果树组织中总RNA提取的新方法

本研究设计了一种新的RNA提取方法 ,解决了RNA提取时容易被降解和污染这一关键问题。通过加入Rnase抑制剂 ,消除了同外源RNase对RNA的降解 ,结合DNA难呈低盐溶液(140mmol·L -1NaCl)的原理 ,去除了DNA对RNA提取液的污染 ;先后使用酚和氯仿 ,有效地去除了蛋白质和酚类物的污染 ,利用抗氧化剂PVP和巯基乙醇 ,消除了内源酚类物质氧化变色对病毒RNA逆转录的影响。采用上述方法可以在4～5h内得到纯度高、含量大、完整性好的果树总RNA ,并获得了逆转录活性较强的病毒RNA ,同时使提取RNA的成本降低。这些方法对苹果、葡萄、桃、樱桃等果树总RNA的提取均适用。

Collisional quantum interference effect on rotational energy transfer in an atom-diatom system

The theoretical model of collisional quantum interference (CQI) in intramolecular rotational energy transfer is described in an atom-diatom system, based on the first Born approximation of time-dependent perturbation theory and considering a long-range interaction potential. The relation between differential and integral interference angles is obtained. For the CO A(1)Pi (v = 0)/e(3)Sigma (-)(v = 1)-He collision system, the calculated integral interference angles are consistent with the experimental values. The physical significance of interference angle and the essential factors it depends on as well as the influence of the short-range interaction on CQI are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

Multipolar model for collisional quantum interference on rotational energy transfer

A theoretical model of collisional quantum interference (CQI) is developed in a diatom-diatom system based on the first-order Born approximation of time-dependent perturbation theory and the multipolar interaction potential. The transition cross section is obtained. The relations between the differential and integral interference angles are discussed. The key factors on the determination of the differential and integral interference angles are obtained. The changing tendency of the interference angles with the experimental temperatures is obtained.

Interference effects in the extraction of trace metals from estuarine waters

We have found that a commonly used complexation and solvent extraction technique (using mixed dithiocarbamates/Freon/HNO3) does not always extract Cd, Co, Cu and Ni from estuarine samples with the same efficiency as from Milli-Q water. For samples collected from the Derwent Estuary (Australia), the reduced extraction efficiency only occurred for unfiltered samples, but low extraction efficiencies were also observed for a (filtered) riverine certified reference material (SLRS-3) suggesting that the effect may be widespread. We have not been able to identify the reason for the low extraction efficiency and, although it is strongly correlated with the presence of high concentrations of suspended solids, dissolved organic matter and particulate iron, we have no experimental evidence to directly link any of these parameters to the effect. It is possible that similar effects may occur in other techniques which rely on a preconcentration step prior to analysis and that some literature values of heavy metals in estuarine waters may be low. We propose a modification of the standard complexation/solvent extraction method which overcomes these difficulties without adding significantly to the time taken for analyses.

土壤中Frankia菌RNA提取

土壤中Ｆｒａｎｋｉａ菌ＲＮＡ提取王育英，林建群，郭秀荣，李彤，张忠泽（中国科学院沈阳应用生态研究所，１１００１５）Ｆｒａｎｋｉａ非亚科共生固氮是一类重要的固氮资源。对Ｆｒａｎｋｉａ共生生物学、生态学等特性曾进行过广泛的研究。８ｔ０年代末，Ｆｒａｎｋｉ...

Self-assembly of single-stranded RNA on carbon nanotube: Polyadenylic acid to form a duplex structure

All messenger-RNA (mRNA) molecules in eukaryotic cells have a polyadenylic acid [poly (rA)] tail at the 3'-end and human poly (rA) polymerase (PAP) has been considered as a tumor-specific target. A ligand that is capable of recognizing and binding to the poly(M) tail of mRNA might interfere with the full processing of mRNA by PAP and can be a potential therapeutic agent. We report here for the first time that single-walled carbon nanotubes (SWNTs) can cause single-stranded poly (M) to self-structure and form a duplex structure, which is studied by UV melting, atomic force microscopy, circular dichroism spectroscopy, and NMR spectrometry.

Factor analysis used to peak position optimization and spectral interference correction in inductively coupled plasma atomic emission spectrometry

Target transformation factor analysis was used to correct spectral interference in inductively coupled plasma atomic emission spectrometry (ICP-BES) for the determination of rare earth impurities in high purity thulium oxide. Data matrix was constructed with pure and mixture vectors and background vector. A method based on an error evaluation function was proposed to optimize the peak position, so the influence of the peak position shift in spectral scans on the determination was eliminated or reduced. Satisfactory results were obtained using factor analysis and the proposed peak position optimization method.

APPLICATION OF FACTOR-ANALYSIS TO CORRECTION OF SPECTRAL OVERLAP INTERFERENCE IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

Correction of spectral overlap interference in inductively coupled plasma atomic emission spectrometry by factor analysis is attempted. For the spectral overlap of two known lines, a data matrix can be composed from one or two pure spectra and a spectrum of the mixture. The data matrix is decomposed into a spectra matrix and a concentration matrix by target transformation factor analysis. The component concentration of interest in a binary mixture is obtained from the concentration matrix and interference from the other component is eliminated. This method is applied to correcting spectral interference of yttrium on the determination of copper and aluminium: satisfactory results are obtained. This method may also be applied to correcting spectral overlap interference for more than two lines. Like other methods of correcting spectral interferences, factor analysis can only be used for additive spectral overlap. Results obtained from measurements on copper/yttrium mixtures with different white noise added show that random errors in measurement data do not significantly affect the results of the correction method.

Changes in RNA, DNA, protein contents and growth of turbot Scophthalmus maximus larvae and juveniles

The growth potential of turbot Scophthalmus maximus larvae and juveniles was studied using nucleic acid-based indices and protein variables. The experiment was carried out from 4 to 60 days post hatching (dph). A significant increase in instantaneous growth rate during metamorphosis and retarded growth rate during post-metamorphic phase were observed. Ontogenetic patterns of DNA, RNA and protein all showed developmental stage-specific traits. The RNA:DNA ratio decreased up to 12 dph, then increased rapidly till 19 dph and fluctuated until 35 dph followed by a decline to the end. The RNA:DNA ratio was positively correlated with growth rate of juveniles during the post-metamorphic phase, whereas this ratio was not a sensitive indicator of growth during the pre-metamorphic phase and metamorphosis. The protein:DNA ratio showed a similar tendency to the RNA:DNA ratio. Changes of DNA content and protein:DNA ratio revealed that growth of S. maximus performed mainly by hyperplasia from 4 to 12 dph and hypertrophy until 21 dph during the pre-metamorphic larval phase. Growth was dominantly hypertrophical from the early- to mid-metamorphosing phase and hyperplastic thereafter. The results show that the DNA content and protein:DNA ratio can evaluate growth rates of larval and juvenile S. maximus on a cellular level.

Improved RNA isolation from Laminaria japonica Aresch (Laminariaceae, Phaeophyta)

RNA isolation is difficult in some plants and algae because phenolics, polysaccharides, or other compounds can bind or co-precipitate with RNA, and because the success of RNA isolation can be strain-specific and species-specific. To create an improved RNA isolation protocol for Laminaria japonica Aresch (Laminariaceae, Phaeophyta), four methods for extracting RNA were tested. A cetyltrimethylammonium bromide (CTAB)-based RNA extraction protocol was developed that clearly showed 28S and 18S ribosomal RNA bands and produced RNA with high yield (68 mu g g(-1) fresh weight) and high quality (A (260/280) ratio 1.96 +/- 0.05). The isolated RNA was intact, and RT-PCR analysis confirmed that further molecular application is feasible.

Identification of peptides that bind with thymidylate synthase RNA using mRNA display technique

Using in vitro selection method to isolate nucleic acids, peptides and proteins has been studied intensively in recent years. In vitro mRNA display is a new and effective technique for peptides selection, and the rationale of this technique is that a synthetic mRNA with puromycin could covalently link with the protein that it encodes, thus an mRNA-protein fusion is formed. This approach has been used in identification of many functional peptides. The peptides binding with thymidylate synthase RNA were isolated using mRNA display technique from a large peptide library (>10(13) different sequences). The selection scheme was constructed, and the experimental conditions, including library synthesis, formation of RNA-peptide fusion and RNA immobilization were optimized. Eight cycles have been processed and the results confirmed that the selected peptides could bind with thymidylate synthase mRNA specifically. Compared the amino acid sequences of the selected peptides with those from the initial random library, the basic and aromatic residues in selected peptides were enriched significantly, suggesting these peptide regions may be important in the peptide-TS mRNA interaction. As a novel in vitro selection approach, mRNA display technique would be developed as a powerful tool for isolation of functional peptides and proteins that could interact with immobilized targets with high affinity and specificity.