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  • Immunocytochemistry  (149)
  • Lepidoptera  (146)
  • Yeast
  • Springer  (368)
  • American Institute of Physics
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  • 2005-2009
  • 1980-1984  (368)
  • 1945-1949
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 111 (1980), S. 355-363 
    ISSN: 1434-4475
    Keywords: Cerulenin ; Fatty acid donor ; Inositol deficiency ; Phospholipid biosynthesis ; Triacylglycerols ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Der Umsatz der Lipide vonSaccharomyces carlsbergensis ATCC 9080 wurde nach Vormarkierung mit3H-Ölsäure und14C-Palmitinsäure untersucht. Inositversorgte Zellen zeigen eine Verschiebung der Fettsäuren von den Triacylglycerinen in die Phospholipide, im besonderen in Phosphatidylcholin und Phosphatidylinosit. Eine verstärkte Übertragung der Fettsäuren von Triacylglycerinen auf Phospholipide konnte festgestellt werden, wenn vormarkierte Zellen auf ein Nährmedium, welches Cerulenin enthielt, übertragen wurde. Cerulenin inhibiert die Fettsäuresynthese und ruft in wachsenden Zellen Fettsäuremangel hervor. Inositdefiziente Hefezellen, welche einen erhöhten Triacylglycerinspiegel aufweisen, verwenden diese Triacylglycerine unter Fettsäuremangelbedingungen ebenfalls für die Synthese von Phospholipiden, besonders von Phosphatidylcholin, Phosphatidyläthanolamin und Phosphatidylserin. Da aus früheren Arbeiten bekannt ist, daß inSaccharomyces carlsbergensis praktisch keine β-Oxidation existiert, können die Triacylglyerine in diesem Hefestamm als Speicher für Fettsäuren angesehen werden, welche zur Synthese von Phospholipiden dienen.
    Notes: Abstract The turnover of lipids was studied in the yeast,Saccharomyces carlsbergensis ATCC 9080, after prelabeling of the cells with [3H] oleic acid and [14C] palmitic acid. In inositol supplemented cells, a redistribution of fatty acids from triacylglycerols to phospholipids (mainly phosphatidylcholine and phosphatidylinositol) could be demonstrated. An increased transfer of fatty acids from triacylglycerols to phospholipids was observed when prelabeled cells were transferred to a growth medium containing cerulenin, which inhibits fatty acid synthesis and thus induces fatty acid deficiency in the growing cells. Inositol deficient cells contain increased levels of triacylglycerols, which are equally well utilized for phospholipid (mainly phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine) synthesis under conditions of fatty acid deficiency. The present results together with the previous finding that β-oxidation is practically absent inSaccharomyces carlsbergensis suggest that in this yeast triacylglycerols function as storage of fatty acids which can be mobilized for phospholipid biosynthesis.
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  • 2
    ISSN: 1570-7458
    Keywords: host-plant relations ; host variation ; Malacosoma americanum ; Malacosoma disstria ; Lasiocampidae ; Geometridae ; Lepidoptera ; niche breadth ; specialization ; plantinsect interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Raupen von Malacosoma americanum (F.), einer oligophagen Art, die sich vor allem auf Prunus und andern baumartigen Rosaceen entwickelt, wurden verglichen mit Raupen der polyphageren Verwandten M. disstria Hb. und zwar im Hinblick auf deren Empfindlichkeit auf Unterschiede im Blatt ihrer gemeinsamen Wirtspflanze, Prunus serotina Ehrh. Das Puppengewicht und die Entwicklungszeit bis zur Verpuppung wurden gemessen bei Raupen, welche auf Blättern von freiwachsenden und von beschatteten Jungpflanzen gezüchtet worden waren. Die Blattunterschiede hatten eine ausgesprochene Wirkung, aber es gab keine Unterschiede in der Reaktion der beiden Arten. Dieser Vergleich lässt vermuten, dass die Empfindlichkeit auf intraspezifische Unterschiede der Wirtspflanzenqualität bei wirtsspezifischen und polyphagen Arten gleich ist. Indessen dürften sich laut anderen Resultaten einige Insektenarten anders verhalten.
    Notes: Abstract Larvae of Malacosoma americanum (F.)(Lepidoptera: Lasiocampidae) an oligophagous species that feeds primarily on Prunus and other rosaceous trees, were compared to larvae of the more highly polyphagous congener M. disstria Hb., with respect to their sensitivity to variation in the foliage of a common host plant, Prunus serotina Ehrh. Pupal weight and time to pupation were measured on larvae reared on foliage from open-grown and from shaded saplings. The difference in foliage had a pronounced effect, but no difference was evident between the species in their response to the variation in foliage. This comparison implies that sensitivity to intraspecific variation in host quality does not differ between host-specific and generalized species. However, results from other species suggest that some species of insects do differ in this respect.
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  • 3
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    Entomologia experimentalis et applicata 30 (1981), S. 106-110 
    ISSN: 1570-7458
    Keywords: assimilation efficiency ; growth efficiency ; niche breadth ; specialization ; hostplant relations ; plant-insect interactions ; Malacosoma americanum ; Malacosoma disstria ; Lasiocampidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Raupen von Malacosoma americanum, einer oligophagen Art, die sich vor allem auf Prunus und andern baumartigen Rosaceen. entwickelt, wurden mit Raupen der polyphageren Verwandten M. disstria in Hinblick auf die Verwertung der Blätter ihres gemeinsames Wirtes Prunus serotina verglichen. Wirerhielten ähnliche Werte wie sie früher für andere Lepidopteren publiziert worden waren und zwar in Bezug auf die üblichen Messwerte, Anteil verwertete Nahrung, Wachstum in Trockengewicht pro Einheit gefressene oder verwertete Nahrung. Zudem unterschieden sich die beiden Arten in keiner Masszahl für Effizienz. Unsere Resultate sind im Einklang mit der Folgerung, das spezialisierte phytophage Insekten ihre Wirtspflanzen nicht besser ausnützen als as polyphage Arten tun.
    Notes: Abstract Larvae of Malacosoma americanum (F.) an oligophagous species that feeds primarily on Prunus and other rosaceous trees, were compared to larvae of the more highly polyphagous congener M. disstria Hb., with respect to the efficiency of utilization of the foliage of a common host plant, Prunus serotina Ehrh. We obtained values similar to those reported for other Lepidoptera for the commonly used measures of the fraction of ingested food that was assimilated, and for the growth in dry weight per unit of food ingested or assimilated. Moreover, the two species did not differ in any measure of efficiency. Our results are compatible with the conclusion that specialized phytophagous insects do not use their host plants with greater physiological efficiency than do generalized insects.
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  • 4
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    Entomologia experimentalis et applicata 34 (1983), S. 174-178 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Maruca testulalis ; Pod borer ; Development ; Nutritional suitability ; Host plant ; Crotalaria ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les possibilités de développement larvaire de Maruca testulalis sur les fleurs de huit espèces végétales ont été examinées en laboratoire. La comparaison a porté sur Crotalaria retusa, C. juncea, C. saltiana, C. misereniensis, C. mucronata, C. amazonas, Cajanus cajan et l'hôte principal de cette chenille, Vigna unguiculata. En tenant compte de la mortalité larvaire et des indices de croissance (G.I.), ces plantes ont été divisées en trois catégories principales: 1 celles provoquant une mortalité larvaire de 0–30% et ayant des G.I. ≥60%, constituent les plantes hôtes convenables (Vigna unguiculata seule); 2 les plantes qui provoquent une mortalité larvaire de 30≤50% et ont des G.I. de 30 à 60% de la plante hôte principale (Cajanus cajan, Crotalaria amazonas, C. saltiana, C. mucronata; 3 les plantes qui causent 50–100% de mortalité larvaire et dont les G.I. sont inférieurs à 30% de la plante hôte principale (Crotalaria retusa, C. juncea, C. misereniensis). Les résultats déjà publiés sur les choix du lieu de ponte des femelles et l'utilisation de C. juncea comme plante piège, sont discutés à la lumière de ces données nouvelles.
    Notes: Abstract Flowers of eight plant species were evaluated under laboratory conditions for their suitability as larval growth media for the cowpea pod borer, Maruca testulalis. The plants tested were Crotalaria retusa, C. juncea, C. saltiana, C. misereniensis, C. amazonas, Cajanus cajan and the principal host of the borer, Vigna unguiculata (cowpea), was included for comparison. Based on the data obtained on larval mortality and growth indices (GI) the plants were divided into 3 categories namely: I: Those causing 0–30% mortality and having GI value ≥60% form suitable host plants. This group only included V. unguiculata. — II: Those plant species causing 30≤50% larval mortality and having GI value 30%≤60% of the principal host plant (Cajanus cajan, Crotalaria amazonas, C. saltiana, C. mucronata). This group of species is marginally suitable as hosts. — III: Plants causing 50–100% larval mortality and having GI value ≤30% of principal host plant (C. retusa, C. juncea and C. misereniensis). Previously published data on the oviposition preference of the adult moth are discussed in the light of the present findings and the use of C. juncea as a possible trap crop.
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  • 5
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    Entomologia experimentalis et applicata 34 (1983), S. 203-205 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Sesiidae ; Synanthedon vespiformis ; Paranthrene tabaniformis ; Chamaesphecia empiformis ; Chamaesphecia tenthrediniformis ; Attractants ; Pheromones ; Clearwing moths ; Nemapogon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 6
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    Entomologia experimentalis et applicata 30 (1981), S. 280-292 
    ISSN: 1570-7458
    Keywords: Allozyme variation ; Lepidoptera ; Yponomeuta padellus ; evolutionary stages ; F-statistics ; panmixis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le degré de différenciation génétique en allozymes à des niveaux divers de divergence évolutive (populations conspécifiques, sibling species et non-sibling species) d'Yponomeuta a été déterminé. Les distances génétiques entre des sibling species ou des non-sibling species sont très larges. Il en est conclu que de telles estimations ne fournissent pas beaucoup d'informations sur le phénomène de spéciation même. Des coéfficients de reproduction consanguine (F ST) ont été calculés pour des populations d'Y. padellus provenant de six plantes-hôtes. La valeur moyenne F STest .030±.012. Les valuers de F ST des populations recueillies sur Crataegus, (plante-hôte habituelle d'Y. padellus), sont inférieures 2–3.5 fois à celles des populations de l'ensemble des autres plantes-hôtes. L'apparition de races en fonction de l'hôte, mesurée par les différences importantes dans de fréquences des allozymes entre populations sympatriques sur plusieurs plantes-hôtes, a été examinée dans quatre régions. Il apparaît ainsi que la formation de races en fonction de l'hôte se produit chez Y. padellus et que la spéciation sympatrique est un évènement très vraisemblable.
    Notes: Abstract The amount of genetic differentiation at various levels of evolutionary divergence (conspecific populations, sibling species and non-sibling species) in Yponomeuta was determined. Genetic distances between siblings or non-siblings were found to cover a wide range. It is concluded that such estimates do not give much information on the speciation process itself. Inbreeding coefficients were calculated for populations of Y. padellus from a total of six host plants. The grand mean F ST value is 0.030±0.012. F ST values for populations sampled from Crataegus, the common food plant of Y. padellus, are 2–3.5 times smaller than those for populations from the other food plants taken together. Host race formation, as measured by significant differences in allozyme frequencies between sympatric populations on two or more food plants, was investigated in four areas. Host race formation seems to occur in Y. padellus and sympatric speciation is a likely event.
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  • 7
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    Entomologia experimentalis et applicata 34 (1983), S. 20-26 
    ISSN: 1570-7458
    Keywords: Dioryctria abietella ; Cone pyralid ; Lepidoptera ; Pyralidae ; Sex pheromone, (Z,E)-9,11-tetradecadienyl acetate ; Single sensillum recordings ; Electroantennography ; Gas chromatography ; Mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'analyse en chromatographie gazeuse associée à une détection électroantennographique a montré que l'acétate (Z,E)-9,11-tétradécadiényle (Z,E)-9,11–14:Ac est l'un des composants de la phéromone de Dioryctria abietella Schiff (Lepid.: Pyralidae). Couplage chromatographie en phase gazeuse spectrometrie de masse a montré la présence d'acétate tétradécadiényle avec un spectre de masse et un indice de rétention identiques au Z,E-9,11–14:Ac Un récepteur cellulaire sensible à la fois au Z,E-9,11–14:Ac et à un extrait de la femelle a été identifié sous l'antenne du mâle. Les analyses des antennogrammes et de la cellule isolée ont étayé la caractérisation du composant de la phéromone comme étant Z,E-9,11–14:Ac. Un récepteur cellulaire additionnel sensible à l'acétate (Z.)-9-tétradécadiényle et à l'acétate (Z.E.)-9,12-tétradécadiényle a été trouvé sur l'antenne du mâle, mais il n'était pas activé par l'extrait de la femelle. Sur le terrain Z,E-9,11–14:Ac, présenté seul, attirait des nombres importants de mâles de D. abietella. L'addition de l'acétate (Z)-9-tétradécényle a inhibé l'attraction des mâles par les pièges.
    Notes: Summary Gas chromatographic analyses coupled with electro-antennographic detection indicated that (Z,E)-9,11-tetradecadienyl acetate (Z,E-9, 11–14:Ac) is a pheromone component of the cone pyralid Dioryctria abietella. Gas chromatographic-mass spectrometric analyses confirmed the presence of a tetradecadienyl acetate with mass spectrum and retention index identical to Z,E-9,11–14:Ac. A receptor cell sensitive to both Z,E-9,11–14:Ac and the female extract was identified on the male antenna. An additional receptor cell sensitive to (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate was found on the male antenna but was not activated by the female extract. In the field Z,E-9,11–14:Ac presented alone attracted significant numbers of male D. abietella. Addition of (Z)-9-tetradecenyl acetate inhibited the attraction of males to traps.
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  • 8
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    Entomologia experimentalis et applicata 36 (1984), S. 15-16 
    ISSN: 1570-7458
    Keywords: sex attractants ; Lepidoptera ; Noctuidae ; Orthosia incerta ; Orthosia cruda ; fruit pest ; Z9-14:Ac ; Z9-14:Ald ; Z11-16:Ac ; Z11-16:Ald
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 9
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    Entomologia experimentalis et applicata 34 (1983), S. 65-70 
    ISSN: 1570-7458
    Keywords: Insect growth regulators ; Anti-juvenile hormone ; Fluoromevalonate ; Precocious metamorphosis ; Premature pupation ; Ecdysis ; Fall webworm ; Hyphantria cunea ; Lepidoptera ; Arctiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Fluormevalosäure (FMev), bekannt als ein spezifischer Inhibitor der Biosynthese des Juvenilhormons (JH) in Insekten, wurde in 0,1–50 μg/Tier Dosis topikal an 3., 4. und 5. Larvenstadien von Hyphantria cunea getestet. Die Raupen wurden auf einem semi-synthetischen, künstlichen Nährboden bei 25° und unter Langtagsbedingungen (18 : 6 St., Licht/Dunkel) gezüchtet. Diese Verbindung rief drei verschiedene Typen spezifischer Reaktionen hervor: 1) verfrühte Metamorphose, 2) gehemmte Häutung und 3) verlängerte Larvenentwicklung. Vor der verfrühten Verpuppung wurde normales Verhalten beobachtet. Die Larven des 3. oder 4. Stadiums häuteten sich meist erst nach einem interkalaren Larvenstadium in verfrühte Puppen. Unter den drei Larvenstadien erwies sich das 5. Stadium gegen die Anti-JH-Verbindung am empfindlichsten. In allen getesteten Entwicklungsphasen wiesen die frisch gehäuteten Larven die höchste Empfindlichkeit gegen FMev auf. Nach der Häutung wurde stufenweises Absinken der FMev-Empfindlichkeit beobachtet, im 5. Larvenstadium verursachte die Verbindung jedoch selbst am letzten Tag des Wachstums zu einen relativ hohen Prozentzahl verfrühte Verpuppung. Eine zweite typische Wirkung von FMev war die Hemmung der Häutungsprozesse. Zwei grundlegende Stufen der Häutungsstörungen unterschieden sich voneinander: 1) Als Folge der Anwendung hoher Dosen von FMev konnte die Mehrzahl der Raupen die alte Larvenkutikula nicht öffnen und ging deswegen in kurzer Zeit zugrunde. 2) Bei Behandlung mit niedrigen Dosen der Anti-JH-Verbindung häuteten sich einige Hyphantria-Larven scheinbar normal; nach der Häutung waren aber alle unfähig, die normalen Bewegungen und die Nahrungsaufnahme fortzusetzen. Auch die vorzeitigen Puppenhäutungen wurden in meisten Fällen durch die Anti-JH-Behandlung gehemmt. Die morphogenetischen Wirkungen von FMev konnten durch eine topikale Behandlung mit Hydroprene, einem hochaktiven JH-Analogen, vollständig oder teilweise verhindert werden.
    Notes: Summary Fluoromevalonate (FMev, ZR-3516) known as an inhibitor of JH biosynthesis was topically applied in 0.1 to 50 μg/specimen doses to the 3rd, 4th, and 5th instar caterpillars of Hyphantria cunea Drury. The anti-JH compound induced 3 main types of specific responses: 1) precocious metamorphosis, 2) inhibition of ecdysis, and 3) prolongation of larval development. Precocious pupation was accompanied by behavioural events typical of normal pupation. Third and 4th instar larvae metamorphosed prematurely mostly with the intervention of an intercalary larval instar. The 5th instar exhibited the highest sensitivity to the anti-JH agent. Within each larval stage the freshly moulted insects proved to be the most susceptible to FMev. Afterwards, the incidence of morphogenetic reaction gradually decreased with age. In another fraction of Hyphantria larvae not responding with precocious pupation, FMev evoked varying degrees of ecdysial disturbance which always resulted in the death of caterpillars. In most cases the anti-JH compound inhibited the premature pupal moult, too, and these affected insects died as tanned pharate pupae. A complete or partial “rescue” from the effects of FMev was elicited, if simultaneously or subsequently, a single topical dose of a JH analogue, hydroprene was also administered.
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  • 10
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    Entomologia experimentalis et applicata 30 (1981), S. 123-127 
    ISSN: 1570-7458
    Keywords: Sex Pheromones ; Repellent ; Heliothis armigera ; Heliothis zea ; Lepidoptera ; Noctuidae ; cotton bollworm ; corn earworm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'examen en olfactomètre a porté sur les réactions face à d'autres femelles de la même espèce, de femelles vierges ou ayant copulé d'Heliothis armigera Hübner et H. zea Boddie. Le lot comprenait 8 femelles, vierges ou ayant copulé en présence d'une femelle vierge ou ayant copulé. Les 4 combinaisons possibles de femelles vierges et de femelles ayant copulé ont été examinées avec 12 répétitions pour chaque espèce. Un extrait de l'extrémité de l'abdomen de femelles vierges d'une espèce a été présenté aux femelles de l'autre espèce pour examiner les possibilités de réactions interspécifiques aux phéromones. Pour chaque espèce, les réactions interspécifiques de répulsion entre femelles ont été hautement significatives par rapport aux témoins, à l'exception toutefois des réactions de femelle ayant copulé face à des femelles ayant elles aussi copulé. Les répulsions moyennes chez H. armigera et H. zea pour les 8 femelles de chaque expérience ont été: a) vierges en présence d'une vierge: 7,33 et 7,66; b) vierges en présence d'une femelles ayant copulé: 5,76 et 5,58; c) femelles ayant copulé en présence d'une vierge: 4,67 et 4,83. Les différences sont hautement significatives entre chaque paire de moyennes et entre chaque paire et le lot témoin; 3,17; 3,17; 3,42; 4,00 pour H. armigera; 3,17; 3,50; 2,83 et 3,75 pour H. zea. Les femelles vierges des deux espèces, H. armigera et H. zea ont présenté une réaction de répulsion en présence d'un extrait de l'abdomen de l'autre espèce; les répulsions moyennes étant respectivement 5,53 et 5,33 contre 3,83 et 3,58 pour le lot trémoin. On peut en conclure que ces répulsions doivent entraîner une tendance à la répartition uniforme.
    Notes: Abstract An olfactometer was used to determine the effect of pheromones released by females of the bollworms Heliothis armigera (Hübner) and H. zea (Boddie) on females of the same species. Four combinations of virgin and mated females were tested for repellency of one to the other. Evidence is presented that females of the two bollworms were repelled by females of the same species. In addition, extracts of virgin female abdomens of each species repelled virgin females of the other species.
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  • 11
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    Entomologia experimentalis et applicata 34 (1983), S. 155-162 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Braconidae ; Lepidoptera ; Nymphalidae ; Apanteles bignellii ; Euphydryas aurinia ; Multivoltinism ; Synchronisation ; Weather
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung In einer Population von Euphydryas aurinia (Rottemburg) bei Oxford, England treten während einer Generation von E. aurinia drei Normalgenerationen von Apanteles bignellii Marshall auf. Jede Generation des Parasitoids kann charakterisiert werden durch das befallende Wirtsstadium und durch die aus einem Wirt schlüpfende Zahl Parasitoide. Parasitoide schlüpfen in Normalgenerationen aus dem 3., dem 4. und dem 6. Stadium des Wirts; in Ausnahmegenerationen schlüpfen sie aus dem 2. und 5. Stadium. Bis zu 70 Parasitoide können aus einer Altraupe (6. Stadium) schlüpfen und die Dauer dieses Stadiums kann bis auf 2 Wochen verlängert werden. Die Ausnahmegenerationen von A. bignellii aus Zweitlarven dürften aus Eiablagen in frühe Erstlarven stammen. Fünftlarven des Wirts, aus denen Parasitoide schlüpfen, sind ungewöhnlich klein und fressen nicht; sie dürften das Resultat sein eines Uebermasses von Apenteles-Eiern, die in frühe Viertlarven gelegt wurden. Die Synchronisation zwischen dem Parasitoiden und dem Wirt während der Zeit, da E. aurinia im Puppen-, Adult- oder Eistadium ist, wird aufrechterhalten durch ein verlängertes Coconstadium von Apanteles. Die Puppen des Parasitoiden entwickeln sich normal und die Adulten schlüpfen, bleiben aber bis 4 Wochen lang im Cocon, bevor sie sich eine Ausgangsöffnung machen. Das Wetter kann den Parasitierungsgrad der letzten Wirtsstadien beeinflussen. Wenn der Frühling kalt ist mit klarem Himmel, kann die Synchronisierung zwischen Parasitoiden, die aus Viertlarven des Wirts schlüpfen und potentiellen Fünft- und Sechtstlarven des Wirts schlecht werden. Die Entwicklung von Apanteles-Puppen wird durch die Umgebungstemperatur beeinflusst, während E. aurinia-Larven ihre Temperatur erhöhen, indem sie sich sonnen und deshalb rasch wachsen. Wenn die Parasitoiden unter solchen Bedingungen schlüpfen, sind die meisten potentiellen Wirte schon verpuppt und damit nicht mehr geeignet für die Parasitierung. Die Mechanismen der Synchronisation und der Wettereinfluss auf diese Vorgänge wird diskutiert.
    Notes: Abstract The gregarious endoparasite, Apanteles bignellii Marshall is specific to the nymphalid butterfly, Euphydryas aurinia (Rottemburg) in the British Isles. The synchronisation between host and parasitoid is described at a site near Oxford, England where both occur. Three regular generations of A. bignellii occur in one generation of the host in the studied population. Relevant features of the biology of A. bignellii and E. aurinia are described, including a method of distinguishing the number of Apanteles larval instars based upon shed cuticle remnants. Mechanisms for host-parasitoid synchronisation are outlined, especially a protracted parasitoid cocoon stage when the host is unavailable for attack during the chrysalis, adult and egg stages. Cool, but sunny weather conditions in spring can influence the degree of parasitisation experienced by final instar host caterpillars. The timing of adult A. bignellii emergence and subsequent attack on early instar hosts can lead to additional, partial, generations of parasitoids from second and fifth instar hosts.
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  • 12
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    Entomologia experimentalis et applicata 35 (1984), S. 159-167 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Geometridae ; Ectropis excursaria ; larval dispersal ; colour polymorphism ; phototaxis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Acht Experimente wurden durchgeführt, um einige der Faktoren zu studieren, die das Wanderverhalten der Larven (Raupen) eines polyphagen Geometriden (Ectropis excursaria (Guenée)) beein-flussen. 1. Larven sind positiv phototaktisch. Die positive Phototaxis ist negativ mit Fasten, Alter und Populationsdichte korreliert. Bei hohen Temperaturen ist sie nicht mehr nachweisbar. 2. Das Wanderverhalten der Larven wird durch die Populationsdichte beeinflußt, wodurch annähernd eine konstante Dichte erhalten bleibt. Das Verhalten der individuellen Larven is dabei nicht statistisch homogen. Es gibt ‘Wanderer’ und ‘Nicht-Wanderer’. 3. Diese Verhaltensunderschiede stehen möglicherweise im Zusammenhang mit physiologischen und morphologischen Faktoren, die den individuellen Fortpflanzungserfolg und das überleben beeinflussen können; ‘Wanderer’ sind dunkler, entwickeln sich schneller und das Gewicht ihrer Puppen ist niedriger als das der ‘Nicht-Wanderer’. 4. Eine der larvalen Farbvarianten zeigte eine Präferenz für einen von zwei angebotenen Hintergründen.
    Notes: Abstract The dispersive behaviour of larvae of a polyphagous, wide-spread geometrid (Ectropis excursaria (Guenée)) was studied by examining responses to environmental and endogenous variables. It was found that differences in behaviour can be affected by environmental factors such as light, temperature, density, and plant background as well as some physiological and morphological features. The implications of these relationships are discussed as adaptative strategies to a varying environment.
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    Entomologia experimentalis et applicata 35 (1984), S. 177-193 
    ISSN: 1570-7458
    Keywords: induction of feeding preference ; host plants ; non-host plants ; Manduca sexta ; Sphingidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Vingt-deux espèces de plantes, dont 10 planteshôtes (Solanées), ont été testés comme plantes alimentaires pour des chenilles de ler stade de Manduca sexta. Sur cet ensemble, seulement 12 plantes (dont 9 plantes hôtes) induisaient la prise de nourriture et permettaient la croissance jusqu'au 5ème stade. La diversité des résultats suggère que les plantes pouvaient être classées en hôtes, non-hôtes acceptables et non-hôtes refusés. En utilisant le test du choix alimentaire préférentiel entre deux rondelles de feuilles, les chenilles néonates de ler stade ont préféré nettement les plantes-hôtes aux autres. Cette préférence initiale pour les plantes-hôtes était préservée quand les cheniles étaient élevées sur plantes-hôtes, mais devenait moins nette ou disparaissait pour des chenilles élevées sur d'autres plantes acceptées. Ainsi l'oligophagie ches M. sexta n'est pas induite, mais doit être héritée. Les chenilles néonates, aussi bien que celles de 5ème stade, présentent des préférences hiérarchisées parmi les plantes hôtes ou non. La seule frontiere nette observée était entre espèces de plantes acceptables ou non. Les hiérarchies préférentielles des chenilles du 5ème stade différaient légèrement lors-qu'elles avaient été élevées sur deux plantes-hôtes différentes. La différence essentielle était l'observation d'une préférence accrue pour l'espèce ayant servi à l'élevage, mais deux autres plantes-hôtes changaient aussi de position hiérarchique. La cause de ces changements de préférence a été approfondie, les chenilles étant élevées sur des feuilles de chaque espèce acceptable (hôte ou non). Leurs préférences alimentaires ont été définies en utilisant des combinaisons diverses (hôte x hôte, hôte x non-hôte acceptable, non-hôte acceptable x non-hôte acceptable). L'induction de la préférence alimentaires a été obtenue dans ces trois associations. Ceci montre que l'induction des choix alimentaires chez M. sexta n'est pas limitée aux plantes-hôtes. Le degré d'induction de la préférence alimentaire variait de très fort à indécelable; il dépendait de l'association examinée. La source de la variabilité de cette induction a été examinée en fonction de la relation entre la force de l'induction et les rapports taxonomiques des plantes associées. La relation obervée était inversée pour M. sexta. L'examen des données de la littérature ont révélé une relation du même type pour les autres espèces de Lépidoptères.
    Notes: Abstract Ten host plant (Solanaceae) and twelve non-host plant species were tested as foodplants for first instar larvae of the tobacco hornworm, Manduca sexta. Only nine host and three non-host plant species elicited feeding and supported growth up to fifth instar. The range of acceptability suggested that plants be divided into hosts, acceptable non-hosts, and unacceptable non-hosts. Using the two-choice feeding preference test we found that the initial preference for hosts was preserved when larvae were reared on hosts, but was less strong or absent for larvae reared on acceptable non-hosts. Thus oligophagy in the tobacco hornworm is not induced, but must be inherited. Newly-hatched first instar larvae and fifth instar larvae showed a preference hierarchy among both hosts and non-hosts. Fifth instar larvae reared separately on two different host species showed slightly different preference hierarchies among hosts. The preference for the rearing plant was increased and also two other host species changed positions in hierarchies. Feeding preferences of larvae reared on hosts or acceptable non-hosts were determined using plant combinations of host vs. host, host vs. acceptable non-host, and acceptable non-host vs. acceptable non-host. Induction of feeding preference was found in all three of these categories. This shows that induction of feeding preference in the tobacco hornworm is not restricted to host plant species. The degree to which feeding preferences were induced ranged from very strong to undetectable and dependend on the plant species paired. The strength of induction in the tobacco hornworm was found to correlate inversely with taxonomic relatedness of the plant species paired. Analysis of induction data from the literature revealed a similar correlation for other lepidopteran species.
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  • 14
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    Entomologia experimentalis et applicata 35 (1984), S. 255-261 
    ISSN: 1570-7458
    Keywords: method ; dry matter ; budget ; Lepidoptera ; phytophagous ; gravimetry ; area ; accuracy ; precision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les budgets en matière sèche consommée par des lépidoptères ont été comparés par les méthodes gravimétrique et planimétrique. La méthode gravimétrique est basée sur le rapport poids sec/poids frais de feuilles consommées par les chenilles. Avec la méthode planimétrique, la quantité d'aliment proposée aux chenilles est déterminée par les tracés de la surface des feuilles et le contenu de matière sèche par unité de surface des feuilles. La méthode de planimétrie permet l'utilisation de plus grands rameaux de feuilles et de cages d'élevage extérieures en gaze. Il n'y avait pas de différence appréciable dans les éléments du budget (croissance, ingestion et déjection), ni aucune différence dans la variabilité observée des données attribuable à la méthode utilisée. Cependant, la variabilité attendue d'après la précision des mesures avec la méthode gravimétrique est inférieure à celle de la méthode planimétrique. est inférieure à celle de la méthode planimétrique. Des éléments expérimentaux, inhérents à la méthode gravimétrique, introduisent une variabilité dans les mesures que l'on n'a pas avec la méthode planimétrique. 30–60% de la variabilité dans la consommation ont été attribués à des paramètres internes à la chenille, même quand elles provenaient toutes de la même ooplaque.
    Notes: Abstract Gravimetric and a combination areal-gravimetric methods for determining dry matter budgets for leaf eating Lepidoptera were compared. The gravimetric method is based on dry weight/live weight ratios of the leaves fed to the larvae. In the areal-gravimetric method, the quantity of food offered to the larvae is determined from the area of leaf tracings and the dry matter content per unit area of the leaves. The areal-gravimetric method permits the use of larger leaf sprays and an open, gauze enclosed rearing chamber. There were no consistent differences in budget factors (growth, ingestion or egestion), nor were there any differences in the observed variability of the data attributable to the method used. However, the expected variability based on instrument precision for the gravimetric method is less than for the areal-gravimetric method. Experimental factors inherent in the gravimetric method introduce variability to the measurements that are not present in the areal method. Thirty to 60% of the variability in budget factors was attributed to intrinsic properties of the larvae, even though the larvae were taken from the same egg masses.
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  • 15
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    Entomologia experimentalis et applicata 34 (1983), S. 121-122 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Earias insulana ; Bollworm ; Artificial diets ; Insect fecundity
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  • 16
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; Intragenic recombination ; Mutant polypeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Recombinational analysis of oxil mutants was performed using a and a mutant strains with the same mitochondrial and nuclear backgrounds, derived from strain 777-3A. In spite of minor inconsistencies the overall map of oxi1 mutations can be constructed on the basis of wild-type recombinant frequencies in the two-point oxi1 − − x oxi1 − crosses. The frequencies of wild-type recombinants varied in a wide range from 0.003% to 16%, reaching the maximal values expected for unlinked mitochondria) markers. No distinct clusters of mutants were observed. The analysis of translation products of oxil mutants showed that all but one of the oxil mutants studied are connected with the conspicuous changes of the polypeptide band corresponding to subunit 11 of cytochrome c oxidase in electrophoresis on polyacrylamide gels. The exceptional G565 mutant showed no conspicuous change in subunit II, but lacked subunit I of cytochrome c oxidase. Various oxi1 mutants seemed to carry premature chain termination mutations. Most of them show a correlation between the length of the putative fragment of subunit II synthesized and the position on the genetic map. The direction of translation is from the V2 to the V60 mutation. The V2 mutation is proximal to cap and V60 proximal to the par locus.
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  • 17
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    Current genetics 2 (1980), S. 61-67 
    ISSN: 1432-0983
    Keywords: Axenomycin ; Ribosome genetics ; Yeast ; Protein synthesis
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    Topics: Biology
    Notes: Summary Axenomycin inhibits protein synthesis in vivo and in vitro in Saccharomyces cerevisiae. The antibiotic acts by binding to ribosomes, most probably to the large ribosomal subunit. Mutant strains resistant to axenomycin appear to contain ribosomes that are not inhibited by the antibiotic. The responsible gene has been mapped on the VII chromosome between the centromere and the leu1 gene.
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    Current genetics 2 (1980), S. 207-210 
    ISSN: 1432-0983
    Keywords: Yeast ; Plasmid ; Repair
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    Notes: Summary We have developed a system for assaying pyrimidine dimers in the 2 ⇐m DNA plasmid of Saccharomyces cerevisiae, using Micrococcus luteus UV endonuclease to nick dimer-containing plasmid molecules and measuring percentages of nicked and covalently closed circles on agarose gels. UV-irradiation induced dimers in plasmid DNA, in vivo, at the same rate as in chromosomal DNA. After a dose of 20 Joules·m−2, approximately 86% of plasmid molecules had. at least one dimer. After 3 h incubation under normal growth conditions only 4% still retained dimers in a wild-type strain. In a rad1 (excision-defective) mutant 81% of plasmid molecules still had dimers after 3 h, suggesting that excision repair operates to remove dimers from plasmid DNA in wild-type yeast. Dimers can be removed from 2 ,um DNA in a rad1 mutant by photoreactivation.
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    Current genetics 2 (1980), S. 211-214 
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein dimorphism
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    Topics: Biology
    Notes: Summary Two-dimensional gel electrophoresis was used in a comparative study of ribosomal proteins from various strains of Saccharomyces cerevisiae. The results demonstrated a case of dimorphism of L8 protein of 60S ribosomal subunit. Of eight strains examined, two strains were one type and six were the other type. The former, which was tentatively designated as altered (A) type, was more acidic than the latter, common (C) type, as shown by mobility difference in pH gradient gel. Heterozygous (A/C) diploid cells contained both types of L8 protein and gave rise to tetrads of 2:2 segregation for A and C types, indicating that the difference of mobility was reflection of the allelic difference of the gene coding for L8 protein.
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  • 20
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    Current genetics 1 (1980), S. 177-183 
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein alteration ; Cycloheximide
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    Topics: Biology
    Notes: Summary A spontaneous high-level cycloheximide-resistant mutant of the yeast Saccharomyces cerevisiae (strain cy32) is found to have an altered protein of the large subunit (60S) of cytoplasmic ribosomes, namely protein L29. The resistance character segregates together with this biochemical defect and is semidominant in heterozygous diploids. Judged from in vitro susceptibility to inhibition by cycloheximide there are at least 50% resistant ribosomes present in such diploid strains. From these results it is concluded that cycloheximide resistance of mutant cy32 is caused by mutation of a single gene and that it is the structural gene for L29 which is affected. Preliminary genetic mapping data are also reported. They indicate a location of cyhx-32 marker on chromosome 7 near met13.
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  • 21
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    Current genetics 2 (1980), S. 175-180 
    ISSN: 1432-0983
    Keywords: Yeast ; Hydroxyurea ; DNA synthesis
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    Topics: Biology
    Notes: Summary Newly synthesised DNA molecules the same size as replicons (7 million-60 million daltons) accumulate in yeast cells treated with hydroxyurea. During prolonged incubation in low concentrations of the drug, there is a large accumulation of these molecules without any corresponding increase in their molecular weight. On release from the inhibtion the molecules are converted to large molecular weight DNA. These observations are consistent with an inhibition by hydroxyurea of the joining of completed replicons. In addition, newly synthesised DNA molecules the size of yeast Okazaki fragments also accumulate in cells treated with hydroxyurea.
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  • 22
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    Current genetics 2 (1980), S. 193-200 
    ISSN: 1432-0983
    Keywords: Recombination ; Plasmids ; Transformation ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary [2 μm+ and [2μm°] yeast were transformed to stable leucine prototrophy with the hybrid yeast — E. coli plasmid, pJDB219. This plasmid contains the entire sequence of the endogenous 2 μm yeast DNA plasmid in addition to the yeast nuclear LEU2 + gene and the Co1E1 derivative, pMB9. In the [2 μm+] transformants, a new wholly yeast LEU2 + plasmid, pYX, was generated, probably by a recombination event between pJDB219 and 2 μm DNA. The plamid, pYX, in the absence of 2 μm DNA, was found to exist in equimolar amounts of two forms, A and B, which probably arise by intramolecular recombination across the inverted repeat sequences of the 2 μm DNA portion of the plasmid. pJDB219 was found to require the presence of 2 μm DNA to undergo this intramolecular recombination. The results suggest that 2, μm DNA and pYX code for a gene product required in this recombination event which pJDB219 cannot produce.
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  • 23
    ISSN: 1432-1432
    Keywords: Yeast ; E. coli ; tRNA ; rRNA ; Sequence homologies ; Evolution ; Origins ; Coding mechanism
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    Notes: Summary Many tRNAs ofE. coli and yeast contain stretches whose base sequences are similar to those found in their respective rRNAs. The matches are too frequent and extensive to be attributed to coincidence. They are distributed without discernible pattern along and among the RNAs and between the two species. They occur in loops as well as in stems, among both conserved and non-conserved regions. Their distributions suggest that they reflect common ancestral origins rather than common functions, and that they represent true homologies.
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  • 24
    ISSN: 1432-041X
    Keywords: Vitellin ; Yolk granule ; Yolk protein ; Silkworm ; Embryogenesis ; Immunocytochemistry
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    Notes: Summary Vitellin was purified from eggs of the silkworm,Bombyx mori, by a new method in which vitellin was extracted from isolated yolk granules. The purified vitellin had a molecular weight of 540,000. An antibody against purified vitellin was prepared in rabbits. It reacted with the hemolymph vitellogenin as well as with purified vitellin, but not with other proteins in the hemolymph or in the extract from yolk granules. The anti-vitellin IgG was used to immunocytochemically locate vitellin in theBombyx non-diapause egg during early developmental stages. In the egg, just after oviposition, vitellin was located in internal yolk granules and in small yolk granules of the periplasm. During the early developmental stages studied, vitellin was not metabolized uniformly throughout the egg. The vitellin of the internal yolk granules located at the posterior-dorsal part and of the small peripheral yolk granules was utilized in 16 h and 2 days, respectively, after oviposition. A thin, very vitellin-poor layer was located between the periplasm and the vitellin-rich interior in the newly laid egg. it was always in close contact with the periphery where blastoderm and germ-band cells developed.
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  • 25
    ISSN: 1432-041X
    Keywords: Major haemolymph proteins ; Development ; Cuticle ; Immunocytochemistry ; Ceratitis capitata
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    Notes: Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.
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  • 26
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; Lectin (localization) ; Phaseolus (lectin) ; Phytohemagglutinin ; Seed (lectin)
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    Notes: Abstract We have examined the properties and subcellular localization of phytohemagglutinin (PHA), the major lectin of the common bean (Phaseolus vulgaris.), in the axis cells of nearly mature and imbibed mature seeds. On a protein basis the axis contained about 15% as much PHA as the cotyledons. Localization of PHA was done with an indirect immunolabeling method (rabbit antibodies against PHA, followed by colloidal gold particles coated with goat antibodies against rabbit immunoglobulins) on ultra-thin cryosections which were embedded in plastic on the grids after the immunolabeling procedure. The embedding greatly improved the visualization of the subcellular structures. The small (4 nm) collodial gold particles, localized with the electron microscope, were found exclusively over small vacuoles or protein bodies in all the cell types examined (cortical parenchyma cells, vascular-bundle cells, epidermal cells). The matrix of these vacuoles-protein bodies appears considerably less dense than that of the protein bodies in the cotyledons, but the results confirm that in all parts of the embryo PHA is localized in similar structures.
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  • 27
    ISSN: 1432-2048
    Keywords: Cotyledons ; Endoplasmic reticulum ; Ferritin labeling ; Immunocytochemistry ; Phaseolus ; Protein (reserve) ; Reserve protein
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    Notes: Abstract The ultrastructure of the storage parenchyma cells of the cotyledons of developing bean (Phaseolus vulgaris L.) seeds was examined in ultrathin frozen sections of specimens fixed in a mixture of glutaraldehyde, formaldehyde and acrolein, infused with 1 M sucrose, and sectioned at-80° C. Ultrastructural preservation was excellent and the various subcellular organelles could readily be identified in sections which had been stained with uranyl acetate and embedded in Carbowax and methylcellulose. The cells contained large protein bodies, numerous long endoplasmic reticulum cisternae, mitochondria, dictyosomes, and electron-dense vesicles ranging in size from 0.2 to 1.0 μm. Indirect immunolabelling using rabbit immunoglobulin G against purified phaseolin (7S reserve protein), and ferritin-conjugated goat immunoglobulin G against rabbit immunoglobulin G was used to localize phaseolin. With a concentration of 0.1 mg/ml of anti-phaseolin immunoglobin G, heavy labeling with ferritin particles was observed ober the protein bodies, the cisternae of the endoplasmic reticulum, and the vesicles. The same structures were lightly labeled when the concentration of the primary antigen was 0.02 mg/ml. Ferritin particles were also found over the Golgi bodies. The absence of ferritin particles from other organelles such as mitochondria and from areas of cytoplasm devoid of organelles indicated the specificity of the staining, especially at the lower concentration of anti-phaseolin immunoglobulin G.
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  • 28
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; (PEP carboxylase) ; PEP carboxylase ; Sorghum
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    Notes: Abstract The localization of phosphoenol pyruvate carboxylase (EC 4.1.1.3.1.) in the leaf cells of Sorghum vulgare was investigated by using three techniques: the conventional aqueous and non aqueous methods gave conflicting results; the immunocytochemical techniques clearly showed that the enzyme is predominantly located in the cytoplasm of mesophyll cells.
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  • 29
    ISSN: 1432-0983
    Keywords: Ribosomes ; Antisuppressor ; Yeast
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    Notes: Summary The yeast antisuppressor mutation, asu9-1 (Liebman and Cavenagh 1980) was found to cause an alteration in the 40S ribosomal subunit. Two-dimensional polyacrylamide gel electrophoresis patterns of the 40S ribosomal proteins from four different strains bearing the asu9-1 mutation all contained the same extra protein spot which was completely absent in five strains which did not carry the asu9 mutation.
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  • 30
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial DNA ; Antibiotic resistance mutations
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    Notes: Summary A large proportion of the spontaneous erythromycin resistant mutants isolated from a strain carrying a previously-induced chloramphenicol resistance mutation at cap3 do not map at ery1, the locus most often associated with mitochondrial erythromycin resistance. Most of the new mutations are also nonallelic at spil, spi2, and other known antibiotic resistance loci within the 21S rRNA gene; they are allelic with each other and define the new locus, ery2. Induced second-site erythromycin resistant mutants from the cap r3 strain, as well as spontaneous or induced mutants from strains carrying a cap r 1 mutation, all tend to map at eryl. The cap r3 mutation is apparently necessary for the expression of erythromycin resistance resulting from a second mutation at ery2.
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  • 31
    ISSN: 1432-0983
    Keywords: Yeast ; Thermoconditional DNA repair ; Mutagenesis ; Allelism test
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    Notes: Summary Of two mutant genes (snm1-2 ts and snm2-1 ts) conferring thermoconditional mutagen sensitivity in Saccharomyces cerevisiae one (snm2-1 ts) is shown to be centromere-linked. At the restrictive temperature this allele reduces UV-induced back mutation frequency of the ochre allele hiss-2 but has no influence on forward mutation at the CAN1 locus. Complementation tests and recombination analysis revealed snm2 ts to be allelic with rad5 (rev2).
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  • 32
    ISSN: 1432-0983
    Keywords: Electro-fusion ; Yeast ; Plasmogamy ; Proliferation
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    Notes: Summary Electric field-induced fusion was induced between Saccharomyces cerevisiae protoplasts from the ρ − heterozygous diploid strain 2114 and the respiratory-competent diploid strain 3441, carrying chromosomal markers. Close membrane contact between the cells of the two different strains (ratio 1:1) was achieved by dielectrophoresis in a weak inhomogeneous alternating field (about 1 kV/cm, 2 MHz). Due to dielectrophoresis pearl chains of two or more cells of the two strains are formed between the electrodes. Cell fusion was induced by application of two single square field pulses sufficiently high to induce reversible electrical breakdown in the membrane contact zone between cells within a pearl chain (about 7 to 8 kV/cm field strength and 40 Ms duration). The two subsequent pulses were applied at an interval of about 10 s. Hybrids could be isolated on selection medium in a high yield (compared with conventional fusion techniques). The hybrids were diploid, respiratory-competent and produced prototrophic spores. Thus, the fused hybrids contained only the chromosomal markers of strain 2114 and the cytoplasmic marker for respiratory competence from strain 3441; electro-fusion thus resulted mainly in plasmogamy.
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    Current genetics 6 (1982), S. 93-98 
    ISSN: 1432-0983
    Keywords: Yeast ; Genetic mapping ; Trisomic analysis ; Arginine
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    Topics: Biology
    Notes: Summary By use of a set of 8 aneuploid strains of the yeast Saccharomyces cerevisiae, carrying from 1 to 5 identified disomic chromosomes, in crosses to a set of haploid strains collectively bearing 11 unmapped genes, the following chromosome assignments were obtained for these unmapped genes: arg80 on XIII;arg3 on X;car2 on XII; cpa1 and tsm8740 on XV; tsm7269 (=rna6) on II; cpa2 on X or XV; arg82 and tsm4572 on III, IV or XVI; car1 and arg81 on II, IV, VI, VII or XVI. Linkage tests between the unmapped genes and markers located on the chromosomes that had been designated as possible carriers by the previous analysis allowed 8 genes to be localized. The remaining three genes, cpa2, car1 and arg81 (located on fragment F8), could not be positioned on any of the chromosomes indicated by the trisomic analysis, in spite of testing for linkage to markers covering most of the known regions of these chromosomes.
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  • 34
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    Current genetics 8 (1984), S. 49-55 
    ISSN: 1432-0983
    Keywords: Protoplast fusion ; Yeast ; Yarrowia lipolytica ; Kluyveromyces lactis
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    Topics: Biology
    Notes: Summary Prototrophic hybrids have been obtained by the fusion of auxotrophic haploid strains of the two yeasts Yarrowia (Saccharomycopsis) lipolytica and Kluyveromyces lactis. The hybrid fusants had a colonial morphology intermediate between that of the two parent strains, were uninucleate, and contained an approximately diploid amount of DNA per cell. The growth rates of all the fusants on a minimal glucose medium were slower than those of the two parents. Two of the fusants studied could utilise a novel range of carbon sources. All of these data suggested that the hybrids contained a diploid nucleus formed by the fusion of the two haploid parental nuclei. However, analytical CsCl density gradient centrifugation demonstrated that the nuclear DNA of the fusants was derived almost entirely from the Y. lipolytica parent. Moreover, an examination of the protein constitution of the fusants by two-dimensional gel electrophoresis showed that their protein patterns were indistinguishable from that of Y. lipolytica. Two possible mechanisms for the formation of a diploid nucleus containing DNA derived almost entirely from one of the haploid parents are discussed.
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    Current genetics 7 (1983), S. 473-480 
    ISSN: 1432-0983
    Keywords: ars sequences ; Yeast ; Chlamydomonas
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    Notes: Summary A hybrid plasmid (pLG4) containing pBR325 and the yeast arg4 gene was constructed then used to isolate DNA fragments of Chlamydomonas able to promote high frequency transformation of yeast. Three plasmids containing EcoRI restriction fragments of chloroplast DNA and two plasmids containing Aval fragments of nuclear DNA were shown to support autonomous replication of plasmids in yeast. The three EcoRI fragments correspond to restriction fragments R4, R5 and R11 of native chloroplast DNA. These fragments are clustered in the physical map of chloroplast DNA constructed by Rochaix (1978). All isolated plasmids were shown to transform yeast at high frequency but the yeast transformants were quite unstable mitotically. Potential cloning sites are still available in the new plasmids which could be used as vectors in yeast and possibly in Chlamydomonas itself.
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  • 36
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial DNA ; Antibiotic resistance mutations ; Suppressor
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    Notes: Summary Strains that are genotypically sensitive to chloramphenicol and also contain one of the nuclear suppressors of mitochondrial chloramphenicol resistance (Waxman et al. 1979) were constructed. A manganese mutagenesis on such a strain produced chloramphenicol resistant mutants, most of which resulted from mutations in nuclear genes. These mutants may be either dominant or recessive, and they probably do not code for membrane proteins. The few mitochondrial mutants fall into several classes, but all result from mutations in the 21S rRNA gene. The suppressor allele effectively prevents the appearance of the most common group of mitochondrial mutants (those that map at cap1), and thereby enhances the selection of novel mutants in the region.
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  • 37
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    Current genetics 3 (1981), S. 213-220 
    ISSN: 1432-0983
    Keywords: Mitochondrial genetics ; Yeast ; Suppressiveness ; Triploid analysis
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    Notes: Summary A genetically defined highly suppressive petite yeast strain (ρ −cob+AsEoCoOoPo) was crossed with a grande strain carrying a multiply marked mitochondrial genome (ρ +ArErCrO rpr). Petite diploid progeny, isolated from individual zygotic clones consisting either of wholly petite or mixtures of grande and petite cells, were characterised genetically by crossing to grande haploids. The diploid petites were found to closely resemble the petite parent and in general not to carry mitochondrial markers from the grande parent. In the petites from the mixed clones recombination was detected, but only within the region of homology between the genomes. These observations are inconsistent with models of suppressiveness based on destructive recombination and suggest that the petite genome eliminates the grande genome from zygotic progeny through being preferentially replicated. The most plausible model to explain the observed pattern of zygotic clones postulates a limited number of mDNA replication sites in zygotes, competition for sites between input mDNA molecules and an advantage in this competition for suppressive ρ − mDNA.
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  • 38
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    Current genetics 3 (1981), S. 229-233 
    ISSN: 1432-0983
    Keywords: Yeast ; Nascent DNA
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    Notes: Summary Two species of newly synthesised DNA larger than average replicons have been found in yeast. Their molecular weights are 60 million and 90 million daltons respectively. The exact nature of these molecules is not certain. They may represent entirely novel species of cellular DNA or they could be concatameric replication intermediates of some particular fraction of DNA, such as mitochondrial DNA or rDNA. Alternatively they could result from the fusion of adjacent completed replicons in a small cluster.
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  • 39
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    Current genetics 5 (1982), S. 153-155 
    ISSN: 1432-0983
    Keywords: Yeast ; Mutant cell-wall ; Permeability exponentialy
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    Notes: Summary When Saccharomyces cerevisiae SY15 rho° mutant cells grown in media stabilized with 10% sorbitol were suspended in 2% sorbitol solutions, 60–70% of the population did not lyse and became permeable to native high molecular weight DNA. Maximal incorporation of DNA to DNase resistant state was measured after 60 min of incubation in presence of 5 μg/ml DNA and 10 mM CaCl2. These results suggest that the fragile mutants might be tested as hosts for transformation of whole yeast cells.
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  • 40
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; Intragenic recombination ; Mutant polypeptides
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    Notes: Summary Genetic and biochemical studies were performed with mutants allocated to the mitochondrial oxi2 gene. Recombinational analysis of 19 oxi2 mutants was performed using α and a mutant strains derived from the same genetic background. The frequencies of wild-type recombinants in oxi2 − × oxi2 − crosses varied from 0.002 to 17%. The map of oxi2 mutations constructed on the basis of these frequencies shows many internal inconsistencies. In the course of rho − deletion mapping five classes of oxi2 mutations were distinguished. The results of deletion analysis are in agreement with those of recombinational mapping. The analysis of mitochondrial translation products by SDS-polyacrylamide electrophoresis of 20 oxi2 mutants shows that 17 of them are connected with conspicuous changes of 22 kd polypeptide band corresponding to subunit III of cytochrome oxidase. At least four of them carried instead of subunit III clearly visible significantly shorter polypeptides (12.8 to 20.1 kd). These were, most likely, shorter fragments of subunit III resulting from chain termination mutations. Colinearity was observed between the lenght of new polypeptides and the positions of the respective mutations on the recombinational map. These data confirm hat oxi2 encodes subunit III of cytochrome oxidase and suggest that translation of the oxi2 gene is in the direction from V303 to V273.
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  • 41
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    Current genetics 7 (1983), S. 285-288 
    ISSN: 1432-0983
    Keywords: Arginyl-tRNA-Protein transferase ; Yeast ; Post-translational modification
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    Notes: Summary A mutant of Saccharomyces cerevisiae deficient in arginyl-tRNA-protein transferase has been isolated. The responsible mutation designated ate1, was localized near the centromere of chromosome VII. It probably involves the structural gene for the transferase since residual enzyme activity in the mutant is temperature-sensitive.
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  • 42
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    Current genetics 7 (1983), S. 489-492 
    ISSN: 1432-0983
    Keywords: Mitochondrial genes ; Yeast ; Vegetative segregation
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    Notes: Abstract Genes in mitochondria and chloroplasts segregate rapidly during vegetative reproduction. Models to explain this vegetative segregation invoke either random segregation of organelle DNA molecules, or nonrandom segregation with random recombination events. All such models are basically stochastic. To look at vegetative segregation we took heteroplasmic (HET) cells containing mitochondrial mutations at the cap1, eryl and olil loci from several crosses. HETs were repeatedly selected and subcloned. Even after three to five successive subclonings (approximately 60–100 generations) some cells remained heteroplasmic. This confirms and extends previous observations of persistent HETs by Rank and Bech-Hansen (1972) and Forster and Kleese (1975), and by Bolen et al. (1980) for chloroplast genes in Chlamydomonas.
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  • 43
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    Current genetics 8 (1984), S. 29-32 
    ISSN: 1432-0983
    Keywords: Antisuppression ; Suppression ; tRNA ; Yeast
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    Notes: Summary The effect of a previously isolated antisuppressor mutation from bakers' yeast, that reduced the efficiency of the tyrosine-inserting ochre suppressor, SUP7-o, on other tyrosine-inserting ochre suppressors has been determined. As expected, the antisuppressor mutation, mod5-1, restricted the capacity of all eight tyrosine-inserting ochre suppressors to suppress nonsense mutations. Based on the suppression of five ochre alleles in the presence of mod5, the eight class I suppressors can be grouped into three subclasses. The most efficient subclass had only one member, SUP4-o. Members of the second group included SUP2-o, SUP3-o, SUP7-o, and SUP8-o. The third and least efficient subclass included SUP5-o, SUP6-o, and SUP1 1-o. These differences in efficiencies are a function of the relative expression of the eight genes encoding tRNATYR.
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  • 44
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    Current genetics 8 (1984), S. 85-92 
    ISSN: 1432-0983
    Keywords: Chromosome map ; Yeast ; Schizosaccharomyces pombe ; Gene conversion
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    Notes: Summary The genetic map of the nuclear genome of the fission yeast Schizosaccharomyces pombe has been extended by mitotic and meiotic mapping data. A total of 158 markers are now assigned to the three linkage groups known in this organism, and 118 of them have been located on the corresponding chromosome map. Chromosome II and III each consist of one linkage group. There is some indication that the two large fragments which define chromosome I are meiotically linked, but the linkage observed is significant at the P = 0.05 level only. The length of the map is at least 1,700 map units, corresponding to an average of about 8 kilobases per map unit. The latter figure is comparable to the one obtained for intragenic recombination in the sup3 gene (Hofer et al. 1979). The basic frequency of gene conversion as measured for 21 genes varies according to a distribution of Poisson (with a modal value of 0.6% conversion per meiosis and per gene), in sharp contrast with Saccharomyces cerevisiae (Fogel et al. 1980) and Ascobolus immersus (Nicolas 1979). This may reflect the rarity of gene or region-specific rec alleles in S. pombe and may be related to the homothallism of this organism.
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  • 45
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    Current genetics 8 (1984), S. 353-358 
    ISSN: 1432-0983
    Keywords: Hygromycin B ; Yeast ; Plasmids
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    Notes: Summary Saccharomyces cerevisiae is normally sensitive to the drug hygromycin B; a hygromycin B concentration of 200 µg/ml in agar plates is sufficient to completely inhibit growth. We constructed yeast-E. coli bifunctional plasmids which confer hygromycin B resistance to Saccharomyces cerevisiae. Promoters and amino terminal coding regions of a heat shock gene, a heat shock cognate gene, and the phosphoglycerate kinase gene from yeast were fused to a bacterial hygromycin B resistance gene. In all three cases, yeast cells containing plasmids with the hybrid hygromycin B resistance gene were resistant to high levels of the drug. Yeast cells containing these plasmids can also be directly selected after transformation by using hygromycin B. The intact bacterial hygromycin B resistance gene and the kanamycin resistance gene from Tn903 were also tested in yeast for their ability to confer resistance to hygromycin B and G418. The intact bacterial genes were not effective in conferring drug resistance to yeast cells.
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  • 46
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    Current genetics 7 (1983), S. 85-92 
    ISSN: 1432-0983
    Keywords: Yeast ; RAD52 ; Cloning ; S1 and BAL31 Deletions
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    Topics: Biology
    Notes: Summary The RAD52 gene of Saccharomyces cerevisiae has previously been shown to be involved in both recombination and DNA repair. Here we report on the cloning of this gene. A plasmid containing a 5.9 kb yeast DNA fragment inserted into the BamH1 site of the YEp13 vector has been isolated and shown to complement the X-ray sensitive phenotype of the rad52-1 mutation. The rad52-1 cells containing the plasmid form larger colonies than similar cells having lost the plasmid. This plasmid has been shown not to complement either the U.V. sensitivity or the recombination defect of the E. coli recA mutation. From the insert various fragments have been subcloned into the YRp7 and YIp5 vectors. Integration events of two of the subclones have been genetically mapped to the chromosomal location of RAD52, indicating that the structural gene has been cloned. A 1.97 kb BamH1 fragment subcloned into YRp7 in one orientation complements the rad52-1 mutation, while the same fragment in the opposite orientation fails to complement. Various other subclones indicate that a BglII site, within the BamH1 fragment, is in the RAD52 gene. This BglII site has been deleted by Sl-nuclease digestion and the resulting deletion inactivates the RAD52 gene. BAL31 deletions from one end of a 1.9 kb Sal1-BamH1 fragment have been isolated; up to 0.9 kb can be deleted without loss of RAD52 activity, indicating that the RAD52 gene is approximately 1 kb or less in length.
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  • 47
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    Current genetics 8 (1984), S. 69-76 
    ISSN: 1432-0983
    Keywords: Yeast ; Ethidium bromide ; Meiosis
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    Notes: Summary Ethidium bromide was found to inhibit nuclear and mitochondrial DNA synthesis during meiosis which resulted in the inhibition of meiotic gene conversion and sporulation and was also lethal. Protection from the effects of ethidium bromide on meiotic gene conversion and survival was found to coincide with DNA synthesis, but it is possible that protection from sporulation inhibition occurs only later in meiosis.
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  • 48
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    Current genetics 8 (1984), S. 333-340 
    ISSN: 1432-0983
    Keywords: polA+ ; DNA polymerase I ; Cloning ; Yeast
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    Notes: Summary The E. coli polA + gene has been subcloned from a specialised λ transducing phage onto a low copy number plasmid. Plasmid-encoded DNA polymerase I was synthesised at 2 to 3 times the wild-type E. coli level, and was biochemically indistinguishable from chromosomally-encoded protein. It was able to counteract the radio sensitivity of polA1, polAex1, polAex2 and polA12 mutants, but no complementation of polA107 mutants occurred, even though the plasmid polA+ gene was expressed. S. cerevisiae ars-1 or 2 μ replicative sequences were introduced into the polA+ plasmid. Transformation of yeast with these constructs increased total DNA polymerase levels 2–20 times, depending upon assay conditions. The additional activity was discriminated from yeast DNA polymerases by its ability to use low concentrations of substrate, by its resistance to chemical inhibition, and by co-electrophoresis with pure DNA polymerase I and its proteolytic fragments. The polA+ gene was expressed in yeast without the aid of yeast promotor sequences. However, deletion of cloned DNA more than 99 base pairs in front of the structural gene prevented expression in yeast but not in E. coli, indicating that the two organisms use different sequences for expression of the plasmid polA+ gene.
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  • 49
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    Current genetics 8 (1984), S. 471-475 
    ISSN: 1432-0983
    Keywords: β-Glucanase ; Expression ; Heterologous DNA ; Yeast
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    Notes: Summary A cloned endo-1,3-1,4-β-glucanase gene from the Gram-positive bacterium B. subtilis has been located by deletion analysis on a 1.4 kb PvuI-ClaI DNA fragment. This gene has been sub-cloned in the yeast LEU2 vector pJDB207 to produce a hybrid plasmid designated pEHB9. pEHB9 has been transformed to S. cerevisiae and shown to direct the synthesis of an endo-1,3-1,4-β-glucanase in yeast. The β-glucanase activity was low and could only be detected in crude cell extracts of yeast harbouring pEHB9.
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  • 50
    ISSN: 1432-0983
    Keywords: Regulation ; Urea ; Catabolism ; Yeast
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    Notes: Summary Urea amidolyase and the high affinity urea uptake system are induced by allophanate. durM − and durL − recessive mutations, which are easily obtained, totally prevent this induction. They are not linked to each other nor to the concerned structural genes. Despite an intensive hunt, no mutation of repressor or classical operator type has been selected. We conclude that urea amidolyase and urea uptake induction involves at least two positive elements coded for by the durM and durL genes.
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  • 51
    ISSN: 1432-0983
    Keywords: Yeast ; Catalase ; Trehalose ; Glycogen
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    Notes: Summary Mutations at the GLC1 locus in Saccharomyces cerevisiae result in a major deficiency in synthesis of catalase T, but do not affect catalase A. Three independent glc1 mutations were shown to have the same pleiotropic phenotype: catalase T deficiency, defective glycogen synthesis and defective trehalose accumulation. These three deficiencies appear to be determined by a single, nuclear gene. The possibility that glc1 mutations alter a protein kinase is considered.
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  • 52
    ISSN: 1432-0983
    Keywords: Arginine catabolism ; Regulation ; Ornithine transaminase ; Double induction ; Yeast
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    Notes: Summary Yeast ornithine transaminase is known to be induced by arginine and ornithine, through the action of regulatory elements common to arginase induction. We show here that it is subject to a second induction circuit, that which is responsible for urea amidolyase and urea permease induction by allophanate and defined by the regulatory mutants durL − and durM −
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  • 53
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    Current genetics 7 (1983), S. 69-72 
    ISSN: 1432-0983
    Keywords: Yeast ; Protoplast ; Cybrid ; Plasmid
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    Notes: Summary Data presented here demonstrate that fusion of protoplasts of two different haploid strains of Saccharomyces cerevisiae having the same mating type leads to the formation of “fusants” and “cytoplasmic hybrids”. The nuclear and cytoplasmic genome of a “fusant” combine those of the parent haploid strains. The “cytoplasmic hybrid” possesses the haploid genome of one parent and the combined cytoplasmic genomes of both. In mouse cells lines such products have been termed “cybrids” and this term has therefore been adopted here (Bunn and Wallace 1974).
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  • 54
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    Current genetics 7 (1983), S. 93-100 
    ISSN: 1432-0983
    Keywords: Yeast ; RAD genes ; Cloning
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    Notes: Summary Plasmids that complement the yeast mutations rad50-1, rad51-1, rad54-3 and rad55-3 were obtained by transforming strains that carried a leu2 marker and the particular rad mutation, with YEp13 plasmids containing near random yeast DNA inserts. Integration of these plasmids or of fragments of these plasmids was accomplished. Genetic studies using the integrants established the presence of the genes RAD51, RAD54 and RAD55 in the respective plasmids. However, a BamHI subclone of the rad50-1 complementing plasmid failed to integrate at the RAD50 locus, indicating that no homology exists between this fragment and the RAD50 gene. A BamHI fragment from the RAD54 plasmid was shown to be internal to the RAD54 gene: its integration within a wild type copy of RAD54 causes the cell to become Rad−; its excision is X-ray inducible and restores the Rad+ phenotype. Since cells bearing a disrupted copy of RAD54 are able to survive, we conclude that this gene is not essential.
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  • 55
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    Current genetics 6 (1982), S. 99-103 
    ISSN: 1432-0983
    Keywords: Ultraviolet light mutagenesis ; Mitochondrial genome ; Meiosis ; Yeast
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    Notes: Summary Clones derived from ascospores from ultraviolet irradiated diploid cells were examined for the genetic determinants or respiratory properties. Approximately 10% of the cells produced petites of mitochondrial origin at the dose applied. Among 13 asci which produced mitochondrial petites with high frequencies, 6 asci of uniparental type, 0 grandes : 4 petites, were observed. Furthermore, most of the petite spore clones from each individual uniparental ascus showed similar levels of suppressiveness and of mitochondrial gene retention. From these results it is suggested that a single mitochondrial genome participates meiosis in yeast.
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  • 56
    ISSN: 1432-0983
    Keywords: Yeast ; Mutant ; Uncoupler ; Resistance ; Permeability
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    Notes: Summary One mutant resistant to carbonylcyanide m-chlorophenylhydrazone (CCCP), an uncoupler of oxidative phosphorylation, was isolated in Saccharomyces cerevisiae. Genetic analysis showed that a single nuclear gene is responsible for increased resistance; this gene was dominant. The mutant showed cross-resistance or collateral sensitivity to several chemically-unrelated inhibitors (cycloheximide, dinitrophenol, tributhyltin chloride, chloramphenicol). The resistance of the mutant is related to a decreased uptake of CCCP which is not expressed in glucose-starved cells. It was shown that glucose induced a CCCP efflux which was more efficient in the mutant than in the wild-type cells. This effect was correlated to a greater acidification of the internal pH by glucose addition in the mutant cells. It was proposed that resistance was not due to a change of permeability of the plasmic membrane itself but to the change of internal pH which determines the extent of accumulation of weak acids or bases.
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  • 57
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    Current genetics 8 (1984), S. 567-573 
    ISSN: 1432-0983
    Keywords: Non-Mendelian ; Yeast ; Suppressor
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    Notes: Summary Omnipotent suppressors cause translational ambiguity and have been associated with poor growth and inviability. We now report that a non-Mendelian element, [eta+], causes this inviability. In [eta−] strains the suppressors are not inviable. The [eta+] genetic element segregates to about 70% of the meiotic progeny, although almost all of the spores probably have the [eta+] phenotype for the first few divisions. Growth on 5 mM guanidine hydrochloride efficiently causes [eta+] strains to become [eta−]. The [eta+] factor has many similarities with the previously described [psi+] factor (Cox 1965, 1971). However, [eta+] and [psi+] differ in their patterns of inheritance, and by the fact that [psi+] affects ochre specific and not omnipotent suppressors, while the converse is true of [eta+].
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    Current genetics 6 (1982), S. 179-188 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondria ; var1 gene
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    Notes: Summary Several mit mutants mapping within or near the var1 determinant region have been characterized genetically and biochemically. These mutants were isolated using a new enrichment protocol which simplifies the isolation and identification of rare respiration-deficient mutants of yeast. Two of the mutants, PZ200L and PZ206, map in genome segments which flank the known varl gene reading frame; nevertheless, both belong to the same complementation group, apparently that of the varl gene. A third mutant, PZ200R is closely linked to one of the varl allelic determinants now known to be a short insertion within the gene. All three var1 mutants exhibit decreased levels of mitochondrial protein synthesis and negligible activity of the respiratory enzyme complexes. Another cluster of mutants belonging to a separate complementation group from that defined by PZ200L and PZ206 was also mapped and it contains mutants in the nearby serine tRNA gene. The isolation of these mutants in the varl region shows that the varl locus contains information essential for the maintenance of respiration-competent mitochondria. Because these mutants affect mitochondrial protein synthesis, their existence supports the previous hypothesis that the varl protein is an integral component of mitochondrial ribosomes. Furthermore, the mutant sites are present in a DNA sequence that is highly, rich in A+T residues that also contains a gene. Since approximately 50% of the yeast mitochondrial genome is similarly rich in A+T and since most of those regions have not yet been sequenced it is quite possible that other A+T-rich genes may exist.
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  • 59
    ISSN: 1432-0983
    Keywords: Nitrosoguanidine ; Comutation ; Yeast ; Chromosome replication pattern
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    Notes: Summary Contrary to what happens in bacteria, mutations induced by nitrosoguanidine in yeast are not accompanied by an excess of mutations in nearby genes. We have investigated nitrosoguanidine mutagenesis in three regions of the yeast genome: the contiguous DNA segments HIS4A, HIS4B and HIS4C, located on chromosome III; ADE1 and CDC15 separated by about 3 map units on chromosome I; and CAN1, some 50 map units away from the centromere on chromosome V. Revertants at HIS4C never suffered mutations at HIS4A or HIS4B. Reversion at CDC15 did not affect the frequency of mutation at ADE1. No tsm mutations, leading to thermonsensitivity, were found in the immediate vicinity of the locus CAN1 after selecting for canavanine resistant mutants. However, as expected from nitrosoguanidine mutagenesis of replication points and the fixed pattern of chromosome replication, the induced tsm mutations seem not to map randomly over the yeast genome; in fact, two out of the three groups of such tsm mutations studied are located in the same chromosome arm as CAN1, indicating that these two regions are replicated at the same time as CAN1. Replication synchrony is less than perfect, since the tsm mutations of each group affect many different genes.
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  • 60
    ISSN: 1432-0983
    Keywords: Canavanine ; Yeast ; Plasmids
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    Notes: Summary We have found that the application of the amino acid analog canavanine to a culture of yeast cells transformed with chimeric plasmids based on the yeast 2-µm DNA plasmid increases the percentage of cells which have lost the transforming plasmid. This effect is found whether the plasmid carries the CAN1 sensitive allele and the yeast strain carries a can1 mutation confering resistance, or the plasmid contains no CAN1 allele and the yeast strain carries the wild-type CAN1 sensitive allele. Canavanine exerts this effect on yeast strains transformed with chimeric plasmids containing either a portion or the entire 2-µm DNA plasmid, yet canavanine does not appear to effect the maintenance of the native 2-µm DNA plasmid complement within the cell. The effect of canavanine on strains transformed with chimeric plasmids is the same whether or not the yeast strain also contains native 2-µm plasmid DNA. Neither the amino acid analog ethionine, the protein synthesis inhibitor cycloheximide, nor the DNA replication inhibitor hydroxyurea exhibit this effect. Some of the experimental results suggest that canavanine may be a curing agent rather than an agent which selects for spontaneous plasmid loss.
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  • 61
    ISSN: 1432-0983
    Keywords: Yeast ; Polyamines ; Termination ; In vitro Translation
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    Notes: Summary The effects of polyamines (spermidine and putrescine) on yeast suppressor tRNA-mediated readthrough of amber and UGA termination codons, in a homologous cell-free system, was examined. The efficiency of readthrough in a [psi+] lysate, mediated by exogenous suppressor tRNA, was significantly increased by polyamines as was the efficiency of endogenous UGA readthrough. The addition of polyamines, in the absence of exogenous suppressor tRNA, did not induce amber or ochre readthrough, nor could polyamines restore efficient termination readthrough in [psi−] lysates. It is concluded that polyamines interact with tRNA to increase the strength and specificity of the codon: anticodon interaction.
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  • 62
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    Current genetics 8 (1984), S. 265-270 
    ISSN: 1432-0983
    Keywords: DHF Reductase ; Cloning ; Trimethoprim ; Yeast
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    Topics: Biology
    Notes: Summary The dihydrofolate reductase gene of Saccharomyces cerevisiae has been isolated by selection of trimethoprim resistant Escherichia coli transformed with a gene bank of yeast DNA in plasmid pBR322. From 9.2 kilobase pair BamHI DNA fragment this gene has been localized to a 1.76 kb fragment, the restriction map of which appears different from those reported for the E. coli and the mouse dihydrofolate reductase genes. The enzyme encoded by the chimeric plasmid was established as yeast dihydrofolate reductase by its sensitivity to antifolates in vivo through growth studies and in vitro by enzyme assay. Since, the expression of this gene occurs independent of its orientation within the chimeric plasmid, the 1.76 kb fragment may contain functional regulatory sequences in addition to the structural sequences for yeast dihydrofolate reductase.
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  • 63
    ISSN: 1432-0983
    Keywords: Yeast ; Ribosomal protein gene ; Sequence analysis ; Northern blot
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    Notes: Summary Sequence analysis revealed that a gene coding for yeast ribosomal protein L34 comprises an amino acid coding region of 339 nucleotides which is interrupted by an intron after the 19th codon. Like for other yeast ribosomal protein genes analyzed thus far a strong codon bias was observed. The flanking and intervening sequences of this gene encoding L34 show several elements that are conserved in a number of split ribosomal protein genes in yeast. Northern blot analysis using an intron-specific probe demonstrated that the sequenced gene copy coding for L34 is transcribed in vivo.
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  • 64
    ISSN: 1432-0983
    Keywords: Yeast ; Cycloheximide ; Ribosomal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At least four different mutations at the cyh2 locus (rp1X; gene product: YL24) of Saccharomyces cerevisiae confer cycloheximide resistance. The mutant YL24 proteins are either more basic (high-level resistant phenotype), more acidic (low-level resistant phenotype), or unchanged in their electrophoretic mobility (both low-and high-level resistant phenotypes). None of the mutations at other loci seem to induce high-level resistance to cycloheximide.
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  • 65
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    Current genetics 5 (1982), S. 171-180 
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial genes ; Vegetative segregation
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    Topics: Biology
    Notes: Summary A three-factor cross of Saccharomyces cerevisiae involving the cap1, ery1, and oli1 loci was done, with partial pedigree analyses of 117 zygotes. First, second, and third buds were removed and the genotypes of their diploid progeny determined, along with those of the residual zygote mother cell. Results were analyzed in terms of frequencies of individual alleles and of recombinant genotypes in the dividing cells. There is a gradual increase in the frequency of homoplasmic cells and in gene frequency variance during these three generations, as would result from stochastic partitioning of mtDNA molecules between mother and bud, probably coupled with random drift of gene frequencies in interphase cells. These phenomena are more pronounced for buds than for mothers, suggesting that buds receive a smaller sample of molecules. End buds are more likely to be homoplasmic and have a lower frequency of recombinant genotypes than do central buds; an end bud is particularly enriched in alleles contributed by the parent that formed that end of the zygote. Zygotes with first central buds produce clones with a higher recombination frequency than do those with first end buds. These results confirm previous studies and suggest that mixing of parental genotypes occurs first in the center of the zygote. If segregation were strictly random, the number of segregating units would have to be much smaller than the number of mtDNA molecules in the zygote. On the other hand, there is no evidence for a region of the molecule (“attachment point”) which segregates deterministically.
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  • 66
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    Current genetics 6 (1982), S. 29-30 
    ISSN: 1432-0983
    Keywords: Yeast ; Plasmid ; Repair ; Ligase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We show that the DNA ligase encoded or controlled by the cdc9 gene in Saccharomyces cerevisiae is required for replication of plasmid DNA but that excision repair of pyrimidine dimers in plasmid DNA can be completed in its absence.
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  • 67
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    Current genetics 6 (1982), S. 195-201 
    ISSN: 1432-0983
    Keywords: Benomyl resistance ; Yeast ; Mitosis ; Cell cycle mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have isolated 150 benomyl resistant mutants of the fission yeast Schizosaccharomyces pombe. Seven of these mutants were found to be cold sensitive for mitosis. These mutants were the subject of physiological, cytological and genetical characterisation. Growth and division of the seven mutants were similar to the wild type strain at 35 °C. After shift from the permissive (35 °C) to the restrictive temperature (20 °C) the mutants became blocked in mitosis whilst cellular growth continued. Consequently, elongate cells were formed. Six of the seven benomyl resistant mutants became blocked in mitosis at 20 °C with a single aberrant nucleus. In every case the benomyl resistant and cold sensitive phenotype was due to a mutation in a single nuclear gene. These mutants were found to comprise a single genetic linkage group (ben4) and were unlinked to existing TBZ/MBC resistant mutants of S. pombe. Whilst no cross resistance was found in our mutants to TBZ, six of the seven mutants were super sensitive to the spindle poison CIPC. We believe that the phenotype exhibited by these mutants is consistent with a defective tubulin subunit.
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  • 68
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    Current genetics 7 (1983), S. 79-84 
    ISSN: 1432-0983
    Keywords: ars sequences ; Ustilago ; Yeast
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    Topics: Biology
    Notes: Summary U. maydis chromosomal DNA sequences which promote the autonomous replication of plasmid YIp5 in S. cerevisiae YNN27 have been isolated and three of them characterised in some detail. Their properties are idential to yeast ars sequences in that plasmids containing them are maintained extrachromosomally as circular double-stranded DNA molecules, are mitotically unstable in yeast transformants and transform yeast at high frequencies. There is no sequence homology between the three U. maydis sequences and they are not reiterated in the U. maydis genome.
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  • 69
    ISSN: 1432-0983
    Keywords: Yeast ; Recombination ; Conversion ; Restoration
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    Notes: Summary Heteroduplex repair models of recombination predict that restoration of the parental genotype from heteroduplex will have the same frequency as conversion to the genotype of the homologue. We have reported previously (Savage and Hastings 1981) that the proportion of intragenic reciprocal events in the his1 locus of yeast is too low for this expectation. In this study, two classes of recombination event involving longer lengths of his1 are compared in a series of crosses using a constant right-hand marker. This comparison gives a value for conversion: restoration for the left-hand markers which is independant of the method used before. The values obtained by the two methods are significantly correlated, confirming that there is a disparity in the ratio of conversion to restoration, and that this disparity is seen as a deficiency of restoration for five alleles of his1.
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  • 70
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    Current genetics 8 (1984), S. 429-437 
    ISSN: 1432-0983
    Keywords: Yeast ; Heat-shock response ; Mitochondrial inhibition ; 2D electrophoresis
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    Topics: Biology
    Notes: Summary Conventional and two dimensional (2D) electrophoresis on ultrathin horizontal slab gels shows that heat shock proteins are synthesized and heat stroke proteins are curtailed after the transfer of Saccharomyces cerevisiae strain Z270 from 23 °C to 37 °C. Upon addition of the mitochondrial translation inhibitor erythromycin to cell cultures which incorporated labelled methionine at 23 °C, and after the transfer to 37 °C, we have shown that: a) in extracts of cells labelled at 23 °C, translational products sensitive to erythromycin could be observed on 2D gels; the synthesis of some of these proteins was enhanced, whereas the synthesis of some others declined when the labelling was carried out 20 min after the transfer to 37 °C; b) there are heat shock proteins whose induction at 37 °C was prevented by erythromycin; c) labelling of a number of proteins became weaker at 37 °C, but not at 23 °C, when this was done in the presence of erythromycin; d) two proteins were detectable only in samples labelled at 37 °C in the presence of erythromycin.
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  • 71
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    Keywords: Yeast ; Mitochondrial ochre mutations ; Specificity of suppressors ; Mitoribosomal misreading ; Intron-encoded maturases
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    Notes: Summary We describe studies on the action spectra of the mitochondrial suppressor mim3-1 and the three alleles of nuclear suppressor nam3. Their specificity of action was tested on 516 mit − mutations located in different mitochondrial genes. The degree of suppression was quantified by the extent of cytochrome oxidase and cytochrome b synthesis. We show that the four suppressors are allele-specific gene-nonspecific informational suppressors. They would act by changing the structure of the small mitoribosomal subunit which would decrease fidelity of translation enabling misreading of some but not all ochre codons. The implications of the results on the role of intron encoded maturases are discussed.
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  • 72
    ISSN: 1432-0983
    Keywords: Yeast ; Mitochondrial ochre mutations ; Nuclear informational suppressors ; Mitochondrial informational suppressors
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    Notes: Summary A systematic search for suppressors of mutations which cause a deficiency in the splicing of mitochondrial RNA has been undertaken. These splicing mutations were localized in the mRNA-maturase coding sequence of the second intron of the cob-boxgene, i.e. in the box3locus. A total of 953 revertants (mostly spontaneous in origin) were isolated and their genetic nature (nuclear vs. mitochondrial) and phenotype characterized. Most revertants were mitochondrially determined and displayed a wild-type phenotype. A mitochondrial suppressor unlinked with the box3 −target mutation was uncovered among the revertants displaying a pseudo-wild phenotype: out of 26 revertants analyzed, derived from 7 different box3− mutants only one such suppressor mutation mim3-1 was found. It was localized by rho− deletion mapping in the region between the oxi2 and oxi3 gene, within (or in the vicinity) the gene specifying the 15S ribosomal RNA. Nuclear suppressors were isolated from seven different box3 −mutants. All were recessive and had a pseudo-wild phenotype. Three such suppressors nam3-1, nam3-2 and nam3-3 were investigated more extensively. Tetrad analysis has shown that they are alleles of the same nuclear locus NAM3 and mitotic analysis has shown that they do not segregate mitotically.
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  • 73
    ISSN: 1432-072X
    Keywords: Mating tube ; Microtubule ; Tremella ; Ultrastructure ; Yeast
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    Topics: Biology
    Notes: Abstract Ultrastructure of the mating tube formed in yeast haplont of the heterobasidiomycete Tremella mesenterica was studied by electron microscopy. Cell wall of the mating tube emerged as evagination of the inner layers, rupturing outer layers of the mother cell wall. Comparison with budding cells suggested that the tube emergence place at bud scar and the process of tube emergence was the same as that of bud emergence. Electron transparent vesicles of 0.1 μm diameter were scattered in the cytoplasm of the mating tube. Nucleus-associated organelle was located at one side of the nuclear envelope which extended towards the mating tube. A few microtubules were detected in the mating tube, but their association with a nucleus was not clear. The cytoplasmic structure of the mating tube was discussed in comparison with that of hyphae of the filamentous fungi.
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  • 74
    ISSN: 1432-072X
    Keywords: Pyrophosphate ; Polymerie acid-soluble poly-phosphates ; Budding process ; Yeast
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    Topics: Biology
    Notes: Abstract In the cells of hybrid yeast strain Saccharomyces N.C.Y.C. 644 SU3 (Karlsberg collection), a large amount of pyrophosphate (30–300 μmol/g of dry weight) accumulates whatever the aeration conditions and the content of glucose in the medium. The content of pyrophosphate is 10–1000 times higher than that of ATP. At the early and mid-exponential growth phases two maxima of pyrophosphate accumulation are observable. The periods of maximal pyrophosphate accumulation in yeast coincide with those of the minimal content of polymeric acid-soluble polyphosphates and intense budding. In the light of the data obtained, the question is discussed as to the relationship between the metabolism of pyrophosphates and acid-soluble polyphosphates in yeast.
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  • 75
    ISSN: 1432-072X
    Keywords: Germination ; Glycogen ; Outgrowth ; Schizosaccharomyces pombe ; Spore ; Trehatase ; Trehalose ; Yeast
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    Notes: Abstract Quantitative changes in various carbohydrates of Schizosaccharomyces, pombe spores during germination and outgrowth were studied. Trehalose decreased rapidly, shortly after onset of germination, while glycogen remained constant throughout germination and outgrowth. Alkali-insoluble carbohydrates decreased after the lag period of about 40 min. The content of alkali-soluble carbohydrates was constant during germination, but increased remarkably in parallel with germtube formation. The mechanism of rapid degradation of trehalose during germination was also studied. The activity of trehalase (EC 3.2.1.28) was detected only in the cell wall fraction of isolated spores. Trehalase activity in the cell wall fraction was not enhanced during germination. Trehalose was not found in the isolated spore walls, but in the soluble fraction. These facts strongly suggested that trehalose, and trehalase were spatially separated in dormant spores and that trehalase became accessible to trehalose upon germination.
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  • 76
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    Archives of microbiology 129 (1981), S. 47-48 
    ISSN: 1432-072X
    Keywords: Adenylate energy charge ; Phosphate ; Saccharomyces ; Sporulation ; Yeast
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    Notes: Abstract The induction of sporulation in yeast is generally accompanied by a sharp increase in energy metabolism which is evidenced by a rise of the adenylate energy charge by that time. The energy charge can be held at a low level by limitation of the phosphate supply in the growth medium. Ascus formation remains unaffected by this treatment. This suggests that the rise in ATP production normally encountered during early sporulation is not essential for the initiation of sporulation.
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  • 77
    ISSN: 1432-072X
    Keywords: Ions ; Concentration ; Regulation ; Cytoplasm ; Vacuole ; Yeast ; Saccharomyces carlsbergensis
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    Notes: Abstract Intracellular distributions of K+, Mg2+ and orthophosphate under various conditions of cultivation or incubation of the yeast Saccharomyces carlsbergensis were studied by differential extraction of ion pools. The decisive role of vacuolar compartmentation of ions in regulation of K+, Mg2+ and orthophosphate levels in the yeast cytoplasm was shown. The content of intracellular K+ and Mg2+ in yeast increased or decreased primarily depending on the increase or decrease in the vacuolar ion pool. The levels of K+ and Mg2+ in the cytoplasm were practically unchanged. Vacuoles were involved in regulation of Mn2+ concentration in the cytoplasm of the yeast S. carlsbergensis accumulating this ion in the presence of glucose. Alongside the vacuolar compartmentation, the chemical compartmentation, i. e. formation of bound Mg2+, Mn2+ and K+ was, evidently, also involved in the control of ion levels in the cytoplasm. The orthophosphate level in the yeast cytoplasm was regulated by its accumulation in vacuoles and biosynthesis of inorganic polyphosphates in these organelles. The biosynthesis of low-molecular weight polyphosphates occurred parallel to the accumulation of Mg2+ or Mn2+ in vacuoles, thus confirming the availability of the other mechanism for the transport of these ions through the tonoplast differing from the transport mechanism through the plasmalemma.
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  • 78
    ISSN: 1432-072X
    Keywords: Yeast ; Phosphate uptake ; Phosphate-binding protein ; Anti-phosphate-binding protein antibodies
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    Notes: Abstract The purification of a phosphate-binding protein (PiBP2) by immunoadsorption is described. The entire anti phosphate-binding protein 2 antibodies as well as the Fab fragments obtained from these antibodies inhibit Pi uptake by whole cells. The inhibition is a mixed type of inhibition (V m and K m are affected). These results should be regarded as a possible involvement of phosphate-binding protein 2 in Pi uptake. The binding of 125I-labelled fragments prepared from anti phosphate-binding protein 2 antibodies to whole cells, to shocked cells and to protoplasts has been investigated. The results confirm the release of phosphate-binding protein by osmotic shock and during protoplast formation. From these findings, a cell-wall localisation, near the cell surface of the phosphate-binding protein should be proposed.
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  • 79
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    Archives of microbiology 137 (1984), S. 357-361 
    ISSN: 1432-072X
    Keywords: Yeast ; Saccharomyces cerevisiae ; Killer toxin ; Extracellular glycoprotein
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    Topics: Biology
    Notes: Abstract A total of 13 killer toxin producing strains belonging to the genera Saccharomyces, Candida and Pichia were tested against each other and against a sensitive yeast strain. Based on the activity of the toxins 4 different toxins of Saccharomyces cerevisiae, 2 different toxins of Pichia and one toxin of Candida were recognized. The culture filtrate of Pichia and Candida showed a much smaller activity than the strains of Saccharomyces. Extracellular killer toxins of 3 types of Saccharomyces were concentrated and partially purified. The pH optimum and the isoelectric point were determined. The killer toxins of S. cerevisiae strain NCYC 738, strain 399 and strain 28 were glycoproteins and had a molecular weight of Mr=16,000. The amino acid composition of the toxin type K2 of S. cerevisiae strain 399 was determined and compared with the composition of two other toxins.
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  • 80
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    Archives of microbiology 138 (1984), S. 183-186 
    ISSN: 1432-072X
    Keywords: Yeast ; Nitrogen assimilation ; Nitrate reductase ; Nitrite reductase ; Candida utilis ; Food yeast ; Nitrate reduction ; Nitrogenous oxide
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    Topics: Biology
    Notes: Abstract Assimilation of nitrate and various other inorganic nitrogen compounds by different yeasts was investigated. Nitrate, nitrite, hydroxylamine, hydrazine, ammonium sulphate, urea and L-asparagine were tested as sole sources of nitrogen for the growth of Candida albicans, C. pelliculosa, Debaryomyces hansenii, Saccharomyces cerevisiae, C. tropicalis, and C. utilis. Ammonium sulphate and L-asparagine supported the growth of all the yeasts tested except D. hansenii while hydroxylamine and hydrazine failed to support the growth of any. Nitrate and nitrite were assimilated only by C. utilis. Nitrate utilization by C. utilis was also accompanied by the enzymatic activities of NAD(P)H: nitrate oxidoreductase (EC 1.6.6.2) and NAD(P)H: nitrite oxidoreductase (EC 1.6.6.4), but not reduced methyl viologen-or FAD-nitrate oxidoreductases (EC 1.7.99.4). It is demonstrated here that nitrate and nitrite reductase activities are responsible for the ability of C. utilis to assimilate primary nitrogen.
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  • 81
    ISSN: 1432-072X
    Keywords: Peroxisome ; Methanol ; Methylamine ; Yeast ; Hansenula polymorpha ; Alcohol oxidase ; Amino oxidase ; Catalase ; Catabolite inactivation ; Turnover ; Cytochemical localization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth of Hansenula polymorpha in shake flasks and chemostat cultures in the presence of methanol as the sole source of carbon and methylamine as the sole source of nitrogen was associated with the development of peroxisomes in the cells. The organelles were involved in the concurrent oxidation of these two compounds, since they contained both alcohol oxidase and amine oxidase, which are key enzymes in methanol and methylamine metabolism, respectively. In addition catalase was present. Peroxisomes with a completely crystalline substructure were observed in methanol-limited chemostat-grown cells. Amine oxidase probably formed an integral part of these crystalloids, whereas catalase was present in a freely diffusable form. Transfer of cells, grown in a methanol-limited chemostat in the presence of methylamine into glucose/ammonium sulphate media resulted in the loss of both alcohol oxidase and amine oxidase activity from the cells. This process was associated with degradation of the crystalline peroxisomes. However, when cells were transferred into glucose/methylamine media, amine oxidase activity only declined during 2 h after the transfer and thereafter increased again. This subsequent rise in amine oxidase activity was associated with the development of new peroxisomes in the cells in which degradation of the crystalline peroxisomes, originally present, continued. These newly formed organelles probably originated from peroxisomes which had not been affected by degradation. When in the methanollimited chemostat methylamine was replaced by ammonium sulphate, repression of the synthesis of amine oxidase was observed. However, inactivation of this enzyme or degradation of peroxisomes was not detected. The decrease of amine oxidase activity in the culture was accounted for by dilution of enzyme as a result of growth and washout.
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  • 82
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    Archives of microbiology 137 (1984), S. 104-108 
    ISSN: 1432-072X
    Keywords: Chloroquine ; Yeast ; Proteolysis ; ATP hydrolysis ; Glucose consumption ; Ethanol formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In yeast cells, degradation of cellular proteins was inhibited by addition of chloroquine to the medium as shown by a decrease of the release of trichloroacetic acid-soluble radioactivity from prelabelled cell protein. Penetration of chloroquine into the cells was strongly enhanced with increasing pH value of the medium. The concentration in the cells reached 5–14 times that in the medium of pH 8.0. Fluorescence microscopy showed that chloroquine was concentrated in the vacuoles of the cells. Chloroquine, at concentrations attained in the cells, inhibited the activities of vacuolar proteinases in vitro. Furthermore, chloroquine caused a rapid and drastic decrease of the ATP content of the cells and prevented the fermentation of glucose and formation of ethanol under aerobic conditions.
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  • 83
    ISSN: 1432-072X
    Keywords: Agglutination substance ; Cell-cell recognition ; Glycoprotein ; Mating ; Saccharomyces cerevisiae ; Sexual agglutinability ; Yeast
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    Topics: Biology
    Notes: Abstract An a-mating-type-specific substance responsible for sexual agglutination was purified to 397-times in specific activity (units/mg protein) from the cytoplasm of a-mating type cells. The purified substance gave a single band stained with PAS reagent but not with both Coomassie brilliant blue and silver staining reagent by polyacrylamide gel electrophoresis in the presence of 8 M urea. However, incorporation of [35S]methionine and Lowry reaction clearly indicate that the substance is a glycoprotein. The substance specifically masked sexual agglutinability of cells of the opposite mating type α, indicating univalent action. The substance is a glycoprotein with a carbohydrate content of 90%, a pI of 4.5, and a molecular weight of 130,000. The substance was inactivated by 2-mercaptoethanol and proteolytic enzymes but not by glycolytic enzymes. The substance formed a complementary complex having no biological activity when mixed with α-agglutination substance from the wall or cytoplasm of α-cells in vitro.
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  • 84
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    Archives of microbiology 131 (1982), S. 298-301 
    ISSN: 1432-072X
    Keywords: Yeast ; Protoplast ; Compartmentation ; Vacuole ; Trehalose ; Trehalase ; Carbohydrate metabolism ; Saccharomyces cerevisiae
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    Notes: Abstract Protoplasts of Saccharomyces cerevisiae synthesized and degraded trehalose when they were incubated in a medium containing traces of glucose and acetate. Such protoplasts were gently lyzed by the polybase method and a particulate and soluble fraction was prepared. Trehalose was found in the soluble fraction and the trehalase activity mostly in the particulate fraction which also contained the vacuoles besides other cell organelles. Upon purification of the vacuoles, by density gradient centrifugation, the specific activity of trehalase increased parallel to the specific content of vacuolar markers. This indicates that trehalose is located in the cytosol and trehalase in the vacuole. It is suggested that trehalose, in addition to its role as a reserve may also function as a protective agent to maintain the cytosolic structure under conditions of stress.
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  • 85
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    Archives of microbiology 132 (1982), S. 144-148 
    ISSN: 1432-072X
    Keywords: Yeast ; Cell wall ; Mannoproteins ; Envelope turnover ; Concanavalin A
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    Topics: Biology
    Notes: Abstract By pulse and chase labeling experiments, two independent mannoprotein pools have been found associated with the Saccharomyces cerevisiae envelope. One of them probably corresponds to mannoproteins localized in the periplasmic space. These molecules showed a high turnover rate at 28° C. The second pool is formed by intrinsic wall mannoproteins which are apparently stable for long periods of time, after a small initial turnover. These results suggest that at least part of the mannoproteins initially found in the periplasmic space may move into the wall. The time lag between the addition of the radioactive precursors and their incorporation in the cell envelope (20–30 min for amino acids and about 10 min for carbohydrate) indicates that protein formation and carbohydrate incorporation take place in succession. Moreover, bulk glycosylation of mannoproteins seems to occur close in time to the moment of secretion into the periplasmic space.
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  • 86
    ISSN: 1432-072X
    Keywords: Carbon catabolite inactivation ; Yeast ; Malate dehydrogenase ; Fructose-1,6-bisphosphatase ; Glycolytic block mutants
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    Topics: Biology
    Notes: Abstract Experimental conditions have been elaborated to test for reversibility of the malate dehydrogenase inactivation (E.C.1.1.1.37) after addition of glucose to derepressed yeast cells. Malate dehydrogenase inactivation was shown to be irreversible at all stages of inactivation. In contrast fructose-1,6-bisphosphatase inactivation (E.C.3.1.11) remained reversible for at least 30 min after addition of glucose. Rapid reversible inactivation of fructose-1,6-bisphosphatase and irreversible inactivation of malate dehydrogenase were additionally investigated in glycolytic block mutants. Normal inactivation kinetics were observed in mutants without catalytic activity of phosphoglucoseisomerase (E.C.5.3.1.9), phosphofructokinase (E.C.2.7.1.11), triosephosphate isomerase (E.C.5.3.1.1) and phosphoglycerate kinase (E.C.2.7.2.3). Hence, neither type of inactivation depended on the accumulation of any glucose metabolite beyond glucose-6-phosphate. Under anaerobic conditions irreversible inactivation was completely abolished in glycolytic block mutants. In contrast rapid reversible inactivation was independent of energy provided by respiration or fermentation. Reversibility of fructose-1,6-bisphosphatase inactivation was tested under conditions which prevented irreversible malate dehydrogenase inactivation. In these experiments, fructose-1,6-bisphosphatase inactivation remained reversible for at least 120 min, whereas reversibility was normally restricted to about 30 min. This indicated a common mechanism between the irreversible part of fructose-1,6-bisphosphatase inactivation and irreversible malate dehydrogenase inactivation.
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  • 87
    ISSN: 1432-072X
    Keywords: Induction ; Catabolic repression ; galactose metabolism ; Yeast
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    Topics: Biology
    Notes: Abstract Induction and repression kinetics of alphagalactosidase, galactose uptake system and Leloir pathway enzymes were studied in chemostat cultures by changing the medium feed from glucose (11 mM) to glucose and galactose (11 mM; 17 mM respectively) in the induction experiments; and from galactose (11 mM) or (111 mM) to galactose plus glucose (83 mM) in the repression experiments. Basal levels of alpha-galactosidase and glucose uptake could be estimated in glucose-limited yeast cells, but it was not possible to detect any glactose pathway enzyme activity. In the repression experiments under galactose-limited or galactose-sufficient yeast cells, alpha-galactosidase and galactokinase decayed with K d=-0.21h-1=-D; that is, synthesis of these enzymes ceased (catabolite repression). In contrast transferase and epimerase activities and galactose uptake, decreased with K d values of-0.33 and-0.54h-1, showing that these activities were also subject to catabolite inactivation.
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  • 88
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    Archives of microbiology 124 (1980), S. 285-287 
    ISSN: 1432-072X
    Keywords: Yeast ; Saccharomyces cerevisiae ; Heat killing ; Membrane damage ; Genetic damage ; Growth temperature
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    Topics: Biology
    Notes: Abstract The resistance of exponentially growing yeast cells to killing by exposure to 52°C increased markedly as the growth temperature was increased. Identical killing curves were obtained for cells suspended in growth medium or in 0.9% saline. Cells resistant to killing at 52°C were quite sensitive to killing at slightly higher temperatures. These results suggest a primary role for membrane damage in the mechanism of heat killing.
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  • 89
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    Archives of microbiology 133 (1982), S. 155-161 
    ISSN: 1432-072X
    Keywords: Microtubule ; Nocodazole ; Yeast ; Cell cycle ; Dimorphism ; Fungus ; Wangiella dermatitidis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The microtubule inhibitor nocodazole {methyl-5-[2-(thienylcarbonyl)-1H-benzimidazol-2-yl]-carbamate} prevented nuclear migration and nuclear division in yeasts and developing multicellular forms of the polymorphic fungus Wangiella dermatitidis. It did not prevent yeast bud formation during at least two or three budding cycles, and caused yeasts to accumulate as premitotic forms with one to three buds. The effects of the drug suggested that at least three control pathways were involved in the yeast cell cycle; that the nocodazole block point was separate from the execution points of two temperature-sensitive mutations which lead to multicellularity; and that microtubules were controlling neither the yeast budding process nor the development of multicellular forms.
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  • 90
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    Archives of microbiology 133 (1982), S. 131-136 
    ISSN: 1432-072X
    Keywords: Fructose-bisphosphatase deficient mutants ; Yeast ; Schizosaccharomyces pombe ; Gluconeogenesis ; Glucose repression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We showed that in the yeast Schizosaccharomyces pombe, fructose-bisphosphatase is not subject to catabolite inactivation as it was observed in Saccharomyces cerevisiae. However, this enzyme activity is sensitive to catabolite repression in both yeasts. Two mutants lacking completely fructose-bisphosphatase activity were found. They were unable to grow on glycerol medium. They were still respiratory competent and exhibited the ability to derepress partially malate dehydrogenase activity. In glucose exponential phase culture, the parental strain lacks completely the fructosebisphosphatase activity due to catabolite repression. In these conditions, the growth is slowed down only in the mutants eventhough both mutants and their parental strain lack this enzyme activity. Normal sporulation and poor spore germination were observed for one mutant whereas, only in the presence of glucose, normal sporulation and normal spore germination were observed for the second mutant. Mendelian segregation of glycerol growth was found for the well germinating mutant. It is of nuclear heredity. The two mutations appeared to be closely linked.
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  • 91
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    Archives of microbiology 134 (1983), S. 270-275 
    ISSN: 1432-072X
    Keywords: Candida utilis ; Brettanomyces intermedius ; Yeast ; Glycolysis ; Vacuole ; Cytoplasm ; Phosphate compartmentation ; Phosphate transport ; Polyphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 31P NMR was used to study the dynamics of phosphate pools during substrate utilization by aerobic and anaerobic suspensions of the yeast Candida utilis and by aerobic suspensions of the yeast Brettanomyces intermedius. In both yeast, the cytoplasmic pH was monitored; in C. utilis also the vacuolar pH could be measured. When glucose was used as a substrate for C. utilis, the vacuolar store of inorganic phosphorus (both orthophosphate and polyphosphate) was mobilized to replenish cytoplasmic phosphate which had become very low due to the build-up of high sugar phosphate levels. The hydrolysis of polyphosphate was glucose-dependent; it did not occur with ethanol as the substrate. After glucose depletion resynthesis of polyphosphate occurred only under aerobic conditions; anaerobic C. utilis cells continued to hydrolyze vacuolar polyphosphate. This difference between the aerobic and anaerobic suspension could be related to differences in cellular ATP levels. When ethanol was employed as a substrate, both Candida utilis and Brettanomyces intermedius exhibited a substantial increase in polyphosphate levels. These observations suggested a dual role for polyphosphate in yeasts both as a phosphate and an energy store. The cytoplasmic pH in C. utilis displayed characteristic responses to metabolic changes during glucose degradation. B. intermedius experienced a strong cytoplasmic acidification upon ethanol utilization due to acetic acid formation. The mechanism of transport of Pi across the vacuolar membrane in C. utilis appeared to be different from that reported for the plasma membrane.
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  • 92
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    Archives of microbiology 130 (1981), S. 87-89 
    ISSN: 1432-072X
    Keywords: Yeast ; Kluyveromyces ; 6-Deoxyglucose ; Glucose transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The inducible glucose transport system of the yeast, Kluyveromyces lactis, was studied using the nonmetabolizeable glucose analogue, 6-deoxyglucose. The free sugar analogue is transported into glucose-grown cells via a facilitated diffusion system as determined by the nonconcentrative uptake of the sugar analogue, by the failure of energy inhibitors to reduce the rate of transport and by exchange diffusion across the membrane. Free 6-deoxyglucose is also transported into succinate-grown cells passively. Induction experiments revealed that 6-deoxyglucose serves as a gratuitous inducer for the glucose transport system in this yeast.
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  • 93
    ISSN: 1573-1561
    Keywords: Spruce budworm ; Choristoneura fumiferana ; Lepidoptera ; Tortricidae ; sex pheromone ; small-tree thinnings ; temperature ; precipitation ; wind ; attraction distance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mean catches of spruce budworm,Choristoneura fumiferana (Clemens), moths were not significantly different among four small-tree thinning treatments of young spruce-fir-hemlock regeneration. Significant inverse relationships were found between trap catches and distances to nearby spruce-fir-hemlock overstory. Prevailing wind directions indicated that moths were attracted anemotactically to upwind pheromone sources. No definite trends were detected between catches and temperature or precipitation.
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  • 94
    ISSN: 1573-1561
    Keywords: Kairomone ; 2-acylcyclohexane-1,3-diones ; ovipositionEphestia kuehniella Zeller [syn.Anagasta kuehniella (Zeller)] ; Lepidoptera ; Pyralidae ; Nemeritis canenscens (Grav.) [syn.Venturia canescens (Grav.)] ; Hymenoptera ; Ichneumonidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relative activities of sixteen 2-acylcyclohexane-1,3-diones from the larval mandibular glands ofEphestia (=Anagasta) kuehniella Zeller in causing the parasiteNemeritis (=Venturia) canescens (Grav.) to make oviposition movements are reported.
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  • 95
    ISSN: 1573-1561
    Keywords: Resistance ; mating disruption ; sex pheromone ; (Z,Z)-7 ; 11-hexadecadienyl acetate ; (Z,E)-7 ; 11-hexadecadienyl acetate ; Lepidoptera ; Gelechiidae ; pink bollworm ; Pectinophora gossypiella ; cotton ; pheromone collection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract After an extensive examination of the release rates and blend ratios of pheromonal components emitted by field-collected femalePectinophora gossypiella (Saunders), we find no evidence of resistance to pheromones applied to cotton fields to disrupt mating. Females from fields with 3–5 years of exposure to disruptant pheromones as well as those from fields with only minimal exposure to disruptant pheromones emitted (Z,Z)-7,11-hexadecadienyl acetate at a rate of ca. 0.1 ng/min and (Z,E)7,11-hexadecadienyl acetate at ca. 0.06 ng/min. The ratio of pheromonal components was much less variable than the measured emission rate and was centered about a 61:39Z, Z to Z,E ratio. In contrast to the blend ratio emitted by females, the composition of the pheromonal blend used in monitoring populations and disrupting mating is centered about 50:50 Z,Z to Z.E. In general there was a remarkable consistency in the release rate and blend ratio among populations of females throughout southern California and those from a laboratory colony. It would appear that, although resistance to theP. gossypiella pheromone is still a very real possibility when it is used heavily in pest management as a mating disruptant, there are current agricultural practices and conditions which would hinder its development.
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  • 96
    ISSN: 1573-1561
    Keywords: Structure-activity relationships ; single-cell recordings ; turnip moth ; Agrotis segetum ; Lepidoptera ; Noctuidae ; molecular shape ; dipole moments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The response of an antennal receptor cell of the turnip moth,Agrotis segetum, was recorded during stimulation with a series of (Z)-7-dodecenyl acetate analogs with structural variations of the acetate group. The investigated receptor cell is known to be highly selective to (Z)-7-dodecenyl acetate. All parts of the acetate group were found to be of great importance for full biological activity. The results indicate very strict requirements on the shape of the polar functional group, as well as on its electron distribution for a successful interaction with the antennal receptor cell.
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  • 97
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; Lepidoptera ; Danaidae ; monarch butterflies ; Asdepias speciosa ; Asclepiadaceae ; milkweeds ; ecological chemistry ; plant-insect interactions ; chemical ecology ; chemical defense ; coevolution ; thin-layer chromatography ; cardenolide fingerprints ; cardenolides ; cardiac glycosides ; desglucosyrioside ; labriformin ; labriformidin ; syriogenin ; uzarigenin ; emetic potency ; emesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The pattern of variation in gross cardenolide concentration of 111Asclepias speciosa plants collected in six different areas of California is a positively skewed distribution which ranges from 19 to 344 μg of cardenolide per 0.1 g dry weight with a mean of 90 μg per 0.1 g. Butterflies reared individually on these plants in their native habitats ranged from 41 to 547 μg of cardenolide per 0.1 g dry weight with a mean of 179 μg. Total cardenolide per butterfly ranged from 54 to 1279 μg with a mean of 319 μg. Differences in concentrations and total cardenolide contents in the butterflies from the six geographic areas appeared minor, and there were no differences between the males and the females, although the males did weigh significantly more than females. The uptake of cardenolide by the butterflies was found to be a logarithmic function of the plant concentration. This results in regulation: larvae which feed on low-concentration plants produce butterflies with increased cardenolide concentrations relative to those of the plants, and those which feed on high-concentration plants produce butterflies with decreased concentrations. No evidence was adduced that high concentrations of cardenolides in the plants affected the fitness of the butterflies. The mean emetic potencies of the powdered plant and butterfly material were 5.62 and 5.25 blue jay emetic dose fifty units per milligram of cardenolide and the number of ED50 units per butterfly ranged from 0.28 to 6.7 with a mean of 1.67. Monarchs reared onA. speciosa, on average, are only about one tenth as emetic as those reared onA. eriocarpa. UnlikeA. eriocarpa which is limited to California,A. speciosa ranges from California to the Great Plains and is replaced eastwards byA. syriaca L. These two latter milkweed species appear to have a similar array of chemically identical cardenolides, and therefore both must produce butterflies of relatively low emetic potency to birds, with important ecological implications. About 80% of the lower emetic potency of monarchs reared on A. speciosa compared to those reared onA. eriocarpa appears attributable to the higher polarity of the cardenolides inA. speciosa. Thin-layer Chromatographie separation of the cardenolides in two different solvent systems showed that there are 23 cardenolides in theA. speciosa plants of which 20 are stored by the butterflies. There were no differences in the cardenolide spot patterns due either to geographic origin or the sex of the butterflies. As when reared onA. eriocarpa, the butterflies did not store the plant cardenolides withR f values greater than digitoxigenin. However, metabolic transformation of the cardenolides by the larvae appeared minor in comparison to when they were reared onA. eriocarpa. AlthoughA. eriocarpa andA. speciosa contain similar numbers of cardenolides and both contain desglucosyrioside, the cardenolides ofA. speciosa overall are more polar. ThusA. speciosa has no or only small amounts of the nonpolar labriformin and labriformidin, whereas both occur in high concentrations inA. eriocarpa. A. speciosa plants and butterflies also contain uzarigen, syriogenin, and possibly other polar cardenolides withR f values lower than digitoxin. The cardenolide concentration in the leaves is not only considerably less than inA. eriocarpa, but the latex has little to immeasurable cardenolide, whereas that ofA. eriocarpa has very high concentrations of several cardenolides. Quantitative analysis ofR f values of the cardenolide spots, their intensities, and their probabilities of occurrence in the chloroform-methanol-formamide TLC system produced a cardenolide fingerprint pattern very different from that previously established for monarchs reared onA. eriocarpa. This dispels recently published skepticism about the predictibility of chemical fingerprints based upon ingested secondary plant chemicals.
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  • 98
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    Journal of chemical ecology 10 (1984), S. 945-956 
    ISSN: 1573-1561
    Keywords: Cardenolide ; uscharidin ; metabolism ; monarch butterfly ; Danaus plexippus ; Lepidoptera ; Danaidae ; milkweed ; Asclepias ; N-demethylation ; mixed function oxidase ; monooxygenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Midgut and fat body homogenates of monarch butterfly larvae,Danaus plexippus L. (Lepidoptera:Danaidae), were examined for microsomal monooxygenase activity usingp-chloro-N-methylanilineN-demethylation and for the ability to metabolize a milkweed (Asclepias spp.) cardenolide (C23 steroid glycoside), uscharidin. All homogenates tested had bothN-demethylation and uscharidin biotransformation activities. Both transformations required NADPH. The monooxygenase inhibitors sesamex, SKF525A, and carbon monoxide inhibitedN-demethylation but not uscharidin biotransformation. Subsequent subcellular fractionation revealed the uscharidin biotransformation occurs in the soluble fraction and not the microsomal fraction, whileN-demethylation occurs in the microsomal fraction and not the soluble fraction. The larval NADPH-dependent microsomal monooxygenase apparently is not involved in the metabolism of uscharidin.
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  • 99
    ISSN: 1573-1561
    Keywords: Oriental fruit moth ; orfralure ; sex pheromone ; traps ; air permeation with pheromone ; Lepidoptera ; Olethreutinae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Orfralure [93% (Z), 7% (E)-8-dodecen-1-ol acetate], the synthetic pheromone of the oriental fruit moth,Grapholitha molesta (Busck), was released into the air of orchard test plots either by hanging plastic laminated dispensers on trees or by aerial dispersal of microcapsules containing a solution of the lure. Trap catch was reduced 95% or more with the most effective formulations, but consistently higher reductions were produced by the dispensers. In tests as long as 28 weeks with dispensers, a single retreatment at midseason maintained an effective concentration.
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  • 100
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    Journal of chemical ecology 6 (1980), S. 213-220 
    ISSN: 1573-1561
    Keywords: Olfactory receptors ; chemoreception ; Lepidoptera ; Lasio-campidae ; plant volatiles ; tent caterpillars ; Malacosoma americanum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Volatile constituents of leaves of acceptable and unacceptable plants evoke multiunit responses from the antennal olfactory sensilla of larvae of the eastern tent caterpillar. Electrophysiological investigation of the activities of three of the sixteen antennal olfactory receptors revealed that different combinations of the three responded to the various plants. In those instances where the same combination responded to more than one species of plant, the ratios of responses measured as frequency of action potentials were often different. Thus, discrimination of different plants theoretically could be based upon the absolute number of cells responding and/or the ratios of frequencies.
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