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La educación virtual es un fenómeno que ha tomado auge en los últimos tiempos, por lo tanto, hacer un seguimiento de su gestión resulta primordial. El objetivo de este trabajo es ofrecer una revisión de la literatura especializada en torno a los aportes que se han levantado en la temática de la gestión de la educación virtual (GEV). El abordaje metodológico se hizo a partir de la revisión de las bases de datos Wos, Scopus, Scielo, Redalyc y Latindex. Como resultado de la revisión se identificaron un total de 33 trabajos que abordan la temática. Los criterios utilizados fueron el perfil de los autores y las colaboraciones, el alcance teórico, la concepción sobre gestión de la educación virtual, los procesos asociados a la gestión, las temáticas asociadas a las colaboraciones y, las revistas donde se está difundiendo la producción existente. Los resultados revelan escasez de estudios teóricos que discutan la gestión de la educación virtual, con lo cual se abre la posibilidad para desarrollar un nicho de investigación que más que una nueva tendencia, constituye una necesidad para adecuarse a las exigencias actuales.

a obesidad es un problema de salud pública, causado por los malos hábitos alimenticios, es un factor que puede complicar el manejo de los pacientes que presentan problemas respiratorios, en especial si requieren apoyo de ventilación mecánica invasiva, este problema se evidencia especialmente en los últimos tiempos en que se han incrementado el número de pacientes por la pandemia. Objetivo: Determinar la influencia de la obesidad en la evaluación de mortalidad en pacientes sometidos a ventilación mecánica invasiva. Material y Método: Se realizó un estudio en los pacientes del área de terapia intensiva del Hospital Luis Vernaza ingresados en el periodo desde marzo 2020 hasta marzo 2021 entre las edades de 16 y 90 años. Se utilizó las historias clínicas digitalizadas del programa SERVINTER CLINICAL SUITE (HC MEDICA – 2.6) – (Evolución Médica – 2.6.2 (chievomed) Conclusión: Los resultados reflejaron que la mayoría de los pacientes fueron personas adultas mayores y del género masculino así también Una de las características clínico epidemiológicas más comunes fue la disnea. En los resultados correlaciónales se encontró que las características clínico epidemiológicas y el IMC se relacionan estadísticamente con la mortalidad después de usar Ventilación Mecánica Invasiva (VMI), existe influencia entre el sobrepeso, la obesidad y la mortalidad.

La obesidad y el sobrepeso se consideran un problema de salud pública, afecta a personas de varias edades y estratos sociales, por el desorden en la forma de alimentarse o por desinformación, constituye un factor que incide sobre el manejo de los pacientes que presentan problemas respiratorios y que requieren apoyo de ventilación mecánica, este problema se evidencia especialmente en los últimos tiempos en que se han incrementado el número de pacientes por la pandemia. Objetivo: Determinar la influencia de la obesidad en la evaluación de mortalidad en pacientes sometidos a ventilación mecánica invasiva. Material y Método: Se realizó un estudio en los pacientes del área de terapia intensiva del Hospital Luis Vernaza ingresados en el periodo desde marzo 2020 hasta marzo 2021 entre las edades de 16 y 90 años. Se utilizó las historias clínicas digitalizadas del programa SERVINTER CLINICAL SUITE (HC MEDICA – 2.6) – (Evolución Médica – 2.6.2 (chievomed) Conclusión: Los resultados reflejaron que la mayoría de los pacientes fueron personas adultas mayores y del género masculino así también Una de las características clínico epidemiológicas más comunes fue la disnea. En los resultados correlaciónales se encontró que las características clínico epidemiológicas y el IMC se relacionan estadísticamente con la mortalidad después de usar Ventilación Mecánica Invasiva (VMI), existe influencia entre el sobrepeso, la obesidad y la mortalidad.

Autism spectrum disorder (ASD) is clinically characterized by social and communication difficulties as well as repetitive behaviors. Many children with ASD also suffer from anxiety, which has been associated with alterations in amygdala structure. In this work, the association between amygdala subnuclei volumes and anxiety was assessed in a cohort of 234 participants (mean age = 11.0 years, SD = 3.9, 95 children with ASD, 139 children were non-autistic). Children underwent magnetic resonance imaging. Amygdala subnuclei volumes were extracted automatically. Anxiety was assessed using the Screen for Child Anxiety Related Disorders, the Child Behavior Checklist, and the Strength and Difficulties Questionnaire. Children with ASD had higher anxiety scores relative to non-autistic children on all anxiety measures (all, p Lay abstract Autism spectrum disorder (ASD) is clinically characterized by social communication difficulties as well as restricted and repetitive patterns of behavior. In addition, children with ASD are more likely to experience anxiety compared with their peers who do not have ASD. Recent studies suggest that atypical amygdala structure, a brain region involved in emotions, may be related to anxiety in children with ASD. However, the amygdala is a complex structure composed of heterogeneous subnuclei, and few studies to date have focused on how amygdala subnuclei relate to in anxiety in this population. The current sample consisted of 95 children with ASD and 139 non-autistic children, who underwent magnetic resonance imaging (MRI) and assessments for anxiety. The amygdala volumes were automatically segmented. Results indicated that children with ASD had elevated anxiety scores relative to peers without ASD. Larger basal volumes predicted greater anxiety in children with ASD, and this association was not seen in non-autistic children. Findings converge with previous literature suggesting ASD children suffer from higher levels of anxiety than non-autistic children, which may have important implications in treatment and interventions. Our results suggest that volumetric estimation of amygdala’s subregions in MRI may reveal specific anxiety-related associations in children with ASD.

Fetal functional magnetic resonance imaging (fMRI) offers critical insight into the developing brain and could aid in predicting developmental outcomes. As the fetal brain is surrounded by heterogeneous tissue, it is not possible to use adult- or child-based segmentation toolboxes. Manually-segmented masks can be used to extract the fetal brain; however, this comes at significant time costs. Here, we present a new BIDS App for masking fetal fMRI, funcmasker-flex, that overcomes these issues with a robust 3D convolutional neural network (U-net) architecture implemented in an extensible and transparent Snakemake workflow. Open-access fetal fMRI data with manual brain masks from 159 fetuses (1103 total volumes) were used for training and testing the U-net model. We also tested generalizability of the model using 82 locally acquired functional scans from 19 fetuses, which included over 2300 manually segmented volumes. Dice metrics were used to compare performance of funcmasker-flex to the ground truth manually segmented volumes, and segmentations were consistently robust (all Dice metrics ≥0.74). The tool is freely available and can be applied to any BIDS dataset containing fetal bold sequences. funcmasker-flex reduces the need for manual segmentation, even when applied to novel fetal functional datasets, resulting in significant time-cost savings for performing fetal fMRI analysis.

The symptoms of hyperactivity-impulsivity and inattention displayed by children with ADHD put them at risk of experiencing peer victimization. Hippocampal maturation, may reduce a child’s vulnerability to the experience of peer victimization, as it has been associated with decreased ADHD symptomatology. Working memory is an important executive function in the formation and maintenance of social relationships, which is often impaired in ADHD. We aimed to evaluate the relationship between problem behaviours, peer victimization, hippocampal morphology, and working memory in children with and without ADHD. 218 typically-developing participants (50.5% male) and 232 participants diagnosed with ADHD (77.6% male) were recruited. The ADHD group was subdivided into inattentive (ADHD-I) or combined (ADHD-C) types. The Child Behavior Checklist measured problem behaviours and peer victimization. Children underwent Magnetic Resonance Imaging (MRI). Hippocampal subfield volumes were obtained using FreeSurfer. The Wechsler Intelligence Scale for Children-fifth edition measured working memory (WM). The ADHD-C group displayed significantly higher levels of problem behaviours and peer victimization (all, p p p

Study Design: Free fibula flaps are nowadays the gold standard for the surgical reconstruction on large mandibular defects. Malocclusion is an important complication of this type of reconstruction and many of these patients end up requiring subsequent orthognathic corrective surgery. This is a descriptive retrospective case series study. Objective: To describe the demographic data, operative techniques, corrective methods and postoperative results in the management of malocclusion following mandibular reconstruction with free fibula flap. Methods: This case series study included patients who underwent free fibula flap mandibular reconstructions and who that subsequently developed malocclusion requiring orthognathic corrective surgery, from June 2010 to December 2019. Panoramic X-rays, cephalometries and/or 3-D facial reconstruction CT scans were used for surgical planning to create surgical cutting guides, templates and occlusal splints in all the patients that underwent corrective orthognathic surgery. Results: There were 46 patients who underwent a free fibula flap mandibular and maxillary reconstruction at San Jose Hospital between June 2010 and December 2019 of these, 5 patients (10.9%) developed postoperative malocclusion. One case from another institution was added to this study for a total of 6 patients with malocclusion following mandibular reconstruction surgery with a fibula free flap. During the orthognathic surgery, vertical osteotomies were performed in 3 patients and bilateral sagittal split osteotomies were necessary in 2 patients and L-shape in 1 patient. Osteogenic distraction was performed in 3 patients as part of their orthognathic treatment. The fixation methods were based in miniplates for 3 of the patients and lag screws for the remaining 3 patients. With this approach, all patients had an adequate occlusion correction with a 100% consolidation at their 6-month follow up. Conclusion: Malocclusion is a significant complication following mandibular reconstruction surgery that must be identified and managed. In severe cases, it requires corrective orthognathic surgery in severe cases. We have developed a protocol to avoid pitfalls during the primary reconstruction and in case an orthognathic surgery is required for malocclusion correction, preoperative planning with cutting guides and occlusal splints should be assessed, to guarantee favorable results through a reproducible technique.

Tropical and subtropical ecosystems are widely affected by the expansion of agriculture over pristine lands. Despite research efforts, knowledge of the impact of land-use change on soil is still limited by intrinsic variability, inconsistent results and inadequate replication. This study aimed to better understand the consequences of land-use change by focusing on long-term effects on both soil biotic and abiotic parameters. For this purpose, we selected three productive farms under similar management, each of them with pristine forest sites and agricultural sites that had been deforested for ~15 and ~30 years. In each site, we analysed soil microbiological (phospholipid fatty acids [PLFAs], biomass and activity) and physicochemical parameters. Long-term land-use change caused a detriment in soil microbial biomass, activity and fungal abundance, but only small changes in PLFA composition. In fact, PLFA composition was more affected by soil physicochemical properties such as carbon-to-nutrient ratios and labile carbon than by land use. Some physicochemical parameters (e.g., organic carbon and nutrients) were also negatively affected by land-use change and were more sensitive to time under agricultural use than microbiological parameters. The lower sensitivity of microbiological parameters could be the result of severe drought conditions at sampling, which may have affected soil microbial communities in both land uses. We were also able to detect associations between specific microbiological and physicochemical parameters. Among these, we identified some that seemed to result from their co-variation in response to land-use change and others that seemed to be independent of land use. Overall, our results show that soils can suffer further deterioration several years after deforestation. In order to restore soil health in these degraded lands, we need to keep on investigating the physical, chemical and biological mechanisms responsible for this deterioration. Highlights: Land-use change affected soil microbiological and physicochemical parameters. Microbiological parameters seemed to stabilize after continuous agriculture. Soil organic C, total N and fine particles were still reduced after long-term cultivation. Microbiological parameters were mostly associated with C-to-nutrient ratios and labile C. Drought conditions may have affected microbial response to land-use change. Fil: Tosi, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Chludil, Hugo Daniel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos; Argentina Fil: Correa, Olga Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Vogrig, Jimena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Montecchia, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina

Este estudio tuvo como objetivo describir los resultados clínicos del colgajo anterolateral de muslo y radial de antebrazo, para la reconstrucción hipofaríngea y esofágica en un hospital de cuarto nivel en Bogotá, Colombia.Estudio retrospectivo inlcuyo 38 pacientes a los que se les realizó reconstrucción funcional esofágica con colgajo de antebrazo radial o anterolateral de muslo (ALT) entre febrero de 2010 y diciembre de 2017.Edad media fue de 51 años. El 80% genero femeninp. Los defectos laringoesofágicos estuvieron presentes en el 80%. Se requirió reconstrucción circunferencial total en el 60% de los pacientes. Se realizaron injertos braquio-radiales en el 26% y colgajos anterolaterales de muslo en el 74%. La tasa global de complicaciones tempranas fue del 30%, de las cuales el 20% fueron fístulas (braquio-radial, 2,8%; colgajo libre de ALT, 8,3%). Las complicaciones tardías (20%) incluyeron estenosis y obstrucción de la luz del injerto distal. Solo el 10% de los pacientes no pudieron tolerar la alimentación oral y el 50% de este paciente necesitó gastrostomía permanente. En cuanto al seguimiento oncológico durante el postoperatorio de 24 meses, no se observó recidiva tumoral.Los resultados funcionales de la reconstrucción con colgajo braquio-radial y ALT fueron satisfactorios. Nuestros hallazgos sugieren que la ALT tiene una menor incidencia de complicaciones posoperatorias que el colgajo radial de antebrazo. La elección del tipo de colgajo dependerá del tamaño y la ubicación del defecto. Los defectos pequeños y parcialmente cubiertos se benefician del uso de un colgajo radial, y para reconstrucciones faríngeas más grandes y circunferenciales con posibles requisitos de radioterapia, se benefician de un colgajo ALT.This study aimed to describe clinical outcomes of anterolateral thigh (ALT) and radial forearm flap in hypopharyngeal and esophageal reconstruction in a fourth level hospital in Bogotá, Colombia.This retrospective study included 38 patients who esophageal functional reconstruction using radial forearm or ALT flap at our center between February 2010 and December 2017.Mean age was 51 years. About 80% of the included patients were females. Laryngoesophageal defects were present in 80%. Total circumferential reconstruction was required in 60% of patients. Brachial-radial grafts were performed in 26% and anterolateral thigh flaps in 74%. Overall, early complication rate was 30%, which 20% were fistulae (brachial-radial, 2.8%; ALT free flap, 8.3%). Late complications (20%) included stenosis and distal graft lumen obstruction. Only 10% of patients were unable to tolerate oral feeding and 50% of this patient needed permanent gastrostomy. Regarding oncological follow-up during the 24-month post-operative, no tumor recurrence was observed.Functional outcomes of reconstruction with brachial-radial and ALT flap were satisfying. Our findings suggest that ALT has a lower incidence of post-operative complications than radial forearm flap. The choice of the type of flap will depend on the size and location of the defect. Small and partially covered defects benefit from the use of a radial flap, and for larger and circumferential pharyngeal reconstructions with possible radiotherapy requirements, they benefit from an ALT flap.

Background Children with ADHD are at risk of experiencing peer victimization, which is associated with delayed brain development and cognitive difficulties. We aimed to evaluate the relationship between problem behaviours, peer victimization, hippocampal morphology, and working memory in children with and without ADHD. Methods 218 typically developing participants (50.5% male) and 232 participants diagnosed with ADHD (77.6% male) were recruited. The ADHD group was subdivided into inattentive (ADHD-I) or combined (ADHD-C) type. The Child Behaviour Checklist measured problem behaviours and peer victimization. Hippocampal subfield volumes were obtained using Magnetic Resonance Imaging and the Wechsler Intelligence Scale for Children-fifth edition measured working memory (WM). Results The ADHD-C group displayed significantly higher rates of problem behaviours and peer victimization (all, p

Clavibacter michiganensis subsp. michiganensis (Cmm) causes bacterial wilt and canker in tomato, producing important economic losses worldwide. Its virulence has been related to several putative virulence factors present on a chromosomal pathogenicity island and on plasmids pCM1 and pCM2, in strain NCPPB382. We genotypically characterized a collection of Cmm isolates from the main greenhouse tomato-producing areas of Argentina by BOX-PCR fingerprinting and screened for the presence of genes and plasmids involved in pathogenicity by PCR. In addition, we evaluated in vitro cellulolytic activity and virulence in planta of selected strains. BOX-PCR fingerprinting clustered strains into four groups. Group II was dominant and included the most virulent strains, while Group III was the smallest and had the least virulent strains. All local strains exhibited similar cellulolytic activity. Most of the examined strains carry two plasmids of similar size to those of NCPPB382, although there were strains with one or three plasmids. By PCR amplification of repA, pCM1 was detected only in strains belonging to Group III, which includes local strains closely related to reference strain NCPPB382. All analysed pathogenicity genes were widespread among strains, and so in strains belonging to Groups I and II, celA found on pCM1 in NCPPB382 could be found in the chromosome or in plasmids other than pCM1. This study contributes to a better understanding of the diversity of Cmm genetic profiles and virulence of strains present in Argentina. Such information could be useful for the selection of strains for screening of host resistance and development of resistant tomato varieties. Fil: Wassermann, Eliana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Montecchia, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Garaventa, Valeria Soledad. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina Fil: Correa, Olga Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Romero, Ana María. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina

A superior advantage of the superficial circumflex iliac artery perforator flap is that any donor site residue can easily be hidden by clothing. Usually designed as narrow or moderate-sized flaps based on medial perforators of the superficial branch, this readily allows primary donor site closure. However, for larger flaps, tension-free closure requires that the thigh remain flexed or even a skin graft used. Another alternative would be to use an adequate lateral perforator of the deep branch, if available, as the vascular hub of a propeller flap that extended into the adjacent flank, that could then be rotated into the medial groin to facilitate simultaneous direct closure of both flap donor sites.

Yeast cells can use γ-aminobutyric acid (GABA), a non-protein amino acid, as a nitrogen source that is mainly imported by the permease Uga4 and catabolized by the enzymes GABA transaminase and succinate-semialdehyde dehydrogenase, encoded by the UGA1 and UGA2 genes, respectively. The three UGA genes are inducible by GABA and subject to nitrogen catabolite repression. Hence, their regulation occurs through two mechanisms, one dependent on the inducer and the other on nitrogen source quality. The aim of this work was to better understand the molecular mechanisms of transcription factors acting on different regulatory elements present in UGA promoters, such as Uga3, Dal81, Leu3 and the GATA factors, and to establish the mechanism of the concerted action between them. We found that Gat1 plays an important role in the induction of UGA4 transcription by GABA and that Gzf3 has an effect in cells grown in a poor nitrogen source such as proline and that this effect is positive on UGA4 expression. We also found that Gln3 and Dal80 affect the interaction of Uga3 and Dal81 on UGA promoters. Moreover, our results indicated that the repressing activity of Leu3 on UGA4 and UGA1 occurs through Dal80 since we demonstrated that Leu3 facilitates Dal80 interaction with DNA. However, when the expression of GATA factors is null or negligible, Leu3 functions as an activator. Fil: Palavecino Ruiz, Marcos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Bermudez Moretti, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Correa Garcia, Susana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Land-use change has drastically reduced the area of pristine forests in tropical and subtropical regions. In NWArgentina, Yungas forests were among the most affected by deforestation for the implementation of agricultural crops. Conversion of forests to croplands modified the structure and function of soil microbial communities, but its effects on soil functionality across time after land-use change are understudied. Therefore, the objective of this study was to analyze the impact of land-use change and time under cultivation on the functionality of microbial communities in these soils. We established a 30- year old chronosequence comprising 4 stages (forest and short-, mid- and long-term agriculture) in 3 independent farms. Together with soil physicochemical properties, we measured microbial biomass carbon, basal respiration, ammonification, acid and alkaline phosphomonoesterase activities, and community-level physiological profiling (CLPP). During the first years of cultivation, the functionality and biomass of soil microbial communities were strongly affected. Compared to forest soils, short-term agricultural soils exhibited a reduction on microbial biomass ( 45%), ammonification ( 67%) and acid phosphomonoesterase activity ( 41%). Moreover, increased basal respiration (up to 94%) and metabolic quotient in those soils suggested radical changes in functionality at the beginning of the chronosequence. However, CLPP evidenced that older agricultural sites had an increased global catabolic response per unit biomass, while it detected no differences in physiological diversity of soil microbial communities along the chronosequence. The lack of differences detected between mid- and long-term agricultural sites, in addition to a reduced inter-site variability, evidences an apparent stabilization and homogenization of soil microbial communities towards the end of the chronosequence. In contrast with physicochemical variables, microbiological variables had a greater performance for characterizing the different stages of the agricultural chronosequence and the impact of land-use change on soil functionality. Fil: Tosi, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Correa, Olga Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Soria, Marcelo Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Vogrig, Jimena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Sydorenko, Oksana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Montecchia, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina

Dietary regimens have proven to promote longevity in several eukaryotic model organisms including the budding yeast Saccharomyces cerevisiae. These interventions are effective strategies for preventing ageing and diseases and many of them are linked to amino acid and protein levels. The aim of this work was to better understand how the age-related TOR1 and SCH9 genes and the presence of amino acids affect cell metabolomes and to establish their impact on the ageing process. Cellular metabolic profiles were determined by FTIR spectroscopy. We demonstrated that metabolic signatures of cells deficient in SCH9, the major TORC1 effector, were very different to those of wild type and TOR1 deficient cells. In cells lacking Sch9 we also observed changes in other processes related to ageing such as endoplasmic reticulum stress and autophagy. We identified several anti-ageing biomarkers being the most relevant the intracellular content of pyruvate, glucose, ribose/deoxyribose associated compounds, and the presence of special protein conformational structures. The very sensitive FTIR technique allowed us to highlight important changes that occur along ageing in the metabolomes of the cells deficient in the key nutrient-sensitive Tor1-Sch9 pathway, even though slight differences on chronological lifespan were detected in our conditions. Fil: Bermudez Moretti, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Gulias, Juan Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Valencia Guillen, Jenniffer. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Muñoz, Sebastian Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Forfar, Isabelle. Inserm; Francia Fil: Correa Garcia, Susana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Gene regulation in yeast occurs at the transcription level, i.e. the basal level of expression is very low and increased transcription requires gene-specific transcription factors allowing the recruitment of basal transcriptional machinery.

Transcription regulation of most genes in yeast occurs at the level of activation, i.e. the basal level of expression is very low and increased transcription requires gene-specific transcription factors allowing the recruitment of basal transcriptional machinery. Saccharomyces cerevisiae BAP2 gene encodes the permease responsible for the major part of leucine, valine and isoleucine uptake, amino acids that this yeast can use as nitrogen sources. Moreover, BAP2 expression is known to be induced by the presence of amino acids such as leucine. In this context, the current results show that BAP2 is an inducible gene in the presence of nitrogen-poor source proline but exhibits high constitutive non-inducible expression in nitrogen-rich source ammonium. BAP2 expression is regulated by the SPS sensor system and transcription factors Leu3, Gcn4 and Dal81 in both a direct and an indirect way depending on the quality of the nitrogen source. We further demonstrate here that a physical interaction occurs between Uga3 ‒the transcriptional activator responsible for γ-aminobutyric acid (GABA)-dependent induction of the GABA genes‒ and the regulatory region of the BAP2 gene, which leads to a strong positive regulation. Fil: Muñoz, Sebastian Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Gulias, Juan Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Valencia Guillen, Jenniffer. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Correa Garcia, Susana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Bermudez Moretti, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

The implementation of conservationist systems that improve soil properties and reduce the impacts of the conversion of native areas is fundamental for feasible agricultural exploitation. This study aimed to evaluate the impact on soil biological properties caused by the conversion of murundus fields into agricultural systems and verify the ability of the no-tillage conservation system to recover these properties over the years. Treatments consisted of three agricultural areas subjected to the same management (no-tillage), in a chronosequence (7, 11, and 14 years of conversion) and a reference area (murundus field). To evaluate soil quality, we analyzed total soil organic carbon, microbial biomass carbon, soil basal respiration, metabolic and microbial quotients, and acid phosphatase activities, as well as the potential functionality of soil bacterial communities and the modifications in their genetic structure. The conversion of murundus field into agricultural systems negatively impacted soil biological properties, with expressive reduction in soil organic carbon content and microbial biomass carbon. The periods of adoption of the conservationist system (no-tillage) were not enough to recover the biological properties and/or to reverse the changes observed in the genetic structure of the soil bacterial communities of the managed areas, although stabilization trends were observed in the agricultural systems over the years. Fil: Martins, Luciene Nunes Barcelos. Universidade Federal de Goiás; Brasil Fil: Santiago, Flávia Louzeiro de Aguiar. Universidad Federal de Lavras; Brasil Fil: Montecchia, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Correa, Olga Susana. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Junior, Orivaldo José Saggin. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: de Souza, Edicarlos Damacena. Universidade Federal do Mato Grosso do Sul; Brasil Fil: Paulino, Helder Barbosa. Universidade Federal Do Triangulo Mineiro; Brasil Fil: Carneiro, Marco Aurelio Carbone. Universidad Federal de Lavras; Brasil

Objective The Rosai-Dorfman disease (RDD) is a rare disorder known as sinus histiocytosis with massive lymphadenopathy which affects other organs besides the lymphatic nodes. The most frequent clinical presentation is the skin involvement, but the most serious one is when the central nervous system is compromised. There are not clinical cases in the literature reporting the mandibular involvement and its management. The aim of this study is to report the case of a patient with this disease, her treatment, and her follow-up. Study A 32-year-old woman with RDD, who underwent a right mandibulectomy to treat osteomyelitis, and who suffered hemolytic anemia, lymphoproliferative syndrome, and bacterial meningitis by meningococcus treated successfully, is presented. She also had osteosynthesis plate exposure in 3 occasions. The authors performed a mandibular reconstruction with a fibula free flap. Vertical osteogenic distraction was done to improve the vertical height of the bone for osteointegrated implants and later oral rehabilitation. Methods The senior authors performed mandibular reconstruction with a fibula free flap. Vertical osteogenic distraction was performed to improve the vertical height of the bone for osteointegrated implants and later oral rehabilitation. The patient achieved adequate function with a good mandibular height and occlusion. Results The patient had a follow-up of 6 months. She is highly satisfied with her result. Preoperative and postoperative photos are shown. Discussion In this rare case, the authors show the difficulties when treating this disease. The follow-up of the patient showed a successful reconstruction with good functional results.

Clavibacter michiganensis subsp. michiganensis causes bacterial wilt and canker in tomato. A detailed account of pathogen effects on growth and water parameters of affected plants is lacking. Besides, the long latent period of the disease represents a limitation for its management. Our objectives were to determine the physiological and morphological changes induced by this pathogen in tomato, in relation to water stress, and to evaluate two well-known leaf spectral reflectance indices for the diagnosis of this vascular disease before symptoms expression. Experiments were conducted in a greenhouse with pot-grown plants inoculated with a bacterial suspension (107 CFU/ml); controls were treated with sterile distilled water. Five weeks later plants were harvested and several growth parameters, the number and size of xylem vessels and the hydraulic conductivity of the stems were determined. Inoculated plants were shorter, with smaller leaf area and lower biomass than those of mock-inoculated plants. While the number and hydraulic radius of xylem vessels were not affected, the stem-specific (Ks) and the leaf-specific (KL) conductivity were significantly reduced by inoculation. Wilting of leaves of diseased plants was associated to the reduction of KL. Inoculated plants showed leaf spectral reflectance changes 1 week after inoculation, and 2 weeks before symptom expression, as shown by the index NDWI, an indicator of the water content of the leaves. We conclude that C. michiganensis subsp. michiganensis reduced the growth and altered plant-water relations of tomato plants by reducing the stem hydraulic conductivity. The NDWI index could be used for the early, non- destructive, diagnosis of bacterial canker. Fil: Romero, Ana M.. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina Fil: Vega, Damián. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina Fil: Pizzorno, Romina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina Fil: Cordon, Gabriela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Correa, Olga S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina

Fil: Behrends Kraemer, Filipe. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina. Fil: Montecchia, Marcela S. S. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina. Fil: Fernández, Patricia L. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina. Fil: Correa, Olga S. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina. Fil: Chagas, Celio I. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.

Tomato bacterial wilt and canker, caused by Clavibacter michiganensis subsp. michiganensis (Cmm) is considered one of the most important bacterial diseases of tomato worldwide. During the last two decades, severe outbreaks have occurred in greenhouses in the horticultural belt of Buenos Aires-La Plata, Argentina. Cmm strains collected in this area over a period of 14 years (2000–2013) were characterized for genetic diversity by rep-PCR genomic fingerprinting and level of virulence in order to have a better understanding of the source of inoculum and virulence variability. Analyses of BOX-, ERIC- and REP-PCR fingerprints revealed that the strains were genetically diverse; the same three fingerprint types were obtained in all three cases. No relationship could be established between rep-PCR clustering and the year, location or greenhouse origin of isolates, which suggests different sources of inoculum. However, in a few cases, bacteria with identical fingerprint types were isolated from the same greenhouse in different years. Despite strains differing in virulence, particularly within BOX-PCR groups, putative virulence genes located in plasmids (celA, pat-1) or in a pathogenicity island in the chromosome (tomA, chpC, chpG and ppaA) were detected in all strains. Our results suggest that new strains introduced every year via seed importation might be coexisting with others persisting locally. This study highlights the importance of preventive measures to manage tomato bacterial wilt and canker. Fil: Wassermann, Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina Fil: Montecchia, Marcela Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Correa, Olga Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Vega, Damián. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina Fil: Romero, Ana María. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología; Argentina

A B S T R A C T Water stress, with its negative consequences on plant growth and survival, can be mitigated by Azospirillum brasilense inoculation. In tomato, A. brasilense delays wilting caused by a vascular pathogen, Clavibacter michiganensis subsp. michiganensis, by yet unknown mechanisms. We studied morphological, anatomical and physiological changes induced by A. brasilense in tomato that relate to water stress tolerance, which could explain the deferral in symptom expression. For this purpose, tomato seeds were treated or not with A. brasilense BNM65, and 5 weeks later plants were challenged with C. michiganensis subsp. michiganensis or mock inoculated with water. There was a large growth promotion associated to Azospirillum: treated plants had higher total biomass and leaf area. In relation to water stress tolerance, Azospirillum treated plants had larger xylem vessel area, higher stem specific hydraulic conductivity, thicker stems, and lower shoot/root dry matter and specific leaf area. These changes were opposite to those induced by C. michiganensis subsp. michiganensis. We conclude that A. brasilense favoured a better adjustment of plant-water relations by several mechanisms, and thus, transitorily alleviated symptoms expression of a vascular disease.

The genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting, and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified as A. chroococcum, A. salinestris and A. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3)and zeatin (Z) biosynthesis, nitrogenase activity and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged the following concentrations: 2.2-20 µg IAA ml-1, 0.3-0.7 µg GA3 ml-1, 0.5-1.2 µg Z ml-1. Seed inoculations with further selected Azotobacter strains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solution but it was not related with bacterial root colonization. Our survey constitutes a first approach to the knowledge of Azotobacter species inhabiting Argentinean soils, in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection of Azotobacter strains for biofertilizer formulations. Fil: Rubio, Esteban Julio. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; Argentina; Fil: Montechia, Marcela Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiologia Agrícola; Argentina; Fil: Tosi, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina; Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiologia Agrícola; Argentina; Fil: Cassan, Fabricio Dario. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Cs.naturales. Laboratorio de Fisiologia Vegetal y de la Interaccion Planta-microorganismo; Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentina; Fil: Perticari, Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; Argentina; Fil: Correa, Olga Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiologia Agrícola; Argentina

BACKGROUND Reconstruction of the maxilla with the fibula free flap is a popular and well-described technique. The ideal intraoral lining would be mucosa, which is moist, thin, and non-hair-bearing. Prelamination of the fibula with buccal mucosa replaces like tissue with like tissue, obviates the need for a skin paddle, and facilitates placement of osseointegrated implants in a single stage. For central maxillary defects, the authors have shifted from using an osteocutaneous to a prelaminated free fibula flap. In this article, the authors report their experience using the prelaminated osteomucosal fibula for maxillary reconstruction. METHODS From 2003 to 2011, 24 patients underwent reconstruction of a central maxillary defect using a free fibula flap. The first 10 patients had osteoseptocutaneous flaps, and the other 14 patients had prelaminated flaps. Data collected included patient age, cause of defect, type and number of operations, complications at both the donor and recipient sites, and placement of osseointegrated implants. RESULTS The majority of patients in the series (n = 21) had central maxillary defects caused by loss of the premaxilla during early repair of bilateral cleft lip-cleft palate. There was one flap failure in the nonprelaminated flap group and one in the prelaminated group. Repeated debulking to thin the skin paddle was required in all of the patients with osteocutaneous flaps. CONCLUSIONS Prelamination delivers like tissue to the recipient site, obviates the need for debulking, and may reduce donor-site wound problems. To the authors' knowledge, this is the largest series of prelaminated fibulas for maxillary reconstruction in the literature. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.

Fil: Simonetti, Ester. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Biologia Aplicada y Alimentos. Catedra de Microbiologia Agricola; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agricolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomia. Instituto de Investigaciones en Biociencias Agricolas y Ambientales; Argentina

Land use effects on microbial communities may have profound impacts on agricultural productivity and ecosystem sustainability as they are critical in soil quality and health. The main aim of this study was to characterize the microbial communities of pristine and agricultural soils in the central Yungas region in Northwest Argentina. As a first step in the development of biological indicators of soil quality in this region, a comprehensive approach involving a structural and functional evaluation of microbial communities was used to detect changes in soil as consequence of land use. The sites selected included two pristine montane forest sites (MF1 and MF2), two plots under sugarcane monoculture for 40 and 100 years (SC40 and SC100), one plot under 20 years of soybean monoculture (SB20), a recently deforested and soybean cropped site (RC), and two reference sites of native forest adjacent to the sugarcane and soybean plots (PF1 and PF2). We used three microbial community profiling methods: denaturing gradient gel electrophoresis (DGGE) analysis of PCR amplified 16S rRNA genes, community-level physiological profiling (CLPP) using a BD oxygen biosensor system (BDOBS-CLPP) and phospholipid fatty acid (PLFA) analysis. Deforestation and agriculture caused expected increases in pH and decreases in organic carbon and microbial biomass. Additionally, shifts in the microbial community structure and physiology were detected with disturbance, including reduced diversity based on PLFA data. The higher respiratory response to several carbon substrates observed in agricultural soils suggested the presence of microbial communities with lower growth yield efficiency that could further reduce carbon storage in these soils. Using an integrated multivariate analysis of all data measured in this study we propose a minimum data set of variables (organic carbon, pH, sucrose and valeric acid utilizations, a17:0 and a15:0 PLFA biomarkers and the value of impact on microbial diversity) to be used for future studies of soil quality in Northwest Argentina.

Cool-season grasses commonly harbor fungal endophytes in their aerial tissues. However the effects of these symbionts on soil microbial communities have rarely been investigated. Our objective was to explore microbial community responses in soils conditioned by plants of the annual grass Lolium multiflorum with contrasting levels of infection with the endophyte Neotyphodium occultans. At the end of the host growing season, we estimated the functional capacity of soil microbial communities (via catabolic response profiles), the contribution of fungi and bacteria to soil activity (via selective inhibition with antibiotics), and the structure of both microbial communities by molecular analyses. Soil conditioning by highly infected plants affected soil catabolic profiles and tended to increase soil fungal activity. We detected a shift in bacterial community structure while no changes were observed for fungi. Soil responses became evident even without changes in host plant biomass or soil organic carbon or total nitrogen content, suggesting that the endophyte modified host rhizodepositions during the conditioning phase. Our results have implications for the understanding of the reciprocal interactions between above and belowground communities, suggesting that plant-soil feedbacks can be mediated by this symbiosis.

The increase in soybean productivity has contributed to a greater use of agrochemicals, which cause major problems, such as soil and water pollution and reduction of biodiversity, and have a negative impact on non-target species. The development of microbial biocontrol agents for soybean diseases can help to reduce pesticide abuse. Bacillus amyloliquefaciens BNM122 is a potential microbial biocontrol agent able to control the damping-off caused by Rhizoctonia solani when inoculated in soybean seeds, both in a plant growth chamber and in a greenhouse. In this study, we report the effect of soybean seed treatments with strain BNM122 or with two fungicides (thiram and carbendazim) on the structure and function of the bacterial community that colonizes the soybean rhizosphere. Also, soybean root nodulation by Bradyrhizobium japonicum , mycorrhization by arbuscular mycorrhizal fungi and plant growth were evaluated. We used the r - and K -strategist concept to evaluate the ecophysiological structure of the culturable bacterial community, community-level physiological profiles (CLPP) in Biolog™ EcoPlates to study bacterial functionality, and the patterns of 16S RNA genes amplified by PCR and separated by denaturing gradient gel electrophoresis (PCR–DGGE) to assess the genetic structure of the bacterial community. Neither the ecophysiological structure nor the physiological profiles of the soybean rhizosphere bacterial community showed important changes after seed inoculation with strain BNM122. On the contrary, seed treatment with fungicides increased the proportions of r -strategists and altered the metabolic profiles of the rhizosphere culturable bacterial community. The genetic structure of the rhizosphere bacterial community did not show perceptible changes between treated and non-treated seeds. Regarding the bacterial and fungal symbioses, seed treatments did not affect soybean nodulation, whereas soybean mycorrhization significantly decreased ( P It can be concluded that soybean seed treatment with B. amyloliquefaciens BNM122 had a lesser effect on soil microbial community than that with the fungicides, and that these differences may be attributed to the less environmental persistence and toxic effects of the strain, which deserve further studies in order to develop commercial formulations.

The Southern Andean Yungas in Northwest Argentina constitute one of the main biodiversity hotspots in the world. Considerable changes in land use have taken place in this ecoregion, predominantly related to forest conversion to croplands, inducing losses in above-ground biodiversity and with potential impact on soil microbial communities. In this study, we used high-throughput pyrosequencing of the 16S ribosomal RNA gene to assess whether landuse change and time under agriculture affect the composition and diversity of soil bacterial communities. We selected two areas dedicated to sugarcane and soybean production, comprising both short- and long-term agricultural sites, and used the adjacent native forest soils as a reference. Land-use change altered the composition of bacterial communities, with differences between productive areas despite the similarities between both forests. At the phylum level, only Verrucomicrobia and Firmicutes changed in abundance after deforestation for sugarcane and soybean cropping, respectively. In cultivated soils, Verrucomicrobia decreased sharply (;80%), while Firmicutes were more abundant. Despite the fact that local diversity was increased in sugarcane systems and was not altered by soybean cropping, phylogenetic beta diversity declined along both chronosequences, evidencing a homogenization of soil bacterial communities over time. In spite of the detected alteration in composition and diversity, we found a core microbiome resistant to the disturbances caused by the conversion of forests to cultivated lands and few or none exclusive OTUs for each land-use type. The overall changes in the relative abundance of copiotrophic and oligotrophic taxa may have an impact in soil ecosystem functionality. However, communities with many taxa in common may also share many functional attributes, allowing to maintain at least some soil ecosystem services after forest conversion to croplands. Fil: Montecchia, Marcela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Tosi, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Soria, Marcelo Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Vogrig, Jimena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Sydorenko, Oksana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina Fil: Correa, Olga Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina

Yeast can use a wide variety of nitrogen compounds. However, the ability to synthesize enzymes and permeases for catabolism of poor nitrogen sources is limited in the presence of a rich one. This general mechanism of transcriptional control is called nitrogen catabolite repression. Poor nitrogen sources, such as leucine, γ-aminobutyric acid (GABA), and allantoin, enable growth after the synthesis of pathway-specific catabolic enzymes and permeases. This synthesis occurs only under conditions of nitrogen limitation and in the presence of a pathway-specific signal. In this work we studied the temporal order in the induction of AGP1, BAP2, UGA4, and DAL7, genes that are involved in the catabolism and use of leucine, GABA, and allantoin, three poor nitrogen sources. We found that when these amino acids are available, cells will express AGP1 and BAP2 in the first place, then DAL7, and at last UGA4. Dal81, a general positive regulator of genes involved in nitrogen utilization related to the metabolisms of GABA, leucine, and allantoin, plays a central role in this coordinated regulation. Fil: Palavecino Ruiz, Marcos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Correa Garcia, Susana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Bermudez Moretti, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Azospirillum has been one of the most studied genera of plant growth promoting rhizobacteria (PGPR) worldwide over the past 50 years. The use of these microorganisms in agriculture practices has been adopted due to their ability to associate in rhizospheric, epiphytic, or endophytic ways with roots and promote whole plant growth or crop productivity. The biological treatment of seeds (inoculation) in more than a hundred species of economic or ecological interest has become a common practice in many countries. In Argentina, the Az39 strain of Azospirillum brasilense, belonging to the Culture Collection of the Instituto de Microbiologia y Zoologia Agricola (IMYZA) of INTA Castelar, was selected in the 1980s after an intensive program to isolate and identify microorganisms for agriculture, according to their agronomic behavior. Since then, its ability to cover the premise for which it was selected has determined that Az39 is largely adopted by inoculant companies in Argentina with the aim of producing biological products for the treatment of several crops. In this chapter, those methods developed and standardized by the network Red de Control de Calidad de Inoculantes (REDCAI) of the Asociacion Argentina de Microbiologia (AAM) have been adapted as a guide for the quantification of Azospirillum spp. and the detection of contaminating microorganisms in biological products, as two of the most basic and important quality control parameters of inoculants.

Salinity and drought induce osmotic stress in plants and nodulating bacteria. The introduction of soybean in areas with higher soil salt contents or periods of drought pose a challenge for the rhizobial inoculants used to improve nodulation and enhance nitrogen fixation. Bradyrhizobium japonicum is a slow-growing rhizobium used for soybean inoculation that was previously regarded as salt-sensitive. We tested the survival ability of cultures of B. japonicum E109 at the exponential and stationary phases of growth in liquid culture medium against different concentrations of NaCl. We found that stationary-phase cells could tolerate higher levels of salt than exponential-phase cells. This result suggested that the physiological manipulation of the cultures could improve the salt tolerance of this strain. Nonetheless, we also found that exponential-phase cells adapted significantly better to two key situations that a commercial product must face, survival in liquid formulations and survival in soil microcosms resembling conditions of drought. These results suggest that the use of actively growing cells could be an improvement in the production of inoculants. However, it is not cost-effective, because bacteria should be harvested at a time when cell density is lower than that of early stationary-phase cultures, which are normally used in the industry. To overcome this drawback we proved that a fed-batch system can produce exponential-phase cultures with higher cell densities and able to produce liquid inoculants with acceptable survival rates.

Aims: A bacterial strain producing antifungal compounds active against the plant pathogenic fungi Fusarium, Rhizoctonia and Sclerotinia has been characterized and shown to control Rhizoctonia root rot of soya bean. Methods and Results: The metabolites excreted by Bacillus BNM 122 remained active after autoclaving, were resistant over a wide pH range and to hydrolytic enzymes. By 1H-NMR and thin-layer chromatography analyses surfactin and iturin-like compounds were partially identified. Moreover, soya bean seeds bacterization with BNM 122 in a compost-based formulation was as effective controlling Rhizoctonia solani as pentachloronitrobenzene. According to its 16S rDNA sequence BNM 122 was closely related to Bacillus amyloliquefaciens and Bacillus subtilis. PCR analysis of the 16S-23S rRNA intergenic spacer region and repetitive sequence-based PCR (rep-PCR) genomic fingerprinting revealed a close genetic relationship to B. amyloliquefaciens. However, by physiological characterization using API tests, this strain resembled more B. subtilis. Conclusions: This is the first report describing the co-production of surfactin and iturin-like compounds by a putative strain of B. amyloliquefaciens. The synergistic effect of both lipopetides is a remarkable trait for a candidate biocontrol agent. Significance and Impact of the Study: This kind of research has relevance in order to minimize the use of synthetic fungicides and surfactants, contributing to the preservation of the environment.

Background and aims: biological processes in all organisms are controlled by environmental conditions, however, information concerning the molecular responses to external pH is scarce. In this work we studied the pH response of UGA4 gene encoding -aminolevulinic acid and -aminobutyric acid permease in Saccharomyces cere isiae. Methods: we analyzed the effect of pH on the expression of UGA4 gene measuring -galactosidase activity in cells carrying a UGA4::lacZ fusion gene. Results: results indicate that UGA4 expression is higher at acidic pH. The expression of UGA3 and UGA35 genes, which encode two positive transcription factors, is not regulated by external pH, while the expression of UGA43 gene encoding a repressor of UGA4 transcription is dependent on pH. Using a strain lacking Uga43p we clearly showed that the effect of ambient pH on UGA4 expression is not a secondary effect of the pH regulation on UGA43. We have also demonstrated that the effect of pH can only be detected when UGA4 gene is not subject to a strong repression by Uga43p nor to GABA induction. Conclusion: here, we demonstrate that UGA4 is an acid-expressed gene. This regulation is probably mediated by Rim101p through the consensus site 5-GCCARG-3 at 237 bp preceding the UGA4 coding sequence. Fil: Bermudez Moretti, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina Fil: Batlle, Alcira María del C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina Fil: Correa Garcia, Susana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

A study was conducted to compare the responses to acid pH of Medicago sativa and Lotus glaber, two forage legumes with different environmental requirements, either supplied with inorganic nitrogen (N) or inoculated with different strains of their nodule bacteria. Medicago sativa showed, in both treatments, a significant reduction in total dry weight at pH below 6.0. In contrast, Lotus glaber grew equally well at all the pHs assayed in the presence of adequate N. Under inoculated conditions, in the absence of N supply, plant growth was dependent on the bacterial strain used. When the ability of each strain to multiply in culture medium was examined, it was observed that Sinorhizobium meliloti strains showed a pH-sensitive response that inhibited growth at pH 4.0, whereas Mesorhizobium loti strains showed normal growth at this pH. These results suggest that for the effectiveness of Mesorhizobium loti–Lotus glaber symbiosis in acid soils the major factor to be considered is the tolerance of the bacterial str...