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  • Rat  (826)
  • Drosophila  (737)
  • Springer  (1,562)
  • Nature Publishing Group
  • Blackwell Publishing Ltd
  • American Institute of Physics (AIP)
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  • 1
    Electronic Resource
    Electronic Resource
    Behavioural induction in Drosophila: timing and specificity (2000)
    Springer
    Entomologia experimentalis et applicata 94 (2000), S. 159-171 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; induction ; habituation ; associative learning ; T-maze olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments reported in this paper investigate the properties of a change in the responsiveness of adult Drosophila melanogaster induced by exposure to different rearing media. This effect has previously been described as habituation or associative learning. Exposure to food medium containing 0.08% menthol induced a positive response to menthol odour in a T-maze olfactometer. A brief (one hour) exposure to mentholic food just before testing was sufficient to induce a change in responsiveness. The effect did not persist through periods of more than an hour of separation from mentholic medium. Effects induced by exposure to a single compound were not specific to that compound alone. Menthol-reared flies (MRFs) differed from plain reared flies (PRFs) in their responsiveness to the odours of benzaldehyde and ethyl acetate, as well as menthol, and exposure to ethyl acetate induced a change in response to menthol odour. That there was an induced positive response to menthol in MRFs suggests that conventional habituation is insufficient to explain the induced change in responsiveness, but the generalised nature of this behavioural induction in MRFs is hard to explain in terms of associative learning. The mechanism underlying the induction remains elusive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003998715018
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  • 2
    Electronic Resource
    Electronic Resource
    Lack of Evolutionary Divergence in Courtship Songs of Drosophila pseudoobscura Subspecies (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 255-262 
    Details
    ISSN: 1572-8889
    Keywords: courtship song ; wingbeat ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007744416116
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  • 3
    Electronic Resource
    Electronic Resource
    Copulatory Courtship in Drosophila birchii and D. serrata, Species Recognition and Sexual Selection (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 361-373 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; copulatory courtship ; mate choice ; cryptic female choice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two endemic Australian Drosophila species, D. birchii and D. serrata, have a copulatory courtship, i.e., the males court the female mainly during copulation. In the present study we found the males of both species to mount their prospective mating partners selectively, exhibiting both sex and species recognition. The males began to sing after mounting the female, and they often exhibited also postcopulatory displays typical to copulatory courtship. D. birchii and D. serrata females discriminated against males which did not sing during mounting/copulation, which suggests that the females utilize cryptic female choice. Our findings raise the question of how widespread a phenomenon cryptic female choice is in Drosophila species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007710218609
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  • 4
    Electronic Resource
    Electronic Resource
    Patterning defects in the primary axonal scaffolds caused by the mutations of the extradenticle and homothorax genes in the embryonic Drosophila brain (2000)
    Springer
    Development genes and evolution 210 (2000), S. 289-299 
    Details
    ISSN: 1432-041X
    Keywords: Key words Brain development ; Axonal scaffold ; Extradenticle ; Homothorax ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During early brain development in Drosophila a highly stereotyped pattern of axonal scaffolds evolves by precise pioneering and selective fasciculation of neural fibers in the newly formed brain neuromeres. Using an axonal marker, Fasciclin II, we show that the activities of the extradenticle (exd) and homothorax (hth) genes are essential to this axonal patterning in the embryonic brain. Both genes are expressed in the developing brain neurons, including many of the tract founder cluster cells. Consistent with their expression profiles, mutations of exd and hth strongly perturb the primary axonal scaffolds. Furthermore, we show that mutations of exd and hth result in profound patterning defects of the developing brain at the molecular level including stimulation of the orthodenticle gene and suppression of the empty spiracles and cervical homeotic genes. In addition, expression of a Drosophila Pax6 gene, eyeless, is significantly suppressed in the mutants except for the most anterior region. These results reveal that, in addition to their homeotic regulatory functions in trunk development, exd and hth have important roles in patterning the developing brain through coordinately regulating various nuclear regulatory genes, and imply molecular commonalities between the developmental mechanisms of the brain and trunk segments, which were conventionally considered to be largely independent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050316
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of a swallow homologue from Drosophila pseudoobscura (2000)
    Springer
    Development genes and evolution 210 (2000), S. 157-161 
    Details
    ISSN: 1432-041X
    Keywords: Key words Swallow ; bicoid ; Drosophila ; mRNA localization ; Oogenesis ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We analyzed a functional homologue of the swallow gene from Drosophila pseudoobscura. The swallow gene of D. melanogaster plays an essential role in localizing bicoid mRNA in oocytes, and swallow mutant embryos show anterior pattern defects that result from the lack of localization of the bicoid morphogen. The pseudoobscura homologue rescues the function of swallow mutants when introduced into the genome of D. melanogaster, and its expression is similar to that of the melanogaster gene. The predicted pseudoobscura and melanogaster proteins are 49% identical and 69% conserved. The coiled-coil domain previously identified in the melanogaster swallow protein is strongly conserved in the pseudoobscura homologue, but the weak similarity of the melanogaster swallow protein to the RNP class of RNA-binding proteins is not conserved in the pseudoobscura homologue. These and other observations suggest a structural role for swallow in localizing bicoid mRNA, perhaps as part of the egg cytoskeleton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050023
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in cell shape in the ventral neuroectoderm of Drosophila melanogaster depend on the activity of the achaete-scute complex genes (2000)
    Springer
    Development genes and evolution 210 (2000), S. 190-199 
    Details
    ISSN: 1432-041X
    Keywords: Key words Ventral neuroectoderm ; Cell shape ; Achaete-scute complex ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In the embryonic ventral neuroectoderm of Drosophila melanogaster the proneural genes achaete, scute, and lethal of scute are expressed in clusters of cells from which the neuroblasts delaminate in a stereotyped orthogonal array. Analyses of the ventral neuroectoderm before and during delamination of the first two populations of neuroblasts show that cells in all regions of proneural gene activity change their form prior to delamination. Furthermore, the form changes in the neuroectodermal cells of embryos lacking the achaete-scute complex, of embryos mutant for the neurogenic gene Delta, and of embryos overexpressing l’sc suggest that these genes are responsible for most of the morphological alterations observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050303
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  • 7
    Electronic Resource
    Electronic Resource
    A polymorphism of the rat T-cell receptor β-chain variable gene 13 (BV13S1) correlates with the frequency of BV13S1-positive CD4 cells (2000)
    Springer
    Immunogenetics 51 (2000), S. 296-305 
    Details
    ISSN: 1432-1211
    Keywords: Key words Vβ13 ; CD4/CD8 ratio ; Rat ; Tcrb ; Polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Three rat BV13S1 alleles (T-cell receptor β-chain variable gene 13) were characterized by new BV13S1-allele specific monoclonal antibodies (18B1 and 17D5) and sequence analysis of expressed and genomic BV13S1. Two alleles were functional and designated BV13S1A1 present in strains LEW, BUF, PVG, and BV13S1A2 present in BN and WF. Their products differed by six amino acids, two of them in complementarity-determing region (CDR)1 and one in CDR2. A third nonfunctional allele, BV13S1A3P, was found in strains F344 and DA. Apart from a single nucleotide insertion, it was identical to BV13S1A2. All 12 rat strains tested showed association of TCRBC1 with BV8S2/4 alleles but not with the BV13S1 alleles, which may reflect a different gene order of the rat BV compared to mouse. BV13S1A1-encoded T-cell receptors (TCRs) which bind both monoclonal antibody (mAb) 18B1 and mAb 17D5 are over-represented in the CD4 lymphocyte subset. BV13S1A2-encoded TCRs which are stained by mAb 18B1 but not by mAb 17D5 show a slight CD8-biased expression. Preferential usage of BV13S1A1-positive TCRs by CD4 but not by CD8 cells in (LEW×WF)F1 hybrids and cosegregation of BV13SA1 and increased frequency of BV13S1 TCR-positive CD4 cells in a (LEW×BN)×BN backcross suggest structural differences of the two allelic products as the reason for their contrasting CD4/CD8 subset bias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002510050623
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  • 8
    Electronic Resource
    Electronic Resource
    Localization of endothelin receptors in bleomycin-induced pulmonary fibrosis in the rat (2000)
    Springer
    Histochemistry and cell biology 122 (2000), S. 507-517 
    Details
    ISSN: 1432-119X
    Keywords: Endothelin-A receptor ; Endothelin-B receptor ; Rat ; Pulmonary fibrosis ; Immunohistochemistry ; Quantitative PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: AbstractPulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ETB receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ETA and ETB receptor mRNA, and ETA receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ETA nor ETB receptor mRNA which were also not induced by bleomycin. We conclude that, while ETB receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ETA receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00418-004-0708-7
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  • 9
    Electronic Resource
    Electronic Resource
    Coexistence of drosophilid flies: Aggregation, patch size diversity and parasitism (2000)
    Springer
    Ecological research 15 (2000), S. 93-100 
    Details
    ISSN: 1440-1703
    Keywords: aggregation ; coexistence ; Drosophila ; parasitism ; patch size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: We carried out field experiments to investigate the coexistence of Drosophila species in domestic and forest areas on the basis of the aggregation model. Three cosmopolitan species Drosophila simulans Sturtevant, Drosophila melanogaster Meigen and Drosophila immigrans Sturtevant, and a native species, Drosophila auraria Peng, emerged abundantly from banana placed at the domestic station, while Drosophila immigrans and five native species, Drosophila lutescens Okada, Drosophila rufa Kikkawa and Peng, Drosophila bizonata Kikkawa and Peng, Drosophila sternopleuralis Okada and Kurokawa and Scaptodrosophila coracina (Kikkawa and Peng), were abundant at the forest station. The present analysis suggests that their coexistence was facilitated by the aggregation mechanism. In the cosmopolitan species, the density of individuals that emerged from patches increased with the increase of patch size, but the relationship between fly density and patch size was not clear in the native species. This difference in distribution patterns between the cosmopolitan and native species is likely to be due to the difference in the female visiting behavior. In the present analysis, however, it was not clear whether patch size diversity facilitated their coexistence or not. The effect of patch size diversity may have been masked, because the effect of aggregation was more prominent. The rate of parasitism by wasps was high in October at the domestic station, and in May and June at the forest station. The present result suggests that the rate of parasitism was density-dependent, at least at the domestic station, and therefore parasitism facilitates the coexistence of drosophilid species in domestic areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1703.2000.00328.x
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  • 10
    Electronic Resource
    Electronic Resource
    Identification ofDrosophila mutant with memory defects after acquisition of conditioned reflex suppression of courtship (2000)
    Springer
    Neuroscience and behavioral physiology 30 (2000), S. 307-313 
    Details
    ISSN: 1573-899X
    Keywords: Memory ; suppression of courting ; Drosophila ; mutants ; P insertion mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Four lines were selected from a collection of 33 lines prepared by P insertion mutagenesis using a single-copy P-element system; the males of these four lines showed memory defects after acquisition of conditioned reflex suppression of courting. In two lines (P171 and P95), the dynamics of retention of the conditioned reflex in the repeated impregnated-female courting test were similar to those of known short-term memory mutantsdnc andrut. In line P153, the dynamics were more reminiscent of the memory dynamics in a known medium-term memory mutant,amn. In line P124, the learning index was insignificant immediately after training was completed, which may indicate that this line was unable to acquire conditioned reflex suppression of courting. Determination of the positions of the P elements (P171: 48A-B; P153: 49B-C; P124; 67B–68A; P95: 77C-D) showed no correspondence with previously known mutations producing memory lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471783
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  • 11
    Electronic Resource
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    Parental Imprinting in Drosophila (2000)
    Springer
    Genetica 109 (2000), S. 35-44 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; heterochromatin ; imprinting ; parental effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic imprinting is a form of epigenetic silencing. But with a twist. The twist is that while imprinting results in the silencing of genes, chromosome regions or entire chromosome sets, this silencing occurs only after transmission of the imprinted region by one sex of parent. Thus genetic imprinting reflects intertwined levels of epigenetic and developmental modulation of gene expression. Imprinting has been well documented and studied in Drosophila, however, these studies have remained largely unknown due to nothing more significant than differences in terminology. Imprinting in Drosophilais invariably associated with heterochromatin or regions with unusual chromatin structure. The imprint appears to spread from imprinted centers that reside within heterochromatin and these are, seemingly, the only regions that are normally imprinted in Drosophila. This is significant as it implies that while imprinting occurs in Drosophila, it is generally without phenotypic consequence. Hence the evolution of imprinting, at least in Drosophila, is unlikely to be driven by the function of specific imprinted genes. Thus, the study of imprinting in Drosophilahas the potential to illuminate the mechanism and biological function of imprinting, and challenge models based solely on imprinting of mammalian genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026592318341
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  • 12
    Electronic Resource
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    Searching for a Common Centromeric Structural Motif: Drosophila Centromeric Satellite DNAs Show Propensity to form Telomeric-Like Unusual DNA Structures (2000)
    Springer
    Genetica 109 (2000), S. 71-75 
    Details
    ISSN: 1573-6857
    Keywords: centromere ; heterochromatin ; non B-DNA structures ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The molecular basis of centromere formation in a particular chromosomal region is not yet understood. In higher eukaryotes, no specific DNA sequence is required for the assembly of the kinetochore, but similar centromeric chromatins are formed on different centromere DNA sequences. Although epigenesis has been proposed as the main mechanism for centromere specification, DNA recognition must also play a role. Through the analysis of Drosophilacentromeric DNA sequences, we found that dodeca satellite and 18HT satellite are able to form unusual DNA structures similar to those formed by telomeric sequences. These findings suggest the existence of a common centromeric structural DNA motif which we feel merits further investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026546510127
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  • 13
    Electronic Resource
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    Genetic and biochemical analysis of brown eye mutation in Drosophila nasuta nasuta and Drosophila nasuta albomicans (2000)
    Springer
    Genetica 109 (2000), S. 235-243 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; brown eye ; eye pigments ; fitness ; gene localization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By analyzing the progeny of crosses involving brown eye mutants and the wild types in two members of Drosophila nasuta subgroup namely D. n. nasuta and D. n. albomicans we could show that the mutant gene is recessive, located in the chromosome 2 and the alleles of this gene are present at different loci. A study of fitness in the eye color mutants in comparison with the wild types revealed that D. n. nasuta mutant has higher viability at both 25 ± 1°C and ambient temperatures; while D. n. albomicans mutant has faster rate of development only at 25 ± 1°C. Quantitative analysis of eye pigments in the mutants revealed that there is biosynthesis of both pteridines and xanthommatins unlike in bw/bw of D. melanogaster, where only xanthommatins are synthesized. In both the species, the pteridine quantities in mutants are similar; whereas xanthommatin quantity in $$\user1{bw}_n \user1{/bw}_n$$ is 10 times higher than that of $$\user1{bw}_a \user1{/bw}_a$$ . Further, the F1 progeny of intraspecific crosses (wild type X mutant) are found to have high amounts of pteridine, even when compared with parental wild type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017505400086
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  • 14
    Electronic Resource
    Electronic Resource
    Dnop56, a Drosophila gene homologous to the yeast nucleolar NOP56 gene (2000)
    Springer
    Genetica 109 (2000), S. 275-282 
    Details
    ISSN: 1573-6857
    Keywords: DmNop56 ; DsNop56 ; Drosophila ; molecular evolution ; snoRNPs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Small nucleolar RNAs (snoRNAs) are trans‐acting factors involved in maturation of rRNA and have been classified into Box C/D and Box H/ACA families. Most of the snoRNAs occur as ribonucleoprotein complexes with snoRNA‐associated proteins (snoRNPs). All Box C/D snoRNAs in yeast form complexes with Nop1p, Nop56p and Nop58p. Similarly, it has been reported that Box H/ACA‐containing snoRNAs form complexes with yeast Gar1p. Nop56p and Nop58p homologs have been described in several species. Here we report the isolation and molecular characterization of the Dnop56 genes from D. melanogaster and D. subobscura which show a very similar structure. Drosophila Nop56p proteins contain lysine‐rich regions at their carboxy‐terminus, and show a high degree of similarity to other Nop56p proteins from different organisms. Phylogenetic relationships among these proteins and other snoRNPs have been established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017596312331
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  • 15
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    Calmodulin-dependent and -independent apoptosis in cells of a Drosophila neuronal cell line (2000)
    Springer
    Apoptosis 5 (2000), S. 133-140 
    Details
    ISSN: 1573-675X
    Keywords: Apoptosis ; calmodulin ; caspases ; cell line ; Drosophila ; neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study was undertaken to reveal apoptotic pathways in neurons using a Drosophila neuronal cell line derived from larval central nervous system. We could induce apoptotic cell death in the cells by a Ca2+ ionophore (A23187), a protein kinase inhibitor (H-7), an RNA synthesis inhibitor (actinomycin D) and a protein synthesis inhibitor (cycloheximide). All the apoptosis induced by each chemical required Ca2+ ions, although the origin of Ca2+ ions were different: apoptosis induced by A23187 was dependent on extracellular Ca2+ ions whereas those by the other three chemicals utilized intracellular Ca2+ ions. Furthermore, different reactions to W-7, a calmodulin inhibitor, were found: W-7 prevented the cell death by each of the three chemicals but not by A23187. Based on the results, we proposed that the apoptotic pathways are classified into two types in individual cells. One pathway induced by H-7, actinomycin D or cycloheximide is calmodulin-dependent (pathway H), and another induced by A23187 is calmodulin-independent (pathway A).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009676528805
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  • 16
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    An episode of accelerated amino acid change in Drosophila esterase-6 associated with a change in physiological function (2000)
    Springer
    Genetica 110 (2000), S. 231-244 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; , esterase-6 ; function ; sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most lineages of the subgenus Sophophora esterase-6 is a homodimeric haemolymph protein. In the melanogaster subgroup of species it has become a monomer which is mainly expressed in the male sperm ejaculatory duct. Our analyses of esterase-6 sequences from three melanogaster subgroup species and two close relatives reveal a brief period of accelerated amino acid sequence change during the transition between the ancestral and derived states. In this period of 2–6Myr the ratio of replacement to silent site substitutions (0.51) is about three times higher than the values in other lineages of the phylogeny. There are about 50 more replacements in this period than would be predicted from the ratios of replacement to silent site substitutions found elsewhere in the phylogeny. Modelling on the known structure of a related acetylcholinesterase suggests that an unusually high proportion of the replacements in the transitional branch are non-conservative changes on the protein surface. Up to half the accelerated replacement rate can be accounted for by clusters of changes to the face of the molecule containing the opening of the active site gorge. This includes changes in and around regions homologous to peripheral substrate binding sites in acetylcholinesterase. There are also three changes in glycosylation status. One region predicted to lie on the protein surface which becomes markedly more hydrophilic is proposed to be the ancestral dimerisation site that is lost in the transitional branch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012727814167
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  • 17
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    Impact of Multiple Insertions of two Retroelements, ZAM and Idefix at an Euchromatic Locus (2000)
    Springer
    Genetica 109 (2000), S. 53-59 
    Details
    ISSN: 1573-6857
    Keywords: chromatin structure ; Drosophila ; mutagenic effect ; retroelements ; white
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements represent a large fraction of eukaryotic genomes and they are thought to play an important role in chromatin structure. ZAMand Idefixare two LTR-retrotransposons from Drosophila melanogastervery similar in structure to vertebrate retroviruses. In all the strains where their distribution has been studied, ZAMappears to be present exclusively in the intercalary heterochromatin while Idefixcopies are mainly found in the centromeric heterochromatin with very few copies in euchromatin. Their distribution varies in a specific strain called RevI in which the mobilization of ZAMand Idefixis highly induced. In this strain, 15 copies of ZAMand 30 copies of Idefixare found on the chromosomal arms in addition to their usual distribution. Amongst the loci where new copies are detected, a hotspot for their insertion has been detected at the whitelocus where up to four elements occurred within a 3-kb fragment at the 5′ end of this gene. This property of ZAMand Idefixto accumulate at a defined site provides an interesting paradigm to bring insight into the effect exerted by multiple insertions of transposable elements at an euchromatic locus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026534207401
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  • 18
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    Variations of male cuticular hydrocarbons with geoclimatic variables: an adaptative mechanism in Drosophila melanogaster? (2000)
    Springer
    Genetica 110 (2000), S. 117-130 
    Details
    ISSN: 1573-6857
    Keywords: adaptation ; Drosophila ; hydrocarbons ; latitude ; longitude ; natural populations ; polymorphism ; temperaturey ; vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 7-tricosene (7T) and 7-pentacosene (7P) are the major components of cuticular hydrocarbons in Drosophila simulans and D. melanogaster males. A chemical study of 16 isofemale lines of D. melanogaster sampled at the first and eighth generations in laboratory conditions showed the stability of chromatographical profiles. Then a large scale study of male 7T/7P polymorphism was performed with 85 populations of D. melanogaster and 29 of D. simulans collected all over the world. There were significant correlations of the values of the balanced ratio (7T − 7P)/(7T + 7P) with geo-climatic parameters, such as latitude, longitude, mean temperature, temperature range and vapour pressure. Parallel variations were also reported for the homologous linear alkanes (23 and 25 Carbon atoms) but not for the longer branched alkanes (27 and 29 Carbon atoms). No correlation was significant for the D. simulans populations studied. In this species a similar polymorphism of 7T/7P was found but restricted to a few populations from West Equatorial Africa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017987220814
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  • 19
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    Genetic variance in temperature dependent adult size deriving from physiological genetic variation at temperature boundaries (2000)
    Springer
    Genetica 110 (2000), S. 195-207 
    Details
    ISSN: 1573-6857
    Keywords: biophysics ; body size ; Drosophila ; ectotherm ; genetic variance ; stress ; temperature extreme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An increase in genetic variation in body size has often been observed under stress; an increase in dominance variance and interaction variance as well as in additive genetic variance has been reported. The increase in genetic variation must be caused by physiological mechanisms that are specific to adverse environments. A model is proposed to explain the occurrence of an increase in genetic variation in body size in Drosophila at extreme temperatures. The model has parameters specific to the low- and high-temperature regions of the viable range. Additive genetic variation in the boundary temperatures leads to a marked increase in additive genetic variation in development rate and body size at extreme temperatures. Additive genetic variation in the temperature sensitivity in the low- and high-temperature regions adds non-additive genetic variation. Development rate shows patterns in additive genetic variation that differ from the patterns of genetic variation in body size; therefore, the genetic correlation between development rate and body size changes sign repeatedly as a function of temperature. The existence of dominance in the genetic variation in the boundary temperatures or in the low- and high-temperature sensitivities leads to a higher total genetic variance due to higher dominance and interaction variance, for both development rate and body size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017974618477
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    Distinct requirements for the AP-3 adaptor complex in pigment granule and synaptic vesicle biogenesis in Drosophila melanogaster (2000)
    Springer
    Molecular genetics and genomics 263 (2000), S. 1003-1014 
    Details
    ISSN: 1617-4623
    Keywords: Key words AP-3 ; Biogenesis ; Pigment granule ; Synaptic vesicle ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The AP-3 adaptor protein complex has been implicated in the biogenesis of lysosome-related organelles, such as pigment granules/melanosomes, and synaptic vesicles. Here we compare the relative importance of AP-3 in the biogenesis of these organelles in Drosophila melanogaster. We report that the Drosophila pigmentation mutants orange and ruby carry genetic lesions in the σ3 and β3-adaptin subunits of the AP-3 complex, respectively. Electron microscopy reveals dramatic reductions in the numbers of electron-dense pigment granules in the eyes of these AP-3 mutants. Mutant flies also display greatly reduced levels of pigments housed in these granules. In contrast, electron microscopy of retinula cells reveals numerous synaptic vesicles in both AP-3 mutant and wild-type flies, while behavioral assays show apparently normal locomotor ability of AP-3 mutant larvae. Together, these results demonstrate that Drosophila AP-3 is critical for the biogenesis of pigment granules, but is apparently not essential for formation of a major population of synaptic vesicles in vivo.
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    URL: http://dx.doi.org/10.1007/PL00008688
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    Modulation of Paired-Pulse Responses in the Dentate Gyrus: Effects of Normal Maturation and Vigilance State (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 128-134 
    Details
    ISSN: 1573-9686
    Keywords: Hippocampus ; Vigilance states ; Paired-pulse ; Dentate gyrus ; Dentate granule cells ; Evoked response ; Rat ; In vivo studies ; Perforant path ; Maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract This study examined the effect of normal development and vigilance state on the modulation of dentate granule cell activity in the freely moving rat at 15, 30, and 90 days of age across three vigilance states: quiet waking, slow-wave sleep, and rapid eye movement sleep. Using paired-pulse stimulation, the paired-pulse index (PPI) was obtained for the dentate evoked field potentials elicited by the stimulation of the medial perforant path. Although significant differences in PPI values were observed during development, no significant vigilance state related changes were obtained. Preweaning infant rats, i.e., 15-day old, exhibited significantly less early (interpulse intervals, IPI= 20–50 ms) and late (IPI = 300–1000 ms) inhibition, and less facilitation (IPI = 50–150 ms) when compared to the 90-day old adult rats during all three vigilance states. PPI values obtained from the 30-day old group fell intermediate between the 15- and 90-day old animals. These changes in PPI values provide a quantitative measure of changes in the modulation of dentate granule cell excitability during normal maturation. They can now can be used to evaluate the impact of various insults, such as prenatal protein malnutrition or neonatal stress, on hippocampal development. © 2000 Biomedical Engineering Society. PAC00: 8717Nn, 8719La, 8719Nn
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    URL: http://dx.doi.org/10.1114/1.261
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    Left Ventricular Contractility is Impaired Following Myocardial Infarction in the Pig and Rat: Assessment by the End Systolic Pressure–Volume Relation Using a Single-Beat Estimation Technique and Cine Magnetic Resonance Imaging (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 484-494 
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    ISSN: 1573-9686
    Keywords: Heart ; Left ventricle ; LV contractility ; ESPVR ; Pig ; Rat ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The end systolic pressure–volume relation (ESPVR) has been shown to be a relatively load independent measure of left ventricular (LV) contractility. Recently, several single-beat ESPVR computation methods have been developed, enabling the quantification of LV contractility without the need to alter vascular loading conditions on the heart. Using a single-beat ESPVR method, which has been validated previously in humans and assumes that normalized elastance is constant between individuals of a species, we studied the effects of myocardial infarction on LV contractility in two species, the rat and the pig. In our studies, LV pressure was acquired invasively and LV volume determined noninvasively with magnetic resonance imaging, at one week postinfarction in pigs and at 12 weeks postinfarction in rats. Normalized systolic elastance curves in both animal species were not statistically different from that of humans. Also, the slope of the ESPVR $$\left( {E_{es} } \right)$$ decreased significantly following infarction in both species, while the volume-axis intercept $$\left( {V_0 } \right)$$ was unaffected. These results indicate that a single-beat ESPVR method can be used to measure the inotropic response of the heart to myocardial infarction, and that the basis for this method (i.e., constant normalized elastance) is applicable to a variety of mammalian species. © 2000 Biomedical Engineering Society. PAC00: 8719Uv, 8761Lh, 8719Hh, 8719Rr, 8719Ff
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    URL: http://dx.doi.org/10.1114/1.289
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    Quantifying Coevolution of Nonstationary Biomedical Signals Using Time-Varying Phase Spectra (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 1101-1115 
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    ISSN: 1573-9686
    Keywords: Time–frequency analysis ; Coherence ; Cross correlation ; Nonstationary persistent signals ; Central pattern generator ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract We present a novel time-varying phase spectrum (TVPS) method to quantify the dynamics of coevolution of two persistent nonstationary coupled signals. Based on the TVPS, an instantaneous intersignal phase shift is defined within the primary frequency range in which the two signals are highly correlated. The TVPS is estimated using a fixed-window method or an adaptive-window method. In the latter method, the window length changes dynamically and automatically as a function of change in frequency of the signals. The effects of altering window types and lengths on the accuracy of the estimation of the primary phase shift is assessed by analyzing synthesized linear chirp signals with decaying amplitude and constant relative phase shift or decaying amplitude and changing relative phase shifts. The methods developed are also used for determining the evolution of the primary phase shift among ventral root activities during fictive locomotion in an in vitro rat spinal cord preparation. The analyses indicate that the TVPS method in conjunction with the determination of the primary frequency range, allows determination of both the evolution of the coupling strength and the evolution of the phase shift between two persistent nonstationary rhythmic signals in the joint time–frequency domain. An adaptive window reduces the estimation bias and the estimation variability. © 2000 Biomedical Engineering Society. PAC00: 0230-f, 8780Tq
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    URL: http://dx.doi.org/10.1114/1.1313775
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    Control of Telomere Elongation and Telomeric Silencing in Drosophila Melanogaster (2000)
    Springer
    Genetica 109 (2000), S. 61-70 
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    ISSN: 1573-6857
    Keywords: Drosophila ; heterochromatin ; telomere ; transcription ; transposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome length in Drosophilais maintained by the targeted transposition of two families of non-LTR retrotransposons, HeT-Aand TART. Although the rate of transposition to telomeres is sufficient to counterbalance loss from the chromosome ends due to incomplete DNA replication, transposition as a mechanism for elongating chromosome ends raises the possibility of damaged or deleted telomeres, because of its stochastic nature. Recent evidence suggests that HeT-Atransposition is controlled at the levels of transcription and reverse transcription. HeT-Atranscription is found primarily in mitotically active cells, and transcription of a w +reporter gene inserted into the 2L telomere increases when the homologous telomere is partially or completely deleted. The terminal HeT-Aarray may be important as a positive regulator of this activity in cis, and the subterminal satellite appears to be an important negative regulator in cis. A third chromosome modifier has been identified that increases the level of reverse transcriptase activity on a HeT-A RNA template and greatly increases the transposition of HeT-A. Thus, the host appears to play a role in transposition of these elements. Taken together, these results suggest that control of HeT-Atransposition is more complex than previously thought.
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    URL: http://dx.doi.org/10.1023/A:1026548503320
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    Molecular organization of the Drosophila melanogaster Adh chromosomal region in D. replete and D. buzzatii, two distantly related species of the Drosophila subgenus (2000)
    Springer
    Chromosome research 8 (2000), S. 375-385 
    Details
    ISSN: 1573-6849
    Keywords: Adh ; Drosophila ; FISH ; genome evolution ; repleta group
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The molecular organization of a 1.944-Mb chromosomal region of Drosophila melanogaster around the Adh locus has been analyzed in two repleta group species: D. repleta and D. buzzatii. The extensive genetic and molecular information about this region in D. melanogaster makes it a prime choice for comparative studies of genomic organization among distantly related species. A set of 26 P1 phages from D. melanogaster were successfully hybridized using fluorescence in-situ hybridization (FISH) to the salivary gland chromosomes of both repleta group species. The results show that the Adh region is distributed in D. repleta and D. buzzatii over six distant sites of chromosome 3, homologous to chromosomal arm 2L of D. melanogaster (Muller's element B). This observation implies a density of 2.57 fixed breakpoints per Mb in the Adh region and suggests a considerable reorganization of this chromosomal element via the fixation of paracentric inversions. Nevertheless, breakpoint density in the Adh region is three times lower than that estimated for D. repleta chromosome 2, homologous to D. melanogaster 3R (Muller's element E). Differences in the rate of evolution among chromosomal elements are seemingly persistent in the Drosophila genus over long phylogenetic distances.
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    URL: http://dx.doi.org/10.1023/A:1009206702214
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    Distribution of the Transposable Element Minos in the Genus Drosophila (2000)
    Springer
    Genetica 108 (2000), S. 263-267 
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    ISSN: 1573-6857
    Keywords: Drosophila ; horizontal transfer ; Minos ; Tc1-like ; Tc1-marinerfamily ; transposable elements ; transposon distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analyzed 28 species of the genus Drosophilafor the presence of the Tc1-like transposable element Minosusing Southern blot hybridization under high stringency conditions. The Minostransposon was found in members of both the Drosophilaand the Sophophorasubgenus showing a distribution that is wider if compared to other well-studied Drosophilatransposons such as the Pelement, hoboand mariner. The presence of Minos-hybridizing sequences was discontinuous in the Sophophorasubgenus, especially in the melanogasterspecies group. Using the Polymerase Chain Reaction we amplified a portion corresponding to the putative Minostransposase from different Drosophilaspecies. Cloning and sequence analysis of randomly selected Minoscopies from D. mojavensisis, D. saltansand D. willistonisupports the idea that event(s) of horizontal transfer may have contributed to the spreading of this transposon in the Drosophilagenus.
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    URL: http://dx.doi.org/10.1023/A:1004185024017
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    Spatial differences in patterns of modification: selection on hairy in Drosophila melanogaster wings (2000)
    Springer
    Genetica 109 (2000), S. 169-181 
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    ISSN: 1573-6857
    Keywords: artificial selection ; atavistic structures ; Drosophila ; pattern formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Artificial selection was carried out for over 45 generations to enhance and suppress expression of the mutation hairy on the Drosophila melanogaster wing. Whole chromosome mapping of X‐linked and autosomal modifiers of sense organ number displayed regional differences in magnitude and direction of their effects. Regional specificity of modifier effects was also seen in some interchromosomal interactions. Scanning electron microscopy allowed precise measurement of sense organ size and position along the L3 longitudinal wing vein. Sense organ size varied in a predictable fashion along the proximal–distal axis, and the dorsal pattern differed from the ventral pattern. The high and low selection lines differed most in the proximal portion of the L3 vein. Extra sense organs in the High line were often associated with vein fragments at locations predicted from ancestral vein patterns. Thus, regional specificity of polygenic or quantitative trait locus modifier effects was identified in several different parts of the wing.
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    URL: http://dx.doi.org/10.1023/A:1017531404454
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    Genetic analysis of extended lifespan in Drosophila melanogaster III. On the relationship between artificially selected and wild stocks (2000)
    Springer
    Genetica 109 (2000), S. 245-253 
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    ISSN: 1573-6857
    Keywords: artificial selection ; Drosophila ; lifespan ; mortality ; paraquat ; DDT ; recovery hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult lifespans, age‐specific survival, age‐specific mortality, survival times on paraquat, and survival times on DDT were assayed in seven lines of Drosophila melanogaster, including two genetically heterogeneous wild lines recently collected from nature, and three inbred and recombinant inbred lines derived from an artificial selection experiment for increased lifespan. Survival on paraquat is positively correlated with adult lifespan. DDT resistance is uncorrelated with either paraquat resistance or lifespan. The wild lines are unexceptional with respect to average lifespan, paraquat resistance, age‐specific survivorship, and leveling off of mortality rates at advanced ages, but have high levels of DDT resistance. Cluster analysis groups the wild lines with three unselected laboratory stocks in one cluster, while two long‐lived elite recombinant inbred lines form a second cluster. Long‐lived laboratory‐adapted lines are quantitatively differentiated from the wild stocks, both with respect to average adult lifespans and resistance to an oxidizing agent. We reject the ‘recovery’ hypothesis, which proposes that Drosophila artificially selected for long life have phenotypes that merely recover the wild state.
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    URL: http://dx.doi.org/10.1023/A:1017569318401
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    Role of AWD/Nucleoside Diphosphate Kinase in Drosophila Development (2000)
    Springer
    Journal of bioenergetics and biomembranes 32 (2000), S. 293-300 
    Details
    ISSN: 1573-6881
    Keywords: abnormal wing discs ; lethal mutant ; Drosophila ; Killer-of-prune ; prune
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The abnormal wing discs gene of Drosophila encodes a soluble protein with nucleosidediphosphate kinase activity. This enzymic activity is necessary for the biological function ofthe abnormal wing discs gene product. Complete loss of function, i.e., null, mutations causelethality after the larval stage. Most larval organs in such null mutant larvae appear to benormal, but the imaginal discs are small and incapable of normal differentiation.Killer-of-prune is a neomorphic mutation in the abnormal wing discs gene. It causes dominant lethalityin larvae that lack prune gene activity. The Killer-of-prune mutant protein may have alteredsubstrate specificity. Null mutant larvae have a low level of nucleoside diphosphate kinaseactivity. This suggests that there may be additional Drosophila genes that encode proteinswith nucleoside dipthosphate kinase activity. Candidate genes have been found in theDrosophila genome.
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    URL: http://dx.doi.org/10.1023/A:1005545214937
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    Common Mechanisms of Y Chromosome Evolution (2000)
    Springer
    Genetica 109 (2000), S. 105-111 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; heterochromatin ; Y chromosome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome evolution is characterized by the expansion of genetic inertness along the Y chromosome and changes in the chromosome structure, especially the tendency of becoming heterochromatic. It is generally assumed that the sex chromosome pair has developed from a pair of homologues. In an evolutionary process the proto-Y-chromosome, with a very short differential segment, develops in its final stage into a completely heterochromatic and to a great extends genetically eroded Y chromosome. The constraints evolving the Y chromosome have been the objects of speculation since the discovery of sex chromosomes. Several models have been suggested. We use the exceptional situation of the in Drosophila mirandato analyze the molecular process in progress involved in Y chromosome evolution. We suggest that the first steps in the switch from a euchromatic proto-Y-chromosome into a completely heterochromatic Y chromosome are driven by the accumulation of transposable elements, especially retrotransposons inserted along the evolving nonrecombining part of the Y chromosome. In this evolutionary process trapping and accumulation of retrotransposons on the proto-Y-chromosome should lead to conformational changes that are responsible for successive silencing of euchromatic genes, both intact or already mutated ones and eventually transform functionally euchromatic domains into genetically inert heterochromatin. Accumulation of further mutations, deletions, and duplications followed by the evolution and expansion of tandem repetitive sequence motifs of high copy number (satellite sequences) together with a few vital genes for male fertility will then represent the final state of the degenerated Y chromosome.
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    URL: http://dx.doi.org/10.1023/A:1026584016524
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    Versatility of Conviction: Heterochromatin as Both a Repressor and an Activator of Transcription (2000)
    Springer
    Genetica 109 (2000), S. 19-24 
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    ISSN: 1573-6857
    Keywords: chromosomal proteins ; Drosophila ; heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026544717126
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    Drosophila Telomeric Transgenes Provide Insights on Mechanisms of Gene Silencing (2000)
    Springer
    Genetica 109 (2000), S. 25-33 
    Details
    ISSN: 1573-6857
    Keywords: chromatin ; Drosophila ; heterochromatin ; position effect variegation ; telomeres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A significant fraction of most eukaryotic genomes is packaged into chromatin that is not permissive for gene expression. This silent chromatin is typically located near centromeres and telomeres and has fascinated scientists for more than 70 years, yet many questions remain unanswered. Part of the difficulties in studying silent chromatin at the molecular level is the repetitive nature of the DNA sequences in these regions. To overcome this problem, Drosophilastocks carrying in vitrodesigned transgenes inserted within silent chromatin have been generated. Molecular analysis of these transgenes has shed light on the nature of the chromatin structure within these regions and provided insights on the mechanisms of gene silencing. This review will focus on recent studies using telomeric transgenes. The results from these studies suggest that nuclear organization plays a role in gene silencing and that silencing is the result of a block early in the process of transcription initiation.
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    Isolation of True Rbp9 Null Alleles by Imprecise P Element Excisions (2000)
    Springer
    Molecules and cells 10 (2000), S. 61-64 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Imprecise Excision ; Null Allele ; P Element ; Rbp9
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The P element has been widely used as a mutagen because of its convenience in locating the site of mutagenesis. However, P element-induced mutations often result in varied mutant phenotypes, making it difficult to identify the null phenotype. Previously, three Rbp9 alleles were isolated using P element mutagenesis. Although the coding regions of Rbp9 were disrupted by P elements in all three cases, they showed different degrees of defects. In order to characterize the null phenotype of Rbp9, Rbp9 alleles with chromosomal deletions were created by inducing imprecise excisions of the P elements. All Rbp9 alleles generated from imprecise excisions showed the same mutant phenotype: female flies were sterile and cystocyte differentiation was blocked. This result reveals that the primary function of Rbp9 resides in the regulation of cystocyte differentiation. In addition, this result shows that a P element does not always completely inactivate gene activity, even when it is incorporated into the coding region.
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    Effects of Polycomb Group Mutations on the Expression of Ultrabithorax in the Drosophila Visceral Mesoderm (2000)
    Springer
    Molecules and cells 10 (2000), S. 156-161 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Polycomb Group Genes ; Ultrabithorax ; Visceral Mesoderm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Polycomb group (PcG) genes encode repressors of many developmental regulatory genes including homeotic genes and are known to act by modifying chromatin structure through complex formation. We describe how Ultrabithorax (Ubx) expression is affected by the PcG mutants in the visceral mesoderm. Mutant embryos of the genes extra sex combs (esc), Polycomb (Pc), additional sex combs (Asx) and pleiohomeotic (pho) were examined. In each mutation, Ubx was ectopically expressed outside of their normal domains along the anterior-posterior axis in the visceral mesoderm, which is consistent with the effect of PcG proteins repressing the homeotic genes in other tissues. All of these four PcG mutations exhibit complete or partial lack of midgut constriction. However, two thirds of esc mutant embryos did not show Ubx expression in parasegment 7 (PS7). Even in the embryos showing ectopic Ubx expression, the level of Ubx expression in the PcG mutations was weaker than that in normal embryos. We suggest that in PcG mutations the ectopic Ubx expression is caused by lack of PcG repressor proteins, while the weaker or lack of Ubx expression is due to the repression of Ubx by Abd-B protein which is ectopically expressed in PcG mutations as well.
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    Regulation of Mst57Dc Expression in Male Accessory Glands of Dorsophila melanogaster (2000)
    Springer
    Molecules and cells 10 (2000), S. 180-185 
    Details
    ISSN: 0219-1032
    Keywords: Drosophila ; Gene Expression ; JHRE ; Juvenile Hormone ; Male Accessory Gland ; Mst57Dc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mst57Dc has been isolated as a male accessory gland transcript of Drosophila melanogaster. Its product is a secretory protein, which is phosphorylated by protein kinase A. In the present study, the expression pattern of Mst57Dc was analyzed. It is preferentially expressed in but not restricted to the male accessory glands. Other than in the accessory glands, it is slightly expressed in other body parts, including the head and female body. In the accessory glands, a high level of expression was detected right after eclosion when the titer of juvenile hormone III (JHIII) reaches a peak. Its accumulation was increased by mating, which has been known to act via JH. In ap56f, a JH-deficient mutant, the level of Mst57Dc transcripts was about 60% of the wild type. Moreover a JH-responsive element like palindromic sequence and several sequence motifs were found in the 5′ and 3′ flanking regions of Mst57Dc. Taken together, JH is proposed as a regulator of Mst57Dc gene expression.
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    c-Fos Expression by Dopaminergic Receptor Activation in Rat Hippocampal Neurons (2000)
    Springer
    Molecules and cells 10 (2000), S. 546-551 
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    ISSN: 0219-1032
    Keywords: c-Fos ; Dopamine ; D1 ; Hippocampus ; Rat ; Synaptic Plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract While dopamine is likely to modulate hippocampal synaptic plasticity, there has been little information about how dopamine affects synaptic transmission in the hippocampus. The expression of IEGs including c-fos has been associated with late phase LTP in the CA1 region of the hippocampus. The induction of c-fos by dopaminergic receptor activation in the rat hippocampus was investigated by using semiquantitative RT-PCR and immuno-cytochemistry. The hippocampal slices which were not treated with dopamine showed little expression of c-fos mRNA. However, the induction of c-fos mRNA was detected as early as 5 min after dopamine treatment, peaked at 60 min, and remained elevated 5 h after treatment. Temporal profiles of increases in c-fos mRNA by R(+)-SKF-38393 (50 μM) and forskolin (50 μM) were similar to that of dopamine. An increase in [cAMP] was observed in dopamine-, SKF-, or forskolin-treated hippocampal slices. By immunocytochemical studies, control hippocampal cells showed little expression of c-Fos immunoreactivity. However, when cells were treated with dopamine, an increase in the expression of c-Fos immunoreactivity was observed after treatment for 2 h. The treatment of hippocampal neurons with R(+)-SKF38393 (50 μM) or forskolin (50 μM) also induced a significant increase in c-Fos expression. These results indicate that the dopamine D1 receptor-mediated cAMP dependant pathway is associated with the expression of c-Fos in the hippocampal neurons. These data are consistent with the possible role of endogenous dopamine on synaptic plasticity via the regulation of gene expression. Furthermore, these results imply that dopamine might control the process of memory storage in the hippocampus through gene expression.
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    URL: http://dx.doi.org/10.1007/s10059-000-0546-y
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    Behavioral Characterization and Genetic Analysis of the Drosophila melanogaster Larval Response to Light as Revealed by a Novel Individual Assay (2000)
    Springer
    Behavior genetics 30 (2000), S. 59-69 
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    ISSN: 1573-3297
    Keywords: Insect ; larval photobehavior ; locomotion ; Drosophila ; behavioral mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract A new assay was designed, named checker, that measures the individual response to light in the fruitfly Drosophila melanogaster larva. In this assay the Drosophila larva apparently modulates its pattern of locomotion when faced with a choice between a dark and lit environment by orienting its movement towards the dark environment. We show that, in this assay, a response to light can be measured as an increase in residence time in the dark versus the lit quadrant. Mutations that disrupt phototransduction in the adult Drosophila abolish the larval response to light, demonstrating that this larval visual function is similar to that of the adult fly. Similarly, no response to light was detected in strains where the larval visual system (photoreceptors and target area) was disrupted by a mutation in the homeobox containing gene sine oculis (so) gene. Ablation of photoreceptors by the targeted expression of the cell death gene hid under the control of the photoreceptor-specific transcription factor glass (gl) abolishes this response entirely. Finally, we demonstrate that this response to light can be mediated by rhodopsins other than the blue absorbing Rh1.
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    Detection and analysis of gastrointestinal sounds in normal and small bowel obstructed rats (2000)
    Springer
    Medical & biological engineering & computing 38 (2000), S. 42-48 
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    ISSN: 1741-0444
    Keywords: Bowel sounds ; Rat ; Motility ; Body acoustics ; Signal detection ; Signal characterisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This study is aimed at detecting gastrointestinal sounds (GIS) and correlating their characteristics with gastrointestinal (GI) conditions. The central hypotheses are that GIS generation depends on the motility patterns and the mechanical properties of the gut, and that changes in those result in measurable differences in GIS. An animal model which included both healthy rats and those with small bowel obstruction (SBO) was developed. The acoustic bursts, of GIS were detected by amplitude thresholding the signal envelope. Three methods of envelope estimation were proposed and evaluated. Envelope estimation using a Hilbert transform was found to produce the best results in the current application. The duration and dominant frequency of each detected GIS event was estimated and clear differences between healthy and diseased rats were discovered. In the control state, GIS events were found to consistently be of relatively short duration (3–65ms). Although the majority of events in the SBO state had similar short duration, infrequent longer events were also detected and appeared to be pathognomonic. Long duration events (〉100 ms) occurred in each of seven obstructed, but in none of 14 non-obstructed, cases (p〈0.001). It is concluded that GIS analysis may prove useful in the non-invasive, rapid, and accurate diagnosis of SBO.
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    URL: http://dx.doi.org/10.1007/BF02344687
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    Pre-exposure affects the olfactory response of Drosophila melanogaster to menthol (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 175-181 
    Details
    ISSN: 1570-7458
    Keywords: Olfactory response ; Drosophila ; menthol ; bioassay ; trap assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A modification of the trap assay (Woodard et al., 1989) was used to evaluate the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose-response curves for flies to mentholic foods were produced for flies that had been pre-exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Mentholic food media were less attractive to Drosophila than plain food medium. Rearing flies on a medium containing menthol reduced their aversion to some concentrations of menthol. The rearing effect was not simply due to lowered general activity levels resulting from developing in a medium containing menthol. There was a threshold concentration of menthol in the rearing medium below which we found no induced behavioural change.
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    URL: http://dx.doi.org/10.1023/A:1003509802181
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    Distinct expression patterns of different Enhancer of split bHLH genes during embryogenesis of Drosophila melanogaster (1999)
    Springer
    Development genes and evolution 209 (1999), S. 370-375 
    Details
    ISSN: 1432-041X
    Keywords: Key words bHLH genes ; Drosophila ; Embryogenesis ; Enhancer of split ; Notch pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  E(spl) bHLH genes are targets of the Notch pathway: they are transcriptionally activated in response to the Notch signal. Yet, during imaginal development, additional regulatory factors appear to modulate transcription resulting in different expression patterns. During early embryogenesis all E(spl) bHLH genes are expressed in roughly the same domain, namely the neurogenic ectoderm. Within this region these seven genes show a highly dynamic, yet distinct transcriptional activity. Our analysis further detected tissue specific expression of some E(spl) genes at later embryonic stages. Prominent differences were observed in the dorsolateral and procephalic neuroectodermal regions as well as in the mesoderm. These observations indicate that other factors in addition to the Notch signal participate in the regulation of the individual E(spl) genes not only in imaginal tissues but also during neuroblast specification and other cell fate determination events in the embryo.
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    URL: http://dx.doi.org/10.1007/s004270050266
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    Role of Notch pathway in terminal follicle cell differentiation during Drosophila oogenesis (1999)
    Springer
    Development genes and evolution 209 (1999), S. 301-311 
    Details
    ISSN: 1432-041X
    Keywords: Key words Delta ; Notch ; Follicle cells ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During Drosophila oogenesis the body axes are determined by signaling between the oocyte and the somatic follicle cells that surround the egg chamber. A key event in the establishment of oocyte anterior-posterior polarity is the differential patterning of the follicle cell epithelium along the anterior-posterior axis. Both the Notch and epithelial growth factor (EGF) receptor pathways are required for this patterning. To understand how these pathways act in the process we have analyzed markers for anterior and posterior follicle cells accompanying constitutive activation of the EGF receptor, loss of Notch function, and ectopic expression of Delta. We find that a constitutively active EGF receptor can induce posterior fate in anterior but not in lateral follicle cells, showing that the EGF receptor pathway can act only on predetermined terminal cells. Furthermore, Notch function is required at both termini for appropriate expression of anterior and posterior markers, while loss of both the EGF receptor and Notch pathways mimic the Notch loss-of-function phenotype. Ectopic expression of the Notch ligand, Delta, disturbs EGF receptor dependent posterior follicle cell differentiation and anterior-posterior polarity of the oocyte. Our data are consistent with a model in which the Notch pathway is required for early follicle cell differentiation at both termini, but is then repressed at the posterior for proper determination of the posterior follicle cells by the EGF receptor pathway.
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    URL: http://dx.doi.org/10.1007/s004270050256
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    Neural expression of hikaru genki protein during embryonic and larval development of Drosophila melanogaster (1999)
    Springer
    Development genes and evolution 209 (1999), S. 1-9 
    Details
    ISSN: 1432-041X
    Keywords: Key words Synapse ; Drosophila ; Immunoglobulin superfamily ; Axonal transport ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Hikaru genki (HIG) is a putative secreted protein of Drosophila that belongs to immunoglobulin and complement-binding protein superfamilies. Previous studies reported that, during pupal and adult stages, HIG protein is synthesized in subsets of neurons and appears to be secreted to the synaptic clefts of neuron-neuron synapses in the central nervous system (CNS). Here we report the analyses of distribution patterns of HIG protein at embryonic and larval stages. In embryos, HIG was mainly observed in subsets of neurons of the CNS that include pCC interneurons and RP5 motorneurons. At third instar larval stage, this protein was detected in a limited number of cells in the brain and ventral nerve cord. Among them are the motorneurons that extend their axons to make neuromuscular junctions on body wall muscle 8. Immunoelectron microscopy showed that these axonal processes as well as the neuromuscular terminals contain numerous vesicles with HIG staining, suggesting that HIG is in a pathway of secretion at this stage. Some neurosecretory cells were also found to express this protein. These data suggest that HIG functions in the nervous system through most developmental stages and may serve as a secreted signalling molecule to modulate the property of synapses or the physiology of the postsynaptic cells.
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    URL: http://dx.doi.org/10.1007/s004270050221
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    Dynamic features of adherens junctions during Drosophila embryonic epithelial morphogenesis revealed by a Dα-catenin-GFP fusion protein (1999)
    Springer
    Development genes and evolution 209 (1999), S. 218-225 
    Details
    ISSN: 1432-041X
    Keywords: Key words α-catenin ; Drosophila ; Green fluorescent protein (GFP) ; Adherens junction ; Epithelial morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cell-cell adherens junctions (AJs), comprised of the cadherin-catenin adhesion system, contribute to cell shape changes and cell movements in epithelial morphogenesis. However, little is known about the dynamic features of AJs in cells of the developing embryo. In this study, we constructed Dα-catenin fused with a green fluorescent protein (Dα-catenin-GFP), and found that it targeted apically located AJ-based contacts but not other lateral contacts in epithelial cells of living Drosophila embryos. Using time-lapse fluorescence microscopy, we examined the dynamic performance of AJs containing Dα-catenin-GFP in epithelial morphogenetic movements. In the ventral ectoderm of stage 11 embryos, concentration and deconcentration of Dα-catenin-GFP occurred concomitantly with changes in length of AJ contacts. In the lateral ectoderm of embryos at the same stage, dynamic behaviour of AJs was concerted with division and delamination of sensory organ precursor (SOP) cells. Moreover, changes in patterns of AJ networks during tracheal extension could be followed. Finally, we utilized Dα-catenin-GFP to precisely observe the defects in tracheal fusion in shotgun mutants. Thus, the Dα-catenin-GFP fusion protein is a helpful tool to simultaneously observe morphogenetic movements and AJ dynamics at high spatio-temporal resolution.
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    URL: http://dx.doi.org/10.1007/s004270050246
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    Characterization of the Tribolium Deformed ortholog and its ability to directly regulate Deformed target genes in the rescue of a Drosophila Deformed null mutant (1999)
    Springer
    Development genes and evolution 209 (1999), S. 389-398 
    Details
    ISSN: 1432-041X
    Keywords: Key words Deformed ; Drosophila ; Embryogenesis ; Tribolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have analyzed the Tribolium castaneum ortholog of the Drosophila homeotic gene Deformed (Dfd) and determined its expression pattern during embryogenesis in this beetle. Tc Deformed (Tc Dfd) is expressed in the blastoderm and the condensing germ rudiment in a region that gives rise to gnathal segments. During germ band extension Tc Dfd is expressed in the mandibular and maxillary segments, their appendages, and the dorsal ridge. Comparison of insect Dfd protein sequences reveals several highly conserved regions. To determine whether common molecular features reflect conserved regulatory functions we used the Gal4 system to express the Tribolium protein in Drosophila embryos. When Tc Dfd is expressed throughout embryonic ectoderm under the control of P69B, the beetle protein autoregulates the endogenous Dfd gene. In addition, the Drosophila proboscipedia gene (a normal target of Dfd) is ectopically activated in the antennal and thoracic segments. We also compared the ability of the beetle and fly proteins to rescue defects in Dfd – mutants by expressing each throughout the embryonic during embryogenesis. Both proteins rescued Dfd – defects to the same extent in that they each restore the development of mouth hooks and cirri, as well as cause gain-of-function abnormalities of posterior mouth parts. As before, pb was ectopically activated in the antennal segment. This is the first demonstration of the ability of a heterologous homeotic selector protein to directly regulate a target gene independent of an endogenous Drosophila autoregulatory loop.
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    URL: http://dx.doi.org/10.1007/s004270050269
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    Nucleotide sequences of three distinct complementary DNA clones encoding rat class II major histocompatibility complex RT1.D β-chain proteins (1999)
    Springer
    Immunogenetics 49 (1999), S. 735-737 
    Details
    ISSN: 1432-1211
    Keywords: Key words Class II MHC sequence ; Rat ; Cloning ; RT-PCR ; Polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1007/s002510050676
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    Structure and functions of arthropod proteasomes (1999)
    Springer
    Molecular biology reports 26 (1999), S. 103-111 
    Details
    ISSN: 1573-4978
    Keywords: arthropod ; crustacean ; Drosophila ; insect ; lobster ; multicatalyic proteinase ; proteasome ; ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work on structural/functional relationships in arthropod proteasomes is reviewed. Taking advantage of our ability to induce a stable, proteolytically-active conformation of the lobster proteasome, the structures of basal and heat-activated complexes were probed with exogenous proteases. Increased sensitivity to chymotrypsin and trypsin showed that heat activation induced a more ‘open’ conformation, allowing entry of large substrates into the catalytic chamber. In Drosophila, the effects of two developmental mutant alleles (DTS-7 and DTS-5) encoding proteasome subunits (Z and C5, respectively) on the subunit composition and catalytic activities of the enzyme were examined. Both qualitative and quantitative differences in compositions between wild-type (+/+) and heterozygotes (+/DTS) indicated that incorporation of mutant subunits alters post-translational modifications of the complex. Catalytic activities, however, were similar, which suggests that the developmental defect involves other proteasome properties, such as intracellular localization and/or interactions with endogenous regulators. A hypothetical model in which DTS subunits act as poison subunits is presented.
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    URL: http://dx.doi.org/10.1023/A:1006976524916
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    Response of Djun and Dfos mRNA abundance to signal transduction pathways in cultured cells of Drosophila melanogaster (1999)
    Springer
    Molecular biology reports 26 (1999), S. 147-157 
    Details
    ISSN: 1573-4978
    Keywords: Drosophila ; jun ; fos ; AP-1 ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mammalian proto-oncogenes c-jun and c-fos are situated at the end of multiple signal transduction pathways and activation of their products Jun and Fos, components of the transcription factor AP-1, are able to regulate gene transcription in response to extracellular stimuli. Djun and Dfos, the products of the Drosophila proto-oncongenes Djun and Dfos, are similar in size and sequence to their mammalian counterparts c-Jun and c-Fos and are related to their mammalian counterparts by their antigenic properties. However, very little is known about how they are regulated through signal transduction pathways. This paper has investigated the response of their mRNA abundance levels to three signal transduction pathways in Drosophila cultured cells. Various agonists and anagonists that stimulate and inhibit specific enzymes in the pathways have been tested. The results suggest that Djun and Dfos mRNA are continuously expressed and their abundance levels are transiently regulated by multiple signaling pathways, the peak response coming at 1–2 hours after perturbation. Dfos is more highly regulated than Djun which is only modulated. The receptor tyrosine kinase pathways positively regulate Dfos and Djun. The cAMP-mediated pathway positively regulates Dfos but negatively regulates Djun. The protein kinase C-activated pathway does not affect Djun whereas it negatively regulates Dfos.
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    URL: http://dx.doi.org/10.1023/A:1006906419110
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    Cytokine-induced conversion of mesencephalic-derived progenitor cells into dopamine neurons (1999)
    Springer
    Cell & tissue research 296 (1999), S. 235-246 
    Details
    ISSN: 1432-0878
    Keywords: Key words Transplantation ; Parkinson’s disease ; CNS fetal development ; CNS differentiation ; Neurotrophic factors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have previously shown that a combination of the cytokines interleukin (IL)-1, IL-11, leukemia inhibitory factor (LIF), and glial cell line-derived neurotrophic factor (GDNF) can convert rat fetal (E14.5) mesencephalic progenitor cells into tyrosine hydroxylase (TH)-immunoreactive (ir) neurons in vitro. The experiments described here characterize the mesencephalic progenitor cells and their cytokine-induced conversion into dopamine (DA) neurons. For all experiments, we used bromodeoxyuridine (BrdU)-ir cultures of (E14.5) mesencephalic progenitor cells that had been expanded at least 21 days. We first demonstrated that IL-1 induced DA neuron conversion in mesencephalic progenitors, but not in striatal progenitors (P〈0.001). Thus, these cells should be classified as lineage-restricted progenitors, and not omnipotent stem cells. To further characterize cell populations in these cultures, we used monoclonal antibodies against Hu (an early marker for neurons), growth-associated protein (GAP)-43 (a marker for neuronal process extension), TH (a marker for DA neurons), and glial fibrillary acidic protein (GFAP, a marker for astrocytes). We assessed (E14.5) mesencephalic progenitor cell cultures (plated at 125,000 cells/cm2) incubated in the cytokine mixture (described above) or in complete media (CM, negative control). Following 7 days incubation, GFAP-positive cells formed a nearly confluent carpet in both types of cultures. However, numbers of Hu-ir and GAP-43-ir cells in the cytokine-incubated cultures far exceeded those in CM-incubated controls (P=0.0003, P=0.0001, respectively), while numbers of TH-ir cells were 58-fold greater in the cytokine-incubated cultures versus CM-incubated controls. The TH phenotype persisted for 7 days following withdrawal of the differentiation media. Numerous double-labeled cells that were BrdU-ir and also TH-ir, or Hu-ir and also TH-ir, were observed in the cytokine-incubated cultures. These data suggest that cytokines ”drive” the conversion of progenitor cells into DA neurons.
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    URL: http://dx.doi.org/10.1007/s004410051285
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    Isograft and xenograft of the subcommissural organ into the lateral ventricle of the rat and the formation of Reissner’s fiber (1999)
    Springer
    Cell & tissue research 296 (1999), S. 457-469 
    Details
    ISSN: 1432-0878
    Keywords: Key words Subcommissural organ ; Isograft ; Xenograft ; Reissner’s fiber ; Cerebrospinal fluid ; Rat ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The subcommissural organ (SCO) secretes glycoproteins into the cerebrospinal fluid (CSF) that aggregate and form Reissner’s fiber (RF). The factors involved in this aggregation are not known. One factor may be the hydrodynamics of the CSF when flowing through the aqueduct. This hypothesis was tested by isografting rat SCO and xenografting bovine SCO into the lateral ventricle of rats. Xenografts were either fresh bovine SCO or explants cultured for 30 days before transplantation. The grafts were investigated by electron microscopy and immunocytochemistry using antibodies against RF glycoproteins, serotonin and the glucose transporter I. Maximal time of transplantation was 43 days for isografts and 14 days for xenografts. The isografts were not reinnervated but were revascularized; they secreted into the ventricle RF glycoproteins that became progressively packed into pre-RF and RF structures identical to those formed by the SCO in situ. RF was confined to the host ventricle and at its distal end the constituent proteins disassembled. Xenografts were neither reinnervated nor revascularized and secreted into the host ventricle a material that never formed an RF. These findings indicate that the CSF factor responsible for the formation of RF is species specific, and that this process does not depend on the hydrodynamics of the CSF. The blood vessels revascularizing the isografted SCO acquired the characteristics of the vessels irrigating the SCO in situ, namely, a tight endothelium displaying glucose transporter I, and a perivascular space containing long-spacing collagen, thus indicating that basal release of glycoproteins may also occur in the grafted SCO.
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    Axonal and dendritic transport in Purkinje cells of cerebellar slice cultures studied by microinjection of horseradish peroxidase (1999)
    Springer
    Cell & tissue research 295 (1999), S. 55-64 
    Details
    ISSN: 1432-0878
    Keywords: Key words Axonal transport ; Purkinje cell ; Organotypic culture ; Microinjection ; Antimitotic drugs ; Cytoskeleton ; Dendritic transport ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Axonal and dendritic transport in single Purkinje neurons of cerebellar slice cultures was quantified as single transport distances. Examination of the cells within a vital tissue was regarded as being an approach to the in situ condition. The Purkinje cells were organotypically integrated in the in vitro tissues and extended long axonal projections connecting synapses to the target neurons. The tracer horseradish peroxidase (HRP) was applied via microinjection to the somata of the Purkinje cells and the injected neurons were incubated thereafter for defined time-intervals. The tracer was transported anterogradely into the neuron processes. The measurements on both the axonal and the dendritic transport of microinjected HRP revealed continuous transportation with increasing times of postincubation. This transport was reduced by the use of microtubule-depolymerizing drugs. The axonal transport of the tracer was either retarded in colchicine-treated cells or continuously reduced for up to 50% in vinblastine-treated neurons. Thus, a correlation of axonal transport to the microtubules was demonstrated. The dendrites were filled with the tracer after 60 min of postincubation. Dendritic transport was reduced by the use of vinblastine, and not significantly by colchicine. The results strongly support the dependence of neuronal transport on microtubules as a component of the cytoskeleton.
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    Cellular and subcellular distribution of the calcium-binding protein NCS-1 in the central nervous system of the rat (1999)
    Springer
    Cell & tissue research 295 (1999), S. 395-407 
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    ISSN: 1432-0878
    Keywords: Key words Neurofilament ; Basket cell ; Pinceau ; Golgi apparatus ; Calcium binding protein ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract NCS-1 (neuronal calcium sensor) is a recently characterized member of a highly conserved neuron-specific family of calcium-binding proteins, which also includes frequenin and recoverin. The cellular and subcellular distributions of NCS-1 in the rat nervous system were investigated using light- and electron-microscopic immunohistochemistry. NCS-1 immunoreactivity was localized to neuronal cell bodies and axons throughout the brain and spinal cord but not to glial cells. The most intense labeling was observed in myelinated axons, the axonal ramifications of the basket cell in the cerebellar cortex, and large neurons in the brainstem and pons. These same structures were also characterized by heavy labeling for neurofilament protein, as determined by double-labeling experiments. Most axon terminals were unlabeled or only lightly labeled. The most remarkable subcellular staining occurred in the perikarya where intense labeling was associated with the membranes of the trans saccules of the Golgi apparatus. The widespread distribution of NCS-1 indicates that it may be active in a variety of calcium-dependent neuronal functions, whereas the specific subcellular localization to the Golgi apparatus and neurofilament-rich structures suggests a specialized role in calcium regulated protein trafficking and cytoskeletal interactions.
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    Expression of neurotrophins, GDNF, and their receptors in rat thyroid tissue (1999)
    Springer
    Cell & tissue research 295 (1999), S. 467-475 
    Details
    ISSN: 1432-0878
    Keywords: Key words Glial cell line-derived neurotrophic factor ; GDNF ; Ret ; GDNFR-α ; Brain-derived neurotrophic factor ; BDNF ; NT-3 ; NT-4 ; trk receptors ; Thyroid tissue ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Levels of mRNA for neurotrophins (brain-derived neurotrophic factor, BDNF; neurotrophin 3, NT-3; neurotrophin 4, NT-4) and their receptors (trkA, trkB, trkC) and for glial cell line-derived neurotrophic factor (GDNF) and its receptors (ret, GDNFR-α) were measured in rat thyroid tissue by ribonuclease protection assays. In thyroid tissue the NT-3 mRNA level was threefold lower and the NT-4 mRNA level sixfold higher than those detected in adult rat hippocampus, while BDNF mRNA was undetectable. Very low levels of mRNA for truncated trkB and trkC receptors and no catalytic trkA, trkB or trkC were found. In conclusion NT-3 and NT-4, but not the corresponding functional receptors, are expressed in the thyroid tissue. Therefore, it is unlikely that these factors serve a direct local autocrine or paracrine function in thyroid cell types, and a target-derived mode of action on neurons innervating the thyroid tissue is suggested. An opposite result has been found for the neurotrophic factor GDNF: thyroid tissue showed a high level of transcripts for the GDNF receptor subunits (GDNFR-α and Ret), while GDNF mRNA was undetectable. The in situ hybridization analysis of GDNFR-α and ret mRNA revealed an interesting difference in the cell distribution of these transcripts: ret mRNA is selectively expressed in a subpopulation of cells scattered in the follicular epithelium and in the interfollicular spaces, while GDNFR-α expression is more homogeneous and widespread, including the more abundant cell type of the thyroid gland: the follicular cell. Double-labeling in situ hybridization/immunocytochemistry experiments, with a specific marker (calcitonin), showed that parafollicular cells express ret but not GDNFR-α. This differential distribution of the GDNF receptor components (GDNFR-α and ret) may reflect a peculiar biological role in intercellular communication in the thyroid gland.
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    Aquaporin-5 (AQP5), a water channel protein, in the rat salivary and lacrimal glands: immunolocalization and effect of secretory stimulation (1999)
    Springer
    Cell & tissue research 295 (1999), S. 513-521 
    Details
    ISSN: 1432-0878
    Keywords: Key words Water channel protein ; Aquaporin ; AQP5 ; Rat ; Salivary glands ; Immunolocalization ; Secretory stimulation ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Aquaporin-5 (AQP5) is a water channel protein and is considered to play an important role in water movement across the plasma membrane. We raised anti-AQP5 antibody and examined the localization of AQP5 protein in rat salivary and lacrimal glands by immunofluorescence microscopy. AQP5 was found in secretory acinar cells of submandibular, parotid, and sublingual glands, where it was restricted to apical membranes including intercellular secretory canaliculi. In the submandibular gland, abundant AQP5 was also found additionally at the apical membrane of intercalated duct cells. Upon stimulation by isoproterenol, apical staining for AQP5 in parotid acinar cells tended to appear as clusters of dots. These results suggest that AQP5 is one of the candidate molecules responsible for the water movement in the salivary glands.
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    The Drosophila cinnamon gene is functionally homologous to Arabidopsis cnx1 and has a similar expression pattern to the mammalian gephyrin gene (1999)
    Springer
    Molecular genetics and genomics 261 (1999), S. 672-680 
    Details
    ISSN: 1617-4623
    Keywords: Key words Molybdenum cofactor biosynthesis ; Drosophila ; cinnamon ; cnx1 ; GEPHYRIN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molybdoenzymes are involved in a variety of essential pathways including nitrate assimilation, sulfur and/or purine metabolism and abscisic acid biosynthesis. Most organisms produce several such enzymes requiring a molybdopterin cofactor for catalytic function. Mutations that result in a lack of the molybdopterin cofactor display a pleiotropic loss of molybdoenzyme activities, and this phenotype has been used to identify genes involved in cofactor biosynthesis or utilization. Although several cofactor genes have been analyzed in prokaryotes, much less is known concerning eukaryotic molybdenum cofactor (MoCF) genes. This work is focused on the Drosophila MoCF gene cinnamon (cin) which encodes a multidomain protein, CIN, that shows significant similarity to three proteins encoded by separate prokaryotic MoCF genes. These domains are also present in the product of cnx1, an Arabidopsis MoCF gene, and in GEPHYRIN, a rat protein thought to organize the glycine receptor, GlyR, within the postsynaptic membrane. Since this apparent consolidation of separate prokaryotic genes into a single eukaryotic gene is a feature of other conserved metabolic pathways, we wished to determine whether the protein's function is also conserved. This report shows that the plant gene cnx1 can rescue both enzymatic and physiological defects of Drosophila carrying cin mutations, indicating that the two genes serve similar or identical functions. In addition, we have investigated the relationship between CINNAMON and GEPHYRIN, using immunohistochemical methods to localize the CIN protein in Drosophila embryos. Most of the CIN protein, like GEPHYRIN in the rat CNS, is localized to the cell borders and shows a tissue-specific pattern of expression. In a parallel study, antibody to GEPHYRIN revealed the same tissue-specific expression pattern in fly embryos. Both antibodies show altered staining patterns in cin mutants. Taken together, these results suggest that GEPHYRIN may also carry out a MoCF-related function.
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    HeT-A telomere-specific retrotransposons in the centric heterochromatin of Drosophila melanogaster chromosome 3 (1999)
    Springer
    Molecular genetics and genomics 262 (1999), S. 618-622 
    Details
    ISSN: 1617-4623
    Keywords: Key words Telomeric retrotransposons ; HeT-A elements ; Centric heterochromatin ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated two yeast artificial chromosome (YAC) clones from Drosophila melanogaster that contain a small amount of dodeca satellite (a satellite DNA located in the centromeric region of chromosome 3) and sequences homologous to the telomeric retrotransposon HeT-A. Using these YACs as probes for fluorescence in situ hybridization to mitotic chromosomes, we have localized these HeT-A elements to the centric heterochromatin of chromosome 3, at region h55. The possible origin of these telomeric elements in a centromeric position is discussed.
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    URL: http://dx.doi.org/10.1007/s004380051124
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    Epidermal growth factor receptor: its role in Drosophila eye differentiation and cell survival (1999)
    Springer
    Apoptosis 4 (1999), S. 239-243 
    Details
    ISSN: 1573-675X
    Keywords: Apoptosis ; cell survival ; differentiation ; Drosophila ; EGFR ; hid ; ras.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The Drosophila epidermal growth factor receptor (EGFR), functioning through the Ras/Raf/MAPK pathway, promotes cell proliferation and differentiation. Recent work has demonstrated that EGFR functions via the same Ras/Raf/MAPK pathway to promote cell survival. This review summarizes the role of EGFR in differentiation and survival during Drosophila eye development.
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    URL: http://dx.doi.org/10.1023/A:1009648724937
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    Genomic P elements and P-M characteristics of eastern Australian populations of Drosophila melanogaster (1999)
    Springer
    Genetica 106 (1999), S. 231-245 
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    ISSN: 1573-6857
    Keywords: P element ; repressor ; maternal effect ; Drosophila ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As part of our effort to monitor changes in the clinal pattern of P element-associated traits in eastern Australian Drosophila melanogaster, we investigated the genomic P elements of 293 isofemale lines collected in the period 1991–1994 from 45 localities. P elements were present in many copies in all genomes examined, with full-size P and KP element size classes accounting for the large majority. SR elements were not present in at least 92% of the lines tested. South of about 26° south Latitude (°SLat), the ratio of KP to full-size P elements (KP/P ratio) increased, correlating weakly with the P-M phenotypes of the populations, from moderately P populations (26–29°SLat) to M populations (37–38°SLat) North of 26°SLat, in weak P populations, the KP/P ratio was higher than between 26 and 29°Slat. The KP/P ratio appears to be higher in the northern populations than it was when previous studies were done. Overall, a high KP/P ratio among lines correlated roughly with a lack of P activity, but it also correlated with reduced repressor function. In a sample of 30 lines, a maternal effect of repressor function did not show a pattern with latitude, nor with KP/P ratio, nor with presence or absence of P activity.
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    URL: http://dx.doi.org/10.1023/A:1003918417012
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    Distribution of transposable elements in Drosophila species (1999)
    Springer
    Genetica 105 (1999), S. 43-62 
    Details
    ISSN: 1573-6857
    Keywords: distribution ; Drosophila ; retrotransposon ; transposable element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We present a global analysis of the distribution of 43 transposable elements (TEs) in 228 species of the Drosophila genus from our data and data from the literature. Data on chromosome localization come from in situ hybridization and presence/absence of the elements from southern analyses. This analysis shows great differences between TE distributions, even among closely related species. Some TEs are distributed according to the phylogeny of their host specie; others do not entirely follow the phylogeny, suggesting horizontal transfers. A higher number of insertion sites for most TEs in the genome of D. melanogaster is observed when compared with that in D. simulans. This suggests either intrinsic differences in genomic characteristics between the two species, or the influence of differing effective population sizes, although biases due to the use of TE probes coming mostly from D. melanogaster and to the way TEs are initially detected in species cannot be ruled out. Data on TEs more specific to the species under consideration are necessary for a better understanding of their distribution in organisms and populations.
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    URL: http://dx.doi.org/10.1023/A:1003718520490
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    Integration specificity of the hobo element of Drosophila melanogaster is dependent on sequences flanking the integration site (1999)
    Springer
    Genetica 105 (1999), S. 133-147 
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    ISSN: 1573-6857
    Keywords: Drosophila ; hobo ; hot spot ; integration specificity ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analyzed the integration specificity of the hobo transposable element of Drosophila melanogaster. Our results indicate that hobo is similar to other transposable elements in that it can integrate into a large number of sites, but that some sites are preferred over others, with a few sites acting as integration hot spots. A comparison of DNA sequences from 112 hobo integration sites identified a consensus sequence of NTNNNNAC, but this consensus was insufficient to account for the observed integration specificity. To begin to define the parameters affecting hobo integration preferences, we analyzed sequences flanking a donor hobo element, as well as sequences flanking a hobo integration hot spot for their relative influence on hobo integration specificity. We demonstrate experimentally that sequences flanking a hobo donor element do not influence subsequent integration site preference, whereas, sequences contained within 31 base pairs flanking an integration hot spot have a significant effect on the frequency of integration into that site. However, sequence analysis of the DNA flanking several hot spots failed to identify any common sequence motif shared by these sites. This lack of primary sequence information suggests that higher order DNA structural characteristics of the DNA and/or chromatin may influence integration site selection by the hobo element.
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    URL: http://dx.doi.org/10.1023/A:1003712619487
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    Structural instability of 297 element in Drosophila melanogaster (1999)
    Springer
    Genetica 105 (1999), S. 239-248 
    Details
    ISSN: 1573-6857
    Keywords: transposable elements ; LTR-retroelements ; rearrangements ; population genetics ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 297 element Southern pattern modifications previously detected in mutation accumulation lines of Drosophila melanogaster were further investigated by in situ hybridisation, Southern blotting with different combinations of genomic digest-probe, and PCR. Only one out of the nine pattern modifications studied could be interpreted as an excision and was detectable by in situ hybridisation to polytene chromosomes. Results were consistent with most pattern modifications being small rearrangements within the body of the element. In agreement with the existence of spontaneous rearrangements of this kind is the observation that many genomic copies of element 297 are defective and these are not limited to heterochromatin. These findings have important implications for the models of transposable element (TE) number regulation as well as for the study of genome evolution.
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    URL: http://dx.doi.org/10.1023/A:1003957606743
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    Transposable elements and genome evolution: the case of Drosophila simulans (1999)
    Springer
    Genetica 107 (1999), S. 113-120 
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    ISSN: 1573-6857
    Keywords: colonization ; Drosophila ; dynamic ; natural populations ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Drosophila simulans presents a large variation in copy number among various transposable elements (TEs) and among natural populations for a given element. Some elements such as HMS beagle, blood, flea, tirant, coral, prygun jockey, F, nomade and mariner are absent in most populations, except in one or two which have copies on their chromosome arms. This suggests that some TEs are being awakened in D. simulans and are in the process of invading the species while it is colonizing the world. The elements 412 and roo/B104 present a wide insertion polymorphism among D. simulans populations, but only the 412 copy number follows a temperature cline. One population (Canberra from Australia) has a very high copy number for the 412 element and for many other TEs as well, indicating that some populations may have lost control of some of their TEs. While the 412 transposition rate is similar in all populations, its transcription level throughout developmental stages varies with populations, depending on copy number. Populations with 412 copy number higher than 10–12 exhibit co-suppression, while the expression in populations with lower numbers depends on the insertion location. All these results suggest genomic invasions by 412 and other TEs during the worldwide spread of the D. simulans species.
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    URL: http://dx.doi.org/10.1023/A:1003937603230
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    Molecular domestication – more than a sporadic episode in evolution (1999)
    Springer
    Genetica 107 (1999), S. 197-207 
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    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; molecular domestication ; P element ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements are short but complex pieces of DNA or RNA containing a streamlined minimal-genome with the capacity for its selfish replication in a foreign genomic environment. Cis-regulatory sections within the elements orchestrate tempo and mode of TE expression. Proteins encoded by TEs mainly direct their own propagation within the genome by recruitment of host-encoded factors. On the other hand, TE-encoded proteins harbor a very attractive repertoire of functional abilities for a cell. These proteins mediate excision, replication and integration of defined DNA fragments. Furthermore, some of these proteins are able to manipulate important host factors by altering their original function. Thus, if the host genome succeeds in domesticating such TE-encoded proteins by taming their ‘anarchistic behavior,’ such an event can be considered as an important evolutionary innovation for its own benefit. In fact, the domestication of TE-derived cis-regulatory modules and protein coding sections took place repeatedly in the course of genome evolution. We will present prominent cases that impressively demonstrate the beneficial impact of TEs on host biology over evolutionary time. Furthermore, we will propose that molecular domestication might be considered as a resumption of the same evolutionary process that drove the transition from ‘primitive genomes’ to ‘modern’ ones at the early dawn of life, that is, the adaptive integration of a short piece of autonomous DNA into a complex regulatory network.
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    URL: http://dx.doi.org/10.1023/A:1004070603792
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    The bioavailability of magnesium from Wakame ( Undaria pinnatifida) and Hijiki (Hijikia fusiforme) and the effect of alginic acid on magnesium utilization of rats (1999)
    Springer
    Plant foods for human nutrition 53 (1999), S. 265-274 
    Details
    ISSN: 1573-9104
    Keywords: Bioavailability ; Magnesium ; Hijiki ; Sodium alginate ; Rat ; Wakame
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The bioavailability of magnesium from Wakame and Hijiki, and the effects of alginic acid on absorption of dietary magnesium were examined in five groups of rats fed either control, Wakame, Hijiki, AW (containing the same amount of alginate as in the Wakame) and AH (containing the same amount of alginate as in the Hijiki) diets, and animals fed a low magnesium diet (LMg) (twentieth amount of magnesium in the original mineral mixtures as the control). Food intake and body weight gain were decreased by adding sodium alginate to the diets. A large amount of calcium accumulated only in the kidneys of the rats fed the LMg diet. Serum magnesium concentration decreased only in the LMg group. The magnesium content in the defatted left femurs did not differ between the control and Wakame fed animals and also among the animals eating Wakame, Hijiki and AW diets. The breaking force of the right femurs did not differ among all the groups except the LMg group. The ratio of apparent magnesium absorption (%) of the control, LMg, Wakame, Hijiki, AW and AH groups was 82.2, 72.7, 66.9, 50.8, 69.3 and 54.2 in the first experimental period, and was 75.3, 52.1, 57.7, 46.9, 62.6 and 60.5 in the second experimental period, respectively. It was clear that the bioavailability of magnesium in the Wakame fed rats was higher than in those eating the Hijiki. Large amounts of sodium alginate lowered magnesium absorption from the diet.
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    URL: http://dx.doi.org/10.1023/A:1008082112178
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    Identification of nuclear genes encoding mitochondrial proteins: isolation of a collection of D. melanogaster cDNAs homologous to sequences in the Human Gene Index database (1999)
    Springer
    Molecular genetics and genomics 261 (1999), S. 64-70 
    Details
    ISSN: 1617-4623
    Keywords: Key words Mitochondrial proteins ; Nuclear genes ; Drosophila ; Evolutionary conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As a first step towards using cross-species comparison to complete the inventory of the nuclear genes that encode mitochondrial polypeptides, and ultimately to understand their function through systematic molecular and genetic analysis in a model organism of choice, we report here the characterization of 41 Drosophila melanogaster cDNAs. These cDNAs were isolated by screening an ovarian expression library with antibodies against mitochondrial proteins and identify 17 novel Drosophila genes. The deduced amino acid sequences encoded by the majority of these cDNAs turned out to show significant homology to mitochondrial proteins previously identified in other species. Among others, ORFs putatively encoding six different subunits of ATP synthase and three NADH:ubiquinone reductase subunits were detected. By in situ hybridization, all cDNAs were mapped to single bands on polytene chromosomes, thus identifying candidate Drosophila genes required for mitochondrial biogenesis and maintenance. A search of the Human Gene Index database made it possible in most cases to align the entire Drosophila coding sequence with a human consensus sequence, suggesting that the cDNAs originate from insect counterparts of expressed mammalian genes. Our experimental strategy represents an efficient approach to the identification and interspecies comparison of genes encoding products targeted to the mitochondrion.
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    URL: http://dx.doi.org/10.1007/s004380050942
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    Microspatial genetic differentiation for tolerance and utilization of various alcohols and acetic acid in Drosophila species from India (1999)
    Springer
    Genetica 105 (1999), S. 249-258 
    Details
    ISSN: 1573-6857
    Keywords: alcoholic resources ; Drosophila ; habitat selection ; Indian subcontinent ; short range variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In five Indian localities, it was possible to collect D. melanogaster in two different types of habitats, namely ordinary domestic and alcohol rich ones. Tolerance and utilization capacity of several alcohols and of acetic acid were analyzed in a total of 10 local populations. Results on two other species (D. repleta and D. immigrans) were also available from one place. In each locality, the population from alcohol rich habitat proved to be more tolerant to all the investigated products and also to be more capable of using them as a resource. Alcohols toxicity increased with increasing carbon chain length and secondary alcohols were more toxic than primary ones. Utilization capacity of all products was relatively independent of their toxicity. Especially acetic acid, the toxicity of which was low and similar to that of ethanol, was always a fairly poor resource. From a genetic point of view, tolerance and utilization capacity appeared as two relatively independent traits. Natural selection, which is responsible for the genetic differentiation of local populations, is likely to act simultaneously on both traits.
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    URL: http://dx.doi.org/10.1023/A:1003815626258
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    How valuable are model organisms for transposable element studies? (1999)
    Springer
    Genetica 107 (1999), S. 103-111 
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    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; model organisms ; transposons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Model organisms have proved to be highly informative for many types of genetic studies involving ‘conventional’ genes. The results have often been successfully generalized to other closely related organisms and also, perhaps surprisingly frequently, to more distantly related organisms. Because of the wealth of previous knowledge and their availability and convenience, model organisms were often the species of choice for many of the earlier studies of transposable elements. The question arises whether the results of genetic studies of transposable elements in model organisms can be extrapolated in the same ways as those of conventional genes? A number of observations suggest that special care needs to be taken in generalizing the results from model organisms to other species. A hallmark of many transposable elements is their ability to amplify rapidly in species genomes. Rapid spread of a newly invaded element throughout a species range has also been demonstrated. The types and genomic copy numbers of transposable elements have been shown to differ greatly between some closely related species. Horizontal transfer of transposable elements appears to be more frequent than for nonmobile genes. Furthermore, the population structure of some model organisms has been subject to drastic recent changes that may have some bearing on their transposable element genomic complements. In order to initiate discussion of this question, several case studies of transposable elements in well-studied Drosophila species are presented.
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    Evidence for genomic regulation of the telomeric activity in Drosophila melanogaster (1999)
    Springer
    Genetica 107 (1999), S. 95-102 
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    ISSN: 1573-6857
    Keywords: Drosophila ; genomic regulation ; telomeric activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structural integrity of TART elements has been used as reporter of instability at chromosomal ends in numerous Drosophila stocks and over time in an unstable stock. The results show that telomeric activity is a regulated process that may differ between the stocks as well as over time within a stock.
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    URL: http://dx.doi.org/10.1023/A:1003911925791
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    TTAGG Telomeric Repeats in Chromosomes of Some Insects and Other Arthropods (1999)
    Springer
    Chromosome research 7 (1999), S. 449-460 
    Details
    ISSN: 1573-6849
    Keywords: Apis ; Bombyx ; Drosophila ; Ephestia ; fluorescence in-situ hybridization (FISH) ; Galleria ; Gammarus ; insect phylogeny ; Ips ; Locusta ; Megaselia ; Pyrrhocoris ; Southern hybridization ; Tegenaria ; telomere ; Tenebrio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the occurrence of the TTAGG telomere repeats by fluorescence in-situ hybridization (FISH) and Southern hybridization in ten insect species and two other arthropods. (TTAGG)n-containing telomeres were found in three Lepidoptera species, the silkworm Bombyx mori (in which the telomeric sequence was recently discovered), the flour moth Ephestia kuehniella, and the wax moth Galleria mellonella, in one species of Hymenoptera, the honey bee Apis mellifera, in one species of Coleoptera, the bark beetle Ips typographus, in one species of Orthoptera, the locust Locusta migratoria, and in a crustacean, the amphipod Gammarus pulex. They were absent in another species of Coleoptera, the mealworm Tenebrio molitor, two representatives of Diptera, Drosophila melanogaster and Megaselia scalaris, a species of Heteroptera, the bug Pyrrhocoris apterus and a spider, Tegenaria ferruginea. Our results, which confirm and extend earlier observations, suggest that (TTAGG)n was a phylogenetically ancestral telomere motif in the insect lineage but was lost independently in different groups, being replaced probably by other telomere motifs. In the Coleoptera this must have happened rather recently as even members of the same family, Curculionidae, differ with respect to the telomeric DNA.
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    Does evolution reduce the body size? A study of the four members of newly evolved nasuta‐albomicans complex of Drosophila (1999)
    Springer
    Genetica 105 (1999), S. 1-6 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; nasuta-albomicans ; complex ; cytoraces ; body size ; fertility ; ovariole number ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our long range interracial hybridization experiments between a pair of cross fertile races, Drosophila nasuta (2n = 8) and D.albomicans (2n = 6) have resulted in the evolution of two new karyotypic strains under laboratory conditions, which are named as Cytorace 1 and Cytorace 2. These Cytoraces harbor chromosomes from both parents. Here, we compare the body size of the parental races and newly evolved Cytoraces and the relationship between the body size and fitness. Analysis reveals that the parental races have reduced fertility and are larger in body size than newly evolved Cytoraces. Thus, the newly evolved Cytoraces show reduced body size and better fitness in the course of their evolution.
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    An improved method for the purification of stellate cells from rat liver with Dichloromethylene Diphosphate (CL2MDP) (1999)
    Springer
    Methods in cell science 21 (1999), S. 19-24 
    Details
    ISSN: 1573-0603
    Keywords: Dichloromethylene diphosphate ; Hepatic stellate cell isolation ; Liposome ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hepatic perisinusoidal cell population consists of hepatic stellate cells, Kupffer cells, endothelial cells, and Pit cells. These cells are isolated by enzymic digestion and purified by density gradient centrifugation. With isolation of stellate cells, conventional method is unable to eliminate the contamination of Kupffer cells because the densities of these two cells are similar. We report here an improved method for isolation of highly purified hepatic stellate cells, using dichloromethylene diphosphate (CL2MDP), which has selective cytotoxicity of Kupffer cells. Three days after the single intravenous administration of liposome-encapsulated CL2MDP, the Kupffer cells disappeared almost completely from the liver. Following Percoll density gradient centrifugation, the purity of the hepatic stellate cells exceeded 98% without any contamination of the Kupffer cells. Kupffer cells are reported to affect the physiological functions of stellate cells. The availability of highly purified stellate cells will facilitate the investigation of their functions in primary culture.
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    A Simple Cytological Technique to Analyze Nuclear Divisions During Preblastodermic Development in Drosophila (1999)
    Springer
    Chromosome research 7 (1999), S. 445-448 
    Details
    ISSN: 1573-6849
    Keywords: chromosomes ; cytological technique ; Drosophila ; embryos ; mitosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1023/A:1009245712709
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    Size and shape heritability in natural populations of Drosophila mediopunctata: temporal and microgeographical variation (1999)
    Springer
    Genetica 105 (1999), S. 35-42 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; heritability ; principal component analysis ; shape ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ‘Traditional morphometrics’ allows us to decompose morphological variation into its major independent sources, identifying them usually as size and shape. To compare and investigate the properties of size and shape in natural populations of Drosophila mediopunctata, estimating their heritabilities and analysing their temporal and microgeographic changes, we carried out collections on seven occasions in Parque Nacional do Itatiaia, Brazil. In one of these collections, we took samples from five different altitudes. Measurements were taken from wild caught inseminated females and up to three of their laboratory‐reared daughters. Through a principal component analysis, three major sources of variation were identified as due to size (the first one) and shape (the remaining two). The overall amount of variation among laboratory flies was about half of that observed among wild flies and this reduction was primarily due to size. Shape variation was about the same under natural and artificial conditions. A genetic altitudinal cline was detected for size and shape, although altitude explained only a small part of their variation. Differences among collections were detected both for size and shape in wild and laboratory flies, but no simple pattern emerged. Shape variation had high heritability in nature, close to or above 40% and did not vary significantly temporally. Although on the overall size heritability (18 ± 6%)was significant its estimates were not consistent along months – they were non‐significant in all but one month, when it reached a value of 51 ± 11%. Overall, this suggests that size and shape have different genetic properties.
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    Developmental Isolation and Subsequent Adult Behavior of Drosophila paulistorum. V. Survey of Six Sibling Species (1999)
    Springer
    Behavior genetics 29 (1999), S. 65-73 
    Details
    ISSN: 1573-3297
    Keywords: Mating behavior ; reproductive isolation ; sexual isolation ; sibling species ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract In an investigation into the effects of developmental isolation from all conspecifics, the Drosophila willistoni group of six sibling species responded to differing degrees: all six are reproductively isolated from D. paulistorum, the tester species. Drosophila pavlovskiana, a narrow endemic, proved the most vulnerable, responding by reducing its adult sexual isolation, if eggs, any instar, and sometimes even pupae were socially isolated. To lesser degrees, D. tropicalis and D. willistoni both produced similar results only when their eggs were isolated, i.e., when from the moment of egg deposition on, there was absolutely no contact with other flies until testing for mating behavior. The remaining siblings, D. equinoxialis and D. insularis, were immovable.
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    Oviposition-Site Preference in Drosophila Following Interspecific Gene Transfer of the Alcohol dehydrogenase Locus (1999)
    Springer
    Behavior genetics 29 (1999), S. 199-204 
    Details
    ISSN: 1573-3297
    Keywords: Drosophila ; oviposition-site preference ; alcohol dehydrogenase ; transgene coplacement ; ethanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The preference of Drosophila females to lay eggs on substrates that do or do not contain alcohol is an excellent system to study the evolutionary genetics of behavior, because (1) there is variation in this behavior within and among species, (2) the behavior is amenable to laboratory investigation, and (3) the behavior presumably has a direct relationship to reproductive fitness. Moreover, a key genetic component of the system, the Alcohol dehydrogenase (Adh) locus, is arguably the most well characterized gene known. However, because the Adh gene and its genetic background are inseparable in reproductively isolated species, it is difficult to establish its role in behavioral divergence. By transgene coplacement, we created pairs of strains of D. melanogaster expressing an Adh allele from either D. melanogaster or D. affinidisjuncta, a Hawaiian species with very low levels of ADH in adults. When raised on ethanol-containing medium, the affinidisjuncta–Adh strains experience high mortality relative to the melanogaster–Adh strains. However, affinidisjuncta–Adh females show the same preference for oviposition on ethanol-containing medium as melanogaster–Adh females. Thus, preference for ethanol in these strains is not determined primarily by Adh genotype.
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    Two non-linked genes for specific virulence of Leptopilina boulardi against Drosophila melanogaster and D. yakuba (1999)
    Springer
    Evolutionary ecology 13 (1999), S. 211-220 
    Details
    ISSN: 1573-8477
    Keywords: Drosophila ; evolutionary genetics ; host specificity ; parasitoid ; virulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The developmental success of Leptopilina boulardi parasitoids within host species of the melanogaster subgroup is determined mainly by their ability to suppress the host immune reaction (virulence). Host resistance and parasitoid virulence are genetically variable in both partners. A gene for specific resistance against L. boulardi (Rlb) has been identified in Drosophila melanogaster, and a gene for the immune suppression (IS) of D. melanogaster has been identified in L. boulardi. To understand the evolution of the IS gene, we determined its specificity regarding potential hosts of the melanogaster subgroup. It did not affect the virulence against any other species of the melanogaster subgroup and was called ISm for immune suppression of D. melanogaster. Another gene (ISy), non-linked to the gene ISm, was characterized for the specific immune suppression of D. yakuba. These results suggesting that natural selection for virulence against one host species does not influence the evolution of virulence against another will allow us to develop pertinent hypotheses concerning the evolution of this character which is expected to drive the evolution of the parasitoid toward narrow host specialization.
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    URL: http://dx.doi.org/10.1023/A:1006691431658
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    Environmental effects on cytoplasmic incompatibility and bacterial load in Wolbachia-infected Drosophila simulans (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    Details
    ISSN: 1570-7458
    Keywords: Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
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    Host Preference Among Populations of Drosophila mojavensis (Diptera: Drosophilidae) that Use Different Host Cacti (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 691-712 
    Details
    ISSN: 1572-8889
    Keywords: cactus ; Drosophila ; geographic variation ; host preference behavior ; Sonoran Desert ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory “olfactometer” by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.
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    Interactions of the Males and Females of Three Sympatric Drosophila virilis-Group Species, D. montana, D. littoralis, and D. lummei, (Diptera: Drosophilidae) in Intra- and Interspecific Courtships in the Wild and in the Laboratory (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 399-417 
    Details
    ISSN: 1572-8889
    Keywords: courtship behavior ; songs ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.
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    Calcium-binding proteins and development (1998)
    Springer
    BioMetals 11 (1998), S. 359-372 
    Details
    ISSN: 1572-8773
    Keywords: calcium ; EGF-domains ; cadherins ; integrins ; calmodulin ; cytoskeleton ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The known roles for calcium-binding proteins in developmental signaling pathways are reviewed. Current information on the calcium-binding characteristics of three classes of cell-surface developmental signaling proteins (EGF-domain proteins, cadherins and integrins) is presented together with an overview of the intra-cellular pathways downstream of these surface receptors. The developmental roles delineated to date for the universal intracellular calcium sensor, calmodulin, and its targets, and for calcium-binding regulators of the cytoskeleton are also reviewed.© Kluwer Academic Publishers
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    URL: http://dx.doi.org/10.1023/A:1009201824806
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    Effects of Courtship Song in Interspecific Crosses Among the Species of the Drosophila auraria Complex (Diptera: Drosophilidae) (1998)
    Springer
    Journal of insect behavior 11 (1998), S. 383-398 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; courtship song ; behavior ; female choice ; sexual isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The courtship behavior and the effects of courtship song in inter- and intraspecific crosses were studied in the four sympatric species of the Drosophila auraria complex: D. auraria, D. biauraria, D. subauraria, and D. triauraria. Orientation, tapping, and vibration (the repertoires of male courtship) were observed in both inter- and intraspecific crosses, suggesting that signals from heterospecific females were enough to elicit such male behaviors. The crossability tests with wingless or winged heterospecific males (tests for wing effects) revealed that winged heterospecific males copulated less than wingless ones in all four species but not all the pairwise cases. Since the crossability tests with aristaless females (deaf) or normal females showed essentially the same results as the tests for wing effects, we concluded that the sound produced by wing vibration plays an important role and that the wing movement itself is less important. These findings suggest that courtship songs are of great importance in mate discrimination and the sexual isolation between the species of this complex.
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    The wingless gene is required for embryonic brain development in Drosophila (1998)
    Springer
    Development genes and evolution 208 (1998), S. 37-45 
    Details
    ISSN: 1432-041X
    Keywords: Key words wingless ; Wnt ; Drosophila ; Brain development ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have studied the role of the wingless gene in embryonic brain development of Drosophila. wingless is expressed in a large domain in the anlage of the protocerebrum and also transiently in smaller domains in the anlagen of the deutocerebrum and tritocerebrum. Elimination of the wingless gene in null mutants has dramatic effects on the developing protocerebrum; although initially generated, approximately one half of the protocerebrum is deleted in wingless null mutants by apoptotic cell death at late embryonic stages. Using temperature sensitive mutants, a rescue of the mutant phenotype can be achieved by stage-specific expression of functional wingless protein during embryonic stages 9–10. This time period correlates with that of neuroblast specification but preceeds the generation and subsequent loss of protocerebral neurons. Ectopic wingless over-expression in gain-of-function mutants results in dramatically oversized CNS. We conclude that wingless is required for the development of the anterior protocerebral brain region in Drosophila. We propose that an important role of wingless in this part of the developing brain is the determination of neural cell fate.
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    The expression of histone genes during Drosophila melanogaster oogenesis (1998)
    Springer
    Development genes and evolution 207 (1998), S. 535-541 
    Details
    ISSN: 1432-041X
    Keywords: Key words Histones ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A genomic fragment was cloned from a DNA library constructed from a Drosophila enhancer trap line in which reporter gene expression was observed at the anterior-most tip of the ovaries and testes. This genomic clone was identified as the L-repeat of the Drosophila melanogaster histone gene cluster. Northern blotting and in situ hybridisation to RNA in tissues with individual cDNAs and PCR-generated probes for each histone confirmed that gene expression was greatest at the anterior portion of each ovariole, in the germarium, and was also elevated in a few individual nurse cells and somatic follicle cells within the egg chamber during early developmental stages. Histone H1 and each of the core histones had a similar expression pattern which was correlated to cell division. Maternal stores of histone transcripts were also transported to the mature oocyte from the nurse cells at a later stage of oogenesis (stage 10), when virtually all the nurse cells contained high levels of histone transcripts. The results are consistent with expression of the somatic histone gene cluster during oogenesis as a co-ordinate unit. There does not seem to be a reduced level of somatic type H1 in the germ-line, as is observed in some other species. The relationship between the P[lacZ] expression pattern in the germarium and the overall expression of the histone cluster suggests there are specific regulatory elements for germ-line expression.
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    Naturally occurring genetic variation affects Drosophila photoreceptor determination (1998)
    Springer
    Development genes and evolution 207 (1998), S. 462-470 
    Details
    ISSN: 1432-041X
    Keywords: Key words Genetic variation ; Sevenless ; EGF receptor ; Drosophila ; Photoreceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The signal transduction pathway controlling determination of the identity of the R7 photoreceptor in the Drosophila eye is shown to harbor high levels of naturally occurring genetic variation. The number of ectopic R7 cells induced by the dosage-sensitive Sev S11.1 transgene that encodes a mildly activated form of the Sevenless tyrosine kinase receptor is highly sensitive to the wild-type genetic background. Phenotypes range from complete suppression to massive overproduction of photoreceptors that exceeds reported effects of known single gene modifiers, and are to some extent sex-dependent. Signaling from the dominant gain-of-function Drosophila Epidermal Growth Factor Receptor (DER-Ellipse) mutations is also sensitive to the genetic backgrounds, but there is no correlation with the effects on Sev S11.1 . This implies that different genes and/or alleles modify the two activated receptor genotypes. The evolutionary significance of the existence of high levels of genetic variation in the absence of normal phenotypic variation is discussed.
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    Structural organization of rat CD1 typifies evolutionarily conserved CD1D class genes (1998)
    Springer
    Immunogenetics 48 (1998), S. 22-31 
    Details
    ISSN: 1432-1211
    Keywords: Key words CD1 ; Rat ; Gene ; Organization ; Polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The non-major histocompatibility complex (MHC)-encoded CD1 family has recently emerged as a new antigen-presenting system that is distinct from either MHC class I or class II molecules. In the present study, we determined the genomic structure of the rat CD1 locus. It was extremely similar to mouse CD1 genes, especially to CD1D1. The 5′ flanking region of the CD1 gene contained the binding motifs for two cytokine-inducible transcription factors, NF-IL2-A and NF-IL6. Some regulatory elements found in MHC class I genes (enhancer A, enhancer B, and the IFN response element) were absent. It is of interest that a tyrosine-based motif for endosomal localization found in the human CD1b cytoplasmic tail was encoded by a single short exon which was conserved in all CD1 molecules except for CD1a. Southern blot and direct sequencing analyses of inbred rat strains suggested very limited polymorphism in the 5′ region where a hydrophobic ligand-binding groove is encoded; a single base substitution resulted in amino acid alteration of alanine (GCT) to valine (GTT) at codon 119. Comparison of the overall exon-intron organization of CD1 genes revealed that the length of the intron was also characteristic to each of the two classes of CD1 genes, classic CD1 and CD1D; such categorization has hitherto been made according to the sequence similarity of the coding region. This finding provides further support for the hypothesis that the two classes have different evolutionary histories. In contrast to the complete absence of the classic CD1 in rats and mice, the entire region of nonpolymorphic CD1D has been conserved through mammalian evolution. Similar functional properties of rodent CD1 and human CD1d are implied.
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    Structural organization, sequence analysis, and physical mapping of the Grc-linked class Ib gene RT1.S3 in the rat (1998)
    Springer
    Immunogenetics 48 (1998), S. 76-81 
    Details
    ISSN: 1432-1211
    Keywords: Key words RT1.S3 ; Grc ; MHC ; Class I ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Effects of space flight on GLUT-4 content in rat plantaris muscle (1998)
    Springer
    International journal of biometeorology 41 (1998), S. 101-104 
    Details
    ISSN: 1432-1254
    Keywords: Key words Space flight ; Rat ; Plantaris muscle ; GLUT-4 ; Citrate synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  The effects of 14 days of space flight on the glucose transporter protein (GLUT-4) were studied in the plantaris muscle of growing 9-week-old, male Sprague Dawley rats. The rats were randomly separated into five groups: pre-flight vivarium ground controls (PF-VC) sacrificed approximately 2 h after launch; flight groups sacrificed either approximately 5 h (F-R0) or 9 days (F-R9) after the return from space; and synchronous ground controls (SC-R0 and SC-R9) sacrificed at the same time as the respective flight groups. The flight groups F-R0 and F-R9 were exposed to micro-gravity for 14 days in the Spacelab module located in the cargo bay of the shuttle transport system – 58 of the manned Space Shuttle for the NASA mission named ”Spacelab Life Sciences 2”. Body weight and plantaris weight of SC-R0 and F-R0 were significantly higher than those of PF-VC. Neither body weight nor plantaris muscle weight in either group had changed 9 days after the return from space. As a result, body weight and plantaris muscle weight did not differ between the flight and synchronous control groups at any of the time points investigated. The GLUT-4 content (cpm/µg membrane protein) in the plantaris muscle did not show any significant change in response to 14 days of space flight or 9 days after return. Similarly, citrate synthase activity did not change during the course of the space flight or the recovery period. These results suggest that 14 days of space flight does not affect muscle mass or GLUT-4 content of the fast-twitch plantaris muscle in the rat.
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    Expression of the nuclear gene encoding mitochondrial ATP synthase subunit α in early development of Drosophila and sea urchin (1998)
    Springer
    Molecular biology reports 25 (1998), S. 87-94 
    Details
    ISSN: 1573-4978
    Keywords: mitochondria ; Drosophila ; sea urchin ; ATP synthase ; embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Complementary DNAs encoding nuclear-coded mitochondrial ATP synthase subunit α of Drosophila melanogaster and Strongylocentrotus purpuratus were obtained by a combination of library screening and redundant PCR. The entire coding sequence of the precursor polypeptide was inferred for both species. Southern blots to genomic DNA indicated that the gene is almost certainly single-copy in both organisms. Northern blots to RNA from staged developmental series showed that ATP synthase subunit α mRNA is represented in the egg, declines in abundance during cleavage, and is replenished by zygotic transcription in both species. However, the extent and timing of these changes differ significantly in the two species studied. Nuclear-coded and mitochondrially encoded ATP synthase genes appear to be temporally co-regulated in Drosophila, but not sea urchin development.
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    Female encounter rates and fighting costs of males are associated with lek size in Drosophila mycetophaga (1998)
    Springer
    Behavioral ecology and sociobiology 42 (1998), S. 163-169 
    Details
    ISSN: 1432-0762
    Keywords: Key words Lek behavior ; Mating ecology ; Ideal free distribution ; Body size ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Male costs and benefits associated with male display size in field populations of an Australian lekking Drosophila species were examined. Results suggested that male mating success increased with display size, since matings appeared to be more common in large displays, and since the probability of males encountering a female increased as displays contained more males. Female encounter probabilities did not increase once about 20 males or more were present on a display. Male size and fighting costs tended to increase with display size. The distribution of males among displays did not follow the ideal free distribution in the sense that each male did not have equal mating opportunity per unit time. Deviation from an ideal free distribution may have been due to female preference for mating in aggregations rather than with solitary males, since in a field experiment females were more willing for mating in an aggregation of five males than with solitary males.
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    N18-RE-105 cells: differentiation and activation of p53 in response to glutamate and adriamycin is blocked by SV40 large T antigen tsA58 (1998)
    Springer
    Cell & tissue research 291 (1998), S. 191-205 
    Details
    ISSN: 1432-0878
    Keywords: Key words N18-RE-105 cells ; Glutamate ; p53 ; Adriamycin ; Etoposide ; Differentiation ; SV40 large T antigen ; Mouse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Process extension was induced in cells of the N18-RE-105 neuroblastoma-retinal hybrid line by toxic agents, including glutamate and the p53-inducing anticancer agents adriamycin and etoposide. Both adriamycin and glutamate activated p53 as measured by a plasmid transfection assay. It was therefore hypothesized that SV40 large T antigen, which binds p53, would interfere with cellular differentiation. To test this hypothesis, the temperature-sensitive form of SV40 large T was transduced into N18-RE-105 cells by retroviral infection. SV40 large T-infected cells became de-differentiated, grew in tightly-packed colonies, lost expression of neurofilament, and lost the ability to differentiate in response to glutamate and adriamycin. The de-differentiating effect of SV40 large T antigen may be due to binding and inactivation of cellular proteins, such as p53, p107, p130, p300, and retinoblastoma protein, which are important in cellular growth and differentiation. It is suggested that p53 may play a role in cellular differentiation, perhaps under unusual circumstances involving stress or cytotoxicity.
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    Localization of elastin mRNA and TGF-β1 in rat aorta and caudal artery as a function of age (1998)
    Springer
    Cell & tissue research 291 (1998), S. 305-314 
    Details
    ISSN: 1432-0878
    Keywords: Key words Elastin ; TGF-β1 ; Arteries ; In situ hybridization ; Immunohistochemistry ; Northern blot ; Ageing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Several in vitro studies have previously demonstrated that the addition of TGF-β to aortic smooth muscle cells or skin fibroblasts stimulates elastin synthesis. It is not clear however whether, in vivo, TGF-β participates in the regulation of elastin synthesis, especially in physiological conditions. The aim of our study was to explore the localization of elastin mRNA and TGF-β1 in the rat thoracic aorta (an elastic artery) and caudal artery (a muscular artery). Elastin mRNA was localized by in situ hybridization and quantified using Northern blot analysis. TGF-β1 was detected using immunohistochemistry. The study was carried out as a function of age (rats of 3, 10, 20, and 30 months). We observed that TGF-β1 immunoreactivity is present predominantly, but not exclusively, at the sites of elastin synthesis as determined by elastin mRNA detection: in smooth muscle cells in the aorta and in endothelial cells in the caudal artery. The ability of exogenously added TGF-β1 (0.001–10 ng/ml) to modulate the steady-state levels of elastin mRNA in primary cultures of endothelial cells, smooth muscle cells, and fibroblasts isolated from the thoracic aorta was also studied. At the highest concentration used, elastin mRNA levels increased 5-fold in endothelial cells and 11-fold in smooth muscle cells. The demonstration that TGF-β1 immunoreactivity is present at the sites of elastin synthesis in the thoracic aorta and in the caudal artery and the observation that TGF-β1 induces an increase in elastin mRNA levels in cultured endothelial cells and smooth muscle cells suggest that TGF-β1 may be implicated, at least in part, in the physiological regulation of elastin gene expression.
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    A culture substratum appropriate for brain cells is a chondroitin sulfate glycosaminoglycan in serum (1998)
    Springer
    Cell & tissue research 291 (1998), S. 445-454 
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    ISSN: 1432-0878
    Keywords: Key words Serum-free medium ; Survival ; Chondroitin sulfate ; Culture substratum ; Brain neuron ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  When cells dissociated from the neonatal rat brains are plated on a poly-lysine-coated surface in a serum-free medium, they display a strange morphology: a dark and extended cell body. Preincubation of the surface with fetal bovine serum was found to inhibit the appearance of this strange contraction of the basal cell sheets in a dose-dependent manner. This finding indicated the presence of a factor(s) in the serum, which might be an appropriate substratum for prolonged survival of brain neurons. In the current study, this factor was highly purified through DEAE ion-exchange chromatography followed by gel filtration. The factor was eluted from a Superose column at fractions corresponding to a molecular weight greater than 1000 kDa. By SDS-PAGE analysis, these fractions were found to contain a major band (≥1000 kDa) positive for alcian blue and few minor bands faintly stainable with Coomassie blue. The activity of the purified sample, inducing the morphological change in cells, was diminished by incubation with chondroitinase ABC. Neither heparitinase II, hyaluronidase, nor trypsin modified the activity. An authentic chondroitin sulfate (type B) mimicked the serum action on the morphology of brain cells in early stages of culture. Taking these findings together, it is suggested that the factor in serum beneficial for the attachment of brain cells is composed of a chondroitin sulfate with a Mr greater than 1000 kDa. Cortical cells dissociated from the neonatal rat brain attached well to the purified factor-coated surface and displayed a healthy morphology: an optically-reflective cell body with thick neurites for at least 3 days in the absence of serum.
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    Double-labeling techniques demonstrate that rod bipolar cells are under GABAergic control in the inner plexiform layer of the rat retina (1998)
    Springer
    Cell & tissue research 292 (1998), S. 17-25 
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    ISSN: 1432-0878
    Keywords: Key words Retina ; Rod bipolar cells ; Amacrine cells ; Protein kinase C ; Glutamic acid decarboxylase ; GABA ; Synaptic circuitry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The synaptic connectivity between rod bipolar cells and GABAergic neurons in the inner plexiform layer (IPL) of the rat retina was studied using two immunocytochemical markers. Rod bipolar cells were stained with an antibody specific for protein kinase C (PKC, α isoenzyme), and GABAergic neurons were stained with an antiserum specific for glutamic-acid decarboxylase (GAD). Some amacrine cells were also labeled with the anti-PKC antiserum. All PKC-labeled amacrine cells examined showed GABA immunoreactivity, indicating that PKC-labeled amacrine cells constitute a subpopulation of GABAergic amacrine cells in the rat retina. A total of 150 ribbon synapses established by rod bipolar cells were observed in the IPL. One member of the postsynaptic dyads was always an unlabeled AII amacrine cell process, and the other belonged to an amacrine-cell process showing GAD immunoreactivity. The majority (n=92) (61.3%) of these processes made reciprocal synapses back to the axon terminals of rod bipolar cells. In addition, 78 conventional synapses onto rod bipolar axons were observed, and among them 52 (66.7%) were GAD-immunoreactive. Thus GABA provides the major inhibitory input to rod bipolar cells.
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    Neuronal differentiation is accompanied by NSP-C expression (1998)
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    Cell & tissue research 292 (1998), S. 229-237 
    Details
    ISSN: 1432-0878
    Keywords: Key words PC12 ; hNT2 ; Neuroblastoma cell lines ; NGF ; Retinoic acid ; Rat ; Human cell lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Neuroendocrine-specific protein (NSP) reticulons are expressed in neural and neuroendocrine tissues and cell cultures derived therefrom, while most other cell types lack NSP-reticulons. Three major subtypes have been identified so far, designated NSP-A, NSP-B, and NSP-C. We have investigated the correlation between the degree of neuronal differentiation, determined by morphological and biochemical criteria, and NSP-reticulon subtype expression. For this purpose, several human neuroblastoma cell lines, exhibiting different degrees of neuronal differentiation, were examined immuno(cyto) chemically. It became obvious that the expression of NSP-C, as detected by immunofluorescence microscopy and Western blotting, is most prominent in cell lines with a high degree of neuronal differentiation, such as LA-N-5. Such highly differentiated cells also express other neural and neuroendocrine markers, such as neural cell adhesion molecule (NCAM), neurofilament proteins, synaptophysin, and chromogranin. NSP-A was observed in all cell lines to a different extent. However, no clear correlation was observed with the degree of neuronal differentiation as defined by other neuronal and neuroendocrine markers or morphology. NSP-B could not be detected. The induction of neuronal differentiation with nerve growth factor, dbcAMP, and retinoic acid in the rat pheochromocytoma cell line PC12 and the human teratocarcinoma cell line hNT2, respectively, induced the expression of NSP-A and NSP-C in these cell lines parallel to the induction of neurofilament protein expression. It is concluded that NSP-C expression, in particular, is strongly correlated with neuronal differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051054
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  • 94
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    Light- and electron-microscopic study of the distribution of axons containing substance P and the localization of neurokinin-1 receptor in bone (1998)
    Springer
    Cell & tissue research 293 (1998), S. 87-93 
    Details
    ISSN: 1432-0878
    Keywords: Key words Osteoclasts ; Osteoblasts ; Osteocytes ; Bone ; Substance P (SP) ; Neurokinin-1 receptor (NK1-R) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Substance P (SP) is a neuropeptide that is released from axons of sensory neurons and causes signal transduction through the activation of the neurokinin-1 receptor (NK1-R). The present study demonstrates the distribution of SP-like-immunoreactive (SP-LI) axons and the localization of NK1-Rs in rat bone tissue using the avidin-biotin-peroxidase complex method. Axons with SP-LI were commonly found near the trabecular bone in the temporal bone marrow, but they were only sparsely distributed in the mandible, femur, and tibia. Immunoreactivity for NK1-Rs was found on the plasma membrane and in the cytoplasm of the osteoclasts. In the osteoblasts and osteocytes, a small number of weak, punctate immunoreactive products of NK1-Rs were distributed close to the plasma membrane. At the electron-microscopic level, immunoreactivity for NK1-R was distributed mainly in the whole cytoplasm, except for the clear zone of the osteoclasts, and in pit-like structures along the plasma membrane. The NK1-R-immunoreactive structures in the cytoplasm were divided into two types of organelles, consisting of vesicular and vacuolar structures (probably transport vesicles and early endosomes). In the osteoblasts and osteocytes, the number of NK1-R-positive vesicular structures was fewer than in the osteoclasts. These results thus suggest that SP secreted by the sensory axons could directly modulate bone metabolism via NK1-Rs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051100
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  • 95
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    The internal and external protein scaffold of the T-tubular system in cardiomyocytes (1998)
    Springer
    Cell & tissue research 294 (1998), S. 449-460 
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    ISSN: 1432-0878
    Keywords: Key words Vinculin ; Talin ; Integrin ; Dystrophin ; Spectrin ; T-tubule ; Costamere ; Basal membrane ; Cardiac muscle cell ; Dilated cardiomyopathy ; Human ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The transverse tubule system of the cardiomyocyte remains undeformed despite the extreme forces it undergoes during the contraction-relaxation cycle, but the morphological basis for its stability remains unclear. Therefore, we have investigated the architecture and subcellular protein scaffold of the cardiac T-tubules and compared it with that of the costameres and of the free sarcolemma. Tissue samples from normal rat and monkey hearts, and left ventricular tissue from normal and cardiomyopathic human hearts obtained at transplantation surgery were investigated using immunocytochemistry and confocal microscopy and by electron microscopy. In addition, we used a re-differentiation model of isolated, cultured adult rat cardiomyocytes. The cell membrane of the cardiac T-tubules was found to contain the cell-matrix focal adhesion molecules (FAMs) vinculin, talin, the α5β1 integrin and the membrane-associated proteins (MAPs) dystrophin and spectrin. FAMs and MAPs were localized in the T-tubular membrane in a similar pattern: in longitudinally oriented myocytes as transverse punctate lines at the Z-level; in transversally cut myocytes a radial tubular network was found to extend throughout the interior of the cell. Immunolabeling for basement membrane components including collagen IV, fibronectin and laminin showed a colocalization with FAMs and MAPs parallel to the transverse T-tubules. The costameres of the sarcolemma showed a protein composition resembling that of the T-tubules but the intervening segments of free sarcolemma showed absence of FAMs and presence of MAPs. For the first time, we demonstrate the existence and protein composition of the T-tubular scaffold in the human heart. Furthermore, we show that cardiomyocytes from human failing hearts have less abundant but more dilated T-tubules than do experimental animals. These results indicate that the cardiac T-tubular system contains a subcellular scaffold closely resembling that of the costameres. It consists of FAMs, MAPs and basal lamina proteins that confer structural integrity to the cardiac T-tubular membrane during contraction/relaxation cycles.
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    URL: http://dx.doi.org/10.1007/s004410051196
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  • 96
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    Chymotrypsin gene expression in rat peripheral organs (1998)
    Springer
    Cell & tissue research 292 (1998), S. 345-354 
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    ISSN: 1432-0878
    Keywords: Key words Pancreas ; Stomach ; Duodenum ; Ribonuclease protection assay ; Immunocytochemistry ; Protease ; Rat ; (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Prior studies have revealed the presence of chymotrypsinlike protease in peripheral organs, although no definitive evidence for the synthesis of this enzyme in tissue other than the pancreas is available. In an attempt to detect chymotrypsinogen mRNA in peripheral organs, a fragment of the pancreatic chymotrypsin mRNA from rat was amplified using PCR. The sequence was identified as a portion of the rat chymotrypsin B gene overlapping exon 5 through exon 7. It was subcloned into the pGEM-4Z vector and used as a template for the vitro transcription of an antisense riboprobe. Using ribonuclease protection and Northern blot analyses, chymotrypsin mRNA was detected in the rat pancreas, stomach, duodenum, ovary, and spleen. Monoclonal and polyclonal antisera against chymotrypsin detected chymotrypsinlike immunoreactivity in rat and human pancreas, rat stomach, duodenum and jejunum. Electrophoresis and immunoblotting revealed chymotrypsin-chymotrypsinogen bands (25–29 kDa) in the stomach and duodenum. Synthesis of a potent protease such as chymotrypsin in tissue other than pancreas is significant, suggesting a potential physiological and/or pathological role in these tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051065
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  • 97
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    Specific localization of gap junction protein, connexin45, in the deep muscular plexus of dog and rat small intestine (1998)
    Springer
    Cell & tissue research 292 (1998), S. 487-494 
    Details
    ISSN: 1432-0878
    Keywords: Key words Connexin ; Gap junctions ; Smooth muscle ; Intestinal pacemaker ; Confocal laser scanning microscope ; Dog ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Cellular networks of pacemaker activity in intestinal movements are still a matter of debate. Because gap-junctional intercellular communication in the intestinal wall may provide important clues for understanding regulatory mechanisms of intestinal movements, we have attempted to clarify the distribution patterns of three types of gap junction proteins. Using antibodies for connexin40, connexin43, connexin45, smooth muscle actin, and vimentin, immunocytochemical observations were made with the confocal laser scanning microscope on cryosections of fresh-frozen small intestine and colon of the dog and rat. Connexin 45 was localized along the deep muscular plexus of the small intestine in both dog and rat. Double labeling studies revealed that connexin45 overlapped with vimentin –, but not actin-positive areas, indicating the fibroblast-like nature of the cells, rather than their being smooth muscle-like. Connexin43 immunoreactivity appeared along the smooth muscle cell surface in the outer circular layer of the small intestine of both animals. Connexin 40 immunoreactivity was not observed in the muscle layer other than in the wall of large blood vessels. It is suggested that connexin45-expressing cells along the deep muscular plexus of dog and rat small intestine are likely to act as a constituent of a pacemaker system, which may include a conductive system, by forming a cellular network operating via specific types of gap junctions.
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    URL: http://dx.doi.org/10.1007/s004410051077
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  • 98
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    Calretinin-immunoreactive laminar nerve endings in the laryngeal mucosa of the rat (1998)
    Springer
    Cell & tissue research 292 (1998), S. 613-617 
    Details
    ISSN: 1432-0878
    Keywords: Key words Sensory nerve endings ; Calretinin ; Laryngeal mucosa ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of laminar nerve endings that contained immunoreactive calretinin was examined in the laryngeal mucosa of the adult rat. In whole-mount preparations, the immunoreactive laminar endings were distributed in the supraglottic region but not in the subglottic region. The laminar endings that arose from thick nerve fibers with or without swellings were identified as corpuscles with many variform terminal arborizations. They appeared to be located at the interface between the epithelium and the subepithelial connective tissue. The terminals were scattered under the basal lamina of the epithelium, and some of them were located within the epithelial layer. Immunoelectron microscopy revealed that both sub- and intraepithelial immunoreactive terminals that were filled with mitochondria were partly or totally ensheathed by Schwann cell processes. The denervation experiments, in which the superior laryngeal nerve was cut unilaterally or bilaterally, suggested that the laminar endings originate from the superior laryngeal nerve with strict ipsilateral innervation. The laminar endings might be associated with detection of changes in pressure in the laryngeal cavity or chemical stimuli.
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    URL: http://dx.doi.org/10.1007/s004410051091
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  • 99
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    A novel type of adhering junction in an epithelioid tumorigenic rat cell culture line (1998)
    Springer
    Cell & tissue research 294 (1998), S. 11-25 
    Details
    ISSN: 1432-0878
    Keywords: Key words Adhering junctions ; Desmosomes ; Endothelial junctions ; Plaque proteins ; Desmoplakin ; Cadherins ; Protein ZO-1 ; Rat ; cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Two major types of plaque-bearing adhering junctions are commonly distinguished: the actin microfilament-anchoring adhaerens junctions (AJs) and the desmosomes anchoring intermediate-sized filaments (IFs). Both types of junction usually possess the common plaque protein, plakoglobin, whereas the other plaque proteins and the transmembrane cadherins are mutually exclusive. For example, AJs contain E-, N-, or P-cadherin in combination with α- and β-catenin, vinculin and α-actinin, whereas in desmosomes, desmogleins and desmocollins are associated with desmoplakin and one or several of the plakophilins (PP1–3). Here we describe a novel type of adhering junction comprising proteins of both AJs and desmosomes and the tight junction (TJ) plaque protein, ZO-1, in a newly established, liver-derived tumorigenic rat cell line (RMEC-1). By immunofluorescence microscopy, cell-cell contacts are characterized by mostly continuous-appearing lines which are usually resolved by electron microscopy as extended arrays of closely spaced small plaque subunits. These plaque-covered regions are positive for plakoglobin, α- and β-catenin, the arm-repeat protein p120, vinculin, desmoplakin and protein ZO-1. They are positive for E-cadherin in cultures early on in passaging, but tend to turn negative for all known cadherins in densely grown cultures. On immunoblotting SDS-PAGE-separated proteins from dense-grown cell monolayers, “pan-cadherin” antibodies have reacted with a band at ∼140 kDa, identified as N-cadherin by peptide fingerprinting of the immunoprecipitated protein, which for reasons not yet clear is modified or masked in immunolocalization experiments. The exact histological derivation of RMEC-1 cells is not known. However, the observations of several endothelial markers and the fact that all cells are rich in IFs containing vimentin and/or desmin, while only subpopulations also reveal IFs containing CKs 8 and 18, is suggestive of a mesenchymal, probably endothelial origin. We discuss the molecular relationship of this novel type of extended junction with other types of adhering junctions.
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    URL: http://dx.doi.org/10.1007/s004410051152
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  • 100
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    Effects of growth rate and cell density on nerve growth factor secretion in cultures of vascular and bladder smooth muscle cells from hypertensive and hyperactive rats (1998)
    Springer
    Cell & tissue research 294 (1998), S. 431-438 
    Details
    ISSN: 1432-0878
    Keywords: Key words Nerve growth factor ; Hypertension ; Contact inhibition ; Proliferation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Elevated target-derived smooth muscle nerve growth factor (NGF) and resultant neurogenic plasticity are associated with both hypertension and hyperactive voiding in spontaneously hypertensive rats (SHRs: hypertensive, behaviorally hyperactive). In culture, vascular (VSMCs) and bladder (BSMCs) smooth muscle cells derived from SHRs secrete higher levels of NGF, proliferate more rapidly, and achieve higher density at confluence than do control Wistar-Kyoto (WKY) cells. To elucidate growth-related contributions to the elevated tissue NGF observed in SHRs, we examined vascular VSMC and BSMC NGF secretion in two inbred cell lines (WKHTs, hypertensive; WKHAs, hyperactive) derived from SHRs and WKYs to assess the phenotypic association of altered NGF metabolism with either hypertension or behavioral hyperactivity. Cell density, rather than growth rates, was the most important factor with respect to NGF secretion. VSMC density varied such that WKHT=SHR〉WKY= WKHA, higher VSMC density being associated with higher NGF output. However, in BSMC cultures, NGF output was the lowest in high density cell lines, with WKHT〉SHR〉WKY〉WKHA. SHR BSMCs had the second highest cell density and NGF secretion level. Elevated packing density, presumably because of a lack of contact inhibition, co-segregated with the hypertensive phenotype in both VSMCs and BSMCs. Thus, dysfunctional smooth muscle growth characteristics may contribute to the augmented vascular and bladder NGF content associated with high blood pressure and hyperactive voiding in SHRs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051194
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