[Community stability for spruce-fir forest at different succession stages in Changbai Mountains, Northeast China].

Based on the analysis of three forest communities (polar-birch secondary forest, spruce-fir mixed forest, spruce-fir near pristine forest) in Changbai Mountains, a total of 22 factors of 5 indices, including the population regeneration, soil fertility (soil moisture and soli nutrient), woodland productivity and species diversity that reflected community characteristics were used to evaluate the stability of forest community succession at different stages by calculating subordinate function values of a model based on fuzzy mathematics. The results that the indices of population regeneration, soli nutrient, woodland productivity and species diversity were the highest in the spruce-fir mixed forest, and the indices of soil moisture were the highest in the spruce-fir near-pristine forest. The stability of three forest communities was in order of natural spruce-fir mixed forest > spruce-fir near pristine forest > polar-birch secondary forest.

Quantification of plasma hTERT DNA in hepatocellular carcinoma patients by quantitative fluorescent polymerase chain reaction.

PURPOSE: To investigate the levels of human telomerase reverse transcriptase (hTERT) DNA in the plasma of patients with hepatocellular carcinoma (HCC), and to evaluate the diagnostic value and correlation of hTERT DNA with clinical parameters in HCC. METHODS: A real-time quantitative fluorescent polymerase chain reaction (FQ-PCR) system was designed and evaluated. Plasma samples were collected from 60 HCC patients, 21 patients with hepatitis B virus (HBV) and 29 healthy controls. Plasma DNA was extracted and quantified by FQ-PCR. The diagnostic value of plasma hTERT DNA levels and their relationships with clinical characteristics were analyzed statistically. RESULTS: Plasma levels of hTERT DNA in HCC patients were significantly higher than in HBV patients (4.18×104±4.94×104 copies/µl vs 1.21×104±6.63×103 copies/µl, P=0.003) and healthy controls (4.18×104±4.94×104 copies/µl vs 1.44×104±6.61×103 copies/µl, P < 0.001). Receiver operating characteristic curve analysis indicated a sensitivity of 64% and a specificity of 90% for the ability of hTERT DNA levels to detect malignancy at a cutoff value of 1.87×104 copies/µl. Association analysis revealed that plasma hTERT DNA levels were closely related to tumor size, portal vein cancer embolus and TNM stage (P=0.013, P=0.010, and P=0.029, respectively), but were not associated with lymph node metastasis, hepatitis B surface antigen, or α-fetoprotein (AFP) (all P > 0.05). The levels of plasma hTERT DNA in HCC patients with AFP ≤20 ng/ml were significantly higher than in HBV patients (4.59×104±4.98×104 copies/µl vs 1.44×104±6.63×103 copies/µl, P=0.016) and in healthy controls (4.59×104±4.98×104 copies/µl vs 1.21×104±6.63×103 copies/µl, P=0.001). CONCLUSIONS: Quantitation of plasma hTERT DNA by FQ-PCR may provide a novel complementary tool with potential clinical applications for the screening and detection of HCC. Plasma hTERT DNA has the potential to be a broad tumor marker for common cancers.

[Study on the disposal process for removing heavy metal ions from wastewater by composite biosorbent of nano Fe3O4/Sphaerotilus natans].

Composite biosorbent nano Fe3O4/Sphaerotilus natans was prepared when nano Fe3O4 was used as carrier, then the composite biosorbent characterized by infrared instrument and investigated on adsorbing heavy metal ions from wastewater. Infrared spectrum analysis shows that--CONH--and--OH are principal activated groups of composite biosorbent. The experiment of adsorption shows that biomass concentration and flow velocity are main influencing factors. The composite biosorbent has best effect on the adsorption of Cu2+ under the conditions of biomass 1.5 g/L (Sphaerotilus natans/Fe3O4 = 3:2), flow velocity 0.96 L/h and initial concentration of Cu2+ was less than 20 mg/L. Composite biosorbent can be used for more 10 times when biosorbent was regenerated by HCl solution, and HCl solution can be used 3 times repeatedly. The selective sequence was Ph2+ > Cu2+ > Zn2+ > Cd2+.

[Advances in the Study on Marker Genes in transgenic Plants.].

Plant transgenic engineering is becoming more and more important in the world. The safety of selectable marker genes in the transgenic plants has been noticed widely. The new advances of selectable markers in transgenic plants were reviewed in this paper in three aspects. The first is the establishment of transformation systems allowing resistant marker genes to be eliminated from the transgenic plants, including co-transformation, site-specific recombination and transposition, as well as other methods. In these ways, the transgenes can be inserted into transgenic plants more than once. The second is the utilization and development of bio-safe positively selective marker genes, mainly referred to the carbohydrates metabolism genes, the stress- resistant enzymatic genes and the green fluorescent protein(GFP) gene. At the same time, the mercuric reductase genes, the key genes for chloroplast synthesis and other genes should also be quickly developed as markers. The third is the establishment of marker-free and skelecton-free transformation vector systems, which are efficient and simple. The prospects in application of these novel methods, marker free and safe selectable markers are also viewed in the article.