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  • Ultrastructure  (212)
  • Drosophila  (111)
  • Springer  (322)
  • 1995-1999
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  • 1925-1929
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  • 1
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    Springer
    Biology and fertility of soils 9 (1990), S. 101-109 
    ISSN: 1432-0789
    Keywords: Phryganella acropodia ; Testate amoeba ; Growth rate ; Rhizopoda ; Feeding ; Fungal species ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Clones of Phryganella acropodia were cultivated under different trophic conditions with bacteria as the food source. The doubling time was estimated to be 3 days. The edibility of four species of fungi, Aspergillus niger, Cunninghamella echinulata, Penicillium echinulatum and Stilbella bulbicola, was tested, but only Penicillium enchinulatum and Stilbella bulbicola were eaten and digested by the amoeba. An ultrastructure examination showed that there are two contractile vacuoles, many dictyosomes, a single nucleus with several nucleoli, and peroxisomes. The pseudopodia are filiform when attached to the substrate but change to lobose when the animal is floating. A thin organic membrane covers the aperture of resting forms.
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  • 2
    ISSN: 1432-0827
    Keywords: Periodontal ligament fibroblast ; Mineralized nodule ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purposes of this study were to determine whether periodontal ligament (PDL) cells are capable of producing mineralized nodules in vitro and to analyze ultrastructural features of the nodules. Rat PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured at confluence in standard medium containing Dulbecco's Modified Eagle's Medium supplemented with 10% FBS and antibiotics. To test mineralized nodule formation, cells were further cultured for an additional 3 weeks in the standard medium containing (1) ascorbic acid (50 μg/ml) and sodium β-glycerophosphate (10 mM), (2) ascorbic acid, sodium β-glycerophosphate, and dexamethasone (5 μM), or (3) ascorbic acid alone. Cells were then fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4, and prepared for light and electron microscopy. Threedimensional nodules containing mineralized matrices were formed only when the cells were cultured in the presence of ascorbic acid and dexamethasone. They were composed of multilayered fibroblasts (up to 13 layers), and highly organized collagen fibrils with 64 nm cross-banding patterns between the cell layers. The fibroblasts in the nodules exhibited an elongated shape with a high degree of cytoplasmic polarity throughout the nodule, and have the morphological features of PDL fibroblasts as seen in vivo. Mineral deposition with needle-like crystals was initiated on collagen fibrils located in intercellular spaces of the upper cell layers and became increasingly heavier towards the bottom half of the nodules. X-ray microanalysis and electron diffraction analysis confirmed that mineral deposition contained calcium and phosphate in the form of immature hydroxyapatite. These nodules contained neither osteoblasts nor osteocytes, and have their own morphological organization and characteristics which differ from those formed by bone cells in culture. Therefore, these data suggest that PDL cells are capable of forming mineralized tissue in vitro with the morphological characteristics different from bone mineralized nodules.
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  • 3
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    Journal of molecular evolution 35 (1992), S. 51-59 
    ISSN: 1432-1432
    Keywords: Drosophila ; Gart locus ; Chironomus tentans ; Purine nucleotide biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Drosophila Gart locus consists of two genes. One gene encodes three enzymes in the de novo purine nucleotide biosynthesis pathway [glycinamide ribonucleotide synthetase (GARS), aminoimidazole ribonucleotide synthetase (AIRS), and glycinamide ribonucleotide transformylase (GART)]. The second gene lies within an intron of the purine gene and encodes a cuticle protein. To investigate the evolution of the Gart locus, the Chironomus tentans homolog was cloned by screening a genomic DNA library with a polymerase chain reaction product. This study shows that the interesting structural features of this locus conserved in two distant Drosophila species are not found in the Chironomus homolog. These features include the cuticle protein gene nested within an intron and the existence of an alternative transcript to yield a monofunctional enzyme. In addition, the extremely rapid divergence of coding sequence seen for members of the tandemly duplicated AIRS domain in Drosophila is found to be much less rapid in Chironomus.
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  • 4
    ISSN: 1432-1432
    Keywords: Drosophila ; per gene ; Threonine-Glycine ; repeat sequence ; melanogaster subgroup phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Threonine-Glycine (Thr-Gly) region of the period gene (per) in Drosophila was compared in the eight species of the D. melanogaster subgroup. This region can be divided into a diverged variable-length segment which is flanked by more conserved sequences. The number of amino acids encoded in the variable-length region ranges from 40 in D. teissieri to 69 in D. mauritiana. This is similar to the range found within natural populations of D. melanogaster. It was possible to derive a Thr-Gly “allele” of one species from that of another by invoking hypothetical Thr-Gly intermediates. A phylogeny based on the more conserved flanking sequences was produced. The results highlighted some of the problems which are encountered when highly polymorphic genes are used to infer phylogenies of closely related species.
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  • 5
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    Journal of molecular evolution 34 (1992), S. 130-140 
    ISSN: 1432-1432
    Keywords: Drosophila ; Sophophora ; cDNA-DNA hybridization ; Phylogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have performed DNA-DNA hybridization experiments among several species of Drosophila using the evolutionarily conserved portion of the genome representing sequences coding for amino acids of proteins. This was done by using as tracer, radioactively labeled complementary DNA that was reverse transcribed from adult mRNA. We show that this procedure extends phylogenetically the distance over which the technique can be applied to fast-evolving groups such as Drosophila. The major phylogenetic conclusions are (1) the subgenus Sophophora is a monophyletic lineage; (2) within Sophophora the melanogaster subgroup is closer to the obscura group than either group is to the willistoni group; (3) the subgenus Drosophila is complex with most major lineages originating deep in the phylogeny; the subgenus may not be monophyletic; (4) as with most groups classically placed in Drosophila, the Hawaiian Drosophila originate early, supporting the notion that this lineage is older than the extant islands; and (5) the virilis/repleta lineage is monophyletic within Drosophila.
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  • 6
    ISSN: 1432-1432
    Keywords: Histone H2A ; Histone variant ; Intron position ; Drosophila ; Tetrahymena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genomic clones ofDrosophila andTetrahymena histone H2A variants were isolated using the corresponding cDNA clones, (van Daal et al. 1988; White et al. 1988). The site corresponding to the initiation of transcription was defined by primer extension for bothDrosophila andTetrahymena genomic sequences. The sequences of the genomic clones revealed the presence of introns in each of the genes. TheDrosophila gene has three introns: one immediately following the initiation codon, one between amino acids 26 and 27 (gln and phe), and one between amino acids 64 and 65 (glu and val). TheTetrahymena gene has two introns, the positions of which are identical to the first two introns of theDrosophila gene. The chicken H2A.F variant gene has been recently sequenced and it contains four introns (Dalton et al. 1989). The first three of these are in the same positions as the introns in theDrosophila gene. The fourth intron interrupts amino acid 108 (gly). In all cases the sizes and the sequences of the introns are divergent. However, the fact that they are in conserved positions suggests that at least two of the introns were present in the ancestral gene. A phylogenetic tree constructed from the sequences of the variant and major cell cycle-regulated histone H2A proteins from several species indicates that the H2A variant proteins are evolutionarily separate and distinct from the major cell cycle-regulated histone H2A proteins. The ancestral H2A gene must have duplicated and diverged before fungi and ciliates diverged from the rest of the eukaryote lineage. In addition, it appears that the variant histone H2A proteins analyzed here are more conserved than the major histone H2A proteins.
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  • 7
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    Journal of molecular evolution 16 (1980), S. 37-46 
    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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  • 8
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    Journal of molecular evolution 30 (1990), S. 273-280 
    ISSN: 1432-1432
    Keywords: Genome evolution ; Molecular evolutionary rates ; Insect DNA ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNA-DNA hybridization studies of insects, more specificallyDrosophila and cave crickets, have revealed interesting patterns of genome evolution that contrast markedly with what has been seen in other taxa, especially mammals and birds. Insect genomes are composed of sections of single-copy DNA with extreme variation in rates of evolutionary change. This variation is more extreme than between introns and exons; introns fall into the relatively conserved fraction of the genome. Attempts to calculate absolute rates of change inDrosophila DNA have all led to estimates some 5–10 times faster than those found in most vertebrates; this is true even for the more conservative part of the nuclear genome. Finally we point out that morphological similarity, chromosomal similarity, and/or ability to form interspecific hybrids is often associated with quite high levels of single-copy DNA divergence in insects as compared to mammals and birds.
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  • 9
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    Development genes and evolution 188 (1980), S. 55-63 
    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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  • 10
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    Development genes and evolution 192 (1983), S. 42-44 
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
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  • 11
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    Development genes and evolution 192 (1983), S. 164-170 
    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.
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  • 12
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    Development genes and evolution 192 (1983), S. 275-279 
    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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  • 13
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    Development genes and evolution 192 (1983), S. 299-302 
    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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  • 14
    ISSN: 1432-041X
    Keywords: Compound eye morphogenesis ; Enhancer of split ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spl mutation of the N gene causes, among other phenotypic traits, the lack of a few ommatidia, roughness and a general reduction in the size of the compound eye; these defects are drastically enhanced by the dominant mutation E(spl) D. We have studied cellular and developmental aspects of the phenotypic interaction between spl and E(spl) D. We found that the initial clustering of photoreceptor cells is affected in eye imaginal discs of spl larvae causing the defects visible in the adult eye. The degree of disorganization of the spl/Y; E(spl) D/ + eye disc is much higher, only a few photoreceptor cells are able to group with representatives of the other cell types and differentiate normally. BrdU incorporation shows that the proliferation pattern of the spl/Y; E(spl) D/ + disc cells during the third instar is normal. Abundant cell death occurs posteriorly in the mutant discs, which accounts for their small size. Finally, we found that in the eye imaginal disc the transcription of m8, the E(spl) gene, responsible for the enhancement of the spl phenotype caused by the E(spl) D mutation, is restricted to the morphogenetic furrow, where the ommatidial cells start grouping with each other to take on their future developmental fates; the m8 transcription rate is highly increased in E(spl) D eye discs. All these observations indicate that the assembly of the ommatidial cells is affected in the spl/Y; E(spl) D/ + disc and that the other abnormalities are morphogenetic consequences of the defective cell grouping.
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  • 15
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    Development genes and evolution 198 (1990), S. 474-478 
    ISSN: 1432-041X
    Keywords: Arginine kinase ; Imaginal discs ; 20-hydroxyecdysone ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Arginine kinase (AK) is present throughout the life cycle of Drosophila melanogaster, but there is a sharp, transient peak of AK activity during the prepupal period and a second period of elevated activity at the time of eclosion of the adult. Imaginal discs show the greatest increase in AK activity at the prepupal stage of those tissues assayed. The prepupal peak is not seen when the temperature-sensitive ecdysoneless mutant ecd-1 is shifted to 29° C at mid-third instar larval stage. The peak in activity reappears when ecd-1 is either shifted back to 20° C after 60 h at 29° C or is fed 20-hydroxyecdysone. At the restrictive temperature, imaginal discs from ecd-1 larvae progressively lose AK activity, whereas discs from 20-hydroxyecdysone-fed larvae have a marked increase in AK activity at stage P3 of the prepupal period. These data suggest that the prepupal peak is regulated by the hormone 20-hydroxyecdysone.
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  • 16
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    Development genes and evolution 198 (1990), S. 479-482 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Cell culture, wing ; In vitro
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have devised a protocol for the cloning of our cell lines, and have demonstrated that a cloned line may contain cells of widely differing morphology — epithelial, fibroblast-like, and lamellocyte-like. These different morphologies must therefore represent diversity in the microenvironment of the culture rather than diversity in the cellular origin of the line.
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  • 17
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    Development genes and evolution 199 (1990), S. 31-47 
    ISSN: 1432-041X
    Keywords: Bristle ; Pattern formation ; Drosophila ; Gamma rays ; Mitomycin C ; Heat shock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of a leg segment of the fruitflyDrosophila melanogaster was analyzed in order to determine whether the orderliness of the segment's bristle pattern originates via waves of cellular interactions, such as those that organize the retina. Fly development was perturbed at specific times by either teratogenic agents (gamma rays, heat shock, or the drug mitomycin C) or temperature-sensitive mutations (l(1)63, l(1) Notchts1, orl(1) shibire ts1 ), and the resulting abnormalities (e.g., missing or extra structures) were mapped within the pattern area. If bristles develop in a linear sequence across the pattern, then they should show sensitivity to perturbations in the same order, and wavefronts of cuticular defects should result. Contrary to this prediction, the maps reveal no evidence for any directional waves of sensitivity. Nevertheless, other clues were uncovered as to the nature and timing of patterning events. Chemosensory bristles show earlier sensitivities than mechanosensory bristles, and longer bristles precede shorter ones. The types and sequence of cuticular abnormalities imply the following stages of bristle pattern development: (1) scattered inception of bristle mother cells, each surrounded by an inhibitory field, (2) alignment of the mother cells into rows, (3) differential mitoses, (4) assignment of cuticular fates to the mitotic progeny, (5) polytenization of the bristle cells, (6) fine-tuning adjustments in bristle spacing, and (7) signalling from bristle cells to adjacent epidermal cells, inducing them to form “bracts”.
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  • 18
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    Development genes and evolution 199 (1990), S. 48-62 
    ISSN: 1432-041X
    Keywords: Bristle ; Sensilla ; Pattern formation ; Drosophila ; achaete-scute complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The arrangement of bristles on a leg segment of the fruitflyDrosophila melanogaster was studied in various mutants that have abnormal numbers of bristles on this segment. Eighteen mutations at six different genetic loci were analyzed, plus five double or triple mutant combinations. Recessive mutations at theachaete-scute locus were found to affect distinct groups of bristles:achaete mutations remove mechanosensory bristles, whereasscute mutations remove mainly chemosensory bristles. Mechanosensory bristles remain uniformly spaced along the longitudinal axis unless their number decreases below a certain threshold, suggesting that spacing is controlled by cell interactions that cannot function when bristle cells are too far apart. Above a certain threshold, bristle spacing and alignment both become irregular, perhaps due to excessive force from these same interactions. Chemosensory bristles occupy definite positions that are virtually unaffected by removal of individual bristles from the array. Extra chemosensory bristles develop only near the six normal sites. At two of the six sites the multiple bristles tend to exhibit uniform longitudinal spacing — a property confined to mechanosensory bristles in wild-type flies. To explain the various mutant phenotypes the following scheme is proposed, with different mutations directly or indirectly affecting each step: (1) spots and stripes are demarcated within the pattern area, (2) one bristle cell normally arises within each spot, multiple bristle cells within each stripe, (3) incipient bristle cells inhibit neighboring cells from becoming bristle cells, and (4) the bristle cells within each stripe become aligned to form rows and then repel one another to generate uniform spacing.
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  • 19
    ISSN: 1420-9071
    Keywords: Aromatic plants ; essential oils ; Drosophila ; insecticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Effects of the essential oils (EOs) extracted from eleven aromatic plants belonging to the Lamiaceae family (common in the Greek flora) were examined upon three different developmental stages ofDrosophila auraria. All of the EOs examined exhibited insecticidal effects, either by preventing egg hatching, or by causing the death of larvae and adult flies. In several cases, malformation and/or prohibition of puparium formation was also observed.
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  • 20
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    Development genes and evolution 192 (1983), S. 171-178 
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
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  • 21
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    Development genes and evolution 192 (1983), S. 280-284 
    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.
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  • 22
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    Development genes and evolution 192 (1983), S. 337-346 
    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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  • 23
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    Development genes and evolution 188 (1980), S. 65-73 
    ISSN: 1432-041X
    Keywords: Nuclear migration ; Cleavage ; Microtubules ; Ultrastructure ; Gall midge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the eggs ofWachtliella persicariae the cleavage nuclei move relative to the surrounding ooplasm. This ‘active’ migration is caused by an organelle whose ultrastructure was studied throughout the mitotic cycle. It consists of a greatly enlarged polar cytaster derived from the mitotic apparatus, linked to the nucleus by 100 Å filaments. The microtubules of the cytaster were found only during periods of active nuclear migration, i.e., from the onset of anaphase to the early prophase of the next mitotic cycle. They are always solitary and follow the course of the astral rays, which are known to temporarily adhere to peripheral structures of the egg cell and to exert tractive forces. In contrast to the cytaster microtubules, the microtubules in the spindle are bundled and persist from early metaphase through late telophase. During ontogenesis the first migration cytaster is built up between 3 and 12 min after oviposition near the anterior egg pole, in the vicinity of the sperm nucleus. In non-inseminated eggs time lapse films show a migration cytaster to develop autonomously in a region free from nuclei, but it does not follow the normal path of the male pronucleus. In several cases the female pronucleus, which remains without a cytaster of its own, was observed to move to the cytaster generated in the absence of the male pronucleus. Whether or not it is adhering to a nucleus, the cytaster divides into two at the correct time, i.e, corresponding to the first cleavage division in fertilized eggs. In some non-inseminated eggs this type of ‘pseudocleavage’ has been observed to occur repeatedly, giving rise to an increasing number of anucleate cytasters.
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    Development genes and evolution 198 (1990), S. 411-419 
    ISSN: 1432-041X
    Keywords: Drosophila ; Embryonic cells ; Ca2+-dependent cell aggregation ; Inhibiting antibodies ; Aggregation proteins
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    Notes: Summary By using an in vitro functional assay, we have shown that Drosophila embryonic cells possess Ca2+-dependent adhesive sites, which resemble in many respects those described for vertebrate cells and tissues. The cells, obtained by mechanical disruption of gastrulastage embryos, form aggregates within 30 min when maintained under constant rolling. The aggregation is completely dependent on the presence of Ca2+ in the medium. In its absence, the cells remain dispersed but the process is reversible by readdition of Ca2+. In addition the aggregation is temperature-dependent. No aggregation occurs at 4° C but it can be restored by raising the temperature to 25° C. These properties are characteristic of these cells: established cell lines do not aggregate under the same conditions and mixing of cell lines and embryonic cells does not result in chimeric aggregates, thus pointing towards cell-type selectivity with respect to aggregability. Observations in electron microscopy have shown that the embryonic cells in the aggregates tightly adhere to one another and form, as early as after 30 min, maculae adherens junctions. Drosophila embryonic cells have adhesion sites that are protected from trypsin proteolysis in the presence of Ca2+ and sensitive in its absence. The cells' aggregation can be inhibited by a mouse antiserum directed against cell-surface components and a good correlation exists between neutralization of the inhibitory activity of the antiserum and the presence of trypsin-sensitive sites on the cells. These data are in favour of cell-cell adhesion mediated by specific adhesion proteins.
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  • 25
    ISSN: 1432-041X
    Keywords: Crumbs ; Drosophila ; Epithelial development ; Cell death ; Cell polarity ; Non autonomous behaviour
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    Notes: Summary The genecrumbs (crb) ofDrosophila melanogaster provides an essential function for the embryonic development of ectodermally derived epithelia. Complete loss of function alleles of thecrb gene are recessive embryonic lethals and lead to a disorganization of the primordia of these epithelia, followed by cell death in some tissues. Incrb mutant embryos, different organs are affected to a different extent. Some tissues die almost completely (as the epidermis, the atrium and the pharynx) while others partially survive and conserve their basic epithelial structure (as the tracheal system, the oesophagus, the proventriculus, the salivary glands, the hindgut and the Malpighian tubules). Degeneration is first visible at stage 11 and continues successively throughout development. There is evidence that the loss of epithelial cell polarity may be the cause for the degeneration of these tissues, suggesting that thecrb gene product is involved in stabilizing the apico-basal polarity of epithelial cells. As previously shown, thecrb protein is specifically expressed on the apical side of embryonic epithelia in a reticular pattern outlining the borders of the cells. Here we demonstrate that thecrb protein shows the same subcellular localization in epithelial cells of imaginal discs and in follicle cells, indicating a similar function ofcrb during the development of embryonic, imaginal and follicle epithelia. Clonal analysis experiments indicate that the genecrb is not cell-autonomous in its expression, suggesting that the gene product may act as a diffusible factor and may serve as a signal in a cell-cell communication process. This signal is thought to be required for the formation and/or maintenance of the cell and tissue structure of the respective epithelia.
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  • 26
    ISSN: 1432-041X
    Keywords: Muscle ; Salivary glands ; Gut ; Programmed cell death ; Steroid hormones ; Drosophila
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    Notes: Summary In holometabolous insects, the steroid molting hormone 20-OH-ecdysone (ecdysterone) orchestrates the diverse developmental events of metamorphosis, in large part by regulating gene expression. In Drosophila, the Broad Complex (BR-C) is one of the first loci to be induced by ecdysterone at the end of larval life, and is essential for translating the hormonal signal into the behavioral and anatomical events which herald the onset of metamorphosis. BR-C products are believed to act by binding to and modifying the transcriptional activities of other hormone-sensitive genes. In addition to abnormalities of the epidermis, BR-C mutants dying during metamorphosis manifest a syndrome of multiple internal tissue defects which represent a failure of the larval-to-adult transition. We have reported features of central nervous system metamorphosis requiring BR-C function, notably morphogenetic movements and optic lobe organization. In this paper we describe defective development of salivary glands, flight muscles, and gut in BR-C mutants, including: persistence of larval salivary glands; failure of the adult salivary glands to extend into the thorax; abnormalities of midgut transition and of proventriculus structure and location; and absence of dorsal-ventral indirect flight muscles. Some of these abnormalities represent defects in programmed cell death. Distinct patterns of phenotypes were seen in mutants of each of the three lethal complementation groups comprising the BR-C. The patterns of phenotypes suggest overlapping but distinct functions encoded by this complex locus.
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  • 27
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Pattern formation ; rotund
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    Notes: Summary InDrosophila imaginal discs, pattern formation requires the activity of three positional information systems, antero-posterior (A/P), dorso-ventral (D/V) and proximo-distal (P/D). Three genes,Decapentaplegic, Distal-less androtund (rn), involved in pattern formation along the P/D axis have been characterized. Thern gene is required in a sub-distal region, localized at a similar position along the P/D axis in all appendages; it encodes two major transcripts, m1.7 and m5.3, both expressed in the central region of all the major imaginal discs. The present study of these transcripts in severalrn mutant favours m5.3 as encodingrn morphogenetic function in the imaginal discs. The fine characterization of its distribution partitions all major imaginal discs in domains along the P/D axis. The ventral and dorsal discs appear to be similarly but not identically organized: two P/D domains are evident in the wing and haltere discs whilst the leg and antenna discs appear to be composed of at least three. We also show that m5.3 is sex-regulated in the genital disc and thatrn function is required for proper development of a sub-distal structure of the female genitalia. This suggests that the primordia of the female genitalia may be organized in a similar way to the other imaginal discs, and strongly supports the hypothesis thatrn function is specific to pattern formation along the P/D axis and that it may be involved in the establishment or maintenance of this pattern.
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  • 28
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    Development genes and evolution 201 (1992), S. 364-375 
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    Keywords: Drosophila ; Tissue culture ; In vitro ; Invertebrate embryogenesis
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    Notes: Summary We have devised techniques to culture whole, dissected embryos of Drosophila melanogaster. We examine multiple aspects of the morphological and physiological development of the epidermis, musculature, nervous system, and internal organs in this cultured preparation, and show that in vitro development closely parallels normal embryogenesis. These techniques permit a wide range of experimental manipulations during embryogenesis and allow us to extend observations through late embryonic stages, after cuticle deposition. Applications of this technique are presented.
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  • 29
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    Development genes and evolution 188 (1980), S. 163-177 
    ISSN: 1432-041X
    Keywords: Yolk sac ; Ultrastructure ; Embryogenesis ; Drosophila
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    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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  • 30
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    Development genes and evolution 189 (1980), S. 57-67 
    ISSN: 1432-041X
    Keywords: Drosophila ; Ecdysone deficient mutants ; Ecdysteroid titer ; Ring gland ; Fine structure
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    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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    Development genes and evolution 188 (1980), S. 157-161 
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    Keywords: Drosophila ; Imaginal discs ; Compartments ; Distal outgrowth
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    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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  • 32
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    Development genes and evolution 189 (1980), S. 91-96 
    ISSN: 1432-041X
    Keywords: Epimorphic regulation ; Drosophila ; Imaginal discs
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    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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  • 33
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    Development genes and evolution 192 (1983), S. 48-50 
    ISSN: 1432-041X
    Keywords: Drosophila ; Hybrid lethality ; Imaginal discs ; Interspecific transplantation
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    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
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  • 34
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    Development genes and evolution 192 (1983), S. 270-274 
    ISSN: 1432-041X
    Keywords: Fate map ; Repressed primordium ; Sex determination ; Genital disc ; Drosophila
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    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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  • 35
    ISSN: 1432-041X
    Keywords: Drosophila ; Cell degeneration ; Imaginal disc ; Basal lamina ; Blood cells
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    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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  • 36
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    Development genes and evolution 192 (1983), S. 317-326 
    ISSN: 1432-041X
    Keywords: Neurogenic mutations ; Topological specificity ; Drosophila
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    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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  • 37
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    Development genes and evolution 198 (1990), S. 295-302 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Embryogenesis ; Ecdysteroids ; Localized factors
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    Notes: Summary We have produced monoclonal and polyclonal antibodies against an antigen that is asymmetrically distributed in mature oocytes of Drosophila melanogaster. During late oogenesis and early embryogenesis the antigen undergoes dramatic changes in its cellular localization: until about 2.5 h before completion of oogenesis it is homogeneously distributed in the cytoplasm, then it becomes localized in granules that are more numerous in posterior than in anterior peripheral positions of the ooplasm. The germ plasm is void of the antigen. Shortly after egg deposition the antigen is released from the granules and forms a shallow temporary gradient in the egg. Later during embryogenesis the antigen is associated with the yolk-containing cytoplasm. At the syncytial blastoderm stage it is also detected in the peripheral nuclei. Preliminary evidence suggests that the antigen is an ecdysteroid-related molecule. Five different anti-ecdysone antisera were found to bind to the same antigen or to an antigen with the same localization as our monoclonal antibody. In pattern mutants affecting anteroposterior polarity, the described asymmetrical distribution of the antigen is abnormal. In the mutant BicD, for example, which leads to the formation of two abdomina of opposite polarity, the antigen-containing granules are distributed homogeneously in mature oocytes.
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  • 38
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    Development genes and evolution 198 (1990), S. 402-410 
    ISSN: 1432-041X
    Keywords: Anteroposterior polarity ; Cytoplasmic factors ; Drosophila ; Cytoplasm transplant ; Maternal-effect mutants
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    Notes: Summary Cytoplasm removal/transplant techniques applied to Drosophila cleavage-stage embryos induced changes in anteroposterior polarity. Removal of anterior cytoplasm or anterior transplantation of posterior cytoplasm caused the anterior formation of posterior (telson) structures, and the replacement of anterior cytoplasm with posterior cytoplasm induced double-abdomen embryos, as reported by Frohnhöfer et al. [J Embryol Exp Morphol 97 (suppl):169–179 (1986)]. Changing the conditions of anterior cytoplasm removal we showed that greater volumes, earlier stages, and removal from the periphery were efficient. In addition we found that double-cephalon embryos are induced by replacing posterior cytoplasm with anterior cytoplasm, while removal of posterior cytoplasm or the posterior transplantation of anterior cytoplasm was without effect. However, introduction of anterior cytoplasm into the posterior of nanos embryos, which are mutants not developing abdominal segments, caused the formation of double-cephalon embryos. Similarly, double-abdomen embryos are produced by introducing posterior cytoplasm into the anterior of bicoid embryos, which are mutants not forming cephalic and thoracic structures. These results are compatible with the initial involvement of separate anterior, posterior and terminal cytoplasmic factors deduced from mutant analysis (Nüsslein-Volhard and Roth 1989).
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  • 39
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    Development genes and evolution 198 (1990), S. 275-285 
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Notch ; split ; daughterless ; Genetic interactions ; Second-site modifiers ; Drosophila
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    Notes: Summary We have searched for dominant modifiers, i.e., enhancers and suppressors, of the compound eye phenotype of split, a recessive viable allele of Notch. Among the spl modifiers found, we have detected mutations in loci whose functions were previously known to cooperate with Notch in embryonic neurogenesis, such as daughterless, master mind, Delta and Hairless. In addition, other spl modifier mutations have been found in loci that were not previously known to interact with Notch, such as scabrous, glass, roughened eye, and several other genes that have not yet been assigned to known loci. The phenotypes associated with mutations in some of these latter loci suggest the participation of the corresponding genes in embryonic neurogenesis. We show that in some cases the observed interactions are due to genetic haplo-insufficent expression of the genes, whereas allele-specific interactions with spl are observed in master mind and Delta alleles. From this observation, we propose a direct functional association between the proteins encoded by Notch, Delta and master mind.
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  • 40
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    Development genes and evolution 201 (1992), S. 105-112 
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    Keywords: Drosophila ; Genital disc ; tra-2 ts ; Differentiation
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    Notes: Summary Diplo-X flies homozygous for the transform-er-2 ts (tra-2 ts) mutation develop into females at 16° C, while they develop into males at 29° C (Belote and Baker 1982). By means of this conditional mutation, we have carried out a detailed analysis of the development of the genital disc. Temperature shifts between 16 and 29° C, in both directions, and temperature pulses at 29° C, have been applied during the larval growth of tra-2 ts homozygous diplo-X flies, and the external derivatives of the genital disc have been analysed. Genital discs shifted from 16 to 29° C rapidly lose their capacity to differentiate female genital structures, while they become able to differentiate male genital structures whose inventory is more complete the earlier in larval development the temperature shift is carried out; moreover, duplicated male genital structures were observed. In the shift from 29 to 16° C, the genital disc loses its capacity to differentiate male genital structures, while it becomes able to differentiate female genital structures. The inventory of male structures is smaller, and the inventory of the female structures is more complete, the earlier in larval development the temperature is shifted. No duplicated female or male genital structures were observed in the downshift experiment. With respect to the analia, the shift from 16 to 29° C resulted in the quick formation of pure male anal plates, while in the opposite shift the formation of pure female anal plates occurred gradually. Moreover, the time course for the dorsal and ventral anal plates to show normal female phenotype was different: when the dorsal anal plates were completely normal, it was still possible to find incomplete ventral anal plates. In the pulse experiment at 29° C, the genital disc is able to differentiate both female and male genital structures, although the inventory of the latter ones was not complete. In addition, the capacity of the genital disc to differentiate male genital structures depended on the duration of the temperature pulse. The anal plates were always female, although they showed a reduction in their size, the ventral female anal plate being more affected than the dorsal one. No male anal plates were observed. The results have revealed that the genital disc follows a sequence in its capacity to differentiate female or male adult structures. We suggest that this sequence reflects the sequence of determination events occurring in the genital disc during its larval growth. In addition, results shown here provide evidence for the existence in the female genital primordium of a set of cells capable of giving rise either to female genital structures (ventral vaginal plates) or to male genital structures (hypandrium and penis apparatus). We also present evidence supporting the previous idea of two primordia for the anal plates.
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  • 41
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    Keywords: Drosophila ; Homeotic gene regulation ; Antennapedia ; Development ; β-galactosidase
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    Notes: Summary In order to study the regulation of spatial and temporal expression of the homeotic gene Antennapedia (Antp) in Drosophila melanogaster, we have constructed fusion genes which contain Antp sequences linked to the reporter gene lac Z of Escherichia coli. In one case of P-element transformation, a fusion gene construct integrated into the endogenous Antp gene close to one of the two promoters (P1). The spatial expression from the reporter gene in this transformant line, as analysed by the detection of β-galactosidase activity, was found to exactly mimic the normal expression from the P1 promoter of the Antp gene. We have used this unique transformant as a tool for studying the expression of the P1 promoter in embryonic, larval and adult development. Parallel lines transformed with the same fusion gene construct did not confer a correct P1 pattern of expression. The position in the genome was, therefore, crucial for the expression pattern of the reporter gene. Experiments aiming at the detection of autoregulatory control of Antp gene expression were designed. The results did not, however, support models of positive or negative autoregulation of P1 expression by Amp protein.
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    Development genes and evolution 201 (1992), S. 120-123 
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    Keywords: Integrin ; Drosophila ; In vitro ; Imaginal disc
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    Notes: Summary Drosophila imaginal disc cell lines show a characteristic pattern of aggregation in culture, which appears to be due to cell-cell rather than cell-substrate interactions. We have examined the distribution of PS integrins in wing and leg cell lines, and find that these integrin homologues are expressed preferentially in aggregates. Cell sheets, small cell clumps and chains of cells express antigen at points of cell-cell contact only.
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  • 43
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    Keywords: Drosophila ; Pattern formation ; Segment polarity genes ; gooseberry ; Cell interactions
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    Notes: Summary Segment polarity genes define the cell states that are required for proper organization of each metameric unit of the Drosophila embryo. Among these, the gooseberry locus has been shown to be composed of two closely related genes which are expressed in an overlapping single-segment periodicity. We have used specific antibodies raised against the protein product of the gooseberry proximal (gsb-p) gene to determine the spatial distribution of this antigen in wild type embryos, and to monitor the effects of segment polarity mutants on the pattern of the gsb-p protein distribution. We find that the gsb-p protein accumulates beneath each posterior axonal commissure in the progeny of neuroblasts deriving from the epidermal compartments of wingless (wg) and engrailed (en) expression. The results of this analysis support the idea that gsb-p has a specific role in the control of cell fates during neurogenesis, and indicate that en and wg provide critical positional cues to define the domain in which gsbp will be activated. Furthermore, these data suggest that, in order to be expressed in the embryonic CNS, gsb-p may preliminarily require activity of the gooseberry-distal gene in the epidermis.
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    Development genes and evolution 201 (1992), S. 88-94 
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    Keywords: Fate map ; Drosophila ; Flight muscle ; Mosaics ; Cell lineage
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    Notes: Summary A blastoderm fate map has been prepared for Drosophila, using mosaics of a temperature-sensitive mutation, shibire (shi). The mutation can cause abnormal flight muscle morphology, inducible only by a short heat pulse in early metamorphosis. Thus muscle lineage and development are unperturbed until the heat pulse in the early pupa. The developmental focus of the shi muscle phenotype maps to the ventral thorax at the expected site of thoracic mesoderm, and probably indicates the blastoderm progenitors of the adult flight muscle. The fate map provides greater detail than previously available for the dorsolongitudinal fibers (DLM) of flight muscle, showing wide separation of the fibers of flight muscle. DLM fibers a and b map close together, and far anterior to fibers e and f, which also map together. On a fate map, common developmental focus indicates a common blastoderm origin. Thus, the observed pattern for DLM fibers suggests that the blastoderm progenitors for each of these syncytial fiber pairs (a, b; e, f) include only one or two cells. It follows that there is usually a single genotype within each fiber pair (a, b; e, f), and that this genotype is directly reflected in the fiber phenotype. In a large number of cases, DLM fibers a and b differ in phenotype from other DLM fibers, in parallel with their other differences (e.g., timing of development in pupa, innervation, motor activity). The separation of fate map locations of the developmental focus for DLM fibers within mesoderm suggests that specific fibers of flight muscle may, in normal development, originate in all three thoracic mesodermal parasegments.
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    Development genes and evolution 202 (1992), S. 23-35 
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    Keywords: Ecdysteroid ; Imaginal disc ; Drosophila ; Cell line
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    Notes: Summary We have investigated the action of the moulting hormone 20-hydroxy ecdysone (20-HOE) on our leg and wing imaginal disc cell lines. At the morphological level, cells stop dividing and there is some cell death. The remaining cells elongate and aggregate, often producing long processes which form connections between different aggregates. 20-HOE acts within the first one or two days of a passage, at an optimum concentration of 10 ng/ml, this being about 1/100 of the optimum for ecdysone. One cloned wing cell line, C9, has been found to be relatively insensitive to the action of 20-HOE. We have been able to select for resistance to 20-HOE by growing cells in gradually increasing concentrations of hormone followed by passages in hormone-free medium. This has enabled us to isolate a wing cell line C1.8R from its parent cloned line C1.8+. This shows no response to 20-HOE, and cell growth continues even at hormone concentrations as high as 150 ng/ml. We have measured chitin synthesis by the incorporation of radioactive glucosamine into a cell fraction resistant to extensive alkali hydrolysis. The residue was incubated with chitinase, which resulted in a 50% reduction in labelled product. Treatment with 10 ng/ml of 20-HOE dramatically increased chitin synthesis in line C1.8+, but had no effect in the line C1.8R, selected for resistance to hormone.
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  • 46
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    Development genes and evolution 202 (1992), S. 49-60 
    ISSN: 1432-041X
    Keywords: Drosophila ; Delta ; Enhancers ; Suppressors ; Neurogenesis
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    Topics: Biology
    Notes: Summary We have screened for dominant enhancers and suppressors of the wing phenotype associated with two Delta alleles: Dl 9P39, an amorphic allele, and Dl FE32, an antimorphic allele. The interactions of some of the modifiers with Delta are due to haplo-insufficient expression of the corresponding genes. Although not explicitly shown for the remaining cases, we assume that haploin-sufficiency is also the basis for the relationships of these genes to Delta, since no allele specific interactions were observed. The modifiers found define 22 genes with pleiotropic expression, which can be classified into two groups: genes required for wing vein pattern formation and for neurogenesis, and genes which are not required for neurogenesis. Among the genes of the first group, Hairless and Star were previously known to participate in neural development. One further modifier was found which may correspond to a new neurogenic gene. The second group of genes is larger and includes already known loci, e.g., Plexate, blistered, plexus, etc, as well as other previously unidentified genes, which function during wing morphogenesis.
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  • 47
    ISSN: 1432-041X
    Keywords: Determination ; Germ-line ; Somatic cells ; Inhibitor gradient hypothesis ; Drosophila
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    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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  • 48
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    Development genes and evolution 189 (1980), S. 1-15 
    ISSN: 1432-041X
    Keywords: Cell line ; Drosophila ; Ecdysone ; Ecdysterone ; Hormones
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    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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  • 49
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    Keywords: Eggshell ; Chorion ; Peroxidase ; Crosslinking ; Drosophila
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    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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  • 50
    ISSN: 1432-041X
    Keywords: Early neurogenesis ; Neurogenic mutants ; Drosophila
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    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.
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  • 51
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    Development genes and evolution 188 (1980), S. 153-156 
    ISSN: 1432-041X
    Keywords: Drosophila ; Embryogenesis ; mat (3) 1 mutation ; Two-dimensional gels
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    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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  • 52
    ISSN: 1432-041X
    Keywords: Drosophila ; Geographic strains ; Chorion proteins ; Electrophoretic variants ; Chorion gene linkage
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    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.
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  • 53
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    Development genes and evolution 189 (1980), S. 147-153 
    ISSN: 1432-041X
    Keywords: Homeotic mutant ; Drosophila ; Clonal analysis ; Timing of gene action ; Determination
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    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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  • 54
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    Development genes and evolution 201 (1992), S. 1-11 
    ISSN: 1432-041X
    Keywords: Drosophila ; Neurogenesis ; Signals ; Delta ; Notch
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    Topics: Biology
    Notes: Summary The ectodermal germ layer of Drosophila melanogaster gives rise to two major cell lineages, the neural and the epidermal. Progenitor cells for each of these lineages arise from groups of cells, whose elements must decide between taking on either fate. Commitment of the progenitor cells to one of the developmental fates implies two factors. One is intrinsic to the ectodermal cells and determines a propensity to take on neural fate; this factor is probably represented by the products of the so-called proneural genes, which are differentially distributed throughout the ectoderm. The other factor in the cells' decision to adopt one of the two alternative fates is intercellular communication, which is mediated by the products of the so-called neurogenic genes. Two types of interactions, one inhibiting and the other stimulating neural development, have been inferred. We discuss here the assumed role of various neurogenic genes, in particular Notch and Delta, in these processes.
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  • 55
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    Development genes and evolution 201 (1992), S. 194-220 
    ISSN: 1432-041X
    Keywords: Drosophila ; Enhancer trap lines ; Embryogenesis
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    Topics: Biology
    Notes: Summary Embryos of 171 Drosophila lines carrying a P-lacZ insertion on the second or third chromosome were analyzed regarding their pattern of lacZ expression. All lines were selected from a larger screen of about 4000 lines (Bier et al. 1989). Tissue specificity and time of onset of lacZ expression was documented for each line. Thereby, a comprehensive list of markers for the various tissue and cell types of the Drosophila embryo could be assembled. With the help of several P-lacZ lines the development of a number of structures was studied which so far had been described only insufficiently or not at all. In particular, the embryonic origin and early development of the oenocytes, imaginal discs, histoblasts, fat body, dorsal vessel, and perineurial cells was analyzed. Several previously unknown cell types associated with the dorsal vessel, trachea, and epidermis were discovered. By combining data regarding the origin of the different mesodermally derived organs it was possible to generate in some detail a fate map of the mesoderm of the stage 11 Drosophila embryo.
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  • 56
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    Cellular and molecular life sciences 48 (1992), S. 623-629 
    ISSN: 1420-9071
    Keywords: Drosophila ; heat shock ; stress ; heat shock protein ; gene regulation
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    Topics: Biology , Medicine
    Notes: Abstract Major alterations in genetic activity have been observed in every organism after exposure to abnormally high temperatures. This phenomenon, called the heat shock response, was discovered in the fruit flyDrosophila. Studies with this organism led to the discovery of the heat shock proteins, whose genes were among the first eukaryotic genes to be cloned. Several of the most important aspects of the regulation of the heat shock response and of the functions of the heat shock proteins have been unraveled inDrosophila.
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  • 57
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    Calcified tissue international 31 (1980), S. 93-108 
    ISSN: 1432-0827
    Keywords: Calculus ; Ultrastructure ; Apatite ; Transmission ; Scanning
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    Topics: Biology , Medicine , Physics
    Notes: Summary Using transmission and scanning electron microscopy, we have studied the ultrastructure of a number of urinary calculi, mainly composed of calcium phosphate. Three fundamental kinds of calcium phosphates were detected: nonstoichiometric carbonate apatite, nonhexagonal octacalcium phosphate, and calcium-magnesium whitlockite. The influence that the organic matter, substitutions in the phosphate lattice of CO3 and Mg, and apatitic stoichiometry have on the ultrastructure of the calcium phosphate calculi has been detailed. An originating apatitic unity named U2 is assumed to be the responsible for all the different structures of calcium apatites appearing in renal calculi. On the basis of our observations, a mechanism whereby apatites grow is postulated; magnesium functions as an inhibitor for the growing mechanism.
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    Calcified tissue international 30 (1980), S. 27-34 
    ISSN: 1432-0827
    Keywords: Ultrastructure ; Calcium ; Cartilage ; Vesicles
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    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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  • 59
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    Planta 188 (1992), S. 403-413 
    ISSN: 1432-2048
    Keywords: Cyanobacterium ; Gunnera ; Infection process ; Nostoc ; Symbiosis ; Ultrastructure
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    Topics: Biology
    Notes: Abstract The symbiosis between Gunnera and Nostoc was reconstituted using G. chilensis Lam. and G. manicata Linden, respectively, and three different Nostoc strains. Six stages characterised by specific modifications in both the cyanobiont and the host were recognised during the infection process. Mucilage-secreting stem glands developed on the Gunnera stems independent of the presence of cyanobacteria (Stage I). Soon after addition of the Nostoc isolates to the plant apices, an abundant differentiation of motile hormogonia commenced. The cyanobacteria accumulated in the mucilage on the surface of the gland (Stage II), and the hormogonia then proceeded into the stem tissue through intercellular channels (Stage III). At the channel bases, Nostoc was detected between the cell walls of small, densely cytoplasmic Gunnera cells and also in elaborate folds of these (Stage IV). The Gunnera cell walls subsequently dissolved adjacent to the cyanobacteria and Nostoc entered the host cells (Stage V). Once the intracellular association was formed, a high proportion of the vegetative Nostoc cells differentiated into heterocysts (Stage VI). Nostoc changed from being rich in inclusions (particularly cyanophycin) while on the gland surface into a comparatively “non-storing” form during penetration and the early intracellular stages. Bacteria were numerous on the gland surface, fewer in the channels, and were never detected within the Gunnera cells, indicating the existence of specific recognition mechanisms discriminating between conceivable microsymbionts. Mechanisms behind mutual adaptations and interactions between the two symbionts are discussed.
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  • 60
    ISSN: 1432-2048
    Keywords: Bradyrhizobium ; Electron microscopy ; Glycine (root nodules) ; High-pressure freezing ; Ultrastructure
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    Topics: Biology
    Notes: Abstract High-pressure freezing of chemically untreated nodules of soybean (Glycine max (L.) Merr.), in sharp contrast to chemical fixation and prefixation, appears to preserve the ultrastructure close to the native state. This is supported by the observation that the peribacteroid membrane of high-pressure-frozen samples is tightly wrapped around the bacteroids, a finding that is fully consistent with the current views on the physiology of oxygen and metabolite transport between plant cytosol and bacteroids. In soybean root nodules, the plant tissue and the enclosed bacteria are so dissimilar that conventional aldehyde-fixation procedures are unable to preserve the overall native ultrastructure. This was demonstrated by high-pressure freezing of nodules that had been pre-fixed in glutaraldehyde at various buffer molalities: no buffer strength tested preserved all ultrastructural aspects that could be seen after high-pressure freezing of chemically untreated nodules.
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    Oecologia 92 (1992), S. 183-187 
    ISSN: 1432-1939
    Keywords: Drosophila ; Resource exploitation ; Decaying-herbage breeding ; Host choice
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    Topics: Biology
    Notes: Summary The Drosophila fauna of a deciduous flood plain forest rich in undergrowth near the river Isar, close to Munich, Germany, was surveyed in summer 1990. Decaying herbage baits (decay artificially induced) were set out to study the exploitation of that resource by Drosophila. Sixteen plant species belonging to several families dominant in the collecting area were tested. All attracted and produced drosophilid flies. Ten Drosophila species utilized decaying plant material as breeding sites; at least eight of the ten are polyphagous. Decaying stalks and leaves of Angelica sylvestris (Apiaceae) were examined in detail. In the case of the most frequent species of Drosophila attracted to A. sylvestris, the number of adults collected did not correlate with the number of flies emerging from the substrate. This was particularly true of D. limbata and D. phalerata. When oviposition and larval development of D. limbata and D. phalerata on A. sylvestris was tested in the laboratory, the number of offspring per female was the same in both species. The difference between these two species of the quinaria group in the exploitation of A. sylvestris in the field is therefore not due to differential suitability of the substrate.
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  • 62
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    Sexual plant reproduction 5 (1992), S. 64-71 
    ISSN: 1432-2145
    Keywords: Generative cell ; Isolation ; Microtubules ; Ultrastructure
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    Topics: Biology
    Notes: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
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    Sexual plant reproduction 5 (1992), S. 27-33 
    ISSN: 1432-2145
    Keywords: Isolated generative cells ; Ultrastructure ; Microtubule ; Immunofluorescence microscopy ; Allemanda neriifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of isolated generative cells ofAllemanda neriifolia at interphase and prophase was studied. The microtubule organization of the isolated cells was also investigated by immunofluorescence microscopy with a monoclonal anti-α-tubulin. After the generative cells had been isolated from the growing pollen tubes by osmotic shock, most of the cells were at prophase and only a few were at interphase. The interphase cell is spindle shaped and contains an ellipsoidal nucleus. In addition to the usual organelles, the cytoplasm of the interphase cell contains numerous vesicles (each measuring 40–50 nm in diameter) and two sets of longitudinally oriented microtubule bundles — one in the cortical region and the other near the nucleus. Most of the prophase cells are spherical in shape. Based on the ultrastructure and the pattern of microtubule cytoskeleton organization three types of prophase cells can be recognized. (1) Early prophase cell, which contains the usual organelles, numerous vesicles, and a spherical nucleus with condensed chromosomes. Longitudinally oriented microtubule bundles can no longer be seen present in the early prophase cell. A new type of structure resembling a microtubule aggregate appears in the cytoplasm. (2) Mid prophase cell, which has a spherical nucleus containing chromosomes that appear more condensed than those seen in the early prophase cell. In addition to containing the usual organelles, the cytoplasm of this cell contains numerous apparently randomly oriented microtubules. Few vesicles are seen and microtubule aggregates are no longer present. (3) Late prophase cell, typified by the lack of a nuclear envelope. Consequently, the chromosomes become randomly scattered in the cytoplasm. Microtubules are still present and some become closely associated with the chromosomes. The changes in the ultrastructure and in the pattern of microtubule organization in the interphase and prophase cells are discussed in relation to the method of isolation of the generative cells.
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    Sexual plant reproduction 5 (1992), S. 131-137 
    ISSN: 1432-2145
    Keywords: Pollen grain ; Generative cell ; Formation and detachment ; Ultrastructure ; Polystachia pubescens ; Orchidaceae
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    Topics: Biology
    Notes: Summary The formation and nature of the generative cell wall and the detachment mode of the generative cell from the intine in Polystachia pubescens were observed by LM and TEM. Vesicles evenly positioned within the phragmoplast fuse to form a cell plate that divides the microspore into the generative and vegetative cell. This cell plate consists of callose. Before the generative cell leaves the intine, however, the callose is completely resorbed and is not replaced by any other substance. The generative cell becomes detached from the intine by moving towards the centre of the pollen grain. A constriction formed thereby gives the generative cell a bulb-like appearance and leads ultimately to the generative cell being pinched off. Plasma-filled vesicles originating from the generative cell remain between the intine and the plasma membrane of the vegetative cell.
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  • 65
    ISSN: 1432-072X
    Keywords: Mating tube ; Microtubule ; Tremella ; Ultrastructure ; Yeast
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    Topics: Biology
    Notes: Abstract Ultrastructure of the mating tube formed in yeast haplont of the heterobasidiomycete Tremella mesenterica was studied by electron microscopy. Cell wall of the mating tube emerged as evagination of the inner layers, rupturing outer layers of the mother cell wall. Comparison with budding cells suggested that the tube emergence place at bud scar and the process of tube emergence was the same as that of bud emergence. Electron transparent vesicles of 0.1 μm diameter were scattered in the cytoplasm of the mating tube. Nucleus-associated organelle was located at one side of the nuclear envelope which extended towards the mating tube. A few microtubules were detected in the mating tube, but their association with a nucleus was not clear. The cytoplasmic structure of the mating tube was discussed in comparison with that of hyphae of the filamentous fungi.
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  • 66
    ISSN: 1432-072X
    Keywords: Claviceps purpurea ; Ultrastructure ; Development ; Sclerotium ; Oleosomes
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    Topics: Biology
    Notes: Abstract The development of sclerotia of Claviceps purpurea was investigated by light and electron microscopy. During the first days after infection sterigma and conidiospores are formed. The spores show a moderately developed vacuolar system, they are thick walled and contain about 20% lipid (related to the cell volume) embedded in glycogen. The sterigma are cylindrical unicellular hyphae with electron dense cytoplasm and isolated strongly contrasted lipid droplets. In maturing sclerotia the hyphae become septated with increasingly thick cell walls and a large lipid content. The lipid forms small droplets in young cells, while in the mature sclerotium it occurs in the form of very large drops, occupying the major part of the cell. Simultaneously the composition of the lipid is changed. The mature cells have several nuclei. They are partially connected by osmiophilic substances, forming a network of intercellular spaces.
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    Archives of microbiology 158 (1992), S. 249-255 
    ISSN: 1432-072X
    Keywords: Sporulation ; Meiosis ; Ultrastructure ; Spindle pole body ; Spo mutants ; Schizosaccharomyces pombe ; Fission yeast
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    Topics: Biology
    Notes: Abstract A homothallic haploid strain of the fission yeast Schizosaccharomyces pombe initiates sexual reproduction (mating, meiosis and sporulation) in nitrogen-free sporulation medium. Cellular fine structures of eleven sporulation-deficient mutants (spo2, spo3, spo4, spo5, spo6, spo13, spo14, spo15, spo18, spo19 and spo20) of S. pombe in sporulation medium were examined by serial section-electron microscopy. The striking features of these spo mutants were: 1) the disappearance of the spindle pole bodies (SPBs) after the second meiotic division, and 2) the accumulation of unorganized structures. Based on histochemical staining, these structures were presumably unorganized spore wall precursors. In some mutants (spo3, spo5, spo6, spo19 and spo20), diploid zygotes contained four spore-like bodies which had walls similar to complete spore walls but failed to enclose any nuclei. After completion of the second meiotic division the nuclei were abnormally distributed in zygotic diploid cells. In the spo5, spo13, spo14, spo15 and spo19 mutants, the nuclei remained attached to each other. In spo5 and spo19, the inner membrane of the nuclear envelope was separated, but its outer membrane was shared by two sister nuclei. These observations suggest that the spo+ gene products play important roles in spatial and temporal organization of cellular structures during ascospore development.
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  • 68
    ISSN: 1432-072X
    Keywords: Intercellular junctions ; Multicellularity in prokaryotes ; Bacterial magnetotaxis ; Ultrastructure ; Bacterial co-ordination
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    Notes: Abstract A many-called magnetotactic prokaryote obtained from brackish water was observed to possess intercellular connections at points of contact between the outer membranes of constituent cells. Each aggregate organism consisted of 10 to 30 individual Gram-negative cells containing material with the appearance of poly-β-hydroxybutyrate and magnetosomes of unusual arrangement, structure and composition. The aggregate, which possessed prokaryotic-type flagella arranged at the outwards surfaces of each cell, showed motility indicative of co-ordination between individual component cells. These results suggest that this organism could be a multicellular prokaryote.
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    Archives of microbiology 134 (1983), S. 295-298 
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
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    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
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  • 70
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
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    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
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  • 71
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    Archives of microbiology 157 (1992), S. 319-322 
    ISSN: 1432-072X
    Keywords: Chlorobiaceae ; Spinae ; Chlorobium ; Ultrastructure
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    Topics: Biology
    Notes: Abstract Several Chlorobium species have been observed to possess spinae. Spinae are non-prosthecate, helically wound, rigid structures that extend from the outer bacterial cell surface into the external environment. Spinae length was variable within and between Chlorobium species. Spinae width was fairly consistent within species but varied between species (39.4 ± 2.6 nm to 82.6 ± 8.0 nm). The number of spinae per cell varied. The spinae did not penetrate the bacterial cell envelope and were randomly located on the cell surface. Spinae were not geographically restricted. The observation of spinae on pure cultures of Chlorobium spp. maintained for 25–30 years suggests that spinae may be of significant use to the cell.
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  • 72
    ISSN: 1432-2285
    Keywords: Arbutus unedo ; Laccaria amethystea ; Mycorrhiza ; Synthesis ; Ultrastructure
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    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Anatomy and ultrastructure of the arbutoid mycorrhiza of Arbutus unedo-Laccaria amethystea from axenic culture are described. In comparison to non-inoculated roots, the rhizodermal cells of mycorrhizas are of greater volume, their nuclei are enlarged and show an irregular shape, plasmalemma and cytoplasm with mitochondria, plastids, endoplasmic reticulum and dictyosomes are increased. Several ontogenetical states are documented. The arbutoid mycorrhiza as a connecting link between ectomycorrhiza and ericoid mycorrhiza is discussed.
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  • 73
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    Behavior genetics 20 (1990), S. 535-543 
    ISSN: 1573-3297
    Keywords: Drosophila ; speciation ; sexual isolation ; behavior
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    Topics: Biology , Psychology
    Notes: Abstract Drosophila mojavensis from the Sonora region and Baja California show asymmetrical sexual isolation in the laboratory: males from Sonora mate equally frequently with Sonora and Baja females, while the mating success of Baja males with Sonora females is reduced. This failure has been localized to three separate behavioral landmarks occurring during courtship. Genetic analysis was conducted using reciprocal F1 hybrids of Sonora and Baja strains to examine inheritance patterns of the responsible courtship behaviors. Mating success and propensity of F1 males were similar to Sonora males. F1 females mated with males of Sonora and Baja races equally, although mating propensity of F1 females was intermediate between that of Sonora and Baja females. Males of Baja strains presented with F1 females showed a relatively high level of failure at attempted intromission. Genes for mating behaviors are located in the autosomes, but different loci responsible for the sexual isolation appear to act in males and females.
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  • 74
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    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Keywords: Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
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  • 75
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    Biochemical genetics 21 (1983), S. 199-211 
    ISSN: 1573-4927
    Keywords: Drosophila ; lactate dehydrogenase ; isozymic pattern ; development ; isozymic conversion
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Partially purified lactate dehydrogenase (LDH) from third-instar larvae displays two bands (one major and one minor) on polyacrylamide gels. Analogous preparations from pupae and adults exhibit three LDH-staining bands (one major and two minor) in a similar pattern. The migration of the major band is similar for larvae, pupae, and adults, while the two minor LDH bands of pupae and adults migrate more slowly than the minor larval band. It has been shown that larval LDH incubated with β-nicotinamide adenine dinucleotide exhibits two additional minor bands with an electrophoretic mobility similar to that of the minor bands of both pupae and adults. The intensity of the minor larval LDH band (exhibited also by untreated preparations) is drastically reduced. This fact indicates that the life-cycle stage-dependent LDH isozymic distribution is possibly due to a posttranslational effect(s). Highly purified LDH from larvae, pupae, or adults, obtained by an affinity chromatography procedure, displays just one dispersed band, located in the area between the band 5 and the band 6 exhibited by crude extract preparations. These data, in combination with the lack of difference in catalytic properties among enzymes from larvae, pupae, and adults, suggest that LDH synthesis is controlled by the same single structural gene at all developmental stages.
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  • 76
    ISSN: 1573-4927
    Keywords: Drosophila ; alcohol dehydrogenase ; enzyme polymorphisms, activity ratios
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Representatives of five allozymic classes of Drosophila alcohol dehydrogenase have been compared with respect to their activity levels on two alcohol substrates, quantities of ADH protein, and stability in crude extracts. Within each allozymic class, strains from widely diverse geographic locations differ in their enzyme activity levels but are identical for a measure known as “activity ratio,” which is obtained by dividing the average activity reading on isopropanol by that obtained with ethanol. They are also similar in the rate at which ADH activity declines in crude extracts held at 25°C. For several of the fast-resistant and fast-moderate strains, differences in ADH activity are associated with differences in the amount of enzyme present. The catalytic efficiencies of the fast-resistant forms are considerably lower than those of the fast-moderate allozymes. The origin and persistence of the rare but ubiquitous fast-resistant allozyme is discussed.
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  • 77
    ISSN: 1573-4927
    Keywords: Drosophila ; ontogeny ; amylase ; α-glucosidases ; functional significance
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Changes in amylase (E.C. 3.2.1.1), maltase (E.C. 3.2.1.20), sucrase, and PNPGase activities in relation to changes in wet weight and protein content were studied during the development of larvae and adult flies from two strains of Drosophila melanogaster, homozygous for different amylase alleles. All α-glucosidase activities increase exponentially during a large part of larval development, parallel to the increase in weight, and drop at the end of the third instar. Amylase activity of the Amy 1 strain follows the same pattern. In contrast, amylase activity of the Amy 4,6 strain continues its exponential increase longer. In the third larval instar amylase activity in the Amy 4,6 strain becomes much higher than in the Amy 1 strain. During the first hours of adult life amylase activity of the two strains does not differ. Then Amy 4,6 activity starts to rise and becomes much higher (4–5 times) than Amy 1 amylase activity, which remains approximately constant. All adult enzyme activities are much higher than in larvae. Comparison of enzyme activity of amylase and α-glucosidases in larvae and adults confirms that differences in amylase activities can become important only when starch is a limiting factor in the food.
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  • 78
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    Biochemical genetics 18 (1980), S. 439-454 
    ISSN: 1573-4927
    Keywords: Drosophila ; acetylcholinesterase ; insecticide resistance ; electrophoretic variation
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We examined the Canton-S strain of Drosophila melanogaster for electrophoretic variation of the enzyme acetylcholinesterase. The pattern of bands obtained (stained with acetylthiocholine) depended on age, sex, and tissue (i.e., head vs. body part and hemolymph). However, through mixing experiments, it was concluded that most of these apparent differences were due to modification of the enzyme by unknown substances located in the fly's body. The electrophoretic pattern of head acetylcholinesterase was altered so that it became characteristic of the body which was present during extraction. For example, when heads of D. melanogaster were homogenized in an extract from D. lebanonensis bodies, the characteristic AChse bands of melanogaster were absent and instead the bands of lebanonensis were found. it was found that extraction of adult heads in 0.1 M potassium phosphate buffer alone or with a 2-min exposure to 1 mg/ml trypsin at 20 C gave the most reproducible results, independent of age and sex. Using these conditions, 25 strains of D. melanogaster and 30 strains of D. pseudoobscura were examined without finding any reproducible electrophoretic variant of acetylcholinesterase. In addition, 53 strains from 39 other Drosophila species produced a total of only six electrophoretic forms of the head enzyme. Additional electromorphs were found when whole flies were used, but these were not studied in detail because of the possibility that they could be due to postextraction modification.
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    Biochemical genetics 18 (1980), S. 717-726 
    ISSN: 1573-4927
    Keywords: Drosophila ; 5-fluorouracil ; drug response ; thymidylate synthetase
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mutant strains sensitive and resistant to the drug 5-fluorouracil (FU) have been isolated from the wild-type Pac strain of Drosophila melanogaster. The resistant strain, termed flur, is resistant to at least 0.0035%FU (2.7 × 10−4 m) in the food media and exhibits cross-resistance to 5-fluorodeoxyuridine (FUdR) but not to 5-fluorouridine (FUR). The sensitive strain termed flu S , exhibits over 90% mortality on 0.0008% FU (6 × 10−5 m). Genetic analysis indicates that the flu gene is located on the third chromosome, which agrees with results of previous workers. An analysis of the enzyme thymidylate synthetase from the selected sensitive and resistant strains indicates that the resistant strain enzyme possesses an elevated specific activity. Levels 4 times that of the sensitive strain were observed when the enzymes were assayed at 20 C. This increase is apparently not due to induction by FU in the food media. It is suggested that the enzyme thymidylate synthetase may be involved in the resistance process.
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  • 80
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    Biochemical genetics 18 (1980), S. 781-791 
    ISSN: 1573-4927
    Keywords: Drosophila ; phenylalanine hydroxylase ; developmental regulation
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Herein we demonstrate that Drosophila larvae possess a synthetic activity capable of converting phenylalanine to tyrosine. This system is readily extractable and displays many characteristics of phenylalanine hydroxylase systems described in other organisms, the most notable being that a tetrahydropteridine is required for full expression of activity. The level of phenylalanine hydroxylase activity present in the organism varies with the stage of development: from an undetected level of activity at the first larval instar, there is a rapid increase in phenylalanine hydroxylase activity which reaches a peak at the time of puparium formation, after which there is a rapid decrease again to an undetected level.
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  • 81
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    Biochemical genetics 18 (1980), S. 929-937 
    ISSN: 1573-4927
    Keywords: glucose oxidase ; glucose metabolism ; Drosophila ; sex specific
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A glucose oxidase (GO) has been identified in the ejaculatory duct of male Drosophila melanogaster. Evidence is given that this enzyme was previously misidentified as HEX-1. Genetic analysis indicates that the Go structural gene is located on the third chromosome at 48 ± 0.5 cm. Go is polymorphic in males in populations of D. melanogaster and D. simulans located in Athens, Georgia. Two other hexose enzymes have also been tentatively identified for the first time in Drosophila. These are NAD(P)-glucose dehydrogenase (GODH) and NAD-gluconate dehydrogenase (GNDH). GODH and GNDH are found in both males and females and may circumvent the initial steps in the pentose shunt.
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  • 82
    ISSN: 1573-4927
    Keywords: Drosophila ; glycerol-3-phosphate dehydrogenase ; aldolase ; phosphoglycerate kinase ; enzyme induction
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The genes encoding glycolytic enzymes inDrosophila form a group of functionally related genes that may be coordinately regulated and thus controlled by common factors. We have examined the effect of dietary carbohydrates and ethanol on expression of the genes encoding glycerol-3-phosphate dehydrogenase (GPDH), aldolase (ALD), and phosphoglycerate kinase (PGK) inD. melanogaster larvae. GPDH activity and transcript abundance increased in response to ethanol and additional amounts of several different carbohydrates. In addition, the levels of two alternatively processedGpdh transcripts were differentially regulated by the treatments. The nutritional conditions tested had little or no effect on the activities and transcript levels of ALD and PGK. These results indicate that changes in dietary conditions affect expression of specific genes and do not evoke a general response from genes involved in cellular metabolism. The observation that dietary carbohydrates and ethanol increaseGpdh expression without affecting expression ofAld andPgk reinforces previous suggestions that dietary carbon can be diverted by GPDH from glycolytic catabolism into lipid biosynthesis.
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  • 83
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    Biochemical genetics 21 (1983), S. 703-711 
    ISSN: 1573-4927
    Keywords: Drosophila ; glucose-6-phosphate dehydrogenase ; polymorphism ; sequential electrophoresis
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Studies were undertaken to investigate two critical aspects of the glucose-6-phosphate dehydrogenase polymorphism in Drosophila melanogaster. The first investigation unequivocally maps the genetic site of the G6PD locus to the X chromosome. The second study subjects a set of isochromosomal lines to sequential electrophoresis in an attempt to uncover common molecular heterogeneity within the global polymorphism, assuming that this variation may have gone undetected under conventional electrophoretic conditions. The genetic site was mapped following the segregation of the two common electrophoretic alleles, a so-called null allele, and two rare electrophoretic variants. From the pooled results, the Zw locus mapped to 62.9 on the X chromosome relative to the flanking markers car (at 62.5) and sw (at 64.7). A set of 126 iso-X chromosomal lines of diverse geographic origin was subjected to sequential electrophoresis under three different acrylamide conditions in addition to the conventional starch electrophoretic system. No additional variation beyond the common diallele polymorphism was seen.
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  • 84
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    Behavior genetics 10 (1980), S. 401-407 
    ISSN: 1573-3297
    Keywords: sexual isolation ; Drosophila ; geographic distance ; isolation index ; resource utilization
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    Topics: Biology , Psychology
    Notes: Abstract Six strains of the cosmopolitan speciesD. immigrans from the Australian life zone plus one from the USA, show weak sexual isolation and more rarely sexual selection. Levels of sexual isolation cannot be related to geographic distances. Assortative mating may have evolved as a byproduct of ecological divergence.
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  • 85
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    Behavior genetics 13 (1983), S. 17-27 
    ISSN: 1573-3297
    Keywords: pupation site ; pupation height ; artificial selection ; Drosophila ; density-dependent behavior ; genotype-environment interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Selection for increased pupation height was carried out for 17 generations in two lines ofDrosophila simulans derived from a genetically heterogeneous base population. The realized heritability for mean pupation height in each line, calculated over the 17 generations, did not differ significantly from zero. Both selected lines tended to pupate away from the center of the culture medium to a greater extent than the control in the latter generations of the experiment but not in earlier generations. Pupation height may have been refractory to artificial selection because of an adaptation of this species to pupate on the larval food source. In a subsequent experiment, each line was tested at three larval densities in an apparatus different from the one used for selection. Each successively higher density showed a corresponding increase in pupation height. Both selected lines had higher mean pupation heights than the control line. The differences between lines became more pronounced as the larval density increased.
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  • 86
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    Behavior genetics 20 (1990), S. 73-79 
    ISSN: 1573-3297
    Keywords: Drosophila ; mating behavior ; mate choice ; anesthesia ; etherization ; genetic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Genetic differences that influence mating preferences were studied in genetically defined lines ofDrosophila melanogaster. Initial results suggested substantial differences between two types of females with respect to the types of male preferred as mates, but further experimentation showed that the mating patterns were conditional on the mode of anethesia (CO2 versus ether). In a statistical test of independence, the major determinant of mating choice in these experiments was due to an interaction effect between genotypes and mode of anesthesia. The observations might be explained by the differential sensitivity of male genotypes to ether. Etherization at emergence has lasting effects on mating behavior; it alters not only the latency and frequency of mating 4 days later, but also the pattern of matings observed.
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  • 87
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    Biochemical genetics 21 (1983), S. 365-374 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; NAD+ levels ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Previous studies carried out in mammalian systems indicated that an organism's NAD+/NADH balance is carefully regulated but can be destabilized by dietary stresses. Since Drosophila alcohol dehydrogenase (ADH) uses NAD+ to remove a hydrogen from ethanol in the first step of alcohol catabolism, it is possible that under alcohol stress conditions the in vivo NAD+ levels in Drosophila may decrease. In this study genetically homozygous flies were stressed with maximally sublethal concentrations of ethanol (10%) for periods of up to 24 hr. The results indicate that NAD+ levels do in fact drop by at least 20% in response to ethanol stress. Evidence is presented that suggests that this decrease is the direct result of ADH-mediated catabolism.
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  • 88
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    Behavior genetics 22 (1992), S. 469-487 
    ISSN: 1573-3297
    Keywords: courtship ; pheromones ; Drosophila ; apterous ; juvenile hormone ; reproductive development ; sexual behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Theapterous (ap) gene ofDrosophila melanogaster exhibits extreme pleiotrophy: its functioning is essential for life, normal wing structure, juvenile hormone production, female fertility, and normal development of female sexual receptivity. Four mutantap alleles (ap 4,ap 56f,ap c, andap blt) were characterized for three additional phenotypes: male mating success, courtship behavior, and immature male sex appeal (the ability of males to stimulate homosexual cortship). Mating success with mature wild-type virgin females is reduced in males mutant for theap gene, the extreme case beingap 4/ap 4 males, which are behaviorally sterile. Inap mutants, nonwing courtship elements are qualitatively like those ofap +/ap + males. However, the mean rate of nonwing courtship directed toward virgin wild-type females (i.e., the mean temporal frequency of these displays) is reduced in males homozygous forap 4,ap 56f, orap c alleles. In contrast, theap blt allele makes for wild-type rates of nonwing courtship. Immature male sex appeal persists for at least 3 days in males homozygous forap c and, to a lesser extent, inap 56f orap 4 homozygotes;ap blt/ap blt and wild-type males lose immature male sex appeal after 1 day. All three male phenotypes map to theap locus, which is therefore essential for the development of normal levels of male courtship and male mating success and for the timely loss of immature male sex appeal. For each phenotype,ap + is dominant toap alleles making for behavioral abnormalities, with a single exception (for rate of nonwing courtship,ap +/ap c was low). For mating success and frequency of nonwing courtship, each allele pair exhibits at least partial complementation, except forap 4 andap 56f, which fail to complement. For immature male sex appeal,ap c,ap 4, andap 56f fall into the same complementation group. Juvenile hormone production is not correlated with effects on male reproductive behavior.
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    Behavior genetics 22 (1992), S. 557-573 
    ISSN: 1573-3297
    Keywords: Drosophila ; biometrical analysis ; behavior genetics ; genetic analysis ; ss a ; deletion mapping
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    Topics: Biology , Psychology
    Notes: Abstract The homeotic mutationspineless-aristapedia (ss a ) transforms the aristae into second tarsi. Flies with aSS a phenotype also show extremely positive geotaxis as measured in a Hirsch-type geotaxis maze. Other antennal mutants and flies with their aristae amputated do not show such extreme positive geotaxis. Deletion analysis has comapped the geotaxis effect withSS a in band 89C on the third chromosome. Finally, a biometrical analysis has detected additional genes on the X chromosome that also affects geotaxis.
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    Biochemical genetics 30 (1992), S. 159-168 
    ISSN: 1573-4927
    Keywords: Drosophila ; indirect flight muscle ; tropomyosin ; polymorphism
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We describe polymorphism in aDrosophila indirect flight muscle-specific tropomyosin isozyme, named TnH-34. Three variants of this protein differ in their mobilities as determined by 1-D and 2-D SDS-PAGE. Meiotic mapping places the polymorphism close to, if not within, the structural gene encoding this tropomyosin isozyme. The most likely site of the mutations is within a single C-terminal exon. Flight-testing of different genotypes reveals that this variation in TnH-34 does not affect flight ability. These results suggest that some sequence variation may be tolerated in this section of the protein and correlate with the variability of this protein in different insect species.
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    Biochemical genetics 30 (1992), S. 305-315 
    ISSN: 1573-4927
    Keywords: Drosophila ; diaphorase ; purification ; kinetics ; immunochemical characteristics
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diaphorase-1 and diaphorase-2 were isolated from twoDrosophila species,D. virilis andD. melanogaster, and purified by gel filtration, affinity chromatography, immunoaffinity chromatography, and ion-exchange chromatography. The molecular weights of both enzymes were the same in each species. The molecular weight of diaphorase-1 was the same under both denaturating and nondenaturating conditions, close to 60,000, indicating a monomeric structure. Sodium dodecyl sulfate (SDS) electrophoresis of the purified diaphorase-2 revealed the presence of a single protein band of 55,000 Da, while the molecular weight of the native enzyme was found to be 67,000. The two diaphorases were further characterized by their pH optima, isoelectric points, and kinetic parameters, and antibodies were raised in rabbits against the purified enzymes fromD. virilis. The antibodies showed no cross-reactions but recognized the corresponding diaphorases inD. melanogaster andD. novamexicana as well asD. virilis. The data obtained confirmed the hypothesis of an independent genetic control of diaphorase-1 and diaphorase-2 inDrosophila.
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    Biochemical genetics 30 (1992), S. 305-315 
    ISSN: 1573-4927
    Keywords: Drosophila ; diaphorase ; purification ; kinetics ; immunochemical characteristics
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diaphorase-1 and diaphorase-2 were isolated from twoDrosophila species,D. virilis andD. melanogaster, and purified by gel filtration, affinity chromatography, immunoaffinity chromatography, and ion-exchange chromatography. The molecular weights of both enzymes were the same in each species. The molecular weight of diaphorase-1 was the same under both denaturating and nondenaturating conditions, close to 60,000, indicating a monomeric structure. Sodium dodecyl sulfate (SDS) electrophoresis of the purified diaphorase-2 revealed the presence of a single protein band of 55,000 Da, while the molecular weight of the native enzyme was found to be 67,000. The two diaphorases were further characterized by their pH optima, isoelectric points, and kinetic parameters, and antibodies were raised in rabbits against the purified enzymes fromD. virilis. The antibodies showed no cross-reactions but recognized the corresponding diaphorases inD. melanogaster andD. novamexicana as well asD. virilis. The data obtained confirmed the hypothesis of an independent genetic control of diaphorase-1 and diaphorase-2 inDrosophila.
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    Biochemical genetics 30 (1992), S. 77-83 
    ISSN: 1573-4927
    Keywords: acetylcholinesterase ; insecticide ; resistance ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Selection of field populations originating from several countries allowed us to isolate 13 strains ofDrosophila melanogaster resistant to parathion.In vitro studies of acetylcholinesterase inhibition by paraoxon have been carried out on purified enzymes: most of the resistant strains harbor an altered acetylcholinesterase. Enzymes with higher resistance levels have been characterized with respect to their cross-resistance toward several insecticides. The patterns obtained have permitted us to group them and to delineate four categories. The existence of four distinct types of protein suggests that several mutations of acetylcholinesterase are responsible for insecticide resistance inDrosophila.
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  • 94
    ISSN: 1573-4927
    Keywords: Drosophila ; glycerol-3-phosphate dehydrogenase ; restriction map ; duplication ; enzyme activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Restriction site variation in a 25-kb region including thesn-glycerol-3-phosphate dehydrogenase (Gpdh) locus has been assessed in 29 single femaleD. melanogaster lines from the Cardwell (Australia, QLD) population. TheGpdh locus was duplicated in about one-third of the lines, although the duplication was incomplete and lacked exons 1 and 2. There was no restriction site variation in the duplicated region. Three insertions were found in the gene region but only one affected GPDH activity. The lines with the duplication had higher levels of GPDH activity and protein amount than did nonduplicated lines. This effect was also observed in lines extracted from two other Australian populations. The duplication is shown to have a similar structure in each population investigated and is also present in populations from China and Africa. It is suggested that the effect of the duplication on GPDH activity, which might be due to structural factors affecting transcription at theGpdh locus, could account for the worldwide distribution of the duplication.
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  • 95
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    Biochemical genetics 30 (1992), S. 515-527 
    ISSN: 1573-4927
    Keywords: glutathioneS-transferase ; Drosophila ; cellular detoxification ; pesticide resistance ; insect metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have isolated aDrosophila gene,DmGST-2, that encodes glutathioneS-transferase, a homo- or heterodimeric enzyme thought to be involved in detoxification of xenobiotics, including known carcinogens. The encoded protein has a primary sequence that is more similar to mammalian placental and nematode GSTs than that of a previously describedDrosophila GST gene, herein referred to asDmGST-1. We provide a physical map of the gene and show that it specifies at least two mRNAs, measuring 1.9 and 1.6 kb, which differ only in the lengths of their 3′ untranslated regions. Both of the mRNAs are present during all developmental stages.In situ hybridization of theDmGST-2 gene to larval polytene chromosomes places it within the 53F subdivision of chromosome 2, and Southern blotting to chromosomal DNA indicates that the gene has no close relatives within theDrosophila genome. Our results make possible molecular genetic approaches for further elaborating the function of glutathioneS-transferases in insect development and physiology, in the metabolism of plant toxins, and in conferring insecticide resistance.
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  • 96
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    Journal of comparative physiology 167 (1990), S. 437-440 
    ISSN: 1432-1351
    Keywords: Mechanosensory neuron ; Sensory fatigue ; cAMP cascade ; Drosophila ; Memory mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have investigated the effect of systemic treatment with drugs that affect the cAMP cascade on the sensory response and sensory fatigue in an identified mechanosensory neuron of Drosophila. Forskolin, an activator of adenylate cyclase, decreases the sensory response of the neuron. H7, an inhibitor of protein kinase, inhibits sensory fatigue. Octopaminergic ligands facilitate sensory fatigue. These results, together with our previous neurogenetic analysis of sensory fatigue in Drosophila (Corfas and Dudai 1990), corroborate the hypothesis that the cAMP cascade is involved in the generation and modulation of sensory fatigue.
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  • 97
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    Theoretical and applied genetics 83 (1992), S. 821-826 
    ISSN: 1432-2242
    Keywords: Drosophila ; Balancers ; Inversions ; Translocations ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We used a screen for maternally generated late embryonic lethals as a new method for the isolation of inversions that are suitable for the balancing of mutations in Drosophila hydei. The recovery of several inversions by this method demonstrates that female meiosis in D. hydei apparently differs from meiosis in female D. melanogaster, since in D. hydei the defective chromosomes which are generated by a single crossing-over within a paracentric inversion can be recovered via the egg nucleus. In addition, the classic method of crossingover suppression was used in order to isolate more inversions and to improve the balancing capacities of inversions. We succeeded in constructing chromosomes that allow the balancing of mutations on nearly the whole genome of D. hydei. We discuss here whether or not this method is suited for application to other organisms.
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  • 98
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    Theoretical and applied genetics 65 (1983), S. 173-180 
    ISSN: 1432-2242
    Keywords: Disruptive selection ; Linkage disequilibrium ; Genetic variance ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Theoretical predictions of changes in variance with disruptive selection have used models of infinitely many genes so the increase in variance was necessarily due to linkage disequilibrium. With small numbers of loci, the disequilibrium is shown still to comprise the major part of the changes in variance. In a replicated experiment with Drosophila melanogaster, disruptive selection was practised for three generations, and this was followed by 5 or 7 generations of random mating. The heritability, as estimated from regression of progeny on parent, rose from 37% to 68% on selection, and subsequently declined to 45% on random mating. Changes of variance can be interpreted invoking the build up of linkage disequilibrium during selection followed by its breakdown upon relaxation. The results agree well with those obtained from Monte Carlo simulation.
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  • 99
    ISSN: 1432-2242
    Keywords: Drosophila ; Enzyme polymorphisms ; Latitudinal clines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The octanol dehydrogenase (Odh) and acid phosphatase (Acph) loci of Drosophila melanogaster are each polymorphic for two electrophoretically detectable alleles. The frequencies of the Odh and Acph alleles have been analysed in populations sampled from up to a 40 ° latitudinal range in each of Australasia, North America and Europe/Asia. Odh S frequency is found to be significantly negatively associated with distance from the equator in all three zones. The relationship of Acph S frequency to distance from the equator is significant and negative in Australasia but neither significant nor consistent in sign in North America and Europe/Asia.
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  • 100
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    Theoretical and applied genetics 80 (1990), S. 321-325 
    ISSN: 1432-2242
    Keywords: Heterosis ; Genetic distance ; Drosophila ; Inbreeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The aim of the experiment was to determine if the estimated genetic distance between two populations could be used to predict the amount of heterosis that would occur when they were crossed. Eight lines of known relatedness to each other were produced by eight generations of sib mating and sub-lining. This produced lines that varied in coefficient of coancestry from zero to 0.78. Fourteen reciprocal crosses of these lines were used to measure heterosis for larval viability and adult fecundity. Gene frequencies at six polymorphic enzyme loci were used to estimate the genetic distances between lines, which were then compared with the known degrees of coancestry. The estimated genetic differences were poorly correlated with the known coancestry coefficients (r=0.4), possibly due to the small number of loci typed. Also genetic distances were only about 1/3 of what was expected. Selection acting on blocks of genes linked to the enzyme loci probably prevented the expected increase in homozygosity. Coancestry coefficient was correlated with heterosis (r=0.44–0.71). This level of correlation implied differences in heterosis among parent lines with the same level of coancestry. This variability is expected if a small number of loci explain most of the heterosis. The average level of heterosis was less than expected after eight generations of sib mating. This is most likely due to selection opposing the increase in homozygosity caused by inbreeding. The combination of these two imperfect correlations resulted in no significant correlation between genetic distance estimated from markers and heterosis.
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