遮荫对木薯块根淀粉含量和品质的影响

以2个木薯主栽品种(SC124、SC8)为材料,自盛暑期开始遮荫(植后70 d至植后160 d),对植后160 d木薯块根进行淀粉含量及相关酶活性分析,结合扫描电镜观察遮荫处理与正常光照下木薯块根淀粉结构的变化,探讨弱光对木薯贮藏淀粉含量和品质的影响。结果表明,遮荫处理改变了木薯光合产物在"源"与"库"之间的分配,造成茎叶变长,茎干细弱,块根减重,根冠比显著降低。弱光显著影响淀粉含量及其组成,遮荫处理提高或显著提高了SC124和SC8块根直链淀粉含量,降低了2个品种块根的总淀粉含量和支链淀粉含量,以及支链淀粉与直支链淀粉的比率。遮荫处理后木薯块根AGPase活性均降低;GBSS活性增加(SC8)或无显著变化(SC124);而遮荫处理对SSS和SBE活性影响不一致。扫描电镜观察表明,遮荫处理形成许多直径较小的淀粉粒,影响淀粉充实程度而造成淀粉含量降低。     

高压诱变小麦突变体籽粒淀粉积累的动态变化

为了解高压诱变小麦突变体籽粒灌浆过程中的淀粉积累特性,以未经高压处理的偃展4110纯系为对照,对经过高压诱变处理(120MPa,8h)获得的偃展4110突变株系高压2、高压3、高压5、高压9和高压11的籽粒形成过程中淀粉含量的动态变化进行了分析。结果表明,突变株系籽粒总淀粉、直链淀粉、支链淀粉含量均呈"S"型曲线变化;总淀粉、直链淀粉、支链淀粉积累速率表现为"抛物线"型曲线变化,花后15~20d为籽粒总淀粉、直链淀粉、支链淀粉含量增加最快的时期;高压2、高压5的总淀粉、直链淀粉、支链淀粉含量高于对照,高压9低于对照;成熟期高压2和高压9的总淀粉含量分别为80.99%和73.05%,与对照(77.38%)差异显著(P0.05),说明高压诱变对淀粉积累有影响。不同样品之间总淀粉、直链淀粉、支链淀粉含量变化速率存在显著差异(P0.05),对照的总淀粉、支链淀粉峰值速率高于其他突变株系;高压2和高压5的直链淀粉峰值速率明显高于对照。     

小麦直、支链淀粉和总淀粉含量的比色快速测定研究

为了快速准确地测定小麦直、支链淀粉含量,通过单波长法、双波长法、多波长法对比色法测定小麦直、支链淀粉含量进行了比较,并对影响测定结果的试验条件进行了优化和分析.结果表明,与马铃薯相比,小麦面粉直、支链淀粉-碘复合物吸收曲线存在一定的差异.用单波长法、双波长法、多波长法测定小麦直、支链淀粉含量,均能得到相关性很高的回归方程.双波长和多波长法可以有效地排除其他物质的干扰,测定结果优于单波长法.多波长法测定复杂,结果计算繁琐,因此双波长法更适用于小麦直、支链淀粉含量的同时测定,其测定结果也优于多波长法.在双波长法中,小麦直链淀粉的适宜测定波长为630和486nm,小麦支链淀粉的适宜测定波长为550和743nm.溶液酸碱度pH值3.5左右.     

木薯种质资源淀粉特性分析与评价

为了评价和筛选出淀粉品质优良的木薯资源,对212份国内外栽培木薯种质块根淀粉产量性状及淀粉含量、直链淀粉含量、支链淀粉含量、粘度峰值和糊化温度5个重要淀粉特性指标进行研究。结果表明,不同木薯资源各淀粉特性差异较大,不同指标间有一定的相关性,利用概率分级法将8个淀粉产量及特性性状分为5级,即极低、低、中、高和极高,推荐极高品系可作为木薯淀粉品质育种利用的基础亲本材料,其中直链淀粉含量极高资源共17份;支链淀粉含量极高资源共18份。利用主成分分析得出前2个主成分反映木薯参试资源块根淀粉特性的83.79%信息,第1主成分主要包括淀粉率、直链淀粉含量和支链淀粉含量,隶属函数法综合评价得出,‘SM2300-1’等12份木薯资源淀粉综合特性最好,更适合木薯淀粉的深加工与利用。     

青稞籽粒淀粉含量的差异

为筛选特色淀粉青稞材料,采用双波长法测定和分析了来自西藏、青海、甘肃、四川、国外的栽培青稞以及野生裸大麦共469个青稞材料的直链和支链淀粉含量。结果表明,这些青稞材料的直链淀粉含量平均为24.65%,变异范围为4.09%（昆仑8号）~39.72%（长芒红四棱）,其中西藏材料最高（26.87%）,甘肃材料最低（21.23%）;支链淀粉含量平均为31.76%,变异范围为15.24%（康青1号）~60.09%（喜玛拉雅2号）,其中野生裸大麦最高（35.51%）,西藏材料最低（30.17%）;总淀粉含量平均为56.00%,变异范围为31.28%（阿青5号）~74.41%（阿里当地青稞）,以野生裸大麦最高（58.11%）,青海材料最低（54.19%）。根据淀粉含量分布特征将不同来源青稞材料间直、支链及总淀粉含量都分成4个级别,这些青稞材料的直链淀粉含量主要分布在第3级,支链和总淀粉含量主要分布在第2级。从中筛选出18份具有特殊淀粉含量的青稞材料,可用于专用青稞的培育。     

木薯分支酶活性测定及同工酶电泳技术应用初探

淀粉分支酶(Starch branching enzyme,SBE)是唯一引入α-1,6糖苷键分支点,催化支链淀粉形成的酶,影响淀粉分支程度及淀粉粒的精细结构。本文以3个亲缘关系较远的高产木薯品种(SC124、SC8、Arg7)为材料,利用SBE同工酶电泳及酶活性检测观察木薯块根支链淀粉增长较快时期SBE活性变化动态,结合支链淀粉含量检测分析木薯淀粉同工酶表达特点与支链淀粉积累的关系。结果表明:种植后140d至180d为木薯单株支链淀粉含量快速增加时期;SC124和SC8支链淀粉积累量早于Arg7达到高峰;Arg7各个时期的支链淀粉含量及SBE活性均表现最高。同工酶分析表明,木薯分支酶有SBE-I和SBE-II两个基因位点:SBE-Ι至少有3个等位基因位点(SBE-Ιa、SBE-Ιb、SBE-Ιc),品种间具有多态性;SBE-II为单一条带,但活性大小在品种间和发育不同阶段有差异。初步判定等位基因位点SBE-Ιc和SBE-II可能对SBE酶活性和支链淀粉含量贡献较大。     

木薯采后生理性变质与淀粉特性研究

以华南系列的SC205、SC5、SC6、SC8和SC10五个木薯品种为材料,于采收后不同时间分析其块根生理变质程度、干物质含量、淀粉含量、支链淀粉比例和淀粉透明度等指标,探讨木薯生理变质与块根淀粉特性的关系。研究结果表明：采后生理变质对块根淀粉特性有明显影响,所有品种淀粉特性指标在采后均呈下降趋势,其中下降最快的是SC205。对各指标的相关分析表明,支链淀粉分别与淀粉含量和淀粉透明度呈显著正相关和极显著正相关。可见,生理变质可导致淀粉透明度的下降,影响淀粉的商品品质。     

不同生长期木薯块根淀粉糊化特性的差异

对木薯品种(系)SC8、南植199、C869、D346和E632在6～11个月生长期的块根淀粉糊化特性进行研究。结果表明,木薯的含粉量随生长期的延长呈先增后减趋势,不同品种的变化拐点各不相同;直链淀粉含量随生长期变化趋势因品种而异,表现出显著的品种效应和生长期差异性;峰值粘度在生长期为8个月后随生长期的延长而增加,其值与鲜薯含粉率、直链淀粉含量呈显著正相关关系;木薯淀粉糊化温度的生长期差异性显著,且变化趋势因品种的差异而略有不同,它与直链淀粉含量呈显著负相关关系。木薯淀粉恩氏粘度与直链淀粉含量呈显著正相关。     

灌浆前期高温对小黑麦籽粒淀粉积累及其合成相关酶活性的影响

为探讨灌浆前期高温对六倍体小黑麦籽粒淀粉积累及其相关合成酶活性的影响,以4个春性小黑麦品种（系）为材料,在开花后5~14 d于田间搭建温棚进行高温胁迫,对其籽粒淀粉积累动态、淀粉合成相关酶活性进行了研究。结果表明,开花后5~14 d高温胁迫导致小黑麦千粒重和容重均显著下降,其中,千粒重下降5.95%~20.47%,容重下降3.33%~9.49%;籽粒中的总淀粉、支链淀粉与直链淀粉含量均显著降低,依次下降6.84%~17.97%、7.70%~24.60%及2.27%~7.17%,直/支链淀粉比有所升高,但差异不显著。在高温胁迫期间,小黑麦籽粒中与淀粉合成相关的腺苷二磷酸葡萄糖焦磷酸化酶（AGPP）、可溶性淀粉合成酶（SSS）、淀粉分支酶（SBE）及淀粉去分支酶（DBE）活性均较对照有所上升,高温胁迫结束后,AGPP、SSS、DBE的活性均较对照有所下降。推测灌浆前期高温胁迫导致灌浆中后期小黑麦籽粒中淀粉合成相关酶活性的下降是籽粒中淀粉含量降低以及千粒重、容重下降的主要原因。     

调控木薯淀粉合成的干涉载体构建及转化木薯的研究

为了调控木薯块根淀粉含量与组成,以甘薯块根特异表达Sporamin A启动子驱动构建了腺苷二磷酸葡萄糖焦磷酸化酶AGPase小亚基(ADP-glucose pyrophosphorylase small subunit 1,AGPase SU1)、可溶性淀粉合成酶(soluble starch synthase 1,SSS1)、颗粒性淀粉合成酶(granule-bound starch synthase 1,GBSS1)的干涉载体,通过农杆菌介导法转化木薯SC205的胚性愈伤,获得了转化再生株系。酶切鉴定及测序表明,构建的上述3个调控木薯块根淀粉合成的干涉载体构建正确,对获得的转化再生株系用潮霉素筛选及潮霉素抗性基因HPT的引物进行扩增,部分株系有阳性扩增条带,初步说明本研究获得了以调控木薯块根淀粉含量与组成的转基因木薯SC205株系。     

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.     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.     

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.