摘要:

AbstractHigh concentrations of sulfolipids (four fractions having different hexose/sulfate ratio), intense enzyme activity (ATPase, oxoreductases) and evidence of mucines (staining with PAS and Alcian blue) in intercellular spaces were found in the lachrymal glands ofCaretta carettaandMalaclemys terrapinadapted to sea water. In addition, the supranuclear region of the gland cells inMalaclemys terrapinis filled with mucin granules.These biochemical and histochemical observations indicate that these glands have a function in salt secretion in both species and are also consistent with a function of mucous secretion exclusively inMalaclemys terrapin.Limited signs of hypotrophy are not accompanied by changes in concentrations of sulfolipids inMalaclemys terrapinadapted to fresh water; only the reactions for enzyme activities are less intense. The mucous secretion is not affected, whereas, in correlation with changes in salt secretion, the change in ATPase activity is most conspicuous.The correlations between the different components of the gland and salt secretion are compared with salt glands of birds and elasmobranchs.

ISSN:0022-104X    

DOI:10.1002/jez.1401950202

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe properties of acid phosphatase from the cement gland ofXenopus laevisembryos were investigated both biochemically and electrophoretically. The studies were made on excised glands at a preregressing stage (stage 35/36, Nieuwkoop and Faber staging series) and a regressing stage (stage 45). The total activity (amount of p‐nitrophenol released/hr/gland) of acid phosphatase increased 1.7‐fold while the specific activity (amount of p‐nitrophenol released/hr/μg protein) increased 2.8‐fold from stage 35/36 to stage 45. There was some indication of a changing pH pattern during regression. Acid phosphatase activity showed a slight peak at pH 4.5 at stage 35/36 but a sharp optimal peak at pH 5.0 at stage 45. Also, there was increased phosphatase activity in both isotonic and hypotonic homogenates, in the absence of Triton X‐100, during gland cell regression. Electrophoretic separation of acid phosphatases from cement gland homogenates resolved two isozymes at stage 35/36, and two more forms appeared at stage 45. Both the quantitative and qualitative changes seen during cement gland development suggest a correlation between acid phosphatase activity and gland cell

ISSN:0022-104X    

DOI:10.1002/jez.1401950203

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe rate of active sodium transport as measured by short‐circuit current across the isolated skin of the toad,Scaphiopus couchi, was elevated following vasopressin (0.2 units/ml) or arginine vasotocin (0.1 units/ml) treatment of skins from active animals at all times of the year tested. Skins from dormant animals showed no such elevation at any time of the year. The rate of active sodium transport was elevated following treatment with dibutyryl cyclic AMP (2.5 mM) plus theophylline (10 mM) in all skins tested.The hydraulic conductivity of isolated skins from both active and dormant animals showed no significant change following treatment with vasopressin (0.2 units/ml) or arginine vasotocin (0.1 units/ml) except on the first day following emergence from dormancy in the field. A correlation was, therefore, observed between the occurrence of a hydroosmotic response to antidiuretic hormones and the seasonal exposure ofS. couchito standing water.A small but significant elevation of hydraulic conductivity was observed across the skins of dormant toads following treatment with dibutyryl cyclic AMP (2.5 mM) plus theophylline (10 mM) whereas a substantial elevation was observed with the skins of active animal

ISSN:0022-104X    

DOI:10.1002/jez.1401950204

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

年代:1976

数据来源: WILEY

摘要:

AbstractEmbryos of the Rouen duck were treated on day 11 to 18 with a single injection of estradiol benzoate in the air chamber. After hatching, skin grafts were exchanged between male ducklings that had been treated with estrogenin ovoand control males. The results showed that the skin of male embryos can be permanently feminized to the same extent as untreated female embryos simply by exposing embryonic male skin to female sex hormones during embryogenesis.

ISSN:0022-104X    

DOI:10.1002/jez.1401950205

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

年代:1976

数据来源: WILEY

摘要:

AbstractMouse ova with or without follicular cells (denuded) were treated with wheat germ agglutinin (WGA) in concentrations ranging from 5–500 μg/ml and fertilized in vitro. Ova subjected to concentrations greater than 10 μg/ml WGA were incapable of fertilization in vitro, although sperm were observed adhering to the zona pellucida after treatment in concentrations as high as 500 μg/ml WGA. At concentrations of 50 μg/ml or higher, WGA adversely affected the shape of the vitellus. Of various saccharides employed to block the effects of WGA D‐glucose was the most effective.Injections of 0.03 ml of 100 μg/ml or 500 μg/ml WGA into the ovarian bursa two to three hours before the expected time of ovulation had little or no effect on fertilizatio

ISSN:0022-104X    

DOI:10.1002/jez.1401950206

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

年代:1976

数据来源: WILEY

摘要:

Abstract1Pressures previously measured on the body surface of swimming bluefish were resolved into their backward vectorial components to allow calculation of profile drag. It was 0.18 kg at a speed of 1.8 m/sec. Tangential drag was calculated as if for a thin plate of an area equal to that of the fish. It was 0.08 kg at 1.8 m/sec. Net drag, 0.26 kg, was the sum of profile and tangential drag.2Thrust and drag also were calculated from the changes of acceleration measured during steady swimming, assuming that thrust took place only during the acceleration phase, whereas drag occurred during both acceleration and deceleration. This drag was 0.08 kg at a speed of 1.1 m/sec. It is compatible with the drag of 0.26 at 1.8 m/sec calculated from profile and tangential drag provided drag varies as the square of velocity.3The force required to produce maximal acceleration was measured during a scare. It was calculated to be 6.9 kg at a peak acceleration of 3 g.4The compression strength of the vertebrae was found to be approximately 20 kg per cm2, or roughly three times the force encountered during maximal acceleration. This safety factor of 3 would be reduced when the back was curved, or if opposing groups of muscles were under tension.5The finding that a bluefish can accelerate at 3 g and that the vertebral column is strong enough to withstand this force indicates that the muscles and body structure of a bluefish would be able to withstand the force of gravity if the fish were otherwise equipped for terrestrial life. This fish may have evolved these strengths simultaneously with land animals. It is speculated that other fish may have evolved some degree of strength to overcome inertia and drag during aquatic locomotion, and this evolution may have been a prelude to terrestrial locomotion.

ISSN:0022-104X    

DOI:10.1002/jez.1401950207

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

年代:1976

数据来源: WILEY

摘要:

AbstractSkin rotation grafts were performed inRana pipienstadpoles producing misdirected reflexes in adult frogs. The pattern of innervation fields of dorsal and ventral rami of segmental nerves 3, 4, 5 and 6 were investigated by recording from the severed rami with suction electrodes. Innervation patterns of regenerated fields were influenced by graft borders and adjacent fields. Misdirected reflexes were found for ventral skin on the dorsal side only when innervated by ventral rami in a manner never seen in normal or sham operated animals. This suggested that selective reinnervation has occurred.

ISSN:0022-104X    

DOI:10.1002/jez.1401950208

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

年代:1976

数据来源: WILEY

摘要:

AbstractA congenitally polled red deer stag was captured from a Scottish deer forest and kept in an enclosure for observations. The animal had rudimentary antler pedicles but no antlers, and during five years of study no significant antler development occurred. Amputation of the apex of one antler pedicle in May 1974 when the stag was 12 years of age resulted in the growth of a complete antler on the operated side, and this antler was subsequently cleaned and cast in the normal way and a new antler cycle was initiated.The result illustrates that the primary abnormality in this polled stag lay not in his inability to grow antlers, but in his inability to develop fully formed antler pedicles from which normal antler tissue could differentiate. Traumatizing the rudimentary pedicle had the effect of stimulating growth of antler tissue, and once this was formed the process of cleaning, casting and regrowth occurred spontaneously. The incomplete development of the antler pedicles is considered to be responsible for the absence of antlers in the majority of “hummels” in Scotland, and the etiology of the condition is discus

ISSN:0022-104X    

DOI:10.1002/jez.1401950209

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

年代:1976

数据来源: WILEY

摘要:

AbstractMitotic activity and DNA and RNA precursor incorporation were compared in innervated regenerating limbs and in denervated, nonregenerating limbs on days 8 and 9 post‐amputation. Innervated limbs had well‐developed cone stage blastemas which showed high cellular mitotic indices and H3‐thymidine labeling indices of 0.40–0.50 and H3‐uridine labeling indices of 0.50–0.75.In contrast, denervated limbs showed dedifferentiated cells distally under thickened wound epithelia, but essentially no mitotic activity and no blastema formation. These dedifferentiated cells showed lower levels of H3‐thymidine (0.10 index) and H3‐uridine (0.50) incorporation than regenerating limbs.Labeling indices of wound epithelia ar

ISSN:0022-104X    

DOI:10.1002/jez.1401950210

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe physical parameters controlling the release of gametes inStyela plicatawere studied in laboratory experiments designed to simulate environmental conditions. Gravid animals left in constant light did not spawn until subjected to a minimum dark period followed by a sufficient amount of light. The maximum spawning success, determined by laboratory experiments, was found during the period between September, 1974 and March, 1975. The minimum dark adaption time, derived statistically from the spawning curve, was found to be 8 hours, 30 minutes. Increasing the dark adaption time resulted in decreasing the amount of light necessary to induce spawning. The total time for an entire spawning cycle (i.e., from the beginning of the dark adaption period to gamete release) was found to be approximately 24 hours. Field collection data supported the laboratory observations showing gamete release in the late afternoon, close to sunset. The amount of dark adaption affects the amount of light necessary to induce spawning suggesting a reversible photochemical reaction. Temperature limits for spawning in the laboratory were found to be 11–28

ISSN:0022-104X    

DOI:10.1002/jez.1401950211

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

年代:1976

数据来源: WILEY