Multiple Facets of Nitrogen: From Atmospheric Gas to Indispensable Agricultural Input.

Nitrogen (N) is a gas and the fifth most abundant element naturally found in the atmosphere. N's role in agriculture and plant metabolism has been widely investigated for decades, and extensive information regarding this subject is available. However, the advent of sequencing technology and the advances in plant biotechnology, coupled with the growing interest in functional genomics-related studies and the various environmental challenges, have paved novel paths to rediscovering the fundamentals of N and its dynamics in physiological and biological processes, as well as biochemical reactions under both normal and stress conditions. This work provides a comprehensive review on multiple facets of N and N-containing compounds in plants disseminated in the literature to better appreciate N in its multiple dimensions. Here, some of the ancient but fundamental aspects of N are revived and the advances in our understanding of N in the metabolism of plants is portrayed. It is established that N is indispensable for achieving high plant productivity and fitness. However, the use of N-rich fertilizers in relatively higher amounts negatively affects the environment. Therefore, a paradigm shift is important to shape to the future use of N-rich fertilizers in crop production and their contribution to the current global greenhouse gases (GHGs) budget would help tackle current global environmental challenges toward a sustainable agriculture.

Novel QTL Associated with Aerenchyma-Mediated Radial Oxygen Loss (ROL) in Rice (Oryza sativa L.) under Iron (II) Sulfide.

In rice, high radial oxygen loss (ROL) has been associated with the reduction in the activity of methanogens, therefore reducing the formation of methane (CH4) due to the abundance in application of nitrogen (N)-rich fertilizers. In this study, we evaluated the root growth behavior and ROL rate of a doubled haploid (DH) population (n = 117) and parental lines 93-11 (P1, indica) and Milyang352 (P2, japonica) in response to iron (II) sulfide (FeS). In addition, we performed a linkage mapping and quantitative trait locus (QTL) analysis on the same population for the target traits. The results of the phenotypic evaluation revealed that parental lines had distinctive root growth and ROL patterns, with 93-11 (indica) and Milyang352 (japonica) showing low and high ROL rates, respectively. This was also reflected in their derived population, indicating that 93.2% of the DH lines exhibited a high ROL rate and about 6.8% had a low ROL pattern. Furthermore, the QTL and linkage map analysis detected two QTLs associated with the control of ROL and root area on chromosomes 2 (qROL-2-1, 127 cM, logarithm of the odds (LOD) 3.04, phenotypic variation explained (PVE) 11.61%) and 8 (qRA-8-1, 97 cM, LOD 4.394, PVE 15.95%), respectively. The positive additive effect (2.532) of qROL-2-1 indicates that the allele from 93-11 contributed to the observed phenotypic variation for ROL. The breakthrough is that the qROL-2-1 harbors genes proposed to be involved in stress signaling, defense response mechanisms, and transcriptional regulation, among others. The qPCR results revealed that the majority of genes harbored by the qROL-2-1 recorded a higher transcript accumulation level in Milyang352 over time compared to 93-11. Another set of genes exhibited a high transcript abundance in P1 compared to P2, while a few were differentially regulated between both parents. Therefore, OsTCP7 and OsMYB21, OsARF8 genes encoding transcription factors (TFs), coupled with OsTRX, OsWBC8, and OsLRR2 are suggested to play important roles in the positive regulation of ROL in rice. However, the recorded differential expression of OsDEF7 and OsEXPA, and the decrease in OsNIP2, Oscb5, and OsPLIM2a TF expression between parental lines proposes them as being involved in the control of oxygen flux level in rice roots.

Antiviral Activity of Oroxylin A against Coxsackievirus B3 Alleviates Virus-Induced Acute Pancreatic Damage in Mice.

The flavonoids mosloflavone, oroxylin A, and norwogonin, which were purified from Scutellaria baicalensis Georgi, significantly protected Vero cells against Coxsackievirus B3 (CVB3)-induced cell death. To investigate the in vivo antiviral activity of oroxylin A, we intraperitoneally inoculated CVB3 into 4-week-old BALB/c mice. Body weights and blood glucose levels of the mice were decreased after CVB3 infection, and these changes were attenuated by the administration of oroxylin A. Importantly, treatment of mice with oroxylin A reduced viral titers in the pancreas and decreased the serum levels of the inflammatory cytokines including interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α. Additionally, the administration of oroxylin A mitigated the histological pancreatic lesions and apoptotic cell death induced by CVB3 infection and increased the levels of phospho-eIF2α in infected pancreata. The results suggest that oroxylin A may represent a potent antiviral agent against CVB3 infection.

Effect of various oestrogens on cell injury and alteration of apical transporters induced by tert-butyl hydroperoxide in renal proximal tubule cells.

1. The present study was undertaken in order to examine the effect of various oestrogens on tert-butyl hydroperoxide (t-BHP)-induced cell injury and changes in apical transporters in primary cultured rabbit renal proximal tubule cells. 2. Compared with control, t-BHP (0.5 mmol/L; 1 h) decreased cell viability (62%) and glutathione (GSH) content (60%) and increased lipid peroxide (LPO) formation (309%), arachidonic acid (AA) release (193%) and Ca(2+) influx (168%). 3. The protective potency of various oestrogens for these parameters is dependent on the precise oestrogenic structure, with 2-hydroxy-oestradiol-17 beta (2-OH-E(2)) and 4-OH-E(2), both catecholic oestrogens, or diethylstilbesterol (DES) being more potent than oestradiol (E(2)), oestriol or oestradiol-17 alpha, all phenolic oestrogens (P < 0.05). 4. These cytoprotective effects of oestrogens occur at concentrations above 10 micromol/L and are not dependent on classical oestrogen receptors and gene transcription and translation. In addition, various oestrogens have different preventative effects against t-BHP-induced inhibition of [(14)C]-alpha-methyl-D-glucopyranoside (alpha-MG), inorganic phosphate (Pi) and Na(+) uptake, consistent with the results of cell injury. In contrast, the potency against t-BHP-induced changes in cell viability, LPO, GSH content and transporter function of the anti-oxidants taurine and vitamin C is similar to that of phenolic oestrogens, whereas that of the iron chelators deferoxamine and phenanthroline is similar to that of catecholic oestrogens. 5. In conclusion, various oestrogens have differential cytoprotective potential against t-BHP-induced cell injury and decreases in alpha-MG, Na(+) and Pi uptake. These effects are due, in part, to both the basic chemical properties of the compounds and the maintenance of endogenous GSH or inhibition of AA release and Ca(2+) influx.