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

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.

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

Formate as an Inhibitor of Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 386-388 ◽  
Author(s):  
Jan F. H. Snel ◽  
Dirk Naber ◽  
Jack J. S. van Rensen
Keyword(s):  
Inhibitory Action ◽  
Electron Flow ◽  
Hill Reaction ◽  
Maximal Inhibition ◽  
Photosynthetic Electron Flow ◽  
The Hill

The effects of formate on the Hill reaction in isolated broken pea chloroplasts were in­vestigated. Addition of formate to chloroplasts has two distinct effects: I. basal electron flow can be stimulated 3-fold; 2. uncoupled electron flow is inhibited. The stimulating effect is due to uncoupling by formate and appears instantaneous. Maximal inhibition by form ate is only observed after prolonged illumination. The inhibitory action of form ate on electron flow can be relieved by bicarbonate *.

A new electron acceptor for the Hill reaction

1958 ◽  
Vol 76 (1) ◽  
pp. 233-234 ◽  
Author(s):  
James L. Hatchett ◽  
Rudolph J. Marcus
Keyword(s):  
Electron Acceptor ◽  
Hill Reaction ◽  
The Hill

Triaziflam and Diaminotriazine Derivatives Affect Enantioselectively Multiple Herbicide Target Sites

2001 ◽  
Vol 56 (7-8) ◽  
pp. 559-569 ◽  
Author(s):  
Klaus Grossmann ◽  
Stefan Tresch ◽  
Peter Plath
Keyword(s):  
Algal Cell ◽  
Cell Suspensions ◽  
Condensed State ◽  
Hill Reaction ◽  
Cellulose Synthesis ◽  
Root Tips ◽  
Multiple Test ◽  
Herbicide Atrazine ◽  
Sites Of Action ◽  
The Hill

Enantiomers of triaziflam and structurally related diaminotriazines were synthesized and their herbicidal mode of action was investigated. The compounds caused light and dark-dependent effects in multiple test systems including heterotrophic cleaver and photoautotrophic algal cell suspensions, the Hill reaction of isolated thylakoids and germinating cress seeds. Dose response experiments revealed that the (S)-enantiomers of the compounds preferentially inhibited photosystem II electron transport (PET) and algae growth with efficacies similar to that of the herbicide atrazine. In contrast, the (R)-enantiomers of the diaminotriazines were up to 100 times more potent inhibitors of growth in cleaver cell suspensions and cress seedlings in the dark than the (S)-enantiomers. The most active compound, the (R)-enantiomer of triaziflam, inhibited shoot and root elongation of cress and maize seedlings at concentrations below 1 μm. The meristematic root tips swelled into a club shape which is typical for the action of mitotic disrupter herbicides and cellulose biosynthesis inhibitors. Microscopic examination using histochemical techniques revealed that triaziflam (R)-enantiomer blocks cell division in maize root tips 4 h after treatment. The chromosomes proceeded to a condensed state of prometaphase but were unable to progress further in the mitotic cycle. Disruption of mitosis was accompanied by a loss of spindle and phragmoplast micotubule arrays. Concomitantly, cortical microtubules decreased which could lead to iso-diametric cell growth and consequently to root swelling. In addition, a decline in cellulose deposition in cell walls was found 24 h after treatment. Compared to the (R)-form, triaziflam (S)-enantiomer was clearly less active. The results suggest that triaziflam and related diaminotriazines affect enantioselectively multiple sites of action which include PET inhibitory activity, mitotic disruption by inhibiting microtubule formation and inhibition of cellulose synthesis

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