ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Artikel  (761)
  • Coleoptera  (315)
  • Saccharomyces cerevisiae  (307)
  • 42.55
  • Chemical Engineering
  • Electronic structure and strongly correlated systems
  • Springer  (761)
  • 1990-1994  (492)
  • 1980-1984  (269)
Sammlung
  • Artikel  (761)
Schlagwörter
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 71 (1994), S. 201-209 
    ISSN: 1570-7458
    Schlagwort(e): Hypothenemus hampei ; coffee berry borer ; abiotic mortality ; Coleoptera ; Scolytidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mortality of the coffee berry borer was studied under controlled laboratory conditions in Tapachula, Mexico. For adult female borers subjected to a range of relative humidities (RH) without food at 25°C, the longest mean survival time (20 days) was obtained at 93.5% RH. Adult borer survival was also studied at a range of temperatures for a fixed relative humidity (93.5% RH); at 20°C mean survival time was 28 days. Fecundity and mortality of borer stages in berries was studied for a range of humidities at 25°C. Maximum fecundity was obtained at 90 and 93.5% RH. Immature stages were ejected from the berry at 84% RH and above, which is interpreted as a form of brood hygiene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 72 (1994), S. 255-263 
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Chrysomelidae ; Leptinotarsa decemlineata ; behavior ; thermal biology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In short-term field trials at combinations of ambient temperature (°C) and insolation (W·m−2), larval Colorado potato beetles (Leptinotarsa decemlineata [Say] [Coleoptera: Chrysomelidae]) were observed after their release on the adaxial surface of leaflets on potato plants (Solanum tuberosum L. Solanaceae). The larvae either began feeding or moved under the leaflet; mean interval from release to expression of these behaviors (2.9±0.05 min [n =358]) was independent of air temperature and insolation. Proportion of larvae moving under the leaflet increased logistically with both air temperature and insolation. A 1 W·m−2 change in insolation (P) evoked the same effect on this proportion as a 0.0838 °C change in air temperature (T a ), so the two quantities were combined as T*=T a +P·0.0838 °C/(W·m−2), which has units of °C. The proportion of larvae moving under the leaflet increased logistically with T*. In 1-day field trials we monitored air temperature, insolation and proportion of larvae under the leaflet, and compared the latter to predictions from the logistic regression derived from the short-term trials. Consistently more larvae occurred under leaflets than predicted from the logistic regression; this bias diminished as T* increased until at T*≥40 °C, observed and predicted proportions were equal. This pattern of deviation from the predictions of the logistic regression is consistent with a thermoregulatory strategy in which larvae move away from hostile conditions, rather than seek optimal conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 71 (1994), S. 177-180 
    ISSN: 1570-7458
    Schlagwort(e): aflatoxin ; Carophilus ; Zea mays ; corn ; plant resistance ; Coleoptera ; Nitidulidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 70 (1994), S. 217-225 
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Chrysomelidae ; Leptinotarsa decemlineata ; Colorado potato beetle ; Solanaceae ; Solanum berthaultii ; plant resistance ; glandular trichomes ; host preference ; behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Choice and no-choice studies were conducted to determine how the glandular trichomes of the wild potato,Solanum berthaultii Hawkes, affect host preference of the Colorado potato beetle,Leptinotarsa decemlineata (Say). Given a feeding choice betweenS. tuberosum andS. berthaultii, larvae and adults preferred the foliage ofS. tuberosum, but adults were more discriminating. When foliage ofS. berthaultii was appressed toS. tuberosum leaflets, fewer adults fed on the appressed leaflets. When given a choice between ‘trichome-intact’ and ‘trichome-removed’S. berthaultii foliage, adults preferred to feed on the latter. The preference for ‘trichome-removed’ foliage and the percent of adults initiating feeding, increased with the degree of trichome removal. These studies provide evidence that the resistance ofS. berthaultii is associated with feeding deterrents localized in the glandular trichomes, thatS. berthaultii possesses more than one mechanism of resistance to the Colorado potato beetle, and that the expression of resistance is dependent on the developmental stage of the insect.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 70 (1994), S. 201-208 
    ISSN: 1570-7458
    Schlagwort(e): Sitophilus oryzae ; S. zeamais ; Coleoptera ; Curculionidae ; flight activity ; symbiosis ; vitamin ; amino acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les performances de vol de nombreuses souches deSitophilus oryzae L. etS. zeamais Mots. (Coleoptera, Curculionidae) ont été comparées sur blé. Il s’avère que les mâles sont plus actifs que les femelles et queS. zeamais possède une meilleure aptitude au vol queS. oryzae. De plus, dans les deux espèces élevées sur blé, seuls les charançons normalement symbiotiques sont capables de voler, tandis que les aposymbiotiques ont perdu ce pouvoir. En complémentant la nourriture avec des vitamines (acide pantothénique et riboflavine) et certains acides aminés (phénylalanine et proline), cette activité a pu être restaurée en partie. L’influence de la symbiose sur l’aptitude au vol du charançon du genreSitophilus est commentée en fonction du métabolisme énergétique (coenzymes, proline) et du rôle joué par la symbiose dans ce comportement qui permet d’augmenter la dissémination de l’espèce.
    Notizen: Abstract The flight activity (take-off) of various strains ofSitophilus oryzae L. andS. zeamais Mots. (Coleoptera, Curculionidae) have been compared on wheat. It was shown that males are more active than females and thatS. zeamais, is more active thanS. oryzae. Furthermore, in the two species, when reared on wheat kernels, only symbiotic weevils were able to fly, while aposymbiotic insects did not. By supplementation of the diet with vitamins (pantothenic acid, riboflavin) and amino acids (phenylalanine and proline), this activity could be restored in part. The influence of symbiosis on the flight ability ofSitophilus weevil is discussed in relation to the energy metabolism (coenzymes, proline), the role played by symbiosis in this behaviour and its possible effect on the dissemination of the species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 73 (1994), S. 39-50 
    ISSN: 1570-7458
    Schlagwort(e): Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; distribution ; overwintering ; diapause ; cultural control ; trap cropping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Overwintering Colorado potato beetles (Leptinotarsa decemlineata (Say)) were concentrated primarily within woody borders, and mortality was lower in borders than in potato fields. After overwintering, only 15–44% of live beetles were in the potato fields. In experiments with small plots, colonization of fields from woody borders was reduced ∼60% by a trap crop, either treated with adulticide or with beetles collected daily. Such trap crops, or simply pitfall traps to prevent colonization from woody borders, could significantly reduce early-season adult numbers and subsequent larval populations. However, success is dependent on the local densities of overwintered beetles, and the prevalence of arrestment behavior in the case of trap crops.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Chrysomelidae ; Leptinotarsa decemlineata ; Colorado potato beetle ; Solanaceae ; Solanum berthaultii ; potato ; plant resistance ; selection ; adaptation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Thirty cohorts of the Colorado potato beetle (CPB) were reared for ten consecutive generations on the cultivated potato,Solanum tuberosum, and on two accessions (PI 473331 and PI 473334) of the resistant wild species,S. berthaultii. At each generation, selection was imposed for increased survival, decreased development time, and for increased fecundity. Although several parameters responded to selection, net replacement rate (R0) onS. berthaultii was consistently less than 1/3 that on cultivated potato. At the tenth generation, eachS. tuberosum strain female replaced herself with 110 daughters, whereas females from strains reared on PI 473334 and PI 473331 produced an average of 30 and 7 daughters, respectively. Slopes of the R0 regression lines for populations reared onS. tuberosum andS. berthaultii did not differ from zero, indicating no significant response to selection. Our findings suggest that populations of the Colorado potato beetle may have genetic variability in some performance traits for adaptation toS. berthaultii, but that adaptation is unlikely to occur as rapidly as previously reported.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    ISSN: 1572-8889
    Schlagwort(e): firefly ; entrainment ; insect communication ; Coleoptera ; aggressive mimicry ; bioluminescence ; Lampyridae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract FemalePhoturis versicolor fireflies attempt to capture males by responding to heterospecific flash patterns. A mating-dependent switch occurs which affects response timing and frequency of female flashes. We examined the switch using females of known age, mating status, and flash experience to assess how accurate mimicry is, what factors influence it, and what mechanism produces it. Presentations of simulated male flash patterns before and after mating revealed elements of an entrainment mechanism controlling female responsiveness. Unmated females preferentially answered conspecific patterns with variable latencies, averaging 1 s. Mating induced changes in both response frequency and response latency: Females answered heterospecific patterns more frequently, and latencies elicited by conspecific patterns shifted away from the unmated range. Heterogeneity in mean and variance of response latency among individuals indicates that females do not share a discrete reply to a given pattern. Little correspondence exists between latencies of sympatric species andP. versicolor females, suggesting that the flash response mechanism produces entriainment to any rhythmic pattern, not a one-to-one matching between prey and predator latencies. Different selective scenarios underlie strict mimicry versus entrainment mimicry.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    ISSN: 1572-8773
    Schlagwort(e): catalase ; copper resistance ; pH-dependent growth ; Saccharomyces cerevisiae ; superoxide dismutase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A strain of Saccharomyces cerevisiae has been adapted to increasing concentrations of copper at two different pH values. The growth curve at pH 5.5 is characterized by a time generation increasing with the amount of added copper. A significant decrease of cell volume as compared with the control is also observed. At pH 3 the cells grow faster than at pH 5.5 and resist higher copper concentrations (3.8 against 1.2 mm). Experimental evidence indicates that, after copper treatment, the metal is not bound to the cell wall, but is localized intracellularly. A significant precipitation of copper salts in the medium was observed only at pH 5.5. Increased levels of superoxide dismutase (SOD) activity were observed in copper-treated cells and which persisted after 20 subsequent inocula in a medium without added metal. On the contrary, catalase activity was not stimulated by copper treatment and, hence, not correlated with SOD levels. The mechanism of copper resistance, therefore, probably involves a persistent induction of SOD, but not of catalase, and it is strongly pH-dependent.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    ISSN: 1432-0649
    Schlagwort(e): 32.00 ; 42.55 ; 42.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract When mercury atoms, present with a buffer gas (N2 or Ar) in a quartz cell or in a graphite furnace are excited into the 73 S 1 level by means of two pulsed dye lasers tuned at 253.652 nm (61 S o → 63 P 1) and 435.835 nm (63 P 1 → 73 S 1), a laser-like, collimated emission is observed along the axis of the cell at the green mercury line (73 S 1 → 63 P 2), 546.074 nm). This radiation exhibits a pronounced non-linear dependence upon the number density of the mercury atoms in the cell. This behaviour is interpreted as being due to amplified spontaneous emission (ASE), which occurs as a result of the transient population inversion between the 7s 3 S 1 and 6p 3 P 2 o levels. The parameters governing the population inversion can be deduced by applying a rate equation analysis to the atomic system. A time-resolved observation of both ASE and spontaneous fluorescence signals confirms the totally different characteristics of the two emission processes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    ISSN: 1432-0649
    Schlagwort(e): 42.60.Lh ; 42.55 ; 42.70
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Three laser transitions (607.2 nm, 639.5 nm, 720.9 nm) in a flashlamp-pumped Pr3+:LiYF4 laser at room temperature are investigated. Cerium ions (Ce3+) doped into the fused-quartz envelope of the flashlamp efficiently transfer strong UV radiation from pumping light into the absorption region of Pr3+ ions (λ = 420−480 nm), so that the slope efficiency of all three laser emissions could be increased by almost 100% compared to excitation with a pure quartz flashlamp. At a pump energy of 30 J the output energy of these three laser emissions reached 4.7 mJ, 87 mJ and 30 mJ.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 543-546 
    ISSN: 1432-0649
    Schlagwort(e): 32.20 ; 42.55 ; 82.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The absolute concentration of atomic oxygen in an atmospheric pressure hydrogen/air flame has been measured using Intracavity Laser Spectroscopy (ICLS) based on a dye laser pumped by an argon-ion laser. Absorptions at the highly forbidden transitions at 630.030 nm and 636.380 nm were observed at an equivalent optical length of up to 10 km. The relatively low intensity of the dye laser avoids photochemical interferences that are inherent to some other methods for detecting atomic oxygen. The detection sensitivity is about 6 × 1014 atom/cm3 and can be improved with better flame and laser stabilization.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 58 (1994), S. 69-71 
    ISSN: 1432-0649
    Schlagwort(e): 42.55 ; 78.45
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We report the cw laser emission of Ho: YLF in an astigmatically compensated resonator under pumping by a laser diode array. We measured the laser efficiency at different operating temperatures of the crystal and the non-saturated gain coefficient at the peak wavelength of laser emission. The laser tunability extends from 2.040 µm to 2.075 µm.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 38 (1994), S. 363-368 
    ISSN: 1432-1432
    Schlagwort(e): Saccharomyces cerevisiae ; 2-μm circle ; DNA sequencing ; Horizontal transmission ; Site-specific recombination ; Selfish DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We compared the nucleotide substitution pattern over the entire genome of two unique variants of the 6,300-bp selfish DNA (2 μm) plasmid in Saccharomyces cerevisiae. The DNA sequence of the left-unique region is identical among 2-μm variants, while the right-unique region shows substantial divergence. This chimeric pattern cannot be explained by neutral or Darwinian selection models. We propose that horizontal transmission of the 2-μm plasmid coupled with a directed, polarized gene conversion maintains the DNA sequence of the left-unique region, whereas the right-unique region is subject to random drift and Darwinian selection.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 59 (1994), S. 289-293 
    ISSN: 1432-0630
    Schlagwort(e): 42.55 ; 81.40 ; 82.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Structure formation upon 500 fs 248 nm KrF-laser irradiation of PolyEthylene Terephthalate (PET) and PolyImide (PI) has been investigated. The results obtained with fs pulses have been compared to those with ns pulses.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    ISSN: 1423-0445
    Schlagwort(e): adult mortality ; oviposition inhibition ; larval mortality ; aromatic hydrodistillated and non hydrodistillated plants ; Coleoptera ; Bruchidae ; Acanthoscelides obtectus ; Lamiaceae ; Origanum ; Thymus ; Satureia ; Rosmarinus ; Mentha ; Myrtaceae ; Eucalyptus ; Lauraceae ; Laurus ; Poaceae ; Cymbopogon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    ISSN: 1423-0445
    Schlagwort(e): chemical defence ; sequestration ; reflex bleeding ; alkaloids ; chemotaxonomy ; biosynthesis ; repellency ; toxicity ; Coleoptera ; Coccinellidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The defensive mechanisms which protect ladybird beetles (Coccinellidae) against predators are reviewed. Besides behavioural mechanisms, such as thanatosis and reflex bleeding, chemical defence mechanisms are playing a prevalent role. Indeed, ladybirds are protected not only by their smell, but also by repulsive alkaloids, most of which are considered to be of autogenous origin. In a few cases, dietarily-acquired substances are also involved. Particular emphasis is laid on the repellent alkaloids which are contained in the haemolymph of many species. The structures of 34 nitrogen-containing compounds isolated so far are presented, and their distribution within the family is discussed in the light of the most widely accepted classification of these beetles. To conclude, the mode of release of the alkaloids, their variation through the life cycle and their repellent and toxic properties are discussed, as well as the few biosynthetic data yet available.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    ISSN: 1423-0445
    Schlagwort(e): oviposition ; repellents ; larval secretion ; Coleoptera ; Chrysomelidae ; Phaedon cochleariae ; Chrysomela lapponica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The exocrine glandular secretions of larvae of the subfamily Chrysomelinae are known to repel conspecific adults, other competitive phytophagous insects and natural enemies. InPhaedon cochleariae, the intraspecific activity of tlc fractions of the larval secretion was tested in order to examine the ecological significance of two fractions containing minor components and a fraction containing the major compound, the cyclopentanoid monoterpene (epi)chrysomelidial. InChrysomela lapponica, the defensive activity of the larval secretion against ants is known from specimens feeding upon willow or birch. The feeding preferences of larvae and adults ofC. lapponica from a Finnish and a Czech population were tested. The Finnish individuals significantly preferred feeding uponSalix borealis, whereas they hardly fed upon birch. The Czech specimens clearly preferred birch (Betula pubescens) to willow species. Application of salicin onto leaves of a willow species free of this phenolglycoside revealed that the Finnish individuals preferred feeding upon leaves with salicin. On the other hand, the Czech individuals avoided feeding upon leaves ofB. pubescens treated with salicin. The chemical composition of the glandular secretion of the Finnish larvae differed from the one of the Czech larvae. GC-MS-analyses of the secretions revealed that salicylaldehyde was the only major component of the secretion of Finnish larvae feeding upon the salicin-containing willowS. borealis. The glandular secretion of the Czech larvae feeding upon birch contained numerous esters of isobutyric acid and 2-methylbutyric acid. When Czech larvae had fed upon a salicin-containing willow (S. fragilis), the major compounds of their secretion were benzoic acid, salicylalcohol and benzoic acid esters; salicylaldehyde was only detected in traces. Thus,C. lapponica individuals from the Finland population adapted so closely to a salicincontaining willow that they clearly prefer this plant for food and that they obviously derive their main larval defensive compound (salicylaldehyde) from their host-plant.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 50 (1994), S. 766-770 
    ISSN: 1420-9071
    Schlagwort(e): Gastrophysa viridula ; Chrysomelidae ; Coleoptera ; chemical defence ; acetates ; hydrocarbons ; gas-liquid chromatography ; gas chromatography-mass spectrometry ; sexual dimorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The lipid fraction of the defensive secretion of adultGastrophysa viridula was analyzed by gas-liquid chromatography and gas chromatography-mass spectrometry. Three long chain acetates and two methyl-branched hydrocarbons were identified and their amounts in the secretion of single field-collected and laboratory-reared beetles determined. The composition of the secretion was affected by the sex, reproductive status, and age of the beetle. The ratio of (Z)-11-eicosenyl acetate to (Z)-13-docosenyl acetate ranged from 0.30 to 0.78 in male beetles and from 1.05 to 2.06 in female beetles. The biological significance of this sexual dimorphism is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 50 (1994), S. 853-856 
    ISSN: 1420-9071
    Schlagwort(e): Migdolus fryanus ; Coleoptera ; Cerambycidae ; N-2′-methylbutanoyl 2-methylbutylamine ; N-formyll-isoleucine methyl ester ; sex pheromone ; chiral resolution ; dose-response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The first known long-range female-released sex pheromone for the family Cerambycidae is reported fromMigdolus fryanus, a sugarcane pest in South America. Although two female-specific compounds, namely, N-(2′S)-methylbutanoyl 2-methylbutylamine and N-formyll-isoleucine methyl esters were identified, field tests with synthetic chemicals revealed that only the amide was active and that the amino acid derivative neither increased or decreased trap catches by the amide. This is the first identification of amide as a sex pheromone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 26 (1994), S. 95-99 
    ISSN: 1432-0983
    Schlagwort(e): Translational fidelity ; Paromomycin ; Stuttering ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Missense errors in the translation of mRNAs in Saccharomyces cerevisiae were screened by looking for charge heterogeneity of proteins on two-dimensional gels resulting from the substitution of charged and neutral amino acids. No such mistranslation was detected in wild-type yeast strains grown in the presence of the translational error-inducing antibiotic paromomycin. However, paromomycin-induced mistranslation of a heterologous mRNA, encoding human phosphoglycerate kinase expressed in yeast, was seen. We suggest that the combination of error-prone translation of a heterologous mRNA, and growth in the presence of paromomycin, leads to an accumulation of mistranslated proteins that can be detected by two-dimensional gel electrophoresis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    ISSN: 1432-0983
    Schlagwort(e): ABC superfamily ; Multidrug resistance ; Saccharomyces cerevisiae ; YDR1 gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A multidrug resistance gene, YDR1, of Saccharomyces cerevisiae, which encodes a 170-kDa protein of a member of the ABC superfamily, was identified. Disruption of YDR1 resulted in hypersensitivity to cycloheximide, cerulenin, compactin, staurosporine and fluphenazine, indicating that YDR1 is an important determinant of cross resistance to apparently-unrelated drugs. The Ydr1 protein bears the highest similarity to the S. cerevisiae Snq2 protein required for resistance to the mutagen 4-NQO. The drug-specificity analysis of YDR1 and SNQ2 by gene disruption, and its phenotypic suppression by the overexpressed genes, revealed overlapping, yet distinct, specificities. YDR1 was responsible for cycloheximide, cerulenin and compactin resistance, whereas, SNQ2 was responsible for 4-NQO resistance. The two genes had overlapping specificities toward staurosporine and fluphenazine. The transcription of YDR1 and SNQ2 was induced by various drugs, both relevant and irrelevant to the resistance caused by the gene, suggesting that drug specificity can be mainly attributed to the functional difference of the putative transporters. The transcription of these genes was also increased by heat shock. The yeast drug-resistance system provides a novel model for mammalian multidrug resistance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    ISSN: 1432-0983
    Schlagwort(e): Psoralen ; DNA repair mutants ; Gene conversion ; Recombination ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of the DNA repair genePSO3 on photoactivated psoralen-induced meiotic recombination, gene conversion, reverse mutation, and on survival, was assayed in diploid strains ofSaccharomyces cerevisiae homozygous for the wild-type or thepso3-1 mutant allele. Sporulation was normal in thepso3-1 diploid. Wild-type and mutant strains had the same sensitivity to photoactivated monofunctional psoralen (3-CPs+UVA) in meiosis-uncommitted and meiosis-committed stages. The mutant showed higher sensitivity to photoactivated bifunctional psoralen (8-MOP+UVA) during all stages of the meiotic cycle. Mutation induction by 3-CPs+UVA or 8-MOP+UVA in meiosis-committed cells revealed no significant differences between wild-type and thepso3-1 mutant. The status of thePSO3 gene has no influence on the kinetics of induction of gene conversion and crossing-over after 3-CPs+UVA treatment in meiosis-committed cells: gene conversion was blocked while recombination was induced. After treatment with 8-MOP+UVA gene conversion was also blocked in both strains while crossing-over could only be observed in meiosis-committed wild-type cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 25 (1994), S. 180-183 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; In-vivo cloning ; Non-replicative vectors ; Homologous recombination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have devised a new strategy to clone DNA sequences from an yeast autonomously-propagating plasmid into a non-autonomous integrative vector by in-vivo recombination. The method consists of a first step in which the replicative plasmid carrying the DNA fragment of interest forms a co-integrate with the non-replicative plasmid by an induced in-vivo reciprocal exchange accompanied by gene conversion. The dimeric plasmid obtained is then purified and cut with an appropriate restriction enzyme and ligated independently to obtain the two intact monomeric plasmids, the original autonomous plasmid plus the new non-autonomous plasmid carrying the subcloned DNA fragment. The dimeric co-integrate can also serve as substrate for a second in-vivo reciprocal exchange that produces new autonomous plasmids carrying the desired DNA fragment. The technique considerably expands the applications of in-vivo cloning in yeast by complementing three important characteristics of previously published methods: (1) it can be used to clone into non-propagating vectors; (2) co-transformation experiments are not required; and (3) the intermediate co-integrate can be used to generate new types of autonomously-propagating plasmids directly. These characteristics are independent of whether the DNA insert is flanked by appropriate restriction sites or whether it does, or does not, express a detectable phenotype in yeast. The method is particularly useful for the cloning of large DNA fragments and can be used for plasmids from organisms other than yeasts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 25 (1994), S. 291-298 
    ISSN: 1432-0983
    Schlagwort(e): Cytochrome c 1 ; Cytochrome c 1 heme lyase ; GRF2p ; Glucose repression ; HAPp ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper we examine the expression of the Saccharomyces cerevisiae CYT2 gene, which encodes cytochrome c 1 heme lyase. This enzyme is required for covalent attachment of heme to apocytochrome c 1, a subunit of the mitochondrial respiratory chain. Transcription of the 1-kb CYT2 mRNA initiates at four prominent sites at a distance of 52–225 bp in front of the AUG start codon. The level of CYT2 mRNA is not influenced by the presence or absence of oxygen or of heme, but it is subject to carbonsource control. The concentration of the CYT2 mRNA is significantly reduced in glucose-grown cells as compared to cells grown under non-repressing conditions. Neither the HAPp activator proteins nor MIG1p, a repressor protein involved in glucose repression, seem to mediate this effect.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; recA gene expression ; UV radiation ; Mitotic gene conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of the Escherichia coli RecA protein on mitotic recombination in the diploid D7 strain of Saccharomyces cerevisiae damaged by UV radiation was investigated. The D7 strain was transformed by two modified versions of the pNF2 plasmid: one, containing the ADH-1 promoter, and the other containing the recA gene tandemly arranged behind the ADH-1 promoter region. Immunological analysis proved the presence of the 38-kDa RecA protein in D7/pNF2ADHrecA transformants. We observed a positive effect of recA gene expression on mitotic gene conversion, mainly at higher doses of UV radiation. The results indicate that a RecA-like activity could participate in steps preceeding mitotic conversion events in yeast.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 26 (1994), S. 15-20 
    ISSN: 1432-0983
    Schlagwort(e): Cell-division cycle ; Mitochondrial genome ; Nuclear mutation ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In former studies it was found that the ERV1 gene is essential for cell viability and for the biogenesis of functional mitochondria. A temperature-sensitive nuclear mutant exhibits a severe reduction in all the mitochondrial transcripts. Elimination of the gene leads to growth arrest after a few cell divisions. The putative gene product bears the characteristics of a regulatory factor since it has low expression rate and a high content of charged amino acids. In this study it is further verified that the ERV1 gene alone is responsible for the observed cellular and mitochondrial defects. The 5′ region of the gene is analysed by DNA deletions and complementation studies. Expression of the gene under the control of the GAL1-10 promoter in a disruption strain of ERV1 allows a more detailed specification of its influence on mitochondrial and cellular functions. Immediate and complete loss of mitochondrial genomes is observed after the promoter has been shut off, whereas the yeast cells are still able to grow for a limited time under these conditions. Analysis of the cells by in-vivo DNA flurorescence demonstrates a specific arrest in the cell-division cycle as the terminal phenotype. To further characterize the temperature-sensitive allele of ERV1 the mutated gene has been isolated and sequenced. A single point mutation which leads to the exchange of a single amino acid is found in the reading frame.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Nuclear gene ; Mitochondria ; Mitochondrial ribosomal protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nuclear gene MRP-L13 of Saccharomyces cerevisiae, which codes for the mitochondrial ribosomal protein YmL13, has been cloned and characterized. It is a single-copy gene residing on chromosome XI. Its nucleotide sequence was found to be identical to that of the previously reported ORF YK105. A comparison of the predicted protein sequence of the MRP-L13 gene product and the actual N-terminal amino-acid sequence of the isolated YmL13 protein indicated that the mature protein is preceded by a mitochondrial signal peptide of 86 amino-acid residues, which is the longest among all known mitochondrial ribosomal proteins of S. cerevisiae. No sequence similarity was found to any other ribosomal protein in the current databases. The transcription of MRP-L13 was found to be repressed in the presence of glucose. Its protein product is not strictly essential for mitochondrial functions, but disruption of the gene by insertion of LEU2 noticeably affected cellular growth on non-fermentable carbon sources.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 25 (1994), S. 289-289 
    ISSN: 1432-0983
    Schlagwort(e): Saccharomyces cerevisiae ; Inducible antisense gene ; Acetolactate synthase ; Bradytrophic phenocopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A previous report of the use of antisense RNA to regulate gene expression in yeast is incorrect.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    ISSN: 1432-0983
    Schlagwort(e): Psoralen sensitivity ; Saccharomyces cerevisiae ; DNA repair ; Oxidative stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The complementation and genetical analysis of yeast mutants sensitive to photoactivated 3-carbethoxy-psoralen define three novel recessive mutant alleles pso-5-1, pso6-1, and pso7-1. Their cross-sensitivity to UV254nm, radiomimetic mutagens, and to chemicals enhancing oxidative stress suggest that these mutants are either impaired in metabolic steps protecting from oxidative stress or in mechanisms of the repair of oxygen-dependent DNA lesions. None of the three novel mutant alleles block the induction of reverse mutation by photoactivated mono- and bi-functional psoralens, nitrogen mustards, or UV254nm.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    ISSN: 1432-0983
    Schlagwort(e): tRNA processing ; Saccharomyces cerevisiae ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We used a genetic approach to study the nuclear factors involved in the biogenesis of mitochondrial tRNAs. A point mutation in the mitochondrial tRNAAsp gene of Saccharomyces cerevisiae had previously been shown to result in a temperature-sensitive respiratory-deficient phenotype as a result of the absence of 3′ end-processing of the tRNAAsp. Analysis of mitochondrial revertants has shown that all revertants sequenced have a G-A compensatory change at position 53, which restores the hydrogen-bond with the mutated nucleotide. We then searched for nuclear suppressors to identify the nuclear gene(s) involved in mitochondrial tRNA 3′ end-processing. One such suppressor mutation was further characterized: it restores tRNAAsp maturation and growth at 36°C on glycerol medium in heterozygous diploids, but leads to a defective growth phenotype in haploids.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    ISSN: 1432-0983
    Schlagwort(e): Overexpression ; Peroxisomes ; Saccharomyces cerevisiae ; Stabilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have constructed a gene coding for the 12-kDa intermediate form of the 2s methionine-rich protein from Bertholletia excelsa seeds. This protein, expressed intracellularly in yeast, is characterised by a 20-min balf-life. By adding 11 amino acids corresponding to the peroxisome-targeting sequence (PTSc) of luciferase, we have significantly increased its half-life. This stabilization allowed accumulation of the BZN protein into the peroxisome as judged by cell fractionation. Accumulation of the 12-kDa protein results in a significant increase of the total methionine content in yeast cells (30%) indicating that such a microorganism could represent a practicable protected shuttl for an animal-feed additive.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    ISSN: 1432-0983
    Schlagwort(e): Cytochrome oxidase ; Revertant ; Mitochondria ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three respiratory-deficient mutants of cytochrome oxidase subunit I in the yeast mitochondrion have been sequenced. They are located in, or near, transmembrane segment VI, the catalytic core of the enzyme. Respiratory-competent revertants have been selected and studied. The mutant V244M was found to revert at the same site in valine (wild-type), isoleucine or threonine. The revertants of the mutant G251R were of three types: glycine (wild-type), serine and threonine at position 251. A search for second-site mutations was carried out but none were found. Among 60 revertants tested, the mutant K265M was found to revert only to the wild-type allele.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 162 (1994), S. 211-214 
    ISSN: 1432-072X
    Schlagwort(e): Killer toxin ; Saccharomyces cerevisiae ; Toxin binding ; Cell wall receptor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A recently described new method for determination of killer toxin activity was used for kinetic measurenments of K1 toxin binding. The cells of the killer sensitive strain Saccharomyces cerevisiae S6 were shown to carry two classes of toxin binding sites differing widely in their half-saturation constants and maximum binding rates. The low-affinity and high-velocity binding component (K T1=2.6x109 L.U./ml, V max1=0.19 s-1) probably reflects diffusion-limited binding to cell wall receptors; the high-affinity and low-velocity component (K T2=3.2x107 L.U./ml, V max2=0.03 s-1) presumably indicates the binding of the toxin to plasma membrane receptors. Adsorption of most of the killer toxin K1 to the surface of sensitive cells occured within 1 min and was virtually complete within 5 min. The amount of toxin that saturated practically all cell receptors was about 600 lethal units (L.U.) per cell of S. cerevisiae S6.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    ISSN: 1432-072X
    Schlagwort(e): Rylux BSU ; Fluorescent brightener ; Cell walls ; Chitin synthase ; Glucan synthase ; Yeast ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Rylux BSU, a new fluorescent brightener from the family of 4,4′-diaminostilbene-2,2′disulfonic acid derivatives, inhibited growth and cytokinesis of the yeast Saccharomyces cerevisiae. In the presence of 0.1–1 mg/ml Rylux BSU the cells grew in clumps, had irregular shape and were larger than controls. They formed apparently normal primary septa but their secondary septa and lateral cell walls, especially those in older cells, were abnormally thick with large deposits of amorphous wall material in the periplasmic spaces all over the cell surface. Chitin content in the cell walls of cells grown in the presence of Rylux BSU was increased 2 to 5 times in comparison to that of the controls and glucan content was reduced by up to 30%. In the in vitro assays with particulate membrane fractions, Rylux BSU acted as a non-competitive inhibitor of β-1,3-glucan synthase with inhibitory constant K i=1.75 mg/ml whereas the chitin synthase was inhibited to a much lesser extent. From the difference of the effects of Rylux BSU on the synthesis of chitin in vivo and in vitro it is concluded that the brightener interacts with chitin synthase only indirectly, possibly by influencing the properties of integral plasma membrane.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 162 (1994), S. 211-214 
    ISSN: 1432-072X
    Schlagwort(e): Key words     Killer toxin ; Saccharomyces cerevisiae ; Toxin binding ; Cell wall receptor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract      A recently described new method for determination of killer toxin activity was used for kinetic measurements of K1 toxin binding. The cells of the killer sensitive strain Saccharomyces cerevisiae S6 were shown to carry two classes of toxin binding sites differing widely in their half-saturation constants and maximum binding rates. The low-affinity and high-velocity binding component (K T1 = 2.6 × 109 L.U./ml, V max1 = 0.19 s– 1) probably reflects diffusion-limited binding to cell wall receptors; the high-affinity and low-velocity component (K T2 = 3.2 × 107 L.U./ml, V max2 = 0.03 s– 1) presumably indicates the binding of the toxin to plasma membrane receptors. Adsorption of most of the killer toxin K1 to the surface of sensitive cells occured within 1 min and was virtually complete within 5 min. The amount of toxin that saturated practically all cell receptors was about 600 lethal units (L.U.) per cell of S. cerevisiae S6.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 13 (1994), S. 30-34 
    ISSN: 1476-5535
    Schlagwort(e): Phytate ; Saccharomyces cerevisiae ; Polyacrylamide gel ; Inositol phosphates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Saccharomyces cerevisiae in the form of baker's yeast, cells cultivated on a yeast extract-peptone-glucose medium, as well as cells immobilized in 18% (w/v) polyacrylamide gel showed the ability to hydrolyze 1.727 mM sodium phytate solution at 45°C, pH 4.6, in a stirred tank reactor. Seventy percent yield of dephosphorylation was observed after 2 h using a baker's yeast concentration of 5.8 g dry matter per 100 ml. Hydrolytic activity at 1.8–2.0 μM Pi min−1 was observed between 1st and 3rd h of the reaction in cells cultured 24 or 48 h. No inhibition by the substrate was found at sodium phytate concentrations of 0.587–1.727 mM. After 1.5 h of hydrolysis a single, well distinguished peak ofmyo-inositol-triphosphate was the main product found. By means of immobilization the stability of the biocatalyst was enhanced 3.3-fold and reached its half-life at 64 ninety-minute runs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 13 (1994), S. 269-272 
    ISSN: 1476-5535
    Schlagwort(e): Wine ; Yeasts ; Fatty acids ; Ethyl esters ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary The evolution of the cell and must contents of three short-chain fatty acids (C6, C8 and C10) and their ethyl esters during fermentations withSaccharomyces cerevisiae racescerevisiae, bayanus andcapensis were studied. The former is a fermentative yeast and the last two are ‘flor’ film yeasts. The acid concentrations in the musts increased throughout the alcoholic fermentations, and maximum cell concentrations of the fatty acids were reached after 48 h of fermentation. Maximum ester concentrations in the cells were attained after 48–72 h of fermentation. In the musts, ethyl octanoate and ethyl decanoate reached a peak also at this point, and ethyl hexanoate after 10 days. After 134 days,S. cerevisiae racecapensis formed a thick ‘flor’ film whileS. cerevisiae racebayanus developed a thin film andS. cerevisiae racecerevisiae formed no film. At this point, acid contents remained constant in the wines produced byS. cerevisiae racescerevisiae andbayanus, and decreased in those obtained with racecapensis. The ethyl ester contents tended to decrease with the exception of ethyl decanoate in the fermentations carried out byS. cerevisiae racescerevisiae andbayanus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Ecological research 9 (1994), S. 357-360 
    ISSN: 1440-1703
    Schlagwort(e): balloon system ; Coleoptera ; pollinators ; tree canopy ; wood borers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A system of suspending traps from a movable balloon was developed and tested on pollinating and wood boring Coleoptera in a tropical rainforest canopy in Pasoh Forest Reserve, Peninsular Malaysia. The balloons, 2.5 m in diameter, were filled with helium gas for levitation and moored in different directions by three pieces of thin rope. Traps in which benzyl acetate and ethanol were used as attractants for the pollinators and wood borers, respectively, were suspended from the balloon at different heights. The trapping results show that the balloon system can be used for studying canopy insects and their vertical distribution on a spatial and temporal scale.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 2673-2685 
    ISSN: 1573-1561
    Schlagwort(e): Maladera matrida ; Coleoptera ; Scarabaeidae ; collection of volatiles ; field trapping ; olfactometer ; attractants ; host plant volatiles ; synergism ; aggregation ; sex pheromone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract TheMaladera matrida beetle (Coleoptera, Scarabaeidae, Melolonthinae), a relatively new species to science, was first identified in Israel in 1983. In the course of field observations it was found that adultM. matrida beetles emerged from the soil at sunset to feed and mate. During the first 20 min of flight, most of the beetles were males. The females emerged shortly afterwards, and aggregations numbering 20–30 individuals with equal proportions of males and females were eventually formed on peanut plants. Laboratory olfactometer bioassays showed that peanut leaves (food) attracted both males and females. Field-trapping experiments and olfactometer studies showed thatM. matrida beetles were highly attracted by live virgin females in the presence of food (cut-up peanut leaves). Another set of field trapping experiments indicated that airborne volatiles produced by live virgin females plus food had the same attracting ability as live virgin females plus food. The attraction exerted by the combination of live virgin females and peanut leave volatiles suggests a synergism effect. Accordingly, we propose a two-stage mechanism of chemical communication in theM. matrida beetles: first, the males cause mechanical damage to the host plant to attract both sexes; later, the females emit attractants (sex pheromone) while eating or shortly thereafter.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 361-371 
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scarabaeidae ; Maladera matrida ; aggregation ; plant volatiles ; olfactometer ; attractant ; behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract AdultMaladera matrida Argaman (Coleoptera: Scarabaeidae: Melolonthinae) males emerge from soil for an active period at dusk, a few minutes before the females. Adults are found during most of the active hours on the foliage in aggregations composed of an equal sex ratio. The mechanism of aggregation behavior ofM. matrida beetles was studied in a Y-shaped olfactometer. No evidence was found for the existence of an aggregation pheromone released either by males or by females, but behavior tests indicate that adultM. matrida beetles, males as well as females, are attracted to volatiles of an injured host plant. The following scenario is suggested: Males emerge daily from soil at dusk, a few minutes before the females, and immediately start feeding. Additional males are attracted to the injured host's volatiles and form aggregations. When females emerge from soil, the attractant volatiles are concentrated in spots, and the females join the aggregations, forming an equal sex ratio.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 753-769 
    ISSN: 1573-1561
    Schlagwort(e): Contact chemoreception ; electrophysiology ; taste ; leaf alcohols ; galeal sensilla ; feeding behavior ; host selection ; gustatory coding ; Colorado potato beetle ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Larvae and adults of the Colorado potato beetle,Leptinotarsa decemlineata (Say), are shown to have galeal gustatory cells that are highly sensitive to distillate of potato leaf extracts, (E)-2-hexen-1-ol, (E)-2-hexenal, and other saturated and unsaturated six-carbon alcohols. In larvae and adults, the sensory response patterns elicited by leaf homogenate, leaf distillate and a mixture of these two extracts differ in subtle ways. Beetle larvae feed most readily on Millipore disks treated with leaf homogenate and the mixture, but they did not feed on disks treated with leaf distillate. The differences in behavioral response and sensory input are used to derive a potential gustatory code that may stimulate different levels of feeding. This code may be disrupted by compounds present in nonhost leaves, thus leading to reduced feeding. Possible interactions of sapid leaf volatiles, amino acids, sugars, and potentially deterrent plant compounds are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 1429-1444 
    ISSN: 1573-1561
    Schlagwort(e): Tomicus piniperda ; Thanasimus formicarius ; Rhizophagus depressus ; Rhizophagus ferrugineus ; Epuraea spp. ; Acanthocinus aedilis ; predators ; competitors ; attractants ; α-pinene ; ethanol ; Scolytidae ; Cleridae ; Rhizophagidae ; Cerambycidae ; Coleoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Bolts of Scots pine,Pinus sylvestris L., attacked by the bark beetleTomicus piniperda (L.) were baited with ethanol and α-pinene to attract antagonistic insects and thereby enhance their detrimental effects on the production of bark beetle progeny. Unbaited and caged bolts were included in the experiments as controls. Attraction of beetles to the bolts and subsequent emergence were estimated using traps. Six phloem-feeding species (potential competitors ofT. piniperda) and four predatory species were caught in significantly higher numbers at the baited bolts than at the unbaited ones. The number of offspring and the productivity ofT. piniperda were four to seven times higher in unbaited bolts than in baited bolts. Exclusion of other insects, by using cages, resulted in a nine-fold increase in the number ofT. piniperda offspring per square meter and productivity (offspring per egg gallery) compared with unbaited, exposed bolts.Hylurgops palliatus (Gyll.) (Scolytidae) andRhagium inquisitor (L.) (Cerambycidae) attacked both the baited and unbaited bolts, whereasAcanthocinus aedilis (L.) (Cerambycidae) andPytho depressus (L.) (Pythidae) reproduced almost exclusively in the baited ones. Large numbers of larvae ofThanasimus (Cleridae) andRhizophagus (Rhizophagidae) emerged from both the baited and unbaited bolts. Adults ofPlegaderus vulneratus (Panzer) andCylister linearis (Er.) (Histeridae) emerged almost exclusively from the baited bolts. The low progeny production ofT. piniperda in the baited bolts was attributed largely to the influence of adults ofRhizophagus andEpuraea (Nitidulidae), and larvae ofThanasimus andA. aedilis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 1483-1493 
    ISSN: 1573-1561
    Schlagwort(e): Carpophilus obsoletus ; sap beetle ; Coleoptera ; Nitidulidae ; aggregation pheromone ; hydrocarbon ; tetraene ; date
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Males ofCarpophilus obsoletus Erichson produce an aggregation pheromone to which both sexes respond. The pheromone was identified by GC-MS as (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-undecatetraene (1), which is also a minor constituent of the pheromone blends ofC. hemipterus (L.),C. freemani Dobson, andC. lugubris Murray. The pheromone was synergized in wind-tunnel bioassays by propyl acetate, a “host-type” coattractant. In a dose-response study, 50 pg of1, plus propyl acetate, was significantly more attractive than just propyl acetate. Pheromone emission from groups of 65 males, feeding on artificial diet, averaged 2.2 ng/male/day. Emissions from individual males were larger, averaging 72 ng/day and ranging as high as 388 ng/day. Synthetic1 was tested in a date garden in southern California (500 µg/rubber septum), using fermenting whole-wheat bread dough as the coattractant. The pheromone plus dough attracted significantly more beetles than dough alone (means were 4.2 and 0.0 beetles per week per trap). Captured beetles were 54% females. Field trap catches were highest during the months of July and August.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    ISSN: 1573-1561
    Schlagwort(e): Anomala orientalis ; Oriental beetle ; Coleoptera ; Scarabaeidae ; sex pheromone ; (Z)- and (E)-7-tetradecen-2-one ; DMDS derivatization ; flight tunnel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Females of the Oriental beetle,Anomala orientalis (Waterhouse), release a sex pheromone composed of a 9:1 blend of (Z)- and (E)-7-tetradecen-2-one. The double-bond position of the pheromone was determined by DMDS derivatization and interpretation of the fragmentation patterns produced by monounsaturated ketones. In a sustained-flight tunnel, males responded by flying toward female beetles and attempting to copulate with them. Both effluvium and whole-body extracts of OB females were analyzed, and the activity was found only in the airborne extracts. Flight-tunnel bioassays also showed that a synthetic 90:10Z/E blend on a rubber septum was attractive and that the responses of males to this blend were equivalent toZ isomer alone, but much better than to the singleE isomer.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Molecular biology reports 20 (1994), S. 135-141 
    ISSN: 1573-4978
    Schlagwort(e): mitochondria ; multienzyme complex ; replication ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A 40 S multienzyme complex containing mtDNA polymerase was isolated from mitochondria ofS. cerevisiae by density gradient centrifugation and by gel filtration chromatography. Besides DNA polymerase, RNA polymerase, primase, 3′→5′ exonuclease and an ATPase activities were found to be associated with it. The presence of some of these enzymes were confirmed by Western blot. This high molecular weight multienzyme complex containing DNA has most of the attributes of a putative replisome.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    ISSN: 1573-5028
    Schlagwort(e): Arabidopsis thaliana ; cDNA ; complementation ; erg20-2 yeast mutant ; farnesyl diphosphate synthase ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A cDNA encoding farnesyl diphosphate synthase, an enzyme that synthesizes C15 isoprenoid diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate, was cloned from an Arabidopsis thaliana cDNA library by complementation of a mutant of Saccharomyces cerevisiae deficient in this enzyme. The A. thaliana cDNA was also able to complement the lethal phenotype of the erg20 deletion yeast mutant. As deduced from the full-length 1.22 kb cDNA nucleotide sequence, the polypeptide contains 343 amino acids and has a relative molecular mass of 39689. The predicted amino acid sequence presents about 50% identity with the yeast, rat and human FPP synthases. Southern blot analyses indicate that A. thaliana probably contains a single gene for farnesyl diphosphate synthase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    ISSN: 1617-4623
    Schlagwort(e): Cerulenin ; Saccharomyces cerevisiae ; Fatty acid synthase ; β-Ketoacyl synthase ; Drug resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cerulenin, an antifungal antibiotic produced by Cephalosporium caerulens, is a potent inhibitor of fatty acid synthase in various organisms, including Saccharomyces cerevisiae. The antibiotic inhibits the enzyme by binding covalently to the active center cysteine of the condensing enzyme domain. We isolated 12 cerulenin-resistant mutants of S. cerevisiae following treatment with ethyl methanesulfonate. The mechanism of cerulenin resistance in one of the mutants, KNCR-1, was studied. Growth of the mutant was over 20 times more resistant to cerulenin than that of the wild-type strain. Tetrad analysis suggested that all mutants mapped at the same locus, FAS2, the gene encoding the α subunit of the fatty acid synthase. The isolated fatty acid synthase, purified from the mutant KNCR-1, was highly resistant to cerulenin. The cerulenin concentration causing 50% inhibition (IC50) of the enzyme activity was measured to be 400 μM, whereas the IC50 value was 15 μM for the enzyme isolated from the wild-type strain, indicating a 30-fold increase in resistance to cerulenin. The FAS2 gene was cloned from the mutant. Sequence replacement experiments suggested that an 0.8 kb EcoRV-HindIII fragment closely correlated with cerulenin resistance. Sequence analysis of this region revealed that the GGT codon encoding Gly-1257 of the FAS2 gene was altered to AGT in the mutant, resulting in the codon for Ser. Furthermore, a recombinant FAS2 gene, in which the 0.8 Kb EcoRV-HindIII fragment of the wild-type FAS2 gene was replaced with the same region from the mutant, when introduced into FAS2-defective S. cerevisiae complemented the FAS2 pheno-type and showed cerulenin resistance. These data indicate that one amino acid substitution (Gly → Ser) in the α subunit of fatty acid synthase is responsible for the cerulenin resistance of the mutant KNCR-1.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Transcriptional regulation ; Chromatin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract GAL11 was first identified as a gene required for full expression of some galactose-inducible genes that are activated by GAL4, and it was subsequently shown to be necessary for full expression of another set of genes activated by RAP1/GRFl/TUF. Genetic analysis suggests that GAL11 functions as a coactivator, mediating the interaction of sequence-specific activators with basal transcription factors. To test this hypothesis, we first tried to identify functional domains by deletion analysis and found that the 866–910 region is indispensable for function. Using reporters bearing various upstream activating sequences (UAS) and different core promoter structures, we show that the involvement of GAL11 in transcriptional activation varies with the target promoter and the particular combination of cis elements. Gel electrophoresis in the presence of chloroquine shows that GAL11 affects the chromatin structure of a circular plasmid. Based on these findings, the role of GAL 11 in regulation of transcription, including an alteration in chromatin structure, is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 244 (1994), S. 260-268 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Amino acid permeases ; Transport ; Tryptophan
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract SCM2, a novel gene encoding a yeast tryptophan permease, was cloned as a high-copy-number suppressor of cse2-1. The cse2-1 mutation causes cold sensitivity, temperature sensitivity and chromosome missegregation. However, only the cold-sensitive phenotype of cse2-1 cells is suppressed by SCM2 at high copy. SCM2 is located on the left arm of yeast chromosome XV, adjacent to SUP3 and encodes a 65 kDa protein that is highly homologous to known amino acid permeases. Four out of five disrupted scm2 alleles (scm2Δ1-Δ4) cause slow growth, whereas one disrupted allele (scm2Δ5) is lethal. Cells with both the scm2Δ1 and trp1-Δ101 mutations exhibit a synthetic cold-sensitive phenotype and grow much more slowly at the permissive temperature than cells with a single scm2Δ1 or trp1-Δ101 mutation. A region of the predicted SCM2 protein is identical to the partial sequence recently reported for the yeast tryptophan permease TAP2, indicating that SCM2 and TAP2 probably encode the same protein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    ISSN: 1617-4623
    Schlagwort(e): Drug sensitivity ; Saccharomyces cerevisiae ; Major facilitator superfamily ; Drug expulsion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several pleiotropic drug sensitivities have been described in yeast. Some involve the loss of putative drug efflux pumps analogous to mammalian P-glycoproteins, others are caused by defects in sterol synthesis resulting in higher plasma membrane permeability. We have constructed a Saccharomyces cerevisiae strain that exhibits a strong crystal violet-sensitive phenotype. By selecting cells of the supersensitive strain for normal sensitivity after transformation with a wild-type yeast genomic library, a complementing 10-kb DNA fragment was isolated, a 3.4-kb subfragment of which was sufficient for complementation. DNA sequence analysis revealed that the complementing fragment comprised the recently sequenced SGE1 gene, a partial multicopy suppressor of gal11 mutations. The supersensitive strain was found to be a sge1 null mutant. Overexpression of SGE1 on a high-copy-number plasmid increased the resistance of the supersensitive strain. Disruption of SGE1 in a wild-type strain increased the sensitivity of the strain. These features of the SGE1 phenotype, as well as sequence homologies of SGE1 at the amino acid level, confirm that the Sge1 protein is a member of the drug-resistance protein family within the major facilitator superfamily (MFS).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Transcription factor ; Zinc finger ; Multidrug resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract TheSaccharomyces cerevisiae PDR3 gene, located near the centromere of chromosome II, has been completely sequenced and characterised. Mutationspdr3-1 andpdr3-2, which confer resistance to several antibiotics can be complemented by a wild-type allele of the PDR3 gene. The sequence of the wild-typePDR3 gene revealed the presence of a long open reading frame capable of encoding a 976-amino acid protein. The protein contains a single Zn(II)2Cys6 binuclear-type zinc finger homologous to the DNA-binding motifs of other transcriptional activators from lower eukaryotes. Evidence that the PDR3 protein is a transcriptional activator was provided by demonstrating that DNA-bound LexA-PDR3 fusion proteins stimulate expression of a nearby promoter containing LexA binding sites. The use of LexA-PDR3 fusions revealed that the protein contains two activation domains, one localised near the N-terminal, cysteine-rich domain and the other localised at the C-terminus. The salient feature of the PDR3 protein is its similarity to the protein coded byPDR1, a gene responsible forpleiotropicdrugresistance. The two proteins show 36% amino acid identity over their entire length and their zinc finger DNA-binding domains are highly conserved. The fact that the absence of both PDR1 and PDR3 (simultaneous disruption of the two genes) enhances multidrug sensitivity strongly suggests that the two transcriptional factors have closely related functions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    ISSN: 1617-4623
    Schlagwort(e): Nuclear suppressor gene ; Mitochondrial functions ; Glucose repression ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We previously isolated a nuclear 5.7 kb genomic fragment carrying the NAM7/UPF1 gene, which is able to suppress mitochondrial splicing deficiency when present in multiple copies. We show here that an immediately adjacent gene ISF1 (Increasing Suppression Factor) increases the efficiency of the NAM7/UPF1 suppressor activity. The ISF1 gene has been independently isolated as the MBR3 gene and comparison of the ISF1 predicted protein sequence with data libraries revealed a significant similarity with the MBRI yeast protein. The ISF1 and NAM7 genes are transcribed in the same direction, and RNase mapping allowed the precise location of their termini within the intergenic region to be determined. The ISF1 gene is not essential for cell viability or respiratory growth. However as for many mitochondrial genes, ISF1 expression is sensitive to fermentative repression; in contrast expression of the NAM7 gene is unaffected by glucose. We propose that ISF1 could influence the NAM7/UPF1 function, possibly at the level of mRNA turnover, thus modulating the expression of nuclear genes involved in mitochondrial biogenesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Mitochondria ; Cytochrome b ; Complex II ; HAP2/3/4
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Computer-assisted structural analysis of the predicted product of the previously described open reading frame (ORF) YKL4 located on the left arm of chromosome XI of Saccharomyces cerevisiae revealed a high degree of similarity (〉50%) to bovine cytochrome b 560, the sdhC polypeptide of the Escherichia coli succinate dehydrogenase (SDH) complex and the protein specified by ORF137 located on the chloroplast DNA of Marchantia polymorpha. Disruption of the yeast gene severely impaired mitochondrial function, while Northern analysis showed it to be subject to catabolite repression. Deletion analysis of the CYB3 promoter identified a single HAP2/3/4-binding element that is necessary and sufficient for carbon source-dependent transcriptional regulation. These experiments also suggested the presence of additional, as yet unidentified, transcriptional control elements, both negative and positive. Taken together, these data lead us to conclude that the CYB3 gene encodes the yeast homolog of the bovine cytochrome b 560 component of complex II of the mitochondrial electron transport chain.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; CYP1(HAP1) protein ; Electron transport ; Oxygen and heme regulation ; Trans regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract CYP1 determines the expression of several genes whose transcription is heme-dependent in yeast. It exerts regulatory functions even in the absence of heme, usually considered to be its effector. It mediates both positive and negative effects, depending on the target gene and on the redox state of the cell. In the presence of heme, it binds through a cysteine-rich domain in which a histidine residue occupies the position of the sixth and essential cysteine of the otherwise classical zinc cluster DNA-binding domain exemplified by GAL4. We constructed specific missense mutations in the potential CYP1 zinc cluster domain by site-directed mutagenesis and looked for regulatory effects of the mutated proteins under specific physiological conditions. We show that CYP1 does belong to the zinc cluster regulatory family since a sixth essential cysteine residue is indeed present, albeit at a modified position when compared to the consensus sequence. We also show that the amino acid preceding the first cysteine residue of the DNA-binding domain critically affects the efficiency of regulation both in the presence and in the absence of heme: mutations known to affect DNA binding under heme-sufficient conditions also affect regulation under heme-deficient conditions. We therefore surmise that regulation under hemedeficient conditions is dependent upon DNA binding.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    ISSN: 1617-4623
    Schlagwort(e): Multicopy suppressors ; HAP2/3/4 activation complex ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two new yeast genes, named MBR1 and MBR3, were isolated as multicopy suppressors of the growth defect of a strain lacking the HAP2 transcriptional activator. Both genes when overexpressed can also suppress the growth defect of hap3 and hap4 null mutants. However, overexpression of MBRI cannot substitute for the HAP2/3/4 complex in activation of the CYC1 gene. Nucleotide sequencing of MBR1 and MBR3 revealed that these two genes encode serine-rich, hydrophilic proteins with regions of significant homology. The functional importance of one of these conserved regions was shown by mutagenesis. Disruption of MBR1 leads to a partial growth defect on glycerol medium. Disruption of MBR3 has no major effect but the double disruptant shows a synthetic phenotype suggesting that the MBR1 and MBR3 gene products participate in common function.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Meiosis Sporulation ; Divergent promoter ; Developmental regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Promoters that control gene expression in Saccharomyces cerevisiae only in a sporulation-specific manner have previously been isolated from a genomic yeast DNA library fused to a promoterless Escherichia coli lacZ gene. Two novel sporulation-specific genes, SPS18 and SPS19, were isolated using this technique. These genes are divergently controlled by the same promoter but with SPS18 expressed at four times the level of SPS19. Deletion analysis has shown that the promoter elements that exert sporulation control on each of the genes overlap, having a common 25 bp sequence located within the intergenic region. SPS18 encodes a 34-KDa protein of 300 amino acids that contains a putative zinc-binding domain and a region of highly basic residues that could target the protein to the nucleus. SPS19 encodes a 31-KDa protein of 295 amino acids, which has a peroxisomal targeting signal (SKL) at its C terminus; this protein belongs to the family of non-metallo short-chain alcohol dehydrogenases. A null mutation deleting the intergenic promoter prevented expression of both genes, and when homozygous in diploids, reduced the extent of sporulation four-fold; the spores that did form were viable, but failed to become resistant to ether, and were more sensitive to lytic enzymes. This phenotype reflects a defect in spore wall maturation, indicating that the product of at least one of the genes functions during the process of spore wall formation. Therefore these genes belong to the class of late sporulation-specific genes that are sequentially activated during the process of meiosis and spore formation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Duplicate genes ; Synthetic lethal mutants ; CTP synthetase ; Pyrimidine biosynthetic pathway
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the pyrimidine biosynthetic pathway, CTP synthetase catalyses the conversion of uridine 5′-triphosphate (UTP) to cytidine 5′-triphosphate (CTP). In the yeast Saccharomyces cerevisiae, the URA7 gene encoding this enzyme was previously shown to be nonessential for cell viability. The present paper describes the selection of synthetic lethal mutants in the CTP biosynthetic pathway that led us to clone a second gene, named URA8, which also encodes a CTP synthetase. Comparison of the predicted amino acid sequences of the products of URA7 and URA8 shows 78% identity. Deletion of the URA8 gene is viable in a haploid strain but simultaneous presence of null alleles both URA7 and URA8 is lethal. Based on the codon bias values for the two genes and the intracellular concentrations of CTP in strains deleted for one of the two genes, relative to the wild-type level, URA7 appears to be the major gene for CTP biosynthesis. Nevertheless, URA8 alone also allows yeast growth, at least under standard laboratory conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 242 (1994), S. 517-527 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; HSP82 ; Random in vitro mutagenesis ; Temperature-sensitive mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The budding yeast Saccharomyces cerevisiae has two HSP90-related genes per haploid genome, HSP82 and HSC82. Random mutations were induced in vitro in the HSP82 gene by treatment of the plasmid with hydroxylamine. Four temperature-sensitive (ts) mutants and one simultaneously is and cold-sensitivie (cs) mutant were then selected in a yeast strain in which HSC82 had previously been disrupted. The mutants were found to have single base changes in the coding region, which caused single amino acid substitutions in the HSP82 protein. All of these mutations occurred in amino acid residues that are well conserved among HSP90-related proteins of various species from Escherichia coli to human. Various properties including cell morphology, macromolecular syntheses and thermosensitivity were examined in each mutant at both the permissive and nonpermissive temperatures. The mutations in HSP82 caused pleiotropic effects on these properties although the phenotypes exhibited at the nonpermissive temperature varied among the mutants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Cell wall ; Protein kinase C ; β-Glucanase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To obtain more information about the cell wall organization of Saccharomyces cerevisiae, we have developed a novel screening system to obtain cell wall-defective mutants, using a density gradient centrifugation method. Nine hypo-osmolarity-sensitive mutants were classified into two complementation groups, hpo1 and hpo2. Phase contrast microscopic observation showed that mutant cells bearing lesions at either locus became abnormally large. A gene that complemented the mutant phenotype of hpo2 was cloned and sequenced. This gene turned out to be identical to PKC1, which encodes the yeast homologue of mammalian protein kinase C. Complementation tests with pkc1Δ showed that hpo2 is allelic to pkc1. To study the reason for the fragility of hpo2 cells, cell wall was isolated and the glucan was analyzed. The amount of alkali, acid-insoluble glucan, which is responsible for the rigidity of the cell wall, was reduced to about 30% that of the wild-type cell and this may be the major cause of the fragility of the hpo2 mutant cell. Analysis of total wall proteins in hpo2 mutant cells on SDS-polyacrylamide gels revealed that a 33 kDa protein was overproduced two- to threefold relative to the wild-type level. This 33 kDa protein was identified as a β-glucanase, encoded by BGL2. Disruption of BGL2 in the hpo2 mutant partially rescued the growth rate defect. This suggests that the PKC1 kinase cascade regulates BGL2 expression negatively and overproduction of the β-glucanase is partially responsible for the growth defect. Since the bgl2 disruption did not rescue the hypo-osmolarty-sensitive phenotype of the hpo2 mutant, PKC1 must negatively regulate other enzymes involved in the biosynthesis and metabolism of the cell wall.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 358-362 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Oxidative stress ; High temperature viability ; Ubiquitin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract UBI4, the polyubiquitin gene of Saccharomyces cerevisiae, is expressed at a low level in vegetative cells, yet induced strongly in response to starvation, cadmium, DNA-damaging agents and heat shock. UBI4 is also expressed at a higher basal level in cells growing by respiration as compared to glucose-repressed cells growing by fermentation. This higher UBI4 expression of respiratory cultures probably helps to counteract the greater oxidative stress of respiratory growth. The effects of inactivating UBI4 on high temperature viability are more marked with respiratory cultures. Also loss of UBI4 leads to a considerably increased rate of killing of respiring cells by hydrogen peroxide, whereas the same gene inactivation has relatively little effect on the peroxide sensitivity of cells in which mitochondrial functions are repressed. This is the first study to reveal that ubiquitin levels in cells can influence their ability to withstand oxidative stress.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 363-368 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Glycolysis ; Phosphoglucose isomerase ; Antisense ; Double-strand coding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Open reading frames longer than 300 bases were observed in the antisense strands of the genes coding for the glycolytic enzymes phosphoglucose isomerase, phosphoglycerate mutase, pyruvate kinase and alcohol dehydrogenase I. The open reading frames on both strands are in codon register. It has been suggested that proteins coded in codon register by complementary DNA strands can bind to each other. Consequently, it was interesting to investigate whether the open reading frames in the antisense strands of glycolytic enzyme genes are functional. We used oligonucleotide-directed mutagenesis of the PGI1 phosphoglucose isomerase gene to introduce pairs of closely spaced base substitutions that resulted in stop codons in one strand and only silent replacements in the other. Introduction of the two stop codons into the PGI1 sense strand caused the same physiological defects as already observed for pgi1 deletion mutants. No detectable effects were caused by the two stop codons in the antisense strand. A deletion that removed a section from − 31 by to + 109 by of the PGI1 gene but left 83 bases of the 3′ region beyond the antisense open reading frame had the same phenotype as a deletion removing both reading frames. A similar pair of deletions of the PYK1 gene and its antisense reading frame showed identical defects. Our own Northern experiments and those reported by other authors using double-stranded probes detected only one transcript for each gene. These observations indicate that the antisense reading frames are not functional. On the other hand, evidence is provided to show that the rather long reading frames in the antisense strands of these glycolytic enzyme genes could arise from the strongly selective codon usage in highly expressed yeast genes, which reduces the frequency of stop codons in the antisense strand.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 193 (1994), S. 173-186 
    ISSN: 1615-6110
    Schlagwort(e): Rhamnaceae ; Frangula ; Diptera ; Coleoptera ; Hymenoptera ; Mecoptera ; Breeding system ; phenology ; pollination biology ; protandry ; reproductive success ; self-incompatibility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Various aspects of the reproductive biology of the perennial hermaphroditeFrangula alnus Mill. were studied in two populations located in the province of Cádiz, southern Spain. Flowering extends from the second week of May to early July. The small, whitegreenish, entomophilous flowers are incompletely protandrous and last 8–10 days, but pollen transfer takes place only on days 1–3. A very weak, pleasant odour along with nectar and pollen attract over 45 insect species, of which 21 are probable pollinators. These are mainlyDiptera but also includeHymenoptera and the unusual (as flower visitors)Mecoptera. Reproduction is exclusively sexual and strictly xenogamous, with pollen transfer depending solely on insect vectors. Although flower morphology and individual flower phenology do not fully prevent self-pollination, and geitonogamy can easily take place, the level of autogamy was negligible. Therefore, some self-incompatibility mechanism is operative in this species. Only 2.8% of open-pollinated flowers set fruit. At the flower level, fruit initiation was apparently limited by availability of cross-pollen, which in turn seemed influenced by the structure of the population. The seed/ovule ratio in ripe fruits was ca. 50%. Predispersal (maternal) reproductive success (percent ovules becoming filled seeds) was 1.42%. For mature individuals this corresponded to ca. 430 to 1560 potential offspring per year.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    ISSN: 1617-4623
    Schlagwort(e): Bacterio-opsin ; Expression ; Yeast ; Saccharomyces cerevisiae ; Membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The bop gene codes for the membrane protein bacterio-opsin (BO), which on binding all-trans-retinal, constitutes the light-driven proton pump bacteriorhodopsin (BR) in the archaebacterium Halobacterium salinarium The designation H. salinarium instead of the former designation H. halobium is used throughout this paper following the classification of Tindall (1992) . This gene was cloned in a yeast multi-copy vector and expressed in Saccharomyces cerevisiae under the control of the constitutive ADH1 promoter. Both the authentic gene and a modified form lacking the precursor sequence were expressed in yeast. Both proteins are incorporated into the membrane in S. cerevisiae. The presequence is thus not required for membrane targeting and insertion of the archaebacterial protein in budding yeast, or in the fission yeast Schizosaccharomyces pombe, as has been shown previously. However, in contrast to S. pombe transformants, which take on a reddish colour when all-trans-retinal is added to the culture medium as a result of the in vivo regeneration of the pigment, S. cerevisiae cells expressing BO do not take on a red colour. The precursor of BO is processed to a protein identical in size to the mature BO found in the purple membrane of Halobacterium. The efficiency of processing in S. cerevisiae is dependent on growth phase, as well as on the composition of the medium and on the strain used. The efficiency of processing of BR is reduced in S. pombe and in a retinal-deficient strain of H. salinarium, when retinal is present in the medium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    ISSN: 1617-4623
    Schlagwort(e): Arabidopsis thaliana ; Saccharomyces cerevisiae ; Complementation ; Aspartate transcarbamylase ; Orotate phosphoribosyl transferase ; Orotidine-5′-phosphate decarboxylase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An Arabidopsis thaliana cDNA library was used to complement Saccharomyces cerevisiae pyrimidine auxotrophic mutants. Mutants in all but one (carbamylphosphate synthetase) of the six steps in the de novo pyrimidine biosynthetic pathway could be complemented. We report here the cloning, sequencing and computer analysis of two cDNAs encoding the aspartate transcarbamylase (ATCase; EC 2.1.3.2) and orotate phosphoribosyltransferase-orotidine-5′-phosphate decarboxylase (OPRTase-OMP-decase; EC 2.4.2.10, EC 4.1.1.23) enzymes. These results confirm the presence in A. thaliana of a bifunctional gene whose product catalyses the last two steps of the pyrimidine biosynthetic pathway, as previously suggested by biochemical studies. The ATCase encoding cDNA sequence (PYRB gene) shows an open reading frame (ORF) of 1173 by coding for 390 amino acids. The cDNA encoding OPRTase-OMPdecase (PYRE-F gene) shows an ORF of 1431 by coding for 476 amino acids. Computer analysis of the deduced amino acid sequences of both cDNAs shows the expected high similarity with the ATCase, ornithine transcarbamylase (OTCase; EC 2.1.3.3), OPRTase and OMPdecase families. This heterospecific cloning approach increases our understanding of the genetic organization and interspecific functional conservation of the pyrimidine biosynthetic pathway and underlines its usefulness as a model for evolutionary studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    ISSN: 1617-4623
    Schlagwort(e): HAP3 ; Saccharomyces cerevisiae ; Kluyveromyces lactis ; Zinc finger ; Carbon source regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Kluyveromyces lactis homologue of the Saccharomyces cerevisiae HAP3 gene was isolated by functional complementation of the respiratory-deficient phenotype of the S. cerevisiae hap3::HIS4 strain SHY40. The KlHAP3 gene encodes a protein of 205 amino acids, of which the central B-domain of 90 residues is highly homologous to HAP3 counterparts of S. cerevisiae and higher eukaryotes. The protein contains a novel 4-cysteine zinc-finger motif and we propose by analogy that all other homologous HAP3 proteins contain the same motif, with the position containing the third cysteine being occupied by a serine residue. In contrast to the situation in S. cerevisiae, disruption of the KlHAP3 gene in K. lactis does not result in a respiratory-deficient phenotype and the growth of the null strain is indistinguishable from wild type. There is also no effect on the expression of the carbon source-regulated KlCYC1 gene, suggesting either a different role for the HAP2/3/4 complex, or the existence of a different mechanism of carbon source regulation. Sequence verification of the S. cerevisiae HAP3 locus reveals that, just as in K. lactis, a long open reading frame (ORF) is present upstream of the HAP3 gene. These highly homologous ORFs are predicted to have at least eight membrane-spanning fragments, but do not show significant homology to any known sequence present in databases. The ScORFX gene is transcribed in the opposite direction to ScHAP3, but, in contrast to an earlier report by Hahn et al. (1988), the transcripts of the two genes do not overlap. The model proposed by these authors, in which the ScHAP3 gene is regulated by an anti-sense non-coding mRNA, is therefore not correct.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 245 (1994), S. 686-693 
    ISSN: 1617-4623
    Schlagwort(e): Yeast ; Saccharomyces cerevisiae ; Poly(ADP-ribose) polymerase ; DNA repair
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The coding sequence for human poly(ADP-ribose) polymerase was expressed inducibly in Saccharomyces cerevisiae from a low-copy-number plasmid vector. Cell free extracts of induced cells had poly(ADPribose) polymerase activity when assayed under standard conditions; activity could not be detected in non-induced cell extracts. Induced cells formed poly(ADP-ribose) in vivo, and levels of these polymers increased when cells were treated with the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). The cytotoxicity of this agent was increased in induced cells, and in vivo labelling with [3H]adenine further decreased their viability. Increased levels of poly(ADP-ribose) found in cells treated with the alkylating agent were not accompanied by lowering of the NAD concentration.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; ts mutant ; Recovery ; HTR1 ; MCS1/SSD1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new temperature-sensitive mutant of Saccharomyces cerevisiae was isolated. Arrested cells grown at the nonpermissive temperature were of dumb-bell shape and contained large vacuoles. A DNA fragment was cloned based on its ability to complement this temperature sensitivity. The HTR1 gene encodes a putative protein of 93 kDa without significant homology to any known proteins. The gene was mapped between ade5 and lys5 on the left arm of chromosome VII. The phenotype of the gene disruptant appeared to be strain-specific; disruption of the gene in strain W303 caused the cells to become temperature sensitive. The arrested phenotype here was similar to that of the original is mutant and cells in G2/M phase predominated at high temperature. Another disruptant in a strain YPH background grew slowly at high temperature due to slow progression through G2/M phase, and morphologically abnormal (elongated) cells accumulated. A single-copy suppressor that alleviated the temperature-sensitive defects in both strains was identified as MCS1/SSD1. The wild-type strains W303 and YPH are known to carry defective MCS1/SSD1 alleles; hence HTR1 may function redundantly with MCS1/SSD1 to suppress the temperature-sensitive phenotypes. In addition, based on a halo bioassay, the disruptant strains appeared to be defective in recovery from, or adaptive response to G1 arrest mediated by mating pheromone, even at the permissive temperature. Thus the gene has at least two functions and is designated HTR1 (required for high temperature growth and recovery from G1 arrest induced by mating pheromone).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Cell cycle ; Bud site selection ; Guanine exchange factor ; Ras
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Guanine Exchange Factor (GEF) activity for Ras proteins has been associated with a conserved domain in Cdc25p, Sdc25p in Saccharomyces cerevisiae and several other proteins recently found in other eukaryotes. We have assessed the structure-function relationships between three different members of this family in S. cerevisiae, Cdc25p, Sdc25p and Bud5p. Cdc25p controls the Ras pathway, whereas Bud5p controls bud site localization. We demonstrate that the GEF domain of Sdc25p is closely related to that of Cdc25p. We first constructed a thermosensitive allele of SDC25 by specifically altering amino acid positions known to be changed in the cdc25-1 mutation. Secondly, we constructed three chimeric genes from CDC25 and SDC25, the products of which are as active in the Ras pathway as are the wild-type proteins. In contrast, similar chimeras made between CDC25 and BUD5 lead to proteins that are inactive both in the Ras and budding control pathways. This difference in the ability of chimeric proteins to retain activity allows us to define two subclasses of structurally different GEFs: Cdc25p and Sdc25p are Ras-specific GEFs, and Bud5p is a putative GEF for the Rsr1/Bud1 Rap-like protein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 245 (1994), S. 323-333 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; mRNA decay Poly(A) tail ; Ty transposition ; SSM4 gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Decay rates of mRNAs depend on many elements and among these, the role of the poly(A) tail is now well established. In the yeast Saccharomyces cerevisiae, thermosensitive mutations in two genes, RNA14 and RNA15, result in mRNAs having shorter poly(A) tails and reduced half-life. To identify other components interacting in the same process, we have used a genetic approach to isolate mutations that suppress the thermosensitivity of an rna14 mutant strain. Mutations in a single locus, named SSM4, not only suppress the cell growth phenotype but also the mRNA instability and extend the short mRNA poly(A) tails. The frequency of appearance and the recessive nature of these mutations suggested that the suppressor effect was probably due to a loss of function. We failed to clone the SSM4 gene directly by complementation, owing to its absence from gene banks; it later emerged that the gene is toxic to Escherichia coli, but we have nevertheless been able to clone the SSM4 sequence by Ty element transposition tagging. Disruption of the SSM4 gene does not affect cell viability and suppresses the rna14 mutant phenotypes. The protein encoded by the SSM4 gene has a calculated molecular mass of 151 kDa and does not contain any known motif or show homology with known proteins. The toxicity of the SSM4 gene in E. coli suggests that a direct biochemical activity is associated with the corresponding protein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 242 (1994), S. 257-262 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Protein phosphatase ; Ras-cAMP pathway ; DIS2S1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Saccharomyces cerevisiae DIS2S1/GLC7 gene encodes a type 1 protein phosphatase indispensable for cell proliferation. We found that introduction of a multicopy DIS2S1 plasmid impaired growth of cells with reduced activity of the cAMP-dependent protein kinase. In order to understand further the interaction between the two enzymes, a temperature-sensitive mutation in the DIS2S1 gene was isolated. The mutant accumulated less glycogen than wild type at the permissive temperature, indicating that activity of the Dis2s1 protein phosphatase is attenuated by the mutation. Furthermore, the dis2s1 ts mutation was shown to be suppressed by a multicopy plasmid harboring PDE2, a gene for cAMP phosphodiesterase. These results indicate that the Ras-cAMP pathway interacts genetically with the DIS2S1/GLC7 gene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Transcriptional activator ; AP-1 ; Stress response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Saccharomyces cerevisiae YAP2 gene encoding an AP-1-like transcriptional activator protein was cloned by selection for genes that confer pleiotropic drug resistance when present in high copy number. The novel YAP2 gene encodes a protein of 45827 daltons and is homologous in part to a known transcriptional activator protein encoded by YAP1/PDR4/SNQ3/PAR1. Homology was found only in both terminal regions. The N-terminal portion contains a region rich in basic amino acids, followed by a “leucine zipper” motif. Overexpression of YAP2 led to the induction of expression of an AP-1 recognition element (ARE)-dependent promoter. The yap1 disruptant has been shown to be sensitive to H2O2. In this study, we demonstrated that the yap1 disruptant is also unable to grow in medium containing 150 μM cadmium, whereas the yap2 disruptant exhibited no significant phenotypes. However, YAP2 in high copy number did suppress cadmium sensitivity, but not H2O2 sensitivity of the yap1 disruptant. YAP1 was able to mediate both cadmium- and H2O2-induced transcriptional activation of an ARE-dependent promoter. A high-copy-number plasmid bearing YAP2 mediated cadmium-induced transcriptional activation of this promoter. The inductions were prevented by the antioxidant N-acetyl-l-cysteine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 242 (1994), S. 289-296 
    ISSN: 1617-4623
    Schlagwort(e): DNA polymerases ε and δ ; 3′ → 5′ Exonuclease ; Replication errors ; Spontaneous mutations ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract DNA polymerases II (ε) and III(δ) are the only nuclear DNA polymerases known to possess an intrinsic 3′ → 5′ exonuclease in Saccharomyces cerevisiae. We have investigated the spontaneous mutator phenotypes of DNA polymerase δ and ε 3′ → 5′ exonuclease-deficient mutants, pol3-01 and pol2-4, respectively. pol3-01 and pol2-4 increased spontaneous mutation rates by factors of the order of 102 and 101, respectively, measured as URA3 forward mutation and his7-2 reversion. Surprisingly, a double mutant pol2-4 pol3-01 haploid was inviable. This was probably due to accumulation of unedited errors, since a pol2-4/pol2-4 pol3-01/pol3-01 diploid was viable, with the spontaneous his7-2 reversion rate increased by about 2 × 103-fold. Analysis of mutation rates of double mutants indicated that the 3′ → 5′ exonucleases of DNA polymerases δ and ε can act competitively and that, like the 3′ → 5′ exonuclease of DNA polymerase δ the 3′ → 5′ exonuclease of DNA polymerase ε acts in series with the PMS1 mismatch correction system. Mutational spectra at a URA3 gene placed in both orientations near to a defined replication origin provided evidence that the 3′ → 5′ exonucleases of DNA polymerases δ and ε act on opposite DNA strands, but were in sufficient to distinguish conclusively between different models of DNA replication.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 242 (1994), S. 297-304 
    ISSN: 1617-4623
    Schlagwort(e): Repetitive sequences ; Sequence variability ; Satellite DNA evolution ; Coleoptera ; X70332
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Satellite DNA is highly abundant in Alphitobius diaperinus (Tenebrionidae, Coleoptera), comprising 25% of the total genomic DNA. Sequence analysis reveals an average GC content of 50.8% and the presence of three different groups of satellite monomer variants, tH1, tH2 and tH3 with corresponding lengths of 123, 128 and 126 bp. Their mutual homologies range between 65 and 81 %. Sequence comparison shows that the monomer variant tH2 has been formed by a recombination process between tH1 and tH3, which have a low average homology of only 65.15%. The longest stretch of 100% homology between the recombining units is 17 bp and is located 3′ to the predicted recombination site. There is also an indication from sequence analysis that replication slippage and gene conversion play a part in the formation of satellite units and contribute to their divergence. The tH1, tH2 and tH3 monomer variants are organized in higher order repeating structures: a dimer, composed of tH1, and tH3, and a trimer containing tH1, tH2 and tH3 in series. The dimeric and trimeric repeat units furthermore create three higher order satellite subfamilies. Two of them contain either tandemly arranged dimers or trimers, while the third one is composed of both types of repeats, mutually interspersed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 253-260 
    ISSN: 1617-4623
    Schlagwort(e): Recombinant DNA ; Saccharomyces cerevisiae ; Endo-β-glucanase ; Endo-xylanase ; Heterologous expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have developed a method for fast and efficient isolation of enzyme genes from filamentous fungi by combining the ability of Saccharomyces cerevisiae to express heterologous genes with the utilisation of sensitive and reliable enzyme assays. A cDNA library from the fungus Humicola insolens was constructed in a S. cerevisiae/Escherichia coli shuttle vector in E. coli. Sub-pools of the library were subsequently screened for enzyme activity in S. cerevisiae. More than 130 clones were identified as positive in either an endo-β-glucanase or an endo-xylanase assay. Based on a partial characterization of the DNA sequence of the individual clones, they could be grouped into five distinct types of endo-β-glucanases and three types of endo-xylanases. A representative cDNA from each type was sub-cloned in an Aspergillus vector and expressed in A. oryzae. The new cloning method may be an important alternative to traditional cloning methods based on amino acid sequence information.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 308-314 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Integrative plasmids ; Recombinational structures ; UV irradiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nature of UV-induced pre-recombinational structures was studied using transformation of Saccharomyces cerevisiae cells with non-replicative plasmids. Transformation by double-stranded plasmids irradiated with UV was stimulated up to 50-fold, and both plasmid integration and conversion of the mutated chromosomal selective gene were found to be equally increased. The stimulation observed with such ‘totally’ irradiated plasmids was not found with plasmids bearing lesions in only one strand. This effect is attributed to the formation by excision repair of recombinogenic structures consisting of a pyrimidine dimer opposite a gap. When single-stranded integrative plasmids were irradiated, their transforming potential was decreased but the proportion of transformants that arose by gene conversion, rather than by plasmid integration, was increased from 8% to 49% as a function of the UV dose. Possible reasons why single-strand UV lesions favour gene conversion are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 243 (1994), S. 622-630 
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; Yeast Catabolite repression ; Gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Maltose utilization in yeast requires the presence of any one of the five unlinked, homologous MAL loci. Transcription of the two structural genes MALT (permease) and MALS (maltase) is induced by maltose and catabolite-repressed by glucose. MAL6T and MAL6S share a common 5′ intergenic sequence; deletion studies within this sequence revealed a bi-directionally functioning upstream activation sequence (UASM) consisting of four 11bp homologous sites. Activation of these sites by the MALR protein results in the coordinate expression of MAL6T and MAL6S. The basal promoter activates MALS expression to a greater extent than MALT and is located in a region that overlaps UASM. Deletion of several subsites within the UASM has an asymmetric effect on MAL gene expression, having a greater affect on MALT than on MALS. Catabolite repression of MAL6T and MAL6S by glucose is controlled at several levels. Using disruption mutants, the positively acting MAL1R protein was also found to play a role in catabolite repression of MAL6T and MAL6S.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    ISSN: 1617-4623
    Schlagwort(e): Saccharomyces cerevisiae ; RPK1 gene ; Protein kinase ; DNA replication ; Initiation of mitosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We report here the sequence of RPK1 (for Regulatory cell Proliferation Kinase), a new Saccharomyces cerevisiae gene coding for a protein with sequence similarities to serine/threonine protein kinases. The protein sequence of 764 amino acids includes an amino-terminal domain (residues 1–410), which may be involved in regulation of the kinase domain (residues 411–764). The catalytic domain of Rpkl is not closely related to other known yeast protein kinases but exhibits strong homology to a newly discovered group of mammalian kinases (PYT, TTK, esk) with serine/threonine/tyrosine kinase activity. Null alleles of RPK1 are lethal and thus this gene belongs to the small group of yeast protein kinase genes that are essential for cell growth. In addition, eliminating the expression of RPK1 gives rise to the accumulation of non-viable cells with less than a 1 N DNA content suggesting that cells proceed into mitosis without completion of DNA synthesis. Therefore, the Rpkt kinase may function in a checkpoint control which couples DNA replication to mitosis. The level of the RPK1 transcript is extremely low and constant throughout the mitotic cycle. However it is regulated during cellular differentiation, being decreased in α-factor-treated a cells and increased late in meiosis in a/α diploids. Taken together, our results suggest that Rpk1 is involved in a pathway that coordinates cell proliferation and differentiation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    ISSN: 1573-1561
    Schlagwort(e): Semiochemicals pheromones ; Dryocoetes affaber ; Dryocoetes confusus ; Coleoptera ; Scolytidae ; enantiomers ; diastereoisomers ; exo-brevicomin ; endo-brevicomin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Chemical analysis of whole body extracts and volatiles produced by feeding malesDryocoetes affaber (Mann.) disclosed (+)-exo-brevicomin and (+)-endo-brevicomin [(+)EXOB and (+)ENDOB], as the major insect-produced potential pheromones. Laboratory bioassays and field-trapping experiments demonstrated that (+)ENDOB is the main pheromone component, and (-)ENDOB has an inhibiting effect. EXOB either as (+) or (±) appears to be a multifunctional pheromone. It has a synergistic effect in blends of EXOB and ENDOB in ratios up to 1:1, and it is inhibitory at higher ratios. (-)EXOB was inactive. The most attractive blend forD. affaber was a 1:2 blend of (+)EXOB and (+)ENDOB. When this blend was compared with a 9:1 blend, the best known blend forDryocoetes confusus Swaine, the responses by beetles of each of the two species were highly specific, providing evidence for pheromonal exclusion between the two congenerics. We conclude that the combined effect of chirality and the ratio of geometrical isomers of brevicomin determines both the level of response and the species-specificity of the chemical signal inD. affaber.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    ISSN: 1573-1561
    Schlagwort(e): Callosobruchus maculatus ; Coleoptera ; Bruchidae ; flightless form ; flight form ; tubular olfactometer ; walking behavior ; intermittent stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A comparison of the walking locomotory reactions of flightless and flight formCallosobruchus maculatus males when subjected to an air current scented with female sex pheromone was undertaken in a tubular olfactometer. The pheromone was delivered to the males either as short pulses or as a continuous flow. To analyze the males' reactions, three behavioral sequences were defined (sequence 1: male sensitivity/arousal; sequence 2: male reactivity; sequence 3; male progression and source location). Although flightless and flight form males were sensitive and reactive in all experiments, their locomotory displacement differed depending on the stimulus conditions. The flightless form males' response remained roughly the same whatever the stimulus conditions (i.e., they always reached the pheromone source). In contrast, the flight form males displayed a markedly reduced response when subjected to a continuous stimulation, indicating that intermittent on-off pheromone stimulation is required in order to sustain their upwind walking progress. This effect could be the result of sensory adaptation and/or habituation in the central nervous system of the flight form, requiring a flickering signal that is unnecessary for the flightless one.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Curculionidae ; Rhynchophorus cruentatus ; palmetto weevil ; S. palmetto ; aggregation pheromone ; 5-methyl-4-octanol ; cruentol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract 5-Methyl-4-octanol is the major aggregation pheromone of the palmetto weevil,Rhynchophorus cruentatus (F.). The pheromone (cruentol) was identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis of male-produced volatiles, coupled GC-mass spectrometry (MS) in electron impact and chemical ionization mode, and coupled GC-high resolution MS. In laboratory and field assays, a diastereomeric mixture of synthetic cruentol greatly enhanced attraction of weevils to cabbage palmetto,Sabal palmetto (Walter), stem tissue, indicating that cruentol and host volatiles are synergistically attractive. An attractive lure in combination with efficient traps should facilitate development of semiochemical-based management forR. cruentatus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 639-650 
    ISSN: 1573-1561
    Schlagwort(e): Soybean ; lipoxygenase ; peroxidase ; polyphenol oxidase ; trypsin inhibitor ; ascorbate oxidase ; oxidative stress ; Lepidoptera ; Noctuidae ; Helicoverpa zea ; corn earworm ; Cerotoma trifurcata ; bean leaf beetle ; Coleoptera ; Chrysomelidae ; Spissistilus festinus ; three-cornered alfalfa hopper ; Homoptera ; Membracidae ; induced resistance ; interspecific competition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Variation in induced responses in soybean is shown to be dependent, in part, upon herbivore species. Herbivory by the phloem-feeding three-cornered alfalfa hopper caused increases in the activities of several oxidative enzymes including lipoxygenases, peroxidases, ascorbate oxidase, and polyphenol oxidase. Bean leaf beetle defoliation caused increased lipoxygenase activity, but had little effect upon peroxidase, polyphenol oxidase, ascorbate oxidase, or trypsin inhibitor levels in either field or greenhouse studies. In one field experiment, prior herbivory by the bean leaf beetle subsequently reduced the suitability of foliage to the corn earwormHelicoverpa zea. The contribution of these findings to emerging theories of insect-plant interactions is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    ISSN: 1573-1561
    Schlagwort(e): Pissodes strobi ; white pine weevil ; Coleoptera ; Curculionidae ; Pinus strobus ; white pine ; plant vigor ; water stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Spring and fall adults of the white pine weevil,Pissodes strobi (Peck), were exposed in no-choice and two-choice tests to bark from water-stressed and non-water-stressed white pine (Pinus strobus L.), which had also been exposed or not exposed to weevil attack. This experiment demonstrated that the weevils could discriminate between bark from water-stressed white pine and preferred bark from the nonstressed plants. The weevils also preferred bark from nonstressed plants that were previously exposed to weevil damage. Spring and fall adults displayed the same feeding preferences. No sex differences were found in feeding preferences. Less nitrogen, phosphorus, and potassium were found in bark from the nonstressed plants, and the potassium level was higher in damaged plants. We expect that the biological performance of the weevil should be favored by vigorously growing plants rather than by stressed plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    ISSN: 1573-1561
    Schlagwort(e): Insects hydrocarbons ; alkanes ; Colorado beetle ; Leptinotarsa decemlineata Say ; Tribolium destructor ; Coleoptera ; Teneboionidae ; choysomelidae ; mass spectrometry ; linked scanning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Branched hydrocarbons were identified in the lipids ofLeptinotarsa decemlineata Say andTribolium destructor by gas chromatography, ordinary electron impact mass spectrometry, and linked, scanned, daughterion monitoring. This methodology allowed us to revise our earlier results based only on GC-MS data confirming the existence of only monomethyl-, dimethyl-, and trimethylalkanes in the hydrocarbons ofL. decemlineata Say. The hydrocarbons fromTribolium destructor consist ofn-alkanes, 3-methylalkanes, internally branched monomethylalkanes and dimethylalkanes. Daughter-ion monitoring can be particularly important for distinguishing between incidentally overlapped GC peaks of hydrocarbons from different series. A trace, for example, of dimethylalkane coeluating withn-alkane was easily identified in GC peak of hydrocarbon mixture ofT. destructor. Link scans confirmed also molecular weights for the compounds without molecular ions in the mass spectra. Structural assignment of the compounds were verified by comparison of the experimental and calculated values of the GC retention Kovats indexes (KI).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 10 (1994), S. 406-409 
    ISSN: 1573-0972
    Schlagwort(e): Bacillus cereus-diarrhoeal-type enterotoxin ; Bacillus thuringiensis ; Coleoptera ; Diptera ; Lepidoptera ; thuringiensin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract At moderate concentration, 23 of 40 strains of Bacillus thuringiensis isolated from Sweden were toxic to Trichoplusia ni and five were toxic to Aedes aegypti. Five of the strains were toxic to Diabrotica undecimpunctata at high concentration, two were toxic to Heliothis virescens at low concentration and five produced thuringiensin (formerly called β-exotoxin). No strain was toxic towards the beet armyworm Spodoptera exigua at low concentration. Twenty-three of the strains produced a B. cereus-diarrhoeal-type enterotoxin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 2513-2521 
    ISSN: 1573-1561
    Schlagwort(e): Semiochemicals ; kairomones ; ethylene ; ethrel ; Olea europaea ; olive tree ; Phloeotribus scarabaeoides ; Coleoptera ; Scolytidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In recently pruned olive logs, an increase in ethylene release has been observed between 48 and 72 hr after pruning. The values reached, as well as the duration of ethylene release, varied greatly from one log to another. PioneerPhloeotribus scarabaeoides females have shown a preference for logs in which ethylene emission was higher. In logs treated with ethrel, a significant increase in ethylene emission was observed, together with a greater period of release. Therefore, the use of logs treated with ethrel could be of great importance in the control of this pest of olive trees.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    ISSN: 1573-1561
    Schlagwort(e): Anomala vitis ; Anomala dubia ; chafer ; Coleoptera ; Scarabaeidae ; Melolonthidae ; Rutelinae ; attractant ; 2-(E)-nonen-1-ol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Traps baited with 2-(E)-nonen-1-ol alone or in combination with other compounds caught large numbers of males of both the vine chafer,Anomala vitis Fabr. and the margined vine chafer,A. dubia Scop. (Coleoptera: Scarabaeidae), vineyard and orchard pests. In a dosage test, the largest numbers were caught by traps baited with 10 mg of 2-(E)-nonen-1-ol, which was the highest dosage tested. This is the first report on male attractants for chafer species occurring in Europe.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 2611-2622 
    ISSN: 1573-1561
    Schlagwort(e): Ips pini ; Coleoptera ; Scolytidae ; repeatability ; female choice ; response phenotype ; bark beetle ; pheromone ; communication systems ; multiple measurements ; individual variation ; ipsdienol ; enantiomers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Repeatability, a measure of the proportion of variance in a character that occurs among rather than within individuals, is assessed for the phenotypic trait of female response preference for enantiomeric blends of ipsdienol inIps pini at two pheromone concentrations—1 µg and 5 μg of ipsdienol. Average female response shows greater repeatability at the higher pheromone dosage when females are tested in two successive sets of five assays than when assayed in three successive sets or at the lower dosage. Repeatability within each set of five assays is highest for the first set and decreases thereafter. Thus the response phenotype of females for enantiomeric blends of ipsdienol in this experiment is context dependent; female choice of an enantiomeric blend differed between dosages and among sets of assays.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scolytidae ; Dendroctonus brevicomis ; western pine beetle ; aggregation ; verbenone ; ipsdienol ; inhibitors ; antiaggregants ; doseresponse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The response of western pine beetle,Dendroctonus brevicomis Le Conte, to different release rates of the aggregation semiochemicals (attractants)exo-brevicomin, frontalin, and myrcene and the inhibitors verbenone and ipsdienol was investigated. Release rates of verbenone ranging from 0.18 mg/ 24 hr to 1.2 mg/24 hr did not result in significant reductions in mean trap catch ofD. brevicomis. In contrast, very low release rates of ipsdienol (0.02–0.4 mg/24 hr) significantly reduced trap catch compared to controls. The combination of verbenone and ipsdienol, released at rates above 0.09 and 0.02 mg/24 hr, respectively, resulted in significantly lower trap catches ofD. brevicomis in attractant-baited traps. Results of an experiment testing a factorial combination of different release rates of verbenone and attractants suggest that response is not ratio-specific. The response curve ofD. brevicomis to the levels of verbenone was similar across all levels of attractants, while the response to equivalent ratios of attractants to verbenone was not similar, suggesting that the behavior of the beetles is primarily influenced by the absolute release rate of verbenone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 3207-3219 
    ISSN: 1573-1561
    Schlagwort(e): Aggregation pheromone ; triene ; tetraene ; hydrocarbon ; Coleoptera ; Nitidulidae ; Carpophilus davidsoni ; Australian sap beetle ; trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A male-produced aggregation pheromone was identified for the Australian sap beetle,Carpophilus davidsoni Dobson (Coleoptera: Nitidulidae), by bioassay-guided fractionation of volatiles collected from feeding beetles. The most abundant components were: (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene, (3E,5E,7E)-6-ethyl-4-methyl-3,5,7-decatriene, (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-undecatetraene, and (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-undecatetraene. The relative abundance of these components in collections from individual males feeding on artificial diet was 100:7:9:31, respectively. Pheromone production began within several days after males were placed onto diet medium and continued for at least 20 weeks. Peak production was 〉3 µg total pheromone per male per day. Males in groups of 50–60 emitted less pheromone (the peak level was 0.09 µg per beetle per day), and the emissions from groups contained relatively little tetraene (proportions of the components listed above were 100:7:2:7, respectively). Three additional trienes and one additional tetraene were identified in minor amounts; the entire eight-component male-specific blend is qualitatively identical and quantitatively similar to that of the North American sibling species,C. freemani Dobson. A synthetic blend of the four major components on rubber septa, prepared to emit in the same proportions as from individual males, was highly attractive in the field when synergized with fermenting whole-wheat bread dough. Cross-attraction was observed in the field involving the pheromones ofC. davidsoni, C. hemipterus (L.), andC. mutilatus Erichson. Potential uses of the pheromones in pest management are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 3335-3344 
    ISSN: 1573-1561
    Schlagwort(e): Diabrotica virgifera virgifera ; fatty acids ; linoleic acid ; oleic acid ; stearic acid ; semiochemical ; attractants ; western corn rootworm ; host location ; Coleoptera ; Chrysomelidae ; Zea mays ; kairomone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A bioassay-driven sequential fractionation scheme was used to isolate fractions of a crude dichloromethane maize seedling extract behaviorally active to larvae of the western corn rootworm,Diabrotica virgifera virgifera LeConte. (Z,Z)-9,12-Octadecadienoic (linoleic) acid, (Z)-9-octadecenoic (oleic) acid, and octadecanoic (stearic) acid were identified from a purified fraction of maize extract that was attractive to western corn rootworm larvae in choice tests with equal levels of carbon dioxide on both sides of the choice. When synthetic linoleic, oleic, and stearic acids were tested together in the amounts and proportions found in the attractive fraction (1000, 800, and 300 ng of linoleic, oleic, and stearic acids, respectively), significantly more western corn rootworm larvae were found on the side with synthetic free fatty acids plus carbon dioxide than on the side with carbon dioxide alone. Results of the choice-test bioassays were not significantly different when the synthetic blend of free fatty acids was substituted for the purified maize fraction. Neither the purified extract nor the synthetic blend was behaviorally active in preliminary single-choice experiments without carbon dioxide. Linoleic, oleic, and stearic acids were also tested individually in the choice test bioassay with carbon dioxide on both sides of the choice to determine a dose-response curve. Linoleic and oleic acid each had one dose that was significantly attractive in conjunction with carbon dioxide on both sides of the choice, but stearic acid was not active in the doses tested.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 555-568 
    ISSN: 1573-1561
    Schlagwort(e): Oreina spp. ; Coleoptera ; Chrysomelidae ; larval defense ; cardenolides ; pyrrolizidine alkaloids ; sequestration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Adult leaf beetles of the genusOreina are known to be defended either by autogenously produced cardenolides or by pyrrolizidine alkaloids (PAs) sequestered from the food plant, or both. In this paper we analyze larvae of differentOreina species and show that the larvae contain the same defensive toxins as the adults in quantities similar to those released in the adults' secretion. Both classes of toxins are found in the body and hemolymph of the larvae, despite their different origins and later distribution in the adults. Larvae of sequestering species differed in their PA patterns, even though they fed on the same food plants. The concentration in first-instar larvae of a PA-sequestering species was similar to that in fourth-instar larvae. In all stages examined, the amount of PAs per larva did not greatly exceed the estimated uptake of one day. Eggs of two oviparous species contained large concentrations of the adult's toxins, while neonates of a sequestering larviparous species had no PAs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Rhynchophorus phoenicis ; Elaeis quineensis ; kairomone ; synergism ; oil palm ; palm weevil ; palm volatiles ; host selection ; primary attraction ; aggregation pheromone ; 3-methyl-octan-4-ol ; ethyl acetate ; ethyl propionate ; isobutyl propionate ; ethyl butyrate ; ethyl isobutyrate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Small trunk pieces of a freshly felled 10-year-old oil palm,Elaeis quineensis (Jacq.), were placed in a modified Nalgene desiccator, and volatiles captured for six days on Porapak Q. Gas chromatographic (GC) analysis of Porapak-Q-trapped volatiles with both flame ionization (FID) and electroantennographic detection (EAD) using male or femaleR. phoenicis antennae revealed several EAD-active compounds. They were identified as: ethyl acetate, ethyl propionate, isobutyl propionate, ethyl butyrate, and ethyl isobutyrate. In field experiments in the La Me Research Station, Côte d'Ivoire, ethyl propionate (50 mg/24 hr) but not all esters combined (50 mg/24 hr each) significantly increased capture ofR. phoenicis in pheromone-baited (3 mg/24 hr) traps. One kilogram of 1- to 3-day-old palm tissue was significantly more effective than ethyl propionate in enhancing pheromone attraction. Superior attraction of palm tissue may be attributed to additional as yet unknown semiochemicals. Alternatively, release rates and/or ratios of synthetic volatiles differed from those of palm tissue at peak attraction.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 979-989 
    ISSN: 1573-1561
    Schlagwort(e): Ceutorhynchus assimilis ; Coleoptera ; Curculionidae ; olfactometer ; sex pheromone ; aggregation pheromone ; electroantennogram
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The responses ofCeutorhynchus assimilis Payk. (Coleoptera, Curculionidae) to the odor of overwintered and new generation weevils were studied using an olfactometer, choice tests in a laboratory cage, field tests using sticky traps baited with live weevils, and by electroantennograms (EAG's). Unmated male weevils and, to a lesser extent, female weevils of the overwintered generation were attracted to the odor of live unmated over-wintered female weevils. New generation weevils exhibited no behavioral response to conspecific odor. Male and female weevils of the overwintered generation exhibited positive EAGs to hexane extracts of overwintered female weevils, whereas EAGs of new-generation weevils of either sex were unresponsive to these extracts. This suggests that the unmated female weevils from the overwintered generation produce a volatile chemical or chemicals that attracts unmated male and female weevils. The new generation of female weevils does not produce this attractive chemical before overwintering, and male and female weevils of this generation can not detect the chemical(s) via their antennal chemoreceptors until they have undergone their overwintering period.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    ISSN: 1573-1561
    Schlagwort(e): Aphanamixis polystachya ; pithraj ; repellent ; contact toxicity ; food protectant ; Callosobruchus chinensis ; Coleoptera ; Bruchidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Ground leaves, bark, seeds, and four seed extracts of pithraj,Aphanamixis polystachya (family Meliaceae), a locally grown plant in Bangladesh, were evaluated for their repellency, contact toxicity, and food protectant efficacy against adult pulse beetle (Callosobruchus chinensis L.). The seed extracts showed poor repellent effects, but high contact toxicity to adults at 72 hr after application. The ground leaves, bark, and seeds provided good protection for mung beans against pulse beetles, and the seed powder greatly reduced the F1 progeny and seed damage rates.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 991-1007 
    ISSN: 1573-1561
    Schlagwort(e): Leptinotarsa decemlineata ; Colorado potato beetle ; Coleoptera ; Chrysomelidae ; Solanum berthaultii ; glandular trichomes ; feeding deterrents ; host preference ; plant resistance to insects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Leaf rinses ofS. berthaultii PI 473334 with methylene chloride were deterrent to feeding by the Colorado potato beetle when applied toS. tuberosum tuber and leaf disks. When the leaf rinse was separated into its nonvolatile and volatile fractions and applied to tuber disks, the nonvolatile fraction was highly deterrent, while the volatile fraction reduced consumption, but not significantly compared to the controls. A hexane leaf rinse was not deterrent to feeding, while an acetone rinse was approximately twofold more deterrent than the methylene chloride rinse when applied to leaf disks. Three cycles of bioassay-guided, reversed-phase open-column fractionation of an acetone leaf rinse yielded a relatively polar fraction with low deterrent activity, and two nonpolar fractions exhibiting higher specific activity. Reversed-phase preparative HPLC of these fractions yielded seven active fractions among the 10 assayed. Subsequent analytical HPLC indicated that two fractions each contained a single UV-absorbing compound, while another represented a mixture of at least four compounds. The remaining fractions were composed of complex mixtures of possibly ionic or polymeric compounds that were poorly resolved by HPLC.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 1075-1093 
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Chrysomelidae ; Chrysomela lapponica ; larval secretion ; defense
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The defensive secretion ofChrysomela lapponica larvae, which is produced by nine pairs of exocrine dorsal glands, has been chemically analyzed. TheC. lapponica larvae were kept in the laboratory on leaves of either birch (Betula pendula), alder (Alnus glutinosa), or willow (Salix fragilis). Larvae developed normally on birch and willow, whereas those on alder died within a few days. GC-MS analyses of the secretion of larvae on birch and willow revealed that the composition of this secretion differs distinctly from the known ones of several otherChrysomela species feeding exclusively on Salicaceae. In the exocrine secretion of larvae on birch, 69 compounds were identified, which included the main components isobutyric acid, 2-methylbutyric acid, and esters of the two. Several of the esters have not been reported previously from nature. The alcoholic components of the esters may be hydrolysis products ofBetula glycosides. Most components of the secretion of larvae feeding on birch were also found in the secretion of larvae feeding on willow. In addition, major amounts of benzoic acid and salicylalcohol were present in the secretion of the larvae feeding on willow.C. lapponica obviously acquires salicylalcohol by hydrolysis of salicin from willow leaves. However, in contrast to otherChrysomela species,C. lapponica larvae oxidize only traces of salicylalcohol to salicylaldehyde. The repellent activity of single authentic compounds of the secretion of larvae feeding on birch and willow, respectively, was tested in laboratory bioassays with ants (Myrmica sabuleti). Biosynthetic pathways to some identified compounds are suggested and discussed under evolutionary and functional aspects.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    ISSN: 1573-1561
    Schlagwort(e): Bioassay ; red flour beetle ; Tribolium castaneum ; Coleoptera ; Tenebrionidae ; ECI ; Minthostachis mollis ; Melaleuca quinquenervia ; Sapindus saponaria ; α-pinene ; β-pinene ; eugenol ; kaurenic acid ; sparteine ; phagodepression ; phagostimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We designed a new bioassay to test plant extract activity against stored product pests. Plant compounds were added to feed disks composed of wheat flour and yeast and fed to the red flour bettle (Tribolium castaneum). By measuring insect mass, disk mass, and insect mortality over time it was possible to calculate a phagodepression index, an antifeedant index, the amount of treatment chemical ingested by the beetles, the mortality rate, and the efficiency of conversion of ingested food. The assay was performed for 60 hr to allow for possible habituation effects and to discriminate between phagodeterrency and physiological stress caused by treatments. α- and β-Pinene, eugenol, kaurenic acid, sparteine, essential oils ofMinthostachis mollis andMelaleuca quinquenervia, and extracts ofSapindus saponaria were tested. Using this assay we detected the presence of both phagodepressant and phagostimulant compounds inS. saponaria extracts, and we quantified the pronounced effects of sparteine onT. castaneum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    ISSN: 1573-1561
    Schlagwort(e): Coleoptera ; Scarabaeidae ; (R,Z)-5-(−)-oct-1-enyl)oxacyclopentan-2-one ; (R,Z)-5-(−)-(dec-1-enyl)oxacyclopentan-2-one ; (R,E)-5-(−)-(oct-1-enyl)oxacyclopentan-2-one ; Anomala albopilosa sakishimana ; Anomala octiescostata ; Anomala cuprea ; pheromone release ; GC-EAD
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Two components were identified in the sex pheromone system of the green chafter,Anomala albopilosa sakishimana Nomura: (R,Z)-5-(−)-(oct-1-enyl)oxacyclopentan-2-one (buibuilactone) and (R,Z)-5-(−)-(dec-1-enyl)oxyacyclopentan-2-one (japonilure), which have been previously identified as sex pheromone constituents ofA. cuprea andA. octiescostata. A female-specific minor component, (R,E)-5-(−)-(oct-1-enyl)oxacyclopentan-2-one, did not seem to be involved in pheromonal communication because it was not EAD active, but its role remained unclear. A synthetic blend of the two components captured significantly more beetles than any other treatments. Nevertheless, the fact that both the synthetic sex pheromone and field-captured female beetles were weak lures convinced us that the sex pheromone system may be only part of a complex communication system, probably involving plant volatiles. Although the sex pheromone was released during both the scotophase and photophase, there was an increase of 60% in the photophase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 20 (1994), S. 1697-1704 
    ISSN: 1573-1561
    Schlagwort(e): cis-3-Hexenyl acetate ; benzaldehyde ; phenylacetaldehyde ; benzyl alcohol ; phenethyl alcohol ; phenylacetonitrile ; benzyl benzoate ; anethol ; geraniol ; phenethyl propionate ; kairomone ; sex pheromone ; dandelion ; Taraxacum officionale ; Coleoptera ; Scarabidae ; Anomala oritescostata ; scarab beetle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The attraction of the scarab beetleAnomala octiescostata to dandelion,Taraxacum officinale, was demonstrated to be chemically mediated by a mixture ofcis-3-hexenyl acetate, benzaldehyde, phenylacetaldehyde, benzyl alcohol, phenethyl alcohol, phenylacetonitrile, and benzyl benzoate, in the ratio 4:8:14:3:5:19:11. Combination of the synthetic kairomone and sex pheromone (buibuilactone + japonilure, 8:2), significantly increased the total catches ofA. octiescostata. Catches of male (but not female) beetles were significantly higher with the kairomone-pheromone blend than with kairomone alone. The synergistic effect of the kairomone from dandelion on the attractiveness did not significantly differ from that of a food-type lure, anethol, geraniol, and phenethyl propionate (9:0.5:0.5). The latter combined with the synthetic sex pheromone resulted in better attraction of female (but not male)A. octiescostata than the sex pheromone alone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...