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1.
Society needs urgently good tools to understand the biosphere dynamics, become aware of Earth's biophysical limits and make appraisals of environmental performance of human dominated systems. In this context, the Ecological Footprint (EF) was suggested as one of the most important tools. But, according to calculations based on Emergy Analysis, the indicators of EF could underestimate the problem of human carrying support. EF does not consider the work of untouched nature in productivity and ecosystems services. In order to improve the EF results, the present study suggests: (a) to include the ecosystems not considered in conventional EF i.e. tundra, deserts and areas covered by ice; (b) to consider the value of Net Primary Production (NPP) in Emergy units (seJ m?2 year?1) as the base for the calculation of Equivalent Factors (EQF); (c) to account for the consumption of fossil energy used in collection, treatment and distribution of water for domestic use, for this the carbon emissions data (in tonC m?3 of water) were used. Introducing these changes to the conventional EF calculation and considering the Peruvian economy (in 2004) as the study case, the Biocapacity obtained was 14.31 gha capita?1 and the footprint was 6.68 gha capita?1. These values mean that Peru can support 2.14 times its population if the current life style is maintained, as opposed to the 4.0 times ratio obtained with a conventional EF calculation.  相似文献   

2.
In this paper, the authors made an attempt to measure appropriation of ecosystems more reasonably and effectively based on examining the advantages and disadvantages of emergy analysis and ecological footprint. By combining emergy analysis with ecological footprint (EF) in terms of spatial equivalent of energy productivity, a new method of solar space (SS) and its calculating framework was proposed, and some necessary parameters for this method of analysis were calculated. A case study was followed under this calculating framework for Yangzhou city, Jiangsu province, Eastern China, using the data of the year 2000. The main results are as follows: (1) The ecological space in Yangzhou city includes earth surface space and solar space, and their demands were bigger than their supply. In the year of 2000, the earth surface space had an absolute deficit of 2.3063E?02 Ga-ha per capita (global hectares), and the solar space had an absolute deficit of 1.4944E?04 Sa-ha per capita (solar hectares). (2) There was a relative ecological deficit of 3.68% in earth surface space, and that of 154.86% in solar space. (3) Only freshwater areas and built-up areas were in a state of surplus, and there was a relative ecological surplus of 82.66% for freshwater areas, being greater than that for built-up areas. (4) The ranking of absolute ecological deficit in a descending order was as follows: solar space > arable land > pasture > forest > marine area > garden land, while the relative ecological deficit was the following: solar space > pasture land > forest land > arable land > garden land, except marine areas.A qualitative comparison of methodology was made between solar space method and ecological footprint according to their capability to describe the temporal-spatial characteristics of ecosystems appropriation. Moreover, a quantitative comparison was also conducted to show their differences in applicability to the assessment of ecosystems appropriation. It was shown that the calculating results from solar space method were bigger than that from ecological footprint because the former supplemented additional items of appropriation omitted by the later and included some new items of indirect appropriation that were excluded by the later. It is found that the new measure of solar space operates well as an indicator of the city's appropriation to ecosystems.  相似文献   

3.
The ecological risk from over-population has been recognized since Malthus (1798). GDP growth per capita in agriculture disproved his pessimism but, since the Club of Rome and its case on Limits to Growth more recently there has been concern that there is a parallel risk from such growth in terms of ecological footprints (EF). Authors have developed a GDP/EF correlation function and calculated the ecological footprint (EF) from 10,000 B.C. till 1960, using historical statistics, with the method of backcasting (Brandes and Brooks, 2005).1 In all major indicators growth patterns have been dominating, not only since the industrial revolution, but in the known history of mankind. From data since 1961, we calculate the correlation between GDP and the ecological footprint and have been able to determine long time data series of population, GDP, biocapacity and EF. Our findings are first: the main driver of growth and environmental degradation is not population per se, but consumption patterns and levels multiplied by the number of consumers, especially in developed economies, as the I = PAT equation recognized (Ehrlich and Holdren, 1971). In fact, as we approach to today, population, which used to be the key driver to growth and environmental degradation, becomes the least important driver, especially in the last two decades. Second: change is not incremental or linear as assumed in much mainstream economics: in line with Schumpeter's bunching and swarming and it jumps and leaps asymmetrically, as in our finding of such a leap (the 7th) between the 1930s and 1970s. Third: the dominant paradigm legitimizing growth (from the late 18th century) while already challenged by many since the Club of Rome and other reports should be revisited in terms of the concept of ‘fullness’ in the sense that while the earth in 1776 was roughly 10 per cent full, by 2008 this figure was over 150 per cent.  相似文献   

4.
Foraging efficiency of Lysiphlebus fabarum Marshall, the most abundant and effective parasitoid of the black bean aphid, Aphis fabae Scopoli, in terms of functional and numerical responses and mutual interference, was studied on broad bean plants in a growth chamber at 21 °C, 70 ± 5% RH and a photoperiod of 16:8 (L:D) h. Using logistic regression, a type II functional response was determined for L. fabarum. Nonlinear least-square regression was used to estimate the searching efficiency (a') and handling time (Th). Numerical response of L. fabarum to cumulative host densities was partially linearly increasing. Nicholson's model and linear regression were used to determine the per capita searching efficiency and interference coefficient, respectively. In general, the per capita parasitism and, consequently, the per capita searching efficiency decreased significantly as parasitoid density increased. Mutual interference and quest constants were ? 0.508 and ? 0.697, respectively. The results of this study suggest that both the host and parasitoid densities have no significant impact on the progeny sex ratio. The information provided here will be useful in assessing the efficiency of L. fabarum as a biological control agent of A. fabae, devising mass-rearing protocols and implementing release programs for this parasitoid.  相似文献   

5.
Construction activity is now a major consumer of natural resources. As a general rule, resource consumption has been evaluated through methodologies related to Life Cycle Analysis. This research is proposed to integrate the Ecological Footprint indicator into the building sector: to observe the difficulties and the benefits it can generate relative to other indicators. To this end, prior knowledge related to the Ecological Footprint indicator must first be adapted to the residential sector, by analyzing the construction of buildings, and secondly a calculation methodology is established in order to quantitatively determine what impacts are generated by industry according to the Ecological Footprint indicator. This methodology applies the indicator to resources used (energy, water, labour, construction materials, etc.) and to waste generated in the construction of residential buildings.The methodology is applied to a case study corresponding to the urbanization and building construction of a representative building type in Andalusia (Spain) when the building is in the planning stage. The final result is 0.384 gha/year/m2.  相似文献   

6.
Globally human pressure on the biosphere is increasing, in spite of increases in land use efficiency. The pressure consists of land use and potential degradation. Human appropriation of net primary production (HANPP) is emerging as an indicator, which combines the dual aspects of biomass use and land degradation. Recently HANPP has been used to map the increasing dependence of European countries on biomass imports and the conflicting processes of increased yields and increased consumption. However large overview studies could be complemented with indepth analysis into the causes of changes in individual countries and economic sectors. This allows the analysis of the macroeconomic drivers of change and the responses in sectors to these drivers. In this study we decomposed the HANPP of Finland including imports for the years 2000–2010 using IPAT and applied input-output analysis to look at sectoral land use efficiency in that time period. Finland is a country with intensive biomass trade, and with a very high per capita HANPP. During the study period the sum of domestic and embodied in imports HANPP of the Finnish economy decreased from 76 Mt C/a to 62 Mt C/a (−1% annually on average), while the HANPP related to imports increased from 12 Mt C/a to 14 Mt C/a. The overall trend was that of declining exports and increasing domestic consumption. Of the economic sectors wood harvesting and processing dominated HANPP results, followed by residential construction, animal production and energy supply. In terms of HANPP, most of these decreased, but housing and energy production increased considerably from 2002 to 2010. At the macroeconomic level domestic biomass use per unit of value added decreased (−2.2%/a) as did the amount of HANPP per unit of biomass (−1.1%/a) reflecting increased economic efficiency in land use. In contrast, GDP/capita (+1.3%/a), population (+0.4%) and the share of outsourced HANPP (+0.6%) resulted in increased consumption-based HANPP (from 21 Mt C in 2002 to 27 Mt C in 2010). Our results underline the importance of including international trade and consumption in interpreting overall change in regional HANPP.  相似文献   

7.
Cyclestheria hislopi is thought to be the only extant species of Cyclestherida. It is the sister taxon of all Cladocera and displays morphological characteristics intermediate of Spinicaudata and Cladocera. Using one mitochondrial (COI) and two nuclear (EF1α and 28S rRNA) markers, we tested the hypothesis that C. hislopi represents a single circumtropic species. South American (French Guiana), Asian (India, Indonesia, Singapore) and several Australian populations were included in our investigation. Phylogenetic and genetic distance analyses revealed remarkable intercontinental genetic differentiation (uncorrected p-distances COI > 13%, EF1α > 3% and 28S > 4%). Each continent was found to have at least one distinct Cyclestheria species, with Australia boasting four distinct main lineages which may be attributed to two to three species. The divergence of these species (constituting crown group Cyclestherida) was, on the basis of phylogenetic analyses of COI and EF1α combined with molecular clock estimates using several fossil branchiopod calibration points or a COI substitution rate of 1.4% per million years, dated to the Cretaceous. This was when the South American lineage split from the Asian–Australian lineage, with the latter diverging further in the Paleogene. Today’s circumtropic distribution of Cyclestheria may be best explained by a combination of Gondwana vicariance and later dispersal across Asia and Australia when the tectonic plates of the two continents drew closer in the early Miocene. The lack of morphological differentiation that has taken place in this taxon over such a long evolutionary period contrasts with the high level of differentiation and diversification observed in its sister taxon the Cladocera. Further insights into the evolution of Cyclestheria may help us to understand the evolutionary success of the Cladocera.  相似文献   

8.
The Ansell's mole-rat (Fukomys anselli, Bathyergidae) is a small-sized social subterranean rodent whose distribution is confined to the Lusaka area in Zambia. It is an established model species for various laboratory studies, but until now the knowledge of its biology under natural conditions has been limited. Here, we provide the first comprehensive natural history and ecological data on a free living population from Miombo woodland. The Ansell's mole-rat lives in groups of up to 13 individuals (mean 9.7 ± 2.5; N = 9 complete, fully established family groups) with a single breeding pair per group. The family groups occupy very large and complex burrow systems consisting of 0.5–2.8 km of tunnels (mean = 1.2 ± 0.6 km, N = 15), which are densely branched and reticulated especially around nests. Burrow systems of neighbouring family groups were often interconnected by a freely passable tunnel, which has never before been documented in any African mole-rats. Mole-rat food density in the study area was relatively low (10.0 ± 8.4 m?2) but its biomass was large (457 ± 889 g m?2). This, together with a relatively workable soil (cone resistance = 529 ± 26 N cm?2 at the end of June, with 10% soil humidity), indicates moderate ecological conditions, which disagrees with the aridity food-distribution hypothesis (AFDH) considering small body size and sociality in bathyergids adaptations to harsh environments.  相似文献   

9.
PurposeThis study evaluated whether RapidPlan based plans (RP plans) created by a single optimization, are usable in volumetric modulated arc therapy (VMAT) for patients with prostate cancer.MethodsWe used 51 previously administered VMAT plans to train a RP model. Thirty RP plans were created by a single optimization without planner intervention during optimization. Differences between RP plans and clinical manual optimization (CMO) plans created by an experienced planner for the same patients were analyzed (Wilcoxon tests) in terms of homogeneity index (HI), conformation number (CN), D95%, and D2% to planning target volume (PTV), mean dose, V50Gy, V70Gy, V75Gy, and V78Gy to rectum and bladder, monitor unit (MU), and multi-leaf collimator (MLC) sequence complexity.ResultsRP and CMO values for PTV D95%, PTV D2%, HI, and CN were significantly similar (p < 0.05 for all). RP mean dose, V50Gy, and V70Gy to rectum were superior or comparable to CMO values; RP V75Gy and V78Gy were higher than in CMO plans (p < 0.05). RP bladder dose-volume parameter values (except V78Gy) were lower than in CMO plans (p < 0.05). MU values were RP: 730 ± 55 MU and CMO: 580 ± 37 MU (p < 0.05); and MLC sequence complexity scores were RP: 0.25 ± 0.02 and CMO: 0.35 ± 0.03 (p < 0.05).ConclusionsRP plans created by a single optimization were clinically acceptable in VMAT for patient with prostate cancer. Our simple model could reduce optimization time, independently of planner’s skill and knowledge.  相似文献   

10.
Hypoxia is an important environmental stressor to marine species, especially in benthic coastal waters. Increasing anthropogenic emissions of nutrients and organic matter contribute to the depletion of dissolved oxygen (DO). Biotic sensitivity to low levels of DO is determined by the organisms’ ability to use DO as a respiratory gas, a process depending on oxygen partial pressure. A method is proposed to estimate an indicator of the intensity of the effects caused by hypoxia on exposed marine species. Sensitivity thresholds to hypoxia of an exposed ecological community, modelled as lowest-observed-effect-concentrations (LOEC), were compiled from literature for 91 benthic, demersal and benthopelagic species of fish, crustaceans, molluscs, echinoderms, annelids, and cnidarians, and converted to temperature-specific benthic (100 m depth) LOEC values. Species distribution and LOEC values were combined using a species sensitivity distribution (SSD) methodology to estimate the DO concentration at which the potentially affected fraction (PAF) of the community's species having their LOEC exceeded is 50% (HC50LOEC). For the purpose of effect modelling in Life Cycle Impact Assessment (LCIA), Effect Factors (EF [(PAF) m3 kgO2−1]) were derived for five climate zones (CZ) to represent the change in effect due to a variation of the stressor intensity, or EF = ΔPAF/ΔDO = 0.5/HC50LOEC. Results range from 218 (PAF) m3 kgO2−1 (polar CZ) to 306 (PAF) m3 kgO2−1 (tropical CZ). Variation between CZs was modest so a site-generic global EF of 264 (PAF) m3 kgO2−1 was also estimated and may be used to represent the average impact on a global ecological community of marine species exposed to hypoxia. The EF indicator is not significantly affected by the major sources of uncertainty in the underlying data suggesting valid applicability in characterisation modelling of marine eutrophication in LCIA.  相似文献   

11.
A new phytoplankton-based index was designed to respond to the Water Framework Directive (WFD) requirements concerning the assessment of lake ecological status. The “Indice Phytoplancton Lacustre” (IPLAC) is a multimetric index, taking into account biomass, abundance and species composition of communities. The first metric is based on the total phytoplankton biomass (MBA), the second on the abundance and taxonomic composition (MCS) of 165 indicator taxa. The IPLAC was developed on 2 independent databases, one for the calibration and the second for the validation of the metrics. The calibration dataset was composed of 255 “lake-years” from 214 distinct lakes sampled between 2005 and 2012. The validation dataset included 173 lake-years in order to confirm the response of the index to the trophic gradient and anthropogenic pressure.The results show that the IPLAC correctly highlights chemical pressure (eutrophication). Especially high Pearson correlations are shown with total phosphorus (r = −0.71, p-value <0.001), chlorophyll-a (r = −0.83, p-value <0.001) and water transparency (r = 0.73, p-value <0.001) which are the main proxies for the trophic level. Corine land cover was used as an indication of the anthropogenic pressure and good correlations are also found with the watershed land use, negatively correlated with agricultural area (r = −0.60, p-value <0.001), population density (r = −0.36, p-value <0.001) and positively with forest area (r = 0.57, p-value <0.001).The index is WFD-compliant and is dedicated to natural lakes and artificial water bodies in metropolitan France, and will be routinely used by the French Ministry of the Environment to assess lake ecological status through the phytoplankton community. However, the results must be carefully interpreted in two cases: reservoirs with large water level fluctuations, and samples that include less than 5 indicator species.  相似文献   

12.
Duckweeds, as a group, are important early warning indicators for the assessment of contaminated ecosystems due to their propensity to accumulate pollutants. In the present study, we investigated the potential use of Lemna gibba L. (Lemnaceae) as an ecological indicator for boron (B) mine effluent containing B concentration above 10 mg l−1. For this purpose, L. gibba fronds were grown for 7 days in simulated water contaminated with B mine effluent. The important note is that this study was carried out in Kırka (Eskişehir, Turkey) B reserve area, which is the largest borax reserve in all over the world, under natural climatic conditions in the field. The results demonstrated that accumulations of B by L. gibba gradually increased based on the initial B concentrations (10, 25, 50, 100, and 150 mg l−1) of the mine effluent. B concentration in the dry weight of the plant reached 639 mg kg−1 when the minimum initial dosage (10 mg l−1) was applied and 2711 mg kg−1 when the maximum initial dosage (150 mg l−1) was applied during the study. However, significant reductions in their relative growth rates occurred in 50, 100 and 150 mg l−1 initial B concentrations. Results suggest that 25 mg l−1 B concentration in water seemed to be a sensitive endpoint for L. gibba that could be used as a critical bioindicator level of B contaminated water. Following our data, we also constructed a simple growth model under the climatic conditions in this region of Turkey, but in instructive as a worldwide model. L. gibba is, therefore, suggested to be able to use as both an indicator and a phytoremediation tool because of its high accumulation capacity for B contaminated water.  相似文献   

13.
To eliminate the diastereomer interference on Telcagepant (MK-0974) determination during clinical study support, on-line high turbulent-flow liquid chromatography (HTLC) methods, HTLC-A and HTLC-B that covered dynamic range of 0.5–500 nM and 5–5000 nM, respectively, were developed. To meet the requirement of rapid assay transfer among multiple laboratories and analysts, a solid-phase extraction (SPE) assay was derived from the existing HTLC-B assay under the same dynamic range. The on-line HTLC assays were achieved through direct injection of plasma samples, extraction of analyte with a Cohesive C18 column (50 mm × 0.5 mm, 50 μm), followed by HPLC separation on a FluoPhase RP column (100 mm × 2.1 mm, 5 μm) and MS/MS detection. The off-line SPE assay used Waters Oasis®HLB μElution plate to extract the analytes from plasma matrix before injecting on a FluoPhase RP column (150 mm × 2.1 mm, 5 μm) for LC–MS/MS analysis. Under both on-line and off-line assay conditions, the diastereomer 1c was chromatographically separated from MK-0974. Cross-validation with the pooled samples demonstrated that both on-line and off-line assays provided comparable data with a difference of <2.6%. The assays were proved to be specific, accurate and reliable, and have been used to support multiple clinical studies. The pros and cons of on-line and off-line assays with regard to man power involved in sample preparation, total analysis time, carryover, cost efficiency, and the requirement for assay transfer are discussed.  相似文献   

14.
Effects of daily protein intake levels on oral stereotypic behaviours (OSB) in energy restricted lambs were investigated. Thirty-eight male lambs were randomly allotted to three treatments. Lambs in the first group (AL) received their ration (12.1 MJ ME/kg DM; 148.6 g CP/kg DM) at ad libitum level, whereas the second group (RP1) (12.1 MJ ME/kg DM; 177.4 g CP/kg DM) and the third group (RP2) (12.1 MJ ME/kg DM; 214.9 g CP/kg DM) received their rations at restricted levels. Recording of behaviours was carried out once a week using time sampling technique during a 7-week experimental period. OSB were significantly (P<0.001) affected by the treatments. RP2 group showed higher oral stereotypies than the others. It was concluded that increasing the daily protein intake under energy restricted conditions may have additive effects on the development of stereotypic oral behaviours.  相似文献   

15.
Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50 = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC50 = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC50 = 1129.32 ± 88.79 μM) and α-tocopherol (EC50 = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC50 = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC50 = 157.54 ± 21.30 μM; synthetic (R,R)-SDG-2: EC50 = 123.63 ± 8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use.  相似文献   

16.
《Mycological Research》2006,110(8):985-993
Mycelial development of Phanerochaete velutina extending from wood inocula in 57 × 57 cm trays of non-sterile soil was characterized after adding: (1) collembola; (2) new wood resources; (3) both new wood resources and collembola; and (4) no new resources and no collembola. After 99 d, all systems had produced distinct mycelial cords, much of the diffuse mycelium and thinner cords that were produced early on having regressed. Systems to which new resources (but no collembola) had been added developed thick cords interconnecting inocula with new resources, and much of the non-connected mycelium regressed. Nonetheless, these systems had significantly greater hyphal coverage and mass fractal dimension than the other treatments, resulting from outgrowth from the new resources. Unexpectedly, morphology of grazed systems with no added resources was very similar to that of ungrazed systems with no added resources, apparently because the collembola grazed on senescing hyphae that would ultimately have regressed. Where new resources and collembola were added, there was proliferation of fine mycelium along connective cords and elsewhere, but this was not as extensive as in the new resource/no collembola systems, the fine mycelium apparently being grazed in patches. Fungus gnat (family Sciaridae) larvae contaminated eight (out of 14) trays with no added collembola, but none of the systems to which collembola had been added. They burrowed around the wood and caused cords to be severed.  相似文献   

17.
The bumblebee, Bombus ardens, is a valuable natural resource, and is most notably utilized for greenhouse pollination. In order to gain a greater understanding of the population genetic structure and the genetic diversity of this species, we sequenced a portion of the mitochondrial COI gene corresponding to the “DNA Barcode” region (658 bp) from 160 individuals collected over 15 Korean localities. Uncorrected pairwise distances among the eight haplotypes suggested low intraspecific genetic diversity, with a maximum sequence divergence of 0.3%. Such a low level of intraspecific genetic diversity was further reflected in local populations, particularly to islet populations, such as those of Youngheungdo, Jakyakdo, and Ulleugdo, which had zero genetic diversity. Geographically, one haplotype (BARBA01) was widespread and dominant, with a frequency of 90.6% (145 among 160 individuals). Other haplotypes were restricted to one to three localities and had low frequency. Overall, a very high rate of per generation female migration ratio (Nm = 4.6 to infinite) and a very low level of genetic fixation (FST = 0 to 0.099) were detected between pairs of localities, suggesting that the B. ardens populations on the Korean peninsula are panmictic, which is consistent with our understanding of their dispersal capability.  相似文献   

18.
The life-cycle greenhouse gaseous emissions and primary exergy resources consumption associated with a horizontal subsurface flow constructed wetland (HSSF) were investigated. The subject of study was a wetland for municipal wastewater treatment with a 700-person-equivalent capacity. The effects of two types of emergent aquatic macrophytes (Phragmites australis and Schoenoplectus californicus) and seasonality on greenhouse gas (GHG) gas emissions, the environmental remediation cost (ERC) and the specific environmental remediation cost (SERC) were assessed. The results indicate that GHG emissions per capita (12–22 kgCO2eq/p.e/yr) and primary exergy resources consumed (24–27 MJ/m3) for the HSSF are lower than those of a conventional wastewater treatment plant (67.9 kgCO2eq/p.e/yr and 96 MJ/m3). The SERC varied between 176 and 216 MJ/kg biological oxygen demand (BOD5) removal, which should be further reduced by 20% for an improved BOD5 removal efficiency above 90%. The low organic matter removal efficiency is associated with a high organic load and low bacterial development. Seasonality has a marked effect on the organic removal efficiency and the SERC, but the macrophyte species does not.  相似文献   

19.
Chromium trispicolinate (CrPic) is a popular dietary supplement that is not regulated by the Food and Drug Administration. We are using this compound as a bio-available model to explore the role of Cr(III) in Cr(VI)-induced cancers. The ability of CrPic to cause mutations at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) locus of CHO AA8 cells has been measured after a 48 h exposure. The highest dose tested was 80 μg/cm2 CrPic, which, if fully soluble, would be equivalent to 1 mM or 0.44 mg/ml CrPic, and would correspond to 1 mM Cr(III) or 52 μg/ml Cr(III). This exposure resulted in 68±16% cell survival based on 48 h cell counts, and 24±11% survival by 7-day colony formation. Exposure of CHO cells to CrPic produced a statistically significant increase in 6-thioguanine (6-TG)-resistant cells over the dose range tested. The 80 μg/cm2 CrPic exposure resulted in an average induced mutation frequency (MF) of 58 per 106 surviving cells, or an average 40-fold increase in hprt mutants relative to untreated cells. An equivalent dose of 3 mM Pic was highly cytotoxic and did not yield hprt mutants. The dose range of 0.375–1.5 mM Pic produced a slight increase in hprt mutants, but the increase was not statistically significant. An equivalent dose of 1 mM chromic chloride yielded an induced MF of 9 per 106 surviving cells, or a 10-fold increase in mutants with cell survivals of >100%. The coordination of Cr(III) with picolinic acid may make the metal more genotoxic than other forms of Cr(III). In light of the current results and the known ability of Cr(III) and CrPic to accumulate in tissues, as well as the growing evidence of Cr(III) involvement in Cr(VI)-induced cancers, we caution against ingestion of large doses of CrPic for extended periods.  相似文献   

20.
The present work evaluated the synergistic effects of soil fertilization with rock P and K materials and co-inoculation with P and K-dissolving bacteria [PDB (Bacillus megaterium var. phosphaticum) and KDB (Bacillus mucilaginosus and B. subtilis)] on the improvement of P and K uptake, P and K availability and growth of maize plant grown under limited P and K soil conditions (calcareous soil). The experiment was establishment with eight treatments: without rock P and K materials or bacteria inoculation (control), rock P (RP), rock K (RK), RP + PDB, RK + KDB and R(P + K)+(P + K)DB. Under the same conditions of this study, co-inoculation of PDB and KDB in conjunction with direct application of rock P and K materials (R(P + K)) into the soil increased P and K availability and uptake, and the plant growth (shoot and root growth) of maize plants grown on P and K limited soils.  相似文献   

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