Occurrence, Isolation, and Characterization

The eight species of Chinese locoweeds referred to above have been shown to produce swainsonine (378) as a result of Undifilum infection. Methods for the detection of swainsonine in Undifilum in such oriental locoweeds include HPLC with an evaporative light-scattering detector  

Some methods for the isolation, detection, and characterization of swainso-nine (378) require mention. A novel analytical procedure based on small-scale hquid—hquid extraction of dried plant material, isolation by extraction with a cation-exchange resin, and quantitation by reversed-phase HPLC coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (LC-MS/MS) was devised to ewiluate the distribution of swainsonine in populations of several North American locoweeds of the genus Oxytropis the limit of detection was about 0.001% in dry plant material, which is at the 

The molecular geometry of swainsonine (378) has been modeled with the aid of the density functional tight-binding (DFTB) technique as a prelude to computing its intercalation into DNA. The calculations, the first of their kind, showed the alkaloid to be a good electron acceptor toward 

Two important reviews relate to the synthesis of swainsonine (378) and analogs. In 2000 El Nemr surveyed the many reported syntheses not only of the alkaloid and its stereoisomers, but also of some of its positional isomers and various deoxy and hydroxy analogs. This review includes detailed step-by-step reaction schemes for the unnatural analogs, a luxury that cannot be emulated in the present survey owing to limitations of space. In 2005 Pyne updated El Nemr s review to include syntheses published between 1999 and 2004.  

Numerous syntheses of swainsonine s synthetic diastereoisomers have been pubHshed. Detailed discussion of these (unless they occur in routes that produce swainsonine as well) would swell this review to unmanageable lengths but for completeness, the following references are provided (—)-2-ept -swainsonine (379), its 8-O-benzyl ether, and its enantiomer, which appears in the literature as (4-)-l,8,8a-tri-q) -swainsonine (cni-379) (—)-8-ept-swainsonine (380) swainsonine (381)  

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III. Some Aspects of the Occurrence, Isolation, and Characterization of Lysozyme and a-LACTALBUMiN... 

The culture filtrates of T. reesei contained a large number of both cellulolytic and hemicellulolytic enzymes, which could be partially separated by chromatofocussing (Fig. 1). Of the cellulolytic enzymes, several endoglu-canases and two cellobiohydrolases have already been isolated and characterized (30). Some of the endoglucanases isolated are nonspecific and have xylanase activity (31). The two major xylanase (Xyl) peaks in Figure 1 corresponded to pi-values of above 7.5 and 5.5. When the former enzyme was further purified (24), its isoelectric point was found to be about pi 9 (Table I). Previously, the presence of at least three electrophoretically different xylanases in T. reesei culture filtrates was reported, with the most acidic one shown to have broad substrate specificity (10). This is in agreement with the reported occurrence of three xylanases (pi > 7, pi 5.1, pi... 

The distribution of the principal indigenous enzymes in milk and their catalytic activity are listed in Table 8.1. In this chapter, the occurrence, distribution, isolation and characterization of the principal indigenous enzymes will be discussed, with an emphasis on their commercial significance in milk. 

By comparison with the mercury(I) and mercury(II) ions (Chapter 56.1), the coordination chemistry of (10) and (11) has received little attention. Both ions disproportionate to Hg° and Hg2+ /Hg2+ in media more basic than those from which they can be prepared. However, the existence of (11) (which can be regarded as a complex of (10) with Hg°) and the cation-anion coordination found in solid salts of (10)38 suggest that this ion, at least, might form stable complexes with suitable weak donors. In addition, the formation of as yet incompletely characterized Hg2BrCI04 2SnBr2, which may contain both Hg—Hg and Hg—Sn bonds,42 and the isolation and characterization of [ (np3)Co HgHg Co(np3) ] (1 see Section 11.2) may presage a wider occurrence of catenated heterometallic polymercury species. Slow disproportionation of (11) into (10) and Hg3-X(MF6) occurs even in liquid S02.39 As discussed below, there is evidence for mercury atom transfer between (10) and (11) in liquid S02. 

Loewus, M.W., and Loewus, F.A., 1971, The isolation and characterization of D-glucose 6-phosphate cycloaldolase (NAD-dependent) from Acer pseudoplatanus L. cell cultures. Is occurrence in plants. Plant Physiol. 48 255-260. 

The occurrence in Solanaceae is documented for 12 genera, Atropa, Brunfelsia, Datura, Duboisia, Flyoscyamus, Lycium, Mandragora, Nicandra, Physalis, Scopolia, Solanum, and Withania [2,89]. Our group isolated and characterized calystegines A3, A5 (72), Bi, B2, and... 

Scoulerine (145 R = H), the main constituent of Argemone albiflora, had not been previously obtained from Argemone species.The previously named alkaloid HF 1 isolated from Hunnemannia fumariaefolia was found to be identical with ( —)-scoulerine. The co-occurrence of (— )-tetrahydropalmatine (145 R = Me) and (-f )-armepavine in Argemone turnerae has been established for the first time.The isolation and characterization of two artefact alkaloids, berberine chloroform (146 R + R = CH2 R = H,CCl3) and palmatine chloroform (146 R = R = Me, R = H,CCl3), from Berberis lycium have... 

Takahashi K, Hiwada K, Kokubu T (1986) Isolation and characterization of a 34,000-dalton calmodulin- and F-actin-binding protein from chicken gizzard smooth muscle. Biochem Biophys Res Commun 141 20-26 Takahashi K, Hiwada K, Kokubu T (1987) Occurrence of anti-gizzard P34K antibody cross-reactive components in bovine smooth muscles and non-smooth muscle tissues. Life Sci 41 291-296... 

Rohrlack, T., Henning, M., and Kohl, J.-G., Isolation and characterization of colony-forming Microcystis aeruginosa strains, in Cyanotoxins—Occurrence, Causes, Consequences, Chorus, L, Ed., Springer, Berlin, 2001, 152. 

The atisines generally occur in small amounts (0.05-1 %) in plant material, freqently accompanying one of the aconitines the atisines remain in the mother liquors after the preliminary extraction of the aconitines, and many of these minor alkaloids no doubt still remain to be isolated and characterized. Their common occurrence strongly suggests a chemical relationship between the aconitines and the atisines. 

After the potential occurrence of chiral fullerenes and nanotubes could be inferred from the structural principles of fullerenes [35-37], these carbon spheroids became of practical interest for the first time with the isolation and characterization of D2-symmetrical Cyg by Diederich and coworkers [1]. Obeying the IPR (isolated pentagon rule) and having a closed electronic shell with a fully occupied HOMO (highest occupied molecular orbital), its structure had been theoretically predicted shortly before to be the only stable form of [76]fuUerene... 

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