In vivo trans-specific gene silencing in fungal cells by in planta expression of a double-stranded RNA

<p>Abstract</p> <p>Background</p> <p>Self-complementary RNA transcripts form a double-stranded RNA (dsRNA) that triggers a sequence-specific mRNA degradation, in a process known as RNA interference (RNAi), leading to gene silencing. In vascular plants, RNAi molecules trafficking occur between cells and systemically throughout the plant. RNAi signals can spread systemically throughout a plant, even across graft junctions from transgenic to non-transgenic stocks. There is also a great interest in applying RNAi to pathogenic fungi. Specific inhibition of gene expression by RNAi has been shown to be suitable for a multitude of phytopathogenic filamentous fungi. However, double-stranded (ds)RNA/small interfering (si)RNA silencing effect has not been observed <it>in vivo</it>.</p> <p>Results</p> <p>This study demonstrates for the first time the <it>in vivo </it>interference phenomenon in the pathogenic fungus <it>Fusarium verticillioides</it>, in which expression of an individual fungal transgene was specifically abolished by inoculating mycelial cells in transgenic tobacco plants engineered to express siRNAs from a dsRNA corresponding to the particular transgene.</p> <p>Conclusion</p> <p>The results provide a powerful tool for further studies on molecular plant-microbe and symbiotic interactions. From a biotechnological perspective, silencing of fungal genes by generating siRNAs in the host provides a novel strategy for the development of broad fungi-resistance strategies in plants and other organisms.</p

Comparison of Bothropoides jararaca bites with and without envenoming treated at the Vital Brazil Hospital of the Butantan Institute, State of São Paulo, Brazil Comparação dos acidentes causados por Bothropoides jararaca com e sem envenenamento atendidos no Hospital Vital Brazil do Instituto Butantan, Estado de São Paulo

INTRODUCTION: This study analyses the cases of all bites (including dry bites) caused by Bothropoides jararaca attended at the Vital Brazil Hospital of the Butantan Institute, State of São Paulo, Brazil. METHODS: A retrospective study was conducted of patients bitten by Bothropoides jararaca (n=792) from January 1990 to December 2004. The characteristics of the snake specimen, data related to the accident and clinical manifestations on admission were obtained from patient medical records. RESULTS: The majority of the cases in this study were caused by female and juvenile snakes. No stomach contents were found in 93.4% of the snake specimens after dissection. No statistical difference was observed between the occurrence of dry bites and the maturity or sex of the snake. The median SVL of snakes in mild and moderate cases was 40.5cm and in severe cases, SVL increased to 99cm. Necrosis was more common in the digits of the feet and hands (4.8%) compared to the other body regions (1.8%). A significant difference was verified between severity and a time interval greater than six hours from the bite to hospital admission. A significant association was verified between gingival bleeding and abnormal blood coagulability. In accidents caused by adult snakes, necrosis was more frequent (7.2%) compared to accidents caused by juvenile snakes (1%). CONCLUSIONS: In this work, the association between certain epidemiological data and the evolution of biological parameters in the clinical course of Bothrops sensu latu accidents were highlighted, contributing to the improvement of snake bite assistance.<br>INTRODUÇÃO: Neste estudo, analisou-se todos os casos de picadas (incluindo picadas secas) causadas por Bothropoides jararaca atendidos no Hospital Vital Brazil do Instituto Butantan, São Paulo, Brasil. MÉTODOS: Estudo retrospectivo em que foram incluídos pacientes atendidos no Hospital Vital Brazil do Instituto Butantan, picados por serpentes da espécie Bothropoides jararaca (nº=792) entre 1990 a 2004. Os dados foram obtidos através de prontuários médicos. RESULTADOS: No presente estudo, a maioria dos acidentes foi causada por serpentes fêmeas e filhotes. Não havia presença de conteúdo estomacal em 93,4% das serpentes dissecadas. Não houve diferença estatística entre a ocorrência de picada seca e o sexo da serpente. O comprimento rostro cloacal das serpentes nos casos leves e moderados foram 40,5cm e nos casos severos 99cm. Necrose foi mais comum nos dedos dos pés e das mãos (4,8%) em comparação com outras regiões do corpo (1,8%). Houve diferença estatística entre a gravidade e o intervalo de tempo entre a picada e a admissão hospitalar superior a seis horas. Encontramos uma associação significativa entre gengivorragia e incoagulabilidade sanguínea. Nos acidentes causados por serpentes adultas, a necrose foi mais frequente (7,2%) quando comparado aos acidentes causados por serpentes filhotes (1%). CONCLUSÕES: Neste estudo, destaca-se a associação entre os dados epidemiológicos e biológicos em relação à evolução do quadro clínico nos acidentes botrópicos, contribuindo para a melhoria da assistência nos acidentes ofídicos