Excess nitrogen responsive HvMADS27 transcription factor controls barley root architecture by regulating abscisic acid level.

Nitrogen (N) is an important element for plant growth and development. Although several studies have examined plants' response to N deficiency, studies on plants' response to excess N, which is common in fertilizer-based agrosystems, are limited. Therefore, the aim of this study was to examine the response of barley to excess N conditions, specifically the root response. Additionally, genomic mechanism of excess N response in barley was elucidated using transcriptomic technologies. The results of the study showed that barley MADS27 transcription factor was mainly expressed in the roots and its gene contained N-responsive cis-regulatory elements in the promoter region. Additionally, there was a significant decrease in HvMADS27 expression under excess N condition; however, its expression was not significantly affected under low N condition. Phenotypic analysis of the root system of HvMADS27 knockdown and overexpressing barley plants revealed that HvMADS27 regulates barley root architecture under excess N stress. Further analysis of wild-type (WT) and transgenic barley plants (hvmads27 kd and hvmads27 c-Myc OE) revealed that HvMADS27 regulates the expression of HvBG1 ß-glucosidase, which in turn regulates abscisic acid (ABA) level in roots. Overall, the findings of this study showed that HvMADS27 expression is downregulated in barley roots under excess N stress, which induces HvBG1 expression, leading to the release of ABA from ABA-glucose conjugate, and consequent shortening of the roots.

Barley microRNAs as metabolic sensors for soil nitrogen availability.

Barley (Hordeum vulgare) is one of the most important crops in the world, ranking 4th in the worldwide production. Crop breeders are facing increasing environmental obstacles in the field, such as drought, salinity but also toxic over fertilization which not only impacts quality of the grain but also an yield. One of the most prevalent mechanisms of gene expression regulation in plants is microRNA-mediated silencing of target genes. We identified 13 barley microRNAs and 2 microRNAs* that are nitrogen excess responsive. Four microRNAs respond only in root, eight microRNAs only in shoot and one displays broad response in roots and shoots. We demonstrate that 2 microRNAs* are induced in barley shoot by nitrogen excess. For all microRNAs we identified putative target genes and confirmed microRNA-guided cleavage sites for ten out of thirteen mRNAs. None of the identified microRNAs or their target genes is known as nitrogen excess responsive. Analysis of expression pattern of thirteen target mRNAs and their cognate microRNAs showed expected correlations of their levels. The plant microRNAs analyzed are also known to respond to nitrogen deprivation and exhibit the opposite expression pattern when nitrogen excess/deficiency conditions are compared. Thus, they can be regarded as metabolic sensors of the regulation of nitrogen homeostasis in plants.

Safety of the application of nanosilver and nanogold in topical cosmetic preparations.

The safety of the use of cosmetic preparations with silver or gold nanoparticles was assessed. This study describes the methodology and results of research involving the generation of suspensions of silver and gold nanoparticles and creams with added silver or gold at concentrations of 20, 65, 110, 155, and 200 mg/kg. The silver nanoparticles ranged from 8 to 140 nm, and the gold nanoparticles, measured 13-99 nm. The sizes were determined using dynamic light scattering. The presence of metallic nanoparticles in the obtained oil-in-water emulsions was confirmed with UV-vis spectroscopy and transmission electron microscopy with an X-ray scattering spectrometer (TEM-EDX). Additionally, based on the TEM-EDX results, it was possible to analyse the distributions of the silver nanoparticles in the tested cosmetic emulsions. Microbiological tests showed that both the silver and gold nanoparticle emulsion possessed satisfactory fungicidal properties. Based on viscosity curves, the lowest estimated yield limits were achieved by the reference cream and the creams with the gold and silver nanoparticles at concentrations of 20 and 65 mg/kg, respectively, which improved their consistencies and distributions on the skin. The best appraisals from the respondents in terms of consistency, absorption, oiling, colour, and smell were received for the emulsion containing 200 mg/kg gold nanoparticles. The worst assessment in terms of uniformity, colour, and smell were obtained for the emulsion with 200 mg/kg silver nanoparticles. However, the most important aspect of this study was the assessment of the permeabilities of the metallic nanoparticles through imitation skin in the form of dermal membranes. The highest permeabilities were confirmed for the creams with metallic nanoparticles present at 110--200 mg/kg. This permeability is an issue of concern given the toxic properties of metallic nanoparticles for living organisms.

Barley primary microRNA expression pattern is affected by soil water availability.

MicroRNAs are short molecules of 21-24 nt in length. They are present in all eukaryotic organisms and regulate gene expression by guiding posttranscriptional silencing of mRNAs. In plants, they are key players in signal transduction, growth and development, and in response to abiotic and biotic stresses. Barley (Hordeum vulgare) is an economically important monocotyledonous crop plant. Drought is the world's main cause of loss in cereal production. We have constructed a high-throughput Real-Time RT-qPCR platform for parallel determination of 159 barley primary microRNAs' levels. The platform was tested for two drought-and-rehydration-treated barley genotypes (Rolap and Sebastian). We have determined changes in the expression of primary microRNAs responding to mild drought, severe drought, and rehydration. Based on the results obtained, we conclude that alteration in the primary microRNA expression is relative to the stress's intensity. Mild drought and rehydration mostly decrease the pri-miRNA levels in both of the tested genotypes. Severe drought mainly induces the primary microRNA expression. The main difference between the genotypes tested was a much-stronger induction of pri-miRNAs in Rolap encountering severe drought. The primary microRNAs respond dynamically to mild drought, severe drought, and rehydration treatments. We propose that some of the individual pri-miRNAs could be used as drought stress or rehydration markers. The usage of the platform in biotechnology is also postulated.

Negative correlation between cerebrospinal fluid tau protein and cognitive functioning in children with acute lymphoblastic leukemia.

The aim of the study was to assess whether cerebrospinal fluid tau protein is associated with cognitive changes in children with acute lymphoblastic leukemia (ALL). Examination of 38 ALL patients revealed a statistically significant increase in tau protein on treatment day 59 and at two points during consolidation phase. Cognitive functioning was examined in 19 patients at an average of 3.7 years after diagnosis. The level of tau at the initiation of maintenance therapy was negatively correlated with verbal abilities measured on an intellectual scale. The study suggests that standard ALL treatment may cause a decline in cognitive functioning.