白藜芦醇制备方法及其生物活性的研究进展

白藜芦醇属蒽醌萜类化合物,是一种植物体内产生的天然二苯乙烯类活性多酚物质.本文通过查阅国内外相关文献,从提取方法、生理活性和生物合成3个方面对白藜芦醇制备技术进行了综述,以期为白藜芦醇的制备研究和开发利用提供参考.     

花生白藜芦醇研究进展

在花生体内,白藜芦醇合成酶是白藜芦醇生物合成途径中的关键酶之一,也是最主要的限速酶。将花生或葡萄中的白藜芦醇合成酶基因转化到其它植物中,可以有效提高植物的抗病性。本文简要介绍了白藜芦醇一般特性,对花生中白藜芦醇的分布、诱导因素作了相关介绍,并阐述了白藜芦醇在植物体内的生物合成途径及白藜芦醇合成酶基因的克隆、诱导表达及转化。     

Mitigative Effects of PFF-A Isolated from Ecklonia cava on Pigmentation in a Zebrafish Model and Melanogenesis in B16F10 Cells

Melanin synthesis is a defense mechanism that prevents skin damage, but excessive accumulation of melanin occurs in the skin in various reactions such as pigmentation, lentigines, and freckles. Although anti-melanogenic effects have been demonstrated for various naturally occurring marine products that inhibit and control tyrosinase activity, most studies have not been extended to in vivo applications. Phlorofucofuroeckol-A (PFF-A, 12.5–100 µM) isolated from Ecklonia cava has previously been shown to have tyrosinase-mitigative effects in B16F10 cells, but it has not been evaluated in an in vivo model, and its underlying mechanism for anti-melanogenic effects has not been studied. In the present study, we evaluated the safety and efficacy of PFF-A for anti-melanogenic effects in an in vivo model. We selected low doses of PFF-A (1.5–15 nM) and investigated their mitigative effects on pigmentation stimulated by α-MSH in vivo and their related-mechanism in an in vitro model. The findings suggest that low-dose PFF-A derived from E. cava suppresses pigmentation in vivo and melanogenesis in vitro. Therefore, this study presents the possibility that PFF-A could be utilized as a new anti-melanogenic agent in the cosmeceutical industries.     

茶树组织培养中的褐化控制研究

自20世纪60年代末以茶树幼茎小块为材料研究了离体咖啡碱的合成以来,茶树组织培养至今已走了约50年的研究历程,在多方面得到应用,但仍然有不少难题未攻克,主要有污染、褐化、玻璃苗、难以分化、再生体系不完善等等。其中,因为茶树多酚类物质含量高,褐化现象严重,阻碍了组培的后续工作。因此,有效的控制茶树外植体褐化是茶树组织培养的关键技术。本文就目前国内茶树组织培养的褐化控制研究进行综述,对茶树组织培养有参考意义。     

Tolerance to Fusarium wilt and anthracnose diseases and changes of antioxidative activity in mycorrhizal cyclamen

Mycorrhizal associations imply a remarkable reprogramming of functions in both plant and fungal symbionts. This consequent alteration on plant physiology has a clear impact on the plant responses to biotic stress management. As a consequence, a pot experiment was conducted to study the interactions between the arbuscular mycorrhizal fungus (AMF) Glomus fasciculatum and the two pathogens Fusarium oxysporum and Colletotrichum gloeosporioides and subsequent effect on growth, disease tolerance and the changes in antioxidative ability in cyclamen plants under growth chamber condition were investigated. At plant maturity, inoculation with F. oxysporum and C. gloeosporioides, responsible for Fusarium wilt and anthracnose of cyclamen respectively, significantly reduced shoot and root dry weights, increased both the disease incidence percentage and showed lower antioxidative activity viz. superoxide dismutase (SOD), ascorbate peroxidase (APX), ascorbic acid (AA) and polyphenol contents in plants. In contrast, the growth response and biomass production of cyclamen plants inoculated with AMF was significantly higher than the nonmycorrhizal control plants, both in the presence and absence of the pathogens. Mycorrhization enhanced plants to reduce the Fusarium wilt and anthracnose incidence compared to nonmycorrhizal controls. In every case, without and with pathogen association, plants inoculated with AMF increased the antioxidant (SOD, APX, AA and polyphenol) production compared to control plants. The results demonstrate that AMF have the ability to induce resistance against Fusarium wilt and anthracnose in cyclamen by increasing the antioxidative activity in plants, which promoted plant growth, biomass production and drastically reduced the disease incidence in cyclamen.     

茶多酚抗辐射研究进展

过量的辐射是多种疾病的主因,近年来摄入茶多酚被被认为有益健康,能够帮助人体抵御辐射。本文针对近年来茶多酚在体内和体外展开的实验,概括了茶多酚抗辐射的机理研究进展,新的研究理论表明茶多酚对人体健康有益,并阐释了茶多酚抗辐射的内在机理。     

茶树多酚氧化酶基因的克隆及其序列比较

根据已经发表的多酚氧化酶基因中的保守序列 ,设计兼并引物 ,利用nest-PCR技术 ,首次克隆了茶树多酚氧化酶基因。该基因已经在GenBank上登录 ,登录号为AF2 69192。序列分析表明 ,茶树多酚氧化酶基因与其它植物中的多酚氧化酶基因有较高的相似性 ,尤其在铜离子结合部位 ,所有的植物基本上一致。进化树分析表明 ,茶树的多酚氧化酶可以与大多数的木本植物聚合成一个组     

扦插时期、光照与密度等条件在马铃薯微型薯生产中的影响

在马铃薯微型薯生产过程中,扦插时期不同,使马铃薯植株不同物候期所处的环境条件不同,严重影响植株生物学性状及微型薯产量。试管苗扦插生根主要受温度影响,光照通过影响温、湿度对生根起作用。密度不同,植株生长受到影响,微型薯数量与产量均不同。     

Seaweeds and Their Natural Products for Preventing Cardiovascular Associated Dysfunction

Cardiovascular disease (CVD), which involves the onset and exacerbation of various conditions including dyslipidemia, activation of the renin–angiotensin system, vascular endothelial cell damage, and oxidative stress, is a leading cause of high mortality rates and accounts for one-third of deaths worldwide. Accordingly, as dietary changes in daily life are thought to greatly reduce the prevalence of CVD, numerous studies have been conducted to examine the potential use of foods and their bioactive components for preventing and treating CVD. In particular, seaweeds contain unique bioactive metabolites that are not found in terrestrial plants because of the harsh environment in which they survive, leading to in vitro and in vivo studies of their prevention and treatment effects. This review summarizes studies that focused on the beneficial effects of seaweeds and their natural products targeting markers involved in a cascade of mechanisms related to CVD pathogenesis. The purpose of this review is to describe the potential of seaweeds and their natural products for preventing and treating CVD based on in vivo and in vitro studies. This review provides a basis for future research in the field of marine drugs.     

稻田田埂植物的生物多样性

 在浙江安吉两个村对利用不同污染程度水源进行灌溉的稻田田埂植物进行了调查。利用未受工业污染的水灌溉的禹山坞稻田田埂植物种数高于受工业废水污染的城北村。在相同类型植物群落中, 禹山坞稻田田埂的植物种总重要值Iv(t)显著高于城北村,两村的田埂植物生物多样性指数也存在类似的变化趋势。不同类型植物群落的生物多样性参数差异极为显著, 矮秆植物占优势群落的植物种数、植物种总重要值和生物多样性指数(H')显著高于高秆植物占优势群落和外来植物占优势群落。应重视防除外来植物空心莲子草, 控制高秆植物和保护矮秆植物。     

Direct control of virus diseases

The prospects for the direct control of virus diseases are reviewed by examining relevant areas of current scientific research: (1) research aimed at elucidating the processes involved in the development of virus diseases; (2) research designed to improve our understanding of the natural defence mechanisms in plants. The development of a virus disease can be divided into three phases: (a) infection; (b) multiplication and spread; (c) symptom expression. First, large numbers of substances have been screened for effects on the processes of infection but so far without practicable results. The greatest effort has been devoted to studies of virus inhibitors already present in plants and other organisms. These are listed and their properties discussed. The effects of virus multiplication and on the host plant following treatment of infected plants with nucleic acid base analogues are described. The uracil analogues ribavirin and dioxohexahydrotriazine (DHT) have shown promising results. In extensive field trials, treatment of virus-infected potatoes with DHT significantly increased yield compared with untreated controls. Carbendazim has been used successfully to suppress virus-induced symptoms in tobacco, lettuce and rise. Secondly, plants possess a wide range of natural defence mechanisms, the nature of which is not understood. There has been considerable research into the question of how plants can localize some virus infections to a small number of cells around the point of infection. Research on the active agents possibly responsible is described, together with studies on the various chemicals that have been shown to activate or enhance this defence mechanism.     

Cryopreservation: an alternative for the long-term storage of old potato varieties

Summary A simple freezing method has been developed for the cryopreservation of an in vitro collection of old potato varieties. More than 125 varieties or genotypes have been frozen and stored in liquid nitrogen. Most varieties have high survival rates, averaging 80%. Plant regeneration rates were lower and averaged 40%. Plants have been obtained from all varieties or genotypes frozen and the phenotypes of regrown plants matched very well those of the unfrozen stock plants. However, one plant was found which was probably polyploid and five plants had poor growth. In addition, the genetic stability of 161 regrown plants was checked by flow cytometric measurements and DNA-fingerprinting. In the 161 tested samples neither polyploid plants nor unusual banding patterns were found.     

青蒿素对植物化感效应研究进展

青蒿素是一种由部分蒿属植物产生的倍半萜内酯,是一种有效的抗疟疾药物,对癌症、肝炎和血吸虫病等均有疗效。植物化感作用是植物(含微生物)通过释放化学物质到环境中对其它植物产生的直接或间接的有害作用。综述了青蒿素的合成、影响青蒿素化感效应的因素及释放途径、青蒿素对土壤成分及植物生长的影响等方面的研究成果,并指出了进一步的研究方向。     

转基因技术在大豆育种中的应用

获得转基因植株是植物基因工程的基础,但是由于转化效率较低,在转基因的过程中通常需要一个有效筛选细胞和组织的手段,于是选择标记基因被广泛应用.然而,选择标记基因的使用,存在生物安全性和环境安全性隐患.因此,建立一个安全高效稳定的大豆转化体系,是改善大豆产量、品质、抗逆能力,培育新型大豆品种的保障.该文综述了新型标记基因在...     

Die qualitätsbeurteilung von lebensmitteln mit hilfe des rattenversuches

For more than 50 years animal experiments have been used in nutrition and food research for the assessment of nutritional value and wholesomeness of foods. Due to economic as well as biological factors the rat is a suitable and most frequently used experimental animal. The composition of food can be determined with great precision by chemical analysis. For the assessment of the biological availability of the various nutrients one has to depend, with few exceptions, on biological tests, carried out predominatly on rats. Comparative investigations on man and rats have shown that the nutritional value of foods as obtained from rat studies can also be applied to man. For the detection of toxic substances and their effects on the mammalian organism animal experiments are still essential although several newer in vitro methods have been introduced. Three methods which are frequently used in animal experiments for determining the biological value of protein, the biological availability of food iron and that of food zinc are discussed in detail.     

饲料喂养方法评估草地贪夜蛾对玉米田多种植物的适应性

了解不同植物对植食性昆虫生物学特性的影响是昆虫-植物互作研究的基础,对制定有效的害虫防控策略具有重要意义。入侵害虫草地贪夜蛾（Spodoptera frugiperda）可能危害的植物多达353种,但大多数寄主植物对其生物学特性的影响尚不清楚。采集植物新鲜叶片饲喂植食性昆虫幼虫是研究的通用方法,而此方法受气候、地理位置、植物生长周期等条件的限制。以玉米（Zea mays）为参照,选取玉米农田及其周边的6种作物和杂草为试验材料,包括大豆（Glycine max）、豇豆（Vigna unguiculata）、番薯（Ipomoea batatas）、艾草（Artemisia argyi）、油麦菜（Lactuca sativa）和黄瓜（Cucumis sativus）。将上述植物的新鲜叶片统一采集、磨成粉末,按1%比例掺入人工饲料中,分别用这些饲料喂养草地贪夜蛾幼虫,观测其存活（幼虫存活率、化蛹率、羽化率）、生长（幼虫增重、蛹重、相对生长率）、发育历期（幼虫期、预蛹期、蛹期）和食物利用情况（相对消耗率、近似消化率、食物转化率、消化转化率）等,探究草地贪夜蛾取食这7种植物后的生物学特性。为验证植物叶片粉末饲料喂养方法的可行性,同时采集上述植物的新鲜叶片分别喂养草地贪夜蛾幼虫。结果显示大豆、豇豆是草地贪夜蛾适宜的寄主植物;而番薯、艾草、油麦菜对草地贪夜蛾的生长发育具有抑制作用,若将其运用于玉米间作系统中,可减轻草地贪夜蛾的为害。运用层次分析法建立指标评价体系进行量化评分,结果表明,植物粉末饲料和新鲜叶片喂养的效应一致,且前者限制条件少、操作简便,可较好地评估农田植物对草地贪夜蛾生物学特性的影响。     

The Role of Chitosan Oligosaccharide in Metabolic Syndrome: A Review of Possible Mechanisms

Metabolic syndrome, a cluster of metabolic disorders including central obesity, insulin resistance, hyperglycemia, dyslipidemia, and hypertension, has become a major public health problem worldwide. It is of great significance to develop natural products to prevent and treat metabolic syndrome. Chitosan oligosaccharide (COS) is an oligomer of chitosan prepared by the deacetylation of chitin, which is the second most abundant polymer in nature. In recent years, COS has received widespread attention due to its various biological activities. The present review will summarize the evidence from both in vitro and in vivo studies of the beneficial effects of COS on obesity, dyslipidemia, diabetes mellitus, hyperglycemia, and hypertension, and focus attention on possible mechanisms of the prevention and treatment of metabolic syndrome by COS.     

Vegetation management and biological control in agroecosystems

The application of diversity/stability considerations in theoretical ecology has led to the emergence of testable hypotheses with implications for biological control and agroecosystem management. The object of applied research in this area has been to achiece predictably stable pest populations (below an economic threshold level) in crop systems. The exacerbation of most insect-pest problems has been associated with increases in crop monocultures at the expense of the natural vegetation, thereby decreasing local habitat diversity. This can seriously affect the abundance and efficiency of natural enemies, which depend on habitat complexity for sources of alternate prey/hosts, pollen and nectar, shelter, nesting and overwintering sites. Plant diversification of agroecosystems can result in increased environmental opportunities for natural enemies and, consequently, improved biological pest control. Agronomically, there are several ways to design plsnt-diverse cropping systems. One way is by manipulating the vegetation of field margins, and managing the species composition and density of plants in ditchbanks, hedgerows, windbreaks and other types of shelter belts. Within-field plant diversity can be manipulated by designing polycultures of various temporal and spatial crop arrangements. The effects of some of these systems on the dynamics of insect populations are discussed, as well as the effects of cover-crop management on pest insects in orchards. Another way to enrich the vegetational structure of cropping systems is through weed management. Weed diversity in the form of weed borders, alternate rows, or by providing weeds in certain periods of the crop growth can have a major impact on insect dynamics.     

Crop losses caused by viruses

Several plant viruses are highly contagious and their effects on plants are often drastic. Many seriously reduce crop yield and quality. Numerous disorders are caused or triggered by viruses and a great deal of money is spent on preventing virus diseases from becoming disastrous. Losses caused by any disease cannot be measured directly because potential yield and damage are so variable. Experimental assessment of the losses attributable to virus diseases is particularly difficult because it is extremely hard to prevent contamination of healthy control plants and inoculation under vector-proof conditions may not reflect accurately what happens under natural conditions. The prevalence of the causal viruses or the extent of attack are not reliable guides to the amount of damage caused; this contrasts with the situation with invertebrate pests where losses are usually related to the population densities of the pests. In a few virus diseases, attempts have been made to establish the relationships between final yield loss and certain indicators such as incidence, severity and duration of disease, or between combinations of these, but the relationships seem to be valid only under strictly defined conditions. The main aims of this work have been to estimate actual losses inflicted on a farmer's crop or upon a larger area, to predict the magnitude of losses that may develop and to decide what control measures are justified. In practice, assessment of loss has been extrapolated from trials in which various infection severities and infection times have been used to simulate natural situations. Yield improvements with virus-free propagation material have sometimes been used for loss assessment. Losses caused by virus diseases depend on the cultivar involved: evaluation of the resistance of different cultivars may be further improved by assessing the effects of viruses on yield rather than by assessing the severity of symptoms. Losses is strictly financial terms are influenced by fluctuating prices for crop products and are even more difficult to asses, let alone to predict, than are losses of yield. Nevertheless, a better understanding of the way in which virus disease epidemics develop, and of the resulting biological and economic losses, is essential for effective crop protection, whether on individual farms or on a national scale.