Institutional Repository of Chengdu Institute of Biology, CAS
Not a member yet
6513 research outputs found
Sort by
Simultaneous determination of trace Aflatoxin B-1 and Ochratoxin A by aptamer-based microchip capillary electrophoresis in food samples
No full textAn aptamer-based microchip capillary electrophoresis coupled with laser induced fluorescence (MCE-LIF) detection method for fast determination of Aflatoxin B-1 (AFB(1)) and Ochratoxin A (OTA) was developed. Aptamers that are specific to these two mycotoxins were first hybridized with their aptamer complementary oligonucleotides. The double strand DNA that comes in contact with mycotoxin-containing environment would be unwound into separate aptamer-mycotoxin complex and aptamer complementary single strand. Different types of oligonucleotides can be separated in MCE and detected under the aid of fluorescent dye SYBR gold in LIF detection unit. Under the optimal conditions, on-chip aptamer-mycotoxin conjugates analysis was achieved within 3 min with extremely low LODs (0.026 ng/mL for AFB(1) and 0.021 ng/mL for OTA). Specificity study indicated that other major mycotoxins would not cross-react with these two aptamers, demonstrating the good selectivity of the proposed method. Quantification of trace AFB(1) and OTA in real food samples was carried out and satisfactory recoveries were obtained. It is demonstrated that this method is fast, facile and specific for Simultaneous determination of trace AFB(1) and OTA from foodstuffs. (C) 2018 Elsevier B.V. All rights reserved
New combinations in the fern genus Leptochilus (Polypodiaceae)
No full textFollowing the results of a molecular phylogeny we made nine new combinations in Leptochilus based on morphological, ecological, and distributional evidence. The new combinations include: Leptochilus chilangensis, L. chingii, L. dissimilialatus, L. evrardii, L. flexilobus, L. fluviatilis, L. pentaphyllus, L. poilanei, and L. saxicola
Assessing changes in the value of ecosystem services in response to land-use/land-cover dynamics in Nigeria
No full textIncreasing human activities worldwide have significantly altered the natural ecosystems and consequently, the services they provide. This is no exception in Nigeria, where land-use/land-cover has undergone a series of dramatic changes over the years mainly due to the ever-growing large population. However, estimating the impact of such changes on a wide range of ecosystem services is seldom attempted. Thus, on the basis of GlobeLancd30 land-cover maps for 2000 and 2010 and using the value transfer methodology, we evaluated changes in the value of ecosystem services in response to land-use/land-cover dynamics in Nigeria. The results showed that over the 10-year period, cultivated land sprawl over the forests and savannahs was predominant, and occurred mainly in the northern region of the country. During this period, we calculated an increase in the total ecosystem services value (ESV) in Nigeria from 665.93 billion (2007 US) in 2010, 97.38% of which was contributed by cultivated land. The value of provisioning services increased while regulation, support, recreation and culture services decreased, amongst which, water regulation (-11.01%), gas regulation (-7.13%), cultural (- 4.84%) and climate regulation (-4.3%) ecosystem functions are estimated as the most impacted. The increase in the total ESV in Nigeria associated with the huge increase in ecosystem services clue to cultivated land expansion may make land-use changes (i.e. the ever-increasing agricultural expansion in Nigeria) appear economically profitable. However, continuous loss of services such as climate and water regulation that are largely provided by the natural ecosystems can result in huge economic losses that may exceed the apparent gains from cultivated land development. Therefore, we advocate that the conservation of the natural ecosystem should be a priority in future land-use management in Nigeria, a country highly vulnerable to climate change and incessantly impacted by natural disasters such as flooding. (C) 2013 Elsevier B.V. All rights reserved
Seasonal and interannual dynamics of soil microbial biomass and available nitrogen in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China
No full textSoil microbial activity varies seasonally in frozen alpine soils during cold seasons and plays a crucial role in available N pool accumulation in soil. The intra- and interannual patterns of microbial and nutrient dynamics reflect the influences of changing weather factors, and thus provide important insights into the biogeochemical cycles and ecological functions of ecosystems. We documented the seasonal and interannual dynamics of soil microbial and available N in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China, between April 2011 and October 2013. Soil was collected in the middle of each month and analyzed for water content, microbial biomass C (MBC) and N (MBN), dissolved organic C and N, and inorganic N. Soil microbial community composition was measured by the dilutionplate method. Fungi and actinomycetes dominated the microbial community during the nongrowing seasons, and the proportion of bacteria increased considerably during the early growing seasons. Trends of consistently increasing MBC and available N pools were observed during the nongrowing seasons. MBC sharply declined during soil thaw and was accompanied by a peak in available N pool. Induced by changes in soil temperatures, significant shifts in the structures and functions of microbial communities were observed during the winter-spring transition and largely contributed to microbial reduction. The divergent seasonal dynamics of different N forms showed a complementary nutrient supply pattern during the growing season. Similarities between the interannual dynamics of microbial biomass and available N pools were observed, and soil temperature and water conditions were the primary environmental factors driving interannual fluctuations. Owing to the changes in climate, seasonal soil microbial activities and nutrient supply patterns are expected to change further, and these changes may have crucial implications for the productivity and biodiversity of alpine ecosystems
A Taxonomic Revision of Photinia integrifolia (Rosaceae)
No full textTaxonomic revision of a single species complex of Photinia integrifolia (Rosaceae) is accomplished during the revision of the genus Photinia sensu stricto. The study is based on the protologues and type specimens deposited in relevant herbaria. Thirty-two names are recorded for a single species. Five names are proposed as new synonyms, six lectotypes are designated, two names are identified as nomen nudum and three names are considered to be illegitimate. Taxonomic notes with type specimens, locality, and distribution for each taxon are provided
Organocatalyzed Asymmetric Dearomative Aza-Michael/Michael Addition Cascade of 2-Nitrobenzofurans and 2-Nitrobenzothiophenes with 2-Aminochalcones
No full textAn organocatalyzed dearomative aza-Michael/Michael addition cascade of 2-nitrobenzofurans and 2-nitrobenzothiophenes with 2-aminochalcones has been developed, opening a new channel to access a series of optically active tetrahydrobenzofuro[3,2-b]quinolines and tetrahydrobenzo [4,5]thieno[3,2-b]quinolines bearing three contiguous stereocenters with excellent diastereo- and enantioselectivities (all cases >20:1 dr, up to 99% ee). This study features the first asymmetric dearomative cascade reaction of 2-nitrobenzofurans and 2-nitrobenzothiophenes beginning with aza-Michael addition. The potential applications of the methodology were demonstrated by the preparative-scale experiment and the versatile transformations of the products
Assessment of frozen ground organic carbon pool on the Qinghai-Tibet Plateau
No full textPurposeUnder rapid climate change, soil organic carbon (SOC) dynamic in frozen ground may significantly influence terrestrial carbon cycles. The aim of this study was to investigate the storage, spatial patterns, and influencing factors of SOC in frozen ground on the Qinghai-Tibet Plateau, which known as the earth's Third Pole.Materials and methodsUsing the observed edaphic data from China's Second National Soil Survey, we estimated the SOC storage (SOCS) of frozen ground (including permafrost, seasonally, and short time frozen ground) on the plateau with a depth of 0-3m. Furthermore, the effect of vegetation and climate factors on spatial variance of SOC density (SOCD) was analyzed.Results and discussionThe SOCD decreased from the southeastern to the northwestern part of the plateau, and increased with shorten of freezing duration. SOCS of permafrost, seasonally, and short time frozen ground were calculated as 40.9 (34.2-47.6), 26.7 (24.1-29.4), and 6 (5.6-6.4)Pg, making a total of 73.6 (63.9-83.3)Pg in 0-3m depth on the plateau. Normalized difference vegetation index and mean annual precipitation could significantly affect the spatial distribution of SOC in permafrost and seasonally frozen ground.ConclusionsThe soil in plateau frozen ground contained substantial organic carbon, which could be affected by plant and climate variables. However, the heterogeneous landform may make the fate of carbon more complicated in the future
Leeches-Inspired Hydrogel-Elastomer Integration Materials
No full textInspired by the functions of leeches, for the first time homogeneous materials integrating hydrogels and elastomers were achieved by free radical polymerization. 2-Methoxyethyl acrylate (MEA) was used as elastomer monomer and Pluronics functionalized with vinyl groups acted as cross-linkers to impart the hydrogel property to the materials. The resulting Pluronic/PMEA gels possess a swelling ratio of about 210% and good water-retaining ability. Compression tests of Pluronic/PMEA gels at swelling equilibrium state show a stress up to 1.6 MPa under 85% strain. The gels act as elastomer after dehydration. Uniaxial tensile fracture stress and the elongation reached 1200 kPa and 500%, respectively, and compression stress was above 22 MPa. Furthermore, the Pluronic/PMEA gels also show self-healing properties. Owing to the excellent mechanical performance in both wet and dry conditions, this hydrogel-elastomer integrated material may have potential applications in tissue engineering, soft robotics, and biomedical devices
Assessment of the antitumor activity of a cyclopalladated ferrocene compound assisted by a dual-targeting drug delivery system
No full textOne cyclopalladated ferrocene compound CP was synthesized, which showed a good cell cytotoxicity. Assisted by a dual-targeting drug delivery system, the anticancer activity of CP to MDA-MB-468 remained unchanged, but the toxicity to non-tumorigenic cell line NIH3T3 was remarkably reduced. This provided a new path for the development of cyclopalladated ferrocene as an antitumor drug candidate
A new species of the genus Leptolalax (Anura, Megophryidae) from Hunan, China
No full textA new species, Leptolalax mangshanensis sp. nov., is described from the Mangshan National Nature Reserve, in Hunan Province, China. The new species is genetically similar to Leptolalax liui, and morphologically similar to Leptolalax maoershanensis. Morphological characteristics that distinguish the new species from its congeners are a small body size (snout-vent length, SVL, 22.2 mm-27.8 mm in 27 adult males, and 30.2 mm in one adult female); nearly smooth dorsal skin with some small, orange, tubercles and irregular, dark brown stripes, throat and belly scattered with white speckles, weak lateral fringes on toes and rudimentary toe webbing; indistinct longitudinal ridges under toes, and not interrupted at the articulations, iris bicolored with bright orange in the upper half and greyish cream in the lower half The new species is widely distributed in montane evergreen secondary forests and small bamboo forests in Mangshan Nature Reserve, at altitudes between 500-1600 m a.s.l