scholarly journals Outstanding Photo-bioelectrochemical Cell by Integrating TiO2 and Chlorophyll as Photo-bioanode for Sustainable Energy Generation

2021 ◽  
Vol 11 (2) ◽  
pp. 385-391
Author(s):  
Marcelinus Christwardana ◽  
Athanasia Amanda Septevani ◽  
Linda Aliffia Yoshi
Keyword(s):  
Electron Transport ◽  
Chlorophyll Content ◽  
Water Oxidation ◽  
Spirulina Platensis ◽  
Chlorophyll Concentration ◽  
Photocurrent Density ◽  
The Other ◽  
Trapping Efficiency ◽  
Photosynthetic Organisms ◽  
Distinctive Structure

Photosynthesis is a technique for converting light energy into chemical energy that is both efficient and sustainable. Chlorophyll in energy-transducing photosynthetic organisms is unique because of their distinctive structure and composition. In photo-bioelectrochemical research, the chlorophyll's quantum trapping efficiency is attractive. Chlorophyll from Spirulina platensis is demonstrated to communicate directly with TiO2-modified Indium Thin Oxide (ITO) to generate electricity without the use of any mediator. TiO2-modified ITO with a chlorophyll concentration of 100 % generated the greatest power density and photocurrent of approximately 178.15 mW/m2 and 596.92 mA/m2 from water oxidation under light among all the other materials. While the sensitivity with light was 0.885 mA/m2.lux, and Jmax value was 1085 mA/m2. Furthermore, the power and photocurrent density as a function of chlorophyll content are studied. The polarizability and Van der Waals interaction of TiO2 and chlorophyll are crucial in enhancing electron transport in photo-bioelectrochemical systems. As a result, this anode structure has the potential to be improved and used to generate even more energy.

A New-Type Photosystem II Inhibitor which Blocks Electron Transport in Water-Oxidation System

1989 ◽  
Vol 44 (3-4) ◽  
pp. 271-279 ◽  
Author(s):  
H. Koike ◽  
T. Asami ◽  
S. Yoshida ◽  
N. Takahashi ◽  
Y. Inoue
Keyword(s):  
Electron Transport ◽  
Low Temperature ◽  
Photosystem Ii ◽  
Water Oxidation ◽  
Mode Of Action ◽  
The Other ◽  
Ps Ii ◽  
Abnormal Band ◽  
New Type ◽  
Oxidation System

Abstract The mode of action of three types of conjugated enamine compounds was investigated by means of thermoluminescence measurement. Cyanoacrylate and 2-(l-ethoxyethylam inom ethylidene)- 4-dodecyl-5,5-dim ethyl-cyclohexane-1,3-dione (ACm12) converted the B-band (30 °C) arising from S2QB- charge recombination to a downshifted 6 °C-band. This band was proved to be identical with the DCM U-induced Q-band (6 °C) arising from S2QA- recombination, indicating that these two compounds block QA to QB electron transport. 3-(1-dodecylam inopropyridene)-6- methyl-2H-pyran-2,4-dione (APp12 ), on the other hand, induced an abnormal band peaking at 15 °C between the Q-band and B-band. From the gradual downshift of its peak temperature in titration experiments, this band was assigned to arise from a modified S2QB- charge pair, in which the properties of either QB- or S2 is altered. The 15 °C-band showed normal oscillation during the first 2 flashes, but the oscillation was interrupted thereafter. Another therm oluminescence analysis by use of post flash low temperature illumination protocol revealed that APp12 affects neither QA to QB nor QB2- to PQ electron transport, but specifically blocks S3 to S0 transition. These results indicate that APp12 is a new-type PS II inhibitor.

Energy Conservation in Photoreductions by Photosystem II. Reversal of Dibromothymoquinone Inhibition of Hill-Reactions by Phenylenediamines

1973 ◽  
Vol 28 (11-12) ◽  
pp. 710-716 ◽  
Author(s):  
Achim Trebst ◽  
Susanne Reimer
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Water Oxidation ◽  
Photosynthetic Electron Transport ◽  
The Other ◽  
Ferricyanide Reduction ◽  
Other Hand ◽  
Transport Chain ◽  
Energy Conserving

Abstract The plastoquinone antagonist dibromothymoquinone interrupts the photosynthetic electron transport chain between photosystem II and I by inhibiting the oxidation of plastohydroquinone by photosystem I. The effect of phenylenediamines on NADP and ferricyanide photoreduction inhibited by dibromothymoquinone is studied in isolated chloroplasts. IV-substituted phenylene­ diamines fully restore NADPH and ATP formation as well as oxygen evolution in DBMIB inhibited NADP reduction, but are practically inactive in stimulating ferricyanide reduction by photo­ system II. On the other hand phenylenediamine and C-substituted phenylenediamines are only weakly active in restoring NADP reduction but are very active in stimulating ferricyanide reduc­ tion. The P/e2 ratio in restoration of NADP reduction by phenylenediamines is close to 1, whereas the P/e2 ratio in ferricyanide reduction is about 0.4 (the ratio is dependent on the DBMIB con­ centration). The reversal of the DBMIB inhibition in NADP reduction by phenylenediamines is attributed to a bypass of the inhibition site: Reduced phenylenediamines are electron donors for photosystem I after and oxidized phenylenediamines are electron acceptors for photosystem II be­ fore the DBMIB inhibition site. To explain the different rates and P/e2 ratios in the various systems it is assumed that all phenylenediamines are reduced at the expense of water oxidation by photo­ system II but via plastoquinone and on the inside of the membrane. Therefore two energy con­ serving steps (i. e. two proton releasing sites on the inside of the membrane) are involved, N-sub­ stituted phenylenediamines like TMPD reduced by photosystem II inside remain inside the mem­ brane and are reoxidized inside by photosystem I. This way they connect photosystem II bade onto photosystem I, electron transport rates are high and the P/e2 ratio is one in the restored NADP photoreduction. Phenylenediamine and C-substituted phenylenediamines on the other hand travel back to the outside through the membrane, and by doing so carry some of the protons released on the inside of the membrane by the energy conserving steps back to the outside. This way they are very active in stimulating the rate of ferricyanide photoreduction but the P/e2 ratio is only about 0.4. These phenylenediamines being removed from the inside are less active in restoring the rate of NADP reduction

Estimation of chlorophyll content by absorption spectra of native Spirulina platensis cells

2020 ◽  
pp. 25-33
Author(s):  
Leonid E. Paramonov
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Absorption Spectra ◽  
Spirulina Platensis ◽  
Intracellular Concentration ◽  
Absorption Coefficients

A method for retrieving the absorption coefficients of Spirulina platensis pigments using absorption spectra of native cells and excluding the use of extracts is considered. Estimates of the intracellular concentration of chlorophyll a, С-phycoerythrin, С- phycocyanin and allophycocyanin in native cells are discussed.

Morpho-Biochemical Characteristics of Brinjal Germplasms Affect the Abundance And Infestation of Jassid

2021 ◽  
Vol 19 (1) ◽  
pp. 81-91
Author(s):  
F Yasmin ◽  
MR Amin ◽  
M Afroz ◽  
MAH Swapon ◽  
MM Hossain
Keyword(s):  
Protein Content ◽  
Chlorophyll Content ◽  
Negative Correlation ◽  
Significant Positive Correlation ◽  
Significant Negative Correlation ◽  
Reducing Sugar ◽  
Total Sugar ◽  
The Other ◽  
Biochemical Characteristics ◽  
Positive Correlation

The tropical vegetable, brinjal is cultivated throughout the year in Bangladesh but the crop is infested by a number of insects including jassid. This study investigated the effects of different biophysical and biochemical characteristics of twelve brinjal germplasms on the abundance and infestation of jassid. The experiment was conducted during September 2018 to March 2019 in Gazipur, Bangladesh with twelve brinjal germplasms namely BD-7320, BD-7328, BD-9952, BD-10154, BD-10158, BARI Begun-1, BARI Begun-4, BARI Begun-5, BARI Begun- 6, BARI Begun-7, BARI Begun-8 and BARI Begun-9. The incidence of jassid was recorded from 3rd December to 26th March, and the lowest population was found on BARI Begun- 6. Among the biophysical traits, plant height, number of branch and leaf per plant, and leaf area exerted significant positive correlation; whereas trichome on lower and upper surfaces of leaf, spine per stem and leaf showed significant negative correlation with the abundance of jassid. On the other hand, moisture, reducing sugar, total sugar and protein content of the leaves and fruits, chlorophyll content of the leaves exerts significant positive correlation but ash and pH contents of the leaves and fruits were negatively correlated with the abundance of jassid. Jassids showed the lowest level of leaf infestation on BARI Begun-6, which could be for further analysis to develop jassid resistant brinjal. SAARC J. Agric., 19(1): 81-91 (2021)

Effect of Magnesium and Calcium Ions on the Photoelectron Transport Activity of Low-Salt Suspended Hydrilla verticillata Thylakoids: Possible Sites of Cation Interaction

1998 ◽  
Vol 53 (9-10) ◽  
pp. 849-856
Author(s):  
Sujata R. Mishra ◽  
Surendra Chandra Sabat
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Donor ◽  
Water Oxidation ◽  
Electron Flow ◽  
Hydrilla Verticillata ◽  
Transport Activity ◽  
Low Salt ◽  
Electron Transport Activity ◽  
Stimulation Of

Stimulatory effect of divalent cations like calcium (Ca2+) and magnesium (Mg2+) was investigated on electron transport activity of divalent cation deficient low-salt suspended (LS) thylakoid preparation from a submerged aquatic angiosperm, Hydrilla verticillata. Both the cations stimulated electron transport activity of LS-suspended thylakoids having an intact water oxidation complex. But in hydroxylamine (NH2OH) - or alkaline Tris - washed thylakoid preparations (with the water oxidation enzyme impaired), only Ca2+ dependent stimulation of electron transport activity was found. The apparent Km of Ca2+ dependent stimulation of electron flow from H2O (endogenous) or from artificial electron donor (exogenous) to dichlorophenol indophenol (acceptor) was found to be identical. Calcium supported stimulation of electron transport activity in NH2OH - or Tris - washed thylakoids was electron donor selective, i.e., Ca2+ ion was only effective in electron flow with diphenylcarbazide but not with NH2OH as electron donor to photosystem II. A magnesium effect was observed in thylakoids having an intact water oxidation complex and the ion became unacceptable in NH2OH - or Tris - washed thylakoids. Indirect experimental evidences have been presented to suggest that Mg2+ interacts with the water oxidation complex, while the Ca2+ interaction is localized betw een Yz and reaction center of photosystem II.

Photosynthetic and developmental traits associated with genotypic differences in durum wheat yield across the Mediterranean basin

2000 ◽  
Vol 51 (7) ◽  
pp. 891 ◽  
Author(s):  
D. Villegas ◽  
N. Aparicio ◽  
M.M. Nachit ◽  
J. L. Araus ◽  
C. Royo
Keyword(s):  
Durum Wheat ◽  
Chlorophyll Content ◽  
Mediterranean Basin ◽  
Carbon Isotope Discrimination ◽  
Canopy Temperature ◽  
Grain Filling ◽  
The Other ◽  
Early Vigour ◽  
Developmental Traits ◽  
The Mediterranean Basin

The relationships between various morphophysiological traits and yield were studied in durum wheat (Triticum durum Desf.) grown in Mediterranean conditions. Two sets of 22 genotypes were used. One was developed for semi-humid environments (TA-genotypes) and was cultivated in 22 trials around the Mediterranean basin with a mean yield across genotypes and environments of 4925 kg/ha. The other set was developed for drier conditions (CA-genotypes) and was cultivated in 15 trials, with a mean yield of 3501 kg/ha. Morphophysiological traits for each set were evaluated in 2 trials with contrasting water regimes conducted in north-eastern Spain: Lleida-rainfed (LR) and Lleida-irrigation (LI). Two kinds of traits were evaluated: developmental traits, including early vigour, plant height, and phenology (days from planting to heading and to maturity); and traits related to photosynthetic performance such as canopy temperature and chlorophyll content of the flag leaf, both measured during grain filling, and carbon isotope discrimination of mature grains. All the traits, measured in both Lleida trials, were related to the mean yield of the same genotypes across all the sites where they were cultivated. Yield measured at either of the 2 environments at Lleida was a much poorer predictor of genotype differences in mean yield than most of the traits. Nevertheless, the kind of environment where the morphophysiological traits were evaluated affected the performance of these traits as yield predictors. The combination of significant traits measured in the better environment (LI) explained 71% and 55% of genotype variability in yield within TA- and CA-genotypes, respectively, but only 56% and 27% when they were evaluated at LR. On the other hand, growing conditions of the yield trials was the main factor determining the best combination of traits. For TA-genotypes, larger yields were associated with shorter plants and higher carbon isotope discrimination (Δ) of grains, and to a lesser extent with higher early vigour and lower canopy temperature, whereas phenological traits made no contribution to explaining genotype differences in yield. For the CA-genotypes, higher yields were related to an earlier heading date or alternatively to a higher chlorophyll content during grain filling. A higher Δ in mature kernels also seems to be a positive trait.

scholarly journals The Influence of Iron Chelates on Chlorophyll Content and Yield of Bajra Napier

2021 ◽  
pp. 1-6
Author(s):  
S. S. Sangeetha ◽  
D. Jawahar ◽  
T. Chitdeshwari ◽  
C. Babu ◽  
L. Lakshmanan
Keyword(s):  
Chlorophyll Content ◽  
Iron Uptake ◽  
Ferrous Sulphate ◽  
Chlorophyll Concentration ◽  
Forage Crop ◽  
Fodder Yield ◽  
Four Levels ◽  
The Impact ◽  
Different Soils

Bajra Napier is an important forage crop. Numerous studies have reported a direct relationship between ferrite levels and physiological function of plants. The present study investigates the impact of iron sources and its levels on yield and chlorophyll content of Bajra Napier. The experiment was carried out in a Factorial CRD with 3 factors namely seven sources of Iron (Fe glycinate, Fe citrate, Fe tartrate, Fe glutamate, FeSO4, Fe-EDDHA, Fe malate) four levels (FeSO4 - 0, 25, 37.5 and 50 kg ha -1 and Fe chelates - 0, 1, 2.5 and 5 kg ha -1) and two different soils (Calcareous and Non-calcareous).The results revealed that the iron application increased the chlorophyll concentration and yield, and it was also seen that as the level increased there was an increase in both the characteristics. These results indicated that applying Fe chelates have significantly improved the quality of produce and it was seen that there was an improvement in the iron uptake and the fodder yield showed a greater increase when compared to ferrous sulphate.

Ferromagnetic–Antiferromagnetic Coupling Core–Shell Nanoparticles with Spin Conservation for Water Oxidation

2021 ◽  
Author(s):  
Jingjie Ge ◽  
Riccardo Ruixi Chen ◽  
Xiao Ren ◽  
Xia Li ◽  
Jiawei Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Transport ◽  
Domain Structure ◽  
Applied Magnetic Field ◽  
Water Oxidation ◽  
Rational Design ◽  
Critical Role ◽  
Antiferromagnetic Coupling ◽  
Core Shell ◽  
Multiple Domain

<p>Rational design of active oxygen evolution reaction (OER) catalysts is critical for the overall efficiency of water electrolysis. OER reactants and products’ differing spin states is one of causes to slow OER kinetics. Thus, spin conservation plays a crucial role in enhancing OER performance. In this work, we design ferromagnetic (FM)–antiferromagnetic (AFM) Fe<sub>3</sub>O<sub>4</sub>@Ni(OH)<sub>2</sub> core–shell catalysts. The interfacial FM–AFM coupling of these catalysts facilitates selective removal of electrons with spin direction opposing the magnetic moment of FM core, improving OER kinetics. The shell thickness is found critical in retaining the coupling effect for OER enhancement. The magnetic domain structure of the FM core also plays a critical role. With a multiple domain core, the applied magnetic field aligns the magnetic domains, optimising the electron transport process. A significant enhancement of OER activity is observed for the multiple domain core catalysts. With a single domain FM core with ordered magnetic dipoles, the spin-selective electron transport with minimal scattering is facilitated even without an applied magnetic field. We therefore draw a magnetism/OER activity model that depends on two main parameters: interfacial spin coupling and domain structure. Our findings provide new design principles for active OER catalysts.</p>

scholarly journals Nutrients Assimilation and Chlorophyll Contents for Different Grapevine Varieties in Calcareous Soils in the Somontano DO (Spain)

Beverages ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 90 ◽  
Author(s):  
José Casanova-Gascón ◽  
Pablo Martín-Ramos ◽  
Clara Martí-Dalmau ◽  
David Badía-Villas
Keyword(s):  
Chlorophyll Content ◽  
Fruit Set ◽  
Chlorophyll Concentration ◽  
Calcareous Soils ◽  
Pinot Noir ◽  
Growth And Yield ◽  
Cabernet Sauvignon ◽  
Chlorophyll Contents ◽  
Young Leaves ◽  
The Impact

Lime-induced chlorosis (LIC) is an important abiotic constraint affecting the growth and yield of grapevines growing in calcareous soils in the Mediterranean region, and the sensory properties of the produced wine. In the work presented herein, the impact of LIC on the nutritional status and chlorophyll content was assessed for eleven varieties and a clone (Merlot, Pinot Noir, Cabernet Sauvignon, Tempranillo, Parraleta, Moristel, Aglianico, Macabeo, Sauvignon, Chardonnay, and Riesling), grafted to the same rootstock (1103 Paulsen). Macro- and micronutrient contents were determined in the fruit set and veraison stages by petiole analyses, while chlorophyll content in young leaves was monitored by SPAD. Significant differences were detected amongst varieties for all nutrients (including Fe), and inverse relationships between Fe and P contents in the petiole and chlorophyll concentration in the young leaves were found. Regarding LIC resistance, the Fe and chlorophyll contents suggest that Cabernet Sauvignon, Tempranillo and Aglianico varieties would show the best performance, while Sauvignon would be the least tolerant.

scholarly journals Effect of Spirulina platensis on Lipid Profile of Long Evans Rats

1970 ◽  
Vol 45 (3) ◽  
pp. 249-254 ◽  
Author(s):  
M Omar Faruq Mridha ◽  
Parvin Noor ◽  
Rahima Khaton ◽  
Dipa Islam ◽  
Motaher Hossain
Keyword(s):  
Lipid Profile ◽  
Spirulina Platensis ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
The Other ◽  
High Fat ◽  
High Sugar ◽  
Group B ◽  
Group D ◽  
Effective Result

To study the Effect of Spirulina platensis on lipid profile of Long Evan rats, an experiment was conducted by feeding the rats with diets supplemented with Spirulina platensis dry powder. Five different types of diets were included in the feeding. Group A containing high fat and high sugar considered as control-01. Group B with high fat, high sugar and 0.5% Spirulina. Group C with high fat, high sugar and 2.5% Spirulina. These three groups were included in Diet-1. Group D with laboratory diets considered as control-02 and Group E i.e., laboratory diet with Spirulina 150mg/kg/body weight. These two groups were included in Diet-2. This study describes the useful effect of Spirulina powder after administration in high fat and high sugar diet and in normal laboratory diet. Spirulina platensis powder showed an effective result in the lipid profile of Long Evan rats. Total cholesterol (TC) serum lipid significantly reduced in Group B than that of 2.5% of Spirulina powder in Group C rats. 0.5% and 2.5% Spirulina powder had the same effect in dropping low density lipoprotein (LDL) in both B and C Groups of rats. Conversely 2.5% Spirulina powder was found more effective in increasing high density lipoprotein (HDL) in Group C (50.54%) rats than the group B (24.18%) rats. On the other hand, the dose 150mg/kg b.w Spirulina powder mixed in laboratory diet showed an effective result in decreasing total cholesterol (TC) and low density lipoprotein (LDL) 19.21% and 46.06%, respectively. The findings clearly indicated that 150mg/kg b.w Spirulina powder had positive effect to increase the value of high density lipoprotein (HDL) in Group E (24.98%) rats compare to control group D rats. There were no significant differences in diet-1 groups' TC, TG and LDL-C of the groups of A (control- 01), B and C (p<0.05), although they varies statistically for HDL among these groups (p>0.05). On the other hand in diet-2 groups' TG, LDL and HDL of E groups of rats were significantly varies than control-2 groups of rats D ( p>0.05), although TC was not significant statistically (p<0.05). Keywords: High fat diet; Body weight (b.w); Hypercholesterolemia; Hypolipidaemic; Spirulina platensis. DOI: 10.3329/bjsir.v45i3.6533Bangladesh J. Sci. Ind. Res. 45(3), 249-254, 2010

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