ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • pharmacokinetics  (601)
  • Angiosperms  (309)
  • Immunocytochemistry  (205)
  • Ultrastructure  (196)
  • Saccharomyces cerevisiae  (187)
  • Drosophila  (181)
  • Yeast  (174)
  • Electron microscopy
  • Nitrogen fixation
  • Springer  (2,056)
  • American Chemical Society
  • Periodicals Archive Online (PAO)
  • 2000-2004  (106)
  • 1985-1989  (1,950)
Collection
Keywords
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 315-323 
    ISSN: 1476-5535
    Keywords: Sugar uptake ; Yeast ; Brewer's wort
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary When glucose and fructose are fermented separately, the uptake profiles indicate that both sugars are utilized at similar rates. However, when fermentations are conducted in media containing an equal concentration of glucose and fructose, glucose is utilized at approximately twice the rate of fructose. The preferential uptake of glucose also occurred when sucrose, which was first rapidly hydrolyzed into glucose and fructose by the action of the enzyme invertase, was employed as a substrate. Similar results were observed in the fermentation of brewer's wort and wort containing 30% sucrose and 30% glucose as adjuncts. In addition, the high levels of glucose in the wort exerted severe catabolite repression on maltose utilization in theSaccharmyces uvarum (carlsbergensis) brewing strain. Kinetic analysis of glucose and fructose uptake inSaccharomyces cerevisiae revealed aK m of 1.6 mM for glucose and 20 mM for fructose. Thus, the yeast strain has a higher affinity for glucose than fructose. Growth on glucose or fructose had no repressible effect on the uptake of either sugar. In addition, glucose inhibited fructose uptake by 60% and likewise fructose inhibited, glucose uptake by 40%. These results indicate that glucose and fructose share the same membrane transport components.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 3 (1988), S. 9-14 
    ISSN: 1476-5535
    Keywords: Single cell protein ; Sucrose ; Yeast ; Thermotolerance ; Fermentation ; Kluyveromyces marxianus var.marxianus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Amino acid analyses were undertaken on single cell protein (SCP) produced by thermotolerant strains ofKluyveromyces marxianus var.marxianus grown on sugar cane molasses at 40°C. The maximum conversion of available sugars to biomass at 45°C was only 10.8% (g dry wt.·g−1 total sugars). The amino acid composition of the SCP did not differ markedly from that reported for other yeast species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 49-53 
    ISSN: 1476-5535
    Keywords: l-Phenylacetyl carbinol ; Saccharomyces cerevisiae ; Yeast ; Benzaldehyde ; Biotransformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The rate of production ofl-phenylacetyl carbinol bySaccharomyces cerevisiae in reaction mixtures containing benzaldehyde with sucrose or pyruvate as cosubstrate was investigated in short 1 h incubations. The effect of yeast dose rate, sucrose and benzaldehyde concentration and pH on the rate of reaction was determined. Maximum biotransformation rates were obtained with concentrations of benzaldehyde, sucrose and yeast of 6 g, 40 g and 60 g/l, respectively. Negligible biotransformation rates were observed at a concentration of 8 g/l benzaldehyde. The reaction had a pH optimum of 4.0–4.5. Rates of bioconversion of benzaldehyde and selected substituted aromatic aldehydes using both sucrose and sodium pyruvate as cosubstrate were compared. The rate of aromatic alcohol production was much higher when sucrose was used rather than pyruvate.o-Tolualdehyde and 1-chlorobenzaldehyde were poor substrates for aromatic carbinol formation although the latter produced significant aromatic alcohol in sucrose-containing media. Yields of 2.74 and 3.80 g/l phenylacetyl carbinol were produced from sucrose and pyruvate, respectively, in a 1 h reaction period.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 81-84 
    ISSN: 1476-5535
    Keywords: Ethanol fermentation ; Wheat starch ; Saccharomyces cerevisiae ; immobilization ; Continuous dynamic immobilized biocatalyst bioreactor ; Biocatalyst bioreactor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A simple and efficient method of conversion of wheat starch B to ethanol was investigated. Employing a two-stage enzymatic saccharification process, 95% of the wheat starch was converted to fermentable sugars in 40 h. From 140 g/l total sugars in the feed solution, 63.6 g/l ethanol was produced continuously with a residence time of 3.3 h in a continuous dynamic immobilized biocatalyst bioreactor by immobilized cells ofSaccharomyces cerevisiae. The advantages and the application of this bioreactor to continuous alcoholic fermentation of industrial substrates are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 24 (1985), S. 113-119 
    ISSN: 1436-6215
    Keywords: Chloramphenicol ; pharmacokinetics ; residue ; pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary Residues of Chloramphenicol (CAP) were examined in 24 pigs after intramuscular injection of 30 mg CAP/kg body weight. Two pigs were slaughtered after 3, 6, 12,18, 24, 36 hours, 2, 3, 6, 10, 21 and 30 days, respectively. CAP-concentrations were determined in muscle, blood, urine, liver, kidney, bile, and fat. Methods used were gas-liquid chromatography and radioimmunoassay. Detection limits reached were 1−5 ppb. The concentration-time curves obtained reflected a long elimination phase and allowed only calculation of this half-life. Elimination half-life was estimated to be for muscle, blood and urine 160–170 hours, for kidney 310 and for bile 250 hours. Significant correlations were found to exist between CAP-concentrations in plasma and muscle. It appears that blood would be a good body fluid for monitoring CAP-residues in tissue.
    Notes: Zusammenfassung Zur Untersuchung des Rückstandsverhaltens von Chloramphenicol (CAP) wurden 24 Mastschweine, 24–28 Wochen alt, intramuskulär mit 30 mg CAP/kg Körpergewicht behandelt und je 2 Tiere nach 3, 6, 12, 18, 24, 36 Stunden, 2, 3, 6, 10, 21 und 30 Tagen geschlachtet. Die CAP-Gehalte in Muskulatur, Blut, Urin, Leber, Niere, Galle und Fett wurden gaschromatographisch und radioimmunologisch bestimmt. Die Nachweisgrenze beider Methoden liegt in Abhängigkeit von der Matrix zwischen 1 und 5 ppb. Die erhaltenen Kinetiken weisen eine terminale Elimination auf, deren Halbwertszeiten für Muskulatur, Blut und Urin ca. 160–170 Stunden, für Niere 310 Stunden und für Galle 250 Stunden betragen. Die CAP-Konzentration in Muskulatur und Blut weisen eine signifikante, lineare Korrelation auf. Blutuntersuchungen könnten deshalb als Screening-Methode bei umfangreichen Rückstandskontrollen eingesetzt werden.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 263 (1985), S. 116-119 
    ISSN: 1435-1536
    Keywords: Electron microscopy ; staining ; morphology ; nylon-12 ; orientation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The morphology of drawn and annealed sheets of nylon-12 was investigated by transmission electron microscopy of stained sections, and the results compared with equivalent small-angle X-ray scattering (SAXS) patterns. A three-component structure was observed, consisting of crystalline (C) and amorphous (A) regions in the microfibrils and an interfibrillar component whose density was deduced to be intermediate between that of the C and A regions. The crystallite width was given satisfactorily by a Guinier analysis of the SAXS profile.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 94 (2000), S. 159-171 
    ISSN: 1570-7458
    Keywords: Drosophila ; induction ; habituation ; associative learning ; T-maze olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments reported in this paper investigate the properties of a change in the responsiveness of adult Drosophila melanogaster induced by exposure to different rearing media. This effect has previously been described as habituation or associative learning. Exposure to food medium containing 0.08% menthol induced a positive response to menthol odour in a T-maze olfactometer. A brief (one hour) exposure to mentholic food just before testing was sufficient to induce a change in responsiveness. The effect did not persist through periods of more than an hour of separation from mentholic medium. Effects induced by exposure to a single compound were not specific to that compound alone. Menthol-reared flies (MRFs) differed from plain reared flies (PRFs) in their responsiveness to the odours of benzaldehyde and ethyl acetate, as well as menthol, and exposure to ethyl acetate induced a change in response to menthol odour. That there was an induced positive response to menthol in MRFs suggests that conventional habituation is insufficient to explain the induced change in responsiveness, but the generalised nature of this behavioural induction in MRFs is hard to explain in terms of associative learning. The mechanism underlying the induction remains elusive.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1572-8889
    Keywords: courtship song ; wingbeat ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1572-8889
    Keywords: Drosophila ; copulatory courtship ; mate choice ; cryptic female choice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two endemic Australian Drosophila species, D. birchii and D. serrata, have a copulatory courtship, i.e., the males court the female mainly during copulation. In the present study we found the males of both species to mount their prospective mating partners selectively, exhibiting both sex and species recognition. The males began to sing after mounting the female, and they often exhibited also postcopulatory displays typical to copulatory courtship. D. birchii and D. serrata females discriminated against males which did not sing during mounting/copulation, which suggests that the females utilize cryptic female choice. Our findings raise the question of how widespread a phenomenon cryptic female choice is in Drosophila species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 1 (1988), S. 3-15 
    ISSN: 1572-8889
    Keywords: host preference ; habitat selection ; experience ; learning ; Drosophila ; host races ; population genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A field experiment with Drosophila melanogasterrevealed that when flies encounter a particular food type soon after emergence, the probability of their subsequently being attracted to such a resource is increased. In this experiment, the length of time flies experienced their postemergence environments was under the control of the flies themselves. The experiment thus realistically mimicked one form of experiential effect that may be important in nature. A theoretical model is developed which shows that enhanced adult preferences for the types of resources fed on as larvae can substantially increase the degree of host-based genetic subdivision within a polyphagous population.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    ISSN: 1572-8773
    Keywords: major facilitator superfamily ; iron transport ; siderophores ; enterobactin ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract While in fungi iron transport via hydroxamate siderophores has been amply proven, iron transport via enterobactin is largely unknown. Enterobactin is a catecholate-type siderophore produced by several enterobacterial genera grown in severe iron deprivation. By using the KanMX disruption module in vector pUG6 in a fet3Δ background of Saccharomyces cerevisiae we were able to disrupt the gene YOL158c Sce of the major facilitator super family (MFS) which has been previously described as a gene encoding a membrane transporter of unknown function. Contrary to the parental strain, the disruptant was unable to utilize ferric enterobactin in growth promotion tests and in transport assays using 55Fe-enterobactin. All other siderophore transport properties remained unaffected. The results are evidence that in S. cerevisiae the YOL158c Sce gene of the major facilitator super family, now designated ENB1, encodes a transporter protein (Enb1p), which specifically recognizes and transports enterobactin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1572-8773
    Keywords: Manganese ; Electron spin resonance ; Superoxide dismutase ; Saccharomyces cerevisiae ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Manganese accumulation was studied by room-temperature electron spin resonance (ESR) spectroscopy inSaccharomyces cerevisiae grown in the presence of increasing amounts of MnSO4. Mn2+ retention was nearly linear in intact cells for fractions related to both low-molecular-mass and macromolecular complexes (‘free’ and ‘bound’ Mn2+, respectively). A deviation from linearity was observed in cell extracts between the control value and 0.1 mM Mn2+, indicating more efficient accumulation at low Mn2+ concentrations. The difference in slopes between the two straight lines describing Mn2+ retention at concentrations lower and higher than 0.1 mM, respectively, was quite large for the free Mn2+ fraction. Furthermore it was unaffected by subsequent dialyses of the extracts, showing stable retention in the form of low-molecular-mass complexes. In contrast, the slope of the line describing retention of ‘bound’ Mn2+ at concentrations higher than 0.1 mM became less steep after subsequent dialyses of the cell extracts. This result indicates that the macromolecule-bound Mn2+ was essentially associated with particulate structures. In contrast to Cu2+, Mn2+ had no effect on the major enzyme activities involved in oxygen metabolism except for a slight increase of cyanide-resistant Mn-superoxide dismutase activity, due to dialyzable Mn2+ complexes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 116 (1985), S. 1233-1236 
    ISSN: 1434-4475
    Keywords: Stereoselective reduction ; (S)-1-Phenylethanol ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The velocity of reduction of 4-substituted acetophenones by baker's yeast is decreased by electron donating substituents. The steric course, however, is little influenced and (S)-1-arylethanols2 are generally formed with over 90% enantiomeric excess.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    ISSN: 1433-4909
    Keywords: Key words Xylanases ; Psychrophile ; Yeast ; Molecular adaptation ; Molecular modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A xylanase belonging to family 10 is produced by Cryptococcus adeliae, an Antarctic yeast that exhibits optimal growth at low temperature. The mature glycosylated xylanase secreted by C. adeliae is composed of 338 amino acid residues and 26 ± 3 osidic residues, and shares 84% identity with its mesophilic counterpart from C. albidus. The xylanase from C. adeliae is less thermostable than its mesophilic homologue when the residual activities are compared, and this difference was confirmed by differential scanning calorimetry experiments. In the range 0°–20°C, the cold-adapted xylanase displays a lower activation energy and a higher catalytic efficiency. All these observations suggest a less compact, more flexible molecular structure. Analysis of computerized molecular models built up for both psychrophilic and mesophilic xylanases indicates that the adaptation to cold consists of discrete changes in the tridimensional structure: of 53 substitutions, 22 are presumably involved in the adaptation process. These changes lead mainly to a less compact hydrophobic packing, to the loss of one salt bridge, and to a destabilization of the macrodipoles of the helices.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 1554-1557 
    ISSN: 1420-9071
    Keywords: Immunocytochemistry ; neuropeptide Y ; radioimmunoassay ; rat pancreas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 43 (1987), S. 886-888 
    ISSN: 1420-9071
    Keywords: Saccharomyces cerevisiae ; trichothecenes ; mycotoxins ; vitamins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several trichothecene mycotoxins were shown to inhibit the growth ofSaccharomyces cerevisiae. This effect was most pronounced with the macrocyclic trichothecenes, especially verrucarin A. Much less growth inhibition was observed with T-2 toxin. Verrucarol, diacetoxyscirpenol, acetyl T-2 toxin, HT-2 toxin, T-2 tetraol and neosolaniol were inactive at a concentration of 75 μg of toxin per disc. Incubation ofS. cerevisiae with verrucarin A together with vitamins resulted in a decrease in toxicity. Pyridoxine-HCl, Ca-pantothenate, thiamine-HCl and α-tocopheryl acetate were amongst the most potent of the vitamins tested which reversed growth inhibition, overcoming the inhibitory potential of the toxins.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 43 (1987), S. 888-890 
    ISSN: 1420-9071
    Keywords: Thiaminase ; thiamine ; thiamine antagonist ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It was found that cell-free extracts ofSaccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1420-9071
    Keywords: Interferon ; immunomodulator ; catabolism ; pharmacokinetics ; administration routes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When human recombinant interferon-α2 diluted in saline was injected s.c. into rabbits, the total amount recovered in thoracic lymph was less than 0.4%. Recoveries increased from 2- to 8-fold if interferon was injected in 4% albumin or with hyaluronidase, respectively. Albumin added to interferon acts as an interstitial fluid expander, thus favoring interferon absorption through lymphatics rather than blood capillaries. This strategy may increase the therapeutic index of interferon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 143-147 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Drosophila ; parasitoid ; habitat toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'étude a porté sur la tolérance et l'utilisation de vapeurs d'éthanol, d'acide acétique et d'acétaldéhyde par Asobara persimilis (Hym. Braconidae), parasitoïde de Drosophila récemment découvert en Australie. Aux faibles concentrations, il n'y a pas d'utilisation significative d'éthanol et d'acide (respectivement moins de 1,5% et 0,1%), cependant la longévité des mâles et des femelles ont augmenté avec les concentrations d'acide acétique de 1,0 et 1,5%. Toutes ces substances sont toxiques à plus forte concentrations, bien qu'il y ait un dimorphisme sexuel et que les femelles survivent significativement plus longtemps que les mâles. La tolérance des braconides est inférieure à celle de leurs hôtes, les Drosophiles cosmopolites et endémiques à l'Australie. Ceci peut faire que ces parasites limitent l'exploitation de leurs hôtes aux habitats avec une faible concentration de produits de fermentation.
    Notes: Abstract The tolerance and utilization of ethanol, acetic acid and acetaldehyde vapour was investigated in Asobara persimilis (Hymenoptera: Braconidae), a parasitoid of Drosophila. No significant utilization of ethanol or acetaldehyde occurred at low concentrations (〈 1.5% and 0.1% respectively), however both female and male longevity was increased at concentrations of 1.0 and 1.5% acetic acid. All substances were toxic at higher concentrations, but there was sexual dimorphism in that females survived significantly longer than males.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 2 (1989), S. 50-54 
    ISSN: 1572-8773
    Keywords: Cu(I)8-thionein ; Yeast ; Extracellular ; Circular dichroism ; Fluorescence ; Electronic absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The release of intact CU(I)8-thionein from copper-resistant copper-loaded yeast cells, strain X 2180-1Aa, has been shown. This copper(I)-thiolate-rich protein was characterized and compared with the chemical and physicochemical properties of intracellular yeast Cu-thionein. The same molecular mass and stoichiometry of 8 mol copper atoms/mol protein was found. No detectable difference between the Cu-thioneins was seen in luminescence emission, electronic absorption in the ultraviolet region, chiroptical data or amino acid composition. The importance of stable Cu(I)-thiolates in Cu-thionein as a safe vehicle for transporting copper in a non-reactive manner is confirmed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 43 (1987), S. 193-201 
    ISSN: 1570-7458
    Keywords: Leptopilina boulardi ; Cynipidae ; Hymenoptera ; parasitoid ; Drosophila ; Diptera ; field egg laying strategy ; functional response ; switching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le concept de réponse optimale d'un parasite vis-à-vis de l'hôte le plus favorable pour son développement demeure surtout théorique et n'a pu être vérifié que dans les conditions de laboratoire. Nous avons montré que Drosophila melanogaster s'avère être, par rapport à D. simulans, l'hôte le plus favorable pour le développement du cynipide parasite Leptopilina boulardi. Une étude sur le terrain a démontré que ce parasite présente une réponse fonctionnelle densité dépendante vis-à-vis de D. melanogaster et non vis-à-vis de D. simulans, avec un effet de bascule. D'autre part, il s'avère que ce parasite exploite beaucoup mieux son hôte, en évitant le superparasitisme, ceci étant démontré au laboratoire et dans la nature. Enfin, il apparaît qu'il est capable d'allonger sa période de ponte lorsque cet hôte est rare, ce qui ne se produit pas avec D. simulans.
    Notes: Abstract The hypothesis of optimal host species selection predicts that when a parasitoid has the choice between two host species, it will choose the species thay gives the best survival chances for its progeny. We confirmed this hypothesis by laboratory experiments with Leptopilina boulardi Barb. et al., a cynipid parasitoid which prefers Drosophila melanogaster Meigen (the host species most suitable for parasitoid survival) above D. simulans Sturt. As far as fitness parameters are concerned, the fertility of L. boulardi is higher with D. melanogaster; the egg laying can be spread out over a long period when this host is relatively scarce. This does not occur with D. simulans in which parasitic oviposition stops soon when this host is not abundant. Investigations of this foraging strategy were done under more complex natural conditions. We found that L. boulardi has a type III functional response with D. melanogaster only; furthermore, it seems that a switching effect may exist with this host. Parasitoid females appear to distribute their eggs more regularly on D. melanogaster, thus avoiding superparasitism. This seems to be independent of the relative frequency of this host. However, superparasitism of D. simulans did occur more frequently when this host was scarce.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 47 (1988), S. 81-88 
    ISSN: 1570-7458
    Keywords: imaginal diapause ; male mating activity ; genetics ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les femelles de D. triauraria Bock & Wheeler (Dipt. Drosophilidae) sont connues pour présenter une diapause reproductrice aux photophases courtes. Les mâles eux aussi ont révélé une activité sexuelle réduite aux photophases courtes, c'est-à-dire qu'ils sont entrés comme les femelles en diapause reproductive. Les photophases critiques pour l'induction de la diapause des mâles et des femelles n'ont pas présenté de différences. Les diapause des mâles et des femelles s'achèvent même sous courtes photophases, mais la diapause mâle était quelque peu plus faible que la diapause femelle. La photophase critique et le taux de diapause ont varié en fonction de l'origine géographique dans l'espèce actuelle. Lors de croisements entre lignées diapausantes et non-diapausantes, la photophase critique et la durée de la diapause ont été héritées quantitativement. A partir de ces expériences et d'expériences précédentes de croisements (Kimura, 1983), quelques modèles de méchnisme d'induction de la diapause de cette espèce sont proposés.
    Notes: Abstract In Drosophila triauraria Bock & Wheeler (Diptera: Drosophilidae) of which females were known to enter reproductive diapause at short daylengths, males also showed reduced mating activity at short daylengths, i.e., males as well as females entered reproductive diapause. The critical daylength for diapause induction did not differ between females and males. Both male and female diapause ended even under short daylengths, but the male diapause was somewhat weaker than the female diapause. The critical daylength and the diapause rate varied geographically in this species. In the cross between diapausing and non-diapausing strains, the critical daylength and the diapause duration inherited in a quantitative manner. On the basis of the present and previous crossing experiments, some models are proposed on the mechanism of diapause induction of this species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 4 (1987), S. 61-66 
    ISSN: 1432-0789
    Keywords: Stem nodulation ; Aeschynomene afraspera ; Legume ; Nitrogen fixation ; Acetylene reduction assay (ARA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Aeschynomene afraspera is a wild annual legume growing in periodically waterlogged soils in western Africa. This legume is characterized by a profuse stem nodulation. Nodules are formed on the stem at the emergence of lateral root primordia, called nodulation sites. These sites are irregularly distributed on vertical rows all along the stem and branches. Stem nodules are hemispherically shaped. Their outside is dark green and they contain a red-pigmented central zone. Stem nodules exhibit a high nitrogen-fixing potential. Acetylene reduction assays result in stem nodule activity of 309 μmol C2H4 g−1 dry nodule h−1. Field-grown stem nodulated Aeschynomene accumulated more N (51 g N m−2 in 10 weeks) than the root nodulated one. Because of this nitrogenfixing potential and its ability to grow in waterlogged conditions, A. afraspera could probably be introduced into tropical rice cropping systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 8 (1989), S. 356-368 
    ISSN: 1432-0789
    Keywords: Plant-root associations ; Azospirillum spp ; Rhizosphere ; Nitrogen fixation ; Acetylene reduction assay (ARA) ; Phytohormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Bacteria of the genus Azospirillum are extensively studied for their plant-growth promoting effect following inoculation. Physiological and biochemical studies of these diazotrophic bacteria are now benefiting from recent breakthroughs in the development of genetic tools for Azospirilum. Moreover, the identification and cloning of Azospirillum genes involved in N2 fixation, plant interaction, and phytohormone production have given new life to many research projects on Azospirillum. The finding that Azospirillum genes can complement specific mutations in other intensively studied rhizosphere bacteria like Rhizobia will certainly trigger the exploration of new areas in rhizosphere biology. Therefore a review of the Azospirillum-plant interactions is particularly timely.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 30 (2000), S. 363-373 
    ISSN: 1432-0789
    Keywords: Key words Azospirillum species ; Oxygen paradox ; Nitrogen fixation ; Rhizosphere ; Nitrogenase complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  N2 fixation by aerobic bacteria is a very energy demanding process, requiring efficient oxidative phosphorylation, while O2 is toxic for the nitrogenase complex. N2-fixing bacteria have evolved a variety of strategies to cope with this apparent "O2 paradox". This review compares strategies that azospirilla and other well-known N2-fixing soil bacteria use to overcome this O2 paradox. Attention will be given to the relationships between the natural habitat of these soil bacteria and their prevailing adaptations. In view of this knowledge the following questions will be addressed: are the specific adaptations observed in azospirilla sufficient to allow optimal proliferation and N2 fixation in their natural habitat? Could improving the O2 tolerance of the N2-fixing process contribute to the development of more efficient strains for the inoculation of plants?
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 5 (1987), S. 83-87 
    ISSN: 1432-0789
    Keywords: Inoculation ; Inoculum dose ; Nitrogen fixation ; Chickpea ; Rhizobium spp. ; Cicer arietinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The influence of three inoculum rates on the performance of three chickpea (Cicer arietinum L.) Rhizobium strains was examined in the field on a Mollisol soil. Increasing amounts of inoculum improved the performance of the strains. A normal dose (104 cells per seed) applied at different intervals gave non-significant increases in nodulation, nitrogenase activity (acetylene reduction assay), nitrogen uptake and grain yield. A ten-fold increase in inoculum increased nodule number, shoot dry weight, nitrogenase activity (ARA) and grain yield, but increases over the control were significant only for nodule dry weight and nitrogen uptake by shoot and grain. The highest level of inoculum (100 × normal) significantly increased nodule dry weight, grain yield, total nitrogenase activity (ARA) and nitrogen uptake by shoot and grain. Strain TAL 620 was more effective than the other two. Combined nitrogen (60 kg N ha−1) suppressed nodulation and nitrogenase activity (ARA).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 6 (1988), S. 39-44 
    ISSN: 1432-0789
    Keywords: Alnus ; Energy forestry ; Frankia ; Meadow soil ; Nitrogen fixation ; Nodulation ; Peat soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Use of the N2-fixing grey alder, Alnus incana (L.) Moench, as a short-rotation crop for energy production is currently being explored. To evaluate the need for inoculation of alders, the distribution of infective propagules of Frankia in the soil at potential sites for alder plantations was examined. Uninoculated grey alder seedlings were grown in three types of soil. Frequent nodulation was found in a meadow soil which had been free from actinorhizal plants for nearly 60 years, but the alder seedlings failed to nodulate in peat soil from two different bog sites. One of these bogs had been exploited for peat and the surface layer of the peat had been removed, so that the soil samples were taken from deep layers of the peat. At the other site, an area of cultivated peat, there were no infective propagules of Frankia in plots without alders; the infective Frankia was present in plots only where it had been introduced by inoculated alders. There was no detectable air-borne dispersal of Frankia. Instead, water movement might account for the dispersal of Frankia in peat. Although the apparent absence of Frankia in these peat soils necessitates inoculation of alder seedlings before planting out, this makes it possible to introduce and maintain Frankia strains with selected beneficial characteristics, since there is no competition from an indigenous Frankia flora.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1432-0789
    Keywords: Key words Genetic variability ; Vigna unguiculata ; Nitrogen-15 method ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  N fixed in 16 cultivars of cowpea [Vigna unguiculata (L.) Walp] inoculated with effective Bradyrhizobium strains collected from the West African MIRCEN culture collection was measured by 15N isotope dilution technique. In all plant parts, significant differences in the percentage of N derived from the atmosphere (%Ndfa) and the amount of Ndfa occurred between the cultivars. Ndoute variety exhibited the highest %Ndfa (74.33% in shoots; 60.90% in roots) and accumulated more fixed N (960 mg N plant–1 and 38 mg N plant–1 in shoots and roots, respectively). Therefore this cultivar should be selected as the highest N-fixing cowpea cultivar. It also should be used in a breeding programme to contribute to the development of cultivars that could stimulate an intensive use of cowpea in many different cropping systems in Africa with a view to maintaining soil fertility.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 1432-0789
    Keywords: Nodule damage ; Rivellia angulata ; Nitrogen fixation ; Cajanus cajan ; Pigeonpea ; Vertisol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Damage caused by Rivellia angulata larvae to pigeonpea root nodules at the ICRISAT center in India was greater in the crop grown on Vertisols (up to 86%) compared to that on Alfisols (20%). Attempts to quantify the field effects of nodule damage on growth and yield of pigeonpea in a Vertisol, involving many heavy applications of soil insecticides (aldrin and hexachlorocyclohexane) failed because the insecticides did not control the pest and adversely affected the growth of the pigeonpea and the subsequent crop of sorghum (Sorgorum bicolor L. Moench). The impact of nodule damage on pigeonpea growth, yield and nutrient uptake was successfully studied in greenhouse-grown plants at three N levels. In this pot study, artificial inoculation with Rivellia sp. led to substantial nodule damage (70%). The results of this damage were a significant overall reduction in nodule dry weight (46%), acetylene reduction activity (31%), total leaf area (36%), chlorophyll content of leaves (39%) and shoot dry weight (23%) 68 days after sowing. At maturity, Rivellia sp. infestation caused significant reductions in top dry weight (22%), root and nodule dry weight (27%), seed dry weight (14%), and total N (29%) and P uptake (19%). The problems and prospects of manipulating nodule damage so as to reduce N losses in pigeonpea are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1432-0789
    Keywords: Triticum aestivum ; T. turgidum ; Nitrogen fixation ; Field inoculation ; Acetylene reduction assay (ARA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight commercial Israeli spring wheat cultivars (six Triticum aestivum and two T. turgidum) grown with 40 and 120 kg N/ha were tested for responses to inoculation with Azospirillum brasilense. At the low level of N fertilization (40 kg/ha), five cultivars showed significant increases in plant dry weight measured at the milky ripe stage; however, by maturation only the cultivar “Miriam” showed a significant increase in grain yield. Two cultivars, which had shown a positive inoculation effect at the earlier stages, had a significant decrease in grain yield. No significant effect of inoculation was found at the high N level. To confirm those results, four wheat (T. aestivum) cultivars were tested separately over 4 years in 4 different locations under varying N levels. Only Miriam showed a consistently positive effect of Azospirillum inoculation on grain yield. Inoculation increased the number of roots per plant on Miriam compared with uninoculated plants. This effect was found at all N levels. Nutrient (N, P and K) accumulation and number of fertile tillers per unit area were also enhanced by Azospirillum, but these parameters were greatly affected by the level of applied N. It is suggested that the positive response of the spring wheat cultivar “Miriam” to Azospirillum inoculation is due to its capacity to escape water stresses at the end of the growth season.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 4 (1987), S. 15-19 
    ISSN: 1432-0789
    Keywords: Nitrogen fixation ; N-balance studies ; Azolla ; Blue-green algae ; Chemical N fertilization ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A nitrogen balance study conducted in ceramic pots under net house conditions for four seasons showed that flooded rice soil leaves a positive nitrogen balance (N increase) in soil after rice cropping in both fertilized and unfertilized soil. Recovery of nitrogen from rice soil was more than its input in unfertilized soil, but it was reverse in fertilized soil. Incorporation of Azolla or BGA twice as basal and 20 days after transplanting (DAT) alone or in combination showed higher nitrogen balance and N2-fixation (N gain) in soil than in that where it was applied once either as basal or 20 DAT. Planted soil showed more N2-fixation than that of fallow rice, and flooded soil fixed more nitrogen in comparison to non-flooded soil in light but less in dark. Soil exposed to light fixed more nitrogen than that of unexposed soil in both flooded and non-flooded conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 4 (1987), S. 9-14 
    ISSN: 1432-0789
    Keywords: Rhizosphere ; Nitrogen fixation ; Root exudates ; Soil bacteria ; Carbon budget ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The association of rice seedlings (cv. Delta) with different strains of Azospirillum was studied under monoxenic conditions in the dark. Axenic 3-day-old seedlings were obtained on a C- and N-free medium and inoculated with 6 · 107 bacteria per plant in a closed vial. Seven days later, different components of a carbon budget were evaluated on them and on sterile controls: respired CO2, carbon of shoot and roots, bacterial and soluble carbon in the medium. Two strains (A. lipoferum 4B and A. brasilense A95) isolated from the rhizosphere of rice caused an increase in exudation, + 36% and + 17% respectively compared with sterile control. Shoot carbon incorporation and respiration were reduced by inoculation. A third strain (A. brasilense R07) caused no significant change in exudation. A. lipoferum B7C isolated from maize did not stimulate rice exudation either. We further investigated a possible effect of nitrogen fixation on this phenomenon: inhibition of nitrogen fixation by 10% C2H2 did not modify the extent of C exudation by rice associated with A. lipoferum 4B or with the non-motile A. lipoferum 4T.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1432-0789
    Keywords: Key words Nitrogen-15 isotope dilution ; Legumes ; Lens culinaris ; Rhizobium ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  A 15N isotope dilution technique was applied to quantify the extent of N2 fixation in lentil (Lens culinaris Medik.) cultivars as influenced by Rhizobium leguminosarum bv. viciae strains in a field experiment in Pakistan. The experiment was conducted on a soil with a very small indigenous rhizobial population and where N was a limiting factor for crop production. Significant variations in number of nodules, dry weight of nodules, biomass yield, grain yield, total N yield, proportion of plant N derived from N2 fixation (Pfix) and amount of N derived from the atmosphere (Ndfa) were observed among combined treatments of four rhizobial strains and six lentil varieties. In a field previously labelled with 15N, to which a basal dose of 75 kg P2O5 ha–1 was applied as single super phosphate, Ndfa ranged from 15 to 24 kg N ha–1 when calculated according to rhizobial strain and from 4 to 38 kg N ha–1 when calculated according to lentil variety. Lc 26 was the most effective strain and fixed 243% more N than the indigenous population in the uninoculated control. In treatments with the lentil variety PL-406, Ndfa was 38 kg N ha–1, which was 850% higher than with the lentil variety Precoz/F6-20-1×M-85. Generally, the varieties with greater Pfix produced a higher dry matter yield.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 30 (2000), S. 485-491 
    ISSN: 1432-0789
    Keywords: Key words Herbaspirillum seropedicae ; Burkholderia spp. ; Nitrogen fixation ; Rice ; Gnotobiotic conditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Four experiments were performed under gnotobiotic conditions to select strains of the endophytic diazotrophs Herbaspirillum seropedicae and Burkholderia spp. as inocula of rice plants. Eighty strains of H. seropedicae originally isolated from rice, sorghum and maize plants, were tested in test tube cultures with N-free agar as the substrate. Rice plants showed medium and high increases in their fresh weight in response to inoculation with nineteen strains. These strains were tested again, and six strains were then selected to evaluate their contribution to the N of the plant via biological N2 fixation (BNF) using an agar growth medium containing 5 mg N l–1of 15N-labelled (NH4)2SO4. The contribution of the strains to plant N via BNF varied from 54% when rice plants were inoculated with strain ZAE94, to 31% when strain ZAE67 was used. These results were confirmed in the fourth gnotobiotic experiment, which also included strains of the new N-fixing bacteria belonging to the genus Burkholderia, isolated from rice, as well as a strain of Burkholderia vietnamiensis, isolated from rice rhizosphere. Burkholderia spp. strains showed similar effects to those observed for H. seropedicae strains, while B. vietnamiensis fixed only 19% of plant total N. The best four strains were tested in a pot experiment where pre-germinated, inoculated rice seedlings were grown in soil labelled with 15N. The results confirmed the gnotobiotic experiments, although the levels of N in the rice plants derived from BNF of the selected H. seropedicae and Burkholderia spp. strains were lower. Nevertheless, there was an increase in N content in grains of inoculated plants, and the results showed that the method used for strain selection is very useful and can be applied to other strains of N2-fixing bacteria and plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1432-0789
    Keywords: Key words Fallow ; Legumes ; Nitrogen fixation ; Oryza sativa ; Côte d'Ivoire
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Improving fallow quality in upland rice-fallow rotations in West Africa through the site-specific use of leguminous cover crops has been shown to sustain the productivity of such systems. We studied the effects of a range of residue management practices (removal, burning, mulching and incorporation) on fallow biomass and N accumulation, on weed biomass and yield response of upland rice and on changes in soil physical and chemical characteristics in 2-year field trials conducted in three agroecological zones of Côte d'Ivoire. Across fallow management treatments and agroecological zones, rice yields were on average 20–30% higher in legume than in natural fallow plots. Weed biomass was highest in the savanna zone and lowest in the bimodal forest and tended to be less following a legume fallow. Regardless of the type of fallow vegetation and agroecological zone, biomass removal resulted in the lowest rice yields that varied from 0.5 t ha–1 in the derived savanna zone to 1.5 t ha–1 in the Guinea savanna zone. Burning of the fallow vegetation significantly increased yield over residue removal in the derived savanna (0.27 t ha–1, P〈0.05) and bimodal forest zones (0.27 t ha–1, P〈0.01), but not in the Guinea savanna. In both savanna environments, residue incorporation was superior to the farmers' practice of residue removal and rice yield increases were related to amounts of fallow N returned to the soil (r 2=0.803, P〈0.01). In the forest zone, the farmers' practice of residue burning produced the highest yield (1.43 t ha-1 in the case of legumes) and resulted in the lowest weed biomass (0.02 t ha–1). Regardless of the site, improving the quality of the fallow or of its management had no significant effects on either soil physical or soil chemical characteristics after two fallow cycles. We conclude that incorporation of legume residues is a desirable practice for rice-based fallow rotation systems in savanna environments. No promising residue management alternatives to slash-and-burn were apparent for the forest zone. Determining the possible effects on soil productivity will require longer-term experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 7 (1989), S. 269-274 
    ISSN: 1432-0789
    Keywords: Nitrogen fixation ; Frankia-Ceanothus spp. association ; Acetylene reduction assay (ARA) ; Microsymbiont population ; Nodules ; Actinomycetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wildland shrub improvement is needed for sound range and disturbed land revegetation practice. The possibility of selecting superior N2-fixingFrankia-Ceanothus spp. actinorhizal associations was examined. Greenhouse tests were used to expose various soil-borne microsymbiont andCeanothus sp. population accessions in reciprocal combination. The acetylene reduction rate was used as a measure of N2-fixation capacity. There was no significant interaction between host and microsymbiont regardless of source for all variables measured. The acetylene reduction rate, nodule number and mass, plant biomass, and root: shoot ratio were significantly different among soil sources. The acetylene reduction rate was not significantly different amongCeanothus sp. accessions. Neither was it strongly correlated with other variables. It was concluded that the N2-fixation rate is more a function ofFrankia sp. than the hostCeanothus sp. in actinorhizal associations. It appears possible to select soil sources with superior N2-fixing microsymbiont populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 6 (1988), S. 279-281 
    ISSN: 1432-0789
    Keywords: Sesbania rostrata ; Green manure ; Biofertilizer ; Nitrogen fixation ; Stem nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ratooning and stem cutting were compared with seeding in order to reduce the amount of seeds of Sesbania rostrata for green-manure growth. Both methods increased the biofertilizer yield highly significantly within a 6-week growth period.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 12 (1987), S. 577-582 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Cell cycle ; Cyclic AMP ; G0 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When the cyr1-1 cells of Saccharomyces cerevisiae, which require cyclic AMP (cAMP) for growth, were starved for cAMP, cell division was arrested at the G1 state of the mitotic cell cycle and the cells entered the resting state (G0) also observed in wild-type cells transferred to sulfur-free medium. The level of cAMP in wild-type cells decreased rapidly when the cells were starved for sulfur and subsequently increased following its addition. The cyr1-1 cells starved for cAMP preferentially synthesized nine G0 proteins. The synthesis of these G0 proteins in the sulfur-starved cells was repressed by the addition of cAMP. The RAS2 val19 or bcy1 cells, which produced an elevated level of cAMP or cAMP-independent protein kinase, did not synthesize the G0 proteins under the sulfur-starved condition. The results suggest that cAMP plays a role in the transition between the proliferating state and G0 state.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1432-0983
    Keywords: Ribosomal protein ; Immunological homology ; Yeast ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polyclonal antibodies raised against ribosomal protein (r-protein) L2 of Schizosaccharomyces pombe were used to check for cross-reaktions with total r-proteins of rat liver. Using this procedure, the rat liver r-proteins, L4 and L24, were identified as being immunologically related to yeast L2. In addtional, homologies between rat liver L4 and L24 were detected. The possible implications for the regulation of r-protein synthesis are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 13 (1988), S. 291-297 
    ISSN: 1432-0983
    Keywords: Yeast ; Nuclear matrix ; Plasmid stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Acentric yeast plasmids are mitotically unstable, apparently because they cannot freely diffuse after replicating and therefore are not included in the daughter nucleus. This behavior could result if plasmids remain attached to structural elements of the nucleus after replicating. Since DNA replication is believed to take place on the nuclear matrix, we tested whether there was a correlation between the mitotic stability of a given plasmid and the extent to which it was found associated with residual nuclear structures. Residual nuclei were prepared from yeast nuclei by extraction with either high salt, 2 M NaCl, or low salt, 10 mM lithium diiodosalicylate (LIS). Hybridization analysis was used to estimate the fraction of plasmid molecules remaining after nuclei were extracted. We examined the extent of matrix association of three ARSI plasmids, Trpl-RI circle (1.45 kb), YRp7 (5.7 kb) and pXBAT (45.1 kb) with mitotic loss rates ranging from 3–25%. In addition we examined the matrix binding of the endogenous 2 μm plasmid and the 2 μm-derived YEp 13 which is relatively stable in the presence of 2 μm and less stable in cir° strains. Among the ARS1 plasmids we observed a negative correlation between stability and matrix association, consistent with models in which binding to the nuclear matrix prevents passive segregation of ARS1 plasmid molecules. No such correlation was observed among the 2 μn plasmids. Among all plasmids examined there is a positive correlation between size and matrix association.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    ISSN: 1432-0983
    Keywords: Yeast ; Cloning ; ODC ; Complementation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A DNA fragment containing the gene encoding orotidine 5′-phosphate decarboxylase (ODC) from the yeast, Schwanniomyces occidentalis (formerly castellii) has been isolated from a genomic library constructed in the S. cerevisiae expression vector, pYcDE8. A recombinant plasmid, p2-lA, containing a 2.47 kb insert was shown to complement the ura3-52 mutation of several strains of S. cerevisiae. This DNA insert was shown to be from Schwanniomyces occidentalis by Southern hybridization analysis. A restriction enzyme cleavage map of the insert has been derived and the ODC gene localized to a 1.1 kb region by deletion analysis. In addition, we have demonstrated that expression of ODC is not dependent on the ADHI promoter carried on pYcDE8. This is the first report of the cloning of a gene from a member of the genus Schwanniomyces.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Site specific recombination ; 2 μ DNA plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The purpose of this work is to identify and quantitate in vivo 2 μ plasmid FLP-independent recombination in yeast, using a nonselective assay system for rapid detection of phenotypic expression of the recombination events. A tester plasmid was constructed such that in vivo recombination between 2 μ direct repeat sequences produces the resolution of the plasmid into two circular DNA molecules. This recombinational event is detected as a phenotypic shift from red to white colonies, due to the mitotic loss of the plasmid portion containing the yeast ADE8 gene in a recipient ade1 ade2 ade8 genetic background. In the absence of the 2 μ FLP recombinase and/or its target DNA sequence, recombination is not abolished but rather continues at a high frequency of about 17%. This suggests that the FLP-independent events are mediated by the chromosomally-encoded general homologous recombination system. We therefore conclude that the totality of 2 μ DNA recombination events occurring in FLP+ cells is the contribution of both FLP-mediated and FLP-independent events.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 1432-0983
    Keywords: Schizosaccharomyces pombe ; Saccharomyces cerevisiae ; Argininosuccinate lyase ; Gene cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A gene bank of Sau3A partially restricted Schizosaccharomyces pombe DNA in YEp13 was used to transform an arg4 mutant of Saccharomyces cerevisiae. One colony was recovered which contained the YEp13 plasmid bearing a large insert complementing the argininosuccinate lyase (ASL) mutation. As shown by restriction mapping and subcloning experiments, the DNA sequence required for complementation is localized on a 2 kb BamHI-BamHI fragment. The plasmid complemented several S. cerevisiae arg4 mutants of independent origin and a S. pombe arg7 mutant lacking ASL. Low but significant ASL activities were detected in crude extracts of these transformants. No complementation of the E. coli argH mutant was observed. Southern blot hybridizations showed that the insert originates from the S. pombe genome. No cross-hybridization was found between this sequence and S. cerevisiae DNA. It can be concluded that the cloned DNA fragment bears the S. pombe ARG7 gene coding for ASL.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 14 (1988), S. 413-418 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Chromosome length polymorphisms ; FIGE ; OFAGE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Although Saccharomyces cerevisiae strains generally have similar chromosomal band patterns as revealed by pulsed field gel electrophoresis, individual bands often move slightly differently from one strain to the other. Surveying strains from our stock collection, we found that nearly all the bands of a certain pair of strains differed in their mobility. Some of these chromosome length polymorphisms segregated in a 2:2 ratio, indicating that they resulted from single structural alterations (i.e. additions or deletions). One of these was mapped on the right arm of chromosome 1. Others did not segrate in a simple 2:2 ratio. That is, there were progenies which had bands not present in either parent. We suggest that these new bands are the products of recombination between homologous chromosomes having two or more structural alterations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 14 (1988), S. 163-170 
    ISSN: 1432-0983
    Keywords: Plant mtDNA ; Electron microscopy ; Restriction enzymes ; Hairpin structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Broad bean (Vicia faba) mitochondrial DNA (mtDNA) includes three circular plasmids: mt-plasmid 1 (1,704 ntp), mt-plasmid 2 (1,695 ntp) and mt-plasmid 3 (1,476 ntp). Partially replicated circular forms of these mt-plasmids have been observed in electron microscope preparations. Restriction enzymes that cleave either mt-plasmid 2 (but not mt-plasmids 1 and 3) or mt-plasmid 3 (but not mt-plasmids 1 and 2) were used to generate linear forms of partially replicated mt-plasmid 2 and mt-plasmid 3 molecules. Analyses of these linearized replicative intermediates, observed by electron microscopy, indicated that in both mt-plasmid 2 and mt-plasmid 3 replication originates at a specific location and proceeds in the same, single direction around the molecules. The replication origins of mt-plasmid 2 and mt-plasmid 3 map close to sequences that can fold into hairpin structures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1432-0983
    Keywords: ARS ; Saccharomyces cerevisiae ; Schizosaccharomyces pombe ; Tetrahymena thermophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have isolated several Tetrahymena thermophila chromosomal DNA fragments which function as autonomously replicating sequences (ARS) in the heterologous Saccharomyces cerevisiae and Schizosaccharomyces pombe selection systems. The Tetrahymena ARS sequences were first isolated in S. cerevisiae and were derived from non-ribosomal micro- and macronuclear DNA. Sequence analysis of the ARS elements identified either perfect or close matches with the 11 by S. cerevisiae ARS core consensus sequence. Subcloning studies of two Tetrahymena ARS elements defined functional regions ranging in size from 50 to 300 bp. Testing of the ARS elements in S. pombe revealed that most of the T. thermophila inserts confer ARS function in both yeasts, at least in the sense of promoting a high transformation frequency to plasmids which contain them. However, the actual sequences responsible for ARS activity were not always identical in the two yeasts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Ribosomal protein genes ; CYH2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A diploid strain of the yeast Saccharomyces cerevisiae has been constructed that has one copy of the ribosomal protein gene CYH2 completely deleted and replaced with the TRP1 gene using the method of Rothstein (1983). There are only small differences in growth rate and no detectable difference in steady state level of CYH2 mRNA between the diploid that is heterozygous for the CYH2 deletion and the parent diploid with two normal copies of this gene. This suggests that the diploid must partially compensate for the loss of one CYH2 gene. Tetrad dissection shows that haploid spores lacking the CYH2 gene cannot germinate. The lethality of this deletion can be rescued by a CYH2 cDNA on a low copy vector. Haploids which lack the genomic copy of the CYH2 gene, but contain a plasmid copy of the CYH2 cDNA are able to grow normally. These CYH2 deleted yeast haploids should be useful to analyze mutationally altered CYH2 genes and genes homologous to CYH2 from other organisms without interference from a genomic copy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1432-0983
    Keywords: Yeast ; Gene regulation ; Saccharomyces cerevisiae ; PDCI promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 870 by promoter fragment of the PDC1 gene that includes the carbon source dependent regulatory regions was investigated using 5′ and 3′ promoter deletions. The results indicate that glucose and ethanol regulation of PDC1 transcription are independently controlled by distinct cis-acting regions. The consensus sequence AAATCGATA may play a role in this regulation, while the sequence (ATCA)AACCT may be important in transcription initiation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1432-0983
    Keywords: Gene regulation ; Cell cycle ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Expression of the thymidylate synthase gene (TMPI) of Saccharomyces cerevisiae increases during the late G1 phase of the cell cycle. Using a series of gene fusions, which have placed the Escherichia coli lacZ gene under transcriptional and translational control of different portions of the TMPI gene, we have demonstrated the existence of three different regions which are important for expression. One of these regions, which was localized to within 270 base pairs of the translation start codon, is involved in the periodic expression of TMPI transcript. A second region, the deletion of which resulted in reduced levels of TMPI expression, is at least partially encoded by DNA sequences between 270 and 377 base pairs upstream of the translation start codon. A third region, located within the N-terminal 112 codons of the TMPI gene, apparently encodes information involved in a post-translational control mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1432-0983
    Keywords: Yeast ; Minichromosomes ; Impaired segregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nondisjunction of artificial yeast minichromosomes (2:0 segregation events) during mitosis is accompanied by the appearance of cells containing more than one copy of the mini-chromosome. A mathematical simulation of this process has demonstrated that under certain conditions, a nondisjunction of the minichromosomes may result in their accumulation in a considerable portion of the cell population. An increase in the copy number of artificial minichromosomes as a result of impaired segregation has been used to develop a new experimental procedure for directly selecting yeast mutants showing an impaired segregation of artificial minichromosomes during mitosis. Four new genes, AMC1, AMC2, AMC3, and AMC4, which control the segregation of artificial minichromosomes in mitosis, have been identified (AMC-3 and AMC4 are mapped to chromosome IV and VII, respectively). Mutations in the genes AMC1–AMC4 also affect the mitotic transmission of natural chromosomes. We suggest that the genes AMC1, AMC2, AMC3, and AMC4 control the segregation of natural chromosomes in yeast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1432-0983
    Keywords: Yeast ; Diuron ; Respiration ; Nuclear genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae, diuron blocks the respiration pathway at the level of the bc1 complex. Nuclear diuron-resistant mutations which confer in vitro resistance to mitochondrial NADH oxidase have been identified. Five mutations were found to be clustered at two distinct nuclear loci, DIU3 and DIU4. The distance between the two loci was estimated to be about 36.7 cM. These loci do not appear to be centromere-linked and did not show a linkage to any of the genes coding for bc1 complex subunits. DIU3 and DIU4 loci might, therefore, code for other components of the respiratory chain.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1432-0983
    Keywords: Alcoholic fermentation ; Deletion mutant ; Pyruvate decarboxylase ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We deleted most of the pyruvate decarboxylase structural gene PDC1 from the genome of Saccharomyces cerevisiae. Surprisingly, mutants carrying this deletion allele showed a completely different phenotype than previously described point mutations. They were able to ferment glucose and their specific pyruvate decarboxylase activity was only reduced to 45% of the wild type level. Northern blot analysis revealed that a sequence in the yeast genome homologous to PDC1 and formerly designated as a possible pseudogene is expressed and may code for a different but closely related pyruvate decarboxylase. The products of the two PDC genes seem to form hybrid oligomers, however both homooligomers have enzyme activity. Thus, the product of the PDC1 gene is not absolutely neccessary for glucose fermentation in yeast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Vector ; Glyphosate resistance ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The E. coli aroA gene was inserted between yeast promoter and terminator sequences in different shuttle expression plasmids and found to confer enhanced EPSP synthase activity as well as resistance to glyphosate toxicity. Subsequently, a transformation system using these newly constructed vectors in yeast was characterized. The efficiency of the glyphosate resistance marker for transformation and selection with plasmid pHR6/20-1 in S. cerevisiae laboratory strain SHY2 was found to be relatively high when compared with selection for LEU2 prototrophy. The fate of the recombinant plasmid pHR6/20-1 in the transformants, the preservation of the aroA E. coli DNA fragment in yeast, mitotic stability, EPSP synthase activity, and growth on glyphosate-containing medium have been investigated. As this plasmid also allows direct selection for glyphosate resistant transformants on rich media, the glyphosate resistance marker was used for transforming both S. cerevisiae laboratory strain SHY2 and brewer's yeast strains S. cerevisiae var. “uvarum” BHS5 and BHS2. In all cases, the vector pHR6/20-1 was maintained as an autonomously replicating plasmid. The resistance marker is, therefore, suitable for transforming genetically unlabeled S. cerevisiae laboratory, wild, and industrial yeast strains.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    ISSN: 1432-0983
    Keywords: Yeast ; 2μm FRT duplication ; Intrachromosomal recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A YEp chimaeric plasmid carrying SMR1 and URA3 genetic markers was integrated into chromosome XIII at the ilv2-Δ1 locus in a [cir°] background. The 1.5 kb BglII deletion of ilv2-Δ1 allowed the clear identification of an integrant structure which consisted of a direct tandem duplication (TD) of the chimaeric plasmid. Within the integrant structure, a single copy of the plasmid sequence was flanked by a direct duplication of the 2μm site-specific recombinase (FLP) recognition target (FRT). Isogenic [cir°] and [cir +] diploids formed by crossing the [cir°] TD strain to complementary haploids were analyzed for plasmid marker loss and chromosomal DNA alterations in the presence and absence of selection pressure for the URA3 and SMR1 plasmid borne markers. [cir°] diploids showed no plasmid marker loss and maintained the TD structure. In the absence of selection pressure, the [cir +] diploid underwent FLP-FRT mediated unequal interchromatid recombination, resulting in the breakage-fusion-bridge cycle and homozygotization of chromosome XIII (Rank et al. 1988). Maintenance of selection pressure for the centromere distal plasmid URA3 marker selected against FLP-FRT interchromatid recombinants so that the effects of site specific recombinase on intrachromatid recombination could be evaluated. Intrachromatid recombination at the directly duplicated FRT sites of the TD structure resulted in the loss of a diagnostic internal fragment. These results show that in the presence of FLP, FRT sites separated by up to 13.3 kb of chromosomal DNA function as substrates for intra and interchromatid recombination.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1432-0983
    Keywords: Yeast ; Diuron ; Nuclear, mitochondrial mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae, diuron blocks the respiratory pathway at the level of the bc1 complex. Two mitochondrially inherited loci, DIU1 and DIU2, located in the cytochrome b gene, and two nuclearly inherited loci, DIU3 and DIU4, have previously been identified. The present work genetically characterizes two double mutants. One mutant, Diu-217, carries two nuclearly inherited mutations, diu3-217a and diu-217b; the second mutant, Diu-783, carries the previously described nuclear mutation diu3-783 and a mitochondrial mutation diu2-783. Each mutation, independent of its location, exhibits a weak diuron resistance. The joint expression of two or three mutations leads to a cumulative or a cooperative enhanced diuron-resistant phenotype.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial frameshift suppressor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A polypeptide chain-terminating mutation (M5631) previously has been shown to be a +1T insertion in the yeast mitochondrial gene oxi1, coding for subunit II of the cytochrome c oxidase. A spontaneously arisen frameshift suppressor (mfs-1) that is mitochondrially inherited suppresses this mutation to a considerable extent. The suppressor mutation was mapped by genetic and molecular analyses in the mitochondrial tRNASer-var1 region of the mitochondrial genome of the yeast S. cerevisiae. Genetic analyses show that the suppressor mfs-1 does not suppress other known mitochondrial frameshift mutations, or missense and nonsense mutations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein gene ; Transcription activation ; Mutation ; Methylation interference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Most ribosomal protein (rp-)genes in yeast are preceded by conserved sequence motifs that act as upstream transcription-activating sites (RPG box). These sequence elements have previously been shown to represent specific binding sites for a protein factor, TUF. Comparison of the various nucleotide elements identified so far indicates a remarkably high degree of variation in the respective sequences. On the other hand, a methylation interference study performed with one RPG box revealed close contact points with the TUF protein along the entire sequence. To investigate the sequence requirements of the RPG box, we inserted synthetic oligonucleotides that differed from the general consensus sequence ACACCCATACATTT at single positions into a deletion mutant of the L25 promoter that lacked its natural RPG elements. Transcription activity was estimated by Northern analyses of the cellular level of L25-galK hybrid transcripts. The results show that in the 3′ part of this sequence element single substitutions are allowed at all positions, in the 5′ part, however, the nucleotide requirements appear to be more stringent. In particular, the invariant C at position 5 of the consensus sequence is absolutely necessary for its enhancer function.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    ISSN: 1432-0983
    Keywords: Yeast ; oxi3 gene ; Petite genome ; Frameshift mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sequence analysis was used to define the repeat unit that constitutes the mitochondrial genome of a petite (rho −) mutant of the yeast Saccharomyces cerevisiae. This mutant has retained and amplified in tandem a 2,547 by segment encompassing the second exon of the oxi3 gene excised from wild-type mtDNA between two direct repeats of 11 nucleotides. The identity of the mtDNA segment retained in this petite has recently been questioned (van der Veen et al., 1988). The results presented here confirm the identity of this mtDNA segment to be that determined previously by restriction mapping (Carignani et al., 1983).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Chromosome V ; Ty elements ; tRNA genes ; Transposition hot-spots ; Yeast polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ty4 is a novel transposable element in the yeast, Saccharomyces cerevisiae, which is present in only a few copies in the genome (Stucka et al. 1989). In strain C836 one of the three copies (Ty4-90) is contained in cosmid clone c90, where it resides on chromosome V. Analysis of this region reveals a “hot-spot” of transposition: in addition to Ty4-90, the locus contains a complete Ty3 element and seven singular delta, sigma and tau elements. Three tRNA genes (for His, Lys, and Ile) are located in this region, and these are closely associated with one or the other of the elements, a phenomenon commonly observed in yeast. A comparison of c90 with corresponding regions from other strains shows that the locus is highly polymorphic and that this polymorphism is explicitly associated with Ty transposition and recombination events.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosome synthesis ; Regulation ; Ribosomal protein turnover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When the gene dosage for the primary rRNA-binding ribosomal protein L25 in yeast cells was raised about 50-fold, the level of mature L25 transcripts was found to increase almost proportionally. The plasmid-derived L25 transcripts were structurally indistinguishable from their genomic counterparts, freely entered polysomes in vivo and were fully translatable in a heterologous in vitro system. Nevertheless, pulse-labelling for periods varying from 3–20 min did not reveal a significant elevation of the intracellular level of L25 protein. When pulse-times were decreased to 10–45 s, however, we did detect a substantial over production of L25. We conclude that, despite the strong RNA-binding capacity of the protein, accumulation of L25 is not controlled by an autogenous (pre-)mRNA-targeted mechanism similar to that operating in bacteria, but rather by extremely rapid degradation of excess protein produced.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1986), S. 943-945 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; α-factor ; Protoplasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When Mat a cells are treated with α-factor prior to being protoplasted and fused, the frequency of karyogamy is higher than in unarrested controls.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1985), S. 87-93 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; oxi2 mutations ; Functional suppressors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A semidominant nuclear suppressor, callednam6, ofoxi2-V276 mitochondrial mutation has been isolated and characterized. The nuclear character ofnam6 was proved by its retention inrho° strains, lack of mitotic segregation in diploids and meiotic 2:2 segregation in tetrads. The specificity ofnam6 was tested on 315mit − mutations of four mitochondrial genes (oxi1, oxi2, oxi3, andcob-box). It suppresses clearly only three mutations in theoxi2 gene, restoring partially or completely cytochrome aa3 formation. The results suggest a functional character of the suppression.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1432-0983
    Keywords: Sporulation ; Yeast ; Transcription ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have characterized 46 hybrid phage which hybridize preferentially to mRNA from sporulating cells. Cross-hybridization experiments demonstrate that 27 distinct SPR (Sporulation regulated) sequences are represented among these phage. The SPR genes can be grouped into three classes: early, middle, and late. The early class shows an accumulation of transcripts soon after transfer to sporulation medium and continues to accumulate RNA throughout sporulation. Transcripts of the middle class increase in level at about the time of DNA synthesis, rise rapidly in abundance until meiosis II, then accumulate more slowly for at least the next 3 h. Late gene transcripts begin to accumulate at about the time of meiosis I, increase 10- to 20-fold in the next 2 h, then remain constant in late sporulating cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1985), S. 179-185 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Resistance ; Mercury ; Tyrosine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary From a cross of two strains ofSaccharomyces cerevisiae, both of which had the same (wild type or normal) level of resistance to inorganic mercury, segregants having three distinguishable resistance levels, normal, sensitive and semi-sensitive, were obtained. Genetic analyses of the parents and the progeny indicated that the levels of inorganic mercury sensitivity were determined by three distinct loci,HGS1, HGS2 andMSM1. The recessive allele of theHGS1 locus,hgsl-1, and the codominant allele of theHGS2 locus,HGS2-1, were necessary for the sensitive phenotypes, and alleles in theMSM1 locus,MSMI-1 andmsml-2, were responsible for the different sensitivity levels. In short, the strains of genotypeshgs1-1 HGS2-1 msml-2 andhgsl-1 HGS2-1 MSMI-1 were sensitive and semi-sensitive, respectively, while the strains of all other genotypes were normal. Although thehgs1-1 allele was identified as thearo7-1 mutation which confers deficiency of tyrosine and phenylalanine, mutations such asaro1B (deficiency of tyrosine, phenylalanine and tryptophan) andtyr1 (deficiency of tyrosine) had similar effects asaro7-1 on inorganic mercury sensitivity. From these results we conclude that theHGS2-1 allele causes inorganic mercury sensitivity when the cells are defective in the tyrosine biosynthesis. In fact, addition of tyrosine to the growth medium containing inorganic mercury resulted in increase of colony forming ability of the sensitive strains.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1986), S. 665-670 
    ISSN: 1432-0983
    Keywords: Multiple drug resistance ; Genetic mapping ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the yeast Saccharomyces cerevisiae, two nuclear pleiotropic drug resistance mutations pdr3-1 (former designation muc PR) and pdr3-2 (former designation DRI9/T7) have been selected as resistant to mucidin and as resistant to chloramphenicol plus cycloheximide, respectively. The pdr3 mutations were found not to affect the plasma membrane ATPase activity measured in a crude membrane fraction. Meiotic mapping using strains with standard genetic markers revealed that mutation pdr3-1 is centromere linked on the left arm of chromosome II at a distance of 5.9 ± 3.3 cM from its centromere and 11.6 ± 3.1 cM from the marker pet9. The centromere linked pdr3-2 mutation exhibited also genetic linkage to pet9 with a map distance of 9.8 ± 3.2 cM. These results indicate that pdr3-1 and pdr3-2 are alleles of the same pleiotropic drug resistance locus PDR3 which is involved in the control of the plasma membrane permeability in yeast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 10 (1986), S. 657-664 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Amino acid biosynthesis ; General control ; GCD-genes ; GCN-genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutant strains, resistant against the amino acid analogues 5-methyltryptophan, 5-fluorotryptophan and canavanine were isolated, starting with a trp2 leaky auxotrophic strain. Of 10 such strains, only four turned out to be of the “general control derepressed” (gcd) mutant type. Three other isolates were shown to be defective in the general amino acid permease system, while the remaining three strains displayed low spore viability and were not further investigated. Complementation tests amongst the four new gcd-mutant strains, including strain RH558 gcd2-1 isolated earlier, yielded five complementation groups: GCD2, GCD3, GCD4, GCD5, and GCD6. All mutant strains showed a dual phenotype, which was not separable by wild type backcrosses: “constitutive derepression” and “slow growth”. Epistatis of all gcd mutations over gcn1-1, gcn2-1 and gcn3-1 was found with respect to both phenotypes, except for gcd5-1, which was lethal in these combinations. On the other hand gcn4-101 was found to be epistatic over all gcd mutations, but only with respect to the “constitutive derepression” phenotype, and not to “slow growth”; again the combination with gcd5-1 was lethal. Mutation gcd2-1 was mapped on chromosome VII, 50 cM from leu1 and 22 cM from ade6. A new model is discussed, in which GCD-genes are involved in the amino acid uptake into the vacuoles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1432-0983
    Keywords: Sugar beet ; Cytoplasmic male sterility ; Mitochondrial DNA ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitochondrial (mt) DNAs from normal (N) and male sterile (S) cytoplasms of sugar been have been isolated and investigated by electron microscopy. The results showed that mtDNA was composed of a heterogeneous population of circular molecules. Their contour lengths varied from 0.28 to 51 μm, but unlike in the case of maize, a large difference was not observed in the distribution of molecular classes greater than 1.0 μm between N and S cytoplasms of sugar beet. On the other hand, N and S cytoplasms were shown to contain their own characteristic combinations of small circular mtDNA species with lengths between 0.28 μm and 0.6 μm. Mitochondrial DNAs from various sources of male-sterile cytoplasms were analyzed by agarose gel electrophoresis to determine the extent of cytoplasmic variation. Additional low molecular weight DNA bands appeared in all male-sterile lines examined, and as a result, three distinctive banding patterns were recognized. These data are in general agreement with those based upon restriction endonuclease digestion of mt and chloroplast DNAs and the genetic analysis of fertility restoration in test crosses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Inducible repair ; Plasmid transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many reports show that resistance of Saccharomyces cerevisiae to a large UV dose can be enhanced by pre-induction with a smaller one given some hours before. This work tests if such increased cell survival is associated with increased DNA repair on UV damaged plasmid transformed into yeast. There was no change in transformation efficiency of UV-damaged plasmid DNA under conditions where RAD cell survival increased 5-fold, and where rad1-1 and rad6-1 survival increased 2-fold. It is concluded that DNA repair activity involving the RAD6 and RAD3 pathways is either not inducible or is unable to work on plasmid DNA. It is suggested that the enhancement of cellular survival detected may be based on changes in cell-cycle behaviour which permit cells generally proficient in repair a greater chance to recover.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    ISSN: 1432-0983
    Keywords: Tetrahymena ; Replication ; Segregation ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously demonstrated that a 657 bp TaqI-XbaI and a 427 by XbaI-XbaI fragment from the 5′ non-transcribed spacer of the extrachromosomal ribosomal DNA of Tetrahymena thermophila function as autonomously replicating sequences (ARS) in Saccharomyces cerevisiae. These fragments are adjacent to each other in a region that encompasses the in vivo origin of bidirectional replication of rDNA. The presence of a yeast centromere (CEN) fragment does not confer mitotic stability on these plasmids. A sensitive yeast colony colour assay (Hieter et al. 1985a) has been used to evaluate the cis-acting effect of each ARS segment on the pattern of inheritance of a plasmid containing CEN5:URA3:SUP4. Colonies of transformed cells obtained both in the presence and absence of selection were red with no detectable white or pink sectors. The lack of sectoring indicates that both plasmids are lost at an extremely high rate, likely due to 1:0 segregation events. We conclude that while these ARS elements confer a high frequency transformation phenotype, they lack a function which is required in cis for the maintenance of mitotic stability in the presence of a centromere. This missing cis-acting function may result in the inability of the plasmids to be brought under the control of cell-cycle regulated replication.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial ; Mutants ; RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is a description of a new class of temperature sensitive pet mutants in Saccharomyces cereviase that lose all or part of their mitochondrial RNA at the restrictive temperature. These mutants fall into 8 different complementation groups, mna1 to mna8, and 2 different classes based on their phenotype. Class I mutations, mna1-1 through mna5-1, cause complete or partial loss of mitochondrial RNA at the restrictive temperature. The mutation, mna1-1, is especially interesting since it causes a loss of both mitochondrial DNA and RNA when the mutant is grown on a fermentable carbon source at the restrictive temperature. However, when this mutant is grown at the permissive temperature on a non-fermentable carbon source then shifted to the restrictive temperature, only the mitochondrial RNA is lost. This indicates that the primary cause for the pet phenotype is due to the loss of mitochondrial RNA and not DNA. Class II mutations, mna6-1 through man8-1, cause complete loss of the 14S rRNA after growth at the restrictive temperature in a fermentable carbon source. This loss appears to be specific for the 14S rRNA, since all other transcripts probed by Northern analysis are normal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    ISSN: 1432-0983
    Keywords: Yeast ; Disomy for chromosome IV ; Mitochondrial rho − mutability ; Mitotic chromosome loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The disomy for chromosome IV in the strains studied led to: i) a reduction in the red pigmentation of ade1 mutant colonies; ii) a decrease of the spontaneous rho − mutant frequency, and iii) an impairment of sporulation in hybrids descended from disomic parents. The nuclear srm1 mutation decreasing the spontaneous rho − mutability promoted the spontaneous extra chromosome loss in the disomes for chromosome IV. This result suggests a close connexion between the spontaneous rho − mutability and mitotic chromosome stability.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    ISSN: 1432-0983
    Keywords: Y. lipolytica ; LEU2 ; Yeast ; Leucine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 2810 by DNA fragment containing the beta-isopropylmalate dehydrogenase gene of the dimorphic yeast Yarrowia lipolytica has been sequenced. The sequence contains an open reading frame of 405 codons, predicting a protein of 43,366 molecular weight. Protein sequence homology with the polypeptide encoded by the LEU2 gene of Saccharomyces cerevisiae is 64%, whereas DNA sequence homology is 61%. The 5′- and 3′-flanking regions of the Y. lipolytica LEU2 gene share only some general structural features common to genes of S. cereviside such as the presence and location of TATA boxes, CAAT boxes, CACACA repeats, the lack of G residues in the 5′-untranslated region and 3′-transcription terminators. Transcription of a 1.4 kb mRNA begins at a small cluster of sites approximately 40 base pairs before the initial ATG.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 11 (1987), S. 411-413 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial rho − mutability ; Genetic analysis ; Modifying genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The phenotypic trait “starry colony” in Saccharomyces is associated with a high spontaneous rho − petite mutability. Genetic analysis of this trait has shown the high rho − mutability to be caused by several modifying genes present together in the strains studied. Every single modifying gene produces only a relatively small enhancement of the rho − mutability.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; 2 μ plasmids ; Plasmid free segregants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The maximum specific growth rates (μmax) of 2 μ-plasmid-free ([cir°]) segregants of three haploid and one diploid strain of Saccharomyces cerevisiae have been determined and compared with the μmax of their 2 μ-plasmid-containing ([cir +]) progenitors. Two classes of [cir°] strains have been examined: those induced by transformation with a 2 μ-based recombinant plasmid according to the method of Dobson et al. (1980) and those isolated as spontaneous [cir°] segregants from glucose-limited continuous cultures. The μmax of the spontaneous [cir°] segregants was not found to differ significantly from that of their [cir +] parents. In all cases, however, the induced [cir°] strains had a μmax which was significantly less than that of their [cir +] counterparts. This effect was particularly marked in the case of the diploid strain where a 34% reduction in μmax was observed. The implications of these results are discussed in terms of the effect of the transformation process on host yeast cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 1432-0983
    Keywords: Yeast ; Mutagenesis ; Base analogues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of the yeast, Saccharomyces cerevisiae, which are auxotrophic for thymidylate (tmp1) can also incorporate analogues of thymidylate. When the base analogue, 5-bromodeoxyuridylate, is incorporated into tmp1 yeast cells it is lethal and mutagenic. Both lethality and mutation induction can be drastically altered by perturbation of the pyrimidine nucleotide pools. Analysis of mutation induction, bromodeoxyuridylate incorporation into DNA, and cell viability under various conditions revealed: (1) lethality and mutagenesis can be uncoupled, (2) thymidylate enhances mutagenesis and deoxycytidylate suppresses it, (3) mutation induction is not correlated with the magnitude of bromodeoxyuridylate incorporation into DNA. Therefore, in yeast, the pyrimidine nucleotide pools have a powerful effect on bromodeoxyuridylate mutagenesis. Both bromodeoxyuridylate and iododeoxyuridylate are extensively incorporated into the DNA of tmp1 yeast cells; however, iododeoxyuridylate is non-mutagenic. Replication proceeds at the same rate in the presence of the natural substrate or either analogue. When cells are supplied with thymidylate and bromodeoxyuridylate together, there is no discrimination against bromodeoxyuridylate as a DNA precursor. However, in the presence of thymidylate and iododeoxyuridylate, there is a 3 to 1 discrimination against iododeoxyuridylate as compared to thymidylate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1432-0983
    Keywords: Kluyveromyces lactis ; Yeast ; Extrachromosomal inheritance ; Antimycin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Antimycin-resistant (AR) mutants of the yeast Kluyveromyces lactis, obtained either spontaneously or after manganese treatment, were isolated and genetically characterized. Most of the mutants obtained after manganese mutagenesis and two spontaneous mutants, tolerated high antimycin concentrations (more than 10 /gmg/ml) and were extrachromosomal. One mutant which grew only in low antimycin (1 /gmg/ml) showed a Mendelian type of inheritance. The extrachromosomal mutants could be assigned to at least two genetic loci (A I R and A II R ). Mutants representative of these two groups showed increased resistance to the antibiotic when the respiration of whole cells or mitochondria was studied. Extrachromosomal mutants of Saccharomyces cerevisiae resistant to antimycin were also induced with manganese, isolated and characterized. Comparative studies of the antimycin-resistant mutants of K. lactis and S. cerevisiae permitted the following observations: a) K. lactis is more resistant to antimycin, funiculosin, mucidin and diuron than S. cerevisiae, as are the AR mutants; b) K. lactis shows correlated sensitivity to funiculosin differing in this aspect from S. cerevisiae; c) the antimycin-resistant mutants of K. lactis belonging to group 11 (A II R ) were also resistant to diuron, tolerating concentrations of more than 200 /gmg/ml; d) all extrachromosomal antimycin-resistant-mutants of S. cerevisiae and some of the AR mutants of K. lactis were more sensitive to mucidin than the wild type.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; Translation ; Informational Suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phenotypic suppression by the antibiotic, paromomycin, of the mitochondrial oxi1 −-V25 mutation, a mutation which arrests by premature ochre codon the synthesis of the cox 11 subunit, was studied in isolated yeast mitochondria competent in translation. This antibiotic is known to suppress the mutation in vivo (Dujardin et al. 1984) and allowed in vitro, at concentrations of 20–1100 Mg per ml. the synthesis of the cox II subunit. This strongly suggests that phenotypic suppression of mit − mutations is due to the direct action of paromomycin on mitochondrial ribosomes. The effect of paromomycin bears a resemblance to the function of the omnipotent nuclear suppressor mutation R705. The nuclear suppression was expressed in isolated mitochondria; suppressor mutation influenced the structure of the mitoribosome. Therefore, it appears that mitoribosomes are indeed the common target in the phenotypical and genetic nuclear suppression of the oxi1-V25 mutation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Minor tRNAs ; Codon usage ; Transposable elements ; Delta ; Tau
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary During characterization of the whole tRNA(Glu) family from the yeast, Saccharomyces cerevisiae, we isolated one cosmid clone bearing a tRNA(Glu) gene copy that is deviant from the major tRNA(Glu3) gene members in only five positions. This divergent tRNA(Glu) is a minor species and is represented by a single gene copy. One of the nucleotide exchanges concerns the anticodon which is modified from T-T-C in the tRNA(Glu3) gene to C-T-C which implies that this tRNA serves the codon triplet G-A-G. Two other minor yeast tRNA species have been reported which appear to be particularly designed for the translation of those codons that have a G in its third (Wobble) position. The low abundance of such minor tRNA species correlates positively to the low occurrence of most of the N-N-G codons in yeast. Furthermore, the GAGtRNA(Glu) locus represents another case of the general phenomenon in which the majority of the tRNA genes in yeast are associated with one or several transposable elements forming complex patterns. In this particular case, divergent segments of delta and tau are present in the 5′ flanking region of the tRNA gene and arranged in a novel configuration. The sequence data lend support to the view that tau is not an evolutionary young element as was earlier anticipated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 16 (1989), S. 315-321 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Antisuppressor ; ADE3 ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutations in a known yeast gene, ADE3, were shown to act as an antisuppressor, reducing the efficiency of the omnipotent suppressor, sup45-2. The ADE3 locus encodes the trifunctional enzyme C1-tetrahydrofolate synthase, which is required for the biosynthesis of purines, thymidylate, methionine, histidine, pantothenic acid and formylmethionyl-tRNAfmet. The role of this enzyme in translational fidelity had not previously been suspected.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    ISSN: 1432-0983
    Keywords: Yeast ; Transcription ; RNA polymerase I ; Enhancer ; DNA-binding protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using the gel retardation assay we have identified a protein that can specifically bind to a site within the enhancer of the 37S pre-ribosomal RNA operon in yeast, as well as to a site 210 by upstream of the site of transcription initiation of this operon. This protein (RBP1) has been partially purified by means of heparin-agarose chromatography and protects 20 by in the rDNA enhancer, and 25 by in the initiation region, against DNase I in an in vitro footprinting assay. In vivo footprinting studies using methylation of intact yeast cells with dimethylsulphate, indicate that the same binding sites are occupied in vivo as well. Deletions that abolish binding of RBP1 to the enhancer in vitro, as well as linker insertions into the RBP1 binding site in the initiation region that strongly diminish in vitro binding of RBP1, have no effect whatsoever on the enhancement of rDNA transcription in vivo. This was studied by deletion/mutation of the RBP1 binding site in vitro in an artificial ribosomal minigene and measuring the effect on the minigene transcription in vivo in yeast cells, transformed with the deleted/mutated minigenes. It can therefore be concluded that binding of RBP1 is not an important parameter in the functioning of the rDNA enhancer in yeast. Using the same minigene system we also show that RBP1 is not involved in termination of RNA polymerase I (PolI) transcription at the main terminator T2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 1432-0983
    Keywords: Yeast ; Saccharomyces cerevisiae ; Nonsense suppression ; Omnipotent suppressors ; Gene mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ten dominant omnipotent suppressors of Saccharomyces cerevisiae, which were previously shown to be different from SUP46, have been examined. Nine are mapped in a region between lys5 and cyh2 on the left arm of chromosome VII. These suppressors, like SUP46, manifest sensitivity to increased temperature and the antibiotics paromomycin and hygromycin B. In addition, they have an identical action spectrum. These results strongly suggest that they are allelic to each other and they are designated SUP138. The tenth is mapped to a position between his1 and arg6 on the right arm of chromosome V. This suppressor, named SUP139, does not manifest temperature sensitivity nor antibiotic sensitivity. SUP139 and SUP138, which are clearly distinguished by means of action spectrum, act on much fewer nonsense mutations than SUP46. It is now clear that dominant omnipotent suppressors arising at a single locus are homogeneous and that their efficiency is locus-dependent. The order of efficiency is SUP46〉SUP138〉SUP139.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 16 (1989), S. 339-346 
    ISSN: 1432-0983
    Keywords: Yeast ; Transformation ; ss carrier DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A method, using LiAc to yield competent cells, is described that increased the efficiency of genetic transformation of intact cells of Saccharomyces cerevisiae to more than 1 × 105 transformants per microgram of vector DNA and to 1.5% transformants per viable cell. The use of single stranded, or heat denaturated double stranded, nucleic acids as carrier resulted in about a 100 fold higher frequency of transformation with plasmids containing the 2μm origin of replication. Single stranded DNA seems to be responsible for the effect since M13 single stranded DNA, as well as RNA, was effective. Boiled carrier DNA did not yield any increased transformation efficiency using spheroplast formation to induce DNA uptake, indicating a difference in the mechanism of transformation with the two methods.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 1432-0983
    Keywords: Platinum compounds ; Yeast ; Repair mutants ; Interstrand cross-links ; DNA degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four haploid yeast strains differing in proficiency for DNA repair were treated with cis- or transDDP. The wild type was least sensitive while the excision-deficient mutants rad1, rad2 and snm1exhibited higher sensitivities to either platinum compound. In all four strains tested cisDDP showed a two- to five-fold higher cytotoxicity than equimolar concentrations of transDDP. DNA interstrand cross-linking was caused by both agents in all strains. However, transDDP introduced more DNA cross-links at exposure times up to 6 h while cisDDP was the more active cross-linking agent at longer times. There was no clear-cut correlation of the number of DNA interstrand cross-links with survival. Formaldehyde-treated cells showed DNA with lower buoyant density due to proteinase K sensitive DNA-protein cross-linking; this effect was not observed after treatment with either platinum compound. Post-treatment incubation of wild-type cells exposed to cisDDP led to degradation of DNA by single and double-strand breaks, parallel with further increase of DNA interstrand cross-linking. DNA from transDDP-treated cells did not show extensive degradation although interstrand cross-links were lost during liquid holding.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 16 (1989), S. 347-350 
    ISSN: 1432-0983
    Keywords: Yeast ; 7SL RNA ; Yarrowia lipolytica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have identified an abundant cytoplasmic 7S RNA in crude extracts of the yeast Yarrowia lipolytica. A cDNA probe was prepared from this RNA and used to screen a genomic library. The DNA sequence of a positive clone was determined and the end positions of the 7S RNA gene established by comparison with the sequence of the extremities of 7S RNA. This gene, designated SCR2, encodes a 270-nucleotide RNA that can be folded into a secondary structure similar to that of 7SL RNAs. This RNA is 94.4% homologous to a previously identified 7S RNA from this yeast, but is encoded by a separate gene with highly divergent flanking sequences.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 1432-0983
    Keywords: Yeast ; ARS-like activity ; Petite genome replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seven MboI fragments spanning the mitochondrial apocytochrome b gene in Saccharomyces cerevisiae strain D273-10B were cloned in the BamHI site of the integrative yeast vector YIp5 and the capacity for autonomous replication was subsequently assayed in yeast. The positive correlation found between the ars-like activity in four fragments and the presence of regions common to multiple ethidium bromide-induced petite (rho−) genomes suggests that the mitochondrial sequences possibly active as origins of replication in low-complexity neutral or weakly suppressive rho− mutants could be functionally related to the yeast nuclear replicator 11 nucleotide motif defined by Broach et al. (1983).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 13 (1988), S. 21-23 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Transformation ; Plasmid ; Colony ; Polyethylene glycol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A rapid and simple yeast transformation procedure has been developed using colonies on agar plates. Saccharomyces cerevisiae SHY3 cells were picked up from colonies on YPD plates grown freshly or stored at 4 °C and incubated with M13RK9-T DNA at 30 °C for 1–2 h in a solution of Li+, Ca2+, Mg2+, triacetin and polyethylene glycol. About 3,500 transformants were obtained per µg of double stranded M13RK9-T DNA. Unlike the existing spheroplast techniques, single stranded M13RK9-T DNA transformed intact cells below one-hundredth frequency of the duplex form.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 13 (1988), S. 455-460 
    ISSN: 1432-0983
    Keywords: Yeast ; Gene conversion and mutation ; CDC8 locus ; Cell cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The induction of mitotic recombination in theCDC8 locus was studied in a diploid strain heteroallelic forcdc8 mutations (cdc8-1/cdc8-3); mitotic reversion was studied in strainscdc8-1/cdc8-1 andcdc8-3/cdc8-3. Conversion and reversion did not occur in those cells blocked at the S stage of the cell cycle by exposure to a nonpermissive temperature. In stationary phase cells irradiated just prior to exposure to temperature stress, the induction of recombinants was rather low and the induction of revertants was minimal. Conversely, a significant induction ofcdc + occurred in logarithmic phase cells subjected to the same treatment. Irradiation of synchronously dividing cultures revealed that intragenic recombination occurs at all three stages of the cell cycle- G1, S and G2. It was also found that UV-induced gene reversion can occur during the S and G2 stages, but not during the G1 stage of the cell cycle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 1432-0983
    Keywords: Aspergillus terreus clonotheque ; Saccharomyces cerevisiae ; Homologous integration ; 2 μ circledirected chromosome destabilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A genome clonotheque consisting of 25- to 40-kb Sau3A1 fragments of Aspergillus terreus DNA was constructed in the episomal cosmid vector pES33 containing the yeastARG4 gene. From the 475 transformants of cir° yeast strain ESH-0, 23 stable Arg + transformants were independently selected. Genetic and Southern analysis of these stable transformants showed that 39% arose as a result of recombination between cloned A. terreus DNA sequences and yeast chromosome XII. The recombination events most likely occurred in the regions of homology within the rDNA clusters of A. terreus and Saccharomyces cerevisiae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    ISSN: 1432-0983
    Keywords: Yeast ; Repair ; Complementation ; Saccharomyces cerevisiae ; Schizosaccharomyces pombe ; Gene cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two Saccharomyces cerevisiae genes necessary for excision repair of UV damage in DNA, RAD1 and RAD2, were introduced individually, on a yeast shuttle vector, into seven Schizosaccharomyces pombe mutants — rads1, 2, 5, 13, 15,16 and 17. The presence of the cloned RAD1 gene did not affect survival of any of the S. pombe mutants. The RAD2 gene increased survival of S. pombe rad13 to near the wild-type level after UV irradiation and had no effect on any of the other mutants tested. S. pombe rad13 mutants are somewhat defective in removal of pyrimidine dimers so complementation by the S. cerevisiae RAD2 gene suggests that the genes may code for equivalent proteins in the two yeasts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1432-0983
    Keywords: DNA transformation ; Saccharomyces cerevisiae ; Site-specific recombination ; 2μ DNA plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 2μ DNA plasmid of the yeast Saccharomyces cerevisiae does not confer any known selectable phenotype to the host cell carrying it. Selection of cells transformed with purified 2μ DNA therefore cannot be achieved, and the intracellular presence of 2μ can only be assessed by molecular analysis of the DNA complement. In addition, 2μ alone does not replicate in bacterial hosts, thus rendering its amplification by conventional methods impossible. We have isolated a shuttle plasmid, pBH-2L, generated by in vivo sites-pecific recombination between the endogenous 2μ DNA plasmid and pRL, a pBR322 derivative containing the yeast LEU2 gene and one 2μ repeat sequence associated with the origin of replication. This new shuttle plasmid has the property, when transformed into yeast, of undergoing site-specific recombinational resolution between its two direct repeat sequences. This releases 2μ plasmid and pRL as individual molecules. The latter can undergo progressive mitotic loss during growth in nonselective medium, ultimately leaving leucine auxotrophic transformants that contain only 2μ DNA plasmid. This system can be utilized to introduce 2μ DNA alone into cells lacking it, thereby providing a novel means to study the biology and the molecular genetics of the plasmid and its potential practical applications as a vector.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 15 (1989), S. 99-106 
    ISSN: 1432-0983
    Keywords: Yeast ; Isoleucyl-tRNA synthetase ; Isoleucine ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The isoleucyl-tRNA synthetase gene (ILS1) from the yeast Saccharomyces cerevisiae was cloned and sequenced. This gene was initially cloned because it cross-hybridizated to what is now presumed to be the isoleucyl-tRNA synthetase gene (cupC) from the protozoan Tetrahymena hhermophila. The ILS1 gene was determined to be 1,072 amino acids in length. A comparison with a recently published sequence of ILS1 1 from another laboratory (Englisch et al. 1987) was made and differences noted. Two promoter elements were detected, one for general amino acid control and one for constitutive transcription. A heat shock protein (hsp70) gene (probably SSA3) was found 237 by upstream from the ILS1 translation start site. The ILS1 amino acid sequence was compared to isoleucyl-tRNA synthetases from other organisms, as well as to valyl-, leucyl- and methionyl-tRNA synthetases. Regions of conservation between these enzymes were found.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 15 (1989), S. 113-120 
    ISSN: 1432-0983
    Keywords: Calmodulin mutant ; Nuclear division ; Chromosome stability ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The coding region of a yeast calmodulin gene was fused to a galactose-inducible GAL1 promoter, and a conditional-lethal mutant of Saccharomyces cerevisiae, in which the expression of calmodulin was regulated by galactose, was constructed. The mutant grew normally in galactose medium, but in glucose medium, in which the promoter was repressed, it ceased growing after 12–15 h. The growth arrest was associated with a decrease in intracellular calmodulin levels: after 12h, no intracellular calmodulin protein was detectable. Analysis of the terminal phenotype showed that when the cell stopped growing, it had a bud, a nucleus after S-phase and a short mitotic spindle. Thus, the defect was mainly in nuclear division. Bud growth was partially inhibited in these cells: 27% of the cells stopped growing with a small bud. Furthermore, calmodulin-deficient cells showed elevated rates of chromosome loss, possibly as the result of a defect in the precise segregation of chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    ISSN: 1432-0983
    Keywords: PDC3 ; Pyruvate decarboxylase ; Subunits ; Yeast ; Cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Biochemical evidence that pyruvate decarboxylase in S. cerevisiae might be constituted from two independently encoded subunits led us to question genetic evidence for a single structural gene. The main evidence for this was that three “structural” mutations appeared to be alleles of the same gene, PDC1 (Schmitt and Zimmermann 1982). We report that one of these mutations (pdcl-30) is not allelic either to other pdc1 alleles or to pdc2 mutations and therefore is has been renamed pdc3-30 thus identifying a new gene, PDC3. We have cloned the PDC3 gene, it represents a unique sequence in the genome and targeted integration shows tight linkage to the PDC3 locus. However, the size, abundance and regulation of the PDC3 transcript suggest that it does not encode a second structural gene. Possible functions for the PDC3 gene product are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 15 (1989), S. 235-237 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondrial DNA ; Method of extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A rapid method for the extraction of yeast mitochondrial DNA (mtDNA) is described. In comparison with previous methods, it simplifies several steps, does not require either the isolation of mitochondria or phenol treatment and is less time consuming. This protocol gives a high yield of pure mtDNA (50–120 μg from a 100-ml culture), which can be directly used in various molecular applications: restriction enzyme digestion, electrophoresis, blotting, labeling, cloning and sequencing.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 16 (1989), S. 21-25 
    ISSN: 1432-0983
    Keywords: Yeast ; Vectors ; Stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have constructed a set of hybrid yeast Escherichia coli vectors which utilise the site specific recombination function of the Saccharomyces cerevisiae 2 μm plasmid to completely eliminate the bacterial moiety upon introduction into yeast. A number of these plasmids have been shown to exhibit high inheritable stability in both laboratory and industrial strains during non-selective growth. These plasmids are beneficial for the genetic modification of industrial yeast, particularly those used in the production of food and beverages, and are of benefit in the study of plasmid maintenance and heterologous gene expression.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mutagen hyperresistance ; Southern, Northern analysis ; Gene transplacement ; Transposon mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genes SNQ and SFA confer hyperresistance to 4-NQO and FA when present on a multi-copy plasmid in yeast. Both are non-essential genes since transplacement of SNQ by a disrupted snq-0::LEU2 yielded stable and viable haploid integrants. Southern analysis revealed that SNQ and SFA are single-loci genes, and OFAGE analysis showed that they are located on chromosome XIII and IV, respectively. Northern blot analysis of SNQ and SFA revealed poly(A)+ RNA transcripts of 2 kb and 1.7 kb, respectively. Nuclease S 1 mapping showed SNQ to have a coding region of 1.6 kb and SFA, one of 1.3 kb. The 5′ coding regions were determined for both genes, while the 3′ end could only be determined for gene SNQ. Both genes do not appear to contain introns. The SFA locus was also mapped by transposon mutagenesis. Tn10-LUK integrants disrupted the SFA gene function at sites that were determined by subcloning to lie within the SFA transcription unit.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; SKI3 ; SKI5 ; M1 dsRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have identified a mutant strain of the yeast Saccharomyces cerevisiae which overproduces killer toxin. This strain contains a single mutation which fails to complement defects in both the SKI3 and SKI5 genes, while a cloned copy of this gene complements both the ski3 and ski5 defects. The level of secreted toxin from a cDNA based plasmid is not increased in a ski3 strain, showing that the overproduction phenotype is dependent upon an increased level of M1 dsRNA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Psoralen photoaddition ; Interstrand cross-link ; Repair deficiency ; Genotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two different UVA irradiation systems were initially biologically calibrated with two haploid yeast strains proficient and deficient, respectively, in nucleotide excision repair. The number of DNA lesions introduced into the cell's genome by the photoactivated bifunctional furocoumarin 8-MOP was then calculated by means of the applied UVA exposure doses. At LD37 the repair-proficient wild type had about 14 ICL and 34 furan-side monoadducts in its DNA, while doubly blocked repair mutant rad3-12 pso1-1 had 2 ICL and 3 monoadducts. Locus-specific reversion of lys1-1 followed two-hit kinetics in the repair-proficient wild type and one-hit kinetics in an excision-deficient rad2-20 mutant, as would be expected if ICL was the main type of mutagenic lesion in the wild type and monoadducts the main mutagenic lesion type in the excision-deficient strain. Quantitative comparison of 8-MOP + UVA-induced ICL with those induced by bifunctional mustard revealed the former to have a much higher genotoxicity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    ISSN: 1432-0983
    Keywords: Yeast ; Chromosome organization ; Acid phosphatase ; Telomere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 17 kb region from near the right end of chromosome I of Saccharomyces cerevisiae was isolated on recombinant λ bacteriophages. This region contained the PH011 gene which was located only 3.4 kb from the right end of the chromosome. We found that this region also was repeated approximately 13 kb from the end of the chromosome VIII DNA molecule. The chromosome VIII sequence appears to be a previously unnamed acid phosphatase gene that we propose to call PH012. Thus, similar to the repeated SUC, MAL, X and Y' sequences, some members of the repeated acid phosphatase gene family also appear near the termini of yeast chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; Intron splicing ; RNA maturase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analyzed the expression and function of the intron-encoded bI4 maturase when frame-shift mutations in the upstream exon alter the translational process. By constructing secondary cis-acting mutations within the b14 intron, we observed (1) that the bI4 maturase is still translated in the presence of the upstream mutation, albeit in very low amounts, and (2) that the limited amounts of bI4 maturase made under these conditions is no longer able to promote the splicing process of the aI4 intron. These observations, which further strengthen the maturase model, strongly suggest that bI4 maturase acts sequentially on the bI4 intron and then on the aI4 intron.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...