The Shewanella Blogger

Hello Shewanella folks,

Here are a couple of new papers from the Shewanella Fed. I haven’t thoroughly read them yet, but there are some interesting findings nestled in each paper.

1.  McLean JS, Pinchuk GE, Geydebrekht OV, Bilskis CL, Zakrajsek BA, Hill EA, Saffarini DA, Romine MF, Gorby YA, Fredrickson JK, Beliaev AS.
Oxygen-dependent autoaggregation in Shewanella oneidensis MR-1.
Environ Microbiol. 2008 Apr 9 PMID: 18412550

2: Yang Y, Harris DP, Luo F, Wu L, Parsons AB, Palumbo AV, Zhou J.
Characterization of the Shewanella oneidensis Fur gene: roles in iron and acid
tolerance response.
BMC Genomics. 2008;9 Suppl 1:S11. PMID: 18366600

Happy reading!

Interesting paper on the tetraheme cytochrome has just been published. Authors show that the CymA cytochrome has iron reductase activity when expressed in E. coli. They propose that this has given E. coli the ability to respire iron(III). That is, E. coli can conserve energy from reducing iron and grow on it too. This is normally not the case. Here is the link to the paper in Pubmed:

Dissimilatory iron reduction in Escherichia coli: identification of CymA of Shewanella oneidensis and NapC of E. coli as ferric reductases.

Gescher JS, Cordova CD, Spormann AM.

http://www.ncbi.nlm.nih.gov/pubmed/18394146?dopt=Abstract

Stolz and colleagues (Duquesne University) published a recent paper on the characterization of an arsenate respiring bacterium isolated from the Ohio River. The microbe, Alkaliphilus oremlandii strain OhILAs, was named in honor of the grandfather of arsenic-respiring bacteria Dr. Ron Oremland. Here is the PubMed link:

Fisher et al. (2008) Transformation of Inorganic and Organic Arsenic by Alkaliphilus oremlandii sp. nov. Strain OhILAs. Ann N Y Acad Sci. 1125:230-41.

The strain is gram positive and appears to tolerate and grow quite well on arsenic. Definitely a paper we should all read.

I thought this was an April Fools joke. However, according to a recent article in Environmental Health Perspectives, arsenic exposure in drinking water is a risk factor for erectile dysfunction. Here is the link to the abstract:

Fang et al. “Risk of Erectile Dysfunction Induced by Arsenic Exposure through Well Water Consumption in Taiwan” Environmental Health Perspectives Volume 116, Number 4, April 2008

Linking arsenic to ED seems crazy but in the intro the authors mention that ED is linked to cardiovascular diseases, which is also influenced by arsenic exposure too. If you make the connection between arsenic and cardiovascular disease therefore, ED could be another symptom of arsenic exposure. We’ll see how this plays out in long run.