A basic rhythmicity in the mitotic rate of urodele epidermis and the difference in mitotic rate between larvae reared in the laboratory and in a pond

Scheving, Lawrence E.; Chiakulas, John J.; Abzug, Hillyard I.

doi:10.1002/jcp.1030540112

Cited by 9 publications

(1 citation statement)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering the rare mitoses observed in LC of urodeles and our counting, we think that numbers of mitoses are too small to account for the formation of new LC and replacement of old LC unless LC follow a hitherto unexplored circadian rhythm. Using 3 H-thymidine, such rhythms have been demonstrated in various urodele tissues including the larval epidermis of Ambystoma tigrinum and Taricha torosa (scheving et al, 1959;scheving & chiakuLas, 1965;ChiakuLas & scheving, 1966) and the adult epidermis of Notophthalmus viridescens (hoFFmann & denT, 1977) showing a bimodal pattern of mitotic rates. In one of the studies authors also counted mitoses in whole mount preparations, but did not differentiate between keratinocytes and LC in the larval epidermis (scheving & chiakuLas, 1965).…”

Section: Growth and Changes Of Proportions Of Larvaementioning

confidence: 99%

Number and distribution of Leydig cells (LC) in the epidermis of the growing axolotl, Ambystoma mexicanum (Amphibia: Urodela)

Gerling¹,

D’Haese²,

Greven

2012

View full text Add to dashboard Cite

The epidermal Leydig cells (LC) of larval and paedomorphic Urodela (= Caudata) are highly specialized cells, which are characterized by a complex peripheral cytoskeleton (Langerhans’ net) and numerous inclusions usually named secretory granules. We studied number, distribution and development of these cells in larvae up to 100 days after hatching and in some adults of the paedomorphic axolotl (Ambystoma mexicanum). With the exception of a short period after hatching, relation between age and total length of larvae was linear. The tail grew positively, the width of the head negatively allometric. Keeping larvae in groups resulted in a somewhat slower growth, in deviations from a strict linearity of some morphological parameters, and in a delayed increase of the number of LC, which is interpreted as crowding effect. LC could be identified already before hatching and developed first in the head, then in the trunk, and finally in the tail. Number of LC increased highly disproportionally during larval growth. Within 6 months, LC differentiated from relatively small cells (20 × 10 μm) with a vacuolated appearance to large round cells (diameter ca. 65 μm) with distinct and stainable granules and a prominent Langerhans’ net forming several layers within the epidermis. LC neither rested directly upon the basal lamella nor reached the epidermal surface. They showed a moderate mitotic activity in all age groups examined. Number of mitoses appeared too small to explain the high number of LC in the epidermis and to guarantee continuous replacement. Mature, most superficially located LC appear to be shed.

show abstract

Section: Growth and Changes Of Proportions Of Larvaementioning

confidence: 99%

Number and distribution of Leydig cells (LC) in the epidermis of the growing axolotl, Ambystoma mexicanum (Amphibia: Urodela)

Gerling¹,

D’Haese²,

Greven

2012

View full text Add to dashboard Cite

show abstract

Effect of hypophysectomy on the 24‐hour mitotic rhythm of corneal epithelium in urodele larvae

Scheving

Chiakulas

1962

J. Exp. Zool.

View full text Add to dashboard Cite

It is a generally recognized fact that the mitotic rates of mitotically labile tissues of many plants and animals indicate a definite daily cycle or periodicity. However, the basic factors underlying or affecting this cyclic phenomenon of mitotic rates are still being investigated. In animals, the endocrine organs have been suspected as playing a role in controlling or affecting the various biological rhythms observed in the organism, whether these rhythms be manifested in mitotic rates of tissues, body temperatures, activity, number of circula,ting blood cells, etc. The pituitary gland and suprarenals have been the subjects of particular interest and investigation. Zander et al. ('54) have reported on the effects of hypophysectomy on the rhythmic character of mitotic activity in the rat retromolar mucosal epithelium; Ferguson et al. ('57) have explored the role of the pituitary and hypophysectomy in the cyclic nature of rectal temperature in mice. Halberg et al. ('59) and Halberg ('60), reviewing the work done on the effects of hypophysectomy on biological rhythms conclude that as a result of hypophysectomy, mitotic rhythms are altered only, but not obliterated. Instead of the pituitary, Halberg implicates the adrenal gland as the dominant pacemaker of mitotic rhythms and a number of other circadian rhythms.The presence of a definite rhythm over a 24-hour period in the rate of cell division in the epidermis and gastric mucosal epithelium of urodele larvae has been established (Scheving, Chiakulas and Abzug, '59; Chiakulas and Scheving, '61). As will be reported in this paper, a rhythm over a 24-hour period also exists in the mitotic rate of larval corneal epithelium. Since hypophysectomy in urodele larvae is a relatively simple procedure, the effects of hypophysectomy on this cyclic nature of the mitotic rate in corneal epithelium was investigated and will be discussed. Adrenalectomy was not feasible because of the diffuse, scattered nature of the adrenal tissue in urodele larvae. MATERIALS AND METHODSAmblystoma maculatum larvae, 20-25 mm in length, were used in this study.2 The larvae were reared in the laboratory from egg stages and were maintained under a regimen consisting of 12 hours of light alternating with 12 hours of darkness and a constant temperature of 22°C. The animals were kept in filtered tap water and were fed on a diet of enchytraeid worms.Hypophysectomy was accomplished in the following manner: Animals were anesthetized in MS-222 and strapped down individually in an operating dish. The mouth was pried open by means of a blunt forceps. Fine jeweler's forceps were used to penetrate the oral epithelium and chondrocranium of the roof of the mouth in the immediate region of the pituitary gland which was visible through these tissues. The forceps were then inserted around the base of the pituitary and the gland was gently removed.Complete and persistent blanching of the epidermis due to the contraction of the melanophores in the absence of the melanophore expanding hormone of the pituitary, was t...

show abstract

Mitotic activity in the hemopoietic cortical zone of the liver of urodele larvae

Chiakulas

Scheving

1964

Journal of Morphology

View full text Add to dashboard Cite

A basic rhythmicity in the mitotic rate of urodele epidermis and the difference in mitotic rate between larvae reared in the laboratory and in a pond

Cited by 9 publications

References 16 publications

Number and distribution of Leydig cells (LC) in the epidermis of the growing axolotl, Ambystoma mexicanum (Amphibia: Urodela)

Number and distribution of Leydig cells (LC) in the epidermis of the growing axolotl, Ambystoma mexicanum (Amphibia: Urodela)

Effect of hypophysectomy on the 24‐hour mitotic rhythm of corneal epithelium in urodele larvae

Mitotic activity in the hemopoietic cortical zone of the liver of urodele larvae

Contact Info

Product

Resources

About