摘要:

AbstractTo determine whether photogoreceptor degeneration in the Ozark cave salamander is associated with cessation or changes in the kinetics of outer segment (OS) renewal, an autoradiographic study of3H‐leucine incorporation in photoreceptors was carried out. Six days after isotope injection rods and cones showed labeling in both inner and outer segments. Cone OS were diffusely labeled whereas rods contained a band of radioactivity at the base of the OS. At 13 and 21 days the radioactive band in rods was located progressively nearer the distal tip of the OS. The rate of rod OS renewal ranged from 0.30 to 0.38 μ of OS length per day at 18°C. L‐thyroxin induced metamorphosis and light increased the renewal rate compared to larvae in darkness, and adults with photoreceptors in an early stage of degeneration had a slightly higher renewal rate than larvae. Light and electron microscope autoradiographs of degenerate photoreceptors revealed that even in the final stages of degeneration when OS are reduced to small, irregular whorls of membrane,3H‐leucine labeling was present in inner segments and OS membranes. These observations demonstrate that OS renewal occurs in both larvae and adults, and suggest that photoreceptor degeneration may be due to disruption of some aspect of the OS disposal

ISSN:0022-104X    

DOI:10.1002/jez.1401980302

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

年代:1976

数据来源: WILEY

摘要:

AbstractEffects of pH and egg water on the respiration of sea‐urchin spermatozoa were polarographically studied in three sea‐urchins and one starfish species. Sea‐urchin sperm respiration is extremely sensitive to change in the pH of the suspending medium over a wide range. In normal‐sea water, the pH of the sperm suspension decreased from 8.02 to 7.62, after four to five minutes' incubation at 18°C. The Respiratory Dilution Effect could be recognized in the same medium. However, when sea water was buffered with HEPES at pH 8.2, the Effect was no longer observed. The diffusate from egg water (jelly coat solution) brought about a striking increase in the respiration when added to moderately respiring spermatozoa in HEPES‐sea water of pH values lower than 7.9. No increase in the respiration was observed when the diffusate was added to vigorously respiring spermatozoa in HEPES‐sea water of pH values higher than 8.2. Sperm motility was also inhibited by acid pH, and this inhibition was reversed by the addition of the diffusate. It does not seem that there is any species‐specificity among three sea‐urchins and one starfish used. The role of the diffusate is discussed in relation to the penetration of spermatozoa through the jelly coat to

ISSN:0022-104X    

DOI:10.1002/jez.1401980303

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

年代:1976

数据来源: WILEY

摘要:

AbstractA sperm‐activating substance (SAS) was obtained from the jelly coat of sea‐urchin ova and its chemical properties were investigated in three seaurchin species. The SAS was partially purified from the jelly coat ofpseudocentrotuseggs through several steps of purification by procedures consisting of charcoal adsorption, on Sephadex G‐15 columns. The partially purified SAS was found to contain a ninhydrin‐positive material and is inactivated by pronase digestion. The molecular weight of SAS was estimated as about 630 by gel‐filtration through Sephadex G‐25, and the isoelectric‐point of SAS is located at about pH 5.3 by isoelectrofocusing method. The SAS is non‐volatile, alcohol‐soluble, and labile in a diluted alkaline or acid solution. The origin of

ISSN:0022-104X    

DOI:10.1002/jez.1401980304

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

年代:1976

数据来源: WILEY

摘要:

AbstractSexual dimorphism of antennal sense organs appears only at the adult stage during normal development of the cockroach,Periplaneta americana.Adult males acquire approximately twice as many olfactory sensilla as females at the terminal ecdysis. When terminal instar larvae are subjected to unilateral antennectomy, most ecdyse to supernumerary larvae rather than adults. Sexual dimorphism is not evident in the intact (unamputated) antenna during the extra larval stage, but appears at the following ecdysis which leads to the adult stage. Allatectomy of male and female larvae in the penultimate instar produces adultoids which show antennal sexual dimorphism. Whole‐body treatment of terminal instar larvae with exogenous juvenile hormone‐mimic (JH‐M) results in supernmerary larvae which lack antennal sexual dimorphism. When these superlarvae are removed from the influence of JH‐M, they ecdyse to adults with antennal sexual dimorphism. Topical application of JH‐M to male antennae early in the terminal larval instar results in the emergence of adults which lack the total male complement of antennal sensilla, but are otherwise normal‐appearing. These results indicate that an inhibitory action of juvenile hormone prevents the appearance of antennal sexual dimorphism during normal larval

ISSN:0022-104X    

DOI:10.1002/jez.1401980305

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

年代:1976

数据来源: WILEY

摘要:

AbstractMouse oocytes were found to sythesize proteins actively at the germinal vesicle, metaphase I, metaphase II, and pronuclear (6 hours post‐fertilization) stages. The qualitative pattern of protein components being sythesized in vitro, as demonstrated using polyacrylamide gel electrophoresis, changed throughout maturation and fertilization. Oocytes were arrested at metaphase I by ≥ 0.1 μg/ml cycloheximide or actinomycin D. The protein pattern in oocytes cultured in the presence of actinomycin D progresses to a metaphase II pattern in spite of the nuclear maturation arrest, indicating a dissociation between meiotic maturation and the changes in the pattern of proteins synthesized at different stages of matura

ISSN:0022-104X    

DOI:10.1002/jez.1401980306

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

年代:1976

数据来源: WILEY

摘要:

AbstractWild‐typeC. elegansand 16 derivative strains previously selected for defective attraction to NaCl and shown to carry single‐gene mutations were tested for their responses to nine chemical stimuli to which the wild‐type responds. These were the attractants Na+, Cl−, OH−, cyclic AMP, CO2in borate buffer, and pyridine and the repellents D‐tryptophan, CO2in phosphate buffer, and acid. All together 563 measurements were performed. Most strains were defective in most responses but responded normally to some chemical stimuli. In a few cases mutant strains avoided a chemical that attracted the wild‐type. Analysis of the patterns of defective responses among these mutants indicates that there are probably at least four different receptors. If results previously reported are included, the minimum number of receptors is increased to six. These mutations appear to have rather discrete effect

ISSN:0022-104X    

DOI:10.1002/jez.1401980307

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

年代:1976

数据来源: WILEY

摘要:

AbstractBullfrog tadpoles subjected to the daily disturbance of water replacement demonstrated differences in the rates of growth and metamorphosis and in fatbody weights which depended on the time of day when water replacement occurred. Early daily disturbances stimulated larval growth whereas midday disturbances stimulated metamorphosis. The time when the daily disturbances caused fattening changed during metamorphosis so that younger tadpoles fattened when disturbed early in the photoperiod and older tadpoles when disturbed at midday.

ISSN:0022-104X    

DOI:10.1002/jez.1401980308

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

年代:1976

数据来源: WILEY

摘要:

AbstractA polypeptide hormone, gonad‐stimulating substance (GSS), induces oocyte maturation and spawning in starfish through the production of 1‐methyladenine (1‐MA) in the follicle cells. Asterosaponin A (ASA) obtained from the ovary ofAsterias amurensisinhibits the spawning induced by the application of GSS on isolated ovarian fragments ofAsterias.The action of ASA is not ascribable to its surface‐active property since various natural and synthetic surface‐active agents failed to affect GSS‐induced spawning. ASA antagonized the action of 1‐MA in inducing spawning of isolated ovarian fragments. However, ASA did not inhibit 1‐MA‐induced maturation of isolated oocytes. When ovarian fragments were placed in sea water containing ASA and GSS or 1‐MA, oocytes inside the fragments underwent germinal vesicle breakdown. The application of acetylcholine to these ovarian fragments resulted in an immediate shedding of mature oocytes. ASA did not affect calcium‐induced spawning in the ovarian fragments which were pretreated with calcium‐free sea water to dissolve

ISSN:0022-104X    

DOI:10.1002/jez.1401980309

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

年代:1976

数据来源: WILEY

摘要:

AbstractAllophenic mice have been produced by combining embryos from normal albino mice with embryos of normally pigmented mice carrying the autosomal dominant for sex reversed (Sxr) in order to determine the ability of XXSxr cells to differentiated either into sperm or eggs. Sixteen male and six female allophenes have thus far produced more than 1,200 offspring, none of which arose from an XXSxr primordial germ cell. Two allophenic mice were sterile hermaphrodites, and 13 others have yet to be tested. These results indicate that an XX cell is incapable of spermatogenesis even when supplied with the male determining Sxr gene, and that this gene also prevents XX cells from undergoing oogenesis. The latter result contrasts with a previous report of a functional sex reversed oocyte in the mouse.

ISSN:0022-104X    

DOI:10.1002/jez.1401980310

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

年代:1976

数据来源: WILEY

摘要:

AbstractA method is described for the dissociation of mouse ovaries and the isolation of oocytes free of somatic cells by agitating pieces of ovary in collagenase and deoxyribonuclease in a calcium and magnesium free salt solution. This method yielded about 50% of the growing oocytes from immature mice.The utilization of exogenously administered14C‐labelled energy sources by oocytes in various growth stages was determined by measurement of evolved14CO2. Little or no evolution of14CO2was detected from oocytes of any size incubated in14C‐glucose, lactate or succinate. The production of14CO2from14C‐pyruvate increased logarithmically when plotted against increasing oocyte volume with a plateau occurring after oocytes reached a volume of 65,500 μm3(50 μ diameter). Thus, the pattern of energy metabolism for oocyte maturation and early egg cleavage, wherein glucose and lactate are not utilized as efficiently as pyruvate, has been established by the earliest stages of oocyte

ISSN:0022-104X    

DOI:10.1002/jez.1401980311

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

年代:1976

数据来源: WILEY