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  • 101
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    Current genetics 8 (1984), S. 29-32 
    ISSN: 1432-0983
    Keywords: Antisuppression ; Suppression ; tRNA ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of a previously isolated antisuppressor mutation from bakers' yeast, that reduced the efficiency of the tyrosine-inserting ochre suppressor, SUP7-o, on other tyrosine-inserting ochre suppressors has been determined. As expected, the antisuppressor mutation, mod5-1, restricted the capacity of all eight tyrosine-inserting ochre suppressors to suppress nonsense mutations. Based on the suppression of five ochre alleles in the presence of mod5, the eight class I suppressors can be grouped into three subclasses. The most efficient subclass had only one member, SUP4-o. Members of the second group included SUP2-o, SUP3-o, SUP7-o, and SUP8-o. The third and least efficient subclass included SUP5-o, SUP6-o, and SUP1 1-o. These differences in efficiencies are a function of the relative expression of the eight genes encoding tRNATYR.
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  • 102
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    Current genetics 8 (1984), S. 85-92 
    ISSN: 1432-0983
    Keywords: Chromosome map ; Yeast ; Schizosaccharomyces pombe ; Gene conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genetic map of the nuclear genome of the fission yeast Schizosaccharomyces pombe has been extended by mitotic and meiotic mapping data. A total of 158 markers are now assigned to the three linkage groups known in this organism, and 118 of them have been located on the corresponding chromosome map. Chromosome II and III each consist of one linkage group. There is some indication that the two large fragments which define chromosome I are meiotically linked, but the linkage observed is significant at the P = 0.05 level only. The length of the map is at least 1,700 map units, corresponding to an average of about 8 kilobases per map unit. The latter figure is comparable to the one obtained for intragenic recombination in the sup3 gene (Hofer et al. 1979). The basic frequency of gene conversion as measured for 21 genes varies according to a distribution of Poisson (with a modal value of 0.6% conversion per meiosis and per gene), in sharp contrast with Saccharomyces cerevisiae (Fogel et al. 1980) and Ascobolus immersus (Nicolas 1979). This may reflect the rarity of gene or region-specific rec alleles in S. pombe and may be related to the homothallism of this organism.
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  • 103
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    Current genetics 8 (1984), S. 353-358 
    ISSN: 1432-0983
    Keywords: Hygromycin B ; Yeast ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Saccharomyces cerevisiae is normally sensitive to the drug hygromycin B; a hygromycin B concentration of 200 µg/ml in agar plates is sufficient to completely inhibit growth. We constructed yeast-E. coli bifunctional plasmids which confer hygromycin B resistance to Saccharomyces cerevisiae. Promoters and amino terminal coding regions of a heat shock gene, a heat shock cognate gene, and the phosphoglycerate kinase gene from yeast were fused to a bacterial hygromycin B resistance gene. In all three cases, yeast cells containing plasmids with the hybrid hygromycin B resistance gene were resistant to high levels of the drug. Yeast cells containing these plasmids can also be directly selected after transformation by using hygromycin B. The intact bacterial hygromycin B resistance gene and the kanamycin resistance gene from Tn903 were also tested in yeast for their ability to confer resistance to hygromycin B and G418. The intact bacterial genes were not effective in conferring drug resistance to yeast cells.
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  • 104
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    Current genetics 7 (1983), S. 85-92 
    ISSN: 1432-0983
    Keywords: Yeast ; RAD52 ; Cloning ; S1 and BAL31 Deletions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The RAD52 gene of Saccharomyces cerevisiae has previously been shown to be involved in both recombination and DNA repair. Here we report on the cloning of this gene. A plasmid containing a 5.9 kb yeast DNA fragment inserted into the BamH1 site of the YEp13 vector has been isolated and shown to complement the X-ray sensitive phenotype of the rad52-1 mutation. The rad52-1 cells containing the plasmid form larger colonies than similar cells having lost the plasmid. This plasmid has been shown not to complement either the U.V. sensitivity or the recombination defect of the E. coli recA mutation. From the insert various fragments have been subcloned into the YRp7 and YIp5 vectors. Integration events of two of the subclones have been genetically mapped to the chromosomal location of RAD52, indicating that the structural gene has been cloned. A 1.97 kb BamH1 fragment subcloned into YRp7 in one orientation complements the rad52-1 mutation, while the same fragment in the opposite orientation fails to complement. Various other subclones indicate that a BglII site, within the BamH1 fragment, is in the RAD52 gene. This BglII site has been deleted by Sl-nuclease digestion and the resulting deletion inactivates the RAD52 gene. BAL31 deletions from one end of a 1.9 kb Sal1-BamH1 fragment have been isolated; up to 0.9 kb can be deleted without loss of RAD52 activity, indicating that the RAD52 gene is approximately 1 kb or less in length.
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  • 105
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    Current genetics 7 (1983), S. 235-237 
    ISSN: 1432-0983
    Keywords: DNA replication ; Shuttle vectors ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic segregation of three 2 μm-pBR322 chimaeric plasmids (YEp6, YEp21, and YEp24) was studied in yeast. Each displayed a characteristic rate of loss: YEp6 was lost at approximately twice the rate of YEp21 and YEp24. The loss rates were not significantly increased when two chimaeric plasmids were coresident, nor was the endogenous 2 μm plasmid itself displaced. Therefore these plasmids appear to be compatible in yeast.
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  • 106
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    Current genetics 8 (1984), S. 69-76 
    ISSN: 1432-0983
    Keywords: Yeast ; Ethidium bromide ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ethidium bromide was found to inhibit nuclear and mitochondrial DNA synthesis during meiosis which resulted in the inhibition of meiotic gene conversion and sporulation and was also lethal. Protection from the effects of ethidium bromide on meiotic gene conversion and survival was found to coincide with DNA synthesis, but it is possible that protection from sporulation inhibition occurs only later in meiosis.
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  • 107
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    Current genetics 8 (1984), S. 333-340 
    ISSN: 1432-0983
    Keywords: polA+ ; DNA polymerase I ; Cloning ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The E. coli polA + gene has been subcloned from a specialised λ transducing phage onto a low copy number plasmid. Plasmid-encoded DNA polymerase I was synthesised at 2 to 3 times the wild-type E. coli level, and was biochemically indistinguishable from chromosomally-encoded protein. It was able to counteract the radio sensitivity of polA1, polAex1, polAex2 and polA12 mutants, but no complementation of polA107 mutants occurred, even though the plasmid polA+ gene was expressed. S. cerevisiae ars-1 or 2 μ replicative sequences were introduced into the polA+ plasmid. Transformation of yeast with these constructs increased total DNA polymerase levels 2–20 times, depending upon assay conditions. The additional activity was discriminated from yeast DNA polymerases by its ability to use low concentrations of substrate, by its resistance to chemical inhibition, and by co-electrophoresis with pure DNA polymerase I and its proteolytic fragments. The polA+ gene was expressed in yeast without the aid of yeast promotor sequences. However, deletion of cloned DNA more than 99 base pairs in front of the structural gene prevented expression in yeast but not in E. coli, indicating that the two organisms use different sequences for expression of the plasmid polA+ gene.
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  • 108
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    Current genetics 8 (1984), S. 471-475 
    ISSN: 1432-0983
    Keywords: β-Glucanase ; Expression ; Heterologous DNA ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A cloned endo-1,3-1,4-β-glucanase gene from the Gram-positive bacterium B. subtilis has been located by deletion analysis on a 1.4 kb PvuI-ClaI DNA fragment. This gene has been sub-cloned in the yeast LEU2 vector pJDB207 to produce a hybrid plasmid designated pEHB9. pEHB9 has been transformed to S. cerevisiae and shown to direct the synthesis of an endo-1,3-1,4-β-glucanase in yeast. The β-glucanase activity was low and could only be detected in crude cell extracts of yeast harbouring pEHB9.
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  • 109
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    Current genetics 8 (1984), S. 559-566 
    ISSN: 1432-0983
    Keywords: DNA repair ; Saccharomyces cerevisiae ; Cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three overlapping plasmids were isolated from a YEp24 library, which restore Rad+ functions to rad6-1 and rad6-3 mutants. Different subclones were made and shown to integrate by homologous recombination at the RAD6 site on chromosome VII, thus verifying the cloned DNA segments to be the RAD6 gene and not a suppressor. The gene resides in a 1.15 kb fragment, which restores Rad+ levels of resistance to U.V., MMS and γ-rays to both rad6-1 and rad6-3 strains. It also restores sporulation ability to rad6-1 diploids. Integrative deletion of the RAD6 gene was shown not to be completely lethal to the yeast. Our results suggest that the RAD6 gene has some cell cycle-specific function(s), probably during late S phase.
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  • 110
    ISSN: 1432-0983
    Keywords: α-Pheromone-inactivating glycoproteins ; bar1-1 ; Barrier proteins ; Purification ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two kinds of a-mating-type-specific proteins inactivating α pheromone (α factor) were purified from heat shock extract of MATa cells. Their molecular weights were estimated to be 400,000 and 200,000 by gel filtration. Both proteins were detected in MATa SST1 cells but not in MATα SST1, MATa sst1-1 and MATa/MATα SST1/SST1 cells. In addition, the proteins were detected in matα2-1 SST1 cells but not in matα1-2 SST1 cells. From these results, it is concluded that these proteins are synthesized under the control of the SST1 gene and responsible for the Barrier action of MATa cells. The relationship of these proteins to the secreted Barrier protein having a higher molecular weight is discussed.
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  • 111
    ISSN: 1432-0983
    Keywords: Regulation ; Urea ; Catabolism ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Urea amidolyase and the high affinity urea uptake system are induced by allophanate. durM − and durL − recessive mutations, which are easily obtained, totally prevent this induction. They are not linked to each other nor to the concerned structural genes. Despite an intensive hunt, no mutation of repressor or classical operator type has been selected. We conclude that urea amidolyase and urea uptake induction involves at least two positive elements coded for by the durM and durL genes.
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  • 112
    ISSN: 1432-0983
    Keywords: Yeast ; Catalase ; Trehalose ; Glycogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutations at the GLC1 locus in Saccharomyces cerevisiae result in a major deficiency in synthesis of catalase T, but do not affect catalase A. Three independent glc1 mutations were shown to have the same pleiotropic phenotype: catalase T deficiency, defective glycogen synthesis and defective trehalose accumulation. These three deficiencies appear to be determined by a single, nuclear gene. The possibility that glc1 mutations alter a protein kinase is considered.
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  • 113
    ISSN: 1432-0983
    Keywords: Arginine catabolism ; Regulation ; Ornithine transaminase ; Double induction ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Yeast ornithine transaminase is known to be induced by arginine and ornithine, through the action of regulatory elements common to arginase induction. We show here that it is subject to a second induction circuit, that which is responsible for urea amidolyase and urea permease induction by allophanate and defined by the regulatory mutants durL − and durM −
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  • 114
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    Current genetics 4 (1981), S. 85-90 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Nuclear isolation ; Percoll ; in vitro Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A procedure has been developed for the rapid isolation of yeast nuclei in high yield using Percoll gradients. The nuclei are substantially free of cytoplasmic contamination as measured by alcohol dehydrogenase activities, have the typical chromatin digestion pattern when digested with nucleases, are useful for isolation of nuclear proteins and for in vitro transcription experiments.
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  • 115
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; DEL1 ; rad ; ste7
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In DEL1 strains of the yeast, Saccharomyces cerevisiae, the iso-1-cytochrome c (CYC1) region is flanked on either side by Tyl elements in direct orientation which promote cyc1 deletions of the bracketed DNA in the haploid cell. In this study, we asked which genes might control this event by testing the possibility that the DEL1 mutation mechanism requires an enzyme (or enzymes) that is also utilized in the repair of damaged DNA. To this end, we independently coupled eight repair mutations, rad3–2, rad4–4, rad6–1, rad6–3, rad9–1, rev3–1, rad50–1, and rad51-1, toDEL1 and asked whether DEL1 was still functional. We found that none of these rad mutations significantly affects the mutation frequency of 10−6-10−5 established in DEL1 strains for the CYC1 locus. Furthermore, we determined that ste7, a temperature-sensitive sterile allele known to alter gene regulation in Ty-mediated mutations, is not required for DEL1 function. Finally, DEL1 is not temperature-sensitive at 23° or 37 °C.
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  • 116
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    Current genetics 7 (1983), S. 69-72 
    ISSN: 1432-0983
    Keywords: Yeast ; Protoplast ; Cybrid ; Plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Data presented here demonstrate that fusion of protoplasts of two different haploid strains of Saccharomyces cerevisiae having the same mating type leads to the formation of “fusants” and “cytoplasmic hybrids”. The nuclear and cytoplasmic genome of a “fusant” combine those of the parent haploid strains. The “cytoplasmic hybrid” possesses the haploid genome of one parent and the combined cytoplasmic genomes of both. In mouse cells lines such products have been termed “cybrids” and this term has therefore been adopted here (Bunn and Wallace 1974).
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  • 117
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    Current genetics 7 (1983), S. 93-100 
    ISSN: 1432-0983
    Keywords: Yeast ; RAD genes ; Cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Plasmids that complement the yeast mutations rad50-1, rad51-1, rad54-3 and rad55-3 were obtained by transforming strains that carried a leu2 marker and the particular rad mutation, with YEp13 plasmids containing near random yeast DNA inserts. Integration of these plasmids or of fragments of these plasmids was accomplished. Genetic studies using the integrants established the presence of the genes RAD51, RAD54 and RAD55 in the respective plasmids. However, a BamHI subclone of the rad50-1 complementing plasmid failed to integrate at the RAD50 locus, indicating that no homology exists between this fragment and the RAD50 gene. A BamHI fragment from the RAD54 plasmid was shown to be internal to the RAD54 gene: its integration within a wild type copy of RAD54 causes the cell to become Rad−; its excision is X-ray inducible and restores the Rad+ phenotype. Since cells bearing a disrupted copy of RAD54 are able to survive, we conclude that this gene is not essential.
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  • 118
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    Current genetics 7 (1983), S. 369-377 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Isoenzymes ; Induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tetrad analysis indicates that α-isopropylmalate synthase activity of yeast is determined by two separate genes, designated LEU4 and LEU5. LEU4 is identified as a structural gene. LEU5 either encodes another α-isopropylmalate synthase activity by itself or provides some function needed for the expression of a second structural gene. The properties of mutants affecting the biosynthesis of leucine and its regulation suggest that the expression of LEU1 and LEU2 (structural genes encoding isopropylmalate isomerase and β-isopropylmalate dehydrogenase, respectively) is controlled by a complex of a-isopropylmalate and a regulatory element (the LEU3 gene product). Similarities and differences between yeast and Neurospora crassa with respect to leucine biosynthesis are discussed.
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  • 119
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; TRP3 gene ; Deletion analysis ; Enzyme function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two sets of deletions, entering the TRP3 gene of Saccharomyces cerevisiae from the 3′- and the 5′-end were constructed. Complementation analysis with chromosomal trp3A, trp3B and trp3C mutations was done by introducing the 3′- and 5′-truncated gene on a multicopy 2 μm-vector. The N-terminal glutamine amido transferase function is encoded by a DNA fragment of 600–700 bp, and the C-terminal indole-3-glycerol-phosphate synthase function by a DNA fragment of about 900 bp, whereas both functions together are encoded by a contiguous DNA fragment of about 1,500 bp. The bi functional TRP3-peptide thus could be dissected into two catalytically independent peptides in vivo. For the indole-3-glycerol-phosphate synthase activity, independent catalytic activity was also demonstrated in vitro: deletions entering the TRP3 gene from the 5′-end, and lacking large parts of the sequence coding for the glutamine amidotransferase function, still are able to ex press a peptide exhibiting functional indole-3-glycerol phosphate synthase activity in vitro. Deletion plasmids pME505·De1C102·2μm and DelC10·2μm exhibited shorter TRP3 transcripts according to the deleted DNA-fragments (150 and 426 by respectively) but yielded peptides of invariable Mr of 35,000 d. Transcription and translation of these peptides, which probably represent the independently folding indole-3-glycerol-phosphate synthase core are discussed.
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  • 120
    ISSN: 1432-0983
    Keywords: Cephalosporium acremonium ; Mitochondrial DNA ; Autonomous replication sequence ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A fragment of DNA which functions as an autonomous replication sequence in yeast was cloned from Cephalosporium acremonium. Mitochondrial DNA (mtDNA) was isolated from an industrial strain of C. acremonium (08G-250-21) highly developed for the production of the antibiotic, cephalosporin C. Size, 27 kb, and restriction pattern indicated this DNA was identical to mtDNA previously isolated (Minuth et al. 1982) from an ancestral strain (ATTC 14553) which produces very low amounts of cephalosporin C. A 1.9 kb Pst1 fragment of the Cephalosporium mtDNA was inserted into a Pst1 site of the yeast integrative plasmid, Ylp5, to produce a 7.5 kb plasmid, designated pPS1. The structure of pPS1 was verified by restriction analysis and hybridization. PS1 transformed Saccharomyces cerevisiae (DBY-746) to uracil prototrophy at a frequency of 272 transformants/μg DNA. Transformation frequencies of 715 transformants/μg DNA and zero were obtained for the replicative plasmid, YRp7, and the integrative plasmid YIp5, respectively. Southern hybridization and transformation of E. coli by DNA from yeast transformed by pPS1 verified that pPS1 replicates autonomously in yeast. The uracil-independent pPS1-yeast transformants were mitotically unstable. The average retention of pPS1 after three days growth in selective and non-selective medium was 4.5% and 0.4%, respectively, compared to retentions of 4.6% and 0.5% for YRp7. The properties of pPS1 were compared to those of a related plasmid, pCP2. pCP2 was constructed (Tudzynski et al. 1982) by inserting the C. acremonium 1.9 kb Pst1 fragment into the yeast integrative plasmid, pDAM1.
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  • 121
    ISSN: 1432-0983
    Keywords: Yeast ; Mutant ; Uncoupler ; Resistance ; Permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary One mutant resistant to carbonylcyanide m-chlorophenylhydrazone (CCCP), an uncoupler of oxidative phosphorylation, was isolated in Saccharomyces cerevisiae. Genetic analysis showed that a single nuclear gene is responsible for increased resistance; this gene was dominant. The mutant showed cross-resistance or collateral sensitivity to several chemically-unrelated inhibitors (cycloheximide, dinitrophenol, tributhyltin chloride, chloramphenicol). The resistance of the mutant is related to a decreased uptake of CCCP which is not expressed in glucose-starved cells. It was shown that glucose induced a CCCP efflux which was more efficient in the mutant than in the wild-type cells. This effect was correlated to a greater acidification of the internal pH by glucose addition in the mutant cells. It was proposed that resistance was not due to a change of permeability of the plasmic membrane itself but to the change of internal pH which determines the extent of accumulation of weak acids or bases.
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  • 122
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    Current genetics 8 (1984), S. 567-573 
    ISSN: 1432-0983
    Keywords: Non-Mendelian ; Yeast ; Suppressor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Omnipotent suppressors cause translational ambiguity and have been associated with poor growth and inviability. We now report that a non-Mendelian element, [eta+], causes this inviability. In [eta−] strains the suppressors are not inviable. The [eta+] genetic element segregates to about 70% of the meiotic progeny, although almost all of the spores probably have the [eta+] phenotype for the first few divisions. Growth on 5 mM guanidine hydrochloride efficiently causes [eta+] strains to become [eta−]. The [eta+] factor has many similarities with the previously described [psi+] factor (Cox 1965, 1971). However, [eta+] and [psi+] differ in their patterns of inheritance, and by the fact that [psi+] affects ochre specific and not omnipotent suppressors, while the converse is true of [eta+].
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  • 123
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Yeast vectors ; Cosmids ; nif genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two vectors, termed pG63.11 (7.6 Kb) and pHCG3 (9.6 Kb), suitable for yeast transformation have been constructed. The pHCG3 vector has cosmid properties. Both vectors contain a single 3.3 Kb EcoRI-HindIII fragment of yeast origin which carries the yeast URA3 gene (1.1 Kb) and the origin of replication of the 2 µm plasmid (2.2 Kb). They confer ampicillin resistance and they contain 5 unique EcoRI,HpaI,HindIII,BamHI and SalI restriction sites. Cosmid pHCG3 was used to clone the nitrogen fixation (nif) gene cluster of Klebsiella pneumoniae carried by twoHindIII fragments of 17 and 26 Kb, respectively. The resulting cosmid, termed pGPC875 (53 Kb) which conferred a Nif+ phenotype to Escherichia coli, was introduced in yeast by transformation. No acetylene reduction activity was detectable in the transformants. However it was shown that the entire information for nitrogen fixation can be replicated and maintained intact in yeast for more than 50 generations of growth.
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  • 124
    ISSN: 1432-0983
    Keywords: Suppressors-tRNA ; Saccharomyces cerevisiae ; Nucleotide modification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have examined the tRNAs of two related strains of Saccharomyces cerevisiae, ψ + and ψ −, which differ with respect to an extrachromosomal genetic element that modulates the expression of genotypic and phenotypic suppression. Both the pattern of tRNAs synthesized and the level of nucleotide modification of several selected tRNA species were found to be the same in the ψ + and ψ − strains.
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  • 125
    ISSN: 1432-0983
    Keywords: Canavanine ; Yeast ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have found that the application of the amino acid analog canavanine to a culture of yeast cells transformed with chimeric plasmids based on the yeast 2-µm DNA plasmid increases the percentage of cells which have lost the transforming plasmid. This effect is found whether the plasmid carries the CAN1 sensitive allele and the yeast strain carries a can1 mutation confering resistance, or the plasmid contains no CAN1 allele and the yeast strain carries the wild-type CAN1 sensitive allele. Canavanine exerts this effect on yeast strains transformed with chimeric plasmids containing either a portion or the entire 2-µm DNA plasmid, yet canavanine does not appear to effect the maintenance of the native 2-µm DNA plasmid complement within the cell. The effect of canavanine on strains transformed with chimeric plasmids is the same whether or not the yeast strain also contains native 2-µm plasmid DNA. Neither the amino acid analog ethionine, the protein synthesis inhibitor cycloheximide, nor the DNA replication inhibitor hydroxyurea exhibit this effect. Some of the experimental results suggest that canavanine may be a curing agent rather than an agent which selects for spontaneous plasmid loss.
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  • 126
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    Current genetics 7 (1983), S. 393-397 
    ISSN: 1432-0983
    Keywords: Trehalose ; Glycogen ; Sporulation ; Germination ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutants with specific lesions were used to differentiate between the functions of glycogen and trehalose in S. cerevisiae. Diploids which harbor the glc1/glc1 mutation depend upon the phosphorylated, less active form of glycogen synthase and show a more active, phosphorylated form, of the enzyme trehalase. These conditions are due to a lesion in the regulating subunit of the cAMP-dependent protein kinase. Such cells are unable to sporulate. Diploids which contain the sst1/sst1 mutation have normal glycogen metabolism but their trehalose-6-phosphate synthase is not active. Such strains sporulate but germination is poor and only one-spore tetrads are formed. These results confirm that glycogen is needed to trigger sporulation while trehalose plays a role in the germination process. Different systems, I and II, of trehalose accumulation were proposed. System I would require the UDPG-linked trehalose synthase, whereas system II would constitute an alternative pathway, specifically induced or activated by the expression of a MAL gene. The presence of system II in its constitutive form in the constructed diploids would favour trehalose synthesis during growth on glucose, however, it did not overcome the glycogen deficiency during sporulation nor the lack of trehalose for germination. It seems that only system I, namely trehalose 6-P-synthase, plays a role in the germination process.
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  • 127
    ISSN: 1432-0983
    Keywords: Yeast ; Polyamines ; Termination ; In vitro Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of polyamines (spermidine and putrescine) on yeast suppressor tRNA-mediated readthrough of amber and UGA termination codons, in a homologous cell-free system, was examined. The efficiency of readthrough in a [psi+] lysate, mediated by exogenous suppressor tRNA, was significantly increased by polyamines as was the efficiency of endogenous UGA readthrough. The addition of polyamines, in the absence of exogenous suppressor tRNA, did not induce amber or ochre readthrough, nor could polyamines restore efficient termination readthrough in [psi−] lysates. It is concluded that polyamines interact with tRNA to increase the strength and specificity of the codon: anticodon interaction.
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  • 128
    ISSN: 1432-0983
    Keywords: Oversecretion mutants ; Protease defect ; Wall glucan defect ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two chromosomal mutations in yeast that result in oversecretion of the K1 killer toxin protein were examined. A recessive mutation in gene ski5 appears to lead to toxin oversecretion through a defect in a cell surface, PMSF-inhibited protease. A wild type killer strain degraded toxin following synthesis, and degradation could be partially prevented by addition of PMSF to the growth medium. The ski5 mutation caused an approximate ten fold oversecretion of toxin, similar to that seen in a PMSF-treated wild type culture, and no increased oversecretion in the presence of PMSF. The ski5 mutation caused oversecretion of other low molecular weight secreted proteins and appeared to oversecrete the α-factor pheromone, as judged by activity tests. The ski5 mutation was complemented by mutations in ski genes 1–4, and the mutant was not supersensitive to mating pheromones or K2 killer toxin. We also examined killer strains with a mutation in the nuclear gene krel which results in a defective (1→6)-β-D-glucan cell wall receptor for killer toxin. Such strains oversecrete toxin into the growth medium, but also, unexpectedly, oversecrete most other secreted proteins. The defect in (1→6)-β-D-glucan in these mutants appears to perturb the partitioning of secreted proteins between the cell wall and the medium.
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  • 129
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    Current genetics 8 (1984), S. 265-270 
    ISSN: 1432-0983
    Keywords: DHF Reductase ; Cloning ; Trimethoprim ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The dihydrofolate reductase gene of Saccharomyces cerevisiae has been isolated by selection of trimethoprim resistant Escherichia coli transformed with a gene bank of yeast DNA in plasmid pBR322. From 9.2 kilobase pair BamHI DNA fragment this gene has been localized to a 1.76 kb fragment, the restriction map of which appears different from those reported for the E. coli and the mouse dihydrofolate reductase genes. The enzyme encoded by the chimeric plasmid was established as yeast dihydrofolate reductase by its sensitivity to antifolates in vivo through growth studies and in vitro by enzyme assay. Since, the expression of this gene occurs independent of its orientation within the chimeric plasmid, the 1.76 kb fragment may contain functional regulatory sequences in addition to the structural sequences for yeast dihydrofolate reductase.
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  • 130
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; 5-aminolevulinate synthase ; Cloned gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have cloned the structural gene HEM1 for 5-aminolevulinate (ALA) synthase from Saccharomyces cerevisiae by transformation and complementation of a yeast hem1–5 mutant which was previously shown to lack ALA synthase activity (Urban-Grimal and Labbe Bois 1981) and had no immunodetectable ALA synthase protein when tested with yeast ALA synthase antiserum. The gene was selected from a recombinant cosmid pool which contained wild-type yeast genomic DNA fragments of an average size of 40 kb. The cloned gene was identified by the restauration.of growth on a non fermentable carbon source without addition of exogenous ALA. Sub cloning of partial Sau3A digests and functional analysis by transformation allowed us to isolate three independent plasmids, each carrying a 6 kb yeast DNA fragment inserted in either orientation into the single BamHI site of the vector pHCG3 and able to complement hem1–5 mutation. Analysis of the three plasmids by restriction endonucleases showed that HEM1 is contained within a 2.9 kb fragment. The three corresponding yeast trans formants present a 1, 2.5 and 16 fold increase in ALA synthase activity as compared to the wild-type strain. The gene product immunodetected in the transformant yeast cells has identical size as the wild-type yeast ALA synthase and its amount correlates well with the increase in ALA synthase activity.
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  • 131
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein gene ; Sequence analysis ; Northern blot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sequence analysis revealed that a gene coding for yeast ribosomal protein L34 comprises an amino acid coding region of 339 nucleotides which is interrupted by an intron after the 19th codon. Like for other yeast ribosomal protein genes analyzed thus far a strong codon bias was observed. The flanking and intervening sequences of this gene encoding L34 show several elements that are conserved in a number of split ribosomal protein genes in yeast. Northern blot analysis using an intron-specific probe demonstrated that the sequenced gene copy coding for L34 is transcribed in vivo.
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  • 132
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    Current genetics 9 (1984), S. 107-111 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; 2 μm minichromosomes ; Metrizamide gradients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two micrometer minichromosomes from Saccharomyces cerevisiae were isolated without detergent using metrizamide gradients. 2 μm minichromosomes showed a lower density in metrizamide gradients relative to genomic chromatin. Our results suggest a lower ratio of proteins to DNA in 2-μm minichromosomes as compared with genomic chromatin. The procedure described herein yields minichromosomes free of cellular chromatin and ribosomal protein contamination. This method may be useful for the isolation and characterization of other yeast minichromosomes.
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  • 133
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    Current genetics 7 (1983), S. 427-431 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; DNA ; Alkaline elution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The method of analysis of DNA in mammalian cells by alkaline elution from filters (Kohn et al. 1974) was adapted for studies on yeast DNA. By this technique spheroplasts obtained from yeast cells are lysed on filters and single-stranded DNA fragments selectively eluted by alkaline solutions. The procedure was applied to monitor the occurrence of replication intermediates and production of DNA single-strand breakage by MMS, and its repair in growth medium.
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  • 134
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    Current genetics 8 (1984), S. 81-84 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondrial genes ; Vegetative segregation ; Uniparental inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Zygotes of Saccharomyces cerevisiae that are heteroplasmic for mitochondrial alleles produce diploid progeny that are homoplasmic for one allele or the other, judged by the criterion that upon further subcloning they produce daughter cells of only one phenotype or the other. Here we show that when such cells are subjected to strong selection for the missing allele, it cannot be detected, so that it is probably not present in even a single copy.
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  • 135
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    Current genetics 4 (1981), S. 135-143 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondria ; Gene cloning ; Transfer RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have studied the organization and expression of a group of tRNA genes located on a 2,700 base pair portion of the yeast mitochondrial genome between the genetic markers cap (chloramphenicol resistance) and oxil (cytochrome oxidase subunit II). This region is spanned by mitochondrial DNA inserts of two recombinant plasmids, pYm162 and pYm267, which have been extensively mapped and sequenced. This tRNA group is composed of six tRNA genes, coding for tRNA AAR Lys , tRNA AGR Arg , tRNA GGN Gly , tRNA GAY Asp , tRNA AGY Ser , and tRNA CGN Arg . We report the sequence for the majority of the 2,700 base pair region including the genes for all six tRNAs. All six genes are oriented in the same direction and are, therefore, transcribed from the same DNA strand. Further, a comparison of the organization of this region with the analogous region of a related wild type strain shows that the tRNA gene order in the two strains is the same. Five of the six tRNA genes have corresponding transcripts in wild type RNA. Although a potential structural gene for tRNA CGN Arg is present, we do not detect a tRNA CGN Arg gene transcript.
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  • 136
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    Current genetics 7 (1983), S. 79-84 
    ISSN: 1432-0983
    Keywords: ars sequences ; Ustilago ; Yeast
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    Topics: Biology
    Notes: Summary U. maydis chromosomal DNA sequences which promote the autonomous replication of plasmid YIp5 in S. cerevisiae YNN27 have been isolated and three of them characterised in some detail. Their properties are idential to yeast ars sequences in that plasmids containing them are maintained extrachromosomally as circular double-stranded DNA molecules, are mitotically unstable in yeast transformants and transform yeast at high frequencies. There is no sequence homology between the three U. maydis sequences and they are not reiterated in the U. maydis genome.
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  • 137
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    Current genetics 7 (1983), S. 433-438 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Yeast transformation ; Yeast autonomously replicating sequences ; Ribosomal RNA genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously demonstrated that the loss of Rcp-CEN3, a centromeric plasmid containing yeast rDNA autonomously replicating sequences (ARS) is as high as around 50% per generation for most yeast strains. In this study we have attempted to elucidate mechanisms underlying the high mitotic instability of Rcp-CEN3. For this purpose a tandem duplication of a rDNA ARS was constructed in Rcp-CEN3. The new plasmid having two ARSs possesses a markedly higher mitotic stability as compared to a monoARS Rcp-CEN3. The mitotic stability of this centromere-containing plasmid which has two replicators corresponds to the calculated value for the mitotic stability of two monoARS plasmids Rcp-CEN3 in given cells. Genetic analysis has demonstrated that both plasmids having one or two ARSs are maintained in the single copy state. These results demonstrate that the mitotic instability of centromeric plasmid Rcp-CEN3 carrying a rDNA ARS is associated with the absence of stringent control of replication from the rDNA ARS. A possible mechanism of replication of the chromosomal rDNA repeats in yeast is discussed in the light of this data.
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  • 138
    ISSN: 1432-0983
    Keywords: Yeast ; Recombination ; Conversion ; Restoration
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    Notes: Summary Heteroduplex repair models of recombination predict that restoration of the parental genotype from heteroduplex will have the same frequency as conversion to the genotype of the homologue. We have reported previously (Savage and Hastings 1981) that the proportion of intragenic reciprocal events in the his1 locus of yeast is too low for this expectation. In this study, two classes of recombination event involving longer lengths of his1 are compared in a series of crosses using a constant right-hand marker. This comparison gives a value for conversion: restoration for the left-hand markers which is independant of the method used before. The values obtained by the two methods are significantly correlated, confirming that there is a disparity in the ratio of conversion to restoration, and that this disparity is seen as a deficiency of restoration for five alleles of his1.
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  • 139
    ISSN: 1432-0983
    Keywords: Iso-1-cytochrome c ; Saccharomyces cerevisiae ; Heme ; Transcription
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    Notes: Summary A Saccharomyces cerevisiae mutant (hem1 cycl-1) was transformed with plasmids bearing a chromosomal centromer (CEN3) and a 2 μm DNA replication origin. In one of the plasmids a functional CYC1 gene was present, in a second plasmid an XhoI fragment located between bases -245 and -678 upstream from the translation initiation codon had been deleted, in a third plasmid this region had been inverted. Results of hybridization experiments carried out with mRNA isolated from heme-deficient and heme-containing transformants indicated that heme controls transcription of the CYC1 gene and that DNA sequences located within the upstream XhoI fragment are involved in activation of the gene by heme.
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  • 140
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; TRP3 gene ; Sequence analysis ; Enzyme function
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    Topics: Biology
    Notes: Summary The structure and function of the TRP3 gene of Saccharomyces cerevisiae were analyzed. Subcloning of an original 4.8 kb BamHI DNA fragment, carrying the yeast TRP3 gene, allowed for a localization of the gene on a 2.5 kb ClaI/BamHI fragment. Transcription was found to proceed from the ClaI site towards the BamHI site. Three major transcription start sites were determined at positions −92, −87, and −81 by S1-mapping. The synthesis of the TRP3 gene is regulated by the general control, and was found to take place- at the transcriptional level. The sequence of the 5′-noncoding region up to position −400 and part of the coding region to position 840 were determined. The 5′-noncoding region contains sequences common to most amino acid biosynthetic genes known so far, namely a presumptive ribosome binding site, “Goldberg-Hogness boxes”, and a consensus sequence, possibly involved in the general control. For the coding region a single open reading frame was found. The deduced amino acid sequence was aligned with homologous amino acid sequences of Neurospora crassa, Pseudomonas putida and Escherichia coli. The exceptionally high homology (40–60%) between these sequences led us to postulate that the TRP3 gene product is of the structure NH2-glutamine amidotransferase-indole-3-glycerol-phosphate synthase-COOH.
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  • 141
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    Current genetics 8 (1984), S. 429-437 
    ISSN: 1432-0983
    Keywords: Yeast ; Heat-shock response ; Mitochondrial inhibition ; 2D electrophoresis
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    Topics: Biology
    Notes: Summary Conventional and two dimensional (2D) electrophoresis on ultrathin horizontal slab gels shows that heat shock proteins are synthesized and heat stroke proteins are curtailed after the transfer of Saccharomyces cerevisiae strain Z270 from 23 °C to 37 °C. Upon addition of the mitochondrial translation inhibitor erythromycin to cell cultures which incorporated labelled methionine at 23 °C, and after the transfer to 37 °C, we have shown that: a) in extracts of cells labelled at 23 °C, translational products sensitive to erythromycin could be observed on 2D gels; the synthesis of some of these proteins was enhanced, whereas the synthesis of some others declined when the labelling was carried out 20 min after the transfer to 37 °C; b) there are heat shock proteins whose induction at 37 °C was prevented by erythromycin; c) labelling of a number of proteins became weaker at 37 °C, but not at 23 °C, when this was done in the presence of erythromycin; d) two proteins were detectable only in samples labelled at 37 °C in the presence of erythromycin.
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  • 142
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Cloning ; Suppressor
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    Notes: Summary A plasmid, pYsup1-1, containing a DNA fragment able to suppress the recessive mutant phenotype of the suppressor locus sup1 (allele sup1-ts36) of Saccharomyces cerevisiae was isolated from a bank of yeast chromosomal DNA cloned in cosmid p3030. The complementing gene was localized on a 2.6 kb DNA fragment by further subcloning. Evidence is presented that the cloned DNA segment codes for the sup1 structural gene (chromosome IIR).
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  • 143
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    Current genetics 8 (1984), S. 575-580 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Candida utilis ; Protoplast fusion
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    Notes: Summary Auxotrophic mutants of Saccharomyces cerevisiae and Candida utilis were hybridized through protoplast fusion. Spontaneous, UV- and FPA-induced mitotic segregation indicated that after cell fusion, exclusion of the S. cerevisiae nucleus or nuclear fusion followed by preferential loss of S. cerevisiae chromosomes can take place. Some of the hybrids were stable. One of them, expressed mating and sporulation functions of the S. cerevisiae parent. Thus, markers from both parents could be recovered as mitotic and meiotic segregants.
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  • 144
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    Keywords: Yeast ; Mitochondrial ochre mutations ; Specificity of suppressors ; Mitoribosomal misreading ; Intron-encoded maturases
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    Notes: Summary We describe studies on the action spectra of the mitochondrial suppressor mim3-1 and the three alleles of nuclear suppressor nam3. Their specificity of action was tested on 516 mit − mutations located in different mitochondrial genes. The degree of suppression was quantified by the extent of cytochrome oxidase and cytochrome b synthesis. We show that the four suppressors are allele-specific gene-nonspecific informational suppressors. They would act by changing the structure of the small mitoribosomal subunit which would decrease fidelity of translation enabling misreading of some but not all ochre codons. The implications of the results on the role of intron encoded maturases are discussed.
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  • 145
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial ochre mutations ; Nuclear informational suppressors ; Mitochondrial informational suppressors
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    Notes: Summary A systematic search for suppressors of mutations which cause a deficiency in the splicing of mitochondrial RNA has been undertaken. These splicing mutations were localized in the mRNA-maturase coding sequence of the second intron of the cob-boxgene, i.e. in the box3locus. A total of 953 revertants (mostly spontaneous in origin) were isolated and their genetic nature (nuclear vs. mitochondrial) and phenotype characterized. Most revertants were mitochondrially determined and displayed a wild-type phenotype. A mitochondrial suppressor unlinked with the box3 −target mutation was uncovered among the revertants displaying a pseudo-wild phenotype: out of 26 revertants analyzed, derived from 7 different box3− mutants only one such suppressor mutation mim3-1 was found. It was localized by rho− deletion mapping in the region between the oxi2 and oxi3 gene, within (or in the vicinity) the gene specifying the 15S ribosomal RNA. Nuclear suppressors were isolated from seven different box3 −mutants. All were recessive and had a pseudo-wild phenotype. Three such suppressors nam3-1, nam3-2 and nam3-3 were investigated more extensively. Tetrad analysis has shown that they are alleles of the same nuclear locus NAM3 and mitotic analysis has shown that they do not segregate mitotically.
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  • 146
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    Archives of microbiology 128 (1981), S. 384-389 
    ISSN: 1432-072X
    Keywords: Didymium iridis ; Microcyst ; Excystment ; Germination ; Ultrastructure ; Mycetozoa ; Myxomycetes ; Myxamoeba
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    Notes: Abstract Microcysts of the myxomycete Didymium iridis were induced to excyst by transfer to 5mM potassium phosphate buffer. After 1 h in suspension, 90% of the microcysts had germinated into myxamoebae distinguishable by phase contrast microscopy and staining with Lugol's iodine. Both pH and osmolarity affected the kinetics of excystment. The rate and extent of excystment were decreased by cycloheximide but remained unaffected by actinomycin D, suggesting a requirement for protein synthesis but not RNA synthesis. Initially, the outer wall layers separated from the inner layer, which gradually expanded and loosened. The protoplast rehydrated and reverted to a vegetative morphology. Excysting cells were characterized by nucleolar inclusions, changes in the nuclear envelope and plasma membrane, appearance of ringed cisternal elements and microbodies in the cytoplasm, and formation of a densely fibrous zone adjacent to the site of emergence. Excysting populations have been classified into characteristic stages: mature, initiated, swollen, and pre-emergent microcysts.
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  • 147
    ISSN: 1432-072X
    Keywords: Pyrophosphate ; Polymerie acid-soluble poly-phosphates ; Budding process ; Yeast
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    Notes: Abstract In the cells of hybrid yeast strain Saccharomyces N.C.Y.C. 644 SU3 (Karlsberg collection), a large amount of pyrophosphate (30–300 μmol/g of dry weight) accumulates whatever the aeration conditions and the content of glucose in the medium. The content of pyrophosphate is 10–1000 times higher than that of ATP. At the early and mid-exponential growth phases two maxima of pyrophosphate accumulation are observable. The periods of maximal pyrophosphate accumulation in yeast coincide with those of the minimal content of polymeric acid-soluble polyphosphates and intense budding. In the light of the data obtained, the question is discussed as to the relationship between the metabolism of pyrophosphates and acid-soluble polyphosphates in yeast.
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  • 148
    ISSN: 1432-072X
    Keywords: Germination ; Glycogen ; Outgrowth ; Schizosaccharomyces pombe ; Spore ; Trehatase ; Trehalose ; Yeast
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    Notes: Abstract Quantitative changes in various carbohydrates of Schizosaccharomyces, pombe spores during germination and outgrowth were studied. Trehalose decreased rapidly, shortly after onset of germination, while glycogen remained constant throughout germination and outgrowth. Alkali-insoluble carbohydrates decreased after the lag period of about 40 min. The content of alkali-soluble carbohydrates was constant during germination, but increased remarkably in parallel with germtube formation. The mechanism of rapid degradation of trehalose during germination was also studied. The activity of trehalase (EC 3.2.1.28) was detected only in the cell wall fraction of isolated spores. Trehalase activity in the cell wall fraction was not enhanced during germination. Trehalose was not found in the isolated spore walls, but in the soluble fraction. These facts strongly suggested that trehalose, and trehalase were spatially separated in dormant spores and that trehalase became accessible to trehalose upon germination.
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  • 149
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    Archives of microbiology 129 (1981), S. 47-48 
    ISSN: 1432-072X
    Keywords: Adenylate energy charge ; Phosphate ; Saccharomyces ; Sporulation ; Yeast
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    Notes: Abstract The induction of sporulation in yeast is generally accompanied by a sharp increase in energy metabolism which is evidenced by a rise of the adenylate energy charge by that time. The energy charge can be held at a low level by limitation of the phosphate supply in the growth medium. Ascus formation remains unaffected by this treatment. This suggests that the rise in ATP production normally encountered during early sporulation is not essential for the initiation of sporulation.
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  • 150
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    Keywords: Saccharomyces cerevisiae ; Borrelidin ; Aspartokinase ; Feedback regulation ; Threonine pool ; Homoserine pool ; S-Adenosylmethionine
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    Notes: Abstract Borrelidin is a specific inhibitor of the threonyl-tRNA-synthethase. A class of dominant borrelidin resistant mutants (BOR1) of Saccharomyces cerevisiae was biochemically characterized. The mutants possess an altered aspartokinase which is insensitive to threonine inhibition. The threonine and homoserine pools in these mutants are 22 times larger than in the wild type. By feeding aspartate under a variety of conditions the homoserine pool is increased even 57 times whilst the threonine pool is reduced.
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  • 151
    ISSN: 1432-072X
    Keywords: Agglutination substance ; α Pheromone ; Cell cycle ; Ethyl N-phenylcarbamate ; Mating reaction ; Microtubules ; Saccharomyces cerevisiae
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    Notes: Abstract Effects of ethyl N-phenylcarbamate (EPC) on the mating reaction of Saccharomyces cerevisiae were studied, with special attention on the effect on the α pheromone action. EPC inhibited zygote formation at a concentration which promoted induction of sexual agglutinability. EPC enhanced agglutinability induction by α pheromone, but inhibited α-pheromone-induced formation of large pearshaped cells in a mating type. The enhancement of agglutinability induction was accompanied with increased production of a agglutination substance and inhibition of α pheromone inactivation. EPC arrested the cell cycle of a cells probably in the step controlled by CDC19, CDC35, cAMP etc., just before the step controlled by CDC28, α pheromone etc.
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  • 152
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Glucan synthetase ; EDTA ; Magnesium ; Sucrose ; Fluoride
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    Notes: Abstract Yeast β(1–3) glucan synthetase is stimulated and stabilized by EDTA. Sucrose protects the enzyme from selfinactivaton. Preincubation of cell free extracts at low sucrose concentrations indicates a slow transition of the enzyme towards dissociation. Transition kinetics at 30° C and 0° C in the presence and in the absence of sucrose are interpreted assuming that a subunit is thermolabile in the free state and that sucrose increases its stability. Magnesium is deletereous for glucan synthetase in cell-free extracts. Chaotropic agents inactivate glucan synthetase according to their capacity to solubilize and depolymerize biological compounds. Fluoride plays a special role in the activation of glucan synthetase. Its action appears to be dependent on the presence of GTP (or other nucleotides). The role of all these agents on the activity and stability of the enzyme is interpreted in a unified scheme.
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  • 153
    ISSN: 1432-072X
    Keywords: Yeast ; Phosphate uptake ; Phosphate-binding protein ; Anti-phosphate-binding protein antibodies
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    Notes: Abstract The purification of a phosphate-binding protein (PiBP2) by immunoadsorption is described. The entire anti phosphate-binding protein 2 antibodies as well as the Fab fragments obtained from these antibodies inhibit Pi uptake by whole cells. The inhibition is a mixed type of inhibition (V m and K m are affected). These results should be regarded as a possible involvement of phosphate-binding protein 2 in Pi uptake. The binding of 125I-labelled fragments prepared from anti phosphate-binding protein 2 antibodies to whole cells, to shocked cells and to protoplasts has been investigated. The results confirm the release of phosphate-binding protein by osmotic shock and during protoplast formation. From these findings, a cell-wall localisation, near the cell surface of the phosphate-binding protein should be proposed.
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  • 154
    ISSN: 1432-072X
    Keywords: Methanogenium tatii ; Ultrastructure ; Physiology ; Glycoproteins ; DNA-DNA Homology ; Taxonomy ; Archaebacteria
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    Notes: Abstract A new coccoid methanogen, Methanogenium tatii, was isolated and characterized. The mesophilic isolate can grow on and produce methane from H2:CO2 and formate. For growth acetate is strictly required. The cell shape, the G+C content of 54 mol% and DNA-DNA homology data suggest it to be a Methanogenium species.
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  • 155
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    Archives of microbiology 137 (1984), S. 357-361 
    ISSN: 1432-072X
    Keywords: Yeast ; Saccharomyces cerevisiae ; Killer toxin ; Extracellular glycoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A total of 13 killer toxin producing strains belonging to the genera Saccharomyces, Candida and Pichia were tested against each other and against a sensitive yeast strain. Based on the activity of the toxins 4 different toxins of Saccharomyces cerevisiae, 2 different toxins of Pichia and one toxin of Candida were recognized. The culture filtrate of Pichia and Candida showed a much smaller activity than the strains of Saccharomyces. Extracellular killer toxins of 3 types of Saccharomyces were concentrated and partially purified. The pH optimum and the isoelectric point were determined. The killer toxins of S. cerevisiae strain NCYC 738, strain 399 and strain 28 were glycoproteins and had a molecular weight of Mr=16,000. The amino acid composition of the toxin type K2 of S. cerevisiae strain 399 was determined and compared with the composition of two other toxins.
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    Archives of microbiology 138 (1984), S. 183-186 
    ISSN: 1432-072X
    Keywords: Yeast ; Nitrogen assimilation ; Nitrate reductase ; Nitrite reductase ; Candida utilis ; Food yeast ; Nitrate reduction ; Nitrogenous oxide
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    Topics: Biology
    Notes: Abstract Assimilation of nitrate and various other inorganic nitrogen compounds by different yeasts was investigated. Nitrate, nitrite, hydroxylamine, hydrazine, ammonium sulphate, urea and L-asparagine were tested as sole sources of nitrogen for the growth of Candida albicans, C. pelliculosa, Debaryomyces hansenii, Saccharomyces cerevisiae, C. tropicalis, and C. utilis. Ammonium sulphate and L-asparagine supported the growth of all the yeasts tested except D. hansenii while hydroxylamine and hydrazine failed to support the growth of any. Nitrate and nitrite were assimilated only by C. utilis. Nitrate utilization by C. utilis was also accompanied by the enzymatic activities of NAD(P)H: nitrate oxidoreductase (EC 1.6.6.2) and NAD(P)H: nitrite oxidoreductase (EC 1.6.6.4), but not reduced methyl viologen-or FAD-nitrate oxidoreductases (EC 1.7.99.4). It is demonstrated here that nitrate and nitrite reductase activities are responsible for the ability of C. utilis to assimilate primary nitrogen.
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  • 157
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    Archives of microbiology 138 (1984), S. 229-232 
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces torulosus ; Morphology ; Ultrastructure ; Verrucate spores ; Knobby ornamentation ; Sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The type strain of Streptomyces torulosus Lyons and Pridham (1971) was studied by scanning- and transmission electron microscope. Spore chains were formed in spirals by aerial mycelium. The spores were connected by nozzles in which small channels could be observed. The knobby ornamentations of the spores arised on a thin fibrous sheath, enveloping the spore chains. These irregular blunt projections, called knobs, had varying diameters of 100 to 250 nm. The base of the knob, consisting of globose to flattened electron dense material, was sitting directly on the sheath. It was covered by several small vesicles of the same material. Each hollow vesicle beared a thin bowlshaped shell of electron transparent material. In general, the cupular bowls and their supporting vesicles became easily depressed on their base, but not detached from the surface of the spores. This type of knobby spore ornamentation was suggested to be designated as a verrucate spore type.
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  • 158
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    Archives of microbiology 130 (1981), S. 204-212 
    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
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    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
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  • 159
    ISSN: 1432-072X
    Keywords: Candida boidinii ; Yeast ; Peroxisomes ; β-Oxidation ; d-Amino acid oxidase
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    Topics: Biology
    Notes: Abstract We have studied the induction of peroxisomes in the methylotrophic yeast Candida boidinii by d-alanine and oleic acid. The organism was able to utilize each of these compounds as the sole carbon source and grew with growth rates of μ=0.20 h-1 (on d-alanine) or μ=0.43 h-1 (on oleic acid). Growth was associated with the development of many peroxisomes in the cells. On d-alanine a cluster of tightly interwoven organelles was observed which made up 6.3% of the cytoplasmic volume and were characterized by the presence of d-amino acid oxidase and catalase. On oleic acid rounded to elongated peroxisomes were dominant which were scattered throughout the cytoplasm. These organelles contained increased levels of β-oxidation enzymes; their relative volume fraction amounted 12.8% of the cytoplasmic volume.
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  • 160
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    Archives of microbiology 154 (1990), S. 267-273 
    ISSN: 1432-072X
    Keywords: Yeast ; Saccharomyces cerevisiae ; (R)-2,3-Butanediol dehydrogenase ; Stereospecificity ; Gas chromatographic analysis of enantiomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A NAD-dependent (R)-2,3-butanediol dehydrogenase (EC 1.1.1.4), selectively catalyzing the oxidation at the (R)-center of 2,3-butanediol irrespective of the absolute configuration of the other carbinol center, was isolated from cell extracts of the yeast Saccharomyces cerevisiae. Purification was achieved by means of streptomycin sulfate treatment, Sephadex G-25 filtration, DEAE-Sepharose CL-6B chromatography, affinity chromatography on Matrex Gel Blue A and Superose 6 prep grade chromatography leading to a 70-fold enrichment of the specific activity with 44% yield. Analysis of chiral products was carried out by gas chromatographic methods via pre-chromatographic derivatization and resolution of corresponding diasteromeric derivatives. The enzyme was capable to reduce irreversibly diacetyl (2,3-butanediol) to (R)-acetoin (3-hydroxy-2-butanone) and in a subsequent reaction reversibly to (R,R)-2,3-butanediol using NADH as coenzyme. 1-Hydroxy-2-ketones and C5-acyloins were also accepted as substrates, whereas the enzyme was inactive towards the reduction of acetone and dihydroxyacetone. The relative molecular mass (M r) of the enzyme was estimated as 140 000 by means of gel filtration. On SDS-polyacrylamide gel the protein decomposed into 4 (identical) subunits of M r 35 000. Optimum pH was 6.7 for the reduction of acetoin to 2,3-butanediol and 7.2 for the reverse reaction.
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  • 161
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    Keywords: Peroxisome ; Methanol ; Methylamine ; Yeast ; Hansenula polymorpha ; Alcohol oxidase ; Amino oxidase ; Catalase ; Catabolite inactivation ; Turnover ; Cytochemical localization
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    Topics: Biology
    Notes: Abstract Growth of Hansenula polymorpha in shake flasks and chemostat cultures in the presence of methanol as the sole source of carbon and methylamine as the sole source of nitrogen was associated with the development of peroxisomes in the cells. The organelles were involved in the concurrent oxidation of these two compounds, since they contained both alcohol oxidase and amine oxidase, which are key enzymes in methanol and methylamine metabolism, respectively. In addition catalase was present. Peroxisomes with a completely crystalline substructure were observed in methanol-limited chemostat-grown cells. Amine oxidase probably formed an integral part of these crystalloids, whereas catalase was present in a freely diffusable form. Transfer of cells, grown in a methanol-limited chemostat in the presence of methylamine into glucose/ammonium sulphate media resulted in the loss of both alcohol oxidase and amine oxidase activity from the cells. This process was associated with degradation of the crystalline peroxisomes. However, when cells were transferred into glucose/methylamine media, amine oxidase activity only declined during 2 h after the transfer and thereafter increased again. This subsequent rise in amine oxidase activity was associated with the development of new peroxisomes in the cells in which degradation of the crystalline peroxisomes, originally present, continued. These newly formed organelles probably originated from peroxisomes which had not been affected by degradation. When in the methanollimited chemostat methylamine was replaced by ammonium sulphate, repression of the synthesis of amine oxidase was observed. However, inactivation of this enzyme or degradation of peroxisomes was not detected. The decrease of amine oxidase activity in the culture was accounted for by dilution of enzyme as a result of growth and washout.
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  • 162
    ISSN: 1432-072X
    Keywords: Arthrobacter ; Facultative methylotroph ; Amine oxidase ; Catalase ; RuMP cycle of formaldehyde fixation ; Ultrastructure
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    Topics: Biology
    Notes: Abstract A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3.) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine-and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formal-dehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
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  • 163
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    Archives of microbiology 129 (1981), S. 146-149 
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Inhibition of tryptophanyl-tRNA synthetase ; Mode of action of tryptophan analogues ; Tryptophan analogue degradation
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    Topics: Biology
    Notes: Abstract The effect of the tryptophan analogue 4-methyltryptophan in Saccharomyces cerevisiae has been investigated. 4-Methyltryptophan inhibits the aminoacylation of tryptophan specific transfer ribonucleic acid (tRNATrp). The mode of inhibition is competitive and the analogue is not charged onto tRNATrp. Thus 4-methyltryptophan application depletes the cells from charged tRNATrp. As a consequence cell growth and protein synthesis are strongly reduced. 4-Methyltryptophan is degraded efficiently in culture media inoculated with the wild type strain; the effects of 4-methyltryptophan were therefore found to be transient.
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  • 164
    ISSN: 1432-072X
    Keywords: Fructose-1,6-bisphosphatase ; Phosphofructokinase ; Antagonistic enzymes ; Glycolytic intermediates ; ATP ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract The intracellular levels of adenosine triphosphate and several glycolytic intermediates were determined in Saccharomyces cerevisiae in relation to the presence of the metabolically antagonistic enzymes phosphofructokinase and fructose-1,6-bisphosphatase. Phosphofructokinase is synthesized constitutively in cells grown in the presence of glucose and fructose-1,6-bisphosphatase derepression occurs upon the exhaustion of glucose from the growth medium. Transcriptional regulation of fructose-1,6-bisphosphatase was suggested based on experiments with wild type cells using 8-hydroxyquinoline, a known inhibitor of nuclear transcription, and with the S. cerevisiae mutant strain A364A (ts-136) blocked in the transport of nuclear RNA at non-permissive temperature. The level of phosphofructokinase was reduced more than 25-fold under conditions of high citrate accumulation in an aconitaseless, glutamate requiring mutant strain, MO-1-9B. There was a rapid decrease in the levels of adenosine triphosphate and fructose-1,6-bisphosphate at the end of log-phase of culture growth when both fructose-1,6-bisphosphatase and phosphofructokinase were present in the cells simultaneously. The changes in the levels of key glycolytic intermediates, but not the changes in adenosine triphosphate, during the simultaneous presence of these two enzymes, can be explained without involving any futile cycling.
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  • 165
    ISSN: 1432-072X
    Keywords: Hansenula wingei ; Induction ; Saccharomyces cerevisiae ; Saccharomyces kluyveri ; Sex pheromone ; Sexual agglutinability ; Sexual agglutination
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    Topics: Biology
    Notes: Abstract The yeast, Hansenula wingei has two mating types designated 5 and 21. Cells of each mating type were found to produce mating type-specific sex pheromone which induces sexual agglutinability of the opposite mating type. Crude fractions of these pheromones were prepared by using an Amberlite CG 50 (H+ type) column. The agglutinability-inducing action of the pheromones required glucose as carbon source, but no external nitrogen source. The action of the pheromones was inhibited by 5 μg/ml cycloheximide. The optimum pH for the pheromone action was 4.0. α Pheromones of Saccharomyces cerevisiae and Saccharomyces kluyveri induced sexual agglutinability of 5 mating type cells but did not that of 21 mating type cells. a Pheromones of the Saccharomyces yeasts had no effect on both 5 and 21 mating type cells. The sex pheromones of H. wingei had no effect on the sexual agglutinability of inducible a cells of S. cerevisiae. From the experimental results obtained so far, we propose to call 5 and 21 mating types in H. wingei a and α mating types, respectively.
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  • 166
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    Archives of microbiology 137 (1984), S. 104-108 
    ISSN: 1432-072X
    Keywords: Chloroquine ; Yeast ; Proteolysis ; ATP hydrolysis ; Glucose consumption ; Ethanol formation
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    Topics: Biology
    Notes: Abstract In yeast cells, degradation of cellular proteins was inhibited by addition of chloroquine to the medium as shown by a decrease of the release of trichloroacetic acid-soluble radioactivity from prelabelled cell protein. Penetration of chloroquine into the cells was strongly enhanced with increasing pH value of the medium. The concentration in the cells reached 5–14 times that in the medium of pH 8.0. Fluorescence microscopy showed that chloroquine was concentrated in the vacuoles of the cells. Chloroquine, at concentrations attained in the cells, inhibited the activities of vacuolar proteinases in vitro. Furthermore, chloroquine caused a rapid and drastic decrease of the ATP content of the cells and prevented the fermentation of glucose and formation of ethanol under aerobic conditions.
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  • 167
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Bud scar ; Scar ring ; Glucan ; Chitin ; Mannan ; Cytology ; Electron and X-ray diffractions ; Physico-chemical characterization
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Scar rings (SR) from scarless cells at the early stages of budding and mature bud scars from Saccharomyces cerevisiae isolated by both chemical and enzymic treatment of cell walls were observed by selected-area electron diffraction (SAED), X-ray diffraction and electron microscopy with simultaneous physico-chemical characterization (including molar mass, intrinsic viscosity and crystallite size) of α-chitin and glucan. The SR, composed of glucan with strong 0.608; 0.397 and 0.293 nm X-ray reflections, was formed at the start of budding. The SAED patterns of α-chitin both in the adjacent circular zone and in the parts of newly formed primary septum (PS), observed when the development of the PS started, did not differ from those of α-chitin in the single mature bud scar. The bud scar consisted of α-chitin, glucan and mannan and their content, as well as the crystallite size of chitin, depended on the mode of preparation.
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  • 168
    ISSN: 1432-072X
    Keywords: Agglutination substance ; Cell-cell recognition ; Glycoprotein ; Mating ; Saccharomyces cerevisiae ; Sexual agglutinability ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An a-mating-type-specific substance responsible for sexual agglutination was purified to 397-times in specific activity (units/mg protein) from the cytoplasm of a-mating type cells. The purified substance gave a single band stained with PAS reagent but not with both Coomassie brilliant blue and silver staining reagent by polyacrylamide gel electrophoresis in the presence of 8 M urea. However, incorporation of [35S]methionine and Lowry reaction clearly indicate that the substance is a glycoprotein. The substance specifically masked sexual agglutinability of cells of the opposite mating type α, indicating univalent action. The substance is a glycoprotein with a carbohydrate content of 90%, a pI of 4.5, and a molecular weight of 130,000. The substance was inactivated by 2-mercaptoethanol and proteolytic enzymes but not by glycolytic enzymes. The substance formed a complementary complex having no biological activity when mixed with α-agglutination substance from the wall or cytoplasm of α-cells in vitro.
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  • 169
    ISSN: 1432-072X
    Keywords: α Pheromone ; Cell cycle ; G1 arrest ; Hansenula wingei ; Saccharomyces cerevisiae ; Shmoo
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    Notes: Abstract The cell cycle of a (5) mating type cells of Hansenula wingei was arrested in the G1 phase by α pheromone of Saccharomyces cerevisiae but not by α(21) pheromone of H. wingei, although both the α pheromones are known to induce sexual agglutination ability of a mating type cells of H. wingei. Cells of α mating type of H. wingei became shmooed or arrested in the G1 phase in response to neither a pheromone of H. wingei nor α pheromone of S. cerevisiae.
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  • 170
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    Archives of microbiology 154 (1990), S. 175-178 
    ISSN: 1432-072X
    Keywords: Killer toxin ; Hanseniaspora uvarum ; Yeast
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    Topics: Biology
    Notes: Abstract The yeast Hanseniaspora uvarum liberates a killer toxin lethal to sensitive strains of the species Saccharomyces cerevisiae. Secretion of this killer toxin was inhibited by tunicamycin, an inhibitor of N-glycosylation, although the mature killer protein did not show any detectable carbohydrate structures. Culture supernatants of the killer strain were concentrated by ultrafiltration and the extracellular killer toxin was precipitated with ethanol and purified by ion exchange chromatography. SDS-PAGE of the electrophoretically homogenous killer protein indicated an apparent molecular mass of 18,000. Additional investigations of the primary toxin binding sites within the cell wall of sensitive yeast strains showed that the killer toxin of Hanseniaspora uvarum is bound by β-1, 6-d-glucans.
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  • 171
    ISSN: 1432-072X
    Keywords: 13C NMR spectroscopy ; Yeast ; Debaryomyces hansenii ; Osmoregulation ; Compatible solute ; Salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract High resolution 13C NMR combined with chemical analysis were used to study the formation of metabolites from [1-13C]-labelled glucose by the salt-tolerant yeast Debaryomyces hansenii after transfer to media containing 8% NaCl. Time course spectroscopy of an aerobic cell suspension showed [1,3-13C]glycerol as the predominant end product. Perchloric acid extracts revealed additional less prominent incorporation of label into arabinitol, trehalose, glutamic acid, and alanine. The incorporation into trehalose and arabinitol showed a transient increase after shift to the high salinity medium. It is concluded that glycerol and arabinitol are the major organic solutes in D. hansenii, the production of glycerol being strongly induced by high salinity. Analysis of labelled extracts of D. hansenii after transfer to 8% NaCl media containing [1-13C]- or [6-13C]glucose, demonstrated that glucose is dissimilated via a combination of the Embden-Meyerhof-Parnas pathway and the pentose phosphate pathway, with the former playing a major role in glycerol formation and the latter in arabinitol production. The almost exclusive labelling of C5 of arabinitol from [6-13C]glucose indicates that the pathway to arabinitol proceeds via reduction of ribulose-5-phosphate.
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  • 172
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    Archives of microbiology 134 (1983), S. 64-67 
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Anaerobic growth ; Hungate technique ; Tween 80 ; Ergosterol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Saccharomyces cerevisiae, Nontrachet strain 522 was successfully grown anaerobically on various glucose concentrations in Yeast Nitrogen Base (YNB) medium (pH 3.5) prepared under an atmosphere of carbon dioxide (CO2). This growth occurred in the absence of Tween 80 and ergosterol. The medium, prepared using the Hungate technique for cultivation of strictly anaerobic bacteria, contained the reducing agent cysteine·HCl·H2O (0.03%). Anaerobic growth was stimulated by the addition of Tween 80 and ergosterol to the anaerobic medium.
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  • 173
    ISSN: 1432-072X
    Keywords: Carbon catabolite inactivation ; Yeast ; Malate dehydrogenase ; Fructose-1,6-bisphosphatase ; Glycolytic block mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experimental conditions have been elaborated to test for reversibility of the malate dehydrogenase inactivation (E.C.1.1.1.37) after addition of glucose to derepressed yeast cells. Malate dehydrogenase inactivation was shown to be irreversible at all stages of inactivation. In contrast fructose-1,6-bisphosphatase inactivation (E.C.3.1.11) remained reversible for at least 30 min after addition of glucose. Rapid reversible inactivation of fructose-1,6-bisphosphatase and irreversible inactivation of malate dehydrogenase were additionally investigated in glycolytic block mutants. Normal inactivation kinetics were observed in mutants without catalytic activity of phosphoglucoseisomerase (E.C.5.3.1.9), phosphofructokinase (E.C.2.7.1.11), triosephosphate isomerase (E.C.5.3.1.1) and phosphoglycerate kinase (E.C.2.7.2.3). Hence, neither type of inactivation depended on the accumulation of any glucose metabolite beyond glucose-6-phosphate. Under anaerobic conditions irreversible inactivation was completely abolished in glycolytic block mutants. In contrast rapid reversible inactivation was independent of energy provided by respiration or fermentation. Reversibility of fructose-1,6-bisphosphatase inactivation was tested under conditions which prevented irreversible malate dehydrogenase inactivation. In these experiments, fructose-1,6-bisphosphatase inactivation remained reversible for at least 120 min, whereas reversibility was normally restricted to about 30 min. This indicated a common mechanism between the irreversible part of fructose-1,6-bisphosphatase inactivation and irreversible malate dehydrogenase inactivation.
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  • 174
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    Archives of microbiology 134 (1983), S. 171-174 
    ISSN: 1432-072X
    Keywords: Acetate growth medium ; Anti-microtubule agent ; Bud initiation ; Ethyl N-phenylcarbamate ; Meiosis ; Mitotic cell cycle ; Saccharomyces cerevisiae ; Sporulation induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When diploid cells of Saccharomyces cerevisiae were incubated in acetate growth media containing 2.5 mM ethyl N-phenylcarbamate (EPC), bud initiation was inhibited preferentially, and eventually overgrown, unbudded cells accumulated. During subsequent incubation, meiosis and ascospore formation occurred at high frequencies. The behavior of EPC-treated cells was essentially the same as that of cells transferred to a starvation sporulation medium. EPC thus has a pronounced effect on the mitotic growth of yeast cells, which leads to meiotic development. Our observations indicate that EPC has a decisive function in the initiation of meiosis in rich growth media.
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  • 175
    ISSN: 1432-072X
    Keywords: Nucleotide pools ; Continuous cultivation ; Synchronized growth ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract High pressure liquidd chromatography has been used to study the acid soluble nucleotide pool of Saccharomyces cerevisiae under different conditions of growth. ATP, ADP, AMP, NAD, GTP, UTP, UDP, CTP, CDP, and UDP-sugars plus UMP could be separated and were found in concentrations higher than 0.1 μmol per g yeast cell dry weight (=detection limit). During glucose-limited continuous culture the levels of individual nucleotides depended on the growth rate, which was most pronounced with pyrimidine (uridine, cytidine) nucleotides. The energy charge (E.C.) remained high (0.9) at all growth rates (0.07–0.3 h-1). During synchronized growth at a constant growth rate (0.11 h-1) almost all nucleotide levels and the E.C. remained at constant values with the only exception of UDP-sugars and UMP of which increased levels were found during the phase of budding. Under conditions of metabolic stress (addition of antimycin A, deoxyglucose plus iodoacetate) pronounced changes in the levels of purine (adenine and guanine) nucleotides and the E.C. were observed. All other nucleotides were less influenced by these conditions. Only under these conditions IMP accumulation was observed. The results strongly argue against the significance of purine nucleotide or E.C. measurements under viable conditions. In contrast, changes in the levels of pyrimidine nucleotides seem to be indicative of changes in the flux through the metabolic pathways where they act as coenzymes.
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  • 176
    ISSN: 1432-072X
    Keywords: Induction ; Catabolic repression ; galactose metabolism ; Yeast
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Induction and repression kinetics of alphagalactosidase, galactose uptake system and Leloir pathway enzymes were studied in chemostat cultures by changing the medium feed from glucose (11 mM) to glucose and galactose (11 mM; 17 mM respectively) in the induction experiments; and from galactose (11 mM) or (111 mM) to galactose plus glucose (83 mM) in the repression experiments. Basal levels of alpha-galactosidase and glucose uptake could be estimated in glucose-limited yeast cells, but it was not possible to detect any glactose pathway enzyme activity. In the repression experiments under galactose-limited or galactose-sufficient yeast cells, alpha-galactosidase and galactokinase decayed with K d=-0.21h-1=-D; that is, synthesis of these enzymes ceased (catabolite repression). In contrast transferase and epimerase activities and galactose uptake, decreased with K d values of-0.33 and-0.54h-1, showing that these activities were also subject to catabolite inactivation.
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  • 177
    ISSN: 1432-072X
    Keywords: Nitrobacter hamburgensis ; Nitrite oxidoreductase ; Nitrate reductase ; Molybdenum iron-sulfur protein ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrite oxidoreductase, the essential enzyme complex of nitrite oxidizing membranes, was isolated from cells of the nitrifying bacterium Nitrobacter hamburgensis. The enzyme system was solubilized and purified in the presence of 0.25% sodium deoxycholate. Nitrite oxidoreductase oxidized nitrite to nitrate in the presence of ferricyanide. The pH optimum was 8.0, and the apparent K m value for nitrite amounted to 3.6 mM. With reduced methyl-and benzylviologen nitrite oxidoreductase exhibited nitrate reductase activity with an apparent K m value of 0.9 mM for nitrate. NADH was also a suitable electron donor for nitrate reduction. The pH optimum was 7.0. Treatment with SDS resulted in the dissociation into 3 subunits of 116,000, 65,000 and 32,000. The enzyme complex contained iron, molydbenum, sulfur and copper. A c-type cytochrome was present. Isolated nitrite oxidoreductase is a particle of 95±30 Å in diameter.
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  • 178
    ISSN: 1432-072X
    Keywords: cAMP ; Cat mutants ; Glucose repression ; Glucose-induced ; Intracellular pH ; Ras ; Saccharomyces cerevisiae ; Signal transduction ; Trehalase ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Addition of glucose to derepressed cells of the yeast Saccharomyces cerevisiae induces a transient, specific cAMP signal. Intracellular acidification in these cells, as caused by addition of protonophores like 2,4-dinitrophenol (DNP) causes a large, lasting increase in the cAMP level. The effect of glucose and DNP was investigated in glucose-repressed wild type cells and in cells of two mutants which are deficient in derepression of glucose-repressible proteins, cat1 and cat3. Addition of glucose to cells of the cat3 mutant caused a transient increase in the cAMP level whereas cells of the cat1 mutant and in most cases also repressed wild type cells did not respond to glucose addition with a cAMP increase. The glucose-induced cAMP increase in cat3 cells and the cAMP increase occasionally present in repressed wild type cells however could be prevented completely by addition of a very low level of glucose in advance. In derepressed wild type cells this does not prevent the specific glucose-induced cAMP signal at all. These results indicate that repressed cells do not show a true glucose-induced cAMP signal. When DNP was added to glucose-repressed wild type cells or to cells of the cat1 and cat3 mutants no cAMP increase was observed. Addition of a very low level of glucose before the DNP restored the cAMP increase which points to lack of ATP as the cause for the absence of the DNP effect. These data show that intracellular acidification is able to enhance the cAMP level in repressed cells. The glucose-induced artefactual increase occasionally observed in repressed cells is probably caused by the fact that their low intracellular pH is only restored after the ATP level has increased to such an extent that it is no longer limiting for cAMP synthesis. It is unclear why the artefactual increases are not always observed. Measurement of glucose- and DNP-induced activation of trehalase confirmed the physiological validity of the changes observed in the cAMP level. Our results are consistent with the idea that the glucose-induced signaling pathway contains a glucose-repressible protein and that the protein is located before the point where intracellular acidification triggers activation of the pathway.
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  • 179
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Catalase A ; Catalase T ; β-Oxidation ; Microbodies ; H2O2-Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The parental strain (A+T+) of Saccharomyces cerevisiae and mutants, deficient in catalase T (A+T−), catalase A (A−T+) or both catalases (A−T−), grew on ethanol and oleic acid with comparable doubling times. Specific activities of catalase were low in glucose- and ethanol-grown cells. In the two oleic acid-grown A+-strains (A+T+ and A+T−) high catalase activities were found; catalase activity invariably remained low in the A−T+ strain and was never detected in the A−T− strain. The levels of β-oxidation enzymes in oleic acid-grown cells of the parental and all mutant strains were not significantly different. However, cytochrome C peroxidase activity had increased 8-fold in oleic acid grown A− strains (A−T+ and A−T−) compared to parental strain cells. The degree of peroxisomal proliferation was comparable among the different strains. Catalase A was shown to be located in peroxisomes. Catalase T is most probably cytosolic in nature and/or present in the periplasmic space.
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  • 180
    ISSN: 1432-072X
    Keywords: Intercellular junctions ; Multicellularity in prokaryotes ; Bacterial magnetotaxis ; Ultrastructure ; Bacterial co-ordination
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    Topics: Biology
    Notes: Abstract A many-called magnetotactic prokaryote obtained from brackish water was observed to possess intercellular connections at points of contact between the outer membranes of constituent cells. Each aggregate organism consisted of 10 to 30 individual Gram-negative cells containing material with the appearance of poly-β-hydroxybutyrate and magnetosomes of unusual arrangement, structure and composition. The aggregate, which possessed prokaryotic-type flagella arranged at the outwards surfaces of each cell, showed motility indicative of co-ordination between individual component cells. These results suggest that this organism could be a multicellular prokaryote.
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  • 181
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    Archives of microbiology 134 (1983), S. 270-275 
    ISSN: 1432-072X
    Keywords: Candida utilis ; Brettanomyces intermedius ; Yeast ; Glycolysis ; Vacuole ; Cytoplasm ; Phosphate compartmentation ; Phosphate transport ; Polyphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 31P NMR was used to study the dynamics of phosphate pools during substrate utilization by aerobic and anaerobic suspensions of the yeast Candida utilis and by aerobic suspensions of the yeast Brettanomyces intermedius. In both yeast, the cytoplasmic pH was monitored; in C. utilis also the vacuolar pH could be measured. When glucose was used as a substrate for C. utilis, the vacuolar store of inorganic phosphorus (both orthophosphate and polyphosphate) was mobilized to replenish cytoplasmic phosphate which had become very low due to the build-up of high sugar phosphate levels. The hydrolysis of polyphosphate was glucose-dependent; it did not occur with ethanol as the substrate. After glucose depletion resynthesis of polyphosphate occurred only under aerobic conditions; anaerobic C. utilis cells continued to hydrolyze vacuolar polyphosphate. This difference between the aerobic and anaerobic suspension could be related to differences in cellular ATP levels. When ethanol was employed as a substrate, both Candida utilis and Brettanomyces intermedius exhibited a substantial increase in polyphosphate levels. These observations suggested a dual role for polyphosphate in yeasts both as a phosphate and an energy store. The cytoplasmic pH in C. utilis displayed characteristic responses to metabolic changes during glucose degradation. B. intermedius experienced a strong cytoplasmic acidification upon ethanol utilization due to acetic acid formation. The mechanism of transport of Pi across the vacuolar membrane in C. utilis appeared to be different from that reported for the plasma membrane.
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  • 182
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    Archives of microbiology 134 (1983), S. 295-298 
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
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    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
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  • 183
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
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  • 184
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    Archives of microbiology 130 (1981), S. 87-89 
    ISSN: 1432-072X
    Keywords: Yeast ; Kluyveromyces ; 6-Deoxyglucose ; Glucose transport
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    Topics: Biology
    Notes: Abstract The inducible glucose transport system of the yeast, Kluyveromyces lactis, was studied using the nonmetabolizeable glucose analogue, 6-deoxyglucose. The free sugar analogue is transported into glucose-grown cells via a facilitated diffusion system as determined by the nonconcentrative uptake of the sugar analogue, by the failure of energy inhibitors to reduce the rate of transport and by exchange diffusion across the membrane. Free 6-deoxyglucose is also transported into succinate-grown cells passively. Induction experiments revealed that 6-deoxyglucose serves as a gratuitous inducer for the glucose transport system in this yeast.
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  • 185
    ISSN: 1432-072X
    Keywords: Glycoprotein ; Inducible strains ; Saccharomyces cerevisiae ; Sexual agglutinability ; Tunicamycin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of tunicamycin (TM) on the sexual agglutinability and zygote formation of Saccharomyces cerevisiae were studied using the two kinds of haploid strains, inducible and constitutive for sexual agglutinability. Induction of sexual agglutinability by opposite mating type sex pheromone of inducible strains was inhibited by TM in α mating type but not in a mating type. The recovery by temperature-shift-down from the temperature-suppressed sexual agglutinability of constitutive strains was enhanced by TM in a mating type but rather inhibited in α mating type. Pretreatment with TM of constitutive strains enhanced sexual agglutinability in a mating type but not in α mating type. The above-mentioned a-mating-type-specific agglutinability-enhancing actions of TM were discussed in relation to the action mechanism of α pheromone which induces or enhances the sexual agglutinability of a cells. Zygote formation was inhibited by TM in both constitutive and inducible strains at concentrations which showed only partially inhibitory effect on sexual agglutinability.
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  • 186
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    Archives of microbiology 153 (1990), S. 384-391 
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Ethanol ; Acetic acid ; Cytoplasmic pH ; 31P-NMR ; 13C-NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell suspensions of a respiratory deficient mutant of Saccharomyces cerevisiae were monitored by in vivo 31P and 13C Nuclear Magnetic Resonance in order to evaluate the effect of ethanol in intracellular pH and metabolism. In the absence of an added energy source, ethanol caused acidification of the cytoplasm, as indicated by the shift to higher field of the resonance assigned to the cytoplasmic orthophosphate. Under the experimental conditions used this acidification was not a consequence of an increase in the passive influx of H+. With cells energized with glucose, a lower value for the cytoplasmic pH was also observed, when ethanol was added. Furthermore, lower levels of phosphomonoesters were detected in the presence of ethanol, indicating that an early event in glycolysis is an important target of the ethanol action. Acetic acid was identified as responsible for the acidification of the cytoplasm, in experiments where [13C]ethanol was added and formation of labeled acetic acid was detected. The intracellular and the extracellular concentrations of acetic acid were respectively, 30 mM and 2 mM when 0.5% (120 mM) [13C]ethanol was added.
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  • 187
    ISSN: 1432-072X
    Keywords: Regulatory mutants ; Meiotic mapping ; Transcriptional regulation ; MAL genes ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract The MAL1 locus of Saccharomyces cerevisiae comprises three genes necessary for maltose utilization: a regulatory (MALR), a maltose transport (MALT) and a maltase gene (MALS). A fine structure genetic map of the MAL1R gene was constructed and the order of mutations was confirmed by plasmid-mediated chromosomal recombination. The mutations cluster non-randomly within the 5′ half of the gene, where the putative DNA binding domain of the encoded protein is located. Only mutations mal1 R-22 and MAL1R-72 map in the 3′ terminal half of the gene; these mutations cause a different pattern of transcriptional regulation of plasmid-borne MAL6T genes. Experiments supporting a direct involvement of the MALR-encoded protein in carbon catabolite repression of MAL gene expression are reported.
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  • 188
    ISSN: 1573-4919
    Keywords: bovine heart fatty acid-binding protein ; H-FABPc ; heterologous gene expression ; Saccharomyces cerevisiae ; GALIO promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The unicellular eukaryotic microorganism, Saccharomyces cerevisiae, transformed with a plasmid containing a cDNA fragment encoding bovine heart fatty acid-binding protein (H-FABP) under the control of the inducible yeast GAL10 promoter, expressed FABP during growth on galactose. The maximum level of immunoreactive FABP, identical in size to native protein as judged from SDS-polyacrylamide gel electrophoresis, was reached after approximately 16 hours of induction. Analysis of particulate and soluble subcellular fractions showed that FABP was exclusively associated with the cytosol. FABP expressed in yeast cells was functional as was demonstrated by its capacity to bind 14C-oleic acid in an in vitro assay. Growth of the transformants on galactose as the carbon source was significantly retarded at 37°C. Whereas the fatty acid pattern of total lipids was not altered in transformed cells, desaturation of exogenously added 14C-palmitic acid was significantly reduced both at 30 and 37°C. The lowest percentage of radioactively labeled unsaturated fatty acids was found in the phospholipid fraction.
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  • 189
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    Journal of chemical ecology 10 (1984), S. 1425-1433 
    ISSN: 1573-1561
    Keywords: Social wasp ; Polistes exclamans ; Polistes fuscatus ; Vespidae ; Hymenoptera ; venom ; alarm pheromone ; alarm behavior
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The venoms ofPolistes exclamans andP. fuscatus elicit alarm behavior and attract attacking wasps. The response is not species specific, for both hetero- and conspecific venoms elicit similar responses in both species. A test in a wind tunnel provided no support for the hypothesis that alarmed wasps release an alarm pheromone on the nest.
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  • 190
    ISSN: 1573-1561
    Keywords: Kairomone ; 2-acylcyclohexane-1,3-diones ; ovipositionEphestia kuehniella Zeller [syn.Anagasta kuehniella (Zeller)] ; Lepidoptera ; Pyralidae ; Nemeritis canenscens (Grav.) [syn.Venturia canescens (Grav.)] ; Hymenoptera ; Ichneumonidae
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relative activities of sixteen 2-acylcyclohexane-1,3-diones from the larval mandibular glands ofEphestia (=Anagasta) kuehniella Zeller in causing the parasiteNemeritis (=Venturia) canescens (Grav.) to make oviposition movements are reported.
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  • 191
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    Journal of chemical ecology 10 (1984), S. 1787-1798 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Curculionidae ; Otiorhynchus sulcatus (F.) ; black vine weevil ; Ericaceae ; Rhododendron ; trichomes ; glandular scales ; essential oils ; volatiles ; plant resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Glandular scales on selected lepidote rhododendron species varied in density from 109 ± 13 to 4180 ± 60/cm2 of leaf surface. Globules contained within the scales stained with Sudan IV, a lipophilic dye. Essential oil contents of the scales varied with species from 24 ± 8 to 151 ± 35 ng/scale. Black vine weevil [(Otiorhynchus sulcatus (F.)] feeding on leaves from a sample of rhododendron species was inversely related to leaf essential oil content, and weevil feeding on membrane filters was inhibited by application of essential oil extracts from leaves of most lepidote rhododendrons tested. Results suggest that the glandular scales of the lepidote rhododendrons function, at least in part, in plant defense against insects.
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  • 192
    ISSN: 1573-1561
    Keywords: Leptopilinaheterotoma ; Hymenoptera ; Eucoilidae ; Saccharomyces cerevisiae ; host-habitat searching ; chemoreception ; fermentation products ; ethanol ; ethyl acetate ; acetaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemical stimuli play an important role in the process of searching for a host habitat by parasitic wasps. Volatile compounds originating from host habitats and/or hosts are the cues that enable such a location.Leptopilina heterotoma, a larval parasite ofDrosophila, is attracted to the food of its host, baker's yeast. Analysis of the fermentation products of baker's yeast, using a mass spectrometer, and olfactometer studies indicate that three fermentation products of this yeast, the main component of the host habitat in our laboratory, attractL. heterotoma: ethanol (5%), ethyl acetate (10−2, 10−3%), and acetaldehyde (1%). A combination of these three compounds, however, cannot compete with baker's yeast in attracting the parasites. Thus other factors, such as different compounds, concentrations, and/or combinations, also, play a role and remain to be tested.Leptopilina heterotoma does not use host-related olfactory cues in long-distance habitat location as it cannot distinguish between host habitat and host habitat with hosts.
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  • 193
    ISSN: 1573-1561
    Keywords: Pine sawflies ; Neodiprion spp. ; Hymenoptera ; Diprionidae ; electroantennogram ; sex pheromone ; isomers ; jack pine ; Pinus banksiana ; diprionol ; 3,7-dimethylpentadecan-2-ol ; acetate ; propionate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Several species of monophagous jack pine sawflies (Hymenoptera: Diprionidae) were tested in the field and by electroantennograms (EAG) for activity toward the optical isomers of a pine sawfly sex pheromone, the acetate and propionate esters of 3,7-dimethylpentadecan-2-ol.Neodiprion rugifrons andNeodiprion dubiosus were attracted to a mixture of the propionate esters of the 2S,3R,7R and 2S,3R,7S isomers, whereasNeodiprion swainei was attracted to the 2S,3S,7S propionate isomer. Samples containing the 2S,3R,7S propionate isomer elicited the strongest EAG responses in these three species andNeodiprion nigroscutum. The 2S,3S,7S propionate isomer was equally active (EAG) in the case ofN. swainei.
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  • 194
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    Journal of chemical ecology 10 (1984), S. 723-752 
    ISSN: 1573-1561
    Keywords: Ips typographus ; pheromone ; release ; recapture ; diffusion ; model ; Coleoptera ; Scolytidae ; trap ; marking ; dispersal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The movement of bark beetles near an attractive pheromone source is described in terms of mathematical models of the diffusion type. To test the models, two release experiments involving 47,000 marked spruce bark beetles [Ips typographus (L.)] were performed. The attractive source was a pheromone trap, surrounded by eight concentric rings with eight passive trap stations on each ring. Captures were recorded every 2–10 minutes for the pheromone trap and once for the passive traps. The models were fitted to the distribution in time of the central pheromone trap catch and to the spatial distribution of catch among the passive traps. The first model that gives a reasonable fit consists of two phases: Phase one—After release the beetles move according to a diffusion process with drift towards the pheromone trap. The strength of the drift is inversely proportional to the distance from the traps. Phase two—those beetles attracted to, but not caught by, the pheromone trap are no longer influenced by the pheromone, and their movement is described by a diffusion process without drift. In phase two we work with a loss of beetles, whereas the experiment seems to indicate that the loss of beetles in phase one is negligible. As a second model, the following modification of phase one is considered: After release the beetles move according to a diffusion process without drift, until they start responding to the pheromone (with constant probability per unit time), whereafter they start moving according to a diffusion process with drift. This study, like other release experiments, shows that the efficiency of the pheromone trap is rather low. What is specific for the present investigation is that we try to explain this low efficiency in terms of dynamic models for insect movement. Two factors seem to contribute: Some beetles do not respond to pheromone at all, and some beetles disappear again after having been close to the pheromone trap. It also seems that the motility of the beetles decreased after they ceased responding to the pheromone. Furthermore, the data lend some support to the hypothesis that flight exercise increases the response of the beetles to pheromone.
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  • 195
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    Journal of chemical ecology 10 (1984), S. 759-769 
    ISSN: 1573-1561
    Keywords: Ips typographus ; Dendroctonus micans ; Coleoptera ; Scolytidae ; exo-brevicomin ; (+)-ipsdienol ; single-cell recordings ; interspecific attraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Olfactory receptor cells were studied electrophysiologically inIps typographus andDendroctonus micans. The investigation revealed cells which were keyed to pheromone compounds characteristic of the reciprocal genus. Thus, cells keyed toexo-brevicomin were found inI. typographus, whereas cells keyed to (+)-ipsdienol were present inD. micans. Laboratory behavioral tests indicated an attractive effect of the two compounds on beetles of the reciprocal genus. InI. typographus the effect ofexo-brevicomin predominantly concerned males and enhanced their response to the pheromone “ipslure.” It is suggested thatexo-brevicomin serves as an interspecific attractant forI. typographus, which may be guided by pheromone compounds of the reciprocal genus in finding suitable breeding material. The function of (+)-ipsdienol inD. micans is more uncertain. It may be either a pheromone or an interspecific messenger.
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  • 196
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    Journal of chemical ecology 10 (1984), S. 1759-1785 
    ISSN: 1573-1561
    Keywords: Cotton boll weevil ; Anthonomus grandis ; Coleoptera ; Curculionidae ; pheromone ; kairomone ; plant odor ; olfaction ; electroantennogram ; attractant ; host plant ; green leaf volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennogram (EAG) techniques were utilized to measure the antennal olfactory responsiveness of adult boll weevils,Anthonomus grandis Boh. (Coleoptera: Curculionidae), to 38 odorants, including both insect and host plant (Gossypium hirsutum L.) volatiles. EAGs of both sexes were indicative of at least two receptor populations: one receptor population primarily responsive to pheromone components and related compounds, the other receptor population primarily responsive to plant odors. Similar responses to male aggregation pheromone components (i.e., compounds I, II, and III + IV) were obtained from both sexes, but females were slightly more sensitive to I. Both sexes were highly responsive to components of the “green leaf volatile complex,” especially the six-carbon saturated and monounsaturated primary alcohols. Heptanal was the most active aldehyde tested. More acceptors responded to oxygenated monoterpenes than to monoterpene hydrocarbons. β-Bisabolol, the major volatile of cotton, was the most active sesquiterpene. In general, males, which are responsible for host selection and pheromone production, were more sensitive to plant odors than were females. In fact, males were as sensitive to β-bisabolol and heptanal as to aggregation pheromone components. Electrophysiological data are discussed with regard to the role of insect and host plant volatiles in host selection and aggregation behavior of the boll weevil.
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  • 197
    ISSN: 1573-1561
    Keywords: Ips typographus ; spruce bark beetle ; Coleoptera ; Scolytidae ; 2-methyl-3-buten-2-ol ; ipsenol ; cis-verbenol ; ipsdienol ; trans-verbenol ; verbenone ; myrtenol ; trans-myrtanol ; 2-phenylethanol ; ß-isophorone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ips typographus beetles were collected in the field, separated into eight attack phases (from beetles walking on the trunk of a tree under attack to those excavating gallery systems with a mother gallery longer than 4 cm), and immediately frozen in liquid nitrogen. 2-Methyl-3-buten-2-ol,cis- andtrans-verbenol, verbenone, myrtenol, trans-myrtanol, ipsenol, ipsdienol, and 2-phenylethanol were quantified from excised hindguts against an internal standard, heptyl acetate, in the extraction solvent. Methylbutenol, the pinene alcohols, and 2-phenylethanol showed the same pattern of variation between attack phases in males, with the largest amounts present before accepting females and then a fast decline. Ipsenol and ipsdienol were not detected in males before the females were accepted, and the amounts increased when the females start their egg laying. Verbenone occurred only in trace amounts. The beetles were sampled from five Norway spruce trees (Picea abies) of differing resin flow. The correlations between the nine pheromone components and five major host monoterpenes in the gut showed that the variation in the amount of methyl-butenol, ipsenol, and ipsdienol could not be explained by the variation in the amounts of host monoterpenes. In contrast over 80% of the quantitative variation ofcis-verbenol,trans-verbenol, and myrtenol was explained by the amount of α-pinene. The nine pheromone components from 36 individual males were also quantified. Both methylbutenol andcis-verbenol showed a large variation in both amounts and proportions. Females containedtrans-verbenol and traces of most other components found in males. When accepted by the male, they also contained a female-specific compound, β-isophorone. Behavioral and biosynthetic implications of the results are discussed.
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  • 198
    ISSN: 1573-1561
    Keywords: Pheromone ; pinyon pine ; bark beetle ; cross-attraction ; Ips hoppingi ; Ips confusus ; Coleoptera ; Scolytidae ; Pinus discolor ; Pinus edulis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Females of a pinyon pine bark beetle,Ips hoppingi Lanier, were less attracted by the aggregation pheromone produced by conspecific males than by the pheromone produced by the neighboring sibling species,I. confusus (LeConte). Cross-attraction was elicited by males infesting the regional pinyon pine hosts (P. discolor andP. edulis) of eitherIps species in south-eastern Arizona. Pheromonal specificity has not accompanied speciation in this species pair.
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  • 199
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    Journal of chemical ecology 16 (1990), S. 3383-3392 
    ISSN: 1573-1561
    Keywords: Monochamus alternatus Hope ; Coleoptera ; Cerambycidae ; female ; Pinus densiflora ; Pinus thunbergii ; attractants ; (+)-juniperol ; (+)-pimaral ; sesquiterpenes ; diterpenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A sesquiterpene and a diterpene were isolated from sound pines and identified as (+)-juniperol and (+)-pimaral, respectively. The combination of these compounds in a certain ratio induced a significant laboratory flight response by the female cerambycid beetle,Monochamus alternatus Hope. Individual compounds elicited a limited response only.
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  • 200
    ISSN: 1573-1561
    Keywords: Enantiomer discrimination ; male patrolling ; odor marking ; Hymenoptera ; Apoidea ; Andrena wilkella ; bee ; EAG ; spiroacetal ; absolute configuration ; 2,8-dimethyl-1,7-dioxaspiro[5.5]undecane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diastereomers of the spiroacetal, 2,8-dimethyl-1,7-dioxaspiro [5.5]undecane, represent main components of the cephalic secretion from males of the solitary bee,Andrena wilkella. The major compound proved to be of high enantiomeric purity, showing (2S,6R,8S) configuration. Only the naturally occurring enantiomer attracted patrolling males in the field; its antipode was behaviorally inactive and in a racemic mixture did not inhibit response. The (E,Z) diastereomers were also found to be almost inactive. EAG studies gave the same result as the behavioral tests. The biological function of the spiroacetal is discussed in view of the evolution of the mating behavior inA. wilkella.
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