蜜环菌对镁的耐性和富集特性

研究了镁对蜜环菌生长的影响, 蜜环菌对于镁的耐性和富集规律, 以及高浓度镁胁迫下蜜环菌的抗氧化酶的变化情况。3?15 g/L的Mg浓度对于蜜环菌菌体的生长有促进作用。Mg浓度19 g/L以上时, 蜜环菌菌体的生长受到抑制。蜜环菌的子实体形成和子实体生物量在Mg的浓度为11 g/L以下时不受影响, 超过11 g/L则子实体不能萌发。皮壳状菌丝和菌索中Mg的含量随培养基中Mg浓度的增大而增大, 培养基Mg浓度达到16 g/L后, 菌丝、菌索中Mg的含量都不再上升。子实体对Mg的富集量比菌丝体小的多, 在培养基Mg浓度在9、10 g/L时, 子实体中Mg的含量与对照组有显著差异。随着培养基中Mg浓度的提高, 菌丝和菌索POD、CAT、SOD活性都有增加, 而且菌丝与菌索之间抗氧化酶活力的差异随着培养基中Mg浓度的提高而增大。     

蛹虫草对锌的耐性与富集特征

在培养基内添加不同量的锌,研究其对蛹虫草子实体的形成、子实体和菌丝体生物量、子实体多糖含量和葡萄糖含量的影响,以及蛹虫草子实体和菌丝体对锌的富集能力。结果表明锌对上述各项都有影响。液体培养条件下,锌浓度在453906mg/L范围内可以促进菌丝体生长,锌浓度超过4077mg/L时,菌丝生长受到抑制。培养基锌的浓度在4077mg/L以下时,蛹虫草菌丝体锌的富集量随着液体培养基锌浓度的提高而提高。固体培养条件下,锌含量在226453mg/kg范围内可以促进蛹虫草子实体生长,并且在此含量范围内,蛹虫草子实体中葡萄糖含量较高。培养基锌含量在680906mg/kg时,子实体多糖含量较高。培养基锌含量在2038mg/kg以下时,蛹虫草子实体中锌的富集量随着培养基锌含量的提高而提高,在培养基锌含量为2038mg/kg时,子实体中锌的含量达到28570mg/kg(干重)。     

蜜环菌菌索形成及分支过程中钙离子流的非损伤微测

为研究蜜环菌Armillaria mellea菌索形成及分支与钙离子的关系,以菌株Armillaria mellea 541为试验材料,采用离子非损伤微测技术,对在马铃薯琼脂糖培养基(PDA)、含0.2 g/L CaCl_2的PDA和NADPH氧化酶抑制剂200μmol/L氯化二亚苯基碘鎓(Diphenyleneiodonium chloride,DPI) PDA上培养的蜜环菌菌丝及菌索顶点、菌索分支点和成熟菌索与微环境间钙离子流进行测试。结果表明:菌株A. mellea 541菌丝和菌索的生长及菌索分支均与钙离子相关。添加0.02%CaCl_2或200μmol/L DPI后,菌丝及菌索生长速度均加快,菌丝及菌索顶端钙离子内流; 0.2 g/L CaCl_2能够促进菌株A. mellea 541菌索的形成和侧向分支,菌索数量和分支数量均显著增加,成熟菌索及菌索分支处均外排钙离子; 200μmol/L DPI则抑制菌索形成及侧向分支过程。推测钙离子与活性氧可能协同调节菌索分支。试验结果为深入揭示蜜环菌菌索形成及分支的机制提供了数据支持和研究方向。     

蜜环菌多糖的生物合成与发酵条件的相关性

培养基的碳、氮源,ＰＨ值直接影响蜜环菌多糖的生物合成,泥炭水解液的添加量占培养基的１０％～３９％（Ｖ／Ｖ）时,对蜜环菌多糖的生物合成有促进作用。液体振范培养时,蜜环菌生长形成球形菌丝体,菌丝生物量３．４５ｇ／Ｌ,菌丝多糖（精糖）得率为０．２８４％,而静置液体培养有利于菌索形成,菌素生物量１４．０５ｇ／Ｌ,菌索多糖（精糖）得率为０．５１５％,胞外多糖的得率分别为２９．４％和８．３％     

蜜环菌菌索分化的差异蛋白质组学研究

菌索是蜜环菌与宿主互作的组织结构,蜜环菌菌丝形成菌索的分子机制尚不清楚。本研究采用SWATH-MS^ALL非标记定量蛋白质组学技术,首次对Armillaria mellea菌丝形成菌索过程的蛋白质组学进行了系统研究。在蜜环菌菌丝和菌索中共鉴定蛋白1 724个（global FDR 1%）,定量蛋白1 179个。与菌丝相比,蜜环菌菌索差异表达蛋白640个（上调表达256个,下调表达384个）。差异表达蛋白GO注释结果表明,蜜环菌菌索分化的生物学过程较复杂,差异蛋白参与的主要生物学过程包括有机含氮化合物代谢、有机物生物合成、小分子代谢、氧化还原反应等。分子功能富集结果提示,电子转运活性的富集因子最高,而氧化还原反应的富集P值最显著,这与KEGG注释的氧化磷酸化代谢活跃的结果一致。进一步的推测分析表明,蜜环菌菌丝形成菌索可能是受到氧化应激所致,菌索的形成可能促使诸如硫氧还蛋白样等毒力蛋白和富马酸的合成和释放增多,抑制宿主免疫而有利于蜜环菌侵染和定植于宿主。因此,对差异蛋白质组的进一步研究和深入解析不仅有利于揭示蜜环菌菌索形成的蛋白分子机制,同时也具有较强的理论和现实意义。     

北方蜜环菌菌索生长、发育对环境氧气及土壤湿度的响应

蜜环菌属Armillaria spp.真菌是重要的植物病原菌和兰科Orchidaceae植物天麻Gastrodia elata的专性共生菌,能以菌索形式在土壤中存活和传播,因此,土壤环境变化对蜜环菌菌索生长、发育的影响,是关系天麻栽培和森林蜜环菌病害的重要过程。为了揭示蜜环菌生长发育对土壤水分和氧气的适应特征,本研究以北方蜜环菌Armillaria borealis为研究材料,设计氧气浓度5%、15%、20%和30%的4个水平与土壤湿度20%、40%、60%和80%的双因素实验,在室内24 ℃及黑暗条件下培养,观察菌索发生时间(T)、测定菌索生物量(DW)、菌索长度(L)、菌索数(Nt)、菌索分枝数(Nf)和菌索直径(AD)。结果表明,土壤湿度和氧气浓度对北方蜜环菌菌索发育和生长具有显著影响,在15%的氧气浓度和60%的土壤湿度发育最快。本研究为人工模拟蜜环菌生长发育的环境提供了部分依据,对提高天麻人工栽培的产量,揭示森林蜜环菌病害发病机制具有重要价值。     

猪苓、伴生菌及蜜环菌共培养的形态学研究

本文对猪苓、伴生菌及蜜环菌两两共培养及三者共培养进行了宏观形态观察及细胞学水平上的研究。结果表明,猪苓与伴生菌共培养时,在二者之间形成一致密拮抗线,猪苓菌落表面菌丝分化产生大量菌丝束;猪苓与蜜环菌共培养时,猪苓能阻止蜜环菌菌索对其自身的进一步侵袭,互作区中的双方菌丝及菌索均停止生长;蜜环菌与伴生菌共培养时,蜜环菌能穿透整个伴生菌菌落,在伴生菌菌落下方产生大量分枝;三者共培养后,猪苓对蜜环菌的防御能力有所下降,伴生菌对蜜环菌的耐受力有所提高,蜜环菌产生的新分枝均向伴生菌一侧生长,猪苓与伴生菌之间并不形成致密拮抗线,只可见双方菌丝的白色交融区。 猪苓与伴生菌均能在蜜环菌菌索皮层上形成侵入位点。     

蜜环菌菌索生物学特性的研究

为提高榛蘑人工栽培中出菇的稳定性,对蜜环菌菌索的生物学特性进行了研究,通过在不同生长时间、环境温度、培养基质的条件下对蜜环菌菌索进行培养。试验发现,菌索会由具有活性的黄色菌索逐渐角质化变成黑色丝状菌索,为保持蜜环菌菌索的活性状态,最佳培养条件:培养时间应控制在15²3 d,最佳培养温度为恒温25℃,最佳培养基配方为PDA+麦麸+锯末。     

猪苓、伴生菌及蜜环菌共培养的形态学研究*

本文对猪苓、伴生菌及蜜环菌两两共培养及三者共培养进行了宏观形态观察及细胞学水平上的研究。结果表明,猪苓与伴生菌共培养时,在二者之间形成一致密拮抗线,猪苓菌落表面菌丝分化产生大量菌丝束;猪苓与蜜环菌共培养时,猪苓能阻止蜜环菌菌索对其自身的进一步侵袭,互作区中的双方菌丝及菌索均停止生长;蜜环菌与伴生菌共培养时,蜜环菌能穿透整个伴生菌菌落,在伴生菌菌落下方产生大量分枝;三者共培养后,猪苓对蜜环菌的防御能力有所下降,伴生菌对蜜环菌的耐受力有所提高,蜜环菌产生的新分枝均向伴生菌一侧生长,猪苓与伴生菌之间并不形成致密拮抗线,只可见双方菌丝的白色交融区。 猪苓与伴生菌均能在蜜环菌菌索皮层上形成侵入位点。     

琼脂固体培养基培养蜜环菌菌索总DNA的提取

野外采集的蜜环菌[Armillaria mellea(Vahl.ex Fr.)Quel]在提取DNA前需要分离获得纯化的菌丝体。常规液体培养获得菌丝团的方法感杂率较高,采集固体培养基表面cellophane膜上形成的菌丝则难以获得足量的DNA提取材料。蜜环菌细胞内含有大量多醣类物质,也使得蜜环菌高质量DNA的提取存在一定的困难。本研究通过改进试验,提供一个直接从琼脂固体培养基培养的蜜环菌菌索中提取高质量DNA的方法。其中样品的预先冻融处理方法可以促使蜜环菌菌索与琼脂分离;而在裂解提取缓冲液裂解材料细胞后加入1.25 mol/L KAc溶液,则有利于除去蜜环菌细胞内的多醣类物质以及残留的少量琼脂。通过琼脂糖电泳、紫外分光光度计对DNA浓度及OD值的测定、ISSR引物的PCR扩增以及酶切产物的PCR扩增等方法的检测,结果均表明该方法提取的DNA质量较好,符合进一步进行分子生物学研究的要求。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV