排序方式: 共有8条查询结果,搜索用时 31 毫秒
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Aglika Edreva Violeta Sotirova Iordanka D. Georgieva Elisaveta Stoimenova Rositza Rodeva Nevena Bogatzevska 《Acta Physiologiae Plantarum》2000,22(3):274-277
In the present work the responses of β-glucosidase in leaves of tomato plants subjected to various stress factors of both
pathogenic (fungi, bacteria, viruses) and abiotic origin (heat shock) were studied. Biochemical and cytochemical methods were
applied. It was established that an increase of β-glucosidase activity is induced uniquely by fungal pathogens. The cytochemical
tests confirm the finding. Hence, the conclusion can be drawn that β-glucosidase response is a specific character of fungal
pathogenesis in tomato; probably, the enzyme is involved in plant — fungi recognition. The data are in accordance with our
previous results on tobacco and wheat — stress stimuli systems. 相似文献
2.
New series of N-modified analogues of the N/OFQ(1-13)NH(2) with aminophosphonate moiety have been synthesized and investigated for biological activity. These peptides were prepared by solid-phase peptide synthesis-Fmoc-strategy. The N/OFQ(1-13)NH(2) analogues were tested for agonistic activity in vitro on electrically stimulated rat vas deferens smooth-muscle preparations isolated from Wistar albino rats. Our study has shown that the selectivity of the peptides containing 1-[(methoxyphosphono)methylamino]cycloalkanecarboxylic acids to the N-side of Phe is not changed-they remain selective agonists of NOP receptors. The derivative with the largest ring (NOC-6) demonstrated efficacy similar to that of N/OFQ(1-13)NH(2), but in a 10-fold higher concentration. The agonistic activity of newly synthesized N-modified analogues of N/OFQ(1-13)NH(2) with aminophosphonate moiety was investigated for the first time. 相似文献
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Dorkov P Pantcheva IN Sheldrick WS Mayer-Figge H Petrova R Mitewa M 《Journal of inorganic biochemistry》2008,102(1):26-32
Mononuclear neutral manganese(II) and cobalt(II) complexes with the antibiotic Sodium Monensin A (Mon-Na, 1b) were synthesized and characterized. The crystal structures of M(Mon-Na)2Cl2.H2O (M=Mn, 2; M=Co, 3) were determined by X-ray crystallography. The complexes crystallize in monoclinic space group C2 with a tetrahedrally coordinated transition metal attached to oxygen atoms of deprotonated carboxyl groups of two Sodium Monensin molecules and two chloride ions. The sodium ion remains in the cavity of the ligand and cannot be replaced by Mn(II) or Co(II). The complexes were additionally characterized by different spectroscopic techniques (UV-Visible, EPR, FAB-MS). A preferable octahedral environment around the transition metal centers is observed in polar solvents while the complexes retain their tetrahedral structure in non-polar media. The antimicrobial activity of 1b, 2 and 3 was tested against Gram(+) and Gram(-) bacteria. 相似文献
4.
Naydenova ED Zhivkova VI Zamfirova RN Vezenkov LT Dobrinova YG Mateeva PI 《Bioorganic & medicinal chemistry letters》2006,16(15):4071-4074
The purpose of the present study was the synthesis and the biological screening of new analogues of N/OFQ(1-13)NH2, the minimal sequence maintaining the same activity as the natural peptide nociceptin. In order to investigate the role of Lys, we substituted Lys at positions 9 and/or 13 by Orn, Dab (diaminobutanoic acid) or Dap (diaminopropanoic acid). The new N/OFQ(1-13)NH2 analogues exerted strong and naloxone-resistant inhibition of electrically evoked contractions of rat vas deferens. Lys replacement with Orn maintained or even enhanced the inhibitory activity, while replacements with Dab and Dap decreased inhibitory activity. 相似文献
5.
The xylanase biosynthesis is induced by its substrate - xylan. The high xylan content in some of the wastes like corn cobs and wheat bran makes them an accessible and cheap source of inducers. Nutrient medium for xylanase biosynthesis in submerged cultivation of Aspergillus niger B03 has been optimized. The optimization process was analyzed using optimal composite experimental design and response surface methodology. The predicted by the regression model optimum components of nutrient medium are as follows (g/l): (NH(4))(2)HPO(4) 2.6, urea 0.9, corn cobs 24.0, wheat bran 14.6 and malt sprout 6.0. Five parallel experiments have been carried out, at definite, optimum components concentrations of the nutrient medium, and a mean value of the activity Y=996.30 U/ml has been obtained. The xylanase activity, obtained with the optimized nutrient medium is 33% higher than the activity, achieved with the basic medium. 相似文献
6.
Stoeva Pravda Yankulova Margarita Nikolaeva Velichka Bachvarova Rositza Ivanova Lidia Maiss Edgar Adam Guenter Vulkov Vladimir Guelemerov Spas Atanassov Atanas 《Molecular breeding : new strategies in plant improvement》1998,4(2):155-164
We examined the resistance phenotype of a large number of transgenic tobacco plants originating from 12 commercial (Nicotiana tabacum) cultivars expressing the sense form of the nucleoprotein (N) gene of L3, a Bulgarian isolate of tomato spotted wilt virus (TSWV). The analysis revealed that transgenic plants are completely protected against the homologous L3 isolate of TSWV irrespective of whether or not they contain detectable levels of translational product. The effectiveness of protection against the virus was investigated upon mechanical inoculation under greenhouse conditions and in field trials. Non-segregating resistant lines were selected and the inheritance of the resistance to TSWV was analysed in successive generations (R3–R6). Extensive tests under controlled conditions and two-year field trials proved that the resistance to TSWV is stable in different environments and is a stably inherited trait. 相似文献
7.
Vircheva S Alexandrova A Georgieva A Mateeva P Zamfirova R Kubera M Kirkova M 《Cell biochemistry and function》2010,28(8):668-672
The present study aimed to investigate the effects of pentoxifylline (PTX) on the carrageenan (CG)-induced paw oedema and on the endogenous levels of cell enzyme and non-enzyme antioxidants in rat liver, 4 and 24 h after CG injection. PTX (50 mg kg(-1) , i.p.), administered 30 min before CG, decreased the paw oedema, 2-4 h after CG administration. The drug protected CG-induced decrease of glutathione (non-enzyme antioxidant) and had no effect on CG-unchanged activities of superoxide dismutase, glutathione peroxidase (enzyme antioxidants) and glucose-6-phosphate dehydrogenase (enzyme, important for the activity of GSH-conjugated antioxidant enzymes). The drug showed a good antioxidant capacity in chemical systems, generating reactive oxygen species. The present results suggest that the antioxidant activity of PTX might contribute to its beneficial effects in liver injuries. 相似文献
8.
Emilia D. Naydenova Petar T. Todorov Polina I. Mateeva Rositza N. Zamfirova Nikola D. Pavlov Simeon B. Todorov 《Amino acids》2010,39(5):1537-1543
The aim of the present study was the synthesis and the biological screening of new analogs of Ac-RYYRWK-NH2, modified at the N-terminal with 1-[(methoxyphosphono)methylamino]cycloalkanecarboxylic acids. The four newly synthesized
ligands for the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) have been prepared by solid-phase peptide synthesis—Fmoc-strategy.
These compounds were tested for agonistic activity in vitro on electrically stimulated smooth-muscle preparations isolated
from vas deferens of Wistar rats. Our data showed that substitution of Arg at position 1 with aminophosphonates moiety decreased
significantly the affinity of ligands to the NOP receptor. Furthermore, the enlargement of the cycle (with 5–8 carbon atoms)
additionally diminished both the activity and the selectivity for NOP-receptor. 相似文献
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