Chlamydiae are obligate intracellular pathogens that cause several serious conditions within the human host. Many of the symptoms associated with infection are thought to stem from the development of aberrant, or persistent, chlamydiae. Factors leading to chlamydial persistence include deprivation of amino acids, the release of certain cellular factors, or...
We have used the sequence-specific endonucleases Eco RI, Sma I,
Bam HI, Hsu I and Hae III as identification tools in following the
conjugal transfer of the well studied R plasmids Sa, R388, RP4 and R6K.
Transfers were both intergenus and intragenus. Plasmid fingerprints
were generated from both single and...
The effect of carbon source, nitrogen source, and amino acid
starvation on the accumulation of guanosine tetraphosphate.and RNAand
protein synthesis in Rhizobium meliloti are described in this report.
An accumulation of ppGpp and a decrease in the rate of RNA and
protein synthesis were observed in response to nitrogen source...
Agrobacterium tumefaciens, the causative agent of crown gall
disease, does not readily infect commercial varieties of alfalfa (Medicago sativa). Cloned virulence genes from the megaplasmid pTiBo542 have
been shown to enhance Agrobacterium host range and infectivity on
dicotyledonous plants. To obtain a gene transfer system for commercial
alfalfa cultivars, an...
The transcriptional promoter sequences for the Rhizobium meliloti
nitrogen fixation genes nifA and nifB were cloned to a β-galactosidase gene
fusion plasmid vector and transferred by homologous recombination to a
specialized transducing phage. The promoter fusions were then transduced
to a recombination deficient strain of Escherichia coli as single-copy
lysogens...