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1.
Water-soluble polysaccharides have been isolated from two species ofEremurus — E. lactiflorus andE. luteus — with yields of 13.5% and 20.5%, respectively. They contained mainly glucose and mannose in ratios of 1:5 and 1:3.1. The polysaccharides ofE. lactiflorus were separated from a column of DEAE-cellulose. The yield of neutral fraction was 10.3%. Gel filtration of the polysaccharides on Sephadex G-200 showed their polydispersity. Homogeneous fractions were obtained by fractional precipitation with ethanol. They have been characterized with respect to monosaccharide composition, molecular weight, and IR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 604–608, September–October, 1979.  相似文献   

2.
Ten oligosaccharides have been isolated from the products of the partial hydrolysis of a native acetylated glucomannan obtained fromEremurus lactiflorus O. Fedtsch. Their structures have been studied with the aid of acid hydrolysis before and after reduction with NaBH4, by the GLC method, and also by chromatography with markers. The compositions and sequence of the monomers in tetra- and heptaoligo-saccharides have been determined by the13C NMR method. The glucommannan ofE. lactiflorus differs from theEremurus glucomannans studied previously by the ratio of monosaccharides, the presence of 0-Ac groups, the degree of polymerization, and the presence of a cellobiose unit (Glcp-Glcp) in the polymer chain. The repeating unit consists of 14 hexose residues.  相似文献   

3.
The13C spectra of the glucomannans fromEremurus lactiflorus andE. luteus are analyzed in comparison with the spectra of low-molecular-weight model compounds. It has been shown that the linear polymer chain consists of 1 → 4-bound glycosidic residues in the pyranose form, which confirms the results of earlier chemical investigations of these polysaccharides.  相似文献   

4.
It has been established by oxidation with chromium trioxide and sodium periodate and by methylation that the monosaccharide residues in the glucomannan ofEremurus lactiflorus O. Fed. are linked by β-1 →; 4 bonds, and there is a mannose residue at the nonreducing end. The glucomannan macromolecule has a linear structure.  相似文献   

5.
A new aporphine base — baicaline — has been isolated from the epigeal part ofThalictrum baicalense. Its structure has been established as 1,9,10-trimethoxy-2,3-methylenedioxynoraporphine. Magnoflorine and berberine have been isolated from the roots of the plant.  相似文献   

6.
A physicochemical and complete x-ray structural investigation of the new alkaloid severidine isolated from the epigeal part ofKorolkowia sewerzowii Regel has been performed. The crystals were investigated in the form of severidine hydrochloride, C27H43NO5·HCl, rhombic,a=12.642, b=12.882, c=16.621 Å, z=4, space group P212221, at ?120°C. The structure was interpreted by the direct method and was refined to R=0.039. The hydrogen atoms were revealed. The absolute configuration was established by means of the Hamilton test. The skeleton of the cation is constructed of bicyclic and tricyclic fragments linked by an ordinary C-C bond. All the rings have the chair conformation. The bond lengths and valence angles are normal.  相似文献   

7.
We have measured the ratio of cross sections σ(KL 2,3)/σ(K) for neon for electron impact in the energy range ofE 0=1.5 ... 50 keV via the intensity ofKL 2,3?LLL 2,3 Auger satellite lines relative to the intensity ofKL 1 L 2,3 (3 P) diagram line. The experimental ratio decreases over the full range of energyE 0 which is contrary to an earlier result by Carlson et al. We have also measured the alignment ofKL 2,3 1 P and3 P states via the angular distribution of Auger satellite intensity for the energy rangeE 0=1.5 ... 4 keV, within experimental error we have found a zero alignment. The totalK Auger spectrum, measured forE 0=40 keV and at the magic angle of emission ?=54.7°, has been decomposed into its components by using appropriate line shapes distorted by postcollision interaction. Finally, we discussed whether the lines observed at the high-energy side ofKL 2,3?LLL 2,3 Auger satellite lines can be interpreted as structures caused by an angular momentum exchange in the postcollision interaction predicted by Niehaus and Zwakhals.  相似文献   

8.
From the WSPS-I of the bulbs with roots ofJuno drepanophylla, 15 fractions have been isolated by fractionation on DEAE-cellulose. Fractions 1 and 2 together made up 53% of the total weight of the fractions. Fraction 1 proved to be homogeneous on ultracentrifugation, on passage through Sepharose-4B, and on high-pressure LC. The results of the analysis of the methylated product of fraction 1 differed little from those for the initial polysaccharide.  相似文献   

9.
A new affinity sorbent has been synthesized — soybean trypsin inhibitor (STI)-amylopectin-hydrazidosuccinyl-Sepharose — and its properties have been studied in comparison with those of an analogous adsorbent without the spacer STI-Sepharose. The STI-amylopectin-hydrazidosuccinyl-Sepharose adsorbent has been used for the purification of trypsin from porcine pancreas and of callicrein from human blood plasma.  相似文献   

10.
Complexation of uranyl(II) and beryllium(II) ions with 2,2′-dimercaptodiethyl ether has been studied in 40% ethanolic media by potentiometric and conductometric titration techniques revealing the formation of an 1∶1 complex in either case. The stability constants of the complexes have been determined at ionic strength μ=0.1M (NaClO4) by applyingCalvin andMelchior's extension ofBjerrum's method. LogK stab values are found to be 12.60, 11.96 at 25 °C and 12.55, 11.90 at 35 °C respectively. The values of ΔG, ΔH and ΔS for the complexation reactions determined at 25 °C are also reported.  相似文献   

11.
The kinetics of HCl oxidation at 350–425°C over a (CuCl2-KCl)/support catalyst in two complementary processes—Deacon and methane oxychlorination reactions—has been investigated using a gradientless technique. This has allowed the range of \(P_{Cl_2 }\) in the reaction mixture to be markedly extended. New kinetic features of HCl oxidation under conditions such that this process does and does not depend on P HCl have been discovered. The kinetic equations obtained in this study fit experimental data in a wider range of conditions than the equations proposed earlier. The results of this study suggest the existence of two HCl oxidation pathways in the Deacon reaction.  相似文献   

12.
Photoionization experiments have been performed to investigate Ne clusters after absorbing a single photon of known energy. The photon energies used were below the threshold energy of the Ne atom. Masses and initial velocities of the clusters were determined by time-of-flight techniques with a resolution ofmm ≈ 500 (tt ≈ 1000). The mass spectra of Ne clusters differ significantly from those reported for other rare gas clusters. An analysis of the isotopic composition of the clusters showed an enrichment of22Ne, which is attributed to a photo-induced fragmentation process.  相似文献   

13.
Quantitative determination revealed the presence of storage glucan (6.0%), fucoidan (19.2%) and alginate (12.7%) in the biomass of the brown alga Punctaria plantaginea collected from the Sea of Japan. The polysaccharides were isolated from the alga by fractional extraction followed by additional purification procedures. Unlike the well-known laminarans the storage polysaccharide from P. plantaginea was shown to be a linear (1→6)-β-d-glucopyranan, which is new for brown alga. The content of guluronic acid (G) residues in the alginate molecules exceeded the content of mannuronic acid residues (M), M/G = 0.5. Poly-G and poly-MG blocks were isolated from the products of partial hydrolysis of alginic acid; however, a heterogeneous mixture of polysaccharide fragments was obtained instead of the expected poly-M fraction. Preliminary data suggests that fucoidan from this alga is a new for brown algae type of sulfated polysaccharide (xylofucan) with a main backbone built of α-l-fucopyranose residues. This chain contains multiple sulfate groups and single non-sulfated β-d-xylopyranose residues as substituents.  相似文献   

14.
Detection of staphylococcal toxins presents a great interest for medical diagnostics. Screening of clinical samples for the presence of several types of staphylococcal toxins using traditional methods—biological tests on animals or cell cultures as well as ELISA—is laborious. Multiplex detection methods would simplify testing. We have designed an xMAP-based assay to detect three staphylococcal toxins—enterotoxins A and B (SEA and SEB) and toxic shock syndrome toxin (TSST)—in cultural supernatants obtained from different strains of Staphylococcus aureus. The limits of detection of SEA, SEB, and TSST multiplex detection in S. aureus growth medium were 10, 1,000, and 5 pg/mL, respectively. Fifty-nine samples of S. aureus cultural supernatants were tested with the xMAP assay. The developed assay has proved highly effective detection of the natural toxins in the samples obtained due to bacterial cells cultivation. In prospect, the developed test system can be used in clinical diagnostics and in monitoring of foodstuffs and environmental objects.  相似文献   

15.
The pectin substances have been isolated fromEremurus regelii Vved., their qualitative and quantitative monosaccharide compositions have been determined, and their physicochemical properties have been studied. The partial hydrolysis of the pectin gave a galacturonan. On the basis of the results of periodate-nitric acid oxidation, enzymatic hydrolysis, and methylation it has been shown that in the galacturoman the galacturonic acid residues are linked by -(1 4)-glycosidic bonds.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 172–174, March–April, 1985.  相似文献   

16.
An acid form of ricin — ricin T — with a molecular weight of 58 kDa, an isoelectric point, pI, of 7.0–7.1, and a sedimentation coefficient of 4.60 S has been isolated from the seeds of the Central Asian castor-oil plantRicinus communis by gel filtration on Sephadex G-75 followed by ion exchange chromatography on DEAE- and CM-celluloses. The amino acid composition and the N-terminal amino acid residues of ricin T have been determined.  相似文献   

17.
The solvent extraction of Yb(III) by 1-(2-pyridylazo)-2-naphthol (PAN or HL) in carbon tetrachloride from aqueous—ethanol phase has been investigated as a function of thepH X of the polar phase and the concentrations ofPAN or ethanol (EtOH) in the organic phase. It was confirmed that the addition of ethanol to the aqueous phase causes an increase of the Yb(III) distribution coefficient. The equation for the extraction reaction has been suggested as: $$Yb(H_2 O)_{m(^p )}^{3 + } + 3H L_{(o)} + t Et OH_{(o)} \rightleftharpoons Yb L_3 \left( {EtOH} \right)_{t(o)} + 3H_{(^p )}^ + + mH_2 O$$ wheret changes from 0 to 3. The extraction equilibrium constant (K ex ) and two-phase stability constants (β 3 × ) for the YbL 3 (EtOH)3 complex have been evaluated. The formation of solvates YbL 3 (EtOH) t is probably the main reason of the synergistic effect which was observed.  相似文献   

18.
Six new Cd(II) and Zn(II) macrocyclic Schiff base complexes from cyclocondensation of 2,6-diacetylpyridine and three different liner aromatic amines have been investigated. The resulting ligands, L1 and L2 are 17- and L3 18-membered pentaaza macrocycles. The complexes have been characterized by a variety of methods such as IR, elemental analysis, EI-Mass and conductivity measurements and in the case of cadmium complex by 1H and 13C NMR spectroscopy. The crystal structure of [CdL1(CH3OH)](ClO4)2 has been determined. In this complex, the Cd(II) ion is coordinated to five nitrogen donor atoms of the ligand and one oxygen atom from methanol in a N5O environment. The geometry around the cadmium can be better described as in a slightly distorted pentagonal-pyramidal. The synthesized compounds have antibacterial activity against the three gram-positive bacteria: S. aureus, B. cereus and C. xerosis, and also against the three gram-negative bacteria: E. coli, K. pneumoniae and P. vulgaris. The results show that the antibacterial activity of cadmium complexes is greater than that of zinc complexes.  相似文献   

19.
Electromotive-force measurements of the cell $$Pt;H_2 \left( {g,1{\text{ }}atm} \right)|HCl\left( {{\text{m}}_A } \right),NaCl\left( {{\text{m}}_B } \right)|AgCl;Ag$$ have been made at temperatures between 5 and 45°C at values ofm A+m B of 0.1, 0.3809, 0.6729, and 0.8720 mole-kg?1. The activity coefficients of HCl in HCl/NaCl mixtures and the Harned coefficients α12 have been obtained. The change of α12 with total molality is consistent with the existence of binary interactions between H+ and Na+ ions. The linear variation of the relative partial molal heat content with the fraction of NaCl in the mixture suggests that an analog of the Harned rule exists for this thermodynamic quantity.  相似文献   

20.
Water-soluble polysaccharides have been isolated from the bulbs ofAllium longicuspis Rgl. By fractionating the combined water-soluble polysaccharides, homogeneous polysaccharides with molecular weights of 15,500 and 5100 have been isolated. It has been shown by spectral and chemical methods that they consist of glucofructans of a mixed type containing glycosidic bonds of the inulin (2 1) and levan (26) types in a ratio of 2.1:1.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 703–707, November–December, 1984.  相似文献   

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