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J L Bailey

Publications and source records attributed to J L Bailey.

At least 55 records · Page 3Linked to original sources
PubMed1995

Regulation of internal Ca2+ by chilled bull and boar spermatozoa.

Intracellular Ca2+ in ejaculated spermatozoa from five bulls and five boars was determined with indo-1,AM in Ca(2+)-free medium. Aliquots of each ejaculate were then wrapped and held either on ice or at 25 degrees C for 20 min. At this time all samples were returned to 25 degrees C, either Ca(2+)-free medium or medium containing 1 mM Ca2+ was added, and intracellular Ca2+ was determined for an additional 120 min. Before and immediately after chilling, internal Ca2+ in bull spermatozoa did not differ. However, exogenous Ca2+ caused both control and chilled bovine spermatozoa to accumulate Ca2+ over the subsequent 120 min (P < 0.01) with the control spermatozoal rate of Ca2+ intake being faster than that of the chilled (slopes, 29.531 vs 8.374 relative Ca2+ units/min; least squares means (lsmean) x 10(4) +/- 1.901 (pooled SE); P < 0.01). Viability of all spermatozoa was reduced after Ca2+ exposure, and the acrosomal morphology of chilled cells was adversely affected by Ca2+. For boar spermatozoa, chilling caused an immediate increase in internal Ca2+, confirming the greater sensitivity of boar spermatozoa to low temperatures. The presence of exogenous Ca2+ caused greater Ca2+ uptake by both control and chilled porcine cells relative to their Ca(2+)-free analogues (0.939 vs 0.764 and 1.015 vs 0.836 Ca2+ units; lsmean +/- 0.166 (pooled SE); P < 0.01 for control and chilled boar spermatozoa with and without Ca2+ at 150 min). Control spermatozoa, however, accumulated Ca2+ (P < 0.01) at a much greater rate (slope, 20.964 +/- 2.73 relative Ca2+ units x 10(4)/min; P < or = 0.001) than chilled cells, which only tended (P = 0.08) to accumulate Ca2+ (slope, 4.782 +/- 2.73 relative Ca2+ units x 10(4)/min). This study suggest that chilling causes a species-specific effect on Ca2+ regulatory capabilities of spermatozoa that differs from cold shock and that spermatozoa may be able to compensate, at least partially, for such injuries.

Animals↗
PubMed1995

Sperm from mice carrying one or two t haplotypes are deficient in investment and oocyte penetration.

The t haplotypes, mutant forms of the proximal third of mouse chromosome 17 (the t complex), contain factors that contribute to defective sperm function in fertilization. Males carrying two t haplotypes (tx/ty mice) are sterile; their sperm have very poor motility and are unable to penetrate zona-free eggs. Although males carrying one t haplotype (t/+) are fertile, genetic evidence suggests that the sperm carrying the normal form of chromosome 17 (+t) are dysfunctional in fertilization, and some or all sperm have abnormal motility. Some of the same genetic factors that cause sterility in tx/ty males probably contribute to the dysfunction of +t sperm from t/+ males; however, it is unclear which steps in gamete interaction are defective in sperm from t/+ males, or whether the defects are similar to those observed in sperm from tx/ty males. We have developed a unique low sperm:egg ratio IVF assay for sperm function in fertilization. Using this assay, we have shown that tw5/+ sperm are less able than congenic +/+ sperm to penetrate the zona (probably due to their abnormal motility) and to penetrate the zona-free oocyte. Since tw5/tw32 sperm are unable to complete these same two steps in sperm-egg interaction, these specific deficits could be involved in both transmission ratio distortion and sterility. We have also shown that tw5/tw32 sperm are deficient in their ability to bind to the zona and to the oolemma. These results suggest that t haplotypes contain loci which affect a number of sperm functions and thus could be a rich source of genes important for sperm-egg interaction.

Acrosome↗
PubMed1995

Experimental acidemia and muscle cell pH in chronic acidosis and renal failure.

To test whether muscle intracellular pH (pHi) decreases when extracellular pH falls, 31P-nuclear magnetic resonance was utilized in rats made acidotic by infusion of HCl, gavage-feeding NH4Cl, or induction of chronic renal failure (CRF). A 2- or 4-h HCl infusion did not lower muscle pHi, even though serum bicarbonate fell to 5 mM. With chronic acidemia, blood pH was 7.15 +/- 0.01 vs. 7.38 +/- 0.02 in pair-fed controls, and muscle pHi was 7.09 +/- 0.01 and 7.14 +/- 0.02, respectively (P < 0.01). pHi in muscle of CRF rats (7.16 +/- 0.01) did not differ from sham-operated, pair-fed controls (7.19 +/- 0.01) despite a blood pH of 7.23 +/- 0.05 in CRF vs. 7.39 +/- 0.01 in controls. Because ion transport is abnormal in CRF, we examined whether recovery of pHi is impaired when muscles of six CRF and control rats were exercised to tetany by stimulation of the sciatic nerve. Neither pHi nor the recovery of pHi differed between CRF and control rats. We conclude that pHi is maintained in muscle in uremia and that signals other than changing pHi must be necessary to disrupt metabolism.

Acidosis↗
PubMed1995

Capacitation of mouse spermatozoa. I. Correlation between the capacitation state and protein tyrosine phosphorylation.

The molecular basis of mammalian sperm capacitation, defined functionally as those processes that confer on the sperm the acquisition of fertilization-competence either in vivo in the female reproductive tract or in vitro, is poorly understood. We demonstrate here that capacitation of caudal epididymal mouse sperm in vitro is accompanied by a time-dependent increase in the protein tyrosine phosphorylation of a subset of proteins of M(r) 40,000-120,000. Incubation of sperm in media devoid of bovine serum albumin, CaCl2 or NaHCO3, components which individually are required for capacitation, prevent the sperm from undergoing capacitation as assessed by the ability of the cells to acquire the pattern B chlortetracycline fluorescence, to undergo the zona pellucida-induced acrosome reaction and, in some cases, to fertilize metaphase II-arrested eggs in vitro. In each of these cases the protein tyrosine phosphorylation of the subset of capacitation-associated proteins does not occur. Protein tyrosine phosphorylation of these particular proteins, as well as sperm capacitation, can be recovered in media devoid of each of these three constituents (bovine serum albumin, CaCl2 or NaHCO3) by adding back the appropriate component in a concentration-dependent manner. The requirement of NaHCO3 for these phosphorylations is not due to an alkalinization of intracellular sperm pH or to an increase in media pH. Caput epididymal sperm, which lack the ability to undergo capacitation in vitro, do not display this capacitation-dependent subset of tyrosine phosphorylated proteins in complete media even after extended incubation periods, and do not fertilize metaphase II-arrested eggs in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Capacitation of mouse spermatozoa. II. Protein tyrosine phosphorylation and capacitation are regulated by a cAMP-dependent pathway.

In the accompanying report (Visconti, P.E., Bailey, J.L., Moore, G.D., Pan, D., Olds-Clarke, P. and Kopf, G.S. (1995) Development, 121, 1129-1137) we demonstrated that the tyrosine phosphorylation of a subset of mouse sperm proteins of M(r) 40,000-120,000 was correlated with the capacitation state of the sperm. The mechanism by which protein tyrosine phosphorylation is regulated in sperm during this process is the subject of this report. Cauda epididymal sperm, when incubated in media devoid of NaHCO3, CaCl2 or bovine serum albumin do not display the capacitation-associated increases in protein tyrosine phosphorylation of this subset of proteins. This NaHCO3, CaCl2 or bovine serum albumin requirement for protein tyrosine phosphorylation can be completely overcome by the addition of biologically active, but not inactive, cAMP analogues. Addition of the active cAMP analogues to sperm incubated in media devoid of NaHCO3, CaCl2 or bovine serum albumin overcomes the inability of these media to support capacitation, as assessed by the ability of the cells to acquire the pattern B chlortetracycline fluorescence, to undergo the zona pellucida-induced acrosome reaction and, in some cases, to fertilize metaphase II-arrested eggs in vitro. The effects of the cAMP analogues to enhance protein tyrosine phosphorylation and to promote capacitation appears to be at the level of the cAMP-dependent protein kinase (PKA), since two specific inhibitors of this enzyme (H-89 and Rp-cAMPS) block the capacitation-dependent increases in protein tyrosine phosphorylation in sperm incubated in media supporting capacitation. Capacitation, as assessed by the aforementioned endpoints, also appears to be inhibited by H-89 in a concentration-dependent manner. These results provide further evidence for the interrelationship between protein tyrosine phosphorylation and the appearance of the capacitated state in mouse sperm. They also demonstrate that both protein tyrosine phosphorylation and capacitation appear to be regulated by cAMP/PKA. Up-regulation of protein tyrosine phosphorylation by cAMP/PKA in sperm is, to our knowledge, the first demonstration of such an interrelationship between tyrosine kinase/phosphatase and PKA signaling pathways.

1-Methyl-3-isobutylxanthine↗
PubMed1994

Calcium influx into mouse spermatozoa activated by solubilized mouse zona pellucida, monitored with the calcium fluorescent indicator, fluo-3. Inhibition of the influx by three inhibitors of the zona pellucida induced acrosome reaction: tyrphostin A48, pertussis toxin, and 3-quinuclidinyl benzilate.

The fluorescent calcium indicator, fluo-3, was loaded as the membrane permeant tetraacetoxymethyl (AM) ester into cauda epididymal mouse sperm at 25 degrees C for 20 min in the absence of bovine serum albumin (BSA) and presence of the dispersant, Pluronic F-127. Excess indicator was removed by two centrifugation washes at 100g for 10 min, a procedure that did not impair sperm motility. Upon resuspension in medium containing 20 mg/ml BSA to promote capacitation, the sperm cells exhibited readily detectable fluorescence uniformly distributed in the cytoplasm. Cell fluorescence was stable over the time of the experiments and was responsive to changes in intracellular calcium concentration, [Ca2+]i. Initial [Ca2+]i was 231 +/- 58 nM (+/- SE, n = 43). Addition of heat-solubilized mouse zonae pellucidae to capacitated sperm increased [Ca2+]i by 106 +/- 19 nM (+/- SE, n = 18), the higher steady-state concentration being reached after 30 min. Subsequent addition of the non-fluorescent calcium ionophore Br-A23187 resulted in a further increase of 114 +/- 18 nM (+/- SE, n = 18), the higher steady-state concentration being reached after 6 min. The increase in [Ca2+]i induced by solubilized zonae pellucidae was largely blocked by 3-quinuclidinyl benzilate (QNB), an antagonist of muscarinic receptors that was earlier shown to block the zona pellucida induced acrosome reaction in mouse sperm (Florman and Storey, 1982: Dev Biol 91:121-130). This [Ca2+]i increase was completely blocked by the tyrosine kinase inhibitor, tyrphostin A48, and by the inactivator of G1 proteins, pertussis toxin. At the concentrations at which they blocked the zona pellucida-induced increase in [Ca2+]i, all three inhibitors also blocked the zona pellucida-induced acrosome reaction. These results indicate that [Ca2+]i increase in is an early, if not the initial, reaction in the sequence leading to zona pellucida induced acrosomal exocytosis in mouse sperm. The observation that the three inhibitors, each having a different mode of action, all block the zona pellucida induced [Ca2+]i suggests that the sperm plasma membrane receptors mediating the zona pellucida induced acrosome reaction may function as a complex, whose formation is activated by zona pellucida ligand binding.

Acrosome↗
PubMed1994

Acidosis and glucocorticoids concomitantly increase ubiquitin and proteasome subunit mRNAs in rat muscle.

In rat muscle metabolic acidosis increases ATP-dependent protein degradation and levels of mRNAs for ubiquitin (Ub) and proteasome subunits. Because adrenalectomy (ADX) abolishes the proteolytic response to acidosis in muscle, we examined whether glucocorticoids (GCs) are necessary for acidosis-induced changes in Ub and proteasome mRNAs in muscles. Total RNA content of the white fiber extensor digitorum longus or mixed fiber gastrocnemius muscles were lowest in muscles of ADX rats given acid plus GCs. In contrast, the abundance of Ub and C2 and C9 proteasome subunits mRNAs were increased in muscles from this group compared with untreated ADX rats or ADX rats given acid or GCs alone. Because total RNA is reduced, the increase in these mRNAs in muscles of ADX rats receiving acid plus GCs provides evidence for a specific activation of the ATP-dependent-Ub-proteasome pathway. Thus, GCs are required but not sufficient to produce the coordinated increase in mRNAs encoding ubiquitin and proteasome subunits occurring in muscles of acidotic rats.

Acidosis↗
PubMed1994

Metabolic acidosis stimulates muscle protein degradation by activating the adenosine triphosphate-dependent pathway involving ubiquitin and proteasomes.

Metabolic acidosis often leads to loss of body protein due mainly to accelerated protein breakdown in muscle. To identify which proteolytic pathway is activated, we measured protein degradation in incubated epitrochlearis muscles from acidotic (NH4Cl-treated) and pair-fed rats under conditions that block different proteolytic systems. Inhibiting lysosomal and calcium-activated proteases did not reduce the acidosis-induced increase in muscle proteolysis. However, when ATP production was also blocked, proteolysis fell to the same low level in muscles of acidotic and control rats. Acidosis, therefore, stimulates selectively an ATP-dependent, nonlysosomal, proteolytic process. We also examined whether the activated pathway involves ubiquitin and proteasomes (multicatalytic proteinases). Acidosis was associated with a 2.5- to 4-fold increase in ubiquitin mRNA in muscle. There was no increase in muscle heat shock protein 70 mRNA or in kidney ubiquitin mRNA, suggesting specificity of the response. Ubiquitin mRNA in muscle returned to control levels within 24 h after cessation of acidosis. mRNA for subunits of the proteasome (C2 and C3) in muscle were also increased 4-fold and 2.5-fold, respectively, with acidosis; mRNA for cathepsin B did not change. These results are consistent with, but do not prove that acidosis stimulates muscle proteolysis by activating the ATP-ubiquitin-proteasome-dependent, proteolytic pathway.

Acidosis↗
PubMed1993

Ca2+ regulation by cryopreserved bull spermatozoa in response to A23187.

The regulation of intracellular Ca2+ by fresh and cryopreserved bull spermatozoa from the same ejaculates (n = 5) was investigated using the fluorescent Ca2+ indicator, indo-1. Relative internal Ca2+ levels of the spermatozoa were monitored for 30 min prior to the addition of phosphate-buffered saline (PBS), 1 mM Ca2+, the Ca2+ ionophore A23187 (0.1 microM), or Ca2+ + A23187; during the additions the levels of intracellular Ca2+ were observed in detail. After these additions, changes in internal Ca2+ levels were monitored for 120 min. The initial intracellular Ca2+ levels in the cryopreserved spermatozoa were greater than those in fresh (1.05 +/- 0.03 vs 0.97 +/- 0.03 Ca2+ units, P = 0.0001). The addition of Ca2+ + A23187 induced elevated cellular Ca2+ in both fresh (P = 0.0177) and cryopreserved spermatozoa (P < or = 0.0588) within 5 s. Ca2+ alone did not differ from Ca2+ + A23187 in increasing Ca2+ in cryopreserved spermatozoa (P = 0.2225); fresh spermatozoa were slower to respond to exogenous Ca2+ alone (P = 0.0438). At the start of the post-treatment 120 min, cryopreserved spermatozoa had more internal Ca2+ than the corresponding fresh samples (P < or = 0.0088) except for those exposed to both Ca2+ + A23187 (P = 0.2918). All spermatozoa increased internal Ca2+ over the post-treatment time except for the cryopreserved PBS controls, and these cryopreserved controls differed from the fresh controls in accumulation of Ca2+ (P = 0.0620). None of the Ca2+/A23187 treatments induced different rates of change in internal Ca2+ over time in fresh cells (P = 0.3142). The rate of Ca2+ accumulation by cryopreserved spermatozoa in the presence of exogenous Ca2+ exceeded controls (23.12 +/- 6.75 vs 8.11 +/- 6.75, P = 0.0005), but A23187, with or without Ca2+, had no effect (P > or = 0.0907). Following Ca2+ measurements, the viability of the cryopreserved samples was reduced (P < or = 0.015) in all but the Ca(2+)-treated spermatozoa (P = 0.1474); no viability differences were noted for fresh spermatozoa (P > or = 0.2298). The cryopreservation process did not affect acrosomal morphology of the indo-1-exposed spermatozoa (P > or = 0.1147). These data indicate that Ca2+ regulation by Ca(2+)- and A23187-challenged bull spermatozoa differs following cryopreservation procedures, possibly relating to the reduced fertilization capacity of commercially cryopreserved semen.

Animals↗
PubMed1990

Effects of cold shock and phospholipase A2 on intact boar spermatozoa and sperm head plasma membranes.

Head plasma membranes (HPM) isolated from cryopreserved boar spermatozoa show an excessive fluidization, which might be involved in the loss of fertility. The current study assessed the ability of cold shock (5 degrees C) and phospholipase A2 (PA2) to duplicate these effects on membrane structure and to affect 45Ca2+ uptake and gross morphological characteristics of whole, fresh boar-sperm. The HPM from cold-shocked sperm showed a significantly greater rate of fluidization over time than did HPM from control sperm. Addition of PA2 (bee or snake venom, 0.1 or 10.0 ng/ml) to HPM from control sperm caused fluidization similar to cold shocking, but to a lesser degree (P less than 0.05). Cold-shocked intact sperm exhibited severe acrosomal disruption, loss of motility, and increased 45Ca2+ uptake relative to control sperm. Addition of PA2 (bee or snake venom, 0.1, 1.0., 10.0, and 1,000 ng/ml) to control sperm had no effect on gross morphology or motility while maintaining or increasing sperm extrusion of 45Ca2+. Therefore, although PA2 can, to some extent, duplicate the effects of cold shock on HPM molecular organization, its lipid hydrolytic action is insufficient to cause all the gross disruptions of severe thermal shock. Both PA2 and cold shock disrupted HPM structure, but only cold shock increased 45Ca2+ uptake, suggesting that cold shock may be increasing 45Ca2+ uptake in areas other than the head. Cold shock disrupts sperm on three levels; membrane molecular organization, intracellular Ca2+ regulation, and gross morphology/motility.

Animals↗
PubMed1989

Effects of semen preservation on boar spermatozoa head membranes.

Head plasma membranes were isolated from the sperm-rich fraction of boar semen and from sperm-rich semen that had been subjected to three commercial preservation processes: Extended for fresh insemination (extended), prepared for freezing but not frozen (cooled), and stored frozen for 3-5 weeks (frozen-thawed). Fluorescence polarization was used to determine fluidity of the membranes of all samples for 160 min at 25 degrees C and also for membranes from the sperm-rich and extended semen during cooling and reheating (25 to 5 to 40 degrees C, 0.4 degrees C/min). Head plasma membranes from extended semen were initially more fluid than from other sources (P less than 0.05). Fluidity of head membranes from all sources decreased at 25 degrees C, but the rate of decrease was significantly lower for membranes from cooled and lower again for membranes from frozen-thawed semen. Cooling to 5 degrees C reduced the rate of fluidity change for plasma membranes from the sperm-rich fraction, while heating over 30 degrees C caused a significantly greater decrease. The presence of Ca++ (10 mM) lowered the fluidity of the head plasma membranes from sperm-rich and extended semen over time at 25 degrees C but did not affect the membranes from the cooled or frozen-thawed semen. The change in head plasma membrane fluidity at 25 degrees C may reflect the dynamic nature of spermatozoa membranes prior to fertilization. Extenders, preservation processes and temperature changes have a strong influence on head plasma membrane fluidity and therefore the molecular organization of this membrane.

Animals↗
PubMed1986

Liquid-chromatographic determination of urinary pentachlorophenol.

We developed and evaluated a simple liquid-chromatographic method for urinary pentachlorophenol (PCIP) determination with ultraviolet detection. PCIP and the internal standard (2,3,5,6-tetrachlorophenol, TCP) were extracted with a solid-phase extraction column, and 50 microL of the collected eluate was injected into the chromatograph. The intra-assay and interassay CVs were 6.6% (n = 20) and 7.9% (n = 10), respectively. The analytical recoveries varied from 89% to 96%, with absolute recoveries ranging from 82% to 88%. Thirty urine specimens collected from 30 unexposed individuals were analyzed by the current method, and results were all less than the minimum detection limit, 0.25 mg/L. Results for five specimens from workers who had been exposed to PCIP ranged from 7.0 to 12.4 mg/L. The standard curve was linear to 300 mg/L. This procedure is adaptable to automated analysis, and therefore suitable for monitoring industrial exposure of workers.

Chlorophenols↗
PubMed1985

Determination of vitamin E in microsamples of serum by liquid chromatography with electrochemical detection.

In this procedure for determination of vitamin E by "high-performance" liquid chromatography with electrochemical detection, 25-microL serum specimens are deproteinized with ethanol. Vitamin E (alpha-tocopherol), its derivatives (beta- and gamma-tocopherols), and the internal standard (delta-tocopherol) are extracted into heptane and the extract is evaporated and the residue reconstituted with methanol before injection into the chromatograph. Within- and between-run CVs for an alpha-tocopherol concentration of 13.6 mg/L were 5.1% (n = 28) and 6.0% (n = 5), respectively. The standard curve is linear to 100 mg/L; the minimum concentration detectable is 0.1 mg/L. Analytical recovery ranged from 99.8% to 104.8%. In 36 specimens collected from apparently healthy subjects who were not taking vitamin supplements, alpha-tocopherol as determined by this method ranged from 4.3 to 9.7 mg/L, from 1.8 to 3.9 mg/L for beta- and gamma-tocopherols. Results by this method (y) and an HPLC-ultraviolet method (x) correlate reasonably (r = 0.81): y = 0.88x - 0.55 mg/L (n = 45). This procedure is adaptable to automated analysis, and the small sample requirement facilitates its applicability to neonates.

Adult↗
PubMed1982

Carbohydrate conservation in the obese: a theory to explain the ease of weight gain.

Changes in the blood concentrations of non-chylomicron triglycerides, insulin, glucose, non-esterified fatty acids (NEFA) and alanine in response to a 4.18-MJ (1,000-kcal) meal were measured in 15 obese and 15 lean volunteers. No differences between the two groups either in quantity or in the pattern of change were detected in the triglycerides, glucose or alanine during the 7-hour period of study. Insulin levels were significantly higher in the obese subjects 1.25 h after the start of the meal, but at no other time. Plasma NEFA were initially depressed in both groups, but thereafter rose to much higher levels in the lean subjects. The results support the hypothesis that the obese conserve more of their ingested carbohydrate as liver glycogen for use between meals, and thereby avoid the high energy cost of fat synthesis.

Adult↗
PubMed1976

Leg ulcers.

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Bandages↗
PubMed1975

Reduced nicotinamide adenine dinucleotide-nitrate reductase of Chlorella vulgaris. Purification, prosthetic groups, and molecular properties.

NADH:nitrate reductase (EC 1.6.6.1) from Chlorella vulgaris has been purified 640-fold with an over-all yield of 26% by a combination of protamine sulfate fractionation, ammonium sulfate fractionation, gel chromatography, density gradient centrifugation, and DEAE-chromatography. The purified enzyme is stable for more than 2 months when stored at minus 20 degrees in phosphate buffer (pH 6.9) containing 40% (v/v) glycerol. After the initial steps of the purification, a constant ratio of NADH:nitrate reductase activity to NADH:cytochrome c reductase and reduced methyl viologen:nitrate reductase activities was observed. One band of protein was detected after polyacrylamide gel electrophoresis of the purified enzyme. This band also gave a positive stain for heme, NADH dehydrogenase, and reduced methyl viologen:nitrate reductase. One band, corresponding to a molecular weight of 100, 000, was detected after sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme contains FAD, heme, and molybdenum in a 1:1:0.8 ratio. One "cyanide binding site" per molybdenum was found. No non-heme-iron or labile sulfide was detected. From a dry weight determination of the purified enzyme, a minimal molecular weight of 152, 000 per molecule of heme or FAD was calculated. An s20, w of 9.7 S for nitrate reductase was found by the use of sucrose density gradient centrifugation and a Stokes radius of 89 A was estimated by gel filtration techniques. From these values, and the assumption that the partial specific volume is 0.725 cc/g, a molecular weight of 356, 000 was estimated for the native enzyme. These data suggest that the native enzyme contains a minimum of 2 molecules each of FAD, heme, and molybdenum and is composed of at least three subunits.

Binding Sites↗