The Sinorhizobium meliloti insertion sequence (IS) element ISRm14 is related to a previously unrecognized IS element located adjacent to the Escherichia coli locus of enterocyte effacement (LEE) pathogenicity island

Schneiker-Bekel S, Kosier B, Pühler A, Selbitschka W. The Sinorhizobium meliloti insertion sequence (IS) element ISRm14 is related to a previously unrecognized IS element located adjacent to the Escherichia coli locus of enterocyte effacement (LEE) pathogenicity island. CURRENT MICROBIOLOGY. 1999;39(5):274-281.ISRm14 is 2695 basepairs (bp) in size and bordered by 22 bp imperfect inverted repeats (IRs). A 9-bp target sequence is duplicated upon ISRm14 transposition. The DNA strand that putatively encodes the transposase enzyme carries three open reading frames (ORFs) designated ORFs 1 to 3, which specify putative proteins of 15.9 kDa, 13.1 kDa, and 61.1 kDa, respectively. According to its structural characteristics, ISRm14 belongs to the recently proposed IS66 family of IS elements. The ORFs1 to 3 encoded putative proteins displayed significant similarities to ORFs of the previously unrecognized IS element ISEc8, which is inserted adjacent to the locus of enterocyte effacement (LEE) pathogenicity island of Escherichia coli EDL933. Analyses of the distribution of ISRm14 in a natural S. meliloti population showed its widespread occurrence in 66% of the strains tested with a copy number ranging from 1 to 6

THE INSERTION-SEQUENCE ELEMENT ISRM2011-2 BELONGS TO THE IS630-TC1 FAMILY OF TRANSPOSABLE ELEMENTS AND IS ABUNDANT IN RHIZOBIUM-MELILOTI

Selbitschka W, Arnold W, Jording D, KOSIER B, TORO N, Pühler A. THE INSERTION-SEQUENCE ELEMENT ISRM2011-2 BELONGS TO THE IS630-TC1 FAMILY OF TRANSPOSABLE ELEMENTS AND IS ABUNDANT IN RHIZOBIUM-MELILOTI. GENE. 1995;163(1):59-64.The insertion sequence (IS) element ISRm2011-2 of Rhizobium meliloti (Rm) is characterized by 19-bp imperfect terminal inverted repeats (three mismatches) and a size of 1053 bp. Upon transposition, ISRm2011-2 generates a putative target duplication of 2 bp. ISRm2011-2 carries two major overlapping open reading frames (ORFA and B) with a coding capacity of 135 and 201 amino acids (aa), respectively, A potential translational frameshifting window (5'-AAAAAAAG) is located in the overlapping region of both ORFs, The putative fusion product of both proteins, which probably represents the mature transposase, has a predicted molecular mass of 35.8 kDa and a pI of 10.5, Comparison of the deduced aa sequence of ORFA with database entries revealed homology to putative transposases of some IS elements of the IS3 family, as well as to eukaryotic transcription factors. The protein encoded by ORFB shows homology to transposases (Tps) of the recently proposed IS630-Tc1 family which includes Tps of both prokaryotic and eukaryotic transposable elements, Analyses of the distribution of ISRm2011-2 in natural Rm populations showed that this IS element is abundant in Rm strains

Analyse der Bildung und Diversitaet von symbiontischen und freilebenden N_2-fixierenden Mikrobenpopulationen in rekultivierten Boeden des Rheinischen Braunkohlereviers Schlussbericht

SIGLEAvailable from TIB Hannover: F01B1167+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Forschungszentrum Juelich GmbH (Germany). Projekttraeger Biologie, Energie, Oekologie (BEO)DEGerman

Symbiotic Plasmid Rearrangement in Rhizobium leguminosarum bv. viciae VF39SM

A rearrangement between the symbiotic plasmid (pRleVF39d) and a nonsymbiotic plasmid (pRleVF39b) in Rhizobium leguminosarum bv. viciae VF39 was observed. The rearranged derivative showed the same plasmid profile as its parent strain, but hybridization to nod, fix, and nif genes indicated that most of the symbiotic genes were now present on a plasmid corresponding in size to pRleVF39b instead of pRleVF39d. On the other hand, some DNA fragments originating from pRleVF39b now hybridized to the plasmid band at the position of pRleVF39d. These results suggest that a reciprocal but unequal DNA exchange between the two plasmids had occurred