摘要:

AbstractThe cycle of the seminiferous epithelium inM. o. ochrogasterwas divided into eight readily recognizable stages based on the morphology of the developing spermatid. The mean relative frequencies of Stages I through VIII were 11.66, 19.25, 20.00, 19.00, 8.42, 6.17, 9.25 and 6.58%, respectively.The duration of one cycle of the seminiferous epithelium in this species, as determined from autoradiographs of thymidine‐H3injected testes was 7.17 days (S.E. ± 0.03). This is the shortest spermatogenic cycle reported for any mammal to date. The approximate durations of the meiotic prophase, meiotic divisions, and spermiogenesis were 8.8, 0.4 and 12.2 days, respectively. The entire process of spermatogenesis was estimated to span approximately 28.68 days.The number of cycles that spermiogenesis spanned in this species was compared to values calculated for other species. Values within groups of related species appear relatively constant, but between groups the values are variab

ISSN:0022-104X    

DOI:10.1002/jez.1401970102

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

年代:1976

数据来源: WILEY

摘要:

Abstract(C57BL/10 × CBA)F1mouse eggs were incubated in vitro with either F1or outbred TO sperm for 15 minutes‐6 hours. Upon removal from the sperm suspensions some eggs were treated with pronase to remove zonae and then cultured, while the remainder were simply cultured to allow a comparison of the fertilization rates in the two groups. Although a brief incubation was sufficient for a high rate of fertilization when the zonae remained intact, results from the zona‐free eggs indicated that penetration, i.e., sperm fusion with the vitellus, had not been achieved in all eggs during the shorter incubations. Results from the latter groups of eggs indicated that a 1 hour incubation with TO sperm and a 2 hour incubation with F1sperm were needed to obtain a mean fertilization rate of 50%. Fertilization was complete within 1.5 hours using TO sperm and 2.5 hours using F1sperm, thus indicating that under similar environmental conditions sperm genotype can significantly affect the rate of penetra

ISSN:0022-104X    

DOI:10.1002/jez.1401970103

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

年代:1976

数据来源: WILEY

摘要:

AbstractAfter autotomy of seven appendages and partial regeneration, crabs (Uca pugilator) were subjected to removal of one, three, or six developing limb buds at different stages of limb growth. Removal of one limb had no effect on the growth of the remaining limb buds or the time of ecdysis, and the limb bud removed was not replaced before ecdysis. Removal of six limb buds early in the regenerative period caused a retardation of growth in the remaining bud until the reamputated buds could be replaced. Ecdysis was postponed in these animals. Removal of six limb buds at a later stage, or removal of three limb buds at any stage, produced a slight delay in growth of the remaining bud(s) which was not always statistically significant. The inhibition of growth in the remaining bud(s) was greatest in those individuals which went on to replace the reamputated buds. Such individuals also exhibited a longer time to ecdysis.No inhibition of growth or delay in ecdysis was produced in small crabs (11–12 mm carapace width) by removal of one, three, or six limb buds. These were generally not replaced.Animals which had six limb buds removed early in regeneration showed a greater inhibition of growht in the remaining limb bud than those which had eyestalks as well as six limb buds removed. This latter group, however, did show a significant retardation. This is considered evidence for the production of limbgrowth inhibiting substances in other sites in addition to the eyestalks.Limb buds which had been injured grew more slowly than contralateral control limbs initially, but the difference diminished as the crabs approached ecdysis. Ecdysis was not delayed by the presence of this one incomplete limb bud. This is consistent with the lack of effect of removal of a single limb bud, seen in the previous experiment

ISSN:0022-104X    

DOI:10.1002/jez.1401970104

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe surface coats of sea urchin eggs and the events of fertilization which take place on these surfaces were examined with the scanning electron microscope (SEM). Gametes ofStrongylocentrotus purpuratusandLytechinus pictuswere considered in detail; eggs of seven other echinoids were examined for comparative purposes. Jelly coats, preserved by varying the pH of fixation, were found to vary in morphology and solubility properties between species. The vitelline layers of the nine echinoids are characterized by arrays of projections which are impressions of cytoplasmic microvilli in the vitelline layer. After sperm bind to the egg surface via the acrosomal process, fine filaments, apparently an egg response to insemination, further connect some sperm heads and tails to the egg. The cortical reactions spread out as a wave from where the fertilizing sperm fused with the egg; separation of the vitelline layer proceeds as a smooth wave front inS. purpuratuseggs and as a series of localized separations inL. pictuseggs. The fertilization membranes ofS. purpuratusandAllocentrotus fragiliszygotes are expanded replicas of their respective vitelline layers, suggesting that fertilization membranes are formed by an unfolding of the vitelline layer.

ISSN:0022-104X    

DOI:10.1002/jez.1401970105

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects of cytochalasin B on oral apparatus morphogenesis and cell division were studied in synchronizedTetrahymena pyriformis, strain WH‐6, syngen 1. Cytochalasin B brought about the rapid arrest of oral apparatus primordium development when added prior to the completion of oral apparatus membranelle differentiation. Cells arrested in development did not divide. When cytochalasin B was added after this transition point, oral apparatus morphogenesis and cell division were completed. The effects of cytochalasin B could be reversed by washing it from the medium. Even though cytochalasin B (at 400 μg/ml) reduced protein synthesis by 30%, the data are consistent with the interpretation that cytochalasin B prevents an assembly process during the membranelle differentiation phase of oral apparatus developme

ISSN:0022-104X    

DOI:10.1002/jez.1401970106

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe binding of tritium‐labelled cytochalasin B by the isolated oral apparatus ofTetrahymena pyriformis, strain WH‐6, syngen 1, was investigated. Equilibrium binding studies revealed approximately 1.4 × 105cytochalasin B binding sites per oral apparatus. A Scatchard plot indicates a single class of binding affinities with an association constant of 105liters/mole. Rapid release of oral apparatus‐bound cytochalasin B occurred when oral apparatuses were washed and resuspended in 1 mM TRIS without cytochalasin B. Because cytochalasin B binding to oral apparatus microtubular protein was not detected, microtubules are probably not the cytochalasin B binding site. The probable nature of the cytochalasin B binding site within oral apparatus is dis

ISSN:0022-104X    

DOI:10.1002/jez.1401970107

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe cellular and subcellular localization of radioactivity by drymount autoradiography was studied at 5, 15 and 30 minutes after intraluminal or at 5, 15 and 60 minutes after subcutaneous administration of (3H) estradiol or (3H) progesterone to rats in which implantation was delayed by ovariectomy on day 3 post‐coitum, followed by treatment with progesterone. After intraluminal instillation of (3H) estradiol or (3H) progesterone, radioactivity was cleared from the uterine lumen at 5 minutes. After intraluminal as well as subcutaneous injection of (3H) estradiol, radioactivity was concentrated at all time intervals in the nuclei of cells of the substantia propria, glands and muscularis, but not in the luminal epithelium. White blood cells and endothelial cells were unlabeled, while perivascular cells showed concentration of radioactivity.After intraluminal instillation of (3H) progesterone, radioactivity was retained in the cytoplasm of the luminal epithelium at 5 and 15 minutes, while no such concentration appeared after subcutaneous injection. No selective nuclear retention was observed in the luminal epithelium, in contrast to the substantia propria and muscularis.The autoradiographic results indicate that progesterone treatment simulating the conditions of early pregnancy, changes the uptake affinity of uterine tissues for (3H) estradiol. The lack of a detectable concentration of estrogen within nuclei of the luminal epithelium does not preclude hormone action. Possible mechanisms of metabolic activation of the uterine luminal epithelium in the apparent absence of concentration of (3H) estradiol to nuclei of the luminal epithelium are discusse

ISSN:0022-104X    

DOI:10.1002/jez.1401970108

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

年代:1976

数据来源: WILEY

摘要:

AbstractTesticular morphology and plasma concentrations of luteinizing hormone (LH), testosterone, progesterone, and estradiol‐17βT were compared in paired (n = 8) and unpaired (n = 7) racing pigeons killed in December. The birds were housed mixed together under natural lighting conditions in two unheated lofts which contained no nesting facilities, in Kiel (54°N), Germany. The paired birds had been paired for at least two months. Testicular weights and diameters of tubules were significantly higher (p<0.05) in paired (1.64 ± 0.25 gm; 218 ± 12 μm) than in unpaired birds (0.79 ± 0.25 gm; 165 ± 20 μm). The testes of paired birds were spermatogenetically more active than those of unpaired birds. Plasma concentrations of some hormones concerned with reproduction were, in paired and unpaired birds respectively: LH, 2.28 ± 0.43 ng/ml and 0.98 ± 0.36 ng/ml (significantly different, p<0.1); testosterone, 1.24 ± 0.51 ng/ml and 0.59 ± 0.12 ng/ml (not significantly different); progesterone, 0.58 ± 0.08 ng/ml and 0.90 ± 0.12 ng/ml (significantly different, p<0.05); and estradiol‐17βT, 16.3 ± 0.95 pg/ml and 18.7 ± 2.25 pg/ml (not significantly different). Thus, the stimulatory effects of a mate on gonadotropin secretion and gonadal activity which have often been reported for female ring doves and domestic pigeons are also demonstrable in males during the late fall. Seasonal testicular regression in the unpaired males at this time of year was not prevented by the presen

ISSN:0022-104X    

DOI:10.1002/jez.1401970109

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects, of testosterone, 17βT‐hydroxy‐5α‐androstane‐3‐one (5α‐dihydrotestosterone; 5α‐DHT), 5α‐androstane‐3α, 17βT‐diol (3α‐androstanediol; 3α‐diol) and 5α‐androstane‐3βT, 17βT‐diol (3βT‐androstanediol; 3βT‐diol) on the development of fertilizing ability by spermatozoa in the epididymis were compared in castrated hamsters. The left corpus epididymidis was ligated for 14 days in intact and castrated animals to prevent the in‐flow of spermatozoa into the cauda epididymidis and the ductuli efferentes were bilaterally ligated. The fertilization rate of spermatozoa in the left cauda epididymidis of control animals decreased to 71.1% after 14 days whereas that of spermatozoa in the unobstructed right cauda epididymidis remained at the control level of 100%. After castration, 50 μg testosterone, 25 μg 5α‐DHT and only 9 μg 3α‐diol/day were the minimal doses that facilitated normal development of fertilizing ability but 75 μg testosterone, 37.5 μg 5α‐DHT and 12.5 μg 3α‐diol/day were required to maintain sperm survival at the control level. Howev

ISSN:0022-104X    

DOI:10.1002/jez.1401970110

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

年代:1976

数据来源: WILEY

摘要:

AbstractRana catesbianaadult frogs and tadples were immunized with the bacteriophage F2, ϕX‐174, and T4 and the haptens 2,4 dinitrophenyl (DNP) and fluorescein (FTC). The haptens were conjugated with bovine serum albumin (BSA), bovine gamma globulin (BGG), or horseshoe crab hemocyanin (Hycn). Sera were obtained from immunized animals at intervals up to six months after immunization. The antibody activities were measured by bacteriophage neutralization techniques. Sucrose density gradients were used to separate the antibody classes.Both adults and tadpoles responded to each of the antigens tested. High molecular weight antibodies were predominant in both groups of animals. Low molecular weight antibody activity was not found in adults until nine weeks post immunization but, thereafter, this fraction increased throughout the immune response. Low molecular weight antibodies could also be identified in serum of tadpoles, but only under certain conditio

ISSN:0022-104X    

DOI:10.1002/jez.1401970111

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

年代:1976

数据来源: WILEY