bluuebunny/crossref_metadata_2025 huggingface dataset:
Invertebrate red blood cell carbonic anhydrase
Authors: Henry Raymond P.
Published: June 2005

This is the first report documenting the presence of carbonic anhydrase (CA) for any invertebrate red cells. CA activity was measured in plasma, hemolysates of blood cells, and in hemolymph of selected species of invertebrates. Annelid red blood cells (RBC) and sipunculid pink blood cells both possessed significant levels of CA activity. Molluscan RBC, on the other hand, lacked CA activity. The distribution appears to have fallen along phylogenetic lines, with CA being present only in blood cells of the two more closely related groups. However, the presence of extracellular CA was confirmed in oyster hemolymph. Oyster hemolymph CA showed a similar affinity (Ki) for the sulfonamide inhibitors acetazolamide and ethoxzolamide, as did the vertebrate RBC CA II isozyme, supporting the idea that this isozyme could be the ancestral form of the enzyme.
Maternal calcium contribution to glochidial shells in freshwater mussels (Eulamellibranchia: Unionidae)
Authors: Silverman Harold , Todd Kays W. , Dietz Thomas H.
Published: June 2005

Previous work has demonstrated that calcium concretions, located in the gills of freshwater mussels, disappear during the reproductive season. While calcium is being mobilized, there is no increase in calcium content in the blood. The current study documents the passage of maternal calcium to glochidia, for the production of calcium carbonate shells while the larvae are brooding in the water channels of the lateral gills; 45Ca was injected into Anodonta grandis 2 mo before the onset of reproduction and the label was distributed through the animal but was concentrated largely in the calcium concretions. Following glochidia development, 45Ca was found incorporated in the shell of the embryos. To determine the extent of the maternal passage of calcium to the embryos, Ligumia subrostrata containing embryos undergoing shell formation were exposed to 45Ca, either by injection into the blood or by inclusion of label in the bathing medium. The amount of label found in the developing glochidia is proportional to the 45Ca content in the blood of the maternal animal. Isolated glochidia directly exposed to label will adsorb 45Ca onto their shells, but there is little addition of label to glochidia in intact maternal gills during the bath exposure experiments. The results indicate that the maternal contribution of 45Ca is over 90%, with direct contribution from the bathing medium accounting for less than 8%. These results indicate that the branchial water channel in which the embryos are developing is isolated from bath 45Ca. This study presents morphological evidence that the physiological isolation of glochidial shells from bath 45Ca is due to a rearrangement of water channel morphology, and that the chamber, in which the embryos develop, has no contact with the bathing medium.
Specificity of sperm‐binding Wolffian duct proteins in the rooster and their persistence on spermatozoa in the female host glands
Authors: Morris S. A. , Howarth B. , Crim J. W. , de Cordoba S. Rodriguez , Esponda P. , Bedford J. M.
Published: June 2005

Unlike those of mammals, chicken spermatozoa can develop their fertilizing ability before they leave the testis to pass into the Wollfian duct; moreover, chicken spermatozoa do not require a period of capacitation in the female tract. A question arises, therefore, as to the significance of secretory proteins shown to bind to the surface of chicken spermatozoa as they pass into and through the Wolffian duct. Using anti‐Wolffian duct fluid IgG as a probe visualized by immunoperoxidase staining, the present investigation confirms that testicular spermatozoa of quail and turkey as well as chicken do not have any surface determinants in common with those present in Wolffian duct secretions. By contrast, those in the lower portion of the vas deferens display a strong reaction with anti‐Wolffian fluid IgG over their entire surface, and immunoprecipitation studies suggest that this reflects the binding of four Wolffian duct proteins. Since a reaction to the antichicken fluid IgG is shown also by mature quail and turkey, but not duck and pigeon spermatozoa, the Wolffian components that coat spermatozoa in birds appear to have a specificity confined to the same order, in this case the Galliformes. Following vaginal or intramagnal insemination, spermatozoa present 48 hours later in the uterovaginal host glands and infundibulum glands, respectively, still reacted strongly. This finding that Wolffian duct components persist on the surface of spermatozoa in the female tract is consistent with the possibility that they have some role in sperm storage or survival in female birds.
Chromatin decondensation and DNA synthesis in human sperm activated in vitro by using Xenopus laevis egg extracts
Authors: Brown David B. , Blake Emily J. , Wolgemuth Debra J. , Gordon Katherine , Ruddle Frank H.
Published: June 2005

An in vitro sperm activation system was used to study nuclear swelling‐chromatin decondensation and DNA synthesis; processes that occur in vivo following fertilization. Lysolecithin‐permeabilized human sperm were incubated in Xenopus laevis egg extract and examined by using phase‐contrast light microscopy, electron microscopy, and autoradiography. During a 3‐hour incubation, the activated sperm nuclear chromatin underwent a decondensation‐recondensation cycle during which DNA was synthesized. This also occurred when egg extract was given a 3‐hour preincubation before the addition of the sperm, suggesting that the factor(s) required for initiating the decondensation‐recondensation cycle is associated with the sperm. Because both nuclear swelling and DNA synthesis were found to be reproducible and quantifiable, we studied the effect of various agents on the two processes, characterizing the critical component(s) in the egg extract that induces these events. EGTA was found to have no effect on the induced nuclear swelling or DNA synthesis that occurs in the activated sperm. Freezing and thawing the extract or treating the extract with aphidicolin also had no effect on subsequent nuclear swelling; however, the DNA synthesis activity was blocked. Sperm incubated in extract treated with alkaline phosphatase (AP) had both nuclear swelling and DNA synthesis blocked. However, if the sperm were pretreated with DTT, and then incubated with the AP‐treated extract, only the DNA synthesis activity of the extract was blocked. When the extract was treated with serine protease inhibitors (PMSF, soybean trypsin inhibitor, or α‐2‐macroglobulin), nuclear swelling occurred; however, DNA synthesis was blocked. These data suggest that phosphoproteins are involved in one or more of the activation events and that a serine protease(s) is involved in the synthesis of DNA.
Seasonal changes in the effects of arginine vasotocin and stretch on Anolis uterine contractions in vitro
Authors: Jones Richard E. , Lopez Kristin H. , Summers Cliff H. , Austin Harriet B.
Published: June 2005

We determined the effects of acute stretch on spontaneous and arginine vasotocin (AVT)‐driven contractions of the Anolis carolinensis uterus in vitro. Whole uteri from reproductively inactive females (October) were placed in a bath of oxygenated 32°C Anolis “Ringer's.” Two initial tensions were utilized, 1.5 g or 15 g, the latter being an estimate of the tension on the wall of a uterine compartment. Uteri were then exposed to either saline or AVT (50 ng/ml), and spontaneous or AVT‐driven contractions were recorded for 20 min with the use of a strain gauge and physiograph. A similar experiment was performed on uteri from reproductively active females in the summer (June).

Our results indicate that the effects of acute stretch and AVT on uterine contractility were qualitatively similar in summer and fall. That is, 1) AVT induced a tonic contraction; 2) stretch decreased the duration of the tonic contraction; 3) the saline‐treated uteri exhibited spontaneous rhythmic contractions; 4) AVT increased the amplitude of the rhythmic contractions, but only at the lower tension; 5) there were no effects of AVT on the timing (contraction interval, duration, rest interval) of the rhythmic contractions; and 6) stretch increased the frequency of the rhythmic contractions. Season greatly influenced the magnitude of these contractile phenomena. Uteri tested during the breeding season exhibited greater distensibility, an increase in the amplitude and duration of the AVT‐driven tonic contraction, and an increase in the frequency of both spontaneous and AVT‐driven rhythmic contractions because of a decrease in both contraction duration and rest interval. Possible causes of these seasonal changes, as well as the relevancy of the stretch effects to the biology of the uterine egg compartment, are discussed.
Organ blood flow and brown adipose tissue oxygen consumption during noradrenaline‐induced nonshivering thermogenesis in the djungarian hamster
Authors: Puchalski Wolfgang , Böckler Heinz , Heldmaier Gerhard , Langefeld Martin
Published: June 2005

During NA‐induced NST blood flow through BAT increased from 0.18 ml min−1 to 3.21 ml min−1 in 23 °C acclimated (equals thermoneutrality) and from 0.61 ml min−1 to 9.67 ml min−1 in outdoors (−2 to 12°C Ta) acclimated Djungarian hamsters. In 23 °C acclimated hamsters this increase was accomplished by a diversion of blood flow from visceral organs without a change in cardiac output (19.7 versus 20.5 ml min−1 before and after NA). In outdoors acclimated hamsters we also observed a redistribution of blood flow from the viscera to BAT. In addition, cardiac output increased from 24.3 to 38.8 ml min−1. Metabolic rate of BAT in situ was determined from organ blood flow and the (A‐V)O2 of blood across the interscapular BAT. BAT of outdoor acclimated hamsters showed a significantly higher metabolism in comparison to 23 °C acclimated hamsters (81.1 versus 30.4 mlO2h−1). Furthermore, this calculation revealed that 28% (23 °C acclimated hamsters) and 61% (outdoors acclimated hamsters) of total NST were located in BAT of Phodopus sungorus.
Protein kinase C as a possible mediator of goldfish (Carassius auratus) ovulation
Authors: Ranjan Mukul , Goetz Frederick W.
Published: June 2005

The possible involvement of protein kinase C in goldfish Carassius auratus) ovulation was investigated. In vitro ovulation of oocytes that had undergone germinal vesicle breakdown and follicular wall detachment in vivo was observed with both a phorbol ester, phorbol‐12‐myristate‐13‐acetate, and a calcium ionophore, A23187. A combination of these two factors exhibited classic synergism and induced ovulation at much lower concentrations. Since protein kinase C is physiologically activated by diacylglycerols, three sn‐1,2‐diacylglycerols were also tested in combination with A23187. Of these, sn‐1‐oleoyl‐2‐acetylglycerol was ineffective, while sn‐1,2‐dioctanoylglycerol (diC8 and sn‐1,2‐dihexanoylglycerol (diC6) were found to synergize with the calcium ionophore even at the lowest levels tested. diC8 was more effective than diC6 at comparable levels. In vitro ovulation stimulated with phorbol ester and ionophore could be blocked with nordihydroguaiaretic acid at 10 μg/ml, while indomethacin at similar or higher (20 μg/ml) levels was ineffective. This suggests the involvement of lipoxygenase products in conjunction with protein kinase C activation during ovulation in this species. While a direct participation of protein kinase C and its mechanism of action remain to be demonstrated, these results indicate its involvement in the control of ovulation in goldfish.
Myoblast differentiation is induced by nerve transplanted to chick embryo legs
Authors: Bonner Philip H.
Published: June 2005

Chick embryos were denervated early in development in order to disrupt the normal inductive interactions between the nervous system and developing populations of mononucleated myoblasts and their precursors in the leg. Neural tissue, either spinal cord or ciliary ganglion, was transplanted to one leg of the denervated embryos; the other leg remained aneural. Clonal analysis of cell populations in the transplant‐containing legs showed that ectopic nerve tissue can recapitulate some of the neuromuscular interactions that occur in normally developing embryos. Chief among these was the observation that transplantation induced the appearance of the CMR‐III myoblast class in the leg muscle. Since the process by which CMR‐III myoblasts are produced from a precursor is dependent on nerve both in vivo and in vitro (Bonner, P.H. and T.R. Adams, Dev. Biol., 90:175–184, 1982), it was concluded that transplanted nerve tissue can also induce myoblast differentiation.
Female heterogamety in the swordtail, Xiphophorus alvarezi rosen (Pisces, Poeciliidae), with comments on a natural polymorphism affecting sword coloration
Authors: Kallman Klaus D. , Bao Isaac Y.
Published: June 2005

The sex‐determining mechanism of swordtails (Xiphophorus, Poeciliidae, Pisces) is poorly understood, because many laboratory strains of these species are characterized by biased sex ratios in either the male or female direction. Because of these ratios sex determination is said to be controlled by numerous male and female factors scattered over many chromosomes. However, direct experimental evidence for the polygenic theory is absent. Three strains of X. alvarezi were derived from natural populations in Guatemala, two of which (Dolores, Candelaria) always exhibit a ratio of 1:1, whereas the third one (San Ramón) shows a preponderance of males. Males of X. alvarezi, like those of other species of swordtails, develop a caudal appendage or sword at maturity. Chromatophores with carotenoid pigment (orange) are present in the sword of Dolores males and pigment cells containing sepiapterin (green) are present in the swords of males and the other two stocks. F1 and backcross hybrids were produced between the Dolores and Candelaria stocks. The sex ratios of all hybrid pedigrees was always in statistical agreement with unity. The pattern of inheritance of the two pigmentary traits demonstrated sex‐linkage, with female heterogamety (WY ♀ ♀ ‐ YY ♂ ♂).
Morphogenetic factors in hydroids: I. Stolon tip activation and inhibition
Authors: Müller Werner A. , Hauch Alexander , Plickert Günter
Published: June 2005

Colonial hydroids expand by means of vascular tubings, termed stolons, which elongate, generate new polyps, and branch at regular intervals. The pattern of the resulting network is controlled by specialized distal organs, the stolon tips. Two factors are described which activate or inhibit, respectively, stolon tip formation. Both factors emanate from existing tips. The activating factor is released into the medium and stimulates, in adjacent stolons, lateral tip formation and, hence, branching. A transplanted tip not only induces tip formation over distances of up to 140 μm but also attracts the induced tip by guiding the direction of its movement. Upon contact both tips fuse, provided the encounter occurs between isogeneic or histocompatible stolons, and an anastomosis is formed. The inhibitory principle appears to be transmitted within the stolon and is used to control branching distances. However, measurable traces of inhibitory activity leak into the medium. The factor is of low molecular weight. The activating and the inhibiting factors are both found in two distantly related colonial species—Hydractinia echinata (Athecata) and Eirene viridula (Thecata).
Retrovirus‐like particles in embryonic kidney tissue of the platyfish, Xiphophorus maculatus
Authors: Perlmutter Alfred , Potter Hugh
Published: June 2005

Ultrastructural studies were performed on embryos of an inbred strain (163A) of the platyfish Xiphophorus maculatus, and a pooled stock of the Rio Sarabia strain of the swordtail, X. helleri. Viral‐like particles were found in the kidney tissue of platyfish embryos. Exposure of pregnant platyfish to 5‐bromodeoxyuridine during the time of differentiation of embryonic melanocytes enhanced the production of viral‐like particles in platyfish embryos. Viral‐like particles were not found in untreated or drug‐treated swordtail embryos. The morphology of these particles corresponds to type C retroviruses.
Response of male brown bullhead catfish, Ictalurus nebulosus lesueur, to gonadotropin‐releasing hormone and gonadotropin
Authors: Rosenblum Paul M. , Callard Ian P.
Published: June 2005

These studies were performed in order to investigate the roles of GnRH and GtH in the regulation of reproductive function in male brown bullhead catfish, Ictalurus nebulosus. Adult catfish were given intravenous injections of salmon GtH (SG‐G100) or salmon GnRH (sGnRH), and plasma testosterone, 11‐ketotestosterone, and estradiol‐17β levels were measured. SGG100 elicited parallel increases in testosterone and 11‐ketotestosterone, with peak levels between 8–12 hr after treatment. The effects of SG‐G100 on plasma testosterone were dose‐dependent, whereas increased 11‐ketotestosterone was only seen with the two highest doses. Treatment with sGnRH elicited increased testosterone at 4 hr, and 11‐ketotestosterone between 4–24 hr posttreatment. No clear dose‐response to sGnRH was observed. The effects of SG‐G100 and sGnRH varied with the annual reproductive cycle. During early testicular recrudescence in May, both the pituitary and testis were sensitive to trophic stimulation, with 2‐ to 4‐fold increases in plasma androgens following sGnRH and SG‐G100. Neither treatment was effective in mature animals trapped in July. In November, despite low basal androgen levels, SG‐G100 and sGnRH elicited 2‐fold increases in plasma androgen levels. The stimulatory effects of sGnRH, but not SG‐G100, were abolished in hypophysectomized fish. These results indicate a functional hypothalamic‐pituitary‐testicular axis in this species, the components of which vary in sensitivity during the annual reproductive cycle in a manner consistent with the observed cycle of plasma steroids of this species.
Mechanical properties of mineralized and sclerotized puparial cuticles of the flies Musca autumnalis and M. domestica
Authors: Grodowitz Michael J. , Roseland Craig R. , Hu Kuo Kuang , Broce Alberto B. , Kramer Karl J.
Published: June 2005

Mechanical properties of mineralized and sclerotized puparial cuticles of the face fly, Musca autumnalis, and the house fly, M. domestica, respectively, were determined. The thickness of mineralized cuticle is 55% greater than that of sclerotized cuticle (thickness = 41.7 and 26.8 μm, respectively) from puparia of similar diameter (2.4 to 2.8 mm). Nonetheless, breaking forces for both types of puparial cuticle are similar (load ultimate strength = 9.3–10.9 g). However, the mineralized puparia are considerably stiffer than sclerotized puparia (elastic modulus = 346.4 kg mm−1 and 711.5 kg mm−1, respectively) and exhibit fracture at relatively lower load values (percentage total deformation at fracture = 3.5% and 11.0%, respectively). Differences in mechanical properties of puparial cuticle are probably due to the kinds and quantities of cuticular components: The mineralized puparia contain appreciably more inorganic components such as calcium, phosphorus and magnesium, while the sclerotized puparia consist of relatively more organic components such as proteins and phenolics. The evolutionary and functional significance of mineralization and sclerotization as mechanisms for puparial cuticle stabilization is discussed.
Monohydroxyeicosatetraenoic acid and leukotriene production by the inflammatory cells of Xenopus laevis
Authors: Green Floyd A. , Herman Ceil A. , Herman R. Peter , Claesson Hans‐Erik , Hamberg Mats
Published: June 2005

Ten frogs (Xenopus laevis) were injected with mixed bacteria to produce a septic peritonitis. Peritoneal inflammatory cells of eight animals were studied for monohydroxyeicosanoid and leukotriene production from exogenous arachidonic acid. Large amounts of 12‐hydroxyeicosatetraenoic acid were produced; smaller amounts of 5‐ and 15‐hydroxyeicosatetraenoic and leukotriene B4 were produced. Identifications were confirmed by retention times on HPLC, ultraviolet spectroscopy on all products, and gas chromatograph/mass spectrometry in the case of 12‐hydroxyeicosatetraenoic acid.
Influence of chromatographic fractions of extracts derived from bovine neural retina on newt (Notophthalmus viridescens) lens regeneration in vitro
Authors: Connelly Thomas G. , Green M. Sean
Published: June 2005

Removal of the ocular lens in adult newts (Notophthalmus viridescens) is followed by a series of cellular events leading to regeneration of a new lens by cell type conversion of pigmented iris epithelial cells at the dorsal pupillary margin (Yamada, Curr. Top. Dev. Biol. 2:247–283, 1967). Following depigmentation and five to seven cell divisions, iris epithelial cells redifferentiate into lens fiber cells and synthesize crystallin proteins (Yamada, Curr. Top. Dev. Biol. 2:247–283, 1967). This process is dependent upon neural retina in vivo (Stone, Anat. Rec. 131:151–172, 1958; Reyer, Dev. Biol. 14:214–225, 1966) and in vitro (Yamada et al., Differentiation 1:65–82, 1973). Acting on the hypothesis that the role of the neural retina is to promote passage of iris epithelial cells through the requisite number of cell cycles which will then allow them to redifferentiate as lens fiber cells (Yamada, in: Cell Biology of the Eye. Academic Press, New York, 1982), we undertook testing of the effects of eye‐derived mitogenic substances, as well as other mitogens, on regeneration of lens from iris in organ culture. We have previously defined a critical period for the retinal influence in vivo and in vitro, and have shown that crude extracts of retina can enhance regeneration of lenses in culture (Connelly et al., J. Exp. Zool., 240:343–351, 1986). In this paper, we report on the lens regeneration enhancing activity (LRA) of more highly purified fractions of the retinal extracts. Heparin‐sepharose chromatography of the crude retinal extract yields three fractions (Courty et al., Biochemie 67:265–269, 1985) called EDGF I, II, and III. EDGF I and II have affinity for heparin, while EDGF III does not. In our bioassay, LRA appears only in the EDGF III fraction. Dialysis of EDGF III against 0.1 N acetic acid yields a fraction which has affinity for cibacron blue sepharose (eluting at 2.15 M salt) and also has significant LRA. Because insulin at high doses has a marginal effect on lens regeneration in culture (Williams and McGlinn, Am. Zool. 19:923, 1979; Connelly, Differentiation 16:85–91, 1980), we tested IGF‐I. Because of the putative neurotrophic effects of transferrin (Tf) (Mescher and Munaim, J. Exp. Zool., 230:485–490, 1986), we tested Tf for its ability to enhance regeneration of the lens in culture. IGF‐I seems to have an enhancing effect on lens regeneration; Tf does not.
Rates of male pronuclear enlargement in sea urchin zygotes
Authors: Luttmer Shirley J. , Longo Frank J.
Published: June 2005

Rates of male pronuclear enlargement were determined using synchronous populations of fertilized sea urchin eggs (Arbacia punctulata and Lytechinus variegatus), fixed at regular intervals following insemination and stained with Hoechst 33342. The rate of male pronuclear expansion in both Arbacia and Lytechinus zygotes was linear and significantly affected by polyspermy, temperature, metabolic inhibitors (dinitrophenol, potassium cyanide, sodium azide, antimycin A, and oligomycin), and blockage of cytoplasmic alkalinization. Inhibitors of protein synthesis (emetine and puromycin) and disrupters of cytoskeletal elements (colchicine, nocodazole and cytochalasin B) had no effect on the rate of male pronuclear enlargement.
Light and electron microscopic observations of sperm entry in the chum salmon egg
Authors: Kobayashi Wataru , Yamamoto Tadashi S.
Published: June 2005

Sperm entry into the egg of the chum salmon, Oncorhynchus keta, was observed in living material as well as by electron microscopy. When the egg was inseminated in tap water, actively moving spermatozoa entered the micropylar canal and filled its lumen. When a narrow perivitelline space appeared in the egg (about 150 seconds after insemination), supernumerary spermatozoa were invariably discharged from the canal lumen. A similar discharge was observed in a few batches of eggs that were inseminated in Salmon‐Ringer solution. In response to the penetration of a fertilizing spermatozoon into the ooplasm, a narrow perivitelline space was formed in a restricted area of the animal pole. We suggest that the discharge is induced by the spouting of perivitelline material through the micropylar canal.

A fertilizing spermatozoon was observed in contact with the apex of the ooplasmic papilla in the micropylar canal and was seen to enter the ooplasm. When a fertilizing spermatozoon entered the egg, contractile activity was seen in the ooplasm, and a “protrusion” at the animal pole was formed. The papilla extending from the upper surface of the “protrusion” increased in length. These changes did not occur in unfertilized eggs stimulated by tap water in the absence of participation by the spermatozoon. It is, therefore, clear that the “protrusion” and the elongated papilla are analogous to the fertilization cone of invertebrate eggs.

The presence of the fertilization cone delayed the separation of the egg envelope from the ooplasm at the animal pole of the egg and inhibited penetration of any supernumerary spermatozoa into the perivitelline space. When the fertilization cone disappeared from the animal pole, 300 seconds after insemination, the micropylar canal decreased in diameter near the lower end. Super‐numerary spermatozoa were, thus, unable to pass through the thick egg envelope. Meanwhile, a transparent structure was seen to form at the micropylar vestibule and to serve as a barrier to entry by spermatozoa into the micropylar canal. We conclude that the formation of the fertilization cone and the spouting of perivitelline material through the micropylar canal play an important role in the prevention of polyspermy of the chum salmon egg.
ATP and the contractile vacuole in Amoeba proteus: Mechanism of action of exogenous ATP and related nucleotides
Authors: Pothier F. , Forget J. , Sullivan R. , Couillard P.
Published: June 2005

The mode of action of external ATP on the contractile vacuole of Amoeba proteus has been examined. ATP and, to a lesser extent, some other polyphosphates, interact with calcium at nonhydrolyzing membrane sites. This induces an increase of output of the contractile vacuole provided sodium is present in the medium. A long‐lasting reversible membrane depolarization occurs in the presence of ATP. Results are discussed in the light of theories describing the contractile vacuole as the principal sodium‐excreting organelle in freshwater Protozoa.
Characterization of enzymes that degrade crab exoskeleton: I. Two alkaline cysteine proteinase activities
Authors: O'brien Jack J. , Skinner Dorothy M.
Published: June 2005

Extracts from integumentary tissues of the Bermuda land crab, Gecarcinus lateralis, degraded proteins extracted from the membranous layer (ML), the innermost layer of the exoskeleton that serves as the interface between epidermal cells and calcified exoskeleton. Separation of the extracts by HPLC hydrophobic chromatography and characterization using 125I‐casein as substrate identified two peaks of degradative activity. The activities showed pH optima of 7 to 8, were sensitive to inhibitors of cysteine proteinases, and required the reducing agent, dithiothreitol, for activity, indicating that they are alkaline cysteine proteinases (ACPs). The pH optima of ACPs I and II indicated that they could function in the slightly alkaline extracellular environment of the proecdysial animal when the old exoskeleton is broken down. Although ACPs I and II are distinctly different from other crustacean cysteine proteinases (CP) they are similar to a CP activity present in extracts from the ML. A 23‐kDa protein from the ML was particularly susceptible to degradation by these enzymes. Activity of these enzymes in the extracellular environment might be controlled by the concentration of reducing agents as they are inactive unless in a reduced state.
Relation between interastral distance, time of furrow initiation, and rate of furrow progress in cylindrical sand dollar eggs
Authors: Rappaport R. , Rappaport Barbara N.
Published: June 2005

The purpose of this investigation was to determine whether measurable characteristics of furrow activity were affected when the distance between the asters was manipulated. The mitotic apparatus of cleaving Echinarachnius parma eggs was broken by passing the egg several times through a constricting pipet nozzle. Manipulated eggs were then confined in 80 μm i.d. silicone rubber capillaries. When the astral pairs developed before second cleavage, the distances between the pairs often differed. When the difference between interastral distances was 8.6 μm or less, furrows developed in the normal relation to both astral pairs within 1 minute in 31 of 35 cases. When the difference of interastral distances was greater than 8.6 μm, the furrow appeared first in association with the smaller distance in 53 of 54 cases. In all (24) cases in which the rates of progress of each astral pair were measured, the furrow formed between the closer astral pair progressed more rapidly when the distance was greater than 8.6 μm. No significant correlation between the rates of furrow progress and the magnitude of interastral distances measured 4 minutes before the beginning of furrowing could be demonstrated.
Serum immunoreactive insulin levels in intact and regenerating postmetamorphic xenopus laevis
Authors: Liversage Richard A. , Foty Ramsey A. , Miles Philip D. G.
Published: June 2005

In order to confirm the presence of immunoreactive insulin (IRI) in the serum of postmetamorphic Xenopus laevis, radioimmunoassay (RIA) methods were used. The concentration of hormone found in samples of blood serum taken from nonanaesthetized intact male and female animals by the guillotine method was 10.46 ± 0.76 μU/ml. Significantly higher IRI concentrations were found in our intact animals anaesthetized in MS 222 at pH 3.5 (21.9 μU/ml) compared with intact controls anaesthetized in MS 222 adjusted to pH 7.0, (14.4 μU/ml). During the wound‐healing stage subsequent to forelimb amputation in the experimental cases (0 hours to 3 days) anaesthetized in MS 222 pH 7.0, there were intervals of significantly elevated serum IRI followed by a period of decreased IRI concentration compared with the levels in anaesthetized (MS 222 pH 7.0) and nonanaesthetized intact controls. These fluctuations were due, presumably, to stress caused by amputational injury and/or anaesthetic. Serum IRI increased steadily from 3 to 14 days postamputation then remained stable for the balance of the regeneration period (28 days) compared with nonanesthetized intact controls. A positive correlation was found between immunoreactive insulin and glucose levels in the serum of our animals. However, no correlation exists between serum IRI levels and serum osmolality in the data.
The metabolic potential of hepatocytes and kidney tissue in the little skate, Raja erinacea
Authors: Mommsen Thomas P. , Moon Thomas W.
Published: June 2005

Isolated hepatocytes from the little skate (Raja erinacea) are characterized by a general low metabolic activity, which can be explained by the benthic lifestyle of the animal. Of the substrates tested, alanine, serine, and leucine are equally good oxidative substrates, and the highest rates of gluconeogenesis are achieved with alanine and glycerol as carbon sources. In both respects, lactate is a relatively poor substrate, and this probably reflects the low abundance of this potential energy source in the skate, even after bouts of anaerobic exercise. The long chain fatty acid oleate and glycerol are poor oxidative substrates for the hepatocytes, Experiments with 3‐mercaptopicolinate, an inhibitor for phosphoenolypyruvate carboxykinase (PEP CK), reveal that serine is funneled into gluconeogenesis through the serinetransaminase pathway, and PEP CK is bypassed. In vitro, the skate liver cells display the potential to synthesis and export ketone bodies from precursors sush as leucine or oleate, whereas added β‐hydroxybutyrate is poorly oxidized. The skate liver appears to be geared towards export of ketone podies while at the same time conserving glycerol carbon for lipid synthesis. Supplied with precursors such as bicarbonate, blutamine, and aspartate, the cells synthesize urea at a rate 0.85 μmol/g/hr at 10°C. β‐Hydroxybutyrate can acelerate the rate of urea synthesis, probably by increasing the intramitochondrial availability of ATP. Unlike any other vertebrate kidney, the tissue of the little skate appears to play no role in glucose synthesis. Skate kidney is characterized by an active oxidative metabolism and a broad substrate preference, with lactate, serine, alanine, and β‐hydroxybutyrate serving as equally good oxidative fuels.
Enzymes of intermediary metabolism in tissue of the little skate, Raja erinacea
Authors: Moon Thomas W. , Mommsen Thomas P.
Published: June 2005

Enzymes of intermediary metabolism were assayed in seven tissues (liver, kidney rectal gland, white muscle, red muscle, heart and brain) of the little skate, Raja erinacea, to assess the general metabolic desing of these tissues. Judged by the activities of enzymes linked to oxidative processes, the kidney, red and heart muscles, and rectal gland are the most metabolically active tissues, with ketone bodies potentially supplying the bulk of the required energy. The brain is only tissue with substantial potential to utilize exogenous glucose as an oxidative substrate; it also has the capacity to synthesize and degrade glycogen. The rectal gland may also use exogenous glucose, although its glycolytic potential is minor compared to that of other tissues. Amino acids, in addition to ketone bodies, may play significant metabolic role in these oxidative tissues based on the tissue activities of the amino transferases and the plasma content of amono acids. Enzyme activities in white skeletal muscle reflect the benthic, sluggish lifestyle of this species with low oxidative potential and rather limited anaerobic capacity. Hepatic tissue appears to be designed for the export of ketone bodies and to display a high potential for amino acid metbolism. The potential for gluconeogenesis, albeit at a low level, is realized only in the liver. Other pathways, especially fatty acid oxidation and pentose shunt, appear to play only monor roles in the intermediary metabolism of this elasmobranch.
Response of sipunculid hemerythrins to inorganic ions and CO2
Authors: Mangum C. P. , Burnett L. E.
Published: June 2005

The O2 equilibrium properties of sipunculid hemerythrins (Hr) are influenced by intracellular effectors. O2 affinity rises and cooperativity decreases when the tentacular O2 carrier is extracted into incorrect ratios of inorganic ions. The effectors include Ca2+ and Cl−, which raise the O2 affinity and lower cooperativity and which are present within the cell in either low levels or an inaccessible form. In the presence of salines approximating the inorganic ion conditions within the cell, tentacular hemerythrin‐O2 affinity decreases and cooperativity increases. Another effector of O2 bindng is CO2, which lowers O2 affinity and enhances cooperativity. While the inorganic ion and CO2 effects on coelomic hemerythrin are either absent or very small, the actions of at least the inorganic ions on tentacular Hr clearly have respiratory significance. Physiological variations in intracellular ions are very small, but the low levels of free Ca2+ and Cl− in the cell exaggerate the intrinsically lower O2 affinity of tentacular than coelomic Hr and thus enhance the routing of O2 from the ambient source to the tentacular compartment and from there to the coelomic compartment and then to metabolizing tissue.
Regulation of goby intestinal ion absorption by the calcium messenger system
Authors: Loretz Christopher A.
Published: June 2005

The role of the calcium messenger system in the regulation of ion absorption across the teleost intestine was studied using pharmacological intervention. Radiochloride transport was independent of external Ca2+ over the range 10 μM to 2.5 mM. Treatment with the Ca2+ ionophore A23187 (to elevate intracellular Ca2+) reduced Cl− absorption and produced hyperpolarization of the apical membrane potential of intestinal epithelial cells. The Ca2+‐calmodulin antagonists trifluoperazine (TFP) and calmidazolium (R24571) produced opposite effects, i.e., stimulation of Cl− absorption and cellular depolarization. Treatment with TFP or R24571 will block or override the inhibitory action of A23187. These data suggest a regulatory role for Ca2+ in the control of intestinal NaCl absorption and mediation via calmodulin.
Induction of deer antlers by transplanted periosteum: II. Regional competence for velvet transformation in ectopic skin
Authors: Goss Richard J.
Published: June 2005

The fallow deer develops its first set of antlers at about 1 year of age, but by 6 months the pedicles can be felt protruding from the frontal bones. If the thickened periosteum covering these locations is transplanted beneath the skin elsewhere on the body, it differentiates into a subcutaneous bony nodule which induces the overlying skin to transform into velvet as a small ectopic antler is produced. A survey of different graft sites has shown that skin on the fore and hind legs, hip, forehead, and outer and inner ears can participate in antler induction by undergoing velvet transformation. Tail, back, and nose skins fail to do so.
The lack of an effect of magnesium on the uptake of amino acids by the sea urchin Strongylocentrotus purpuratus
Authors: Bellis Susan , Davis James P. , Stephens Grover C.
Published: June 2005

The effects of magnesium on the influx, net entry, and efflux of amino acids by larvae of the sea urchin Strongylocentrotus purpuratus were investigated. Kinetic studies revealed that the influx of alanine is not dependent on external magnesium. In addition, influx and net entry are equivalent, as determined by high performance liquid chromatography (HPLC), and are independent of ambient magnesium concentrations.
Effects of eyestalk ablation upon water relations in the American lobster, Homarus americanus
Authors: Jackson Susan A. , Bruce Marilyn J. , Chang Ernest S. , Clegg James S.
Published: June 2005

A study of tissue and cell water content was carried out on eyestalk‐ablated (EA) and intact control juvenile lobsters (Homarus americanus). Both parameters were significantly higher in abdominal muscle and hepatopancreas from EA lobsters compared to controls. Similarly, the extracellular spaces of these tissues were larger in EA animals as were estimates of total hemolymph volume. The density and dry solids content of hemolymph from EA lobsters were less than controls, although hemolymph osmotic pressures of both groups were indistinguishable. The results are discussed in relation to other relevant studies on the effects of eyestalk ablation. Possible osmoregulatory and endocrine consequences are also considered.
Sex‐change linked growth acceleration in a coral‐reef fish, Thalassoma duperrey
Authors: Ross Robert M.
Published: June 2005

Environmental factors are known to affect the growth rates of fishes through most of their adult life. In the hermaphroditic saddleback wrasse (Thalassoma duperrey), the effects of social factors on growth were studied experimentally by subjecting individuals in submerged enclosures to various social environments that induce sex change. The results showed that social factors may either stimulate or inhibit the growth of adult fish. Individuals with one or more pen mates grew better than isolated individuals. Conspecifics stimulated more growth than heterospecifics. In paired fish, larger individuals inhibited the growth of smaller individuals. Growth rates were independent of both the sex and color phase of associates. Placing a tactile barrier between fish did not alter growth rates, but a tactile—visual barrier did. Increasing the space available to a fish did not increase the growth rate. Dominance relationships based on relative size and visual stimuli best explain the results obtained. Since all fish that showed growth acceleration also changed sex, a unitary, hypothalamically mediated, causal system is suggested. From an evolutionary perspective, sex‐change linked growth acceleration may reduce the cost of changing sex by shortening the nonreproductive interim in species in which males must be large to compete successfully for multiple matings.
Subcellular distribution of carbonic anhydrase activity in the gills of the blue crab, Callinectes sapidus
Authors: Henry Raymond P.
Published: June 2005

Differential centrifugation and density gradient ultracentrifugation were used to separate a basal–lateral membrane fraction from the cytoplasm in the gills of the blue crab, Callinectes sapidus. For both anterior and posterior gills of animals acclimated to 35 or 12 parts per thousand salinity the basal–lateral membrane fraction of the gill possessed significant levels of carbonic anhydrase activity. Membrane‐associated carbonic anhydrase (CA) activity was uniformly distributed between anterior and posterior gills, and it was only slightly sensitive to changes in salinity. This activity was not significantly altered by freeze‐thawing or sonication, but it was virtually eliminated after treatment with detergent. Stability of CA activity stored in vitro was not influenced by the presence of reducing agents. Protein‐specific CA activity in the membrane fraction was equal to or greater than that in the cytoplasmic fraction in all cases. Cytoplasmic CA activity in the posterior gills was highly sensitive to environmental salinity, increasing over 10‐fold. These data show that, in addition to a large cytoplasmic pool of CA activity, there is also a significant amount of CA activity associated with the basal–lateral membrane. The membrane associated CA is potentially available to catalyse the dehydration of hemolymph HCO3− to CO2 and thus facilitate CO2 excretion, while the role of cytoplasmic CA in ion regulation is confirmed.
Effects of stimulants of electrogenic ion transport on cyclic AMP and cyclic GMP levels in locust rectum
Authors: Chamberlin M. E. , Phillips J. E.
Published: June 2005

A variety of agents stimulate the chloride‐dependent short‐circuit current (Isc) across isolated locust recta. In this study, the role of cyclic nucleotides in mediating this stimulation was examined by measuring levels of cyclic AMP and cyclic GMP in tissues exposed to these agents. After bathing recta in saline, there is a decline in Isc, and this is accompanied by a fall in cellular levels of cyclic AMP and cyclic GMP. Stimulants of Isc across locust recta, corpus cardiacum (CC) extracts containing chloride transport‐stimulating hormone (CTSH) and forskolin, also elevate cellular levels of cyclic AMP. Between 5 and 10 min after addition of CC extract, there is an increase in cyclic AMP levels. During this same time period, the Isc rises at its maximal rate. The Isc remains elevated for at least another 20 min, even though tissue cyclic‐AMP levels decline rapidly by 15 min. These results suggest that stimulation of Isc is induced by a rise in cyclic AMP, but the cessation of stimulated active ion transport is controlled by other biochemical processes. In contrast to the relatively rapid rise in cyclic‐AMP levels, a 60‐min exposure to CC extract was required to elicit a rise in cyclic GMP, and therefore it may not be involved in the early stages of Isc stimulation.
Electrical responses to amputation of the eye in the mystery snail
Authors: Bever Michele Miller , Borgens Richard B.
Published: June 2005

Immediately following amputation through the eyestalk of the mystery snail (Pomacea), a persistent ionic current enters the apical amputation surface of the eyestalk stump. The circuit is completed by current driven from undamaged integument of the eyestalk stump and other body regions. The current is relatively steady during the first 10 hours following amputation. Currents subsequently begin a slow decline to base line levels by 60 hours postamputation—a time coincident with wound healing processes. The “battery” driving this ionic current is the internally negative transepidermal potential existing across the snail integument—perhaps the result of a net inward pumping of chloride across the skin. This system is compared to other regeneration models such as the amphibian limb, bone fracture repair, and skin wound healing. We suggest that ionic current may be a control of eye regeneration in the snail.
Comparison of heterospermic and homospermic inseminations as measures of male fertility
Authors: Robl J. M. , Dziuk P. J.
Published: June 2005

This study attempted to determine a basis for the previously observed greater sensitivity of heterospermic tests when compared to homospermic tests for detecting differences in fertility between males. In theory, the results of heterospermic tests are an indication of the proportion of eggs fertilized per unit time whereas results of homospermic inseminations measure only the cumulative or final proportion of eggs fertilized. The fertilizing ability of sperm from males of CF1 and C57BL/6N strains of mice was compared homospermically using both relatively high and low concentrations of sperm and by measuring the proportion of eggs penetrated per unit of time. The fertilizing ability of sperm from these strains was also compared using heterospermic inseminations. When females were inseminated with a high concentration of sperm, males of both strains fertilized a high and indistinguishable percentage of eggs when examined after 30 hr. When females were inseminated with either a low concentration of sperm or when the proportion of eggs penetrated was measured at 5 hr, differences between strains of mice were distinguishable. Heterospermic insemination further magnified the observed difference between strains. The results of this study confirm that measuring the percentage of eggs fertilized per unit of time can enhance the magnitude of differences between males in fertility as compared to measuring only the final percentage of eggs fertilized. Measuring the percentage of eggs fertilized per unit of time does not, however, entirely account for the large differences observed between fertility of males when they are compared using heterospermic inseminations.
Directional cell movement during early development of the teleost Blennius pholis: I. Formation of epithelial cell clusters and their pattern and mechanism of movement
Authors: Trinkaus J. P.
Published: June 2005

Embryos of the teleost Blennius pholis provide exceptional material for observation of the formation and movement of cell clusters in vivo because the clusters are packed with melano‐somes and migrate beneath the transparent enveloping layer. These clusters arise from two pigmented cell masses (PCM) which appear precociously on either side of the embryonic axis at 3/5 epiboly, at the future level of somites 1 and 2. As development proceeds, each PCM enlarges and spreads on its lateral margins to form an epithelial sheet. As spreading continues, the sheet fragments, forming small cell clusters that move in a distad direction in the yolk sac. The highly motile lateral marginal cells of the spreading PCM, as well as those of the marginal cells of each moving cluster, invariably protrude highly flattened lamellipodia, which terminate in long, fine, often branched filopodia. As cell clusters leave the PCM, they form long, taut retraction fibers. The rate of spreading of both the lateral edge of the PCM and the initial phase of cluster movement, is higher (1.0 μm/min or greater) than the later rate of cluster movement, apparently because at this phase, motile activity is confined to the distal borders of each. This directional migration ceases in 24 h at 16°–18°C, when the farthest clusters have reached the ventral region of the yolk sac. By then, all clusters are spaced more or less evenly, apparently due to cessation of all cluster movement at about the same time. Once movement ceases, the clusters remain immobile for 2–4 days, depending on the temperature.