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1.
Salvia divinorum is a plant material that is of forensic interest due to the hallucinogenic nature of the active ingredient, salvinorin A. In this study, S. divinorum was extracted and spiked onto four different plant materials (S. divinorum, Salvia officinalis, Cannabis sativa, and Nicotiana tabacum) to simulate an adulterated sample that might be encountered in a forensic laboratory. The adulterated samples were extracted and analyzed by gas chromatography–mass spectrometry, and the resulting total ion chromatograms were subjected to a series of pretreatment procedures that were used to minimize non-chemical sources of variance in the data set. The data were then analyzed using principal components analysis (PCA) to investigate association of the adulterated extracts to unadulterated S. divinorum. While association was possible based on visual assessment of the PCA scores plot, additional procedures including Euclidean distance measurement, hierarchical cluster analysis, Student’s t tests, Wilcoxon rank-sum tests, and Pearson product moment correlation were also applied to the PCA scores to provide a statistical evaluation of the association observed. The advantages and limitations of each statistical procedure in a forensic context were compared and are presented herein.  相似文献   

2.
Transglutaminase (TGase) is a multifunctional enzyme vital for many physiologic processes, such as cell differentiation, tissue regeneration, and plant pathogenicity. The acyl transfer function of the enzyme can activate primary amines and, consequently, attach them onto a peptidyl glutamine, a reaction important for various in vivo and in vitro protein crosslinking and modification processes. To understand better the structure-function relationship of the enzyme and to develop it further as an industrial biocatalyst, we studied TGase secreted by several Streptomyces species and Phytophthora cactorum. We purified the enzyme from S. lydicus, S. platensis, S. nigrescens, S. cinnamoneus, and S. hachijoensis. The pH and temperature profiles of S. lydicus, S. platensis, and S. nigrescens TGases were determined. The specificity of S. lydicus TGase toward its acyl-accepting amine substrates was characterized. Correlation of the electronic and steric features of the substrates with their reactivity supported the mechanism previously proposed for Streptomyces mobaraensis TGase.  相似文献   

3.
Fucoidans were isolated by water extraction and ion-exchange chromatography from brown algae Eclonia cava, Sargassum hornery, and Costaria costata collected near of Korean coasts. The structures of fucoidans were investigated. Fucoidan from E. cava was mixture of sulfated rhamnogalactofucan and galactofucan. Fucoidan from C. costata was a sulfated galactofucan. Fucoidan isolated from S. hornery was separated into three fractions: a homofucan sulfate, a homofucan but without sulfate groups, and a sulfated rhamnofucan. The results clearly showed that fucoidans play an inhibitory role in colony formation in human melanoma and colon cancer cells and may be effective antitumor agents.  相似文献   

4.
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.
We have developed new DNA extraction and purification procedures for investigation of mycorrhized seedlings and canned truffles. Use of these procedures on approximately 100 mg initial material enabled good sample representation. For mycorrhized seedlings, Taq polymerase inhibitors were discarded irrespective of tree species. In routine analysis we systematically used consensus primers ITS1/ITS4 to check the absence of Taq polymerase inhibitors and the presence of fungus DNA. Positive response with ITS validates other positive or negative PCR results. Absence of amplification with ITS prevents validation of other results. For canned truffles, DNA harvested from ascocarps sterilized for one and a half hours at 115°C was amplified with specific primers. We have developed consensus primers, named R12/F12, to check for the presence of amplifiable fungus DNA and the absence of Taq polymerase inhibitors. Here also, positive response with consensus R12/F12 validates other positive or negative PCR results. We have developed one primer pair specific for T. brumale and another specific for T. melanosporum. We can then characterize these two taxa, which enables the use of truffle or truffled French designations. We can also characterize T. indicum, the Asiatic black truffle that might fraudulently be sold as T. melanosporum and T. brumale. These three specific primer pairs were used independently of DNA extraction from tree seedlings or canned truffles. Our process is specific, sensitive, convenient, and quick.J.P. Douet and D. Mabru have contributed equally to this work  相似文献   

6.

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   

7.
(2S,3S,4S)-2,3-O-Isopropylidene-4-(methoxycarbonylmethyl)cyclopentan-1-one was synthesized starting from D-ribose through methyl (Z)-3-(5-acetyl-2,2-acetoxyacetyl-2,2-dimethyl-1,3-dioxolan-4-yl)prop-2-enoate which was subjected to cyclization in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, followed by decarboxylation.  相似文献   

8.
In the search for platelet-activating-factor (PAF) antagonists, two new lignan compounds were isolated from the leaves of Syringa reticulata Hara var. mandshurica. Their structures were elucidated as (7R,8S, 8'S)-3,4,3',4'-dimethylenedioxy-8,9-dihydroxy-8.8', 7-O-9'-lignan (mandshuricol A) and (7R,8S,8'S)-3',4'methylenedioxy-4-methoxy-3,8,9-trihydroxy-8.8', 7-O-9'-lignan (mandshuricol B), Mandshuricol A and B showed antagonistic activity on PAF in the [3H] PAF receptor binding assay with IC50 values of 4.8 × 10–5 M and 3.5 × 10–5 M, respectively.  相似文献   

9.
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   

10.
In this paper, examination of the aerial parts of seven Senecio species from Serbia and Montenegro is reported. Phytochemical investigation of Senecio erucifolius led to the isolation and characterization of semiquinol butyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (I), along with methyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (jacaranone, II), and methyl 2-(4-hidroxyphenyl)acetate (III). The structure of I was established based on spectroscopic studies (1H- and 13C-NMR, IR, and CI-MS). Compound II was also isolated from S. carpathicus and S. subalpinus. The presence of jacaranone in the methanol extracts of S. wagneri, S. othonnae, and S. paludosus was confirmed by LC/ESI-TOF MS.  相似文献   

11.
Analysis of cellulose biosynthesis using molecular approaches has been successful in identifying genes in many cellulose-producing organisms, yet the mechanism of cellulose biosynthesis still remains to be understood. We are interested in developing the moss Physcomitrella patens as a useful system for the study of cellulose biosynthesis. This moss affords a number of advantages including a haploid dominated gametophyte and a very high efficiency of homologous recombination in its nuclear DNA for constructing gene knockouts. In addition, P. patens has only a primary cell wall unlike Arabidopsis thaliana, which has both a primary and a secondary cell wall. We identified two full-length cellulose synthase (CesA) genes of P. patens, PpCesA6 and PpCesA7 from an EST database and have analyzed the genomic sequences. PpCesA6 and PpCesA7 show high similarity to each other, both at the cDNA and genomic DNA levels. Single and double knockouts of PpCesA6 and PpCesA7 were generated and screened for phenotypic changes. While the PpCesA6 and PpCesA7 single knockouts did not show any obvious phenotypic differences from the wild-type, the double knockout had significantly reduced stem length. These results suggest that PpCesA6 and PpCesA7 probably have a very similar role in cellulose biosynthesis and their functions may be redundant. Additionally, their roles may overlap with the other P. patens CesAs as observed for CesAs involved in primary cell wall biosynthesis in A. thaliana.  相似文献   

12.
We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria–Bertani broth media up to OD600 nm = 0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min.  相似文献   

13.
A new synthetic scheme for 5Z,9E-tridecadien-1-ylacetate, an attractant of the cabbage looper Trichoplusia ni (Huebner) was developed using a highly stereoselective Claisen rearrangement.  相似文献   

14.
The electron impact mass spectra were recorded and the key directions of fragmentation of the highly toxic O-alkyl N,N-dialkylamidocyanophosphates were identified. The sets of characteristic ions for the 10 subgroups of the main group of this class were determined. Based on the values of the mass numbers and peak intensities of characteristic ions generalized spectral images for each of the 10 studied subgroups of this class were simulated. A new method of group identification of O-alkyl N,N-dialkylamidocyanophosphates was developed.  相似文献   

15.
l-Asparaginase (ASNase) has proved its use in medical and food industries. Sequence-based screening showed the thermophilic Streptomyces strain Streptomyces thermoluteus subsp. fuscus NBRC 14270 (14270 ASNase) to positive against predicted ASNase primary sequences. The 14270 ASNase gene and four l-asparaginase genes from Streptomyces coelicolor, Streptomyces avermitilis, and Streptomyces griseus (SGR ASNase) were expressed in Streptomyces lividans using a hyperexpression vector: pTONA5a. Among those genes, only 14270 ASNase and SGR ASNase were successful for overexpression and detected in culture supernatants without an artificial signal peptide. Comparison of the two Streptomyces enzymes described above demonstrated that 14270 ASNase was superior to SGR ASNase in terms of optimum temperature, thermal stability, and pH stability.  相似文献   

16.
In neutral zinc the 4p 2 configuration lies above the 3d 104s ionization limit and its levels become perturbers in the continuum. Lines have been identified in the Zn I spectrum for the multiplet, whereas no lines have been found for transitions to 4p 2 1 D or 1 S. In this paper, cross sections for photoionization from 4s4p levels are reported that reveal the positions and widths of the 4p 2 resonances. Calculations were performed using the multiconfiguration Hartree-Fock (MCHF) and B-spline R-matrix (BSR) method. Results from Breit–Pauli calculations that ignore the background continua are also presented. Included in the latter are energies for the levels and transition data (transition energies, line strengths, f-values, and A-rates) for all E1 transitions between these levels. Transition energies and the agreement in the length and velocity values, particularly for allowed transitions, indicate the accuracy of the computational model. Line widths are compared with other estimates. Contribution to the Serafin Fraga Memorial Issue.  相似文献   

17.
A new cucurbitacin, endecaphyllacin C, was isolated from the tubers of Hemsleya endecaphylla. The structure was elucidated as 2β,16α,20β,25-tetrahydroxy-24-acetylaminocucurbita-5-en-3,11,22-trione (1) on the basis of extensive 1D and 2D NMR techniques, including COSY, HMBC, HMQC, and NOESY correlations, as well as HR-FAB-MS analysis.  相似文献   

18.
Decomposition of a series of N-cyclopropyl-N-nitrosoureas (CNU) in CD3OD was studied. These decompose much more rapidly than N-methyl-N-nitrosourea, one of the decomposition pathways being denitrosation, which is atypical of alkylnitrosoureas under the reaction conditions used. The nature of substituents in the cyclopropane ring has a great effect on the stability of CNU and the product ratio. In the presence of H2 SO4, decomposition occurs much more rapidly. Possible pathways of the formation of the major decomposition products of CNU are proposed based on the experimental data.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 359–370, February, 2005.  相似文献   

19.
A (n, n + 1)-graph G is a connected simple graph with n vertices and n + 1 edges. In this paper, we determine the lower bound for the Hosoya index in (n, n + 1)-graphs in terms of the order n, and characterize the (n, n + 1)-graph with the smallest Hosoya index.  相似文献   

20.
New carbohydrate-containing aminophosphoryl compounds were synthesized on the basis of glycosylamines. The reaction pathway suggested for addition of hydrophosphoryl compounds to N-glycosides was confirmed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1986–1992, September, 2008.  相似文献   

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