Comparison of plant and fungal gravitropic responses using imitational modelling

The mechanisms of gravity perception are still hypothetical, but there are sufficient data from experiments with plants to enable mathematical modelling to imitate the behaviour of gravitropic response systems. We have a much less complete picture of gravitropic kinetics in agaric mushrooms. However, some existing mathematical models which imitate plant responses are in principle universal because their conceptual components are not limited to any specific cellular entities. In this work we have used such models to compare plant and fungal gravitropism, using recently acquired kinetic data from the agarics Coprinus cinereius and Flammulina velutipes. The results show striking similarities between plants and fungi. First, it is evident that the basic assumptions of the plant models are logically applicable to fungi. Secondly, the mechanism of bending is the same (differential growth of opposite flanks of the growing organ). Thirdly, the distribution of growth seems very similar: in both plants and fungi growth of the organ is most intensive just behind the apex and is almost absent at the apex and at the base. Fourthly, in both fungi and plants the gravitropic response exhibits a substantial time delay suggesting that many time-consuming processes are involved in reception, transduction and realization of gravitropic stimuli. Important differences in plant and fungal gravitropism kinetics were: (i) the agaric stem apex always returned to the vertical, whereas some plant organs show stable plagiogravitropic growth; (ii) inflections were usually seen in C. cinereus stem gravitropism time courses suggesting that a curvature compensation process delayed bending for a time; (iii) C. cinercus stems very rarely overshot or oscillated around the vertical although many plant subjects oscillate and the (limited) data for F. velutipes showed a single, exaggerated overshoot and oscillation. In this latter case, experimental modelling with parameters characteristic of a low level of perception improved the fit to the F. velutipes data, indicating that the two fungi may differ in this factor. Application of the plant models focused future research attention on the urgent need for data bearing on angle-response and acceleration–response relationships in fungi, and their detection–level thresholds for gravitational acceleration. Since the modelling also highlighted some fundamental kinetic differences between the only two fungi for which sufficient data are available at the moment, it is also clear that detailed observations need to be made of gravitropism kinetics in a larger number and wider range of fungi.     

火菇素蛋白的免疫印迹检测*

从金针菇子实体浸提液中提取了抗癌活性物质火菇素,将纯化的火菇素用Freund佐剂乳化后注射到新西兰白兔体内,经数次加强免疫后采血并分离了抗血清,并以抗血清为探针建立了火菇素蛋白的免疫印迹法定性检测方法。应用免疫学方法检测金针菇菌丝体和子实体,结果显示,只在金针菇子实体中发现与火菇素抗体相结合的抗原信号。     

A possible role of the key enzymes of the glyoxylate and gluconeogenesis pathways for fruit-body formation of the wood-rotting basidiomycete Flammulina velutipes

 Biochemical roles of the representative enzymes involved in carbon metabolism of glucose were investigated in relation to the fruit-body formation of the basidiomycete Flammulina velutipes. Changes in specific activities of the enzymes of the tricarboxylic acid (TCA) cycle and glyoxylate (GLOX) and gluconeogenesis pathways were measured at different stages of development of the fungus. The enzyme activities of malate synthase (MS) and fructose bisphosphatase (FBP) as the key enzymes for the GLOX-gluconeogenesis pathways increased in mycelia during the fruit-body formation. The activities of isocitrate dehydrogenase (IDH) for the TCA cycle and NADP-linked glutamate dehydrogenase (GLTDH (NADP)) for glutamate synthesis increased more markedly. Moreover, the mycelial mat of the cultures producing fruit bodies yielded greater enzyme activities of isocitrate lyase (ICL), MS, FBP, and IDH than that of the cultures that did not produce fruit bodies. These results suggest that the GLOX-gluconeogenesis pathways as well as the glutamate synthesis have a strong correlation with the fruit-body formation of F. velutipes. Received: January 22, 2002 / Accepted: May 10, 2002     

金针菇基因组测序与组装策略分析

采用二代和三代测序技术分别对金针菇单核体菌株“6-3”进行测序,应用4种组装策略进行基因组的de novo组装,对比组装效果。基因组组装的参数方面,仅使用二代测序组装的效果最差,长度大于10kb的Contig全长只有24.6Mb,Contig N50只有23kb,组装率只有59.27%。采用三代组装二代校正的组装策略效果最好,长度大于10kb的Contig全长为38.3Mb,Contig N50为2.8Mb,组装率高达92.16%。保守单拷贝基因拼接效果方面,4种组装策略获得基因组序列与BUSCO数据库里的担子菌的保守单拷贝基因比对,基因完整性均大于94%。在组装准确性方面,经过PCR扩增、Sanger测序验证,三代组装二代校正的基因组序列完整并且连续,同时序列上碱基的SNP、InDel数量最少。综上所述,三代组装二代校正得到的基因组序列具有Contig N50值大、组装率高、碱基准确性高的特点,是食用菌基因组测序较为理想的方案。     

金针菇子实体有机溶剂提取物的生物活性

分别对金针菇子实体醇提物的5个萃取分部（石油醚、氯仿、乙酸乙酯、正丁醇分部和剩余分部）进行化学成分的定性检验,以及体外抗肿瘤活性和降血糖活性的筛选。定性检验结果表明,金针菇子实体的石油醚、氯仿和乙酸乙酯萃取分部中含有生物碱类、有机酸类、甾类（或三萜）、黄酮类和蒽醌类物质,正丁醇萃取分部中含有氨基酸和蛋白类、糖类、甾类（或三萜）、有机酸类和黄酮类物质,剩余分部中含有氨基酸和蛋白类、糖类、甾类（或三萜）化合物。通过药理筛选发现,金针菇子实体的石油醚、正丁醇以及剩余分部具有体外抗肿瘤作用的潜力,而氯仿和乙酸乙酯分部则具有一定的细胞毒性;各萃取分部对DPP-IV活性均具有一定的抑制作用,其中氯仿和乙酸乙酯分部的抑制作用较强。     

金针菇功能性蛋白的研究进展

主要综述了近年关于金针菇功能性蛋白,即核糖体失活蛋白、真菌免疫调节蛋白、金针菇毒素(一种成孔溶细胞素)的分离纯化及其性质,它们的生物学作用与作用机制和它们可能的应用及展望。     

金针菇固体发酵菌丝体次级代谢产物分离鉴定

采用硅胶柱色谱、ODS柱色谱、Sephadex LH-20柱色谱、HPLC等分离方法对金针菇大米发酵乙酸乙酯提取物进行分离,根据理化性质和波谱数据鉴定化合物结构：鉴定了4个倍半萜,包括1个新的桉叶烷型倍半萜,3个侧柏烷型倍半萜,分别是flamvelutpenol A(1),aquaticol(2),enokipodin C(3),limacellone(4)。并通过与Rh2(OCOCF3)4络合的方法确定了新化合物flamvelutpenol A(1)和limacellone(4)的绝对构型。其中化合物3具有较好的抗菌活性,对耐甲氧西林金黄色葡萄球菌和枯草芽孢杆菌的MIC值分别为12.5mg/L,25mg/L。且化合物1－4均是首次从该种真菌中分离得到。     

金针菇菇脚对肉鸡肠道菌群的影响

目的 研究金针菇菇脚（Flammulina velutipes stembase,FVS）对肉鸡生长性能、肠道发育及肠道菌群的影响。方法 选取4 550只1日龄爱拔益加（AA）肉鸡,随机分为5组：空白组（基础日粮）、2% FVS组（基础日粮+2% FVS）、4% FVS组（基础日粮+4% FVS）、6% FVS组（基础日粮+6% FVS）和6% FVS阶段组（基础日粮+试验第1、3、5周饲喂含有6%FVS的日粮,于试验2、4、6周饲喂基础日粮）。试验为期42 d。结果 FVS组肉鸡平均日增重量均显著高于空白组（P<0.05）。6% FVS组和6% FVS阶段组肉鸡平均日采食量显著高于空白组（P<0.05）。FVS组肉鸡料重比均显著低于空白组（P<0.05）。与空白组相比,日龄21 d时,2% FVS组肉鸡回肠和盲肠重量均显著增加（P<0.05）;4% FVS组十二指肠长度和盲肠重量均显著增加（P<0.05）;6% FVS阶段组十二指肠长度及重量、空肠长度及重量和回肠重量均显著增加（P<0.05）。与空白组相比,日龄42 d时,2% FVS组肉鸡十二指肠长度和重量及盲肠重量均显著增加（P<0.05）;4% FVS组十二指肠长度和重量、回肠长度和盲肠长度及重量均显著增加（P<0.05）;6% FVS组十二指肠长度和盲肠长度及重量均显著增加（P<0.05）;6% FVS阶段组十二指肠重量、空肠重量和回肠长度及重量均显著增加（P<0.05）。与空白组相比,日龄21 d时6% FVS阶段组肉鸡盲肠菌群DNA条带数显著增加;日龄42 d时FVS组肉鸡盲肠菌群DNA条带数均显著增加。日龄21 d和42 d时肉鸡盲肠菌群共性条带中均含有扭链胃球菌（Ruminococcus torques）,而FVS组含有大量的产酸菌。结论 日粮中添加FVS可提高肉鸡生长能力、促进肠道发育、增加肠道菌群多样性。     

Alterations in the composition of membrane glycero-and sphingolipids in the course of <Emphasis Type="Italic">Flammulina velutipes</Emphasis> surface culture development

Qualitative and quantitative characteristics of the alterations in the lipid composition of the membrane of the basidial fungus Flammulina velutipes in the course of surface culture development were investigated. Modifications of the lipid composition were shown to be timed to specific ontogeny stages, such as changes in the growth rate of the colonies, the appearance of differentiated vegetative cells, and the formation of generative structures. A slowdown of growth correlated with an alteration in the ratio of major classes of phospholipids, namely, with a decrease of phosphatidylcholine relative content and an increase in phosphatidylethanolamines. The differentiation of vegetative cells of the mycelium proceeded along with modifications of molecular composition of glycoceramides. In the course of the first week of growth, the surface culture of F. velutipes produced monohexosylceramides with epoxidized methyl sphingadienine as a sphingoid base. Later on, along with culture growth and specialization of mycelium cells, molecular species with methyl sphingadienine, common for basidiomycetes, start to prevail among the fungal glycoceramides. The formation of fruit bodies is accompanied by enrichment of molecules of phospholipids, mainly, the phosphatidylcholines, with unsaturated fatty acids.     

金针菇粉孢子的生物学研究

采用单孢分离的方法分离培养金针菇粉孢子,对粉孢子的产生、萌发、核相及极性进行了研究。结果表明：单核菌丝和双核菌丝都产生粉孢子,粉孢子多呈圆柱或卵圆形,少数呈圆形或Y形。粉孢子很容易萌发,其芽管直径一般较粉孢子宽。单核菌丝产生单核的粉孢子,其极性与亲本菌丝相同;双核菌丝产生的粉孢子也为单核,未观察到双核或多核的粉孢子。双核菌丝产生的粉孢子一部分与组成双核体的一个亲本单核菌丝的交配型相同,另一部分与组成双核体的另一亲本单核菌丝有相同的交配型。