bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution of ammonia‐generating enzymes along the intestine of the earthworm, Lumbricus terrestris L
Authors: Tillinghast Edward K. , MacDonnell Paul C. 
Published: June 2005

AbstractThe linear distribution of ammonia‐generating enzymes (L‐serine dehydratase and 5′‐AMP deaminase) along the gut of Lumbricus has been examined using that of the digestive enzymes as a frame of reference.

This study confirms the observations of earlier workers indicating a high activity of digestive enzymes in the anterior region of the gut with declining activity toward the posterior.
5′‐AMP deaminase has a distribution paralleling that of the digestive enzymes. In contrast, L‐serine dehydratase is exclusively confined to the hindgut. It appears, therefore, that two potential centers for ammonia production exist in this species.
Chemical modification of cell type determination in Amphibian embryos
Authors: McDonald Ruth I. 
Published: June 2005

AbstractThe polyanion, polyethylene sulfonate, and the polycation, protamine sulfate, alter the epidermal differentiation of ventral ectoderm in the axolotl, Ambystoma mexicanum. Polyethylene sulfonate reverts stage 121/2 ventral ectoderm, determined to become epidermis, to ectoderm competent for neuralization, while protamine sulfate reduces the neuralization of stages 10½–11 ectoderm. Polyethylene sulfonate also decreases the basic protein staining in the nuclei of stage 121/2 ventral ectoderm and the amount of intense staining heterochromatic DNA in stages 12, 121/2, and 13 ectoderm. Protamine sulfate, in contrast, increases the basic protein staining and the amount of heterochromatic DNA in stages 11 to 14 ventral ectoderm. In addition, polyethylene sulfonate also causes a doubling of the mitotio index of stage 121/2 ventral ectoderm. On the basis of these results, the theory is proposed that the reversal in determination of stage 121/2 ventral ectoderm following polyethylene sulfonate involves decreased histone‐DNA binding and increased DNA replication.
The antigenic pattern of the developing brain of the zebrafish, Brachydanio rerio. II. Brain specific antigens
Authors: Laale Hans , Singh Lakheram 
Published: June 2005

AbstractOrgan and tissue supernates of the zebrafish, Brachydanio rerio, were analysed by immunoelectrophoresis with unabsorbed and absorbed rabbit antiserum to adult zebrafish brain. Four brain specific antigens were detected.
Microtubules, microfilaments, and pigment movement in the chromatophores of Palaemonetes vulgaris (Crustacea)
Authors: Robison W. Gerald , Charlton Jeannette S. 
Published: June 2005

AbstractThe glass shrimp, Palaemonetes vulgaris changes to match the color of its background by a rapid, so‐called physiological color change and a much slower, morphological color change. Apparently both are controlled by hormones, but the rapid color change is mediated by translocations of pigments within stellate cells called chromatophores, whereas the slow color change is effected by selective increases in certain types of chromatophore pigments. The large, dark chromatophores of the ovary were isolated intact and shown to be polychromatic (perhaps four pigments) by correlating light and electron microscopy. Incubated chromatophores supplied with crude extracts of certain neurosecretory tissues exhibit centripetal movement of pigment equivalent to that observed in vivo when a prawn is transferred from a dark‐colored background to a light‐colored background. Centripetal translocation of pigment is not inhibited in the chromatophores by preincubation in 10−3 M colchicine or vinblastine sulfate even though the vinblastine treatment elicits production of crystalline complexes of microtubular protein in place of the normal bundles of microtubules. Cytochalasin B (10 μg/ml) blocks pigment migration reversibly, but does not disrupt microfilaments or other ultrastructural elements. Apparently, normal pigment aggregation depends on some function which is reversibly sensitive to cytochalasin B, and not on the impressive system of microtubules in these cells.
Gas exchange in a cerianthid
Authors: Sassaman Clay , Mangum Charlotte P. 
Published: June 2005

AbstractAnalysis of the determinants of oxygen exchange in Ceriantheopsis americanus, a tubicolous anthozoan, indicates that in the natural habitat the site of oxygen entry is restricted to the tentacular crown. Predicted rates of oxygen diffusion solely across the marginal tentacles are sufficient to account for observed uptake rates in intact animals. The anatomical restriction of the site of exchange is, in part, a result of the absence of active irrigation of the tube. This pattern of gas exchange is more like that in epifaunal anemones than in a previously studied burrowing anemone.Gradual decline in ambient pO2 leads to a gradual decrease in oxygen consumption rate. Although the partial pressure differential across the exchange surface drops with declining ambient pO2, this decrease is not sufficient in itself to explain the relationship between oxygen consumption rate and ambient pO2. We suggest that differential oxygen sensitivities of the epidermis and gastrodermis and changes in surface area and diffusion distance during expsure to lowered pO2 may modify the oxygen consumption response.
The effects of an elevated temperature, colchicine, and vinblastine on axonal microtubules of the crayfish (Procambarus clarkii)
Authors: Hinkley Robert E. , Samson Frederick E. 
Published: June 2005

AbstractMicrotubules of isolated crayfish ventral nerve cords rapidly dissociate at 40°C and upon reincubation at ambient temperatures part of the microtubule population transiently reforms. Colchicine had little effect on the structure or number of intact microtubules of unwarmed nerve connectives, but vinblastine caused a decrease in microtubular numbers and led to the formation of typical paracrystalline arrays. After warming, both colchicine and vinblastine treatment prevented microtubule reassembly, presumably by interacting with the heat‐induced microtubular dissociation products, and led to the formation of axoplasmic inclusions. The inclusions seen in vinblastine‐treated prewarmed connectives were identical to the paracrystalline arrays produced in unwarmed preparations but the inclusions seen following colchicine treatment of warmed connectives have a unique appearance and are ultrastructurally distinct from vinblastine‐induced arrays.
Effect of a highly purified growth hormone on limb regeneration in the hypophysectomized newt, Notophthalmus viridescens
Authors: Bromley Stephen C , Thornton Charles S 
Published: June 2005

AbstractPreparations of ungulate growth hormone that have been used thus far to establish the role of that compound in supporting limb regeneration in hypophysectomized newts have contained significant prolactin contamination. Prolactin when present with thyroxin has been shown to be effective at low doses in supporting limb regeneration in these animals. The present communication demonstrates that a highly purified preparation of bovine growth hormone is able to support limb regeneration in hypophysectomized newts at essentially normal levels. Previous results indicating that prolactin and thyroxin in combination restore the regenerative response are corroborated. Thyroxin alone, or prolactin alone, gave a much reduced response. Purified growth hormone, while effective alone, is apparently antagonized by the presence of thyroxin.
Isocitrate lyase activity in the regenerating forelimb of the adult newt
Authors: Jasch Laura G. , Schmidt Anthony J. 
Published: June 2005

AbstractRegenerating and non‐regenerating limb tissues from the adult newt, Diemictylus viridescens, were assayed for isocitrate lyase activity. The enzyme assays were performed by micromodifications of existing procedures. In general, the whole homogenate, or a soluble fraction of the homogenate, was incubated with the substrate isocitrate. Isocitrate is cleaved by isocitrate lyase to glyoxylate and succinate. At the termination of the reaction, the 2,4‐dinitrophenylhydrazone derivative of glyoxylate was produced, extracted and quantitated spectrophotometrically. Isocitrate lyase activity was localized to bulb and two‐digit regenerates. The reaction product, glyoxylate (a monocarboxylic keto acid), was of special interest due to its role as a potent in vitro metabolic inhibitor. Therefore, the endogenous level of monocarboxylic keto acids, and the ability of regenerating tissue to produce and accumulate monocarboxylic keto acids, were investigated. Whole homogenates of regenerating tissue always contained more monocarboxylic keto acids than intact forearm or stump tissue. Also, after 30 minutes incubation with buffer alone, only regenerating tissue produced and accumulated additional monocarboxylic keto acids. In regenerating tissue, the isocitrate lyase reaction may be utilized in the metabolism of lipid. Since regenerating tissue can produce and accumulate monocarboxylic keto acids in vitro, glyoxylate produced by the isocitrate lyase reaction may accumulate in vivo and participate in metabolic regulation.
Helical polysomes in muscles of regenerating newt limbs
Authors: Deck J. David 
Published: June 2005

AbstractDuring the process of amphibian limb regeneration muscle fibers injured by the amputation lose their myofibrils and sarcoplasmic systems of membrane. Fragmentation of many of these dedifferentiated fibers to produce regeneration blastema cells has been reported numerous times by other investigators. The present work utilizing the electron microscope calls attention to dedifferentiated fibers that contain numerous helical polyribosomes and disorganized myofilaments. A number of polysome‐filled cells can be found beside mature muscle fibers as if in the process of fusing. In embryonic muscle, individual myoblasts containing helical polysomes fuse continually to form multinucleated fibers. The presence of the helical polysomes and myofilaments in sparsely fibrillar muscle elements of the regenerating limb, together with other features, is taken as evidence that the muscle elements are stages of regenerating fibers. These regenerating fibers can be found several days before the blastema becomes visible at the limb tip and are a normal part of the overall regeneration process. Indeed, tissue regenerative events marked by the appearance of helical polysomes become evident so soon after muscle injury/amputation that they imply a continuous but probably subliminal tissue turnover that is unmasked by the injury. According to the degree of injury, either the synthetic or the destructive phase of turnover might be favored, resulting in repair or extensive dedifferentiation of the individual fibers. Whether tissue regeneration or blastema cell formation thereafter occurs seems to be determined in part by the closeness of the fibers to the amputation surface.
In vitro analysis of gene depression in goldfish choroidal melanophores
Authors: Kajishima Takao 
Published: June 2005

AbstractThe common goldfish depigments its larval choroidal melanophores as well as the skin melanophores for about two to three months following hatching. Thereafter it begins to show a characteristic xanthic coloration. This depigmentation is under the control of depigmentation genes Dp1 and Dp2. The larval choroidal melanophores of the common goldfish were cultured in vitro for more than four months without showing any sign of depigmentation. During the same period the skin and choroidal melanophores in the control fish had completely depigmented. The addition of thyroid hormone and ACTH to the culture medium had no effect on depigmentation. The mechanisms of depigmentation in the goldfish are discussed.
Limb development in Diplopodia4: A polydactylous mutation in the chicken
Authors: Maccabe Jeffrey A. , Maccabe Astrida B. , Abbott Ursula K. , McCarrey John R. 
Published: June 2005

AbstractIn a study of the polydactylous mutation of the domestic chicken, diplopodia4, we have found that the genetic lesion affects primarily the mesoderm and only secondarily the ectoderm. The effect of this mutant mesenchyme on overlying ectodermal ridge, either mutant or normal, is to thicken the ridge preaxially, leading to increased outgrowth and preaxial polydactylism. A “zone of polarizing activity” in the normal limb‐bud seems to have a role in the control of its anteroposterior polarity. We have examined diplopodia4 limb‐buds for polarizing activity and found it to be normal in its activity and distribution. These results suggest that the supernumerary outgrowth in the mutant limbs result from increased ridge maintenance activity by the mesoderm without a concomitant increase in the activity or distribution of the polarizing zone.
On the mode of action of hydroxyproline in Drosophila development
Authors: Rapport E. W. 
Published: June 2005

AbstractHydroxyproline (OHP) fed to Drosophila larvae is known to impair the ability of pupae to evert cephalic structures and leg and wing discs. In order to gain insight into the metabolic basis of OHP action we have investigated the effects of combined feeding of OHP and several compounds. Proline, glucosamine HCl, and N‐acetyl glucosamine considerably reduced the extent of morphological defects of OHP, while alanine and sodium glutamate were less effective. Glutamine and glutathione did not reduce the effects of OHP. The results are consistent with the hypothesis that OHP may indirectly interfere with cuticle synthesis.
A new behavioral bioassay for an analysis of sexual attraction and pheromones in insects
Authors: Nissani Moti 
Published: June 2005

AbstractDrosophila melanogaster gynandromorphs were introduced into a mating chamber containing two wild type males. From the differential courtship responses of these males it could be concluded that the only important factor which enables a male to distinguish between conspecific males and females and to direct persistent courtship only toward females is tissue composition of females. This fact is interpreted in terms of a female‐specific sex pheromone. Most of this pheromone is produced by cells whose precursors on the blastoderm surface are very close to, or identical with, the blastoderm precursors of the tergites. Some of this pheromone is probably produced by cells whose precursors are very close to, or identical with, the precursors of the sternites and thorax.
Glycoprotein and protein antifreezes in two Alaskan fishes
Authors: Raymond J. A. , Lin Y. , DeVries A. L. 
Published: June 2005

AbstractTwo macromolecular freezing point depressants have been isolated from the serums of two species of Alaskan fishes. A common property of the four antifreezes thus far isolated is a high alanine content which suggests that the mechanism of these antifreezes may be related to a repeating tripeptide unit.
Comparative physiology and the challenge of design
Authors: Barrington E. J. W. 
Published: June 2005

AbstractAnalysis of the complexity of biological organization commonly takes us through an initial and necessary stage of over‐simplification towards the ultimate goal of an appreciation of the subtle intricacy of nature.One example of this is that recent advances in studies of the phosphagens Have failed to confirm earlier hopes that the distribution of these substances could be used to confirm phylogenetic relationships. It is now suggested that a previously unrecognized factor influencing this distribution may be competing demands for arginine in the development of the testes.Another illustration is the belief that the presence of iodine in ascidians may provide a clue to the origin of thyroidal biosynthesis. This belief is probably sound, but the presence of abundant iodine in the tunic may well be a false trail. More significant is the presence of much smaller amounts of bound iodine in the endostyle, where its presence is probably correlated with specialized protein metabolism associated with the ciliary feeding mechanism.A third illustration, discussed in more detail, is provided by recent recognition that the gut is a major component of the vertebrate endocrine system. This lays open attractive fields of research, ranging from problems of molecular and hormonal evolution to aspects of fish farming and the physiology of gut parasites.The need is thus plain for breadth of perspective in comparative physiological research, and for recognition that the ultimate concern of the biologist is with the life and relationships of the whole organism.
Multienzymic nature of pyruvate kinase during development of Hymenolepis diminuta (Cestoda)
Authors: Carter Clint E. , Fairbairn Donald 
Published: June 2005

AbstractH. diminuta at different stages of development contained as many as five pyruvate kinase isozymes. Four of these were unusually sensitive to allosteric activation by fructose‐1,6‐P2. One isozyme which occurred only in adults or near‐adults was insensitive but had a relatively low Km. All were inhibited by ATP and Ca2+, none by alanine, and the pH optimum was unaffected by fructose‐1,6‐P2. The five isozymes were present in gravid or reproductively active proglottids. Two of them occurred after eight days growth in the rat intestine, and three after four days. These three were also present in the immature, anterior proglottids of adult parasites. Hexacanth larvae from gravid proglottids, as well as cysticercoids developing from these larvae in Tenebrio molitor, possessed only two isozymes. It was inferred from information on tissue concentrations of ADP, ATP, phosphoenolpyruvate (PEP), and on K0.5s and Km that competition between pyruvate kinase and PEP carboxykinase is probably controlled by fructose‐1,6‐P2 concentrations. Since H. diminuta is an obligatory fermenter in which gluconeogenesis is minimal, the probable function of its L‐type pyruvate kinases is to control the specific composition of lactic, acetic and succinic acid mixtures that are excreted at different stages of development.
Effects of wheat germ agglutinin on fertilization of mouse ova in vivo and in vitro
Authors: Parkening Terry A. , Chang M. C. 
Published: June 2005

AbstractMouse ova with or without follicular cells (denuded) were treated with wheat germ agglutinin (WGA) in concentrations ranging from 5–500 μg/ml and fertilized in vitro. Ova subjected to concentrations greater than 10 μg/ml WGA were incapable of fertilization in vitro, although sperm were observed adhering to the zona pellucida after treatment in concentrations as high as 500 μg/ml WGA. At concentrations of 50 μg/ml or higher, WGA adversely affected the shape of the vitellus. Of various saccharides employed to block the effects of WGA D‐glucose was the most effective.Injections of 0.03 ml of 100 μg/ml or 500 μg/ml WGA into the ovarian bursa two to three hours before the expected time of ovulation had little or no effect on fertilization in vivo.
Frog lysozyme. I. Its identification, occurrence as isozymes, and quantitative distribution in tissues of the leopard frog, Rana pipiens,
Authors: Ostrovsky David S. , Snyder John A. , Iwata Takuzo , Izaka Ken‐Ichi , Maglott Donna S. , Nace George W. 
Published: June 2005

AbstractIn the course of examining the etiology of the Lucké renal adenocarcinoma of the frog, Rana pipiens, it was found that organs of the normal adult contain bacteriolytic enzymes. These enzymes all satisfied the six criteria for the identification of lysozymes and at least eight forms were separable by polyacrylamide gel electrophoresis. Their qualitative and quantitative distribution was organ‐specific. All eight isozymes were found in normal kidney, while liver and spleen contained seven forms; skin, six; ovarian egg, five; and serum, two.In quantitative assays using a radial diffusion test, spleen had the greatest lysozyme concentration, followed in descending order by kidney, liver, skin, and ovary. Serum contained very low amounts. In terms of enzyme activity per animal, ovary was the highest ranking organ. As such a large number of lysozyme isozymes has not been reported in any other organism, their origins and functions are considered in the context of their presence in an ectotherm.
Polarizing activity in the developing limb of the Syrian hamster
Authors: Maccabe Jeffrey A. , Parker Brenda W. 
Published: June 2005

AbstractThe transplantation of small pieces of tissue from the limb buds of 9 1/2 – 10 day hamster embryos to the wing bud of the chick results in the induction of supernumerary wing structures. The anteroposterior polarity of these induced structures is under the control of the transplanted hamster tissue. The developing hamster limb thus has limb polarizing activity similar to that found in avian species and, as in the chick, the activity is found primarily in the posterior region of the limb bud.
Mouse sperm genotype and the rate of egg penetration in vitro
Authors: Fraser Lynn R. , Drury Linda M. 
Published: June 2005

Abstract(C57BL/10 × CBA)F1 mouse eggs were incubated in vitro with either F1 or outbred TO sperm for 15 minutes‐6 hours. Upon removal from the sperm suspensions some eggs were treated with pronase to remove zonae and then cultured, while the remainder were simply cultured to allow a comparison of the fertilization rates in the two groups. Although a brief incubation was sufficient for a high rate of fertilization when the zonae remained intact, results from the zona‐free eggs indicated that penetration, i.e., sperm fusion with the vitellus, had not been achieved in all eggs during the shorter incubations. Results from the latter groups of eggs indicated that a 1 hour incubation with TO sperm and a 2 hour incubation with F1 sperm were needed to obtain a mean fertilization rate of 50%. Fertilization was complete within 1.5 hours using TO sperm and 2.5 hours using F1 sperm, thus indicating that under similar environmental conditions sperm genotype can significantly affect the rate of penetration.
Humoral immune responses in Rana catesbiana frogs and tadpoles
Authors: Pross Susan H. , Rowlands David T. 
Published: June 2005

AbstractRana catesbiana adult frogs and tadples were immunized with the bacteriophage F2, ϕX‐174, and T4 and the haptens 2,4 dinitrophenyl (DNP) and fluorescein (FTC). The haptens were conjugated with bovine serum albumin (BSA), bovine gamma globulin (BGG), or horseshoe crab hemocyanin (Hycn). Sera were obtained from immunized animals at intervals up to six months after immunization. The antibody activities were measured by bacteriophage neutralization techniques. Sucrose density gradients were used to separate the antibody classes.Both adults and tadpoles responded to each of the antigens tested. High molecular weight antibodies were predominant in both groups of animals. Low molecular weight antibody activity was not found in adults until nine weeks post immunization but, thereafter, this fraction increased throughout the immune response. Low molecular weight antibodies could also be identified in serum of tadpoles, but only under certain conditions.
Failure of XX cells containing the sex reversed gene to produce gametes in allophenic mice
Authors: Gordon Jon 
Published: June 2005

AbstractAllophenic mice have been produced by combining embryos from normal albino mice with embryos of normally pigmented mice carrying the autosomal dominant for sex reversed (Sxr) in order to determine the ability of XXSxr cells to differentiated either into sperm or eggs. Sixteen male and six female allophenes have thus far produced more than 1,200 offspring, none of which arose from an XXSxr primordial germ cell. Two allophenic mice were sterile hermaphrodites, and 13 others have yet to be tested. These results indicate that an XX cell is incapable of spermatogenesis even when supplied with the male determining Sxr gene, and that this gene also prevents XX cells from undergoing oogenesis. The latter result contrasts with a previous report of a functional sex reversed oocyte in the mouse.