Superoxide dismutases (SODs) catalyze the dismutation of superoxide and play an important role in reducing oxidative stress in plants. Based on in-gel SOD activity staining, chloroplasts of the moss Physcomitrella pat...Superoxide dismutases (SODs) catalyze the dismutation of superoxide and play an important role in reducing oxidative stress in plants. Based on in-gel SOD activity staining, chloroplasts of the moss Physcomitrella patens have two CuZn-SODs as the major SOD isozymes and minor SODs, including a Fe-SOD and two Mn-SODs. To investigate the contribution of chloroplastic SODs to stress tolerance in P. patens, we generated a double mutant lacking chloroplastic CuZn-SOD genes. The mutant did not show any differences in comparison to the wild type based on the growth of protonemata on normal and high-salt media, extractable activities of the other SODs after culture on normal and high-salt media, and inhibition of Fv/Fm under stress conditions (high-salt, high-light, and high-temperature). These results indicate that chloroplastic CuZn-SODs do not play a principal role in oxidative stress tolerance in chloroplasts under the investigated conditions. These findings explain the previously reported unusual response of P. patens to copper deficiency, in which chloroplastic CuZn-SODs are preferentially inactivated but cytosolic CuZn-SODs are unaffected.展开更多
The established culture of gametophytes of the red alga Pyropia yezoensis (TU-1) is superficially colonized by epiphytic bacteria. By 16S rRNA sequencing, 6 bacterial species were identified, and a culturable bacteriu...The established culture of gametophytes of the red alga Pyropia yezoensis (TU-1) is superficially colonized by epiphytic bacteria. By 16S rRNA sequencing, 6 bacterial species were identified, and a culturable bacterium, Neptunomonas sp. BPy-1, was isolated. The 16S rRNA sequences of BPy-1 showed 100% identity with that of Neptunomonas sp. 0536, a probiotic bacterium found in greenshell mussels in New Zealand. Physiological tests revealed that 22 characters were identical between BPy-1 and 0536, but that 4 characters differed. BPy-1 cannot grow in the artificial seawater used for the culture of gametophytes. BPy-1 can grow in the artificial seawater with ethanol or butanol but not in methanol or propanol. To determine the effect of BPy-1 on gametophyte growth, BPy-1 colonization was reduced by 80% using a multi-enzyme cleaner. Changing the cleaner concentration yielded two types of gametophytes, a compressed or callus-like form and a nearly normal form. BPy-1 promoted the growth of the treated gametophytes with relatively normal form, while it showed less effect on compressed gametophytes. These findings suggested that BPy-1 promotes the growth of damaged gametophytes but does not affect the development of normal gametophytes.展开更多
文摘Superoxide dismutases (SODs) catalyze the dismutation of superoxide and play an important role in reducing oxidative stress in plants. Based on in-gel SOD activity staining, chloroplasts of the moss Physcomitrella patens have two CuZn-SODs as the major SOD isozymes and minor SODs, including a Fe-SOD and two Mn-SODs. To investigate the contribution of chloroplastic SODs to stress tolerance in P. patens, we generated a double mutant lacking chloroplastic CuZn-SOD genes. The mutant did not show any differences in comparison to the wild type based on the growth of protonemata on normal and high-salt media, extractable activities of the other SODs after culture on normal and high-salt media, and inhibition of Fv/Fm under stress conditions (high-salt, high-light, and high-temperature). These results indicate that chloroplastic CuZn-SODs do not play a principal role in oxidative stress tolerance in chloroplasts under the investigated conditions. These findings explain the previously reported unusual response of P. patens to copper deficiency, in which chloroplastic CuZn-SODs are preferentially inactivated but cytosolic CuZn-SODs are unaffected.
文摘The established culture of gametophytes of the red alga Pyropia yezoensis (TU-1) is superficially colonized by epiphytic bacteria. By 16S rRNA sequencing, 6 bacterial species were identified, and a culturable bacterium, Neptunomonas sp. BPy-1, was isolated. The 16S rRNA sequences of BPy-1 showed 100% identity with that of Neptunomonas sp. 0536, a probiotic bacterium found in greenshell mussels in New Zealand. Physiological tests revealed that 22 characters were identical between BPy-1 and 0536, but that 4 characters differed. BPy-1 cannot grow in the artificial seawater used for the culture of gametophytes. BPy-1 can grow in the artificial seawater with ethanol or butanol but not in methanol or propanol. To determine the effect of BPy-1 on gametophyte growth, BPy-1 colonization was reduced by 80% using a multi-enzyme cleaner. Changing the cleaner concentration yielded two types of gametophytes, a compressed or callus-like form and a nearly normal form. BPy-1 promoted the growth of the treated gametophytes with relatively normal form, while it showed less effect on compressed gametophytes. These findings suggested that BPy-1 promotes the growth of damaged gametophytes but does not affect the development of normal gametophytes.
