Instituto Superior Of Investigaciones Biologicas Insibio

Instituto Superior Of Investigaciones Biologicas Insibio

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Romero C.M.,CONICET | Pera L.M.,CONICET | Loto F.,CONICET | Vallejos C.,Instituto Superior Of Investigaciones Biologicas Insibio | And 2 more authors.
Biocatalysis and Agricultural Biotechnology | Year: 2012

An organic solvent-tolerant lipase from olive oil-induced Aspergillus niger MYA 135 supernatant was purified using two methods: electroelution and ion-exchange chromatography. With electroelution purification was 8.4-fold and recovery 47% and with ion-exchange 16.6-fold and 53.4%, respectively. The purified enzyme showed a prominent single band with SDS-PAGE and was a monomeric protein of 68kDa. The isoelectric point (pI) of the lipase was 5.1 and optimum pH and temperature for activity were 7.0 and 37°C, respectively. The lipase showed affinity for esters with long acyl chains, with a K m of 0.99mM for C18. Substrate specificity of the immobilized lipase was highest for C18 among the various α- and Β-naphthyl esters assayed. Substrate specificity agreed with kinetics parameters of long-chain fatty acids (C18). Transesterification activity of the A. niger MYA 135 lipase indicates that it could be a potential biocatalyst for biodiesel production. © 2011 Elsevier Ltd.

Barrera D.,Instituto Superior Of Investigaciones Biologicas Insibio | Llanos R.J.,Instituto Superior Of Investigaciones Biologicas Insibio | Miceli D.C.,Instituto Superior Of Investigaciones Biologicas Insibio
Zygote | Year: 2012

Summary The acquisition of egg fertilizability in Bufo arenarum takes place during the oviductal transit and during this process the extracellular coelomic envelope (CE) of the eggs is converted into the vitelline envelope (VE). It has been stated that one of the necessary events leading to a fertilizable state is the proteolytic cleavage of CE glycoproteins in the oviductal pars recta by oviductin, a serine protease. Consequently, there is a marked increase in the relative quantity of glycoproteins with 39 (gp39) and 42 kDa (gp42) in the VE. In the present study, sperm-VE binding assays using heat-solubilized biotin-conjugated VE glycoproteins revealed that both gp39 and gp42 have sperm binding capacity. According to this result, our study was focused on gp39, a glycoprotein that we have previously reported as a homologue of mammalian ZPC. For this purpose, rabbit polyclonal antibodies against gp39 were generated at our laboratory. The specificity of the antibodies was confirmed with western blot of VE glycoproteins separated on SDS-PAGE. Immunohistochemical and immunoelectron studies showed gp39 distributed throughout the width of the VE. In addition, immunofluorescence assays probed that gp39 bound to the sperm head. Finally, as an approach to elucidate the possible involvement of gp39 in fertilization, inhibition assays showed that pretreatment of eggs with antibodies against gp39 generated a significant decrease in the fertilization rate. Therefore, our findings suggest that gp39, which is modified by oviductal action, participates as a VE glycoprotein ligand for sperm in Bufo arenarum fertilization. © 2011 Cambridge University Press.

Mamani A.,Instituto Superior Of Investigaciones Biologicas Insibio | Filippone M.P.,Seccion Biotecnologia | Grellet C.,Instituto Superior Of Investigaciones Biologicas Insibio | Welin B.,Seccion Biotecnologia | And 2 more authors.
Molecular Plant-Microbe Interactions | Year: 2012

In an incompatible interaction between Colletotrichum fragariae and strawberry plants, the accumulation of phenolic compounds in plant leaves was observed. A particularly abundant penta-esterified ellagitannin that accumulated in response to pathogen attack was identified as 1-0-galloyl-2,3;4,6-bis- hexahydroxydiphenoyl-β-D-glucopyranose (HeT) by mass spectroscopy and nuclear magnetic resonance. Foliar application of purified HeT prior to inoculation with a virulent pathogen was shown to increase resistance toward C. acutatum in strawberry plants and to Xanthomonas citri subsp. citri in lemon plants. The induced resistance in strawberry was associated with a rapid oxidative burst, callose deposition, a transient increase of salicylic acid in phloem, and induction of gene expression responsive to salicylic acid. Results obtained suggested that HeT could be a common plant defense response molecule capable of inducing pathogen resistance in different plant species. © 2012 The American Phytopathological Society.

There is great interest in consuming foods that can provide the nutrients for a good nutrition and other health beneficial compounds. The aim of this work was to determine the chemical composition of native foods of the Andean region and to quantify some functional components. Proximal composition, vitamin C, total phenolic compounds, antiradical activity (DPPH) in peel and pulp, dietary fiber soluble and insoluble, fructooligosaccharides (FOS), total and resistant starch (in tubers and raw roots, boiled and boiled and stored) of 6 varieties of Oca (Oxalis tuberosa), 4 clones of manioc (Manihot esculenta Crantz) and yacon (Smallanthus sonchifolius were determined. The results showed greater amount of bioactive compounds and antiradical activity in the skin of these products. The highest content was found in the oca peel. In all cases, the content of insoluble fiber was greater than the soluble. The manioc had higher total starch than Andean roots and tubers. The boiling process decreased the resistant starch content of ocas and maniocs, but when these are stored for 48 h at 5 ° C, the resistant starch content increased. The FOS content of the ocas was similar for all varieties (7%). The main component of yacon carbohydrates were FOS (8,89%). The maniocs did not contain FOS. It can be concluded that the roots and tubers studied, in addition to provide nutrients, contain functional compounds that confer additional helpful value for preventing no communicable diseases. © 2014, Archivos Latinoamericanos Nutricion. All rights reserved.

Martinez-Gil M.,CSIC - Experimental Station of El Zaidín | Quesada J.M.,CSIC - Experimental Station of El Zaidín | Ramos-Gonzalez M.I.,CSIC - Experimental Station of El Zaidín | Soriano M.I.,CSIC - Experimental Station of El Zaidín | And 3 more authors.
Research in Microbiology | Year: 2013

The extracellular matrix of bacterial biofilms has at least two key functions: to serve as a structural scaffold for the multicellular community, and to play a protective role against external stress. In this work, we report a compensatory effect whereby Pseudomonas putida reacts to the lack of either of the two main surface proteins involved in biofilm formation, LapA and LapF, by increasing expression and production of a species-specific EPS. Elevated levels of the second messenger molecule cyclic di-GMP alter the balance of extracellular matrix components, and the phenotypes of lapA and lapF mutants under these conditions are indicative of direct interactions taking place between large secreted proteins and exopolysaccharides. Our data suggest the existence of a mechanism by which bacteria would sense alterations in the composition of the extracellular matrix, leading to changes in expression of the different elements. © 2013 Institut Pasteur.

Ontivero M.,Seccion Biotecnologia | Zamora G.M.,Instituto Superior Of Investigaciones Biologicas Insibio | Salazar S.,Instituto Nacional de Tecnologia Agropecuaria | Salazar S.,National University of Tucuman | And 2 more authors.
Genome | Year: 2011

Actin depolymerizing factors (ADFs) have been recently implicated in plant defense against pathogenic fungi, associated with the cytoskeletal rearrangements that contribute to establish an effective barrier against fungal ingress. In this work, we identified a DNA fragment corresponding to a part of a gene predicted to encode an ADF-like protein in genotypes of Fragaria ananassa resistant to the fungus Colletotrichum acutatum. Bulked segregant analysis combined with AFLP was used to identify polymorphisms linked to resistance in hybrids derived from the cross between the resistant cultivar 'Sweet Charlie' and the susceptible cultivar 'Pájaro'. The sequence of one out of three polymorphic bands detected showed significant BLASTX hits to ADF proteins from other plants. Two possible exons were identified and bioinformatic analysis revealed the presence of the ADF homology domain with two actin-binding sites, an N-terminal phosphorylation site, and a nuclear localization signal. In addition to its possible application in strawberry breeding programs, these finding may contribute to investigate the role of ADFs in plant resistance against fungi. © 2011 Published by NRC Research Press.

Salazar S.M.,Instituto Superior Of Investigaciones Biologicas Insibio | Grellet C.F.,Instituto Superior Of Investigaciones Biologicas Insibio | Chalfoun N.R.,Instituto Superior Of Investigaciones Biologicas Insibio | Castagnaro A.P.,Instituto Superior Of Investigaciones Biologicas Insibio | Diaz Ricci J.C.,Instituto Superior Of Investigaciones Biologicas Insibio
European Journal of Plant Pathology | Year: 2013

Strawberry plants exposed to an avirulent isolate of Colletotrichum fragariae acquired strong resistance against a virulent strain of C. acutatum. Biochemical, morphological and molecular markers indicated that the strong defence response was associated with an oxidative burst and a transient accumulation of salicylic acid (SA). A maximum accumulation of H2O2 and O2 - was observed 8 h after inoculation (hai), callose was detected 48 hai, and a peak of SA was observed 48 hai. Biochemical and phytopathogenic analyses carried out in non-treated tissues revealed that the defence response was systemic and remained fully active 60 days after the first inoculation. Experiments also showed that the resistance acquired by mother plants after the inoculation with the avirulent isolate could be passed to daughter plants through runners. Further characterization of the induced systemic resistance showed that the resistance was not only effective against a virulent strain of C. acutatum but also against Botrytis cinerea. © 2012 KNPV.

Racedo J.,Instituto Superior Of Investigaciones Biologicas Insibio | Salazar S.M.,Instituto Superior Of Investigaciones Biologicas Insibio | Castagnaro A.P.,CONICET | Diaz Ricci J.C.,Instituto Superior Of Investigaciones Biologicas Insibio
European Journal of Plant Pathology | Year: 2013

We report Acremonium strictum as the causal agent of a new disease in strawberry plants (Fragaria x ananassa Duch.) in the Northwest of Argentina. Both the structure of conidiophores and the sequence spanning the internal transcribed spacers 1 and 2 (ITS1 and ITS2) of the nuclear ribosomal DNA (rDNA) allowed confirming the affiliation of the isolate, corresponding to A. strictum. An analysis of symptoms and lesions caused by the strain of A. strictum in susceptible cultivars showed that the typical symptoms are as follows: in an early stage, small necrotic light-brown spots in leaves and petioles increase in number and size as the disease progresses; in a more advanced stage, dark necrotic areas expand over petioles and leaves causing strangulation of petioles and the plant wilt. Crown rot was not observed even at a very advanced stage of the disease. © 2013 KNPV.

Corbalan N.S.,Instituto Superior Of Investigaciones Biologicas Insibio | Adler C.,Instituto Superior Of Investigaciones Biologicas Insibio | De Cristobal R.E.,Instituto Superior Of Investigaciones Biologicas Insibio | Pomares M.F.,Instituto Superior Of Investigaciones Biologicas Insibio | And 2 more authors.
FEMS Microbiology Letters | Year: 2010

The SbmA protein is involved in the transport of MccB17-, MccJ25-, bleomycin- and proline-rich peptides into the Escherichia coli cytoplasm. sbmA gene homologues were found in a variety of bacteria. However, the physiological role of this protein still remains unknown. Previously, we found that a combination of sbmA and tolC mutations in Tn10-carrying E. coli K-12 strains results in hypersusceptibility to tetracycline. In this work, we studied sbmA expression in a tolC mutant background and observed an increased expression throughout growth. We ruled out the global transcriptional regulator RpoS and the small RNA micF as intermediates in this regulation. The tolC mutation induced the expression of other well-characterized strong σE- dependent promoters in E. coli. We observed that the increase in σE activity led to a greater sbmA expression, conversely eliminating σE prevented expression of sbmA. We also observed that the sbmA upregulation in a tolC mutant context was abolished in an rpoE-null strain. These results suggest a σE-dependent positive regulation on sbmA by the tolC mutation. We hypothesize that this mechanism might be part of a compensatory cell envelope stress response. © 2010 Federation of European Microbiological Societies.

Chalfoun N.R.,Instituto Superior Of Investigaciones Biologicas Insibio | Castagnaro A.P.,Instituto Superior Of Investigaciones Biologicas Insibio | Diaz Ricci J.C.,Instituto Superior Of Investigaciones Biologicas Insibio
Biological Control | Year: 2011

In a previous report, it was described that strawberry plants pre-treated with an avirulent isolate of Colletotrichum fragariae (M23) acquired resistance to a virulent isolate of Colletotrichum acutatum (M11) causing anthracnose. In this report we present evidence that the eliciting activity can be found not only in conidial extracts but in culture supernatants of the avirulent pathogen as well. Plants of the cv. Pájaro treated with the culture filtrate (CF) derived from M23, 3. days prior to the inoculation with M11 showed significantly reduced disease severity as compared to control plants and the disease was completely suppressed when plants were pre-treated 7. days before the challenge inoculation with M11. The same effect was achieved when a single leaf was sprayed with CF, suggesting that the resistance acquired is systemic. Control treatments showed that none of the active extracts inhibited the growth of the virulent pathogen, indicating that the protection effect was due to the induction of a defense response. The latter was confirmed by the accumulation of reactive oxygen species (e.g. hydrogen peroxide, superoxide anion) and the deposition of lignin and callose, usually associated to plant defense, after the CF treatment. Experiments carried out with other strawberry cultivars treated with CF showed that also protected them against different virulent isolates, suggesting that the response observed is cultivar-nonspecific. These outcomes indicate that the protection against anthracnose in strawberry involves a phenomenon of induced resistance (IR) by action of defense-eliciting molecules produced by M23. © 2011 Elsevier Inc.

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