摘要:

AbstractHypophysectomy inO. punctatusresults in the atrophy of gonads and low activity of thyroid gland. The pituitary gland does not exert its influence on immature ova, but has decisive control over mature and maturing ova as well as over the germ cells in the testis. Changes in thyroid follicles in the absence of the pituitary gland are reduction in number, flattened epithelial cells, and accumulation of colloid in the follicles.

ISSN:0022-104X    

DOI:10.1002/jez.1401580102

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

年代:1965

数据来源: WILEY

摘要:

AbstractHistological studies, carbon, carmine and vital dye marking ofin ovoand explanted blastoderms have provided evidence for the following: (1) The cellular precursors of all three primary germ layers in the unincubated blastoderm are topographically represented by a disc‐shaped, epithelial‐like and complete uppermost layer; and ring‐shaped, incomplete and congruent middle and lowest layers below the uppermost layer. (2) There is a gradient in cell population density decreasing from posterior to anterior. (3) Centripetal extension of a sheet of lowest and adjacent middle layer cells, primarily from the posterior portion of the ring but also from all points on its circumference, results in closing of the ring and completion of the middle and lowest layers as coherent discs. (4) No movement (invagination or involution) of uppermost, surfaceareasas coherent sheets into either the middle or lowest layers could be demonstrated in any region, including the primitive streak. (5) Embryonic germ layers arisein situby proliferation from the streak. (6) The streak in its morphology and function is more like a blastema than a blastopore. (7) As an elongated growth center, the streak has its origin from the marginal zone ring, itself a circular blastema with multiple streak‐ and embryo body‐forming c

ISSN:0022-104X    

DOI:10.1002/jez.1401580103

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

年代:1965

数据来源: WILEY

摘要:

AbstractDuring recent years techniques have been evolved which permit the development of embryonic mouse cleavage stagesin vitro. These methods are now sufficiently reliable for use in quantitative experiments such as the mapping of concentration‐response surfaces to discover the interaction of effects produced by various components of the medium. In studies on the development of mouse embryosin vitroconducted in our laboratory, a series of specialized biometrical problems has arisen.In the present paper, the theoretical basis for analyzing the responses of two‐cell mouse ovain vitrois discussed. The responses are quantal in nature and are transformed before statistical treatment. The application of the angular and probit transformation to this data is illustrated. In certain cases, allowances must be made for a control portion of embryos failing to develop. The analyses are illustrated by two examples, one concerned with the determination of optimum conditions, and the other with the estimation of the median effective dose of a metabolic inhibi

ISSN:0022-104X    

DOI:10.1002/jez.1401580104

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

年代:1965

数据来源: WILEY

摘要:

AbstractSeveral thousand two‐cell mouse ova were cultivatedin vitro, and the effect on development of changing the osmolarity and hydrogen ion concentration of the medium was examined. Statistical experimental design techniques were employed throughout the experiments in order to make the most efficient use of the material available. The two‐cell ova were cultivated for three days, and the percentage which developed into normal blastocysts was used as a measure of the treatment effect.Changing the osmolarity of the medium had a marked effect on the number of blastocysts developing from two‐cell mouse ova. Blastocysts developed in media with osmolarities ranging between 0.2002 and 0.3542 osmols. The optimum osmolarity for the development of two‐cell mouse ova into blastocysts was 0.2760 osmols.The hydrogen ion concentration of the culture medium also had an effect on the development of two‐cell mouse ova into blastocysts. Although blastocysts developed in media with pH's ranging from 5.87 to 7.78, the optimum pH appeared to be

ISSN:0022-104X    

DOI:10.1002/jez.1401580105

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe effect of various possible energy sources on the developmentin vitroof two‐cell mouse ova into blastocysts was examined. Energy for development of two‐cell mouse ova could be supplied by lacatate, pyruvate, oxaloacetate, or phosphoenolpyruvate. Compounds such as glucose, fructose, ribose, glucose‐6‐phosphate, fructose‐1, 6‐phosphate, acetate, citrate, α‐ketoglutarate, succinate, fumarate, and malate could not provide energy for development of two‐cell mouse ova. The optimum concentrations at pH 7.38 for those compounds which would supply energy was 5.00 × 10−2Mlactate, 3.16 × 10−4Moxaloacetate, and 1.00 × 10−2Mphosphoenolpyruvate.The possibility that interactions existed between the effects of osmolarity, pH, and energy source was examined in several experiments. There was no interaction between the effects of osmolarity and pH or osmolarity and the four possible energy sources. However, there was a singnificant interaction between energy source and pH. The result of this is that an increase in pH of the medium results in an increase in the optimum concentration of the compound supplying ene

ISSN:0022-104X    

DOI:10.1002/jez.1401580106

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

年代:1965

数据来源: WILEY

摘要:

AbstractThere has been considerable discussion as to whether the developing mouse ova requires an exogenous protein supply. A series of experiments were performed to determine the effect of various fixed‐nitrogen sources on the developmentin vitroof two‐cell mouse ova into blastocysts. It was found that two‐cell mouse ova would not develop into blastocysts in medium that did not contain a fixed‐nitrogen source. Crystalline bovine serum albumin (BSA) at 1 mg/ml or, alternatively, the constituent amino acids of BSA could supply this requirement for fixed‐nitrogen. In the presence of single amino acids at 10−3Mor 8 × 10−3M, only an occasional two‐cell ova developed into a blastocyst.Single amino acids were omitted from the medium containing the constituent amino acids of BSA in an attempt to demonstrate an essential amino acid requirement of two‐cell mouse ova. The omission of no single amino acid from the medium, completely prevented the development of some two‐cell ova into blastocysts. The only amino acid whose omission resulted in a significant decrease in development was cystine. In the medium where amino acids were used in place of BSA, a non‐protein polymer was used to replace the physical properties of albumin. The non‐protein polymers which appeared best were Polyvinylpyrrolidone (MW = 150,000), Aca

ISSN:0022-104X    

DOI:10.1002/jez.1401580107

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe annual fat body cycle in the lizardUta stansburianais associated with reproduction. In females fat bodies decline in late winter and early spring when deutoplasm is deposited in the ovarian follicles. Males have a similar fat cycle, but fat bodies are much smaller. Ovariectomy eliminated rapid lipid mobilization from the fat bodies which occurs in sham operated controls. Fat body removal from early estrus females induces high incidence of follicular atresia and retards the rate of yolk deposition. Follicular growth is delayed or inhibited if fat bodies are excised from preestrus animals. The amount of extractable lipid in the pre‐estrus fat body is nearly equivalent to the lipid in a typical egg clutch. The adaptive value of the fat bodies is apparently associated with the formation of the first egg clutch which in accordance with population studies is the most important clutc

ISSN:0022-104X    

DOI:10.1002/jez.1401580108

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

年代:1965

数据来源: WILEY

摘要:

AbstractFor the determination of the fertilizing life of ferret sperm in the female tract, gonadotrophin was intraperitoneally injected to induce ovulation at various times after the deposition of epididymal sperm into the uterine horns. The animals were examined 48 or 60 hours after ovulation injection to assess the proportion of fertilized eggs, although a few of them were allowed to deliver young.Intraperitoneal injection of 50 hypophysectomized R.U. of sheep pituitary extracts or 90 I.U. of Human Chorionic Gonadotrophin invariably induced ovulation in ferrets that were in heat. Ovulation occurred about 24 to 36 hours after the administration of H.C.G. and an average of 14.5 eggs with a range of 8 to 24 eggs per animal was obtained.The average number of sperm in the cauda epididymides and the vasa deferentia of nine males was 219 millions with a range of 24 millions at the end of breeding season to 621 millions at the peak of breeding season.The percentage of total eggs that were fertilized was 73, 40, 24, 15, 3, and 0 when the ovulation injection was given at 0, 36, 72, 84, 96, and 108 hours after sperm deposition respectively. Since ovulation occurred 30 hours after ovulation injection the fertilizing life of ferret sperm in the female tract is therefore no more than 126 hours. The percentage of eggs fertilized was lower following the deposition of epididymal sperm than following mating (73% vs. 98%). There is evidence that the fertility of sperm in the female tract was higher if a large number of sperm was deposited, and that the penetration of sperm into the egg facilitated the denudation of the egg.The majority of the penetrated eggs (54 to 84%) were at the pronuclear stage 48 hours after insemination and ovulation injection (i.e., about 18 hours after ovulation), at 60 hours (30 hours after ovulation) the majority of them were either at pronuclear stage (26–100%) or at the 2‐cell stage (46–57%), and at 70 hours (40 hours after ovulation) most of them were at the 4–6 cell stage. The morphology of fertilization in the ferret and the time sequence after sperm penetration were de

ISSN:0022-104X    

DOI:10.1002/jez.1401580109

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

年代:1965

数据来源: WILEY

摘要:

AbstractRelationships between neoplasia and regeneration were studied in the regenerative processes following 21 amputations through or near 8 spontaneous melanotic formations in the tails of axolotls. It was found that spontaneous melanoma can grow in the presence of regeneration, but that melanotic ingrowth into a regenerate tends to be limited to temporary “symbiotic” participation of the melanotic tissue in the development of the regenerate. It was also found that regeneration is almost always essentially normal in the presence of a spontaneous melanoma, even when the regenerate grows from the tumor itself or from a previous regenerate that is black with melanotic cells.Melanotic cells are presumably derived from normal pigment cells, and some investigators have suggested that neoplastic cells under the influence of regenerative processes may occasionally be transformed back into normal cells. The present study has provided no evidence that such a transformation ever occurs. Instead, the regenerative processes seem only to limit the neoplastic activity of melanotic cells that participate in regenerative growth. In fact, when regeneration is abnormal, melanotic cells may behave much as they do in the absence of regenerat

ISSN:0022-104X    

DOI:10.1002/jez.1401580110

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

年代:1965

数据来源: WILEY

摘要:

AbstractIn four species of caddis‐worms,‐Ptilostomis semifasciata(Say),Platycentropus radiatus(Say),Limnephilus indivisusWalker, andPycnopsyche guttifer(Walker), —removal of the anal hooks and the posterior hair sensilla significantly prolonged case‐building activity with a resulting increase in case production. The extensive building was of the rough provisional type, which is normally completed within a few hours. There were differences among the species with regard to the amount of excessive building and the relative importance of the hairs.Transection of the ventral nerve cord appeared to block the extensive building that normally followed hook removal.It is proposed that the stimulus for building is an endogenous process which causes excitatory impulses to be emitted from the several ganglia. The impulses go forward to the integrative areas controlling the animal's building apparatus and stimulate building. The emission of impulses from the ganglia is inhibited by sensory input from contact with t

ISSN:0022-104X    

DOI:10.1002/jez.1401580111

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

年代:1965

数据来源: WILEY