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851.
852.
Various sugars were introduced by electroporation into perennial ryegrass protoplasts, and the involvement of intracellular
functional groups of the sugars in salt tolerance was investigated. The protoplasts were prepared from the young leaves of
perennial ryegrass, and those into which sugars were introduced were treated with NaCl solution (250 mM, pH 7.0) for 6 h at
10°C. The survival rate of the protoplasts increased when xylitol, cellobiose, 1-kestose, maltose, maltotriose, raffinose
and trehalose were introduced, while no changes occurred when fructose, fucose, galactose, glucose, inositol, mannitol, mannose,
rhamnose, sorbitol, sorbose, fructobiose, lactose and sucrose were introduced. Cellobiose, 1-kestose, maltose, maltotriose,
raffinose and trehalose possess a number of equatorial OH (e-OH) groups that promote the structuration of H2O. Xylitol, however, structures H2O even though it does not possess the e-OH groups. Hence, it is suggested that under conditions of NaCl stress, structured
H2O protects the structure of cell membranes and the activity of enzymes, and that e-OH groups are involved in enhancing salt
tolerance. 相似文献
853.
Gene disruption by plasmid integration in Listeria monocytogenes: insertional inactivation of the listeriolysin determinant lisA 总被引:4,自引:0,他引:4
Michael D. Wuenscher Stephan Köhler Werner Goebel Trinad Chakraborty 《Molecular & general genetics : MGG》1991,228(1-2):177-182
Summary A plasmid integration technique was developed for insertional inactivation of chromosomal Listeria monocytogenes genes. A Listeria-Escherichia coli shuttle vector (pLSV1) was constructed which carried the temperature-sensitive gram-positive replication origin from plasmid pTV32(Ts). An internal fragment of the listeriolysin gene (IisA) was cloned into pLSV1 to create pLSV2. In L. monocytogenes pLSV2 transformants, plasmid pLSV2 integrated into the L. monocytogenes chromosome at a frequency of 2 × 10–3 via lisA homology and these cells could be selected at 42° C using a plasmid-encoded erythromycin resistance. Plasmid integration resulted in disruption of the lisA gene, production of a truncated, immunologically cross-reactive listeriolysin protein and loss of the hemolytic phenotype. An improved Listeria protoplast transformation method is also described which facilitates genetic manipulation of Listeria species. 相似文献
854.
Sona Pandey Xi-Qing Wang Sylvie A. Coursol Sarah M. Assmann 《The New phytologist》2002,153(3):517-526
855.
Using electrofusion of protoplasts from different dihaploid potato breeding clones, 308 somatic hybrids, i.e. 16.7% of the totally regenerated plants, were obtained. The results indicate that factors such as ‘combining ability’ strongly influence hybrid formation in these intraspecific fusion experiments. Hybrid identification was predominantly carried out by isoenzyme analysis of the peroxidases and/or esterases in polyacrylamide-gradient gel electrophoresis. Further confirmation of the hybrid character was obtained by scoring phenotypic markers (petal colour, stem anthocyanin production, tuber characteristics, etc.) and, in some combinations, by evaluating tolerance against the herbicide metribuzin and nematode resistance against Globodera rostochiensis (Ro 1). The successful inheritance of metribuzin tolerance and nematode resistance confirm that monogenic dominant inherited traits are combined in the hybrids. 相似文献