bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sodium‐dependent steady state L‐alanine accumulation by the body wall of Glycera dibranchiata
Authors: Stevens Bruce R. , Preston Robert L. 
Published: June 2005

AbstractThe time course of alanine accumulation in vitro by body wall of the marine polychaete, Glycera dibranchiata, was studied in the presence and absence of sodium and metabolic inhibitors. Utilizing acute exposure‐retention techniques, the body wall was found to accumulate alanine against a 343:1 (tissue/sea water) concentration gradient at steady state when exposed to an amino acid concentration approximately that of its natural habitat (8.6 × 10−5 M). In the absence of sodium, or in the presence of the metabolic inhibitors 2,4‐dinitrophenol, sodium azide, and ouabain, the steady state alanine gradient is equal to unity. Accumulated alanine probaby resides intracellularly in the body wall, since the apparent extracellular space in body wall accounts for only 6% of the total tissue water. The 343:1 alanine gradient generated by the body wall is thermodynamically plausible in light of the proposed model of alanine influx in body wall epithelial membrane (Stevens and Preston, '80b). The energy available for such influx and accumulation can be derived directly from the sodium chemical gradient plus the membrane electrical potential or potassium gradient.
Arginine vasotocin‐induced in vitro oviductal contractions in Anolis carolinensis: Effect of steroid hormone pretreatment in vivo
Authors: Guillette Louis J. , Jones Richard E. 
Published: June 2005

AbstractOvariectomized female Anolis carolinensis were treated for 14 days with one of the following regimens: (1) estradiol (1 μg/0.05 ml saline/day), (2) progesterone (10 μg/0.05 ml saline/day), or saline (0.05 ml/day). Oviducts then were removed surgically and placed in a bath containing Munsick's solution, to which was added either arginine vasotocin (30 ng/ml) or saline. Although saline produced no effects, AVT‐treated oviducts exhibited rhythmic contractions regardless of pretreatment regimen. Five parameters of the contractions measured were: (1) duration, (2) amplitude, (3) Strength (duration × amplitude), (4) frequency, and (5) rest. Each parameter then was analyzed using a 2 × 3 × 8 mixed, repeated measure design and analysis. Pretreatment with estradiol and progesterone significantly affected contraction strength, amplitude, and duration. Progesterone pretreatment produced oviductal contractions significantly stronger than saline pretreatment (p < 0. 001), whereas estradiol pretreatment produced significantly weaker contractions that saline pretreatment (p < 0.001). These findings are in contrast to those previously recorded for mammals and other reptiles in which estrogens support and progesterone inhibits uterine contractions. These data may suggest a unique adaptation of hormonal control of oviductal contraction in A. carolinensis to the alteration of oviposition during this lizard's reproductive cycle.
Sperm head decondensation by a high molecular weight fraction of sea urchin egg homogenate
Authors: Eng Ludeman A. , Metz Charles B. 
Published: June 2005

AbstractSperm nucleus decondensing activity (NDA) of eggs has been investigated using the gametes of the sea urchin, Lytechinus variegatus. To assay for NDA, isolated sperm heads were exposed to homogenate from mature unfertilized ova and then examined with phase‐contrast optics. NDA is retained by dialysis and requires Ca++ at the time of homogenization as well as at the time of assay. Other divalent cations (Mg++, Sr++, Ba++, Mn++) can substitute for Ca++ but are much less effective. NDA is stable to cold (−20°C, −76°C) but not to heat (56°C). The pH activity optimum is in the range 7–9. NDA is present in the supernatant after centrifugation at 150,000 g for 105 minutes. It elutes shortly following the void volume on a Sephacryl S‐200 column, with an approximate M.W. of 100,000 daltons.
Pattern regulation of mesoderm in transplanted and supernumerary limbs of the cockroach. II. Time course of muscle dedifferentiation
Authors: Steinbach Paul A. 
Published: June 2005

AbstractThe extent and time course of muscle dedifferentiation was followed histologically in transplanted mesothoracic limbs of the cockroach Periplaneta americana. The limbs were grafted to contralateral leg sockets and were oriented such that the anterior‐posterior axis of the graft was reversed relative to that of the socket. The muscles in such a graft dedifferentiate before the first postoperative molt. Muscle dedifferentiation is characterized by the loss of muscle fibers and the appearance of mononuclear cells in the graft. Dedifferentiation begins proximally near the host/graft junction and progressively spreads to distal levels until the only remnants of the original muscle organization are aggregates of mononuclear cells around distal apodemes. Muscles in the thorax which were damaged. During transplantation also de differentiate before the first postoperative molt. Redifferentiation of identifiable muscle can begin as early as the second intermolt period. The dedifferentiation of transplanted mesoderm in not due to the axis reversal, since the muscles in a graft without axis reversal dedifferentiate to the same extent as in grafts with reversed transverse axes. The results are interpreted as indicating that developmental information from nonmuscular tissues in the limb is required for reformation of identifiable muscles.
Methylamine osmoregulatory solutes of elasmobranch fishes counteract urea inhibition of enzymes
Authors: Yancey Paul H. , Somero George N. 
Published: June 2005

AbstractThe intracellular fluids of marine elasmobranchs contain a set of methylamine compounds (trimethylamine oxide, betaine, and sarcosine) which are able to counteract the perturbing effects of urea on enzyme function (apparent Michaelis constant (Km) and maximal velocity). The counteracting effects of the methylamine compounds and urea are maximal at a 2:1 ratio [urea]:[methylamines]. This is the same concentration ratio for these osmolytes found in the cells of marine elasmobranchs, holocephalans, and the coelacanth.The counteracting effects of the methylamine solutes and urea are observed with enzymes from non‐elasmobranchs as well as elasmobranchs, indicating that the enzymes of elasmobranchs are not specially adapted to function in the presence of urea or the methylamine osmolytes. Rather, the effects of urea and the methylamines on enzymes probably reflect fundamental protein‐solute interactions.The urea tolerance conferred by the methylamine solutes may have played an important role in elasmobranch evolution. The relief from urea perturbation afforded by these methylamines may have precluded the requirement for widespread modifications in the sequences of elasmobranch proteins to allow these proteins to function in the presence of perturbing urea concentrations.
Pineal involvement in the control of behavioral thermoregulation of the white sucker, Catostomus commersoni
Authors: Kavaliers Martin , Ralph Charles L. 
Published: June 2005

AbstractWhite suckers select a higher body temperature at night and a lower temperature during daytime. Removal of the pineal organ eliminated their diel rhythm of behavioral thermoregulation. After pinealectomy fish failed to select a lower daytime temperature. These results suggest that the pineal organ is involved in the control of behavioral thermoregulation of this teleost fish.
Pituitary stimulation of parathyroid hormone secretion: Evidence in cattle for a parathyroid stimulating hormone
Authors: Latman Neal S. 
Published: June 2005

AbstractA number of previous investigations have indicated that the pituitary may directly stimulate of secretion of parathyroid hormone. Others have disagreed. With the recent development of an in vitro bovine parathyroid perfusion system, the direct effect of suspected secretagogues can be assessed on a dynamic, ongoing basis.A partially purified pituitary extract (preparation A) was injected into calves. The plasma calcium increased an average of 1.1 mg/100 ml plasma. No increase of immunoreactive parathyroid hormone (iPTH) was detected, however, in the peripheral plasma prior to the increase in plasma calcium concentration. Since the peripheral plasma iPTH concentration has been shown to be relatively insensitive to changes in the secretion rate, the inability to detect a change in the iPTH concentration does not preclude a direct stimulating effect of the pituitary on the parathyroid.When preparation A was tested on in vitro perfused bovine parathyroid glands, a 30% average increase in secretion of c‐iPTH (carboxy terminus) and a 56% average increase in secretion of n‐iPTH (amino terminus) was observed under normocalcemic conditions. Under conditions of hypercalcemia, there was an average increase in the c‐iPTH secretion rate of 60% and an average n‐iPTH secretion rate increase of 88%. A failure of TSH, LH, GH, ADH, oxytocin, and prolactin to stimulate iPTH was observed. Previous reports have eliminated ACTH, MSH, and lipotropin as possible parathyroid secretagogues.The concept of a parathyroid stimulating hormone (PTSH) located in the pituitary that can directly stimulate the parathyroid gland to secrete parathyroid hormone is consistent with the results of this investigation.
The direction of evolution in the Drosophila melanogaster species subgroup based on functional analysis of the crystal cells
Authors: Rizki T. M. , Rizki Rose M. 
Published: June 2005

AbstractThe crystal cells in the hemolymph of Drosophila melanogaster contain paracrystalline inclusions and phenol oxidase. Melanization of this type of blood cell can be induced by treatment of larvae with hot water. By using this functional criterion to establish cell homology we compared the shape of the inclusions in the crystal cells of the D. melanogaster species subgroup and a number of distantly related species of Drosophila. The crystal cell inclusions in four of the sibling species (simulans, erecta, mauritiana, yakuba) are the same as those found in D. melanogaster. In the fifth species, D. teissieri, the crystal cell inclusions resemble those found in the hemocytes of the other larval drosophilids that were examined rather than those of D. melanogaster. On the basis of these observations and the phylogenetic relationships deduced from analysis of chromosomal inversions by Lemeunier and Ashburner ('76), we propose that D. teissieri is closer to the ancestral form or is the ancestral species of the melanogaster species subgroup of Drosophila. This is the first instance in which a hemocyte type has been used to determine the direction of evolution within a subgroup of insect species.
Glycerol permeabilities of fertilized and unfertilized mouse ova
Authors: Jackowski Suzanne , Leibo S. P. , Mazur Peter 
Published: June 2005

AbstractThe coefficients of permeability to glycerol, Pglyc, and their temperature‐dependence were determined from volume changes of fertilized and unfertilized mouse ova under hyperosmotic conditions. Fertilization caused a significant increase in the value of Pglyc. Unfertilized ova exhibited Pglyc values of 1 × 10−5, 2 × 10−6, and 5 × 10−7 cm/min at ∼20°C, ∼12°C, and ∼3°C, respectively. Fertilized ova exhibited Pglyc values of 3.4 × 10−5, 1.3 × 10−5, and 4.7 × 10−6 cm/min at ∼20°C, ∼12°C, and ∼3°C, respectively. The activation energy of glycerol permeation into fertilized and unfertilized ova was calculated to be 18.7 and 28.4 kcal/mol, respectively. Fertilization caused a rather dramatic increase in glycerol permeability, the major extent of which occurred within about 3 hours after fertilization. Pglyc was also measured at ∼20°C by isotope uptake. Glycerol uptake calculated indirectly from the volume changes of the ova agreed well with that measured directly by labeled glycerol uptake. It was also found that the zona pellucida of fertilized and unfertilized ova did not detectably impede the permeation by glycerol.
Further characterization of female sterile (1) 1304 mutant of Drosophila melanogaster
Authors: Mulligan Pamela Khipple , Rasch Ellen M. 
Published: June 2005

AbstractThe Drosophila melanogastor mutant fs(1) 1304 (1‐19 ± 2) has been characterized using various experimental approaches. The mutant ap4 (2‐55.2), used as a control in some of the experiments reported in this paper, has also been examined more carefully. Electrophoresis of ovarian extracts from the mutants on polyacrylamide gels yield results suggesting that vitellogenesis is completely inhibited in ap4/ap4 females, while it proceeds at an abnormally slow rate in fs/fs females. Both mutants accumulate hemolymph proteins in amounts in excess of those found in the hemolymph of wild type females, suggesting that uptake of proteins from the hemolymph is affected by both the mutant genes. Qualitative differences in the banding patterns obtained from the hemolymph of wild type and ap4 female suggest that homozygous ap4 females may also be defective in the synthesis or processing of yolk proteins. Three of the protein bands observed in our electropherograms are suspected to represent yolk proteins, and an additional band is thought to represent an aggregate of the three yolk proteins.Neither juvenile hormone nor ecdysone treatment enhance vitellogenesis in fs(1)1304, although ap4 females produce yolky oocytes after JH treatment, in agreement with previously reported results. Ovarian transplantation studies suggest that fs(1)1304 behaves autonomously. Previous studies have shown that ap4 females behave non‐autonomously.
Cuticular lipid biosynthesis in the scorpion, Paruroctonus mesaensis
Authors: Hadley Neil F. , Hall Richard L. 
Published: June 2005

AbstractThe synthesis of cuticular and hemolymph lipids in the scorpion Paruroctonus mesaensis, was examined using radiolabeled acetate and palmitic acid. Incorporation of 1‐14C‐acetate into cuticular lipids was very low (0.03–0.13% of injected label), with the hydrocarbons exhibiting only trace (CPM's not significantly higher than background) radioactivity after 24 hours. Cuticular alcohols had the highest incorporation (ca. 80%) followed by free fatty acids and triglycerides. Hemolymph lipids also showed poor incorporation of labeled acetate (0.01%) and little activity in the hydrocarbon fraction. Incorporation of 1‐14C‐palmitic acid into cuticular lipids (0.86–1.21%) and hemolymph lipids (0.62–1.00%) was slightly higher, but still well below incorporation values observed for insects. The majority of the label appeared in the free fatty acids; hydrocarbons continued to show only trace radioactivity. Except for differences in the relative amounts of specific components, cuticular and hemolymph hydrocarbons were similar in composition. These results suggest that hydrocarbon biosynthesis in adult scorpions is very low during the intermoult period or that other compounds are preferred precursors.
Periodic spawning of three types of the ascidian, Halocynthia roretzi (Drasche), under continuous light conditions
Authors: Numakunai Takaharu , Hoshino Zen‐Ichiro 
Published: June 2005

AbstractWe observed the spawning behavior of three types of H. roretzi kept under continuous light conditions for a 2 week period. Three different spawning behaviors were observed. Type A spawned both under continuous light and continuous darkness. Type B spawned under continuous light and Type C under continuous dakness. All these type spawned twice a day. In contrast, animals under the natural light cycle spawn once a day. We propose that there are at least two periodic factors that define their spawning times. Spawning seasons were prolonged or advanced several months by keeping animals in cold sea water or in warm sea water. Their spawning times remained basically unchanged, although to some extent (depending upon the sea water temperature) they changed.
Effects of divalent cations on amino acid and divalent cation fluxes in gills of the bivalve mollusc, Mytilus californianus
Authors: Swinehart James H. , Crowe John H. , Giannini Albert P. , Rosenbaum David A. 
Published: June 2005

AbstractEffects of the deletion of Ca++, Mg++, or Ca++ and Mg++ on the leakage of primary amines, Ca++, and Mg++ from gills of Mytilus californianus were studied. In the absence of Ca++ the gills leak primary amines and Ca++ for about 30 minutes, after which the primary amines are reabsorbed. In the absence of Mg++ the gills leak primary amines, with no net reabsorption for at least 90 minutes, and show rapid leakage of Mg++. In the absence of both Ca++ and Mg++ amino acid leakage is initially less than in the absence of only one of the cations. Measurements of the kinetics of leakages of Ca++ and Mg++ are consistent with the hypothesis that both ions are associated with the cell surface, but the affinity of Ca++ for the cell surface is greater than that of Mg++.In the absence of Mg++, the influx of 14C‐glycine was depressed to about 1/3 that seen in controls, while deletion of Ca++ had no effect on the rate of influx. Increasing the [Mg++] stepwise between 5 × 10−6 and 1 × 10−1 M results in a sigmoidal increase in the rate of influx of 14C‐glycine and a hyperbolic increase in the y‐intercept of influx curves.
Responses of the screening pigments in the compound eye of Neomysis integer (Crustacea: Mysidacea)
Authors: Hallberg E. , Andersson M. , Nilsson D.‐E. 
Published: June 2005

AbstractThe following responses of the screening pigment in the compound eyes of the mysid Neomysis integer(Leach) were studied using histological methods: viz. the light and dark adaptation, the reaction of the light‐adapted eyes towards different light intensities, and the pigment distribution during prolonged exposure to light and darkness. The light and dark adaptations of the screening pigments are characterized by a strong initial reaction, which is followed by a gradual approach to a more or less stable state. In the light adaptation of the proximal pigment, the initial distal movement is especially pronounced, followed by a phase during which the pigment moves proximally. The eye is light‐adapted in about 20 minutes. Dark adaptation, on the other hand, is a slower process requiring more than an hour. The position of the pigment in the light‐adapted eyes is influenced by the light intensity, as the limits of the pigment shield progress in increasing light intensities. In animals subjected to total darkness or continuous illumination, the variations of the pigment screen could not be correlated with cyclic diurnal migrations.
Characterization of the methylxanthine‐induced propagated wave phenomenon in striated muscle
Authors: Coleman Annette W. , Coleman John R. 
Published: June 2005

AbstractEscalation is a propagated wave phenomenon readily observable in chick skeletal muscle fibers growing in culture. It occurs in fibers bathed in methylxanthines, halothane, or quinine, at concentrations associated with twitch potentiation. From the results of a variety of experiments, an explanation of the phenomenon is proposed. Cation requirements suggest that a wave may be initiated in conjunction with a spontaneous calcium influx or calcium spike; and drug concentration, temperature, and extracellular potassium effects support the theory that wave propagation occurs by calcium‐induced calcium release from the sarcoplasmic reticulum. The optical effect may then reflect osmotic changes associated with the transient calcium release. Escalation is not restricted to cultured muscle, nor to chick. At appropriate temperatures and in the presence of methylxanthines, escalation has been observed in chick, frog, and rat skeletal muscle. This suggests that it is a subthreshold event, related to contraction, capable of providing further insight into excitation‐contraction coupling. The superior visibility conditions accessibility to experimental manipulation make cultured chick skeletal muscle fibers suitable subjects for such study.
Dominant lethal induction by ethyl methanesulfonate in the male axolotl (Ambystoma mexicanum)
Authors: Armstrong John B. , Gillespie Laura L. 
Published: June 2005

AbstractWhen male axolotls (Ambystoma mexicanum) were treated with ethyl methanesulfonate (EMS) and mated at regular intervals thereafter, the incidence of embryonic abnormalities among the F1 progeny increased until a time was reached when none survived to hatching. At 100 mg/1 EMS, this point was reached about 130 days after treatment. Thereafter, the frequency of abnormalities gradually decreased to control levels. At higher concentrations, abnormalities were seen in spawnings obtained sooner after treatment, and also at earlier developmental stages. The pattern is similar to that reported for the mouse, which has been attributed to differential sensitivity of the various germ cell stages to the mutagenic agent. The time course, however, is greatly extended in the axolotl. In future experiments we will be looking for gene mutations, primarily before and after the period of peak mortality.
Nuclear basic protein changes during spermiogenesis in the longnose skate and the spiny dogfish
Authors: Bols N. C. , Boliska S. A. , Rainville J. B. , Kasinsky H. E. 
Published: June 2005

AbstractNuclear shape and the organization of nuclei within the seminiferous follicles have been used to divide spermiogenesis in the longnose skate, Raja rhina, into eight stages and in the spiny dogfish, Squalus acanthias, into seven stages. Cytochemical techniques for basic proteins reveal that as spermatid nuclei begin to elongate they have the somatic histone complement, and as they complete elongation they contain a very arginine‐rich, TCA‐extractable complement, or the salmon sperm histone type. After the nuclei have developed their ultimate corkscrew shape the final transition takes place to a very arginine‐rich, TCA‐stable complement, or the mammalian sperm histone type. These nuclei were not rich in sulfhydryl groups, but they were extractable with sodium thioglycolate. In addition, a number of variables affecting TCA extraction and subsequent alkaline fast green staining are described.
Lens formation from cornea in the presence of the old lens in larval Xenopus laevis
Authors: Bosco Luigi , Filoni Sergio , Cioni Carla 
Published: June 2005

AbstractThree different types of experiments were carried out to investigate the role of the lens in lens‐forming transformations of the outer cornea of Xenopus laevis tadpoles (at stage 51, as defined by Nieuwkoop and Faber, '56): 1) simple lentectomy; 2) incision of outer and inner cornea in the region opposite the dorsal iris without lens removal; and 3) incision of outer and inner cornea and perforation of dorsal iris without lens removal. The results indicate that the outer cornea of Xenopus laevis larvae has lens‐forming competence, even in the presence of the old lens, only when direct communication has been set up between the outer cornea and the environment of the vitreous chamber. These data indicate that the inhibition exerted by the lens on lens‐forming transformations of the outer cornea is mechanical in nature.