This article establishes a set of indicators and standards for landscape ecological sensitivity analysis of site resources by using the theories and approaches of landscape ecology. It uses landscape diversity index(H...This article establishes a set of indicators and standards for landscape ecological sensitivity analysis of site resources by using the theories and approaches of landscape ecology. It uses landscape diversity index(H), evenness(E), natural degree(N), contrast degree(C) to study spatial structure and landscape heterogeneity of site resources and thus provides a qualitative-quantitative evaluation method for land planning and management of small, medium scale areas. The analysis of Yantian District, Shenzhen of China showed that Wutong Mountain belonged to high landscape ecological sensitivity area, Sanzhoutian Reservoir and Shangping Reservoir were medium landscape sensitivity area and high ecological sensitivity area; Dameisha and Xiaomeisha belonged to medium sensitivity area caused by the decline of natural ecological areas. Shatoujiao, Yantian Pier belonged to low sensitivity area but urban landscape ecological development had reshaped and influenced their landscape ecological roles in a great extent. Suggestions on planning, protection goals and development intensity of each site or district were raised.展开更多
Manipulation of mouse genome has merged as one of the most important approaches for studying genefunction and establishing the disease model because of the high homology between human genome and mouse genome. In this ...Manipulation of mouse genome has merged as one of the most important approaches for studying genefunction and establishing the disease model because of the high homology between human genome and mouse genome. In this study, the chemical mutagen ethylnitrosourea (ENU) was employed for inducing germ cell mutations in maleC57BL/6J mice. The first generation (G1) of the backcrossof these mutated mice, totally 3172, was screened for abnor-mal phenotypes on gross morphology, behavior, learning and memory, auditory brainstem response (ABR), electrocardio-gram (ECG), electroretinogram (ERG), flash-visual evoked potential (F-VEP), bone mineral density, and blood sugarlevel. 595 mice have been identified with specific dominantabnormalities. Fur color changes, eye defects and hearing loss occurred at the highest frequency. Abnormalities related to metabolism alteration are least frequent. Interestingly, eye defects displayed significant left-right asymmetry and sexpreference. Sex preference is also observed in mice with ab-normal bone mineral density. Among 104 G1 generation mutant mice examined for inheritability, 14 of them have been confirmed for passing abnormal phenotypes to their progenies. However, we did not observe behavior abnormali-ties of G1 mice to be inheritable, suggesting multi-gene con-trol for these complicated functions in mice. In conclusion, the generation of these mutants paves the way for under-standing molecular and cellular mechanisms of these ab-normal phenotypes, and accelerates the cloning of disease-related genes.展开更多
文摘This article establishes a set of indicators and standards for landscape ecological sensitivity analysis of site resources by using the theories and approaches of landscape ecology. It uses landscape diversity index(H), evenness(E), natural degree(N), contrast degree(C) to study spatial structure and landscape heterogeneity of site resources and thus provides a qualitative-quantitative evaluation method for land planning and management of small, medium scale areas. The analysis of Yantian District, Shenzhen of China showed that Wutong Mountain belonged to high landscape ecological sensitivity area, Sanzhoutian Reservoir and Shangping Reservoir were medium landscape sensitivity area and high ecological sensitivity area; Dameisha and Xiaomeisha belonged to medium sensitivity area caused by the decline of natural ecological areas. Shatoujiao, Yantian Pier belonged to low sensitivity area but urban landscape ecological development had reshaped and influenced their landscape ecological roles in a great extent. Suggestions on planning, protection goals and development intensity of each site or district were raised.
基金supported by the State“863”High-Tech Project and the National Gongguan Project
文摘Manipulation of mouse genome has merged as one of the most important approaches for studying genefunction and establishing the disease model because of the high homology between human genome and mouse genome. In this study, the chemical mutagen ethylnitrosourea (ENU) was employed for inducing germ cell mutations in maleC57BL/6J mice. The first generation (G1) of the backcrossof these mutated mice, totally 3172, was screened for abnor-mal phenotypes on gross morphology, behavior, learning and memory, auditory brainstem response (ABR), electrocardio-gram (ECG), electroretinogram (ERG), flash-visual evoked potential (F-VEP), bone mineral density, and blood sugarlevel. 595 mice have been identified with specific dominantabnormalities. Fur color changes, eye defects and hearing loss occurred at the highest frequency. Abnormalities related to metabolism alteration are least frequent. Interestingly, eye defects displayed significant left-right asymmetry and sexpreference. Sex preference is also observed in mice with ab-normal bone mineral density. Among 104 G1 generation mutant mice examined for inheritability, 14 of them have been confirmed for passing abnormal phenotypes to their progenies. However, we did not observe behavior abnormali-ties of G1 mice to be inheritable, suggesting multi-gene con-trol for these complicated functions in mice. In conclusion, the generation of these mutants paves the way for under-standing molecular and cellular mechanisms of these ab-normal phenotypes, and accelerates the cloning of disease-related genes.
