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Nat Commun ; 10(1): 5230, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31745089


The Hengduan Mountains (HDM) biodiversity hotspot exhibits exceptional alpine plant diversity. Here, we investigate factors driving intraspecific divergence within a HDM alpine species Salix brachista (Cushion willow), a common component of subnival assemblages. We produce a high-quality genome assembly for this species and characterize its genetic diversity, population structure and pattern of evolution by resequencing individuals collected across its distribution. We detect population divergence that has been shaped by a landscape of isolated sky island-like habitats displaying strong environmental heterogeneity across elevational gradients, combined with population size fluctuations that have occurred since approximately the late Miocene. These factors are likely important drivers of intraspecific divergence within Cushion willow and possibly other alpine plants with a similar distribution. Since intraspecific divergence is often the first step toward speciation, the same factors can be important contributors to the high alpine species diversity in the HDM.

Huan Jing Ke Xue ; 39(6): 2936-2943, 2018 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965653


Based on the typical greenhouse vegetable production system in Siping City, Jilin Province, 124 soil samples were collected from greenhouse soils growing vegetables (GSGV), fields growing maize (FGM), and forest soil (FS) under different land utilization patterns. In addition, other samples including greenhouse vegetables (81), fertilizers (50), and irrigation water (10) were also collected in the studied region. To illustrate the accumulation characteristics of heavy metals in GSGV and greenhouse vegetables, the heavy metal content of different samples was measured using inductively coupled plasma mass spectrometry (ICP-MS) technology. The results indicated that the heavy metal content in GSGV was much higher than that in FGM and FS except for lead (Pb). Heavy metals including cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) in GSGV presented with various degrees of accumulation. The mean value of Cd content in the soils in the investigation region was 0.45 mg·kg-1, with about 42.8% of all the soil samples exceeding the Cd content criterion of the Environmental Quality Evaluation Standard for Farmland in Greenhouse Vegetable Production (HJ 333-2006). The content of the other heavy metals was in the normal range, and all met the regulations of the standard. In comparison with different vegetable categories, leafy vegetables showed much higher heavy metal concentrations (Cd 0.033 mg·kg-1 fresh weight) than did fruity ones. In total, about 2.5% and 1.2% of vegetable samples exceeded the regulated values of Cd and Pb recommended by the Standard of Food limits, respectively. With the cultivation time prolonged, heavy metal concentration in soils and vegetables all increased synchronously as the pH value decreased. The content of heavy metals in greenhouse vegetables was significantly influenced by soil pH and organic matter. It can be concluded that the health risk of greenhouse vegetables increased with GSGV accumulating more heavy metals due to the substantial application of chemical fertilizer and manure containing high level of heavy metals.

Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Verduras/química , Agricultura , China , Cidades
Environ Sci Pollut Res Int ; 24(23): 19375-19385, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28674954


Staphylococcal enterotoxin A (SEA) was the major virulence factor of Staphylococcus aureus and a biomarker of S. aureus. To establish a fast, low cost, high accuracy, reliable, and simple method for detecting S. aureus, SEA was analyzed by HPLC-ESI-TOF. SEA was not yet commercially available in universal, so SEA was prepared before it was analyzed by HPLC-ESI-TOF. The result showed that high purified SEA was successfully prepared and SEA has normal distribution in mass spectra. A large amount of recombinant SEA (rSEA) was obtained by engineering technology and was purified by Ni affinity chromatography column, and the expression and purity of rSEA and SEA were analyzed by SDS-PAGE. The factors effected on ionization of SEA were studied, and the qualitative analysis of SEA by HPLC-ESI-TOF. The result showed that large amount of SEs expressed within a short time at 28 °C or thereabouts, and there was no impurity bands in electrophorogram after rSEA was purified by Ni affinity chromatography column. In addition, the SEA which had homologous AA sequence with wild SEA was made by rSEA. The retention of SEA in column and ionization of SEA in ESI-TOF were studied for qualitative analysis of S. aureus. The result showed that the content of formic acid in mobile phase was an important factor for ionization of SEs in ESI-TOF. And the result provided theoretical foundation for qualitative detection of S. aureus. [SEs + nH+ + mNH4+] n+m+ was shown on ESI-TOF spectra when SEA was detected by ESI-TOF in positive ion mode, and the numerical value of n+m was less than or equal to the number of basic amino acids in SEs. This method was applied to determine SEA in water samples preliminarily, and the detection limit of SEA in spiked water sample was 3 mg/kg. The limit of detection of 3 mg/kg was low sensitivity for low molecular weight matters, but it was high sensitivity for SEA which had a high molecular weight of 27 kDa. Of SEA, 3 mg/kg was equivalent to 10-4 mmol/kg of SEA. This study can provide evidence for establishing method to determine SEA in real samples.

Técnicas de Química Analítica/métodos , Enterotoxinas/análise , Enterotoxinas/biossíntese , Staphylococcus aureus/química , Água/química , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Enterotoxinas/isolamento & purificação , Engenharia Genética , Espectrometria de Massas , Proteínas Recombinantes/análise , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Staphylococcus aureus/genética
J Chromatogr A ; 1446: 59-69, 2016 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-27086566


A novel, rapid and simple analytical method was developed for the quantitative determination of crocin, crocetin and geniposide in soft drink, pastry and instant noodles. The solid samples were relatively homogenized into powders and fragments. The gardenia yellow colorants were successively extracted with methanol using ultrasound-assisted extraction. The analytes were quantitatively measured in the extracts by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. High correlation coefficients (r(2)>0.995) of crocin, crocetin and geniposide were obtained within their linear ranges respectively (50-1000ng/mL, 50-1000ng/mL, 15-240ng/mL) by external standard method. The limits of detection (LODs) were 0.02µg/g for crocin, 0.01µg/g for crocetin and 0.002µg/g for geniposide. And the limits of quantitation (LOQs) were in the ranges of 0.05-0.45µg/g for crocin, and in the ranges of 0.042-0.32µg/g for crocetin, and in the ranges of 0.02-0.15µg/g for geniposide in soft drink, pastry and instant noodles samples. The average recoveries of crocin, crocetin and geniposide ranged from 81.3% to 117.6% in soft drink, pastry and instant noodles. The intra- and inter-day precisions were respectively in the range of 1.3-4.8% and 1.7-11.8% in soft drink, pastry and instant noodle. The developed methods were successfully validated and applied to the soft drink, pastry, and instant noodles collected from the located market in Beijing from China. Crocin, crocetin and geniposide were detected in the collected samples. The average concentrations ranged from 0.84 to 4.20mg/g for crocin, and from 0.62 to 3.11mg/g for crocetin, and from 0.18 to 0.79mg/g for gardenia in various food samples. The method can provide evidences for government to determine gardenia yellow pigments and geniposide in food.

Carotenoides/análise , Corantes/análise , Análise de Alimentos , Gardenia/química , Iridoides/análise , Extratos Vegetais/química , Pequim , Bebidas Gaseificadas/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
Anal Chem ; 85(1): 273-7, 2013 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-23215038


A bovine serum albumin (BSA)-monolayer-based probe carrier platform is shown to improve the performance of a conventional thiolated single-stranded DNA probe self-assembled-monolayer-based electrochemical DNA hybridization biosensor. A detection limit of 0.5 fM can be obtained in a very reproducible manner (relative standard deviation <5%), along with high specificity. The performance of the biosensor can be attributed primarily to the enhanced spatial positioning range and accessibility of the probes on the BSA-based platform. Furthermore, the novel biosensor shows high resistance to nonspecific adsorption of nucleic acid and protein and can be directly employed in detection in biological fluids. These advantages give this simple developed methodology great promise for a wide range of nucleic acid testing.

Técnicas Biossensoriais , Sondas de DNA/química , DNA/análise , Técnicas Eletroquímicas , Soroalbumina Bovina/química , Animais , Bovinos , DNA de Cadeia Simples/química , Eletrodos , Ouro/química , Hibridização de Ácido Nucleico
Anal Chim Acta ; 748: 89-94, 2012 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-23021812


An ultrasensitive electrochemical impedance spectroscopic deoxyribonucleic acid biosensor has been developed based on the conformational change of the deoxyribonucleic acid recognition interface with lodging probes. Pairing process leads to desorption of deoxyribonucleic acid bases from the gold surface, leading to a significant change of the interfacial conformation and the charge transfer resistance. Remarkably low detection limits down to 40 fM are thus obtained without any additional amplification step.

Técnicas Biossensoriais , DNA/química , Técnicas Eletroquímicas , Espectroscopia Dielétrica , Limite de Detecção , Modelos Moleculares , Conformação Molecular