bluuebunny/crossref_metadata_2025_split huggingface dataset:
Presence of soluble tetrameric (blood) and membrane‐bound dimeric forms of cholinesterase in the mollusk Murex brandaris (Gastropoda: Neogastropoda)
Authors: Talesa Vincenzo , Grauso Marta , Principato Giovanni B. , Giovannini Elvio , Norton Scott J. , Rosi Gabriella 
Published: June 2005

AbstractIn the marine snail Murex brandaris about 80% of cholinesterase (ChE) activity lies in the blood. It can be recovered as a fully soluble (FS) form by mincing the whole animal. Two more ChE forms, detergent (DS) and high‐salt soluble (HSS) (18 and 2% of total ChE activity, respectively), can then be sequentially extracted from the other tissues. FS and DS ChEs were purified to homogeneity by affinity chromatography on procainamide‐or edrophonium‐Sepharose respectively. The small amount of HSS prevented a similar purification and an extensive characterization. According to density gradient centrifugation, gel‐filtration chromatography, and SDS‐PAGE, FS ChE is likely a globular tetramer of a 66 kDa subunit (10.8 sedimentation constant [S], 270 kDa). Moreover, it is an amphiphilic form including a hydrophobic domain. DS ChE appears to be a globular dimer of a 66 kDa subunit (5.6 S, 137 kDa). The amphiphilicity of this enzyme is likely due to a phosphatidylinositol on the catalytic subunits, also responsible for detergent interaction as well as cell membrane insertion. Both FS and DS forms hydrolyze propionylthiocholine faster than other choline thioester substrates. They also show high catalytic efficiency with other choline esters as substrates, likely due to a wide and relatively unspecialized conformation of the active site. Immunological cross‐reactivity showed wide structural affinity between FS and DS forms. Antibody‐enzyme bond gave partial inactivation. On the whole, the results suggest that both FS and DS forms likely originate from only one gene. Differences in quaternary structure and solubility could reflect posttranslational modifications or alternative splicing. © 1994 Wiley‐Liss, Inc.
Scaling of the locomotory apparatus and paddling rhythm in swimming mallard ducklings (Anas platyrhynchos): Test of a resonance model
Authors: Clark Brian D. , Fish Frank E. 
Published: June 2005

AbstractIt was hypothesized that the constant propulsive frequencies observed in several paddling animals as they swim at different speeds reflects “resonance‐like” swimming mechanics. This behavior may result if the hydrodynamic load on the paddle is dominated by acceleration‐dependent, rather than velocity‐dependent, terms, and the musculoskeletal system operates with nearly constant stiffness over a large fraction of the propulsive cycle. A model was developed that uses the form of the paddle and the architecture of a representative limb muscle (lateral gastrocnemius) to predict a value proportional to propulsive frequency in mallard ducklings of different size. Fifteen ducklings were videotaped as they swam in a water channel, and the measured frequencies were compared to model predictions. Although the predicted and measured frequencies were highly correlated (r = 0.926), the 95% confidence interval estimated for the intercept of the reduced major axis fit to the points did not span the origin. This lack of proportionality means that even though it could account for much of the observed variation in paddling frequencies, the present model of resonance‐like swimming is not supported. © 1994 Wiley‐Liss, Inc.
Regulation of DNA synthesis in goldfish vitellogenic ovarian follicles by hormones and growth factors
Authors: Srivastava Rakesh Kumar , Van Der Kraak Glen 
Published: June 2005

AbstractThe present study examines the effects of selected hormones and growth factors on deoxyribonucleic acid (DNA) synthesis by goldfish vitellogenic and prematurational full‐grown ovarian follicles in vitro. The synthesis of DNA was assessed from the incorporation of [3H]‐thymidine after preincubation in medium supplemented with fetal bovine serum, followed by a second incubation in serum‐free medium with several combinations of hormones and growth factors. DNA synthesis by vitellogenic ovarian follicles was enhanced by the addition of ovine and porcine insulin (0.4–40 μg/ml) and human recombinant insulin‐like growth factor I (IGF‐I, 12.5–100 ng/ml) and IGF‐II (50–100 ng/ml); the order of potency was IGF‐I > IGF‐II > insulin. The interactive effects of insulin, IGF‐I, and IGF‐II on DNA synthesis by vitellogenic follicles were additive, suggesting that these peptides may act through distinct receptors. By comparison, both insulin (4 μg/ml) and IGF‐I (100 ng/ml) had no effect on DNA synthesis by prematurational full‐grown follicles, suggesting that sensitivity of ovarian follicles to insulin and IGF‐I may change during follicular development. IGF‐I (25–200 ng/ml) and IGF‐II (25–200 ng/ml) had no effect on basal and human chorionic gonadotropin (hCG)‐stimulated testosterone and 17β‐estradiol production by vitellogenic follicles, suggesting that these growth factors may play a role in regulating follicular DNA synthesis but not ovarian steroidogenesis. Carp gonadotropins (cGtH‐I and cGtH‐II), hCG, and 17β‐estradiol also enhanced DNA synthesis by vitellogenic follicles. The effects of hCG and 17β‐estradiol on DNA synthesis were further enhanced in the presence of either insulin or IGF‐I. In conclusion, these data provide convincing evidence of the mitogenic actions of insulin, IGFs, gonadotropins, and 17β‐estradiol, suggesting that these hormones and growth factors may regulate follicular growth and development in the goldfish. © 1994 Wiley‐Liss, Inc.
Allorecognition/xenorecognition responses in Botrylloides (ascidiacea) subpopulations from the mediterranean coast of Israel
Authors: Rinkevich Baruch , Lilker‐Levav Tami , Goren Menachem 
Published: June 2005

AbstractExaminations of Botrylloides colonies along the Mediterranean coast of Israel have revealed the existence of three distinct morphs (subpopulations, SPs) which differ in some morphological characteristics and life history patterns. Here we study allorecognition and xenorecognition responses expressed by colonies of three SPs, by employing >400 colony allorecognition and xenorecognition assays. SP1 colonies exhibited a new type of nonself response by the formation of giant ampullae, the megaloampullae. These special structures appeared 1–5 days after first ampullae‐to‐ampullae contacts were established, in assays either within SPs or between SPs, and in xenogeneic challenges with Botryllus schlosseri but not with Didemnum. The megaloampullae developed from regular ampullae, which dilated up to 7 times their normal width and 1.5 times their length, but were usually not involved in cytotoxic reactions. SP2 and SP3 colonies produced “fusion‐rejection” responses in within‐SP assays; however, they may develop hemorrhages only when challenged between SPs (also with SP1 colonies) or xenogenetically with B. schlosseri. No xenogeneic response was recorded when the colonies were assayed with Didemnum. The fusion‐rejection response is characterized by reciprocal penetration of ampullae, develops to short‐term blood vessel anastomosis with increased numbers of amebocytes and macrophages, followed by a limited exchange of blood cells, and subsequently terminates in ampullae amputation and cell death. Hemorrhages developed without ampullae penetration. We studied fusion frequencies in SP1 and SP3 colonies collected from an area of 20 × 30 m. Both combinations of within‐SP assays revealed high rates of fusion (12.5 and 35.0%, revealing 30 and 10 allorecognition alleles on the fusibility locus, respectively), but no fusion was recorded in 50 between‐SP assays. The types of allogeneic responses may indicate that SP2 and SP3 are taxonomically closer to one another than to SP1, a conclusion which is not supported by analyzing morphological, ecological, and developmental features characteristic of the three Botrylloides spp. We also discuss here the phenomenon that some invertebrates express repeatability and specifically more than one distinctive nonself reaction, which indicates the complexity of invertebrate immune responses. © 1994 Wiley‐Liss, Inc.
Origin of the oocyte shell membrane of a dasyurid marsupial: An immunohistochemical study
Authors: Roberts Claire T. , Breed William G. , Mayrhofer Graham 
Published: June 2005

AbstractPolyclonal antibodies were raised against the extracellular coats (mucoid and shell membrane) of unfertilized oocytes and early embryos of a dasyurid marsupial, the fat‐tailed dunnart (Sminthopsis crassicaudata). Indirect immunofluorescence was used to test the specificity of the antibodies to the shell membrane. Streptavidin/biotin immunoperoxidase cytochemistry revealed that precursors of the tertiary egg membranes are secreted by the luminal epithelium of the ampulla, isthmus (including the crypts), utero‐tubal junction, and adjacent endometrial glands. Histochemistry distinguished between the sites of mucoid and shell membrane precursor secretion. The mucoid coat stained positively with Alcian blue at pH 1.0 and 2.5, with Alcian blue at pH 0.2 after performic acid oxidation, and with PAS which was amylase resistant. Some of the luminal epithelial cells of the ampulla and isthmus, as well as its crypts, also stained positively by these histochemical methods but the luminal epithelium of the utero‐tubal junction and endometrial glands were negative for all methods. The shell membrane did not stain with any of the above methods nor with dihydroxy‐dinapthyl‐disulphide (DDD) or ferric ferricyanide but it was eosinophilic and stained positively with the red cytoplasmic stain of Masson's trichrome. Therefore, it is concluded that shell membrane precursors are secreted by the luminal epithelium of the utero‐tubal junction, adjacent glands, and by scattered glands in the anterior region of the uterus but not by any cell population of the oviduct. © 1994 Wiley‐Liss, Inc.
Unusual response of Artemia franciscana embryos to prolonged anoxia
Authors: Clegg James S. 
Published: June 2005

AbstractEncysted embryos of the crustacean Artemia franciscana are shown to survive at least 2 years of continuous anoxia, a record unequaled by any other free‐living animal. This result, in conjunction with previous findings, supports the possibility that these embryos are an exception to the generality that a constant flow of free energy is required for eukaryotic cell survival, under ordinary conditions of temperature and water content. © 1994 Wiley‐Liss, Inc.
The effect of blocking inputs of the acoustic trachea on the frequency tuning of primary auditory receptors in two species of tettigoniids
Authors: Kalmring Klaus , Jatho Martin 
Published: June 2005

AbstractThe effect of plugging the input structures of the acoustic trachea of the forelegs of two tettigoniid species on the frequency tuning of the auditory receptor cells of the intermediate organ and of the crista acoustica was investigated. This was performed by long‐lasting single cell recordings by which the threshold curves of the cells were studied before and after carrying out manipulations on the ipsilateral slits and/or the spiracles. In some cases the distal tibia was also cut off during the experiments. Plugging the ipsilateral slits and/or the spiracle with Vaseline has different effects on the frequency tuning of the auditory receptor cells. Closing the slits has a relatively small damping effect being uniform in the stimulus frequency range between 2 kHz and 40 kHz. The tuning curves are left basically unchanged apart from a low elevation of the threshold by a few dB. Occluding the ipsilateral spiracle leads to a frequency‐dependent damping on the activity of the receptors, becoming stronger with increase of the stimulus frequency. Generally, the threshold curves are a few dB less sensitive at their characteristic frequencies and the tuning curves are shifted to lower frequencies, whereby the low frequency threshold curve sides of the receptors are more sensitive by about +2dB to +10 dB and the high frequency sides of the neurons are less sensitive by −5 dB up to −30 dB, depending on the stimulus frequency. When calculating the threshold difference from the threshold curves before and after blocking the ipsilateral spiracle in Mygalopsis marki, three groups of receptor cells can be determined. All low frequency receptors and some of the middle range receptors have zero values (i.e., no difference before and after plugging the spiracle) of the threshold differences at 5 kHz. Many middle range receptors and some of the ultrasonic receptors possess zero values at 10 kHz, and some of the ultrasonic receptors even have them at 20 kHz. The conditions in Mygalopsis marki are similar to those in Gampsocleis gratiosa (the species investigated), although, in the latter, the whole effect is transformed to lower frequencies that may result from the different sensitivity of the organs at low frequency level. Gampsocleis gratiosa has a higher proportion of low frequency to high frequency receptor cells in the organs than Mygalopsis marki. The effect of plugging the inputs of the acoustic trachea on the tuning of the auditory receptor cells is explained by a simple (acousto‐mechanical) model of frequency‐induced movements at the receptor row inside the organ. © Wiley‐Liss, Inc.
Seasonal changes of the adrenocortical responses to stress in redpolls, Acanthis flammea, in Alaska
Authors: Wingfield John C. , Deviche Pierre , Sharbaugh Susan , Astheimer Lee B. , Holberton Rebecca , Suydam Robert , Hunt Kathleen 
Published: June 2005

AbstractMale and female redpolls (Acanthis flammea) showed marked increases in circulating corticosterone up to 1 hour after exposure to a common stress—capture, handling and restraint—indicating that their hypothalamo‐pituitary‐adrenal axis responded to acute stress in a manner similar to that of other vertebrates. We used this protocol as a measure of responsiveness of the adrenocortical cells to acute stress in general and for comparison with gender and across seasons. In both sexes the adrenocortical response to stress was reduced in January (at Fairbanks, 64°N) and maximal when birds were breeding in June at Toolik Lake (69°N). The elevation of circulating corticosterone following capture and handling in breeding males at Barrow (71°N) was significantly less than in breeding males at Toolik Lake. There were also considerable variations among individuals in the intensity of the adrenocortical responses, particularly in the maximum levels of corticosterone attained. This individual variation correlated significantly with fat score and/or body mass in both sexes only in breeding birds at Barrow. This difference may be explained by generally lower, and thus reduced variability in body fat and mass in birds sampled in the warmer climate of Toolik Lake. A similar trend was seen in non‐breeding birds, but this was not significant. Additionally, in January, baseline cortisterone levels in males were correlated with body mass, although this relationship did not hold when both sexes were considered. Body mass and fat score in winter were similar to those of redpolls sampled at Barrow in June. These data suggest that redpolls may be able to adjust their responsiveness to acute stresses in relation to fat stores. Those with greater fat depots had reduced responsiveness to stress. © Wiley‐Liss, Inc.
Reactivated movement of decondensed rat sperm models and a description of their ultrastructure
Authors: Morcos Yvette , Swan Margaret Anne 
Published: June 2005

AbstractThis study aimed at finding optimal conditions to decondense rat sperm nuclear chromatin with minimal damage. This was judged by the ability of the sperm‐tail axoneme in the partially decondensed sperm models to be reactivated. Decondensation was assessed by phase contrast microscopy. Partial decondensation was judged to occur when the bright refractive appearance of the sperm nucleus turned black, and full decondensation when the nucleus turned pale and increased in volume. Demembranation was shown to have occurred by electron microscopy. With 0.03% Triton X‐100 rat caudal epididymal sperm were partially demembranated to produce sperm models. Demembranation using a 0.1% solution of Triton X‐100 was complete, but as with the solution of 0.05% Triton X‐100, resulted in poorer reactivation of the partially decondensed sperm models. Reactivated movement of decondensed sperm models was used to assess the effect of the decondensing agents DTT and heparin. We were only able to achieve reactivation of sperm models that had undergone partial decondensation. Optimal reactivation was obtained after rat sperm models had decondensed in the decondensation solution containing 5 mM DTT, 6 mM EDTA, and 27.3 or 34.1 USP/ml heparin. Concentrations of heparin above or below these values resulted in a decrease in the number of sperm models reactivated. Ultrastructurally, sperm partially decondensed with 5 mM DTT, 6 mM EDTA, and 34.1 USP/ml heparin had their plasma membrane further extracted compared with sperm treated with 0.03% Triton X‐100 alone. Decondensation was greatest in the peripheral regions of the nucleus with extraction of the acrosome but not of the perforatorium. The decondensed regions had a filamentous appearance. This procedure will allow access to sperm nuclear chromatin for experimental manipulation in rat sperm models. © Wiley‐Liss, Inc.
Hatchling sex in the marine turtle Caretta caretta is determined by proportion of development at a temperature, not daily duration of exposure
Authors: Georges Arthur , Limpus Colin , Stoutjesdijk Ros 
Published: June 2005

AbstractMean daily temperature in natural nests of freshwater turtles with temperature dependent sex determination is a poor predictor of hatchling sex ratios when nest temperatures fluctuate. To account for this, a mathematical model has been developed on the assumption that hatchling sex depends on the daily proportion of embryonic development that occurs above the threshold temperature for sex determination rather than the proportion of time spent above the threshold. The model predictions are borne out by experiments using the marine turtle Caretta caretta. Average developmental rates, both overall and during the period that sexual differentiation is sensitive to temperature, are unaffected by diel fluctuations about the mean incubation temperature. Sex ratios, on the other hand, were affected by diel fluctuations and ranged from ca. 100% males under regimes 26 ± 0°C and 26 ± 3°C to 100% females for regimes 26 ± 7°C and 26 ± 8°C. These and intermediate sex ratios were in close agreement with model predictions. Demonstration of an impact of temperature on sex, while holding overall developmental rate constant, gives support to hypotheses invoking a direct role for temperature rather than alternative hypotheses invoking overall developmental rate as a more proximal influence on sex. The model explains why mean temperature is a poor predictor of hatchling sex ratios. It urges caution in using “hours above the threshold” for predicting sex ratios, because 1 hr at 1°C above the threshold will not be equivalent to 1 hr at 4°C above the threshold. It provides a general framework for integrating experiments at constant temperatures with those in the field or laboratory using fluctuating regimes. It provides greater scope for exploring how reptiles with temperature dependent sex determination might respond to climatic change or other disturbances to the incubation environment. And it provides an explanation of why secondary factors such a hydric conditions and oxygen potentials might influence hatchling sex, even if temperature acts directly to influence sex ratios rather than through its influence on overall developmental rate. © Wiley‐Liss, Inc.
Hydrogen peroxide generating alcohol and aldehyde oxidases in the giant African land snail, Achatina fulica
Authors: Large Andrew T. , Connock Martin J. 
Published: June 2005

AbstractHydrogen peroxide generating alcohol oxidase (membrane bound) and aldehyde oxidase (cytosolic) were detected in tissues of the giant African land snail Achatina fulica. The highest specific activities were found in the kidney followed by the digestive gland. Solubilised digestive gland alcohol oxidase had a pH optimum of approximately 7.2. The enzyme oxidises a broad range of aromatic and aliphatic (C2C16) primary alcohols. Subcellular fractionation of digestive gland homogenate indicates that alcohol oxidase is most likely located in the endoplasmic reticulum. Cytosolic aldehyde oxidase was active with aromatic and aliphatic aldehyde but is not active with purines. A digestive role is suggested for these two enzymes. © Wiley‐Liss, Inc.
Mechanism of defensive inflation in the chuckwalla, Sauromalus obesus
Authors: Deban Stephen M. , O'Reilly James C. , Theimer Tad 
Published: June 2005

AbstractThe chuckwalla, Sauromalus obesus, avoids predation by wedging itself in a rock crevice and inflating its lungs beyond their normal inspiratory volume. Buccal and pulmonary pressures were recorded in S. obesus during defensive inflation and wedging. Maximum pulmonary pressure generated during defensive wedging was significantly higher and was achieved faster than that of nonwedging inflation. During inflation and wedging, S. obesus forces air into the lungs by pulsatile contraction of the buccal cavity. Buccal pulse pumping is an ancestral ventilation behavior of vertebrates that S. obesus uses for defensive inflation. © Wiley‐Liss, Inc.
Influence of estrogen on intermediary metabolism in a teleost, Anabas testudineus and the lizard Calotes versicolor
Authors: Kaippallil Jose D. , Oommen Oommen V. 
Published: June 2005

AbstractAdministration of different doses of estrogen (5, 10, and 25 μg) in Anabas testudineus and Calotes versicolor inhibited the activities of alanine aminotransferase and aspartate aminotransferase. In Calotes, higher doses of estrogen (10 and 25 μg) increased the activity of glutamate dehydrogenase and in Anabas it was stimulated by all three doses. The total protein and RNA were also increased by all three doses of hormone in Anabas and Calotes. Higher doses of estrogen stimulated total DNA in Anabas and Calotes and the lowest dose (5 μg) did not have any significant effect. Activities of transaminases and glutamate dehydrogenase were inhibited and the protein content decreased by the administration of actinomycin and puromycin or simultaneous administration of estrogen and protein synthesis inhibitors. Actinomycin and puromycin alone did not have any significant effect on total DNA in Anabas and Calotes. Actinomycin reduced the level of RNA and puromycin did not produce any significant effect in Calotes. In Anabas actinomycin as well as puromycin decreased total RNA content. Simultaneous administration of estrogen and these inhibitors prevented the hormone mediated increase in the level of RNA and DNA both in Anabas and Calotes. © Wiley‐Liss, Inc.