Gustatory stimuli, such as sugar, induce a behavioral response in Drosophila that involves extension of the proboscis and consumption of the sugar-containing solution. Addition of salt to the sugar ...solution inhibits this behavioral response. However, the mechanisms and gene products involved in the salt aversion response have not been described. Here, we report the identification of a locus, defective proboscis extension response (dpr), that is required for salt aversion. dpr was expressed in a subset of primary neurons in the gustatory organs and encoded a protein with two Ig-like domains, a single putative transmembrane domain, and a short region C terminal to the transmembrane segment. In addition, DPR defines a large previously unknown group of > or =20 highly related Ig-containing proteins.
Using an antibody against bromodeoxyuridine we have analyzed the distribution of S-phase nuclei in the wing disc of Drosophila as the larval disc transforms into the adult wing during metamorphosis. ...On the basis of the timing of replication three cell populations can be distinguished: the cells of the presumptive wing margin, the precursor cells of the longitudinal veins, and those of the intervein regions. In each of these populations the cell cycle is first arrested and later resumes at a specific time, so that at each developmental time point a characteristic spatial pattern of S-phase nuclei is seen. An interpretation of these changing patterns in terms of vein formation, compartments, and neural development is offered.
The current paper builds on Reports #34 and 35 in this series, which discussed the use of collaborative software to develop online communities in distance education (DE). The paper illustrates the ...manner in which an educational community's needs should be carefully examined, in the process of designing techniques that fulfill these needs at a distance. Student perceptions of their theological education community at Concordia Seminary, St. Louis, Missouri (http://www.csl.edu/Home.html) are investigated, via a survey instrument designed to define the students' communal needs.
A detailed mapping and description of campaniform sensilla on the wing and haltere of Drosophila melanogaster is provided. Six types of sensilla are distinguished. Similarities in the pattern of ...their distribution on the dorsal and ventral surfaces of each appendage, as well as between the wing and haltere, are apparent. These data are used to assess the quality of homeotic transformation in several mutants of the bithorax complex in which the halteres are transformed into wings. Flies homozygous for abxbx3pbx produce a complete inventory of wing sensilla on the homeotic appendage. In abx, bx3 and bx3pbx homozygotes the transformation of haltere into wing is incomplete, and each mutant shows characteristic fields of haltere and wing sensilla. It appears that specific regions of the anterior haltere compartment require different combinations of mutant alleles to produce a distinct homeotic transformation. Furthermore, the pbx mutation appears to influence expression of the bx3 mutation within the anterior compartment.
This paper focuses on research that was carried out to identify learning needs and resources within Christian congregations that are aligned with Critical Behaviors, Success Indicators, and Strategic ...Mission Outcomes. Within a congregation, the alignment of learning resources with desired mission and ministry outcomes is a critical step in raising a congregation's capacity to achieve its desired Mission Outcomes. Through the use of an instrument called an Impact Map it was possible to identify strategic learning needs, within a sample of ten congregations, which are directly aligned with congregational goals. The research shows that the top learning need category for congregational members pertains to the development of interpersonal relationships and the sense of community in the congregation. While the top learning need category for congregational leaders pertains to the development of new leadership. The research suggests that there is a relationship between congregational size and the availability of learning resources that are aligned with Strategic Mission Outcomes. Compared to large congregations, small congregations have fewer well aligned learning resources.
The current paper builds on Reports #34 and 35 in this series, which discussed the use of collaborative software to develop online communities in distance education (DE). The paper illustrates the ...manner in which an educational community's needs should be carefully examined, in the process of designing techniques that fulfill these needs at a distance. Student perceptions of their theological education community at Concordia Seminary, St. Louis, Missouri (http://www.csl.edu/Home.html) are investigated, via a survey instrument designed to define the students' communal needs.
A bang-sensitive enhancer trap line was isolated in a behavioral screen. The flies show a weak bang-sensitive paralysis, recovering after about 7 s. The P element insert is localized at 93B1-2 on the ...salivary chromosomes, the site of the (Na+,K+)ATPase alpha subunit gene. Molecular characterization demonstrates that the transposon is inserted into the first intron of this gene. This insertion leads to normal-sized transcripts, but reduced levels of expression. This change is also reflected in lower amounts of a normal-sized alpha subunit protein. Mutant flies show a much greater sensitivity to ouabain, likewise indicating, on a functional level, a reduction in Na+ pump activity. Furthermore, the bang-sensitive behavior can also be mimicked by injecting sublethal doses of ouabain into wild-type flies. The molecular and functional evidence indicates that the insertion has produced a hypomorphic mutation of the (Na+,K+)ATPase alpha subunit gene, opening the way to future studies of the regulation of the Na+ pump.
A new monoclonal antibody, specific to an epitope in the carboxyl terminus of the Drosophila collagen IV molecule (basement membrane collagen) was identified. The distributions of collagen IV, ...laminin, and an additional extracellular molecule, the 2G2 antigen (2G2-Ag), were followed immunocytochemically during early wing development. In late third instar larvae, collagen IV and laminin surround the entire wing disc, whereas the 2G2-Ag is limited to the region of the future wing pouch. For the first few hours following eversion of the disc, all three ECM components line the basal surfaces of all epithelial cells in the wing pouch, both those destined to line the wing veins and those destined to become tightly apposed in the large intervein regions. Collagen IV and laminin persist on these cells during the two initial rounds of apposition of dorsal and ventral wing surfaces; later, they become restricted to the cells lining the veins. The 2G2-Ag disappears completely quite early in the pupal period. Collagen IV appears to be synthesized at least twice, once in the larva and a second time in the pupa; in between it is enzymatically cleaved and may be eliminated, probably by hemocytes. In an extreme allele of blistered the wing is ballooned to form a single internal space. Collagen IV and laminin line all basal wing cell surfaces early in pupal development as they do in the wild type. Later, however, they continue to line the entire cavity of the mutant wing rather than assuming a restricted distribution. In a completely veinless wing (rhomboidveinlet vein), collagen IV and laminin are also present generally on basal surfaces at early times, but are completely absent between the tightly apposed wing layers later. The ECM distributions both in wild type wings and in mutants suggest that the matrix plays a role in the establishment of the wing variation pattern. One possibility, strengthened by recent findings regarding ECM receptors in Drosophila, is their involvement in dorsal-ventral wing layer adhesion. Our findings also lead us to suggest that certain sets of features which distinguish vein from intervein cells may be linked during cell differentiation and thus help to define these cell phenotypes. The features include cytoskeletal specializations and certain cell surface and ECM molecules.
The current paper builds on Reports #34 and 35 in this series, which discussed the use of collaborative software to develop online communities in distance education (DE). The paper illustrates the ...manner in which an educational community's needs should be carefully examined, in the process of designing techniques that fulfill these needs at a distance. Student perceptions of their theological education community at Concordia Seminary, St. Louis, Missouri (http://www.csl.edu/Home.html) are investigated, via a survey instrument designed to define the students' communal needs.
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