bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of changes in Ca2+ concentration of the culture medium on the in vitro development of 11‐day mouse embryos
Authors: Nakashima K. , Fujiki Y. 
Published: June 2005

AbstractThe present study was designed to examine the effects of changes in Ca2+ concentration in a culture medium on the development of 11‐day mouse embryos (plug day = day 0). The embryos were individually cultured for 24 hours by rotating bottles using a culture medium of 25% rat serum and 75% Waymouth's medium. The Ca2+ concentration was changed by adding EGTA or CaCl2 to the Waymouth's medium. The Ca2+ concentrations examined were 0.5, 1.0, 1.5, 2.0, and 3.0 mM in 95% oxygen and 1.0, 2.0, and 3.0 mM in 60% oxygen. Development of embryos was evaluated on the basis of heartbeat, survival, growth, and differentiation. In 95% oxygen, the best survival was obtained at 1.5 mM Ca2+, while growth and differentiation were little affected by changes in Ca2+ concentrations except at 0.5 mM. In 60% oxygen, rhythmical heartbeats were difficult to maintain in many of the embryos at all Ca2+ concentrations examined, although reasonable development was obtained at 3.0 mM Ca2+. The optimal conditions were a culture medium containing 1.5 mM Ca2+ and an oxygen concentration of 95%. The addition of Waymouth's medium to the rat serum is useful in controlling the Ca2+ concentration of the culture medium.
Age‐dependent changes in fluorescent neurons in the brain of Notoplana acticola, a polyclad flatworm
Authors: Hauser Melinda , Koopowitz Harold 
Published: June 2005

AbstractThe formaldehyde‐glutaraldehyde‐sucrose (FGS) method for in situ localization of catecholamines has been applied to the nervous system of the marine polyclad flatworm Notoplana acticola. This histochemical fluorescence technique revealed the presence of a small population of fluorescent cells within the brain. The number and positions of these neurons were constant in animals of the same size, but varied with the size of the worm. The brains of small animals (8 mm in length) were found to contain 20 fluorescent cells, whereas the largest animals studied (30 mm in length) were found to have 28 such cells. Various intermediate cell numbers were found in animals between these two sizes. The origin of the newly added fluorescent cells is uncertain. Peripheral fluorescence was found in association with the tentacular ocelli (eyespots) and interneurons within the ventral submuscular nerve plexus. The fluorescent spectrum from these cells measured in situ had a λmax of 526 nm. Treatment with HCl shifts this peak to 530 nm. L‐dopamine fluoresces with a similar peak emission before HCl treatment (525.5 nm) and shifts to the appropriate longer wavelength (530 nm) following acidification. This strongly suggests that the fluorescent substance in the neurons is dopaminergic in nature.
Heat shock protein induction and induced thermal tolerance are independent in adult salamanders
Authors: Easton Douglas P. , Rutledge Paul S. , Spotila James R. 
Published: June 2005

AbstractEctothermic vertebrates become thermally tolerant (heat hardened) after exposure to heat shock. Eukaryotic cells show a similar response. Cellular thermal tolerance is correlated with the induction of heat shock proteins (hsps). We have investigated the relationship between heat hardening in salamanders and the induction of hsps in the tissues of these organisms. Although the synthesis of hsps can be induced in these animals by sublethal heat shocks, conditions required for hsp induction and heat hardening often do not coincide. We conclude that induced thermal tolerance in adult salamanders is independent of hsp induction in their tissues.
Some effects of adrenaline on anion transport and nitrite‐induced methaemoglobin formation in the rainbow trout (Salmo gairdneri Richardson)
Authors: Williams E. M. , Eddy F. B. 
Published: June 2005

AbstractThe effects of adrenaline on branchial anion transport and nitrite‐induced methaemoglobinaemia have been investigated in rainbow trout. Nitrite uptake and efflux results suggest that adrenaline effects a net anion efflux principally by stimulation of the unidirectional branchial anion efflux. In oxygenated whole blood nitrite‐induced methaemoglobin was significantly reduced in the presence of adrenaline. The physiological and environmental consequences of nitrite‐induced stress are discussed.
Craniofacial development mutant pi (pinhead) in the Axolotl (Ambystoma mexicanum) which exhibits reduced interocular distance
Authors: Neff Anton W. , Briggs F. , Chung H.‐M. 
Published: June 2005

AbstractThe genetics, gross morphology, histology, and experimental production of a phenocopy of a new mutant gene in the Mexican axolotl (Ambystoma mexicanum) are described. The mutant phenotype, termed pin‐head (pi), is characterized at the hatching stage by craniofacial abnormalities including reduced interocular distance (including cases of cyclopia). Rostral head structures such as the olfactory organs, eyes, forebrain, and oral cavity are primarily affected. More posterior structures beginning with the pharynx, otic vesicles, hindbrain, notochord, and gills appear normal. The mutant gene shows variable penetrance and appears to be a simple recessive with increased penetrance when fertile eggs are reared to the hatching state at 10°C (cold sensitivity). Evidence that this gene may affect prechordal mesoderm and plate development is presented. Phenocopies of the pi mutant were produced by the surgical removal of the prechordal mesoderm and plate from neural plate stage embryos.
Androgenic regulation of epididymal function in the skink, Mabuya carinata (Schn.)
Authors: Shivanandappa T. , Sarkar H. B. Devaraj 
Published: June 2005

AbstractAndrogenic control of epididymal function in reptiles has been studied in the skink, Mabuya carinata, by castration and androgen administration on histological, histochemical, and biochemical parameters. Castration of male skinks during the reproductive phase (Nov.–Dec.) leads to atrophy and regression of the epididymal epithelium with histochemically demonstrable loss of acid and alkaline phosphatase activities in the epithelium. Biochemically, reduction in DNA and protein contents and marked decrease in the activities of acid and alkaline phosphatases were observed. Administration of testosterone propionate (250 μg per animal on alternate days for 24 days) leads to hypertrophy of the epididymis, increased cell height, and histochemically demonstrable induction of acid and alkaline phosphatases in the epithelium. DNA and protein levels were also restored. In the quiescent phase (April–June) when the epididymis is fully regressed, the histological, histochemical and biochemical profile is comparable to that of castrated lizards in the reproductive phase. Administration of testosterone propionate to intact lizards leads to hypertrophy and stimulation of all the parameters, reminiscent of the condition in the reproductive phase. Alkaline phosphatase was found to be highly sensitive to androgenic deprivation and stimulation.
Thyroxine content of eggs and larvae of coho salmon, Oncorhynchus kisutch
Authors: Kobuke Louise , Specker Jennifer L. , Bern Howard A. 
Published: June 2005

AbstractThe whole‐animal content of the thyroid hormone thyroxine (T4) was measured in embryonic and larval coho salmon (Oncorhynchus kisutch) by radioimmunoassay following the validation of an extraction method. The embryonic yolk, at 20 days after fertilization and 10 days before hatching, was found to have 5.3 ± 0.3 ng T4 (mean ± SEM). At hatching, the total T4 content decreased to 4.4 ± 0.3 ng, of which 96% remained in the yolk and 4% was distributed in the larva. T4 content decreased to 1.5 ± 0.1 ng during the 30 days of larval development. The first increases in T4 were detected within 2 weeks following emergence from the substrate of the actively feeding juvenile; the newly emerged salmon responds significantly to bovine TSH. The presence and clearance of T4 from the yolk suggest that T4 may be critical to normal larval morphogenesis, that initially the T4 is of maternal origin, and that the hypothalamo‐adenohypophysial‐thyroid axis begins to function independently at or near the time of emergence.
Lactate dehydrogenase homopolymer of hagfish heart and the single lactate dehydrogenase of lampreys display greater immunochemical similarity to LDHC4 than to LDHB4 of teleost fish
Authors: Baldwin J. , Lake P. S. 
Published: June 2005

AbstractAntisera produced against the single LDH enzymes from representatives of all three lamprey families and against the LDHA4 and LDHB4 enzymes of hagfish were tested for their ability to cross react with LDHC4 and LDHB4 purified from liver and heart of the Southern bastard red cod (Pseudophycis barbata, Order Gadiformes). The lamprey and hagfish heart LDH enzymes displayed greater immunochemical similarity to cod LDHC4, a result consistent with the view that the C subunit predates the B subunit.
Invertebrate red blood cell carbonic anhydrase
Authors: Henry Raymond P. 
Published: June 2005

AbstractThis is the first report documenting the presence of carbonic anhydrase (CA) for any invertebrate red cells. CA activity was measured in plasma, hemolysates of blood cells, and in hemolymph of selected species of invertebrates. Annelid red blood cells (RBC) and sipunculid pink blood cells both possessed significant levels of CA activity. Molluscan RBC, on the other hand, lacked CA activity. The distribution appears to have fallen along phylogenetic lines, with CA being present only in blood cells of the two more closely related groups. However, the presence of extracellular CA was confirmed in oyster hemolymph. Oyster hemolymph CA showed a similar affinity (Ki) for the sulfonamide inhibitors acetazolamide and ethoxzolamide, as did the vertebrate RBC CA II isozyme, supporting the idea that this isozyme could be the ancestral form of the enzyme.
Maternal calcium contribution to glochidial shells in freshwater mussels (Eulamellibranchia: Unionidae)
Authors: Silverman Harold , Todd Kays W. , Dietz Thomas H. 
Published: June 2005

AbstractPrevious work has demonstrated that calcium concretions, located in the gills of freshwater mussels, disappear during the reproductive season. While calcium is being mobilized, there is no increase in calcium content in the blood. The current study documents the passage of maternal calcium to glochidia, for the production of calcium carbonate shells while the larvae are brooding in the water channels of the lateral gills; 45Ca was injected into Anodonta grandis 2 mo before the onset of reproduction and the label was distributed through the animal but was concentrated largely in the calcium concretions. Following glochidia development, 45Ca was found incorporated in the shell of the embryos. To determine the extent of the maternal passage of calcium to the embryos, Ligumia subrostrata containing embryos undergoing shell formation were exposed to 45Ca, either by injection into the blood or by inclusion of label in the bathing medium. The amount of label found in the developing glochidia is proportional to the 45Ca content in the blood of the maternal animal. Isolated glochidia directly exposed to label will adsorb 45Ca onto their shells, but there is little addition of label to glochidia in intact maternal gills during the bath exposure experiments. The results indicate that the maternal contribution of 45Ca is over 90%, with direct contribution from the bathing medium accounting for less than 8%. These results indicate that the branchial water channel in which the embryos are developing is isolated from bath 45Ca. This study presents morphological evidence that the physiological isolation of glochidial shells from bath 45Ca is due to a rearrangement of water channel morphology, and that the chamber, in which the embryos develop, has no contact with the bathing medium.
Specificity of sperm‐binding Wolffian duct proteins in the rooster and their persistence on spermatozoa in the female host glands
Authors: Morris S. A. , Howarth B. , Crim J. W. , de Cordoba S. Rodriguez , Esponda P. , Bedford J. M. 
Published: June 2005

AbstractUnlike those of mammals, chicken spermatozoa can develop their fertilizing ability before they leave the testis to pass into the Wollfian duct; moreover, chicken spermatozoa do not require a period of capacitation in the female tract. A question arises, therefore, as to the significance of secretory proteins shown to bind to the surface of chicken spermatozoa as they pass into and through the Wolffian duct. Using anti‐Wolffian duct fluid IgG as a probe visualized by immunoperoxidase staining, the present investigation confirms that testicular spermatozoa of quail and turkey as well as chicken do not have any surface determinants in common with those present in Wolffian duct secretions. By contrast, those in the lower portion of the vas deferens display a strong reaction with anti‐Wolffian fluid IgG over their entire surface, and immunoprecipitation studies suggest that this reflects the binding of four Wolffian duct proteins. Since a reaction to the antichicken fluid IgG is shown also by mature quail and turkey, but not duck and pigeon spermatozoa, the Wolffian components that coat spermatozoa in birds appear to have a specificity confined to the same order, in this case the Galliformes. Following vaginal or intramagnal insemination, spermatozoa present 48 hours later in the uterovaginal host glands and infundibulum glands, respectively, still reacted strongly. This finding that Wolffian duct components persist on the surface of spermatozoa in the female tract is consistent with the possibility that they have some role in sperm storage or survival in female birds.
Chromatin decondensation and DNA synthesis in human sperm activated in vitro by using Xenopus laevis egg extracts
Authors: Brown David B. , Blake Emily J. , Wolgemuth Debra J. , Gordon Katherine , Ruddle Frank H. 
Published: June 2005

AbstractAn in vitro sperm activation system was used to study nuclear swelling‐chromatin decondensation and DNA synthesis; processes that occur in vivo following fertilization. Lysolecithin‐permeabilized human sperm were incubated in Xenopus laevis egg extract and examined by using phase‐contrast light microscopy, electron microscopy, and autoradiography. During a 3‐hour incubation, the activated sperm nuclear chromatin underwent a decondensation‐recondensation cycle during which DNA was synthesized. This also occurred when egg extract was given a 3‐hour preincubation before the addition of the sperm, suggesting that the factor(s) required for initiating the decondensation‐recondensation cycle is associated with the sperm. Because both nuclear swelling and DNA synthesis were found to be reproducible and quantifiable, we studied the effect of various agents on the two processes, characterizing the critical component(s) in the egg extract that induces these events. EGTA was found to have no effect on the induced nuclear swelling or DNA synthesis that occurs in the activated sperm. Freezing and thawing the extract or treating the extract with aphidicolin also had no effect on subsequent nuclear swelling; however, the DNA synthesis activity was blocked. Sperm incubated in extract treated with alkaline phosphatase (AP) had both nuclear swelling and DNA synthesis blocked. However, if the sperm were pretreated with DTT, and then incubated with the AP‐treated extract, only the DNA synthesis activity of the extract was blocked. When the extract was treated with serine protease inhibitors (PMSF, soybean trypsin inhibitor, or α‐2‐macroglobulin), nuclear swelling occurred; however, DNA synthesis was blocked. These data suggest that phosphoproteins are involved in one or more of the activation events and that a serine protease(s) is involved in the synthesis of DNA.
Seasonal changes in the effects of arginine vasotocin and stretch on Anolis uterine contractions in vitro
Authors: Jones Richard E. , Lopez Kristin H. , Summers Cliff H. , Austin Harriet B. 
Published: June 2005

AbstractWe determined the effects of acute stretch on spontaneous and arginine vasotocin (AVT)‐driven contractions of the Anolis carolinensis uterus in vitro. Whole uteri from reproductively inactive females (October) were placed in a bath of oxygenated 32°C Anolis “Ringer's.” Two initial tensions were utilized, 1.5 g or 15 g, the latter being an estimate of the tension on the wall of a uterine compartment. Uteri were then exposed to either saline or AVT (50 ng/ml), and spontaneous or AVT‐driven contractions were recorded for 20 min with the use of a strain gauge and physiograph. A similar experiment was performed on uteri from reproductively active females in the summer (June).Our results indicate that the effects of acute stretch and AVT on uterine contractility were qualitatively similar in summer and fall. That is, 1) AVT induced a tonic contraction; 2) stretch decreased the duration of the tonic contraction; 3) the saline‐treated uteri exhibited spontaneous rhythmic contractions; 4) AVT increased the amplitude of the rhythmic contractions, but only at the lower tension; 5) there were no effects of AVT on the timing (contraction interval, duration, rest interval) of the rhythmic contractions; and 6) stretch increased the frequency of the rhythmic contractions. Season greatly influenced the magnitude of these contractile phenomena. Uteri tested during the breeding season exhibited greater distensibility, an increase in the amplitude and duration of the AVT‐driven tonic contraction, and an increase in the frequency of both spontaneous and AVT‐driven rhythmic contractions because of a decrease in both contraction duration and rest interval. Possible causes of these seasonal changes, as well as the relevancy of the stretch effects to the biology of the uterine egg compartment, are discussed.
Organ blood flow and brown adipose tissue oxygen consumption during noradrenaline‐induced nonshivering thermogenesis in the djungarian hamster
Authors: Puchalski Wolfgang , Böckler Heinz , Heldmaier Gerhard , Langefeld Martin 
Published: June 2005

AbstractDuring NA‐induced NST blood flow through BAT increased from 0.18 ml min−1 to 3.21 ml min−1 in 23 °C acclimated (equals thermoneutrality) and from 0.61 ml min−1 to 9.67 ml min−1 in outdoors (−2 to 12°C Ta) acclimated Djungarian hamsters. In 23 °C acclimated hamsters this increase was accomplished by a diversion of blood flow from visceral organs without a change in cardiac output (19.7 versus 20.5 ml min−1 before and after NA). In outdoors acclimated hamsters we also observed a redistribution of blood flow from the viscera to BAT. In addition, cardiac output increased from 24.3 to 38.8 ml min−1. Metabolic rate of BAT in situ was determined from organ blood flow and the (A‐V)O2 of blood across the interscapular BAT. BAT of outdoor acclimated hamsters showed a significantly higher metabolism in comparison to 23 °C acclimated hamsters (81.1 versus 30.4 mlO2h−1). Furthermore, this calculation revealed that 28% (23 °C acclimated hamsters) and 61% (outdoors acclimated hamsters) of total NST were located in BAT of Phodopus sungorus.
Protein kinase C as a possible mediator of goldfish (Carassius auratus) ovulation
Authors: Ranjan Mukul , Goetz Frederick W. 
Published: June 2005

AbstractThe possible involvement of protein kinase C in goldfish Carassius auratus) ovulation was investigated. In vitro ovulation of oocytes that had undergone germinal vesicle breakdown and follicular wall detachment in vivo was observed with both a phorbol ester, phorbol‐12‐myristate‐13‐acetate, and a calcium ionophore, A23187. A combination of these two factors exhibited classic synergism and induced ovulation at much lower concentrations. Since protein kinase C is physiologically activated by diacylglycerols, three sn‐1,2‐diacylglycerols were also tested in combination with A23187. Of these, sn‐1‐oleoyl‐2‐acetylglycerol was ineffective, while sn‐1,2‐dioctanoylglycerol (diC8 and sn‐1,2‐dihexanoylglycerol (diC6) were found to synergize with the calcium ionophore even at the lowest levels tested. diC8 was more effective than diC6 at comparable levels. In vitro ovulation stimulated with phorbol ester and ionophore could be blocked with nordihydroguaiaretic acid at 10 μg/ml, while indomethacin at similar or higher (20 μg/ml) levels was ineffective. This suggests the involvement of lipoxygenase products in conjunction with protein kinase C activation during ovulation in this species. While a direct participation of protein kinase C and its mechanism of action remain to be demonstrated, these results indicate its involvement in the control of ovulation in goldfish.
Myoblast differentiation is induced by nerve transplanted to chick embryo legs
Authors: Bonner Philip H. 
Published: June 2005

AbstractChick embryos were denervated early in development in order to disrupt the normal inductive interactions between the nervous system and developing populations of mononucleated myoblasts and their precursors in the leg. Neural tissue, either spinal cord or ciliary ganglion, was transplanted to one leg of the denervated embryos; the other leg remained aneural. Clonal analysis of cell populations in the transplant‐containing legs showed that ectopic nerve tissue can recapitulate some of the neuromuscular interactions that occur in normally developing embryos. Chief among these was the observation that transplantation induced the appearance of the CMR‐III myoblast class in the leg muscle. Since the process by which CMR‐III myoblasts are produced from a precursor is dependent on nerve both in vivo and in vitro (Bonner, P.H. and T.R. Adams, Dev. Biol., 90:175–184, 1982), it was concluded that transplanted nerve tissue can also induce myoblast differentiation.
Female heterogamety in the swordtail, Xiphophorus alvarezi rosen (Pisces, Poeciliidae), with comments on a natural polymorphism affecting sword coloration
Authors: Kallman Klaus D. , Bao Isaac Y. 
Published: June 2005

AbstractThe sex‐determining mechanism of swordtails (Xiphophorus, Poeciliidae, Pisces) is poorly understood, because many laboratory strains of these species are characterized by biased sex ratios in either the male or female direction. Because of these ratios sex determination is said to be controlled by numerous male and female factors scattered over many chromosomes. However, direct experimental evidence for the polygenic theory is absent. Three strains of X. alvarezi were derived from natural populations in Guatemala, two of which (Dolores, Candelaria) always exhibit a ratio of 1:1, whereas the third one (San Ramón) shows a preponderance of males. Males of X. alvarezi, like those of other species of swordtails, develop a caudal appendage or sword at maturity. Chromatophores with carotenoid pigment (orange) are present in the sword of Dolores males and pigment cells containing sepiapterin (green) are present in the swords of males and the other two stocks. F1 and backcross hybrids were produced between the Dolores and Candelaria stocks. The sex ratios of all hybrid pedigrees was always in statistical agreement with unity. The pattern of inheritance of the two pigmentary traits demonstrated sex‐linkage, with female heterogamety (WY ♀ ♀ ‐ YY ♂ ♂).