Distinciones para el CEFOBI en el Congreso SAIB 2018

Nuestros becarios/tesinistas fueron distinguidos en el LIV Congreso de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, realizado del 5 al 8 de noviembre de 2018 en Paraná, Entre Ríos:

 

Lic. Manuel Balparda (Mejor Exposición Oral, Sección Plantas)

PAP-SAL1 CHLOROPLAST RETROGRADE PATHWAY MODULATES IRON DEFICIENCY RESPONSE IN ALKALINE SOILS

Balparda M; Gomez-Casati DF; Pagani MA

Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI – CONICET), Universidad Nacional de Rosario

E-mail: balparda@cefobi-conicet.gov.ar
 

Iron (Fe) is an essential micronutrient for plants and is present abundantly in the Earth’s crust. However, its bioavailability in most soils is low, due to their alkaline pH that lowers the solubility of the metal. In previous communications, we have demonstrated the existence of a link between the organelle-nucleus retrograde signaling PAP-SAL1 pathway, which senses the internal Fe deficiency, and the iron uptake activity in roots. One of the objectives of this study was to characterize mutant plants in this signaling pathway with respect to their growth in alkaline soils. We measured phenotypic characteristics such as rosette area and chlorophyll content, and we observed that mutant lines presented an increment in both compared to Wild-Type Col-0 plants. Likewise, we studied genes implicated in the biosynthesis of secondary metabolites derived from phenylpropanoids, which, excreted to the rhizosphere, improve Fe availability, in two different pH conditions: 5.7 (control) and 7.5 (alkaline). The relative expressions of these genes were elevated in mutant lines compared with Wild-Type seedlings in both pH conditions. Finally, we quantified the phenolic compounds excreted to the rhizosphere. Results show an increase in these metabolites in the culture medium in mutant lines compared to Wild-Type plants. In summary, PAP-SAL1 mutants show alterations in the biosynthesis of Fe-mobilizing metabolites that improve their growth in alkaline soils. As we have mentioned previously, our results suggest that the PAP-SAL1 retrograde pathway has a connection with Fe deficiency sensing in Arabidopsis thaliana

 
 

Est. Estefanía Pavesi (Mejor Póster, Sección Biología Celular)

LIGHT EFFECT ON Acinetobacter VIRULENCE

Pavesi E12,Tuttobene M1, Ramírez MS3,Diacovich L2,Mussi A1

1 CEFOBI-CONICET. FBIOyF-UNR 2 IBR – CONICET. FBIOyF-UNR – 3Center for Applied Biotechnology Studies

E-mail: estefaniaspavesi@gmail.com
 

In our group we have found that many bacterial pathogens such as Acinetobacter baumannii sense and respond to light integrating also a temperature signal. We have extensively characterized photoregulation at moderate temperatures such as 24ºC in this microorganism, showing that light exerts a global effect on its physiology modulating aspects related to persistence in the environment as well as virulence. We have shown that many of these processes depend on the blue light using FAD (BLUF) photoreceptor BlsA, which is a global regulator able to bind and antagonize the functioning of transcriptional regulators such as Fur in a light-dependent manner.Regulation by light occurs not only in A. baumannii, but is also widely distributed within the Acinetobacter genus. Most non-baumanniispecies harbor between two and six BlsA homologs, and photoregulation occurs not only at 24 but also at 37ºC. Many of these species are environmental, while others like Acinetobacter A47 and nosocomialis are important human pathogens. A. nosocomialis harbors three BLUF photoreceptors while A47 harbors two, modulating susceptibility to antibiotics, motility, iron uptake and hemolysis in the last case. Regulation by light at 37ºC in important pathogens could affect bacterial infections in humans. This situation could be particularly relevant for these pathogens given that they produce infections in skin wounds surface-exposed and soft tissue.In this work, we evaluate the effect of light in infections by A47, A. nosocomialis and A. baumannii towards a human keratinocyte cell line in culture, HaCaT. The model resembles skin wound infections, in which the stratum corneum has lost integrity and the bacteria come in direct contact with the cells. In this context, this model reflects situations in real infections, given that these species of Acinetobacter are recognized as natural colonizers of human skin. In this work, we have optimized infections using this model, varying the multiplicity of infection (MOI), time for adhesion or internalization, as well as antibiotic treatment. Our results so far show that light exerts an effect on A. nosocomialis virulence towards HaCaT cells, becoming the bacteria more virulent when in the dark rather than under blue light. In non-baumanniispecies, some processes such as biofilm formation, iron uptake or motility are regulated by light inversely than in A. baumannii, and in this work we show that virulence is also affected. Our results also pose the possibility that light could be regarded as a tool to control infections by these microorganisms.

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