RESUMO
Wheat is the most widely grown cereal grain, occupying a significant portion of the total cultivated land. As drought is the major environmental stressor affecting crop production, yield maintenance under water deficit conditions appears as a highly desirable phenotype for crop improvement. The HaHB4 (Helianthus annuus homeobox 4) gene from sunflower encodes for a transcription factor involved in tolerance to environmental stress. The introduction of HaHB4 in wheat led to the development of event IND-ØØ412-7 (HB4® wheat), which displayed higher yield in production environments of low productivity potential. Compositional analysis of IND-ØØ412-7 wheat, including 41 nutrients and 2 anti-nutrients for grain and 10 nutrients in forage, was performed. Results of these studies indicated that IND-ØØ412-7 is compositionally equivalent to non-transgenic wheat.
Assuntos
Aminobutiratos/farmacologia , Lipídeos/análise , Metaboloma/efeitos dos fármacos , Plantas Geneticamente Modificadas/metabolismo , Triticum/metabolismo , Herbicidas/farmacologia , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Triticum/efeitos dos fármacos , Triticum/genéticaRESUMO
Serratia marcescens is an opportunistic human pathogen that represents a growing problem for public health, particularly in hospitalized or immunocompromised patients. However, little is known about factors and mechanisms that contribute to S. marcescens pathogenesis within its host. In this work, we explore the invasion process of this opportunistic pathogen to epithelial cells. We demonstrate that once internalized, Serratia is able not only to persist but also to multiply inside a large membrane-bound compartment. This structure displays autophagic-like features, acquiring LC3 and Rab7, markers described to be recruited throughout the progression of antibacterial autophagy. The majority of the autophagic-like vacuoles in which Serratia resides and proliferates are non-acidic and have no degradative properties, indicating that the bacteria are capable to either delay or prevent fusion with lysosomal compartments, altering the expected progression of autophagosome maturation. In addition, our results demonstrate that Serratia triggers a non-canonical autophagic process before internalization. These findings reveal that S. marcescens is able to manipulate the autophagic traffic, generating a suitable niche for survival and proliferation inside the host cell.
Assuntos
Autofagia , Serratia marcescens/fisiologia , Vacúolos/microbiologia , Cloreto de Amônio/farmacologia , Androstadienos/farmacologia , Animais , Células CHO , Linhagem Celular , Cricetinae , Células Epiteliais/microbiologia , Técnica Indireta de Fluorescência para Anticorpo , Gentamicinas/farmacologia , Humanos , Macrolídeos/farmacologia , Microscopia Confocal , Serratia marcescens/efeitos dos fármacos , WortmaninaRESUMO
Serratia marcescens strains are ubiquitous bacteria isolated from environmental niches, such as soil, water, and air, and also constitute emergent nosocomial opportunistic pathogens. Among the numerous extracellular factors that S. marcescens is able to produce, the PhlA phospholipase is the only described exoprotein secreted by the flagellar apparatus while simultaneously being a member of the flagellar regulon. To gain insight into the regulatory mechanism that couples PhlA and flagellar expression, we conducted a generalized insertional mutagenesis and screened for PhlA-deficient strains. We found that three independent mutations in the wec cluster, which impaired the assembly of enterobacterial common antigen (ECA), provoked the inhibition of PhlA expression. Swimming and swarming assays showed that in these strains, motility was severely affected. Microscopic examination and flagellin immunodetection demonstrated that a strong defect in flagellum expression was responsible for the reduced motility in the wec mutant strains. Furthermore, we determined that in the ECA-defective strains, the transcriptional cascade that controls flagellar assembly was turned off due to the down-regulation of flhDC expression. These findings provide a new perspective on the physiological role of the ECA, providing evidence that in S. marcescens, its biosynthesis conditions the expression of the flagellar regulon.