Extent and properties of the regeneration field in the larval legs of cockroaches (Leucophaea maderae)

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 69-79
Author(s):  
Horst Bohn
Keyword(s):  
Abdominal Segment ◽  
Anterior Margin ◽  
Posterior Border ◽  
Anterior Border ◽  
Leucophaea Maderae ◽  
Anterior Half ◽  
Regenerative Ability ◽  
Transplantation Experiments ◽  
Anterior Posterior

The investigation of the regeneration field of the larval legs of cockroaches (Leucophaea maderae), which commenced in a previous paper with extirpation experiments, has been continued by transplantation experiments. The extirpation experiments showed that there are two regions near the leg which are indispensable for leg regeneration: the basal sclerites, and the membranous region extending behind the leg up to the spiracle of the next segment, called ‘leg-inducing membrane’ (LIM). The LIM is followed by ‘sclerite-inducing membrane’ (SIM) which, upon contact with sclerites, only allows formation of sclerite structures. The results of the extirpation experiments have been confirmed by transplantation experiments. When the whole leg including the basal sclerites is removed, no leg regeneration occurs. The regenerative ability can be restored by implantation of part of the basal sclerites (for instance, the trochantin), but leg regeneration takes place only when the implantation area is covered by LIM. When the sclerites are transplanted to a region which is covered by SIM only additional basal sclerites are formed. Whole sets of basal sclerites have been implanted at different distances behind the uninjured hindleg. Additional legs are regenerated only in the anterior half of the membranous field extending between the hindleg and the first abdominal segment. Thus, there is adistribution of LIM and SIM in the region of the hindleg, similar to that near the midleg. Whole sets of basal sclerites have been implanted at various sites on the dorsal or ventral surfaces of the abdomen. Legs are formed on both surfaces, but only when the transplanted sclerites contact the intersegmental membranes. This means that the intersegmental membranes of the abdomen also have leg-inducing capacities. The implantation of a trochantin into a field of LIM is followed by the development of two regenerates - a normal one at the posterior border of the field, and one with reverse anterior-posterior polarity at the anterior border. When the trochantin is transplantedtogether with the praecoxa in a similar way, only one normal regenerate is formed at theposterior margin of the trochantin. The praecoxa prevents contact of the anterior margin of the trochantin with LIM, and contact of the anterior margin of the praecoxa with LIM does not promote leg regeneration.

Extent and properties of the regeneration field in the larval legs of cockroaches (Leucophaea maderae)

Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 557-572
Author(s):  
Horst Bohn
Keyword(s):  
Anterior Part ◽  
Posterior Region ◽  
Anterior Region ◽  
Posterior Border ◽  
Anterior Border ◽  
Experimental Conditions ◽  
Leucophaea Maderae ◽  
Reversed Polarity ◽  
Anterior Posterior

Extirpation experiments have been performed on the larvae of cockroaches (Leucophaea maderae) to determine the extent and properties of the regeneration field of the legs of these insects. The distal segments, including the coxa, may all be removed without loss of regenerative capability; but regenerative capability eventually disappears if more proximal parts are removed. There are two regions adjoining the coxa anteriorly and posteriorly which are both important for leg regeneration. The anterior region consists of the sclerotized basal parts of the leg mainly formed by the trochantin and the praecoxa. The posterior region is an unsclerotized membranous area extending from the posterior border of the coxa to the anterior border of the next segment. This membrane is called ‘leg-inducing membrane’. If only one of these two regions is present, no leg regeneration will occur. The interaction of both parts is necessary to allow the formation of a complete leg. An extra leg with reversed anterior–posterior polarity is formed when the ‘leg-inducing membrane’ of one segment is brought into contact with the sclerites of the following segment after extirpation of the membranous area which normally separates them. This membranous area, which represents the most anterior part of a segment, is called ‘sclerite-inducing membrane’, for if the basal sclerites or part of them are combined with this membrane only sclerites are formed, either in normal or reversed polarity depending on the experimental conditions.

VIII.—On the Pectoral Fin of Cœlacanthus

1901 ◽  
Vol 8 (2) ◽  
pp. 71-72 ◽  
Author(s):  
Edgar D. Wellburn
Keyword(s):  
New South ◽  
New South Wales ◽  
Geological Survey ◽  
Pectoral Fin ◽  
Anterior Border ◽  
Pectoral Fins ◽  
Anterior Half ◽  
South Wales ◽  
Fin Rays ◽  
Distal Border

Among the fossil fishes of the Talbragar Beds (Jurassic?) described by Dr. A. Smith Woodward in a memoir of the Geological Survey of New South Wales (1895), there is the ventral portion of the abdominal region of a Cœlacanth fish, having one of the pectoral fins well shown. The fin is shown in counterpart, and is thus described:— “It exhibits, as usual, the characteristic obtuse lobation and the large fringe of articulated attenuated dermal rays, and is unique in displaying some of the eudoskeletal supporting bones. These elements seem to have been well ossified, though with persistent cartilage internally. At the base of the fin there occurs a broken fragment of bone1 incapable of determination; but in the lobe of the fin itself there is a series of four well-defined, hourglass-shaped supports. Of these bones the anterior three are much elongated, and nearly equally slender, while the fourth is much more robust and expanded at its distal end. The four elements radiate from the anterior half of the base of the fin; and it seems very probable that some smaller cartilage behind and near the distal border of the lobe have disappeared from lack of ossification. The fin-rays gradually increase in length from the anterior border to the middle of the lobe, whence they decrease again backwards, and finally become extremely delicate.”

A GYNANDROMORPH OF RACHISPODA SUBPILIGERA (MALLOCH) (DIPTERA: SPHAEROCERIDAE), WITH NOTES ON ASYMMETRY, CIRCUMVERSION, AND THE STRUCTURE OF THE MALE POSTABDOMEN

1992 ◽  
Vol 124 (4) ◽  
pp. 729-735 ◽  
Author(s):  
Terry A. Wheeler
Keyword(s):  
Abdominal Segment ◽  
Developmental Process ◽  
Direct Consequence ◽  
Male And Female ◽  
Posterior Division ◽  
Anterior Posterior

AbstractA gynandromorph of Rachispoda subpiligera (Malloch) is described. The specimen exhibits both bilateral and anterior/posterior division of male and female genitalic components. Abdominal segment 5 is male, segments 6 and 7 are bilaterally divided into male (right) and female (left) halves, and segments 8–11 are female. Comparison of male and female components supports the view that the large, asymmetrical sclerite posterior to sternite 5 in male Sphaeroceridae is synsternite 6 + 7. Circumversion of the genitalia, normally seen in male segments 8–11, is absent, although male components of segments 6 and 7 exhibit asymmetry normally associated with circumversion. This suggests that asymmetry of sternites 6 and 7 is a developmental process independent of circumversion, not a direct consequence of circumversion.

The spatial and temporal dynamics of Sax1 (CHox3) homeobox gene expression in the chick's spinal cord

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1817-1828 ◽  
Author(s):  
P. Spann ◽  
M. Ginsburg ◽  
Z. Rangini ◽  
A. Fainsod ◽  
H. Eyal-Giladi ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Homeobox Gene ◽  
Primitive Streak ◽  
Neural Plate ◽  
Transverse Plane ◽  
Posterior Border ◽  
Anterior Border ◽  
Spatial And Temporal Dynamics ◽  
Specific Localization

Sax1 (previously CHox3) is a chicken homeobox gene belonging to the same homeobox gene family as the Drosophila NK1 and the honeybee HHO genes. Sax1 transcripts are present from stage 2 H&H until at least 5 days of embryonic development. However, specific localization of Sax1 transcripts could not be detected by in situ hybridization prior to stage 8-, when Sax1 transcripts are specifically localized in the neural plate, posterior to the hindbrain. From stages 8- to 15 H&H, Sax1 continues to be expressed only in the spinal part of the neural plate. The anterior border of Sax1 expression was found to be always in the transverse plane separating the youngest somite from the yet unsegmented mesodermal plate and to regress with similar dynamics to that of the segregation of the somites from the mesodermal plate. The posterior border of Sax1 expression coincides with the posterior end of the neural plate. In order to study a possible regulation of Sax1 expression by its neighboring tissues, several embryonic manipulation experiments were performed. These manipulations included: removal of somites, mesodermal plate or notochord and transplantation of a young ectopic notochord in the vicinity of the neural plate or transplantation of neural plate sections into the extraembryonic area. The results of these experiments revealed that the induction of the neural plate by the mesoderm has already occurred in full primitive streak embryos, after which Sax1 is autonomously regulated within the spinal part of the neural plate.

Regeneration in the anterior—posterior axis of the insect thoracic segment

Development ◽  
1986 ◽  
Vol 98 (1) ◽  
pp. 137-165
Author(s):  
Vernon French ◽  
Tamara F. Rowlands
Keyword(s):  
Abdominal Segment ◽  
Adjacent Tissue ◽  
Local Pattern ◽  
Shortest Route ◽  
Polar Coordinate ◽  
Coordinate Model ◽  
Deletion Pattern ◽  
Boundary Model ◽  
Third Line ◽  
Anterior Posterior

After removal of a transverse strip of ventral thorax from the beetle, Tenebrio molitor, interaction occurred between epidermis posterior to the mesothoracic leg and that anterior to the metathoracic leg. Depending on the size and position of the excision, this interaction resulted in either the regeneration of the extirpated tissue or its replacement by an A/P reversed pattern of sclerites and supernumerary leg. By either route, local pattern continuity was restored between the normal meso- and metathoracic legs. Similarly, when a leg plus adjacent tissue was extirpated, continuity was restored by leg regeneration or by formation of an A/P reversed duplication of sclerites. The results of these strip excisions can be understood in terms of two current models of the ventral thorax (the Boundary Model and the Polar Coordinate Model), each of which postulates a distinct compartment or region intervening between the epidermis surrounding the bases of successive legs. However, the models do not explain the large differences in the frequency of formation of the duplication/deletion pattern after excisions of different widths. The results are also compatible with a different model, involving an A–P sequence of positional values similar to that proposed for the abdominal segment. Regeneration would restore continuity within the sequence by the shortest route, forming either the midsegment (including the leg) or the intersegmental region. The meso- and metathorax differ in the structure of the ventral sclerites and in the segmentation of the tarsus of the leg. The structures regenerated after the various excisions show that the segment border is not crossed during regeneration and indicate that an A/P compartment border running through the leg is usually also respected. There is no sign, however, of a third line of lineage restriction that would indicate a subdivision of the segment into three compartments (as proposed in the Boundary Model).

scholarly journals BARE SPOT LOCATION IN GLENOID CAVITY: COMPARISON BETWEEN ARTHROSCOPY AND CT SCAN

2020 ◽  
Vol 28 (5) ◽  
pp. 243-246
Author(s):  
MAX ROGÉRIO FREITAS RAMOS ◽  
PEDRO FILGUEIRAS HIDALGO ◽  
DIOGO FAGUNDES ◽  
YONDER ARCHANJO CHING SAN JUNIOR
Keyword(s):  
Posterior Margin ◽  
Three Dimensional ◽  
Glenoid Cavity ◽  
Posterior Border ◽  
Posterior Edge ◽  
Anterior Border ◽  
Level Of Evidence ◽  
Injury Repair ◽  
Bare Spot ◽  
Dimensional Reconstruction

ABSTRACT Objective: To assess whether Bare Spot is previously displaced by proportion (MEASURE BP-A × 1.25/MEASURE BP-P = 1). Methods: 35 patients with surgical indication for rotator cuff injury repair were evaluated. The distances from the Bare Spot to the anterior edge of the glenoid cavity (BS-A) and to the posterior edge (BS-P) were measured by arthroscopy and computed tomography with three-dimensional reconstruction of the scapula. Results: The distance from the Bare Spot to the anterior border (BS-A tc) was 11.6 mm with a median 12 mm; The distance to the posterior border (BS-P tc) was on average 15.5 mm with a median 15 mm. The distances from BS to anterior cavity edge measured by arthroscopy were on average (BS-A video) 12.25 mm with a median of 12 mm, and from BS to posterior edge (BS-P video) 16.25 mm on average with median 16 mm (p < 0.005). Conclusion: Bare Spot is displaced anteriorly at a proportion of 40% of the anterior margin and 60% of the posterior margin. Level of Evidence II - Development of diagnostic criteria on consecutive patients (with universally applied reference “gold standard”).

Retinoic acid induces a pattern of digits in anterior half wing buds that lack the zone of polarizing activity

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 863-867 ◽  
Author(s):  
G. Eichele
Keyword(s):  
Retinoic Acid ◽  
Cell Fate ◽  
Anterior Margin ◽  
Limb Bud ◽  
Posterior Half ◽  
Anterior Half ◽  
Zone Of Polarizing Activity

Wing buds whose posterior half is excised, develop into wings lacking distal structures. However, such experimentally generated preaxial half wing buds can be rescued by implanting a retinoic-acid-releasing bead at their anterior margin. The polarity of the pattern that originates from preaxial half wing buds is reversed. For example, instead of a 234 digit pattern typical for normal wings, the order of digits is 432. This result implies that retinoic acid has the capacity to reprogram anterior limb bud tissue, and that the resulting change in cell fate does not depend on the presence of posterior tissue regions such as the zone of polarizing activity (ZPA).

Role of dHAND in the anterior-posterior polarization of the limb bud: implications for the Sonic hedgehog pathway

Development ◽  
2000 ◽  
Vol 127 (10) ◽  
pp. 2133-2142 ◽  
Author(s):  
M. Fernandez-Teran ◽  
M.E. Piedra ◽  
I.S. Kathiriya ◽  
D. Srivastava ◽  
J.C. Rodriguez-Rey ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Limb Development ◽  
Mirror Image ◽  
Limb Bud ◽  
Bhlh Transcription Factor ◽  
Cardiovascular Development ◽  
Anterior Border ◽  
Lateral Plate ◽  
Shh Pathway ◽  
Anterior Posterior

dHAND is a basic helix-loop-helix (bHLH) transcription factor essential for cardiovascular development. Here we analyze its pattern of expression and functional role during chick limb development. dHAND expression was observed in the lateral plate mesoderm prior to emergence of the limb buds. Coincident with limb initiation, expression of dHAND became restricted to the posterior half of the limb bud. Experimental procedures that caused mirror-image duplications of the limb resulted in mirror-image duplications of the pattern of dHAND expression along the anterior-posterior axis. Retroviral overexpression of dHAND in the limb bud produced preaxial polydactyly, corresponding to mild polarizing activity at the anterior border. At the molecular level, misexpression of dHAND caused ectopic activation of members of the Sonic hedgehog (Shh) pathway, including Gli and Patched, in the anterior limb bud. A subset of infected embryos displayed ectopic anterior activation of Shh. Other factors implicated in anterior-posterior polarization of the bud such as the most 5′ Hoxd genes and Bmp2 were also ectopically activated at the anterior border. Our results indicate a role for dHAND in the establishment of anterior-posterior polarization of the limb bud.

Gross anatomical features of the sternum of green-winged macaw (Ara Chloroptera)

2015 ◽  
Vol 49 (6) ◽  
Author(s):  
A. R. Sreeranjini ◽  
N. Ashok ◽  
V. R. Indu ◽  
K. M. Lucy ◽  
S. Maya ◽  
...  
Keyword(s):  
Anterior Extremity ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Morphological Features ◽  
Posterior Border ◽  
Posterior Half ◽  
Lateral Border ◽  
Convex Surfaces ◽  
Anatomical Features ◽  
Anterior Half

The present study was conducted on the sternum of an eight year old, male Green-winged Macaw. The sternum was quadrilateral with dorsal concave and ventral convex surfaces and four borders. The dorsal surface presented numerous pneumatic foramina. The ventral surface furnished a large, boat shaped keel. The anterior extremity showed two facets for coracoid. The anterior and posterior borders were convex. The lateral border on either side presented six costal facets. Two distinct oval foramina were seen near the posterior border. Craniolateral processes were short and stump-like. Caudolateral processes fused with the median trabecula on either side. The rostrum was distinct. The morphological features of the sternum of Green-winged Macaw conformed to that of flying group of birds. It was almost similar to that of goose in its anterior half and to that of pigeon in its posterior half.

scholarly journals A New Formica from Northern Maine, with a Discussion of its Supposed Type of Social Parasitism (Hymenoptera: Formicidae)

1949 ◽  
Vol 81 (1) ◽  
pp. 13-17 ◽  
Author(s):  
M. W. Wing
Keyword(s):  
Social Parasitism ◽  
Isosceles Triangle ◽  
Frontal Area ◽  
Medium Size ◽  
Posterior Border ◽  
Uneven Surface ◽  
Anterior Border ◽  
Maximum Width ◽  
Strongly Convex ◽  
Basal Half

While on a short visit in northern Maine during the summer of 1946, I collected a new and interesting ant of the Microgyna group of the genus Formica. The description follows below:Formica dirksi sp. nov.Deälate queen, total length 5.1 mm. Head, maximum width through eyes 1.2 mm., at base of mandibles 0.78 mm., length to anterior border of clypeus 1.3 mm. Thorax, Weber's (1938: 155, footnote) measurement 2.1 mm. General characters of the Microgyna group. Mandibles 7-toothed. Clypeus evenly rounded in front, with uneven surface and carina just barely distinguishable as a line anteriorly, but becoming a low blunt ridge through the mid-region and disappearing posteriorly. Head, excluding mandibles and eyes, somewhat longer than broad; narrower in front than in behind, with posterior corners evenly rounded, posterior border and sides slightly convex. Antennae of medium size, scape slightly stouter apically than basally, bent slightly and gradually in basal half, joints 2 and 3 of funiculus distinctly longer than broad; the apical joints only slightly longer than broad. Frontal area distinct, subtriangular, and about twice as broad at base as high. Frontal carinae diverging posteriorly, about as long as width of frontal area. Eyes black, more or less oval, strongly convex, remote from mandibular insertions and close to posterior corners of head. Ocelli medium-sized, round, white and forming an isosceles triangle with a base, which is situated posteriorly, equal to 0.24 mm. Ratio of base to the shorter sides is 10 to 7.

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