A Preliminary Study Of The Siderophore From Rhodopseudomonas Palustris CQV97

Siderophores play an important role in transfer insoluble iron and maintain theprcess of iron nutrition in the microbe，and its role in environment and deseasestreatment has become a hot issue. This research has summarized the of thesiderophore，most microbial can produced siderophore in iron-limited condition, butresearch about siderophore from APB is very limited.Based on this, this researchscreened a APB strain named Rhodopseudanonas palustris CQV97which couldproduce siderophores. Then explore the iron ion on growth, photosynthetic pigmentsand the regulation of siderophore synthesis. Use the column chromatography toisolation siderophore from the supernatant of limited iron culture solution. And effectof pigments synthesis by siderophore. The results are as follows:Rhodopseudomonas palustris CQV97was capable of producinghydroxamate-type of siderophore. Siderophore production reached the highest yieldwithout the addition of ferric chloride into medium. With increasing ferric chlorideconcentration, lag phase of cell growth was shorten, the cell growth rate, finalbiomass and the total amounts of carotenoid and bacteriochlorophyll a significantlyincreased, the characteristic absorption maxima of carotenoids from pigment extractsblueshifted. The addition of80μmol/L and100μmol/L ferric chloride into mediumcaused a increase in the amount of bacteriochlorophyll and carotenoid pigments aswell as biomass, whereas siderophore production decreased. Iron concentration hadlittle effect on the compositions and relative contents of bacteriochlorophylls a,whereas significantly affected that of carotenoid, rhodopin predominated instead ofspirillxanthin, culture tend to accumulate the Cars having shorter conjugated doublebonds at the expense of longer conjugated double bonds with increasing ferricchloride concentration. The changes in the carotenoid composition were consistentwith that of the blue shift of absorption spectra of pigment extracts.AB-8macroporous resin column chromatography can effective remove most ofpigment and protein. Siderophore has an important role in regulate growth andpigment synthesis. And it could shrink the lag phase of growth, increase the growth rate, biomass and pigments. High dose of siderophore will limited the promotion ofgrowth. When the iron ion concentration more than80μmol/L siderophore does notmuch affect the growth. When siderophore concentrations rise that BChl aPcontentsincrease and BChl aGG、BChl aDHGG、BChl aTHGGdecline. And Car accumulated indifferent concentrations of iron that has concentration has significant differences inthe response by siderophore. Otherwise, E.coli can utilized siderophore that producedby CQV97. It can promoted E.coli growth in limited iron medium.Rhodopseudomonas palustris CQV97can produce the hydroxamic acid typesiderophores. Iron and siderophores has an important role in regulating cell growthand pigment biosynthesis.