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 Leaf Senescence of Postproduction Poinsettias in Low-light Stress

1994 ◽  
Vol 119 (5) ◽  
pp. 1006-1013 ◽  
Author(s):  
J. Lorene Embry ◽  
Eugene A. Nothnagel
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Light Harvesting ◽  
Light Stress ◽  
Chlorophyll B ◽  
Excitation Spectra ◽  
Low Light ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra ◽  
Low Light Stress

Photosynthetic light harvesting was investigated under low-light stress conditions relevant to the problem of interior longevity of potted ornamental plants. Comparisons of leaf pigment levels and chlorophyll fluorescence excitation spectra were made for `Gutbier V-10 Amy' poinsettia (Euphorbia pulcherrima Willd.), which has poor interior longevity, and `Eckespoint Lilo' poinsettia, which has superior interior longevity. The results show that `Eckespoint Lilo' had higher total chlorophyll content per leaf area and lower chlorophyll a: chlorophyll b ratio than `Gutbier V-10 Amy'. In low-light stress, `Eckespoint Lilo' retained its chlorophyll or even accumulated higher levels than in high light, while `Gutbier V-10 Amy' did not exhibit higher chlorophyll retention in low light. Both cultivars acclimatized to low-light stress by decreasing the chlorophyll a: chlorophyll b ratio, and this acclimatization was evident sooner in younger, outer-canopy leaves above the pinch than in older leaves below the pinch. Both cultivars also increased the chlorophyll: carotenoid ratio in low light. These changes in pigment composition, which were essentially structural changes, were reflected in functional changes in light harvesting, as assessed by measurements of chlorophyll fluorescence excitation spectra.

Expression analysis of five candidate genes in eight contrasting rice genotypes suggest role of Lagging growth and development 1(LGD1), Pinhead1 (PNH1) and Leaf Panicle 2 (LP2) in low light intensity response at vegetative stage

2020 ◽  
Vol 57 (4) ◽  
pp. 261-270
Author(s):  
Suvendhu S Dutta ◽  
Wricha Tyagi ◽  
Mayank Rai
Keyword(s):  
Light Intensity ◽  
Candidate Genes ◽  
Light Stress ◽  
Vegetative Stage ◽  
Low Light ◽  
Expression Levels ◽  
Low Light Intensity ◽  
Rice Genotypes ◽  
Low Light Stress

Light acts as an energy source in plants for photosynthesis and also is an environmental cue leading to growth and differentiation. The quality and duration of light is therefore, key to obtaining yield and growth targets. Our previous study in rice led to identification of a panel of contrasting genotypes and putative candidate genes and markers for low light intensity tolerance. In the present study, expression of a set of five candidate genes (LGD1, PNH1, ILA1, CAB2R and LP2) previously identified to be associated with low light intensity tolerance was studied in a panel of eight rice genotypes at two time points post stress induction (one hour and two days). Cumulative normalised expression levels for genes LDG1 and PNH1 were down-regulated in response to one hour low light stress only in susceptible genotypes. While the cumulative normalised expression levels of ILA1 and LP2 genes were down- and up-regulated, respectively in tolerant genotypes. After two days of low light stress, expression of PNH1 and LP2 were down- and up-regulated in tolerant and susceptible genotypes, respectively. Our data suggests that genes LGD1, PNH1 and LP2 can be targeted for achieving vegetative stage low light intensity tolerance. Long term stress followed by recovery experiment revealed genotype Pusa Sugangh-5 as tolerant to low light intensity. These experiments suggest that mechanism of low light intensity tolerance in Pusa Sugangh-5 is distinct from the other four tolerant rice genotypes.

scholarly journals Testosterone activates glucose metabolism through AMPK and androgen signaling in cardiomyocyte hypertrophy

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Mayarling Francisca Troncoso ◽  
Mario Pavez ◽  
Carlos Wilson ◽  
Daniel Lagos ◽  
Javier Duran ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Cardiac Hypertrophy ◽  
Glucose Uptake ◽  
Male Rats ◽  
Cardiomyocyte Hypertrophy ◽  
Mrna Levels ◽  
Elevated Glucose ◽  
Amp Activated Protein Kinase ◽  
Cultured Cardiomyocytes

Abstract Background Testosterone regulates nutrient and energy balance to maintain protein synthesis and metabolism in cardiomyocytes, but supraphysiological concentrations induce cardiac hypertrophy. Previously, we determined that testosterone increased glucose uptake—via AMP-activated protein kinase (AMPK)—after acute treatment in cardiomyocytes. However, whether elevated glucose uptake is involved in long-term changes of glucose metabolism or is required during cardiomyocyte growth remained unknown. In this study, we hypothesized that glucose uptake and glycolysis increase in testosterone-treated cardiomyocytes through AMPK and androgen receptor (AR). Methods Cultured cardiomyocytes were stimulated with 100 nM testosterone for 24 h, and hypertrophy was verified by increased cell size and mRNA levels of β-myosin heavy chain (β-mhc). Glucose uptake was assessed by 2-NBDG. Glycolysis and glycolytic capacity were determined by measuring extracellular acidification rate (ECAR). Results Testosterone induced cardiomyocyte hypertrophy that was accompanied by increased glucose uptake, glycolysis enhancement and upregulated mRNA expression of hexokinase 2. In addition, testosterone increased AMPK phosphorylation (Thr172), while inhibition of both AMPK and AR blocked glycolysis and cardiomyocyte hypertrophy induced by testosterone. Moreover, testosterone supplementation in adult male rats by 5 weeks induced cardiac hypertrophy and upregulated β-mhc, Hk2 and Pfk2 mRNA levels. Conclusion These results indicate that testosterone stimulates glucose metabolism by activation of AMPK and AR signaling which are critical to induce cardiomyocyte hypertrophy.

scholarly journals Shading Effects on Leaf Gas Exchange, Leaf Pigments and Secondary Metabolites of Polygonum minus Huds., an Aromatic Medicinal Herb

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 608
Author(s):  
Fairuz Fatini Mohd Yusof ◽  
Jamilah Syafawati Yaacob ◽  
Normaniza Osman ◽  
Mohd Hafiz Ibrahim ◽  
Wan Abd Al Qadr Imad Wan-Mohtar ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Secondary Metabolites ◽  
Chlorophyll A ◽  
Leaf Gas Exchange ◽  
Photosynthesis Rate ◽  
Total Phenolic ◽  
Chlorophyll B ◽  
Low Light ◽  
Total Anthocyanin ◽  
Polygonum Minus

The growing demand for high value aromatic herb Polygonum minus-based products have increased in recent years, for its antioxidant, anticancer, antimicrobial, and anti-inflammatory potentials. Although few reports have indicated the chemical profiles and antioxidative effects of Polygonum minus, no study has been conducted to assess the benefits of micro-environmental manipulation (different shading levels) on the growth, leaf gas exchange and secondary metabolites in Polygonum minus. Therefore, two shading levels (50%:T2 and 70%:T3) and one absolute control (0%:T1) were studied under eight weeks and 16 weeks of exposures on Polygonum minus after two weeks. It was found that P. minus under T2 obtained the highest photosynthesis rate (14.892 µmol CO2 m−2 s−1), followed by T3 = T1. The increase in photosynthesis rate was contributed by the enhancement of the leaf pigments content (chlorophyll a and chlorophyll b). This was shown by the positive significant correlations observed between photosynthesis rate with chlorophyll a (r2 = 0.536; p ≤ 0.05) and chlorophyll b (r2 = 0.540; p ≤ 0.05). As the shading levels and time interval increased, the production of total anthocyanin content (TAC) and antioxidant properties of Ferric Reducing Antioxidant Power (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) also increased. The total phenolic content (TPC) and total flavonoid content (TFC) were also significantly enhanced under T2 and T3. The current study suggested that P.minus induce the production of more leaf pigments and secondary metabolites as their special adaptation mechanism under low light condition. Although the biomass was affected under low light, the purpose of conducting the study to boost the bioactive properties in Polygonum minus has been fulfilled by 50% shading under 16 weeks’ exposure.

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 Altered mRNA Levels of Stress-Related Peptides in Mouse Hippocampus and Caudate-Putamen in Withdrawal after Long-Term Intermittent Exposure to Tobacco Smoke or Electronic Cigarette Vapour

2021 ◽  
Vol 22 (2) ◽  
pp. 599
Author(s):  
Lucia Carboni ◽  
Luisa Ponzoni ◽  
Daniela Braida ◽  
Mariaelvina Sala ◽  
Cecilia Gotti ◽  
...  
Keyword(s):  
Public Health Problem ◽  
Mrna Levels ◽  
Obsessive Compulsive ◽  
Bdnf Mrna ◽  
Object Recognition Test ◽  
Caudate Putamen ◽  
Molecular Alterations ◽  
Marble Burying ◽  
Cigarette Withdrawal

Nicotine addiction is a severe public health problem. The aim of this study was to investigate the alterations in key neurotransmissions after 60 days of withdrawal from seven weeks of intermittent cigarette smoke, e-cigarette vapours, or an e-cigarette vehicle. In the nicotine withdrawal groups, increased depressive and anxiety/obsessive–compulsive-like behaviours were demonstrated in the tail suspension, sucrose preference and marble burying tests. Cognitive impairments were detected in the spatial object recognition test. A significant increase in Corticotropin-releasing factor (Crf) and Crf1 mRNA levels was observed, specifically after cigarette withdrawal in the caudate-putamen nucleus (CPu). The nociceptin precursor levels were reduced by cigarette (80%) and e-cigarette (50%) withdrawal in the CPu. The delta opioid receptor showed a significant reduction in the hippocampus driven by the exposure to an e-cigarette solubilisation vehicle, while the mRNA levels doubled in the CPu of mice that had been exposed to e-cigarettes. Withdrawal after exposure to e-cigarette vapour induced a 35% Bdnf mRNA decrease in the hippocampus, whereas Bdnf was augmented by 118% by cigarette withdrawal in the CPu. This study shows that long-term withdrawal-induced affective and cognitive symptoms associated to lasting molecular alterations in peptidergic signalling may determine the impaired neuroplasticity in the hippocampal and striatal circuitry.

scholarly journals Prenatally traumatized mice reveal hippocampal methylation and expression changes of the stress-related genes Crhr1 and Fkbp5

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anne-Christine Plank ◽  
Stefan Frey ◽  
Lukas Andreas Basedow ◽  
Jalal Solati ◽  
Fabio Canneva ◽  
...  
Keyword(s):  
Stress Reactivity ◽  
Dorsal Hippocampus ◽  
Methylation Status ◽  
Stress Axis ◽  
Mrna Levels ◽  
Fk506 Binding Protein ◽  
Adult Mice ◽  
Stress Related Genes ◽  
Long Term Impact

AbstractIn our previous study, we found that prenatal trauma exposure leads to an anxiety phenotype in mouse pups, characterized by increased corticosterone levels and increased anxiety-like behavior. In order to understand the mechanisms by which aversive in utero experience leads to these long-lasting behavioral and neuroendocrine changes, we investigated stress reactivity of prenatally traumatized (PT) mice, as well as the expression and methylation levels of several key regulatory genes of the stress axis in the dorsal hippocampus (dHPC) of the PT embryo and adult mice. We detected increased corticotropin-releasing hormone receptor 1 (Crhr1) and decreased FK506 binding protein 5 (Fkbp5) mRNA levels in the left dHPC of adult PT mice. These alterations were accompanied by a decreased methylation status of the Crhr1 promoter and an increased methylation status of the Fkbp5 promoter, respectively. Interestingly, the changes in Fkbp5 and Crhr1 mRNA levels were not detected in the embryonic dHPC of PT mice. Together, our findings provide evidence that prenatal trauma has a long-term impact on stress axis function and anxiety phenotype associated with altered Crhr1 and Fkbp5 transcripts and promoter methylation.

scholarly journals The human hepatoma Hep3B cell line as an experimental model in the study of the long-term regulation of acute-phase proteins by cytokines

1992 ◽  
Vol 287 (1) ◽  
pp. 255-259 ◽  
Author(s):  
M Hiron ◽  
M Daveau ◽  
P Arnaud ◽  
J Bauer ◽  
J P Lebreton
Keyword(s):  
Cell Line ◽  
Acute Phase ◽  
Culture System ◽  
Acute Phase Protein ◽  
Hepatoma Cell Line ◽  
Mrna Levels ◽  
Human Hepatoma ◽  
Long Term Culture ◽  
Phase Protein

The regulation of the synthesis by the cytokines interleukin-1 (IL-1) and IL-6 of the positive acute-phase protein alpha 1-acid glycoprotein (AGP) and of the negative acute-phase protein alpha 2-HS glycoprotein (AHSG) has been studied in a long-term culture system of the human hepatoma cell line Hep3B. The culture system contained 30 nM-sodium selenite as the only supplement. This allowed maintenance of the synthesis of the proteins under study at a near steady state for over 3 months. An increase in AGP mRNA and a decrease in AHSG mRNA were observed when cells were treated for two successive 48 h-periods with monocyte-conditioned medium. A return to basal levels was obtained after cessation of the cytokine addition. Two further additions of cytokines led to alterations in mRNA levels similar to those observed following the first cytokine treatment. The amounts of AGP and AHSG secreted were altered in accordance with the mRNA modifications. These results suggest that new cytokine receptors were being constantly synthesized during cell culture. When cytokines were present in the culture medium for 10 days, maximum alterations in AGP and AHSG synthesis were obtained following 2 and 4 days of treatment respectively, but further alterations in protein levels could not be observed afterwards. Expression of IL-6 receptor mRNA was not up-regulated by cytokines, but only by 1 microM-dexamethasone. Our results show that, in this long-term culture system, cytokines induce a response in hepatoma cells similar to that observed in vivo during human inflammatory states. This model could be used to evaluate the effects of agonists or antagonists of cytokines responsible for the hepatic acute-phase protein response.

Stage-specific patterns of collagen gene expression during development of Caenorhabditis elegans

1985 ◽  
Vol 5 (2) ◽  
pp. 363-372
Author(s):  
G N Cox ◽  
D Hirsh
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Composition ◽  
Large Family ◽  
Major Protein ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
C Elegans ◽  
Collagen Protein ◽  
Protein Components ◽  
Collagen Genes

Collagens are the major protein components of the Caenorhabditis elegans cuticle and are encoded by a large family of 40 to 150 closely related but nonidentical genes. We have determined temporal patterns of mRNA accumulation for a large number of collagen genes by screening recombinant phages and plasmids containing cloned collagen genes under high stringency conditions with 32P-labeled cDNA preparations specific for eggs or three postembryonic molts. We find that collagen mRNA levels are regulated both temporally and quantitatively during C. elegans development. Most genes studied exhibit one of four patterns of mRNA accumulation which correlate with changes in cuticle morphology and collagen protein composition during development. Our results suggest that, in general, there is a progressive activation of new collagen genes during normal development.

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