Acetylcholinesterase and butyrylcholinesterase inhibitory activity of Pinus species essential oils and their constituents

This study aimed to investigate the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity of the essential oils from Pinus nigra subsp. nigra, P. nigra var. calabrica, and P. heldreichii subsp. leucodermis. This activity is relevant to the treatment of Alzheimer’s disease (AD), since cholinesterase drugs are currently the only drugs available to treat AD. P. heldreichii subsp. leucodermis exhibited the most promising activity, with IC₅₀ values of 51.1 and 80.6?μg/mL against AChE and BChE, respectively. An interesting activity against AChE was also observed with P. nigra subsp. nigra essential oil, with an IC₅₀ value of 94.4?μg/mL. Essential oils were analyzed by GC and GC-MS with the purpose of investigating their relationships with the observed activities. Among the identified constituents, terpinolene, β-phellandrene, linalyl acetate, trans-caryophyllene, and terpinen-4-ol were tested. trans-Caryophyllene and terpinen-4-ol inhibited BChE with IC₅₀ values of 78.6 and 107.6?μg/mL, respectively. β-Phellandrene was selective against AChE (IC₅₀ value of 120.2?μg/mL).     

Effects of initial inoculation density of Paenibacillus polymyxa on colony formation and starch‐hydrolytic activity in relation to root rot in ginseng

Aims: To examine the relationships between population growth and biological characters of the plant‐growth‐promoting rhizobacterium Paenibacillus polymyxa GBR‐1. Methods and Results: Population growth, colony formation, starch‐hydrolytic activity, and ginseng root rot caused by P. polymyxa GBR‐1 isolated from a rotten ginseng root were examined in vitro and in vivo at high [1 × 10⁸ colony‐forming units (CFU) ml^?1] and low (1 × 10⁶ CFU ml^?1) initial inoculum densities. Paenibacillus polymyxa GBR‐1 showed strong starch‐hydrolytic activity on modified starch agar with relatively low starch content, but only at certain incubation temperatures (18 and 23°C); the high‐density inoculum produced bacterial colonies about nine times thicker than those formed from the lower inoculum density. Light, scanning electron, and transmission electron microscopy showed that the thick colonies from the high‐density inoculum were filled with extracellular polymeric substances (EPS), in which a relatively small number of ovoid‐rod‐shaped bacterial cells (mostly endospore‐bearing cells) were distributed. In contrast, the thin colonies from the low‐density inoculum were composed of massive vegetative cells with a rectangular rod shape and minimum EPS. Fluorescent in situ hybridization (FISH) revealed that the β‐amylase gene was expressed only in bacterial cells from the thick colonies formed from the high‐density inoculum, but not in those from the low‐density inoculum. The culture filtrate from the thick colonies produced a hydrolytic clear zone on modified starch agar, degraded starch granules in various manners, and produced rot symptoms on ginseng root tissues. Conclusions: The biological properties of colony formation, starch hydrolysis, and ginseng tissue rotting by P. polymyxa GBR‐1 are interrelated; they are influenced by the initial bacterial population density but not by the in situ and the final population densities. Significance and Impact of the Study: Knowledge of disease‐inducing characters of P. polymyxa GBR‐1 can be used in the development of biocontrol strategies.     

Analysis of the probability of multiple taxa in a combined sample of swartkrans and kromdraai dental material

It has been argued (Grine, [1988] Evolutionary History of the “Robust” Australopithecines [New York. Aldine de Gruyter], pp. 223–243) that the australopithecine material from Swartkrans and Kromdraai represents distinct species. In an attempt to test the validity of separate taxa at Swartkrans and Kromdraai, Cope's (Cope [1989] Systematic Variation in Cercopithecus Dental Samples [Austin: University of Texas]) method of analysis was adapted and utilized. This procedure includes an analysis of the coefficients of variation (CVs) of the individual posterior teeth (buccal-lingual breadth) of a combined fossil sample compared with the CVs of several known single taxon reference groups. The Cope and Lacy (Cope and Lacy [1992] Am. J. Phys. Anthropol. 89:359–378) simulation technique was also employed in the analysis. Based on these analyses, there is no justification for a taxonomic separation between the australopithecine material from Swartkrans and Kromdraai. Therefore, the assertion that the Swartkrans and Kromdraai material represent two distinct species is not indicated by the available dental metric evidence. © 1996 Wiley-Liss, Inc.     

Recombinant Fusion Proteins for the Industrial Production of Disulfide Bridge Containing Peptides: Purification, Oxidation without Concatamer Formation, and Selective Cleavage

We report the biotechnical production of peptides of approximately 35–50 amino acids in length containing one intramolecular disulfide bridge, using a recombinant fusion tail approach. This method fills the technological gap when either (a) chemical synthesis fails due to known problematic peptide sequences or (b) if simple recombinant expression is unsuccessful due to degradation. The fusion tail described here serves several purposes: (i) it enables high expression levels inEscherichia colito be achieved; (ii) it renders the fusion protein fairly soluble; (iii) it contains a histidine affinity tag for easy purification on Ni-chelate resins, which also serves as a catalyst for the oxygen-dependent formation of the disulfide bridge; and (iv) it suppresses the formation of concatamers during the oxidation process through steric hindrance. The purified fusion protein is then immobilized on a reversed phase column for two purposes: (i) chemical cleavage of the fusion tail by cyanogen bromide and (ii) subsequent purification of the peptide. A very hydrophilic fusion partner is required so that immobilization on the reversed phase column always occurs due to the peptide. Sensitive hydrophobic residues are thereby protected from the cleavage reagent while the cleaved hydrophilic fusion tail is easily separated from the hydrophobic peptide. The method is exemplified by eight peptides representing an immunodominant epitope of the human immunodeficiency virus, but may be useful for a significant variety of similar peptides.     

Immunological comparison of native and recombinant egg allergen, ovalbumin, expressed in Escherichia coli

Chicken ovalbumin is one of the major egg white allergens which causes IgE-mediated food hypersensitivity. A gene encoding for chicken ovalbumin (Gad dI) was isolated from chicken oviduct by PCR amplification and was cloned under the control of T5 promoter fused with a six-histidine tag at the N-terminal end. Escherichia coli harbouring this construct expressed high quantities of the recombinant protein in the form of soluble fraction. The protein was purified using affinity chromatography on a Ni(2+)-nitrilotriacetic acid agarose column and was further purified to homogeneity by ion exchange chromatography. Homogeneity was confirmed through SDS-PAGE, Western blot and secondary conformation analysis. The reactivity of the recombinant and native protein was tested against six egg allergic human patient's sera and the IgE and IgG binding activity was tested using both Western blot and ELISA. When compared to native ovalbumin, the recombinant protein had similar binding activity in immunoblotting, but slightly increased activity by ELISA. Circular dichroism revealed that the recombinant protein had a slightly less compact structure than the native form. Both antigens exhibited a similar immunogenicity in mice.     

Implications of variation in resin composition among organs, tissues and populations in the tropical legume Hymenaea

Variation in leaf blade, petiole and primary stem resins, composed of sesquiterpene hydrocarbons, is analysed in two contrasting species of the tropical legume Hymenaea. Five populations of the New World H. courbaril, spanning a wide range of ecosystems, are compared with a population of the disjunct African H. verrucosa. Resins in petiole and primary stem tissue are similar, but differ significantly in total composition from leaf blade tissues. The major components, caryophyllene, - and β-selinene and β-copaene vary most significantly among the tissues, but all compounds vary at highly significant levels among populations. The variation patterns in resin composition among the leaf blade and petiole/primary stem tissues are put into a larger context of comparison with the primarily diterpenoid patterns in secondary stem and pod tissues. Although the comparatively minor quantitative differences in the sesquiterpene systems could be attributed solely to developmental and physiological differences among the tissues and populations, the total weight of accumulating evidence regarding quantitative variation and demonstrated toxic and deterrent properties of sesquiterpene resins to insect herbivores leads us to hypothesize a possible role of differential predator pressures.     

Growth regulation, plastid differentiation and the development of a photosynthetic system in cultured carrot root explants as influenced by exogenous sucrose and various phytohormones

Chromoplasts, which exist in the cells of freshly isolated carrot root explants, seemed to be transformed in thylakoid containing plastids, and chlorophyll formation was initiated if the explants were cultured in a liquid medium containing inositol and IAA as a hormonal supplement. This process was intensified when kinetin was also added, but no dependence on a sucrose supply could be found.A sucrose supply of 2% in conjunction with the combination of all three hormones, however, was needed to achieve maximal thylakoid formation including stacking in individual chloroplasts and for the very extensive chloroplast multiplication in explants growing with high cell division activity. It should be noted that the number of plastids per cell is strongly increased by the sucrose supplement which leads also to starch accumulation. However, no transformation into chloroplasts occurred without the hormonal stimulus.     

Spatial, seasonal and species variations of harmful algal blooms in the South Yellow Sea and East China Sea

The occurrences of harmful algal blooms (HABs), in terms of frequency and area in the Chinese coastal waters, have been increasing since 1980s and caused considerable economic losses. In the present study, we have analyzed spatial and seasonal characteristics of HAB events in the southern Yellow Sea and East China Sea along Chinese coast from 1933 to 2004. With a total 435 HAB records, the most frequent HAB occurrence area (FHA) is off the Yangtze River mouth and another two FHA areas are located south of the Yangtze River estuary along about isobaths of 30–60 m coastal water in the East China Sea. The time of HAB occurrence shifted during our study period: from autumn (August–October) before 1980s to July–August in 1980s, during May–July in 1990s, and May–June for the period of 2000–2004. Causative species were found to be different: Noctiluca scintillans and Skeletonema costatum were dominant causative species prior to 2000; and Prorocentrum donghaiense Lu was dominant from 2000 to 2004 and also caused large blooms in May. Trichodesmium sp. caused many HABs in autumn (August–October) prior to 1980s with only one HAB between 1980 and 2004. The changes of the dominant HAB species may have affected the timings of HAB occurrence, as well as the increasing HAB-affected areas in recent years.     

改良带蒂胸大肌肌皮瓣修复口腔颌面肿瘤术后缺损的临床分析

目的:探讨只带血管蒂的改良胸大肌皮瓣转移修复口腔颌面部组织缺损的临床效果。方法:取胸大肌皮瓣时蒂部只保留血管,利用改良只带血管蒂的胸大肌皮瓣对6例不同口腔颌面部组织缺损进行修复,包括舌癌3例、舌咽癌1例、牙龈癌1例、颊癌1例。结果:术后皮瓣血供良好,完整成活,成活率100%;所有患者获得3~18个月随访,在随访期内均存活;重建的舌外形良好,虽然味觉功能无法恢复,运动功能随切除范围增加而降低,但均能满足发音、吞咽和咀嚼功能需要。结论:只带血管蒂的改良胸大肌皮瓣是修复口腔颌面部组织缺损有效而可靠的方法,为恶性肿瘤根治术后造成的缺损提供了有力修复保障。     

Sucrose Synthetase of Rice Grains and Potato Tubers

ABSTRACT

Human coagulation factor XII, the initiating factor in the intrinsic coagulation pathway, is critical for pathological thrombosis but not for hemostasis. Pharmacologic inhibition of factor XII is an attractive alternative in providing protection from pathologic thrombus formation while minimizing hemorrhagic risk. Large quantity of recombinant active factor XII is required for screening inhibitors and further research. In the present study, we designed and expressed the recombinant serine protease domain of factor XII in Pichia pastoris strain X-33, which is a eukaryotic expression model organism with low cost. The purification protocol was simplified and the protein yield was high (~20 mg/L medium). The purified serine protease domain of factor XII behaved homogeneously as a monomer, exhibited comparable activity with the human βFXIIa, and accelerated clot formation in human plasma. This study provides the groundwork for factor XII inhibitors screening and further research.     

Ultrastructure and development during meiosis and the tetrad period of sporogenesis in the leptosporangiate fern Alsophila setosa (Cyatheaceae) compared with corresponding stages in Psilotum nudum (Psilotaceae)

The pre-meiotic, meiotic and tetrad stages of development in microsporangia of Alsophila setosa were studied with particular emphasis on the early establishment of patterning in the microspore wall and the subsequent development of the sporoderm. The data obtained were compared with corresponding ontogenetic stages of Psilotum nudum. Tapetal behaviour was also examined. During the tetrad period, only one layer, a thin undulating sheet, appeared alongside the plasma membrane of the tetraspores, and this was evidently formed on a pre-patterned structure – a fibrillar layer, corresponding to a kind of primexine matrix. The early free microspores had a wavy plasma membrane with a parallel, sinusoidal, thin initial sporoderm layer. The proximal apertural fold was observed to be an extended outgrowth of this initial spore envelope. Sporoderm ontogeny during the tetrad period in Alsophila and Psilotum show some common points, but also fundamental differences, mainly in the relative timing of events: in Alsophila the end of the tetrad period is the starting point for exospore development, whereas in Psilotum the exospore is already complete at this stage. Considerable differences were also observed in the tapetum of the two species.     

Biological components of Sites of Special Scientific Interest in Wales

The designation of Sites of Special Scientific Interest (SSSIs) is one of the major statutory measures for wildlife protection in Britain. In this account, procedures for selecting SSSIs are outlined, and the representation of habitats and species in different taxonomic groups which qualify 731 SSSIs notified in Wales (in November 1994) are summarized. Biological SSSIs occupy approximately 9.6% of the total area of Wales. There are significant differences in the numbers and sizes of sites characteristic in the uplands (few large), lowlands (many small) and coast (intermediate). Over 70% of the biological SSSIs have more than one qualifying feature. Most sites (663, 90%) have been selected for one or more habitats, and many sites (328, 45%) have particular species attributes. In relation to their total extent in Wales, some habitats (including ombrotrophic peatland, dwarf-shrub heathland, rich fen and sand dune) have greater proportional representation in SSSIs than others (such as upland grassland, woodland and scrub). These differences reflect conservation priorities for Welsh habitats which are related to the wider British context. As expected, birds and vascular plants contribute to notification of a greater number of sites than other groups; invertebrates, lichens and bryophytes qualify in some sites and require further evaluation in others; except for bats, mammals are comparatively poorly represented as special features. Birds qualify many of the largest SSSIs in Wales (breeding assemblages in the uplands and overwintering wildfowl and waders in estuaries). Possibilities for future refinement of the SSSI series are considered. It is suggested that the establishment of conservation sites is sufficiently advanced in Britain to permit worthwhile examination of the composition and function of the network as a whole against conservation objectives.     

Dynamics of antibody nuclease activity in blood of women during pregnancy and lactation

In human milk we previously found catalytic antibodies (abzymes) catalyzing hydrolysis of DNA, RNA, NMP, NDP, and NTP and also phosphorylation of proteins and lipids. In the present study we have analyzed nuclease activities of antibodies in blood of women during pregnancy and lactation. Blood of healthy male and female volunteers lacked catalytically active antibodies, whereas antibodies from blood of pregnant women hydrolyzed DNA and RNA and their relative activity varied over a wide range. Relative blood abzyme activities significantly increased after delivery and at the beginning of lactation. The highest abzyme activity was observed in blood of parturient women. Although the dynamics of changes in antibody DNase activity during pregnancy was rather individual for each woman, there was a common trend in the increase in antibody activity in the first and/or third trimester of the pregnancy. The DNase activity of IgG and IgM from blood of healthy pregnant women was 4-5 times less than that from pregnant women with pronounced autoimmune thyroiditis.     

Additional fossil Theropithecus from Hopefield, South Africa: a comparison with other African sites and a reevaluation of its taxonomic status

Additional fossil Theropithecus remains, recovered from mid to late Pleistocene deposits near Hopefield , South Africa, include portions of the jaws of at least five individuals. Extensive comparisons with fossil Theropithecus from other African sites, including Makapan , Swartkrans , Kanjera , Olorgesailie , and Olduvai , reveal few morphological differences, especially when variation in modern gelada baboons ( Theropithecus gelada ) and savannah baboons (Papio) is considered. The most pronounced differences between fossil forms are overall size and relative P3 length. However, these traits do not separate the fossil forms either chronologically or geographically. Other traits, such as depth of the fossa of the mandibular corpus, slope of the upper symphyseal shelf, and variation in the depth of the mandibular corpus, do not distinguish alleged primitive forms ( Makapan and lower beds at Olduvai ) from remains found at Hopefield , Swartkrans , Kanjera , Olorgesailie , Olduvai Bed IV, or the lower Ndutu Beds. Other traits, such as canine crown height and incisor size, are poorly documented for fossil Theropithecus . Thus, the available evidence suggests that Theropithecus darti and its successional species, T. oswaldi , can best be considered as a single fossil species, T. oswaldi , of which the remains from Hopefield are a late representative. Furthermore, lack of morphological differences dictates that Hopefield Theropithecus not be considered a distinct subspecies. Variation within the Hopefield sample shows that only one taxa is found at this site. Hypothesized physical and climatic conditions at Hopefield during the Pleistocene suggest that T. oswaldi lived near vleis or fresh water lagoons. Comparisons with modern T. gelada suggest a graminivorous diet for the fossil form.     

Genetic variation in clonal traits of Trifolium repens and species interactions

Plants exhibit a great variety of types of clonal growth. Moderate variation in clonal traits often exists even within species. The consequences of these variations for species interaction are of great interests to ecologists. In this paper, I address the small-leaved (phalanx) to large-leaved (guerrilla) variation in white clover ( Trifolium repens ), and discuss its consequences for species and genotype coexistence. I also address the clonal and sexual resource allocation variants within the large-leaved type. Small-leaved and large-leaved genotypes differ in various aspects of clonal growth. The large-leaved genotype displays greater phenotypic plasticity but is less physiologically integrated than the small-leaved genotype. We examined the consequences in a grazed sward, where white clover and zoysia grass coexist. In this sward, white clover is patchily distributed. We first tested the hypothesis that the large-leaved genotype is more advantageous in growth than the small-leaved genotype. Results from both common garden and competition experiments supported the hypothesis. Second, we tested the hypothesis that within large-leaved plants, the clonal subtype (which invests more resources to stolons but less in flower heads than the sexual one) is more advantageous than the sexual one because it is more competitive. This hypothesis was rejected. Both subtypes coexisted in the sward. This is probably because the sexual subtype is superior for interpatch migration than the clonal one. Both subtypes differ in advantages they offer for between-patch and within-patch processes, which promotes their coexistence. Finally, field monitoring of the behavior of a large-leaved clone is described. This monitoring was conducted in a moderately grazed sward, where microenvironmental heterogeneity is extremely high in time and space.     

Comparison of quantitative and molecular genetic variation of native vs. invasive populations of purple loosestrife (Lythrum salicaria L., Lythraceae)

Study of adaptive evolutionary changes in populations of invasive species can be advanced through the joint application of quantitative and population genetic methods. Using purple loosestrife as a model system, we investigated the relative roles of natural selection, genetic drift and gene flow in the invasive process by contrasting phenotypical and neutral genetic differentiation among native European and invasive North American populations ( Q _ST −  F _ST analysis). Our results indicate that invasive and native populations harbour comparable levels of amplified fragment length polymorphism variation, a pattern consistent with multiple independent introductions from a diverse European gene pool. However, it was observed that the genetic variation reduced during subsequent invasion, perhaps by founder effects and genetic drift. Comparison of genetically based quantitative trait differentiation ( Q _ST) with its expectation under neutrality ( F _ST) revealed no evidence of disruptive selection ( Q _ST >  F _ST) or stabilizing selection ( Q _ST <  F _ST). One exception was found for only one trait (the number of stems) showing significant sign of stabilizing selection across all populations. This suggests that there are difficulties in distinguishing the effects of nonadaptive population processes and natural selection. Multiple introductions of purple loosestrife may have created a genetic mixture from diverse source populations and increased population genetic diversity, but its link to the adaptive differentiation of invasive North American populations needs further research.     

Sequestration of organometallic compounds by synthetic and naturally occurring polycarboxylate ligands. Binding of monomethylmercury(II) by polyacrylic and alginic acids

Abstract

The sequestering capacity of synthetic and naturally occurring polycarboxylate ligands towards mono-methylmercury(II) was evaluated by stability quantitative data on the interaction of CH₃Hg⁺ with different molecular weight synthetic polyacrylates (2 and 20kDa average M.wt) and alginate (70–100 kDa) extracted from brown algae Macrocystis pyrifera. The influence of ionic medium was evaluated by measurements on the CH₃Hg⁺-polyacrylate systems in NaNO₃ medium at different ionic strengths (0.10, 0.25, 0.50 and 0.75 mol L^?1), and a Debye-HiJckel type equation was used for the dependence of complex formation constants on ionic strength. Measurements on the CH3Hg⁺ - alginate system were carried out at l = 0.10 mol L^?1 in NaNO₃ medium. By using the stability data, the sequestering capacity of both ligands towards monomethylmercury(II) was determined at different pH values. Results obtained show that the binding ability of polyacrylic ligands (PAA) is stronger than the alginate (AA), following the trend PAA (20 kDa)> PAA (2kDa)>AA.     

Density of Parasites in Various Organs and the Relation to Numbers of Trypomastigotes in the Blood during Acute Infections of Trypanosoma cruzi in Mice*

Quantitative methods were used to (a) determine the density of Trypanosoma cruzi in organs of CF₁ mice following intraperitoneal inoculation of 50,000 trypomastigotes of a Brazil strain of T. cruzi and (b) study the relation of the numbers of these intracellular stages to the numbers of trypomastigotes in the blood. Tissue stages (predominantly amastigotes) in heart, skeletal muscle (triceps), diaphragm, cerebrum, cerebellum, and musculature of stomach, duodenum, esophagus, jejunum, cecum, and rectum increased in numbers during the 1st 3 weeks of infection, reached maximum density 21–28 days after inoculation and subsequently declined in numbers until mice were histologically negative for intracellular parasites by 30–40 days. The density of tissue stages in the urinary bladder, uterine body, and ileum was similar with the exception that maximum numbers of parasites were observed slightly earlier at 15 days. The greatest density of intracellular stages was seen in heart, urinary bladder, diaphragm, and triceps muscle where mean counts of 44.6–60.0 × 10⁶ parasites/cc of muscle were recorded while maximum density of parasites in the uterine body, cerebrum, stomach, cerebellum, duodenum, esophagus, jejunum, ileum, cecum, and rectum was 13.0 × 10⁶/cc of muscle or less. Amastigotes were not observed in sections of lymph node, thymus, salivary glands, liver, spleen, or kidney and only a single pseudocyst containing 5 amastigotes was seen in lung. With the exception of the brain and lung, intracellular parasites were located exclusively in the musculature. Trypomastigotes in the blood increased during the 1st 3 weeks of infection, reached maximum numbers 21–28 days after initiation of infection, and subsequently decreased until by 30–40 days parasites were observed only rarely in the blood of a few animals. Thus generally close correlation was noted between the numbers of intracellular stages of T. cruzi in the organs and trypomastigotes in the blood throughout acute Chagas’ disease in mice as evidenced by the concomitant increase in numbers of both stages, the coincidence of days of maximum parasite levels, and the simultaneous decline in numbers of both stages. The mean number of parasites/pseudocyst section varied in the organs studied. Of the 15 positive organs studied, the pseudocyst sections in skeletal muscle contained the highest mean number of parasites (64.3 parasites/pseudocyst section) and those pseudocyst sections seen in the musculature of the small intestine contained the lowest mean number (5.5–6.8 parasites/pseudocyst section respectively in ileum and jejunum). Serial sections of skeletal muscle, heart, urinary bladder, and stomach revealed the largest pseudocysts in skeletal muscle while those in the musculature of the urinary bladder were the smallest.     

血吸附法浓缩NDV病毒及与其他几种方法的比较

用人O型红细胞吸附－释放病毒的方法纯化被感染的鸡胚尿囊液中的新城疫病毒（NDV）,然后分别对纯化的病毒液及弃去的上清进行血凝检测。结果表明,使用1％的红细胞悬液只能吸附部分病毒,损失较大,只有将红细胞悬液的浓度增加到20％时,才基本将病毒全部吸附住。同时还比较了差速离心,PEG沉淀,PEG包埋等方法。     

埃兹蛋白(Ezrin)及其突变体的原核表达与纯化

Thr567位点磷酸化是ezrin活化的必需条件。利用定点突变引物将T567突变为A或D,通过PCR扩增出相应的基因片段,将其通过T4连接酶连接至含His标签的原核表达载体pET-20b(+),构建了原核重组质粒pET-20b(+)-Ez WT,pET-20b(+)-EzT567A和pET-20b(+)-EzT567D。转化表达宿主大肠杆菌Rosseta后,用异丙基-β-硫代半乳糖诱导重组蛋白的表达。重组蛋白经亲和镍柱纯化以后,应用western blot鉴定纯化的融合蛋白。Ezrin野生型及其组成型激活和显性负突变质粒的成功构建及其目的蛋白His-Ez WT,His-EzT576A和His-EzT576D的成功表达纯化,为更深入地研究ezrin生物学功能奠定基础。