bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular homology of coexpressed eye‐ and liver‐specific lactate dehydrogenase isozymes from the basketmouth cichlid assessed by oxamate‐Sepharose and blue dextran‐Sepharose affinity chromatography
Authors: Leibel Wayne S. , Peairs Kimberly S.
Published: June 2005

Recently, several teleost fishes (Perciformes, Cichlidae) have been found that coexpress both a cathodal, liver‐specific and an anodal, eye‐specific lactate dehydrogenase (LDH), and evidence supporting the hypothesis that these are the products of two distinct genes has been presented (Holt and Leibel, '87). In this study, the molecular homology of these two isozymes from the basketmouth cichlid, Acaronia nassa, relative to each other and to eye‐specific and liver‐specific isozymes from a variety of other fishes is assessed by oxamate‐Sepharose and blue dextran‐Sepharose affinity chromatography. Whereas the eye‐specific isozyme from the basketmouth cichlid and all other LDHs from a variety of vertebrates bound tightly to the oxamate column in the presence of the cofactor NADH, the liver‐specific isozyme from basketmouth, and the testes‐specific LDH‐X from rat failed to bind. Similarly, the liver‐specific isozyme from basketmouth failed to bind to the blue dextran column, whereas the liver‐specific C4 from goldfish (Cypriniformes) bound and eluted with NADH; the eye‐specific C4 from three cichlids, including the basketmouth, and rat testis‐specific LDH‐X bound and eluted with NAD+. These results suggest that the eye‐ and liver‐specific LDH isozymes from the basketmouth cichlid are not encoded by the same locus and that this liver‐specific isozyme is very different from analogous isozymes that occur in various Cypriniform and Gadiform fishes.
Phosphofructokinase in the mantle of the sea mussel Mytilus galloprovincialis Lmk.
Authors: Villamarin J. A. , Rodriguez‐Torres A. M. , Ibarguren I. , Ramos‐Martinez J. I.
Published: June 2005

Phosphofructokinase (PFK) from the mantle of Mytilus galloprovincialis Lmk. was purified 302‐fold with a yield of 27%. The enzyme proved to be a 340,000‐dalton oligomer comprising four identical 85,000‐dalton subunits.

Like other phosphofructokinases, the enzyme behaved cooperatively with fructose 6‐phosphate and was inhibited by high concentrations of ATP.

The fall in pH value produces a decrease of enzyme affinity for Fru 6‐P and for the activator AMP, together with a greater inhibition by ATP.

AMP, cyclic AMP, and fructose 2,6‐bisphosphate increased the affinity of mussel mantle PFK for Fru 6‐P and decreased the inhibition by ATP, while ammonium ions activated the enzyme increasing only the Vmax. Phosphoenolpyruvate acted as an inhibitor, decreasing the affinity of the enzyme for Fru 6‐P.
Avian vasculogenesis and the distribution of collagens I, IV, laminin, and fibronectin in the heart primordia
Authors: Drake Christopher J. , Davis Lynn A. , Walters Luanne , Little Charles D.
Published: June 2005

The heart‐forming regions of the early embryo are composed of splanchnic mesoderm, endoderm, and the associated ECM. The ECM of the heart‐forming regions in stage 7–9 chicken embryos was examined using immunofluorescence. Affinity purified antibodies to chicken collagens type I and IV, chicken fibronectin, and mouse laminin were used as probes. We report that (1) the basement membrane of the endoderm contains immunoreactive laminin and collagen IV; (2) the nascent basement membrane of the heart splanchnic mesoderm contains immunoreactive laminin, but not type IV collagen, and (3) the prominent ECM between the splanchnic mesoderm and the endoderm (the primitive‐heart ECM) contains collagen IV, collagen I, fibronectin, but not laminin. In addition, we describe microscopic observations on the spatial relationship of cardiogenic cells to the primitive‐heart ECM and the endodermal basement membrane.
Seasonality in plasma thyroxine binding in turtles
Authors: Licht Paul , Denver Robert J. , Pavgi Sushama , Herrera Brenda
Published: June 2005

The relation between seasonal changes in plasma thyroxine (T4) and T4 binding activity was studied in three species of turtle previously shown to differ in the nature of their binding proteins; additional direct measurements of a high affinity T4 binding protein (TBP) were made in one species using RIA. In the painted turtle, Chrysemys picta (Family Emydidae), a species with large seasonal changes in plasma T4, the binding protein measured by activity and RIA showed significant seasonality. Binding activity correlated with direct estimates of TBP by RIA. TBP was minimal upon emergence from hibernation and maximal in late summer (July–August), about a month after the peak in plasma T4. In contrast, two other nonemydid species, the green turtle (Chelonia mydas) and Mexican tortoise (Gopherus flavomarginatus) showed relatively low plasma T4 and binding activity with no significant seasonality in either. Electrophoretic studies (PAGE) confirmed that T4 binding in C. picta is almost wholly associated with a high affinity, low capacity TBP; whereas, it is confined to high capacity sites (probably albumin) in the other species. The transport of T4 is clearly handled differently in these three turtles. In the green turtle and tortoise, one would expect relatively constant free T4 (fT4) throughout the year. Marked seasonal fluctuations (an order of magnitude) in the ratios of TBP to total T4 in C. picta due to the temporal lag between the two may cause profound changes in fT4 with peaks in late spring.
Defensive function of trichocysts in Paramecium
Authors: Harumoto Terue , Miyake Akio
Published: June 2005

A putative defensive function of trichocysts in Paramecium has been tested experimentally. Cells of trichocyst‐non‐discharge (tnd) mutant, artificially induced trichocyst‐deficient cells, and intact wild‐type cells were compared as prey for a carnivorous ciliate, Dileptus margaritifer. Cells of tnd mutants were eaten 9–45 times faster than wild‐type cells by the predator in P. caudatum and P. tetraurelia. Encounters between paramecia and dilepti occurred in nearly the same frequency in mutant and wild‐type cells. Paramecia with reduced numbers of trichocysts were obtained in P. caudatum, P. jenningsi, and P. tetraurelia by treating wild‐type cells with lysozyme, an inducer of trichocyst discharge. These cells were eaten faster than intact cells by the predator and the rate of predation was inversely correlated with the remained capacity of trichocyst discharge. It was concluded that the discharge of trichocysts defends these species of Paramecium against D. margaritifer. Therefore, the results of this work strongly support the hypothesis that trichocysts in Paramecium function as defensive organelles against predators. The results also support the hypothesis that the offense‐defense interaction between Dileptus and Pramecium is mediated by their extrusomes (toxicysts and trichocysts) and suggest that extrusomes in ciliates function as organelles for interspecific cell‐cell interaction.
Sexing of rat embryos with antisera specific for male rats
Authors: Utsumi Kyozo , Satoh Eisuke , Iritani Akira
Published: June 2005

Male‐specific antigenicity (H‐Y antigen) of rat embryos has been examined, and the feasibility of sexing rat embryos by use of H‐Y antibodies has been studied. Rat H‐Y antisera were produced by immunization of female Wistar rats with a homogenate of testes from male Wistar neonates. Male specificity of the antiserum (H‐Y antibody) was determined by retention of cytoxicity to male epidermal cells after absorption with female cells. After cultivation of rat embryos for 5 to 6 hr in the presence of antibody, half of the embryos were arrested at the morula stage. However, these embryos developed into blastocysts after removal of the antiserum, and then they grew into male young in recipient foster mothers. Eighty percent of the embryos that developed to blastocysts in the presence of the antiserum grew into female young.
Progression of Oocyte Maturation From Metaphase I to Metaphase II is disturbed by previous immunological interference with cumulus cell function
Authors: Tesarik Jan , Lefèvre Brigitte , Testart Jacques
Published: June 2005

The effects of an antibody preparation reacting with preovulatory mouse cumuli oophori (anticumulus Ig) on oocyte maturation in vivo and in vitro were studied. Continuous presence of anticumulus Ig in culture medium did not impair oocyte maturation in vitro. Similarly, no effect on oocyte maturation in vivo was observed when anticumulus Ig was given to females superovulated with pregnant mare serum gonadotopin (PMSG) and human chorionic gonadotropin (hCG) at the time of hCG treatment. However, when administered earlier, anticumulus Ig brought about serious disturbances of oocyte meiotic competence, since only immature oocytes were ovulated after anticumulus Ig injection at the time of PMSG treatment and as much as 70% of the ovulated oocytes were immature when the antibody was applied 24 hr later. Previous absorption of anticumulus Ig with isolated cumulus cells removed the inhibitory effect of this preparation on oocyte meiotic competence to the same extent as absorption with whole cumuli oophori, despite the persistence of a strong reactivity of the cumulus cell‐absorbed antibody preparations with the cumulus intercellular matrix. The ability of oocytes obtained from antibody‐injected animals to mature in vitro was also considerably impaired when the injection was made at the time of PMSG treatment. In all cases the maturation defect concerned the progression of meiosis from metaphase I to metaphase II, while the ability of oocytes to undergo germinal vesicle breakdown (GVBD) was unchanged. It is concluded that (1) the competence of oocytes to progress from metaphase I to metaphase II of meiosis can be subject to an isolated alteration without any disturbance of GVBD, (2) the cumulus cells sustain the development of the oocyte competence to effect the metaphase I–metaphase II transition, and (3) this activity of cumulus cells is limited in time and coincides with the PMSG action in the standard superovulation regimen.
Oocyte recovery and maturation in the American black bear (Ursus americanus): A model for endangered ursids
Authors: Johnston L. A. , Donoghue A. M. , Igo W. , Simmons L. G. , Wildt D. E. , Rieffenberger J.
Published: June 2005

A study was conducted to determine if meiotic maturation could be induced in ovarian oocytes of the American black bear (Ursus americanus), a model for gamete “rescue” techniques for endangered ursids. Ovaries obtained from 48 black bears yielded 2,403 oocytes (51.1 ± 4.9/female), of which 777 (32.3%) were morphologically classified as excellent quality. More total oocytes were recovered from donors that were anestrous compared to luteal/pregnant (P < 0.05) at the time of ovarian excision. Delaying the recovery of oocytes from antral follicles within excised ovaries from 12–24 hr to 25–36 hr had no effect (P > 0.05) on the overall number of high quality oocytes recovered or subsequent maturational ability. The highest incidence of metaphase II was reached between 48 and 60 hr of in vitro incubation. Donor status (anestrous vs. luteal/pregnant) had no influence on the oocyte maturation rate by 24 or 48 hr, but by 60 hr, more (P < 0.05) oocytes recovered from anestrous females (43.9%) had achieved metaphase II compared to luteal/pregnant counterparts (23.1%). In preliminary trials involving endangered ursids, 54 ovarian oocytes were recovered from three aged sun bears (Helarctos malayanus), of which 72.2% were excellent quality and 15.4% matured in vitro to metaphase II. Similarly, 119 antral oocytes were recovered from two aged sloth bears (Melursus ursinus), of which 41.2% were excellent and 17.5% matured in vitro. These results demonstrate that: (1) ursid oocytes undergo nuclear maturation in vitro; (2) reproductive status of the donor influences the total number and maturational ability of recovered oocytes; and (3) preliminary observations suggest the American black bear to be a useful model for developing oocyte rescue techniques for related but endangered species. © Wiley‐Liss, Inc.
Small cardioactive peptide B increases the responsiveness of the neural system underlying prey capture reactions in the pteropod mollusc, Clione limacina
Authors: Norekian Tigran P. , Satterlie Richard A.
Published: June 2005

Effects of small cardioactive peptide B (SCPB) on cerebral neurons which underlie prey capture in the carnivorous pteropod mollusc, Clione limacina, were investigated. SCPB in concentrations of 10 μM and higher produced direct activation of cerebral ganglion neurons underlying extrusion of buccal cones used in prey capture. SCPB in lower concentrations, between 1 and 5 μM, did not have a noticeable effect on the membrane potentials of these neurons; however, it significantly increased their responsiveness to sensory inputs from the tactile stimulation of the head, and their ability to generate afterdischarge activity.

SCPB immunoreactivity was observed in cell bodies in buccal, cerebral, pedal, and intestinal ganglia, as well as in the anterior esophagus and in buccal cones where fibers stained intensely. These electrophysiological and immunohistochemical data suggest that SCPB may have a physiological role in feeding arousal in Clione. © 1994 Wiley‐Liss, Inc.
TGFβ1 regulation of collagen metabolism by embryonic palate mesenchymal cells
Authors: D'Angelo Marina , Chen Jing‐May , Ugen Kenneth , Greene Robert M.
Published: June 2005

Proper metabolism of the extracellular matrix (ECM) in mammalian embryonic palatal tissue is required for normal development of the palate. In particular, perturbation of collagen metabolism in the embryonic orofacial region results in the production of cleft palate. Although several types of collagen have been localized in the embryonic palate, factors responsible for regulating their synthesis have not been identified. Transforming growth factor β (TGFβ), shown to be capable of modulating ECM metabolism in other tissues, has been localized in the developing palate. Thus, we examined the ability of TGFβ1 to modulate collagen synthesis and degradation in murine embryonic palate mesenchymal (MEPM) cells in vitro.

Immunohistochemical analysis confirmed that type III collagen was predominant in the mesenchyme of the embryonic palate, whereas type I collagen was ubiquitous throughout palatal epithelium and mesenchyme. Total collagen production by TGFβ‐treated confluent MEPM cells in serum‐free conditioned medium was determined by measuring incorporation of L‐[2‐3‐4‐5‐3H]‐proline into hydroxyproline. Treatment for 24 hr with TGFβ1 stimulated incorporation into both cell layer and medium fractions. Quantification of collagen types by ELISA indicated that TGFβ1 stimulated the accumulation of type III collagen as early as 3 hr after treatment. Northern blot analysis of MEPM cells treated with TGFβ1 revealed that steady‐state levels of mRNA encoding for procollagen α1(I) and α1(III) were increased and that these effects were ablated by cycloheximide but not actinomycin. The effects of TGFβ treatment on MEPM cell collagen levels also reflected alterations in collagen degradation. TGFβ‐treated MEPM cells exhibited a significant diminution of total protease activity. Moreover, analysis by substrate gel electrophoresis indicated specific decreases in vertebrate collagenase and stromelysin. These data represent the first report of changing proteolytic profiles during palatogenesis. Thus, TGFβ regulates the amount of collagen present in embryonic palatal tissue at the level of synthesis and degradation. © 1994 Wiley‐Liss, Inc.
Brief treatment with an aromatase inhibitor during sex differentiation causes chromosomally female salmon to develop as normal, functional males
Authors: Piferrer Francesc , Zanuy Silvia , Carrillo Manuel , Solar Igor I. , Devlin Robert H. , Donaldson Edward M.
Published: June 2005

Although many studies implicate sex steroids in the process of sexual differentiation, the exact role played by these substances in lower vertebrates, especially teleost fish, is not clear, since it is not conclusively known whether sex steroids are the cause or an early consequence of sex differentiation. By hormonal manipulation and specific crossings, it is possible to produce all‐female stocks of the otherwise gonochoristic chinook salmon (Oncorhynchus tshawytscha). These all‐female stocks are an excellent model to study the effects of steroids on sexual differentiation since the genetic sex is known before the actual differentiation of the embryonic gonads takes place. In the present study, we show that treatment with a nonsteroidal inhibitor of aromatase, the enzyme that catalyzes the conversion from androgens to estrogens, for only 2 hours when the gonads were bipotent, caused genetic females to develop into normal males. Furthermore, these males had testes which were indistinguishable both in size and in structure from those of genetic males, and completed all the stages of spermatogenesis. At 2 years of age, these males produced viable sperm capable of inducing normal embryonic development when used to fertilize eggs, with a resulting all‐female progeny. These results provide strong support for Yamamoto's theory (Yamamoto, '69) that androgens and estrogens are natural sex inducers in gonochoristic fish, and suggest that aromatase plays a pivotal role in the sex differentiation of salmon. Thus, by brief treatment with an aromatase inhibitor at a specific time in development, an organism was induced to develop a funtional, phenotypic sex different from its genetic sex. © 1994 Wiley‐Liss, Inc.
Evidence for a developmental and evolutionary link between placodal ectoderm and neural crest
Authors: Smith Steven C. , Graveson Ann C. , Hall Brian K.
Published: June 2005

The premature death (p) mutation in the Mexican axolotl (Ambystoma mexicanum) affects the ability of ectoderm to produce normal neural crest cells. We have examined the effect of this mutation on the development of a derivative of placodal ectoderm—the lateral‐line system—and found that both migration of lateral‐line primordia and differentiation of mechanoreceptive neuromast organs are disrupted in p/p embryos. These effects cannot be explained by the presence of other mutant tissues, since development is also abnormal when lateral‐line placodes from mutant embryos are transplanted into wild‐type hosts. Furthermore, wild‐type placodes develop normally in mutant embryos. Thus, the p gene affects both placodal and neural crest cell development. These results strongly suggest that neural crest cells and placodal ectoderm arise in response to common developmental interactions, which could indicate that they were derived from an ancestral precursor tissue. © 1994 Wiley‐Liss, Inc.
Long‐lasting, sex‐specific inhibition of serotonin‐induced spawning by methiothepin in the zebra mussel, Dreissena polymorpha (Pallas)
Authors: Fong Peter P. , Hardege Jorg D. , Ram Jeffrey L.
Published: June 2005

Zebra mussels (Dreissena polymorpha) can be stimulated to spawn with external application of serotonin. Inhibition of serotonin‐elicited spawning by methiothepin, a serotonin receptor ligand, was investigated. Methiothepin, which inhibits both male and female spawning when present concomitantly with serotonin (Fong et al. [1994a]) was demonstrated to cause long‐lasting inhibition of spawning in females for up to 12 days after its application. Mussels were exposed to various concentrations of methiothepin for 5 hours, rinsed with fresh water, and then tested with 10−3 M serotonin on the next day. Spawning in females that had been exposed to 10−5 M methiothepin was completely blocked, with little effect on male spawning. At methiothepin concentrations as low as 10−8 M, spawning latency in response to serotonin was significantly increased in females; higher concentrations also increased spawning latency in males. Exposure to 10−5 M methiothepin for as little as 30 minutes was sufficient to completely inhibit spawning in females, but not in males. A 21‐hour exposure to either 10−6 or 10−5 M methiothepin also significantly inhibited female spawning, with much smaller effects on males. Percent spawning in different groups of animals tested 1,2,4,8, and 12 days after a 5‐hour exposure to 10−5 M methiothepin was significantly reduced for females on all test days, but not for males. The mechanisms of this sex‐specific and long‐lasting inhibition of serotonin‐induced spawning are discussed with reference to receptor binding, retention, toxicity, and partial agonist properties of methiothepin. © 1994 Wiley‐Liss, Inc.
Cell cycle remodeling requires cell–cell interactions in developing Xenopus embryos
Authors: Frederick Debra L. , Andrews Matthew T.
Published: June 2005

Flow cytometric analysis has revealed a general remodeling of the cell cycle in developing Xenopus embryos. During early gastrulation the cell cycle is dominated by S phase, with 82% of all interphase nuclei in the S phase fraction. As development proceeds over the next 60 hours, a gradual decline in S phase cells is proportional to an increase in the number of cells in G1. By the late tailbud stage, 85% of all nuclei are found in the G1 fraction, approximating the cell cycle profile of adult somatic cells. Cell cycle remodeling occurs on schedule even in embryos that have been dissociated into a loose mound of cells which remain in close proximity to one another. However, cells that have been widely separated by manual dispersion do not undergo remodeling. These dispersed cells maintain an S phase‐dominated cell cycle and continue to show patterns of blastula and gastrula gene expression at least 30 hours beyond gastrulation. We conclude that cell cycle remodeling occurs in the absence of an intact embryo but requires the inductive influences associated with a community of cells. © Wiley‐Liss, Inc.
Cyclical morphodynamics of hair bundles in sea anemones: Second messenger pathways
Authors: Mire‐Thibodeaux Patricia , Watson Glen M.
Published: June 2005

Despite lacking sensory organs, sea anemones apparently integrate chemical and mechanical sensory input from prey in the regulation of nematocyst discharge. Exposing anemones to exogenous N‐acetylated sugars induces hair bundles to elongate while shifting nematocyst discharge to lower frequencies matching swimming movements of prey. A pharmacological approach was employed to examine the transduction events involved in the sugar induced “tuning” of anemone hair bundles. Photoactivation of caged cyclic‐AMP (cAMP) induces bundles to elongate to a maximum length by 4 min and subsequently to shorten to near control lengths by 8 min. Continuous stimulation with sugar produces a similar effect with the cycle continuing through at least 20 min. With sugar stimulation, nematocyst discharge into targets vibrating at 5 Hz also follows the same, cyclical pattern. Bundles do not elongate in the combined presence of N‐acetylated sugars and H89, an inhibitor of protein kinase A. Elongated bundles either do not shorten, or rapidly recover from shortening, if caged cAMP is photoactivated 3.5 min after the initiation of sugar stimulation. Furthermore, bundle shortening is blocked by caffeine, an inhibitor of phosphodiesterase, W7, an inhibitor of calmodulin, nifedipine, an inhibitor of certain calcium channels, or cypermethrin, an inhibitor of protein phosphatase 2B (PP2B). Thus, chemodetection of sugars may involve an immediate elevation of intracellular cAMP, leading to an activation of protein kinase A, inducing bundles to elongate. Subsequently, calcium channels may be activated leading to a calcium/calmodulin dependent enhancement of phosphodiesterase and an activation of PP2B, inducing bundles to shorten by degrading cAMP and dephosphorylating proteins. © Wiley‐Liss, Inc.
Ultrastructural changes in micropylar and granulosa cells during in vitro oocyte maturation in the medaka, Oryzias latipes
Authors: Nakashima S. , Iwamatsu T.
Published: June 2005

Ultrastructural changes in micropylar cells during in vitro oogenesis in the medaka, Oryzias latipes, were examined by electron microscopy. In micropylar cells, bundles of microtubules and tonofilaments are well developed by the post‐vitellogenic stage of oogenesis. At the initiation of germinal vesicle breakdown (GVBD), the twisted cytoplasmic protrusion of the enlarged micropylar cell extends to the oocyte surface through the micropylar canal of the chorion. Various kinds of organelles in the cytoplasm of the micropylar cell show a characteristic pattern of distribution. Extensive tonofilaments occupy a large portion of the cytoplasm in the main cell body, while spiraling bundles of both microtubules and tonofilaments are observed along with mitochondria in the cytoplasmic protrusion. About 3 hours after GVBD, the cytoplasmic protrusion begins to shrink and gradually withdraw from the micropylar canal. It has few or no bundles of microtubules and tonofilaments during its withdrawal. The micropylar cell finally becomes oval in shape by 6 hours after the initiation of GVBD as its cytoplasmic protrusion shrinks completely. These observations suggest that these cell organelles are involved in forming, supporting, and/or withdrawing the cytoplasmic protrusion of the micropylar cell. © Wiley‐Liss, Inc.
Distribution of myoplasmic cytoskeletal domains among egg fragments of the ascidian Ciona savignyi: The concentration of deep filamentous lattice in the fragment enriched with muscle determinants
Authors: Marikawa Yusuke
Published: June 2005

The myoplasm of the ascidian egg contains muscle determinants and is composed of myoplasmic cytoskeletal domain (MCD). MCD consists of two interacting parts, a plasma membrane lamina (PML) and a deep filamentous lattice (DFL). We showed that, among the four types of egg fragments that are produced by centrifugation of unfertilized Ciona savignyi eggs, muscle determinants are concentrated in only one type (black fragment) and are virtually absent in the others (clear, brown and red fragments). In this study, to investigate the relationship between MCD and muscle determinants, we compared the distribution of PML and DFL among the egg fragments. Actin filament, which is a component of PML, was found in all fragments. In contrast, p58, which is a protein recognized by an anti‐intermediate filament antibody and is a component of DFL, was highly concentrated in black fragments and excluded from the other three. In addition, pigment granules and mitochondria, both of which are embedded in DFL, were also concentrated in black fragments. Thus, the distribution of muscle deteminants among the egg fragments coincided with that of DFL, supporting the possibility that muscle determinants may be associated with DFL rather than with PML. © 1995 Wiley‐Liss, Inc.
In vitro study of vitellogenesis in the blue crab (Callinectes sapidus): Site and control of vitellin synthesis
Authors: Lee Chi‐Ying , Watson R. Douglas
Published: June 2005

The determine the site of vitellin (Vn) synthesis in the blue crab, Callinectes sapidus, tissues (ovary, hepatopancreas, and gill) from adult female crabs were incubated in vitro with [35S]methionine. Tissue extracts were separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and radiolabeled proteins were visualized by autoradiography: Four radiolabeled ovarian proteins (188, 168, 109, and 86 kDa) comigrated with the subunits of Vn. A Western blot analysis confirmed that these ovarian proteins were the Vn subunits. Proteins in the hepatopancreas and gill were also radiolabeled but were not Vn‐immunoreactive. In vitro incorporation of [35S] methionine into ovarian proteins was inhibited by an extract of eyestalks; the inhibition was dose‐dependent and specific. Autoradiography of the electrophoretically separated ovarian proteins revealed that the eyestalk extract inhibited incorporation of [35S] methionine into numerous proteins, including the Vn subunits. These results suggest that the ovary is a site of Vn synthesis and that the eyestalks contain a factor or factors that directly inhibit the synthesis of Vn and other ovarian proteins. It is anticipated that the suppression of ovarian protein synthesis will be a useful bioassay for blue crab vitellogenesis‐inhibiting hormone. © 1995 Wiley‐Liss, Inc.
Proteins of crustacean exoskeleton: III. Glycoproteins in the Bermuda land crab Gecarcinus lateralis
Authors: Kumari S. Sindhu , Skinner Dorothy M.
Published: June 2005

Chitin and protein are major components of crustacean exoskeletons. In insect cuticles, glycosylation is one of the predominant post‐translational modifications of the proteins. Investigations of glycosylation of crustacean exoskeletal proteins are much more limited. We have used lectins to follow changes in glycosylation of proteins in the exoskeletal layers of the Bermuda land crab Gecarcinus lateralis at selected stages of the intermolt cycle. Proteins extracted from the individual layers during anecdysis and late proecdysis as well as from the layers of exuviae were electrophoresed on sodium dodecyl sulfate (SDS)‐polyacrylamidegels, blotted to polyvinylidene difluoride membranes, and reacted with biotinylated lectins. Seven lectins were tested: concanavalin A (Con A), soybean agglutinin (SBA), wheat germ agglutinin (WGA), Dolichos biflorus agglutinin (DBA), Ulex europaeus agglutinin(UEA I), Ricinus communis agglutinin (RCA120), and peanut agglutinin (PNA). Con A, which binds primarily to mannose residues, produced the strongest signals. Duringanecdysis, most of the binding occurred with protein bands larger than 31 kDa, while in lateproecdysis and in layers from exuviae, small as well as large proteins were bound. N‐glycosidase F digestion of electrotransferred proteins and subsequent treatment with Con A indicated both N‐linked and O‐linked glycosylation. SBA, which binds to both α‐and β‐linked N‐acetylgalactosamine, was the second most reactive lectin, and the number of exoskeletal proteins to which it bound also increased in late proecdysis. Little or no binding of DBA, RCA120, or PNA, which react with α‐linked N‐acetylgalactosamine, indicated that the N‐acetylgalactosamine was β‐linked. The specificity of binding of Con A or SBA was demonstrated by inhibition with methyl‐α‐D‐mannopyranoside and N‐acetyl‐D‐galactosamine, respectively. Binding of UEAI revealed the presence of fucose residues on a few proteins. As the exoskeleton was degraded during proecdysis, protein bands that were not detected by lectin binding during anecdysis were modified in such a way that they became accessible to lectins. © 1995 Wiley‐Liss, Inc.
Proteolytic cleavage of vitellogenin and yolk proteins during vitellogenin uptake and oocyte maturation in barfin flounder (Verasper moseri)
Authors: Matsubara Takahiro , Sawano Keiichi
Published: June 2005

Vitellogenin (Vg) and vitellogenin‐derived yolk proteins of growing oocytes and ovulated eggs were purified and characterized to evaluate structural changes of yolk proteins during oocyte growth and maturation in barfin flounder, Verasper moseri, a marine teleost which lays pelagic eggs. Native circulating vitellogenin, estimated to be a 520 kDa protein using Superose 6 column chromatography, cleaved into the 410 kDa major yolk protein, lipovitellin (Lv), in vitellogenic oocytes. An additional minor yolk protein at 19 kDa in native form, which was immunoreactive to an antiserum raised against Vg, and a highly phosphorylated 38 kDa band of phosvitin (Pv) in SDS‐PAGE with reduction were also identified in vitellogenic oocytes. Analysis of the amino acid composition of the 19 kDa yolk protein showed it to be similar to the β′‐component of egg yolk from salmonid fish. The 410 kDa Lv in vitellogenic oocytes was proteolytically cleaved into an 170 kDa major yolk protein during final oocyte maturation. The close similarity of amino acid composition between the two proteins combined with the results of lipid analysis suggested that the 410 kDa Lv cleaved into two homologous 170 kDa monomeric Lv. Both 19 kDa yolk protein (β′‐component) and Pv became undetectable after oocyte maturation. We propose that the three classes of yolk proteins (Lv, Pv, and β′‐component) are products of Vg cleavage, and that all of them undergo proteolysis again during oocyte maturation. © 1995 Wiley‐Liss, Inc.
External and internal influences on indices of physiological stress: II. Seasonal and size‐related variations in blood composition in free‐living lizards, Sceloporus occidentalis
Authors: Dunlap Kent D.
Published: June 2005

Seasonal changes in blood composition (plasma osmolality, total plasma protein, hematocrit) in two free‐living populations of fence lizards, Sceloporus occidentalis, one living in a very arid environment (Pearblossom, CA) and another in a milder desert (Bend, OR), were analyzed. In this analysis, two features of reptilian physiology and ecology were incorporated: ontogenetic variation in blood composition and seasonal variation in body‐size distribution. The population living in the arid environment, but not the mild environment, exhibited significant seasonal changes in blood composition: mean plasma osmolality increased (345 ± 4 to 356 ± 3 mOsmol/kg) and mean plasma protein (4.19 ± 0.20 to 3.34 ± 0.14 g/dl) and hematocrit decreased (43.8 ± 0.3 to 31.6 ± 0.4) from April to August. These changes suggested that the physiological condition of the California population was affected by seasonal changes in the external environment. However, among individuals, a significant portion of the variation in blood composition was associated with an internal factor, body size. Larger lizards had higher osmolality, total protein, and hematocrit than smaller lizards in all seasons. In addition, the mean body size of active lizards decreased from April to August in California, but not Oregon. Because the body‐size distribution of active lizards in California shifted between seasons, changes in mean population values of these blood parameters probably do not accurately reflect changes that occur within individuals and therefore may be misleading in assessing the physiological consequences of drought. © 1995 Wiley‐Liss, Inc.
Serotonin‐induced parturition in the fingernail clam Sphaerium (Musculium) transversum (Say)
Authors: Fong Peter P. , Warner Marlene
Published: June 2005

Parturition in the freshwater fingernail clam Sphaerium (=Musculium) transversum (Say) was induced by external application of both 10−4 and 10−3 M serotonin [5‐hy‐droxytryptamine (5‐HT)]. 5‐HT induced release of viable juveniles within 30–60 min of application. Parturitions in 5‐HT (10−3 M) occurred sooner and more often than in 5‐HT (10−5 or 10−4 M) or in artificial pond water. The numbers of juveniles per parturition in 5‐HT varied from one to nine. The parturition response to 5‐HT was completely blocked by 10−4 M methiothepin (a vertebrate 5‐HT1/5‐HT2 receptor antagonist) known to bind with high affinity to gastropod 5‐HT receptors and to block 5‐HT‐induced spawning in other freshwater bivalves. However, parturition was not induced by 8‐OH‐DPAT (8‐hydroxy‐dipropylaminotetralin HBr, a vertebrate 5‐HT1A receptor agonist), a potent inducer of spawning in freshwater bivalves. Thus, the pharmacological profile of the 5‐HT receptor(s) mediating parturition in S. transversum may be unlike that mediating spawning in other bivalves. This is the first report of 5‐HT‐induced parturition in any brooding bivalve. © 1995 Wiley‐Liss, Inc.
Integration of photoperiodic and food cues to time changes in reproductive physiology by an opportunistic breeder, the red crossbill, Loxia curvirostra (Aves: Carduelinae)
Authors: Hahn Thomas P.
Published: June 2005

Opportunistic breeders presumably use short‐term cues (e.g., food) instead of photoperiod to time breeding. This view cannot explain regulation of reproductive patterns in one opportunist, the red crossbill (Loxia curvirostra). Captive crossbills held on natural photoperiod, constant temperature, and ad libitum food express cycles of gonadal development, secretion of luteinizing hormone (LH), fat deposition, body mass, hematocrit, and molt. This shows that changing food availability (presumed to drive reproduction in these birds) is not necessary for expression of a seasonal cycle. However, changes in food availability can modulate this seasonal pattern. Reduced food intake attenuates long day induced LH secretion. Furthermore, long day stimulated birds show greater testicular development if shifted from restricted to ad libitum food than if provided ad libitum food continuously. Ad libitum food alone does not stimulate complete reproductive development in winter, when crossbills often breed opportunistically in the wild. Additional stimulation by other factors (e.g., social interactions) is critical at this time. Thus, crossbills regulate their basic annual cycle with photoperiod and superimpose opportunistic responses to supplementary cues (e.g., food and social factors) on this underlying seasonality. This permits crossbills to adjust to both seasonally predictable and unpredictable changes in their environment. © 1995 Wiley‐Liss, Inc.
Mixed finite element analysis of a thermally nonlinear coupled problem
Authors: Zhu Jiang , Loula Abimael F. D.
Published: June 2005

In Loula and Zhou [Comput Appl Math 20 (2001), 321–339], a thermally coupled nonlinear elliptic system modeling a large class of engineering problems was considered, and some mathematical and numerical analyses (C0 Lagrangian finite elements combined with a fixed point algorithm) were given. To continue our work, we propose in this article a mixed method for the potential equation and present the corresponding analyses and numerical implementations. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
A supervised learning method using duality in the artificial neuron model
Authors: Yamada Keiichi , Kuroyanagi Susumu , Iwata Akira
Published: June 2005

In a layered neural network, the error backpropagation method is generally used as the supervised learning procedure for the hidden layer, which cannot be observed from the outside. In order to apply the method, however, the output function of the neuron model must be differentiable. This paper proposes a supervised learning method for the hidden layer neurons in which the teaching signal is calculated for the hidden layer neurons, by utilizing the learning rule for the connection weight and the duality in the output layer neuron. The method is applicable so long as the neuron model contains duality, and it does not require that the output layer neurons or the hidden layer neurons be differentiable. As an example of a case in which the error backpropagation cannot be applied, a perceptron composed of neurons with a step output function is considered. The proposed method is applied, and the learning rule for the whole network is constructed. The XOR problem was actually learned by the network, and the same learning success rate was obtained as in the error backpropagation method for a perceptron composed of neurons with a sigmoid output function. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(9): 34–42, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20206
Pulsed neural networks based on delta‐sigma modulation with GHA learning rule and their hardware implementation
Authors: Murahashi Yoshimitsu , Hotta Hirohisa , Doki Shinji , Okuma Shigeru
Published: June 2005

In order to achieve fast parallel processing operation by a neural network, it is desirable to implement all neurons in parallel in hardware rather than to realize operation by serial operation in software. The authors have proposed a pulsed neural network based on ΔΣ modulation which is suited to the hardware implementation of digital circuits. The proposed neural network can be realized on a small circuit scale, since the variable can be represented by a ΔΣ‐modulated 1‐bit pulse signal. Highly accurate operation can be realized even though only 1 bit is used. This paper proposes a hardware implementation of the above neural network. A neural network with built‐in GHA learning rule is hardware implemented on an FPGA, and its operation is investigated. The proposed neural network and CPU are implemented on an FPGA and are compared in terms of the number of bits that can be processed in unit time per unit of circuit scale. The proposed scheme achieved an evaluation score 200 times as great as a software realization on a CPU. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(9): 14–24, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20235
The incidence of malformations in Birmingham, England, 1950–1959
Authors: Leck Ian , Record R. G. , McKeown Thomas , Edwards J. H.
Published: June 2005

An attempt was made to identify all malformations among the 190,236 births that occurred in Birmingham in the ten years 1950–59. This was done by examining (a) obstetric summaries completed either by hospital staff or, for domiciliary births, by midwives; and (b) notifications of stillbirths, certificates of cause of death, and necropsy reports of infants who died in the first two weeks. The number of malformed individuals found was 3637 (19.1 per 1000 births).

A more complete ascertainment was achieved in respect of the 1950–54 births by following the children to the age of six years and searching hospital records, death registers, necropsy reports, and the City's Public Health and Education Departments' registers of the physically handicapped and of the mentally subnormal. By these methods 2527 malformed individuals in a population of 94,474 births were identified (26.7 per 1000). The malformation rate was higher for hospital births than for children born at home; the difference was due to selection of patients for hospital delivery and not to inferior recording of domiciliary births.

Details of all malformations recorded are given in table 6 and in the appendix. The most frequent malformations, each with an incidence of at least one per 1000 births, were clubfoot, cardiac anomalies, anencephalus, spina bifida, clefts of lip and palate, Down's disease, hydrocephalus, and polydactyly. These accounted for three–fifths of the total. Combinations of several malformations in the same individual occurred much more frequently than if association between malformations were fortuitous. Apart from the well–known associations of cardiac malformations with Down's disease and clubfoot with spina bifida and anencephalus, the most frequent combinations noted were cardiac defects with clubfoot and with clefts of lip and palate, and clubfoot with hydronephrosis and with reduction deformities of the upper limb.
Studies of vitamin A‐induced teratogenesis: Effects on embryonic mesenchyme and epithelium, and on incorporation of H3‐thymidine
Authors: Kochhar D. M.
Published: June 2005

Some aspects of tissue differentiation were studied in 13‐day rat embryos after vitamin A treatment of their mothers on days 10, 11, and 12 of gestation. Severely affected embryos showed extensive growth retardation. Inhibition of cell proliferation, assumed from a decreased rate of H3‐thymidine uptake, was found in the liver, loose mesenchyme of the cephalic region, posterior region of the palatine shelves, trigeminal nucleus, and in some areas of the skin. Other tissues investigated showed no inhibition.

Development of the face in these embryos was characterized by the appearance of defects in the mesoderm of the maxillary process and in the oral epithelium. It is suggested that palatal and dental abnormalities of vitamin A‐treated embryos arise because of some initial changes in the epithelium, which subsequently lead to a disrupted epithelial‐mesodermal relation in this region, so essential for normal development.

Some physicochemical properties of vitamin A, such as its high surface activity and its effect on membrane permeability, enable it to have widespread effects. Information about the importance of these phenomena in the developing embryo must await further elucidation of the mechanism of action of vitamin A in biological organisms in general.
Incorporation and utilization of radioglucose in the fish embryo Oryzias latipes during teratogenesis
Authors: Smithberg Morris , Dixit Padmakar K.
Published: June 2005

Malformations have been produced in fish embryos of Oryzias latipes following exposure to the sulfonylurea sodium tolbutamide during day 1 of development (Smithberg '62).

Our present objectives were to determine (1) whether glucose 1‐14C would be differentially incorporated by embryos after drug treatment; and (2) whether the incorporated radioglucose would be converted to glycogen and lipid following drug treatment Total glycogen and total lipid were also measured in a normal and teratogenic environment.

We confirmed the results of others that total glycogen decreased during the first three days of normal development and then slowly regained its initial level. During treatment with tolbutamide significantly more glycogen was utilized during the first three days. Total lipid tended to be lower in embryos after 48 hours of treatment compared to corresponding control embryos.

Incorporation of radioglucose was inhibited by the drug, and the degree of inhibition varied with its concentration, although the conversion of glucose (or its products) into glycogen and lipid was not different in control and experimental embryos. It is suggested that tolbutamide may affect the permeability of the fish embryo membrane.
Teratogenic effects of aminopterin in sheep
Authors: James Lynn F. , Keeler Richard F.
Published: June 2005

Sheep were given subcutaneous injections of aminopterin at different times and for different intervals during gestation. Congenital malformations occurred after treatment at all periods. The principal malformations observed were rotational and flexing deformities of the appendicular skeleton, kyphosis, scoliosis, torticollis, aplasia of the mandible, overflexion of the carpal joint, hypermobility and dorsiflexion of the hock and stifle joints, and relaxation of the fetlock joints. Aplastic ears were also noted.
Abnormal development of eyes in mice homozygous for the fidget gene
Authors: Konyukhov B. V. , Vakhrusheva M. P.
Published: June 2005

The eyes of 17‐, 24‐, 28‐, and 31‐somite and 10‐ to 16‐day prenatal, newborn, and 6‐month‐old fidget (fi/fi) mice were studied. The present study showed that the eye abnormalities in fi/fi mice are due to growth retardation of the optic vesicle. In fi/fi embryos the volume of the optic vesicle and its mitotic index were considerably below normal. The reduced growth rate of the optic vesicle led to its delayed contact with the ectoderm and prevented normal lens induction. The lens often did not bud off from the surface ectoderm. In some cases the greatly reduced growth rate of the optic vesicle prevented its contact with the ectoderm and resulted in aphakia. Anophthalmia was also observed, which was caused by the arrest of eye development at the early optic‐vesicle stage. The mitotic index in the wall of myelencephalon and the ventral half of prosencephalon wall was considerably lower than normal. This suggests that the anomalies of the eye and the labyrinth in fi/fi mice are evidently due to an antecedent developmental abnormality of the brain.