Enhancement of fluoride activity against Streptococcus mutans biofilms by a substance separated from Polygonum cuspidatum

Polygonum cuspidatum is a plant with spreading rhizomes and numerous reddish-brown stems that has been used in Korean folk medicine to improve oral hygiene. Nevertheless, there are no reports related to its possible effect on the virulence of dental biofilms. In this study, the ability of a fraction (F1) separated from P. cuspidatum, alone or in combination with fluoride, to disrupt virulence factors and the composition of Streptococcus mutans biofilms was examined. F1 was mainly composed of resveratrol, emodin and physcion (approximately 16.2%, 18.9% and 2.07% of the weight of F1, respectively). F1 showed inhibitory effects on acid production and F-ATPase activity of S. mutans in biofilms, and could enhance fluoride activity against acid production and acid tolerance of S. mutans in biofilms. When S. mutans biofilms were briefly treated with F1 (10 min, a total of five times), the biomass accumulation, water-insoluble polysaccharides and intracellular iodophilic polysaccharides were reduced. Furthermore, the fluoride activity against biomass accumulation was enhanced by F1. These results suggest that F1 may be useful in the control of dental biofilms and in improving the cariostatic properties of fluoride without increasing its exposure.     

Effects of Chemical Components on the Browning of Tomato Juice

The effects of eleven components in tomato juice on browning by heating were examined at the concentrations found in juice, About 70% of the browning of tomato juice was attributable to three constituents; fructose, galacturonic acid and glutamic acid. The interaction between glutamic acid and galacturonic acid or fructose was also found to accelerate the browning of tomato juice. The browning by heating of galacturonic acid with or without amino acids was larger than that of sugars or amino acids. The browning mechanism of galacturonic acid on heating at high temperature was discussed.     

土壤pH值对何首乌生理及其光合特性和有效成分含量的影响

该研究采用盆栽试验,探究不同土壤pH (4.5、5.5、6.5、7.5、8.3、9.5)对何首乌生长、生理特性及有效成分含量的影响,以明确何首乌种植的适宜土壤pH。结果表明：(1)何首乌在土壤pH 6.5~9.5时能正常生长,在pH 4.5和5.5时出现叶片枯萎脱落,少数不能存活;叶面积在pH 4.5～9.5范围内先增加后降低,并在pH 6.5和7.5达到高峰值,且显著高于其余处理。(2)在土壤pH 4.5~9.5范围内,何首乌叶片叶绿素含量、净光合速率、气孔导度和蒸腾速率均呈现先增加后降低的趋势,并在pH 6.5和7.5时达到峰值;叶片脯氨酸、可溶性糖和可溶性蛋白含量总体上随pH升高呈降低趋势;叶片丙二醛含量随pH升高先降低而后增加,其超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均随pH升高先升高后降低。(3)在土壤pH 4.5~9.5范围内,何首乌块茎有效成分含量随pH升高而降低,但均达到《中华人民共和国药典》标准,其中二苯乙烯苷含量和结合蒽醌含量分别为1.89% ～ 5.41%和0.10% ～ 0.25%;土壤pH为4.5时,何首乌块茎中二苯乙烯苷和总蒽醌含量达到最高,分别为5.41%和0.38%。研究认为,何首乌对土壤酸碱有一定的耐受性,但在进行何首乌人工驯化和种植时要尽量避免强酸性环境,且宜选择pH在6.5 ～ 8.3的中性至弱碱性土壤。     

Studies on the Lignans of Polygonum orientale

Three lignans were isolated from the aerial parts of Polygonum orientale L. Their structures were elucidated as arctiin (1), lappaol B (2), orientalin (3) by means of the spectral data and chemical methods. Among them, 3 is a novel compound, compounds 1 and 2 were first found in this plant.     

An unusual homoisoflavanone and a structurally-related dihydrochalcone from Polygonum ferrugineum (Polygonaceae)

The homoisoflavanone 5,7-dihydroxy-6-methoxy-3-(9-hydroxy-phenylmethyl)-chroman-4-one (1) and its structurally related 2',4',6'-trihydroxy-3'-methoxy-alpha-hydroxymethyl-beta-hydroxy-dihydrochalcone (2) along with the known pashanone (3), flavokawin B (4) and cardamonin or alpinetin chalcone (5) pinostrobin (6) and 5,8-dimethoxy-7-hydroxychroman-4-one (7) were isolated from dry leaves of Polygonum ferrugineum (Polygonaceae). To our knowledge, this is the first report of the isolation of a homoisoflavanone from the Polygonum genus and the Polygonaceae family, and could be an important chemotaxonomic finding. In addition, the pattern of substitution of this homoisoflavanone is different from others previously reported.     

传统中药何首乌组织培养的初步研究

主要对何首乌块根和幼茎进行了愈伤组织培养,并对何首乌不同外植体的诱导时间进行了比较.结果表明：诱导何首乌块根产生愈伤组织的最佳激素配比是0.1 mg/L 6-BA＋3.0 mg/LIAA＋0.5 mg/L 2,4-D,且这3种激素的作用主次为2,4-D＞IAA＞6-BA;在此次实验中还比较了不同消毒剂及其组合对何首乌块根的消毒效果,结果表明：70%的酒精＋0.1%HgCl2具有很好的消毒作用.     

Restoration of Species‐Rich,Nutrient‐Limited Mountain Grassland by Mowing and Fertilization

Mowing and management to reduce nutrient levels have often been successfully used to restore species‐rich grasslands in various parts of Europe. However, such treatments have failed to restore the species‐rich Central European mountain grasslands dominated by Polygonum bistorta. P. bistorta builds an extensive underground rhizome system that monopolizes available nutrients in these nutrient‐poor grasslands, enabling this species to persist at high densities even in the presence of mowing. Therefore, we tested a restoration approach using a factorial combination of fertilization and mowing, as well as a litter removal treatment. The experiment was run over 5 years and species composition response to these treatments was recorded at two spatial scales. Mowing suppressed flowering and cover of P. bistorta and promoted target grassland species and richness. Fertilization prevented nutrient impoverishment and increased height and dominance of the broad‐leaved grasses with which many species‐rich grassland herbs could coexist. The additive effect of the mowing/fertilization treatments was strong enough to act as a driver of P. bistorta suppression and associated community change. The litter removal treatment, however, had little effect on plant composition. The experiment demonstrates that in nutrient‐limited grasslands, increasing nutrient levels in addition to mowing to manage competition for light can be used to control dominants. This contrasts with restoration of systems where after abandonment increased nutrient levels lead to the establishment of tall dominants that suppress other species by competition for light.     

昆虫拒食剂蓼二醛的合成及其对害虫的拒食活性

以 β-环柠檬醛为原料 ,经 6步合成了蓼二醛 ( ( -) -polygodial)的消旋体 ,总收率为 1 9 8% ;并合成了其甲胺衍生物。经生物活性测定 ,辣蓼的粗提物和合成的蓼二醛及其甲胺的衍生物对蚜虫和菜青虫有很好的拒食活性     

珠芽蓼果实化学成分研究

利用硅胶柱层析分离和Sephadex LH20纯化等方法从珠芽蓼果实分离得到6个化合物,经^1H NMR、^13C NMR等技术及理化性质鉴定为β-谷甾醇、胡萝卜苷、没食子酸、正丁基—β—D吡喃果糖苷、槲皮素—5—O—β—D—葡萄糖苷、蔗糖。6种化合物均为首次从该植物分离得到。     

盐胁迫下西伯利亚蓼6个时期混合叶cDNA文库的构建和初步分析

以3％NaHCO3胁迫处理西伯利亚蓼2h、6h、12h、1d、2d和3d共6个时期混合叶为材料,提取总RNA。根据Stratagene公司cDNA建库试剂盒构建了西伯利亚蓼混合叶cDNA文库。原始文库滴度为2．0×10^6pfu·mL^-1,扩增后文库滴度为4．5×10^9pfu·mL^-1,重组率为95．9％,插入片段大小在0．3—1．5kb之间,平均长度为0．45kb左右。经测序获得2575个EST序列,拼接出1977个假定独立转录本（TUTs）,其中文库中含有大量低丰度表达基因,约占TUTs总数的89．58％。BlastX分析表明,1977个TUTs中共有720个TUTs有明确功能注释,其中参与胁迫过程中代谢、能量、光合作用和蛋白合成基因表达量较高,而涉及转录、信号转导、细胞防御和救援基因表达量较低。