Here is a very recent publication in J. Bact. The authors show that Shewanella oneidensis MR-1 has two adenylate cyclases that are essential to anaerobic respiraiton in Shewanella. These are the same cya’s as shown in the arsenate respiring Shewanella, strain ANA-3. The authors also report on transcriptome analysis of crp and adenylate cyclase mutants. This is a solid paper with interesting results. Here is the Pubmed link:
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Archived Posts from this Category
May 5, 2009
Another paper on cAMP, crp, and adenylate cyclases in Shewanella
Posted by shewanella under General, Regulation[4] Comments
January 28, 2009
It’s been a long time since my last post. A lot has happened since then in the land of Shewanella. I’ve included a couple of links to recent Shewanella publications. One in particular is the identification of adenylate cyclases that are involved in anaerobic respiration and showing that cAMP-CRP regulates arsenate respiration pathway. The work was done in Shewanella sp. ANA-3, which is slightly different than MR-1; ANA-3 can also respire arsenate. The other paper that might be of interest to Shewanella folks is the use of proteomics to characterize a regulator in MR-1 that might be involved in chromate transformation.
Comparative Temporal Proteomics of a Response Regulator (SO2426)-Deficient Strain and Wild-Type Shewanella oneidensis MR-1 During Chromate Transformation.
Chourey K, Thompson MR, Shah M, Zhang B, Verberkmoes NC, Thompson DK, Hettich RL.
J Proteome Res. 2009 Jan 2;8(1):59-71.
PMID: 19118451 [PubMed - as supplied by publisher]
Functional roles of arcA, etrA, cyclic AMP (cAMP)-cAMP receptor protein, and cya in the arsenate respiration pathway in Shewanella sp. strain ANA-3.
Murphy JN, Durbin KJ, Saltikov CW.
J Bacteriol. 2009 Feb;191(3):1035-43. Epub 2008 Dec 5.
PMID: 19060154 [PubMed - in process]
October 25, 2008
Here are a couple of Shewanella papers that I’ve got on my “to read list”:
Title: Direct involvement of type II secretion system in extracellular translocation of Shewanella oneidensis outer membrane cytochromes MtrC and OmcA
Author(s): Shi, L; Deng, S; Marshall, MJ; Wang, ZM; Kennedy, DW; Dohnalkova, AC; Mottaz, HM; Hill, EA; Gorby, YA; Beliaev, AS; Richardson, DJ; Zachara, JM; Fredrickson, JK
Source: JOURNAL OF BACTERIOLOGY 190 (15):5512-5516 2008
Abstract: MtrC and OmcA are cell surface-exposed lipoproteins important for reducing solid metal oxides. Deletions of type II secretion system (T2SS) genes reduced their extracellular release and their accessibility to the proteinase K treatment, demonstrating the direct involvement of T2SS in translocation of MtrC and OmcA to the bacterial cell surface.
Title: Expression of chromate resistance genes from Shewanella sp strain ANA-3 in Escherichia coli
Author(s): Aguilar-Barajas, E; Paluscio, E; Cervantes, C; Rensing, C
Source: FEMS MICROBIOLOGY LETTERS 285 (1):97-100 2008
Abstract: The plasmidic chromate resistance genes chrBAC from Shewanella sp. strain ANA-3 were transferred to Escherichia coli. Expression of chrA alone, on a high- or low-copy number plasmid, conferred increased chromate resistance. In contrast, expression of the complete operon chrBAC on a high-copy number plasmid did not result in a significant increase in resistance, although expression on a low-copy number plasmid made the cells up to 10-fold more resistant to chromate. The chrA gene also conferred increased chromate resistance when expressed in Pseudomonas aeruginosa. The chrR gene from the P. aeruginosa chromosome was necessary for full chromate resistance conferred by chrA. A diminished chromate uptake in cells expressing the chrA gene suggests that chromate resistance is due to chromate efflux.
August 1, 2008
I just learned about a really intriguing study about how Shewanella accesses iron(III) from solid phase iron oxide. The study used a novel electrochemical method to detect Fe(III) complexed with an organic ligand secreted by Shewanella putrefaciens strain 200. Controls showed that this ligand is secreted by Shewanella and not an artifact of dead cells or growth medium effects. The authors also discuss that the ligand is not the hydroxamate-type siderophore that Shewanella putrefaciens (strain 200) is known to secrete under aerobic conditions only. It will be very interesting to see what the nature of this Fe(III) ligand is.
Author(s): Taillefert, M (Taillefert, Martial); Beckler, JS (Beckler, Jordon S.); Carey, E (Carey, Elizabeth); Burns, JL (Burns, Justin L.); Fennessey, CM (Fennessey, Christine M.); DiChristina, TJ (DiChristina, Thomas J.)
Source: JOURNAL OF INORGANIC BIOCHEMISTRY, 101 (11-12): 1760-1767 NOV 2007
Abstract: The mechanism of Fe(III) reduction was investigated using voltarnmetric techniques in anaerobic incubations of Shewanella putrefaciens strain 200 supplemented with Fe(III) citrate or a suite of Fe(III) oxides as terminal electron acceptor. Results indicate that organic complexes of Fe(III) are produced during the reduction of Fe(III) at rates that correlate with the reactivity of the Fe(III) phase and bacterial cell density. Anaerobic Fe(III) solubilization activity is detected with either Fe(III) oxides or Fe(III) citrate, suggesting that the organic ligand produced is strong enough to destabilize Fe(III) from soluble or solid Fe(III) substrates. Results also demonstrate that Fe(III) oxide dissolution is not controlled by the intrinsic chemical reactivity of the Fe(III) oxides. Instead, the chemical reaction between the endogenous organic ligand is only affected by the number of reactive surface sites available to S. putrefaciens. This report describes the first application of voltarnmetric techniques to demonstrate production of soluble organic-Fe(III) complexes by any Fe(III)-reducing microorganism and is the first report of a Fe(Ill)-solubilizing ligand generated by a metal-reducing member of the genus Shewanella. (c) 2007 Elsevier Inc. All rights reserved.
July 15, 2008
Shewanella is a very interesting genus to work with. It is super easy to grow. Some people call it the E. coli of the environment. We routinely grow strains on LB agar at 30˚C. It should only take overnight for colonies to form. Similarly, LB liquid cultures take overnight to grow and can get up to 5-7 x 10^9 cells/ml. A second thing I like about Shewanella is that the organism is pretty straightforward to genetically manipulate. Most tools used in E. coli can also be used with Shewanella. Electroporation is tough but supposedly not impossible. We use a conjugation method and a special E. coli donor strain that has a mutation in the dapE gene. Thus the E. coli needs diaminopimelic acid to grow (part of the cell wall). Keep DAP around when doing plate conjugation reactions with E. coli to Shewanella and then plate out on antibiotic plates without DAP. The one bad thing we found with our Shewanella strain species ANA-3 is ampicillin resistance. This is a pain because we can’t use Amp selection with our strain. However, it should be easy to knockout the amp gene but we haven’t gotten around to doing this. That’s it for part I of why I like Shewanella.
Cheers.
Chad
July 9, 2008
Hello folks,
Here is a very recent review article on Shewanella. Should be an interesting read.
Towards environmental systems biology of Shewanella by Fredrickson et al. Nat. Rev. Microbiol
Bacteria of the genus Shewanella are known for their versatile electron-accepting capacities, which allow them to couple the decomposition of organic matter to the reduction of the various terminal electron acceptors that they encounter in their stratified environments. Owing to their diverse metabolic capabilities, shewanellae are important for carbon cycling and have considerable potential for the remediation of contaminated environments and use in microbial fuel cells. Systems-level analysis of the model species Shewanella oneidensis MR-1 and other members of this genus has provided new insights into the signal-transduction proteins, regulators, and metabolic and respiratory subsystems that govern the remarkable versatility of the shewanellae.
