scholarly journals Comparative analysis of the biosynthesis of isoprenoid and aromatic cytokinins

2019 ◽  
Vol 488 (6) ◽  
pp. 673-676
Author(s):  
V. E. Oslovsky ◽  
E. M. Savelieva ◽  
M. S. Drenichev ◽  
G. A. Romanov ◽  
S. N. Mikhailov
Keyword(s):  
Test System ◽  
Cytokinin Activity ◽  
In Planta ◽  
Similar Activity ◽  
Model Plant Arabidopsis Thaliana ◽  
Aromatic Cytokinins ◽  
Derivatives Of ◽  
Ribose Moiety ◽  
Plant Arabidopsis Thaliana

To compare the biosynthesis pathways of aromatic and isoprenoid cytokinins, a series of nucleoside derivatives of natural cytokinins was synthesized and their cytokinin activity was determined in a test system based on the model plant Arabidopsis thaliana. Cytokinin nucleosides are known to lack the hormonal activity until cleaving the ribose moiety at the position 9. Our experiments have shown that both ribo- and 5-deoxyribo derivatives of N 6-isopentenyladenine were able to turn into active cytokinins in planta exhibiting cytokinin activity. By contrast, 5-deoxy nucleosides of aromatic cytokinins did not show similar activity. Since 5-deoxy nucleosides cannot phosphorylate in vivo, the direct pathway of active cytokinin formation by cleavage of nucleotides is blocked here. The detected activity in 5-deoxy nucleosides of isoprenoid cytokinins and the lack of the activity in 5-deoxy nucleosides of aromatic cytokinins indicates a difference in the biosynthesis of these compounds.

scholarly journals Distinct Peculiarities of In Planta Synthesis of Isoprenoid and Aromatic Cytokinins

Biomolecules ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 86
Author(s):  
Vladimir Oslovsky ◽  
Ekaterina Savelieva ◽  
Mikhail Drenichev ◽  
Georgy Romanov ◽  
Sergey Mikhailov
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Cells ◽  
Cytokinin Activity ◽  
Hormonal Activity ◽  
In Planta ◽  
Significant Difference ◽  
Aromatic Cytokinins ◽  
Derivatives Of ◽  
Ribose Moiety

The biosynthesis of aromatic cytokinins in planta, unlike isoprenoid cytokinins, is still unknown. To compare the final steps of biosynthesis pathways of aromatic and isoprenoid cytokinins, we synthesized a series of nucleoside derivatives of natural cytokinins starting from acyl-protected ribofuranosyl-, 2′-deoxyribofuranosyl- and 5′-deoxyribofuranosyladenine derivatives using stereoselective alkylation with further deblocking. Their cytokinin activity was determined in two bioassays based on model plants Arabidopsis thaliana and Amaranthus caudatus. Unlike active cytokinins-bases, cytokinin nucleosides lack the hormonal activity until the ribose moiety is removed. According to our experiments, ribo-, 2′-deoxyribo- and 5′-deoxyribo-derivatives of isoprenoid cytokinin N6-isopentenyladenine turned in planta into active cytokinins with clear hormonal activity. As for aromatic cytokinins, both 2′-deoxyribo- and 5′-deoxyribo-derivatives did not exhibit analogous activity in Arabidopsis. The 5′-deoxyribo-derivatives cannot be phosphorylated enzymatically in vivo; therefore, they cannot be “activated” by the direct LOG-mediated cleavage, largely occurring with cytokinin ribonucleotides in plant cells. The contrasting effects exerted by deoxyribonucleosides of isoprenoid (true hormonal activity) and aromatic (almost no activity) cytokinins indicates a significant difference in the biosynthesis of these compounds.

scholarly journals In vivo efficacies of 5'-methylthioadenosine analogs as trypanocides.

1997 ◽  
Vol 41 (10) ◽  
pp. 2108-2112 ◽  
Author(s):  
C J Bacchi ◽  
K Sanabria ◽  
A J Spiess ◽  
M Vargas ◽  
C J Marasco ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
East African ◽  
Trypanosoma Brucei Rhodesiense ◽  
Polyamine Biosynthesis ◽  
Substrate Analogs ◽  
Osmotic Pumps ◽  
Derivatives Of ◽  
Ribose Moiety

5'-Deoxy-5'-(methylthio)adenosine (MTA), a key by-product of polyamine biosynthesis, is cleaved by MTA phosphorylase and is salvaged as adenine and, through conversion of the ribose moiety, methionine. An analog of MTA, 5'-deoxy-5'-(hydroxyethylthio)adenosine (HETA), is a substrate for trypanosome MTA phosphorylase and is active in vitro and in vivo against Trypanosoma brucei brucei, an agent of bovine trypanosomiasis. In this study, HETA and three O-acylated HETA derivatives were examined for their activities against model infections of T. b. brucei and Trypanosoma brucei rhodesiense, the agent of East African sleeping sickness. HETA was curative (>60%) for infections caused by 5 of 11 clinical isolates of T. b. rhodesiense when it was given to mice at 200 mg/kg of body weight for 7 days as a continuous infusion in osmotic pumps. HETA at 150 to 200 mg/kg also extended the life spans of the mice infected with four additional isolates two- to fivefold. Di- and tri-O-acetylated derivatives of HETA also proved curative for the infections, while a tri-O-propionyl derivative, although also curative, was not as effective. This study indicates that substrate analogs of MTA should be given important consideration for development as novel chemotherapies against African trypanosomiasis.

Commercially available analogues of GnRH and LH secretion

1988 ◽  
Vol 119 (3) ◽  
pp. 345-352 ◽  
Author(s):  
T. R. Koiter ◽  
H. Moes ◽  
G. A. Schuiling
Keyword(s):  
Clinical Trials ◽  
Test System ◽  
In Vitro Test ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Vitro Test ◽  
Lh Secretion ◽  
Derivatives Of

Abstract. Six agonistic derivatives of GnRH, four of which have already been evaluated in clinical trials, were compared with GnRH itself in an in vitro test system (incubation of rat pituitary glands). It was investigated 1) how the release of LH was affected when the pituitary glands were incubated in the presence of these analogues or GnRH, and 2) how the release of LH continued after removal of the analogues or GnRH from the medium. It was also investigated how an in vivo pretreatment for 6 days with several doses of 5 of these analogues or GnRH affects 3) the plasma concentration of LH, 4) the pituitary content of LH, and, in vitro, 5) the autonomous and 6) agonist-stimulated secretion of LH. Each of the analogues showed for each of the six investigated parameters a 10- to 100-fold higher potency than GnRH itself. Between the six analogues there were only minor differences. It is discussed how the six investigated parameters may be the expression of one single property of all these analogues, namely a long retention in the pituitary gland with a strong binding to the GnRH receptor.

scholarly journals Cytokinin activity ofN6-benzyladenine derivatives assayed by interaction with the receptorsin planta, in vitro, andin silico

2018 ◽  
Author(s):  
Ekaterina M. Savelieva ◽  
Vladimir E. Oslovsky ◽  
Dmitry S. Karlov ◽  
Nikolay N. Kurochkin ◽  
Irina A. Getman ◽  
...  
Keyword(s):  
Specific Binding ◽  
Biological Effects ◽  
Test System ◽  
Membrane Receptors ◽  
Receptor Interaction ◽  
Cytokinin Activity ◽  
Interaction Patterns ◽  
In Planta ◽  
Cytokinin Receptors

AbstractBiological effects of hormones in both plants and animals are based on high-affrnity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived inArabidopsisby three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin–receptor interaction, we used 25 derivatives of potent cytokininN6-benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors fromArabidopsis. The mainin plantaassay system was based onArabidopsisdouble mutants retaining only one isoform of cytokinin receptors and harboring cytokinin-sensitive reporter gene. Classical cytokinin biotest withAmaranthusseedlings was used as an additional biotest. In parallel, the binding of ligands to individual cytokinin receptors was assessed in thein vitrotest system. Quantitative comparison of results of different assays confirmed the partial similarity of ligand-binding properties of receptor isoforms. Substituents at positions 8 and 9 of adenine moiety, elongated linker up to 4 methylene units, replacement ofN6by sulfur or oxygen, resulted in suppression of cytokinin activity of the derivative towards all receptors. Introduction of a halogen into position 2 of adenine moiety, on the contrary, often increased the ligand activity, especially toward AHK3. Features both common and distinctive of cytokinin receptors inArabidopsisandAmaranthuswere revealed, highlighting species specificity of the cytokinin perception apparatus. Correlations between extent of compound binding to a receptorin vitroand its ability to activate the same receptorin plantawere evaluated for each AHK protein. Interaction patterns between individual receptors and ligands were rationalized by structure analysis and molecular docking in sensory modules of AHK receptors. The best correlation between docking scores and specific binding was observed for AHK3. In addition, receptor-specific ligands have been discovered with unique properties to predominantly activate or block distinct cytokinin receptors. These ligands are promising for practical application and as molecular tools in the study of the cytokinin perception by plant cells.Graphical abstractIndividual cytokinin receptors fromArabidopsiswere assayedin planta,in vitroandin silicowith 25 different 6-benzyladenine derivatives, new receptor-specific cytokinins were revealed.

Acyl-Enzymes as Thrombolytic Agents in Dog Models of Venous Thrombosis and Pulmonary Embolism

1984 ◽  
Vol 51 (02) ◽  
pp. 248-253 ◽  
Author(s):  
R J Dupe ◽  
P D English ◽  
R A G Smith ◽  
J Green
Keyword(s):  
Pulmonary Embolism ◽  
Side Effects ◽  
Venous Thrombosis ◽  
Active Site ◽  
Acute Pulmonary Embolism ◽  
Quantitative Model ◽  
Beagle Dog ◽  
Thrombosis Model ◽  
Derivatives Of

SummaryA quantitative model of venous thrombosis in the beagle dog is described. The model was adapted to permit ageing of isolated experimental clots in vivo. A model of acute pulmonary embolism in this species is also described. In the venous thrombosis model, infusion of streptokinase (SK) or SK-activated human plasmin gave significant lysis but bolus doses of SK. plasmin complex were ineffective. Active site anisoylated derivatives of SK. plasminogen complex, SK-activated plasmin and activator-free plasmin were all active when given as bolus doses in both models. At lytic doses, the acyl-enzymes caused fewer side-effects attributable to plasminaemia than the corresponding unmodified enzymes.

Synthesis and In Vivo Antimalarial Activity of Novel Derivatives of 6- Mercaptopurine

2013 ◽  
Vol 10 (8) ◽  
pp. 741-747 ◽  
Author(s):  
Roberta Soares ◽  
Roberta Corrales ◽  
Fernanda Lopes ◽  
Marcio Alves ◽  
Adilson Silva ◽  
...  
Keyword(s):  
Antimalarial Activity ◽  
Derivatives Of

Derivatives of Deoxypodophyllotoxin Induce Apoptosis Through Bcl-2/Bax Proteins Expression

2020 ◽  
Vol 20 ◽  
Author(s):  
Ya-Nan Li ◽  
Ni Ning ◽  
Lei Song ◽  
Yun Geng ◽  
Jun-Ting Fan ◽  
...  
Keyword(s):  
Annexin V ◽  
Mtt Method ◽  
Anthriscus Sylvestris ◽  
Anti Tumor Activity ◽  
Derivatives Of ◽  
Toxicity In Vitro ◽  
Ht 29 ◽  
Mcf 7

Background: Deoxypodophyllotoxin, isolated from theTraditional Chinese Medicine Anthriscus sylvestris, is well-known because of its significant antitumor activity with strong toxicity in vitro and in vivo. Objective: In this article, we synthesized a series of deoxypodophyllotoxin derivatives, and evaluated their antitumor effectiveness.Methods:The anti tumor activity of deoxypodophyllotoxin derivatives was investigated by the MTT method. Apoptosis percentage was measured by flow cytometer analysis using Annexin-V-FITC. Results: The derivatives revealed obvious cytotoxicity in the MTT assay by decreasing the number of late cancer cells. The decrease of Bcl-2/Bax could be observed in MCF-7, HepG2, HT-29 andMG-63 using Annexin V-FITC. The ratio of Bcl-2/Bax in the administration group was decreased, which was determined by the ELISA kit. Conclusion: The derivatives of deoxypodophyllotoxin could induce apoptosis in tumor cell lines by influencing Bcl-2/Bax.

Some 1-substitution derivatives of 4-aryl-2,3-dihalogeno-1-naphthols

1984 ◽  
Vol 49 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Jiří Křepelka ◽  
Drahuše Vlčková ◽  
Milan Mělka
Keyword(s):  
Thionyl Chloride ◽  
Oxirane Ring ◽  
Secondary Amines ◽  
Two Phase ◽  
Lytic Effect ◽  
Primary And Secondary Amines ◽  
Phase Medium ◽  
Chloro Derivatives ◽  
Derivatives Of

Alkylation of derivatives of 4-aryl-1-naphthols (I-V) by 2,3-epoxypropyl chloride in methanolic sodium hydroxide gave epoxy derivatives VI, VIII, IX, XI and XII, apart from products of cleavage of the oxirane ring, VII and X. Analogous alkylation of compounds I, IV and V by 2-(N,N-diethylamino)ethyl chloride hydrochloride in a two-phase medium afforded basic ethers XIII to XV. The cleavage of the oxirane ring in compound VI by the action of primary and secondary amines, piperidine and substituted piperazines led to compounds XVI-XXIV. Reaction of thionyl chloride with compounds XXI, XXII and XXIV gave chloro derivatives XXV-XXVII.Exposure of compound XXII to 4-methylbenzenesulfonyl chloride produced compound XXVIII, retaining the secondary alcoholic group. In an antineoplastic screening in vivo none of the compounds prepared had an appreciable activity. Compound XVII, being an analogue of propranolol, was used in the test of isoproterenolic tachycardia, and showed a beta-lytic effect comparable with that of propranol.

scholarly journals Subcellular Localization and Vesicular Structures of Anthocyanin Pigmentation by Fluorescence Imaging of Black Rice (Oryza sativa L.) Stigma Protoplast

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 685
Author(s):  
Enerand Mackon ◽  
Yafei Ma ◽  
Guibeline Charlie Jeazet Dongho Epse Mackon ◽  
Qiufeng Li ◽  
Qiong Zhou ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Subcellular Localization ◽  
Oryza Sativa L ◽  
Scientific Evidence ◽  
Brown Rice ◽  
The Body ◽  
Central Vacuole ◽  
In Planta ◽  
Black Rice

Anthocyanins belong to the group of flavonoid compounds broadly distributed in plant species responsible for attractive colors. In black rice (Oryza sativa L.), they are present in the stems, leaves, stigmas, and caryopsis. However, there is still no scientific evidence supporting the existence of compartmentalization and trafficking of anthocyanin inside the cells. In the current study, we took advantage of autofluorescence with anthocyanin’s unique excitation/emission properties to elucidate the subcellular localization of anthocyanin and report on the in planta characterization of anthocyanin prevacuolar vesicles (APV) and anthocyanic vacuolar inclusion (AVI) structure. Protoplasts were isolated from the stigma of black and brown rice and imaging using a confocal microscope. Our result showed the fluorescence displaying magenta color in purple stigma and no fluorescence in white stigma when excitation was provided by a helium–neon 552 nm and emission long pass 610–670 nm laser. The fluorescence was distributed throughout the cell, mainly in the central vacuole. Fluorescent images revealed two pools of anthocyanin inside the cells. The diffuse pools were largely found inside the vacuole lumen, while the body structures could be observed mostly inside the cytoplasm (APV) and slightly inside the vacuole (AVI) with different shapes, sizes, and color intensity. Based on their sizes, AVI could be grouped into small (Ф < 0.5 um), middle (Ф between 0.5 and 1 um), and large size (Ф > 1 um). Together, these results provided evidence about the sequestration and trafficking of anthocyanin from the cytoplasm to the central vacuole and the existence of different transport mechanisms of anthocyanin. Our results suggest that stigma cells are an excellent system for in vivo studying of anthocyanin in rice and provide a good foundation for understanding anthocyanin metabolism in plants, sequestration, and trafficking in black rice.

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