TY - JOUR A1 - Basler, Georg A1 - Grimbs, Sergio A1 - Nikoloski, Zoran T1 - Optimizing metabolic pathways by screening for feasible synthetic reactions JF - Biosystems : journal of biological and information processing sciences N2 - Background: Reconstruction of genome-scale metabolic networks has resulted in models capable of reproducing experimentally observed biomass yield/growth rates and predicting the effect of alterations in metabolism for biotechnological applications. The existing studies rely on modifying the metabolic network of an investigated organism by removing or inserting reactions taken either from evolutionary similar organisms or from databases of biochemical reactions (e.g., KEGG). A potential disadvantage of these knowledge-driven approaches is that the result is biased towards known reactions, as such approaches do not account for the possibility of including novel enzymes, together with the reactions they catalyze. Results: Here, we explore the alternative of increasing biomass yield in three model organisms, namely Bacillus subtilis, Escherichia coil, and Hordeum vulgare, by applying small, chemically feasible network modifications. We use the predicted and experimentally confirmed growth rates of the wild-type networks as reference values and determine the effect of inserting mass-balanced, thermodynamically feasible reactions on predictions of growth rate by using flux balance analysis. Conclusions: While many replacements of existing reactions naturally lead to a decrease or complete loss of biomass production ability, in all three investigated organisms we find feasible modifications which facilitate a significant increase in this biological function. We focus on modifications with feasible chemical properties and a significant increase in biomass yield. The results demonstrate that small modifications are sufficient to substantially alter biomass yield in the three organisms. The method can be used to predict the effect of targeted modifications on the yield of any set of metabolites (e.g., ethanol), thus providing a computational framework for synthetic metabolic engineering. KW - Metabolic networks KW - Optimization KW - Mass-balanced reactions KW - Synthetic biology Y1 - 2012 U6 - https://doi.org/10.1016/j.biosystems.2012.04.007 SN - 0303-2647 VL - 109 IS - 2 SP - 186 EP - 191 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Gechev, Tsanko S. A1 - Hille, Jacques A1 - Woerdenbag, Herman J. A1 - Benina, Maria A1 - Mehterov, Nikolay A1 - Toneva, Valentina A1 - Fernie, Alisdair R. A1 - Müller-Röber, Bernd T1 - Natural products from resurrection plants: Potential for medical applications JF - Biotechnology advances : an international review journal ; research reviews and patent abstracts N2 - Resurrection species are a group of land plants that can tolerate extreme desiccation of their vegetative tissues during harsh drought stress, and still quickly often within hours regain normal physiological and metabolic functions following rehydration. At the molecular level, this desiccation tolerance is attributed to basal cellular mechanisms including the constitutive expression of stress-associated genes and high levels of protective metabolites present already in the absence of stress, as well as to transcriptome and metabolome reconfigurations rapidly occurring during the initial phases of drought stress. Parts of this response are conferred by unique metabolites, including a diverse array of sugars, phenolic compounds, and polyols, some of which accumulate to high concentrations within the plant cell. In addition to drought stress, these metabolites are proposed to contribute to the protection against other abiotic stresses and to an increased oxidative stress tolerance. Recently, extracts of resurrection species and particular secondary metabolites therein were reported to display biological activities of importance to medicine, with e.g. antibacterial, anticancer, antifungal, and antiviral activities, rendering them possible candidates for the development of novel drug substances as well as for cosmetics. Herein, we provide an overview of the metabolite composition of resurrection species, summarize the latest reports related to the use of natural products from resurrection plants, and outline their potential for medical applications. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). KW - Antibacterial KW - Anticancer KW - Antifungal KW - Antiviral KW - Natural product KW - Resurrection plant KW - Secondary metabolite KW - Synthetic biology Y1 - 2014 U6 - https://doi.org/10.1016/j.biotechadv.2014.03.005 SN - 0734-9750 SN - 1873-1899 VL - 32 IS - 6 SP - 1091 EP - 1101 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Messerschmidt, Katrin A1 - Hochrein, Lena A1 - Dehm, Daniel A1 - Schulz, Karina A1 - Mueller-Roeber, Bernd T1 - Characterizing seamless ligation cloning extract for synthetic biological applications JF - Analytical biochemistry : methods in the biological sciences N2 - Synthetic biology aims at designing and engineering organisms. The engineering process typically requires the establishment of suitable DNA constructs generated through fusion of multiple protein coding and regulatory sequences. Conventional cloning techniques, including those involving restriction enzymes and ligases, are often of limited scope, in particular when many DNA fragments must be joined or scar-free fusions are mandatory. Overlap-based-cloning methods have the potential to overcome such limitations. One such method uses seamless ligation cloning extract (SLiCE) prepared from Escherichia coli cells for straightforward and efficient in vitro fusion of DNA fragments. Here, we systematically characterized extracts prepared from the unmodified E. coli strain DH10B for SLiCE-mediated cloning and determined DNA sequence-associated parameters that affect cloning efficiency. Our data revealed the virtual absence of length restrictions for vector backbone (up to 13.5 kbp) and insert (90 bp to 1.6 kbp). Furthermore, differences in GC content in homology regions are easily tolerated and the deletion of unwanted vector sequences concomitant with targeted fragment insertion is straightforward. Thus, SLiCE represents a highly versatile DNA fusion method suitable for cloning projects in virtually all molecular. and synthetic biology projects. (C) 2016 Elsevier Inc. All rights reserved. KW - SLiCE KW - Seamless ligation cloning KW - Homologous recombination KW - Synthetic biology Y1 - 2016 U6 - https://doi.org/10.1016/j.ab.2016.05.029 SN - 0003-2697 SN - 1096-0309 VL - 509 SP - 24 EP - 32 PB - Elsevier CY - San Diego ER -