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B T Storey

Publications and source records attributed to B T Storey.

At least 91 records · Page 5Linked to original sources
PubMed1979

Mouse gamete interactions during fertilization in vitro. Chlortetracycline as a fluorescent probe for the mouse sperm acrosome reaction.

We have developed an assay for detecting the acrosome reaction in mouse sperm using chlortetracycline (CTC) as a fluorescent probe. Sperm known to be intact with nonreacted acrosomes show CTC fluorescence in the presence of Ca2+ over the anterior portion of the sperm head on the plasma membrane covering the acrosome. Sperm which have undergone the acrosome reaction do not show fluorescence on the sperm head. Mouse sperm bind to zonae pellucidae of cumulus-free eggs in vitro in a Ca2+-dependent reaction; these sperm are intact by the CTC assay. Intact sperm bind to mechanically isolated zonae under the same conditions: the egg is apparently unnecessary for this inital reaction. Sperm suspensions, in which greater than 50% of the motile population had completed the acrosome reaction, were prepared by incubation in hyperosmolal medium followed by treatment with the divalent cation ionophore, A23187. Cumulus-free eggs challenged with such sperm suspensions preferentially bind intact sperm; acrosome-reacted sperm do not bind. We conclude that the plasma membrane of the mouse sperm is responsible for recognition of the egg's zona pellucida and that the obligatory sequence of reactions leading to fusion of mouse gametes is binding of the intact sperm to the zona pellucida, followed by the acrosome reaction at the zona surface, followed in turn by sperm penetration of the zona.

Acrosome↗
PubMed1977

Turbidimetric analysis of human sperm motility.

A turbidimetric method has been developed for determining rapidly the fraction of sperm in human ejaculates which show the most vigorous motility. The method is based on the fact that sperm cells so endowed will be the first to swim upward into clear medium from a concentrated cell suspension at the bottom of an optical cuvette. This results in a time-dependent increase in turbidity in the medium which is recorded spectrophotometrically as an increase in absorbance. The determination requires 10 minutes and yields both the fraction of rapidly moving sperm, FRM, and their average velocity, VRM. Examination of 25 samples yielded FRM values of 10% or lower, whereas values for VRM averaged about 100 microns/second. These vigorously motile cells may be the best candidates for fertilization, and samples with a high fraction of such cells should have high fertilizing capacity. It is suggested that this simple turbidimetric test be used in evaluation of human semen as a possible indicator of fertilizing capacity.

Humans↗
PubMed1977

Hydrogen ion and carbon dioxide content of the oviductal fluid of the rhesus monkey (Macaca mulatta).

The pH in the oviduct lumen of adult female rhesus monkey (Macaca mulatta) during the menstrual cycle was measured by means of miniaturized pH electrodes. Two types were used: one was a flexible electrode 1.4 mm in diameter; the other was a rigid electrode 0.8 mm in diameter. The same results were obtained with both types. For PCO2 measurements, the pH electrodes was converted to a Severinghaus tyep electrode covered with a Teflon membrane. During the follicular phase, the pH remains constant in the range 7.1 to 7.3. In association with ovulation, there is a sudden increase in the pH to the range 7.5 to 7.8. The pH remains high through the luteal phase. The PCO2 values obtained showed no evident changes with day of cycle. The range of values estimated was wide because of drift in electrode calibration, with the average level about 89 Torr, compared with 40 Torr for blood. At the average pH of 7.2 in the follicular phase, this value of PCO2 corresponds to 35 mM HCO3-; at the average pH of 7.6 of the secretory phase, this value corresponds to 90 mM HCO3-. This increase in pH and HCO3- after ovulation would be expected to enhance dispersal of corona cells during fertilization and to provide a favorable environment for the developing embryo.

Animals↗
PubMed1976

Light scattering from suspensions of membrane fragments derived from sonication of beef heart mitochondria.

The intensity of light scattering from suspensions of membrane fragments prepared by sonication of beef heart mitochondria in the presence of EDTA at alkaline pH (ESMP) was determined at 45, 90, and 135 degrees with light of wavelength 546 nm. The dissymmetry ratio Z = I45 degrees c/I135 degrees c, where I45 degrees c and I135 degrees c are the scattering intensities at 45 and 135 degrees extrapolated to zero particle concentration and corrected for reflectance effects, was used to calculate particle size from the Rayleigh-Gans-Debye theory. An average particle diameter D of 184-190 nm was obtained, within the range of particle diameter 50-300 nm determined previously by electron microscopy. This average diameter determined by light scattering is a useful parameter for characterization of ESMP particle size. We propose the term: light scattering average particle diameter, DLS, for this parameter. The refractive index of ESMP was determined to be 1.443 by measurement of scattering intensity in buffer solutions of varying sucrose concentration. The value of Z was independent of sucrose concentration in this determination, showing that the particles are osmotically inactive toward sucrose. The values of average particle diameter DLS and of refractive index fall within the range of validity of the Rayleigh-Gans-Debye theory, for which light scattering changes are attributable solely to dimension change, rather than to change in particle refractive index. Uptake of water accompanying energy-linked salt uptake in ESMP was calculated from light scattering changes to be 0.18 mul of H2O/mg of protein, compared with 0.49 mul of H2O/mg of protein measured by dextran inaccessibility. Measurement of light scattering changes provides a rapid and sensitive method for determining volume changes of ESMP. The magnitude of the volume change observed during energy-linked water and salt uptake and the initial degree of hydration suggests that ESMP are analogous to polyelectrolyte gels with regard to sorption of strong electrolytes and that the Donnan formulation for ion exchange equilibria may be usefully applied to these processes in ESMP.

Animals↗
PubMed1976

Oxygen tension in the oviduct of the rhesus monkey (Macaca mulatta).

The oxygen tension in the oviductal fluid of adult female rhesus monkeys was measured by means of miniaturized, flexible, oxygen probes between days 5 and 22 of the menstrual cycle. In the follicular phase, the value was very low, less than 10 Torr. At the time of ovulation to about 5 to 7 days thereafter, the oxygen tension in the tube on the side of ovulation increased within approximately 2 minutes after insertion of the oxygen probe from the low level to the same value as in the blood. In the contralateral oviduct, the oxygen tension remained at less than 10 Torr. These findings suggest that, in the absence of ovulation, the blood-oxygen supply of the oviduct provides the exact oxygen requirement of oviductal tissue, with no excess oxygen available for the tubal fluid. At and shortly after ovulation, the presence of a probe stimulates, by an unknown mechanism, an increase in the oxygen tension in the oviductal fluid which provides an environment sufficiently well-oxygenated for gamete survival, fertilization, and subsequent further development of the embryo. We suggest that the ovum entering the oviduct provides a similar stimulus with a similar result by the same unknown mechanism.

Animals↗
PubMed1976

Respiratory Chain of Plant Mitochondria: XVIII. Point of Interaction of the Alternate Oxidase with the Respiratory Chain.

Oxidation of the respiratory chain carriers of anaerobic, CO-saturated skunk cabbage (Symplocarpus foetidus) mitochondria, by means of an O(2) pulse, proceeds primarily through the cyanide-insensitive alternate oxidase, since the oxidation of cytochromes a and a(3) takes place with a half-time of 3 seconds, corresponding to the rate of dissociation of CO from reduced cytochrome a(3). Ubiquinone and part of the flavoprotein are oxidized within 1 second under these conditions, and this rapid rate of oxidation is strongly inhibited by m-chlorobenzhydroxamic acid (mCLAM), a specific inhibitor of the alternate oxidase of plant mitochondria. The rate of ubiquinone oxidation under these conditions in white potato (Solanum tuberosum) mitochondria, which have no alternate oxidase, is the same as that in skunk cabbage mitochondria treated with mCLAM. Ubiquinone, thus identified as the carrier common to both the cytochrome and alternate oxidase pathways, is linked to the alternate oxidase by a flavoprotein of midpoint potential 50 millivolts more negative with which it is in equilibrium. This arrangement provides a switch for diverting electron transport primarily through the cytochrome pathway under state 3 conditions and primarily through the alternate oxidase pathway under state 4 conditions.

Journal Article↗
PubMed1976

Midpoint potentials of the mitochondrial cytochromes of Crithidia fasciculata.

The midpoint potentials of the mitochondrial respiratory chain cytochromes of the protozoan Crithidia fasciculata at pH 7.2, Em7.2, show great similarity to those measured in higher organisms. Values of Em7.2 for cytochromes a and a3 are +165 and +340 mV. Both c cytochromes have Em7.2 = +230 mV. There are two b cytochromes with the same spectral characteristics with Em7.2 = -20 and -135 mV. These values are compatible with two sites of energy conservation for oxidative phosphorylation in these mitochondria. All cytochrome components show potentiometric titrations with n = 1. There is a fluorescent flavoprotein in these mitochondria with Em7.2 = -40 mV and n =2, whose function is not known.

Animals↗
PubMed1976

Factors in diminution of uteroglobin secretion in the rabbit.

Uteroglobin was measured under various hormonal conditions: pregnancy, pseudopregnancy, pseudopregnancy with exogenous progesterone, pseudopregnancy with exogenous 20alpha-hydroxyprogesterone, ovariectomy with exogenous progesterone, ovariectomy with exogenous estrogen, ovariectomy with exogenous estrogen and progesterone, and ovariectomy with either exogenous progesterone or estrogen and progesterone, plus uterine trauma. In pregnant females, uteroglobin levels diminished sharply after day 9. In pseudopregnancy, high concentrations were maintained through day 14. Although exogenous progesterone did not prevent this decrease in pseudopregnant females, re-elevation occurred in the continued presence of progesterone. A similar pattern of decline and re-elevation was found in ovariectomized females that received injections of estrogen and progesterone. With an increase in estrogen dosage, the period of uteroglobin secretion was shorter and the magnitude lower. Ovariectomized females receiving only progesterone did not manifest a clear uteroglobin diminution. Uterine trauma on day 7 of exogenous steroid administration to ovariectomized females was followed by a diminution in uteroglobin. At the dosage level used, administration of 20alpha-hydroxyprogesterone did not affect the peak uteroglobin secretion occurring on day 5 of pseudopregnancy. Ovariectomized females receiving estrogen or sesame oil vehicle had barely detectable levels of uteroglobin. A uteroglobin-estrogen complex is suggested as a possible inhibitor of uteroglobin synthesis by a feedback inhibition pathway in pseudopregnant females and in ovariectomized females treated with progesterone plus estrogen. In pregnant females, a uteroglobin-estrogen complex and/or the uterine decidual response to implantation could control uteroglobin synthesis.

20-alpha-Dihydroprogesterone↗
PubMed1975

Energy metabolism of spermatozoa. V. The Embden-Myerhof pathway of glycolysis: activities of pathway enzymes in hypotonically treated rabbit epididymal spermatozoa.

Seven enzymes of the Embden-Myerhof pathway of glycolysis were assayed in hypotonically treated epididymal sperm from mature rabbits. These were: fructose-biphosphate aldolase, triosephosphate isomerase, glyceraldehydephosphate dehydrogenase, 3-phosphoglyceromutase, enolase, pyruvate kinase, and lactate dehydrogenase. These enzymes were firmly enough bound to the cell structure to resist removal by washing after hypotonic treatment and had maximal activities comparable to, or greater than, the rate of mitochondrial pyruvate oxidation, so that rapid oxygen uptake was observed with intermediates of the glycolytic pathway. The activity of lactate dehydrogenase in a typical preparation of hypotonically treated cells was 5.3 mumoles/minute x 10(9) cells at 25 degrees C for pyruvate reduction in the hypotonically treated cells and 4.8 mumoles/minute x 10(9) cells in the thrice-washed hypotonically treated cells. The Km for pyruvate was 1.4 mM while that for lactate was 4.4 mM. By contrast, the maximal activity of pyruvate oxidation by mitochondria was 0.10 microgram atom of oxygen/minute x 10(9) cells, corresponding to 0.020 mumole of pyruvate/minute x 10(9) cells, and the Km for pyruvate was 5 microM. These enzyme parameters favor high lactate production from glucose in aerobic glycolysis.

Animals↗
PubMed1974

The Respiratory Chain of Plant Mitochondria: XVI. Interaction of Cytochrome b(562) with the Respiratory Chain of Coupled and Uncoupled Mung Bean Mitochondria: Evidence for Its Exclusion from the Main Sequence of the Chain.

Cytochromes b(553), b(557), and b(562) of mung bean (Phaseolus aureus) mitochondria become partially reduced with endogenous substrate on addition of antimycin A to the aerobic mitochondrial suspension. Addition of ATP causes partial reoxidation of the three cytochromes. This partial oxidation by ATP is inhibited by oligomycin and reversed by uncoupler. Ubiquinone does not appear to act as electron acceptor for the oxidation reaction, but a nonfluorescent flavoprotein, or possibly ironsulfur protein, component does appear to act as acceptor. This is consistent with reverse electron transport driven by ATP across the first site of energy conservation of the respiratory chain. Endogenous pyridine nucleotide and the fluorescent flavoprotein with E(m7.2) = -155mv (midpoint potential at pH 7.2, referred to normal hydrogen electrode) in uncoupled mitochondria become reduced in anaerobiosis attained by oxidation of succinate in the absence of respiratory inhibitors of the cytochrome chain, provided that Pi and ATP are present. Under these same conditions, cytochrome b(557) is completely reduced but cytochrome b(562) remains nearly completely oxidized. There is no equilibration across the first site of energy conservation between the carriers on the low potential side and cytochrome b(562) with E(m7.2) = -77mv on the high potential side. It is concluded that cytochrome b(562) is not a part of the main sequence of electron transport carriers of the mitochondrial respiratory chain of plants; it can participate in redox reactions with the respiratory chain in coupled mitochondria but not in uncoupled mitochondria unless antimycin A is present.

Journal Article↗