The continuing conundrum of the LEA proteins

Research into late embryogenesis abundant (LEA) proteins has been ongoing for more than 20 years but, although there is a strong association of LEA proteins with abiotic stress tolerance particularly dehydration and cold stress, for most of that time, their function has been entirely obscure. After their initial discovery in plant seeds, three major groups (numbered 1, 2 and 3) of LEA proteins have been described in a range of different plants and plant tissues. Homologues of groups 1 and 3 proteins have also been found in bacteria and in certain invertebrates. In this review, we present some new data, survey the biochemistry, biophysics and bioinformatics of the LEA proteins and highlight several possible functions. These include roles as antioxidants and as membrane and protein stabilisers during water stress, either by direct interaction or by acting as molecular shields. Along with other hydrophilic proteins and compatible solutes, LEA proteins might also serve as “space fillers” to prevent cellular collapse at low water activities. This multifunctional capacity of the LEA proteins is probably attributable in part to their structural plasticity, as they are largely lacking in secondary structure in the fully hydrated state, but can become more folded during water stress and/or through association with membrane surfaces. The challenge now facing researchers investigating these enigmatic proteins is to make sense of the various in vitro defined functions in the living cell: Are the LEA proteins truly multi-talented, or are they still just misunderstood?     

镉污染对莫桑比克罗非鱼血清蛋白的影响

通过分析莫桑比克罗非鱼血清蛋白含量的变化,研究镉对鱼类的致毒效应,试验结果表明,镉能升高血清总蛋白,球蛋白含量、降低白蛋白／球蛋白比值,但对血清白蛋白含量没有影响,镉对血清球蛋白各组分的影响有其特异性,对莫桑比克罗非鱼血清球蛋白成分产生作用的镉浓度阈值为０．００５ｍｇ／Ｌ,分析血清蛋白含量的变化,可以为诊断镉污染提供理论依据。     

恶臭假单胞菌好氧降解高氯联苯的蛋白质组分析

利用固相pH梯度双向凝胶电泳分离恶臭假单胞菌以葡萄糖和Aroclor1260作为营养基质生长的菌株总蛋白,凝胶经银蓝显色后,采用PDQuest图像分析软件比较、分析识别差异表达蛋白,应用MOLDI-TOF-MS得到相应的肽质量指纹图谱,然后搜索数据库鉴定部分差异蛋白点.结果表明,获得了分辨率较高、重复性较好的不同营养基质条件下菌株蛋白的双向凝胶电泳图谱,比较分析共发现80个差异蛋白点,成功鉴定14个差异表达蛋白,包括应激应答蛋白、蛋白质生物合成、运载体和代谢相关酶类.提示与葡萄糖作为生长基质相比,菌体以多氯联苯作为碳源和能源生长时,产生应激,通过增强应激响应蛋白、蛋白质生物合成相关蛋白和相关代谢酶类的表达使细胞在胁迫条件下维持自身的稳定性与生长代谢.     

Immunoblot detection of enzyme proteins of peroxisomal β-oxidation in fibroblasts,amniocytes, and chorionic villous cells. Possible marker for prenatal diagnosis of Zellweger's syndrome

The amounts of enzyme proteins of peroxisomal β-oxidation in fibroblasts and chorionic villous cells from infants with Zellweger syndrome and in fibroblasts, amniocytes, and chorionic villi from healthy controls were measured by immunoblot analysis. Immunoreactive proteins of peroxisomal acyl-CoA oxidase and 3-ketoacyl-CoA thiolase were absent in fibroblasts and chorionic villous cells from the patients, yet these enzyme proteins were present in fibroblasts, cultured amniocytes, and chorionic villi from the normal controls. These results show that immunoblot analysis of peroxisomal β-oxidation enzymes in amniocytes and chorionic villous cells is of potential value for the prenatal detection of Zellweger syndrome.     

Stability and self-organization of proteins

X-ray crystallography and NMR provide insight into the three-dimensional structure of proteins at high resolution yielding a relatively small number of stable "topologies". Their free energies of stabilization are minute compared to the total molecular energy. Molecular adaptation to extremes of physical conditions at the protein level refers to marginal alterations of the intramolecular interactions; clearcut predictions with respect to the correlation of protein structure and protein stability are at present not possible. The acquisition of the native structure of proteins is determined by the kinetically accessible minimum of potential energy. The overall mechanism may be described as a hierarchical condensation with elements of secondary/super-secondary structure and subdomains/domains as intermediate stages. In the case of oligomeric and multimeric proteins, folding and association of subunits follow a consecutive uni-bimolecular mechanism, the kinetics of which can be simulated with high precision. The "code of protein folding" is still unknown.     

Gen-Struktur und Gen-Expression

In the chicken oviduct the synthesis of the egg-white proteins ovalbumin, conalbumin, ovomucoid and lysozyme is controlled by the female sex steroids. The steroid-controlled rate of synthesis of these proteins is closely correlated to the cellular concentration of the egg-white protein mRNAs. The accumulation of these mRNAs is achieved by a drecreased rate of degradation and an increased rate of synthesis. To understand the molecular mechanism that regulates the expression of this group of genes we have isolated the lysozyme and ovomucoid gene by gene-cloning. The structure and expression of the lysozyme gene has been studied.     

基于iTRAQ技术荧蒽降解菌的比较蛋白质组学分析

提取荧蒽不同诱导时间的红球菌BAP-1蛋白,应用iTRAQ技术结合LC-MS/MS对差异蛋白进行聚类以及生物信息学分析,以研究荧蒽高效降解菌的蛋白功能调控机理.结果表明：共鉴定到796个差异蛋白（差异倍数为2）,其中表达上调的有613个,表达下调的有183个.3个比对组（3d/1d、6d/1d和8d/1d）共同差异表达蛋白为111个（上调56个,下调55个）.通过COG、GO富集和pathway富集分析后发现绝大部分差异蛋白参与代谢和能量产生过程.在荧蒽诱导下上调关键蛋白有细胞色素C、三磷酸腺苷合成酶、二磷酸核苷等激酶,还有一些结合蛋白、脱氢酶、核糖体蛋白和趋化性蛋白等;下调显著的是5-甲基四氢蝶酰三谷氨酸-同型半胱氨酸甲基转移酶.这些蛋白共同组成蛋白互作网络调控荧蒽降解菌的一系列生命活动.     

固体发酵提高水生植物发酵产物蛋白含量的研究

采用微生物固体发酵技术对伊乐藻(Elodea nuttalli)、苦草(Vallinmeria spiralis)和喜旱莲子草(Alterranthera philoxerides)3种高等水生植物进行单细胞蛋白生产的研究,分析单一菌种和混合菌种发酵过程中水生植物粗蛋白含量和纤维素酶活的变化过程.研究结果表明,与单一霉菌发酵相比,利用霉菌与酵母混合发酵,可明显提高发酵产物粗蛋白产量,其中以黑曲霉(Aspergillus niger)与产朊假丝酵母(Candida utilis)混合发酵苦草的粗蛋白含量最高,产物中粗蛋白含量最高可达39.88%,粗蛋白增加率为84.2%,使其有可能成为鱼、家禽和家畜的蛋白饲料来源.因此,利用固体发酵处理水生植物可以实现水生植物的资源化.     

Application of proteomics in environmental science

Proteomics involves the separation of proteins, identification of the amino acid sequence of the interested or target proteins, study of the function of the proteins, modification, structure and ultimate assignments to functional pathways in the cell. The proteomic investigations have contributed greatly to human diseases studies, new drugs discovery researches, and environmental science in recent years. This article provides a review on the development of the main proteomic technologies, including both the gel based and non-gel based technologies, and their applications in environmental science. Proteomic technologies have been utilized in the environmental stresses studies to analyze the induction or reduction of proteins at expression level and identify the target proteins to investigate their function in response to environmental stresses, such as high or low pH, oxidation stress, and toxic chemicals. Such protein responses are also helpful to understand the mechanisms of some cellular activities and the functions of some proteins.     

酵母提取物对葡萄糖发酵生产生物破乳菌Alcaligenes sp. S-XJ-1的影响

以从石油污染的土壤中筛选出1株生物破乳菌Alcaligenes sp.S-XJ-1为对象,考察了以葡萄糖为碳源时添加酵母提取物对生物破乳菌菌体性质、破乳性能以及菌体元素组成的影响.结果表明,酵母提取物的投加能够有效提高生物破乳菌产量,在酵母提取物浓度为5 g.L-1时,生物破乳菌产量达到3.0 g.L-1,此时葡萄糖利用率亦达到最大的58%.随着酵母提取物的投加浓度的增大,培养得到的菌体破乳性能提高,在投加浓度为10 g.L-1时,破乳率达到76%;而培养得到的菌体C/N有所降低,对其菌体表面蛋白进行提取测定发现菌体总蛋白含量升高,这与FTIR分析破乳菌菌体表面蛋白质类物质提高的结论一致.推测该生物破乳菌菌体蛋白含量的提高增强了菌体的破乳性能,菌体蛋白类物质是影响其破乳性能的关键组分之一.     

Blaues Blut: Struktur und Evolution der Hämocyanine

Hemocyanins are the oxygen-transporting proteins in arthropods and molluscs, the oxygen is bound by two copper atoms. Spectroscopic studies on the active site show similarities to the active site of a further group of copper-containing proteins, the tyrosinases. Arthropodan and molluscan hemocyanins form high-molecular aggregates which are markedly different in size and quaternary structure. There is only one tertiary structure of an arthropodan hemocyanin available, but from comparison of all amino acid sequences known so far from arthropodan hemocyanins, a common tertiary structure for all arthropodan hemocyanins can be deduced. Again, sequence comparison allows the construction of an evolutionary tree for some oxygen-binding copper proteins.     

红球菌跨膜运输荧蒽的差异膜蛋白分析

提取不同时间荧蒽诱导下红球菌BAP-1分泌的膜蛋白,利用同位素标记相对和绝对定量技术（iTRAQ技术）结合液相二级质谱对差异膜蛋白进行聚类以及生物信息学分析.旨在从蛋白质层面上研究红球菌BAP-1跨膜运输荧蒽过程中起关键作用的膜蛋白种类及其作用机制.结果共鉴定到172个差异膜蛋白.通过差异膜蛋白的COG和GO功能分析,发现荧蒽的加入主要影响了红球菌BAP-1细胞膜上与能量、转运相关的膜蛋白.ABC转运蛋白和TonB依赖转运蛋白作为微生物主要的载体蛋白对BAP-1跨膜运输荧蒽起到了重要作用.过氧化氢酶和超氧化物歧化酶在第6d有一个显著上调,作为抗氧化防御机制来保护微生物.各种膜蛋白在不同阶段发挥着各自作用,这些蛋白共同组成蛋白互作网络调控红球菌BAP-1的跨膜运输过程.     

微生物全细胞传感器在重金属生物可利用度监测中的研究进展

传统的物理化学方法主要用于测定环境重金属的总量,微生物全细胞传感器可以对土壤及水体环境的重金属生物可利用度进行监测.此外,微生物全细胞传感器还具有操作简单、快速、经济的特点,适用于污染事件的应急监测.微生物全细胞传感器的生物学元件主要由MerR、ArsR、RS等家族的金属调控蛋白和gfp、lux、luc等报告基因组成.调控蛋白、报告基因与微生物全细胞传感器的灵敏度、特异性和监测特点有关.受pH、金属螯合物及检测条件等因素的影响,不同的环境条件下的重金属生物可利用度是不同的.增加重金属在微生物细胞内的累积,进行调控蛋白的分子生物学改造,优化检测条件是提高传感器灵敏度、特异性和准确性的可行方案.实现污染物的原位和在线监测是微生物全细胞传感器的主要发展方向.     

Molekulare Zellbiologie der Hitzestreßantwort Teil I

In a physiological range of hyperthermia all living systems respond with a complex reprogramming of cellular activities to provide a basis for survival during the stress period and for a rapid restoration of normal activities in the recovery period. A prominent characteristic of the response is the induced synthesis of heat-stress proteins which is likewise evoked by numerous chemical stressors. The common signal transduction chain leading to the activation of heat-stress genes evidently involves the transient accumulation of abnormal proteins. The dominant HSPs belong to five conserved stress protein families, whose members are essential components of all living cells with general functions by far exceeding the stress response.     

Hepatologie Neuere Forschungsergebnisse in ihrer Bedeutung für das Verständnis von Leberkrankheiten

By two exemplary clinical situations — acute viral hepatitis, acute-phase reaction of the liver — the significance of basic research for the understanding of clinical phenomena and for the development of new diagnostic and therapeutic procedures is demonstrated. The very different phenomena following infection with the hepatitis-B-virus can be explained by the variation in the interactions of virus and liver cell, by the immune reaction of the host, and by mutants of the virus. The reaction of the liver to an extrahepatic infection is mediated by interleukin-6, and characterized by an alteration in protein metabolism. The synthesis of acute-phase proteins is increased. The proteins confine the local injury and establish the homeostasis of the organism.     

'Molecular farming' of antibodies in plants

'Molecular farming' is the production of valuable recombinant proteins in transgenic organisms on an agricultural scale. While plants have long been used as a source of medicinal compounds, molecular farming represents a novel source of molecular medicines, such as plasma proteins, enzymes, growth factors, vaccines and recombinant antibodies, whose medical benefits are understood at a molecular level. Until recently, the broad use of molecular medicines was limited because of the difficulty in producing these proteins outside animals or animal cell culture. The application of molecular biology and plant biotechnology in the 1990s showed that many molecular medicines or vaccines could be synthesised in plants and this technology is termed 'molecular farming'. It results in pharmaceuticals that are safer, easier to produce and less expensive than those produced in animals or microbial culture. An advantage of molecular farming lies in the ability to perform protein production on a massive scale using hectares of cultivated plants. These plants can then be harvested and transported using the agricultural infrastructure. Thus, molecular farming allows rapid progress from genetic engineering to crop production, and new cash crops producing recombinant proteins are already being commercially exploited. We speculate that as functional genomics teaches us more about the nature of disease, molecular farming will produce many of the protein therapeutics that can remedy it.     

Inducible immune proteins in the dampwood termite <Emphasis Type="Italic">Zootermopsis angusticollis</Emphasis>

Dampwood termites, Zootermopsis angusticollis (Isoptera: Termopsidae), mount an immune response to resist microbial infection. Here we report on results of a novel analysis that allowed us to electrophoretically assess changes in hemolymph proteins in the same individual before and after exposure to a pathogen. We demonstrate that contact with a sublethal concentration of the entomopathogenic fungus Metarhizium anisopliae (Deuteromycotina:Hypomycetes) induces the production of protective proteins in nymphs, pseudergates (false workers), and soldiers. Termites exposed to an immunizing dosage of fungal conidia consistently showed an enhancement of constitutive proteins (62–85 kDa) in the hemolymph as well as an induction of novel proteins (28–48 kDa) relative to preimmunization levels. No significant differences in protein banding patterns relative to baseline levels in control and naïve termites were observed. Incubating excised and eluted induced proteins produced by immunized pseudergates or immunized soldiers with conidia significantly reduced the germination of the fungus. The fungistatic effect of eluted proteins differed significantly among five colonies examined. Our results show that the upregulation of protective proteins in the hemolymph underscores the in vivo immune response we previously recorded in Z. angusticollis.     

嗜酸硫杆菌双组分信号转导系统多样性分析

为探索嗜酸硫杆菌(Acidithiobacillus)对极端矿山环境条件感知和反应分子机制的差异,利用生物信息学方法鉴定和分析了两株嗜酸氧化亚铁硫杆菌、一株喜温嗜酸硫杆菌和一株耐冷嗜酸硫杆菌的双组分信号转导系统(TCS)结构多样性特征.结果表明,4株嗜酸硫杆菌拥有27~38个TCS蛋白,聚类分析显示有16组配对的TCS族、4组孤儿组氨酸蛋白激酶(HK)和9组孤儿反应调节蛋白(RR),与其进化分支有较好的相关性;其中9个配对和5个不配对的TCS 蛋白族为嗜酸硫杆菌菌株所共有,其余特有TCS均在一个或几个菌株中缺失.嗜酸硫杆菌菌株共有的TCS功能涉及氮素固定及代谢调节、柠檬酸/苹果酸代谢调节等,特有TCS功能涉及如趋化性调控、重金属响应、铜抗性调控等,这可能有助于菌株在极端矿山环境中生存.