Loading...
Please wait, while we are loading the content...
Similar Documents
Cyanobacteria in celss: growth strategies for nutritional variation and nitrogen cycling
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Fry, I. V. Packer, L. |
| Copyright Year | 1990 |
| Description | Cyanobacteria (blue-green algae) are versatile organisms which are capable of adjusting their cellular levels of carbohydrate, protein, and lipid in response to changes in the environment. Under stress conditions there is an imbalance between nitrogen metabolism and carbohydrate/lipid synthesis. The lesion in nitrogen assimilation is at the level of transport: the stress condition diverts energy from the active accumulation of nitrate to the extrusion of salt, and probably inhibits a cold-labile ATP'ace in the case of cold shock. Both situations affect the bioenergetic status of the cell such that the nitrogenous precursors for protein synthesis are depleted. Dispite the inhibition of protein synthesis and growth, photosynthetic reductant generation is relatively unaffected. The high O2 reductant would normally lead to photo-oxidative damage of cellular components; however, the organism copes by channeling the 'excess' reductant into carbon storage products. The increase in glycogen (28 to 35 percent dry weight increase) and the elongation of lipid fatty acid side chains (2 to 5 percent dry weight increase) at the expense of protein synthesis (25 to 34 percent dry weight decrease) results in carbohydrate, lipid and protein ratios that are closer to those required in the human diet. In addition, the selection of nitrogen fixing mutants which excrete ammonium ions present an opportunity to tailor these micro-organisms to meet the specific need for a sub-system to reverse potential loss of fixed nitrogen material. |
| File Size | 463838 |
| Page Count | 14 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910022472 |
| Archival Resource Key | ark:/13960/t7gr1td0b |
| Language | English |
| Publisher Date | 1990-03-01 |
| Access Restriction | Open |
| Subject Keyword | Man/system Technology And Life Support Nitrogenation Assimilation Cycles Mutations Carbohydrates Oxygen Lipids Glycogens Nitrogen Carbon Blue Green Algae Fatty Acids Proteins Diets Ammonia Depletion Nitrogen Metabolism Protein Synthesis Closed Ecological Systems Bacteria Lesions Photosynthesis Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
