Natural and Modified (1→3)-β-D-Glucans in Health Promotion and Disease Alleviation

ABSTRACT

A number of polysaccharides with β -glycosidic linkage are widespread in nature in a variety of sources. All have a common structure and the (1→3)-β-D-glucan backbone is essential. They have attracted attention over the years because of their bioactive and medicinal properties. In many cases their functional role is a mystery, in others it is well established. Because of their insoluble chemical nature, particulate (1→3)-β-D-glucans are not suitable for many medical applications. Various methods of changing or modifying the β-D-glucan chemical structure and transforming it to a soluble form have been published. The β-D-glucan bioactive properties can be affected positively or negatively by such modifications. This review examines β-glucan sources in nature, health effects and structure-activity relationships. It presents the current state of β-D-glucan solubilization methods and discusses their effectiveness and application possibilities for the future.     

紫菀属植物化学成分及药理作用研究进展

紫菀属(Aster L.)植物为多年生草本、亚灌木或灌木,该属植物中紫菀(Aster tataricus)为常用中药,具有润肺下气、止咳祛痰之功效,主治气逆咳嗽、痰吐不利、肺虚久咳、痰中带血等症,是临床常用的润肺祛痰止咳药。该属所含化学成分较丰富,已对该属中16种植物做过化学成分研究,分离出的化合物124个,其类型有各种萜类及其苷、肽类、黄酮类、蒽醌类、甾醇类、香豆素、有机酸类及挥发油等。对国内外有关该属植物的化学成分、药理作用和临床应用的最新研究进行了综述,为该药用植物资源的进一步研究和开发利用提供依据。     

华南地区冬季开花植物及其园林应用

据调查,华南地区常用园林植物在冬季开花的有48科100余种(含部分品种和变种)。根据其生物学与生态学特性可划分为冬季开花、早春开花、四季开花、热带引种、人工育成新品种或促成栽培等五大类型。在园林上可作年宵花卉、行道树或景观树、地被植物以及切花等用途。     

施钾量和施钾时期对小麦氮素和钾素吸收利用的影响

利用¹⁵N示踪技术,研究了施钾量和施钾时期对高产小麦氮素和钾素吸收利用的影响.结果表明： 0～20 cm土层土壤速效钾含量为118.5 mg·kg^-1时,一次性基施钾肥未提高植株的氮、钾积累量;速效钾含量为79.0 mg·kg^-1时,施钾显著提高了植株的氮、钾积累量.采用分期施钾时（1/2基施、1/2拔节期追施）,随施钾量增加,小麦吸收的肥料氮和土壤氮量及追施氮肥在土壤中的残留量均增加,肥料氮的损失量降低.分期施钾显著提高了植株的氮、钾积累量、吸收效率和生产效率,当施钾量为135 kg·hm^-2时,与一次性施钾相比,分期施钾促进了植株对追肥氮和土壤氮的吸收,提高了追施氮肥在土壤中的残留量.结果还表明：施钾提高了小麦的籽粒产量、蛋白质含量和湿面筋含量;分期施钾处理优于一次性施钾处理,以K45+45（45 kg·hm^-2基施、45 kg·hm^-2拔节期追施）处理最优.过多施钾使小麦产量和品质趋于降低.     

A novel in vitro flat‐bed perfusion biofilm model for determining the potential antimicrobial efficacy of topical wound treatments

Aims: To develop an in vitro flat‐bed perfusion biofilm model that could be used to determine the antimicrobial efficacy of topically applied treatments. Methods and Results: Pseudomonas aeruginosa and Staphylococcus aureus biofilms were grown within continuously perfused cellulose matrices. Enumeration of the biofilm density and eluate was performed at various sampling times, enabling determination of the biofilm growth rate. Two antimicrobial wound dressings were applied to the surface of mature biofilms and periodically sampled. To enable real‐time imaging of biofilm growth and potential antimicrobial kinetics, a bioluminescent Ps. aeruginosa biofilm was monitored using low‐light photometry. Target species produced reproducible steady‐state biofilms at a density of c. 10⁷ per biofilm support matrix, after 24‐h perfusion. Test dressings elicited significant antimicrobial effects, producing differing kill kinetic profiles. There was a good correlation between photon and viable count data. Conclusions: The model enables determination of the antimicrobial profile of topically applied treatments against target species biofilms, accurately differentiating bactericidal from bacteriostatic effects. Moreover, these effects could be monitored in real time using bioluminescence. Significance and Impact of the Study: This is the first in vitro biofilm model which can assess the antimicrobial potential of topical therapies in a dynamic growth environment.     

蜜蜂抗菌肽研究及其应用进展

抗菌肽是一类由特定基因编码的小分子多肽,广泛分布于各种生物中,是生物天然免疫的重要效应分子,其对缺乏获得性免疫系统的昆虫尤为重要。蜜蜂是一种对环境极其重要的社会性模式昆虫,又有着极高的经济价值,因此蜜蜂抗菌肽有着较大的研究意义。本文对蜜蜂4种天然免疫抗菌肽(Apidaecin、Abaecin、Hymenoptaecin和Defensin)和蜂产品中的抗菌肽(Jelleines、Melittin和Apamin)研究进展进行了综述,介绍了它们的功能、作用机制及其应用,提出了蜜蜂抗菌肽未来可行的研究方向,旨在推动蜜蜂抗菌肽的研究。     

膜分离技术及其在生物农药生产中的应用

膜分离技术与传统分离技术相比,具有明显的优势,常用于现代生物制药中分离、浓缩、分级与纯化蛋白质、多肽等热敏性生物药品.该文重点讨论微滤(MF)、超滤(UF)、纳滤(NF)等膜分离技术在生物农药生产中的应用.     

基因工程在工业中的应用

基因工程技术的不断进步,为经济的发展注入了新鲜的血液;其应用涉及经济发展的诸多领域。本文仅简要介绍其在医药工业、酶制剂工业、环保工业、食品工业以及化学与能源工业上的应用情况。     

细胞融合技术的发展及应用

细胞工程是四大生物工程之一,细胞融合技术作为细胞工程的一项核心基础技术已在农业、医药、环保等领域取得了开创性的研究成果,而且应用领域不断扩大。细胞融合技术的不断改进一方面表现在融合剂上,另一方面体现在新方法上,再者体现在融合对象的不断扩展上。现在新的细胞融合方法正在尝试将各种物理、化学手段综合应用,使细胞融合的方法和手段向操作更为简便,便于量化研究,同时又能使融合率得到不断提高的方向发展。本文以细胞融合技术的发展历史为主线,对上述内容做了简要综述。     

Phosphorus Transformations under Reduction in Long-term Manured Soils

The widespread recycling of animal wastes as fertilizers can severely affect the phosphorus cycle, especially in soils that undergo periodical flooding and anaerobiosis. The aim of this study was to investigate the effect that reducing conditions have on the release and forms of P in soils that have received different doses (0, 60 and 120 Mg/ha) of liquid hog manure for 15 years. Samples of the topsoil (0–20 cm) and of subsoil (20–40 cm) were placed under static reducing condition. At the onset of the reduction, P release to the solution reached a maximum after 4 weeks of submersion then levelled off, presumably due to readsorption by the soil matrix. When an anionic resin was added to act as a P-sink the amount of P released nearly doubled for most samples. The soils that had received the highest dose of manure released more P than the others. Draining the soil solution at intervals after reduction removed up to 683 μg P/kg of the soil with the highest manure dose. The forms of P measured after the experiments revealed a shift of the resilient forms towards more labile, bioavailable forms thus increasing the potential for P loss. ^†Deceased