MicroRNAs are abundant in the brains of vertebrates and some show a brain-specific or brain-enriched expression pattern. Because microRNAs regulate the expression of hundreds of target genes, it is not surprising that they have profoundly important functions in brain development and pathological processes. For example, miR-124 plays an important role in inducing and maintaining neuronal identity through targeting at least two anti-neural factors. MicroRNAs have also been implicated in brain disorders, including brain tumors and neurodegenerative diseases. This review aims to present an overview of the expression profiles and functions of microRNAs in the developing brains of vertebrates.
Yanting QiYu ZhaoZhuyin ChenXiaona ChenMarie C. LinXiangfu KongLihui Lai
To understand the operation principle of the modular multilevel converter(MMC)deeply,it is necessary to study the harmonic characteristics of the MMC theoretically.Besides,the analytical harmonic formulas of the MMC are useful in designing the main circuit,reducing the losses and improving the waveform quality.Based on the average switching function and the Fourier series harmonic analysis,this paper deduces the analytical expressions for such electrical quantities as the arm voltage,the arm current,the capacitor voltage,the capacitor current and the circulating current of the MMC.Finally,a digital model of a 21-level MMC-HVDC system is realized in PSCAD/EMTDC.The results of the analytical expressions coincide with the simulation results,which verify the effectiveness and feasibility of the proposed analytical expressions.
Objective To study the new triterpene glycosides from sea cucumber Holothuria scabra with cytotoxic activity. Methods Triterpene glycosides from H. scabra were separated and purified by chromatography on DA-101, silica gel, and reversed-phase silica gel column, as well as RP-HPLC. Their structures were elucidated on the basis of spectral data and chemical evidence. Results Three triterpene glycosides were identified as scabraside D (1), fuscocineroside C (2), and 24-dehydroechinoside A (3). Their inhibition on P-388, A549, MKN-28, HCT116, and MCF-7 cells were significant. Conclusion Scabraside D (1) is a new triterpene glycoside, and compounds 2 and 3 are isolated from H. scabra for the first time. The glycosides 1-3 show the in vitro cytotoxicity against five human tumor cell lines in comparison to 10-hydroxycamptothecin.
Hua HANLing LIYang-hua YIXiao-hua WANGMin-xiang PAN
The gene encoding the 18 kDa protein of Taenia solium metacestodes was amplified by RT-PCR and cloned into the pGEM-T vector for sequencing.The recombinant plasmid named pGEX-CE18 was constructed and transformed into E.coli BL21 for in vitro expression.SDS-PAGE and Western blot were employed for analyzing the recombinant protein,which was then used for development of an indirect ELISA for detection of anti-cysticercosis antibodies.The results showed that the recombinant protein of interest was 35 kDa in size,accounting for 28%of total bacteria proteins,and reacted with positive sera against cysticercosis.Using the newly-constructed indirect ELISA and a commercially available ELISA kit,paired analyses of 178 serum samples indicated that the concordant rate was 98.83%and the ELISA exhibited good specificity and sensitivity,supporting its utility and application for diagnosis of cysticercosis.
A total of 321 individuals from six cattle populations of four species in a bovine subfamily in China were studied using 12 pairs of microsatellite markers. The genetic diversities within and between populations were calculated. The phylogenetic trees were constructed by （δμ）^2 and DA distances, and the divergence times between populations were estimated by （δμ）^2. Altogether, 144 microsatellite alleles were detected including 24 private alleles and nine shared alleles. Chinese Holstein had the largest number of private alleles （10）, whereas Bohai black and Buffalo had the smallest number of private alleles （2）. Chinese Holstein showed the highest genetic variability. Its observed number of alleles （Na）, mean effective number of alleles （MNA）, and mean heterozygosity （He） were 7.7500, 4.9722, and 0.7719, respectively, whereas, the Buffalo and Yak showed low genetic variability. In the phylogenetic trees, Luxi and Holstein grouped first, followed by Bohai and Minnan. Yak branched next and buffalo emerged as the most divergent population from other cattle populations. Luxi and Bohai were estimated to have diverged 0.039-0.105 million years ago （MYA）, however, buffalo and Holstein diverged 0.501-1.337 MYA. The divergence time of Yak versus Minnan, Holstein and buffalo was 0.136-0.363, 0.273-0.729, and 0.326-0.600 MYA, respectively.
Yongjiang Mao Hong Chang Zhangping Yang Liu Zhang Ming Xu Guobin Chang Wei Sun Guangming Song Dejun Ji
Objective To establish a sandwich ELISA method for detecting vascular endothelial growth factor （VEGF） in sera of population and the patients with hepatocellular carcinoma （HCC）. Methods Full length and two truncated human VEGF cDNA sequences were amplified from a commercial plasmid pBLAST49-hVEGF by PCR and inserted into the prokaryotic-expression plasmid pET-32a or pGEX-2T. Various VEGF proteins were expressed and purified from E. coli in His-Trx or GST fusion forms. The specific VEGF antibodies were elicited in experimental rabbits and mice by immunization of the full length VEGF fusion protein His-Trx-VEGF1-165. After purification of antibodies with chromatograph of Protein G, a sandwich ELISA technique was established. Serum VEGF levels were evaluated in 229 adults and 291 HCC patients. Results SDS-PAGE displayed that the molecular weights of the expressed full length （His-Trx-VEGF1-165）, N-terminal （His-Trx-VEGF1-100） and C-terminal （GST-VEGF100-165） human VEGF fusion proteins were about 38KD, 31KD, and 33KD, respectively. Western blots confirmed that the prepared antisera were able to recognize both prokaryoticly and eukaryoticly expressed recombinant VEGF proteins. Assays of serially diluted His-Trx-VEGF1-100 by the established sandwich ELISA method showed that the linear range of the standard curve was 0.625-320 ng/mL, with the squared correlation coefficient R^2=0.991. Screening of a serum panel containing 291 serum samples of HCC patients and 229 health adults revealed that the average VEGF level in HCC patients was higher than that in healthy controls, with a statically significant difference. Conclusion The established sandwich ELISA reflects the level of serum VEGF and provide scientific basis for screening metastasis and recurrence of HCC using serum VEGF as an index.
In order to discover the relation between rock-soil thermal properties and strata during the process of engineering investigation,the authors studied the measuring principle of Thermal Conductivity Scanner( TCS)and measured the thermal properties of 45 drilling samples from Qinghai with TCS in the laboratory. The results show that the specific heat capacity( SHC) decreases while the thermal conductivity( TC) increases with the increase of the depth. With the lithological change,the specific heat capacity and thermal conductivity have the opposite trend. The depth and lithology have a greater influence on the thermal conductivity than the specific heat capacity.
