Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “wing”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1997

Hedgehog activity, independent of decapentaplegic, participates in wing disc patterning.

In the Drosophila wing imaginal disc, the Hedgehog (Hh) signal molecule induces the expression of decapentaplegic (dpp) in a band of cells abutting the anteroposterior (A/P) compartment border. It has been proposed that Dpp organizes the patterning of the entire wing disc. We have tested this proposal by studying the response to distinct levels of ectopic expression of Hh and Dpp, using the sensory organ precursors (SOPs) of the wing and notum and the presumptive wing veins as positional markers. Here, we show that Dpp specifies the position of most SOPs in the notum and of some of them in the wing. Close to the A/P compartment border, however, SOPs are specified by Hh rather than by Dpp alone. We also show that late signaling by Hh, after setting up dpp expression, is responsible for the formation of vein 3 and the scutellar region, and also for the determination of the distance between veins 3 and 4. One of the genes that mediates the Hh signal is the zinc-finger protein Cubitus interruptus (Ci). These results indicate that Hh has a Dpp-independent morphogenetic effect in the region of the wing disc near the A/P border.

Animals↗
PubMed2000

Relationships between extramacrochaetae and Notch signalling in Drosophila wing development.

The function of extramacrochaetae is required during the development of the Drosophila wing in processes such as cell proliferation and vein differentiation. extramacrochaetae encodes a transcription factor of the HLH family, but unlike other members of this family, Extramacrochaetae lacks the basic region that is involved in interaction with DNA. Some phenotypes caused by extramacrochaetae in the wing are similar to those observed when Notch signalling is compromised. Furthermore, maximal levels of extramacrochaetae expression in the wing disc are restricted to places where Notch activity is higher, suggesting that extramacrochaetae could mediate some aspects of Notch signalling during wing development. We have studied the relationships between extramacrochaetae and Notch in wing development, with emphasis on the processes of vein formation and cell proliferation. We observe strong genetic interaction between extramacrochaetae and different components of the Notch signalling pathway, suggesting a functional relationship between them. We show that the higher level of extramacrochaetae expression coincides with the domain of expression of Notch and its downstream gene Enhancer of split-m(beta). The expression of extramacrochaetae at the dorso/ventral boundary and in boundary cells between veins and interveins depends on Notch activity. We propose that at least during vein differentiation and wing margin formation, extramacrochaetae is regulated by Notch and collaborates with other Notch-downstream genes such as Enhancer of split-m(beta).

Animals↗
PubMed2001

Context-dependent relationships between the BMPs gbb and dpp during development of the Drosophila wing imaginal disk.

The Drosophila BMP5/6/7/8 homolog, glass bottom boat (gbb), has been shown to be involved in proliferation and vein patterning in the wing disk. To better understand the roles for gbb in wing development, as well as its relationship with the Drosophila BMP2/4 homolog decapentaplegic (dpp), we have used clonal analysis to define the functional foci of gbb during wing development. Our results show that gbb has both local and long-range functions in the disk that coincide both spatially and functionally with the established functions of dpp, suggesting that both BMPs contribute to the same processes during wing development. Indeed, comparison of the mutant phenotypes of dpp and gbb hypomorphs and null clones shows that both BMPs act locally along the longitudinal and cross veins to affect the process of vein promotion during pupal development, and long-range from a single focus along the A/P compartment boundary to affect the processes of disk proliferation and vein specification during larval development. Moreover, we show that duplications of dpp are able to rescue many of the phenotypes associated with gbb mutants and clones, indicating that the functions of gbb are at least partially redundant with those of dpp. While this relationship is similar to that described for dpp and the BMP screw (scw) in the embryo, we show that the mechanisms underlying both local and long-range functions of gbb and dpp in the wing are different. For the local foci, gbb function is confined to the regions of the veins that require the highest levels of dpp signaling, suggesting that gbb acts to augment dpp signaling in the same way as scw is proposed to do in the embryo. However, unlike scw-dependent signals in the embryo, these gbb signals are not transduced by the Type I receptor saxophone (sax), thus, the cooperativity between gbb and dpp is not achieved by signaling through distinct receptor complexes. For the long-range focus along the A/P compartment boundary, gbb function does not appear to affect the high point of the dpp gradient, but, rather, appears to be required for low points, which is the reciprocal of the relationship between dpp and scw in the embryo. Moreover, these functions of gbb also do not require the Type I receptor sax. Given these results, we conclude that the relationships between gbb and dpp in the wing disk represent novel paradigms for how multiple BMP ligands signal during development, and that signaling by multiple BMPs involves a variety of different inter-ligand relationships that depend on the developmental context in which they act.

Animals↗
PubMed2002

Dpp signalling is a key effector of the wing-body wall subdivision of the Drosophila mesothorax.

During development, the imaginal wing disc of Drosophila is subdivided along the proximal-distal axis into different territories that will give rise to body wall (notum and mesothoracic pleura) and appendage (wing hinge and wing blade). Expression of the Iroquois complex (Iro-C) homeobox genes in the most proximal part of the disc defines the notum, since Iro-C(-) cells within this territory acquire the identity of the adjacent distal region, the wing hinge. Here we analyze how the expression of Iro-C is confined to the notum territory. Neither Wingless signalling, which is essential for wing development, nor Vein-dependent EGFR signalling, which is needed to activate Iro-C, appear to delimit Iro-C expression. We show that a main effector of this confinement is the TGFbeta homolog Decapentaplegic (Dpp), a molecule known to pattern the disc along its anterior-posterior axis. At early second larval instar, the Dpp signalling pathway functions only in the wing and hinge territories, represses Iro-C and confines its expression to the notum territory. Later, Dpp becomes expressed in the most proximal part of the notum and turns off Iro-C in this region. This downregulation is associated with the subdivision of the notum into medial and lateral regions.

Animals↗
PubMed2002

Subdivision of the Drosophila wing imaginal disc by EGFR-mediated signaling.

Growth and patterning of the Drosophila wing imaginal disc depends on its subdivision into dorsoventral (DV) compartments and limb (wing) and body wall (notum) primordia. We present evidence that both the DV and wing-notum subdivisions are specified by activation of the Drosophila Epidermal Growth Factor Receptor (EGFR). We show that EGFR signaling is necessary and sufficient to activate apterous (ap) expression, thereby segregating the wing disc into D (ap-ON) and V (ap-OFF) compartments. Similarly, we demonstrate that EGFR signaling directs the expression of Iroquois Complex (Iro-C) genes in prospective notum cells, rendering them distinct from, and immiscible with, neighboring wing cells. However, EGFR signaling acts only early in development to heritably activate ap, whereas it is required persistently during subsequent development to maintain Iro-C gene expression. Hence, as the disc grows, the DV compartment boundary can shift ventrally, beyond the range of the instructive EGFR signal(s), in contrast to the notum-wing boundary, which continues to be defined by EGFR input.

Animals↗
PubMed2002

Control of growth and patterning of the Drosophila wing imaginal disc by EGFR-mediated signaling.

The subdivision of the Drosophila wing imaginal disc into dorsoventral (DV) compartments and limb-body wall (wing-notum) primordia depends on Epidermal Growth Factor Receptor (EGFR) signaling, which heritably activates apterous (ap) in D compartment cells and maintains Iroquois Complex (Iro-C) gene expression in prospective notum cells. We examine the source, identity and mode of action of the EGFR ligand(s) that specify these subdivisions. Of the three known ligands for the Drosophila EGFR, only Vein (Vn), but not Spitz or Gurken, is required for wing disc development. We show that Vn activity is required specifically in the dorsoproximal region of the wing disc for ap and Iro-C gene expression. However, ectopic expression of Vn in other locations does not reorganize ap or Iro-C gene expression. Hence, Vn appears to play a permissive rather than an instructive role in organizing the DV and wing-notum segregations, implying the existance of other localized factors that control where Vn-EGFR signaling is effective. After ap is heritably activated, the level of EGFR activity declines in D compartment cells as they proliferate and move ventrally, away from the source of the instructive ligand. We present evidence that this reduction is necessary for D and V compartment cells to interact along the compartment boundary to induce signals, like Wingless (Wg), which organize the subsequent growth and differentiation of the wing primordium.

Animals↗
PubMed2003

The influence of wing-wake interactions on the production of aerodynamic forces in flapping flight.

We used two-dimensional digital particle image velocimetry (DPIV) to visualize flow patterns around the flapping wing of a dynamically scaled robot for a series of reciprocating strokes starting from rest. The base of the wing was equipped with strain gauges so that the pattern of fluid motion could be directly compared with the time history of force production. The results show that the development and shedding of vortices throughout each stroke are highly stereotyped and influence force generation in subsequent strokes. When a wing starts from rest, it generates a transient force as the leading edge vortex (LEV) grows. This early peak, previously attributed to added-mass acceleration, is not amenable to quasi-steady models but corresponds well to calculations based on the time derivative of the first moment of vorticity within a sectional slice of fluid. Forces decay to a stable level as the LEV reaches a constant size and remains attached throughout most of the stroke. The LEV grows as the wing supinates prior to stroke reversal, accompanied by an increase in total force. At stroke reversal, both the LEV and a rotational starting vortex (RSV) are shed into the wake, forming a counter-rotating pair that directs a jet of fluid towards the underside of the wing at the start of the next stroke. We isolated the aerodynamic influence of the wake by subtracting forces and flow fields generated in the first stroke, when the wake is just developing, from those produced during the fourth stroke, when the pattern of both the forces and wake dynamics has reached a limit cycle. This technique identified two effects of the wake on force production by the wing: an early augmentation followed by a small attenuation. The later decrease in force is consistent with the influence of a decreased aerodynamic angle of attack on translational forces caused by downwash within the wake and is well explained by a quasi-steady model. The early effect of the wake is not well approximated by a quasi-steady model, even when the magnitude and orientation of the instantaneous velocity field are taken into account. Thus, the wake capture force represents a truly unsteady phenomenon dependent on temporal changes in the distribution and magnitude of vorticity during stroke reversal.

Animals↗
PubMed2004

The effect of advance ratio on the aerodynamics of revolving wings.

Recent studies have demonstrated that a quasi-steady model closely matches the instantaneous force produced by an insect wing during hovering flight. It is not clear, however, if such methods extend to forward flight. In this study we use a dynamically scaled robotic model of the fruit fly Drosophila melanogaster to investigate the forces produced by a wing revolving at constant angular velocity while simultaneously translating at velocities appropriate for forward flight. Because the forward and angular velocities were constant wing inertia was negligible, and the measured forces can be attributed to fluid dynamic phenomena. The combined forward and revolving motions of the wing produce a time-dependent free-stream velocity profile, which suggests that added mass forces make a contribution to the measured forces. We find that the forces due added mass make a small, but measurable, component of the total force and are in excellent agreement with theoretical values. Lift and drag coefficients are calculated from the force traces after subtracting the contributions due to added mass. The lift and drag coefficients, for fixed angle of attack, are not constant for non-zero advance ratios, but rather vary in magnitude throughout the stroke. This observation implies that modifications of the quasi-steady model are required in order to predict accurately the instantaneous forces produced during forward flight. We show that the dependence of the lift and drag coefficients upon advance ratio and stroke position can be characterized effectively in terms of the tip velocity ratio--the ratio of the chordwise components of flow velocity at the wing tip due to translation and revolution. On this basis we develop a modified quasi-steady model that can account for the varying magnitudes of the lift and drag coefficients. Our model may also resolve discrepancies in past measurements of wing performance based on translational and revolving motion.

Animals↗
PubMed2000

The hind wing of the desert locust (Schistocerca gregaria Forskål). I. Functional morphology and mode of operation.

Detailed morphological investigation, mechanical testing and high-speed cinematography and stroboscopic examination of desert locusts, Schistocerca gregaria, in flight show that their hind wings are adapted to deform cyclically and automatically through the wing stroke and that the deformations are subtly dependent on the wings' structure: their shape, venation and vein design and the local properties of the membrane. The insects predominantly fly fast forwards, generating most force on the downstroke, and the hind wings generate extra lift by peeling apart at the beginning of the downstroke and by developing a cambered section during the stroke's translation phase through the 'umbrella effect' - an automatic consequence of the active extension of the wings' expanded posterior fan. Bending experiments indicate that most of the hind wing is more rigid to forces from below than from above and demonstrate that the membrane acts as a stressed skin to stiffen the structure.

Animals↗
PubMed2002

The locust tegula: kinematic parameters and activity pattern during the wing stroke.

The tegula is a complex, knob-shaped sense organ associated with the base of the locust wing. Despite a detailed knowledge of its role in flight motor control, little is known about the relationship between the stroke parameters of the wing, movement of the tegula organ and the pattern of tegula activity. In this study, therefore, the kinematic parameters of the fore- and hindwings were investigated with respect to the tegula activity pattern during tethered flight. The following results were obtained. (i) The tegula moves through a complex three-dimensional trajectory during the wing stroke, involving inclination and rotation about its longitudinal axis. (ii) The kinematic parameters of tegula movement are phase-locked to the wing stroke and vary in conjunction with wing stroke parameters such as amplitude and cycle period. (iii) In accordance with these phase-locked kinematics, both the onset of tegula activity with respect to the downstroke (latency) and the discharge of the organ (burst duration and amplitude) vary in conjunction with downstroke movement and cycle period, resulting in an (almost) constant phase of tegula activation during the stroke cycle. (iv) The pattern of tegula activity during flight is largely independent of stroke amplitude. (v) The latency, burst duration and amplitude of tegula activity are strongly related to the angular velocity of the wing during the downstroke, with latency reaching a steady minimum value at higher angular velocities. The data suggest that the tegula encodes the timing and velocity of the downstroke and that it may be involved in the control of the stroke's angular velocity.

Animals↗
PubMed2002

The aerodynamic effects of wing rotation and a revised quasi-steady model of flapping flight.

We used a dynamically scaled model insect to measure the rotational forces produced by a flapping insect wing. A steadily translating wing was rotated at a range of constant angular velocities, and the resulting aerodynamic forces were measured using a sensor attached to the base of the wing. These instantaneous forces were compared with quasi-steady estimates based on translational force coefficients. Because translational and rotational velocities were constant, the wing inertia was negligible, and any difference between measured forces and estimates based on translational force coefficients could be attributed to the aerodynamic effects of wing rotation. By factoring out the geometry and kinematics of the wings from the rotational forces, we determined rotational force coefficients for a range of angular velocities and different axes of rotation. The measured coefficients were compared with a mathematical model developed for two-dimensional motions in inviscid fluids, which we adapted to the three-dimensional case using blade element theory. As predicted by theory, the rotational coefficient varied linearly with the position of the rotational axis for all angular velocities measured. The coefficient also, however, varied with angular velocity, in contrast to theoretical predictions. Using the measured rotational coefficients, we modified a standard quasi-steady model of insect flight to include rotational forces, translational forces and the added mass inertia. The revised model predicts the time course of force generation for several different patterns of flapping kinematics more accurately than a model based solely on translational force coefficients. By subtracting the improved quasi-steady estimates from the measured forces, we isolated the aerodynamic forces due to wake capture.

Animals↗
PubMed2005

Gene expression during Drosophila wing morphogenesis and differentiation.

The simple cellular composition and array of distally pointing hairs has made the Drosophila wing a favored system for studying planar polarity and the coordination of cellular and tissue level morphogenesis. We carried out a gene expression screen to identify candidate genes that functioned in wing and wing hair morphogenesis. Pupal wing RNA was isolated from tissue prior to, during, and after hair growth and used to probe Affymetrix Drosophila gene chips. We identified 435 genes whose expression changed at least fivefold during this period and 1335 whose expression changed at least twofold. As a functional validation we chose 10 genes where genetic reagents existed but where there was little or no evidence for a wing phenotype. New phenotypes were found for 9 of these genes, providing functional validation for the collection of identified genes. Among the phenotypes seen were a delay in hair initiation, defects in hair maturation, defects in cuticle formation and pigmentation, and abnormal wing hair polarity. The collection of identified genes should be a valuable data set for future studies on hair and bristle morphogenesis, cuticle synthesis, and planar polarity.

Animals↗
PubMed2004

Spatial structuring of Triatoma infestans (Hemiptera, Reduviidae) populations from northwestern Argentina using wing geometric morphometry.

Wing geometric morphometry was used to study the spatial structuring of populations of Triatoma infestans from different villages, ecotopes, and sites within a village in northwestern Argentina. A total of 308 male and 197 female wings of T. infestans collected from peridomestic and domestic ecotopes in March 2000 was analyzed. On average, female bugs had a significantly larger wing size than males. Triatomines collected from domiciles or structures associated with chickens had larger wings than bugs collected from goat or pig corrals. The wing size of bugs did not differ significantly between villages. Discriminant analyses of wing shape showed significant divergence between villages, ecotopes, and individual collection sites. The study of metric variation of males between sites belonging to the same ecotope also revealed significant heterogeneity. Indeed, within the same section of the village the difference between two goat corrals was sometimes greater than that between neighboring goat and pig corrals. Thus, morphometric heterogeneity within villages may be the result not only of ecotope and host associations, but also of physical isolation between subunits. The strong structuring of T. infestans populations in the study area indicates that recolonization could be traced back to a small geographic source.

Animals↗
PubMedDate not supplied

[Change in the system of wing venation of Drosophila melanogaster under heat shock and selection].

A change in the system of wing venation of Drosophila melanogaster appeared in response to heat shock and positive selection pressure directed to restoring the normal formation of wing radial vein, L2, that had been violated earlier by the recessive mutation of radius incompletes. Positive selection was effective, L2 having been formed correctly and completely to 35 generation. Besides, (+)-selection was accompanied by appearance of a small fragment of an additional vein at the wing tip. Selection directed to increase of size of this fragment resulted in the sufficient changes in the system of wing venation as a whole. It is suggested that, during evolution, transformation of wing venation of Drosophila was effected by the change of the way of prepattern realization, whereas the cells of wing plate continued to allow the formation of veins practically over a whole area.

Animals↗
PubMed1987

The guidance of axons from transplanted neurons through aneural Drosophila wings.

The sensory neurons of the wing of Drosophila arise during the first 24 hr of metamorphosis, and their axons converge to form a stereotyped set of nerves projecting proximally from the peripherally located cell bodies through the wing and towards the CNS. To better characterize the cues guiding this stereotyped axon outgrowth, we have performed a series of transplantation studies in which neurons from a variety of sources (wing, eye, antenna, and leg disks) were placed into mutant, aneural wings. Axons growing from such implants in effect assay the host wing for the presence and location of guidance cues. Our results show, first, that such axons prefer to grow in the normal, proximal direction and, second, that they prefer to grow along the approximate site of one of the normal nerves, that of the third longitudinal vein. It therefore appears that the aneural wing epithelium contains cues capable of directing both the polarity and the location of axonal outgrowth. These cues are relatively non-specific, in that a variety of neuronal types are capable of responding to them.

Animals↗
PubMed1985

Retinoic acid and pattern formation in the developing chick wing: SEM and quantitative studies of early effects on the apical ectodermal ridge and bud outgrowth.

When retinoic acid is locally applied to the anterior margin of developing chick wing buds on ion-exchange beads, dose-dependent changes in the skeletal pattern result. At low doses, additional digits develop. At high doses, there is thinning of the symmetrical wing. Local application of retinoic acid to the apex of the bud also leads to pattern changes, but in contrast normal wing patterns are almost always obtained following application posteriorly. These effects are manifest at 6-7 days after the operation although only a brief exposure (14-20 h) to retinoic acid is required. Therefore the morphology of wing buds was studied at shorter times after the start of treatment. The local application of retinoic acid to the wing bud margin leads to changes in extent of the apical ridge that can be detected at 24 h after application. The behaviour of the apical ridge with varying doses and positions of retinoic acid application has been analysed quantitatively and dose response curves obtained. At low doses of retinoic acid, the length of the apical ridge increases or remains constant, but then progressively decreases with higher doses. The progressive obliteration of the ridge starts first near the bead and then involves more distant parts of the bud. Thus the region of the ridge affected depends on the position at which the retinoic acid is applied. We propose that these effects on the apical ridge reflect dose-dependent responses to the local concentration of retinoic acid that varies with distance from the source. At high doses, the apical ridge disappears but at low doses it is maintained. Since grafts of polarizing region tissue also have a graded effect on ridge morphology, a possible interpretation of the retinoic acid effects is that tissue adjacent to the source is converted into polarizing region tissue. Alternatively, retinoic acid may act directly on the ridge cells. The changes in the extent of the apical ridge produced by retinoic acid lead to different forms of bud outgrowth. The form of the outgrowth depends on the dose of retinoic acid, the position of application and the interaction between the effects of the local source of retinoic acid and those of the polarizing region of the host bud. These considerations give some insights into why anterior application of retinoic acid leads to the development of additional digits whereas posterior application generally gives normal wings.

Animals↗
PubMed1984

Development of the apical ectodermal ridge in the chick wing bud.

Histological examination of the stage-18 to stage-23 chick wing bud apex revealed the following. Initially, the wing bud was covered by a cuboidal to columnar epithelium with an overlying periderm. Thickening of the apical ectoderm was not obvious until late stage 18 (36 pairs of somites), after the appearance of the wing bud. At late stage 18, cells of the inner layer of ectoderm had elongated slightly along an axis perpendicular to the epithelial-mesenchymal interface. Well-defined apical ectodermal ridge morphology, i.e., pseudostratified columnar epithelium with an overlying periderm, was not apparent until stage 20. Subsequently the ridge lengthened along the anteroposterior perimeter of the wing bud. We demonstrated histologically that the apical ectodermal ridge of the wing bud was asymmetric with respect to the anteroposterior axis, in that there was more ridge associated with posterior mesoderm. Other observations include the spatial and temporal location of a groove in the base of the thickest part of the ridge. The groove can be correlated with the specification of distal wing elements. The groove was first seen at stage 20 and became more prominent through stage 23. An anteroposterior progression of ectodermal cell death was also observed. This began at late stage 18 and continued through each of the stages examined.

Animals↗
PubMed1982

The pattern of campaniform sensilla on the wing and haltere of Drosophila melanogaster and several of its homeotic mutants.

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.

Alleles↗