bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of haploid cell content of parthenogenetic turkey embryos: A cytofluorometric study
Authors: Deford Linda S. , Buss Edward G. , Todd Paul , Wood James C. S. 
Published: June 2005

AbstractA quantitative cytofluorometric study was undertaken to test the proposition that parthenogenetic development in turkeys begins in a haploid cell and proceeds toward the development of a completely diploid embryo. Embryo cell suspensions were obtained from eggs laid by virgin Beltsville Small White (BSW) turkey hens, and the cells from individual embryos were fluorescently stained with acriflavine, which is specific for DNA. The fluorescent emissions from individual cell nuclei were analyzed on a modified Bio/Physics Cytofluorograf, Model 6300A, and DNA distributions were obtained by analyzing nearly all of the cells in embryos ranging in age from five to nine days. These distributions were compared by computer analysis to the DNA distribution of a normally produced embryo. The DNA distributions revealed that many embryos contained large proportions of haploid cells and other abnormal cells. This study of haploid cells lends further support to the proposition that parthenogenesis in turkeys originates in a haploid egg cell, and diploidization observed in embryos occurs after meiosis. It was also shown that proportions of haploid and other non‐diploid cells declined with increasing embryo age.
Mechanisms of the compensation of blood respiratory acid‐base disturbances in the shore crab, Carcinus maenas (L.)
Authors: Truchot J. ‐P. 
Published: June 2005

AbstractApparent exchange of base with the external water was measured in crabs under various experimental conditions where compensation of blood respiratory acid‐base disturbances is known to occur. Crabs reimmersed after a long emersion time, or returned to normal conditions after hyperoxic or hypercapnic exposure, or loaded with sodium bicarbonate, apparently excrete a significant amount of an unidentified base to the external water. Conversely, an apparent acid output occurs during the first hours of an hyperoxic or hypercapnic treatment. As demonstrated by significant changes of the titration alkalinity of the respired water, the site of these exchange processes appears to be mainly the gills. Antennal gland excretion seems of minor importance as shown by obstructing the urinary pores or measuring urine acid‐base parameters. It is also inferred that exchange mechanisms between the cells and the extracellular fluid are also involved in the compensation of blood respiratory acidbase disturbances.
Neural regulation of cholinesterase in newt skeletal muscle. III. Regulation in vitro by proteins from chick embryo brains
Authors: Rathbone Michel P. , Vickers John D. , Logan David M. 
Published: June 2005

AbstractTriceps muscles of newts (Notophthalmus viridescens) lose AChE activity and show characteristic changes of various molecular forms of AChE after denervation in vivo or when maintained in organ culture (Rathbone et al., '79b). We examined the ability of nerve explants or homogenates from various sources to prevent the changes in total activity and molecular forms of AChE when added to the cultured muscles. These included dorsal root (sensory) ganglia from larval and adult Ambystoma tigrinum, from Plethodon cinereus and from chick embryo (10‐20 days in ovo). Sympathetic ganglia and brain homogenates offered the best combination of AChE‐maintaining activity and ready availability as a source from which to purify the active factor(s). The extracts of chick embryo brains (CBE) when added to newt triceps in organ culture both maintained total AChE activity and prevented alterations in the activity of the various molecular forms of AChE that normally occur after denervation or in organ culture. The active factor(s) were heat labile, trypsin sensitive but RNAase insensitive and had an apparent molecular weight of <20,000 daltons. Nerve growth factor, bovine serum albumin and RNA from chick embryo brains were all ineffective in maintaining the AChE activity of the muscles. The brain extracts also contained material of molecular weight >50,000 daltons that enhanced the loss of AChE from the muscles.It is concluded that embryonic chick brain extract is a plentiful source of neurotrophically active material from which a factor, most likely a small protein, can be purified for examination of the physiological role of putative neurotrophic factor.
Evolution of patterns of differential gene expression: A comparison of the temporal and spatial patterns of lsozyme locus expression in two closely related fish species (northern largemouth bass, Micropterus salmoides salmoides, and Smallmouth Bass, Micropterus dolomieui)
Authors: Philipp David P. , Childers William F. , Whitt Gregory S. 
Published: June 2005

AbstractThe timing of the onset of developmental expression of 33 loci encoding various enzymes and isozymes was determined for two closely related species of fish, the northern largemouth bass, Micropterus salmoides salmoides, and the smallmouth bass, M. dolomieui. The patterns of gene expression among the different tissues in adults were also investigated. The tissue and developmental expressions of these enzymes and isozymes were visualized by histochemical staining after starch gel electrophoresis. The differential expression of homologous loci within and among the different adult tissues of these two related species is virtually identical. The ontogenetic times of expression during the embryogenesis of both species are also quite similar for these same homologous loci. The ontogenetic patterns of differential gene expression for these two species differ somewhat from those of a more distantly related species within the family Centrarchidae, the green sunfish, Lepomis cyanellus. These results are consistent with the hypothesis that there is an increase in divergence of gene expression in species which are progressively more distantly related.
Genetics of the malate dehydrogenase isozymes of the isopod porcellio scaber
Authors: Sassaman Clay 
Published: June 2005

AbstractElectrophoretic analysis of malate dehydrogenase (MDH) in extracts of the isopod Porcellio scaber Latr. indicates two zones of activity, MDH‐1 and MDH‐2, corresponding to the cytoplasmic and mitochondrial forms respectively. Electrophoretic variants of both forms have been isolated from natural populations. The locus encoding MDH‐1 has at least three alleles in appreciable frequency; the MDH‐2 locus has two. Breeding studies indicate that variants of both forms of MDH have Mendelian inheritance patterns, and that the two proteins are encoded by independently assorting autosomal genes. Neither MDH gene is apparently linked to the autosomal gene which encodes phosphoglucose isomerase.
Changes observed in bone during hibernation using procion red dye as a matrical marker
Authors: Steinberg Barry , Singh Inder Jit , Mitchell Ormond G. 
Published: June 2005

AbstractVisual examination of the intensity of Procion dye in hamster femurs revealed that dye incorporation decreased during hibernation. Little or no dye was observed after hibernation lasting longer than 50 days. It seems that hibernation may be associated with increased bone resorption and a loss of bone matrix.
Ultrastructure of blastocoel material in blastulae and gastrulae of the sea urchin Lytechinus pictus
Authors: Katow Hideki , Solursh Michael 
Published: June 2005

AbstractThe ultrastructure of blastocoelic material in blastulae and gastrulae of the sea urchin Lytechinus pictus was revealed by transmission and scanning electron microscopy.The blastocoel of blastulae contained 30 nm diameter granules, aggregated in long chains. In gastrulae, on the other hand, another component was present: fine fibers. The 30 nm granules were attached to the surface of these fine fibers to form a thicker, rough‐surfaced complex fibrous structure.Embryos cultured in sulfate deficient sea water had greatly reduced numbers of 30 nm granules in the blastocoel. The fine fibers appeared normal. Consequently, the 30 nm granules are selectively sensitive to sulfate deprivation.
Developmental physiology of cestodes. XV. A system for testing possible crowding factors in vitro
Authors: Insler Gayle Dranch , Roberts Larry S. 
Published: June 2005

AbstractIt has been long known that Hymenolepis diminuta (Cestoda: Cyclophyllidea) exhibits a crowding effect when developing in its definitive host, the rat. Experiments were designed to test whether the worms might secrete substances inhibitory to the growth of other worms, thus helping to account for the crowding effect. A worm conditioned saline (WCS) was prepared by incubation of 10‐day‐old worms from crowded infections in a balanced salt solution, then testing the effect of the WCS on the incorporation of 3H‐thymidine into the DNA of other worms from uncrowded infections. Incorporation of 3H‐thymidine into the DNA of the anterior regions of the test worms was inhibited by about 50–60% compared to controls. Incubation in WCS also inhibited incorporation of 3H‐uridine and 3H‐mino acids into RNA and protein, respectively, of the test worms. These responses are similar to those previously observed in crowded worms. The inhibition was apparently not a cytotoxic, phenomenon since the effect was reversible, the energy charge of worms incubated in WCS was the same as that of controls, and the tegument of incubated worms was intact.
Developmental physiology of cestodes XVI. Effects of certain excretory products on incorporation of 3H‐thymidine into DNA of Hymenolepis diminuta
Authors: Insler Gayle Dranch , Roberts Larry S. 
Published: June 2005

AbstractSuccinate and acetate, which are excreted by Hymenolepis diminuta (Cestoda: Cyclophyllidea), account for about half the inhibition of DNA synthesis observed when the worms are incubated in a “worm conditioned saline” (WCS). Succinate is probably responsible for the bulk of the inhibition, while lactate, which is also excreted by the worms, is inactive. Ammonia and urea at concentrations present in the WCS do not inhibit incorporation of thymidine into DNA. Incubation in WCS or 12 mM succinate, for more than 1 hr inhibits glucose uptake by the worms, but the effect is reversible; therefore, the inhibition is not a result of permanent damage. Concentrations of succinate found in WCS appear physiologic since they agree well with levels found in the small intestines of rats infected with high density populations of H. diminuta.
Neuromuscular mechanisms in the insect foregut
Authors: Yamamoto Daisuke , Fukami Jun‐Ichi 
Published: June 2005

AbstractBioelectric potentials were recorded intracellularly from the foregut muscle fibres of the larva of the waxmoth Gelleria mellonella.Myogenic spikes were generated spontaneously or by direct stimulation of the fibres of the crop, anterior and posterior proventriculus. The action potentials from these three regions were distinguishable from each other by their characteristic shapes and duration. Pacemaker potentials were recorded from fibres of the crop and the posterior proventriculus but not recorded from the anterior proventriculus, where only follower type potential changes could be observed.Spontaneous and evoked EJPs were obtained from the crop and the posterior proventriculus but were not recorded from the anterior proventriculus. The reversal potential for evoked EJPs was estimated at about 0 mV by a method of extrapolation.Chemical sensitivity of evoked EJPs was examined. Seven putative transmitters including acetylcholine, L‐glutamic acid, L‐aspertic acid, norepinephrine, octopamine, dopamine, and 5‐hydroxytryptamine were tested. It was found that L‐glutamic acid depressed EJP at about 10−4 M. Specific agonists and antagonists were also administered on EJPs. Effects of atropine, phentolamine, tyramine, and BOL‐148 were negligible and eserine and propranolol blocked transmission at 5 × 10−4 M. D‐tubocurarine (5 × 10−4 M) enhanced the EJP, with occasional exceptions. The actions of the last three drugs were, however, inconsistent, and were considered to be nonspecific. In contrast, kainic acid had consistent effects; potentiated EJPs at 2.5‐,5 × 10−5 M and blocked at 1 × 10−3 M. From these observations it was suspected that among seven compounds tested, L‐glutamic acid is the most probable candidate for a transmitter.The firing rhythm of myogenic spikes generating spontaneously could be reset by neurally evoked spikes.
Photoperiodic control of antler cycles in deer. V. Reversed seasons
Authors: Goss Richard J. 
Published: June 2005

AbstractNewborn and weanling fawns were held under reversed annual light cycles to learn if the subsequent replacement of their antlers would coincide with the anniversary of their births, as occurs in nature, or adapt to the artificial seasons of increasing day lengths even when these fall at the “wrong” time of year. The first sets of antlers developed at approximately the normal age when the deer were yearlings. These antlers, however, were shed and replaced half a year earlier than would otherwise haveoccurred under natural environmental conditions. It is concluded that the onset of renewed antler growth is not a response to every other time the photoperiod increases or decreases, but is triggered by lengthening days, irrespective of the age of the deer.
Studies on oocyte maturation of the medaka, Oryzias latipes. VIII. Role of follicular constituents in gonadotropin‐ and steroid‐induced maturation of oocytes in vitro
Authors: Iwamatsu Takashi 
Published: June 2005

AbstractParticipation of the follicular constituents in gonadotropin‐ and steroid‐induced maturation of Oryzias latipes oocytes was examined in vitro by removing these constituents and coculturing them with the denuded oocytes. Removal of all follicular constituents prevented gonadotropin‐induced maturation of oocytes, but the removal of the thecal cells and the basal lamina from the follicle did not prevent maturation. Moreover, the denuded oocytes did mature in the presence of gonadotropin when cocultured with granulosa cells previously separated from large preovulatory follicles or with postovulatory follicles. However, the denuded oocytes did not respond to gonadotropin by maturing when cocultured with either thecal cells and basal lamina of the, premature follicles or the granulosa cells of small follicles 22–24 hr before ovulation. These results indicate that the presence of the granulosa cells of large pre‐ and postovulatory follicles is important for gonadotropin‐induced oocyte maturation. The denuded oocytes, which were incapable of responding to gonadotropin, were stimulated by various steroids to undergo meiotic maturation. The concentrations of steroids effective in inducing maturation were lower for the denuded oocytes than for the oocytes within intact follicles or enveloped by granulosa cells alone.The present results suggest that the gonadotropin‐stimulated granulosa cells of both pre‐ and postovulatory follicles play a major role in inducing oocyte maturation through secretion of steroids in the circadian ovulatory cycle of Oryzias latipes.
Ribonucleosides bound to the major yolk components in eggs of the insects Euscelis and Smittia
Authors: Schmidt Otto , Jäckle Herbert 
Published: June 2005

AbstractThe uptake of radioactive RNA precursors into growing oocytes of insect ovaries was studied. In addition to incorporation of radioactivity into RNA, labelled nucleosides were also observed in the egg. Some of this radioactivity is bound covalently to yolk glycoproteins.
Insulin levels in the serum of intact and regenerating adult newts (Notophthalmus viridescens)
Authors: Liversage Richard A. , Banks Brian J. 
Published: June 2005

AbstractRadioimmunoassay (RIA) procedures were used to determine whether or not insulin is present in the adult newt. The results show that measurable amounts of the hormone are present in samples ofpooled, fresh serum taken by cardiac puncture methods. We also found that there are no significant changes in the level of insulin in regenerating newts compared with intact animals.
Melatonin inhibition of vasopressin‐stimulated water transport in the toad urinary bladder
Authors: Haswell M. Stephen , Gern William A. , Ralph Charles L. 
Published: June 2005

AbstractBecause melatonin mimics the effects of microtubular disruptive agents (e.g., colchicine) in various cellular systems, we have examined its effect on water transport in the toad urinary bladder. Microtubules are essential to vasopressin‐stimulated water transport in this tissue and are labile to colchicine (Kachadorian et al., '79). In unstimulated urinary bladders, melatonin is without effect; however, in the presence of 20 μ/ml of vasopressin, 4 × 10−6M melatonin significantly reduced the stimulation of water transport in this preparation. The inhibition of water transport by melatonin is comparable to that effected by colchicine. The possibility that melatonin may modulate microtubular functions is discussed.
Histological structure of epithelial hydra and evidence for the complete absence of interstitial and nerve cells
Authors: Wanek Nancy , Marcum Beverly A. , Campbell Richard D. 
Published: June 2005

AbstractHydra were treated with colchicine, resulting in the elimination of interstitial, nerve, and stinging cells. These animals were cloned for several months and then examined histologically to determine: (1) the extent of cell depletion, and (2) the effect of this depletion on tissue structure and epithelial cell morphology. Thirteen of these hydra were serially sectioned for light microscopy and every cell was identified. All of the animals were composed solely of epithelial cells. No cells of the interstitial cell lineage, which includes interstitial cells, nerve cells, nematoblasts, and gametes, were found. Using experimental hydra with low numbers of interstitial and nerve cells, we verified that these cell types, when present, are readily identifiable in histological sections. Thus, we conclude that the cloned hydra are completely free of all cells except epithelial cells, and hence are defined as epithelial hydra. The histological organization of epithelial cells is normal in these animals. In each body region (hypostome, tentacles, gastricregion, peduncle, and basal disc) the organization of tissue and epithelial cell structure is normal. Therefore, epithelial cells are capable of autonomous region‐specific differentiations, and tissue architecture can arise independently of the interstitial cell lineage.
Limiting conditions for conjugation in Tetrahymena: Cellular development and factor active in conjugation
Authors: Wolfe Jason , Meal Katharine J. , Soiffer Robert 
Published: June 2005

AbstractConjugation in Tetrahymena thermophila is a three component system requiring starved cells of two complementary mating types and an extracellular macromolecular factor active in conjugation (FAC). Because the rate of cell pairing is related to the concentration of FAC in the extracellular medium, an assay for FAC was developed using standard test cells. The rate of release of FAC into the medium was measured in cells transferred from growth medium. It was found that a) FAC production is rapid, being detectable within 15 min after shift down; b) within 1 hr, sufficient FAC is released by the cells to support near maximal pairing activity among test cells; and c) cycloheximide completely blocks release of FAC. It was further demonstrated that addition of high‐titer FAC to freshly shifted down cells did not shorten the delay period before conjugation. Therefore, the starvation period is a time during which a) FAC is released into the medium, and b) cells develop receptivity to mating interactions, with the latter being rate‐limiting for conjugation. FAC is produced by sexually immature cells, by cells in growth medium, and by cells starving in high ionic strength buffer, but not by nonmating amicronucleate cells of T. pyriformis. Cell interactions during mating are modulated by FAC, but only among developmentally receptive cells.
Surgical removal of the olfactory bulbs increases sensitivity of the reproductive system of female rats to the inhibitory effects of late afternoon melatonin injections
Authors: Reiter Russel J. , Petterborg Larry J. , Trakulrungsi Chatchai , Trakulrungsi Wantanee K. 
Published: June 2005

AbstractIn rats, anosmia induced by olfactory bulbectomy sensitizes the neuroendocrine‐reproductive axis to the inhibitory effects of the pineal gland. Thus, combined blinding (which stimulates pineal antigonadotrophic activity) and anosmia cause a marked delay in the sexual maturation of female rats. The present study tested whether anosmia would also sensitize the neuroendocrine axis to the reproductive inhibitory effects of melatonin. In the present study, young female rats were rendered anosmic and maintained under light:dark cycles of 14:10; they were given melatonin injections daily (25 μg) at either 0900 hr (AM‐melatonin) or at 1800 hr (PM‐melatonin)—i.e., either 3 or 12 hr after lights on, respectively. The melatonin injections were begun when the rats were 23 days of age and were continued for 35 days. By comparison with AM‐melatonin, PM‐melatonin injections were considerably more effective in inhibiting bodily growth as well as the weights of the anterior pituitary, ovaries, and uterus of anosmic rats. Similarly, the changes in pituitary and plasma LH and PRL levels were more obvious in the PM‐treated anosmic rats than in those given melatonin in the morning. Thus, anosmia does increase the sensitivity of the neuroendocrine‐reproductive axis to melatonin, provided the indoleamine is administered late in the light phase of the light:dark cycle. Anosmia by itself had no influence on the daytime levels of radioimmunoassayable melatonin within the pineal gland, whereas in blinded control rats, melatonin levels were markedly augmented.
The transport of L‐alanine by the integument of the marine polychaete, Glycera dibranchiata
Authors: Stevens Bruce R. , Preston Robert L. 
Published: June 2005

AbstractThe unidirectional influx of14C‐L‐alanine into the external integument surface of Glycera dibranchiata was measured in the presence and absence of sodium using lucite influx chambers which permitted brief exposures of only the external surface of the body wall to isotope. The influx of alanine was the sum of a mediated component obligatorily dependent on sodium in the external medium, and a nonsaturable sodium‐independent diffusion component. The mediated component was inhibitable by other amino acids, lacked transconcentration effects, and had a Q10 of 9.64 near the acclimation temperature of 12°C. The diffusion component was not competitively inhibitable and had a Q10 of 0.99 at 12°C. The saturable component had a Kt = 8.63 × 10−5 M and Jmax = 1.38 × 10−7 mol/hr · cm2. The Kt falls within the physiological range of free amino acid concentrations to which the worm would be exposed in its habitat.
The effect of sodium on the kinetics of L‐alanine influx by the integument of the marine polychaete, Glycera dibranchiata
Authors: Stevens Bruce R. , Preston Robert L. 
Published: June 2005

AbstractThe kinetics of sodium‐dependent L‐(U‐14C)alanine influx into the integument of Glycera dibranchiata were studied in vitro utilizing lucite influx chambers. Glycera integument accumulated alanine via two distinct sodiumcoupled carrier mediated systems which are described by similar kinetic equations. The coupling coefficient determined by graphical analysis was equal to 3 for each influx system. Both systems share a common Kt = 8.6 × 10−5 M alanine which was not affected by sodium concentration. However, each system possessed dissimilar maximal influx values that were sensitive to sodium concentration. A model is presented describing the molecular events of sodium‐coupled alanine transport by the integumentary epithelial cell membrane of Glycera.