bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a pseudocholinesterase purified from surgeonfish tissues confirms the atypical nature of this enzyme
Authors: Leibel Wayne S.
Published: June 2005

The 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

Extracellular 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

It 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

Body 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

This 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

Previous 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

Guinea 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

Prey 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

Intact 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

Murine 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

The 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

This 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

Surface 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

Single 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

After 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

Using 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

Garter 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

Using 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.
Cytochalasin D‐induced triploidy in the mouse
Authors: Speirs S. , Kaufman M. H.
Published: June 2005

Previous attempts to obtain digynic triploid mouse development in vivo have either been entirely or only marginally successful, generally with the production of heteroploid rather than triploid conceptuses. We report that when a single intraperitoneal injection of 15 üg of cytochalasin D is given to recently mated female mice during a restricted period following ovulation induced by exogenous gonadotrophins, between 14 and 18% of conceptuses isolated on the 10th day of gestation had a triploid chromosome constitution. Triploidy was only induced in those eggs that were exposed to cytochalasin D when they were passing through a critical phase of the second meiotic division corresponding to the time when the second polar body was about to be extruded. Exposure to this agent either before or after this critical period only results in the development of normal diploid conceptuses. When females were mated to males carrying an easily recognisable paternally derived ‘marker’ chromosome, convincing cytogenetic evidence was obtained that only digynic triploidy was induced. No examples of diandric triploidy were recognised when conceptuses were analysed on the 10th day of gestation. The technique described therefore represents a simple and direct means of inducing digynic triploid mouse conceptuses whose development potential may be compared directly with that of their normal diploid littermates.
Induction of the acrosome reaction in goat spermatozoa in simple physiological salt solution
Authors: Kusunoki Hiroshi , Kato Seishiro , Kanda Sunao
Published: June 2005

The present study was carried out to determine whether K+, Mg2+, PO43−, and HCO3− in a medium are necessary for inducing the acrosome reaction in ejaculated goat spermatozoa. Washed goat spermatozoa were resuspended in K‐1 medium, containing NaCl, KCl, CaCl2, MgCl2, NaH2PO4, and NaHCO3; in K‐2 medium, containing NaCl, CaCl2, NaH2PO4, and NaHCO3; in K‐3 medium, containing NaCl, CaCl2, and NaHCO3; and in K‐4 medium, containing only NaCl and CaCl2, followed by preincubation in a sealed glass tube at 39.5°C for 1, 2, or 3 h. The sperm acrosome reaction was evaluated by the trypan blue‐Giemsa method and hamster test. The results were essentially the same in all cases. Following preincubation for 1 h, however, the percentage of acrosome‐reacted spermatozoa, the proportion of zona‐free hamster eggs penetrated by spermatozoa, and the average number of spermatozoa in the vitellus of these penetrated eggs were low; all values indicated a significant increase with preincubation for 2 and 3 h. The presence of K+, Mg2+, PO43−, and HCO3− in the medium thus does not appear necessary for inducing the acrosome reaction in goat spermatozoa, since they can undergo the reaction during preincubation in a simple physiological salt solution containing only NaCl and CaCl2 when preincubated in sealed glass tubes at 39.5°C.
Proteolytic activity of specialized surface protrusions formed at rosette contact sites of transformed cells
Authors: Chen Wen‐Tien
Published: June 2005

Surface protrusions at the leading edge of a moving cell that make contact with the surrounding extracellular matrix (ECM) are its main motor for locomotion and invasion. Chicken embryonic fibroblasts transformed by Rous sarcoma virus (RSV‐CEF) form specialized membrane rosette‐shaped contact sites on planar substrata as shown by interference reflection microscopy (IRM). Such activity is lacking in normal cells. These rosette contacts are more labile than other adhesion sites, such as focal and close contacts. Ultrastructural studies demonstrate that rosettes are sites at which membrane protrusions from the ventral cell surface contact the substratum. These protrusions are filled with meshworks of microfilaments and contain the pp60src oncogene product, actin, vinculin, and α‐actinin. However, unlike focal contacts, at the rosettes these proteins interact to extend a highly motile membrane. Rosettes have the biological activity of degrading ECM components, as demonstrated by (1) local degradation of fibronectin substrata at sites of rosette contacts, but not focal and close contacts; (2) localization of putative antiprotease antibody at sites of rosette contacts, but not at focal an close contacts; and (3) local disruption of fibronectin matrix at sites of protrusive activity seen by transmission electron microscopy (TEM). In addition, formation of the rosette contact is insensitive to the ionophore monensin, and to inhibitors of proteolytic enzymes, while local fibronectin degradation at rosette contacts is inhibited by inhibitors of metalloproteases, 1,10‐phenanthroline and NP‐20. I consider these membrane protrusions of the rosette contacts in RSV‐transformed cells specialized structural entities—invadopodia—that are involved in the local degradation of the ECM.
Oxygen affinity of monotreme blood: Hypoxic adaptations
Authors: Lutz P. L. , Dawson T. J. , Bonnet E. , Fanning D.
Published: June 2005

Whole‐blood oxygen affinity was measured for the duck‐billed platypus and the echidna. For the platypus, p50 was 26.8 Torr O2 at pH 7.4, PCO2 = 36 Torr, and 32.0°C. The H+ Bohr coefficient was −0.286 and was oxygen saturation‐independent. However, at elevated PCO2 (69 Torr) the H+ Bohr effect declined markedly at saturation values below 60%. No specific effect of CO2 on the p50 echidna whole blood was found. In the echidna, p50 was 24.0 Torr O2 at pH 7.4, PCO2 = 36 Torr, and 32.0°C. The H+ Bohr effect was −0.280 and was also saturation‐independent. By contrast, a substantial specific CO2 effect on blood O2 affinity was found (Δlog p50/Δlog PCO2 = 0.114). These data are related to the habitat and mode of life of the respective species.
Autonomous death of amphibian (Xenopus laevis) cranial myotomes
Authors: Chung Hae‐Moon , Neff Anton W. , Malacinski George M.
Published: June 2005

The death of cranial myotomes during Xenopus laevis embryogenesis is employed as a model system to study programmed cell death. The first primary myotomes to differentiate and functionally develop are in the occipital region of the embryonic head. Between stages 27 (tailbud) and 48 (feeding tadpole), they degenerate and disappear in a craniocaudal sequence. Descriptive and experimental studies were undertaken to establish whether this apparent cell (myotome) death program is autonomous or whether it depends on interactions with surrounding tissues (e.g., otic vesicle). Removal of the adjacent otic vesicle did not affect cranial myotome death. Likewise, grafting the otic vesicle to a novel location along the somite file did not induce local myotome degeneration (death). Cranial myotome primordia grafted into the trunk region degenerated on schedule. Trunk myotome primordia grafted to the cranial myotome location did not degenerate. It is therefore concluded that the cranial myotome death program has become autonomous by the time the cranial myotomes reach the developmental stage of segmentation.
Differentiation of the golden hamster oviduct epithelial cells during postnatal development: An electron microscopic study
Authors: Abe Hiroyuki , Oikawa Taneaki
Published: June 2005

The ultrastructural changes in the process of differentiation of the epithelial cells of the golden hamster oviduct during postnatal development were investigated by means of electron microscopy. In the epithelium of the ampulla of the neonatal oviducts, no differentiated ciliated cells or secretory cells were identified. In these undifferentiated cells, free ribosomes were well developed, but rough endoplasmic reticulum (RER) and the Golgi apparatus were undeveloped. Cells undergoing ciliogenesis were first identified at 3.5 days after birth, and some ciliated cells appeared at 4.5 days. In the nonciliated cells, marked changes in the organelles were observed at this time. Subsequently, some nonciliated cells containing well‐developed RER and Golgi apparatus were obsrved at 9.5 to 10.5 days after birth, and a few mature secretory cells were observed at 10.5 days. An increase in secretory granules occurred in the secretory cells at 12.5–15.5 days after birth. Many fully mature ciliated and secretory cells were observed at 15.5 days after birth. After 20.5 days after birth, the epithelium was identical with that of the adult golden hamster. Quantitative data indicated that the differentiation of ciliated cells began earlier and took place over a more extended period of time than did that of the secretory cells in the golden hamster oviduct during postnatal development.
FMRF‐amide immunoreactivity and the midgut of the corn earworm (Heliothis zea)
Authors: Jenkins Alan C. , Brown Mark R. , Crim Joe W.
Published: June 2005

The midgut of the larval corn earworm, Heliothis zea, was examined using light microscopy and immunocytochemistry. Many endocrine‐like midgut cells exhibit immunoreactivity to the molluscan cardioactive peptide FMRF‐amide (FMRFa), and bovine pancreatic polypeptide (BPP). Cross‐reactivity studies demonstrate the immunoreactive material is more FMRFa‐like than BPP‐like. Immunocytochemical surveys and radioimmunoassay of midguts from fed or starved individuals show that the fed animals contain a significantly greater amount of FMRFa immunoreactivity. Radioimmunoassay of hemolymph reveals a significant increase in the amount of FMRFa immunoreactivity in the starved animals. These observations indicate that the changes in the levels of FMRFa immunoreactivity in the midgut and hemolymph may be a midgut endocrine response to changes in the feeding state.
Neuropeptide stimulation of thyrotropin secretion in the larval bullfrog: Evidence for a common neuroregulator of thyroid and interrenal activity in metamorphosis
Authors: Denver Robert J. , Licht Paul
Published: June 2005

The effects of several neuropeptides on in vitro thyrotropin (TSH) secretion by pituitaries of the frog Rana catesbeiana were studied at two stages of development. The relative concentration of TSH secreted into the medium was determined by bioassay using in vitro thyroxine (T4) production by thyroids from adult grass frogs, Rana pipiens. Pituitaries from tadpoles in Taylor‐Kollros stages 17–19 responded to doses of ovine corticotropin‐releasing hormone (CRH) ranging from 10 to 1,000 ng/ml; the same glands did not respond to doses of thyrotropin‐releasing hormone (TRH) between 10 and 1,000 ng/ml. A single dose of 1,000 ng/ml rat growth hormone‐releasing hormone (GHRH) had no effect on TSH release. Pituitaries from postmetamorphic frogs (stage 25) exposed to 1,000 ng/ml ovine CRH secreted concentrations of TSH that were higher on average than controls (four of seven responded), and two of seven responded to 100 ng/ml TRH. These observations raise the possibility for a common central regulator of the thyroid and interrenal axes in metamorphosis in which a CRH‐like molecule might act as an important neuroendocrine stimulus for both corticotropin and thyrotropin secretion. Furthermore, these and previous results with several species of adult anurans (R.J. Denver: Gen. Comp. Endocrinol., 72:383–393) suggest that pituitary TSH responsiveness to TRH develops in frogs after metamorphic climax.
Delayed carpal ossification in N. viridescens efts: Relation to the progress of mesopodial completion in newt forelimb regenerates
Authors: Libbin Richard M. , Mitchell Ormond G. , Guerra Ladislao , Person Philip
Published: June 2005

The persistence of cartilage in the adult newt (Notophthalmus viridescens) forelimb skeletal regenerate has recently been reported by Libbin et al. (J. Exp. Zool., 248:238–242, '88). It is particularly evident in the carpal group, which remains cartilaginous for at least 9 months while all other regrown skeletal parts are either ossified or ossifying. The present investigation was undertaken to determine whether delayed ossification in the adult regenerate recapitulates a pattern evident during the development of the forelimb of the red eft (N. viridenscens' immature terrestrial phase). Right upper limbs of 20 efts were examined at low magnification to establish carpal composition and organization. Among five efts of smallest size (26.54 ± 2.20 mm snout‐to‐vent length), and displaying bright orange dorsal skin coloration, all carpal rudiments were cartilaginous. Eleven efts, intermediate in length (33.88 ± 0.81 mm), and primarily of orange‐tan color, presented a varying pattern of mesopodial ossification characterized by the appearance of centers within some or all carpals. In the largest‐size group (39.23 ± 0.86 mm), displaying orange‐green coloration, all carpals had ossified. These observations demonstrate that during adult newt forelimb regeneration, the failure of the carpal elements to begin ossification in synchrony with other regrown skeletal parts duplicates a similar schedule of delayed mesopodial ossification which is evident during the development of the red eft's forelimb.
Size‐dependent responses to dehydration in the terrestrial slug, Limax maximus L.: Locomotor activity and huddling behavior
Authors: Welsford Ian G. , Banta Pamela A. , Prior David J.
Published: June 2005

When specimens of Limax maximus L. are dehydrated alone or in groups of three or five, they exhibit an increase in locomotor activity but no increase in huddling behavior (i.e., the formation of aggregations of several slugs) when compared with hydrated animals. The extent of the dehydration‐induced increase in locomotion is a function of body size, with small and mediumsized animals (0.3–2.9 g) exhibiting significantly more activity than large animals (3.5–6.0 g). The dehydration‐induced behavioral responses of small slugs are affected by altering the rate of dehydration. Therefore, the variation in behavioral responses between L. maximus of different sizes may be due to the different rates of dehydration that they experience.
Biochemical adaptations to diving in the common murre, Uria aalge, and the Atlantic puffin, Fratercula arctica
Authors: Davis M. Benjamin , Guderley Helga
Published: June 2005

To evaluate whether specialized biochemical adaptations facilitate the extensive breath‐hold capacities of diving alcids, we compared several such parameters in three locomotor muscles of the common murre, Uria aalge, and the Atlantic puffin, Fratercula arctica, with those in the corresponding muscles of two terrestrial species, the pigeon, Columbia livia, and the pheasant, Phasianus colchicus. The pheasant and pigeon were chosen since they provide recognizably different patterns of biochemical support for flight. The pectoral, supracoracoideus and sartorius muscles were examined since they are the major locomotor muscles. The biochemical modifications which distinguish alcid muscles from pigeon muscles are subtle but include greater hexokinase activities in pigeon muscles, greater myoglobin levels in alcid muscles, and differences in the intraspecific ranking of the muscles' capacities for glycolysis from glycogen. By contrast, the capacities for glycolysis from glycogen, the buffering capacities, and the regulatory properties of pyruvate kinase of these muscles are similar in alcids and pigeons. We conclude that diving does not require major modifications of the overall metabolic design of muscle used by a bird which is capable of sustained aerobic flight. On the other hand, the biochemical differences between pheasants and alcids are more pronounced. Pheasant pectoral has a higher capacity for glycolysis from glycogen than any of the other muscles. Flight muscles in pheasants have higher buffering capacities than those in alcids. Clearly the glycolytic specialization of pheasant flight muscles is not shared by alcid flight muscles. Thus, we suggest that alcids do not rely upon glycolysis to any considerable extent during flight or diving.
Effects of starvation and neuroactive drugs on feeding in Caenorhabditis elegans
Authors: Avery Leon , Horvitz H. Robert
Published: June 2005

Caenorhabditis elegans concentrates its food, bacteria, by pharyngeal pumping. The rate of pumping is affected by the presence of bacteria. Using a new assay that allows measurement of pumping rate in a population of worms suspended in liquid by measuring their uptake of microscopic iron particles, we have confirmed and quantitated this effect. Furthermore, we demonstrated that starvation stimulates pumping. Worms that had been deprived of bacteria for more than 4 hours pumped in the absence of bacteria under conditions in which well‐fed worms did not. Furthermore, starved worms responded to lower amounts of bacteria than did fed worms.

The assay was also useful for measuring effects of drugs on pumping. Of about 30 chemicals screened, 5 had clear effects. The neurotransmitter serotonin and the serotonin uptake inhibitor imipramine stimulated pumping, while the serotonin antagonist gramine inhibits. Imipramine stimulation is greatly decreased in cat‐1 and cat‐4 mutants, which have low levels of serotonin. Muscimol, an agonist for the neurotransmitter GABA, and ivermectin, whose site of action may also be the GABA receptor, both inhibit pumping. Qualitative observations suggested a role for acetylcholine in the regulation of pumping.
Biochemical study of prolactin binding sites in Xenopus laevis brain and choroid plexus
Authors: Muccioli Giampiero , Guardabassi Antonietta , Pattono Paola
Published: June 2005

The occurrence of prolactin binding sites in some brain structures (telencephalon, ventral hypothalamus, myelencephalon, hypophysis, and choroid plexus) from Xenopus laevis (anuran amphibian) was studied by the in vitro biochemical technique. The higher binding values were obtained at the level of the choroid plexus and above all of the hypothalamus. On the bases of hormonal specificity and high affinity, these binding sites are very similar to those of prolactin receptors of classical target tissues as well as of those described by us in other structures from Xenopus. To our knowledge, the present results provide the first demonstration of the occurrence of prolactin specific binding sites in Xenopus laevis choroid plexus cells.
Further observations on the association between lipid metabolism and low embryo hatchability in eggs from young broiler birds
Authors: Yafei N. , Noble R. C.
Published: June 2005

Comparisons have been made of the lipid compositions of the yolk contents, yolk sac membrane, plasma, and liver of chick embryos at days 14 and 19 of incubation from young (23 week) and mature (35 week) hens. A reduced yolk lipid absorption displayed by embryos from the young parents at day 19 of incubation was accompanied by lower plasma and liver lipid concentrations. As shown by electron microscopy, there was an obvious reduction in cystolic accumulation of lipid within the liver. The reduced yolk lipid concentration in embryos from the young hens was associated with lower levels of plasma low‐density lipoproteins and an alteration in the relative proportions of the major plasma lipid fractions. The altered yolk, plasma, and liver lipid concentrations are discussed with respect to values for embryos from mature hens.
Comparative study on glucose‐6‐phosphate dehydrogenase from rabbit tissues
Authors: Ninfali Paolino , Palma Fulvio
Published: June 2005

The activity of glucose‐6‐phosphate dehydrogenase (G6PD) was measured in bone marrow, spleen, lung, liver, kidney, adipose tissue, brain, heart, muscle, and in the erythroid cell line of rabbit. In tissues, the activity ranged from 6.87 to 0.09 U/g wet tissue, found in bone marrow and muscles, respectively, whereas in the erythroid cell line it ranged from 14.3 to 2.4 U/g cells for erythroblasts and erythrocytes, respectively. The electrophoretic patterns of the tissue crude extracts shoed an identical set of three activity bands, and the immunotitration curves obtained with rat antirabbit erythrocyte G6PD antibodies shared the same equivalence point. The enzyme, purified to homogeneity from different tissues, showed no significant differences among the Km values for NADP and G6P. The results give a picture of the variability of the G6PD activity in rabbit tissues and suggest the presence of the same enzyme molecule in each tissue.
In the Mexican salamander (Ambystoma mexicanum) homozygous for the gene eyeless, unilateral neural fold rearrangements stimulate bilateral eye formation
Authors: Brun Rudolf B.
Published: June 2005

The objective of the present investigation was to test the hypothesis that the absence of eyes in the eyeless mutant Mexican salamander (Ambystoma mexicanum) might be caused by an antero‐posterior morphogenetic system out of balance in the head of the mutant. To test this hypothesis the antero‐posterior sequence of the neural fold of eyeless mutant neurulae was rearranged in two ways: unilateral grafting of posterior neural fold tissues from mutant donors into the anterior nasal area of mutant hosts (and vice‐versa) was performed; and in addition, the eye region of the mutant was moved into posterior temporal positions as well as shifted forward into the nasal area. The results of these experiments demonstrate that larvae homozygous for the eyeless mutant gene are capable of forming eyes in vivo following such antero‐posterior rearrangements of their neural folds. In addition, operations performed unilaterally had a bilateral effect: eye structures differentiated on the operated as well as on the unoperated side of the larvae. These results suggest that the eyeless mutant fails to form eyes because of an inhibitory effect on the optic vesicles emanating from neighboring tissues, not because of an inherent defect in the neural plate to form retina.
Ketone body and phosphoenolpyruvate formation by isolated hepatic mitochondria from Squalus acanthias (spiny dogfish)
Authors: Anderson Paul M.
Published: June 2005

In elasmobranchs, triglycerides are stored in the liver, which appears to be the primary site for lipolysis and oxidation of fatty acids, a major product being ketone bodies. The objective of this study was to obtain comparative information about properties of ketone body and phosphoenolpyruvate formation by liver of Squalus acanthias (spiny dogfish, a representative elasmobranch) by using an isolated hepatic mitochondrial system we have previously described for studying respiration and glutamine‐dependent citrulline synthesis. Acetate and palmitoyl‐CoA are stoichiometrically converted to ketone bodies at a rapid rate. The capability of mitochondria to convert short‐chain fatty acids to ketone bodies indicates that the previously reported inability of dogfish mitochondria to utilize short‐chain fatty acids to support respiration is not due to absence of nucleoside monophosphate kinase activity. At least two acyl‐CoA synthetase activities are present in mitochondrial extracts, one specific for acetate and another with specificity for longer‐chain fatty acids. Utilization of palmitoyl‐CoA is carnitine‐dependent and is inhibited by low concentrations of malonyl‐CoA. Pyruvate and alanine are also rapidly metabolized to ketone bodies. Phosphoenolpyruvate is formed at a significant rate from a number of substrates, including in particular aspartate and malate in the presence of α‐ketoglutarate. The osmolytes urea and trimethylamine oxide activate and inhibit, respectively, phosphoenolpyruvate formation; in contrast, these osmolytes inhibit and activate, respectively, ketone body and citrulline formation by isolated mitochondria. The results are consistent with the reported unique functions of dogfish liver in lipid metabolism and indicate that the basic enzymatic processes at the level of mitochondria appear to be analogous to those present in mammalian species.
Characteristics of the progression of squamation and the formation of ctenii in the Japanese flounder, Paralichthys olivaceus
Authors: Kikuchi Shin‐Ichi , Makino Naoshi
Published: June 2005

The progression of squamation and the formation of ctenii in developing juveniles of completely ambicolorate specimens of the Japanese flounder, Paralichthys olivaceus (Temmink et Schlegel), have been examined and compared with those of normally colored fish. The squamation developed with a similar pattern on both the ocular and blind sides of completely ambicolorate fish and of normal fish. In the normal fish, formation of ctenii occurred only on the ocular side and not on the blind side. In the completely ambicolorate fish, the formation of ctenii occurred on both the ocular and the blind side, but the formation of ctenii on the blind side differed from that on the ocular side in both normal and completely ambicolorate fish in terms of both mode and pattern. On the blind side of ambicolorate fish, the formation of ctenii progressed not from the lateral axis as is the case in the normal fish, but from the dorsal and ventral edges just after the formation of ctenii reached the edges on the ocular side, suggesting the diffusion of an unknown factor(s) through the dermal tissue.