涡鞭毛虫(甲藻)着丝粒/动粒蛋白的检索

用ACA血清作荧光观察, 隐沟虫细胞动粒蛋白表明, 隐沟虫的这些蛋白虽结合在核骨架上, 但在间期时并不形成点状的前着丝粒。免疫印迹检查表明隐沟虫和尖尾虫的着丝粒蛋白B彼此一致, 而且与四膜虫和眼虫也高度一致。但用ACA血清作免疫印迹检查时, 尖尾虫的蛋白虽与四膜虫和眼虫的相近, 与隐沟虫的却有极大的差异。以抗动粒蛋白的单抗作此种检查时, 尖尾虫与眼虫的反应带相同, 而隐沟虫则与源真核生物(Archezoa)贾第虫(Giardia lamblia)的相同; 而且隐沟虫和贾第虫都与几种原细菌有两条相同的反应带。

嗜热四膜虫的着丝粒蛋白检查

目前国际上的着丝粒蛋白研究工作几乎全是以酵母和高等生物为材料进行的. 为了从起源与进化的角度考察着丝粒蛋白, 作者以人喉癌培养细胞 Hep Ⅱ作为对照材料, 以两种 ACA 血清和 CENP-B 单抗、多抗以及 CHO 动粒蛋白单抗为探针, 用间接免疫荧光和免疫印迹技术对嗜热四膜虫(Tetrahymena thermophila)作检查. 免疫荧光结果表明, Hep Ⅱ细胞的着丝粒抗原在间期核中呈点状分布: 与 HepⅡ 细胞的不同, 嗜热四膜虫的着丝粒抗原在问期核中的分布呈不规则的斑块状。

小眼虫的着丝粒蛋白检查

为了从起源与进化的角度考察着丝粒蛋白, 作者从比酵母更低等的原生生物着手, 检查它们的着丝粒蛋白. 另文作者已报道了对四膜虫研究的结果, 该文报道的是对小眼虫(Englena gracilis) 检查. 作者的结果表明: 眼虫细胞核里存在的 ACA 抗原的分子量, 包括了用 ACA 血清在高等生物中检出来的 CENP-A、CENP-B、CENP-C 和 CENP-C 这几类基本的着丝粒蛋白组分. 作免疫荧光染色后, 细胞核呈很强的阳性反应, 但分辨不出前着丝粒小点. 核仁不被荧光染色, 除了核仁外似乎整个核都被染色. 这可能反映了抗原的分布在核内不是集中成点状的. 经过制备核骨架的程序处理后, 细胞核仍为阳性(尽管荧光较弱). 如此看来, 眼虫至少已有相当大一部分的 ACA 抗原是与核骨架结合着的. 对分离的细胞核作相应的抽提处理后再作免疫印迹检查, 得到的阳性反应带也证明了这一点。

乙丙共物聚的结晶速率与序列结构

本文用(体)热膨胀计法研究了共聚物组成、催化体系对乙丙共聚物结晶速率的影响。结果表明,同一催化体系乙丙共聚物的最大结晶速率(1/t_((1/2)(max)))随共聚物中乙烯含量的增加而增大。不同催化体系对二元乙丙共聚物的1/t_((1/2)(max))次序为:VOCl_3~->V_(5-9~-)>V_((aca?)3~-)。加入活化剂ETCA的各催化体系的二元乙丙共聚物的1/t_((1/2)(max))为VOCl_3~-ETCA>V_(5-9~-)ETCA>V_((ocac)~-)ETCA。结合结晶度、T_g、以及不同序列分布共聚物组成的测定,可推测VOCl_3~-体系乙丙共聚物具有较长的聚乙烯序列结构,V_(5-9~-)体系次之,V_((acac)_3~-)体系的乙丙共聚物分子链有更多的无规结构。

Geochemieal records of phosphorus in Jiaozhou Bay sediments - Implications for environmental changes in recent hundred years

Phosphorus is a key element and plays an important role in global biogeochemical cycles. The evolution of sedimentary environment is also influenced by phosphorus concentrations and fractions as well as phosphate sorption characteristics of the marine sediments. The geochemical characteristics of phosphorus and their environmental records were presented in Jiaozhou Bay sediments. Profiles of different forms of phosphorus were measured as well as the roles and vertical distributions of phosphorus forms in response to sedimentary environment changes were investigated. The results showed that inorganic phosphorus ( IP) was the major fraction of total phosphorus ( TP); phosphorus which is bound to calcium, iron and occluded phosphorus, as well as the exchangeable phosphorus were the main forms of IP, especially calcium-phosphorus, including detrital carbonate-bound phosphorus ( Det - P) and authigenic apatite-bound phosphorus ( ACa - P), are the uppermost constituent of IP in Jiaozhou Bay sediments. Moreover, the lead-210 chronology technology was employed to estimate how much phosphorus was buried ultimately in sediments. And the research showed that the impacts of human activities have increased remarkably in recent years especially between the 1980s and 2000. According to research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages; (I) before the 1980s characterized by the relatively low sedimentation rate, weak land-derived phosphorus inputs and low anthropogenic impacts; (2) from the 1980s to around 2000, accelerating in the 1990s, during which high sedimentation rates, high phosphorus abundance and burial fluxes due to the severe: human activities impacted on the whole environmental system; (3) after 2000, the period of the improvement of environment, the whole system has been improved including the decreasing sedimentation rates, concentration and the burial fluxes of phosphonas.

Insight into permeability of protein through microcapsule membranes

The objective of this paper is to analyze the characteristics of protein permeability in alainate-polylysine-alginate (APA) and alginate-chitosan-alginate (ACA) microcapsules by mathematical models based on the balance of chemical potential. The comparison between calculated results and experimental data shows that the models can describe the process of protein diffusion from microcapsule and protein release into microcapsule successfully. The influences of membrane composition on the permeability of ACA microcapsule have been investigated and analyzed. The effect of resistance on the mass transfer is further analyzed theoretically with the aid of mathematical modeling. (c) 2005 Elsevier B.V. All rights reserved.

Local examination of skin diffusion using FTIR spectroscopic imaging and multivariate target factor analysis

In the context of trans-dermal drug delivery it is very important to have mechanistic insight into the barrier function of the skin's stratum corneum and the diffusion mechanisms of topically applied drugs. Currently spectroscopic imaging techniques are evolving which enable a spatial examination of various types of samples in a dynamic way. ATR-FTIR imaging opens up the possibility to monitor spatial diffusion profiles across the stratum corneum of a skin sample. Multivariate data analyses methods based on factor analysis are able to provide insight into the large amount of spectroscopically complex and highly overlapping signals generated. Multivariate target factor analysis was used for spectral resolution and local diffusion profiles with time through stratum corneum. A model drug, 4-cyanophenol in polyethylene glycol 600 and water was studied. Results indicate that the average diffusion profiles between spatially different locations show similar profiles despite the heterogeneous nature of the biological sample and the challenging experimental set-up.

Quantification of oxygenated volatile organic compounds in seawater by membrane inlet-proton transfer reaction/mass spectrometry

The role of the ocean in the cycling of oxygenated volatile organic compounds (OVOCs) remains largely unanswered due to a paucity of datasets. We describe the method development of a membrane inlet-proton transfer reaction/mass spectrometer (MI-PTR/MS) as an efficient method of analysing methanol, acetaldehyde and acetone in seawater. Validation of the technique with water standards shows that the optimised responses are linear and reproducible. Limits of detection are 27 nM for methanol, 0.7 nM for acetaldehyde and 0.3 nM for acetone. Acetone and acetaldehyde concentrations generated by MI-PTR/MS are compared to a second, independent method based on purge and trap-gas chromatography/flame ionisation detection (P&T-GC/FID) and show excellent agreement. Chromatographic separation of isomeric species acetone and propanal permits correction to mass 59 signal generated by the PTR/MS and overcomes a known uncertainty in reporting acetone concentrations via mass spectrometry. A third bioassay technique using radiolabelled acetone further supported the result generated by this method. We present the development and optimisation of the MI-PTR/MS technique as a reliable and convenient tool for analysing seawater samples for these trace gases. We compare this method with other analytical techniques and discuss its potential use in improving the current understanding of the cycling of oceanic OVOCs.

Iron organic speciation determination in rainwater using cathodic stripping voltammetry

A sensitive method using Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-ACSV) has been developed to determine for the first time iron (Fe) organic speciation in rainwater over the typical natural range of pH. We have adapted techniques previously developed in other natural waters to rainwater samples, using the competing ligand 1-nitroso-2-naphthol (NN). The blank was equal to 0.17 ± 0.05 nM (n = 14) and the detection limit (DL) for labile Fe was 0.15 nM which is 10–70 times lower than that of previously published methods. The conditional stability constant for NN under rainwater conditions was calibrated over the pH range 5.52–6.20 through competition with ethylenediaminetetraacetic acid (EDTA). The calculated value of the logarithm of β′Fe3+3(NN)β′Fe3+(NN)3 increased linearly with increasing pH according to log β′Fe3+3(NN)=2.4±0.6×pH+11.9±3.5log β′Fe3+(NN)3=2.4±0.6×pH+11.9±3.5 (salinity = 2.9, T = 20 °C). The validation of the method was carried out using desferrioxamine mesylate B (DFOB) as a natural model ligand for Fe. Adequate detection windows were defined to detect this class of ligands in rainwater with 40 μM of NN from pH 5.52 to 6.20. The concentration of Fe-complexing natural ligands was determined for the first time in three unfiltered and one filtered rainwater samples. Organic Fe-complexing ligand concentrations varied from 104.2 ± 4.1 nM equivalent of Fe(III) to 336.2 ± 19.0 nM equivalent of Fe(III) and the logarithm of the conditional stability constants, with respect to Fe3+, varied from 21.1 ± 0.2 to 22.8 ± 0.3. This method will provide important data for improving our understanding of the role of wet deposition in the biogeochemical cycling of iron.