Objective: Quantitation of urinary metabolites of four PAHs, selected on the basis of their significance, with reduced costs and high sensitivity.
Materials and methods: HPLC-MS/MS was used and pure standards and isotope-labeled internal analogs of the analytes. Two hundred samples were tested after enzymatic hydrolysis.
Results: Accuracy was higher than 90% and variability lower than 19%; LODs permit to measure 1-hydroxypyrene, 1 and 2-hydroxynaphthalene in all subjects, 6-hydroxynitropyrene in the 65% and 3-hydroxybenzo[a]pyrene in the 70%.
Discussion and conclusion: The method is suitable both for occupational and for environmental studies. This is the first paper reporting urinary levels of 6-hydroxynitropyrene in European subjects, nonoccupationally exposed to nitro-PAHs. 相似文献
Aims: We address three hypotheses: H1, diversity of mycorrhizal fungi in serpentine soils mirrors above-ground plant diversity; H2, the morphology of mycorrhizas and fungi on serpentine soils differs from that on non-serpentine; and H3, mycorrhizal fungal communities of the same or closely related hosts differ between serpentine and non-serpentine soils.
Methods: This review focuses on whether plant diversity on serpentine soils correlates with the below ground diversity of mycorrhizal fungi.
Results: Studies show that plants and fungi formed abundant ectomycorrhizal and arbuscular mycorrhizal symbioses on and off serpentine soils. No serpentine-endemic fungi were identified. Molecular analyses indicate distinct serpentine isolates for Cenococcum geophilum and for Acaulospora, suggesting adaptation to serpentine soils. While fungal sporocarp assemblages on serpentine sites resembled those off serpentine, fruiting of hypogeous fungi was greatly reduced.
Conclusions: Ectomycorrhizal fungal communities did not differ between soil types; however, arbuscular mycorrhizal communities differed in some cases but not others. The additive response to multiple factors, described as the serpentine syndrome, may explain part of the response by fungi. 相似文献
Aims: We investigated the effect of plant sex on rhizosphere nematode communities associated with Corema album, a dioecious shrub occurring in coastal habitats.
Methods: Rhizosphere samples were collected from males and females in three populations (150 plants), during fruiting and flowering. Nematode communities were characterised and compared between plant sexes through statistical analyses of the abundance of trophic groups, plant parasitic nematode (PPN) genera and ecological indices.
Results: Free-living nematodes showed no statistically significant differences owing to plant sex. Conversely, PPN community composition was significantly different between plant sexes during fruiting but not flowering, suggesting that physiological requirements over the annual phenological cycle of the plant influence ecological interactions with the rhizosphere.
Of the 13 PPN genera identified, the ectoparasitic Criconema and Hemicriconemellawere more abundant in the rhizosphere of males during fruiting, whereas the endoparasitic Meloidogyne associated more frequently with females, suggesting that plant host suitability is related to PPN feeding strategy.
Conclusions: It appears that interactions of individuals of different sexes of C. album with the rhizosphere nematode community vary with phenological stage, especially for PPN. 相似文献
Methods. A voucher of the Chinese specimen is deposited in IFP herbarium. This specimen was studied with the typical anatomical and morphological methods applied within Grimmia (Maier, 2010).
Key Results. The Chinese species represents G. exquisita. After examining the type specimens of G. exquisita, we confirmed that it should be recognised as a distinct species.
Conclusions. This study expands the distribution area of G. exquisita to East Asia. The Chinese specimen was discovered in a rather different habitat to its types and consequently, G. exquisita may be a more widely distributed species. Evaluation of the Grimmia specimens in many different herbaria is needed. 相似文献
The annual removal of the soil activity with the biomass was less than 0.1%. The addition of citric acid (25 mmol kg-1) 1 week before the harvest increased U uptake up to 500-fold. With a ryegrass and mustard yield of 15000 kg ha-1 and 10000 kg ha-1, respectively, up to 3.5% and 4.6% of the soil activity could annually be removed with the biomass.
With a desired activity reduction level of 1.5 and 5 for the bicarbonate washed and control soil, respectively, it would take 10 to 50 years to attain the release limit.
A linear relationship between the plant 238U concentration and the 238U concentration in the soil solution of the control, bicarbonate-washed, or citric acid-treated soil points to the importance of the soil solution activity concentration in determining U uptake and hence to the importance of solubilising agents to increase plant uptake.
However, citric acid addition resulted in a decreased dry weight production (all plants tested) and crop regrowth (in case of ryegrass). 相似文献
Aims: We investigated the geographical variation of flower colour (and correlated traits) in Gentiana lutea and the relationship with the variation in abiotic factors.
Methods: Phenotypic variation (flower colour, petal length, petal width, stalk length, leaf length, flower number, petal number and number of basal leaves) was assessed in 429 plants of 12 populations located at north-west Iberia. Additionally, we obtained data on the geographical coordinates, elevation, temperature, rainfall and radiation for each population.
Results: Populations mostly differed in flower colour, from orange to yellow from west to the east. Abiotic factors were unrelated to variation in either floral or vegetative traits.
Conclusions: Phenotypic variation among G. lutea populations does not result from adaptation to environmental factors. Other factors, such as historical events or selective pressure exerted by biotic interactions, might explain the flower colour variation in G. lutea along the Cantabrian Range. 相似文献
Aims: We used greenhouse experiments to test whether Tragopogon dubius, a species that has recently expanded its range northward and colonised the Netherlands, is able to associate with the same AMF as the native congener T. pratensis.
Methods: In soils collected from four locations in the new range of T. dubius we compared the density of infective AMF propagules associating with both plant species, as well as AMF colonisation of the roots. The AMF community structure in the roots of these species was also analysed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE).
Results: Tragopogon dubius and T. pratensis did not differ in any of these characteristics.
Conclusions: We therefore conclude that the range-shifting T. dubius is as effective in the formation of mycorrhiza as the native congener. 相似文献
Methods. After critical investigation, they have been described as new to science and both species, C. ghatensis G.Asthana & A.Srivastava sp. nov. and C. mehrana G.Asthana & A.Srivastava sp. nov. are illustrated and described here.
Key results. Cololejeunea ghatensis is an epiphyllous species growing on angiosperm leaves and has been collected near Chinaman Waterfall, Robbers Cave, Connaught Peak and Polo Ground area. Cololejeunea mehrana has been collected near Monkey point and the latter has an interesting habitat as it was found growing on moss leaves. Cololejeunea ghatensis is monoicous and C. mehrana is dioicous. 相似文献
Methods: The efficacy of C-PC was evaluated against the proliferation of ESCC cell lines EC9706 and EC1 by CCK-8 kit and in a mice model of ESCC EC9706. Cell cycle and apoptosis were investigated by flow cytometry, and cell invasion was determined via transwell chamber. Protein expression was examined by Western blots.
Results: We found that C-PC exhibited anti-proliferation ability in a time-dependent manner and a dose-dependent manner in ESCC EC9706 and EC1 cells. Besides, C-PC markedly arrested cell cycle in the G0/G1 phase, induced cell apoptosis and suppressed cell invasion ability in both EC9706 and EC1 cells (p?<?.01). Notably, C-PC evoked the elevations of Bax, PARP, and cleaved-caspase-3 protein, but reduced cyclin D1, CDK4, Bcl-2, MMP-2, and MMP-9 expression levels. Further investigation from in vivo experiment revealed that C-PC displayed significant antitumor efficacy in the xenografted EC9706 model.
Conclusions: Our data presented herein suggest C-PC exerts antitumor efficacy in ESCC. 相似文献
Methods: Wistar rats underwent running training for 6 weeks. In vitro measurements of hydroxyl radical production, oxygen consumption (under basal and maximal respiration conditions) and ATP production were made on permeabilized fibers. Mitochondrial function was examined after exposure and non-exposure to an in vitro generator system of reactive oxygen species (ROS). Antioxidant enzyme activities and malondialdehyde (MDA) content were also determined.
Results: Compared with sedentary males, females showed a greater resistance of mitochondrial function (oxygen consumption and ATP production) to ROS exposure, and lower MDA content and antioxidant enzyme activities. The training protocol had more beneficial effects in males than females with regard to ROS production and oxidative stress. In contrast to male rats, the susceptibility of mitochondrial function to ROS exposure in trained females was unchanged.
Discussion: Exercise training improves mitochondrial function oxidative capacities in both male and female rats, but is more pronounced in males as a result of different mechanisms. The resistance of mitochondrial function to in vitro oxidative stress exposure and the antioxidant responses are gender- and training-dependent, and may be related to the protective effects of estrogen. 相似文献
Methods: Two polymorphisms of TGF-β2 gene were genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) from 259 CTDs patients and 310 control subjects.
Results: The association between SNP rs6658835 in TGF-β2 and CTDs has been found. The frequency of G allele in CTDs patients was significantly higher than that in control subjects (52.7% versus 40.3%, p?<?0.001, OR =1.649).
Conclusion: TGF-β2 gene polymorphisms may serve as a novel genetic marker for the risk of CTDs. 相似文献
Aims: This study had the aim of determining variation in liana diversity, structure and habitat associations across different topographic habitats, and the environmental factors influencing them, in the Penang Hill Forest Reserve, Malaysia.
Methods: Liana diversity, structure and habitat associations were examined in 30 plots, 40 m × 40 m, randomly demarcated within three topographic habitats (flatland, slope and valley). The physico-chemical properties of the soils in the plots were determined and the altitude and slope of the plots recorded.
Results: Liana species richness, diversity and structure varied significantly among the topographic habitats. Liana species richness, diversity and abundance variations were related to soil moisture, phosphorus content, pH and altitude, whereas liana diameter and basal area were associated with soil magnesium and slope. A total of eight species had a positive association with the habitat and a further six showed a negative association. Four species had a positive association with the flatland habitat, but only three and two species, respectively, with slope and valley habitats. The slope habitat gave the highest number of species that showed a negative association.
Conclusions: Liana diversity and structure varied between habitats. Some liana species showed different associations with specific habitats. Environmental variables were identified that influence liana diversity, structure and habitat associations. The study provides important information about the factors influencing liana success, and these will be of value in liana conservation and management in tropical forests. 相似文献
Objective: The study examined the early release kinetics of TnTuORF.
Materials and methods: We analyzed the time course of the release of cardiac troponins I and T and TnTuORF in patients (n?=?31) with hypertrophic obstructive cardiomyopathy undergoing transcoronary ablation of septal hypertrophy (TASH).
Results: Fifteen minutes after TASH, the levels of both troponins increased significantly (cTnT median: 18?ng/L versus 27?ng/L; cTnI median: 15?ng/L versus 25?ng/L). TnTuORF showed no variation.
Discussion: We observed a significantly greater increase in cTnI compared with cTnT.
Conclusion: Our results demonstrate that troponin assays allow early detection of myocardial injury, whereas TnTuORF levels remain unchanged in this setting. 相似文献
Objective/Aim: In this work, we investigated the possible effect of lipid composition on the incorporation of trastuzumab-PEG-PE micelles into nanoliposomes and on their subsequent specific cellular targeting.
Materials and methods: Trastuzumab (anti-HER2 monoclonal antibody) was monothiolated and conjugated to maleimide-PEG-PE micelles. Liposomes of different lipid compositions were prepared by the thin layer hydration. Trastuzumab-PEG-PE micelles were incorporated into the liposomes by the post-insertion method. The percentage of lipid mixing was determined based on fluorescence resonance energy transfer. Cellular binding and uptake of rhodamine-labeled immunoliposomes were studied in SKBR-3 (HER2+++) and MCF-7 (HER2+) cells. Also, antitumor cell activity of the immunoliposomes was compared to free trastuzumab and the liposomes.
Results: The lipid mixing of trastuzumab-PEG-PE micelles depended on the liposome composition. The immunoliposomes containing DPPC, cholesterol and PEG-PE showed prominent lipid mixing. The lipid mixing was consistent with the cell binding results which showed an efficient and specific binding of the immunoliposomes to SKBR-3 cells. Antitumor cell activity of the immunoliposomes in SKBR-3, unlike MCF-7 cells, depended on the content of trastuzumab.
Discussion: Cholesterol and PEG-PE in the liposome composition are prerequisites for a successful lipid mixing due to their ability to facilitate fusion. The higher lipid mixing results in higher antibody incorporation and consequently higher targeted cell binding.
Conclusions: The lipid mixing depends on the liposome composition, which reflects targeted cell binding of the immunoliposomes. 相似文献
Objective: To investigate whether polymorphisms in IL21 gene contribute to sepsis susceptibility.
Materials and methods: Three single-nucleotide polymorphisms of IL21 (rs907715, rs2055979, rs12508721) were genotyped by TaqMan assay in patients with sepsis and control subjects.
Results: Polymorphisms rs2055979 and rs12508721 in IL21 were more frequent in sepsis patients compared to general population. But allele frequency of rs907715 was not significantly different between sepsis patients and control subjects.
Conclusion: Polymorphisms in IL21 may be associated with sepsis risk. 相似文献
Aims: To test whether the interactions between these two species are related to competition or facilitation, which would change the perspective for their management in mountain heathlands.
Methods: A total of 40 experimental plots located in a montane heathland (northern Spain) were selected. Calluna or Vaccinium plants were either cut at ground level or not cut, and plots were fertilized with nitrogen or not in a three-factorial design. Vegetative and reproductive shoot mass and length of the current year’s shoots were estimated in two consecutive years for both species. Herbivory on Vaccinium by browsing ungulates was compared in control plots and plots where Calluna had been cut 2 yrs ago.
Results: The two study species co-occurred in 72.4% of the sampled plots, although Calluna was more abundant. Vaccinium growth was greater in plots with Calluna than in plots where Calluna had been cut. Browsing on Vaccinium was also higher in plots were Calluna had been cut, and the effect of fertilization was only significant on the reproductive biomass of Calluna.
Conclusions: Contrary to initial proposals, our results suggest that Vaccinium does not always benefit from the cutting of Calluna in heathlands. Thus, the management of Cantabrian mountain heathlands should consider maintaining Calluna in order to facilitate the growth of Vaccinium. 相似文献