四种稻瘟病生防菌的筛选及其活性评价

为了探明生防菌对稻瘟病菌的抑制作用,采用平板对峙法初筛、生长速率法复筛,从供试菌株中筛出4种对稻瘟病菌有明显抑制作用的目标生防菌,即解淀粉芽孢杆菌(Bacillus amyloliquefaciens)D1、嗜麦芽寡养假单胞菌(Stenotrophomonas maltophilia)he41、纺锤形赖氨酸芽孢杆菌(Lysinibacillus fusiformis)he14和枯草芽孢杆菌(Bacillus subtilis)H3。采用生长速率法测定4种生防菌无菌发酵滤液对稻瘟病菌的抑制作用,并对这4种目标生防菌活性的遗传稳定、耐高温、抗紫外线及耐酸碱的性质进行研究。结果表明,无菌发酵滤液的浓度在0.5%~64%时,对稻瘟病菌的抑制率为13.19%~100%之间。菌株D1、he41、he14、H3经转接培养30次,抑菌活性>86%,其发酵液经121 ℃高温处理后,菌株he14无菌发酵滤液的抑菌率达82%,而菌株D1、he41、H3发酵液经40 ℃处理后对稻瘟病菌则无抑制作用。菌株D1、he41、he14、H3在紫外灯(30 W)下照射6 h后,发酵液抑菌率仍达83%以上,经pH3~11的条件处理后,抑菌率>82%。综上,菌株he14是对稻瘟病具有一定生防作用的潜力菌株,为下一步开发防治稻瘟病的微生物制剂奠定了基础。     

超级设计师Pierre Paulin

不管怎样，难以阻止的是，Pierre Paulin经常激昂地说出，他被3位总统推举。第一个案例是他设计完成了爱丽舍宫的私人依据，在Francois Mitterand期间一套家具要代替属于CDG的LXV桌子。Jacques Chirac当任市长时，要求他重新设计里昂市政厅。     

为了老百姓 就是要叫真

有关食品质量的话题,可谓是老生常谈。它对于消费者而言,不但是关系到健康的问题,往大处说甚至是关系生命,因而任何一个存在于食品中的不安全因素都不是小问题。入世后欧盟、日本等地总是对我国的农产品出口关卡重重。这足以看出他们对于食品质量的重视。“打铁还要自身硬”,如果质量没有问题,人家也不会抓住小辫子不敢。但是如今,我们仍有很多企业的经营者还是不以为然,他们觉得产品不出口,只是在国内销售,出现个别的质量问题又不会引起国际纠纷,无须大惊小怪。然而,这样对企业来说是坏了名声、毁了牌子,而对于国家与整个食品行业来说,可谓是“一颗耗子屎毁了一锅汤”!     

An unidentified source of John Locke's some thoughts concerning education

An example of cultural exchange in the second half of the seventeenth century is discussed. The subject is a well-known case: John Locke's ideas on education, formulated during his five-year sojourn in Holland in the 1680s (autumn 1683 until spring 1689), a period during which as R. Colie stressed his whole life was to be changed neither he nor anybody else had any idea that he was the man whose ideas on human nature, on politics, on education were to cause such a change in English thinking in the course of the next century. According to Colie it was the intellectual climate of the Arminian (or Remonstrant) medical and theological circle in Amsterdam which stimulated the composition of his work, especially for a man as prepared as Locke, who could well carry out the conclusions he had reached in his head. In place of this interpretation the author shows that Lockes stay in Holland regarding educational questions of children was more than a period of compilation and composition of experiences made earlier, and of concepts prepared beforehand. It is suggested that Lockes ideas on education were far more influenced and much more stimulated by his encounters with Dutch educational literature (even to literal borrowing), on the one hand, and Dutch educational practice, mentality and culture, on the other, than has been credited by other researchers until now.     

Evolution of the genetic code in yeasts

During the last 30 years, a number of genetic code alterations have been uncovered in bacteria and in the mitochondria and cytoplasm of various eukaryotes, invalidating the hypothesis that the genetic code is universal and frozen. In the mitochondria of most yeasts, the UGA stop codon is decoded as tryptophan and the four leucine codons of the CUN family (N = any nucleotide) are decoded as threonine. Recently, a unique genetic code change involving the decoding of the leucine CUG codon as serine was discovered in the cytoplasm of Candida and Debaryomyces species, indicating that the genetic code of yeasts may be under specific evolutionary pressures whose molecular nature is not yet fully understood. This genetic code alteration is mediated by a novel serine-tRNA that acquired a leucine 5'-CAG-3' anticodon (ser-tRNACAG) through insertion of an adenosine in the intron of its gene. This event, which occurred 272 +/- 25 million years ago, reprogrammed the identity of approximately 30 000 CUG codons existent in the ancestor of these yeasts and had a profound impact on the evolution of the genus Candida and of other species. Here, we review the most recent results and concepts arising from the study of this genetic code change and highlight how its study is changing our views of the evolution of the genetic code.     

枇杷花系统溶剂提取物抑菌作用研究

研究枇杷花系统溶剂提取物抑菌的作用。实验以苯甲酸钠为对照组,分别研究了枇杷花石油醚、氯仿、乙酸乙酯、正丁醇、丙酮、95%乙醇和水的提取物对大肠杆菌、金黄色葡萄球菌、白色念珠菌的抑菌效果,并对不同提取物进行薄层色谱分析。结果表明,枇杷花的提取液对细菌、真菌均有抑制作用,并优于对照组。正丁醇、丙酮提取物对金黄色葡萄球菌抑制能力优于其他溶剂;石油醚提取物对大肠杆菌抑制能力优于其他溶剂;石油醚、乙酸乙酯提取物对白色念珠菌抑制能力优于其他溶剂。     

两性瓜尔胶接枝共聚物在蔗渣浆中的应用研究

对两性瓜尔胶接枝共聚物（LGG-g-PAM）在蔗渣漂白硫酸盐浆中的助留助撼性能进行了研究。实验表明：LGG-g-PAM7对浆料具有很好的助留和增强双重效果。LGG-g-PAM10显示出对沉淀碳酸钙（PCC）优越的助留效果。体系适宜DH范围是7～9,且该体系受高电导率的影响很小。细小纤维的首程留着率（FPR）随DDJ转速的增大而减小,但在转速小于1000r／min下助剂仍具有很好的助留效果。     

环境温度突变时人体热感觉变化机制研究进展

为完善人体热感觉评价体系,从环境温度突变特征参数、热感觉动态变化规律、热感觉预测模型3个方面对热感觉变化机制相关研究现状进行总结发现:环境温度突变的研究集中于中小温差突变,从热舒适的角度提出 5 ℃ 可能是不同环境温度突变的最大可接受温差阈值;动态热感觉与皮肤温度及其变化率、核心温度及其变化率有关;已有的热感觉模型预测精度较高,但在冷热环境温度突变下的适用性仍需大量人体实验进行优化与验证。最后指出有必要扩展环境温度突变研究的应用范围至特殊高温作业人群,建立突变强度分级规则,细化服装在温度突变下的作用,建立适用范围更广的热感觉预测模型。     

天然玫瑰茄红色素研究进展

天然食品色素是最近20多年来受到广泛关注一类食品添加剂,玫瑰茄红色素是从玫瑰茄花萼中提取花色苷类色素,是一种安全、无毒天然食用色素,具有抗氧化、保肝、降血脂、降血压等重要生物活性。目前,玫瑰茄红色素提取方法主要有:盐酸―乙醇提取法、微波辅助法、膜技术提取法等,并应用大孔吸附树脂纯化工艺进行精制。玫瑰茄红色素包括矢车菊素–3–葡萄糖苷、飞燕草素–3–葡萄糖苷、矢车菊素–3–接骨木二糖苷和飞燕草素–3–接骨木二糖苷四种花色苷,主要着色成分为后两者。我国已批准玫瑰茄红色素可作为食品添加剂使用[GB/T12493–1990(08.125)]。该文综述玫瑰茄红色素提取方法、纯化工艺、化学结构、理化性质和生物活性等,对该红色素综合开发具有一定参考价值。     

文山烟区烤烟气候适宜性评价及其变化特征分析

以文山各县区1991-2010年累计20年的气象观测数据为基础资料,基于模糊数学原理,运用多元统计分析方法对文山烤烟气候适宜性进行了综合评价,并采用线性趋势、三次多项式曲线拟合分析了烤烟生育期的各气候要素的变化特征。结果表明,文山烟区烤烟气候适宜性指数为0.801±0.018,各植烟县市均为最适宜或适宜烤烟气候区;文山20年中大田期日照时数变化总体呈上升趋势,呈现先下降后升高再下降的变化特征;伸根期均温总体呈下降趋势,而旺长期和成熟期均温总体呈上升趋势,各生育期均温呈现先短暂上升后下降再升高的变化特征;伸根期和旺长期降雨量总体呈上升趋势,而成熟期降雨量总体呈下降趋势,伸根期和旺长期降雨量呈现先下降后升高再下降的变化特征,而成熟期降雨量呈现先上升后下降的变化特征。     

我国已发布植物新食品原料公告分析及标准制定建议

目的初步构建我国植物新食品原料标准制定的思路和方法。方法通过研究2008—2017年以来原国家卫生和计划生育委员会发布的新食品原料(原新资源食品)公告中的植物新食品原料的各项要求,具体分析公告中规定的中文名称、拉丁名称、来源、食用部位、种植方式、使用范围、推荐食用量、不适宜人群、产品质量规格要求等内容,总结现行公告执行时出现的问题,并提出解决方案。结果现行植物新食品原料公告在实际应用时存在一系列问题,如公告格式和语言描述不统一、卫生安全指标定位不清、其他企业在使用公告时的适用性不强等问题。结论建议在技术审查环节不断完善我国植物新食品原料的公告内容,并构建植物新食品原料标准制定程序、方法和技术内容的框架,完善针对新食品原料的标准各项技术指标、标准审查制度等,建立我国植物新食品原料标准管理思路。     

怡良与两淮盐政改革

怡良于咸丰三年至七年（1853-1857）出任两江总督,兼理两淮盐政。在任期间针对国内形势,推行就场征课,并大力抵制以盐济饷活动。虽然在清代的两淮盐业史上,相较于陶澍、曾国藩、李鸿章等人大张旗鼓的改革,怡良显得较为默默无闻,但怡良的这些措施在客观上为曾国藩、李鸿章等人的后续改革做好了铺垫。     

微生物转化法制备人参皂苷Compound K 的研究进展

稀有人参皂苷Compound K(CK)是二醇型非天然人参皂苷,是其他二醇型人参皂苷在人体肠道内的降解产物。因其在抗肿瘤等方面有特效,需大量制备以满足医疗和科研需要,因此,有效获得稀有人参皂苷CK已开展了大量研究。本文就人参皂苷CK的微生物转化及制备进行系统的综述,旨在为其进一步开发利用提供参考。     

Dairy probiotics: Beyond the role of promoting gut and immune health

Today the importance of the so-called health-promoting bacteria or probiotics has been well established. Many of these probiotics are being delivered through fermented food products, of which dairy foods are among the most important carriers. The purpose of this report is to review some of the newer applications of probiotics that are situated far beyond the maintenance of gut health and which are currently being studied intensively on a laboratory scale, but have the potential to make it to the market in the future. We will discuss the current research status for applications in the fields of metabolic syndrome (obesity, diabetes, cardiovascular disease, etc.), psychotropic activity through the gut-brain axis, anti-mutagenic or anti-cancerous mechanisms and oral health. Finally, we will briefly review studies on a future generation of probiotics based on genetically modified strains that will deliver therapeutic molecules to the host.     

超声辅助提取黄栌色素及其性能

以黄栌枝干为原料,通过超声辅助提取黄栌色素。单因素实验结果表明:超声功率与提取率成线性关系;提取20min后可达平台期;乙醇体积分数、提取温度、料液比通过响应面法优化分别为68.03%、61.48℃、1.00∶18.83。在优化浸提条件下色素提取率为7.4%。进一步对色素进行了性能表征,结果显示:Na^+、K^+、Ca^2+、Mg^2+对色素稳定性的影响很小,Al3+使色素的最大吸收波长红移了6 nm,吸光度增大,Zn^2+、Fe3+和Cu^2+使色素沉淀产生不利影响;色素总还原力较Vc强;DPPH自由基清除能力较Vc弱,但在质量浓度达到0.18 mg/mL时,清除率仍可达92.3%。     

酪蛋白水解物的酶法修饰与ACE抑制活性变化

利用枯草杆菌碱性蛋白酶水解酪蛋白制备酪蛋白水解物,其水解度为11.2%,IC50为47.1μg/mL。再应用相同的酶对酪蛋白水解物进行类蛋白反应修饰,考察底物浓度、温度和酶添加量对类蛋白反应的影响,并制备5个不同的修饰产物测定其ACE抑制活性和IC50值。结果表明,修饰产物的ACE抑制活性随修饰程度(游离氨基减少量)的增加而提高,并且都高于未经修饰的酪蛋白水解物。当游离氨基减少量为154.65μmol/g(蛋白)时,修饰产物的IC50值可降至0.6μg/mL。毛细管电泳分析结果显示类蛋白修饰后水解物的多肽组成情况发生明显变化。研究结果证明酪蛋白水解物的ACE抑制活性可以通过类蛋白反应的修饰作用而提高。     

淀粉糊流变特性研究新进展

对淀粉糊和改性淀粉糊的流变特性研究分别进行了综述,详细介绍了各因素对淀粉糊的流变特性的影响以及不同物理化学改性方法对淀粉糊的流变特性的影响,指出今后应着重于淀粉糊流变特性各个影响因素的研究,获得各个因素对流变性能影响的规律,以开拓淀粉的广阔的应用前景。     

结肠定向吸收增强型递送体系的创建及应用研究进展

结肠定向吸收增强型递送体系是具有突出结肠靶向黏附能力和结肠增强吸收功能的新型结肠靶向递送体系.相较传统结肠靶向递送体系,其优势在于释放位点及作用时间的精准控制、递送体系比表面积的增加以及靶向黏附效果的增强.本文综述了结肠定向吸收增强型递送体系的研究进展和评价方法,并从结肠定向吸收增强型递送体系的类型、结构、制备方法及递...     

降低肉制品中氯化钠含量研究进展

从健康的观点来看,过度的摄入肉制品特别是传统的干腌肉制品不被推荐。因为这些肉制品钠含量较高,过度的摄入可能使人们导致高血压等心血管疾病。本文综述了氯化钠在肉产品加过过程中的作用、降低盐含量的方法以及他们对肉制品加工过程中品质的影响。为探索减低我国传统肉质品盐含量提供参考,有效提高肉制品的健康性。     

Altering pasting characteristics of sweet potato starches through amino acid additives

ABSTRACT:  This study assessed the effects of amino acid additives, aspartic acid, leucine, lysine, and methionine, on the pasting and thermal characteristics of white- and orange-fleshed Beauregard sweet potato starches. A rapid visco analyzer 3D was used to determine pasting properties. In comparing pasting characteristics, starch from orange-fleshed sweet potato was found to be easier to cook, had a lower potential for retrogradation, and was less stable during heating than the white-fleshed sweet potato starch. The RVA analysis showed that the charged amino acids, aspartic acid and lysine, altered pasting characteristics of the 2 starches more than the neutral amino acids, leucine and methionine. Aspartic acid had similar effects on both starches, making them less stable during cooking and lowering the potential for retrogradation. Lysine, when added to the orange-fleshed sweet potato starch, decreased the breakdown, allowing for more stability during cooking. This study showed that pasting properties of sweet potato starches can be altered by the addition of amino acids.