Pseudomonas guineae sp.nov, a novel psychrotolerant bacterium from an Antarctic environment

Two Gram-negative, cold-adapted, aerobic bacteria, designated strains M8T and M6, were isolated from soil collected from the South Shetland Islands. The organisms were rod-shaped, catalase- and oxidase-positive and motile by means of polar flagella. These two psychrotolerant strains grew between −4 and 30 °C. 16S rRNA gene sequence analysis placed strains M8T and M6 within the genus Pseudomonas. DNA–DNA hybridization experiments between the Antarctic isolate M8T and type strains of phylogenetically related species, namely Pseudomonas peli and Pseudomonas anguilliseptica, revealed levels of relatedness of 33 and 37 %, respectively. Strain M6 showed 99 % DNA similarity to strain M8T. Several phenotypic characteristics, together with data on cellular fatty acid composition, served to differentiate strains M8T and M6 from related pseudomonads. On the basis of the polyphasic taxonomic evidence presented in this study, it can be concluded that strains M8T and M6 belong to the same genospecies, representing a novel species of the genus Pseudomonas, for which the name Pseudomonas guineae sp. nov. is proposed. The type strain is M8T (=LMG 24016T=CECT 7231T)

Evaluation of a crop rotation with biological inhibition potential to avoid N2O emissions in comparison with synthetic nitrification inhibition

Agriculture has increased the release of reactive nitrogen to the environment due to crops' low nitrogen-use efficiency (NUE) after the application of nitrogen-fertilisers. Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) have been adopted to reduce nitrogen losses. Otherwise, cover crops can be used in crop-rotation-strategies to reduce soil nitrogen pollution and benefit the following culture. Sorghum (Sorghum bicolor) could be a good candidate as it is drought tolerant and its culture can reduce nitrogen losses derived from nitrification because it exudates biological nitrification inhibitors (BNIs). This work aimed to evaluate the effect of fallow-wheat and sorghum cover crop-wheat rotations on N2O emissions and the grain yield of winter wheat crop. In addition, the suitability of DMPP addition was also analyzed. The use of sorghum as a cover crop might not be a suitable option to mitigate nitrogen losses in the subsequent crop. Although sorghum–wheat rotation was able to reduce 22% the abundance of amoA, it presented an increment of 77% in cumulative N2O emissions compared to fallow–wheat rotation, which was probably related to a greater abundance of heterotrophic-denitrification genes. On the other hand, the application of DMPP avoided the growth of ammonia-oxidizing bacteria and maintained the N2O emissions at the levels of unfertilized-soils in both rotations. As a conclusion, the use of DMPP would be recommendable regardless of the rotation since it maintains NH4+ in the soil for longer and mitigates the impact of the crop residues on nitrogen soil dynamics.This work was supported by the Spanish Government (RTI2018-094623-B-C21 and C22 MCIU/AEI/FEDER, UE) and the Basque Government (IT-932-16). Dr. Adrián Bozal-Leorri held a grant from the Basque Government (PRE-2020-2-0142). Dr. Mario Corrochano-Monsalve held a grant from the Ministry of Economy and Business of the Spanish Government (BES-2016-076725)

Covalent grafting of molecular catalysts on C₄NₓH_{y} as robust, efficient and well-defined photocatalysts for solar fuel synthesis

The covalent attachment of molecules to 2D materials is an emerging area as strong covalent chemistry offers new hybrid properties and greater mechanical stability compared with nanoparticles. A nickel bis-aminothiophenol catalyst was grafted onto a range of 2D carbon nitrides C₄NₓH_{y} to form noble metal-free photocatalysts for H2 production. The hybrids produce H_{2} beyond 8 days with turnover numbers reaching 1360 based on nickel, a more than 3 fold higher durability than reported molecular catalyst-carbon nitride mixtures, and under longer wavelengths (>475 nm). Time-resolved spectroscopy reveals sub-microsecond electron transfer to the grafted catalyst, six orders of magnitude faster compared with similar reports of non-grafted catalysts. The photoelectrons on the catalyst have a ca. 1000 times longer half-time (7 ms) compared with bare carbon nitride (10 μs). The grafting strategy operates across a range of molecular catalyst-carbon nitride combinations, thus paving the way for robust efficient photocatalysts based on low-cost tunable components

New forms of social interaction: virtual communication and health

It is examined if the relationship empirically demonstrated between health and face-to-face social interactions is confirmed when it is virtual. The objective is to know if the perception of psychological well-being and receiving social support would explain the frequency of participation in virtual social networks (VSN). An ex-post-facto design was applied to a sample of 510 university Internet users (age, M = 22.89, SD = 5.67, 78.9% women). The level of psychological well-being (Spanish adaptation of the Ryff Psychological Well-Being Scale), social support (Family Social Support and Friends questionnaire - AFA) and the frequency of use of VSN are evaluated. To determine the relationships between the variables, correlation and hierarchical regression analyzes were carried out. The relative contribution of the perception of psychological well-being and of obtaining social support in the frequency of VSN use is confirmed, controlling the influences of age and gender. Specifically, the perception of having less ability to dominate the social environment and to obtain social support for friendships through VSN explains and allows predicting the increase in the frequency of use of such networks.Se examina si la relación demostrada empíricamente entre salud e interacciones sociales presenciales se confirma cuando ésta es virtual. El objetivo es conocer si la percepción de bienestar psicológico y de recibir apoyo social explicaría la frecuencia de participación en redes sociales virtuales (RSV). Se aplica un diseño ex-post-facto sobre una muestra de 510 internautas universitarios (edad; M =22,89; DT= 5,67; 78,9% mujeres). Se evalúa el nivel de bienestar psicológico (adaptación española de la Escala de Bienestar Psicológico de Ryff), de apoyo social (cuestionario Apoyo Social Familiar y Amigos - AFA) y la frecuencia de uso de las RSV. Para determinar las relaciones entre las variables se realizaron análisis de correlación y de regresión jerárquica Se confirma la contribución relativa de la percepción de bienestar psicológico y de obtención de apoyo social en la frecuencia de uso de RSV, controlando las influencias de la edad y el género. Concretamente, la percepción de poseer menor capacidad de dominar el ambiente social y la de obtener apoyo social por las amistades a través de las RSV, explica y permite predecir el incremento en la frecuencia de uso de dichas redes

Biological and synthetic approaches to inhibiting nitrification in non‑tilled Mediterranean soils

[EN] Background: The increasing demand for food production has led to a tenfold increase in nitrogen (N) fertilizer use since the Green Revolution. Nowadays, agricultural soils have been turned into high-nitrifying environments that increase N pollution. To decrease N losses, synthetic nitrification inhibitors (SNIs) such as 3,4-dimethylpyrazole phosphate (DMPP) have been developed. However, SNIs are not widely adopted by farmers due to their biologically limited stability and soil mobility. On the other hand, allelopathic substances from root exudates from crops such as sorghum are known for their activity as biological nitrification inhibitors (BNIs). These substances are released directly into the rhizosphere. Nevertheless, BNI exudation could be modified or even suppressed if crop development is affected. In this work, we compare the performance of biological (sorghum crop) and synthetic (DMPP) nitrification inhibitors in field conditions. Results: Sorghum crop BNIs and DMPP prevented an increase in the abundance of ammonia-oxidizing bacteria (AOB) without affecting the total bacterial abundance. Both nitrification inhibitors maintained similar soil NH4+ content, but at 30 days post-fertilization (DPF), the sorghumBNIs resulted in higher soil NO3- content than DMPP. Even so, these inhibitors managed to reduce 64% and 96%, respectively, of the NO3--N/NH4+-N ratio compared to the control treatment. Similar to soil mineral N, there were no differences in leaf delta N-15 values between the two nitrification inhibitors, yet at 30 DPF, delta N-15 values from sorghum BNI were more positive than those of DMPP. N2O emissions from DMPP-treated soil were low throughout the experiment. Nevertheless, while sorghum BNIs also maintained low N2O emissions, they were associated with a substantial N2O emission peak at 3 DPF that lasted until 7 DPF. Conclusions: Our results indicate that while sorghum root exudates can reduce nitrification in field soil, even at the same efficiency as DMPP for a certain amount of time, they are not able to prevent the N pollution derived from N fertilization as DMPP does during the entire experiment. Graphic AbstractThis project was funded by the Spanish Government (RTI2018-094623-B-C22 MCIU/AEI/FEDER, UE) and by the Basque Government (IT-932-16). Adrian Bozal-Leorri holds a Grant from the Basque Government (PRE-2020-2-0142). Mario Corrochano-Monsalve holds a Grant from the Ministry of Economy and Business of the Spanish Government (BES-2016-076725)

Evidences towards deciphering the mode of action of dimethylpyrazole-based nitrification inhibitors in soil and pure cultures of Nitrosomonas europaea

Background: Agriculture relies on the intensive use of synthetic nitrogen (N) fertilizers to maximize crop yields, which has led to the transformation of agricultural soils into high-nitrifying environments. Nevertheless, nitrification inhibitors (Nis) have been developed to suppress soil-nitrifier activity and decrease N losses. The Nis 3,4-dimethylpyrazole phosphate (DMPP) and 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA) are able to reduce N2O emissions and maintain soil NH4+ for a longer time. Although both Nls have been proven to be effective to inhibit soil nitrification, their exact mode of action has not been confirmed. We aimed to provide novel insights to further understand the mode of action of DMP-based Nis. We evaluated the performance of DMPP and DMPSA in soil and pure cultures of nitrifying bacteria Nitrosomonas europaea. Results: DMPSA did not inhibit nitrification in pure cultures of N. europaea. In the soil, we evidenced that DMPSA needs to be broken into DMP to achieve the inhibition of nitrification, which is mediated by a soil biological process that remains to be identified. Moreover, both DMPP and DMPSA are thought to inhibit nitrification due to their ability to chelate the Cu2+ cations that the ammonia monooxygenase enzyme (AMO) needs to carry on the first step of NH4+ oxidation. However, the efficiency of DMPP was not altered regardless the Cu2+ concentration in the medium. In addition, we also showed that DMPP targets AMO but not hydroxylamine oxidoreductase enzyme (HAO). Conclusions: The inability of DMPSA to inhibit nitrification in pure cultures together with the high efficiency of DMPP to inhibit nitrification even in presence of toxic Cu2+ concentration in the medium, suggest that the mode of action of DMP-based Nis does not rely on their capacity as metal chelators.This project was funded by the Spanish Government (RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE), by the Basque Government (IT-932-16), and by EuroChem Agro Iberia S.L.U. Dr. Adrian Bozal-Leorri held a grant from the Basque Government (PRE-2020-2-0142)

Ejercicio físico y calidad de vida en estudiantes universitarios

The recommendation of physical exercise as a strategy for prevention and promotion of health has been established in both the health and psychological areas. Despite the increased flow of research in recent years, the need to increase the empirical support of the relationships between physical activity and quality of life is well known. In favor of this need, this study aims to: 1. Clarify if there are different typologies between those who perform physical exercise and those who do not. 2. Delimit more specific typologies according to the frequency of realization from a gender perspective. To do this, a battery of questionnaires focused on quality of life indicators: depression, state anxiety (A-State), trait anxiety (A-Trait), personal satisfaction and satisfaction with life were administered to a sample of 153 university students. By means of the biphasic cluster analysis, we obtain 2 typologies among the students that perform some physical activity and those students who do not perform any physical exercise, the first responding to a better score in the previously mentioned indicators. Deepening the frequency, and taking into account the gender of individuals who exercise; we have differentiated 4 typologies, 2 composed mainly by men who behave as expected, responding to a better quality of life the category that performs a higher frequency of exercise a week; and 2 others composed of women who present differences that are not defined so pronounced and some variables are not related according to expectations. This fact underscores the need for more thorough investigation. We encourage research to develop physical activity programs aimed at improving the quality of life in different populations.La recomendación del ejercicio físico como estrategia de prevención y promoción de la salud se ha establecido tanto en el ámbito sanitario como en el psicológico. A pesar del aumento del flujo de investigación en los últimos años, se es consciente de la necesidad de incrementar el respaldo empírico de las relaciones entre la actividad física y la calidad de vida. En favor de esta necesidad, este estudio se plantea como objetivos: 1. Clarificar si existen diferentes tipologías entre quienes realizan ejercicio físico y los que no. 2. Delimitar tipologías más específicas atendiendo a la frecuencia de realización desde una perspectiva de género. Para ello, se administró una batería de cuestionarios centrados los indicadores de calidad de vida: depresión, ansiedad estado, ansiedad rasgo, satisfacción personal y satisfacción con la vida a una muestra de 153 estudiantes universitarios. Mediante el análisis clúster biétapico, obtenemos 2 conglomerados entre los estudiantes que realizan alguna actividad física y aquellos estudiantes que no realizan ningún ejercicio físico, respondiendo los primeros a unas mejores puntuaciones en los indicadores anteriormente nombrados. Profundizando en la frecuencia, y teniendo en cuenta el género de los individuos que practican ejercicio, hemos diferenciado 4 conglomerados, 2 compuestos principalmente por hombres que se comportan como cabría esperar, respondiendo a una mejor calidad de vida el conglomerado que realiza una mayor frecuencia de ejercicio a la semana; y otras 2 compuestos por mujeres las cuales presentan diferencias que no se definen de forma tan pronunciada y algunas variables no se relacionan conforme a las expectativas. Este hecho remarca la necesidad de una investigación más exhaustiva. Animamos la labor de investigación en busca de elaborar programas de actividad física orientados a mejorar la calidad de vida en las distintas poblaciones

Biological nitrification inhibitor-trait enhances nitrogen uptake by suppressing nitrifier activity and improves ammonium assimilation in two elite wheat varieties

Synthetic nitrification inhibitors (SNI) and biological nitrification inhibitors (BNI) are promising tools to limit nitrogen (N) pollution derived from agriculture. Modern wheat cultivars lack sufficient capacity to exude BNIs, but, fortunately, the chromosome region (Lr#n-SA) controlling BNI production in Leymus racemosus, a wild relative of wheat, was introduced into two elite wheat cultivars, ROELFS and MUNAL. Using BNI-isogenic-lines could become a cost-effective, farmer-friendly, and globally scalable technology that incentivizes more sustainable and environmentally friendly agronomic practices. We studied how BNI-trait improves N-uptake, and N-use, both with ammonium and nitrate fertilization, analysing representative indicators of soil nitrification inhibition, and plant metabolism. Synthesizing BNI molecules did not mean a metabolic cost since Control and BNI-isogenic-lines from ROELFS and MUNAL presented similar agronomic performance and plant development. In the soil, ROELFS-BNI and MUNAL-BNI plants decreased ammonia-oxidizing bacteria (AOB) abundance by 60% and 45% respectively, delaying ammonium oxidation without reducing the total abundance of bacteria or archaea. Interestingly, BNI-trait presented a synergistic effect with SNIs since made it also possible to decrease the AOA abundance. ROELFS-BNI and MUNAL-BNI plants showed a reduced leaf nitrate reductase (NR) activity as a consequence of lower soil NO3- formation and a higher amino acid content compared to BNI-trait lacking lines, indicating that the transfer of Lr#-SA was able to induce a higher capacity to assimilate ammonium. Moreover, the impact of the BNI-trait in wheat cultivars was also noticeable for nitrate fertilization, with improved N absorption, and therefore, reducing soil nitrate content.This project was funded by the Spanish Government (RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE) and by the Basque Government (IT932-16; IT1560-22; 00048-ID2021-45). AB-L and LU held grants from the Basque Government (PRE-2020-2-0142 and PRE-2020-1-0127)