bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histological process and dynamics of germ cell degeneration in pejerrey Odontesthes bonariensis larvae and juveniles during exposure to warm water
Authors: Ito Lauro Satoru , Yamashita Michiaki , Strüssmann Carlos Augusto 
Published: May 2003

AbstractElevated temperature causes degeneration and disappearance of the germ cells in the males of scrotal mammals. It was recently shown that heat‐induced germ cell degeneration occurs also in fish but, unlike in mammals, it occurs not only in males but also in females. The purpose of this study was to clarify the histological process and dynamics of heat‐induced germ cell disappearance in pejerrey Odontesthes bonariensis larvae and juveniles. Monosex and mixed‐sex fish produced by thermal manipulation of sex (temperature‐dependent sex determination) were subjected to 29°C for periods between 1 and 12 weeks, and used to analyze, by histological methods, the changes in gonadal size and the number of normal and degenerating germ cells. Groups exposed to 29°C for 8–12 weeks were subsequently transferred to 24°C to verify if any gonadal damage would be permanent. Germ cell degeneration, histo‐logically characterized by nuclear pyknosis or eosinophilia and cytoplasmic eosinophilia, was observed with increasing frequency at higher temperatures (29>24> 17°C) and more in males than in females. Clear degenerative changes in the germinal epithelium usually began within one week of exposure to 29°C and appeared clearer in females than in males. Complete loss of germ cells was observed only in individuals exposed for periods of 8–12 weeks to 29°C but no treatment produced 100% sterile fish. Germ cells that remained in the gonads after exposure to 29°C retained the capacity to rapidly recolonize germ cell‐depleted areas, suggesting that the associated somatic cells in the gonads are little or not affected by this temperature. J. Exp. Zool. 297A:169–179, 2003. © 2003 Wiley‐Liss, Inc.
Application of artificial insemination technique to eupyrene and/or apyrene sperm in Bombyx mori
Authors: Sahara Ken , Takemura Yoko 
Published: May 2003

AbstractThe silkworm, Bombyx mori, has a dimorphic sperm system. The eupyrene sperm is the sperm to fertilize eggs and the apyrene sperm plays a crucial role for assisting fertilization. Heat‐treated (33°C for 96h) Daizo (DH) males, one of the strains in the silkworm, produce only eupyrene sperm, while in triploid males only apyrene sperm are functional. Though both types of males are found to be sterile, double copulation of the two males with a single female greatly increases fertility. Here we examined the fertilizing ability of eupyrene and apyrene sperm by means of an artificial insemination technique previously established in B. mori. Neither the eupyrene sperm collected from DH males, nor the apyrene sperm from triploid males have the ability to fertilize eggs. Artificial insemination with the mixture of eupyrene and apyrene sperm leveled up the frequency of fertilized eggs to more than 80%. When cryopreserved DH sperm (eupyrene sperm) were subjected to the same experiment, more than 95% fertilized eggs were obtained. These results confirmed that apyrene sperm play an important and indispensable role in fertilization in B. mori. Separate collection of functional eupyrene sperm and functional apyrene sperm and success of fertilization by means of the artificial insemination technique are applicable for further studies to elucidate the function of apyrene sperm. J. Exp. Zool. 297A:196–200, 2003. © 2003 Wiley‐Liss, Inc.
Detailed lipid analysis of yolk platelets of amphibian (Bufo arenarum) oocytes
Authors: Buschiazzo Jorgelina , Bruzzone Ariana , Alonso Telma Susana 
Published: May 2003

AbstractYolk platelets, the principal components of amphibian oocytes, have been generally considered as material reservoirs. Their biochemical composition and function during oogenesis and early development have not been fully elucidated. The aim of this study was to carry out a lipidic characterization of yolk platelets from full‐grown Bufo arenarum oocytes. Ovarian oocytes were manually obtained and the subcellular fraction was isolated by centrifugation at low velocity. Lipids were separated by thin‐layer chromatography. For compositional analysis, they were derived by methanolysis, being identified and quantified in a gas‐liquid chromatograph. Phospholipid content indicates that phosphatidylcholine and phosphatidylethanolamine are the main phospholipids followed by phosphatidylinositol, sphingomyelin, phosphatidylserine, and phosphatidic acid. Phospholipidic profile is similar to that in whole oocytes except for the absence of diphosphatidylglycerol in yolk platelets. Oleic, palmitic, and linoleic acids are the main fatty acids in phosphatidylcholine, and oleic acid is the principal one in phosphatidylethanolamine. In phosphatidic acid, palmitic, estearic, palmitoleic, and oleic acids represent 68 mol% of the total acyl groups. Phosphatidylinositol, enriched in arachidonic acid, is the most unsaturated phospholipid while sphingomyelin shows the lowest unsaturation index. The acyl group distribution in triacylglycerols is similar when yolk platelets and whole oocytes are compared. Polar and neutral lipids of yolk platelets determine the lipidic profile of the whole oocyte. The presence of unusual fatty acids as 14:0, 15:0, 15:1, 17:0, and 17:1 in phospholipids and triacylglycerols may indicate an oxidation mechanism different from β‐oxidation in yolk platelets and/or a structural and functional relation with mitochondria. Given that yolk platelets in amphibian oocytes may act in a dynamic fashion in development, their role should be reconsidered. J. Exp. Zool. 297A:189–195, 2003. © 2003 Wiley‐Liss, Inc.
Morphology and escape performance of tiger salamander larvae (Ambystoma tigrinum mavortium)
Authors: Fitzpatrick Benjamin M , Benard Michael F. , Fordyce James A. 
Published: May 2003

AbstractThe ability of an individual to escape predators is an important component of fitness. Several adaptive explanations of body shape variation in amphibians hypothesize relationships between swimming performance and morphology, but these ideas have rarely been tested. Here we investigate bivariate and multivariate relationships between natural variation in morphology and performance. We used high‐speed video to examine fast‐starts associated with escape responses in small tiger salamander larvae (Ambystoma tigrinum). Our results indicate that performance is influenced by interactions among aspects of morphology, physiology, and behavior. Relationships between morphometric variables and velocity could be detected with multivariate, but not bivariate statistical analyses. In particular, relationships between morphology and velocity depend on tail beat frequency (potentially a measure of effort or vigor). Relationships between morphology and acceleration were detected with bivariate analyses, but multivariate analysis suggests that acceleration performance, too, depends on interactions between morphology and tail beat frequency. We found a positive relationship between tail area and propulsive performance, which supports adaptive interpretations of variation in larval tail shape within and between amphibian species. J. Exp. Zool. 297A:147–159, 2003. © 2003 Wiley‐Liss, Inc.
Melatonin enhances the sensitivity of circadian pacemakers to light in the nocturnal field mouse Mus booduga
Authors: Sharma Vijay Kumar , Chidambaram R. , Yadunandam A. Kasin 
Published: May 2003

AbstractThe effect of exogenous melatonin (1 mg/kg) on light pulse (LP) induced phase shifts of the circadian locomotor activity rhythm was studied in the nocturnal field mouse Mus booduga. Three phase response curves (PRCs: LP, control, and experimental) were constructed to study the effect of co‐administration of light and melatonin at various circadian times (CTs). The LP PRC was constructed by exposing animals free‐running in constant darkness (DD) to LPs of 100–lux intensity and 15–min duration, at various CTs. The control and experimental PRCs were constructed by using a single injection of either 50% DMSO or melatonin (1 mg/kg dissolved in 50% DMSO), respectively, administered 5 min before LPs, to animals free‐running in DD. A single dose of melatonin significantly modified the waveform of the LP PRC. The experimental PRC had significantly larger areas under advance and delay regions of the PRC compared to the control PRC. This was also confirmed when the phase shifts obtained at various CTs were compared between the three PRCs. The phase delays at three phases (CT12, CT14, and CT16) of the experimental PRCs were significantly greater than those of the control and the LP PRCs. Based on these results we conclude that phase shifting effects of melatonin and light add up to produce larger responses. J. Exp. Zool. 297A:160–168, 2003. © 2003 Wiley‐Liss, Inc.
Gastropod ontogenetic torsion: Developmental remnants of an ancient evolutionary change in body plan
Authors: Page Louise R. 
Published: May 2003

AbstractA dramatic morphogenetic movement (‘ontogenetic torsion’) during the development of gastropods has been proposed as a recapitulation of the original developmental departure that established the novel gastropod body plan. Nevertheless, speculative literature about ontogenetic torsion and its evolutionary significance has far outstripped empirical observations and recent results suggest that the developmental process may be somewhat different than the traditional description. I used scanning electron microscopy, immunohistochemistry, phalloidin labeling, and histological sections to monitor displacements of five components of the visceropallium with respect to axial coordinates of the cephalopodium in developing embryos of the caenogastropod, Trichotropis cancellata. Embryos of this species achieve a transient stage of anatomical organization that also arises during development of a vetigastropod (Haliotis kamtschatkana), although morphogenetic processes that generate this stage are different in these two species. At the stage of similarity, the embryonic shell has achieved its definitive orientation with respect to the cephalopodium, but the developing mantle cavity, sensory osphradium, and anus are confined to the right side. I also show that this stage of anatomical organization is recognizable during the development of other gastropods, which collectively represent three major gastropod clades. I propose that ontogenetic torsion should be viewed as a conserved stage of anatomical organization during development, rather than a conserved process of 180° rotation between the visceropallium and cephalopodium. The results lead to the suggestion that the mantle cavity of extant gastropods evolved by enlargement of the right side of the mantle cavity in a monoplacophoran‐like ancestor. Under this interpretation, there is no need for a hypothetical pre‐gastropod with a mantle cavity that was restricted to the posterior end. J Exp. Zool (Mol. Dev. Evol.) 297B:11–26, 2003. © 2003 Wiley‐Liss, Inc.
Phylogenetic considerations of clonality, coloniality, and mode of germline development in animals
Authors: Blackstone Neil W. , Jasker Bryan D. 
Published: May 2003

AbstractThe hypothesis that individuality is a derived trait in animals (Buss, '87, The Evolution of Individuality, Princeton, NJ: Princeton University Press; Michod, '99, Darwinian Dynamics, Princeton, NJ: Princeton University Press) can be further tested by a “tree‐based” analysis utilizing a comparative methodology and recent phylogenies. We conducted a maximum parsimony analysis in which we mapped character states for clonality, coloniality, and mode of germline development onto four recent phylogenetic hypotheses (Peterson and Eernisse, 2001, Evol Dev 3:170–205). Clonality appears to be a shared primitive character for metazoans. Coloniality, on the other hand, is a derived trait found in relatively few phyla. The germline appears to have been derived at or near the origin of the first bilaterians. The stem‐lineage metazoan thus appears to have been a clonal, acolonial organism that exhibited somatic embryogenesis. The stem‐lineage bilaterian also was likely clonal and acolonial. Nevertheless, this lineage likely exhibited preformation, i.e., its germline was determined during embryonic development. In addition to supporting the hypothesis that the germline is a derived feature in animals, this analysis is relevant to current debates concerning the nature of the latest common ancestor of the bilaterians. J. Exp. Zool. (Mol. Dev. Evol.) 297B: 35–47, 2003. © 2003 Wiley‐Liss, Inc.
Origin of archosaurian integumentary appendages: The bristles of the wild turkey beard express feather‐type β keratins
Authors: Sawyer Roger H. , Washington Lynette D. , Salvatore Brian A. , Glenn Travis C. , Knapp Loren W. 
Published: May 2003

AbstractThe discovery that structurally unique “filamentous integumentary appendages” are associated with several different non‐avian dinosaurs continues to stimulate the development of models to explain the evolutionary origin of feathers. Taking the phylogenetic relationships of the non‐avian dinosaurs into consideration, some models propose that the “filamentous integumentary appendages” represent intermediate stages in the sequential evolution of feathers. Here we present observations on a unique integumentary structure, the bristle of the wild turkey beard, and suggest that this non‐feather appendage provides another explanation for some of the “filamentous integumentary appendages.” Unlike feathers, beard bristles grow continuously from finger‐like outgrows of the integument lacking follicles. We find that these beard bristles, which show simple branching, are hollow, distally, and express the feather‐type β keratins. The significance of these observations to explanations for the evolution of archosaurian integumentary appendages is discussed. J. Exp. Zool. (Mol. Dev. Evol.) 297B: 27–34, 2003. © 2003 Wiley‐Liss, Inc.
Structure and evolution of the Teleost extraretinal rod‐like opsin (errlo) and ocular rod opsin (rho) genes: Is teleost rho a retrogene?
Authors: Bellingham James , Tarttelin Emma E. , Foster Russell G. , Wells Dominic J. 
Published: May 2003

AbstractIn Teleost fish examined to date the ocular rod opsin gene, rho, is intronless, unlike the rod opsin genes of other vertebrate classes which possess a five exon/four intron structure. We have examined in silico the structure of rho (which is expressed uniquely in the retina) and the closely related extraretinal rod‐like opsin (exo‐rhodopsin) gene, errlo (which is expressed uniquely in the pineal), in the puffer‐fish, Fugu rubripes (Takifugu rubripes). Whilst the ocular rho is intronless in common with other Teleosts, the pineal errlo has the five exon/four intron structure common to the rod opsin gene of other vertebrates. A comparison of the sequence surrounding the errlo and rho loci indicates that the errlo locus is syntenic with RHO, the human rod opsin gene, rather than rho. We suggest that the intronless rho may have arisen through an ancient retrotransposition of a mature mRNA originating from errlo. This duplication event has occurred early in the evolution of the Actinopterygii (ray‐finned fish) since the rho of the primitive Actinopterygians such as sturgeon, bowfin, and gar is also intronless. Since it appears that the intron containing errlo is the ancestral opsin gene that gave rise to the intronless rho in the Teleostei, errlo is therefore the true orthologue of the rod opsin gene in other vertebrate classes. We suggest that loss of expression of errlo in the retina could be related to the metabolic and physiological advantages, such as a reduction in splicing events during RNA processing, that may be conferred through possession of an additional, intronless rod opsin gene in the form of rho. J. Exp. Zool. (Mol. Dev. Evol.) 297B: 1–10, 2003. © 2003 Wiley‐Liss, Inc.
Developmental basis of evolutionary digit loss in the Australian lizard Hemiergis
Authors: Shapiro Michael D. , Hanken James , Rosenthal Nadia 
Published: May 2003

AbstractLoss of limb skeletal elements is a recurring theme in tetrapod evolution, but the developmental mechanisms underlying this phenomenon remain largely unknown. The Australian lizard genus Hemiergis offers an excellent model system to study limb reduction among closely related, naturally occurring populations with different numbers of digits. Evolutionary digit loss in Hemiergis does not result from simple truncation of a pentadactyl skeletal developmental program. Rather, the duration of embryonic expression of the patterning molecule Sonic hedgehog (SHH) is shortened in limbs with reduced numbers of digits, and is correlated with decreased cell proliferation in the posterior aspect of the limb. Moreover, this comparative analysis suggests an early role for SHH in specification of digit identity and later importance in maintaining cell proliferation and survival. Subtle changes in spatial or temporal regulation of SHH may alter proliferation and patterning of the developing limb, thereby effecting divergence in adult limb morphology among closely related species. In contrast, expression of MSX and Distal‐less proteins were similar among embryos from different populations. J. Exp. Zool. (Mol. Dev. Evol.) 297B:48–56, 2003. © 2003 Wiley‐Liss, Inc.
Neural expression of the Huntington's disease gene as a chordate evolutionary novelty
Authors: Kauffman Jeffrey S. , Zinovyeva Anna , Yagi Kasumi , Makabe Kazuhiro W. , Raff Rudolf A. 
Published: May 2003

AbstractHuntington's disease is a progressive neuro‐degenerative disorder in humans, which is scharacterized by onset of dementia, muscular ataxia, and death. Huntington's disease is caused by the expansion of the polyglutamine (polyQ) tract in the N‐terminus of the HD protein (Huntingtin). CAG expansion is a dominant gain of function mutation that affects striated neurons in the brain (Cattaneo, 2003, News Physiol Sci 18:34). The evolutionary origins of the vertebrate Hd gene are not well understood. In order to address the evolutionary history of the Hd gene, we have cloned and characterized the expression of the Hd gene in two invertebrate deuterostomes, an echinoderm and an ascidian, and have examined the expression patterns in a phylogenetic context. Echinoderms are basal deuterostomes and ascidians are basal chordates; both are useful for understanding the origins of and evolutionary trends in genes important in vertebrates such as the Huntigton's disease gene. Expression of Hd RNA is detected at all stages of development in both the echinoderm and ascidian studied. In the echinoderm Heliocidaris erythrogramma, Hd is expressed in coelomic mesodermal tissue derivatives, but not in the central nervous system. In the ascidian Halocynthia roretzi expression is located in both mesoderm and nervous tissue. We suggest that the primitive deuterostome expression pattern is not neural. Thus, neural expression of the Hd gene in deuterostomes may be a novel feature of the chordate lineage, and the original role(s) of HD in deuterostomes may have been non‐neural. J. Exp. Zool. (Mol. Dev. Evol.) 297B:57–64, 2003. © 2003 Wiley‐Liss, Inc.
Production of volatile compounds by hairy root cultures of Cichorium intybus L under the influence of fungal elicitors and their analysis using solid‐phase micro extraction gas chromatography–mass spectrometry
Authors: Bais Harsh Pal , Dattatreya BS , Ravishankar GA 
Published: May 2003

AbstractHairy root cultures of Cichorium intybus L produced volatile aromatic compounds under the influence of fungal elicitors. It was observed that the intensity of the production of volatile aromatic compounds in the hairy root cultures of C intybus with 10 ml l−1 media filtrate (MF) of Phytopthora parasitica var nicotiana reached a maximum on the 21st day, as seen by a quantitative flavour profiling method. It was noted that, during the time course, treatment with 10 ml l−1 MF of P parasitica to the MS basal liquid medium containing hairy root cultures of chicory resulted in changed root morphology with cell wall thickening and shear. The components of the volatile aromatic compounds were identified as a propyl isovalerate, undecanal, nonanol, isoamyl nonanoate and 2‐decene‐1‐ol. The mass spectra of all these compounds matched well with the NIST/EPA/NIH library and by comparing with the Kovats index of volatile compounds. The major fruity note was due to the presence of two of the major volatile components, namely propyl isovalerate and isoamyl nonanoate, which were also produced at higher concentration on day 21. This response of chicory hairy root cultures to the fungal elicitor producing volatile aromatic compounds would imply eco‐physiological functions, possibly for plant defence system. Copyright © 2003 Society of Chemical Industry
Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria
Authors: Koleva Irina I , Linssen Jozef PH , van Beek Teris A , Evstatieva Lyuba N , Kortenska Vessela , Handjieva Nedyalka 
Published: May 2003

AbstractPlant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the β‐carotene bleaching test (BCBT), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH•) radical scavenging method and static headspace gas chromatography (HS‐GC) and compared with the antioxidant activity of two reference compounds of different polarity, viz butylated hydroxytoluene (BHT) and rosmarinic acid. The pure reference compounds were applied in a ten‐times lower concentration than the plant extracts. The highest antioxidant activity in the BCBT, close to that of BHT, was observed for the more apolar extracts. The inhibitory effect on β‐carotene bleaching of the polar extracts and rosmarinic acid was much lower than that of BHT. The inhibition of hexanal formation in bulk safflower oil by most of S syriaca and S scardica extracts was as effective as BHT but less so than rosmarinic acid. S montana extracts showed weak antioxidant or even pro‐oxidant properties. Extracts from butanol and from ethyl acetate and the total methanol extracts from all Sideritis plants studied showed a strong radical scavenging activity against DPPH•, close to that of rosmarinic acid. S montana extracts were, as a whole, slightly weaker radical inhibitors than the extracts from the other two species. The antioxidant activity of Sideritis extracts was attributed to the presence of flavonoid and phenylpropanoid glycosides. Copyright © 2003 Society of Chemical Industry