乙型脑炎患者脑脊液和血浆氨基酸代谢的变化

本文采用气相色谱法对５７例乙型脑炎患者极期和２１例恢复期患者的脑脊液（ＣＳＦ）和血浆１４种游离氨基酸浓度进行分析。结果表明,乙脑极期ＣＳＦ游离氨基酸浓度除苏氨酸、丝氨酸值低于正常值外,其它氨基酸值均增高,其中谷氨酸、鸟氨酸、赖氨酸、缬氨酸、脯氨酸值上升明显（ａｌｌＰ＜０．０１）,至乙脑恢复期不同幅度下降。乙脑极期血浆游离脯氨酸、赖氨酸、苯丙氨酸、酪氨酸、鸟氨酸、谷氨酸浓度高于正常值,而其它８种氨基酸值均下降明显,至乙脑恢复期,多数氨基酸恢复至接近正常水平。实验提示,乙脑病毒能明显影响血浆和ＣＳＦ中氨基酸的含量,而二者具有代谢差异。     

Evolution of different oligomeric glycyl-tRNA synthetases

There are two oligomeric types of glycyl-tRNA synthetases (GlyRSs) in genome, the alpha2beta2 tetramer and alpha2 dimer. Here, we showed that the anticodon-binding domains (ABDs) of dimeric and tetrameric GlyRSs are non-homologous, although their catalytic central domains (CCDs) are homologous. The dimeric GlyRS_ABD is fused to the C-terminal of CCD in alpha-subunit, but the tetrameric GlyRS_ABD is to the C-terminal in beta-subunit during evolution. Generally, one species only contains one oligomeric type of GlyRS, but the both oligomeric GlyRSs with the multiple homologous domains can be observed in Magnetospirillum magnetotacticum genome, nevertheless, these homologous domains are probably from different genomes.     

Invited Review Free Radicals in Foods

During the last decade increasing attention has been given to the role of free radicals in biological oxidations. The subject has been of increasing interest to both the food scientist and the physiologist. Free radical scavengers in the form of both indigenous and added antioxidants are necessary for the successful preservation of food; free radicals are increasingly being implicated in the onset of, among others, ischaemic heart disease and for protection against these diseases it is suggested that the dietary intake of the antioxidant vitamins should be increased especially for diets high in polyunsaturated fats. ^1,2 Convenience and snack foods which absorb substantial amounts of frying oils are being increasingly consumed. Since poly-unsaturated fatty acids are particularly susceptible to oxidation by free radicals during the storage, cooking and frying of foods, the potential risk of exposure to lipid degradation products' is likely to have increased. In foods the non-enzymic and lipoxygenase catalysed oxidation of polyunsaturated fatty acids, β-carotene and vitamin A can result in the loss of essential nutrients and the development of off-flavours.     

Copper amine oxidases: Current state of knowledge

Summary A brief review on the structure nd functions of the copper-pyrroloquinoline quinone amine oxidases is presented. Data concerning the metal and organic cofactors are reported, giving special emphasis to their structural relationship with the protein molecule and mechanistic properties. Information on the functional role of these enzymes with respect to polyamine metabolism are also given.     

Cellulose-microfibril-orienting mechanisms in plant cells walls

A brief review is given of the changing views over the years, as knowledge of wall structure has developed, concerning the mechanism whereby cellulose chains may be oriented. This leads to an examination of current concepts, particularly those concerning microtubules. It is shown that none of the mechanisms suggested whereby microtubules might cause orientation of cellulose microfibrils is consistent with the known range of molecular architectures found in plant cell walls. It is further concluded that any mechanism which necessitates an indissoluble link between the plasmalemma and the cellulose-synthesising complex at the tip of a microfibril is unacceptable. A new proposal is presented in which it is speculated that both microtubules and microfibrils are oriented by a mechanism separate from both. It is shown that if two vectors are contemplated, one parallel to cell length and one at right angles, and a sensor exists on the plasmalemma surface which responds to changes in the vectors, then all known wall structures may be explained. The possible nature of the vectors and the sensor are considered.     

Lactic-acid fermentation as a low-cost means of food preservation in tropical countries

Abstract The range of traditional lactic-acid-fermented foods in tropical countries is briefly reviewed. Recent studies on the lactic acid fermentation of fish and cassava products are described. Lactic-acid-fermented fish products may offer considerable scope for the development of new food products and for the use of under-utilised fish species. Lactic-acid-fermented fish products are common in parts of Asia; methods to improve the product and shelf-life quality, to reduce microbial risks and to accelerate the process are described. This work is based on fish/salt/carbohydrate model systems. The nutritional aspects of cassava fermentation are discussed with respect to factors involved in determining residual cyanide levels; the possible anti-nutritional rôle of condensed tannins is mentioned. The increasing consumption of meat products in tropical countries emphasises the need for a preservation method that does not depend on refrigeration. The possible production of sausage ingredients preserved by lactic acid fermentation, and the associated research needs are described.     

The Polar Organization of the Growing Chara Rhizoid and the Transport of Statoliths are Actin-Dependent*

Horizontally positioned Chara rhizoids continue growth without gravitropic bending when the statoliths are removed from the apex by basipetal centrifugation. The transport of statoliths in centrifuged rhizoids is bidirectional: 50–60 % of the statoliths are re-transported on a straight course to the apex at velocities from 1 to 14 μm . min^?1 increasing towards the rhizoid tip. The centrifuged statoliths which are located closest to the nucleus are basipetally transported and caught up in the cytoplasmic streaming of the cell. Those statoliths which are located near the apical side of the nucleus are transported either apically or basally. A de-novo-formation of statoliths was not observed. After retransport to the apex some statoliths transiently sediment, a process which can induce a local inhibition of cell wall growth. The rhizoid bends again gravitropically only if a few statoliths finally sediment in the apex; the more statoliths that sediment in the apex the shorter the radius of bending becomes. The transport of statoliths is mediated by actin filaments which form a network of thin filaments in the apical and subapical zone of the rhizoid, and thicker parallel bundles in the basal zone where cytoplasmic streaming occurs. Both subpopulations of actin filaments overlap in the nucleus zone.     

Recent developments and applications of immobilized laccase

Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry.     

羟基磷灰石／聚乳酸及其共聚物复合生物材料

阐述了羟基磷灰石、聚乳酸和聚乙醇酸各自的结构性能特点;总结了两者通过复合有望得到具有良好力学性能、生物相容性、骨传导性的可降解羟基磷灰石／聚乳酸复合生物材料;最后展望了这类复合生物材料的发展方向。     

一种游仆虫棘毛基部纤维的形态及其在形态发生过程中的演化

游仆虫皮层棘毛基部纤维包括纵纤维、前纵纤维和放射纤维:额腹棘毛基部后纵纤维一般长而粗大,前纵纤维次之,放射纤维较细小;横棘毛基部前纵纤维几乎纵贯额腹横棘毛区皮层,而放射纤维较为细小;尾棘毛基部仅与一类更为细小的放射纤维相联系。不同额腹棘毛基部的同种纤维大小、形态不尽一致,各种纤维由棘毛基部区向皮层细胞质多个方向伸展,表现出极性和不对称性。并且额腹横棘毛基部纤维相互交联在一起,导致这一皮层区域形成强大的棘毛基部纤维网络。 游仆虫形态发生中,横棘毛原基向皮层裂口上方伸出一束粗大的纤毛芽时,先后发生模棘毛原基前纵纤维芽、额腹棘毛原基后纵纤维芽,以及这些棘毛原基放射纤维芽。纤维芽的发育顺序是从左列棘毛原基开始,到右侧的棘毛原基。这种纤维物质生长的顺序性,与新棘毛原基的发生和分化是相一致的。并且额腹棘毛基部后纵纤维和横棘毛基部前纵纤维形成中显示出极性和方向性,纤维物质生长伸长的方向与相应的新棘毛迁移方向相反。 老棘毛基部纤维在游仆虫形态发生过程中必然要退化。我们推测,其瓦解过程与细胞分化中老棘毛逐渐失去功能是有联系的。     

Predicting siRNA activity based on back-propagation neural network

RNA interference (RNAi) is a phenomenon of gene silence induced by a double-stranded RNA (dsRNA) homologous to a target gene.RNAi can be used to identify the function of genes or to knock down the targeted genes.In RNAi technology,19 bp double-stranded short interfering RNAs (siRNA) with characteristic 3' overhangs are usually used.The effects of siRNAs are quite varied due to the different choices in the sites of target mRNA.Moreover,there are many factors influencing siRNA activity and these factors are usually nonlinear.To find the motif features and the effect on siRNA activity,we carried out a feature extraction on some published experimental data and used these features to train a backpropagation neural network (BP NN).Then,we used the trained BP NN to predict siRNA activity.     

我国现有的金鱼品种的分类及其系统发育的探讨1)

一、引言 金鱼是我国广大人民乐于饲养的一种家养观赏鱼类。它是由野生红黄色鲫鱼演变而来的。明朝李时珍在《本草纲目》中记载:金鱼“述异记载晋桓冲游庐山,见湖中有赤鳞鱼,即此也。”他还写道:“自宋始有畜者,今则处处家养玩矣。”因此可以认为金鱼起源于我国晋朝(公元265—420年间)。至今已有一千多年的历史了。 李璞(1959)报道了我国的金鱼品种已有二十余个。徐金声等(1980)报道有143个之多。耶么迄今为止我国的金鱼品种究竟有多少呢?为了弄清我国的金鱼品种资源,作者曾在北京等十七个省市的各大公园和花木公司所属鱼场作了调查。在调查过程中,我们     

Optimized luciferase assay for cell-penetrating peptide-mediated delivery of short oligonucleotides

An improved assay for screening for the intracellular delivery efficacy of short oligonucleotides using cell-penetrating peptides is suggested. This assay is an improvement over previous assays that use luciferase reporters for cell-penetrating peptides because it has been scaled up from a 24-well format to a 96-well format and no longer relies on a luciferin reagent that has been commercially sourced. In addition, the homemade luciferin reagent is useful in multiple cell lines and in different assays that rely on altering the expression of luciferase. To establish a new protocol, the composition of the luciferin reagent was optimized for both signal strength and longevity by multiple two-factorial experiments varying the concentrations of adenosine triphosphate, luciferin, coenzyme A, and dithiothreitol. In addition, the optimal conditions with respect to cell number and time of transfection for both short interfering RNA (siRNA) and splice-correcting oligonucleotides (SCOs) are established. Optimal transfection of siRNA and SCOs was achieved using the reverse transfection method where the oligonucleotide complexes are already present in the wells before the cells are plated. Z′ scores were 0.73 for the siRNA assay and 0.71 for the SCO assay, indicating that both assays are suitable for high-throughput screening.     

Poly(dG)-poly(dC) DNA appears shorter than poly(dA)-poly(dT) and possibly adopts an A-related conformation on a mica surface under ambient conditions

Three types of DNA: approximately 2700 bp polydeoxyguanylic olydeoxycytidylic acid [poly(dG)-poly(dC)], approximately 2700 bp polydeoxyadenylic polydeoxythymidylic acid [poly(dA)-poly(dT)] and 2686 bp linear plasmid pUC19 were deposited on a mica surface and imaged by atomic force microscopy. Contour length measurements show that the average length of poly(dG)-poly(dC) is approximately 30% shorter than that of poly(dA)-poly(dT) and the plasmid. This led us to suggest that individual poly(dG)-poly(dC) molecules are immobilized on mica under ambient conditions in a form which is likely related to the A-form of DNA in contrast to poly(dA)-poly(dT) and random sequence DNA which are immobilized in a form that is related to the DNA B-form.     

Electromagnetic fields: mechanism,cell signaling,other bioprocesses,toxicity, radicals,antioxidants and beneficial effects

Electromagnetic fields (EMFs) played a role in the initiation of living systems, as well as subsequent evolution. The more recent literature on electrochemistry is documented, as well as magnetism. The large numbers of reports on interaction with living systems and the consequences are presented. An important aspect is involvement with cell signaling and resultant effects in which numerous signaling pathways participate. Much research has been devoted to the influence of man-made EMFs, e.g., from cell phones and electrical lines, on human health. The degree of seriousness is unresolved at present. The relationship of EMFs to reactive oxygen species (ROS) and oxidative stress (OS) is discussed. There is evidence that indicates a relationship involving EMFs, ROS, and OS with toxic effects. Various articles deal with the beneficial aspects of antioxidants (AOs) in countering the harmful influence from ROS-OS associated with EMFs. EMFs are useful in medicine, as indicated by healing bone fractures. Beneficial effects are recorded from electrical treatment of patients with Parkinson’s disease, depression, and cancer.     

Global Rare Earth In‐Use Stocks in NdFeB Permanent Magnets

The rare earth elements are indispensible in modern technology, especially in the applications of permanent magnets. Very little quantitative information is available on rare earth elements used in permanent magnets, however. This study looks back to 1983, when neodymium‐iron‐boron (NdFeB) permanent magnets were first manufactured, and reaches to 2007, when the market of permanent magnets was well developed. We draw on the historical data on permanent magnets from China, Japan, the United States, and Europe to provide the first estimates of global in‐use stocks for four rare earth elements—praseodymium (Pr), neodymium (Nd), terbium (Tb), and dysprosium (Dy)—in NdFeB permanent magnets. In‐use stocks amount to 62.6 gigagrams (Gg) Nd, 15.7 Gg Pr, 15.7 Gg Dy, and 3.1 Gg Tb; these stocks, if efficiently recycled, could provide a valuable supplement to geological stocks as they are almost four times the 2007 annual extraction rate of the individual elements.     

Determination of tobacco-specific N-nitrosamines in urine of smokers and non-smokers

Tobacco-specific N-nitrosamines (TSNA) include 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N′-nitrosonornicotine (NNN), N′-nitrosoanabasine (NAB) and N′-nitrosoanatabine (NAT) and are found in tobacco and tobacco smoke. TSNA are of interest for biomonitoring of tobacco-smoke exposure as they are associated with carcinogenesis. Both NNK and NNN are classified by IARC as Group 1 carcinogens. Samples of 24?h urine collections (n?=?108) were analysed from smokers and non-smokers, using a newly developed and validated LC-MS/MS method for determining total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL, the major metabolite of NNK), and total NNN, NAB and NAT. TSNA levels in smokers’ urine were significantly higher than in non-smokers. In smokers, urinary excretion of total TSNA correlated significantly (r?>?0.5) with markers of smoking dose, such as daily cigarette consumption, salivary cotinine and urinary nicotine equivalents and increased with the ISO tar yield of cigarettes smoked. The correlation between urinary total NNN and the smoking dose was weaker (r?=?0.4–0.5). In conclusion, this new method is suitable for assessing tobacco use-related exposure to NNK, NNN, NAB and NAT.     

光声成像在光动力疗法研究中的应用

组织氧合作用和光敏剂应用在疾病诊治中都有着重要的作用,因此其实时在体无损检测很有意义。光动力疗法涉及光敏剂、光和氧分子三大要素,其疗效受组织氧合作用影响。本文对光声成像(PAI)、光声寿命成像(PALI)和多光谱光声层析成像(MSOT)等光声成像技术在光动力疗法的研究和应用中的使用现状进行了综述。对相关设备系统在检测光敏剂、组织氧分压和微血管损伤等方面的应用原理和技术分别进行了介绍,并总结了这些技术的应用前景。     

人心果和蛋黄果染色体核型分析

研究了山榄科的2种优稀热带果树--人心果及蛋黄果的染色体计数及其染色体形态与核型分析.结果表明:人心果体细胞染色体2n=2X=26,核型类型为2B型,核型公式为18m+8sm,染色体相对长度组成为2L+12M:+8M1+4S,不对称系数为61.71%;蛋黄果体细胞染色体2n=2X=28,核型类型为1A型.核型公式为26m+2sm,染色体相对长度组成为2L+10M2+16M1,不对称系数为59.193%.     

三种常见实蝇的形态学、生物学和生态学比较

对瓜实蝇Bactrocera (Tetradacus) minax (Enderlein)、桔小实蝇Bactrocera (Bactrocera) dorsalis (Hendel)和桔大实蝇Bactrocera (Zeugodacus) cucurbitae (Coquillett)的形态学、生物学、生态学等方面进行了比较和分析,包括三种实蝇在国内外的分布情况,对寄主选择的差异,各种虫态的形态特征,发育历期和生活史,并对它们的危害状况和防治方法分别作了介绍,可为3种实蝇的鉴定和防治提供参考.