ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Drosophila
  • Springer  (151)
  • PANGAEA
  • MDPI Publishing
  • 1995-1999  (151)
Collection
Keywords
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050256
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050269
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050266
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009648724937
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050942
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380051124
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003509802181
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003815626258
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Genomic P elements and P-M characteristics of eastern Australian populations of Drosophila melanogaster (1999)
    Springer
    Genetica 106 (1999), S. 231-245 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003918417012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    How valuable are model organisms for transposable element studies? (1999)
    Springer
    Genetica 107 (1999), S. 103-111 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003933419159
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Evidence for genomic regulation of the telomeric activity in Drosophila melanogaster (1999)
    Springer
    Genetica 107 (1999), S. 95-102 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003911925791
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Molecular domestication – more than a sporadic episode in evolution (1999)
    Springer
    Genetica 107 (1999), S. 197-207 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004070603792
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003591726851
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003957606743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Transposable elements and genome evolution: the case of Drosophila simulans (1999)
    Springer
    Genetica 107 (1999), S. 113-120 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003937603230
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009245712709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009297729547
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003762826116
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    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 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003712619487
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003718520490
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006906419110
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006976524916
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021494023660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021648103496
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006691431658
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050144
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050151
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Induction by alkaloids and phenobarbital of Family 4 Cytochrome P450s in Drosophila : evidence for involvement in host plant utilization (1998)
    Springer
    Molecular genetics and genomics 259 (1998), S. 54-59 
    Details
    ISSN: 1617-4623
    Keywords: Key words Cytochrome P450 ; Toxin resistance ; Multigene family ; Induction ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vertebrates, cytochrome P450s of the CYP2 and CYP3 families play a dominant role in drug metabolism, while in insects members of the CYP6 and CYP28 families have been implicated in metabolism of insecticides and toxic natural plant compounds. A degenerate 3′ RACE strategy resulted in the identification of fifteen novel P450s from an alkaloid-resistant species of Drosophila. The strong (17.4-fold) and highly specific induction of a single gene (CYP4D10) by the toxic isoquinoline alkaloids of a commonly utilized host-plant (saguaro cactus) provides the first indication that members of the CYP4 family in insects may play an important role in the maintenance of specific insect-host plant relationships. Strong barbiturate inducibility of CYP4D10 and two other D. mettleri P450 sequences of the CYP4 family was also observed, suggesting a pattern of xenobiotic responsiveness more similar to those of several vertebrate drug-metabolizing enzymes than to putative vertebrate CYP4 homologs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050788
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003043814761
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020906815133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022398809881
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Some evolutionary consequences of deleterious mutations (1998)
    Springer
    Genetica 102-103 (1998), S. 3-19 
    Details
    ISSN: 1573-6857
    Keywords: mutation rate ; selection ; self-fertilization ; Y chromosomes ; genetic recombination ; Drosophila ; flowering plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most mutations with observable phenotypic effects are deleterious. Studies of Drosophila and inbred plant populations suggest that a new individual may have a mean number of new deleterious mutations that exceeds one-half. Most of these have relatively small homozygous effects and reduce fitness by 1–2% when heterozygous. Several striking features of present-day organisms have apparently evolved in response to the constant input of deleterious alleles by recurrent mutation. For example, the adaptations of hermaphroditic organisms for outcrossing have been widely interpreted in terms of the benefits of avoiding the reduced fitness of inbred progeny, which is partly due to deleterious mutations. Population genetic models of modifiers of the breeding system in the presence of genome-wide deleterious mutation are reviewed and their predictions related to genetic and comparative data. The evolution of degenerate Y chromosomes is a phenomenon that may be caused by the accumulation of deleterious mutations. The population genetic mechanisms that can drive this degeneration are reviewed and their significance assessed in the light of available data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017066304739
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Mutation and evolution of microsatellites in Drosophila melanogaster (1998)
    Springer
    Genetica 102-103 (1998), S. 359-367 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; microsatellites ; mutation rate ; recombination ; gvariation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Levels of nucleotide polymorphism in the Drosophila melanogaster genome are correlated with rates of recombination. This relationship may be due to hitchhiking of advantageous mutations (selective sweeps) or to continual removal of deleterious mutations from the genome (background selection). One test of the relative contributions of selective sweeps and background selection to the observed levels of variation in the genome of D. melanogaster is to compare levels of nucleotide variability (with a mutation rate on the order of 10-9 per nucleotide per generation) with more rapidly evolving DNA loci such as microsatellites. This test depends critically on details of the mutational process of microsatellites. In this paper, we summarize our studies of microsatellite characteristics and mutation rates in D. melanogaster. We find that D. melanogaster microsatellites are short and have a mutation rate (6.5 × 10-6 per locus per generation) several orders of magnitude lower than mammals studied to date. We further show that genetic variation at 18 dinucleotide repeat microsatellites in a population of D. melanogaster from Maryland is correlated with regional rates of recombination. These and other microsatellite data suggest that both background selection and selective sweeps may contribute to the correlation between DNA sequence variation and recombination in Drosophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017083025154
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Environment-influenced expression of polygene mutations isolated from a natural population of Drosophila melanogaster (1998)
    Springer
    Genetica 102-103 (1998), S. 217-228 
    Details
    ISSN: 1573-6857
    Keywords: genotype × environment interaction ; QTLs ; polygenes ; Drosophila ; bristles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quantitative trait loci (QTLs) affecting sternopleural bristle number in Drosophila melanogaster have been mapped using phenotypic markers and progeny testing. The loci were found on four of the third chromosomes isolated from a natural population. All four loci showed large effects at the standard 25 °C culture temperature, but they responded in different ways when developmental temperature was lowered or raised. These data support the hypothesis that genotype × environment interactions have important influences on polygene expression, and some loci might be silent, or phenotypically neutral, under some conditions but play a large phenotypic role under others. Thus, a full cataloging of the loci contributing to mutational variance for QTLs cannot be done at just a single, controlled environmental condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017046001047
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Enigma of Y chromosome degeneration: Neo-Y and Neo-X chromosomes of Drosophila miranda a model for sex chromosome evolution (1998)
    Springer
    Genetica 102-103 (1998), S. 409-420 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; sex chromosomes ; Y chromosome degeneration ; Y chromosome mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome degeneration is characterized by structural changes in the chromosome architecture and expansion of genetic inertness along the Y chromosome. It is generally assumed that the heteromorphic sex chromosome pair has developed from a pair of homologues. Several models have been suggested. We use the unique situation of the secondary sex chromosome pair, neo-Y and neo-X (X2), in Drosophila miranda to analyze molecular mechanisms involved in the evolutionary processes of Y chromosome degeneration. Due to the fusion of one of the autosomes to the Y chromosome (about 2 Mya), a neo-Y chromosome and a neo-X chromosome, designated X2, were formed. Thus, formerly autosomal genes are inherited now on a pair of sex chromosomes in D. miranda. Analyzing DNA sequences from the X2 and neo-Y region, we observed a massive accumulation of DNA insertions on the neo-Y chromosome. From the analysis of several insertion elements, we present compelling evidence that the first step in Y chromosome degeneration is driven by the accumulation of transposable elements, especially retrotransposons. An enrichment of these elements along an evolving Y chromosome could account for the switch from a euchromatic into a heterochromatic chromatin structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017058119760
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Pattern of Chromosomal Localization of the Hoppel Transposable Element Family in the Drosophila melanogaster Subgroup (1998)
    Springer
    Chromosome research 6 (1998), S. 385-396 
    Details
    ISSN: 1573-6849
    Keywords: centromere ; Drosophila ; heterochromatin ; Hoppel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated a Hoppel-like transposon from heterochromatin of the second chromosome of Drosophila melanogaster and used a conserved DNA sequence between the different elements of this family to determine their distribution in both mitotic and polytene chromosomes. The hybridization pattern of polytene chromosomes extends throughout the entire chromocentre, as well as a substantial portion of the fourth chromosome. Analysis of different wild-type strains of D. melanogaster shows variation in euchromatic insertion sites, although most insertions are found near the chromocentre. The positions and the number of heterochromatic clusters of Hoppel on mitotic chromosomes are conserved among the several strains analysed. Accurate mapping of this element was achieved by in situ hybridization on D. melanogaster mitotic chromosomes that had previously been banded with Hoechst 33258. To evaluate the evolutionary stability of this pattern, different species were analysed by in situ hybridization and Southern blotting. We conclude that Hoppel has a conserved distribution in mitotic heterochromatin within the D. melanogaster subgroup, established around 5 million years ago. The overall conservation of heterochormatic organization supports the notion that heterochormatin does perform important structural and functional roles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009277322626
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    The molecular clock revisited: the rate of synonymous vs. replacement change in Drosophila (1998)
    Springer
    Genetica 102-103 (1998), S. 369-382 
    Details
    ISSN: 1573-6857
    Keywords: protein evolution ; Drosophila ; synonymous ; nonsynonymous ; Index of Dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of synonymous and nonsynonymous substitution were investigated for 24 genes in three Drosophila species, D. pseudoobscura, D. subobscura, and D. melanogaster. D. pseudoobscura and D. subobscura, two distantly related members of the obscura clade, differ on average by 0.29 synonymous nucleotide substitutions per site. D. melanogaster differs from the two obscura species by an average of 0.81 synonymous substitutions per site. Using a method developed by Gillespie, we investigated the variance to mean ratio, or Index of Dispersion, R, of substitutions along the three species' branches to test the fundamental prediction of the neutral theory of molecular evolution, E(R) = 1. For nonsynonymous substitutions, the average R, Ra is 1.6, which is not significantly different from the neutral theory prediction. Only 5 of the 24 genes had significantly large Ra valves, and 12 of the genes had Ra estimates of less than one. In contrast, the Index of Dispersion for synonymous substitutions was significantly large for 12 of the 24 genes, with an average of Rs = 4.4, also statistically significant. These findings contrast with results for mammals, which showed overdispersion of nonsynonymous substitutions, but not of synonymous substitutions. Weak selection acting to maintain codon bias in Drosophila, but not in mammals, may be important in explaining the high variance in the rate of synonymous substitutions in this group of organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017035109224
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020954731063
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006868306735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009201824806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    How Does Offspring Quality Change with Age in Male Drosophila Melanogaster? (1998)
    Springer
    Behavior genetics 28 (1998), S. 395-402 
    Details
    ISSN: 1573-3297
    Keywords: Sexual selection ; age ; fitness ; good genes ; mate choice ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract We examined the relationship of genetic quality to age in male Drosophila melanogaster to test two contrasting hypotheses. The traditional hypothesis is that older males have proven their viability and therefore produce offspring of superior genetic quality. This hypothesis is often evoked as an explanation for female preference for older mates. In contrast, we have recently argued that older fathers may produce offspring of inferior genetic quality. Here, we present results from an experiment designed to measure the genetic quality of offspring produced by 2 day old, 2 week old and 5 week old male D. melanogaster. We found a statistically significant small reduction in larval viability and a similar but statistically non-significant reduction in son mating ability among the offspring of the 5 week old males. Daughter fecundity showed no apparent trend for a reduction nor an increase in performance with increasing age of the fathers. There was no evidence of a difference between the 2 day old and the 2 week old males for any of these three fitness components. These results are in somewhat better accordance with our alternative hypothesis, but the relatively weak and late occurring effects indicate that mate choice based on age may not be a viable strategy in this population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021677804038
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Developmental Isolation and Subsequent Adult Behavior of Drosophila paulistorum.IV. Courtship (1998)
    Springer
    Behavior genetics 28 (1998), S. 57-65 
    Details
    ISSN: 1573-3297
    Keywords: Courtship ; sexual selection ; sexual isolation ; semispecies ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Early social experiences play important roles in adult Drosophila paulistorummate selection. Differences in courtship between control males and wholly socially isolated males were observed in chambers. Socially isolated males displayed more courtship toward virgin females than did controls. Socially isolated males were more successful in competing for mates. Yet socially isolated males from all six semispecies also displayed notable frequencies of homosexual behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021460832378
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Doxycycline-induced transgene expression during Drosophila development and aging (1998)
    Springer
    Molecular genetics and genomics 258 (1998), S. 571-579 
    Details
    ISSN: 1617-4623
    Keywords: Key words Tetracycline repressor ; Inducible promoter ; Drosophila ; Aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The “reverse” tetracycline repressor (rtR) binds a specific DNA element, the tetracycline operator (tetO), only in the presence of tetracycline, or derivatives such as doxycycline (dox). Fusion of rtR to the transcriptional activation domain of herpes virus protein VP16 produces a eukaryotic transactivator protein (rtTA). rtTA has previously been shown to allow dox-dependent transcription of transgenes linked to tetO sequences in mammals. To adapt this system to Drosophila, the Actin5C promoter was used to drive constitutive expression of rtTA in transgenic flies. Three reporter constructs, each encoding E. coli β-galactosidase (β-gal), were also introduced into transgenic flies. In one reporter seven tetO sequences were fused to the Adh core promoter. The other two reporter constructs contain seven tetO sequences fused to the hsp70 core promoter. Feeding of transgenic Drosophila containing the rtTA construct and any one of the three reporter constructs with dox caused up to 100-fold induction of β-gal. Dox induced β-gal expression in all tissues, in larvae and in young and senescent adults. Induction of β-gal in adults had no detectable effect on life span. These results suggest the potential usefulness of this system for testing specific genes for effects on Drosophila development and aging.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050770
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002650050427
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Lineage and fate in Drosophila: role of the gene tramtrack in sense organ development (1997)
    Springer
    Development genes and evolution 207 (1997), S. 97-106 
    Details
    ISSN: 1432-041X
    Keywords: Key words Cell fate determination ; Cell lineage ; Drosophila ; Peripheral nervous system ; Tramtrack
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The tactile bristles of the fly comprise four cells that originate from a single precursor cell through a fixed lineage. The gene tramtrack (ttk) plays a crucial role in defining the fates of these cells. Here we analyse the normal pattern of expression of ttk, as well as the effect of ttk overexpression at different steps of the lineage. We show that ttk is never expressed in cells having a neural potential, and that in cells where ttk is expressed, there is a delay between division and the onset of expression. The ectopic expression of ttk before some stage of the cell cycle can block further cell division. Furthermore, this expression transforms neural into non-neural cells, suggesting that ttk acts as a repressor of neural fate at each step of the lineage. Our results suggest that ttk is probably not involved in setting up the mechanism that creates an asymmetry between sister cells, but rather in the implementation of that choice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050096
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Requirement of teashirt (tsh) function during cell fate specification in developing head structures in Drosophila (1997)
    Springer
    Development genes and evolution 207 (1997), S. 137-146 
    Details
    ISSN: 1432-041X
    Keywords: Key words teashirt ; Antennapedia ; Eye-antennal discs ; Drosophila ; Homeosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The homeotic gene teashirt (tsh) is known to regulate segmental identity of the trunk region of the Drosophila embryo. Here we report a requirement for tsh function in the development of adult head structures. Animals homozygous for a viable tsh allele or heterozygous for various embryonic recessive lethal alleles displayed miniaturized maxillary palps, a phenotype characteristically induced by dominant gain-of-function mutations of Antennapedia (Antp) homeotic gene. Animals transheterozygous for tsh and Antp mutations displayed an enhanced antenna-to-leg and a striking reduced-eye phenotype suggesting aggravated ANTP misexpression in eye-antennal discs of these animals. In agreement with this, in the developing eye-antennal discs of the tsh mutant animals a significant amount of ANTP protein was detected overlapping the domains where tsh is normally expressed. These results suggest that tsh specifies adult head segments by repressing Antp expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    G2 arrest of cell cycle ensures a determination process of sensory mother cell formation in Drosophila (1997)
    Springer
    Development genes and evolution 207 (1997), S. 199-202 
    Details
    ISSN: 1432-041X
    Keywords: Key words Cell cycle ; Determination ; Sensory mother cell ; Cyclin A ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In Drosophila, the sensory mother cells of macrochaetes are chosen from among the mitotically quiescent clusters of cells in wing imaginal discs, where other cells are proliferating. The pattern of cyclin A, one of the G2 cyclins, reveals that mitotically quiescent clusters of cells are arrested in G2. When precocious mitoses are induced during sensory mother cell determination by the ectopic expression of string, a known G2/M transition regulator, the formation of sensory mother cells is disturbed, resulting in the loss of macrochaetes in the adult notum. This suggests that G2 arrest of the cell cycle ensures the proper determination of sensory mother cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Early development of the Drosophila mushroom bodies, brain centres for associative learning and memory (1997)
    Springer
    Development genes and evolution 207 (1997), S. 242-252 
    Details
    ISSN: 1432-041X
    Keywords: Key words Mushroom bodies ; Kenyon cells ; Enhancer-trap ; GAL4 ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have studied the formation of Drosophila mushroom bodies using enhancer detector techniques to visualize specific components of these complex intrinsic brain structures. During embryogenesis, neuronal proliferation begins in four mushroom body neuroblasts and the major axonal pathways of the mushroom bodies are pioneered. During larval development, neuronal proliferation continues and further axonal projections in the pedunculus and lobes are formed in a highly structured manner characterized by spatial heterogeneity of reporter gene expression. Enhancer detector analysis identifies many genomic locations that are specifically activated in mushroom body intrinsic neurons (Kenyon cells) during the transition from embryonic to postembryonic development and during metamorphosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050112
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    The Hermes element from Musca domestica can transpose in four families of cyclorrhaphan flies (1997)
    Springer
    Genetica 99 (1997), S. 15-29 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; Musca ; recombination ; transgenics ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic insect technology will provide opportunities to explore the basic biology of a broad range of insect species in ways that will prove insightful and important. It is also a technology that will provide opportunities to manipulate the genotypes of insects of practical significance to the health and welfare of humans. The Hermes transposable element from the housefly, Musca domestica, is a short inverted repeat-type element related to hobo from Drosophila melanogaster, Ac from Zea mays, and Tam3 from Antirrhinum majus. It has potential to become a versatile and efficient broad host-range insect transformation vector. The ability of Hermes to transpose when introduced into five species of diptera from four divergent families was tested using an in vivo, interplasmid transpositional recombination assay. Hermes was capable of transposing in all species tested, demonstrating that Hermes has a broad host-range. In addition, the rates of transposition were sufficiently high in all species tested to suggest that Hermes will be an efficient gene transfer vector in a wide range of insect species. The Hermes element also revealed a pattern of integration into the target substrate that permitted factors determining integration site selection to be identified. Primary nucleotide sequence of the integration site played a role as did proximity to preferred integration sites and the nucleosomal organization of the target.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018349803656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Non-linear selection response in Drosophila: a strategy for testing the rare-alleles model of quantitative genetic variability (1997)
    Springer
    Genetica 99 (1997), S. 59-66 
    Details
    ISSN: 1573-6857
    Keywords: artificial selection ; Drosophila ; genetic variation ; non-linear response ; rare alleles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quantitative genetic theory predicts that variation due to rare alleles at many loci will generate a transient acceleration in the response to directional selection. We have tested this prediction by constructing experimental lines of Drosophila melanogaster that carry positively selected ethanol resistance alleles at low frequencies, and then subjecting the lines to directional selection for ethanol resistance. Approximately 468,000 files were subjected to artificial selection over 30 generations. The predicted non-linear selection responses were observed in all experimental lines and replicates, on three genetic backgrounds. In contrast, un-selected controls and lines carrying random alleles at low frequencies on the same genetic backgrounds exhibited linear selection responses. These results demonstrate that non-linearities due to rare alleles are detectable and repeatable, provided that experiments are done on a sufficiently large scale. The results suggest that it may be possible to test for rare-alleles as a component of naturally occurring genetic variation by careful examination of selection response curves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018390313864
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    TheHermes element fromMusca domestica can transpose in four families of cyclorrhaphan flies (1997)
    Springer
    Genetica 99 (1997), S. 15-29 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; Musca ; recombination ; transgenics ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic insect technology will provide opportunities to explore the basic biology of a broad range of insect species in ways that will prove insightful and important. It is also a technology that will provide opportunities to manipulate the genotypes of insects of practical significance to the health and welfare of humans. TheHermes transposable element from the housefly,Musca domestica, is a short inverted repeat-type element related tohobo fromDrosophila melanogaster, Ac fromZea mays, andTam3 fromAntirrhinum majus. It has potential to become a versatile and efficient broad host-range insect transformation vector. The ability ofHermes to transpose when introduced into five species of diptera from four divergent families was tested using anin vivo, interplasmid transpositional recombination assay.Hermes was capable of transposing in all species tested, demonstrating thatHermes has a broad host-range. In addition, the rates of transposition were sufficiently high in all species tested to suggest thatHermes will be an efficient gene transfer vector in a wide range of insect species. TheHermes element also revealed a pattern of integration into the target substrate that permitted factors determining integration site selection to be identified. Primary nucleotide sequence of the integration site played a role as did proximity to preferred integration sites and the nucleosomal organization of the target.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259495
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Enzymatic responses of Drosophila melanogaster to long- and short-term exposures to ethanol (1997)
    Springer
    Molecular genetics and genomics 255 (1997), S. 258-268 
    Details
    ISSN: 1617-4623
    Keywords: Key words Alcohol dehydrogenase ; Drosophila ; Ethanol exposure ; Larva-to-pupa survival ; Metabolic response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of environmental ethanol on larva-to-pupa survival and on the activities of four enzymes were investigated in three Drosophila melanogaster strains. The strains had different allelic combinations at the Odh and Aldox loci on their third chromosomes, but they all carried the Adh S -Gpdh F allelic combination on the second chromosome. Replicates of each of the strains were exposed to three different ethanol treatments: (i) no ethanol in the medium (control); (ii) 5% ethanol for a single generation (short-term exposure); (iii) 5% ethanol for 20 generations (long-term exposure). In all experiments, the activities of four enzymes (ADH, ODH, GPDH and AOX) were measured in larvae, pupae and adults. The results showed that (i) the larval and adult metabolic responses to environmental ethanol were different; (ii) enzyme activity changes under short-term exposure differed from those measured under long-term exposure; (iii) the activities of the allozymes common to all strains (ADH-S and GPDH-F), differed depending on the genetic background. Changes in larva-to-pupa survival were seen when the larvae of control and exposed lines of the three strains were confronted with various concentrations of ethanol. In all three strains, the exposed lines had significantly higher initial survival rate and ethanol tolerance than the control lines. Strain-specific differences were observed in the ethanol tolerance of both types of line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050496
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    A graphical method for analysing the dynamics of three-species systems (1997)
    Springer
    Oecologia 111 (1997), S. 529-534 
    Details
    ISSN: 1432-1939
    Keywords: Key words Competition ; Multi-species ; Dynamics ; Drosophila ; Triangular co-ordinates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report a series of experiments with three competing species and a novel graphical analysis that explores the dynamics of this simple multi-species system. The three competing species (Drosophila hydei, D. immigrans and D. virilis) were maintained in five very large cages, on a natural fruit resource. The analytic method involved constructing a “dynamic surface”, by interpolation, from the population trajectories. Within the dynamic surface constructed from the five experiments a small “equilibrium area” (an area of point vectors) could be identified. The implications of both the method and the results are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050267
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Constitutive heterochromatin and transposable elements in Drosophila melanogaster (1997)
    Springer
    Genetica 100 (1997), S. 85-93 
    Details
    ISSN: 1573-6857
    Keywords: heterochomatin ; transposable elements ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several families of transposable elements (TEs), most of them belonging to the retrotransposon catagory, are particularly enriched in Drosophila melanogaster constitutive heterochromatin. The enrichment of TE-homologous sequences into heterochromatin is not a peculiar feature of the Drosophila genome, but appears to be widespread among higher eukaryotes. The constitutive heterochromatin of D. melanogaster contains several genetically active domains; this raises the possibility that TE-homologous sequences inserted into functional heterochromatin compartments may be expressed. In this review, I present available data on the genetic and molecular organization of D. melanogaster constitutive heterochromatin and its relationship with transposable elements. The implications of these findings on the possible impact of heterochromatic TEs on the function and evolution of the host genome are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018304922862
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Molecular domestication of mobile elements (1997)
    Springer
    Genetica 100 (1997), S. 261-270 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; insertion sequences ; P element ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements are ubiquitous in all organisms and represent a dynamic component of their genomes, causing mutations and thereby genetic variation. Because of their independent and expansive replication strategy, these elements are called selfish and were thought to have no impact on the adaptive evolution of their host organisms. Although most TE-induced mutations seem to exert only negative effects on the fitness of their carrier, recent evidence indicates that in the course of evolution at least some TE-mediated changes have become established features of the host genome. For example, the insertion of TEs may provide novel cis-regulatory regions to preexisting host genes or TE-derived trans-acting factors may undergo a molecular transition into novel host genes through a process described as molecular domestication. The stationary P element related gene clusters of D. guanche, D. madeirensis and D. subobscura provide an excellent model system to study the evolutionary impact of TEs on genome evolution. Each cluster unit consists of a cis-regulating section composed of different insertion sequences followed by the first three exons of a P element that are coding for a 66 kDa ‘repressor-like’ protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018306317836
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Genomic distribution of the retrovirus-like element ZAM in Drosophila (1997)
    Springer
    Genetica 100 (1997), S. 131-140 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; FISH on Drosophila chromosomes ; genomic distribution ; retrotransposons retrovirus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mobile element ZAM, recently identified in Drosophila melanogaster, is similar in structure and coding potential to vertebrate retroviruses. In this paper, we analyze the insertional and structural polymorphism of this element and show that members of this family appear to have a long evolutionary history in the genome of Drosophila. It is present in all the species of the D. melanogaster subgroup and in more distantly related species like D. takahashii, D. ananassae, or D. virilis but in a lower copy number or with a lower homology. Two categories of strains have been previously identified in D. melanogaster: strains with a high copy number of ZAM and strains with a low copy number. Here, we show that ZAM is at least in a low copy number in each tested strain of the species analyzed. The study of ZAM's genomic distribution by FISH mapping analysis to salivary gland polytene chromosomes or on mitotic chromosomes indicates that most of the insertion sites of ZAM elements are associated with the constitutive heterochromatin regardless of the ZAM copy number. In addition, our results suggest that multiple ZAM elements are present at the insertion sites visualized by in situ experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018317209658
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Evidence for a host role in regulating the activity of transposable elements in Drosophila melanogaster: the case of the persistent instability of Bari 1 elements in Charolles stock (1997)
    Springer
    Genetica 100 (1997), S. 149-154 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; transposons ; de novo insertions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most reports in which the activity of numerous Drosophila transposon families has been studied, only a subset of the families tested appears mobile. A comparison of these data shows that there are no transposons inherently more unstable than others and suggests that host factors regulate the activity of transposable elements. Consistent with this conclusion are the properties of Bari 1 elements, which are the only ones of the 14 families tested to be unstable in Charolles stock. Instability is persistent over 53 generations and appears to affect recurrent insertion sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018325427405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Maintenance of transposable element copy number in natural populations of Drosophila melanogaster and D. simulans (1997)
    Springer
    Genetica 100 (1997), S. 161-166 
    Details
    ISSN: 1573-6857
    Keywords: transposable elements ; populations ; Drosophila ; copy number regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate the main forces controlling the containment of transposable elements (TE) in natural populations, we analyzed the copia, mdg1, and 412 elements in various populations of Drosophila melanogaster and D. simulans. A lower proportion of insertion sites on the X chromosome in comparison with the autosomes suggests that selection against the detrimental effects of TE insertions is the major force containing TE copies in populations of Drosophila. This selection effect hypothesis is strengthened by the absence of the negative correlation between recombination rate and TE copy number along the chromosomes, which was expected under the alternative ectopic exchange model (selection against the deleterious rearrangements promoted by recombination between TE insertions). A cline in 412 copy number in relation to latitude was observed among the natural populations of D. simulans, with very high numbers existing in some local populations (around 60 copies in a sample from Canberra, Australia). An apparent absence of selection effects in this Canberra sample and a value of transposition rate equal to 1–2 × 10-3 whatever the population and its copy number agree with the idea of recent but temporarily drastic TE movements in local populations. The high values of transposition rate in D. simulans clearly disfavor the hypothesis that the low amount of transposable elements in this species could result from a low transposition rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018329528314
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Specific induction of the hsrω locus of Drosophila melanogaster by amides (1997)
    Springer
    Chromosome research 5 (1997), S. 359-362 
    Details
    ISSN: 1573-6849
    Keywords: amides ; Drosophila ; heat shock ; 93D locus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report here that 3-aminobenzamide and other amides, such as formamide, acetamide and nicotinamide, specifically induce a high rate of transcription at the 93D puff (the hsrω heat shock gene) in polytene chromosomes of Drosophila melanogaster. Other chemicals, such as benzamide, colchicine, thiamphenicol and paracetamol, that are already known to specifically induce transcription at the hsrω locus are also identified as amides. In view of the specific induction of the 93D puff by different amides and other data that demonstrate hsrω transcription in response to benzamide and colchicine etc. to be independent of its heat shock induction, it appears likely that amides induce this locus through distinct regulatory elements that we propose to designate amide response elements (AREs).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018440224177
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Population genetics models of transposable elements (1997)
    Springer
    Genetica 100 (1997), S. 281-294 
    Details
    ISSN: 1573-6857
    Keywords: copy number ; Drosophila ; inbreeding ; population genetics ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The control of transposable element copy number is of considerable theoretical and empirical interest. Under simple models, copy numbers may increase without limit. Mechanisms that can prevent such an increase include those in which the effect of selection increases with copy number, those in which the rate of transposition decreases with copy number, and those where unlimited increase in copy number is prevented by the consequences of functional heterogeneity in the transposable element family. Finite population sizes may attenuate the power of natural selection to act on transposable element copy number in a number of ways that may be of particular importance in laboratory populations. First, a small host population size will create occasional periods in which the variance between individuals in copy number is diminished, and with it the power of natural selection, even when the expected variance is Poisson. Second, small population sizes will produce high-frequency transposable element sites, systematically reducing the variance in copy number. The consequences will be particularly profound when the selective damage of transposable elements follows from their heterozygosity, as when ectopic exchange limits copy number.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018310418744
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    A simulation of P element horizontal transfer in Drosophila (1997)
    Springer
    Genetica 100 (1997), S. 295-307 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; horizontal transfer ; invasion dynamics ; P transposable element ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experimental data suggest that the P transposable element has invaded the Drosophila melanogaster genome after a horizontal transfer from the phylogenetically distant species Drosophila willistoni. The differences between P element phylogeny and that of the Drosophila genus could in part be explained by horizontal transfers. In vivo experiments show that P elements are able to transpose in the genomes of other Drosophila species. This suggests that horizontal transmission of P elements could have taken place in many species of this genus. The regulation, transposition, and deleterious effects of the P element in D. melanogaster were formalized and integrated in a global model to produce a simulation program that simulates a P element invasion. The simulations show that our knowledge of the P element in D. melanogaster can explain its behavior in the Drosophila genus. The equilibrium state of the invaded population of a new species depends on its ability to repair damage caused by P element activity. If repair is efficient, the equilibrium state tends to be of the P type state, in which case the element could subsequently invade other populations of the species. Conversely, the equilibrium state is of the M′ type state when the ability to repair damage is low. The invasion of the P element into other populations of this new species can then only occur by genetic drift and it is likely to be lost. The success of a P element invasion into a new species thus greatly depends on its ability to produce dysgenic crosses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018362402815
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Distribution of transposable elements in neotropical species of Drosophila (1997)
    Springer
    Genetica 101 (1997), S. 153-165 
    Details
    ISSN: 1573-6857
    Keywords: transposable elements ; Drosophila ; gypsy ; hobo ; P element ; mariner ; I element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phylogenetic distribution of transposable families, P, gypsy, hobo, I, and mariner has been analyzed in 33 species of 11 groups of neotropical Drosophila and a Drosophilidae species Zygotrica vittimaculosa, using squash blot and dot blot. Genomic DNA of almost all neotropical species tested hybridized with gypsy probe and some species showed a particularly strong hybridization signal, as D. gaucha, D. virilis, and species of flavopilosa group. The hobo element was restricted to melanogaster group and some strains of D. willistoni. Only D. simulans DNA showed hybridization to mariner probe in all species tested and D. simulans and D. melanogaster showed hybridization with I element probe. P element homologous sequence was present in D. melanogaster and all species and strains of the willistoni and saltans groups tested. The presence of at least one P-homologous sequence was detected in Drosophila mediopunctata. This one was the only P-bearing species of all six tested from the tripunctata group. Four different pairs of primers homologous to segments of the canonical sequence of D. melanogaster's P were used to amplify specific sequences from D. mediopunctata DNA, showing the occurrence of seemingly well-conserved P-homologous sequences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018381104700
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    A Comparison of Female Postcopulatory Behavior in Drosophila melanogaster and Drosophila biarmipes (1997)
    Springer
    Journal of insect behavior 10 (1997), S. 761-770 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; females ; sex appeal ; sexual receptivity ; fecundity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The postcopulatory behavior of Drosophila biarmipes and Drosophila melanogaster females was analyzed and compared. Females from both species were shown to undergo a series of behavioral changes following mating, including significant reductions in both sexual attractiveness and receptivity. However, while both attractiveness and receptivity returned to “virgin-like” levels within a few days in D. melanogaster, D. biarmipes females, which regained their sexual attractiveness within a few days, remained unreceptive to copulation for at least 2 weeks. With respect to fecundity, D. melanogaster females produced more offspring when given opportunities to remate, while D. biarmipes females did not benefit from remating opportunities. These observations suggest that D. biarmipes females may have the ability to store sperm and produce offspring from a single mating over longer periods of time than other drosophilids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:JOIR.0000010411.79386.22
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Novel embryonic regulation of Ca2+-activated K+ channel expression inDrosophila (1997)
    Springer
    Invertebrate neuroscience 2 (1997), S. 283-291 
    Details
    ISSN: 1439-1104
    Keywords: Drosophila ; potassium channel ; slowpoke ; calcium-activated ; gene regulation ; embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Theslowpoke gene ofDrosophila melanogaster encodes a Ca2+-activated K+ channel that is expressed in neurons, muscles, tracheal cells and the middle midgut. The entire transcriptional control region ofslowpoke is contained in 11 kb of genomic DNA. Previous work has identified four different tissue-specific promoters (Promoters C1, C1b, C1c and C2) and sequences that regulate their activity. Here we describe and contrast the regulation of neuronal and muscle expression during embryogenesis with its regulation during larval and adult stages. Embryonic regulation is fundamentally different. The embryo uses Promoter C1 and a previously undescribed promoter, called Promoter Ce, to drive neuronal expression. The expression patterns of these promoters are distinct. Muscle expression arises from Promoter C2 as in other developmental stages. A downstream intronic region has been shown to contain control elements that modulate promoter activity differently in embryos, larvae and adults. Embryonic CNS expression is not dependent on the intron, however; its deletion has substantial effects on neuronal expression in larvae and adults. In embryonic muscle, removal of the intron eliminates muscle expression even though this deletion does not reduce larval muscle expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02211941
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Premating Isolation Is Determined by Larval Rearing Substrates in CactophilicDrosophila mojavensis. III. Epicuticular Hydrocarbon Variation Is Determined by Use of Different Host Plants inDrosophila mojavensis andDrosophila arizonae (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 2803-2824 
    Details
    ISSN: 1573-1561
    Keywords: Incipient speciation ; sexual selection ; mating behavior ; cuticular hydrocarbons ; cactus ; Sonoran Desert ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Adult epicuticular hydrocarbon profiles of male and femaleDrosophila mojavensis have been implicated as determinants of mate choice leading to premating isolation between geographically isolated populations. Hydrocarbon profiles of a Baja California and a mainland Sonora population ofDrosophila mojavensis, ayellow body mutant strain ofD. mojavensis, and a population ofD. arizonae were compared among flies that had been reared on two cactus substrates and a synthetic laboratory growth medium in order to assess the degree to which natural rearing substrates influence adult hydrocarbon composition. Twenty epicuticular hydrocarbon components, ranging from C29 to C41, were recovered by gas chromatography that represented major classes of alkanes, alkenes, and alkadienes. We found differences in relative amounts of epicuticular hydrocarbons among Baja and mainlandD. mojavensis, and theyellow body mutants. There were few differences betweenD. mojavensis andD. arizonae. The effects of rearing substrates were remarkable: most of the differences were due to the effects of lab food vs. cactus, but there were significant rearing substrate effects due to differences in the two cacti used. Eleven hydrocarbon components differed in abundance between males and females or showed significant sex × rearing substrate interactions from ANOVA. The effects of rearing substrates on epicuticular hydrocarbon composition inD. mojavensis are concordant with changes in the intensity of premating isolation between populations, implicating host ecology as a major determinant in patterns of mate choice in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022519228346
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Developmental stability and environmental stress in natural populations of Drosophila pachea (1997)
    Springer
    Ecotoxicology 6 (1997), S. 233-238 
    Details
    ISSN: 1573-3017
    Keywords: Developmental instability ; cactophilic ; Drosophila ; fluctuatingasymmetry ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We examined the relationship between developmental stress and fluctuating asymmetry in a natural population of Drosophila pachea, a cactophilic fruitfly. Cactus host variation was found to exert significant influence on the size of legs and of wings of emerging adults, but stressors associated with reduced size did not show the predicted increase in fluctuating asymmetry for either leg or wing length. These findings underscore questions raised by other investigators as to the broad utility of fluctuating asymmetry as a measure of environmental stress
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018678827931
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Ovulation and the Suppression of Mating in Drosophila melanogaster Females: Behavioral Basis (1997)
    Springer
    Behavior genetics 27 (1997), S. 483-488 
    Details
    ISSN: 1573-3297
    Keywords: Drosophila ; sex peptide ; ovulation ; mating suppression ; antiaphrodisiac pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Virgin females of Drosophila melanogaster that are ectopically expressing the sex-pep-tide gene show a high level of ovulation and are unreceptive to males. However, if they are genetically deprived of eggs, receptivity is considerably restored (Fuyama, 1995). These females, whether they have eggs or not, extrude their ovipositors toward courting males as frequently as do fertilized females. However, this rejection behavior was ineffective in suppressing male courtship. Of females with eggs, about half of them could suppress male courtship. Females lacking eggs could not suppress male courtship and continued to elicit vigorous courtship. This difference seems to account for the increased mating frequency in sterilized females. Courtship behavior by mutant males defective in olfaction or learning suggested that females are capable of repelling males by emitting a volatile pheromone(s) with an inhibitory effect on male courtship.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1025630602057
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Non-linear selection response inDrosophila: a strategy for testing the rare-alleles model of quantitative genetic variability (1997)
    Springer
    Genetica 99 (1997), S. 59-66 
    Details
    ISSN: 1573-6857
    Keywords: artificial selection ; Drosophila ; genetic variation ; non-linear response ; rare alleles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quantitative genetic theory predicts that variation due to rare alleles at many loci will generate a transient acceleration in the response to directional selection. We have tested this prediction by constructing experimental lines ofDrosophila melanogaster that carry positively selected ethanol resistance alleles at low frequencies, and then subjecting the lines to directional selection for ethanol resistance. Approximately 468,000 files were subjected to artificial selection over 30 generations. The predicted non-linear selection responses were observed in all experimental lines and replicates, on three genetic backgrounds. In contrast, un-selected controls and lines carrying random alleles at low frequencies on the same genetic backgrounds exhibited linear selection responses. These results demonstrate that non-linearities due to rare alleles are detectable and repeatable, provided that experiments are done on a sufficiently large scale. The results suggest that it may be possible to test for rare-alleles as a component of naturally occurring genetic variation by careful examination of selection response curves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259498
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Genetical analysis of visual system disorganizer (vid), a new gene involved in normal development of eye and optic lobe of the brain in Drosophila melanogaster (1997)
    Springer
    Genetica 99 (1997), S. 31-45 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; P-element mutagenesis ; somatic mosaics ; visual system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A neuroanatomical screening of a collection of P-element mutagenized flies has been carried out with the aim of finding new mutants affecting the optic lobe of the adult brain in Drosophila melanogaster. We have identified a new gene that is involved in the development of the adult axon array in the optic ganglia and in the ommatidia assembly. We have named this locus visual system disorganizer (vid). Reversional mutagenesis demonstrated that the vid mutant was the result of a P-element insertion in the Drosophila genome and allowed us to generate independent alleles, some of which resulted in semilethality, like the vid original mutant, while the others were completely lethal. A genetic somatic mosaic analysis indicated that the vid gene is required in the eye for its normal development by inductive effects. This analysis also suggests an inductive effect of the vid gene on the distal portion of the optic lobe, particularly the lamina and the first optic chiasma. Moreover, the absence of mutant phenotype in the proximal region of the optic ganglia, including the medulla, the second optic chiasma, and the lobula complex underlying mosaic eyes, is suggestive of an autonomously acting mechanism of the vid gene in the optic lobe. The complete or partial lethality generated by different mutations at the vid locus suggests that this gene's role may not be limited to the visual system, but may also affect a vital function during Drosophila development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018368613535
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Genetical analysis ofvisual system disorganizer (vid), a new gene involved in normal development of eye and optic lobe of the brain inDrosophila melanogaster (1997)
    Springer
    Genetica 99 (1997), S. 31-45 
    Details
    ISSN: 1573-6857
    Keywords: Drosophila ; P-element mutagenesis ; somatic mosaics ; visual system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A neuroanatomical screening of a collection of P-element mutagenized flies has been carried out with the aim of finding new mutants affecting the optic lobe of the adult brain inDrosophila melanogaster. We have identified a new gene that is involved in the development of the adult axon array in the optic ganglia and in the ommatidia assembly. We have named this locusvisual system disorganizer (vid). Reversional mutagenesis demonstrated that thevid mutant was the result of a P-element insertion in theDrosophila genome and allowed us to generate independent alleles, some of which resulted in semilethality, like thevid original mutant, while the others were completely lethal. A genetic somatic mosaic analysis indicated that thevid gene is required in the eye for its normal development by inductive effects. This analysis also suggests an inductive effect of thevid gene on the distal portion of the optic lobe, particularly the lamina and the first optic chiasma. Moreover, the absence of mutant phenotype in the proximal region of the optic ganglia, including the medulla, the second optic chiasma, and the lobula complex underlying mosaic eyes, is suggestive of an autonomously acting mechanism of thevid gene in the optic lobe. The complete or partial lethality generated by different mutations at thevid locus suggests that this gene's role may not be limited to the visual system, but may also affect a vital function duringDrosophila development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259496
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Terminal filament cell organization in the larval ovary of Drosophila melanogaster: ultrastructural observations and pattern of divisions (1996)
    Springer
    Development genes and evolution 205 (1996), S. 356-363 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Ovary morphogenesis ; Mitotic wave ; Pattern formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The adult ovary of Drosophila is composed of approximately twenty parallel repetitive structures called ovarioles. The ovarioles appear at the prepupal stage and their formation requires the presence of stacks of discshaped cells called the terminal filaments. Terminal filaments form in a progressive manner during the third larval instar. We have looked at the beginning of formation of both the terminal filaments and ovarioles at an ultrastructural level. Moreover, we studied the pattern of division of the terminal filament cell precursors using the base analog, BrdU. Two main waves of division are observed. The first wave consists of divisions of almost all the terminal filament cell precursors during a short period of time at the transition between the second and third larval instar. The second wave, in which the precursors carry out their final divisions before differentiating, occurs gradually, going from the medial to the lateral side of the ovary during the first half of the third larval instar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377215
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    The function of type IV collagen during Drosophila embryogenesis (1996)
    Springer
    Development genes and evolution 205 (1996), S. 468-475 
    Details
    ISSN: 1432-041X
    Keywords: Type IV collagen ; Drosophila ; Germ band retraction ; Dorsal closure ; Nerve cord condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A collagen gene (Dcg1) was characterized in Drosophila melanogaster and shown to encode a peptide related to vertebrate basement membrane type IV collagen chains. To study the function of type IV collagen during Drosophila development, we transformed flies with a partially truncated Dcg1 gene under the control of a heat-shock promotor. This construct induced synthesis of shortened pro-α chains which associated with normal ones and thereby caused degradation of the shortened and normal pro-α chains through a process called “pro-collagen suicide”. A large proportion of embryos expressing the transgene developed a phenotype exhibiting absence or partial retraction of the germ band with defects in nerve cord condensation and dorsal closure. Together these results indicated that, during embryogenesis, type IV collagen was an essential guiding factor for cell-matrix interactions in morphogenetic events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377228
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Tirant: A new retrotransposon-like element inDrosophila melanogaster (1996)
    Springer
    Journal of molecular evolution 42 (1996), S. 369-375 
    Details
    ISSN: 1432-1432
    Keywords: Transposable elements ; Drosophila ; Tirant ; Retrotransposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper we report a new retrotransposon-like element ofDrosophila melanogaster calledTirant. This sequence is moderately repeated in the genome of this species and it has been found to be widely dispersed throughout its distribution area. From Southern blot andin situ analyses, this sequence appears to be mobile inD. melanogaster, since its chromosome location and the hybridization patterns vary among the different strains analyzed. In this way, partial sequencing ofTirant ends suggests that it is a retrotransposon, since it is flanked by two LTRs. The presence of sequences homologous toTirant has been also investigated in 28 species of the genusDrosophila by means of Southern analyses. These sequences were only detected in species frommelanogaster andobscura groups. These data suggest that ancestral sequences ofTirant appeared after the Sophophora radiation and before the divergence of those groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02337547
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Evolution of the larval cuticle proteins coded by the secondary sex chromosome pair:X2 andneo-Y ofDrosophila miranda: I. Comparison at the DNA sequence level (1996)
    Springer
    Journal of molecular evolution 43 (1996), S. 405-412 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Lcp gene family ; Gene homogenization ; CAAT-box motifs ; Gene phylogeny ; Sex chromosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The larval cuticle protein genes (Lcps) represent a multigene family located at the right arm of the metacentric autosome 2 (2R) inDrosophila melanogaster. Due to a chromosome fusion theLcp locus ofDrosophila miranda is situated on a pair of secondary sex chromosomes, theX2 andneo-Y chromosome. Comparing the DNA sequences fromD. miranda andD. melanogaster organization and the gene arrangement ofLcp1-Lcp4 are similar, although the intergene distances vary considerably. The greatest difference betweenLcp1 andLcp2 is due to the occurrence of a pseudogene inD. melanogaster which is not present inD. miranda. Thus the cluster of the fourLcp genes existed already before the separation of themelanogaster andobscura group. Intraspecific homogenizations of different cluster units must have occurred repeatedly between theLcp1/Lcp2 andLcp3/Lcp4 sequence types. The most obvious example is exon 2 of theLcp3 gene inD. miranda, which has been substituted by the corresponding section of theLcp4 gene rather recently. The homogenization must have occurred before the translocation which generated theneo-Y chromosome.Lcp3 ofD. melanogaster has therefore no orthologous partner inD. miranda. Rearrangements in the promoter regions of theD. miranda Lcp genes have generated new, potentially functional CAAT-box motifs. Since three of theLcp alleles on theneo-Y are not expressed andLcp3 is expressed only at a reduced level, it is suggestive to speculate that the rearrangements might be involved ascis-regulatory elements in the up-regulation of theX2-chromosomalLcp alleles, inDrosophila an essential process for dosage compensation. TheLcp genes on theneo-Y chromosome have accumulated more base substitutions than the corresponding alleles on theX2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02339014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Evolution of the larval cuticle proteins coded by the secondary sex chromosome pair:X2 andneo-Y ofDrosophila miranda: II. Comparison at the amino acid sequence level (1996)
    Springer
    Journal of molecular evolution 43 (1996), S. 413-417 
    Details
    ISSN: 1432-1432
    Keywords: Drosophila ; Cuticle proteins (LCP) ; Conserved protein motifs ; Gene phylogeny ; Sex chromosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The larval cuticle proteins (LCPs) are encoded by a multigene family,Lcp1-4, located at the right arm of the metacentric autosome 2 (2R) inDrosophila melanogaster. Due to a chromosome fusion theLcp locus ofDrosophila miranda is situated on a pair of secondary sex chromosomes, theX2 andneo-Y chromosomes. Comparing the deduced amino acid sequences of the autosomalD. melanogaster loci with the sex-chromosomal loci ofD. miranda, we were able to trace the evolution of theLcp loci with respect to their different chromosomal inheritance. The length of the signal peptide is conserved in all four LCPs, while the size of the mature LCPs varies. Conserved protein motifs became obvious from the alignment, indicating regions of structural and functional importance. Analyzing intra- and interspecific sequence similarities of theLcp gene families allowed us to reconstruct the phylogeny of the gene cluster. Alignment with cuticle amino acid sequences originating from divergent insect species reveals motifs already present in the primordial insect LCPs. These motifs indicate different levels of constraint acting during the evolution of the LCPs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02339015
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Interactions between the regulatory regions of twoAdh alleles (1996)
    Springer
    Genetica 97 (1996), S. 1-14 
    Details
    ISSN: 1573-6857
    Keywords: alcohol dehydrogenase ; Drosophila ; enhancer ; regulation ; transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A region (NS1) that acts like an enhancer is located approximately 300 bp upstream of the larval cap site in theAdh gene ofD. melanogaster. When this sequence is deleted (ΔNS1), the gene fails to express ADH protein. Gene expression can be restored by placing a secondAdh gene with an intact enhancer elsewhere on the same plasmid. In these circumstances, both genes are expressed equally regardless of their orientation on the plasmid. In this report we further characterize the interactions that occur when a single enhancer activates expression from a proximal and distant promoter. We have made the following observations: (1) While the two genes are expressed equivalently, their expression relative to a plasmid carrying two intact genes is reduced by a factor of 2 to 6 depending on the orientation of the two genes. (2) The single enhancer drives expression of both genes on any given plasmid molecule. (3) The enhancer does not interact with theAdh gene from which the NS7 region (which spans the larval TATA box) is removed. (4) Expression of the ΔNS1 gene can be restored by an intact gene when both are inserted together into theDrosophila genome via P element-mediated transformation. (5) Increasing the separation between the two genes on a plasmid by up to 15 kbp does not prevent the restoration of expression of the ΔNS1 gene. We propose a model that explains how a single enhancer can stimulate equal expression from two genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00132575
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Different photoreceptors within the same retina express unique combinations of potassium channels (1996)
    Springer
    Journal of comparative physiology 178 (1996), S. 513-522 
    Details
    ISSN: 1432-1351
    Keywords: Potassium channel ; Photoreceptor ; Calliphora ; Drosophila ; Shaker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Single electrode current and voltage clamp recordings in Calliphora, and whole-cell voltage clamp recordings in Drosophila were used to characterise the voltage-gated K channels in both major classes of photoreceptors, R7/8 (long visual fibres, LVFs) and R1-6 (short visual fibres, SVFs). R7/8 were identified by their unique spectral properties, ca. 3–4 fold higher input resistances and 3–4 fold lower cell capacitance. In Calliphora SVFs possess both fast and slow activating delayed rectifier potassium conductances. Drosophila SVFs possess a slowly inactivating delayed rectifier (IKs), a very rapidly inactivating A channel encoded by the Shaker gene (IA), and, in a minority of cells, a third K conductance with intermediate kinetics (IKf). In both specs the LVFs lack the slowest component, but exhibit the faster K conductance(s) with properties indistinguishable from those in the SVFs. These findings add to established evidence demonstrating the significant role played by potassium channels in tuning the photoreceptor membrane. The results also suggest that R1-6 photoreceptors and R7/8 form inputs to visual subsystems tuned to different temporal frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190181
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    vestigial gene expression in Drosophila melanogaster is modulated by the dTMP pool (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 91-98 
    Details
    ISSN: 1617-4623
    Keywords: Key words vestigial ; Drosophila ; Antifolates ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The vestigial (vg) gene of Drosophila melano-gaster encodes a nuclear protein which plays a key role in wing formation but is also involved in other developmental processes. We have previously shown that depletion of the dTMP pool by aminopterin, an inhibitor of the enzyme dihydrofolate reductase, or by fluorodeoxyuridine, an inhibitor of thymidylate synthetase, induces nicks in the wings of wild-type flies and a strong vg phenotype in vg BG /+ flies and also in individuals heterozygous for a deficiency of the vg locus (vg B /+). Furthermore, specific alterations of the vg locus, caused by intronic insertions, are associated with resistance to these drugs. In this paper, we show that: (1) depletion of the dTMP pool by aminopterin leads to a decrease in the amount of vg transcripts; (2) insertion of the retrotransposon 412 in the vg BG mutant, which is resistant to aminopterin, leads to the formation of a truncated transcript that is prematurely terminated in the long terminal repeat of this transposable element; and (3) aminopterin also affects the level of this truncated transcript. These results indicate that alterations of the wing by inhibitors of dTMP synthesis are caused by an effect of these drugs on levels of vg transcripts; the resistance to such agents observed for the vg BG strain is not due to a qualitatively different effect of this drug on the vg transcript but, rather, is related to the expression of a modified Vg protein encoded by a truncated transcript. These results are compatible with a role for vestigial in modulating cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174349
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Vestigial gene expression inDrosophila melanogaster is modulated by the dTMP pool (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 91-98 
    Details
    ISSN: 1617-4623
    Keywords: vestigial ; Drosophila ; Antifolates ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thevestigial (vg) gene ofDrosophila melanogaster encodes a nuclear protein which plays a key role in wing formation but is also involved in other developmental processes. We have previously shown that depletion of the dTMP pool by aminopterin, an inhibitor of the enzyme dihydrofolate reductase, or by fluorodeoxyuridine, an inhibitor of thymidylate synthetase, induces nicks in the wings of wild-type flies and a strongvg phenotype invg BG /+ flies and also in individuals heterozygous for a deficiency of thevg locus (vg B /+). Furthermore, specific alterations of thevg locus, caused by intronic insertions, are associated with resistance to these drugs. In this paper, we show that: (1) depletion of the dTMP pool by aminopterin leads to a decrease in the amount ofvg transcripts; (2) insertion of the retrotransposon412 in thevg BG mutant, which is resistant to aminopterin, leads to the formation of a truncated transcript that is prematurely terminated in the long terminal repeat of this transposable element; and (3) aminopterin also affects the level of this truncated transcript. These results indicate that alterations of the wing by inhibitors of dTMP synthesis are caused by an effect of these drugs on levels ofvg transcripts; the resistance to such agents observed for thevg BG strain is not due to a qualitatively different effect of this drug on thevg transcript but, rather, is related to the expression of a modified Vg protein encoded by a truncated transcript. These results are compatible with a role forvestigial in modulating cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174349
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Interactions betweencut wing mutations and mutations inzeste, and theenhancer of yellow andPolycomb group genes ofDrosophila melanogaster (1996)
    Springer
    Molecular genetics and genomics 252 (1996), S. 230-236 
    Details
    ISSN: 1617-4623
    Keywords: Drosophila ; cut ; zeste ; Polycomb ; su(Hw)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phenotypic expression of several mutations in thecut locus ofDrosophila melanogaster is modified by mutations in thezeste, e(y)2 ande(y)3 genes and in some genes of thePolycomb group. All tested sensitivecut mutations have a partially inactivated cut wing enhancer.e(y)3 ul, zv77h andSu(z)2 5 mutations enhance, whilee(y)2 ul, zOp6, Psc1, Su(z)301, Su(z)302 andScm D1 mutations suppress the ct mutant phenotype. The results are discussed in terms of the role of long-distance interactions and DNA compaction in transcriptional control of thecut locus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02173768
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Interactions among the bHLH domains of the proteins encoded by theEnhancer of split andachaete-scute gene complexes ofDrosophila (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 628-634 
    Details
    ISSN: 1617-4623
    Keywords: Drosophila ; Enhancer of split ; achaete-scute ; Helix-loop-helix proteins ; Protein-protein interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract TheEnhancer of split andachaete-scute gene complexes [E(spl)-C and AS-C] encode helix-loop-helix proteins required for neurogenesis inDrosophila. Using a heterologous bacterial system, we show that (i) the bHLH domains of the proteins encoded by the two gene complexes differ in their ability to form homo- and/or heterodimers; (ii) the bHLH domains of the E(spl)-C proteins m5, m7 and m8 interact with the bHLH domains of the Ac and Sc proteins. These bHLH domains form an interaction network which may represent the molecular mechanism whereby the competent state of the proneural cells is maintained until the terminal determination to neuroblast occurs. Also, the pattern of interactions of the bHLH domains of certain proteins encoded by the two gene complexes may explain their functional redundancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174111
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Effect of thermal environment on life histories of free living Drosophila melanogaster and D. subobscura (1996)
    Springer
    Oecologia 108 (1996), S. 262-272 
    Details
    ISSN: 1432-1939
    Keywords: Drosophila ; Temperature performance ; Life history ; Thermal environment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The variability of morphological and lifehistory traits in Drosophila melanogaster and D. subobscura, two sympatric Drosophila species of different climatic origin, were investigated with regard to seasonal and daily temperature and humidity fluctuations to assess thermal sensitivity and the responses of freeliving organisms to oscillating temperatures. Temperature and humidity were measured continuously at the site where Drosophila were observed throughout the day, and thus represent a realistic picture of the temperature environment of these animals. A phenotypic model (gaussian curve) of temperature performance was fitted to daily fecundities and provided estimates of the position of temperature optimum and of the maximum and the breadth of performance for both species. D. melanogaster had a higher optimum temperature than D. subobscura. A trade-off between the maximum and the breadth of performance was detected both within and between the species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334650
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Nested subset structure of larval mycophagous fly assemblages: nestedness in a non-island system (1996)
    Springer
    Oecologia 107 (1996), S. 257-264 
    Details
    ISSN: 1432-1939
    Keywords: Nested subsets ; Drosophila ; Community structure ; Species-area relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nested subset structure has been studied in archipelagoes and fragmented habitats, and has been attributed to differential colonization and extinction rates among species and nested environmental tolerances. In this experiment, we tested for nestedness in assemblages of mycophagous fly larvae. Twenty mushrooms in each of three size classes (4.8–6.0 g, 10–15 g, 21–32 g) were placed on moist potting soil in experimental cups. The cups were placed in oak and pine forests in Greenville, S.C., USA for 5 days, where they were available to ovipositing flies. Upon collection, the mushrooms were incubated in the laboratory for 3 weeks and all emerging flies were sorted by species, counted, and weighed. A random placement analysis was conducted to determine whether the species richness pattern was a sampling artifact of the species abundance distributions. The actual species richness pattern did not conform to the random placement model; most mushrooms contained significantly fewer species than predicted by random sampling. The communities were strongly nested as measured by two different indices, and the nestedness pattern was related to mushroom size. Small mushrooms usually produced no flies or a single species, Dohrniphora sp. (Phoridae). Medium and large mushrooms typically produced more species-rich communities that usually contained the phorid and Drosophila putrida, D. tripunctata, and Leucophenga varia. This core guild was nested within a more diverse assemblage that included D. falleni, Mycodrosophila dimidiata, a muscid, and two Leptocera sp. (sphaeroceridae). These patterns are tentatively explained in the context of nested desiccation tolerances, mediated by differences in mushroom size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327910
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Genetics and the environment in interspecific competition: a study using the sibling species Drosophila melanogaster and Drosophila simulans (1996)
    Springer
    Oecologia 108 (1996), S. 72-78 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Environment ; Fitness ; Genetic variation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The outcome of interspecific competition of two closely related species may depend upon genetic variation in the two species and the environment in which the experiment is carried out. Interspecific competition in the two sibling species, Drosophila melanogaster and D. simulans, is usually investigated using longterm laboratory stocks that often have mutant markers that distinguish them. To examine competition in flies that genetically more closely resemble flies in nature, we utilized freshly caught wildtype isofemale lines of the two species collected at the same site in San Carlos, Mexico. Under ordinary laboratory conditions, D. melanogaster always won in competition. However, in hotter and drier conditions, D. simulans competed much more effectively. In these environmental conditions, there were genetic differences in competitive ability among lines with the outcome of competition primarily dependent upon the line of D. melanogaster used but in some cases also influenced by the line of D. simulans used. Differences in the measures of productivity and developmental time did not explain the differences in competitive ability among lines. This suggests that the outcome of competition was not due to differences in major fitness components among the isofemale lines but to some other attribute(s) that influenced competitive ability. When lines of flies were combined, the outcome of competition was generally consistent with competitive outcomes between pairs of lines. In several cases, the combination of lines performed better than the best of the constituent lines, suggesting that competitive ability was combined heterotically and that the total amount of genetic variation was important in the outcome of interspecific competition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333216
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    The colonization of organges by the cosmopolitan Drosophila (1996)
    Springer
    Oecologia 108 (1996), S. 552-561 
    Details
    ISSN: 1432-1939
    Keywords: Drosophila ; Colonization ; Ecology ; Succession ; Guild
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The guild of “cosmopolitan” Drosophila coexist almost worldwide and yet the mechanisms that underlie this coexistence are unknown. The larval resource of the guild is decaying fruit and vegetables, but the species show little specialization and can coexist on a single resource, such as oranges. In southern California the guild includes D. simulans (SIM), D. melanogaster (MEL), D. pseudoobscura (OBS), D. immigrans (IMM), D. hydei (HYD) and D. busckii (BUS). These species show consistent differences in their colonization of decaying organges, differences that may promote their coexistence. This study tested whether the colonization pattern of a species is determined primarily by attraction to specific resource types (decayed or fresh organges), by ability to colonize new resource patches, or by dependence on a successional sequence of Drosophila species. The experiments compared oranges that were pre-aged prior to a colonization period and showed that the colonization pattern of each species (except OBS) was driven primarily by its decay-dependent attraction to oranges. While OBS exhibited a pattern of colonization independent of pre-aging, the remaining species all showed some preference for older (7-day pre-aged) over fresh oranges. Their overall pattern of attraction, ordered by high relative abundance on fresher organges, was SIM〉MEL=IMM〉HYD=BUS. BUS, a specialist on decaying plant material, was the only species that showed a preference for 11-day over 7-day oranges. Pre-aging the oranges under covers, to prevent prior colonization by Drosophila, did not change the interspecific pattern of colonization, indicating that microbial decay was driving the changes in attraction. The patterns of attraction separated two ecologically similar pairs (SIM from MEL; IMM from HYD) and published data on ethanol tolerance show that, in each pair, the earliest colonizer has the lower tolerance. This suggests an important interplay between colonization patterns and physiological optima.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333733
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    The accessory gland proteins in maleDrosophila: structural, reproductive, and evolutionary aspects (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 503-510 
    Details
    ISSN: 1420-9071
    Keywords: Drosophila ; accessory gland ; reproduction ; sexual behavior ; sperm displacement ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Recent results from biochemical and molecular genetic studies of the accessory gland proteins in maleDrosophila are reviewed. The most prominent feature is the species-specific variability. However, the analysis of the sex peptide inD. melanogaster shows that there is a strong homology in the molecular structure to the closely related sibling species, and that divergence increases with increasing phylogenetic distance. For this reason the sex peptide, after being transferred to the female genital tract during copulation, reduces receptivity and increases oviposition only in virgin females belonging to the same species group and subgroup. Even though studies were hitherto limited to a small number of the secretory components, it is evident that the accessory gland proteins play a key role in reproductive success of the fruit fly by changing female sexual behavior, supporting sperm transfer, storage and displacement. Thus, genes encoding the accessory gland proteins are apparently under strong evolutionary selection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01969718
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Rapid development and a long life: an association expected under a stress theory of aging (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 643-646 
    Details
    ISSN: 1420-9071
    Keywords: Aging ; development time ; stress ; energy cost ; oxidative stress ; Drosophila ; homeostasis ; life span
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Life span and development time are considered in the context of the abiotic stresses to which free-living organisms are normally exposed. Under these circumstances, long life span depends upon metabolically efficient stress-resistance genes, which tend to be heterozygous. Similarly, rapid development time tends to be a feature of heterozygous stress-resistant individuals. Therefore, individuals who have high inherited stress resistance should develop fastest and live longest; in addition, they should show high homeostasis in the face of the energy costs of stress. In this way, the stress theory of aging can incorporate the developmental stage, based upon oxidative stress as an important major direct challenge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01925565
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Synthesis of a ubiquitously present new HSP60 family protein is enhanced by heat shock only in the Malpighian tubules ofDrosophila (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 751-756 
    Details
    ISSN: 1420-9071
    Keywords: Chaperonin ; Drosophila ; groEL ; heat shock ; heat shock proteins ; HSP60 ; Malpighian tubules ; TCP-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A homologue of the chaperonin protein of the HSP60 family has not been shown so far inDrosophila. Using an antibody specific to HSP60 family protein in Western blotting and immunocytochemistry, we showed that a 64-kDa polypeptide, homologous to the HSP60, is constitutively present in all tissues ofDrosophila melanogaster throughout the life cycle from the freshly laid egg to all embryonic, larval and adult stages. A 64-kDa polypeptide reacting with the same antibody in Western blots is present in all species ofDrosophila examined. Using Western blotting in conjunction with35S-methionine labeling of newly synthesized proteins and immuno-precipitation of the labeled proteins with HSP60-specific antibody, it was shown that synthesis of the 64-kDa homologue of HSP60 is appreciably increased by heat shock only in the Malpighian tubules, which are already known to lack the common HSPs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01923984
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Size-related sexual selection and yeast diet inDrosophila buzzatii (Diptera: Drosophilidae) (1996)
    Springer
    Journal of insect behavior 9 (1996), S. 329-338 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; size-related sexual selection ; yeast diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Size-related sexual selection (SRSS) was examined on four traits (thorax and wing length and head and face width) inDrosophila buzzatii, by scoring male copulatory status in two mass-mating experiments. Using axenic females, experiment 1 was carried out with axenic males, and experiment 2 with yeast-supplemented males. While there was no indication of SRSS in experiment 1, such selection was substantial in yeast-supplemented males, which transmitted yeasts to mating females. Multivariate analyses of selection indicated that face width is the measured trait on which directional SRSS essentially acted in yeast-supplemented males, resulting in indirect selection on body size. Because this selection was affected by yeast diet in males, its possible interaction with the yeast transmission from males to females during the courtship is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02213875
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Female wing spreading as acceptance signal in theDrosophila virilis group of species (1996)
    Springer
    Journal of insect behavior 9 (1996), S. 505-516 
    Details
    ISSN: 1572-8889
    Keywords: courtship ; female behavior ; signals ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females of manyDrosophila species spread apart their wings prior to copulation. In the present study we found female wing spreading to provoke male copulation attempts inDrosophila virilis-group species, helping the males to attempt copulation when the female is ready to mate. The males of most species, however, rarely responded to female wing spreading by copulation attempt without licking the female genitalia before and/or after female wing spreading bout. Blocking the female genitalia (D. virilis, D. novamexicana) reduces males' tendency to attempt copulation after female wing spreading. In these, and most other species of the group, female wing spreading seems to be an efficient signal only when combined with stimuli from female genitalia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02214026
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Natural selection in the laboratory for a change in resistance byDrosophila melanogaster to the parasitoid waspAsobara tabida (1996)
    Springer
    Journal of insect behavior 9 (1996), S. 477-491 
    Details
    ISSN: 1572-8889
    Keywords: Drosophila ; behavior ; polymorphism ; parasitoid wasp ; host defense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The selection response of the polymorphic hostD. melanogaster (Meigen) to the braconid waspA. tabida (Nees) is addressed. Cages of flies with and without wasps were initiated with a population ofD. melanogaster that exhibited variation both in larval foraging behavior and in encapsulation ability. Encapsulation ability was measured as the proportion of parasitized larvae that produce a hardened capsule which encapsulates the wasp egg and ultimately kills the wasp larva. We determined whether the host population changed its encapsulation ability and/or its foraging behavior in response to the wasp. Both species were collected from a local orchard whereA. tabida is the only wasp known to parasitizeD. melanogaster larvae. The naturally occurring genetic polymorphism for rover and sitter larval foraging behavior inD. melanogaster is also found in this field population.A. tabida's vibrotactic search behavior enables it to detect rover more frequently than sitter larvae. Rover larvae move significantly more while feeding than do sitter larvae. In this field population, rover larvae also show higher encapsulation abilities than do sitter larvae. Six cage populations, three without wasps and three with wasps, each containing an equal mixture of rover and sitter flies, were established in the laboratory and maintained for 19 fly generations. Selection pressure in the laboratory was similar to that found in the field population from which the flies and wasps were derived. We found that larvae from cages with wasps developed a significantly higher frequency of encapsulation than those reared without wasps. We were, however, unable to detect a change in larval movement (rover or sitter behavior) in larvae from cages subject to selection from wasps compared to larvae from cages containing no wasps. This may have resulted from a balance between two selective forces, selection against rovers by the wasps' use of vibrotaxis, and selection for rovers resulting from their increased encapsulation abilities
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02214024
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    The role of gap junction membrane channels in development (1996)
    Springer
    Journal of bioenergetics and biomembranes 28 (1996), S. 379-385 
    Details
    ISSN: 1573-6881
    Keywords: Development ; gap junctions ; mouse embryos ; Drosophila ; connexin 43 ; transgenic mouse ; neural tube defects ; neural crest cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract In most developmental systems, gap junction-mediated cell-cell communication (GJC) can be detected from very early stages of embryogenesis. This usually results in the entire embryo becoming linked as a syncytium. However, as development progresses, GJC becomes restricted at discrete boundaries, leading to the subdivision of the embryo into communication compartment domains. Analysis of gap junction gene expression suggests that this functional subdivision of GJC may be mediated by the differential expression of the connexin gene family. The temporal-spatial pattern of connexin gene expression during mouse embryogenesis is highly suggestive of a role for gap junctions in inductive interactions, being regionally restricted in distinct developmentally significant domains. Using reverse genetic approaches to manipulate connexin gene function, direct evidence has been obtained for the connexin 43 (Cx43) gap junction gene playing a role in mammalian development. The challenges in the future are the identification of the target cell populations and the cell signaling processes in which Cx43-mediated cell-cell interactions are critically required in mammalian development. Our preliminary observations suggest that neural crest cells may be one such cell population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02110114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Evolution of dosage compensation (1996)
    Springer
    Chromosome research 4 (1996), S. 185-190 
    Details
    ISSN: 1573-6849
    Keywords: sex chromosome evolution ; dosage compensation ; Drosophila ; histone acetylation ; X chromosome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In polytene chromosome squashes from the fruit flyDrosophila melanogaster, the single, dosage-compensated X chromosome in males can be distinguished from the autosomes by the presence of an isoform of histone H4 acetylated at lysine 16, H4.Ac16. We have used H4.Ac16 as a marker to examine the evolving relationship between dosage compensation and sex chromosome composition in species ofDrosophila with one (D. melanogaster), two (D. pseudoobscura) or three (D. miranda) identifiable X chromosome arms. In each case, we find that H4.Ac16 is distributed as discrete, closely spaced bands along the entire length of each X chromosome, the only exception being the X2 chromosome ofD. miranda in which a terminal region constituting about 10% of the chromosome by length is not labelled with anti-H4.Ac16 antibodies. We conclude that, with this exception, dosage compensation extends along the X chromosomes of all three species. AsD. pseudoobscura andD. miranda diverged only about 2 Mya, the spread of dosage-compensated loci along X2 has been rapid, suggesting that regional changes rather than piecemeal, gene-by-gene, changes may have been involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02254957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Reduced transmitter release conferred by mutations in theslowpoke-encoded Ca2+-activated K+ channel gene ofDrosophila (1996)
    Springer
    Invertebrate neuroscience 2 (1996), S. 51-60 
    Details
    ISSN: 1439-1104
    Keywords: slowpoke ; potassium channels ; synaptic transmission ; Drosophila ; excitable membranes ; genetic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Potassium channels control the repolarization of nerve terminals and thus play important roles in the control of synaptic transmission. Here we describe the effects of mutations in theslowpoke gene, which is the structural gene for a calcium activated potassium channel, on transmitter release at the neuromuscular junction inDrosophila melanogaster. Surprisingly, we find that theslowpoke mutant exhibits reduced transmitter release compared to normal. Similarly, theslowpoke mutation significantly suppresses the increased transmitter release conferred either by a mutation inShaker or by application of 4-aminopyridine, which blocks theShaker-encoded potassium channel at theDrosophila nerve terminal. Furthermore, theslowpoke mutation suppresses the striking increase in transmitter release that occurs following application of 4-aminopyridine to theether a go-go mutant. This suppression is most likely the result of a reduction of Ca2+ influx into the nerve terminal in theslowpoke mutant. We hypothesize that the effects of theslowpoke mutation are indirect, perhaps resulting from increased Ca2+ channel inactivation, decreased Na+ or Ca2+ channel localization or gene expression, or by increases in the expression or activity of potassium channels distinct fromslowpoke.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02336660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Developmental isolation and subsequent adult behavior ofDrosophila paulistorum. II. Prior experience (1996)
    Springer
    Behavior genetics 26 (1996), S. 15-25 
    Details
    ISSN: 1573-3297
    Keywords: Mating behavior ; reproductive isolation ; sexual isolation ; semispecies ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Preadult seclusion imposed upon members of theDrosophila paulistorum complex of intersterile semispecies significantly decreased sexual isolation between adults of the semispecies. While seclusion at any developmental stage had this effect, there were quantitative variations correlated with the stage at which seclusion had been initiated: the earlier the stage at which seclusion began, the more frequent were the heterogamic matings. All the stages of development seemed to contribute to final adult sexual behavior, with no single stage emerging as the most important experiential phase. Seclusion also significantly affected intrasemispecific matings, in that flies were more likely to mate with partners having similar experiences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02361155
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Developmental isolation and subsequent adult behavior ofDrosophila paulistorum. III. Alternative rearing (1996)
    Springer
    Behavior genetics 26 (1996), S. 27-37 
    Details
    ISSN: 1573-3297
    Keywords: Mating behavior ; reproductive isolation ; sexual isolation ; semispecies ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract We have been utilizing membres of theDrosophila paulistorum complex of semispecies to study the development of adult discriminatory behavior. In this study, three rearing methods were used to examine the effects of previous exposure to heterosemispecifics on reproductive isolation among the various semispecies. Experimental flies were exposed to heterosemispecifics by one of three methods: exposure to airborne heterosemispecific stimuli from egg through sexual maturity, physical contact with heterosemispecifics only during the postimaginal period, and mixed culturing (total physical contact with heterosemispecific individuals during each of five preimaginal stages). Effects of the first treatment varied with semispecies. The second treatment had no significant effect on mating behavior. The third treatment of mixed culturing reinforced sexual isolation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02361156
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...