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971.
Ondřej Kaplan Alicja B. Veselá Alena Petříčková Fabrizia Pasquarelli Martina Pičmanová Anna Rinágelová Tek Chand Bhalla Miroslav Pátek Ludmila Martínková 《Molecular biotechnology》2013,54(3):996-1003
Escherichia coli strains expressing different nitrilases transformed nitriles or KCN. Six nitrilases (from Aspergillus niger (2), A. oryzae, Neurospora crassa, Arthroderma benhamiae, and Nectria haematococca) were arylacetonitrilases, two enzymes (from A. niger and Penicillium chrysogenum) were cyanide hydratases and the others (from P. chrysogenum, P. marneffei, Gibberella moniliformis, Meyerozyma guilliermondi, Rhodococcus rhodochrous, and R. ruber) preferred (hetero)aromatic nitriles as substrates. Promising nitrilases for the transformation of industrially important substrates were found: the nitrilase from R. ruber for 3-cyanopyridine, 4-cyanopyridine and bromoxynil, the nitrilases from N. crassa and A. niger for (R,S)-mandelonitrile, and the cyanide hydratase from A. niger for KCN and 2-cyanopyridine. 相似文献
972.
Biotransformations using microbial nitrile- and amide-converting enzymes have developed considerably in the recent years. Most processes profited from the stereo-, regio- and chemoselectivity of nitrile hydratases, nitrilases and amidases specific for primary or secondary amides. The aim of this review is to discuss the developments in this branch of biotransformations in the last ca. 5 years by taking highlights from research journals, patents and industrial applications. 相似文献
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974.
975.
Ludmila P. Ponomarenko Anatoly I. Kalinovsky Ekaterina A. Martyyas Roman V. Doudkin Petr G. Gorovoy Valentin A. Stonik 《Phytochemistry letters》2012,5(1):118-122
Six naturally occurring terpenoids were isolated from the hexane extract of rabbit-head wormwood Artemisia lagocephala (Fisch. ex Besser) DC. The terpenoids’ structures were elucidated by spectroscopic and chemical methods as 3β-acetoxycycloartan-24-ozonide (1), 3β-acetoxycycloartan-24-al (2), 25,26,27-trisnor-3β-acetoxycycloartan-24-ol (3), 24,25,26,27-tetranor-3β-acetoxycycloartan-23-ol (4), and the previously known caryophyllene oxide (5) and (1R,4S)-p-menth-2-en-1-ol (6). 相似文献
976.
Monika Sobczak Tomasz Boczek Antoni Kowalski Magdalena Wiktorska Jolanta Niewiarowska Ludmila Zylinska 《Journal of physiology and biochemistry》2014,70(2):375-383
Microsomal glutathione-S-transferase 1 (Mgst1) plays a specific role in protection of cells against oxidative stress. In this study, we assayed the effect of Mgst1 downregulation on cells behavior using differentiated PC12 line, a widely accepted neuronal model system. We have developed stable transfected cells with downregulated Mgst1 (PC12_M), which were differentiated with 1 mM dibutyryl-cAMP (db-cAMP). Mgst1 reduction induced necrosis, decreased ATP amount, and increased thiobarbituric acid reacting substances (TBARS) content. However, in PC12_M cell population, we detected more intensive neuritogenesis than that in mock-transfected cells. Interestingly, total glutathione as well as GSH level were significantly higher than those in control PC12 line. Real-time PCR and Western blot analyses showed elevated expression of enzymes involved in glutathione metabolism—a rate-limiting γ-glutamylcysteine ligase and glutathione reductase. The present study shows for the first time that under stress conditions induced by Mgst1 downregulation, a rescue pathway can be activated and thereby enables differentiated PC12 cells to survive. Since Mgst1expression was reported to decline with age, our results could represent a putative adaptive process during aging. It could also be an early mechanism protecting neuronal cells against some neurodegenerative insults. 相似文献
977.
978.
Ludmila K. Polevaya 《Letters in Peptide Science》1996,3(4):252-256
Summary In this report we describe our own attempt to explain the similarity of some effects of unique endogenous bioregulators such as angiotensin and thrombin at the molecular level. We also briefly review the cellular effects and signalling pathways of these molecules. Recent studies indicate that thrombin displays two opposing vascular effects: endothelium-dependent relaxation and endothelium-independent vasoconstriction. However, it should be noted that this enzyme possesses both vasocontractile and growth-stimulating activities which are similar to those of angiotensin. To examine a molecular basis for the functional duality of thrombin and similarity with angiotensin-induced effects, we analyzed the thrombin sequence and 3D structure. We found that (i) segment 84–135 of thrombin includes two angiotensin-like sites, which contain the repeats of the Tyr-Ile-His-Pro sequence and are identical to the functionally important fragment of angiotensin; and (ii) the thrombin 68–150 domain resembles the C-terminal tail of the macrophage migration inhibitory factor (MIF): five of the eight residues in angiotensin (Asp-Arg-Val-Tyr-Ile) are identical to fragment 94–98 of this one. Thus, angiotensin shares a surprisingly high degree of structural homology with both these molecules. We anticipated that angiotensin-like sites of thrombin (fragments 86–95 and 117–127) might be responsible for its vascular and growth-promoting activities on vascular smooth muscle cells. Taken together, the data obtained from a comparative analysis of thrombin, angiotensin and macrophage migration inhibitory factor-induced effects enable us to reveal the regulatory responsible domain of the enzyme and may prove useful for drug design. 相似文献
979.
Ludmila Martínková Norbert Klempier Irena Prepechalov´ Vera Prikrylová Mária Ovesná Herfried Griengl Vladimír Kren 《Biotechnology letters》1998,20(10):909-912
Resting cells of Rhodococcus equi A4 (free or immobilized in hydrogels) produced monomethyl isophtalate 1c and monomethyl terephtalate 2c from methyl-3-cyanobenzoate 1a and methyl-4-cyanobenzoate 2a, respectively, via the intermediate carboxamides 1b and 2b. The use of dried immobilized biocatalysts resulted in an increased formation of the unwanted cyano acids 1d and 2d. © Rapid Science Ltd. 1998 相似文献
980.
Lise Heginbotham Ludmila Kolmakova-Partensky Christopher Miller 《The Journal of general physiology》1998,111(6):741-749
SliK, a K+ channel encoded by the Streptomyces KcsA gene, was expressed, purified, and reconstituted in liposomes. A concentrative 86Rb+ flux assay was used to assess the ion transport properties of SliK. SliK-mediated ionic flux shows strong selectivity for K+ over Na+ and is inhibited by micromolar concentrations of Ba2+, mirroring the basic permeation characteristic of eukaryotic K+ channels studied by electrophysiological methods. 86Rb+ uptake kinetics and equilibrium measurements also demonstrate that the purified protein is fully active. 相似文献