Emergy evaluation for decision-making in complex multifunctional farming systems.

In a montado farm, commonly found in the South Portugal, human activities benefit from important fluxes of renewable resources. In this study, traditional economic and emergy evaluations are compared to determine their potential contributions to understanding this complex system and applied to a case study of a farm. This allows us to determine how each method values local natural resources and purchased factors of production and services in an empirical context. Results show that the montado farm has a renewable component evaluated at 27% of the total social costs of the system and that the work of natural resources is undervalued in economic budget accounting. Economic evaluation's relative value of purchased factors and services is three and half times higher than their emergy share. We propose that complementing economic budget accounting with emergy accounting provides a benchmark to evaluate the environmental contribution to agricultural and farming systems. In this way, factors external to markets can be evaluated for farming systems, bringing to economic analysis a full evaluation of resources, including the bio-geophysical system's contributions to wealth, enlarging total economic value of resources with a donor perspective enabling a better informed and comprehensive accounting to attain sustainable economic decisions and public policies.

Doença inflamatória intestinal com eritema nodoso como manifestação inicial ­ dois casos clínicos / Inflammatory bowel disease with erythema nodosum as the initial manifestation ­ two clinical cases

OBJETIVOS: Descrever dois casos de doença inflamatória intestinal cujo diagnóstico foi precedido pelo surgimento de eritema nodoso e alertar para essa manifestação extraintestinal como forma de apresentação inicial da doença. DESCRIÇÃO DOS CASOS: Dois adolescentes de 12 e 15 anos recorreram ao serviço de urgência de Pediatria por eritema nodoso acompanhado de anorexia e perda de peso. Os exames auxiliares de diagnóstico disponíveis foram sugestivos de doença crônica inflamatória e a ecografia abdominal sugestiva de doença inflamatória intestinal. O diagnóstico de doença de Crohn foi confirmado após realização de endoscopia digestiva alta e colonoscopia total com biópsias. CONCLUSÕES: O eritema nodoso pode ser a forma de apresentação de doenças potencialmente graves com terapêuticas bem estabelecidas e implicações prognósticas. Na criança ou adolescente com eritema nodoso o índice de suspeição de doença inflamatória intestinal deve ser elevado, embora devam ser considerados outros diagnósticos diferenciais. A importância do diagnóstico precoce na doença inflamatória intestinal em idade pediátrica consiste na oportunidade terapêutica e nas complicações específicas dessa faixa etária, como déficit de crescimento, que ocorre mais frequentemente na doença de Crohn.

AIMS: To describe two cases of inflammatory bowel disease whose diagnosis was preceded by the appearance of erythema nodosum and to alert to this extra-intestinal manifestation as the initial presentation of the disease. CASES DESCRIPTION: Two adolescents of 12 and 15 years of age were referred to the pediatrics emergency department because of erythema nodosum accompanied by anorexia and weight loss. The available diagnostic tests were suggestive of chronic inflammatory disease and the abdominal ultrasound was suggestive of inflammatory bowel disease. The diagnosis of Crohn's disease was confirmed after completion of upper digestive endoscopy and total colonoscopy with biopsies. CONCLUSIONS: Erythema nodosum may be the form of presentation of potentially serious diseases with well established therapies and prognostic implications. In children or adolescents with erythema nodosum, the index of suspicion of inflammatory bowel disease should be high, although other differential diagnoses should be considered. The importance of early diagnosis of inflammatory bowel disease in pediatric age refers to the therapeutic opportunity and specific complications in this age group, as growth disturbance, which occurs more frequently in Crohn's disease.

HIV-1 Vif protein blocks the cytidine deaminase activity of B-cell specific AID in E. coli by a similar mechanism of action.

HIV-1 Vif protein protects viral replication in non-permissive cells by inducing degradation of APOBEC3G via ubiquitination and proteasomal pathway, although new studies indicate a putative role in Vif's direct inhibition of APOBEC3G. APOBEC3G is member of a homologous family of proteins with cytidine deaminase activity expressed with characteristic tissue specificity, that in humans consist of APOBEC1, APOBEC2, APOBEC3A-H, APOBEC4 and the activation-induced deaminase (AID), a B lymphoid protein necessary for somatic hypermutation, gene conversion and class switch recombination. In this work we show that Vif can counteract AID's activity in E. coli in absence of specific eukaryotic co-factors necessary for AID induced somatic hypermutation, gene conversion and to stimulate class switch recombination in B-cells. We show that AID inhibition is mediated by a direct protein-protein interaction via unique amino acid D118 an homologous mutant responsible for the species-specific restriction of HIV-1 Vif protein existent for APOBEC3G. These results raise the hypothesis that Vif related proteins can act as a broad inhibitor of deaminase activity. Moreover as AID and Vif evolved in different cellular environments, these results may indicate that Vif related proteins might mimic cellular factors that interact with a structural conserved domain of cytidine deaminases during evolution.

HIV-1 Vif can directly inhibit apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G-mediated cytidine deamination by using a single amino acid interaction and without protein degradation.

The human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G), also known as CEM-15, is a host-cell factor involved in innate resistance to retroviral infection. HIV-1 viral infectivity factor (Vif) protein was shown to protect the virus from APOBEC3G-mediated viral cDNA hypermutation. The mechanism proposed for protection of the virus by HIV-1 Vif is mediated by APOBEC3G degradation through ubiquitination and the proteasomal pathway. Here we show that in Escherichia coli the APOBEC3G-induced cytidine deamination is inhibited by expression of Vif without depletion of deaminase. Moreover, inhibition of deaminase-mediated bacterial hypermutation is dependent on a single amino acid substitution D128K that renders APOBEC3G resistant to Vif inhibition. This single amino acid was elegantly proven by other authors to determine species-specific sensitivity. Our results show that in bacteria this single amino acid substitution controls Vif-dependent blocking of APOBEC3G that is dependent on a strong protein interaction. The C-terminal region of Vif is responsible for this strong protein-protein interaction. In conclusion, our experiments suggest a complement to the model of Vif-induced degradation of APOBEC3G by bringing to relevance that deaminase inhibition can also result from a direct interaction with Vif protein.