Interactions Between Ferredoxin and Chlorophyll in a Monolayer System

1971 ◽  
Vol 26 (9) ◽  
pp. 922-929 ◽  
Author(s):  
Seymour Steven Brody

Ferredoxin (Fd) is surface active; both its area/molecule, A, and surface potential, ΔV, (at an air-water interface) vary with the pH of the subphase. From the surface isotherms (at pH 7.7) A and ΔV are 167 A2 and 170 ± 20 mV, respectively, when the surface tension is 10 dyne/cm.Fd and chlorophyll a (Chl) appear to form a mixed monomolecular film. At pH 7.7 a maximum interaction between Fd and Chl is observed when the monolayer contains a mole ratio of Fd/Chl ≅ 2. Irradiaion of Chl-Fd films, in nitrogen atmosphere, results in a bleaching of Chl and an increase of ΔV. The quantum yield for this bleaching is estimated to be 0.4.

1989 ◽  
Vol 56 (3) ◽  
pp. 487-494 ◽  
Author(s):  
Michael Wilson ◽  
Daniel M. Mulvihill ◽  
William J. Donnelly ◽  
Brian P. Gill

Summaryβ-Casein, was enzymically modified by incubation with plasmin to yield γ-caseins and proteose peptones. Whole γ-, γ1-, γ2/γ3-caseins and whole proteose peptone (pp) were isolated from the hydrolysate mixture. The time dependence of surface tension at the air-water interface of solutions of β-casein and its plasmin derived fragments, at concentrations of 10−1 to 10−4% (w/v) protein, pH 7.0, was determined, at 25 °C, using a drop volume apparatus. The ranking of the proteins with respect to rate of reduction of surface tension, during the first rate determining step, at 10-2% (w/v) protein, was γ2/γ3 ≫ pp > whole γ- > γ1- > β-casein. The ranking of the proteins with respect to surface pressures attained after 40 min (π40) was concentration dependent. γ2/γ3-Caseins were found to be very surface active, decreasing surface tension rapidly and giving a high π40. γ1 Casein decreased surface activity somewhat faster than β-casein, but generally reached a lower π40. Whole γ-casein reflected the properties of both γ1 and γ2/γ3-caseins. Proteose peptone was found to decrease surface tension rapidly during the initial rate determining step; it gave a relatively high π40 at a bulk phase concentration of 10−3% (w/v) protein, but, it was the least surface active protein at 10−1 and 10−2% (w/v) protein.


1973 ◽  
Vol 28 (3-4) ◽  
pp. 157-164 ◽  
Author(s):  
Seymour S. Brody

Monomolecular films of 9-cis, 11-cis, 13-cis and all-trans retinal were formed at an air-water interface. Area/molecule and surface potential were measured before, during and after illumination. The initial quantum yield of the photoisomerization of 9-cis retinal was 0.25. Irradiation of a retinal monolayer resulted in 30 to 60 mVolt changes in surface potential. Complexation of retinals with lysine and cysteine were studied.


Langmuir ◽  
2021 ◽  
Vol 37 (7) ◽  
pp. 2237-2255 ◽  
Author(s):  
Mengsu Peng ◽  
Timothy T. Duignan ◽  
Cuong V. Nguyen ◽  
Anh V. Nguyen

2000 ◽  
Vol 19 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Wieslaw I Gruszecki ◽  
Bogumil Zelent ◽  
Heidar-Ali Tajmir-Riahi ◽  
Gongming Wang ◽  
Toufik Taleb ◽  
...  

1994 ◽  
Vol 48 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
Fazale R. Rana ◽  
Suci Widayati ◽  
Brian W. Gregory ◽  
Richard A. Dluhy

The rate at which a monomolecular film is deposited onto a solid substrate in the Langmuir-Blodgett process of preparing supported monolayer films influences the final structure of the transferred film. Attenuated total reflectance infrared spectroscopic studies of monolayers transferred to germanium substrates show that the speed at which the substrate is drawn through the air/water interface influences the final conformation in the hydrocarbon chains of amphiphilic film molecules. This transfer-induced effect is especially evident when the monolayer is transferred from the expanded region of surface-pressure-molecular-area isotherms at low surface pressures; the effect is minimized when the film molecules are transferred from condensed phases at high surface pressures. This phenomenon has been observed for both a fatty acid and a phospholipid, which suggests that these conformational changes may occur in a variety of hydrocarbon amphiphiles transferred from the air/water interface. This conformational ordering may be due to a kinetically limited phase transition taking place in the meniscus formed between the solid substrate and aqueous subphase. In addition, the results obtained for both the phospholipid and fatty acid suggest that the structure of the amphiphile may help determine the extent and nature of the transfer-speed-induced structural changes taking place in the monomolecular film.


2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Dong Song ◽  
Baowei Song ◽  
Haibao Hu ◽  
Xiaosong Du ◽  
Peng Du ◽  
...  

Author(s):  
John Davenport

Post-larval specimens of Hirundichthys affinis are capable of jumping out of water, but the pectoral and pelvic fins are not extended when in air. Penetration through the air/ water interface demands a force to overcome surface tension which is similar in magnitude to the force required for the jump itself. However, post-larvae do not produce the single propulsive tail flick which powers the jump until most of the animal has passed through the interface. The post-larva emerges at an angle close to 45°, thus maximising the horizontal distance travelled before re-entry.Whether swimming slowly (4 body lengths s-1), or at maximum speed (36 body lengths s-1), post-larvae swim with the pectoral and pelvic fins extended. Calculations show that fast swimming post-larvae operate at Reynolds’ numbers of about 4×103, where surface roughness and projections decrease rather than increase drag.


Langmuir ◽  
1990 ◽  
Vol 6 (5) ◽  
pp. 1017-1023 ◽  
Author(s):  
J. L. Dote ◽  
W. R. Barger ◽  
F. Behroozi ◽  
E. L. Chang ◽  
S. L. Lo ◽  
...  

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