低温原子力显微镜(cryogenic atomic force microscope,cryo-AFM)能够克服常温原子力显微镜(atomic force microscope,AFM)的诸多局限从而可以在生物大分子样品中获得更高分辨率的结构信息。然而,如何获得接近分子天然状态的洁净样品依...低温原子力显微镜(cryogenic atomic force microscope,cryo-AFM)能够克服常温原子力显微镜(atomic force microscope,AFM)的诸多局限从而可以在生物大分子样品中获得更高分辨率的结构信息。然而,如何获得接近分子天然状态的洁净样品依然是cryo-AFM面临的挑战之一,也是制约cryo-AFM进一步应用于更多不同生物分子结构解析的主要因素之一。针对这一问题,本研究提出了一种新的适用于cryo-AFM样品制备的方法,并使用人类补体分子(complement 1q,C1q)作为典型样品进行验证,实验结果表明使用本研究所提出的样品制备方法能够快速有效地制作出适用于低温原子力显微镜成像的洁净样品且同时能保证样品更接近天然结构。本研究预计该样品制备方法不仅适用于cryo-AFM,也将为其它真空或者低温下的生物大分子结构研究技术的样品制备提供借鉴。展开更多
To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jer...To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.展开更多
文摘低温原子力显微镜(cryogenic atomic force microscope,cryo-AFM)能够克服常温原子力显微镜(atomic force microscope,AFM)的诸多局限从而可以在生物大分子样品中获得更高分辨率的结构信息。然而,如何获得接近分子天然状态的洁净样品依然是cryo-AFM面临的挑战之一,也是制约cryo-AFM进一步应用于更多不同生物分子结构解析的主要因素之一。针对这一问题,本研究提出了一种新的适用于cryo-AFM样品制备的方法,并使用人类补体分子(complement 1q,C1q)作为典型样品进行验证,实验结果表明使用本研究所提出的样品制备方法能够快速有效地制作出适用于低温原子力显微镜成像的洁净样品且同时能保证样品更接近天然结构。本研究预计该样品制备方法不仅适用于cryo-AFM,也将为其它真空或者低温下的生物大分子结构研究技术的样品制备提供借鉴。
文摘To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.
