Transcription factor CrWRKY42 coregulates chlorophyll degradation and carotenoid biosynthesis in citrus.

Chlorophyll degradation and carotenoid biosynthesis, which occur almost simultaneously during fruit ripening, are essential for the coloration and nutritional value of fruits. However, the synergistic regulation of these 2 processes at the transcriptional level remains largely unknown. In this study, we identified a WRKY transcription factor, CrWRKY42, from the transcriptome data of the yellowish bud mutant "Jinlegan" ([Citrus unshiu × C. sinensis] × C. reticulata) tangor and its wild-type "Shiranui" tangor, which was involved in the transcriptional regulation of both chlorophyll degradation and carotenoid biosynthesis pathways. CrWRKY42 directly bound to the promoter of ß-carotene hydroxylase 1 (CrBCH1) and activated its expression. The overexpression and interference of CrWRKY42 in citrus calli demonstrated that CrWRKY42 promoted carotenoid accumulation by inducing the expression of multiple carotenoid biosynthetic genes. Further assays confirmed that CrWRKY42 also directly bound to and activated the promoters of the genes involved in carotenoid biosynthesis, including phytoene desaturase (CrPDS) and lycopene ß-cyclase 2 (CrLCYB2). In addition, CrWRKY42 could bind to the promoters of NONYELLOW COLORING (CrNYC) and STAY-GREEN (CrSGR) and activate their expression, thus promoting chlorophyll degradation. The overexpression and silencing of CrWRKY42 in citrus fruits indicated that CrWRKY42 positively regulated chlorophyll degradation and carotenoid biosynthesis by synergistically activating the expression of genes involved in both pathways. Our data revealed that CrWRKY42 acts as a positive regulator of chlorophyll degradation and carotenoid biosynthesis to alter the conversion of citrus fruit color. Our findings provide insight into the complex transcriptional regulation of chlorophyll and carotenoid metabolism during fruit ripening.

Tautomeric mixture coordination enables efficient lead-free perovskite LEDs.

Lead halide perovskite light-emitting diodes (PeLEDs) have demonstrated remarkable optoelectronic performance1-3. However, there are potential toxicity issues with lead4,5 and removing lead from the best-performing PeLEDs-without compromising their high external quantum efficiencies-remains a challenge. Here we report a tautomeric-mixture-coordination-induced electron localization strategy to stabilize the lead-free tin perovskite TEA2SnI4 (TEAI is 2-thiopheneethylammonium iodide) by incorporating cyanuric acid. We demonstrate that a crucial function of the coordination is to amplify the electronic effects, even for those Sn atoms that aren't strongly bonded with cyanuric acid owing to the formation of hydrogen-bonded tautomeric dimer and trimer superstructures on the perovskite surface. This electron localization weakens adverse effects from Anderson localization and improves ordering in the crystal structure of TEA2SnI4. These factors result in a two-orders-of-magnitude reduction in the non-radiative recombination capture coefficient and an approximately twofold enhancement in the exciton binding energy. Our lead-free PeLED has an external quantum efficiency of up to 20.29%, representing a performance comparable to that of state-of-the-art lead-containing PeLEDs6-12. We anticipate that these findings will provide insights into the stabilization of Sn(II) perovskites and further the development of lead-free perovskite applications.

Deep-Blue Electroluminescence of Perovskites with Reduced Dimensionality Achieved by Manipulating Adsorption-Energy Differences.

The lagging development of deep-blue perovskite light-emitting diodes (PeLEDs) heavily impedes their practical applications in full-color display due to the absence of spectrally stable emitters and the mismatch of carrier injection capacity. Herein, we report highly efficient deep-blue PeLEDs through a new chemical strategy that addresses the dilemma for simultaneously constant electroluminescence (EL) spectra and high-purify phase in reduced-dimensional perovskites. The success lies in the control of adsorption-energy differences between phenylbutylamine (PBA) and ethylamine (EA) interacting with perovskites, which facilitates narrow n-value distribution. This approach leads to an increased exciton binding energy and enhanced surface potential, hence improving radiative recombination. As a result, an external quantum efficiency of 4.62 % is achieved in PeLEDs with a stable EL peak at 457 nm, demonstrating the best reported result for deep-blue PeLEDs so far.

miR-219 regulates liver cancer stem cell expansion via E-cadherin pathway.

Liver cancer stem cells contribute to tumorigenesis, progression, recurrence and drug resistance of hepatocellular carcinoma (HCC). However, the underlying mechanism for the propagation of liverCSCs is not fully understood yet. Here we show that miR-219 is upregulated in liver CSCs. Knockdown of miR-219 attenuates the self-renewal and tumorigenicity of liver CSCs. Conversely, miR-219 overexpressing enhances the self-renewal and tumorigenicity of liver CSCs.Mechanistically,miR-219 downregulates E-cadherin via itsmRNA 3'UTR in liver CSCs. The correlation between miR-219 and E-cadherin is validated in human HCC tissues. Furthermore, the miR-219 expression determines the responses of hepatoma cells to sorafenib treatment. Our findings indicate that miR-219 plays a critical role in liver CSCs expansion and sorafenib response, rendering miR-219 as an optimal target for the prevention and intervention of HCC.Abbreviations: HCC: Hepatocellular carcinoma; CSCs: cancer stem cells; DMEM: Dulbecco's modified Eagle's medium; FBS: fetal bovine serum; OS: overall survival.

[Comparison of the characteristics of suicide attempters treated in general hospitals with and without prior suicide attempts].

OBJECTIVE: We compared the characteristics of persons who had made multiple versus single suicide attempts to determine whether or not these are two independent subgroups and, thus, should be provided with different preventive services. METHODS: We administered a 2 - 3 hour interview that included a structured psychiatric examination to 325 individuals with suicide attempts who were treated at four city and county-level general hospitals. RESULTS: The age, gender, years of education, marital status, work status, and family economic status of the 52 persons who had made more than one suicide attempt were similar to those of the 273 persons who had made a single attempt. But repeaters were less likely than non-repeaters to live in rural villages and to attempt suicide by ingesting agricultural poisons. Moreover, repeaters considered suicide prior to the attempt for a longer time, had a lower quality of life in the prior month, had a stronger suicidal intent, had more chronic life events, had a higher chronic stress score, and were more likely to have mental illness (P's all < 0.05). CONCLUSIONS: Major differences in the characteristics of suicide attempters with and without a prior history of suicide attempts suggest that these are independent subgroups of attempters. These two types of attempted suicide require different preventive approaches.

Attempted suicide among young rural women in the People's Republic of China: possibilities for prevention.

This article reports on a sample of 147 women under age 35 living in rural areas in China who had attempted suicide and were treated in the emergency room of hospitals in four different locations. The interview instrument took 2 to 3 hours to complete and included audiotaped in-depth interviews with the patient and family members (separately); detailed evaluation of the circumstances surrounding the attempt, life events, and the family environment; and a formal psychiatric evaluation by an attending-level psychiatrist. Overwhelmingly, the method used by the attempters was poisoning with highly lethal pesticides and organic fertilizers. The women's suicidal behavior was characterized by high levels of impulsivity; little effort to seclude themselves before and after ingesting poison; and low rates of mental illness, including depression. Detailed suggestions are made about ways to implement suicide prevention strategies within the particular social and economic context of China.

Risk factors for suicide in China: a national case-control psychological autopsy study.

BACKGROUND: Suicide is the fifth most important cause of death in China, but the reasons for the high rate and unique pattern of characteristics of those who kill themselves are unknown. METHODS: We pretested, and then administered a comprehensive interview to family members and close associates of 519 people who committed suicide and of 536 people who died from other injuries (controls) randomly selected from 23 geographically representative sites in China. FINDINGS: After adjustment for sex, age, location of residence, and research site, eight significant predictors of suicide remained in the final unconditional logistic regression model. In order of importance they were: high depression symptom score, previous suicide attempt, acute stress at time of death, low quality of life, high chronic stress, severe interpersonal conflict in the 2 days before death, a blood relative with previous suicidal behaviour, and a friend or associate with previous suicidal behaviour. Suicide risk increased substantially with exposure to multiple risk factors: none of the 265 deceased people who were exposed to one or fewer of the eight risk factors died by suicide, but 30% (90/299) with two or three risk factors, 85% (320/377) with four or five risk factors, and 96% (109/114) with six or more risk factors died by suicide. INTERPRETATION: Despite substantial differences between characteristics of people who commit suicide in China and the west, risk factors for suicide do not differ greatly. Suicide prevention programmes that concentrate on a single risk factor are unlikely to reduce suicide rates substantially; preventive efforts should focus on individuals exposed to multiple risk factors.