bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vitellogenin in the camel cricket Ceuthophilus sp. (orthoptera, gryllacrididae)
Authors: Bradley James T. , Kerle Karen Koon , Wolfe Karen G. 
Published: June 2005

AbstractHemolymph and egg yolk proteins in the camel cricket, Ceuthophilus sp., were analyzed by native and SDS‐polyacrylamide gel electrophoresis. Four sex‐specific polypeptides (FSYPs I–IV) accounted for 44% of the hemolymph protein in adult females. These polypeptides were absent from the blood of adult males and female nymphs but composed 63% of the yolk protein in fully grown oocytes. Hemolymph FSYPs became labeled with [35S]‐methionine after a 1‐hour period of in vivo incorporation and appeared in terminal, vitellogenic follicles after 2 hours of incorporation. Two‐dimensional gel electrophoresis showed that all four FSYPs occur in a single egg‐yolk glycoprotein also present in adult female hemolymph. We conclude that this glycoprotein is a multisubunit vitellogenin (VG). Two high molecular weight polypeptides synthesized by the fat body of adult females and immunoreactive with VG‐specific antiserum were tentatively identified as proVGs.
Renal and hormonal responses to atrial natriuretic peptide and turtle atrial extract in the freshwater turtle, Amyda japonica
Authors: Cho Kyung Woo , Kim Suhn Hee , Koh Gou Young , Seul Kyung Hwan 
Published: June 2005

AbstractThe effects of synthetic atrial natriuretic peptide and turtle atrial extract on cardiovascular and renal functions were examined in the freshwater turtle, Amyda japonica.Both the atrium and ventricle of the turtle heart contained an immunoreactive atrial natriuretic peptide. Synthetic rat atrial natriuretic peptide (atriopeptin III) and turtle atrial extract caused a dose‐dependent decrease in mean arterial blood pressure. In turtles that received either atriopeptin III or turtle atrial extract, no significant changes in renal function were observed. However, furosemide was effective in altering renal function. Levels of aldosterone in plasma decreased after 2 hours and increased after 24 hours following injection of atriopeptin III, although the plasma renin concentration did not change.We suggest that the heart of the freshwater turtle may contain an immunoreactive atrial natriuretic peptide and that the atrial natriuretic peptide is more important in the regulation of blood pressure than in the regulation of renal function.
Quantitative studies on variation in sperm head morphology of the hopping mouse, Notomys alexis
Authors: Suttle J. M. , Moore H. D. M. , Peirce E. J. , Breed W. G. 
Published: June 2005

AbstractSpermatozoa from the Australian conilurine rodent, Notomys alexis, display a remarkable degree of variability in head morphology. This variation was quantified by differential counting (n=18 animals) and image analysis (n=4 animals) of spermatozoa recovered from the cauda epididymidis and vasa deferentia. Variability in sperm morphology was exhibited in all individuals examined regardless of age. Sperm heads examined by phase contrast microscopy could be classified into four main types, and in addition, often bizarre forms occurred that ranged in shape from having a small dorsocaudal projection to being ovoid or dome‐shaped. Measured by image analysis, sperm nuclear size for Notomys alexis ranged from 2.21 to 6.94 μm2 (mean 4.34 ± 0.94 μm2) as compared with a range of 4.53–5.82 μm2 (mean 5.33 ± 0.26 μm2) for spermatozoa from Pseudomys australis, a closely related species. The acrosome of Notomys alexis spermatozoa also exhibited considerable morphological variation as detected by immunolocalisation with a monoclonal antibody to a mammalian acrosomal antigen.This variability exhibited by both the acrosome and the nucleus of the sperm head in Notomys alexis may relate to low levels of intermale sperm competition that probably occurs in these animals.
Changes in pituitary responsiveness during the ovulatory cycle of the Japanese quail, in vitro
Authors: Connolly Peter B. , Callard Ian P. 
Published: June 2005

AbstractAnterior pituitary glands from ovulating Japanese quail (Coturnix coturnix) were used to investigate variation in sensitivity to chicken luteinizing hormone‐releasing hormone (cLHRH I; Gln8‐LHRH). Grouping the pituitaries by ovulatory stage provided preliminary evidence of changes in sensitivity to LHRH during the ovulatory cycle. Pituitaries taken from quail before the preovulatory LH surge were responsive to cLHRH I, while pituitaries from the other times of the cycle showed minimal response to cLHRH I. Female pituitary glands release less LH than those of males. These data indicate a change in sensitivity to LHRH in the female quail that may be due to changes in gonadal steroids or the pool of releaseable LH from the pituitary.
Protein‐free culture medium containing polyvinylalcohol, vitamins, and amino acids supports development of eight‐cell hamster embryos to hatching blastocysts
Authors: Kane Michael T. , Bavister Barry D. 
Published: June 2005

AbstractIn vitro development of eight‐cell hamster embryos to hatching blastocysts requires the presence of amino acids and a group of water‐soluble vitamins in the culture medium. The present studies investigated the effect of type of macromolecule on blastocyst hatching and on the requirement for vitamins. Embryos were cultured for 3 days in the presence of the synthetic macromolecule polyvinylalcohol (PVA) and of different types of bovine serum albumin (BSA), both with and without vitamins. The results showed that eight‐cell embryos develop to hatching blastocysts in the presence of vitamins and amino acids with PVA as the only macromolecule in the medium. The presence of certain types of BSA reduced but did not eliminate the need for vitamins. Glutamine alone was as efficient as a complete amino acid supplement in supporting blastocyst hatching. These results demonstrate for the first time that eight‐cell hamster embryos can be cultured to hatching blastocysts in a chemically defined medium.
Coronary drainage in the Octopus vulgaris systemic heart
Authors: Agnisola C. , Zummo G. , Tota B. 
Published: June 2005

AbstractThe vascular architecture of the coronary system of the systemic heart of the octopus (Octopus vulgaris) has been studied by means of both the corrosion‐cast method and scanning electron microscopy. It is shown that the Octopus systemic heart myocardium is supplied through a very rich capillary network, the complexity of which probably reflects the complex organization of the ventricular wall. Drainage occurs by way of a classic venous system that originates from this capillary network. Morphological evidences are reported indicating that the coronary bed communicates directly with the ventricular lumen. In the isolated perfused systemic heart, the flow through this system is related directly to cardiac contractility. In an in situ preparation of the systemic heart, where for the first time simultaneous records have been obtained, ventricular pressure, coronary vein pressure, and coronary flow appear to be time related. It is suggested that in Octopus the venous coronary flow is not dependent on the systemic arterial pressure, as in the vertebrate heart, but it is directly dependent on intraventricular pressure.
Unexpected divergence among identified interneurons in different abdominal segments of the crayfish Procambarus clarkii
Authors: Larimer James L. , Pease Craig M. 
Published: June 2005

AbstractThe command elements that initiate and coordinate the abdominal movements in crayfish show little similarity between the various abdominal segments. Our criteria for similarity among interneurons were based on both cell morphology and electrophysiology. By contrast, previously published evidence shows much greater intersegmental similarity in the skeletal, muscular, motoneuronal, and sensory components of the abdominal system in crayfish, structures that are controlled by or send information to the command elements. Therefore, unlike the command elements, these structures have retained nearly identical form and function in the various segments.We also found in different ganglia examples of interneurons involved with abdominal positioning behavior that have similar morphology but different function and vice versa. Such interneurons could represent divergent pairs of serial homologues. It is unknown why so many of the abdominal positioning interneurons have become different. The various ganglia may perform subtly different functions, requiring differences in the positioning interneurons but not in the motor neurons or muscles. Alternatively, some of the abdominal positioning interneurons underlie more than one behavior; consequently, selection acting on these multiple functions may have changed these interneurons through evolution.
Feminization of the hepatic microsomal cytochrome P‐450 system in brook trout by estradiol, testosterone, and pituitary factors
Authors: Pajor Ana M. , Stegeman John J. , Thomas Peter , Woodin Bruce R. 
Published: June 2005

AbstractThe effects of estradiol, testosterone, and pituitary extract on hepatic microsomal enzymes were studied in sham‐operated and gonadectomized immature brook trout. Estradiol reduced the specific content of cytochromes P‐450 and b5 by 70% or more in both groups. Testosterone and pituitary extract also decreased the levels of total P‐450 and b5, but to a lesser extent. These latter effects were not evident when the contents of P‐450 and b5 were normalized per g liver. Immunoblot analysis with antibodies to P‐450 forms from a teleost (scup) showed the presence of cross‐reacting proteins in control fish, presumed counterparts to the scup forms. Levels of a trout counterpart to P‐450A (a putative testosterone 6β‐hydroxylase) were strongly suppressed in estradiol‐treated fish. A trout P‐450B counterpart was suppressed in estradiol‐treated fish, but less strongly than was the P‐450A counterpart. The trout orthologue of hydrocarbon‐inducible P‐450E (P‐450IA1), the aryl hydrocarbon hydroxylase (AHH) catalyst, was undetectable in any group, consistent with very low levels of AHH activity in these fish. Estradiol or pituitary extract also decreased the levels of NADH‐cytochrome b5 and NADPH‐cytochrome P‐450 reductase activities in sham‐operated but not in gonadectomized fish. Gonadectomy alone also lowered the levels of reductase activities but not of total P‐450 or b5, suggesting an influence of gonads in maintaining normal levels of the reductases. The results support a prominent suppressive role for estrogens in producing the general sex differences in microsomal enzymes in fish liver and indicate that there could be affects on several P‐450 forms. However, the mechanism of hormone action in this regulation is uncertain. The results also suggest the existence of unidentified, possibly gonadal, factors which contribute to the regulation of reductases in teleost liver.
Developmental change in follicular cell‐enhanced amino acid uptake into mouse oocytes that depends on intact gap junctions and transport system gly
Authors: Haghighat Nasrin , Van Winkle Lon J. 
Published: June 2005

AbstractUptake of L‐alanine, L‐lysine, and choline into both preantral and antral mouse oocytes was enhanced by follicular cells. Follicular cells also enhanced glycine uptake into oocytes at the preantral stage of development, but no effect of these cells was observed at the antral stage. Glycine uptake was predominantly Na+ dependent and inhibited almost completely by 10 mM sarcosine, moderately by proline and its analog pipecolate, and poorly or not at all by other amino acids. By these criteria, glycine transport was mainly via system Gly in follicular cells and the oolemma at both the preantral and antral stages. Moreover, an increase in glycine transport via the oolemma between the preantral and antral stages was more than threefold larger than was the increase in transport of alanine or lysine. This relatively large increase in glycine‐specific transport in the oolemma appears to obscure the ability of follicular cells to enhance glycine uptake into antral oocytes. In contrast to other amino acids, leucine uptake into oocytes was not enhanced by follicular cells unless 14 other amino acids were also present at their concentrations in mouse serum. An inhibitor of gap junctional communication, 18‐α‐glycyrrhetinic acid, abolished follicular cell‐enhanced uptake of glycine and choline into preantral oocytes. Therefore, the extent to which follicular cells enhance uptake of a particular amino acid into oocytes depends on at least three physiologically important variables. Namely, enhancement may depend on the stage of follicular development, the presence of other amino acids in the environment, and gap junctional communication.
Lactate production in the gills of the mudskipper Periophthalmodon schlosseri exposed to hypoxia
Authors: Ip Y. K. , Low W. P. 
Published: June 2005

AbstractFish gills are generally regarded as lactate‐consuming organs. However, the mudskipper, Periophthalmodon schlosseri, which is euryhaline, amphibious, and frequently exposed to environmental hypoxia in its natural habitat, accumulated significantly greater (P < 0.01) amount of lactate in its gills under experimental hypoxic condition (4.82 ± 1.22 μmol/g) than those of the control normoxic fish (2.43 ± 0.22 μmol/g). Perfused gills incubated in vitro under hypoxia for 1 hr also contained a greater amount of lactate (8.77 ± 0.25 μmol/g) than those incubated in normoxic condition (2.39 ± 0.75 μmol/g). These results proved that the branchial tissues of P. schlosseri can produce lactate under hypoxia from some endogenous substrates, which have yet to be determined. Lactate dehydrogenase extracted from the gills of the mudskipper also showed high ratio of pyruvate‐reducing activity to lactate‐oxidizing activity, indicating that its brachial tissues have a greater capacity for lactate production than those of other fishes.
Tissue‐specific regulation of pyruvate kinase during environmental anoxia in Concholepas concholepas (Gastropoda: Muricidae)
Authors: Carvajal Nelson , González Ruby , Kessi Eduardo 
Published: June 2005

AbstractThe effects of anoxia on pyruvate kinases (PK) from the heart and foot muscle of Concholepas concholepas, as well as the presence and levels of phosphoenolpyruvate carboxykinase (PEPCK) in the aerobic and anoxic tissues, were examined. In response to anoxia, the maximal activity of pyruvate kinase decreased in the heart but was not altered in the foot muscle. Phosphoenolpyruvate carboxykinase was not detected in the foot muscle and anoxic stress had no effect on the activity of this enzyme in the heart tissue. Anoxic stress altered the kinetic and regulatory properties of heart PK without any change in the foot muscle enzyme. Anoxic heart PK was much more dependent of fructose 1,6‐diphosphate for significant activity at low concentrations of phos‐phoenolpyruvate and had a higher sensitivity to inhibition by alanine and ATP than the aerobic enzyme from. All changes were reversed when the animals were transferred to well‐aerated seawater. The results are compatible with the operation of a succinate pathway of glycogen degradation during prolonged environmental anoxia in the heart, but not in the foot muscle tissue of C. concholepas.
Effects of temperature acclimation on muscle relaxation in the carp: A mechanical, biochemical, and ultrastructural study
Authors: Fleming J. R. , Crockford T. , Altringham J. D. , Johnston I. A. 
Published: June 2005

AbstractCommon carp (Cyprinus carpio L.) were acclimated to either 5–8°C or 20–25°C for a minimum of 1 month, and the twitch contraction kinetics of a myotomal nerve‐muscle preparation were investigated. A significant compensation for the acute effects of temperature was achieved in twitch kinetics by acclimation to 8°C. An acute drop in temperature from 20 to 8°C in preparations from warm‐acclimated fish led to approximately two‐ to three‐fold increases in the half‐times for activation and relaxation. At 8°C, values were 50% faster in 8°C‐ than in 20°C‐acclimated fish, indicating a partial capacity adaptation in rates of both twitch activation and relaxation.The mechanisms underlying temperature compensation of twitch contraction kinetics were investigated. A quantitative ultrastructural study was performed on the sarcoplasmic reticulum (S.R.) of fast and slow myotomal muscles. No differences were found in the surface and volume densities of the S.R. in fast‐twitch fibres between cold‐ and warm‐acclimated fish. The surface densities of terminal cisternae and S.R. were higher in slow‐twitch fibres from the warm‐acclimated fish. Parvalbumin concentration in fast fibres was found to be independent of acclimation temperature (0.61–0.68 mmol/kg wet weight). Although the relative proportions of parvalbumin isoforms (I–IV) showed considerable individual variation this was not correlated with environmental temperature. The Ca2+‐ATPase activity of S.R.‐enriched microsomes prepared from fast myotomal muscle was 60% higher at 8°C in cold‐ than warm‐acclimated carp. This suggests that changes in the kinetics and/or density of Ca2+ pumps contribute to the observed capacity adaptation in relaxation rate with temperature acclimation. Other possible mechanisms underlying the plasticity of twitch contraction kinetics in carp are briefly discussed.
Oxygen reduction metabolism by the digestive gland of the common marine mussel, Mytilus edulis L.
Authors: Winston Gary W. , Livingstone David R. , Lips Franz 
Published: June 2005

AbstractPartial reduction of molecular oxygen (O2) produces reactive oxygen species such as the superoxide anion radical (O−2) and H2O2. Redox cycling of iron promotes the conversion of O−2 and H2O2 to the highly reactive and potentially destructive hydroxyl radical (·OH). These processes of one‐electron metabolism of O2 were studied in digestive gland microsomes of the marine mussel, M. edulis L. by using the free radical scavengers benzoate and 2‐keto‐4‐methiolbutyric acid (KMBA) to detect ·OH. Benzoate was decarboxylated and 2‐keto‐4‐methiolbutyric acid (KMBA) was oxidized to ethylene by M. edulis microsomal electron transport (MET) in a reaction that was stimulated by ferric‐EDTA and sodium azide (an inhibitor of catalase), suggesting that H2O2 was the precursor of the oxidizing species. In contrast to previous reports on rat liver microsomes (Jewell and Winston, '89), NADH supported a two to three times higher rate of oxyradical production than did NADPH. After a 10 min lag phase, NADH‐dependent KMBA oxidation was linear up to at least 60 min. NADPH‐dependent KMBA oxidation showed no lag phase and was linear for 30–40 min. In the presence of ferric‐EDTA, NADH‐dependent KMBA oxidation was weakly inhibited by superoxide dismutase (approximately 15%) whereas NADPH‐dependent KMBA oxidation was inhibited nearly 40%. As ferrous iron is required for ·OH from H2O2, ferric iron is at least in part reduced directly by MET and to a greater extent with NADH as electron donor than with NADPH. These data show that M. edulis microsomes generate superoxide/H2O2 during MET and in the presence of ferric‐EDTA can oxidize ·OH scavengers, albeit via different mechanisms.Cytosol accounted foremost of the oxyradical‐generating capacity of digestive gland post 9,000g supernatant. A substantial nonpyridine nucleotide‐dependent oxyradical‐generating activity was found in cytosol that was removed by G‐25 Sephadex filtration. Protective antioxidant enzymes were present in digestive gland, indicating an in vivo scenario for oxyradical production.
Fate mapping the avian epiblast with focal injections of a fluorescent‐histochemical marker: Ectodermal derivatives
Authors: Schoenwolf Gary C. , Sheard Philip 
Published: June 2005

AbstractA microinjection technique is described for fate mapping the epiblast of avian embryos. It consists of injecting the epiblast of cultured blastoderms with a fluorescent‐histochemical marker, examining rhodamine fluorescence at the time of injection in living blastoderms, and assaying for horseradish peroxidase activity in histological sections obtained from the same embryos collected 24 h postinjection. Our results demonstrate that this procedure routinely marks cells, allowing their fates to be determined and prospective fate maps to be constructed. Two such maps are presented for ectodermal derivatives of the epiblast: one for late stages of Hensen's node progression (stages 3c through 4) and one for early stages of node regression (stages 4 + through 5). These new maps have six significant features. First, they show that regardless of whether the node is progressing or regressing, the flat neural plate extends at least 300 μm cranial to, 300 μm bilateral to and 1 mm caudal to the center of Hensen's node. Second, they confirm our previous fate mapping studies based on quail/chick chimeras. Namely, they show that the prenodal midline region of the epiblast forms the floor of the forebrain and the ventrolateral part of the optic vesicles as well as MHP cells (i.e., mainly wedge‐shaped neurepithelial cells contained within the median hinge point of the bending neural plate); in contrast, paranodal and postnodal regions contribute L cells (i.e., mainly spindle‐shaped neurepithelial cells constituting the lateral aspects of the neural plate). Third, they reveal a second source of MHP cells, Hensen's node, verifying previous studies of others based on tritiated thymidine labeling. Fourth, they demonstrate, in contrast to studies of others based on vital staining, carbon marking, and choriolallantoic grafting but in accordance with our previous studies based on quail/chick chimeras, that the cells contributing to the four craniocaudal subdivisions of the neural tube (i.e., forebrain, midbrain, hindbrain, and spinal cord) are not yet spatially segregated from one another at the flat neural plate stage, although more cranial neural plate cells tend to form more cranial subdivisions and more caudal cells tend to form more caudal subdivisions. Thus, single injections routinely mark multiple neural tube subdivisions. Probable reasons for the discrepancy between our present results and the previous results of others is discussed. Fifth, they suggest that cells contributing to the surface ectoderm and neural plate are not yet completely spatially segregated from one another at the flat neural plate stage, particularly in caudal postnodal regions. Sixth, they delineate the locations of the otic placodes. Therefore, the microinjection technique has contributed important new information about the avian epiblast and, in particular, about the neural plate and its subdivisions.
Sexual dimorphism in the hindlimb of Eleutherodactylus coqui: Does behavior predict morphology?
Authors: Townsend Daniel S. , Wassersug Richard J. , King V. Ann , Elder Geoffrey C. B. 
Published: June 2005

AbstractEleutherodactylus coqui differs from most other anuran amphibians in that it has internal fertilization. This requires close apposition of male and female cloacae during amplexus, achieved by a reverse hindleg clasp (RHLC) where—rather than the male clasping the female with his forelimbs, as occurs in most anurans—the female adducts her hindlimbs around the male. Since normal amplexus in anurans is associated with enlarged forelimb muscles in males of some species, we asked whether the RHLC of E. coqui was associated with enlarged hindlimb adductors in the female or with other sexually dimorphic myological specializations. Several features, such as muscle fiber number, size, type, and overall cross‐sectional area were compared between male and female adult E. coqui for two muscles essential to the RHLC and a control hindlimb muscle not used in the behavior. No sexual dimorphism was found that could be specifically related to the RHLC. While muscles in all cases were larger in the females than in the males, this was accounted for by the larger body size of females in this species.