Auxins, auxin transport inhibitors, and competitors for auxin receptors do not show statistically significant differences in 212 molecular descriptors

[EN] This study compares 212 molecular descriptors of four auxins (indolebutyric acid; indoleacetic acid; 2,4-dichlorophenoxyacetic acid; 1-naphthaleneacetic acid), three auxin transport inhibitors [2-(naphthalen-1-ylcarbamoyl)benzoic acid; 2,3,5-triiodobenzoic acid; 9-hydroxy-9H-fluorene-9-carboxylic acid], and five competitors for auxin receptors [2-(2,4,6-trichlorophenoxy)acetic acid; 2-(4-chlorophenoxy)-2-methylpropanoic acid; 3-phenylpropanoic acid; 3-(2-chlorophenoxy)butanoic acid; 2-amino-3-(5-methyl-1H-indol-3yl) propanoic acid]. The analysed compounds did not show statistically significant differences in any of those descriptors, suggesting that chemical and structural differences, per se, do not determine their functional diversities. We propose that combination with other, yet unknown chemical groups confers the specificity necessary for these molecules to act as auxins, as auxin transport inhibitors or auxin receptor competitors.This research was supported by the Bioplant Centre (University of Ciego de Avila, Cuba) and the Universitat Politecnica de Valencia (Spain).Andújar, I.; Gómez, D.; Pérez, L.; Vicente, O.; Lorenzo, JC. (2019). Auxins, auxin transport inhibitors, and competitors for auxin receptors do not show statistically significant differences in 212 molecular descriptors. Romanian Biotechnological Letters. 24(3):407-411. https://doi.org/10.25083/rbl/24.3/407.411S40741124

Histology of maize seeds and young germinating embryos after liquid nitrogen exposure

[EN] Maize represents a staple food crop and is the second most important agricultural commodity globally. Considering the important role of maize for food security, the long-term conservation of valuable germplasm is critical to ensure that high levels of genetic diversity are available for breeding superior cultivars to face future challenges. Cryopreservation is regarded as the most appropriate tool for long-term germplasm preservation and has been investigated in different crops. This short communication adds to the existing knowledge on maize cryopreservation by describing histological changes observed in maize seeds and young germinating embryos after liquid nitrogen (LN) exposure. Plants were examined immediately after recovery from LN (day zero) and following 3 days of germination. At day 3, seeds exposed to LN showed lower germination rates than non-cryostored seeds, i.e., 60.7% vs. 83.3%. Histological evaluation at day 3 revealed that the thickness of the conical endosperm and the scutellum did not show any statistically significant differences between control and cryopreserved seeds. In contrast, for the other histological evaluations made, mostly regarding the thickness of mesocarp, mealy endosperm, plumule, radicle and the epidermis, significant differences were observed between control and cryostored seeds with the former consistently displaying higher average values than the latter.Villalobos-Olivera, A.; Pereira, R.; Gómez, D.; Martínez, J.; Escalante, D.; Martínez-Montero, ME.; Hajari, E.... (2021). Histology of maize seeds and young germinating embryos after liquid nitrogen exposure. Romanian Biotechnological Letters. 26(4):2855-2861. https://doi.org/10.25083/rbl/26.4/2855.28612855286126

Mutagenic effects of sodium azide on pineapple micropropagant growth and biochemical profile within temporary immersion bioreactors

Sodium azide (NaN3) is widely used to induce mutagenesis within in vitro plant systems. However, since this mutagenesis is undirected, its unintended effects demand characterization. This study investigated the mutagenic effects of sodium azide (0-0.45 mM) on selected growth (shoot multiplication rate and shoot cluster fresh weight) and biochemical (aldehydes, chlorophylls, carotenoids and phenolics) parameters in pineapple micropropagants within temporary immersion bioreactors (TIBs). The content of soluble phenolics in the culture medium was also evaluated. Irrespective of the concentration NaN3 decreased shoot multiplication rate (by 87% relative to the control at 0.45 mM) and fresh weight (by 66% relative to the control at 0.45 mM). Levels of chlorophyll a and b, and soluble phenolics in the culture medium were also negatively correlated with NaN3 concentration. Interestingly, NaN3 application increased shoot carotenoid and soluble phenolic levels but had no significant effect on a range of established plant stress biomarkers: cell wall-linked phenolic levels, malondialdehyde and other aldehydes. Given that 0.19 mM NaN3 decreased shoot multiplication rate by 50% and resulted in propagants that displayed no morphologically abnormalities, increased levels of photoprotective pigments (relative to the control) and no significant increase in lipid peroxidation products, the mutagen can be used at this concentration to induce pineapple mutagenesis in TIB based studies aimed at producing agriculturally-useful mutants

Salinity induces specific metabolic changes in sugarcane shoot explants in temporary immersion bioreactors

There is a great demand of salt-tolerant sugarcane planting material in Cuba. Temporary immersion bioreactors (TIB) are effective to significantly increase sugarcane in vitro shoot proliferation rate from 1:4 in conventional containers to about 1:35. Sugarcane micropropagation in TIBs under NaCl stress may help screen mutants with salinity tolerance. We developed the experiment shown here to identify a NaCl concentration able to stress shoot in TIBs. At 30 days of culture initiation with different NaCl levels (0 - 200 mM), explant multiplication rate, shoot cluster fresh mass, and levels of aldehydes, chlorophylls, carotenoids and phenolics were determined in the plant material. Content of soluble phenolics in the culture medium was also evaluated. Addition of NaCl decreased shoot multiplication rate and fresh mass. Other statistically significant differences were recorded but the most important were noted in the increased contents of carotenoids, malondialdehyde, other aldehydes and soluble phenolics in the plants, and in the soluble phenolics in the culture medium. This research may be useful for future experiments of in vitro selection of new sugarcane genetic materials with NaCl tolerance. Fifty percent of multiplication rate was reduced with 89 mM NaCl which can be used to stress shoots during micropropagation in TIBs and eventually detect mutants with salt tolerance

Estudio de la factibilidad para la creación de la especialidad Odontológica en Medicina Bucal y periodoncia, medicina bucal y cirugía. Facultad de Odontología de la UNAN-León. Año 2021

Tesis (Dr. Cirujano Dentista)-Universidad Nacional Autónoma de Nicaragua, LeónUNAN-Leó

Elucidating the promotional effect of ultra-low Zn content on Cu for CO2 hydrogenation to methanol

CO hydrogenation to methanol is currently of great importance for energy and environmental objectives. Herein, the effect of ultra-low amounts of Zn on Cu/SiO catalysts for CO hydrogenation was studied, maintaining the average Cu particle size in the 2–4 nm range to minimize structure sensitivity effects. The addition of Zn amounts as low as Zn/Cu = 0.01 increases the methanol formation rate up to twelve times compared to Cu/SiO catalyst, highlighting the importance of isolated Zn atoms in methanol synthesis catalysis. At these very low Zn contents, CuZn alloy sites are identified, with strong affinity for CO adsorption. When Zn content is increased, CuZn alloy disappears to give rise to mostly metallic Cu likely forming Cu-ZnO interfacial sites. Steady state and transient Operando-DRIFTS evidence that the reaction pathways depend on the nature of the active sites with reverse water–gas shift and CO hydrogenation dominant for low Zn content catalysts and formate pathway for high Zn content catalysts.The authors thank the government of Chile for the financing assigned through the following project: National Agency for Research and Development (ANID) FONDECYT grant 1190178, CONICYT PIA/APOYO CCTE AFB170007. D.G. thanks ANID-Chile, Beca de Doc.Nac./2019-21190800 and the Project UCO 1866 of the Universidad de Concepcion

Reductive amination of phenol over Pd-based catalysts: elucidating the role of the support and metal nanoparticle size

Funding Information: The authors would like to thank FONDECYT Grant 1190063, ACE Grant 210012, 2260311 AD/EQ and FONDEQUIP EQM Grant170077 for their financial support. Publisher Copyright: © 2022 The Royal Society of Chemistry.The heterogeneously catalyzed reductive amination of phenolics from lignin is considered an attractive sustainable route for the synthesis of primary or high-order aromatic and aliphatic amines. Here, the reductive amination of phenol with cyclohexylamine was studied, and insights into the role of the catalyst support, metal nanoparticle sizes, and acidic properties were provided. Bulk and surface characterization, IR experiments, and kinetic measurements were performed, and their results were correlated with the catalytic performance and the content of Lewis acid sites (Pd/Al2O3 > Pd/C > Pd/SiO2). The Lewis acid sites in the support and those formed by H2 spillover assisted phenol hydrogenation and C=N bond activation, enhancing the formation of secondary amines (selectivity >90%). The Pd coordination in the particles strongly affected the catalytic activity, indicating that phenol amination is a structure-sensitive reaction. The turnover frequency vs. dispersion profiles combined with the site distributionsin the Pd particles (edge, corner, and terraces) indicate that low-coordination sites favor phenol amination, which was confirmed via diffuse reflectance infrared spectroscopy with Fourier transform and high-resolution transmission electron microscopy. This study could contribute to the upcycling of fresh and recycled lignin fractions to produce aromatic and aliphatic amines.Peer reviewe

Techno-Economic and Environmental Assessment of Municipal Solid Waste Energetic Valorization

In 2019, Chile generated 20 million tons of waste, 79% of which was not properly disposed of, thereby providing an attractive opportunity for energy generation in advanced thermochemical conversion processes. This study presents a techno-economic and environmental assessment of the implementation of Waste-Integrated Gasifier-Gas Turbine Combined Cycle (WIG-GTCC) technology as an alternative for Municipal Solid Waste (MSW) treatment. The studied case assesses the conversion of 14.61 t·h−1 of MSW, which produces a combustible gas with a flow rate of 34.2 t·h−1 and LHV of 5900 kJ·kg−1, which, in turn, is used in a combined cycle to generate 19.58 MW of electrical power. The proposed economic assessment of the technology uses the energy generation processes as a reference, followed by a model for an overall economic evaluation. The results have shown that the profit could be up to USD 24.1 million, and the recovery of investment between 12 and 17 years would improve the environmental impacts of the current disposal technology. The WIG-GTCC has the most efficient conversion route, emitting 0.285 kg CO2eq/kWh, which represents 48.21% of the potential yield of global warming over 100 years (GWP100) of incineration and 58.51% of the GWP100 of the standard gasification method. The WIG-GTCC would enable the energetic valorization of MSW in Chile, eliminate problems associated with landfill disposal, and increase opportunities for decentralized electricity generation