Direct in vitro regeneration of castor bean plants (Ricinus communis) using epicotyls / Regeneração direta in-vitro de plantas de mamona ( Ricinus communis ) usando epicótilos

A regeneration protocol for castor bean plant (Ricinus communis) was successfully developed using epicotyl sections obtained from in vitro seedlings. The maximum number of induced shoots (4.3 shoots/explant) and highest shoots frequency (75,56%) was obtained in WPM medium supplemented with TDZ (1 mg/L) and zeatin (0.5 mg/L), whereas the minimum number (0.8 shoots/explant) and lowest shoots frequency (37,78%) was obtained in medium containing TDZ (1 mg/L) and BAP (0.5 mg/L). The highest percentage of rooting (93.3%) was obtained in a medium containing IBA (1 mg/L). These plants were transplanted in a mesh house and achieved a high adaptability to acclimatization, reaching 77% survival. On the other hand, the maximum elongation (height) during this stage was 7.9 cm in plants supplemented with WPM nutrients, whereas it was only 4.38 cm in control plants

Foi desenvolvido com sucesso um protocolo de regeneração para a planta de Mamona (Ricinus communis) utilizando seções de epicótilos, obtidas a partir de mudas in vitro. O número máximo de brotações induzidas (4.3 brotos/explante), assim como a maior frequência de brotações (75,56%), foi obtido em meio WPM suplementado com TDZ (1 mg/L) e zeatina (0,5 mg/L). Enquanto que o número mínimo (0,8 brotos/explante), como a menor freqüência de rebentos (37,78%), foi obtido em meio contendo TDZ (1 mg/L) e BAP (0,5 mg/L). Adicionalmente, a maior percentagem de enraizamento (93,3%) foi obtida em um meio contendo IBA (1 mg/L). Depois da regeneração, as plantas foram transplantadas em casa de vegetação e conseguiram uma alta adaptabilidade e aclimatização, atingindo 77% de sobrevivência. Por outro lado, oalongamento máximo (altura) durante este estágio foi de 7,9 cm em plantas suplementadas com nutrientes de WPM, enquanto as plantas de controle presentaram apenas 4,38 cm

Reviewing Microbial Behaviors in Ecosystems Leading to a Natural Quorum Quenching Occurrence

ABSTRACT Quorum sensing is considered one of the most important discoveries in cell-to-cell communication. Although revealed in Bacteria, it has been identified as well as a mechanism present in the other two domains, Eukaryota and Archaea. This phenomenon consists mainly of an exchange and sensing of "words" produced by each cell: chemical signals known as autoinducers. The process takes places at high cell densities and confined environments, triggering the expression of specific genes that manifest in a determined phenotype. Quorum sensing has a fundamental importance in the organisms' fitness in natural ecosystems since it activates many of the traits needed by cells to survive under specific conditions, and thus a wide variety of chemical signals, which are detailed throughout the review, have evolved in response to the needs of an organism in the ecosystem it inhabits. As a counterpart, derived from the natural occurrence of quorum sensing, comes it's antagonistic process named quorum quenching. Acting in the exact opposite way, quorum quenching interferes or degrades the autoinducers confusing and stopping communication, hence affecting transcriptional regulation and expression of a specific phenotype. The main reasons for stopping this mechanism go from fading their own signals when perceiving scarce nutrients conditions, to degrading competitors' signals to take advantage in the ecosystem. Some of the most studied purposes and means known up to date to be used by cells for making quorum quenching in their ecosystems is what will be discussed along this review, offering information for future works on quorum quencher molecules bioprospection.