bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of a pseudocholinesterase purified from surgeonfish tissues confirms the atypical nature of this enzyme
Authors: Leibel Wayne S. 
Published: June 2005

AbstractThe sialated, presumed‐globular form of an atypical pseudocholinesterase (pseudo‐ChE) previously described from surgeonfish tissues (Leibel: Comparative Biochemistry and Physiology 1988) has been purified to apparent homogeneity using a combination of salt fractionation along with ion‐exchange and concanavalin A‐Sepharose affinity chromatographic techniques. An overall 1,400‐fold purification has been achieved with a 24% final yield of a cholinesterase (ChE) whose final specific activity is 50 μmol/min‐mg. The purified enzyme was subjected to detailed biochemical and physical analysis. The purified pseudo‐ChE is a sialated, globular, tetrameric enzyme with an apparent sedimentation coefficient of 11.5 S (± 0.5 S) and a molecular weight of 250 kilodaltons. The monomers are apparently not secured by disulfide bridges. The enzyme preferentially hydrolyzes acetyl(thio)choline but also hydrolyzes propionyl(thio)choline at reduced but comparable rates along with a wide variety of other noncholine esters. As such, it demonstrates the relative nonspecificity associated with classical pseudo‐ChEs. However, the enzyme exhibits limited, but real, substrate inhibition with all choline esters as does true acetylcholinesterase (AChE). The enzyme is insensitive to the AChE inhibitor BW 284C51, sensitive to one (RO2‐0683) of two (RO2‐1250) pseudo‐ChE inhibitors, and particularly sensitive to paraoxon inhibition (103−104‐fold more so than AChE). It exhibits the short thermal half‐life characteristic of pseudo‐ChEs but not the expected ionic activation/inhibition profile. It is clear from this and other studies of atypical extrasynaptic cholinesterase activities occuring in other vertebrates that the orthodox categorization of cholinesterase as either “true” (“specific”; E.C. 3.1.1.7) or “pseudo” (“nonspecific”; E.C. 3.1.1.8) is inadequate to accommodate the increasing instances of ChE activities that exhibit atypical, intermediate properties.
Calmodulin‐like calcium‐binding protein identified in calcium‐rich mineral deposits from freshwater mussel gills
Authors: Silverman Harold , Sibley L. David , Steffens W. L. 
Published: June 2005

AbstractExtracellular calcium concretions found in the gills of freshwater unionids are largely inorganic, containing calcium and phosphate. The organic fraction of the isolated concretions accounts for 25% of their dry weight as determined by ashing. The organic fraction of isolated concretions was examined using SDS‐polyacrylamide electrophoresis. The concretion fraction is separated into 13–14 protein bands. These bands can be further differentiated into EDTA soluble proteins and insoluble core proteins. One of the soluble proteins has a molecular weight of approximately 17,000 daltons (Da) and comigrates with authentic vertebrate calmodulin. The 17,000‐Da concretion protein cross‐reacts with sheep IgG prepared against bovine brain calmodulin as shown by immunoblot. Rabbits and mice, challenged with the entire concretion organic fraction, produce an IgG fraction which always recognizes an epitope of the 17,000‐Da protein as the major antigenic determinant. This same protein is also a calcium binding protein as shown by 45Ca autoradiography even after heat and SDS/mercaptoethanol treatment. To determine that this protein was not bound to the concretions as an artifact of the isolation procedures, immunocytochemical procedures were used to localize the antigenicity to 17,000‐Da and vertebrate calmodulin in situ. Immunocytochemical localization indicates the protein is present on the concretions in situ but documents that the majority of this protein is located in concretion‐forming cells. Electron microscopic immunocytochemistry demonstrates that the protein is found largely in early concretion‐forming cells in protein granules formed before concretion architecture is observed. This may imply that the protein is likely important in the initiation of concretion formation, and is only a residual protein as found on the extracellular concretions.
Zona‐induced acrosome reaction of hamster spermatozoa
Authors: Uto Norihiko , Yoshimatsu Nobuhiro , Lopata Alexander , Yanagimachi R. 
Published: June 2005

AbstractIt is well established that the zonae pellucidae of mature unfertilized eggs have the ability to induce the acrosome reaction of capacitated spermatozoa. To determine if this capacity of the zona is species‐specific, hamster spermatozoa were allowed to attach to the zonae of homologous and heterologous eggs and examined for the acrosome reaction. The zonae of eggs from six different species were tested and the zona of hamster egg was found to have the strongest capacity to induce the acrosome reaction of hamster spermatozoa, followed by human and rat zonae. The zonae and mouse, guinea pig, and domestic fowl eggs were incapable of inducing the acrosome reaction of hamster spermatozoa.The acrosome reaction‐inducing ability of the hamster zona was found to increase during maturation in the ovary. The zona of mature unfertilized hamster eggs maintained their acrosome reaction‐inducing ability even after aldehyde fixation or storage in a highly concentrated solution of ammonium sulfate.
Effects of photoperiod and temperature on body weight, food intake, food storage, and pelage color in the Djungarian hamster, Phodopus sungorus
Authors: Masuda Atsuko , Oishi Tadashi 
Published: June 2005

AbstractBody weight, food intake, pelage color, and testis size in Djungarian hamsters are known to show annual cycles. To analyze the environmental factors that control the annual cycle of these physiological parameters, we performed an experiment with four combinations of photoperiods and temperatures (long photoperiod and high temperature, long photoperiod and low temperature, short photoperiod and high temperature, and short photoperiod and low temperature). Short photoperiod (8L16D) induced a decrease in body weight and testis size and an increase in the ratio of food storage behavior, total hair length, and the length of white distal region of hairs (a quantitative measure of pelage color) under both low (7°C) and high (25°C) temperatures. Long photoperiod (16L8D) induced the opposite effects. Low temperature induced an increase in the amount of food intake under both long and short photoperiods. under high temperature, food intake was greater in long photoperiod than in short photoperiod. Thus, we conclude that the main environmental factor for regulating annual cycles of various parameters in the Djungarian hamster is photoperiod. Photoperiodically regulated food storage behavior seems to have an important role for the strict control of body weight and food intake.
Anaerobic and aerobic energy metabolism in brain and liver tissue from rainbow trout (Salmo gairdneri) and bullhead catfish (Ictalurus nebulosus)
Authors: Heath Alan G. 
Published: June 2005

AbstractThis study tested the hypothesis that tissue from a fish species relatively resistant to anoxia would exhibit a reduced Pasteur effect, as has been shown for some other anoxia‐resistant animals. The extent to which temperature compensation occurs in glycolysis was also examined. The production of ATP by oxidative metabolism and glycolysis was partitioned in brain and liver tissue from rainbow trout (Salmo gairdneri), an anoxia‐sensitive species, and bullhead catfish (Ictalurus nebulosus), an anoxia‐resistant species. Measurements were made under normoxic and anoxic conditions and at different temperatures, using glucose as a substrate. Oxidative metabolism (estimated by oxygen consumption) and glycolysis (estimated by lactate accumulation) under normoxic conditions exhibited relatively good temperature compensation, compared with that of anoxic glycolysis. Exposure to anoxia caused a two‐ to threefold increase in glycolysis in brain tissue but not in liver (i.e., brain exhibited a Pasteur effect). At 5°C, the Pasteur effect was lost in both species. The findings do not support the hypothesis; instead, the catfish brain tissue actually had a slightly larger Pasteur effect than did the trout. Bullhead catfish brain tissue has approximately five times the glycogen concentration of the trout. Thus brain tissue of the catfish has both a somewhat greater anaerobic scope and a much larger anaerobic capacity than does the trout.
Inhibitory and stimulatory effects of limb ectoderm on in vitro chondrogenesis
Authors: Solursh Michael , Reiter Rebecca S. 
Published: June 2005

AbstractPrevious studies have indicated possible dual effects of the limb ectoderm in cartilage differentiation. On one hand, explants from early (stage 15) wing buds are dependent on contact with the limb ectoderm for cartilage differentiation (Gumpel‐Pinot, J. Embryol. Exp. Morph. 59:157–173, 1980). On the other hand, limb ectoderm from stage 23/24 wing buds inhibits cartilage differentiation by cultured limb mesenchyme cells even without direct contact (Solursh et al., Dev. Biol. 86:471–482, 1981). In the present study, ectoderms from both stage 15/16 and stage 23/24 wings are cultured under the same conditions, and ectoderms from each source are shown to have two effects. Each stimulates chondrogenesis in stage 15 wing bud mesenchyme, and each inhibits chondrogenesis in older wing mesenchyme. The results suggest that the limb ectoderm has at least dual effects on cartilage differentiation, depending on the stage of the mesenchyme. One effect involves an early mesenchymal dependence on the ectoderm. This effect requires contact between the ectoderm and mesoderm (Gumpel‐Pinot, J. Embryol. Exp. Morphol. 59:157–173, 1980) but also can be observed at a distance from the ectoderm. Later, the ectoderm can act without direct contact between the ectoderm and mesoderm to inhibit chondrogenesis over some distance.
Acrosome‐reacted guinea pig spermatozoa become fusion competent in the presence of extracellular potassium ions
Authors: Yanagimachi R. , Bhattacharyya Amitabha 
Published: June 2005

AbstractGuinea pig spermatozoa are able to undergo capacitation and the acrosome reaction in a K+‐free (‐deficient) medium. However, they are unable to fuse with eggs unless they are exposed to a millimolar concentration of extracellular K+ during or after the acrosome reaction. Apparently, the plasma membrane over the equatorial segment gains the ability to fuse with eggs in the presence of K+ during and/or after the acrosome reaction. Once it becomes fusible, the membrane retains its fusibility even in a K+‐deficient medium. Rb+ is almost as effective as K+ in rendering the sperm membrane fusible. Li+ and Cs+ are less effective. The molecular mechanism by which K+ renders acrosome‐reacted spermatozoa fusion competent is unknown, but it may involve K+‐mediated efflux of H+ from the spermatozoa.
Prey odor discrimination by the broad‐headed skink (Eumeces laticeps)
Authors: Cooper William E. , Vitt Laurie J. 
Published: June 2005

AbstractPrey odor discrimination is highly developed in the scincid lizard Eumeces laticeps. In an experiment with a randomized blocks design in which each lizard responded to deionized water, cologne, and cricket odors (presented in counterbalanced sequence on cotton‐tipped applicators), tongue‐flick attack scores (TFAS) varied strikingly among conditions (F = 12.68; df = 2, 22; P < 0.001). Multiple comparisons revealed that responses elicited by cricket odors were stronger than those to the control stimuli (P < 0.01 each) and that responses to the two control odor were not statistically distinguishable. Eight of 12 lizards bit applicators bearing cricket odors whereas only one lizard bit in response to the other stimuli. Ability to detect and identify prey by chemical cues may be especially important in E. laticeps and other skinks that frequently consume concealed prey. That similar abilities have been described in E. fasciatus and Scincella lateralis and suggested in E. inexpectatus may indicate that prey odor discrimination is widespread in Scincidae.TFAS, a composite of tongue‐flicking, biting, and latency to bite, had a strong negative linear relationship with latency to bite (r = −0.92; F = 56.36; df = 1, 10; P < 0.0001) and a suggestive but nonsignificant relationship with number of tongue‐flicks (r = −0.51; F = 3.56; df = 1, 10; P = 0.088).
Pharmacological doses of thyroxine simulate the effects of increased daylength, and thyroidectomy, decreased daylength on the reproductive system of European starlings
Authors: Dawson A. 
Published: June 2005

AbstractIntact male starlings, thyroidectomized male starlings, and intact male starlings treated chronically with pharmacological doses of L‐thyroxine were kept on four different daylengths, 8 hr of light : 16 hr of darkness per day (8L : 16D), 9.5L : 14.5D, 11L : 13D, or 13L : 11D. Changes in testicular size, molt, and plasma thyroxine concentrations were monitored for 18 weeks. In all three treatments, initial testicular growth rates increased with daylength. On all four daylengths, treatment with thyroxine increased initial testicular growth rates above those of intact birds. Thyroidectomy decreased testicular growth rate on 13L : 11D. Intact birds on 13L : 11D, and thyroxine‐treated birds on 13L : 11D, 11L : 13D, and some on 9.5L : 14.5D, became photorefractory and molted. The results demonstrate that treatment with thyroxine simulates a long day and, conversely, that thyroidectomy simulates a short day. This may be due to an effect on the photoperiodic clock. However, the changes in plasma thyroxine concentration necessary for this far exceed the normal physiological range. Thus, photoperiodically induced changes in reproductive function are not mediated by thyroxine.
Effects of in vitro incubation on a zona binding site found on murine spermatozoa
Authors: Boettger Holly , Richardson Richard , Free Donna , Rushing Sabrina , Poirier Gary R. 
Published: June 2005

AbstractMurine cauda epididymal sperm possess a site, the acceptor, on the plasma membrane over the apical cap region of the acrosome which recognizes both a proteinase inhibitor of seminal vesicle origin and homologous zonae. The acceptor site may participate in both capacitation and zona binding. This presentation explores the effect of in vitro incubation in a medium known to induce capacitation on the binding capabilities of this site.Approximately 80% of fresh cauda epididymal sperm will bind the seminal inhibitor in vitro. Incubating sperm, pretreated with inhibitor for 2 hr in a medium (M199‐M) known to support capacitation, reduces by 60% the number of sperm showing evidence of the inhibitor. No such decrease is seen when sperm are incubated in a medium (M199) that does not support capacitation. During the 2‐hr incubation in either medium, 60–70% of the sperm retain two diverse components on the plasma membrane over the acrosome: a receptor for the Fc portion of IgG and an epitope recognized by a monoclonal antibody to the acceptor site. These observations suggest that the plasma membrane in the acrosome region of the cell remains structurally intact during incubation. Furthermore, sperm retain the ability to bind the seminal inhibitor during incubation. After a 2‐hr incubation in M199‐M, sperm pretreated with heat‐solubilized zonae no longer bind the inhibitor. These sperm, however, retain the plasma membrane over the acrosomal cap region. When the sperm are incubated in M199, no decrease in inhibitor binding due to zona treatment is noted. The data suggest that the incubation in M199‐M modifies the sperm such that they are able to bind solubilized zona.
Structure, function, and central projections of the MC1 chordotonal organ in the crayfish Cherax destructor (Crustacea: Decapoda: Astacura)
Authors: Lupone Daniela , Macmillan David L. 
Published: June 2005

AbstractThe morphology and physiology of the MC1 mero‐carpopodite organ of the crayfish Cherax destructor was compared with those of the better known northern hemisphere species and found to be closely similar. The nerves to the organ were prepared using a fine dissection technique and backfilled with Cobalt chloride to reveal the central endings. This first description of the central endings of a crayfish proprioceptor reveals that it has relatively restricted distribution in the ventral, ipsilateral hemiganglion. The similarity with results from insects is discussed.
Lack of proliferative response in denervated, reamputated limb regenerates of larval Ambystoma
Authors: Winner Cherie Olsen 
Published: June 2005

AbstractThis paper describes the response of early four‐digit regenerates of axolotls to reamputation and denervation. Reamputation of innervated regenerates led to sharp increases in 3H‐thymidine labeling index (LI) and mitotic index (MI) on days 2–5 post‐reamputation. This resembles the response of innervated limbs following initial amputation. Regenerates that were denervated at the time of reamputation exhibited no proliferative response through day 5. This is in marked contrast to denervated, original amputation limb stumps, in which LI and MI rise for several days (as in innervated stumps) before falling to background levels. Although myelin was scarce near the level of reamputation, the lack of proliferation cannot be explained solely on that basis. The results are consistent with the possibility that the “neurotrophic factor” that causes stump and blastema cell mitosis is not present in unamputated limbs but is made in response to amputation.
Monitoring of metabolic responses of intact Haliotis (abalones) under salinity stress by 31P surface probe localized NMR
Authors: Higashi Richard M. , Fan Teresa W.‐M. , Macdonald Jeffrey M. 
Published: June 2005

AbstractSurface probe localized 31P NMR spectroscopy was employed to record the metabolic responses of the foot of intact Haliotis cracherodii and H. rufescens (black and red abalones) under hyper‐ and hypoosmotic stresses. Use of the surface probe allowed spectral localization on the foot of intact abalones, facilitated monitoring of different sizes of animals, and minimized constraints on aquatic chamber design normally imposed by homogeneous‐field probes. Generally, hyperosmotic stress (51‰) elicited more rapid changes of phosphate metabolites than hypoosmotic stress (17‰). As with the well‐studied hypoxic stress in intact mammalian and excised molluscan tissue, both salinity treatments caused drops in the phosphagen and increases in inorganic phosphate levels. However, osmotic stress was distinct from hypoxic stress inthat intracellular pH did not change and nucleotide triphosphate (NTP) concentrations dropped immediately. Although these findings are preliminary, they demonstrate the utility of the surface probe approach for studies of environmental stress in intact marine invertebrates.
Physiological doses of Epinephrine in the human: Chronotropic but not hyperglycemic or catecholaminotropic
Authors: Epple August , Bertoni John M. , Hathaway Charles B. 
Published: June 2005

AbstractSingle physiological doses of epinephrine did not affect the blood sugar level of human volunteers though they caused a marked tachycardia that was accompanied by a strong transient sensation, typically described as fullness in the chest. Epinephrine did not cause the release of norepinephrine and/or dopamine in man, in contrast to three other vertebrates (lamprey, eel, and rat). In the human, as in the rat and cyclostomes, the glycemic effect of epinephrine occurs only during stress and/or unphysiological conditions, while the chronotropic effects are probably physiological from cyclostomes to man.
Timing of spermatogenesis and spermiation in snails Helix aspersa bred under short photoperiods: A histologic and quantitative autoradiographic study
Authors: Griffond Bernadette , Medina Antonio 
Published: June 2005

AbstractAfter a long hibernation, snails Helix aspersa were reactivated and maintained under either long (LD 18:6) or short (LD 8:16) photoperiods. Twenty days after activation, they were injected with [3H]thymidine in order to estimate the duration of spermatogenic stages under both conditions. Whereas the spermatogonium and spermatocyte I stages prove to have the same duration under both short and long photoperiods, the male cells stay longer at spermatocyte II stage in short‐day snails. In these animals, spermiogenesis proceeds normally and its duration is similar to that in long‐day snails. Therefore, in the course of Helix aspersa spermatogenesis, two phases are particularly sensitive to the photoperiod: spermatogonial proliferation and transition from spermatocyte II to spermatid. Gradual decrease of the levels of [3H]thymidine in the gonad of long‐day snails from the 6th week may be interpreted as being due to release of labeled sperm; in short‐day snails, these levels remain nearly unchanged to the end of the experiment, which indicates that the temporary blockade of spermatogenesis at the completion of spermatocyte II results in a delay in spermiation.
Chloride current modulation during meiosis in Xenopus oocytes
Authors: Vilain J. P. , Moumene M. , Moreau M. 
Published: June 2005

AbstractUsing the voltage clamp technique, the calcium‐dependent transient outward chloride current in Xenopus oocytes was monitored during in vitro meiotic maturation induced by progesterone. This Cl conductance increased during the first 5–8 hours following progesterone stimulation. It then decreased until germinal vesicle breakdown (GVBD). Before GVBD, the Cl conductance could be activated by A23187 ionophore. After GVBD, the transient current totally disappeared, and only a single voltage‐gated current could be observed.
In vitro technique for studying garter snake (Thamnophis sp.) development
Authors: Holtzman David A. , Halpern Mimi 
Published: June 2005

AbstractGarter snake (Thamnophis sp.) embryos of different embryonic ages were explanted from pregnant females and grown in vitro for up to 35 days. The culture medium consisted of Eagle's Minimum Essential Medium with various organic and inorganic supplements and antibiotics. Cultured embryos were injected with tritiated thymidine, sacrificed, and processed for autoradiographic examination. The in vitro technique allowed direct visualization of external morphologic changes over time, which followed a timetable similar to that of embryos growing in vivo. This technique also allowed easier manipulation of embryos for determination of embryonic stage and for injection of tritiated thymidine. This is the first report of long‐term culture of snake embryos which adds to the limited number of reptilian embryos that have been studied in vitro.
pH in eggs of the ascidian Ciona intestinalis at fertilization and activation
Authors: Russo P. , Pecorella M. A. , De Santis A. , Dale B. 
Published: June 2005

AbstractUsing liquid ion exchanger microelectrodes, we have measured the intracellular pH of unfertilized ascidian eggs. The pH in these eggs ranges from 7.1 to 7.6 (similar to values for fertilized sea urchin eggs) and does not change during the first 7 minutes of activation, whether induced by spermatozoa or by the Ca2+ ionophore A23187. Factors regulating metabolic derepression in regulative and mosaic eggs are discussed.