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  • Artikel  (132)
  • Drosophila melanogaster
  • Mitochondria
  • Springer  (126)
  • Wiley-Blackwell  (6)
  • Periodicals Archive Online (PAO)
  • 1975-1979  (127)
  • 1965-1969  (5)
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  • Artikel  (132)
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  • Springer  (126)
  • Wiley-Blackwell  (6)
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  • 1
    Digitale Medien
    Digitale Medien
    Stabilization of amorphous calcium phosphate by Mg and ATP (1977)
    Springer
    Calcified tissue international 23 (1977), S. 245-250 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Stabilization ; Amorphous calcium phosphate ; Mitochondria ; Mg and ATP ; Nucleation poisoning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary A synergistic effect has been demonstrated when magnesium and adenosine triphosphate (ATP) are used together in solution to delay the conversion of a slurry of amorphous calcium phosphate (ACP) to crystalline hydroxyapatite (HA). Conversion is delayed in some instances more than 10 times as long as with either ATP or Mg alone. In all experiments conversion did not begin until ATP in solution had decreased through hydrolysis to an undetectable level. The effect of Mg is to decrease substantially the rate at which ATP hydrolysis occurs. Once conversion began it proceeded more slowly in the presence of both Mg and ATP than with Mg or ATP alone. ATP was also found to prevent the formation of HA from metastable solutions of calcium and phosphate which did not contain any solid phase. Over the time period of these experiments, ATP hydrolyzed to a negligible extent in Tris-HCl buffer and in solutions containing Ca, PO4, and Ca plus PO4 ions. Hydrolysis of ATP does occur in the presence of ACP or HA, presumably by transphosphorylation on the surface of the solid calcium phosphate phase. It was concluded that ATP stabilized ACP, not by affecting its dissolution, but either by poisoning heteronuclear growth sites, or by poisoning the growth of embryonic HA nuclei (formed heterogeneously or homogeneously) before their critical size is reached, or by poisoning both. In the case of embryonic HA nuclei, the poisoned nuclei would go back into solution preventing HA crystal formation. In addition, it was found that the neutral Ca9(PO4)6 clusters, which are believed to be the basic structural unit of ACP, break down into individual Ca and PO4 ions when ACP dissolves in aqueous medium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012793
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  • 2
    Digitale Medien
    Digitale Medien
    The origin of mitochondria (1975)
    Springer
    Journal of molecular evolution 5 (1975), S. 167-176 
    Details
    ISSN: 1432-1432
    Schlagwort(e): Mitochondria ; Endosymbiont Hypothesis ; Episome Hypothesis ; Duplication ; Compartimentalisation ; Enslavement Hypothesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The endosymbiont and episome theories about the origin of mitochondria are reviewed. Biochemical and genetic data, relevant to these theories are discussed. An alternative theory is also proposed; this theory is that nuclear and mitochondrial DNAs developed from compartmentalized duplicate prokaryote DNAs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01741239
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  • 3
    Digitale Medien
    Digitale Medien
    Organization and evolution of the mitochondrial genome of yeast (1976)
    Springer
    Journal of molecular evolution 9 (1976), S. 25-35 
    Details
    ISSN: 1432-1432
    Schlagwort(e): Genome organization ; Evolution ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The mitochondrial genome of yeast (S. cerevisiae orS. carlsbergensis) appears to be formed by 60–70 genetic units, each one of which is formed by (1) a GC-rich sequence, possibly having a regulatory role; (2) a gene, and (3) an AT-rich spacer, which probably is not transcribed. Recombination in this genome appears to underlie a number of important phenomena. The organization of the mitochondrial genome of yeast and these recombinational events are discussed in relationship with the organization and evolution of the nuclear genome of eukaryotes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01796120
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  • 4
    Digitale Medien
    Digitale Medien
    Action de la rubratoxine B sur la respiration des mitochondries hépatiques de rat (1975)
    Springer
    Mycopathologia 55 (1975), S. 53-55 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Rubratoxine B ; Mitochondria ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The in vitro effect of rubratoxin B on the electron transport system of rat liver mitochondria was investigated. This mycotoxin depressed oxygen consumption in ADP-lacking mitochondria and in ADP-coupled mitochondria, using succinate or β-hydroxybutyrate as substrats. Rubratoxin B is neither an oxidative-phosphorylation inhibitor nor uncoupling agent. Its effect is compared with aflatoxin B1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00467092
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  • 5
    Digitale Medien
    Digitale Medien
    Localization of cells capable of transdetermination in a specific region of the male foreleg disk ofDrosophila (1977)
    Springer
    Development genes and evolution 182 (1977), S. 69-74 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Drosophila melanogaster ; Male foreleg disk ; Capacity of transdetermination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In the male foreleg disk ofDrosophila melanogaster the cells capable of transdetermination are clustered in a specific region within the upper half of the disk. Cells outside this region cannot transdetermine under any of the experimental conditions thus far applied. Transdetermination occurs when cells capable of transdetermination are stimulated to a certain extent of additional proliferation. This can be achieved either by exposing these cells at a wound surface of an intact fragment, or by dissociation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848088
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  • 6
    Digitale Medien
    Digitale Medien
    Localized synthesis of specific proteins during oogenesis and early embryogenesis inDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 151-165 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Oogenesis ; Embryogenesis ; Two-dimensional gels ; Protein synthesis ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Protein synthesis in egg follicles and blastoderm embryos ofDrosophila melanogaster has been studied by means of two-dimensional gel electrophoresis. Up to 400 polypeptide spots have been resolved on autoradiographs. Stage 10 follicles (for stages see King, 1970) were labelled in vitro for 10 to 60 min with35S-methionine and cut with tungsten needles into an anterior fragment containing the nurse cells and a posterior fragment containing the oocyte and follicle cells. The nurse cells were found to synthesize a complex pattern of proteins. At least two proteins were detected only in nurse cells but not in the oocyte even after a one hour labelling period. Nurse cells isolated from stages 9, 10 and 12 follicles were shown to synthesize stage specific patterns of proteins. Several proteins are synthesized in posterior fragments of stage 10 follicles but not in anterior fragments. These proteins are only found in follicle cells. No oocyte specific proteins have been detected. Striking differences between the protein patterns of anterior and posterior fragments persist until the nurse cells degenerate. In mature stage 14 follicles, labelled in vivo, no significant differences in the protein patterns of isolated anterior and posterior fragments could be detected; this may be due to technical limitations. At the blastoderm stage localized synthesis of specific proteins becomes detectable again. When blastoderm embryos, labelled in vivo, are cut with tungsten needles and the cells are isolated from anterior and posterior halves, differences become apparent. The pole cells located at the posterior pole are highly active in protein synthesis and contribute several specific proteins which are found exclusively in the posterior region of the embryo. In this study synthesis of specific proteins could only be demonstrated at those developmental stages which are characterized by the presence of different cell types within the egg chamber, while no differences were detected when stage 14 follicles were cut and anterior and posterior fragments analyzed separately. The differences in the pattern of protein synthesis by pole cells and blastoderm cells indicate that even the earliest stages of determination are reflected by marked changes at the biochemical level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848268
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  • 7
    Digitale Medien
    Digitale Medien
    Genetic analysis of pattern-formation in the embryo ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 249-268 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Pattern-formation ; Embryogenesis ; Maternal-effect mutants ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The mutationbicaudal (Bull, 1966) causes embryos to develop a longitudinal mirror image duplication of the posteriormost abdominal segments, while head and thorax are missing. These embryos occur with varying frequencies among eggs laid by mutant females, irrespective of the paternal genotype. Recombination and deletion mapping indicate thatbicaudal (bic) is a recessive, hypomorphic, maternal-effect mutation mapping at a single locus on the second chromosome ofDrosophila melanogaster close tovg (67.0±0.1). The frequency of bicaudal embryos depends on the age of the mother, her genetic constitution and the temperature at which she is raised. Best producers are very young females hemizygous forbic (bic/Df(2)vg B ) at 28° C. Under these conditions 80% to 90% of the eggs which differentiate can show the bicaudal embryo phenotype. Upon ageing of the mother the frequency of bicaudal embryos declines rapidly, and most of the eggs develop the normal body pattern. Temperature shift experiments suggest a temperature-sensitive period at the onset of vitellogenesis. The mutation causes several types of abnormalities in the segment pattern of theDrosophila embryo, which are interpreted as various degrees of expression of the mutant character. The most frequent abnormal phenotype is the symmetrical bicaudal embryo with one to five abdominal segments duplicated. Less frequent are asymmetrical types, in which the smaller number of segments is always in the anterior reversed part. Other phenotypes are embryos with missing or rudimentary heads, and embryos with irregular gaps in the segment pattern. In bicaudal embryos, the pole cells, formed at the posterior pole of the egg prior to blastoderm formation, are not duplicated at the anterior. The significance of thebicaudal phenotypes for embryonic pattern-formation inDrosophila is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00867325
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  • 8
    Digitale Medien
    Digitale Medien
    Detection of clones in the nervous system ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 165-169 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Clones ; Nervous system ; Shibire ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mitotic recombination was induced, by X-irradiation at the blastoderm stage, in flies heterozygous for one of the temperature-sensitive paralytic mutationsshibire andtp-2. The results show that these mutations can be used to detect the presence of clones in the central nervous system through the temperature-sensitive paralysis of individual legs. Mitotic recombination can also be used to examine the effects of these mutations in the peripheral nervous system; shibire is thus shown to affect the function of sensory neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848786
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  • 9
    Digitale Medien
    Digitale Medien
    Isozymic patterns and functional states of cell lines ofDrosophila melanogaster cultured in vitro. II (1976)
    Springer
    Development genes and evolution 180 (1976), S. 107-119 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Drosophila melanogaster ; Cell lines ; Isoenzymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Our previous isoenzyme investigation ofDrosophila melanogaster cell lines in vitro has been completed with twelve further enzyme systems. The “enzyme profiles” seem to be in good agreement with a previous hypothesis concerning the precise origin of these cell lines (probably from imaginal discs or nervous tissues). Our results have been summarized with reference to the biochemical genetic map ofDrosophila melanogaster in order to consider a possible functional organization of the genome.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848101
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  • 10
    Digitale Medien
    Digitale Medien
    A study of the female germ line in mosaics ofDrosophila (1978)
    Springer
    Development genes and evolution 184 (1978), S. 41-56 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Drosophila melanogaster ; Female germ line ; Mosaics ; Stem cell divisions ; Metafemale ; Sterility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Our report presents an analysis of the development and dynamics of the female germ line inDrosophila. Females were produced that were mosaic either for attached-X chromosomes $$(\widehat{XX})$$ and a ring-X (triplo-X-diplo-X), or for $$\widehat{XX}$$ and a marked Y-chromosome $$(\widehat{XX}/Y - \widehat{XX}/O)$$ . The germ-line and genitalia of these females were analysed by direct microscopic observation or by examination of the progeny. Eggs derived from triplo-X germ cells were hardly capable of supporting development, with most of the zygotes dying during embryonic development. The analysis of the germ line was therefore carried out mainly by direct observation of histochemically stained developing oocytes in the ovaries of mosaic females. The total germ cell population of both ovaries of a female was mosaic in 22–29% of the tested animals. From this frequency of mosaicism we estimated the number of functional primordial germ cells to be betwen 3 and 6 cells at the blastoderm stage. At this stage the cell lineages for the left and right ovary are not yet separated. The germ cell population of individual ovarioles was frequently mosaic which shows that the few stem cells in an ovariole are recruited as a group and are not clonal descendants of a single ancestor cell per ovariole. An analysis of the sequential pattern of oocyte-nurse cell cysts in mosaic ovarioles revealed that neighbouring cysts tend to be of the same genotype. This suggests that the stem cells of the adult ovaries preferentially divide in bursts, one of them giving rise to two, three and sometimes even more cystocytes in a row. In addition, the foci for lethality and sterility of the triplo-X condition were determined. Non-mosaic triplo-X females (metafemales) are hardly viable and invariably sterile. Using our mosaics, the focus forlethality could be mapped to a region very near the ventral prothoracic discs. The focus forsterility resides in the genitalia, since flies with triplo-X genitalia never laid any eggs, regardless of the genotype of their ovaries.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848668
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  • 11
    Digitale Medien
    Digitale Medien
    Rudimentary mutants ofDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 167-177 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Pyrimidine biosynthesis ; rudimentary mutants ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The X-linkedrudimentary (r) mutants ofDrosophila melanogaster are pyrimidine auxotrophs and require exogenous pyrimidines (Nørby, 1970; Falk, 1976). We have established a set ofrudimentary cell lines that are derived from embryos, homozygous for eitherr 1 orr 36. The enzymatic activities of the pyrimidine synthesizing enzymes were measured in the mutant lines. We have further investigated the nutritional requirements of the mutant cells in vitro by using a pyrimidine free culture medium. Ther 1 cell lines were found to express 3–7%dihydroorotase (DHOase) activity as compared to a wildtype cell line. Reducedaspartate transcarbamylase (ATCase) activity was measured in somer 1 cell lines whereas wildtypecarbamylphosphate synthetase (CPSase) activity is expressed in allr 1 cell lines. Ther 36 cell line expresses wildtype activity ofDHOase andCPSase. ATCase activity was found to be reduced to 10% of the wildtype activity. The mutant cell lines do not proliferate in pyrimidine free minimal medium and cell proliferation is obtained by the addition of crude RNA. Proliferation of ther 1 cells is restored by the supplementation of the minimal medium withdihydroorotate whereas proliferation of ther 36 cells is restored by supplementation with eitherdihydroorotate orcarbamylaspartate. The results demonstrate that therudimentary phenotypesr 1 andr 36 are expressed at the cellular level and that the two mutant cell types behave as cellular pyrimidine auxotrophs in vitro.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848269
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  • 12
    Digitale Medien
    Digitale Medien
    The effect of fat body on the differentiation in vitro of wing imaginal discs ofDrosophila melanogaster (1976)
    Springer
    Development genes and evolution 180 (1976), S. 73-77 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Ecdysones ; Imaginal discs ; Fat body ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The effect of suboptimal levels of α-ecdysone on the differentiation in vitro ofDrosophila melanogaster wing discs was enhanced by the addition of larval fat body to the cultures. However, similar experiments with β-ecdysome showed no enhancement. It is suggested that a partial conversion of α-ecdysone to β-ecdysone by the fat body may well account for these results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848885
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  • 13
    Digitale Medien
    Digitale Medien
    Developmental potentials of the cells of the male foreleg disc ofDrosophila (1977)
    Springer
    Development genes and evolution 181 (1977), S. 309-320 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Drosophila melanogaster ; Male foreleg disc ; Pattern regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. The developmental potentials of the four quadrants of the male foreleg disc ofDrosophila melanogaster were analysed by culturing excised quadrants for 3 days and 10 days in adult hosts prior to metamorphosis. 2. The cultured pieces underwent different types of pattern regulation in a circular direction. The upper medial piece was able to regenerate the missing structures of the disc, thus confirming the findings of earlier reports. The three remaining pieces could undergo pattern duplication in mirror-image symmetry. The lower medial piece revealed in addition a slight capacity for regeneration from the vertical cut surface. 3. The duplicating pieces differed markedly in their frequencies of pattern duplication: duplications occurred with very high frequencies in lower medial pieces, with intermediate frequencies in upper lateral pieces, and with very low frequencies in lower lateral pieces. 4. Both lower lateral and upper lateral pieces underwent a progressive loss of most markers with increasing culture time. 5. Claws were regenerated solely by upper medial pieces. 6. Transdetermined structures, too, were encountered only in upper medial pieces. 7. The results are discussed with respect to the two major current models of pattern regulation in imaginal discs, the “gradient model” and the “clock model”. 8. It is suggested that the differences in the frequencies of pattern duplication reflect the unequal spacing of circular positional values within the three duplicating quadrants. Under this assumption the data indicate a progressive decrease in the density of circular positional values with increasing distance from the upper medial quadrant of the disc.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848058
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  • 14
    Digitale Medien
    Digitale Medien
    Mitochondrial granules in chondrocytes (1969)
    Springer
    Calcified tissue international 3 (1969), S. 184-193 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Mitochondria ; Calcification ; Calcium ; Chondrocytes ; Growth plate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé Des cultures d'épiphyse prélevées sur des rats et des souris ont été étudiées sous le microscope électronique. Un profile de granules mitochondriques de densité électronique a été trouvé. Les chondrocytes dans la zone proliférative avaint peu de granules, alors que ceux des zones successives ont montré une augmentation progressive de leur nombre et densité jusqu'à ce que la zone de calcification provisoire ait été atteinte. Cette zone a montré une distribution périphérique de mitochondries et une réduction du nombre et de la densité des granules mitochondriques. Du calcium isotopique 47 a été utilisé autoradiographiquement pour déterminer la location de calcium dans ces cellules. Des grains ont été trouvés sur les membranes R.E. et sur la plupart des mitochondries. La preuve d'un profile de ces granules et de leur rapport spatial avec la face de minéralisation indique une action éventuelle de mitochondries dès le début de la calcification de la matrice.
    Kurzfassung: Zusammenfassung Epiphysekulturen von Ratten und Mäusen wurden unter dem Elektronenmikroskop untersucht. Ein Profil von mitochondrischen Körnchen mit elektronischer Dichte wurde gefunden. Chondrozyten in der Proliferationszone wiesen wenig Körnchen auf, während die der nachfolgenden Zonen allmählich an Zahl und Dichte zunahmen, bis die Zone der provisorischen Verkalkung erreicht wurde. Diese Zone zeigte eine periphere Verteilung der Mitochondrien und eine Abnahme in Zahl und Dichte der mitochondrischen Körnchen. Isotopes Kalzium 47 wurde autoradiographisch verwendet, um die Lage des Kalziums in diesen Zellen zu bestimmen. Körnchen wurden auf den E.R.-Membranen und auf einem Großteil der Mitochondrien gefunden. Der Nachweis eines Profils dieser Körnchen und ihres räumlichen Verhältnisses zur Mineralisierungsfläche weist auf einen möglich Einfluß der Mitochondrien mit Beginn der Matrixverkalkung hin.
    Notizen: Abstract Rat and mice epiphyseal growth plates were studied with the electron microscope. A gradient of mitochondrial electron-dense granules was found. Chondrocytes in the proliferative zone had few granules, while those of the succeeding zones showed a gradual increase in number and density until the zone of provisional calcification was reached. This zone showed a peripheral distribution of mitochondria and a decrease in the number and density of mitochondrial granules. Isotopic47calcium was used autoradiographically to determine the location of calcium in these cells. Grains were found over the endoplasmic reticulum membranes and over most mitochondria. The demonstration of a gradient of these granules and their spatial relation to the mineralization front suggests a possible involvement of mitochondria in the onset of matrix calcification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02058661
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  • 15
    Digitale Medien
    Digitale Medien
    Absence of mitochondrial terminal respiratory enzymes in cartilage matrix vesicles (1977)
    Springer
    Calcified tissue international 24 (1977), S. 37-39 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Cartilage ; Matrix vesicles ; Mitochondria ; Respiratory enzymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary This study attempted to detect evidence of mitochondrial terminal respiratory components in matrix vesicles isolated from rachitic rat tibial epiphyseal plates. Biochemical assays for cytochrome c oxidase, NAD isocitrate dehydrogenase, NADP isocitrate dehydrogenase and succinate-cytochrome c reductase were negative. Polarimetric determinations revealed that the addition of succinate to matrix vesicles in suspension did not cause any increase in oxygen utilization. Spectrophotometric tracings of deoxycholate-solubilized matrix vesicles showed no characteristic absorption peaks or maxima belonging to any of the cytochrome complex components. Attempts to prepare pyridine hemochromes of cytochrome prosthetic groups from the matrix vesicles were also unsuccessful. The above results indicate that key components of mitochondrial respiratory systems are not detectable in rachitic matrix vesicles. The results are compatible with the interpretation that such vesicles are not derived from mitochondria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223294
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  • 16
    Digitale Medien
    Digitale Medien
    Are mitochondria directly involved in biological mineralisation? (1969)
    Springer
    Calcified tissue international 3 (1969), S. 100-102 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Mitochondria ; Calcium ; Mineralisation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02058651
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  • 17
    Digitale Medien
    Digitale Medien
    A proposed cellular mechanism for calcium transport in the intestinal epithelial cell (1978)
    Springer
    Calcified tissue international 26 (1978), S. 71-79 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Absorption ; Calcium ; Mitochondria ; Intestinal epithelium ; Potassium-pyroantimonate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Intracellular transport of calcium from the apical to the basal-lateral region of the intestinal epithelial cell was invetigated in duodenum from normal fed, fasted, and calcium-loaded rats. The process was followed with time using electron microscopy with potassium pyroantimonate to precipitate calcium. The observations made were subjected to morphometric analysis. The specificity of the method was demonstrated in the villus cell by resistance to micro-incineration and by absence of deposits following exposure to EGTA. Using this method calcium was seen in cells from calcium-fed rats at the microvillus border, in the Golgi zone, and within the internal compartments of the mitochondria. In cells from fasted rats calcium was not seen. Mitochondria were found largely at the apex of the cell and were free of detectable calcium. By 5 min, in the cells of fasted rats given a calcium load, the calcium had reached the Golgi apparatus and the inner mitochondrial compartment. After 15 min mitochondria were heavily loaded with calcium and had moved to the basal region of the cell. These observations suggest that mitochondria play an important role in absorption of calcium and appear to transport this ion from the apex to the basal region of the cell where entry into the capillaries takes place.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02013237
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  • 18
    Digitale Medien
    Digitale Medien
    Mitochondria, calcification and waste disposal (1969)
    Springer
    Calcified tissue international 3 (1969), S. 363-365 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Calcification ; Mitochondria ; Protozoa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02058679
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  • 19
    Digitale Medien
    Digitale Medien
    Glyoxysomal and mitochondrial malate dehydrogenase of watermelon (Citrullus vulgaris) cotyledons (1977)
    Springer
    Planta 136 (1977), S. 211-220 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Citrullus ; Isoenzymes ; Malate dehydrogenase ; Enzyme subunits ; Mitochondria ; Glyoxysomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Molecular properties of the glyoxysomal and mitochondrial isoenzyme of malate dehydrogenase (EC 1.1.1.37; L-malate: NAD+ oxidoreductase) from watermelon cotyledons (Citrullus vulgaris Schrad.) were investigated, using completely purified enzyme preparations. The apparent molecular weights of the glyoxysomal and mitochondrial isoenzymes were found to be 67,000 and 74,000 respectively. Aggregation at high enzyme concentrations was observed with the glyoxysomal but not with the mitochondrial isoenzyme. Using sodium dodecyl sulfate electrophoresis each isoenzyme was found to be composed of two polypeptide chains of identical size (33,500 and 37,000, respectively). The isoenzymes differed in their isoelectric points (gMDH: 8,92, mMDH: 5.39), rate of heat inactivation (gMDH: τ1/2 at 40°C=3.0 min; mMDH: stable at 40°C; τ1/2 at 60°C=4.5 min), adsorption to dextran gels at low ionic strenght, stability against alkaline conditions and their pH optima for oxaloacetate reduction (gMDH: pH 6.6, mMDH: pH 7.5). Very similar pH optima, however, were observed for L-malate oxidation (pH 9.3–9.5). The results indicate that the glyoxysomal and mitochondrial MDH of watermelon cotyledons are distinct proteins of different structural composition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00385987
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  • 20
    Digitale Medien
    Digitale Medien
    Destruction and possible de novo synthesis of phytochrome in subcellular fractions of laminae from Avena sativa L. (1978)
    Springer
    Planta 141 (1978), S. 273-277 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Avena ; Etioplasts ; Mitochondria ; Phytochrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phytochrome was determined in etiolated laminae of Avena sativaL. either without pretreatment or after 5 min of red irradiation followed by different periods of darkness (0–24 h). At given intervals laminae were homogenized and phytochrome was determined spectrophotometrically in the total homogenate and in purified etioplasts and mitochondria. Enhanced specific activity of phytochrome was found in all fractions after the irradiation in comparison to dark controls. Phytochrome destruction was observed in all fractions at the beginning of the subsequent dark period. Whereas the homogenate and the mitochondrial fraction showed a continuous destruction so that phytochrome reached a level far below that in etiolated plants, the phytochrome level in the plastid fraction reacheda minimum at 2 h with a subsequent increase beyond the dark level. This increase was most pronounced between 4 and 8 h after the red irradiation. The results are discussed in terms of the destruction and possible de novo synthesis of phytochrome that may be different in mitochondria and plastids.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00388343
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  • 21
    Digitale Medien
    Digitale Medien
    Influence of bovine serum albumine on the proton conductance of potato mitochondria membranes (1979)
    Springer
    Planta 147 (1979), S. 122-126 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Mitochondria ; Proton conductance ; Serum albumin ; Solanum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Pulsed acid base titrations, according to the procedure of Mitchell and Moyle, have been carried out on potato mitochondria in the presence and absence of Bovine Serum Albumine (BSA). The rate of the pH decay is slower when BSA is present. The buffering capacities of the outer and inner phases, the t1/2 of the pH decay after an acid pulse and the proton conductance of the inner membrane have been measured. The results show that plant mitochondria are relatively impermeable to H+ and OH−, but leakier than animal mitochondria. This may be related to the lower respiratory control ratios generally found with plant mitochondria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00389511
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  • 22
    Digitale Medien
    Digitale Medien
    Control of mitochondrial activities by phytochrome during greening (1979)
    Springer
    Planta 147 (1979), S. 229-235 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Avena ; Greening ; Mitochondria ; Oxidative Phosphorylation ; Phytochrome ; Respiration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mitochondria isolated from 7-day old darkgrown Avena sativa L. (var. Arnold) laminae given 5 min illumination of red light, followed by varying lengths of darkness up to 3 h, showed at least a twofold increase in the rates of both NADH-dependent oxygen consumption and respiratory chain phosphorylation over those of mitochondria isolated from unilluminated tissue. Similar organelles, isolated from tissue given either far-red or red followed by far-red pretreatment, exhibited rates of both functions of between 25% and 75% below those of the mitochondria from unilluminated tissue. The induction-reversion criteria for phytochrome control of respiration and oxidative phosphorylation were satisfied under all experimental conditions during the greening process. Treatment with continuous far-red light, acting presumably through the ‘high irradiance’ reaction of phytochrome, served to disengage phytochrome activity from photosynthesis. The stimulation of oxidative phosphorylation still occurred under these conditions, slightly slower but much more prolonged in the absence of ATP from photophosphorylation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00388743
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  • 23
    Digitale Medien
    Digitale Medien
    Effect of temperature on the pathways of NADH-oxidation in broad-bean mitochondria (1979)
    Springer
    Planta 144 (1979), S. 359-365 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Mitochondria ; NADH oxidation ; Respiration (rotenone-resistant) ; Temperature activation ; Vicia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 1. Respiration rates of broad-bean (Vicia faba) mitochondria were studied as a function of temperature. Arrhenius plots of all membrane-bound enzymes, as obtained with saturating substrate concentrations, revealed a break in the lower temperature range. That break was considered to indicate a phase transition of membrane phospholipids, characteristic for chilling-sensitive plants. A second discontinuity at 30°C occurred only with activities linked to energy conservation. — 2. The activation energies for the oxidation of NAD+-linked substrates differ between states 3 and 4. State 3 respiration of NAD+-linked substrates is the result a superimposition of two branches of electron transport, which can be separated by different sensibilities to rotenone. A characteristic temperature dependency of the respiratory control, as well as a shift of the low temperature break in the Arrhenius plot toward a higher temperature after state 4 to state 3 transition, are calculated to be caused by the superimposition of the two branches. — 3. The temperature dependency of the oxidation of extra-mitochondrial NADH and of succinate differs remarkably from that of the oxidation of matrix-NADH. It has been concluded that the rotenone-resistant oxidation of matrix-NADH and the oxidation of external NADH are mediated via different pathways with individual regulation sites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00391579
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  • 24
    Digitale Medien
    Digitale Medien
    Post-meiotic nucleo-cytoplasmic interaction in Cosmos bipinnatus (1979)
    Springer
    Planta 145 (1979), S. 449-457 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Alternation of generation ; Cosmos ; Gametogenesis ; Mitochondria ; Nuclear envelope ; Organelle autonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An interaction involving the nuclear envelope and spherical double-membrane bound inclusions takes place in the cytoplasm of post-meiotic male microspores of Cosmos (tribe Heliantheae, sub-tribe Coreopsidinae). The identity of the spherical inclusions has yet to be fully established, but they closely resemble profiles elsewhere in the cytoplasm, themselves presumably derived from the mitochondrial population of the premeiotic pollen mother cells. Both the cytoplasmic and nucleaar-associated inclusions regularly contain a central ‘vesicle’, formed by an ingagination of their bounding membranes. The interaction, which occurs immediately prior to the deposition of the primexine of the pollen wall, involves the adhesion of the inclusions to the nuclear surface. Experiments with osmotically disrupted cells reveal that the inclusions are firmly bound to the envelope and, at the points of contact, electron opaque granules are regularly present. Frequently elements of the chromatin may be observed in juxtapostion to these points of contact, but on the inner face of the envelope. The interaction in Cosmos is proposed to constitute part of the process by which the cytoplasm and its content are realigned to the new “gametophylic” style of growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00380099
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  • 25
    Digitale Medien
    Digitale Medien
    Kinetics of mitochondrial phosphate transport and rates of respiration and phosphorylation during greening of etiolated Avena leaves (1979)
    Springer
    Planta 144 (1979), S. 325-332 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Avena ; Greening ; Mitochondria ; Phosphate transport ; Respiration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Using the technique of silicone oil filtration of organelles and the inhibitor stop method, the kinetics of transport of inorganic phosphate across the inner mitochondrial membrane were tested in relation to different stages of greening (0 to 24 h) of etiolated laminae of Avena sativa L., and compared to the rates of oxygen consumption and ATP formation. The results demonstrate that there is a pronounced increase in phosphate transport after 3 h of greening, reaching values for Vmax (about 17 μmol mg protein-1 h-1) that are three times as high as those measured with mitochondria from etiolated tissue. This is also mirrored by the rates of respiration and oxidative phosphorylation. After 24 h of light treatment (4 Klx), respiration and ATP formation, as well as V decreased again to levels below those of the etiolated stage. In contrast to V, there was no change in the affinity between inorganic phosphate and the binding sites of the transporting systems involved, as indicated by a rather constant Km (0.23 mM) for phosphate transport. Of the inhibitors of phosphate transport tested, mersalyl and methyl mercuric iodide were most efficient with identical characteristics of inhibition; but compared to animal mitochondria, the concentrations needed to result in similar amounts of inhibition, were more than ten times higher. The results are discussed with respect to plastid development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00391575
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  • 26
    Digitale Medien
    Digitale Medien
    Conjoined mitochondria and plastids in the barley mutant ‘albostrians’ (1979)
    Springer
    Planta 147 (1979), S. 178-179 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Hordeum ; Mitochondria ; Plastids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The intercalary meristem and surrounding tissues of the gene induced plastome mutant ‘albostrians’ of Hordeum vulgare L. were examined in the electron microscope for ultrastructural evidence of membrane continuities between plastids and mitochondria. In well developed tissues the ribosome-deficient plastids were usually in close proximity or appressed to mitochondria of normal appearance. In some sections through the meristemmatic region however the relationship between the two organelles was observed to be of a fused nature. These conjoinings are thought to be similar to those reported in normal living cells using cinephotomicrography but never before observed by transmission electron microscopy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00389522
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  • 27
    Digitale Medien
    Digitale Medien
    Characteristics of rotenone-insensitive oxidation of matrix-NADH by broad bean mitochondria (1978)
    Springer
    Planta 142 (1978), S. 83-90 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Mitochondria ; NADH oxidation ; Rotenone-resistant respiration ; Vicia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mitochondria from Vicia faba L. exhibit two pathways for the oxidation of endogenous NADH. One pathway is rotenone-sensitive and includes three phosphorylation sites, the other one is rotenone-insensitive and by-passes site I. This by-pass is located in the area of flavoproteins, but several lines of evidence suggest that the rotenone-insensitive oxidation of matrix-NADH is not mediated by the external NADH dehydrogenase. With saturating substrate concentrations the two pathways are superimposed in state 3 while in state 4 the electrons are transferred only via the by-pass. The rotenone-resistant electron flux is obviously regulated from the substrate side. We suggest that the function of the by-pass is to regulate the NADH/NAD+ ratio of the matrix space.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00385124
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  • 28
    Digitale Medien
    Digitale Medien
    Cytokinin inhibition of respiration by cells and mitochondria of soybean, Glycine max (L.) Merrill (1979)
    Springer
    Planta 146 (1979), S. 503-511 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Coumarate ; Cytokinin ; Glycine ; Respiration ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cells of a soybean tissue strain, suspended in an aerated liquid medium, caused disappearance of p-coumaric acid from the medium and oxidation of guaiacol, benzidine, pyrogallol, L-dihydroxyphenylalanine and L-epinephrine. Both the disappearance and the oxidations were inhibited by 6-benzylaminopurine (BAP) at a concentration of 0.5 mM. BAP at other concentrations either promoted or inhibited oxidation of epinephrine in precisely the pattern reported earlier for the disappearance of coumarate; therefore, the disappearance of coumarate probably involves its oxidation. The effectiveness of other cytokinins in inhibiting the oxidation was studied. At 0.5 mM, and perhaps even at 0.5 μM, some of the several cytokinins tested inhibited oxygen consumption by the soybean cells. This inhibition, which did not require any of the above metabolizable compounds, was especially marked in the presence of cyanide, azide or Antimycin A, and was detectable in 10 min or less. Either Antimycin A or salicylhydroxamic acid alone promoted O2 consumption but together they were quite inhibitory. The soybean cells apparently have an alternate respiratory pathway and cytokinins may influence its operation. Several cytokinins at 0.5 mM, and perhaps at 0.5 μM, also inhibited oxygen consumption by mitochondrial preparations from the soybean cells, the inhibition being evident in about 20 s. The consumption required a substrate such as malate, succinate or NADH. Cytokinins and related compounds varied in effectiveness as follows: BAP and 6-isopentenyla-minopurine ≥ 9-tetrahydropyranyl-BAP 〉 kinetin, ribosyl-isopentenylaminopurine, 9-methyl-BAP and 9-methoxymethyl-BAP 〉 6,6-dimethylaminopurine and zeatin (slight activity) 〉 6-methylaminopurine, nicotinamide and adenine (ineffective). To a great extent this order parallels the order of effectiveness of the compounds in causing cell division. Mitochondria, therefore, may contain a site for an important cytokinin action.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00380866
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  • 29
    Digitale Medien
    Digitale Medien
    Comments on the translational and transcriptional origin of Euglena chloroplastic aminoacyl-tRNA synthetases (1976)
    Springer
    Archives of microbiology 109 (1976), S. 201-203 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Euglena gracilis ; W3BUL ; Chloroplast ; Mitochondria ; Phenylalanyl-tRNA ; Synthetase ; Streptomycin ; Cycloheximide ; tRNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A response to: “A consideration of Euglena gracilis W3BUL as a cytoplasmic control for the wild-type phenylalanyl-tRNA synthetase system” and “A reinvestigation of the sites of transcription and translation of Euglena chloroplastic phenylalanyl-tRNA synthetase” by J. L. Lesiewicz and D. S. Herson.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00446628
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  • 30
    Digitale Medien
    Digitale Medien
    Non electrogenic function of the mitochondrial, alternative, cyanide-insensitive respiration in the yeast Saccharomycopsis lipolytica (1978)
    Springer
    Archives of microbiology 116 (1978), S. 297-302 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Cyanide-insensitive respiration ; Mitochondria ; ATP synthesis ; Proton translocation ; Exogenous NADH dehydrogenase ; Yeast ; Saccharomycopsis lipolytica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cyanide-insensitive mitochondria from Saccharomycopsis lipolytica possess an exogenous NADH dehydrogenase, located outside the inner mitochondrial membrane, and linked to coupling site II. These mitochondria are able to oxidize exogenous NADH via two pathways: (1) a cyanide- and antimycin-sensitive pathway, or cytochrome pathway, and (2) a cyanide- and antimycin-insensitive pathway, or alternative pathway. Although the oxidation of exogenous NADH through the cytochrome pathway occurs with an ATP/0 ratio tending to 2, it proceeds, per molecule of NADH oxidized, with the apparent ejection in the outer medium of only 3 protons instead of 4 protons, as is the case with glycerol 3-phosphate as control substrate, but leaves 1 hydroxyl ion in the outer medium after decay of the protonmotive force. These properties were used to demonstrate the non electrogenic function of the alternative pathway. Indeed, the oxidation of exogenous NADH via the alternative pathway proceeds without apparent ejection of protons, although this oxidation generates an electron flux in the alternative pathway as demonstrated by the net appearance in the outer medium of 1 hydroxyl ion per atom of oxygen reduced, appearance which proves sensitive to benhydroxamic acid, a specific inhibitor of the alternative pathway. The non electrogenicity of the alternative pathway is accompanied by the absence of ATP synthesis as expected from Mitchell's chemiosmotic model. The absence of energy conservation when the electron transfer proceeds via the alternative pathway is not the result of an uncoupling property of an active alternative pathway, as the oxidation of malate plus pyruvate via coupling site I and the alternative pathway occurs with an ATP/0 ratio tending to 1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00417855
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  • 31
    Digitale Medien
    Digitale Medien
    Influence of specific growth limitation and dilution rate on the phosphorylation efficiency and cytochrome content of mitochondria of Candida utilis NCYC 321 (1977)
    Springer
    Archives of microbiology 113 (1977), S. 65-72 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Candida utilis ; Continuous culture ; Mitochondria ; Oxidative phosphorylation ; Cytochromes ; Respiratory chain ; Potassium-limitation ; Sulphate-limitation ; Phosphate-limitation ; Magnesium-limitation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract With Candida utilis cells that had been removed directly from a 61 chemostat culture, in steady state, well-coupled mitochondria generally could be isolated. This required a modified snail-gut enzyme procedure that allowed the total processing time to be decreased to 3 h, or less. Examination of these mitochondria in an oxygraph showed the presence of 3 sites of energy conservation when the cells were grown at various dilution rates between 0.1 and 0.45 h-1 in environments that were, successively, glucose-, ammonia-, magnesium-, phosphate- and sulphate-limited. Potassium-limited cells also apparently possessed 3 sites of oxidative phosphorylation when growing at dilution rates greater than 0.2 h-1, but only 2 sites when growing at lower dilution rates. Analysis of cytochrome spectra obtained with these intact mitochondria revealed large quantitative (but not qualitative) differences, depending on the environmental conditions under which the yeast had been cultured. In particular, comparison of the ratio of cytochrome b to cytochrome a showed a pattern of change with dilution rate in mitochondria from potassium-limited cells that was distinctly different from those evident in mitochondria from cells that had been limited in their growth by the availability of other nutrients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00428582
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  • 32
    Digitale Medien
    Digitale Medien
    Changes in mitochondrial density and succinic dehydrogenase activity in Euglena gracilis as a function of the dependency on light for growth (1975)
    Springer
    Archives of microbiology 104 (1975), S. 233-236 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Euglena gracilis ; Mitochondria ; Repression ; Succinate Dehydrogenase ; Equilibrium Density
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mitochondria from Euglena gracilis strain z grown under strictly heterotrophic conditions have higher equilibrium densities and higher succinate dehydrogenase activities than those grown in the presence of light. There is a consistent trend toward lower mitochondrial density with increasing time of exposure to light. Experiments reported here indicate that the development of dependency upon light for the provision of energy results in the repression of mitochondrial development with respect to both density and enzymatic activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00447329
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  • 33
    Digitale Medien
    Digitale Medien
    Gametangial development in Allomyces macrogynus (1977)
    Springer
    Archives of microbiology 113 (1977), S. 173-179 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Phycomycete ; Allomyces ; Mitochondria ; Gametangial differentiation ; Sex ; Diaminobenzidine ; Cytochrome oxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The possible role of mitochondria in determining the sex of the gametangia of Allomyces macrogynus was investigated. Quantitative studies of mitochondrial distribution in vegetative hyphae confirmed previous reports of apical mitochondrial clustering. However, by the time the male and female gametangia were partitioned off, no significant difference in mitochondrial distribution between the two sexes was present. Possible mechanisms for the redistribution of mitochondria during early differentiation are discussed. In addition, cytochrome oxidase activity was demonstrated in all mitochondria of both male and female gametangia by the use of diaminobenzidine. It is concluded that neither mitochondrial distribution nor differential mitochondrial activity plays a determining role in the differentiation of the sexual cells in Euallomyces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00492021
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  • 34
    Digitale Medien
    Digitale Medien
    Nutritional control of xanthine dehydrogenase. II. Effects on xanthine dehydrogenase and aldehyde oxidase of culturing wild-type and mutant Drosophila on different levels of molybdenum (1975)
    Springer
    Biochemical genetics 13 (1975), S. 53-64 
    Details
    ISSN: 1573-4927
    Schlagwort(e): aldehyde oxidase ; xanthine dehydrogenase ; Drosophila melanogaster ; molybdenum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Two new mutants, deficient in aldehyde oxidase and xanthine dehydrogenase, have been isolated from a wild-type stock of Drosophila melanogaster and have been provisionally termed lxd c and lxd d, respectively, as both mutants appear to be allelic with lxd (low xanthine dehydrogenase). An analysis has been made of the effects of dietary molybdenum on lxd, lxd c, lxdd, lao (low aldehyde oxidase), mal (maroon-like eye color), and pac (Pacific) wild-type flies. On the lower dietary levels of 10 −3 M and 10 −2 M molybdenum, increases in specific activity of both enzymes were observed only in lxd. Furthermore, two- to three-fold increases in specific activity of both enzymes occurred in all strains, except mal, when cultured on 5×10 −2 M molybdenum. The lxd and lxd c strains failed to survive on this high concentration of the ion. Similar concentrations of molybdenum had no effect in vitro. An extra electrophoretic band of xanthine dehydrogenase was observed on polyacrylamide gel from extracts of wild-type flies cultured on certain levels of molybdenum, but its appearance was not always correlated with the increases in specific activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00486006
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  • 35
    Digitale Medien
    Digitale Medien
    The size of poly(A)-containing RNAs in Drosophila melanogaster embryos (1976)
    Springer
    Biochemical genetics 14 (1976), S. 357-371 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; poly(A)-containing RNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The size range of poly(A)-containing RNA from Drosophila melanogaster embryos has been estimated by hybridization with 3H-labeled poly(U) and subsequent fractionation on sucrose gradients. The median size of nuclear poly(A)-containing RNA is about 30 S (6000 nucleotides), and the median size of cytoplasmic poly(A)-containing RNA is about 17 S (1800 nucleotides). The relationship of these sizes to messenger RNA needed to code for protein and to the length of DNA contained in a chromomere is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484774
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  • 36
    Digitale Medien
    Digitale Medien
    Partial purification and properties of guanosine triphosphate cyclohydrolase from Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 259-270 
    Details
    ISSN: 1573-4927
    Schlagwort(e): GTP cyclohydrolase ; Drosophila melanogaster ; pteridines ; dihydroneopterin triphosphate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The first enzyme (named GTP cyclohydrolase) in the pathway for the biosynthesis of pteridines has been partially purified from extracts of late pupae and young adults of Drosophila melanogaster. This enzyme catalyzes the hydrolytic removal from GTP of carbon 8 as formate and the synthesis of 2-amino-4-hydroxy-6-(d-erythro-1′,2′,3′-trihydroxypropyl)-7,8-dihydropteridine triphosphate (dihydroneopterin triphosphate). Some of the properties of the enzyme are as follows: it functions optimally at pH 7.8 and at 42 C; activity is unaffected by KCl and NaCl, but divalent cations (Mg2+, Mn2+, Zn2+, and Ca2+) are inhibitory; the K m for GTP is 22 μm; and the molecular weight is estimated at 345,000 from gel filtration experiments. Of a number of nucleotides tested, only GDP and dGTP were used to any extent as substrate in place of GTP, and these respective compounds were used only 1.8% and 1.5% as well as GTP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484765
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  • 37
    Digitale Medien
    Digitale Medien
    The suppressor of forked mutation in Drosophila melanogaster: Interactions with the lozenge gene (1976)
    Springer
    Biochemical genetics 14 (1976), S. 611-617 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; phenol oxidases ; spectrophotometry ; electrophoresis ; suppression ; ribosomal proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract An interaction between the lozenge gene and the suppressor of forked gene of Drosophila melanogaster has been investigated both spectrophotometrically and electrophoretically. The nature of this interaction is such that certain lozenge alleles appear to be phenotypically suppressed while others are enhanced or unaffected, and the results reported demonstrate that the effect can clearly be observed at the biochemical level. Earlier observations have suggested that the suppressor of forked gene codes for a ribosomal protein, and this hypothesis is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00485839
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  • 38
    Digitale Medien
    Digitale Medien
    Selection against homozygotes in the ADH polymorphic system of Drosophila melanogaster associated with the lethal factor l(2) Stm (1977)
    Springer
    Biochemical genetics 15 (1977), S. 93-100 
    Details
    ISSN: 1573-4927
    Schlagwort(e): alcohol dehydrogenase (ADH) ; genetic polymorphism ; selection ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract In the natural populations +Tüb, +Prov, and +Rov, similar Adh F allele frequencies occur (q F=0.11, 0.18, and 0.08, respectively). However, there is a discrepancy in that the Adh F allele in +Tüb is closely linked to the lethal factor 1(2)Stm, which reduces relative fitness of the F phenotype to zero. In spite of this, polymorphism is maintained also in +Tüb, because the heterozygotes are superior to the homozygous S type (relative fitness=0.88). Under laboratory culture conditions, in +Tüb the relative fitness of the S genotype further decreases to 0.6. After outcrossing the lethal factor, relative fitnesses for S, FS, and F become 0.6, 1, and 0.48, respectively, implying that fitness for S remains the same. Relative values for S, FS, and F in +Prov, not affected by the lethal factor, are calculated by the maximum average fitness method to be 1, 1.2, and 0.2 under the assumption that heterozygous FS are similarly superior to S as in the natural +Tüb population and all allele frequencies found are stable equilibrium values.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484551
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  • 39
    Digitale Medien
    Digitale Medien
    Origin of α-glycerophosphate dehydrogenase isozymes in Drosophila melanogaster and their functional relationship in the α-glycerophosphate cycle (1977)
    Springer
    Biochemical genetics 15 (1977), S. 235-251 
    Details
    ISSN: 1573-4927
    Schlagwort(e): l-glycerol-3-phosphate dehydrogenase (α-GPDH) ; isozymes ; development ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The basis for the differentiation of l-glycerol-3-phosphate dehydrogenase (α-GPDH) into larval and adult isozymes in Drosophila melanogaster was investigated by the correlation of a lack of appearance of each isozyme during development within Drosophila bearing α-GPDH “null” alleles and by the study of a putative conversion factor. Conversion studies indicate the presence of a heat-labile RNase-resistant conversion factor present in crude larval extracts with the ability to convert GPDH-1 to GPDH-2 and GPDH-3 but not vice versa. In addition, “null” mutations at the Gpdh locus obliterate all isozymatic species of α-GPDH in all developmental stages. These observations suggest that all α-GPDH isozymes are the product of a single structural gene and that the multiple forms of this enzyme arise during successive developmental stages through an epigenetic modification of the primary Gpdh + polypeptide. Finally, observations are reported which bear on the functional divergence of the α-glycerophosphate cycle in the adult and larval stage of development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484456
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  • 40
    Digitale Medien
    Digitale Medien
    Isolation and genetic characterization of alcohol dehydrogenase thermostability variants occurring in natural populations of Drosophila melanogaster (1977)
    Springer
    Biochemical genetics 15 (1977), S. 971-988 
    Details
    ISSN: 1573-4927
    Schlagwort(e): allozymes ; thermostability ; alcohol dehydrogenase ; Drosophila melanogaster ; natural populations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Drosophila melanogaster collected from natural populations were examined fo thermostability variants within electrophoretic mobility classes of two enzymes. In alcohol dehydrogenase, two discrete forms of the “slow” allozyme and three discrete forms of the “fast” allozyme were revealed by postelectrophoretic treatments ranging from 15 sec at 40 C to 40 sec at 43 C. All variants have been mapped to within 0.7 unit of the Adh locus. Results of a geographic survey indicate that two alleles giving rise to fast-moderate and slow-moderate allozymes are common everywhere; other variants have a collective frequency ranging from 0% to 7%. In a test of the possibility that the rare Adh alleles could be generated by intragenic recombination between the two common alleles, electrophoresis and heat treatment of progeny recombinant for flanking markers of Adh revealed no new allozymes. Among 27 stocks containing slow α-glycerophosphate dehydrogenase allozymes and 109 fast stocks, heat treatments revealed no additional variation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00483992
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  • 41
    Digitale Medien
    Digitale Medien
    Control of drosopterin synthesis in Drosophila melanogaster: Mutants showing an altered pattern of GTP cyclohydrolase activity during development (1978)
    Springer
    Biochemical genetics 16 (1978), S. 13-26 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; GTP cyclohydrolase ; development ; pteridine biosynthesis ; mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The reaction catalyzed by GTP cyclohydrolase is the first unique step of pteridine biosynthesis in Drosophila melanogaster and is therefore likely to be an important control point. GTP cyclohydrolase activity varies during development, showing two distinct peaks of activity—one at pupariation and a much larger peak at emergence. Most of the early pupal enzyme is located in the body region, whereas in late pupal and early adult life most of the activity is found in the head. Mixing experiments indicate that developmental changes in activity are not due to changes in the level of a direct effector of GTP cyclohydrolase. The mutants raspberry and prune show an increased GTP cyclohydrolase activity at pupariation relative to wild type, but a decreased enzyme activity at emergence. The changes in GTP cyclohydrolase activity are reflected in changes in pteridine levels in these mutants. Several lines of evidence suggest that neither locus is the structural gene for GTP cyclohydrolase. The raspberry and prune gene products may play a specific role in regulating GTP cyclohydrolase activity during development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484381
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  • 42
    Digitale Medien
    Digitale Medien
    A genetic and developmental analysis of an acid deoxyribonuclease in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 1113-1134 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; isozymes ; position effect ; segmental aneuploidy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A deoxyribonuclease, called DNase-1, that is active at acid pH in the presence of EDTA has been studied in Drosophila melanogaster. The locus for the enzyme maps genetically to 61.8 on the right arm of the third chromosome. Cytogenetically, DNase-1 has been localized to within five to ten bands between 90C-2 and 90E. This analysis utilizes both electrophoretic variants and the Y-autosome translocations of Lindsley et al. (1972). DNase-1 is present in all stages of the life cycle, and the paternal genome actively contributes DNase-1 to the embryo between 0 and 1 hr after fertilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484532
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  • 43
    Digitale Medien
    Digitale Medien
    Variation in amount of enzyme protein in natural populations (1978)
    Springer
    Biochemical genetics 16 (1978), S. 159-170 
    Details
    ISSN: 1573-4927
    Schlagwort(e): alcohol dehydrogenase ; allozyme properties and amounts ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Among strains of Drosophila melanogaster each derived from a single fertilized female taken from natural populations, there is variation in both alcohol dehydrogenase (ADH) activity and the amount of ADH protein. The correlation between ADH activity and number of molecules over all strains examined is 0.87 or 0.96 in late third instar larvae depending on whether the substrate is 2-propanol or ethanol. With respect to the two common electrophoretic allozymic forms, F and S, segregating in these populations, the FF strains on the whole have higher ADH activities and numbers of ADH molecules than the SS strains. Over all strains examined, enzyme extracts from FF strains have a mean catalytic efficiency per enzyme molecule higher than that of enzyme extracts from SS strains when ethanol is the substrate, and much higher when 2-propanol is the substrate. One FF strain had an ADH activity/ADH protein ratio characteristic of SS strains.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484075
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  • 44
    Digitale Medien
    Digitale Medien
    Alcohol metabolism in Drosophila melanogaster: Uselessness of the most active aldehyde oxidase produced by the Aldox locus (1978)
    Springer
    Biochemical genetics 16 (1978), S. 203-211 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; alcohol tolerance ; alcohol utilization ; alcohol dehydrogenase ; aldehyde oxidase ; allozymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Alcohol dehydrogenase is necessary for ethanol detoxification and metabolic utilization. It has been generally assumed that aldehyde oxidase (AO) produced by the Aldox locus (3–56.7) is necessary for a further transformation of acetaldehyde into acetate. We find that various mutant strains (ma-l or Aldox n) which do not produce an active enzyme show about the same tolerance to alcohol as do wild strains. This physiological paradox is probably to be explained by the discovery of another locus (not localized) which produced a small amount of AO in all tested strains. The adaptive significance of the genetically polymorphic Aldox locus is probably to be looked for in physiological pathways other than ethanol metabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484078
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  • 45
    Digitale Medien
    Digitale Medien
    A simple approach for discovering common nonelectrophoretic enzyme variability: A heat denaturation study in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 299-305 
    Details
    ISSN: 1573-4927
    Schlagwort(e): nonelectrophoretic structural variability ; Drosophila melanogaster ; phosphoglucomutase ; genetic polymorphism ; heat denaturation study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A simple procedure is described to detect genetic heterogeneity within electrophoretic classes at a locus in Drosophila, based on electrophoresis and heat denaturation studies. Temperature-resistant (tr) and temperature-sensitive (ts) isoelectrophoretic alleles at the phosphoglucomutase locus (Pgm) are present at polymorphic frequencies in natural and in laboratory populations of Drosophila melanogaster.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484086
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  • 46
    Digitale Medien
    Digitale Medien
    Developmental changes of sepiapterin synthase activity associated with a variegated purple gene in Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 197-206 
    Details
    ISSN: 1573-4927
    Schlagwort(e): sepiapterin synthase ; variegation ; purple ; Drosophila melanogaster ; pteridine eye pigments ; drosopterin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A variegated position effect on the autonomous gene, purple, has been studied enzymologically in Drosophila melanogaster. Sepiapterin synthase, the enzyme system associated with pr +, was examined for activity in different developmental stages of the fly. The results indicate that T(Y:2) pr c5, cn/prc4 cn flies (flies in which pr + has been translocated and which exhibit variegation) have a reduced amount of enzyme activity as compared with both Oregon-R and pr 1 flies. This reduction in activity was not found in larval stages, which suggests that the inactivation process probably occurs in late larval or early pupal stages. The phenotype of the variegated adult has white eyes with red-colored spots and patches where drosopterins occur. The phenotype of the fly carrying the translocation is modified by the presence of additional Y chromosomes. This extends the observation from other systems that extra heterochromatin acts to suppress the variegated position effect. The advantages of studying the variegation by measuring enzyme activity, as well as the phenotypic expression, are several; for example, the developmental time at which variegation occurs may be estimated even though drosopterin synthesis is not occurring.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484485
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  • 47
    Digitale Medien
    Digitale Medien
    Polymorphism at the G6pd and 6Pgd loci in Drosophila melanogaster. III. Developmental and biochemical aspects (1979)
    Springer
    Biochemical genetics 17 (1979), S. 1131-1144 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; enzyme polymorphism ; G6PD ; 6PGD ; enzyme activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The electrophoretic variants of G6PD and 6PGD isolated from the Bogota Drosophila melanogaster population were characterized developmentally and biochemically. Changes in in vitro enzyme activity during development were comparable to those found for other dehydrogenases: an increase in the larval and adult stage and a decrease in the pupal stage. During the whole life cycle the “S” enzyme of both loci showed a higher activity than the “F” enzyme. MgCl2 had a stimulating effect on the activity of both enzymes whereas their heat stability was decreased. The allozymes of 6PGD had different Vmax's but were comparable with respect to Km values, pH optimum, and stability at 45 C. the allozymes of G6PD showed different Vmax's and differed in stability at 35 C, but had similar Km values and pH optima. As the difference in stability was probably due to differences in molecular structure of the allozymes, the differences in activity found at high pH and high MgCl2 concentration were most probably due to this difference in stability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00504350
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  • 48
    Digitale Medien
    Digitale Medien
    Transport defects as the physiological basis for eye color mutants of Drosophila melanogaster (1975)
    Springer
    Biochemical genetics 13 (1975), S. 603-613 
    Details
    ISSN: 1573-4927
    Schlagwort(e): transport mutants ; eye color mutants ; kynurenine ; Drosophila melanogaster ; Malpighian tubules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Kynurenine-H 3 transport and conversion to 3-hydroxykynurenine were studied in organ culture using the Malpighian tubules and developing eyes from wild type and the eye color mutants w, st, 1td, ca, and cn of Drosophila melanogaster. Malpighian tubules from wild type have the ability to concentrate kynurenine and convert it to 3-hydroxykynurenine. The tubules from w, st, 1td, and ca are deficient in the ability to transport kynurenine, as are the eyes of the mutants w, st, and 1td. This defect in kynurenine transport provides a physiological explanation for the phenotypic properties of the mutants. The relationship of these measurements to previous observations on these eye color mutants is discussed and the transport defect hypothesis is consistently supported. We have concluded that several of the eye color mutants in Drosophila are transport mutants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484918
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  • 49
    Digitale Medien
    Digitale Medien
    Correlation of guanosine triphosphate cyclohydrolase activity and the synthesis of pterins in Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 271-280 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; GTP cyclohydrolase ; pteridine biosynthesis ; development ; mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The enzyme guanosine triphosphate cyclohydrolase (GTP cyclohydrolase), which in bacteria is known to be the first enzyme in the biosynthetic pathway for the synthesis of pteridines, has been discovered in extracts of Drosophila melanogaster. Most of the enzyme (80%) is located in the head of the adult fly. An analysis of enzyme activity during development in Drosophila has revealed the presence of a relatively small peak of activity at pupariation and a much larger peak that appears at about the time of eclosion. Enzyme activity declines rapidly as the fly ages. Analyses for the production of the typical pteridine pigments of Drosophila have indicated that the small peak of GTP cyclohydrolase activity evident at pupariation coincides with the appearance of isoxanthopterin, sepiapterin, and pterin, and the larger peak at eclosion roughly corresponds to the accumulation of drosopterin as well as to the appearance in larger amounts of pterin and sepiapterin. These observations strongly suggest that in Drosophila, like bacteria, GTP cyclohydrolase is involved in the biosynthesis of pteridines. Analyses of a variety of zeste mutants of Drosophila melanogaster have shown that these mutants all contain GTP cyclohydrolase equal approximately to the amount found in the wild-type fly. These observations do not support the suggestions made by Rasmusson et al. (1973) that zeste is the structural locus for GTP cyclohydrolase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484766
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  • 50
    Digitale Medien
    Digitale Medien
    Genetics and physiological expression of β-hydroxy acid dehydrogenase in Drosophila (1978)
    Springer
    Biochemical genetics 16 (1978), S. 333-342 
    Details
    ISSN: 1573-4927
    Schlagwort(e): β-hydroxy acid dehydrogenase ; chromosome ; dosage compensation ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A mutant Had nl was induced in Drosophila melanogaster and found to be deficient in β-hydroxy acid dehydrogenase. This mutation was utilized to study the genetics and physiological expression of Had +. Had+ was mapped to the X chromosome at 54.4 and seems to be the structural gene for the enzyme. Enzyme activity in male and female flies indicates that the gene shows both dosage compensation independent from dose effect and differential activity during ontogeny. Electrophoretic mobility data indicate that the enzyme is a dimer which forms by random association of subunits. The fact that the mutant shows no detrimental effect implies that the enzyme is dispensable, at least under laboratory conditions. The biological and technical implications of this gene-enzyme system are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484089
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  • 51
    Digitale Medien
    Digitale Medien
    Dietary rescue of a lethal “null” activity allele of 6-phosphogluconate dehydrogenase in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 469-475 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; 6-phosphogluconate dehydrogenase ; Pgd n lethal alleles ; rescue by dietary supplements ; hexose monophosphate shunt
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The genetic rescue of Pgd n lethal alleles, accomplished by combining them with mutations lacking glucose-6-phosphate dehydrogenase activity, has led to the hypothesis that Pgd n lethality may be due to the accumulation of 6-phosphogluconate. In this article we report the rescue of Pgd n /Y males by dietary supplements (fructose and linolenate) designed to minimize 6-phosphogluconate production.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484212
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  • 52
    Digitale Medien
    Digitale Medien
    Biochemical properties of esterase 6 in Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 1-22 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; esterase 6 ; allozymes ; biochemical properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Biochemical properties of esterase 6 in Drosophila melanogaster were investigated using partially purified preparations from three genotypes, 1/1, 1/2, and 2/2. The molecular weight of the enzyme is estimated to be about 90,000, and treatment with sodium dodecylsulfate cleaves the enzyme into four units with a molecular weight of about 22,000. The activity toward 28 naturally occurring esters was assayed and shown to vary considerably with substrate, the 1/1 preparation having in general higher activity than 1/2 and 2/2, which were very similar. Heat sensitivity, the effect of metal ions, and the effects of the presence or absence of an end product were also studied. The differences demonstrated between allozymes would allow considerable scope, under appropriate conditions, for differential selection to operate between genotypes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484470
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  • 53
    Digitale Medien
    Digitale Medien
    Properties of the two common electrophoretic variants of phosphoglucomutase in Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 825-836 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; phosphoglucomutase ; polymorphism ; enzyme kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Phosphoglucomutase (PGM) of adult stage in Drosophila melanogaster has been characterized by gel filtration, ion-exchange chromatography, and isoelectric focusing. The two common electrophoretic variants, PGMA and PGMB, differ with respect to their kinetic and stability parameters. PGMA is more thermostable than PGMB but shows the same pH optimum, equal dependence on Mg2+, and identical molecular weight. There is no significant kinetic difference between the two allozymes at the optimum pH value, but at pH 6.0 the K m value for glucose-1,6-diphosphate of PGMB is significantly higher than that of PGMA. This difference might explain the observed selective advantage of the Pgm A allele in population studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00504306
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  • 54
    Digitale Medien
    Digitale Medien
    Biological role of alcohol dehydrogenase in the tolerance of Drosophila melanogaster to aliphatic alcohols: Utilization of an ADH-null mutant (1976)
    Springer
    Biochemical genetics 14 (1976), S. 989-997 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; alcohol dehydrogenase ; enzyme biological activity ; toxicity of alcohols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The toxicity of the first eight primary alcohols and of four secondary alcohols was compared in a wild-type strain (having active ADH) and an ADH-negative mutant. Differences between lc 50 measured in the two strains allowed an evaluation of the biological activity of the enzyme. In vitro, ADH is mainly active on secondary alcohols, while in vivo its main role is the detoxification and metabolism of ethanol. These observations suggest that originally ADH was involved in unknown metabolic pathways and that its utilization in ethanol metabolism could be a recent event.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00485131
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  • 55
    Digitale Medien
    Digitale Medien
    Preparation of specific antisera to Drosophila acid phosphatase without rigorous protein purification (1976)
    Springer
    Biochemical genetics 14 (1976), S. 237-243 
    Details
    ISSN: 1573-4927
    Schlagwort(e): null alleles ; antibody purification ; Drosophila melanogaster ; immunological methods
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Extracts from an acid phosphatase CRM− null mutant of Drosophila melanogaster were used to eliminate contaminating antibodies in a nonspecific preparation of anti-acid phosphatase serum. This method of producing specific antisera makes unnecessary the rigorous purification of an antigen prior to immunization attempts in those cases where CRM− null mutants of the antigen are available. Antisera so prepared could be used for a wide variety of purposes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484763
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  • 56
    Digitale Medien
    Digitale Medien
    Association and the Adh locus with a lethal factor (l(2) Stm) in Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 299-308 
    Details
    ISSN: 1573-4927
    Schlagwort(e): allozymes ; alcohol dehydrogenase ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Keeping Drosophila cultures at 28 C results in elimination of all minor multiple ADH bands, thought to be due to conformational change. Thus in diploid and triploid adults heterozygous for the Adh F and Adh Salleles, relative staining intensities are found for the three bands which were in conformity with the assumption that both alleles are equally expressed. Among all polymorphic strains derived from natural Central European and Mediterranean populations, the strain +Tüb is unique in that its Adh Fallele is closely linked to a new recessive lethal factor, named 1(2)Stm. All Adh F 1/AdhF 1 pupae are unable to emerge, and die. The lethal effect is obvious 50 hr earlier by retarded eye, bristle, and body wall pigmentation. Although all pupae of the phenotype F die, Adh F allele frequency scarcely seems to be lowered in this natural population.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484769
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  • 57
    Digitale Medien
    Digitale Medien
    Further evidence of thermostability variation within electrophoretic mobility classes of enzymes (1976)
    Springer
    Biochemical genetics 14 (1976), S. 383-387 
    Details
    ISSN: 1573-4927
    Schlagwort(e): allozymes ; thermostability ; alcohol dehydrogenase ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Two Drosophila melanogaster strains, each heterozygous for “fast” and “slow” alleles at the Adh locus, and each having balanced second chromosomes, were found to differ in the apparent thermostability of the slow allozyme. The two strains were crossed, and F1heterozygotes were separated on the basis of the origin of the slow allele. After electrophoresis, the cellulose acetate strips were treated 1 1/2 min at 35 C. The putatively more sensitive allozyme showed a strikingly greater response to heat. These findings further support the conclusion that electrophoretically cryptic allelic differences exist which are expressed in thermostability differences. Further application of this approach has revealed one similar sensitive slow allozyme and three cases of a relatively resistant fast ADH allozyme in wild-caught flies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484776
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  • 58
    Digitale Medien
    Digitale Medien
    Demonstration of 6-phosphogluconolactonase activity in Drosophila melanogaster using a null allele of 6-phosphogluconate dehydrogenase (1978)
    Springer
    Biochemical genetics 16 (1978), S. 1023-1029 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; 6-phosphogluconolactonase ; hexose monophosphate shunt ; Pgd n Zw n mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Using a double mutant strain, Pgd n Zw n , we have developed an assay for 6-phosphogluconolactonase activity and have demonstrated its occurrence in adult Drosophila melanogaster.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00483752
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  • 59
    Digitale Medien
    Digitale Medien
    Enumeration of Drosophila form II DNA-dependent RNA polymerase initiation sites on Drosophila DNA (1979)
    Springer
    Biochemical genetics 17 (1979), S. 97-104 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; form II RNA polymerase initiation sites ; chromomeres
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The in vitro incorporation of γ-32P-labeled nucleoside triphosphates into RNA by Drosophila melanogaster form II RNA polymerase from template sites which afford protection from the initiation inhibitor, polyriboinosinic acid (poly [I]), is used as a method for enumerating a specific class of transcription initiation sites on D. melanogaster DNA. Such sites number about 4000 per haploid genome for D. melanogaster. This value is in good agreement with the number of functional genetic units in the D. melanogaster genome as determined by classical cytogenetics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484476
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  • 60
    Digitale Medien
    Digitale Medien
    Purine transport by Malpighian tubules of pteridine-deficient eye color mutants of Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 565-573 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; Malpighian tubules ; purine transport ; eye color mutants ; riboflavin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Uptakes of guanine into Malpighian tubules of wild-type Drosophila and the eye color mutants white (w), brown (bw), and pink-peach (p p) have been compared. Tubules for each of these mutants are unable to concentrate guanine intracellularly. The transport of xanthine and riboflavin is also deficient in w tubules. The transport of guanosine, adenine, hypoxanthine, and guanosine monophosphate is similar in wild-type and white Malpighian tubules. These data and other information about these mutants make it likely that these pteridine-deficient eye color mutants do not produce pigments because of the inability to transport a pteridine precursor. This view supports the hypothesis that mutants which lack both pteridine and ommochromes do so because precursors to both classes of pigments share a common transport system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00498891
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  • 61
    Digitale Medien
    Digitale Medien
    Variants of α-glycerophosphate dehydrogenase in diploids and triploids of Drosophila melanogaster (1975)
    Springer
    Biochemical genetics 13 (1975), S. 263-271 
    Details
    ISSN: 1573-4927
    Schlagwort(e): allozymes ; α-glycerophosphate dehydrogenase ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract On the basis of band staining intensities in electrophoretic runs of single flies homozygous and heterozygous for two alleles at the autosomal locus for GPDH, F allele activity is believed to be 8% lower than S allele activity. Indeed, the intensity distribution in the patterns of FSS and FFS triploid females shows that both are not equally expressed. On a per fly or live weight basis, females with two and three doses of the Gpdh gene show bands with equal staining intensity, thus exhibiting a dosage effect when GPDH activity is estimated on a per cell basis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00486021
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  • 62
    Digitale Medien
    Digitale Medien
    Variation between electrophoretically identical alleles at the alcohol dehydrogenase locus in Drosophila melanogaster (1975)
    Springer
    Biochemical genetics 13 (1975), S. 721-731 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; enzyme variation ; alcohol dehydrogenase ; electrophoretically identical alleles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A new variant of alcohol dehydrogenase (ADH 71k) was found in a laboratory stock of Drosophila melanogaster. ADH in this stock had the same electrophoretic mobility as the F variant both on acrylamide and on agar. Activity levels were similar to the levels in F flies at temperatures between 15 and 25 C. But while ADH F enzyme is inactivated rapidly at 40 C, ADH 71k is still active. Also, ADH S is not inactivated at this temperature, but has a far lower activity per fly than ADH 71k. Genetic analysis showed that the new variant is an allele of the Adh locus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484929
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  • 63
    Digitale Medien
    Digitale Medien
    Isozyme variability in species of the genus Drosophila. VIII. The alcohol dehydrogenase polymorphism in north carolina populations of D. melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 47-58 
    Details
    ISSN: 1573-4927
    Schlagwort(e): electrophoresis ; alcohol dehydrogenase ; Drosophila melanogaster ; isozymes ; genetic variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Adult Drosophila melanogaster flies collected from populations broadly dispersed over ecological and geographic strata of North Carolina, and over a period of 4 years, were analyzed for alcohol dehydrogenase phenotypes by gel electrophoresis. Gene frequencies in spring-summer-fall field collections were remarkably stable over all strata. Two winter collections exhibited contrasting gene frequency changes. In one case the results are interpreted in terms of long-distance migration from Florida, while the other is explicable by assignment of a causal role to environmental factors which accompany the winter season.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484872
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  • 64
    Digitale Medien
    Digitale Medien
    Heat stability studies at the α-glycerophosphate dehydrogenase locus in populations of Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 769-775 
    Details
    ISSN: 1573-4927
    Schlagwort(e): hidden variation ; α-GPDH ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The level of hidden variation in populations of Drosophila melanogaster at the Gpdh + locus was determined by thermal stability studies of the protein. The results indicate a lack of variation using these methods both in and between the two common electrophoretic variants. It is suggested that α-GPDH is conserved in primary structure, which may be related to its critical role in flight muscle metabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484734
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  • 65
    Digitale Medien
    Digitale Medien
    Mutagenesis at the cinnabar locus in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 855-865 
    Details
    ISSN: 1573-4927
    Schlagwort(e): kynurenine hydroxylase ; cinnabar locus ; EMS mutagenesis ; Drosophila melanogaster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A study was undertaken to isolate mutations affecting the temporal appearance of kynurenine hydroxylase in Drosophila melanogaster. Such mutations, lacking or having reduced enzyme activity at the larval or pupal stage only, could represent changes in regulatory functions. Mutagenesis was carried out using EMS. Potential mutations were isolated from mass F1 cultures. The screening of large numbers of individuals was made possible by the use of the mutant red, which allowed visual classification for the presence or absence of the enzyme at both stages. From a series of six mutagenesis experiments 111,561 chromosomes were tested, and 122 phenotypically mutant F1 individuals were found. From these, 38 inheritable mutations were isolated which, by phenotypic observation, lacked or had reduced enzyme activity at the larval and pupal stages. Assay of enzyme activity levels in several of the mutants confirmed the phenotypic data. All of the 27 mutations that could be tested further are recessive and behave as cinnabar alleles. Complementation tests were performed between these 27 mutant stocks, and no complementation in the production of eye color has been seen between the mutants examined. When extended collection periods were used, a significantly higher percentage of inheritable mutations was isolated from the first 3 days of the screen. Over 80% of the F1 phenotypic mutants could be classified as mosaics, which indicates that cinnabar can be autonomous under certain conditions. The failure to isolate mutations in possible regulatory function is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00483738
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  • 66
    Digitale Medien
    Digitale Medien
    Isolation and biochemical analysis of a temperature-sensitive scarlet eye color mutant of Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 149-158 
    Details
    ISSN: 1573-4927
    Schlagwort(e): xanthommatin synthesis ; scarlet mutants ; Drosophila melanogaster ; temperature-sensitive mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Six new EMS-induced scarlet mutants were selected. Four of these were partially pigmented, with xanthommatin levels ranging from 12% to 45% of normal. In one (st 754ts), pigment production was temperature sensitive; the level of xanthommatin changed from less than 10% of normal at 29 C to more than 70% at 18 C. In all of the new mutants tested, the level of early pupal 3-hydroxykynurenine was as low as low as that in st 1. Thus reduced larval accumulation of this metabolite also appears to be a characteristic feature of scarlet mutants. Temperature-pulse and temperature-shift experiments were carried out with st 754ts to determine the temperature-sensitive period for the scarlet gene during development. The major sensitive period commenced prior to the onset of pigmentation and was over before adult emergence. Thus the initiation of xanthommatin synthesis is not brought about by the activation of the scarlet gene. In similar experiments carried out with a temperature-sensitive white mutant (w bl), a similar temperature-sensitive period was obtained.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00484480
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  • 67
    Digitale Medien
    Digitale Medien
    Partial purification and some properties of biopterin synthase and dihydropterin oxidase from Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 351-369 
    Details
    ISSN: 1573-4927
    Schlagwort(e): Drosophila melanogaster ; biopterin synthesis ; oxidation of dihydropterins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract An enzyme which has been named “biopterin synthase” has been discovered in Drosophila melanogaster. This enzyme, which has been purified 200-fold from extracts of Drosophila, catalyzes the conversion of sepiapterin to dihydrobiopterin, or oxidized sepiapterin to biopterin. The K m values for the two substrates are 63 µm for sepiapterin and 10 µm for oxidized sepiapterin. NADPH is required in this enzymatic reaction. An analysis of enzyme activity during development in Drosophila indicates a correlation between enzyme activity and biopterin content at various development stages. Another enzyme, called “dihydropterin oxidase,” was also discovered and partially purified. This enzyme catalyzes the oxidation of dihydropterin compounds to the corresponding pterin compounds. For example, sepiapterin (a dihydropterin) is oxidized to oxidized sepiapterin in the presence of this enzyme. The only dihydropterin that has been tested that is not a substrate for this enzyme is dihydroneopterin triphosphate, the compound thought to be a precursor for all naturally occurring pterins and dihydropterins. Since the action of dihydropterin oxidase is reduced significantly when the concentration of oxygen is very low, it is likely that this enzyme uses molecular oxygen as the oxidizing agent during the oxidation of dihydropterins. Neither NAD+ or NADP+ is required. In the presence of the two enzymes dihydropterin oxidase and biopterin synthase, sepiapterin is converted to biopterin. However, in the presence of biopterin synthase alone, sepiapterin is converted to dihydrobiopterin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00498975
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  • 68
    Digitale Medien
    Digitale Medien
    Structural and functional analysis of the scute locus in Drosophila melanogaster (1979)
    Springer
    Theoretical and applied genetics 55 (1979), S. 231-238 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Drosophila melanogaster ; Scute locus ; Maps ; Operon-like model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The functional expression of 12 scute alleles in homozygotes and compounds of Drosophila melanogaster at 14°, 22°, 30°C is analysed. Based on the data obtained, linear maps for bristles and mutations are built. The basic features of the maps, clustering and polarity, are invariable with respect to temperature, scute gene dosage and cross direction. In addition local dominance of the norm over bristle reduction was produced by the scute mutation; different types of complementation reactions were established for each bristle. The gene scute is treated as an operon-like system, composed of 3–4 cistrons with each controlling the formation of bristles on a particular region of the fly's body. This model argues well with the structure of maps constructed and implies a post-translational level of initial events of bristle-formation process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00268117
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  • 69
    Digitale Medien
    Digitale Medien
    An association between mitochondria and vesicles in smooth muscle (1975)
    Springer
    Cell & tissue research 161 (1975), S. 119-132 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Muscle, smooth ; Mitochondria ; Cell membrane, vesicles ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Two methods are described for measuring the mitochondrion-vesicle association seen by electron-microscopy in thin sections of the guinea-pig taenia coli. Both methods are based on comparisons of the observed distributions with predicted random distributions. It was found in control muscles that mitochondria were consistently nearer to vesicles than corresponding random points. 1 mM ouabain treatment reduced the mitochondrion-vesicle association for mitochondria which were closer to the membrane surface than 130 nm. Quantitative investigation of the freeze-etch structure of the membrane fracture faces is also reported, confirming the observation that membrane particles are more numerous in vesiculated membrane regions of smooth muscle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222118
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  • 70
    Digitale Medien
    Digitale Medien
    Glucose dependent alterations of mitochondrial ultrastructure and enzyme content in mouse pancreatic islets maintained in tissue culture (1975)
    Springer
    Cell & tissue research 162 (1975), S. 313-321 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Islands of Langerhans ; Mitochondria ; Enzymes ; Tissue Culture ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Isolated islets of Langerhans from mice were maintained in tissue culture for one week at either a high (28 mM) or a low (3.3 mM) extracellular glucose concentration. Electron microscopic morphometry by means of stereological methods revealed a much greater volume of mitochondria in islet cells cultured at low glucose than in those cultured at high glucose. The former islets also showed a higher activity of the mitochondrial marker enzyme, L-3-hydroxyacyl-CoA-dehydrogenase (E.C.1.1.1.35). These results indicate a true mitochondrial hypertrophy at the low glucose concentration. Although it is known from previous studies that the islet cell metabolism is diminished after low-glucose culture, the present observations of an increased mitochondrial volume probably do not reflect a degenerative process, but rather adaptive changes towards oxidation of energy yielding substrates other than glucose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220177
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  • 71
    Digitale Medien
    Digitale Medien
    Investigations on the turnover of adrenocortical mitochondria (1976)
    Springer
    Cell & tissue research 168 (1976), S. 1-9 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Mitochondria ; ACTH ; Stereology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of chronic administration of ACTH (up to 36 consecutive days) on the mitochondria of the zona reticularis of the rat adrenal cortex were investigated by stereologic techniques. It was found that ACTH induces two phases of hypertrophy of mitochondria alternating with two proliferative stages, which are associated with a significant decrease in the average volume of the organelles. It is suggested that, as in the zona fasciculata, ACTH controls the processes of growth and division of mitochondria in the zona reticularis. The mechanism underlying this action of ACTH as well as the differences between the responses to ACTH of the mitochondrial population of the two adrenal zones are discussed in the light of evidence indicating that mitochondria contain a complete genetic apparatus largely independent of nuclear control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219719
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  • 72
    Digitale Medien
    Digitale Medien
    Investigations on the turnover of adrenocortical mitochondria (1975)
    Springer
    Cell & tissue research 163 (1975), S. 273-290 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Mitochondria ; Dexamethasone ; DNA-synthesis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of chronic administration of dexamethasone (for up to 15 consecutive days) on both the morphology and DNA-synthesis of the mitochondria of the rat adrenal zona fasciculata were investigated by stereologic and autoradiographic techniques. Up to the 3rd day of continuous dexamethasone treatment, the average volume of mitochondria did not change, whereas the number of mitochondria per cell was significantly decreased. From the 3rd to the 15th day of hormonal administration both the volume and number of mitochondria were found to decrease in proportion to the duration of treatment. Autoradiography showed that after the 3rd day of dexamethasone administration there is virtually no incorporation of 3H-thymidine into the mitochondrial compartment. These findings are discussed in the light of evidence indicating that dexamethasone blocks ACTH-release by inhibiting the hypothalamo-hypophyseal axis. The results confirm the view that ACTH controls the maintenance of growth and proliferation of rat adrenocortical mitochondria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219464
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  • 73
    Digitale Medien
    Digitale Medien
    A light and electron microscope study of changes occurring at the cut ends following section of the dorsal roots of rat spinal nerves (1976)
    Springer
    Cell & tissue research 170 (1976), S. 491-505 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Axoplasmic flow ; Mitochondria ; Neurones, dorsal root ganglia ; Spinal nerve roots ; Synaptic vesicles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat dorsal spinal nerve roots were cut; 20 h later the axons in the vicinity of the cut were examined by light and electron microscopy. The changes in the cut tip distant from the ganglion were largely degenerative. On the ganglionic side of the cut a cap of free unmyelinated sprouts was formed. These sprouts contained clear and dense-core vesicles 40–150 nm in diameter, smooth endoplasmic reticulum and mitochondria. Some of the unmyelinated sprouts were extensions of myelinated axons, others arose from myelinated axons by lateral budding. In both myelinated and non-myelinated axons there was an accumulation of mitochondria, tubulo-vesicular smooth endoplasmic reticulum and large and small dense-core vesicles for a distance of approximately 500 μm behind the tip. Dense-core vesicles were more common in nonmyelinated axons than in their myelinated counterparts. In areas of intense accumulation the non-myelinated fibres were grossly swollen and distorted. The myelinated axons and some of the sprouts contained an unusual type of mitochondrion. The similarity between these sprouts and pre-synaptic terminals is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00361707
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  • 74
    Digitale Medien
    Digitale Medien
    Synaptology of the rat suprachiasmatic nucleus (1976)
    Springer
    Cell & tissue research 165 (1976), S. 509-544 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamus ; Suprachiasmatic nucleus ; Synapses ; Mitochondria ; Endoplasmic reticulum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Within the suprachiasmatic nucleus (SCN) of the rat the fine structure of the synapses and some features of their topological arrangement were studied. Five types of synapses could be distinguished with certainty: A. Two types of Gray-type-I (GTI) or asymmetrical synapses (∼33%). The presynaptic elements contain strikingly different types of mitochondria. Size of clear vesicles: ∼ 450 Å. Synapses with subjunctional bodies often occur, among these also “crest synapses”. Localization: dendritic shafts and spines, rarely somata. B. Three types of Gray-type-2 (GTII) or symmetrical synapses (∼66%)∶:1) Axo-dendritic and -somatic (=AD) synapses. Size of clear vesicles: ∼500 Å. 2) Invaginated axo-dendritic and -somatic (=IAD) synapses with club-like postsynaptic protrusions within the presynaptic elements (PreEl). Size of clear vesicles is very variable: ∼ 400–1,000 Å. 3) Dendro-dendritic, -somatic and somato-dendritic (=DD) synapses occurring at least partly in reciprocal arrangements. They represent an intrinsic system. Shape of clear vesicles: often oval; sucrose treatment partly produces flattening. Dense core-vesicles (dcv) are found in all GTII- and most of the GTI-synapses after three-dimensional reconstruction. All types of synapses (mostly GTII-synapses) can be enclosed by multilamellar astroglial formations. The synapses often occur in complex synaptic arrangements. Dendrites and somata of females show significantly more multivesiculated bodies than those of males. Further pecularities of presynaptic (PreEls) and postsynaptic elements (PostEls) within the SCN are described and discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224478
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  • 75
    Digitale Medien
    Digitale Medien
    Silicon-containing granules of rat liver, kidney and spleen mitochondria (1976)
    Springer
    Cell & tissue research 174 (1976), S. 315-327 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Silicon granules ; Mitochondria ; Rat liver ; Electron probe ; X-ray microanalysis ; 68Ge
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Isolated rat liver mitochondria containing granule aggregates (25–75 nm in diameter) and small (5–10 nm) electron opaque granules were examined by electron probe X-ray microanalysis. The granule aggregates gave an intense Si signal, while the small granules gave both Si and P signals. Isolated mitochondria of rat liver, spleen and kidney, subjected to detergent solubilization and differential centrifugation, produced two granule fractions: (1) a 10,000g fraction consisting predominantly of granule aggregates (25–75 nm) composed of smaller granules (5–10 nm in diameter), and (2) a 10,000–30,000 g fraction of non-aggregated small granules (5–10 nm). Thin sections of isolated granule aggregates gave Si X-ray signals similar to those obtained from in situ granules. In addition S, Cl, Mg, Cr and Fe X-ray signals were observed. Cr occurred only in the large kidney granules, while Fe occurred in both fractions of the spleen and kidney granules. The presence of Si in the granules was confirmed by chemical analysis of the isolated granules and in vivo radiolabeling of the granules with 31Si and 68Ge. Contamination within the electron microscope was eliminated by a liquid nitrogen anticontamination device.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220678
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  • 76
    Digitale Medien
    Digitale Medien
    Mitochondrial degeneration after organic phosphate poisoning in prosimian primates (1977)
    Springer
    Cell & tissue research 175 (1977), S. 459-465 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Mitochondria ; Degeneration ; Tricresylphosphate ; Lipofuscin ; Slow Loris (Nycticebus coucang coucang)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The degenerative reaction of mitochondria to tricresylphosphate (TCP) poisoning in spinal ganglion cells of Slow Loris (Nycticebus coucang coucang) were studied with the electron microscope. In neurones of animals treated with TCP, mitochondria display various stages of alterations which confirm mitochondrial involvement in TCP poisoning. The role of degenerated mitochondria in the formation of neuronal lipofuscin is discussed. It is suggested that the lipofuscin granule is a metabolic product inherently related to mitochondrial degeneration, irrespective of the primary cause: ageing or intoxication.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222412
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  • 77
    Digitale Medien
    Digitale Medien
    Giant nerve fibers in the ciliary muscle and iris sphincter of Macaca mulatta (1976)
    Springer
    Cell & tissue research 169 (1976), S. 33-40 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Nerve fibers ; Ciliary muscle ; Sphincter of the iris ; Mitochondria ; Glycogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Unusually large nerve processes, containing numerous mitochondria, glycogen particles, and synaptic vesicles are described in both the ciliary muscle and the iris sphincter muscle of the rhesus monkey. The striking similarity of these axonal profiles to the dendritic enlargements observed by Sotelo and Palay (1968) is noted and the possibility that they represent growing ends of peripheral nerve fibers is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219305
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  • 78
    Digitale Medien
    Digitale Medien
    The subcellular localization of calcium in vertebrate smooth muscle: Calcium-containing and calcium-accumulating structures in muscle cells of mouse intestine (1976)
    Springer
    Cell & tissue research 169 (1976), S. 221-231 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Smooth muscle ; Calcium ; Sarcoplasmic reticulum ; Mitochondria ; Microprobe analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The intracellular localization of calcium by means of cytochemical techniques was studied in smooth muscle cells of mouse intestine. When the lead acetate method according to Carasso and Favard (1966) was used calcium was found in mitochondria and sarcoplasmic reticulum and occasionally between the myofilaments. The active ATP-dependent accumulation of calcium into cell structures was investigated by the oxalate method (Heumann and Zebe, 1967). After appropriate treatment the only structures of smooth muscle cells which contained calcium oxalate (identified by microprobe analysis) were elements of the sarcoplasmic reticulum. The results are discussed in relation to the role of calcium in the control of muscle activity during the contraction-relaxation cycle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214210
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  • 79
    Digitale Medien
    Digitale Medien
    Variations in mitochondrial size and ultrastructure during germ cell development (1976)
    Springer
    Cell & tissue research 169 (1976), S. 531-550 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Germ cells ; Oogenesis ; Mitochondria ; Organelle differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Size variations and ultrastructural changes in mitochondria of developing germ cells of the female hamster were analyzed. Mitochondria in oogonia of foetus and newborn were elongate with transverse cristae. During pre-dictyate meiotic prophase they became small, rounded, and electron-dense with pleomorphic cristae. These changes were largely reversed when dictyate was reached. Maximum mitochondrial size and complexity of cristae were reached just at the beginning of the phase of rapid oocyte growth, and thereafter declined. As mitochondrial size and number of cristae decreased in the rapidly enlarging oocyte, the ratio of length to width increased, as did electron density of the matrix, until the formation of an antrum within the follicle. After antrum formation, the mitochondria again became more rounded and cristae were seldom seen. An attempt is made to correlate changes of mitochondrial morphology with other events occurring during oogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00218151
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  • 80
    Digitale Medien
    Digitale Medien
    The general occurrence of intramitochondrial crystals in Hydra cells (1976)
    Springer
    Cell & tissue research 171 (1976), S. 499-511 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Mitochondria ; Hydra ; Crystals ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Intramitochondrial crystals are found in normal Hydra as well as in animals undergoing various conditions (budding, regenerating, eserinetreated, and sexual). They appear in all regions of the animal, but seem to be more prevalent at or near the extremities: hypostome, tentacles and basal disk. They are found in all of the seven basic cell types: interstitial, cnidocyte, nerve, epithelio-muscular, gland, mucous and digestive cells. The chemical nature of the intramitochondrial crystals is unknown and their significance remains speculative.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220241
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  • 81
    Digitale Medien
    Digitale Medien
    Investigations on the turnover of adrenocortical mitochondria (1976)
    Springer
    Cell & tissue research 172 (1976), S. 149-156 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Mitochondria ; Ultrastructure ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The radioactivity decay of the mitochondrial compartment of 3H-thymidine-injected rats was followed by high resolution autoradiography. The number of days in which the radioactivity of the mitochondrial compartment is reduced to a half was calculated from the semilogarithmic plots of radioactivity versus time. Since DNA is a very stable molecule, it was assumed that this parameter can be an estimate of the half-life of adrenocortical mitochondria. It was found that the half-lives of mitochondria from the zonae glomerulosa, fasciculata and reticularis are, respectively, 8.20, 11.51 and 8.16 days.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226023
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  • 82
    Digitale Medien
    Digitale Medien
    Occurrence of oxyphil cells in suppressed parathyroid glands (1975)
    Springer
    Cell & tissue research 163 (1975), S. 465-470 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Parathyroid glands ; Oxyphil cells ; Mitochondria ; Mongolian gerbil ; Functional suppression, calcium accumulation ; Electron-microscopy, X-ray elemental analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Parathyroid glands from Mongolian gerbils cultured for 7 days at a high calcium concentration and examined by electron microscopy, were found to contain suppressed chief cells containing numerous mitochondria, and some oxyphil cells containing an abundance of medium-sized or large mitochondria with calcium-containing precipitates. It is suggested that parathyroid chief cells may be transformed into oxyphil cells, under certain conditions, and that the associated increase in the number and size of the mitochondria may be related to an intracellular accumulation of calcium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00218492
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  • 83
    Digitale Medien
    Digitale Medien
    Investigations on the turnover of adrenocortical mitochondria (1977)
    Springer
    Cell & tissue research 182 (1977), S. 145-150 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Human adrenal cortex ; ACTH ; Mitochondria ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of ACTH on the mitochondria of adult human adrenocortical cells cultured in vitro were investigated by electron microscopic and stereological methods. It was found that ACTH induces an increase in the volume of the mitochondrial compartment, which is due to both a hypertrophy and an increase in number of the organelles. The hypothesis that ACTH controls the growth and proliferation of human adrenocortical mitochondria is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220584
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  • 84
    Digitale Medien
    Digitale Medien
    Ultrastructural reactions of spinal ganglia to tri-ortho-cresyl-phosphate: Effects of neurotoxicity (1979)
    Springer
    Cell & tissue research 199 (1979), S. 409-414 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Spinal ganglion (domestic fowl) ; Tri-ortho-cresyl-phosphate ; Neurofilaments ; Endoplasmic reticulum ; Mitochondria ; Effects of toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of neurons in spinal ganglia of the domestic fowl poisoned with tri-ortho-cresyl-phosphate (TOCP) shows characteristic changes. The light neurons react to TOCP by a marked increase in the number of neurofilaments. These neurons also contain mitochondria in various degenerative stages. Several of the altered mitochondria show an increasing osmiophilia. Some of the darker neurons display a hypertrophy of the endoplasmic reticulum or a relative increase of neurofilaments. The mitochondria in some of these cells show early stages of degeneration. These changes appear 13 days after TOCP ingestion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236079
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  • 85
    Digitale Medien
    Digitale Medien
    Stereological analyses of the structure of mitochondria in pigeon skeletal muscle (1979)
    Springer
    Cell & tissue research 202 (1979), S. 493-503 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Stereology ; Surfaces ; Mitochondria ; Anisotropy ; Muscle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mitochondria in type-I and -II muscle fibres in the pectoralis major muscle of the pigeon (Columba livia) have been analysed using stereological techniques not previously applied in muscle biology. Mitochondrial volume fractions (VV) were estimated in different regions of each type of muscle fibre using randomly orientated sampling sectors within fibre profiles. These sectors were sub-divided into smaller sampling regions to provide accurate data on the intracellular distribution of mitochondria. Estimates of the external surface densities of mitochondria per unit volume of fibre, SV total surface , and also the densities of mitochondrial cristae, SV total cristae , were obtained using a specific technique derived for analysing anisotropic structures (Saltykov, 1958). The relative amounts of the random and orientated mitochondrial membranes were also estimated. Significiant differences were found to exist between the different types of muscle fibres and considerable though constant variations in the intracellular arrangement of mitochondria were also found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220440
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  • 86
    Digitale Medien
    Digitale Medien
    Further studies on the ring canal system of the ovarian cystocytes of Drosophila melanogaster (1969)
    Springer
    Cell & tissue research 102 (1969), S. 129-152 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Drosophila melanogaster ; Oogenesis ; Ring-Canal ; Cytokinesis ; Centriole
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An ultrastructural study was made of the ring canal system which connects the sister ovarian cystocytes that arise in the germaria of wild type Drosophila melanogaster females. It was discovered that during an oogonial mitosis both chromosomes and spindle are enclosed by a multilayered, perforated membrane system derived (at least in part) from the nuclear envelope. The cytokinesis of stem line oogonia takes place through the formation of a cleavage furrow. A second method of formation of plasma membrane is found in the case of cystocytes. It involves the production along the plane of division of a plaque of interconnected vesicles and tubules and later the coalescence of nearby tubules to form continuous sheets of membrane which segregate the cytoplasms of the sister cells. However, these remain connected by a canal which is enclosed by a ring-shaped rim that is completed prior to the plasma membrane to which the rim is subsequently attached. It is postulated that the rim represents a transformed midbody. As development proceeds the canal becomes wider, its rim becomes thicker, and the inner circumference of the rim becomes coated with a thick deposit having different cytochemical properties than the rim itself. Cystocyte divisions produce sister cells which differ in that one receives all previously formed canals; the other none. In the case of the last division (and perhaps in earlier ones as well) the sister cell receiving all previously formed canals also receives more cytoplasm than its sister. As the cells of the cluster grow, the canals remain close together. This finding suggests that when new plasma membrane is synthesized, it is added in areas remote from the canals. An investigation of the positioning in three dimensions of the fifteen canals of a newly formed, 16 cellcluster suggests that the spindles produced at one division are never parallel to those formed at the subsequent division. This continual shifting of the axes of the spindles at consecutive divisions presumably results in the branching chains of cells which characterize a cystocyte cluster. The possession of a unique pattern of cortical structures by two cystocytes is accompanied by the nuclear synthesis of synaptonemal complexes. The other fourteen cystocytes differentiate into nurse cells. In the most posterior portion of the germarium one of the two potential oocytes switches to the nurse cell developmental pathway. This “switched off” oocyte and the definitive oocyte grow at rates which differ greatly and are correlated to the amount of contact between their surfaces and certain follicle cells. As development proceeds centrioles accumulate in the oocyte, and most of these are thought to have been carried from the nurse cells into the oocyte in the nutrient stream.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336421
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  • 87
    Digitale Medien
    Digitale Medien
    On the development of midpiece mitochondria of mouse spermatozoa (1979)
    Springer
    Cell & tissue research 199 (1979), S. 349-352 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Spermatozoa ; Mitochondria ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary As seen by scanning electron microscopy, the mitochondrial helix in the developing midpiece of mouse testicular spermatozoa is dextral in direction and consists of spherical mitochondrial units arranged in an orderly array of four units per gyre: three appearing in face view and a fourth hidden from view at the back of the gyre. As the spermatozoa mature, the dextral helix is transformed into a sinistral helix. Its constituent spherical mitochondria either change direction abruptly without changing shape; or having first become semilunar or diamond-shaped, they change direction gradually. Mitochondrial division follows the change in helical pitch producing a double sinistral helix. The spherical (or semilunar/diamond-shaped) mitochondria presumably elongate to form the units of the mature midpiece.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236144
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  • 88
    Digitale Medien
    Digitale Medien
    Hypertrophic smooth muscle (1979)
    Springer
    Cell & tissue research 201 (1979), S. 79-92 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Smooth muscle ; Hypertrophy ; Caveolae ; Sarcoplasmic reticulum ; Mitochondria ; Intramembrane particles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cytological features of hypertrophic smooth muscle cells are investigated in the small intestine of the guinea pig in which a hypertrophy is induced by an experimental stenosis. By freeze-fracture the cell membrane appears richer in intramembrane particles than that of control muscle cells, whereas the number of caveolae per unit surface of cell membrane shows little or no change (16–19 caveolae μm−2). In the sarcoplasm there is a conspicuous increase of both smooth and rough sarcoplasmic reticulum; extent was measured by surface and by volume. Unusual forms of reticulum also appear. Mitochondria are reduced (in percentage volume) to about half the control value.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238049
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  • 89
    Digitale Medien
    Digitale Medien
    Direct connections between mitochondria and catecholamine-storage vesicles demonstrated by high voltage electron microscopy in rat adrenal medulla (1978)
    Springer
    Cell & tissue research 191 (1978), S. 421-432 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Mitochondria ; Catecholamine ; Storage vesicles ; Connections ; Adrenal medullary tissue ; High voltage electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Tubular channels from mitochondria to catecholamine-storage vesicles have been demonstrated in thick sections of adrenal medullary tissue from hypoglycemia-stressed rats by the use of the high voltage electron microscope. The function of these connections is not presently known although they may serve as channels for the transport of materials such as high-energy nucleotides from one organelle to the other. The present study has examined only the adrenal medulla, but it should be considered that such connections may also exist in other neural cells and possibly other cells in which there is intracellular transport of ATP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219806
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  • 90
    Digitale Medien
    Digitale Medien
    On the problem of counting and sizing mitochondria: A general reappraisal based on ultrastructural studies of mammalian lymphocytes (1979)
    Springer
    Cell & tissue research 204 (1979), S. 297-303 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Mitochondria ; Electron microscopy ; Stereology ; Number and volume ; Lymphocytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The authors ask the question whether the parameters “number” and “volume” are suitable for the morphometric analysis of mitochondria. In several types of cell, irregularity of mitochondrial shape makes it technically difficult, if not impossible, to obtain reliable stereological estimates of mean organelle volume or number per unit volume. Of more fundamental concern is whether number of mitochondria per cell is of any real value as a structural correlate of respiratory potential and hence as a measure of cell function. Alternative parameters might serve better for this purpose. Though the problem is illustrated by reference to quantitative studies of lymphocytes, it is also pertinent to the investigation of many other cell types.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234641
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  • 91
    Digitale Medien
    Digitale Medien
    Growth temperature acclimation byAmoeba proteus: Effects on cytoplasmic organelle morphology (1979)
    Springer
    Protoplasma 101 (1979), S. 23-35 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Amoeba proteus ; Cell cycle ; Golgi complexes ; Mitochondria ; Ribosomes ; Temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The effects on subcellular morphology of maintaining amoebae at temperatures other than 20
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01293432
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  • 92
    Digitale Medien
    Digitale Medien
    The absence of cytoplasm ribosomes on the envelopes of chloroplasts and mitochondria in plants: Implications for the mechanism of transport of proteins into these organelles (1979)
    Springer
    Protoplasma 100 (1979), S. 385-392 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Chlamydomonas ; Chloroplasts ; Mitochondria ; Protein transport ; Ribosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Chloroplasts and mitochondria ofChlamydomonas were examined by electron microscopy to determine if cytoplasmic ribosomes were associated with the envelopes of these organelles. Cells were treated with cycloheximide to prevent polypeptide chain completion, and resultant dissociation of envelope-ribosome associations. No extensive association of cytoplasm ribosomes with envelopes of chloroplasts, or mitochondria was detected in intact cells or in damaged cells in which cytoplasm was partly removed. Our results indicate that association of cytoplasm ribosomes with envelopes of chloroplasts or mitochondria is not an essential requirement for transport of polypeptides from cytoplasm to organelle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01279324
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  • 93
    Digitale Medien
    Digitale Medien
    The effects of anaerobiosis and metabolic inhibitors on mitochondrial ultrastructure inAmoeba proteus (1979)
    Springer
    Protoplasma 99 (1979), S. 275-288 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Amoeba proteus ; Anaerobiosis ; Metabolic inhibitors ; Mitochondria ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Anaerobiosis or exposure to the metabolic inhibitors potassium cyanide and Antimycin A produced changes in the form of living amoebae. These were accompanied by mitochondrial changes in fixed cells. Increasing the anaerobic period increased the percentage of mitochondria affected and resulted in a gradual reduction and eventual loss of the condensed Type I mitochondria ofAmoeba proteus. The rounder Type II mitochondria were not lost but underwent varying degrees of disruption, vesiculation of the cristae being evident after 5 hours exposures and matrical inclusions after 18 hours exposures. Similar cristal vesiculation was seen after 30 minutes treatments with potassium cyanide. Providing treatments were terminated before cell viability was lost, all mitochondrial abnormalities were reversible on return to normal culturing conditions. The longer the period of anaerobiosis the longer was the recovery time required for the return of normal mitochondrial structure and the re-equilibration of control Type I to Type II mitochondrial frequencies. The relationship between mitochondrial conformation and functional integrity is discussed in the light of these findings.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01275801
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  • 94
    Digitale Medien
    Digitale Medien
    Unusual mitochondrial ultrastructure in the pig adrenal cortex (1978)
    Springer
    Cell & tissue research 187 (1978), S. 129-134 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex (Pig) ; Mitochondria ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Unusually large mitochondria with few cristae were observed in the cells of the boundary layer between the zonae fasciculata and reticularis of the pig adrenal. These mitochondria occasionally contained parallel arrays of beaded filaments which appeared to be composed of repetitive electron opaque particles, measuring 10 to 11 nm in diameter. The possibility that these filaments are arranged in closely packed arrays of tubular structures with a central filament is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220624
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  • 95
    Digitale Medien
    Digitale Medien
    A chromosome substitution analysis of geotactic maze behavior inDrosophila melanogaster (1978)
    Springer
    Behavior genetics 8 (1978), S. 53-64 
    Details
    ISSN: 1573-3297
    Schlagwort(e): Drosophila melanogaster ; geotaxis ; chromosome analysis ; dominance effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Positive and negative geotactic maze behaviors were selected in strains of Drosophila melanogaster, for over 40 generations on 15-unit classification mazes. A chromosome substition analysis of these behaviors was undertaken to determine which of the three major chromosomes is most important in causing the differences in geotactic maze behavior between the divergent strains. By following the appropriate mating scheme, every possible homozygous chromosomal combination of the X, II, and III chromosomes from the geopositive and geonegative strain was produced. Heterozygous combinations were also produced to test for dominance and interchromosomal interactions. The results indicate that all three chromosomes are involved in geotactic behavior. The order of importance was II〉III〉X. Dominance effects were found in females for the X chromosome from the geopositive strain and for the III chromosome from the geonegative strain. No evidence for interchromosomal interactions was uncovered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01067704
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  • 96
    Digitale Medien
    Digitale Medien
    Genetic analysis of phototaxis near the upper limit of the visual spectrum ofDrosophila melanogaster (1979)
    Springer
    Behavior genetics 9 (1979), S. 123-128 
    Details
    ISSN: 1573-3297
    Schlagwort(e): Drosophila melanogaster ; phototaxis ; X chromosome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Strains ofDrosophila melanogaster differ in their phototactic responses to red light (654 nm). Genes located on all three major chromosomes are involved in influencing the response, but the X chromosome and third chromosome account for most of the variation in phototaxis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01074331
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  • 97
    Digitale Medien
    Digitale Medien
    Relationship between larval feeding behavior and viability inDrosophila melanogaster andD. simulans (1979)
    Springer
    Behavior genetics 9 (1979), S. 129-134 
    Details
    ISSN: 1573-3297
    Schlagwort(e): Drosophila melanogaster ; D. simulans ; larval feeding behavior ; egg-to-adult viability ; isofemale line
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Larval feeding behavior of isofemale lines of the sibling speciesDrosophila melanogaster andD. simulans was investigated. This behavior was measured as the number of cephalopharyngeal retractions of individual larvae per 30 sec period (CPR score) in different generations (G0, G1, and G14). In addition, egg-to-adult viability was estimated in each isofemale line. The results were as follows: (1) In either species, there was variation of CPR score among individuals and among isofemale lines. Although no differences of CPR score were found among experimental groups (generations) and between species, there was a significant difference among isofemale lines. (2) The behavioral trait was stable through generations in each isofemale line. (3) This behavior was correlated with egg-to-adult viability, showing that it is important for the development of the fly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01074332
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  • 98
    Digitale Medien
    Digitale Medien
    A survey of intra -and interspecific variation for pupation height inDrosophila (1979)
    Springer
    Behavior genetics 9 (1979), S. 209-217 
    Details
    ISSN: 1573-3297
    Schlagwort(e): Drosophila melanogaster ; D. simulans ; D. pseudoobscura ; pupation height ; geotaxis ; species differences ; selection for pupation height
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Pupation heights of various natural and laboratory populations ofDrosophila melanogaster, D. simulans, andD. pseudoobscura were observed in the laboratory under conditions of continuous darkness or continuous light. Generally higher mean pupation heights were observed under conditions of darkness.D. melanogaster tended to pupate higher than theD. pseudoobscura populations, andD. pseudoobscura tended to pupate higher thanD. simulans. The order of these species differences was similar whether pupation was measured in light or in darkness. Results of selection for pupation height inD. melanogaster suggest the presence of genetic variation for this character. The possibility that a relationship exists between adult and larval behaviors was explored by measuring the pupation heights of larvae from strains selected for geotactic behavior as adults, and also by measuring geotaxis of adults from strains selected for pupation height.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01071301
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  • 99
    Digitale Medien
    Digitale Medien
    Genetic and behavioral studies of female sex appeal inDrosophila (1979)
    Springer
    Behavior genetics 9 (1979), S. 257-275 
    Details
    ISSN: 1573-3297
    Schlagwort(e): sexual behavior ; Drosophila melanogaster ; genetic mosaics ; ontogeny of behavior ; wing vibration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The sex appeal of aDrosophila melanogaster female is defined here as the stimulus (or set of stimuli) which induces wing vibration in courting males. A quantitative measure of sex appeal is the cumulative duration of wing vibration induced by a given female averaged over several consecutive test intervals using different standardized male testers (sex appeal parameter, SAP). By use of SAP, both males and females are found to have the same amount of sex appeal on the first day after eclosion. However, males rapidly lose it by the next day, so that mature males become distinct from females. We report the ontogeny of the male's response to sex appeal. By the SAP method, we also demonstrate that the male's response is dependent on his previous encounter with females. The sex appeal of 287 gynandromorphs was examined in order to localize the sex appeal focus by means of blastoderm fate mapping. Most mosaic flies were classified as either positive (femalelike, with high SAPs) or negative (malelike, with SAPs of zero). Sixteen percent of the gynandromorphs had intermediate levels of SAP, inducing only short vibrations, a response which males rarely give to normal females. Assuming that the gynanders with such intermediate sex appeal must have both female and male foci, distances to the foci from external landmarks were calculated. The center of the focus seems to be an internal structure mapping to the ventroposterior region of the blastoderm fate map, close to the primordia of the anterior sternites. The focus might include a large mesodermal area, but only part of it must have a female genotype for the sex appeal to be expressed. A possible involvement of the fat bodies in production of the sex appeal stimulus is discussed in relation to these findings. Consistent with this conclusion is the fact that females whose abdomens were amputated still retain enough sex appeal to induce male wing vibrations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01068205
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Genetic basis of aristal morphology inDrosophila melanogaster and its correlation with behavior: Selection for increased and decreased aristal branching (1979)
    Springer
    Behavior genetics 9 (1979), S. 297-308 
    Details
    ISSN: 1573-3297
    Schlagwort(e): aristal morphology ; Drosophila melanogaster ; artificial selection ; geotaxis ; mating behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The aristae ofDrosophila have been shown to play a role in mating behavior and geotaxis. Two populations ofD. melanogaster were selected for increased and decreased numbers of major aristal branches. Selection was successful and resulted in two lines differing by an average of six aristal branches. Hybridization analyses of selected lines revealed that genes influencing aristal branching are located on both the X chromosome and the autosomes. Polygenic control of aristal morphology is indicated by a gradual response to selection and low realized heritabilities. When selection was relaxed for 19 generations, the number of aristal branches did not revert to the number in the control line. Changes in aristal branching did not appear to have a consistent influence on geotaxis, although there was a tendency for flies with fewer aristal branches to be geonegative. Neither mating speed nor ethological isolation between the two populations was affected by selection. It is concluded that the number of aristal branches inDrosophila is a neutral trait (i.e., not subject to natural selection) under laboratory conditions. Correlations between aristal morphology and behavior found in other selection experiments by previous investigators were likely due to linkage disequilibria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01068208
    Standort Signatur Erwartet Verfügbarkeit
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