Cell, 1980 Feb, 19(2), 339 - 43 The tRNAAGYSer and tRNACGYArg genes from a gene cluster in yeast mitochondrial DNA; Martin NC et al.; Yeast mitochondrial DNA-pBR322 recombinant DNA molecules screened for rRNA genes were used as a source of DNA for mitochondrial tRNA gene sequence analysis . We report here the sequences of yeast mitochondrial tRNA genes coding for a tRNAAGYSer and a tRNACGYArg . The tRNAAGYSer sequence deduced from the gene is the first reported sequence of a yeast tRNAAGYSer . It is also the second yeast mitochondrial tRNASer gene to be sequenced, and demonstrates unequivocally the presence of mitochondrial encoded serine tRNA isoacceptors . The tRNACGYArg sequence deduced from the gene is the most AT-rich (82%) tRNA sequence ever reported . Whereas all the mitochondrial genes sequenced to date exist singly on the genome and are separated by long stretches of AT-rich DNA, the tRNAACYSer and tRNAcgyarg genes exist in tandem, separated by only 3 bp . This gene arrangement strongly suggests that mitochondrial tRNA genes may be transcribed into multicistronic precursors. Biochim Biophys Acta, 1980 Jan 11, 611(1), 99 - 113 Effects of free magnesium and alkali ions on the conformation and glucose-binding strength of yeast hexokinase isozymes; Norton GE et al.; Titrations of the tryptophan fluorescence of yeast hexokinase (ATP:D-hexose 6-phosphortransferase, EC 2.7.1.1.) isozymes P-I (A) and P-II (B) were performed with Mg2+, Li+, Na+ and K+ as titrant in absence and in presence of glucose, and vice versa, at pH 8.3 and 5.5 at 20 degrees C . Mg2+ quenches the fluorescence of surface tryptophan primarily and does so by producing a conformational change which alters the microenvironment of the tryptophan . For both isozymes Mg2+ exerts a specific ion effect, i.e . significantly larger than the ionic strength (I) effect, which enhances the glucose quenching by causing a conformation change which increases the glucose-binding constant . For the P-I isozyme glucose binding exhibits positive cooperativity at both pH 8.3 and 5.5 when the ionic strength (I) is low, i.e . significantly larger than the ionic strength (I) effect, which enhances the glucose quenching by causing a conformation change which increases the glucose-binding constant . For the P-I isozyme glucose binding exhibits positive sooperativity at both pH 8.3 and 5.5 when the ionic strength (I) is low, i.e . 0.04 or less, regardless of which of the above four cations is present . For P-II, however, glucose binding is non-cooperative at pH 8.3 regardless of I or the cation species and at pH 5.5 and low I with K+ or Mg2+ as the predominant cation present, but there is apparent negative cooperativity at pH 5.5 and low I when Na+ or Li+ predominates . These results are discussed in terms of known structural characteristics of the isozymes. Nature, 1980 Jan 10, 283(5743), 218 - 20 Excision sequences in the mitochondrial genome of yeast; Gaillard C et al.; It is well established that spontaneous cytoplasmic 'petite' mutants of Saccharomyces cerevisiae have mitochondrial genome units in which an excised segment of the parental wild-type genome has been tandemly amplified (Fig . 1), so that the excised segment becomes the repeat unit of the petite genome; the latter may in turn undergo further deletions leading to secondary petite genomes having shorter repeat units (see ref . 1 for a brief review) . Recent investigations on the mitochondrial genomes of several spontaneous petite mutants have shown that frequently the ends of the excised segment correspond to short sequences of the wild-type genome which are extremely rich in GC, the GC clusters; alternatively, they seem to be located in the long AT-rich stretches, the AT spacers, which form at least half of the genome . As sequence repetitions have been demonstrated in both GC clusters and AT spacers, it is very likely that excision takes place by a mechanism involving illegitimate site-specific recombination events between homologous sequences, as previously postulated . We show here that the sequences involved in the excision of a particular spontaneous petite genome are direct nucleotide repeats located in the AT spacers. J Biol Chem, 1980 Jan 10, 255(1), 12 - 5 Interaction of a new polypeptide with yeast RNA polymerase B; Sawadogo M et al.; A basic 37,000-dalton protein (P37), purified from yeast cells, interacts with yeast RNA polymerase B and drastically increases its specific activity . A complex of P37 and RNA polymerase can be isolated by sedimentation through a glycerol gradient . The complex is dissociated at the ionic strength of 0.9 . The preferential binding of P37 with RNA polymerase form BI (with the unproteolyzed B220 subunit) was visualized by polyacrylamide gel electrophoresis under nondenaturing conditions . Kinetic analysis of the RNA polymerase cofactor interaction indicated that the dissociation constant for the complex is 5 X 10(-8) M. Antonie Van Leeuwenhoek, 1980, 46(2), 129 - 41 An electron microscopical study of the development of peroxisomes during formation and germination of ascospores in the methylotrophic yeast Hansenula polymorpha; Veenhuis M et al.; Ascospore formation was studied in liquid cultures of the yeast Hansenula polymorpha, previously grown under conditions in which the synthesis of alcohol oxidase was repressed (glucose as growth substrate) or derepressed (methanol, glycerol and dihydroxyacetone as growth substrates and after growth on malt agar plates) . In ascospores obtained from repressed cells, generally one small peroxisome was present . The organelle probably originated from the small peroxisome, originally present in the vegetative cells . They had no crystalline inclusions and cytochemical experiments indicated the presence of catalase, urate oxidase and amino acid oxidase activities in these organelles . In ascospores obtained from derepressed cells, generally 1--3 crystalline peroxisomes were observed . These organelles also originated from the peroxisomes originally present in the vegetative cells by means of fragmentation or division . They contained, in addition to the enzymes characteristic for peroxisomes in spores from repressed cells, also alcohol oxidase . The latter enzyme is probably responsible for the crystalline substructure of these peroxisomes . Peroxisomes had no apparent physiological function in the process of ascosporogenesis . A glyoxysomal function of the organelles during germination of the ascospores was also not observed . Germination of mature ascospores in media containing different sources of carbon and nitrogen showed that the function of the peroxisomes present in ascospores of Hansenula polymorpha is probably identical to that in vegetative haploid cells . They are involved in the oxidative metabolism of different carbon and nitrogen sources . Their enzyme profile is a reflection of that peroxisomes of vegetative cells and their presence may enable the formation of cells which are optimally adapted to environmental conditions extant during spore germination. Can J Microbiol, 1980 Jan, 26(1), 36 - 49 Morphogenesis and wall chemistry of the yeast, "intermediate," and hyphal phases of the dimorphic fungus, Mycotypha poitrasii; Cole GT et al.; When Mycotypha poitrasii (Zygomcetes) is grown under standard conditions in liquid culture containing 1% polypeptone, 0.5% yeast extract, and variable glucose concentrations (0-6%), it displays mycelial--yeast conversion . "Intermediate" cells, isolated from cultures containing 2% glucose, are considered to represent a developmental phase in the process of morphogenesis . Distinct differences in the morphology and wall chemistry of the intermediate cells were demonstrated when compared to the yeast and hyphal forms . It is suggested that the trends evident from these comparative analyses reflect relationships between the alterations in cell wall chemistry and morphogenetic aspects of dimorphism. Antonie Van Leeuwenhoek, 1980, 46(6), 517 - 21 The yeast genus Yarrowia gen . nov; van der Walt JP et al.; The ascigerous teleomorph of Candida lipolytica (Harrison) Diddens at Lodder, previously classified as Endomycopsis lipolytica Wickerman et al . and as Saccharomycopsis lipolytica (Wickerham et al.) Yarrow, has been assigned to the new genus Yarrowia . Yarrowia lipolytica (Wickerham et al.) comb . nov . is the type species for the genus . The remaining species of Saccharomycopsis are revised. Can J Microbiol, 1980 Jan, 26(1), 64 - 70 Physiology of Candida utilis yeast in zinc-limited chemostat culture; Lawford HG et al.; Candida utilis NRRLY -900 was grown in aerobic continuous culture in a minimal salts medium with sucrose (1% w/v) as the carbon source . increasing the concentration of zinc in the medium from 2.3 microM results in an increase in the apparent critical dilution rate from 0.3 to 0.47h-1, and in the maximum biomass productivity form 1.5g dry weight per litre per hour (at D=0.33-1) to 2.56g per litre per hour (at D = 0.45-1) . The maximum steady-state level of cell-associated zinc (at D = 0.4-1) is 4nmol Zn2+/mg dry weight, during carbon-limited growth, and about 9mumol Zn2+/mg dry weight when FeCI3 is omitted form the medium . At input zinc concentrations <20microM, the cellular zinc concentration decreases linearly in proportion to the input zinc concentration and at <4.5microM Zn2+ the culture becomes zinc-limited . Zinc-limitation results in a decrease iun the growth yield Ysurcosefrom 0.54 to 0.38 cells/g sucrose consumed, and Y0 from 22 to 13g cells/g-atom 02, suggesting an altered efficiency of energy metabolism . The composition of the culture biomass with respect to protein and RNA content is not affected by zinc limitation. Nucleic Acids Symp Ser, 1980, (7), 325 - 33 Synthesis of 3'-half molecule (nucleotides 36-76) of yeast alanine transfer ribonucleic acid; Wang DB; We have successfully ligated the 12 nucleotide fragment (nucleotides 46-57) with the p19p nucleotide fragment (nucleotides 58-76) to form a 31p nucleotide fragment (nucleotides 46-76) which after 5'-phosphorylation was in turn joined to the 10 nucleotide fragment (nucleotides 36-45) to give the 3'-half molecule of yeast alanine tRNA. Basic Life Sci, 1980, 15, 85 - 120 Genetic and physiological factors affecting repair and mutagenesis in yeast; Lemontt JF; Current views of DNA repair and mutagenesis in the yeast Saccharomyces cerevisiae are discussed in the light of recent data and with emphasis on the isolation and characterization of genetically well-defined mutations that affect DNA metabolism in general (including replication and recombination) . Various "pathways" of repair are described, particularly in relation to their involvement in mutagenic mechanisms . In addition to genetic control, certain physiological factors such as "cell age," DNA replication, and the regulatory state of the mating-type locus are shown to also play a role in repair and mutagenesis. Mol Gen Genet, 1980, 180(3), 605 - 7 Mapping of a centromere-linked gene responsible for constitutive acid phosphatase synthesis in yeast; Lange P et al.; From a chemostat in which the activity of acid phosphatase was limiting, a mutant with a constitutive acid phosphatase was selected . This gene (pho80) responsible for the production of a repressor was mapped 5.3 centimorgans apart from the centromere on the right arm of chromosome XV. Radiat Environ Biophys, 1980, 18(1), 45 - 55 Combined action of ultrasound and ionizing radiation on yeast cells; Petin VG et al.; This communication reports the observation of synergistic relationships between ultrasound and gamma-irradiation of stationary phase cultures of Saccharomyces cerevisiae of different strains . The gamma-ray dose was applied before or after the sound . The extent of synergism depended upon the sequence of application; it was smaller for (US + gamma-ray)-exposure in comparison with gamma-ray +US)-treatment . The combined action of both modalities had smaller or no synergistic effect for mutant(rad51) yeast cells incapable of recovery . On this basis, it was concluded that possible mechanisms for ultrasound radiosensitization of yeast cells may involve the reduced capacity of cells to recover damages resulted from the combined action and/or the enhanced expression of lethal damage. Radiat Environ Biophys, 1980, 18(1), 19 - 26 Cellular radiation effects and hyperthermia: cytokinetic investigations with stationary phase yeast cells; Fingerhut R et al.; Wild type diploid yeast, Saccharomyces cerevisiae strain 211, was subjected to 250 kV X-rays or 50 degrees C heat treatment for 30 min or to a combination of both . X-ray exposure took place either in air or in nitrogen . Cell number, percentage of budding cells and cell cycle progression was followed for up to 12 h post irradiation . The distribution of cell cycle stages was determined by flow cytofluorometry . All treatments cause a retardation of cell division rate . Hyperthermia leads mainly to a lengthening of G1, whereas X-rays arrest the cells reversibly in G2 . The effect of the combined treatment appears to be merely additive . No . selective action of hyperthermia on hypoxic cells was found. Genetika, 1980, 16(1), 95 - 102 {Effect on cell genotype on thermal radiosensitization of yeast}; Petin VG et al.; The combined action of hyperthermia and ionizing radiation on the arrival of isogenic haploid and diploid yeast cells of wild type and rad51 mutant was studied . The experiments demonstrated the essential enhancement of radiosensitivity of diploid wild type cells is hyperthermic conditions . For haploid wild type cells and rad51 mutant cells the enhancement was smaller and negligible respectively . The action of both factors on rad51 homozygous diploid cells was additive . It is established that diploid cells were less thermosensitive than haploid ones . Rad51 mutation does not change these properties . It was concluded that the enhancement of radiosensitivity of cells under hyperthermic conditions depends on cell genotype and may be caused by the reduced capacity of cells to recover the radiation damages inflicted by the both modalities. Folia Microbiol (Praha), 1980, 25(5), 418 - 23 Design of a growth model for yeast; L'Homme C et al.; The study of the cell cycle of a yeast strain made it possible to define two parameters: T, the time elapsing between the appearance of two consecutive buds on a mother cell, and theta, the time elapsing between the appearance of a bud and the beginning of the first mitotic cycle . The influence of these two parameters on the growth rate of the strain is studied. Microbios, 1980, 27(107), 33 - 40 The partial purification, separation, and properties of yeast killer toxins; Extremera AL et al.; Two different kinds of yeast killer toxins (YKT) have been partially concentrated and their properties and molecular behaviour comparatively studied . The toxin of the first system (YKT1) shows more sensitivity to several agents (temperature, pH, enzymes) than the toxin of the second system (YKT2) . YKT1 shows only one chromatographic band on Sephadex G-200, while YKT2 shows two bands . The molecular weights of these bands have been estimated . Both toxins can be separated by isoelectrofocusing and show estimated isoelectrical points of 5.4 (YKT1) and 4.3 (YKT2). Prep Biochem, 1980, 10(3), 331 - 45 Alternate procedure for the preparation of the coenzyme A-synthesizing protein complex of Bakers' yeast; Tarnowski SJ et al.; The coenzymes A-synthesizing protein complex (CoA-SPC) of Bakers' yeast synthesizes coenzyme A in an in vitro system from the precursors ATP, D-pantothenic acid and L-cysteine . CoA-SPC has been produced on a small scale by freezing Bakers' yeast cells in a mixture of diethyl ether and solid CO2, followed by a thawing period, and subsequent removal of the diethyl ether by vacuum . The resulting yeast lysate was then stirred for 18 h in the presence of t-Factor to solubilize CoA-SPC . When a greater quantity of CoA-SPC was needed, the danger associated with the use of a large volume of diethyl ether was apparent . Therefore, the freezing step involving diethyl ether and solid CO2 has been replaced by a process of slowly drying fresh Bakers' yeast until approximately 34% of the initial weight of the yeast remained as dry solids . The yeast solids were ground to further disrupt the cell wall and membrane structure . The grinding step was followed by rehydration of the dry yeast solids with deionized H2O and stirring the rehydrated yeast for 18 h to solubilize CoA-SPC. Mol Gen Genet, 1980, 178(3), 633 - 7 Genetic and biochemical evidence for hexokinase PII as a key enzyme involved in carbon catabolite repression in yeast; Entian KD; Mutants with reduced hexokinase activity previously isolated as resistant to carbon catabolite repression of invertase and maltase (Zimmermann and Scheel, 1977) were allele tested with mutant strains of Lobo and Maitra (1977) which had defects in one or several of the genes coding for glucokinase and the two unspecific hexokinases . It could be demonstrated, that the mutation abolishing carbon catabolite repression had occurred in a gene allelic to the structural gene of hexokinase PII . Moreover, the defective mutant allele for hexokinase PII isolated by Lobo and Maitra (1977) was also defective in carbon catabolite repression . Neither glucokinase nor hexokinase PI showed any effect on this regulatory system . Biochemical analysis in crude extracts also showed altered kinetic properties of hexokinases in the hex1 mutants . The results directly support the hypothesis previously put forward, that one of the hexokinases is not only active as a catalytic, but also as a regulatory protein. Scand J Rheumatol Suppl, 1980, 31, 5 - 19 Methodological studies of monocyte yeast cell phagocytosis; Svensson B; Human mononuclear cells were separated in a Ficoll-Isopaque gradient and incubated in glass chambers in a medium of serum in Parker 199 . At the end of the incubation time heat-killed, not pre-opsonized yeast cells (YC) were added for phagocytosis . PA was expressed as the median number of YC per monocyte in 100 monocytes . The results of testing various modifications of this method indicate that an appropriate procedure, allowing a sufficient span for measuring 'subnormal' phagocytosis, is incubation of the monocytes in 15 per cent serum for 120 minutes followed by a further incubation with 10(7) YC (in 7.5% serum) for 30 minutes . The sources of variation in the determination of PA of a standard population was studied by analysis of variance . Based on the results of this study, suitable ways to define and express 'normal' and 'low' phagocytic activity were proposed. Scand J Rheumatol Suppl, 1980, 31, 21 - 7 Occurrence of deficient monocyte yeast cell phagocytosis in presence of rheumatic sera; Svensson B; Monocyte yeast cell phagocytosis was studied in 164 rheumatic sera . The results showed that the phagocytic activity (PA) was low in 51 per cent of SLE-sera, in 12 per cent of other connective tissue disease (CTD)-sera, in 16 percent of RA-sera but in none of 30 sera from patients with other chronic arthritides . Low PA was associated with cryoglobulinaemia and subnormal C1q, C4 and C3 in the SLE-group and with subnormal C4 and signs of extra-articular disease in the RA-group . In the CTD-group, low PA was only found in 4 cases of SLE-like syndromes, all having evidence of vasculitis . The findings suggest that low phagocytic activity in presence of rheumatic sera may be related to clinical syndromes with circulating immune complexes and/or hypocomplementaemia, most often SLE. Mol Gen Genet, 1980 Jan, 177(2), 283 - 9 Analysis of yeast ilv 1 CIS control and domain mutants; Bollon AP; We have identified a cis control region specific for the ilv 1 gene of Saccharomyces cerevisiae . Mutants designated ilv 1-OPc map in this control region located between arg 6 and ilv 1 and result in increased basal levels and constitutive synthesis of the ilv 1 gene products . Furthermore, ilv 1 mutants have been isolated in three different structural domains indicating that the ilv 1 gene may contain a functional intervening sequence specific for one of the two gene products. Proc Natl Acad Sci U S A, 1980 Jan, 77(1), 503 - 7 The RAD52 gene is required for homothallic interconversion of mating types and spontaneous mitotic recombination in yeast; Malone RE et al.; The rad52-1 mutation prevents homothallic mating type interconversion and reduces mitotic recombination in yeast . It has been previously reported that rad52-1 abolishes meiotic recombination . These data suggest either that a generalized recombination function(s) is required for mating type switching or that generalized recombination and specific homothallic functions are jointly controlled by the RAD52 gene . The rad52-1 mutation affects the interconversion of the two yeast mating types (a and alpha) differently, suggesting that the interconversion process is not equivalent for both mating types . This type of asymmetry is not predicted by current models of homothallic switching. J Biochem (Tokyo), 1980 Jan, 87(1), 89 - 100 Chromatography in presence of high concentrations of salts on columns of celluloses with and without ion exchange groups (hydrogen bond chromatography) . Its application to purification of yeast enzymes; Fujita T et al.; 1 . All the water-soluble yeast enzymes tested, which were only partially precipitated at best in the presence of high concentration of salts such as ammonium sulfate or sodium formate, were adsorbed on a column of cellulose in the presence of the same concentrations of the salts, and the adsorbed enzymes were chromatographically eluted by decreasing the concentration of the salts . 2 . Even in the presence of high concentration of the salts, the adsorbed enzymes were eluted by urea or by "hydroxy-rich" reagents such as sucrose . 3 . Under the experimental conditions used, the salt concentrations required for elution of the adsorbed enzymes were lower with cellulose than with DEAE-cellulose, CM-cellulose, or P-cellulose, indicating that ion exchange groups, either cationic or anionic, affected the adsorption, although the ion exchange groups of DEAE-cellulose, CM-cellulose, and P-cellulose were weakly but definitely functional as ion exchangers even in the presence of high concentrations of the salts . 4 . The principal attractive force between cellulose and the enzyme was deduced to be due to hydrogen bonding . 5 . This hydrogen bond chromatography was applied for the purification of some yeast enzymes. Eur J Biochem, 1980 Jan, 103(1), 155 - 9 Fluorimetric study of the complex between yeast phenylalanyl-tRNA synthetase and tRNA-Phe . 2 . Evidence for an asymmetric behaviour of the enzyme; Lefevre JF et al.; The variations of several spectroscopic properties of yeast tRNA-Phe and phenylalanyl-tRNA synthetase upon complex formation, were used to study the stoichiometry of the complex in different experimental conditions . In all cases, for the tRNA-Phe-enzyme complex, in the absence of other ligands, the saturations of the different conformational changes monitored for both macromolecules, are achieved at a 2:1 tRNA/enzyme stoichiometry . Phenylalanine does not modify this saturation . In contrast, the presence of 1 mM ATP induces an asymmetric behaviour of the synthetase: two tRNAs are still bound per enzyme molecule but the conformational change of the latter is completed upon binding of a single tRNA molecule. Biochim Biophys Acta, 1980, 595(1), 126 - 32 The site of action of 2,4-dinitrophenol and salicylic acid upon the uncoupler-induced K+ efflux from non-metabolizing yeast; Hoeberichts JA et al.; Stimulation of K+ efflux from non-metabolizing yeast cells by 2,4-dinitrophenol or by salicylic acid occurs only after accumulation of the compounds into the cells, indicating that the site of action of the uncouplers is inside the cells . A correlation is found between the partition ratio of the lipophilic cation dibenzyldimethylammonium between cells and medium and the rate of K+ efflux. J Supramol Struct, 1980, 14(2), 139 - 48 Studies on the biogenesis of an enzymatically active complex III of the respiratory chain from yeast mitochondria; Beattie DS et al.; Complex III isolated from yeast mitochondria catalyzed an antimycin A and Diuron-sensitive coenzyme QH2-cytochrome c reductase activity with a turnover number of 15.7 sec(-1) and contained 10 nmoles of cytochrome b and 4.6 nmoles of cytochrome c1 per mg of protein . Electrophoresis in sodium dodecyl sulfate acrylamide gels resolved Complex III into 10 bands with apparent molecular weights of 50,000, 40,000, 30,000, 29,000, 24,000, 17,000, 16,000, 12,000, 8,400, and 5,800 . Yeast cells were labeled under nongrowing conditions with (35S)-methionine in the absence or presence of inhibitors of cytoplasmic or mitochondrial protein synthesis . Labeled Complex III was isolated by immunoprecipitation from detergent-solubilized mitochondria using anti-serum raised against the purified complex . Analysis of the immunoprecipitates by polyacrylamide gel electrophoresis revealed that a 30,000-dalton protein, cytochrome b, as well as 16,000-dalton protein were labeled in the presence of cycloheximide, indicating that they are products of mitochondrial protein synthesis . Immunoprecipitates from mitochondria obtained from cells labeled in the presence of chloramphenicol contained a new radioactive peak with a molecular weight of 100,000 . In addition, significant decreases in the labeling of the proteins with molecular weights of 50,000, 40,000, 30,000, and 16,000 were observed . When Complex III was isolated by immunoprecipitation from intact spheroplasts after a 5-minute pulse with (35S)-methionine, the 100,000-dalton protein was labeled in the immunoprecipitate whether or not chloramphenicol was present; however, after a 1-hour chase with unlabeled methionine, decreased labeling of the 100,000-dalton protein was observed concomitant with an increased labeling of the 50,000- and 40,000-dalton proteins . These results suggest that a protein with a molecular weight of 100,000 may either be a precursor or a partially assembled form of other proteins of Complex III, most probably the two largest polypeptides. Z Allg Mikrobiol, 1980, 20(6), 389 - 98 Dihydroxyacetone kinase of methanol-assimilating yeast . I . Regulation of dihydroxyacetone kinase from Candida methylica in situ; Hofmann KH et al.; In order to investigate the control behaviour of dihydroxyacetone kinase of methanol-grown Candida methylica under nearly physiological conditions kinetic and regulatory studies were carried out in situ . Yeast cells were made permeable to substrate and reaction products by treatment with Triton X-100 . Normal Michaelis-Menten kinetics resulted in dependence upon the dihydroxyacetone concentration, both at the pH optimum of 7.6 and near the physiological pH-value of 6.5 . The Km obtained for dihydroxyacetone was 0.02 mM, independent of the pH-value . The plots of dihydroxyacetone kinase activity as a function of the ATP concentration revealed complex kinetic characteristics with plateau regions . The maximum reaction rate was reached only after a lag time both at pH 7.6 and concentrations of ATP higher than 5 mM and at pH 6.5 and concentrations of ATP higher than 1.25 mM . Among a great number of tested metabolites no inhibitors of dihydroxyacetone kinase were found . Dihydroxyacetone kinase activity depending upon energy charge according to Atkinson exhibited curves of the U-type . These results and further data concerning the regulation of other enzymes obtained with C . methylica and other yeasts were the basis to propose a preliminary overall model of fine control of the carbon and energy metabolism of methanol-utilizing yeasts. Proc Natl Acad Sci U S A, 1980 Jan, 77(1), 142 - 6 Mitochondrial membrane biogenesis: identification of a precursor to yeast cytochrome c oxidase subunit II, an integral polypeptide; Sevarino KA et al.; Many of the polypeptides made on endogenous ribosomes inside of yeast mitochondria are hydrophobic "integral polypeptides" which are subunits of at least three oligomeric enzyme complexes (cytochrome c oxidase, rutamycin-sensitive ATPase, and coenzyme QH2-cytochrome c reductase) of the inner mitochondrial membrane . In order to elucidate the pathway(s) followed by these polypeptides into the inner membrane we have used an in vitro mitochondrial translation system from yeast . By inhibiting this system with aurintricarboxylic acid, we have been able to demonstrate and accumulate a transient precursor to subunit II of cytochrome c oxidase . This precursor, designated II', is approximately 1,500 daltons larger than mature subunit II and most likely is a form of subunit II with an NH2-terminal extension . Although this precursor appears to be processed cotranslationally under normal conditions, it does associate in unprocessed form with mitochondrial membranes when allowed to accumulate in the presence of aurintricarboxylic acid, and it can be processed postranslationally upon removal of the drug . None of the other mitochondrial translation products made in this system exhibits larger precursors . These results indicate that at least one mitochondrial translation product has a transient "leader sequence" a,d is inserted into the inner mitochondrial membrane and processed cotranslationally, but they suggest that other pathways may be followed by the other translation products. Acta Histochem, 1980, 66(1), 59 - 84 {Ultracryotomy: development and application (with examples from the yeast cytology) (author's transl)}; Bohm KJ; The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis . The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed . Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology . Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts. Biochemistry, 1979 Dec 25, 18(26), 5787 - 91 Isolation and characterization of twenty-three ribosomal proteins from large subunits of yeast; Itoh T et al.; The proteins of large ribosomal subunits from Saccharomyces cerevisiae were separated into 25 fractions by chromatography on columns of carboxymethylcellulose (CMC) . Twenty-three proteins were then purified from the 12 CMC fractions by filtration through Sephadex G-75, Sephadex G-100, and Sephacryl S-200, and/or by phosphocellulose column chromatography . The isolated proteins are YP 1, YP 2, YP 9, YP 11, YP 13', YP 16, YP 18, YP 26, YP 39, YP 41, YP 42, YP 42', YP 44, YP 45, YP 47', YP 52a, YP 53, YP 55, YP 59, YP 62, YP 68, YP A1, and YP A2 . The molecular weight and amino acid composition of these proteins are presented. J Biol Chem, 1979 Dec 25, 254(24), 12461 - 70 Transcription, processing, and mapping of mitochondrial RNA from grande and petite yeast; Morimoto R et al.; Mitochondrial RNA (mtRNA) from petite yeast strains was analyzed by electrophoresis in agarose-urea, acrylamide-urea, and agarose-methyl mercuric hydroxide gels, and by transfer to diazobenzyloxy-methyl paper and hybridization to labeled mitochondrial DNA (mtDNA) . Petites contain numerous mitochondrial transcripts, including processed species like 21 S and 14 S rRNA . Petite transcripts were found to fall into three classes: 1) bands that comigrate with grande mtRNA species; 2) "group-specific" new bands found in multiple strains and coinciding with specific regions of the mitochondrial genome; and 3) "strain-specific" new bands found only in individual petite strains . A deletion map was constructed in which we used the presence or absence of the first two types of mtRNA bands in specific strains, and the restriction endonuclease map of these strains . This map confirmed the localization of 21 S and 14 S rRNA, which were mapped previously by hybridization, and also localized more than 20 additional mtRNA species . The mtRNA species were grouped in regions of the genome in a fashion that strongly suggests that many of them are precursors to fully processed mtRNA species . Hybridization experiments with grande mtRNA and cloned mtDNA fragments have shown the same kind of transcript grouping . Other hybridization experiments have demonstrated two apparent precursors to 21 S rRNA (3700 nucleotides) measuring 5500 and 4500 nucleotides . Processed tRNAs are found only in petites that contain a specific region of the genome near the P (paromomycin resistance) locus . When this region is absent, processed tRNAs are not detected, even for tRNA genes quite distant from the P locus . Since this phenotype is expressed in petites that lack mitochondrial protein synthesis, and since it maps to a specific location in the mitochondrial genome, there appears to be a mtRNA species which has a role in processing of mitochondrial tRNA. J Biol Chem, 1979 Dec 25, 254(24), 12555 - 61 Primary structure of yeast proteinase B inhibitor 2; Maier K et al.; The complete amino acid sequence of yeast proteinase B inhibitor 2 (IB2) was determined to be H3N+-Thr-Lys-Asn-Phe-Ile-Val-Thr-Leu-Lys-Lys-Asn-Thr-Pro-Asp-Val-Glu-Ala-Lys-Lys-Phe-Leu-Asp-Ser-Val-His-His-Ala-Gly-Gly-Ser-Ile-Leu-His-Glu-Phe-Asp-Ile-Ile-Lys-Gly-Tyr-Thr-Ile-Lys-Val-Pro-Asp-Val-Leu-His-Leu-Asn-Lys-Leu-Lys-Glu-Lys-His-Asn-Asp-Val-Ile-Glu-Asn-Val-Glu-Asp-Lys-Glu-Val-His-Thr-Asn-COO- . Elucidation of the primary structure was enabled by automated Edman degradation and COOH-terminal hydrolysis with carboxypeptidases A (bovine pancreas and Y (yeast) . IB2 is the first proteinase inhibitor to be sequenced that possesses a structure devoid of disulfide bridges. J Biol Chem, 1979 Dec 10, 254(23), 12209 - 18 Carbohydrate structure of yeast invertase . Demonstration of a form with only core oligosaccharides and a form with completed polysaccharide chains; Lehle L et al.; Invertase, extracted from broken cells of Saccharomyces cerevisiae X-2180 mm2 mannan mutant, was separated into a fraction insoluble in 75% ammonium sulfate (P75 invertase, 36% carbohydrate) and a soluble fraction (S75 invertase, 53% carbohydrate) . The latter reacted with antibodies specific for the alpha 1 leads to 6-linked mannose of the mannoprotein outer chain, whereas the P75 invertase failed to react with this antiserum although it did react with serum against terminal alpha 1 leads to 3-linked mannose units that are characteristic of the mannoprotein core . A bacterial endo alpha 1 leads to 6-mannanase removed the outer chains from the S75 invertase and converted it to a form that was similar in electrophoretic and immunochemical properties to the P75 invertase, whereas the endomannanase had little effect on the latter invertase . The results suggest that the P75 invertase is a form of the enzyme to which only the core oligosaccharide units had been added, and the S75 invertase represents an enzyme fraction to which the polysaccharide outer chains were also attached . A strong anomeric PMR signal for unsubstituted alpha 1 leads to 6-linked mannose in the S75 invertase, and a much reduced signal in the P75 invertase and endomannanase-digested S75 invertase, support these conclusions . Endo-N-acetyl-beta-glucosaminidase digestion of the S75 and P75 invertases, as well as of a purified wild type yeast invertase, produced an apparently identical series of 3 to 4 carbohydrate-containing proteins that were separable by polyacrylamide gel electrophoresis in sodium dodecyl sulfate but that migrated as a single band on isoelectric focusing . The bands ranged from about 63,000 to 69,000 daltons and differed by the size of one or more carbohydrate core units each of 15 mannoses and 1 N-acetylglucosamine . The results suggest that the external invertase molecules contain some core units without attached outer chains, and that the cells contain a precursor form of the enzyme to which only the core units have been added . In support of this conclusion, PMR spectra and chromatographic patterns show that the core fragments from the P75, S75, and wild type invertases are essentially identical. Cell, 1979 Dec, 18(4), 1261 - 71 Isolation of yeast histone genes H2A and H2B; Hereford L et al.; Analysis of cloned sequences for yeast histone genes H2A and H2B reveals that there are only two copies of this pair of genes within the haploid yeast genome . Within each copy, the genes for H2A and H2B are separated by approximately 700 bp of spacer DNA . The two copies are separated from one another in the yeast genome by a minimum distance of 35-60 kb . Sequence homology between the two copies is restricted to the genes for H2A and H2B; the spacer DNA between the genes is nonhomologous . In both copies, the genes for H2A and H2B are divergently transcribed . In addition, both plasmids code for other nonhistone proteins . Sequences coding for histones H3 and H4 have not been detected in the immediate vicinity of the genes for H2A and H2B. Biochem J, 1979 Dec 1, 183(3), 633 - 46 Kinetic and spectroscopic evidence of cation-induced conformation changes in yeast K+ -activated aldehyde dehydrogenase; Betts GF et al.; The activity, stability and spectroscopic properties of yeast K+ -activated aldehyde dehydrogenase were measured at various times after removal from, and after returning to a solution containing K+ . Enzyme activity is rapidly lost on removal of most of the K+ and rapidly regained if K+ is replaced immediately . These activity changes are slower than likely rates of K+ dissociation and association . These rapid changes in concentration result in altered enzyme stability with enzyme in K+ the more stable . U.v . difference spectra are produced whenever enzyme in an activating environment (K+ or Tl+) is compared with enzyme in a non-activating environment (Tris+ or Li+) . These spectral changes occur within 10s . The saturation characteristics with K+ are hyperbolic for all three phenomena of activation, stabilization and spectral change, with estimated apparent dissociation constants (Ks) for K+ of 7.5 mM, 5.5 mM and 6 mM respectively . Continued incubation of enzyme in the absence of K+ results in the accumulation of an enzyme form that re-activates only slowly on replacing K+ . Stability characteristics in various concentrations of K+ over equivalent time scales are consistent with the existence of additional conformations . Spectroscopic evidence also indicates such additional slow conformation changes . Results have been interpreted in terms of two separate conformation transitions induced or stabilized by K+. Gene, 1979 Dec, 8(1), 121 - 33 Transformation in yeast: development of a hybrid cloning vector and isolation of the CAN1 gene; Broach JR et al.; We have constructed a plasmid, YEp13, which when used in conjunction with transformation in yeast is a suitable vector for isolating specific yeast genes . The plasmid consists of pBR322, the LEU2 gene of yeast, and a DNA fragment containing a yeast origin of replication from 2 mu circule . We have demonstrated the utility of this cloning system by isolating the yeast gene encoding the arginine permease, CAN1, from a pool of random yeast DNA fragments inserted into YEp13. Geburtshilfe Frauenheilkd, 1979 Dec, 39(12), 1017 - 20 {The influence of radium therapie on the yeast contamination of the vagina (author's transl)}; Mendling W et al.; Before the beginning of radium therapy a vaginal yeast contamination of 9,7% was found of 113 patients with different genital carcinomas . However, the incidence of vaginal yeast contamination increased suddenly to 30,9% under the contac irradiation therapy with radium . The radiation effect of radium is not sufficient for a "selfsterilisation" of the radium-carrier in the case of yeast contamination . Therefore, a chemic desinfection of the radium-carriers is principly necessary . The significance of radium therapy with respect to vaginal yeast contamination is discussed and the recommendation is made that routine mycological supervision be carried out on all patients with gynaecological carcinomas and appropriate antimycotic therapy initiated where necessary. Cell, 1979 Dec, 18(4), 1209 - 15 Pleiotropic mutations within two yeast mitochondrial cytochrome genes block mRNA processing; Church GM et al.; The mRNAs from two yeast mitochondrial genes cob-box (cytochrome b) and oxi-3 (cytochrome oxidase 40,000 dalton subunit) are processed from large (7-10 kb) precursors . Certain mutations in each gene block the maturation of the RNAs from both genes at a variety of specific steps . The pleiotropic cytochrome b mutants seem to lack a functional trans-acting RNA required for the processing of both messengers . In contrast, the oxi-3 mutants may act by producing an activity that inhibits specific steps. Carbohydr Res, 1979 Dec, 77, 61 - 70 The synthesis of antigenic determinants for yeast D-mannans and a linear (1to 6)-alpha-D-gluco-D-mannan, and their protein conjugates; Eby R et al.; 2-O-Benzoyl-3,4,6-tri-O-benzyl-1-O-tosyl-D-mannopyranose and 2,3,4-tri-O-benzyl-6-O-(N-phenylcarbamoyl)-1-O-tosyl-D-glucopyranose were allowed to react with partially blocked 2-{4-(ptoluensulfonamido)phenyl}ethyl alpha-D-manno- and gluco-pyranosides . Disaccharides having alpha-D-Manp-(1 to 2)-alpha-D-Manp, alpha-D-Manp-(1 to 6)-alpha-D-Glcp, alpha-D-Manp-(1 to 6)-alpha-D-Manp, and alpha-D-Glcp-(1 to 6)-alpha-D-Manp structures, and a branched trisaccharide having the structure alpha-D-Manp-(1 to 2)-{alpha-D-Manp-(1 to 6)}-alpha-D-Manp were synthesized . The oligosaccharid:s were deblocked with sodium in liquid ammonia to give glycopyranosides having a free primary aromatic amine which were converted into isothiocyanate derivatives with thio-phosgene . The functionalized oligosaccharides were then coupled to bovine serum albumin to give protein conjugates. Proc Natl Acad Sci U S A, 1979 Dec, 76(12), 6096 - 100 13C nuclear magnetic resonance studies of anaerobic glycolysis in suspensions of yeast cells; den Hollander JA et al.; Anaerobic glycolysis in Saccharomyces cerevisiae has been studied by 13C NMR at 90.5 MHz . {1-13c}Glucose and {6-13C}glucose were fed to suspensions of yeast cells . Time courses for concentration changes of the starting material, of courses for concentration changes of the starting material, of the intermediate fructose 1,6-bisphosphate (Fru-P2), and of the end products, ethanol and glycerol, have been followed with 1-min time resolution . The glucose uptake was well fitted by a Michaelis-Menten model, assuming competition of alpha- and beta-glucose for the same site . The Km for the uptake was found to be 10 mM for beta-glucose and 5 mM for alpha-glucose . The concentration of Fru-P2 showed an initial oscillation before it reached a co,stant level . The 13C label, introduced only as {-13C}- or {6-13C}glucose, was observed in Fru-P2 in both the C1 and C6 positions, simultaneously . From the relative intensities of the C1 Fru-P2 and C6 Fru-P2 peaks in the presence of {1-13C}- and {6-13C}glucose, in vivo kinetic information was obtained about the aldolase-triosephosphate isomerase triangle . We found that under the conditions of these experiments the ratios of backward to forward velocities through aldolase and triosephosphate isomerase were 0.9 +/- 0.1 and 0.8 +/- 1, respectively, indicating they were close to equilibrium. Biochemistry, 1979 Nov 27, 18(24), 5489 - 95 Direct iodination of specific residues in crystals of yeast formylatable methionine-accepting transfer ribonucleic acid; Tropp J et al.; Crystals of yeast formylatable methionine-accepting transfer ribonucleic acid (tRNAfMet) were iodinated by using a modification of Commerford's procedure {Commerford, S.L . (1971) Biochemistry 10, 1993} . Chromatographic analysis of nuclease digestion products showed that radioactive iodine binds covalently to the 5 position of three nucleotide residues: U8, C73, and C74 . These three iodine substitutions were assigned to three peaks in a difference Fourier synthesis comparing the iodinated derivative with native tRNAfMet . In this way the positions of U8, C73, and C74 were marked in the crystal structure of yeast tRNAfMet, providing guidepoints for the interpretation of a 4.5-A electron density map. J Biol Chem, 1979 Nov 25, 254(22), 11735 - 40 Sequence analysis of two yeast mitochondrial DNA fragments containing the genes for tRNA Ser UCR and tRNA Phe UUY; Miller DL et al.; Two restriction enzyme fragments containing yeast mitochondrial tRNA genes have been characterized by DNA sequence analysis . One of these fragments is 320 base pairs long and contains a tRNA Ser gene . The corresponding tRNA SER was isolated from yeast mitochondria and its nucleotide sequence also was determined . This mitochondrial tRNA is 90 nucleotides in length, has a G + C content of 38%, and has UGA as the anticodon . A portion of a 680-base-pair DNA fragment containing a tRNA Phe gene was also sequenced . The portion of this gene which codes for the mature tRNA is 75 base pairs in length, has a G + C content of 33%, and contains the anticodon GAA . Neither gene contains an intervening sequence or codes for the 3' CCA terminus . Both are surrounded by regions of more than 90% A + T . The significance of these sequences is discussed. J Biol Chem, 1979 Nov 25, 254(22), 11323 - 9 Substrate binding closes the cleft between the domains of yeast phosphoglycerate kinase; Pickover CA et al.; Using small angle x-ray scattering from solutions of yeast phosphoglycerate kinase, we have measured the radius of gyration of the enzyme both in the presence and in the abscence of ligands . We find that the radius of gyration decreases by 1.09 +/- 0.34 A upon binding both substrates MgATP and 3-phosphoglycerate to form the ternary complex . Smaller decreases, at the limit of the precision of the measurement, were found for the separate binding of MgATP (0.30 +/- 0.50 A) . Using computer modeling, it has been estimated that a substrate-induced cleft closure in phosphoglycerate kinase resulting from one lobe rotating 8-14 degrees relative to the other lobe lobe is consistent with this observed change in radius of gyration . We suggest, therefore, that the conformational change that results in the smaller radius of gyration for the ternary complex is a hinge motion of the two lobes which produces a closing of the cleft between the two lobes . The apparent similarity of the ligand-induced change in phosphoglycerate kinase to the cleft closure in hexokinase suggests that this kind of conformational change may prove to be a rather general kinase phenomenon (Bennett, W.S., and Steitz T.A . (1978) Proc . Natl . Acad . Sci . U.S.A . 75, 4848-4852; Anderson, C.M., Zucker, F.H., and Steitz, T.A . (1979) Science 204, 375-380). Biochim Biophys Acta, 1979 Nov 23, 581(1), 1 - 14 Resonance Raman study on yeast cytochrome c peroxidase . Effect of coordination and axial ligands; Sievers G et al.; Resonance Raman spectra are reported for native ferric cytochrome c peroxidase, its cyanide and fluoride compounds, those of the ferrous enzyme and its cyanide and carbonyl compounds, and the spectrum of the hydrogen peroxide compound, compound I . Band frequencies of ferric horseradish peroxidase isoenzyme C2 and its derivatives are also given . Comparison of the frequencies of the bands around 1400, 1500, 1560-1580, and 1610-1640 cm-1 with those of other hemoproteins and heme model compounds showed that in ferric highspin compounds in particular the bands are not only spin and oxidation sensitive, as has previously been reported, but that they also reflect the coordination of the heme iron . It is suggested that ferric cytochrome c peroxidase and horseradish peroxidase are pentacoordinated . In the hexacoordinated fluoride, cyanide and carbon monoxide derivatives the bands reflect the spin state and the out-of-plane position of the heme iron . The spectrum of cytochrome c peroxidase compound I supports previous studies that suggest that it has a lowspin heme iron in the Fe(IV) oxidation state. Biochim Biophys Acta, 1979 Nov 22, 565(1), 173 - 82 A ribonuclease from yeast associated with the 40 S ribosomal subunit; Schulz-Harder B et al.; 1 . Autodegradation of yeast ribosomes is due to a 'latent' ribonuclease which is associated with the 40 S ribosomal subunit . 2 . The ribonuclease was extracted in the presence of EDTA from ribosomes and purified 118-rold by protamine sulphate precipitation, (NH4)2SO4 fractionation and chromatography on DEAE-cellulose . 3 . The optimum pH for this enzyme is 5 to 6.5 while the optimum temperature is 45 to 50 degrees C . Incubation for 10 min at 60 degrees C caused a reduction in enzyme activity of 70% . 4 . The ribonuclease has an endonucleolytic activity against rRNA, tRNA, poly(A), poly(U) and poly(C) but does not degrade poly(G) or DNA . It hydrolyzes the homopolymers to nucleoside 3'-phosphates . 5 . Zn2+, Mn2+, heparin, glutathione and p-chloromercuribenzoate inhibit the ribonuclease, while Na+, K+, EDTA and sermidine have only little or no effect . 6 . It binds tightly to yeast ribosomes but only loosely to ribonuclease-free wheat germ ribosomes . 7 . Polyribosomes possess less autodegradation activity than monoribosomes, isolated from the same homogenate. J Biol Chem, 1979 Nov 10, 254(21), 10920 - 4 Identification of two different RNase H activities associated with yeast RNA polymerase A; Iborra F et al.; Two ribonuclease H activities have been found in yeast RNA polymerase A . The nuclease activities comigrated with subunits A49 (Mr = 49,000) and A40 (Mr = 40,000), after electrophoresis in a sodium dodecyl sulfate polyacrylamide gel containing {32P}(rG)n . (dC)n as substrate . Both activities were also found, among other nucleases, in a high salt chromatin extract . Several lines of evidence suggest that the chromatin RNase H of 49,000 daltons (RNase H49) is the same protein as subunit A49 . They co-migrate on sodium dodecyl sulfate-gel electrophoresis, have the same chromatographic properties, and dissociate simultaneously from RNA polymerase A . Fractions containing RNase H49 stimulate RNA synthesis by RNA polymerase A* lacking A49 and A34.5 subunits . Finally, limited proteolysis of the protein band having RNase H49 activity yields the characteristic fingerprint of the A49 subunit . This subunit, therefore, exists in two states: bound to chromatin and associated with RNA polymerase A . On the other hand, it is not yet clear whether the RNase H activity of 40,000 daltons, associated with RNA polymerase A, is due to the A40 subunit or whether it represents a trace contamination by a very active nuclease tightly bound to the enzyme. Poult Sci, 1979 Nov, 58(6), 1548 - 56 Reduction of hepatic lipid deposition in laying hens by dietary selenium-yeast interaction; Maurice DV et al.; Experiments were conducted to study the effect of chromiun and selenium on liver lipid deposition and incidence of liver hemorrhage in caged layers . Commercial strains of layers were fed ad libitum equicaloric and isonitrogenous diets . Corn-torula dried yeast diets containing added selenium (.1 microgram/g) with or without supplementary chromium (10 microgram/g) significantly reduced total liver lipid and liver hemorrhage . The effects of protein source (soybean meal vs . yeast) and selenium were separated in a factorial experiment which showed that the hepatic lipid response to selenium results from an interaction of selenium with an unidentified factor in torula yeast . The addition of selenium to diets with each protein source significantly elevated glutathione peroxidase (GSHPx) activity . Inclusion of 5% brewers yeast in the corn-soy diet or vitamin E (50 IU/kg) to the corn-torula dried yeast reduced liver lipid similar to that seen in birds fed the torula-yeast diet containing .1 microgram Se/g . Comparison of oral glucose tolerance of birds fed corn-soy and corn-soy brewers yeast diets showed no significant difference . None of the dietary treatments significantly altered body weight, egg production, egg weight, or feed consumption . The results indicate that the metabolic role of selenium in relation to its role in hepatic lipid metabolism is mediated through an interaction with a dietary factor(s) present in yeast. Int J Radiat Biol Relat Stud Phys Chem Med, 1979 Nov, 36(5), 479 - 88 Modification of high LET radiation-induced damage and its repair in yeast by hypoxia; Subrahmanyam P et al.; The lethal response of a diploid yeast strain BZ34 to densely ionizing radiations from the reaction 10B(n, alpha)7 Li was studied . The values for relative biological effectiveness (r.b.e.) and oxygen enhancement ratio (o.e.r.) for this radiation compare favourably with the data obtained with charged particles on the same strain of yeast . Recovery from potentially lethal damage was also studied by post-irradiation holding under non-nutrient conditions . In order to understand the role of oxygen in the recovery process, the investigation covered the following treatment regimens: (a) aerobic irradiation and aerobic holding (A-A), (b) aerobic irradiation and hypoxic holding (A-H), (c) hypoxic irradiation and hypoxic holding (H-H) and (d) hypoxic irradiation and aerobic holding (H-A) . It has been found that the presence of oxygen is essential for recovery from the damage induced by both gamma rays and high linear energy transfer (LET) radiations . The extent of recovery was larger for gamma-induced damage than for damage induced by high LET radiation (alpha + 7Li) for the A-A condition . In the H-H condition, while only a slight recovery was seen for gamma-induced damage, it was totally absent for high LET damage . For the modality A-H, it was found that there is not recovery from the sparsely ionising gamma radiation-induced damage . The implications of these results for the treatment of malignant tumours by radiotherapy are briefly discussed. J Gen Microbiol, 1979 Nov, 115(1), 13 - 8 Mercury-induced loss of K+ from yeast cells investigated by electron probe x-ray microanalysis; Kuypers GA et al.; According to Passow & Rothstein (1960), the mercury-induced loss of K+ from yeast cells is an all-or-none effect . This hypothesis was tested by analysing individual yeast cells by means of energy-dispersive X-ray microanalysis . A dual effect of mercury was observed . The cell population was split into two parts: one part consisted of cells that had suffered a (nearly) complete loss of K+- the number of these cells increased with increasing concentrations of HgCl2; the other consisted of cells that had only lost part of their K+ content--these cells showed a normal distribution around a central value that decreased with increasing concentrations of HgCl2 . Our analysis shows that the effect of mercury is more complex than originally suggested and that, in addition to an all-or-none effect, a gradual loss of K+ occurs. Carbohydr Res, 1979 Nov, 76, 225 - 32 The substrate specificity of yeast hexokinase: reaction with D-arabinose oxime; Finch P et al.; By chromatography, electrophoresis, n.m.r . spectroscopy, and spectrophotometric assay, it has been shown that D-arabinose oxime acts as a weak substrate for yeast hexokinase . The enzyme-catalysed phosphorylation of the oxime, which exists as a mixture of E (80%) and Z (20%) acyclic forms in solution at equilibrium, is proposed to proceed via the transient formation of a furanoid species . Weak substrate-activity was also observed with 4-deoxy-D-xylo-hexose, but not with 5-deoxy-D-xylohexose . The relation of these and previous results concerning the carbohydrate-substrate specificity of yeast hexokinase in solution to X-ray crystallographic studies is discussed. J Biochem (Tokyo), 1979 Nov, 86(5), 1487 - 94 Equilibrium and kinetics of the thermal unfolding of yeast 5S ribosomal RNA; Maruyama S et al.; The equilibrium and kinetics of thermal unfolding of yeast 5S ribosomal RNA have been studied by optical methods, in a low ionic strength environment without Mg2+, to follow the disruption of the secondary structure base pairs in the molecule . The equilibrium results demonstrated that all of the helical regions melted simultaneously, and the kinetics of the thermal unfolding were first order . These findings suggest the validity of the two-state approximation for the unfolding reaction under the present conditions . The total number of secondary structure base pairs estimated from our experiment was consistent with that contained in the conformational model based on the Raman spectrum rather than that in the one derived by the enzymic digestion method . Taking our results on the kinetic behavior of the thermal unfolding overall, we propose that the 5S RNA has a partly melted secondary structure under the solvent conditions used. Eur J Biochem, 1979 Nov, 101(2), 607 - 17 The identification of apocytochrome b as a mitochondrial gene product and immunological evidence for altered apocytochrome b in yeast strains having mutations in the COB region of mitochondrial DNA; Kreike J et al.; The yeast mitochondrial translation product of Mr 30 000 is identical with apocytochrome b . After labelling in vivo with {35S}sulphate in the presence of cycloheximide, the radioactivity in this product present in solubilized submitochondrial particles, was completely recovered in pure cytochrome bc1 complex as a single polypeptide . We show that this translation product is identical with apocytochrome b using peptide mapping by limited proteolysis according to Cleveland et al . {J . Biol . Chem . 250 (1977) 8236-8242} and by immunoprecipitation with a specific antiserum against apocytochrome b . New mitochondrial translation products in 36 strains of Saccharomyces cerevisiae having mutations in the COB region of the mitochondrial DNA, are precipitated by this antiserum . This is consistent with the assumption that many of the cob mutations are localized in the structural gene for apolcytochrome b on mitochondrial DNA . Mutations in two intervening sequences can give rise to products related to apocytochrome b that are considerably longer than normal apocytochrome b . We discuss the hypothesis that in these mutants splicing of the messenger RNA does not occur correctly and that, as a consequence of this, ribosomes read through in an intervening sequence. Eur J Biochem, 1979 Nov, 101(2), 413 - 22 Identity of malonyl and palmitoyl transferase of fatty acid synthetase from yeast . 2 . A comparison of active-site peptides; Engeser H et al.; Active-site peptides of malonyl and palmitoyl transferase from yeast fatty acid synthetase were isolated and sequenced to try to prove the hypothesis {J . Ayling, R . Pirson & F . Lynen (1979) Biochemistry 11, 526--533} that both enzymes are identical . For this purpose synthetase modified with 5,5'-dithiobis(2-nitrobenzoic acid) was labelled with either {14C}malonyl or {14C}palmitoyl residues followed by proteolytic digestion of the labelled protein . {14C}Malonyl-peptides were isolated by conventional purification procedures; their structures were determined by a combination of methods . {14C}Palmitoyl-peptide material was purified by high-performance liquid chromatography and the structure determined by solid-phase Edman degradation and other analytical methods . Serine was identified as the acyl acceptor group in both transferases . Comparison of the sequence data available shows that the sequence around the acyl acceptor group in both cases is identical . This proves the identity of malonyl and palmitoyl transferase. Eur J Biochem, 1979 Nov, 101(2), 407 - 12 Identity of malonyl and palmitoyl transferase of fatty acid synthetase from yeast . Functional interrelationships between the acyl transferases; Engeser H et al.; Functional interrelationships between the acyl transferases of yeast fatty acid synthetase were investigated . In binding assays with synthetase modified by 5,5'-dithiobis(2-nitrobenzoic acid), 4--5 malonyl transferase entities per multienzyme complex molecule could be titrated . In the presence of palmitoyl-CoA these malonyl transferases were found inaccessible to malonyl-CoA, whereas the acetyl transferases were reactive towards acetyl-CoA . Between four and five palmitoyl transferase entities per synthetase equivalent were found reactive towards palmitoyl-CoA, the palmitoyl binding being inhibited by malonyl-CoA . Following palmitoyl binding the acetyl transferases were found towards acetyl-CoA . Substrate model assays were consistent with these data . It is concluded that malonyl and palmitoyl transferases are closely coupled enzyme components of the multienzyme complex which are fairly independent of the acetyl transferase entities . The molecular basis for the observed coupling will be given in the following paper. J Inorg Biochem, 1979 Nov, 11(3), 279 - 82 Specific heavy metal labeling of the 3-'terminus of phosphorothioate modified yeast tRNAPhe; Szalda DJ et al.; Yeast tRNAPhe containing a phosphorothioate modified -CS-CS-A terminus binds two moles of chloroterpyridineplatinum(II) . This result was determined by titrating the tRNA with {3H}(terpy)PtCl} Cl, removing excess platinum by cation exchange chromatography, and determining the amount of bound platinum by radiocounting techniques . It has thus been established that adjacent phosphorothioate modified nucleotides can be labeled with an electron dense stain, a necessary requirement for electronmicroscopic sequencing of polynucleotides to become practical. Nature, 1979 Nov 1, 282(5734), 39 - 43 Isolation and characterisation of a yeast chromosomal replicator; Stinchcomb DT et al.; A yeast DNA sequence that behaves as a chromosomal replicator, ars1 (autonomously replicating sequence), has been isolated . On transformation, ars1 allows autonomous replication of all co-linear DNA . The replicator can integrate into other replication units and can function in multimeric form . The 850-base pair ars1 element has no detectable homology to other yeast sequences . Such replicator-containing plasmids can be used for the isolation of DNA sequences in yeast cells as well as for the study of chromosomal DNA replication. J Virol, 1979 Nov, 32(2), 692 - 6 Evolution of defective-interfering double-stranded RNAs of the yeast killer virus; Kane WP et al.; We have characterized by T1 fingerprint analysis several defective interfering (DI) double-stranded RNAs of the simple yeast virus ScV . A common sequence of about 0.5 to 0.6 kilobase pairs, including both 3' termini of the parental RNA, was present in each DI RNA . Several DI RNAs had novel T1 oligonucleotides not present in their parental RNA. J Bacteriol, 1979 Nov, 140(2), 649 - 54 Polyamine biosynthesis during germination of yeast ascospores; Brawley JV et al.; The role of the diamine putrescine during germination and outgrowth of ascospores of Saccharomyces cerevisiae was examined . Ornithine decarboxylase activity increased and declined rapidly during germination and outgrowth; peak activity was attained after the cells had proceeded through the G1 interval of the cell cycle, whereas minimal activity was present at the completion of the first cell division . alpha-Methylornithine inhibited both ornithine decarboxylase activity and the in vivo accumulation of putrescine . In the presence of alpha-methylornithireak dormancy and proceed through one cell division . Subsequent cellular growth, however, was retarded but not completely inhibited . The supplementation of Methylglyoxal bis(guanylhydrazone) to sporulation medium greatly inhibited this sexual process . These data suggest that the synthesis of putrescine is not required for the breaking of spore dormancy, but that polyamine biosynthesis may be essential for meiosis and sporulation. Prikl Biokhim Mikrobiol, 1979 Nov-Dec, 15(6), 805 - 10 {Paraffin oxidizing system of the yeast Candida guilliermondii}; Ol'sinskaia NL et al.; It has been demonstrated that the enzyme system of Candida guilliermondii responsible for hydrocarbon oxidation involves NADPH-cytochrome c-reductase (EC 1623) and cytochrome P-450 . The system is located in the microsomal fraction . Cytochrome P-450 synthesis is induced by hexadecane occurring in the medium . The cellular content of cytochrome P-450 varies in the course of the culture growth . There is a correlation between the cellular content of cytochrome P-450 and the synthesis of primary products of hexadecane oxidation. J Biol Chem, 1979 Oct 25, 254(20), 10051 - 60 Biosynthesis of yeast glycoproteins . Processing of the oligosaccharides transferred from dolichol derivatives; Parodi AJ; The oligosaccharides previously bound to dolichol diphosphate were isolated from Saccharomyces cerevisiae cells incubated with {U-14C}glucose . Five compounds were obtained that migrated with RGlucose of 0.100, 0.120, 0.145, 0.180, and 0.215 on paper chromatography . All of them contained mannose and 2 N-acetylhexosamine residues . The substances that migrated with the three lower RGlucose values had, in addition, glucose units . The structure of the oligosacchardies was very similar if not identical with that of the oligosaccharides isolated from the dolichol diphosphate derivatives synthesized "in vitro" by yeast or rat liver particulate preparations or "in vivo" by dog thyroid or rat liver slices as judged by their migration on paper chromatography, monosaccharide composition, and degradation compounds produced by alpha-mannosidase treatment or acetolysis . The oligosaccharides previously bound to asparagine residues in proteins were isolated from yeast cells which had been pulsed with {U-14C}glucose and chased with medium containing the unlabeled monosaccharide . The samples taken after very short pulses contained four oligosaccharides that migrated with RGlucose of 0.100, 0.120, 0.145, and 0.180 on paper chromatography . The first three compounds contained glucose, mannose, and 2 N-acetylhexosamine residues whereas the one that migrated with a RGlucose of 0.180 was devoid of the former monosaccharide . Samples taken after short chase periods revealed that the compounds that migrated with the lower RGlucose values gradually disappeared and were converted to the oligosaccharide with the higher RGlucose value was they lost their glucose residues . Similar analysis as those mentioned above showed that the structures of these compounds were similar to those of the dolichol diphosphate-bound oligosaccharides . Samples taken after longer chase periods revealed that the oligosaccharide that migrated with a RGlucose of 0.180 was subsequently either enlarged by the addition of more mannose residues or trimmed to smaller sizes. Biochim Biophys Acta, 1979 Oct 24, 580(2), 339 - 55 Characterization of a yeast phase specific protein from a fungus, Histoplasma capsulatum; Stetler DA et al.; We have characterized an unusual yeast phase specific protein from Histoplasma capsulatum . The protein, which we have called protein 6, is produced by the yeast cells which have been derepressed for sulfite reductase, and it can account for more than 40% of the total extract protein . Synthesis of both sulfite reductase and protein 6 is subject to cysteine repression . However, sulfite reductase activity is maximal in logarithmically growing cells whereas protein 6 is synthesized de novo and accumulated by stationary phase cells . The following are the major physicochemical properties of protein 6: (1) the native protein has a molecular weight of about 15 000; (2) electrophoresis on a sodium dodecyl sulfate polyacrylamide gel yielded a single band with a molecular weight 7600; (3) protein 6 is capable of reducing the dye, nitroblue tetrazolium, and cytochrome c, a property that has been found to be shared by a number of trypsin inhibitors, and (4) the molecule is negatively charge and is relatively resistant to proteolysis . The amino acid composition of protein 6 has been determined. Biochemistry, 1979 Oct 16, 18(21), 4588 - 99 On the structure and conformational dynamics of yeast phenylalanine-accepting transfer ribonucleic acid in solution; Ehrenberg M et al.; The solution structure of yeast tRNAPhe was investigated by using ethidium as a fluorescent probe in the D loop and the anticodon loop . For this purpose the dihydrouracils in position 16/17 and wybutine in position 37 were substituted by ethidium . The lifetimes and the time-dependent anisotropy of ethidium fluorescence were measured by pulsed nanosecond fluorometry . The kinetics of the transitions between different states of the tRNAPheEtd derivatives were determined by chemical relaxation measurements . It was found that the ethidium label irrespective of its position exhibits three different states called T1, T2 and T3 characterized by lifetimes tau 1 = 30 ns, tau 2 = 12 ns, and tau 3 = 3 ns . The lifetime differences are due to different accessibilities of ethidium for solvent quenching in the three states . Thus, there are three different defined structural environments of the ethidium in both the anticodon and the D loop . The distribution of the three states was measured as a function of Mg2+ concentration and temperature; it was found that state T3 is favored over states T2 and T1 by both increasing Mg2+ concentration and increasing temperature . The chemical relaxation kinetics exhibit a fast transition between T1 and T2 (10--100 ms) and a slow transition between T2 and T3 (100--1000 ms) . The rates of both transitions depend likewise on Mg2+ concentration and temperature . The equilibrium and kinetic data clearly show the presence of strong and weak interactions between Mg2+ and tRNA . A cooperative model accounting for this behavior is developed . The ethidium probe behaves identically when located in different regions of the tRNA regarding both its distribution of states and its transition kinetics . This suggests that the different spectroscopic states report different conformations of the tRNA structure . The dependence of the three states on Mg2+ and spermine indicates that conformation T3 is closely related to or identical with the crystal structure . The rotational diffusion constants indicate that of all three states T3 is most extended while T2 is most compact . The thermodynamic analysis reveals that the strongly bound Mg2+ ions reduce both the activation entropy and enthalpy of all transitions . The weakly bound Mg2+ ions increase both the activation enthalpy and entropy of the slow transition between T2 and T3 . It is suggested that the breaking of several intramolecular bonds, e.g., hydrogen bonds, is involved in this transition. Eur J Biochem, 1979 Oct 15, 100(2), 359 - 64 Influence of coenzyme on the refolding and reassociation in vitro of glyceraldehyde-3-phosphate dehydrogenase from yeast; Krebs H et al.; Kinetic analysis of the reactivation in vitro of glyceraldehyde-3-phosphate dehydrogenase from yeast in the presence of NAD+ suggested that transconformation reactions of inactive monomers and their subsequent association to native tetramers are responsible for the sigmoidal relaxations {R . Rudolph et al . (1977) Eur . J . Biochem . 81, 563-570} . Comparison with the reactivation behaviour in the absence of coenzyme was not feasible at this stage due to the instability of the apoenzyme . In the present study, solvent conditions were established which allowed both apoenzyme and holoenzyme to exhibit high stability . The apoenzyme is stable in phosphate buffer; but if excess NAD+ and phosphate are present (both of which stabilize the enzyme if applied separately), destabilization occurs . Protection of functional groups against oxidation by addition of a reducing agent and by degassing and preventing contact with air, increase the stability . Only partial stabilization can be achieved in the presence of NADH . Comparing the kinetics of reactivation in the presence and absence of coenzymes shows that both oxidized and reduced coenzyme enhance the rate of reactivation significantly, and to the same extent . The kinetic effect of coenzyme binding to the refolding polypeptide chain is discussed in terms of the stabilization of intermediates or end products of reconstitution on the one hand, and acceleration of folding and association reactions, on the other. J Biol Chem, 1979 Oct 10, 254(19), 9331 - 4 Mutations in putative intervening sequences of the mitochondrial cytochrome b gene of yeast produce abnormal cytochrome b polypeptides; Solioz M et al.; The apoprotein of yeast cytochrome b is translated on mitochondrial ribosomes and coded for by a split gene which is located in the COB-BOX region on mitochondrial DNA . With the aid of an antibody against cytochrome b, we identified the cytochrome b-cross-reacting polypeptides of respiration-deficient mutants mapping either in coding or intervening sequences of the cytochrome b gene . Most mutations in the coding regions caused the accumulation of a single apocytochrome b fragment whose apparent molecular weight (12,000 to 26,600) depended on the map position of the mutation . In contrast, mutations in putative intervening sequences often led to multiple new polypeptides immunologically related to apocytochrome b . Some of these abnormal polypeptides were considerably larger than wild type apocytochrome b . This suggests that mutations in intervening sequences can thus generate aberrant polypeptide products. Mol Gen Genet, 1979 Oct 3, 176(2), 255 - 64 Genetics of oxidative phosphorylation: mitochondrial loci determining ossamycin-, venturicidin- and oligomycin-resistance in yeast; Lancashire WE et al.; With a view towards identifying new ATPase loci on the mitochondrial genome a large number of oligomycin-, ossamycin- and venturicidin-resistant mutants were isolated after MnCl2 mutagenesis . The mutants were subjected to mass-screens which divided them into different cross-resistance phenotype-classes and also distinguished the common OLI1 mutations from the mutations at all other loci . Allelism tests between examples of the different classes of phenotype indicated that the majority of mutations in the population mapped at the previously known loci OLI1, OLI2, OLI3, and OLI4 . Mutations conferring specific ossamycin resistance defined two new loci, namely OSS1 and OSS2 which are linked to the OLI2 and OLI1 loci respectively . A few rare mutations comprise a new locus OLI5 which is linked to the OLI1 locus (12.6% total recombination) . In conclusion we can now say that that there are two unlinked segments of the mitochondrial genome, each of which is composed of several distinct, genetically-linked loci . One segment contains the OLI1, OLI3, OLI5 and OSS2 loci and the other the OLI2, OLI4 and OSS1 loci . The phenotypically-distinguishable mutations described herein should facilitate fine-structure mapping of these two segments. Mol Gen Genet, 1979 Oct 3, 176(2), 297 - 300 NADP-specific glutamate dehydrogenase is not involved in repression of yeast sporulation by ammonia; Newlon MC; In Saccharomyces cerevisiae, the presence or absence of NADP-specific glutamate dehydrogenase does not affect inhibition of sporulation by ammonia, suggesting that the inhibition is not mediated by this enzyme. Mol Gen Genet, 1979 Oct 2, 176(1), 41 - 52 Formation and fate of cross-links induced by polyfunctional anticancer drugs in yeast; Fleer R et al.; A method to detect low levels of interstrand cross-links in DNA of Saccharomyces cerevisiae is described . Isopycnic ultracentrifugation of alkali-treated, unpurified Eaton press homogenates allows the detection of less than one cross-link per yeast chromosome . Efficient separation of single- and double-stranded DNA requires low cell density and addition of glycerol during homogenization . Using a yeast strain defective in excision repair, a dose dependent formation of interstrand cross-links after treatment of cells with biological doses of nitrogen mustard, Triaziquone and Chloramubil could be demonstrated . The most powerful of these alkylating agents is Triziquone: half of the DNA molecules are shown to be cross-linked after a 12 min exposure to 9 X 10(-9) g/ml of the drug . The cross-linking reaction continues after excessive alkylating agent is removed . After having reached a maximum the fraction of renaturable DNA decreases upon further incubation . The speed of this "after-reaction" depends on temperature: 48 h after the end of treatment renaturability of DNA has almost completely disappeared when cells are kept at 36 degrees C. Chromosoma, 1979 Oct 2, 75(1), 101 - 15 Morphogenesis of the synapton during yeast meiosis; Horesh O et al.; The formation of the synapton (synaptonemal complex) was followed by an electron microscopic examination of large samples of Saccharomyces cerevisiae cells at various stages of meiosis . Three temperature-sensitive mutants were used, cdc4, cdc5 and cdc7, which undergo a slow but normal meiosis at 25 degrees C . At the restrictive temperature of 34 degrees C, cdc4 and cdc5 arrest at an advanced enough stage of meiosis to allow the study of synapton morphogenesis . Based on the frequencies of nuclear structures, we describe the formation of the central region and central elements of the synapton in the dense body, which may be part of the nucleolus . This process occurs during early meiotic stages, concomittantly with recombination commitment and premeiotic DNA replication . Mature synaptons usually appear after premeiotic S, at the pachytene stage, and later disappear . A possible intermediate stage in this disappearance is found in arrested cdc5 cells, which contain paired lateral elements without central elements . Following the frequencies of spindle plaque configurations, we conclude that the plaques in meiosis duplicate once at the beginning of the main DNA replication, as is also observed prior to mitosis . In contrast to mitotic cells, however, meiotic plaques remain duplicated for a long period, until the synaptons disappear, and only then separate from each other to form a spindle . During late stages of the first meiotic division, the outer plates of the spindle plaques thicken, to duplicate later and give the second division spindles . The characteristically thick outer plate may have a role in the formations of the ascopore wall. Gann, 1979 Oct, 70(5), 687 - 92 Effect of immunochemotherapy with OK-432 and yeast cell wall on the activities of peritoneal macrophages of mice; Mashiba H et al.; The effect of chemotherapy combined with immunostimulants on the activities of macrophages in mice was studied . The number of macrophages and exudate cells in the peritoneal cavity increased 3 days after ip injection with mitomycin-C, cyclophosphamide, and 5-fluorouracil together with OK-432 or yeast cell wall and decreased to normal level after 9 days, while the number of the cells remained decreased in mice receiving multi-drugs alone . Acid phosphatase activity of the macrophages of mice was elevated after the simultaneous injection of yeast cell wall and OK-432, and high activity was preserved in the macrophages of mice receiving yeast cell wall even after 9 days . Spreading of these cells was also enhanced . Macrophage activities examined by these assays were maximal in every respect 6 days after combination therapy . Cytostatic activity of the cells was strengthened after 6 days by combined use of OK-432 or yeast cell wall . Role of the activated macrophages in combination therapy was discussed. Int J Radiat Biol Relat Stud Phys Chem Med, 1979 Oct, 36(4), 317 - 24 Reparable and irreparable damage in yeast cells induced by sparsely ionizing radiation; Frankenberg D; It is shown that in diploid yeast there are significant differences in the extent of irreparable damage after irradiation with X-rays, 60Co-gamma-rays and 30 MeV electrons . At extremely low dose rates, 60Co-gamma-rays were found to produce almost no irreparable damage at least up to 1200 Gy . X-rays, however, at the same low dose rate caused irreparable damage in the same dose range yielding a surviving fraction of 0.25 at 1200 Gy . For irradiations at high dose rate followed by liquid holding recovery the relative biological effectiveness of X-rays amounted to at least 4 for absorbed doses of up to 1000 Gy . With 30 MeV electrons at high dose rates an accumulation of sublethal and potentially lethal damage resulting in irreparable damage occurred above 1000 Gy . It is suggested that irreparable damage in yeast is due to a cooperative effect of neighbouring track ends. Genetics, 1979 Oct, 93(2), 375 - 81 Genetic analysis of gamma-ray mutagenesis in yeast . II . Allele-specific control of mutagenesis; McKee RH et al.; We find that partially different sets of gene functions are required for the production of different kinds of mutations induced by 60Co gamma rays in Saccharomyces cerevisiae . This observation is very similar to others made previously with respect to UV mutagenesis (LAWRENCE and CHRISTENSEN 1978a,b, 1979) and confirms the conclusion that such distinctive patterns of genetic control reflect properties of the test alleles and their genetic locations, rather than the kinds of lesions required to revert them . The data also support the model of mutagenic repair outlined in the first paper of this series (McKee and LAWRENCE 1979), in which partially different sets of gene functions are required for the production of different kinds of mutations, the formation of mutations at different genetic sites and the induction of mutations by different mutagens. Genetics, 1979 Oct, 93(2), 361 - 73 Genetic analysis of gamma-ray mutagenesis in yeast . I . Reversion in radiation-sensitive strains; McKee RH et al.; The frequency of revertants induced by 60Co gamma rays of the ochre allele, cyc1-9, has been measured in radiation-sensitive strains carrying one of 19 nonallelic mutations and in wild-type strains . The results indicate that ionizing radiation mutagenesis depends on the activity of the RAD6 group of genes and that the gene functions employed are very similar, but probably not identical, to those that mediate UV mutagenesis . Repair activities dependent on the functions of the RAD50 through RAD57 loci, the major pathway for the repair of damage caused by ionizing radiation, do not appear to play any part in mutagenesis . A comparison between the gamma-ray data and those obtained previously with UV (LAWRENCE and CHRISTENSEN 1976) and chemical mutagens (PRAKASH 1976) suggests that the RAD6 "mutagenic pathway" is in fact composed of a set of processes, some of which are concerned with error-prone, and some with error-free, recovery activities. Lipids, 1979 Oct, 14(10), 876 - 9 Identification of ergosta-8,24(28)-dien-3 beta,6 alpha-diol in A delta 8 goes to delta 7 sterol isomerase-blocked yeast mutant; Pierce AM et al.; In addition to the monohydroxysterols found in the delta 8 goes to delta 7 isomerase-blocked Saccharomyces cerevisiae mutant erg 2, a noval dihydroxysterol, ergosta-8,24(38)-dien-3 beta,6 alpha-diol, was isolated . This sterol accumulated to the extent of 2.1% of the total sterol fraction when this mutant was treated with 23-azacholesterol, a known inhibitor of the 24-methylene-sterol-24(28)-reductase. J Bacteriol, 1979 Oct, 140(1), 154 - 60 Mak mutants of yeast: mapping and characterization; Wickner RB et al.; Killer strains of Saccharomyces cerevisiae are those carrying a 1.5 x 10(6)-dalton double-stranded (ds) ribonucleic acid (RNA) (M) in virus-like particles and secreting a protein toxin . Most yeast (koller or not) also carry a 3 x 10(6)-dalton dsRNA (L) . We have mapped mutations in eight of the chromosomal genes needed for maintaining M (mak genes) . The mak genes are widely distributed on the yeast map, with no multigene complexes . We show that mutants defective in these and other mak genes lose M dsRNA, but not L dsRNA . The mak3-1 mutation results in markedly decreased cellular levels of L dsRNA, but mak3-1 stains do not lose L dsRNA completely . Mutation of mak16 results in temperature-sensitive growth, whereas mutations in mak13, mak15, mak17, mak20, mak22, and mak27 result in slow growth at any temperature . No effect of mak mutations on mating, meiosis, sporulation, germination, homothallism, or ultraviolet sensitivity has been found . The specificity of mak mutations is discussed. Proc Natl Acad Sci U S A, 1979 Oct, 76(10), 5080 - 4 Proton-dependent inhibition of yeast and brain hexokinases by aluminum in ATP preparations; Womack FC et al.; The aluminum present as a contaminant in ATP preparations can cause strong inhibition of yeast hexokinase P-II activity at pH 7.0 or below but has little or no inhibitory effect at a pH of 7.5 or greater . The inhibition is reversed by citrate, 3-phosphoglycerate, malate, phosphate, and catecholamines, all of which have previously been described as activators of hexokinase at low pH . We suggest that these agents activate the enzyme only by virtue of their ability to coordinate with aluminum present in the assay system . The presence of aluminum is also responsible for the "negative cooperativity" observed at low pH with respect to Mg . ATP concentration--i.e., the inhibition by aluminum is uncompetitive at low Mg . ATP concentrations but becomes competitive at high Mg . ATP concentrations . The inhibition is thought to be due to formation of a complex of Al . ATP with the enzyme, with a dissociation constant (Ki) of 0.1 microM . Yeast hexokinase P-I is somewhat less sensitive to A1 than is hexokinase P-II, and yeast glucokinase is not detectably affected . The hexokinase in rat brain (type I) shows a pH-dependent inhibition by Al similar to that observed with the yeast hexokinases, whereas the rat muscle (type II) enzyme is less sensitive, suggesting a possible relationship to aluminum encephalopathy in man. Biokhimiia . 1979 Oct;44(10):1906. {Comparative kinetic properties of structure-bound and solubilized L-threonine dehydratase from brewer's yeast}; Kovaleva SV et al.; It has been shown that L-threonine dehydratase (EC 4.2.1.16) of brewer's yeast Saccharomyces carlsbergensis is localized in the mitochondrial fraction . The enzyme is easily solubilized from the mitochondria by changing the pH and ionic strength of the buffer . Some kinetic properties of structure-bound and solubilized L-threonine dehydratase have been compared at pH 6,5 . The kinetic plots of the initial rate of the reaction versus initial substrate concentration for both enzymes have a hyperbolic shape; the affinities of both enzymes for the substrate appear to be similar (Km = 20 mM) . Both enzymes are inhibited by L-isoleucine, the shape of the kinetic plots being thereby changed into sigmoidal . Solubilization results in a decrease of the mitochondral enzyme sensitivity to the inhibition by L-isoleucine and in an appearance of cooperative interactions between the allosteric sites. J Biol Chem, 1979 Sep 25, 254(18), 9324 - 30 Assembly of the mitochondrial membrane system . DNA sequence of subunit 2 of yeast cytochrome oxidase; Coruzzi G et al.; A cytoplasmic "petitie" mutant of Saccharomyces cerevisiae (DS200/A1) has been isolated and determined to contain mitochondrial genetic markers in the oxi 1 locus . This locus has previously been reported to code for the structural gene of subunit 2 of cytochrome oxidase (Cabral et al . (1978) J . Biol . Chem . 243, 297-304) . The segment of mitochondrial DNA retained in DS200/A1 has a repeat length of approximately 4500 base pairs and based on DNA sequencing contains a 756-nucleotide-long sequence that has been identified as the structural gene of subunit 2 of cytochrome oxidase . The presumptive gene sequence generates an amino acid sequence consistent with the reported molecular weight and composition of subunit 2 of yeast cytochrome oxidase . The correctness of the deduced amino acid sequence is further supported by its extensive homology to the primary structure of bovine cytochrome oxidase . The DNA segment of DS200/A1 has been located on the wild type mitochondrial DNA by comparative restriction mapping . The orientation of the COOH and NH2 termini and the direction of transcription of the gene have been determined. J Biol Chem, 1979 Sep 25, 254(18), 8836 - 40 Active site phosphohistidine peptides from red cell bisphosphoglycerate synthase and yeast phosphoglycerate mutase; Han CH et al.; Bisphosphoglycerate synthase (glycerate-1,3-P2 yields glycerate-2,3-P2) and phosphoglycerate mutase (glycerate-3-P formed from glycerate-2-P) are both phosphorylated by substrates at a histidine residue forming covalent intermediates which have been shown to function in the phosphoryl transfer reactions catalyzed by these enzymes (Rose, Z . B., and Dube, S . (1976) J . Biol . Chem . 251, 4817--4822) . We have phosphorylated bisphosphoglycerate synthase from horse red blood cells with {U-32P}glycerate-2,3-P2, digested with trypsin, and purified the phosphopeptide . The amino acid sequence of the phosphohistidine peptide has been determined to be: His-Gly-Gln-Gly-Ala-Trp-Asn-Lys . In like manner, a phosphohistidyl peptide has now been purified from yeast phosphoglycerate mutase, for which the amino acid sequence is known (Winn, S . I., Watson, H . C., Fothergill, L . A., and Harkins, R . N . (1977) Biochem . Soc . Trans . 5, 657-659) . The amino acid composition of the phosphopeptide indicates that histidine-8 was phosphorylated . The sequence of this peptide is closely homologous with the active site peptide from bisphosphoglycerate synthase . In yeast phosphoglycerate mutase, the denatured phosphoenzyme hydrolyzes with a single rate constant of 2.02 X 10(-4) s-1 at pH 3, 45 degrees C . The relevance of these observations to the enzymatic mechanism is discussed. Biochemistry, 1979 Sep 18, 18(19), 4191 - 6 Isolation and characterization of fourteen ribosomal proteins from small subunits of yeast; Higo K et al.; A method for preparation of a large amount of ribosomal subunits from Saccharomyces cerevisiae by a Ti-15 zonal rotor is described . The proteins of the small subunits (ca . 50 000 A260 units) were separated into 22 fractions by chromatography on carboxymethylcellulose columns . Fourteen proteins were then purified from the ten chromatographic fractions by filtration through Sephadex G-100 or Sephacryl S--200 . The isolated proteins are YP 6, YP 7, YP 9, YP 12, YP 14', YP 14'', YP 28, YP 38, YP 45, YP 50, YP 52, YP 58, YP 63, and YP 70 . The molecular weight and amino acid compositions of these proteins are presented. Nucleic Acids Res, 1979 Sep 11, 7(1), 121 - 34 Pseudouridylation of yeast ribosomal precursor RNA; Brand RC et al.; The pseudouridylation of ribosomal RNA of Saccharomyces carlsbergensis was investigated with respect to its timing during the maturation of rRNA and its sequence specificity . Analysis of 37-S RNA, the common precursor to 17-S, 5.8-S and 26-S rRNA and most probably the primary ribosomal transcript, shows that this RNA molecule contains already most if not all of the 36-37 pseudouridine residues found in the mature rRNAs . Thus pseudouridylation is, like 2'-0-ribosemethylation, an early event in the maturation of rRNA, taking place immediately after, or even during, transcription . The data presented show that the non-conserved sequences of 37-S precursor rRNA contain very few pseudouridine residues if any . The pseudouridine residues within the rRNA sequences are apparently clustered to a certain degree as can inferred from the occurrence of a single oligonucleotide containing 3 pseudouridines, which was obtained by digestion of 26-S rRNA with ribonuclease T1. J Biol Chem, 1979 Sep 10, 254(17), 8491 - 7 Purification and molecular characterization of two inhibitors of yeast proteinase B; Maier K et al.; A rapid purification procedure for large scale preparations of yeast proteinase B inhibitors 1 and 2 (IB1 and IB2) is described . By disc gel electrophoresis, amino acid analysis, and end-group determinations, each of the inhibitors is homogeneous . Both inhibitors are polypeptides with molecular weights of 8,500, containing 74 residues . No components other than amino acids could be detected . There is no significant difference in the amino acid compositions of the two inhibitors as analyzed after acid hydrolysis . Both polypeptides are characterized by the total absence of arginine, tryptophan, and sulfur-containing amino acid residues . The proteinase B inhibitors of yeast, therefore, differ fundamentally from proteinase inhibitors of many other organisms, which generally contain a large number of disulfide bridges . Both proteinase B inhibitors have threonine as the NH2-terminal residue and -Val-His-Thr-Asn-COO- as the COOH-terminal sequence . Comparison of peptide maps after tryptic digestion reveals that the two inhibitors differ definitely in only a few tryptic peptides . The inhibitors are rapidly inactivated by digestion with carboxypeptidase A from bovine pancreas at pH 8.5 . Inactivation occurs stoichiometrically with the release of threonine, the penultimate residue at the COOH-terminal end of both inhibitors. J Biol Chem, 1979 Sep 10, 254(17), 8343 - 52 Biosynthesis of yeast mannoproteins . Synthesis of mannan outer chain and of dolichol derivatives; Parodi AJ; The Saccharomyces cerevisiae mutants affected in the structure of mannan outer chain were found to synthesize dolichol diphosphate-linked oligosaccharides identical in size to those of the wild type strain . The mannosyl transferases involved in the synthesis of the outer chain had an absolute requirement for manganese ions and were activated when enzymatic preparations were stored at 2 degrees C, whereas the transferases responsible for the formation of dolichol monophosphate mannose and dolichol diphosphate oligosaccharides were drastically inactivated from the onset of storage and required magnesium or manganese ions, the former being more effective than the latter . Both sets of enzymes could be separated by ion exchange chromatography . In vitro conditions that enhanced the synthesis of dolichol monophosphate mannose did not stimulate the incorporation of mannose residues into the outer chain . It is concluded that dolichol monophosphate mannose is not an intermediate in the synthesis of the outer chain and that this part of mannan and the dolichol diphosphate oligosaccharides are synthesized by different mannosyltransferases. Science, 1979 Sep 7, 205(4410), 1007 - 10 Genetic effects of impure and pure saccharin in yeast; Moore CW et al.; Yeast cells were grown in media containing impure or purified saccharin preparations . Dose-dependent increases in frequencies of cells possessing aberrant cell morphologies were revealed by light microscopy . At each test dose, cells grown in impure saccharin exhibited up to sevenfold higher frequencies of mitotic crossing-over or gene conversion in three of four assays for genetic recombination than cells grown in purified saccharin from the same lot . With one exception, the sweetener produced by the Maumee process caused larger increases in recombination and gene reversion than the sweetener produced by the Remsen-Fahlberg process . The several test markers did not respond equally to any test saccharin . Cells grown in liquid media containing no saccharin or two of three test concentrations of saccharin produced cell titers that were approximately equivalent. Prikl Biokhim Mikrobiol, 1979 Sep-Oct, 15(5), 660 - 4 {Optimization of the medium for the yeast synthesis of biotin}; Kole M et al.; In order to increase the yield of biotin produced by the culture Sporobolomyces pararoseus, the medium containing sucrose, asparagine, MgSO4 (NH4)2SO4, KH2PO4, vitamin complex and trace elements was optimized . With the aid of a fractional factor experiment (2(5-1)) and a complete factor experiment (2(4)), the proportion of constituents was chosen in such a way as to double biotin yield, i.e . to increase it to 55.25 micrograms/l . An enrichment of the medium with yeast autolysate, casein hydrolysate and peptone in the presence of adenine increased biotin yield to 105.7 micrograms/l and cell productivity from 6.1 to 8.0 micrograms/l dry biomass. Mikrobiologiia, 1979 Sep-Oct, 48(5), 849 - 53 {Kinetics of Candida lipolytica yeast growth and biosynthesis of alpha-keto acids with thiamine deficiency in media with different carbon sources}; Ermakova IT et al.; The growth kinetics of Candida lipolytica on glucose, acetate and hexadecane was studied in batch cultures at thiamine deficiency . The growth at the deceleration phase is of a linear character . The transition from the exponential phase to the linear one is accompanied with the accumulation of alpha-keto acids in the cultural broth, which is also observed in the stationary phase . The rate of acid production in the linear phase increases as the specific growth rate decreases, and reaches the maximum value in media with different carbon sources at mu = 0.01--0.06 h-1 . Apparently, the deceleration of growth is due to a decrease in the activity of a thiamine-dependent enzyme (pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase or transketolase) which is a limiting point of biosynthetic processes . Here, a linear growth is determined by the constant activity of this enzyme per unit volume of the cultural broth which, in turn, depends on the constant concentration of the coenzyme, thiamine diphosphate, in the same volume. Mol Gen Genet, 1979 Sep, 175(2), 217 - 21 In vitro DNA synthesis in a concentrated yeast lysate; Johnston LH; A system is described in which DNA synthesis can be monitored in a yeast lysate . The observed synthesis has many of the properties of in vivo DNA replication . It is dependent upon replication growing points that were active in vivo . The in vitro synthesis proceeds via low molecular weight intermediates, but these do not mature into larger DNA . There is a specific requirement for rATP . Mitochondrial DNA is also synthesised in this system. Mol Gen Genet, 1979 Sep, 175(2), 187 - 93 Evidence that the ribosomal DNA genes of yeast are not on chromosome I; Petes TD et al.; Several workers have reported that most of the ribosomal DNA genes (rDNA) of the yeast Saccharomyces cerevisiae are located on chromosome I . More recently, data indicating that the yeast rDNA genes are located on chromosome XII has been presented . In this report, we present additional evidence indicating that most of the yeast rDNA genes are not on chromosome I . Starting from a diploid yeast strain, we isolated ten strains which were monosomic (2n-1) for chromosome I . We found that each of these ten strains contained two copies of the rDNA-containing chromosome . In addition, we show that the earlier evidence indicating that the yeast rDNA genes were on chromosome I cannot be explained by a difference in the yeast strains which were used in the different experiments. Cell, 1979 Sep, 18(1), 37 - 45 Splicing of yeast tRNA precursors: structure of the reaction intermediates; Knapp G et al.; The intermediates of the yeast tRNA splicing reaction have been characterized . The intervening sequence is excised as an unique linear molecule . It has 5'-hydroxyl and 3'-phosphate termini . Correspondingly, the half-tRNA molecules are shown to have a 3'-phosphate terminus on the 5' half and 5'-hydroxyl terminus on the 3' half . These isolated halves have been shown to be active in the ligation step of tRNA splicing . Removal of the 3'-phosphate from the 5' half eliminates the ability of the 5' half to participate in ligation. Proc Natl Acad Sci U S A, 1979 Sep, 76(9), 4586 - 8 Evidence that a single DNA ligase is involved in replication and recombination in yeast; Fabre F et al.; The possible existence in yeast of different nuclear DNA ligase enzymes led us to ask whether induced recombination (gene conversion) involves the same ligase as that involved in DNA replication . The conditional cdc9 mutant is known to be defective, under restrictive conditions, in the rejoining of Okazaki fragments . We show here that under the same conditions, x-ray-induced convertants within the cdc9 locus are produced with kinetics indicating that most, if not all, of the conversion events require the participation of the cdc9-controlled ligase . Thus, the same DNA ligase is involved in DNA replication and in induced gene conversion. Proc Natl Acad Sci U S A, 1979 Sep, 76(9), 4285 - 8 Yeast chromatin is uniformly digested by DNase-I; Lohr D et al.; The DNase I (EC 3.1.21.1) sensitivity of transcribed yeast chromatin has been examined . We find that, in contrast to chromatin from higher eukaryotes, transcribed yeast chromatin and total yeast chromatin are equally sensitive to DNase I digestion . We interpret these results to mean that the entire yeast genome exists in a state that represents a restricted proportion of total chromatin in higher eukaryotes. Mutat Res, 1979 Sep, 62(2), 239 - 53 Genetic effects of formaldehyde in yeast . III . Nuclear and cytoplasmic mutagenic effects; Chanet R et al.; Low concentrations of formaldehyde induce nuclear mutations when yeast cells are allowed to grow in the presence of this compound . The induction of reversions is a linear function of the concentration and depends upon the repair capacities of the treated cells . A strain defective in excision-repair (rad3-12) is more mutable by formaldehyde than the isogenic wild-type whereas a strain blocked in the mutagenic pathway (rad6-1) is not mutable after the same treatment . Allele specificities were found . In particular the lys1-1 mutation is not reversible by formaldehyde . Higher concentrations of formaldehyde induce efficiently the cytoplasmic "petite" mutation in non-growing conditions when a lethal effect is noticeable . The growth phase as well as the physiological state influence this mutagenic effect . The mutagenic effect of formaldehyde in yeast is discussed in relation with the repair processes involved. Mikrobiologiia, 1979 Sep-Oct, 48(5), 937 - 42 {Use of cytofluorometry to determine the amount of DNA in yeast cells}; Landa SB; The purpose of this work was to test the possibility of using a luminescent variant of the Feulgen reaction with the reagent auramine-SO2 for staining yeast cell nuclei in order to determine the content of DNA in them . Reproducibility and stability of results obtained by this method suggest that it can be used to control the ploidy of the nuclei from yeast cells belonging to one and the same species. Int J Radiat Biol Relat Stud Phys Chem Med, 1979 Sep, 36(3), 261 - 70 The influence of oxygen on the survival and yield of DNA double-strand breaks in irradiated yeast cells; Frankenberg-Schwager M et al.; Survival and induction of DNA double-strand breaks were studied in cells of Saccharomyces cerevisiae irradiated under oxic or anoxic conditions with 30 MeV electrons . A linear relationship between DNA double-strand breakage and dose was found in both cases . The o.e.r.-value for colony forming ability was found to be 1.9 +/- 0.2, whereas the o.e.r.-value for DNA double-strand breakage was 3.0 +/- 0.1 . These results are not inconsistent with the idea that DNA double-strand breaks are involved in killing of yeast cells . The frequency of induction of DNA double-strand breaks was found to be 0.74 x 10(-11) double-strand breaks per g/mol per Gy when cells were irradiated under oxygen and 0.24 x 10(-11) double-strand breaks per g/mol per Gy under nitrogen. Proc Natl Acad Sci U S A, 1979 Sep, 76(9), 4581 - 5 Catabolite inactivation of gluconeogenic enzymes in mutants of yeast deficient in proteinase B; Zubenko GS et al.; Strains of Saccharomyces cerevisiae bearing nonsense mutations in the structural gene for proteinase B (EC 3.4.22.9) have been examined for the ability to make the transition from growth on acetate to growth on glucose and for the ability to inactivate three glucoeogenic enzymes during the transition because proteinase B has been proposed by others to be responsible for the inactivation of the three enzymes during the growth transition . The mutant strains make the growth transition normally . Catabolite inactivation of hexosediphosphatase (D-fructose-1,6-biphosphate 1-phosphohydrolase, EC 3.1.3.11), malate dehydrogenase (L-malate:NAD+ oxidoreductase, EC 1.1.1.37), and phosphoenolpyruvate carboxykinase (ATP) {ATP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.49} occurred in prb1 mutants with kinetics similar to those seen in wild-type strains . We infer that proteinase B activity is not essential for the process of catabolite inactivation. Proc Natl Acad Sci U S A, 1979 Sep, 76(9), 4265 - 9 Characterization of a histone-like protein extracted from yeast mitochondria; Caron F et al.; Analysis of proteins isolated by affinity chromatography on DNA-cellulose from highly purified yeast mitochondria shows that these organelles do not contain histones but have in abundance a DNA-binding protein of 20,000 daltons . The purification yield of this protein, called HM, indicates that mitochondria have at least an equal mass of HM relative to DNA . The amino acid composition and its electrophoretic characterization reveal that HM, rich in lysine, is slightly basic and heat stable . HM appears to be coded by the yeast nucleus, as shown by its presence in several "petite" mutants . We have shown that HM, like histones or histone-like proteins, is able to introduce superhelical turns into circular relaxed DNA in the presence of a nicking-closing activity. J Bacteriol, 1979 Sep, 139(3), 1068 - 71 Extrachromosomal psi+ determinant suppresses nonsense mutations in yeast; Liebman SW et al.; The extrachromosomal psi+ determinant in the yeast Saccharomyces cerevisiae enhanced the expression of Mendelian UAA suppressors by 6- to 10-fold . The psi+ determinant by itself is a weak UAA suppressor that caused the production of approximately 1% of the normal level of iso-1-cytochrome c in a strain containing the UAA mutation cycl-72. J Biol Chem, 1979 Aug 25, 254(16), 7746 - 51 Cytochrome c oxidase from bakers' yeast . Photolabeling of subunits exposed to the lipid bilayer; Cerletti N et al.; Yeast mitochondria and purified yeast cytochrome c oxidase incorporated into micelles of the nonionic detergent Tween 80 were equilibrated with the hydrophobic aryl azides 5-{125I}iodonaphthyl-1-azide or S-(4-azido-2-nitrophenyl)-{35S}thiophenol . The azides were then converted to highly reactive nitrenes by flash photolysis or by illumination for 2 min and the derivatized cytochrome c oxidase subunits were identified by gel electrophoresis and radioactivity measurements . 5-{125I}Iodonaphthyl-1-azide labeled mainly the three mitochondrially made Subunits I to III and the cytoplasmically made Subunit VII . Subunits IV to VI or cytochrome c bound to the purified enzyme were labeled 9- to 90-fold less . Essentially the same result was obtained with S-(4-azido-2-nitrophenyl)-{35S}thiophenol except that Subunit V was labeled as well . In contrast, all seven subunits as well as cytochrome c were heavily labeled when the enzyme was dissociated with dodecyl sulfate prior to photolabeling with either of the two probes . These data indicate that all subunits of yeast cytochrome c oxidase except Subunits IV and VI are at least partly embedded in the lipid bilayer of the mitochondrial inner membrane. Biochemistry, 1979 Aug 21, 18(17), 3796 - 804 High-resolution phosphorus nuclear magnetic resonance spectra of