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Marburg an der Lahn, Germany

Paulick A.,Max Planck Institute For Terrestrische Mikrobiologie | Paulick A.,Research Center for Synthetic Microbiology | Delalez N.J.,University of Oxford | Delalez N.J.,University of Warwick | And 7 more authors.
Molecular Microbiology | Year: 2015

The bacterial flagellar motor is an intricate nanomachine which converts ion gradients into rotational movement. Torque is created by ion-dependent stator complexes which surround the rotor in a ring. Shewanella oneidensisMR-1 expresses two distinct types of stator units: the Na+-dependent PomA4B2 and the H+-dependent MotA4B2. Here, we have explored the stator unit dynamics in the MR-1 flagellar system by using mCherry-labeled PomAB and MotAB units. We observed a total of between 7 and 11 stator units in each flagellar motor. Both types of stator units exchanged between motors and a pool of stator complexes in the membrane, and the exchange rate of MotAB, but not of PomAB, units was dependent on the environmental Na+-levels. In 200mM Na+, the numbers of PomAB and MotAB units in wild-type motors was determined to be about 7:2 (PomAB:MotAB), shifting to about 6:5 without Na+. Significantly, the average swimming speed of MR-1 cells at low Na+ conditions was increased in the presence of MotAB. These data strongly indicate that the S.oneidensis flagellar motors simultaneously use H+ and Na+ driven stators in a configuration governed by MotAB incorporation efficiency in response to environmental Na+ levels. Shewanella oneidensis MR-1 possesses two disting stator units, the Na+-dependent PomAB (blue) and the H+-dependent MotAB (red), to drive rotation of the single polar flagellum. Here we show that the stator/motor configuration is dynamically adjusted in response to changing environmental sodium levels and that the S. oneidensis MR-1 flagellum is likely driven by a hybrid motor consisting of Na+- and H+-dependent stators. © 2015 John Wiley & Sons Ltd.

Robledo M.,University of Salamanca | Robledo M.,Research Center for Synthetic Microbiology | Rivera L.,University of Salamanca | Jimenez-Zurdo J.I.,CSIC - Experimental Station of El Zaidin | And 6 more authors.
Microbial Cell Factories | Year: 2012

Background: The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2) that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii.Results: ANU843 celC mutants lacking (ANU843ΔC2) or overproducing cellulase (ANU843C2+) produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843ΔC2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta.Conclusions: Our results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this " building material" seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates. © 2012 Robledo et al.; licensee BioMed Central Ltd.

Leinweber M.,University of Marburg | Leinweber M.,Research Center for Synthetic Microbiology | Fober T.,University of Marburg | Strickert M.,University of Marburg | And 6 more authors.
IEEE Transactions on Knowledge and Data Engineering | Year: 2016

CavBase is a database containing information about the three-dimensional geometry and the physicochemical properties of putative protein binding sites. Analyzing CavBase data typically involves computing the similarity of pairs of binding sites. In contrast to sequence alignment, however, a structural comparison of protein binding sites is a computationally challenging problem, making large scale studies difficult or even infeasible. One possibility to overcome this obstacle is to precompute pairwise similarities in an all-against-all comparison, and to make these similarities subsequently accessible to data analysis methods. Pairwise similarities, once being computed, can also be used to equip CavBase with a neighborhood structure. Taking advantage of this structure, methods for problems such as similarity retrieval can be implemented efficiently. In this paper, we tackle the problem of performing an all-against-all comparison using CavBase, consisting of more than 200,000 protein cavities, by means of parallel computation and cloud computing techniques. We present the conceptual design and technical realization of a large-scale study to create a similarity database called CavSimBase. We illustrate how CavSimBase is constructed, is accessed, and is used to answer biological questions by data analysis and similarity retrieval. © 1989-2012 IEEE.

Hempel F.,Research Center for Synthetic Microbiology | Lau J.,University of Marburg | Klingl A.,Research Center for Synthetic Microbiology | Maier U.G.,Research Center for Synthetic Microbiology | Maier U.G.,University of Marburg
PLoS ONE | Year: 2011

Microalgae are thought to offer great potential as expression system for various industrial, therapeutic and diagnostic recombinant proteins as they combine high growth rates with all benefits of eukaryotic expression systems. Moreover, microalgae exhibit a phototrophic lifestyle like land plants, hence protein expression is fuelled by photosynthesis, which is CO2-neutral and involves only low production costs. So far, however, research on algal bioreactors for recombinant protein expression is very rare calling for further investigations in this highly promising field. In this study, we present data on the expression of a monoclonal human IgG antibody against the Hepatitis B surface protein and the respective antigen in the diatom Phaeodactylum tricornutum. Antibodies are fully-assembled and functional and accumulate to 8.7% of total soluble protein, which complies with 21 mg antibody per gram algal dry weight. The Hepatitis B surface protein is functional as well and is recognized by algae-produced and commercial antibodies. © 2011 Hempel et al.

Hempel F.,Research Center for Synthetic Microbiology | Bozarth A.S.,University of Marburg | Lindenkamp N.,University of Munster | Klingl A.,Research Center for Synthetic Microbiology | And 5 more authors.
Microbial Cell Factories | Year: 2011

Background: Poly-3-hydroxybutyrate (PHB) is a polyester with thermoplastic properties that is naturally occurring and produced by such bacteria as Ralstonia eutropha H16 and Bacillus megaterium. In contrast to currently utilized plastics and most synthetic polymers, PHB is biodegradable, and its production is not dependent on fossil resources making this bioplastic interesting for various industrial applications.Results: In this study, we report on introducing the bacterial PHB pathway of R. eutropha H16 into the diatom Phaeodactylum tricornutum, thereby demonstrating for the first time that PHB production is feasible in a microalgal system. Expression of the bacterial enzymes was sufficient to result in PHB levels of up to 10.6% of algal dry weight. The bioplastic accumulated in granule-like structures in the cytosol of the cells, as shown by light and electron microscopy.Conclusions: Our studies demonstrate the great potential of microalgae like the diatom P. tricornutum to serve as solar-powered expression factories and reveal great advantages compared to plant based production systems. © 2011 Hempel et al; licensee BioMed Central Ltd.

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