Azotobacter vinelandii is a soil bacterium related to the Pseudomonas genus that fixes nitrogen under aerobic conditions while simultaneously protecting nitrogenase from oxygen damage. In response to carbon availability, this organism undergoes a simple differentiation process to form cysts that are resistant to drought and other physical and chemical agents. Here we report the complete genome sequence of A. vinelandii DJ, which has a single circular genome of 5,365,318 bp. In order to reconcile an obligate aerobic lifestyle with exquisitely oxygen-sensitive processes, A. vinelandii is specialized in terms of its complement of respiratory proteins. It is able to produce alginate, a polymer that further protects the organism from excess exogenous oxygen, and it has multiple duplications of alginate modification genes, which may alter alginate composition in response to oxygen availability. The genome analysis identified the chromosomal locations of the genes coding for the three known oxygen-sensitive nitrogenases, as well as genes coding for other oxygen-sensitive enzymes, such as carbon monoxide dehydrogenase and formate dehydrogenase. These findings offer new prospects for the wider application of A. vinelandii as a host for the production and characterization of oxygen-sensitive proteins.

A search of the M1genome sequence, which includes 97% of the Myxococcus xanthus genes, identified 53 sequence homologs of 54 -dependent enhancer binding proteins (EBPs). A DNA microarray was constructed from the M1genome that includes those homologs and 318 other M. xanthus genes for comparison. To screen the developmental program with this array, an RNA extract from growing cells was compared with one prepared from developing cells at 12 h. Previous reporter studies had shown that M. xanthus has initiated development and has begun to express many developmentally regulated genes by 12 h. The comparison revealed substantial increases in the expression levels of 11 transcription factors that may respond to environmental stimuli. Six of the 53 EBP homologs were expressed at significantly higher levels at 12 h of development than during growth. Three were previously unknown genes, and they were inactivated to look for effects on fruiting body development. One knockout mutant produced fruiting bodies of abnormal shape that depended on the composition of the medium.

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Following an internal review of significant environmental risks in 2003, Rio Tinto developed, using a combination of in-house and external expertise, an ARD screening protocol to rank innate hazards at its mines and a second protocol to assess performance in key management areas during site-based risk reviews. Eight risk reviews were conducted in 2004 and another four in early 2005, at mines covering a wide range of commodities, operating methods and project stages. These reviews have proven successful in identifying and reducing ARD-related risks within Rio Tinto. Site-specific findings identified by these reviews are reported through corporate assurance processes with progress on agreed remedial actions being tracked semi-annually. Some common issues, covering aspects such as characterisation, groundwater monitoring and modelling, material segregation, cover design and flooding of workings, were identified at multiple sites. These have also been addressed by strengthening existing corporate environmental standards and guidance for ARD prediction and management. This paper summarizes the methodologies and the major findings of the first two years of the Rio Tinto program.