Friends or foes in the rhizosphere: traits of fluorescent Pseudomonas that hinder Azospirillum brasilense growth and root colonization

Bacteria of the Azospirillum and Pseudomonas genera are ubiquitous members of the rhizosphere, where they stimulate plant growth. Given the outstanding capacity of pseudomonads to antagonize other microorganisms, we analyzed the interaction between these two bacterial groups to identify determinants of their compatibility. We could establish that, when in direct contact, certain Pseudomonas strains produce lethality on Azospirillum brasilense cells using an antibacterial type 6 secretion system. When analyzing the effect of Pseudomonas spp. diffusible metabolites on A. brasilense growth on King´s B medium, we detected strong inhibitory effects, mostly mediated by siderophores. On Congo Red medium, both inhibitory and stimulatory effects were induced by unidentified compounds. Under this condition, Pseudomonas protegens CHA0 produced a Gac/Rsm-regulated antibiotic which specifically inhibited A. brasilense Sp7 but not Sp245. This effect was not associated with the production of 2,4-diacetylphloroglucinol. The three identified antagonism determinants were also active in vivo, producing a reduction of viable cells of A. brasilense in the roots of wheat seedlings when co-inoculated with pseudomonads. These results are relevant to the understanding of social dynamics in the rhizosphere and might aid in the selection of strains for mixed inoculants.Fil: Maroniche, Guillermo Andrés. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Diaz, Pablo Rafael. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Borrajo, María Paula. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Valverde, Claudio Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Creus, Cecilia Mónica. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Taking care of kidney transplant recipients during the COVID-19 pandemic: experience from a medicalized hotel.

The global overload that health systems are undergoing since the start of the COVID-19 pandemic has forced hospitals to explore sustainable alternatives to treat vulnerable patients that require closer monitoring and higher use of resources, such as Kidney Transplant Recipients (KTRs)1,2 .The use of telemedicine and hospital-like infrastructures represent a valid option for most patients with mild-moderate COVID-19, as well as for patients in the recovery phase who cannot be discharged from hospital

Brain energy rescue:an emerging therapeutic concept for neurodegenerative disorders of ageing

The brain requires a continuous supply of energy in the form of ATP, most of which is produced from glucose by oxidative phosphorylation in mitochondria, complemented by aerobic glycolysis in the cytoplasm. When glucose levels are limited, ketone bodies generated in the liver and lactate derived from exercising skeletal muscle can also become important energy substrates for the brain. In neurodegenerative disorders of ageing, brain glucose metabolism deteriorates in a progressive, region-specific and disease-specific manner — a problem that is best characterized in Alzheimer disease, where it begins presymptomatically. This Review discusses the status and prospects of therapeutic strategies for countering neurodegenerative disorders of ageing by improving, preserving or rescuing brain energetics. The approaches described include restoring oxidative phosphorylation and glycolysis, increasing insulin sensitivity, correcting mitochondrial dysfunction, ketone-based interventions, acting via hormones that modulate cerebral energetics, RNA therapeutics and complementary multimodal lifestyle changes

The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

Estudi del paper de les permeases de la família AAP de tomaca (Solanum lycopersicum L.) en la partició d'aminoàcids per a producció de fruit. Relació amb l'aportació de nitrogen a la planta

[ES] La familia de permeasas AAP se ha descrito como clave en la partición de aminoácidos en Arabidopsis y cultivos como el guisante o el arroz. Sin embargo, hay muy poca información sobre el papel de las AAPs en especies de fruto carnoso como el tomate (Solanum lycopersicum L.), principal cultivo de hortalizas a nivel mundial. En este trabajo, se ha realizado una caracterización inicial de las distintas permeasas descritas en tomate, estudiando su expresión génica en distintos órganos, que estaría relacionada con su posible papel en la carga de aminoácidos al floema en hoja, así como en la descarga al fruto. Asimismo, se ha estudiado la variabilidad existente de su expresión en hoja entre cultivares con conocidas diferencias en la eficiencia en el uso del N (NUE), así como el efecto de una reducción de la fertilización nitrogenada. Con respecto a la carga de aminoácidos en hoja, se ha observado la existencia de variabilidad en la expresión de estas permeasas entre distintas accesiones de tomate. Hay que señalar que, aunque existe variabilidad entre genotipos, las permeasas AAP2 y AAP4 son las que se expresan mayoritariamente en todos ellos, siendo posiblemente las principales responsables de la carga del floema en hoja. En condiciones limitantes de N, cobra especial interés la permeasa AAP6 que presenta un aumento de expresión en todas las accesiones estudiadas. Además, en estas condiciones de cultivo, existe una correlación con la producción y el tamaño de fruto. El estudio de las permeasas implicadas en la descarga de aminoácidos a las distintas partes del fruto, en la variedad Moneymaker, revela que también en este órgano son las permeasas AAP2 y AAP4 las que se expresan mayoritariamente y, por tanto, aquellas responsables de la descarga del floema al fruto. En su conjunto, estos estudios preliminares han permitido identificar diversos genes AAPs con funciones relevantes en procesos tanto de carga como descarga de aminoácidos, así como en la respuesta a la deficiencia del nitrógeno. En el contexto actual de necesaria reducción de la aplicación de fertilizantes nitrogenados en agricultura, todos ellos podrían ser dianas de futuros programas de mejora de la NUE. Los objetivos de este trabajo se relacionan con los siguientes ODS de la Agenda 2030: ODS 6. Agua limpia y saneamiento, ODS 12. Producción y consumo responsables, ODS 14. Vida submarina y ODS 15. Vida de ecosistemas terrestres.[EN] The AAP family of permeases has been described as key in the partitioning of amino acids in Arabidopsis and crops such as pea or rice. However, little is known about the role of AAPs in fleshy fruit species such as tomato (Solanum lycopersicum L.), the main vegetable crop worldwide. In this work, an initial characterization of the different permeases described in tomato has been carried out, studying their gene expression in different organs, which would be related to their possible role in the load of amino acids to the phloem in leaves, as well as in the discharge to the fruit. Likewise, the existing variability of its expression in leaves among cultivars with known differences in N use efficiency (NUE), as well as the effect of a reduction in nitrogen fertilization, has been studied. Regarding the load of amino acids in leaves, the existence of variability in the expression of these permeases among different tomato accessions has been observed. It should be noted that, although there is variability between genotypes, the AAP2 and AAP4 permeases are the ones that are most expressed in all of them, possibly being the main responsible for the phloem load in leaves. Under limiting conditions of N, the AAP6 permease is of special interest, which presents an increase in expression in all the accessions studied. Also, under these growing conditions, there is a correlation with production and fruit size. The study of the permeases involved in the release of amino acids to the different parts of the fruit, in the Moneymaker variety, reveals that the AAP2 and AAP4 permeases are also the most expressed in this organ and, therefore, those responsible for the release from phloem to fruit. Taken together, these preliminary studies have allowed the identification of various AAPs genes with relevant functions in processes of both loading and unloading of amino acids, as well as in the response to nitrogen deficiency. In the current context of necessary reduction in the application of nitrogenous fertilizers in agriculture, all of them could be targets of future improvement programs of the NUE. The objectives of this work are related to the following SDGs of the 2030 Agenda: SDG 6. Clean water and sanitation, SDG 12. Responsible consumption and production, SDG 14. Life below water and SDG 15. Life on land.Carreres Creus, P. (2023). Estudio del papel de las permeasas de la familia AAP de tomate (Solanum lycopersicum L.) en la partición de aminoácidos para producción de fruto. Relación con el aporte de nitrógeno a la planta. Universitat Politècnica de València. http://hdl.handle.net/10251/19596

Potencial de rizobacterias nativas de Argentina para el control de Meloidogyne javanica

Biocontrol of the nematode Meloidogyne javanica was studied using the Argentinean strains Pseudomonas fluorescens MME3, TAE4, TAR5 and ZME4 and Bacillus sp. B7S, B9T and B19S. Pseudomonas protegens CHA0 was used as a positive control. Egg hatching and juvenile mortality were evaluated in vitro by exposure of nematodes to bacterial suspensions or their cell-free supernatants (CFS). The effect of bacteria on nematode infestation of lettuce was also studied. results showed that most of the tested strains and CFS reduced egg hatching and juvenile survival in vitro. The bacterial suspension of Bacillus sp. B9T produced the lowest hatching of eggs. Juvenile mortality was higher when M. javanica was exposed to Bacillus sp. than to Pseudomonas spp. suspensions. Except for CFS of B9T, all filtrates inhibited hatching at levels similar to or higher than the biocontrol strain P. protegens CHA0. The CFS of CHA0 showed the highest level of juvenile mortality followed by Bacillus sp. strains and P. fluorescens TAE4. None of the inoculated rhizobacteria reverted the negative effect of infestation on the aerial dry weight of lettuce plants. However, inoculation impacted on reproduction of M. javanica by reducing the development of galls and egg masses on roots and diminishing the number of individuals both on roots and in the substrate, as well as the reproduction factor. These results show that most of the analyzed native strains can control the nematode M. javanica. Among them, P. fluorescens TAE4 and Bacillus sp. B9T showed the most promising performances for the biocontrol of this pathogen and have a potential use in the formulation of commercial products.Fil: Borrajo, María Paula. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Mondino, Eduardo Ariel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Maroniche, Guillermo Andrés. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Fernández, Macarena. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Creus, Cecilia Mónica. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

A novel, green, low-cost chitosan-starch hydrogel as potential delivery system for plant growth-promoting bacteria

The study examines the use of macrobeads for the controlled-release of bacteria. Macrobeads were prepared by an easy dripping-technique using 20/80 wt/wt chitosan-starch blends and sodium tripolyphosphate as cross-linking agent. The resulting polymeric matrix was examined by SEM, XRD, TGA, and solid-RMN. The swelling-equilibrium, thermal behaviour, crystallinity, and size of macrobeads were affected by the autoclave-sterilization. The diameter of the sterilized xerogel was c.a. 1.6 mm. The results suggested that ionotropic-gelation and neutralization were the mechanisms underlying hydrogel formation. Plant growth-promoting bacteria (PGPB) were loaded into macrobeads separately or co-inoculated. Bacteria loaded macrobeads were dried and stored. Bacteria survived at least 12 months in orders of 109 CFU of A. brasilense/g and 108 CFU of P. fluorescens/g. Bacterial release in sterile saline solution tended to a super Case-II transport mechanism. Polymeric-matrix release efficiently both PGPB in natural soils, which uncovers their potential for the formulation of novel and improved biofertilizers.Fil: Perez, J.J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química. Grupo de Aplicaciones de Materiales Biocompatibles; ArgentinaFil: Francois, N.J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química. Grupo de Aplicaciones de Materiales Biocompatibles; ArgentinaFil: Maroniche, Guillermo Andrés. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Borrajo, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Pereyra, M.A.. Universidad Nacional de Mar del Plata; ArgentinaFil: Creus, Cecilia Mónica. Universidad Nacional de Mar del Plata; Argentin

Revaluation of waste from fishing industry through generation of chitosan coatings to improve quality and extend shelf-life of minimally processed lettuce

Chitosan is obtained at industrial scale through a process of alkaline deacetylation of chitin the major waste of shrimp industry. Its utilization could both diminish industrial environmental impact and add value to foods and other industrial products. In this study, an industrial chitosan obtained in Argentina and a commercial chitosan were physicochemically characterized and evaluated as edible coating for biopreservation of minimally processed lettuce. Based on Nuclear Magnetic Resonance, X-ray diffraction and thermogravimetric and viscosimetric assays we conclude that both biopolymers have similar molecular weight and deacetylation degree. The chitosan coatings were applied by spraying to lettuce leaves that had been removed and cleaned after the harvest. Each sample composed by four whole leaves, packed into a low-density polyethylene bag, was stored at 4 °C for 15 d. Microbial quality, weight and color losses, antioxidant contents, stomatal closure and sensorial attributes were evaluated during storage. An initial reduction of 2 log in molds and yeast counts were obtained for both types of chitosan coatings. As a result, the counts remained below the limit value of 6 log for 12 d in the chitosan coatings, while in the control samples this limit was reached 6 d after storage. Total mesophilic bacteria counts were also reduced by both types of chitosan coatings, keeping counts under the threshold value of 7 log for 12 d while in control samples this value was exceeded at 9 d. Both chitosans increased chlorophyll content, total phenolic compounds and antioxidant activity in lettuce leaves during the storage. Besides, the leaf weight loss was minimized by both chitosan coatings, in accordance to a higher proportion of stomatal partial closure as seen by SEM. The overall visual quality was not affected by chitosan coatings. In conclusion, the industrial chitosan showed similar effects on stored minimally processed lettuce than the commercial chitosan adding value to a material that is currently considered a waste.Fil: Fasciglione, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Galaburri, Gonzalo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Ingeniería en Alimentos; ArgentinaFil: Yommi, Alejandra Karina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Perez Bravo, Jonas Jose. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química. Grupo de Aplicaciones de Materiales Biocompatibles; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Ortueta, Rocio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Scampini, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Buffa, Lautaro Martín. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Borrajo, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Creus, Cecilia Mónica. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Electronic and magnetic properties of C₆₀ thin films under ambient conditions: A multitechnique study

The magnetic and electronic properties of thin C₆₀ films (film thickness ⩾ P4 ML) grown by sublimation in vacuum on oxidized Si, Au, highly oriented pyrolytic graphite and glass, and subsequently exposed to ambient conditions, are investigated by using a multitechnique approach. The films exhibit a structure consisting of nanometric aggregates, whose size increases with film thickness, irrespective of the substrate, although larger aggregates are found on Au substrates. The XPS data indicate no significant degradation of the C₆₀ films, even though significant amounts of oxygen are present. Magnetic properties are characteristic of C₆₀ films exposed to oxygen and light. In contrast, STS measurements show that the local electronic properties are similar to those reported for ultrathin films grown on the same substrates under vacuum. A detailed discussion on the effects of film-thickness and substrate-type on the C₆₀ film properties, under ambient conditions, is presented.Facultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada