scholarly journals Coral Forests: How Mangroves Provide Refuge to Corals from Light Stress on the Shallow Reef

2021 ◽  
Vol 102 (3) ◽  
Author(s):  
Heather A. Stewart ◽  
David I. Kline ◽  
Lauren J. Chapman ◽  
Andrew H. Altieri
Keyword(s):  
Light Stress ◽  
Shallow Reef

scholarly journals 3PC-065 Impact of light stress on the isoform profile of nivolumab (Opdivo) in opened vials estimated by (RP)UHPLC-UV-(HESI/Orbitrap)-MS

2021 ◽  
Author(s):  
A Torrente-López ◽  
J Hermosilla-Fernández ◽  
J Hernández-Jiménez ◽  
J Cabeza ◽  
A Salmerón-García ◽  
...  
Keyword(s):  
Light Stress ◽  
Orbitrap Ms

scholarly journals Gradual Response of Cyanobacterial Thylakoids to Acute High-Light Stress—Importance of Carotenoid Accumulation

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1916
Author(s):  
Myriam Canonico ◽  
Grzegorz Konert ◽  
Aurélie Crepin ◽  
Barbora Šedivá ◽  
Radek Kaňa
Keyword(s):  
Single Cell ◽  
Thylakoid Membrane ◽  
Intermediate Phase ◽  
Light Stress ◽  
Fast Response ◽  
High Light ◽  
Photochemical Quenching ◽  
Second Phase ◽  
Ros Scavenging ◽  
Non Photochemical Quenching

Light plays an essential role in photosynthesis; however, its excess can cause damage to cellular components. Photosynthetic organisms thus developed a set of photoprotective mechanisms (e.g., non-photochemical quenching, photoinhibition) that can be studied by a classic biochemical and biophysical methods in cell suspension. Here, we combined these bulk methods with single-cell identification of microdomains in thylakoid membrane during high-light (HL) stress. We used Synechocystis sp. PCC 6803 cells with YFP tagged photosystem I. The single-cell data pointed to a three-phase response of cells to acute HL stress. We defined: (1) fast response phase (0–30 min), (2) intermediate phase (30–120 min), and (3) slow acclimation phase (120–360 min). During the first phase, cyanobacterial cells activated photoprotective mechanisms such as photoinhibition and non-photochemical quenching. Later on (during the second phase), we temporarily observed functional decoupling of phycobilisomes and sustained monomerization of photosystem II dimer. Simultaneously, cells also initiated accumulation of carotenoids, especially ɣ–carotene, the main precursor of all carotenoids. In the last phase, in addition to ɣ-carotene, we also observed accumulation of myxoxanthophyll and more even spatial distribution of photosystems and phycobilisomes between microdomains. We suggest that the overall carotenoid increase during HL stress could be involved either in the direct photoprotection (e.g., in ROS scavenging) and/or could play an additional role in maintaining optimal distribution of photosystems in thylakoid membrane to attain efficient photoprotection.

scholarly journals Effects of Modification of Light Parameters on the Production of Cryptophycin, Cyanotoxin with Potent Anticancer Activity, in Nostoc sp.

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 809
Author(s):  
Alexandros Polyzois ◽  
Diana Kirilovsky ◽  
Thi-hanh Dufat ◽  
Sylvie Michel
Keyword(s):  
Light Stress ◽  
Red Light ◽  
Major Effect ◽  
High Light Intensity ◽  
Efficient Production ◽  
Lower Growth ◽  
Noticeable Increase ◽  
Lower Growth Rate ◽  
Industrial Use ◽  
Effect Of Light

Cryptophycin-1 is a cyanotoxin produced by filamentous cyanobacteria. It has been evaluated as an anticancer agent with great potential. However, its synthesis provides insufficient yield for industrial use. An alternative solution for metabolite efficient production is to stress cyanobacteria by modifying the environmental conditions of the culture (Nostoc sp. ATCC 53789). Here, we examined the effects of light photoperiod, wavelength, and intensity. In light photoperiod, photoperiods 24:0 and 16:8 (light:dark) were tested while in wavelength, orange-red light was compared with blue. Medium, high, and very high light intensity experiments were performed to test the effect of light stress. For a 10-day period, growth was measured, metabolite concentration was calculated through HPLC, and the related curves were drawn. The differentiation of light wavelength had a major effect on the culture, as orange-red filter contributed to noticeable increase in both growth and doubled the cyanotoxin concentration in comparison to blue light. Remarkably, constant light provides higher cryptophycin yield, but slightly lower growth rate. Lastly, the microorganism prefers medium light intensities for both growth and metabolite expression. The combination of these optimal conditions would contribute to the further exploitation of cryptophycin.

scholarly journals Compensation Mechanism of the Photosynthetic Apparatus in Arabidopsis thaliana ch1 Mutants

2020 ◽  
Vol 22 (1) ◽  
pp. 221
Author(s):  
Joanna Wójtowicz ◽  
Adam K. Jagielski ◽  
Agnieszka Mostowska ◽  
Katarzyna B. Gieczewska
Keyword(s):  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Protein Composition ◽  
Mrna Levels ◽  
Chlorophyll B ◽  
Low Light ◽  
Plant Acclimation ◽  
Chlorophyll B Deficiency ◽  
Composition Changes

The origin of chlorophyll b deficiency is a mutation (ch1) in chlorophyllide a oxygenase (CAO), the enzyme responsible for Chl b synthesis. Regulation of Chl b synthesis is essential for understanding the mechanism of plant acclimation to various conditions. Therefore, the main aim of this study was to find the strategy in plants for compensation of low chlorophyll content by characterizing and comparing the performance and spectral properties of the photosynthetic apparatus related to the lipid and protein composition in four selected Arabidopsis ch1 mutants and two Arabidopsis ecotypes. Mutation in different loci of the CAO gene, viz., NW41, ch1.1, ch1.2 and ch1.3, manifested itself in a distinct chlorina phenotype, pigment and photosynthetic protein composition. Changes in the CAO mRNA levels and chlorophyllide a (Chlide a) content in ecotypes and ch1 mutants indicated their significant role in the adjustment mechanism of the photosynthetic apparatus to low-light conditions. Exposure of mutants with a lower chlorophyll b content to short-term (1LL) and long-term low-light stress (10LL) enabled showing a shift in the structure of the PSI and PSII complexes via spectral analysis and the thylakoid composition studies. We demonstrated that both ecotypes, Col-1 and Ler-0, reacted to high-light (HL) conditions in a way remarkably resembling the response of ch1 mutants to normal (NL) conditions. We also presented possible ways of regulating the conversion of chlorophyll a to b depending on the type of light stress conditions.

scholarly journals Salinity Tolerance of Four Hardy Ferns from the Genus Dryopteris Adans. Grown under Different Light Conditions

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Piotr Salachna ◽  
Rafał Piechocki
Keyword(s):  
Light Stress ◽  
Leaf Damage ◽  
Light Conditions ◽  
Reduced Height ◽  
Individual Taxon ◽  
Necrotic Spots ◽  
Sun And Shade ◽  
Tolerance To Salinity ◽  
Leaf Greenness ◽  
Ground Part

Hardy ferns form a group of attractive garden perennials with an unknown response to abiotic stresses. The aim of this study was to evaluate the tolerance of three species of ferns of Dryopteris genus (D. affinis, D. atrata and D. filix-mas) and one cultivar (D. filix-mas cv. “Linearis-Polydactylon”) to salinity and light stress. The plants were grown in full sun and shade and watered with 50 and 100 mM dm−3 NaCl solution. All taxa treated with 100 mM NaCl responded with reduced height, leaf greenness index and fresh weight of the above-ground part. In D. affinis and D. atrata salinity caused leaf damage manifested by necrotic spots, which was not observed in the other two taxa. The effect of NaCl depended on light treatments and individual taxon. D. affinis and D. atrata were more tolerant to salinity when growing under shade. Contrary to that, D. filix-mas cv. “Linearis-Polydactylon” seemed to show significantly greater tolerance to this stress under full sun. Salt-treated D. filix-mas cv. “Linearis-Polydactylon” plants accumulated enhanced amounts of K+ in the leaves, which might be associated with the taxon’s tolerance to salinity. Among the investigated genotypes, D. filix-mas cv. “Linearis-Polydactylon” seemed the most and D. affinis and D. atrata the least tolerant to salinity and light stress.

Phosphorylation and nitration levels of photosynthetic proteins are conversely regulated by light stress

2011 ◽  
Vol 77 (4-5) ◽  
pp. 461-473 ◽  
Author(s):  
Dmitry Galetskiy ◽  
Jens N. Lohscheider ◽  
Alexey S. Kononikhin ◽  
Igor A. Popov ◽  
Eugene N. Nikolaev ◽  
...  
Keyword(s):  
Light Stress ◽  
Photosynthetic Proteins
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