摘要:

AbstractThe influence of photoperiod on resting oxygen consumption and nonshivering thermogenesis of winter‐acclimatized kangaroo rats was determined by exposing freshly captured animals to 10‐week controlled photoperiod treatments. Three treatments were employed: (1) long days (LD) = 16L:8D, (2) short days (SD) = 8L:16D, and (3) short days interrupted with 15 min light at midnight (SDL). Thermoneutral oxygen consumption was uninfluenced by treatment, and posttreatment values were not different from pretreatment values. Below thermoneutrality, mean values for oxygen consumption and norepinephrine(NE)‐induced thermogenesis each were significantly greater in the SD group than they were in either the LD or SDL groups. Furthermore, oxygen consumption of LD and SDL groups, and NE‐induced thermogenesis of LD and SDL groups were indistinguishable. Posttreatment oxygen consumption and NE‐induced thermogenesis of the SD group were not different from pretreatment values. These results indicate that thermogenic capacities of kangaroo rats are strongly influenced by photoperiod. The similarities of responses by the LD and SDL groups indicate that the length of the dark period is of importance, and indirectly support suggestions that the pineal gland, through its nocturnal secretion of melatonin, may be involved in the transduction of photic in

ISSN:0022-104X    

DOI:10.1002/jez.1402340302

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

年代:1985

数据来源: WILEY

摘要:

AbstractDuring induction of anhydrobiosis the nematodeAphelenchus avenaesynthesizes large quantities of trehalose and free glycerol the carbon for which apparently originates from lipid. In the present paper we show that these worms possess a functional glyoxylate cycle by which lipid is converted to carbohydrate. Furthermore, we suggest a mechanism for regulation of the pathway during induction of anhydrobiosis.

ISSN:0022-104X    

DOI:10.1002/jez.1402340303

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe activities of the hydrolases, α‐L‐fucosidase, N‐acetyl‐β‐D‐glucosaminidase (NAG), and zpacoumase appear to be involved in the regression of the cement gland inXenopus laevis. The involution of the gland is marked by an important rise of the total as well as the specific activities of α‐L‐fucosidase and zpacoumase. The specific activity of α‐L‐fucosidase and of zpacoumase increases about five‐fold and eight‐fold, respectively, after 12 days of development. Although total activity of NAG decreases during involution, its specific activity undergoes an increase of 93% after 12 days. In contrast, there is a dramatic loss in the total and specific activity of aldolase, used as a control enzyme.The behaviour of these four enzymes is strikingly different in the epidermal tissue adjacent to the gland. Their activity remains stable during the developmental period considered. These observations demonstrate that possible contamination of the explanted gland by surrounding tissue is not responsible for the observed increase in hydro

ISSN:0022-104X    

DOI:10.1002/jez.1402340304

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe influence of removing portions of the growing antler of yearling red deer stags on subsequent regeneration of the antler in the same season was studied. The influence of the innervation of the antler on such regeneration was the subject of a further study. When the top 0.5–1 cm was removed from antlers 9–17 cm long, growth was slightly reduced in that season. When the antler/pedicle length was reduced to 6–10 cm in antlers 16–38 cm long, branched antlers regrew in 11 out of 13 cases provided the amputation was carried out early in the growing season, i.e., before mid‐December. Denervated antlers were shorter, lighter, and of different shape compared with controls, but they were of similar density. Denervation was confirmed histologically. Cleaning of velvet and casting of antlers following castration were unaffected by denervation. It would appear that although nerves affect the size and shape of the antler, they are not essential to the actual control of antler growth and reg

ISSN:0022-104X    

DOI:10.1002/jez.1402340305

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe present work deals with the determination of the threshold of nerve fibers per unit of amputation surface necessary for regeneration of the pectoral fins of a teleost,Fundulus. Partial denervation of the amputated pectoral fins, i.e., resection of one or two of the three nerves of the brachial (= pectoral) plexus revealed that the presence of a single one allows the amputated fin to regenerate. From these data and others obtained previously, it is concluded that the nervous requirements for a teleost fin to regenerate are similar or slightly lower than those for tetrapods, for example in the newt, which are capable of appendage regeneration.

ISSN:0022-104X    

DOI:10.1002/jez.1402340306

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe have measured the activities of the two rate controlling enzymes in polyamine synthesis, L‐ornithine decarboxylase (ODC) and S‐adenosyl‐L‐methionine decarboxylase (SAMDC), and the concentrations of the polyamines, putrescine, spermidine and spermine, in the developing chick embryo from laying to hatching. The embryo exhibited major peaks in the ODC and SAMDC activities as well as in the concentrations of all three polyamines at 15 h (gastrulation), 23–30 h (early organogenesis), days 4–5 (mid‐organogenesis), and days 12–17 (organ growth and maturation). In the 4 1/2‐day‐old embryo, ODC activity and polyamine concentrations were about twice as high in the head region as compared to the trunk region. In the 14‐day‐old embryo, the highest ODC and SAMDC activities were found in lung, intestine and kidney, and there was a positive correlation between the enzyme activities and the growth rates

ISSN:0022-104X    

DOI:10.1002/jez.1402340307

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe sperm of starfish (Asteroidea), sea cucumbers (Holothuroidea), and brittle stars (Ophiuroidea) are chemotactically attracted to the tip of a micropipette releasing very small volumes of egg water or seawater solution of an alcoholic extract of ovaries or spawned eggs. The sperm are unresponsive to injections of seawater or a weak solution of ammonium chloride in seawater. No other echinoderm tissue tested yields an extract with sperm‐attracting activity. A complex set of species‐specificities has been demonstrated between many of the genera and species used in these experiments. Plotting of the paths of chemotactic sperm reveals that they approach the tip of the pipette along a path consisting of small loops alternating with straight segments orientated directly up the gradient. This is similar to the chemotactic behavior previously reported for the sperm of hydrozoans, molluscs, and urochordates. Sperm velocity does not change in response to the sperm attractant. Attracted sperm remain motile long after they have been attracted and do not agglutinate. In at least some cases the attraction response is reversible. This is the first direct evidence of sperm chemotaxis in echinode

ISSN:0022-104X    

DOI:10.1002/jez.1402340308

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe mass changes of sodium, potassium, and calcium ions in the rat uterine secretion at blastocyst delay, activation, and attachment have been estimated with X‐ray microanalyses of samples of uterine secretions absorbed by small Sephadex beads. A quantification of the ions was attempted by using a standardized coat of gold on the beads as a reference element for normalization of the ion peaks and by fitting the normalized values into corresponding linear regression equations obtained from measurements of step‐wise dilutions of a control rat serum.The concentrations of sodium observed at delay, activation, and attachment were 117, 201, and 203 mEq/l, respectively, and those of potassium were 6, 18, and 19 mEq/l, respectively. Calcium values were about 2 mEq/l and decreased at attachment. Among the anions, only the chloride concentration increased at activation and attachm

ISSN:0022-104X    

DOI:10.1002/jez.1402340309

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

年代:1985

数据来源: WILEY

摘要:

AbstractThis study represents a follow‐up to earlier papers in which the initial stages of sperm penetration and cortical vesicle breakdown in activated eggs ofFundulus heteroclituswere described. Light and electron microscopy were used to examine later events of fertilization, second polar body formation, and changes in animal pole cytoplasm as the embryonic blastodisc forms. Fusion of sperm and egg plasmalemmae is quickly followed by the formation of a distinctive fertilization cone which persists for only 3 to 5 minutes. The protruding sperm flagellum disappears to the inside of the egg within 10 to 15 minutes. Inside the egg cytoplasm the sperm nucleus begins to undergo chromatin decondensation and nuclear envelope fragmentation as early as 20 seconds post‐insemination. In the egg the second meiotic spindle underlies the first polar body and the second polar body begins to form within about 3 minutes post‐insemination. The animal pole cytoplasm triples or quadruples in thickness within 3 minutes after insemination. It continues to thicken to form the definitive blastodisc by 1 to 1.75 hours after insemination. Details of changes in the surface topography of the egg which accompany these events are pres

ISSN:0022-104X    

DOI:10.1002/jez.1402340310

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

年代:1985

数据来源: WILEY

摘要:

AbstractFluid secreted by the rooster Wolffian duct contains several proteins separable on polyacrylamide gel electrophoresis (PAGE) and isoelectricfocusing (IEF) gels. Antibodies against these fluid components were obtained by immunizing rabbits, and the IgG fraction was then purified. As judged by indirect immunofluorescence, purified IgG against rooster duct fluid did not bind to any testicular spermatozoa. However, it bound distinctly to the whole surface of spermatozoa from the initial (epididymal) region and more intensely to all spermatozoa from the mid‐ and terminal regions of the Wolffian duct of the rooster, though not at all to mature duck or pigeon spermatozoa. Thus, in the rooster, as in therian mammals, the surface of the spermatozoon clearly acquires specific components secreted by the Wolffian duct. It should not be assumed that such surface change in rooster spermatozoa is entirely comparable, in a functional sense, to that undergone by mammalian spermatozoa, in which this seems directly related to fertilizing ability. Unlike those of mammals, rooster spermatozoa do not seem to require capacitation, and some spermatozoa in the testis already are competent to fertilize. Components acquired in the Wolffian duct by the rooster spermatozoon may bear on other aspects, perhaps sperm transport and/or survival in the femal

ISSN:0022-104X    

DOI:10.1002/jez.1402340311

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

年代:1985

数据来源: WILEY