Institutional Repository of Chengdu Institute of Biology, CAS
Not a member yet
6513 research outputs found
Sort by
Study on the synthesis of sulfenylindoles with Dess -Martin periodinane - promoted
No full text目的建立简单、高效制备吲哚硫醚类化合物的方法。方法以Dess- Martin试剂(DMP)为促进剂,异丙醇为溶剂,在室温下反应15 min,促进硫醇和吲哚反应来制备吲哚硫醚类化合物。结果和讨论合成了一系列吲哚硫醚类化合物,结构经~1HNMR、~(13)CNMR和HR- MS鉴定。该反应具有原子经济性好、反应条件温和、反应时间短等优点
First detection of foot-and-mouth disease virus O/ME-SA/Ind2001 in China
No full textFoot-and-mouth disease (FMD) is endemic in China and is predominantly due to foot-and-mouth disease virus (FMDV) serotype O Mya-98 lineage. In recent years, FMDV O/ME-SA/Ind2001 lineage has spread from the Indian subcontinent to South-East Asia, Middle East and Africa, which may pose potential threats for future trans-regional livestock movements. In this study, we identified the appearance of FMDV O/ME-SA/Ind2001 in China; the first time that this virus lineage has been found there. Sequencing and phylogenetic analysis of VP1 sequences revealed that this newly determined strain belongs to O/ME-SA/Ind2001 sublineage d and is closely related to strains that have caused recent outbreaks of FMD in Nepal, Myanmar, Russia and South Korea. The results suggest extensive movements of the current O/ME-SA/Ind2001 sublineage d viruses and provide essential information for an effective national FMDV control programme in China
Effects of urease and nitrification inhibitors on nitrous oxide emissions and nitrifying/denitrifying microbial communities in a rainfed maize soil: A 6-year field observation
No full textApplication of the inhibitor-amended nitrogen fertilizers is a recommended method for reducing agricultural nitrous oxide (N2O) emission. However, the potential impacts of these inhibitors on soil environments still needs to be evaluated using long-term experiments. Through a 6-year field observation, the effects of combined application of a nitrification inhibitor (dicyandiamide, DCD) and a urease inhibitor (hydroquinone, HQ) on N2O emission, as well as soil ammonia oxidizers and denitrifiers in a maize (Zea mays L.) field in Northeast China were investigated. The results showed that annual soil N2O emissions were 0.466, 1.021 and 0.874 kg N2O-N ha(-1) for N0 fertilizer treatment (CK), Urea treatment (U) and Urea + DCD + HQ treatment (UDH), respectively. A significant linear correlation was found between the N2O accumulation in the first month after fertilizer application and the short-term precipitation (i.e., a period from 10 days before to 20 days after fertilizer application). The N2O emissions in the freeze-thaw period accounted for up to 42.5% of the year-round N2O emissions. The remarkable fluctuations of annual N2O emissions were observed (their coefficients of variation were 68.3%, 77.7% and 71.2% for CK, U and UDH treatments, respectively); these fluctuations were mainly attributed to the precipitation. The averaged N2O emission factors (EF) (0.308% and 0.227% for U and UDH treatments, respectively) were far less than the default mean EF of 1% proposed by (IPCC, 2006). An averaged N2O mitigation of 26.4% was fulfilled by UDH application. The results of quantitative PCR for soil nitrification and denitrification gene copy numbers measurement showed that UDH treatment significantly decreased the ammonia oxidation bacteria (AOB) amoA gene copy numbers by 74% on the 10th day after UDH application. No significant effects of combined application of DCD and HQ on microbial denitrification functional gene abundance were observed
Identification of monocot flora using pollen features through scanning electron microscopy
No full textPollen used to track structural and functional evolution in plants as well as to investigate the problems relative to plant classification. Pollen characters including ornamentation, shape, apertural pattern, pollen symmetry, colpus length, width, and margins used to detect the similarities and dissimilarities between genera and also species of the same genus. In this study pollen features of 20 monocot species belonging to 15 genera of the Amaryllidaceae, Asparagaceae, Iridaceae, Ixioliriaceae, Liliaceae, and Xanthorrhoeaceae were studied using scanning electron microscopy (SEM) and light microscopy (LM). In this study two species that is Zephyranthes citrina and Tulbaghia violacea were reported for the first time from Pakistan. Pollen grains were visualized with LM. Non-acetolyzed and acetolyzed pollen were examined using SEM. A taxonomic key was developed to highlight the variation in pollen features in order to make their systematic application for correct species identification
Effect of air-exposed biocathode on the performance of a Thauera-dominated membraneless single-chamber microbial fuel cell (SCMFC)
No full textTo investigate the effect of air-exposed biocathode (AEB) on the performance of single-chamber microbial fuel cell (SCMFC), wastewater quality, bioelectrochemical characteristics and the electrode biofilms were researched. It was demonstrated that exposing the biocathode to air was beneficial to nitrogen removal and current generation. In Test 1 of 95% MB, removal rates of ammonia, total nitrogen (TN) and chemical oxygen demand (COD) reached 99.34% +/- 0.11%, 99.34% +/- 0.10% and 90.79% +/- 0.12%, respectively. The nitrogen removal loading rates were 36.38 g N/m(3) /day. Meanwhile, current density and power density obtained at 0.7 A/m(3) and 104 mW/m(3) respectively. Further experiments on opencircuit (Test 2) and carbon source (Test 3) indicated that this high performance could be attributed to simultaneous biological nitrification/denitrification and aerobic denitrification, as well as bioelectrochemical denitrification. Results of community analysis demonstrated that both microbial community structures on the surface of the cathode and in the liquid of the chamber were different. The percentage of Thauera, identified as denitrifying bacteria, maintained at a high level of over 50% in water, but decreased gradually in the MB. Moreover, the genus Nitrosomonas, Alishewanella, Arcobacter and Rheinheimera were significantly enriched in the MB, which might contribute to both enhancement of nitrogen removal and electricity generation. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V
Temporal response of soil prokaryotic communities to acidification and alkalization under laboratory conditions
No full textSoil pH plays an important role in shaping the structure and diversity of prokaryotic community. Altered pH regimes may change prokaryotic community composition by selecting species or groups with different ecological strategies to optimize their fitness. However, it remains unresolved whether prokaryotic communities exhibit deterministic (phylogenetically conserved) or stochastic (phylogenetically overdispersed) responses to pH. In this study we investigated the responses of greenhouse gas emissions and prokaryotic community structure to pH using three-month incubation experiments by adjusting an artificial pH gradient from 4.5 to 8.5. We found decreasing OTUs richness after three months of incubation. Phylogenetic clustering of the prokaryotic community was observed at earlier incubation times whereas greater phylogenetic distance of the prokaryotic community was found at later incubation time. Our results evidenced differential responses of various soil bacterial taxa to the changes in pH. Relative abundances of bacterial phyla and classes of main ecological groups of soil prokaryotes, oligotrophs and copiotrophs, changed significantly along an artificial pH gradient at various incubation times. Relative abundance of Acidobacteria significantly increased with pH at the start of experiment, while opposite trend was observed after 90 days of incubation. In contrast, the relative abundance of Bacteroidetes showed opposite response as Acidobacteria to elevated pH gradient during various incubation time. Methane emissions increased with pH as well as with incubation time, but carbon dioxide and nitrous oxide only increased with incubation time
Reusable Xerogel Containing Quantum Dots with High Fluorescence Retention
No full textAlthough various analytical methods have been established based on quantum dots (QDs), most were conducted in solution, which is inadequate for storage/transportation and rapid analysis. Moreover, the potential environmental problems caused by abandoned QDs cannot be ignored. In this paper, a reusable xerogel containing CdTe with strong emission is established by introducing host-guest interactions between QDs and polymer matrix. This xerogel shows high QDs loading capacity without decrease or redshift in fluorescence (the maximum of loading is 50 wt % of the final xerogel), which benefits from the steric hindrance of beta-cyclodextrin (beta CD) molecules. Host-guest interactions immobilize QDs firmly, resulting in the excellent fluorescence retention of the xerogel. The good detecting performance and reusability mean this xerogel could be employed as a versatile analysis platform (for quantitative and qualitative analyses). In addition, the xerogel can be self-healed by the aid of water
Response of ammonium oxidizers to the application of nitrogen fertilizer in an alpine meadow on the Qinghai-Tibetan Plateau
No full textThe alpine meadows in Qinghai-Tibetan Plateau is an ecosystem sensitive to environmental changes. As part of a study on global climate change and the effects of N precipitation on soil microbiota, we fingerprinted ammonium oxidizing archaea (AOA) and bacteria (AOB) in relation to the N supplement in an alpine meadow in Qinghai Tibetan Plateau. The results showed that nutrient content in the studied soil was significantly varied in different months (sampling period) but not influenced by the N supplement rate. Long-term nitrogen input dramatically changed the abundance and community composition of the AOB but exerted no obvious effect on the AOA community in the tested soil. Significant differences in the abundance and composition of AOA were recorded in different months. Our findings implied that 1) the soil fertility and physicochemical features of the studied alpine meadows in Qinghai-Tibetan Plateau were stable even under the long-term high N supply; 2) AOB might be the active nitrifiers responding to the high N supply, while the AOA were the abundant and stable nitrifiers despite the N supply; 3) sampling periods mainly affected the abundance and community composition of the nitrifiers in the tested alpine meadow; and 4) the AOB in the studied area are psychrotrophs. Therefore, despite the enhancement of plant growth, high N supplements in the tested alpine meadow ecosystems might cause more pollution to water and air, which in turn contributes to global climate change
Functional and phylogenetic response of soil prokaryotic community under an artificial moisture gradient
No full textMoisture is recognized as a key factor shaping the structure of soil microbial community and its function in soil ecosystem. However, the temporal response patterns of soil microbes under various moisture regimes remain poorly understood. Therefore, the main objective of our study was to reveal how moisture regulates prokaryotic community structure, diversity, phylogenetic structure and finally how moisture regulates greenhouse gas emissions, as an indicator of microbial community function. We monitored prokaryotic community in soil incubated under an artificial moisture gradient for three months. We observed robust effects of both moisture gradient and incubation time on increased greenhouse gas emissions (methane, carbon dioxide and nitrous oxide). Furthermore, the moisture gradient as well as the incubation time exerted significant effects on species turnover of the soil prokaryotic community. In contrast, the artificial moisture gradient did not show any significant effects on prokaryotic alpha diversity. Alpha diversity of the soil prokaryotic community decreased significantly with incubation time. Different community assembly patterns were observed (based on both the mean nearest relatedness index (NRI) and nearest taxon index (NTI)). The mean NRI exhibited the dominance of stochastic factors, while the NTI indicated the dominance of deterministic factors. The prokaryotic communities in soils with less moisture tended to be controlled by stochastic factors, while prokaryotes in soils with higher moisture (60%) were controlled by deterministic factors. Relative abundances of oligotrophs and copiotrophs did not change significantly along the artificial moisture gradient, while the relative abundances of some prokaryotic taxa did vary significantly along the artificial moisture gradient
Mixed nitrifying bacteria culture under different temperature dropping strategies: Nitrification performance, activity, and community
No full textIn this study, the nitrification performance, metabolic activity, antioxidant enzyme activity as well as bacterial community of mixed nitrifying bacteria culture under different temperature dropping strategies [(#1) growth temperature kept at 20 degrees C; (#2) sharp1 decreased from 20 degrees C to 10 degrees C; (#3) growth at 20 degrees C for 6 days followed by sharp decrease to 10 degrees C; and (#4) gradual decreased from 20 degrees C to 10 degrees C] were evaluated. It was shown that acclimation at 20 degrees C for 6 days allowed to maintain better nitrification activity at 10 degrees C. The nitrite oxidation capacity of nitrifiers was significantly correlated with the relative light unit (RLU) (p<.05) and the fluctuation of superoxide dismutase (SOD) enzyme activity (p<.01). With serial #3 showed the highest RLU levels and the least SOD enzyme fluctuation as compared to serials #2 and #4. Throughout the experimental period, Nitrosospira and Nitrosomonas as well as Nitrospira were identified as the predominant ammonia-oxidizing bacteria (AOB) and nitrate-oxidizing bacteria (NOB). The dynamic change of AOB/NOB ratios and nitrification activity in serials #2-#4 demonstrated that AOB recovered better than NOB with long-term 10 degrees C exposure, and the nitrification performance was mainly limited by the nitrite oxidation capacity of NOB. Applying 6 days acclimation at 20 degrees C was beneficial for the mixed nitrifying bacteria culture to cope with low temperature (10 degrees C) stress, possibly due to the maintenance of metabolic activity, antioxidant enzyme activity stability as well as appropriate AOB/NOB ratio. (C) 2017 Elsevier Ltd. All rights reserved