02088nas a2200217   4500008004100000245006100041210006100102300001200163490000800175520132100183653013101504653002201635653001601657100001801673700001601691700001601707700001201723700001601735700001301751856010601764       2007                        eng d00aStructural analyses of a hypothetical minimal metabolism0 aStructural analyses of a hypothetical minimal metabolism  a1751-620 v3623 aBy integrating data from comparative genomics and large-scale deletion studies, we previously proposed a minimal gene set comprising 206 protein-coding genes. To evaluate the consistency of the metabolism encoded by such a minimal genome, we have carried out a series of computational analyses. Firstly, the topology of the minimal metabolism was compared with that of the reconstructed networks from natural bacterial genomes. Secondly, the robustness of the metabolic network was evaluated by simulated mutagenesis and, finally, the stoichiometric consistency was assessed by automatically deriving the steady-state solutions from the reaction set. The results indicated that the proposed minimal metabolism presents stoichiometric consistency and that it is organized as a complex power-law network with topological parameters falling within the expected range for a natural metabolism of its size. The robustness analyses revealed that most random mutations do not alter the topology of the network significantly, but do cause significant damage by preventing the synthesis of several compounds or compromising the stoichiometric consistency of the metabolism. The implications that these results have on the origins of metabolic complexity and the theoretical design of an artificial minimal cell are discussed.10a*Cell Physiological Phenomena Cells/*metabolism Cluster Analysis *Computer Simulation *Metabolic Networks and Pathways *Models10aBiological Models10aStatistical1 aGabaldón, T.1 aPeretó, J.1 aMontero, F.1 aGil, R.1 aLatorre, A.1 aMoya, A.  uhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=1751002201950nas a2200229   4500008004100000245009500041210006900136300001000205490000700215520116100222653001401383653005301397653002801450653003701478100001801515700001501533700001901548700001501567700001901582700001301601856010601614       2001                        eng d00aPhylogenetic analysis of viroid and viroid-like satellite RNAs from plants: a reassessment0 aPhylogenetic analysis of viroid and viroidlike satellite RNAs fr  a155-90 v533 aThe proposed monophyletic origin of a group of subviral plant pathogens (viroids and viroid-like satellite RNAs), as well as the phylogenetic relationships and the resulting taxonomy of these entities, has been recently questioned. The criticism comes from the (apparent) lack of sequence similarity among these RNAs necessary to reliably infer a phylogeny. Here we show that, despite their low overall sequence similarity, a sequence alignment manually adjusted to take into account all the local similarities and the insertions/deletions and duplications/rearrangements described in the literature for viroids and viroid-like satellite RNA, along with the use of an appropriate estimator of genetic distances, constitutes a data set suitable for a phylogenetic reconstruction. When the likelihood-mapping method was applied to this data set, the tree-likeness obtained was higher than that corresponding to a sequence alignment that does not take into consideration the local similarities. In addition, bootstrap analysis also supports the major groups previously proposed and the reconstruction is consistent with the biological properties of this RNAs.10aEvolution10aMolecular *Phylogeny Plant Viruses/*genetics RNA10aSatellite/*genetics RNA10aViral/genetics Viroids/*genetics1 aElena, S., F.1 aDopazo, J.1 ade la Pena, M.1 aFlores, R.1 aDiener, T., O.1 aMoya, A.  uhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11479686