bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capacitation of boar spermatozoa: Synergism between uterine and tubal environments
Authors: Hunter R. H. F. , Hall J. P. 
Published: June 2005

AbstractThe influence of the site of semen deposition on the rate of sperm capacitation was studied in 36 oestrous gilts in which ovulation had been induced at a precise time. Aliquots of semen were instilled into the proximal uterine horn on one side of the tract and into the isthmus of the contralateral Fallopian tube in 24 animals. Eggs were recovered in vivo, and examined by phase‐contrast microscopy for the number of spermatozoa associated with the zona pellucida and the stage of fertilization.A total of 420 eggs was examined. The mean number of spermatozoa per egg increased from 3.3 at four hours after uterine insemination to 27.9 at six hours, compared with 0.6 to 6.3 at corresponding intervals after tubal insemination (p<0.05). The mean proportion of fertilized eggs increased from 54.3% at four hours to 95.9% at six hours after uterine insemination, compared with 0.0 to 51.0% at these intervals after tubal insemination (p<0.001). The temporal advantage accruing from uterine insemination was also seen in the developmental stages of the penetrated eggs. In a further six animals in which seminal plasma was introduced into the isthmus at the time of uterine insemination, fertilization was retarded by approximately two hours, although when a similar volume of physiological medium was introduced into the isthmus as a control, no such delay was observed.The advantage of uterine over tubal insemination was attributed to a synergistic effect of the uterus and Fallopian tubes on those spermatozoa that penetrated the eggs. The nature of the membrane‐related changes in the spermatozoon initiated during passage through the uterus and utero‐tubal junction that facilitate rapid capacitation remains unknown, but is thought to involve modification or removal of seminal plasma constituents from the sperm surface. It was inferred that seminal plasma does not enter the Fallopian tubes of oestrous pigs in significant amounts after mating.
Comparative studies of hemoglobins from the clouded tiger salamander before and after metamorphosis
Authors: Woody A‐Young , Justus J. T. 
Published: June 2005

AbstractSome comparative biochemical studies on the hemoglobin from the clouded tiger salamander, Ambystoma tigrinum nebulosum, before and after metamorphosis indicate (1) there is no hemoglobin change with metamorphosis; (2) both hemoglobins show three major fractions (Fractions I, II, III) in ion exchange chromatography and two bands in gel electrophoresis; (3) these fractions possess identical chemical properties except for their electrophoretic mobilities, and peptide maps; (4) Under our experimental conditions, Fraction II can be formed by the appropriate recombination of subunits present in equilibrium with Fractions I and II.
Biosynthesis of lipovitellin by the crustacean ovary
Authors: Lui Chung W. , Sage Becky A. , O'Connor John D. 
Published: June 2005

AbstractThe in vitro incorporation of 3H‐amino acids into purified lipovitellin by cultured crustacean ovaries can be demonstrated using either density gradient centrifugation or preparative electrophoresis as a final purification step. In addition 3H‐glycerol is incorporated into the phosphatidyl choline moiety of the lipovitellin. This evidence strongly suggests that the ovary is capable of synthesizing both the lipid and the protein components of the lipovitellin and therefore may not incorporate such moieties intact from the circulating hemolymph.
Metabolism of ovomucoid by the developing chick embryo
Authors: Oegema Theodore R. , Jourdian George W. 
Published: June 2005

AbstractA glycoprotein resembling ovomucoid was purified from chorioallantoic membranes of 12.5 day chick embryos by a sequential procedure involving zinc chloride precipitation, hydroxylapatite chromatography, and ion exchange chromatography on DEAE‐ and CM‐cellulose. The resulting preparation was homogeneous as indicated by polyacrylamide gel electrophoresis at 3 pH values, isoelectric focusing, ultracentrifugation, and immunochemical analysis. The purified material had an isoelectric point of 4.8, molecular weight of 29,500 and contained 1.6 moles of galactose, 7.7 moles of mannose, 22.8 moles of N‐acetylglucosamine and 0.4 mole of glucose per mole of protein. The ovomucoid fraction inhibited bovine trypsin, forming a 1 to 1 complex on a molar basis, and elicited a positive anaphylactoid response in albino rats at levels as low as 0.5 μg. A specific ovomucoid antiserum was obtained from rabbits that allowed investigation of the mobilization and metabolism of ovomucoid in the developing chick embryo. These studies revealed that between days 12 and 13 of embryo development a progressive migration of ovomucoid occurs from the albumin sac to the amnionic sac. The glycoprotein is then swallowed and transported through the gut to the yolk sac, where it is catabolized by proteases and glycosidases contained in the yolk sac membrane. Between day 12 of embryo development and day 7 after hatching, ovomucoid appeared in the serum of the chick and reached a maximum value of 2.4 mg % on day 18 of embryo development.
Effect of actinomycin D on protein synthesis by delayed implanting mouse embryos in vitro
Authors: Weitlauf Harry M. 
Published: June 2005

AbstractBlastocysts were collected from the uteri of intact or ovariectomized mice and incubated with or without actinomycin D in a medium containing [14C] amino acids. In the absence of actinomycin D the rate of amino acid incorporation by blastocysts from intact mice (i.e., normal embryos) was constant; the rate of amino acid incorporation by blastocysts from ovariectomized mice (i.e., delayed implanting embryos) was initially low and increased to the normal value after four hours in vitro. In the presence of actinomycin D the rate of amino acid incorporation by normal embryos was only slightly reduced but the expected increase in the rate of amino acid incorporation by delayed implanting embryos was completely blocked. It is suggested that metabolic “activation” of delayed implanting mouse embryos requires the synthesis of new RNA.
Transport, capacitation and fertilizing ability of epididymal spermatozoa
Authors: Overstreet J. W. , Bedford J. M. 
Published: June 2005

AbstractEqual numbers of rabbit spermatozoa from the proximal cauda epididymidis and ejaculate of the same male were mixed and inseminated intravaginally. Their competitive performance in the same female was evaluated by identification of the two populations with x‐irradiation marking (fertilizing spermatozoon) and fluorescein isothiocyanate labelling (spermatozoa in the uterus and egg vestments). Following such mixed inseminations, epididymal spermatozoa from thirteen males fertilized 48% of 251 eggs recovered 50 hours after HCG injection and comprised 55%, 59% and 73% of spermatozoa in the perivitelline space, zona pellucida and mucin layer. When mixed spermatozoa from eight other males were inseminated 5 hours after HCG and the eggs were recovered 8 hours later (13 hours after HCG), epididymal spermatozoa accounted for 53% of the perivitelline and zona spermatozoa in 108 eggs and more than 50% of the uterine spermatozoa in seven of fifteen females. Cleavage of eggs fertilized by spermatozoa from the distal corpus epididymidis and ejaculate of the same male (eight males) was compared by insemination of the respective sperm populations into contralateral oviducts of the same female (sixteen females). There was no significant difference in the level of fertilization or the stage of cleavage 27 hours after insemination and HCG, whether eggs were fertilized by epididymal or ejaculated spermatozoa. These results indicate that once epididymal spermatozoa have acquired the capacity to penetrate the egg, they do not differ from ejaculated spermatozoa in their transport, capacitation, fertilizing ability or competence to sustain development of the egg to the sixteen cell stage.
Meiotic maturation of the mammalian oocyte in vitro: Effect of dibutyryl cyclic AMP on protein synthesis
Authors: Stern Samuel , Wassarman Paul M. 
Published: June 2005

AbstractMouse oocytes arrested in dictyate of the first meiotic prophase by dibutyryl cyclic AMP accumulated exogenous valine at the same rate as oocytes undergoing meiotic maturation. The apparent rate of protein synthesis and the spectrum of proteins synthesized were not significantly affected by the presence of dibutyryl cyclic AMP in the culture system. These results suggest that cytoplasmic maturation of the mammalian oocyte proceeds independently of nuclear progression during the period required for completion of the first meiotic division in vitro.
Observations on the effect of human chorionic gonadotrophin on the antler cycle of fallow deer
Authors: Jaczewski Zbigniew , Michalakowa Wieslawa 
Published: June 2005

AbstractThree experiments on the administration of HCG to fallow deer bucks are described and analysed together with another experiment described earlier. In two cases the administration of HCG was begun before antler shedding and resulted in retardation of their loss and in an inhibition of new growth. The next antlers were of a smaller size. These effects can be attributed to the influences of HCG on testosterone secretion by the testes.In two other experiments the administration of HCG was begun on the day the antlers were shed. In one case antler growth was stopped completely and no anti‐HCG antibodies were detected in blood. In the second case the antlers grew in spite of HCG injections and a high titre of antibodies was detected in the blood. The anti‐HCG antibodies were only detected in the buck which received HCG injections a second time after a four‐year interval.
Intracellular actions of 5‐hydroxytryptamine on the bivalve myocardium. I. Adenylate and guanylate cyclases
Authors: Higgins William J. 
Published: June 2005

AbstractThe effects of the neurotransmitters 5‐hydroxytryptamine (5HT) and acetylcholine (ACh) on the adenylate and guanylate cyclase activities in the ventricles of two species of bivalve molluscs, Mercenaria mercenaria and Macrocallista nimbosa, were examined. 5HT increased molluscan adenylate cyclase activity and intracellular cyclic AMP; ACh had no effect. Neither of these agents significantly altered ventricular cyclic GMP. A positive correlation between the excitatory action of 5HT and the simultaneous increase in intracellular cyclic AMP strongly suggests that this nucleotide mediates 5HT excitation. This proposal is further supported by experiments on ventricles of Modiolus demissus granosissimus that are depressed by 5HT and exhibit very low levels of adenyl cyclase activity. However, classical pharmacological evidence is lacking; cyclic AMP, dibutyryl cyclic AMP, and phosphodiesterase inhibitors have no effect on the mechanical activity of isolated bivalve ventricles.
Effects of prolactin and growth hormone on protein synthesis in larval and adult frogs (Rana pipiens)
Authors: Snyder Benjamin W. , Frye B. E. 
Published: June 2005

AbstractFrogs and tadpoles (Rana pipiens) were treated with mammalian prolactin or growth hormone for several days, then injected with 14C‐leucine. Fourteen to sixteen hours later the animals were killed and the amount of label incorporated into protein of muscle, liver, and gut was measured.Growth hormone stimulated the incorporation of leucine into protein of gastroenemius muscle and small intestine, but not liver, of the frog. Prolactin had no effect on amino acid incorporation in any of these tissues in the frog. Prolactin stimulated the incorporation of leucine into protein of tail muscle, intestine and liver of tadpoles. The effect was not entirely consistent, and was of a smaller magnitude than was expected on the basis of the growth‐promoting effects of prolactin in tadpoles. This problem is discussed. Growth hormone had no effect on protein synthesis in any of these tissues in any experiment.
Selective X‐irradiation of the cartilage at the regenerating margin of rabbit ear holes
Authors: Grimes L. Nichols 
Published: June 2005

AbstractX‐rays in doses of 3000r inhibit the regeneration which normally occurs from the margins of full thickness rabbit ear holes. Irradiated ears containing unirradiated cartilaginous sheets regenerate new tissue, including cartilage, nearly as well as controls. Selective irradiation of the cartilaginous layer in an otherwise unirradiated ear also permits in‐growth, but no chondrogenes is occurs.
The localization and fate of concanavalin a in amoebae of the cellular slime mold, Dictyostelium discoideum
Authors: Gillette Martha Ulbrick , Dengler R. E. , Filosa M. F. 
Published: June 2005

AbstractTwo different methods for the localization of Con A indicate that this lectin is bound to the surface of Dictyostelium discoideum amoebae. Redistribution of the Con A receptors occurs both on cells in suspension and cells moving on an agar surface. Internalization of the Con A does not occur.
The ultrastructure of regeneration in the severed newt optic nerve
Authors: Turner James E. , Singer Marcus 
Published: June 2005

AbstractRegrowing nerve fibers are seen in the regenerating newt (Triturus viridescens) optic nerve as early as the fourth postoperative day (4 p.o.d.). The first fibers are found growing through gutters, troughs or tunnels formed by glial cell processes which may serve as pathways to direct the fibers. By 6 p.o.d. regenerating nerve fibers exist in scattered “clusters” growing about the path established by the first fibers. By 10 p.o.d. the clustered appearance is replaced by a more uniform distribution throughout the regenerating nerve.Beginning with 6 p.o.d. there are increasing signs of spontaneous loss of some regenerating axons. By 21 p.o.d. the loss reaches a peak. The loss appears to be accompanied by continued ingrowth of new fibers. Even as late as 117 p.o.d. the optic nerve population is still not stable for there are signs both of continued nerve growth as well as spontaneous axon loss. Glial myelination of regenerated fibers sets in about 117 p.o.d. and proceeds from the initial lesion centrally toward the optic tectum. There appears to be a direct relation between axon diameter and the initiation of myelination.
The hypoglycemic effects of external insulin on fish and frogs
Authors: Munford John , Greenwald Lewis 
Published: June 2005

AbstractPrevious reports of “insulin shock” induced in fish (and frogs) by externally applied insulin have been confirmed. The insulin induced coma can be reversed by either external glucose, sucrose, or epinephrine. Experiments on rainbow trout have shown that the externally applied insulin acts as though it enters the fish in that a typical hypoglycemia is caused. The action of insulin is via the gills and does not require participation of the digestive tract.
Sex reversal in Betta splendens Regan with emphasis on the problem of sex determination
Authors: Lowe Thomas Philip , Larkin Jeanne R. 
Published: June 2005

AbstractTo gain insight into the sex‐determining mechanism of the Siamese fighting fish, Betta splendens, sex‐reversed individuals were bred and the ratios of the spawnings were examined. Sex‐reversal of 245 females was undertaken by ovariectomizing them; of these, 104 became sex‐reversed. Twenty‐three of these latter fish were mated to normal females and eleven spawnings were raised to maturity.These spawnings resulted in all female broods or mixed broods. Were the male fish heterogametic, a view currently held by some authors, no males would be produced in these spawnings. Thus, male heterogamety was not substantiated in this study.Contrary to other studies, the experimental sex reversal of females is not a rare event since nearly two‐thirds of the fish that survived the surgery became sex‐reversed.Gross dissection and histological observation of sex‐reversed fish revealed a regenerated, unpaired duct which remained after the ovaries had been removed. The tissue of the regenerate was testicular and contained active spermatogenesis.Some alternative methods of sex determination which may apply to the Betta are examined. These include the possibility of two different sex‐determining races, the effects of exogenous factors, and a polygenic system of sex determination.
Avian scale development. V. Ultrastructure of the chorionic epithelium induced by anterior shank dermis from the scaleless mutant
Authors: Sawyer R. H. 
Published: June 2005

AbstractIn combination with dermis from the anterior shank skin of the scaleless mutant, the chorionic epithelium forms an epidermis whose ultrastructural features are indistinguishable from those seen along the inner surface of normal scales and along the anterior shank of the scaleless mutant.
Xenoplastic combinations between chick chorionic epithelium and fetal monkey dermis
Authors: Sawyer R. H. 
Published: June 2005

AbstractFetal monkey dermis from the sole of the foot or ear induces the chick chorionic epithelium (CE) to form an epidermis that histologically resembles chick rather than monkey. These results support the conclusion that in epithelial‐mesenchymal interactions between animals of different vertebrate classes the epithelium responds in a species‐specific manner. Differences were noted, however, in the response of the avian CE to either the sole or ear dermis.
Orientation of homing pigeons: Direct sight of sun not necessary
Authors: McDonald Dennis L. 
Published: June 2005

AbstractHoming pigeons do not need to see the sun directly in order to orient in a Kramer‐type cage. Five homing pigeons were directionally trained in the traditional manner with a clear view of the sky and sun overhead. They were then tested while wearing a sun shade which prevented them from seeing any of the sky out of the top of the cage. All of the birds were able to maintain their orientation. Shadows on the floor of the apparatus may have provided cues. These results suggest a mechanism pigeons may use to obtain information from the sun, that is, by looking at shadows on the ground. Experiments of a similar nature with free‐flying birds are needed.
Gas transport and blood acid‐base balance in diving sea snakes
Authors: Seymour R. S. , Webster M. E. D. 
Published: June 2005

AbstractThe values of hemoglobin concentration, Hb‐O2 affinity and buffering capacity of the blood of six sea snake species considerably overlap values from terrestrial squamates. Decreased blood pH had little effect on the P50 but increased the n‐value of Hb‐O2 equilibrium curves.The O2 saturation of blood in the dorsal aorta varied between about 30 and 70% during voluntary diving in Acalyptophis peronii and Lapemis hardwickii. Voluntary dives ended when the lung Po2 was about mm Hg and the arterial Po2 about 30 mm Hg indicating that roughly half of the O2 reserves had been used. In conjunction with relatively stable blood lactate concentration and pH, this indicates that voluntary dives occurred largely aerobically. In contrast, forced dives resulted in depletion of O2 reserves and large changes in blood acidbase balance. Long recovery periods following forced dives are inconsistent with field observations and thus suggest that extensive anaerobic metabolism does not normally occur in sea snakes. Bradycardia was not evident during forced dives.Large differences in Po2 between the lung and dorsal aorta indicated considerable right to left shunting either in the heart or in the lung. Venous blood represented over 50% of the systemic flow when there was considerable O2 in the lung. Therefore blood Po2 may remain relatively low despite elevated lung Po2 resulting from diving. In view of substantial capability for extra‐pulmonary gas exchange, high shunting reduces the possibility of losing O2 through the skin and also may help prevent decompression sickness following deep dives.
Development of parthenogenetic membranes in double‐yolked and injected chicken eggs
Authors: Sarvella Patricia , Gehman Melvin 
Published: June 2005

AbstractDevelopment of parthenogenetic eggs is expressed in a Dark Cornish stock by either membrane or embryo formation. Double‐yolked eggs have membranes developing in zero, one, or two yolks. The incidence of double‐yolked eggs with two membranes was higher than expected when compared with the incidence of single‐yolked eggs from the same hens. Membrane formation was increased over that of the controls by injecting saline, Ringer's solution, or ground crude membranes. Yolk and membranes filtered through a 3 μ filter or autoclaved did not increase membrane formation over that of the controls. Fertile membranes behaved like parthenogenetic membranes.
Alkaline phosphatase isozymes of Xenopus laevis embryos and tissues
Authors: Maekawa H. , Yamana K. 
Published: June 2005

AbstractAlkaline phosphatase was obtained by treating embryos of Xenopus laevis with n‐butanol at different developmental stages from gastrula to tadpole; the enzyme was also obtained from adult kidney, liver, and intestinal mucosa. Purification was carried out by gel filtration and polyacrylamide gel electrophoresis.The enzyme activity is chromatographically spearated into two peaks, with molecular weights of approximately 200,000 and 400,000. Alternatively, two groups may be characterized on the basis of their electrophoretic mobilities, which correspond to the different molecular weight classes.Effects of pH, temperature, inhibitors, and substrate concentration were studied. The kinetic and physical properties of the two alkaline phosphatase isozymes are similar, and are comparable to the properties reported for this enzyme from other vertebrates. Alkaline phosphatase activity increased sharply at the gastrula stage and reached a plateau at the late tailbud stage. During this period there was an 18‐fold increase in activity.
Fertilizing ability of mouse sperm from different epididymal regions and after washing and centrifugation
Authors: Hoppe P. C. 
Published: June 2005

AbstractThe ability of caput, corpus, and cauda epididymal and vasa deferentia mouse sperm to fertilize eggs in vitro was investigated. Cauda epididymal sperm fertilized 45 of 54 ova, whereas caput and corpus sperm fertilized a negligible number of ova, thus indicating their immaturity. Vasa deferentia sperm fertilized only 10 of 52 ova and their reduced fertility may be due to aging in vivo. No difference in preimplantation development of the resulting zygotes with respect to the sperm source was observed.Three centrifugations and resuspensions of cauda epididymal sperm in fresh medium did not affect their fertilizing ability. I conclude that fertilization in vitro can occur after removal of epididymal secretions.
Feulgen microspectrophotometric analysis of deoxyribo‐nucleoprotein organization in larval and adult freshwater sponge nuclei
Authors: Harrison Frederick W. , Cowden Ronald R. 
Published: June 2005

AbstractMicrospectrophotometric measurements of nuclei of adult choanocytes and archeocytes and larval archeocytes and flagellated ectodermal epithelia from stages III and IV were undertaken on tissues from the freshwater sponge, Eunapius fragilis (Leidy). The condensed nuclei of differentiated choanocytes and stage IV flagellated epithelial cells presented integrated extinction values about 64% of those obtained for either adult or larval archeocytes. This suggests that such measurements represent sensitive indicators of deoxyribo‐nucleoprotein‐complex organization; thus, nuclear differentiation. Further, no large population of G2 (4C) nuclei was found among these populations as has been reported in two classes of coelenterates.