Effects of light and chloramphenicol stress on incorporation of nitrogen into cyanophycin in Synechocystis sp. strain PCC 6308.
(1)H NMR spectroscopy was used to compare the uptake of nitrogen into cyanobacterial cyanophycin from two sources: from the breakdown of intracellular proteins and amino acids, and directly from the external growth medium. Cells grown initially in medium containing (14)N-nitrate were transferred to (15)N-nitrate medium in the presence of chloramphenicol in both low (4 microE m(-2) s(-1)) and normal (100 microE m(-2) s(-1)) light, and in low light alone. Cyanophycin was separated from cells and analyzed by (1)H NMR spectroscopy. Cyanophycin is synthesized both from (14)N (degradation of cellular proteins) and from (15)N in the medium, the latter at a faster rate and to a greater extent under all conditions. SDS-PAGE showed that cyanophycin synthesis takes place by addition of monomers to already synthesized polymer.
Allen
Mary M
MM
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA. mallen@wellesley.edu
Yuen
Courtney
C
Medeiros
Lea
L
Zizlsperger
Nora
N
Farooq
Maliha
M
Kolodny
Nancy H
NH
D001426:Bacterial Proteins; D002701:Chloramphenicol / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D008027:Light; D009584:Nitrogen / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D010940:Plant Proteins / Q000096:biosynthesis*; D013045:Species Specificity; D046939:Synechocystis / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects
D001426:Bacterial Proteins; D010940:Plant Proteins; C024250:cyanophycin; D002701:Chloramphenicol; D009584:Nitrogen