花生资源及抗性鉴定对抗黄曲霉研究的基础作用

1992和1995年发表的花生资源对黄曲霉菌抗性鉴定的论文,奠定了1996年秋起开展的花生抗黄曲霉菌侵染的抗病育种工作和1999年起开展的花生对黄曲霉菌侵染的遗传分析与抗性机理研究的基础.通过275份花生资源对黄曲霉菌侵染的抗性鉴定,筛选出的梅县红衣、湛秋48、新会小粒、UF71513-1、VRR245、PI337394F、AH7223等7个抗性品种和粤油92、汕油523两个感病品种成了抗病育种的抗原亲本或引种鉴定的对照品种或遗传分析和抗性机理研究的供试品种.在抗性鉴定中采用的材料与方法,包括黄曲霉菌株As3.2890、察氏琼脂培养基、供试花生仁表面消毒方法、感染率的分级标准等常被用于花生引种鉴定、遗传分析与抗性机理研究,这充分表明资源及抗性鉴定对花生抗黄曲霉研究奠定了坚实的基础.     

花生荚壳抗黄曲霉菌侵染的鉴定方法研究及抗性种质发掘

        黄曲霉毒素污染是影响花生食用安全性和制约产业发展的重要因素。荚壳是花生抵御黄曲霉菌侵染的第一道防线,为建立花生荚壳抗黄曲霉侵染的鉴定方法,本研究利用强侵染黄曲霉菌AF2202接种花生荚果,通过对不同接种菌浓度和培养时间的比较分析,发现接种浓度为2 ×106孢子/mL、培养7d的组合方案可以有效区分花生荚壳对黄曲霉菌侵染的抗性。利用所建立的鉴定方法对276份遗传变异丰富的花生核心种质材料进行接种鉴定,进一步证明了这一方法鉴定花生荚壳抗性的有效性和实用性,初步发掘出2份具有荚壳抗性的特异花生种质。     

102份不同来源花生种质对北方根结线虫抗性的田间鉴定

为选育抗线虫花生品种,在北方花生根结线虫分布较均匀的自然病田中种植了102份花生种质,收获时对其进行抗性鉴定调查,得到高感材料14份、中感材料76份、中抗材料12份、耐病材料1份,未发现免疫和高抗种质材料;调查发现种间杂种的杂交后代抗性较强,中抗材料较多;自然病田田间观察发现,紫色种皮花生种质的抗性表现较好。     

花生种质资源对黄曲霉菌侵染的反应

对来自我国不同生态区的700份花生种质进行抗黄曲霉菌侵染的评价。鉴定结果表明,700份花生种质中,大部分对黄曲霉菌侵染表现高感,低侵染率（50％以下）种质仅12份,其中EF7284的侵染率最低,为28．57％。低侵染率花生种质均来自南方生态区的珍珠豆型材料,本文对低侵染率花生种质的主要植物学,农艺性状及品质性状作了分析评价。     

花生种质资源对黄曲霉菌侵染和产毒的抗性鉴定

对不同种子成分的花生种质资源对黄曲霉菌侵染和产毒的抗性进行了鉴定,结果表明,高含油量、高蛋白质含量和高油酸含量资源对黄曲霉菌侵染和产毒的抗性较差.通过对抗黄曲霉侵染和产毒能力不同的花生种质资源的种子成分的分析表明,高抗黄曲霉菌侵染和产毒资源的亚油酸含量较高.相关分析表明,不同花生品种对黄曲霉菌的侵染抗性与种子大小和油酸含量呈显著负相关,与出仁率和亚油酸含量呈显著正相关;不同花生品种对黄曲霉菌产毒的抗性与含油量呈显著负相关.通过鉴定和筛选,发掘出2份优质抗病资源.     

花生抗黄曲霉毒素污染研究进展

从三个方面简要介绍了开展花生抗黄曲霉毒素污染的研究进展。在抗侵染方面，鉴定了１５７６ 份花生种质，大多数种质样本的黄曲霉菌侵染率在５０％ 以上，只有２ 个种质的３ 年平均侵染率在１５％ 以下。方法学研究方面，提出了ＴＦ法和改良ＴＦ法。这两个方法都适合于大量鉴定花生种质的抗产毒性， 能快速筛选出抗性种质。在抗产毒性鉴定方面，鉴定了１５１７份花生种质，大多数种质不具有抗性， ８４４％ 的接种样本中的产毒量在３１μｇ／ｇ 以上，而种质Ｎ１２１１ 和Ｎ１３２２ 的允许产毒量连续４ 年在１２μｇ／ｇ 以下。     

花生抗青枯病种质对黄曲霉菌产毒的抗性反应

通过人工接种和毒素测定,对抗、感青枯病的花生种质进行了黄曲霉菌产毒抗性评价.结果表明:1)抗青枯病花生种质之间存在着黄曲霉产毒抗性的显著差异,品种间毒素含量高低相差近10倍,鉴定出抗黄曲霉产毒种质6个;2)2种抗病性无相关性;3)获得具有直接生产利用价值的兼抗青枯病和抗黄曲霉产毒的花生材料1个.     

花生国外引种抗锈病鉴定

本文是对３６份于１９９１年引自国际半干旱热带作物研究所（ＩＣＲＩＳＡＴ）的国外花生种质资源材料经１９９２年春植和１９９３年春植田间自然诱发抗锈病鉴定结果。其中高抗类型１９份，占５２．８％，中抗类型１５份，占４１．７％；中感类型２份，占５．５％。试验结果表明，这批引进的花生种质资源材料抗锈性较强，２年鉴定的抗锈性表现稳定。     

花生不同贮藏时间对黄曲霉菌侵染和产毒的影响

通过对在常温条件下分别贮藏1～4年的10个抗黄曲霉菌产毒的花生材料进行人工接种鉴定研究,初步探讨了花生种子贮藏时间对黄曲霉菌侵染和产毒的影响.结果表明,通过多年连续选择的抗产毒花生种质材料在人工接种条件下黄曲霉毒素含量普遍低于高产毒对照品种.随着种子贮藏时间的增加,黄曲霉菌对花生的侵染和产生分生孢子所需的时间缩短.贮藏2～4年花生种子的产毒量显著高于贮藏不足1年的种子,而且贮藏环境的湿度对种子活性和黄曲霉产毒量有很大影响.不同抗性种质在耐贮能力和抗性的持久性方面存在明显差异.     

玉米种质资源对大斑病的抗性鉴定

“八五”期间在昆明、成都、丹东等地对我国2538份玉米种质资源进行了大斑病抗性鉴定的结果；高抗材料2份，抗病材料12份，中抗材料127份，感病2397份。     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

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.     

Redox Status and Neuro Inflammation Indexes in Cerebellum and Motor Cortex of Wistar Rats Supplemented with Natural Sources of Omega-3 Fatty Acids and Astaxanthin: Fish Oil,Krill Oil,and Algal Biomass

Health authorities worldwide have consistently recommended the regular consumption of marine fishes and seafood to preserve memory, sustain cognitive functions, and prevent neurodegenerative processes in humans. Shrimp, crabs, lobster, and salmon are of particular interest in the human diet due to their substantial provision of omega-3 fatty acids (n-3/PUFAs) and the antioxidant carotenoid astaxanthin (ASTA). However, the optimal ratio between these nutraceuticals in natural sources is apparently the key factor for maximum protection against most neuro-motor disorders. Therefore, we aimed here to investigate the effects of a long-term supplementation with (n-3)/PUFAs-rich fish oil, ASTA-rich algal biomass, the combination of them, or krill oil (a natural combination of both nutrients) on baseline redox balance and neuro-inflammation indexes in cerebellum and motor cortex of Wistar rats. Significant changes in redox metabolism were only observed upon ASTA supplementation, which reinforce its antioxidant properties with a putative mitochondrial-centered action in rat brain. Krill oil imposed mild astrocyte activation in motor cortex of Wistar rats, although no redox or inflammatory index was concomitantly altered. In summary, there is no experimental evidence that krill oil, fish oil, oralgal biomass (minor variation), drastically change the baseline oxidative conditions or the neuro-inflammatory scenario in neuromotor-associated rat brain regions.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

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.     

<Emphasis Type="Italic">Pulque</Emphasis>, An Alcoholic Drink from Rural Mexico,Contains Phytase. Its <Emphasis Type="Italic">in vitro</Emphasis> Effects on Corn Tortilla

Pulque is made by fermenting the agave sap or aguamiel of Agave atrovirens with a whole array of microorganisms present in the environment including several lactic acid bacteria and yeasts such as Saccharomyces cerevisiae. Ascorbic acid was determined in pulque and aguamiel, respectively. Phytase activity in lees, liquid and freeze-dried pulque was assayed by measuring the appearance of phosphate from phytate by a colorimetric method likewise phosphate from phytate present in fresh corn tortilla was measured after in vitro incubation with pulque. Iron, zinc, calcium, magnesium and selenium contents were measured in pulque and corn tortilla as well as in nixtamalized corn flour (NCF), the latter is used to make instant tortilla, since corn provides most of the energy as well as most of the phytate in the Mexican rural diet. Pulque showed phytase activity but much less ascorbic acid and iron than previously reported; additionally, phytase in pulque hydrolyzed most of phytate’s corn tortilla. Lees, which is mostly made of pulque’s microbiota, significantly accumulated iron and zinc but no selenium. NCF was fortified with iron by the manufacturers but poorly blended. There were significant differences on selenium content between tortillas samples, apparently some soils in central Mexico are selenium deficient. Moderate pulque intake appears to increase the bioavailability of iron and zinc bound by phytate in corn.