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Rice is the third largest food crop in the world, especially in Asia. Its production in various regions is affected to different degrees by drought stress. Melatonin (MT), a novel growth regulator, plays an essential role in enhancing stress resistance in crops. Nevertheless, the underlying mechanism by which melatonin helps mitigate drought damage in rice remains unclear. Therefore, in the present study, rice seedlings pretreated with melatonin (200 μM) were stressed with drought (water potential of −0.5 MPa). These rice seedlings were subsequently examined for their phenotypes and physiological and molecular properties, including metabolite contents, enzyme activities, and the corresponding gene expression levels. The findings demonstrated that drought stress induced an increase in malondialdehyde (MDA) levels, lipoxygenase (LOX) activity, and reactive oxygen species (ROS, e.g., O2− and H2O2) in rice seedlings. However, the melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively. It activated the expression of ALM1, OsPOX1, OsCATC, and OsAPX2, which increased the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), respectively. Meanwhile, the melatonin pretreatment enhanced the proline, fructose, and sucrose content by inducing OsP5CS, OsSUS7, and OsSPS1 gene expression levels. Moreover, the melatonin pretreatment considerably up-regulated the expression levels of the melatonin synthesis genes TDC2 and ASMT1 under drought stress by 7-fold and 5-fold, approximately. These improvements were reflected by an increase in the relative water content (RWC) and the root-shoot ratio in the drought-stressed rice seedlings that received a melatonin application. Consequently, melatonin considerably reduced the adverse effects of drought stress on rice seedlings and improved rice's ability to tolerate drought by primarily boosting endogenous antioxidant enzymes and osmoregulation abilities. [ABSTRACT FROM AUTHOR]

Background: In this research, an meta-analysis was performed for assessment of the associations between O6-methyguanine-DNA methyltransferase (MGMT) promoter hypermethylation possessing low-grade intraepithelial lesion (LSIL), high-grade intraepithelial lesion (HSIL), cervical cancer (CC), and clinicopathological characters of CC. Methods: Literature selection were conducted through searching PubMed, Web of science, EMBASE, China National Knowledge Infrastructure and Wanfang databases (up to November 2018). An assessment of associations between MGMT methylation and LSIL, HSIL, CC risk and clinicopathological characteristics was performed through pooled odds ratios (ORs) with relevant 95% confidence intervals (CIs). Subgroup analyses, meta-regressions and Galbraith plots were conducted to conduct an exploration on the possible sources of heterogeneity. The genome-wide DNA methylation array studies were extracted from Gene Expression Omnibus (GEO) databases for validation of these outcomes. Results: In this meta-analysis of 25 published articles, MGMT hypermethylation gradually elevated the rates among control group (12.16%), LSIL (20.92%), HSIL (36.33%) and CC (41.50%) specimens. MGMT promoter methylation was significant associated with the increased risk of LSIL by 1.74-fold (P<0.001), HSIL by 3.71-fold (P<0.001) and CC by 7.08-fold (P<0.001) compared with control. A significant association between MGMT promoter methylation with FIGO stage was also found (OR = 2.81, 95% CI: 1.79–4.41, p<0.001). The results of GEO datasets showed that 5 CpG sites in MGMT with a great diagnostic value for the screening of cervical cancer. Conclusion: The meta-analysis indicated the association between MGMT promoter hypermethylation and squamous intraepithelial lesion and cervical cancer. MGMT methylation detection might have a potential value to be an epigenetic marker for the clinical diagnosis of cervical cancer. [ABSTRACT FROM AUTHOR]

Abstract: The two Toll-like receptors, TLR1 and TLR2 were cloned from orange-spotted grouper, Epinephelus coioides, an important teleost fish in mariculture of Asia. The cDNA sequences of TLR1 and TLR2 are 3195 and 3439bp long, with an open reading frame (ORF) of 2406 and 2466bp, encoding 801 and 821 amino acids, respectively. The TLR family motifs, i.e. leucine-rich repeat (LRR) domains and Toll/interleukin (IL)-1 receptor (TIR) domains are conserved in the TLR1 and TLR2, with nine and ten leucine-rich repeat (LRR) domains, and with one TIR domain, respectively. The TLR1 and TLR2 had a constitutive expression in examined organs/tissues of naïve orange-spotted grouper, and an increased expression of TLR1 and TLR2 at mRNA level was observed in immune organs such as in spleen of LPS and Poly(I:C) stimulated fish. An increased expression of TLR1 and TLR2 was also recorded in immune organs of the fish injected with the bacterial pathogen, Vibrio alginolyticus. Similarly, a significant rise in the expression of MyD88, an adaptor molecule which forms signalling complex with intracellular TIR domain, thus leading to the production of pro-inflammatory cytokines, such as IL-1β, was also observed in the LPS- and Poly(I:C)-stimulated, and V. alginolyticus-infected fish, indicating the possible role of TLR1 and TLR2 in the MyD88 signalling pathway. However, the mechanism involved in the increased expression of TLR1 and TLR2 following LPS and Poly(I:C) stimulation is at present unknown in fish, and further research should be carried out to identify ligands of fish TLR1 and TLR2 in order to understand the function of these receptors. [Copyright &y& Elsevier]