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Start Over Coverage 447-453

1. Chloroplast ultrastructural development during the ontogeny of the second leaf of wheat under nitrogen deficiency

Creator:
Kutík, J., Činčerová, A., and Dvořák, M.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
Development of mesophyll cell chloroplasts during ontogeny of second wheat (Triticum aestivum L.) leaf was compared in plants grown in Ml nutrient solution (+N) and in nutrient solution without nitrogen (-N). Chloroplast size and ultrastructure were evaluated quantitatively by means of transmission electron microscopy and stereology. In -N plants compared to +N ones, the life spán of the second leaf was shortened and chloroplast development modified; the most striking feature was the accumulation of starch. Moreover, mature chloroplasts of -N plants were smaller and had smaller relative partial volume of thylakoids and larger relative partial volume of plastoglobules than those of +N plants.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Structural characteristics of extra-membrane domains and guanidine hydrochloride-induced denaturation of photosystem 2 core antenna complexes CP43 and CP47

Creator:
Qu, Y.-G., Gong, Y.-D., Guo, S.-K., Li, L.-B., and Kuang, T.-Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
aromatic amino acid, chlorophyll, circular dichronism, CP43, CP47, denaturation, energy transfer, extramembrane domain, fluorescence, guanidine hydrochloride, and β-carotene
Language:
Multiple languages
Description:
The structural characteristics of the extra-membrane domains and guanidine hydrochloride-induced denaturation of photosystem 2 (PS2) core antenna complexes CP43 and CP47 were investigated using fluorescence emission and circular dichroism (CD) spectra. The extra-membrane domains of CP43 and CP47 possessed a certain degree of secondary and tertiary structure and not a complete random coil conformation. The tertiary structure and the chlorophyll (Chl) a microenvironment of CP47 were more sensitive to guanidine hydrochloride (GuHCl) than that of CP43. Changes in energy transfer from β-carotene to Chl a corresponded well to changes in the tertiary structure while their correlation with changes in the secondary structure was rather poor. Unlike most of water-soluble proteins, both CP43 and CP47 are partly resistant to denaturation induced by guanidine hydrochloride (GuHCl); the denaturation of CP43 or CP47 is not a two-state process. Those features most probably reflect their character as intrinsic membrane proteins. and Y.-G. Qu ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public