HPLC法分析山姜属植物中的8种活性成分

本文采用高效液相色谱方法,对18份16种山姜属植物中的8种抗血小板聚集活性成分进行了分析.这8种成分包括山姜素、豆蔻明、4',7-二羟基-5-甲氧基二氢黄酮、蜡菊亭、5,6-去氢醉椒素、4'-羟基去氢醉椒素、1,7-二(4-羟基苯基)-3-羟基-1,3,6-庚三烯-5-酮和1,7-二(4-羟基苯基)-3-羟基-1,3-庚二烯-5-酮.其中,对山姜素和豆蔻明进行了含量测定,其余6种成分进行了定性分析.结果表明这些山姜属植物有不同的化学成分特征.山姜素和豆蔻明是草豆蔻种子的主要特征成分,艳山姜种子中检测到较多的5,6-去氢醉椒素.     

升振山姜茎的黄酮类成分

为了解升振山姜(Alpinia hainanensis‘Shengzhen’)的化学成分,采用柱色谱技术从其茎中分离得到10个黄酮类化合物。经波谱分析,分别鉴定为(-)-乔松素(1)、(±)-山姜素(2)、(±)-7,4′-二羟基-5-甲氧基二氢黄酮(3)、4′,6′-二羟基-2′-甲氧基二氢查尔酮(4)、小豆蔻明(5)、蜡菊亭(6)、(+)-儿茶素(7)、(-)-表儿茶素(8)、原花青素A1(9)、原花青素A6(10)。体外活性测试表明,化合物1、3、5、7~10具有显著的ABTS自由基清除活性,化合物7~10具有显著的DPPH自由基清除活性。     

沼渣化学成分研究

采用硅胶、凝胶柱层析方法对鸡场沼渣甲醇提取物化学成分进行分离纯化,并结合波谱方法分析鉴定得到6个化合物,分别是:β-谷甾醇(1)、22β-羟基-12-齐墩果烯-3-酮(2)、21β-羟基-β-白檀酮(3)、29-羟基-12-土当归烯-3,22-二酮(4)、17β-雌二醇(5)和S(-)-雌马酚(6)。这些成分均首次从鸡场沼渣中分离得到。有研究表明,21β-羟基-β-白檀酮在IC5027.4μM就具有很好的抗肠贾第虫(Giardia intestinalis)活性。许多流行病学研究和动物实验、体外实验表明,S(-)-雌马酚有助于妇女更年期症状的改善、保护心血管、缓解骨质疏松症及抗乳腺癌、前列腺癌等保护作用。     

落叶松针叶化学成分研究

该研究采用硅胶柱色谱、半制备型高效液相色谱和重结晶等方法对落叶松针叶乙酸乙酯萃取物进行分离纯化,利用NMR、MS现代波谱技术结合相关文献报道对分离得到的化合物进行结构鉴定,并对提取浸膏的抑菌活性进行了测试。结果表明:从落叶松针叶乙酸乙酯萃取物中分离得到15个化合物,分别鉴定为Larixol (1)、(2R)-5,4'-二羟基-6-甲基-7-甲氧基-黄酮(2)、2',4'-二羟基-4,6'-二甲氧基二氢查尔酮(3)、2',4-二羟基-4',6'-二甲氧基查尔酮(4)、2',4'-二羟基-4,6'-二甲氧基查尔酮(5)、异鼠李素(6)、4',5-二羟基-7-甲氧基-8-甲基黄酮(7)、山奈酚(8)、β-谷甾醇(9)、豆甾醇(10)、胡萝卜苷(11)、香草酸(12)、对羟基苯甲酸(13)、二甲基罗汉松脂素(14)、15-二十九烷醇(15)。其中,化合物2,4,5和7为首次从该属植物中分离得到。抑菌活性实验结果显示,乙酸乙酯萃取浸膏在浓度为5~100 mg·mL-1时对大肠杆菌、枯草芽孢杆菌、蜡样芽孢杆菌和金黄色葡萄球菌的抑菌率分别为55%~70%、53%~72%、61%~71%和33%~65%。上述结果为更加深入探究落叶松针叶化学成分和药理活性提供了一定理论依据。     

Δ5-3β,7β-二羟基甾醇及其C-7差向异构体波谱特征及胆碱酯酶的抑制活性

本文对Δ5-3β,7β-二羟基甾醇(1~3)和Δ5-3β,7α-二羟基甾醇(4~6)的一些核磁共振波谱特征进行了比较。活性测试表明化合物1~6对乙酰胆碱酯酶(AChE)无明显的抑制活性,对丁酰胆碱酯酶(BuChE)则有较强的抑制活性,其中24-亚甲基胆甾-5-烯-3β,7α-二醇(6)的IC50值为9.5μM。通过活性数据比较我们发现7α-羟基甾醇对丁酰胆碱酯酶的抑制活性明显比相应的7β-羟基甾醇高。我们通过计算7位羟基和四环平面之间的二面角角度来尝试解释这些活性差别。     

蟹爪叶盾蕨石油醚提取物的成分分析及抗菌活性研究

为了研究蟹爪叶盾蕨(Neolepisorus ovatus(Bedd.)Ching f. doryopteris(Christ)Ching)石油醚提取物的化学组成及抗菌活性,采用气相色谱-质谱法分析蟹爪叶盾蕨石油醚提取物的成分,采用琼脂平板打孔法检测提取物对大肠杆菌、金黄色葡萄球菌、藤黄八叠球菌的抑制活性。从蟹爪叶盾蕨石油醚提取物中鉴定出38种化学成分,占出峰总数的92. 76%,其中豆甾-4-烯-3-酮(19. 83%)、何帕烯(16. 40%)、β-香树脂酮(14. 93%)等甾体和萜类化合物含量丰富。抑菌活性结果显示,蟹爪叶盾蕨石油醚提取物对藤黄八叠球菌的抑菌圈为(7. 78±0. 55)cm,对大肠杆菌、金黄色葡萄球菌、白色念珠菌没有抑制作用。所鉴定的化合物均首次从蟹爪叶盾蕨检测到,蟹爪叶盾蕨石油醚提取物对藤黄八叠球菌有抑制作用。此研究结果为该植物的开发利用提供了科学依据。     

一株Streptosporangium sp.次生代谢产物研究Ⅰ

通过对Streptosporangium sp．菌株发酵液的初步分离纯化,得到三个化合物,由波谱解析鉴定为：4,6-二甲基-6-羟基-庚烯-2酮(1),2,6-二甲基-2,6-二羟基-庚4酮(2),3,6-二异丙基-2,5-二酮哌嗪(3)。由活体试验证明2和3对粘虫有一定的抑制活性。     

康美肤烧伤膏抗菌活性

目的观察康美肤烧伤膏的抗菌作用。方法采用试管稀释法测定康美肤烧伤膏对常见致病菌的最低抑菌浓度(M IC)及对大鼠Ⅱ度烧烫伤创面接种金黄色葡萄球菌的实验治疗模型创面菌落计数的影响。结果康美肤烧伤膏对常见致病菌的M IC范围在3.90~62.50 g/L。结论康美肤烧伤膏具有较强的抗菌活性和较广的抗菌谱。     

Analysis of compounds extracted from male Apolygus lucorum

采用气质联用和嗅觉仪对分部解剖的绿盲蝽Apolygus lucorum (Meyer-Dür)雄虫体外挥发物进行鉴定和生测.结果表明:绿盲蝽雄虫浸提物中的主要组分有13种,包括醇类、酸类和酯类.相对含量较高的依次有丁酸已酯、反-2-丁酸已烯酯和已醇.绿盲蝽雄虫从交配不活跃期进入活跃期,其体内的丁酸已酯、反-2-丁酸已烯酯和已醇的含量都明显变化,其中丁酸已酯和反-2-丁酸已烯酯明显增加,而已醇的含量减少,表明绿盲蝽雄虫在交配活跃期,可能有大量的丁酸已酯和反-2-丁酸已烯酯释放到体外.比较绿盲蝽雄虫的不同部位的浸提物的含量,发现丁酸已酯、反-2-丁酸已烯酯和已醇主要存在于虫体胸部.嗅觉反应测试中绿盲蝽雌虫对丁酸已酯和反-2-丁酸已烯酯有明显的趋性,同时含量很少的丁酸庚酯对雌虫有明显引诱作用.因此推测丁酸已酯、反-2-丁酸已烯酯和丁酸庚酯可能是绿盲蝽雄虫释放到体外的挥发性引诱成分,并主要由胸部内的腺体分泌.     

羊角天麻化学成分及β-羟高铁血红素形成抑制活性研究

为探究羊角天麻(Dobinea delavayi)的β-羟高铁血红素形成抑制活性成分,本实验采用硅胶、Sephadex LH-20柱色谱等方法进行化合物的纯化分离,通过理化性质及波谱数据鉴定化合物结构。结果从羊角天麻中分离得到12个化合物,分别鉴定为3,4,2′,4′-四羟基二氢查尔酮(1)、紫铆花素(2)、3,4,2′,4′,α-五羟基查尔酮(3)、金色草素(4)、芒果苷(5)、没食子酸(6)、二十四亚甲基环阿尔廷醇(7)、6β-羟基-豆甾-4-烯-3-酮(8)、β-谷甾醇(9)、胡萝卜苷(10)、棕榈酸甲酯(11)、1-棕榈酸单甘油酯(12),其中化合物1~4、6~8均为首次九子母属植物中分离得到。活性研究结果显示,化合物1~6均具有β-羟高铁血红素形成抑制活性,其中黄酮类化合物2~4具有较强的抑制活性,其IC50分别为120.3、61.5、56.0μg/mL。     

Preparation of hair for measurement of elements by inductively coupled plasma-mass spectrometry (ICP-MS)

The preparation of hair for the determination of elements is a critical component of the analysis procedure. Open-beaker, closedvessel microwave, and flowthrough microwave digestion are methods that have been used for sample preparation and are discussed. A new digestion method for use with inductively coupled plasma-mass spectrometry (ICP-MS) has been developed. The method uses 0.2 g of hair and 3 mL of concentrated nitric acid in an atmospheric pressurelow-temperature microwave digestion (APLTMD) system. This preparation method is useful in handling a large numbers of samples per day and may be adapted to hair sample weights ranging from 0.08 to 0.3 g. After digestion, samples are analyzed by ICP-MS to determine the concentration of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Se, Rb, Sr, Zr, Mo, Pd, Ag, Cd, Sn, Sb, I, Cs, Ba, Pt, Au, Hg, Tl, Pb, Bi, Th, and U. Benefits of the APLTMD include reduced contamination and sample handling, and increased precision, reliability, and sample throughput.     

Genetic Manipulation in Δku80 Strains for Functional Genomic Analysis of Toxoplasma gondii

Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene function and phenotype(s). The development of mutant strains with targeted gene deletions, targeted mutations, complemented gene function, and/or tagged genes provides powerful strategies to address gene function, particularly if these genetic manipulations can be efficiently targeted to the gene locus of interest using integration mediated by double cross over homologous recombination.Due to very high rates of nonhomologous recombination, functional genomic analysis of Toxoplasma gondii has been previously limited by the absence of efficient methods for targeting gene deletions and gene replacements to specific genetic loci. Recently, we abolished the major pathway of nonhomologous recombination in type I and type II strains of T. gondii by deleting the gene encoding the KU80 protein^1,2. The Δku80 strains behave normally during tachyzoite (acute) and bradyzoite (chronic) stages in vitro and in vivo and exhibit essentially a 100% frequency of homologous recombination. The Δku80 strains make functional genomic studies feasible on the single gene as well as on the genome scale^1-4.Here, we report methods for using type I and type II Δku80Δhxgprt strains to advance gene targeting approaches in T. gondii. We outline efficient methods for generating gene deletions, gene replacements, and tagged genes by targeted insertion or deletion of the hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) selectable marker. The described gene targeting protocol can be used in a variety of ways in Δku80 strains to advance functional analysis of the parasite genome and to develop single strains that carry multiple targeted genetic manipulations. The application of this genetic method and subsequent phenotypic assays will reveal fundamental and unique aspects of the biology of T. gondii and related significant human pathogens that cause malaria (Plasmodium sp.) and cryptosporidiosis (Cryptosporidium).     

A phylogenetic analysis of 100+ genera and 50+ families of euasterids based on morphological and molecular data with notes on possible higher level morphological synapomorphies

 A data matrix of 143 morphological and chemical characters for 142 genera of euasterids according to the APG system was compiled and complemented with rbcL and ndhF sequences for most of the genera. The data were subjected to parsimony analysis and support was assessed by bootstrapping. Strict consensus trees from analyses of morphology alone and morphology + rbcL + ndhF are presented. The morphological data recover several groups supported by molecular data but at the level of orders and above relationships are only superficially in agreement with molecular studies. The analyses provide support for monophyly of Gentianales, Aquifoliales, Apiales, Asterales, and Dipsacales. All data indicate that Adoxaceae are closely related to Dipsacales and hence they should be included in that order. The trees were used to assess some possible morphological synapomorphies for euasterids I and II and for the orders of the APG system. Euasterids I are generally characterised by opposite leaves, entire leaf margins, hypogynous flowers, “early sympetaly” with a ring-shaped corolla primordium, fusion of stamen filaments with the corolla tube, and capsular fruits. Euasterids II often have alternate leaves, serrate-dentate leaf margins, epigynous flowers, “late sympetaly” with distinct petal primordia, free stamen filaments, and indehiscent fruits. It is unclear which of these characters represent synapomorphies and symplesiomorphies for the two groups, respectively, and there are numerous expections to be interpreted as reversals and parallelisms. Received August 28, 2000 Accepted August 7, 2001     

Mechanisms and ecological consequences of plant defence induction and suppression in herbivore communities

Background Plants are hotbeds for parasites such as arthropod herbivores, which acquire nutrients and energy from their hosts in order to grow and reproduce. Hence plants are selected to evolve resistance, which in turn selects for herbivores that can cope with this resistance. To preserve their fitness when attacked by herbivores, plants can employ complex strategies that include reallocation of resources and the production of defensive metabolites and structures. Plant defences can be either prefabricated or be produced only upon attack. Those that are ready-made are referred to as constitutive defences. Some constitutive defences are operational at any time while others require activation. Defences produced only when herbivores are present are referred to as induced defences. These can be established via de novo biosynthesis of defensive substances or via modifications of prefabricated substances and consequently these are active only when needed. Inducibility of defence may serve to save energy and to prevent self-intoxication but also implies that there is a delay in these defences becoming operational. Induced defences can be characterized by alterations in plant morphology and molecular chemistry and are associated with a decrease in herbivore performance. These alterations are set in motion by signals generated by herbivores. Finally, a subset of induced metabolites are released into the air as volatiles and function as a beacon for foraging natural enemies searching for prey, and this is referred to as induced indirect defence.Scope The objective of this review is to evaluate (1) which strategies plants have evolved to cope with herbivores and (2) which traits herbivores have evolved that enable them to counter these defences. The primary focus is on the induction and suppression of plant defences and the review outlines how the palette of traits that determine induction/suppression of, and resistance/susceptibility of herbivores to, plant defences can give rise to exploitative competition and facilitation within ecological communities “inhabiting” a plant.Conclusions Herbivores have evolved diverse strategies, which are not mutually exclusive, to decrease the negative effects of plant defences in order to maximize the conversion of plant material into offspring. Numerous adaptations have been found in herbivores, enabling them to dismantle or bypass defensive barriers, to avoid tissues with relatively high levels of defensive chemicals or to metabolize these chemicals once ingested. In addition, some herbivores interfere with the onset or completion of induced plant defences, resulting in the plant’s resistance being partly or fully suppressed. The ability to suppress induced plant defences appears to occur across plant parasites from different kingdoms, including herbivorous arthropods, and there is remarkable diversity in suppression mechanisms. Suppression may strongly affect the structure of the food web, because the ability to suppress the activation of defences of a communal host may facilitate competitors, whereas the ability of a herbivore to cope with activated plant defences will not. Further characterization of the mechanisms and traits that give rise to suppression of plant defences will enable us to determine their role in shaping direct and indirect interactions in food webs and the extent to which these determine the coexistence and persistence of species.     

Angiosperm ovules: diversity, development, evolution

Background

Ovules as developmental precursors of seeds are organs of central importance in angiosperm flowers and can be traced back in evolution to the earliest seed plants. Angiosperm ovules are diverse in their position in the ovary, nucellus thickness, number and thickness of integuments, degree and direction of curvature, and histological differentiations. There is a large body of literature on this diversity, and various views on its evolution have been proposed over the course of time. Most recently evo–devo studies have been concentrated on molecular developmental genetics in ovules of model plants.

Scope

The present review provides a synthetic treatment of several aspects of the sporophytic part of ovule diversity, development and evolution, based on extensive research on the vast original literature and on experience from my own comparative studies in a broad range of angiosperm clades.

Conclusions

In angiosperms the presence of an outer integument appears to be instrumental for ovule curvature, as indicated from studies on ovule diversity through the major clades of angiosperms, molecular developmental genetics in model species, abnormal ovules in a broad range of angiosperms, and comparison with gymnosperms with curved ovules. Lobation of integuments is not an atavism indicating evolution from telomes, but simply a morphogenetic constraint from the necessity of closure of the micropyle. Ovule shape is partly dependent on locule architecture, which is especially indicated by the occurrence of orthotropous ovules. Some ovule features are even more conservative than earlier assumed and thus of special interest in angiosperm macrosystematics.     

Genome Similarity Implies that Citrus-Parasitic Burrowing Nematodes do not Represent a Unique Species

Burrowing nematodes from Central America, Dominican Republic, Florida, Guadeloupe, Hawaii, and Puerto Rico were characterized for their ability to parasitize citrus, but citrus parasites were found only in Florida. Sequence tag sites originally amplified from a citrus-parasitic burrowing nematode were polymorphic among 37 burrowing nematode isolates and were not correlated with citrus parasitism, nematode isolate collection site, or amplification of a 2.4-kb sequence tag site (DK#1). Results of a RAPD analysis and characterization of the isozymes phosphoglucose isomerase, lactate dehydrogenase, and malate dehydrogenase indicated that the burrowing nematode isolates were highly similar. Citrus parasitism in Florida appears to be associated with limited changes in the burrowing nematode genome. Findings did not substantiate a previous report that R. citrophilus was present in Hawaii. Overall, these data do not support assignment of sibling species status to burrowing nematodes that differ with respect to citrus parasitism.     

A Simple Protocol for Platelet-mediated Clumping of Plasmodium falciparum-infected Erythrocytes in a Resource Poor Setting

P. falciparum causes the majority of severe malarial infections. The pathophysiological mechanisms underlying cerebral malaria (CM) are not fully understood and several hypotheses have been put forward, including mechanical obstruction of microvessels by P. falciparum-parasitized red blood cells (pRBC). Indeed, during the intra-erythrocytic stage of its life cycle, P. falciparum has the unique ability to modify the surface of the infected erythrocyte by exporting surface antigens with varying adhesive properties onto the RBC membrane. This allows the sequestration of pRBC in multiple tissues and organs by adhesion to endothelial cells lining the microvasculature of post-capillary venules ¹. By doing so, the mature forms of the parasite avoid splenic clearance of the deformed infected erythrocytes ² and restrict their environment to a more favorable low oxygen pressure ³. As a consequence of this sequestration, it is only immature asexual parasites and gametocytes that can be detected in peripheral blood.Cytoadherence and sequestration of mature pRBC to the numerous host receptors expressed on microvascular beds occurs in severe and uncomplicated disease. However, several lines of evidence suggest that only specific adhesive phenotypes are likely to be associated with severe pathological outcomes of malaria. One example of such specific host-parasite interactions has been demonstrated in vitro, where the ability of intercellular adhesion molecule-1 to support binding of pRBC with particular adhesive properties has been linked to development of cerebral malaria ^4,5. The placenta has also been recognized as a site of preferential pRBC accumulation in malaria-infected pregnant women, with chondrotin sulphate A expressed on syncytiotrophoblasts that line the placental intervillous space as the main receptor ⁶. Rosetting of pRBC to uninfected erythrocytes via the complement receptor 1 (CD35)^7,8 has also been associated with severe disease ⁹.One of the most recently described P. falciparum cytoadherence phenotypes is the ability of the pRBC to form platelet-mediated clumps in vitro. The formation of such pRBC clumps requires CD36, a glycoprotein expressed on the surface of platelets. Another human receptor, gC1qR/HABP1/p32, expressed on diverse cell types including endothelial cells and platelets, has also been shown to facilitate pRBC adhesion on platelets to form clumps ¹⁰. Whether clumping occurs in vivo remains unclear, but it may account for the significant accumulation of platelets described in brain microvasculature of Malawian children who died from CM ¹¹. In addition, the ability of clinical isolate cultures to clump in vitro was directly linked to the severity of disease in Malawian ¹² and Mozambican patients ¹³, (although not in Malian ¹⁴).With several aspects of the pRBC clumping phenotype poorly characterized, current studies on this subject have not followed a standardized procedure. This is an important issue because of the known high variability inherent in the assay ¹⁵. Here, we present a method for in vitro platelet-mediated clumping of P. falciparum with hopes that it will provide a platform for a consistent method for other groups and raise awareness of the limitations in investigating this phenotype in future studies. Being based in Malawi, we provide a protocol specifically designed for a limited resource setting, with the advantage that freshly collected clinical isolates can be examined for phenotype without need for cryopreservation.     

Assessing burrowing, nest construction, and hoarding in mice

Deterioration in the ability to perform "Activities of daily living" (ADL) is an early sign of Alzheimer's disease (AD). Preclinical behavioural screening of possible treatments for AD currently largely focuses on cognitive testing, which frequently demands expensive equipment and lots of experimenter time. However, human episodic memory (the most severely affected aspect of memory in AD) is different to rodent memory, which seems to be largely non-episodic. Therefore the present ways of screening for new AD treatments for AD in rodents are intrinsically unlikely to succeed. A new approach to preclinical screening would be to characterise the ADL of mice. Fortuitously, several such assays have recently been developed at Oxford, and here the three most sensitive and well-characterised are presented. Burrowing was first developed in Oxford. It evolved from a need to develop a mouse hoarding paradigm. Most published rodent hoarding paradigms required a distant food source to be linked to the home cage by a connecting passage. This would involve modifying the home cage as well as making a mouse-proof connecting passage and food source. So it was considered whether it would be possible to put the food source inside the cage. It was found that if a container was placed on the floor it was emptied by the next morning., The food pellets were, however, simply deposited in a heap at the container entrance, rather than placed in a discrete place away from the container, as might be expected if the mice were truly hoarding them. Close inspection showed that the mice were performing digging ("burrowing") movements, not carrying the pellets in their mouths to a selected place as they would if truly hoarding them. Food pellets are not an essential substrate for burrowing; mice will empty tubes filled with sand, gravel, even soiled bedding from their own cage. Moreover, they will empty a full tube even if an empty one is placed next to it. Several nesting protocols exist in the literature. The present Oxford one simplifies the procedure and has a well-defined scoring system for nest quality. A hoarding paradigm was later developed in which the mice, rather than hoarding back to the real home cage, were adapted to living in the "home base" of a hoarding apparatus. This home base was connected to a tube made of wire mesh, the distal end of which contained the food source. This arrangement proved to yield good hoarding behaviour, as long as the mice were adapted to living in the "home base" during the day and only allowed to enter the hoarding tube at night.     

日本北海道虻类雌性外生殖器形态(双翅目：虻科)(英文)

【目的】利用日本北海道虻类评估和验证外生殖器在分类学上的意义。【方法】将虻类成虫标本浸渍在生理盐水中并置于双目显微镜下通过针和镊子在培养皿中进行解剖并绘图,观察第9背板、第10背板、尾叶、第8腹板、受精囊、受精囊管及生殖叉器的形态特征。【结果】在日本北海道共记录了虻科(Tabanidae) 3亚科7属38种。我们观察并描述了3亚科其中的6属24种的雌性外生殖器的主要特征。亚科之间存在明显差异;然而在一般情况下属之间很难建立一种方法来确定共同点;种之间只有在斑虻属Chrysops中有相似之处,其他属中则比较多样化。因此,亚科鉴定根据第9背板、第8腹板及受精囊足以进行区分,属及种鉴定需要结合第9背板、第10背板、尾叶、第8腹板、受精囊、受精囊管及生殖叉器各自的特征组合在一起才能区分开来。我们也制作了虻类外生殖器的检索表。【结论】和许多其他昆虫一样,外生殖器是虻科的重要分类特征,对于促进分类学和系统学的发展具有重要意义。本研究首次对分布在日本北海道的虻科雌性外生殖器进行了系统研究。     

外泌体在白血病中的重要调控作用

目前,白血病复发是患者死亡的主要原因之一。肿瘤细胞和微环境的相互作用,以及隐匿在骨髓中的肿瘤干细胞,促进了白血病的复发和向淋巴组织的转移,因此白血病的治疗、转移和复发问题受到广泛关注。外泌体是由绝大多数细胞分泌的双层脂质膜囊泡,可以调控细胞间的交流和信息传递。在白血病细胞、基质细胞和内皮细胞之间的相互联系中都涉及到外泌体,白血病细胞来源的外泌体存在于白血病患者的血浆中,能把其携带的白血病相关抗原及微小RNA呈递给靶细胞,促进白血病肿瘤细胞的增殖,有助于肿瘤细胞实现免疫逃避,保护白血病细胞抵抗化疗药物导致的细胞毒性作用,促进血管生成及肿瘤细胞的迁移。因此,外泌体与白血病的转移、治疗及预后密切相关,可以用来检测和监测白血病的进展。本文综述了外泌体的来源、形成与分泌机制,以及外泌体在白血病发生前、发展中、预后和免疫治疗中所扮演的重要角色。