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411.
M. Sharma S. K. Rai D. K. Purshottam M. Jain D. Chakrabarty A. Awasthi K. N. Nair Ashok Kumar Sharma 《Acta Physiologiae Plantarum》2009,31(2):379-383
An in vitro process for rapid clonal propagation of Clerodendrum serratum (Linn.) Moon, a rare and threatened medicinal shrub, has been developed. Nodal stem segments having axillary bud, taken from
field-grown plant, showed bud-break within 15 days of culture on modified Murashige and Skoog (MS) (Physiol Plant 15:473–497,
1962) medium supplemented with 0.25 mg/l each of 6-benzylaminopurine and indole-3-acetic acid along with 15 mg/l adenine sulphate
(AdS). Regenerated shoots could be further multiplied on the same agarified morphogenetic medium in presence of 0.5 mg/l 2-chloroethyltrimethyl
ammonium chloride with increased concentration of AdS, i.e., 30 mg/l. A group of five shoots used as inoculum produced on
an average 4.98 new shoots per original shoot after 4 weeks of subculture. Shoots excised from cultures of proliferating shoots
were rooted in half-strength MS medium having 1 mg/l indole-3-propionic acid. In vitro rooted shoots—plantlets—grew luxuriantly
under field conditions and came to flowering after 10 months of transplantation. The genetic fidelity of in vitro-raised field-grown
plants and their mother plant was ascertained by random amplified polymorphic DNA markers. The protocol developed holds good
for in vitro cloning of C. serratum. 相似文献
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Nucleotide sequence and expression of the algE gene involved in alginate biosynthesis by Pseudomonas aeruginosa. 总被引:13,自引:0,他引:13
Alginate (Alg), a random polymer of mannuronic acid and glucuronic acid residues, is synthesized and secreted by Pseudomonas aeruginosa primarily during its infection of the lungs of cystic fibrosis patients. The molecular biology and biochemistry of the enzymatic steps leading to the production of the Alg precursor GDP-mannuronic acid have been elucidated, but the mechanism of polymer formation and export of Alg are not understood. We report the nucleotide sequence of a 2.4-kb DNA fragment containing the algE gene, previously designated alg76, encoding the AlgE protein (Mr 54,361) that is believed to be involved in these late steps of Alg biosynthesis. Expression of algE appears to occur from its own promoter. The promoter region contains several direct and inverted repeat sequences and shares structural similarity with promoters of several other alg genes from P. aeruginosa. In addition, the AlgE protein was overproduced from the tac promoter in P. aeruginosa. N-terminal amino acid sequence analysis showed that the polypeptide contains a signal peptide which is cleaved to form the mature protein during AlgE export from the cell cytoplasm. 相似文献