Botany

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End date: 1999Has files: No

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    Effects of Fusarium moniliforme culture extracts and fumonisin B1 on DNA, RNA and protein synthesis by baby hamster kidney cells
    (Springer Netherlands., 1998) Abeywickrama, K.; Bean, G.A.; Kennedy, K..A.
    Baby hamster kidney cells (BHK-21) were exposed to culture filtrates of 4 Fusarium moniliforme isolates containing varying levels of fumonisin B1 (FMB1) and the effects upon RNA, DNA and protein synthesis were monitored. Cells were also grown on medium amended with FMB1 only for comparison. After 24 h incubation FMB1 (100 μg/100 ml medium) reduced protein synthesis by 4% and by 18% after 48 h. Culture filtrates containing the highest levels of FMB1 also caused the greatest inhibition in protein synthesis after 24 h but after 48 h protein synthesis levels were the same as controls even though the FMB1 level was 360 μg/100 ml. Only FMB1 reduced DNA synthesis, by 8% after 24 h but after 48 h DNA levels had increased by 40 % over controls. The culture filtrates containing the highest levels of FMB1 (360 μg/100 ml) reduced DNA synthesis more than 50% after 24 h and 48 h. Culture filtrates containing lesser amounts of FMB1 in some instances stimulated DNA synthesis and inhibited it in others. There was also no correlation in the level of FMB1 with the inhibition of RNA synthesis by BHK cells. It appears that metabolites other than fumonisin produced by F. moniliforme in culture can affect and both stimulate and inhibit RNA, DNA and protein synthesis by BHK cells.
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    A comparative chemosystematical study of the genus Shorea in Sri Lanka
    (Proceedings of the sixth Round Table Conference on Dipterocarps, Bangalore, India, 1999) Perera N I S; Senanayake S P
    The genus Shorea of the Dipterocarpaceae family is represented by 15 species in Sri Lanka, of which 13 are endemic. Because of the existence of different classification systems for this genus, proposed by several authors (Trimen 1974, Ashton 1980, Kostermann 1992), the aim of this study was to determine the taxonomic position of the genus Shorea using flavonoid composition. Flavonoid composition of the leaves of 11 species was studied using chromatographic techniques and UV visible spectroscopy. It was revealed that 48% flavonols, 36% flavones, 63% proanthocyanidins and 13% deoxy compounds were present in the leaves. In this study, a comparison of the flavonoid glycoside distribution patterns of Shorea stipularis and S. hulanidda suggested that the two species should be treated as different entities. However, several authors treat the taxonomic positions of these two species differently.
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    The flavonoids of the genus Lathyrus and a comparison of flavonoid patterns within the tribe vicieae
    (Biochemical Systematics and Ecology, 1993) Ranabahu, P.; Harborne, J.B.
    A leaf survey of Lathyrus showed that the flavonols kaempferol and quercetin were present in 36 of 38 species representing nine sections of the genus. Six glycosides of each flavonol were characterised. Kaempferol 3-sophoroside-7-glucoside, previously reported in L. vernus, was found in four further species. Other distinctive glycosidic patterns in the genus include the 3-robinobioside, the 3-sophoroside and the 3-lathyroside-7-rhamnoside. The two species surveyed in section Pratensis were different from all the others, in having flavones as well as flavonols and, additionally, in having proanthocyanidins. These differences in leaf flavonoid patterns also extended to the flowers, pods and seeds. Isoflavone accumulation was confirmed in L. montanus but otherwise the genus was depauperate in isoflavones. A comparison of patterns found in Lathyrus with those of Cicer, Lens, Pisum and Vicia indicate that each genus has a distinctive flavonoid profile.
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    Leaf flavonoid glycosides as chemosystematic characters in Ocimum
    (Biochemical Systematics and Ecology, 1993) Grayer, R.J.; Kitea, G.C.; Veitcha, N.C.; Eckerta, M.R.; Marin, P.D.; Senanayake, S.P.; Paton, A.J.
    Abstract Thirty-one accessions of nine species belonging to three subgenera of Ocimum (basil, family Lamiaceae) were surveyed for flavonoid glycosides. Substantial infraspecific differences in flavonoid profiles of the leaves were found only in O. americanum, where var. pilosum accumulated the flavone C-glycoside, vicenin-2, which only occurred in trace amounts in var. americanum and was not detected in cv. Sacred. The major flavonoids in var. americanum and cv. Sacred, and also in all other species investigated for subgenusOcimum, were flavonol 3-O-glucosides and 3-O-rutinosides. Many species in subgenus Ocimum also produced the more unusual compound, quercetin 3-O-(6?-O-malonyl)glucoside, and small amounts of flavone O-glycosides. The level of flavonol glycosides produced was reduced significantly in glasshouse-grown plants, but levels of flavone glycosides were unaffected. A single species investigated from subgenusNautochilus, O. lamiifolium, had a different flavonoid glycoside profile, although the major compound was also a flavonol O-glycoside. This was identified as quercetin 3-O-xylosyl(1??2?)galactoside, using NMR spectroscopy. The species investigated from subgenus Gymnocimum, O. tenuiflorum (=O. sanctum), was characterised by the accumulation of flavone O-glycosides. These were isolated, and identified as the 7-O-glucuronides of luteolin and apigenin. Luteolin 5-O-glucoside was found in all nine species of Ocimumstudied, and is considered to be a key character for the genus.