菌根共生体形成过程中的信号识别与转导机制

在菌根共生体建立过程中存在信号分子的多重性和信号通路的多样性以及共牛体特异基因的表达调控,从分子水平上揭示了菌根整个发育过程。     

丛枝菌根形成过程及其信号转导途径

丛枝菌根是由一类土壤中古老的丛枝菌根真菌与植物根系形成的互利互惠共生体。通过共生作用丛枝菌根真菌帮助宿主植物提高水和矿质营养（特别是磷）的吸收效率。作为回报,大约20%的光合作用产物被转移到丛枝菌根真菌中,供其完成自身的生活史。丛枝菌根形成的过程中,需要植物与丛枝菌根真菌之间进行一系列信号分子的识别、交换以及信号转导作用,这一过程由一系列植物和菌根真菌的基因控制。首先,植物会分泌一种植物激素——独角金内酯来诱导菌根真菌加速分支,而菌根真菌也会分泌脂质几丁寡糖促进植物与其形成菌根。加速分支的菌根真菌接触到植物根部以后,会附着在植物根的表皮并形成附着胞,通过附着胞穿透植物根的表皮,最后进入维管组织附近的皮层细胞并在其中不断进行二叉分支,形成特有的丛枝结构。通过对模式植物共生现象的研究,已经发现很多植物基因参与到共生形成的信号转导过程中,包括早期植物反应的基因、菌根与根瘤共生共同需要的转导因子以及菌根特异的信号分子等。本文对菌根的形成过程及信号转导途径进行详细的介绍,为人们深入研究菌根关系提供参考。     

外生菌根共生:共生真菌多样性及菌根形成的分子机制

大约2%的维管植物能够与17～18个目约280个属的真菌形成外生菌根关系.外生菌根关系的形成、宿主植物的专一化和宿主转移等事件可能是共生真菌物种分化的重要驱动力.比较基因组学研究发现,外生菌根真菌丢失了大量与植物细胞壁物质降解相关的基因.在外生菌根形成过程中,真菌与宿主植物之间借助多样化的信号分子完成相互识别,并且外生菌根真菌能够借助分泌效应蛋白抑制宿主植物的防御反应,促进菌根形成.本文对外生菌根真菌的多样性和分布规律,以及外生菌根形成的分子机制等方面进行了综述,并据此对后续研究提出展望.     

丛枝菌根真菌诱导植物信号物质研究进展

丛枝菌根(AM)真菌侵染植物根系形成菌根共生体过程中能诱导植物合成多种信号物质,如水杨酸(SA)、茉莉酸(JA)、类黄酮、一氧化氮(NO)和过氧化氢(H2O2)等。这些信号分子的传导途径和作用机制备受关注。本文从AM真菌诱导植物信号物质的种类和数量入手,探讨这些信号分子在植物体内的传导途径、生理效应和可能的作用机制,旨在为研究AM真菌与植物之间的共生关系、功能与进化等提供依据。     

植物中丛枝菌根形成的信号途径研究进展

丛枝菌根(arbuscular mycorrhizal, AM)共生是丛枝菌根真菌与大多数陆地植物的根系之间形成的一种互利共生关系。植物给菌根真菌提供碳水化合物; 作为回报, 菌根真菌能够增强植物对矿质营养元素(尤其是磷)的吸收。菌根的形成过程是一系列信号交换和转导的结果, 具有严格并且一致的顺序。本文以植物中菌根形成的信号途径为主线, 对菌根真菌的形成过程和信号转导途径及其方式进行了分析和讨论。高等植物中菌根形成的信号途径与豆科植物的结瘤信号途径部分共享, 并且与钙离子信号途径相关, 但前者更为广泛。尽管该途径中很多过程目前还不十分清楚, 但是相信在不久的将来就可以揭开菌根形成过程中的众多谜团。     

植物中丛枝菌根形成的信号途径研究进展

丛枝菌根(arbuscular mycorrhizal,AM)共生是丛枝菌根真菌与大多数陆地植物的根系之间形成的一种互利共生关系。植物给菌根真菌提供碳水化合物;作为回报,菌根真菌能够增强植物对矿质营养元素(尤其是磷)的吸收。菌根的形成过程是一系列信号交换和转导的结果,具有严格并且一致的顺序。本文以植物中菌根形成的信号途径为主线,对菌根真菌的形成过程和信号转导途径及其方式进行了分析和讨论。高等植物中菌根形成的信号途径与豆科植物的结瘤信号途径部分共享,并且与钙离子信号途径相关,但前者更为广泛。尽管该途径中很多过程目前还不十分清楚,但是相信在不久的将来就可以揭开菌根形成过程中的众多谜团。     

丛枝菌根真菌脂类代谢对共生信号调控的响应和反馈

丛枝菌根(AM)真菌是自然生态系统中分布最为广泛的真菌之一,在自然界物质循环和能量流动中发挥着重要作用。经过长期的协同进化,AM真菌和宿主植物之间形成了完美的互惠互利的共生关系,而真菌的脂类代谢可能是揭示共生秘密的关键所在。本文综述了AM真菌脂类代谢在共生关系建立和维持中关键作用的最新研究进展,重点探讨了AM真菌脂类代谢对共生信号调控的响应和反馈机制,主要包括:AM真菌脂类存储和释放对共生和非共生状态的响应,以及脂类代谢产物变化与共生营养传递之间的关系;脂类分解过程在共生建立初期对信号分子调控发生的响应,以及相应的物质转化和能量代谢;菌根共生互惠互利关系维持中,真菌脂类代谢与信号分子交流通道的相互渗透和影响。本文对于理解菌根共生机制,促进菌根在生产中的应用具有促进作用。     

丛枝菌根共生关系的信号机制研究进展

在植物与微生物的共生体中,最广泛的互惠共生体就是丛枝菌根.真菌在植物根系形成菌根后,菌丝通过根的皮层细胞获取植物提供的碳源,同时将矿物营养和水从土壤转运到皮层细胞,这种共生过程的研究在生物多样性的保护、陆生植物的起源与演化、退化生态系统的修复与重建以及农业、林业和园艺业的应用具有重要的意义.近年来丛枝菌根真菌与植物根系建立共生关系的信号传导途径和作用机制备受关注,也取得了突破性的进展.本文对丛枝菌根真菌与植物根系在共生关系形成、营养交换以及防御方面的分子信号和细胞方面的研究进展进行综述,并对发展前景作以展望.     

丛枝菌根共生的信号转导及其相关基因

大多数植物根系能够与某些真菌形成相互依存、互惠互利的菌根共生关系.植物在提供给丛枝菌根真菌赖以生存的碳源的同时,也通过真菌从土壤中吸取矿质营养.丛枝菌根能够促进植物生长,提高植物抗逆性和抵御外界不良环境,对提高农林业生产效率、增强生态系统稳定性及维护生物多样性具有重要的意义.菌根的形成是一系列信号分子交换传递和共生相关基因表达调控的结果.在信号转导途径中,共生受体样蛋白激酶、离子通道和钙/钙调依赖性蛋白激酶基因的表达对菌根的形成是不可或缺的.就丛枝菌根共生的信号转导机制以及信号途径中3个必需基因的结构、功能及研究现状进行了综述.     

植物与丛枝菌根真菌在共生早期的信号交流

摘要:丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)与大多数陆生植物互利共生具有广泛的生理生态学意义,而这一生态学功能背后的共生机制我们知之甚少。已探明AM形成前宿主植物根分泌的独脚金内酯促进AMF菌丝分支,分泌的角质单体促进AMF 在宿主根中定植;同时,菌根真菌的分支菌丝释放出脂质几丁糖(lipochitooligosaccharides,LCOs)和短链几丁质寡聚物(short-chain chitin oligomers,COs)信号分子诱导宿主基因表达、侧根发育以及形成Ca2+振荡,它们相互作用共同促进AM形成。在能同时形成菌根和根瘤的蒺藜苜蓿(Medicago truncatula)和日本百脉根(Lotus corniculatus)植物中,根瘤共生体形成过程所需的若干基因与菌根形成所需的基因有关。这些研究成果为全面揭示菌根共生体发生过程的信号转导奠定了基础。本文对目前国内外宿主植物与AM真菌之间的信号物质及其功能、相关基因及其调控功能等进行了综述,旨在为AM真菌共生早期的信号交流研究提供有价值的参考。     

激光联合注射曲安奈德治疗婴幼儿血管瘤的疗效分析

目的：分析激光联合注射曲安奈德治疗婴幼儿血管瘤的疗效。方法：将120例处于增殖期血管瘤患儿分成观察组和对照组各60例,观察组给予激光联合注射曲安奈德治疗,对照组采用激光治疗,比较两组患者的治疗疗效。结果：观察组和对照组的总有效率分别为96．7％和66．7％,两组比较具有显著差异,P〈0．05;对于表浅病灶,观察组治疗的有效率为96．8％,对照组为84．8％,两组之间无差异,P〉0．05;对于深部病灶,观察组和对照组的总有效率分别为96．6％和44．4％,具有显著差异（P〈0．05）。结论：激光联合注射曲安奈德治疗婴幼儿血管瘤具有较好的疗效,尤其对深部增殖期的血管瘤具有较好的效果,适合在临床推广应用。     

Effects of source of fibre on the development and pH of the gastrointestinal tract of broilers

The effects of different sources of dietary fibre on gastrointestinal tract (GIT) development and digesta pH were studied in 25-day-old broilers. There were four diets: a control diet low in fibre content (37.3 g neutral detergent fibre and 16.0 g acid detergent fibre/kg) and three additional diets in which 30 g/kg of cellulose (CEL), sugar beet pulp (SBP) or oat hulls (OH) were included at the expenses of sepiolite (a complex magnesium silicate clay). The relative weight (RW, %BW) of the GIT was greater with the SBP – than with the CEL – and the control diets. Also, gizzard RW was higher with the diet containing OH than with the diet containing CEL or the control diets, with the SBP diet being intermediate (P≤0.001). Fibre inclusion modified the pH of the GIT (P≤0.05) but the effects depended on the type of fibre. Crop pH was higher and proventriculus pH lower with SBP than with the other diets. However, gizzard pH was reduced with SBP and OH but not with CEL (P≤0.05). The pH of the digesta of the duodenum was similar for all diets but that of the jejunum, Meckel's diverticulum and ileum increased with SBP and decreased with CEL inclusion (P≤0.05). We concluded that dietary fibre affects the development and pH value of the different segments of GIT and that the effects differ according to the physico-chemical characteristics of the source of fibre used.     

Determination of binding constants of lipopolysaccharides of different structure with chitosan

The interaction of endotoxins--lipopolysaccharides (LPS) different in degree of the O-specific chain polymerization--with 20- and 130-kD chitosan was studied using the competitive binding of LPS with the complex of chitosan-anionic dye (tropaeolin 000-2) and the direct binding of (125)I-labeled LPS with chitosan immobilized on Sepharose 4B. The interaction of 20-kD chitosan with LPS was non-cooperative, and immobilization of the polycation on Sepharose resulted in its binding to (125)I-labeled LPS with a positive cooperativity. The interaction of LPS possessing a long O-specific chain with 130-kD chitosan was characterized by negative cooperativity. Binding constants of LPS with the polycation and the number of binding sites per amino group of chitosan were determined. The interaction affinity and stoichiometry of the LPS-chitosan complexes significantly depend on the LPS structure and concentration in the reaction mixture. The increase in the length of carbohydrate chains of LPS results in increase in the binding constants and decrease in the bound endotoxin amount.     

多发性抽动症的脑电图观察

目的:进一步探究脑电图对多发性抽动症患儿的辅助诊断价值。方法:本文对45例多发性抽动症患儿进行脑电图描记录,选择理想信号段进行分析。结果发现24例异常,异常率为53.3%。其中中度异常6例,占25%,脑波表现为在高幅δ、θ波长程阵发的背景上偶发尖波;轻度异常18例,占75%,表现背景脑波频率变慢,出现高幅δ、θ波及活动,伴短程出现;正常21例,较同年龄组的脑电图调节差,波形杂乱。结论:脑电图反映脑功能活动,通过计算机分析方法可提供更多信息,并且脑电图操作方便,无痛无创,易于被儿童接受,在多发性抽动症早期临床诊断中具有较高的应用价值。     

棉铃虫钙粘蛋白N端多肽多克隆抗体制备及对Bt抗性的初步检测

用重组表达的棉铃虫Helicoverpa armigera(Hübner)中肠钙粘蛋白N端多肽片段制备兔多克隆抗体,并利用其对Bt抗性进行鉴定。通过RT-PCR方法对棉铃虫中肠钙粘蛋白N端多肽的基因片段Cad285进行PCR扩增,将其克隆到pET-30a原核表达载体中,在大肠杆菌BL21(DE3)中经IPTG诱导表达,得到35ku的重组融和蛋白,融合表达的包涵体经过变性、Ni-NTA柱亲和纯化、复性等方法处理包涵体,获得可溶性纯化蛋白,用纯化后蛋白免疫新西兰兔制备多克隆抗体,ELISA检测其效价高于1∶16000;利用最终获得的多克隆抗体对室内纯合Bt抗/感品系的棉铃虫中肠钙粘蛋白进行Western blot分析,结果显示敏感和抗性品系之间有明显差异,表明其能够应用对Bt抗性进行初步检测。     

A test of the randomness of paternity of members of maternal sibships in six captive groups of rhesus monkeys (Macaca mulatta)

Results of previous studies have shown that in captive groups of rhesus monkeys (Macaca mulatto)fathers associate more frequently with their own offspring than with those of other males and that mothers are most permissive of physical contact between their own infant and a juvenile when that juvenile shares the same father with her infant. These two observations suggest that the identity of offspring born in captive groups of rhesus monkeys is recognized by at least some adult members of the group. Consistent patterns of mating among mating seasons might explain this apparent recognition of offsprings’ paternity. Fathers, for example, might regularly associate with young who maintain a close relationship with females with whom they have previously mated, and mothers might selectively permit juveniles who maintain a close relationship with males with whom they have previously mated to associate with their infants. This hypothesis is tested in this paper by comparing the observed distribution of 70 maternal sibships, members of which were fathered by the same or by different adult males over a 4-year period in six captive groups of rhesus monkeys, with that distribution expected based on random mating from season to season. Seasonal mating patterns were found to be random. Preparations are now underway to test this hypothesis in several free-ranging groups.     

Cellular aspects of pathogenesis of hypertrophic cardiomyopathy: Role of cardiomyocyte polyploidy and activation of nuclear antigen of the proliferating cell in myocardium

For a comparative analysis of cytomorphological characteristics of hypertrophied interventricular septum (IVS), both patients different ages with severe courses of obstructive hypertrophic cardiomyopathy (OHCMP) were examined, including children, and patients with essential arterial hypertension (EAH). The course of OHCMP in children as compared with adults was found to be characterized by considerable IVS hypertrophy that was accompanied by an acceleration of cardiomyocyte polyploidization. The mean ploidy level of cardiomyocytes in children with OHCMP was higher than in adult patients. The mean ploidy level of nuclei, the number of prolipherative cell nuclear antigen (PCNA)-positive nuclei, and the number of polyploid cardiomyocyte nuclei in adult patients with OHCMP were significantly higher statistically than in patients with EAH. The PCNA-positive labels in stromal cells were revealed only in patients with OHCMP. The obtained data indicate an important role of cardiomyocyte polyploidy and of activation of the proliferating cell nuclear antigen in development of myocardial hypertrophy in patients with OHCMP.     

Evaluation of the role of angiogenic factors in the pathogenesis of schistosomiasis

Schistosomiasis is one disease produced by helminths, which affect many people in tropical areas. Granuloma formation is the main mechanism involved in the pathogenesis of this disease. Experimental studies have demonstrated angiogenesis (blood vessels formation from pre-existing vessels) in the initial phase of granuloma formation. In the present work, VEGF (vascular endothelial growth factor) levels were analyzed in sera from people diagnosed with different helminthic infections. Patients with schistosomiasis and filariasis had significantly high VEGF levels in compared with healthy people and patients diagnosed with hookworms. In addition, the effects of angiogenesis inhibition using anti-angiogenic factors (endostatin) were evaluated in a schistosomiasis murine model. A lesion decrease was observed in mice infected with Schistosoma mansoni and treated with endostatin. Finally, mechanisms of angiogenesis induction were studied and observed that cercariae antigens stimulated the angiogenic factors by host alveolar macrophages.     

The importance of microscopic examination in the management of desquamative diseases of the scalp

After determining the usual malassezic biota of the scalp in adult, normal persons, 259 patients with different desquamative diseases were studied by a simple adhesive tape technique. The main purpose of this study was to investigate the utility of this technique to improve the diagnosis and treatment of patients. Most patients with seborrhoeic dermatitis and sebopsoriasis demonstrated large numbers of {it Malassezia} spp. cells corresponding to the so called ``pityrosporosis'. Only 43.6% of patients with pityriasis capitis (dandruff) presented with such a diagnosis. Symptomatic pityrosporosis of the scalp should be treated with imidazolic derivatives or other antifungal substances. Patients with psoriasis of the scalp showed a typical microscopic picture represented by parakeratosic (nucleated) keratinocytes with absence of lipophilic yeasts which should be attributed to the usual dryness of the scales .Microbial epidermitis (eczema) of the scalp revealed another characteristic picture constituted by abundant leukocytes and bacteria without the presence of yeasts. The different microscopic pictures seen with this simple technique for diseases of the scalp, offer an adjunct to make a proper diagnosis and to establish a convenient treatment in cases which are not clinically well defined. This revised version was published online in June 2006 with corrections to the Cover Date.     

36例妊娠性急性脂肪肝救治方法分析

目的探讨妊娠急性脂肪肝（acute fatty liver of pregnancy,AFLP）的有效治疗方法。方法回顾性分析36例AFIP的治疗方法,其中31例妊娠急性脂肪肝,首选剖宫产术终止妊娠,其次考虑阴道分娩。5例患者因为发生肝功能衰竭而采用MARS联合血浆置换治疗。结果31例的患者获得了良好的预后,尤其是5例AFLP肝功能衰竭患者均采用人工肝血浆置换疗法,均获痊愈。结论妊娠急性脂肪肝通过治疗,能获得良好的预后。