界面发酵红曲霉的图像解析*

利用计算机视觉技术研究了红曲霉界面发酵过程中菌体形态变化与菌体生长的关系。在界面培养中通过检测前期菌落面积,后期隆起部分的表征体积——基于颜色变化的生长点分布,可以有效表示菌体生长状况。基于此建立了含有相应形态参数的动力学模型,该模型与常规动力学模型具有相似的表达形式。     

流行性出血热地鼠肾细胞灭活疫苗人体试用细胞免疫反应观察

观察了20位志愿者在接种试验性流行性出血热(EHF)地鼠肾细胞(GHKC)双价灭活疫苗后的细胞免疫反应,并以其体液免疫反应作对照观察。用淋巴细胞转化试验测定细胞免疫水平。结果首针疫苗接种后42天和56天,特异性刺激指数(SSI)和非特异性刺激指数(NSI)均较免疫前显著增高(P_(SSI)<0.001;P_(NSI)<0.02),免疫后SSI累计阳转率为100％,NSI累计阳转率为60％,免疫后6个月二者均降低至正常水平。免疫后56天测定抗体,荧光抗体阳转率为100％;微量感染性中和试验表明,针对家鼠型病毒L99株中和抗体阳转率为95％,而针对野鼠型病毒JR株阳转率为65％。     

An overview of the highly pathogenic H5N1 influenza virus

Since the first human case of H5N1 avian influenza virus infection was reported in 1997, this highly pathogenic virus has infected hundreds of people around the world and resulted in many deaths. The ability of H5N1 to cross species boundaries, and the presence of polymorphisms that enhance virulence, present challenges to developing clear strategies to prevent the pandemic spread of this highly pathogenic avian influenza (HPAI) virus. This review summarizes the current understanding of, and recent research on, the avian influenza H5N1 virus, including transmission, virulence, pathogenesis, clinical characteristics, treatment and prevention.     

TSG101 promotes the proliferation,migration and invasion of hepatocellular carcinoma cells by regulating the PEG10

The tumour susceptibility gene 101 (TSG101) is reported to play important roles in the development and progression of several human cancers. However, its potential roles and underlined mechanisms in human hepatocellular carcinoma (HCC) are still needed to be further clarified. In the present study, we reported that knock down of TSG101 suppressed the proliferation, migration and invasion of HCC cells, while overexpression of TSG101 facilitated them. Molecularly, the results revealed that knock down of TSG101 significantly decreased the cell cycle related regulatory factor p53 and p21. In another point, knock down of TSG101 also obviously decreased the level of metallopeptidase inhibitor TIMP1 (Tissue inhibitors of metalloproteinases 1), which results in inhibition of MMP2, MMP7 and MMP9. In contrast, overexpression of TSG101 had opposite effects. The iTRAQ proteomics analysis identified that oncogenic protein PEG10 (Paternally expressed gene 10) might be a potential downstream target of TSG101. Further investigation showed that TSG101 interacted with PEG10 and protected it from proteasomal degradation thereby regulating the expression of p53, p21 and MMPs. Finally, we found that both TSG101 and PEG10 proteins are up‐regulated and presented a direct correlation in HCC patients. In conclusion, these results suggest that TSG101 is up‐regulated in human HCC patients, which may accelerate the proliferation, migration and invasion of HCC cells through regulating PEG10.     

Is the removal of aboveground shrub biomass an effective technique to restore a shrub‐encroached grassland?

Encroachment of woody plants into grasslands is a global phenomenon that has substantial impacts on pastoral productivity and ecosystem services. Over the past half century, pastoralists and land management agencies have explored various options to control woody plants in order to improve ecosystem services in shrub‐encroached grasslands. We examined the effectiveness of controlling the encroachment of the shrub Caragana microphylla into grassland in Inner Mongolia, China. We cut and removed all of the aboveground biomass from 450 shrubs, predicting that the effectiveness of this technique to control shrubs would depend on shrub morphology. Specifically, we expected that larger shrubs with more biomass would be more difficult to kill by cutting than smaller shrubs. A year after treatment, we found that cutting killed only 11% of the 450 treated shrubs, and of these, three‐quarters of the locations that they occupied reverted to grasses and one‐quarter to bare soil. Shrubs that survived the cutting treatment produced more stems and leaf biomass, and therefore had a greater leaf to stem ratio. Shrubs that died after cutting had a lower crown area and basal area, and less stem biomass than shrubs that resprouted within 12 months of cutting. There were no effects of shrub height on the fate of treated shrubs. Cutting had no effect on understory plant cover or richness, but reproductive plants were taller under shrubs that were not cut. Overall, our study showed that removing aboveground shrub biomass by cutting is an ineffective technique for “restoring” the original grassland community unless shrubs are very small. Strategic targeting of small shrubs would be a more effective technique for controlling the spread of C. microphylla in the long term.     

武汉东湖星形柄裸藻种群与宿主的关系以及生态因子对它的影响

星形柄裸藻与附生宿主之间的相互作用为:它是偏利者,而对宿主无很大影响;当其在宿主体表大量附着时,才对宿主有偏害作用。它的种群密度(N,个/L)与宿主密度(Na,个/L)有密切的正相关关系:N=0.0858e0.0528Na(r=0921,pT,天)对星形柄裸藻的平均附着量(m,个/每个甲壳动物)和附着量(B,个/L)的影响是:在一定的蜕皮间隔时间范围内呈正相关性:m=aebT和B=aebT(a和b为方程常数,下同);超过这个范围呈负相关性:m=aT-b和B=aT-b。而宿主蜕皮间隔时间(T,天)对星形柄裸藻附着率(R,%)的影响则仅为正相关性:R=a+blnT。星形柄裸藻对宿主的附生有一定的选择性。水温(t,℃)与星形柄裸藻种群密度(N,个/L)的关系为:在5-12℃时呈正相关性,N=0.309e0.624t(r=0.914,pN=0.0000617e190.2/t(r=0.941,pR,%)的影响则仅呈负相关关系:R=bln(30-t)-a。水的透明度(d,cm)与星形柄裸藻种群密度(N,个/L)的相关方程为:N=0.020e0.037d(r=0.838,pS,mg/L)与种群密度(N,个/L)有一定的正相关性:N=0.00254e0.178S(r=0.816,pN,个/L)与4个主要因子:宿主密度(N,个/L),透明度(d,cm),水温(t,℃),含钙量(S,mg/L)的多元回归方程为:N=1.208Na+0.698d+5.584t+2.942S-357.957(R=0.853,df=11,k=4,p<0.01)。       

用ElISA研究稻田节肢类捕食者对稻飞虱的捕食作用

应用酶联免疫吸附试验(ELlSA)来研究捕食作用能较准确地评价捕食性天敌对害虫的控制作用。ELlSA检测表明,不同种类的捕食性天敌对稻飞虱的捕食作用有较大差别,其中以优势种食虫沟瘤蛛和拟水狼蛛的捕食作用最大,阳性反应率与稻飞虱的种群密度有一定的相关关系,但在稻飞虱密度较低的情况下也表现出较高的阳性反应率。     

锦天牛属阳茎内囊结构

采用显微解剖和冰冻组织切片方法研究锦天牛属Acalolepta三种天牛阳茎内囊的结构,发现内囊骨化结构物,尤其端部骨化结构物,及其控制内囊伸缩的加厚侧带和有聚集精子作用的射精管壶腹结构,在探讨天牛科分类和系统发育上均具有重要意义。     

Production of 3-hydroxypropionate homopolymer and poly(3-hydroxypropionate-co-4-hydroxybutyrate) copolymer by recombinant Escherichia coli

Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydroxypropionate) (P3HP), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (P3HP4HB), dhaT and aldD were expressed in E. coli together with the phaC1 gene encoding polyhydroxyalkanoate (PHA) synthase gene of Ralstonia eutropha, and pcs' gene encoding the ACS domain of the tri-functional propionyl-CoA ligase (PCS) of Chloroflexus aurantiacus. Up to 92 wt% P3HP and 42 wt% P3HP4HB were produced by the recombinant Escherichia coli grown on PDO and a mixture of PDO+1,4-butanediol (BD), respectively.