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  • 1
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 39 (1989), S. 327-337 
    ISSN: 0730-2312
    Keywords: phospholipase A2 ; human genes ; pancreatic ; human chromosome mapping ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We described previously the cloning and DNA sequence of the human gene encoding pancreatic phospholipase A2 [DNA 5, 519]. When pancreatic phospholipase A2 (PLA2) cDNA was used to screen a human genomic library, two classes of clones were obtained. One class encoded the pancreatic enzyme, and a second class encoded one exon of an apparently related PLA2. No additional PLA2 gene exons displayed sufficient homology to be detected by the probe. A homologous sequence in both rat and porcine genomic DNA was detected by DNA blot hybridization, and the corresponding gene fragments were cloned and sequenced. Within the deduced amino acid sequences, the presence of known functional residues along with the high degree of interspecies conservation suggests the genes encode a functional PLA2 enzyme form. The encoded sequence lacks Cys11, as do the “type II” viperid venom and other nonpancreatic mammalian PLA2 enzymes. The sequence is distinct from porcine intestinal PLA2 and appears not to be a direct homolog of the recently published rabbit ascites and rat platelet enzymes. Hybridization of DNA probes containing sequences from these genes to genomic DNA blots of mouse/human somatic cell hybrids permitted chromosomal assignment for both. The pancreatic gene mapped to human chromosome 12, and the homologous gene mapped to chromosome 1.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1825-1832 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The wavelength dependence of photodegradation of three “high temperature” aromatic polyamide polymers has been very accurately determined by means of a fast grating spectrograph used in conjunction with a high pressure xenon arc. One of these polymers, the poly-(isophthalamide) of 4,4′-bis(p-aminophenyl)-2,2′bithiazole, was found to be degraded significantly by visible light, especially that of 4140 Å, wavelength. Both the poly-terephthalamide of 1,3-bis(3-aminobenzamide) benzene and Du Pont Nomex, also an aromatic polyamide, were damaged primarily by radiation in the near ultraviolet region. Degradation band maxima for these polymers were observed at 3700 Å, and 3600 Å, respectively. All three thermally resistant polymers were thus found to be degraded by light of much longer wavelength than that which is harmful to other common polymers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 997-1004 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of polymeric steric stabilizers on the dispersion stability of alumina was determined by settling experiments. The theoretical settling density was determined for alumina in a 90:10 wt% toluene-ethanol mixed solvent. Polymers evaluated were sulfonated polystyrenes, Shell's functionalized Kraton block polymers (styrene-hydrogenated diene), ICI's polymeric surfactants, homopolystyrene, a nonfunctionalized Kraton block polymer, and two Union Carbide Corporation silwet surfactants. The high-molecular-weight sulfonated polystyrene (60,000) containing a low level of sulfonation, functionalized Kraton block polymers, and one ICI polymeric surfactant were effective in improving the dispersion stability of the alumina. The percent of theoretical settling density for the “good” polymeric steric stabilizers ranged from 45 to 50%. The low-molecular-weight sulfonated polystyrene (10,000 MW), homopolystyrene, unfunctionalized Kraton block polymer, one ICI polymeric surfactant, and the silwet surfactants were ineffective in improving the dispersion stability of the alumina in the mixed solvent. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 12 (1985), S. 41-46 
    ISSN: 0148-7280
    Keywords: spermatozoa ; stallion ; crater defect ; electron microscopy ; nuclear ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The appearance of the nuclear abnormality “crater defect” is described in spermatozoa from the domestic horse (Equadae). Under scanning electron microscopy, the defect appears as a severe depression at any area of the sperm nucleus or as a blister or swelling at some point on the sperm nucleus. Ultrastructurally, the crater appears as a nuclear vacuole containing amorphous material similar to that described in bull and boar sperm. The craters ranged in size from 0.5 to 2 μm in diameter. Within ejaculates of stallions having this defect, the percentages of sperm with crater defects varied widely over time, being as high as 60% and as low as 15%.
    Additional Material: 9 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 275-282 
    ISSN: 0148-7280
    Keywords: spermatozoa ; activation ; oviduct ; sperm movements ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Spermatozoa were flushed with mineral oil from the lower isthmus of the rabbit oviduct at four hours postcoitus (pc) and 11 hours pc. Videotapes were made of sperm behavior in the native isthmic fluid and after dilution of the fluid with culture medium. The tapes showed that, initially, spermatozoa in the native isthmic fluid were virtually immotile, but immediately resumed movement on contact with the culture medium. Isthmic sperm motility then evolved over a five- to 10-minute interval into the characteristic biphasic pattern of activated movement. Cine films of isthmic spermatozoa taken with a high-speed camera were analyzed to determine flagellar beat frequency, maximum flagellar curvature, and swimming velocity. Progressiveness ratios and hydrodynamic power outputs were then calculated for individual spermatozoa. Two phases of activated sperm movement, a whiplash phase and a progressive phase, were identified and characterized. The power output of activated spermatozoa increased twentyfold in comparison with the preactivated state. The power output of activated spermatozoa did not differ between the two phases of activated movement.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 339-351 
    ISSN: 0148-7280
    Keywords: spermatozoa ; flow cytometry ; DNA staining ; nuclear morphology ; ultrastructure ; mammals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The morphological and ultrastructural changes that occur during preparation of porcine, bovine, and murine spermatozoa for flow cytometric quantification of the relative DNA content of the X- and Y-chromosome-bearing sperm populations were examined. Ejaculated spermatozoa from the boar and bull were washed using a series of dimethyl sulfoxide (DMSO) solutions prior to fixation, whereas the epididymal mouse spermatozoa were washed only in phosphate-buffered saline (PBS). Spermatozoa from all three species were then fixed in ethanol and processed for fluorochrome staining by a treatment regimen consisting of sulfhydryl reduction and proteolysis. The processed sperm nuclei were stained for DNA with the fluorochrome, 4′-6-diamidino-2-phenylindole (DAPI) before quantification by flow cytometry. Scanning and transmission electron micrographs of sperm heads taken at various steps of the preparation and staining procedures show 1) that the rigorous washing procedure disrupted the plasma and outer acrosomal membranes, 2) that ethanol fixation resulted in removal of the outer membranes and disintegration of the nuclear envelope, and 3) that thiol and proteolysis treatment removed the remaining cellular organelles including the tail and rapidly induced partial decondensation of the tightly packed chromatin. Sequential micrographs showed that the nuclear matrix of all three species increased in thickness about twofold during the preparation and staining. Consequently, the harsh procedures currently used for quantitative staining of DNA for high-resolution flow cytometric analyses destroy most cellular organelles and thereby prevent simultaneous characterization of DNA content and other sperm cell constituents.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 203-212 
    ISSN: 0148-7280
    Keywords: semen ; sperm sorting ; flow analysis ; cell sorter ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A new and improved method of preparing mammalian spermatozoa for high resolution flow cytometric DNA analysis and flow sorting is described. Ejaculated or cryopreserved sperm were briefly sonicated to remove tails and then stained with Hoechst 33342. This simple procedure was found superior to more severe treatments of dimethylsulfoxide washes, fixation in 80% ethanol, and protease digestion of the sperm membranes and tails by papain. Flow cytometric DNA analyses of sperm samples subjected to varying sonication times indicated that X and Y chromosome-bearing sperm populations could be well resolved with as little as 15-sec sonication. In addition, a comparison of sonicated samples stained with four concentrations of bisbenzimide (Hoechst 33342) or 4′,6-diamidino-2-phenylindole (DAPI) indicated that 2.5 or 5.0 μg/ml of Hoechst was sufficient to resolve the X and Y sperm populations. In order to quantitatively describe the flow cytometric data, several indices (sample quality, orientation and splitting) were developed.
    Additional Material: 5 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 16 (1987), S. 193-204 
    ISSN: 0148-7280
    Keywords: sperm penetration ; storage ; semen quality ; swine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of liquid storage and cryopreservation of boar spermatozoa on sperm motility, acrosomal integrity, and the penetration of zona-free hamster (ZFH) ova was examined. The sperm penetration assay (SPA) provides valuable information on specific events of fertilization and is a potentially useful indicator of sperm fertility. Ejaculated semen from 4 boars was subjected to 3 treatments: fresh (FRE, no storage), liquid-stored (LIS, stored at 18°C for 3 days), and frozen (FRO, frozen by pellet method and stored at -196°C for 3 days). A highly motile sperm population was isolated by the swim-up procedure (1 hr). FRE and LIS were incubated an additional 3 hr at 39°C in a Tris-buffered medium to elicit capacitation and the acrosome reaction. Sperm motility and acrosomal integrity were assessed before and after incubation. For the SPA, sperm and eggs were incubated at 39°C for 3 hr in Hams F-10 medium. Each egg was assessed for sperm penetration, sperm binding, and stage of development. Percentages of sperm motility and sperm with a normal apical ridge (NAR) prior to incubation were 78 and 78 (FRE), 75 and 69 (LIS), and 28 and 50 (FRO). After incubation, percentages of motility, NAR, and acrosome-reacted sperm were 34, 10, and 73 (FRE); 43, 24, and 51 (LIS); and 18, 13, and 59 (FRO). A somewhat higher (P 〈 .05) percentage of ZFH ova was penetrated by FRE (45.8) than by LIS (42.0). Penetration of ZFH ova by FRO was markedly (P 〈 .05) reduced (30.2). Sperm penetration was not significantly correlated with motility or acrosomal integrity before or after incubation, regardless of treatment. These data suggest that the SPA can be used in conjunction with conventional measures of semen analysis in assessing the potential fertilizing capacity of boar sperm and that liquid storage is superior to frozen storage with respect to preserving sperm fertility.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 3 (1980), S. 259-266 
    ISSN: 0148-7280
    Keywords: spermatozoa ; boar ; crater defect ; electron microscopy ; nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Nuclear vacuoles resembling the “crater defect” described in bull spermatozoa were observed in 14 boars. Both the incidence of the defect and semen quality were monitored with phase contrast microscopy over a three-month period. The percentages of cratered spermatozoa varied widely both among boars and in ejaculates from the same boar taken on different days. The presence of cratered spermatozoa at a level of 5% or more appeared to be associated with low semen quality. The defect was studied with scanning and transmission electron microscopy and was found to consist of nuclear invaginations, about 0.5 μm in diameter, containing some scanty amorphous electron-dense material. In boars showing a high incidence of spermatozoa with crater defects, abnormalities of the acrosome and perforatorium were common.
    Additional Material: 11 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 21 (1988), S. 335-343 
    ISSN: 0148-7280
    Keywords: flow cytometry ; sperm separation ; DNA ; sex ratio ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Flow cytometric techniques were used to measure relative DNA content of X and Y chromosome-bearing bull, boar, and ram sperm populations and to separate the two sex-determining populations. Neat semen was prepared for flow cytometric analysis by washing, light sonication, and staining with 9 μM Hoechst 33342. Computer analysis of the bimodal histograms showed mean X-Y DNA differences of 3.9, 3.7, and 4.2% for bull, boar, and ram, respectively. Flow cytometric reanalysis of sorted bull, boar, and ram sperm showed purities greater than 90%. Bull, boar, and ram sperm nuclei were microinjected into hamster oocytes. Microinjected sperm were either unsorted, sorted, unsorted plus dithio-threitol (DTT) exposure, or sorted plus DTT exposure. Following microinjection, eggs were incubated 3 hr, fixed, and stained. A total of 579 eggs was observed for sperm activation (decondensation or formation of a male pronucleus). A lower percentage of sorted than unsorted (3 vs. 23%) boar sperm was activated (P 〈.05). However, sorted and unsorted DTT-exposed boar sperm or sorted and unsorted bull or ram sperm, regardless of DTT treatment, did not differ significantly. Sorted sperm nuclei of both rams and bulls exhibited higher activation rates than sorted boar sperm (P 〈.05). Treatment of sperm with DTT increased the activation rate (P 〈 .05) for sorted boar sperm but not for bull or ram sperm. These data represent the first separation of bull, boar, and ram X and Y chromosome-bearing sperm populations and the first evidence that sperm of domestic animals sorted on the basis of DNA by flow cytometric procedures have the ability to decondense and to form pronuclei upon injection into a hamster egg.
    Additional Material: 9 Ill.
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