The ecological toxicity of cadmium (Cd, 10 mg kg−1 of dry weight soil) and butachlor (10, 50 and100 mg kg−1 of dry weight soil) in both their single and combined effects on soil urease and phosphatase was studied after 1, 3, 7, 14,
21 and 28 days exposure under controlled conditions in paddy and phaeozem soils. The results showed that Cd reduced the activities
of urease and phosphatase at early incubation time (1–7 days), while the reduction almost disappeared at the end of the incubation.
The effect of Cd on phosphatase was more pronounced than that on urease. The activities of urease and phosphatase were reduced
by butachlor, while urease activity was significantly (P < 0.05 or P < 0.01) improved when the concentrations of butachlor were 10 and 50 mg kg−1 at the end of the incubation. When Cd (10 mg kg−1) was combined with butachlor (50 and 100 mg kg−1), the activities of urease and phosphatase became lower than without combination at early incubation time, which indicated
that the toxicity of Cd significantly increased (P < 0.05 or P < 0.01). However, when Cd (10 mg kg−1) was combined with butachlor (10 mg kg−1), the activities of urease and phosphatase became higher than those without combination at the end of the incubation, which
indicated that the toxicity of Cd decreased. It was indicated that the combined effects depended largely on the incubation
time and the concentration ratio of Cd and butachlor. In addition, it was showed that the combined effects of butachlor and
Cd appeared different in paddy from phaeozem, which may be related to the different properties of these soils. 相似文献
Ongoing, rapid urban growth accompanied by habitat fragmentation and loss challenges biodiversity conservation and leads to decreases in ecosystem services. Application of the concept of ecological networks in the preservation and restoration of connections among isolated patches of natural areas is a powerful conservation strategy. However, previous approaches often failed to objectively consider the impacts of complex 3-D city environments on ecological niches. We used airborne lidar-derived information on the 3-D structure of the built environment and vegetation and detailed land use and cover data to characterize habitat quality, niche diversity, and human disturbance and to predict habitat connectivity among 38 identified habitat core areas (HCAs) in Nanjing, China. We used circuit theory and Linkage Mapper to create a landscape resistance layer, simulate habitat connectivity, and identify and prioritize important corridors. We mapped 64 links by using current flow centrality to evaluate each HCA's contribution and the links that facilitate intact connectivity. Values were highest for HCA links located in the west, south, and northeast of the study area, where natural forests with complex 3-D structures predominate. Two smaller HCA areas had high centrality scores relative to their extents, which means they could act as important stepping stones in connectivity planning. The mapped pinch-point regions had narrow and fragile links among the HCAs, suggesting they require special protection. The barriers with the highest impact scores were mainly located at the HCA connections to Purple Mountain and, based on these high scores, are more likely to indicate important locations that can be restored to improve potential connections. Our novel framework allowed us to sufficiently convey spatially explicit information to identify targets for habitat restoration and potential pathways for species movement and dispersal. Such information is critical for assessing existing or potential habitats and corridors and developing strategic plans to balance habitat conservation and other land uses based on scientifically informed connectivity planning and implementation. 相似文献
Vibrio bacteria live in both marine and freshwater habitats and are associated with aquatic animals. Vibrio vulnificus is a pathogenic bacterium that infects people and livestock. It is usually found in offshore waters or within fish and shellfish. This study presents a comparative proteomic analysis of the outer membrane protein (OMP) changes in V. vulnificus proteins after stimulation with sewage from sewage drains. Using two-dimensional electrophoresis followed by MALDI-TOF MS/MS, 32 protein spots with significant differences in abundance were identified and characterized. These identified proteins were found to be involved in various functional categories, including catalysis, transport, membrane proteins progresses, receptor activity, energy metabolism, cytokine activity, and protein metabolism. The mRNA expression levels of 12 differential proteins were further assessed by qRT-PCR. Seven genes including carboxypeptidase, hemoglobin receptor, succinate dehydrogenase iron-sulfur subunit, ATP synthase subunit alpha, thioredoxin, succinyl-CoA synthetase subunit, and alanine dehydrogenase were downregulated upon stimulation, whereas the protein expression levels HupA receptor, type I secretion outer membrane protein, glutamine synthetase, superoxide dismutase, OmpU, and VuuA were upregulated. 1H NMR spectra showed 18 dysregulated metabolites from V. vulnificus after the sewage stimulation and the pathogenicity was enhanced after that.