Synthesis of glycerophosphorylated cyclic (1,2)-{beta}-glucans in Rhizobium meliloti strain 1021 after osmotic shock

• Published in: Microbiology (Society for General Microbiology) 1995-03, Vol.141 (3), p.583-588
• Main Authors: Breedveld, Michael W, Miller, Karen J
• Format: Article
• Language: English
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-141-3-583

1 Department of Food Science, The Pennsylvania State University, University Park, PA 16802, USA 2 Graduate Programs in Plant Physiology, The Pennsylvania State University, University Park, PA 16802, USA 3 Genetics, The Pennsylvania State University, University Park, PA 16802, USA ABSTRACT Summary: The transfer of phosphoglycerol moieties from phosphatidylglycerol to the cyclic (1,2)-β-glucans in growing cultures of Rhizobium meliloti strain 1021 was investigated using pulse-chase experiments with [ 3 H]glycerol and/or [ 14 C]glucose. No transfer occurred when cells were grown and pulse-chased in a medium containing 0.4 M NaCl. However, radiolabelled glycerophosphorylated cyclic (1,2)-β-glucans could be detected within 30 min after transfer of these cultures to a low-osmolarity medium. Conversely, when low-osmolarity cultures were shifted to a high-osmolarity medium containing 0.4 M NaCl or 0.8 M sucrose, the transfer of phosphoglycerol substituents to the cyclic (1,2)-β-glucans was inhibited. Further experiments revealed that the transfer of phosphoglycerol substituents to the cyclic (1,2)-β-glucans occurs within the periplasmic compartment. 5 Karen J. Miller (Department of Food Science). Tel: [phone]. Fax: [phone]. Keywords: hyperosmotic shock, hypoosmotic shock, glycerophosphate, cyclic (1,2)-β-glucans, Rhizobium meliloti