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Papers by Analia Principe

La innovación constituye un aspecto muy valorado en la vida humana. La innovación pedagógica pare... more La innovación constituye un aspecto muy valorado en la vida humana. La innovación pedagógica pareciera ser inherente a toda educación: enseñar y aprender suponen necesariamente la novedad. Si se repiten cosas conocidas por el estudiante, no hay enseñanza y, si este no se enfrenta con algo nuevo que lomovilice cognitivamente, tampoco hay aprendizaje, al menos significativo, profundo y de relevancia, de esos que son indispensables construir en una buena formación. Por ese motivo, diseñar, implementar y evaluar innovaciones pedagógicas son tareas muy complejas que requieren de conocimientos, tecnologíasy condiciones institucionales que promuevan el trabajo colaborativo e interdisciplinario desde paradigmas críticos fundamentados en políticas académicas que asuman a la relación teórico-práctica, a la inclusión ya la calidad educativa como sus pilares básicos.Este es el marco de los trabajos que se incluyen en esta publicación. Se trata de experiencias pedagógicas diseñadas e implementadas en las cinco facultades de la Universidad Nacional de Río Cuarto (UNRC) que se convirtieron en objeto de reflexión compartida de los equipos docentes que las impulsaron y quemuestran interés por hacerlas públicas; de esta manera, trascienden la microfísica del espacio del aula en donde cobraron vida. Es necesario darlas a conocer, por sus alcances y limitaciones, por las reflexiones que suscitan, por su potencial innovador y por la generosidad de sus autores para exponerlas a la crítica y al debate, con la expectativa de que los aportes recibidos vuelvan para enriquecer las experiencias y saberes en un sentido superador.En consonancia con su condición pública, en la UNRC la publicación de innovaciones constituye una práctica frecuente. Hay una disposición institucional para dar a conocer de manera abierta y generalizadalas diversas producciones tanto en el plano académico de la formación como en el ámbito de la investigación y la vinculación con los diversos contextos socioculturales y comunitarios. Se manifiesta permanentemente el interés por compartir, por hacer conocer, por visibilizar al trabajo, sus procesos y resultados; hacerlos públicos no solo para ser conocidos, sino también para que aporten al pensamiento y a la mejora y recepten las contribuciones del contexto.En este sentido, se asume el lema del escudo institucional que, desde su fundación, signa con fuerza a la cultura de la universidad. Apostar a los sujetos, a la comunidad, al trabajo y a la ciencia para construirconocimientos relevantes en una transformación encaminada hacia una sociedad más igualitaria y humana constituye el significado del símbolo que identifica a la institución. Por ello, creer, crear y crecer se imbrican con la innovación.Fil: Principe, Analia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibañez, Fernando. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; ArgentinaFil: Tonelli, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Anzuay, María Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bianucci, Eliana Carolina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernandez, Maricruz. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ludueña, Liliana Mercedes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Flores Cáceres, María Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Furlan, Ana Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo…

Journal of Biotechnology, Feb 1, 2018

Highlights  Forty different bacterial genera were found as seed-endophytes in alfalfa.  Seed en... more Highlights  Forty different bacterial genera were found as seed-endophytes in alfalfa.  Seed endophytes presented in-vitro activities related to plant-growth promotion.  Many isolates of the identified genera were found as alfalfa-plant endophytes  Alfalfa seeds are natural carriers of (likely selected) bacterial inocula to plants.

Archives of Microbiology, Aug 2, 2014

Journal of Biotechnology, Aug 1, 2017

Highlights  The effect of phage tail-like bacteriocin from P. fluorescens is analysed through AF... more Highlights  The effect of phage tail-like bacteriocin from P. fluorescens is analysed through AFM.  Tailocins inhibit the growth of the phytopathogenic strain Xanthomonas axonopodis.  Tailocins adhere to the cell wall of X. axonopodis.  Tailocins damage the cellular envelope of phytopathogenic bacteria.  Tailocins could be used in the future as biocontrol agents.

Research in Microbiology, Apr 1, 2016

Pseudomonas fluorescens SF39a is a plant-growth-promoting bacterium isolated from wheat rhizosphe... more Pseudomonas fluorescens SF39a is a plant-growth-promoting bacterium isolated from wheat rhizosphere. In this report, we demonstrate that this native strain secretes bacteriocins that inhibit growth of phytopathogenic strains of the genera Pseudomonas and Xanthomonas. An S-type pyocin gene was detected in the genome of strain SF39a and named pys. A non-polar pys::Km mutant was constructed. The bacteriocin production was impaired in this mutant. To identify genes involved in bacteriocin regulation, random transposon mutagenesis was carried out. A miniTn5Km1 mutant, called P. fluorescens SF39a-451, showed strongly reduced bacteriocin production. This phenotype was caused by inactivation of the ptsP gene which encodes a phosphoenolpyruvate phosphotransferase (EI Ntr) of the nitrogen-related phosphotransferase system (PTS Ntr). In addition, this mutant showed a decrease in biofilm formation and protease production, and an increase in surface motility and pyoverdine production compared with the wild-type strain. Moreover, we investigated the ability of strain SF39a-451 to colonize the wheat rhizosphere under greenhouse conditions. Interestingly, the mutant was less competitive than the wild-type strain in the rhizosphere. To our knowledge, this study provides the first evidence of both the relevance of the ptsP gene in bacteriocin production and functional characterization of a pyocin S in P. fluorescens.

Fems Microbiology Letters, Jun 1, 2009

The plant growth-promoting rhizobacterium, Ochrobactrum sp. 11a displays a high intrinsic salinit... more The plant growth-promoting rhizobacterium, Ochrobactrum sp. 11a displays a high intrinsic salinity tolerance and has been used in this work to study the molecular basis of bacterial responses to high concentrations of NaCl. A collection of Ochrobactrum sp. 11a mutants was generated by Tn5-B21 mutagenesis and screened for sensitivity to salinity. One clone, designated PBP and unable to grow on glutamate mannitol salt agar medium supplemented with 300 mM NaCl was selected and further characterized. The PBP mutant carries a single transposon insertion in a gene showing a high degree of identity to the serine-type D-alanyl-Dalanine carboxypeptidase gene of Ochrobactrum anthropi. Interestingly, the expression of this gene was shown to be upregulated by salt in the PBP mutant. Moreover, evidence is presented for the requirement of the gene product for adaptation to high-salt conditions as well as to overcome the toxicity of LiCl, KCl, sucrose, polyethylene glycol (PEG), AlCl 3 , CuSO 4 , and ZnSO 4. In addition to the altered tolerance to both ionic and osmotic stresses, the PBP mutant exhibited changes in colony and cell morphology, exopolysaccharide production, and an increased sensitivity to detergents.

Microbiological Research, Jul 1, 2018

The development of alternatives for the use of chemical pesticides for plant disease control is t... more The development of alternatives for the use of chemical pesticides for plant disease control is the present-day and ongoing challenge for achieving sustainable agriculture. Pseudomonas fluorescens SF4c, native strain from wheat, produces tailocins (phage-tail-like bacteriocins) with antimicrobial activity against several phytopathogenic strains. We thus investigated the efficacy of foliar application of these bacteriocins to control the bacterial-spot disease in tomato caused by Xanthomonas vesicatoria Xcv Bv5-4a. The disease severity and incidence index were reduced by 44 and 36%, respectively; while the number of viable cells of X. vesicatoria Xcv Bv5-4a decreased after bacteriocin treatment. Furthermore, bacteriocin was effective in reducing bacterial-spot-disease symptoms on tomato fruits even when applied 12 h after infection. Tailocin activity was not affected by abiotic influences such as adjuvant, light and temperature and, biotic factors such as apoplastic-fluids. In contrast, no antibacterial activity of these tailocins was observed when the bacteriocin was exposed to extremely dry conditions. Finally, that no cytotoxic effects on mammalian cells were observed with this representative tailocins is highly significant and demonstrates the safety of such compounds in humans. All these findings indicate that the SF4c tailocins represent an attractive alternative to copper-containing bactericides for use in the control of bacterial spot.

Current Microbiology, Aug 13, 2007

A bacterial collection of approximately one thousand native strains, isolated from saline soils o... more A bacterial collection of approximately one thousand native strains, isolated from saline soils of Cordoba province (Argentina), was established. From this collection, a screening to identify those strains showing plant growth promotion and biocontrol activities, as well as salt tolerance, was performed. Eight native strains tolerant to 1 M: NaCl and displaying plant growth promotion and/or biocontrol features were selected for further characterization. Strains MEP(2 )18, MRP(2 )26, MEP(2 )11a, MEP(3 )1, and MEP(3 )3b significantly increased the growth of maize seedlings under normal and saline conditions, whereas isolates ARP(2 )3, AEP(1 )5, and ARP(2 )6 were able to increase the root dry weight of agropyre under saline conditions. On the other hand, strains MEP(2 )18 and ARP(2 )3 showed antagonistic activity against phytopathogenic fungi belonging to Sclerotinia and Fusarium genus. Antifungal activity was found in cell-free supernatants, and it was heat and protease resistant. Strains MEP(2)18 and ARP(2)3 were identified as Bacillus sp. and strains MEP(2)11a and MEP(3)3b as Ochrobactrum sp. according to the sequence analysis of 16S rRNA gene.

Current Microbiology, May 1, 2014

Genome Announcements, Apr 30, 2015

Pseudomonas fluorescens strains Wayne1R and Wood1R have proven capacities to improve plant health... more Pseudomonas fluorescens strains Wayne1R and Wood1R have proven capacities to improve plant health. Here we report the draft genome sequences and automatic annotations of both strains. Genome comparisons reveal similarities with P. fluorescens strain Pf-5, reveal the novelty of Wood1R, and indicate some genes that may be related to biocontrol.

Soil biology, 2013

Plant growth-promoting bacteria (PGPBs) are capable of colonizing plants and influencing their gr... more Plant growth-promoting bacteria (PGPBs) are capable of colonizing plants and influencing their growth by direct or indirect mechanisms. The direct mode of action occurs when metabolites or compounds synthesized by microorganisms are provided to the plant—for example, phytohormones—or when the bacteria facilitate the plant’s uptake of certain nutrients from the environment. In the indirect form of promotion, bacteria protect the plant against phytopathogenic organisms through the induction of systemic resistance and/or by the synthesis of antimicrobial compounds. The use of beneficial microorganisms as biopesticides offers a promising alternative to the use of chemical pesticides and an environmentally friendly strategy for agriculture. The PGPBs most studied and exploited as biocontrol agents are the species of Bacillus and fluorescent Pseudomonas. These strains produce a wide variety of metabolites involved in the biologic control of phytopathogenic fungi—for example, extracellular enzymes, siderophores, antibiotics, hydrogen cyanide, and volatile organic compounds, among others. Antibiosis is one mechanism of biologic control that is well characterized in Bacillus and Pseudomonas strains both genetically and biochemically. Among antibiotics identified in these two genera include the cyclic lipopeptides such surfactin, iturin, and fengycin in the bacilli and phenazines, 2,4-diacetylphloroglucinol, pyoluteorin, and pyrrolnitrin in the pseudomonads.

Fems Microbiology Letters, Dec 8, 2008

Bacteria of the genus Azospirillum are free-living nitrogen-fixing, rhizobacteria that are found ... more Bacteria of the genus Azospirillum are free-living nitrogen-fixing, rhizobacteria that are found in close association with plant roots, where they exert beneficial effects on plant growth and yield in many crops of agronomic importance. Unlike other bacteria, little is known about the genetics and biochemistry of exopolysac charides in Azospirillum brasilense. In an attempt to characterize genes associated with exopolysaccharides production, we generated an A. brasilense Cd Tn5 mutant that showed exopolysaccharides overproduction, decreased tolerance to saline conditions, altered cell morphology, and increased sensitivity to detergents. Genetic characterization showed that the Tn5 was inserted within a ddlB gene encoding for a D-alanine-D-alanine ligase, and located upstream of the ftsQAZ gene cluster responsible for cell division in different bacteria. Heterologous complementation of the ddlB Tn5 mutant restored the exopolysaccharides production to wild-type levels and the ability to grow in the presence of detergents, but not the morphology and growth characteristics of the wild-type bacteria, suggesting a polar effect of Tn5 on thefts genes. This result and the construction of a nonpolar ddlB mutant provide solid evidence of the presence of transcriptional coupling between a gene associated with peptidoglycan biosynthesis and the fts genes required to control cell division.

Journal of Biotechnology, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Systematic and Applied Microbiology, Jul 1, 2012

Pseudomonas strains producing antimicrobial secondary metabolites play an important role in the b... more Pseudomonas strains producing antimicrobial secondary metabolites play an important role in the biocontrol of phytopathogenic fungi. In this study, native Pseudomonas spp. isolates were obtained from the rhizosphere, endorhizosphere and bulk soil of maize fields in Córdoba (Argentina) during both the vegetative and reproductive stages of plant growth. However, the diversity based on repetitive-element PCR (rep-PCR) and amplified ribosomal DNA restriction analysis (ARDRA) fingerprinting was not associated with the stage of plant growth. Moreover, the antagonistic activity of the native isolates against phytopathogenic fungi was evaluated in vitro. Several strains inhibited members of the genera Fusarium, Sclerotinia or Sclerotium and this antagonism was related to their ability to produce secondary metabolites. A phylogenetic analysis based on rpoB or 16S rRNA gene sequences confirmed that the isolates DGR22, MGR4 and MGR39 with high biocontrol potential belonged to the genus Pseudomonas. Some native strains of Pseudomonas were also able to synthesise indole acetic acid and to solubilise phosphate, thus possessing potential plant growth-promoting (PGPR) traits, in addition to their antifungal activity. It was possible to establish a relationship between PGPR or biocontrol activity and the phylogeny of the strains. The study allowed the creation of a local collection of indigenous Pseudomonas which could be applied in agriculture to minimise the utilisation of chemical pesticides and fertilisers.

Journal of Applied Microbiology, 2011

This work was conducted to identify the antifungal compounds produced by two previously isolated ... more This work was conducted to identify the antifungal compounds produced by two previously isolated Bacillus sp. strains: ARP(2) 3 and MEP(2) 18. Both strains were subjected to further analysis to determine their taxonomic position and to identify the compounds responsible for their antifungal activity as well as to evaluate the efficiency of these strains to control sclerotinia stem rot in soybean. The antifungal compounds were isolated by acid precipitation of cell-free supernatants, purified by RP-HPLC and then tested for antagonistic activity against Sclerotinia sclerotiorum. Mass spectra from RP-HPLC eluted fractions showed the presence of surfactin C(15) , fengycins A (C(16) -C(17)) and B (C(16)) isoforms in supernatants from strain ARP(2) 3 cultures, whereas the major lipopeptide produced by strain MEP(2) 18 was iturin A C(15) . Alterations in mycelial morphology and sclerotial germination were observed in the presence of lipopeptides-containing supernatants from Bacillus strains cultures. Foliar application of Bacillus amyloliquefaciens strains on soybean plants prior to S. sclerotiorum infection resulted in significant protection against sclerotinia stem rot compared with noninoculated plants or plants inoculated with a nonlipopeptide-producing B. subtilis strain. Both strains, renamed as B. amyloliquefaciens ARP(2) 3 and MEP(2) 18, were able to produce antifungal compounds belonging to the cyclic lipopeptide family. Our data suggest that the foliar application of lipopeptide-producing B. amyloliquefaciens strains could be a promising strategy for the management of sclerotinia stem rot in soybean. Sclerotinia stem rot was ranked as one of the most severe soybean disease in Argentina and worldwide. The results of this study showed the potential of B. amyloliquefaciens strains ARP(2) 3 and MEP(2) 18 to control plant diseases caused by S. sclerotiorum.

Creer, crear y crecer con experiencias pedagógicas innovadoras, 2019

Microbiological Research, 2018

Current Microbiology, 2007

Journal of Biotechnology, 2019

Journal of biotechnology, Jan 29, 2017

A growing body of evidence has reinforced the central role of microbiomes in the life of sound mu... more A growing body of evidence has reinforced the central role of microbiomes in the life of sound multicellular eukaryotes, thus more properly described as true holobionts. Though soil was considered a main source of plant microbiomes, seeds have been shown to be endophytically colonized by microorganisms thus representing natural carriers of a selected microbial inoculum to the young seedlings. In this work we have investigated the type of culturable endophytic bacteria that are carried within surface-sterilized alfalfa seeds. MALDI-TOF analysis revealed the presence of bacteria that belonged to 40 separate genera, distributed within four taxa (Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes). Nonsymbiotic members of the Rhizobiaceae family were also found. The evaluation of nine different in-vitro biochemical activities demonstrated isolates with complex combinations of traits that, upon a Principal-Component-Analysis, could be classified into four phenotypic groups. Th...