bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative aspects of estrus synchronization, ovulation induction, and embryo cryopreservation in the scimitar‐horned oryx, bongo, eland, and greater kudu
Authors: Schiewe Mitchel C. , Bush Mitchell , Phillips Lyndsay G. , Citino Scott , Wildt David E. 
Published: June 2005

AbstractComparative studies were conducted to evaluate the efficacy of estrus synchronization, ovulation induction, nonsurgical embryo collection, and cryopreservatin procedures in the scimitar‐horned oryx (Oryx dammah), bongo (Tragelaphus euryceros), eland (Taurotragus oryx), and greater kudu (Tragelaphus strepsiceros). In the scimitar‐horned oryx, a 6α‐methyl‐17α‐acetoxyprogesterone (MAP) pessary vs. prostaglandin F2α (PGF2α) estrus synchronization treatment was compared; only PGF2α was tested in the other species. Ovarian responsiveness to follicestimulating hormone (FSH‐P, b.i.d. for 5 days) or pregnant mare's serum gonadotropin (PMSG, single injection) was evaluated in all species. MAP and PGF2α were equally effective (P < 0.05) for synchronizing estrus in scimitar‐horned oryx. Signs of estrus, including mounting, were observed in 15 of 33 (45.4%) oryx donors, but copulation was observed on only 8 occasions. Mean number of CL/ovulating bongo and eland female was enhanced (P < 0.05) by FSH‐P compared to PMSG (4.5 ± 1.8 vs. 1.3 ± 0.3 CL/bongo and 10.6 ± 4.6 vs. 1.0 ± 0.6 CL/eland, respectively) treatment. The difference in mean (± SEM) CL number between FSH‐P‐ and PMSG‐treated oryx donors approached significance (4.6 ± 1.6 vs. 2.7 ± 0.8, respectively; P = 0.08). Embryos and ova were recovered nonsurgically from 10 of 19 (52.6%) of the ovulating oryx, 9 of 10 (90%) bongo, 6 of 10 (60%) eland, and both (100%) greater kudu. A high proportion (60%) of cryopreserved oryx embryos maintained an excellent‐or good‐quality grade (QG) after thawing. A higher proportion (P < 0.05) of embryos frozen in 1.5 M dimethyl sulfoxide (6 of 10) or 1.5 M glycerol (6 of 10) solutions maintained their prefreeze QG compared to the propylene glycol counterparts (3 of 10). The transfer of thawed embryos to synchronized oryx recipients (n = 9) resulted in no pregnancies. Conventional techniques for synchronizing ovarian activity, inducing ovulation, and flushing the uterine content of farm livestock largely are adaptive to these African antelope species. However, the overall efficiency of these strategies for consistently promoting superovulation and large numbers of embryos is relatively low. For these species, the primary limitations to effective embryo recovery and transfer appear to be: 1) a lack of estrous behavior which contributes to a low incidence of mating and, thus, poor fertilization and recipient synchrony, and 2) a resilience of the ovaries to conventional gonadotropic preparations.
In vitro fertilization of lobster oocytes
Authors: Talbot P. , Poolsanguan W. , Poolsanguan B. , Al‐Hajj H. 
Published: June 2005

AbstractThe feasibility of fertilizing preovulatory lobster oocytes was examined in vitro under various experimental conditions. Large (1.6 mm diameter) and small (0.6 mm diameter) oocytes were compared in fertilization trials. Small oocytes were surrounded by thin envelope thought to correspond to envelope 1A of mature oocytes. Large oocytes were surrounded by a fully formed vitelline envelope comprised of two distinct sublayers, 1A and 1B. Although sperm bound very effectively to the coat surrounding small oocytes, none penetrated the coat or fertilized the oocytes. Large diameter oocytes that were removed from follicles by dissection were fertilized by sperm from the proximal vas deferens of males and by sperm from the seminal receptacle of females. Fertilized oocytes showed a high degree of polyspermy. Higher numbers of sperm bound to, penetrated, and fertilized large diameter oocytes when inseminations were done in a saline solution (2.5LSH) than when done in artificial sea water (ASW). Sperm failed to bind to large diameter oocytes that were induced to ovulate in vitro by collagenase treatment. Contaminating enzymes may have destroyed the sperm receptor in envelope 1A of collagenase treated oocytes. Our in vitro fertilization method will allow the process of fertilization to be studied experimentally in lobsters, and it may be applicable to other decapods.
Modulation of the human sperm acrosome reaction by effectors of the adenylate cyclase/cyclic AMP second‐messenger pathway
Authors: De Jonge C. J. , Han H.‐L. , Lawrie H. , Mack S. R. , Zaneveld L. J. D. 
Published: June 2005

AbstractThe acrosome reaction of spermatozoa appears to be analogous to various somatic cell exocytotic events which involve cascade reactions, i.e., transmission of an external signal across the cell membrane resulting in activation of an “amplifier” enzyme and the generation of a second messenger. Using a synchronous acrosome reaction system (De Jonge et al., J. Androl., 10:232–239, ′89a), it was found that analogues of the second‐messenger cAMP, dibutyryl cAMP (dbcAMP) and 8‐bromo cAMP, stimulated the acrosome reaction of capacitated spermatozoa. Additionally, treatment of spermatozoa with either xanthine or non‐xanthine phosphodiesterase inhibitors induced a significant (P < 0.05) increase in the percent acrosome reaction after a period of capacitation in comparison to untreated controls. These results indicate that analogues of cAMP or inhibitors which prevent cAMP hydrolysis can induce the human sperm acrosome reaction. Subsequent experiments were conducted to test whether the amplifier enzyme in the cascade reaction, adenylate cyclase, has a role in the acrosome reaction. Forskolin, an adenylate cyclase stimulator, caused a significant (P < 0.01) increase in the percent acrosome reaction in comparison to controls. Modulators of adenylate cyclase—adenosine, 2′‐0‐methyladenosine, and 2′,3′‐dideoxyadenosine—significantly (P < 0.01) inhibited the forskolin‐induced acrosome reaction. dbcAMP was able to overcome the inhibition by adenosine. Two inhibitors of protein kinase A, the Walsh inhibitor and H‐8, caused'a significant (P < 0.01) inhibition of the dbcAMP‐induced acrosome reaction. Finally, in the absence of extracellular calcium, dbcAMP induced a significant (P < 0.01) increase in the acrosome reaction in contrast to A23187. These results suggest that: 1) a molecular mechanism for the human sperm acrosome reaction involves the cAMP second‐messenger system; i.e., activation of adenylate cyclase, the amplifier enzyme that produces cAMP, production of cAMP as a second messenger, and activation of cAMP‐dependent kinase A; and that 2) activation of adenylate cyclase occurs after calcium influx.
Anatomic and enzymatic responses of the three‐spined stickleback, Gasterosteus aculeatus to thermal acclimation and acclimatization
Authors: Vézina Daphné , Guderley Helga 
Published: June 2005

AbstractThe three‐spined stickleback (Gasterosteus aculeatus) from the St. Lawrence Estuary prefers temperatures between 9 and 12°C, but encounters temperatures ranging from 0 to 30°C. To determine whether despite this preference for cool temperatures this species retains a capacity for metabolic compensation during thermal acclimation, adult sticklebacks were acclimated to 4°C and 20°C for 6 weeks at various ration levels. When food rations were maximal, PFK, CPT, and CS activities were twofold higher in cold‐acclimated sticklebacks, particularly in the pectoral muscle. This pattern of thermal compensation is similar to that shown by eurythermal fish with considerably higher thermal optima. However, at sub‐maximal rations, warm‐acclimated sticklebacks can undergo a decline in condition which confounds the compensatory response. In the field, even though food is abundant, the condition of male sticklebacks also declined as temperatures rose. When the condition factor declined by 30%, the pectoral and axial muscle indices decreased by 40% and 55%, respectively, and the activities of glycolytic and oxidative enzymes in the pectoral and axial muscles dropped by up to 60%. Clearly, a temperature‐induced increase in metabolic rate can confound a compensatory response to temperature.
Goblet cell alkaline phosphatase in silkworm midgut epithelium: Its entity and role as an ATPase
Authors: Azuma Masaaki , Takeda Susumu , Yamamoto Hiroshi , Endo Yasuhisa , Eguchi Masaharu 
Published: June 2005

AbstractThe characteristics of two alkaline phosphatases (ALP) in the midgut epithelium of the silkworm Bombyx mori (Insecta: Bombycidae) have been investigated further. Distributions of the soluble ALP and membrane‐bound ALP were determined quantitatively by rocket immuno‐electrophoresis with monospecific antibody against the purified soluble ALP and membrane‐bound ALP, respectively. More than 70% of soluble ALP was distributed in the posterior midgut, and the rest of it in the anterior and middle midguts. The membrane‐bound ALP existed at similar levels in all regions of midgut except the most anterior portion. Enzyme‐histochemistry of ALPs could be detected at the apical cell surface of goblet and columnar cells as shown in the previous paper on the immunohistochemistry of ALPs (Azuma, M., and M. Eguchi (1989) J. Exp. Zool. 251:108–112). Furthermore, it was shown that the soluble ALP (goblet cell ALP) required Mg2+ to express its maximum activity, but the membrane‐bound ALP (columnar cell ALP) was insensitive to Mg2+. By using ATP as the substrate, the purified soluble ALP possessed ATPase action with Mg2+ ‐ and/or HCO‐dependent manner. From these results, it is concluded that the soluble ALP functions as one of the ATPase at the goblet cell surface, differing from the K+‐ATPase. This ATPase may be a possible component in generating the alkalinization of midgut lumen characteristic of lepidopteran insects.
Behavioral thermoregulation of the toad, Bufo marinus: Effects of air humidity
Authors: Malvin Gary M. , Wood Stephen C. 
Published: June 2005

AbstractTwo experiments were performed. The first tested the hypothesis that the toad, Bufo marinus, will select a lower ambient temperature under dry environmental conditions. This behavioral response would reduce evaporative water loss and facilitate survival on land. The second experiment measured the effects of temperature on evaporative water loss. In the first experiment, toads were placed in a thermal gradient (11–40°C) for 3 days. On days 1 and 3, water‐filled dishes were placed along the temperature gradient and humid air was circulated through the chamber. On day 2, water dishes were removed, and dry air was circulated through the chamber. Body temperature (Tb) was recorded with a cloacal thermistor. Selected Tb was approximately 8.6°C lower during the dry conditions than during the humid conditions. The behavioral hypothermia took about 6 h to develop. In the second experiment, a reduction in Tb from 17.7 to 12.°C reduced evaporative water loss by 42%. Consequently, behavioral hypothermia of the toad is an important adaptation to dry environmental conditions.
Evidence of luminous bacterial symbionts in the light organs of myctophid and stomiiform fishes
Authors: Foran David 
Published: June 2005

AbstractThe myctophids and stomiiforms represent two common groups of luminous fishes, but the source of luminescence in these animals has remained undetermined. In this study, labeled luciferase gene fragments from luminous marine bacteria were used to probe DNA isolated from specific fish tissues. A positive signal was obtained from skin DNA in all luminous fishes examined, whereas muscle DNA gave a weaker signal and brain DNA was negative. This observation is consistent with luminous bacteria acting as the light source in myctophids and stomiiforms and argues against the genes necessary for luminescence residing on the fish chromosomes. To confirm the location of this signal, a bacterial probe was hybridized in situ to sections of a stomiiform. A strong signal was generated directly over specific regions of the fish light organs, whereas no signal was found over other internal or epidermal tissues of the fish. Taken together, these data provide the first indication that luminous bacterial symbionts exist in myctophids and stomiiforms and that these symbionts account for luminescence in these fishes.
Comparative studies of fish, amphibian, and reptilian vitellogenins
Authors: Carnevali Oliana , Belvedere Paola 
Published: June 2005

AbstractPlasma vitellogenins (VTGs) from estrogen‐treated males of the common carp Cyprinus carpio, common frog Rana esculenta, crested newt Triturus carnifex, and lizard Podarcis sicula were purified by MgCl2‐EDTA precipitation, DEAE cellulose chromatography, and ionexhange FPLC. VTG isoelectric points and molecular weights of VTG subunits were determined by chromatofocusing and SDS‐PAGE, respectively.Immune cross‐reactivity was examined by ELISA with homologous and heterologous anti‐VTG sera which were tested before and after purification by affinity chromatography with Sepharose‐bound heterologous VTGs.Amphibian and reptilian VTGs contained both common and species specific antigenic determinant, whereas carp VTG was immunologically distinct and formed by subunits with smaller mass as compared to the monomeric VTGs of the other three species.The three‐dimensional structure of VTG does not appear to be conserved during vertebrate evolution, probably because of differences in post‐translational processing.
A mechanism for the action of pregnant mare serum gonadotropin on aromatase activity in the ovarian follicle of the medaka, Oryzias latipes
Authors: Nagahama Yoshitaka , Matsuhisa Arito , Iwamatsu Takashi , Sakai Noriyoshi , Fukada Sachiko 
Published: June 2005

AbstractOur recent studies (Sakai et al., '88) have shown that there is a progressive increase in aromatase activity, assessed indirectly by the conversion of exogenous testosterone to estradiol‐17β, in medaka (Oryzias latipes) vitellogenic follicles isolated between 28 and 20 hr before spawning. The present study was designed to determine if pregnant mare serum gonadotropin (PMS) and cAMP are able to induce aromatase activity in early vitellogenic follicles isolated at 32 hr before spawning. Both 100 IU/ml PMS and 100 ng/ml testosterone alone significantly stimulated estradiol‐17β production by follicles at this stage. PMS also enhanced testosterone‐induced estradiol‐17β production. This enhancing effect of PMS on aromatization of exogenous testosterone to estradiol‐17β was completely inhibited by 10 μg/ml actinomycin D and 10 μ/ml cycloheximide. Both 5 mM dibutyryl cAMP (dbcAMP) and 10 μM forskolin, an adenylate cyclase activator, alone significantly stimulated estradiol‐17β production. A 1 μg/ml dose of cyanoketone, a potent inhibitor of 3β‐hydroxysteroid dehydrogenase, completely suppressed PMS‐ and forskolin‐induced estradiol‐17β production in the absence of testosterone, but did not influence the enhancing effect of either PMS or forskolin on the conversion of exogenous testosterone to estradiol‐17β. These results indicate that PMS induces aromatase activity in medaka vitellogenic follicles via an adenylate cyclase‐cAMP system, and further suggest that this action of PMS is dependent upon both transcriptional and translational processes.
Neither retinal nor pineal photoreceptors mediate photoperiodic control of seasonal reproduction in American tree sparrows (Spizella arborea)
Authors: Wilson Fred E. 
Published: June 2005

AbstractUsing sighted (SIG) and bilaterally enucleated (BOE) female tree sparrows, SIG, BOE, pinealectomized (SIG‐PX), and bilaterally enucleated‐pinealectomized (BOE‐PX) male tree sparrows, and intact and castrated male tree sparrows implanted epicranially with continuously emitting light sources or nonemitting blanks, I tested the hypothesis that extraretinal, extrapineal encephalic photoreceptors mediate photoperiodic control of seasonal reproduction in American tree sparrows (Spizella arborea). SIG females and BOE females displayed similar patterns of plasma luteinizing hormone (LH) responses to a photoregimen designed to induce LH secretion and later photorefractoriness, to restore photosensitivity, and to reinitiate the photosexual reflex. The testicular length profiles for SIG males, BOE males, SIG‐PX males, and BOE‐PX males likewise revealed similar patterns of responses (i.e., testicular growth, regression, photorefractoriness, and recovery of photosensitivity) to an essentially identical photoregimen. These data show, for the first time in an obligately photoperiodic species, that a simulated annual reproductive cycle can be generated in the absence of both the eyes and the pineal gland and argue that neither retinal nor pineal photoreceptors are obligatorily linked to the neuroendocrine mechanism that controls seasonal reproduction. When evaluated within the context of the failure of bilateral ocular enucleation and pinealectomy to disrupt seasonal reproduction, the observations that continuously emitting light sources implanted atop the skull induced testicular growth and later photorefractoriness in intact males, induced LH secretion and later photorefractoriness in castrated males, and blocked recovery of photosensitivity in photorefractory males make a compelling case for extraretinal, extrapineal encephalic photoreception in the mechanism that controls seasonal reproduction in tree sparrows.
Neuropeptide schistosomin inhibits hormonally‐induced ovulation in the freshwater snail Lymnaea stagnalis
Authors: Hordijk Peter L. , van Loenhout Harry , Ebberink Rob H. M. , de Jong‐Brink Marijke , Joosse Joos 
Published: June 2005

AbstractThis study examines the interaction between the caudodorsal cell hormone (CDCH) and schistosomin, a peptide secreted by the central nervous system of the snail (Lymnaea stagnalis) infected with the avain schistosome Trichobilharzia ocellata. Non‐infected snails were injected with synthetic as well as native CDCH in the absence or presence of purified schistosomin. The response to 2 pmol of synthetic CDCH was blocked for 90% by coinjection with 3.5 pmol of schistosomin. The ovulation‐inducing activity of extracts of cerebral commissures (the storage area of native CDCH) was also blocked by schistosomin. The degree of inhibition (65%), however, was less than that observed with synthetic CDCH. These results show that schistosomin inhibits ovulation and egg laying in Lymnaea. This explains the decrease or absence of egg laying in schistosome‐infected freshwater snails.
Concentration of gonadotropin‐releasing hormone in the brain during metamorphosis in the lamprey, Petromyzon marinus
Authors: Youson John H. , Sower Stacia A. 
Published: June 2005

AbstractThe concentration of lamprey gonadotropin‐releasing hormone (lamprey GnRH) and relative amounts of a second GnRH‐like form from brains of larvae (ammocoetes) and individuals during the seven stages of lamprey metamorphosis were measured using a lamprey GnRH radioimmunoassay following elution on a reverse‐phase high performance liquid chromatography (HPLC) system. Lamprey GnRH was not detectable in ammocoetes and was present in small quantities in only a few samples of metamorphosing individuals in stages 1–5 (0.475–0.667 ng/brain) but was more conspicuous at stage 6 (0.873 ± 0.308) and had increased significantly (7.8 ± 0.371) by the final stage (7). The second, GnRH‐like hormone eluted at a different time on HPLC compared to lamprey GnRH and was detected by the lamprey GnRH antiserum. This second GnRH‐like hormone appeared at stage 4 and was present, at a progressively increased relative concentration, in almost all samples to the end of metamorphosis where the level of 5.15 ± 0.625 ng/brain was significantly lower than that of lamprey GnRH. The brain weight increased by the final two stages but concentration of the two hormones/brain sample weight revealed, for both hormones, a trend of increased levels as metamorphosis progressed and significant differences in concentration between stages 6 and 7. The timing of increased concentration of GnRH in the brain of metamorphosing lampreys is discussed with reference to the acceleration of gonad maturation during and immediately after metamorphosis.
Oocyte and zygote zona pellucida lectin binding in BALB/cBy and C57BL/6By mice and their F1 hybrids
Authors: Legge Michael 
Published: June 2005

AbstractZona pellucida intact oocytes and zygotes from two inbred strains of mice (BALB/cByEss and C57BL/6ByEss) and their F1 hybrids were reacted with a lectin panel (ConA, WGA, sWGA, PNA, UEA I, LTA, BSB4, DBA, PHA‐P, LPA, and LFA). No major differences were observed between groups of mice for the majority of the lectin binding patterns. However, oocytes from BALB/cByEss and the F1 (C57BL/6ByxBALB/cBy) gave identical binding patterns for PNA. Following fertilization BALB/cByEss and the F1 (C57BL/6ByxBALB/cBy) bound UEAI and LTA more strongly, but the other two groups of mice demonstrated identical weaker binding of UEAI and LTA. These results indicate the possible influence of the paternal genotype on zona pellucida formation.
Oxygen consumption in relation to sustained exercise and social stress in Arctic charr (Salvelinus alpinus L.)
Authors: Christiansen Jørgen Schou , Jørgensen Even H. , Jobling Malcolm 
Published: June 2005

AbstractRates of oxygen consumption were measured repeatedly in feeding groups of Arctic charr (Salvelinus alpinus L.) subjected to moderate sustained exercise or allowed to perform routine swimming activity (control). Oxygen consumption did not differ significantly between treatments. Agonistic activity, assessed in terms of bite mark frequencies, were significantly reduced in exercising fish. Consequently, high levels of spontaneous activity displayed by the control fish in performing agonistic interactions may have led to substantial increases in energetic costs resulting in energy expenditures equivalent to those shown by fish performing forced swimming at moderate speeds.Plasma cortisol levels measured at the end of the experiment suggested that both control and exercising fish were subjected to chronic stress with cortisol levels of exercising fish being significantly higher than those of controls. The validity of using plasma cortisol levels as an indicator of stress per se is discussed.
Reorganization of escape reflexes during asexual fission in an aquatic oligochaete, Dero digitata
Authors: Drewes Charles D. , Fourtner Charles R. 
Published: June 2005

AbstractAsexual reproduction in the aquatic oligochaete Dero digitata involves 1) formation of a mid‐body fission zone and transverse fission plane separating the worm into anterior and posterior zooids; 2) development of four new head segments in the posterior zooid, just behind the fission plane; and 3) development of new tail segments in the anterior zooid, just anterior to the fission plane. Electrophysiological recordings from normal (i.e., non‐fissioning) and prefission worms indicate similar proportioning of giant nerve fiber sensory fields; the medial (MGF) and lateral (LGF) giant fiber fields encompass the anterior‐most 30% and posterior‐most 70%, respectively, of the worm's length. Throughout prefission stages both MGF and LGF spikes were reliably through‐conducted, though at reduced velocity, across the fission zone. This agrees with anatomical results showing continuity and reduced diameter of MGF and LGF in the fission zone. Within seconds after fissioning, sensory fields in the rostral segments of posterior zooids (= 18% of zooid length) switch from LGF to MGF sensitivity. Further changes in giant fiber sensory fields and conduction velocities in the posterior zooid, during the next 7 days, lead to a functional organization of escape reflex pathways comparable to that in normal worms. Our results suggest that an escape reflex switching mechanism, along with strong modulatory influences, ensures appropriate and adaptively significant escape reflex functioning in posterior zooids both before and after fissioning.