BR-Mediated Protein S-Nitrosylation Alleviated Low-Temperature Stress in Mini Chinese Cabbage (Brassica rapa ssp. pekinensis)

Brassinosteroids (BRs), a novel plant hormone, are widely involved in plant growth and stress response processes. Nitric oxide (NO), as an important gas signaling molecule, can regulate target protein activity, subcellular localization and function in response to various stresses through post-translational S-nitrosylation modifications. However, the relationship between BR and NO in alleviating low-temperature stress of mini Chinese cabbage remains unclear. The hydroponic experiment combined with the pharmacological and molecular biological method was conducted to study the alleviating mechanism of BR at low temperature in mini Chinese cabbage. The results showed that low temperature inhibited the growth of mini Chinese cabbage seedlings, as evidenced by dwarf plants and yellow leaves. Treatment with 0.05 mg/L BR and 50 µM NO donor S-nitrosoglutathione (GSNO) significantly increased the leaf area, stem diameter, chlorophyll content, dry and fresh weight and proline content. Meanwhile, the malondialdehyde (MDA) content in 0.05 mg/L BR- and 50 µM GSNO-treated leaves were significantly lower than those in other treated leaves under low-temperature conditions. In addition, BR and GSNO applications induced an increase in NO and S-nitrosothiol (SNO) levels in vivo under low-temperature stress. Similarly, spraying BR after the elimination of NO also increased the level of S-nitrosylation in vivo, while spraying GSNO after inhibiting BR biosynthesis decreased the level of NO and SNO in vivo. In contrast, the S-nitrosoglutathione reductase (BrGSNOR) relative expression level and GSNOR enzyme activity were downregulated and inhibited by BR treatment, GSNO treatment and spraying BR after NO clearance, while the relative expression level of BrGSNOR was upregulated and GSNOR enzyme activity was also increased when spraying GSNO after inhibiting BR synthesis. Meanwhile, the biotin switch assay showed that exogenous BR increased the level of total nitrosylated protein in vivo under low-temperature stress. These results suggested that BR might act as an upstream signal of NO, induced the increase of NO content in vivo and then induced the protein S-nitrosylation modification to alleviate the damage of mini Chinese cabbage seedlings under low-temperature stress.     

针对鳊鱼新鲜度的气敏传感器筛选与阵列构建

鱼体在贮藏过程中新鲜度下降,散发出一系列特征气味。研究采用气质联用（GC-MS）对4℃恒温贮藏的鳊鱼样本进行检测,分析样本从新鲜到腐败的特征性挥发物质;根据这些物质,筛选对应的传感器组成阵列;采用基于该阵列的电子鼻系统对不同贮藏期的鳊鱼样本进行检测,验证该阵列评价鱼新鲜度的有效性。结果显示,鳊鱼样本在腐败过程中的特征性挥发物质为:醇、醛酮、烃、苯、酸以及含氮、含硫物质。基于这些物质所筛选的传感器为:TGS822、TGS2620、TGS880、TGS813、TGS816、TGS832、TGS831、TGS2610、TGS2611、TGS2600、TGS826和TGS825。采用基于该传感器阵列的电子鼻系统检测不同贮藏期的鳊鱼样本。对采集的数据作主成分分析和Fisher判别分析,其前三个主成分贡献率为95.6%,样本在不同贮藏期区分性好。研究表明所采用的传感器筛选方法是行之有效的,依此所建立的传感器阵列与电子鼻系统用于判别鱼新鲜度响应快、精度高。      

Identification and Characterization of PSEUDO-RESPONSE REGULATOR (PRR) 1a and 1b Genes by CRISPR/Cas9-Targeted Mutagenesis in Chinese Cabbage (Brassica rapa L.)

The CRISPR/Cas9 site-directed gene-editing system offers great advantages for identifying gene function and crop improvement. The circadian clock measures and conveys day length information to control rhythmic hypocotyl growth in photoperiodic conditions, to achieve optimal fitness, but operates through largely unknown mechanisms. Here, we generated core circadian clock evening components, Brassica rapa PSEUDO-RESPONSE REGULATOR (BrPRR) 1a, 1b, and 1ab (both 1a and 1b double knockout) mutants, using CRISPR/Cas9 genome editing in Chinese cabbage, where 9–16 genetic edited lines of each mutant were obtained. The targeted deep sequencing showed that each mutant had 2–4 different mutation types at the target sites in the BrPRR1a and BrPRR1b genes. To identify the functions of BrPRR1a and 1b genes, hypocotyl length, and mRNA and protein levels of core circadian clock morning components, BrCCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) and BrLHY (LATE ELONGATED HYPOCOTYL) a and b were examined under light/dark cycles and continuous light conditions. The BrPRR1a and 1ab double mutants showed longer hypocotyls, lower core circadian clock morning component mRNA and protein levels, and a shorter circadian rhythm than wildtype (WT). On the other hand, the BrPRR1b mutant was not significantly different from WT. These results suggested that two paralogous genes may not be associated with the same regulatory function in Chinese cabbage. Taken together, our results demonstrated that CRISPR/Cas9 is an efficient tool for achieving targeted genome modifications and elucidating the biological functions of circadian clock genes in B. rapa, for both breeding and improvement.     

基于可视传感器阵列的鳊鱼新鲜度评价模型研究

目的 建立基于可视传感器阵列的鳊鱼新鲜度评价模型。方法 研究采用可视传感阵列与鱼体进行无接触式反应, 提取阵列反应前后的颜色变化信息来表征鱼的气味特征; 同时根据行业标准SC/T3032-2007测得表征鱼新鲜度的挥发性盐基氮(TVB-N)含量; 将可视传感技术所得的特征信息与TVB-N指标含量进行关联, 分别建立基于可视传感技术鱼新鲜度评价的定性模型BP神经网络和联合间隔偏最小二乘法(siPLS)定量模型。结果 BP神经网络模型精度较高, 训练集正确率为86.79%, 预测集正确率为86.43%; siPLS模型次之, 模型校正集和预测集的正确率分别为82.52%和80.67%。结论 可视传感器新技术所测得指标与TVB-N相关性较大, 可快速预测出鱼在储藏期间TVB-N的变化从而能够快速、无损地评价鱼类新鲜度。     

不同腌制方式对风干鳊鱼理化指标的影响

为探讨不同腌制方式对风干鳊鱼理化指标的影响,以鳊鱼为原料,分别研究干腌、湿腌、混合腌制三种腌制方式对风干鳊鱼加工过程中鱼肉的含盐量、含水量、TBA、p H、硬度和感官评价的影响。结果表明,三种腌制方式鳊鱼鱼肉的含水量均呈现下降的趋势,其中干腌含水量下降速率最快;含盐量均呈现上升的趋势,腌制结束后各种腌制方式的含盐量差异显著(p<0.05),干腌含盐量升高的速率大于其他两种腌制方式,其最终含盐量为7.80%;TBA均呈现上升的趋势,在腌制结束后,干腌TBA显著高于湿腌和混合腌制(p<0.05),其最终TBA值达到5.64 mg/kg;硬度均呈现先下降后上升的趋势,但差异不显著(p>0.05);p H在加工过程中变化不大;三种腌制方式干腌的感官评分最高,其次是混合腌制、湿腌,三种腌制方式的感官评分分别是91.29、86.24、84.50。综合比较干腌腌制的风干鳊鱼在腌制速度和产品风味方面优于湿腌和混合腌制。      

基于鱼类需求的息县枢纽工程闸下河段环境流量研究

针对水利工程建成运行后对下游河段流量过程变化造成的鱼类原有栖息地面积减小和质量降低的潜在生态问题,对拟建息县枢纽工程闸下4.9 km河段内采用栖息地模拟法进行环境流量研究。采用MIKE数值模拟与HSI栖息地模型结合的方法,通过分析自然状态下研究河段的水流特性及鱼类栖息地现状,讨论了在不同生命期不同流量对鱼类栖息地的影响,确定了适宜环境流量范围,为水利工程建设后水生生物栖息地保护提供理论和方法指导。     

Glucosinolate content of Brassica vegetables-Chinese cabbages Pe-tsai (Brassica pekinensis) and Pak-choi (Brassica chinensis)

The glucosinolate content of 19 cultivars of pe-tsai and three cultivars of pak-choi Chinese cabbage (Brassica pekinensis Lour) Rupr and (Brassica chinensis L, respectively) has been determined using high performance liquid chromatography. The levels of total glucosinolates were 0.097-0.337 g kg^?1 fresh weight (mean 0.198) in pe-tsai and 0.39-0.704 g kg^?1 (mean 0.534) in pak-choi. The main components present were (2-hydroxybut-3-enyl-progoitrin), but-3-enyl- (gluconapin), 5-methylsulphinylpentyl- (glucoalyssin) and pent-4-enyl (glucobrassicanapin) glucosinolates, respectively. In comparison with other UK brassicas and American cultivars of Chinese cabbage, both the UK-grown pak-choi and pe-tsai are low in glucosinolates.     

美拉德反应基液——鳊鱼蛋白酶解液的制备

研究以鳊鱼蛋白为原料,经过酶解反应,以期获得风味良好的美拉德反应基液。通过风味蛋白酶与其它蛋白酶复配筛选组合,综合考察影响酶解反应的4个因素:温度、时间、pH和酶添加量,以水解度(DH)为响应值,采用Box-Benhnken响应面分析法确定最佳反应条件。研究结果表明,以风味蛋白酶和复合蛋白酶(3:1)复配的组合水解度最高,酶解反应条件为:温度51.5℃,时间5.7h,pH7.7,酶添加量0.80%,水解度可达79.46%。在该条件下制得的酶解液腥味弱,苦味值低,有淡淡的鱼香味,可以作为美拉德反应的基液。     

白菜中二硫代磷酸酯类有机磷农药降解动力学研究

培养8 叶期无菌白菜幼苗,添加5 种二硫代磷酸酯类有机磷农药（马拉硫磷、乐果、甲拌磷、乙拌磷及特丁硫磷）,用气相色谱及液相色谱-质谱联用法检测二硫代磷酸酯类农药及O,O-二甲基二硫代磷酸酯残留量。结果表明：二硫代磷酸酯类农药的含量在实验过程中呈减少的趋势,农药在样本培养过程被逐渐降解,10 d内降解水平为13.4%～65.0%,无菌苗添加药物组降解速率明显低于正常培养添加药物对照组。使用一级反应动力学模型对农药代谢动力学进行评价,无菌条件下马拉硫磷降解速率最快,降解速率常数为0.034 67,降解半衰期为19.9 d,特丁硫磷降解速率常数最小,降解速率常数为0.007 17,降解半衰期为96.7 d,乐果、甲拌磷及乙拌磷相对稳定,但降解动力学差别较大。     

农杆菌介导法获得抗病毒病转基因大白菜

为获得抗芜菁花叶病毒病的大白菜植株,用携带TuMV-cp基因的农杆菌R1000和EHA105转化大白菜子叶和下胚轴,PCR、PCR-Southern检测证实TuMV-cp基因已导入并整合到大白菜的基因组中.RT-PCR检测表明TuMV-cp在转录水平上获得了稳定表达.TuMV-cp基因在转基因植株T1代中获得了稳定的遗传.抗病性鉴定结果表明转基因植株T1代较非转基因植株对TuMV的抗性增强,获得了抗病毒病的转基因大白菜植株.