A combined stress response analysis of Spirulina platensis in terms of global differentially expressed proteins, and mRNA levels and stability of fatty acid biosynthesis genes.
Changes in gene expression play a critical role in enhancing the ability of cyanobacteria to survive under cold conditions. In the present study, Spirulina platensis cultures were grown at the optimal growth temperature, in the light, before being transferred to dark conditions at 22 degrees C. Two dimensional-differential gel electrophoresis was then performed to separate differentially expressed proteins that were subsequently identified by MS. Among all differentiated proteins identified, a protein involved in fatty acid biosynthesis, (3R)-hydroxymyristoyl-[acyl-carrier-protein]-dehydratase encoded by fabZ, was the most up-regulated protein. However, the fatty-acid desaturation proteins were not significantly differentiated. This raised the question of how the unsaturated fatty acid, especially gamma-linolenic acid, content in the cells in the cold-dark shift remained stable compared with that of the cold shift. Thus, a study at the transcriptional level of these desaturase genes, desC, desA and desD, and also of the fabZ gene was conducted. The results indicated that in the dark, where energy is limited, mRNA stability was enhanced by exposure to low temperatures. The data demonstrate that when the cells encounter cold stress with energy limitation, they can maintain their homeoviscous adaptation ability via mRNA stability.
Jeamton
Wattana
W
Pilot Plant Development and Training Institute, King Mongkut's University of Technology, Thonburi, Bangkok, Thailand.
Mungpakdee
Sutada
S
Sirijuntarut
Matura
M
Prommeenate
Peerada
P
Cheevadhanarak
Supapon
S
Tanticharoen
Morakot
M
Hongsthong
Apiradee
A
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003080:Cold Temperature; D015180:Electrophoresis, Gel, Two-Dimensional; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism; D008027:Light; D040901:Proteomics; D020871:RNA Stability; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053545:Spirulina / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D005227:Fatty Acids; D012329:RNA, Bacterial; D012333:RNA, Messenger; D044943:Fatty Acid Desaturases; D006836:Hydro-Lyases