Isolation and Characterization of High CO2-Requiring-Mutants of the Cyanobacterium Synechococcus PCC7942

作者：G. Dean Price, Murray R. Badger · 发表于：PLANT PHYSIOLOGY · 年份：1989 · DOI：10.1104/pp.91.2.514 · 被引用次数：182 · 研究领域：Photosynthetic Processes and Mechanisms、Algal biology and biofuel production、Hemoglobin structure and function

A total of 24 high CO(2)-requiring-mutants of the cyanobacterium Synechococcus PCC7942 have been isolated and partially characterized. These chemically induced mutants are able to grow at 1% CO(2), on agar media, but are incapable of growth at air levels of CO(2). All the mutants were able to accumulate inorganic carbon (C(i)) to levels similar to or higher than wild type cells, but were apparently unable to generate intracellular CO(2). On the basis of the rate of C(i) release following a light (5 minutes) --> dark transition two extreme phenotypes (fast and slow release mutants) and a number of ;intermediate' mutants (normal release) were identified. Compared to wild-type cells, Type I mutants had the following characteristics: fast C(i) release, normal internal C(i) pool, normal carbonic anhydrase (CA) activity in crude extracts, reduced internal exchange of (18)O from (18)O-labeled CO(2), 1% CO(2) requirement for growth in liquid media, normal affinity of carboxylase for CO(2), and long, rod-like carboxysomes. Type II mutants had the following characteristics: slow C(i) release, increased internal C(i) pool, normal CA activity in crude extracts, normal internal (18)O exchange, a 3% CO(2) requirement for growth in liquid media, high carboxylase activity, normal affinity of carboxylase for CO(2), and normal carboxysome structure but increased in numbers per cell. Both mutant phenotypes appear to have genetic lesions that result in an inability to convert intracellular HCO(3...