Transient light effects in the Hill reaction of disintegrating chloroplasts in vitro

Planta ◽  
1970 ◽  
Vol 93 (2) ◽  
pp. 89-105 ◽  
Author(s):  
G. Harnischfeger ◽  
H. Gaffron
Keyword(s):  
Hill Reaction ◽  
Light Effects ◽  
The Hill

THE CARBOXYLASES OF LEAVES AND THEIR ROLE IN PHOTOSYNTHESIS

1952 ◽  
Vol 30 (4) ◽  
pp. 395-409 ◽  
Author(s):  
K. A. Clendenning ◽  
E. R. Waygood ◽  
P. Weinberger
Keyword(s):  
Sugar Beet ◽  
Hydrogen Cyanide ◽  
Malic Enzyme ◽  
Hill Reaction ◽  
Leaf Extracts ◽  
Root Extracts ◽  
Phosphoglyceric Acid ◽  
Reaction Capacity ◽  
The Hill

"Malic" enzyme isolated from the cytoplasm of parsley and sugar beet leaves was linked with illuminated spinach chloroplast fragments to effect photosynthesis in vitro. The model photosynthesis system containing excess "malic" enzyme was not inhibited by 5 × 10−4 M hydrogen cyanide. The "malic" enzyme system was inhibited by cyanide, however, at very low enzyme concentrations. The richest source of "malic" enzyme found in this study was the mature parsley leaf. Expressed on the same basis, the enzymatic capacities of parsley leaf "malic" enzyme and the Hill reaction capacity of isolated spinach chloroplasts are of similar magnitude. Higher "malic" enzyme and oxalacetic carboxylase activities were found in purified extracts of parsley leaves than in the corresponding root extracts. Oxalacetic, oxalsuccinic, α-ketoglutaric, and pyruvic carboxylases were not inhibited by 10−3 M hydrogen cyanide. The α-ketoglutaric and pyruvic carboxylases were much less abundant in leaves than in other plant organs; formic dehydrogenase was not detected in leaves although it is abundant in seeds. Glutamic carboxylase was found in the cytoplasm of wheat and sugar beet leaves, and with the aid of C14O2 was shown to be only weakly reversible. No evidence was obtained for the presence in leaf extracts of an enzyme, or mixture of enzymes, capable of decarboxylating phosphoglyceric acid in vitro.

scholarly journals Isolation of chloroplasts in the Karwinskia species and determination of their photochemical activity under in vitro conditions

2011 ◽  
Vol 50 (No. 4) ◽  
pp. 149-156 ◽  
Author(s):  
M. Henselová ◽  
M. Regecová ◽  
A. Sováková
Keyword(s):  
Chlorophyll A ◽  
Photochemical Activity ◽  
Hill Reaction ◽  
Reaction Conditions ◽  
Significant Difference ◽  
The Hill ◽  
Isolated Chloroplasts ◽  
Photochemical Activity Of Chloroplasts

Reaction conditions for evaluation of the photochemical activity of isolated chloroplasts in the Hill reaction of Karwinskia humboldtiana (Roem &amp; Schut) Zucc. and Karwinskia parvifolia Rose species were determined. Hill&rsquo;s reaction activity was measured spectrophotometrically at 630 nm as the amount of DCPIP reduction by the chloroplast suspension at an irradiance of 400 &micro;mol/m<sup>2</sup>/sPAR. A significant difference was observed between the activity of chloroplasts isolated at 2&deg;C and 25&deg;C amounting to 27% in Karwinskia humboldtiana and 18.5% in K. parvifolia. After 24 hours of storage of chloroplasts at a suspension of 2&deg;C, a significant decrease of chloroplasts activity was noted in both species, e.g. 38% in Karwinskia humboldtiana and 45% in K. parvifolia. The photochemical activity of chloroplasts increased also with the length of irradiation of the reaction mixture and the content of chlorophyll (a + b) in chloroplast suspension. The activity of chloroplasts was found to be significantly higher in the species K. humboldtiana than in K. parvifolia and it proved higher in both when these were grown under field conditions rather than in a greenhouse.

Cyanoacrylate Inhibitors of the Hill Reaction V. The Effect of Chirality on Inhibitor Binding

1987 ◽  
Vol 42 (6) ◽  
pp. 684-689 ◽  
Author(s):  
John L. Huppatz ◽  
John N. Phillips
Keyword(s):  
Phenyl Ring ◽  
Alkyl Substituent ◽  
Receptor Site ◽  
Optically Active ◽  
Hill Reaction ◽  
Inhibitor Binding ◽  
Level Of Activity ◽  
The Difference ◽  
The Hill

Optically active α-methylbenzylamino 2-cyanoacrylic esters were synthesized and assayed as inhibitors of the Hill reaction in isolated pea chloroplast fragments. The 5-isomers were more potent inhibitors than the S-isomers with discriminations of from ten to greater than 100-fold being observed. A β-alkyl substituent in the cyanoacrylate molecule affected both the level of activity and the difference in activity between the isomers. An α,α-dimethylbenzylamino derivative was also active at about the same level as the corresponding α-methylbenzylamino racemate. This result could be explained in terms of the orientation of the phenyl ring in the receptor site. Replacement of the α-methylbenzylamino group by other α-alkyl and α-phenyl substituents had little effect on activity. However, an α-benzyl group was beneficial.

Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 374-377 ◽  
Author(s):  
J. J. S. van Rensen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
Amaranthus Hybridus ◽  
Apparent Affinity ◽  
Photosynthetic Electron Flow ◽  
Different Characteristics ◽  
The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

Metabolism of a Pyrrolidine Urea Herbicide in Corn and Weeds

Weed Science ◽  
1974 ◽  
Vol 22 (1) ◽  
pp. 10-14 ◽  
Author(s):  
R. E. Holm ◽  
D. E. Stallard
Keyword(s):  
Adventitious Roots ◽  
Parent Compound ◽  
Soil Surface ◽  
Abutilon Theophrasti ◽  
Water Soluble ◽  
Hill Reaction ◽  
Panicum Miliaceum ◽  
Proso Millet ◽  
Ipomoea Purpurea ◽  
The Hill

Five 2,5-dimethyl-1-pyrrolidinecarboxanilides were effective inhibitors of the Hill reaction. However, only thecisisomers were active; thetransisomers were totally inactive. Experiments were conducted using14C-5328 (cis-2,5-dimethyl-1-pyrrolidinecarboxanilide). A correlation existed between resistance of various plants to 5328 and their ability to metabolize it to water soluble metabolites. Velvetleaf (Abutilon theophrastiMedic.) and proso millet (Panicum miliaceumL.) seedlings were very susceptible to 5328 and were unable to metabolize it. Tall morningglory [Ipomoea purpurea(L.) Roth] seedlings were highly tolerant to 5328 and converted it completely to its metabolites. Corn (Zea maysL. ‘DeKalb variety XL-45′) seedlings which were slightly susceptible to 5328 injury were able to metabolize up to 90% of the parent compound. Corn foliage uptake of14C-5328 applied to the soil surface occurred through the adventitious roots.

scholarly journals Studies on the Second Emerson Effect in the Hill Reaction in Algal Cells

1961 ◽  
Vol 1 (5) ◽  
pp. 377-388 ◽  
Author(s):  
Rajni Govindjee ◽  
Eugene Rabinowitch
Keyword(s):  
Hill Reaction ◽  
The Hill

The mechanism of cyclic phosphorylation by illuminated chloroplasts

1963 ◽  
Vol 157 (968) ◽  
pp. 332-345 ◽  
Keyword(s):  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Reducing Power ◽  
Catalytic Amount ◽  
Adenosine Diphosphate ◽  
Hill Reaction ◽  
Hydrogen Transport ◽  
Hydrogen Acceptor ◽  
Light Reaction ◽  
The Hill ◽  
Evolution Of Oxygen

In the reaction discovered by Hill (1937, 1939), chloroplasts isolated from the cell were shown to be capable, upon illumination, of reducing an artificial hydrogen acceptor with the concurrent evolution of oxygen. The ‘Hill reaction’ was regarded as a partial model of the light reaction in photosynthesis where limited reducing power and molecular oxygen arose from the photolysis of water. Attempts to relate this reaction to the photochemical events preceding the dark reduction of carbon dioxide in photosynthesis received their first direct support from the finding of San Pietro & Lang (1958) that nicotinamide adenine dinucleotide phosphate ( NADP )can serve as an effective acceptor of hydrogen in the photochemical reaction when the system is supplemented with a catalytic amount of a soluble protein extracted from leaves. Added significance was given to this finding by the further observation of Amon, Whatley & Allen (1959), that hydrogen transport in the reaction could be coupled to the phosphorylation of adenosine diphosphate { ADP ) to yield adenosine triphosphate { ATP ) concurrently with the reduction of NADP and the production of oxygen in the stoicheiometric proportions: l NADP LL 2 jl ATP /^0 2 . They had previously demonstrated a similar coupling of phosphorylation to hydrogen transport when the artificial reagent, ferricyanide, served as hydrogen acceptor (Arnon, Whatley & Allen 1958). In this work, Amon et al. made the further important observation that hydrogen transport in the ferricyanide reaction is strongly stimulated when phosphorylation occurs concurrently.

Effect of salts on the Hill reaction in sonicated spinach chloroplasts

1974 ◽  
Vol 15 (4) ◽  
pp. 727-731 ◽  
Author(s):  
Kazuhiko Satoh ◽  
Atusi Takamiya ◽  
Sakae Katoh
Keyword(s):  
Hill Reaction ◽  
Spinach Chloroplasts ◽  
The Hill

scholarly journals In Vitro Pharmacodynamic Parameters of Sordarin Derivatives in Comparison with Those of Marketed Compounds against Pneumocystis carinii Isolated from Rats

2000 ◽  
Vol 44 (5) ◽  
pp. 1284-1290 ◽  
Author(s):  
Pablo Aviles ◽  
El-Moukhtar Aliouat ◽  
Antonio Martinez ◽  
Eduardo Dei-Cas ◽  
Esperanza Herreros ◽  
...  
Keyword(s):  
Pneumocystis Carinii ◽  
Maximum Effect ◽  
Drug Concentrations ◽  
Number Of Microorganisms ◽  
Immunosuppressed Patients ◽  
The Hill ◽  
Drug Free ◽  
Good Agreement

ABSTRACT Pneumocystis carinii pneumonia remains one of the most serious complications of immunosuppressed patients. In this study, the in vitro pharmacodynamic parameters of four sordarin derivatives (GM 191519, GM 237354, GM 193663, and GM 219771) have been evaluated by a new quantitative approach and compared with the commercially available drugs pentamidine, atovaquone, and trimethoprim-sulfamethoxazole (TMP-SMX). In vitro activities and in vivo therapeutic efficacies of sordarin derivatives against P. carinii were also evaluated. In vitro activity was determined by the broth microdilution technique, comparing the total number of microorganisms in treated and drug-free cultures by using Giemsa staining. The in vitro maximum effect (E max), the drug concentrations to reach 50% of E max(EC50), and the slope of the dose-response curve were then estimated by the Hill equation (E max sigmoid model). Sordarin derivatives were the most potent agents againstP. carinii, with EC50s of 0.00025, 0.0007, 0.0043, and 0.025 μg/ml for GM 191519, GM 237354, GM 193663, and GM 219771, respectively. The EC50s of pentamidine, atovaquone, and TMP-SMX were 0.025, 0.16, and 26.7/133.5 μg/ml, respectively. The results obtained with this approach showed GM 237354 and GM 191519 to be approximately 35- and 100-fold more active in vitro than pentamidine, the most active marketed compound. All sordarin derivatives tested were at least 5,000-fold more active in vitro than TMP-SMX. The three sordarin derivatives tested in vivo—GM 191519, GM 237354, and GM 219771—showed a marked therapeutic efficacy, defined as reduction of cyst forms per gram of lung. GM 191519 was the most potent (daily dose reducing 50% of the P. carinii burden in the lungs [ED50], 0.05 mg/kg/day) followed by GM 237354 and GM 219771 (ED50s, 0.30 and 0.49 mg/kg/day, respectively). Good agreement between in vitro parameters and in vivo outcome was obtained when P. carinii pneumonia in rats was treated with sordarin derivatives.

Sign in / Sign up

Export Citation Format

Share Document