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1.
Despite widely acknowledged handicaps of the species approach to identifying priority conservation areas, many workers continue to use these flawed techniques as the backbone of their analyses. Species-based approaches address only a small part of biological diversity by ignoring different levels of organisation as well as the functional linkages among these levels. These data are often biased and incomplete and are often used in preference to data dealing with higher biological levels of organisation though the latter may be readily available. Within the framework of Noss's [(1990) Conservation Biology 4: 355–364] hierarchical definition of biodiversity (and Scott etal. [(1993) Wildlife Monographs 123: 1–31] gap analysis), we propose a top-down model dealing with broad organisational levels first, and finer-scale species distributions last. Note that we do not discard the latter approach, but merely argue for its use at a stage when, in our opinion, it adds most to the value of the prioritisation exercise. The model is flexible so that additional information, particularly those related to threats to biological diversity, can be added when they are available.  相似文献   

2.
What criteria should be used to select biodiversity indicators?   总被引:2,自引:0,他引:2  
The conservation of biodiversity is a major goal in nature conservation, but measuring the total biodiversity of a site or a region is not possible; thus there is a great demand for indicators to represent biodiversity. To be able to make use of indicators, criteria must first be established for their selection, and the degree to which the indicators meet the criteria must be tested. However, the purposes for which indicators are applied—and thus sometimes the criteria themselves—differ between ecological science and environmental policy. As transparency in choosing and testing suitable biodiversity indicators will optimize the results of an indicator, this article first aims to determine if there are common approaches in selecting biodiversity indicators in ecology and environmental policy. Second, we asked which criteria biodiversity indicators were scientifically tested against to determine their suitability. To answer these questions, we analyzed papers on biodiversity indicators referenced in the Web of Science. Our results demonstrate different patterns for selecting biodiversity indicators in the different fields of application. In ecology, the quality of indicators is mainly determined by a close relationship between indicator and indicandum (i.e., indicated phenomenon), while the relevance of an indicator for a given issue, e.g., reserve selection or an assessment of a certain impact, is of paramount importance for conservation policy. Surprisingly, few biodiversity indicators are empirically tested to determine if they meet the criteria by which they were purportedly chosen. We argue that this is due to the different conceptualizations of biodiversity indicators in science and environmental policy. Since the suitability of biodiversity indicators remains untested in many cases, our findings suggest room to make better use of indicators in ecology and environmental policy. As the results of ecological research are put to use to solve environmental problems, the selection of indicators for ecological research should correspond to a large extent with those used in environmental policy. Further, to assess the suitability of a biodiversity indicator, it should be tested against all of the criteria relevant for its selection.  相似文献   

3.
Malaria is a mosquito-borne infectious disease caused by Plasmodium parasites transmitted by the infectious bite of Anopheles mosquitoes. Vector control of malaria has predominantly focused on targeting the adult mosquito through insecticides and bed nets. However, current vector control methods are often not sustainable for long periods so alternative methods are needed. A novel biocontrol approach for mosquito-borne diseases has recently been proposed, it uses maternally inherited endosymbiotic Wolbachia bacteria transinfected into mosquitoes in order to interfere with pathogen transmission. Transinfected Wolbachia strains in Aedes aegypti mosquitoes, the primary vector of dengue fever, directly inhibit pathogen replication, including Plasmodium gallinaceum, and also affect mosquito reproduction to allow Wolbachia to spread through mosquito populations. In addition, transient Wolbachia infections in Anopheles gambiae significantly reduce Plasmodium levels. Here we review the prospects of using a Wolbachia-based approach to reduce human malaria transmission through transinfection of Anopheles mosquitoes.  相似文献   

4.
5.

Background  

The stimulation of nerve or cortical tissue by magnetic induction is a relatively new tool for the non-invasive study of the brain and nervous system. Transcranial magnetic stimulation (TMS), for example, has been used for the functional mapping of the motor cortex and may have potential for treating a variety of brain disorders.  相似文献   

6.
Tony Y. Hu 《Proteomics》2016,16(13):1947-1948
Comparative proteomics is increasingly used to detect biomarkers and therapeutic targets that differ between healthy and diseased populations; however, differences in posttranslational modifications have received less attention. In this issue, Yang et al. (Proteomics 2016, 16, 1872–1880) present data indicating that a glycoproteomics approach can detect N‐glycosylated membrane protein differences between non‐HIV‐infected and latently infected human CD4+ T‐cell lines, identifying 172 proteins differentially expressed by these cells. Latently infected CD4+ T cells are thought to represent the major barrier to eventual HIV cure, but do not express detectable levels of viral protein and have not been shown to express biomarkers that can distinguish them from the vastly more abundant uninfected CD4+ T‐cell population. The findings of Yang et al. suggest that glycoproteomic analyses may have untapped potential to identify novel biomarkers and therapeutic targets in cell populations not readily distinguishable be standard proteomic analyses.  相似文献   

7.
Can ecological theory be used to improve water quality?   总被引:6,自引:0,他引:6  
Maciej Gliwicz  Z. 《Hydrobiologia》1992,243(1):283-291
The role of ecology in environmental management has been more to warn of the dangers of pollution than to propose technical solutions for environmental problems, this being mostly left to chemists and engineers. Only limited aspects of the broad and diverse theory of ecology have been applied in the present bottom-up-control approach to water management (nutrient reduction). Another aspect of ecological theory which has recently become applicable is the top-down-control approach known as biomanipulation (promoting efficient herbivores). Both approaches are likely to be reinforced in the future by further application of ecological theory to water management. Of the multiple possibilities of applying ecological theory to environmental problems, one is the use of our knowledge on chemical communication in aquatic habitats, the phenomena by which prey detect the presence of their predators. I postulate that the phytoplankton standing crop might be reduced by chemical regulation of the physiology and life cycles of algae and cyanobacteria, as well as by chemical regulation of the behaviour and life histories of planktonic herbivores and their predators. At present planktivorous fish seem to be the most logical target for such chemical manipulation. A desirable effect, i.e. a reduction in algal standing crop, could be achieved by scaring fish from the lake pelagial thus releasing predation pressure on the offshore herbivorous zooplankton.  相似文献   

8.
Can ribozymes be used to regulate procaryote gene expression?   总被引:3,自引:0,他引:3  
The in vivo activity of ribozymes designed against mRNA coding for E. coli beta-galactosidase was tested both in intramolecular and in intermolecular conditions. When recombinant M13 phage DNA carrying on the same molecule the information for both the ribozyme and the target was transfected into bacterial cells, ribozyme activity was observed. Conversely, a ribozyme coded by a recombinant M13 vector, but targeted against an mRNA transcribed from the F episome including the remaining part of the beta-galactosidase gene, was inefficient.  相似文献   

9.
Instrumented treadmills offer significant advantages for analysis of human locomotion, including recording consecutive steady-state gait cycles, precisely controlling walking speed, and avoiding force plate targeting. However, some studies of hemiparetic walking on a treadmill have suggested that the moving treadmill belt may fundamentally alter propulsion mechanics. Any differences in propulsion mechanics during treadmill walking would be problematic since recent studies assessing propulsion have provided fundamental insight into hemiparetic walking. The purpose of this study was to test the hypothesis that there would be no difference in the generation of anterior/posterior (A/P) propulsion by performing a carefully controlled comparison of the A/P ground reaction forces (GRFs) and impulses in healthy adults during treadmill and overground walking. Gait data were collected from eight subjects walking overground and on a treadmill with speed and cadence controlled. Peak negative and positive horizontal GRFs in early and late stance, respectively, were reduced by less than 5% of body weight (p<0.05) during treadmill walking compared to overground walking. The magnitude of the braking impulse was similarly lower (p<0.05) during treadmill walking, but no significant difference was found between propulsion impulses. While there were some subtle differences in A/P GRFs between overground and treadmill walking, these results suggest there is no fundamental difference in propulsion mechanics. We conclude that treadmill walking can be used to investigate propulsion generation in healthy and by implication clinical populations.  相似文献   

10.

Background  

Mass spectrometry and proteomic analyses have become powerful tools for the analysis of proteins and peptides. Investigation of proteins contained in the various layers of the avian eggshell has focused entirely on domesticated species. It has been widely assumed that this existing research can inform the study of wild bird species despite the fact that the vast majority of the diversity in avian species (~95%) exists outside the Orders to which domestic and poultry species belong. Museum collections offer a potentially valuable source of material for studying composition of wild avian eggshell matrix proteins. We used museum and fresh eggshells of common quails Coturnix coturnix to compare the protein composition of their organic matrices. Four eggs of domestic chickens were analysed simultaneously as a control for comparison to the fresh and museum quail eggs. The determination of the proteins was carried out using enzymatic cleavage followed by high-performance mass spectrometry.  相似文献   

11.
The effect of mobility on 15N chemical shift/15N–1H dipolar coupling (PISEMA) solid state NMR experiments applied to macroscopically oriented β-barrels is assessed using molecular dynamics simulation data of the NalP autotransporter domain embedded in a DMPC bilayer. In agreement with previous findings for α-helices, the fast librational motion of the peptide planes is found to have a considerable effect on the calculated PISEMA spectra. In addition, the dependence of the chemical shift anisotropy (CSA) and dipolar coupling parameters on the calculated spectra is evaluated specifically for the β-barrel case. It is found that the precise choice of the value of the CSA parameters σ1122 and σ33 has only a minor effect, whereas the choice of the CSA parameter θ shifts the position of the peaks by up to 20 ppm and changes the overall shape of the spectrum significantly. As was found for α-helices, the choice of the NH bond distance has a large effect on the dipolar coupling constant used for the calculations. Overall, it is found that the alternating β-strands in the barrel occupy distinct regions of the PISEMA spectra, forming patterns which may prove useful in peak assignment.Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s10858-005-5094-5  相似文献   

12.
International legislation demands that statutory bodies report on the health of aquatic ecosystems. Traditionally, ecosystem components have been characterised according to species assemblages but with limited success in predicting health. On the other hand, many studies based upon functional groupings that include trophic relationships and bioturbation potential have shown response to pollution. However, these and other functional group responses have not yet been linked to broad scale physical variables. To date this has hindered the development of a predictive model of function based on abiotic factors. In addition, most functional studies ignore any potential role of body size when assessing the importance of each species to overall functional group measures. By weighting all species that belong to the same guild equally, the investigator risks overestimating the true importance of any one guild to the environment. This study compared the ability of different functional group approaches to discriminate between separate estuarine sites, whilst linking biotic data with abiotic factors. Using data for the Tamar Estuary, we show that no two methods of classifying the biotic data, according to function, produce the same groupings of sites; nor did any method produce groupings that matched clusters based on abiotic factors alone. Instead, results show that not only can choice of functional method alter our perception of site associations but also, can influence the strength of similarity relationships between abiotic and biotic datasets. Both the use of bioturbation measures and weighting species abundance data by body size provided better relationships between biotic and abiotic data than the use of trophic groups. Thus both methods merit further research to produce algorithms for modelling studies.  相似文献   

13.
Species traits which facilitate introduction and predominance have been quantitatively ranked using interval arithmetic to search for common patterns among 113 marine macroalgae introduced in Europe. Three main categories were used: dispersal, establishment and ecological impact. These were further subdivided into more specific categories, a total of 13. Introduced species were compared with the same number of native species randomized from the same families as the introduced. Invasive species (i.e. species having a negative ecological or economical impact) were also compared with non-invasive introductions, separately for the three algal groups. In many categories, as well as when adding all species, the introduced species ranked more hazardous than the native species and the invasive species ranked higher than the non-invasive ones. The ranking within the three main categories differed, reflecting different strategies between the species within the three algal groups. When all categories (excluding salinity and temperature) were summed, the top five risk species, all invasive, were, in descending order, Codium fragile spp.tomentosoides, Caulerpa taxifolia, Undaria pinnatifida, Asparagopsis armata and Grateloupia doryphora, while Sargassum muticum ranked eight and Caulerpa racemosa ten. Fifteen of the twenty-six species listed as invasive were among the twenty highest ranked.  相似文献   

14.
Patient adherence to treatment is an important factor in the effectiveness of antiretroviral regimens. Adherence to treatment could be monitored by estimation of antiretroviral drugs in biological fluids. We aimed to obtain information on the quantity and duration of excretion of lamivudine in urine following oral administration of a single dose of 300 mg and to assess its suitability for adherence monitoring purposes. Spot urine samples were collected before dosing and at 4, 8, 12, 24, 28, 32, 48, 72, and 96 hours post dosing from 10 healthy subjects, and lamivudine was estimated by high-pressure liquid chromatography (HPLC). Lamivudine values were expressed as a ratio of urine creatinine. About 91% of the ingested drug was excreted by 24 hours, and the concentration thereafter in urine was very negligible. A lamivudine value of 0.035 mg/mg creatinine or less at 48 hours is suggestive of a missed dose in the last 24 hours. The study findings showed that estimation of urine lamivudine in spot specimens could be useful in monitoring patient adherence to antiretroviral treatment. However, this needs to be confirmed on a larger sample size and among patients on once-daily and twice-daily treatment regimens.  相似文献   

15.
16.
17.
In recent years, there has been increasing interest in modelling of species abundance data in addition to presence data. In this study, we assessed the similarities and differences between presence‐absence distributions and abundance distributions along similar environmental gradients, derived, respectively, from presence‐absence and abundance data. Moreover, we examined the possibility of using presence‐absence distribution models to derive abundance distributions. For this purpose, we used Braun‐Blanquet abundance scores for 243 vascular species at 10 996 French forest sites. Species distribution models were used to analyse the link between the patterns of occurrence, low abundance and high abundance for each species with regard to mean annual temperature, June water balance, and soil pH. For each species, differences in the modelled distributions were characterised by the ecological optimum and ecological amplitude. A comparison of the presence‐absence and abundance distributions for all species revealed similar optima and different amplitudes along the three ecological factors. An abundant‐centre distribution was observed in environmental space, with species abundance being greatest at the optimal conditions and lower at less favourable conditions of the species occurrence response. Geographical habitat mapping also shows centred, high‐abundance suitability within the presence habitat of each species. We conclude that species distribution models derived from presence‐absence data provide useful information about the ecological optima of abundance distributions but overestimate the range of habitats suitable for high species abundance. This study demonstrates the utility of presence‐absence data for ecologist and conservation biologist when they are interested in the optimal conditions of high species abundance.  相似文献   

18.
19.
We investigate the usefulness of higher taxa as surrogates for species richness and diversity of litter/soil insects. We use data for Coleoptera (beetles) and Formicidae (ants) collected during biodiversity surveys of five tropical and two temperate countries, and use Pearson’s product moment correlations to assess the surrogacy relationship. Our results suggest that genera would provide an adequate surrogate for species richness of Coleoptera, but not for Formicidae. We suggest that the usefulness of higher taxa as surrogates for richness is dependent on both taxonomy and scale. Higher taxa provided a poor surrogate for species diversity due to the added dimension of evenness of community structure, and we recommend that higher taxa should not be used as surrogates for species diversity.  相似文献   

20.
The quality of in vitro-produced bovine embryos remains variable. The selection of these embryos based only on their morphology does not allow for acceptable gestational rates to be obtained. The use of metabolic markers to select viable embryos before transfer would be of valuable help, both economically and as a research tool. The ideal marker should meet several conditions: it should be able to be evaluated 1) in a totally non-invasive manner, 2) on individual embryos (which necessitates very sensitive techniques), 3) very rapidly (so that it is compatible with the immediate transfer of fresh embryos), and 4) in order to allow viable embryos to be separated from those that are not viable, whatever the production system used. In practice, such a marker does not exist, but certain methods of metabolic evaluation resemble it. The development of a metabolic marker is confronted by the metabolic characteristics of the embryo, notably the evolution of the metabolism during the development of the embryo and its adaptation to the changes in the environment.  相似文献   

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