1000 resultados para 5.8SrRNA


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以低等真核生物的5.8SrRNA为材料进行研究. 发现在用今祖法消除了进化速度之差的影响所得到的差异矩阵d'中, 各组理应彼此相等的数值会因核苷酸偶合的影响而成为不等值的. 取各组中各自的的最大值作为受偶合的影响最小者, 以之对今祖法所得到的分枝型式进行校正, 即可得到更为正确的结果. 在此基础上提出了对差异矩阵d'进行最大值成聚以代替原法中的平均值成聚的削偶合今祖法. 新法在结果的正确性、稳定性和一致性上都优于原法。

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从排污沟的废水污泥中筛选到 1株产絮凝剂的霉菌GXF9912。该菌株的最佳产絮凝剂时间为培养后72h ;培养基的初始 pH为 6 .0~ 6 .5时 ,产生的絮凝剂活性较高 ;Ca2 +对絮凝作用有促进作用。通过GXF9912菌株的 5 .8SrRNA基因两侧的内转录间隔区 (internaltranscribedspacers,ITS)进行序列分析表明该菌株为曲霉。

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对青藏高原特有的濒危植物华福花 (SinadoxacorydalifoliaC .Y .Wu ,Z .L .WuetR .F .Huang)的核糖体DNA中的内转录间隔区 (ITS)序列及 5 .8SrRNA基因的序列进行了测定。同川续断目和五加目有关类群序列的比较及分支分析表明华福花属与五福花属 (AdoxaL .)近缘 ,不支持它可能与五加目或败酱科有亲缘关系的假设。尽管形态上它与五福花属分化十分明显 ,但ITS碱基分异却较小。引起其系统位置发生争论的外部形态为什么进化得如此之快 ,是值得进一步深入探讨的课题。

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Raman spectra were recorded in the range 400–1800 cm−1 for a series of 15 mixed \[tetrakis(4-tert-butylphenyl)porphyrinato](2,3-naphthalocyaninato) rare earth double-deckers M(TBPP)(Nc) (M = Y; La–Lu except Pm) using laser excitation at 632.8 and 785 nm. Comparisons with bis(naphthalocyaninato) rare earth counterparts reveal that the vibrations of the metallonaphthalocyanine M(Nc) fragment dominate the Raman features of M(TBPP)(Nc). When excited with radiation of 632.8 nm, the most intense vibration appears at about 1595 cm−1, due to the naphthalene stretching. These complexes exhibit the marker Raman band for Nc•− as a medium-intense band in the range 1496–1507 cm−1, attributed to the coupling of pyrrole and aza stretching, while the marker Raman band of Nc2− in intermediate-valence Ce(TBPP)(Nc) appears as a strong band at 1493 cm−1 and is due to the isoindole stretchings. By contrast, when excited with radiation of 785 nm that is in close resonance with the main Q absorption band of the naphthalocyanine ligand, the ring radial vibrations at ca 680 and 735 cm−1 for MIII(TBPP)(Nc) are selectively intensified and are the most intense bands. For the cerium double-decker, the most intense vibration also acting as the marker Raman band of Nc2− appears at 1497 cm−1 with contributions from both pyrrole CC and aza CN stretches. The same vibrational modes show weak to medium intensity scattering at 1506–1509 cm−1 for MIII(TBPP)(Nc) and this is the marker Raman band of Nc•− when thus excited. The scatterings due to the Nc breathings, ring radial vibration, aza group stretchings, naphthalene stretchings, benzoisoindole stretchings and the coupling of pyrrole CC and aza CN stretchings in MIII(TBPP)(Nc) are all slightly blue shifted along with the decrease in rare earth ionic radius, confirming the effects of increased ring–ring interactions on the Raman characteristics of naphthalocyanine in the mixed ring double-deckers.

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As part of a large study investigating indoor air in residential houses in Brisbane, Australia, the purpose of this work was to quantify indoor exposure to submicrometer particles and PM2.5 for the inhabitants of 14 houses. Particle concentrations were measured simultaneously for more than 48 hours in the kitchens of all the houses by using a condensation particle counter (CPC) and a photometer (DustTrak). The occupants of the houses were asked to fill in a diary, noting the time and duration of any activity occurring throughout the house during measurement, as well as their presence or absence from home. From the time series concentration data and the information about indoor activities, exposure to the inhabitants of the houses was calculated for the entire time they spent at home as well as during indoor activities resulting in particle generation. The results show that the highest median concentration level occurred during cooking periods for both particle number concentration (47.5´103 particles cm-3) and PM2.5 concentration (13.4 mg m-3). The highest residential exposure period was the sleeping period for both particle number exposure (31%) and PM2.5 exposure (45.6%). The percentage of the average residential particle exposure level in total 24h particle exposure level was approximating 70% for both particle number and PM2.5 exposure.