Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
Author(s):  
Aloysius Wild ◽  
Matthias Höpfner ◽  
Wolfgang Rühle ◽  
Michael Richter
Keyword(s):  
Photosystem Ii ◽  
Functional Organization ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Molar Ratio ◽  
Light Conditions ◽  
Low Light ◽  
Pigment System ◽  
Transport Chain ◽  
The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

scholarly journals Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

2017 ◽  
Vol 14 (24) ◽  
pp. 5693-5704 ◽  
Author(s):  
Gabriella M. Weiss ◽  
Eva Y. Pfannerstill ◽  
Stefan Schouten ◽  
Jaap S. Sinninghe Damsté ◽  
Marcel T. J. van der Meer
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Emiliania Huxleyi ◽  
High Light Intensity ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Long Chain

Abstract. Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

scholarly journals Hybrid tea-roses under controlled light conditions. 2. Flowering of seedlings as dependent on the level of irradiance.

1978 ◽  
Vol 26 (1) ◽  
pp. 128-132
Author(s):  
D.P. de Vries ◽  
L. Smeets
Keyword(s):  
Selection Procedure ◽  
Light Conditions ◽  
Low Light ◽  
Light Requirement ◽  
Experimental Conditions ◽  
Light Intensities

Under the experimental conditions described in the preceding abstract, mortality increased with decreasing light intensities. The percentage of flowering seedlings increased and that of aborting ones decreased with irradiance. For the populations studied, no genotype-environment interactions for the percentages of flowering seedlings occurred. A selection procedure for roses with a low light requirement for flowering is considered. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Light intensity regulates phototaxis, foraging and righting behaviors of the sea urchin Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8001 ◽  
Author(s):  
Jiangnan Sun ◽  
Xiaomei Chi ◽  
Mingfang Yang ◽  
Jingyun Ding ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Foraging Behavior ◽  
Sea Urchins ◽  
High Light Intensity ◽  
High Light ◽  
Strongylocentrotus Intermedius ◽  
Low Light ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Significant Difference

Small sea urchins Strongylocentrotus intermedius (1–2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24–209 lx) and high light intensity (252–2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69–209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252–690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

Stomatal aperture can compensate altered stomatal density in Arabidopsis thaliana at growth light conditions

2006 ◽  
Vol 33 (11) ◽  
pp. 1037 ◽  
Author(s):  
Dirk Büssis ◽  
Uritza von Groll ◽  
Joachim Fisahn ◽  
Thomas Altmann
Keyword(s):  
Arabidopsis Thaliana ◽  
Stomatal Conductance ◽  
Stomatal Density ◽  
Co2 Assimilation ◽  
High Light ◽  
Stomatal Aperture ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Wild Type ◽  
Light Intensities

Stomatal density of transgenic Arabidopsis thaliana plants over-expressing the SDD1 (stomatal density and distribution) gene was reduced to 40% and in the sdd1-1 mutant increased to 300% of the wild type. CO2 assimilation rate and stomatal conductance of over-expressers and the sdd1-1 mutant were unchanged compared with wild types when measured under the light conditions the plants were exposed to during growth. Lower stomatal density was compensated for by increased stomatal aperture and conversely, increased stomatal density was compensated for by reduced stomatal aperture. At high light intensities the assimilation rates and stomatal conductance of SDD1 over-expressers were reduced to 80% of those in wild type plants. Areas beneath stomata and patches lacking stomata were analysed separately. In areas without stomata, maximum fluorescence yield (Fv / Fm) and quantum yield of photosystem II (Φ PSII) were significantly lower than in areas beneath stomata. In areas beneath stomata, Fv / Fm and Φ PSII were identical to levels measured in wild type leaves. At high light intensities over-expressers showed decreased photochemical quenching (qP) compared with wild types. However, the decrease of qP was significantly stronger in areas without stomata than in mesophyll areas beneath stomata. At high CO2 partial pressures and high light intensities CO2 assimilation rates of SDD1 over-expressers did not reach wild type levels. These results indicate that photosynthesis in SDD1 over-expressers was reduced because of limiting CO2 in areas furthest from stomata at high light.

scholarly journals Transcriptome analysis of genes and pathways associated with metabolism in Scylla paramamosain under different light intensities during indoor overwintering

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Li ◽  
Junming Zhou ◽  
Huan Wang ◽  
Changkao Mu ◽  
Ce Shi ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Light Intensity ◽  
Differentially Expressed Genes ◽  
High Light ◽  
Differentially Expressed ◽  
Scylla Paramamosain ◽  
Strong Impact ◽  
Low Light ◽  
Light Intensities ◽  
Light Group

Abstract Background Scylla paramamosain is one of the commercially crucial marine crustaceans belonging to the genus Scylla, which is commonly distributed along the coasts of China, Vietnam, and Japan. Genomic and transcriptomic data are scarce for the mud crab. Light intensity is one of the ecological factors that affect S. paramamosain during indoor overwintering. To understand the energy metabolism mechanism adapted to light intensity, we analyzed the transcriptome of S. paramamosain hepatopancreas in response to different light intensities (0, 1.43, 40.31 μmol·m− 2·s− 1). Results A total of 5052 differentially expressed genes were identified in low light group (LL group, 3104 genes were up-regulated and 1948 genes were down-regulated). A total of 7403 differentially expressed genes were identified in high light group (HL group, 5262 genes were up-regulated and 2141 genes were down-regulated). S. paramamosain adapts to different light intensity environments through the regulation of amino acids, fatty acids, carbon and energy metabolism. Different light intensities had a strong impact on the energy generation of S. paramamosain by influencing oxygen consumption rate, aerobic respiration, glycolysis/gluconeogenesis pathway, the citrate cycle (TCA cycle) and fatty acid degradation. Conclusion Low light is more conducive to the survival of S. paramamosain, which needs to produce and consume relatively less energy to sustain physiological activities. In contrast, S. paramamosain produced more energy to adapt to the pressure of high light intensities. The findings of the study add to the knowledge of regulatory mechanisms related to S. paramamosain metabolism under different light intensities.

scholarly journals The Response Regulator RpaB Binds to the Upstream Element of Photosystem I Genes To Work for Positive Regulation under Low-Light Conditions in Synechocystis sp. Strain PCC 6803

2008 ◽  
Vol 191 (5) ◽  
pp. 1581-1586 ◽  
Author(s):  
Yurie Seino ◽  
Tomoko Takahashi ◽  
Yukako Hihara
Keyword(s):  
Photosystem I ◽  
Promoter Activity ◽  
Response Regulator ◽  
Core Promoter ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Positive Regulation ◽  
Upstream Element ◽  
Pcc 6803

ABSTRACT The coordinated high-light response of genes encoding subunits of photosystem I (PSI) is achieved by the AT-rich region located just upstream of the core promoter in Synechocystis sp. strain PCC 6803. The upstream element enhances the basal promoter activity under low-light conditions, whereas this positive regulation is lost immediately after the shift to high-light conditions. In this study, we focused on a high-light regulatory 1 (HLR1) sequence included in the upstream element of every PSI gene examined. A gel mobility shift assay revealed that a response regulator RpaB binds to the HLR1 sequence in PSI promoters. Base substitution in the HLR1 sequence or decrease in copy number of the rpaB gene resulted in decrease in the promoter activity of PSI genes under low-light conditions. These observations suggest that RpaB acts as a transcriptional activator for PSI genes. It is likely that RpaB binds to the HLR1 sequence under low-light conditions and works for positive regulation of PSI genes and for negative regulation of high-light-inducible genes depending on the location of the HLR1 sequence within target promoters.

scholarly journals Coordinated High-Light Response of Genes Encoding Subunits of Photosystem I Is Achieved by AT-Rich Upstream Sequences in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2007 ◽  
Vol 189 (7) ◽  
pp. 2750-2758 ◽  
Author(s):  
Masayuki Muramatsu ◽  
Yukako Hihara
Keyword(s):  
Photosystem I ◽  
Promoter Region ◽  
Promoter Activity ◽  
Light Response ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Genes Encoding ◽  
Responsive Element ◽  
Pcc 6803

ABSTRACT Genes encoding subunits of photosystem I (PSI genes) in the cyanobacterium Synechocystis sp. strain PCC 6803 are actively transcribed under low-light conditions, whereas their transcription is coordinately and rapidly down-regulated upon the shift to high-light conditions. In order to identify the molecular mechanism of the coordinated high-light response, we searched for common light-responsive elements in the promoter region of PSI genes. First, the precise architecture of the psaD promoter was determined and compared with the previously identified structure of the psaAB promoter. One of two promoters of the psaAB genes (P1) and of the psaD gene (P2) possessed an AT-rich light-responsive element located just upstream of the basal promoter region. These sequences enhanced the basal promoter activity under low-light conditions, and their activity was transiently suppressed upon the shift to high-light conditions. Subsequent analysis of psaC, psaE, psaK1, and psaLI promoters revealed that their light response was also achieved by AT-rich sequences located at the −70 to −46 region. These results clearly show that AT-rich upstream elements are responsible for the coordinated high-light response of PSI genes dispersed throughout Synechocystis genome.

scholarly journals Quantitative Ecological Impact Assessments using  Natural Abundance Carbon and Nitrogen Stable Isotope Signatures

2021 ◽  
Author(s):  
◽  
Bruce David Dudley
Keyword(s):  
Stable Isotope ◽  
Nitrogen Isotope ◽  
High Light ◽  
Rocky Reef ◽  
Sewage Effluent ◽  
Light Conditions ◽  
Nitrogen Stable Isotope ◽  
Low Light ◽  
Carbon And Nitrogen ◽  
Reef Community

<p>The use of delta15N and delta13C signatures to infer sources of enrichment in ecological systems relies on predictability in the transfer of delta15N and delta13C ratios. This thesis examines patterns of delta15N and delta13C change as pools of nitrogen and carbon move from a sewage effluent discharge into organisms in an adjacent coastal rocky reef community (Titahi Bay, New Zealand). These changes and their mechanisms are examined in the broader context of current research using carbon and nitrogen stable isotope ratios in marine ecology, with particular reference to impact assessment. Firstly this thesis examines the assimilation of nitrogen and carbon isotopes in Ulva sp. under varying light conditions and nitrogen source (e.g., nitrate or ammonium). In a field study, algae grown at depth and under lower light conditions showed comparatively lighter nitrogen isotope signatures relative to the predicted concentration of available 15N-enriched sewage nitrogen. In a complementary laboratory experiment, results from manipulated light availability and N source (either nitrate or ammonium, in equivalent molar concentrations) suggest that: 1) low-light conditions can produce algae with lighter nitrogen isotope signatures; and 2) this effect was more pronounced for ammonium (3.7 per mil difference between high light and low light treatments) than for nitrate (0.6 per mil difference between high light and low light treatments) sources. Stable carbon isotope ratios (delta13C) of Ulva sp.grown in conditions of low nitrogen availability were shown to be generally lower than those grown in nitrogen rich conditions in both field and laboratory studies. Where nitrogen supply was sufficient for growth, low light conditions also produced generally lower delta13C signatures than high light conditions. Experimental trials with a uniform dissolved inorganic carbon source and altered light and nitrogen enrichment levels produced delta 13C levels in Ulva sp. tissue that spanned the recorded delta13C ranges of many common algal species; -5.99 per mil (high light, with added ammonium and phosphate) to -17.61 per mil (high light without nutrient additions). Chapter 3 of this study examines the growth response of Ulva sp. to surplus nitrate and ammonium (the two most common forms of nitrogen available to plants in seawater), under light limited conditions. Ulva sp. experienced a temporary reduction in growth rate and nitrogen assimilation capacity (shown in tissue nitrogen indices) when grown on nitrate, relative to ammonium. The magnitude and the temporary nature of these results suggest that in natural populations the relative proportion of nitrate or ammonium available is unlikely to significantly affect the growth capacity of Ulva sp. In chapter 4, I use delta13C and delta15N signatures to separately trace the dissolved and particulate fractions of sewage effluent dispersal onto a rocky reef community. Delta15N signatures from tissue of the macroalga Carpophyllum maschalocarpum, and the herbivorous isopod Amphoroidea media tracked the distribution and signature of DIN from a sewage treatment plant that generated heavy delta15N signatures. Delta13C signatures from tissue of the filter-feeding half-crab Petrolisthes elongatus tracked the distribution and signature of suspended sewage particulate organic matter.</p>

scholarly journals Low Light Availability Reduces the Subsurface Sediment Carbon Content in Halophila beccarii From the South China Sea

2021 ◽  
Vol 12 ◽  
Author(s):  
Chanaka Premarathne ◽  
Zhijian Jiang ◽  
Jialu He ◽  
Yang Fang ◽  
Qiming Chen ◽  
...  
Keyword(s):  
Carbon Content ◽  
Light Availability ◽  
Seagrass Beds ◽  
Biomass Carbon ◽  
Light Conditions ◽  
Above Ground Biomass ◽  
Low Light ◽  
Subsurface Sediment ◽  
Light Intensities ◽  
Sediment Carbon

Eutrophication, dredging, agricultural and urban runoffs, and epiphyte overgrowth could reduce light availability for seagrass. This may affect “blue carbon” stocks in seagrass beds. However, little research is available on the effect of light intensities on carbon sequestration capacity in seagrass beds, especially small-bodied seagrasses. The dominant seagrass Halophila beccarii, a vulnerable species on the IUCN Red List, was cultured in different light intensities to examine the response of vegetation and sediment carbon in seagrass beds. The results showed that low light significantly reduced leaf length and above-ground biomass, while carbon content in both above-ground and below-ground tissues were not affected. Low light reduced both the above-ground biomass carbon and the total biomass carbon. Interestingly, while under saturating light conditions, the subsurface and surface carbon content was similar, under low light conditions, subsurface sediment carbon was significantly lower than the surface content. The reduction of subsurface sediment carbon might be caused by less release flux of dissolved organic carbon from roots in low light. Taken together, these results indicate that reduced light intensities, to which these meadows are exposed to, will reduce carbon sequestration capacity in seagrass beds. Measures should be taken to eliminate the input of nutrients on seagrass meadows and dredging activities to maintain the “blue carbon” storage service by enhancing light penetration into seagrass.

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