在早期生物学研究中,从真菌学家Panckow（1654）记录并描绘黏菌（粉瘤菌 Lycogala epidendrum）的第一篇文献开始,黏菌一度被认为是植物（de Tournefort 1700）、真菌（Micheli 1729）或海绵（Marchant 1727）。直至19世纪实验科学兴起,de Bary（1859,1884）对黏菌的结构和生活史进行了完整研究,为黏菌的“动物”特征提供了有力证据。黏菌具有复杂的生活史,包括了子实体、孢子、单细胞的黏变形体以及多核的原生质团等多个阶段。其中,原生质团是一种多核细胞（coenocytes,syncytium）,由原生质膜和胶质鞘包裹的无细胞壁的大型、无定形多核的原生质组成,细胞核可以进行连续的有丝分裂,但胞质没有分裂成单个细胞,形成了多核的变形体结构（Keller et al. 2017）。从依赖宏观特征差异到引入显微结构特征（Rostanfinsky 1874,1875,1876）,关于黏菌分类地位的争论直到20世纪末才基本解决。
随着1735年林奈的“自然系统”与1859年达尔文的“物种起源”的提出,现代生物学的研究从形态分类学向演化生物学逐步发展。伴随科学技术的飞速进步,黏菌类群在生物学及其交叉学科中成为了模式生物,在不同阶段的研究背景下提供重要的参考价值与科学意义。以多头绒泡菌Physarum polycephalum为代表的黏菌可以通过外部因素诱导完成生活周期,这是其他许多生物不能实现的,并且黏菌表现出许多后生动物典型的生化特征,使其成为研究真核生物细胞周期、细胞分化和发育的模型,是遗传学、生物发生学研究的重要实验材料（Clark 1984;Clark & Lott 1989）。黏菌的研究在20世纪70至80年代进入鼎盛时期,围绕着细胞分化和发育、细胞周期和运动3个主题展开了大量研究工作。此后,黏菌作为真核生物的“树冠”（Baldauf & Doolittle 1997）,对于理解真核细胞演化的多样性与同源性具有重要意义。
1 黏菌的分类与系统发育
黏菌是一类具有复杂子实体结构的原生生物。“Myxomycetes”最早被Link（1833）用于统称黏菌,其中“myxa”意为黏液,“mycetes”指菌物。尽管许多早期的研究者发表了对黏菌各属、种的鉴定描述,但de Bary（1859）认为相较于真菌,黏菌与阿米巴类的原生生物关系更为密切,并提议使用“Mycetozoa”作为黏菌类群统称,意为“真菌动物”。Rostafiński（1875）建立了第一个真黏菌分类系统,根据孢子颜色将真黏菌分为深色孢子和浅色孢子两个类群,即Amaurosporeae和Lamprosporeae,该分类系统在Lister（1894,1911,1925）和Hagelstein（1944）的补充下得到进一步完善,在Massee（1892）、Macbride（1922）、Jahn（1928）和Martin（1960）支持下,黏菌分类系统发展为5个目（即Echinosteliales,Liceales,Physarales,Stemonitales,Trichiales）。在相当长的一段时间内,黏菌的6目分类系统（包括Ceratiomyxales）获得了世界范围的认可（Martin & Alexopoulos 1969;Farr 1976;Nannenga-Bremekamp 1991;Neubert et al. 1993,1995,2000;Lado & Pando 1997;Yamamoto 1998;Ing 1999;Stephenson 2003;李玉等 2008;Poulain et al. 2011）。然而,由于Ceratiomyxales物种与其他5目物种存在明显的形态差异,在一些分类系统中,Ceratiomyxales被归于另一个类黏菌——原柄菌（Olive 1970,1975;Olive & Stoianovitch 1979）,按照近年的分子系统发育研究,更为合适的处理是将Ceratiomyxales作为其他黏菌的姐妹群（Fiore-Donno et al. 2005,2010;Shadwick et al. 2009）。
在黏菌纲内部,可以产生具有简单孢囊结构的Echinosteliales代表黏菌最基部的分支（Fiore-Donno et al. 2005）,并根据孢子颜色的差异进而聚集成两个分支,由Trichiales和Liceales组成浅色孢子分支,由Physarales和Stemonitales组成深色孢子分支（Fiore- Donno et al. 2005;Shadwick et al. 2009）。
在原生生物的系统发育研究中,Cavalier- Smith（2013）首次命名了内生孢子黏菌的两个基底进化枝,置于黏菌下纲Myxogastria的两个超目中,分别为Lucisporidia（浅色孢子黏菌）包括Liceales和Trichiales;Columellidia（深色孢子黏菌,通常具有囊轴）包括Echinosteliales,Physarales和Stemonitales,这种分类处理与Rostafiński（1875）的系统有很多共通之处。尽管在黏菌分类系统中原生质团的外观和子实体的发育在某种程度上也被考虑了（Ross 1973）,但分类系统更多地基于子实体的形态特征。假设每个分类单元都对应一个单独进化枝,Leontyev et al.（2019）将黏菌纲分为浅色和深色的进化枝,并命名为Lucisporomycetidae亚纲和Columellomycetidae亚纲;浅色黏菌包括4个目,分别为Cribrariales,Reticulariales,Liceales（狭义）和Trichiales;深色黏菌包括5个目,分别为Echinosteliales,Clastodermatales,Meridermatales,Stemonitidales（狭义）和Physarales（包括大多数具有持久囊被的传统Stemonitiales物种）;依据分子数据分析,认为孢丝和囊被的细节、连接结构更好地反映了系统发育关系。此系统区别于以往依据原生质团类型、子实体发育方式为基础的黏菌分类系统,在原生生物界的系统发育关系研究中,原生质团类型是高级分类单元重要的划分依据,传统的发网菌目中的部分黏菌是否应该划分至绒泡菌目可能还需补充更多的基因组数据加以分析。
2 黏菌细胞生物学
以多头绒泡菌为代表的黏菌常常被用于研究真核细胞和分子生物学的众多基础问题。其中,原生质团的同步有丝分裂与体细胞不兼容系统是黏菌细胞生物学研究中具有代表性的工作。
多头绒泡菌原生质团包含多达109个细胞核,每8-10h经历一次同步有丝分裂,因此,多头绒泡菌在20世纪70至80年代被广泛用于细胞周期事件的研究,成为研究癌症的理想生物（Rusch 1980）。在早期的研究中,认为黏菌原生质团的同步有丝分裂可能是细胞核的生物钟或细胞质因子导致的结果,这个问题直接关联了肿瘤细胞形成过程中失去细胞内部控制的细胞分裂现象。实验表明,同步有丝分裂的触发不在细胞核内,刺激物在细胞质内积累,并在有丝分裂发生前不久转移至细胞核（Cummins & Rusch 1968;Rusch 1970）。多头绒泡菌原生质团中的磷酸化活性在细胞周期中发生波动,可能是有丝分裂的触发因素（Bradbury et al. 1974）。此后,通过在不同阶段的原生质团的体细胞融合来控制周期的时间,黏菌的有丝分裂周期得以被详细描述（Rusch et al. 1966;Holt 1980;Wolf & Sauer 1982）。随后的研究证实,多头绒泡菌的细胞周期调控机制类似于大部分真核生物（Ducommun et al. 1990;Li et al. 2004;Schaap et al. 2016）。
黄柄钙皮菌Didymium iridis（Collins 1966）和多头绒泡菌（Carlile & Dee 1967）揭示二倍体原生质团可融合。当两个兼容的单倍体黏变形体混合时,产生原生质团群体,其中具有相同的遗传背景的原生质团可以发生融合,原生质团之间存在控制自我/非自我识别的不融合系统（Carlile & Gooday 1978;Collins & Betterley 1982;Schrauwen 1984）,此系统为研究某些生物学过程提供了独特的工具,例如,在细胞周期不同阶段的原生质团之间的融合导致同步有丝分裂发生（Rusch et al. 1966）;不同年龄异核体的原生质团之间的原生质融合与衰老研究（Clark & Hakim 1980;Collins & Betterley 1982;Clark & Lott 1989）;片段化的原生质团融合形成网络（Fessel et al. 2012）。
3 黏菌的生物智能研究
黏菌在营养生长阶段形成的原生质团,虽然表观形态与单核变形虫差异明显,但展现了类似变形虫的运动方式,通过扩展伪足探索行进,速度可达5cm/h（Kessler 1982）。原生质团的扇形前端可以与多个固定食物源连接,由自身组织形成交叉的管状网络系统,原生质团中的原生质通过有节奏地往复流动驱使化学信号等物质循环（Collins & Haskins 1972）。
多头绒泡菌原生质团作为模式生物也应用于生物群体智能研究中,其中的经典实验便是黏菌能够找到通过迷宫的最短路径（Nakagaki et al. 2000;Nakagaki 2001）,当黏菌原生质团覆盖网络迷宫表面,原生质团会重新分配其生物量,使其有效地定居、开发资源,通过原生质团各组织间的通讯,黏菌从多个路径中选择了连接食物并穿过迷宫的最短路径,这项开创性工作,也在后续研究取得了令人瞩目的成果,增加了迷宫问题的复杂性（Reid & Beekman 2013）。
黏菌和细胞状黏菌已被广泛用于微生物的模型系统研究,多头绒泡菌常作为运动和原生质流的研究模型,盘基网柄菌Dictyostelium discoideum则是细胞信号与发展的模式生物。黏菌原生质团提供了与网柄细胞状黏菌不同的行为策略,这些策略已经演变为利用单细胞水平的集体行为。在宏观水平上,黏菌的许多行为都与动物类似,不同层次的生物系统间具有极高的相似之处,可能反映了生物集体系统遵循了共同的设计特征（Reid & Latty 2016）。
4 黏菌的生存策略与生物地理学
黏菌子实体展现了丰富多样的形态,从具有微小有柄孢囊、孢子稀少的刺轴菌Echinostelium minutum,到大型复囊体结构、孢子极为丰富的煤绒菌Fuligo septica。研究者们通过黏菌的分布规模、子实体数量、有无柄、孢子大小、形状和纹饰特征,展示了黏菌类群内的生物学演化策略。发生于活树表面树皮栖生黏菌在生存策略上与其他类群差异显著。树皮栖生黏菌演化策略大多是形成表面积与体积比最小的原始型原生质团,在2-4d内快速形成子实体,产生单个微小的有柄孢囊,并通过易破碎的囊被释放孢子。由于活树和木质藤本树皮环境的不确定因素,树皮栖生黏菌展示了利用短暂的有利条件萌发、完成生活史的生存策略;在腐木或落叶上生长的黏菌类群遵循K选择,这些种群更适应长期潮湿且温度适宜的环境,通常在湿室培养中发生的时间也较晚（Everhart & Keller 2008）。
黏菌的物种分布通常参考其子实体阶段,而非变形鞭毛虫或原生质团的营养体阶段。一些无法发育为子实体的黏菌物种种群常常在自然环境中被忽略（Urich et al. 2008）,这些黏菌种群虽然失去了通过孢子进行长距离扩散的能力,但传播方式与土壤中变形虫群体相似,因此,某些黏菌种群的扩散范围可能比子实体记录的范围大。
在以分子标记为参考的黏菌种群跨大陆差异的黏菌生物地理学分布模式研究中,发现一些黏菌（Didymium difforme,D. squamulosum,Trichia varia）种群没有或只有微弱的地理隔离的证据（Winsett & Stephenson 2008,2011;Feng & Schnittler 2015）。但是,在全球范围内Hemitrichia serpula种群多样性研究中,某些基因型具有明显的地理局限性（Dagamac et al. 2017）,低基因流和（或）变形鞭毛虫交配型基因的突变,可能促进了区域性特有种的演化（Schnittler et al. 2017）。因此,对于评估黏菌的全球多样性,Baas-Becking模型（Finlay 2002;Finlay et al. 2004）与moderate endemicity模型（Foissner 2006;Martiny et al. 2006;Cotterill et al. 2008）哪种更符合黏菌分布模式,还有待进一步研究。
5 黏菌学的应用与挑战
黏菌学的发展从早期关注于形态结构、生命周期,扩展到生理学、生物化学和遗传学等诸多方向,甚至网络系统、信息科学等多学科交叉范围,完成了大量原创性、启发性的实验研究。此外,黏菌会产生多种具有抑菌、细胞毒性、抗氧化活性、抗肿瘤活性的代谢产物（Wang et al. 2017）,其中,从多头绒泡菌中提取的天然产物聚苹果酸（PMLA）及其纳米复合材料在抑制多种肿瘤的研究中展现了显著活性（Braud & Vert 1992;Gasslmaier et al. 2000;Lee et al. 2002;Ljubimova et al. 2008;Ding et al. 2010;Inoue et al. 2012）,是黏菌应用在人类疾病治疗的杰出案例。
黏菌分类学、系统学和生态学一直是世界黏菌的主要研究方向（李玉 2002）,随着组学研究时代的到来,借助新的技术工具、大数据等,在黏菌分类系统的划分上,将赋予更多的创新性观点和更完善的数据支持,对形态多样性与发育模式间的趋同/趋异的演化也将给出答案;另外,黏菌封闭式生命周期的不同阶段发生的开放有丝分裂（Solnica-Krezel et al. 1991）与不融合系统等诸如此类的经典现象,在新的技术下也值得进一步探索与研究。黏菌在生命科学研究中将更少地局限于自身,更多地与生态系统中的各类生物、非生物因素关联,从不同物种和细胞类型之间寻找共同的工作模式,在不同层次上理解、把握生物体系,是进一步理解生物学现象、提升研究深度的重要方向之一。
参考文献
Origin and evolution of the slime molds (Mycetozoa)
Control of cell division by very lysine rich histone (F1) phosphorylation
DOI:10.1038/247257a0 URL PMID:4361936 [本文引用: 1]
Degradation of poly (p-malic acid)-monitoring of oligomers formation by aqueous SEC and HPCE
DOI:10.1007/BF00558054 URL [本文引用: 1]
Plasmodial fusion and lethal interaction between strains in a myxomycete
DOI:10.1038/215832a0 URL PMID:6069921 [本文引用: 1]
Cell fusion in myxomycetes and fungi
In: Poste G, Nicolson Gl (eds.) Membrane fusion.
Aging of plasmodial heterokaryons in Didymium iridis
Age heterokaryon studies in Didymium iridis
DOI:10.1080/00275514.1989.12025796 URL [本文引用: 2]
Plasmodial compatibility in heterothallic and homothallic isolates of Didymium iridis
DOI:10.1080/00275514.1966.12018327 URL [本文引用: 1]
Didymium iridis in past and future research
In: Aldrich H, Daniel JW (eds.) Cell biology of Physarum and Didymium.
Genetics of somatic fusion in Physarum polycephalum: the Ppii strain
Plasmodial (somatic) fusion in a strain of Physarum polycephalum, a true slime mold, is controlled by four loci, each of which displays simple dominance. Two diploid plasmodia fuse with each other only if they are phenotypically or genotypically identical for all four fusion loci.
Conservation of protists: is it needed at all?
DOI:10.1007/s10531-007-9261-8
URL
[本文引用: 1]
Protists have scarcely been considered in traditional perspectives and strategies in environmental management and biodiversity conservation. This is a remarkable omission given that these tiny organisms are highly diverse, and have performed as key ecological players in evolutionary theatres for over a billion years of Earth history. Protists hold key roles in nearly all ecosystems, notably as participants in fluxes of energy and matter through foodwebs that centre on their predation on microbes. In spite of this, they have been largely ignored in conservation issues due to a widespread, naive belief that protists are ubiquitous and cosmopolitanously distributed. Nevertheless, recent research shows that many protists have markedly restricted distributions. These range from palaeoendemics (Gondwanan-Laurasian distribution) to local endemics. Our ignorance about the ultimate and proximate causes of such acute disparities in scale-dependent distributions of protists can be flagged as a singular reason to preserve these more cryptic participants in ecological and evolutionary dynamics. This argument is disturbing when one considers anthropogenic modifications of landscapes and the very poorly understood roles of protists in ecological processes in soils, not least in agroecolandscapes and hydrological systems. Major concerns include host specific symbiotic, symphoric and parasitic species which become extinct, unseen and largely unknown, alongside their metazoan hosts; change or loss of habitats; massive change or loss of type localities; and losses of unique genetic resources and evolutionary potential. These concerns are illustrated by examples to argue that conservation of protists should be integral to any strategy that traditionally targets vascular plants and animals. The ongoing decline in research capacity to inventory and classify protist diversity exemplifies a most acute symptom of the failures, at local, national and international levels, to support scientific responses to the biodiversity crisis. Responsible responses to these severe problems need to centre on the revival of natural history as the core discipline in biology.
Natural synchrony in a slime mold
Speciation in progress? A phylogeographic study among populations of Hemitrichia serpula (Myxomycetes)
DOI:10.1371/journal.pone.0174825
URL
PMID:28414791
[本文引用: 1]
Myxomycetes (plasmodial slime molds, Amoebozoa) are often perceived as widely distributed, confounding to the
Inhibition of brain tumor growth by intravenous poly (β-l-malic acid) nanobioconjugate with ph-dependent drug release
Cell cycle regulation of p34cdc2 kinase activity in Physarum polycephalum
Life history strategies of corticolous myxomycetes: the life cycle, fruiting bodies, plasmodial types, and taxonomic orders
Flora neotropical monograph No. 16. Myxomycetes
Sex or no sex? Independent marker genes and group I introns reveal the existence of three sexual but reproductively isolated biospecies in Trichia varia (Myxomycetes)
Physarum polycephalum percolation as a paradigm for topological phase transitions in transportation networks
DOI:10.1103/PhysRevLett.109.078103
URL
PMID:23006405
[本文引用: 1]
We study the formation of transportation networks of the true slime mold Physarum polycephalum after fragmentation by shear. Small fragments, called microplasmodia, fuse to form macroplasmodia in a percolation transition. At this topological phase transition, one single giant component forms, connecting most of the previously isolated microplasmodia. Employing the configuration model of graph theory for small link degree, we have found analytically an exact solution for the phase transition. It is generally applicable to percolation as seen, e.g., in vascular networks.
Global dispersal of free-living microbial eukaryotic species
DOI:10.1126/science.1070710
URL
PMID:12004115
[本文引用: 1]
The abundance of individuals in microbial species is so large that dispersal is rarely (if ever) restricted by geographical barriers. This
Protist diversity is different?
DOI:10.1078/1434461000160 URL PMID:15144054 [本文引用: 1]
Higher-order phylogeny of plasmodial slime molds (Myxogastria) based on elongation factor 1A and small subunit rRNA gene sequences
DOI:10.1111/jeu.2005.52.issue-3 URL [本文引用: 3]
Deep phylogeny and evolution of slime moulds (Mycetozoa)
DOI:10.1016/j.protis.2009.05.002
URL
PMID:19656720
[本文引用: 1]
Mycetozoa, characterized by spore-bearing fruiting bodies, are the most diverse Amoebozoa. They traditionally comprise three taxa: Myxogastria, Dictyostelia and Protostelia. Myxogastria and Dictyostelia typically have multispored fruiting bodies, but controversy exists whether they are related or arose independently from different unicellular ancestors. Protostelid slime moulds, with single-spored fruiting bodies, are possible evolutionary intermediates between them and typical amoebae, but have received almost no molecular study. Protostelid morphology is so varied that they might not be monophyletic. We therefore provide 38 new 18S rRNA and/or EF-1alpha gene sequences from Mycetozoa and related species, including four protostelids and the enigmatic Ceratiomyxa fruticulosa. Phylogenetic analyses support the monophyly of Dictyostelia, Myxogastria, and Ceratiomyxa (here collectively called
Biogeography and dispersal of micro-organisms: a review emphasizing protists
Synthetic substrates and inhibitors of beta-poly (l-malate)-hydrolase (polymalatase)
DOI:10.1046/j.1432-1327.2000.01573.x
URL
PMID:10931193
[本文引用: 1]
Polymalatase from Physarum polycephalum calalysed the hydrolysis of beta-poly[L-malate] and of the synthetic compounds beta-di(L-malate), beta-tetra(L-malate), beta-tetra(L-malate) beta-propylester, and L-malate beta-methylester. Cyclic beta-tri(L-malate), cyclic beta-tetra(L-malate), and D-malate beta-methylester were not cleaved, but were competitive inhibitors. The O-terminal acetate of beta-tetra(L-malate) was neither a substrate nor an inhibitor. L-Malate was liberated; the Km, Ki and Vmax values were measured. The appearance of comparable amounts of beta-tri(L-malate), and beta-di(L-malate) during the cleavage of beta-tetra(L-malate) indicated a distributive mechanism for small substrates. The accumulation of a series of oligomers, peaking with the 11-mer and 12-mer in the absence of higher intermediates, indicated that the depolymerization of beta-poly(L-malate) was processive. The results indicate that beta-poly(L-malate) is anchored at its OH-terminus by the highly specific binding of the penultimate malyl residue. The malyl moieties beyond 12 residues downstream from the OH-terminus extend into a diffuse second, electrostatic binding site. The catalytic site joins the first binding site, accounting for the cleavage of the polymer into malate residues. It is proposed that the enzyme does not dissociate from beta-poly(L-malate) during hydrolysis, when both sites are filled with the polymer. When only the first binding site is filled, the reaction partitions at each oligomer between hydrolysis and dissociation.
The Mycetozoa of North America
Calcium uptake during mitosis in the myxomycete Physarum polycephalum
DOI:10.1038/269592a0 URL PMID:917106
The nuclear replication cycle in Physarum polycephalum
In: Dove WF, Rusch HP (eds.) Growth and differentiation in Physarum polycephalum.
The Myxomycetes of Britain and Ireland. An identification Handbook
Nanobiopolymer for direct targeting and inhibition of EGFR expression in triple negative breast cancer
Myxomycetes (Mycetozoa, Schleimpilze, Pilztiere)
In: Engler HGA, Prantl KAE (eds.) Die natürlichen Pflanzenfamilien. 2nd ed. Vol. VI. W.
The Myxomycetes: introduction, basic biology, life cycles, genetics, and reproduction
In: Stephenson SL, Rojas C (eds.) Myxomycetes: biology, systematics, biogeography, and ecology.
Cell biology of Physarum and Didymium
Flora Mycologica Iberica. Vol. 2: Myxomycetes, I Ceratiomyxales, Echinosteliales, Liceales, Trichiales. Real Jardín Botánico
Water-soluble aliphatic polyesters: poly(malic acid)s
In: Doi Y, Steinbüchel A (eds.) Biopolymers: Polyesters I, Vol. 3a,
Towards a phylogenetic classification of the Myxomycetes
DOI:10.11646/phytotaxa.399.3 URL
A PSTAIRE CDK-like protein localizes in nuclei and cytoplasm of Physarum polycephalum and functions in the mitosis
DOI:10.1038/sj.cr.7290217
URL
PMID:15115619
[本文引用: 1]
CDKs play key roles in controlling cell cycle progression in all eukaryotes. In plants, multiple CDKs are present, among which the best characterized CDKs are PSTAIRE CDKs. In this study, we carried out Western blot, immunoelectron microscopy and antibody treatment with an anti-PSTAIRE monoclonal antibody to explore the subcellular localization and functions of PSTAIRE CDKs in Physarum polycephalum. The results of western blot and immunoelectron microscopy showed that in P. polycephalum, a PSTAIRE CDK-like protein was 34 kD in molecular weight and located in both nuclei and cytoplasm. In nuclei, the protein was mainly associated with chromosomes and nucleoli. The expression of the PSTAIRE CDK-like protein in both the plasmodia and nuclei showed little fluctuation through the whole cell cycle. When treated with an anti-PSTAIRE monoclonal antibody at early S phase, the cells were arrested in S phase, and the mitotic onset of P. polycephalum was blocked for about 1 h when treated at early G2 phase. Our data indicated that the PSTAIRE CDK- like protein has a direct bearing on the mitosis.
Myxomycetology: a stretch of fertile soil, a research realm of great inspiration to look forward to the prospect of world myxomycete research from the standpoint of the first, second and third international congress on the systematics and ecology of myxomycetes
Academic results in myxomycetology was presented on the basis of the First, Second and Third International Congress on the Systematics and Ecology of Myxomycetes, which were respectively held in the U.K. (in September of 1993), Spain (in April of 1996) and the U.S.A. (in June of 1999). Simultaneously discussed was the recent research development in systematics of myxomycetes, molecular biology, molecular systematology, and ecology. The trend in world myxomycete research was also predicted.
Flora fungorum sinicorum
A monograph of the Mycetozoa
2nd ed. (revised by G Lister).
A monograph of the Mycetozoa
3rd ed. (revised by G Lister).
Nanoconjugate based on polymalic acid for tumor targeting
DOI:10.1016/j.cbi.2007.01.015
URL
PMID:17376417
[本文引用: 1]
A new prototype of polymer-derived drug delivery system, the nanoconjugate Polycefin, was tested for its ability to accumulate in tumors based on enhanced permeability and retention (EPR) effect and receptor mediated endocytosis. Polycefin was synthesized for targeted delivery of Morpholino antisense oligonucleotides into certain tumors. It consists of units that are covalently conjugated with poly(beta-l-malic acid) (M(w) 50,000, M(w)/M(n) 1.3) highly purified from cultures of myxomycete Physarum polycephalum. The units are active in endosomal uptake, disruption of endosomal membranes, oligonucleotide release in the cytoplasm, and protection against enzymatic degradation in the vascular system. The polymer is biodegradable, non-immunogenic and non-toxic. Polycefin was also coupled with AlexaFluor 680 C2-maleimide dye for in vivo detection. Nude mice received subcutaneous injections of MDA-MB 468 human breast cancer cells into the left posterior mid-dorsum or intracranial injections of human glioma cell line U87MG. Polycefin at concentration of 2.5mg/kg was injected via the tail vein. In vivo fluorescence tumor imaging was performed at different time points, 0-180 min up to 24h after the drug injection. The custom-made macro-illumination imaging MISTI system was used to examine the in vivo drug accumulation in animals bearing human breast and brain tumors. In breast tumors the fluorescence signal in large blood vessels and in the tumor increased rapidly until 60 min and remained in the tumor at a level 6 times higher than in non-tumor tissue (180 min) (p<0.003). In brain tumors drug accumulated selectively in 24h without any detectable signal in non-tumor areas. The results of live imaging were corroborated histologically by fluorescence microscopic examination of various organs. In addition to tumors, only kidney and liver showed some fluorescent signal.
The systematic position of the myxomycetes
DOI:10.1080/00275514.1960.12024883 URL [本文引用: 1]
Microbial biogeography: putting microorganisms on the map
DOI:10.1038/nrmicro1341
URL
PMID:16415926
[本文引用: 1]
We review the biogeography of microorganisms in light of the biogeography of macroorganisms. A large body of research supports the idea that free-living microbial taxa exhibit biogeographic patterns. Current evidence confirms that, as proposed by the Baas-Becking hypothesis, 'the environment selects' and is, in part, responsible for spatial variation in microbial diversity. However, recent studies also dispute the idea that 'everything is everywhere'. We also consider how the processes that generate and maintain biogeographic patterns in macroorganisms could operate in the microbial world.
Maze-solving by an amoeboid organism
DOI:10.1038/35035159 URL PMID:11028990 [本文引用: 1]
Smart behavior of true slime mold in a labyrinth
DOI:10.1016/s0923-2508(01)01259-1
URL
PMID:11763236
[本文引用: 1]
Even for humans it is not easy to solve a maze. But the plasmodium of true slime mold, an amoeba-like unicellular organism, has shown an amazing ability to do so. This implies that an algorithm and a high computing capacity are included in the unicellular organism. In this report, we discuss information processing in the microorganism to focus on the issue as to whether the maze-solving behavior is akin to primitive intelligence.
A guide to temperate Myxomycetes
Die Myxomyceten Deutschlands und des angrenzenden Alpenraumes unter besonderer Berücksichtigung Österreichs. 1. Ceratiomyxales, Echinosteliales, Liceales, Trichiales
Die Myxomyceten Deutschlands und des angrenzenden Alpenraumes unter besonderer Berücksichtigung Österreichs. 2. Physarales
Die Myxomyceten Deutschlands und des angrenzenden Alpenraumes unter besonderer Berücksichtigung Österreichs. 3. Stemonitales
Les Myxomycètes
Solving the Towers of Hanoi-how an amoeboid organism effciently constructs transport networks
DOI:10.1242/jeb.081158 URL [本文引用: 1]
Collective behaviour and swarm intelligence in slime moulds
DOI:10.1093/femsre/fuw033
URL
PMID:28204482
[本文引用: 1]
The study of collective behaviour aims to understand how individual-level behaviours can lead to complex group-level patterns. Collective behaviour has primarily been studied in animal groups such as colonies of insects, flocks of birds and schools of fish. Although less studied, collective behaviour also occurs in microorganisms. Here, we argue that slime moulds are powerful model systems for solving several outstanding questions in collective behaviour. In particular, slime mould may hold the key to linking individual-level mechanisms to colony-level behaviours. Using well-established principles of collective animal behaviour as a framework, we discuss the extent to which slime mould collectives are comparable to animal groups, and we highlight some potentially fruitful areas for future research.
Sluzowce (Mycetozoa). Monografia
Some biochemical events in the life of Physarum polycephalum
In: Prescott DM, Goldstein L, McConkey E (eds). Advances in cell biology Volume 1.
Introduction
In: Dove WF, Rusch HP (eds.) Growth and differentiation in Physarum polycephalum.
Synchronization of mitosis by the fusion of the plasmodium of Physarum polycephalum
The Physarum polycephalum genome reveals extensive use of prokaryotic two-component and metazoan-type tyrosine kinase signaling
DOI:10.1093/gbe/evv237
URL
PMID:26615215
[本文引用: 1]
Physarum polycephalum is a well-studied microbial eukaryote with unique experimental attributes relative to other experimental model organisms. It has a sophisticated life cycle with several distinct stages including amoebal, flagellated, and plasmodial cells. It is unusual in switching between open and closed mitosis according to specific life-cycle stages. Here we present the analysis of the genome of this enigmatic and important model organism and compare it with closely related species. The genome is littered with simple and complex repeats and the coding regions are frequently interrupted by introns with a mean size of 100 bases. Complemented with extensive transcriptome data, we define approximately 31,000 gene loci, providing unexpected insights into early eukaryote evolution. We describe extensive use of histidine kinase-based two-component systems and tyrosine kinase signaling, the presence of bacterial and plant type photoreceptors (phytochromes, cryptochrome, and phototropin) and of plant-type pentatricopeptide repeat proteins, as well as metabolic pathways, and a cell cycle control system typically found in more complex eukaryotes. Our analysis characterizes P. polycephalum as a prototypical eukaryote with features attributed to the last common ancestor of Amorphea, that is, the Amoebozoa and Opisthokonts. Specifically, the presence of tyrosine kinases in Acanthamoeba and Physarum as representatives of two distantly related subdivisions of Amoebozoa argues against the later emergence of tyrosine kinase signaling in the opisthokont lineage and also against the acquisition by horizontal gene transfer.
Biogeographical patterns in myxomycetes
In: Stephenson SL, Rojas C (eds.) Myxomycetes: biology, systematics, biogeography, and ecology.
Cellular interaction in plasmodial slime moulds
In: Linskens HF, Heslop-Harrision J (eds.) Cellular interactions.
Eumycetozoa = Amoebozoa? SSU rDNA phylogeny of protosteloid slime molds and its significance for the amoebozoan supergroup
DOI:10.1371/journal.pone.0006754
URL
PMID:19707546
[本文引用: 2]
Amoebae that make fruiting bodies consisting of a stalk and spores and classified as closely related to the myxogastrids have classically been placed in the taxon Eumycetozoa. Traditionally, there are three groups comprising Eumycetozoa: myxogastrids, dictyostelids, and the so-called protostelids. Dictyostelids and myxogastrids both make multicellular fruiting bodies that may contain hundreds of spores. Protostelids are those amoebae that make simple fruiting bodies consisting of a stalk and one or a few spores. Protostelid-like organisms have been suggested as the progenitors of the myxogastrids and dictyostelids, and they have been used to formulate hypotheses on the evolution of fruiting within the group. Molecular phylogenies have been published for both myxogastrids and dictyostelids, but little molecular phylogenetic work has been done on the protostelids. Here we provide phylogenetic trees based on the small subunit ribosomal RNA gene (SSU) that include 21 protostelids along with publicly available sequences from a wide variety of amoebae and other eukaryotes. SSU trees recover seven well supported clades that contain protostelids but do not appear to be specifically related to one another and are often interspersed among established groups of amoebae that have never been reported to fruit. In fact, we show that at least two taxa unambiguously belong to amoebozoan lineages where fruiting has never been reported. These analyses indicate that we can reject a monophyletic Eumycetozoa, s.l. For this reason, we will hereafter refer to those slime molds with simple fruiting as protosteloid amoebae and/or protosteloid slime molds, not as protostelids. These results add to our understanding of amoebozoan biodiversity, and demonstrate that the paradigms for understanding both nonfruiting and sporulating amoebae must be integrated. Finally, we suggest strategies for future research on protosteloid amoebae and nonfruiting amoebae, and discuss the impact of this work for taxonomists and phylogenomicists.
Variable pathways for developmental changes of mitosis and cytokinesis in Physarum polycephalum
Myxomycetes of New Zealand
In: Fungi of New Zealand. Ngâ Harore o Aotearoa. Vol. 3.
Simultaneous assessment of soil microbial community structure and function through analysis of the metatranscriptome
DOI:10.1371/journal.pone.0002527
URL
PMID:18575584
[本文引用: 1]
BACKGROUND: Soil ecosystems harbor the most complex prokaryotic and eukaryotic microbial communities on Earth. Experimental approaches studying these systems usually focus on either the soil community's taxonomic structure or its functional characteristics. Many methods target DNA as marker molecule and use PCR for amplification. METHODOLOGY/PRINCIPAL FINDINGS: Here we apply an RNA-centered meta-transcriptomic approach to simultaneously obtain information on both structure and function of a soil community. Total community RNA is random reversely transcribed into cDNA without any PCR or cloning step. Direct pyrosequencing produces large numbers of cDNA rRNA-tags; these are taxonomically profiled in a binning approach using the MEGAN software and two specifically compiled rRNA reference databases containing small and large subunit rRNA sequences. The pyrosequencing also produces mRNA-tags; these provide a sequence-based transcriptome of the community. One soil dataset of 258,411 RNA-tags of approximately 98 bp length contained 193,219 rRNA-tags with valid taxonomic information, together with 21,133 mRNA-tags. Quantitative information about the relative abundance of organisms from all three domains of life and from different trophic levels was obtained in a single experiment. Less frequent taxa, such as soil Crenarchaeota, were well represented in the data set. These were identified by more than 2,000 rRNA-tags; furthermore, their activity in situ was revealed through the presence of mRNA-tags specific for enzymes involved in ammonia oxidation and CO(2) fixation. CONCLUSIONS/SIGNIFICANCE: This approach could be widely applied in microbial ecology by efficiently linking community structure and function in a single experiment while avoiding biases inherent in other methods.
Physiology and biochemistry of myxomycetes
In: Stephenson SL, Rojas C (eds.) Myxomycetes: biology, systematics, biogeography, and ecology.
Using ITS sequences to assess intraspecifc genetic relationships among geographically separated collections of the myxomycete Didymium squamulosum
Global distribution and molecular diversity of Didymium difforme
Time-lapse analysis of mitosis in vivo in macroplasmodia of Physarum polycephalum
In: Aldrich H, Daniel JW (eds.) Cell biology of Physarum and Didymium.
