Levels of trehalose and glycogen inArthrobacter globiformis under conditions of nutrient starvation and osmotic stress

Abstract

Cells ofArthrobacter globiformis grown in carbohydrate-rich media were found to contain large quantities of low-M_r carbohydrates (800 μg/mg protein) and only small amounts of amino acids, in addition to high amounts of glycogen (2 mg/mg protein). At increasing osmotic values of the medium, low-M_r carbohydrate levels increased to 1300 μg/mg protein. Low-M_r pools were extracted from the cells with hot 75% ethanol, and subjected to thin layer, gel and gas-liquid chromatography. They turned out to consist mainly of α,α-trehalose. Levels of trehalose inArthrobacter cells have the tendency to remain constant, both during nutrient exhaustion (resulting in glycogen consumption), and on addition of excess of carbon source to the medium (resulting in an increased glycogen content of the cells). The stress-tolerant properties ofArthrobacter (resistance to nutrient starvation, desiccation and high salt concentration) are discussed with respect to the high glycogen and trehalose contents of the cells.