Paths of deactivation of excited bacteriochlorophyll с in the green photosynthetic bacterium Prosthecochloris aestuarii

Title:

Paths of deactivation of excited bacteriochlorophyll с in the green photosynthetic bacterium Prosthecochloris aestuarii

Creator:

Dudkowiak, A., Cegielski, R., Ptak, A., Planner, A., Chrzumnicka, E., Hanyž, I., and Frackowiak, D.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:4867d972-779d-4540-a05c-85690176dd52
uuid:4867d972-779d-4540-a05c-85690176dd52
urnnbn:urn:nbn:cz:aba007-000fk6

Type:

model:internalpart and TEXT

Format:

print

Description:

Absorption , fluorescence, delayed emission and photoacoustic spectra were obtained for the green photosynthetic bacterium. Whole cells incorporated in fluid (culture medium, viscous solution of polyvinyl alcohol, glycol) and rigid (isotropic and stretched polyvinyl alcohol film) media were investigated. The polarized absorption spectra of the stretched polyvinyl alcohol sample showed that the Qy transition moments of chlorosomal bacteriochlorophyll с was almost parallel to the film axis. Bacteriochlorophyll (BChl) с degradation occurred in some of the samples during prolonged storage and as a result a pigment absorbing at 670 nm, which was disaggregated BChl с or/and bacteriopheophytin c, was formed. This pigment was unoriented in stretched polyvinyl alcohol. The fluorescence spectrum of native cells can be analyzed using three Gaussian components at 754, 781 and 813 pm. The first component seems to be related to BChl с aggregates and the others to BChl a complexes. The time-resolved delayed luminescence spectra showed that practically all the complexes of green bacteria exhibited delayed emission but the decay times and intensities were different for the different complexes. In the photoacoustic spectra two maxima of the chlorosomal BChl с forms were well resolved and located at 748 and 765 nm. The photoacoustic maximum at 830 nm was probably related to the reaction centre (RC). In the Soret band the largest peak of the photoacoustic spectra was observed at 473 nm which showed that carotenoids absorbing in this range were losing more excitation by heat. The BChl с aggregates attached to chlorosome rods exhibited a peak at 446 nm. The efficient thermal deactivation also showed a BChl a located in RC (peak at 846 nm) and long-wavelength BChl a antenna complexes with a deactivation peak at 884 nm.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

183-191 and 25-33

Source:

Photosynthetica | 1994 Volume:30 | Number:2

Harvested from:

CDK

Metadata only:

false