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Coordinated downregulation of the photosynthetic apparatus as a protective mechanism against UV exposure in the diatom Corethron hystrix
摘要： The effect of ultraviolet radiation (UVR) on photosynthetic efficiency and the resulting mechanisms against UV exposure employed by phytoplankton are not completely understood. To address this knowledge gap, we developed a novel close-coupled, wavelength-configurable platform designed to produce precise and repeatable in vitro irradiation of Corethron hystrix, a member of a genera found abundantly in the Southern Ocean where UV exposure is high. We aimed to determine its metabolic, protective, and repair mechanisms as a function of varying levels of specific electromagnetic energy. Our results show that the physiological responses to each energy level of UV have a negative linear decrease in the photosynthetic efficiency of photosystem II proportional to UV intensity, corresponding to a large increase in the turnover time of quinone reoxidation. Gene expression changes of photosystem II-related reaction center proteins D1, CP43, and CP47 showed coordinated downregulation whereas the central metabolic pathway demonstrated mixed expression of up and downregulated transcripts after UVR exposure. These results suggest that while UVR may damage photosynthetic machinery, oxidative damage may limit production of new photosynthetic and electron transport complexes as a result of UVR exposure.
关键词： Transcriptome,Diatom,UVR,Photosynthetic damage
更新于2025-09-23 15:23:52
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Photocarcinogenesis & Photoprotection || Ultraviolet Radiation (UVR): An Introduction
摘要： Radiant energy of sun is essential to perform metabolic processes of all flora and fauna on the earth. The electromagnetic radiations (EMR) emitted by sun extend from very long wavelength radiation, such as radiowaves (A ″′ 3 × 108 m), to very short wavelength radiation, such as cosmic rays (A ″′ 3 × 10?19 m). The EMR reaching at the earth surface contains wavelength from 290 to 4000 nm. However, the UV portion covers from 200 to 400 nm. The range from 200 to 400 nm is often arbitrarily categorized into UVA, UVB, and UVC radiation. Solar radiation less than 290 nm does not reach at the earth’s surface due to the presence of O3 layer in stratospheric zone. But, last from few decades due to anthropogenic activities, the concentration of ozone layer decreases on stratospheric zone. As a consequence of that, UVB radiation levels are rising to 1% a year. Thus, the deleterious health effects on human beings (skin aging, cataracts, skin cancer, and immune suppression) are enhanced by UVR.
关键词： Skin cancer,Ozone,UVR,Skin aging,EMR
更新于2025-09-09 09:28:46