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  • Polymer and Materials Science  (5)
  • cadmium  (3)
  • Wiley-Blackwell  (8)
  • American Society of Hematology
  • Institute of Physics
  • Springer Nature
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  • Wiley-Blackwell  (8)
  • American Society of Hematology
  • Institute of Physics
  • Springer Nature
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  • 1
    Electronic Resource
    Electronic Resource
    The calcium-induced curvature reversal of rat sperm is potentiated by cAMP and inhibited by anti-calmodulin (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 20 (1991), S. 316-324 
    Details
    ISSN: 0886-1544
    Keywords: sperm motility ; cadmium ; flagellar curvature ; kinase A ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rat sperm, demembranated with 0.1% Triton X-100, were used to explore the reversal in flagellar curvature induced by calcium ion. As reported earlier (Lindemann and Goltz, Cell Motil. Cytoskeleton, 10:420-431, 1988), the radius of curvature of the flagellar midpiece of rat sperm is controlled by the free Ca2+ concentration. A reversal of the direction of curvature (judged by the asymmetric sperm head) takes place at ≈ 2.5 + 10-6 M free Ca2+.In our current study, the time course of the curvature change, after elevating free Ca2+ to 3.5 ± 10-4 M, was utilized to assess the effects of the cAMP-kinase A pathway on the calcium response. In addition, calmodulin's involvement in this response was explored using anti-calmodulin and Cd2+. The activity state of the sperm models (which could be directly influenced through cAMP) was found to control the rate of curvature change in response to increased free Ca2+. In the most extreme case, fully quiescent sperm did not respond to Ca2+ at all, and cAMP-primed sperm models completed the response to Ca2+ in two minutes or less.Anti-calmodulin demonstrated strong inhibitory effects on the curvature reversal. Cadmium ion was also extremely potent at blocking the response to Ca2+, completely eliminating the curvature reversal at 2 × 10-10 M free Cd2+.Based on these findings, it appears that the Ca2+-activated curvature reversal of rat sperm is potentiated by cAMP-dependent kinase and may be mediated through calmodulin.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970200407
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  • 2
    Electronic Resource
    Electronic Resource
    Inhibition of microtubule sliding by Ni2+ and Cd2+: Evidence for a differential response of certain microtubule pairs within the bovine sperm axoneme (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 66-76 
    Details
    ISSN: 0886-1544
    Keywords: nickel ; cadmium ; dynein ; motility ; flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Bovine sperm, extracted with 0.1% Triton X-100, frozen at -20°C for 48-120 hours, and thawed, disintegrated by microtubule sliding when 1 mM MgATP was added. Microtubules and outer dense fibers (ODFs) were usually extruded in groups or “bundles.” A total of 44.5% of the cells extruded two distinct bundles, one from each side of the connecting piece, exhibiting opposite curvatures. Only one bundle was observed in 46.2% of the cells, and 9.2% showed no signs of sliding. Transmission electron microscopy (T.E.M.) showed one group consisting of the 4,5-6,7 elements, with the 9,1,2 elements on the other side of the axoneme making up the other bundle. T.E.M. revealed that when only one side of the axoneme had extruded elements, they were always from the 4,5-6,7 group. The remainder of the axoneme (8,9,1,2,3 and the central pair) was left relatively intact, suggesting a difference in the sliding response of the nine pairs of axonemal microtubules. These results indicate a predisposition for sliding between elements 7 and 8 over that between doublets 2 and 3, perhaps due to a disparity in activation thresholds. Also, both Ni2+ and Cd2+ appear to selectively block activation of 2-3 interdoublet sliding.Incubation with 0.25 mM Ni2+ prior to adding MgATP modified the percentages of sliding patterns: 8.6% demonstrated two-sided extrusion, 58.2% showed one-sided, and 33.2% had no extruded bundles. Again, when half the axoneme was missing, it was always the 4,5-6,7 group. Ten micromolar Cd2+ altered the sliding pattern similarly to Ni2+, with 28% two-sided extrusion, 55.9% one-sided extrusion and 16.1% with no extruded bundles.Either pretreatment regimen impeded extrusion of the 9,1,2 group in a high percentage of cells, compared to untreated cells. This specific inhibition of the 9,1,2 side by Ni2+ or Cd2+ is especially significant since Ni2+ also inhibits spontaneous wave initiation in bull sperm (Lindemann et al.: Journal of Cell Biology 87:420-426, 1980), and both Ni2+ and Cd2+ reportedly block the flagellar Ca2+-response in rat sperm (Lindemann and Goltz: Cell Motility and the Cytoskeleton 10:420-431, 1988; Lindemann et al.: Cell Motility and the Cytoskeleton 20:316-324, 1991). © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260107
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  • 3
    Electronic Resource
    Electronic Resource
    Calcium regulation of flagellar curvature and swimming pattern in triton X-100-extracted rat sperm (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 420-431 
    Details
    ISSN: 0886-1544
    Keywords: sperm motility ; hyperactivation ; vanadate ; nickel ; cadmium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Free Ca2+ changes the curvature of epididymal rat sperm flagella in demembranated sperm models. The radius of curvature of the flagellar midpiece region was measured and found to be a continuous function of the free Ca2+ concentration. Below 10-7 M free Ca2+, the sperm flagella assumed a pronounced curvature in the same direction as the sperm head. The curvature reversed direction at 2.5 × 10-6 M Ca2+ to assume a tight, hook-like bend at concentrations of 10-5 to 10-4 M free Ca2+. Sodium vanadate at 2 × 10-6 M blocked flagellar motility, but did not inhibit the Ca2+-mediated change in curvature. Nickel ion at 0.2 mM and cadmium ion at 1 μM interfered with the transition and induced the low Ca2+ configuration of the flagellum. The forces that maintain the Ca2+-dependent curvature are locally produced, as dissection of the flagella into segments did not significantly alter the curvature of the excised portions. Irrespective of the induced pattern of curvature, the sperm exhibited coordinated, repetitive flagellar beating in the presence of ATP and cAMP. At 0.3 mM ATP the flagellar waves propagated along the principal piece while the level of free Ca2+ controlled the overall curvature. When Ca2+-treated sperm models with hooked midpieces were subjected to higher concentrations of ATP (1-5 mM), some cells exhibited a pattern of movement similar to hyperactivated motility in capacitated live sperm. This type of motility involved repetitive reversals of the Ca2+-induced bend in the midpiece, as well as waves propagated along the principal piece. The free Ca2+ available to the flagellum therefore appeared to modify both the pattern of motility and the flagellar curvature.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100309
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  • 4
    Electronic Resource
    Electronic Resource
    Handbuch der zerstörungsfreien Materialprüfung. E. A. W. Müller. Dritte Lieferung mit 1153 Bildern, 69 Tafeln im Text und einem Anhang: Wellenlängen- und Winkeltafeln für die Röntgenspektralanalyse. Verlag: R. Oldenbourg München, 1963. Preis 168, -  DM (1964)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 15 (1964), S. 701-701 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19640150817
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  • 5
    Electronic Resource
    Electronic Resource
    Proton transfer and polarizability of hydrogen bonds in proteins coupled with conformational changes. I. Infrared investigation of poly(glutamic acid) with various N Bases (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 2407-2418 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of hydrogen bonds formed between carboxylic acid residues and histidine residues in proteins is studied by ir spectroscopy. Poly(glutamic acid) [(Glu)n] is investigated with various monomer N bases. The position of the proton transfer equilibrium OH…N ⇌ O-…H+N is determined considering the bands of the carboxylic group.It is shown that largely symmetrical double minimum energy surfaces are present in the OH…N ⇌ O-…H+N bonds when the pKa of the protonated N base is two values larger than that of the carboxylic groups of (Glu)n. Hence OH…N ⇌ O-…H+N bonds between glutamic and aspartic acid residues and histidine residues in proteins may be easily polarizable proton transfer hydrogen bonds. The polarizability of these bonds is one to two orders of magnitude larger than usual electron polarizabilities; therefore, these bonds strongly interact with their environment.It is demonstrated that water molecules shift these proton transfer equilibria in favor of the polar proton boundary structure. The access of water molecules to such bonds in proteins and therefore the position of this proton transfer equilibrium is dependent on conformation.The amide bands show that (Glu)n is α-helical with all systems. The only exception is the (Glu)n-n-propylamine system. When this system is hydrated (Glu)n is α-helical, too. When it is dried, however, (Glu)n forms antiparallel β-structure. This conformational transition, dependent on degree of hydration, is reversible. An excess of n-propylamine has the same effect on conformation as hydration.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360161106
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  • 6
    Electronic Resource
    Electronic Resource
    Proton transfer in and polarizability of hydrogen bonds coupled with conformational changes in proteins. II. IR investigation of polyhistidine with various carboxylic acids (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 1285-1304 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyhistidine-carboxylic acid systems are studied by ir spectroscopy. It is shown that OH⃛N ⇌ O-…H+N bonds formed between carboxylic groups and histidine residues are easily polarizable proton-transfer hydrogen bonds when the pKa of the protonated histidine residues is about 2.8 units larger than that of the carboxylic groups. From these results it bis concluded that OH⃛N ⇌ O-⃛H+N bonds between glutamic or aspartic acid histidine residues in proteins may be easily polarizable proton-transfer bonds. Furthermore, it is demonstrated that water molecules shift the proton-transfer equilibria in these hydrogen bonds in favor of the polar structure, i.e., due to water or polar environments OH⃛N ⇌ O- ⃛H+N bonds with smaller ΔpKa values become easily polarizable proton-transfer hydrogen bonds. A consideration of the amide bands of polyhistidine shows that it can be present in five different conformations. It is shown that these conformational changes are strongly related to the degree of proton transfer. Hence, the degree of proton transfer, the degree of hydration, and conformation are not independent of each other, but are strongly coupled. Further proof for the interdependence of proton transfer and conformational changes are hysteresis effects, which are observed with studies of polyhistidine dependent on carboxylic acid, adsorption and desorption. OH⃛N ⇌ O-⃛H+N bonds between aspartic and glutamic acid and histidine residues are present in hemoglobin, in ribonucleases, and in proteases, whereby this type of bond is preferentially found in the active centers of these enzymes. It is pointed out that hydrogen bonds with such interaction properties should be of great significance for structure and especially functions of proteins in which they are present.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360170514
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  • 7
    Electronic Resource
    Electronic Resource
    Pyrolysis of poly(methyl methacrylate co ethyl acrylate) (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 445-453 
    Details
    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: An investigation of the behavior of poly(methyl methacrylate co ethyl acrylate) with a commercially available filament-type pyrolysis unit and gas chromatogaph was conducted. It has been hypothesized that the quantity of ethyl acrylate monomer produced under the conditions of the experiment is dependent upon the number of ethyl acrylate-methyl methacrylate bonds contained in the copolymer. These observations were made possible by a standardized samples-handling technique in which a uniformsize disk was pyrolyzed at a maximum pyrolysis temperature of 600°C. This enabled reproducible pyrolysis gas chromatograms to be obtained and permitted pyrolysis products of copolymers containing different ratios of ethyl acrylate and methyl methacrylate to be compared. An examination of sequence distribution data, obtained with the aid of a sequence distribution program for copolymers, showed sufficient agreement with the pyrolysis data to support the hypothesis. It has been demonstrated that pyrolysis gas chromatography may be applied to experimentally determine the sequence distribution of copolymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150217
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  • 8
    Electronic Resource
    Electronic Resource
    A study of chain transfer in homologous vinyl estersPresented at the 131st Meeting of the American Chemical Society, Miami, Florida, April 7 to 12, 1957. (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 485-498 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The principal complication arising out of free radical-initiated polymerizations involving vinyl acetate has been the chain transfer to monomer and polymer which results in a highly branched polymer chain. Some evidence has also been presented to show that the degree of branching in polyvinyl esters increases with an increasing number of carbon atoms in the vinyl ester. It was of interest, therefore, to obtain a relative measure of the chain transfer constants for successive members of the homologous series of vinyl esters and to relate the constants to the actual structure of the respective polyvinyl ester. Accordingly, the study of the chain transfer in the benzoyl peroxideinitiated polymerizations of vinyl acetate in the presence of a homologous series of ethyl esters of fatty acids was made. Chain transfer constants versus number of carbon atoms in the carboxylate portion of the fatty acid ester resulted in a linear relationship which can be expressed as \documentclass{article}\pagestyle{empty}\begin{document}$$C_{tr,s} = 4.0 \times 10^{ - 3} + n \times 0.7 \times 10^{ - 3}$$\end{document} where n is the number of non-α-methylene groups in the side chain. A concurrent study of the influence of monomer chain lengths of selected vinyl esters on molecular weight of the derived homopolymer was also carried out. The results obtained provide a basis for predicting the trends for changes in branching and degree of polymerization within the homologous series of vinyl esters.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1202811802
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