Low concentrations of NaHSO3 enhance NAD(P)H dehydrogenase-dependent cyclic photophosphorylation and alleviate the oxidative damage to improve photosynthesis in tobacco

Despite the importance of hydrogen peroxide (H2O2) in initiating oxidative damage and its connection to various diseases, the detection of low concentrations of H2O2 (<10 μM) is still limited using current methods, particularly in non-aqueous systems.

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Lycopene andβ-carotene protect against oxidative damage in HT29 cells at low concentrations but rapidly lose this capacity at higher doses

Free Radical Research ◽

10.1080/10715769900300151 ◽

1999 ◽

Vol 30 (2) ◽

pp. 141-151 ◽

Cited By ~ 147

Author(s):

Gordon M. Lowe ◽

Laurence A. Booth ◽

Andrew J. Young ◽

Rodney F. Bilton

Keyword(s):

Oxidative Damage ◽

Ht29 Cells ◽

Low Concentrations ◽

Higher Doses

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Effect of CO2 on Photophosphorylation in vivo as Revealed by the Light-dependent Cl⊖ Uptake in Elodea densa

Zeitschrift für Naturforschung B ◽

10.1515/znb-1967-0816 ◽

1967 ◽

Vol 22 (8) ◽

pp. 873-876 ◽

Cited By ~ 12

Author(s):

W. D. Jeschke ◽

W. Simonis

Keyword(s):

Elodea Densa ◽

Low Concentrations ◽

Cyclic Photophosphorylation ◽

Presence And Absence

The light-dependent Cl⊖ uptake in Elodea densa exhibits dual DCMU inhibition curves dependent on the presence and absence of CO2. This suggests that cyclic photophosphorylation (energy surce in the absence of CO2) is also inhibited by higher concentrations of DCMU in vivo. Further, at low DCMU concentrations the Cl⊖ uptake in the presence of CO2 is much smaller than would be expected if cyclic photophosphorylation were operative. This points to a parallel inhibition of non-cyclic and cyclic photophosphorylations by low concentrations of DCMU in the presence of CO2. The apparent inhibition of cyclic photophosphorylation at low concentrations of DCMU can be reversed by withdrawal of CO2. It is concluded that CO2 may be important in the regulation of cyclic and non-cyclic photophosphorylations in vivo.

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Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077402 ◽

1983 ◽

Vol 41 ◽

pp. 766-767

Author(s):

Eva-Maria Mandelkow ◽

Eckhard Mandelkow ◽

Joan Bordas

Keyword(s):

Electron Microscopy ◽

Dynamic Equilibrium ◽

Time Resolved ◽

X Ray ◽

Additional Information ◽

X Ray Scattering ◽

Low Concentrations ◽

Microtubule Growth ◽

Ray Patterns ◽

Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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Erythrophagocytosis in the Liver in Hemolytic Anemias

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100664 ◽

1968 ◽

Vol 26 ◽

pp. 184-185

Author(s):

O. T. Minick ◽

E. Orfei ◽

F. Volini ◽

G. Kent

Keyword(s):

Acid Phosphatase ◽

Oxidative Damage ◽

Phosphatase Activity ◽

Kupffer Cells ◽

Acid Phosphatase Activity ◽

Common Type ◽

Red Cell ◽

Cell Fragments ◽

Reticulo Endothelial System ◽

Important Site

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).

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The CM120 Biotwin: a high-contrast objective lens, optimum cryo-vacuum and improved EDX performance

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139299 ◽

1995 ◽

Vol 53 ◽

pp. 584-585

Author(s):

Uwe Lücken ◽

Michael Felsmann ◽

Wim M. Busing ◽

Frank de Jong

Keyword(s):

Life Science ◽

Focal Length ◽

Objective Lens ◽

High Contrast ◽

Contrast Imaging ◽

X Ray ◽

Forming Mechanism ◽

Similar Image ◽

High Contrast Imaging ◽

Low Concentrations

A new microscope for the study of life science specimen has been developed. Special attention has been given to the problems of unstained samples, cryo-specimens and x-ray analysis at low concentrations.A new objective lens with a Cs of 6.2 mm and a focal length of 5.9 mm for high-contrast imaging has been developed. The contrast of a TWIN lens (f = 2.8 mm, Cs = 2 mm) and the BioTWTN are compared at the level of mean and SD of slow scan CCD images. Figure 1a shows 500 +/- 150 and Fig. 1b only 500 +/- 40 counts/pixel. The contrast-forming mechanism for amplitude contrast is dependent on the wavelength, the objective aperture and the focal length. For similar image conditions (same voltage, same objective aperture) the BioTWIN shows more than double the contrast of the TWIN lens. For phasecontrast specimens (like thin frozen-hydrated films) the contrast at Scherzer focus is approximately proportional to the √ Cs.

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Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128900 ◽

1987 ◽

Vol 45 ◽

pp. 924-925

Author(s):

F. A. Durum ◽

R. G. Goldman ◽

T. J. Bolling ◽

M. F. Miller

Keyword(s):

Inclusion Bodies ◽

Large Scale ◽

Recombinant Dna ◽

Test System ◽

Cell Protein ◽

Gram Negative Bacteria ◽

Cytoplasmic Inclusions ◽

Isolation And Purification ◽

E Coli ◽

Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

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Phase behavior of cationic and anionic surfactants at low concentrations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123878 ◽

1992 ◽

Vol 50 (1) ◽

pp. 694-695

Author(s):

E. Naranjo

Keyword(s):

Phase Behavior ◽

Structural Characterization ◽

Dynamic Systems ◽

Anionic Surfactants ◽

Intermolecular Forces ◽

Stable Form ◽

Surfactant Mixtures ◽

Low Concentrations ◽

Cationic And Anionic Surfactants ◽

General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

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