scholarly journals Fitotoksyczność herbicydów z grupy symetrycznych trójazyn na tle ich struktury i mechanizmu działania inhibicyjnego na reakcje Hilla [Phytotoxicitil of symetrical triazine herbicides against the background of their structures and the mechanism of their inhibitory effect on the Hill reaction]

2015 ◽  
Vol 22 (1) ◽  
pp. 27-42
Author(s):  
Michał Płoszyński
Keyword(s):  
Inhibitory Effect ◽  
Hill Reaction ◽  
Triazine Herbicides ◽  
The Hill

scholarly journals Effect of herbicides on photosynthetic electron transport and on the growth of the alga Scenedesmus quadricauda

2015 ◽  
Vol 45 (1–2) ◽  
pp. 101-110
Author(s):  
W. Hendrich ◽  
Z> Kubiak ◽  
K. Jurajda ◽  
M. Pawlaczyk-Szpilowa
Keyword(s):  
Electron Transport ◽  
Mechanism Of Action ◽  
Photosynthetic Electron Transport ◽  
Inhibitory Effect ◽  
Scenedesmus Quadricauda ◽  
Hill Reaction ◽  
The Hill ◽  
Alga Scenedesmus Quadricauda

The inhibitory effect of herbicides on the Hill reaction (with 2,6-dichloro-phenol-indophenol as acceptor) and their influence on development of the alga <i>Scenedesmus quadricauda</i> was studied. The following herbicides were tested: 2,4-D, Gramoxone, Afalon, Kresamone, CIPC and Simazine. The results are discussed in terms of the mechanism of action of the investigated herbicides.

Transducing mechanisms between circadian clock and overt rhythms in Gonyaulax

1969 ◽  
Vol 47 (2) ◽  
pp. 299-308 ◽  
Author(s):  
Beatrice M. Sweeney
Keyword(s):  
Electron Flow ◽  
Calvin Cycle ◽  
Continuous Light ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Hill Reaction ◽  
Enzyme Preparations ◽  
Dimethyl Urea ◽  
The Hill

In Gonyaulax polyedra it is possible to measure overt rhythms in luminescence, photosynthesis, and cell division. A common endogenous oscillator appears to control all three processes. The question of concern here is the manner in which the information regarding period and phase is transduced from oscillator to overt rhythm. In the rhythm of photosynthetic capacity, the path of electron flow through systems I and II appears not to be the site of transduction, since there is no rhythm in cells in flashing light, in the Hill reaction, or in sensitivity to such specific inhibitors as dichlorophenyl dimethyl urea (DCMU), and carbonyl cyanide m-chlorophenylhydrazone (CCmP). The probable site of control is in the Calvin cycle, since the activity of the first enzyme in this cycle, ribulose diphosphate dicarboxylase, varies with the phase of the cells from which the enzyme is derived. The low activity of this enzyme in crude extracts from cells in the night phase in continuous light can be overcome by increasing the concentration of bicarbonate in the reaction mixture. In vivo also, increasing the concentration of bicarbonate decreases the amplitude of the rhythm markedly. The activity of mixtures of extracts prepared during the day and the night phase is intermediate between that of either enzyme preparation alone, suggesting that the differences in activity are not caused by the presence of activators or inhibitors. The activity of ribulose diphosphate carboxylase is reduced by high temperature and by the presence of parachloromercuribenzonate (pCMB) and both adenosine triphosphate (ATP) and adenosine diphosphate (ADP), but differences in sensitivity to inhibitors between "day" and "night" enzyme preparations are not observed. The concentration of ATP extractable from cells does not vary with the phase of the rhythm.Transduction in the luminescent rhythm appears to be via changes in the mechanism by which luminescence is stimulated in vivo, since it is possible to obtain large and almost equal amounts of light from cells throughout the rhythmic cycle by the addition of acid. Eliciting luminescence in this way appears to bypass the normal mechanism of stimulation. This conclusion is strengthened by the observation that the inhibitory effect of light on cell luminescence is also eliminated when acid is used.

Basis for Synergism of Atrazine and Alachlor Combinations on Japanese Millet

Weed Science ◽  
1975 ◽  
Vol 23 (1) ◽  
pp. 43-48 ◽  
Author(s):  
I. O. Akobundu ◽  
W. B. Duke ◽  
R. D. Sweet ◽  
P. L. Minotti
Keyword(s):  
Protein Synthesis ◽  
Synergistic Effect ◽  
Inhibitory Effect ◽  
Hill Reaction ◽  
Chloroplast Protein ◽  
Physiological Processes ◽  
Herbicide Mixture ◽  
The Hill ◽  
Hill Reaction Activity ◽  
Chloroplast Protein Synthesis

The effect of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] combinations on various physiological processes was studied in order to establish a basis for the synergistic effect of this mixture on Japanese millet [Echinochloa crus-galli(L.) Beauv. var.frumentaceaL.]. In contrast to atrazine, alachlor had no effect on the Hill reaction activity of isolated Japanese millet chloroplasts. When used in combination with atrazine, alachlor had no influence on the inhibitory effect of atrazine on the Hill reaction. Atrazine and alachlor combinations reduced chloroplast protein and severely inhibited chloroplast protein synthesis relative to protein synthesis by other particulate fractions. This inhibition appears to be the basis for the synergistic effect of this herbicide mixture on Japanese millet. Although the mechanism of action of the herbicide mixture is not understood, it does not seem to involve inhibition of atrazine detoxification.

Light-induced inhibition of sporangial formation of Phytophthora infestans on potato leaves

1975 ◽  
Vol 53 (22) ◽  
pp. 2680-2686 ◽  
Author(s):  
Yigal Cohen ◽  
Helena Eyal ◽  
Tova Sadon
Keyword(s):  
Phytophthora Infestans ◽  
Blue Light ◽  
Red Light ◽  
Continuous Light ◽  
Inhibitory Effect ◽  
Hill Reaction ◽  
Light Conditions ◽  
Temperature Dependent ◽  
Dimethyl Urea ◽  
The Hill

Phytophthora infestans failed to produce sporangia on infected potato leaves under continuous light conditions. Blue light (λmax = 450 nm) was most inhibitory, while red light (λmax = 650 nm) was ineffective in inhibiting sporangial formation. Low intensity of blue light (3.7 μEinstein m−2 s−1) induced about 85% inhibition. The inhibitory effect of blue light upon sporulation was temperature dependent: it increased with rise in the temperature from 10 °C to 25 °C. 3,3,4-Dichlorophenyl-1,1-dimethyl urea (DCMU), which blocks the Hill reaction of photosynthesis, did not enable the fungus to sporulate on leaves under light conditions. Preceding dark treatments did not remove the inhibitory effect of blue light; this suggested that sporulation of the fungus is not a 'dark induction phenomenon.'

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.

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