黑荆树树皮原花色素生物活性的研究

对黑荆树树皮中原花色素的提取及生物活性进行了研究.实验分别以水、甲醇和乙醇作为提取溶剂,对黑荆树皮中原花色素的提取进行了探讨,通过测定其总抽出物含量和原花色素粗提物得率的影响,确定了适宜的提取条件,并重点对原花色素生理活性包括抗肿瘤和抗氧化活性进行了评价.利用MTT比色法对原花色素抗肿瘤活性进行了测定,利用清除DPPH自由基能力测定了其抗氧化能力.实验结果表明,黑荆树树皮是一种富含原花色素的植物资源.提取溶剂选择性试验结果表明,乙醇作为提取溶剂,不仅可以得到较高提取率的原花色素,而且所得原花色素粗提物具有较高的生理活性.黑荆树树皮原花色素适宜提取工艺条件为:溶剂浓度 70%,提取温度 60 ℃,液料比7∶1.体外癌细胞培养的抑制作用测试结果显示,黑荆树树皮提取得到的原花色素粗产品对人早幼粒白血病细胞HL-60有中效,分别对人低分化胃腺癌细胞BGC-823和人肝癌细胞BEL-7402有弱效.自由基清除能力测定结果显示黑荆树树皮中原花色素提取物有很强的抗氧化活性.     

黑荆树皮原花色素的提取及美白防晒效果试验

原花色素是一种具有生物活性的类黄酮类化合物,因具有良好的生理和药理效用,在保健品、化妆品以及医药领域有很大的应用潜力。本研究以由传统栲胶原料黑荆树皮提取分离得到的原花色素为有效成分制备美白防晒霜,探讨其美白防晒效果。结果表明,黑荆树皮原花色素对酪氨酸酶抑制作用的IC50值为0.44 g/L,揭示黑荆树皮原花色素具有抑制黑色素生成而达到美白的作用。其抑制酪氨酸酶的酶动力学结果显示,原花色素对酪氨酸酶的抑制作用属于竞争性抑制。此外,UVB区(280~320 nm)紫外吸收和小鼠抗紫外线试验表明,添加3%(质量分数)黑荆树皮原花色素的美白防晒霜具有中等防护紫外线照射的防晒效果,可用于中等强度阳光照射的防辐射保护,达到市售防晒产品效果。因此,传统林化产品黑荆树皮原花色素可以作为美白防晒霜的有效成分,有助于拓展林源性活性物质的应用领域。     

利用剩余污泥制备生物絮凝剂的实验研究

污水处理厂剩余污泥原泥及沼渣中的微生物含有蛋白质等大分子物质,其在生长过程中产生的蛋白质、多糖等代谢物质具有一定的絮凝能力,可作为生物絮凝剂使用。污泥中微生物的一些胞内物质也具有一定的絮凝活性。为探索使用剩余污泥和沼渣制备生物絮凝剂的实验条件,采用酸法和碱法对剩余污泥原泥和沼渣进行了破解处理制备生物絮凝剂。结果表明：碱法破解原泥和沼渣效果明显优于酸法破解原泥和沼渣。当原泥和沼渣的碱解液碱度较高时,继续向碱解液中投加适量原泥或沼渣,仍可得到可观的COD释放量,且可降低原泥和沼渣的碱解液碱度。经过碱解处理后,剩余泥饼的有机质含量均显著降低。     

植物谷胱甘肽代谢与镉耐性研究进展

谷胱甘肽是植物体内一类重要的抗氧化物质。本文综述了植物硫素同化、谷胱甘肽生物合成与代谢的主要生物学过程,镉(Cd)胁迫显著影响植物体内的硫素同化和谷胱甘肽合成,表现出"低促高抑"的效应。植物通过硫代谢来合成半胱氨酸(Cys),再经由2种关键酶催化合成谷胱甘肽。Cd胁迫促进还原型谷胱甘肽转化为氧化型谷胱甘肽,激活ASA-GSH循环,清除活性氧自由基,维持细胞内的稳态。谷胱甘肽转化生成植物螯合肽(PCs),能有效络合细胞内游离态的Cd离子,转运到液泡中进行区室化储存。因此,谷胱甘肽及其代谢产物在植物对Cd的吸收转运、累积与解毒中,发挥着重要的作用。最终,硫代谢、谷胱甘肽生物合成、不同类型谷胱甘肽联系在一起,在抗氧化和降解重金属毒性等方面发挥协同作用,从而增强植物对Cd胁迫的耐性。Cd胁迫下植物谷胱甘肽代谢与植物抗性相关的机理研究仍不明确,谷胱甘肽代谢与其相关的代谢产物之间具有怎样复杂的相互作用和信号传导,这是今后亟待强化和解决的。     

木质素生物降解与生物制浆的研究现状分析

综述了木质素生物降解与生物制浆的研究现状 ,包括木质素降解代谢产物和降解途径与机制的研究、参与木质素降解的酶及其作用机制的研究、木腐菌对木材和木质素降解能力的研究以及高效降解木质素的生物制浆用优异菌株的筛选。对木质素生物降解与生物制浆的研究进行了展望。结果表明 :生物制浆由于既节省能源又有环境友好的特性而具有毋庸置疑的应用前景 ,在我国加强木质素生物降解和生物制浆的研究是势在必行的 ,这对于保护环境 ,缓解能源危机以及制浆造纸业的可持续发展都具有重要的意义。     

有机磷农药微生物降解的研究进展

指出了有机磷农药在我国的使用量很大,不但污染环境,还经过食物链将有毒物质富集在生物体内,进一步危害人类。微生物降解技术是一种降解效率高、代谢方式多、耗费成本底、反应条件比较温和、无二次污染的技术,是降解有机磷农药的重要方法,这种技术能够很大程度的降低有机磷农药对环境和人类产生的危害。综述了有机磷降解菌的降解措施、菌的筛选分离、分类鉴定和种类以及降解机理的进展,为有机磷农药的微生物降解技术的使用研究提供参考。     

白腐菌预处理在生物质材料中的应用

白腐菌经长期的生物进化,形成了一套独特的生理生化机制和强大的降解代谢能力,在木质和非木质材料预处理中都有广泛的应用。介绍了白腐菌特点及其降解木质素机理,对近年来国内外白腐菌预处理在生物质材料改性中的应用进行综述,重点论述了白腐菌预处理在改善渗透性、提高产氢量、生物制浆、糖化和醇解、堆肥以及饲料预发酵等方面的研究进展,并提出未来白腐菌在生物质材料领域应用的研发重点,为生物质材料的合理利用提供参考。     

弧形竹材胶合成型工艺研究进展

竹类植物种类繁多,资源丰富,应用广泛。在竹材加工利用中,不破坏或少破坏竹材原有的生物力学性能、天然外观颜色及纹理极其重要。弧形原态重组竹材是在此原则下开发生产的竹质产品,具有重要推广价值。从竹材特性出发,阐述了竹材成板过程中面临的问题,进而指出弧形原态重组竹开发的必要性,论述了弧形原态重组竹的生产过程、力学性能、破坏机理及其应用,以期为弧形原态重组竹材规模化生产提供理论依据。     

毛杨梅、余甘子、落叶松树皮原花色素抗氧化能力研究

从毛杨梅、余甘子、落叶松3种树皮中提取分离得到原花色素产物.通过测定3种树皮原花色素产物的清除DPPH自由基能力、三价铁还原抗氧化能力(FRAP)和抑制油脂过氧化能力,综合评价了3种树皮原花色素的抗氧化活性.结果表明,3种树皮原花色素均显示出良好的抗氧化能力,其抗氧化活性强弱顺序为:毛杨梅树皮原花色素＞余甘子树皮原花色...     

原花色素的制备工艺

原花色素是具有很强作用的抗氧化剂和自由基清除剂，能预防和治疗因自由基引发的各种疾病。因此，原花色素己成为医药、保健品的重要原料及食品、化妆品的重要添加剂。 原花色素提取物的精制过程主要是除去水溶性杂质，研究表明这种杂质主要是糖类（包括多糖、寡糖及小分子糠类）及少量粗蛋白（包括多肽、寡肽）等。 这些杂质不溶于丙酮，而原花色素提取物的水溶液中加入一定量的丙酮，可使上述这些杂质沉淀而被除去，从而达到精制的目的。用这种方法，不仅原花色素的收率高、操作简单易行，而且成本低、产品质量有保证。 原花色素的制备工…     

Effect of growing site,sampling date,wood location in trunk and drying method on concentration of soluble proanthocyanidins in Betula pendula wood,with special reference to wood colour

Proanthocyanidins (PAs), which are common phenolic compounds in plants, are considered to be mainly defensive compounds against different kinds of stress, e.g. herbivory. In addition to increasing after stress, they may condense and/or oxidize to form coloured compounds when cells die, which may affect both the resistance of xylem to rot and its colour. This is important in the mechanical wood industry. The effects of some biological factors (growing site, sampling date, wood location in the trunk) on the concentration of soluble PAs (sPAs) were studied in fresh and dried birch wood. Those factors that affected sPA concentration most were sampling date and radial location. Drying method also had a great effect on the sPA concentration, which in turn correlated with the colour of the wood.     

An institutional analysis of deforestation processes in protected areas: The case of the transboundary Mt. Elgon,Uganda and Kenya

Protected areas (PAs) are a country's key strategy to conserve and manage forest resources. In sub-Saharan Africa, the effectiveness and efficiency of PA institutions in delivering sustainable outcomes is debated, however, and deforestation has not been avoided within such formal regimes. This paper analyzes the processes that led to deforestation within the PAs on the transboundary Mt. Elgon, Uganda–Kenya, employing institutional theory. Landsat satellite imagery helped identify and quantify forest loss over time. The study showed how, since 1973, about a third of all forests within the PAs on Elgon have been cleared in successive processes. Within formal protected area regimes, complex political and institutional factors drive forest loss. We argue, therefore, that policies to counter deforestation using a PA model have to be considered and understood against the broader background of these factors, originating both inside and outside the PA regimes.     

Effectiveness of Protected Area Governance in the Conservation of Mt. Marsabit Forest Ecosystem,Kenya

ABSTRACT

Protected area systems (PAs) have the potential to conserve natural resources and provide social and economic benefits to local communities. Establishing and maintaining good governance and associated mechanisms is necessary for adaptive management of PAs. To test this hypothesis, we analyzed the relationships between various stakeholders and the effectiveness of PA governance of Mt. Marsabit forest ecosystem in Kenya. We used social network analysis (SNA) to assess the interactions between actors, and factor analysis to analyze the effectiveness of governance criteria. Governance of Mt. Marsabit forest ecosystem was complex with a multiplicity of stakeholders from diverse interests. Governance was moderately effective (61%) with positive indicators including the regulatory framework, delineation of areas under conservation, and reduction in poaching. The low level of interactions and associations among stakeholders suggest a weakness in the networks that may negatively affect the flow of information and other resources. This weakness was attributed to a lack of institutionalization of the links leading to poor coordination of processes. Local communities were inadequately represented in the governance of this PA despite being important actors. Our study finds that local ownership and strong linkages between actors are important ingredients for effective governance of PAs.     

Characterization of proanthocyanidins from grape seeds

Leucoselect (grape seed selected proanthocyanidins) was analyzed. HPLC thermospray mass spectrometry (TSP-MS) allowed the detection of monomeric flavan-3-ols and dimeric proanthocyanidins. Fractionation over Sephadex LH-20 resin and analysis of the isolated fractions by gel permeation chromatography (GPC) and electrospray mass spectrometry (ESI-MS) led to the complete characterization of the proanthocyanidin constituents of Leucoselect. The analysis revealed the presence of approximately 15% of (+)-catechin (1) and (-)-epicatechin (2), 80% of (-)-epicatechin 3-O-gallate (3), dimers, trimers, tetramers and their gallates and 5% of pentamers, hexamers, heptamers and their gallates.     

5α-Reductase inhibitory compounds produced by polymerization of resveratrol with horseradish peroxidase

To produce 5-reductase inhibitory compounds, resveratrol was enzymatically oxidized in a horseradish peroxidase (HRP)/H₂O₂ system. Ethyl acetate extract of the oxidation products showed strong 5-reductase inhibitory activity with 10%–15% organic solvents in the system, whereas without organic solvent little inhibitory activity was exhibited. The optimum pH of enzymatic oxidation for acquisition of the inhibitory activity was 4.5. The inhibitory compounds were isolated and identified as resveratroltrans-dehydrodimer and resveratrolcis-dehydrodimer by comparing with published nuclear magnetic resonance data. The two resveratrol dehydrodimers have stronger inhibitory activity than natural resveratrol dimers and trimers found inShorea species.     

多胺在植物抗逆中的生理机制

多胺（PAs）是一类低分子量、聚阳离子、脂肪族含氮物质,是植物对逆境响应的重要物质。国内外众多研究表明,在逆境胁迫下,植物体内不同类型的PAs,例如腐胺（Put）、亚精胺（Spd）、精胺（Spm）的含量会发生变化,外源PAs会对植物的抗逆性产生不同的影响。但多胺的研究对象多集中在农作物,对木本植物的研究较少。PAs对植物抗逆的作用机制较为复杂,不同种类的多胺对植物的抗逆影响不同,PAs的代谢与参与逆境胁迫的其他代谢密切相关。文中主要综述PAs在植物抗干旱、低氧、高温、低温、盐、重金属过程中的变化及生理作用机制,以期为开展PAs与抗逆林木研究、栽培与抗逆育种研究提供参考。     

Unbiased evaluation of bioactive secondary metabolites in complex matrices

The majority of bioactive principles in a complex matrix such as natural products and botanical medicines are secondary rather than primary metabolites. In addition to being chemically diverse, the bioactivity of an ethnobotanical can comprise from one to several bioactive compounds, present in a complex mixture. Conventional discovery efforts utilize bioassay-guided fractionation (BGF) to isolate individual active compounds. When applied to complex natural products, BGF is often challenged by an apparent loss of activity during fractionation, resulting in weakly active isolated compounds. Metabolomic analysis can potentially complement existing the BGF paradigm by capturing the chemical complexity of the metabolites. The proposed biochemometric approach establishes a link between the chemistry of a secondary metabolome and a deserved health impact, using a high-throughput, high-resolution capable biological endpoint. The proof of principle is demonstrated for the anti-tuberculosis (TB) activity of the Alaskan ethnobotanical, Oplopanax horridus. Biochemometric analysis identified the 100 most active constituents from thousands of metabolites in the active extract by means of 2D orthogonal chromatography using countercurrent and GC-MS methods. Previously isolated O. horridus phytoconstituents were used as reference markers of known structure and bio (in)activity. Positive correlations allowed distinction of anti-TB actives from inactive compounds. A total of 29 bioactives from 3 main structural classes were assigned based on MS data. Biochemometric analysis is a new tool for the standardization of herbal medicines and ethnobotanicals, as well as for drug discovery from nature. The method can assign multiple active compounds in complex mixtures without their prior isolation or structure elucidation, while still providing an interface to structural information.     

红树林真菌的生物多样性和生物工程应用潜力(英文)

本文对现今红树林真菌研究的热点领域进行了综述,包括红树林真菌的生物多样性,生态作用,新颖的代谢产物和生物工程应用前景四个方面。首先,红树林真菌按照其生态作用被分为腐生,寄生和内生真菌。其中腐生真菌对于红树林生态系统的降解和能量循环方面起着重要的作用,另外,它们也会产生一些毒素:寄生真菌对于红树林的存活,长势和健康程度起着重要的作用;而内生真菌分布于大部分红树之中,所产的活性物质是红树林真菌中最丰富的。其次,虽然已有大量文献报道了红树林真菌可以产生很多新酶和具有’抑菌,杀虫及其它活性的物质,并且很多由内生真菌产生的活性物质被认为对红树起着重要作用,但只有少量研究对此提供了有力的证据,因此,本文对现今应用分子技术来将红树林真菌的生态作用与其代谢产物联系起来的进展进行了讨论。最后,本文还讨论了利用代谢工程和后基因组技术来生产大量新酶和活性物质并将其商业化应用的前景。     

Can Biodiversity Conservation Benefit Local People? Costs and Benefits at a Strict Protected Area in Uganda

This article examines the livelihoods and experiences of local people after two decades of living close to a strict protected area (PA). A total of 290 local PA neighbors and 60 key informants were interviewed. Findings reveal a limited access to assets and low incomes. An average PA neighbor earns US$0.5 per adult equivalent unit (AEU)/day. PA proximity is associated with lower incomes, mainly because of wildlife damages that cost an average household (HH) up to 10% of its annual income. Other recurrent PA costs include the “invisible” costs incurred to cope with crop raiding, and restricted access to PA resources, that jointly amount to 16% of an average HH’s annual income. PA benefits include the sharing of tourism revenues, integrated conservation and development projects, and park-related employment. In total, benefits constitute 3.5% of the total annual income of an average HH, a figure higher than the contribution of other PAs in Uganda. However, overall, an average HH accrues a net annual loss of 12.5% of its total income or a total loss of US$1.54 million for the 1,1875 HHs, yet the park sends up to US$7 million to the central treasury. This highlights the need for policy revisions of the political economy of PA management.