Argonaute proteins are active throughout the lifetime in a variety of organisms and they bind to small RNAs (sRNAs) to regulate gene expression. The Argonaute proteins of vertebrates can be classified into two clades: the Ago clade and the Piwi clade. Both clades have N, L1, L2, PAZ, MID and PIWI domains. The N domain is involved in the loading of sRNAs. L1 and L2 domains facilitate the linking between domains. The PAZ and MID domains exert functions by anchoring sRNAs. The PIWI domain of some Argonaute proteins has RNase H-like structure and exerts the endonuclease function. Ago proteins regulate gene expression at transcriptional and post-transcriptional levels. Piwi proteins mainly exist in the germ cells, silencing transposons in different ways to keep genome integrality and regulating gene expression. In recent years, great progress has been made in Argonaute proteins in terms of the crystal structures, functions, and expression patterns. By reviewing the relevant studies, we elaborate on the structures, sRNA dependence, gene expression regulation, and biological roles of the Ago and Piwi proteins in vertebrates, aiming to clarify the roles of Argonaute proteins in epigenetic regulation and provide a reference for further research and application of these proteins.
Argonaute Proteins/chemistry* ; Animals ; Vertebrates/metabolism* ; Gene Expression Regulation ; RNA, Small Interfering/metabolism* ; Epigenesis, Genetic ; Humans

Objective:To investigate the effect of ginkgo biloba extract (GBE) on oxidative stress in medial prefrontal cortex and excitatory/inhibitory balance of pyramidal neurons in chronic unpredictable mild stress (CUMS)-induced depressive model mice.Methods:Totally 48 SPF grade 7-week-old male C57BL/6J mice were divided into 4 groups according to random number table method: control+ saline group (CTRL+ Veh), control+ GBE group (CTRL+ GBE), model+ saline group (CUMS+ Veh), model+ GBE group (CUMS+ GBE), with 12 mice in each group.Mice in CUMS+ Veh group and CUMS+ GBE group were established by CUMS method, and mice in CTRL+ GBE group and CUMS+ GBE group were intraperitoneally injected with GBE (70 mg/kg) once a day, and mice in CTRL+ Veh group and CUMS+ Veh group were injected intraperitoneally with 0.9% sodium chloride solution.Then, the sucrose preference test, forced swimming test (FST) and tail suspension test (TST) were performed to evaluate the depressive-like behavior of mice, and open field test (OFT) was performed to evaluate the autonomous locomotion and exploration ability and anxiety-like behavior.The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in mPFC were determined by ELISA.Spontaneous excitatory postsynaptic currents (sEPSC) and spontaneous inhibitory postsynaptic currents (sIPSC) were detected by whole-cell recording.SPSS 23.0 was used for data analysis and two-factor analysis of variance(whether to get GBE, whether to mold, show as GBE×CUMS) was used for statistical analysis.Results:(1) Behavioral results: the the time spent in center and total distance of OFT and sugar preference rate of the four groups of mice were compared, and the interaction of GBE×CUMS was significant( F=24.90, 4.82, 3.91, all P<0.05). The results of simple effect analysis showed that the time spent in center ((47.15±3.58) s), the total distance((19.33±0.86) m) and the sugar preference rate((59.11±8.79)%) of the mice in CUMS+ Veh group were lower than those in the CTRL+ Veh group((61.55±2.49) s, (23.24±1.21) m, (84.02±7.45) %) (all P<0.01), and the above indexes in CUMS+ GBE group ((56.51±3.53) s, (20.75±1.31) m, (70.80±11.79)%) were higher than those in CUMS+ Veh group (all P<0.05). In the immobility time of FST and TST of mice in the 4 groups, the interaction of GBE×CUMS were significant( F=85.53, 83.39, both P<0.01). The immobility time of FST and TST in CUMS+ Veh group were higher than those in CTRL+ Veh group (both P<0.01 ), and the above indexes in CUMS+ GBE group were lower than CUMS+ Veh group(both P<0.05). (2)The results of ELISA showed that the interaction of GBE×CUMS of SOD level of mice in the 4 groups was not significant ( F=3.52, P=0.07), but the main effects of GBE factor and CUMS factor were both significant ( F=4.69, 46.93, both P<0.05). The interaction of GBE×CUMS of MDA level was significant( F=16.61, P<0.01). The level of SOD in the CUMS+ Veh group was lower than that in the CTRL+ Veh group ( P<0.01), and the level of SOD in the CUMS+ GBE group was higher than that in the CUMS+ Veh group ( P<0.05). The level of MDA in the CUMS+ Veh group was higher than that of the CTRL+ Veh group ( P<0.01), and the level of MDA in CUMS+ GBE group was lower than that of the CUMS+ Veh group ( P<0.01). (3) The results of whole-cell recording showed that the interaction of GBE×CUMS of frequency and quantification of sEPSC in the four groups were significant ( F=5.45, 6.94, both P<0.05). The sEPSC frequency and quantification in the CUMS+ Veh group were lower than those in the CTRL+ Veh group (both P<0.01), and the sEPSC frequency and quantification in CUMS+ GBE group were higher than those of CUMS+ Veh group (both P<0.05). The interaction of GBE×CUMS of frequency and quantification of sIPSC in the four groups were significant ( F=7.78, 8.96, both P<0.01). The sIPSC frequency and quantification of the CUMS+ Veh group were higher than those of CTRL+ Veh group (both P<0.01), and the above indexes of CUMS+ GBE group were lower than those of CUMS+ Veh group (both P<0.01). As for the sEPSC/sIPSC ratio, GBE×CUMS interaction was significant ( F=5.45, P=0.02). The sEPSC/sIPSC ratio of CUMS+ Veh group (0.09±0.01) was lower than that of CTRL+ Veh group (0.28±0.04) ( P<0.01), and the sEPSC/sIPSC ratio of CUMS+ GBE group (0.14±0.03) was higher than that of CUMS+ Veh group ( P<0.05). Conclusion:Ginkgo biloba extract can improve the depression-like behavior of mice induced by CUMS, reduce the oxidative stress of mPFC and improve the excitation/inhibition balance of pyramidal neurons in depressive model mice.

Objective To compare the detection performance of the modified serum test (TRUST) method and the traditional method in syphilis screening.Methods A series of TRUST high titer syphilis serum was diluted,and the positive rate of each method was calculated by using the improved method and the traditional method.Comparison of two detection methods of C50,C5 ～ C95 interval,as well as the accuracy of the density curve,and the consistency of the two methods were compared,and diagnostic performance were compared.Results The improved method of C50 was less than the traditional method of C50,and the improved method of C5 ～ C95 range was narrower than the traditional method,compared with the traditional method.The improved method of the non precision density curve was steeper than the traditional method,and the two confidence interval of the consistency degree of the 95％ methods was 73.4％ to 95.8％.The diagnostic sensitivity (SEN),diagnostic specificity (SPE),positive predictive value (PPV),negative predictive value (NPV) and diagnostic efficiency(DF) of the improved method were 64.29 ％,99.1％,85.71％,97.05 ％ and 96.39 ％,respectively.The SEN,SPE,PPV,NPV and DF of the traditional methods were 3.75 ％,98.49 ％,75 ％,96.18 ％ and 95 ％,respectively.The improved method was superior to the traditional methods in the two aspects of SEN and PPV (x2 =8.25,10.03,all P＜0.05),with the statistically significant difference.The improved method was slightly higher than the traditional method in SPE,NPV and DF (x2 =2.39,3.45,4.03,all P＞0.05),with the no statistically significant difference.Conclusion The precision,diagnostic sensitivity and diagnostic specificity of the improved method was higher than that of the traditional method,and it can be applied to the detection of large batch samples with the aid of the full automatic enzyme immunoassay instrument.The improved method can be used to replace the traditional method for syphilis screening.

Objective The purpose of our research was to quantitative study the degeneration of lumbar intervertebral discs by using T2 mapping technology at 3.0T MR and research the correlation of biomechanics and lumbar disc degeneration.Methods 34 patients with low back pain or sciatica were enrolled.The correlation of T2 values of lumbar intervertebral discs and Pfirrmann grading,disc location,patient ages were analyzed.T2 values before and after loading were also analyzed.Results T2 values of nucleus pulposus were correlation with Pfirrmann scoring,disc location and,patient ages.Conclusion (1 )T2 mapping provides a non-invasive and quantitative way to diagnose lumbar discs degeneration.(2)The change of external pressure load can affect the T2 values of the intervertebral disc.