ABSTRACT
Squalene synthase of Alisma orientale catalyzes farnesyl diphosphate (FPP) to form squalene, which is the key regulatory enzyme of the carbon source flow to protostane triterpenes biosynthesis. For further research on the function and expression of AoSS gene, the open reading frame (ORF) of squalene synthase gene (accession no. JX866770) from A. orientale was subcloned into a prokaryotic expression vector pCzn1 and induced the expression of AoSS gene in Escherichia coli BL21(Roseta). The fusion protein was mainly in the form of inclusion bodies and purified to obtain high purity protein. By verifying its functionality through vitro enzymatic reaction, the results showed that the catalytic protein had the catalytic activity of FPP into squalene. In order to research the expression of AoSS in A. orientale, the purified protein was used to immunized rabbits to prepare polyclonal antibody which was then purified, the titer of the antibody was greater than 1∶51 200 by ELISA detection, and displayed good specificity by Western blotting. The prepared antibody was used for immunoassay of AoSS in different organs of A. orientale, and the results showed that the AoSS expression level was the highest in tubers, followed by leaves, and lowest in root. Successful construction of prokaryotic expression vector, validation of gene functions and establishment of rapid immunoassay lay the foundation for further researches on the function and regulation of AoSS gene, and also provide scientific basis on the application of the protostane triterpenes of A. orientale in the field of synthetic biology.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between fetal chromosomal karyotype and early spontaneous abortion, and the effect of the environmental factors on spontaneous abortion.</p><p><b>METHODS</b>Choronic villi from 252 cases of missed abortion were sampled as patient group and 50 normal pregnancies as control group. Chorionic villi were cultured and karyotype analysis was performed by G-banding. Clinical information was collected.</p><p><b>RESULTS</b>The rate of chorion chromosome abnormality in the patient group was 58.09%, significantly higher than that in the control group (4.17%) (P<0.01). Among the 140 cases of karyotype abnormalities, 81 were trisomy, 29 were monosomy X and 17 were polyploidy, accounting for 57.86%, 20.71% and 12.14% of total abnormalities, respectively. Long time and low dose radiation exposure of the pregnant female seemed to be related with spontaneous abortion(P<0.01).</p><p><b>CONCLUSION</b>Chorion chromosome abnormality is a major reason of early spontaneous abortion and karyotype analysis of chorionic villus is of clinical importance. For pregnant women, long-term exposure to computers and television seems a risk factor for missed abortion.</p>