bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors influencing testosterone metabolism by anuran larvae
Authors: Hayes Tyrone B. , Licht Paul 
Published: June 2005

AbstractThe effects of experimental conditions—steroid concentration, temperature, treatment duration, tadpole density, and delivery mode—on testosterone (T) metabolic rates were examined in larval anurans. T uptake into tadpoles was measured by scintillation counting of [3H]T and metabolism of T was studied by thin layer chromatography in two anuran species, the African clawed frog (Xenopus laeuis) and the western toad (Bufo boreas). T was extensively metabolized by both species, but the effects of each experimental condition on T metabolism varied between species. In the study of delivery mode, tadpoles injected with T dissolved in saline metabolized T faster than animals in groups where the steroid was added directly to the water. Animals injected with T dissolved in oil metabolized T the slowest, but T was short‐lived in all cases. The current study demonstrates that concentration, temperature, treatment duration, tadpole density, and delivery mode may all affect steroid metabolic rates, but these effects vary between species in unpredictable ways. Since steroid metabolism may either activate or deactivate steroids, these factors are important in understanding the potency of steroids in tadpoles. A review of the literature dealing with steroid effects in anuran larvae illustrates these problems. © 1995 Wiley‐Liss, Inc.
Effects of unilateral cranial sympathectomy either alone or with sensory nerve sectioning on pedicle growth in red deer (Cervus elaphus)
Authors: Suttie James M. , Li Chunyi , Sheard Philip W. , Corson Ian D. , Waldrup Kenneth A. 
Published: June 2005

AbstractIn a previous study (Li et al., [1993], J. Exp. Zool., 267: 188–197) sensory nerve sectioning had no effect on the timing of pedicle growth. The aim of the present study was to determine whether sensory nerve sectioning in conjunction with sympathectomy would influence pedicle growth. Twelve intact male red deer claves were allocated to treatment before any pedicle growth as follows: 1) unilateral sensory nerve removal (USX, n = 5), 2) unilateral superior cervical ganglionectomy (SGX, n = 4), or 3) both USX and SGX (SG/USX, n = 3). The calves were observed weekly. In all cases the untreated side was the control. Pedicle initiation was measured with a pedicle detector and after initiation, growth was measured with a ruler. When the treated pedicles reached a length of 60 mm the calves were killed and tissues from the pedicle were examined immunohistochemically for nerves. No large bundles of nerves were observed in the treated pedicle although a few fine fibres were present. All calves grew pedicles. There were no significant differences in the timing of pedicle initiation either within treatment or between treatments. All denervated pedicles grew faster than controls and were consequently higher at examination. The fact that pedicle growth took place despite reduced innervation indicates that a continuous neural connection is not a pre‐requisite for normal pedicle growth. © 1995 Wiley‐Liss, Inc.
Sex reversal by testosterone and not by estradiol or temperature in Calotes versicolor, the lizard lacking sex chromosomes
Authors: Ganesh Subramaniam , Raman Rajiva 
Published: June 2005

AbstractThe garden lizard Calotes versicolor lacks identifiable sex chromosomes. The present study demonstrates that temperature has no apparent effect on the determination of sex. In embryos reared at higher temperature (32°, 34°, 35°C), the gonads differentiate earlier than in controls and the overall duration of embryonic incubation is dramatically reduced. Exogenous administration of testosterone (100 μg/egg) to embryos of stages 28, 30, and 33 results in the majority of them developing into males; no female is encountered. Testosterone also accelerates the differentiation of testes. Estradiol (5, 10, μg/egg), administered at the same stages as testosterone, does not show any effects on gonadal differentiation. These results indicate that in C. versicolor, female is the default sex and the male is heterogametic. Apparently, this is the first report in a reptile in which testosterone has been shown to cause reversal into male sex. © 1995 Wiley‐Liss, Inc.
Oocyte and zygote zona pellucida permeability to macromolecules
Authors: Legge Michael 
Published: June 2005

AbstractZona pellucida intact mouse pre‐and post‐ovulatory oocytes and zygotes were investigated for permeability to macromolecules using graded neutral fluorescein isothiocyanate (FITC) dextrans (molecular weight range 3.84–170 kDa) and a range of galactose‐binding lectins (molecular weight range 40–247 kDa). The use of both FITC neutral dextrans and FITC galactose‐binding lectins gave good agreement in the zona pellucida permeability studies. Zona pellucida intact pre‐and post‐ovulatory oocytes were permeable to both markers up to a molecular weight range of 170 kDa although movement across the zona pellucida was diminished between 100 to 150 kDa with no detectable permeability at molecular weight range of 170 kDa. Zygotes demonstrated a decreased zona pellucida permeability at around 110 kDa. Two galactose‐containing oligosaccharide‐rich zones in the zona pellucida were identified, and changes in zygote vitelline membrane galactose‐binding lectin affinity were detected. © 1995 Wiley‐Liss, Inc.
Bone regrowth in young mice stimulated by nail organ
Authors: Zhao Weiguang , Neufeld Daniel A. 
Published: June 2005

AbstractRecent studies of postamputational repair following digit‐tip amputation revealed am unexpected correlation between nail regrowth and bone regrowth in mice. To examine putative effects of nail on bone regrowth, phalangeal tips were amputated such that nail was artificially removed from distal levels or retained following proximal level amputations. In the absence of nail, bone did not regrow at distal levels. Conversely, when nail was surgically retained bone regrew form proximal levels. The nail organ profoundly influences bone regrowth. © 1995 Wiley‐Liss, Inc.
Androstenedione metabolism in the indifferent stage of bovine gonad development
Authors: Juárez‐Oropeza M. A. , López V. , Álvarez‐Fernández G. , Gómez Y. , Pedernera E. 
Published: June 2005

AbstractSuspensions of cells obtained from genital ridges and gonads of bovine embryos of 1.0‐3.4 cm in crown‐rump (C‐R) length were used for studies of the metabolism of radiolabeled exogenous steroid precursor. Tritiated androstenedione was employed as precursor and the final products of their metabolism were evaluated after separation by thin‐layer chromatography. Genetic sex was determined by the karyotype of hepatocytes from the same embryos. The extent of conversion of tritiated androstenedione was higher in cells from male embryos than cells from female embryos. Furthermore, androstenedione was metabolized mainly to testosterone in male embryos. By contrast, cells obtained from female embryos transformed androstenedione to estrone and 17β‐estradiol. The onset of this activity was observed at 1.8 cm in C‐R length in males and at 2. 2 cm in C‐R length in females. In all cases, after the onset, the metabolic activity increased in relation to the age of the embryos. These data show that in the bovine embryo gonad, the activity of aromatase and 17β‐hydroxysteroid dehydrogenase are present when the morphological differentiation of the gonadal sex has not yet been established. © 1995 Wiley‐Liss, Inc.
Mode of action of the neurotransmitter 5‐hydroxytryptamine in stimulating ovarian maturation in the red swamp crayfish, Procambarus clarkii: An in vivo and in vitro study
Authors: Sarojini Rachakonda , Nagabhushanam Rachakonda , Fingerman Milton 
Published: June 2005

AbstractOvarian explants from the red swamp crayfish, Procambarus clarkii, were incubated with 5‐hydroxytryptamine (5‐HT) and muscle, and with 5‐HT in combination with eyestalk tissue, brains, or thoracic ganglia. In vitro, 5‐HT without brain or thoracic ganglia in the incubation medium had no significant effect on the ovarian explants. In contrast, in vitro brains and thoracic ganglia induced ovarian maturation, indicating the presence of a gonad‐stimulating hormone (GSH) in these tissues. However, this in vitro stimulatory effect was significantly greater when 5‐HT was present in the incubation medium with the brains and thoracic ganglia. These results provide in vitro evidence in support of the hypothesis that the previously observed in vivo stimulatory action of 5‐HT on the ovaries is an indirect one, 5‐HT acting to stimulate release of a GSH. © 1995 Wiley‐Liss, Inc.
Modulation of avian responsiveness to chemical irritants: Effects of prostaglandin E1 and analgesics
Authors: Clark Larry 
Published: June 2005

AbstractChemical irritation appears to be modulated by similar mechanisms in birds and mammals, despite an apparent difference between the two taxa for what constitutes a chemical irritant. Prostaglandin E1, a well‐described mammalian pain modulating substance, was not itself aversive to starlings, although it did sensitize birds to the effects of the avian irritant oaminoacetophenone. Aspirin and aspirin‐like drugs tended to desensitize starlings to the aversive effects of acetophenone bird repellents. Because the modulation mechanisms for the perception of pain appear to be similar in birds and mammals, the taxonomic differences in the perception of stimuli as irritating is inferred to be due to differences in receptor mechanism. The differences in sensory perception of chemical irritants has important implications for vertebrate foraging ecology and the evolution of plant‐animal interactions. © 1995 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America
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Purification of a 240 kDa protein from serum and follicular fluid of water buffalo and its identification as haptoglobin
Authors: Bergamo P. , Balestrieri M. , Carratore V. , Abrescia P. 
Published: June 2005

AbstractThe fluids from healthy growing follicles of water buffalo were previously found free of the polypeptides H (Mr 36,000) and L (Mr 21,000) which were instead detected in fluids from atretic follicles and blood. Here we report evidence that these two polypeptides, as selected from serum by specific anti‐L antibodies, are the subunits of an oligomeric protein. The protein was purified from serum or follicular fluid, and its molecular weight (240 kDa), isoelectric point (6. 5), and amino acid composition were determined. The NH2‐terminal sequences of the subunits L and H were analyzed: 100% and 90% homology with α and β chains of bovine haptoglobin, respectively, was found. Thus, haptoglobin can be used as a novel molecular marker to assess the physiological state of the blood‐follicle barrier or discriminate between atretic and healthy follicles. © 1995 Wiley‐Liss, Inc.
Maternal transfer of estradiol to egg yolks alters sexual differentiation of avian offspring
Authors: Adkins‐Regan Elizabeth , Ottinger Mary Ann , Park Jeanne 
Published: June 2005

AbstractThree experiments were conducted to determine whether avian egg yolks contain the sex steroid 17β‐estradiol and whether experimentally produced elevations in maternal estradiol alter yolk estradiol and influence sexual differentiation of the offspring. The yolks of eggs laid by Japanese quail (Coturnix japonica) were found to contain significant amounts of estradiol comparable to those in the maternal circulation. Treatment of laying females with estradiol benzoate (EB) resulted in elevated yolk estradiol and a permanent morphological alteration of female off‐spring in the form of an increased incidence of right oviducts in adulthood. Such maternal transfer of a sex steroid to the egg yolk constitute a potentially significant source of maternal influence over embryonic development and adult phenotype in oviparous species. © 1995 Wiley‐Liss, Inc.
Neuronal localization and evoked release of norepinephrine in the cnidarian Renilla koellikeri
Authors: Pani Amar K. , Anctil Michel , Umbriaco Denis 
Published: June 2005

AbstractNeuronal release of norepinephrine (NE) in the sea pansy Renilla koellikeri was investigated by searching for evidence 1) of neuronal localization of endogenous NE and 2) of synaptic‐like release of exogenously supplied NE in sea pansy tissues. Measurements of endogenous NE by high‐performance liquid chromatography with electrochemical detection corresponded with the visualization of specific NE immunoreactivity in six individual colonies thus sampled. Peroxidase‐antiperoxidase immunohistochemistry with antisera against NE‐aldehyde‐protein conjugates revealed that cellular NE immunostaining was predominantly associated with neurons and amoebocytes constituting the mesogleal nerve net. Transient increases of tritium outflow above background levels were evoked by field electrical stimulation of colonial (rachis) tissues pre‐loaded with 1 μM [3H]NE, under conditions that elicited nerve net‐mediated bioluminescence. This evoked release was largely reduced or abolished in a reversible manner by substituting high‐magnesium or calcium‐free seawater to normal seawater perfusate. Evoked release was significantly enhanced by exogenous norepinephrine (50 μM) and reduced in half or less by the α‐adrenergic blockers phentolamine and yohimbine (10 μM), thus providing support for the existence of an autoregulatory mechanism associated with release. These results suggest that neuronal, synaptic‐like release of NE occurs in the nerve‐net of the sea pansy, a representative of the phylum (Cnidaria) in which the first nervous systems of multicellular organisms are believed to have originated. © 1995 Wiley‐Liss, Inc.
Isolation and characterization of the cDNA encoding the spiny dogfish shark (Squalus acanthias) form of cytochrome P450c17
Authors: Trant John M. 
Published: June 2005

AbstractCytochrome P450c17 is a key steroidogenic enzyme for the production of sex steroids in gonadal tissue and for cortisol production in adrenal tissue. This protein possesses two enzymatic activities. The 17α‐hydroxylase activity results in the introduction of a hydroxyl group at the 17α‐position. The resultant 17α‐hydroxylated, C21 pregnene is converted to a C19 andro‐gen by the C17,20‐lyase activity. A cDNA library was constructed from poly(A)‐enriched mRNA isolated from spiny dogfish shark (Squalus acanthias) testis and ligated into EcoRI‐cut lambda arms. The amplified library was screened using a bovine P450c17 cDNA probe and five positive clones were isolated. The described cDNA encompasses 23 bp of the 5′‐untranslated region, a 1,527 bp open reading frame, and 414 bp of the 3′‐untranslated region. A putative polyadenylation signal (AATAAA) is 18 bp from the poly(A) tail. Northern blot analysis showed a single transcript of 1.9 kb, thus indicating the isolated clone is a full‐length cDNA. The deduced amino acid sequence of the shark form of P450c17 is 59% and 57% identical to the rainbow trout and chicken forms, respectively. The shark form is 43% to 46% identical to mammalian forms (rat, human, mouse, bovine, and porcine). There are large regions of extremely high identity shared among all the forms. The deduced shark 17α‐hydroxylase protein is 509 residues in length with a predicted weight of 57.2 kDa. Non‐steroidogenic COS cells, transfected with the shark P450c17 cDNA, was capable of 17α‐hydroxylase and C17,20‐lyase activities using both pregnenolone and progesterone as initial substrates. © 1995 Wiley‐Liss, Inc.
In situ detection of gonadotropin‐releasing hormone (GnRH) receptor mRNA expression in the rat ovarian follicles
Authors: Kogo Hiroshi , Kudo Akihiko , Park Min Kyun , Mori Takao , Kawashima Seiichiro 
Published: June 2005

AbstractTo clarify the target cells of GnRH in the ovary, in vivo expression of ovarian GnRH receptor mRNA was examined histologically by in situ hybridization in immature rats treated with PMSG only or in combination with hCG. Strong hybridization signals were observed in the granulosa cells of atretic follicles. However, no significant signals were found in the granulosa cells of healthy small, preantral, or early antral follicles. Healthy Graafian and preovulatory follicles also showed intense signals in their mural granulosa cells, but no signals were detected in the cumulus oophorus cells. Corpora lutea showed only weak signals, but luteinizing follicles probably after atresia exhibited signals of moderate intensity in their luteinized and remaining granulosa cells. No signals were detected in the theca cells and oocytes in all the follicles. Interstitial cells sometimes exhibited hybridization signals of moderate intensity, when the cells were eosinophilic. Pretreatment with different combinations of gonadotropins yielded different ovarian histology, but this had no influence on the localization of hybridization signals. These results, showing that the authentic GnRH receptor mRNA was expressed in a certain cell population in the rat ovary, suggest that the receptor is involved in the control of various ovarian functions including follicular development, atresia, ovulation, and luteinization after ovulation and follicular atresia. © 1995 Wiley‐Liss, Inc.
Analysis of ciliary beat frequencies in hamster oviducal explants
Authors: Di Carlantonio G. , Shaoulian R. , Knoll M. , Magers T. , Talbot P. 
Published: June 2005

AbstractWe have developed a simple direct method, requiring minimal manipulation, to measure beat frequencies of the cilia on the external surface of hamster oviducal infundibula in vitro. Two perfusion chambers (closed and open) were used; both can be hand‐made in a few minutes and discarded after use. Ciliary beat frequencies were determined by measuring variations in light intensity with time in a single pixel positioned over a video image of the beating cilia. Data files were collected using Image 1 software and later transferred to PSI Plot or Lotus 123 spreadsheets for analysis by counting the number of brightness peaks recorded per second or by subjecting the data to Fourier transformation with or without smoothing. These methods of analysis gave similar results. To verify that Image 1 data files contain accurate representations of CBF, videotapes of beating cilia were made and subjected to frame‐by‐frame analysis. Image 1 interfaced with a standard video camera was found to collect reliable data over a beat frequency range of 0‐‐15 cycles/sec. In some Fourier transforms, secondary peaks were observed and were shown to represent cilia beating at more than one frequency in a sampled region. Coefficients of variation for repeated measurements taken on the same region varied from 4.1% to 9.0%. Small but significant differences were found between beat frequencies at different regions of the same oviduct. When chambers were perfused discontinuously and measurements of beat frequency were made at least 5 min after each perfusion, no effect of perfusion on frequencies was observed. However, during continual perfusion of the open chamber, a slight but significant increase in beat frequency was observed after perfusion was initiated. Muscle contraction, which sometimes occurs in the open chamber, did not affect beat frequency measurements. Infundibula could be stored at 4°C overnight without any negative effect on beat frequencies. Cold storage also reduced muscle contraction. Placement of a small coverslip on infundibula in the open chambers was also found to reduce muscle contraction and facilitate beat frequency measurements. Coverslipping did not affect beat frequencies. This method of beat frequency analysis will be valuable for analyzing factors that regulate or influence cilia in mammalian oviducts. © 1995 Wiley‐Liss, Inc.
On the c‐mos proto‐oncogene product during meiotic maturation in bovine oocytes cultured in vitro
Authors: Tatemoto Hideki , Terada Takato 
Published: June 2005

AbstractThe present study was carried out using dot‐blot Western analysis with pp39mos‐specific polyclonal antibodies to examine the quantitative and qualitative changes of c‐mos proto‐oncogene product, Mos, during bovine oocyte maturation in vitro. Mos is present throughout meiotic maturation, is produced from around the onset of meiotic resumption, and is phosphorylated on germinal vesicle breakdown. These results indicate for the first time that the synthesis and phosphorylation of Mos during maturation culture play a key role in the accomplishment of meiosis in bovine oocytes. © 1995 Wiley‐Liss, Inc.
Laterality of aggressive responses in Anolis
Authors: Deckel A. Wallace 
Published: June 2005

AbstractThis experiment examined whether or not aggression in the lizard Anolis (suborder Lacertilia, family Iguanidae) is lateralized. Five pair of adult Anolis were subjected to several 20 min behavioral trials, during which one animal was placed in the cage of the other. Behaviors were captured on video and coded according to eye preference, motor activity, posture, and color. Analysis of the data found that the most aggressive behaviors, including biting, threatened biting, and aggressive movements, were done under the guidance of the left eye. Both left and right eyes were used with equal frequency during non‐aggressive movements. Most of these aggressive episodes were done while the animals were “lightly” colored. Because of an almost complete crossing‐over of the optic tract in Anolis, along with the absence of a corpus callosum, it is likely that most, if not all, of the information in the left eye was processed by the right hemisphere. These results suggest that the lizard Anolis, like humans, rats, and chicks, may mediate aggressive responses predominantly through right‐hemispheric brain mechanisms. © 1995 Wiley‐Liss, Inc.
Purification and properties of two malic enzyme activities in liver mitochondria of Squalus acanthias (spiny dogfish)
Authors: Zhou Xiaoqin , Korte Joseph J. , Anderson Paul M. 
Published: June 2005

AbstractTwo malic enzymes are present in liver mitochondria from Squalus acanthias (spiny dogfish), an NAD(P)‐dependent and an NADP‐dependent malic enzyme. The NAD(P)‐dependent enzyme was partially purified and found to have kinetic properties similar to other malic enzymes; the molecular weight is ≈ 130,000. The maximal rate with NADP is 40% of the maximal rate with NAD. The NADP‐dependent malic enzyme was purified to homogeneity and also has properties similar to other malic enzymes, including a subunit molecular weight of ≈ 61,000 and a native molecular weight of ≈ 250,000; however, the rate as a function of malate concentration is described by a sigmoid curve. Both enzymes require either Mn2+ or Mg2+ for activity, are activated by fumarate or succinate, and are inhibited by ATP. Both enzymes are inhibited by low concentrations of oxalacetate; the Ki for competitive inhibition of the NAD(P)‐dependent malic enzyme by oxalacetate is 4 μM. The Km for Mn2+ is considerably lower than the Km for Mg2+ for both enzymes; the maximal rate with Mg2+ is about the same as with Mn2+ for the NADP‐dependent enzyme, but only 20% of that with Mn2+ for the NAD(P)‐dependent enzyme. The possible role of these enzymes in contributing to citrate synthesis by isolated spiny dogfish liver mitochondria is discussed. NAD‐ or NADP‐dependent malic enzyme activity could not be detected in the cytosol. © 1995 Wiley‐Liss, Inc.
Freezing of zona‐free mouse embryos: Characteristics of the plasma membrane and subsequent development of the embryos
Authors: Martí M. , Nogués C. , Egozcue J. , Ponsà M. 
Published: June 2005

AbstractFrozen‐thawed mouse embryos with (+ZP) and without (−ZP) zona pellucida have been studied at the Scanning Electron Microscope (SEM) to determine how the process affects the plasma membrane and the subsequent embryo development. The main difference observed in −ZP embryos immediately after thawing is the abnormal morphology and distribution of microvilli. This could explain the spontaneous separation of blastomeres in ‐ZP embryos, and the decrease in their survival rate. If thawed −ZP embryos are allowed to recover in culture, their plasma membrane characteristics and survival rate are identical to those of control embryos. © 1995 Wiley‐Liss, Inc.