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Based on the 1:250 000 land quality geochemical survey data of black land in Northeast China, the soil nutrients, soil environmental quality, comprehensive soil quality and suitability of green food producing area in Nehe City are evaluated according to the Soil Quality Geochemical Evaluation Standard and Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial). The results show that there is fertile land and clean environment in Nehe City, which is suitable for the development of green agriculture. Among the 16 indexes, including N, P, K, organic matter, CaO, MgO, Fe2O3, S, B, Zn, Mn, Cu, Mo, Co, Ge and V, except Cu and Zn are relatively deficient, Ge and B deficient, the others are rich or relatively rich. The comprehensive soil nutrient grades are mainly rich and medium, with distribution areas of 3 666.74 km² and 2 574.11 km², accounting for 56.94% and 39.97% of the total area respectively. The soil environmental quality is dominated by Grade I (risk free), covering an area of 6 435.78 km², accounting for 99.94% of the total; while the Grade II (risk controllable) area is only 4 km², occupying 0.06%. The comprehensive soil quality is largely fine-grade soil, covering 3 806.06 km² and accounting for 59.11% of the total area, with the good-grade of 2 574.11 km² (39.97%) and medium-grade of 59.61 km² (0.92%), no poor- and inferior-grades soil. The soil area conforming to Grade-AA green food production area is 6 461.5 km², accounting for 97.5% of the total area, that conforming to Grade-A 38.1 km² (0.58%), and that does not meet the requirements is 65.6 km² (0.99%). [ABSTRACT FROM AUTHOR]

Based on the remote sensing monitoring data of land use in 1985, 2000 and 2017, the spatiotemporal variation characteristics and eco-environmental effects of land use transition in eastern Songnen Plain in the past 30 years are analyzed by means of land use transfer matrix, gravity center model and eco-environment quality index. The results show that the land use is mainly cultivated land and forest land with clear distribution boundary during 1985-2015. The land use intensity continues to increase, fast in early stage and slow in later. The main performances of land use transition involve continuous increase of agricultural land, continuous decrease of ecological land and slight increase of construction land, changing drastically in early stage and slowing down in later. The direction of land use transition is generally stable. The shift trajectory of transfer barycenter varies greatly, of which the largest change is during 1985-2000, with the transfer trajectory of water area shifting 76.34 km northwestward. The regional ecoenvironmental quality index of Songnen Plain continued to decline from 0.395 in 1985 to 0.361 in 2017, indicating the continuous deterioration of eco-environmental quality. In 2017, the spatial distribution is dominated by medium and low-medium quality areas. The mutual transition between agricultural land, grassland and unused land is the main influencing factor of ecological environment quality. [ABSTRACT FROM AUTHOR]

Based on the massive geochemical data obtained from the national multi-target land survey, taking the deep-soil samples from Songnen Plain as the research object, the anomaly characteristics of halogen elements, total carbon (TC) and CaO, combined with the geological features, are used to predict the oil-as reservoirs in Songnen Plain. A total of 3 prospective areas are delineated, among which YQ-1 is located on the east of Daqing Oilfield, with great potential of oil-gas reservoir, YQ-2 and YQ-3 with the potential for further discovery of reservoir. [ABSTRACT FROM AUTHOR]

Keshan County in Heilongjiang Province is the place after which the endemic Keshan disease was named. By analyzing 809 topsoil samples (0-20 cm) and 205 deep-soil samples (150-200 cm), the paper studies the characteristics of selenium (Se) content in soil and crop seeds and available Se content by different soil types. The results show that the average Se content in surface soil is 0.249x10-6, lower than the national average and higher than that of the world and Heilongjiang Province in Northeast China Plain, mainly characterized by Se-sufficiency, with the area accounting for 93.95%. The average Se content in deep soil is 0.167x10-6, obviously lower than that in surface soil, with the Se-low and Se-deficient soil areas making up 62.62%. The Se content in surface layer of different soil types from high to low is chernozem and meadow soil (the same), followed by black soil and dark brown soil. On the contrary, the Se content in deep layer is dark brown soil, black soil, meadow soil and chernozem in order. The Se content of different land use types show that the Se content in construction land and cultivated land is high, that in forest land and water conservancy land low, indicating the Se content is obviously affected by human activities. The Se content in seeds of main crops such as maize, soybean and rice is 0.033x10-6 averagely, showing the characteristics of low-Se. [ABSTRACT FROM AUTHOR]

Based on the 1 : 250 000 land quality geochemical survey data of the main cultivated lands in eastern Oroqen Qi, Inner Mongolia, the paper ascertains the organic carbon storage in surface and deep soils and distribution characteristics of organic carbon density in the study area, analyzes the relation of soil organic carbon storage and density to soil type and land use pattern, and discusses the effect mechanism of soil type and land use pattern on soil organic carbon. The results show that the soil organic carbon is unevenly distributed, with soil type and land use pattern as the main factors affecting soil organic carbon storage and density. [ABSTRACT FROM AUTHOR]

The study on the characteristics of major nutrient elements in typical black soil areas before and after reclamation is important for sustainable utilization of black soil resources and protection of the breadbasket in Northeast China. Four sections are laid out in the typical black soil areas where land use has not changed for the past 40 years in Helen area, eastern Songnen Plain, to make a comparative study on the main index elements for soil fertility (organic matter, total nitrogen, total phosphorus, C:N and pH value) in the sections before and after reclamation. The results indicate that the contents of organic matter, total nitrogen and total phosphorus show a change trend of rapid decrease through slow decrease to basically stable with soil depth. Although reclamation has changed the content of nutrient elements in soil, it does not change the content variation rule with soil depth. Reclamation affects the pH value of black topsoil to a certain extent, which led to slow acidification of cultivated land. The research results will expectedly provide scientific basis for sustainable utilization, protection and restoration of black soil resources. [ABSTRACT FROM AUTHOR]

Objective: To construct a rheumatoid arthritis-specific full-length fully human mammalian display antibody libraries., Methods: Peripheral blood lymphocytes were isolated from patients with rheumatoid arthritis. The repertoires of kappa light chain (LCκ) and heavy chain variable region (VH) of the antibodies were amplified by RT-PCR. The amplified LCκ and VH genes were inserted into the vector pDGB-HC-TM separately, and the ligated libraries were transformed into competent E.coli TOPO-10 strain to construct the rheumatoid arthritis-specific antibody heavy and light chain libraries. 293T cells were co-transfected with the libraries and the full-length fully human antibody expressed on the surface of 293T cells were analyzed by flow cytometry., Results: The libraries of rheumatoid arthritis-specific antibody LCκ and heavy chain (IgG1) were constructed. The expression of full-length fully human antibody on the surface of 293T cells was confirmed by flow cytometry. With the rates of correct LCκ and heavy chain sequence insertion reaching 80% and 60%, respectively, as shown by DNA sequence analysis of the randomly selected clones, the libraries showed an expressible combinatory diversity of 6.13×10(10)., Conclusion: The constructed libraries provide a useful platform for screening rheumatoid arthritis-specific antibodies.

Objective: To investigate the expression characteristics of Gluc-Fluc dual luciferase plasmid after its transfection into MB49 bladder cells., Methods: pAAV2neoCAG-Gluc-2A-Fluc and pAAV2neo-Gluc plasmids were separately transfected into MB49 cells via LipofectamineTM2000. The Gluc activity in the cell culture supernatant and the Fluc activity in the cells were detected by luminometer and Lumina Imaging system., Results: The luminometer result showed that the activity of Gluc in the supernatant increased gradually in a cell number- and time-dependent manner, while Fluc activity in the cells increased with the cell number but not with time. The Lumina Imaging system showed that Gluc-Fluc was successfully expressed in MB49 bladder cells and cell lines with stable Gluc-Fluc expression were obtained after G418 selection., Conclusion: Gluc in the dual luciferase plasmid retains its expression characteristics. Due to the advantages of Fluc in localization in living imaging and the easy quantitative detection of Gluc, the dual luciferase plasmid, after transfection in MB49 bladder cells, allows reliable and dynamic detection of tumor growth in animal models.

Objective: To compare different methods commonly used for titering adenovirus and analyze the advantages and limitations of each method., Methods: Four recombined adenoviruses (Ad-G-AT2R-EGFP, Ad-CMV-EGFP, Ad-mif-shRNA-EGFP and Ad-CBA-GFP) were amplified and purified, and each was titered by optical absorbance, real-time PCR, green fluorescent protein (GFP)-labeled method, immunoassay, and cytopathic effect (CPE). The results were then comparatively analyzed., Results: No significant difference was found in the titer amounts derived from GFP-labeled method, immunoassay, and cytopathic effect method (P>0.1). A positive correlation was noted in the titer amounts determined by real-time PCR and immunoassay (r=0.965), even though the value (vg/ml) obtained by real-time PCR was 10 times higher than that by immunoassay (ifu/ml)., Conclusion: GFP-labeled method and immunoassay allow rapid determination of the adenoviral titer. Real-time PCR can not directly determine the real infectious titer of the adenovirus, but the result is well correlated to that of immunoassay and reflects, though indirectly, the actual infectious titer of adenovirus. Considering the procedural convenience and shorter time consumption, real-time PCR is still a practical method for adenoviral titration.

Objective: To construct human renal cell carcinoma patient-specific full-length antibody library using mammalian cell surface display technique., Methods: Peripheral blood mononuclear cells (PBMC) were isolated from patients with renal cell carcinoma. The repertoires of kappa light chain (LCkappa) and heavy chain variable region (VH) of antibody were amplified by RT-PCR. The LCkappa and VH libraries were inserted into the vector pDGB-HC-TM separately, and the ligated libraries were transformed into competent E.coli TOPO10 to construct the renal cell carcinoma patient-specific antibody heavy and light chain libraries. 293T cells were co-transfected with the libraries and the full-length human antibodies expressed on the surface of 293T cells were analyzed by flow cytometry., Results: The libraries of renal cell carcinoma-specific antibody kappa light chain (LCkappa) and heavy chain (IgG1) were constructed. The expression of the full-length human antibodies on the surface of 293T cell was confirmed by flow cytometry. The libraries showed an expressible combinatory diversity of 7.5x10(10)., Conclusion: The expressible antibody library provides a useful platform for screening of renal cell carcinoma-specific antibodies.