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41.
The present study was designed to examine the effects of cell-cycle synchronization protocols, such as confluent, roscovitine treatment and serum starvation, in bovine foetal fibroblasts on synchronization accuracy at G0/G1, viability, apoptosis, necrosis and ploidy for use as a nuclei donor. The cells in 5-10 passages were randomly allocated into three treated groups. Cells were cultured either in Dulbecco's modified Eagle's medium (DMEM) + 10% foetal bovine serum (FBS) until 90% confluent (group 1, confluent), in DMEM + 10% FBS + 30 microM roscovitine for 12 h (group 2, roscovitine), or in DMEM + 0.5% FBS for 5 days (group 3, serum starvation). Most of the cells (>80%) in all groups were arrested at the G0/G1 stage. Although the rates did not differ, cells in group 1 showed an increased cell population arrested at the G0/G1 phase. Significantly (p < 0.05) higher rates of apoptosis occurred in group 3 than in group 1 and 2 (10% vs 6% and 6%, respectively). No differences in chromosomal abnormality were observed among groups. However, by increasing the number of cell culture passages up to 15, significantly (p < 0.05) higher chromosomal abnormality was observed than in 5 and 10 passages (39% vs 28% and 23%, respectively) in group 1. The results clearly indicated that bovine foetal fibroblasts could be effectively synchronized at G0/G1 stages by all the three different treatments, confluent, roscovitine and serum starvation. However, cells in confluent showed reduced apoptosis and necrosis when they underwent 5-10 passages, exhibiting increased percentage of cells with stable chromosome diversity. Hence, cells in confluent merit further studies before they could be used as nuclear donors.  相似文献   
42.

Context

The study of ecosystem services has extended its influence into spatial planning and landscape ecology, the integration of which can offer an opportunity to enhance the saliency, credibility, and legitimacy of landscape ecology in spatial planning issues.

Objectives

This paper presents a conceptual framework suitable for spatial planning in human dominated environments supported by landscape ecological thinking. It seeks to facilitate the integration of ecosystem services into current practice, including landscape metrics as suitable indicators.

Methods

A literature review supported the revision of existing open questions pertaining to ecosystem services as well as their integration into landscape ecology and spatial planning. A posterior reflection of the current state-of-the-art was then used as a basis for developing the spatial planning conceptual framework.

Results and conclusion

The framework is articulated around four phases (characterisation, assessment, design, and monitoring) and three concepts (character, service, and value). It advocates integration of public participation, consideration of “landscape services”, the inclusion of ecosystem disservices, and the use of landscape metrics for qualitative assessment of services. As a result, the framework looks to enhance spatial planning practice by providing: (i) a better consideration of landscape configuration in the supply of services (ii) the integration of anthropogenic services with ecosystem services; (iii) the consideration of costs derived from ecosystems (e.g. disservices); and (iv) an aid to the understanding of ecosystem services terminology for spatial planning professionals and decision makers.
  相似文献   
43.
44.
Foal septicemia is a major cause of neonatal morbidity and mortality. In order to improve success rates, earlier diagnosis and treatment are essential. This article stresses methods to prevent and treat infections in the compromised equine neonate.  相似文献   
45.
46.
Corn kernels and young corn plants (Zea mays) growing beneath and close to a 6-yr old galvanized steel tower supporting a 500-kV electrical transmission line had elevated concentrations of Zn due to corrosion of the protective Zn coating on the steel. Zinc corrodes preferentially from galvanized steel and as a result, protects the underlying metal from rusting (sacrificial protection). Corn plants growing beneath and close to towers absorb Zn from soil contaminated by runoff from the lattice towers and from falling water droplets. Corn seedlings (7-wk old) grown in highly contaminated soil (1425 ± 264 μ g?1) collected near a 30-yr old tower had much higher concentrations of Zn than did plants (8-wk old) growing near and under the 6-yr old tower. The concentrations of Zn found in plants were not high enough to be hazardous to domestic animals and contamination of soil was localised around the towers studied. Cd does not appear to be accumulating in soils or plants near the towers.  相似文献   
47.
Control of mRNA decay by heat shock-ubiquitin-proteasome pathway   总被引:1,自引:0,他引:1  
Cytokine and proto-oncogene messenger RNAs (mRNAs) are rapidly degraded through AU-rich elements in the 3' untranslated region. Rapid decay involves AU-rich binding protein AUF1, which complexes with heat shock proteins hsc70-hsp70, translation initiation factor eIF4G, and poly(A) binding protein. AU-rich mRNA decay is associated with displacement of eIF4G from AUF1, ubiquitination of AUF1, and degradation of AUF1 by proteasomes. Induction of hsp70 by heat shock, down-regulation of the ubiquitin-proteasome network, or inactivation of ubiquitinating enzyme E1 all result in hsp70 sequestration of AUF1 in the perinucleus-nucleus, and all three processes block decay of AU-rich mRNAs and AUF1 protein. These results link the rapid degradation of cytokine mRNAs to the ubiquitin-proteasome pathway.  相似文献   
48.
The Modular Modeling System (MMS) is an integrated system of computer software that is being developed to provide the research and operational framework needed to support development, testing, and evaluation of physical-process algorithms, and to facilitate integration of user-selected sets of algorithms into operational physical-process models. MMS uses a module library that contains compatible modules for simulating a variety of water, energy, and biogeochemical processes. A model is created by selectively linking modules from the library using MMS model-building tools. A geographic information system (GIS) interface also is being developed for MMS to support a variety of GIS tools for use in characterizing and parameterizing topographic, hydrologic, and ecosystem features, visualizing spatially and temporally distributed model parameters and variables, and analyzing and validating model results. MMS is being coupled with the Power Reservoir System Model (PRSYM) to provide a database-centered decision support system for making complex operational decisions on multipurpose reservoir systems and watersheds. The U.S. Geological Survey and the Bureau of Reclamation are working collaboratively on a project titled the Watershed Modeling Systems Initiative to develop and apply the coupled MMS — PRSYM models to the San Juan River basin in Colorado, New Mexico, Arizona, and Utah.  相似文献   
49.
Reef fish are critical in maintaining the ecological function of coral reefs and providing food security for coastal communities in developing countries. Reef fishery stocks are under increasing threat from factors such as climate-related habitat degradation, land use practices, and resource extraction related to human population growth, direct consumption and increasing connectivity between the in situ fishery and fish markets. This study investigates how reef fish stocks are related to environmental, localised resource use and market proximity indicators across 51 sites in the Solomon Islands. Hard coral cover is the best indicator of total target fishery biomass, with cover of less than around 31% associated with significantly less biomass than sites with higher coral cover. Direct resource use indicators such as fish consumption and fish sale pressure were poor predictors of target fish biomass. Distance of the fishery resource from community, provincial sub-station, provincial capital and national capital are all significantly and positively correlated with biomass for four key fishery families: Acanthuridae (surgeonfish), Scaridae (parrotfish), Lethrinidae (emperor), Lutjanidae (snapper). Multiple spatial scale relationships are evident between market proximity indicators and Lutjanidae and Scaridae families. Thus, while pooled target fishery biomass is constrained by environment, analysis at fishery family resolution reveals the effects of anthropogenic impact through market proximity on constraining fishery biomass distribution in the Solomon Islands. This study highlights the need for reef fishery managers and conservation practitioners to focus attention on proximity of resources to markets to sustain the ecological health of reef dominated ecosystems.  相似文献   
50.
Observations made in summer 1981 show a significant and widespread decrease in salinity, averaging 0.02 per mil, in deep waters of the subpolar North Atlantic over the past two decades. This implies a relatively rapid response of deep water formation to climatic perturbation.  相似文献   
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