从烟草丛顶病病原复合物中分离烟草扭脉病毒的方法

烟草丛顶病是由烟草丛顶病毒（TBTV）、烟草丛顶病毒类似卫星RNA（Sat-TBTV）、烟草扭脉病毒（TVDV）和烟草扭脉病毒相关RNA（TVDVaRNA）复合侵染引起的一类特殊病害,目前尚不清楚这些病原物各自在病害症状形成和病害传播中的作用。本文根据蚜虫传播烟草丛顶病复合病原物传毒特性的差异,探索了3种分离TVDV的生物学方法。方法A为将获得了烟草丛顶病复合病原物的蚜虫饥饿24h后,以单虫单苗的方式接到健康烟株上传毒,24h后灭虫。方法B为将无毒蚜虫饥饿2-4h后转接到感病烟株上饲毒48h,再以单虫单苗的方式接到健康烟株上传毒,24h后灭虫。方法C为将无毒蚜虫于感病烟株上饲毒48h后,以单虫单苗的方式接到健康烟株上传毒24h,此后每隔24h将蚜虫移到另一健康烟株上传毒,直到蚜虫死亡。其中方法 A和B均可将TVDV从烟草丛顶病病原复合体中分开,方法A操作简单、分离周期短且TVDV的分离效率高。单独TVDV侵染的烟株无明显的丛顶症状,叶片靠近主脉的地方会出现皱缩,生长后期叶片变得细长且顶端会发生扭曲。本试验可为研究TVDV与其他病原物、寄主植物和传播介体的相互作用提供很好的试验材料,也可为蚜虫传播的复合侵染病毒的生物学分离提供参考。

黑龙江省大豆花叶病毒(SMV)株系的动态变化分析

2012年大豆花叶病毒(SMV)病发病盛期,在我国黑龙江省大豆主产区的哈尔滨、绥化、黑河、齐齐哈尔、佳木斯和牡丹江市的68块大豆生产田、国营农场及部分科研单位的试验田采集病样461份,经在感病大豆品种南农1138-2上初步繁殖鉴定、单斑分离纯化和血清学鉴定,最终获得阳性SMV单一分离物63个。采用一套共10个大豆鉴别寄主鉴定了63个分离物在鉴别寄主上的反应,发现63个分离物分属2个SMV致病型。其中6个(9.5%)分离物属SC15株系,57个(90.5%)分离物属SC18株系。发现黑龙江省SMV株系组成较简单,强毒株系SC15零星发生,弱毒株系SC18为优势株系且分布较广。与以往鉴定结果比较,发现SC15与吕文清等鉴定的东北3号株系致病性相近,SC18与东北1号株系相近。建议黑龙江省大豆SMV防控和大豆抗病育种应以优势SMV株系SC18为主,并兼顾强毒株系SC15。

Study on Screening of Fungi with High-resistance against Chromium and on Related Characteristics

[Objective] The aim was to separate chromium-resistant microorganism from soil contaminated by chromium.[Method] Separation and purification technique was used as follows：different concentrations of Cr^6＋ were added into medium,and chromium-resistant fungi were screened after separations and domestications.The selected fungi were under preliminary identification according to its morphological and colony characteristics.Then,related biological characteristics were studied,including measurement of growth curve,growing effects by temperature,pH value and osmotic pressure.[Result] The Cr（VI） with concentration of 1 000 mg/L was separated and selected from soils in ten different places contaminated seriously by heavy metal in adjacent region of Yulin City.Considering its morphological and colony characteristics,it was preliminarily identified as saccharomycetes,which can well grow within 15-37 ℃,and whose most suitable temperature was 28℃.Bacterial strain can grow well with pH of 4-10,and the optimum pH was 7.2;besides,it can grow well with NaCl concentration of 0.5%-5.0%.Through the experiment,the bacteria was found with resistance not only to chromium,but also to heavy metals such as Pb＋Cu,Cu＋Fe,Pb＋Fe,and Pb＋Cu＋Fe.[Conclusion] The fungi selected from the experiment were of good adaptability to natural environment,and it also had resistance to other heavy metals.

Recover vigorous cells of Magnetospirillum magneticum AMB-1 by capillary magnetic separation

Cultivable magnetotactic bacteria(MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic studies.However,a cold-stored MTB strain,such as Magnetospirillum magneticum AMB-1,often loses its ability to synthesize magnetosomes and consequently fails to sense the external magnetic field.It is therefore important to quickly recover vigorous bacteria cells that highly capable of magnetosome producing.In this study,a modified capillary magnetic separation system was designed to recover a deteriorating strain of Magnetospirillum magneticum AMB-1 that long-term cold-stored in a refrigerator.The results show that all cells obtained after a 3-cycle treatment were vigorous and had the ability to produce magnetosomes.Moreover,the 3rd-cycle recovered cells were able to form more magnetosome crystals.Compared with the colony formation method,this new method is time-saving,easily operated,and more efficient for recovering vigorous MTB cells.

Isolation and Characterization of Phosphate-Solubilizing Bacteria from Seagrass Rhizosphere Soil

Phosphate-solubilizing bacterial strains(6 Nos.) were isolated from the rhizosphere soils of two seagrasses(Halophila ovalis(R.Br.) Hook and Halodule pinifolia(Miki) Hartog) in the Vellar estuary.Experimental studies found that the strain PSSG6 was effective in phosphate solubilization with Phosphate Solubilization efficiency index E = 375 ± 8.54,followed by the strain PSSG5 with Phosphate Solubilization efficiency index E = 275 ± 27.3.Of the 6 strains isolated,the strains PSSG4 and PSSG5 be-longed to the genus Bacillus,and PSSG1,PSSG2 and PSSG3 were identified as Citrobacter sp.,Shigella sp.,and Klebsiella sp.,respectively,by conventional method,and PSSG6 was identified as Bacillus circulans using conventional and molecular methods.

Simultaneous Cell Disruption and Aqueous Two-Phase Extraction for Isolation of Intracellular Recombinant Proteins

A new technique was developed for the integrated processing of cell disruption and aqueous two-phase extraction in a high-speed bead mill to separate intracellular proteins from microbial cells. The process was named as simultaneous cell disruption and aqueous two-phase extraction (SDATE). Advantages, such as high cell disruption efficiency, biochemical activities preservation of proteins, cell debris elimination, and prelimiary purification of the target protein were being claimed. When this technique was employed for isolating recombinant Tumor Necrosis Factor (TNF) from E. coli, overall protein concentration and TNF activity were found to have been increased. More than 95% of TNF was partitioned into the top phase and all cell debris were in the bottom phase. The partition coefficient was greater than 3 and the TNF purification factor was greater than 6. It is shown that less separation steps were being utilized in the new technique, meaning a reduction in separation time and less process extractors required.

Thermodynamic Analysis of Heavy Metals Biosorption by Two Macroalgae

The thermodynamic process of two macroalgae, Sargassum fusiforme and Laminaria japonica, absorbing heavy metal ions Cu2+, Pb2+, Cd2+ and Ni2+, has been studied. The result indicates that the absorption isotherms of these two macroalgae clearly accord with the Landmuir adsorption model. The absorptive processes of S. fusiforme and L. japonica for Cu2+℃ are endothermal, and at 35 , the adsorption heat of these two algae is 59.5 kJ/mol and 76.8 kJ/mol respectively. Temperature could affect the algae’s adsorption capacity. Their adsorption ℃℃capacity increases with temperature ( 25 and 35 ).

Isolation and Identification of Main Fungal Pathogens in Muskmelon in Open Field of Hubei Province in Summer

Fungal diseases often occur seriously in muskmelon in open field of Hubei Province in summer, especially in continuous cropping pattern, resulting in great economic losses. In this study, the pathogens of main fungal diseases in muskmelon in open field of Hubei Province were isolated, and they were identified by morphological and molecular techniques. The results showed that muskmelon fusarium wilt is a major disease in muskmelon in open field of Hubei Province in summer, and its pathogen was confirmed to be Fusarium oxysporum. In future studies, one pair of specific primers would be designed to detect different pathogenic races of Fusarium oxysporum so as to accelerate the detection and to shorten the detection time,thereby proving guidance for actual production.

Isolation of Main Genes Involved in Flowering of Saffron （Crocus sativus L.） in Order to Study Effective Flowering Protein

Saffron （Crocus sativus L.） always is grown for using its flowers in nutrient industry, color industry and healthy compounds due to its flowers and specially stigmas. Because of its expensive flowers, surveying and recognizing on effective genes for flowering is very important and its results can help us to control rate and timing of flowering at an early stage of flowering. The gene and gene state meant Pistillata like MADS box （PIC2） were surveyed for recognizing its molecular mechanism. The molecular sequence at the genes has high similarity to members of family MADS that is a factor for controls of protein at flowering stage. PIC2 gene was studied by bioinforrnatics resources. Primers were designed for replicating the gene and DNA and RNA were extracted from saffron＇s leaves. The gene＇s eDNA was built by recopying enzyme and used such a pattern for replicating gene PIC2 at polymerase chain reactions （PCR）. Segments were replicated such 900 eDNA pair-nucleotides and a segment such 2,100 of DNA＇s pair-nucleotides. The gene codes a protein that was composed of 210 amino acids that has MADS sequence box. Analysis of protein＇s molecular structure and homological modeling of the protein indicated that it has a regular structure.

Structures and Antiviral Activities of Butyrolactone Derivatives Isolated from Aspergillus terreus MXH-23

A new butyrolactone derivative,namely butyrolactone Ⅷ （1）,and six known butyrolactones （2-7） were separated from the ethyl acetate （EtOAc） extract of the fermentation broth of a fungus,Aspergillus terreus MXH-23.The chemical structures of these metabolites were identified by analyzing their nuclear magnetic resonance （NMR） and mass spectrometry （MS）.Known butyrolactone derivatives contain an α,β-unsaturated γ-lactone ring with α-hydroxyl and y-benzyl,and butyrolactone Ⅷ （1） was the first butyrolactones contains α-benzyl and γ-hydroxyl on α,β-unsaturated lactone ring.All of the butyrolactone derivatives were tested for their anti-influenza （H 1N 1） effects.Derivatives 4 and 7 showed moderate antiviral activities while the newly-identified,derivative 1,did not.

Recent advances in plant centromere biology

The centromere, which is one of the essential parts of a chromosome, controls kinetochore formation and chromosome segregation during mitosis and meiosis. While centromere function is conserved in eukaryotes, the centromeric DNA sequences evolve rapidly and have few similarities among species. The histone H3 variant CENH3(CENP-A in human), which mostly exists in centromeric nucleosomes, is a universal active centromere mark in eukaryotes and plays an essential role in centromere identity determination. The relationship between centromeric DNA sequences and centromere identity determination is one of the intriguing questions in studying centromere formation. Due to the discoveries in the past decades, including "neocentromeres" and "centromere inactivation", it is now believed that the centromere identity is determined by epigenetic mechanisms. This review will present recent progress in plant centromere biology.

The naturally occurring secolignans

Naturally occurring secolignans have drawn the considerable attention because of their novel structures and diverse biological activities.In recent years,various natural secolignans with extensive bioactivities have been reported in the literatures.In the present review,we summarized all the available information regarding the biosynthesis,distributions,separation methods,chemical structures,spectral characteristics,and biological activities of natural secolignans,and provided some valuable new insights for the further study.