Deciphering the symbiotic plant microbiome: Translating the most recent discoveries on rhizobia for the improvement of agricultural practices in metal-contaminated and high saline lands

Rhizosphere and plant-associated microorganisms have been intensely studied for their beneficial effects on plant growth and health. These mainly include nitrogen-fixing bacteria (NFB) and plant-growth promoting rhizobacteria (PGPR). This beneficial fraction is involved in major functions such as plant nutrition and plant resistance to biotic and abiotic stresses, which include water deficiency and heavy-metal contamination. Consequently, crop yield emerges as the net result of the interactions between the plant genome and its associated microbiome. Here, we provide a review covering recent studies on PGP rhizobia as effective inoculants for agricultural practices in harsh soil, and we propose models for inoculant combinations and genomic manipulation strategies to improve crop yield

Activation of carbon dioxide and carbon disulfide by a scandium N-heterocyclic carbene complex

A Sc NHC complex readily activates three equivalents of CO2 showing ‘Frustrated Lewis Pair’ type reactivity with each metal–carbene bond, but whilst CS2 is also activated by the labile carbenes, no metal involvement is observed. Graphical abstract: Activation of carbon dioxide and carbon disulfide by a scandium N-heterocyclic carbene comple

Synthesis of Well-Defined, Surfactant-Free Co₃O₄ Nanoparticles:The Impact of Size and Manganese Promotion on Co₃O₄ Reduction and Water Oxidation Activity

Abstract: A surfactant-free synthetic route has been developed to produce size-controlled, cube-like cobalt oxide nanoparticles of three different sizes in high yields. It was found that by using sodium nitrite as salt-mediating agent, near-quantitative yields could be obtained. The size of the nanoparticles could be altered from 11 to 22 nm by changing the cobalt concentration and reaction time. These surfactant-free nanoparticles form ideal substrates for facile deposition of further elements such as manganese. The effect of size of the cobalt oxide nanoparticles and the presence of manganese on the reducibility of cobalt oxide to metallic cobalt was investigated. Similarly, the effect of these parameters was investigated with a visible light promoted water oxidation system with cobalt oxide as catalyst, together with [Ru(bpy) 3] 2+ light harvester dye and an electron acceptor. Graphical Abstract: A novel surfactant-free synthetic route has been developed to produce size-controlled, cube shaped cobalt oxide nanoparticles in high yields. [Figure not available: see fulltext.]. </p

Homo- and heteroleptic alkoxycarbene f-element complexes and their reactivity towards acidic N-H and C-H bonds

The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C–H and N–H bonds is described. The synthesis, characterisation and X-ray structures of the new heteroleptic mono- and bis(NHC) cyclopentadienyl complexes LnCp2(L) 1 (Ln = Sc, Y, Ce; L = alkoxy-tethered carbene [OCMe2CH2(1-C{NCHCHNiPr})]), LnCp(L)2 (Ln = Y) 2, and the homoleptic tetrakis(NHC) complex Th(L)44 are described. The reactivity of these complexes, and of the homoleptic complexes Ln(L)3 (Ln = Sc 3, Ce), with E–H substrates is described, where EH = pyrrole C4H4NH, indole C8H6NH, diphenylacetone Ph2CC(O)Me, terminal alkynes RC[triple bond, length as m-dash]CH (R = Me3Si, Ph), and cyclopentadiene C5H6. Complex 1-Y heterolytically cleaves and adds pyrrole and indole N–H across the metal carbene bond, whereas 1-Ce does not, although 3 and 4 form H-bonded adducts. Complexes 1-Y and 1-Sc form adducts with CpH without cleaving the acidic C–H bond, 1-Ce cleaves the Cp–H bond, but 2 reacts to form the very rare H+–[C5H5]−–H+ motif. Complex 1-Ce cleaves alkyne C–H bonds but the products rearrange upon formation, while complex 1-Y cleaves the C–H bond in diphenylacetone forming a product which rearranges to the Y–O bonded enolate product

Nutritional genomics and alzheimer’s disease

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Obesity and overweight frequency in school-children from an urban area from Merida-Venezuela

Objetivos. Determinar la frecuencia de alteraciones en el peso en escolares de 3 planteles públicos, ubicados en la zona urbana de la ciudad de Mérida-Venezuela. Métodos. Estudio observacional, transversal, en el cual se incluyeron 349 escolares, con edades entre 6 y 13 años, 189 de sexo femenino y 160 de sexo masculino, provenientes de 3 planteles públicos, ubicados en la Urb. J.J. Osuna Rodríguez y la Parroquia, de la Ciudad de Mérida; 127 niños del plantel A (Los Curos), 111 del B (Bicentenario) y 111 del C (10 de Diciembre). A los niños se les determinó el peso y la talla y se calculó el índice de masa corporal (IMC) y el indicador talla edad (T/E). Según el IMC, se ubicó cada niño en el percentil correspondiente para sexo y edad; se clasificaron en: obesos: IMC > percentil 97th, sobrepeso: IMC <97th y > 90th, normopeso: IMC< 90th y >10th y bajo peso: IMC < 10th. El diagnostico nutricional antropométrico se hizo por combinación de los indicadores IMC y T/E. Resultados. El 35% del total de niños presentó alteraciones del IMC para su edad; el sobrepeso representó el 11%, la obesidad el 14% y el bajo peso el 10% del total. En cada plantel no se observó la misma distribución. La frecuencia de alteraciones en el IMC fue significativamente menor (p<0,01) en las niñas (26%) que en los varones (42%). Esta diferencia se correspondió con un aumento significativo en la frecuencia de obesidad y sobrepeso en los varones. En el 26,4% hubo alteraciones en la talla-edad, siendo mas frecuentes en los varones que en las niñas. Los niños con obesidad y sobrepeso presentaron una mayor frecuencia de talla alta (p<0,05) que los normales. En base al diagnostico nutricional antropométrico el 8,8% de los niños presentaron peso y talla bajos. Conclusiones. Las cifras obtenidas documentan un importante aumento en la frecuencia de obesidad y sobrepeso en nuestros escolares. Las potenciales consecuencias en términos de morbilidad y mortalidad nos obligan a mejorar las estrategias en prevención primaria y secundaria, no solo promoviendo el ejercicio y optimizando la alimentación de nuestros niños, sino además, identificando a los grupos de riesgo.16-21Objective. To assess the frequency of weight problems in school-children from educational centers of Mérida-Venezuela. Methods. An observational and transversal study was performed. Three hundred forty nine school-children, 6 to 12 years old, 160 boys and 189 girls, were studied. They belong to three educational centers from Mérida; 127 children from the school A (Los Curos), 111 from the school B (Bicentenario), and 111 from the school C (10 de Diciembre). The weight and stature were measured in all children. Body mass index-for age (BMI/A) and stature-for age (S/A) were established: obese (BMI ≥ 97thpercentile), overweight (BMI <97th and > 90th), normal weight (BMI ≤ 90th and ≥10th), and low weight (BMI< 10th). The nutritional evaluation was done by the combination of 2 indexes: BMI-for age (BMI/A) and stature-for age (S/A). Results. BMI-for age abnormal values were obtained in 35% of the 349 school-children; overweight was diagnosed in 11% of them, 14% were obese and low weight was found in 10% of the sample. There was a significative difference in the BMI/A related to the sex: alterations were observed in the 26% of girls and 42% of boys (p<0,01). The difference was attributed to a higher frequency of obesity and overweight in boys. The overall frequency of alterations in the S/A index was 26.4%, and it was more frequent in boys than in girls. The school-children with obesity and overweight showed a higher frequency of high stature compared to normal weight subjects (p<0,05). According to the nutrition evaluation, 8.8% of these school-children showed low weight and height. Conclusion. Our results reveal a substantial increase in frequency of obesity and overweight in children from educational centers in Mérida city-Venezuela. The potential consequences in terms of morbidity and mortality, should be taking in consideration in order to develop secure and preventive strategies. Individuals at risk should be identified. Promoting regular physical activities in childhood and improving the quality of nutrition, are priorities to overcome these problems

Tenth aniversary of the venezuelan journal of endocrinology and metabolism

[email protected]@intercable.net.veCuatrimestra