Expression profiling of yield related genes in rice cultivars under terminal drought stress.

BACKGROUND: Rice crop may experience a significant reduction in yield-up to 50%-due to two occurrences during drought stress: unsuccessful peduncle elongation in panicle exertion and ineffective grain filling. The comprehension of mechanisms that promote drought tolerance during these growth phases is crucial for the production of rice that can withstand drought conditions, thus averting a decrease in crop yield. METHODS AND RESULTS: The expression of two xyloglucan endo transhydrolase/glucosylase genes (OsXTH 5 and 19) in peduncle tissue and a sucrose transporter gene (OsSUT1) in flag leaf sheath were assessed. An experiment was carried out in a factorial arrangement based on completely randomized design in which, factor A was two rice cultivars (Vandana as tolerant and Tarom mahalli as local susceptible to drought) and factor B was five drought stress treatments (full irrigation, drought stress duration in 72 and 96 h, re-watering after 120 and 192 h). Results showed that expression of OsXTH19 and OsXTH5 genes were upregulated in both Vandana and Tarom mahalli cultivars due to stress treatments. OsXTH19 expression was found to decrease while OsXTH5 expression increased during re-watering treatments. It is likely that the persistence of peduncle growth in the drought-tolerant Vandana cultivar can be attributed to the presence of OsXTH19 under drought conditions and OsXTH5 after re-watering. The expression of OsSUT1 in flag leaf sheath of Vandana in re-watering treatments was reached 8-60-fold re-watering. CONCLUSIONS: Peduncle elongation was attributed to two XTH genes under drought stress condition. Panicle exertion may be promoted by sustaining peduncle growth despite drought stress. Consequently, this may led to reduce in non fertile florets and decrease in grain yield by 50%. As grain filling depend to expression of OsSUT1 in flag leaf sheath under drought stress, to improve rice cultivars under aerobic production system and drought stress, it is advised to apply these findings in rice breeding programs.

Intravenous methylprednisolone pulse as a treatment for hospitalised severe COVID-19 patients: results from a randomised controlled clinical trial.

INTRODUCTION: There are no determined treatment agents for severe COVID-19. It is suggested that methylprednisolone, as an immunosuppressive treatment, can reduce the inflammation of the respiratory system in COVID-19 patients. METHODS: We conducted a single-blind, randomised controlled clinical trial involving severe hospitalised patients with confirmed COVID-19 at the early pulmonary phase of the illness in Iran. The patients were randomly allocated in a 1:1 ratio by the block randomisation method to receive standard care with methylprednisolone pulse (intravenous injection, 250 mg·day-1 for 3 days) or standard care alone. The study end-point was the time of clinical improvement or death, whichever came first. Primary and safety analysis was done in the intention-to-treat (ITT) population. RESULTS: 68 eligible patients underwent randomisation (34 patients in each group) from April 20, 2020 to June 20, 2020. In the standard care group, six patients received corticosteroids by the attending physician before the treatment and were excluded from the overall analysis. The percentage of improved patients was higher in the methylprednisolone group than in the standard care group (94.1% versus 57.1%) and the mortality rate was significantly lower in the methylprednisolone group (5.9% versus 42.9%; p<0.001). We demonstrated that patients in the methylprednisolone group had a significantly increased survival time compared with patients in the standard care group (log-rank test: p<0.001; hazard ratio 0.293, 95% CI 0.154-0.556). Two patients (5.8%) in the methylprednisolone group and two patients (7.1%) in the standard care group showed severe adverse events between initiation of treatment and the end of the study. CONCLUSIONS: Our results suggest that methylprednisolone pulse could be an efficient therapeutic agent for hospitalised severe COVID-19 patients at the pulmonary phase.

Superior adaptation of aerobic rice under drought stress in Iran and validation test of linked SSR markers to major QTLs by MLM analysis across two years.

Drought is one of the biggest challenges for rice (Oryza sativa L.) production in rainfed areas. Developing "aerobic rice" cultivars could be a valuable alternative to irrigated/rainfed areas. During 2010-2013, 115 rice genotypes, including non-local cultivars and aerobic rice genotypes, were evaluated and 31 rice genotypes were screened, while 21 Iranian lowland rice cultivars (52 genotypes) were investigated under non-stress and drought conditions at the University of Guilan, Rasht, Iran, in 2014 and 2017. The results revealed the superiority of high yielding genotypes, namely Neda (6.202 t ha- 1), IR82639-B-B-140-1 (6.020 t ha- 1), and IR82635-B-B-82-2 (5.75 t ha- 1) under non-stress, Panda (4.512 t ha- 1), and IR82639-B-B-140-1 (4.08 t ha- 1), under drought stress conditions. Based on the molecular markers evaluation using identified SSR markers linked to major QTLs different important traits specially drought stress, IR 82639-B-B-140-1 showed the highest genetic distance with high-quality Iranian lowland cultivars, which could be considered as a donor for the development of new cultivars. Moreover, the assignment of rice genotypes based on Jaccard distance clustering was in agreement with the grouping of structure analysis. The validation test using MLM analysis in this natural population revealed the most important significant associations that were identified under drought conditions. These are: the associations between RM306, RM319, RM511, RM28166, and RM11943 with different grain yield (GY)-related traits simultaneously and stable across both years. These markers, which were verified in a natural population across 2 years, could be considered as the potential markers for use in marker-assisted breeding and to improve the grain yield of rice.

Identification of CBF14 and NAC2 Genes in Aegilops tauschii Associated with Resistance to Freezing Stress.

Low temperature as one of the most important environmental factors limits the productivity of plants across the world. Aegilops, as a wild species of Poaceae, contains low temperature-responsive genes. In this study, we analyzed morphological (wilting, chlorosis, and recovery) and physiological (ion leakage) characteristics to identification of a cold-tolerant genotype. In this experiment, we introduced two transcription factors (TFs) in Aegilops species for the first time. Bioinformatics analysis demonstrated that our nucleotide sequences have high similarity with CBF14 (C-repeat-binding factor) and NAC2 (NAM, ATAF, and CUC) in Triticum aestivum. Based on the physiological and morphological data, one genotype (Aladizgeh) was identified as the most resistant genotype which was selected for further gene expression analysis. The real-time PCR results indicated that the CBF14 gene was not expressed 3 h following cold treatment, but the highest expression was observed after 6, 12, and 24 h of cold treatment; however, a sudden decrease was observed in its expression after 30 h. The NAC2 gene also was not expressed 3 h after cold stress, but the highest expression was at 24 h and similar to the CBF14 gene; its expression suddenly decreased after 30 h. Our results indicated that this genotype can tolerate -4 °C for 3 h, but the CBF14 and NAC2 genes were activated when treated for longer durations. Expression of TFs studied in this experiment had decreased after 30 h, in which cell death seems to be the important reason.

Nanorod vanadatesulfuric acid as a novel, recyclable and heterogeneous catalyst for the one-pot synthesis of tetrahydrobenzopyrans.

Vanadatesulfuric acid (VSA), as a novel and heterogeneous nanorod catalyst, was used for an efficient synthesis of tetrahydrobenzo[b]pyrans using an aldehydes, 1,3-cyclohexanediones or beta-ketoester and malononitrile in C2H5OH/H2O mixture under reflux conditions. VSA is prepared via the reaction of sodium metavanadate and chlorosulfonic acid in high purity. The catalyst was characterized by FT-IR, XRD, TEM and EDAX analysis. Compared to the conventional method, this method consistently has the advantage of high yields, simple workup, short reaction times and reusability of the catalyst.

Preparation of microparticles of naproxen with Eudragit RS and talc by spherical crystallization technique.

Microparticles of naproxen with Eudragit RS and talc were prepared by the spherical crystallization technique, i.e. quasi-emulsion solvent diffusion method. The obtained microparticles were evaluated by micromeritic properties, yield, encapsulation efficiency, drug physical state and dissolution rate of drug. The influence of formulation factors and preparation condition (drug: polymer ratio, talc: polymer ratio, SLS concentration, stirring speed) on the properties of the microparticles were also examined. The resultant microparticles were finely spherical and uniform with high incorporation efficiency and yield. Greater encapsulation efficiency was obtained by increasing the drug: polymer ratio and talc: polymer ratio and by reducing the SLS %. The dissolution rate of naproxen from microparticles was enhanced significantly with increasing the ratio of drug: polymer and stirring rate, and sustained by increasing SLS % in crystallization medium. The results of X-ray diffraction and differential scanning calorimeter analysis indicated that naproxen was highly dispersed in microparticles, so as amorphous state. Studies carried out to characterize the micromeritic properties of formulations, such as flowability and packability showed that microparticles were suitable for further pharmaceutical manipulation (e.g. capsule filling). Hence, the spherical crystallization technique can be successfully used for obtaining spherical microparticles, generating a heterogeneous matrix system and providing sustained drug release.

Mild and efficient oxidation of Hantzsch 1,4-dihydropyridines with sodium periodate catalyzed by a new polystyrene-bound Mn(TPP)Cl.

Mild and efficient oxidation of Hantzsch 1,4-dihydropyridines with sodium periodate catalyzed by Mn(TTP)Cl supported on polystyrene-bound imidazole is reported. This heterogeneous catalyst is of great stability and reusability in the oxidation of 1,4-dihydropyridines with sodium periodate without significant loss of its catalytic activity.

Rapid and efficient oxidation of Hantzsch 1,4-dihydropyridines with sodium periodate catalyzed by manganese (III) Schiff base complexes.

Rapid and efficient oxidation of Hantzsch 1,4-dihydropyridine with sodium periodate is reported. The Mn(III)-salophen/NaIO4 catalytic system converts 1,4-dihydropyridines to their corresponding pyridine derivatives at room temperature in a 1:1, CH3CN/H2O mixture. The ability of various Schiff base complexes in the oxidation of 1,4-dihydropyridine was also investigated.

Biomimetic oxidation of Hantzsch 1,4-dihydropyridines with tetra-n-butylammonium periodate catalyzed by tetraphenylporphyrinatomanganese(III) chloride [Mn(TPP)Cl].

Efficient oxidation of Hantzsch 1,4-dihydropyridines to their corresponding pyridine derivatives with (Bu(4)N)IO(4) catalyzed by tetraphenylporphyrinatomanganese(III) chloride [Mn(TPP)Cl] is reported. This catalytic system shows high efficiency in the oxidation of 1,4-dihydropyridines at room temperature in the presence of imidazole.