Morphological and physiological differences in Synechococcus elongatus during continuous cultivation at high iron, low iron, and iron deficient medium

Title:

Morphological and physiological differences in Synechococcus elongatus during continuous cultivation at high iron, low iron, and iron deficient medium

Creator:

Benešová, J., Ničková, K., Ferimazová, N., and Štys, D.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:5c146bf6-e51e-44f0-b115-4f00daafbf5d
uuid:5c146bf6-e51e-44f0-b115-4f00daafbf5d
issn:0300-3604
doi:10.1023/A:1007274000087

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

Thermophilic unicellular cyanobacterium Synechococcus elongatus Näg. var. thermalis Geitl. strain Kovrov 1972/8 was cultivated in continuous flow reactor to simulate conditions occurring in nature in regions with low iron concentration. Two degrees of iron deprivation were established: (a) low iron (LI) conditions (9.0 µM Fe) when cells still maintained maximal growth rate but already exhibited changes in photosynthetic apparatus, and (b) iron deficient (ID) conditions (0.9 µM Fe) when cell growth rate decreased and extensive morphological and functional changes were observed. A decrease in the cellular content of phycobilin antenna was observed in both ID and LI cells and an increase of carotenoid concentration only in the ID culture. Morphologically, ID cells showed a decrease in the amount of phycobilins and in the number of thylakoid membranes. This suggests that S. elongatus responds to decrease in iron availability by substitution of the phycobilisomes by antennae containing chlorophyll (Chl) and carotenoids. Photochemical activity of photosystem (PS) 2, determined as Fv/Fm ratio was similar in high iron (HI) and LI cultures and approximately five times lower in ID culture. On the other hand, the activity of the whole electron transport chain showed the opposite tendency: the relative rates of the CO2-dependent oxygen evolution in HI : LI : ID cultures were approximately 1 : 2 : 4. Thus in nutrient stress the photosynthetic apparatus preserved its activity despite the decrease in the amount of both Chl-binding complexes and thylakoid membranes. and J. Benešová ... [et al.].

Language:

Multiple languages

Rights:

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

Coverage:

233-241

Source:

Photosynthetica | 2000 Volume:38 | Number:2

Harvested from:

CDK

Metadata only:

false