bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro effects of insulin on macromolecular events in newt limb regeneration blastemata
Authors: Vethamany‐Globus S. , Globus M. , Darch A. , Milton G. , Tomlinson B. L.
Published: June 2005

This work provides data demonstrating a stimulatory effect of insulin on macromolecular events occurring in cultured regeneration blastemata and demonstrates a synergistic interdependence between nerves and insulin in newt limb regeneration. The current experiments provide evidence for the following: (1) Insulin is paramount for expression of the mitogenic effect of nerves on cultured blastemata. (2) Insulin stimulates the incorporation of (3H)uridine into the acid‐insoluble fraction of blastemal homogenates, but it does not alter the turnover rate of incorporated labeled uridine. (3) Insulin also stimulates the incorporation of 35SO4 and (3H)leucine into both chondroitinase‐sensitive and chondroitinase‐resistant blastemal proteoglycans. (4) Insulin increases the uptake of radiolabeled precursors by the blastemata, namely, (3H)leucine, (3H)uridine, 35SO4, (3H)α‐aminoisobutyrate, and (3H)2‐deoxy‐D‐glucose. The importance of insulin in the regulation of newt limb regeneration is discussed.
Inability of newt epidermal cells to migrate over concanavalin A‐coated substrates
Authors: Donaldson Donald J. , Mahan James T.
Published: June 2005

Pieces of coverslip glass coated with various proteins were implanted under one edge of a fresh skin wound on adult newt hind limbs so that the implant served as wound bed for migrating epidermal cells as they attempted to form a wound epithelium. Despite the fact that concanavalin A (Con A) receptors could be demonstrated on newt epidermal cells with fluorescein isothiocyanate (FITC)‐conjugated lectin, Con A‐coated implants supported practically no migration, an even poorer response than the modest amount of migration that occurred on uncoated glass. Coomassie blue staining verified that the lectin formed a complete film over the glass, and peroxidase binding assays showed that even after several hours in the wound, the Con A binding sites for mannose were still available. Migration on fibrinogen‐coated glass (a good migration substrate) was not affected by placing the implants next to Con A‐coated implants. Thus, the failure to migrate on Con A cannot be explained by soluble Con A effects from lectin leaching off the implants. These data suggest that linkages between cell surface mannose and the substrate are not part of the strategy by which newt epidermal cells migrate.
Endogenous peroxidase in the visceral endoderm of early mouse embryos
Authors: Bałakier Hanna
Published: June 2005

Endogenous peroxidase activity was demonstrated in early mouse embryos by means of the diaminobenzidine staining reaction. This enzyme was observed in visceral endoderm on the seventh to eighth day of gestation in vivo, but was no longer detected on the ninth day of development. In cell layers developing from blastocysts or isolated inner cell masses cultured for 96–144 h (developmental stage equivalent to 6–7.5‐day‐old embryos), diaminobenzidine product was also observed in visceral endodermal cells. Most of the endogenous peroxidase was localized inside or close to the numerous apical vacuoles in the endoderm. Ectoderm, mesoderm, ectoplacental cone, and trophoblast cells did not contain endogenous peroxidase.
The effects of products and inhibitors of arachidonic acid metabolism on the hamster sperm acrosome reaction
Authors: Meizel Stanley , Turner Kenneth O.
Published: June 2005

ABSTRACT The mammalian sperm acrosome reaction (AR) is a fusion and fenestration of sperm head membranes which is essential for fertilization. Our earlier work demonstrated that arachidonic acid could stimulate the AR 15 min after addition to hamster sperm capacitated by incubation for 4.5 h. The present study was undertaken to determine whether inhibitors of arachidonic acid metabolism could affect the stimulation of the AR by arachidonic acid and whether products of its metabolism could stimulate the AR. Phenidone or nordihydroguaiaretic acid, inhibitors of both the cyclo‐oxygenase and lipoxygenase pathways of arachidonic acid metabolism, and docosahexaenoic acid, a cylo‐oxygenase pathway inhibitor, inhibited the AR induced by arachidonic acid. PGE2, a product of the cyclo‐oxygenase pathway of arachidonic acid metabolism and 5‐ or 12‐hydroxyeicosatetraenoic acid (HETEs) products of the lipoxygenase pathway, stimulated the AR when added to sperm capacitated by incubation for 4.5 h. Prostaglandins not derived from arachidonic were also tested: PGE1 stimulated the AR, but PGF1α and PGA2 did not. We suggest that arachidonic acid metabolites produced by the sperm and by the female reproductive tract are important for the mammalian sperm AR.
A central action of octopamine on ventilation frequency in Corydalus cornutus
Authors: Bellah Karil L. , Fitch Greg K. , Kammer Ann E.
Published: June 2005

Application of octopamine (10−4 or 10−5 M) to ventrally dissected hellgrammites increased the frequency of the ventilatory rhythm 16.6 ± 2.0%. Similar results were observed when a chain of abdominal ganglia was isolated from other parts of the central nervous system and the periphery; thus, the effect was a central one. A ventilatory increase of similar magnitude was not elicited from chains of ganglia that lacked the dominant oscillator for the ventilatory rhythm; thus, exogenous octopamine acts at the expected site of physiological control of the rhythm. Dopamine (10−4 or 10−5 M) decreased ventilatory frequency 16.7 ± 4.0%. Thus, as in other animals (Livingstone et al., '80), a pair of amines has opposite effects on an invertebrate behavior.
Sodium balance in the American alligator
Authors: Ellis Tamir M. , Evans David H.
Published: June 2005

Alligators in fresh water regulate their plasma and cloacal fluid electrolytes at concentrations similar to those of other crocodilians. They have an exchangeable Na pool of 60.8 μmol/gm and a unidirectional Na efflux of 3.9 μmol/100 gm·hr. Of this 11% is excreted from the cloaca, 43% presumably diffuses across the body integument, and the remaining 46% is lost from the head region. The integumental Na efflux is estimated to be 0.01 μmol/cm2·hr. In fresh water the net flux is 0.5 μmol/100 gm·hr, which suggests that nondietary Na uptake can compensate for 86% of unidirectional Na loss.
A rapid procedure for visualising the inner cell mass and trophectoderm nuclei of mouse blastocysts in situ using polynucleotide‐specific fluorochromes
Authors: Handyside Alan H. , Hunter Susan
Published: June 2005

A rapid procedure has been devised to count the numbers of outer trophectoderm (TE) and inner cell mass (ICM) cells of mouse blastocysts by differentially labelling their nuclei in situ with polynucleotide‐specific fluorochromes. The TE nuclei were labelled with propidium iodide (PI) by permeabilising the cells using selective antibody‐mediated complement lysis (Solter and Knowles, '75). The blastocysts were then fixed in ethanol and the ICM nuclei labelled with bisbenzimide. These two fluorochromes have widely different fluorescent spectra. Thus, by using fluorescence microscopy with appropriate filter combinations, the PI‐labelled TE nuclei appeared pink or red; the bisbenzimide‐labelled ICM nuclei, blue or unlabelled.

The total numbers of blastocyst nuclei and the numbers of ICM nuclei counted by differential labelling were similar to the numbers detected after spreading the nuclei of intact blastocysts or immunosurgically isolated ICMs by air‐drying (Tarkowski '66).

Differential labelling of TE and ICM nuclei in situ has two important advantages—that the numbers of both these cell types can be determined for individual blastocysts and that spatial relationships are partially preserved so that regional interactions can be studied.
Evaporative water loss and skin lipids of anuran amphibians
Authors: Withers Philip C. , Hillman Stanley S. , Drewes Robert C.
Published: June 2005

African reed frogs (Hyperolius spp) and tree frogs (Chiromantis spp), an Australian tree frog (Litoria gracilenta) and a South American tree frog (Phyllomedusa azurae) have much lower rates of evaporative water loss from their dorsal skin (0.2 to 2 mg g−1 h−1) than most anuran amphibians, which evaporate water at a rate equivalent to a free water surface. Evaporative water loss rates of Chiromantis, Hyperolius, and Litoria are considerably higher when their ventral skin is exposed. Other anuran amphibians, Hylagratiosa, Agalychnis callidryas, and Afrixalus spp, appear to be moderately waterproof. The mechanism for reduction of evaporative water loss from the skin of the waterproof frogs is unclear, but it appears to involve a lipid barrier. This barrier is disrupted by treatment with a chloroform‐methanol mixture. Thin layer chromatographic analysis of lipids extracted from the dorsal and ventral skin of waterproof and nonwaterproof amphibians revealed a considerable variety of neutral and polar lipids. However, few of the lipid components were unique to the dorsal skin of waterproof frogs. We conclude that the presence per se of many of the intradermal lipids (including cholesterol, cholesterol esters, fatty acids, triglycerides, and phospholipids) is not correlated with a waterproofing barrier, although these lipids might contribute to a structural lipid barrier.
Photoperiodism in the lizard, Anolis carolinensis
Authors: Ferrell Blaine R.
Published: June 2005

A daily rhythm of testicular photosensitivity entrained by the photoperiod of 10L:14D (light:dark) was detected in lizards at 30°C but not at 20°C. Testicular development in anoles at 30°C was stimulated by a 1‐hour light interruption occurring 16.5 hours (Experiment I) or 20 (Experiment II) after the onset of the daily photoperiod. Light interruptions occurring at other times of night tested were not stimulatory. Photoperiodism in this reptile appears to involve circadian mechanisms similar to those that have been described for members of other vertebrate classes. The expression of physiological events regulated by these mechanisms is temperature dependent.
The CO2‐specific sensitivity of hemocyanin oxygen affinity in the decapod crustaceans
Authors: Burnett Louis E. , Infantino Robert L.
Published: June 2005

The CO2‐specific sensitivity of hemocyanin oxygen affinity and oxygen binding site cooperativity were investigated in five species of crabs. The hypothesis that CO2‐specific effects on hemocyanin are related to the molecular CO2 concentrations that occur naturally in crab hemolymph was tested in crabs that experience a variety of hemolymph CO2 pressures. Crab species were chosen from subtidal, intertidal, and semiterrestrial habitats. Hemolymph samples from each species were added to physiological salines buffered with 50 mM HEPES. O2 equilibrium curves were determined spectrophotometrically by gassing the hemolymph‐saline mixtures with different P at constant P and temperature. We found no CO2‐specific effects on oxygen equilibrium properties of hemocyanin in any species under the conditions investigated. It is concluded that molecular CO2 and bicarbonate ions are not important in directly modulating the oxygen equilibrium properties of crustacean hemocyanins.
Earthworm leukocyte interactions during early stages of graft rejection
Authors: Cooper Edwin L. , Roch Philippe
Published: June 2005

The earliest phase of graft rejection in earthworms, the recognition of foreign tissue antigens, has been subjected to analysis by confronting host leukocytes with foreign erythrocytes. Only rabbit and rat erythrocytes significantly prevented healing of allografts when grafts were transplanted and erythrocytes injected simultaneously. In contrast, autografts and allografts transplanted on worms injected 1 or 2 days before grafting were never affected. Since earthworms readily produce higher titers of erythrocyte agglutinins at 24 h postinjection than at later times, we propose a hypothetical scheme of earthworm leukocyte interactions that may occur during the early phases of graft healing and of agglutinin synthesis.
Hormonal regulation of development of the interrenal activity of Δ5‐3β‐hydroxysteroid dehydrogenase in bullfrog tadpoles
Authors: Hsu Chih‐Yun , Yu Nai‐Wen , Pi Chung‐Mio , Chen Schwu‐Jen , Ruan Chih‐Chuan
Published: June 2005

Since interrenal activity of Δ5‐3β‐hydroxysteroid dehydrogenase (Δ5‐3β‐HSD) in tadpoles during development follows the pattern of metamorphic progress (Hsu et al., '80) and Δ5‐3β‐HSD is a key enzyme in biosynthesis of corticosteroids, hypophysectomized (HX) tadpoles of Rana catesbeiana were injected with thyroxine (T4) or ACTH or T4 + ACTH. The untreated HX tadpoles served as controls. Interrenals of the four groups of tadpoles were prepared histochemically for assay of Δ5‐3β‐HSD activity. The reaction products in terms of absorbance were scanned under a defined area with a computerized microscope spectrophotometer. The results show that T4 or ACTH alone or T4 + ACTH together raised the enzyme activity above that of the controls significantly. The findings suggest an endogenous role of T4 and ACTH in development of this enzyme activity in tadpole interrenals.
Evidence for the involvement of a sperm trypsinlike enzyme in the membrane events of the hamster sperm acrosome reaction
Authors: Dravland J. Eric , Llanos Miguel N. , Munn Robert J. , Meizel Stanley
Published: June 2005

Previous studies from this laboratory have suggested a role for sperm trypsinlike activity in the membrane events of the hamster sperm acrosome reaction, but these conclusions have been disputed by studies done with guinea pig, mouse, and ram sperm. This study was designed to further investigate the role of such activity in the hamster sperm acrosome reaction. Washed hamster epididymal sperm were examined by electron microscopy after incubation in a defined medium. Fewer sperm incubated in the presence of the trypsin inhibitor benzamidine underwent the membrane events of the acrosome reaction compared to controls. Benzamidine did not interfere with the loss of the acrosomal contents in the sperm which did undergo acrosome reactions. The trypsin inhibitor NPGB (previously shown to inhibit the hamster acrosome reaction under other conditions) did not inhibit the membrane events or the loss of acrosomal contents when the acrosome reaction was induced by the fusogen lysophosphatidyl choline (a method of induction which may have bypassed the need for a trypsinlike enzyme). In a bioassay designed to measure acrosome reactions, fewer sperm preincubated with benzamidine subsequently penetrated zona‐pellucida‐free hamster eggs.

The present results together with those of an earlier study by this laboratory strongly suggest that a sperm trypsinlike enzyme has a direct or indirect role in the membrane events of hamster sperm acrosome reaction. The relationship of these results to studies with other species is discussed.
Reproductive development of female Schistosoma mansoni (Digenea: Schistosomatidae) following bisexual pairing of worms and worm segments
Authors: Popiel Irene , Basch Paul F.
Published: June 2005

Maturation and maintenance of normal reproductive function in female Schistosoma mansoni require a permanent association with the male, but the nature of this relationship is not well understood. The regional localization of a stimulatory factor in the male and its target in the female were investigated. Unisexual female and mature male worms were transected into segments of various lengths. Various combinations of transected male and female segments and intact worms were transferred to the mesenteric veins of recipient hamsters and were also maintained in vitro. In hamsters and in vitro, pairing took place between intact worms of each sex and segments of the other, and between segments of both sexes. The majority of female worms and segments so paired showed some reproductive development, as assessed by vitelline gland differentiation. In intact unisexual females paired with small male segments, vitelline gland development was limited to that portion of the worm that had been held by the male. Worm segments continued to display normal body contractions throughout 24 days of in vitro maintenance and morphological integrity was retained. It is concluded that 1) in the absence of a functioning gut, worm segments can survive for prolonged periods on nutrients absorbed through the tegument; 2) worm pairing, male stimulation, and the female developmental response are independent of central nervous control by the cerebral ganglia; 3) males have no centralized localization for the female‐stimulating factor; 4) vitelline gland differentiation in the female requires local stimulation through male contact, and this is not propagated throughout the worm.
Antagonistic effects of estradiol dipropionate and progesterone on the histology of the vagina and uterus of the mouse
Authors: Tripathi Ghanashyam
Published: June 2005

Administration of estradiol dipropionate (20 μg/day; 7 days) to ovariectomized mice caused heavy epithelial proliferation and intense cornification in the vagina and cellular as well as glandular proliferation in uterine tissues. Endometrial hypertrophy with cystlike appearance of uterine glands was seen in response to a long‐term (14 days) administration of estradiol dipropionate. Daily injection of progesterone (2 mg; 7 days) to ovariectomized mice resulted in desquamating mucosa, without any trace of vaginal cornification, and the presence of dense uterine connective tissue in the stromal region with typical uterine glands. However, treatment of estradiol depropionate in combination with progesterone at 1:100 dose ratio for 7 days produced vaginal histology similar to that in proestrus and uterine histology equivalent to the ovariectomized condition. The results revealed that progesterone antagonized the estrogenic effects and also that estradiol dipropionate antagonized the effects of progesterone. The effects of the two female sex steroids (estradiol dipropionate and progesterone) in vivo appeared to be more potent in the uterus than in the vagina.
On the role of fibronectin during the compaction stage of somitogenesis in the chick embryo
Authors: Lash James W. , Seitz Anna W. , Cheney Clarissa M. , Ostrovsky David
Published: June 2005

During the early stages of somitogenesis in the chick embryo the presomitic cells in the segmental plate undergo compaction. The aggregation of segmental plate cells is stimulated by fibronectin. The stimulation of segmental plate cells to aggregate and undergo compaction can be effected in isolated segmental plate cells, in isolated segmental plates, and in intact embryos removed from the yolk. The fact that the segmental plate cells react with greater vigor to cellular fibronectin than to plasma fibronectin suggests a specific molecular mechanism in the initiation of somitogenesis.
β‐Endorphins (β‐EP) in amphibians: Higher β‐EP levels during regenerating stages of anuran life cycle and immunocytochemical localization of β‐EP in regeneration blastemata
Authors: Vethamany‐Globus Swani , Globus Morton , Milton Guy
Published: June 2005

Plasma β‐endorphin (β‐EP) levels were measured at different stages of metamorphosis in anuran species, namely Rana catesbeiana, R. pipiens, and Xenopus laevis. The mean levels of β‐EP in tadpoles and postmetamorphic juveniles were significantly higher than adult levels in all three species examined. The pattern of high tadpole levels and low adult levels corresponds with the limb regeneration ability of the tadpole and restriction in the adult. We have also reported plasma β‐EP levels in two urodele species, Ambystoma tigrinum and A. jeffersonianum. Localization of β‐EP by immuno‐cytochemistry shows bright fluorescence to β‐EP antiserum in the wound epithelium of the regeneration blastema. The mesoderm and nuclei of all blastema cells remain nonreactive. It is suggested that receptors to β‐EP reside in the epidermis.
Regulation of the follicular hierarchy and ovulation
Authors: Bahr J. M. , Johnson A. L.
Published: June 2005

Studies are discussed which investigate the regulation of follicular maturation and the ovulation sequence of the domestic hen. The number of FSH receptors of ovarian granulosa cells decreases as the follicle matures, and this decrease in receptor number is paralleled by a gradual loss of FSH‐stimulable adenylyl cyclase (AC) activity. By contrast, LH‐stimulable AC activity increases as the follicle progresses through the hierarchy. In addition, FSH stimulates progesterone secretion by granulosa cells of the smaller preovulatory follicles, whereas these cells are only minimally responsive to LH. These data suggest that the maturation of less mature (smaller) follicles is primarily controlled by FSH, while LH may serve primarily as the ovulation‐inducing hormone. The ability of LH to stimulate progesterone release and induce premature ovulation is dependent upon the stage of the sequence. Injection of ovine LH 12 hr prior to ovulation of the first (C1) egg of the sequence induces fully potentiated prevulatory plasma progesterone surges and 100% premature ovulation, whereas injection prior to the second (C2) ovulation of the sequence fails to stimulate prolonged progesterone release and induces premature ovulation in less than 50% of injected hens. These results are consistent with data obtained in vitro which suggest that granulosa cells obtained 12 hr prior to a C1 ovulation secrete more progesterone in response to chicken LH compared to those obtained 12 hr prior to the C2 ovulation. These data are discussed in terms of the ovary's ability to act as a regulator of the ovulatory cycle.
Interrelationships between the hypothalamus, pituitary gland, ovary, adrenal gland, and the open period for LH release in the hen (Gallus domesticus)
Authors: Etches R. J. , Petitte J. N. , Anderson‐Langmuir C. E.
Published: June 2005

The asynchronous ovulatory cycle of the hen is believed to be the consequence of two interacting systems, one of which is circadian and regulates the timing of the preovulatory LH surge. In suport of this proposition, the open period for LH release was shown to oscillate with the same periodicity as the photoschedule when the hens were exposed to 14 L:7 D, 14 L:10 D, and 14 L:14 D. In addition, it was demonstrated that follicular maturation is not affected by or synchronized with the photoperiod. The physiological system that transduces the light/dark cycle into an open period for LH release has not been identified although circumstantial evidence supports the idea that the adrenal gland plays a role in this function. This evidence includes the anatomical juxtaposition of the left ovary and adrenal gland, innervation of steroid‐producing cells within the follicle by nerve tracts passing through the adrenal glands, the ability of injections of metyrapone to alter the timing of preovulatory LH release, the ability of injections of corticosterone to induce ovulation when a mature follicle is present in the ovary, and the ability of dexamethasone or infusions of corticosterone to block ovulation. Recently we have also shown that infusions of corticosterone will block the gonadotropic effect of PMSG, will inhibit the photoperiodic response, and do not affect the release of LH in response to injections of GnRH. The addition of corticosterone to incubations of dispersed granulosa cells does not affect their response to LH. These data suggest that corticosterone may modulate the responsiveness of the hypothalamus to tropic stimuli and demonstrate that exposure to corticosterone can alter the responsiveness of some ovarian tissues to gonadotropins.
Prior light alters the circadian clock in the chick pineal gland
Authors: Binkley Sue , Mosher Karen
Published: June 2005

N‐Acetyltransferase activity (NAT) exhibits a circadian rhythm in the pineal gland and retinas of chickens and is responsible for melatonin circadian rhythms. Chick pineal gland NAT was measured in vivo and/or in vitro after light‐dark cycles and after pretreatments with short photoperiod, long photoperiod, and constant light. Prior lighting changed the shape (phase, amplitude, and duration) of the rhythm in vivo. Some of the alterations are “programmed” into the pineal gland because they were observed in vitro in pineal glands from chicks similarly exposed to lighting pretreatments.
Circadian organization in Japanese quali
Authors: Underwood Herbert , Siopes Thomas
Published: June 2005

Our recent studies have implicated both the eyes and pinealas major components of the circadian system of Japanese quail. We assessed the role of these organs by examining the effect fo their removal on the circadian activity rhythm of quail exposed to either 24 hr light‐dark (LD) cycles or to continuous darkness (DD). Removal of only the pineal had no effect on the activity rhythm of quail in either LD or DD. Blinding (by orbital enucleation) had a major effect under both LD and DD. One third of the blinded birds showed entrainment under LD although entrainment patterns were very variable, whereas two thirds of blinded birds were arrhythimic. All blinded plus pinealectomized brids were arrhythmic in LD as were all blinded and blinded plus pinealectomized birds in DD. Accordingly, effects of pinealectomy can be seem only when pinealectomy is combined with blinding. The fact that blinding disrupts circadian organization in both LD and DD indicates that the eyes must act as major components of the quail's circadian system. In view of the postulated role for melatonin, an indoleamine, in circadian systems, the eyes, pineal, and blood of quail were assayed for this compound. Robust daily rhythms in melatonin content were observed in all three tissues. The blood rhythm is due to secretion of melatonin into the vascular system by both the pineal and eyes. The ocular melatonin rhythm continued after sectioning of the optic nerve, was reentrainable to a shift in the phase of the LD cycle, and persisted for at least 2 days in DD. These data suggest that the eyes play a major role within the circadian system and support the hypothesis that circadian pacemakers may reside within the eyes of quail. The results are discussed in view of the findings of others in both quail and other avian species. A general model for circadian organization in birds in presented in which the eyes, the pineal, and the suprachiasmatic nuclei of the hypothalamus comprise major elements of a multioscillator circadian system.
Photorefractoriness in European starlings: Associated hypothalamic changes and the involvement of thyroid hormones and prolactin
Authors: Nicholls T. J. , Goldsmith A. R. , Dawson A.
Published: June 2005

Responsivity to photostimulation in previously photorefractory European starlings is caused by subjection to short daylengths and is characterized by a marked activation of the hypothalamus in terms of synthesis of gonadotropin releasing hormone. This active hypothalamic state is amplified for a time by a subsequent exposure to long days but is soon completely reversed as the birds become photorefractory again. This latter effect of long photoperiods and the concurrent secretion of prolactin are dependent on the presence of thyroid hormones. Conceivably, prolactin causes photorefractoriness by inhibition at a hypothalamic level.
Photorefractoriness in Japanese quail: Possible involvement of the thyroid gland
Authors: Follett B. K. , Nicholls T. J.
Published: June 2005

Quail have a form of refractoriness to long daylengths that is relative and not absolute. The properties of “relative refractoriness” are compared with the more typical “absolute” form seen in starlings and the question is posed as to whether the two types represent the extremes of a single underlying process or are quite separate phenomena. A model is offered that assumes that a single process is involved, and some tests of the hypothesis, notably the involvement of the thyroid gland, are described.
Influence of weather on reproduction
Authors: Wingfield John C.
Published: June 2005

Laboratory investigations suggest that the effects of weather on avian reproduction could be manifest via a “stress” response resulting in an elevation of circulating levels of corticosterone and a depression of reproductive hormone secretion. However, field investigations indicate that additional endocrine responses also occur. Inclement weather early in the breeding season, i.e., before the nesting phase has begun, is generally not stressful in terms of plasma levels of corticosterone but does result in a delay of gonadal maturation and decreases in circulating levels of LH and sex steroid hormones. Conversely, storms that strike after the nesting phase has begun and when adults are feeding young do appear to be stressful, resulting in an increase in corticosterone and loss of body weight, but do not affect plasma levels of LH and sex steroid hormones. This latter fact is thought to be highly adaptive because the reproductive apparatus is maintained in a functional state so that renesting can begin immediately when environmental conditions improve. These data indicate that two endocrine mechanisms may be important for regulating responses to inclement weather under natural conditions.
Effects of polyamines upon capacitation and fertilization in the guinea pig
Authors: Fleming Alan D. , Armstrong David T.
Published: June 2005

The effects of polyamines upon the ability of guinea pig spermatozoa to undergo the acrosome reaction and upon sperm‐egg fusion were investigated. All of the polyamines (polyarginines and compound 48/80) stimulated the occurrence of the acrosome reaction, although differences in the duration of the preincubation period required were noted. The stimulatory effect of the polyarginines could not be reversed by washing, while that of 48/80 was abolished by its removal prior to induction of the acrosome reaction. Polyarginine‐treated spermatozoa were fully capable of fertilizing intact guinea pig eggs. In contrast, 48/80 completely blocked sperm‐egg fusion at only 5–10 μg/ml. This inhibition was reversible by washing either treated gamete. The ability of polyamines which may also be present at the time and site of fertilization, in vivo, to inhibit or stimulate gamete functions or interactions is discussed.
Role of soluble factors (gamones) and calcium ions in conjugation of the ciliate Euplotes patella syngen 2
Authors: Akada Rinji
Published: June 2005

Conjugation between cells of mating type IV and V in Euplotes patella syngen 2 was studied with respect to mating inducing factors (gamones) and their effects on pair formation. Type IV cells excreted into the medium gamone(s) of type IV which induced selfing pairs in and enhanced the gamone's excretion by cells of type V. The same effects on type IV cells were induced by cells and gamone(s) of type V. The number of homotypic pairs (IV‐IV, V‐V) increased with an increase in the level of Ca2+ in the medium. However, heterotypic pairs (IV‐V) were constantly formed even in the absence of Ca2+, and their formation was not influenced by the level of Ca2+. When cells of two types were mixed, heterotypic pairs were predominantly produced, although cells were capable of forming pairs between homotypic types. These results revealed that pair formation between heterotypic cells was different from that between homotypic cells in the requirement of Ca2+, and that the specificity of pair formation between heterotypic cells was more predominant than that of homotypic ones.
Peroxidase activity in the epithelium of the digestive tract of the bullfrog, Rana catesbeiana
Authors: Sugimoto Keiji , Ichikawa Yasuaki , Nakamura Itsuo
Published: June 2005

Peroxidase activity was examined cytochemically in the mucosal epithelium along the length of the digestive tract from the esophagus through the large intestine during the development of the bullfrog, Rana catesbeiana. In the tadpole of this species, cells with peroxidase activity were found abundantly in the esophagus, stomach, and large intestine; and the types of such cells differed according to the region: ciliated cells and mucous cells in the esophagus; ciliated cells in the stomach; and brush cells, absorptive cells, and goblet cells in the large intestine, respectively. After metamorphosis, however, peroxidase activity was observed exclusively in absorptive cells and goblet cells in the large intestine. Peroxidase activity was commonly demonstrated in apical vesicles or granules, to some degree in rough endoplasmic reticulum, and in some elements of the Golgi apparatus. Furthermore, reaction product was also found in mucus covering the luminal surface of such epithelial cells. These findings indicate that peroxidase‐positive cells, which may have the ability to synthesize peroxidase as a secretory product, were distributed mainly in three regions of the digestive tract in tadpoles (esophagus, stomach, and large intestine), but were centered in one specific region, the large intestine, after metamorphosis. Concomitantly, the variety of types of peroxidase‐positive cells decreased during metamorphosis. Our results indicate that some of the peroxidase in the digestive tract may have a secretory origin and may play a role in the defense against microorganisms.
Steroidal enhancement of growth in parasitic larvae of Ascaris suum: Validation of a bioassay
Authors: Fleming Michael W.
Published: June 2005

Third‐stage larvae of the swine parasitic roundworm, Ascaris suum, were grown in stationary multiwell cultures in the presence of synthetic steroid hormones or the HPLC fractions of a steroid extract of adult female reproductive tracts to determine the subsequent effect of these compounds on length of 4th‐stage larvae. Log doses of ecdysone, 20‐hydroxyecdysone, progesterone, and makisterone standards, from 50 pg/ml to 500 ng/ml, were incubated with larvae for 1 day in RPMI‐1640 supplemented with cholesterol. Length measurements were made on 4th‐stage larvae after an additional 6 days of incubation. All compounds and extracts had a dose‐dependent enhancement on length of these larvae; the partially purified extracts were more potent than their synthetic analogs. All standards and extracts except makisterone showed reduced or no response at higher dose levels. In contrast, makisterone continued to have maximal effect from 500 pg/ml to 500 ng/ml. Short exposure period to the steroid and low concentration were critical to demonstrate enhanced growth in this homologous bioassay.
Annual testicular cycle of the lizard Anolis carolinensis: Effects of pinealectomy and melatonin
Authors: Underwood Herbert
Published: June 2005

The effects of pinealectomy and exogenous melatonin treatment on the reproductive system of male anoles were examined at several different times of year. In September pinealectomy of anoles exposed to either a stimulatory LD 14:10 light cycle or a nonstimulatory LD 10:14 light cycle induced significant testicular growth and development over that observed in sham‐operated anoles. At a nonphotosensitive time of year (December) pinealectomy also had a significant progonadal effect but no effect of pinealectomy was seen in February‐March. Daily melatonin injections given either in the morning or afternoon (or both) failed to block gonadal growtheither (1) in sham‐operated or pinealectomized anoles exposed to LD 14:10 in the fall or (2) in pinealectomized lizards exposed to LD 10:14 in the fall. Continuous melatonin administration via subcutaneous silastic implants blocked the progonadal effects of pinealectomy in the winter (December).

The results show that (1) pinealectomy can have significant progonadal effects; (2) these effects are seasonal but can encompass phases of the annual testicular cycle which are either photoperiod‐dependent or temperature‐dependent; and (3) melatonin may be a reproductively active factor involved.
Influence of the uterine environment on rat sperm motility and swimming speed
Authors: Goeden Helen M. , Zenick Harold
Published: June 2005

The present study compared several rat sperm parameters in semen samples recovered from a natural uterine environment (i.e., intact estrous female) to those recovered from an artificially induced uterine environment (i.e., ovariectomized hormonally primed female). The sperm parameters measured were percent motile, percent exhibiting forward progressive motility, actual swimming speed, and linear swimming speed. The comparisons were conducted at four postcopulatory time points (0.25, 1.5, 3, and 6 hours) in order to detect differences as a function of residence time within the uterus. No significant differences (P<0.05) in the parameters were seen between the two types of uterine environments. Residence time within the reproductive tract had no significant effect on the parameters with the exception of percent motile, which was significantly increased (P<0.01) at the 1.5‐hour postcopulatory time point.
Effect of absorbed and nonabsorbed anti‐H‐2 antiserum on mouse blastocysts
Authors: Warner Carol M. , Ostlie Norma S. , Spannaus Donna J.
Published: June 2005

Conventional antisera and monoclonal antibodies have been used to demonstrate the presence of H‐2 antigens on preimplantation mouse embryos. In this study, the specificity of previously used anti‐H‐2 conventional antisera was tested by absorption of the antisera on spleen lymphocytes. It was found that absorption of the anti‐H‐2 antisera removed all of the antibody reactive with lymphocytes, but only about half of the antibody reactive with embryos. The effect of absorbed and nonabsorbed anti‐H‐2 antisera on mouse blastocysts was tested both by cytotoxicity assays and by electron microscopy. The results suggest that conventional antisera do indeed detect H‐2 antigens on mouse embryos, but they may detect other, as yet undefined, antigens as well.
An ovarian regression syndrome in the platyfish, Xiphophorus maculatus
Authors: Burns John R. , Kallman Klaus D.
Published: June 2005

The highly inbred Coatzacoalcos (Cp) strain of the platyfish, Xiphophorus maculatus, was noted for a high percentage of infertile females (XX). The ovaries of approximately one‐quarter of all females regress. The time of gonadal atrophy varied from before sexual maturation up to 11 months of age. The gonadotropic zone of the pituitary was hypertrophied in regressed females. Transplants of immature testes and ovarian tissue into the caudal musculature of regressed females and the subsequent maturation of the grafts demonstrated that the ovarian degeneration was not due to pituitary or hypothalamic malfunction or an autoimmune disease.

The cause of the gonadal degeneration was apparently localized to the ovary itself. This phenomenon was never observed in males (XY). Regressed ovaries fell into two categories, designated types I and II, with all being characterized by the presence of ductlike structures which resembled male efferent ducts, lined by Sertoli cells. Type I ovaries bore a marked similarity to certain mammalian dysgenetic gonads, while type II ovaries contained many proliferating germ cells and could be compared to the human neoplasm termed gonadoblastoma. It is suggested that the physiological lesion responsible for the ovarian regression syndrome involves the processes that control the determination and differentiation of the germ cells similar to those found in human 46,XY gonadal dysgenesis.
Size regulation of regenerated organs in the compound ascidian, Polyandrocarpa misakiensis
Authors: Taneda Yasuho
Published: June 2005

Fragments of zooids of the compound ascidian, Polyandrocarpa misakiensis, have the capacity for morphallactic regeneration. In untreated fragments of zooids, the sizes of regenerated organs were in proportion to the total sizes of the fragments. If two anterior fragments were fused together at their cut surfaces, double‐zooid monsters were produced, each regenerating the posterior part at the fusion area. Monsters, resulting from the fusion of two anterior fragments of different sizes, regenerated two digestive loops that were similar in size.
Development of sucrase in the chick small intestine
Authors: Matsushita Susumu
Published: June 2005

Development of sucrase in the chick small intestine was studied biochemically and immunologically using antiserum prepared against purified chick intestinal sucrase. Sucrase activity was first detectable at 10 days of incubation and increased with age. After a transient drop at 20 days, the activity rapidly increased to the adult level. Immunodiffusion and polyacrylamide gel electrophoretic studies suggested that the sucrase of the embryonic and hatched chick intestines was identical except for a difference in the content of sialic acids. In immunofluorescence and immunoelectron microscopy, sucrase was found to appear on the luminal surface of epithelial cells at 8–10 days of incubation, soon after the start of morphological differentiation from an undifferentiated thick epithelium to a thin simple epithelium.
Autoradiographic studies on the distribution of labeled maternal RNA in early mouse embryos
Authors: Bachvarova Rosemary , Moy Keiko
Published: June 2005

Maternal RNA of mouse eggs and embryos was labeled by exposure of growing ovarian oocytes to 3H‐uridine in vivo 8 to 16 days before ovulation and fertilization. Labeled embryos from the 1‐cell stage to the blastocyst stage were collected, fixed, and autoradiographs of plastic sections prepared. The observed grain density was similar in the pronuclei and in the cytoplasm of 1‐cell embryos. Knowing the volumes of nucleus and cytoplasm, it was determined that 3% of the maternal RNA was found in the pronuclei. It is suggested that some of this nuclear RNA may be stable small nuclear RNAs (e.g. U1 RNA) retained from the germinal vesicle stage through meiotic maturation. During the 2‐cell stage and beyond, maternal RNA is degraded and labeled precursor is reincorporated into nuclear RNA, making it difficult to accurately quantitate the amount of nuclear maternal RNA. It is known that about one third of the total maternal RNA is lost between the 8‐cell and blastocyst stages. It was found that cytoplasmic grain densities in inner and outer cells of the morula and blastocyst were not significantly different. Thus, the loss of maternal RNA does not proceed more rapidly in the differentiating trophoblast than in the inner cell mass.
Relative developmental success of interspecific Lepomis hybrids as an estimate of gene regulatory divergence between species
Authors: Parker Henry R. , Philipp David P. , Whitt Gregory S.
Published: June 2005

The developmental success of interspecific Lepomis hybrids is used as an index of gene regulatory divergence between the green sunfish, L. cyanellus, and each of three other parental species, longear sunfish, L. megalotis, warmouth, L. gulosus, and bluegill, L. macrochirus. This gene regulatory divergence is compared to the degree of structural gene divergence among these four species (genetic distance [Nei, '78], D, ranged from 0.206 to 0.586). The developmental success of the hybrid embryos at the level of morphogenesis was higher than expected from the genetic distance between the parental species. The rates of morphogenesis of the hybrid embryos were the same as that for the green sunfish embryos. The percentage of embryos that hatched was relatively high in all crosses. However, two of the hybrid crosses resulted in enhanced percentages of hatched embryos. Slight increases in the extent of morphological abnormalities were observed in hybrids from crosses between more distantly related parental species.

The schedules and levels of enzyme locus expression of the hybrids, assessed spectrophotometrically and electrophoretically for nine enzyme systems (encoded in a total of 14 loci), were different from each other and from those of the green sunfish embryos. Alterations in the time of first enzyme appearance and in the time of first increase in enzyme activity in the developing hybrid embryos were not correlated with genetic distance between parental species. However, the extents of alteration of enzyme activities over the entire period of hybrid embryogenesis were correlated with the genetic distance.

We attribute the morphological and molecular anomalies observed in the hybrids to gene regulatory incompatibilities between species. Although the exact number of mutational differences and their relative developmental impacts are not known, some inferences can be drawn about the degree of divergence in gene regulation between species. It appears that an uncoupling of the rates of structural and regulatory gene evolution can occur between species of some taxa, an observation that has implications for the roles of gene regulatory differences in organismic evolution.
On the diversity of sperm histones in the vertebrates: IV. Cytochemical and amino acid analysis in Anura
Authors: Kasinsky H. E. , Huang S. Y. , Mann M. , Roca J. , Subirana J. A.
Published: June 2005

The variability of sperm histones in frogs has been studied by cytochemical and amino acid analyses. Cytochemically, Rana sperm proteins fall into Bloch's ('69, '76) type 4 somatic‐like histone category, while Xenopus and Bufo have type 3 intermediate sperm histones. Extractability in 5% trichloroacetic acid (TCA) at different temperatures splits this type 3 category into two groups: type 3B intermediate sperm histones of Bufo are extractable at 85–90°C, while Xenopus intermediate type 3A sperm histones require temperatures of 95–100°C for extraction. Amino acid analysis confirms that Rana sperm histones are of the nucleosomal type, with a testis‐specific, very lysine‐rich H1 histone. The sperm protein in Bufo is richer in arginine than the proteins in Xenopus. Both of these genera contain lysine and histidine as well as arginine in their sperm proteins. These results confirm earlier electrophetic data (Kasinsky et al., '78) and indicate that sperm histones in the order Anura can vary markedly between different genera.