Whole-Genome Sequences of One Arthrobacter Strain and Three Pseudarthrobacter Strains Isolated from the Namib Desert

We report here the draft genome sequences of one Arthrobacter sp. strain (NamB2) and three Pseudarthrobacter sp. strains (NamE2, NamB4, and NamE5) isolated from topsoil in the Namib Desert, Namibia. The assemblies contain between 29 (NamB2) and 68 (NamE5) contigs >200 bp and range from 3.26 Mb (NamB2) to 4.03 Mb (NamE2). One plasmid was identified in Pseudarthrobacter sp. strain NamE5.

Evaluation of Single and Joint Toxicity of Perfluorinated Carboxylic Acids and Copper to Metal-Resistant Arthrobacter Strains

Perfluorocarboxylic acid compounds (PFCAs) and copper have been regarded as ubiquitous environmental contaminants in aquatic ecosystems worldwide. However, data on their possible joint toxic effects on microorganisms are still lacking. To study the combined effects of four PFCAs with different carbon chain lengths and copper, a series of experiments were conducted to explore the acute toxicity of these PFCAs in the absence and presence of copper on a metal-resistant Arthrobacter strain GQ-9 by microcalorimetry. The thermokinetic parameters, including growth rate constant (k), inhibitory ratio (I), and half inhibitory concentration (IC50), were calculated and compared using the data obtained from the power-time curves. Our work revealed that GQ-9 is more resistant to perfluorooctanoic acid (PFOA) than Escherichia coli. The single and joint toxicity of PFCAs with copper are dose- and carbon chain length-dependent. The longer the carbon chain length of PFCAs, the higher the toxicity. In addition, PFCAs interacted synergistically with copper. This work could provide useful information for the risk assessment of co-exposure to perfluorinated compounds and heavy metals in natural environments.