Properties of Chlorella cells grown under various photo-heterotrophic conditions

1. Chlorella ellipsoidea was cultured under photo-heterotrophicconditions. Cells showed most favorable growth when 0.2% glucosewas added at the start to the inorganic nutrient medium. 2. Treatment with a mixed solvent, methanol/hexane: 4/3, gavehighly decolorized cells. Molasses alone and pyruvate in combinationwith glucose or with molasses and glucose were effective inobtaining a high yield of chlorophyll and carotenoid pigments. 3. The nitrogen content was lower in bleached cells than innormal cells. Protein yield obtained by the urea soaking methodwas higher with bleached cells than with normal cells. 4. Electron microscopic studies revealed that the outer partof normal cells consists of two layers, an electron-dense innerlayer and an electron-lucent outer layer, whereas, that of bleachedcells consists of only an electron-dense layer. (Received August 28, 1969; )     

A step towards understanding plant responses to multiple environmental stresses: a genome‐wide study

In natural habitats, especially in arid areas, plants are often simultaneously exposed to multiple abiotic stresses, such as salt, osmotic and heat stresses. However, most analyses of gene expression in stress responses examine individual stresses. In this report, we compare gene expression in individual and combined stresses. We show that combined stress treatments with salt, mannitol and heat induce a unique pattern of gene expression that is not a simple merge of the individual stress responses. Under multiple stress conditions, expression of most heat and salt stress‐responsive genes increased to levels similar to or higher than those measured in single stress conditions, but osmotic stress‐responsive genes increased to lower levels. Genes up‐regulated to higher levels under multiple stress condition than single stress conditions include genes for heat shock proteins, heat shock regulators and late embryogenesis abundant proteins (LEAs), which protect other proteins from damage caused by stresses, suggesting their importance in multiple stress condition. Based on this analysis, we identify candidate genes for engineering crop plants tolerant to multiple stresses.