutaneum spheroplasts with an efficiency of 50-200 colonies per μg of DNA. Southern blot analyses were consistent with the view that the transforming sequences became stably integrated into the host genome at the homologous site.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 185
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; trehalose metabolism ; catabolite inactivation and repression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: During diauxic growth of yeast in glucose-rich medium, the accumulation of trehalose started well after complete exhaustion of glucose from the medium. The accumulation of the disaccharide was concomitant with a resumption of cell growth on the ethanol accumulated in the medium, but not with a degrdation of glycogen which occurred as soon as glucose had been consumed. In contrast, in a mutant deficient in phosphoenlpyruvate carboxykinase, the synthesis of trehalose coincided exactly with the degradation of glycogen. Upon inoculation of stationary phase wild-type cells into a glucose medium, the activites of trehalose-6-phosphate (Tre6P) synthase and Tre6P phosphatase dropped in parallel to reach only 15% of their initial values after 3 h, and only recovered their original values as cell re-entered staionary phase. In the presence of cycloheximide, the decrease in Tre6P synthase and Tre6P phosphatase activities was restricted to 50-60%, the remaining decrease being inhibited by the drug. Furthermore, the reappearance of the enzyme activities following transfer of cells to an acetate medium was blocked by cycloheximide. It was also shown that loss of activity of these two enzymes required a combination of metabolizable sugars together with a nitrogen source. Low activities of Tre6P synthase and Tre6P phosphatase were measured in mutants with increased adenylate cyclase activity (RAS2ala18val19 mutants). Moreover, derepression of these enzymes at the approach of stationary phase was prevented in a pde2 mutant when it was cultivated in the presence of exogenous cyclic nucleotide. The mechanism of this effect is not clear, but may involve a transcriptional regulation by cAMP of the genes encoding these proteins.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 186
    ISSN: 0749-503X
    Schlagwort(e): Shuttle vectors ; yeast replication origin ; mitotic stability ; pUC19 plasmid ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We describe a set of replicative, integrative and single-stranded shuttle vectors constructed from the pUC19 plasmid that we use routinely in our experiments. They bear a yeast selectable marker: URA3, TRP1 or LEU2. Replicative vectors carrying different yeast replication origins have been constructed in order to have plasmids based on the same construction with a high or low copy number per cell and with different mitotic stabilities. All the vectors are small in size, provide a high yield in Escherichia coli and efficiently transform Saccharomyces cerevisiae. These plasmids have many of the unique sites of the pUC19 multicloning region and many of them allow for the screening of plasmids with an insert by alpha-complementation. The nucleotide sequence of each of them is completely known.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 643-650 
    ISSN: 0749-503X
    Schlagwort(e): yeast ; Saccharomyces cerevisiae ; protein secretion ; SEC1 ; nucleotide sequence ; amino acid sequence ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The SEC1 gene of yeast Saccharomyces cerevisiae was cloned by complementing the temperature-sensitive mutantion of sec1-1 at 37°C, and its nucleotide sequence was determined. SEC1 is a single copy gene and encodes a protein of 724 amino acids and 83,490 daltons with a predicted pI value of 6·11. Hydrophobicity plotting showed no clearly hydrophobic regions suggesting a soluble nature for the protein. Amino acid sequence comparisons revealed no obvious homologies with the proteins in the SWISSPROT databank. Two consensus sequences for the cdc2 encoded protein kinase recognition site were revealed within Sec1p. The codon usage suggests a low expression level for SEC1. The 5′ non-translated region contains two TATA-like sequences at -52 and -215 nucleotides from the translation start site. Two potential regulatory sequences for DNA binding proteins were found in the non-coding 5′ region: a HAP2/HAP3 consensus recognition sequence at nucleotide -154 and a BAF1 consensus recognition sequence at nucleotide -136. The SEC1 specific probe detected a 2400 nucleotides long transcript, which was in reasonable agreement with the 2172 nucleotides long open reading frame.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 188
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 189
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 525-531 
    ISSN: 0749-503X
    Schlagwort(e): Fission yeast ; aminopeptidase ; mutant ; peptidase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A mutant strain of the fission yeast Schizosaccharomyces pombe defective in aminopeptidase I was isolated by screening for lack of activity against the chromogenic substrate lysine-β-naphthlamide in isolated colonies. Tetrad dissection of sporulated diploids heterozygous for the wild-type and mutant allele resulted in a 2:2 segregation of mutant and wild-type phenotype indicating a single chromosomal gene mutation. Gene dosage experiments indicated that the mutation might reside in the structural gene of aminopeptidase I. No vital consequences of aminopeptidase I deficiency on cell life and sporulation could be detected. However, the enzyme seems to be involved in protein degradation under conditions of nutrient deprivation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 190
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 559-574 
    ISSN: 0749-503X
    Schlagwort(e): Flocculation ; yeast ; lectin ; receptor structure ; Flo1 ; phenotype ; NewFlo phenotype ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Flocculation characteristics of 42 flocculet strains of Saccharomyces cerevisiae were examined. Two entirely distinct ‘lectin-like’ mechanisms of flocculation were distinguished by sugar, salt, and low pH inhibitions, protease sensitivity, and selective expression of flocculation. One group, termed Flo1 phenotype, was inhibited by mannopyranoses and contained all strains bearing known genes affecting flocculation. The other group, termed NewFlo phenotype, contained the majority of brewery ale strains and was inhibited by manno- and glucopyranoses. Detailed sugar-inhibition work revealed the probable receptor identity of both Flo1 and NewFlo flocculation, as being non-reducing termini of α-(1-3)-linked mannan side branches, two or three mannopyranose residues in length.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 191
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 607-608 
    ISSN: 0749-503X
    Schlagwort(e): 5-fluoro-orotic acid ; ura3- mutations ; nitrogen catabolite repression ; Saccharomyces cerevisiae ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The use of proline as a nitrogen soucre causes hypersensitivity to 5-fluoro-orotic acid (5FOA) and allows up to 40-fold less of this drug to be used to select for the loss of URA3 function in Saccharomyces cerevisiae. 5FOA hypersensitivity is presumably due to the absence of nitrogen catabolite repression when proline is substituted for (NH4)2SO4 as a nitrogen source. There are two constraints to the use of the proline-5FOA combination: (1) S288c genetic background strains are hypersensitive to 5FOA when grown in proline as a nitrogen source but at least one other genetic background is resistant to low levels of 5FOA under these conditions. (2) The addition of some nutritional supplements confers phenotypic resistance to the 5FOA-proline combination.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 192
    ISSN: 0749-503X
    Schlagwort(e): Chromosome III ; sequencing ; gene disruption ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have determined the nucleotide sequence of a segment of chromosome III contained in the right part of the lambda PM3270 clone, for a total of 8824 bp. This sequence contains an unusual long open reading frame, YCR601, of 6501 bp that encodes for a protein of 2167 amino acids that show no homology with other known proteins. YCR601 was disrupted by internal deletion and insertion of LEU2 gene and is a non-essential gene, however it is transcribed during vegetative growth yielding a polyadenylated mRNA of approximately 7 kb.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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