• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1123-1126
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• 2011

The IncP plasmid R995 has been a useful self-transmissible, broad-host-range vector for a number of applications including the recombinase/conjugation-based cloning of large genomic DNA segments. However, R995 derivatives (or related plasmids) expressing a wide range of different resistance markers and Flp recombinase target sites do not exist in the literature. In addition, documented strategies for applying such plasmids in cloning applications that take advantage of conjugation for the convenient isolation and recovery of constructs are extremely limited. Here, we report a new series of R995 plasmids with alternative markers to increase options for applications in backgrounds already expressing resistance to a particular antibiotic(s). These R995 plasmids have been engineered to contain FRT sites that can be used for recombinase-based cloning. We demonstrate the utility of this approach by cloning 20 kb regions from the Salmonella Typhimurium and Escherichia coli genomes and by cloning DNA from an exogenous plasmid source. To our knowledge, this represents the first systematic engineering of an intact, self-transmissible IncP plasmid with a series of alternative antibiotic markers and FRT sites.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.181-187
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• 1988

Using a Tn5-Mob system, pEA9 was characterized as a self-transmissible plasmid carrying a kanamycin resistance marker. The self-transfer frequencies of pEA9 varied greatly depending on pH values. The transfer frequency was about $4\times 10^{-5}$ at pH 5, that was 10 times higher than one at pH 6.5. With a helper plasmid, transfer frequencies were increased about $10^{4}$ times than the frequencies obtained without it.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.28-31
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• 1998

Nodule development was regulated partially by host plant factors originating in the shoots and roots. This study was performed to identify the origin of the factors regulating nodulation in supernodulating soybean (Glycine max [L.] Merr.) mutant 'SS2-2' which was isolated recently from ethyl methanesulfonate (EMS) mutagenesis of 'Sinpaldalkong 2'. Self- and reciprocal-grafts were made among three soybean genotypes which consisted of two supernodulating mutants, SS2-2 and 'nts 382', and a normal nodulating Sinpaldalkong 2. Self-grafted supernodulating mutants were characterized by greater nodule number, nodule dry weight, and $C_2$H$_2$ reduction activity than self-grafted wild types. They were also characterized by relatively higher nodule to root dry weight. Significant shoot genotypic effects were observed on nodule number, nodule dry weight, and $C_2\;H_2$ reduction activity per plant, whereas varying root genotypes had no effects. From this result, it is surmised that supernodulating characters are controlled by a graft-transmissible shoot factor, and mutant SS2-2 may have similar nodulation mechanism to the former supernodulating nts 382. In all grafts, both supernodulating mutants and Sinpaldalkong 2 maintained the similar balance between above ground and below ground parts regardless of significant differences in partitioning of dry matter into root and nodule between supernodulating mutants and Sinpaldalkong 2.