This study describes the relationships between dinitrogen (N2 ) fixation, dihydrogen (H2 ) production, and electron transport associated with photosynthesis and respiration in the marine cyanobacterium Trichodesmium erythraeum Ehrenb. strain IMS101. The ratio of H2 produced:N2 fixed (H2 :N2 ) was controlled by the light intensity and by the light spectral composition and was affected by the gro...

DNA microarray technology was applied to gain insight into the role of the redox state of PQ pool as a retrograde factor mediating differential expression of Arabidopsis nuclear genes during the acclimation to changing irradiance. DNA microarray chips containing probes corresponding to 24 000 Arabidopsis nuclear genes were screened with cRNA samples prepared from leaves of plants exposed for 5 ...

DNA microarray technology was applied to gain insight into the role of the redox state of PQ pool as a retrograde factor mediating differential expression of Arabidopsis nuclear genes during the acclimation to changing irradiance. DNA microarray chips containing probes corresponding to 24,000 Arabidopsis nuclear genes were screened with cRNA samples prepared from leaves of plants exposed for 5 ...

Cryptomonads show strong seasonal distribution in lakes yet little is known of their nutrient requirements. In this study, we examined the role of Fe nutrition in the growth and photosynthetic properties of two freshwater cryptomonads (Cryptomonas sp. UTCC 337 and C. erosa UTCC 446). Cryptomonas sp. appeared more tolerant to Fe deprivation compared with C. erosa. Growth rates calculated for Cry...

Chloroplasts, mitochondria, and peroxisomes from leaves were separated by isopycnic sucrose density gradient centrifugation. The peroxisomes converted glycolate-(14)C or glyoxylate-(14)C to glycine, and contained a glutamate: glyoxylate aminotransferase as indicated by an investigation of substrate specificity. The pH optimum for the aminotransferase was between 7.0 and 7.5, and the Km for l-gl...

Recently, the new technique of electron spin resonance in zero magnetic field, as observed by Microwave Induced changes in Fluorescence (MIF) has been applied to the study of the light-induced triplet state in chloroplasts under reducing conditions [ 1 ] . Two resonances were detected at 723 and 952 MHz. The resonances were observed also in samples in which the acceptor of photosystem 2 was red...

Two Clark-type polarographic electrodes were used to measure simultaneous H(2) and O(2) exchange from three species of the blue-green alga Anabaena. Maximum H(2) photoevolution from N(2)-fixing cultures of Anabaena required only the removal of dissolved O(2) and N(2); no adaptation period was necessary. No correlation of H(2) photoproduction with photosynthetic O(2) evolution, beyond their mutu...

Serious environmental degradation of aquatic ecosystems has been caused by eutrophication and by pollutants such as herbicides. Therefore, measurement of in situ algal photosynthetic activity is important for environmental monitoring. With ordinary nonimaging fluorometers, algal chlorophyll fluorescence can be measured easily, but heterogeneity within samples cannot be detected. Effects of a he...

Prochlorococcus MED4 has, with a total of only 1,716 annotated protein-coding genes, the most compact genome of a free-living photoautotroph. Although light quality and quantity play an important role in regulating the growth rate of this organism in its natural habitat, the majority of known light-sensing proteins are absent from its genome. To explore the potential for light sensing in this p...

Conditions for washed, spinach thylakoid membranes to catalyze cyclic phosphorylation using ferredoxin as the cofactor for electron transfer have been re-examined. It was found necessary to ‘'redox poise” the system; however, the best method to accomplish the poising seemed to be the use of a reductant (glucose-6-phosphate) and not by optimizing the rate of phosphorylation with 3-(3,4-dichlorop...