bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro fertilization of rat and mouse eggs by ejaculated sperm and the effect of energy sources on in vitro fertilization of rat eggs
Authors: Tsunoda Y. , Chang M. C. 
Published: June 2005

AbstractIn vitro fertilization of rat and mouse eggs by ejaculated or epididymal spermatozoa in chemically defined media was studied. Penetration rates by ejaculated sperm was very low (0 to 8%) in the rat, but 11 to 41% of eggs were penetrated by ejaculated sperm in the mouse. The optimal concentration of sperm for in vitro fertilization appears to be similar whether ejaculated or epididymal sperm were used. The time of sperm penetration in the mouse eggs, however, was delayed for one‐half to one hour when ejaculated sperm were used.The importance of sodium pyruvate, sodium lactate and glucose in the medium containing bovine serum albumin for in vitro fertilization of rat eggs was examined. When rat eggs in cumulus clot were exposed to epididymal sperm preincubated for five hours, the presence of sodium pyruvate, sodium lactate and glucose was found to play an important role. When exposed to non‐incubated epididymal sperm sodium pyruvate could be omitted without much decline of the fertilization rate. When the denuded eggs were exposed to non‐incubated sperm, penetration rates were very low (0 and 5%) in the absence of pyruvate. It appears that although lactate, pyruvate and glucose are all important for in vitro fertilization of rat eggs, pyruvate can be supplied by the follicular cells surrounding the eggs.
Tooth replacement in the upper jaw of the rainbow trout (Salmo gairdneri)
Authors: Berkovitz B. K. B. , Moore M. H. 
Published: June 2005

AbstractThe present paper describes the pattern of tooth replacement in the upper jaw of two size ranges of rainbow trout (standard lengths 12–15 cm and 20–23 cm) as determined from wax impressions of the dentitions taken twice weekly on anaesthetised fish. There was considerable variation in the nature of replacement waves (lines constructed on dental charts linking eruption times of alternate teeth) between fish for both the premaxillary/maxillary and vomerine/palatine rows. The wave patterns obtained showed the same consistency of form for any one animal which is to be expected when consecutive generations show constant or proportionately changing life spans. Data relating to the life span of the teeth is given. The results are compared with those derived for the lower jaw and the significance of wave form discussed.
In vitro development of t6/t6 embryos
Authors: Erickson Robert P. , Pedersen Roger A. 
Published: June 2005

AbstractEmbryos from matings in which approximately a third of the zygotes were expected to be t6/t6, a condition known to be lethal at the egg cylinder stage in vivo, were compared to normal control embryos during post‐implantation culture. The percentage success of trophoblast out growths was the same in both groups while the experimental group showed a 25% deficiency of embryos with inner cell masses. Those experimental embryos which did have inner cell masses developed comparably to the control group and both groups showed roughly similar numbers of morphologically abnormal egg cylinders. Autoradiography disclosed no deficiency in 3H‐thymidine and 3H‐uridine labeling in disorganized egg cylinder embryos.
Synthesis of octopamine by insect dorsal median unpaired neurons
Authors: Hoyle Graham , Barker David L. 
Published: June 2005

AbstractDorsal unpaired median (DUM) neurons of locusts and grasshoppers inhibit the instrinsic rhythm of contraction of metathoracic extensor tibia muscle fibers. This physiological action is mimicked by very low concentrations of octopamine and by higher concentrations of dopamine and noradrenaline. We have examined the synthesis of biogenic amines from tritiated tyrosine by these neurons. DUM cell bodies and a peripheral nerve containing the DUM axon which terminates in the extensor tibia both produced octopamine, but neither noradrenaline nor dopamine synthesis was detected. The observations support the suggestion that the dorsal unpaired median neurons are octopaminergic.
Normal development of the chick wing following removal of the polarizing zone
Authors: Fallon John F. , Crosby Gayle M. 
Published: June 2005

AbstractThe negative results of assays for polarizing activity along the posterior border of the chick wing 24 and 48 hours after removal of the polarizing zone demonstrate that this zone is not regenerated following removal. These results, and the fact that normal wing development can occur after polarizing zone removal from stages 15 through 24 wing buds, indicate that during these stages the polarizing zone has no direct role in normal development of the limb bud. It isspeculated that the polarizing zone is effective only during limb induction and that after this time it exists latentor residual form.
Purification and molecular properties of the (sodium + potassium)‐adenosinetriphosphatase and reconstitution of coupled sodium and potassium transport in phospholipid vesicles containing purified enzyme
Authors: Hokin Lowell E. 
Published: June 2005

AbstractRecent work in our laboratory on the purification and characterization of the (sodium + potassium)‐activated adenosinetriphosphatase (NaK ATPase) has been reviewed. Two enzymes have been purified, that from the rectal salt gland of the spiny dogfish, Squalus acanthias and that from the electric organ of the electric eel, Electrophorus electricus. The enzyme appears to consist of two catalytic subunits of molecular weight of about 95,000 and one glycoprotein with a molecular weight of about 50,000. The amino acid composition, N‐terminal amino acids, and the carbohydrate composition of these subunits have been determined. The phospholipid composition of the holoenzyme has also been determined. The protein component shows very little variation with evolution, but the carbohydrate and phospholipid components show considerable variation. It has been possible to form vesicles from the purified enzyme from Squalus acanthias and to demonstrate the ATP‐dependent, ouabain inhibitable, coupled uphill transports of Na+ and K+. The properties of these transports are very similar to those observed previously in intact erythrocytes or resealed erythrocyte ghosts with respect to asymmetries of binding sites, stoichiometries of Na+ and K+ transported, Na+−Na+ exchange, and K+−K+ exchange. It is concluded that the NaK ATPase is the molecular machine for effecting Na+ and K+ transport in the intact cell membrane.
Comparative physiology of cellular ion and volume regulation
Authors: Schmidt‐Nielsen Bodil 
Published: June 2005

Abstract
Intracellular [K+]i in most cells is around 100–150 mOs. This is true in invertebrate or vertebrate muscle or any other tissue, and the only known exceptions being the axons of some invertebrates (Burton, '73).
When cell volume is increased due to hypoosmotic swelling, cell volume is regulated back toward normal in almost all cells. In cells with an osmolality of 300–350 mOs, the regulatory volume decrease is caused primarily by a passive efflux of potassium and anions due to increased membrane permeability to potassium. In cells with a higher osmolality, regulatory volume decrease is caused by the passive efflux of small organic molecules.
When cell volume is decreased due to hyperosmotic shrinking, volume is not always regulated back toward normal in in vitro experiments carried out for several hours. However, it appears from the in vivo experiments that some cell volume control is always present. The volume control in the flounder red cells took place through increased sodium influx brought about by a relative increase in cell membrane permeability to sodium. This mechanism also appears to be dominant in the mammalian renal papilla, where the [Na+]i increases in proportion to the increase in cellular osmolality with no change in [K+]i.
Cells which remain shrunken in vitro, or cells which only partly restore their volume in vivo, do not exhibit increased [K+]i. This finding means that potassium is lost from the cell and, in most cases, exchanged for sodium when the volume is decreased, even though the osmotic concentration in the extracellular fluid is elevated.
Finally, it appears that the maintenance of a rather constant [K+]i is important for all cells. This constancy may be due to the fact that certain enzymes are sensitive to the intracellular potassium concentration. Thus, the DNA synthesis is blocked in mammalian kidney cells when [K+]i is increased (Bygrave, '67). Furthermore, Lubin ('64) has shown that low [K+]i concentrations also cause a decrease in DNA, RNA, and protein synthesis. An optimal concentration appears to be necessary for protein synthesis.
Versatility of hydraulic systems
Authors: Chapman G. 
Published: June 2005

AbstractThe use of fluid or easily deformable materials for force transmission in a variety of animals is reviewed and its role in muscular antagonism is shown. The hydraulics of cells and developing embryos is mentioned and animals employing hydraulic systems are classified as having open, closed or external fluid compartments and simple or complex muscular arrangements. The importance of hydraulically antagonized muscle systems in movement and locomotion is described, and the application of force to the substratum discussed, including the concentration of force from a large muscle field on a smaller area of application. The jet propulsion of cephalopods and medusae is described and their short time scale of action is compared with the long time scale of operation of other hydraulic systems. The pumping operation of the nematode pharynx, the mechanism of suctorial feeding in insects and the energetic demands of tube irrigation in feeding are outlined.
Cell proliferation in the digestive tract of Styela clava (Urochordata: Ascidiacea) as revealed by autoradiography with tritiated thymidine
Authors: Ermak Thomas H. 
Published: June 2005

AbstractThe DNA‐synthesizing cells in the digestive tract of Styela clava were labeled with tritiated thymidine and detected at increasing time intervals with autoradiography. Most of the epithelia consist of renewing cell populations. These are the dorsal tubercle, dorsal lamina, branchial bars, zone 1 of the endostyle, stigmata, esophagus, stomach, intestine, and rectum. Expanding populations are the branchial tentacles, unspecialized pharyngeal cells, and pylorictubules. In the renewing populations, cell proliferation occurs in restricted germinal zones of pseudostratified cells. In the postbranchial digestive tract, these germinal zones usually occur at the bases of folds or grooves. Germinal cell nuclei migrate into the cell apex and undergo mitosis there. With time, germinal cells migrate as a band of labeled cells over the underlying connective tissue into non‐proliferating mature zones of ciliated, secretory, or absorptive cells. Aging mature cells are presumably extruded into the gut lumen, maintaining the system in a steady state. Transit times are about ten days for the stigmata; two and a half weeks for the dorsal tubercle, esophageal mucous population, stomach crest population, and stomach groove population; five weeks for the intestine and rectum; and several months for zone 1 of the endostyle and esophageal band population.
The ubiquitous occurrence of chondroitin sulfates in chick embryos
Authors: Abrahamsohn Paulo A. , Lash James W. , Kosher Robert A. , Minor Ronald R. 
Published: June 2005

AbstractThe synthesis of sulfated glycosaminoglycans has been studied in a wide variety of embryonic chick tissues. All tissues studied have the capability to manufacture, but not necessarily accumulate, the chondroitin sulfates as well as other glycosaminoglycans. The relative distribution of glycosaminoglycans differs between tissues and changes with age.
Annual cycle of plasma luteinizing hormone concentrations in wild mallard drakes
Authors: Haase E. , Sharp P. J. , Paulke E. 
Published: June 2005

AbstractPlasma LH concentrations were followed in 9 individually marked wild mallard drakes in Kiel (54°N) for one year at monthly intervals. Mean LH levels increased during the spring and reached the annual maximum in April and May. In June when testicular regression occurs, the LH titer sharply decreased and was lower than at any other phase of the annual cycle. In late fall mean plasma LH concentrations increased and, whilst not reaching the values observed during the breeding season, remained relatively high during the winter. Thus, in the mallard LH can be released under short and long daily photo‐periods.
Regulation of the oxidative NADP‐enzyme tissue levels in Drosophila melanogaster. I. Modulation by dietary carbohydrate and lipid
Authors: Geer B. W. , Kamiak S. N. , Kidd K. R. , Nishimura R. A. , Yemm S. J. 
Published: June 2005

AbstractWild‐type third instar larvae of Drosophila melanogaster fed a casein‐sucrose synthetic diet supplemented with phosphatidylcholine (4 mg/ml) possessed 33% more tissue lipid and a modified fatty acid profile compared to larvae fed a fat free‐sucrose diet. The rates of lipid synthesis and pentose shunt activity were 2.1 and 2.2 times greater respectively in larvae fed the fat free‐sucrose diet than in fat‐sucrose fed animals. The tissue concentrations of acetyl‐CoA and acytl‐CoA were 80 and 61% higher respectively, CoA 49% lower, and the NADPH/NADP+ ratio greater in fat‐sucrose fed larvae than in larvae fed a fat free‐sucrose diet. Thus, larvae effectively utilized dietary lipid for lipid synthesis and as a supplementary energy source to carbohydrate. Larval oxidative NADP‐enzyme tissue levels were dependent upon the interaction of at least three regulatory systems. Dietary carbohydrate induced high tissue levels of glucose‐6‐phosphate dehydrogenase (EC 1.1.1.49) and 6‐phospho‐gluconate dehydrogenase (EC 1.1.1.43), ostensibly via a glycolytic derivative. High tissue levels of malic enzyme (EC 1.1.1.40) and NADP‐isocitrate dehydrogenase (EC 1.1.1.42) were induced by an acetate derivative postulated to be formed by the Krebs cycle. In contrast, a fatty acid derivative, presumably a product of β‐oxidation, repressed the tissue levels of all four oxidative NADP‐enzymes in larvae. A model of induction and repression regulatory systems that are dependent on regulatory gene products is proposed.
Variation in the effects of antidiuretic hormone on the isolated skin of the toad, Scaphiopus couchi
Authors: Hillyard Stanley D. 
Published: June 2005

AbstractThe rate of active sodium transport as measured by short‐circuit current across the isolated skin of the toad, Scaphiopus couchi, was elevated following vasopressin (0.2 units/ml) or arginine vasotocin (0.1 units/ml) treatment of skins from active animals at all times of the year tested. Skins from dormant animals showed no such elevation at any time of the year. The rate of active sodium transport was elevated following treatment with dibutyryl cyclic AMP (2.5 mM) plus theophylline (10 mM) in all skins tested.The hydraulic conductivity of isolated skins from both active and dormant animals showed no significant change following treatment with vasopressin (0.2 units/ml) or arginine vasotocin (0.1 units/ml) except on the first day following emergence from dormancy in the field. A correlation was, therefore, observed between the occurrence of a hydroosmotic response to antidiuretic hormones and the seasonal exposure of S. couchi to standing water.A small but significant elevation of hydraulic conductivity was observed across the skins of dormant toads following treatment with dibutyryl cyclic AMP (2.5 mM) plus theophylline (10 mM) whereas a substantial elevation was observed with the skins of active animals.
Hormone induction of specific protein synthesis in midpregnant mouse mammary cell culture
Authors: Ceriani Roberto L. 
Published: June 2005

AbstractMonolayer primary cell cultures of midpregnant mouse mammary cells were subjected to hormone stimulation under strictly defined conditions. Hormonal response was measured in terms of increase in rate of synthesis of mouse casein, using a double antibody precipitation technique. Cells stimulated by insulin plus prolactin plus cortisol plus estradiol plus progesterone showed a marked increase in rate of mouse casein synthesis over the controls. This specific product synthesis, which remains inducible in these cells for at least ten days, was detected either by labelled phosphoric acid or labelled amino acid incorporation. The mouse casein synthesized was identical, as judged by the identification techniques used, to that of mouse milk.Mouse midpregnant mammary explants in organ culture require insulin plus prolactin plus cortisol to express their full lactogenic capabilities. Nevertheless, when the same cells are dispersed and grown in monolayers they require ovarian steroids to elicit a lactogenic response as shown in this study. Ovarian steroids, therefore, are necessary in lactogenesis, although the fundamental nature of their action remains to be established.
Ventilation and metabolic rate of young rainbow trout (Salmo gairdneri) exposed to sublethal environmental pH
Authors: Hargis Jack R. 
Published: June 2005

AbstractDifferences between ventilatory response and metabolic rates of young rainbow trout tested within the sublethal range of pH 6 to pH 9 were observed using a flowing water respirometer. The oxygen consumption was monitored at swimming speeds of 12 cm/sec and 24 cm/sec. The oxygen consumption rates at 24 cm/sec and pH 6 (423 mg/kg‐hr) and pH 9 (367 mg/kg‐hr) were considerably higher than those determined near neutrality (328 mg/kg‐hr). Ventilation rate increased to either side of neutrality, but significantly fewer respiratory reversals, or “coughs,” were obseved at pH 6 and a greater number at pH 9 than occurred at pH 7 and 8 or in untested fish. The respiratory‐cough response is shown to be pH‐dependent in rainbow trout and may therefore not be as reliable an indication of pollutant‐caused stress in studies where the experimental pH has not been specified or controlled.
The role of the copulatory plug in reproduction of the guinea pig
Authors: Martan Jan , Shepherd Benjamin A. 
Published: June 2005

AbstractTwo methods of artificial insemination and removal of copulatory plugs were used to investigate the role of the plug in the guinea pig. In addition, the effectiveness of the copulatory plug in blocking the passage of spermatozoa from the second mating was tested in albino females, where coat color was used as a genetic marker.Thirteen female guinea pigs that were either in proestrus, estrus, or metestrus, and inseminated with freshly collected copulatory plugs containing living spermatozoa, did not conceive. In a group of six females from which the copulatory plug was immediately removed, five conceived. Of nine estrous females artificially inseminated, five conceived. In five albino females, copulatory plugs from albino males completely blocked spermatozoa deposited by colored males, and 20 offspring, all albino were born. In a second group of four albino females where the plugs of albino males were removed prior to copulation with colored males, resulting litters were sired by either male or a combination of both males.
Maturation and sperm penetration of canine ovarian oocytes in vitro
Authors: Mahi Cherrie Ann , Yanagimachi Ryuzo 
Published: June 2005

AbstractCanine ovarian oocytes were cultured in a medium consisting of TC medium 199, fetal calf serum and antibiotics. Ninety‐nine percent of the apparently healthy oocytes were in the germinal vesicle (dictyate) stage when recovered from the ovaries; 25% of them reached metaphase I or II by 72 hours of culture. Washed ejaculated spermatozoa were added to BWW medium containing oocytes which had either been removed directly from the follicles or which had been cultured for 24‐72 hours. The earliest acrosome reaction and zona penetration by spermatozoa were seen at seven hours after insemination. Seventy‐four percent of the oocytes examined between 11 and 24 hours after insemination showed evidence of zona penetration by spermatozoa. Neither the condition of the oocyte vitellus nor the stage of nuclear maturation influenced the incidence of zona penetration. Decondensing sperm nuclei were found in the vitellus of 27% of the oocytes which had not been cultured and in the vitellus of 20% of those which had been cultured for 24–72 hours and were in various stages of maturation. These results indicate that (1) canine ovarian oocytes can be matured in vitro, (2) the spermatozoa require capacitation which takes approximately seven hours in vitro and (3) maturation of the oocytes is not required for sperm passage through the zona pellucida or entry into the vitellus nor for sperm nuclear decondensation.
Regeneration from different levels along the tail of the newt, Notophthalmus viridescens
Authors: Iten Laurie E. , Bryant Susan V. 
Published: June 2005

AbstractSome aspects of the influence of position on regeneration have been examined by comparing regeneration from different levels along the newt tail. Tails amputated such that either three‐fourths, one‐half or one‐fourth of the tail was removed pass through the same morphological and histological stages at the same times after amputation. In tails amputated at these three different levels, the rate of elongation of regenerates from more proximal levels is greater than that of regenerates from more distal levels. The total lengths of regenerates from different levels are proportional to the lengths of tail removed by amputation. Furthermore, the number of vertebrae formed in a tail regenerate is directly proportional to the number of vertebrae removed by amputation. When a tail blastema is transplanted to a more proximal level tail stump, intercalary regeneration between the stump and transplant occurs and the resulting regenerate has a complement of vertebrae appropriate to its new level along the tail. The results indicate that position along the appendage does not influence the developmental sequence of events of regeneration, but that it does influence the rate of growth and the structures to be replaced.
Duration of the cycle of the seminiferous epithelium in the prairie vole (Microtus ochrogaster ochrogaster)
Authors: Schuler Harold M. , Gier Herschel T. 
Published: June 2005

AbstractThe cycle of the seminiferous epithelium in M. o. ochrogaster was divided into eight readily recognizable stages based on the morphology of the developing spermatid. The mean relative frequencies of Stages I through VIII were 11.66, 19.25, 20.00, 19.00, 8.42, 6.17, 9.25 and 6.58%, respectively.The duration of one cycle of the seminiferous epithelium in this species, as determined from autoradiographs of thymidine‐H3 injected testes was 7.17 days (S.E. ± 0.03). This is the shortest spermatogenic cycle reported for any mammal to date. The approximate durations of the meiotic prophase, meiotic divisions, and spermiogenesis were 8.8, 0.4 and 12.2 days, respectively. The entire process of spermatogenesis was estimated to span approximately 28.68 days.The number of cycles that spermiogenesis spanned in this species was compared to values calculated for other species. Values within groups of related species appear relatively constant, but between groups the values are variable.