bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of slow and ultra‐rapid freezing on cell surface antigens of 8‐cell mouse embryos
Authors: Wood Maureen J. , Sjöblom Peter , Lindenberg Svend , Kimber Susan J.
Published: June 2005

The distribution of four cell surface antigens (SSEA‐1, SSEA‐3, SSEA‐4, and I) present on mouse preimplantation embryos was examined on 8‐cell stage embryos immediately after flushing from the reproductive tract and after slow or ultra‐rapid freezing. Frozen‐thawed and nonfrozen embryos were also examined after culture in vitro for 5, 24, or 48 h. Immediately after thawing, embryos showed a disruption in the polarity of cell surface antigens SSEA‐3, SSEA‐4, and I, but no differences were detected in fluorescence intensity or various other staining characteristics. No long‐term changes in the distribution of cell surface components were detected. Implantation and embryonic development were similar for frozen and nonfrozen embryos transferred to the uterine horns of pseudopregnant recipients. © 1992 Wiley‐Liss, Inc.
Effects of short‐term 17β‐estradiol treatment on the properties of T4‐binding proteins in the plasma of immature rainbow trout, Oncorhynchus mykiss
Authors: Cyr Daniel G. , Eales J. G.
Published: June 2005

To determine the effects of 17β‐estradiol (E2) on the properties of the plasma proteins that bind L‐thyroxine (T4), immature rainbow trout, Oncorhynchus mykiss, were injected intraperitoneally on days 0 and 3 with 0.5 mg E2‐3‐benzoate/100 g body weight, and plasma was sampled on days 4, 7, or 12. Control trout received peanut oil alone. E2 caused a small but significant decrease in the free T4 index. Saturation analysis on miniature G‐25 Sephadex columns revealed at least two major T4‐binding sites. Filtration on agarose Bio‐gel A 1.5 also indicated two major T4‐binding protein fractions with molecular weights of 150 and 55 kDa with a small proportion of T4 binding to a 1,500‐kDa site presumed to be lipoprotein. Addition of unlabeled T4 displaced [125I]T4 from the 55‐kDa site and unmasked an adjacent site of higher molecular weight. E2 increased the proportion of T4 bound to the low‐affinity (150 kDa) site relative to that bound to the high‐affinity (55 KDa site, increased the level of protein associated with the 1,500‐kDa site and its T4 binding, and also initiated the production of presumed vitellogenin (VTG), which bound a small amount of T4. It is concluded that the E2‐induced depression in FT4 is caused by a shift in T4 binding between high‐affinity and low‐affinity sites, and also by binding of small amounts of T4 to presumed lipoprotein and VTG. © 1992 Wiley‐Liss, Inc.
Regenerative responses in cultured hindlimb stumps of larval Xenopus laevis
Authors: Cannata Stefano M. , Bernardini Sergio , Filoni Sergio
Published: June 2005

The regenerative capacity of larval Xenopus laevis hindlimbs amputated through the tarsalia at different stages of development and explanted in vitro was tested. In the first experimental series hindlimb stumps from stage 53, 54, 55, and 57 larvae (according to Nieuwkoop and Faber, '56) were cultured in Leibovitz's L‐15 medium supplemented with 10% FCS, and 0.04 U of insulin and 10−8mg of L‐thyroxine per ml of medium. Results showed that the distal part of the limb stumps from stages 53, 54, and 55 formed a regeneration blastema composed of proliferating mesenchymal cells beneath a typical apical cap. No blastema was formed in the proximal part of the stump. In limb stumps from stage 57, a regeneration blastema did not form either in the proximal or in the distal part of the stump. In a second experimental series, hindlimb stumps from stage 55 larvae, denervated 5 days prior to amputation in order to eliminate any residual neurotrophic factor, were cultured in a simplified L‐15 medium containing 2% FCS and lacking insulin and thyroxine. Results showed that also in these experimental conditions the stumps from stage 55 formed a conical regeneration blastema at the distal tip. The blastema cells duplicated their own DNA and divided. At the proximal extremity no regeneration blastema was formed. In the same culture medium, the stumps of larvae at stage 57 did not form a regeneration blastema. Overall these results confirm those obtained in vivo on denervated and amputated limbs of larval Xenopus (Filoni and Paglialunga: Differentiation 43:10–19, 1990), namely, that the early stage limbs are able to form a regeneration blastema in the absence of nerves while the late stage limbs are nerve‐dependent for regeneration. The capacity of the early stage limbs for forming a regeneration blastema on the distal tip seems related to the presence, in the amputation area, of a population of undifferentiated mesenchymal cells capable of proliferating in the absence of mitogenous nerve factors. © 1992 Wiley‐Liss, Inc.
Intracellular pH regulation and metabolic interactions in hepatic tissues
Authors: Walsh Patrick J. , Mommsen Thomas P.
Published: June 2005

Intracellular pH (pHi) regulation in the vertebrate liver relies heavily on ionic transport mechanisms. Liver, in common with many tissues, has plasma membrane Na+‐H+ and Cl−‐HCO3− electroneutral exchangers which work in opposition to tightly control pHi. Mammalian livers also possess electrogenic Na+‐HCO3 exchangers, capable of base uptake, which, when coupled to pHi‐mediated changes in membrane potential, probably confer an additional measure of pHi control, compared to fish livers, where the transporter appears to be functionally absent. It is suggested that this may be a fundamental difference between aquatic and aerial breathing. pHi regulation has barely been examined in invertebrate hepatic tissues, but already some interesting differences are apparent. Notably, an electrogenic 2Na+ ‐1H+ acid‐extrusion system is present in apical membranes of crustacean hepatopancreas. Despite these ionic control systems, complex acid‐base disturbances (e.g., “metabolic” acidosis) have been known for some time to influence hepatic metabolism in vertebrates, but few studies have carefully examined the independent effects of the acid‐base variables involved. Thus mechanistic explanations for the effects of acid‐base disturbances are scarce. Ureogenesis in mammals has been well studied, and several pH‐related mechanisms are evident. In contrast, the pH‐insensitivity of ureogenesis in fish liver may represent a second difference between aquatic and terrestrial species. In summary, by virtue of its metabolic diversity, liver represents a potentially important organ in acid‐base balance, and an interesting study tissue for interrelationships between metabolism and acid‐base balance. © 1992 Wiley‐Liss, Inc.
Steroidogenesis in Fundulus heteroclitus. IV. Dichotomous effects of a phorbol ester on ovarian steroid production and oocyte maturation
Authors: Petrino Teresa R. , Lin Yu‐Wai P. , Wallace Robin A.
Published: June 2005

The possible role of protein kinase C (PKC) activation in mediating the stimulatory actions of a Fundulus pituitary extract (FPE) on ovarian steroidogenesis and oocyte maturation was investigated. The phorbol ester, phorbol 12‐myristate 13‐acetate (PMA), alone slightly increased basal 17α‐hydroxy, 20β‐dihydroprogesterone (DHP) and 17β‐estradiol (E2) synthesis and significantly stimulated germinal vesicle breakdown (GVBD). Addition of FPE promoted synthesis of DHP, testosterone (T), and E2, and initiated GVBD. Phorbol ester inhibited FPE‐induced steroidogenesis but increased the number of oocytes that underwent GVBD. Phorbol ester also markedly impeded induction of steroidogenesis by dibutyryl cAMP and differentially affected the conversion of 25‐hydroxycholesterol, pregnenolone, or progesterone to DHP, T, and E2: DHP production was not affected; T production diminished; and E2 synthesis increased (T aromatization also increased). These results suggest an inhibitory role for the PKC pathway on FPE‐induced ovarian steroid production, with PMA appearing to affect various steroidogenic steps. The stimulatory action of PMA on oocyte maturation seems to be independent of follicular steroid production since aminoglutethimide, an inhibitor of steroidogenesis, did not block PMA‐induced GVBD. Moreover, PMA had a marked stimulatory effect on GVBD in denuded oocytes. Thus, in contrast to the inhibitory role found for the PKC pathway on ovarian follicular steroidogenesis, activation of PKC in the oocyte may serve as a signal‐transducing mechanism leading to GVBD. © 1992 Wiley‐Liss, Inc.
In vivo effects of the steroid analogue RU486 on some aspects of intermediary and thyroid metabolism of brook charr, Salvelinus fontinalis
Authors: Vijayan M. M. , Leatherland J. F.
Published: June 2005

The glucocorticoid analogue RU486 was administered by intraperitoneal injection to brook charr (Salvelinus fontinalis) to further explore the role of cortisol on aspects of intermediary and thyroid hormone metabolism of the species.

RU486 significantly elevated the hepatosomatic index, hepatic G3PDH activity, and hepatic glycogen content, but was without effect on hepatic protein content, hepatic FPBase activity, or plasma glucose concentration. However, the stressor‐related increase in plasma glucose concentration that was evident in brook charr 24 h following handling and injection was suppressed in RU486‐treated groups.

The distribution volume, turnover rates, and metabolic clearance rates of [3H]cortisol were similar in RU486‐ and vehicle‐treated groups.

Plasma T3 and T4 concentrations were similar in RU486‐ and vehicle‐treated groups, but hepatic T3 production and hepatic T3 content were lower in RU486‐treated fish; TSH had no effect on hepatic T3 content of vehicle‐treated brook charr but significantly increased T3 content in the RU486‐treated group. These observations support the concept of a role of cortisol in the control of peripheral monodeiodination of T4 in salmonid fish and suggest that RU486 may be a useful drug for evaluating the role of cortisol in fish in vivo. © 1992 Wiley‐Liss, Inc.
CHox‐cad locus may influence quantitative traits in chickens
Authors: Iraqi Fuad , Khatib Hasan , Shani Gilat , Davarsi Ariel , Frumkin Ayala , Zeitlin Gadi , Soller Morris , Fainsod Abraham , Gruenbaum Yosef
Published: June 2005

Restriction fragment length polymorphism analysis of BamHI digested chicken DNA with a chicken CHox‐cad homeobox gene probe uncovered two CHox‐cad RFLP alleles. The relation between the RFLP alleles and several quantitative traits was analyzed in two chicken populations having widely different genetic backgrounds: a broiler line and a layer cross. Allelic frequency differed significantly in the broiler line as compared to the egg layer cross. Significant RFLP‐associated effects were found for age at first egg in the layer cross, and for mature body weight and percentage egg production in the broiler cross. © 1992 Wiley‐Liss, Inc.
Protamines, not histones, are the predominant basic proteins in sperm nuclei of solitary ascidian tunicates
Authors: Chiva M. , Lafargue F. , Rosenberg E. , Kasinsky H. E.
Published: June 2005

In this work we study the protein content in sperm nuclei from 10 species of ascidian tunicates. The 7 species that we have investigated cytochemically show type 3 intermediate sperm basic proteins, as observed previously for the solitary tunicate Styela montereyensis (Chiva, Rosenberg, and Kasinsky, J. Exp. Zool., 253:7–19, 1990). We have focused this study on two specific points: the presence of protamines and the presence of somatic histones. In 4 species belonging to the suborder Phlebobranchiata, sperm nuclei contain only a protein more basic than histones (protamine). This protamine has an electrophoretic mobility similar to core histone H4. The nuclei of sperm in the species belonging to the suborder Phlebobranchiata are also characterized by their complete lack of somatic histones. In 5 species from the suborder Stolidobranchiata, sperm nuclei contain a similar protamine. However, 2 species from the genus Styela contain additionally other protamines with different electrophoretic mobilities. For all species belonging to the suborder Stolidobranchiata, we also have found very small quantities of residual somatic histones. We conclude that during the process of spermiogenesis in ascidian tunicates protamines replace histones either completely (Phlebobranchiata) or almost completely (Stolidobranchiata). In this respect spermiogenesis in tunicates (class Ascidiacea) is similar to that in vertebrates which, in general, also display the substitution of somatic histones by protamines. On the other hand, this model is different from that in echinoderms, where the protein content of sperm nuclei consists mainly of somatic histones and sperm‐specific variants of histones. © 1992 Wiley‐Liss, Inc.
Mouse limb bud cells respond to retinoic acid in vitro with reduced growth
Authors: Gardiner D. M. , Gaudier C. , Bryant S. V.
Published: June 2005

Retinoic acid (RA) has dramatic effects on the pattern of developing and regenerating vertebrate limbs. These effects are considered to result from RA‐induced changes in the positional identity of limb cells, and involve the formation of extra structures. Whether the growth required to form the supernumerary parts of the pattern is a primary effect of RA treatment or a secondary effect that follows after a change in positional identity is not at present known. In this paper we have investigated the effects of RA treatment on the growth of cells from anterior and posterior halves of mouse limb buds in vitro. We observed that under our culture conditions, limb bud cells treated with 1 nM to 1 μM RA (0.3 ng/ml to 300 ng/ml) continue to grow but do so at a significantly slower rate than control cultures. There is a maximum inhibition of growth (50% of controls) between 10 nM and 100 nM RA, which corresponds to the measured range of concentrations of RA in vivo. Our observation of a significant decrease in growth rate over a wide range of RA concentrations is consistent with comparable reports of growth inhibition for a large number of other cell types in vitro as well as with the observation that exogenous RA inhibits blastemal growth in amphibians during the period of exposure to RA. We propose that the effects of RA on growth, either enhancement in vivo or reduction in vitro, can be seen as consequences of the ability of RA to alter positional identity. Hence, when RA is administered to limb cells in vitro, it is likely that the non‐posterior cells in both anterior and posterior cultures are converted to posterior identity. The resulting decrease in growth can be interpreted as a consequence of the increased uniformity of positional information in vitro. © 1992 Wiley‐Liss, Inc.
Retinoic acid respecifies limb bud cells in vitro
Authors: Hayamizu Terry F. , Bryant Susan V.
Published: June 2005

Retinoic acid (RA) is known to have dramatic effects on limb pattern formation and has been shown to exert its effects on limbs by converting anterior limb bud cells into cells with posterior positional properties. In this study we find that dissociated posterior limb bud cells from chick and mouse embryos cultured at high density (micromass cultures) are able to stimulate the formation of supernumerary digits when grafted into developing wing buds and that the positional identity of both chick and mouse limb bud cells can be maintained for finite periods of time in vitro. Furthermore, using this assay system we have tested whether anterior cells from mouse and chick limb buds can be converted into cells with posterior identity by exposure to RA in vitro. We find that anterior limb bud cells acquire posterior properties after culture in the presence of RA. © 1992 Wiley‐Liss, Inc.
Physiological responses to carbon dioxide in embryonic red‐eared slider turtles, Trachemys scripta
Authors: Etchberger Cory R. , Ewert Michael A. , Phillips John B. , Nelson Craig E. , Prange Henry D.
Published: June 2005

In the red‐eared slider turtle, Trachemys scripta, sex is determined by the incubation temperature of the egg: warm temperatures produce females, cool ones produce males, and a narrow range of intermediate temperatures produce both sexes. We asked whether the influence of temperature is modified by the effects of carbon dioxide. Under one current hypothesis, sex is more closely linked to total incubation time and than to temperature. Higher levels of carbon dioxide should lengthen total incubation time and thus mimic the longer incubation times produced by low incubation temperatures. By this hypothesis longer incubation times should increase the tendency to produce males. Trachemys scripta eggs were incubated in atmospheres containing various concentrations of carbon dioxide. While total incubation times were significantly lengthened with elevated carbon dioxide (as if mimicking cool temperatures), sex ratios were altered in favor of females (as if mimicking warm temperatures). This result is compatible with a hypothesis that pH changes affect sex in turtles with TSD. Turtles incubated at elevated levels of carbon dioxide absorbed less yolk, and had more residual yolk, and were somewhat smaller than turtles incubated at lower of carbon dioxide. In some cases, clutches were heterogeneous in their responses to the various levels of carbon dioxide. © 1992 Wiley‐Liss, Inc.
An attempt to determine the mechanisms of Cl−‐exit across the basolateral membrane of eel intestine: Use of different cl−‐transport pathway inhibitors
Authors: Trischitta F. , Denaro M. G. , Faggio C. , Schettino T.
Published: June 2005

The possible mechanisms of Cl−‐exit across the basolateral membrane of the enterocyte in sea water (SW) and freshwater (FW) eel intestine were investigated by observing the response of the short‐circuit current, Isc, equivalent to net Cl−‐absorption, and transepithelial voltage, Vt, to specific or relatively specific inhibitors of different Cl−‐transport pathways. Serosal NPPB [5‐nitro‐2(3 phenylpropylamino)‐benzoate] (10−4 M), the potent blocker of Cl−‐channels in different epithelia, produced a negligible effect on Isc and Vt either in presence or in absence of HCO3− in the bathing solutions. In the presence of HCO3− serosal bumetanide, better than furosemide and torasemide, at a concentration of 10−4 M inhibited Isc and Vt by ∼90% within 15–30 min without changing the transepithelial resistance, Rt. In HCO3−‐free solutions the drug completely collapsed Isc and Vt. The results were similar in both SW and FW eels. In SW fishes serosal SITS (2.5 × 10−4 M) reduced Isc and Vt by ∼50% when HCO3− was present in the solutions. In absence of HCO3− SITS inhibited Isc and Vt by ∼35%, a finding consistent with the presence of a Cl−‐conductance in the basolateral membrane. Under these conditions SITS inhibition disappeared after bumetanide pretreatment. There is little evidence for the presence of a basolateral K+‐conductance since serosal Ba2+ (1 mM) elicited variable effects on Isc and Vt.

The results are interpreted as evidence for the presence of bumetanide‐ and SITS‐sensitive Cl−‐ conductance channels in the basolateral membrane of SW and FW eel intestine which would contribute at least 35% of the net Cl−‐absorption. An HCO3−‐dependent Cl−‐transport was also identified since Isc and Vt were reduced by ∼50% when tissues were perfused with HCO3−‐free salines. © 1992 Wiley‐Liss, Inc.
Effects of an augmented nerve supply on forelimb regeneration in the adult mud frog, Rana rugosa
Authors: Kurabuchi Shingo
Published: June 2005

Forelimbs of the adult mud frog Rana rugosa, when amputated midway through the zeugopodium, regenerate heteromorphically. The resulting regenerative outgrowths were mostly rod shaped and consisted of a cartlaginous core, in which the base was ossified, and muscle elongated distally along the cartilage, the whole being covered by connective tissue and skin. The tip of the regenerating muscle reached a point distally about one third of the length of the regenerative outgrowths. When the innervation of forelimb stumps was augmented by surgical diversion of the ipsilateral sciatic nerve, the amputated limbs regenerated mostly as spatula‐shaped outgrowths, which were longer those of normally innervated forelimbs. Such hyperinnervated regenerates exhibited less ossification of cartilage, or sometimes none at all. However, the regeneration of muscle was more extensive. That is, it reached more than half way along the regenerative outgrowth. Furthermore, denervation resulted in the absence of regeneration in all cases examined. Theses results clearly indicate that limb regeneration in Rana rugosa is dependent upon the degree of innervation, not only for the early stages of regeneration, but also for the growth and differentiation of the regenerative outgrowth. © 1992 Wiley‐Liss, Inc.
Gynogenetic mechanisms in polyploid hybrid salamanders
Authors: Elinson Richard P. , Bogart James P. , Licht Lawrence E. , Lowcock Leslie A.
Published: June 2005

Polyploid hybrid salamanders of the genus Ambystoma tend to produce unreduced eggs. At higher temperatures (15°C), the sperm often contributes genetically, leading to tetraploid offspring from triploid mothers and pentaploid offspring from tetraploid mothers. At lower temperatures (5°C), the sperm nucleus usually is lost, and the eggs develop gynogenetically. We examined the cytology of fertilization at 5°C in order to determine the nature of the temperature‐dependent nuclear loss. As in other urodeles, fertilization is polyspermic. The sperm nuclei decondense to form pronuclei, and one sperm pronucleus associates with the egg pronucleus. At metaphase, a clump of chromatin appears along with the chromosomes at the metaphase plate. This chromatin clump fails to segregate at anaphase and is left at the site of the cleavage furrow. The chromatin clump is likely the discarded sperm pronucleus, so its loss is due to its failure to condense properly into chromosomes. © 1992 Wiley‐Liss, Inc.
Vitellogenin diversity in the perciformes
Authors: Lee K. B. H. , Lim E. H. , Lam T. J. , Ding J. L.
Published: June 2005

Vitellogenin variation was studied in 11 species of Perciformes encompassing the families Cichlidae, Serranidae, Lutjanidae, Centropomidae, and Eleotrididae. Despite the enormous morphological and ecological diversity that characterizes this order of teleosts, northern blot analysis revealed that the Oreochromis aureus vitellogenin gene probe will recognize estradiol‐induced vitellogenin messenger RNA of distant percoid relatives under stringent conditions of hybridization, suggesting that the vitellogenin gene is well conserved at least within the suborder Percoidei. Multiple vitellogenin gene transcripts were detected in the Cichlidae and these are correlated with the finding of multiple vitellogenin protein monomers in this family. In other families of non‐cichlid percoids, only one vitellogenin transcript, and, correspondingly, a single vitellogenin monomer was observed. No cross hybridization was, however, observed with a representative of the suborder Gobioidei. The pattern of protein bands seen in SDS‐PAGE also differed. The main features of vitellogenin protein diversity in the Perciformes are interfamily variability in size and subunit number. © 1992 Wiley‐Liss, Inc.
Spontaneous ovarian contractions in Fundulus heteroclitus
Authors: Bartley Susan M. , Kippax Jill B. , Taylor Malcolm H.
Published: June 2005

Spontaneous contractions of Fundulus heteroclitus ovaries were observed and quantified using 2 methods. Contractions were measured as increases in intraovarian pressure in ovaries retained in the fish and as tension changes in ovaries removed from the fish, suspended in a smooth muscle bath, and connected to a force transducer. Spontaneous contractions were observed in approximately one‐half the ovaries tested, using both methods. The occurrence of spontaneous contractions was dependent on the reproductive stage of the fish, with more sexually mature fish exhibiting a greater incidence of spontaneous activity. The rate of contraction increased linearly with temperature over the range 20–35°C. Although the physiological significance of ovarian contractions in F. heteroclitus is unclear, possible functions include the facilitation of ovulation, egg release during spawning, and the movement of eggs or fluid within the ovary. © 1992 Wiley‐Liss, Inc.
Microfilaments, cell shape changes, and the formation of primary mesenchyme in sea urchin embryos
Authors: Anstrom John A.
Published: June 2005

Primary mesenchyme formation in sea urchin embryos occurs when a subset of epithelial cells of the blastula move from the epithelial layer into the blastocoel. The role of microfilaments in producing the cell shape changes that characterize this process, referred to as ingression, was investigated in this study. f‐Actin was localized by confocal microscopy using labeled phalloidin. The distribution of f‐actin was observed before, during, and after ingression and was correlated with cellular movements. Prior to the onset of ingression, staining became intense in the apical region of putative primary mesenchyme and disappeared following the completion of mesenchyme formation. The apical end of these cells constricted coincidentally with the appearance of the intensified staining, indicating that f‐actin may be involved in this constriction. In addition, papaverine, a smooth muscle cell relaxant that interferes with microfilament‐based contraction, and that was shown in this study to inhibit cytokinesis, diminished apical constriction and delayed ingression. Despite this interference with apical constriction, the basal surface of ingressing cells protruded into the blastocoel. It is suggested that apical constriction, while not necessary for ingression, does contribute to the efficient production of mesenchyme and that protrusion of the basal surface results from changes that occur independent of apical constriction. © 1992 Wiley‐Liss, Inc.
Fat body ovarian relationship in the garden lizard, Calotes versicolor (Daud.)
Authors: Shanbhag Bhagyashri A. , Prasad B. S. Krishna
Published: June 2005

Abdominal fat body mass of Calotes versicolor showed annual changes that were universal related to the changes in ovarian somatic (GSI) and hepatosomatic (HSI) indices. Fat bodies were absent in late breeding phase (June–August). Thirty day fatectomy (FBX) during prebreeding phase significantly reduced GSI, HSI, and total number of extrastromal follicles; also, recruitement of vitellogenic follicles was arrested and ateretic follicles increased. The FBX during postbreeding phase had no such effect, whereas in 30 day ovariectomised (OvX) lizards in prebreeding phase fat body mass significantly increased but HSI decreased. However, in lizards in prebreeding phase, E2 caused a significant decrease in fat body mass and an increase in HSI, while during the postbreeding phase there was a significant increase in HSI but the fat bodies were not affected.

The above findings suggest that the development of the first clutch of vitellogenic follicles in the lizard utilises lipids stored in the fat bodies and that the growth of the subsequent clutches of vitellogenic follicles is met through the intake of food, which is abundant in the latter part of the breeding phase. The fat bodies are not needed for the growth of previtellogenic follicles. The fact that lipolytic action of E2 occurs only during the breeding phase suggests that responsiveness of the fat bodies to the steroid is related to the reproductive phase and that during postbreeding phase of the lizard they become refractory to E2. © 1992 Wiley‐Liss, Inc.
Influence of a capacitation period on human sperm acrosome loss
Authors: Holden Carol A. , Trounson Alan O.
Published: June 2005

The present study investigates whether a 5 hour capacitation period modifies the ability of human spermatozoa to undergo induced acrosomal loss. Human sperm acrosomal loss was induced by treatment with either the calcium ionophore A23187, low concentrations of the phospholipid dilauroylphosphatidylcholine (PC12), or 2 hours incubation in conditioned medium prepared from human cumulus cells (CM/CC). The use of a dual staining method (FITC‐ConA and Hoechst 33258) for simultaneous assessment of acrosomal status and viability demonstrated that induction of acrosomal loss with calcium ionophore was not dependent on a capacitation period. A short (5 hour) incubation period was not sufficient to induce acrosomal loss with CM/CC above spontaneous acrosome reaction rates in medium alone. A significant capacitation‐dependent increase (P < 0.05) in acrosomal loss was observed when human spermatozoa were incubated with PC12. Induction of acrosomal loss of capacitated human spermatozoa with PC12 therefore provides a simple assay for the simultaneous assessment of human sperm capacitation and the acrosome reaction in vitro. © 1992 Wiley‐Liss, Inc.
Structure of the vaginal plugs generated by normal rats and by rats with partially removed seminal vesicles
Authors: Carballada R. , Esponda P.
Published: June 2005

Normal male rats generate vaginal plugs that appear to be firmly apposed to the vagino‐cervical junction and permit a large number of spermatozoa to reach the uterus. A few spermatozoa form entangled masses inside these plugs, as revealed by light microscopy. Males in which the seminal vesicles have been partially removed produce plugs that are smaller and softer than those generated by normal males, and the plugs display a cup‐like structure at the proximal end. The cup‐like structure is completely filled with spermatozoa that exhibit a characteristic arrangement in relation to the plug material. In this situation, the number of spermatozoa that reach the uterus is very much reduced. Experiments were also carried out to explore the restoration of sperm transport by addition of a vaginal plug. Such experiments involved successive matings of individual females with a seminal vesicle‐deprived male and with a vasectomized male (which generated the plug) and also the intravaginal injection of seminal vesicle secretions after mating with a seminal vesicle‐deprived male. In none of the experimental situations was transport of spermatozoa to the uterus restored, and the plug consisted of a large quantity of trapped spermatozoa inside a mass of coagulated proteins. The results suggest that the structure of the plug depends on the amount of seminal vesicle secretion present in the ejaculate and that the vaginal plug must be formed immediately after deposition of the sperm if spermatozoa are to reach the uterus. © 1993 Wiley‐Liss, Inc.
Differential degradation of myofibrillar proteins by four calcium‐dependent proteinase activities from lobster muscle
Authors: Mattson Joanne M. , Mykles Donald L.
Published: June 2005

Four calcium‐dependent proteinases (CDPs I, IIa, IIb, and III) were isolated from lobster claw and abdominal muscles. In order to determine the substrate specificities of the CDPs, each enzyme was incubated with either native purified myosin or actomyosin from lobster deep abdominal muscles. After incubation in the presence or absence of 5 mM Ca2+, reaction mixtures were separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and examined in 2 ways: (1) the fragment patterns from the degradation of the myosin heavy chain were identified with immunoblotting, and (2) gels were stained with Coomassie blue and densitometrically scanned to quantify the degradation of the major myofibrillar proteins. CDPs IIa and IIb were the most effective in degrading myosin heavy chain, actin, troponin‐T2, tropomyosin, troponin‐I1 and ‐I5, troponin‐C1, and myosin β‐light chain; the major difference between the 2 enzymes was that CDP IIa also degraded myosin α‐light chain. CDP III effectively hydrolyzed myosin heavy chain, actin, troponin‐T2, tropomyosin, troponin‐I5, troponin‐C1, and myosin β‐light chain. CDP I was the least efficient of the 4 CDPs in degrading myofibrillar proteins; only actin, troponin‐T2, and troponin‐I5 were readily hydrolyzed. All the CDPs recognized similar cleavage sites within the myosin heavy chain, since the proteolytic fragment pattern produced by each enzyme on the myosin heavy chain in reaction mixtures containing either actomyosin or myosin was essentially identical. These results show that the 4 CDPs share catalytic properties but differ in substrate specificities, particularly when presented with a complex assemblage of potential substrates. © 1993 Wiley‐Liss, Inc.
Brain evolution in decapod crustacea
Authors: Sandeman D. C. , Scholtz G. , Sandeman R. E.
Published: June 2005

A survey of the morphology of the brains (cerebral ganglia) of 13 species of decapods shows that all have common areas of neuropil that are developed to differing degrees in the different groups. The neuropils of the paired accessory lobes, however, appear to have evolved de novo in the Reptantia. Phylogenetic relationships within the Reptantia suggest that the accessory lobes were initially large but became reduced in size during the evolution of the brachyurans and anomalans. © 1993 Wiley‐Liss, Inc.
Uncoupling the correlates of locomotor costs: A factorial approach
Authors: Myers M. J. , Steudel K. , White S. C.
Published: June 2005

Although the metabolic cost of running has been found to vary systematically with running speed and body mass in animals, no mechanistic model of cost determination has been widely accepted. Because two suggested cost determinants—mechanical power output and the rate of force application—covary with running speed when gait (stride frequency) is unconstrained, examining the influence of each factor on cost has been problematic.

We experimentally uncoupled the usual relationships between three readily manipulated cost correlates—speed, stride frequency, and mass distribution—to study the determinants of the cost of running in humans along a section of the cost response surface. Two levels of each cost correlate were used in a factorial design in which subjects ran at all eight combinations of factor levels while rate of oxygen consumption (
equation image
), mechanical power, and contact time were measured as response variables. Contact time and mechanical power were measured from high‐speed cinefilm.

Mechanical power accounted for 88%, and contact time (rate of force application) 57%, of speed‐related
equation image
variation. Variation in cost produced by changes in stride frequency and mass distribution were largely explained by mechanical power. Contact time was not significantly correlated with overall variation in
equation image
, while mechanical power output explained 80% of that variation. For the range of conditions tested, we conclude that the mechanical power derived from muscular contractions is an important determinant of the cost of running. While we have shown that the rate at which muscles shorten is not the sole determinant of the cost of running, the extent to which this factor influences cost remains unclear. © 1993 Wiley‐Liss, Inc.
Functional and structural characterization of hemocytes of the solitary ascidian, Halocynthia roretzi
Authors: Azumi Kaoru , Satoh Noriyuki , Yokosawa Hideyoshi
Published: June 2005

In invertebrates, hemocytes play important roles in defense mechanisms. The hemocytes of a solitary ascidian, Halocynthia roretzi, are a source of two antibacterial substances (halocyamines) and a lipopolysaccharide‐binding (LPS‐binding) hemagglutinin that is capable of agglutinating various bacteria. Furthermore, a metallo‐protease is released from the hemocytes in response to treatment with LPS, a calcium ionophore, or phorbol ester. In the present study, we attempted to fractionate the hemocytes to determine which of them contain the LPS‐binding hemagglutinin and release the metallo‐protease in response to various stimuli. The hemocytes of H. roretzi can be separated into five groups (L1‐L5) by discontinuous density gradient centrifugation in a solution of bovine serum albumin. The various populations of hemocytes exhibit structural differences that can be monitored by electron microscopy and flow cytometric analysis. The LPS‐binding hemagglutinin, together with halocyamines, was found in group L5, which consists of only one type of hemocyte. The hemocytes in groups L1, L3, and L4 released the metallo‐protease in response to various stimuli, whereas at least those in group L5 did not. These results indicate that the various groups of hemocytes of H. roretzi can be distinguished functionally from one another on the basis of cellular responses and the ability to produce defense substances. © 1993 Wiley‐Liss, Inc.
Comparison of the renal sodium‐D‐glucose cotransporter in marine organisms
Authors: Morrison‐Shetlar Alison I.
Published: June 2005

A phylogenetic comparison of the structural and functional properties of the sodium‐D‐glucose cotransporter from a variety of marine species is presented. Found in the apical membrane of epithelial cells of kidney and intestine, this transport protein mediates the uphill movement of glucose coupled to the downhill movement of sodium ions. Monoclonal antibodies to the rabbit cotransporter react with a 78,000 Da protein in renal brush border membranes from skate, dogfish, and flounder, but not toadfish (which lacks functional expression of the cotransporter). Amplification of cotransporter DNA sequences by the polymerase chain reaction correlates well with the antibody results. Additional molecular studies of the sodium‐D‐glucose cotransporter promise to elucidate further the structure‐function relationship, particularly with respect to species‐specific stoichio‐metries. © 1993 Wiley‐Liss, Inc.
Effects of growth rate, temperature, season, and body size on glycolytic enzyme activities in the white muscle of atlantic cod (Gadus morhua)
Authors: Pelletier Dany , Guderley Helga , Dutil Jean‐Denis
Published: June 2005

In the fast‐growing Atlantic cod (Gadus morhua), the specific activities of the glycolytic enzymes phosphofructokinase (PFK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) in white muscle were positively correlated with growth rate. For PFK and PK, season modified the relationship between growth rate and enzyme activity. This effect may be due to differences in the initial condition of the fish used for the experiments in the different seasons. Acclimation temperature only affected the activity of LDH, but its effect was slight compared to that of growth rate and season. No relationship was found between glycolytic enzyme activities in white muscle and body size of wild cod ranging from 20 to 80 cm in length. These relationships suggest that in their natural habitat, cod are opportunistic feeders which increase the metabolic capacities of their muscles once food becomes available. © 1993 Wiley‐Liss, Inc.
Melatonin‐induced desensitization in amphibian melanophores
Authors: Rollag Mark D. , Lynch G. Robert
Published: June 2005

Video‐microscopic examination of pigment granule translocation in cultured amphibian melanophores provides continuous, real‐time observation of cellular responses to hormonal and pharmacologic agents and is particularly useful for studying the mechanisms underlying melatonin‐induced pigment aggregation. We have used such video‐microscopic technology to show that pigment cells become refractory to prolonged melatonin treatment and that the speed at which the desensitized condition becomes evident is dependent upon the countervailing concentration of antagonistic hormone, alpha‐melanocyte stimulating hormone (MSH). When melanophores were treated with 10 nM melatonin, desensitization occurred within 30 minutes in the presence of 5 ng/ml MSH, whereas five hours of melatonin treatment was required before the desensitized state was observed in the presence of 1 ng/ml MSH. The persistence of desensitization after melatonin removal depends upon the duration of initial melatonin exposure. When melanophores were treated with melatonin (10 nM) in the presence of 10 ng/ml MSH for two hours, the desensitized condition lasted less than 30 minutes; if the initial melatonin treatment was increased to four hours, however, the melanophores remained in the desensitized state for more than two hours after the melatonin was removed from the medium. During the course of these treatments, there was no substantial degradation of melatonin activity; i.e., a second population of melanophores responded normally to the melatonin‐containing media overlying desensitized melanophores. © 1993 Wiley‐Liss, Inc.
Stage‐related production of 21‐hydroxylated progestins by the dogfish (Squalus acanthias) testis
Authors: Barry Terence P. , Thomas Peter , Callard Gloria V.
Published: June 2005

Using shark (Squalus acanthias) testicular microsomes and [3H]progesterone ([3H]P) and [3H]17α‐hydroxyprogesterone ([3H]17α‐P) and [3H]17α‐hydroxyprogesterone ([3H]17α‐P) as substrates, two major products of 21‐hydroxylase action were identified; respectively, 21‐hydroxy‐4‐pregnen‐3‐one (11‐deoxycorticosterone, DOC) and 17α,21‐dihydroxy‐4‐pregnen‐3‐one (11‐deoxycortisol, S). Additional products of 17α‐hydroxylase/C‐17,20‐lyase action were detected: 17α‐hydroxyprogesterone (17αP), testosterone (T), and androstene‐dione (AE). When microsomes derived from tissues in premeiotic (PrM), meiotic (M), and postmeiotic (PoM) stages of spermatogenesis were compared, maturation‐related increases were observed with both 21‐hydroxylase (3‐ to 20‐fold) and 17 α‐hydroxylase (2‐ to 6‐fold). With [3H]P as tracer, the half‐maximal substrate concentrations (Km = 0.2–1.0 μM) and maximal reaction velocities (Vmax = 9–25 pmol/mg protein/min) were similar for both enzymes when assayed in the same preparation, suggesting they compete for available substrate. Also, the presence of 1‐ or 10‐fold molar excess radioinert DOC reduced conversion of [3H]P to 17α‐hydroxylated products. [3H]DOC itself was a substrate of 17α‐hydroxylation but not C‐17,20‐lyase action. Expression of 21‐hydroxylase and 17α‐hydroxylase activities in cultured spermatocysts (intact germ cell/Sertoli cell units) was confirmed by detection of immunoreactive 17α,20β,21‐trihydroxy‐4‐pregnen‐3‐one (20β‐S), S, 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17α,20β‐P), DOC, P and T in spent media. 20β‐S and S secretion increased and 17α,20β‐P decreased progressively with stage of maturation, but DOC was similar in all stages. P secretion was maximal and T lowest in M‐stage spermatocysts, but when DOC (0.1 μM) was added to PrM or PoM spermatocysts, T output decreased. Taken together, the data suggest that 21‐hydroxylating pathways, via direct and indirect mechanisms, affect accumulation of bioactive steroids (P and T) differentially by stage of spermatogenic development. Whether 21‐hydroxylated progestins produced in shark testis have paracrine or endocrine actions in their own right remains to be investigated. © 1993 Wiley‐Liss, Inc.
Similar responses to pharmacological agents of 1,2‐OAG–induced compaction‐like adhesion of two‐cell mouse embryo to physiological compaction
Authors: Ohsugi Mami , Ohsawa Takuro , Semba Reiji
Published: June 2005

A comparison was made of responses to pharmacological agents between cell adhesion induced by an activator of Ca2+‐phospholipid‐dependent protein kinase (PKC) and physiological compaction in mouse embryos. An activator of PKC, 1‐oleoyl‐2‐acetyl‐sn‐glycerol (1,2‐OAG) induced the compaction‐like adhesion of cells in two‐cell embryos within 5–10 min and the adhesion lasted during the course of treatment for 1 h. W‐7 and W‐5 (calmodulin antagonists) and cytochalasin B and cytochalasin D (inhibitors of the polymerization of microfilaments) each completely interfered with the 1,2‐OAG–induced adhesion of cells. Two‐cell embryos having once shown evidence of cell adhesion in response to 1,2‐OAG were decompacted when they were transferred to a medium that contained 1,2‐OAG and any one of the agents described above. Colchicine and colcemid (inhibitors of the polymerization of microtubules) and tunicamycin (an inhibitor of N‐linked protein glycosylation) each had no effect on the 1,2‐OAG–induced adhesion of cells. In Ca2+ ‐free medium, treatment with 1,2‐OAG failed to induce any cell adhesion. These results are very similar to those reported for physiological compaction at the late eight‐cell stage. Thus, the compaction‐like adhesion of cells in mouse embryos at the two‐cell stage appears to be a calmodulin‐dependent process, requiring assembled microfilaments and extracellular Ca2+ ions but not microtubules or N‐linked glycoproteins as is the case for the physiological compaction. © 1993 Wiley‐Liss, Inc.
Cloning and chromosomal mapping of mouse seminal vesicle protein F
Authors: Yoo‐Warren Heeja , Willse Ann Gore , Hull Jacqueline , Brownell Elise
Published: June 2005

Seminal vesicle proteins (SVPs) are made by male rodents, and form the copulatory plug following mating. Here we report a partial nucleotide sequence of a mouse clone homologous to rat SVP F. Unexpectedly, we found that SVP F‐related transcripts are expressed at high levels in mouse skeletal muscle. We mapped mouse SVP F to mouse chromosome 15 using somatic cell hybrid lines. © 1993 Wiley‐Liss, Inc.
Modulatory effects of adenosine on Porichthys luminescence
Authors: Mallefet J. , Baguet F. , Fauville C.
Published: June 2005

The modulatory effects of exogenous applications of adenosine on luminous organs (photophores) of the fish Porichthys were studied. Pretreatment of photophores with adenosine (10−7 to 10−3 M) potentiated both phases of adrenaline induced luminescence. The first peak of light (Lmax1) showed a 3‐fold increase following 10−7 M adenosine treatment; a maximal increase of 12‐fold was observed with 10−3 M adenosine. The second peak of light (Lmax2) exhibited a similar dose‐response curve, but the maximal increase was attained with 10−4 M adenosine. The potentiating effect of 1 uM adenosine on light emission triggered by adrenaline increased for adrenaline concentrations ranging from 10−7 to 10−4 M for Lmax1, but it remained stable for Lmax2. All 4 P1‐purinergic agonists tested at the final concentration of 10−4 M induced a potentiation of adrenaline luminescence with the following rank of potency: L‐PIA > NECA > CADO ≥ CHA = ADO for Lmax1 and NECA > CADO > ADO > CHA > L‐PIA for Lmax2. The potentiating effect of adenosine was antagonized with the following rank of potency by the P‐1 purinergic antagonists: CPT > DPMX ≥ AMINO > THEO for Lmax1 and CPT > AMINO > THEO ≥ DPMX for Lmax2. According to the classification of purinergic receptors, our results suggest that P1‐purinergic receptors might be implicated in the adenosine potentiation of Porichthys adrenaline luminescence. Experiments also showed that nor‐adrenaline luminescence is inhibited by 1 uM adenosine pretreatment. Further work will be necessary to elucidate the mechanism involved in the modulatory roles played by the purinergic receptors on adrenaline and noradrenaline luminescence in Porichthys photophores. © 1993 Wiley‐Liss, Inc.
Extent of mosaicism in experimentally produced diploid/triploid chimeric trout
Authors: Nilsson Eric E. , Cloud J. G.
Published: June 2005

Chimeric rainbow trout embryos have been produced by injecting isolated blastomeres into intact recipient blastulae. In order for chimeric fish to be useful in studies of development, it is necessary to determine whether the various organs or tissues of the resultant chimera have an equal probability of arising from the injected cells derived from donor embryos. The objective of this investigation is to determine the proportion of cells in the blood, liver, and brain tissues of rainbow trout chimeras that are derived from the injected cells. Blastomeres isolated from normal diploid blastulae were microinjected into age‐matched triploid recipient embryos, and the treated embryos grown until 4 weeks post hatch. Samples of blood, liver, and brain tissues were dispersed; the cell nuclei were labeled with propidium iodide, and the samples subjected to flow cytometric analysis to determine the proportions of diploid and triploid nuclei. The proportion of cells that were diploid varied among the resultant chimeric trout. Analysis of variance on the proportion of diploid cells in each sample indicated that there was no significant effect of tissue type. These results support the hypothesis that the isolated cells of the donor embryo are no more likely to colonize one tissue or organ type of a chimera than another. © 1993 Wiley‐Liss, Inc.