Differentiation capacities of the dorsal metathoracic (haltere) disc ofDrosophila melanogaster

Summary The mature haltere disc, when implanted into a larva of the same age, undergoes metamorphosis along with the host, and produces a haltere, haltere sclerite, notum III, and pleural process. Implants ordinarily form an inverted vesicle, into which the haltere is frequently everted, usually only partly. Many adventitious bristles may be formed which are not foundin situ. It was found thatsc may reduce, andmwh may increase the number of sensilla.On the basis of results obtained from transplanted disc fragments an organ map of the haltere disc was constructed, which shows the presumptive haltere area to be located in the posterio-central part of the disc, while the anterio-medial part forms the thoracic structures dorsal to the haltere, and the posterio-lateral part the thoracic structures ventral to it. The anlage of the adventitious bristles is probably within the notum area. The haltere anlage proper is concentric; the prospective distal capitellum is located in the center, and is surrounded by the anlagen of the more proximal segments.The organ map of the haltere disc is compared with that of other discs. Organ maps seem to be basically concentric. There is a close homology between the maps of the wing and the haltere disc.     

Operations on the pupal wing ofDrosophila melanogaster

Journal of Genetics -     

A cinematographic study of the embryology ofDrosophila melanogaster

Summary In connection with studies on the effect of genetic abnormalities on development, a film was made of the normal development of theDrosophila embryo. Time-lapse motion technique was used, and this made it possible to make new observations on those phases of the development which involve large re-arrangements of the embryonic material, in particular on blastoderm formation, gastrulation and involution of the head. These new observations have been incorporated in an account of the complete development of the embryo up to the time of hatching.     

Characterization of prostanoid receptors present on adrenergic neurons innervating the porcine uterine longitudinal muscle

The cyclooxygenase-prostanoid pathway regulates myometrial contractility through activation of prostanoid receptors on uterine smooth muscles. However, the possible expression of prostanoid receptors on autonomic nerves cannot be excluded completely. The aim of the present study was to clarify the presence of neural prostanoid receptors on adrenergic nerves in the porcine uterine longitudinal muscle. In [(3)H]-noradrenaline-loaded longitudinal muscle strips of porcine uterus, electrical field stimulation (EFS) evoked [(3)H]-noradrenaline release in a stimulation frequency-dependent manner. The EFS-evoked release was completely abolished in Ca(2+)-free (EGTA, 1mM) incubation medium and by tetrodotoxin or omega-conotoxin GVIA, suggesting that [(3)H]-noradrenaline was released from neural components. The EFS-evoked [(3)H]-noradrenaline release was significantly enhanced by treatment with indomethacin. In the presence of indomethacin, PGE(2) and PGF(2alpha), but not PGD(2), inhibited the EFS-evoked [(3)H]-noradrenaline release. Of synthetic prostanoid receptor agonists examined, both U46619 (TP) and sulprostone (EP(1)/EP(3)) decreased the EFS-evoked [(3)H]-noradrenaline release in a concentration-dependent manner, while fluprostenol (FP), BW245C (DP) and butaprost (EP(2)) were almost ineffective. SQ29548 (TP receptor antagonist) blocked the effect of U46619, but SC19220 (EP(1) receptor antagonist) did not change the inhibition by sulprostone or PGE(2). Double immunofluorescence staining using protein gene product 9.5, tyrosine hydroxylase, EP(3) receptor and TP receptor antibodies suggested the localization of EP(3) or TP receptors on adrenergic nerves in the porcine uterus. These results indicated that neural EP(3) and TP receptors are present on adrenergic nerves of the porcine uterine longitudinal muscle. Endogenous prostanoid produced by cyclooxygenase can regulate noradrenaline release in an inhibitory manner through activation of these neural prostanoid receptors.     

The ultrastructure of the developing leg ofDrosophila melanogaster

Summary The ultrastructure of the imaginal discs ofDrosophila melanogaster was compared with that of other chitogenous tissues with different developmental capacities, namely, embryonic, larval, pupal and adult epidermis. Attention was paid to features which might be correlated with specific morphogenetic activities. Previous morphological studies of imaginal discs of Diptera were analyzed in detail and a somewhat revised view of imaginal disc structure emerged. The results reveal that the imaginal discs ofD. melanogaster consist of three types of cells: cells of the single layered disc epithelium, adepithelial cells and nerves. Four types of specialized junctions connect the cells of the disc epithelium: zonulae adhaerens, septate desmosomes, gap junctions and cytoplasmic bridges. The junctions are discussed in relation to their possible roles in adhesion and intercellular communication. It was concluded that gap junctions may be a more likely site for the intercellular communication involved in pattern formation than septate desmosomes. Evidence is presented that adepithelial cells are the precursors of imaginal muscles and that some cell lines (atelotypic) are in fact lines of adepithelial cells which can differentiate into muscle.Specific imaginal discs can be easily recognized by their overall morphology, i.e. patterns of folds. However, no ultrastructural features were found which we could correlate with the state of determination of the cells. Most differences in the ultrastructure of different discs at several developmental stages were attributable to different phases of cuticle secretion. The cells of the imaginal disc epithelium are packed with ribosomes but very little rough ER. The amount of rough ER increases rapidly at puparium formation. Cuticulin is recognizable 4–6 hours after puparium formation. Six hours after puparium formation, the cells of the disc epithelium are secreting the epicuticle of the pupa. As the imaginal disc of a leg everts from a folded sac to the tubular pupal leg, the cells of the disc epithelium change from tall columnar to cuboidal. A loss of microtubules in the long axis of the columnar cells accompanies this change. Prepupal morphogenesis of the leg appears to be caused by the change in cell shape. Evidence is presented which is incompatible with previous explanations of the mechanism of eversion of imaginal discs.There is some turnover of the cells of the disc epithelium as evidenced by autophagy and the occasional heterophagy of a dead neighbor. However this does not appear to be an important factor in the morphogenesis of discs. Plant peroxidase which was used as a tracer of proteins in the blood was taken up from the hemolymph by the disc epithelium. Imaginal disc cells contain many lipid droplets which coalesce and are replaced by glycogen during the prepupal period.

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Zusammenfassung Die Feinstrukturen der Imaginalscheiben, der embryonalen, larvalen, pupalen und adulten Epidermis, alles chitinbildende Gewebe, wurden untersucht und miteinander verglichen. Besondere Aufmerksamkeit legten wir auf ultrastrukturelle Merkmale, die mit spezifischen morphogenetischen Vorgängen korreliert sein können. Frühere Untersuchungen über die Morphologie der Imaginalscheiben bei Dipteren wurden kritisch analysiert und führten mit unseren Resultaten zu einem etwas veränderten Bild der Scheibenstruktur. Die Imaginalscheiben vonDrosophila melanogaster bestehen aus drei Zelltypen: Zellen des einschichtigen Epithels, adepitheliale Zellen und Nerven. Die Epithelzellen weisen vier spezialisierte Zellverbindungen auf: zonulae adherens, septate desmosomes, gap junctions und zytoplasmatische Brücken. Die Funktion dieser Zellverbindungen wird im Zusammenhang mit der Zelladhäsion und Zellkommunikation diskutiert. Es scheint, daß während der Musterbildung, die gap junctions, eher als die septate desmosomes, die Orte der Zellkommunikation sind. Wir haben gezeigt, daß adepitheliale Zellen Vorläufer der imaginalen Muskeln sind. Einige atelotypische Linien, die sich als Kulturen adepithelialer Zellen erwiesen, differenzieren Muskeln.Die Imaginalscheiben können leicht an ihrer Gesamtmorphologie, d.h. an ihrem Faltenmuster erkannt werden. Ultrastrukturelle Merkmale wurden jedoch nicht beobachtet, die mit dem Determinationszustand der Zelle korrelierbar wären. Während der Entwicklung sind die meisten Unterschiede in der Feinstruktur auf verschiedene Phasen der Kutikulasekretion zurückzuführen. Die Epithelzellen der Imaginalscheiben zeigen viele Ribosomen, besitzen aber nur sehr wenig endoplasmatisches Reticulum. Dieses nimmt erst bei der Pupariumbildung stark zu. 4–6 Std nach Puparisierung ist Kutikulin nachweisbar und nach 6 Std scheiden die Epithelzellen die Epikutikula aus. Während sich die Beinscheibe vom gefalteten Sack zum röhrenförmigen Bein ausstülpt, werden die länglichen Epithelzellen kubisch. Gleichzeitig mit dieser Formänderung verschwinden die Microtubuli in der Längsachse der Zellen. Die Morphogenese des Beines im Vorpuppenstadium scheint auf eine Änderung der Zellform zu beruhen. Früher beschriebene Erklärungen für den Mechanismus der Ausstülpung sind mit unseren Beobachtungen nicht vereinbar. Autophagozytose und gelegentlich Heterophagozytose einer toten Nachbarzelle konnten in den Epithelzellen nachgewiesen werden. Dies scheint jedoch kein wesentlicher Faktor für die Morphogenese der Scheibe zu sein. Pflanzenperoxydase, als Tracer-Protein im Blut, wird vom Scheibenepithel aus der Hämolymphe aufgenommen. Scheibenzellen enthalten viele Lipidtröpfchen, die sich vereinigen und während des Vorpuppenstadiums durch Glycogen ersetzt werden.

     

Organization of motor neurons innervating the proboscis musculature in Drosophila melanogaster meigen (diptera : Drosophilidae)

The present study addresses the question as to how the motor neurons involved in feeding in Drosophila melanogaster Meigen (Diptera : Drosophilidae) are organized. The motor neurons have been visualized both by Golgi-silver impregnation and by intramuscular injection of horseradish peroxidase, and analyzed in light of the existing information on taste sensory system and the feeding behaviour. The motor neurons have been broadly classified into the following types: labial nerve motor neurons, pharyngeal nerve motor neurons, and accessory pharyngeal nerve motor neurons, depending on the nerve through which their axons exit. The arborization of all the motor neurons is confined to the suboesophageal ganglion (SOG). All of them have predominantly ipsilateral and some contralateral arborizations. Their dendrites predominantly occupy the ventral region of the neuropil of the SOG and partially overlap the taste sensory projections, thereby providing an opportunity for interaction with the taste sensory input. The pharyngeal motor neurons arborize more extensively in the ventral tritocerebram, anteroventral. and mid-ventral neuropil, whereas the dendritic fields of labial motor neurons are confined to the mid-ventral neuropil. There is a functional segregation in motor neuron organization: cibarial muscles involved in sucking are innervated by pharyngeal motor neurons, while the proboscis muscles involved in positioning, of the proboscis are innervated by labial motor neurons. We have also observed projections of the stomodaeal nerve in the tritocerebrum.     

Genetic regulation of theAchaete-scute complex ofDrosophila melanogaster

Summary Mutants in two loci,hairy (h ⁺) andextramacrochaetae (emc ⁺), produce phenotypes corresponding to an excess of function of theachaete-scute complex (AS-C), that is, they cause the appearance of extra chaetae. These mutants, although recessive in normal flies, become dominant in the presence of extra doses of AS-C. Here we study the interactions between these three genes, in an attempt to elucidate their relationships. The results show that the insufficiency produced byh oremc mutants can be titrated by altering the number of copies of AS-C. Moreover, excess of function of AS-C produced by derepression mutants within the complex (Hairy-wing) can also be titrated by altering the number of wild type copies of⁺ oremc ⁺. These specific interactions indicate that bothh ⁺ andemc ⁺ code for repressors of AS-C that interact with theachaete andscute region of the complex respectively.     

Temporal fractal in the feeding behavior ofDrosophila melanogaster

A temporal fractal is clearly shown in the feeding behavior ofDrosophila as a self-similar pattern of locomotive velocity and inverse power law distributions of food dwelling time over the time scale range of 10³. The fractality was observed in the dwelling time distribution immediately after the fly was placed to feeding site or on inferior food in a two-choice situation. Fractality may be understood as adaptive, and an intrinsic property of animal behavior that reflects complex information processing in the CNS ofDrosophila.     

Figure-ground discrimination in the visual system ofDrosophila melanogaster

Drosophila melanogaster is able to detect a small visual object hidden in a background of identical texture, as long as there is relative motion between their retinal images. The properties of figure-ground discrimination in the walking fly are studied under experimental conditions where the positions of figure and ground oscillate sinusoidally with similar frequency and similar amplitude but with different phase. The following points have been established. (a) The average turning reaction of the stationarily walkingDrosophila depends on phase; contrary to results obtained with the flyingMusca (Reichardt and Poggio, 1979), antiphasic oscillation of figure and ground does not suppress the attrativeness of the figure. (b) A translatory response has been found which also depends on the phase difference of the oscillatory movements of figure and ground. (c) The time course of the responses and its intra- and inter-individual variability do not seem to fit into a rigid model of figure-ground discrimination.     

Differentiation capacities of the labial imaginal disc ofDrosophila melanogaster

Summary The mature labial disc, when implanted into a larva of the same age, undergoes metamorphosis along with the host and produces one lateral half of the medi- and distiproboscis. On the basis of results obtained from transplanted disc halves (including the separate peripodial membrane) a tentative fate map of the labial disc was constructed, which shows most of the presumptive mediproboscis to be located in the dorsal, and most of the presumptive distiproboscis in the ventral part of the disc. The distal protion of the peripodial membrane also contains imaginal anlagen, viz. part of the mediproboscis, prementum, and labellar cap anlagen. The involvement of this part of the peripodial membrane was checked by a careful histological analysis of labial disc development during the first ten hours after prepupation. The results were compared with the situation described forCalliphora imaginal discs.In addition, a detailed morphological analysis was made of the proboscis of the homoeotic mutantproboscipedia (pb). At 27°C,pb changes the distiproboscis into a telopodite (leg segments distal to the coxa); the (unchanged) prementum may therefore correspond to the coxa. At 15° C, the tarsus of this homoeotic telopodite is replaced to a greater or lesser extent by an arista. The present analysis thus confirms (a) the fundamental morphological correspondence of the medi- and distiproboscis with the labium of other insects, and (b) the fundamental developmental correspondence of the labial, antennal, and leg discs.K. K. was a member of the 8th International Research Group in Developmental Biology, and was the recipient of a UNESCO travel grant.)     

X-ray-induced reversion of thewhite-ivory mutant ofDrosophila melanogaster

Following X irradiation,w ⁱ reverts in oogonia and in spermatogonia. following treatment of adult females,w ⁱ reverts equally frequently in homozygotes and deficiency heterozygotes. Induced reversions are commonly recovered as clusters, indicating that they are of gonial origin. In contrast tow ⁱ , two partial reversions recombine normally withw ^ch . One of these has been tested for X-ray-induced reversion and found to be stable.A part of this investigation began while the senior author was a predoctoral trainee under Public Health Training Grant GM 701.05 at the University of California, Davis. It was completed under Utah State University Research Council Grant U-302.     

Characterization of components of Z-bands in the fibrillar flight muscle of Drosophila melanogaster

Twelve monoclonal antibodies have been raised against proteins in preparations of Z-disks isolated from Drosophila melanogaster flight muscle. The monoclonal antibodies that recognized Z-band components were identified by immunofluorescence microscopy of flight muscle myofibrils. These antibodies have identified three Z-disk antigens on immunoblots of myofibrillar proteins. Monoclonal antibodies alpha:1-4 recognize a 90-100-kD protein which we identify as alpha-actinin on the basis of cross-reactivity with antibodies raised against honeybee and vertebrate alpha-actinins. Monoclonal antibodies P:1-4 bind to the high molecular mass protein, projectin, a component of connecting filaments that link the ends of thick filaments to the Z-band in insect asynchronous flight muscles. The anti-projectin antibodies also stain synchronous muscle, but, surprisingly, the epitopes here are within the A-bands, not between the A- and Z-bands, as in flight muscle. Monoclonal antibodies Z(210):1-4 recognize a 210-kD protein that has not been previously shown to be a Z-band structural component. A fourth antigen, resolved as a doublet (approximately 400/600 kD) on immunoblots of Drosophila fibrillar proteins, is detected by a cross reacting antibody, Z(400):2, raised against a protein in isolated honeybee Z-disks. On Lowicryl sections of asynchronous flight muscle, indirect immunogold staining has localized alpha-actinin and the 210-kD protein throughout the matrix of the Z-band, projectin between the Z- and A-bands, and the 400/600-kD components at the I-band/Z-band junction. Drosophila alpha-actinin, projectin, and the 400/600-kD components share some antigenic determinants with corresponding honeybee proteins, but no honeybee protein interacts with any of the Z(210) antibodies.