1
|
Wang D, Woodcock E, Yang X, Nishikawa H, Sviderskaya EV, Oshima M, Edwards C, Zhang Y, Korchev Y. Exploration of individual colorectal cancer cell responses to H 2O 2 eustress using hopping probe scanning ion conductance microscopy. Sci Bull (Beijing) 2024:S2095-9273(24)00222-6. [PMID: 38644130 DOI: 10.1016/j.scib.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/12/2024] [Accepted: 03/25/2024] [Indexed: 04/23/2024]
Abstract
Colorectal cancer (CRC), a widespread malignancy, is closely associated with tumor microenvironmental hydrogen peroxide (H2O2) levels. Some clinical trials targeting H2O2 for cancer treatment have revealed its paradoxical role as a promoter of cancer progression. Investigating the dynamics of cancer cell H2O2 eustress at the single-cell level is crucial. In this study, non-contact hopping probe mode scanning ion conductance microscopy (HPICM) with high-sensitive Pt-functionalized nanoelectrodes was employed to measure dynamic extracellular to intracellular H2O2 gradients in individual colorectal cancer Caco-2 cells. We explored the relationship between cellular mechanical properties and H2O2 gradients. Exposure to 0.1 or 1 mmol/L H2O2 eustress increased the extracellular to intracellular H2O2 gradient from 0.3 to 1.91 or 3.04, respectively. Notably, cellular F-actin-dependent stiffness increased at 0.1 mmol/L but decreased at 1 mmol/L H2O2 eustress. This H2O2-induced stiffness modulated AKT activation positively and glutathione peroxidase 2 (GPX2) expression negatively. Our findings unveil the failure of some H2O2-targeted therapies due to their ineffectiveness in generating H2O2, which instead acts eustress to promote cancer cell survival. This research also reveals the complex interplay between physical properties and biochemical signaling in cancer cells' antioxidant defense, illuminating the exploitation of H2O2 eustress for survival at the single-cell level. Inhibiting GPX and/or catalase (CAT) enhances the cytotoxic activity of H2O2 eustress against CRC cells, which holds significant promise for developing innovative therapies targeting cancer and other H2O2-related inflammatory diseases.
Collapse
Affiliation(s)
- Dong Wang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Emily Woodcock
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, United Kingdom
| | - Xi Yang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Hiromi Nishikawa
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Elena V Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, United Kingdom
| | - Masanobu Oshima
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan
| | - Christopher Edwards
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Yanjun Zhang
- WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan; Department of Medicine, Imperial College London, London W12 0NN, United Kingdom.
| | - Yuri Korchev
- Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kanazawa 920-1192, Japan.
| |
Collapse
|
2
|
Woodcock E, Gorelkin PV, Goff PS, Edwards CRW, Zhang Y, Korchev Y, Sviderskaya EV. Measuring Melanoma Nanomechanical Properties in Relation to Metastatic Ability and Anti-Cancer Drug Treatment Using Scanning Ion Conductance Microscopy. Cells 2023; 12:2401. [PMID: 37830615 PMCID: PMC10571876 DOI: 10.3390/cells12192401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
A cell's mechanical properties have been linked to cancer development, motility and metastasis and are therefore an attractive target as a universal, reliable cancer marker. For example, it has been widely published that cancer cells show a lower Young's modulus than their non-cancerous counterparts. Furthermore, the effect of anti-cancer drugs on cellular mechanics may offer a new insight into secondary mechanisms of action and drug efficiency. Scanning ion conductance microscopy (SICM) offers a nanoscale resolution, non-contact method of nanomechanical data acquisition. In this study, we used SICM to measure the nanomechanical properties of melanoma cell lines from different stages with increasing metastatic ability. Young's modulus changes following treatment with the anti-cancer drugs paclitaxel, cisplatin and dacarbazine were also measured, offering a novel perspective through the use of continuous scan mode SICM. We found that Young's modulus was inversely correlated to metastatic ability in melanoma cell lines from radial growth, vertical growth and metastatic phases. However, Young's modulus was found to be highly variable between cells and cell lines. For example, the highly metastatic cell line A375M was found to have a significantly higher Young's modulus, and this was attributed to a higher level of F-actin. Furthermore, our data following nanomechanical changes after 24 hour anti-cancer drug treatment showed that paclitaxel and cisplatin treatment significantly increased Young's modulus, attributed to an increase in microtubules. Treatment with dacarbazine saw a decrease in Young's modulus with a significantly lower F-actin corrected total cell fluorescence. Our data offer a new perspective on nanomechanical changes following drug treatment, which may be an overlooked effect. This work also highlights variations in cell nanomechanical properties between previous studies, cancer cell lines and cancer types and questions the usefulness of using nanomechanics as a diagnostic or prognostic tool.
Collapse
Affiliation(s)
- Emily Woodcock
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
| | - Peter V. Gorelkin
- Research Laboratory of Biophysics, National University of Science and Technology MISiS, Moscow 119049, Russia
| | - Philip S. Goff
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
| | | | - Yanjun Zhang
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yuri Korchev
- Department of Medicine, Imperial College London, W12 0NN London, UK (Y.K.)
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Elena V. Sviderskaya
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK; (E.W.)
| |
Collapse
|
3
|
Kolmogorov VS, Erofeev AS, Woodcock E, Efremov YM, Iakovlev AP, Savin NA, Alova AV, Lavrushkina SV, Kireev II, Prelovskaya AO, Sviderskaya EV, Scaini D, Klyachko NL, Timashev PS, Takahashi Y, Salikhov SV, Parkhomenko YN, Majouga AG, Edwards CRW, Novak P, Korchev YE, Gorelkin PV. Mapping mechanical properties of living cells at nanoscale using intrinsic nanopipette-sample force interactions. Nanoscale 2021; 13:6558-6568. [PMID: 33885535 DOI: 10.1039/d0nr08349f] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mechanical properties of living cells determined by cytoskeletal elements play a crucial role in a wide range of biological functions. However, low-stress mapping of mechanical properties with nanoscale resolution but with a minimal effect on the fragile structure of cells remains difficult. Scanning Ion-Conductance Microscopy (SICM) for quantitative nanomechanical mapping (QNM) is based on intrinsic force interactions between nanopipettes and samples and has been previously suggested as a promising alternative to conventional techniques. In this work, we have provided an alternative estimation of intrinsic force and stress and demonstrated the possibility to perform qualitative and quantitative analysis of cell nanomechanical properties of a variety of living cells. Force estimation on decane droplets with well-known elastic properties, similar to living cells, revealed that the forces applied using a nanopipette are much smaller than in the case using atomic force microscopy. We have shown that we can perform nanoscale topography and QNM using a scanning procedure with no detectable effect on live cells, allowing long-term QNM as well as detection of nanomechanical properties under drug-induced alterations of actin filaments and microtubulin.
Collapse
Affiliation(s)
- Vasilii S Kolmogorov
- National University of Science and Technology "MISiS", 4 Leninskiy prospekt, Moscow, 119049, Russian Federation.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Ozelie R, Hansen P, Liguzinski J, Saylor A, Woodcock E. Occupational Therapy Level II Fieldwork Impact on Clinicians: A Preliminary Time Study. Occup Ther Health Care 2018; 32:61-71. [PMID: 29308946 DOI: 10.1080/07380577.2017.1421800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of this preliminary study was to quantify the amount of time clinicians spend at work with and without a student and identify predictors of time spent at work with a student. A quasi-experimental design evaluated 22 occupational therapists that supervised a student. The occupational therapists completed a time log for 3 months without a student and 3 months while supervising a student. A statistically significant difference in overall time spent at work while supervising a student compared to when not supervising a student was found. Clinicians spent an average additional 25 minutes at work per day when supervising a student. Clinician years of experience and time spent without a student were found to be predictive of the time spent at work with a student. The additional time spent at work when supervising a level II fieldwork student should be considered along with all of the documented benefits of supervising a student by potential fieldwork educators.
Collapse
Affiliation(s)
- Rebecca Ozelie
- a Rush University , Department of Occupational Therapy , Chicago , IL , United States
| | - Piper Hansen
- b Shirley Ryan Ability Lab , Chicago , IL , United States
| | - Julia Liguzinski
- a Rush University , Department of Occupational Therapy , Chicago , IL , United States
| | - Amanda Saylor
- a Rush University , Department of Occupational Therapy , Chicago , IL , United States
| | - Emily Woodcock
- a Rush University , Department of Occupational Therapy , Chicago , IL , United States
| |
Collapse
|
5
|
Yates P, Ziegler P, Welsford D, McIvor J, Farmer B, Woodcock E. Spatio-temporal dynamics in maturation and spawning of Patagonian toothfish Dissostichus eleginoides on the sub-Antarctic Kerguelen Plateau. J Fish Biol 2018; 92:34-54. [PMID: 29314006 DOI: 10.1111/jfb.13479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
This study investigated maturation and spawning of Patagonian toothfish Dissostichus eleginoides in the Heard Island and McDonald Islands (HIMI) fishery on the Kerguelen Plateau in the Indian Sector of the Southern Ocean based on gonads and otoliths collected between 2004 and 2015 and using histological analyses and calibration of macroscopic staging criteria. Dissostichus eleginoides at HIMI spawn throughout the austral late autumn and winter months of May-August and spawning activity is concentrated on slopes along the west and south of the plateau around HIMI at depths of 1500-1900 m. Comparison between histological analyses and macroscopic gonad staging indicated that many fish that had spawned, as indicated by the presence of post-ovulatory follicles, returned to a resting stage which was macroscopically indistinguishable from maturing fish. Furthermore, the occurrence of females of all size classes with low gonado-somatic index and low macroscopic gonad stage during the spawning season suggested that a proportion of mature females did not spawn every year. Age-at-maturity estimates, based on the assumption that fish of macroscopic stages ≥2 were mature, decreased between the 2004-2009 and 2010-2015 periods for both sexes. The magnitude of this temporal variation in age at maturity, however, varied between gear types and fishing depths and variable sampling regimes probably influenced these variations. This study highlights the importance of correct interpretation of macroscopic gonad stages and understanding the influence of fishery operations on estimations of life-history parameters.
Collapse
Affiliation(s)
- P Yates
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
| | - P Ziegler
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
| | - D Welsford
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
| | - J McIvor
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
| | - B Farmer
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
- University of Tasmania, Institute of Marine and Antarctic Studies, Private Bag 49, Hobart, Tasmania, Australia
| | - E Woodcock
- Department of the Environment, Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, Australia
- University of Tasmania, Institute of Marine and Antarctic Studies, Private Bag 49, Hobart, Tasmania, Australia
| |
Collapse
|
6
|
Bernardo B, Lin R, Gao X, Kiriazis H, Woodcock E, Matthews V, Febbraio M, Du X, McMullen J. The Potential of Manipulating PI3K Targeted MicroRNAs to Treat Heart Failure. Heart Lung Circ 2010. [DOI: 10.1016/j.hlc.2010.06.795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
7
|
Shilkrut M, Gealekman O, Rosen D, Berke G, Woodcock E, Binah O. Electrophysiologic perturbations and arrhythmogenic activity caused by activation of the Fas receptor in murine ventricular myocytes: role of the inositol trisphosphate pathway. J Cardiovasc Electrophysiol 2001; 12:185-95. [PMID: 11232618 DOI: 10.1046/j.1540-8167.2001.00185.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Experimental evidence suggests a major role for Fas receptor activation in a wide range of myocardial pathologies. Because clinical situations, which are likely to be associated with Fas activation, are accompanied by a variety of ventricular arrhythmias, the major goal of this study was to investigate the ionic mechanisms responsible for these phenomena. METHODS AND RESULTS To delineate the origin of Fas-mediated electrophysiologic perturbations, the transient outward K+ current I(to) and the L-type Ca2+ current I(Ca,L) were studied in murine ventricular myocytes treated with the Fas-activating monoclonal antibody Jo2. Jo2 decreased I(to) (4.36 +/- 1.2 pA/pF vs 17.48 +/- 2.36 pA/pF in control, V(M) = +50 mV; P < 0.001) and increased I(Ca,L) (-13.17 +/- 1.38 pA/pF vs -3.94 +/- 0.78 pA/pF in control, V(M) = 0 mV; P < 0.001). Pretreatment of ventricular myocytes with ryanodine or thapsigargin prevented the electrophysiologic effects of Jo2, suggesting that [Ca2+]i elevation is important for Fas-mediated action. In agreement with our previous studies demonstrating dependence of Fas-based myocyte dysfunction on an intact inositol trisphosphate (1,4,5-IP3) pathway, the effects of Jo2 on I(to) and I(Ca,L) were prevented by the phospholipase C (generates 1,4,5-IP3) blocker U73122, and by xestospongin C (tested with I(to)), a specific blocker of IP3-operated sarcoplasmic reticulum Ca2+ release channels. Furthermore, intracellular perfusion with 1,4,5-IP3, but not with 1,3,4-IP3, caused electrophysiologic effects resembling those of Jo2. CONCLUSION Decreased I(to) and increased I(Ca,L) underlie Fas-induced action potential alterations and arrhythmias in murine ventricular myocytes, effects that appear to be mediated by 1,4,5-IP3-induced intracellular calcium release.
Collapse
Affiliation(s)
- M Shilkrut
- Bruce Rappaport Faculty of Medicine, The Bernard Katz Minerva Center for Cell Biophysics, Technion-Israel Institute of Technology, Haifa
| | | | | | | | | | | |
Collapse
|
8
|
Gao X, Dilley R, Percy E, Follerton M, Woodcock E, Du X. Increased collagen content reduces the risk of post-infarct cardiac rupture in mice that overexpress β2-adrenergic, receptors in the heart. Heart Lung Circ 2000. [DOI: 10.1046/j.1443-9506.2000.06334.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Abstract
Ischemic preconditioning reduces infarct size and improves cardiac function in various species, including mice. The mechanism for ischemic preconditioning protection is not entirely clear and activation of alpha(1B)-adrenergic receptors (AR) is believed to be involved. Transgenic mice expressing constitutively active mutant alpha(1B)-AR in the heart have enhanced alpha(1B)-AR activity and therefore can be used to test the role of alpha(1B)-AR in ischemic preconditioning. Wild-type and transgenic mice were subjected to 30- or 40-min periods of left coronary artery occlusion followed by 60-min reperfusion, or ischemic preconditioning prior to sustained ischemia-reperfusion. Risk and infarct zones were determined by staining with Evans blue and triphenyltetrazolium, respectively, and quantitated digitally. Infarct zone and infarct size were not different between wild-type and transgenic mice, nor was the extent of reduction in infarct size by preconditioning ischemia (wild-type mice: 45+/-3 to 18+/-3%, transgenic mice: 46+/-3 to 19+/-2% of the left ventricle, both P<0.01). Ventricular function was similar between wild-type and transgenic mice with or without ischemia-reperfusion injury. In conclusion, enhanced alpha(1B)-AR activity by cardiac-specific expression of constitutively active mutant alpha(1B)-AR in mice does not mimic ischemic preconditioning to protect against ischemia-reperfusion injury.
Collapse
Affiliation(s)
- X M Gao
- Baker Medical Research Institute, Melbourne, Australia
| | | | | | | |
Collapse
|
10
|
Woodcock E, Nguyen L. The economics of central billing offices. Med Group Manage J 2000; 47:20-5. [PMID: 11067107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The anticipation of economies of scale in physician billing has led many medical practices to consolidate their billing operations. This article analyzes these economies of scale, comparing performance indicators from centralized and decentralized operations. While consolidation provides compliance, control and information, diseconomies of scale can exist in the centralized receivables management process. The authors conclude that physician practices should consider a hybrid approach to billing, thus reaping the benefits of both centralization and decentralization.
Collapse
Affiliation(s)
- E Woodcock
- MGMA's Health Care Consulting Group, Englewood, CO 80112-5306, USA
| | | |
Collapse
|
11
|
Vlachakis ND, Ransom F, Kogosov E, Woodcock E, Alexander N, Maronde RF. Sympathetic activity and cardiac adrenergic receptors in one-kidney, one clip hypertension in rats. Hypertension 1984; 6:654-9. [PMID: 6500672 DOI: 10.1161/01.hyp.6.5.654] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The activity of the sympathetic nervous system, as measured by levels of plasma and cardiac catecholamines and catecholamine metabolites and the function of cardiac alpha- and beta-adrenergic receptors, was evaluated at 3 days and 4 weeks after induction of one-kidney, one clip hypertension (1K1C) in the rat. At 3 days, the plasma level of norepinephrine (NE) was lower in the 1K1C group than the control group (p less than 0.01), whereas epinephrine (E) and the metabolites dihydroxymandelic acid (DOMA), dihydroxyphenylglycol (DOPEG), and normetanephrine (NMN) were similar in both groups. In addition, cardiac content of catecholamines, their metabolites, and adrenergic receptors were similar in both groups. At 4 weeks, plasma levels of NE and DOPEG were lower (p less than 0.01), whereas levels of DOMA and NMN were higher (p less than 0.02 and p less than 0.001, respectively) in the 1K1C group than the control group. Cardiac content of NE (p less than 0.01), and DOPEG (p less than 0.05) was significantly lower, whereas DOMA and NMN were significantly higher (p less than 0.01) in the 1K1C group as compared to controls. In addition, cardiac density of both alpha- and beta-adrenergic receptors was reduced in the 1K1C group, whereas receptor affinities were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
12
|
Abstract
Malate synthase (EC 4.1.3.2) from dark-grown Euglena gracilis was purified to homogeneity by the criterion of polyacrylamide-gel electrophoresis. The enzyme was released from acetate-grown cells by treatment with ultrasonic waves and purified from broken-cell suspensions by high-speed centrifugation and (NH4)2SO4 fractionation, followed by gel-filtration on Sepharose 6B. The final enzyme preparation was purified 190-fold compared with the crude extract. The mol.wt. of the enzyme was about 350000 as determined by gel filtration on Sepharose 6B. Treatment with sodium dodecyl sulphate and urea dissociated the enzyme into subunits of mol.wt. 175000. The pH optimum for the enzyme was 8.0 and the Km values for glyoxylate and acetyl-CoA were 50 and 80 micron respectively. Antibodies raised to the purified enzyme were shown to be monospecific by radiochemical immunoassay. Euglena anti-(malate synthase) tested on Ouchterlony double-diffusion gels gave a sharp precipitation band against acetate-grown Escherichia coli, but no immunological correspondence was observed with acetate-grown Chlorella fusca, Zea mays (maize) scutella or purified malate synthase from Ricinus communis.
Collapse
|
13
|
Beattie JK, Fensom DJ, Freeman HC, Woodcock E, Hill HA, Stokes AM. An NMR investigation of electron transfer in the copper-protein, plastocyanin. Biochim Biophys Acta 1975; 405:109-14. [PMID: 240433 DOI: 10.1016/0005-2795(75)90320-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. The proton NMR spectra of oxidised and reduced French bean plastocyanin have been recorded on a 270 MHz pulsed spctrometer. 2. The spectrum of a mixture containing the protein in the paramagnetic Cu(II) and diamagnetic Cu(I) states is a superposition of the separate spectra. When ferrirate spectra. 3. The results show that self-exchange between Cu(II)- and Cu(I)-plastocyanin is slow on the NMR time scale (kex less than 2-10(4) M-1-s-1 at 50 degrees C), and that electron transfer in the presence of ferricyanide is rapid (k greater than 1-10(5) M-1-s-1).
Collapse
|
14
|
Woodcock E, McGehee T, Grubb C. The blackboard and care plan--nursing treatment tools. J Psychiatr Nurs Ment Health Serv 1972; 10:15-7. [PMID: 4119053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
15
|
|
16
|
Davis RC, Woodcock E. The nursing contract: an alternate in care. J Psychiatr Nurs Ment Health Serv 1971; 9:26-7. [PMID: 4325759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|