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  • Drosophila  (116)
  • Calcium  (98)
  • Springer  (214)
  • Annual Reviews
  • 1980-1984  (214)
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  • 1
    Electronic Resource
    Electronic Resource
    Evidence for myosin heterogeneity inDrosophila melanogaster (1981)
    Springer
    Development genes and evolution 190 (1981), S. 297-300 
    Details
    ISSN: 1432-041X
    Keywords: Myosins ; Drosophila ; muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electrophoresis of myosin extracts from larvae and adult tissues ofDrosophila melanogaster under non-dissociating conditions indicate that two of the bands seen are myosins. They stain for Ca2+ ATPase activity and when cut and re-run under dissociating conditions are found to contain a myosin heavy chain that co-migrates with rabbit skeletal muscle myosin heavy chain. One of the forms of myosin seen is found primarily in extracts from the leg. The other is common to the adult fibrillar flight muscles and the larval body wall muscles. The electrophoretic evidence for two myosin types is strengthened by the histochemical demonstration of two myofibrillar ATPases on the basis of their lability to acid or alkali preincubation. The myofibrillar ATPase in the leg and the Tergal Depressor of the Trochanter (TDT) are shown to be relatively acid labile and alkali stable. The larval body wall muscles and the adult fibrillar flight muscles have an ATPase which is acid stable and alkali labile. This distribution of the two myofibrillar ATPase coincides with that predicted by electrophoresis of extracts from whole tissue and also locates the two myosins to specific muscle types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848758
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  • 2
    Electronic Resource
    Electronic Resource
    Drosophila melanogaster eggshell development: Localization of the s19 chorion gene (1981)
    Springer
    Development genes and evolution 190 (1981), S. 301-303 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Geographic strains ; Chorion genes ; Electrophoretic variants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Further IF screening ofDrosophila melanogaster geographic strains has revealed a variant of the s19 major chorion protein. Developmental analysis of F1 hybrids indicates that the source of the variation is found in the structural gene for this protein. The linkage group of the variant gene was determined to be the third, and the gene was localized by several methods of recombination analysis. The s19 gene was found to be tightly linked to thesepia locus, as had been previously found for the s18 gene (Yannoni and Petri 1980). Lack of recombination between the s19 and s18 genes in double heterozygotes suggested that these two genes are within 0.3 map units of each other. Although more precise localization of the s19 gene failed, the s18 gene could be more specifically located to the right ofsepia, betweensepia andhairy. Contrary to our prediction (ibid.), the s19 and s18 genes have been found to be tightly linked in spite of the fact that they display somewhat different developmental stage specificity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848759
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of the l(1)su(f)ts67g mutation ofDrosophila melanogaster on glue protein synthesis (1981)
    Springer
    Development genes and evolution 190 (1981), S. 308-312 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; ts-Suppressor mutant ; Glue proteins ; Intermolt puffs ; Electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The l(1)su(f)ts67g mutation has been shown to suppress the developmentally regulated expression of glue protein genes at 30°C. Transferring mutant larvae to the restrictive temperature before the end of the second larval instar results in the absence or extreme reduction of glue protein synthesis while general protein synthesis is unaffected. At the same time, the three glue protein correlated chromosomal regions 3C, 25B, and 68C continue to show prominent puffs. The results suggest that the mutation may be affecting the processing or translatability of specific mRNAs rather than the translational machinery itself.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863267
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  • 4
    Electronic Resource
    Electronic Resource
    A cell arrangement specific to thoracic ganglia in the central nervous system of theDrosophila embryo: Its behaviour in homoeotic mutants (1981)
    Springer
    Development genes and evolution 190 (1981), S. 370-373 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Homoeotic mutants ; Ventral cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We describe a set of cells in the central nervous system of theDrosophila embryo which are restricted to the thoracic ganglia in the wildtype. Taking these cells as indication of thoracic identity, we find that the ventral cord of embryos homozygous mutant for different bithorax functions and for Polycomb undergoes homoeotic transformations equivalent to those observed in the larval cuticle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863276
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  • 5
    Electronic Resource
    Electronic Resource
    Dicephalic — ADrosophila mutant affecting polarity in follicle organization and embryonic patterning (1982)
    Springer
    Development genes and evolution 191 (1982), S. 28-36 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Polarity ; Maternal effect ; Nurse cells ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationdicephalic (dic) affects follicle development and thereby alters the antero-posterior polarity of embryonic patterning. It maps at a single locus (3–46.0±1.0) and can be characterized as a semi-dominant maternal effect mutation with low penetrance. Indic follicles, the 15 nurse cells form two clusters located at opposite poles of the oocyte; the numerical distribution of the nurse cells among the clusters varies from 7:8 to 1:14. Thedic egg shell carries a micropyle (anterior marker) at either pole, but the misshapen respiratory appendages are restricted to one of the two poles in most eggs. The malformed eggs rarely yield larvae and these are always abnormal anteriorly and/or posteriorly. The segment pattern expressed in their cuticle may represent two anterior parts of opposite polarities (double head type), two posterior parts of opposite polarities (double abdomen type, rare) or show uniform polarity. Lability of organization at the cystocyte stage appears as the primary developmental defect of the mutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848543
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  • 6
    Electronic Resource
    Electronic Resource
    Development of imaginal discs from lethal hybrids betweenDrosophila melanogaster andDrosophila mauritiana (1983)
    Springer
    Development genes and evolution 192 (1983), S. 48-50 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Hybrid lethality ; Imaginal discs ; Interspecific transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Females ofDrosophila melanogaster, crossed with males ofDrosophila mauritiana, produce only female offspring. The male hybrid larvae grow very slowly, fail to pupate and die after prolonged larval life. Imaginal discs from these male hybrids transplanted into Drosophila melanogaster larvae can give rise to adult structures with normal patterns. Differentiation of hybrid imaginal disc tissue is improved by short term culture in non-hybrid larvae prior to metamorphosis, suggesting that the hybrid larval haemolymph is inadequate to sustain normal imaginal disc growth. This may represent the physiological basis of the reproductive isolating mechanism separating the twoDrosophila species
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848770
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  • 7
    Electronic Resource
    Electronic Resource
    On the phenotype and development of mutants of early neurogenesis inDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 62-74 
    Details
    ISSN: 1432-041X
    Keywords: Early neurogenesis ; Neurogenic mutants ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The central nervous system (CNS) ofDrosophila develops from precursor cells called neuroblasts. Neuroblasts segregate in early embryogenesis from an apparantly undifferentiated ectoderm and move into the embryo, whereas most of the remaining ectodermal cells continue development as epidermal cell precursors. Segregation of neuroblasts occurs within a region called the neurogenic field. We are interested in understanding how the genome ofDrosophila controls the parcelling of the ectoderm into epidermal and neural territories. We describe here mutations belonging to seven complementation groups which effect an abnormal neurogenesis. The phenotypes produced by these mutations are similar. Essential features of these phenotypes are a conspicuous hypertrophy of the CNS accompanied by epidermal defects; the remaining organs and tissues of the mutants are apparently unaffected. The study of mutant phenotype development strongly suggests this phenotype to be due to misrouting into the neural pathway of development of ectodermal cells which in the wildtype would have given rise to epidermal cells, i.e. to an initial enlargement of the neurogenic region at the expense of the epidermogenic region. These observations indicate that the seven genetic loci revealed by the mutations described in this study contribute to control the neurogenic field. The present results suggest that in wildtype development neurogenic genes are supressed within all derivatives of the mesoderm and endoderm and some derivatives of the ectoderm, and conditionally expressed in the remaining ectoderm. The organisation of the neurogenic field in the wildtype is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848482
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  • 8
    Electronic Resource
    Electronic Resource
    Characterization by isoelectric focusing of chorion protein variants inDrosophila melanogaster and their use in developmental and linkage analysis (1980)
    Springer
    Development genes and evolution 189 (1980), S. 17-24 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Geographic strains ; Chorion proteins ; Electrophoretic variants ; Chorion gene linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drosophila melanogaster chorion proteins are characterized on one-dimensional isoelectric focusing (IF) gels. The six major chorion components previously identified on SDS gels are shown to resolve into at least 11 components in our IF system. IF screening of 102 geographic strains ofDrosophila melanogaster revealed seven cases of variation in major chorion components. Two strains, Crimea and Falsterbo, which were monomorphic for a variant B1 protein and two strains, Skafto and Lausanne, which were monomorphic for a variant C1 protein, were chosen for further study. After IF developmental analysis of F1 hybrids had indicated that the sources of the variation resided in the structural genes for these proteins, each variant was crossed to a multiply marked and inverted strain (BLT) to determine the linkage group of the variant gene. To localize genes to more specific sites multiply marked 3rd (SKERO) or X-chromosomal (CB1) (X-PLE) mapping strains were used. In both Crimea and Falsterbo the gene for the B1 protein is located near map location 26 on the 3rd chromosome. In both Lausanne and Skafto the C1 gene is located on the X chromosome. Hence, for the first time, we have demonstrated genetically the non-linkage of two chorion genes, B1 and C1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848563
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of the “sexcombless” chromosome (In(1)sx) on males and females ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 264-269 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Sexcombless ; Foreleg basitarsus ; Genital disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosome which carries the mutationsexcombless (In(1)sx) affects males and females ofD. melanogaster. In the male foreleg basitarsi the number of sexcomb teeth is dramatically reduced from 10 to 0.7 and the number of transverse rows of bristles is increased from 6 to 8. Females homozygous forIn(1)sx show a normal bristle pattern in the foreleg basitarsus. The genital disc derivatives of both male and femaleIn(1)sx flies are strongly affected. While the external genitalia show a duplicated or a reduced bristle pattern, the internal genitalia are mostly absent. However, the sexually dimorphic tergites and sternites of the abdomen remain unaffected. The male-specific effect on the basitarsus and the general effects on the genital disc derivatives are proposed to represent two different phenotypic effects ofIn(1)sx which may derive from mutations at different gene loci in the inverted chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848414
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  • 10
    Electronic Resource
    Electronic Resource
    Correlation between adult transformation and aldehyde oxidase staining pattern in wing discs ofApterous genotypes inDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 285-288 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; homoeosis ; Compartments ; Aldehyde oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The aldehyde oxidase staining pattern in wing discs ofDrosophila melanogaster bearing the genotypesap blt /ap blt andap blt andap blt /ap 73n showns changes from the wild-type pattern. Extensive areas of the presumptive dorsal posterior wing blade, which are normally unstained, have enzyme activity in these mutants. In wings of these genotypes, dorsal posterior structures are replaced by dorsal anterior wing structures. A strong correlation has been found between the frequencies of various staining patterns in the discs and the extent of transformation in the cuticular structures of the wing, which is consistent with the idea that aldehyde oxidase activity can be used as an indicator in the wing disc of this transformation. Unlike the homoeotic mutationengrailed, apterous has not been interpreted as a selector gene yet the work reported here shows thatapterous alleles can cause changes resembling those of theengrailed phenotype both in aldehyde oxidase staining behaviour and in the cuticular transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848418
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  • 11
    Electronic Resource
    Electronic Resource
    Gap junctions are non-randomly distributed inDrosophila wing discs (1982)
    Springer
    Development genes and evolution 191 (1982), S. 335-339 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Wing disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of gap junctions in mature larvalDrosophila melanogaster wing discs was analyzed by means of quantitative electron microscopy. Gap junctions are non-randomly distributed in the proximal-distal disc axis and in the apical-basal cell axis of the epithelium. In the epithelial cells, the surface density, number and length of gap junctions are greatest in the apical cell region and distal disc region. The average gap junction surface density is 0.0572 μm−1 and 2.77% of the lateral cell surface is composed of gap junctions. In the adepithelial cells, the gap junction surface density is 0.0005 μm−1 and 0.06% of the cell surface is composed of gap junctions. No gap junctions were observed between epithelial cells and adepithelial cells. The absolute area of gap junctions was estimated in a proximal-distal strip of cells in the disc and is considerably less in the folded regions of the epithelium compared to the flat notum and wing pouch regions. The results are discussed with respect to pattern formation and growth control in imaginal discs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848494
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  • 12
    Electronic Resource
    Electronic Resource
    Imaginal disc development in a non-pupariating lethal mutant inDrosophila melanogaster (1981)
    Springer
    Development genes and evolution 190 (1981), S. 11-21 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Ecdysteroid ; Lethal mutant ; Morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imaginal disc development in the non-pupariating lethall(1)npr-1, a mutant that maps to an ecdysone early puff site, is studied in situ, in vitro and in transplanted discs. Disc development is slightly abnormal from the middle of the third instar with severe abnormalities appearing after the rise in 20-hydroxyecdysone that triggers metamorphosis. The mutant discs only partly evaginate and do not undergo any of the detailed morphological changes characteristic of metamorphosis. Treatment of the mutant dises in vitro with colcemid and trypsin facilitates evagination but the appendages remain morphologically abnormal. A number of differentiative processes occur in mutant discs in situ and in discs transplanted into wild type hosts in spite of the absence of normal morphogenesis. Implications of the observations for normal disc development are discussed. Possible modes of action of thel(1)npr-1 gene are also discussed in light of the observation that the mutant gene maps to a locus which is thought to have a regulatory function in development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868698
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  • 13
    Electronic Resource
    Electronic Resource
    Isolation and characterization ofgrandchildless-like mutants inDrosophila melanogaster (1981)
    Springer
    Development genes and evolution 190 (1981), S. 1-10 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Grandchildless ; Pole cells ; ts-mutant ; Cytoplasmic determinant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two temperature-sensitive sex-linkedgrandchildless (gs)-like mutations (gs(1)N26 andgs(1)N441) were induced by ethylmethane sulphonate inDrosophila melanogaster. They complemented each other and mapped at two different loci (1−33.8±0.7 forgs(1)N26 and 1−39.6±1.7 forgs(1)N441), which were not identical to those of any of thegs-like mutants reported in earlier work. Homozygous females of the newly isolated mutants produced eggs that were unable to form pole cells and developed into agametic adults. Competence of the embryos to form pole cells was not restored by wild-type sperm in either mutant; that is, the sterility caused by these mutations is controlled by a maternal effect. Fecundity and fertility ofgs(1)N26 females were low, and their male offspring showed a higher mortality than that of female offspring, causing an abnormal sex ratio. The frequency of agametic progeny was 93.1% and 55.8%, when the female parents were reared at 25° C and 18° C, respectively. In eggs produced by thegs(1)N26 females reared at 25° C, the migration of nuclei to the posterior pole was abnormal, and almost no pole cell formation occurred in these egg. Furthermore, half of these eggs failed to cellularize at the posterior pole. When the females were reared at 18° C, almost all of the eggs underwent complete blastoderm formation, and in half of these blastoderm embryos normal pole cells were formed. In the other mutant,gs(1)N441, the fecundity and fertility of the females were normal. The agametic frequency in the progeny was 70.8% and 18.6% when the female parents were reared at 25° C and 18° C, respectively. In the eggs laid by females reared either at 25° C or at 18° C, the migration of nuclei to the periphery and cellularization proceeded normally; nevertheless, in the majority of the embryos no pole cell formation occured at the stage when nuclei penetrated into the periplasm. When the females were reared at 18° C, some of the embryos from these females formed some round blastoderm cells with cytologically recognizable polar granules and nuclear bodies, which are attributes of pole cells. The temperature sensitive period ofgs(1)N441 was estimated to extend from stage 9 to 13 of King's stages of oogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868697
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  • 14
    Electronic Resource
    Electronic Resource
    Isolation and characterization of temperature-sensitivelethal (2) giant larva alleles (1984)
    Springer
    Development genes and evolution 193 (1984), S. 90-97 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Temperature-sensitive ; Neoplasms ; Differentiation ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary EMS induced temperature-sensitivelethal (2) giant larva, 1(2)gl, alleles were isolated by screening against a knownl(2)gl allele. Analysis of the lethal phase of thel(2)gl ts-deficiency heterozygotes demonstrated: (1) the majority of thel(2)gl tslarvae survive to late third instar, (2) at 29°C the majority of thel(2)gl tslarvae failed to pupate and only rarely did they differentiate adult cuticular structures, (3) at 15°C the majority of the larvae pupated and frequently differentiated adult cuticular structures. Examination of the imaginal discs ofl(2)gl tslarvae reared at 29°C revealed the presence of morphologically abnormal wing, haltere and leg imaginal discs. No morphologically abnormal discs were found in thel(2)gl tslarvae reared at 15°C. Studies on both the histology and the developmental capacity of the morphologically normal and abnormall(2)gl tsdiscs were performed. The morphologically normal discs are histologically normal and produce a full complement of adult cuticular structures. However, the morphologically abnormal discs contained both regions that maintained the normal monolayer epithelium and regions that had lost the normal tissue architecture. The implants obtained when the morphologically abnormal discs are injected into metamorphosing larvae contained only a limited number of the normal complement of adult structures and usually only structures found in the ventral wing hinge region were recovered. In addition, the “metamorphosed” morphologically abnormal discs contained undifferentiated tissue that gave rise to transplantable neoplasms when cultured in adults. The results of the studies on the pathology of thel(2)gl tslarvae are discussed with respect to the role of thel(2)gl tsfunction during normal development, the autonomy of the neoplastic development of thel(2)gl tstissues, and similarities between neoplastic development inDrosophila and mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848636
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  • 15
    Electronic Resource
    Electronic Resource
    The role of the peripodial membrane of leg and wing imaginal discs ofDrosophila melanogaster during evagination and differentiation in vitro (1984)
    Springer
    Development genes and evolution 193 (1984), S. 180-186 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The thin region of the peripodial membrane is confined to the area overlying the distal anlagen in thoracic discs. During the early stages of evagination the peripodial membrane is greatly stretched, but does not rupture. The appendage then evaginates through the stalk, probably by means of a contraction of the peripodial membrane. The cells of the peripodial membrane of leg and wing discs persist and differentiate sheets of trichomes characteristic of the ventral and lateral thorax. This is discussed in relation to imaginal disc fate maps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848893
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  • 16
    Electronic Resource
    Electronic Resource
    Early neurogenesis in wild-typeDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 308-325 
    Details
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Pattern of neuroblasts ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper deals with morphological aspects of early neurogenesis inDrosophila, in particular with the segregation of neuroblasts from the neurogenic region of the ectoderm and the pattern formed by those wells within both the germ band and the procephalic lobe. The neurogenic ectoderm was found to contain neural precursors intermingled with epidermal precursors, extending from the midline up to the primordia of the tracheal tree along the germ band and laterodorsally in the procephalic lobe. Germ band neuroblasts segregate from the neurogenic ectoderm during a period of several hours according to characteristic spatial and temporal patterns. During the first half of the segregation process the pattern of germ band neuroblasts was found to be the same in different animals in both spatial arrangement and number of cells; this permitted the identification of individual neuroblasts from different embryos. Later in development several difficulties were encountered which precluded an exact description of the neuroblast pattern. The constitution of the neurogenic region is discussed in relation to the phenotype of mutants affecting neurogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848159
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  • 17
    Electronic Resource
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    The role of the peripodial membrane in the morphogenesis of the eye-antennal disc ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 164-170 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The early morphogenesis of the eye-antennal disc ofDrosophila in response to 20-hydroxy ecdysone involves the curling of the eye anlagen dorsally over the antenna. During this process, the area of the peripodial membrane is substantially reduced. The peripodial membrane is taut at this stage, and if it is cut the curling of the disc cannot continue, and the eye anlagen returns to its original position within one minute of the operation. In contrast, cutting the columnar epithelium between the eye and antennal anlagen does not disrupt curling, but actually facilitates it. During curling, the cells of the peripodial membrane appear healthy, and exhibit basal extensions. We suggest that the curling of the eye is mediated by the conversion of cuboidal peripodial membrane cells into pseudostratified columnar epithelium at the edges of the peripodial membrane. Subsequently, cells of the peripodial membrane secrete first a pupal cuticle, and then an imaginal cuticle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848686
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  • 18
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    Electronic Resource
    The evagination of the genital imaginal discs ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 280-284 
    Details
    ISSN: 1432-041X
    Keywords: Evagination ; Morphogenesis ; Metamorphosis ; Intersexual genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Morphogenetic movements of the intersexual genital disc of thedoublesex-dominant mutant ofDrosophila melanogaster were followed during metamorphosis. Intersexual genital discs contain well developed genital primordia of both sexes as well as an anal primordium, and all of these primordia evaginate simultaneously. The female genital primordium is deflected to the ventral side by the male genital primordium which is located anterior to it. Subsequently the anterior parts of the two genital primordia project their internal appendages in parallel in the anterior direction. The morphogenetic movements closely resemble those of the corresponding parts of normal males and females. The disc opens at the stalk along the posterior edge and the two genital primordia completely evert their posterior parts. These areas undergo complex rearrangements whereby the anlage for the male genital arch as well as that for the 8th tergite evert and move around the lateral side of the disc. They both fuse dorsally after enclosing the anal tube. The formation of the characteristic abnormalities of the intersexual genitalia seems not to result simply from spatial problems of the simultaneous evagination of the genital anlagen but rather to be a direct result of the ambiguous genetic signalling in the intersexual cells of these primordia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848661
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  • 19
    Electronic Resource
    Electronic Resource
    Cell degeneration and elimination in the imaginal wing disc, caused by the mutationsvestigial andUltravestigial ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 285-294 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Cell degeneration ; Imaginal disc ; Basal lamina ; Blood cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationsvestigial (vg; recessive) andUltravestigial (vg U; dominant) ofDrosophila melanogaster give rise to identical mutant adult phenotypes in which much of the cases this results from cell death in the presumptive wing margin of the wing disc in the third larval instar, but the process of cell degeneration is quite different in the two mutants. Invg cell death occurs continuously throughout the third larval instar, while invg U it occurs only in the early third instar. Cells fragment and some of the fragments condense, becoming electron dense (“apoptosis”). Both condensed and ultrastructurally normal cell fragments are extruded to the basal side of thevg disc epithelium. They accumulate under the basal lamina in the wing pouch area until they are phagocytosed by blood cells entering the wing pouch during the six hours following pupariation. Fragments are not extruded from thevg U epithelium but are apparently phagocytosed by neighboring epithelial cells. The basal lamina undergoes mophological changes following pupariation and is phagocytosed by blood cells in both wild-type andvestigial, but investigial the degenerated cell fragments are also engulfed by the same blood cells.
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    URL: http://dx.doi.org/10.1007/BF00848662
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  • 20
    Electronic Resource
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    The effect of 5-azacytidine and cytidine analogs onDrosophila melanogaster cells in culture (1983)
    Springer
    Development genes and evolution 192 (1983), S. 299-302 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Teratogens ; Drosophila ; 5-Azacytidine ; Methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of cytidine and cytidine analogs were studied inDrosophila embryonic cell cultures and two wild-type established cell lines, Oregon-R and Schneider line 2. Primary embryonic cultures have been shown to be an excellent system for the study of embryonic development; a number of cell types undergo normal differentiation in vitro. Treatment of these cultures with putative teratogens resulted in an inhibition of muscle and/or neuron differentiation in our study. Treatment of these cells with cytidine and seven other analogs had no effect on neuron and muscle differentiation. The compound 5-azacytidine, when added to primary cell cultures, inhibited normal differentiation at subtoxic doses while inducing the production of three proteins that comigrate with the heat-shock proteins, hsp 23, 22a and 22b. 5-Azacytidine did not stimulate differentiation in Oregon-R or SchneiderDrosophila cell lines. The in vitro blockage of differentiation by 5-azacytidine suggests that it may act as a teratogen.
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    The effect of temperature onshibire ts cell clones in the compound eye ofDrosophila melanogaster (1980)
    Springer
    Development genes and evolution 188 (1980), S. 55-63 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Compound eye ; shibire ts ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analysed the effect of temperature on both developing and adult eye cell clones homozygous forshi ST139, a temperature-sensitive mutant ofDrosophila melanogaster. The mutant gene, autonomous in its cellular expression, causes structural modifications of ommatidial cells when adult clones of cells are exposed to the restrictive temperature (29°C) for several days. However, the mutant phenotype reverses to normal within 4 days at the permissive temperature (20°C). The results of pulse, shift-up and shift-down experiments show that the temperaturesensitive period for developing compound eye cells is from the late second instar up to the early pupa. Cytodifferentiation of compound eye cells is blocked by restrictive temperature treatment during this period, whereas cell proliferation does not seem to be directly affected. These results are discussed with regard to the other known aspects of the phenotype observed in mutant individuals.
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    The spatial arrangement of germ line cells in ovarian follicles of the mutantdicephalic inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 388-393 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
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    Cell interactions during the fusionin vitro ofDrosophila eye-antennal imaginal discs (1984)
    Springer
    Development genes and evolution 193 (1984), S. 406-413 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fusion of the eye-antennal discs during culturein vitro has been investigated, and the complex morphogenetic movements which occur during the formation of the head capsule of the insect are described. The initial contact between the eye anlagen is by means of cell processes spanning the gap between the two discs. Subsequently the two epithelia become firmly apposed, and then the integrity of the epithelium in the region of fusion breaks down, cells appearing to move to new positions in order to form an epithelium which unites the two discs. The epithelium eventually secretes a pattern of cuticular structures which is continuous between the derivatives of the two discs. Bristles on either side of the line of fusion are perfectly aligned, and structures such as the median ocellus, which are formed jointly by the cells of the two discs, differentiate normally. This is also found when left and right eye-antennal discs of different genotypes are placed side-by-side, indicating that processes of pattern regulation can occur in culture.
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    Normal and lectin-mediated aggregation in aDrosophila cell line (1981)
    Springer
    Development genes and evolution 190 (1981), S. 118-122 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Aggregation ; Lectins ; Cell surface ; Embryo-derived cell line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper we describe the aggregation of cells from embryo-derived cell lines ofDrosophila, measured by examining the ability of single cells to adhere to one another when suspended in culture medium and swirled on a rotary shaker. Using this method we demonstrated the presence of receptors for Concanavalin A, soybean agglutinin, and possibly wheat germ agglutinin on the surface of Schneider's line-2 cells. Our work provides basic descriptive and background information for further studies onDrosophila cells, including those isolated from imaginal discs.
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    A maternal effect mutation leading to deficiencies of organs and homeotic transformations in the adults ofDrosophila (1981)
    Springer
    Development genes and evolution 190 (1981), S. 132-138 
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    ISSN: 1432-041X
    Keywords: Maternal effect mutant ; Homeotic-mutants ; Pattern formation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The temperature sensitive mutationfs(l)h is characterized at the restrictive temperature of 29°C by both a maternal effect responsible for the early embryonic lethality and pupal zygotic lethality. The two phenotypes are inseparable and map at a short deletion in the X chromosome (7Dl, 7D5-6). At semipermissive temperatures, hemizygous mutant females produce adults with morphological defects, such as organ deficiencies and homeotic transformations of haltere to wing and third leg to second leg. These defects depend on the maternal genotype and are governed by an early temperature sensitive period, which covers the end of oogenesis and the first hours of embryogenesis. Furthermore, this maternal effect mutation interacts with some dominant mutations of the bithorax system. These properties suggest thatfs(l)h is somehow involved in segmental determination.
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    Sequential gene activation by ecdysteroids in polytene chromosomes ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 103-111 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Polytene Chromosomes ; Ecdysteroids ; Fat Body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in polytene chromosome 3 L puffing patterns in the fat body ofDrosophila melanogaster larvae and prepupae are compared to those in the salivary gland. While some general features are common to the two tissues, there are differences which reflect their different developmental roles. In vitro experiments with fat body chromosomes show that they have a distinct response to ecdysteroids which is different from that of salivary gland chromosomes, and which does not,in this culture system, reproduce the changes observed in normal development. In short term culture experiments, the fat body chromosomes appear more sensitive to ecdysteroids than the salivary gland chromosomes and, although 20-OH ecdysone is more active than ecdysone in these assays, the possibility is not excluded that ecdysone has a role in normal development as it appears to alter gene activity at physiological levels in these cells.
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    The morphological response of Kc-H cells to ecdysteroids: Hormonal specificity (1980)
    Springer
    Development genes and evolution 189 (1980), S. 1-15 
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    ISSN: 1432-041X
    Keywords: Cell line ; Drosophila ; Ecdysone ; Ecdysterone ; Hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of the line Kc, derived fromDrosophila melanogaster embryos, extend long processes when exposed to ecdysteroid hormones. We have devised a quantitative assay for this morphological response, using the subline Kc-H. The assay was used to characterize the conditions required for the response. A halfmaximal response is elicited by approximately 10−8M 20-hydroxyecdysone; the response is saturated by 10−7M 20-hydroxyecdysone, which causes detectable elongation within a few hours, and a maximal response after 2–3 days. The response occurs substantially normally in the absence of serum, during growth in suspension, and in over-crowded cultures. It is not elicited by cyclic nucleotides, vertebrate growth factors, or a variety of other non-ecdysteroid reagents. Of 60 ecdysteroid compounds tested, only those which were active in other insect test systems elicited the response, and the concentrations required were approximately proportional to the concentrations active in other in vitro systems. We conclude that the response of Kc cells to 20-hydroxyecdysone retains basic features of the ecdysteroid response of intact tissues and therefore that Kc cells are a useful model system for studying ecdysteroid action.
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    Developmental studies on two ecdysone deficient mutants ofDrosophila melanogaster (1980)
    Springer
    Development genes and evolution 189 (1980), S. 57-67 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Ecdysone deficient mutants ; Ecdysteroid titer ; Ring gland ; Fine structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper describes two ecdysone-deficient, recessive-lethal mutants,lethal(1)giant ring gland (grg) andlethal(1)suppressor of forked mad-ts (mad-ts: Jürgens and Gateff 1979) and compares their ecdysteroid titers with that of the wild-type. Mutant larvae show a much reduced ecdysteroid content, amounting to 1/10 to 1/30 of the wild-type values, but never a true titer peak. They fail to pupate and die after 1–3 weeks. Ecdysteroid feeding elicits different responses in the larvae of the two mutants.mad-ts larvae pupate within 24 h, thus showing that their low ecdysteroid titer is directly connected to their inability to pupate.mad-ts resembles the mutantlethal (3)ecdysone-1 ts (Garen et al. 1977). Thegrg mutant larvae, on the other hand, fail to pupate after 20-hydroxyecdysone feeding as well as injection. The primary defect of thegrg mutant is not entirely clear. Thegrg larval salivary gland cells appear to possess normal ecdysteroid receptors. Furthermore, the low ecdysteroid titer ingrg is not the result of an increased ecdysteroid catabolism. The primary defect in the mutant may lie in the malfunctioning neurosecretory cells which do not show neurosecretion in histological preparations. Further support for this notion comes from electronmicrographs of the enlargedgrg ring glands which, in contrast to the wild-type, do not possess nerve endings. In the wild-type three ecdysteroid peaks were found: one shortly before puparium formation, the second at approximately 12 h and the third at about 30 h after pupation. The ecdysteroid titer peak in late third instar, wild-type larvae is mainly due to the presence of 20-dydroxyecdysone as shown by radioimmunoassays after thin layer chromatography and derivatization followed by gas liquid chromatography and mass spectroscopy. In addition, a number of unidentified polar and apolar metabolites were also present.
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    A clonal analysis of cell lineage and growth in the male and female genital disc ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 42-55 
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    ISSN: 1432-041X
    Keywords: Clonal analysis ; Growth ; Cell lineage ; Genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InDrosophila, the terminalia (i.e. internal and external analia and genitalia, except the gonads) are formed by the genital disc. Comparative studies suggested that this disc may have evolved through fusion of the imaginal primordia of the last 3 or 4 abdominal segments. The present report describes the clonal relationships within the complex genital disc. Genetically marked cell clones were induced in male and female embryos and larvae heterozygous for cell marker mutations. 1) Frequencies and sizes of clones suggest that the embryonic disc anlage consists of 14–17 precursor cells: 4–6 for the analia, some 7 for the male genitalia, and 3–4 for the female genitalia. These cells grow exponentially during larval development. 2) In both sexes, the clones were confined to either analia or genitalia, suggesting two separate cell lineages already established at blastoderm. 3) Internal and external genitalia remain in the same compartment at least up to 60 h (end of first instar). 4) A clonal restriction appeared around 84 h (mid second instar), separating a dorsal from a ventral part in the male genitalia. The ventral compartment comprises the ventral part of the lateral plate and clasper, hypandrium, and all internal genitalia. No such boundary was detected in the female. 5) In the female, analia and parovaria originate from the same precursors; another cell lineage forms eighth tergites, vaginal plates, oviduct, receptacle, and spermathecae. 6) In female analia, dorsal and ventral plate share common precursors at least up to 84 h. A medio-lateral boundary may appear at 84 h in the ventral anal plate. No clonal restriction was found in the male analia. 7) At all times, clones could cross between left and right sides of the symmetrical terminalia; they consistently did so via ventral structures. 8) The results are discussed in a phylogenetic context, and we propose that the clonal relations reflect the evolution of the complex genital disc.
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    Timing and heritability of theNasobemia transformation inDrosophila (1980)
    Springer
    Development genes and evolution 189 (1980), S. 147-153 
    Details
    ISSN: 1432-041X
    Keywords: Homeotic mutant ; Drosophila ; Clonal analysis ; Timing of gene action ; Determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nasobemia (Ns) is a dominant homeotic mutant ofDrosophila melanogaster which converts parts or all of the antenna to mesothoracic leg.Ns has a temperature sensitive period between 48 and 60 h. The hypothesis thatNs acts during this period and is not required thereafter to maintain the homeotic transformation to leg was tested by removingNs fromNs/+ cells at different stages of development through X-ray induced somatic recombination. The expression of theNs homeotic transformation in recombinant wild type (+/+) cells increased sharply between 48 and 65 h. In clones induced after 65 h the expression of the leg transformation was equal in large and small +/+ clones. We interpret these results as supporting the hypothesis that transient action ofNs between 48 and 65 h switches antennal cells to a clonally stable leg determined state whose maintenance does not require futherNs action.
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    Maternal effects of zygotic mutants affecting early neurogenesis inDrosophila (1982)
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    Development genes and evolution 191 (1982), S. 191-201 
    Details
    ISSN: 1432-041X
    Keywords: Neurogenic mutants ; Maternal effects ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The size of the neurogenic region ofDrosophila melanogaster is under the control of several genes of zygotic expression. Lack of function from any of those genes produces an increase of the size of the neurogenic region at the expense of the epidermal anlage. However, differences exist in the extent of neuralisation achieved by each of the genetic loci upon mutation. The present results show that in the case ofN andmam phenotype differences are due to different contributions of maternal gene expression. This could be shown by studying the phenotype which appeared in mutant embryos when the oocytes developed from homozygous mutant precursor cells. Clones of mutant cells were induced in the germ line of females heterozygous for the neurogenic mutationin trans over germ line dependent, dominant female sterile mutations. After removing maternal information the phenotype ofN andmam mutants became identical in both cases. Furthermore maternal information fromN + was found to be necessary for viability of the wildtype.
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    Cell lineage restrictions in the genital disc ofDrosophila revealed byMinute gynandromorphs (1983)
    Springer
    Development genes and evolution 192 (1983), S. 337-346 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Gynandromorphs ; Genital disc ; Compartments ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genital imaginal disc ofDrosophila differentiates the terminalia, i.e. the genitalia and analia, of both sexes. It represents a composite anlage, containing a female genital primordium, a male genital primordium and an anal primordium. In normal males and females, only one of the two genital primordia differentiates; the other is developmentally repressed. Therefore, cell-lineage relationships between the male and female genital primordia can only be studied in sexual mosaics which differentiate female and male cells. We producedMinute (M)‖non-Minute(M+) gynandromorphs and selected those with sexually mosaic terminalia for a cell-lineage analysis. In these mosaics, either the male (XO) or female (XX) cells wereM + and thus had a growth advantage. The differential growth rates served as a tool to detect clonal restrictions. In control gynandromorphs (M +‖M +), the amount of female genitalia differentiated was largely independent of the amount of male genitalia present. In contrast, male and female anal structures, as a rule, added up to one full set. The same was true for the experimentalM‖M + gynandromorphs, but the contribution ofXX andXO cells to mosaic terminalia changed drastically due toM + cells competing successfully against the more slowly growingM cells. Specific subsamples ofM‖M + gynandromorphs showed thatM cells in a non-mosaic primordium are shielded from cell competition taking place in the neighbouring mosaic primordium. We conclude that the three primordia of the genital disc represent developmental compartments. In the genital primordia, even developmentally repressedM + cells compete successfully against developmentally activeM cells.
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    Isolation and characterization of temperature-sensitivelethal(2)giant larva alleles (1984)
    Springer
    Development genes and evolution 193 (1984), S. 98-107 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Neoplasms ; Promotion ; Regeneration ; Temperature-sensitive ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper we present an analysis of the behavior ofl(2)gl tsimaginal wing discs during culture in adult hosts. Thel(2)gl tslarvae reared at 29° C contain two types of wing discs, those that are morphologically normal and those that are abnormal. When discs of both types are cultured in adult hosts at 29° C, the restrictive temperature, they give rise to transplantable neoplastic tissue. However, when the 29° C reared discs are cultured at 15° C, the permissive temperature, the morphologically normal discs maintain their morphology, but the morphologically abnormal discs give rise to neoplasms. Thel(2)gl tslarvae reared at 15° C contain only morphologically normal discs. When these discs are cultured in adult hosts at 29° C they give rise to neoplasms, however if the discs are cultured at 15° C they maintain their normal morphology. These results demonstrate: (1) that all wing imaginal discs obtained from 29° C rearedl(2)gl tslarvae are competent to undergo neoplastic development, (2) the morphologically abnormal discs obtained from the 29° C rearedl(2)gl tslarvae are committed to neoplastic development, (3) the neoplastic development of the morphologically normal discs is temperature dependent, (4) once the neoplastic development of thel(2)gl tsdiscs has been initiated the process is not readily reversible. In addition, the ability ofl(2)gl tswing discs to perform epimorphic regulation was tested by amputating morphologically normal permissively rearedl(2)gl tswing discs and culturing both fragiments at the permissive temperature. Fragments of control wild-type discs maintained their morphology during culture at the permissive temperature. However, both fragments of txel(2)gl tsdiscs became neoplastic. This result is discussed with respect to a possible role for thel(2)gl +function in epimorphic regulation and with respect to the phenomena of tumor promotion in vertebrates.
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    Changes in the distribution of gap junctions inDrosophila melanogaster wing discs during the third larval and early pupal stages of development (1984)
    Springer
    Development genes and evolution 193 (1984), S. 187-196 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Imaginal disc ; Pattern formation ; EM Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Developmental changes in the distribution of gap junctions in early, mid and late third larval stage wing discs and in pupariation+6 h and pupariation+24 h stage wing discs fromDrosophila melanogaster were analyzed by quantitative electron microscopy. Gap junctions occur in all 12 intradisc regions examined in each of the five developmental stages. Their distribution is non-random and changes during development which suggests that they are developmentally regulated. The gap junctions are not static structures, rather they grow and regress during development. The changes tend to be gradual ones without sudden increases or decreases. Gap junctions continuously form and grow in size throughout the third larval stage and during the first 6 h following pupariation. Their surface density, number, percent of the lateral plasma membrane area, and absolute area as well as the lateral plasma membrane surface density all increase during this time. Between pupariation+ 6 h and pupariation+24 h all but one of these parameters decrease indicative of gap junctional breakdown. Gap junctions are most numerous and change least during development in the apical cell regions where intercellular contacts are close and stable. They change most in the basal cell regions where intercellular contacts tend to be looser and change during development. The most dramatic change is in the absolute area which increases by a factor of 23 between the early third larval stage and pupariation+24 h. At pupariation the rate of gap junction growth undergoes a transient increase before the phase of disassembly begins. Developmental changes in gap junction surface density are closely coupled with changes in the lateral plasma membrane surface density which suggests that these may be coregulated. Evidence from mutants suggests that when the number and density of gap junctions fail to increase in proportion to lateral plasma membrane growth, wing disc development will be abnormal. Our results support the idea that some minimum gap junction density is required for normal development and that this must increase as development proceeds. The results are consistent with the notion that gap junctions are involved in pattern formation and growth control and are discussed with respect to the acquisition of competence for metamorphosis, disc growth, disc morphogenesis and changes in the hormonal environment.
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    Transdetermination in leg imaginal discs ofDrosophila melanogaster undDrosophila nigromelanica (1981)
    Springer
    Development genes and evolution 190 (1981), S. 156-160 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Transdetermination ; Homeosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transdetermination capacities of leg discs ofDrosophila melanogaster were examined by mechanically disrupting and kneading whole discs from late third instar larvae and by culturing the resulting tissue mass for 10–14 days in adult female abdomens where the cells continued to divide. The grown implants were then dissected from the abdomens and injected into third instar larvae to undergo metamorphosis. After this treatment, prothoracic leg discs ofDrosophila melanogaster transdetermined with a high frequency (59% of all implants) to wing. Mesothoracic leg discs also transdetermined to wing, but at a very low frequency (4%). Metathoracic leg discs exhibited the same low frequency of transdetermination (4%), but in this case the direction of transdetermination was to haltere (Table 1,D. melanogaster). Very similar results were obtained with leg discs ofDrosophila nigromelanica (Table 1,D. nigromelanica), showing that the peculiar behavior of the three leg discs is not unique forDrosophila melanogaster. The homeotic mutation Polycomb (Pc 3) which partially transforms meso- and metathoracic legs into prothoracic legs did not significantly increase the frequencies of transdetermination in these leg dises and had clearly no effect on the direction of transdetermination (Table 1).
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    Wound healing and regeneration in the imaginal wing disc ofDrosophila (1981)
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    Development genes and evolution 190 (1981), S. 185-190 
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    ISSN: 1432-041X
    Keywords: Wound healing ; Regeneration ; Imaginal discs ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When complementary fragments of an imaginal disc ofDrosophila are cultured for several days prior to metamorphosis, usually one fragment will regenerate while the other will duplicate. It has been proposed that wound healing plays an important part in disc regulation (French et al. 1976; Reinhardt et al. 1977) by initiating cell proliferation and determining the mode of regulation. We tried to delay the wound healing process by leaving a region of dead cells between the wound edges. In “06” fragments (Bryant 1975a) wound healing has occurred after 1–2 days of culture and the regeneration of missing structures after 2–4 days of culture. We observed that leaving a region of dead cells between the wound edges delays both wound healing and the regeneration of missing structures by 2 days. When disc fragments are cultured in female abdomens and then exposed to3H-thymidine to label replicating cells, then the label is found to be localised around the wound. We observed that delaying wound healing does not delay this localisation of labelled nuclei indicating that wound healing may not be required to initiate DNA replication.
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    Growth is required for cell competition in the imaginal discs ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 289-291 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Cell competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imaginal wing discs from late third-instar larvae were gammairradiated to induce clones of rapidly growingMinute − cells in a background of slowly growingMinute cells and culturedin vivo for periods up to 18 days. Clones in discs cultured for 16 to 18 days did not grow significantly larger than clones in uncultured controls, indicating that competition between populations of cells having potentially different mitotic rates does not occur in imaginal discs after their growth is completed.
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    Homologies of positional information in thoracic imaginal discs ofDrosophila melanogaster (1982)
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    Development genes and evolution 191 (1982), S. 293-300 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Positional information ; Homology ; Intercalary regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The regulative behavior of fragments of the imaginal discs of the wing and first leg was studied when these fragments were combined with fragments of other thoracic imaginal discs. A fragment of the wing disc which does not normally regenerate when cultured could be stimulated to regenerate by combination with certain fragments of the haltere disc. When combined with a haltere disc fragment thought to be homologous by the criteria of morphology and the pattern of homoeotic transformation, such stimulated intercalary regeneration was not observed. Combinations of first and second leg disc fragments showed that a lateral first leg fragment could be stimulated to regenerate medial structures when combined with a medial second leg disc fragment but not when combined with a lateral second leg disc fragment. Combinations of wing and second leg disc fragments showed that one fragment of the second leg disc is capable of stimulating regeneration from a wing disc fragment while another second leg disc fragment fails to stimulate such regeneration. It is suggested that absence of intercalary regeneration in combinations of fragments of different thoracic imaginal discs is a result of homology or identity of the positional information residing in the cells of the fragments. The pattern of correspondence of positional information revealed by this analysis is consistant with the pattern of homology determined by morphological observation and by analysis of the positional specificity of homoeotic transformation among serially homologous appendages. The implications of the existence of homologous positional information in wing and second leg discs which share a common cell lineage early in development are discussed.
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    Expression of the zygotic genome in blastoderm stage embryos ofDrosophila: Analysis of a specific protein (1980)
    Springer
    Development genes and evolution 188 (1980), S. 153-156 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Embryogenesis ; mat (3) 1 mutation ; Two-dimensional gels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The synthesis of a protein which has been detected in blastoderm cells but not in pole cells (Gutzeit and Gehring 1979) has been studied further by means of two-dimensional gel electrophoresis. This protein could not be detected at the nuclear multiplication stage. The protein is translated from mRNA which is transcribed at the blastoderm stage since it is not synthesized in detectable amounts when embryos are injected with α-amanitin prior to the blastoderm stage. Also the protein could not be detected when RNA from freshly laid eggs was translated in vitro. Embryos from females which are homozygous for the mutationmat (3) 1 form pole cells but no blastoderm cells (Rice and Garen 1975). Thesemat (3) 1 embryos, as we will call them in this report, express the protein if aged for a period of time sufficient for completion of blastoderm cell formation in control wild-type embryos.mat (3) 1 embryos and embryos injected with α-amanitin show the same syndrome of visible developmental anomalies; however, the studied protein could only be detected inmat (3) 1 embryos but not in α-amanitin injected embryos.
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    Compartments and distal outgrowth in theDrosophila imaginal wing disc (1980)
    Springer
    Development genes and evolution 188 (1980), S. 157-161 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Compartments ; Distal outgrowth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Peripheral tissue of the imaginal wing disc gives rise to the proximal mesothoracic structures of the adult. Pieces of peripheral tissue, which have no regenerative capacity when cultured as intact fragments, are capable of distal outgrowth (regeneration) after dissociation and reaggregation. This ability depends on the region of the disc periphery from which the fragment is taken. Extensive distal outgrowth occurs in reaggreages of a fragment containing equal proportions of tissue from anterior and posterior developmental compartments. The extent of outgrowth decreases as the proportion of posterior tissue is reduced, so that a fragment containing only anterior tissue shows no regeneration after dissociation. Limited distal outgrowth occurs in reaggregates of a wholly posterior fragment, but the regenerative capacity is increased greatly when a small amount of anterior tissue is included. It is concluded that distal outgrowth in the wing disc requires an interaction between cells of the anterior and posterior compartments.
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    Morphogenesis in the embryo ofDrosophila melanogaster — Germ band extension (1980)
    Springer
    Development genes and evolution 188 (1980), S. 163-177 
    Details
    ISSN: 1432-041X
    Keywords: Yolk sac ; Ultrastructure ; Embryogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes at the ultrastructural level during germ band extension in the embryo ofDrosophila melanogaster are described. Cytoplasmic connections between cells and the yolk sac are present during initial cellular movements. At this time, a continuous system of microfilaments is present adjacent to the membranes in the connections and at the periphery of the yolk sac. As germ band extension progresses, this system becomes discontinuous, and microfilaments are apparent only in the immediate vicinity of the connections. Cytoplasmic connections are disassembled at approximately the midpoint of extension; at the same time, extensive membrane associations develop between germ band cells and between these cells and adjacent yolk sac membranes. Positioning and orientation of cytoplasmic connections suggest that the yolk sac, via these connections, is actively involved in the cellular movements of early germ band extension.
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    Embryogenesis inDrosophila: Can a single mechanism explain the developmental segregation of germ-line and somatic cells and their subsequent determination? (1980)
    Springer
    Development genes and evolution 188 (1980), S. 179-185 
    Details
    ISSN: 1432-041X
    Keywords: Determination ; Germ-line ; Somatic cells ; Inhibitor gradient hypothesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A hypothesis is presented which explains the segregation of germ cells from somatic cells, and the subsequent determination of both cell types with a single mechanism. This hypothesis is in part based on that of Meinhardt (1977) and can be summarized as follows: In the newly fertilized egg, the action of a sink in the pole plasm leads to the formation of an anterior-posterior gradient of an inhibitor. The concentration of this inhibitor in the posterior 20% of the egg is below that needed to repress synthesis of an activator. When, during the nuclear division stage, nuclei enter this posterior region, synthesis of the activator begins. As the activator is autocatalytic, this leads to the formation of a peak of activator in this region; and since the activator also catalyses the synthesis of the inhibitor, a peak of inhibitor is formed in the same place. The inhibitor then diffuses anteriorly through the periplasm, forming a posterior-anterior gradient. The presence of this inhibitor in the periplasm causes the nuclei that enter the periplasm to form blastoderm cells and to take up particular segmental states appropriate to their position, while those that remain in the yolk-containing plasm develop into vitellophages. The action of the sink in the pole plasm is postulated to result in the formation of the pole cells, and subsequently to direct some of these into forming cells of the germ-line.
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    Is regeneration inDrosophila the result of epimorphic regulation? (1980)
    Springer
    Development genes and evolution 189 (1980), S. 91-96 
    Details
    ISSN: 1432-041X
    Keywords: Epimorphic regulation ; Drosophila ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It has been known for many years that when a wing disc ofDrosophila is bisected, and the fragments cultured in adult females, regulation occurs and either a complete disc is regenerated or the fragment is duplicated. We have investigated how this regeneration process occurs. To establish which cells contribute to the regenerate, and thus determine if regeneration is the result of epimorphic regulation, fragments of discs, after culture in an adult for one to five days, were exposed to3H-thymidine to label replicating cells. Imaginal discs, both whole and as regenerating fragments, undergo some DNA replication which is distributed throughout the disc, but cut discs frequently show clusters of labelled cells around the wound, indicating that regeneration is probably epimorphic.
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    Three-dimensional fate map of the female genital disc ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 270-274 
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    ISSN: 1432-041X
    Keywords: Fate map ; Repressed primordium ; Sex determination ; Genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The female genital disc ofDrosophila melanogaster was cut into distinct fragments, and the prospective fates of the fragments were determined by putting them through metamorphosis in host larvae. The dorsal epithelium contains the anlagen for the anal plates and parovaria, as well as the repressed male genital primordium. The ventral epithelium gives rise to all of the female genital structures except for the parovaria. The results were compared with published fate maps and observations made in experiments with sex-transforming mutations. This allowed us to establish a detailed three-dimensional fate map of the female genital disc, which shows a well-developed female genital primordium in the ventral epithelium, a repressed male genital primordium in the anterior part of the dorsal epithelium and an anal primordium in the posterior region of the dorsal disc epithelium.
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    The evagination of the genital imaginal discs ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 275-279 
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    ISSN: 1432-041X
    Keywords: Evagination ; Morphogenesis ; Metamorphosis ; Female genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The morphology of the evaginating female genital disc ofDrosophila melanogaster was examined at different stages of metamorphosis. The observations show that the internal genital organs are derived from the anterior half of the disc and that their morphogenesis is mainly a protrusion of the different primordial areas of the disc epithelium. The external genital and anal derivatives originate from the posterior half of the disc, which undergoes complex rearrangements during metamorphosis. The disc opens along the posterior margin and the dorsal and ventral epithelia evert and thereby completely reverse their anteroposterior orientation. Dramatic elongation has been observed during the formation of the seminal receptacle. The cells of the repressed male genital primordium do not form any recognizable structures and are assumed to be eliminated during metamorphosis.
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    Crosslinking of theDrosophila chorion involves a peroxidase (1980)
    Springer
    Development genes and evolution 189 (1980), S. 187-196 
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    ISSN: 1432-041X
    Keywords: Eggshell ; Chorion ; Peroxidase ; Crosslinking ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary TheDrosophila chorion contains an endogenous peroxidase activity which remains inactive until late stage 14 when it catalyzes the crosslinking of the chorionic proteins. Using explanted follicles developing in vitro, premature, but otherwise normal crosslinking can be induced with hydrogen peroxide and normal crosslinking can be prevented with peroxidase inhibitors. Inhibition or premature activation of the shell peroxidase allows characterization of chorionic filament specific proteins and establishes new criteria for the identification of eggshell components.
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    Topological specificity of phenotype expression of neurogenic mutations inDrosophila (1983)
    Springer
    Development genes and evolution 192 (1983), S. 317-326 
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    ISSN: 1432-041X
    Keywords: Neurogenic mutations ; Topological specificity ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Neurogenic mutations have been found to cause the neuralization of certain regions of the ectoderm and yet to permit normal development of the remaining embryonic cells. Thus, it seems that the activity of the wild-type alleles of these genes is dispensable in a considerable fraction of the embryo during wild-type development. This effect might be a consequence of the cells' position within the embryo; alternatively, it might be independent of the position but be due rather to the genetic activity experienced by the cells previous to their commitment. The results described in this paper indicate that genes controlling patterning along the embryonic dorso-ventral perimeter (dorsal and Toll) are epistatic to genes controlling neurogenesis, their activity deciding which ectodermal cells are susceptible to neurogenesis. Using alleles with low expressivity, evidence was obtained showing that the tracheal placodes define the boundary of the territory which has neurogenic abilities at thoracic and abdominal levels.
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    Clonal analysis ofsex-lethal, a gene needed for female sexual development inDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 211-214 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Clonal analysis ; Sex determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationSxl f , located on the X-chromosome, is a sex-limited recessive lethal that specifically kills 2X; 2A flies while it does not affect X; 2A flies (Cline 1978). We have analyzed the role ofSxl f on sex determination by a clonal analysis of a new spontaneous allele,Sxl fLS . Female embryos and larvae heterozygous forSxl fLS were irradiated at different times of development to generate homozygousSxl fLS clones which were recognized by linked marker mutations. We have studied the phenotype of such clones on sexually dimorphic regions of the fly (foreleg basitarsus, 5th, 6th and 7th tergites, analia and external genitalia). Despite their female (2X; 2A) chromosomal constitution, clones homozygous forSxl fLS differentiated male structures. These results confirm and extend the preliminary report of Cline (1979). They show that the wildtype product ofSxl f is required for female development.
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    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 267-282 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.
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    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 296-307 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to identify X-chromosomal genes required inDrosophila for early patterning and morphogenesis, we examined embryos hemizygous for EMS-induced lethal mutations to determine which of those mutations cause gross morphological defects. Embryos from 2711 lethal lines, corresponding to 3255 lethal point mutations were studied. Only 21% caused death during embryogenesis and of these, only one-sixth, or 3% of the total lethals, were associated with defects visible in the final cuticle pattern. Of the 114 point mutants causing visible cuticle defects, 76 could be assigned to 14 complementation groups. An additional 25 mutations mapping to regions of the X-chromosome not covered by male fertile duplications were assigned to six complementation groups based on similarities of map position and phenotype. Thirteen mutations could not be assigned to complementation groups. All mutations allowed normal development through the cellular blastoderm stage, the first defects associated with the earliest acting loci being observed shortly after the onset of gastrulation. The phenotypes of the various loci range from alterations in segment pattern or early morphogenetic movements to defects in final pigmentation and denticle morphology. Cuticle preparations were also examined for 63 deletions spanning in total 74% of the X-chromosome, as well as for 8 deletions and point mutations derived in saturation mutagenesis screens of the fourth chromosome (Hochman 1976). With the exception of defects in head morphology and defects in cuticle differentiation, none of the hemizygous deletions showed phenotypes other than those predicted by point mutations known to lie in those regions. No deletion caused new or unknown alterations in gastrulation, segmentation or cuticle pattern.These results suggest that the number of genes required zygotically for normal embryonic patterning is small and that most, if not all such loci, are represented by point mutations in our collection.
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    TheUbx syndrome ofDrosophila: the prothoracic transformation (ppx) is independent ofbx, bxd andpbx (1984)
    Springer
    Development genes and evolution 193 (1984), S. 263-265 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Biothorax complex ; Prothoracic transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If, early in development, theUbx + gene is removed by mitotic recombination from cells of the meso-and metathoracic leg primordia, theseUbx − cells develop as in the posterior prothoracic leg. We show that this transformation, termedpostprothorax, is a discrete genetic function that is independent of other homeotic transformations such asbx, pbx orbxd, which also result from the inactivation of theUbx gene.
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    Mutations affecting the pattern of the larval cuticle inDrosophila melanogaster (1984)
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    Development genes and evolution 193 (1984), S. 283-295 
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    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The present report describes the recovery and genetic characterization of mutant alleles at zygotic loci on the third chromosome ofDrosophila melanogaster which alter the morphology of the larval cuticle. We derived 12600 single lines from ethyl methane sulfonate (EMS)-treatedst e orrucuca chromosomes and assayed them for embryonic lethal mutations by estimating hatch rates of egg collections. About 7100 of these lines yielded at least a quarter of unhatched eggs and were then scored for embryonic phenotypes. Through microscopic examination of unhatched eggs 1772 lines corresponding to 24% of all lethal hits were classified as embryonic lethal. In 198 lines (2.7% of all lethal hits), mutant embryos showed distinct abnormalities of the larval cuticle. These embryonic visible mutants define 45 loci by complementation analysis. For 32 loci, more than one mutant allele was recovered, with an average of 5.8 alleles per locus. Complementation of all other mutants was shown by 13 mutants. The genes were localized on the genetic map by recombination analysis, as well as cytologically by complementation analysis with deficiencies. They appear to be randomly distributed along the chromosome. Allele frequencies and comparisons with deficiency phenotypes indicate that the 45 loci represent most, if not all, zygotic loci on the third chromosome, where lack of function recognizably affects the morphology of the larval cuticle.
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    Heterospecific combinations of germ cells and gonadal soma betweenDrosophila melanogaster, D. mauritiana andD. ananassae (1984)
    Springer
    Development genes and evolution 194 (1984), S. 99-106 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Pole cell transplantation ; Heterospecific combinations ; Gametogenesis ; Chorion morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We transplanted pole cells betweenDrosophila melanogaster, D. mauritiana andD. ananassae to investigate the ability of germ cells to develop in the gonad of a heterospecific host, and to study the interaction between somatic follicle cells and the cells of the germ line in producing the species-specific chorion. FemaleD. mauritiana germ cells in aD. melanogaster ovary produced functional eggs with normal development potential. The same is true for the reciprocal combination. FemaleD. ananassae pole cells in aD. melanogaster host only developed to a very early stage and degenerated afterwards. None of the interspecific combinations of male pole cells led to functional sperm. We could not determine at what stage the transplanted male pole cells were arrested. The cooperation of follicle cells and the oocyte-nurse cell complex in producing the chorion was studied using the germ-line-dependent mutationfs(1) K10 ofD. melanogaster, which causes fused respiratory appendages and an abnormal chorion morphology. Wild-type femaleD. mauritiana germ cells in a mutantfs(1) K10 D. melanogaster ovary led to the production of wild-type eggs withD. melanogaster-specific, short respiratory appendages. On the other hand,D. melanogaster fs(1) K10 germ cells in aD. mauritiana ovary induced the formation of eggs with mutant fused appendages which were, however, typicallyD. mauritiana in length. When.D. mauritiana pole cells developed in aD. melanogaster ovary, the chorion exhibited a new imprint pattern that differs from both species-specific patterns.
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    Adaptation ofDrosophila enzymes to temperature. III. Evolutionary conservatism in mitochondrial enzymes (1980)
    Springer
    Journal of molecular evolution 16 (1980), S. 37-46 
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    ISSN: 1432-1432
    Keywords: Evolution ; Drosophila ; Temperature ; Mitochondrial enzymes ; Kinetic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The evolutionary behavior of two mitochondrial enzymes (L-glycerol 3-phosphate:cytochrome c oxidoreductase E.C.1.1.1.95,αGPO, and L-malate: NAD+ oxidoreductase, E.C.1.1.1.37, m-MDH) obtained from several temperate and tropicalDrosophila species was examined by comparing their catalytic properties, which related to temperature (Km-Ea-Q10-Thermostability). MitochondrialαGPO or m-MDH obtained either from temperate or from tropical species was found to exhibit similar catalytic properties while for both cytosolic enzymes, theαGPDH and s-MDH, Km patterns were similar among species from the same thermal habitat and different between thermal habitats. In combination with other observations reported in the literature these facts support the view that the function, and probably the structure, of mitochondrial enzymes are better conserved in evolution than those of the corresponding enzymes found in the cytosol. It is proposed that the relative invariance of the mitochondrial enzymes structure is probably linked to a necessary relative invariance of molecular interactions inside the mitochondrion.
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    On the relation between genetic and environmental variability in animals (1982)
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    Journal of molecular evolution 18 (1982), S. 310-314 
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    ISSN: 1432-1432
    Keywords: Neutral mutation theory ; Natural selection ; Protein evolution ; Levene model ; Environmental variability ; Genetic variability ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If a phenotypic character is under stabilizing selection, the selective disadvantage of a nonoptimal genotype will decrease exponentially to zero as the proportion of phenotypic variation that is environmental in origin -V e /V p - increases. Under the modified mutation-drift hypothesis of genetic polymorphism, the proportion of mutations that are effectively neutral and average heterozygosity should increase with this ratio. Invertebrates, because of their small size, fast development, and low degree of homeostasis (relative to vertebrates), are expected to show a larger environmental component of phenotypic variation than vertebrates. This may help explain why invertebrates are in general more genetically variable than vertebrates and why, when laboratory populations ofDrosophila are maintained in heterogeneous environments, genetic variability is lost less rapidly than when they are kept in constant conditions.
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    Adjacent chromosomal regions can evolve at very different rates: Evolution of theDrosophila 68C glue gene cluster (1984)
    Springer
    Journal of molecular evolution 20 (1984), S. 251-264 
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    ISSN: 1432-1432
    Keywords: Drosophila ; Genome evolution ; 68C Glue gene cluster ; Drosophila melanogaster species subgroup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 68C puff is a highly transcribed region of theDrosophila melanogaster salivary gland polytene chromosomes. Three different classes of messenger RNA originate in a 5000-bp region in the puff; each class is translated to one of the salivary gland glue proteins sgs-3, sgs-7, or sgs-8. These messenger RNA classes are coordinately controlled, with each RNA appearing in the third larval instar and disappearing at the time of puparium formation. Their disappearance is initiated by the action of the steroid hormone ecdysterone. In the work reported here, we studied evolution of this hormone-regulated gene cluster in themelanogaster species subgroup ofDrosophila. Genome blot hybridization experiments showed that five other species of this subgroup have DNA sequences that hybridize toD. melanogaster 68C sequences, and that these sequences are divided into a highly conserved region, which does not contain the glue genes, and an extraordinarily diverged region, which does. Molecular cloning of this DNA fromD. simulans, D. erecta, D. yakuba, andD. teissieri confirmed the division of the region into a slowly and a rapidly evolving protion, and also showed that the rapidly evolving region of each species codes for third instar larval salivary gland RNAs homologous to theD. melanogaster glue mRNAs. The highly conserved region is at least 13,000 bp long, and is not known to code for any RNAs.
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    Effects of vitamin D and parathyroid hormone on cyclic AMP production by bone cells isolated from rat calvariae (1984)
    Springer
    Calcified tissue international 36 (1984), S. 320-326 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Vitamin D deficiency ; 1,25(OH)2D3 ; Parathyroidectomy ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Studies presented here were designed to investigate further the basis for an impaired cAMP response to parathyroid hormone (PTH) in osteoblastlike calvarial bone cells isolated from vitamin D-deficient rat pups. The goal was to perturb Ca, PTH, and vitamin Din vivo in order to see which factors might be responsible for the impairedin vitro bone cell cAMP response. Pups either were parathyroidectomized (PTX) 3–5 days, implanted with osmotic minipumps delivering high doses of PTH, given repeated, high doses of 1,25(OH)2D3, or were D-deficient (-D, i.e., born and suckled by D-deficient mothers). Osteoblastlike bone cells, isolated by sequential enzyme digestion and centrifugation, were exposed to PTH for 5 min in the presence of a phosphodiesterase inhibitor. In bone cells isolated from -D rat pups, both basal and PTH-induced cAMP accumulation were significantly lower than in +D bone cells. Earlier, we had shown that two daily injections of -D pups with 50 ng 1,25(OH)2D3 restores this reduced bone cAMP response of -D pups toward normal. In the present study, neither basal nor PTH-induced bone cell cAMP accumulation was affected by subjecting D-replete pups to PTX, PTH infusion, or repeated high doses of 1,25(OH)2D3 despite the fact that each treatment markedly changed serum Ca or serum immunoreactive PTH. The results indicate that the impaired bone cell cAMP response seen in -D pups is not a direct result of chronic hypocalcemia and that the “heterologous desensitization” seenin vitro with added 1,25(OH)2D3 could not be duplicated byin vivo treatment of +D pups with supraphysiologic doses of 1,25(OH)2D3. Finally the lack of alteration in the bone cell cAMP response to PTHin vitro after chronic PTH infusionin vivo fails to support the notion that the impaired response in -D bone cells can be explained entirely by “homologous desensitization” induced by high circulating levels of PTH in the hypocalcemic, -D rat pup.
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    URL: http://dx.doi.org/10.1007/BF02405337
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    Assessment of anin vivo diffusion chamber method as a quantitative assay for osteogenesis (1984)
    Springer
    Calcified tissue international 36 (1984), S. 77-82 
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    ISSN: 1432-0827
    Keywords: Osteogenesis ; Diffusion chambers ; Alkaline phosphatase ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The alkaline phosphatase activity and the calcium and phosphorus content of osteogenic tissue formedin vivo following the implantation of diffusion chambers loaded with rabbit bone marrow cells is reported. (In this study the term osteogenic includes osteoblastic and chondroblastic.) Chambers examined 14–70 days after implantation revealed progressive accumulation of mineral. Alkaline phosphatase activity increased until day 30 and declined thereafter. The osteogenic potential of the marrow cells decreased with increasing weight (age) of the cell donor rabbit when measured either as the percentage of chambers containing osteogenic tissue or as the amount of calcium, phosphorus, or alkaline phosphatase activity within the chambers. The results confirm that measurements of these parameters in tissue formed by cells incubated in diffusion chambersin vivo may be used as a method for assay of osteogenesis.
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    URL: http://dx.doi.org/10.1007/BF02405297
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    Blood/bone disequilibrium: IV. Reciprocal effects of calcium and phosphate concentrations on ion fluxes (1980)
    Springer
    Calcified tissue international 32 (1980), S. 229-236 
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    ISSN: 1432-0827
    Keywords: Bone ; Ion influxes ; Calcium ; Phosphate ; Exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Quantitative measurements were made of the ion fluxes of calcium and phosphate into and from calvaria (mouse or rat) when clamped in specially designed micro-Ussing chambers. The effects of varying concentrations of calcium were examined on the influx and efflux of calcium and of its counterion, phosphate. A comparable series of experiments was performed with varying phosphate concentrations. Both ions, as their concentrations increased, depressed their own influx, increased their own efflux, and significantly increased the equilibrium concentration, E/K, supported by the calvaria. Similarly, both ions, as their concentrations increased, affected the influx or efflux of their counterion only slightly but did depress the counterion's equilibrium level, E/K, significantly. In spite of these changes it was shown that calvaria effectively buffered the medium at physiological concentrations of calcium and phosphate. The buffering capacity, however, was small, and the balance, E/K, was modified by small uptake or loss of either ion. The small size of the interacting mineral pool was confirmed by direct measurement of the rapidly exchanging fractions of both calcium or phosphate. They were only ∼1% of the total ions present. The significance of these findings is discussed.
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    URL: http://dx.doi.org/10.1007/BF02408546
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    Calcitonin and parathyroid hormone in newborn infants with fracture of the clavicle (1984)
    Springer
    Calcified tissue international 36 (1984), S. 357-360 
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    ISSN: 1432-0827
    Keywords: Calcitonin ; Parathyroid hormone ; Calcium ; Newborn ; Fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Determinations of serum calcium (Ca), phosphorus (P), calcitonin (CT), and parathyroid hormone (PTH) were carried out in 36 full-term newborn infants with fracture of the clavicle (CF) and in 46 normal neonates (N). At the 6th hour of life the CF neonates demonstrated lower serum Ca and higher serum CT in comparison with normal infants. In the hours following, no significant differences between the two groups for the Ca levels were found, whereas serum CT remained significantly higher in the CF newborns at the 24th, 48th, and 72nd hour of life. Significant differences between normal and CF infants in the PTH serum levels were detected only at the 48th hour, when PTH was lower in the CF newborns. The results of this investigation indicate that the fracture of the clavicle is a significant and peculiar factor in stimulating CT secretion. Serum Ca level appeared to be controlled by CT rather than auto-regulating the secretion of the hormone.
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    URL: http://dx.doi.org/10.1007/BF02405346
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    Mineral loss in cortical and trabecular bone during high-dose prednisone treatment (1984)
    Springer
    Calcified tissue international 36 (1984), S. 269-273 
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    ISSN: 1432-0827
    Keywords: Bone loss (osteopenia) ; Calcium ; Corticosteroids (glucocorticosteroids) ; Fluoride ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To evaluate the effect of prednisone and triple treatment (sodium fluoride, calcium, and vitamin D) on trabecular and cortical bone serial bone mineral content (BMC) measurements were made at a metaphyseal (BMCD) and diaphyseal (BMCP) site on the forearm on 31 consecutive and previously bone-healthy patients scheduled for at least 24 weeks high-dose prednisone treatment. The patients were randomized into two further treatment groups: group I (n=16) received prednisone plus triple treatment and group II (n=15) received only prednisone. The two groups were similar with regard to age, sex, prednisone dose, and initial BMC. During 24 weeks treatment, BMCD (partially representing trabecular bone) and BMCP (mainly representing cortical bone) fell significantly and similarly, demonstrating that there is no preventive effect on bone mineral loss on the triple regimen. The BMC fall after 12 weeks was significantly more pronounced for metaphyseal (partially trabecular) than for diaphyseal (cortical) bone, whereas the values did not differ significantly after 24 weeks; this indicates a greater sensitivity to the hormone treatment of trabecular bone. In the entire group, the fall in BMC correlated positively with individual prednisone dose, significant at the diaphyseal site (r=0.39,P〈0.05), but not at the metaphyseal site (r=0.31, P=0.08). It is concluded that corticosteroid-induced osteopenia is a diffuse bone disease which affects trabecular as well as cortical bone, suggesting that BMC measured on the forearm reflects changes in bone mineral at other locations.
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    URL: http://dx.doi.org/10.1007/BF02405329
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    Changes in plasma bone GLA protein during treatment of bone disease (1982)
    Springer
    Calcified tissue international 34 (1982), S. 121-124 
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    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone Gla protein (BGP) was measured in the plasma by radioimmunoassay (RIA) during treatment of 59 patients with bone diseases including Paget's disease (N=9), primary hyperparathyroidism (N=25), chronic renal failure (N=20), and cancer involving bone (N=5). Plasma BGP was increased above normal in all patients. BGP decreased in the patients with Paget's disease following the acute and chronic administration of salmon calcitonin. Plasma BGP was higher in women then in men with primary hyperparathyroidism. Following parathyroidectomy, BGP decreased in both sexes but the decrease was significant in women only. Plasma BGP was increased in patients with renal osteodystrophy and did not change after hemodialysis. In the patients with bone cancer, plasma BGP decreased during treatment of the attendant hypercalcemia with salmon calcitonin. Although plasma BGP and serum alkaline phosphatase (AP) levels were generally correlated in these studies, there were examples of dissociation between the two. The measurement of plasma BGP appears to provide a specific index of bone metabolism that may in some circumstances be more sensitive than serum alkaline phosphatase measurement. However, further studies are necessary to establish the clinical value of plasma BGP measurement by RIA in the management of patients with bone diseases.
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    URL: http://dx.doi.org/10.1007/BF02411221
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    A fully automated and computerized system for simultaneous measurements of motility and phototaxis in Chlamydomonas (1983)
    Springer
    Archives of microbiology 135 (1983), S. 259-264 
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    ISSN: 1432-072X
    Keywords: Phototaxis ; Motility ; Flagellate ; Chlamydomonas ; Sodium azide ; Calcium ; A 23 187
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A fully automated and computerized method for simultaneous measurements of motility and phototaxis of unicellular flagellates is described. Both systems are directly coupled with a homocontinuous culture. The motility measuring apparatus is equipped with a video camera and recorder for simultaneous single cell behaviour studies. First results of studies on the effects of the phototaxis inhibitor sodium azide and the Ca2+ conducting ionophore A23 187 on motility and phototaxis of Chlamydomonas are reported and correlated with video observations. These results demonstrate that the described systems give informations of whether phototaxis or motility or both are inhibited by chemicals.
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    The role of calcium in stalk development and in phosphate acquisition in Caulobacter crescentus (1984)
    Springer
    Archives of microbiology 138 (1984), S. 140-152 
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    ISSN: 1432-072X
    Keywords: Caulobacter ; Prostheca development ; Stalk function ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calcium was found to stimulate stalk development in Caulobacter crescentus and to relieve the inhibition of development long known to be caused by phosphate. This suggested that phosphate inhibition could be attributed to its interaction with Ca2+, thereby depriving the cells of a factor that promoted development. Calcium was also found to promote phosphate acquisition by the cells, observed as acceleration of growth at extremes of phosphate concentration, as promotion of carbon-source utilization rather than storage, and as support for phosphate-dependent resistance to arsenate inhibition of growth. Cytological studies of dividing cells revealed that stalked siblings had greater access to exogenous phosphate for use in growth or for storage as polyphosphate, and that access of non-stalked sibling to phosphate was dependent on the length of the stalk of the dividing cell. It was concluded that the physiologic role of the stalk is enhancement of phosphate acquisition. The stimulatory role of calcium in this process was attributed to its support of stalk development and to its stabilization of internal membrane/cell envelope association within the cell-stalk juncture.
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    Elemental analysis of particles in fungal zoospores (1984)
    Springer
    Archives of microbiology 139 (1984), S. 102-104 
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    ISSN: 1432-072X
    Keywords: Fungus ; Zoospore ; Blastocladiella ; Allomyces ; Gamma ; Particle ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The elemental composition of gamma particles in zoospores ofAllomyces macrogynus andBlastocladiella emersonii was determined by use of energy dispersive X-ray analysis of glutaraldehyde fixed, thin section zoospores. Isolated preparations of gamma particles were also examined. Gamma particles contained no detectable elements. Similar sized, globular, electron dense cytoplasmic inclusions contained phosphorus and calcium. We suggest that previous studies assigning calcium and phosphorus to gamma particles may have been based on confusion of these two types of cytoplasmic inclusions.
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    URL: http://dx.doi.org/10.1007/BF00692722
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    Rhythmic dentinogenesis in the rabbit incisor: Allometric aspects (1980)
    Springer
    Calcified tissue international 32 (1980), S. 45-53 
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    ISSN: 1432-0827
    Keywords: Dentin ; Periodicity ; Allometry ; Calcium ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have described differences in the aspects of biological rhythms for calcium and sulfur deposition on the labial and lingual sides of the growing rabbit incisor, where growth occurs along a spiral axis. The calcium oscillations appear to be smoother on the labial side than on the lingual side. The lingual side is characterized by high-frequency rhythms with high amplitudes which possess the greatest percent of the power (Fourier analysis). These observations also reflect a difference in behavior of the mean Ca concentration across the labial and lingual sides. Sulfur rhythms on the labial side have higher amplitudes than those on the lingual side, but systematic differences in distribution of power between high and low frequencies is not as pronounced as in the case of Ca. The differences in Ca rhythms reflect differences in the growth rates of incisors on either side of the spiral axis. The labial side grows slightly faster than the lingual side, and its odontoblasts secrete Ca along the spiral axis and toward the pulp cavity at the same time. Thus the resultant direction of growth is more nearly opposite the extension of the occlusal end on the labial side, and Ca is consequently deposited over a wider area relative to that on the lingual surfaces. On the lingual side, Ca is deposited within a more limited area, and growth must therefore be continuous at high frequencies. The distribution of Ca on both sides of the tooth reflects these differences in growth rate and periodicity in two ways. First, given a unit area of tooth, the calcium concentration on the labial side is less than that of the lingual side. Second, whereas the calcium concentration on the labial side declines rapidly from the enamel-dentin junction to the pulp cavity, it is uniformly high across the lingual side because its growth is more continuous at high frequencies.
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    Effects of 1α-hydroxy vitamin D3 on the rachitic chick intestine: A comparison to the effects of 1,25-dihydroxyvitamin D3 (1980)
    Springer
    Calcified tissue international 32 (1980), S. 9-17 
    Details
    ISSN: 1432-0827
    Keywords: 1α-Hydroxy vitamin D3 ; 1,25-Dihydroxyvitamin D3 ; Calcium ; Transport ; Intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The timed sequence of events following the oral administration of 1α-hydroxy vitamin D3 (1αOHD3) to rachitic chicks was compared to that following a comparable dose of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). RNA polymerase activity was maximally increased 20% by 1αOHD3 within 1 to 2 h and returned to control values after 8 h. Alkaline phosphatase activity was stimulated by 4 h and was maximal (3- to 5-fold increase) at 24 h. Calcium binding protein (CaBP) was detected initially within epithelial cells at the proximal end of the villus (just above the crypt) 6 to 8 h after 1αOHD3 administration, in epithelial cells lining the proximal half of the villus by 24 h, and in epithelial cells along nearly the entire villus by 48 h. At no time did goblet cells contain CaBP. Serum calcium concentrations were significantly elevated in 2 h and maximal by 12 h (an increase of 3.6 mg/dl). Calcium accumulation by the intestinal mucosa in vitro was increased by 6 to 8 h and maximal (60% increase over controls) at 24 h. Phosphate accumulation by the intestinal mucosa in vitro was increased by 6 h and maximal (105% increase over controls) between 8 and 24 h. 1,25(OH)2D3 increased CaBP and calcium accumulation by 4 h, 2 h sooner than did 1αOHD3. 1,25(OH)2D3 decreased serum calcium levels and increased serum phosphate levels at 2 h unlike 1αOHD3. No difference in the effects of these compounds on alkaline phosphatase activity, RNA polymerase activity, and phosphate accumulation could be demonstrated. These results are consistent with the possibility that 1αOHD3 may not require conversion to 1,25(OH)2D3 for all of its biological effects.
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    URL: http://dx.doi.org/10.1007/BF02408517
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    In vitro perifusion for the study of parathyroid hormone secretion: Effects of extracellular calcium concentration and beta-adrenergic regulation on bovine parathyroid hormone secretion in vitro (1980)
    Springer
    Calcified tissue international 32 (1980), S. 19-27 
    Details
    ISSN: 1432-0827
    Keywords: Perifusion ; Parathyroid hormone ; In vitro ; Calcium ; Beta regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An in vitro perifusion system was used to study parathyroid hormone (PTH) secretion in response to calcium (Ca) and beta-adrenergic agents. Perifused parathyroid tissue responded to changes in Ca within the physiologic range during experiments up to 5 h. There was rapid secretory stimulation after exposure to low Ca, with the maximum response being observed at 20 min. Normal bovine glands showed a Ca-independent nonsuppressible component of PTH release at concentrations of Ca above physiologic. 1-isoproterenol produced rapid stimulation of PTH release, the response being blocked by a beta antagonist. The maximum secretory response to either low Ca (0.5 mM) or 1-isoproterenol (10−5 M) was enhanced when the two stimuli were applied simultaneously. The response to isoproterenol was blocked by raising Ca to 2.5 mM. Although d,l-propranolol (10−4 M) caused mild suppression of PTH release at a Ca of 1.25 mM, it did not cause additional suppression at 2.5 mM Ca nor did it decrease the response to 0.5 mM Ca stimulation. The secretory response of the gland to low Ca was sustained at a level more than double the baseline rate. The response to isoproterenol was more transient, with a return to or toward baseline secretion within 60 min. These results suggest that beta agonists and low Ca have separate but related mechanisms for stimulating PTH release and may affect different pools of hormone. The perifusion system described is a relatively simple technique for assessing the kinetics and interactions of various stimulators of PTH secretion.
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    Rhythmic dentinogenesis in the rabbit incisor: Circadian, ultradian, and infradian periods (1980)
    Springer
    Calcified tissue international 32 (1980), S. 29-44 
    Details
    ISSN: 1432-0827
    Keywords: Rabbit ; Dentin ; Calcium ; Sulfur ; Periodicity ; Circadian ; Ultradian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have identified a variety of biological rhythms involved in the apposition and mineralization of dentin in the rabbit incisor. Animals were injected during the day or night with lead acetate at 2-week intervals—to provide biological time markers in forming dentin—and transverse undecalcified sections of the lower incisors were prepared for electron microprobe analysis. The positions of the lead markers were identified, and the continuous distribution of calcium and sulfur was measured at 1 µm intervals between the markers. In thin sections stained with hematoxylin after decalcification, the widths of a series of structural increments (bands) were measured with an ocular micrometer. Fourier analysis of the data revealed spectra of structural and compositional rhythms with a range of periodicities which extended from a matter of hours [ultradian (〈24 h)] to days [infradian (〉24 h) and circadian (approximately 24 h)]. The structural and compositional rhythms appeared to be independent to the extent that they did not necessarily have the same periods, or amplitudes. Nor were there simple phase relationships between all of the rhythms. At some times, Ca and S fluctuations are inversely proportional (180° out of phase), but in other cases they are directly proportional or out of phase by varying degrees other than 180°. The analyses thus suggest that calcium and sulfur deposition (representing mineral and glycosaminoglycan deposition, respectively) are not simply inversely proportional, and that the hematoxylin-stained structural increments did not solely reflect differences in the distribution of the mineral components in dentin.
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    URL: http://dx.doi.org/10.1007/BF02408519
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    Effects of magnesium ion on parathyroid hormone secretion in vitro (1980)
    Springer
    Calcified tissue international 32 (1980), S. 201-206 
    Details
    ISSN: 1432-0827
    Keywords: Magnesium ; Parathyroid hormone ; Secretion ; In vitro ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In a well-defined in vitro perifusion system, the effects of extracellular magnesium concentration (Mg) on parathyroid hormone (PTH) secretion by bovine parathyroid tissue were examined. At Mg less than 0.8 mM, the ability of the glands to secrete hormone maximally in response to low calcium (Ca) stimulation was progressively impaired. Low Mg also impaired the ability of isoproterenol, dibutyryl cyclic AMP and theophylline to stimulate hormone release. The defect in hormone release at low Mg observed in vitro was analogous to the well-documented inhibition of secretion observed in vivo. Increases in Mg from 0 to 0.8 mM rapidly repaired the defect in hormone secretion. At Mg above 1.0 mM there was a Ca-like effect on hormone release, with a progressive decrease in secretion at increased Mg. Although its mechanism is not yet clear, the low Mg effect appears to impair principally the process of hormone release rather than its biosynthesis or storage.
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    Effects of weight loss on serum 1,25-(OH)2-vitamin D concentrations in adults: A preliminary report (1984)
    Springer
    Calcified tissue international 36 (1984), S. 139-144 
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    ISSN: 1432-0827
    Keywords: 1,25(OH)2-vitamin D ; Weight loss ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary During a review of 42 metabolic studies in healthy women and men we observed that serum 1,25-(OH)2-D concentrations were directly correlated to the observed daily changes in body weight (r=0.68;P〈0.001) and to caloric intake/kg/day (r=0.39;P=0.01). These relationships could not be accounted for by related and physiologically expected changes in serum Ca or iPTH concentrations. However, serum 1,25-(OH)2-D concentrations were observed to be inversely correlated to serum PO4 levels (r=−0.44;P=0.004). In addition, serum PO4 levels were inversely correlated to the daily changes in body weight (r=−0.40;P=0.009). Since dietary sodium intake averaged 142 mmol/day, it is unlikely that the observed changes in weight were the result of changes in salt and water balance. Thus it seems reasonable to speculate that serum 1,25-(OH)2-D concentrations may vary directly with energy balance, as reflected by changes in body weight. This effect may be mediated by alterations in PO4 metabolism. The accurate assessment of serum 1,25-(OH)2-D levels thus appears to require several measurements over time periods during which body weight is stable.
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    Hypervitaminosis D in the chick embryo: Comparative study on the activity of various vitamin D3 metabolites (1984)
    Springer
    Calcified tissue international 36 (1984), S. 392-400 
    Details
    ISSN: 1432-0827
    Keywords: Vitamin D ; Chick embryo ; Bone ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick embryos were injected in the yolk sac at various ages with various doses of different vitamin D3 metabolites. Serum concentrations of total calcium and inorganic phosphate were determined 24 h after the injection and histological and electron microscopic studies of the tibiae were conducted 3–6 days after. Confirming previous results, the injection of 1,25(OH)2D3 was found to produce significant hypercalcemia and hypophosphatemia. The dose required to produce these effects decreased with age: 100 ng on the 9th day, 50 ng on the 11th, and 10 ng on the 15th. This finding is interpreted as resulting from the fact that the specialized cells in the chorionic epithelium which are considered to be involved in mineral resorption from the shell differentiate between the 11th and 13th days. Although no bone changes were observed in embryos injected before the 11th day, a rim of unmineralized trabeculae (osteoid) was observed at the periphery of the cortex of the tibial diaphysis in the embryos which had been injected after that age. Thus, in embryos injected on the 11th day with 100 ng 1,25(OH)2D3, the trabeculae formed between the 11th and 14th day remained unmineralized until the 15th or 16th day at which time they completed their mineralization. In the embryos injected on the 14th day, the alterations were more severe and could be produced with doses 10 times smaller than those required when the injections were made on the 11th day. At all ages, the doses that produced an osteoid rim also induced hypercalcemia and hypophosphatemia. The electron microscopical study of the osteoid trabeculae showed that osteoblasts and osteocytes had normal cytological characteristics and that the bone matrix did not present changes other than the reduction in mineral deposition. While the above findings do not exclude a direct action of 1,25(OH)2D3 on bone cells as the mechanism of osteoid formation, they do underline the importance of the humoral changes at least as partial determinants of this phenomenon. The activities of various vitamin D metabolites were compared using as parameter the threshold-dose required to produce a rim of unmineralized trabeculae in the tibia of 14–15 days embryos (T-D). The most active metabolite appeared to be 1,25(OH)2D3 (T-D: 10 ng); it was followed by 1,24,25(OH)3D3 (T-D: 100 ng) and 1,25,26(OH)3D3 (T-D: 100 ng). Vitamin D3 itself (T-D: 100 µg), 25(OH)D3 (T-D: 2.5µg) and 24,25(OH)2D3 (T-D: 5 µg) produced similar responses but only when administered in much larger doses.
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    Effect of 1,25-dihydroxyvitamin D3 on osteopenia induced by prednisolone in adult rats (1982)
    Springer
    Calcified tissue international 34 (1982), S. 253-257 
    Details
    ISSN: 1432-0827
    Keywords: Prednisolone ; Calcium ; Bone ; Corticoid osteopenia ; Vitamin D metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Adult male rats were fed a diet containing 0.15% calcium, 0.3% phosphorus, and either 100, 50, or 20 mg of prednisolone per kg of diet. All these levels of prednisolone led to osteopenia, decreased intestinal absorption of calcium, slightly lower serum calcium and phosphorus, and a decreased level of serum 1,25-dihydroxyvitamin D3. Exogenous parenteral 1,25-dihydroxyvitamin D3 corrected steroid-induced changes in serum calcium and phosphorus, but could not completely correct the low intestinal calcium transport; nor did it prevent the development of osteopenia. The prednisolone-induced osteopenia seems at least in part to be caused by impaired intestinal calcium transport. The impaired calcium transport may be the result of low levels of 1,25-dihydroxyvitamin D3 and a direct effect of presnisolone on the intestine.
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    On the role of calcium in chemotaxis and oscillations of dictyostelium cells (1982)
    Springer
    European biophysics journal 9 (1982), S. 131-136 
    Details
    ISSN: 1432-1017
    Keywords: Chemotaxis ; Calcium ; Oscillation ; Dictyostelium ; Ionophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Migration of differentiated cells to a capillary containing cyclic AMP was enhanced in the presence of 1 mM CaCl2 and was virtually absent in the presence of 1 mM EGTA. Furthermore, the cells contracted and extended pseudopods to a capillary filled with the calcium ionophore A 23187. At short distances, migration to the tip of the capillary was observed. The ionophore also induced transient decreases of the optical density of suspended cells indicating changes of cell shape. These findings support the hypothesis that cyclic AMP-binding to cell surface receptors causes a local influx of calcium ions. These in turn lead to an increase of the cytosolic calcium concentration and subsequently to an activation of cell migration. Perturbing pulses of the ionophore induced permanent phase shifts of free-running light scattering oscillations. This result indicates that cytosolic calcium is an intrinsic component of the oscillatory system.
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    URL: http://dx.doi.org/10.1007/BF00539112
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    Calcium-mediated enhancement of the cyclic AMP response in cultured bone cells (1981)
    Springer
    Calcified tissue international 33 (1981), S. 409-416 
    Details
    ISSN: 1432-0827
    Keywords: Bone Cells ; Cyclic AMP ; Calcium ; Parathyroid hormone ; Prostaglandin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have examined the influence of extracellular Ca2+ on cyclic AMP metabolism in an osteoblast-enriched population of bone cells isolated from the calvaria of rat fetuses. The cyclic AMP1 response to stimulators of cyclic AMP formation (PTH and PGE2), but not basal cyclic AMP levels, increased progressively as the extracellular Ca2+ concentration was raised from 0.2 to 4.0 mM. The response to changes in extracellular Ca2+ were rapid (within 3.5 min), and the level of responsivity that characterized each Ca2+ concentration persisted for at least 6 h when the Ca2+ concentration was kept constant. The effect of Ca2+ spanned the entire time course of PTH action, was not accompanied by altered excretion of cyclic AMP from the cells, and was evident at low as well as at high hormone concentrations. Ca2+ augmented the action of PTH in the presence as well as in the absence of cyclic AMP phosphodiesterase inhibitors, and failed to decrease cyclic AMP phosphodiesterase activity in the short term. Mn2+ and, to a smaller degree, Ba2+ substituted for Ca2+ in promoting the cyclic AMP response to PTH. Verapamil, an inhibitor of Ca2+ penetration, blunted the Ca2+-mediated increments in the cyclic AMP response, and the divalent cation ionophore A23187 enhanced these increments. These results indicate that Ca2+ and other cations are positive effectors of the stimulated cyclic AMP response in isolated bone cells. Accumulation into an as yet unknown cellular compartment may be required for the cation effect. The data are most consistent with enhancement of adenylate cyclase reactivity as the mode of cation action.
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    URL: http://dx.doi.org/10.1007/BF02409464
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    Effects of a bone resorptive factor from human cancer ascites fluid on rat bone cell calcium and cyclic AMP (1980)
    Springer
    Calcified tissue international 30 (1980), S. 191-197 
    Details
    ISSN: 1432-0827
    Keywords: Bone cells ; Cyclic AMP ; Calcium ; Ascites fluid resorptive protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of a bone resorptive protein isolated from human cancer ascites fluid on bone cell calcium and cyclic AMP were studied with fetal rat cells. The osteoclast-activating factor increased bone cell calcium uptake at 37°C and 4°C with no direct effects on calcium efflux. Concentrations of the resorptive factor that increased in vitro bone resorption and cell calcium uptake had no effect on cyclic AMP. The effects of the protein on calcium uptake were not specific for bone cells, and large increases were also observed in isolated fetal rat skin cells. These studies suggest that increases in the permeability of the cell membrane to calcium are involved in the mechanism of action of the ascites fluid resorptive protein.
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    URL: http://dx.doi.org/10.1007/BF02408627
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    In vitro effects of vitamin D3 metabolites on rat calvaria cAMP content (1980)
    Springer
    Calcified tissue international 30 (1980), S. 209-216 
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    ISSN: 1432-0827
    Keywords: Calvarium ; cAMP ; Vitamin D3 metabolites ; Calcium ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Results from in vitro works suggest that 1,25- and 24,25-dihydroxyvitamin D3 (1,25-(OH)2D3 and 24,25-(OH)2D3) act on bone via different mechanisms. The present investigation was performed to study the effect of these two metabolites and of their precursor 25-hyxdroxyvitamin D3 (25-(OH)D3) on bone cAMP content in vitro. Rats' paired half calvaria were incubated under sterile conditions with one vitamin D3 derivative (10−13 to 10−9 M) or with ethanol (0.005 ml for 15 min to 24 h in 1 ml medium containing 0, 0.2, 1, 2, or 3 mM calcium. In some experiments: (a) cycloheximide (10−5M) was added simultaneously with the vitamin D3 metabolites; (b) 1–84 bPTH (5 × 10−8 M) was added for 5 or 15 min at the end of the 24 h incubation. Calvaria were immersed in 1 ml TCA 5% 4°C and homogenized. The cAMP was extracted with diethylether and measured by a competitive protein binding assay. Results bring further evidence for a particular effect of low doses of 24,25-(OH)2D3 (10−9 to 10−12M) and of 25-(OH)D3 (10−9 to 10−11M) on bone, different from that of 1,25-(OH)2D3: cAMP content was higher in 24,25-(OH)2D3- or 25-(OH)D3-treated and lower in 1,25-(OH)2D3-treated calvaria than in ethanol-treated ones with 1 mM calcium. The 1,25-(OH)2D3 effect persisted in calcium-free medium whereas 25-(OH)D3 and 24,25-(OH)2D3 effects could not be observed with 0 mM nor with 3 mM calcium. The required duration of the preincubation (over 1 h) as well as the inhibitory action of cycloheximide may suggest an involvement of protein synthesis in the vitamin D3 metabolites effects. Neither 1,25-(OH)2D3 nor 24,25-(OH)2D3 affected the PTH-induced increase in bone cAMP content.
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    URL: http://dx.doi.org/10.1007/BF02408630
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    Oral 1,25(OH)2D3: An effective prophylactic treatment for glucocorticoid osteopenia in rats (1983)
    Springer
    Calcified tissue international 35 (1983), S. 107-110 
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    ISSN: 1432-0827
    Keywords: Calcium ; Glucocorticoid ; Vitamin D ; Osteoporosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Eighty-eight adult male Sprague-Dawley rats were given a diet with either (a) 0.5% Ca and 0.6% P or (b) 0.01% Ca and 0.6% P. Osteopenia was created by adding prednisolone to the diet. The prophylactic effect of oral 1,25(OH)2D3 on the osteopenia was studied. It was found that prednisolone osteopenia in the rat was associated with defective Ca absorption. By giving an oral dose of 1,25(OH)2D3, it was possible to maintain normal Ca absorption during prednisolone treatment and to prevent the bone loss. No significant hypercalcemia or any kidney calcifications were seen. These results are in contrast to earlier findings, in which subcutaneous administration of 1,25(OH)2D3 failed to prevent prednisolone osteopenia because of its tendency to increase bone resorption.
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    URL: http://dx.doi.org/10.1007/BF02405014
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    31P nuclear magnetic resonance spectroscopic evidence for ternary complex formation of fetal dentin phosphoprotein with calcium and inorganic orthophosphate ions (1983)
    Springer
    Calcified tissue international 35 (1983), S. 815-818 
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    ISSN: 1432-0827
    Keywords: 31P NMR spectroscopy ; Phosphoprotein ; Dentin ; Calcium ; Inorganic orthophosphate ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The single phosphoprotein of fetal calf dentin, having a molecular weight of approximately 94,000 and a phosphorus content of 8% (w/w), was examined by31P NMR spectroscopy. The single resonance at 3.7 ppm at pH 10 and its chemical shift during acid titration established the phosphomonoester nature of the organic phosphorus moiety. During titration of the phosphoprotein with CaCl2 in the presence of inorganic orthophosphate ions, line broadening for the orthophosphate resonance was both phosphoprotein- and calcium-dependent, indicating ternary complex formation. The data indicate that the phosphoprotein of fetal calf dentin binds both calcium and inorganic orthophosphate ions and therefore has the requisite physical chemical properties necessary for it to facilitate the heterogeneous nucleation of a Ca-PO4 solid phase from solution during tissue mineralization.
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    URL: http://dx.doi.org/10.1007/BF02405129
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    Electromagnetic modulation of biological processes: Influence of culture media and significance of methodology in the Ca-uptake by embryonal chick tibiain vitro (1984)
    Springer
    Calcified tissue international 36 (1984), S. 167-174 
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    ISSN: 1432-0827
    Keywords: Electromagnetic field ; Bicarbonate ; Phosphate ; Calcium ; Fluoride ; Osteogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present studies are aimed at establishing molecular correlations in the interaction of very low frequency electromagnetic fields with biological systems. Ca-uptake by chick embryo tibia rudiment in short-term culture was a useful model. Tibiae of 8- to 10-day-old chick embryos were incubated 60 min in simplified culture media in the presence of45Ca at 37.5±0.5°C either inside or outside pulsating electromagnetic fields. Radioactivity count in the medium was the most accurate method for determining Ca-uptake by the rudiment. The effect of the fields on the Ca-uptake depended markedly on the chemical composition of the culture medium: bicarbonate was indispensable; glucose or sucrose was important; phosphate was potentiating; ethanol, Mg2+, and NaF were stimulating. The field had no effect in (a) blank medium without tibia, (b) tibiae that had been altered by fixation with aqueous glutaraldehyde, (c) nonliving artificial systems endowed with great or small ion sorption capacity. The unique bicarbonate effect with living systems and the passive behavior of nonliving ion sorbing systems prompt the suggestion that the electromagnetic field probably couples with specific processes, such as a bicarbonate-dependent Ca2+ ATPase and the active ion transport, at the cell membrane level. The molecular mechanisms remain to be established.
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    URL: http://dx.doi.org/10.1007/BF02405313
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    Calcium distribution in freeze-dried enamel organ tissue during normal and altered enamel mineralization (1984)
    Springer
    Calcified tissue international 36 (1984), S. 596-603 
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    ISSN: 1432-0827
    Keywords: Calcium ; Ameloblasts ; X-ray microanalysis ; Transport ; Frozen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Energy dispersive X-ray microanalysis was applied to freeze-dried blocks of enamel organ tissue to determine levels of calcium in various celular regions. The tissue blocks were dissected free from adjacent forming enamel following injection of cobalt or fluoride ions, both of which temporarily inhibit enamel mineralization. In all control and experimental specimens there was an increasing gradient of calcium from the stratum intermedium cells to the distal ends of the ameloblasts. Calcium levels were significantly reduced near the distal ends of the ameloblasts following cobalt or fluoride injection as compared with controls. It is suggested that evidence of an intercellular buildup of calcium near the distal ends of the ameloblast supports a controlling function of these cells. The changes in calcium levels are correlated with alterations in mineralization known to occur in the adjacent enamel of the model systems employed.
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    Ultrastructure, function and composition of smooth muscle (1983)
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    Annals of biomedical engineering 11 (1983), S. 579-588 
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    ISSN: 1573-9686
    Keywords: Smooth muscle ; Electron probe analysis ; Calcium ; Myosin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Filamentous myosin is present in both relaxed (myosin light chains unphosphorylated) and contracted (light chains phosphorylated) vascular smooth muscle. The organization of myosin and actin filaments and the insertion of the latter on cytoplasmic and plasma membrane bound dense bodies is consistent with a mini sarcomere-like organization and a sliding filament mechanism of contraction in smooth muscle. Mitochondria are high capacity, low affinity Ca stores in smooth muscle. They do not play a role in the regulation of cytoplasmic Ca2+ at physiological levels. The localization and Ca content of the junctional sarcoplasmatic reticulum (SR) is consistent with this organelle being the major intracellular source of activator Ca released by excitatory transmitters. Repeated contractions in the absence of extracellular Ca2+ (thought to represent recycling of intracellular activator Ca2+) can be demonstrated if the excitatory agent is not allowed to remain in contact with the smooth muscle throughout relaxation; the demonstration of “recycling” is facilitated if the efflux of cellular Ca2+ is blocked. The rise in total cytoplasmic calcium measured with electron probe analysis during a maintained (30 min) contracture in rabbit portal-anterior mesenteric vein smooth muscle (∼0.9 mmol/kg dry cytoplasm) is greater than the amount of Ca that could be bound to calmodulin.
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    URL: http://dx.doi.org/10.1007/BF02364087
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    Total body bone mineral and lean body mass by dual-photon absorptiometry (1981)
    Springer
    Calcified tissue international 33 (1981), S. 365-368 
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    ISSN: 1432-0827
    Keywords: Absorptiometry ; Osteoporosis ; Spinal bone ; Bone mineral content ; Neutron activation ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dual-photon absorptiometry using153Gd (44 and 100 keV) was used to measure the bone mineral content (BMC) of the trunk and of the total body (TBBM) in 7 volunteers with no overt bone disease. These values were compared to those obtained with partial-body neutron activation of calcium (trunk Ca). The trunk Ca seemed to represent best a 60 × 30 cm area; the correlation coefficient with the corresponding BMC in that area was 0.97 (SEE ⋍ 7%). Trunk Ca was also highly correlated with TBBM (r=0.96; SEE=8%) and with radius BMC (r=0.92; SEE=11%), but the correlations with the BMC of smaller subareas of the trunk were lower (r⋍0.9; SEE ∼ 12%). The BMC of the lumbar spine was only moderately correlated with trunk Ca, radius BMC and TBBM (r ∼ 0.82; SEE ∼ 18%), and only slightly more associated with trunk BMC (r ∼ 0.88; SEE ∼ 14%). The BMC of the combined lumbar-thoracic spine showed higher correlations with trunk Ca, radius BMC and TBBM (r ∼ 0.87; SEE ∼ 13%), and trunk BMC (r=0.93; SEE ∼ 10%). An accurate and sensitive measure of spinal status requires a direct measurement of that area.
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    Effects of age and sex on the regulation of plasma 1,25-(OH)2-D by phosphorus in the rat (1981)
    Springer
    Calcified tissue international 33 (1981), S. 477-484 
    Details
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D ; Calcium ; Phosphorus ; Sex ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dietary phosphate deprivation in women, but not men, is accompanied by a fall in plasma PO4 and a rise in plasma 1,25-(OH)2-vitamin D concentrations. In contrast, young male rats exhibit a fall in plasma PO4 and a rise in plasma 1,25-(OH)2-D concentrations in response to PO4 deprivation. To evaluate whether age and sex influence basal plasma 1,25-(OH)2-D levels and their regulation by PO4 deprivation, plasma 1,25-(OH)2-D, PO4, and Ca levels were measured in male and female rats ranging in age from 6 weeks to 6 months while they were eating normal or low PO4 diets for 1 to 16 days. Similar observations were also made in 6-week-old castrated male and female rats, males replaced with testosterone, and females replaced with estradiol. Basal plasma 1,25-(OH)2-D levels were higher in 6-week-old males (228±76 pmol/l) than in 6-week-old females (148±62 pmol/l;P〈0.01) and declined by age 11 weeks to stable levels averaging about 100 pmol/l without sex difference. Dietary PO4 deprivation resulted in a three-to fourfold increase in plasma 1,25-(OH)2-D concentrations regardless of age and sex, accompanied by a correlated rise in serum Ca concentrations. Castration of 6-week-old males and females eliminated the sex difference in basal plasma 1,25-(OH)2-D levels and appeared to enhance the elevation of plasma 1,25-(OH)2-D concentrations in response to PO4 deprivation in females. Although gonadal hormones may modify basal plasma 1,25-(OH)2-D levels, they are not required for the augmentation of plasma 1,25-(OH)2-D levels in response to PO4 deprivation.
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    URL: http://dx.doi.org/10.1007/BF02409477
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    Factors in response to treatment of early postmenopausal bone loss (1981)
    Springer
    Calcified tissue international 33 (1981), S. 575-581 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Vitamin D ; Bone mineral ; Estrogen ; Aging ; Thiazide ; Fluoride ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone mineral content (BMC) was measured by125I photon absorptiometry every 3 months in 264 normal females (45–54 years) over a 2-year period together with serum samples for calcium, phosphate, magnesium, creatinine, alkaline phosphatases, potassium, and protein. A 48-h urinary calcium and creatinine measurement was obtained. The subjects were divided into 7 treatment groups and 3 placebo groups. Five of the treatments (thiazide, vitamin D3, fluoride + vitamin D3, fluoride, and 1αD3) were ineffective at the doses used; the annual loss of compact bone was 1.5–2.2% (-X=1.8%), similar to the loss seen with placebos. Estrogen and estrogen + thiazide, in contrast, produced a 1.34% annual increase of BMC. The subjects were divided into groups with low, medium, and high initial BMC. Also, individual regressions for bone change were calculated and the subjects were divided into groups of responders, maintainers, and losers (annual change of 〉0%, 0 to −1%, and 〉−1%, respectively). The initial BMC status did not consistently affect bone or biochemical responses to the therapeutic agents. Estrogen was effective even in subjects with high BMC, whereas the other agents did not inhibit bone loss even in subjects with low initial BMC. Virtually all subjects responded to estrogen positively; in contrast we could not identify a subset of “responders” with any of the other treatments. Time since menopause appeared to influence the bone changes, although it was not a significant effect given the sample size. Bone loss in groups not treated with estrogens was 2%/year at 20 months after menopause with a decline to 1.3%/year at 45 months post-menopause. There was no apparent decline in the bone response to estrogen during the first 4 years after menopause, and in fact bone response tended to increase with time.
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    Ultrastructural localization of calcium in the mandibular condylar growth cartilage of the rat (1980)
    Springer
    Calcified tissue international 30 (1980), S. 27-34 
    Details
    ISSN: 1432-0827
    Keywords: Ultrastructure ; Calcium ; Cartilage ; Vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The potassium pyroantimonate technique was utilized for the selective subcellular localization of calcium in the mandibular condylar cartilage of 1-day-old rats. Electron dense calcium pyroantimonate precipitates were localized principally in mitochondria and at the cell membrane of the chondrocytes. In addition, small intracellular vesicles 0.1–0.2µm in diameter were observed in proximity to the cell membrane of chondrocytes of the mid-hypertrophic zone. The results suggest that these vesicles were being extruded from the cell into the extracellular matrix. Energy-dispersive analysis by X-rays confirmed that calcium is the principal cation of the electron-dense precipitates.
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    Effects of pyrophosphate and diphosphonates on the dissolution of hydroxyapatites using a flow system (1980)
    Springer
    Calcified tissue international 31 (1980), S. 153-159 
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    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Dissolution ; Pyrophosphate, Diphosphonates ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Pyrophosphate and diphosphonate ions have been said to diminish the dissolution of hydroxyapatite crystals, because they lower the equilibrium concentrations of calcium and phosphate ions in the bulk solution around hydroxyapatite crystals in a closed system. However, in a closed system these effects are not necessarily due to an effect on dissolution alone. In this paper we have used a continuous flow system to study the effects of pyrophosphate and two diphosphonates, ethane-1-hydroxy-1,1-diphosphonate and dichloromethane diphosphonate, on the dissolution of hydroxyapatite. All three compounds decreased markedly the rate of dissolution of hydroxyapatite as well as the exchangeable pools of calcium and phosphate ions around the cystals.
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    Characterisation of the Egeria densa Planch. leaf symplast (1983)
    Springer
    Planta 158 (1983), S. 320-328 
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    ISSN: 1432-2048
    Keywords: Calcium ; Egeria ; Fluorescent probe ; Ions, group II ; Symplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hydrophyllic dyes fluorescein glutamic acid, fluorescein glutamylglutamic acid (F(Glu)2), fluorescein hexaglycine, fluorescein leucyldiglutamyl-leucine and 6-carboxyfluorescein are unable to pass the plasmalemma in leaves of E. densa. However, when injected into single cells the dye conjugates of molecular weight 665 dalton or less move freely from cell-to-cell. This intercellular movement presumably occurs via the plant symplast. Movement of F(Glu)2 from the injected cell occurs with greatly reduced frequency when Ca2+, Mg2+ or Sr2+ are injected into the cell immediately prior to the dye. The fraction of dye injections leading to movement declines with increasing group II ion concentration in the electrode tip, up to 10 mM. Sodium and K ions do not affect dye movement. When dye injection is delayed 30 min after Ca2+ injection, dye movement is no longer inhibited. Thus the cells recover from the Ca2+ injection, indicating that the ion does not cause major cell damage. Recovery from Mg2+ injection is not complete within 60 min. Treatment of leaves with chemicals expected to raise the concentration of free intracellular group II ions, notably the mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxyphenyl hydrazone, the inhibitor of mitochondrial Ca2+ uptake trifluralin, or the ionophore A23187 also inhibits dye movement, while the calmodulin inhibitor trifluoperazine does not. Cytoplasmic streaming is inhibited by Ca2+ or Mg2+ injection and by the metabolic inhibitors. However when streaming is stopped by cytochalasin B, dye movement is not inhibited. Hence steaming is not necessary for dye movement. Thus the cytoplasmic concentration of free group II ions may directly regulate the permeability of the plant symplast.
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    Adaptive strategies in natural populations of Drosophila (1980)
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    Theoretical and applied genetics 57 (1980), S. 257-266 
    Details
    ISSN: 1432-2242
    Keywords: Drosophila ; Ethanol ; Climatic races ; Desiccation ; Development times
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Adult tolerance of ethanol vapour in a closed system containing 12% ethanol in solution, decreases in a cline from southern to northern Australia. However a Darwin population is more tolerant than predicted from its latitude. Ethanol tolerance races in Australia have almost certainly evolved within the last 100–150 years, because of resource unavailability prior to that time. Within populations, variation among isofemale strains is lowest in the climatically extreme southern Melbourne (37°S) and northern Darwin and Melville I. (11–12°S) populations. This suggests low resource diversity within extreme populations compared with the climatically less extreme Brisbane (28°S) and especially Townsville (19°S) populations. For desiccation resistance, the population rankings are: Darwin Melbourne 〉 Townsville 〉 Brisbane Melville I. and for development time, rankings are similar: Darwin Melbourne 〈 Townsville 〈 Brisbane Melville I. Therefore resource utilization heterogeneity is greatest in populations not greatly stressed by desiccation and where development times are extended. In total therefore, the utilization of a diversity of resources is a feature of populations tending somewhat towards a K-strategy; this is emphasized by the relative heterogeneity among isofemale strains of these populations for desiccation resistance and to a lesser extent development times. The D. melanogaster gene pool can be viewed as made up of climate-associated races. Since the ethanol tolerances of adjacent (and climatically similar) Darwin and Melville I. are very different, resource utilization races may occur within climatic races. Such a mosaic of resource utilization races are more likely in climatically extreme than in optimal habitats.
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    Control of plasma 1,25-(OH)2-vitamin D concentrations by calcium and phosphorus in the rat: Effects of hypophysectomy (1981)
    Springer
    Calcified tissue international 33 (1981), S. 485-488 
    Details
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D ; Hypophysectomy ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mechanism by which dietary phosphate deprivation elevates plasma 1,25-(OH)2-D levels is not known. To evaluate the role of the pituitary in regulating plasma 1,25-(OH)2-D concentrations, the responses of plasma 1,25-(OH)2-D to dietary phosphate deprivation and, separately, to dietary calcium deprivation were evaluated in intact and hypophysectomized male rats. Among intact and hypophysectomized rats eating normal diets, plasma 1,25-(OH)2-D levels averaged 228±76 and 148±62 pmol/1, respectively (P〈0.01). During dietary phosphate deprivation, plasma 1,25-(OH)2-D levels rose to 1160±260 in intact rats and fell to 90±26 pmol/l in hypophysectomized rats (P〈0.001). By contrast, during dietary calcium deprivation, plasma 1,25-(OH)2-D levels rose in both intact and hypophysectomized animals to 856±107 and 742±279 pmol/l, respectively (NS). In response to dietary phosphate deprivation, serum calcium concentrations rose as 1,25-(OH)2-D concentrations rose in intact rats but remained at control levels in hypophysectomized rats. These results support the hypothesis that a pituitary hormone acting either directly or indirectly on the kidney mediates the increase in plasma 1,25-(OH)2-D during dietary phosphate deprivation. The hypercalcemia that occurs in rats during dietary phosphate deprivation appears to depend on the elevation of plasma 1,25-(OH)2-D.
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    Calcium homeostasis and bone pathology in magnesium deficient rats (1980)
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    Calcified tissue international 31 (1980), S. 231-238 
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    ISSN: 1432-0827
    Keywords: Magnesium ; Bone ; Calcium ; Parathyroid gland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calcium homeostasis and bone pathology were studied in weanling rats fed a low (70 ppm) magnesium diet for 2–21 days. The rats developed significant, progressive hypercalcemia after 6 days on the diet. The increase in blood calcium was accompanied by progressive hypoactivity of the parathyroid gland (PTG), as determined by histologic and morphometric analyses. Thus hyperactivity of the PTG could not have been responsible for the hypercalcemia observed. Histologic examination of femora and humeri from magnesium-deficient rats showed progressive subperiosteal hyperplasia, consisting of undifferentiated osteoprogenitor cells and fibrous tissue, after 7 days of deficiency. The presence of unmineralized osteoid tissue in the metaphyses indicated that mineralization was not proceeding normally. The alterations in differentiation of osteoprogenitor cells, together with the failure of mineralization, resulted in significantly lower rates of bone formation (as measured by fluorochrome labeling) in the magnesium-deficient rats. Basophilic cementing lines and inactive osteocytes in the cortices of bones from magnesium-deficient rats indicated that bone resorption was also severely reduced in magnesium deficiency. We postulate that bone magnesium depletion (66% by day 21) has a direct negative effect on osteoblastic and osteocytic activity, and may explain, in part, the decreased responsiveness of bone to parathyroid hormone (PTH) that has been observed in magnesium-deficient animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407186
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  • 92
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    Equilibrium dialysis and ultrafiltration studies of calcium and phosphate binding by human salivary proteins. Implications for salivary supersaturation with respect to calcium phosphate salts (1982)
    Springer
    Calcified tissue international 34 (1982), S. 531-538 
    Details
    ISSN: 1432-0827
    Keywords: Saliva ; Calcium ; Phosphate ; Ion-binding ; Supersaturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Previous ultrafiltration studies indicated that up to one-half of the calcium and two-thirds of the phosphate in human salivary secretions may be bound by salivary proteins. Since this binding is an important variable in determining the extent of salivary supersaturation with respect to calcium phosphate salts, and since the amount of binding reported is surprisingly large, calcium and phosphate ion-binding by salivary macromolecules has been reexamined. From experiments using equilibrium dialysis, it was found that (1) the fraction of salivary calcium involved in macromolecular complexes ranges from a few percent for unstimulated secretions, to no more than about 10% for stimulated glandular salivas, and (2) salivary proteins do not bind phosphate ions to any significant extent. These findings, and experiments using an improved ultrafiltration membrane, indicate that the earlier results were artifacts of the ultrafiltration technique. Fractionation of salivary proteins, followed by equilibrium dialysis measurements, showed that the anionic proline-rich proteins and a basic proline-rich glycoprotein are responsible for most of the calcium binding now observed. The finding that macromolecular complexes of salivary calcium and phosphate have been overestimated in the past, leads to the conclusion that salivary calcium and phosphate ion activities in stimulated salivary secretions may be up to 50 to 100% higher than previously thought. Revised values were therefore used to recalculate the degree of salivary supersaturation with respect to calcium phosphate salts. The results indicate that stimulated salivary secretions are supersaturated with respect to dicalcium phosphate dihydrate; this is a substantially greater degree of supersaturation than previously reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411299
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    Benzo(B)Thiophene-2-Carboxylic acid: Calcium uptake and cyclic AMP production in isolated bone cells (1984)
    Springer
    Calcified tissue international 36 (1984), S. 194-199 
    Details
    ISSN: 1432-0827
    Keywords: Benzo(B)Thiophene-2-Carboxylic Acid ; Bone cells ; Calcium ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of the present study was to investigate the mechanism of action on bone of Benzo(B)Thiophene-2-Carboxylic Acid (BL-5583). BL-5583, at a dose range of 0.01–100 µg/ml, inhibited spontaneous as well as A23187 and PTH-induced bone resorption in tissue culture. This compound also decreased calcium uptake in both osteoclastic and osteoblastic enriched bone cell populations obtained by sequential collagenase digestion of 1–2 day newborn rat calvariae. The decrease occurred after a 5 min. incubation with45Ca and BL-5583. The effective dose range was 0.01–100 µg/ml. No effect on leucine incorporation or lactic acid production by bone cells was observed. BL-5583 also induced a transient decrease in calcium uptake in skin cells isolated from fetal rats by collagenase digestion, suggesting a lack of tissue specificity for this compound. No effect on cyclic AMP in isolated bone cells was observed with the same dose range that produced a calcium effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405317
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  • 94
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    In vitro precocious accumulation of calcium and matrix vesicles formation in young cartilage cells: Specific effects of corticosteroids (1984)
    Springer
    Calcified tissue international 36 (1984), S. 702-710 
    Details
    ISSN: 1432-0827
    Keywords: Corticosteroids ; Cartilage ; Organ culture ; Calcium ; Matrix vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present study examined the effects of various corticosteroid and noncorticosteroid hormones upon the ultrastructure of chondroprogenitor cells and chondroblasts in an organ-culture system of late fetal condylar cartilage. Corticosteroids, (triamcinolone acetonide, dexamethasone, corticosterone) at concentrations of 10−6–10−8M stimulated markedly a precocious formation of matrix vesicles by chondroblasts. This stimulation was accompanied by a significant accretion of calcium complexes intra- and extracellularly in both the chondroprogenitor cell population and chondroblastsin vitro, as well as in the newly induced matrix vesicles. Nonglucocorticoid steroids (progesterone, estradiol, testosterone, cortexolone) did not evoke similar effects. Progesterone and testosterone, however, seemed to adversely affect the ultrastructure of the cartilage cells, whereas estradiol appeared to have a favorable effect on the morphology of cultured condylar cartilage.
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    URL: http://dx.doi.org/10.1007/BF02405393
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  • 95
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    Effect of phosphate on phosphatidylserine-mediated calcium transport (1982)
    Springer
    Calcified tissue international 34 (1982), S. 43-48 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Phosphatidylserine ; Transport ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Experiments were performed to study the effect of inorganic phosphate (Pi) on phosphatidylserine-mediated Ca2+ transport utilizing two- and three-compartment lipid-aqueous phase model systems. When the three-compartment model was used, the rate of Ca2+ transport from an aqueous donor compartment to an aqueous receiver compartment, separated by a nonaqueous phospholipid phase, was determined. This experiment showed that the rate of Ca2+ transport was proportional to the phosphatidylserine concentration and the pH. Pi modulated the rate of Ca2+ transport; even when the Pi concentration of the donor aqueous phase was low, there was a marked enhancement of transport. To determine whether the Pi-mediated rise in the Ca2+ transport rate was due to an increase in the uptake of Ca2+ into the lipid phase, or to an increase in the ability of the lipid phase to release Ca2+, a two-compartment model was used. It was found that the ability of the phosphatidylserine phase to take up Ca2+ increased as the Pi concentration of the aqueous donor phase was raised. With the increase in Ca2+ uptake there was a concomitant elevation in the rate of Ca2+ transport into an aqueous receiver phase. However, Pi did not stimulate Ca2+ release from the phosphatide. Thus it was concluded that Pi enhanced the interaction between Ca2+ and phosphatidylserine, possibly by forming a Ca-phospholipid-Pi complex. Once this interaction had taken place, Ca2+ release into the aqueous receiver compartment was independent of the Pi concentration.
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    URL: http://dx.doi.org/10.1007/BF02411207
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  • 96
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    Genetic sexing in Drosophila melanogaster using the alcohol dehydrogenase locus and a Y-linked translocation (1981)
    Springer
    Theoretical and applied genetics 59 (1981), S. 23-24 
    Details
    ISSN: 1432-2242
    Keywords: Genetic sexing ; Alcohol dehydrogenase ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By incorporating ethanol (4% v/v) into the larval rearing medium of a specially constructed Drosophila melanogaster strain it was possible to produce only male adults; the female larvae died. In this strain, the male determining chromosome was linked with a positive Alcohol dehydrogenase (ADH) allele by a translocation. The females were homozygous for the null allele and hence sensitive to ethanol. This genetic sexing method is discussed in relation to its use in the genetic control of insects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275770
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    Underreplication during polytenization? (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 193-199 
    Details
    ISSN: 1432-2242
    Keywords: Drosophila ; Polytene nuclei ; Underreplication ; Polytenization ; Cytophotometry ; Heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Recent cytophotometric DNA determinations and results of labeling experiments are compared with results of biochemical experiments concerning larval polytene salivary gland nuclei of Drosophila melanogaster. Recent publications (Dennhöfer 1981; 1982 a, b) demonstrate that methodological errors both in hydrolysis of the DNA before Feulgen reaction and in interpretation of the cytophotometric values give raise to the hypothesis of heterochromatic underreplication during polytenization. It is concluded also that methodological difficulties cause the absence of polytene SAT-DNA in biochemical centrifugation experiments since, because of different solubilities of eu- and heterochromatic DNA, the latter is not resolved in DNA isolation procedures from polytene nuclei.
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    URL: http://dx.doi.org/10.1007/BF00303991
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  • 98
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    Calcium and gibberellin-induced elongation of lettuce hypocotyl sections (1981)
    Springer
    Planta 152 (1981), S. 450-456 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Cell elongation ; Gibberellin ; Lactuca ; pH and growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between calcium ions and gibberellic acid (GA3)-induced growth in the excised hypocotyl of lettuce (Lactuca sativa L.) was investigated. The short-term kinetics of growth responses were measured using a linear displacement transducer. Test solutions were added either as drops to the filter paper on which the hypocotyl stood (“non-flow-past”) or by switching solution flowing past the base of hypocotyl (“flow-past”), resulting in differences in growth behavior. Drops of CaCl2 added at a high concentration (10 mM) inhibited growth within a few minutes. This inhibition was reversed by ethylenediaminetetraacetic acid (EDTA). Drops of EDTA or ethyleneglycol-bis(2-aminoethylether)-tetraacetic acid caused a rapid increase in growth rate. Growth induced by EDTA was not further promoted by GA3. A continuous H2O flow resulted in growth rates comparable to those in response to GA3. Addition of CaCl2 to the flow-past medium inhibited growth and this inhibition was reversed by a decrease in CaCl2 concentration. The growth rate was found to be a function of CaCl2 concentration. When a constant CaCl2 concentration was maintained by the flow-past medium, a shift in pH from 5.5 to 4.25 had no obvious effect on hypocotyl elongation. Gibberellic acid was found to reverse the inhibitory effect of CaCl2, causing an increase in growth rate similar to that found previously when GA3 was added to hypocotyls grown in H2O under non-flow-past conditions. We propose that gibberellin controls extension growth in lettuce hypocotyl sections by regulating the uptake of Ca2+ by the hypocotyl cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385362
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    The role of calcium ions in phytochrome-mediated germination of spores of Onoclea sensibilis L. (1984)
    Springer
    Planta 160 (1984), S. 12-20 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Calmodulin ; Germination (spore) ; Onoclea ; Phytochrome and Ca2+ ; Pteridophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome is confirmed to be the photoreceptor pigment in the germination response of Onoclea sensibilis L. by demonstrating red-far-red (R-FR) photoreversibility. External Ca2+ is required for this response with a threshold at a submicromolar concentration. Ethylene glycol-bis(β-amino-ethyl ether)-N,N,N′,N′-tetraacetic acid, La3+ and Co2+ reversibly inhibit germination. Lanthanum only inhibits germination when applied before or during irradiation, indicating that the external Ca2+ requirement is transient, although in the absence of Ca2+ the R-stimulated system remains maximally poised to accept the ion for over 4 h after irradiation. The ability to respond to Ca2+ 4.1 h after R-irradiation is not reversed by FR-irradiation, indicating that Ca2+ transport has been uncoupled from phytochrome. Barium and Sr2+, but not Mg2+ can substitute for Ca2+. Artificially increasing the concentration of intracellular free Ca2+ with the ionophore A 23187 stimulates germination in the dark. The Ca2+-calmodulin antagonists, trifluoperizine and chlorpromazine, reversibly inhibit germination. Calcium is required in phytochrome-mediated fern spore germination; it may be acting as a second messenger.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392460
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  • 100
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    Diurnal changes in the flux of calcium toward meristems and transpiring leaves in tomato and maize plants (1981)
    Springer
    Planta 151 (1981), S. 265-271 
    Details
    ISSN: 1432-2048
    Keywords: Calcium ; Cation exchange ; Lycopersicon esculentum ; Rhythm ; diurnal Transport (calcium) ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato (Lycopersicon esculentum Mill. cv. Moneymaker) and maize (Zea mays L. cv. spec.) plants were supplied with 45Ca-labeled nutrient solutions for a period of 8 or 16 h in the dark, in the light, or in a light-dark régime. Plant parts were analyzed for 45Ca content. The partitioning of 45Ca between mature leaves and meristems was shown to be affected by the presence of light. The transport of 45Ca to meristems was higher in a dark period than in a comparable light period. Experiments with excised tomato shoots yielded similar distribution patterns of 45Ca over leaves and meristems, thus excluding root pressure as the main driving force for the enhanced import of 45Ca into the meristems in the dark. Results are discussed in terms of cation-exchange transport and competition between the various calcium sinks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395179
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