Organelle

Organelle beta-catenin pathway genomes (cpDNA and mtDNA) were found to be maternally inherited in the interspecific hybridization by molecular analyses of the organelle DNA. In particular, molecular analyses of nuclear DNA revealed that the surviving F1 blades were allodiploids in the haploid gametophytic phase; however, there is a possibility of the occurrence of rapid chromosomal locus elimination and rearrangement in the F1 conchocelis phase.

Our findings are noteworthy to the breeding of cultivated Porphyra and will provide important information for understanding of the speciation of marine plants with high species diversity. “
“Uptake of iodide was studied in the marine microalga Isochrysis sp. (isol. Haines, T.ISO) during short-term incubations with radioactive iodide (125I−). Typical ITF2357 in vivo inhibitors of the sodium/iodide symporter (NIS) did not inhibit iodide uptake, suggesting that iodide is not taken up through this transport protein, as is the case in most vertebrate animals. Oxidation

of iodide was found to be an essential step for its uptake by T.ISO and it seemed likely that hypoiodous acid (HOI) was the form of iodine taken up. Uptake of iodide was inhibited by the addition of thiourea and of other reducing agents, like L-ascorbic acid, L-glutathione and L-cysteine and increased after the addition of oxidized forms of the transition metals Fe and Mn. The simultaneous addition of both hydrogen peroxide (H2O2) and a known iodide-oxidizing myeloperoxidase (MPO) significantly increased iodine uptake, but the addition of H2O2 or MPO separately, had no effect on uptake. This confirms the observation that iodide is oxidized prior to uptake, but it

puts into doubt the involvement of H2O2 excretion and membrane-bound or extracellular haloperoxidase activity of T.ISO. The increase of iodide uptake by T.ISO upon Fe(III) addition suggests the nonenzymatic oxidation of iodide by Fe(III) in a redox reaction and subsequent influx of HOI. This is the first report on the mechanism of iodide uptake in a marine microalga. Thymidylate synthase
“The diatom Cyclotella meneghiniana Kütz. (SAG 1020-a) was cultured under high-light (HL) and low-light (LL) conditions with either high (12 μM) or low (1 μM) iron in the media. Changes in cell morphology, especially cell volume and chloroplast size, were observed in cells grown under low iron. In contrast, HL had a much stronger influence on the photosynthetic apparatus. PSII function was unimpaired under lowered iron supply, but its quantum efficiency and reoxidation rate were reduced under HL conditions. As reported before, HL induced changes in antenna polypeptide composition. Especially the amount of Fcp6, an antenna protein related to LI818 and known to be involved in photoprotection, was increased under HL but was significantly reduced under lowered iron.

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