Polysaccharides and Bioactive Phenolics from Aconitum septentrionale Roots

Aconitum septentrionale is known to contain toxic diterpene alkaloids, while other bioactive compounds in the plant remain unclear. The aim of this study was to explore the phenolic compounds and polysaccharides from the water extract of A. septentrionale roots. Fifteen phenolic compounds were isolated and identified by NMR and MS, including fourteen known and one new dianthramide glucoside (2-[[2-(β-D-glucopyranosyloxy)-5-hydroxybenzoyl]amino]-4,5-dihydroxybenzoic acid methyl ester, 14 ). One neutral (complex of glucans with minor amounts of mannans) and two acidic polysaccharide fractions (complexes of pectic polysaccharides and glucans) were also obtained. Hydroxytyrosol ( 1 ), hydroxytyrosol-1-O-β-glucoside ( 2 ) and bracteanolide A ( 7 ) inhibited the release of nitric oxide by dendritic cells. Magnoflorine ( 8 ) and 2-[[2-(β-D-glucopyranosyloxy)-5-hydroxybenzoyl]amino]-5-hydroxybenzoic acid methyl ester ( 12 ) inhibited 15-lipoxygenase, and bracteanolide A ( 7 ) was a moderate inhibitor of xanthine oxidase. This study is the first to describe the diversity of phenolics and polysaccharides from A. septentrionale and their anti-inflammatory and anti-oxidant activities.     

心肌梗塞的肤纹学研究

本文报道了230例心肌梗塞病人和237名对照的肤纹学研究结果。手指嵴线计数、指端花纹频率、左手主线A桡侧终点频率和左手大鱼际花纹频率在病人与对照之间差别的显著。172个病人家庭和156个对照家庭手指嵴线计数复合分离分析结果表明,手指总嵴线计数与心肌梗塞的联系可能取决于病人胚胎期环境因素的影响。     

人肌肌酸激酶在SDS溶液中失活与构象变化的比较研究

应用紫外差吸收光谱、荧光发射光谱、ＣＤ先谱等监测手段,研究了ＳＤＳ溶液滴定人肌肌酸激酶时的构象与活力变化的关系。结果表明酶的活力丧失先于以紫外差吸收先谱、荧先发射谱和巯基暴露数目所监测到的构象变化。ＳＤＳ滴定时引起的酶的荧光发射光谱的变化在低滴定度阶段随着ＳＤＳ滴定量的增加,荧光强度下降,发射峰位红移,当ＳＤＳ浓度达到２．１ｍｍｏｌ／Ｌ时,荧光强度增大,继续增加ＳＤＳ滴定量,荧光强度又降低,发射峰位红移直至终态。紫外差吸收光谱随着ＳＤＳ溶液的加入,２８１ｎｍ．２８７ｎｍ和２９２ｎｍ的负差吸收峰增大。ＣＤ光谱结果表明在本实验所用的ＳＤＳ浓度范围内,ＳＤＳ对人肌肌酸激酶的二级结构几乎没有影响。上述结果支持了酶的活性部位构象柔性的观点。     

Conformational study of sequential Lys and Leu based polymers and oligomers using vibrational and electronic CD spectra

Vibrational CD (VCD) and electronic CD (ECD) spectra of some sequential Lys and Leu based oligo- and polypeptides were studied as a function of added salt and (for ECD) as a function of concentration in aqueous solution. For these samples, the VCD spectra can only be measured at relatively high concentrations under which the well-known salt-induced transition to a β-sheet form can be observed for the KL based species, but only the end-state α-helical conformation is obvious for the LKKL based samples. ECD concentration dependence demonstrates that, at high concentration with no added or with added salt, LKKL based oligomers and polymers give α-helical spectra. These data provide evidence of aggregation induced secondary structure formation in an exceptionally simple peptide system. Similarly, the KL based oligomers and polymers give β-sheet like spectra at high concentration or at high salt. These systems further provide model systems under “normal” aqueous conditions that yield VCD band shapes that correlate to the major secondary structural types of polypeptides. They are in substantial agreement with those spectra obtained on homopolypeptides and on proteins, confirming the relative independence of the VCD technique from side-chain and solvent effects. © 1994 John Wiley & Sons, Inc.     

医院空气中细菌与临床感染的关系研究

医院感染已列为国家质量管理的一个重要组成部分,感染菌的来源,主要分内源性菌,即患者自身带的菌又感染了自己。另一种是外源性菌,即外环境包括空气中的细菌、各种物品中的细菌、人员接触等。医院内感染;以呼吸道感染占首位(59％),空气传播是引起感染的重要方面,空气中病原性微生物的污染程度直接决定感染率的高低。为了弄清医院空气中菌群分布情况及从空气中和临床患者中分离出同一类菌的关系,进行了对比实验及耐药性分析,现将结果报告如下。     

嗜热芽孢杆菌XJT9503高温中性蛋白酶的研究──Ⅰ．XJT9503菌的特性

从新疆吐鲁番盆地土壤里分离到一株嗜热芽孢杆菌,代号ＸＪＴ９５０３．能产生胞外高温中性蛋白酶,该菌在旋转式摇床上１１０ｒ／ｍｉｎ,４５℃下培养６０小时,发酵液产酶为５６００单位／ｍｌ,但在４５℃静止培养产酶可达７４００单位／ｍｌ,Ｃａ２＋、Ｍｇ２＋对产酶有明显促进作用,Ｃｕ２＋等抑制产酶。     

人参不同部位皂甙对衰老的人胚肺成纤维细胞影响的细胞化学研究

应用细胞化学的定性、定位,显微分光光度计定量分析的方法,测定人参不同部位皂甙对低代龄和高代龄人胚肺成纤维细胞内多糖类(PAS反应)、酸性非特异性酯酶(ANAE)、碱性磷酸酶(ALP)、酸性磷酸酶(ACP)、单胺氧化酶(MAO)含量的影响,实验结果表明:人参根、果、茎叶皂甙(SRG、SFG、SSLG)使低代龄细胞的多糖类、MAO含量下降或上升,对ANAE台量没有显著影响。但对高代龄细胞,SFG、SRG、SSLG则显著增加了多糖类、ANAE、ALP、ACP的相对含量,同时降低了MAO的含量。本文提示,人参不同部位皂甙均可以提高衰老细胞内多糖类,ALP、ACP、ANAE的相对含量,降低MAO的含量,而对年青细胞的影响则很不一致。     

聚氨酯塑料的微生物降解

未被合理处置的废塑料污染已成为全球性的环境问题,探索塑料废弃物的无害化处理技术势在必行。近来,研究证实了自然界中存在可以降解塑料的微生物及酶。利用微生物或酶对废塑料进行生物处理成为可能。聚氨酯塑料(Polyurethane,PUR)是广泛应用的通用塑料之一,其废弃物量已占到所有废塑料总体积的30%。文中将PUR塑料发明应用70年来有关微生物降解的研究进行了全面综述,对PUR塑料降解真菌、细菌、降解基因与酶、降解产物及相关的生物处理技术系统等进行了总结与分析,并对实现PUR废塑料高效生物处理需解决的关键科学问题进行了展望。     

Macromolecular Toxins Secreted by <Emphasis Type="Italic">Botrytis cinerea</Emphasis> Induce Programmed Cell Death in Arabidopsis Leaves

Botrytis cinerea causes grey mold disease in crops and horticultural plants. It is suspected to kill plant cells via secreted toxins and to derive nutrients from dead or dying cells. However, whether macromolecular phytotoxins (MPs) secreted by B. cinerea induce necrosis or also trigger a programmed cell death (PCD) remains to be determined. We have previously partially characterized MPs secreted by B. cinerea. Here we isolated MPs from B. cinerea culture and applied them to leaf cells, assessing PCD over the following 120 h. Cell death was assessed by propidium iodide (PI) and 4′,6-diamidino-2-phenylindole (DAPI) staining. Catalase (CAT), peroxidase (POD) activity and the cytochrome c/a ratio were assessed by spectrophotometer. POD isomers were measured using the benzidine acetate method. In Arabidopsis thaliana (L.) Heynh. exposed to B. cinerea MPs, we observed chromatin condensation and marginalization, nuclear substance leakage and accumulation of autofluorescent materials in the cell wall. Furthermore, B. cinerea MPs induced release of cytochrome c from the mitochondria into the cytosol. Moreover, CAT and POD activity was upregulated and the POD isoenzyme pattern was altered. In conclusion, A. thaliana exposed to B. cinerea MPs exhibits multiple hallmarks of PCD, suggesting that B. cinerea induces PCD in host cells through secreted macromolecules.     

Investigation of Optical Spectrum Properties of Hexagonal Boron Nitride from Metal to Dielectric Transition

Plasmonics - Hexagonal boron nitride as a natural hyperbolic material has attracted lots of attention recently. Here, we investigate numerically the optical spectrum properties of hexagonal boron...