[Response of Photosynthetic Bacterial Community to Cadmium Contamination in Paddy Soil].

Heavy metal pollution in rice fields leads to huge losses in rice yield every year and is thus of increasing concern. Therefore, it is important to understand the changes in the microecology and physicochemical properties of paddy soil under different levels of cadmium pollution. The purpose of this study was to investigate the response of the photosynthetic bacterial community in paddy soil to different cadmium pollution levels using 16S sequencing technology. The results showed that pH, total cadmium, and available cadmium content decreased gradually with the increase in cadmium pollution. The soil α diversity was slightly different in the high cadmium (Cd), medium Cd, and low Cd groups; however, the enriched photosynthetic populations and photosynthetic bacterial communities were significantly different among these groups. The effective connections between photosynthetic bacterial species in the high Cd group were significantly greater than those in the medium and low Cd groups, the connections were closer, and the density was higher. Alkaline nitrogen, pH, available (P/K), total (N/P), organic matter, total cadmium, and available cadmium were important factors affecting the photosynthetic bacterial community and were significantly correlated with the photosynthetic bacterial community, explaining 59.90% of the variation in the photosynthetic bacterial community. Effective Cd content was significantly positively correlated with Methylorubrum populi, Methylorubrum extorquens, Methylobacterium sp. Leaf125, and Rhodopseudomonas sp. AAP120 (R>0.05, P<0.05). This study will provide a theoretical basis for the microbial remediation of cadmium contamination in paddy fields. This study is important for understanding the effects of cadmium pollution on specific functional microbial populations in paddy soils.

Preliminary research on the expression, purification and function of the apoptotic fusion protein, Sival.

The objective of the present study was to investigate cloning, expression, and functions of the recombinant protein, Siva1. Siva1 gene was synthesized by RT-PCR from HCT116 cells. Plasmids were cleaved with the restriction endonuclease, BamH1/Sal1 and products were connected to pQE30, which underwent cleavage by BamH1/Sal1. The recombinant plasmid, pQE30-Siva1, was identified after digestion with restriction endonucleases followed by transformation into E. coli M15. Expression of Siva1 was induced by IPTG and identified by SDS- PAGE following purification with affinity chromatography. The results showed that size of Siva1 was 12 kDa, consistent with the molecular weight of the His-Siva1 fusion protein. Functional test demonstrated that Siva1 significantly inhibited the invasion and migration of HCT116 cells. It may thus find clinical application for control of cancers.

[Experimental study of HIF-1alpha antisense oligonucleotide on implanted human gastric cancer in nude mice].

OBJECTIVE: To observe the effect of HIF-1alpha antisense oligonucleotide (HIF-1alpha ASOND) on implanted human gastric cancer in nude mice. METHODS: BALB/c nude mice were subcutaneously transplanted with SCG-7901 tumor cells, then the mice were randomly divided into antisense oligonucleotide (ASOND) group, sense oligonucleotide (SOND) group and the control group. The HIF-1alpha ASOND complexed with cationic liposome, HIF-1alpha SOND complexed with cationic liposome and liposome were injected intra-tumorally in the above groups, respectively. Tumor growth curve in each group animals was observed. The tumor weight was measured and then the rate of inhibition was calculated. The morphological changes of tumor cells was observed under microscope. The expression of HIF-1alpha, VEGF and MVD in tumor tissue was determined by immunohistochemical methods. RESULTS: The growth of tumor of ASOND group was significantly inhibited. There was statistically significant difference (P < 0.05) in the weight of tumor between ASOND group and control group. The inhibitory rates of ASOND group and SOND group were 47.94% and 16.88% respectively, and both inhibitory rates were significantly different (P < 0.01). The tumor tissue expression of HIF-1alpha, VEGF and MVD in ASOND group was significantly lower than those of SOND and the control groups (P < 0.01). CONCLUSION: In tumor tissue, the injection of HIF-1alpha ASOND to treat gastric carcinoma transplanted subcutaneously in nude mice can reduce the expression of HIF-1alpha, consequently reduce the formation of VEGF and new blood vessels, so as to achieve inhibition of tumor growth.