In this work we apply a bioinformatics approach to determine the most important enzymes of the metabolic network of Eucalyptus to determine the coverage of the genome in the FORESTS library. We conclude that the library does not cover completely the metabolism of the organism. However, some important pathways could be analyzed, especially the lignin synthesis. We found that four of the most important enzymes predicted are involved in this pathway.Key words: Eucalyptus, metabolism. The genome sequences of several organisms are available (Kanehisa and Goto, 2000) currently and the extraction of relevant physiological information from these data is a major challenge. The metabolic networks reconstructed from the annotated genomes provide an abundance of information for exploration with bioinformatics (Karp et al., 1999). In this article we apply a recently developed graph analysis of metabolism that predicts important enzymes of the metabolic network of Eucalyptus. Data were obtained from the non-public database of the Eucalyptus Genome Sequencing Project Consortium (FORESTS, https://forests.esalq.usp.br/) that contains approximately 100,000 expressed sequence tags (ESTs) of this plant.Cellular metabolism is a complex network of biochemical reactions catalyzed by specialized proteins called enzymes. The reactions are organized in modules called metabolic maps with specific catabolic or anabolic functions. The complete set of metabolic maps forms the metabolic network.An exponentially growing number of organisms have sequenced genomes (Devos and Valencia, 2001), and assuming that the annotated proteins are expressed, we can reconstruct the metabolic network of the organism (Karp et al., 1999).The investigation of the influence of enzymes on the network is a critical issue for the bioengineering and pharmaceutical industry since they can be targets for drugs (Karp et al., 1999) or they can be genetically engineered to change the metabolic output of specific metabolites (Edwards and Palsson, 1997). Our approach investigates the static structure of the components of the network to infer causal and physiological relationships. In a previous work we applied our method to Escherichia coli, whose metabolism has been studied in depth, and found a strong correlation between the damage an enzyme causes to the network and its essentiality , thus showing the predictive power the method has for determining important enzymes. In this work we apply this method to the genome of Eucalyptus that is an important commercial source of wood and cellulose. In particular, there is a great deal of interest in the bioengineering of plants involving the metabolic pathways of cellulose and lignin to generate genetically modified organisms with enhanced production of cellulose and decreased production of lignin.In our method we have introduced a new quantitative criterion for enzyme importance: the damage its removal causes to the metabolic network . In the absence of complete information about kinetic parameters and the influence of t...

O aumento da utilização das redes de computadores e o crescimento dos serviços por elas suportados têm causado um aumento no número de incidentes de segurança. Os sistemas de detecção de intrusão (IDS) têm sido usados, nesse contexto, para identificar atividades maliciosas como sondagens e ataques. No caso dos IDSs baseados em assinatura, é preciso descrever essas atividades para que eles sejam capazes de monitorar a sua ocorrência. A maioria dos sistemas, no entanto, não oferece flexibilidade a esse processo de especificação, além de exigir a utilização de notações em baixo nível. Esse trabalho apresenta um sistema de detecção de intrusão, o E-Sentry+, que aborda esse problema ao explorar uma linguagem em alto nível para a representação de assinaturas.