Jonathan D. Todd

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Rhizobium leguminosarum is an α-proteobacterial N2-fixing symbiont of legumes that has been the subject of more than a thousand publications. Genes for the symbiotic interaction with plants are well studied, but the adaptations that allow survival and growth in the soil environment are poorly understood. We have sequenced the genome of R. leguminosarum(More)
The marine alphaproteobacterium Roseovarius nubinhibens ISM can produce the gas dimethyl sulfide (DMS) from dimethylsulfoniopropionate (DMSP), a widespread secondary metabolite that occurs in many phytoplankton. Roseovarius possesses a novel gene, termed dddP, which when cloned, confers on Escherichia coli the ability to produce DMS. The DddP polypeptide is(More)
A bacterium in the genus Halomonas that grew on dimethylsulfoniopropionate (DMSP) or acrylate as sole carbon sources and that liberated the climate-changing gas dimethyl sulfide in media containing DMSP was obtained from the phylloplane of the macroalga Ulva. We identified a cluster that contains genes specifically involved in DMSP catabolism (dddD, dddT)(More)
The alpha-proteobacterium Sulfitobacter EE-36 makes the gas dimethylsulfide (DMS) from dimethylsulfoniopropionate (DMSP), an abundant antistress molecule made by many marine phytoplankton. We screened a cosmid library of Sulfitobacter for clones that conferred to other bacteria the ability to make DMS. One gene, termed dddL, was sufficient for this(More)
The compatible solute dimethylsulphoniopropionate (DMSP) has important roles in marine environments. It is an anti-stress compound made by many single-celled plankton, some seaweeds and a few land plants that live by the shore. Furthermore, in the oceans it is a major source of carbon and sulphur for marine bacteria that break it down to products such as(More)
In wild-type Rhizobium leguminosarum, the sitABCD operon specifies a Mn(2+) transporter whose expression is severely reduced in cells grown in the presence of this metal. Mutations in the R. leguminosarum gene, mur (manganese uptake regulator), whose product resembles the Fur transcriptional regulator, cause high-level expression of sitABCD in the presence(More)
We used comparative genomics to investigate the distribution of conserved DNA-binding motifs in the regulatory regions of genes involved in iron and manganese homeostasis in alpha-proteobacteria. Combined with other computational approaches, this allowed us to reconstruct the metal regulatory network in more than three dozen species with available genome(More)
Dimethyl sulfide (DMS) is a key compound in global sulfur and carbon cycles. DMS oxidation products cause cloud nucleation and may affect weather and climate. DMS is generated largely by bacterial catabolism of dimethylsulfoniopropionate (DMSP), a secondary metabolite made by marine algae. We demonstrate that the bacterial gene dddD is required for this(More)
Mutations in a Rhizobium leguminosarum gene, rirA (rhizobial iron regulator), caused high-level, constitutive expression of at least eight operons whose transcription is normally Fe-responsive and whose products are involved in the synthesis or uptake of siderophores, or in the uptake of haem or of other iron sources. Close homologues of RirA exist in other(More)
The alpha-proteobacteria include several important genera, including the symbiotic N(2)-fixing "rhizobia", the plant pathogen Agrobacterium, the mammalian pathogens Brucella, Bartonella as well as many others that are of environmental or other interest--including Rhodobacter, Caulobacter and the hugely abundant marine genus Pelagibacter. Only a few(More)