刺梨白粉病拮抗菌的筛选及其抑菌机制初探

为筛选出对刺梨白粉病具有良好抑制作用的拮抗菌,从健康刺梨及其根系土壤进行微生物分离,以刺梨白粉病病原菌(Sphaerotheca pannosa)为靶标菌株,采用叶盘法对拮抗菌进行筛选,通过形态学、生理生化特征以及16S rRNA对筛选的拮抗菌进行鉴定,测定其OD值绘制生长曲线,并探究拮抗菌对病原菌孢子萌发和菌丝的影响及其产酶情况。结果表明:共分离得到48株细菌,其中JK-6和JK-32具有显著抑制作用,经鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)和空气芽孢杆菌(Bacillus aerius),对刺梨白粉病的防治效果达到了60%和57%;拮抗菌作用下致使病原菌的孢子在萌发过程中发生异常膨大现象,菌丝表面变得粗糙、膨大、缠绕和融断;产酶情况表明两株拮抗菌均可产生蛋白酶、纤维素酶以及果胶酶。为刺梨白粉病的生物防治提供了理论基础,具有进一步研究价值。     

肉桂醛对乳清浓缩蛋白微胶囊品质的影响

为提高乳清浓缩蛋白（Whey protein concentrates, WPC）微胶囊的稳定性和包封率,利用肉桂醛（Cinnamaldehyde,CA）修饰WPC稳定的微胶囊界面。通过粒径、包封率、含水量、溶解性和微观结构等优化微胶囊的制备工艺,评价添加CA对WPC微胶囊品质的影响。结果表明,WPC浓度为5%,油相含量为5%时,添加1% CA的微胶囊包封率高达92.12%,而不添加CA的微胶囊包封率仅为55.68%。添加CA使微胶囊饱满圆润,表面致密光滑,能提高低油含量并稳定高油含量微胶囊的包封率,在一定程度改善其溶解特性,为蛋白微胶囊及其相关功能产品的开发提供信息。     

Effect of ultrasound treatment on properties of gluten-based film

Gluten films obtained in acid conditions display some protein dispersion difficulties. Ultrasound treatment (UT) could represent an interesting strategy for improving gluten film appearance. Different UT exposure times were applied to film-forming dispersion. The aim of this work was to investigate the effect of ultrasound treatment on gluten-based films at molecular and mesoscopic levels. Distribution in gliadin and glutenins was determined with SE-HPLC. The UT improved protein dispersion and final film appearance. Sonication did not lead to large changes in various gluten fractions, which suggests absence of important protein breakdown at the molecular level. Gluten showed high tolerance to UT. Surface properties of untreated and treated films were investigated by contact angle measurement: sonication promoted hydrophilic surface properties.Industrial relevanceBio-based packaging has been receiving increasing attention in view of its beneficial impact on the environment. Among proteins, gluten resulted as a very interesting film-forming material. Gluten films prepared in acid conditions showed problems in protein dispersion. Sonication represents a physical strategy which allowed us to obtain gluten-based films without the addition of chemical additives, such as sodium sulphite.     

蓝莓果渣花色苷大孔树脂纯化工艺研究

以蓝莓果渣为原料,利用大孔树脂分离纯化蓝莓果渣花色苷。对比了D101和AB-8两种不同极性的大孔树脂静态吸附和解吸效果。结果表明,AB-8型大孔树脂吸附率和解吸率分别为88.5%、64.7%;D101型大孔树脂吸附率和解吸率分别为86.7%、61.2%,AB-8型大孔树脂吸附率和解吸率均优于D101型大孔树脂,故选用AB-8型大孔树脂对蓝莓果渣进行纯化试验。AB-8型大孔树脂最佳吸附和解吸条件为吸附平衡时间4 h,解吸平衡时间4 h,花色苷溶液pH 3.0,解吸液pH 3.0,解吸液乙醇体积分数60%,上样质量浓度1 mg/mL,上样流速1 mL/min,洗脱流速1 mL/min。纯化后蓝莓果渣花色苷色价约为纯化前的3倍,糖和蛋白质等杂质大幅降低,纯度有了较大提高。     

微生物菌种选育中基因组重排技术应用的研究进展

基因组重排(genome shuffling)技术是通过传统诱变育种结合原生质体融合技术开发出的一种新型微生物菌种选育和改良技术,具有易操作、效率高和适用广等特点。本文对基因组重排技术的原理、操作过程及其在增加次生代谢产物产量、增强菌株耐受性和提高底物利用能力等方面的应用进行了综述。     

Optically tuneable broadband terahertz metamaterials using photosensitive semiconductor material

We present optically tuneable broadband terahertz metamaterials consisting of photosensitive semiconductor material. The characteristics of semiconductor materials are very important for terahertz functional devices, which is strongly dependent on the photoexcited carriers in semiconductor materials. Based on the model of the generation of the carriers in semiconductor materials, the tuneability of the resonance frequency and resonance strength in terahertz metamaterials under the femtosecond laser pulse has been analysed. The experimental results of the transmissivities of several bare semiconductor materials show that GaAs semiconductor could be a potential candidate for broadband terahertz functional devices design. Moreover, the simulation results of the resonance frequency increase with the increase of the laser fluence, whereas the resonance strength near the resonance frequency is significantly weakened with the increase of the laser fluence. Meanwhile, the modulation depth can be reached approximately 90% at 1.24 THz. Our proposed broadband tuneable terahertz metamaterials have numerous potential applications, including terahertz modulator, absorber and switches.     

Dispersion-free highly accurate color recognition using excitonic 2D materials and machine learning

Dispersion is accepted as a fundamental step required for analyzing broadband light. The recognition of color by the human eye, its digital reproduction by a camera, or detailed analysis by a spectrometer all utilize dispersion; it is also an inherent component of color detection and machine vision. Here, we present a device (called artificial eye or, A-Eye) that accurately recognizes and reproduces tested colors, without any spectral dispersion. Instead, A-Eye uses N = 3–12 transmissive windows each with unique spectral features resulting from the broadband transmittance and excitonic peak-features of 2D transition metal dichalcogenides. Colored light passing through (and modified by) these windows and incident on a single photodetector generated different photocurrents, and these were used to create a reference database (training set) for 1337 “seen” and 0.55 million synthesized “unseen” colors. By “looking” at test colors modified by these windows, A-Eye can accurately recognize and reproduce “seen” colors with zero deviation from their original spectra and “unseen” colors with only ∼1 % median deviation, using the k-NN algorithm. A-Eye can continuously improve color estimation by adding any corrected guesses to its training database. A-Eye’s accurate color recognition dispels the notion that dispersion of colors is a prerequisite for color identification and paves the way for ultra-reliable color-recognition by machines with reduced engineering complexity.     

Tumor extracellular matrix-targeted nanoscavengers reverse suppressive microenvironment for cocktail therapy

Extracellular matrix (ECM) is not only a natural bulwark to shield solid tumor cells from therapeutic agents and cytotoxic T lymphocytes (CTLs), but also one of the key factors that cause tumor hypoxic environment, severely hindering photodynamic reactions and immune responses. In this work, multifunctional nanoscavengers (ECMT NS) consisting of digestive enzyme chymotrypsin, catalase, calcium peroxide nanoparticles, photosensitizer chlorin e6, and tumor ECM-targeting CLT1 peptide are rationally designed with several benefits for enhanced cocktail calcium ion/photodynamic/immune therapy. The scavengers can effectively “clear” tumor ECM via digestive proteolytic enzyme- and reactive oxygen species-mediated pathways, deepening tumor penetration of the scavengers and CTLs. Thanks to the ECM destruction and oxygen self-supply capability of ECMT NS, the hypoxia in tumors is attenuated, thus improving photodynamic therapeutic efficiency and downregulating immunosuppressive factors. Moreover, the combination of calcium ion overload and photodynamic therapy enriches damage-associated molecular patterns, which promotes CTL activation to inhibit abscopal tumor growth and lung metastasis. The presented ECM destruction strategy provides a solution to overcome the tumor suppressive microenvironment.