Secophnane-type alkaloids from Daphniphyllum oldhami

Four new alkaloids, daphnioldhanins D-G (1-4, resp.), together with five known alkaloids, daphmacropodine (5), secodaphniphylline (6), deoxycalyciphylline B (7), deoxyisocalyciphylline B (8), and daphmanidin A (9), were isolated from the roots of Daphniphyllum oldhami. Their structures were elucidated on the basis of spectroscopic data and chemical methods. Compound 1 at 2.0 microM showed potent antioxidant activity against H(2)O(2)-induced impairment in PC12 cells.     

Flavone and isoflavone derivatives of terrestrial plants as larval settlement inhibitors of the barnacle Balanus amphitrite

To determine whether they could serve as non-toxic or less damaging alternative antifouling (AF) agents, 17 flavone and isoflavone derivatives were isolated from terrestrial plant extracts, purified and examined for their ability to inhibit the settlement of barnacle (Balanus amphitrite) cyprids. In larval bioassays, eight compounds showed strong anti-larval settlement activities, with EC(50) values <10 microg ml(-1). Through an analysis of the structure-activity relationship of these compounds, it was found that (1) the structural difference between flavones and isoflavones did not affect their AF activities; (2) the 5-hydroxyl group on the skeletons played a key role in AF activities; and (3) the presence of hydroxyl group or bulky group on C3 significantly reduced AF activities. A hydrolysis experiment using genistein, a typical active compound in this study, indicated that it was decomposed in the marine environment by hydrolysis reaction and that the degradation speed was significantly affected by pH. In a field AF test, genistein inhibited the attachment of B. amphitrite on panels coated with genistein-paint mixtures.     

Climate‐driven speedup of alpine treeline forest growth in the Tianshan Mountains,Northwestern China

Forest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration of Picea schrenkiana forest growth since 1960s in the ATE of Tianshan Mountains, northwestern China by a stand‐total sampling along six altitudinal transects with three plots in each transect: one from the ATE between the treeline and the forest line, and the other two from the CFB. All the sampled P. schrenkiana forest patches show a higher growth speed after 1960 and, comparatively, forest growth in the CFB has sped up much slower than that in the ATE. The speedup of forest growth at the ATE is mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition within the CFB might have restricted forest growth there more than that within the ATE, implying biotic factors were also significant for the accelerated forest growth in the ATE, which should be excluded from simulations and predictions of warming‐induced treeline dynamics.     

Effects of a moderate-intensity static magnetic field and adriamycin on K562 cells

The aim of this study was to investigate whether a moderate‐intensity static magnetic field (SMF) can enhance the killing effect of adriamycin (ADM) on K562 cells, and to explore the effects of SMF combined with ADM on K562 cells. We analyzed the metabolic activity of cells, cell cycle distribution, DNA damage, change in cell ultrastructure, and P‐glycoprotein (P‐gp) expression after K562 cells were exposed continuously to a uniform 8.8 mT SMF for 12 h, with or without ADM. Our results showed that the SMF combined with ADM (25 ng/ml) significantly inhibited the metabolic activity of K562 cells (P < 0.05), while neither ADM nor the SMF alone affected the metabolic activity of these cells. Cell ultrastructure was altered in the SMF + ADM group. For example, cell membrane was depressed, some protuberances were observable, and vacuoles in the cytoplasm became larger. Cells were arrested at the G2/M phase and DNA damage increased after cells were treated with the SMF plus ADM. ADM also induced the P‐gp expression. In contrast, in the SMF group and SMF + ADM group, the P‐gp expression was decreased compared with the ADM group. Taken together, our results showed that the 8.8 mT SMF enhanced the cytotoxity potency of ADM on K562 cells, and the decrease in P‐gp expression may be one reason underlying this effect. Bioelectromagnetics 32:191–199, 2011. © 2010 Wiley‐Liss, Inc.     

QTL underlying the resistance to soybean aphid (<Emphasis Type="Italic">Aphis glycines</Emphasis> Matsumura) through isoflavone-mediated antibiosis in soybean cultivar ‘Zhongdou 27’

Soybean aphid (Aphis glycines Matsumura) results in severe yield loss of soybean in many soybean-growing countries of the world. A few loci have been previously identified to be associated with the aphid resistance in soybean. However, none of them was via isoflavone-mediated antibiosis process. The aim of the present study was to conduct genetic analysis of aphid resistance and to identify quantitative trait loci (QTL) underlying aphid resistance in a Chinese soybean cultivar with high isoflavone content. One hundred and thirty F_5:6 derived recombinant inbred lines from the ‘Zhongdou 27’ × ‘Jiunong 20’ cross were used. Two QTL were directly associated with resistance to aphid as measured by aphid damage index. qRa_1, close to Satt470 on soybean linkage group (LG) A2 (chromosome 8), was consistently detected for 3- and 4-week ratings and explained a large portion of phenotypic variations ranging from 25 to 35%. qRa_2, close to Satt144 of LG F (chromosome 13), was detected for 3- and 4-week ratings and could explain 7 and 11% of the phenotypic variation, respectively. These two QTL were highly associated with high isoflavone content and both positive alleles were derived from ‘Zhongdou 27’, a cultivar with higher isoflavone content. The results revealed that higher individual or total isoflavones contents in soybean lines could protect soybean against aphid attack. These two QTL detected jointly provide potential for marker-assisted selection to improve the resistance of soybean cultivars to aphid along with the increase of isoflavone content.     

多层螺旋CT在诊断小儿急性阑尾炎中的应用

目的:探讨多层螺旋CT对小儿急性阑尾炎的诊断价值。方法:回顾分析经临床手术病理证实的53例小儿急性阑尾炎的CT表现特点。所有患儿均行多排CT横断面扫描及MPVR重建。结果:53例中,单纯性阑尾炎2例;急性化脓性阑尾炎伴周围炎4例,其中1例合并紫癜;急性化脓性阑尾炎伴穿孔33例,其中1例合并回肠末端美克尔憩室;坏疽性阑尾炎伴穿孔6例;阑尾脓肿8例。CT平扫以及MPVR重建显示阑尾肿大、增粗(直径大于6mm)30例,阑尾内粪石27例,阑尾周围蜂窝织炎23例,阑尾周围脓肿8例,大量腹水6例。结论:多层螺旋CT扫描及重建技术能为小儿阑尾炎的诊断提供有力依据,提高临床术前诊断能力。