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  • Articles  (32)
  • 42.55
  • Chemical Engineering
  • Drosophila
  • Electronic structure and strongly correlated systems
  • Saccharomyces cerevisiae
  • Springer  (32)
  • 1980-1984  (32)
  • Chemistry and Pharmacology  (32)
  • 1
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    Biochemical genetics 22 (1984), S. 153-168 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; activity ratio ; specific activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thirteen Drosophila Adh variants have been characterized with respect to gene expression, substrate preference, thermostability, and specific activity. The results suggest that the variants may be grouped into two biochemical classes, typified by the properties of the two most common enzyme forms, ADH-F and ADH-S. Membership of these classes cannot be predicted from electrophoretic mobility, nor is any simple classification possible with regard to the characteristics of level of gene expression (in terms of ADH activity or ADH protein) or thermostability of the gene product.
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  • 2
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    Biochemical genetics 22 (1984), S. 1015-1029 
    ISSN: 1573-4927
    Keywords: acetaldehyde ; alcohol dehydrogenase ; aldehyde oxidase ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Metabolic utilization and toxicity of acetaldehyde were studied in flies lacking alcohol dehydrogenase (ADH), aldehyde oxidase (AO), or both functions. Prior to the experiments, mutant alleles Adh n4 and mal were transferred to the same genetic background by 10 successive backcrosses. By comparison with wild-type flies, various deleterious, pleiotropic effects could be attributed to the mal allele but not to Adh n4 . Of the four genotypes studied (mal, Adh n4 , mal Adh n4 , and wild), all were able to use acetaldehyde as a resource in a similar way. In spite of its high toxicity, acetaldehyde appeared a better resource than ethanol. Flies treated with intermediate acetaldehyde concentrations (around 0.5%) exhibited a very high interindividual heterogeneity which could reflect a physiological adaptation occurring as a consequence of the aldehyde treatment. Toxicity tests showed that ADH-negative flies were more sensitive to acetaldehyde than wild type, but this is most likely explained by the transformation of the aldehyde into alcohol. Our results show that the aldehyde metabolizing enzyme (AME) system in Drosophila is neither ADH nor AO. The existence of an aldehyde dehydrogenase is plausible.
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  • 3
    ISSN: 1573-1561
    Keywords: Leptopilinaheterotoma ; Hymenoptera ; Eucoilidae ; Saccharomyces cerevisiae ; host-habitat searching ; chemoreception ; fermentation products ; ethanol ; ethyl acetate ; acetaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemical stimuli play an important role in the process of searching for a host habitat by parasitic wasps. Volatile compounds originating from host habitats and/or hosts are the cues that enable such a location.Leptopilina heterotoma, a larval parasite ofDrosophila, is attracted to the food of its host, baker's yeast. Analysis of the fermentation products of baker's yeast, using a mass spectrometer, and olfactometer studies indicate that three fermentation products of this yeast, the main component of the host habitat in our laboratory, attractL. heterotoma: ethanol (5%), ethyl acetate (10−2, 10−3%), and acetaldehyde (1%). A combination of these three compounds, however, cannot compete with baker's yeast in attracting the parasites. Thus other factors, such as different compounds, concentrations, and/or combinations, also, play a role and remain to be tested.Leptopilina heterotoma does not use host-related olfactory cues in long-distance habitat location as it cannot distinguish between host habitat and host habitat with hosts.
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  • 4
    ISSN: 1573-6881
    Keywords: H+-ATPase complex ; assembly defect ; Saccharomyces cerevisiae ; mitochondrial biogenesis ; membrane association
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract We have investigated the extent to which the assembly of the cytoplasmically synthesized subunits of the H+-ATPase can proceed in a mtDNA-less (rho°) strain of yeast, which is not capable of mitochondrial protein synthesis. Three of the membrane sector proteins of the yeast H+-ATPase are synthesized in the mitochondria, and it is important to determine whether the presence of these subunits is essential for the assembly of the imported subunits to the inner mitochondrial membrane. A monoclonal antibody against the cytoplasmically synthesized β-subunit of the H+-ATPase was used to immunoprecipitate the assembled subunits of the enzyme complex. Our results indicate that the imported subunits of the H+-ATPase can be assembled in this mutant, into a defective complex which could be shown to be associated with the mitochondrial membrane by the analysis of the Arrhenius kinetics of the mutant mitochondrial ATPase activity.
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  • 5
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    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Keywords: Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
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  • 6
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    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Keywords: Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
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  • 7
    ISSN: 1573-4927
    Keywords: Drosophila ; alcohol dehydrogenase ; enzyme polymorphisms, activity ratios
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Representatives of five allozymic classes of Drosophila alcohol dehydrogenase have been compared with respect to their activity levels on two alcohol substrates, quantities of ADH protein, and stability in crude extracts. Within each allozymic class, strains from widely diverse geographic locations differ in their enzyme activity levels but are identical for a measure known as “activity ratio,” which is obtained by dividing the average activity reading on isopropanol by that obtained with ethanol. They are also similar in the rate at which ADH activity declines in crude extracts held at 25°C. For several of the fast-resistant and fast-moderate strains, differences in ADH activity are associated with differences in the amount of enzyme present. The catalytic efficiencies of the fast-resistant forms are considerably lower than those of the fast-moderate allozymes. The origin and persistence of the rare but ubiquitous fast-resistant allozyme is discussed.
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  • 8
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    Biochemical genetics 21 (1983), S. 703-711 
    ISSN: 1573-4927
    Keywords: Drosophila ; glucose-6-phosphate dehydrogenase ; polymorphism ; sequential electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Studies were undertaken to investigate two critical aspects of the glucose-6-phosphate dehydrogenase polymorphism in Drosophila melanogaster. The first investigation unequivocally maps the genetic site of the G6PD locus to the X chromosome. The second study subjects a set of isochromosomal lines to sequential electrophoresis in an attempt to uncover common molecular heterogeneity within the global polymorphism, assuming that this variation may have gone undetected under conventional electrophoretic conditions. The genetic site was mapped following the segregation of the two common electrophoretic alleles, a so-called null allele, and two rare electrophoretic variants. From the pooled results, the Zw locus mapped to 62.9 on the X chromosome relative to the flanking markers car (at 62.5) and sw (at 64.7). A set of 126 iso-X chromosomal lines of diverse geographic origin was subjected to sequential electrophoresis under three different acrylamide conditions in addition to the conventional starch electrophoretic system. No additional variation beyond the common diallele polymorphism was seen.
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  • 9
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    Biochemical genetics 21 (1983), S. 365-374 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; NAD+ levels ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Previous studies carried out in mammalian systems indicated that an organism's NAD+/NADH balance is carefully regulated but can be destabilized by dietary stresses. Since Drosophila alcohol dehydrogenase (ADH) uses NAD+ to remove a hydrogen from ethanol in the first step of alcohol catabolism, it is possible that under alcohol stress conditions the in vivo NAD+ levels in Drosophila may decrease. In this study genetically homozygous flies were stressed with maximally sublethal concentrations of ethanol (10%) for periods of up to 24 hr. The results indicate that NAD+ levels do in fact drop by at least 20% in response to ethanol stress. Evidence is presented that suggests that this decrease is the direct result of ADH-mediated catabolism.
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  • 10
    ISSN: 1432-1424
    Keywords: electron probe X-ray microanalysis ; Saccharomyces cerevisiae ; ethidium ; brontophenol blue ; cationic dye ; cytolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary K+ efflux provoked by ethidium proceeds partially as an all-or-none effect by which the diffusion barrier for K+ is disrupted and partially from still intact cells, presumably by exchange against ethidium. This is shown by the application of an electron probe microanalysis X-ray technique by which the K+ content of a number of individual cells is analyzed.
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  • 11
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; pyridoxal oxidase ; tissue specificity ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The substrate specificities of aldehyde and pyridoxal oxidases in Drosophila melanogaster have been determined with a variety of aliphatic and aromatic aldehydes. This analysis has led to the discovery that 2,4,5-trimethoxy-benzaldehyde is a specific substrate for pyridoxal oxidase, as based on the histochemical distribution of oxidase activity, the absence of enzymatic activity in the lpo 1strains, and the dosage dependence on the number of lpo +genes present. The tissue-specific localization of aldehyde oxidase (AO) and pyridoxal oxidase (PO) in the larval and adult structures showed that AO was present in all the major internal organs of the larvae and adults, including brain, imaginal discs, Malpighian tubules, digestive system, and reproductive structures. Pyridoxal oxidase is present in many of the same structures which possess AO, but is missing from the cardia, crop, imaginal discs, ovarian follicle cells, paragonia, pericardial cells, and wreath cells. The only structure which possesses PO but lacks AO is the larval salivary gland. These histochemical differences in AO and PO distribution were also confirmed by enzymatic analysis of the activities present in homogenates of ovaries, paragonia, and salivary glands. The general pattern of enzyme expression appears to be established during embryogenesis and maintained throughout the life of the individual.
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  • 12
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    Biochemical genetics 20 (1982), S. 461-474 
    ISSN: 1573-4927
    Keywords: Drosophila ; allozymes ; α-Gpdh ; selection ; genetic background
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three sets of experiments have been conducted in order to evaluate the role of natural selection at the α-Gpdh locus in Drosophila melanogaster. (1) The evolution of the F-allele frequency has been followed for many generations in 13 experimental populations having different genetic backgrounds. (2) Egg-to-adult viability has been measured in synthetic populations derived from one locality (Brouilly) and the results have been compared with those of a previous experiment involving a different local population (Tostes). (3) The effects of sodium octanoate on egg-to-adult viability have been measured on the genotypes FF, FS, SF, and SS. The results demonstrate that selection operates on a small block of genes which includes the α-Gpdh locus.
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  • 13
    ISSN: 1573-4927
    Keywords: esterase ; duplication ; gene expression ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An esterase duplication is described in the sibling species pair Drosophila mojavensis and Drosophila arizonensis. We present evidence for two separate structural loci mapping at a distance of less than 0.16 recombination units from each other. Alleles at the two loci have the same substrate specificities and form small amounts of interlocus heterodimers. One locus (Est-5) is functioning throughout the insect's life cycle and appears at high concentrations in the hemolymph and the fat body. Its duplicate (Est-4) functions only during the late larval stage and is concentrated mainly in the carcass. No null alleles at either locus were observed in population surveys. An examination of 12 other species from the repleta group, to which D. mojavensis and D. arizonesis belong, suggests that Est-5 is universally present, but the activity levels of Est-4 vary among species and may be totally absent in some species. Variation in the level of Est-4 activity does not closely follow the phylogenetic relationship.
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  • 14
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    Biochemical genetics 20 (1982), S. 179-198 
    ISSN: 1573-4927
    Keywords: acetylcholinesterase ; Drosophila ; malathion ; insecticide resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationship between the 50% survival time for flies feeding on a malathion-containing medium and the activity of acetylcholinesterase (AChE) was determined for 15 isofemale lines of Drosophila melanogaster. A significant correlation was found (r=0.28, P〈0.05), with more resistant lines tending to have a lower level of AChE activity. An association between AChE and malathion resistance was also observed in a selection experiment. The AChE activity decreased in two of two populations selected for malathion resistance. AChE from these populations was altered in kinetic parameters (measured in crude head extracts) and electrophoretic mobility. Although the “resistant” AChE had a lower activity (V m) on either a per milligram protein or a per individual basis, its apparent K m for acetylthiocholine was lower than that of “susceptible” AChE. Recombination mapping of both low activity and fast electrophoretic mobility localized these traits to the region of the structural locus (Ace) on the third chromosome. The AChE activity of flies heterozygous for a variety of Ace lesions (kindly provided by Dr. W. M. Gelbart) was consistent with this location. The changes in AChE were suggested to have been caused by selection of alleles at the Ace locus.
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  • 15
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    Biochemical genetics 20 (1982), S. 407-424 
    ISSN: 1573-4927
    Keywords: dipeptidases ; Drosophila ; variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three dipeptidases in Drosophila melanogaster are under independent genetic control and their structural genes have been localized, Dip-A to 2R and Dip-B and Dip-C to 3R (Voelker and Langley, 1978; Ohnishi and Voelker, 1981). These enzymes were characterized with respect to their substrate specificities, genetic variability (electrophoretic mobility and quantitative activity level), ontogeny (activity and isozyme pattern), and tissue localization. The dipeptide substrate specificities of DIP-A and DIP-B overlap each other considerably, but do not overlap with DIP-C. In natural populations, DIP-B and DIP-C are essentially monomorphic electrophoretically whereas DIP-A is polymorphic for three allozymes. Both DIP-A and DIP-B show quantitative genetic variation of activity level within an allozyme class. All three enzymes are expressed at all stages in the life cycle, but DIP-A and DIP-B activities vary considerably according to developmental stage and sex of adult. The tissue localizations of DIP-A and DIP-B activities show similar patterns and a nearly ubiquitous occurrence of both enzymes, but with particularly high values in larval and adult midguts and in the adult female reproductive system. These results suggest a general metabolic role for the enzymes, such as regulation of the concentrated pools of amino acids and oligopeptides found in Drosophila tissues.
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  • 16
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; selection ; ethanol ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Drosophila melanogaster larvae were subjected to 10 generations of selection on 6% ethanol at 17, 25, and 30°C. For each temperature there was a significant (P〈0.01) increase in the frequency of the Adh isoallele. Controls with no ethanol showed no change in the frequency of the Adh F isoallele. Larvae subjected to stronger selection on 8% ethanol confirmed the results. When adults of various ages were subjected to 16 and 32°C, the ADHF isoenzyme retained its twofold advantage in activity over ADHS regardless of the temperature. The same result was obtained with larvae at 16 and 35°C. Although some effect of temperature was demonstrated, it was concluded that the effect was not strong enough for temperature to be a selective factor under the conditions studied. However, ethanol is a strong selective factor for laboratory populations.
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  • 17
    ISSN: 1573-6881
    Keywords: Respiratory chain ; ATP synthesis ; mitochondria ; ubiquinone ; Saccharomyces cerevisiae ; cytochrome oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Mitochondria, isolated from the ubiquinone-deficient nuclear mutant ofSaccharomyces cerevisiae E3-24, are practically unable to oxidize exogenous substrates. Respiratory activity, coupled to ATP synthesis, can, however, be reconstituted by the simple addition of ethanolic solutions of ubiquinones. A minimal length of the isoprenoid side chain (≥3) was required for the restoration. Saturation of the reconstitution required a large amount of exogeneous ubiquinone, in excess over the normal content present in the mitochondria of the wild type strain. A similar pattern of reconstituted activities could be also obtained using sonicated inverted particles. Mitochondria and sonicated particles are also able to carry out a dye-mediated electron flow coupled to ATP synthesis in the absence of added ubiquinone, using ascorbate or succinate as electron donor. This demonstrates that the energy conserving mechanism at the third coupling site of the respiratory chain is fully independent of the presence of the large mobile pool of ubiquinone in the membrane.
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  • 18
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    Biochemical genetics 19 (1981), S. 567-583 
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; Drosophila ; evolution ; gene regulation ; isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract At least four enzymes contribute to histochemically, electrophoretically, or spectrophotometrically detectable aldehyde oxidase (AO) activity in Drosophila melanogaster. The one we designate AO-1 contributes the majority of activity measured in extracts of whole flies. Pyridoxal oxidase (PO) is also a broad range AO. It is prominent only in midgut and Malpighian tubules, where it apparently accounts for a substantial fraction of total AO activity. The tissue distributions of these enzymes are clearly disparate despite close linkage of their structural loci and parallel dependence on the mal, lxd, and cin loci. A similarly related enzyme, xanthine dehydrogenase (XDH), is detected as an AO only in electrophoretic gels. A fourth broad range AO, not dependent on mal, lxd, and cin, is confined to the ejaculatory bulb. A similar array of AO isozymes is present in phylogenetically distant Drosophila species.
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  • 19
    ISSN: 1573-4927
    Keywords: dipeptidases ; variation ; allozymes ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Genetic variation at three dipeptidase loci (Dip-A, Dip-B, and Dip-C) in Drosophila simulans was analyzed by starch gel electrophoresis. Dip-A was found to be polymorphic in four populations, while Dip-B and Dip-C were found to be polymorphic in one. The numbers of different alleles found at each respective locus were: Dip-A, two; Dip-B, two; and Dip-C, three. Dip-A was genetically mapped at 57.9 on the second chromosome, and Dip-B and Dip-C at 80.9 and 87.9 on the third chromosome, respectively. Neither Dip-B nor Dip-C has been mapped in D. melanogaster because both loci are apparently monomorphic. Their map positions in D. simulans with respect to flanking markers whose homologous genes have been cytogenetically localized in D. melanogaster suggested that they might be mapped cytogenetically by using available deficiencies in D. melanogaster. Accordingly, by the construction of interspecific hybrids which carried deficiencies of melanogaster and an allele of simulans with a mobility different from that of the fixed melanogaster allele, Dip-B and Dip-C were localized between 87F12-14 and 88C1-3 and between 87B5-6 and 87B8-10, respectively, in the salivary gland chromosomes of D. melanogaster. The similarity between these two species is discussed on the basis of these findings.
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  • 20
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    Biochemical genetics 19 (1981), S. 115-127 
    ISSN: 1573-4927
    Keywords: Drosophila ; dihydroorotate dehydrogenase ; pyrimidine biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A locus is described that controls levels of mitochondrial dihydroorotate dehydrogenase (EC 1.3.3.1) in Drosophila melanogaster. The effects of alleles of the locus, Dhod, are manifest in preparations from whole organisms as well as in partially purified mitochondrial preparations; however, other mitochondrial functions do not appear to be appreciably affected by Dhod genotypes. The locus maps near p in the proximal portion of the right arm of chromosome 3. Flies trisomic for a chromosome segment including that region display elevated enzyme levels, implying that an enzyme structural gene is in that vicinity. Furthermore, Dhod alleles are semidominant in heterozygotes, suggesting that the dosage-sensitive element detected in the trisomics is actually the Dhod locus. These findings are discussed relative to the role of dihydroorotate dehydrogenase in the de novo pyrimidine biosynthetic pathway and relative to other pathway mutants that have been described in Drosophila.
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  • 21
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    Biochemical genetics 19 (1981), S. 311-320 
    ISSN: 1573-4927
    Keywords: Drosophila ; thermal stability of enzyme ; α-glycerophosphate dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thermal stability of α-glycerophosphate dehydrogenase-1 (α-Gpdh-1) in nine Drosophila species was studied at pH's ranging from 6.4 to 8.5. This was done by measuring the changes in the activity of enzymes during the heat denaturation process. In addition to temperature, the rate of denaturation is highly dependent on the pH of the incubation buffer. The results of this study show that the thermal stability of enzyme molecules is different in different species. This holds true also in the species in which the enzymes have been found to be identical by other means. The differences between species of the Drosophila virilis group are discussed.
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  • 22
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    Biochemical genetics 19 (1981), S. 321-331 
    ISSN: 1573-4927
    Keywords: Drosophila ; embryonic cells ; actin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In a permanent cell line derived from Drosophila embryos, cytoplasmic actin is produced as an unstable precursor, which is subsequently converted to a stable form. This conversion results in a reduction in isoelectric point, with no apparent change in molecular weight. The conversion involves an enzymatic acetylation, and results in an insensitivity to aminopeptidase digestion, suggesting N-terminal blockage. Both the acetylated and unacetylated actins can participate in the assembly of F-actin, but with different efficiencies.
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  • 23
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    Biochemical genetics 19 (1981), S. 411-419 
    ISSN: 1573-4927
    Keywords: half life ; Drosophila ; alcohol dehydrogenase ; enzyme stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A rapid and accurate method of measuring the relative in vivo stability of Drosophila alcohol dehydrogenase is presented. The potential of this technique for examining posttranslational control of in vivo enzyme concentrations is discussed.
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  • 24
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    Biochemical genetics 19 (1981), S. 421-430 
    ISSN: 1573-4927
    Keywords: Drosophila ; alcohol dehydrogenase ; adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effects of environmental 2-propanol on the in vivo properties of Drosophila alcohol dehydrogenase (E.C. 1.1.1.1.) are presented. Exposed flies were found to exhibit a significant decrease in ADH specific activity with a concomitant increase in the enzyme's relative in vivo stability and concentration. The possible adaptive significance of the observed responses is discussed.
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  • 25
    ISSN: 1573-4927
    Keywords: Drosophila ; amylase ; gene regulation ; trans effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Purified amylases from high- and low-activity variants of Drosophila melanogaster showed identical specific activities. Immunoelectrophoresis of crude larval homogenates showed severalfold differences between strains in the amounts of cross-reacting material. Control of amylase activity is “trans”-acting in heterozygotes between high- and low-activity variants. These results suggest the existence of polymorphic regulatory genes affecting the production levels of amylase protein in D. melanogaster.
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  • 26
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    Biochemical genetics 19 (1981), S. 947-954 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; cryptic variants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thirty-five cryptic variant lines were used to examine the mechanisms involved in genetic modulation of alcohol metabolism in Drosophila. Late third-instar larval, preemergence pupal, and adult stages cultured at 18 and 28 C were examined. Spectrophotometric analyses for native alcohol dehydrogenase (ADH) activity and residual ADH activity after treatment with guanidine hydrochloride and heat were performed. Differential response of cryptic variants to treatment with the denaturants during development suggested that this variation may have an adaptive significance.
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  • 27
    ISSN: 1573-4927
    Keywords: Drosophila ; molybdoenzymes ; sulfite oxidase ; tungstate feeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Sulfite oxidase (sulfite: ferricytochrome c oxidoreductase; EC 1.8.2.1) has been detected in Drosophila melanogaster and some of its properties have been studied. In most respects this enzyme resembles the mammalian sulfite oxidases except for its molecular weight (148,000), which is somewhat higher than that of rat sulfite oxidase (116,000). Cytochrome c, potassium-ferricyanide, and oxygen can serve as electron acceptors in the oxidation of sulfite by the enzyme. Although definite evidence can be obtained only through the analysis of the pure enzyme, experiments involving tungstate feeding suggest that Drosophila sulfite oxidase is most probably a molybdoenzyme. Extracts of mal flies show normal levels of sulfite oxidase, whereas lxd flies have only 5–10% of the activity of wild type, and in cin flies the enzyme is apparently absent. While it is possible that the lxd and cin mutations are at some level responsible for the defective synthesis of a molybdenum-containing cofactor (supposed to be present in most molybdoenzymes), the evidence accumulated so far by several authors and the results of the present investigation argue against the involvement of a Mo cofactor in the multiple enzyme deficiencies observed in mal flies.
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  • 28
    ISSN: 1573-4927
    Keywords: Drosophila ; ontogeny ; amylase ; α-glucosidases ; functional significance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Changes in amylase (E.C. 3.2.1.1), maltase (E.C. 3.2.1.20), sucrase, and PNPGase activities in relation to changes in wet weight and protein content were studied during the development of larvae and adult flies from two strains of Drosophila melanogaster, homozygous for different amylase alleles. All α-glucosidase activities increase exponentially during a large part of larval development, parallel to the increase in weight, and drop at the end of the third instar. Amylase activity of the Amy 1 strain follows the same pattern. In contrast, amylase activity of the Amy 4,6 strain continues its exponential increase longer. In the third larval instar amylase activity in the Amy 4,6 strain becomes much higher than in the Amy 1 strain. During the first hours of adult life amylase activity of the two strains does not differ. Then Amy 4,6 activity starts to rise and becomes much higher (4–5 times) than Amy 1 amylase activity, which remains approximately constant. All adult enzyme activities are much higher than in larvae. Comparison of enzyme activity of amylase and α-glucosidases in larvae and adults confirms that differences in amylase activities can become important only when starch is a limiting factor in the food.
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  • 29
    Electronic Resource
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    Biochemical genetics 18 (1980), S. 439-454 
    ISSN: 1573-4927
    Keywords: Drosophila ; acetylcholinesterase ; insecticide resistance ; electrophoretic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We examined the Canton-S strain of Drosophila melanogaster for electrophoretic variation of the enzyme acetylcholinesterase. The pattern of bands obtained (stained with acetylthiocholine) depended on age, sex, and tissue (i.e., head vs. body part and hemolymph). However, through mixing experiments, it was concluded that most of these apparent differences were due to modification of the enzyme by unknown substances located in the fly's body. The electrophoretic pattern of head acetylcholinesterase was altered so that it became characteristic of the body which was present during extraction. For example, when heads of D. melanogaster were homogenized in an extract from D. lebanonensis bodies, the characteristic AChse bands of melanogaster were absent and instead the bands of lebanonensis were found. it was found that extraction of adult heads in 0.1 M potassium phosphate buffer alone or with a 2-min exposure to 1 mg/ml trypsin at 20 C gave the most reproducible results, independent of age and sex. Using these conditions, 25 strains of D. melanogaster and 30 strains of D. pseudoobscura were examined without finding any reproducible electrophoretic variant of acetylcholinesterase. In addition, 53 strains from 39 other Drosophila species produced a total of only six electrophoretic forms of the head enzyme. Additional electromorphs were found when whole flies were used, but these were not studied in detail because of the possibility that they could be due to postextraction modification.
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  • 30
    Electronic Resource
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    Springer
    Biochemical genetics 18 (1980), S. 717-726 
    ISSN: 1573-4927
    Keywords: Drosophila ; 5-fluorouracil ; drug response ; thymidylate synthetase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mutant strains sensitive and resistant to the drug 5-fluorouracil (FU) have been isolated from the wild-type Pac strain of Drosophila melanogaster. The resistant strain, termed flur, is resistant to at least 0.0035%FU (2.7 × 10−4 m) in the food media and exhibits cross-resistance to 5-fluorodeoxyuridine (FUdR) but not to 5-fluorouridine (FUR). The sensitive strain termed flu S , exhibits over 90% mortality on 0.0008% FU (6 × 10−5 m). Genetic analysis indicates that the flu gene is located on the third chromosome, which agrees with results of previous workers. An analysis of the enzyme thymidylate synthetase from the selected sensitive and resistant strains indicates that the resistant strain enzyme possesses an elevated specific activity. Levels 4 times that of the sensitive strain were observed when the enzymes were assayed at 20 C. This increase is apparently not due to induction by FU in the food media. It is suggested that the enzyme thymidylate synthetase may be involved in the resistance process.
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  • 31
    Electronic Resource
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    Springer
    Biochemical genetics 18 (1980), S. 781-791 
    ISSN: 1573-4927
    Keywords: Drosophila ; phenylalanine hydroxylase ; developmental regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Herein we demonstrate that Drosophila larvae possess a synthetic activity capable of converting phenylalanine to tyrosine. This system is readily extractable and displays many characteristics of phenylalanine hydroxylase systems described in other organisms, the most notable being that a tetrahydropteridine is required for full expression of activity. The level of phenylalanine hydroxylase activity present in the organism varies with the stage of development: from an undetected level of activity at the first larval instar, there is a rapid increase in phenylalanine hydroxylase activity which reaches a peak at the time of puparium formation, after which there is a rapid decrease again to an undetected level.
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  • 32
    Electronic Resource
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    Springer
    Biochemical genetics 18 (1980), S. 929-937 
    ISSN: 1573-4927
    Keywords: glucose oxidase ; glucose metabolism ; Drosophila ; sex specific
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A glucose oxidase (GO) has been identified in the ejaculatory duct of male Drosophila melanogaster. Evidence is given that this enzyme was previously misidentified as HEX-1. Genetic analysis indicates that the Go structural gene is located on the third chromosome at 48 ± 0.5 cm. Go is polymorphic in males in populations of D. melanogaster and D. simulans located in Athens, Georgia. Two other hexose enzymes have also been tentatively identified for the first time in Drosophila. These are NAD(P)-glucose dehydrogenase (GODH) and NAD-gluconate dehydrogenase (GNDH). GODH and GNDH are found in both males and females and may circumvent the initial steps in the pentose shunt.
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