Nitrogen control of chloroplast development: Progress report

Technical Report · Sun Nov 01 04:00:00 EST 1987

OSTI ID:5859990

Schmidt, G W

A manifestation of nitrogen deficiency in vascular plants and algae is chlorosis, indicating that chloroplast biogenesis can be strongly restricted by direct or indirect effects of nitrogen assimilation products. To define the molecular basis of nitrogen responses we are using Chlamydomonas reinhardtii. Depending on the levels of ammonium, steady-state deficiency conditions are established such that the cellular levels of chlorophylls and xanthophylls are depressed. Chloroplasts in nitrogen-deficient cells contain appreciable levels of carbon assimilation enzyme and thylakoids with high electron transport activities. However, the light harvesting complexes are nearly absent and Photosystem I exhibits unusual characteristics. Studies of rates of protein synthesis by in vivo pulse-chase labeling and levels of RNAs encoded by the chloroplast and nuclear genomes have been initiated: the accumulation of transcripts for the nuclear light-harvesting apoproteins is dramatically altered qualitatively and quantitatively; there is no major effect on chloroplast RNAs but, in general, these are inefficiently utilized for protein synthesis until nitrogen is provided to the cultures. Supplying nitrogen results in an almost immediate release of chloroplast mRNAs from a translational arrest but the stimulation of the accumulation of nuclear transcripts for light-harvesting apoproteins does not occur until after a 1-2 hour lag.

• Research Organization: Georgia Univ., Athens (USA). Dept. of Botany
• DOE Contract Number: FG09-84ER13188
• OSTI ID: 5859990
• Report Number(s): DOE/ER/13188-4; ON: DE88003186
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
14 SOLAR ENERGY
140504 -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
550201 -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALGAE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL STRESS
CAROTENOIDS
CHLAMYDOMONAS
CHLOROPHYLL-BINDING PROTEINS
CHLOROSIS
CLONING
CONTINUOUS CULTURE
DAYS LIVING RADIOISOTOPES
DNA-CLONING
DOCUMENT TYPES
ELEMENTS
HYDROCARBONS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MEMBRANES
MESSENGER-RNA
MICROORGANISMS
NITROGEN
NONMETALS
NUCLEI
NUCLEIC ACIDS
NUTRITIONAL DEFICIENCY
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOTOSYNTHETIC MEMBRANES
PHOTOSYNTHETIC REACTION CENTERS
PHYSIOLOGY
PIGMENTS
PLANTS
PROGRESS REPORT
PROTEINS
RADIOISOTOPES
RNA
TERPENES
TRACER TECHNIQUES
UNICELLULAR ALGAE