bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal effects of hyper‐osmotic sodium chloride on urea production in the frog, Rana pipiens
Authors: Jungreis Arthur M.
Published: June 2005

Spring‐summer frogs, Rana pipiens, acclimated at 22.5°C or 27°C were dehydrated in 0.15 M NaCl for up to 24 hours. After 10 or 24 hours of treatment, the concentration of urea in serum increases relative to the concentrations of urea measured in serum of frogs kept in tap water or 0.125 M NaCl.

The increase in the concentration of urea in serum of spring‐summer frogs was associated with an increase in body urea and an increased rate of urea production.

When fall‐winter frogs, acclimated at 20°C, were dehydrated in 0.15 M NaCl for 12.5 hours, no increase in the concentration of urea in serum was observed, relative to frogs treated with tap water or 0.125 M NaCl. After 48 hours, the concentration of urea in serum of frogs treated with 0.15 M or 0.125 M NaCl was the same, but both were significantly greater than tap water treated frogs.

The metabolic basis for the increase in the rate of urea production observed in spring‐summer but not fall‐winter frogs in response to hyperosmotic sodium chloride is discussed.
Bearing of genetic data on the interpretation of the subunit structure of octanol dehydrogenase of Drosophila
Authors: Ogonji Gilbert Odhiambo
Published: June 2005

Genetic analysis of A, B, and B′ octanol dehydrogenase isozyme variants extracted from five geographic strains of Drosophila albirostris isozyme variants shows that these are distinguished by multiple alleles at one locus. A comparison of isozyme patterns of single fly and mass homogenates of true breeding variants and of their hybrids suggests that the difference in the variants are due to a regulatory locus. A tetrameric enzymatic structure, stemming from the activity of two structural genes, can account for the isozymes found in electrophoretic positions 3 to 7.
Regulation in grafts of partially dissociated and reaggregated portions of Fundulus embryonic shields
Authors: Oppenheimer Jane M.
Published: June 2005

Portions of Fundulus embryonic shields, usually posterior or anterior halves, were partially dissociated into cell clumps and separate cells by exposure to salt solution lacking magnesium and calcium ions; the dissociates were reaggregated in salt solution containing these ions, then immediately grafted to extraembryonic regions of host gastrulae. Technical difficulties prevented complete dissociation of the shield portions and complete retrieval of the dissociates, but a number of hosts bearing secondary complexes differentiated in association with the grafts developed successfully to late stages.

Complexes associated with grafts derived from posterior shield portions frequently formed tails, and differentiated, with few exceptions, the same range of structures described earlier as having differentiated when either unfragmented or mechanically minced shield portions were grafted. In the parts of the new graft complexes remaining attached to the yolksac epithelium, the secondary structures formed were often in topographic disarray, but in the free tails that grew out from these complexes, the axial structures frequently attained normal topographic relationships.

Complexes associated with grafts derived from anterior shield portions frequently formed, among other structures, highly differentiated eyes, often with normal retinal stratification, sometimes accompanied by lens, cornea, iris, or optic nerve.

The high degree of organization of tails developing in association with grafts of posterior origin, and of eyes in association with grafts of anterior origin, is possibly explicable not by cellular self‐sorting and self‐assembly, but rather by embryonic field phenomena.
DNA base sequence heterogeneity in the order galliformes
Authors: Schultz Gilbert A. , Church Robert B.
Published: June 2005

Nucleotide substitution that has occurred in the repeated DNA base sequences of several species of galliformes since their origin has been investigated by DNA/DNA hybridization. The results of competition experiments and the thermal stabilities of interspecific DNA/DNA hybrids indicate that a considerable amount of base substitution has occurred between species within the Family Phasianidae. A specific group of genes, the ribosomal RNA cistrons, have been found to be conserved relative to the average DNA base sequences. Gallus domesticus DNA shows considerable base sequence heterogeneity with respect to Phasianus colchicus DNA and is about as divergent from the other members of the Family Phasianidae as are some species outside the family.
Activity and localization of acid hydrolases in the dorsal tail fin of Rana pipiens during metamorphosis
Authors: Greenfield Phyllis , Derby A.
Published: June 2005

The specific and total activities of acid phosphatase (AcP), hyaluronidase (HU), β‐N‐acetylglucosaminidase (NAG) and lactate dehydrogenase (LDH) of tail fin are constant during prometamorphosis. During climax, as the fin is resorbed, the activities of the hydrolases increase while the specific activity of LDH remains constant and the total activity decreases. The apparent Km and pH optimum of the hydrolases are the same at prometamorphosis and climax. Similar changes in enzyme activities are found in pieces of prometamorphic fin induced to resorb in vitro by thyroxine treatment. AcP, NAG and LDH are found, but in different proportions, in both fragments of prometamorphic fins separated into epidermis and mesenchymal core. NAG and LDH are more concentrated in the epidermis while AcP is more concentrated in the core. A higher percentage of NAG and AcP activity is found in the mitochondrial‐lysosomal and supernatant subcellular fractions at climax than at prometamorphosis. In addition, the specific activities of these enzymes are higher in the mitochondrial‐lysosomal and supernatant fractions at climax while the specific activity and subcellular distribution of LDH is constant. The increase in activity of the hydrolases of the fin which occurs in synchrony with resorption during spontaneous metamorphosis or that induced in vitro by thyroxine suggests that these events are related and that the hydrolases are concerned with the degradation of the connective tissues of the fin during regression.
Local action of thyroxine on amphibian metamorphosis. V. Cell division in the eye of anuran larvae effected by thyroxine‐cholesterol implants
Authors: Kaltenbach Jane Couffer , Hobbs Ann Witherell
Published: June 2005

To determine whether or not thyroxine stimulates cell division in the tadpole eye by acting directly upon ocular tissues, thyroxine‐cholesterol and cholesterol control pellets were implanted into the vitreous chambers on opposite sides of young Rana larvae. From 1 to 20 days later some of the larvae were exposed to tritiated thymidine. Scintillation counting indicated more radioactivity in the thyroxine‐treated eyes than in the contralateral control eyes, and radioautography showed that it was located in nuclei in the ora serrata of the retina and in the epithelia of the lens and cornea. Mitotic figures were found in similar locations in the eyes of tadpoles fixed at five day intervals, up to 45 days after pellet implantation; striking increases in mitotic activity were induced in the eyes containing thyroxine implants. As long as 35 days post implantation there was little, if any, advancement of metamorphic changes in other regions of the tadpoles including such structures as the hind limbs and the control eyes; even development of accessory ocular structures near the thyroxine‐treated eyes (such as eyelids, nictitating membrane and extrinsic ocular muscles) was not enhanced. The precocious unilateral stimulation of cell division in the retina, lens, and cornea of eyes containing thyroxine implants indicates a direct, local action of thyroxine upon ocular tissues. This suggests that during normal metamorphosis cell division in the eye is probably brought about by the direct, peripheral action of thyroid hormone.
Sperm penetration through zona pellucida and perivitelline space in the hamster
Authors: Yang W. H. , Lin L. L. , Wang J. R. , Chang M. C.
Published: June 2005

Sperm penetration through zona pellucida was observed in tubal fluid containing eggs and spermatozoa, which had been recovered under a layer of paraffin oil previously insufflated with a mixture of 5% CO2 and 95% air and warmed to 38°C before each experiment. A Nikon F 35 mm camera and a Bolex Rex‐5 16 mm movie camera, synchronized with Xenon‐gas flash epuipment, were used with a microscope for recording this fast‐occurring phenomenon. In golden hamsters, 284, 306, 312 and 293 tubal eggs were recovered in paraffin oil after 4, 4.5, 5 and 5.5 hours, respectively, following delayed mating; 1, 11, 13 and 8 eggs were observed to be either attached or approached by spermatozoa, of which 1, 9, 10 and 1 eggs respectively were subsequently penetrated by the spermatozoa. The change in the CO2 tension of the paraffin oil had no apparent effect on the incidence of in vitro fertilization. Nevertheless, either the containment of eggs and spermatozoa in the small space between a cover slip and glass slide, or the dilution of tubal fluid with the liquid medium of 0.1 ml hamster serum and 0.4 ml CDM 199 was detrimental to the in vitro environment of fertilization. As in a previous investigation, most spermatozoa penetrated obliquely through the zona pellucida, but very few spermatozoa penetrated directly through it. The duration of time for spermatozoa to traverse the zona pellucida varied from about 4 to 22 minutes. Although almost all tubal eggs were completely penetrated as a result of fertilization in the oviduct of golden hamsters, yet a rather high percentage, 36%, of spermatozoa penetrated incompletely through the zona pellucida in vitro. Following sperm penetration through the zona pellucida, the vibration of ooplasm was initially induced by the impact of the two gametes, and then the rotation of ooplasm was subsequently caused by the migration of spermatozoa in the perivitelline space. Nearly 40 hamster eggs were observed and photographed in vitro during the process of fertilization, the largest number of mammalian fertilizations yet reported.
The passage of extracellular tracers through the follicular epithelium of lizard ovaries
Authors: Neaves William B.
Published: June 2005

Lanthanum, a tracer of extracellular space in fixed tissue, readily traverses the follicular epithelium of the lizard Anolis carolinensis. Saccharated iron oxide injected into living lizards and peroxidase administered in vitro pass through the extracellular spaces of the follicular epithelium and accumulate in the zona pellucida. Micropinocytotic uptake of iron and peroxidase by the oocyte occurs in larger follicles which show signs of yolk accumulation. These findings confirm the morphological absence of sealing junctions in the follicular epithelium and demonstrate an extracellular route whereby materials carried in the circulation may reach the oocyte without passing through the cytoplasm of follicular cells.
Distribution of the cytoplasmic activity inducing germinal vesicle breakdown in frog oocytes
Authors: Masui Yoshio
Published: June 2005

Full‐grown oocytes of Rana pipiens were dissected out of the follicles and induced to undergo germinal vesicle breakdown (GVBD) in vitro by progesterone treatment. When the progesterone treatment was carried out after displacing the germinal vesicle (GV) from the animal half to the vegetal half by centrifugation (200–400 × G for 10 minutes), a considerable delay of GVBD took place although all the GVs eventually broke down. GVs displaced near the vegetal pole frequently migrated towards the animal pole and gave off a polar body in the equatorial zone of the oocyte. When an oocyte was tightly constricted along the equatorial line with thread so that the migration of the GV was prevented, the frequency with which the GV broke down in the vegetal half was considerably decreased depending on the tightness of constriction. The ooplasm in the animal and vegetal halves of the progesterone‐treated oocytes was tested for GVBD inducing activity by injecting it into untreated oocytes which contain an intact GV. It was found that the ooplasm from the vegetal half induced GVBD in the recipients with a lower frequency than that from the animal half. To localize the GVBD inducing activity in the ooplasm, oocytes were centrifuged after progesterone treatment at the interface between Ringer's solution and Ficoll solution. The GVBD inducing activity of the ooplasm of the animal pole was increased after removal of yolk and pigment granules by a brief centrifugation (4000 × G for 5–10 minutes). Prolonged centrifugation (4000 × G for 2 hours) brought about stratification of the ooplasm. From the centripetal to the centrifugal side, five layers were distinguished: oil cap, fluid hyaline ooplasm, gelatinous hyaline ooplasm, pigment granules and yolk. The highest activity of GVBD induction was found in the hyaline ooplasm. Based on these results, a mechanism of the GVBD induction in the frog oocyte is discussed.
Changes in macromolecular synthesis in Triturus presumptive epidermis stimulated by inducing agent
Authors: Imoh Hiroshi , Sasaki Naoi , Kawakami Izumi , Hayashi Hirofumi
Published: June 2005

Syntheses of macromolecules, DNA, RNA, and protein, were studied in isolated presumptive epidermis of Triturus gastrulae using radio active carbon dioxide as tracer.

The explants cultured in the absence of inducing agents synthesized DNA, RNA, and protein for at least three days after explantation. Throughout the three days, DNA synthesis continued at an almost constant rate and patterns of newly synthesized proteins fractionated on polyacrylamide gel electrophoresis were similar. Activation of ribosomal RNA synthesis was observed to occur during culture. These facts suggest that, in the explants cultured in the absence of inducing agents, cell multiplication continued and the set of proteins synthesized changed little over a three‐day period.

In the explants in which structures were induced by rat liver homogenate, syntheses of macromolecules differed from those in the control in some respects. There was a peak of active DNA synthesis around ten hours after induction treatment, and the phase of DNA synthesis was followed by active RNA synthesis. After three days of induction the pattern of newly synthesized proteins obtained by gel electrophoresis differed greatly from that seen earlier in the induction process and from that of controls.
Developmental biology of annual fishes. I. Stages in the normal development of Austrofundulus myersi Dahl
Authors: Wourms John P.
Published: June 2005

Comparative studies of annual fish development reveal a unique developmental pattern in which embryogenesis occurs within a reaggregated mass of previously dispersed cells. The normal development of Austrofundulus myersi Dahl, a representative annual fish, has been divided into 46 stages. Cleavage during Stages 1–11 produces a typical teleost blastula. At Stage 12 (a flat, hollow blastula), the blastomeres segregate into two populations. One population composed of deep blastomeres will disperse as amoeboid cells, while the other, an hemispherical shell of outer blastomeres, flattens to form the enveloping cell layer. The cells of the enveloping cell layer become multinucleate and the layer functions as an extra‐embryonic membrane which is shed at hatching. When epiboly commences (Stage 14), the deep blastomeres come together as a consolidated mass and then migrate outward as individual amoeboid cells into the space formed between the expanding enveloping cell layer and periblast. When epiboly is concluded (Stage 19), the deep blastomeres have completely dispersed over the surface of the periblast. The dispersed phase usually lasts for several days. Prior to epiboly and during the dispersed phase, no germ ring, embryonic shield, or axial organization is present. The dispersed cells come together to form a definitive aggregate (Stage 22) by day 4. Embryogenesis within the reaggregated mass of previously, dispersed cells produces a typical teleost embryo. The definitive embryonic axis and solid neural keel appear by Stage 28 (day 10). Growth and organogenesis proceeds and hatching occurs at Stage 44. Development through Stage 44 requires 39–40 days in non‐diapausing eggs. Eggs of A. myersi may enter diapause at three distinct stages: (1) dispersed cell phase; (2) long somite embryo; and (3) late pre‐hatching.
Physiological effects of trypan blue on chick embryos
Authors: Hoffman David J. , Ramm Gordon M.
Published: June 2005

Ten‐day chick embryos (1) received yolk sac injections of 0.1 ml of 1.5% trypan blue in sterile saline, (2) received 0.1 ml of sterile saline or (3) were handled and returned to the incubator and examined five hours later. Trypan blue treated embryos exhibited decreased survival rate and significant decreases in plasma glucose, chloride, CO2 content and blood pH. Plasma potassium and embryonic wet weight were significantly elevated, but little change occurred in plasma sodium or hematocrit. Embryos frequently exhibited hemorrhaging after treatment. Saline treatment caused a small but significant decrease in plasma chloride and only a slight decrease in survival rate.

The immediate response to trypan blue was markedly similar to that of hypoxia, presenting additional evidence in support of the view that trypan blue may interfere with the normal oxygen consumption of the embryo.
An ultrastructural study of strobilation in Chrysaora quinquecirrha with special reference to neurosecretion
Authors: Crawford Marsha A. , Webb Kenneth L.
Published: June 2005

Scyphistomae and strobilae of the scyphozoan Chrysaora quinquecirrha were fixed and sectioned for electron microscopy. The polyps were divided into four classes on the basis of their stage of development: non‐strobilating (scyphistomae), neck‐formation, segmentation, and metamorphosis. Ultrastructural preparations revealed neurosecretory cells containing numerous membrane‐bounded granules in scyphistomae and necked polyps. At the time of neck‐formation the neurosecretory granules were mpst concentrated in the cell body and at segmentation, most concentrated in the axons of the neurites. By metamorphosis most of the neurosecretory product had disappeared from the axons. Other changes which appear to accompany strobilation included both a decrease in glycogen and contraction of muscles along the inner edge of the epidermis.
The relationship of gonadogenesis, molting and growth during postembryonic development of the free‐living nematode, Panagrellus silusiae: Selective inhibition of gonadogenesis using hydroxyurea
Authors: Westgarth‐Taylor B. , Pasternak J.
Published: June 2005

During postembryonic development of the free‐living nematode, Panagrellus silusiae, there are three diverse developmental processes: growth, molting and gonadogenesis. By treating synchronously growing worms with hydroxyurea at various times during the postpartum period it was possible to induce selective blockage of gonad formation without interfering appreciably with the temporal patterns of growth or molting. Gonad formation was differentially susceptible to hydroxyurea treatment. The presence of the drug during the early phases of gonadogenesis prevented completion of the process while administration later in the postpartum cycle was without effect.

Long term treatment with hydroxyurea caused cuticular anomalies in adult
worms after the final molt had been completed.

Treatment with puromycin, actidione, actinomycin D, cold or removal of
nutrients during the early stages of postpartum development reversibly blocked
postembryonic development. Nitrosoguanidine blocked postembryonic develop
ment irreversibly.

The results suggest that gonad development is not obligatory for growth or
molting but continued body growth and molting are essential for gonado
genesis. It was not possible to divorce the molting process from body growth.
Pituitary‐adrenal interaction and growth of the embryonic avian adrenal gland
Authors: Girouard R. J. , Hall B. K.
Published: June 2005

Possible interactions between the anterior pituitary and the adrenal gland in the embryonic chick were investigated. Hypophysectomy by partial decapitation, and treatment of embryos with dexamethasone phosphate (a potent corticosteroid) both significantly reduced the growth of the adrenal gland, indicating a dependence of the adrenal gland on the pituitary for normal growth and the potential for negative feedback between the adrenal and the pituitary.

The hyperplasia of the host adrenal gland known to follow injection of
homogenates of adrenal glands was inhibited when homogenates were injected
into embryos whose ACTH production had been inhibited by dexamethasone.
It was concluded that the response of the embryonic adrenal gland to growth
stimulating agents was mediated via the anterior pituitary.
L(+)‐lactate dehydrogenases from Hymenolepis diminuta (Cestoda)
Authors: Walkey Michael , Fairbairn Donald
Published: June 2005

Properties of L( + )‐lactate dehydrogenases from infective eggs, cysticercoids, immature proglottids (anteriors), and pre‐patent (seven day) infections of H. diminuta were studied. Fractionation of isozymes by disc gel and cellulose acetate electrophoresis was unsatisfactory, but some fractionation was obtained by electrofocusing. Other evidence suggested that one form of LDH predominated in eggs and cysticercoids, and a second form in anteriors and pre‐patent worms. The first form was relatively resistant to thermal inactivation and was only slightly inhibited by pyruvate. The second resembled LDH−1 of mammals in being strongly inhibited by pyruvate, even though it occurred in life cycle stages that require no oxygen for grbwth and differentiation. In all tissues Km (lactate) was about 50–100 × Km (pyruvate), but Km (pyruvate) was much higher in eggs and cysticercoids (2.8 × 10−4) than in anteriors and pre‐patent worms (2.8 × 10−5 mole/li). Energies of activation were 8,419, 13,870, 16,107, and 22,633 cal/mole in cysticercoids, eggs, pre‐patent worms, and anteriors, respectively. In eggs and cysticercoids Km (pyruvate) passed through a minimum at 20−25°C, suggesting that LDH in these tissues may function efficiently at normal environmental temperatures. Anteriors and pre‐patent worms did not exhibit such a correlation.
Unscheduled synthesis of DNA during mammalian spermatogenesis in response to UV irradiation
Authors: Gledhill Barton L. , Darżynkiewicz Zbigniew
Published: June 2005

Unscheduled incorporation of tritium‐labeled thymidine into nuclear DNA, induced by UV irradiation and presumed to indicate DNA repair replication, has been followed in differentiating male germ cells of the rat and rabbit by quantitative autoradiographic techniques. Cells at various stages of differentiation incorporated [3H] thymidine at different rates. The maximal rate was observed in nuclei of pachytene primary spermatocytes; the rate was markedly lower in spermatogonia and in leptotene and zygotene primary spermatocyte nuclei. No evidence of incorporation was found for nuclei of spermatids and testis spermatozoa.
Normal embryonic stages for salmonid fishes, based on Salmo gairdneri Richardson and Salvelinus fontinalis (Mitchill)
Authors: Ballard William W.
Published: June 2005

As a byproduct of a re‐examination of teleost morphogenetic movements, 23 stages in the normal development of salmonid fishes are presented, from fertilization to and beyond hatching, together with rates of their appearance at several constant temperatures. To aid in planning experiments, the period before closure of the germ ring is divided into 13 stages, with detailed discussion of internal structures and movements as well as external features, especially during gastrulation. The literature of salmonid development suggests that the stages are closely applicable to the embryos of any genera of Suborder Salmonoidei. except as to the rates of their appearance. Illustrations are designed for ready identification of stages. Tofacilitate their correlation with the older morphological literature, the principal events of organogenesis in the ectodermal, mesodermal, and endodermal categories are listed according to the stages at which they occur, as determined by dissections and serial sections.
An analysis of urodelian retinal regeneration: IV. Studies of the cellular source of retinal regeneration in Triturus cristatus carnifex using 3H‐thymidine
Authors: Keefe J. Richard
Published: June 2005

The process of retinal regeneration in adult Triturus cristatus carnifex was analyzed autoradiographically following tritiated thymidine administration at closely spaced postoperative intervals. In unoperated control animals given five daily doses of labeled thymidine, a continuous input of two types of cells was observed from the ora serrata into the ganglion cell and inner nuclear layers. One cell type appeared to represent retinal neurons with dispersed nuclear chromatin while the second cell type, containing a nucleus with dense heterochromatic rim, was displaced into all retinal layers with time, ultimately appearing within the layer of photoreceptor outer segments approximating the pigment epithelium. In operated animals, both control and operated (enucleated) eyes showed a loss of proliferative capacity from the ora serrata by two days postoperative.

Retinal degeneration and regeneration in this species differed from that observed earlier for Notophthalmus viridescens in that: (1) invading pigment epithelia dissected the degenerating retina sequestering the outer nuclear layer between two epithelial sheets for phagocytosis by day 8; (2) degenerating inner retinal cells demonstrated labeling with thymidine and mitotic division before degeneration; (3) the process of removal of retinal and lens debris was assisted by vascularly derived phagocytes. The restoration of the retina involves both cellular addition from the anterior pars ciliaris retina and ora serrata, forming the anterior half of the new retina, and the posterior pigment epithelium, forming the posterior half of the retina from the innermost lamina. Sites of regional cellular proliferation at the vortex veins do not develop in this species. The basal pigment epithelium, upon Bruch's membrane, does not contribute to the retinal regenerate.

The species differences presented in the process of retinal regeneration and the implications for the understanding of the generation of retinotectal specificity are discussed. It is concluded that the specificity engendered during both development and regeneration in this system must: (1) be derived from the ganglion cells; (2) be responsible for not only tectal connections but intra‐retinal position and connectivity; and, (3) not be temporally related.
The effects of aging on in vitro fertilization of rabbit eggs and subsequent embryonic development
Authors: Fraser Lynn R. , Dandekar Pramila V.
Published: June 2005

Rabbit eggs, with or without folliculai cells, are highly fertilizable in vitro (Fraser et al., »71). In vitro aging of intact, cumulus‐devoid, and corona‐devoid rabbit eggs did not appreciably lower their subsequent fertilizability in vitro with fresh sperm. The intact and cumulus‐devoid eggs were somewhat less fertilizable than the corona‐devoid eggs when aged for two and one‐half hours (70%, 68%, 91%, respectively), but this difference disappeared when the aging period was six hours (83%, 82%, 91%) or 12 hours (83%, 81%, 82%). Chromosome complements ranged from hypodiploid to polyploid in all groups, regardless of time of aging. Viability of embryos from the three groups, as determined by continued cleavage in vitro, was much reduced when compared to that of unaged eggs similarly cultured. There was no observable correlation between ploidy and development in culture; polyploid complements, particularly triploids, were found in both advanced and retarded stages.

The possible effect of aging at an earlier time was noted in studies involving transfer of two to four cell embryos to pseudopregnant recipients. Embryos derived from eggs recovered 13 hours post‐LH and fertilized in vitro had low implantation rates and none of the implants developed to full term fetuses. However, the development of embryos from eggs recovered 12 hours post‐LH was not significantly different from embryos fertilized in vivo and cultured prior to transfer; 21% and 24%, respectively, of the embryos transferred developed to term.

A number of the offspring have been raised to maturity. Those from the in vivo fertilized embryos have appeared normal and their eggs and sperm have had no obvious defects. From a similar sample size of in vitro fertilized offspring, 2/14 have displayed defects of the limbs resembling a condition termed splayleg, thought to be a recessive genetic trait. Whether conditions of in vitro fertilization might favor the union of two gametes carrying the recessive gene is not known.
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. II. Reactivation, substrate specificity, activators, and inhibitors
Authors: Schmidt Waldemar A.
Published: June 2005

A medullary nucleotide phosphatase activity can be demon‐strated in fixed mature S. purpuratus eggs. However, this enzymatic activity is lost from eggs stored for more than four days in a Michaelis buffer prepared in distilled water. The activity can be reinstituted by overnight incubation in sea water or solutions of its major cations, prior to reacting for enzymatic activity.

The substrate characteristics of this nucleotide phosphatase system indicate that the activity is not due to nonspecific acid or alkaline phosphatases, organic or inorganic pyrophosphatases, or hexose phosphatases. The activity is present with ATP and other nucleoside tri‐, di‐, and monophosphates and is most accurately labelled as a nucleotide phosphatase.

The effects of various selected enzymatic activators and inhibitors upon the nucleotide phosphatase activity, demonstrated with ATP as substrate, are also presented. This activity is inhibited by L‐cysteine, glutathione, sodium fluoride, sodium tartrate, and zinc chloride; not inhibited by p‐chloromercuribenzoic and mersalyl acids; and stimulated by 2,4‐dinitrophenol, sodium azide, iodo‐acetamide, and ouabain. These data indicate some similarities with other phosphatases, but there are discriminating differences which label the enzyme system as a distinct entity.
Nucleotide phosphatase in Strongylocentrotus purpuratus eggs. III. Multiple enzymatic activities in mature and immature eggs
Authors: Schmidt Waldemar A.
Published: June 2005

On the basis of reaction patterns of eggs treated with activators and inhibitors and selected reactivating agents, there are at least three separate nucleotide phosphatase activities identifiable in maturing sea urchin eggs. Of these activities, the first two are sensitive to K + and Mg + +, respectively. The third activity is enhanced by both Na + and Ca + + and may represent two separate enzymes. These enzymatic activities are associated with different localizations and lead to a hypothesis of changing enzymatic patterns and localizations during the course of oogenesis.
The formation of the feeding organelle in Paramecium aurelia
Authors: Hanson Earl D. , Ungerleider Ross M.
Published: June 2005

The control of formation of the feeding or buccal structures in Paramecium aurelia has been studied by damaging or eliminating this organelle by means of a microbeam of ultraviolet light and following the fate of treated cells through subsequent fissions and autogamy. Homopolar doublets, with two sets of buccal parts per cell, provided one set as a control and to feed the cell while the other was used experimentally. The evidence shows that buccal morphogenesis is not simply self‐assembly of gene products but depends also on pre‐existing cytoplasmic differentiations of the cell.
Characteristics of hairs and related mechanoreceptors in the mouse and rabbit
Authors: Straile William E. , Mann Stanley J.
Published: June 2005

Certain distinctive forms of hair act as levers for specific tactile receptors. Thus, information about hair structure can be used to locate and compare receptors among species and among different body areas. For example, the tylotrichs and bristles in both mice and rabbits activate special groups of receptors in the dermis, and the tylotrichs also displace innervated Merkel cells in the epidermis. Each of these hairs has definite structural features, which include a long graduated tip and wide shaft. This basic form characterizes all of the tylotrichs or bristles that grow in succession within a single follicle and related nerve cylinder during the life‐span of an animal. Most of the other hairs in mice have short tips and have narrow shafts with one or more constrictions. A short‐tipped hair with one constriction as well as a hair with three constrictions can grow through the same follicle and nerve cylinder in different hair growth cycles. Variations in hair constrictions probably have no bearing on receptor identification but must be investigated and thus eliminated as sources of confusion. There are more constrictions in first‐generation hairs than in the hairs formed in subsequent growth cycles. First‐generation hairs activate densely distributed receptors in a thin juvenile integument, whereas the less constricted hairs in adult animals activate receptors that are widely separated in a thick, fully expanded integument.
Specialized lactate dehydrogenase isozymes: The molecular and genetic basis for the unique eye and liver LDHS of teleost fishes
Authors: Shaklee James B. , Kepes Kathryn L. , Whitt Gregory S.
Published: June 2005

Electrophoretic and immunochemical analysis of the lactate dehydrogenase isozyme patterns of fishes indicates that these isozymes are the tetrameric products of three LDH loci — A, B, and C — which are present in virtually all teleost fishes. The A and B genes of fishes and their corresponding isozymes have previously been shown to be homologous to the A and B genes of other vertebrates. The eye‐band LDH characteristic of many groups of teleosts, and the liver‐band LDH of gadoid and cyprinid fishes are shown in this report to be encoded in the same LDH locus, designated C. In different groups of fishes this third LDH gene (C) is extremely varied both with regard to its tissue‐specific regulation and with regard to the physical properties of its corresponding subunit. The electrophoretic mobility of the C4 isozyme ranges from highly anodal in some species to slightly cathodal in others while the mobilities of the A4 and B4 tetramers remain relatively constant. Most fish species express the A and B genes for LDH in nearly all tissues. In contrast, the C gene is highly restricted in tissue expression in most advanced teleosts where its isozymic products are found predominantly in the eye of some species or in the liver of others.
Adrenocorticosteroid levels in adult Diemictylus viridescens plasma following hypophysectomy and forelimb amputation
Authors: Liversage Richard A. , Price Brian W.
Published: June 2005

The relative levels of plasma adrenocorticosteroids in control regenerate, sham hypophysectomized and hypophysectomized adult male and female Diemictylus viridescens (common newt) were measured ten days after forelimb amputation and compared with those of intact animals.

Our data provide evidence for an anterior pituitary‐adrenocortical axis in this urodele since hypophysectomy was followed by an appreciable decrease in the levels of plasma corticoids (corticosterone + cortisol) compared to control, sham and intact newts. The data also indicate that plasma adrenocorticos‐teroids are not abolished ten days post‐hypophysectomy. Corticosterone is the major adrenocortical steroid hormone in the plasma of this species.

In the presence of markedly reduced titres of adrenocorticosteroids, our experimental newts were in an abnormal physiological state and exhibited typical non‐regenerating forelimbs ten days after concomitant hypophysectomy and amputation.
Functional development of the hypothalamo‐hypophyseal‐adrenal cortex axis in the chick embryo, Gallus domesticus
Authors: Wise Phyllis M. , Frye B. E.
Published: June 2005

Basal plasma levels of corticosterone increased gradually during the second half of incubation, reaching a peak around the time of hatching. Stress resulted in a very significant elevation of corticosterone above the basal level in embryos 16 days or older, but not in younger embryos. Newly hatched chicks did not respond to stress, but a typical stress response was evident one week after hatching. Adrenocorticotropin (100 mU) elicited a significant rise in plasma corticosterone in 14‐day embryos and in newly hatched chicks, demonstrating that the adrenal is capable of responding to pituitary stimulation at these times when a stress response does not occur.

Decapitated 16‐day embryos had significantly lower basal levels of corticosterone than normal, and showed no rise in corticosterone in response to stress. Basal levels of corticosterone were unaffected by decapitation of 14‐day embryos. Grafting ten‐day embryonic pituitaries to the chorioallantoic membrane on day 9 of incubation restored normal basal hormone levels on day 16 in decapitated embryos, but did not restore the ability to respond to stress.

This study demonstrates that the hypothalamo‐hypophyseal‐adrenal axis is functional before hatching in chicks. The adrenal exhibits significant autonomous functional capability prior to day 14, and the pituitary becomes important in maintaining both the resting level of hormone and the stress response between days 14 and 16 of incubation. The hypothalamus does not appear to control normal resting levels of corticosterone, but is essential for the stress response.
Studies on hydra cells in vitro
Authors: Trenkner Ekkhart , Flick Kristine , Hansmann Gerald , Bode Hans , Bode Patricia
Published: June 2005

Methods for the disaggregation of hydra and maintenance of hydra cells are described. The cells synthesize DNA, RNA and Protein linearly for about 16 to 24 hours. DNA synthesized by cells in vitro has the same buoyant density in CsCl as DNA synthesized in the animal. The size distribution and processing of RNA synthesized in cultured cells is similar to that in the whole animal. Conversion of large RNA molecules to 28S and 18S rRNA species occurs in cultured cells. Interstitial cells committed to nematoblast differentiation complete development of the nematocyst in vitro.
Effect of pinealectomy and photoperiodism in the reproduction of indian weaver birds, Ploceus philippinus
Authors: Balasubramanian K. S. , Saxena R. N.
Published: June 2005

Indian weaver birds, Ploceus philippinus, are seasonal breeders and breed during June to August. Exposure of the adult male birds to long photoperiod (18L‐6D) during their nonbreeding period (November‐December), causes gonadal development and external changes (plumage and bill colour) characteristic of the breeding season, to occur a few months earlier than normal. Pinealectomy in winter also caused precocious sexual recrudescence. A combination of pinealectomy and long photoperiod accelerated the onset of the reproductive state more than either treatment alone. A short photoperiod (9L‐15D) which is normally nonstimulatory becomes stimulatory in pinealectomised birds which go into the breeding phase under this photoperiod within a few months of constant exposure.

In the juvenile birds, which normally start breeding in the second year of life, precocious gonadal development and breeding can be induced by exposure to long day length and/or pinealectomy when they are only one year old. It seems that pineal in these birds inhibits early gonadal growth in the adults and delays the onset of puberty in juveniles under natural day length.
Lens differentiation from the cornea following lens extirpation or cornea transplantation in Xenopus laevis
Authors: Waggoner Phillip R.
Published: June 2005

Larvae of Xenopus laevis at stage 46 or 50 were lentectomized and then fixed at various time intervals after the operation. Serial sections through the eye region were stained with hematoxylin and eosin or by the Himes‐Moriber technique to follow the histological changes taking place and to demonstrate any alterations in the basement membrane of the outer cornea. Lenses were observed to regenerate from the outer cornea while the basement membrane contributed to the capsule of the developing lens. A small lens with primary and secondary fibers was usually present by ten days after lentectomy.

Corneas of Xenopus laevis larvae were implanted into lentectomized eyes, dorsal fins, amputated hindlimbs or subcutaneously in the head region. Lenses formed from the implants in the lentectomized eyes and in the amputated hind‐limbs, but no lenses developed in the dorsal fins or from the subcutaneous implants. It is hypothesized that some conditions in the environment of the lentectomized eye and the amputated hindlimb may be similar.
Aspects of adrenal function in neonatally estrogenized male mice
Authors: Simmons J. Emmett , DiClementi David , Maxted George
Published: June 2005

Neonatal injection (day 5) of male CF1 mice with 50 μg of estradiol undecylate resulted in decreased body and testes weight and adrenal hypertrophy when these animals were examined at 95 days of age. The adrenal hypertrophy was associated with an increase in adrenal total cholesterol and plasma corticosterone after maximal ACTH stimulation. Orchiectomy of estradiol‐injected or oil‐injected control males did not significantly modify their response to ACTH stimulation. It is concluded that neonatal estrogenization of male mice causes, in addition to previously reported defects in subsequent reproductive function, long‐lasting changes in adrenal function.
Changes in liver metabolites during forelimb regeneration in the adult newt, D. viridescens
Authors: Procaccini Donald J. , Doyle Catherine M. , Procaccini Robert L.
Published: June 2005

Quantitative extraction, histological, and histochemical procedures were used to investigate the effects of the stress of forelimb amputation on liver metabolites in the adult newt, D. viridescens. Results of these experiments showed that hepatic PAS responsive stores were depleted two hours through one week after amputation while protein decreased 24 hours — one week after amputation. There was no change in hepatic lipid. Hepatic GLU 6‐PDH and α‐glucan phosphorylase activities increased almost immediately after limb amputation and did not return to normal until one week and two weeks later, respectively. These and previous experiments suggest a systemic response to forelimb amputation whereby liver metabolites may initially provide energy reserves for escape and survival and then contribute to the early phases of regeneration.
Tissue distribution and properties of the lactate and supernatant Malate dehydrogenase isozymes of the grayling, Thymallus arcticus (Pallas)
Authors: Massaro Edward J.
Published: June 2005

By gel exclusion chromatography the molecular weight of T. arcticus LDH was estimated to be 135,000–140,000 and that of MDH to be 65,000–70,000. Employing electrophoretic mobility in starch gel, molecular hybridization, and immunoprecipitation, the LDH isozymes could be classified into three major groups designated a, b and c and a minor group designated β. The c group was found exclusively in the eye. All tissues examined contained a, b and c group isozymes. The interaction of skeletal muscle a‐group isozymes with rabbit anti‐weak fish (Cynoscion regalis) A4 LDH antiserum was weak and, therefore, similar to that of the group of isozymes of Prosobium cylindraceum previously designated f (Massaro, '72). Starch gel electrophoresis at pH 8.6 resolved three major isozymes of supernatant MDH. In skeletal muscle, two additional minor, weakly detectable isozymes were observed. These exhibited a greater net negative charge than the major isozymes and may be conformational isozymes.
Studies on differentiation of Müllerian ducts in the quail, Coturnix coturnix japonica. I. Collagen synthesis during duct differentiation
Authors: Yamamoto Masamichi , Koshihara Hidetoshi , Noumura Tetsuo
Published: June 2005

Present investigations were carried out in an effort to determine the mechanisms in avian Müllerian duct differentiation, especially those responsible for the asymmetrical differentiation in female embryos. Ultra‐structural study of events during quail development demonstrated the following: At an early embryonic stage, a central simple‐layered epithelial canal was thickly enclosed with loose connective tissue whose fibroblasts resided in interlacing feeble networks. These fibroblasts appeared to migrate easily while maintaining tenuous contacts by slender cytoplasmic processes. At later stages, the loose connective tissue became denser and more concentrated near the canal. Fixed fibroblasts were surrounded by bundles of self‐elaborated collagen fibers completing a tight commissure with the basement membrane of the epithelium in the left duct, but a tight commissure was not completed in the rudimentary right duct.

Corresponding to ultramicroscopical features, collagen synthesis was estimated by 3H‐proline incorporation to be comparable to the 14C‐amino acids incorporated during duct differentiation. Specific activities revealed an apparent asymmetrical differentiation between the left and right ducts at an early embryonic stage when differences between both the ducts could hardly be discerned by electron microscopy. These incorporations in vitro were affected by the presence of estradiol at physiological concentrations and, indeed, exhibited certain differences between the left and right ducts in response to the presence of estradiol.
Testicular metamorphosis and prolongation of spermatogenesis in starlings (Sturnus vulgaris) in the absence of daily photostimulation
Authors: Rutledge James T. , Schwab Robert G.
Published: June 2005

Male European starlings (Sturnus vulgaris) were held in constant darkness for 448 days. Testicular widths, measured in situ via unilateral laparotomy at two to four week intervals, revealed that testicular growth reached a size associated with spermatogenesis in an average of 101 days. The spermatogenic period persisted for an average of 296 days. Histological examination of testes from two birds after 280 days of treatment revealed mature sperm in the seminiferous tubules. Complete testicular involution did not occur. Current photoperiodic theory must be modified to explain testicular metamorphosis without daily photostimulation in an avian species known to be photoperiodic.
The fine structure of regenerating notochord in anuran tadpoles
Authors: Overton Jane , Mapp Frederick E.
Published: June 2005

Because normal growth as well as successful regeneration of the anuran tadpole tail depend upon outgrowth of the notochord, this process has been studied at the fine structure level to determine the mode of elongation of the regenerating notochord. The present work shows that in Rana pipiens cells at the apical region of the notochord send out numerous filopodia containing microtubules and microfibrils which may align with or attach to fibrillar bundles in the matrix of the fin. These apical cells adhere to each other at “primitive attachment sites” whereas the notochord cells at more anterior levels adhere more closely and show other specialized attachments; desmosomes, intermediate junctions and junctions of the gap or nexus type. A basement membrane is present near the tip, but is not continuous over the apical region. These findings suggest cell motility at the apex and possibly guidance by the fibrillar elements of the matrix. Therefore, the collagen fibers of the fin were examined by light microscopy after a number of fixation and staining procedures. No clearcut evidence of a regular antero‐posterior orientation of fibrils in the matrix of the fin which could guide outgrowth was found. Results are considered in connection with experiments on notochord regeneration.