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  • 1
    ISSN: 1432-0983
    Keywords: Key words Citrinin ; Pet mutants ; Mitochondrial biogenesis ; Vacuolar ATPase ; YKL118W disruption ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In countries with a hot climate the mycotoxin citrinin represents a serious problem in fungal food-poisoning. In humans the renal system is affected the most and the mitochondrial respiratory chain was identified as a possible sensitive target for this toxin. In addition, citrinin has an antifungal activity that also inhibits the growth of the yeast Saccharomyces cerevisiae. So far the precise mode of action and the subcellular targets for citrinin have not been identified. Therefore, we decided to use the model organism yeast for a genetic approach to identify genes that play a role in the sensitivity against this mycotoxin. A large collection of conditional respiratory deficient yeast mutants was screened for sensitivity against citrinin. One special pet-ts mutant was identified that exhibited a higher sensitivity against citrinin. The genetic system of yeast allowed the isolation of the respective wild-type gene. This yeast gene encodes the Vph2p subunit that is essential for the correct assembly of the vacuolar ATPase. Isolation of the mutated gene and gene-disruption experiments of VPH2 and the partially overlapping small YKL118W gene verified this finding. The wild-type VPH2 gene restores all defects of the mutants. In contrast to this, YKL118W gave no complementation and the null mutant showed no phenotype. Thereby the yeast vacuolar ATPase was found to be important for the toxic effect of citrinin in yeast cells. The consequences of this finding for the molecular mechanism of citrinin action and its relation to the mitochondrial respiratory chain are discussed.
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  • 2
    ISSN: 1432-0983
    Keywords: Key words Translation release factors ; Chromosome stability ; Microtubules ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome stability in suppressor mutants for SUP35 and SUP45 genes coding for translation release factors was studied. We obtained spontaneous and UV-induced sup35 or sup45 mutants in a haploid strain disomic for chromosome III and tested the stability of an extra copy of this chromosome. The majority of the mutants showed increased chromosome instability. This phenotype was correlated with an increased sensitivity to the microtubule-poisoning drug benomyl which affects chromosome segregation at anaphase. Our data suggest that termination-translation factors eRF3 and eRF1 control chromosome transmission at mitotic anaphase in Saccharomyces cerevisiae.
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  • 3
    ISSN: 1437-5613
    Keywords: Key words Herbivory ; Plant–herbivore interaction ; Lepidoptera ; Cruciferous plants ; Vegetation texture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Correlation between plant size and reproductive output may be modified by herbivory in accordance with host plant density and the presence of nonhost plants. To elucidate the effects of nonhost plant density and host plant density on the intensity of herbivory and reproductive output of the host plant in relation to plant size under natural conditions, we investigated the abundance of three lepidopteran insects, Plutella maculipennis, Anthocharis scolymus, and Pieris rapae the intensity of herbivory, and fruit set of their host plant, Turritis glabra (Cruciferae). To elucidate the effects of nonhost and host plant density, we selected four categories of plots under natural conditions: low density of nonhost and high density of host plants; low density of both nonhost and host plants; high density of both nonhost and host plants; and high density of nonhost and low density of host plants. The plant size indicated by stem diameter was a good predictor of the abundance of all herbivorous species. The effects of density of nonhost and host plants on the abundance of insects varied among species and stages of insects. As the abundance of insects affected the intensity of herbivory, herbivory was more apparent on larger host plants in plots with low density of both nonhost and host plants. Consequently, the correlation between plant size and the number of fruits disappeared in low plots with density of both nonhost and host plants. In this T. glabra– herbivorous insect system, the density of nonhost plants and host plants plays an important role in modifying the relationship between plants and herbivores under natural conditions.
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  • 4
    ISSN: 1437-5613
    Keywords: Key words Community patterns ; Lepidoptera ; Route order ; Species richness ; Species distribution ; Environmental disturbance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Kitahara and Fujii, in 1994, analyzed the butterfly communities along a gradient of human disturbance by applying the generalist/specialist concept. Butterfly species were classified into generalist or specialist species based on their voltinism (seasonal time dimension) and potential larval resource breadth (food dimension). The community structure and species composition showed the systematic changes along the gradient. To verify the generality of those trends, we monitored five grassland butterfly communities with varying degrees of human disturbance twice a month during 1985 by the line transect method at the foot of Mt. Fuji, central Japan, and analyzed their structure in a manner similar to that employed by Kitahara and Fujii. Most results were consistent with the patterns recognized by Kitahara and Fujii. The route (community) order based on increasing human disturbance was strongly and negatively correlated with butterfly species richness but with neither butterfly species diversity (H′) nor evenness (J′). Also, the degree of human disturbance was significantly and negatively correlated with the number of specialist species, but not with that of generalists, in a community. Butterfly species richness was more strongly correlated with the number of specialist species than with that of generalists. Our analyses also showed that the generalist species were distributed more widely over the communities than were the specialists. However, in contrast to the trend revealed by Kitahara and Fujii, there was no significant difference in the population densities and in the spatial population variability between the two species groups. As a whole, our analyses confirmed the consistency of most community patterns detected by Kitahara and Fujii. The causes of the inconsistencies in some patterns were thought to be mainly the present habitat conditions with a relatively short growing season at high altitudes.
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  • 5
    ISSN: 1432-0983
    Keywords: Key wordsPOL32 ; SRS2 ; DNA repair ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pol32 is a subunit of Saccharomyces cerevisiae DNA polymerase δ required in DNA replication and repair. To gain insight into the function of Pol32 and to determine in which repair pathway POL32 may be involved, we extended the analysis of the pol32Δ mutant with respect to UV and methylation sensitivity, UV-induced mutagenesis; and we performed an epistasis analysis of UV sensitivity by combining the pol32Δ with mutations in several genes for postreplication repair (RAD6 group), nucleotide excision repair (RAD3 group) and recombinational repair (RAD52 group). These studies showed that pol32Δ is deficient in UV-induced mutagenesis and place POL32 in the error-prone RAD6/REV3 pathway. We also found that the increase in the CAN1 spontaneous forward mutation of different rad mutators relies entirely or partially on a functional POL32 gene. Moreover, in a two-hybrid screen, we observed that Pol32 interacts with Srs2, a DNA helicase required for DNA replication and mutagenesis. Simultaneous deletion of POL32 and SRS2 dramatically decreases cellular viability at 15 °C and greatly increases cellular sensitivity to hydroxyurea at the permissive temperature. Based on these findings, we propose that POL32 defines a link between the DNA polymerase and helicase activities, and plays a role in the mutagenic bypass repair pathway.
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  • 6
    ISSN: 1617-4623
    Keywords: Key words DNA repair ; Helix-hairpin-Helix motif ; Methylmethane sulfonate (MMS) ; Saccharomyces cerevisiae ; UV radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gene MUS81 (Methyl methansulfonate, UV sensitive) was identified as clone 81 in a two-hybrid screen using the Saccharomyces cerevisiae Rad54 protein as a bait. It encodes a novel protein with a predicted molecular mass of 72,316 (632 amino acids) and contains two helix-hairpin-helix motifs, which are found in many proteins involved in DNA metabolism in bacteria, yeast, and mammals. Mus81p also shares homology with motifs found in the XPF endonuclease superfamily. Deletion of MUS81 caused a recessive methyl methansulfonate- and UV-sensitive phenotype. However, mus81Δ cells were not significantly more sensitive than wild-type to γ-radiation or double-strand breaks induced by HO endonuclease. Double mutant analysis suggests that Rad54p and Mus81p act in one pathway for the repair of, or tolerance to, UV-induced DNA damage. A complex containing Mus81p and Rad54p was identified in immunoprecipitation experiments. Deletion of MUS81 virtually eliminated sporulation in one strain background and reduced sporulation and spore viability in another. Potential homologs of Mus81p have been identified in Schizosaccharomyces pombe, Caenorhabditis elegans and Arabidopsis thaliana. We hypothesize that Mus81p plays a role in the recognition and/or processing of certain types of DNA damage (caused by UV and MMS) during repair or tolerance processes involving the recombinational repair pathway.
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  • 7
    ISSN: 1617-4623
    Keywords: Key words Autonomously replicating sequence (ARS) ; Anti-bent DNA ; DNA structure ; Replication origin ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to better understand the involvement of the DNA molecule in the replication initiation process we have characterized the structure of the DNA at Autonomously Replicating Sequences (ARSs) in Saccharomyces cerevisiae. Using a new method for anti-bent DNA analysis, which allowed us to take into account the bending contribution of each successive base plate, we have investigated the higher-order structural organization of the DNA in the region which immediately surrounds the ARS consensus sequence (ACS). We have identified left- and right-handed anti-bent DNAs which flank this consensus sequence. The data show that this organization correlates with an active ACS. Analysis of the minimum nucleotide sequence providing ARS function to plasmids reveals an example where the critical nucleotides are restricted to the ACS and the right-handed anti-bent DNA domain, although most of the origins considered contained both left- and right-handed anti-bent DNAs. Moreover, mutational analysis shows that the right-handed form is necessary in order to sustain a specific DNA conformation which is correlated with the level of plasmid maintenance. A model for the role of these individual structural components of the yeast replication origin is presented. We discuss the possible role of the right-handed anti-bent DNA domain, in conjunction with the ACS, in the process of replication initiation, and potentialities offered by the combination of left- and right-handed structural components in origin function.
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  • 8
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    Molecular genetics and genomics 263 (2000), S. 877-888 
    ISSN: 1617-4623
    Keywords: Key words Staurosporine ; Vacuolar-type proton pumping ATPase ; Vacuolar protein sorting ; ATP-binding cassette transporter ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mutations at several loci affect the sensitivity of the yeast Saccharomyces cerevisiae to staurosporine. We report here the characterization of novel staurosporine- and temperature-sensitive mutants (stt). Cloning and integration mapping showed that the genes STT2/STT6, STT5, STT7, STT8 and STT9 are allelic to VPS18, ERG10, GPI1, VPS34 and VPS11, respectively. The products of ERG10 and GPI1, respectively, catalyze mevalonate and glycosyl phosphatidylinositol anchor synthesis, while VPS18 and VPS11 genes belong to the class C VPS (Vacuolar Protein Sorting) genes, and the VPS34 gene is classified as a class D VPS. Therefore, staurosporine sensitivity is affected by ergosterol and glycolipid biosynthesis and by vacuolar functions. We found that other vps mutants belonging to classes C and D exhibit staurosporine sensitivity, and that they show calcium sensitivity and fail to grow on glycerol as the sole carbon source; both of the last two characteristics are shared by vacuolar H+-ATPase mutants (vma). As vma mutants were also found to show staurosporine-sensitive growth, staurosporine sensitivity is likely to be affected by acidification of the vacuole. Moreover, wild type yeast cells are more sensitive to staurosporine in alkaline media than in acidic media, suggesting that staurosporine is exported from the cytosol by H+/drug antiporters. Pleiotropic drug resistance (PDR) genes also provide some resistance to staurosporine, because Δpdr5, Δsnq2 and Δyor1 strains are more sensitive to staurosporine than the wild-type strain. This suggests that staurosporine is also exported by the ATP-binding cassette (ABC) transporters on the plasma membrane. vma mutants and vps mutants of classes C and D vps are sensitive to hygromycin B and vanadate, while ABC transporter-depleted mutants do not show such sensitivity, indicating that two systems differ in their ability to protect the cell against different types of drug.
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  • 9
    ISSN: 1617-4623
    Keywords: Key wordsGAL regulon ; Transcription ; Saccharomyces cerevisiae ; Galactose suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A plasmid clone that suppresses galactose toxicity in a gal7 yeast strain has been isolated from a multicopy genomic DNA library. Molecular analysis revealed that the region responsible for the suppression of galactose toxicity corresponds to the ORF YPR030w, which was named MRG19. A CEN-based plasmid carrying the above ORF was unable to suppress the toxicity. Galactokinase activity was substantially reduced in cell extracts obtained from transformants bearing multiple copies of MRG19. Multiple copies of MRG19 were also able to suppress galactokinase expression driven by the CYC1 promoter but not the TEF1 promoter. Multiple copies of MRG19 could not suppress GAL1-driven galactokinase expression in a gal80 strain. However, MRG19-mediated suppression of CYC1-driven galactokinase expression was independent of GAL80 function. These results imply that multiple copies of MRG19 suppress galactokinase expression probably at the level of transcription. In agreement with this idea, multiple copies of MRG19 also suppress β-galactosidase expression driven by the GAL1 promoter in a GAL80-dependent manner. Disruption of MRG19 leads to an increase in the cell density at stationary phase in synthetic complete medium. MRG19 encodes a previously uncharacterised 124-kDa protein that shows no sequence homology to any known proteins.
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  • 10
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    Molecular genetics and genomics 263 (2000), S. 81-89 
    ISSN: 1617-4623
    Keywords: Key words Flp recombinase ; Site-specific recombination ; Homologous recombination ; RAD52 ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Site-specific recombination within the Saccharomyces cerevisiae 2-micron DNA plasmid is catalyzed by the Flp recombinase at specific Flp Recognition Target (FRT) sites, which lie near the center of two precise 599-bp Inverted Repeats (IRs). However, the role of IR DNA sequences other than the FRT itself for the function of the Flp reaction in vivo is not known. In the present work we report that recombination efficiency differs depending on whether the FRT or the entire IR serves as the substrate for Flp. We also provide evidence for the involvement of the IR in RAD52-dependent homologous recombination. In contrast, the catalysis of site-specific recombination between two FRTs does not require the function of RAD52. The efficiency of Flp site-specific recombination between two IRs cloned in the same orientation is about one hundred times higher than that obtained when only the two FRTs are present. Moreover, we demonstrate that a single IR can activate RAD52-dependent homologous recombination between two flanking DNA regions, providing new insights into the role of the IR as a substrate for recombination and a new experimental tool with which to study the molecular mechanism of homologous recombination.
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  • 11
    ISSN: 1617-4623
    Keywords: Key wordsYarrowia lipolytica ; Saccharomyces cerevisiae ; Ambient pH signalling ; Signal transduction ; Transmembrane protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Yarrowia lipolytica, the transcription factor Rim101p mediates both pH regulation and control of mating and sporulation. Like its homologues PacC of Aspergillus nidulans and Rim101p of Saccharomyces cerevisiae, YlRim101p is activated by proteolytic C-terminal processing, which occurs in response to a signal transduced by a pathway involving several PAL gene products. We report here the cloning and sequencing of two of these genes, PAL2 and PAL3. PAL2 encodes a putative 632-residue protein with six possible transmembrane segments, which differs from the transmembrane proteins Rim9p of S. cerevisiae and PalI of A. nidulans, but is homologous to A. nidulans PalH and to the product of the ORF YNL294c, a predicted polypeptide of unknown function in S. cerevisiae. PAL3 encodes an 881-residue polypeptide that is homologous to PalF of A. nidulans and to a newly identified putative polypeptide of S. cerevisiae. Both PAL2 and PAL3 are expressed constitutively, regardless of ambient pH. Mutations in these genes affect growth at alkaline pH and sporulation in both Y. lipolytica and in S. cerevisiae. They affect invasiveness of haploid strains in S. cerevisiae only, and conjugation in Y. lipolytica only. These results highlight the conservation of the Pal pathway initially described in A. nidulans.
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  • 12
    ISSN: 1573-8248
    Keywords: biological control ; blueberry ; egg parasitoid ; inundative release ; leafroller ; Lepidoptera ; Tortricidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inundative releases of Trichogramma minutum Riley were made in a commercialblueberry field in British Columbia, Canada, todetermine the extent of dispersal of adult wasps, andto determine whether complete parasitism of eggswithin egg masses of the target host [oblique-bandedleafroller (OBLR), Choristoneura rosaceana(Harris)] occurred. Three weekly releases of waspswere made from a single release point in the center ofeach field during the flight of first generation OBLRadults. Sticky trap, sentinel egg mass andtarget-host egg mass data all indicated only a limitedrange of dispersal of T. minutum within thefield. In addition, only partial parasitism of eggmasses of the target host occurred even in closeproximity to the release point. We discuss theimportance of determining the response of Trichogramma females to previously-parasitized eggswhen using Trichogramma wasps for biologicalcontrol of lepidopterous species that oviposit largeegg masses.
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  • 13
    ISSN: 1573-8248
    Keywords: bird predation ; forest ; interference ; Italy ; Lepidoptera ; pine processionary caterpillar ; parasitism,/kwd〉 ; Pinus ; Thaumetopoeidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The hoopoe (Upupa epops L.) is an insectivorousbird often preying on larvae and pupae of the pineprocessionary caterpillar (Thaumetopoeapityocampa Denis & Schiffermüller), the mostimportant defoliator of pines in Southern Europe andNorthern Africa. The first half of the breeding seasonof this migratory bird coincides with the pupal stageof the insect. Bird predation of pupae was quantifiedin two years in a Pinus nigra stand of northernItaly by periodic counting of the empty cocoons lefton the soil surface after extraction. The predationrate, estimated on 20 pupation sites representing thewhole stand, was 74.1% in 1993 and 68.3% in 1994.Predation was higher in the upper part of the soil andthen progressively decreased with increasing depth.The hoopoe may also prey on cocoons containing pupaeinfected by pathogenic fungi or parasitoids. Anexclosure experiment showed that the bird mayinterfere with these other mortality factors. Threepupal parasitoids, the ichneumonids Erigorgusfemorator Aubert and Coelichneumon rudis (Boyerde Fonscolombe) and the pteromalid Conomoriumpityocampae Graham, were significantly less frequentin the exposed sites. The fungus Beauveriabassiana (Balsamo) Vuillemin and the most abundantpupal parasitoid, Villa brunnea Becker (Diptera:Bombyliidae), caused the highest pupal mortality atboth protected and exposed sites. The bird seems to bean incompletely additive mortality factor acting onthe pest and it can also alter the relativemortalities imposed by the other natural enemies.
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  • 14
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    Current genetics 38 (2000), S. 264-270 
    ISSN: 1432-0983
    Keywords: Key words Endopolygalacturonase ; Saccharomyces cerevisiae ; Kluyveromyces marxianus ; Pectinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gene encoding endopolygalacturonase (EC 3.2.1.15) has been cloned, sequenced and expressed from three strains of Saccharomyces cerevisiae (including non-secretors) and three strains of Kluyveromyces marxianus. Both control and coding regions showed small differences within each species, one including loss of a potential glycosylation site. Two non-secreting S. cerevisiae strains (FY1679 and var. uvarum) had non-transcribed copies of functional genes. Maximum enzyme activity was achieved with the S. cerevisiae FY1679 gene in an expressing vector, with an enzyme activity of 51 μmol of reducing sugar released from polygalacturonic acid μg protein−1 min−1, the highest so far reported for a yeast.
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  • 15
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    Oecologia 122 (2000), S. 1-10 
    ISSN: 1432-1939
    Keywords: Key words Distribution ; Gregariousness ; Larval strategy ; Lepidoptera ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Group-living in animal populations has many possible ecological and evolutionary explanations, including predator evasion and feeding facilitation. In insects, the thermal balance of solitary and gregarious larvae is likely to differ and may thus have important ecological consequences. The abilities of the larvae of four species of nettle-feeding nymphalid butterflies to thermoregulate were quantified in the field. Larval surface body temperatures of the gregarious Aglais urticae (small tortoiseshell) and Inachis io (peacock) and the solitary Polygonia c-album (comma) and Vanessa atalanta (red admiral) were measured for each instar, in both sunny and overcast conditions, over a seasonal range of temperatures. The results suggested two distinct larval thermal strategies. In the presence of direct sunlight, the exposed gregarious larvae of A. urticae and I. io regulated body temperatures at 32.5 and 31.5°C, respectively, while the temperatures of concealed larvae of P. c-album and V. atalanta were largely dependent on ambient temperatures. In the sun, the range of body temperatures recorded for A. urticae and I. io larvae was fairly narrow relative to ambient temperatures. This suggests a high degree of thermal control in these species. Modal body temperatures coincided with the temperature at which development rate is maximal. Regardless of whether changes in thermoregulation are a cause or consequence of the evolution of gregariousness, the combination of behavioural thermoregulation and gregariousness in larval insects has important implications for voltinism patterns and range extension (via increased development rates). Distributional responses of gregarious and solitary larvae to climatic warming may differ as a result of changes in cloud cover as well as changes in temperature.
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  • 16
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    Oecologia 122 (2000), S. 36-43 
    ISSN: 1432-1939
    Keywords: Key words Life history theory ; Longevity ; Ageing ; Mortality rate ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Life history theory predicts that organisms should only invest resources into intrinsic components of life span to the degree that it pays off in terms of reproductive success. Here, we investigate if the temporal distribution of mating opportunities may have influenced the evolution of intrinsic mortality rates in the butterfly Pararge aegeria (Satyrinae). In this species, females mate only once and the frequency of male mating opportunities depends on the temporal emergence pattern of virgin females. As expected, in a population from Madeira where females emerge continuously throughout the year, there was no sex difference in adult life span, while in a Swedish population with synchronised female emergence, males had significantly shorter life spans compared to females. A logistic mortality model provided the best fit to the observed change in age-specific mortality and all categories reached an asymptotic mortality rate of a similar magnitude. However, the Swedish males reached this mortality plateau more rapidly than the other categories. External mortality, due to water and food limitation, affected the pattern of sex-specific mortality but males from Sweden still had higher rates of mortality compared to all other categories. We argue that selection on male longevity is likely to be weaker in Sweden because under synchronised emergence, all females emerge and mate within a short period of time, after which male reproductive value will quickly approach zero. On Madeira, however, male reproductive value decrease more slowly with age since the probability of finding a receptive female is constant over the year.
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  • 17
    ISSN: 1572-8773
    Keywords: major facilitator superfamily ; iron transport ; siderophores ; enterobactin ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract While in fungi iron transport via hydroxamate siderophores has been amply proven, iron transport via enterobactin is largely unknown. Enterobactin is a catecholate-type siderophore produced by several enterobacterial genera grown in severe iron deprivation. By using the KanMX disruption module in vector pUG6 in a fet3Δ background of Saccharomyces cerevisiae we were able to disrupt the gene YOL158c Sce of the major facilitator super family (MFS) which has been previously described as a gene encoding a membrane transporter of unknown function. Contrary to the parental strain, the disruptant was unable to utilize ferric enterobactin in growth promotion tests and in transport assays using 55Fe-enterobactin. All other siderophore transport properties remained unaffected. The results are evidence that in S. cerevisiae the YOL158c Sce gene of the major facilitator super family, now designated ENB1, encodes a transporter protein (Enb1p), which specifically recognizes and transports enterobactin.
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  • 18
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    Entomologia experimentalis et applicata 97 (2000), S. 137-147 
    ISSN: 1570-7458
    Keywords: Etiella zinckenella ; Etiella hobsoni ; Lepidoptera ; Pyralidae ; soybean ; development ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments conducted in West Java, Indonesia investigated the developmental biology and reproductive behavior of two sympatric soybean pod borers, Etiella zinckenella Treitschke and E. hobsoni Butler (Lepidoptera: Pyralidae). It was determined that: (1) significant interspecific differences occurred between the egg, larval, pupal and total egg-to-adult developmental periods of laboratory raised E. zinckenella and E. hobsoni; (2) the pre-pupal and total egg-to-adult development periods of female E. zinckenella were significantly shorter than for males; (3) the longevity of virgin female E. zinckenella was significantly longer than that of virgin males, or virgin male and female E. hobsoni; (4) interspecific differences occurred in the female: male sex-ratios of laboratory raised adults; (5) peak mating for both species occurred on the second night after eclosion; (6) interspecific differences occurred in the temporal distribution of calling and mating behaviors; (7) repeated mating was observed for both species at a very low frequency; (8) interspecific mating did not occur; (9) female E. zinckenella were significantly more fecund than E. hobsoni; (10) the duration in copulo of E. zinckenella was significantly longer than that of E. hobsoni; and (11) wingtraps baited with virgin females caught only conspecific males, and reduced numbers of males were captured in traps simultaneously baited with virgin females of both species. This study demonstrates distinct biological differences and reproductive isolation between the two Etiella spp.
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  • 19
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; reproduction ; tebufenozide ; methoxyfenozide ; ecdysone agonist ; Argyrotaenia velutinana ; Choristoneura rosaceana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects on the fecundity and fertility of redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller,Choristoneura rosaceana (Harris), exposed as adults to surfaces treated with the ecdysone agonists tebufenozide (RH-5992) and methoxyfenozide (RH-2485) were examined. The first part of the study consisted of recently emerged moths being exposed to treated surfaces continuously throughout their lives (including mating and oviposition). Continuous exposure to tebufenozide- or methoxyfenozide-treated surfaces significantly reduced the mean number of eggs laid and the percent of eggs that hatched in both species. The second part of the study involved exposure of recently emerged virgin moths (by sex) to treated surfaces for 24 h, after which, the exposed moths were paired with a nontreated partner to mate and oviposit on nontreated surfaces. In this experiment, for A. velutinana, significant reductions in fecundity occurred only when the female was exposed to methoxyfenozide-treated surfaces. Significant reductions in A. velutinana egg fertility occurred with both male and female exposure in the methoxyfenozide treatments and only female exposure in the tebufenozide treatments. For C. rosaceana, significant reductions in fecundity occurred with both male and female exposure in the tebufenozide and methoxyfenozide treatments. Significant reductions in C. rosaceana egg fertility occurred with both male and female exposure in the tebufenozide treatments and only with female exposure in the methoxyfenozide treatments.
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  • 20
    ISSN: 1570-7458
    Keywords: calling behaviour ; periodicity ; sex pheromone ; attraction inhibitor ; attraction synergist ; field tests ; Lepidoptera ; Gracillariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females of the leaf miner moth Phyllonorycter acerifoliella (Z.) [=Ph. sylvella (Hw.)] and Ph. heegerella (Z.) (Lepidoptera: Gracillariidae: Lithocolletinae) release their sex pheromone at the beginning of photophase. The periodicity of the `calling' behaviour of Ph. acerifoliella females was established. Three compounds from calling virgin Ph. heegerella females were collected by the Solid Phase Micro Extraction (SPME) technique and identified as (Z)-8-tetradecenyl acetate (Z8-14:OAc), tetradecyl acetate (14:OAc) and (Z)-8-tetradecenol (Z8-14:OH) in the ratio (88±3):(2±0.6):(10±5) by capillary gas chromatography and mass spectrometry. Field trapping experiments demonstrated that the first two compounds are important for the attraction of conspecific males. Z8-14:OAc was found to be attractive when tested separately, while 14:OAc acted as synergist. The attractivity of the three component blend was reduced by 10% admixture of either (E)-10-dodecenyl acetate (E10-12:OAc) or (Z)-10-tetradecenyl acetate (Z10-14:OAc). Field tests of Z10-, Z8- and E10-14:OAc, identified from Ph. acerifoliella females, demonstrated that the first two compounds were essential for the attraction of conspecific males; so both are sex pheromone components. The attractivity of the three component blend of Z10- Z8- and E10-14:OAc was reduced by 10% admixture of (E)-10-dodecenol (E10-12:OH). The following four semiochemical compounds, Z8-14:OAc, Z8-14:OH, E10-14:OAc and 14:OAc, identified from phyllonoryctid females, as well as two sex attraction antagonists for Ph. acerifoliella and Ph. heegerella males, E10-12:OAc and Z10-14:OAc, are new for the family Gracillariidae. The results of field trapping experiments revealed mechanisms ensuring the specificity of the chemocommunication systems in Ph. acerifoliella, Ph. heegerella and Ph. ulmifoliella (Hb.) moths.
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  • 21
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    Entomologia experimentalis et applicata 95 (2000), S. 217-227 
    ISSN: 1570-7458
    Keywords: antifeedant ; drimane ; mechanism of action ; sensory response ; toxicity ; habituation ; behavioural observation ; structure-activity relationship ; Pieris brassicae ; Lepidoptera ; Pieridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested 11 analogous synthetic drimane antifeedant compounds for their feeding inhibiting effects on larvae of the large white butterfly Pieris brassicae L. (Lepidoptera: Pieridae) in no-choice tests on the host plant Brassica oleracea L. Furthermore, we observed larval feeding behaviour in no-choice tests to analyze temporal effects of five drimanes. The results show that the five analogous antifeedants differentially influence feeding behaviour and locomotion activity. Warburganal and polygodial are most likely sensory mediated antifeedants. Habituation to these compounds occurs soon after the onset of the tests (i.e., within 0.5–1.5 h). Compound 5 and confertifolin are probably not direct, sensory mediated antifeedants. After 0.5–1.5 h of exposure, these compounds inhibit not only feeding, but also locomotion behaviour, indicating postingestive, toxic effects. Isodrimenin inhibits feeding from the onset of the test and is probably a sensory mediated antifeedant. No habituation occurs to this compound, indicating that isodrimenin is either a very strong antifeedant or that it additionally has postingestive, toxic effects. Topical application of the drimanes on the larval cuticle revealed feeding inhibiting effects, but these could not be related to the occurrence of postingestive feeding inhibiting effects, indicating that this method is inappropriate to show possible postingestive effects of drimanes in P. brassicae. In conclusion, the behavioural observations performed in this research indicate that analogous drimanes inhibit feeding by P. brassicae larvae through multiple mechanisms of action. The results show that, when developing a structure activity relationship (SAR) for a series of antifeedants, it is important to distinguish the mode of action which underlies inhibition of feeding.
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  • 22
    ISSN: 1570-7458
    Keywords: Cnaphalocrocis medinalis ; rice leaffolder ; Lepidoptera ; Pyralidae ; sex pheromone ; geographical variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sex pheromone components of the Japanese rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) were identified from ovipositor extracts of virgin females as (Z)-11-octadecenal, (Z)-13-octadecenal, (Z)-11-octadecen-1-ol and (Z)-13-octadecen-1-ol at a ratio of 11:100:24:36 by GC-EAD, GC, GC-MS. The total amount was estimated to be ca.0.9 ng/female. Field bioassays in Kagoshima, Japan, showed that the two aldehydes are essential for male attraction and the alcohols may have a synergistic effect on the aldehydes. A rubber septum containing 0.9 mg of the four components at the natural ratio was shown to be an effective lure for monitoring this pest in Japan. The above four components are quite different from the sex pheromone components reported previously for the same species of either Philippine or Indian origin; components were shown to be (Z)-11-hexadecenyl acetate and (Z)-13-octadecenyl acetate at a ratio of 98:2 in the Philippine blend and 1:10 in the Indian blend. Furthermore, in the field tests in Japan, neither the Philippine blend nor the Indian blend showed any attractive activity, while the Japanese blend attracted significant numbers of male moths. These results suggest that there are remarkable geographical variations in the sex pheromone composition of this species or there are several distinct species using different sex pheromone blends.
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  • 23
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    Journal of bioenergetics and biomembranes 32 (2000), S. 391-400 
    ISSN: 1573-6881
    Keywords: ATP synthase ; F1-ATPase ; Saccharomyces cerevisiae ; petite mutants ; epistasis ; mitochondrion ; pet mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The mitochondrial ATP synthase is a molecular motor that drives the phosphorylation ofADP to ATP. The yeast mitochondrial ATP synthase is composed of at least 19 differentpeptides, which comprise the F1 catalytic domain, the F0 proton pore, and two stalks, oneof which is thought to act as a stator to link and hold F1 to F0, and the other as a rotor.Genetic studies using yeast Saccharomyces cerevisiae have suggested the hypothesis thatthe yeast mitochondrial ATP synthase can be assembled in the absence of 1, and even 2, ofthe polypeptides that are thought to comprise the rotor. However, the enzyme complexassembled in the absence of the rotor is thought to be uncoupled, allowing protons to freelyflow through F0 into the mitochondrial matrix. Left uncontrolled, this is a lethal process andthe cell must eliminate this leak if it is to survive. In yeast, the cell is thought to lose ordelete its mitochondrial DNA (the petite mutation) thereby eliminating the genes encodingessential components of F0. Recent biochemical studies in yeast, and prior studies in E. coli,have provided support for the assembly of a partial ATP synthase in which the ATP synthaseis no longer coupled to proton translocation.
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  • 24
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    Journal of insect behavior 13 (2000), S. 881-900 
    ISSN: 1572-8889
    Keywords: three-dimensional ; flight track recording ; orientation ; pheromones ; plant volatiles ; image analysis ; real time ; Lobesia botrana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A computer-controlled video system for real-time recording of insect flight in three dimensions is described. The flight paths of moths were recorded in a flight tunnel using two CCD cameras placed adjacent to each other at angles of 45 and 135° to the flight tunnel axis and separated by a distance of 120 cm. They were connected to two 28-level gray-scale frame grabbers via two external synchronizers. The two-dimensional coordinates of the flying insect were obtained from the two cameras at 40-ms intervals and transferred to host computer for processing and monitor for real-time display. Due to speed limitation in the image acquisition hardware, construction of the three-dimensional file was carried off-line. The flying insect was rendered as a dark spot in a bright background using a homogeneous light source. As the insect enters into the field of view of the two cameras, the light distribution changes, and the frame grabber detects only those variation in the light distribution which results from a flying insect. The target insect can be as small as 3 pixels and can be tracked in a stereoscopic field of view 60 cm long and 50 cm high. A method was developed that allowed for scalar scoring of various pheromone sources to assess their attractiveness using vector flight parameters. This method was applied successfully for optimization of pheromone blend of the grapevine moth, Lobesia botrana.
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  • 25
    ISSN: 1572-9699
    Keywords: electron microscopy ; killer effect ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mesophilic wine yeast, Saccharomyces cerevisiae CSIR Y217 K − R − was subjected to the K2 killer effect of Saccharomyces cerevisiae T206 K + R + in a liquid grape medium. The lethal effect of the K2 mycoviral toxin was confirmed by methylene blue staining. Scanning electron microscopy of cells from challenge experiments revealed rippled cell surfaces, accompanied by cracks and pores, while those unaffected by the toxin, as in the control experiments, showed a smooth surface. Transmission electron microscopy revealed that the toxin damaged the cell wall structure and perturbed cytoplasmic membranes to a limited extent.
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  • 26
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    Journal of insect conservation 4 (2000), S. 73-77 
    ISSN: 1572-9753
    Keywords: mapping ; database ; bias recording ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract We use data from the Mersey Valley zone (3×2 km area; N = 600 I ha squares) of the Greater Manchester butterfly atlas to investigate whether recorder visits are biased by access (viz. distance from recorder's home base) and by the locations of potential hot spots. In a multiple regression analysis, visits were found to correlate significantly both with distance from home base of the recorder and with the mean and maximum number of species found in squares. Sites close to the home base of the recorder were visited more frequently than those further afield and squares with more species were visited more frequently than those squares with fewer species. Visits were also made significantly more frequently to squares with greater numbers of butterfly resources (e.g. hostplants, nectar). Furthermore, recording is biased to and away from distinct land uses, which vary significantly in species richness. Reasons are given why these biases are to be expected at all scales. The message is that future distribution mapping should be based on rigorous sampling approaches.
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  • 27
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    Antonie van Leeuwenhoek 78 (2000), S. 187-194 
    ISSN: 1572-9699
    Keywords: cAMP ; pseudohyphae ; Saccharomyces cerevisiae ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Saccharomyces cerevisiae pseudohyphae formation may be triggered by nitrogen deprivation and is stimulated by cAMP. It was observed that even in a medium with an adequate nitrogen supply, cAMP can induce pseudohyphal growth when S. cerevisiae uses ethanol as carbon source. This led us to investigate the effects of the carbon source and of a variety of stresses on yeast morphology. Pseudohyphae formation and invasive growth were observed in a rich medium (YP) with poor carbon sources such as lactate or ethanol. External cAMP was required for the morphogenetic transition in one genetic background, but was dispensable in strain Σ1278b which has been shown to have an overactive Ras2/cAMP pathway. Pseudohyphal growth and invasiveness also took place in YPD plates when the yeast was subjected to different stresses: a mild heat-stress (37 °C), an osmotic stress (1 m NACl), or addition of compounds which affect the lipid bilayer organization of the cell membrane (aliphatic alcohols at 2%) or alter the glucan structure of the cell wall (Congo red). We conclude that pseudohyphal growth is a physiological response not only to starvation but also to a stressful environment; it appears to require the coordinate action of a MAP kinase cascade and a cAMP-dependent pathway.
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  • 28
    ISSN: 1573-4943
    Keywords: Homology modeling ; rotational energy barrier ; simulated annealing ; pyridoxal 5′-diphosphoadenosine ; pyridoxal 5′-triphosphoadenosine ; Saccharomyces cerevisiae ; phosphoenolpyruvate carboxykinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molecular mechanics calculations have been employed to obtain models of the complexes between Saccharomyces cerevisiae phosphoenolpyruvate (PEP) kinase and the ATP analogs pyridoxal 5′-diphosphoadenosine (PLP-AMP) and pyridoxal 5′-triphosphoadenosine (PLP-ADP), using the crystalline coordinates of the ATP-pyruvate-Mn2+-Mg2+ complex of Escherichia coli PEP carboxykinase [Tari et al. (1997), Nature Struct. Biol. 4, 990–994]. In these models, the preferred conformation of the pyridoxyl moiety of PLP-ADP and PLP-AMP was established through rotational barrier and simulated annealing procedures. Distances from the carbonyl-C of each analog to ε-N of active-site lysyl residues were calculated for the most stable enzyme-analog complex conformation, and it was found that the closest ε-N is that from Lys290, thus predicting Schiff base formation between the corresponding carbonyl and amino groups. This prediction was experimentally verified through chemical modification of S. cerevisiae PEP carboxykinase with PLP-ADP and PLP-AMP. The results here described demonstrate the use of molecular modeling procedures when planning chemical modification of enzyme-active sites.
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  • 29
    ISSN: 1573-5028
    Keywords: gene expression ; heterologous expression ; H+/hexose symporter ; Lycopersicon esculentum ; quantitative PCR ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A full-length (LeHT2) and two partial (LeHT1 and LeHT3) cDNA clones, encoding hexose transporters, were isolated from tomato (Lycopersicon esculentum) fruit and flower cDNA libraries. Southern blot analysis confirmed the presence of a gene family of hexose transporters in tomato consisting of at least three members. The full-length cDNA (LeHT2) encodes a protein of 523 amino acids, with a calculated molecular mass of 57.6 kDa. The predicted protein has 12 putative membrane-spanning domains and belongs to the Major Facilitator Superfamily of membrane carriers. The three clones encode polypeptides that are homologous to other plant monosaccharide transporters and contain conserved amino acid motifs characteristic of this superfamily. Expression of the three genes in different organs of tomato was investigated by quantitative PCR. LeHT1 and LeHT3 are expressed predominantly in sink tissues, with both genes showing highest expression in young fruit and root tips. LeHT2 is expressed at relatively high levels in source leaves and certain sink tissues such as flowers. LeHT2 was functionally expressed in a hexose transport-deficient mutant (RE700A) of Saccharomyces cerevisiae. LeHT2-dependent transport of glucose in RE700A exhibited properties consistent with the operation of an energy-coupled transporter and probably a H+/hexose symporter. The K m of the symporter for glucose is 45 μM.
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  • 30
    ISSN: 1573-1561
    Keywords: Insecta ; tobacco hornworm ; Manduca sexta ; tobacco ; Nicotiana tabacum ; ozone ; weather fleck ; Lepidoptera ; Sphingidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tobacco plants, Nicotiana tabacum were grown under different levels of ozone (O3) in open-top chambers. Ozone concentrations were established by charcoal filtration, which reduced O3 to approximately one-half ambient, or by the addition of O3 to unfiltered air to increase concentrations to approximately 1.4 or 1.7 times ambient O3. Survival of tobacco hornworm, Manduca sexta, larvae was increased when second instars were fed tobacco leaves grown in chambers with elevated levels of O3. Second instars also gained significantly more weight when they were fed for one week on plants exposed to elevated levels of O3 than when they were fed plants grown in charcoal-filtered air. Ozone-treated tobacco plants had higher levels of total nitrogen (primarily reduced nitrogen) and soluble carbohydrates (sugars), and lower levels of leaf-surface components, starch, nicotine, and rutin. Increased survival and growth response of hornworm larvae to elevated O3 levels in these experiments suggests that similar responses could occur in the southeastern US tobacco production areas where O3 levels can be high enough to injure tobacco plants.
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  • 31
    ISSN: 1573-1561
    Keywords: Field trapping ; pheromone ; Lepidoptera ; Gelechiidae ; Tuta absoluta ; South American tomato moth ; Scrobipalpuloides absoluta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Field evaluations demonstrate that the addition of the minor pheromone component (3E,8Z)-tetradecadien-1-yl acetate to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate does not significantly increase the trap catches of Tuta absoluta males in the field. The triene acetate itself is highly attractive, catching about 869 ± 255 males per trap in three consecutive nights. The addition of two isomers of the minor component (3E,8Z)-tetradecadien-1-yl acetate, (3E,11Z)-tetradecadienyl-yl acetate and (8Z,11Z)-tetradecadien-1-yl acetate, to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate also did not significantly alter the number of the males caught in the traps.
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  • 32
    ISSN: 1573-1561
    Keywords: Insect pheromones ; pheromone emission ; aggressive chemical mimicry ; predation ; allomone ; Araneae ; Araneidae ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The adult female bolas spider Mastophora hutchinsoni feeds exclusively on attracted males of a few moth species. This exclusivity and the behavior of the approaching moths suggest that the spider aggressively mimics the sex pheromones of its prey species. Males of the bristly cutworm, Lacinipolia renigera, are a major prey of this spider, accounting for about two thirds of the biomass of prey consumed. Female bristly cutworms produce a pheromone blend consisting of (Z)-9-tetradecenyl acetate (Z9–14 : Ac) and (Z,E)-9,12-tetradecenyl acetate (ZE-9,12–14 : Ac). To determine if M. hutchinsoni females mimic the sex pheromone components and blend ratio of L. renigera, we collected volatiles from hunting adult female spiders and analyzed them with gas chromatography–electroantennographic detection (GC-EAD) and gas chromatography–mass spectrometry (GC-MS). GC-EAD analysis of volatile collections, using a male bristly cutworm antenna as the detector and two capillary columns of different polarities, revealed the presence of peaks with retention times (R ts) identical to Z9–14 : Ac and ZE-9,12– 14 : Ac. The mass spectrum of a peak with R t of Z9–14 : Ac was identical to the mass spectrum of the synthetic equivalent. There was an insufficient quantity of the compound with R t of ZE-9,12–14 : Ac to get a full spectrum, but selective detection of ions at m/z 61 and 192 at the correct R t supported the identification. On average, the blend collected from spiders contained 54.8 ± 20.8 (SE) pg/min of Z9–14 : Ac and 2.5 ± 1.7 (SE) pg/min of ZE-9,12–14 : Ac. The latter, on average, comprised 2.6 ± 0.7% of the total, which is similar to the blend ratio emitted by bristly cutworm females. Our results indicate that the adult female M. hutchinsoni produces an allomone blend that mimics not only the composition, but also the blend ratio, of the sex pheromone of a major prey species.
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  • 33
    ISSN: 1573-1561
    Keywords: Female sex pheromones ; Lepidoptera ; Geometridae ; Ennominae ; epoxynonadecene ; epoxynonadecadiene ; chiral epoxide ; chiral HPLC ; dimethyl disulfide adduct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Biston robustum Butler, a polyphagous defoliator, multiplied on Hachijo-jima Island in 1997–1998. Based on GC-MS data of authentic standards, an analysis of a pheromone gland extract of the females indicated that it included (Z,Z)-6,9–nonadecadiene (I), (Z,Z,Z)-3,6,9–nonadecatriene (II), cis-(Z)-6,7–epoxy-9–nonadecene (III), and cis-(Z,Z)-6,7–epoxy-3,9–nonadecadiene (IV) in a ratio of 13 : 2 : 70 : 15. The structure of III was confirmed by a GC-MS analysis of another extract treated with dimethyl disulfide (DMDS). This epoxymonoene was successfully converted into the corresponding DMDS adduct that showed diagnostic ions fragmented at an epoxy ring and at thiomethoxy groups reflecting the position of an original double bond. Furthermore, the 6S,7R configuration was assigned for the epoxy ring of III by chiral HPLC analysis. Field examination of synthetic lures revealed that the two epoxy compounds (III and IV) with the 6S,7R configuration were essential components and that the two unsaturated hydrocarbons (I and II) showed a synergistic effect on male attraction.
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  • 34
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Limacodidae ; Darna trima ; Darna bradleyi ; Setothosea asigna ; Setora nitens ; nettle caterpillars ; oil palm ; sex pheromone ; 2-methylbutyl (E)-7,9-decadienoate ; (E)-2-hexenyl (E)-7,9-decadienoate ; methyl (E)-7,9-decadienoate ; isobutyl (E)-7,9-decadienoate ; (E)-9dodecenal ; (E)-9,11-dodecadienal ; (Z)-9-dodecenal ; (Z)-9,11-dodecadienal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This study was undertaken to identify sex pheromone components of nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera: Limacodidae) whose larvae defoliate oil palm, Elaeis guineensis, in southeast Asia. Coupled gas chromatographic–electroantennographic detection (GCEAD) analyses of pheromone gland extracts revealed two antennally active compounds produced by female D. trima and two by female D. bradleyi. Molecular structures of these candidate pheromone components were identified by electron-impact and chemical-ionization mass spectrometry; retention-index calculations on DB-5, DB-23, and DB-210 columns; microanalytical treatments, as well as syntheses of "auxilliary" compounds that facilitated identification of the compounds. The compounds from D. trima were 2-methylbutyl (E)-7,9-decadienoate (A) and (E)-2-hexenyl (E)-7,9decadienoate (B); from D. bradleyi we identified methyl (E)-7,9-decadienoate (C), and isobutyl (E)-7,9-decadienoate (D). In field experiments in Malaysia, (S)-2-methylbutyl (E)-7,9-decadienoate (SA) in combination with B proved to be essential and synergistic pheromone components for attraction of male D. trima. (R)-2-Methylbutyl (E)-7,9-decadienoate (RA) had no behavioral activity. Compound D singly attracted male D. bradleyi, but addition of C to D at a 1 : 10 ratio significantly enhanced attractiveness of the bait. Synthetic pheromone blends were more effective trap baits than unmated female moths and could be developed for monitoring populations of D. trima and D. bradleyi in Asian oil palm plantations.
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  • 35
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    Journal of chemical ecology 26 (2000), S. 1983-1990 
    ISSN: 1573-1561
    Keywords: Setora nitens ; Setothosea asigna ; nettle caterpillar ; Limacodidae ; Lepidoptera ; sex pheromone ; (Z)-9-dodecenal ; (Z)-9,11-dodecadienal ; (E)-9-dodecenal ; (E)-9,11-dodecadienal ; oil palm ; Elaeis guineensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts of female nettle caterpillars, Setora nitens, revealed four compounds that consistently elicited responses from male moth antennae. Retention indices on three fused silia columns (DB-5, DB-23, and DB-210) of two EAD-active compounds were almost identical to those of (E)-9-dodecenal (E9–12 : Ald) and (E)-9,11-dodecadienal (E9,11–12 : Ald), two pheromone components previously identified in congeneric Setothosea asigna. However, comparative GC, GC-EAD, and GC-mass spectrometry of extracted S. nitens compounds and authentic standards revealed that the candidate pheromone components were (Z)-9-dodecenal (Z9–12 : Ald) and (Z)-9,11-dodecadienal (Z9,11–12 : Ald). The two other EAD-active compounds in pheromone gland extracts proved to be the corresponding alcohols to these aldehydes. In field-trapping experiments in Tawau, Malaysia, synthetic Z9–12 : Ald and Z9,11–12 : Ald at a 1 : 1 ratio, but not singly, attracted male S. nitens. Attractiveness of these two aldehydes could not be enhanced through the addition of their corresponding alcohols. Whether these differences in pheromone biology and chemistry between S. nitens and S. asigna are sufficient to prevent cross-attraction of heterospecific males or whether nonpheromonal mechanisms are required to maintain reproductive isolation is currently being studied.
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  • 36
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    Journal of chemical ecology 26 (2000), S. 2549-2555 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Carposinidae ; (Z)-12–nonadecen-9–one ; chemical identification ; trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The female-produced sex pheromone of the New Zealand raspberry budmoth, Heterocrossa rubophaga, was investigated. Gas chromatographic–mass spectrometric analyses revealed the ketone, (Z)-12–nonadecen9–one (Z12–19–9–one). This compound had previously been found in extracts of the sex pheromone gland of the only other carposine moth for which a sex pheromone has been identified, Carposina niponensis, although its effect on the behavior of C. niponensis males had not been established. Field trapping trials in berry fruit gardens showed this compound to elicit high catches of male H. rubophaga, with the catch appearing to plateau (and perhaps decrease) above a dosage of 300 μg on a red rubber septum. In an analysis of an extract of female H. rubophaga sex pheromone glands, there was a suggestion that the homologous (Z)-7–eicosen-11–one, the known sex pheromone component of C. niponensis, was also present. However this could not be established unequivocally and, in a field trial, addition of a small amount of this compound to Z12–19–9–one resulted in no significant increase in trap catch relative to traps baited with Z12–19–9–one alone.
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  • 37
    ISSN: 1573-1561
    Keywords: Megalophanes viciella ; Psychidae ; Lepidoptera ; bagworm ; sex pheromone ; 1-methylethyl octanoate ; 2-propyl octanoate ; field tests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts obtained by rinsing the thorax and extracts from the tergal sex pheromone gland of females of the bagworm moth, Megalophanes viciella, as well as headspace samples from live animals, were analyzed to reveal the chemical structure of the pheromone. As a result, 1-methylethyl octanoate was established as a main sex pheromone component of this species. This was further confirmed by numerous catches of conspecific males in traps baited with this compound in Bulgaria and Roumania.
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  • 38
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Enarmonia formosana ; cherry bark tortrix ; kairomone ; host selection ; foraging behavior ; plant volatiles ; nonhost volatiles ; repellency/inhibition ; oviposition deterrence ; hexanol ; benzyl alcohol ; nonanal ; decanal ; α-pinene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We tested the hypothesis that males and females of the cherry bark tortrix (CBT), Enarmonia formosana, antennally perceive and behaviorally respond to volatiles from nonhost plants. Volatiles from flowering cherry trees, Prunus serrulata Kwanzan, and from nonhost trees, including trembling aspen, Populus tremuloides, grand fir, Abies grandis, Norway spruce, Picea abies, and Scots pine, Pinus sylvestris, were captured on Porapak Q and extracts analyzed by coupled gas chromatographic–electroantennographic detection (GC-EAD). Compounds that elicited responses from male and female antennae were identified by coupled GC–mass spectrometry (MS) and by comparative GC-MS and GC-EAD with authentic standards. In field cage and field experiments, nonanal from aspen trees and (±)-α-pinene from coniferous trees were effective in reducing captures of male CBT in pheromone-baited traps and deterring oviposition by female CBT on cherry blocks. Recognition of nonhost volatiles, such as nonanal and α-pinene, may allow male and/or female CBT to avoid trees that provide inadequate concealment from predators during calling, resting, and copulation and that are unsuitable for oviposition and development of offspring. Nonhost volatiles may also be exploited for control of CBT by disrupting both mate- and host-finding.
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  • 39
    ISSN: 1573-1561
    Keywords: Scoliopteryx libatrix ; Noctuidae ; Lepidoptera ; sex pheromone ; methylalkene ; (6Z13)-methylheneicosene ; electroantennogram ; field test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The major component of the female-produced sex pheromone of Scoliopteryx libatrix has been characterized by chemical analysis, synthesis, electrophysiological studies and field tests as (6Z,13)-methylheneicosene, probably the 13S-isomer. This is the first example of a branched chain alkene as a sex pheromone in the Noctuidae and is markedly different from the pheromones of other members of the family. The systematic position of S. libatrix, belonging to a monotypic genus of a one-member subfamily within the Noctuidae, may reflect the unusual structure of the sex pheromone.
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  • 40
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    Journal of thermal analysis and calorimetry 59 (2000), S. 643-648 
    ISSN: 1572-8943
    Keywords: drying ; intracellular water ; Saccharomyces cerevisiae ; TG
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The intracellular water content of a microorganism is an important parameter which is a determinant factor of its physiological properties. It is usually measured by complex and time consuming procedures. Thermogravimetry using infrared balance has been used for this purpose, through the identification of different drying steps occurring during the analysis. This work employs the same method with much smaller samples, using conventional thermogravimetric equipment in a simpler and faster way than other conventional procedures. Commercial yeast (Saccharomyces cerevisiae ) washed samples are analyzed in isothermal procedures which are run in about 30 min. The drying rate curve, when plotted as a function of the residual mass of the cells, allows the identification of the step where the intracellular water is lost and the determination of its content. The obtained values, on extracellular water free basis, are in the range of 65 to 69% and agree with those measured by other techniques.
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  • 41
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    Entomologia experimentalis et applicata 97 (2000), S. 339-346 
    ISSN: 1570-7458
    Keywords: crygenes ; PCR ; Lepidoptera ; Spodoptera ; insecticidal activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thirty-five strains of the entomopathogenic bacterium Bacillus thuringiensisactive on Spodoptera exigua, were characterized by means of serological identification and determination of crygene contents by PCR. The insecticidal activity of these 35 strains was further confirmed against S. exiguaand tested against two other species of the same genus: S. littoralisand S. frugiperda. The results indicate that serovars aizawai, thuringiensis, and kurstakiwere the most frequent within S. exigua-active strains and that serovar aizawaihad the highest number of strains exhibiting toxicity against the three species bioassayed. The presence in crygenes as determined by PCR suggests a non random distribution of some crygenes among serovars. Genes cry1C, cry1D, and cry1E, which are known to code for proteins toxic against Spodopteraspecies, were very common within S. exigua-active strains, specially in those belonging to serovar aizawai. However, some strains harbouring one or more of these genes were not toxic to S. littoralisor S. frugiperda; and some strains lacking all of the Spodoptera-active genes were found to be toxic to all three species. This suggests differences in the expression levels among strains bearing toxic genes and the involvement of other genes toxic to Spodopteraspecies. Since strains sharing the same crygenes exhibited different host ranges, the results indicate the need to perform toxicity bioassays in addition to other tests (serological identification and PCR) in order to determine the insecticidal activity of B. thuringiensisstrains.
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  • 42
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    Biodiversity and conservation 9 (2000), S. 479-486 
    ISSN: 1572-9710
    Keywords: biodiversity ; butterfly ; Ghana ; insect ; lagoon ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A variety of collection methods were used to inventory the insect diversity of the Muni-Pomadze Ramsar site along the Ghana coastline. A total of 75 butterfly species in five families were collected and identified. Twenty-six percent of the butterfly species were open country species. The butterflies were all typical of the coastal zone and no endangered or narrowly endemic species were recorded. The Muni-Pomadze site was also rich in other insect species (67 insect species belonging to 15 orders) as a result of the diverse terrestrial habitats surrounding the lagoon. Butterfly species composition changed with habitat indicating a fine-grained response by the butterfly communities to habitat changes. Data from long-term monitoring of butterfly communities at Muni-Pomadze could prove useful as indicators of habitat quality.
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  • 43
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    Chemistry of natural compounds 36 (2000), S. 88-89 
    ISSN: 1573-8388
    Keywords: Saccharomyces cerevisiae ; yeast invertase ; active enzyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The substrate specificity of purified yeast invertase isolated fromSaccharomyces cerevisiae in transglycosylation reactions was determined. The enzyme is specific for primary alcohols. The yeast activity is a function of the alkyl length and substrate hydrophobicity (n-butyl, isobutyl, isoamyl alcohols).
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  • 44
    ISSN: 1432-0762
    Keywords: Key words Copulation duration ; Explosive mating system ; Ejaculate size ; Lepidoptera ; Mating history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The mating system of the Australian lycaenid butterfly, Jalmenus evagoras, is highly unusual compared to most other Lepidoptera. Characteristics of this system, which has been termed an ’explosive mating strategy,’ include the formation of an intensely competitive mating aggregation of males, a highly male biased operational sex ratio, a lack of discrimination and mate choice by both sexes, a high variance in male mating success, and female monogamy. In this study, we tested the hypothesis that multiple mating by males imposes physiological costs resulting in smaller spermatophores, and that this results in a fitness cost to females. We found that male J. evagoras transferred only 2.2% of their eclosion weight during their first mating, consistent with the hypothesis that males of monandrous species produce a relatively small investment. The wet weight of the ejaculate declined by an average of 27% at the second mating and the dry weight by 29%, and an intermating interval of 5–9 days was needed for the ejaculate to return to the size at the first mating, regardless of male size or age. Wet ejaculate mass increased proportionally with male size, though dry mass was proportionally larger in smaller males. Ejaculate mass tended to increase with male age at both first and second matings. Female characteristics, in general, did not affect ejaculate mass, although the wet weight of the ejaculate was positively associated with female weight at the second mating. Copulation duration increased from 2.4 h to approximately 3 h at the second mating, and to over 4 h at the third and fourth matings. Fecundity was positively correlated with female size but not with mating history, copulation duration, or any other characteristics measured for either males or females. Female longevity declined significantly as the number of times the male partner had previously mated increased. We conclude that despite the small male investment in ejaculate, the costs of multiple mating may nonetheless be significant, as indicated by the reduction in ejaculate mass, an increase in copulation duration, and reduction in female lifespan with increasing mating number.
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  • 45
    ISSN: 1432-072X
    Keywords: Key words Plasma membrane H+-ATPase ; PMA1 ; ATPase ; PMA2 ATPase ; Saccharomyces cerevisiae ; Copper stress ; Copper tolerance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major yeast plasma membrane H+-ATPase is encoded by the essential PMA 1 gene. The PMA 2 gene encodes an H+-ATPase that is functionally interchangeable with the one encoded by PMA 1 , but it is expressed at a much lower level than the PMA 1 gene and it is not essential. Using genetically manipulated strains of Saccharomyces cerevisiae that exclusively synthesize PMA1 ATPase or PMA2 ATPase under control of the PMA1 promoter, we found that yeast cultivation under mild copper stress leads to a similar activation of PMA2 and PMA1 isoforms. At high inhibitory copper concentrations (close to the maximum that allowed growth), ATPase activity was reduced from maximal levels; this decrease in activity was less important for PMA2 ATPase than for PMA1 ATPase. The higher tolerance to high copper stress of the artificial strain synthesizing PMA2 ATPase exclusively, as compared to that synthesizing solely PMA1 ATPase, correlated both with the lower sensitivity of PMA2 ATPase to the deleterious effects of copper in vivo and with its higher apparent affinity for MgATP, and suggests that plasma membrane H+-ATPase activity plays a role in yeast tolerance to copper.
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  • 46
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    Current genetics 35 (1999), S. 77-81 
    ISSN: 1432-0983
    Keywords: Key words Adaptive mutations ; 6-N-hydroxylaminopurine ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract The frequency of reversion in a histidine-requiring mutant of Saccharomyces cerevisiae increases about ten-fold in stationary cells during histidine starvation. Histidine starvation enhances a similar frequency of reversion in a tryptophan-requiring mutant. Starvation, therefore, enhances mutation frequencies in a non-adaptive manner. The base analogue 6-N-hydroxylaminopurine (HAP) added prior to plating on medium with limited histidine strongly increases reversion of the histidine mutant. HAP-induced reversion increases further in stationary starving cells with the same kinetics as that which increases spontaneous reversion. Adding HAP to the stationary starving cells does not produce any effect.
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  • 47
    ISSN: 1432-0983
    Keywords: Key words Heteroduplex repair ; Strand discrimina-tion ; Strand interruptions ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract Site-directed mutagenesis was used to construct yeast centromere plasmids in which a strand nick or gap could be placed 5′ or 3′, on either strand, to a reporter gene (SUP4-o) carrying defined base mismatches. The plasmids were then transformed into yeast cells and the direction and efficiency of mismatch repair were assayed by scoring colouring of the transformant colonies. Strands that were nicked were consistently corrected more often than intact strands, but the effect was very small. However, placement of a small gap at the same positions as the nicks resulted in a marked increase in selection for the gapped strand and an enhanced efficiency of mismatch repair. Both the preference for the gapped strand and correction of the mismatch were offset by deletion of the mismatch repair gene PMS1. Together, the results suggest that strand interruptions can direct intracellular mismatch correction of plasmid-borne base mispairs in yeast.
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  • 48
    ISSN: 1432-0983
    Keywords: Key words Cysteine uptake ; Amino-acid permeases ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract Uptake by Saccharomyces cerevisiae of the sulphur-containing amino acid L-cysteine was found to be non-saturable under various conditions, and uptake kinetics suggested the existence of two or more transport systems in addition to the general amino-acid permease, Gap1p. Overexpression studies identified BAP2, BAP3, AGP1 and GNP1 as genes encoding transporters of cysteine. Uptake studies with disruption mutants confirmed this, and identified two additional genes for transporters of cysteine, TAT1 and TAT2, both very homologous to BAP2, BAP3, AGP1 and GNP1. While Gap1p and Agp1p appear to be the main cysteine transporters on the non-repressing nitrogen source proline, Bap2p, Bap3p, Tat1p, Tat2p, Agp1p and Gnp1p are all important for cysteine uptake on ammonium-based medium. Furthermore, whereas Bap2p, Bap3p, Tat1p and Tat2p seem most important under amino acid-rich conditions, Agp1p contributes significantly when only ammonium is present, and Gnp1p only contributes under the latter condition.
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  • 49
    ISSN: 1432-0983
    Keywords: Key words Psoralen sensitivity ; Cytochrome oxidase ; Saccharomyces cerevisiae ; Oxidative stress
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    Topics: Biology
    Notes: Abstract The yeast gene PSO7 was cloned from a genomic library by complementation of the pso7-1 mutant's sensitivity phenotype to 4-nitroquinoline-1-oxide (4NQO). Sequence analysis revealed that PSO7 is allelic to the 1.1-kb ORF of the yeast gene COX11 which is located on chromosome XVI and encodes a protein of 28-kDa localized in the inner mitochondrial membrane. Allelism of PSO7/COX11 was verified by non-complementation of 4NQO-sensitivity in diploids homo- and hetero-allelic for the pso7-1 and cox11::TRP1 mutant alleles. Sensitivity to 4NQO was the same in exponentially growing cells of the pso7-1 mutant and the cox11::TRP1 disruptant. Allelism of COX11 and PSO7 indicates that the pso7 mutant's sensitivity to photoactivated 3-carbethoxypsoralen and to 4NQO is not caused by defective DNA repair, but rather is due to an altered metabolism of the pro-mutagen 4NQO in the absence of cytochrome oxidase (Cox) in pso7-1/cox11::TRP1 mutants/disruptants. Lack of Cox might also lead to a higher reactivity of the active oxygen species produced by photoactivated 3-carbethoxypsoralen. The metabolic state of the cells is important for their sensitivity phenotype since the largest enhancement of sensitivity to 4NQO between wild-type (WT) and the pso7 mutant occurs in exponentially growing cells, while cells in stationary phase or growing cells in phosphate buffer have the same 4NQO resistance, irrespective of their WT/mutant status. Strains containing the pso7-1 or cox11::TRP1 mutant allele were also sensitive to the oxidative stress-generating agents H2O2 and paraquat. Mutant pso7-1, as well as disruptant cox11::TRP1, harboured mitochondria that in comparison to WT contained less than 5% and no detectable Cox activity, respectively.
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  • 50
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    Current genetics 36 (1999), S. 256-261 
    ISSN: 1432-0983
    Keywords: Key wordsFLO8 ; Transcriptional regulation ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is thought that the FLO8 gene encodes a transcriptional activator of the dominant flocculation gene FLO1 in Saccharomycescerevisiae. To determine other genes which are regulated by FLO8, a detailed comparison of the transcripts from the FLO8 and Δflo8 strains was carried out. In addition to the FLO1 gene, it was found that transcription of the FLO11 and STA1 genes is positively regulated by FLO8. In flo8 strains, not only transcripts of the FLO11, STA1, and FLO1 genes but also invasive growth, extracellular glucoamylase production, and flocculation were undetected. From these results, it is suggested that FLO8 regulates these characteristics via the transcriptional regulation of the FLO11, STA1, and FLO1 genes.
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    World journal of microbiology and biotechnology 15 (1999), S. 561-564 
    ISSN: 1573-0972
    Keywords: α-Amylase ; fusion protein ; glucoamylase ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A fusion gene containing the Bacillus subtilis α-amylase gene and Aspergillus awamori glucoamylase cDNA was expressed in Saccharomyces cerevisiae. The resulting bifunctional fusion protein having both α-amylase and glucoamylase activities secreted into the culture medium was purified to apparent homogeneity by affinity chromatography and gel filtration on Sephadex G-100. The enzyme had an apparent molecular mass of 150 kDa and showed an optimum pH and temperature of 6.0 and 60 °C, respectively. The main hydrolysis products from soluble starch were glucose and maltose.
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  • 52
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    World journal of microbiology and biotechnology 15 (1999), S. 629-630 
    ISSN: 1573-0972
    Keywords: Ethanol ; multi-drug resistance ; Saccharomyces cerevisiae ; trichothecin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Trichothecin-resistant mutants were isolated from saké yeast. These mutants were subjected to saké brewing, and showed a higher ethanol productivity than did the parents. They showed multidrug resistance, and resistance to organic compounds. We considered that the higher ethanol productivity of the mutants was related to their resistance to organic compounds and to their ethanol tolerance.
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  • 53
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    Molecular and cellular biochemistry 201 (1999), S. 17-24 
    ISSN: 1573-4919
    Keywords: Saccharomyces cerevisiae ; atomic force microscope ; bioscope ; organic synthesis ; molecular biology ; oxidative stress ; pore enlargement ; cell wall ; baker's yeast ; biotechnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We imaged pores on the surface of the cell wall of three different industrial strains of Saccharomyces cerevisiae using atomic force microscopy. The pores could be enlarged using 10 mM diamide, an SH residue oxidant that attacks surface proteins. We found that two strains showed signs of oxidative damage via changes in density and diameter of the surface pores. We found that the German strain was resistant to diamide induced oxidative damage, even when the concentration of the oxidant was increased to 50 mM. The normal pore size found on the cell walls of American strains had diameters of about 200nm. Under conditions of oxidative stress the diameters changed to 400nm. This method may prove to be a useful rapid screening process (45-60 min) to determine which strains are oxidative resistant, as well as being able to screen for groups of yeast that are sensitive to oxidative stress. This rapid screening tool may have direct applications in molecular biology (transference of the genes to inside of living cells) and biotechnology (biotransformations reactions to produce chiral synthons in organic chemistry.
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  • 54
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    Molecular and cellular biochemistry 202 (1999), S. 109-118 
    ISSN: 1573-4919
    Keywords: NF1 mutations ; IRA1 ; Saccharomyces cerevisiae ; RAS2 ; GAP activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The 2818 amino acids of neurofibromin, the product of the human NF1 gene, include a 230 amino acid Ras-GAP related domain (GRD). Functions which may be associated with the rest of the protein remain unknown. However, many NF1 mutations in neurofibromatosis 1 patients are found downstream of the GRD, suggesting that the C-terminal region of the protein is also functionally important. Since the C-terminal region of neurofibromin encompassing these mutations is homologous with the corresponding regions in the two Saccharomyces cerevisiae Ras-GAPs, Ira1p and Ira2p, we chose yeast as a model system for functional exploration of this region (Ira-C region). Three missense mutations that affect the Ira-C region of NF1 were used as a model for the mutagenesis of IRA1. The yeast phenotypes of heat shock sensitivity, iodine staining, sporulation efficiency, pseudohyphae formation, and GAP activity were scored. Even though none of the mutations directly affected the Ira1p-GRD, mutations at two of the three sites resulted in a decrease in the GAP activity present in ira1 cells. The third mutation appeared to disassociate the phenotypes of sporulation ability and GAP activity. This and other evidence suggest an effector function for Ira1p.
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  • 55
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    Journal of comparative physiology 185 (1999), S. 131-141 
    ISSN: 1432-1351
    Keywords: Key wordsHelicoverpa zea ; Noctuidae ; Lepidoptera ; Sex pheromone ; Antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The limits of a male moth's ability to resolve closely spaced odor filaments have been investigated. Male Helicoverpa zea normally respond to their conspecific sex pheromone blend by exhibiting an upwind flight, which culminates in source contact by at least 50% of the bioassayed individuals. When loaded onto the same filter paper source containing this hitherto attractive pheromone blend, or onto a separate filter paper and co-emitted from the same pipette source with pheromone, (Z)-11-hexadecenyl acetate severely reduced upwind flight and source contact by male H. zea. A similar level of upwind flight inhibition was recorded when the antagonist (Z)-11-hexadecenyl acetate was emitted from its own point source placed 1 mm upwind of the pheromone point source, both plumes being simultaneously emitted in a continuous mode to form a confluent strand. However, (Z)-11-hexadecenyl acetate was less effective in reducing upwind flight and source contact when it was isolated and pulsed from its own source, placed 1 mm either upwind, downwind or cross-wind of a pipette source from which pheromone was simultaneously being pulsed, such that both filaments were separated in time by 0.001–0. 003 s. These results suggest that male H. zea are able to distinguish between odor sources separated by as little as 1 mm in space and 0.001 s in time.
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  • 56
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    Journal of comparative physiology 184 (1999), S. 535-541 
    ISSN: 1432-1351
    Keywords: Key words Insects ; Lepidoptera ; Macroglossum stellatarum ; Colour vision ; Red receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Hymenopterans have long been shown to choose colours by means of the spectral distribution and independently of the intensity (true colour vision). The same ability has only very recently been proven for two butterfly species. We present evidence for the existence of true colour vision in the European hummingbird hawkmoth, Macroglossum stellatarum. Moths were trained in dual-choice situations to spectral lights of a rewarding and an unrewarding wavelength. After training, unrewarded tests were performed during which the intensities of the lights were changed. The results confirm that the species has three spectral receptor types and uses true colour vision when learning the colour of a food source. If colour vision is not possible since only one receptor type is receiving input from both stimuli, the moths learn to associate some achromatic cue correlated to the receptor quantum catch, with the reward. The moths learn spectral cues rapidly and choose correctly after one to several rewarded visits even when trained to different colours in sequence.
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  • 57
    ISSN: 1617-4623
    Keywords: Key words Gene expression ; Glycolysis ; GCR ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Abstract To determine whether similar regulatory mechanisms control the expression of glycolytic genes in yeast and human cells, we screened a human brain cDNA library for clones which complement the growth defect of the gcr2 mutant of Saccharomyces cerevisiae, and isolated hSGT1 (human suppressor of GCR two). Further work confirmed that the rescue of growth was associated with recovery of glycolytic enzyme activities, and that hSGT1 did not complement the growth defect of a gcr1 mutant. A hybrid protein comprising hSgt1p and the DNA-binding domain of Gal4p (GBD) activated a GAL1-lacZ reporter gene fusion, suggesting that the cloned gene may be a transcriptional activator. Two-hybrid experiments in yeast also indicate that hSgt1p interacts with Gcr1p. Northern analysis showed that hSGT1 is highly expressed in muscle and heart. Although the predicted amino acid sequence of hSgt1p does not display significant similarity to Gcr2p, we speculate that their functions may be analogous.
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    Molecular genetics and genomics 260 (1999), S. 551-558 
    ISSN: 1617-4623
    Keywords: Key wordsRAD54 ; Saccharomyces cerevisiae ; Recombination ; Mating-type ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Homothallic Saccharomyces cerevisiae strains switch their mating-type in a specific gene conversion event induced by a DNA double strand break made by the HO endonuclease. The RAD52 group genes control recombinational repair of DNA double strand breaks, and we examined their role in native homothallic mating-type switching. Surprisingly, we found that the Rad54 protein was important but not essential for mating-type switching under natural conditions. As an upper limit, we estimate that 29% of the rad54 spore clones can successfully switch their mating-type. The RAD55 and RAD57 gene products were even less important, but their presence increased the efficiency of the process. In contrast, the RAD51 and RAD52 genes are essential for homothallic mating-type switching. We propose that mating-type switching in RAD54 mutants occurs stochastically with a low probability, possibly reflecting different states of chromosomal structure.
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  • 59
    ISSN: 1617-4623
    Keywords: Key words Cse1p ; Srp1p ; Importin ; Nuclear transport ; Saccharomyces cerevisiae
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    Notes: Abstract The yeast Srp1p protein functions as an import receptor for proteins bearing basic nuclear localization signals. Cse1p, the yeast homolog of mammalian CAS, recycles Srp1p back to the cytoplasm after import substrates have been released into the nucleoplasm. In this report we describe genetic interactions between SRP1 and CSE1. Results from genetic suppression and synthetic lethality studies demonstrate that these gene products interact to ensure accurate chromosome segregation. We also describe new mutant alleles of CSE1 and analyze a new temperature-sensitive allele of CSE1, cse1-2. This allele causes high levels of chromosome missegregation and cell cycle arrest during mitosis at the nonpermissive temperature.
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  • 60
    ISSN: 1617-4623
    Keywords: Key wordsCAT8 ; Transcriptional regulation ; IDP2 ; JEN1 ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The yeast transcriptional activator Cat8p has been identified as a factor that is essential for the derepression of genes involved in gluconeogenesis (like FBP1, PCK1, ACR1, ICL1 and MLS1) when only non-fermentable carbon sources are provided. Cat8p-dependent expression is mediated by cis-acting elements in the respective promoters, which are named UAS/CSREs (upstream activating sequence/carbon source responsive element). To establish whether the function of Cat8p is restricted to the activation of gluconeogenesis or is also involved in the regulation of a greater variety of genes, we investigated the transcriptional regulation of two genes, IDP2 and JEN1, which exhibit a similar expression pattern to gluconeogenic genes, although IDP2 at least is not linked directly to the gluconeogenic pathway. We identified functional UAS/CSRE elements in the promoters of both genes. Expression studies revealed that JEN1 is regulated negatively by the repressors Mig1p and Mig2p, and that Cat8p is needed for full derepression of the gene under non-fermentative growth conditions. Furthermore, we showed that Mig2p is also involved in the repression of CAT8 itself. The results presented in this study support a model in which Cat8p-dependent gene activation is not restricted to gluconeogenesis, but targets a wide variety of genes which are strongly derepressed under non-fermentative growth conditions.
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    Molecular genetics and genomics 262 (1999), S. 589-599 
    ISSN: 1617-4623
    Keywords: Key words Ras/cAMP pathway ; Saccharomyces cerevisiae ; Snf1 ; Mig1 ; Mediator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyclin C and the cyclin C-dependent protein kinase are associated with the RNA polymerase II Mediator complex, which regulates initiation of transcription in response to signals from activators and repressors bound to upstream promoter elements. Disruption of the corresponding genes, SRB11 and SRB10, in budding yeast causes a reduction in expression of the GAL genes, which is particularly pronounced in a mig1 snf1 background. We have screened two yeast genomic libraries for genes that can suppress this phenotype when overexpressed. Seven suppressor genes were identified, GIS1–7. GIS1 encodes one of two related zinc-finger proteins, which also share two other highly conserved domains present in several eukaryotic transcription factors. GIS2 encodes a homologue of the mammalian CNBP and fission yeast Byr3 proteins. GIS3 and GIS4 predict proteins with no obvious similarities to any known proteins. GIS5–7 are identical to the previously described genes PDE2, SGE1 and TUB3, respectively. None of the suppressor genes seem to be involved in Mediator function. Instead, we find that the GIS1, GIS2 and GIS4 genes interact with the CDC25 gene, indicating a possible involvement of these genes in the RAS/cAMP signaling pathway.
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  • 62
    ISSN: 1617-4623
    Keywords: Key wordsKluyveromyces lactis ; Saccharomyces cerevisiae ; GAL1 ; GAL80 ; Protein interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gal1p carries out two functions in the galactose pathway of yeast. It activates Gal4p by interacting with Gal80p – a function that can also served by Gal3p – and it catalyzes the formation of galactose-1-phosphate. Recently, we and others have presented biochemical evidence for complex formation between Gal1p and Gal80p. Here, we extend these data and present genetic evidence for an interaction between Gal1p and Gal80p in vivo, using a two-hybrid assay. Interaction between Gal1p and Gal80p depends on the presence of galactose, but not on the catalytic activity of Gal1p. A new class of Kluyveromyces lactis mutants was isolated, designated Klgal1-m, which have lost the derepressing activity but retain galactokinase activity, indicating that the two Gal1p activities are functionally independent. The KlGal1-m proteins are defective in their ability to interact with Gal80p in a two-hybrid assay. The locations of gal1-m mutations identify putative interaction sites in Gal1p and Gal80p. A dominant mutation, KlGAL1-d, leads to a high level of constitutive expression of genes of the galactose pathway. The behavior of chimeric proteins consisting of Gal3p and KlGal1p sequences indicates that both the N-terminal and C-terminal halves of KlGal1p are involved in specific interaction with KlGal80p.
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  • 63
    ISSN: 1617-4623
    Keywords: Key words Proteasome ; Synthetic lethality ; Saccharomyces cerevisiae ; AAA-ATPase ; 19S Regulatory particle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 19S regulatory particle of the yeast 26S proteasome consists of six related ATPases (Rpt proteins) and at least 11 non-ATPase proteins (Rpn proteins). RPN12 (formerly NIN1) encodes an Rpn component of the 19S regulatory particle and is essential for growth. To determine which subunit(s) of the 26S proteasome interact(s) with Rpn12, we attempted to screen for mutations that cause synthetic lethality in the presence of the rpn12-1 (formerly nin1-1) mutation. Among the candidates recovered was a new allele of RPT1 (formerly CIM5). This mutant allele was designated rpt1-2; on its own this mutation caused no phenotypic change, whereas the rpn12-1 rpt1-2 double mutant was lethal, suggesting a strong interaction between Rpn12 and Rpt1. The site of the rpt1-2 mutation was determined by DNA sequencing of the RPT1 locus retrieved from the mutant, and a single nucleotide alteration was found. This changes amino acid 446 of the RPT1 product from alanine to valine. The alanine residue is conserved in all Rpt proteins, except Rpt5, but no function has yet been assigned to the region that contains it. We propose that this region is necessary for Rpt1 to interact with Rpn12. The terminal phenotype of the rpn12-1 rpt1-2 double mutant was not cell cycle specific, suggesting that in the double mutant cells the function of the 26S proteasome is completely eliminated, thereby inducing multiple defects in cellular functions.
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  • 64
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    Molecular genetics and genomics 262 (1999), S. 332-341 
    ISSN: 1617-4623
    Keywords: Key words Leucine transport ; Saccharomyces cerevisiae ; Trifluoroleucine resistance ; LEP1 ; SAC3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leucine uptake by Saccharomyces cerevisiae is mediated by three transport systems, the general amino acid transport system (GAP), encoded by GAP1, and two group-specific systems (S1 and S2), which also transport isoleucine and valine. A new mutant defective in both group-specific transport activities was isolated by employing a gap1 leu4 strain and selecting for trifluoroleucine-resistant mutants which also showed greatly reduced ability to utilize l-leucine as sole nitrogen source and very low levels of [14C]l-leucine uptake. A multicopy plasmid containing a DNA fragment which complemented the leucine transport defect was isolated by selecting for transformants that grew normally on minimal medium containing leucine as nitrogen source and subsequently assaying [14C]l-leucine uptake. Transformation of one such mutant, lep1, restored sensitivity to trifluoroleucine. The complementing gene, designated LEP1, was subcloned and sequenced. The LEP1 ORF encodes a large protein that lacks characteristics of a transporter or permease (i.e., lacks hydrophobic domains necessary for membrane association). Instead, Lep1p is a very basic protein (pI of 9.2) that contains a putative bipartite signal sequence for targeting to the nucleus, suggesting that it might be a DNA-binding protein. A database search revealed that LEP1 encodes a polypeptide that is identical to Sac3p except for an N-terminal truncation. The original identification of SAC3 was based on the isolation of a mutant allele, sac3-1, that suppresses the temperature-sensitive growth defect of an actin mutant containing the allele act1-1. Sac3p has been previously shown to be localized in the nucleus. When a lep1 mutant was crossed with a sac3 deletion mutant, no complementation was observed, indicating that the two mutations are functionally allelic.
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  • 65
    ISSN: 1617-4623
    Keywords: Key words Oxidative stress signalling ; Mitochondria ; Pos9 (Skn7) ; Ccp1 ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Saccharomyces cerevisiae two transcription factors, Pos9 (Skn7) and Yap1, are involved in the response to oxidative stress. Fusion of the Pos9 response-regulator domain to the Gal4 DNA-binding domain results in a transcription factor which renders the expression of a GAL1-lacZ reporter gene dependent on oxidative stress. To identify genes which are involved in the oxygen-dependent activation of the Gal4-Pos9 hybrid protein we screened for mutants that failed to induce the heterologous test system upon oxidative stress (fap mutants for factors activating Pos9). We isolated several respiration-deficient and some respiration-competent mutants by this means. We selected for further characterization only those mutants which also displayed an oxidative-stress-sensitive phenotype. One of the respiration-deficient mutants (complementation group fap6) could be complemented by the ISM1 gene, which encodes mitochondrial isoleucyl tRNA synthetase, suggesting that respiration competence was important for signalling of oxidative stress. In accordance with this notion a rho0 strain and a wild-type strain in which respiration had been blocked (by treatment with antimycin A or with cyanide) also failed to activate Gal4-Pos9 upon imposition of oxidative stress. Another mutant, fap24, which was respiration-competent, could be complemented by CCP1, which encodes the mitochondrial cytochrome c peroxidase. Mitochondrial cytochrome c peroxidase degrades reactive oxygen species within the mitochondria. This suggested a possible sensor function for the enzyme in the oxidative stress response. To test this we used the previously described point mutant ccp1 W191F , which is characterized by a 104-fold decrease in electron flux between cytochrome c and cytochrome c peroxidase. The Ccp1W191F mutant was still capable of activating the Pos9 transcriptional activation domain, suggesting that the signalling function of Ccp1 is independent of electron flux rates.
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  • 66
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    Oecologia 119 (1999), S. 565-571 
    ISSN: 1432-1939
    Keywords: Key wordsVespula ; Lepidoptera ; Phenology ; Shared predator ; Ecological impact
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Introduced social wasps (Vespula vulgaris) reach high densities in some New Zealand beech forests, because honeydew provides an abundant high-energy food source. We manipulated wasp density to estimate an “ecological damage threshold” for large, free-living Lepidoptera larvae. There will be a continuum of ecological damage thresholds for wasp density depending on the prey species or habitat. Experimentally placed small caterpillars had a significantly higher survival rate than large caterpillars, and the survival rate of both groups decreased with increasing wasp density. Spring-occurring caterpillars have a probability of surviving of 0.90–0.95, assuming wasps are the only source of mortality. However, at the peak of the wasp season we predict caterpillars would have virtually no chance (probability of 10−78 to 10−40) of surviving to adults. Wasp abundance must be reduced by at least 88% to conserve the more vulnerable species of free-living caterpillars at wasp densities similar to those observed in our study sites. This equates to a damage threshold of 2.7 wasps per Malaise trap per day. It was exceeded for about 5 months of the year in non-poisoned sites. There are currently no biological or chemical control techniques available in New Zealand that will reduce wasp abundance below this damage threshold throughout the year. Our models show that most Lepidoptera with spring caterpillars will be able to persist, but species with caterpillars occurring in the peak wasp season will be eliminated.
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  • 67
    ISSN: 1572-8773
    Keywords: iron ; siderophores ; transport ; Saccharomyces cerevisiae ; fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Transport proteins of microorganisms may either belong to the ATP-binding cassette (ABC) superfamily or to the major facilitator (MFS)-superfamily. MFS transporters are single-polypeptide membrane transporters that transport small molecules via uniport, symport or antiport mechanisms in response to a chemiosmotic gradient. Although Saccharomyces cerevisiae is a non-siderophore producer, various bacterial and fungal siderophores can be utilized as an iron source. From yeast genome sequencing data six genes of the unknown major facilitator (UMF) family were known of which YEL065w Sce was recently identified as a transporter for the bacterial siderophore ferrioxamine B (Sit1p). The present investigation shows that another UMF gene, YHL047c Sce, encodes a transporter for the fungal siderophore triacetylfusarinine C. The gene YHL047c Sce (designated TAF1) was disrupted using the kanMX disruption module in a fet3 background (strain DEY 1394 Δfet3), possessing a defect in the high affinity ferrous iron transport. Growth promotion assays and transport experiments with 55Fe-labelled triacetylfusarinine C showed a complete loss of iron utilization and uptake in the disrupted strain, indicating that TAF1 is the gene for the fungal triacetylfusarinine transport in Saccharomyces cerevisiae and possibly in other siderophore producing fungi.
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  • 68
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    Entomologia experimentalis et applicata 93 (1999), S. 179-187 
    ISSN: 1570-7458
    Keywords: artificial diet ; insecticidal activity ; legume pod borer ; Lepidoptera ; Maruca vitrata ; plant lectins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The legume pod-borer Maruca vitrata (Fabricius), [Lepidoptera: Pyralidae] is a major constraint restricting increased cowpea production in tropical Africa and Asia. Since lectins are known to have insecticidal properties against several pests, a survey was undertaken to screen for the effects of 25 lectins from 15 plant families on the development of Maruca pod borer (MPB) larvae. The list included 8 galactose/N-acetylgalactosamine-, 7 mannose-, 5 complex glycan-, 2 sialic acid- and 3, N-acetylglucosamine-specific lectins. Feeding bioassays using artificial diet were carried out at 2% (w/w) topical levels. Although a total of 16 lectins had detrimental effects pertaining either to larval survival, weight, feeding inhibition, pupation, adult emergence and/or fecundity, only the Listera ovata agglutinin (LOA) (Orchidaceae) and Galanthus nivalis (Amaryllidaceae) agglutinin were effective against MPB larvae for all six parameters examined. Larval mortality and feeding inhibition caused by the most active lectin (LOA) was above 60%.
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  • 69
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    Entomologia experimentalis et applicata 90 (1999), S. 37-47 
    ISSN: 1570-7458
    Keywords: Choristoneura rosaceana ; obliquebanded leafroller ; Lepidoptera ; Tortricidae ; mating disruption ; mechanisms ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An attractive four-component pheromone blend containing a major component Z11-tetradecenyl acetate, and three minor components, E11-tetradecenyl acetate, Z11-tetradecenyl alcohol, and Z11-tetradecenyl aldehyde was tested as a mating disruptant against western Canadian populations of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), in organic apple orchards in British Columbia. Efficacy of this four-component blend was compared to that of partial pheromone blends containing the major component plus one or two minor components. A trapping experiment confirmed that, Conrel® fibre disruption dispensers containing the four-component blend were more attractive than disruption dispensers containing the two- or three-component partial blends. A small-plot protocol was followed to compare atmospheric treatments with these blends as mating disruptants at a release rate of 10 mg ha−1 h−1 and from 1000 dispensers ha−1. Mechanisms of mating disruption, such as false-trail following and camouflage of pheromone plumes, that may be evoked to a greater degree by an attractive blend, did not appear to augment the effectiveness of mechanisms invoked by the less attractive blends, as the proportion of mating among tethered females was equal in plots treated with these blends and was reduced by 85–90% compared to the nontreated control. When the four-component pheromone blend was tested at different release rates, mating disruption in small plots began to break down at a release rate of 1.3 mg ha−1 h−1 using a dispenser density of 1000 ha−1. Above 1.3 mg ha−1 h−1 there was no dose response in release rates tested and at release rates below this dose the proportion of tethered females mating was the same as in the nontreated control. The four-component pheromone blend was tested against, and found to be no more effective than, the two-component partial blend at the threshold release rate of 1.3 mg ha−1 h−1 when it was released from 1000 or 250 disruption dispensers. Our results suggest that disruption mechanisms evoked by the attractive blend did not enhance the mating disruption effect provided by the simple blend, therefore a two-component blend may be useful in an operational mating disruption program for C. rosaceana.
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  • 70
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    Entomologia experimentalis et applicata 90 (1999), S. 131-140 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; avocadofurans ; Spodoptera exigua ; avocado ; idioblast ; oil cell ; food preference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the effect of two avocadofurans, 2-(pentadecyl)furan and 2-(heptadecyl)furan, from avocado idioblast oil cells on maturation and larval feeding behavior of a generalist insect herbivore, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Experiments were conducted using two larval sizes: early-stadium larvae refer to those larvae from experiments initiated with neonates while late-stadium larvae refer to those larvae from experiments initiated with third instars. In order to use selected sublethal doses for developmental and behavioral studies on early- and late-stadium larvae, log-dose probit lines were determined using diet incorporation bioassays. Both avocadofurans had similar toxicities to early-stadium larvae [LC50=2.2 and 1.9 μmoles/g of diet for 2-(pentadecyl)furan and 2-(heptadecyl)furan, respectively] and late-stadium larvae (LC50=3.0 and 3.4 μmoles/g of diet, respectively). In diet bioassays extending from egg hatch to adult emergence, the avocadofurans significantly prolonged larval developmental times and reduced S. exigua pupal weights. In 7 d no-choice bioassays initiated with cohorts of newly-molted third instars, the avocadofurans significantly reduced larval weights at various sublethal concentrations (below LC50 values). To test larval feeding deterrence effects of these avocadofurans, choice tests were conducted using early and older instar larvae. A significantly higher proportion of early-stadium larvae preferred control diet over diet treated with either avocadofuran at several sublethal concentrations. Similarly, choice tests with late-stadium larvae showed greater proportions of larvae on control diet than treated diet even at concentrations below the LC50. Moreover, late-stadium larvae consumed significantly more of the control diet than the treated diet. Thus, the avocadofurans may act as feeding deterrents as well as toxicants in plant protection against non-adapted insect herbivores.
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  • 71
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    Entomologia experimentalis et applicata 91 (1999), S. 237-244 
    ISSN: 1570-7458
    Keywords: host plant range ; sex pheromone ; Ostrinia furnacalis ; Ostrinia latipennis ; Ostrinia nubilalis ; Ostrinia orientalis ; Ostrinia palustralis ; Ostrinia scapulalis ; Ostrinia zaguliaevi ; Ostrinia zealis ; Lepidoptera ; Pyralidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To contribute to the understanding of the genus Ostrinia (Lepidoptera; Pyralidae) in Japan, we collected larvae of Ostrinia spp. from known host plants and plants not recorded as hosts, and we examined the morphology and sex pheromones of the adults obtained. Consequently, the host plant ranges of the 7 Ostrinia spp. in Japan were clarified, and the sex pheromones of the 5 species O. scapulalis, O. zealis, O. zaguliaevi, O. palustralis and O. latipennis were identified in addition to that of the Asian corn borer O. furnacalis. The phylogenetic relationships of Japanese Ostrinia spp., with reference to the European corn borer O. nubilalis, are discussed based on these findings and results of molecular phylogenetic analyses.
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  • 72
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Plodia interpunctella ; Indian meal moth ; pheromone components ; GC-EAD ; stored-product pest ; behaviour ; flight tunnel ; trapping ; Ephestia kuehniella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:OAc), (Z,E)-9,12-tetradecadienal (Z9,E12-14:Ald) and (Z,E)-9,12-tetradecadienol (Z9,E12-14:OH). A fourth EAD-active compound was identified as (Z)-9-tetradecenyl acetate (Z9-14:OAc). The homologue (Z)-11-hexadecenyl acetate (Z11-16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD-active compounds and the responses to female gland extacts. A behavioural assay of different two-compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12-14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four-compound blend reduced its activity significantly. We thus conclude that the female-produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12-14:OAc, Z9,E12-14:Ald, Z9,E12-14:OH and Z9-14:OAc. In a field trapping test performed in a storage facility, the four-component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12-14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.
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  • 73
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    Entomologia experimentalis et applicata 91 (1999), S. 59-65 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Mamestra brassicae ; host-finding behaviour ; visual cues ; host-choice ; interaction ; odour ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The approach and landing responses of female Mamestra brassicae (L.) (Lepidoptera: Noctuidae) to visual cues from artificial plant leaves of different shapes and presence/absence of cabbage plant odour were investigated in a laboratory wind tunnel. The leaves were painted with cadmium yellow colour and observed under dim red light. Females showed oriented flight towards plant odours but landed significantly more often when the odour was presented with an artificial leaf. In three-choice tests, the shape of the leaf targets (circle, square or triangle) did not influence the female response. However, the size of the target did influence the insect response: the females preferred landing on square targets with sides of 5 or 10 cm rather than on the largest target, with sides of 15 cm. The orientation of the target influenced the insects' response: females landed significantly more often on the target positioned vertically than horizontally.
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  • 74
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    Journal of bioenergetics and biomembranes 31 (1999), S. 95-104 
    ISSN: 1573-6881
    Keywords: F1-ATPase ; β-barrel domain ; mitochondria ; assembly ; yeast ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The crystal structure of mitochondrial F1-ATPase indicatesthat the α and β subunits fold into a structure defined by threedomains: the top β-barrel domain, the middle nucleotide-binding domain,and the C-terminal α-helix bundle domain (Abraham et al.1994); Bianchet et al., 1998). The β-barrel domains of theα and β subunits form a crown structure at the top ofF1, which was suggested to stabilize it (Abraham et al.1994). In this study. the role of the β-barrel domain in the α andβ subunits of the yeast Saccharomyces cerevisiae F1,with regard to its folding and assembly, was investigated. The β-barreldomains of yeast F1 α and β subunits were expressedindividually and together in Escherichia coli. When expressedseperately, the β-barrel domain of the β subunit formed a largeaggregate structure, while the domain of the α subunit waspredominately a monomer or dimer. However, coexpression of the β-barreldomain of α subunit domain. Furthermore, the two domains copurified incomplexes with the major portion of the complex found in a small molecularweight form. These results indicate that the β-barrel domain of theα and β subunits interact specifically with each other and thatthese interactions prevent the aggregation of the β-barrel domain of theβ subunit. These results mimic in vivo results and suggest thatthe interactions of the β-barrel domains may be critical during thefolding and assembly of F1.
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  • 75
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    Journal of insect behavior 12 (1999), S. 199-211 
    ISSN: 1572-8889
    Keywords: Lepidoptera ; Tortricidae ; Lobesia botrana ; flight activity ; wind tunnel ; atmospheric pressure ; flight experience ; mating ; age ; olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied modulations of flight activity in European grapevine moth females (EGVM) by individual observations in a wind tunnel. The effect of different factors was analyzed: variation in atmospheric pressure prior to the experiments, time of day, first experience of flight, age, mating, and odor of tansy, which attracts females. The circadian flight activity showed a peak the hour preceding the onset of scotophase and sustained activity occurred during the 6 h around this peak. Females with a flight experience in the tunnel took off more quickly than naive ones (3.9 ± 7.4 vs 20.3 ± 22.8 s). Three-day-old unmated females subjected to negative variations of atmospheric pressure (10 hPa) during the 4 h prior to the experiments increased their duration of flight (12.1 ± 8.7 vs 5.3 ± 3.4 s) compared to those not subjected to variation. One-day-old females were less active than older ones; flight was shorter than in 2-day-old females (2.7 ± 6.7 vs 5.1 ± 9.5 s) and fewer of them took off (28 vs 63%). Mating also affected the flight activity of 2-day-old females; mated females flew longer than virgins (12 ± 16.8 vs 5.1 ± 9.5 s) and took off more quickly (6.5 ± 14.4 vs 19.3 ± 20.1 s). Tansy odor in the tunnel did not significantly affect the flight behavior of virgin females, but it increased the proportion of mated females that initiated flight (87 vs 70%) and duration of flight (11.2 ± 24.4 vs 7.2 ± 13.7 s), and it reduced the latency to takeoff (2.1 ± 7.4 vs 8.1 ± 19.1 s). Flight duration in tansy odor was inversely correlated with the total number of eggs laid during the female's whole life. Our experimental settings did not allow observation of movements directed toward the odor source.
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    Journal of insect conservation 3 (1999), S. 15-24 
    ISSN: 1572-9753
    Keywords: census ; conservation ; Lepidoptera ; population monitoring ; survey techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract The use of light traps in sampling moth populations is an established technique used by entomologists and ecologists. However, trap data partly reflect the variable attractiveness of UV light to different species of moth. There are also potential problems of the practicality and expense of running traps in certain locations. An alternative method of recording moth populations is developed, using a modification of the transect count technique used for butterflies (Pollard and Yates, 1993) and recently applied to moths (Spalding, 1997). During transects, moths were observed by torch-light in a 5 by 5 m box, before the recorder walked on for 10 paces, and recorded moths in the next 5 m box. The transect approach was tested in the field, alongside traditional light trap and sugar methods. Transects recorded moth species for relatively little effort, produced repeatable measures of relative density, and provided habitat-specific data. This approach is likely to provide a valuable addition to light trapping in biodiversity inventories, species surveys, and in monitoring the effects of habitat management for conservation.
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    Journal of insect conservation 3 (1999), S. 33-42 
    ISSN: 1572-9753
    Keywords: mapping ; database ; bias recording ; monitoring ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract Data from the Greater Manchester Butterfly Atlas (UK) reveal a highly significant and substantial impact of visits on both species' richness and species' incidence in squares. This effect has been demonstrated for three different zones mapped at different scales. The significant impact of number of visits persists when data are amalgamated for coarser scales. The findings demonstrate that it is essential for distribution mapping projects to record data on recording effort as well as on the target organisms. Suggestions are made as to how distribution mapping may be improved, including a geographically and environmentally representative structure of permanently monitored squares and closer links between distribution mapping and the Butterfly Monitoring Scheme (BMS), which primarily monitors changes in butterfly populations. The benefit to conservation will be data that can be better used to analyse the reasons for changes in ranges and distributions, fundamental for determining priorities and policy decisions.
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  • 78
    ISSN: 1573-4943
    Keywords: Phosphoenolpyruvate carboxykinase ; oxaloacetate decarboxylase ; pyruvate kinase-like activity ; Anaerobiospirillum succiniciproducens ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two members of the ATP-dependent class of phosphoenolpyruvate carboxykinases (PEPCKs) (Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens) have been comparatively studied with regard to their oxaloacetate (OAA) decarboxylase and pyruvate kinase-like activities. The pyruvate kinase-like activities were dependent on the presence of Mn2+; at the same concentrations Mg2+ was not effective. These activities were synergistically activated by a combination of both metal ions. V max for these activities in A. succiniciproducens and S. cerevisiae PEPCKs was 0.13% and 1.2% that of the principal reaction, respectively. The OAA decarboxylase activity was nucleotide independent and, with decreasing order of effectiveness, these activities were supported by Mn2+ and Mg2+. AMP is an activator of these reactions. V max for the OAA decarboxylase activities in A. succiniciproducens and S. cerevisiae PEPCKs was 4% and 0.2% that of the PEP-forming reaction, respectively.
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    Plant molecular biology 39 (1999), S. 117-128 
    ISSN: 1573-5028
    Keywords: LEA protein ; osmotic stress ; Saccharomyces cerevisiae ; drought ; salt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biased amino acid composition and aperiodic (random coil) configuration of Group 1 late embryogenesis-abundant (LEA) proteins imply that these proteins are capable of binding large amounts of water. While Group 1 LEAs have been predicted to contribute to osmotic stress protection in both embryonic and vegetative tissues, biochemical support has been lacking. We have used Saccharomyces cerevisiae as a model system to test the putative osmoprotective function of a wheat Group 1 LEA protein, Em. We demonstrate that expression of Em protein in yeast cells is not deleterious to growth in media of normal osmolarity and attenuates the growth inhibition normally observed in media of high osmolarity. Enhanced growth is observed in the presence of a variety of osmotically active compounds indicating that Em protein is capable of mitigating the detrimental effect of low water potential in a relatively non-specific manner. These results are the first biochemical demonstration of an osmoprotective function for a Group 1 LEA and suggest that the yeast expression system will be useful in dissecting the mechanism of protection through structure-function studies.
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  • 80
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; heterologous expression ; isoprenoids ; mevalonate diphosphate decarboxylase ; sterols ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sequence comparison with the mevalonate diphosphate decarboxylase (MVD) amino acid sequence of Saccharomyces cerevisiae identified an EST clone corresponding to a cDNA that may encode Arabidopsis thaliana MVD (AtMVD1). This enzyme catalyses the synthesis of isopentenyl diphosphate, the building block of sterol and isoprenoid biosynthesis, and uses mevalonate diphosphate as a substrate. Sequencing of the full-length cDNA was performed. The predicted amino acid sequence presents about 55% identity with the yeast, human and rat MVDs. The sequence of the genomic region of A. thaliana MVD was also obtained and Southern blot analysis on genomic DNA showed that A. thaliana could have at least one homologous MVD gene. In order to allow heterologous expression in S. cerevisiae, the MVD open reading frame (ORF) was then cloned under the control of the yeast PMA1 strong promoter. When expressed in yeast, the A. thaliana cDNA complemented both the thermosensitive MN19-34 strain deficient in MVD, and the lethal phenotype of an ERG19 deleted strain. However, the wild-type sterol content was not fully restored suggesting that the A. thaliana MVD activity may not be optimal in yeast. A two-hybrid assay was also performed to evaluate homodimer formation of the A. thaliana MVD and heterodimer formation between the plant and yeast heterologous enzymes.
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  • 81
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    Journal of chemical ecology 25 (1999), S. 2535-2545 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; Lymantria xylina ; Lymantria dispar ; Lymantria monacha ; Lymantria fumida ; sex pheromone ; reproductive isolation ; (7R,8S)-cis-7,8-epoxy-2-methyleicosane ; (7S,8R)-cis-7,8-epoxy-2-methyleicosane ; 2-methyl-Z7-eicosene ; (7R,8S)-cis-7,8-epoxy-2-methylnonadecane ; (7S,8R)-cis-7,8-epoxy-2-methylnonadecane ; (7R,8S)-cis-7,8-epoxy-3-methylnonadecane ; (7S,8R)-cis-7,8-epoxy-3-methylnonadecane ; disparlure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract cis-7,8-Epoxy-2-methyleicosane is a sex pheromone component of the Casuarina moth, Lymantria xylina Swinhoe. The compound was extracted from pheromone glands of female moths and was identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) and GC–mass spectrometry. In field experiments in Taiwan, traps baited with either or both of (7R,8S)-cis-7,8-epoxy-2-methyleicosane (〉99% ee) [termed here (+)-xylinalure] and (7S,8R)-cis-7,8-epoxy-2-methyleicosane (〉99% ee) [termed here (−)-xylinalure] captured male L. xylina. Addition of further candidate pheromone components to xylinalure did not enhance its attractiveness. Demonstration of whether or not female L. xylina produce both optical isomers of xylinalure, and determination of the ratio, will require pheromone extract analyses on a chiral, enantiomer-separating column (as yet unavailable) or derivatization of epoxides in accumulated gland extracts. Attraction of male L. xylina to either enantiomer of xylinalure contrasts with enantiospecific production of, and/or response to, epoxy pheromones in congeners. With no other nocturnal lymantriid moth known in Taiwan to utilize xylinalure for pheromonal communication, enantiospecific “fine tuning” of xylinalure, or evolution of a more complex pheromone blend, may not have been necessary for L. xylina to maintain specificity of sexual communication. Racemic xylinalure will be appropriate for pheromone-based detection surveys of L. xylina in North America.
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  • 82
    ISSN: 1573-1561
    Keywords: Coniesta ignefusalis ; Acigona ignefusalis ; Lepidoptera ; Pyralidae ; sex pheromone ; (Z)-7-dodecen-1-ol ; (Z)-5-decen-1-ol ; (Z)-7-dodecenal ; (Z)-7-dodecenyl acetate ; (Z)-9-tetradecen-1-ol
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Five active compounds were detected during analyses of ovipositor washings and effluvia from virgin female Coniesta ignefusalis moths by gas chromatography (GC) linked to electroantennographic (EAG) recording from a male moth. These were identified as (Z)-7-dodecen-1-ol (Z7–12:OH), (Z)-5-decen-1-ol (Z5–10:OH), (Z)-7-dodecenal (Z7–12:Ald), (Z)-7-dodecenyl acetate (Z7–12:Ac), and (Z)-9-tetradecen-1-ol (Z9–14:OH) by comparison of their GC retention times, mass spectra, and EAG activities with those of synthetic standards. Laboratory tests of dispensers for these compounds showed that release rates from polyethylene vials increased to relatively uniform values after three to four days, but release from septa was very rapid and nonuniform and decreased to low levels after two to three days. Trapping tests in Niger showed that the major component, Z7–12:OH, and two of the minor components, Z5–10:OH and Z7–12:Ald, were essential for attraction of male C. ignefusalis moths. The most attractive blend contained these three components in a 100:5:3.3 ratio in a polyethylene vial, which emitted the components in similar proportions to those produced by the female C. ignefusalis moth. Water traps baited with this blend containing 1 mg of Z7–12:OH caught more male C. ignefusalis moths than traps baited with newly emerged female moths. Addition of up to 10% of the corresponding E isomers of the pheromone components had no effect on catches, but addition of the other two minor components detected, Z7–12:Ac and/or Z9–14:OH, to the attractive blend at naturally occurring levels caused significant reductions in trap catch.
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  • 83
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; white-spotted tussock moth ; Orgyia thyellina ; (Z)-6-heneicosen-11-one ; (Z)-6-heneicosen-9-one ; (Z)-6,(E)-8-heneicosadien-11-one ; sex pheromone ; synergism ; quarantine insect ; international trade ; eradication ; Bacillus thuringiensis ; microbial insecticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic–electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6–11-one) and (Z)-6-heneicosen-9-one, the latter termed here “thyellinone.” In field experiments in Japan, Z6–11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997–1998 summer, 45,000 commercial trap lures baited with 2000 μg of Z6–11-one and 100 μg of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.
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  • 84
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    Journal of chemical ecology 25 (1999), S. 1343-1351 
    ISSN: 1573-1561
    Keywords: Host-plant volatiles ; apple ; Malus domestica ; reproductive behavior ; codling moth ; Cydia pomonella ; Tortricidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Apple volatiles stimulated pheromone release, oviposition, and upwind orientation in female codling moths, Cydia pomonella. Green apples increased the percentage of virgin females calling, the duration of female calling, and advanced the onset of egg-laying in gravid females. In a tube olfactometer, both virgin and mated females were more active in the presence of apple volatiles than in clean air. They responded by walking while wing-fanning; mated females showed a stronger attraction response than unmated females.
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  • 85
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    Journal of chemical ecology 25 (1999), S. 2305-2312 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; Lymantria fumida ; Lymantria monacha ; nun moth ; sex pheromone ; periodicity ; calling behavior ; reproductive isolation ; disparlure ; (7R,8S)-cis-7,8-epoxy-2-methyloctadecane ; (7S,8R)-cis-7,8-epoxy-2-methyloctadecane ; 2-methyl-Z7-octadecene ; (7R,8S)-cis-7,8-epoxy-octadecane ; (+)-monachalure
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts of pheromone glands from female Lymantria fumida were analyzed by coupled gas chromatographic–electroantennographic detection (GC-EAD) and by coupled GC–mass spectrometry (MS). The two compounds that elicited responses from male L. fumida antennae were identified as cis-7,8-epoxy-2-methyloctadecane (disparlure) and 2-methyl-Z7-octadecene (2me-Z7–18Hy). Field experiments in northern Japan demonstrated that synthetic (7R,8S)-cis-7,8-epoxy-2-methyloctadecane [(+)-disparlure] and 2me-Z7–18Hy are synergistic sex pheromone components of L. fumida. (7S,8R)-cis-7,8-Epoxy-2-methyloctadecane [(−)-disparlure] had no behavioral effect on male L. fumida. Traps baited with (+)-disparlure and 2me-Z7–18Hy captured male L. fumida between 21:00 and 24:00 hr, whereas traps baited with (+)-monachalure [(7R,8S)-cis-7,8-epoxy-octadecane], (+)-disparlure and 2me-Z7–18Hy attracted males of the nun moth, L. monacha L., between 02:00 and 04:00 hr. Both temporal separation of pheromonal communication and specificity of pheromone blends seem to contribute to the reproductive isolation of sympatric and coseasonal L. fumida and L. monacha.
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  • 86
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    Journal of chemical ecology 25 (1999), S. 1233-1245 
    ISSN: 1573-1561
    Keywords: Swallowtail butterfly ; Papilionidae ; Papilio troilus ; Lepidoptera ; Lauraceae ; Sassafras albidum ; oviposition stimulant ; 3-trans-caffeoyl-muco-quinic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Female butterflies of the spicebush swallowtail, Papilio troilus, are specialists, ovipositing on plants in the family Lauraceae. Column chromatography and HPLC were used to isolate an oviposition stimulant from the leaves of one of its hosts, Sassafras albidum. The stimulant was identified as 3-trans-caffeoyl-muco-quinic acid on the basis of FAB-MS and 1H NMR spectra as compared to a compound previously isolated from another plant. It was not active alone, but it increased the oviposition activity of butterflies when combined with other stimulant(s) at a concentration of 7 ng/mm2 leaf surface area. Other caffeoylquinic acid isomers tested did not have this effect. This is the first report of a swallowtail contact oviposition stimulant from a plant in the family Lauraceae.
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  • 87
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    Journal of chemical ecology 25 (1999), S. 1945-1960 
    ISSN: 1573-1561
    Keywords: Insect–plant interaction ; midgut alkalinization ; phylogenetic distribution ; Mecopterida ; Diptera ; Lepidoptera ; Trichoptera ; polyphenolics ; alkylating agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The phylogenetic distribution of reported midgut pH values among larval Mecopterida supports a model in which the common ancestor of this group possessed an alkaline midgut, with subsequent loss of this trait in the lineage leading to the muscomorphan Diptera. The relationship between midgut pH and diet guild rank within the Lepidoptera and Diptera was tested by assigning numerical values to diet guilds (i.e., fruit, grasses, herbs, trees and shrubs, and organic detritus). Lepidopteran superfamilies were found to differ significantly in both midgut pH and in diet guild rank. Regression of mean superfamily midgut pH against mean superfamily diet guild rank yielded an R 2 of 0.79 (N = 10), whereas regression of species midgut pH against species diet guild rank yielded an R 2 of only 0.15 (N = 60). Species feeding on foliage of plant taxa high in tannins and on Solanaceae have midgut pH values above 9, and midgut pH in species feeding on these taxa is positively related to diet guild. In contrast, species feeding on the foliage of plant taxa containing terpenes, DIMBOA, glucosinolates, and pyrrolizidine alkaloids have midgut pH values near 8, and midgut pH of these species is either not related to diet guild (all species) or is negatively related to diet guild rank when the analysis is limited to the Noctuoidea. The data suggest that decreased midgut pH in species feeding on plants containing terpenes, DIMBOA, glucosinolates, and pyrrolizidine alkaloids may be an adaptive response that overrides selection for high pH in the presence of tannins and that midgut pH may be one factor contributing to the limitation of the host plant range of many species of lepidopteran herbivores.
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  • 88
    ISSN: 1573-1561
    Keywords: Tritrophic interactions ; Lima bean ; Phytoseiulus persimilis ; Tetranychus urticae ; Spodoptera exigua ; Acari ; Lepidoptera ; infochemicals ; herbivore-induced plant volatiles ; nonprey herbivores ; feces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effect of volatiles related to feeding activity of nonprey caterpillars, Spodoptera exigua, on the olfactory response of the predatory mites Phytoseiulus persimilis was examined in a Y-tube olfactometer. At a low caterpillar density (20 caterpillars on 10 Lima bean leaves), the predators were significantly more attracted to volatiles from infested leaves on which the caterpillars and their products were present or from infested leaves from which the caterpillars and their products had been removed when compared to volatiles from uninfested leaves. The predators, however, significantly avoided odors from 20 caterpillars and their products (mainly feces) removed from bean leaves. In contrast, at a higher caterpillar density (100 caterpillars on 10 Lima bean leaves), the predators avoided volatiles from caterpillar-infested bean leaves. Volatiles from infested leaves from which the caterpillars and their products had been removed were not preferred over volatiles from uninfested leaves. Volatiles from feces collected from 100 caterpillars were strongly avoided by the predators, while the behavior of the predatory mites was not affected by volatiles from 100 caterpillars removed from a plant. The data show that carnivorous arthropods may avoid nonprofitable herbivores. This avoidance seems to result from an interference of volatiles from herbivore products with the attraction to herbivore-induced plant volatiles.
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  • 89
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    Journal of chemical ecology 25 (1999), S. 2547-2559 
    ISSN: 1573-1561
    Keywords: Yponomeuta cagnagellus ; ermine moth ; Lepidoptera ; speciation ; specialization ; plant surface compounds ; oviposition ; host discrimination ; Euonymus europaeus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Yponomeuta cagnagellus is a phytophagous moth species specialized on Euonymus europaeus. Host discrimination by the adult female is an important aspect of host specialization and is based mainly on the distinctive secondary chemistry of host and nonhosts. This paper describes a bioassay that was developed to study the effect of isolated plant surface compounds on Yponomeuta oviposition. Adult moths recognize their hosts through chemical stimuli on the leaf or twig surface. Relatively apolar compounds extracted from the host twig surface by washing in dichlormethane do not stimulate oviposition. More polar, methanol-soluble compounds do, and this stimulation is dose dependent. Moths are able to recognize hosts solely by their surface compounds: females show a strong preference for artificial twigs treated with methanolic extracts of their hosts compared to those treated with methanolic extracts of nonhosts Crataegus monogyna and Prunus spinosa (both of which are hosts for closely related Y. padellus). Shape and surface characteristics of the oviposition substrate also influence oviposition. The substrate needs to resemble the basic form of a twig (i.e., cylindrical), and females prefer a coarse surface with irregularities over a smooth one.
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  • 90
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Lobesia botrana ; grapevine moth ; wind tunnel ; behavior ; flight track recording ; (E)-7,(Z)-9-dodecadienyl acetate ; (E)-7,(Z)-9-dodecadien-1-ol ; (Z)-9-dodecenyl acetate ; (E)-9-docecenyl acetate ; 11-dodecenyl acetate ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The behavioral responses of Lobesia botrana males to calling females, pheromone gland extracts, and synthetic sex pheromones were recorded in a wind tunnel. Gland extracts and synthetic pheromones were released from a pheromone evaporator. The numbers of males reaching the source and their flight tracks in response to calling females and pheromone gland extracts were compared to those of synthetic blends. Upwind flights to natural sex pheromone were straighter and faster than to a three-component blend of (E)-7,(Z)-9-dodecadienyl acetate (E7,Z9–12:Ac), (E)-7,(Z)-9-dodecadien-1-ol (E7,Z9–12:OH), and (Z)-9-docecenyl acetate (Z9–12:Ac) (100:20:5). The optimum ratio of E7,Z9–12:OH and Z9–12:Ac to E7,Z9–12:Ac was found to be 5% and 1%, respectively. An additional seven compounds identified in the sex pheromone gland were investigated for their biological activity. Two unsaturated acetates, i.e., (E)-9-dodecenyl acetate (E9–12:Ac) and Δ11-dodecenyl acetate (Δ11–12:Ac), increased the number of males reaching the source as well as straightness, linear velocity, and decreased the track angle of upwind flight. Optimum response was obtained by releasing 10 pg/min E7,Z9–12:Ac in a mixture with 0.5 pg/min E7,Z9–12:OH, 0.1 pg/min Z9–12:Ac, 0.1 pg/min E9– 12:Ac and 1 pg/min Δ11-12–Ac. The saturated acetates previously identified in the female glands were biologically inactive.
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  • 91
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    BioMetals 12 (1999), S. 289-294 
    ISSN: 1572-8773
    Keywords: accumulation ; gold ; proton efflux ; Saccharomyces cerevisiae ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This paper examines the effects of ionic gold on Saccharomyces cerevisiae, as determined by long-term (growth in gold-containing media) and short-term interactions (H+ efflux activity). An increasing gold concentration inhibited growth and at 〈0.2 mM Au, growth was not observed. Transmission electron microscopy revealed no differences in ultrastructure but fine electron dense particles were observed in unstained preparations from gold-containing medium. After glucose addition (to 10mM) to starved suspensions of S. cerevisiae, glucose-dependent reduction of external pH occurred as the cells extruded protons. In the presence of increasing gold concentrations, the lag time before proton extrusion did not change but the rate and duration decreased significantly with a marked influence on proton efflux rate being observed at ≤ 10 μM. Extension of preincubation time of yeast cells in gold-containing medium resulted in a decreasing proton efflux rate and colloidal phase formation in the cell suspensions, the time between gold addition and the beginning of colloidal phase formation depending on the gold concentration used. Both Ca and Mg enhanced the inhibitory effect of gold on the yeast cells with Ca showing a stronger inhibitory effect than Mg.
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  • 92
    ISSN: 1570-7458
    Keywords: host suitability ; acceptance ; biological control ; new associations ; Lepidoptera ; Pyralidae ; New World ; Old World ; stemborers ; Braconidae ; larval parasitoids ; Gramineae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The present study examined the acceptability and suitability of Old World stemborers (Chilo partellus and C. orichalcociliellus) for the development of New World parasitoids (Apanteles deplanatus and A. minator) and New World stemborers (Diatraea saccharalis and D. grandiosella) for the development of Old World parasitoids (Cotesia sesamiae, C. flavipes and C. chilonis). Results revealed that acceptance and suitability were high in old associations. In new associations, parasitoids accepted about 60% of the new association hosts. In addition, 10 out of 17 new associations were successful. Apanteles species appeared to be more physiologically host specific than Cotesia species. For example, two of four new association hosts were accepted by A. deplanatus and only one (D. saccharalis) was partially suitable for progeny development. Among the Cotesia species, Cotesia flavipes appeared to have a wider host range than the two other species. It attacked all hosts offered and successfully parasitized all but one (D. grandiosella). Diatraea saccharalis was accepted and was a suitable host for the development of all parasitoid species tested, whereas D. grandiosella was unsuitable for the development of four out of five parasitoid species tested. No clear pattern was observed as behavioral acceptance did not always agree with the pattern of physiological suitability. Implications of these findings for importation biological control of stemborers are discussed.
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  • 93
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    Entomologia experimentalis et applicata 91 (1999), S. 187-194 
    ISSN: 1570-7458
    Keywords: oviposition ; strategy ; catastrophe ; theory ; clutch ; Lepidoptera ; optimization ; dynamic ; bet hedging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We developed state-dependent life-history theory to explain the variance in clutch size decisions made by insect herbivores under a variety of ecological scenarios. An important aspect of our theory is explicit representation of the distribution of host quality and frequency of occurrence. Examination of the theory suggests that clutch size decisions can be highly non-linear with respect to host quality and variability. We then use our theory to explore the potential for bet-hedging strategies to evolve as a function of unpredictable catastrophic events that decimate entire clutches. Our analysis suggests that the benefits to employing such a strategy will frequently be outweighed by costs brought on by delayed oviposition.
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    Entomologia experimentalis et applicata 91 (1999), S. 287-295 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; oviposition ; host deprivation ; lightbrown apple moth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of mating, age at mating, the presence or absence of a plant leaf, and the deprivation of a suitable ovipositional substrate during when the first ovipositional bout after mating would normally take place, on the lifetime fecundity and fertility (percentage of fertile eggs laid) of female Epiphyas postvittana were investigated. Mating had a significant effect on lifetime fecundity, with mated females laying 2.5 times more eggs than virgin females. Age at mating had a significant effect on both fecundity and fertility, both declining with increasing age when the female was mated. In the presence of a leaf of C. japonica, mated females had a greater lifetime fecundity than when no leaf was present; females in the presence of a C. japonica leaf consistently laid more eggs each day during the first 4–6 days after mating than females without a leaf. When females were deprived of a suitable ovipositional substrate, for the first 22 h after mating, they were significantly less fecund over their lifetime than were control females. Finally, in no-choice tests with three plants of different acceptability to females, the fecundity of females differed in the order C. japonica 〉 Urtica ferox 〉 Tibouchina multiflora. This different fecundity appeared to be inversely related to the pubescence of the leaves, suggesting that leaf texture may be a suitable antixenotic resistance factor for crops to be protected from this insect. These results suggest that strategies whereby mating is delayed or oviposition reduced within a critical period after mating, may result in significant reductions in pest populations.
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  • 95
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    Entomologia experimentalis et applicata 92 (1999), S. 53-62 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; host selection ; correlation ; lightbrown apple moth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The polyphagous leafroller moth, Epiphyas postvittana, is a pest of many fruit crops in New Zealand. Since the larva is highly mobile, host selection in this insect may involve both the adult female and the larva. In order to test the relative importance of the adult female and the neonate larva in the selection of host plants, the ovipositional preferences of females, and the preferences or acceptances of neonate larvae towards 26 plant species, consisting of 15 plants considered hosts and 11 not considered hosts, were investigated. In the ovipositional tests, the mean preferences of females for hosts and non-hosts were very similar. In contrast, larvae showed a significantly greater mean preference or acceptance towards hosts than to non-hosts, in both choice and no-choice bioassays, respectively. There were highly significant correlations between the preferences and acceptances of larvae for plants in the choice and no-choice tests. In the no-choice tests, there was a highly significant correlation between the acceptances of neonate larvae towards plants after one and three days (i.e., acceptances changed little over time). Moreover, in these no-choice tests, there was a significant negative correlation between larval acceptance at 1 day and larval mortality after 3 days; that is, the less acceptable a given plant at 1 day, the more likely larvae would fail to establish, feed, and survive on it by three days. Female and larval preferences towards the various plants were also negatively correlated. Together, these data suggest that the selection of a plant for the neonate larva to feed on is largely governed by the preferences of the larva, rather than by the preferences of the female. However, selection of a plant for oviposition by the female, may be important in host selection for reasons unrelated to larval preferences, for example, by encouraging dispersal, perhaps to other plant species, of the neonate larvae and thereby decreasing intersibling competition.
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    Entomologia experimentalis et applicata 92 (1999), S. 321-330 
    ISSN: 1570-7458
    Keywords: rush moth ; Juncus squarrosus ; fluctuating food resources ; ‘bet-hedging’ ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult emergence in Coleophora alticolella held at 15 °C was accelerated by exposure to L18:D6 in autumn and midwinter. The effect decreased during winter and exposure of individuals, held at low temperature over winter, to L18:D6 or L6:D18 at 15 °C at the end of March resulted in the same mean emergence date. Long daylength experienced at 5 °C did not promote emergence nor did exposure to low temperature during winter. The number of adults emerging increased with the length of time cultures were held on short day but was always below 50% of the larvae. When larvae were exposed to L18:D6 and L6:D18 at 15 °C at the end of March, on long day 61% adults emerged and 39% remained in diapause, whereas on short day, 25% became adult and 75% remained diapausing larvae. The possibility of cohort splitting, with some individuals undergoing prolonged diapause, is discussed.
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  • 97
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Yponomeutidae ; Plutella xylostella ; parasitoid ; Hymenoptera ; Braconidae ; Cotesia plutellae ; foraging behaviour ; wind tunnel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The braconid Cotesia plutellae is an important larval parasitoid of the diamondback moth (Plutella xylostella), a major pest of crucifers in the tropics and sub-tropics. The in-flight searching behaviour of C. plutellae was investigated in a wind tunnel and the close-range attack behaviour observed in cages. The relative importance of volatile stimuli emanating from the plant-host-complex, oilseed rape (Brassica napus) – P. xylostella, in the long-range attraction of C. plutellae was investigated. Plants that were mechanically damaged, or damaged by P. xylostella larvae, were attractive to the parasitoid. Host-damaged leaves remained attractive to the parasitoid after removal of the host larvae. These results indicate that C. plutellae predominantly uses plant derived stimuli in its in-flight searching behaviour. An oviposition experience or contact with a host-damaged leaf prior to the bioassay significantly increased the response to these volatile cues. The foraging behaviour of C. plutellae is compared with other braconid larval parasitoids attacking lepidopteran hosts on crucifers.
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  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 190 (1999), S. 47-54 
    ISSN: 1573-4919
    Keywords: calmodulin ; yeast calmodulin ; Ca2+ binding ; Ca2+ binding protein ; Saccharomyces cerevisiae ; interdomain interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Calmodulin of Saccharomyces cerevisiae has different Ca2+ binding properties from other calmodulins. We previously reported that the maximum number of Ca2+ binding was 3 mol/mol and the fourth binding site was defective, which was different from 4 mol/mol for others. Their macroscopic dissociation constants suggested the cooperative three Ca2+ bindings rather than a pair of cooperative two Ca2+ bindings of ordinary calmodulin. Here we present evidence for yeast calmodulin showing the intramolecular close interaction between the N-terminal half domain and the C-terminal half domain, while the two domains of ordinary calmodulin are independent of each other. We will discuss the relationship of the shape and the shape change caused by the Ca2+ binding to the enzyme activation in yeast. The functional feature of calmodulin in yeast will also be considered, which might be different from the one of vertebrate calmodulin.
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  • 99
    ISSN: 1572-9788
    Keywords: lectins ; insect resistance ; transgenic plants ; potato (Solanum tuberosum) ; Lepidoptera ; Homoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of concanavalin A (ConA), a glucose/mannose-specific lectin from jackbean (Canavalia ensiformis), on insect crop pests from two different orders, Lepidoptera and Homoptera, were investigated. When fed to larvae of tomato moth (Lacanobia oleracea) at a range of concentrations (0.02–2.0% of total protein) in artificial diet, ConA decreased survival, with up to 90% mortality observed at the highest dose level, and retarded development, but had only a small effect on larval weight. When fed to peach-potato aphids (Myzus persicae) at a range of concentrations (1–9μM) in liquid artificial diet, ConA reduced aphid size by up to 30%, retarded development to maturity, and reduced fecundity (production of offspring) by 〉35%, but had little effect on survival. With both insects, there was a poor correlation between lectin dose and the quantitative effect. Constitutive expression of ConA in transgenic potatoes driven by the CaMV 35S promoter resulted in the protein accumulating to levels lower than predicted, possibly due to potato not being able to adequately reproduce the post-translational processing of this lectin which occurs in jackbean. However, the expressed lectin was functionally active as a haemagglutinin. Bioassay of L. oleracea larvae on ConA-expressing potato plants showed that the lectin retarded larval development, and decreased larval weights by 〉45%, but had no significant effect on survival. It also decreased consumption of plant tissue by the larvae. In agreement with the diet bioassay results, ConA-expressing potatoes decreased the fecundity of M. persicae by up to 45%. ConA thus has potential as a protective agent against insect pests in transgenic crops.
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 13 (1999), S. 709-719 
    ISSN: 1573-8477
    Keywords: Anthocharis cardamines ; aposematism ; Lepidoptera ; palatability ; Pieridae ; Pieris brassicae ; P. napi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been suggested that the white coloration of Pieridae butterflies is a warning signal and therefore all white Pieridae could profit from a mimetic resemblance. We tested whether green-veined white (Pieris napi) and orange-tip (Anthocharis cardamines) butterflies benefit from white coloration. We compared their relative acceptability to wild, adult pied flycatchers (Ficedula hypoleuca) by offering live A. cardamines and P. napi together with two non-aposematic butterflies on the tray attached to birds' nesting boxes. Experienced predators equally attacked white and non-white butterflies, and the order of attack among the Pieridae was random. If anything, there was a slight indication that the female A. cardamines was the least favoured prey. Since birds did not avoid white coloration, we compared the palatability of these two species against known palatable and unpalatable butterflies by presenting them to great tits (Parus major). Pieris brassicae, which has been earlier described as unpalatable, was also included in the palatability test. However, there were no significant differences in the palatability of the butterflies to birds, and even P. brassicae was apparently palatable to the great tits. Our results do not unambiguously support the hypothesis that the white coloration of Pieridae would signal unpalatability. Nevertheless, in our last experiment, pied flycatchers often rejected or left untouched free flying P. napi and A. cardamines. This suggests that other features in a more natural situation, such as the agile flight pattern or odours might still make them unprofitable to birds.
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