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Schiller J, Arnhold J, Glander HJ, Arnold K. Lipid analysis of human spermatozoa and seminal plasma by MALDI-TOF mass spectrometry and NMR spectroscopy - effects of freezing and thawing. Chem Phys Lipids 2000; 106:145-56. [PMID: 10930566 DOI: 10.1016/s0009-3084(00)00148-1] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In the present study, the applicability of proton NMR spectroscopy and matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) to the analysis of the lipid composition of human spermatozoa and seminal fluids as well as changes after cryopreservation of human spermatozoa was investigated. Whereas NMR spectra primarily indicated a high content of double bonds within the spermatozoa but no marked differences upon cryopreservation, MS detected intense peaks which could be assigned to phosphatidylcholines containing one docosahexaenoic and one palmitic or stearic acid residue (m/z=806 and 834). In contrast, the seminal plasma contained more saturated fatty acids and especially more sphingomyelin (SM). A freezing/thawing cycle markedly influences the lipid composition of spermatozoa. There was a diminution of phosphatidylcholines (16:0, 22:6 and 18:0, 22:6) and SM (16:0) and the appearance of lysophosphatidylcholines (16:0 and 18:0) and ceramide (16:0). These data demonstrate the release or activation of both phospholipase A(2) and sphingomyelinase in human spermatozoa due to the freezing/thawing cycle. These results were finally confirmed by experiments on the action of phospholipases on lipids containing docosahexaenoic acid.
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Schiller J, Benard S, Reichl S, Arnhold J, Arnold K. Cartilage degradation by stimulated human neutrophils: reactive oxygen species decrease markedly the activity of proteolytic enzymes. CHEMISTRY & BIOLOGY 2000; 7:557-68. [PMID: 11048947 DOI: 10.1016/s1074-5521(00)00013-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Although neutrophilic granulocytes clearly contribute to cartilage degradation in rheumatic diseases, it is unclear if reactive oxygen species (ROS) or proteolytic enzymes are the most important components in cartilage degradation and how they interact. RESULTS Neutrophils were stimulated by chemicals conferring a different degree of ROS formation and enzyme release. Supernatants of neutrophils were incubated with thin slices of pig articular cartilage. Supernatants of cartilage were assayed by NMR spectroscopy, MALDI-TOF mass spectrometry and relevant biochemical methods. Stimulation conditions of neutrophils correlated well with the extent of cartilage degradation. Due to the release of different enzymes, cartilage degradation could be best monitored by NMR since mainly low-mass degradation products were formed. Astonishingly, the suppression of the formation of ROS resulted in decreased cartilage degradation. CONCLUSION ROS formed by neutrophils are not directly involved in cartilage degradation but influence the activity of proteolytic enzymes, which are the main effectors of cartilage degradation.
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Huster D, Arnold K, Gawrisch K. Strength of Ca(2+) binding to retinal lipid membranes: consequences for lipid organization. Biophys J 2000; 78:3011-8. [PMID: 10827979 PMCID: PMC1300884 DOI: 10.1016/s0006-3495(00)76839-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There is evidence that membranes of rod outer segment (ROS) disks are a high-affinity Ca(2+) binding site. We were interested to see if the high occurrence of sixfold unsaturated docosahexaenoic acid in ROS lipids influences Ca(2+)-membrane interaction. Ca(2+) binding to polyunsaturated model membranes that mimic the lipid composition of ROS was studied by microelectrophoresis and (2)H NMR. Ca(2+) association constants of polyunsaturated membranes were found to be a factor of approximately 2 smaller than constants of monounsaturated membranes. Furthermore, strength of Ca(2+) binding to monounsaturated membranes increased with the addition of cholesterol, while binding to polyunsaturated lipids was unaffected. The data suggest that the lipid phosphate groups of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) in PC/PE/PS (4:4:1, mol/mol) are primary targets for Ca(2+). Negatively charged serine in PS controls Ca (2+) binding by lowering the electric surface potential and elevating cation concentration at the membrane/water interface. The influence of hydrocarbon chain unsaturation on Ca(2+) binding is secondary compared to membrane PS content. Order parameter analysis of individual lipids in the mixture revealed that Ca(2+) ions did not trigger lateral phase separation of lipid species as long as all lipids remained liquid-crystalline. However, depending on temperature and hydrocarbon chain unsaturation, the lipid with the highest chain melting temperature converted to the gel state, as observed for the monounsaturated phosphatidylethanolamine (PE) in PC/PE/PS (4:4:1, mol/mol) at 25 degrees C.
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Reichl S, Arnhold J, Knight J, Schiller J, Arnold K. Reactions of pholasin with peroxidases and hypochlorous acid. Free Radic Biol Med 2000; 28:1555-63. [PMID: 10927181 DOI: 10.1016/s0891-5849(00)00268-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability of myeloperoxidase (MPO) and horseradish peroxidase (HRP) to induce chemiluminescence (CL) in Pholasin (Knight Scientific, Plymouth, UK), the photoprotein of the Common Piddock Pholas dactylus, was studied. The oxidation of Pholasin by compound I or II of HRP induced an intense light emission, whereas native HRP showed only a small effect. The luminescence observed upon incubation of Pholasin with native MPO was diminished by preincubation with catalase. Considering the high instability of diluted MPO, it is concluded that traces of hydrogen peroxide in water converted MPO to its active forms, compound I and/or II, which are able to oxidize Pholasin. Indeed, the addition of hydrogen peroxide to a mixture of MPO and Pholasin induced an intense burst of light. This emission was enhanced in degree and duration in the absence of chloride. Hypochlorous acid, the reaction product of Cl(-) and compound I of MPO, was itself able to elicit a luminescent response in Pholasin and this luminescence was strongly inhibited by methionine and taurine. However, both of these HOCl scavengers only slightly reduced the light emission induced by MPO/H(2)O(2) in both the presence or absence of chloride. Thus, hypochlorous acid produced by the MPO/H(2)O(2)/Cl(-) system, under the conditions described in this study, did not contribute to Pholasin luminescence. The Pholasin luminescence elicited by formyl-leucyl-methionyl-phenylalanine (fMLP)-stimulated neutrophils depends both on superoxide anion radicals and higher oxidation states of myeloperoxidase (but not on hypochlorous acid). This is shown by the inhibition of luminescence with superoxide dismutase and potassium cyanide, together with the lack of effect of both methionine and taurine. The luminescence response is about eight times greater in cells stimulated with fMLP/cytochalasin B than with fMLP alone.
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: new insight into development of Paget's disease of the breast. J Natl Cancer Inst 2000; 92:589B-B. [PMID: 10772663 DOI: 10.1093/jnci/92.8.589b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: accuracy of death certificates of prostate cancer patients questioned. J Natl Cancer Inst 2000; 92:589A-A. [PMID: 10772662 DOI: 10.1093/jnci/92.8.589a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K. MEMORANDUM FOR: Science Writers and Editors on the Journal Press List: Breast Cancer Diagnosed in Older Women Is Often Less Aggressive. J Natl Cancer Inst 2000. [DOI: 10.1093/jnci/92.7.507a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Arnold K. MEMORANDUM FOR: Science Writers and Editors on the Journal Press List: Computer Simulation Shows Endoscopic Screening for Colorectal Cancer Could Result in Overall Cost Savings. J Natl Cancer Inst 2000. [DOI: 10.1093/jnci/92.7.507b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K. MEMORANDUM FOR: Science Writers and Editors on the Journal Press List: Inactivation of the BRCA1 Gene May Play a Role in Nonhereditary Breast and Ovarian Cancers. J Natl Cancer Inst 2000. [DOI: 10.1093/jnci/92.7.507c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: study of adult twins shows tendency to develop moles has a strong genetic component. J Natl Cancer Inst 2000; 92:437A-A. [PMID: 10716950 DOI: 10.1093/jnci/92.6.437a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: new measurements show that a protein involved in vitamin A metabolism is missing in 24% of breast cancers. J Natl Cancer Inst 2000; 92:437B-B. [PMID: 10716951 DOI: 10.1093/jnci/92.6.437b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: adding radiotherapy to chemotherapy does not improve disease-free or overall survival of rectal cancer patients. J Natl Cancer Inst 2000; 92:357A-A. [PMID: 10699058 DOI: 10.1093/jnci/92.5.357a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: limited potential for human papillomavirus (HPV) testing for women with low-grade pap smears. J Natl Cancer Inst 2000; 92:357B-B. [PMID: 10699059 DOI: 10.1093/jnci/92.5.357b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zschörnig O, Paasche G, Thieme C, Korb N, Fahrwald A, Arnold K. Association of lysozyme with phospholipid vesicles is accompanied by membrane surface dehydration. Gen Physiol Biophys 2000; 19:85-101. [PMID: 10930141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Lysozyme is a globular protein which is known to bind to negatively charged phospholipid vesicles. In order to study the relationship between binding of the protein and the subsequent destabilization of the phospholipid vesicles a set of experiments was performed using phospholipid monolayers and vesicles. Using microelectrophoresis the binding of lysozyme to phospholipid vesicles made of PS was determined. At low ionic strength and mild acidic pH of the solution lysozyme reduced the magnitude of the negative zeta potential of PS vesicles at lower concentrations compared to neutral pH and high ionic strength. In contrast, the bound fraction of lysozyme to PS vesicles was nearly constant at acidic and neutral pH. At low pH, the binding of lysozyme was accompanied by a strong aggregation of the vesicles. Lysozyme binding to PS vesicles is accompanied by its penetration into the PL monolayer. This was measured by surface tension and film balance measurements at low pH and low ionic strength. The interaction of lysozyme with negatively charged vesicles lead to a decrease of the vesicle surface hydration as measured by the shift of the emission peak of the fluorescent probe DPE. The binding of bis-ANS increased at low pH after addition of lysozyme to the vesicles. This indicates that more hydrophobic patches of the lysozyme-PS complex are exposed at low pH. At low pH the binding process of lysozyme to PS vesicles was followed by an extensive intermixing of phospholipids between the aggregated vesicles, accompanied by a massive leakage of the aqueous content of vesicles.
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list : genetic similarity found between ductal carcinomas In situ and their recurrences. J Natl Cancer Inst 2000; 92:287A-A. [PMID: 10675366 DOI: 10.1093/jnci/92.4.287a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: phone call reminder increases likelihood of mammography. J Natl Cancer Inst 2000; 92:175B-B. [PMID: 10655424 DOI: 10.1093/jnci/92.3.175b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list: No advantage found for high-dose chemotherapy in high-risk breast cancer. J Natl Cancer Inst 2000; 92:175A-A. [PMID: 10655423 DOI: 10.1093/jnci/92.3.175a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list : genetics may explain Women's higher risk of smoking-related lung cancer. J Natl Cancer Inst 2000; 92:1A-A. [PMID: 10620619 DOI: 10.1093/jnci/92.1.1a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Haensler M, Arnold K. Investigation of the effect of freezing on protease-catalyzed peptide synthesis using cryoprotectants and frozen organic solvent. Biol Chem 2000; 381:79-83. [PMID: 10722054 DOI: 10.1515/bc.2000.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In order to investigate the effect of freezing on aqueous protease-catalyzed peptide synthesis systems, the influence of polyethylene glycols as cryoprotecting substances on alpha-chymotrypsin-catalyzed coupling of a N-protected acyl donor ester and various nucleophilic amino components was studied. Changes in S'-specificity of alpha-chymotrypsin in frozen aqueous systems were suppressed by polyethylene glycols even at concentrations below 1% (w/v). Furthermore, the influence of freeze-concentration in organic solvents on protease-catalyzed peptide synthesis was investigated for the first time. In frozen tert-butanol, alpha-chymotrypsin-catalyzed peptide synthesis took advantage from freeze-concentration, but in contrast to frozen aqueous systems, no changes in S'-specificity of the biocatalyst were observed. The results suggest that freeze-concentration is not the only cause of freezing-induced yield improvement in aqueous peptide synthesis systems, but interactions between enzyme and ice structures strongly contribute to the observed effects.
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Binder H, Köhler G, Arnold K, Zschörnig O. pH and Ca2+ dependent interaction of Annexin V with phospholipid membranes: a combined study using fluorescence techniques, microelectrophoresis and infrared spectroscopy. Phys Chem Chem Phys 2000. [DOI: 10.1039/b003033n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list : chemotherapy plus radiation therapy improves survival in patients with oropharyngeal cancer. J Natl Cancer Inst 1999; 91:2063A-A. [PMID: 10601367 DOI: 10.1093/jnci/91.24.2063a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arnold K, Eckstein D. MEMORANDUM FOR: science writers and editors on the journal press list : BRCA mutations should not influence adjuvant therapy decisions for breast cancer. J Natl Cancer Inst 1999; 91:2063B-B. [PMID: 10601368 DOI: 10.1093/jnci/91.24.2063b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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