Fatty acid composition from the marine red algae Pterocladiella capillacea (S. G. Gmelin) Santelices & Hommersand 1997 and Osmundaria obtusiloba (C. Agardh) R. E. Norris 1991 and its antioxidant activity

ABSTRACT This study evaluated the chemical composition and antioxidant activity of fatty acids from the marine red algae Pterocladiella capillacea (S. G. Gmelin) Santelices & Hommersand 1997 and Osmundaria obtusiloba (C. Agardh) R. E. Norris 1991. The gas chromatography mass spectrometry (GC-MS) identified nine fatty acids in the two species. The major fatty acids of P. capillacea and O. obtusiloba were palmitic acid, oleic acid, arachidonic acid and eicosapentaenoic acid. The DPPH radical scavenging capacity of fatty acids was moderate ranging from 25.90% to 29.97%. Fatty acids from P. capillacea (31.18%) had a moderate ferrous ions chelating activity (FIC), while in O. obtusiloba (17.17%), was weak. The ferric reducing antioxidant power (FRAP) of fatty acids from P. capillacea and O. obtusiloba was low. As for β-carotene bleaching (BCB), P. capillacea and O. obtusiloba showed a good activity. This is the first report of the antioxidant activities of fatty acids from the marine red algae P. capillacea and O. obtusiloba.

Regulating promoter element of iron-dependent gene FRP1 in Candida albicans by site-directed mutation / 生物工程学报

Microarray analysis revealed that the expression of ferric reductase (FRP1) can be regulated by the Riml01 protein. In order to find new transcriptional regulatory element in the promoter of FRP1, we analyzed the 1000 bp sequence upstream of ATG to find 2 potential Riml01p binding sites. We generated site-specific mutations in each of the two sites and fused these mutated promoters to LacZ. Then the promoter-LacZ fusion construct was recombinant into wild type and riml01-/- strains for beta-galactosidase assay. The results revealed that the FRP1 was up-regulated in alkaline pH and this was caused by iron starvation. The -650 site, not the -160 site, had an important role in FRP1 Riml01p-dependent expression. We conclude that Riml01p may interact with the -650 binding site of the promoter to regulate the FRP1 expression.

Ferric reductase, superoxide dismutase and alkaline phosphatase activities in siderophore producing fungi.

Enzymes associated with release of iron from internalized ferrated siderophore (ferrisiderophore reductase), with damage to the cell at high iron concentration (superoxide dismutase) and siderophore synthesis (alkaline phosphatase), were examined in 3 test fungi viz., Aspergillus sp. ABp4, Aureobasidium pullulans and Rhizopus sp. Extracellular ferrisiderophore reductase activity was present in all the three fungi, but Aureobasidium pullulans, that showed the highest activity (84.3 microM min(-1)), was the only one to produce intra-cellular ferric reductase (147.9 microM min(-1)). Superoxide dismutase was produced by Aureobasidium pullulans and Rhizopus sp., but not by Aspergillus sp. ABp4, that showed intra-cellular enzyme activity in case of ferric reductase and alkaline phosphatase. Maximum SOD activity was seen in Aureobasidium pullulans both extra-cellularly (93.83 ng ml(-1)) and intra-cellularly (57.14 ng ml(-1)). All the test fungi examined, produced intra-cellular alkaline phosphatase. There was no extracellular alkaline phosphatase. Among the three fungi, Aureobasidium pullulans showed highest alkaline phosphatase activity (129.9 microM min(-1)) and Aspergillus sp. ABp4 the least (76.4 microM min(-1)).