bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of sea cucumber oocyte maturation by starfish radial nerve extracts
Authors: Maruyama Yoshihiko K.
Published: June 2005

Cross‐reactivity of maturation‐inducing factors was studied between sea cucumbers and starfish. Radial nerve extracts from both sea cucumbers and starfish induce maturation in ovarian oocytes associated with follicle cells but not in follicle‐free oocytes. Radial nerve extracts of sea cucumbers did not induce maturation in ovarian oocytes or follicle‐free oocytes of starfish. In contrast, radial nerve extracts of starfish induce maturation of both ovarian oocytes and follicle‐free oocytes of sea cucumbers. Based on protease sensitivity and elution patterns on Sephadex G‐15 or G‐50 columns, the active factor from starfish radial nerve extracts appears to be peptides similar in molecular weight to starfish gonad‐stimulating substance (GSS). Additionally, 1‐MeAde, a non‐species‐specific maturation‐inducing substance in starfishes, had no maturation‐inducing effects on sea cucumber oocytes. It was concluded that starfish radial nerve extracts contain a substance(s) which induces maturation of sea cucumber follicle‐free oocytes, and sea cucumber oocytes maturation is regulated by substances different from those in starfish.
Morphogenetic movements and a provisional fate map of development in the holostean fish Amia calva
Authors: Ballard William W.
Published: June 2005

Cell‐marking experiments using the vital dye Nile blue sulfate have shown that in embryos of the holostean fish Amia calva the first cleavage plane is normally the plane of bilateral symmetry, that no significant “in‐turning” of presumptive mesoderm occurs at the germ ring or terminal node, and that cells destined for the heart, head mesoderm, and foregut derivatives (adhesive organs and pharynx) are located near the animal pole already in late cleavage stages, rather than brought there by morphogenetic movements.

As in teleosts, cells destined for the central nervous system (CNS), the first few somites, and also the kidneys and their longitudinal ducts are put in place directly by convergence of subsurface cells from less than the dorsal half of the blastoderm through the embryonic shield. While this is being completed the rest of the somite mesoderm is delivered to the body axis by convergence along the germ ring, which it has reached by earlier obliquely epibolic movements of internal cells.

The outermost epithelium of the embryo moves chiefly by epibolic stretching and does not contribute significantly to any internal organ. Dye marks placed upon external cells of the rim of the germ ring or the terminal node remain there throughout epiboly, and those placed anterior to either the rim or the node fail to reach these. When dye carriers are placed upon the outer epithelium their dye is not only held within its cells, but by diffusion it is also brought to deeper cells that are destined for mesodermal and nervous structures. The convergent movements of these deeper cells tend to disengage them from the stained epithelium that originally covered them.

The hindgut is apparently formed by the posterior hypoblast, a few cells of which may from time to time be seen from the outside of the embryo, protruding beyond some sector or other of the germ ring epiblast. The trunk‐tail bud is assembled as in teleosts by extension of the CNS, the notochord, the hindgut, and the primitive kidney ducts from the embryonic shield and also by the convergence of internal cells along the germ ring and from the mesodermal areola that is left by its closure.

Rough charts of the morphogenetic movements before the major phase of differentiation and a first approximation of a fate map for Amia are presented. There is a discussion of the similarities and differences of these in comparison with those of teleosts and amphibia.
Characterization of the secretory proteins of rat preputial gland in relation to urinary proteins
Authors: Langeland Astrid
Published: June 2005

The water‐soluble proteins of the rat preputial gland secretion were characterized in native and SDS‐treated form on polyacrylamide gel electrophoresis. Nine major proteins were present in the secretion. One protein was a glycoprotein of molecular weight greater than 200,000 with β‐glucuronidase activity, and the other eight proteins had a molecular weight of 17,000, but with different charges. Acid phosphatase and arylsulphatase activities were present in the secretion in minor amounts. The isoelectric points of the secretory proteins ranged from 8.5 to 5.3; none of the proteins were lipoproteins, and there were no sex differences. The male and female rat urinary proteins were also characterized electrophoretically. The male rats had two different protein patterns, probably genetically determined. The female rats showed basically one urinary protein pattern, but their urines were frequently mixed with the preputial gland secretory proteins, which most likely played a part in the chemical communication. The mixing could not be correlated to daytime or estrous cycle.
Gill ammonia transport
Authors: Evans David H. , Cameron James N.
Published: June 2005

Ammonia theoretically can traverse the gill epithelium of aquatic animals in a variety of ways. Recent experiments utilizing both whole animals (fish and arthropods), and perfused heads of fishes indicate that diffusional movement of both NH3 and NH4+ takes place, as well as basolateral (serosal) Na+/NH4+ exchange. Data supporting the presence of apical (mucosal) Na+/NH4+ exchange are more equivocal, and there is no published evidence for transport via basolateral NH4Cl + NaCl co‐transport. The relative roles of various pathways may depend upon the species and its salinity of acclimation.
Immunocytochemical demonstration of steroid hormones in the granulosa cells of the medaka, Oryzias latipes
Authors: Onitake Kazuo , Iwamatsu Takashi
Published: June 2005

Immunocytochemical identification of steroid hormones was performed in granulosa cells isolated from large ovarian follicles of the medaka. The granulosa cells recovered from daily spawning females, 8.5 h after the onset of light, reacted with anti‐progesterone and anti‐17α‐hydroxyprogesterone antibody, while the granulosa cells treated 2.5 h after the onset of light did not. After 6 h stimulation with gonadotropin (PMS) in vitro, the isolated granulosa cells reacted with anti‐progesterone antibody. The granulosa cells examined 8.5 h after the onset of light did not react with anti‐estradiol or antiestriol antibody.

These results demonstrate that, in Oryzias latipes, progestins (progesterone and 17α‐hydroxyprogesterone) are synthesized in the granulosa cells which are directly stimulated by gonadotropin.
Characterization of macrophages in the tail of the anuran tadpole
Authors: Nishikawa Akio , Yoshizato Katsutoshi
Published: June 2005

Macrophage‐like cells in the tail mesenchyme of bullfrog tadpoles were isolated and characterized. These cells actively ingested latex beads into their perinuclear cytoplasm and thyroid hormone was essential for their survival in vitro. The requirement for this hormone is a unique property of these cells since other types of tail cells, such as epidermal cells and mesenchymal fibroblasts, are unable to survive in the presence of the hormone. The unusual characteristics of the cells suggest that they are indeed phagocytic macrophages and that they play a crucial role in the thyroid hormone‐dependent breakdown of the tail.
Membrane activity and its correlation with vacuolar contraction in the heliozoan Echinosphaerium
Authors: Nishi Takako , Kobayashi Makoto , Shigenaka Yoshinobu
Published: June 2005

Membrane potentials were recorded from two species of Heliozoa, Echinosphaerium akamae and E. nucleofilum. The resting potential ranged from −20 to −50 mV with an average value of −33.7 ± 12.9 mV (± SD, n = 10) and −31.6 ± 9.5 mV (± SD, n = 10) in E. akamae and E. nucleofilum, respectively. Action potentials were elicited spontaneously or in response to applied current. They were abolished in Ca2+ ‐deficient solution with no effect by Na+ or Mg2+, indicating Ca‐spikes. Membrane hyperpolarization, which correlated with the contraction of contractile vacuole (H‐CV), was recorded. The onset of hyperpolarization appeared to be simultaneous with the initiation of contraction. The amplitude of H‐CV was dependent on K+ ‐concentration in the external fluid with reduction by increasing K+. The results suggested that H‐CV was caused mainly by the increase in K+ ‐conductance of the membrane with a contribution in part by Cl−.
Neuromuscular properties in serially homologous lobster limbs
Authors: Mearow K. M. , Govind C. K.
Published: June 2005

The lobster Homarus americanus has five pairs of serially homologous thoracic limbs, the most anterior being the paired chelae followed by four pairs of walking limbs (WLs). We have examined the opener and closer muscles of the WLs in terms of their fiber composition, axonal branching pattern, and synaptic properties. The opener muscle is similar in these serially homologous limbs being composed of all slow fibers. The closer muscle, however, differs in fiber composition amongst the limbs. In the small, nonchelate 3rd and 4th WL, it consists of only slow fibers, while in the much larger, chelate 1st and 2nd WL it has 40% fast and 60% slow fibers. In the chelae, which are bilaterally asymmetric, the closer muscle is known to consist of 70% fast and 30% slow fibers in the cutter chela and all slow fibers in the crusher chela. These differences in the closer muscle reflect differences in the function of the thoracic limbs. Differentiation in the serially homologous limbs occurs to a lesser extent in the pattern of axonal branching and excitatory innervation. Thus bifurcation of the motor axons into two primary branches each supplying one‐half of the bipinnate muscle is found in the anterior limbs but tends to disappear in the most posterior limb. Fast axon synapses are more prevalent in the closer muscle of the 1st WL than in the 4th WL. Such differences in distribution between 1st and 4th WLs are also found for the single excitor axon synapses to the opener muscle.
Distribution of interstitial retinol‐binding protein (IRBP) in the vertebrates
Authors: Bridges C. D. B. , Liou G. I. , Alvarez R. A. , Landers R. A. , Landry Andre M. , Fong S.‐L.
Published: June 2005

Immunoblots of interphotoreceptor matrix preparations from 20 species belonging to six vertebrate classes were probed with antibodies against bovine interstitial retinol‐binding protein (b‐IRBP). Each preparation displayed an immunoreactive protein band. In the Osteichthyes, the apparent Mr of this band was 67,600 ± 2,700 (x̄ ± SD, n = 8). In two of the Osteichthyes, the band was resolved into a closely spaced doublet. Including previously published data for five mammals and one amphibian, species from the other classes (Chondrichthyes, one species; Amphibia, four species; Reptilia, one species; Aves, one species; Mammalia, nine species) had IRBPs with Mr that averaged 2.0 times that of the Osteichthyes, namely 134,200 ± 8,600 (x̄ ± SD, n = 17). Frog IRBP was very similar to mammalian IRBP in terms of its immunohistochemical distribution (determined with rabbit anti‐frog IRBP antibodies), its molecular weight (sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel‐filtration chromatography), retinol‐ and concanavalin A‐binding ability, and because it was synthesized and secreted in vitro by the isolated retina but not by the pigmented layers of eye. Goldfish IRBP apparently binds exogenous (3H)‐retinol but does not bind concanavalin A and has about half the Mr of frog IRBP. The occurrence of IRBP‐like proteins crossreacting with anti b‐IRBP antibodies in the interphotoreceptor matrix of all six major vertebrate classes is consistent with the hypothesis that IRBP is an important element in the vertebrate visual cycle.
Assisted fertilization by zona drilling: A mouse model for correction of oligospermia
Authors: Gordon Jon W. , Talansky Beth E.
Published: June 2005

A micromanipulation apparatus was used to produce holes in the zonae pellucidae of unfertilized mouse oocytes. A microneedle loaded with acid Tyrode's solution was brought into contact with the zona surface, and positive flow was used in conjunction with mechanical pressure to cause a localized dissolution of the zona. Treated eggs were then fertilized in vitro in comparison with control cells. The zona drilling procedure decreased the sperm count required to achieve fertilization by a factor of approximately 100. The rate of polyspermy in zona‐drilled oocytes was not greater than in controls, and oocytes fertilized after drilling, when implanted into pseudopregnant foster females, developed to term at the same rate as controls. The results demonstrate that zona drilling is a safe, effective method of increasing the efficiency of fertilization in vitro and may be useful both in agriculture and medicine for conferring fertility upon males with low sperm counts.
Assimilation and deposition of dietary fatty alcohols in Leach's storm petrel,Oceanodroma leucorhoa
Authors: Place Allen R. , Roby Daniel D.
Published: June 2005

The diet of Leach's storm petrel (Oceanodroma leucorhoa) chicks has a high lipid content (up to 60% of fresh mass), and, for certain populations, much of the dietary lipids are wax esters (up to 70% of total lipid). In order to determine the metabolic fate of dietary wax esters, we fed chicks [1‐14C]cetyl oleate in either a low wax (20%, w/w) or a high wax (80%, w/w) mixture of wax ester and triacylglycerols. Wax ester in the stomach remained unhydrolyzed for extended periods, with up to 38% of the label still unassimilated after 36 hr. Hydrolysis occured principally in the duodenum, where the fatty alcohol product was rapidly oxidized to fatty acid, apparently at the intestinal epithelia. Assimilated label was primarily metabolized and respired as carbon dioxide, with most of the remainder incorporated into triacylglycerols and deposited in storage fat depots. Hydrolysis of wax ester and assimilation of the fatty alcohol moiety were extremely efficient, with less than 0.2% of ingested label excreted. Assimilation efficiencies for label in low wax and high wax meals were statistically indistinguishable. Chicks fed 20% (w/w) [1‐14C]cetyl alcohol in triacylglycerols had similar assimilation efficiencies as those fed labeled wax ester, indicating that hydrolysis of the ester linkage does not limit wax ester assimilation. This study suggests that sea birds can possess an efficient means for metabolizing wax esters, an abundant energy source in the marine environment, which have previously been thought to be difficult to assimilate.
Neoplastic transformation in the planarian: II. Ultrastructure of malignant reticuloma
Authors: Hall Frederick , Morita Michio , Best Jay Boyd
Published: June 2005

Cadmium and phorbol ester induced tumorigenesis in the planarian, Dugesia dorotocephala, develops as a cocarcinogenic process involving initiation and promotion in the progression of neoplastic disease. Treatment of intact planarians with sublethal concentrations of cadmium sulfate and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) induced a type of infiltrating tumor that proved to be potentially lethal. Surgical transplantation of such tumorous tissues into otherwise healthy planarians resulted in the same histopathological progression to lethality, which confirmed the metastatic nature of the neoplasia. Electron microscopic studies revealed that both the chemically‐induced and the transplantation‐based tumors involved, exclusively, the proliferation and differentiation of abnormal reticular cells, referred to as reticuloma cells. Reticular cells normally are ameboid, phagocytic, and are thought to provide the planarian with a phylogenetic predecessor of an immune surveillance system. A considerable incidence of mitosis was observed within the tumor areas; and the sequence of differentiation, from transformed stem cells to mature but nonfunctional reticuloma cells, was elucidated. This profile of differentiation supports the concept of cellular derivation via stem cell dynamics as opposed to dedifferentiation. A variety of ultrastructural abnormalities were characterized: several of which tend to substantiate the anaplastic quality of the reticuloma, while others are more specifically diagnostic for malignancy. These findings further extend the potential usefulness of the planarian malignant reticuloma as a model system for the study of neoplastic stem cell diseases.
Differences between early‐ and late‐maturing genotypes of the platyfish (Xiphophorus maculatus) in the morphometry of their immunoreactive luteinizing hormone releasing hormone‐containing cells: A developmental study
Authors: Halpern‐Sebold Leslie R. , Schreibman Martin P. , Margolis‐Nunno Henrietta
Published: June 2005

Immunoreactive luteinizing hormone releasing hormone (ir‐LHRH) containing perikarya, brain nuclei, and pituitary cells were studied during the postnatal development of male sibling platyfish (Xiphophorus maculatus) genetically determined to reach puberty at two different ages using immunocytochemical, cytological, and morphometric methods. Ir‐LHRH‐containing perikarya first appear in the nucleus olfactoretinalis (NOR) at 5 weeks of age in early maturers and at 11 weeks in late maturers at a maximum number which is similar in both genotypes and remains constant into adulthood. The dimensions of the NOR and its perikarya increase up to the initiation of sexual maturation (gonopodial stage 2) in both genotypes. In the nucleus preopticus periventricularis (NPP), ir‐perikarya appear at stage 2 and are maximum in number at maturity (stage 6) when early maturers have 50% more than late maturers. Measurements for the NPP increase between 1 week and stage 6 in both genotypes. In the nucleus lateralis tuberis (NLT), irperikarya appear soon after stage 2 in early maturers but are never seen in late maturers. Late maturers also have fewer ir‐LHRH containing pituitary cells than early maturers. In both genotypes, measurements for the NLT increase to stage 2 and then decrease to stage 6.

During sexual development there are differences between early‐ and late‐maturing genotypes in the morphometry of their LHRH‐containing brain centers. The timing of sexual development creates significant differences in the cytological and cytometric characteristics of the three ir‐LHRH‐containing brain nuclei in fish of the same age but different genotype. Our results also show that for both genotypes there is a positive correlation between the total number of ir‐LHRH brain neurons and the total number of ir‐pituitary cells and both are lower for late maturers at every age and stage.
Integumentary uptake of acetate and propionate (VFA) by Tubifex sp., a freshwater oligochaete. I. Uptake rates and transport kinetics
Authors: Hipp Erich , Mustafa Tariq , Bickel Ursula , Hoffmann Klaus H.
Published: June 2005

The freshwater oligochaete Tubifex tubifex can achieve an uptake of short‐chain volatile fatty acids (VFA; acetate and propionate) from artificial tap water at naturally occurring interstitial concentrations of 5 to 1000 μM. The uptake results from a combination of saturable and nonsaturable transport, the former displaying Michaelis‐Menten‐type kinetics. The saturable component is susceptible to inhibition by structurally analogous substances. The kinetics of the inhibition were found to be competitive. VFA uptake rates are strongly depressed by potassium cyanide and iodoacetate. Furthermore, VFA uptake is susceptible to inhibition by ouabain and to Na+ depletion. Q10 values in excess of two are also consistent with the suggestion that a mediated system for VFA absorption exists in the integument of T. tubifex.
Loss of seawater preference in chum salmon (Oncorhynchus keta) fry retained in fresh water after migration season
Authors: Iwata Munehico , Ogura Hiroyuki , Komatsu Shichiko , Suzuki Keiji
Published: June 2005

Salinity preference of chum salmon fry (Oncorhynchus keta) was measured by the use of a preference tank. In April, when they normally migrate down to the sea, freshwater chum fry weighing about 0.6 g preferred seawater diluted 1:2 with fresh water (11 parts per thousand in salinity) and seawater over fresh water. Chum fry acclimated to the diluted seawater for 1 day preferred seawater over fresh water. In May, however, freshwater fry preferred only diluted seawater. Furthermore, the preference for seawater of freshwater fry, and of fry that had become acclimated to diluted seawater, decreased significantly. Plasma levels of sodium ions in freshwater fish were 138–142 mmol/L in April and May. When the fish were transfered to diluted seawater in April and May, the levels of sodium ions increased gradually over 6 hours to the level in seawater‐acclimated fish, namely 153–155 mmol/L. Plasma levels of sodium ions in fry acclimated to diluted seawater did not change after exposure to seawater. In freshwater fry that were exposed to seawater, the maximum concentration in plasma of sodium ions was 165 mmol/L in April and 177 mmol/L in May. The preference of fry acclimated to seawater or to diluted seawater was also examined in April and May. More than 70% of fry that had acclimated to seawater showed a preference for diluted seawater and no preference for fresh water was noted in either the fry acclimated to seawater or to diluted seawater. Thus, for chum fry, the preference for seawater, as well as their adaptability to seawater, is maximal in April, during the migration period. No preference for fresh water was observed at any stage.
Factors regulating carbohydrate and lipid metabolism isolated from the corpus cardiacum of the Eastern lubber grasshopper, Romalea microptera
Authors: Spring Jeffrey H. , Gäde Gerd
Published: June 2005

Romalea microptera corpus cardiacum (RCC) contains large quantities of peptide material that is capable of eliciting strong hyperlipemic (maximum increase, 26 mg/ml; locusts) and hypertrehalosemic (maximum increase, 27 mg/ml; cockroaches) responses in test species. Calculation indicate that RCC contain more than an order of magnitude more bioactive material than either Locusta or Periplaneta corpus cardiacum. R. microptera itself shows no response to injections of synthetic locust adipokinetic hormone I (AKH I) at doses of up to 100 pmol, although injection of RCC at high concentrations (up to 1.0 gland‐equivalents) causes moderate hyperlipemia (maximum increase, 3 mg/ml). Starved R. microptera do not exhibit the metabolic hyperlipemia observed in starved L. migratoria, but starvation does block the RCC‐stimulated hyperlipemia. Neither fed nor starved R. microptera show a hypertrehalosemic response to RCC or AKH I. Reversed‐phase high‐performance liquid chromatography (RP–HPLC) shows the adipokinetic/hypertrehalosemic bioactivity to be concentrated in two peaks, which are present in the ratio of 6:1 Peak I: Peak II. Further RP–HPLC studies suggest that Peak II is identical to the adipokinetic hormone from the cricket Gryllus bimaculatus, while Peak I appears to be a previously unknown neuropeptide.
Immunohistochemical study of calmodulin in developing mouse testis
Authors: Sano Mamoru , Ohshima Akiko‐Seto , Kawamura Noriko , Kitajima Satoko , Mizutani Akira
Published: June 2005

The purpose of this study was to determine the localization of calmodulin in the developing mouse testis by the indirect immunoperoxidase method. In addition, the amount of calmodulin in pachytene spermatocytes, spermatids, and residual bodies isolated from the mouse testis and epididymal spermatozoa was quantitated by the adenylate cyclase activation assay and by enzyme immunoassay. The relative levels of calmodulin in the developing mouse testis and in the isolated testicular germ cells were confirmed by western transfer staining. The level of immunoreactive calmodulin was very low in the testes from immature animals. In testes from the mature mouse, calmodulin was found to be localized in spermatocytes and spermatids, but was not found in spermatogonia, Sertoli cells, and interstitial cells. By contrast, immunochemical staining of tubulin was extremely intense in Sertoli cells. Biochemical determinations also showed that pachytene spermatocytes, round spermatids, spermatozoa, and residual bodies contained 14.9μg, 15.8μg, 2.3μg and 5.2μg of calmodulin per mg of protein, respectively. Both the immunochemical and the biochemical studies revealed that levels of calmodulin were high in the spermatocytes and in the round spermatids, as compared to the level in spermatozoa. This fact strongly suggests that the large amount of calmodulin in mammalian testes may be associated primarily with meiotic divisions and/or spermatogenesis.
Induction and inhibition of in vitro oocyte maturation and production of steroids in fish follicles by forskolin
Authors: Iwamatsu T. , Takahashi S. Y. , Sakai N. , Nagahama Y. , Onitake K.
Published: June 2005

The effects of forskolin (FK) on in vitro oocyte maturation and production of steroids were examined in Oryzias latipes. When oocytes within preovulatory follicles were preincubated in the presence of FK for 2–10 hr, they matured normally after additional incubation for 10–20 hr in plain culture medium. Naked (follicle cell‐free) oocytes did not mature under these conditions. FK stimulated dose‐dependent production of steroids (estradiol‐17β, E2, and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one, 17α,20β‐diOHprog) and cAMP in follicle (granulosa) cells. On the other hand, exposure to FK within 2 hr after 17α,20β‐diOH prog stimulation caused reversible inhibition of gonadotropin (PMS)‐ or 17α,20β‐diOH prog‐induced maturation of the intrafollicular oocytes in vitro. FK also significantly inhibited the 17α,20β‐diOHprog‐induced maturation of naked oocytes, suggesting the existence of adenylate cyclase in fish oocytes. These data indicate that in Oryzias latipes, FK induces oocyte maturation by stimulating follicular production of maturation‐inducing steroid (MIS), probably 17α,20β‐diOH prog, via an increase in cAMP, and that it may inhibit oocyte maturation by increasing ooplasmic cAMP and some inhibitory interaction between the granulosa cells and the oocyte through intercellular communication.
Active ureogenesis in a freshwater air‐breathing teleost, Heteropneustes fossilis
Authors: Saha N. , Ratha B. K.
Published: June 2005

Activities of all the enzymes of ornithine‐urea (o‐u) cycle and uricolytic pathway were assayed in different tissues of a freshwater air‐breathing teleost, Heteropneustes fossilis. High activity of all o‐u cycle enzymes as observed in the liver and kidney, were comparable to those of actively ureogenic fishes and amphibians. All the three enzymes of uricolytic pathway were found only in liver tissue. These observations strengthen an earlier suggestion made that active ureogenesis did exist in some freshwater teleosts such as H. fossilis. Presence of an active o‐u cycle in H. fossilis indicates that this fish is either relatively primitive to the purely aquatic freshwater teleosts retaining the ancestral character of a functional o‐u cycle or the genes for the synthesis of o‐u cycle enzymes might have been derepressed as a secondary modification for its adaptation to temporary dehydration or hyper‐ammonia environment.
Effects of catecholamines on early development of the chick embryo: Relationship to effects of calcium and cAMP
Authors: Sarasa Manuel , Climent Salvador
Published: June 2005

Catecholamines (dopamine or norepinephrine) injected under the blastoderm of the unincubated chick embryo produced a thickened primitive streak and prevented the migration of axial mesoblast after 24 h. The mesoblastic cells that accumulated in the primitive streak contained many intracytoplasmic yolk granules. After 48 h, neural tube, notochord, and somites were severely affected, and their cells appeared loaded with yolk inclusions. Heart, lateral plates, blood cells, and blood vessels differentiated normally. At the onset of gastrulation, the level of glycogen was fivefold lower in catecholamine‐treated embryos than in control embryos. Injection of glucose plus dopamine, at equimolar concentrations resulted in normal development both at 24 h and at 48 h. Because adrenegic stimulation of glycogenolysis in differentiated cells is usually mediated by cAMP and/or by calcium, we attempted to determine whether these substances could reproduce the effects of catecholamines. Only calcium was able to produce, to a limited extent, the same morphogenetic disturbances as those produced by catecholamines, whereas the chelating agent, ethylenediamine tetraacetic acid, when administered with dopamine, partially inhibited the effects of catecholamines. An increase in the number of yolk granules was the only common finding among embryos treated with cAMP and catecholamines. Blood and a well differentiated, gastrular endoderm always developed, independently of the nature of the substance with which the embryos had been treated. Morphogenetic disturbances caused by exogenous catecholamines could be due to depletion of glucose. Alternatively, a different metabolic commitment might exist within the diverse populations of cells that constitute the mesoblastic layer.
Hormonal regulation of myoblast proliferation and myotube production in vivo: Influence of prostaglandins
Authors: McLennan Ian S.
Published: June 2005

The study of myoblast proliferation and fusion to form myotubes in vivo has centered around the role of the innervating motoneurones. Hormonal factors such as prostaglandin E1 (PGE1) are important during in vitro myogenesis, but their role in vivo has yet to be elucidated. In vitro, PGE1 appears to switch myoblast from a mitotic to a fusion mode. Consistent with this hypothesis, administration of PGE1 to chicken embryos decreased the number of myonuclei incorporated into their muscles. The effect of inhibitors of prostaglandin synthesis (aspirin and indomethacin) on in vivo myogenesis was not, however, as expected. Both drugs decreased the number of myonuclei incorporated into the muscles of treated embryos, which is the opposite of what would have been expected if they were enabling myoblasts to undergo additional divisions by delaying their onset from the mitotic cycle. The simplest explanation of this observation is that the effect of aspirin and indomethacin is mediated by a prostaglandin other than E1, or by a systemic factor whose levels are regulated by a prostaglandin. The maximum extent of the reduction caused by PGE1 and the inhibitors of prostaglandin synthesis was only 25–30%, suggesting that only a subpopulation of myoblasts is effected by these drugs. The number of myotubes formed in the treated embryos closely paralleled the total number of myonuclei, indicating that the number of myoblasts fusing to form a myotube is constant even when the total number of available myoblasts is diminished.
Discrimination of male conspecific from male heterospecific odors by male scincid lizards (Eumeces laticeps)
Authors: Cooper William E. , Garstka William R.
Published: June 2005

Male broad‐headed skinks, Eumeces laticeps, were tested for the ability to discriminate the odors of conspecific males from those of males of the broadly sympatric and closely related E. fasciatus, which is similar in appearance. Tongue‐flicks elicited in 1 min by male cloacal odors of both species presented to 28 males in counterbalanced order. Data were analyzed by one‐way analysis of variance (ANOVA) for a repeated measures design. Male E. laticeps had significantly higher tongue‐flick rates when responding to conspecific male odors than to odors of male E. fasciatus. The adaptive advantage of interspecific discrimination of male odors may be recognition of sexual rivals or avoidance of injury incurred during interspecific fighting.
Cortical granules products and fertility prevention in Bufo arenarum oocytes
Authors: Cabada Marcelo O. , Mariano Marta I. , Gómez Marta I.
Published: June 2005

A description of some properties of the cortical granule products (CGP) is provided. After activation, cortical granules (CG) discharge their content to the perivitelline space where most of these products remain. Two types of CGP preparations were used: one obtained by activating oocytes deprived of their vitelline envelope (tCGP), and the other obtained by activating oocytes covered by the vitelline envelope (vCGP). Both types of CGP were similar as regarding their capacity to modify oocyte sensitivity to spermatolysin. CGP modify the vitelline envelope (VE) of unactivated dejellied oocytes, which becomes insensitive to spermatolysin. This activity depends on both CGP concentration in the incubation media and the length of the incubation period. Once the effect of CGP on the oocyte is established it can not be completely eliminated by extensive washings, suggesting a lectin‐type association with the componenets of the VE. Treatment of dejellied oocytes with CGP results in fertility loss. The biological activity of CGP is related to thermolabile and nondialyzable substances. Lytic activity of spermatolysin on isolated VE is inhibited by CGP at a concentration at which trypsin inhibitors from soybean, lima bean, and ovomucoid are ineffective. The electrophoretic pattern of CGP indicates that most of the proteins present in the vCGP are derived from the VE. Ultrastructural modifications are observed in dejellied deposed oocytes after incubation with CGP.
Photoperiodic modulation of cephalic melatonin in planarians
Authors: Morita Michio , Hall Frederick , Best Jay Boyd , Gern William
Published: June 2005

Endogenous melatonin was detected by high‐performance liquid chromatography (HPLC) with electrochemical detection (EC) in the head of the planarian Dugesia dorotocephala. The identity of this elution peak was further confirmed by radioimmunoassay. In groups of planarians adapted to either normal or reversed photoperiods, the melatonin levels were always higher in those heads collected in the dark period than in those collected in the light period. This indicates that primitive animals such as planarians have already evolved a melatonin‐metabolizing system that is photically driven in a manner suggestive of the way melatonin synthesis is influenced by light and dark cycles in vertebrates.
Assay and subcellular localization of H2O2 generating mannitol oxidase in the terrestrial slug Arion ater
Authors: Malik Zulfiqar , Jones Carolyn J. P. , Connock Martin J.
Published: June 2005

An assay is described that allows the measurement of H2O2‐generating mannitol oxidase activity in sucrose‐containing homogenates and subcellular fractions. Using this assay high activity was found in digestive gland and crop of the slug Arion ater. The subcellular localization of mannitol oxidase in these tissues was examined using sucrose density gradient centrifugation in a B‐XIV zonal rotor. Mannitol oxidase was found to reside in a lowdensity membrane tentatively identified as golgi or plasma membrane, rather than in mitochondria or peroxisomes as had previously been supposed.
Adenohypophysial‐thyroid activity of the tiger salamander, Ambystoma tigrinum, as a function of metamorphosis and captivity
Authors: Norman Mark F. , Carr James A. , Norris David O.
Published: June 2005

The aim of this study was to determine the timing of adeno‐hypophysial activation during metamorphosis of the tiger salamander, Ambystoma tigrinum. It consisted of two parts: (1) determination of plasma thyroid hormone concentrations and analysis of thyroid gland histology as a function of metamorphic stage and (2) analysis of the time‐course of uptake of 125I by the thyroids during metamorphosis as an indicator of endogenous thyrotropin (TSH) levels. Significant increases in both triiodothyronine (T3) and thyroxine (T4) first were evident at the onset of metamorphic climax (stage II). Maximum levels of both hormones were not observed, however, until the completion of gill resorption (stage VII). No changes in thyroid histology were observed that could be unambiguously related to metamorphic transformation. The thyroids accumulated 125I in a slow but linear fashion in premetamorphic larvae (stage I). However, uptake exhibited a rapid peak during early climax (stage II), before maximum concentrations of thyroid hormones were observed. In addition, uptake was maintained above premetamorphic levels at stage VII, in conjunction with maximum levels of T4 and T3. Captivity alone produced a small but significant increase in plasma concentrations of T3. It produced no significant effect on either thyroid histology or uptake of 125I. These results indicate that adenohypophysial activation occurs rapidly and is maximal at the onset of metamorphic climax.
Effects of dehydroepiandrosterone on obesity and glucose‐6‐phosphate dehydrogenase activity in the lethal yellow mouse (strain 129/Sv ‐ Ay/Aw)
Authors: Granholm Nels H. , Staber Lisa D. , Wilkin Peter J.
Published: June 2005

We investigated the anti‐obesity effects of the adrenal androgen, dehydroepiandrosterone (DHEA), on genetically predisposed obese lethal yellow mice (AY/AW). Secondly, we tested the hypothesis that DHEA promotes its anti‐obesity effects by decreasing the activity of glucose‐6‐phosphate dehydrogenase (G6PHD). We subjected four genotype‐sex combinations of yellow and agouti (control) mice to four dietary treatments and determined weight changes, food consumption, and G6PDH activity. Although G6PDH activities of yellow mice were considerably decreased in the 0.4% DHEA treatment group, they were elevated in the 0.0 and 0.1% DHEA treatment groups. In contrast, G6PDH activities of DHEA‐treated control agouti mice remained relatively constant. These studies confirm that DHEA prevents the Ay gene from promoting excess fat deposition via some mechanism(s) other than reduced dietary intake. However, the overall absence of agreement between weight change (gain or loss) and G6PDH activity suggests that the anti‐obesity activity of DHEA is not mediated via G6PDH. Since yellow obese (Ay/Aw) mice were found to be more susceptible to DHEA's effects than their agouti (Aw/Aw) littermates, Ay appears to induce an altered metabolism in Ay/Aw mice which is more susceptible to the effects of DHEA than the normal metabolism of Aw/Aw mice.
Ultrastructural evidence of calcium uptake by chloride cells in the gills of goldfish, Carassius auratus
Authors: Ishihara Akiko , Mugiya Yasuo
Published: June 2005

Calcium uptake by the gills in goldfish (Carassius auratus) was observed by electron microscopy using an oxalate‐based method which specifically induced electron‐opaque precipitates in association with chloride cells in the primary epithelium. EDTA treatment and x‐ray microanalysis substantiated that these precipitates are a calcium salt. They were never found in deionized‐water‐adapted fish. Oxalate‐induced calcium precipitates, varying from 0.04 to 0.2 μl in diameter, occurred in the apical crypts of chloride cells and in large vacuole‐like structures in the lateral and basolateral regions of the cells. The crypts where the precipitates arose scatteringly had the morphological characteristics similar to the normal morphology of apical crypts: they were 2 to 4 μl in diameter and lined with darker and homogeneous cytoplasm with microridges. The vacuole‐like structures containing numerous calcium precipitates were somewhat irregular in contour and had a diameter of about 3 μl. They appeared to contact a densely distributed tubular system, but their limiting membrane was uncertain in the present resolution. The precipitates were concentrated in the central region of the structures. These results suggest that branchial calcium uptake is closely associated with chloride cells in goldfish.
Control of red cell volume and pH in trout: Effects of isoproterenol, transport inhibitors, and extracellular pH in bicarbonate/carbon dioxide‐buffered media
Authors: Nikinmaa Mikko , Steffensen John F. , Tufts Bruce L. , Randall David J.
Published: June 2005

The effects of extracellular pH and beta‐adrenergic stimula‐tion on the volume and pH of rainbow. trout red cells were studied in HCO3−/ CO2 butfered media. A decrease in extracellular pH caused an increase in red cell volume and a decrease in intracellular pH. The pH‐induced changes in cell volume were inhibited by 4,4′‐Diisothiocyanostilbene‐2,2′‐Disulfonic acid, (DIDS), an inhibitor of the anion exchange pathway, but not by amiloride, an inhibitor of Na+/H+ exchange, indicating that these volume changes are mainly associated with movements of chloride across the red cell membrane, and that the Na+/H+ exchanger is not activated by changes in intracellular pH alone. The adrenergic drug, isoproterenol, promoted cell swelling and proton extrusion even in the presence of 10 mM HCO3−, showing that the adrenergic response plays a significant role in the control of cytoplasmic pH. These responses were enhanced by a decrease in extracellular pH, showing that the adrenergic response is of benefit to stressed animals. DIDS markedly enhanced the effect of isoproterenol on the pHi, but abolished the increase in red cell volume. The effects of furosemide were similar to those of DIDS, suggesting that these transport inhibitors have a similar mode of action. Amiloride, on the other hand, inhibited both the volume and the pH changes associated with adrenergic stimulation. These observations support the double Na+/H+ and HCO3−/CI− exchange model of adrenergic swelling in fish red cells.
The oocyte of a new world marsupial, Monodelphis domestica: Structure, formation, and function of the enveloping mucoid layer
Authors: Phillips David M. , Fadem Barbara H.
Published: June 2005

Ovulated oocytes of the gray short‐tailed opossum Monodelphis domestica are surrounded by a thin zona pellucida and are devoid of a cumulus oophorus. In the ampulla of the oviduct, oocytes acquire a thick mucoid layer composed of concentrically arranged fibrillar material. Exocytosis by the secretory cells of the oviductal epithelium occurs in the region of the oviduct adjacent to the egg. This suggests that the oocyte‐zona‐mucus layer complex may influence the oviductal epithelium to secrete. During secretion, fibrillar contents of the secretion granules appear to be transformed into membranous material which presumably becomes fibrillar again as it is incorporated into the forming mucoid layer. Spermatozoa (which are known to pair in the cauda epididymis) are found in pairs and with intact acrosomes in the mucoid layer of fertilized eggs. This suggests that spermatozoa of Mondelphis remain paired until they reach the zona pellucida and that the acrosome functions in zona binding and/or penetration.
Genetic controls over melanocyte differentiation: Interaction of agouti‐locus and albino‐locus genetic defects
Authors: Lamoreux M. Lynn , Pendergast Phil
Published: June 2005

Tyrosinase activities and dopachrome conversion activity were evaluated in extracts made from skins of 6‐day‐old mice that were mutant at the agouti and albino loci. Dopa oxidase (DO) activity of tyrosinase in fully pigmented (C/C) mice is reduced in extracts made from skins of yellow 6‐day‐old mice as compared to those of black mice. Dopachrome conversion (DC) activity is absent from skin extracts of normal yellow mice and is present in normal black mice. DC activity is a characteristic of a separate enzyme which has been called dopachrome conversion factor or dopachrome oxidoreductase. We measured the dopa oxidase activity and dopachrome conversion activity in skin extracts of yellow mice and black mice that were mutant at the albino (C) locus. Extracts made from extreme‐dilution (ce/ce) mice do not have DO activity. Those from yellow extreme‐dilution mice do not have DC activity, while those from black, extreme‐dilution mice do. The DO and DC activities that characterize skin extracts made from platinum (cp/cp) yellow mice are similar to those of platinum black mice. These observations suggest possible mechanisms by which the functions controlled by the agouti and albino loci interact to control melanogenesis.
Male sterility caused by p6H and qk mutations is not corrected in chimeric mice
Authors: Handel Mary Ann , Washburn Linda L. , Rosenberg Michael P. , Eicher Eva M.
Published: June 2005

It is not known if the male sterility caused by the pleiotropic mutations p6H (pink‐eyed 6H) and qk (quaking) is intrinsic or extrinsic to spermatogenic cells. This question was addressed by juxtaposing mutant and normal cells in the testes of chimeric mice and determining whether the mutant germ cells could form functional sperm. Twenty‐one male chimeras consisting of normal cells and p6H/p6H or qk/qk cells were analyzed. For each, breeding productivity and testicular and sperm morphology were determined. Karyotypes and isozyme analyses were performed to identify the two cellular components of each chimera. All male chimeras that contained p6H/p6H, XY cells were sterile. Although some chimeras with a qk/qk, XY mutant component were fertile, none produced offspring from the homozygous qk component. Spermatids of the sterile chimeras showed abnormalities characteristic of the mutations.

We conclude from this study that the presence of normal XY germ and somatic cells in the testis did not rescue the male sterile phenotype of homozygous p6H or qk XY germ cells. Therefore, the action of these mutant genes in causing sperm abnormalities and sterility is autonomous to the germ cells.
On the diversity of sperm basic proteins in the vertebrates: V. Cytochemical and amino acid analysis in Squamata, Testudines, and Crocodylia
Authors: Kasinsky H. E. , Mann M. , Huang S. Y. , Fabre L. , Coyle B. , Byrd E. W.
Published: June 2005

The variability of sperm basic proteins in representatives of three reptilian orders, Squamata, Testudines, and Crocodylia, has been examined by cytochemistry, acid‐urea polyacrylamide gel electrophoresis, and amino acid analysis of amidoblack‐stained bands. Snakes contain type 3B intermediate sperm basic proteins by cytochemical criteria. Electrophoresis of basic proteins from epididymis chromatin as well as from testis and ductus deferens cell suspensions shows two fast‐moving bands in the vicinity of herring protamine. These proteines are triprotamines containing about 27 mol % arginine, along with lysine and histidine. Lizards have type 1 protamines in their sperm nuclei cytochemically and also show a two‐banded electrophoretic pattern similar to that of snakes. However, these proteins are triprotamines, similar to those in snakes with 25 mol % arginine. It may be that these are testisspecific proteins of the spermatid stage in lizards since a cytochemical transition can be observed from type 3A intermediate proteins in spermatids of testis to type 1 protamine in mature sperm of ductus deferens. Turtles contain type 3A intermediate sperm basic proteins cytochemically and basic proteins from epididymis chromatin display both a prominent band and a minor band close to, but slightly slower than, the two bands for snakes and lizards. Amino acid analysis of these bands shows that these basic proteins are also triprotamines but with a higher level of arginine, about 48 mol %, than that in snake and lizard sperm proteins. Basic proteins from epididymis chromatin of a single Mississippi alligator show three main bands moving close to the bands of snakes, lizards, and turtles. These proteins have amino acid compositions typical for triprotamines, with 28–39 mol % arginine. The data indicate that the sperm basic proteins of representatives of 25 species in three reptilian orders are very similar, in contrast to the diversity of sperm protein types found in frogs (Kasinsky, Huang, Kwauk, Mann, Sweeney, and Yee: J. Exp. Zool., 203:109–126, '78; Kasinsky, Huang, Mann, Roca, and Subirana: J. Exp. Zool., 234:33–46, '85a). This appears to be part of a macroevolutionary trend from diversity of sperm basic proteins in frogs to relative constancy in reptiles (Kasinsky, Mann, Pickerill, Gutovich, and Byrd, Jr.: J. Cell Biol., 91:1879, '81; Kasinsky, Mann, Lemke, and Huang: In: Chromosomal Proteins and Gene Expression, Plenum Press, New York, pp. 333–352, '85b). We present the hypothesis that one factor for such a trend resides in the fact that fertilization is internal in reptiles but external in anurans.