不同覆土基质微生物结构特征研究及其对双孢蘑菇产量的影响

覆土是影响双孢蘑菇产量、质量和出菇整齐度的重要因子,利用现代分子生态学的方法快速、准确地对不同覆土基质微生物结构特征进行检测,以进一步了解微生物群落与双孢蘑菇相互作用关系。测定了不同覆土的理化特性,应用PCR技术对不同覆土材料提取总DNA,扩增细菌16S rDNA和真菌28S rDNA,运用变性梯度凝胶电泳技术对PCR产物进行分析,研究双孢蘑菇不同覆土基质微生物结构特征。结果表明：不同处理的覆土材料微生物群落的基因具有多样性,其中细菌群落基因多样性存在差异,使用纯泥炭与粉碎稻草处理差异最大,相似性仅为62%;通过真菌28S rDNA变性梯度凝胶电泳结果显示,粉碎稻草处理多样性指数最高,达3.576,但随着泥炭比例的提高,覆土处理中真菌群落的多样性相对减少;栽培试验发现,双孢蘑菇子实体形成量、总产量可能与覆土中的真菌群落多样性呈负相关。     

不同地区双孢蘑菇中蘑菇氨酸含量的比较研究

蘑菇氨酸曾被怀疑具有潜在的致癌效应,但其生理作用目前还存在争议.为比较分析我国不同地区双孢蘑菇中蘑菇氨酸含量,本研究采用反相高效液相色谱法检测了我国5个双孢蘑菇产区30份新鲜双孢蘑菇样品中蘑菇氨酸的含量.结果显示,我国双孢蘑菇中蘑菇氨酸含量范围较广,为155.6～934.4mg/kg FW.在此基础上,分析了菌株类型、培养料类型和采收季节等因素对蘑菇氨酸含量的影响.结果表明,不同菌株、不同栽培条件下生产的双孢蘑菇中蘑菇氨酸的含量差异明显.     

双孢蘑菇及大肥菇的种内及种间多态性RAPD分析*

应用RAPD方法分析双孢蘑菇（Agaricusbisporus）及大肥菇（Agaricusbitorquis）的种内及种间多态性,进一步证实由于双孢蘑菇的遗传保守性,多数孢子为自体可育的异核孢子,从而导致种内相似性很高;而依赖天然杂交具四孢特性的大肥菇种内相似程度较低。研究还分析评价了蘑菇属中的这两个不同种之间的亲缘关系,为种间杂交选材提供了理论依据。     

双孢蘑菇对高温胁迫的响应及耐热机理

本研究以双孢蘑菇Agaricus bisporus工厂化菌株A15和筛选得到的耐高温菌株A15-TH为研究对象,比较了高温胁迫对两个菌株菌丝生长的影响,并从氧化损伤修复及基础碳代谢-糖酵解途径两个角度探索双孢蘑菇对高温胁迫的响应及耐热机理.高温胁迫下,对照菌株A15的菌丝生长速度降低,菌丝分叉增加;而耐高温菌株A15-...     

双孢蘑菇疣孢霉病的发病过程及病原菌的核相研究

【目的】确定有害疣孢霉的传播途径,明确双孢蘑菇受有害疣孢霉侵染后发病症状和微观形态变化,以及有害疣孢霉的核相。【方法】将有害疣孢霉喷施于培养料及覆土材料的不同深度,观察记录双孢蘑菇的发病情况;将有害疣孢霉接种于不同生长阶段的双孢蘑菇子实体,观察记录其发病情况;使用光学显微镜及扫描电镜观察双孢蘑菇子实体受有害疣孢霉侵染前后的形态变化;通过DAPI(4′,6-二脒基-2-苯基吲哚)染色的方法对有害疣孢霉核相进行观察。【结果】将有害疣孢霉接种于培养料及覆土层的不同深度得到双孢蘑菇发病率如下:覆土层表面覆土层中间覆土与培养料交界处培养料中间层;有害疣孢霉可以侵染双孢蘑菇的任意阶段,将其接种于原基直径小于3 mm子实体表面时,得到不能正常分化的"马勃状"组织;对有害疣孢霉的侵染过程进行观察得到:其孢子可粘附于双孢蘑菇表面,并萌发长出芽管,接种处双孢蘑菇表面产生褐色病斑,双孢蘑菇菌丝体发生质壁分离,最后菌丝体膨大,细胞壁变薄甚至溢裂,菌丝体内部中空;有害疣孢霉产生两种类型的分生孢子,Ⅰ类无隔膜含1个细胞核;Ⅱ类具1隔膜含2个细胞核,2个细胞核被隔膜分开;细胞核的第1次有丝分裂发生于分生孢子母细胞中;厚垣孢子由上下2个细胞构成,上胞中含有2个细胞核。下胞含1–2个细胞核。有害疣孢霉的厚垣孢子萌发可产生1–2个芽管,芽管中细胞核的数目不断变化,一般0–2个细胞核。【结论】双孢蘑菇受其侵染后发生显著的细胞学变化;我们对有害疣孢霉做遗传分析时,进行单孢分离需挑取无隔膜的分生孢子为实验材料进行遗传分析。     

双孢蘑菇子实体发育不同阶段蛋白质组分析

为探讨双孢蘑菇子实体发育不同阶段的蛋白质表达变化,对双孢蘑菇As2796菌株子实体原基期、幼菇期、采收期、开伞期的蛋白质组进行了二维液相色谱串联质谱（iTRAQ-MS/MS）分析,共获得不同肽段5 869个,鉴定到1 059个蛋白质,其中1 007个具有相对定量信息。与双孢蘑菇原基期相比,幼菇期、采收期和开伞期分别有差异蛋白质242、200、240个,分别占鉴定蛋白质总数的24.0%,19.9%和23.8%。对这些蛋白质及不同阶段之间的差异蛋白质进行了系列生物信息学分析,对8个上、下调表达具有连续性的差异蛋白质相关基因进行了荧光定量PCR验证,其中3个蛋白质（错配碱基识别蛋白、细胞色素C1及某推定的未知蛋白质）基因的转录与蛋白质的表达具有较为一致的趋势。这些结果为后续双孢蘑菇子实体发育相关基因的功能研究奠定了良好的基础。     

农杆菌介导双孢蘑菇AS2796转化体系的优化

双孢蘑菇Agaricus bisporus是一种药食皆宜的食用真菌,具有极高的经济价值,近年来在双孢蘑菇全基因组测序完成后,功能基因组学的研究逐步提上日程。其中,高效的遗传转化体系作为技术基础成为研究重点。农杆菌介导的遗传转化体系作为一种高效的功能基因组研究方法,在双孢蘑菇中已经得到了广泛的应用,但是仍然存在着效率较低的问题有待解决。为了提高双孢蘑菇的农杆菌转化效率,找到双孢蘑菇遗传转化的最优条件,本实验首先对双孢蘑菇的潮霉素抗性压力进行了筛选,结果显示20mg/L的潮霉素浓度可以抑制菌丝生长,而50mg/L的潮霉素浓度则可以完全抑制菌丝生长。其次,对农杆菌菌株、菌液浓度、乙酰丁香酮浓度、菌丝培养时间以及浸染时间做了L16（4 ⁵）的正交实验,通过对各因素影响的分析,得出对转化效率影响最大的因素为菌丝培养时间和农杆菌菌株,且当菌株为LBA4404、菌液浓度OD₆₀₀=0.8、乙酰丁香酮浓度为100μmol/L、菌丝培养时间为40d、浸染时间为10min时,农杆菌介导的双孢蘑菇遗传转化效率最高。     

双孢蘑菇‘福蘑58'的选育报告

双孢蘑菇‘福蘑58'是W2000单孢分离筛选的新品种。菌落形态为贴生型,菌丝在10-32℃下均能生长,最适生长温度24-28℃。结菇温度10-22℃,最适结菇温度14-20℃。子实体单生为主,丛生少,较结实,不易开伞,菌盖扁半球形,表面光滑,颜色较白,直径3.5-5.0cm,高度2.4-2.8cm。在适宜栽培条件下,平均单产比亲本菌株W2000提高10%-15%,鲜菇质量与W2000相当,比W192提升明显,成品菇比例较高,品质优良,适合鲜销市场及罐头加工。该品种可用于周年工厂化、设施化及季节性农法栽培。     

有害疣孢霉菌与双孢蘑菇的互作关系

通过菌丝对峙、双重培养,以及对发病双孢蘑菇子实体的显微观察,探讨有害疣孢霉菌Mycogone perniciosa（MP0012）与双孢蘑菇Agaricus bisporus（As2796）之间的互作关系。结果表明,在菌丝对峙生长阶段有害疣孢霉菌菌丝不侵入双孢蘑菇菌丝体内,两者可交叉生长,对双孢蘑菇生长影响不显著;对峙与双重培养均显示有害疣孢霉菌菌丝会产生对双孢蘑菇菌丝生长的抑制作用的挥发性物质,造成双孢蘑菇菌丝扭结断裂。同时试验证实了双孢蘑菇菌丝会促进有害疣孢霉菌厚垣孢子的产生和萌发、菌丝生长和发育。侵染实验结果表明,有害疣孢霉菌可直接侵染双孢蘑菇子实体,引起双孢蘑菇子实体病害;对罹病子实体显微观察结果发现,发病前期双孢蘑菇子实体表面长出绒毛状病原菌丝,菌柄中空,菌褶褐变腐烂并长出病原菌丝;发病中期双孢蘑菇子实体内菌丝组织会出现萎缩裂解现象,在近有害疣孢霉菌菌丝一侧的双孢蘑菇子实体菌丝细胞壁被降解;发病后期双孢蘑菇子实体菌丝组织基本消失。由此初步判断有害疣孢霉菌对双孢蘑菇的寄生类型偏向于死体营养型。     

湖北省双孢蘑菇子实体中重金属铅镉含量及来源分析

双孢蘑菇Agaricus bisporus子实体中重金属铅、镉含量分析结果表明,铅、镉的背景值含量分别为0.636mg/kg和0.127mg/kg,样品中铅含量的范围为0.087－2.40mg/kg,镉含量的范围为0.038－0.301mg/kg。在两种不同栽培模式下,子实体中铅含量均有显著差异,但镉的含量并无显著差异。相关性分析表明,子实体中铅来源于覆土而与培养料无关,而镉的来源与栽培方式有关,覆土和培养料中的镉含量均影响子实体中的镉含量。     

Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP)¹. The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments.     

鸡腿菇研究进展

鸡腿菇(Coprinus comatus),学名毛头鬼伞,是近年来发展较快的一种药食兼用的食用菌。结合实验室研究成果,从生物学特性、病虫害、分类和药用价值等方面详细阐述了国内对外鸡腿菇的研究进展。     

Properties of peat-based casing soils and their influence on the water relations and growth of the mushroom (Agaricus bisporus)

Different combinations of peat and chalk or lime sources with differing moisture contents were used to determine how specific physical and chemical properties of the casing soil relate to the growth and water relations of the mushroom. The peat types varied in terms of decomposition and extraction method; the lime addition varied in terms of rate and type (chalk or sugar beet lime). During the colonisation of the casing soil before fruiting, the extension growth rate of mushroom mycelium was most closely correlated (negatively) with the volumetric moisture content of the casing soil. Scanning electron microscopy showed that mycelium growing at a lower casing soil matric potential (Ψ_m) had a much finer and branched structure than mycelium growing at a higher Ψ_m. Across all the peat and lime source treatments, a relationship was found between the mean Ψ_m of the casing soil and mushroom yield, with an optimum Ψ_m of -7.9 to -9.4 kPa. Mushrooms are produced in ‘flushes’ at about 8-day intervals and during the development of each flush of mushrooms, there was a significant decrease in casing soil Ψ_m . This decrease (to below -40 kPa) was greatest in the second flush, which was the highest yielding. There were no relationships between mushroom yield and casing soil osmotic potential Ψ_π within the range -93 to -154 kPa or any of the other chemical properties and water and air holding characteristics of the casing soils which were determined. Across different casing soil treatments, mushroom dry matter content was negatively correlated with mushroom yield and positively correlated with mushroom tissue osmotic potential. This revised version was published online in June 2006 with corrections to the Cover Date.     

Influences of compost and casing layer depths on the mechanical properties of mushrooms

The mushroom growing bed consists of an underlying compost which is covered with casing (a peat and chalk or lime mixture) to induce fruit-body formation. The influences of the depths of the compost and casing layers on the mushroom texture, susceptibility to bruising, and ease of detachment from the growing bed surface were investigated. Textural properties were determined on cubes of cap tissue and detachment torque was determined by using an instrumented rotating suction cup which was lowered on to the caps. The proportion of mushrooms which detached at the base from the bed surface was recorded, since this is an important parameter for an automatic (robotic) harvesting system. Shallow casing resulted in mushrooms that were firmer and less likely to deform plastically, but that showed greater discolouration after a standard bruising treatment. Shallower casing also increased the proportion of mushrooms that detached at the base. Increasing the depth of compost produced firmer mushrooms, significantly increased the detachment torque and reduced the proportion of mushrooms detached at the base. The proportion of mushrooms that detached at the base correlated negatively with the plastic deformation of cap tissue. A positive correlation was found between mushroom dry matter content and tissue firmness.     

卵孢小奥德蘑覆土真菌群落特征及其影响因素

卵孢小奥德蘑Oudemansiella raphanipes是一类依赖覆土栽培的食用菌。本文采用Illumina MiSeq高通量测序技术结合生态学及统计学分析方法研究卵孢小奥德蘑覆土真菌群落特征和影响因素。结果表明,与原始覆土内真菌群落相比,种植卵孢小奥德蘑后的覆土内真菌群落多样性显著下降;在组成方面,虽然优势菌门仍为子囊菌门Ascomycota,但其中的Cladosporium、Acremonium、Gibberella和Emericellopsis等属的相对丰度有所降低,而隶属于被孢霉门Mortierellomycota的Stilbella、Neocosmospora、Pseudogymnoascus和Preussia等属的相对丰度呈增加趋势。卵孢小奥德蘑覆土真菌以腐生营养型为主,与原始覆土相比,种植卵孢小奥德蘑后的粪生营养型真菌和木腐菌呈增加的趋势;进一步研究发现pH、速效钾、速效磷和总氮等覆土土壤理化性质显著影响真菌群落的多样性和结构,pH和速效钾含量与真菌群落的丰富度和多样性呈显著负相关关系。研究结果为深入解析卵孢小奥德蘑覆土微生态机制奠定基础。     

Current challenges in understanding melanogenesis: bridging chemistry,biological control,morphology, and function

Melanin is a natural pigment produced within organelles, melanosomes, located in melanocytes. Biological functions of melanosomes are often attributed to the unique chemical properties of the melanins they contain; however, the molecular structure of melanins, the mechanism by which the pigment is produced, and how the pigment is organized within the melanosome remains to be fully understood. In this review, we examine the current understanding of the initial chemical steps in the melanogenesis. Most natural melanins are mixtures of eumelanin and pheomelanin, and so after presenting the current understanding of the individual pigments, we focus on the mixed melanin systems, with a critical eye towards understanding how studies on individual melanin do and do not provide insight in the molecular aspects of their structures. We conclude the review with a discussion of important issues that must be addressed in future research efforts to more fully understand the relationship between molecular and functional properties of this important class of natural pigments.     

A novel multiple membrane blood‐feeding system for investigating and maintaining Aedes aegypti and Aedes albopictus mosquitoes

A novel multiple membrane blood‐feeding system for mosquitoes has been developed for the study and routine maintenance of Aedes aegypti L. and Aedes albopictus Skuse that require a meal of vertebrate blood to produce eggs. This blood‐feeding system uses cattle collagen sausage‐casing membrane to facilitate feeding. The efficiency of this blood‐feeding system was compared to a live mice blood source. We observed that Ae. aegypti that fed on pig whole blood had 89.7% (w/o ATP) and 90.7% (w/ ATP) blood‐feeding rates, which were not significantly different from the mice‐fed ones (98.0%). Ae. albopictus fed on pig whole blood (w/ ATP) had a success rate of 84.4%, which was significantly different from the mice‐fed mosquitoes (51.1%). The feeding rates did not differ between sausage‐casing membrane and Parafilm‐M®. The survival rate, fecundity, pupation, and pupal emergence rates of Aedes females fed on pig whole blood were not significantly different from the mice‐fed ones. The artificial blood feeder can be applied to replace live animals as blood sources. Considering that this simple, inexpensive, convenient, and efficient feeding device can be built with common laboratory materials for research on Aedes mosquitoes.     

Substrate dependent larval development and emergence of the mushroom pests Lycoriella auripila and Megaselia halterata

Pasteurized, spawned, full-grown and immediately-cased full-grown compost were simultaneously exposed to natural populations of the mushroom pests Lycoriella auripila (Winnertz) (Diptera: Sciaridae) and Megaselia halterata (Wood) (Diptera: Phoridae). Different numbers of adults emerged from each of these composts. Highest numbers of L. auripila emerged from spawned and pasteurized compost whereas lowest numbers of L. auripila emerged from full-grown compost. the emergence from full-grown compost was delayed, which could be explained by the delayed development of the larvae in this type of compost. High numbers of M. halterata emerged from compost that was completely colonized by the mycelia of the edible white button mushroom Agaricus bisporus (Lange) Imbach. The immediate covering of the compost with a casing layer significantly lowered the numbers of emerging M. halterata flies. Compared with the emergence pattern from full-grown and immediately-cased full-grown compost, adult M. halterata showed a delayed pattern of emergence in spawned compost. Adult M. halterata did not emerge from pasteurized compost. The results of these experiments enabled us to improve the timing of the application of insect pathogenic nematodes in the control of the larvae of both insect pests.     

多级溶媒回流提取制备烟用香料酸角浸膏的研究

研究了多级溶媒提取酸角浸膏,分析了酸角浸膏的主要成分,并进行了卷烟加料试验.加料实验表明卷烟的烟气柔和细腻、香气量增加、刺激降低口感改善;低沸点部分挥发性成分种类和含量明显增加,酒石酸和还原糖含量明显较高,而蛋白质和果胶含量明显较低.