bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salt loading stimulates secretion by the lingual salt glands in unrestrained Crocodylus porosus
Authors: Taylor Greg C. , Franklin Craig E. , Grigg Gordon C. 
Published: June 2005

AbstractIn previous studies, the lingual salt glands of crocodiles have failed to secrete in response to a salt load. This is unlike salt glands in other reptiles and in birds, and it has led to some doubt about the extent to which the salt glands in crocodiles are of functional importance.Believing that the failure to secrete may be associated with the artificial restraint associated with measurement, or with the removal of study animals from the water, we designed and built an electronic sensor which would monitor secretions from the salt glands of crocodiles while they were in water and undisturbed.Under these conditions, the salt glands were observed to secrete spontaneously. Under salt loading, delivered via a femoral vein cannula, there was a rapid production of secretion from the glands. Secretion was stimulated by methacholine and acetylcholine chlorides also. The results support the view that the lingual salt glands in crocodilians are stimulated by a salt load and that previous attempts to demonstrate this may have been influenced by the experimental conditions. © 1995 Wiley‐Liss, Inc.
Inhibitory action of hypoxanthine on meiotic resumption of denuded pig follicular oocytes in vitro
Authors: Miyano Takashi , Ebihara Misa , Goto Yuri , Hirao Yuji , Nagai Takashi , Kato Seishiro 
Published: June 2005

AbstractThe present study was conducted to investigate the direct action of hypoxanthine, which has been reported to be present in pig follicular fluid, on spontaneous meiotic resumption of pig denuded oocytes in vitro. No oocytes, which were surrounded by a cumulus and some membrana granulosa cells directly adjacent to it from healthy antral follicles, underwent germinal vesicle breakdown (GVBD) when they were cultured in serum‐supplemented 199 with or without 4 mM hypoxanthine. On the other hand, 81% of denuded oocytes prepared from such cumulus‐oocyte‐granulosa cell complexes showed GVBD after 24 h of culture. Hypoxanthine inhibited significantly this spontaneous resumption of meiosis in denuded oocytes. The inhibitory action of hypoxanthine was dose dependent at concentrations of 1–6 mM and was reversible following subsequent culture of the oocytes in hypoxanthine‐free medium. However, premature chromosome condensation was observed in oocytes cultured in hypoxanthine‐supplemented medium, and the oocytes released from the influence of hypoxanthine completed GVBD and reached the second metaphase slightly faster than those freshly isolated from the follicle. These results suggest that hypoxanthine inhibits spontaneous meiotic resumption of pig oocytes in vitro. However, the inhibitory action of hypoxanthine does not prevent all events involved in GVBD from occurring. © 1995 Wiley‐Liss, Inc.
Calcium oscillations and calcium waves coordinate rhythmic contractile activity within the stellate cell layer of medaka fish embryos
Authors: Simon Joanne Z. , Cooper Mark S. 
Published: June 2005

AbstractDuring gastrulation and body axis formation in medaka (Oryzias latipes) fish embryos, rhythmic contraction waves sweep across a tissue sheet known as the periderm, which covers both the developing embryo and its associated yolk cell. Cope et al. ([1990] J. Exp. Zool., 254:270–275) have found that these contractions are generated by a layer of stellate‐shaped cells which is closely apposed to the inner surface of the periderm. In this paper, we show that rhythmic contractions in the stellate cell layer are correlated with elevations of intracellular [Ca2+]. Medaka periderms were first explanted and secured to microscope coverslips using a modified plasma clot culture technique. The explants were then loaded with the calcium indicator dye Fluo‐3AM and observed with time‐lapse epifluorescence confocal microscopy. Rises of intracellular [Ca2+] were observed to propagate from cell to cell in the stellate cell layer, in the form of intercellular waves. After a latency of a few seconds, a coordinated contraction within the stellate cell layer ensued. Rhythmic Ca spikes were also observed within individual stellate cells. In many cases, rises of intracellular [Ca2+] preceded cellular contraction in these individual cells by several seconds. The Ca oscillations and Ca waves that occur in medaka stellate cells represent one of the earliest expressions of Ca‐based excitability and contractility within the blastoderm of post‐fertilization vertebrate embryos. © 1995 Wiley‐Liss, Inc.
Allozymic and cytological evidence for hemiclonal, all‐paternal, and mosaic offspring of the hybridogenetic stick insect Bacillus rossius‐grandii grandii
Authors: Tinti Fausto , Scali Valerio 
Published: June 2005

AbstractBacillus hybridogens represent the first example of hemiclonal reproduction among invertebrates and they were analyzed in the present study for comparison with vertebrate hybridogenetic complexes (Poeciliopsis and Rana). Experimental crosses of southeastern hybridogenetic B. rossius‐grandii grandii females with both the parental species and hybrid males were carried out to test the reproductive potential of hybridogens. Allozyme and chromosome markers indicated that hemiclonal females actually reproduced in a variety of ways. Hybridogenesis was the most common and the rossius unassorted haploset was passed to the progeny while the grandii haploset was discarded during meiosis and replaced by that of the fathering male. Andro‐genesis, which was much rarer, led to the production of two types of all‐paternal offspring: unipa‐rental progeny of both sexes and all‐male progeny with the same allozyme and chromosome structure as their father. Mosaics of two kinds were also produced: the “h + h” type, with two different hybridogenetic cell lines; and the “h + a” type, with one hybridogenetic and one androgenetic cell line. Mosaics evolved into intersexes when their cell lines were sexually discordant. Among the evolutionary outcomes of this wide array of reproductive ways seems to be a shift from hemiclonality to clonality. This possibility is supported by the well‐established parthenogen B. whitei and the occasional production of rare invariant specimens from the northwestern hybridogenetic form B. rossius‐grandii benazzii. Bacillus and other unisexuals provide evidence of numerous reproductive interactions between hybrids and their bisexual relatives: the occurrence of such interactions may play an important role in the persistence, diversification and evolution of unisexuals. © 1995 Wiley‐Liss, Inc.
Effect of hypothyroidism induced by propylthiouracil and thiourea on male and female reproductive systems of neonatal mice
Authors: Chan W. Y. , Ng T. B. 
Published: June 2005

AbstractThe effect of hypothyroidism induced by 6‐propyl‐2‐thiouracil (PTU) or thiourea (TU) on the development of the reproductive system in male and female neonatal ICR mice was investigated. PTU or TU was injected subcutaneously into experimental animals from postnatal day 1 (PD1) onward. The histological changes of the reproductive organs, formation of ovarian follicles, and spermatogenesis were examined on PD 14, 21, and 28, and the fertility of the hypothyroid mice in adulthood was followed. It was found that PTU or TU treatment did not produce an effect on the histology of the neonatal uterus and oviduct. In contrast, the drugs induced a decrease in the number of primordial follicles, multilaminar follicles, and Graafian follicles in the ovary. The number of follicles with degenerated follicular cells was increased. In the testis both PTU and TU treatments brought about a decrease in the number of seminiferous tubules with developing spermatids although the mean diameter of seminiferous tubules and the histology of the testis, epididymis, seminal vesicle, and coagulating gland was unaffected. The mating between hypothyroid females and euthyroid males and that between hypothyroid males and euthyroid females were normal with regard to the pregnancy rate, litter size, and sex ratio of offspring. The somatic growth of the resulting offspring was normal. It is concluded that the retarding effect on ovarian and testicular development in mice during neonatal period was not serious enough to adversely affect reproduction in the hypothyroid animals. © 1995 Wiley‐Liss, Inc.
Mirror‐image duplication of the primary axis and heart in Xenopus embryos by the overexpression of Msx‐1 gene
Authors: Chen Yiping , Solursh Michael 
Published: June 2005

AbstractThe Msx‐1 gene (formerly known as Hox‐7) is a member of a discrete subclass of homeobox‐containing genes. Examination of the expression pattern of Msx‐1 in murine and avian embryos suggests that this gene may be involved in the regionalization of the medio‐lateral axis during earlier development. We have examined the possible functions of Xenopus Msx‐1 during early Xenopus embryonic development by overexpression of the Msx‐1 gene. Overexpression of Msx‐1 causes a left‐right mirror‐image duplication of primary axial structures, including notochord, neural tube, somites, suckers, and foregut. The embryonic developing heart is also mirrorimage duplicated, including looping directions and polarity. These results indicate that Msx‐1 may be involved in the mesoderm formation as well as left‐right patterning in the early Xenopus embryonic development. © 1995 Wiley‐Liss, Inc.
Cytogenetic studies on diploid and triploid oogenesis in interspecific hybrid fish between Oryzias latipes and O. curvinotus
Authors: Kurita Jun , Oshiro Takashi , Takashima Fumio , Sakaizumi Mitsuru 
Published: June 2005

AbstractInterspecific hybrid females produced from reciprocal crosses between Oryzias latipes and O. curvinotus show reduced fertility, but they do lay eggs. When fertilized by sperm from one of the parental species, such eggs developed into triploid males and females. To confirm the ploidy of the eggs spawned by the hybrid females we examined the karyotypes of backcross and gynogenetic offspring. The karyotype of the China‐West Korean medaka, O. latipes sinensis, was 2n, with 46 chromosomes, including a pair of “large” metacentrics, whereas O. curvinotus had 2n, 48, without such a chromosome pair. F1 hybrids had a karyotype 2n, 47, with one large chromosome. When the hybrid females were backcrossed to O.l. sinensis, the offspring had a karyotype of 3n, 70, with two large chromosomes. By contrast, when backcrossed to O. curvinotus, the progeny of the hybrid females had a karyotype of 3n, 71, with one large chromosome. After gynogenetic treatment with UV‐irradiated sperm of rainbow trout, the eggs spawned by the hybrid females developed into diploid (2n, 47) fish with one large metacentric chromosome. These results indicate that the hybrid females spawn unreduced diploid eggs with one complete chromosome set for both parental species. A triploid female, in contrast to the diploid hybrid females, spawned eggs with reduced chromosome number, giving rise to hyperdiploid embryos when fertilized by sperm. Transplantation of scales and electrophoretic analysis of proteins indicated that a hybrid female and her gynogenetic offspring can be regarded as “clones” with identical sets of chromosomes. © 1995 Wiley‐Liss, Inc.
Physiology of atympanate tibial organs in forelegs and midlegs of the cave‐living Ensifera, Troglophilus neglectus (Raphidophoridae, Gryllacridoidea)
Authors: Cokl Andrej , Kalmring Klaus , Rössler Wolfgang 
Published: June 2005

AbstractThe complex tibial organs of the Ensiferan species Troglophilus neglectus (Raphidophoridae, Gryllacridoidea) do not differ significantly in their morphology in all six legs. They consist of a normal developed subgenual organ and an intermediate organ (when compared with the conditions in tettigoniids). Physiologically, the receptor cells of the complex tibial organs of the fore‐ and midlegs could be grouped into 11 functional types. Four of these types belong probably to the intermediate organ; the cells of these types respond to frequencies from 700 Hz to 2,000 Hz to both substrate‐ and airborne sound but are more sensitive to the former. The remaining seven types belong to the subgenual organ. Their receptors are tuned to stimuli within frequencies ranging from 200 Hz to 700 Hz. The classification into different functional types and their attribution to the two receptor organs were derived from a comparison with the physiological properties of the receptors of the complex tibial organs in the midlegs of tettigoniids. In the Troglophilinae the subgenual and intermediate organs are structurally very similar to those of the midleg receptor organs of tettigoniids; only the most distal part of the intermediate organ and the crista acoustica is missing. Consistent with the similarities in the proximal part of the receptor complex, the receptor cells of the subgenual and intermediate organs show similar physiological characteristics. © 1995 Wiley‐Liss, Inc.
Heat flow is measurable from Artemia franciscana embryos under anoxia
Authors: Hand Steven C. 
Published: June 2005

AbstractA recent report has concluded that heat flow under anoxia from encysted embryos of the brine shrimp Artemia is unmeasurable (Hontoria et al. [1993] J. Exp. Biol., 178:149–159). This observation contrasts with two earlier communications that have reported low but measurable energy flow from these gastrulae (Hand and Gnaiger [1988] Science, 239:1425–1427; Hand [1990] J. Comp. Physiol. [B], 160:357–363). In order to re‐examine this issue, up to 20 g wet mass of embryos was loaded per experiment into sealed ampoules (25‐ to 50‐fold more tissue than in previous studies) and calorimetric analyses were conducted. Even after 50–60 h, a clearly measurable heat dissipation was recorded from these anoxic embryos (0.0128 ± 0.0007 mW·g dry mass−1; ± 1 SE, n =6). The results confirm the presence of measurable heat flow under anoxia. The rate of heat dissipation measured in this study is at the limit of detection for the instrument used by Hontoria et al. ([1993] J. Exp. Biol., 178:149–159). A second important issue is whether any of the low heat flow under anoxia is associated with processes involving ATP turnover, a point that is evaluated in this study but that remains unresolved. However, calculations suggest that macromolecular degradation may explain a significant portion of the anoxic heat flow. © 1995 Wiley‐Liss, Inc.
Sound production in Pituophis melanoleucus (Serpentes: Colubridae) with the first description of a vocal cord in snakes
Authors: Young Bruce A. , Sheft Stan , Yost William 
Published: June 2005

AbstractThe pine, gopher, or bull snake (Pituophis melanoleucus) makes two different defensive sounds. Hisses are characterized by lack of frequency and amplitude modulation; bellows have a brief initial period of high‐amplitude, broad‐frequency sound followed by a longer period of lower‐amplitude, constant‐frequency sound. Both defensive sounds contain distinct harmonic elements. The modulation and harmonic nature of these sounds seems to be unique among snakes. The larynx of Pituophis is unusual in having an epiglottal keel, a dorsal expansion of the cricoid cartilage, previously proposed to contribute to sound production; however, this study shows that it plays only a small role in increasing the amplitude of bellows. Within the larynx of Pituophis is a “vocal cord,” the laryngeal septum, which is a flexible, horizontal shelf of tissue that divides the anterior portion of the larynx. Removal of the laryngeal septum alters the defensive sounds and eliminates their harmonic elements. The laryngeal septum is unique among previously described vertebrate vocal cords or folds because it is supported by the cricoid (as opposed to arytenoid) cartilage and is a single (as opposed to bilaterally paired) structure. © 1995 Wiley‐Liss, Inc.
Tensegrity model of pattern formation during cytokinesis of a ciliate, Paramecium: Effects of an inhibitor of phosphorylation, 6‐dimethylaminopurine, and of adenine
Authors: Kaczanowska J. , Iftode F. , Jeanmaire‐Wolf R. , Clérot J.‐C. , Kiersnowska M. , Adoutte A. 
Published: June 2005

AbstractDuring cytokinesis of the ciliate Paramecium, the two oral apparatuses (OAs), localized close to the fission line, are displaced to a mid‐region of daughter cells by a tearing off of the OAs and adjacent cortices from the fission line and their subsequent movement toward the poles of the dividing cell. Two possible mechanisms for this displacement were examined: 1) a mechanism whereby the contraction of the fission line in the vicinity of OAs brings about the change of configuration of the adjacent cortices and subsequent displacement of OAs and 2) a mechanism whereby programmed transient depolymerization of the inner cytoskeletal contractile infraciliary lattice in the vicinity of OAs acts as a motive force for displacement of the OAs, together with the most superficial outer lattice of the cytoskeleton which does not disassemble. Our working hypotheses were based on observations on the behavior of the outer lattice, where the infraciliary lattice disintegrates and the fission line assembles.To study the mechanics of pattern formation during cytokinesis of Paramecium, morphogenesis was followed in the presence of an inhibitor of phosphorylation, 6‐dimethylaminopurine (6‐DMAP), and of adenine, which prevented disassembly of the inner lattice and arrested cytokinesis and dislocation of OAs. Nearly all defects in morphogenesis were correlated with failure of the infraciliary lattice to disassemble and failure of the fission line to assemble. It appears that the superficial cortical structures and the contractile infraciliary lattice represent a tensegrity model of morphogenesis during cytokinesis in Paramecium. © 1995 Wiley‐Liss, Inc.
Neural gene therapy for inherited diseases with mental retardation: Principles and prospects
Authors: Schuchman Edward H. , Ioannou Yiannis A. , Rattazzi Mario C. , Desnick Robert J. 
Published: June 2005

AbstractGene therapy for inborn errors of metabolism that cause mental retardation remains a major challenge to gene therapists. In general, such disorders can be divided into two categories: those in which the primary site of pathology resides outside of the central nervous system (CNS), leading to the accumulation of toxic compounds that cross the blood‐brain barrier and cause neurologic dysfunction, and those in which the primary site of pathology resides within the neurons of the CNS. We focus on the strategies and prospects for treating the latter group of diseases, which require delivery of therapeutic genes or gene products to the CNS. Both ex vivo and in vivo approaches can be used. Among the ex vivo strategies, transplanted, genetically corrected hematopoietic stem cells obtained from a patient can enter the CNS and establish microglia within the brain that then secrete therapeutic proteins. Alternatively, neural cells such as oligodendrocytes or astrocytes can be obtained by brain biopsy, genetically corrected in the laboratory using viral or nonviral vectors, then autologously transplanted back into patients for migration and secretion of the therapeutic gene products. Among the in vivo delivery techniques, direct stereotaxic injection of therapeutic gene constructs can be used to correct a metabolic abnormality in a specific region. Intracarotid injection of therapeutic genes coupled with transient disruption of the blood brain barrier could also be used to obtain global delivery. Various approaches to the treatment of inborn errors of metabolism with mental retardation can be envisioned. We discuss each of the major gene delivery systems and related therapeutic strategies. © 1995 Wiley‐Liss, Inc.
Phenylketonuria: A model for hepatic gene therapy
Authors: Fang Bingliang , Eisensmith Randy C. , Woo Savio L. C. 
Published: June 2005

AbstractClassical phenylketonuria (PKU; Mckusick MIM Cat 261600) is an autosomal recessive disorder caused by a deficiency of hepatic phenylalanine hydroxylase (phenylalanine 4‐monooxygenase; PAH; EC 1.14.16.1). The hyperphenylalinemia and mental retardation typical of this disease can be greatly reduced or prevented though the institution, early in life, of a low‐phenylalanine diet. However, the effectiveness of dietary therapy is often limited by poor compliance, especially by adolescents or young adults. This can lead to declines in neuropsychological function. The potential of somatic gene therapy for the treatment of PKU is therefore worth exploring. We discuss three different vector systems. Recombinant retroviral vectors and DNA/protein complexes can efficiently transduce PAH‐ deficient hepatocytes in vitro, but their present application is limited by their low transduction efficiency in vivo. In contrast, infusing a recombinant adenoviral vector expressing the human PAH cDNA into the portal circulation of PAH‐deficient mice restores 10%‐80% of normal hepatic PAH activity and completely normalizes serum phenylalanine levels. At present, this effect is transient and readministration has no further effect. However, this result suggests that PKU and other monogenic hepatic deficiencies can be completely corrected by somatic gene therapy when more persistent vectors are developed. © 1995 Wiley‐Liss, Inc.
Rodent models of mental retardation: Self‐injury, aberrant behavior, and stress
Authors: Tessel Richard E. , Schroeder Stephen R. , Stodgell Christopher J. , Loupe Pippa S. 
Published: June 2005

AbstractThis paper reviews the research on three animal models related to self‐injurious behavior (SIB), stereotypy, and aggression and their susceptibility to stress. These studies support the importance of stress and differences in organic dysfunction in the etiology, maintenance, and topography of SIB and their relationship to stereotypy and aggression. Several organic risk factors associated with mental retardation also increase the susceptibility to manifestation of SIB and related behaviors. © 1995 Wiley‐Liss, Inc.
Analysis of FMRP, the protein deficient in fragile X syndrome
Authors: Small Kersten , Warren Stephen T. 
Published: June 2005

AbstractFragile X syndrome results from a massive trinucleotide repeat expansion in the 5′ untranslated region of the gene FMR1. Methylation of FMR1 occurs as a result of this expansion, causing transcriptional silencing. Therefore, the absence of FMR protein (FMRP) appears to result in fragile X syndrome. Characterization of the gene and its expression, as well as the cellular localization and functional properties of the protein, provide insight into how the absence of FMRP results in mental retardation and the related phenotype. Alternative splicing of FMR1 transcripts leads to protein isoforms and suggests that this cell is functionally diverse. Among vertebrates, FMRP is highly conserved at the amino acid level and localizes mainly to the cytoplasm. The presence of two protein sequence motifs, the RGG box and the KH domain, suggests that FMRP is an RNA‐binding protein. Direct experimentation shows that FMRP is capable of binding its own RNA in vitro, as well as a subset of brain‐derived messages. Further understanding of how these interactions take place and identification of those genes having messages that interact will provide insight into the mechanisms of cognitive function in humans. © 1995 Wiley‐Liss, Inc.