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http://hdl.handle.net/2142/19434 Rinehart, Kenneth L., Jr. Choi, Byoung Wook 2011-05-07T12:07:26Z 2011-05-07T12:07:26Z 10000-01-01 1992 Biosynthetic studies compounds showed that the Adda unit of nodularin was derived from C-2, C-3 and the phenyl ring of scL-phenylalanine as well as acetate and methionine. A separate feeding experiment with (2-$\sp{13}$C) pyruvate suggested that the methylaspartate (MeAsp) unit could be derived from pyruvate and acetate. An acyclic nodularin, N-842, was isolated from the cultured Nodularia spumigena and its structure was assigned as Adda- scD-Glu-Mdhb- scD-MeAsp- scL-Arg-OH. Isolation of nodularin and N-842 from a continuously cultured batch suggested that N-842 is a biogenetic precursor to nodularin. Based on these findings, biogenetic pathways of nodularin and the structurally related compound, microcystin-LR, are proposed. Dihydro derivatives of nodularin and microcystin-LR were prepared by sodium borohydride reduction of the dehydroamino acid residues. The stereochemistry of each reduced amino acid was obtained by acid hydrolysis of dihydro derivatives followed by GC analysis of their trifluoroacetyl methyl ester derivatives. Deuterated derivatives were prepared in an analogous manner using sodium borodeuteride. Analysis of FABMS/MS spectra of the linear peptides, which were obtained from ozonolysis followed by sodium borohydride reduction and acid treatment of microcystins, allowed elucidation of the sequence of the microcystins. The fate of the dihydromicrocystin-LR's in pigs was studied by isolating the radioactive metabolites from tritiated dihydromicrocystin-LR injected pigs. Greater than 90% of the radioactive material from the liver proved to be the parent toxins. The remaining radioactivity was attributed to several unidentified metabolites. Unlabeled 4,5,6-tri-O-benzylvalienamine was synthesized from methyl $\alpha$- scD-glucopyranoside in 12 steps in an overall yield of 5%. Similarly, (7-$\sp{14}$C) -4,5,6-tri-O-benzylvalienamine was prepared from the reaction of 2 scL-(2,4/3)-2,3,4-tribenzyloxy-cyclohex-5-enone with (methyl-$\sp{14}$C) methyltriphenylphosphonium bromide in 5 steps for an overall radiochemical yield of 9%. The $\sp1$H and $\sp{13}$C NMR spectra of fortimicin B were assigned by use of homonuclear correlation spectroscopy, heteronuclear correlation spectroscopy and the Attached Proton Test. Feeding experiments with $\sp{14}$C-labeled plausible precursors showed that scD-glucose was not incorporated into fortimicins and scD-maltose was incorporated. Made available in DSpace on 2011-05-07T12:07:26Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9236426.pdf: 8841251 bytes, checksum: 803af04845796972705dc227b165148d (MD5) Previous issue date: 1992 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:36:56Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:15:05-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9236426 (UMI)AAI9236426 eng Copyright 1992 Choi, Byoung Wook Health Sciences, Toxicology Chemistry, Biochemistry Chemistry, Organic Studies on secondary metabolites produced by actinomycetes and cyanobacteria text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.