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  • Drosophila
  • Springer  (28)
  • American Chemical Society
  • 1985-1989  (28)
  • 1980-1984
  • 1950-1954
  • 1945-1949
  • 1925-1929
  • 1989  (28)
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  • 1985-1989  (28)
  • 1980-1984
  • 1950-1954
  • 1945-1949
  • 1925-1929
Year
  • 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
    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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  • 21
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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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  • 22
    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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  • 23
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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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  • 24
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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
    Source: Springer Online Journal Archives 1860-2000
    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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  • 25
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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
    Source: Springer Online Journal Archives 1860-2000
    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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  • 26
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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
    Source: Springer Online Journal Archives 1860-2000
    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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  • 27
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    Journal of comparative physiology 159 (1989), S. 237-242 
    ISSN: 1432-136X
    Keywords: Amylase ; Mosquitofish ; Rat ; Drosophila ; Structure ; Function
    Source: Springer Online Journal Archives 1860-2000
    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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  • 28
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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
    Source: Springer Online Journal Archives 1860-2000
    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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