常温和低温下保存小新月菱形藻的包埋-脱水法

用包埋.脱水法在常温和低温下保存小新月菱形藻(Nitzschla closterium f.minutissima),探讨了温度、光(暗)、含水量,密封袋内空间体积和密封袋外膜材质等因素对保存效果的影响.结果表明,小新月菱形藻在4℃下暗保存6个月后的最高存活率达到80.4%.而且,保存后的藻细胞经过恢复培养后,其生长力可达到保存前的水平.包埋.脱水法操作简单.无需复杂设备,在藻类种质保存中有广阔的应用前景.     

The role of PilZ domain proteins in the virulence of Xanthomonas campestris pv. campestris

Cyclic di‐GMP [(bis‐(3′–5′)‐cyclic di‐guanosine monophosphate)] is an almost ubiquitous second messenger in bacteria that is implicated in the regulation of a range of functions that include developmental transitions, aggregative behaviour, adhesion, biofilm formation and virulence. Comparatively little is known about the mechanism(s) by which cyclic di‐GMP exerts these various regulatory effects. PilZ has been identified as a cyclic di‐GMP binding protein domain; proteins with this domain are involved in regulation of specific cellular processes, including the virulence of animal pathogens. Here we have examined the role of PilZ domain proteins in virulence and the regulation of virulence factor synthesis in Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot of crucifers. The Xcc genome encodes four proteins (XC0965, XC2249, XC2317 and XC3221) that have a PilZ domain. Mutation of XC0965, XC2249 and XC3221 led to a significant reduction of virulence in Chinese radish. Mutation of XC2249 and XC3221 led to a reduction in motility whereas mutation of XC2249 and XC0965 affected extracellular enzyme production. All mutant strains were unaffected in biofilm formation in vitro. The reduction of virulence following mutation of XC3221 could not be wholly attributed to an effect on motility as mutation of pilA, which abolishes motility, has a lesser effect on virulence.     

Genetic polymorphism of mitochondrial DNA HVS-I and HVS-Ⅱ of Chinese Tu ethnic minority group

We analyzed the two hypervariable segments HVS-Ⅰ and HVS-Ⅱ of 108 Chinese Tu ethnic minority group samples for forensic and population genetics purposes.Comparing with Anderson sequence,79 polymorphic loci in HVS-Ⅰ and 40 in HVS-Ⅱ were found in Chi-nese Tu ethnic minority group mtDNA sequences,and 90 and 64 haplotypes were then defined.Haplotype diversity and the mean pair-wise differences were 0.9903:±0.0013 and 5.7785 in HVS-Ⅰ,and 0.9777±0.0013 and 3.5819 in HVS-Ⅱ,respectively.By analyzing the hypervariable domain from nucleotide 1,6180 to 1,6193 in HVS-Ⅰ,we defined some new types of sequence variations.We also compared the relationship between Tu population and other populations using mtDNA HVS-Ⅰ sequences.According to Rst genetic distances,the phylogenetic tree showed that the Tu population,the Xi'an Han population,the Chinese Korean,and the Mongol ethnic group were in a clade.This indicated a close genetic relationship between them.There were far relations between the Tu population and other Chinese southern Han populations,Siberian,European,African,and other foreign populations.The results suggest that Tu population has a multi-origin and has also merged with other local populations.     

体外重组的人促黄体素对小鼠早期胚胎发育的影响

为了研究人的重组促黄体素（r-hLH)对小鼠早期胚胎发育的作用,我们用一定剂量的r-hFSH(人促卵泡素,20IU）结合不同剂量的r-hLH（0－20IU）,或先与不同剂量r-hLH配比（5－20IU）,再与一定剂量,r-hLH（15IU）结合,对性成熟前的小鼠进行超数排卵;并对从其输卵管冲出的早期胚胎进行体外培养,通过观察这些早期胚胎体外发育情况,再与PMSG－hCG超排小鼠的早期胚胎体外培养结果进行比较。我们发现用重组激素处理的性成熟前小鼠,无论在平均冲胚数或桑囊率,囊胚率上,都以结合r-hLH或配比r-hLH的剂量为15IU时最好,但各重组激素处理组在桑囊率和囊胚率上都极显著低于PMSG－hCG对照组的相应指标。上述结果表明,r-hLH对小鼠早期胚胎的发育（尤其是囊胚的形成）有明显的抑制作用,且与r-hLH呈一定的剂量依赖性关系。     

Regeneration of plants from callus tissues of hairy roots induced by Agrobacterium rhizogenes on Alhagi pseudoalhagi

INTRoDUCTIONThe hairy root disease is a patholOgical syndromeof dicotyledonous plants fOllowing wounding and in-fection with Agrobacterum rhjZOgenesI1]. The rhi-zogenicity is conferred to p1ant cel1s by a fragmentof DNA (Ri T-DNA), which is transferred from thelarge root--inducting (Ri) plasmid, haJrboured by thebacterium, to the genome, where it is stably inte-grated and expressed. Illtegration of a DNA segment(T-DNA) of pRi into the host genome 1eads to ac-tive proliferation of…     

The occurrence and ecological importance of dissolved ATP in fresh water

SUMMARY. Dissolved ATP, defined as ATP which passes through 0.2 μm filters, was found in fresh water. During the spring diatom bloom in two eutrophic Danish lakes, concentrations of dissolved ATP varied between 0.1 and 3.8 μgl⁻¹, constituting 14–76% of the total ATP (particulate plus dissolved ATP). The kinetics of the light emission obtained from mixing firefly enzyme with dissolved ATP demonstrated that the major proportion of the dissolved ATP was in fact ATP. Despite some variations, the seasonal changes in dissolved ATP paralleled the changes in the increasing phytoplankton population during the rise of the diatom blooms. The dissolved ATP increased after the diatom peak, indicating that release of ATP from the phytoplankton due to mortality may be a major source of dissolved ATP.
Consumption of dissolved ATP was evaluated in uptake experiments using ³H-ATP. Rates of uptake of ³H-ATP by micro-organisms (diameter 0.2–0.6 μm) proved to be close to the rates for ³H-D-glucose uptake. The variations in ³H-ATP uptake during the diatom blooms showed non-systematic changes and ranged between 1.0 and 15.8% h⁻¹ (mean = 4.9% h⁻¹) of the quantity added. Turnover rates for dissolved ATP varied between 12 and 730 ng l⁻¹ h⁻¹ (mean = 175 ng l⁻¹). These rather high rates of turnover suggest that dissolved ATP is an important compound in the metabolism of freshwater bacteria.     

中等强度跑台运动预防去卵巢大鼠骨质疏松

目的观察中等强度跑台运动对去卵巢大鼠骨质疏松的预防作用。方法将30只3月龄未经产雌性SD大鼠随机分为假手术、去卵巢静止和去卵巢运动三个组。去卵巢运动组每周进行4次时间45min、速度18m/min、坡度5°的跑台训练。实验结束时,检测血清雌二醇（E2）、碱性磷酸酶（ALP）、抗酒石酸酸性磷酸酶（TRAP）和骨钙素（BGP）水平以及右侧游离股骨和胫骨的骨密度（BMD）和骨矿物含量（BMC）;同时观察左侧股骨远端和胫骨近端组织形态学变化。结果与假手术组比较,去卵巢静止组大鼠血清ALP活性和BGP含量显著升高,血清TRAP活性和E2含量显著下降,股骨近段和远端以及胫骨近端BMD和BMC显著下降,股骨远端和胫骨近端骨小梁断裂增加、数目减少;与去卵巢静止组比较,去卵巢运动组大鼠血清E2和BGP含量显著上升,股骨三个部位以及胫骨近端BMD和BMC显著增加,股骨远端和胫骨近端骨小梁断裂减少、数目增加。结论中等强度跑台运动能增加去卵巢大鼠血清E2和BGP含量,改善去卵巢大鼠骨组织学结构。     

昆虫杆状病毒系统表达口蹄疫病毒3ABC基因

以O型口蹄疫病毒为研究对象,经过RTPCP扩增得到非结构蛋白3ABC基因,克隆到转移载体pFastbacHT,将其转入含穿梭载体Bacmid的DH10Bac,与Bacmid发生位点特异性转座作用,得到3ABC的重组穿梭载体Bacmid3ABC,再将其转染昆虫细胞HiFive。PCR鉴定证实3ABC基因正确地插入到病毒基因组的多角体蛋白基因启动子下游,经过SDSPAGE和Westernblot检测,3ABC基因在昆虫细胞中表达了大小约为50kDa的蛋白条带,3ABC基因在BactoBac系统中的成功表达为建立以基因工程产品为抗原、鉴别诊断自然感染和免疫动物的方法提供了技术条件。     

北京四座楼自然保护区植物区系及植被分析

通过样地法对北京市四座楼自然保护区的植被进行了调查,在本底调查的基础上分析了四座楼自然保护区维管植物的区系成分和植被分布规律：该保护区有北京新记录种1个：麦李（Prunus glandulosa Thunb．）;国家三级保护植物3种,即：紫椴（Tilia amurensis Rupr．）、黄檗（Phellodendron amurense Rupr．）和刺五加[Acanthopanax senticosus（Rupr．et Maxim．）Harms];并分布有较大面积的天然侧柏[Platycladus orientalis（Linn．）Franco]林。该保护区共有维管植物约869种,分别属于127科431属,其中蕨类植物共有16科19属33种,裸子植物共有3科4属4种,被子植物共有108科408属832种,其中野生植物有772种,占北京所具有的野生植物种类的1／3以上。四座楼自然保护区野生种子植物共有15个分布区类型,其中北温带分布类型最多,表明本保护区的植物分布具有温带性质。     

中脑导水管周围灰质内注射抗阿片肽血清对神经降压素增强电针镇痛的影响

本工作以钾离子透入引起大鼠甩尾反应作为痛反应指标,观察纳洛酮（ＮＸ）和抗阿片肽血清对大鼠中脑导水管周围灰质（ＰＡＧ）内微量注射神经降压素（ＮＴ）增强电针镇痛作用的影响。结果显示：（１）ＰＡＧ内微量注射ＮＴ后,大鼠电针镇痛效应明显提高;（２）ＰＡＧ内注射大剂量ＮＸ,可以显著减弱ＮＴ增强电针镇痛效应;（３）ＰＡＧ内微量注射抗甲脑啡肽血清和抗β内啡肽血清后,ＮＴ增强电针镇痛的作用明显降低;而ＰＡＧ内微量注射抗强啡肽Ａ１１３血清,对于ＮＴ增强电针镇痛的作用并无明显影响。提示：ＰＡＧ内ＮＴ在针刺镇痛过程中发挥重要作用,ＮＴ增强电针镇痛的作用与甲脑啡肽和β内啡肽有较密切的关系。