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  • Gas chromatography  (280)
  • Drosophila  (266)
  • Springer  (546)
  • Cell Press
  • 1985-1989  (322)
  • 1980-1984  (224)
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  • 1
    ISSN: 1432-1432
    Keywords: Drosophila ; Foldback element ; Transposable element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Foldback elements are a family of transposable elements described inDrosophila melanogaster. The members of this dispersed repetitive family have terminal inverted repeats that sometimes flank a central region. The inverted repeats of all the family members are homologous. The study of the distribution and conservation of the foldback elements in differentDrosophila species shows that this distribution is different from that of the hybrid dysgenesis systems (PM and IR). Sequences homologous to foldback elements were observed by Southern blots and in situ hybridization in all species of themelanogaster subgroup and in some species of themontium andtakahashii subgroups. The element was probably already present before the radiation of these subgroups. No evidence of horizontal transmission of the foldback element could be observed.
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  • 2
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    Development genes and evolution 198 (1989), S. 227-232 
    ISSN: 1432-041X
    Keywords: Campaniform sensilla ; Drosophila ; Achaete-scute complex ; Cis regulatory sites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analysed the role of the achaete-scute gene complex in the development of the pattern of campaniform sensilla on the wing blade of Drosophila. We show that the complete pattern results from the superimposition of two independent subpatterns, one of which depends on the achaete gene and the other on scute. The scute subpattern comprises several clusters of sensilla, most of which seem to require the presence of control regions located upstream of the transcribed region. This is in contrast with the pattern of scute-dependent bristles, most of which depends on control elements located downstream of the transcribed region.
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  • 3
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    Development genes and evolution 198 (1989), S. 65-77 
    ISSN: 1432-041X
    Keywords: Cell communication ; Pattern formation ; Cell differentiation ; trans-regulatory genes ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects ofpolyhomeotic (ph) mutants in imaginal cells have been studied in a clonal analysis. Clones of cells, homozygous forph, sort-out after a few divisions, probably as a consequence of modified cell affinities. The dorso-ventral margin of the wing has special characteristics that retard this phenomenon. The formation and exclusion of a clone of 8–16 cells affect the polarity of the wild-type neighbour cells and can provoke pattern triplications. The results suggest that a defect in intercellular communication prevents the wild-type cells from maintaining coordinated positional information. The cells react by regenerative growth, and reorganize into a new pattern. The pleiotropic phenotypes ofph mutants are explained according to a common hypothesis aboutph + function.
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  • 4
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    Development genes and evolution 198 (1989), S. 157-169 
    ISSN: 1432-041X
    Keywords: Distal less ; Limb development ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of all of the adult limbs inDrosophila depends upon the activity of theDistal-less gene. We report here the phenotypic characterization of a number of hypomorphicDistal-less alleles which indicates that there is a graded requirement forDistal-less activity in the developing limbs. Previous analysis of genetically mosaic animals indicated that cells in the early primordia of the limb imaginal dises possess a graded proximal-distal positional information which depends on the presence of theDistal-less gene for its expression. Taken together these data suggest thatDistal-less may directly encode the graded positional information that is required to organise the proximal-distal axis of the developing limbs.
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  • 5
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    Development genes and evolution 198 (1989), S. 185-190 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Follicle cells ; Egg shell ; Ovarian tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental potential of the cells of the somatic follicular epithelium (follicle cells) was studied in mutants in which the differentiation of the germ-line cells is blocked at different stages of oogenesis. In two mutants, sn 36a and kelch, nurse cell regression does not occur, yet the follicle cells around the small oocyte continue their normal developmental program and produce an egg shell with micropylar cone and often deformed operculum and respiratory appendages. Neither the influx of nurse cell cytoplasm into the oocyte nor the few follicle cells covering the nurse cells are apparently required for the formation of the egg shell. In the tumor mutant benign gonial cell neoplasm (bgcn) the follicle cells can also differentiate to some extent although the germ-line cells remain morphologically undifferentiated. Vitelline membrane material was synthesized by the follicle cells in some bgcn chambers and in rare cases a columnar epithelium, which resembled morphologically that of wild-type stage-9 follicles, formed around the follicle's posterior end. The normal polarity of the follicular epithelium that is characteristic for mid-vitellogenic stages may, therefore, be established in the absence of morphologically differentiating germ-line cells. However, the tumorous germ-line cells do not constitute a homogeneous cell population since in about 30% of the analyzed follicles a cell cluster at or near the posterior pole can be identified by virtue of its high number of concanavalin A binding sites. This molecular marker reveals an anteroposterior polarity of the tumorous chambers. In follicles mutant for both bgcn and the polarity gene dicephalic the cluster of concanavalin A-stained germ-line cells shifts to more anterior positions in the follicle.
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  • 6
    ISSN: 1432-1939
    Keywords: Drosophila ; Microbial associations ; Resource partitioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distributions of five Drosophila species and four components of the microflora have been compared across a total of 48 traps baited with four different fruit and vegetable substrates in two domestic compost heaps in Canberra (Australia). Large and consistent differences are found, both among the Drosophila and among the microbial classes, in their distributions across traps baited with different substrates. Moreover the distribution of each Drosophila species shows a unique set of strong associations with the microbial distributions. Thus the distributions of both D. simulans and D. melanogaster are found to be strongly negatively correlated with the abundance of bacteria while D. simulans is also strongly positively correlated with the titre of fermenter yeasts. D. immigrans is strongly positively correlated both with bacteria and with non-fermenter yeasts. D. hydei is positively correlated with nonfermentery yeasts and D. busckii is negatively correlated with fermenter yeasts. Moulds are the only microbial class not consistently associated with the distribution of any of the Drosophila species. The correlations with the other microbial classes are sufficient to explain the majority of the abundance differences of the Drosophila species among the trap types. It is therefore proposed that the clear partitioning of the fruit resources by the Drosophila is due to their differing primary interactions with the microflora.
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  • 7
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    Journal of comparative physiology 166 (1989), S. 179-187 
    ISSN: 1432-1351
    Keywords: Blowfly ; Drosophila ; Photoreceptor ; Lanthanum ; trp mutant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of lanthanum on the light response of blowfly (Calliphora erythrocephala) photoreceptors was studied. The electrophysiological behaviour of the photoreceptors in the presence of La can be summarized as follows: 1. Upon long stimulation the photoreceptors responded with a ‘transient receptor potential’, i.e. the cells depolarized at the onset of the stimulus and then repolarized to (or below) the resting potential. This effect was dependent on stimulus intensity and occurred only at high intensities. During illumination membrane noise was reduced. 2. The light-induced changes in membrane potential were paralleled by changes in membrane resistance. 3. The time course of the receptor response was slowed down. 4. Light adaptation led to an increase in response latency. 5. The recovery of the receptor response after light adaptation was slowed down. 6. The sensitivity of the receptor cells measured by the response to short light stimuli was reduced. In summary, the electrophysiological behaviour of Calliphora photoreceptors in the presence of La was very similar to that of the photoreceptors of the trp (transient receptor potential) mutant of Drosophila melanogaster. This result suggests that La and trp mutation affect the same cellular processes in the photoreceptors.
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  • 8
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    Ecological research 4 (1989), S. 209-218 
    ISSN: 1440-1703
    Keywords: Annual life cycle ; Drosophila ; Fungus preference ; Nematode parasitism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Food preferences and nematode parasitism were studied in natural populations of mycophagousDrosophila in and near Sapporo, northern Japan. Species which preferred fresh mushrooms showed species-specific responses toPleurotus mushrooms:D. pirka bred only onPleurotus cornucopiae, D. trivitata onP. cornucopiae andP. ostreatus, D. trilineata on these twoPleurotus mushrooms and some other mushrooms, whileD. sexvittata bred on a wide variety of mushrooms but seldom onPleurotus mushrooms. Species which preferred decayed mushrooms (D. quadrivittata, D. histrioides, D. testacea and species of thequinaria species-group) showed host preferences different from those of the above species. The rate of parasitism by nematodes was generally higher in species which prefer decayed mushrooms than in species which prefer fresh mushrooms. Among species which prefer fresh mushrooms, onlyD. trilineata was parasitized frequently by nematodes. It was not clear what factors determine the rate of parasitism in these mycophagousDrosophila. D. pirka, D. trivittata andD. trilineata passed through three or four generations per year and entered reproductive diapause in early September in and near Sapporo.
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  • 9
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    Molecular and cellular biochemistry 90 (1989), S. 27-35 
    ISSN: 1573-4919
    Keywords: zerknullt gene ; homeobox protein ; Drosophila ; filter binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The region upstream from the zerknullt (zen) gene contains three sites that specifically bind the zen protein product of the gene. Evidence for these binding sites was obtained by the filter binding technique and the DNase footprinting technique. The filter binding technique was used to scan various segments of DNA for the presence of possible specific binding sites. Segments that were selectively retained by the filter binding technique invariably contained one or more specific binding sites according to the DNase footprinting technique. Two of the zen protein binding sites were spaced only 30 base pairs apart. These sites could be separated without any loss in their specific binding properties. It is concluded that these two sites function independently in the binding of zen protein.
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  • 10
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    Biochemical genetics 27 (1989), S. 507-520 
    ISSN: 1573-4927
    Keywords: Drosophila ; sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) ; glue proteins ; glycosylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The patterns of protein fractions from total salivary glands and from glue plugs were compared in seven members of theDrosophila nasuta subgroup by the use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The glue protein patterns are member specific concerning the numbers and the electrophoretic mobilities of major and minor glue protein fractions. However, the major fractions of all subgroup members could be grouped into five SDS-PAGE domains according to the homologies of their electrophoretic mobilities, prominence of Coomassie blue staining, and PAS reaction. In all subgroup members, major fractions are involved in posttranslational modifications into larger protein molecules of the final glue. Quantitative estimations of the glue proteins inD. n. nasuta andD. n. albomicans reveal that they constitute between 55 and 60% of the total salivary gland proteins, whereas inD. melanogaster and inD. hydei the fraction is only 32 and 35%, respectively.
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  • 11
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    Biochemical genetics 27 (1989), S. 507-520 
    ISSN: 1573-4927
    Keywords: Drosophila ; sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) ; glue proteins ; glycosylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The patterns of protein fractions from total salivary glands and from glue plugs were compared in seven members of theDrosophila nasuta subgroup by the use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The glue protein patterns are member specific concerning the numbers and the electrophoretic mobilities of major and minor glue protein fractions. However, the major fractions of all subgroup members could be grouped into five SDS-PAGE domains according to the homologies of their electrophoretic mobilities, prominence of Coomassie blue staining, and PAS reaction. In all subgroup members, major fractions are involved in posttranslational modifications into larger protein molecules of the final glue. Quantitative estimations of the glue proteins inD. n. nasuta andD. n. albomicans reveal that they constitute between 55 and 60% of the total salivary gland proteins, whereas inD. melanogaster and inD. hydei the fraction is only 32 and 35%, respectively.
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  • 12
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    Biochemical genetics 27 (1989), S. 263-277 
    ISSN: 1573-4927
    Keywords: Drosophila ; kinetic plate reader ; enzyme polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Techniques for performing numerous enzyme kinetic assays with minimum time and effort would be valuable to studies of the evolutionary genetics of metabolic control and the quantitative genetics of determinants of kinetic parameters. Microtiter plate readers have been used for a variety of repetitious analytical techniques, and instruments are available that can take repetitive readings with sufficient speed to perform kinetic assays. The ability of these instruments to assay rapidly the kinetic properties of small samples makes them potentially useful for a number of problems in population genetics. While the ability to handle large numbers of samples is very attractive, the small sample volumes and optical imprecision of microtiter plates result in some sacrifice in accuracy. This paper presents methods for performing kinetic assays on individual field-caughtDrosophila, quantifies the precision of these methods, and characterizes differences amongDrosophila melanogaster andD. simulans from samples caught in California and Pennsylvania. Comparisons between field-caught and laboratory rearedD. melanogaster show that most of the characters are very similar, with the exception of αGPDH, which has a threefold higher mean activity among field-caught flies. The phenotypic correlations are presented with a brief discussion of their relevance to assessing the evolution of metabolic control of these enzymes.
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  • 13
    ISSN: 1573-4927
    Keywords: Drosophila ; aldox-2 ; molybdoenzymes ; sulfite oxidase ; molybdenum ; tungsten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mutation at thealdox-2 locus inDrosophila melanogaster affects the specific activities of four molybdoenzymes differentially during development. Sulfite oxidase activity is normal during late larval and pupal stages but is reduced during early adult stages inaldox-2 organisms. There was complete concordance among the effects ofaldox-2 on sulfite oxidase, aldehyde oxidase, xanthine dehydrogenase, and pyridoxal oxidase, when 38 stocks were analyzed which were derived from single recombination events betweenc andpx, markers which flankaldox-2. Several different biochemical analyses indicate that the active molybdoenzymes present in thealdox-2 strain are normal with respect to size, shape,pH-activity profile,K m , and molecular weight. Significant differences were found between thealdox-2 strain and the OR control strain in their responses to dietary Na2MoO4 and Na2WO4. The mutant strain is much more resistant to the effects of dietary Na2WO4 and much more responsive to the administration of Na2MoO4 than the OR control strain when these effects are quantitated by measurements of molybdoenzyme specific activities. This evidence suggests that thealdox-2 + gene product has a molybdenum binding site which can also bind tungsten and that this site is altered in the mutant strain. The hypothesis presented explains the observed effects of thealdox-2 mutation and relates them to the other mutations reported in this gene-enzyme system.
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  • 14
    ISSN: 1573-3297
    Keywords: Drosophila ; circadian clock ; ultradian oscillations ; disconnected mutant ; visual system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Free-running locomotor activity and eclosion rhythms ofDrosophila melanogaster, mutant at thedisconnected (disco) locus, are substantially different from the wild-type phenotype. Initial periodogram analysis revealed little or no rhythmicity (Dushayet al., 1989). We have reanalyzed the locomotor activity data using high-resolution signal analysis (maximum-entropy spectral analysis, or MESA). These analyses, corroborated by autocorrelograms, uncovered significant residual circadian rhythmicity and strong ultradian rhythms in most of the animals tested. In this regard thedisco mutants are much like flies expressing mutant alleles of theperiod gene, as well as wild-type flies reared throughout life in constant darkness. We hypothesize that light normally triggers the coupling of multiple ultradian oscillators into a functional circadian clock and that this process is disrupted indisco flies as a result of the neural lesion.
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  • 15
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    Theoretical and applied genetics 77 (1989), S. 123-127 
    ISSN: 1432-2242
    Keywords: Inbreeding depression ; Drosophila ; Natural selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This experiment was designed to study the relationship between rate of inbreeding and observed inbreeding depression of larval viability, adult fecundity and cold shock mortality in Drosophila melanogaster. Rates of inbreeding used were full-sib mating and closed lines of N=4 and N=20. Eight generations of mating in the N=20 lines, three generations in the N=4 lines and one generation of full-sib mating were synchronised to simultaneously produce individuals with an expected level of inbreeding coefficient (F) of approximately 0.25. Inbreeding depression for the three traits was significant at F=0.25. N=20 lines showed significantly less inbreeding depression than full-sib mated lines for larval viability at approximately the same level of F. A similar trend was observed for fecundity. No effect of rate of inbreeding depression was found for cold shock mortality, but this trait was measured with less precision than the other two. Natural selection acting on loci influencing larval viability and fecundity during the process of inbreeding could explain these results. Selection is expected to be more effective with slow rates of inbreeding because there are more generations and greater opportunity for selection to act before F=0.25 is reached. Selection intensities seem to have been different in the three traits measured. Selection was most intense for larval viability, less intense for fecundity and, perhaps, negligible at loci influencing cold shock mortality.
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  • 16
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    Theoretical and applied genetics 77 (1989), S. 253-259 
    ISSN: 1432-2242
    Keywords: Heterosis ; Selection ; Drosophila ; Genotype x environment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Experiments were designed to examine whether heterosis would occur in crosses of Drosophila melanogaster populations adapted to 18 °C or 28 °C environments. Crosses were examined in parental environments, an intermediate environment (23 °C) and a mixed environment (alternating 18°/28°C). Parental populations did not show divergence for larval viability, cold shock or high temperature mortalities when tested in a common environment. However, the 28 °C population was less fecund than the 18 °C population, but had higher larval competitive ability and higher adult longevity. Heterosis for viability, cold shock mortality and high temperature mortality occurred in crosses between a population adapted to 18 °C and another adapted to 28 °C, but not in crosses between two populations adapted to the same temperature. The results suggest that, in the absence of drift, heterosis is expected in crosses between lines or populations with different histories of selection but not between lines with the same selection histories.
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  • 17
    ISSN: 1617-4623
    Keywords: Drosophila ; Vestigial ; Dihydrofolate reductase ; Aminopterin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Vestigial (vg) mutants of Drosophila melanogaster are characterized by atrophied wings. In this paper we show that: (1) aminopterin an inhibitor of dihydrofolate reductase (DHFR) and fluorodeoxyuridine (FUdR), an inhibitor of thymidylate synthetase induce nicks in the wings of wild-type flies and phenocopies of the vg mutant phenotype when vg/+ and vg B/+ flies are reared on these substances (vgB is a deficiency of the vg locus). Only thymidine and thymidylate can rescue the flies from the effect of aminopterin. We propose that the vg phenotype is due to a decrease in the dTMP pool in the wings. (2) Mutant vg strains yield more offspring on medium containing aminopterin than on normal medium. The resistance of vg larvae to the inhibitor seems specific to the gene. This is the first case of aminopterin resistance in living eucaryotes. In contrast sensitivity of the vg larvae to FUdR is observed. (3) An increase in the activity and amount of DHFR is observed in mutant strains as compared with the wild-type flies. Our data suggest that the vg + gene is a regulatory gene acting on the DHFR gene or a structural gene involved in the same metabolic pathway.
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  • 18
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    Molecular genetics and genomics 218 (1989), S. 118-126 
    ISSN: 1617-4623
    Keywords: Drosophila ; Regulation ; yellow gene ; Germline transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have assessed the DNA sequence requirements for the correct spatial pattern and phenotypic expression of y in the late embryo/larvae. The wild-type larval phenotype requires both the regions between-294 bp and-92 bp and a portion of the intron; the sequence element(s) located within the intron can act in a position independent manner to effect the wild-type larval phenotype. The larval expression pattern was examined by tissue experiments in situ and by staining germline transformants derived from various y/lacZ fusion constructs. The larval expression of y is restricted to the mouthparts, microsetae and anal plates. While the-495 bp to+194 bp region alone cannot effect a wild-type larval expression pattern, this region in conjunction with the intron appears to be sufficient to drive β-gal expression in an essentially wild-type pattern. Our data further suggest that the-294 bp to-92 bp region contains elements which specify the larval pattern and that the element(s) in the intron normally act to enhance the level of expression necessary for the wild-type larval phenotype. We also present a phenotypic analysis of the adult cuticle structures of germline transformants derived from a variety of deletion and rearrangement constructs of the y gene. This analysis has revealed several new features associated with the regulation of y expression.
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  • 19
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    Molecular genetics and genomics 215 (1989), S. 281-285 
    ISSN: 1617-4623
    Keywords: Drosophila ; achaete-scute complex ; myc ; Protein domains ; Genomic search
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Several genes of the achaete-scute complex (ASC) of Drosophila melanogaster encode a 60 amino acids long conserved domain which shares a significant homology with a region of the vertebrate myc proteins. Based on these results, the existence of a family of Drosophila genes that would share both this conserved domain and the neurogenic function of the AS-C has been postulated. To test this proposal, we have searched a D. melanogaster genomic library with a probe that encodes the conserved domain. Only under very low stringency hybridization conditions, clones not belonging to the AS-C cross-hybridized with the probe. Those that gave the strongest signals were characterized. Sequencing of the cross-hybridizing regions showed that they had no significant homology with the conserved domain, the sequence similarity extending at the most for 37 nucleotides. Although our results do not conclusively disprove the existence of a family of AS-C-like genes, they indicate that the conservation of the domain would be lower than that found for shared motifs in other families of Drosophila developmental genes.
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  • 20
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    Chromatographia 27 (1989), S. 37-43 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Methylbromide ; Charcoal tubes ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Air sampling of methylbromide using 900 mg HBr-treated activated charcoal tubes, followed by solvent desorption and FID or ECD chromatographic analysis, makes it possible to evaluate concentrations ranging from 0.2 ppm (1 mg×m−3) to 250 ppm (1g×m−3) at ambient temperature even with a high hygrometric level. Thermal desorption does not lead to satisfactory results.
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  • 21
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    Chromatographia 27 (1989), S. 60-66 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Mass loadability ; Stationary phase capacity ; Capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In GLC the mass load can be normalized with respect to the amount of stationary phase in one plate. This quantity can be used for a specified solute-liquid phase combination in any capillary or packed column, irrespective of the column dimensions or the number of plates. For each individual solute in a given stationary phase a unique factor β″ can be found, which accounts for the specific shape of the isotherm of this particular combination. this factor β″ corresponds well with the activity coefficients of the solutes in the stationary phase, by which a fairly good approximation of the mass loadability of the column at hand can be made without need for experiment.
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  • 22
    ISSN: 1573-8477
    Keywords: Genetic elements ; isozymes ; life span ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of electrophoretic loci shows that at least four differences exist in isozymes of long- and short-lived populations ofD. melanogaster, descended by selection from a common ancestral stock. Adults of longlived populations differ in gene dosage of phosphoglucomutase (PGM), NAD malate dehydrogenase (MHD), NADP malic enzyme (ME) and by additional mobility variants of glucose-6-phosphate dehydrogenase (G6PD). Larvae, however, differ only by variants of G6PD. The differences in these enzymes, considered together with the greater flight endurance that long-lived populations have shown elsewhere, suggest that increased glycogen synthesis plays a significant role in the improved life span of selected populations. Adaptation to selection for increased life span may, therefore, derive from an improved ability to use dietary sucrose in the media provided. The distribution of electrophoretic loci agrees with the results of a study indicating the position of genetic elements contributing to life span.
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  • 23
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    Evolutionary ecology 3 (1989), S. 189-201 
    ISSN: 1573-8477
    Keywords: Developmental homeostasis ; life history traits ; Drosophila ; breeding site variation ; cactus ; Sonoran desert
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Variation in life histories among populations of cactophilicDrosophila mojavensis has been hypothesized to be a by-product of a shift to one of two alternate host plants. When cultured on the ancestral and a secondary host cactus, a Baja population expressed shorter development times and smaller thorax sizes than a mainland population, but viability did not differ. Comparisons with all reciprocal F1 and F2 crosses between populations revealed that genetic differences in development time and thorax size were largely additive. Homeostasis in these life history traits was population specific, except for viability. Homeostasis in development time was greater in the Baja population than in the other crosses, suggesting dominance for decreased homeostasis in the mainland population. Underdominance in viability homeostasis of the F1 hybrids suggested some incompatibility between populations. Homeostasis in thorax size was greater in females than in males and differed among parental populations. Maintenance of heritable differences and genetic variation for homeostasis in these traits suggested a role for cactus-specific differences in environmental uncertainty caused by variation in breeding site duration and abundance in nature.
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  • 24
    ISSN: 1617-4623
    Keywords: Chromosomal walking ; Cut locus ; Drosophila ; Unstable mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have cloned from the Oregon R strain of Drosophila melanogaster a 240 kb segment of DNA that contains the cut (ct) locus, and characterized the region for the presence of repetitive elements. Within this region at least five copies of the suffix element were detected, as well as several putatively novel mobile elements. A number of mutations obtained from the unstable ct MR2 strain and its derivatives were mapped within the cut locus. Comparison between parental and daughter strains indicates that frequently two or more independent transposition events involving the cut locus occur simultaneously within a single germ cell, thus providing a molecular basis for the transposition explosion phenomenon.
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  • 25
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    Molecular genetics and genomics 219 (1989), S. 397-403 
    ISSN: 1617-4623
    Keywords: Drosophila ; Pyrimidine biosynthesis ; Dihydroorotate dehydrogenase ; Molecular mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The dhod locus encodes dihydroorotate dehydrogenase, the fourth enzymatic step of de novo pyrimidine biosynthesis. This locus was cloned previously by a chromosome walk in cytogenetic region 85A. The location of dhod within 85A DNA has been determined by mapping two rearrangement mutations to a small DNA region. A nearly full-length cDNA clone of the dhod transcript was isolated and partially sequenced, to confirm its identity. The cDNA clone was also used to map the transcribed DNA. A 1.5 kb dhod RNA is described which is most abundant in embryos and displays minor length heterogeneity in pupae and adults. The developmental expression of this transcript is discussed relative to the expression of dihydroorotate dehydrogenase activity and other genes of the pyrimidine biosynthetic pathway.
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    Molecular genetics and genomics 215 (1989), S. 190-199 
    ISSN: 1617-4623
    Keywords: Mutagen sensitivity ; Recombination ; Gene structure ; Drosophila ; mei-41
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    Topics: Biology
    Notes: Summary The mutagen-sensitive mutant mus(1)104 D1 of Drosophila melanogaster maps to a position on the X chromosome very close to the meiotic mutant mei-41 D5 . Both mutants have been characterized as mutagen-sensitive and defective in post-replication repair. In the present report we show by complementation studies that mus(1)104 and mus(1)103 are allelic with mei-41. In addition, two reported alleles of mus(1)104 lie between the mei-41 alleles A10 and D5. The size of the mei-41 locus is estimated to be about 0.1 centimorgans (cM). Because several alleles of mei-41 have been shown to reduce recombination and increase meiotic chromosome loss and nondisjunction, mus(1)104 D1 females were examined for defects in meiosis. Although there was no evidence for reduced recombination on the second chromosome in homozygous mus(1)104 D1 females, heterozygous mus(1)104 D1 /mei-41 〉D5 and mus(1)104 D1 /deficiency females showed reduced levels of recombination. However, there was no evidence of an increase in nondijunction in these females.
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    Molecular genetics and genomics 215 (1989), S. 257-265 
    ISSN: 1617-4623
    Keywords: Drosophila ; Maternal effect ; Syngamy ; Embryonic development ; Molecular cloning
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    Topics: Biology
    Notes: Summary The maternal effect locus fs(1) Ya is required for the fusion of the apposed sperm and egg pronuclei (syngamy) following fertilization in Drosophila. It is tightly linked to another complementation group, fs(1) Yb, needed for both oogenesis and embryogenesis. We have isolated a set of overlapping cloned sequences in the 3B4-6 region of the X chromosome encompassing the fs(1) Ya-fs(1) Yb region. A single 2.4 kb maternal transcript is encoded with-in this region, and an 8.5 kb DNA fragment that contains this transcript complements both fs(1) Ya and fs(1) Yb mutations. Northern and in situ hybridization analyses show that the maternal transcript is only present in nurse cells and oocytes beginning in previtellogenic stages, and is evenly distributed in the cytoplasm of 0–2 h syncytial embryos. The transcript is not detected in later stages of embryonic development. This expression pattern correlates closely with the genetic and developmental characteristics expected of the fs(1) Ya gene product.
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    Molecular genetics and genomics 215 (1989), S. 469-477 
    ISSN: 1617-4623
    Keywords: Drosophila ; Y chromosome ; Repetitive DNA ; Testis RNA ; Transposable elements
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    Topics: Biology
    Notes: Summary A cDNA clone bank was constructed from testis poly(A)+ RNA of Drosophila hydei and screened for clones which hybridize to Y chromosomal DNA sequences. The insert of clone cDhT14 hybridizes to a family of repeated DNA sequences with members distributed within the Y chromosome and elsewhere in the genome. This type of sequence has earlier been described as the Y-associated class of DNA. Southern blot analysis of DNA from different wild-type strains of D. hydei suggests that members of the T14 family of repeated DNA sequences are parts of a family of transposable elements. The genomic localization of the T14 family of repeated DNA sequences was revealed by in situ hybridization to metaphase and polytene chromosomes, and to transcripts of Y chromosomal lampbrush loops. Approximately 10–15 members (20%–30%) of the T14 sequence family reside in 8.3 kb PstI restriction fragments. A genomic clone of one of these DNA fragments, DhT14-8.3, hybridizes to transcripts on the Y chromosomal lampbrush loop “cones”, and in conventional in situ hybridization experments to region 12D/13A of the X chromosome and to region 112 of chromosome 5. The cDNA clone cDhT14 represents a part of an abundant testis RNA species of 5.0 kb. This RNA is also present in ovaries and in 0–3 h, 3–6 h and 6–12 h embryos, but less abundantly than in testes. Both the Y chromosomal site of the 8.3 kb PstI fragments and sites elsewhere in the genome are actively transcribed. At least one of the latter genomic sites is transcribed into the 5.0 kb RNA species. This poly(A)+ RNA is present in the cytoplasm of primary spermatocytes as shown by transcript in situ hybridization. The potential function of transcripts from Y chromosomal lampbrush loops is discussed.
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    Journal of comparative physiology 159 (1989), S. 237-242 
    ISSN: 1432-136X
    Keywords: Amylase ; Mosquitofish ; Rat ; Drosophila ; Structure ; Function
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    Topics: Biology , Medicine
    Notes: Summary Amylases from the mosquitofish (Gambusia affinis holbrooki, Pisces: Poeciliidae) and rat were purified and compared withDrosophila amylases in terms of structure and function. At the structural level, amino acid compositions of the three amylases were compared. At the functional level, amylase activities were compared on various substrates and in the presence of inhibitors. While the amylases from all three organisms had properties typical of alpha-amylases, both structural and functional differences were observed. Using resemblance coefficients of distance and similarity from numerical taxonomy, it was determined that the amylases from the rat andDrosophila were more similar to each other than either was to amylase from the mosquitofish, and that structural differences between the amylases did not reflect functional differences, i.e. there was no correlation between amylase structural and functional distances.
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    Chromatographia 27 (1989), S. 552-558 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Radio gas chromatography ; 3H- and14C-labelled compounds ; Isotope effects
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    Topics: Chemistry and Pharmacology
    Notes: Summary Radio gas chromatography (RGC) is a valuable tool for the analysis of radioactively labelled compounds. Recent advances in capillary GC, especially in column technology and instrumentation have also induced new possibilities in this field. With regard to the preservation of the achieved separation efficiency, radioactivity detection is the main problem in capillary RGC. Based on published data and on our extensive experience in conventional RGC, a simple, reliable and versatile method has been developed for the radioactive detection: purge gas is added to the effluent of the capillary column and the RGC detection unit with conversion tube and flow-through proportional counter is used maintaining small dead volumes and dimensions. The influence of the extra-column volumes and of the total gas flow rate (of the carrier, purge and quenching gases) on the peak shape was investigated. It was also found that the isotopic effect commonly known in GC of2H- and3H-labelled compounds is hardly measurable for larger [G-14C] labelled species such as [G-14C] labelled higher fatty acids with high isotopic abundance of14C, even on the highly efficient capillary columns. The quantitative aspects of the detection method used are discussed and some applications to the analysis of labelled biochemicals (amino and fatty acids) are demonstrated.
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    Chromatographia 27 (1989), S. 644-648 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ion exchange resins ; Polymeric supports ; Chloromethanes
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    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of compounds of various classes on macroporous sulfonated cation exchangers in the form of the fourth period elements in Mendeleev's table (i. e. in the K, Ca, Co, Ni, Cu, Zn-forms) has been investigated. It has been shown that these sorbents are characterized by a high specificity of molecular interaction. It has also been established that the gas-chromatographic properties of cation exchangers depend on the nature and valency of the metal ion in the ionogenic group.
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    Chromatographia 27 (1989), S. 109-112 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Packed columns ; Immobilized stationary phase ; Poly(ethylene glycol) phase
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    Topics: Chemistry and Pharmacology
    Notes: Summary Carbowax 20M poly(ethylene glycol) stationary phase was immobilized on Chromosorb W by cross-linking with pluriisocyanate. The properties of the prepared packing material were investigated. Column efficiencies of 10,960 and 7,510 theoretical plates/meter were obtained for n-pentadecane and 1-heptanol, respectively.
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    Chromatographia 27 (1989), S. 159-163 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Flame photometric detector ; Sulfur compounds ; Response quenching
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    Topics: Chemistry and Pharmacology
    Notes: Summary The long time retardation of the main hydrocarbon peak in the chimney of the flame photometric detector greatly reduces the responses of later-eluting sulfur compounds. In the absence of hydrocarbons in the flame, the slope (s) of the log I vs. log [S] plot (where I is the sulfur response and [S] is the sulfur concentration in the sample) is of the highest value and is constant for all experimental conditions tested. Flame hydrocarbons cause the s value to decrease, and this is dependent on the oxygen to hydrogen ratio in the flame (O/H) and, under certain conditions, also on the sulfur to carbon ratio (S/C) of the sample. The abnormalities observed in the determination of methyl thiol in natural gas are explained on the basis of the present study.
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    Chromatographia 27 (1989), S. 631-632 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Wide-bore glass capillary columns ; End-sealing ; Static coating
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    Topics: Chemistry and Pharmacology
    Notes: Summary An end-sealing method to be used for static coating of wide-bore glass capillaries is described. After the capillary was completely filled with the coating solution, one end is connected to a gas-tight syringe (10-ml volume) via silicone tubing and the other end is fixed with shortcutted silicone tubing for sealing with a plug. The method is highly successful.
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  • 35
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ethyl carbamate ; Direct injection quantification ; Cold injection system ; Optimised SIM
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    Topics: Chemistry and Pharmacology
    Notes: Summary An integrated procedure is described which allows direct injection quantitative screening to single figure parts per billion (μg/L) levels of ethyl carbamate in the natural matrix of distilled alcoholic beverage. Injection and detection performance was studied and optimized to allow this routine, reproducible, trace analysis without any sample pre-treatment. All aspects of the analysis including autosampler run sequences and automated internal standard report generation are initiated and controlled from a single GC/MS workstation.
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    Chromatographia 27 (1989), S. 455-460 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Surface free energy ; Silane-covered materials ; Film pressure
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    Topics: Chemistry and Pharmacology
    Notes: Summary The surface free energy, or film pressure, π0, is measured for mica (Mica HK), silane-covered mica (Mica NP), Chromosorb W DMCS and glass beads. The film pressure is obtained from gas chromatography. The materials are used as adsorbents and benzyl alcohol and n-dodecane are used as molecular probes. Adsorption isotherms at 353 K are obtained from gas chromatography data and the surface free energy is computed with the help of the Gibbs equation. Values of π0 for a given surface are found to vary with the molecular probe. With benzyl alcohol π0 varies from 44 erg/cm2 for Mica 60 HK to 76 erg/cm2 for glass. In the case of n-dodecane π0 is found to vary in the same manner but the values range from 25 to 45 erg/cm2. The results are in good agreement with the values obtained with the contact angle method.
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    Chromatographia 27 (1989), S. 469-471 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace analysis ; Ethylene oxide ; Capillary column
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    Topics: Chemistry and Pharmacology
    Notes: Summary A headspace gas chromatographic method for determination of traces of ethylene oxide (EO) in sterilized materials has been developed. The method allows the determination of the amount of EO by putting the samples directly into acetonitrile and analysing by means of headspace GC. The procedure described is simple, sensitive, reproducible and linear. The lower limit of detection is 0.015 μg/g of sterilized material.
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    Chromatographia 28 (1989), S. 24-26 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Anesthetics ; Pharmacokinetics
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    Topics: Chemistry and Pharmacology
    Notes: Summary A sensitive capillary gas chromatographic method is described for the simultaneous determination of lidocaine, tetracaine, procaine and dibucaine. The method was applied to the determination of anesthetics in tissue homogenates incubated at 38°C at doses between 10 and 400 mg/kg. In the liver tissue thein vitro metabolization of the studied anesthetics is most rapid for tetracaine, also fast for procaine, while for lidocaine and dibucaine the metabolization is very slow. In brain tissue thein vitro metabolization of anesthetics is very slow. The method shows good analytical parameters: linearity between 5 and 40 μg/ml; day-to-day reproducibility ca. 8% for a concentration of 20 μg/ml, precision ca. 7% for a concentration of 20μg/ml. Accuracy is also very good.
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    Chromatographia 28 (1989), S. 639-642 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Split injection ; Sample tailing and cold trap effects
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    Topics: Chemistry and Pharmacology
    Notes: Summary Sample plug tailing together with a cold trap effect brings about discrimination against low boiling components at an initial column temperature above the boiling point of the solvent. In conventional split injection, this compensates for the opposite effects of such factors as the gas phase viscocity change and the pressure wave during the split period, and reasonable results are obtained. In stop-flow injection, however, since the influences of the opposite factors are diminished, the sample plug tailing and the cold trap effect may produce results showing lower than true concentrations for the low boiling components.
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    Chromatographia 28 (1989), S. 313-314 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Fused-silica columns ; Static coating ; Sealing method
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    Topics: Chemistry and Pharmacology
    Notes: Summary In this paper a new sealing method for the static coating of capillary columns is described. When one end of the fully filled capillary was immersed into liquid nitrogen in a Dewar flask, the coating solution at this end would be frozen and became a temporary seal, and an air-free solvent/seal interface was obtained. No bumping has ever been found at the interface, even when butane was used as solvent. By applying this sealing method, several capillary columns, including some narrow bore capillary, had been successfully coated.
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    Chromatographia 28 (1989), S. 502-504 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention variation ; Effect of sample composition on retention
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    Topics: Chemistry and Pharmacology
    Notes: Summary The variation of the retention index of a solute due to the presence of a closely neighboring peak is discussed. The neighboring peak is likely to modify the original stationary liquid by forming a temporary “mixed” stationary phase. The extent of the retention index variation is influenced by many experimental parameters and becomes pronounced when the stationary phase is overloaded by the neighboring peak and the film thickness of the stationary phase is not very large. However, the exact extent of this variation is rather unpredictable. The practical significance of this finding is also discussed.
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  • 42
    ISSN: 1612-1112
    Keywords: Gas chromatography ; FAME fingerprinting ; Animal fats ; Transesterification
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    Topics: Chemistry and Pharmacology
    Notes: Summary The triglycerides of animal fats from milk, meat or cheese can also be characterized by the gaschromatographic pattern of the fatty acid methylesters (FAME) after conversion by an unsophisticated transesterification procedure. Even from the FAME pattern falsifications of commercial animal fats can be revealed by the fast separation of the FAME using a standard CW 20 M (polyethyleneglycol) capillary column. Characteristic patterns of FAME originating from different animals are shown. The patterns of the FAME from different races of the same animal are very similar, so that the characterisation according to the type of animal is not disturbed.
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    Chromatographia 27 (1989), S. 71-76 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Electron-capture detector ; Constant-current mode ECD ; Non-linearity of ECD
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    Topics: Chemistry and Pharmacology
    Notes: Summary The effects of the ionization source activity, sample input rate, electron capture rate constant, ventilation rate constant and baseline frequency on the linearity, detectability and sensitivity of the constant-current electron-capture detector (CC-ECD) were investigated. The proposed model representing an extension of the Wenthworth-Lovelock model proved to be useful in demonstrating that the CC-ECD can be highly nonlinear for strong electron capturers, at high ionization source activities, at a low ventilation rate constant and at low baseline frequencies. Optimization of the CC-ECD operation is possible by a reasonable adjustment of the studied parameters.
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  • 44
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Coke oven gas evolution ; On-line gas analysis
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    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatograph will thermal conductivity detector (TCD) connected on line via a cleaning train to the semi-industrial scale Coke Oven Text Plant of the Spanish National Coal Institute (INCAR), has been used to control the evolution of the permanent gases during the coking process. The undesirable presence of oxygen in the coke oven gas can be detected with this system that will be applied to determine the end of the coking process by quantitative analysis of the gas evolved.
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    Chromatographia 27 (1989), S. 182-184 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Micropacked columns ; Alkyl-modified silica ; Hydrocarbons
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    Topics: Chemistry and Pharmacology
    Notes: Summary Micropacked columns for liquid chromatography were evaluated for the gas chromatographic separation of hydrocarbons. A glass-lined stainless-steel tube of 30 cm×0.3 mm i.d., packed with 5-μm alkyl-modified silica, was employed as the separation column. The micropacked columns were successfully applied to the separation of components of a light oil and a kerosine.
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    Chromatographia 27 (1989), S. 205-208 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Kováts indices ; Numerical interpolation ; Dead time
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    Topics: Chemistry and Pharmacology
    Notes: Summary Comparison with normal procedures shows that numerical interpolation of the logarithms of gross retention times generates quite useful Kováts indices for gas chromatographic analysis. The dead time concept is not used in the interpolation.
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  • 47
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Adsorption studies ; Clinoptilolite ; Zeolite
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    Topics: Chemistry and Pharmacology
    Notes: Summary Adsorption properties of NH4-clinoptilolite, thermally treated at 400, 550 and 650°C, were investigated by gas-solid chromatography. Adsorption of ten hydrocarbons, including aliphatic, alicyclic, chlorinated and aromatic compounds is discussed in the light of adsorbate-adsorbent interactions. The imporatant thermodynamic parameters of adsorption are determined. A detailed discussion is presented on the alteration of the surface properties of NH4-clinoptilolite caused by thermal treatment. Experimental data obtained show that NH4-clinoptilolite treated at 650°C can be successfully employed as a column packing in analytical gassolid chromatography.
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    Chromatographia 27 (1989), S. 436-440 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid crystal stationary phases ; PAH ; FAME ; Mesomorphic polysiloxane phases
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    Topics: Chemistry and Pharmacology
    Notes: Summary The gas-chromatographic properties of two mesomorphic polysiloxane (MEPSIL) stationary phases, one smectic (SB) and the other nematic (N), were investigated. The retention indices and separation factors (relative retentions), α, of several pairs of polycyclic aromatic hydrocarbon (PAH) and fatty acid methyl ester (FAME) isomer solutes were used to gauge differences in the selectivity provided by each. The heats of solution of the PAH showed that the smectic MEPSIL is more selective for solutes with different length-to-breadth ratios. Also, five peaks were resolved for sixcis andtrans octadecenoic FAME isomers with this solvent. The nematic MEPSIL, on the other hand, was found to be more useful at higher temperatures because of its higher clearing point. In addition, solute capacity factors were smaller than those observed with the smectic MEPSIL, as evidenced by lower retention indices. The former was therefore more useful for the analysis of high molecular-weight PAH.
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  • 49
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Colloidal stationary phases ; Liquid crystals as stationary phases
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    Notes: Summary Colloid systems consisting of the nematic liquid crystals p,p′-azoxyphenetol and p,p′-methoxyethoxyazoxybenzene and high-disperse mineral particles (aerosil, carbon black) are proposed to be used as stationary phases in gas chromatography. The dependence of the retention of normal paraffins, Rohrschneider and McReynolds test solutes (benzene, ethanol, methyl ethyl ketone, nitromethane, pyridine, butanol-1, 2-pentanone, and nitropropane) on the composition of the colloid systems was investigated. The investigated colloid sorbents including liquid crystals retain their selectivity for meta/para isomers up to 50% of the aerosil content and practically at all studied carbon black concentrations.
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  • 50
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Chlorinated methanes ; Activated charcoal sampling ; Pollution
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    Topics: Chemistry and Pharmacology
    Notes: Summary A sampling method using activated charcoal, followed by percolation with ethanol and FID or ECD chromatographic analysis, depending on the concentrations to be monitored, makes it possible to evaluate concentrations of methylene chloride between 5 and 1000mg m−3, chloroform between 0.1 and 2000mg m−3, and carbon tetrachloride between 0.015 and 1000mg m−3.
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    Chromatographia 28 (1989), S. 139-142 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Silica surface ; Silanols ; Strongly interacting sites
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    Topics: Chemistry and Pharmacology
    Notes: Summary The paper describes how the method of gas-phase titration of the strongest adsorption sites can be utilized to calculate a relative strength of interaction of the sites with chromatographic solutes. An excellent correlation with earlier, theoretical predictions of Giddings is noted. Significant influence of the sites on the width of a chromatographic band is observed when the interactions are an order of magnitude stronger than those of normal sites.
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    Chromatographia 28 (1989), S. 167-169 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Determination of monomer in polymers ; Sealed glass capillary sampling
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    Topics: Chemistry and Pharmacology
    Notes: Summary Residual styrene in polystyrene and free phenol in phenolic plywood adhesive have been determined by sealing samples in glass capillary tubes. To prevent loss of sample the ends of the capillary tubes were sealed with a kind of putty made of anhydrous calcium sulfare, calcium carbonate and a small quantity of phenylmethylsilicone fluid. No volatile compounds were released from this sealing material when the capillary tubes were placed in a quartz vaporising furnace at temperatures up to 300°C.
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  • 53
    ISSN: 1612-1112
    Keywords: Gas chromatography ; GC/MS and headspace GC ; Elastomeric stoppers for injectables ; Trace hydrocarbons
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    Topics: Chemistry and Pharmacology
    Notes: Summary Elastomeric stoppers for injectables have been surveyed by means of GC/MS screening. Residual contamination by hexanes (2-methylpentane, 3-methylpentane, n-hexane, methylcyclopentane, cyclohexane) toluene and xylenes occurred in all the samples tested. A headspace GC purity test is suggested, by using these residual chemicals as purity indexes.
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  • 54
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Optimization of gas-solid separations ; Plate height equation ; Computer mapping procedure
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    Topics: Chemistry and Pharmacology
    Notes: Summary This paper proposes an optimization model for gas-solid chromatographic separations in a non-linear programming form and an approximate equation of the plate height for the model. A computer-modified mapping procedure is also described for searching the optimum separation conditions. Just five experiments and about 20 minutes of the computer time are needed to establish the optima of column temperature and of the carrier gas linear velocity. The relative deviation between the predicted and the experimental values was found to be within 20% for the plate heights, and within 1.5% for the retention times.
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  • 55
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Renewal theory ; Monte-Carlo simulation ; Prediction of retention and peak widths
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    Notes: Summary A new method for prediction of gas chromatographic retention times and peak half widths is based on the renewal theory. The only requirements are the heats of vaporization of the compounds to be separated and one calibration measurement. With this data, retention times and peak half widths can be predicted for isothermal as well as temperature-programmed gas chromatography. For the separation of non-polar substances on non-polar stationary phases the prediction error for retention times is approx. 1–2%. First simulations of polar molecules and polar stationary phases indicate that this method is also applicable in these cases but some extension will be required.
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  • 56
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Microwave plasma detector ; Thiophenes ; Shale oil distillates
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    Topics: Chemistry and Pharmacology
    Notes: Summary A series of alkylthiophenes and dimethyl disulfide were tentatively identified in an oil shale retort gas condensate from a 6-kg bench-scale retort using gas chromatography with a microwave-induced helium plasma detector (GC-MIP). The sulfur species were present in concentrations ranging from 1.5 to 10.7 mol ppm in the undiluted offgas. The GC-MIP technique was successful in selectively detecting the sulfur components in the complex mixture. Quantitation was simplified relative to GC with flame-photometric detection because of the absence of quenching or other interference problems at the concentrations studied. Attempts to determine stoichiometry of the sulfur components by comparison of carbon, hydrogen, and sulfur ratios with those of standards were unsuccessful because of the complexity of the carbon and hydrogen chromatograms.
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  • 57
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Air pollutants ; Adsorbent enrichment ; Thermal desorption
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    Topics: Chemistry and Pharmacology
    Notes: Summary A new automatic method is described for quantitative determination of some light C2–C4 hydrocarbons in urban air: ethene, ethyne, propane, propene, butane and iso-butane. This method is based on an enrichment step at room temperature using a solid sorbent and subsequent thermal desorption for gas chromatographic separation and FID detection. The instrument is built up of a small commercial gas chromatograph and a laboratory-made trap and desorption unit. The sampling parameters, sample volume, concentration and humidity of air have been investigated.
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  • 58
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    Chromatographia 27 (1989), S. 596-600 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Mass spectrometry ; Azines
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    Topics: Chemistry and Pharmacology
    Notes: Summary We have studied the gas chromatographic behaviour of several 3-methyl-2-benzothiazolone-azines. In HPLC analysis all the unsymmetrical azines show double peaks, whereas in HRGC analysis only some of these compounds show the two peaks corresponding to the Z (syn) and E (anti) isomers. By means GC/MS analysis the mass spectrum of each azine was recorded. We have assigned the E and Z configurations to the first and second gas chromtographic peaks on the basis of the ratio between the relative abundances of the two most significant framment ions at m/z 163 and 164.
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  • 59
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    Chromatographia 27 (1989), S. 221-224 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Large volume sample injection ; Closed on-column injector
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    Topics: Chemistry and Pharmacology
    Notes: Summary A new simplified version of a “closed” on-column injector is introduced. Because of its design isobaric injection conditions do not have to be followed and a wide range of injection temperatures above the boiling point of the sample solvent can be chosen for on-column injections in capillary gas chromatography. Also, when following certain basic injection rules, injections of large sample volumes (≥20 μl or more) give accurate and reproducible results without further problems.
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  • 60
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    Chromatographia 27 (1989), S. 233-237 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; FTIR ; Hemoglobin
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    Topics: Chemistry and Pharmacology
    Notes: Summary The use of N, O (S)-tert.-Butyldimethylsilyl derivatives of amino acids for capillary gas chromatography and FTIR identification of amino acids is described. Rapid identification is achieved by computerised comparison of FTIR spectra. Derivatives that are characterised by identical sets of ions in gas chromatography-mass spectrometry experiments are clearly distinguished and identified by means of their infrared spectra. This, for example, is the case with alanine, β-alanine and sarcosine, which norvaline and valine, and with norleucine, leucine and isoleucine. Unknows are also promptly detected. This is especially useful in screening biological samples for less common amino acids. Screening of hemoglogin hydrolysates for amino acid adducts is exemplified.
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  • 61
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Trichloroethyl ester ; Dicarboxylic acid ; Urine samples ; Electron capture ; Biological monitoring
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    Topics: Chemistry and Pharmacology
    Notes: Summary Dicarboxylic acids were esterified by 2,2,2-trichloroethanol by using trifluoroacetic anhydride and phosphoric acid as catalysts. The method was developed to facilitate the evaluation of workers' exposure to sensitising acid anhydrides and other compounds metabolised to acids in the body. The sensitivity of the acid determination in urine was in the order of 2–4 ng ml−1 for aliphatic and alicyclic acids and 15ng ml−1 for phthalic acid.
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  • 62
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    Chromatographia 27 (1989), S. 499-508 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Electron capture detector ; Space-charge model
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    Topics: Chemistry and Pharmacology
    Notes: Summary Mathematical analysis, allowing the determination of the distribution of the electron and positive ion concentration in an electron-capture detector with a cylindrical electrode arrangement and with constant and pulsed voltage supplies, has been carried out. The measurements obtained confirm the assumptions concerning the “space change” model of the ECD introduced by Gobby et al. and cast doubt upon the general assumption of the complete removal of the electrons from the detector by the voltage pulse. The physical factors influencing the current characteristics of the detector and the possible distortions connected with the electrode geometry have been explained on the basis of the measurements carried out.
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  • 63
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    Chromatographia 27 (1989), S. 333-339 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Catalytic reactions ; Adsorption and desorption rate constants ; Reversed-flow techniques
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    Topics: Chemistry and Pharmacology
    Notes: Summary A small volume of reactant, 1-butene, is injected onto a catalytic bed and is allowed to diffuse away from it together with the product butane, along a narrow empty chromatographic tube; the latter is connected perpendicularly to the middle point of another similar tube through which hydrogen flows as reactant and carrier gas, transferring both 1-butene and butane to the detector through an analytical column. By using the reversed-flow GC technique, extra peaks are obtained in the chromatographic trace, sampling the concentration of both the readtant and product at the junction of the two tubes as a function of time. These concentrations are the result of the diffusion of the substances along the narrow empty tube, modified by the adsorption-desorption rates and the rate of the catalytic reaction. From the extra peaks of the reactant and product, a number of physicochemical quantities pertaining to the catalytic reaction can be calculated simultaneously, using appropriate mathematical analysis. These include adsorption rate constants, reaction rate constants, desorption rate constants, partition coefficients, and the overall mass transfer coefficients of the reactant across the gas-solid boundary of the catalytic bed.
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  • 64
    ISSN: 1612-1112
    Keywords: Gas chromatography ; KF·2H2O as stationary phase ; Alcohols ; Organic bases
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    Topics: Chemistry and Pharmacology
    Notes: Summary Potassium fluoride crystal dihydrate is used as the stationary phase for the rapid analysis of polar compounds in aqueous solutions. KF·2H2O is compared with some conventional stationary phases, organic salts and molten crystal hydrates of inorganic salts.
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  • 65
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    Chromatographia 28 (1989), S. 237-240 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Slope of log plot ; Homologous series ; Retention index ; Retention time ; Uncertainty ; Free energy
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    Topics: Chemistry and Pharmacology
    Notes: Summary The free energy of partition of a methylene group $$\Delta G_{CH_2 }^ \circ $$ is constant within a homologous series down to C5 and nearly constant to C3, contrary to the finding of Golovnya and Grigoryeva [5]. Retention indices are linear with carbon number: values may be extrapolated from higher carbon numbers to C5 within experimental uncertainty, to C4 with error no greater than 5 units and to C3 with error no greater than 10 units. Error in extrapolating the logarithm of the adjusted retention time, log t′R, to C5 is thus negligible, to C4 has possible error up to 5b/100 and to C3 up to 10b/100, whereb is the slope of the plot of log t′R against carbon number.
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  • 66
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    Chromatographia 28 (1989), S. 631-638 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace GC/FTIR ; Optimization ; Detection limits ; Cryogenic trapping
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    Topics: Chemistry and Pharmacology
    Notes: Summary For the trace analysis of volatile components in a nonvolatile matrix, the headspace sampling technique offers the potential to lower detection limits in GC/FTIR experiments. Optimization of chromatographic operating parameters for Headspace GC/FTIR is discussed, aiming at the best compromise between maximum chromatographic resolution and highest S/N ratio of the infrared spectra. It is shown that the combination of headspace sampling with cryogenic capillary head trapping is able to provide Headspace GC/FTIR with the best performance in terms of sensitivity and chromatographic resolution.
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  • 67
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Reaction rate studies ; Dicyclopentadiene
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    Topics: Chemistry and Pharmacology
    Notes: Summary The gas chromatographic reactor technique was used to study the kinetics of dicyclopentadiene dissociation in several liquid phases (Versamid 900, neopentyl glycol sebacate, Triton X-305, Carbowax 6000, ethylene glycol phthalate and diethylene glycol succinate). Reaction rates and Arrhenius parameters are reported in the temperature range of 170–200°C. Kinetic data for the lower polarity liquid phases are in good agreement with literature values for liquid phases of the same nature reported previously. Reaction rates are higher when polar liquid phases are used. This behavior can be explained as a result of side reactions which lead to high molecular weight compounds which can be observed in the reaction chromatogram.
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    Chromatographia 28 (1989), S. 385-390 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary column ; Split injection ; Stop-flow method
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    Topics: Chemistry and Pharmacology
    Notes: Summary Major concerns in the development of the stop-flow split injection are discussed. Split ratio fluctuation caused by the pressure wave, solvent recondensation and gas viscosity change can be substantially diminished through the formation of a nearly uniform gaseous sample plug. Instrumental variables exerting influence on the accuracy of quantitation were studied. Higher injector temperature and the use of a carrier gas with higher heat conductivity benefit the quick vaporization of the sample liquid, and thus, help in the formation of a sample plug with more unformity.
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    Chromatographia 28 (1989), S. 405-411 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Concentration of volatile flavor compounds ; ODS packing
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    Topics: Chemistry and Pharmacology
    Notes: Summary Volatile flavor compounds in aqueous model systems, distillates of coffee extract and juices such as apple, tomato, pineapple and grape were adsorbed on an ODS column during HPLC and monitoring absorption at 280nm. The adsorbed volatile compounds were eluted with a small volume of ethanol. Volatile compounds in the eluates were concentrated 22 to 100 times those in the distillates. Recovery of compounds was 50–90%. Breakthrough of specific compounds such as γ-valerolactone, furfuryl acetate and t-2-hexenal in the model systems and several compounds in the juice distillates was detected by capillary GC. Pattern similarity calculated between the GC profiles of a juice distillate and the corresponding eluate gave a qualitative comparison. This novel and versatile method utilizing conventional RP-HPLC may be widely applicable for concentrating volatiles in aqueous systems, at levels from ppm to ppb.
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    Journal of chemical ecology 15 (1989), S. 663-676 
    ISSN: 1573-1561
    Keywords: Drosophila ; Diptera ; Drosophilidae ; triterpene glycosides ; cactus ; fitness components ; host-plant relationships
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effects of pentacyclic triterpene glycosides extracted from agria and organ pipe cacti on three fitness parameters of the cactophilic fruit fly,Drosophila mojavensis were tested. Triterpene glycosides from organ pipe increased development time and reduced larval viability while those from agria produced smaller adults (reduced fecundity). In addition, the microbial communities in the organ pipe saponin media were less dense than those in the media to which agria saponins had been added. The role of cactus triterpene glycosides in the ecology of thisDrosophila species is discussed.
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    Journal of insect behavior 1 (1988), S. 3-15 
    ISSN: 1572-8889
    Keywords: host preference ; habitat selection ; experience ; learning ; Drosophila ; host races ; population genetics
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    Topics: Biology
    Notes: Abstract A field experiment with Drosophila melanogasterrevealed that when flies encounter a particular food type soon after emergence, the probability of their subsequently being attracted to such a resource is increased. In this experiment, the length of time flies experienced their postemergence environments was under the control of the flies themselves. The experiment thus realistically mimicked one form of experiential effect that may be important in nature. A theoretical model is developed which shows that enhanced adult preferences for the types of resources fed on as larvae can substantially increase the degree of host-based genetic subdivision within a polyphagous population.
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    Entomologia experimentalis et applicata 47 (1988), S. 81-88 
    ISSN: 1570-7458
    Keywords: imaginal diapause ; male mating activity ; genetics ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les femelles de D. triauraria Bock & Wheeler (Dipt. Drosophilidae) sont connues pour présenter une diapause reproductrice aux photophases courtes. Les mâles eux aussi ont révélé une activité sexuelle réduite aux photophases courtes, c'est-à-dire qu'ils sont entrés comme les femelles en diapause reproductive. Les photophases critiques pour l'induction de la diapause des mâles et des femelles n'ont pas présenté de différences. Les diapause des mâles et des femelles s'achèvent même sous courtes photophases, mais la diapause mâle était quelque peu plus faible que la diapause femelle. La photophase critique et le taux de diapause ont varié en fonction de l'origine géographique dans l'espèce actuelle. Lors de croisements entre lignées diapausantes et non-diapausantes, la photophase critique et la durée de la diapause ont été héritées quantitativement. A partir de ces expériences et d'expériences précédentes de croisements (Kimura, 1983), quelques modèles de méchnisme d'induction de la diapause de cette espèce sont proposés.
    Notes: Abstract In Drosophila triauraria Bock & Wheeler (Diptera: Drosophilidae) of which females were known to enter reproductive diapause at short daylengths, males also showed reduced mating activity at short daylengths, i.e., males as well as females entered reproductive diapause. The critical daylength for diapause induction did not differ between females and males. Both male and female diapause ended even under short daylengths, but the male diapause was somewhat weaker than the female diapause. The critical daylength and the diapause rate varied geographically in this species. In the cross between diapausing and non-diapausing strains, the critical daylength and the diapause duration inherited in a quantitative manner. On the basis of the present and previous crossing experiments, some models are proposed on the mechanism of diapause induction of this species.
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    Journal of molecular evolution 28 (1988), S. 145-150 
    ISSN: 1432-1432
    Keywords: Alcohol dehydrogenase ; Drosophila ; Enzyme kinetics ; Product inhibition ; Microevolution
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    Topics: Biology
    Notes: Summary Because natural populations ofDrosophila melanogaster are polymorphic for different allozymes of alcohol dehydrogenase (ADH) and becauseD. melanogaster is more tolerant to the toxic effects of ethanol than its sibling speciesD. simulans, information regarding the sensitivities of the different forms of ADH to the products of ethanol degradation are of ecological importance. ADH-F, ADH-S, ADH-71k ofD. melanogaster and the ADH ofD. simulans were inhibited by NADH, but the inhibition was relieved by NAD+. The order of sensitivity of NADH was ADH-F〈ADH-71k, ADH-S〈ADH-simulans with ADH-F being about four times less sensitive than theD. melanogaster enzymes and 12 times less sensitive than theD. simulans enzyme. Acetaldehyde inhibited the ethanolto-acetaldehyde activity of the ADHs, but at low acetaldehyde concentrations ethanol and NAD+ reduced the inhibition. ADH-71k and ADH-F were more subject to the inhibitory action of acetaldehyde than ADH-S and ADH-simulans, with ADH-71k being seven times more sensitive than ADH-S. The pattern of product inhibition of ADH-71k suggests a rapid equilibrium random mechanism for ethanol oxidation. Thus, although the ADH variants only differ by a few amino acids, these differences exert a far larger impact on their intrinsic properties than previously thought. How differences in product inhibition may be of significance in the evolution of the ADHs is discussed.
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    Development genes and evolution 197 (1988), S. 19-26 
    ISSN: 1432-041X
    Keywords: Drosophila ; Morphogenesis ; Appendages
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    Topics: Biology
    Notes: Summary The phenotype of rotund (rn) null alleles is described, and compared to wild type. The mutants are expressed zygotically and cause position specific defects in certain imaginal discs (antenna, legs, wing, haltere and proboscis) and their corresponding adult derivatives. In the discs, specific folds are absent in rn mutants compared to wild type. Clonal analysis shows that the rn + gene is partially autonomous in its expression in cells destined to form certain distal parts of the adult appendages. The results are consistent with the idea that the rn + gene is required for normal morphogenesis of specific distal parts of the adult appendages.
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    Development genes and evolution 197 (1988), S. 40-48 
    ISSN: 1432-041X
    Keywords: Drosophila ; Homeosis ; Tumorous-head ; Bithorax-complex mutant ; Morphology
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    Topics: Biology
    Notes: Summary Transformations of tumorous-head Drosophila melanogaster were examined in order to investigate whether head structures were replaced by specific abdominal structures. Heads selected for the presence of genital structures were analyzed in detail. Female abnormalities included any combination of vaginal teeth, vulvar papillae, sensilla trichodea, abdominal tergites 6 (T6), 7 (T7), 8 (T8) and anal plate. Anal plate was observed in the prefrons and rostral membrane, while all other genital structures were intimately associated with modified shingle cuticle. Male abnormalities included transformation of antennal structures to penis, clasper teeth, lateral plate, anal plate and eye to T6. The distribution of each type of homeotic structure was confined to general regions of the eye-antenna, with no precise dividing lines between them. However, the spatial sequence of homeotic structures in the eye-antenna was generally the same as the sequence of the same structures in the posterior abdomen.
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    Development genes and evolution 197 (1988), S. 457-470 
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Neurogenic genes ; Achaetescute complex ; Daughterless ; Genetic interactions ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Drosophila melanogaster the neuroblasts separate from epidermoblasts to give rise to the neural primordium. This process is under the control of several genes. The group of the so-called neurogenic genes is required for epidermal development; other genes, comprising those of the achaete-scute complex and daughterless, are required for neural development. We have studied the relationships between both groups of genes in two different ways. We have analyzed the phenotype of double-mutant embryos and our results show that the neural hyperplasia caused by neurogenic mutations can be partially prevented if a mutation in one of the other genes is present in the same genome. Only the neural cells that do not require the function of a particular gene of the achaete-scute complex in the wild-type seem to develop to a neural fate in the double mutant embryos. At least some of the genetic interactions affect the transcriptional level, as shown by in situ hybridization, since the territories of transcription of the achaetescute genes are expanded in neurogenic mutants. All cells of the neurogenic region of the double mutants apparently initiate neural development. However, during later development some of these cells switch their fate either to epidermogenesis or to cell death and this leads to the final phenotype of the double mutants. We discuss these results with respect to the events of early neurogenesis.
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  • 77
    ISSN: 1432-041X
    Keywords: Drosophila ; shibire ; Neuronal development ; Muscle ; Giant fiber pathway
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    Topics: Biology
    Notes: Summary The temperature-sensitive mutation shibire (shi) in Drosophila melanogaster is thought to disrupt membrane recycling processes, including endocytotic vesicle pinch-off. This mutation can perturb the development of nerves and muscles of the adult escape response. After exposure to a heat pulse (6 h at 30° C) at 20 h of pupal development, adults have abnormal flight muscles. Wing depressor muscles (DLM) are reduced in number from the normal six to one or two fibers, and are composed of enlarged fibers that appear to represent fiber fusion; large spaces devoid of muscle fibers suggested fiber deletion. The normal five motor axons are present in the peripheral nerve PDMN near the ganglion. However, while some motor axons pass dorsally to the extant fibers, other motor axons lacking end targets pass into an abnormal posterior branch and terminate in a neuroma, i.e., a tangle of axons and glia without muscle target tissue. Hemisynapses are common in axons of the proximal PDMN and within the neuroma, but they are rarely seen in control (no heat pulse) shi or wild-type flies. All surviving muscle fibers are innervated; no muscle tissue exists without innervation. Fibrillar fine structure and neuromuscular synapses appear normal. Fused fibers have dual innervation, suggesting correct and specific matching of target tissue and motor axons. Motor axons lacking target fibers do not innervate erroneous targets but instead terminate in the neuroma. These results suggest developmental constraints and rules, which may contribute to the orderly, stereotyped development in the normal flight system. The nature of the anomalies inducible in the flight motor system in shi flies implies that membrane recycling events at about 20 h of pupal development are critical to the formation of the normal adult nerve-muscle pattern for DLM flight muscles.
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  • 78
    ISSN: 1432-041X
    Keywords: Cell interactions ; Cell commitment ; Neurogenesis ; Drosophila
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    Topics: Biology
    Notes: Summary Cell-cell interactions are involved in mediating developmental fate. An example is the decision of the neuroectodermal cells of Drosophila to develop as neural or epidermal progenitors, where cellular interactions participate in the process of acquisition of either cell fate. The results of heterochronic cell transplantations we describe here suggest that both neuroblasts and epidermoblasts are not irreversibly committed to a particular developmental fate. Rather, they retain the ability to interact with neighbouring cells and, under our experimental conditions, are capable of switching their fate during a relatively long period of time, i.e. until the end of embryonic stage 11.
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    Development genes and evolution 197 (1988), S. 435-440 
    ISSN: 1432-041X
    Keywords: Drosophila ; Homoeotic genes ; Segment differentiation
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    Topics: Biology
    Notes: Summary Regulator of bithorax (Rg-bx)−, or trithorax (trx)− lethal larvae occasionally show a homoeotic transformation of the dorsal prothorax to mesothoracic structures. This transformation suggests a reduced activity of the Sex combs reduced (Scr) gene on the basis of gene dosage studies, as well as enhanced expression of the phenotypes of the weak Scr − alleles in Rg-bx − larvae. Morphological observations of adult flies doubly heterozygous for Rg-bx and Scr mutations also suggest the enhancement of an aspect of Scr adult phenotypes. I conclude that the Rg-bx + gene function is required for the optimal expression of the Scr gene in larval and imaginai cells.
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    Development genes and evolution 197 (1988), S. 507-512 
    ISSN: 1432-041X
    Keywords: Drosophila ; Reporter gene ; hairy ; Segmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Random insertions of a promotor fused to a reporter gene, such as Lac-Z, reveal regulatory sequences that confer temporal and spatial patterns of gene expression in eukaryotes. These patterns may reflect the activity of a neighbouring gene and thus lead to the isolation of new genes essential for normal development. Here, we demonstrate that this hypothesis is true for an insertion into the well characterized segmentation gene, hairy, in Drosophila. The insertion is homozygous lethal and fails to complement other hairy alleles, giving the phenotype described for hairy mutations. The insertion is located at 66D on the polytene chromosome map, is within 300–600 bp 5′ to the first hairy exon, and is orientated in the same sense (5′-3′) as the hairy transcription unit. Expression of β-galactosidase (β-gal), deriving from the insertion, follows closely the spatio-temporal patterns of expression of hairy gene product during embryogenesis. In addition, other sites of β-galactosidase expression are shown in the third larval instar stage and in the adult ovary. The results show that some insertions, giving restricted patterns of reporter gene expression, will reflect the temporo-spatial activity of a nearby gene.
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  • 81
    ISSN: 1432-041X
    Keywords: Drosophila ; Injection of embryo ; Daudi conditioned medium ; Rudimentary ovaries ; Mean number of ovarioles
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    Topics: Biology
    Notes: Summary Drosophila melanogaster embryos were injected before the blastoderm stage with conditioned media from several male Burkitt's lymphoma human cell lines and the Daudi cell line. Such injections do not have any effect on the male genital apparatus or on the female tract. The Daudi conditioned medium modifies the ovarian morphogenesis of the flies and the rudimentary ovaries obtained look like nymphal gonads. Moreover, they have a drastically reduced number of germ cells. The ovaries that looked functional contain numerous necrotic germ cells and the mean number of ovarioles per fly is significantly smaller than that of the controls. The abnormalities observed resemble the results of experimental and genetic lack of germ cells. They disappear at very high dilution (1×10−6).
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    Development genes and evolution 197 (1988), S. 231-238 
    ISSN: 1432-041X
    Keywords: Drosophila ; Electrical polarity ; Ovarian follicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Distribution of rhodamine-conjugated lysozyme injected into the sixteen-cell syncytium comprising the germ-line portion of theDrosophila follicle is shown to be affected by charge. Positive molecules are able to migrate through intercellular bridges from the oocyte to the nurse cells, but are unable to migrate detectably from nurse cells to the oocyte. Their negatively charged counterparts can move from the nurse cells to the oocyte, but are unable to traverse the intercellular bridges in the counter direction. This charge-dependent movement of molecules is accompanied by an electrical potential difference, focused across the nurse cell-oocyte bridges, which makes the nurse cells negatively charged to the oocyte. The addition of insect hemolymph to the physiological salt solution in which the experiments were performed resulted in only a small increase in the transmembrane resistance, but enhanced the potential difference between oocyte and nurse cells from 0.2±0.3 (SE) mV (nurse cells negative) to 2.3±0.45 (SE) mV (nurse cells negative).
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  • 83
    ISSN: 1432-041X
    Keywords: Drosophila ; Homeosis ; Epidermal development ; Embryology ; Clonal analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The complex genetic locuspolyhomeotic (ph) is a member of thePolycomb (Pc)-group of genes and as such is required for the normal expression of ANT-C and BX-C genes. It also has probably other functions since amorphicph alleles display a cell death phenotype in the ventral epidermis of 12-h-old embryos. Here it is shown that lethal alleles ofph (amorph and strong hypomorph) show transformation of most of their segments towards AB8. Theph + product is required autonomously in imaginal cells. The total lack ofph + function prevents viability of the cuticular derivatives of these cells.ph has a strong maternal effect on segmental identity and epidermal development that can not be rescued by one paternally supplied dose ofph + in the zygote. These phenotypes differ substantially from those of previously describedPc-group genes. AmongPc-group genes,ph seems to be the only one that is strongly required both maternally and zygotically for normal embryonic development.
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  • 84
    ISSN: 1432-041X
    Keywords: Drosophila ; Ultrabithorax ; Development ; Regulation ; Protein distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Most viable alleles of homeotic genes cause partial transformations within given lineages in a topographically specific fashion. We study this phenomenon as a way to understand the normal mechanisms involved in the spatial regulation of homeotic gene expression. To this end we have investigated the distribution of Ultrabithorax (Ubx) proteins in imaginai discs mutant for hypomorphic and neomorphic alleles of Ubx and alleles of trans-acting genes. We find that the morphological discontinuities observed in the adult transformations are caused by corresponding new patterns of the Ubx proteins in the imaginai anlagen. These novel patterns of Ubx proteins are understood as a consequence of a process of reinforcement-extinction of Ubx expression. The evidence suggesting that this process results from a positive feed-back loop and cell-cell interactions is discussed.
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  • 85
    ISSN: 1432-041X
    Keywords: Bithorax complex ; Drosophila ; Abdominal-B mutations ; Genetic mosaics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The phenotypic effects in imaginal hypodermal tissue of a number of Abdominal-B mutations of the bithorax complex are described. Evidence is given from complementation analysis that the phenotypic heterogeneity in both the spatial limits and the nature of the homeotic transformations produced is not an arbitrary classification of allelic differences that we find. We have used genetic mosaic analysis to support the interpretation that the Abdominal-B genetic unit can exist in a number of alternative functional states of expression during development and that individual Abdominal-B mutations may abolish some states whilst leaving others unaffected.
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  • 86
    ISSN: 1432-041X
    Keywords: Drosophila ; Segment polarity gene ; Maternal effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fused is a segmentation gene belonging to the segment-polarity class. Mutations at thefused locus are known to display pleiotropic effects, causing zygotically determined anomalies of ovaries and of some adult cuticular structures, and maternally determined embryonic segmentation defects. In order to determine the amorphic phenotype offused and to study the genetical basis of its pleiotropy, newfused alleles (18 viable and 11 lethal) were isolated. The phenotype of these mutants and of others already known are described, taking into account zygotic and maternal effects. The main results provided by this analysis are as follows. Firstly, allfused alleles show the whole complex fused phenotype, and a good correlation is observed between the strength of the wing and segmentation defects, suggesting that a single function is involved in both processes. Secondly, all embryonic and larval lethals carry deficiencies which allow us to localizefused between the 17C4 and 17D2 bands of the X-chromosome. Thirdly, the 24 viable and 2 pupal lethals examined behave as point mutants, as shown cytologically or by Southern blot analysis. However, only one of them, the pupal lethalfu mH63 was proven to carry a nullfused allele, since it displays in germ-line clones a strong maternal phenotype and a very low zygotic rescue, similar to those of the small deficiencyDf(1)fu z4. The phenotype of the amorphic mutant indicates that zygotic ezpression offused is required for normal metamorphosis, while maternal expression is necessary for a normal segmentation pattern, since a complete loss offused expression during oogenesis cannot be compensated zygotically.
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  • 87
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    Development genes and evolution 197 (1988), S. 75-91 
    ISSN: 1432-041X
    Keywords: Drosophila ; Maternal effect mutation ; Pattern formation ; Gastrulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The gastrulation defective (gd) locus is a maternally expressed gene in Drosophila required for normal differentiation of structures along the embryonic dorso-ventral axis. Cuticular defects of the offspring from females with different combinations of gd alleles comprised a phenotypic continuum. Complementation among several alleles produced normal offspring while progressively more severe mutations produced a graded loss of structures from ventral, and then lateral, blastoderm cells. The most severely affected embryos consisted entirely of structures derived from dorsal blastoderm cells. Histological examination of staged siblings from selected allelic combinations showed that internal tissues were similarly affected. The tissues observed in amorphic embryos support new, more dorsal, assignments of fate map positions for blastoderm precursors of the cephalopharyngeal apparatus, hindgut and ventral nerve cord. The loss of ventral and lateral structures did not occur through cell death and appeared to involve a change in blastoderm cell fate. A direct effect of the mutations on blastoderm cell determination, however, was insufficient to explain the development of the dorsalized embryos. Intermediate phenotypes suggested that cell interactions or movements associated with morphogenesis are required for the determination of some cell fates in the dorsoventral axis. Thus, the developmental fate of all blastoderm cells may not be fixed at the time of blastoderm formation.
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  • 88
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    Development genes and evolution 197 (1988), S. 115-123 
    ISSN: 1432-041X
    Keywords: X-Chromosome Loci ; Dominant maternal effect ; Segmentation genes ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A systematic search for X chromosome loci showing a dominant maternal interaction with the segmentation genes Krüppel, hunchback, knirps and hairy was performed using deficiencies spanning 65% of the X chromosome. No interaction with the knirps gene was observed, but five regions of the X chromosome showed a maternal dominant interaction with the Krüppel gene. Two of these regions also show a maternal dominant interaction with either hunchback (region 10A7–10A8) or hairy (region 10E1–10F3). In all of these interactions dead embryos were observed which showed the same defects as embryos homozygous for the segmentation gene tested. These results suggest that a complex repartition of maternal products necessary for subsequent segmentation may occur in the Drosophila egg.
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  • 89
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    Oecologia 75 (1988), S. 400-404 
    ISSN: 1432-1939
    Keywords: Vectoring ; Drosophila ; Cactophilic yeasts ; Dispersal ; Community structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At two locations in the Sonoran Desert, yeasts were sampled from species of Drosophila, the flies' cactus hosts, and other neighboring sources of cactophilic yeasts to determine the relation between the yeasts vectored by the fly and the yeasts found in their breeding sites. D. mojavensis, D. nigrospiracula, and D. mettleri vectored yeast assemblages significantly more similar to the yeast species found on the rot from which the flies were collected than to the yeasts found on other rots from the flies host cactus or other rotting cactus at the same site. Rots with Drosophila had fewer yeast species than those without flies, suggesting that flies were associated with younger rots. Rots with flies and the Drosophila also had more yeast species with the capability to produce ethyl acetate than rots without flies. The results support the contention that cactophilic Drosophila feed on a subset of the yeasts available in an area, and may act to maintain differences among the yeast communities found on different species of cactus.
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  • 90
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    Oecologia 75 (1988), S. 516-520 
    ISSN: 1432-1939
    Keywords: Drosophila ; Picornavirus ; Fertility ; Embryonic and larvo-pupal death rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drosophila C virus (DCV) has a considerable impact on ovarian morphogenesis inDrosophila melanogaster host populations. This virus also affects the developmental time and the fresh weight of infected females. In order to investigate the hypothesis that DCV may play a role in the dynamics ofDrosophila populations, the fertility and embryonic and larvo-pupal death rates of a host population and that of five DCV-free populations were determined. A comparison of two populations, one of them DCV-free, the other infected, suggested that the fertility of the DCV-infected flies was higher than that of uninfected flies, despite a greater larvo-pupal death rate. Fertility of the infected flies was greater among the infected population than for the DCV-free populations. The DCV-free populations originated from five different localities. The virus clearly does have an impact on the biotic potential of its host population. This paper reports for the first time a positive interaction between a viral population and a host population as it increases certain parameters of host population dynamics.
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  • 91
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    Biochemical genetics 26 (1988), S. 131-141 
    ISSN: 1573-4927
    Keywords: Drosophila ; arginine kinase ; mitochondria ; isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mitochondrial and cytoplasmic isozymes of arginine kinase have been identified inDrosophila melanogaster. On the basis of their immunological similarity, parallel dosage responses, and cosegregation of electrophoretic mobility differences, it is concluded that both isozymes are the product of a single gene. The consequences of this in relation to the regulation and evolution of this unusual gene-enzyme system are discussed. It is inferred that the origin of the phosphagen shuttle must predate the divergence of invertebrates and vertebrates.
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  • 92
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    Biochemical genetics 26 (1988), S. 783-803 
    ISSN: 1573-4927
    Keywords: Drosophila ; dipeptidase activities ; genetic variation ; activity modifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An examination ofDrosophila melanogaster from natural populations revealed genetic variation for dipeptidase-A (DIP-A) and dipeptidase-B (DIP-B) activities within sets of lines that differed from one another only in the second or the third chromosome. Analyses of diallel crosses indicate that both activities are inherited additively, and coordinate control of expression is suggested by the significant positive correlation between the two activities. Electrophoresis and thermal denaturation studies failed to detect structural differences among lines with different levels of DIP-A activity. No characteristic level of activity could be associated with any DIP-A allozyme. Mapping experiments revealed the presence of activity modifiers that are in tight linkage with the structural gene, as well as those that manifest their effects from a distance. The maximum genetic distance between a high-activity effect on DIP-A and the structural gene was determined to be 0.029 map unit. These results are in accordance with the prevalence of activity modifiers for various enzymes inDrosophila melanogaster.
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  • 93
    ISSN: 1573-4927
    Keywords: glutamine synthetase I ; genetic mapping ; allozymes ; null alleles ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recombinational and deletion mapping of electrophoretic variants of the glutamine synthetase I isozyme (GSI) inDrosophila melanogaster locates the gene in the 21B region on the second chromosome. We have conducted a genetic analysis of the region extending cytologically from 21A to 21B4-6. Recessive lethal mutations were generated by ethyl methanesulfonate (EMS) and ethyl nitrosourea (ENU) mutagenesis and by hybrid dysgenesis (HD). These lethals fall into seven functional groups, which were partially ordered by complementation with cytologically defined deficiencies of this region generated by hybrid dysgenesis. Two of the EMS- and two of the ENU-induced lethals fulfill biochemical criteria expected for null alleles of the GSI gene.
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  • 94
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    Biochemical genetics 26 (1988), S. 783-803 
    ISSN: 1573-4927
    Keywords: Drosophila ; dipeptidase activities ; genetic variation ; activity modifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An examination ofDrosophila melanogaster from natural populations revealed genetic variation for dipeptidase-A (DIP-A) and dipeptidase-B (DIP-B) activities within sets of lines that differed from one another only in the second or the third chromosome. Analyses of diallel crosses indicate that both activities are inherited additively, and coordinate control of expression is suggested by the significant positive correlation between the two activities. Electrophoresis and thermal denaturation studies failed to detect structural differences among lines with different levels of DIP-A activity. No characteristic level of activity could be associated with any DIP-A allozyme. Mapping experiments revealed the presence of activity modifiers that are in tight linkage with the structural gene, as well as those that manifest their effects from a distance. The maximum genetic distance between a high-activity effect on DIP-A and the structural gene was determined to be 0.029 map unit. These results are in accordance with the prevalence of activity modifiers for various enzymes inDrosophila melanogaster.
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  • 95
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    Biochemical genetics 26 (1988), S. 527-541 
    ISSN: 1573-4927
    Keywords: Drosophila ; glue proteins ; glycosylation ; Chromosomal linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larval glue protein fractions ofDrosophila nasuta nasuta were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Seven major and at least four minor glue protein fractions were recognized. Six of the major fractions are glycosylated. They migrate as three prominent doublets (〉100, 43, and 30/28 kd). The synthesis of traceable amounts of these major fractions begins already during the second as well as during the early stages of the third larval instar. The 43-kd and the 30/28-kd fractions are coded by X-chromosomal genes. They are probably clustered within the huge puff of division 10, which is the most prominent X-chromosomal puff in the polytene chromosomes of the third larval instar. Complex posttranslational modification of all but one major glue protein fraction (14 kd) leads to the formation of about 15 different protein fractions in the final glue product. The amount of glue protein produced byD. n. nasuta larvae (in relation to the total saliva proteins) is nearly twice the amount produced byD. melanogaster larvae (ca. 55 and 32%, respectively).
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  • 96
    ISSN: 1573-4927
    Keywords: glutamine synthetase I ; genetic mapping ; allozymes ; null alleles ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recombinational and deletion mapping of electrophoretic variants of the glutamine synthetase I isozyme (GSI) inDrosophila melanogaster locates the gene in the 21B region on the second chromosome. We have conducted a genetic analysis of the region extending cytologically from 21A to 21B4-6. Recessive lethal mutations were generated by ethyl methanesulfonate (EMS) and ethyl nitrosourea (ENU) mutagenesis and by hybrid dysgenesis (HD). These lethals fall into seven functional groups, which were partially ordered by complementation with cytologically defined deficiencies of this region generated by hybrid dysgenesis. Two of the EMS- and two of the ENU-induced lethals fulfill biochemical criteria expected for null alleles of the GSI gene.
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  • 97
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    Molecular and cellular biochemistry 79 (1988), S. 181-189 
    ISSN: 1573-4919
    Keywords: zerknullt gene ; homeobox protein ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The zen protein is encoded by the zerknullt gene required for normal early development inDrosophila. Like many regulatory proteins of this type, zen contains a 60 amino acid homeobox sequence. We have purified the zen protein and studied its solution behavior and its interaction with DNA. The zen protein exists as a monomer in solution with a molecular weight of about 40000. It binds specifically to a site about 900 bases upstream from thezen gene. Within this binding site DNase protection experiments indicate that binding is confined to two regions approximately 11 and 14 bases in length that are separated by about 30 base pairs. The protein concentration dependence of the binding curve suggests that protein binding is non cooperative.
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  • 98
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    Biochemical genetics 26 (1988), S. 527-541 
    ISSN: 1573-4927
    Keywords: Drosophila ; glue proteins ; glycosylation ; Chromosomal linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larval glue protein fractions ofDrosophila nasuta nasuta were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Seven major and at least four minor glue protein fractions were recognized. Six of the major fractions are glycosylated. They migrate as three prominent doublets (〉100, 43, and 30/28 kd). The synthesis of traceable amounts of these major fractions begins already during the second as well as during the early stages of the third larval instar. The 43-kd and the 30/28-kd fractions are coded by X-chromosomal genes. They are probably clustered within the huge puff of division 10, which is the most prominent X-chromosomal puff in the polytene chromosomes of the third larval instar. Complex posttranslational modification of all but one major glue protein fraction (14 kd) leads to the formation of about 15 different protein fractions in the final glue product. The amount of glue protein produced byD. n. nasuta larvae (in relation to the total saliva proteins) is nearly twice the amount produced byD. melanogaster larvae (ca. 55 and 32%, respectively).
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  • 99
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    Behavior genetics 18 (1988), S. 293-308 
    ISSN: 1573-3297
    Keywords: stress ; domestication ; extreme environments ; human evolution ; mice ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Genetic variability of behavioral traits under optimal and stressful environments is considered with examples fromDrosophila, rodents, and our own species. In agreement with direct fitness and life history traits, behavioral traits show a maximization of preexisting andde novo variation under stress. In order to understand evolutionary change,it appears necessary to emphasize those traits showing interactions with habitats under conditions of environmental stress; this can be shown at the behavioral level especially for domestication and adaptation to novel habitats.
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  • 100
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    Behavior genetics 18 (1988), S. 389-403 
    ISSN: 1573-3297
    Keywords: sexual selection ; sexual behavior ; assortative mating ; polymorphism ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Although many experiments on laboratory stocks ofDrosophila have suggested that mate choice is a major feature of sexual selection in this organism, few attempts have been made to measure its extent in wild populations. In this study, a crossing design was used to obtain a set of 13 genetically identical independent lines representative of genotypes from an African population ofDrosophila melanogaster. They were tested for variation in sexual behavior using dyadic tests. Significant variation in orientation and vibration latencies was found for males, and in mating speed and copulation duration for both sexes. No evidence of assortative mating, either positive or negative, was found. The absence of a correlation in mating speed between males and females sharing the same genotype leads us to doubt the applicability of the notion of “male eagerness” and “female reluctancy” inDrosophila and the importance of “vigor” as a factor in mating speed. The absence of mate choice in natural populations ofDrosophila seems to us the most likely hypothesis on the basis of both theory and empirical evidence.
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