Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is highly regulated in response to fluctuations in the environment, including changes in irradiance. However, no complex data are available on Rubisco regulatory mechanisms triggered in plants which are submitted to moderate-low irradiance shift. Therefore, we investigated in a comprehensive way the changes at the level of amount of Rubisco protein, its structural organization and carboxylase activity of the holoenzyme as triggered by exposure of moderate irradiance-grown Arabidopsis thaliana plants to low irradiance conditions. An exposure of moderate irradiance-grown plants to low irradiance for a single photoperiod caused the exclusion of a certain pool of Rubisco under altered conditions owing to oxidative modifications resulting in the formation of protein aggregates involving Rubisco large subunit (LS). As a result, both initial and total Rubisco carboxylase activities were reduced, whereas Rubisco activation state remained largely unchanged. The results of the determination of reactive oxygen species indicated that a moderate/low irradiance transition had stimulated (1) O2 accumulation and we strongly suggest that Rubisco oxidative modifications leading to formation of aggregates encompassing Rubisco-LS were triggered by (1) O2 . When moderate irradiance regime was resumed, the majority of Rubisco-LS containing aggregates tended to be resolubilized, and this allowed Rubisco carboxylation activities to be largely recovered, without changes in the activation state of the enzyme. In the longer term, these results allow us to better understand a complexity of Rubisco regulatory mechanisms activated in response to abiotic stresses and during recovery from the stresses.
The paper deals with photometric and morphologic analysis of bioluminescent images obtained by registration of light radiated directly from some plant objects. Registration of images obtained from ultra-weak light sources by the single photon counting (SPC) technique is the subject of this work. The radiation is registered by use of a 16-bit charge coupled device (CCD) camera ,,Night Owl" together with WinLight EG&G Berthold software. Additional application-specific software has been developed in order to deal with objects that are changing during the exposition time. Advantages of the elaborated set of easy configurable tools named FCT for a computer-aided photometric and morphologic analysis of numerous series of quantitatively imperfect chemiluminescent images are described. Instructions are given how to use these tools and exemplified with several algorithms for the transformation of images library. Using the proposed FCT set, automatic photometric and morphologic analysis of the information hidden within series of chemiluminescent images reflecting defensive processes in poinsettia (Euphorbia puicherrima Wilki) leaves affected by a pathogenic fungus Botiytis cinerea is revealed Key words: ultra-weak chemiluminescence, single photon counting imaging, slow scan CCD camera, automatic analysis of a single or series of images, pathogenic fungus Botrytis cinerea, poinsettia Euphorbiapuicherrima Wilid.
Each living cell of a plant produces photons in certain conditions. Under normal physiological conditions, cell photon emission is stationary and minimal.
The fungal genera are known for their high ability to biodeteriorate construction materials. Weight loss and release of calcium are observed when materials, especially concrete, are exposed to fungi. The paper presents the procedures enabling to assess the risk of biocorrosion of buildings at various stages of its development. The presented results lead to selection of effective analytical methodology for this propose. The study was conducted on materials commonly used as construction materials such as granite, ceramic, concrete and plaster. Surfaces of the tested samples were fouled by three selected fungal genera. Changes in properties of the materials due to interaction of fungi have been studied with the use of ergosterol content measurements, microscopic picturing, bioluminescence imaging, measurements of pH and X-ray spectroscopy analysis. Particular attention was paid to propose an appropriate method of estimating the effect of fungi on the surface of building materials using advanced analytical techniques.
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