Physiological basis of different allelopathic reactions of cucumber and figleaf gourd plants to cinnamic acid

To provide an insight into the mechanism of interspecific interactions mediated by allelochemicals, cucumber and figleaf gourd seedlings were compared on their response to cinnamic acid, an autotoxin from root exudates of cucumber. Reactive oxygen species metabolism and plasma membrane H(+)-ATPase activity were examined in roots upon exposure to cinnamic acid. This exposure resulted in significant increases in activities of NADPH oxidase, superoxide dismutase, guaiacol peroxidase, and catalase, as well as in O(2)(.-) production and H(2)O(2) content, in cucumber roots but not in figleaf gourd roots. Notably, the cucumber roots produced significant amount of reactive oxygen species (ROS) immediately after cinnamic acid treatment, consequently increasing membrane peroxidation, decreasing membrane H(+)-ATPase activity, and losing root viability. By contrast, no such changes were observed in figleaf gourd roots. All these results indicated that there was an interspecies difference in the recognition of allelochemicals, which induced oxidative stress accompanied by root cell death in cucumber, an autotoxic plant, but not in figleaf gourd, a cucumber relative.     

A pegylated derivative of alpha-galactosylceramide exhibits improved biological properties

The glycolipid alpha-galactosylceramide (alphaGalCer) has immunomodulatory properties, which have been exploited to combat cancer, chronic inflammatory diseases, and infections. However, its poor solubility makes alphaGalCer a suboptimal compound for in vivo applications. In this study, a pegylated derivative of alphaGalCer is characterized, which exhibits improved physical and biological properties. The new compound, alphaGalCerMPEG, is water-soluble and retains the specificity for the CD1d receptor of alphaGalCer. The in vitro stimulatory properties on immune cells (e.g., dendritic cells and splenocytes) are maintained intact, even when tested at a 33-fold lower concentration of the active moiety than alphaGalCer. NK cells isolated from mice treated with alphaGalCerMPEG also had stronger cytotoxic activity on YAC-1 cells than those obtained from animals receiving either alphaGalCer or CpG. Intranasal immunization studies performed in mice showed that alphaGalCerMPEG exerts stronger adjuvant activities than the parental compound alphaGalCer when tested at 0.35 vs 11.7 nM/dose. Coadministration of beta-galactosidase with alphaGalCerMPEG resulted not only in high titers of Ag-specific Abs in serum (i.e., 1:512,000), but also in the stimulation of stronger Th2 and secretory IgA responses, both at local and remote mucosal effector sites (i.e., nose, lung, and vagina). The new synthetic derivative alphaGalCerMPEG represents a promising tool for the development of immune interventions against infectious and noninfectious diseases.     

IBV S1基因和IL-2基因双顺反子DNA疫苗的免疫原性研究

为了研制更加有效的IBV DNA疫苗,将IBV的S1基因和禽白介素2(IL-2)基因插入双顺反子表达载体pIRES-EGFP/DsRed中,构建能分别或同时表达S1基因和IL-2基因的pIRES-S1、pIRES-IL2、pIRES-S1/IL-2质粒。通过脂质体转染Vero细胞,利用RT-PCR及间接免疫荧光检测表达。将构建的质粒用脂质体包裹后,通过腿部肌肉多点注射免疫7日龄雏鸡,二免后两周用IBV肾型强毒进行攻毒。结果表明,pIRES-S1/IL-2在体外能够诱导Vero细胞表达S1蛋白和IL-2;pIRES-S1/IL-2和pIRES-S1 pIRES-IL2免疫雏鸡后均能促进外周血T淋巴细胞亚群数量和血清中特异性抗体水平的增加,能明显增强IBV DNA疫苗对同型强毒的攻击保护,但pIRES-S1/IL-2免疫组要优于pIRES-S1 pIRES-IL2混合免疫组及其它对照组,差异显著或极显著。以上结果表明禽IL-2能同时加强DNA疫苗的细胞免疫和体液免疫应答;但抗原基因和IL-2共表达DNA疫苗的免疫效果明显要优于混合注射的DNA疫苗。     

基于26S rDNAD1/D2区序列分析的15株白地霉分子分类学研究

采用26S rRNA基因D1/D2区系统发育分析的方法对CICC(中国工业微生物菌种保藏管理中心)保藏的15株白地霉(Geotrichum candidum)菌种进行复核鉴定。系统发育分析结果表明15株白地霉属于地霉属的成员,且形成两个系统发育分支,系统发育上最接近Galactomyces geotrichum NRRLY-17569T,与其同源性为96.3%～98.3%。15株白地霉26S rRNA基因D1/D2区序列显著不同于地霉属的模式种及其它种,可能代表地霉属的两个新种,但这一结论尚需进一步的实验去证实。     

维生素E对TCDD染毒小鼠白细胞介素和T细胞亚群的影响

为研究维生素E(VE)对2,3,7,8四-氯代二苯并-对-二噁英(TCDD)染毒雄性小鼠白细胞介素(IL)和T细胞亚群的影响,我们设计了5个实验组,将40只小鼠随机分为5组,5组动物给予TCDD和维生素E的水平依次为:TCDD 0 ng/kg和VE0 mg/kg、TCDD 100 ng/kg和VE0 mg/kg、TCDD 100 ng/kg和VE20 mg/kg、TCDD 100ng/kg和VE100 mg/kg、TCDD 100 ng/kg和VE500 mg/kg。灌胃7周后取其血液和脾脏,用酶联免疫法测小鼠血清IL的水平,用流式细胞仪法测定脾脏T淋巴细胞亚群的变化。结果表明:TCDD染毒组小鼠血清IL-1α水平明显高于对照组;VE20 mg/kg和100 mg/kg的两组,其血清IL-1α水平均明显低于染毒组;而VE500 mg/kg组,其血清IL-1α水平与染毒组间差异没有统计学意义;TCDD染毒组小鼠血清IL-2水平明显低于对照组;VE100 mg/kg和500 mg/kg两组,其血清IL-2水平明显高于染毒组;TCDD染毒组CD4 T淋巴细胞百分比明显低于对照组;给予VE的三组,其脾CD4 T淋巴细胞百分比与TCDD染毒组相比有升高的趋势,但没有统计学意义;TCDD染毒组小鼠脾CD8 T淋巴细胞百分比明显高于对照组;VE为100 mg/kg组,其脾CD8 T淋巴细胞百分比明显低于染毒组和VE20 mg/kg两组;VE500 mg/kg组,其脾CD8 T淋巴细胞百分比明显低于染毒组。表明TCDD能导致机体白细胞介素分泌的紊乱以及脾脏T淋巴细胞亚群的变化,而适当剂量的VE对TCDD所致的毒性有拮抗作用。     

弄岗黑叶猴的日活动类型和活动时间分配

2005年10月-2006年9月,用瞬时扫描法对广西弄岗自然保护区内的一群黑叶猴(Trachypithecusfran oisi)的日活动节律和活动时间分配进行研究。结果表明:黑叶猴日活动中出现2个觅食高峰和1个休息高峰。觅食高峰分别出现在7:00-9:00和16:00-18:00;休息高峰出现在10:00-14:00。黑叶猴日活动节律表现出明显的季节性变化,表现为旱季上午的觅食高峰被推迟了1h,且觅食时间长于雨季;旱季下午的觅食活动提前1h结束。猴群在雨季较早进入休息高峰,而且中午休息时很少有移动或零星觅食。研究期间,猴群用于休息的时间平均占日活动时间分配的51.99%,移动占20.25%,觅食占18.61%,理毛占7.61%,玩耍占1.20%,其它行为(包括打斗、交配等)仅占0.14%。活动时间分配有明显的季节性差异,主要表现为:与雨季相比,黑叶猴在旱季花费更多的时间用于觅食和移动,而相应地减少用于休息的时间。活动时间分配在不同年龄和性别的个体之间也存在显著差异,表现为成年个体花费更多的时间用于休息和觅食,未成年个体则花费更多的时间用于移动和玩耍;雌性个体比雄性个体花费更多的时间用于理毛。     

Facile determination of DNA-binding nuclear factor-kappaB by chemiluminescence detection

A simple, rapid, and sensitive method for the assay of a sequence-specific DNA-binding protein, nuclear factor-kappaB (NF-kappaB), has been developed by using a DNA-detectable chemiluminogenic reagent and a centrifugal filter that distinguishes different molecular sizes. After the formation of a complex between NF-kappaB and DNA, the unbound DNA is separated from the complex by the centrifugal filter. The amount of the bound NF-kappaB is estimated by chemiluminescence detection of the bound DNA. This detection is performed within 2 min at room temperature by the use of a chemiluminogenic reagent, 3',4',5'-trimethoxyphenylglyoxal, which selectively recognizes guanine moiety in oligonucleotides or DNAs. This method does not require any labeled probes or antibodies and can determine a concentration as low as 5 nM of DNA-binding NF-kappaB. The sensitivity is nearly the same as that of other methods such as gel shift assay using fluorescence-labeled probes and enzyme-linked immunosorbent assay. Therefore, the current method provides a convenient tool for surveying various DNA-binding proteins.     

靛红衍生物的合成及其对稻瘟菌的生物活性

以靛红为原料合成了系列3-亚胺基/亚甲基-吲哚-2-酮化合物及其Mannich碱衍生物,研究了它们在抗稻瘟菌方面的活性,发现了这两种类型的若干化合物有较好的抑制稻瘟菌孢子萌发的活性,初步讨论了构效关系。认为1位的羟甲基和胺甲基、3位的亚甲基是药效团,芳基亚甲基苯环上对位取代基、羟基取代基和吸电子取代基不利于活性的提高,邻位的供电子取代基有利于活性的提高。     

云县罗扎河下游落叶季雨林的群落生态学研究

对罗扎河下游鲜为人知的落叶季雨林进行了群落生态学研究,结果表明:罗扎河下游落叶季雨林群落高度在15~20m之间;群落乔木层以厚皮树(Lannea coromandelica)、一担柴(Colonafloribunda)、粗糠柴(Mallotus philippensis)、毛果扁担杆(Grewia eriocarpa)、灰毛浆果楝(Cipadessa cinerascens)等树种为优势种;灌草层以刚莠竹(Microstegiumciliatum)盖度最大,其余如飞机草(Eupatoriumodoratum)、藿香蓟(Agera-tumconyzoides)、蹄盖蕨(Athyriumsp.)等种的盖度也比较大;群落中乔木和附生、藤本植物种类较少,而灌木和草本植物种类较多;多数乔木层植株胸径在5~10cm之间,大径级乔木比较少,即使群落中的优势种也主要是通过较多数量的中小径级个体体现出来。多样性指数计算表明,本落叶季雨林的生物多样性指数虽然比典型热带山地雨林为低,但大致相当于季风常绿阔叶林。     

西畴青冈——贵州壳斗科一新记录种

报道了贵州壳斗科植物一新记录种——西畴青冈,并进行了补充描述,同时对该种的生存现状进行评价。