scholarly journals Lowering pO2 Interacts with Photoperiod to Alter Physiological Performance of the Coastal Diatom Thalassiosira pseudonana

2021 ◽  
Vol 9 (12) ◽  
pp. 2541
Author(s):  
Bokun Chen ◽  
Jihua Liu ◽  
Ge Xu ◽  
Gang Li
Keyword(s):  
Optimal Growth ◽  
Thalassiosira Pseudonana ◽  
Photosynthetic Oxygen Evolution ◽  
Transcriptome Data ◽  
Sod Activity ◽  
Chl A ◽  
Negative Effect ◽  
Mda Content ◽  
Photosynthetic Oxygen ◽  
Photochemical Quantum Yield

Exacerbating deoxygenation is extensively affecting marine organisms, with no exception for phytoplankton. To probe these effects, we comparably explored the growth, cell compositions, photosynthesis, and transcriptome of a diatom Thalassiosira pseudonana under a matrix of pO2 levels and Light:Dark cycles at an optimal growth light. The growth rate (μ) of T. pseudonana under a 8:16 L:D cycle was enhanced by 34% by low pO2 but reduced by 22% by hypoxia. Under a 16:8 L:D cycle, however, the μ decreased with decreasing pO2 level. The cellular Chl a content decreased with decreasing pO2 under a 8:16 L:D cycle, whereas the protein content decreased under a 16:8 L:D cycle. The prolonged photoperiod reduced the Chl a but enhanced the protein contents. The lowered pO2 reduced the maximal PSII photochemical quantum yield (FV/FM), photosynthetic oxygen evolution rate (Pn), and respiration rate (Rd) under the 8:16 or 16:8 L:D cycles. Cellular malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were higher under low pO2 than ambient pO2 or hypoxia. Moreover, the prolonged photoperiod reduced the FV/FM and Pn among all three pO2 levels but enhanced the Rd, MDA, and SOD activity. Transcriptome data showed that most of 26 differentially expressed genes (DEGs) that mainly relate to photosynthesis, respiration, and metabolism were down-regulated by hypoxia, with varying expression degrees between the 8:16 and 16:8 L:D cycles. In addition, our results demonstrated that the positive or negative effect of lowering pO2 upon the growth of diatoms depends on the pO2 level and is mediated by the photoperiod.

Changes in the Growth, Physiology and Biochemistry of Alexandrium tamarense under Ulva pertusa Kjellman Stress and UV-B Radiation

2012 ◽  
Vol 610-613 ◽  
pp. 3231-3235
Author(s):  
Heng Jiang Cai ◽  
Chang Fa Liu ◽  
Hai Feng Wei
Keyword(s):  
Radiation Treatment ◽  
Ulva Pertusa ◽  
Alexandrium Tamarense ◽  
Combined Effects ◽  
Sod Activity ◽  
Chl A ◽  
Growth Physiology ◽  
Physiology And Biochemistry ◽  
Mda Content ◽  
Physiological And Biochemical

Effects of Ulva pertusa Kjellman stress and UV-B radiation on the growth, physiology and biochemistry of Alexandrium tamarense were studied under laboratory conditions. The results demonstrated that U. pertusa stress and UV-B radiation could inhibit the growth of A. tamarense. Physiology and biochemistry of A. tamarense could be affected under U. pertusa stress and UV-B radiation treatment. U. pertusa stress caused the increase in SOD activity and decrease in H2O2 content. As for UV-B radiation, Chl-a content and soluble content were decreased, while H2O2 content, MDA content and SOD activity were increased. With regard to the combined effects of U. pertusa stress and UV-B radiation, Chl-a content and soluble content were decreased, while MDA content and SOD activity were increased. Compared with UV-B radiation, the combined effects of U. pertusa stress and UV-B radiation treatment on the growth, physiological and biochemical were indiscernible.

Effects of UV-B Radiation on the Growth, Physiological and Biochemical Characteristics of Chondrus ocellatus Holm (Rhodophyta)

2014 ◽  
Vol 955-959 ◽  
pp. 222-226
Author(s):  
Heng Jiang Cai ◽  
Zhi Hua Zhang ◽  
Chang Fa Liu ◽  
Hai Feng Wei ◽  
Jun Xin Zhang
Keyword(s):  
Growth Inhibition ◽  
Soluble Proteins ◽  
Ultraviolet B ◽  
Sod Activity ◽  
Biochemical Characteristics ◽  
Chl A ◽  
Physiological And Biochemical Characteristics ◽  
Chondrus Ocellatus ◽  
Mda Content ◽  
Physiological And Biochemical

Effects of enhanced ultraviolet B (UV-B, 280-320 nm) on macroalgae have gained particular attention in recent years. We investigated the changes in the growth, physiological and biochemical characteristics of C. ocellatus under UV-B radiation in this study. The results showed that UV-B could inhibit the growth of C. ocellatus (p<0.01) and the growth inhibition was more significant with increased doses of UV-B radiation. The effects of UV-B radiation on Chl-a content in C. ocellatus were not obvious. The soluble proteins content and MDA content in C. ocellatus were increased by UV-B radiation, and the increase of MDA content was extraordinary significant. The SOD activity and CAT activity were increased when the intensity of UV-B radiation was 7.2 J/m2, while the SOD activity and CAT activity were decreased when the intensity of UV-B radiation was 21.6 J/m2.

Evaluation of Azadirachtin on Arthrospira plantensis Gomont growth parameters and antioxidant enzymes

2020 ◽  
Vol 56 ◽  
pp. 8
Author(s):  
Hatice Tunca ◽  
Ali Doğru ◽  
Feray Köçkar ◽  
Burçin Önem ◽  
Tuğba Ongun Sevindik
Keyword(s):  
Enzyme Activity ◽  
Growth Parameters ◽  
Arthrospira Platensis ◽  
Proline Content ◽  
Enzyme Analysis ◽  
Free Proline ◽  
Sod Activity ◽  
Pesticide Pollution ◽  
Antioxidant Parameters ◽  
Mda Content

Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-a amount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza on Arthrospira platensis Gomont. Aza was applied between 0–20 μg mL−1 concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-a content in A. platensis cultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1 concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1 concentrations. The H2O2 content significantly increased at 12, 16 and 20 μg mL−1 concentrations (p < 0.05) while the free proline content decreased at 4 μg mL−1 concentration (p < 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.

Protective Effects of Ginsenosides on 17α-Ethynyelstradiol-Induced Intrahepatic Cholestasis via Anti-Oxidative and Anti-Inflammatory Mechanisms in Rats

2017 ◽  
Vol 45 (08) ◽  
pp. 1613-1629 ◽  
Author(s):  
Yan-Jiao Xu ◽  
Zao-Qin Yu ◽  
Cheng-Liang Zhang ◽  
Xi-Ping Li ◽  
Cheng-Yang Feng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alkaline Phosphatase ◽  
Superoxide Dismutase ◽  
Protein Expression ◽  
Intrahepatic Cholestasis ◽  
Serum Levels ◽  
Total Bile Acid ◽  
Protective Effects ◽  
Sod Activity ◽  
Mda Content

The present study was designed to assess the effects and potential mechanisms of ginsenosides on 17[Formula: see text]-ethynyelstradiol (EE)-induced intrahepatic cholestasis (IC). Ginsenoside at doses of 30, 100, 300[Formula: see text]mg/kg body weight was intragastrically (i.g.) given to rats for 5 days to examine the effect on EE-induced IC. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bile acid (TBA) were measured. Hepatic malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined. Protein expression of proinflammatory cytokines TNF-[Formula: see text], IL-6 and IL-1[Formula: see text] was analyzed by immunohistochemistry and Western blot. Results indicated that ginsenosides remarkably prevented EE-induced increase in the serum levels of AST, ALT, ALP and TBA. Moreover, the elevation of hepatic MDA content induced by EE was significantly reduced, while hepatic SOD activities were significantly increased when treated with ginsenosides. Histopathology of the liver tissue showed that pathological injuries were relieved after treatment with ginsenosides. In addition, treatment with ginsenosides could significantly downregulate the protein expression of TNF-[Formula: see text], IL-6 and IL-1[Formula: see text] compared with EE group. These findings indicate that ginsenosides exert the hepatoprotective effect on EE-induced intrahepatic cholestasis in rats, and this protection might be attributed to the attenuation of oxidative stress and inflammation.

scholarly journals TIP family aquaporins play role in chloroplast osmoregulation and photosynthesis

2020 ◽  
Author(s):  
Azeez Beebo ◽  
Ahmad Zia ◽  
Christopher R. Kinzel ◽  
Andrei Herdean ◽  
Karim Bouhidel ◽  
...  
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Electron Transport ◽  
Chloroplast Envelope ◽  
Photosynthetic Oxygen Evolution ◽  
Wild Type ◽  
Thylakoid Lumen ◽  
Photosynthetic Oxygen ◽  
Osmotic Treatment ◽  
Envelope Membranes

SUMMARYPhotosynthetic oxygen evolution by photosystem II requires water supply into the chloroplast to reach the thylakoid lumen. A rapid water flow is also required into the chloroplast for optimal oxygen evolution and to overcome osmotic stress. The mechanisms governing water transport in chloroplasts are largely unexplored. Previous proteomics indicated the presence of three aquaporins from the tonoplast intrinsic protein (TIP) family, TIP1;1, TIP1;2 and TIP2;1, in chloroplast membranes of Arabidopsis thaliana. Here we revisited their location and studied their role in chloroplasts. Localization experiments indicated that TIP2;1 resides in the thylakoid, whereas TIP1;2 is present in both thylakoid and envelope membranes. Mutants lacking TIP1;2 and/or TIP2;1 did not display a macroscopic phenotype when grown under standard conditions. The mutant chloroplasts and thylakoids underwent less volume changes than the corresponding wild type preparations upon osmotic treatment and in the light. Significantly reduced rates of photosynthetic electron transport were obtained in the mutant leaves, with implications on the CO2 fixation rates. However, electron transport rates did not significantly differ between mutants and wild type when isolated thylakoids were examined. Less acidification of the thylakoid lumen was measured in mutants thylakoids, resulting in a slower induction of delta pH-dependent photoprotective mechanisms. These results identify TIP1;2 and TIP2;1 as chloroplast proteins and highlight their importance for osmoregulation and optimal photosynthesis. A third aquaporin, TIP1;1, is present in the chloroplast envelope, and may play role in photosynthesis under excessive light conditions, as based on the weak photosynthetic phenotype of its mutant.

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