Nodulation of alfalfa by exoB mutants of Rhizobium meliloti occurred without root hair curling or infection thread formation. nod exoB double mutants had the same nodulation deficiency as single nod mutants. Therefore, all the known nod genes are involved in nodule induction by exoB mutants, which apparently occurs via intercellular invasion.

Femtosecond pump-probe absorption spectroscopy in tetrahydrofuran solution has been used to investigate the dynamics of a metalloid cluster compound {Ge9[Si(SiMe3)3]3}(-). Upon UV photoexcitation, the transients in the near-infrared spectral region showed signatures reminiscent of excess electrons in THF (bound or quasi-free) whereas in the visible part excited state dynamics of the cluster com...

Transformation of R factor RP4 and its derivative pRK290 from Escherichia coli to Rhizobium meliloti is reported. The efficiency of transformation was in the range of 10(-5) per viable cell. In addition, chromosomal DNA prepared from one R. meliloti strain resistant to streptomycin was transferred to the isoleucine-valine-requiring mutant susceptible to streptomycin.

A general tendency for additivity prevailed in recombination frequencies for two-point fine-structure mapping of 14 mutants in the C cistron of Rhizobium meliloti phage 16-3, with little evidence of any marker effect. Intracistronic three-point mapping indicated that double crossovers are rare. Deletion mapping indicated that the two- and three-point mapping data gave the correct order of the m...

Ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause lysis of these other bacteria. Based on the sequence of its small-subunit rRNA gene, E. adhaerens is related to Sinorhizobium spp. E. adhaerens ATCC 33499 did not nodulate Phaseolus vulgaris (bean) or Leucaena leucocephala, but with symbiotic plasmids from Rhizobium tropici CFN299 it formed nitrogen-fixing nodul...