bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategy of oxidative metabolism in bull spermatozoa
Authors: Storey Bayard T. 
Published: June 2005

AbstractHypotonically treated bull epididymal spermatozoa (HTBES) were prepared by the same technique used for hypotonically treated rabbit epididymal spermatozoa (HTRES) in order to compare the mitochondrial activities of the bull gamete to those of the rabbit gamete. Bull sperm mitochondria oxidize pyruvate plus malate, lactate plus malate, and acetyl‐L‐carnitine plus malate with energy coupling. The rate of O2 uptake by HTBES with pyruvate plus malate is more rapid than lactate plus malate. Bull sperm mitochondria also oxidize glutamate plus malate, L‐3‐glycerolphosphate, and palmitoyl CoA plus carnitine as well as palmitoyl‐L‐carnitine. The first mitochondrial activity enables bull sperm to utilize the malate/aspartate shuttle as well as the lactate/pyruvate shuttle to transfer reducing equivalents from NADH produced by glycolysis in the cytosol to the mitochondria for complete oxidation by O2. The latter two activities enable bovine sperm to utilize endogenous lipids and phospholipids for energy metabolism. Rabbit sperm mitochondria lack these three mitochondrial oxidative activities but have maximal oxidative activity with lactate as substrate (Storey and Kayne ('77). Bull spermatozoa are equipped metabolically for survival in the bovine oviduct lumen, which has a low content of oxidizable substrate, while rabbit spermatozoa are equipped for survival in the rabbit oviduct lumen, which has a high lactate content. The hypothesis was proposed that mitochondrial activities of sperm of a given species are adapted to the substrate content of the oviduct lumen of that species and so have predictive value concerning oviduct lumen content.
Neurobiology of the stoloniferan octocoral Clavularia sp.
Authors: Satterlie Richard A. , Case James F. 
Published: June 2005

AbstractElectrical impulses representing a colonial conducting system were recorded from polyp oral disks of Clavularia sp. with extracellular suction electrodes. The colonial system is through‐conducting and initiates colony‐wide polyp contraction and withdrawal. Activation of polyp musculature is dependent upon stimulus (colonial impulse) number and frequency. A synaptic nerve net is present throughout the ectoderm of the colony and polyps and presumably represents the colonial system from which impulses were recorded.Each polyp can bend, feed, and withdraw independently, and this activity does not spread to neighboring polyps. Application of beef liver extract to polyp tentacles induces oral‐directed flexions of the stimulated tentacles (feeding responses). A burst of electrical impulses, recorded from polyp oral disks, accompanies the feeding responses. Putative tentacular sensory structures, examined by transmission and scanning electron microscopy, consist of ciliary cone‐nematocyte complexes. Each complex has a central nematocyte, bearing an apical cilium, and several surrounding cells, providing microvilli to the cone.
Transcriptional activity in lysates of cultured mesenchymal cells from embryonic tooth germs
Authors: Kestler D. P. , Kollar E. J. , Rossomando E. F. 
Published: June 2005

AbstractMesenchymal cells isolated from the papilla of embryonic tooth germs of the mouse were cultured in a complex medium for five to six days. Liquid nitrogen lysates, prepared from these cells, incorporated nucleoside monophosphates into a cold acid‐insoluble product. The product was sensitive to RNase and no product was formed if the lysate was pretreated with DNase. The reaction was sensitive to EDTA and, in its presence, optimum activity was obtained with 2 mM MgCl2. On sucrose gradients, the reaction product was distributed between two broad peaks; one centered about 18S and the other above 28S. The RNA polymerase inhibitor α‐amanitin inhibited approximately 50% of the activity at a concentration of 10 μg/ml.
Metabolic consequences of accelerated urea synthesis during seasonal dormancy of spadefoot toads, Scaphiopus couchi and Scaphiopus multiplicatus
Authors: Jones Ronald M. 
Published: June 2005

AbstractScaphiopus couchi newly emerged from natural dormancy produce urea at a greater rate than dormant toads kept in moist soil. Energy budgets during dormancy of Scaphiopus couchi and S. multiplicatus were calculated by measuring protein, carbohydrate, lipid, ash, and DNA content of newly emerged toads and toads near the end of the natural activity period. Scaphiopus couchi uses 17% of the protein, 36% of the lipid, and 28% of the total energy reserves available at the start of dormancy, and S. multiplicatus uses 32% of the protein, 62% of the lipid, and 51% of the total energy reserves. If all of the nitrogen derived from protein catabolism were accumulated as urea, the minimum difference in body fluid concentrations before and after dormancy would be 167 mM for S. couchi and 341 mM for S. multiplicatus. Because these predicted increases are greater than normally observed in the body fluids of spadefoots at the end of dormancy, the toads apparently are obtaining sufficient part of their nitrogen wastes. Simultaneous O2 consumption, CO2 production, and nitrogen waste production measurements provide evidence for a shift from lipid to protein metabolism in S. couchi when osmotically stressed. During osmotic stress, S. couchi does not simultaneously achieve the reduced levels of O2 consumption associated with dormancy, and increased protein catabolism and urea synthesis. Feeding experiments show that protein, carbohydrate, and lipid and replenished in newly emerged. S. couchi in proportion to their representation in the diet.
Volume changes associated with hydrolysis of ATP by teleost branchial (Na+ + K+)‐ATPase and Mg2+‐ATPase
Authors: Pfeiler Edward 
Published: June 2005

AbstractThe effects of hydrostatic pressure on branchial NaK‐ATPase and Mg‐ATPase activities of Scorpaena guttata (shallow‐water fish) and Anoplopoma fimbria (deep‐water fish) were used to calculate volume changes that occur during catalysis. The apparent activation volumes (ΔVs) of the NaK‐ATPase, determined at test pressures between 68 and 340 atm, were positive and not significantly different in the two species. ΔV for the Mg‐ATPase of S. guttata was also positive but significantly lower than the ΔV value for the NaK‐ATPase. Negative values for ΔV were obtained for the Mg‐ATPase of A. fimbria. Solubilization of the enzymes from gill microsomes of A. fimbria with Lubrol WX had no effect on ΔVs. NaI treatment of gill microsomes resulted in significant changes in ΔV for both enzymes in A. fimbria and in the Mg‐ATPase of S. guttata. The effect of hydrostatic pressure on Kmfor ATP was used to estimate apparent ATP binding volume (ΔVbind.). The Km values obtained at 1 atm for the Mg‐ATPase and NaK‐ATPase of A. fimbria (0.030 and 0.043 mM, respectively) were approximately an order of magnitude lower than those of S. guttata(0.24 and 0.28 mM, respectively). High hydrostatic pressure (340 atm) produced an increase in Km in the NaK‐ATPase of both species, indicating that ΔVbind. is positive. The Km of the Mg‐ATPase in S. guttata was relatively insensitive to pressure (small positive value for ΔVbind.) where it decreased at high pressure in A. fimbria, yielding a large negative value for ΔVbind..
A technique for the in vitro perfusion of bovine parathyroid glands
Authors: Latmen Neal S. 
Published: June 2005

AbstractA system for the in vitro perfusion of bovine parathyroid glands was developed. The glands were perfused at 1 ml/minute with oxygenated Hanks balanced salt solution buffered with sodium bicarbonate to a pH of 7.4 at 37°C. These glands remained functionally stable for seven to eight hours. The secretory rate of immunoreactive parathyroid hormone varied inversely with the calcium concentration of 3.0 to 6.0 mg/100 and became nonsuppressible at calcium concentrations above 6.5 mg/100 ml. Therefore, the glands are thought to be responsive to stimuli. A loss of functional stability can usually be detected by an increase in perfusion pressure. The samples of effluent containing immunoreactive parathyroid hormone remained stable (immunoreactively) for six months when stored at −70°C. This system provides a valid method for monitoring dynamic, minute‐to‐minute changes in parathyroid secretory activity.
Changes in protein synthesis following fertilization of the mouse ovum
Authors: Chen H. Y. , Brinster R. L. , Merz E. A. 
Published: June 2005

AbstractA quantitative method utilizing double isotope labeling with 3H‐methionine and 35S‐methionine and two‐dimensional polyacrylamide gel electrophoresis was employed to compare synthesis of 95 individual proteins in fertilized and unfertilized mouse ova. It was found that six proteins had significantly (P < 0.05) increased rates of synthesis while 11 proteins had significantly (P < 0.05) decreased rates of synthesis following fertilization. The studies indicate that there are changes in the synthetic rates of a much larger number of proteins at the time of fertilization than expected from previous reports.
Catalyic and regulatory properties of muscle pyruvate kinase from Cancer magister
Authors: Guderley Helga , Hochachka Peter W. 
Published: June 2005

AbstractDespite the marked changes that crustacean muscle undergoes during the molt cycle, pyruvate kinase is present as the same from throughout the molt cycle. This pyruvate kinase was subject to feed‐forvard activation by fructose‐1, 6 bisphosphate (FBP) as well as feed‐back inhibition by MgATP. The enzyme showed a high affinity for phosphoenolpyruvate (Km = 0.1 mM) but showed no cooperativity in substrate binding. The addition of 0.05 mM FBP reduced the PEP Km to 0.05 mM. MgATP inhibition showed a Ki of 1.8 mM versus PEP. The inhibition due to MgATP could be reversed by FBP. Various other compounds inhibited the enzyme, including citrate, α‐ketoglutarate, tryptophan, and malate, although at rather high levels. Measurements of the reversal of this pyruvate kinase, taken together with the low levels of phosphoenolpyruvate carboxykinase and pyruvate carboxylase, predict only minimal levels of gluconeogenic flux in crustacean muscle.
Active calcium extrusion by Amoeba proteus
Authors: Prusch Robert D. 
Published: June 2005

AbstractCytoplasmic calcium levels in the amoeba are maintained at very low levels. Previous studies have suggested that this is accomplished by a system of cytoplasmic storage sites. Evidence is presented here that Amoeba proteus capable of actively extruding calcium across the plasmalemma. Active calcium extrusion is then responsible in part for the maintenance of low cytoplasmic calcium activities and may be involved at least indirectly in such basic cellular process as locomotion and pinocytosis in the amoeba.
Some observations on the sex differentiation of an entoproct, Barentsia discreta (Busk)
Authors: Mukai Hideo , Makioka Toshiki 
Published: June 2005

AbstractThe differentiation of sex and the morphology of gonads of a colonial entoproct Barentsia discreta were studied with living animals and histological preparations. Each zooid is unisexual; the colony is monoecious, containing both male and female zooids. During the early part of the breeding season, male zooids exceed female zooids in number. Even at the peak period (August and September), male zooids are predominant along the distal portions of actively growing stolons. When the calyx of a zooid is replaced through regeneration, a change of sex may occur. Some double monsters with a male and a female calyx were found. In both sexes, the reproductive system consists of a pair of gonads and a common gonoduct. In the male, the spermiduct is surrounded by some atrophied glandular cells. At the junction of the testis and the spermiduct, some epithelial cells are specialized to bear long cilia, which are extended into the testicular lumen. Immature testes often contain some previtellogenic oocytes. In the female, the oviduct is accompanied by glandular cells and is divided distally into a pair of small ducts. The small oviduct connects with the ovary by a large cell, called the “plug”‐cell. The largest oocytes occupy the blind end of the ovary, where the ovarian tissue contains many mature spermatozoa. The egg becomes fertilized in the ovary and is ovulated at the metaphase of the first meiotic division. Polar body formation and subsequent embryogenesis proceed in the vestibule. Seven or eight days seem to be needed from ovulation to larval release.
Further evidence for haploid gene expression during spermatogenesis: Heterogeneous, poly(A)‐containing RNA is synthesized post‐meiotically
Authors: Erickson Robert P. , Erickson Jeanne M. , Betlach Charles J. , Meistrich Marvin L. 
Published: June 2005

AbstractMouse testicular cells labelled in vivo with 3H‐uridine for 1 hour were separated into enriched cell populations representing different stages of spermatogenesis by centrifugation in an Elutriator rotor. RNA extracted with phenol and chloroform was sized by electrophoresis on 2.4% acrylamide gels. The percentage of newly synthesized RNA which was not ribosomal RNA (or its precursors) and was not transfer RNA, was higher in early postmeiotic, as compared to late premeiotic, stages. RNA was also extracted from fractionated cells in the presence of guanidinium chloride and the proportion of total 3H‐RNA‐containing poly(A) sequences was determined by binding to an oligo‐(dT)‐cellulose column. RNA that bound in 0.5 NaC1 was eluted with low salt buffer and reapplied twice more, after heating each time in DMSO to disaggregate any non‐poly(A)‐containing RNA. The percentage of newly synthesized RNA which contained poly(A) did not decrease in early postmeiotic, as compared to late premeiotic, stages. We suggest that at least some part of the 6–15S 3H‐RNA and 3H‐poly(A)‐containing RNA represents mRNA(s) transcribed postmeiotically in haploid germ cells.
Influence of temperature and unstirred layers on the kinetics of glycine transport in isolated gills of Mytilus californianus
Authors: Wright Stephen H. , Becker Steven A. , Stephens Grover C. 
Published: June 2005

AbstractThe effect of temperature on the kinetics of glycine influx in isolated gills of Mytilus californianus was studied. Increases in temperature resulted in significant increases in the J for glycine influx over the range 7–23° C (Q10 = 5). Concomitant with this increase in J was an increase in experimentally determined Kt, from 23 μM to 134 μM. The relationship between changes in J and measured Kt was adequately described by an equation that takes into account the influence of unstirred layers on the kinetics of carriermediated transport. Use of this equation indicated that the changes in measured Kt could be explained by the presence of an unstirred layer approximately 400 μm thick over the transporting surfaces(s) of the isolated gill, and that the “true” Kt of the transport process is 1 μM. The very low values Kt for amino acid uptake measured in intact mussels (1–3 μM) are revealed to be the product of transport processes of high affinity for substrate and a perfusion system which effectively minimizes the influence of unstirred layers, thereby permitting efficient utilization of substrate at the low concentrations characteristic of these animals' environment.
Fluorometric detection of implantation sites in rats
Authors: Hicks J. J. , Gil‐Recasens M. E. , González‐zamudio J. 
Published: June 2005

AbstractA new fluorescent technique is proposed for detecting implantation sites in the rat, based on the binding capacity of tetracycline. Both intraluminal (20 μg/kg) and intravenous (8.3 mg/kg) administrations of tetracycline permit the macroscopic visualization (under 366 nm of ultraviolet light) of implantation sites, since they show a lower flurescence (LFS) than the remaining endometrium (FS). Greater binding a tritiated tetracycline was observed in nonimplantation sites (176 to 56 × 103 dpm/mg protein) than in implantation sites (P < 0.05).
Initiation of cleavage in Oryzias latipes eggs injected with centrioles from sea urchin spermatozoa
Authors: Ohta T. , Iwamatsu T. 
Published: June 2005

AbstractCleavage‐initiating activity of various biological materials was tested by microinjection into unfertilized eggs of Oryzias latipes. Injection of intact sea urchin spermatozoa, their flagellum‐ and centriole‐fractions induced cleavage of unfertilized eggs. On the contrary, injection of the suspension medium alone did not induce cleavage. In the process of a ster formation elicited by injection, fibrous structures appeared first within a dispersing mass of the injected fraction, and they then developed into a few large or many small astral structures. Eggs which cleaved within 2 hr after injection displayed only a few large asters within a thickened blastodisc. In the non‐cleaved eggs, only many small asters appeared throughout the blastodisc.These experiments indicated that the isolated centrioles from sea urchin spermatozoa can induce aster formation and cleavage in the fish.
Role of neural retina and vitreous body during lens regeneration: Transplantation and autoradiography
Authors: Gulati Adarsh K. , Reyer Randall W. 
Published: June 2005

AbstractThe trophic influence of neural retina in regeneration of the lens from dorsal iris is well known. The first part of this study involved transplantation of dorsal iris pieces into various intra‐ocular positions in order to determine the field of action of the neural retina. The most favorable location for lens regeneration was the pupillary space, closely followed by the vitreous chamber. Lens regeneration was retarded from implants lying in the anterior chamber; this was most evident when grafts were placed in front of the iris and not in contact with the swollen vitreous body. Incorporation of 3H‐leucine in the neural retina and vitreous body was also investigated using autoradiography. No significant difference in labeling was seen between the control and lentectomized neural retina at all time intervals studied. However, increased labeling above that in the controls was observed over the vitreous body between 8 to 20 days after lentectomy. There was also an increase in the number of silver grains over the vitreous body with increasing time between injection of isotope and sacrifiec of the animal. These results provide evidence that vitreous body plays an important role in the process of lens regeneration, perhaps serving as a preferential pathway for transfer of the neural retinal factor to the dorsal iris.
Sperm maturation and the formation of sperm pairs in the epididymis of the opossum, Didelphis virginiana
Authors: Temple‐Smith P. D. , Bedford J. M. 
Published: June 2005

AbstractDidelphis spermatozoa released from different levels of the epididymis exhibit a series of changes that reflect events involved in the process of their maturation. Their progression through the duct is accompanied by a rotation of the sperm head on the axis of the tail, by an eccentric movement of the cytoplasmic droplet to the anterior region of the midpiece from where it is discarded, by appearance in the posterior midpiece of regular submembranous electron‐dense ridges, and by visible condensation of the mitochondrial cristae and matrix. The latter seems to correlate generally with onset of the ability for progressive motility acquired by most spermatozoa as they reach the lower corpus epididymidis. This phase is associated also with the beginnings of the pairing by the acrosomal surface that characterizes mature spermatozoa of New World marsupials. Use of lectins and cationized ferric colloid as affinity markers served to reveal changes occurring also in the character of the sperm head and tail surface prior to pairing.This investigation strengthens the idea gained from previous study of an Australian marsupial, Trichosurus, that the complexity of sperm maturation in the epididymis of Metatheria is broadly comparable to that observed in most eutherian mammals.
The environmental control of hatching in Fundulus heteroclitus
Authors: Dimichele Leonard , Taylor Malcolm H. 
Published: June 2005

AbstractSalinity, pH, dissolved oxygen, hydration, and temperature were examined as possible environmental cues that might intiate hatching in Fundulus heterolitus. Incubation in or transfer to water adjusted to ranges of salinity, pH, and temperature within the physiological range of the species had no direct effect on hatching. Eggs incubated in water with dissolved oxygen concentrations greater than 6 ml O2/L or solutions of Carbowax PEG 4000 producing an osomotic flux of water out of the eggs delayed hatching indefinitely. Incubation of eggs in air delayed hatching, regardless of the pO2. Eggs delayed for periods of up to 1 mo by incubation in air or in highly oxygenated water hatched normally when placed in water of 4 ml O2/L or less. Additionally, eggs that were partially dehydrated by incubation in air did not hatch when placed in a pressurized container of mineral oil. These results indicate that both water and low dissolved oxygen concentration are necessary for hatching to occur. Both of these conditions are likely to exist in the field when stranded eggs are immersed in water.
Diurnal changes in mouse mammary gland DNA synthesis
Authors: Borst David W. , Mahoney William B. 
Published: June 2005

AbstractDNA synthesis was studied in mammary tissue from 13‐ and 15‐day pregnant Balb/c mice at different times during the day. Tissue was labeled with 3H‐thymidine (3H‐TdR) using both in vivo and in vitro techniques. The labeling index of mammary epithelial cells was determined by autoradiography. Incorporation of 3H‐TdR into TCA‐precipitable material after in vitro labeling was also measured. The labeling index of mammary alveolar cells is 2.5 times higher in tissue from animals studied at midnight when compared to tissue from animals studied at noon; ductal epithelial cells do not show any variation in labeling index at these time periods. Precursor incorporation into TCA‐precipitable material is also increased at midnight when compared to values at noon. Tissue from animals at 6 A. M. and 6 P. M. show intermediate levels of 3H‐TdR incorporation when measured by both of these methods. Diurnal variations in DNA synthesis in mammary tissue may reflect daily changes in either serum levels of those hormones directly stimulating this process or fluctuations in tissue sensitivity to these hormones, and might provide a means of analyzing the regulation of mammary epithelial cell proliferation during pregnancy.
The effects of α‐amanitin and cordycepin on vitellogenin synthesis by mosquito fat body
Authors: Kaczor W. J. , Hagedorn H. H. 
Published: June 2005

AbstractVitellogenin synthesis by mosquito (Aedes aegypti) fat body is stimulated by incubation with ecdysterone. α‐amanitin and cordycepin prevent the response to ecdysterone. These results support the hypothesis that ecdysterone regulates vitellogenin synthesis at the transcriptional level.
Analysis of yolk syncytium behavior in Salmo and Catostomus
Authors: Long Wilbur L. 
Published: June 2005

AbstractThe formation and early behavior of the yolk syncytial layer (YSL) of selected representatives of the teleost orders Clupeiformes and Cypriniformes are described, contrasted, and correlated with normal embryonic staging sequences. Movements of the cytoplasmic syncytium in Catostomus commersoni have been mapped by implantation of chalk particles and correlated with the morphogenetic movements of the blastodisc. The chalk particle experiments show for the first time that YSL cytoplasm which reaches the yolk plug during epiboly is not a part of the syncytium when gastrulation begins. Furthermore, there is a distinct convergence of YSL cytoplasm toward the dorsal midline during epiboly which mimics the motion of the cells at this time.