根癌农杆菌介导的定点敲除技术在红色红曲菌中的应用

红曲菌(Monascus spp.)是一种重要的丝状真菌, 广泛应用于食品和医药领域中。目前, 由于对红曲菌遗传背景了解的很少, 因而对其重要功能基因的研究报道很少。本研究采用根癌农杆菌介导的转化技术对红色红曲菌(Monascus ruber)中推断的G-蛋白信号调节子mrfA基因的RGS功能域进行定点缺失研究, 探讨基于同源重组为基础的基因定点缺失技术在红曲菌基因功能鉴定中的可行性。构建的敲除载体pC805S左右同源臂长度分别为958 bp和824 bp, 将其转入受体菌M. ruber 中, 得到的138株转化子中, 有26株转化子发生了同源重组, 重组率达到18.8%。实验结果表明该技术作为红曲菌基因功能鉴定的方法是可行的。     

微生物黄色素的研究进展

对来源于微生物的天然黄色素的研究进行了详细概述, 尤其对红曲黄色素的生产、安全性以及黄色素的合成代谢机理研究进行了详细论述, 最后对红曲黄色素的应用前景及其未来研究重点进行了展望, 并对研究中存在的问题进行了分析。     

竹黄菌固态发酵竹红菌素条件的研究

研究了竹黄菌固体发酵培养生成竹红菌素过程中培养条件的影响。结果表明,竹黄菌生长及竹红菌素生成适宜的温度、pH分别为26℃、5．5—6。最佳的培养基物料厚度为5cm左右。固态发酵过程中最适的水份含量为50％。玉米粉是一种适宜的培养基基本组成。在以上发酵条件下竹红菌素产量为4mg/kg。     

Assessing leaf pigment content and activity with a reflectometer

This study explored reflectance indices sampled with a 'leaf reflectometer' as measures of pigment content for leaves of contrasting light history, developmental stage and functional type (herbaceous annual versus sclerophyllous evergreen). We employed three reflectance indices: a modified normalized difference vegetation index (NDVI), an index of chlorophyll content; the red/green reflectance ratio ( R _RED: R _GREEN), an index of anthocyanin content; and the change in photochemical reflectance index upon dark–light conversions (ΔPRI), an index of xanthophyll cycle pigment activity. In Helianthus annuus (sunflower), xanthophyll cycle pigment amounts were linearly related to growth light environment; leaves in full sun contained approximately twice the amount of xanthophyll cycle pigments as leaves in deep shade, and at midday a larger proportion of these pigments were in the photoprotective, de-epoxidized forms relative to shade leaves. Reflectance indices also revealed contrasting patterns of pigment development in leaves of contrasting structural types (annual versus evergreen). In H. annuus sun leaves, there was a remarkably rapid increase in amounts of both chlorophyll and xanthophyll cycle pigments along a leaf developmental sequence. This pattern contrasted with that of Quercus agrifolia (coast live oak, a sclerophyllous evergreen), which exhibited a gradual development of both chlorophyll and xanthophyll cycle pigments along with a pronounced peak of anthocyanin pigment content in newly expanding leaves. These temporal patterns of pigment development in Q. agrifolia leaves suggest that anthocyanins and xanthophyll cycle pigments serve complementary photoprotective roles during early leaf development. The results illustrate the use of reflectance indices for distinguishing divergent patterns of pigment activity in leaves of contrasting light history and functional type.     

根癌农杆菌介导转化红曲菌及转化子发酵性能的研究

利用根癌农杆菌介导转化技术成功将潮霉素抗性基因转入发白红曲菌中,优化了抗生素浓度,发白红曲菌孢子浓度,根癌农杆菌浓度,共培养温度及时间,以及乙酰丁香酮浓度等转化条件,最终转化效率可达52个转化子/105个红曲孢子.将转化子在含有潮霉素B的培养基继代培养5代,得到了多株稳定的转化子,对部分转化子进行PCR鉴定,结果进一步...     

降脂红曲的菌学性质及化学成分的分析

本文对No.4降脂红曲的生理特性进行了分析,测定了其一般的化学成分,将No.4红曲米的色调和色价与其它红曲米进行了对比,确定了该红曲的最适培养条件,制定了No.4红曲米的质量标准,并验证了它可作为糖化酶的生产菌。     

不产桔霉素的红曲霉菌种深层发酵生产莫纳可林K

对三株在YES培养基中不产桔霉素的红曲霉菌种,在摇瓶中研究了它们液体发酵生产莫纳可林K的情况。在大米粉培养基中,红色红曲霉不产莫纳可林K,但是紫色红曲霉和烟灰色红曲霉均能产莫纳可林K,前者产量高于后者。在葡萄糖．甘油培养基中,后两者的产量均很低,但是如果在该培养基中添加酵母膏,紫色红曲霉能产生较为可观的莫纳可林K。在2L的发酵罐中,利用添加了酵母膏的葡萄糖-甘油培养基,紫色红曲霉在第13d的莫纳可林K产量可达104mg/L,培养过程中无桔霉素产生。     

响应曲面法优化菌丝体中红曲色素的提取条件

以红曲菌丝体为原料,通过单因素实验及Box-Behnken设计响应曲面分析优化了红曲色素的提取工艺条件。通过实验,得到了提取率的回归方程Y=0.923-0.011X1-0.011X2-0.017X12-0.027X22-0.026X32-0.028X1X2-0.019X1X3,通过对模型解逆矩阵得优化方案:乙醇浓度X1=66%、超声功率X2=200 w、提取温度X3=52℃,模型预测结果为92.5%。在该工艺条件下进行验证实验,提取率达到92.1±0.6%(n=3)。     

洱海蓝藻爆发的时空特征及影响因子

湖泊生态环境对区域气候变化和流域人类活动十分敏感。随着流域的持续开发,洱海作为云贵高原第二大淡水湖泊面临着严重的生态与环境问题,主要包括水质恶化和生态功能的衰退,其中蓝藻水华问题尤为突出。针对湖泊现代监测数据存在时间序列较短、连续监测记录缺乏、监测位点不完全一致等问题,应用沉积物记录开展色素等多指标分析和环境变化重建研究,并对洱海湖区南、中、北3个湖盆的沉积物记录进行对比分析,从而探讨洱海富营养化与蓝藻爆发的历史与变化特征,并识别藻类响应模式的空间异同。沉积物色素记录结果表明,洱海蓝藻生物量变化具有明显的时空差异性,呈现由南至北,先后增加、最后呈现蓝藻水华全湖性持续爆发的模式。进一步的简约模型方差分解结果表明气候变暖和营养盐富集是洱海蓝藻生物量变化的主要驱动因子,此外相对较浅的南部湖盆还受到水位波动、水动力减弱、水生植物演化的综合影响。因此,在气候变暖的背景下,控制水体营养盐输入、合理调控湖泊水位、提高水体透明度并恢复水生植物是控制洱海蓝藻水华爆发和进行生态恢复的重要措施。     

Salicylic acid-induced adaptive response to copper stress in sunflower (Helianthus annuus L.)

The ameliorative effect of salicylic acid (SA: 0.5 mM) on sunflower (Helianthus annuus L.) under Cu stress (5 mg l⁻¹) was studied. Excess Cu reduced the fresh and dry weights of different organs (roots, stems and leaves) and photosynthetic pigments (chlorophyll a, b and carotenoids) in four-week-old plants. There was a considerable increase in Chl a/b ratio and lipid peroxidation in both the roots and leaves of plants under excess Cu. Soluble sugars and free amino acids in the roots also decreased under Cu stress. However, soluble sugars in the leaves, free amino acids in the stems and leaves, and proline content in all plant organs increased in response to Cu toxicity. Salicylic acid (SA) significantly reduced the Chl a/b ratio and the level of lipid peroxidation in Cu-stressed plants. Under excess Cu, a higher accumulation of soluble sugars, soluble proteins and free amino acids including proline occurred in plants treated with 0.5 mM SA. Exogenous application of SA appeared to induce an adaptive response to Cu toxicity including the accumulation of organic solutes leading to protective reactions to the photosynthetic pigments and a reduction in membrane damage in sunflower.