scholarly journals Hedgehog-dependent proliferation drives modular growth during morphogenesis of a dermal bone

Development ◽  
2012 ◽  
Vol 139 (13) ◽  
pp. 2371-2380 ◽  
Author(s):  
T. R. Huycke ◽  
B. F. Eames ◽  
C. B. Kimmel
Keyword(s):  
Dermal Bone

A Histological Study of the Development of the Scales of the Largemouth Black Bass (Micropterus salmoides)

1953 ◽  
Vol s3-94 (25) ◽  
pp. 71-82
Author(s):  
MARY ALICE DIETRICH
Keyword(s):  
Micropterus Salmoides ◽  
Histological Study ◽  
Age Determination ◽  
Wide Band ◽  
Careful Study ◽  
Dark Line ◽  
Slowing Down ◽  
Dermal Bone ◽  
Black Bass ◽  
Fibroblastic Cells

1. The scale method of age determination in largemouth black bass, Micropterus salmoides, is valid at least up to and probably including the third year of the fish's life. A more careful study of older fish might reveal that it was valid beyond that point. 2. The annulus in a largemouth black bass is formed by a brief but gradual slowing down of growth and then its quick resumption. The annulus appears as a wide band on the anterior edge of the scale, and as a dark line (circulus) cutting across some inner dark lines (also circuli) on the lateral edges. 3. The scale is mesodermal in origin, and lies in a pocket surrounded by dermal tissue, which in turn is covered externally by a thin layer of epidermis. 4. The bony layer is formed by osteoblastic cells on its outer surface in a manner similar to the formation of dermal bone. Excess bony material is accumulated in ridges or circuli. 5. The fibrillary plate is formed by the fibroblastic cells on its inner surface.

Hoxa-2 restricts the chondrogenic domain and inhibits bone formation during development of the branchial area

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2587-2597 ◽  
Author(s):  
B. Kanzler ◽  
S.J. Kuschert ◽  
Y.H. Liu ◽  
M. Mallo
Keyword(s):  
Bone Formation ◽  
Branchial Arch ◽  
Intramembranous Ossification ◽  
Expression Domain ◽  
Sox9 Expression ◽  
Molecular Analyses ◽  
Early Stages ◽  
Branchial Arches ◽  
Skeletal Formation ◽  
Dermal Bone

In Hoxa-2(−/−)embryos, the normal skeletal elements of the second branchial arch are replaced by a duplicated set of first arch elements. We show here that Hoxa-2 directs proper skeletal formation in the second arch by preventing chondrogenesis and intramembranous ossification. In normal embryos, Hoxa-2 is expressed throughout the second arch mesenchyme, but is excluded from the chondrogenic condensations. In the absence of Hoxa-2, chondrogenesis is activated ectopically within the rostral Hoxa-2 expression domain to form the mutant set of cartilages. In Hoxa-2(−/−)embryos the Sox9 expression domain is shifted into the normal Hoxa-2 domain. Misexpression of Sox9 in this area produces a phenotype resembling that of the Hoxa-2 mutants. These results indicate that Hoxa-2 acts at early stages of the chondrogenic pathway, upstream of Sox9 induction. We also show that Hoxa-2 inhibits dermal bone formation when misexpressed in its precursors. Furthermore, molecular analyses indicate that Cbfa1 is upregulated in the second branchial arches of Hoxa-2 mutant embryos suggesting that prevention of Cbfa1 induction might mediate Hoxa-2 inhibition of dermal bone formation during normal second arch development. The implications of these results on the patterning of the branchial area are discussed.

scholarly journals Dermal bone in early tetrapods: a palaeophysiological hypothesis of adaptation for terrestrial acidosis

2012 ◽  
Vol 279 (1740) ◽  
pp. 3035-3040 ◽  
Author(s):  
Christine M. Janis ◽  
Kelly Devlin ◽  
Daniel E. Warren ◽  
Florian Witzmann
Keyword(s):  
Carbon Dioxide ◽  
Lung Ventilation ◽  
Ventilation Mode ◽  
Acid Base Balance ◽  
Dermal Bone ◽  
Base Balance ◽  
Lactate Acidosis ◽  
Early Tetrapods ◽  
Calcified Tissues ◽  
Dermal Bones

The dermal bone sculpture of early, basal tetrapods of the Permo-Carboniferous is unlike the bone surface of any living vertebrate, and its function has long been obscure. Drawing from physiological studies of extant tetrapods, where dermal bone or other calcified tissues aid in regulating acid–base balance relating to hypercapnia (excess blood carbon dioxide) and/or lactate acidosis, we propose a similar function for these sculptured dermal bones in early tetrapods. Unlike the condition in modern reptiles, which experience hypercapnia when submerged in water, these animals would have experienced hypercapnia on land, owing to likely inefficient means of eliminating carbon dioxide. The different patterns of dermal bone sculpture in these tetrapods largely correlates with levels of terrestriality: sculpture is reduced or lost in stem amniotes that likely had the more efficient lung ventilation mode of costal aspiration, and in small-sized stem amphibians that would have been able to use the skin for gas exchange.

scholarly journals Origins of bone repair in the armour of fossil fish: response to a deep wound by cells depositing dentine instead of dermal bone

2013 ◽  
Vol 9 (5) ◽  
pp. 20130144 ◽  
Author(s):  
Zerina Johanson ◽  
Moya Smith ◽  
Anton Kearsley ◽  
Peter Pilecki ◽  
Elga Mark-Kurik ◽  
...  
Keyword(s):  
Wound Repair ◽  
Bone Repair ◽  
Vascular Tissue ◽  
Wound Response ◽  
Deep Wound ◽  
Evolutionarily Conserved ◽  
Fossil Fish ◽  
Dermal Bone ◽  
Mammalian Teeth ◽  
Fish Response

The outer armour of fossil jawless fishes (Heterostraci) is, predominantly, a bone with a superficial ornament of dentine tubercles surrounded by pores leading to flask-shaped crypts (ampullae). However, despite the extensive bone present in these early dermal skeletons, damage was repaired almost exclusively with dentine. Consolidation of bone, by dentine invading and filling the vascular spaces, was previously recognized in Psammolepis and other heterostracans but was associated with ageing and dermal shield wear (reparative). Here, we describe wound repair by deposition of dentine directly onto a bony scaffold of fragmented bone. An extensive wound response occurred from massive deposition of dentine (reactionary), traced from tubercle pulp cavities and surrounding ampullae. These structures may provide the cells to make reparative and reactionary dentine, as in mammalian teeth today in response to stimuli (functional wear or damage). We suggest in Psammolepis , repair involved mobilization of these cells in response to a local stimulatory mechanism, for example, predator damage. By comparison, almost no new bone is detected in repair of the Psammolepis shield. Dentine infilling bone vascular tissue spaces of both abraded dentine and wounded bone suggests that recruitment of this process has been evolutionarily conserved over 380 Myr and precedes osteogenic skeletal repair.

scholarly journals Dioxin disrupts cranial cartilage and dermal bone development in zebrafish larvae

2015 ◽  
Vol 164 ◽  
pp. 52-60 ◽  
Author(s):  
Felipe R. Burns ◽  
Richard E. Peterson ◽  
Warren Heideman
Keyword(s):  
Bone Development ◽  
Zebrafish Larvae ◽  
Dermal Bone

Involvement of the sonic hedgehog, patched 1 and bmp2 genes in patterning of the zebrafish dermal fin rays

Development ◽  
1998 ◽  
Vol 125 (21) ◽  
pp. 4175-4184 ◽  
Author(s):  
L. Laforest ◽  
C.W. Brown ◽  
G. Poleo ◽  
J. Geraudie ◽  
M. Tada ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Sonic Hedgehog ◽  
Bone Matrix ◽  
Basal Layer ◽  
Pectoral Fin ◽  
Expression Domain ◽  
Fin Regeneration ◽  
Fin Rays ◽  
Dermal Bone ◽  
Fish Fins

The signaling molecule encoded by Sonic hedgehog (shh) participates in the patterning of several embryonic structures including limbs. During early fin development in zebrafish, a subset of cells in the posterior margin of pectoral fin buds express shh. We have shown that regulation of shh in pectoral fin buds is consistent with a role in mediating the activity of a structure analogous to the zone of polarizing activity (ZPA) (Akimenko and Ekker (1995) Dev. Biol. 170, 243–247). During growth of the bony rays of both paired and unpaired fins, and during fin regeneration, there does not seem to be a region equivalent to the ZPA and one would predict that shh would play a different role, if any, during these processes specific to fish fins. We have examined the expression of shh in the developing fins of 4-week old larvae and in regenerating fins of adults. A subset of cells in the basal layer of the epidermis in close proximity to the newly formed dermal bone structures of the fin rays, the lepidotrichia, express shh, and ptc1 which is thought to encode the receptor of the SHH signal. The expression domain of ptc1 is broader than that of shh and adjacent blastemal cells releasing the dermal bone matrix also express ptc1. Further observations indicate that the bmp2 gene, in addition to being expressed in the same cells of the basal layer of the epidermis as shh, is also expressed in a subset of the ptc1-expressing cells of the blastema. Amputations of caudal fins immediately after the first branching point of the lepidotrichia, and global administration of all-trans-retinoic acid, two procedures known to cause fusion of adjacent rays, result in a transient decrease in the expression of shh, ptc1 and bmp2. The effects of retinoic acid on shh expression occur within minutes after the onset of treatment suggesting direct regulation of shh by retinoic acid. These observations suggest a role for shh, ptc1 and bmp2 in patterning of the dermoskeleton of developing and regenerating teleost fins.

The pelvic girdle and hind limb ofCrassigyrinus scoticus(Lydekker) from the Scottish Carboniferous and the origin of the tetrapod pelvic skeleton

1990 ◽  
Vol 81 (1) ◽  
pp. 31-44 ◽  
Author(s):  
A. L. Panchen ◽  
T. R. Smithson
Keyword(s):  
Vertebral Column ◽  
Hind Limb ◽  
Pelvic Girdle ◽  
Lower Carboniferous ◽  
Upper Carboniferous ◽  
Anatomy And Physiology ◽  
Skull Roof ◽  
Dermal Bone ◽  
Skeletal Reconstruction ◽  
Pelvic Fin

ABSTRACTOur knowledge of the primitive and aberrant early tetrapodCrassigyrinus scoticuswas based on a partial skull roof and mandibles from the Lower Carboniferous of Gilmerton, Edinburgh, plus a skeleton lacking the hind limb and tail from the Namurian, basal Upper Carboniferous, of Cowdenbeath, Fife. New specimens from Cowdenbeath include the pelvic girdle, presacral and sacral rib and most of the hind limb. The ilium of the girdle had a firm articulation with the vertebral column via the sacral rib. The ischium, separated from the ilium by cartilage, was, like that found with the Cowdenbeath skeleton, ornamented as though a dermal bone. No pubis is preserved. The femur lacks an adductor crest, but has a strongly developed internal trochanter. Tibia and fibula are short stout bones, but axial torsion is present in the fibula rather than the tibia. This, and the structure of the femur, suggests a swimming rather than a walking limb. Probable metatarsals and phalanges are recorded. A skeletal reconstruction and a life restoration ofCrassigyrinusare presented in the light of its reconstructed anatomy and physiology.The ornamentation of the ischium ofCrassigyrinus, and that of the colosteidGreererpeton, suggests that the bone may be at least in part dermal. Its homology wth the pelvic fin basal scute of osteolepiform fishes is proposed and the homologies of pectoral and pelvic fins, and thus limbs, discussed.

Morphogenesis of shell and scutes in the turtle Emydura macquarii

1999 ◽  
Vol 47 (3) ◽  
pp. 245 ◽  
Author(s):  
Lorenzo Alibardi ◽  
Michael B. Thompson
Keyword(s):  
Light And Electron Microscopy ◽  
Body Cavity ◽  
The Body ◽  
Embryonic Stage ◽  
Small Areas ◽  
Hind Limbs ◽  
Dermal Bone ◽  
Superficial Dermis ◽  
Dermal Bones ◽  
Extracellular Fibrils

Formation of the scutes and dermis of the embryonic shell of the turtle Emydura macquarii was studied using light and electron microscopy. Shell morphogenesis begins at embryonic stage 15 and the shape of the shell is mostly completed by embryonic stage 19. The carapace anlagen arises as a thickening of the skin in the dorsal part of the mid-trunk region between the anterior and posterior limbs. This thickening extends ventro-laterally to form ridges at the margins of the carapace. Each ridge forms as a thick epidermal placode over a condensation of mesenchymal cells. The epidermis behind the advancing margins of the carapace is cuboidal or columnar but does not form placodes. The margins of the carapace expand rapidly in all directions. The plastron anlagen is derived from epidermal cells localised in the latero-ventral regions between the fore- and hind-limbs. Plastron placodes are present laterally, while the mid-ventral and central epidermis remains cuboidal or columnar but does not form placodes at embryonic stage 16. The plastron thickening rapidly moves from a latero-ventral position to a flat ventral position between embryonic stages 16 and 19. Dermal–epidermal anchoring complexes occur throughout placodes of both the carapace and plastron, but are rare in non-placode areas. The accumulation of a dense mesenchyme beneath the shell epidermis forms a dermal cushion that surrounds the body cavity. The superficial dermis close to the epidermis is made of mesenchymal fibroblasts at embryonic stage 19, although the inner-most areas contain bipolar fibroblasts and extracellular fibrils. Scutes with serrations at their borders form as invaginations of the epidermis into the dermis in the mid-dorsal areas of the embryo at embryonic stages 18–19. Dermal–epidermal anchoring complexes are located around the infoldings that form the scutes of the hinge region. The epidermis of the shell has 2–3 suprabasal cells at embryonic stages 19–22, and lacks keratinisation before embryonic stage 22 when it has 4–6 suprabasal layers with 2–3 external layers made of flat cells. The dermis thickens and has numerous collagen fibrils after embryonic stage 19. The formation of dermal bones begins at embryonic stage 18–19 in the plastron. Only small areas of the carapace near to the bridge have begun to form dermal bone at embryonic stage 19. Calcification begins at embryonic stage 19, but is still incomplete at embryonic stages 24–25.

Studies of the rapid effects of parathyroid hormone and prostaglandins on 45Ca uptake into chick and rat bone in vivo

1987 ◽  
Vol 115 (3) ◽  
pp. 369-377 ◽  
Author(s):  
C. G. Dacke ◽  
A. J. Shaw
Keyword(s):  
Parathyroid Hormone ◽  
Prostaglandin E ◽  
Parallel Study ◽  
Endochondral Bone ◽  
Parathyroid Hormones ◽  
Ca Uptake ◽  
Dermal Bone ◽  
Net Uptake ◽  
Microwave Fixation

ABSTRACT The rapid effects of parathyroid hormones and a variety of prostaglandins on net uptake of 45Ca into the skeleton have been investigated in chicks and, in a limited parallel study, in immature rats. Intravenous injection of bovine (b) parathyroid hormone(1–34) bPTH(1–34)) or 16,16-dimethyl prostaglandin E2 (16,16-dimethyl PGE2) in a 45Ca-labelled vehicle, combined with subsequent microwave fixation of tissue isotope levels, resulted in rapid (3–15 min) net inhibition of 45Ca uptake into endochondral bone (femur) in chicks (12 days old) and rats (4 weeks old). Use of 125I-labelled albumin and [14C]mannitol indicated that these responses were not a reflection of gross changes in tissue vascular or extracellular space. In rats, bPTH(1–84) also caused significant net inhibition of 45Ca uptake into femur at 10 min. Both bPTH(1–34) and 16,16-dimethyl PGE2 produced generally smaller decreases in 45Ca uptake into chick dermal bone (calvarium) at 3–15 min. In rat calvarium, however, these agents stimulated net uptake of 45Ca at these times. When microwave fixation was omitted, inhibitory responses were reduced or disappeared, while the stimulatory response in rat calvarium was enhanced. Responses to natural prostaglandins (PGE1, PGE2, PGF2α and PGI2) in chicks at 3 min were similar but less marked than those to 16,16-dimethyl PGE2; 45Ca uptake into femur and, to a lesser extent in calvarium, being inhibited. In rats, PGE1, PGE2 and PGF2α showed a tendency to decrease 45Ca uptake into femur while PGE1 and PGE2 both increased 45Ca uptake into calvarium. J. Endocr. (1987) 115, 369–377

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