茶叶中β-葡糖甙酶活性的测定

β-葡糖甙酶(EC3,2,1,21 β-D-葡糖苷葡糖水解酶)存在于自然界许多植物体,特别是植物的果实中。最初,人们在甜杏仁中发现此酶,便称之为“杏仁酶”,迄今,杏仁仍是获取β-葡糖甙酶的主要原料。β-葡糖甙酶还存在于一些酵母、曲霉菌、木霉菌属以及细菌体内。β-葡槽甙酶的特性是可水解结合于末端、非还原性的β-D-糖苷键,同时释放β-D-葡萄糖和相应的配基。现有的研究结果表明,茶叶中的一类重要香气化合物——单萜烯醇类便是在β-葡糖甙酶的作用下,由其配糖体水解而得以释放出来的。根据酶来源的不同,不同生物体中β-葡糖甙酶水解单萜烯醇配糖体时,对单萜烯醇的结构有所选择,例如,茶叶中的β-葡糖甙酶既可水解伯醇(如香叶醇),又可水解叔醇<如芳樟醇),但有些植物体中的β-葡糖甙酶仅能水解伯醇或叔醇。     

车前草多糖的结构和性质初探

从车前草中提取、分离纯化得到多糖组分PPII-a,并对其组成结构和性质进行分析。车前草经热水提取、DEAE-Sepharose F.F柱层析、Superdex-200柱层析得到车前草多糖PPII-a,经HPLC、UV、IR、比色、β-消去等方法对其组成结构及理化性质进行测定。结果表明:PPII-a为均一组分,相对分子质量为4.6×105Da,其总糖含量、蛋白含量、糖醛酸含量分别为90.5%、9.7%、20.9%,单糖组成及摩尔比为阿拉伯糖∶甘露糖∶葡萄糖∶半乳糖=7.6∶1∶1.8∶1.9;呈现多糖特征吸收峰,含有β-吡喃糖苷键。β-消去实验结果表明,糖链与结合蛋白之间是通过O-型糖肽键相连。因此,PPII-a是一种均一的具有O-糖肽键的酸性杂多糖。     

普洱茶的抗氧化酚类化学成分的研究

从云南省双江县勐库产的普洱茶中分离得到11个化合物,分别为:(-)-没食子儿茶素(GC,1),(-)-表儿茶素(EC,2),(+)-儿茶素(C,3),杨梅素(4),没食子酸(5),山奈酚(6),山奈酚-3-O-β-D-葡萄糖甙(7),山奈酚-3-O–芦丁糖甙(8),槲皮素(9),槲皮素-3-O-β-D葡萄糖甙(10)以及2,5-二羟基苯甲酸(11)。其中,化合物6~11为首次从普洱茶中分离得到。DPPH自由基清除活性测试结果表明,化合物2、3、5的活性与阳性对照品抗坏血酸接近。化合物的结构与其活性的关系比较分析表明,简单儿茶素(2,3)和简单酚类化合物(5)的抗氧化活性较高,与阳性对照品抗坏血酸接近;黄酮类化合物(4,6,9)次之,黄酮类配糖体(7,8,10)及化合物11则较差。     

普洱茶E8组分的化学成分研究

采用HPLC制备色谱等分析了普洱茶乙酸乙酯提取物E8组分的化学成分,并通过LC/MS和NMR等对制备得到的化合物进行了结构鉴定。结果表明,从E8组分中分离鉴定出5个化合物,分别为3',4',5-三羟基-7-甲氧基黄酮、3',4',5,7-四羟基黄酮（木犀草素）、槲皮素-3-O-β-D-葡萄糖甙、3',4',7-三羟基-5-甲氧基黄酮-7-O-β-D-葡萄糖甙和3',4',7-三羟基-5-甲氧基黄酮。     

菠萝皮果胶的分离纯化及组成分析

以热带水果菠萝皮为原料,采用漂烫灭酶、酸法提取和醇沉工艺提取果胶,对提取果胶的分离纯化和组成进行研究.结果表明:菠萝皮果胶经离子交换层析后分离纯化出1个中性组分,命名为PRP-N,2个酸性组分,命名为PRP-1、PRP-2.比对PRP-1、PRP-2的组成和结构发现,PRP-1的半乳糖醛酸含量较低,中性糖含量较高,单糖成分主要为鼠李糖、半乳糖和阿拉伯糖,以鼠李糖半乳糖醛酸Ⅰ型(RG-Ⅰ)结构为主,侧链主要成分为阿拉伯糖和半乳糖,通过4-O-Rha连接到主链上;PRP-2的半乳糖醛酸含量高,中性糖含量低,以半乳糖醛酸型(HG)和鼠李糖半乳糖醛酸Ⅱ型(RG-Ⅱ)结构为主,含有少量RG-Ⅰ型果胶分子结构.PRP-1比PRP-2的流体力学体积小,且聚合度分布更集中.     

Kionochaeta中2个中国新记录种和2个大陆新记录种

对采自贵州省习水国家自然保护区（长嵌沟管理站）和贵州省燕子岩国家森林公园若干份枯枝进行室内的标本保湿处理,对其上的暗色丝孢菌采用形态学鉴定法。根据Kionochaeta（悬刺毛孢属）的典型特征：由菌丝体分枝产生分生孢子梗。分生孢子梗粗大、单生、直立、直或稍弯曲、光滑、具隔、厚壁、褐色至黑褐色、锥形、刚毛状,无或伴生侧生刚毛状分枝的分生孢子梗。可育区域通常在分生孢子梗的中下部,极少在顶端;由紧凑或松弛,不规则或流苏状排列,其上产生产孢细胞。产孢细胞安瓿形,烧瓶形或圆柱形,具2种增殖类型：（1）内壁芽生式,没有持续导致平周变厚;（2）内壁芽生式,持续的及顶式产生新的产孢位点。分生孢子内壁芽生式,顶生,单生,产生一个液滴（在基质上）,透明,无隔膜,光滑,椭圆形、梭形、镰状或棒状,极少在两端具一个简单的刚毛。HMZNC0426菌株的典型特征：较长刚毛状分生孢子梗在整个生长过程中缺乏紧密、分枝的产孢结构,但顶端可能产生一系列短的不规则分枝的产孢细胞,刚毛状分生孢子梗基部常伴生一种顶端具产孢结构,较短的分生孢子梗;HMZNC0356菌株的典型特征：分生孢子梗无侧生刚毛状分枝,产胞结构产生在分生孢子梗近中部单一位点上,产孢细胞紧密、无规则排列在分生孢子梗中部;HMZNC0381菌株的典型特征：分生孢子梗中下部着生2~5根侧生的刚毛状分枝,主轴和侧枝的部分顶端着生一系列不规则、短的分枝,其上产生产孢细胞,从而形成可育区域;可育区域位于侧枝下端,构成紧密、分枝、透明至浅褐色的产孢细胞;HMZNC0427菌株的典型特征：分生孢子梗中部着生一根侧生的刚毛状分枝,较短,可育区域位于侧枝下端。根据上述特征鉴定出：Kionochaeta内的K. nanophora Kuthub. & Nawawi (HMZNC0426)和K. spissa P. M. Kirk & B. Sutton (HMZNC0356)为中国新记录种,K. australiensis Goh & K. D. Hyde (HMZNC0427)和K. pughii Kuthub. & Nawawi (HMZNC0381)为中国大陆新记录种。该标本保存在遵义师范学院真菌学标本室（HMZNC）。     

凝胶与溶胶的结构分析

本研究采用先进的傅立叶转换红外光谱及力学——振动光谱手段,并运用电子计算机,研究生胶的凝胶与溶胶的结构及力学性能,由于样品制备严格,并且系统地去除胶样中的非胶组分,所以获得比前人更准确、更深入的结果。本研究结果表明,凝胶与溶胶中的蛋白质的组成与含量有所不同,橡胶烃分子结构亦有差异,主要是分子链上功能基团数目不同。因此,在凝胶中橡胶烃分子与蛋白质分子的基团间形成氢键,橡胶分子通过氢键交联成网状结构。采用3种新颖方法计算的凝胶分子链上功能基团数目的结果基本一致。因此,从理论上来说,本研究具有较大的意义。     

小麦茎基腐病抗性QTL的分析

为挖掘更多的茎基腐病抗性QTL用于分子标记辅助育种,以中抗茎基腐病品种CI12633和感茎基腐病品种扬麦158的重组自交系群体为材料,采用SSR和SNP等分子标记对群体中的94个家系进行基因型分析,绘制遗传连锁图,并结合3次室内群体的茎基腐病抗性鉴定结果对小麦茎基腐病抗性QTL进行定位。结果表明,与小麦茎基腐病抗性相关的QTL分布在1D、2B、3B(2)、7A和7D染色体上,可解释9.2%～14.6%的表型变异;1D和3B染色体上的抗性QTL来自CI12633,2B、7A和7D染色体上的抗性QTL来自扬麦158;1D、2B和3B(与Chr3B_479785994紧密连锁)染色体上的抗性QTL为茎基腐病抗性主效QTL。发现的QTL及其紧密连锁的分子标记可为今后开展抗茎基腐病小麦分子标记辅助育种提供帮助。     

辣木叶黄酮苷的分离鉴定及抗氧化活性研究

为研究辣木（Moringa Obleifera Lam.）叶片中的黄酮苷成分及其抗氧化活性,利用MCI凝胶柱、羟丙基葡聚糖凝胶（Sephadex LH-20）柱层析、硅胶柱层析（CC）、半制备高效液相色谱等分离手段对石油醚组分进行分离和纯化,利用LC-MS、1H-NMR、13C-NMR等现代波谱技术对分离得到的化合物进行结构鉴定,采用SRB法和DPPH·清除率对分离得到的化合物进行体外抗肿瘤活性筛选和抗氧化活性的测定。结果表明,从辣木叶的石油醚部分分离得到4个化合物,已鉴定为β-谷甾醇（Ⅰ）、胡萝卜苷（Ⅱ）、槲皮素-3-O-β-D-葡萄糖苷（Ⅲ）、山柰酚-3-O-β-D-葡萄糖苷（Ⅳ）。4种化合物均具有抗氧化活性,但化合物Ⅲ的抗氧化活性极显著强于其他三种化合物;体外抗肿瘤活性表明,化合物Ⅰ和化合物Ⅱ对乳腺癌细胞株（MDA-MB-231）有一定的抑制作用。      

灰茶尺蠖雌成虫生殖器形态特征与组织结构的研究

为了解茶树主要食叶类害虫灰茶尺蠖(EctropisgrisescensWarren)雌成虫的内外生殖器结构特征,通过解剖切片和显微观察的方法,明确了雌成虫内外生殖器主要由1对卵巢、1对侧输卵管、1根中输卵管、1个受精囊、附腺、产卵孔、交配囊及其附属结构、导精管、表皮突和肛突等组成。卵巢小管8根,左右对称;交配囊呈典型袋状结构,内有表面布满刺状突的心型交尾囊片,且囊片左右两侧16根刺状突呈对称分布;后表皮突较细长,似铲状。切片观察可知,卵巢管滋养细胞和卵母细胞交替排列,为典型的多滋式;产卵器内有发达的性腺等。掌握灰茶尺蠖雌成虫生殖器结构,对其卵巢发育级别划分、田间预测预报、近缘种的鉴定以及性信息素的研究等具有重要意义。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.