Identification of three triterpenoids in almond hulls

Three triterpenoids, betulinic acid, oleanolic acid, and ursolic acid, were isolated as their methyl esters (treatment with diazomethane) from diethyl ether extracts of almond hulls (Nonpareil variety) using flash chromatography and preparative high-performance liquid chromatography. The triterpenoids, which comprised approximately 1% of the hulls, were characterized using chromatographic and spectroscopic methods. These studies demonstrate that almond hulls are a rich source of these triterpenoids, which have reported anti-inflammatory, anti-HIV, and anti-cancer activities.     

Fast and efficient discrimination of the Isotoma viridis group (Insecta: Collembola) by PCR-RFLP

Identification of collembolan species is generally based on specific morphological characters, such as chaetotaxy and pigmentation pattern. However, some specimens do not match to described characters because these refer to adult specimens, often of one specific sex, or the characters are highly variable in adults (e.g. pigmentation, setae or furcal teeth). Isozymes have frequently assisted species discrimination, and also these may vary with developmental stage or environmental conditions. For identification of single species of the Isotoma viridis group, we present both direct sequencing of the cytochrome oxidase subunit II (COII) gene and a simple DNA-based molecular method.

Five PCR primers amplifying the COII region (717 bp) of the mitochondrial DNA were used. The sequences clearly separated the species I. viridis, I. riparia and I. anglicana, irrespective of colour varieties within the first species. DNA amplification products of different species can also be distinguished by digestion with restriction endonucleases, followed by gel electrophoresis for separation of fragments. This restriction fragment length polymorphism (RFLP), obtained after digestion with the endonucleases TaqI, VspI, MvaI and Bsp143I, revealed specific fragments that separated the three species from each other. Since restriction enzymes are sensitive to single base mutations, we suggest to use a combination of enzymes with at least two species-specific restriction sites when using the RFLP technique. For the I. viridis complex, VspI and Bsp143I appear to be an appropriate combination.     

气候变化对中国南方水稻生产的阶段性影响及适应性对策

根据GISSGCMTransientBRun的输出结果 ,结合中国南方稻区 15个样点近 4 0年的逐日气候资料 ,生成了每个样点在 2 0 10年、2 0 30年和 2 0 5 0年的气候变化情景 ;利用CERES Rice模型在基准气候 (196 0～ 1997年 )以及上述不同年份的气候变化情景下运行的结果 ,结合中国若干农业气候指标 ,分区评述了未来 10年、30年和 5 0年全球气候变化对不同稻作类型水稻生育期、产量、稻田蒸散量的阶段性影响 ,并分析了中国稻作制度可能发生的演进趋势。最后 ,在模拟试验的基础上 ,提出了若干适应气候变化的农业对策 ,包括调整品种布局、有条件地扩种双季稻、改善灌溉条件及培育和引进新品种等。该研究结果对国家及各级农业行政部门制定中远期农业规划和农业发展战略具有重要的参考价值     

猕猴桃果浆贮藏期间维生素C和叶绿素的变化

讨论了猕猴桃果浆的 3种不同贮藏方法 ,发现 0～ 2℃冷藏 12 d后绿色几乎全失 ,Vc减少约2 5 .6 % ;脱气 0～ 2℃冷藏 18d后绿色几乎全失 ,Vc减少约 5 .6 % ;- 18℃冷冻贮藏 18d叶绿素减少约 2 3.7% ,Vc减少约 11.4% ,18d后叶绿素、Vc含量趋于稳定 ,贮藏 5个月时 ,叶绿素减少约 36 .3% ,Vc减少约 14.9%。结果认为 - 18℃冷冻贮藏是猕猴桃果浆一种较好的贮藏方法     

软枣猕猴桃原生质体培养与细胞团再生的初步研究

以软猕猴桃叶片、叶片愈伤组织为材料，研究了影响原生质体分离和培养的因素。结果表明，原生质体分离，酶液配方2优于配方1，成龄叶片优于幼龄叶片；培养方法以浅层培养法最好；改良MS液体培养基培养愈伤组织原生质体，5-7d出现第一次细胞分裂，14d出现第2次细胞分裂，30d形成多细胞团，55d形成肉眼可见的小愈伤组织。     

板材三维尺寸自动检测装置的研究

该装置分为三路对板材的长、宽、厚三个尺寸进行自动检测。长度检测选用光电码盘传感器。宽度检测选用激光扫描器,它产生自左至右的扫描平行光线。板材通过检测台。遮住部分光线,未被遮住的部分光线由受光器接收。并经过光电转换器把光信号转换为电信号。厚度检测采用旋转变压器。由于板材厚度的改变。旋转变压器的旋转角度发生变化,从而使旋转变压器的输出电势不同。长、宽、厚三路检测信号经接口电路送往单板机。接着程序先进行长度检测。而后宽、厚同时检测。该装置检测精度高。     

夏橙生长期果实套袋对采后贮藏品质的影响

以奥林达夏橙为试材,研究了生长期套袋和未套袋果实在采后贮藏期间主要品质指标的变化规律。结果袁明：套袋果和未套袋果的失重率均呈上升趋势,未套袋果的上升幅度比套袋果大;可滴定酸和维生素C具有相同的下降趋势,但未套袋果的下降幅度比套袋果大;未套袋果的可溶性固形物和可溶性总糖趋于下降,但变化幅度较平缓,而套袋果的可溶性固形物和可溶性总糖的变化幅度较大,在贮藏后期,可溶性固形物下降,可溶性总糖上升。     

Effects of Supplemental Histamine on Gastric Acid Secretion, Digestive Enzyme Activities, Intestinal Microfloral of Early Weaned Piglets

Two experiments were conducted to study the effect of supplemental histamine in the diet ofearly-weaned piglets. In experiment A, 24 cross bred piglets with an average body weight of 6.10±0.40 kg,weaned at the age of 28 days, were divided into four groups, fed with basal diet of low dietary copper without(control) or with supplemental histamine at 60, 120, 180 μg kg-1 BW. During the two weeks and the thirdweek after weaning, ADG(average daily gain) of piglets were increased by 15.8% (P＜0.05), 9.5% (P＜0.10) by addition of 60 μg kg-1BW histamine, but decreased by addition of 180 μg kg-1BW histamine, whichalso increased the amount of E. coli in colon and the scour incidence. The secretion of gastric acid and pepsinwere improved by both dose of supplemental histamine (60, 180 pg kg-1BW) and gastric digesta pH were de-creased by both. Addition of 60 μg kg-1 BW histamine improved the activities of trypsin, amylase in duodelumdigesta. In experiment B, 12 cross bred piglets with an average body weight of 6.85±0.35 kg, weaned at theage of 28 days, were divided into two groups, fed with basal diet of high dietary copper without (control) orwith supplemental 60 μg kg-1 BW histamine. During the two weeks and the third week after weaning, ADG ofpiglets were increased by 9.8% (P＜0.05), 7.0% (P＜0.10). The secretion of gastric acid, activities oftrypsin and amylase in duodelum digesta, were also improved by addition of 60 μg kg-1 BW histamine. The re-sults showed that addition of histamine (60 μg kg-1 BW) in early weaned piglets could increase the secretion ofgastric acid and pepsin, reduce gastric digesta pH and scour incidence, improve activities of trypsin, amylasein duodelum digesta, and the growing performance of early weaned piglets.     

Food choice and reproductive success of Folsomia candida feeding on copper-contaminated mycelium of the soil fungus Alternaria alternata

We examined collembolan food preference for fungal mycelium grown on copper-contaminated medium, and the relationship between copper content, food selectivity and collembolan fitness when fed contaminated mycelium.To clarify whether collembolan food selectivity is related to fitness parameters, Folsomia candida were fed mycelium of the dark-pigmented fungus Alternaria alternata grown on medium with different copper concentrations. Copper-contaminated food (fungus grown on 50, 125, 250 and 500 μg Cu g^?1 medium, fresh wt.) was offered together with untreated food for 4 weeks. F. candida fed selectively on the provided mycelium and discriminated clearly between mycelium grown on high and low levels of contamination, distinctly preferring fungus grown on medium with a total copper concentration of 50 and 125 μg g^?1. In contrast, fungus grown on highly contaminated medium (250 and 500 μg g^?1) was avoided. Collembolan food preference generally matched fitness parameters. Reproduction was significantly affected by the total copper concentration of the fungal growth medium. When fed their preferred mycelium, collembolan reproduction was enhanced, whereas a diet of highly contaminated mycelium (250 or 500 μg g^?1) resulted in a strong decrease in reproduction. Adult survival was affected only marginally. Even though heavy metal contamination is a potential stress factor for many soil microarthropods, F. candida is able to discriminate between high and low quality food sources, and even benefits from moderately elevated copper concentrations.     

马兰挥发性成分研究

将马兰植株用水蒸气蒸馏所得的挥发油 ,通过气相色谱—质谱分析 ,结合计算机检索技术对其化学成分进行分离和鉴定 ,应用色谱峰面积归一化法测定出各成分的相对百分含量。最后 ,从马兰中鉴定出了 1 8种成分。