bluuebunny/crossref_metadata_2025_split huggingface dataset:
Explanation for naturally occurring supernumerary limbs in amphibians
Authors: Sessions Stanley K. , Ruth Stephen B. 
Published: June 2005

AbstractThe occasional occurrence of high frequencies of limb abnormalities, including extra limbs, in natural populations of amphibians has long been a puzzle. In this paper we report the discovery of a population in which such limb abnormalities appear to be caused by a parasitic flatworm (trematode) that uses amphibians as intermediate hosts. The cercarial larval stage of the trematode attacks amphibians, penetrating the skin to form cysts (metacercariae). The cysts are preferentially localized in the cloacal region, including the developing hind limb regions in larvae of both frogs (Hyla regilla) and salamanders (Ambystoma macrodactylum). A wide range of limb abnormalities are seen, including duplicated limb structures ranging from extra digits to several extra whole limbs. We hypothesize that these limb abnormalities result from localized regulatory responses of developing and regenerating limb tissues to mechanical disruption caused by the trematode cysts. We have tested this idea by implanting inert resin beads into developing limb buds of frogs and salamanders. Since this treatment can cause supernumerary limb structures, our hypothesis is sufficient to explain the naturally occurring extra limbs.
In vitro effect of osmotic pressure and cortisol on prolactin cell physiology in the coho salmon (Oncorhynchus kisutch) during the parr‐smolt transformation
Authors: Kelley Kevin M. , Nishioka Richard S. , Bern Howard A. 
Published: June 2005

AbstractThe pituitary of the coho salmon (Oncorhynchus kisutch) was studied during the parr‐smolt transformation. Changes in pituitary prolactin (PRL) synthetic rate and influences of osmotic pressure (OP) and cortisol on PRL cell activity were investigated in vitro. After 20‐hr incubations in the presence of 35S‐methionine, tissue and medium were separated and subjected to SDS‐polyacrylamide gel electrophoresis; bands stained with Coomassie Blue R‐250 (= total PRL) and bands on X‐ray film resulting from autoradiography of the gels (= newly synthesized PRL) were quantified by soft laser densitometry. Physiological changes in medium OP exerted no detectable effect on the % release of total or newly synthesized PRL (35S‐PRL), whereas some differences, mostly in the % release of 35S‐PRL, were detected when extraphysiological medium OPs were used. Since OP effects on GH release are similar, these results suggest that OP has no specific direct effect on PRL release under physiological conditions. PRL synthetic rate during the parr‐smolt transformation increased beginning in mid‐February and peaked in mid‐March, but fell to undetectable levels in mid‐April; a second peak in PRL synthesis was observed in mid‐May. These data are in accord with reports on plasma levels of PRL, which further indicate that cortisol levels increase during the April decline in PRL levels. Our in vitro studies demonstrate that cortisol inhibits pituitary PRL synthesis and content in a dose‐related manner and also inhibits the % release of total and 35S‐PRL, suggesting that cortisol may be an important regulator of PRL cell activity during the parr‐smolt transformation.
Trypsin‐like hatching protease from mouse embryos: Evidence for the presence in culture medium and its enzymatic properties
Authors: Sawada Hitoshi , Yamazaki Kimie , Hoshi Motonori 
Published: June 2005

AbstractEnzymatic properties of a protease involved in hatching of mouse embryos were examined. A trypsin‐like protease, which most efficiently hydrolyzed t‐butoxycarbonyl‐Leu‐Ser‐Thr‐Arg‐4‐methylcoumaryl‐7‐amide, was demonstrated in culture medium of mouse hatching embryos. The enzyme was strongly inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, leupeptin, antipain, Nα‐tosyl‐l‐lysyl‐chloromethane, soybean trypsin inhibitor, and Trasylol, but not or weakly inhibited by p‐chloromercuribenzoic acid, EDTA, E‐64, pepstain, chymostatin, and bestatin, suggesting a trypsin‐like serine proteinase. The protease activity in the medium gradually elevated during the course of hatching, whereas the embryo‐associated activity showed no significant change. Furthermore, pyroglutamyl‐Leu‐argininal, the strongest inhibitor for the enzyme among peptidyl argininals, all of which are potent trypsin inhibitors, showed the strongest inhibition toward hatching. Thus, a trypsin‐like protease secreted from hatching embryos into the culture medium may participate in mouse hatching, probably as a hatching enzyme.
Activation of taurine efflux in hypotonically stressed elasmobranch cells: Inhibition by stilbene disulfonates
Authors: Goldstein Leon , Brill Susan R. , Freund Ellen V. 
Published: June 2005

AbstractHypotonic stress activates taurine efflux from elasmobranch cells. The transport mechanism involved in this efflux is not known. In this study we show that the hypotonic‐activated taurine efflux from skate (Raja erinacea) erythrocytes and dogfish (Squalus acanthias) rectal gland tubules is inhibited by stilbene disulfonates. These results suggest that the anion transporter (Band‐3) is involved in the efflux activation mechanism.
Temperature‐adaptive differences between the M4 lactate dehydrogenases of stenothermal and eurythermal sciaenid fishes
Authors: Coppes Zulema L. , Somero George N. 
Published: June 2005

AbstractThe effects of temperature on the apparent Michaelis‐Menten constant (Km) of pyruvate were determined for M4‐lactate dehydrogenases (LDHs) of 15 species of the teleost family Sciaenidae from habitats differing in average temperature and temperature range. The central question addressed was whether adaptive difference in the effect of temperature on an important kinetic parameter, Km, reflect selection based on the range of temperatures experienced by the species, the highest temperature encountered by the species, or both of these factors.For the M4‐LDHs of all 15 species, the Km of pyruvate was conserved between 0.1 and 0.4 mM pyruvate over the species' physiological temperature range. However, large increases in Km of pyruvate commonly were found at temperatures a few degrees C above the species' upper habitat temperature. Distinctions were found between the responses of the enzymes of eurythermal and stenothermal sciaenids. For the most eurythermal species, e.g., Sciaenops ocellatus, Micropogonias undulatus, and Roncador stearnsii, Km of pyruvate varied only about twofold between 10 and 30°C, the temperatures which encompass most of the habitat ranges of these species. For the most stenothermal species, e.g., Cynoscion striatus and Micropogonias furnieri, with habitat temperature ranges of 14–18°C, sharp increases in Km occurred at temperatures above 20°C. We hypothesize that thermal stability of Km values is more strongly selected by maximal habitat temperature than by the amount of variation in habitat temperature, and that adaptation to high temperatures may pre‐adapt enzymes for eurythermal function.
Extraction of vanadium‐binding substance (vanadobin) from a subpopulation of signet ring cells newly identified as vanadocytes in ascidians
Authors: Michibata Hitoshi , Uyama Taro 
Published: June 2005

AbstractWe have previously extracted vanadobin, a substance binding vanadium ions in ascidian blood cells. The present study examined which of several types of blood cell contains this substance, using a combination of cell fractionation, chromatographies, and neutron activation analysis. The vanadium‐containing blood cell type, so‐called vanadocyte, is the signet ring cell in Ascidia sydneiensis samea as well as A. ahodori, and vanadobin was extracted from a homogenate of signet ring cells, but not from morula cells, although the latter have previously been considered to be the vanadocytes.
Ontogenetic changes in proteins and isozyme expression in larval and juvenile bonefish (Albula)
Authors: Pfeiler Edward , Almada Ernestina , Vrijenhoek Robert C. 
Published: June 2005

AbstractDevelopmental changes in soluble proteins and 16 enzymes were followed in metamorphosing leptocephalous larvae and juveniles of the bonefish (Albula sp.) using polyacrylamide gel and starch gel electrophoresis. Metamorphosis was characterized by relatively rapid and pronounced changes in amounts of specific proteins and in expression of different enzymes and isozymes. These effects are assumed to reflect changes in activity of structural genes. The metamorphic change from a largely gelatinous larval body matrix to the juvenile morphology involves a dramatic increase in muscle development. A corresponding increase was observed in the expression of the A4 isozyme of lactate dehydrogenase and the A2 isozyme of creatine kinase, isozymes characteristic of muscle tissue. Increased expression of various isozymes and a specific protein (Mr ∼ 14,000) was also observed in developing eye tissue. Differential expression of isozymes of malate dehydrogenase, lactate dehydrogenase, and glucose‐6‐phosphate isomerase, in early metamorphosing larvae collected from shallow water and deeper water, suggests that the near‐shore environment may be an important factor in “triggering” the metamorphic period.
Development in culture of the chick embryo from fertilized ovum to hatching
Authors: Naito M. , Nirasawa K. , Oishi T. 
Published: June 2005

AbstractAn experiment was carried out to investigate whether thick albumen is essential for the normal development of the chick embryo. Fertilized ova recovered from the oviducts of hens were cultured in vitro and transferred to recipient eggshells with (method A) or without (method B) replacement of the thick albumen by thin albumen. Embryos from freshly laid eggs were transferred to recipient eggshells with (method C) or without (method E) replacement of the thick albumen by thin albumen or with replacement of the thick albumen by thin albumen diluted with solution of salts (method D). Embryos were then incubated until hatching. The rates of hatching of the cultured embryos were 34.4%, 16.2%, 50.0%, 6.9–26.7%, and 47.5% for methods A, B, C, D, and E, respectively. Thus the rate of hatching of cultured fertilized ova was increased by replacement of the thick albumen by thin albumen at the blastoderm stage. Chicks obtained by method A reached maturity and produced viable offspring, and this technique provides an improved method for the culture of fertilized ova to hatching.
Origin of anuran calling: Description of toad releasing
Authors: Schmidt Robert S. , Kemnitz Christopher P. , Hudson Wayne R. 
Published: June 2005

AbstractElectromyographic electrodes were implanted in forelimb muscles of male American toads (Bufo americanus). Toads then were allowed to clasp an artificial clasp object incorporating a pair of solenoids that, when activated, produced a stimulus simulating the side vibrations normally associated with release signalling by conspecific males. Electromyographic activity, in response to the release stimulus, was recorded. The adductor muscle contracted immediately after stimulus onset (causing intensified clasping), responding to the stimulus as a displacement threat. Then the abductor muscle contracted (causing rapid unclasping, or releasing), responding to the stimulus as a release signal. These techniques have provided a better understanding of releasing than has been possible with natural objects (i.e., living males).
Growth rate and plasma corticosterone levels in juvenile alligators maintained at different stocking densities
Authors: Elsey Ruth M. , Joanen Ted , McNease Larry , Lance Valentine 
Published: June 2005

AbstractSixty‐six captive‐reared, juvenile alligators maintained in environmentally controlled chambers were randomly assigned to four treatments consisting of stocking densities of 0.35, 0.18, 0.12, and 0.09 m2/alligator. Alligators were maintained at these densities for 3.5 months. At approximately 4 week intervals the alligators were weighed, measured, and bled via cardiac puncture. Duplicate aliquots of plasma were assayed for corticosterone. All of the alligators continued to grow during the experiment, but alligators maintained at the lowest stocking density were significantly heavier and grew significantly faster (P < 0.01) and had significantly lower plasma corticosterone (P < 0.01) than alligators maintained at the highest stocking density. These results indicate that crowding (i.e., high‐density rearing) of juvenile alligators inhibits maximum growth and that the subsequent stress associated with this crowding results in chronically elevated plasma corticosterone. Plasma corticosterone showed a strong negative correlation with change in body weight; the faster the rate of growth, the lower the hormone levels. These results also show that a single blood sample taken at monthly intervals is sufficient to monitor chronically elevated plasma corticosterone in this species.
Indomethacin inhibits ovarian PGE secretion and gonadotropin‐induced ovulation in a reptile (Anolis carolinensis)
Authors: Jones Richard E. , Orlicky D. J. , Austin Harriet B. , Rand Matthew S. , Lopez Kristin H. 
Published: June 2005

AbstractAlthough prostaglandins (PGs) have been shown to play an important role in gonadotropin‐induced ovulation in mammals, birds, and fishes, nothing is known about the role of PGs in reptilian ovulation. Females of the lizard Anolis carolinensis, each with a large vitellogenic ovarian follicle, were pretreated with an inert subcutaneous pellet or one containing indomethacin (an antiprostaglandin) at a delivery rate of 2.38 μg/lizard/day. Females in each pretreatment group were treated with subcutaneous injections, 7 h apart, of either vehicle alone or 25 μg porcine FSH. They then were sacrificed at 9, 12, and 24 h after the initial injection. After noting whether ovulation had occurred, ovaries from animals with an unovulated large (>5 mm diameter) follicle were incubated in 5 ml Anolis Ringer's for 1 h. The follicles then were examined histologically, and levels of PGE in the incubation medium were determined by radioimmunoassay. FSH significantly induced ovulation in a majority of females by 12 h, and indomethacin significantly reduced the number of FSH‐induced ovulations at 12 h but not at 24 h. Thus, indomethacin delayed FSH‐induced ovulation. Indomethacin also inhibited the preovulatory changes in histology of the follicular wall seen after FSH treatment alone and lowered PGE secretion at all time periods. Secretion of PGE was not influenced by FSH. Thus, prostaglandins may mediate or permit, at the ovarian level, the ovulatory influence of gonadotropin in this reptile.
Adaptive changes of liver composition and structure in golden ide during winter acclimatization
Authors: Segner Helmut , Braunbeck Thomas 
Published: June 2005

AbstractThe present investigation was designed to study hepatic alterations in fish during the winter period and to compare them with acclimation phenomena in fish subjected to fluctuating environmental variables in the laboratory. Immature young‐of‐the‐year golden ide,Leuciscus idus melanotus, were kept in an outdoor pond from September to April. Liver response was analyzed using histological, morphometrical, and biochemical methods.In a first phase from September to March, hepatocellular activity was reduced without evidence of disturbance of liver functions. Cell size, energy reserves, and protein contents as well as mitochondrial number and volume decreased significantly; RNA contents were moderately reduced. Cellular compartmentation was preserved, and gross pathological alterations were lacking. The reduced metabolic capacity of the hepatocyte was apparently compensated for by an increase of total liver mass, resulting in maximum values of all parameters investigated in March.The second phase from March to April was characterized by a decrease of all liver parameters investigated and severe alterations in hepatocellular structure. These observations are interpreted as evidence of drastic structural and functional reorganization in spring.Comparison with data from laboratory fish reveals that part of the wintering phenomena can be attributed to processes of temperature and nutritional adaptation. However, the overall adaptive response observed in golden ide in the outdoor pond profoundly differed from that of fish subjected to selected environmental variables in the laboratory.Since golden ide is in use as a test fish for the assessment of chemical toxicity, the observation of naturally occurring changes in the condition of golden ide may be of relevance with regard to the reproducibility of test results throughout the year.
Vitellin synthesis in relation to oogenesis in in vitro‐incubated ovaries of Penaeus semisulcatus (crustacea, decapoda, penaeidae)
Authors: Browdy C. L. , Fainzilber M. , Tom M. , Loya Y. , Lubzens E. 
Published: June 2005

AbstractOvaries of the penaeid shrimp Penaeus semisulcatus in various stages of oocyte development were incubated in vitro with 14C or 3H leucine. Protein synthesis was measured by TCA precipitation and vitellin specific synthesis by radioimmunoprecipitation. The proteins synthesized were subjected to native or SDS denaturative gel electrophoresis and visualized by fluorography. The results led to the following conclusions: 1) Protein synthesis was found to depend on the concentration of leucine in the culture media. 2) A relatively constant level of vitellin synthesis was observed in ovaries with oocytes ranging in size between 100 and 380 μm. 3) The vitellogenic stage was found to occur in ovaries with oocytes ranging between 100 and 300 μm in size. During this period, 40–60% of the in vitro–synthesized proteins were found to be immunologically identical to vitellin. 4) A decrease in the relative amount of vitellin synthesized was found with the appearance of cortical crypts in oocytes exceeding 300 μm in diameter. 5) The protein immunologically identical to vitellin, which was synthesized in vitro by the ovaries, was found to consist of the subunits found in purified native vitellin. 6) A bioassay system for testing the effect of various factors on vitellin synthesis is suggested by in vitro incubations of several pieces removed from the ovaries of one female.
Aerobic metabolism is maintained in animal tissue during rapid sulfide oxidation in the symbiont‐containing clam Solemya reidi
Authors: Anderson A. E. , Felbeck H. , Childress J. J. 
Published: June 2005

AbstractSolemya reidi is a gutless clam that contains intracellular, symbiotic sulfur‐oxidizing chemoautotrophic bacteria in its gills. It lives in burrows in highly reducing muds rich in sulfide, a compound toxic at low levels to aerobic respiration. In these habitats there is wide variation in levels of O2 and sulfide, both of which are metabolic requirements for this symbiosis. In order to assess whether the animal tissues utilize aerobic or anaerobic ATP‐generating pathways in the presence of sulfide, and to determine the sulfide concentrations that might induce a shift to anaerobiosis, clams were incubated in varying levels of sulfide and oxygen. Symbiont‐free foot tissues from clams incubated in various levels of sulfide (50–500 μM) were analyzed for a common substrate (aspartate) and product (succinate) of invertebrate anaerobic metabolism. The concentrations of these metabolites were compared with those found in tissues of aerobic and anaerobic controls. Aerobic metabolism was maintained in animal tissues in the presence of up to 100 μM sulfide, levels at which maximum autotrophy has been previously reported; however, at higher concentrations, where inhibition of autotrophy has been reported, the onset of anaerobic pathways was evident. This use of anaerobic pathways was not due to the absence of O2, the classical definition of anaerobiosis, but rather to the inhibitory effect of sulfide on aerobic metabolism. The metabolic flexibility of this species in regard to energy metabolism is clearly advantageous living as it does at the interface between a highly oxic environment and an anoxic, highly reducing one.
Comparative kinematics of terrestrial prey capture in Salamanders and newts (Amphibia:Urodela:Salamandridae)
Authors: Miller Brian T. , Larsen John H. 
Published: June 2005

AbstractHigh‐speed cinematography was used to compare the kinematics of terrestrial prey capture among postmetamorphic individuals of the family Salamandridae that have a) terrestrial (Salamandra, Salamandrina, and Tylototriton), b) amphibious (Pleurodeles, Cynops, and Paramesotriton), and c) aquatic (Pachytriton) lifestyles. Tongue projection was common during prey capture attempts in Salamandra, Salamandrina, and Tylototriton, occurred frequently in Cynops and Paramesotriton, but was absent during terrestrial feeding by Pachytriton. The gape cycle consisted of four distinct phases that were associated with discrete movements of the hyolingual apparatus. In all salamandrids that projected the tongue, the gape 1) increased rapidly while the tongue was elevated from the floor of the mouth in preparation for protraction, 2) was stabilized while the tongue was protracted, 3) increased to maximum during retraction and 4) decreased rapidly while the tongue transported the prey into the oral cavity. The absence of tongue projection during some (Cynops, Paramesotriton), or all prey capture attempts (Pachytriton) resulted in gape profiles distinctly different from those described above. Most notably, these profiles lacked the gape stabilization component characteristic of tongue projection. The maximum distance that the tongue was projected beyond the mandible approached 6% snout‐vent length (SVL) in most salamandrids, but reached 20% SVL in Salamandrina. Several elements of the feeding system in Salamandrina are functionally related to the evolution of its specialized tongue projection apparatus. These include a gape cycle of relatively long duration (200 ms) and the absence of a head‐body surge and of eye retraction during the strike.
Differences in the responses of two mudskippers, Boleophthalmus boddaerti and Periophthalmus chrysospilos to changes in salinity
Authors: Chew S. F. , Ip Y. K. 
Published: June 2005

AbstractWhen mudskippers were fully submerged in 100% seawater (SW), the mortality of Boleophthalmus boddaerti was higher than that of Periophthalmus chrysospilos. However, this trend was reversed when mudskippers were submerged in dechlorinated tap water or in 10% SW. The plasma osmolality of P. chrysospilos exposed to 80% SW was significantly higher than that of control fish free to be in or out of 50% SW and that of fish submerged in 10% or 50% SW. The muscle and liver of the fish exposed to 80% SW also contained significantly higher levels of ninhydrin‐positive substances (NPS). In addition, the aminating activity of glutamate dehydrogenase (GDH) in the extracts from the liver and muscle of P. chrysospilos submerged in 80% SW for 7 days was significantly higher than those of fish submerged in 10% SW for the same period. However, the levels of NPS in the muscle and liver of B. boddaerti were unchanged by changes in salinity. Furthermore, the aminating and deaminating activities of GDH in the extracts from the liver and muscle of B. boddaerti, after fish had been submerged in 80% SW for 7 days, were not significantly different from those of fish submerged in 10% SW for a similar period of time. Such differences between the two species of mudskippers in response to changes in salinity may be correlated to the differences in the environmental conditions in their natural habitats.