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1.
T. F. Ibragimov M. G. Levkovich V. A. Saprykina Kh. M. Shakhidoyatov 《Chemistry of Natural Compounds》2010,46(5):767-770
N-Chloroacetylcytisine was synthesized by acylation of (–)-cytisine. Stable Z- and E-conformers with respect to rotational isomerism around the N-12–CO bond were found in PMR spectra at room temperature. The
point at which PMR resonances of the Z- and E-conformers coalesced upon heating was measured. The transition barrier between the conformers was estimated. 相似文献
2.
Peng Huang Jinlei Shi Qingwen Sun Xianping Dong Ning Zhang 《Applied biochemistry and biotechnology》2018,186(2):459-475
Lysozymes are known as ubiquitously distributed immune effectors with hydrolytic activity against peptidoglycan, the major bacterial cell wall polymer, to trigger cell lysis. In the present study, the full-length cDNA sequence of a novel sea urchin Strongylocentrotus purpuratus invertebrate-type lysozyme (sp-iLys) was synthesized according to the codon usage bias of Pichia pastoris and was cloned into a constitutive expression plasmid pPIC9K. The resulting plasmid, pPIC9K-sp-iLys, was integrated into the genome of P. pastoris strain GS115. The bioactive recombinant sp-iLys was successfully secreted into the culture broth by positive transformants. The highest lytic activity of 960 U/mL of culture supernatant was reached in fed-batch fermentation. Using chitin affinity chromatography and gel-filtration chromatography, recombinant sp-iLys was produced with a yield of 94.5 mg/L and purity of >?99%. Recombinant sp-iLys reached its peak lytic activity of 8560 U/mg at pH 6.0 and 30 °C and showed antimicrobial activities against Gram-negative bacteria (Vibrio vulnificus, Vibrio parahemolyticus, and Aeromonas hydrophila) and Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis). In addition, recombinant sp-iLys displayed isopeptidase activity which reached the peak at pH 7.5 and 37 °C with the presence of 0.05 M Na+. In conclusion, this report describes the heterologous expression of recombinant sp-iLys in P. pastoris on a preparative-scale, which possesses lytic activity and isopeptidase activity. This suggests that sp-iLys might play an important role in the innate immunity of S. purpuratus. 相似文献
3.
Reactions of acetamide and benzamide with N-allyltrifluoromethanesulfonamide in the presence of t-BuOCl–NaI afforded exclusively 2,5-bis(chloromethyl)-1,4-bis(trifluoromethanesulfonyl)piperazine. Analogous reaction with N,N-diallyltrifluoromethanesulfonamide gave mixed halogenation product at only one C=C double bond of the substrate. 相似文献
4.
A. V. Lezov G. E. Polushina A. A. Lezov P. S. Vlasov N. S. Domnina 《Polymer Science Series A》2011,53(2):93-101
The hydrodynamic and conformational properties of molecules of poly(N,N-diallyl-N,N-dimethylammonium chloride) and N,N-diallyl-N,N-dimethylammonium chloride-maleic acid copolymers of different compositions in solutions with various ionic-strength and pH
values, as well as of the polyelectrolyte complex based on the copolymer with dodecyl sulfate anions in chloroform, are studied.
For poly(N,N-diallyl-N,N-dimethylammonium chloride) molecules in a 1 M NaCl solution, the Kuhn segment length and the hydrodynamic diameter of the
chain are estimated as A = 3.9 nm and d = 0.48 nm, respectively. In acidic solutions with pH 3.5, the copolymers demonstrate behavior typical for polyelectrolytes.
In an alkaline solution with pH 13, when 1 M NaCl is added to the solution of the copolymer containing 29 mol % maleic acid
units, there is an antipolyelectrolyte effect that manifests itself as an increase in the intrinsic viscosity of the copolymer
and in the hydrodynamic radius of its molecules. It is found that an increase in the fraction of maleic acid units in the
copolymer from 12 to 42 mol % brings about a reduction in the equilibrium rigidity of its macromolecules from 4.1 to 2.2 nm.
The equilibrium rigidity of polyelectrolyte-complex molecules is higher than that of initial copolymer molecules owing to
steric interactions arising between the aliphatic chains of dodecyl sulfate anions. In an electric field, the molecules of
the complex are oriented owing to the induced dipole moment resulting from the displacement of dodecyl sulfate anions along
the chain contour. 相似文献
5.
Corncob is an economic feedstock and more than 20 million tons of corncobs are produced annually in China. Abundant xylose
can be potentially converted from the large amount of hemicellulosic materials in corncobs, which makes the crop residue an
attractive alternative substrate for a value-added production of a variety of bioproducts. Lactic acid can be used as a precursor
for poly-lactic acid production. Although current industrial lactic acid is produced by lactic acid bacteria using enriched
medium, production by Rhizopus oryzae is preferred due to its exclusive formation of the l-isomer and a simple nutrition requirement by the fungus. Production of l-(+)-lactic acid by R. oryzae using xylose has been reported; however, its yield and conversion rate are poor compared with that of using glucose. In this
study, we report an adapted R. oryzae strain HZS6 that significantly improved efficiency of substrate utilization and enhanced production of l-(+)-lactic acid from corncob hydrolysate. It increased l-(+)-lactic acid final concentration, yield, and volumetric productivity more than twofold compared with its parental strain.
The optimized growth and fermentation conditions for Strain HZS6 were defined. 相似文献
6.
7.
A. I. Vorob’eva M. S. Babaev L. V. Spirikhin N. M. Shishlov S. V. Kolesov 《Russian Journal of Applied Chemistry》2016,89(1):160-164
A copolymer of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid of constant composition was prepared under the conditions of radical initiation. The possibility of the functionalization of the copolymer with drugs containing amino groups by polymer-analogous transformations was examined. Conditions were found for preparing conjugates of the copolymer with isoniazid. The structures and the quantitative compositions of the conjugates were determined by 13С NMR spectroscopy, and the possibility of preparing conjugates with controlled drug content was demonstrated. 相似文献
8.
9.
Eberhard Reimann Rainer Hertel Jürgen Krauss 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):673-684
Alkylation of Reissert compounds derived from 3-methylisoquinolines with several 2-cyanobenzylbromides followed by hydrolytic cleavage provided the corresponding 1-benzyl-3-methylisoquinolines. Treatment of the latter with methylmagnesiumiodide caused cyclization to the title compounds rather than formation of 2-acetylbenzylisoquinolines. 相似文献
10.
Background
Adenylation of nicotinate mononucleotide to nicotinate adenine dinucleotide is the penultimate step in NAD+ synthesis. In Escherichia coli, the enzyme nicotinate mononucleotide adenylyltransferase is encoded by the nadD gene. We have earlier made an initial characterization in vivo of two mutant enzymes, NadD72 and NadD74. Strains with either mutation have decreased intracellular levels of NAD+, especially for one of the alleles, nadD72. 相似文献11.
O. G. Strukov V. B. Kondrat’ev Z. V. Vlasova V. A. Petrunin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(1):100-105
Conformers of the biologically active compounds CH3P(O)(OR)(SCH2CH2NR 2 ′ ), where (I) R = i-C4H9, R′ = C2H5 and (II) R = C2H5, R′ = i-C3H7, are calculated within the AM1 level of theory. The elongated and twisted forms with maximum and minimum distances between a nitrogen atom and those of a phosphorus tetrahedron, respectively, and bearing a syn and anti oriented alkoxy group relative to a phosphoryl oxygen, are studied. It is found that the differences between the energy, electronic, and geometric parameters of these forms are apparent in differences between their properties, e.g., the ability to participate in complexation and protonation, reactions that to some extent simulate the interaction between a substance and a biological object. 相似文献
12.
Due to great interest on producing bioactive compounds for functional foods and biopharmaceuticals, it is important to explore the microbial degradation of potential sources of target biomolecules. Gallotannins are polyphenols present in nature, an example of them is tannic acid which is susceptible to enzymatic hydrolysis. This hydrolysis is performed by tannase or tannin acyl hydrolase, releasing in this way, biomolecules with high-added value. In the present study, chemical profiles obtained after fungal degradation of tannic acid under two bioprocesses (submerged fermentation (SmF) and solid state fermentation (SSF)) were determined. In both fermentation systems (SmF and SSF), Aspergillus niger GH1 strain and tannic acid as a sole carbon source and inducer were used (the presence of tannic acid promotes production of enzyme tannase). In case of SSF, polyurethane foam (PUF) was used like as support of fermentation; culture medium only was used in case of submerged fermentation. Fermentation processes were monitored during 72 h; samples were taken kinetically every 8 h; and all extracts obtained were partially purified to obtain polyphenolic fraction and then were analyzed by liquid chromatography-mass spectrometry (LC-MS). Molecules like gallic acid and n-galloyl glucose were identified as intermediates in degradation of tannic acid; during SSF was identified ellagic acid production. The results obtained in this study will contribute to biotechnological production of ellagic acid. 相似文献
13.
U. S. Makhmudov Sh. B. Rakhimov B. Tashkhodzhaev M. G. Levkovich V. I. Vinogradova 《Chemistry of Natural Compounds》2008,44(2):208-212
The molecular structures of N-(o-and p-hydroxybenzyl)cytisine were investigated by NMR spectroscopy, x-ray structure analysis, and molecular modeling. It was found
that NMR resonances of the OH and aromatic protons in N-(o-hydroxybenzyl)cytisine were doubled because of the presence of two conformers in solution.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 165–168, March–April, 2008. 相似文献
14.
Sivachandiran Somasundaram Gyeong Tae Eom Soon Ho Hong 《Applied biochemistry and biotechnology》2018,184(4):1308-1318
Recently, malic acid has gained attention due to its potential application in food, pharmaceutical, and medical industries. In this study, the synthetic scaffold complex strategy was employed between the two key enzymes pyruvate kinase (PykF) and malic enzyme (SfcA); SH3 ligand was attached to PykF, and the SH3 domain was attached to the C-terminus of ScfA. Synthetic scaffold systems can organize enzymes spatially and temporally to increase the local concentration of intermediates. In a flask culture, the recombinant strain harboring scaffold complex produced a maximum concentration of 5.72 g/L malic acid from 10 g/L glucose. The malic acid production was significantly increased 2.1-fold from the initial culture period. Finally, malic acid production was elevated to 30.2 g in a 5 L bioreactor from recombinant strain XL-1 blue. 相似文献
15.
The marine yeast strain Kodamea ohmeri BG3 isolated from the gut of a marine fish (Hexagrammes otakii) was found to secrete a large amount of phytase into the medium. The crude phytase produced by this marine yeast showed the
highest activity at pH 5.0 and 65 °C. The optimal medium for phytase production contained oat 10.0 g/l, ammonium sulfate 15.0 g/l,
glucose 30 g/l, and NaCl 20.0 g/l, while the optimal cultivation conditions for phytase production were pH 5.0, a temperature
of 28 °C, and a shaking speed of 170 rpm. Under the optimal conditions, over 557.9 mU/ml of phytase activity was produced
within 72 h of fermentation at the shake flask level. This is a very high level of phytase activity produced by yeasts. We
think that the medium and process for phytase production by the marine yeast strain were very simple, and such marine yeast
from the gut of natural marine fish may have a potential application in the maricultural industry and marine environmental
protection. The results demonstrate that phytate was actively degraded by the crude phytase within a short period. 相似文献
16.
Watanapokasin R Sawasjirakij N Usami S Kirimura K 《Applied biochemistry and biotechnology》2007,143(2):176-186
The first-stage heterokaryons, obtaining from intergeneric protoplast fusion between Aspergillus niger (Y-b) and Trichoderma viride (M5S51), showed slow growth and mixed morphologies on minimal medium. The fusants were classified into heterokaryon and prototrophic haploid, showing the morphology as that of A. niger. The heterokaryon strains formed conidia with the same nutritional requirements as those of the original auxotrophic mutant strains. After several subcultivations on minimal medium containing d-camphor, some heterokaryon strains formed larger two to seven nuclei/conidium as compared to one nucleus/conidium of the auxotrophic mutant and prototrophic strains, indicating that the new hybrids were generated. Interestingly, three fusant strains AT 11-2-3, AT 11-2-10, and AT 11-2-14 produce 19.2, 6.1, and 10.5 g/l citric acid, respectively, in semisolid culture containing cellulose, whereas A. niger Yang no. 2 could not use carboxymethyl cellulose as the sole carbon source for citric acid production. In addition, the average maximum beta-glucosidase and carboxymethylcellulase productions from AT 11-2-3, AT 11-2-10, and AT 11-2-14 were about 16- and 4-folds higher than those of A. niger, respectively. 相似文献
17.
D. T. Asilbekova F. M. Tursunkhodzhaeva A. M. Nigmatullaev 《Chemistry of Natural Compounds》2009,45(3):322-324
The composition of lipids from the aerial parts of two species of halophytes from the family Chenopodiaceae, Halostachys caspica C. A. Mey. and Halocharis hispida Bge. was determined. Neutral lipids (NL, 62.1 and 54.2%, respectively) dominated the total lipids (TL) of these plants. More
than a third of the NL were esters of aliphatic alcohols and phytosterols (FAE). Fatty acids 16:0, 18:1, and 18:2 dominated
the acids of FAE; 16:0, 18:1, and 18:3, the phospholipids. The principal fatty acids of glycolipids were unsaturated acids
(68.3 and 75.1%) with linolenic acid dominating (44.9 and 43.5%).
Presented at the 7th International Symposium on the Chemistry of Natural Compounds, Tashkent, October 16–18, 2007.
Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 276–278, May–June, 2009. 相似文献
18.
19.
The 5-aminolevulinate (ALA) synthase gene (hemA) from Agrobacterium radiobacter zju-0121, which was cloned previously in our laboratory, contains several rare codons. To enhance the expression of this
gene, Escherichia coli Rosetta(DE3), which is a rare codon optimizer strain, was picked out as the host to construct an efficient recombinant strain.
Cell extracts of the recombinant E. coli were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under the appropriate conditions. The results
indicated that the activity of ALA synthase expressed in Rosetta(DE3)/pET-28a(+)-hemA was about 20% higher than that in E. coli BL21(DE3). Then the effects of precursors (glycine and succinate) and glucose, which is an inhibitor for ALA dehydratase
as well as the carbon sources for cell growth, on the production of 5-aminolevulinate were investigated. Based on an optimal
fed-batch culture system described in our previous work, up to 6.5 g/l (50 mM) ALA was produced in a 15-l fermenter. 相似文献
20.
P. A. Storozhenko Z. V. Belyakova O. A. Starikova V. M. Nosova T. I. Shulyat’eva A. S. Frenkel’ M. V. Pecherskii 《Russian Journal of General Chemistry》2008,78(5):892-897
N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and 1H, 13C, and 29Si NMR spectroscopy. 相似文献