Browsing by Author "Tian, J"

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    In situ synthesis of DNA microarray on functionalized cyclic olefin copolymer substrate.
    (ACS Appl Mater Interfaces, 2010-02) Saaem, I; Ma, K; Marchi, A; LaBean, T; Tian, J
    Thermoplastic materials such as cyclic-olefin copolymers (COC) provide a versatile and cost-effective alternative to the traditional glass or silicon substrate for rapid prototyping and industrial scale fabrication of microdevices. To extend the utility of COC as an effective microarray substrate, we developed a new method that enabled for the first time in situ synthesis of DNA oligonucleotide microarrays on the COC substrate. To achieve high-quality DNA synthesis, a SiO(2) thin film array was prepatterned on the inert and hydrophobic COC surface using RF sputtering technique. The subsequent in situ DNA synthesis was confined to the surface of the prepatterned hydrophilic SiO(2) thin film features by precision delivery of the phosphoramidite chemistry using an inkjet DNA synthesizer. The in situ SiO(2)-COC DNA microarray demonstrated superior quality and stability in hybridization assays and thermal cycling reactions. Furthermore, we demonstrate that pools of high-quality mixed-oligos could be cleaved off the SiO(2)-COC microarrays and used directly for construction of DNA origami nanostructures. It is believed that this method will not only enable synthesis of high-quality and low-cost COC DNA microarrays but also provide a basis for further development of integrated microfluidics microarrays for a broad range of bioanalytical and biofabrication applications.
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    Response of fungal communities to fire in a subtropical peatland
    (Plant and Soil, 2021-09-01) Tian, J; Wang, H; Vilgalys, R; Ho, M; Flanagan, N; Richardson, CJ
    Purpose: Wildfire, an increasing disturbance in peatlands, could dramatically change carbon stocks and reshape plant/microbial communities, with long-lasting effects on peatland functions. Soil fungi are important in controlling the belowground carbon and nutrient cycling in peatlands; however, the impact of altered fire regimes on these fungi is still unclear. Methods: We assessed fungal abundance, composition, and diversity across four soil depths (0–5 cm, 6–10 cm, 11–15 cm, 16–20 cm) under low-severity and high-severity fire in a subtropical peatland in the southeastern USA. Results: Low-severity fire significantly increased fungal Shannon diversity and saprotrophic fungi in the 0–5 cm soil layer immediately after fire and then retracted within 2 years. This pattern was not observed below 5 cm soils. The dominant fungal class − Archaeorhizomycetes declined initially and then returned to pre-low-severity fires levels at 0–5 cm depths. Time since low-severity fire was a primary driver of fungal composition in the 0–10 cm soil depth, while spatial distance among sites affected the deeper soils (11–20 cm). The fungal Shannon diversity failed to recover in the unburned state even 30 years after high-severity fire, especially in 6–20 cm soil layers. Stratification patterns of the fungal community were diminished by high-severity fire. Soil properties (either phenolics or carbon) were the primary drivers in shaping fungal community reassembly after high-severity fire across all soil depths. Conclusion: Collectively, the fungal communities seem to be highly resilient to low-severity fire, but not to high-severity fire in the shrub-dominated coastal peatlands.
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    Vegetation and microbes interact to preserve carbon in many wooded peatlands
    (Communications Earth & Environment, 2021-12) Wang, H; Tian, J; Chen, H; Ho, M; Vilgalys, R; Bu, ZJ; Liu, X; Richardson, CJ
    AbstractPeatlands have persisted as massive carbon sinks over millennia, even during past periods of climate change. The commonly accepted theory of abiotic controls (mainly anoxia and low temperature) over carbon decomposition cannot fully explain how vast low-latitude shrub/tree dominated (wooded) peatlands consistently accrete peat under warm and seasonally unsaturated conditions. Here we show, by comparing the composition and ecological traits of microbes between Sphagnum- and shrub-dominated peatlands, that slow-growing microbes decisively dominate the studied shrub-dominated peatlands, concomitant with plant-induced increases in highly recalcitrant carbon and phenolics. The slow-growing microbes metabolize organic matter thirty times slower than the fast-growing microbes that dominate our Sphagnum-dominated site. We suggest that the high-phenolic shrub/tree induced shifts in microbial composition may compensate for positive effects of temperature and/or drought on metabolism over time in peatlands. This biotic self-sustaining process that modulates abiotic controls on carbon cycling may improve projections of long-term, climate-carbon feedbacks in peatlands.