Chloroplast biogenesis: Determination of the molar extinction coefficients of divinyl chlorophyll a and b and their pheophytins

1992 ◽  
Vol 207 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Vinay P. Shedbalkar ◽  
Constantin A. Rebeiz
1978 ◽  
Vol 33 (1) ◽  
pp. 83-93 ◽  
Author(s):  
W. Hagele ◽  
D. Schmid ◽  
H. C. Wolf

The triplet state zero-field splittings and the rate constants for the population and depopulation of the triplet spin sublevels have been investigated for chlorophyll a and chlorophyll b in polymethylmethacrylate (PMMA) and methyltetrahydrofurane (MTHF) as a function of the concentration. In PMMA both chlorophyll a and chlorophyll b yielded only one ESR spectrum in the entire range of concentration which could be covered (1.5 × 10-5 - 1 × 10-3 mole/1). In MTHF the results were more complicated. At low concentrations (up to 103 mole/1) only one spectrum was observed, at higher concentrations additional spectra were detectable (all together two for chlorophyll a and five for chlorophyll b at 10-1 mole/1). The assignment of these spectra was facilitated by observing the "triplet resonance-field identity" which connects the resonancefield strengths for the canonical orientations of one particular species. Furthermore, the rate constants for some of these species could be determined.


2019 ◽  
Vol 2 (3) ◽  
pp. e00097
Author(s):  
T.V. Schäfer ◽  
A.A. Tyaptin ◽  
T.B. Pechurina

The goal of study was the determination of the ionization constants for the oximes – cholinesterases reactivators in aqueous solutions at different temperatures. The wavelengths of absorption maxima of the protonated and deprotonated oxime groups, the molar extinction coefficients of the various oximes species, and the ionization constants for the oxime cholinesterases reactivators (isonitrosin, pralidoxime, dipyroxime, toxogonin, methoxime, carboxime and asoxime) were obtained using spectrophotometric data (wavelength 190 to 450 nm) in solutions (pH 5 – 12) at 20°C, 25°C and 37°C. The proportion of nucleophilic forms involved in the oxime-induced reactivation of phosphorylated cholinesterases was shown to be is positively dependent on the incubation medium pH value and temperature. A hypothesis that the temperature affects the oximes ability to reactivate phosphorylated cholinesterases has been proposed.


2019 ◽  
Vol 20 (2) ◽  
pp. 615-620
Author(s):  
LISA MAWARNI ◽  
TENGKU CHAIRUN NISA ◽  
JUSTIN A NAPITUPULU ◽  
KARYUDI KARYUDI

Abstract. Mawarni L, Nisa TC, Napitupulu JA, Karyudi. 2019. Determination of leaf status of soybean varieties on shading. Biodiversitas 20: 615-620. The shading tolerant soybean varieties could be identified through the character growth such as leaf status. This study was aimed to obtain the shading tolerant of soybean variety based on their seed size and on the leaf status. Design of experiments was a split-plot design with three replications. The level of shading as the main plot with four levels of treatment was without shading, 30%, 50%, and 70% shading. Soybean varieties as the subplot had 4 genotypes namely Anjasmoro, Pangrango, Tanggamus, and Nanti wherein one variety comes with large seed; two come with medium seeds and the other one comes with small seed. The leaf status for determination was the greenness of leaves, the sum of chlorophyll a, chlorophyll b, total chlorophyll a and b, the forms of chloroplasts and leaf area. The soybean varieties with different seed sizes showed the differences only on the leaf area but not on leaf greenness or on the sum of chlorophyll. Nanti variety, having small seed, turns out to have the largest leaf area but is not shade tolerant. The large leaf area may be due to the forming of tetra foliate leaves on Nanti variety. The form of chloroplast of Anjasmoro variety in 70% shading is better than other varieties. Therefore, determining leaf status can identify shading tolerant of soybeans.


2011 ◽  
Vol 7 (S283) ◽  
pp. 324-325 ◽  
Author(s):  
Franco Cataldo ◽  
Susana Iglesias-Groth ◽  
Arturo Manchado

AbstractFullerenes, the carbon molecules with 60 and 70 atoms, were recently detected in a series of planetary nebulae, in protoplanetary nebulae and in other astrophysical objects. The detection and the quantitative determination of these molecules was made possible by the measurement of their reference infrared spectra and the relative molar extinction coefficients and integrated molar absorptivity on laboratory scale. It is expected that also fulleranes the hydrogenated derivatives of C60 and C70 may be present in the same objects where fullerenes were detected. This prompted us to synthesize the hydrogenated fullerenes, to record their infrared spectra and the measure the molar extinction coefficients and integrated molar absorptivity on laboratory scale to have a reference in the search of these fullerene derivatives in space


1995 ◽  
Vol 352 (5) ◽  
pp. 456-460 ◽  
Author(s):  
Iain L. Marr ◽  
Nana Suryana ◽  
Patrick Lukulay ◽  
Marcus I. Marr

1992 ◽  
Vol 31 (7) ◽  
pp. 1144-1147 ◽  
Author(s):  
Fanny S. Woo ◽  
Ricardo E. Rodriguez ◽  
Dale A. Huckaby ◽  
Peter Jones ◽  
Henry C. Kelly

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