Multiple microRNAs control ecdysone signaling in the midgut of Spodoptera litura.

Metamorphosis is one of the most important physiological processes in insects. It is regulated by a serial of ecdysone cascade genes. Recently, lots of microRNAs (miRNAs) were investigated in insects; however, their function in metamorphosis is largely unknown. In the present study, the dynamics of a small RNA population was investigated by RNA sequencing from the midgut of a lepidopteran pest Spodoptera litura during larval-pupal metamorphosis. A total of 101 miRNAs were identified, and 75 miRNAs were differentially expressed during the metamorphic process. The relationship between these differentially expressed miRNAs and 12 ecdysone cascade genes was analyzed by four classical software programs, and a multiple-to-multiple regulatory network was found to exist between these miRNAs and their targets. Among them, miR-14-3p and its two targets (EcR and E75) were chosen for further validation. MiR-14-3p had higher expression level in the 6th instar larvae as compared with either the prepupae or pupae, which was opposite to that of both EcR and E75, two ecdysone cascade genes. Luciferase reporter assay confirmed that both EcR and E75 were regulated by miR-14-3p. Interestingly, the 3' untranslated regions are nearly identical to each other among different transcript variants of the ecdysone cascade genes, including EcR, USP, E75, E74, E78, E93, Hr3, Hr4, Hr39, Krh1 and Ftzf1. Thus, different transcript variants of one ecdysone cascade gene could be regulated by the same miRNA. The above data suggest that the ecdysone signaling pathway is under the tight control of miRNA. These findings expand our understanding of the mechanism of insect metamorphosis and may also provide a novel possibility for the control of pest insects in the future.

Study on the configuration and training of doctors and nurses in the healthcare service institutions in Heilongjiang Province / 中华医学教育探索杂志

Objective To describe and analyze the status quo of the doctor and nurse configuration in Heilongjiang Province,and to study their cultivation condition while predicting the number of medical staff.Methods Through the health workforce database of Heilongjiang Province in 2014,using Excel 2007 statistical software,the status quo of doctor and nurse configuration was analyzed.The grey prediction model was also used to analyze the number of medical staff in Heilongjiang province from 2004 to 2014,and the number of medical staff in Heilongjiang province from 2016 to 2018 was predicted.Results Up to 2015,the number of doctors and nurses in Heilongjiang Province accounted for 0.42％ of the total population,composed of mainly young and middle-aged staff and mostly with bachelor's degree and junior college certificate.Doctor-to-nurse ratio was 1:0.96.The grey prediction model indicated that the number of medical staff in Heilongjiang Province would increase year by year,and the inversion of doctor-to-nurse ratio would be eased.Conclusion The reform and development of medical education in Heilongjiang Province has promoted the optimization of the professional title structure and educational structure.It is expected that by 2016 Heilongjiang medical care ratio inversion problem will be completely resolved.