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Start Over Coverage 99-105

3. Comparison of the primary events of photoinhibition in Cyanobacteriay green algae and thylakoids of higher plants

Creator:
Etienne, A.-L. and Kirilovsky, D.
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
In whole cells of the wild type of Synechocystis 6714 exposed to high irradiance (Hl) the electron transfer to Qb was inhibited before the transfer to Qa In the mutant AzV with two point mutations in the Qg pocket (Ala 251 Val and Phe 211 Ser) the inhibition of electron transport to Qb had about the same rate as in the wild type but the transport to Qa was inhibited faster in the mutant. In the mutant also the repair of photosystem 2 (PS 2) reaction centres was slower after a moderate photoinhibitory damage. In contrast degradation of the Dl protein in the course of photoinhibition in vitro was slower with thylakoids from the mutant than with those of the wild type. In CMamydomonas cells photoinhibited at low temperature (5 °C) and in spinách thylakoids under anaerobic conditions a fast inhibition of electron transfer developed in PS 2 simultaneously with a State characteiized by a high level of F^. This high fluorescent statě disappeared and electron transport activity was restored in the dark without protein synďiesis when photoinhibited samples were soon transferred to higher temperature (25 °C) or to aerobic conditions, respectively. On the other hand, the irreversible photoinhibitory damage characteiized by the dechne of was slowed down by lowering of the temperature in all the objects tested.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Differential sensitivity of stomatal and non-stomatal components to NaCl or Na2SO4 salinity in horsegram, Macrotyloma uniflorum (Lam.)

Creator:
Sreenivasulu Reddy, P., Ramanjulu, S., Sudhakar, C., and Veeranjaneyulu, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
CO2 fixation, NADP-glyceraldehyde-3-phosphate dehydrogenase, photosystem 2 activity, ribose-5-phosphate isomerase, ribulose-1,5-bisphosphate carboxylase, ribulose-5-phosphate kinase, salt stress, and stomatal conductance
Language:
Multiple languages
Description:
14CO2 assimilation rate (P), leaf diffusive conductance (gs), photosynthetic electron flow, and activities of enzymes of Calvin cycle were studied in a horsegram [Macrotyloma uniflorum (Lam.)] in response to salinity induced by NaCl or Na2SO4. A significant reduction in P and gs by both salt treatments was registered. Na2SO4 caused a greater reduction in gs than the NaCl salinity. Studies with isolated chloroplasts confirmed a greater sensitivity to NaCl than to Na2SO4. Salinity inhibited the photosynthetic electron transport. The activity of ribulose-1,5-bisphosphate carboxylase (E.C.4.1.1.39) was under salinity inhibited more than the activities of other three enzymes of the Calvin cycle, ribulose-5-phosphate kinase (E.C.2.7.1.19), ribose-5-phosphate isomerase (E.C.5.3.16), and NADP-glyceraldehyde-3-phosphate dehydrogenase (E.C.1.2.13). These inhibitions lead to a reduced capacity for ribulose-1,5-bisphosphate regeneration. Isolated chloroplasts extracted from salt stressed plants and supplemented with the substrates of Calvin cycle could elevate P, but the P was always lower than in the controls. Decreased P in horsegram exposed to high salinity can be attributed to both stomatal and non-stomatal components, however, the sensitivity to the salt source, NaCl or Na2SO4, was different. and P. Sreenivasulu Reddy ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Nové definice některých základních jednotek měření v soustavě SI

Creator:
Svoboda, Pavel
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
metrologie, mezinárodní soustava jednotek SI, fyzikální veličiny, metrology, international metric system, physical quantities, 6, and 53
Language:
Czech
Description:
Přírodní vědy dnes již dosáhly takové úrovně poznání, že je možno přiblížit se ke konečnému cíli metrologie, totiž vztáhnout veškeré měření a vážení k základním přírodním konstantám, invariantním v místě i čase. Má-li přitom zůstat zachována stávající osvědčená Mezinárodní soustava jednotek SI, je třeba změnit definice čtyř jejích základních jednotek, kilogramu, ampéru, kelvinu a molu. K tomuto témat probíhá intenzivní diskuse, která by měla vyústit v přijetí nových definic v r. 2011. Tento referát seznamuje čtenáře s některými aspekty předložených návrhů a s důsledky nových definic pro praktickou metrologii i pro vědecký výzkum., Pavel Svoboda., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public