scholarly journals Regulation of the activity of adenylate cyclases by hydrogen peroxide in pea root cells Infected with pathogens and a mutualist

2020 ◽  
Vol 10 (3) ◽  
pp. 450-458
Author(s):  
O. V. Kuzakova ◽  
L. A. Lomovatskaya ◽  
A. S. Romanenko ◽  
A. M. Goncharova
Keyword(s):  
Hydrogen Peroxide ◽  
Pseudomonas Syringae ◽  
Rhizobium Leguminosarum ◽  
Mutual Influence ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Plant Signaling ◽  
Clavibacter Michiganensis ◽  
Root Cells ◽  
Pea Root

This study examines the effect of a range of exogenous concentrations of hydrogen peroxide on the activity of transmembrane and soluble adenylate cyclases (EC 4.6.1.1) contained in root cells of pea seedlings infected with one of the following: Rhizobium leguminosarum bv. Viciae, Pseudomonas syringae pv. Pisi, and Clavibacter michiganensis ssp. sepedonicus. The results showed that the pool of intracellular H2O2 increased when pea roots were infected with bacteria regardless of type. The study analysed the concentration of intracellular cyclic adenosine monophosphate, a product of the adenosine triphosphate cyclization reaction catalyzed by transmembrane and soluble adenylate cyclases. The concentration of intracellular cyclic adenosine monophosphate increased when infected with either Rhizobium leguminosarum bv. viciae or Clavibacter michiganensis ssp. Sepedonicus; however, the concentration decreased by 20% when infected with Pseudomonas syringae pv. Pisi. The in vitro activity of soluble and transmembrane adenylate cyclases from pea root cells inoculated with Rhizobium leguminosarum bv. viciae was H2O2 dose-dependent: 100 nM of H2O2 reduced the activity of soluble and transmembrane adenylate cyclases slightly, while 26 µM inhibited their activity by 50–60%. When infected with Pseudomonas syringae pv. pisi, the reduction in the activity of soluble and transmembrane adenylate cyclases was independent of the concentrations of H2O2 in the range investigated. When infected with Clavibacter michiganensis ssp. sepedonicus, 100 nM of H2O2 inhibited the activity of transmembrane adenylate cyclases, although enhancing the activity of soluble adenylate cyclases. On the contrary, concentrations of H2O2 of 2.6 and 26 µM increased the activity of transmembrane adenylate cyclases and inhibited the activity of soluble adenylate cyclases. It can be concluded that the specific concentration of second messengers in plant cells depends on the specificity of the biotic stressor and forms, inter alia, by their mutual influence on the components of other plant signaling systems.

Effect of exogenous hydrogen peroxide on iodide transport and iodine organification in FRTL-5 rat thyroid cells

1993 ◽  
Vol 129 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Ge Chen ◽  
A Eugene Pekary ◽  
Masahiro Sugawara ◽  
Jerome M Hershman
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Thyroid Peroxidase ◽  
Thyroid Cells ◽  
Iodide Transport ◽  
Biphasic Effect ◽  
Rat Thyroid ◽  
Camp Levels ◽  
Hormone Formation

Hydrogen peroxide plays an important role in the regulation of iodination and thyroid hormone formation. In the present study, the effect of exogenous H2O2 on 125I transport and organification was investigated in FRTL-5 rat thyroid cells. Less than 20 passages after subcloning, cells in 24-well plates (6 × 104 cells/well) were maintained in a thyrotropin (TSH)-containing medium (6H) for 3 days. A TSH-free medium (5H) was then used for the next 7 days. A 1-h exposure to H2O2 stimulated 125I transport and 125I organification at 0.1–0.5 mmol/l H2O2 and had a toxic effect on FRTL-5 cells at 5 mmol/l. Hydrogen peroxide (0.5 mmol/l) augmented the iodide transport and iodine organification induced by TSH (333U/l) by two- and threefold, respectively. The biphasic effect of H2O2 was blocked totally by 5–200 μg/l of catalase. Catalase by itself did not influence TSH-mediated 125I transport and 125I organification. Hydrogen peroxide (0.5 mmol/l) added to cells in 5H medium increased Na+K+-ATPase activity twofold. Ouabain (1 mmol/l), an inhibitor of Na+K +-ATPase, completely inhibited the twofold increase in 125I transport induced by 0.5 mmol/l H2O2 but only inhibited H2O2-induced 125I organification by 28%. Methimazole (1 mmol/l), an inhibitor of thyroid peroxidase, had no effect on H2O2-mediated 125I transport but totally blocked the fivefold rise in 125I organification induced by 0.5 mmol/1 H2O2. The effect of H2O2 on intracellular cyclic adenosine monophosphate (cAMP) levels also was studied. Hydrogen peroxide (0.5 mmol/l) decreased baseline and 160 mU/l TSH-induced cAMP levels by 35 and 87%, respectively, while a 3-h incubation with 0.5 mmol/l H2O2 increased Na + K +-ATPase in 5H and 6H media. We conclude that H2O2 plays an important role in the regulation of iodide transport and organification and also may affect signal transduction and the electrochemical gradient in thyroid cells. Our results also provide evidence that functional thyroid peroxidase activity is present in FRTL-5 cells.

АКТИВНОСТЬ АДЕНИЛАТЦИКЛАЗ И ИЗМЕНЕНИЕ КОНЦЕНТРАЦИИ ЦАМФ В КЛЕТКАХ КОРНЯ ПРОРОСТКОВ ГОРОХА ПРИ ИНФИЦИРОВАНИИ МУТУАЛИСТАМИ И ФИТОПАТОГЕНАМИ, "Физиология растений"

2018 ◽  
pp. 310-320
Author(s):  
Л.А. Ломоватская ◽  
О.В. Кузакова ◽  
А.С. Романенко ◽  
А.М. Гончарова
Keyword(s):  
Pseudomonas Syringae ◽  
Rhizobium Leguminosarum ◽  
Clavibacter Michiganensis

Изучали интенсивность сорбции азотфиксирующего симбионта, Rhizobium leguminosarum bv. vicea (Rlv), а также специфического, Pseudomonas syringae pv. pisi (Psp), и неспецифического, Clavibacter michiganensis ssp. sepedonicus (Cms), фитопатогенов, в различных зонах корня проростка гороха. Ранее установлено, что эти зоны (I - меристема 2 мм; II зона без корневых волосков - 27 мм; III зона, содержащая зачатки корневых волосков 712 мм; IV зона молодых корневых волосков - 1217 мм; V зона закончивших рост корневых волосков -1722 мм от кончика корня) отличались по чувствительности к Rlv. При этом исследовали реакцию отдельных компонентов аденилатциклазной сигнальной системы (АСС): изменение концентрации циклического аденозинмонофосфата (цАМФ), активности трансмембранной аденилатциклазы (тАЦ) и растворимой аденилатциклазы (рАЦ) в тех же зонах корня гороха через различные промежутки времени инфицирования (5, 15, 120 и 360 мин). Показано, что степень активации отдельных компонентов АСС клеток различных зон корня проростков гороха не зависела от интенсивности сорбции бактерий разной специализации. Под воздействием Rlv характер изменения активности тАЦ и рАЦ практически совпадал в различных зонах корня гороха и был близок к динамике изменения уровня цАМФ в тех же условиях. При контакте с Psp изменение уровня цАМФ было схоже с аналогичным показателем при инфицировании Rlv, а динамика тАЦ и рАЦ в большинстве случаев имела противоположную направленность. При контакте с Cms, несмотря на отсутствие сорбции, происходило повышение уровня цАМФ и наблюдалась активация тАЦ и рАЦ. Предполагается, что изменение активности упомянутых компонентов АСС связано с экзометаболитами Rlv, Psp и Cms, которые активируют PAMP-индуцированный иммунитет клеток проростков гороха. Одинаковая динамика цАМФ в различных зонах корня проростков гороха под воздействием Rlv и Psp отражает специфическую реакцию и имеет, вероятно, различную функцию: при контакте с Rlv - регуляторную, с Psp - защитную. При кратковременном воздействии Cms динамика изменения цАМФ в тех же зонах корня носит неспецифический характер, и, возможно, связана с интенсивностью поглощения экзополисахаридов (ЭПС) корневыми волосками. Системная реакция АСС наблюдалась также в гипокотиле проростков под воздействием всех трех микроорганизмов.

Mechanisms of ATP to cAMP Conversion Catalyzed by the Mammalian Adenylyl Cyclase: A Role of Magnesium Coordination Shells and Proton Wires

2019 ◽  
Author(s):  
Bella Grigorenko ◽  
Igor Polyakov ◽  
Alexander Nemukhin
Keyword(s):  
Adenylyl Cyclase ◽  
Bond Cleavage ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Md Simulations ◽  
Coordination Shell ◽  
Energy Profile ◽  
One Step ◽  
Type V

<p>We report a mechanism of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP) conversion by the mammalian type V adenylyl cyclase revealed in molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) simulations. We characterize a set of computationally derived enzyme-substrate (ES) structures showing an important role of coordination shells of magnesium ions in the solvent accessible active site. Several stable six-fold coordination shells of Mg<sub>A</sub><sup>2+ </sup>are observed in MD simulations of ES complexes. In the lowest energy ES conformation, the coordination shell of Mg<sub>A</sub><sup>2+ </sup>does not include the O<sub>δ1</sub> atom of the conserved Asp440 residue. Starting from this conformation, a one-step reaction mechanism is characterized which includes proton transfer from the ribose O<sup>3'</sup>H<sup>3' </sup>group in ATP to Asp440 via a shuttling water molecule and P<sup>A</sup>-O<sup>3A</sup> bond cleavage and O<sup>3'</sup>-P<sup>A</sup> bond formation. The energy profile of this route is consistent with the observed reaction kinetics. In a higher energy ES conformation, Mg<sub>A</sub><sup>2+</sup> is bound to the O<sub>δ1</sub>(Asp440) atom as suggested in the relevant crystal structure of the protein with a substrate analog. The computed energy profile initiated by this ES is characterized by higher energy expenses to complete the reaction. Consistently with experimental data, we show that the Asp440Ala mutant of the enzyme should exhibit a reduced but retained activity. All considered reaction pathways include proton wires from the O<sup>3'</sup>H<sup>3' </sup>group via shuttling water molecules. </p>

Polydatin Attenuates Carbachol-induced Contraction of Guinea Pig Gallbladder

2019 ◽  
Vol 18 (1) ◽  
pp. 34-38
Author(s):  
Chen Lei ◽  
Pan Xiang ◽  
Shen Yonggang ◽  
Song Kai ◽  
Zhong Xingguo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Guinea Pig ◽  
Smooth Muscles ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Dependent Manner ◽  
Underlying Mechanisms ◽  
Dose Dependent

The aim of this study was to determine whether polydatin, a glucoside of resveratrol isolated from the root of Polygonum cuspidatum, warranted development as a potential therapeutic for ameliorating the pain originating from gallbladder spasm disorders and the underlying mechanisms. Guinea pig gallbladder smooth muscles were treated with polydatin and specific inhibitors to explore the mechanisms underpinning polydatin-induced relaxation of carbachol-precontracted guinea pig gallbladder. Our results shown that polydatin relaxed carbachol-induced contraction in a dose-dependent manner through the nitric oxide/cyclic guanosine monophosphate/protein kinase G and the cyclic adenosine monophosphate/protein kinase A signaling pathways as well as the myosin light chain kinase and potassium channels. Our findings suggested that there was value in further exploring the potential therapeutic use of polydatin in gallbladder spasm disorders.

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