scholarly journals Diagnosis of the Earliest Strain-Specific Interactions between Tobacco Mosaic Virus and Chloroplasts of Tobacco Leaves in Vivo by Means of Chlorophyll Fluorescence Imaging

1994 ◽  
Vol 104 (3) ◽  
pp. 1059-1065 ◽  
Author(s):  
S. Balachandran ◽  
C. B. Osmond ◽  
P. F. Daley
Keyword(s):  
Chlorophyll Fluorescence ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Fluorescence Imaging ◽  
Chlorophyll Fluorescence Imaging ◽  
Specific Interactions ◽  
Tobacco Leaves

scholarly journals Lichen Depsides and Depsidones Reduce Symptoms of Diseases Caused by Tobacco Mosaic Virus (TMV) in Tobacco Leaves

2012 ◽  
Vol 7 (5) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Ingrid Ramírez ◽  
Soledad Araya ◽  
Marisa Piovano ◽  
Marcela Carvajal ◽  
Alvaro Cuadros-Inostroza ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Defense Mechanism ◽  
Allene Oxide ◽  
Protective Effects ◽  
Tobacco Leaves ◽  
Lichen Substances ◽  
Plant Defense Mechanism ◽  
Oxide Synthase

Two depsides and five depsidones, isolated from lichens, were tested to determine their in vivo protective effects on tobacco leaves challenged with Tobacco Mosaic Virus (TMV). The results indicate that most of these compounds are able to reduce either the number and/or the size of necrotic lesions following virus infection. Pannarin, 1′-chloro-pannarin and stictic acid provided the more effective protective results, reducing by at least 45% the number and size of lesions. Real Time PCR assays were used to explore the target of action against TMV by examining the response behavior of genes involved in the plant defense mechanism. The application of the lichen substances did not lead to changes in the transcriptional levels of pathogen-related ( PR1a), allene oxide synthase 2 ( AOS2) or oxophytodienoate reductase ( OPR3) genes. Thus, the protection observed in the tobacco leaves treated with the lichen compounds may be mediated by a mechanism which does not involved the SA- or JA-mediated defensive plant response. A possible structure-activity relationship is presented.

scholarly journals Sink-source transition in tobacco leaves visualized using chlorophyll fluorescence imaging

2001 ◽  
Vol 151 (3) ◽  
pp. 585-595 ◽  
Author(s):  
Qingwei Meng ◽  
Katharina Siebke ◽  
Peter Lippert ◽  
Bernhard Baur ◽  
Ute Mukherjee ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Imaging ◽  
Chlorophyll Fluorescence Imaging ◽  
Tobacco Leaves

Photoinhibitory printing on leaves, visualised by chlorophyll fluorescence imaging and confocal microscopy, is due to diminished fluorescence from grana

1999 ◽  
Vol 26 (7) ◽  
pp. 717 ◽  
Author(s):  
Barry Osmond ◽  
Owen Schwartz ◽  
Brian Gunning
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Imaging ◽  
Imaging System ◽  
Confocal Microscope ◽  
Chlorophyll Fluorescence Imaging ◽  
Grid Pattern ◽  
Chlorophyll Autofluorescence ◽  
The Stability ◽  
Living Tissues

By analogy with the starch printing technique, it was hypothesised that photoinhibition could be used to print images on leaves that would be invisible to the eye, but easily revealed by chlorophyll fluorescence imaging. We first illustrate the process of chlorophyll fluorescence printing on leaves of the shade plant, Cissus rhombifolia, using photographs of artefacts from starch printing experiments in the laboratory of Molisch. We then use portraits of current leaders in chlorophyll fluorescence research to demonstrate the stability of these images in living tissues. Text printing from microfilm of Ewart’s pioneering studies in photoinhibition shows the resolution of the method with the fixed-focus, portable, imaging system used here. The stability of images, as well as quenching analysis of images and of leaves, suggests that localised photoinactivation, rather than sustained photoprotection, is responsible for the detail displayed by fluorescence printing. Electron micrograph positives of stained thylakoids can be printed to create an illusion of what is imagined to be the source of chlorophyll fluorescence at the membrane level. Individual chloroplasts in adjacent cells under the grid pattern of granal stacks printed on leaves were also examined using a confocal microscope. Compared with chloroplasts in the shaded parts of the grid, those in the photoinactivated parts of the grid show greatly reduced chlorophyll autofluorescence. Moreover, these chloroplasts have lost the localised bright fluorescence from grana. Comparisons of fluorescence yields show that relative chlorophyll autofluorescence from grana observed in the confocal microscope parallels that determined in leaves. Our experiments provide direct visual evidence that fluorescence from grana is lost following photoinactivation of photosystem II in vivo.

scholarly journals Dual-Modal Magnetic Resonance and Fluorescence Imaging of Atherosclerotic Plaques in Vivo Using VCAM-1 Targeted Tobacco Mosaic Virus

Nano Letters ◽  
2014 ◽  
Vol 14 (3) ◽  
pp. 1551-1558 ◽  
Author(s):  
Michael A. Bruckman ◽  
Kai Jiang ◽  
Emily J. Simpson ◽  
Lauren N. Randolph ◽  
Leonard G. Luyt ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Fluorescence Imaging ◽  
Atherosclerotic Plaques

In vivo assessing flavonols in white grape berries (Vitis vinifera L. cv. Pinot Blanc) of different degrees of ripeness using chlorophyll fluorescence imaging

2007 ◽  
Vol 34 (12) ◽  
pp. 1092 ◽  
Author(s):  
Sándor Lenk ◽  
Claus Buschmann ◽  
Erhard E. Pfündel
Keyword(s):  
Chlorophyll Fluorescence ◽  
Vitis Vinifera ◽  
Radiation Exposure ◽  
Fluorescence Imaging ◽  
Sugar Content ◽  
Chlorophyll Degradation ◽  
Chlorophyll Fluorescence Imaging ◽  
Vitis Vinifera L ◽  
Grape Berries

Exposed and non-exposed halves of field-grown berries of the white grapevine Vitis vinifera L. cv. Pinot Blanc at various stages of ripeness were analysed using chlorophyll fluorescence imaging. The stage of ripeness was classified by the total sugar concentration which ranged between 120 and 300 g L–1 for the different berries but was similar in the exposed and the non-exposed half of individual berries. Fluorescence was excited in the UV-A and the blue spectral region and detected at red as well as far-red wavelengths. At both emission ranges, UV-excited fluorescence was weak and required correction for the contribution of small false signals. After correction, in vivo UV screening by berry skins was derived from the ratio of UV-A to blue-excited fluorescence intensities, and a relationship between in vivo UV screening and flavonol quantity was established: the quantity of flavonols was determined by spectral analysis of extracted phenolics. Significantly high flavonol concentrations, and effective in vivo UV screening, were detected in most exposed half-berries at sugar concentrations higher than 200 g L–1 but not in non-exposed samples. This suggests that radiation-exposure conditions determine flavonol synthesis. Based on the absence of flavonol accumulation in exposed half-berries with sugar concentrations smaller than 200 g L–1, however, it is suggested that berries need to arrive at an advanced stage of ripeness before responding to radiation-exposure by synthesising large amounts of UV-protecting flavonols. Chlorophyll degradation, which was followed by blue-excited intensities of far-red fluorescence, progressed in parallel with increasing sugar content suggesting that chlorophyll degradation is associated with berry ripening. In addition, exposure to sunlight appeared to slightly stimulate chlorophyll decay.

Nitroxyl Modified Tobacco Mosaic Virus as a Metal-Free High-Relaxivity MRI and EPR Active Superoxide Sensor

2018 ◽  
Author(s):  
Madushani Dharmarwardana ◽  
André F. Martins ◽  
Zhuo Chen ◽  
Philip M. Palacios ◽  
Chance M. Nowak ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Single Molecule ◽  
Biological Fluids ◽  
Cellular Respiration ◽  
Organic Radical ◽  
Paramagnetic Resonance ◽  
Metal Free ◽  
Disease States

Superoxide overproduction is known to occur in multiple disease states requiring critical care yet non-invasive detection of superoxide in deep tissue remains a challenge. Herein, we report a metal-free magnetic resonance imaging (MRI) and electron paramagnetic resonance (EPR) active contrast agent prepared by “click conjugating” paramagnetic organic radical contrast agents (ORCAs) to the surface of tobacco mosaic virus (TMV). While ORCAs are known to be reduced <i>in vivo</i> to an MRI/EPR silent state, their oxidation is facilitated specifically by reactive oxygen species—in particular superoxide—and are largely unaffected by peroxides and molecular oxygen. Unfortunately, single molecule ORCAs typically offer weak MRI contrast. In contrast, our data confirm that the macromolecular ORCA-TMV conjugates show marked enhancement for <i>T<sub>1</sub></i> contrast at low field (<3.0 T), and <i>T<sub>2</sub></i> contrast at high field (9.4 T). Additionally, we demonstrated that the unique topology of TMV allows for “quenchless fluorescent” bimodal probe for concurrent fluorescence and MRI/EPR imaging, which was made possible by exploiting the unique inner and outer surface of the TMV nanoparticle. <a>Finally, we show TMV-ORCAs do not respond to normal cellular respiration, minimizing the likelihood for background, yet still respond to enzymatically produced superoxide in complicated biological fluids like serum.</a>

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