bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitotic behavior and pseudopodial activity of cells in the embryo of Oryzias latipes during blastula and gastrula stages
Authors: Kageyama T. 
Published: June 2005

AbstractA simple and rapid method for mechanically isolating cells from fixed embryos of Oryzias latipes was developed, in order to study the mitotic and pseudopodial activities of the cells during early development. Most of the sister cells retain cytoplasmic connections with each other until the prophase of the next mitosis, during the synchronous cleavage stage. The cells of the enveloping layer (EVL), an embryonic epithelium, never extrude pseudopodia. The appearance and the increase and decrease of six types of pseudopodial activity in deep cells during the blastula and gastrula stages are described, and an antagonism between the mitotic and the pseudopodial activities in deep cells has been documented in a quantitative manner. A noteworthy finding in the present study is the occurrence of an elongated intercellular cytoplasmic bridge, which connects members of pairs of postmitotic deep cells from the midblastula stage until the late gastrula stage. The intercellular bridge has been found for the first time in the Oryzias embryo as a result of the newly developed method for the isolation of cells.
Oocyte activation in the marine shrimp, Sicyonia ingentis
Authors: Pillai Muralidharan C. , Clark Wallis H. 
Published: June 2005

AbstractThe resumption of meiotic maturation and formation of the hatching envelope in the ova of the marine shrimp, Sicyonia ingentis were triggered by exposure to seawater. Fertilized and unfertilized ova underwent the same sequence of events; however, a slightly longer time was required for the completion of meiotic maturation and hatching envelope formation in unfertilized ova. The hatching envelopes formed in both cases were structually identical. Activation of unfertilized ova, but not fertilized ova, depended on external Ca++. If unfertilized ova that formed neither polar bodies nor a hatching envelope in Ca++‐free seawater were transferred to normal seawater, activation resumed. External Mg++ was necessary for both fertilized and unfertilized ova to undergo activation.
Coexpression of distinct eye‐ and liver‐specific LDH isozymes in cichlid fish
Authors: Holt Robert W. , Leibel Wayne S. 
Published: June 2005

AbstractIn a recent electrophoretic survey of lactate dehydrogenase (LDH) in neotropical cichlid fishes (Perciformes, Cichlidae) we have discovered several species in which a cathodal liver‐specific isozyme is expressed along with the highly‐anodal eye‐specific isozyme (LDH‐C4) typically encountered in perciform fishes. We believe this fourth, liver‐specific LDH isozyme to be real and not artifactual since homogenization of fresh liver from one of these species, the Basketmouth cichlid (Acaronia nassa), in either of two nondenaturing detergents or in the presence of the protease inhibitor phenylmethylsulfonylfluoride affects neither the presence nor mobility of this cathodal band. Moreover, it continues to be expressed in the captively bred F1 of these same wild fish.The discovery of several fish species, like the Basketmouth, in which biochemically distinct eye‐ and liver‐specific LDH isozymes are coexpressed, is discussed in light of the currently accepted hypothesis that these two isozymes are encoded by a single locus (LDH‐C) which has undergone divergent tissue expression in several other major teleost groups. Preliminary characterization of the liver‐specific isozyme relative to the eye‐specific LDH‐C4 in the Basketmouth cichlid with respect to thermolability and NADH‐induced binding to oxamate‐sepharose columns suggests that the eye‐ and liver‐specific LDH isozymes are biochemically quite distinct in this fish and that they are probably encoded by two distinct loci.
Water balance responses of the hylid frog Litoria aurea
Authors: Cree Alison 
Published: June 2005

AbstractCutaneous and antidiuretic water balance responses of the hylid frog Litoria aurea to dehydration and exogenous arginine vasotocin (AVT) were examined. Both dehydration and AVT caused an increase in the rate of water uptake through ventral skin. Dehydration (in one of two experiments) and AVT also caused a reduction in the rate of bladder urine accumulation. During rehydration, rates of water uptake through ventral skin were seven times higher than through the average body surface of immersed frogs. Treatment of normally hydrated frogs with AVT in vivo caused increased cutaneous water uptake and a reduction in glomerular filtration rate; together these produced water retention equivalent to 27% above original body weight. Pelvic skin had a higher resting rate of osmotic water flow (OWF) in vitro than did pectoral or dorsal skin and was the only region to show increased OWF in response to AVT. The cutaneous hydroosmotic response of L. aurea to AVT is unusually large for a semiaquatic frog, and this may reflect the basking habits of this species or its position within the Hylidae.
Differential effects of testosterone and dibutyryl cyclic AMP on the meiotic maturation of mouse oocytes in vitro
Authors: Ecay Tom W. , Powers R. Douglas 
Published: June 2005

AbstractFully grown, meiotically immature mouse oocytes were isolated and cultured under varying conditions with the aim of determining a) whether the inhibitory effects of testosterone on oocyte meiotic maturation require the synthesis of new oocyte proteins and b) if the meiosis‐inhibiting effects of testosterone and dibutyryl cyclic AMP (dbcAMP) are distinct and can be differentiated. We found that the inclusion of puromycin in culture medium containing testosterone has no effect on the meiosis‐inhibiting potency of testosterone or upon the reversibility of testosterone effects. We conclude that testosterone inhibits oocyte meiosis by a mechanism that is independent of protein synthesis. We also found that oocytes exposed to testosterone recover more rapidly, as evidenced by the timing of germinal vesicle breakdown (GVBD) following placement in a control medium, than do oocytes exposed to dbcAMP. Through further investigation of this phenomenon we have determined the sequence of testosterone and dbcAMP effects relative to the time course of GVBD. A testosterone‐sensitive event occurs 20 min prior to GVBD, while the dbcAMP‐sensitive event precedes GVBD by 41 min. The nature of this difference may involve the differential interaction of testosterone and dbcAMP with a set of puromycin‐sensitive proteins that are required for GVBD. When oocytes were initially cultured in medium containing both puromycin and either testosterone or dbcAMP and then moved to medium containing puromycin alone the incidence of GVBD was reduced relative to oocytes never exposed to puromycin. This observation suggests that mouse oocytes contain proteins that are required for GVBD and that experience a high turnover rate. The degree of reduction in GVBD was a function of the length of puromycin exposure and was significantly greater in dbcAMP‐ than in testosterone‐exposed oocytes. If oocytes were initially cultured in medium containing puromycin and dbcAMP, the rate of GVBD upon removal of dbcAMP was initially slow but increased with time. This observation is consistent with the hypothesis that dbcAMP inhibits oocytes at a point prior to the functioning of the puromycin‐sensitive proteins. However, if oocytes were cultured in medium containing puromycin and testosterone the rate of GVBD following testosterone removal was not significantly reduced relative to oocytes that were not exposed to puromycin. This observation suggests that testosterone acts to inhibit meiosis at a site beyond the function of the puromycin‐sensitive proteins or that testosterone causes a reduction in the turnover rate of these proteins. We conclude that the effects of testosterone and dbcAMP on the mouse oocytes are distinct and distinguishable and further that testosterone will be a useful tool in dissecting the molecular mechanisms controlling mouse oocyte meiotic maturation.
An in situ measurement of sperm dispersal in a colonial marine hydroid
Authors: Yund Philip O. 
Published: June 2005

AbstractBecause gamete dispersal in the water column is an essential feature of sexual reproduction in most sessile invertebrates, an analysis of gamete dispersal patterns in the field is vital to an understanding of gene flow in these organisms. This paper presents the results of an in situ measurement of sperm dispersal in the colonial hydroid Hydractinia echinata conducted in calm water. The environmental cue mediating gamete release (exposure to light) was manipulated to temporally isolate experimental animals from the natural population. As assayed by the development of eggs collected at various distances from a male colony, the fertilization rate was very high within 3 m but dropped off rapidly with no fertilization observed beyond 7 m. The short sperm dispersal distances reported here, combined with a general trend toward larval dispersal distances on a similar spatial scale, suggest that gene flow in colonial invertebrates occurs on a relatively small spatial scale.
Humoral response of the snail Biomphalaria glabrata to trematode infection: Observations on a circulating hemagglutinin
Authors: Couch Lee , Hertel Lynn A. , Loker Eric S. 
Published: June 2005

AbstractThe hemolymph of invertebrates often contains molecules that agglutinate vertebrate erythrocytes and that may function as humoral mediators of “non‐self” recognition. The objectives of this study were to 1) determine if exposure of M line or 10‐R2 strain Biomphalaria glabrata snails to infection with the trematodes Echinostoma paraensei and Schistosoma mansoni could increase agglutinating activity in snail hemolymph, and 2) identify particular hemolymph molecules with such activity. In some host‐parasite combinations, such as juvenile M line snails and E. paraensei, infection provoked significant elevations in titer from as early as 2 days post‐infection (dpi) through 15 dpi. In other combinations, as with 10‐R2 snails and E. paraensei or S. mansoni, host responses were comparatively modest, yet still measurable. In general, E. paraensei and S. mansoni elicited different responses from the same host strain, and M line and 10‐R2 snails responded differently to the same parasite. Further study of the response of juvenile M line snails to E. paraensei indicated that hemolymph agglutinating activity could be inhibited by several monosaccharides (including L‐fucose) and by EDTA and EGTA. An affinity column containing L‐fucose agarose beads was used to purify molecules with agglutinating activity from the hemolymph of such snails. The fraction eluted from the column by 0.2 M L‐fucose was shown by SDS‐PAGE to contain a broad band of 80–120 kD and, less consistently, a 200 kD band. Following extensive dialysis to remove L‐fucose, this fraction had agglutinating activity. As a previous study has shown that the hemolymph of E. paraensei–infected snails contains significantly increased quantities of 80–120 kD polypeptides, it is concluded that polypeptides in this size range are responsible, at least in part, for the increased hemolymph agglutination activity in such snails.
Effect of noradrenaline on the methaemoglobin concentration of rainbow trout red cells
Authors: Paajaste Marita , Nikinmaa Mikko 
Published: June 2005

AbstractWe studied the effect of noradrenaline on the methaemoglobin (metHb) concentration in rainbow trout red cells. The erythrocytes were incubated in physiological medium with or without noradrenaline and the percentage of metHb of total Hb content was measured. Noradrenaline lowered the metHb content significantly as compared to controls. To study if the effect of noradrenaline was caused by adrenergic intracellular alkalinization, cells were treated with noradrenaline + carbonic anhydrase or noradrenaline + acetazolamide. Carbonic anhydrase inhibits the adrenergic increase in intracellular pH, but did not reduce the effect of noradrenaline on the metHb concentration. Acetazolamide accentuates the increase in intracellular pH. However, there was no difference in the methaemoglobin content of noradrenaline‐incubated and noradrenaline + acetazolamide‐incubated cells. These results show that the effect of noradrenaline on the methaemoglobin content is independent from the adrenergic increase in intracellular pH. However, amil‐oride treatment inhibited the effect of noradrenaline on the methaemoglobin content, suggesting that the protein mediating sodium/proton exchange may also be involved in controlling cellular methaemoglobin levels.
Sodium orthovanadate induces in vitro ovulation and ovarian prostaglandin synthesis in brook trout (Salvelinus fontinalis)
Authors: Hsu Sheau‐Yu , Goetz Frederick William 
Published: June 2005

AbstractThe in vitro effects of sodium orthovanadate (Na3VO4), a G‐protein activator, on ovulation and prostaglandin (PG) synthesis were investigated in the brook trout (Salvelinus fontinalis) ovary. PGE and PGF levels in incubation medium of either extrafollicular (EF) tissue or follicles were measured by specific radioimmunoassays (RIA). PGE levels in follicle incubates were increased by Na3VO4 at both pre‐germinal vesicle breakdown (preGVBD) and preovulatory (preOV) stages. However, an increase of PGF levels in follicle incubates was observed only in preGVBD follicles in the presence of Na3VO4. The preOV follicles spontaneously released more PGF than preGVBD follicles and the level was not affected by Na3VO4 treatment. In contrast, in incubates of EF tissue, Na3VO4 induced dosage‐dependent increases in PGE and PGF at either stage. The Na3VO4‐stimulated increase of PGE in preOV follicle incubates was significantly reduced by the translational inhibitor, cycloheximide (5 μM), but not by the transcriptional inhibitor, actinomycin (5 μM). PGF levels in preOV follicle incubates were also significantly reduced by cycloheximide and actinomycin in controls, but not in the presence of 0.1 mM Na3VO4. The results suggest that protein synthesis was required for Na3VO4 to increase accumulation of PGE, and in maintaining control PGF levels in preOV follicles. In addition, since PGF levels in preOV follicles were not reduced by either inhibitor in the presence of Na3VO4, a Na3VO4‐stimulated increase of PGF levels was unmasked that apparently acts through a non‐translational pathway. In vitro ovulation was also significantly increased by 0.1 mM Na3VO4. However, the Na3VO4‐induced ovulation was not inhibited by either actinomycin or cycloheximide. The data imply that the mechanism(s) by which Na3VO4 induces ovulation are distinct from that for stimulating PG accumulation. When preOV follicles were incubated with 10 μM forskolin, no stimulatory effect on ovulation, or on PGE and PGF levels was observed. The data strongly indicate that the effects of Na3VO4 on ovulation and ovarian PG levels were not mediated by an increase in cAMP.
Monoamines and neuropeptides as transmitters in the sedentary polychaete Sabellastarte magnifica: Actions on the longitudinal muscle of the body wall
Authors: Díaz‐Miranda Lucy , de Motta Gladys Escalona , García‐Arrarás José E. 
Published: June 2005

AbstractPharmacological studies on the body wall musculature of the sedentary polychaete Sabellastarte magnifica show a potential neurotransmitter role for monoamines and neuropeptides in this organism. All catecholamines induced contraction of longitudinal muscle strips, while serotonin and the neuropeptides FMRFamide and substance P caused a relaxation of both resting and active muscle. In addition, we demonstrate catecholaminergic and serotonergic pathways in the nervous system of this sabellid, using immunohistochemistry and catecholamine‐induced fluorescence. The presence of neuropeptide‐containing fibers in the nervous system of this polychaete has been previously reported. Together these results suggest that catecholamines act as excitatory transmitters on the longitudinal muscle cells of the body wall of S. magnifica, while serotonin and FMRFamide, and possible substance P, are inhibitory transmitters. The possibility of coexistence of serotonin and FMRFamide within the same neuronal cell bodies and fibers of this polychaete is also explored. © 1992 Wiley‐Liss, Inc.
Interactive effects of high stocking density and triiodothyronine‐administration on aspects of the in vivo intermediary metabolism and in vitro hepatic response to catecholamine and pancreatic hormone stimulation in brook charr, Salvelinus fontinalis
Authors: Scott‐Thomas D. A. F. , Ballantyne J. S. , Leatherland J. F. 
Published: June 2005

AbstractBrook charr (Salvelinus fontinalis) were maintained at one of two stocking densities (SD) (30 or 120 kg/m3) and fed either a control or a T3‐supplemented (20 mg/kg) diet for 30 days in order to investigate possible interactive effects of SD and T3‐administration on growth, feeding rate, food conversion efficiency, and hepatic and dark muscle enzyme activity. In addition, liver slices were incubated in vitro for 6 h with epinephrin, norepinephrin, isoproterenol, propranolol, insulin, glucagon, or somatostatin to evaluate possible SD‐T3 interactive effects on hepatic responses to hormonal stimulation. Maintaining the fish at high SD appeared to increase the clearance rate of T3 from the T3‐supplemented group. There was no clear evidence of SD‐T3 interactive effects on growth rate, feeding rate, or food conversion efficiency, although T3‐administration decreased food conversion efficiency, and high SD decreased growth and feeding rates. Of the hepatic enzymes studied, HOAD, malic enzyme, G6PDH, CS, PFK, HK, and GDH activities all showed changes suggestive of interactive SD‐T3 effects. Although hepatic FBPase was stimulated by both high SD and T3‐administration, there was no evidence of interactive SD‐T3 effects. Dark muscle HOAD, CS, and PFK also showed SD‐T3‐related responses; dark muscle malic enzyme, G6PDH, HK, and GDH were unaffected by either altered SD or T3‐administration.Prior treatment of the fish with T3 and high SD had significant effects on free fatty acid (ffa) release to the medium and on hepatic lipid content, but had no effect on the responses to the various endocrine agents used. Glucose release from liver slices of fish stocked at high density (both T3‐supplemented and controls) was higher than that of the fish stocked at low density; with the exception of insulin and glucagon, glucose release was similar in all pre‐treatment groups. The insulin‐ and glucagon‐stimulated changes in glucose release seen in the fish fed non‐supplemented diets were not found in the two groups of fish fed the T3‐supplemented diets. High SD and/or T3‐administration induced significant lowering of hepatic glycogen content, but there was no effect of pre‐treatment on the response to any of the endocrine agents used. The data show a marked effect of SD on energy partitioning processes in brook charr and the animal's ability to respond to T3‐stimulation, but provided no evidence of such effects on the liver response to the various agents used. © 1992 Wiley‐Liss, Inc.
Intrinsic pigment cell stimulating activity in the skin of the leopard frog, Rana pipiens
Authors: Mangano Francesco T. , Fukuzawa Toshihiko , Johnson Warren C. , Bagnara Joseph T. 
Published: June 2005

AbstractConsistent with the concept that specific pigment patterns of amphibians might result from the highly localized distribution of stimulators and inhibitors of pigment cell expression in the skin, the spot pattern of the leopard frog, Rana pipiens, was examined through the use of the Xenopus neural tube explant assay system (Fukuzawa and Ide, 1988). Media conditioned with pieces of skin from dorsal black spotted areas promoted melanization of neural crest cells at a significantly higher level than did media conditioned with dorsal interspot skin in the absence of extra tyrosine. All conditioned media contained exceedingly low concentrations of tyrosine. With the addition of supplemental tyrosine, the melanization capacity of conditioned media from the interspot areas was elevated to that of the spotted skin. Control media conditioned with ventral frog skin inhibited melanization, as usual, because of the presumed presence of melanization inhibiting factor (MIF). It is considered that dorsal skin contains a melanization stimulating factor (MSF) which is present in significantly higher levels in spotted skin than in interspot areas and that expression of the particular pigmentary pattern of this leopard frog is regulated by the relative distribution of MIF, MSF, and possibly other intrinsic substances present in the skin. © 1992 Wiley‐Liss, Inc.
Ontogeny of neurotransmitter systems: Substrates for developmental disabilities?
Authors: Lauder Jean M. 
Published: June 2005

AbstractThis papaer provides an overview of the developmental characteristics of several major CNS neurotransmitter systems, specifically those involving serotonin, catecholamines, and GABA. These were chosen because of their putative importance in various aspects of brain development or plasticity, and the existence of clinically relevant sequelae linking these systems to developmental disorders and disabilities. Patterns of development of these neurotransmitter systems and their putative roles as developmental signals are discussed, as is their possible relevance to developmental disabilities such as autism, attention‐deficit/hyperactivity disorders, self‐injurious behaviour, and epilepsy. © 1995 Wiley‐Liss, Inc.
Prenatal exposure to opiates
Authors: DeCristofaro Joseph D. , Lagamma Edmund F. 
Published: June 2005

AbstractOpiate use has been described for thousands of years. In this century, clinical features of the “neonatal abstinence syndrome” have been amply documented in the medical literature. Indeed, the abuse of “recreational” drugs continues at an alarming rate and results in a high number of adverse maternal‐fetal outcomes even as we near the end of the twentieth century. These consequences persist despite the myriad of medical advances that have resulted in the lowest perinatal mortality on record.The effects of opiate exposure on the developing fetus have been extensively described in the literature on animal research, in which neurodevelopmental and behavioral abnormalities have been linked to brain region‐specific cellular and molecular findings. The human clinical literature clearly defines the symptoms, timing, and frequency of opiate withdrawal in infants exposed prenatally and documents treatment of withdrawal, which is dependent on the severity of symptoms. A panoply of similarities exist.The adverse complications of maternal opiate addiction during the human prenatal and postnatal period are most significant for the fetus and infant, resulting in increased morbidity and mortality. Other consequences include stillbirth, premature birth, low birth weight, small head circumference at birth and during childhood, poor postnatal somatic growth, transient hypertonia, maladaptive responses to physiologic stresses of hypoxia and hypercarbia, and an increased rate of sudden infant death syndrome, as well as a variety of neurodevelopmental and cognitive delays. Although the factors relating to socioeconomic status, nutrition, and multisubstance abuse add to the challenges of acquiring reliable data, a vast amount of animal and human data suggest that opioids play a critical role in developmental processes that affect the vulnerability and plasticity of the immature brain. In addition, affected infants and children are subject to significant emotional, social, and environmental instability throughout their lives. This must certainly contribute to their neurobehavioral dysfunction. Regardless of these findings, opiates do not appear to have a specific teratogenic effect. © 1995 Wiley‐Liss, Inc.