摘要:

AbstractTreatment of isolated tadpole (Rana catesbeiana) gastrocnemius muscles with either insulin or thyroxine, in a rich nutritive medium, results in an approximate doubling of incorporation of3H‐leucine into perchloric acid‐precipitable material. We have not observed parallel increases in the amount of acid‐soluble label appearing in hormone‐treated muscles. Various combinations of insulin and/or thyroxine with growth hormone give responses similar to those occurring with insulin or thyroxine alone. The greatest rates of incorporation, relative to control muscles receiving no hormone treatment, were observed in muscles exposed briefly to thyroxine, insulin and growth hormone simultaneously. The interaction of prolactin with thyroxine in this quasi‐adult system remains

ISSN:0022-104X    

DOI:10.1002/jez.1401710402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractA new technique for transplanting imaginal disks of the housefly is described. When prepupal disks are transplanted superficially (surface transplantation) just beneath the puparium in early prepupal hosts, they evaginate synchronously with the host's organs and differentiate normally like the disks developingin situ. Histological evidence indicates that cells from the peripheral region of the disks migrate and join the epidermis of the host. This facilitates continuation of morphogenetic events culminating in eversion of the transplant. The significance of the cellular contact with epidermal cells of the host is discussed.A well developed nerve from the transplanted leg joins the thoraco‐abdominal ganglion of the host. Flexion of the terminal leg segments indicates the presence of motor fibers innervating muscles in the leg.Disks from late third instar larvae and young prepupae evaginate whereas disks from younger third instar larvae fail to evaginate when surface transplanted. Disks, from all types of donors, cultured in adult abdomens fail to evaginate when retransplanted in prepupae. These and other results suggest that hormones may induce or inhibit morphogenetic cell movement in imaginal disk

ISSN:0022-104X    

DOI:10.1002/jez.1401710403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractAs in other decapod crustacea, the muscles of the hermit crab abdomen are divided into a central mass of muscle, active during the escape response, and a superficial layer of muscles which is responsible for the normal postural movements of the abdomen. The ventral superficial muscles consist of three layers, a mesial layer of longitudinal fibers, and two distal layers of circular muscle. The longitudinal muscles are thicker on the right side and are divided into three longitudinal strips each innervated by a single excitor motoneuron. Six motor axons innervate the ventral superficial muscles on each side — those on the right are larger than those on the left. Also occurring in the third ganglionic root is a group of fine axons believed to be branches of the motoneurons. There does not appear to be any relationship between the size of the motoneuron and the amount of muscle innervate

ISSN:0022-104X    

DOI:10.1002/jez.1401710404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe five excitors and one inhibitor which innervate each side of the ventral superficial muscles of the hermit crab are described. The longitudinal layer receives three excitors, one of which phasically activates a lateral strip of muscle, the second tonically drives a ventromedial strip and the third innervates a strip between the other two. The inhibitor innervates the last two regions of longitudinal muscle as well as the circular muscle. Two excitors, a phasic and a tonic fiber innervates adjacent longitudinal regions of the circular muscles, but less is known of their reflex behavior. In all cases, the tonic frequency of units on the right was less than their homologues on the left, but this asymmetry was reversed during a reflex discharge. Isolation of the ganglion increased the asymmetry of spontaneous activity. It is suggested that this asymmetry may not have any functional importance but instead may be related to the different sizes of motoneurons on the two sides.

ISSN:0022-104X    

DOI:10.1002/jez.1401710405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractExperiments with a transparent plastic snail shell indicated that the hermit crab carries the columella in the crook of its bent abdomen. There are three components to the normal curvature of the abdomen in the region of the third segment, a ventroflexion of 30°, a pitch to the right of 10°, and a clockwise rotation of 20° of the whole abdomen about the thoracic‐abdominal junction. The forces and bending moments produced by the ventral superficial muscles were estimated from the sizes of the muscles, their position on the circumference of the abdomen, the amplitudes of the EJPs of the motoneurons, and their firing frequency. These calculations are in reasonable agreement with the behavioral measurem

ISSN:0022-104X    

DOI:10.1002/jez.1401710406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe pattern of DNA replication during the initial stages of Wolffian lens regeneration has been examined by an autoradiographic study of tritiated thymidine uptake in zero to five‐day regenerates (Triturus viridescens). Scanning of complete sets of serial sections for each iris revealed the absence of labeled cells in normal, one‐, and two‐day iris epithelia, and a very infrequent occurrence of labeled iris epithelial cells in some three‐day regenerates. After this stage, cell labeling is seen in all iris epithelia. Cell labeling frequency increases markedly by four days, and is at a very high level in five‐day regenerates.Further data indicate that labeling begins in the dorsal sector of the iris epithelium. By five days after lens removal, however, it reaches similar levels in dorsal, lateral, and ventral sectors. Thus, DNA replication is induced throughout the iris epithelium after lens removal, even though the lateral and ventral sectors of the iris epithelium do not participate in actual lens formation.Comparison between the outer and inner laminae of the iris epithelium shows that during all stages studied the great majority of labeled cells are in the inn

ISSN:0022-104X    

DOI:10.1002/jez.1401710407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe neurotrophic influence on the morphological maintenance of the lateral‐line sensory organs has been studied in the adult newt,Triturus viridescens, under various conditions of denervation. Results show little if any atrophic and degenerative changes during two months following resection of the lateral‐line nerve or the incident spinal nerves. However, if both are destroyed, thus rendering the total environs of the organs nerveless, atrophy and degeneration are advanced within a two‐month period and, indeed, are evident within three weeks. The results favor the idea of neurotrophic control of the lateral‐line sensory organs in amphibians. The results are discussed against the background of past controversies and speculations on the neurotrophic phenomenon. Various control experiments including heterotopic transplantation of the sensory organs are also r

ISSN:0022-104X    

DOI:10.1002/jez.1401710408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effect of blinding on reproductive and pelage cycles in ferrets held outdoors under natural environmental conditions was investigated from October, 1966, to March, 1969. Blind female and intact male and female ferrets underwent the normal seasonal changes during this period. They became reproductively active and underwent the spring molt in March and April and became reproductively quiescent, molted and grew the dense winter pelage in September and October. Blind male ferrets exhibited a prolonged reproductive period which began in March and April, 1967, and extended through December. An incomplete pelage change and partial testicular regression occurred in most blind males in January and February, 1968. The same sequence of reproductive and coat changes was observed the following year. Blind and intact female ferrets mated to blind males bore normal litters.

ISSN:0022-104X    

DOI:10.1002/jez.1401710409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractTen of 15 hypophysectomized newts with pituitary xenografts from larval axolotls,Ambystoma mexicanum, survived for over 140 days, regenerated amputated limbs and underwent occasional molts. Newts from which the larval pituitary graft was removed underwent typical hypophysectomy symptoms: sluggishness, lack of molting and death within 30 days. The results suggest that the pituitary of the larval axolotl, when implanted into the adult newt, secretes the hormones which are essential for survival and limb regeneration of the adult newt. Furthermore, pituitary xenografts to newts survive as long as pituitary homografts.

ISSN:0022-104X    

DOI:10.1002/jez.1401710410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractFerret eggs recovered from oviducts and uteri at various times after insemination were transferred to the uteri of recipient animals on various days of pseudopregnancy. Fifteen per cent of newly fertilized two day eggs recovered from oviducts were implanted when transferred to uteri of two‐day pseudopregnant ferrets but only 5% developed to fetuses. Synchronous transfer of four‐, six‐, seven‐ and eight‐day eggs to uteri of four‐, six‐, seven‐ and eight‐day pseudopregnant ferrets resulted in 44‐62% of implantations, but only 21–41% of eggs developed to fetuses. Twenty‐one‐fifty‐seven percent of eggs were implanted, and 8–29% of eggs developed to fetuses when eggs were transferred to uteri of ferrets that had ovulated two days later. When transferred to uteri of ferrets that had ovulated two days earlier none developed to fetuses although 33–50% of transferred eggs implanted. No fetal development was observed when six‐day eggs were transferred to estrous ferrets treated with various progestins, but a f

ISSN:0022-104X    

DOI:10.1002/jez.1401710411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY