Protostelids from tropical forests, woodlands and deserts in Australia

Most of what is known about the distribution of protostelids is limited to results from surveys carried out in North and Central America. To increase our knowledge about protostelid diversity and distribution we surveyed protostelids from 12 study sites in northern Queensland and the Northern Territory of Australia during May-Jun 2003. Aerial litter and ground litter samples were randomly collected along a 200 m transect at each site. Study sites ranged from tropical forests to deserts. We recovered 10 species and two apparently undescribed species from samples of aerial (dead but still attached plant parts) and ground litter. Samples from a woodland site characterized by intermediate moisture conditions had the greatest species richness, followed by samples from dry woodland, tropical forest and desert sites. When species richness for a particular microhabitat was considered, samples of aerial litter yielded more species than samples of ground litter. Percentages of samples colonized with protostelids were similar for the aerial and ground litter microhabitats within a given habitat type except for dry woodlands, in which aerial litter samples were characterized by higher numbers of species than ground litter samples. Two species (Protostelium mycophaga and Soliformovum irregularis) that in temperate North America are associated with aerial litter microhabitats also were recovered from aerial litter in dry habitats in Australia. Schizoplasmodiopsis pseudoendospora, a North American temperate ground litter species, was equally abundant in aerial litter and ground litter in Australia. This study is the first of its kind for protostelid ecology in Australia and the most extensive study of protostelids in the southern hemisphere. These data complement ongoing research on protostelid distribution from around the world.     

Protostelids and myxomycetes isolated from aquatic habitats

Protostelids and myxomycetes have been isolated from dead plant parts in many different habitats, including tropical rain forests and deserts. However underwater habitats largely have been overlooked. The purpose of this study was to determine whether protostelids do occur in aquatic habitats and to survey the myxomycetes associated with these habitats. Protostelids and myxomycetes were isolated from substrates collected from just above and just below the surface of the water. Several species of both groups were present, and their distributions above and below the water were different. It is not surprising that the trophic cells of slime molds occur in ponds because they are known to grow in films of water. However these findings are significant because this is the first study to demonstrate clearly the occurrence of protostelids in underwater environments and one of the few surveys of myxomycetes from aquatic systems.     

Ultrastructure of the Ameboid Cells of Protostelium zonatum (Mycetozoa)*

SYNOPSIS. The ameboid cells of Protostelium zonatum typically have filose pseudopodia that contain almost exclusively microfibers. Microfibers, scattered or arranged parallel in bundles, are observed in great abundance and often closely associated or directly connected with other organelles in the cytoplasm. Mitochondria typically have an expanded, undulate outer membrane and vesicular cristae containing electron-dense material which may appear denser than the mitochondrial matrix in the same section. The nucleus, as in other protostelids, contains only one centrally located nucleolus. Other organelles are essentially similar in ultrastructure to those of another nonflagellate protostelid, Protosteliopsis fimicola. Protostelium zonatum differs, however, in lacking a distinct anterior zone of hyaloplasm during migration of the ameboid cells.     

Culture and reproductive systems of 11 species of Mycetozoans

The culture and reproductive systems of 10 species (16 isolates) of myxomycetes and one species (one isolate) of protostelid were investigated. A single isolate of Ceratiomyxa fructiculosa was grown on agar and found to be nonheterothallic. This is the first report of spore-to-spore cultivation of this species and the first report of a reproductive system in the protostelids. Isolates of the myxomycetes Didymium dubium, Didymium iridis, Didymium vaccinum, Licea biforis, Perichaena vermicularis, Physarum gyrosum, Physarum pusillum (six isolates) and Semimorula liquescens all were nonheterothallic. This is the first report of culture and a reproductive system for D. vaccinum, the first report of nonheterothallism for S. liquescens and the second report of nonheterothallic isolates of D. dubium, Licea biforis, Perichaena vermicularis and P. gyrosum. The nonheterothallic isolate of D. iridis is one of many reported for this species, and the six nonheterothallic isolates of P. pusillum add to the seven nonheterothallic and two heterothallic isolates already known. In addition, five of the isolates of P. pusillum apparently represent a small form that is adapted to an ephemeral micohabitat, and the sixth is a yellow form of a species that is typically white. The Didymium ?ovoideum isolate and the two Physarum didermoides isolates have heterothallic reproductive systems. The D. ?ovoideum isolate is somewhat different from most isolates of this species in its morphology and reproductive system. It is not compatible with any of the heterothallic isolates of long-stalked Didymium, including the A0 biological species already determined for D. ovoideum; therefore, it is either a new biological species of D. ovoideum or a separate new species. The two heterothallic isolates of P. didermoides form a multiple allelic mating-type series with four alleles.     

Aquatic protostelids – a study from northeastern Germany

A survey of protostelids in ponds of northeastern Germany showed a high degree of similarity between the species assemblages from submerged aquatic and terrestrial litter. Twelve species were recovered from 115 samples. A statistical analysis of species accumulation curves indicated that 90 % of the total diversity was recovered for both aquatic and terrestrial litter. All of the more common species were observed in both aquatic and terrestrial samples. However, 24 % of all cultures from terrestrial samples were positive for protostelids, compared with only 12 % for aquatic samples. An additional 20 samples collected from the water column did not yield any protostelids. The study indicates that vegetative stages of most protostelids seem to be able to survive and probably multiply on litter submerged in fresh water, but do not live as plankton. Most probably, submerged substrata are sinks for protostelid populations.     

A habitat colonisation model for spore-dispersed organisms—Does it work with eumycetozoans?

Spore productivities and establishment probabilities of eumycetozoans were estimated and compared with quantitative data obtained from field surveys, using series of cultures of a given substrate. Spore numbers per spore case were found to increase from one to four in protostelids to up to 10⁵–10⁶ in myxomycetes, whereas average spore size decreased slightly from 14.8 μm for protostelids to 10.3 μm in myxomycetes. Spore numbers of fructifications calculated from dimensions of spores and fruit bodies were in good agreement with direct counts carried out for six species of myxomycetes. A colonisation model is presented that estimates frequencies (as a percent of successfully colonized habitat islands), which is independent of a given density of spore rain and the sexual system of the species being considered. Whereas asexual species need a minimum spore rain of ca 0.7 spores per habitat island to reach a frequency of 50 %, this figure is at least 2.4-fold higher for sexual species, depending from the incompatibility system assumed. Data from cultures indicate that the maximum potential spore rain is usually three orders of magnitude higher than the minimum figure required to create the observed frequencies. Eumycetozoans seem to follow the evolutionary trends predicted by the model. Species with sexual reproductive systems produce often more spores than asexual ones; many morphospecies have sexual and asexual strains; and back-conversion from sexual to asexual reproduction occurs occasionally.     

“Candidatus Midichloriaceae” fam. nov. (Rickettsiales), an Ecologically Widespread Clade of Intracellular Alphaproteobacteria

“Candidatus Midichloria mitochondrii” is an intramitochondrial bacterium of the order Rickettsiales associated with the sheep tick Ixodes ricinus. Bacteria phylogenetically related to “Ca. Midichloria mitochondrii” (midichloria and like organisms [MALOs]) have been shown to be associated with a wide range of hosts, from amoebae to a variety of animals, including humans. Despite numerous studies focused on specific members of the MALO group, no comprehensive phylogenetic and statistical analyses have so far been performed on the group as a whole. Here, we present a multidisciplinary investigation based on 16S rRNA gene sequences using both phylogenetic and statistical methods, thereby analyzing MALOs in the overall framework of the Rickettsiales. This study revealed that (i) MALOs form a monophyletic group; (ii) the MALO group is structured into distinct subgroups, verifying current genera as significant evolutionary units and identifying several subclades that could represent novel genera; (iii) the MALO group ranks at the level of described Rickettsiales families, leading to the proposal of the novel family “Candidatus Midichloriaceae.” In addition, based on the phylogenetic trees generated, we present an evolutionary scenario to interpret the distribution and life history transitions of these microorganisms associated with highly divergent eukaryotic hosts: we suggest that aquatic/environmental protista have acted as evolutionary reservoirs for members of this novel family, from which one or more lineages with the capacity of infecting metazoa have evolved.     

Species-specific cell mobility of bacteria-feeding myxamoebae in plasmodial slime molds

On decaying wood or litter in forests, plasmodial slime molds (myxomycetes) represent a large fraction of eukaryotic protists that feed on bacteria. In his seminal book Experimental Physiology of Plants (1865), Julius Sachs referred to the multinucleate plasmodium of myxomycetes, which were considered at that time as primitive plants (or fungi). Today it is well established that myxomycetes are members of the Amoebozoa (Protista). In this study we compare the mobility of myxamoebae of 3 European species, Lycogala epidendrum (order Liceales), Tubulifera arachnoidea, and Trichia decipiens (order Trichiales). Using agar plates, on which 3 separate bacterial species were cultivated as prey organisms (Methylobacterium mesophilicum, Escherichia coli, Agrobacterium tumefaciens), we document large differences in cell motility between the myxomycetes investigated. In addition, we show that the 3 species of myxamoebae can be distinguished based on their average cell size. These data shed light on the mode of co-occurrence via differential substrate utilization in these members of the Amoebozoa.     

Myxomycete diversity and distribution from the fossil record to the present

The myxomycetes (plasmodial slime molds or myxogastrids) are a group of eukaryotic microorganisms usually present and sometimes abundant in terrestrial ecosystems. Evidence from molecular studies suggests that the myxomycetes have a significant evolutionary history. However, due to the fragile nature of the fruiting body, fossil records of the group are exceedingly rare. Although most myxomycetes are thought to have very large distributional ranges and many species appear to be cosmopolitan or nearly so, results from recent studies have provided evidence that spatial distribution patterns of these organisms can be successfully related to (1) differences in climate and/or vegetation on a global scale and (2) the ecological differences that exist for particular habitats on a local scale. A detailed examination of the global distribution of four examples (Barbeyella minutissima, Ceratiomyxa morchella, Leocarpus fragilis and Protophysarum phloiogenum) demonstrates that these species have recognizable distribution patterns in spite of the theoretical ability of their spores to bridge continents. Special Issue: Protist diversity and geographic distribution. Guest editor: W. Foissner.     

Eumycetozoa?=?Amoebozoa?: SSUrDNA Phylogeny of Protosteloid Slime Molds and Its Significance for the Amoebozoan Supergroup

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.     

Sporocarp Ulrastructure and Development in the Protostelid Cavostelium apophysatum1

Ultrastructural observations on the sporocarp of the protostelid Cavostelium apophysatum are presented, including information about the mechanism of sporocarp development. The onset of sporogenesis is marked by cessation of trophic activity and the secretion of a protective sheath. The protoplast gradually molds itself into two distinct zones approximating the shape of the final sporocarp–a hyaloplasmic pre-stalk zone and a globose incipient spore zone. The protoplast in the stalk zone deposits a fibrillar and amorphous stalk acropetally as the stalk protoplast moves into the incipient spore region. The last portion of the stalk to be deposited is the apophysis, a hollow cup-like structure at the stalk apex. Spore wall deposition begins as the stalk nears completion. The wall consists of a single electron-dense layer ornamented with hollow cones and solid projections. The mechanism of sporocarp development in C. apophysatum is compared to the developmental patterns of the protostelids Planoprotostelium aurantium and Schizoplasmodiopsis amoeboidea.     

黏菌分类学史研究

黏菌是菌物中一个特殊和有趣的类群。为了准确而深刻地认识黏菌的内涵、多样性和系统发育关系等分类学问题,本文从黏菌命名起点开始循览黏菌分类学的发展历程,结合黏菌分类学的最新研究进展,考证了黏菌纲Myxomycetes内涵的变化和分类系统的演变及黏菌分类学研究的重要事件,并论述了中国黏菌分类学研究史,从而系统阐述了国内外黏菌分类学研究历史的沿革和演化。     

辽宁省黏菌初步研究

为掌握辽宁省的黏菌资源,在位于辽宁省宽甸县的白石砬子国家自然保护区和桓仁县的老秃顶子国家级自然保护区进行了黏菌标本的采集,并根据形态特征进行了鉴定;复核了吉林农业大学菌物研究所标本馆保存的辽宁省产的黏菌标本,明确了辽宁省已知黏菌5目8科24属90种,其中有5个属为辽宁省新记录属,有34个种为辽宁省新记录种.     

小兴安岭两种林地的黏菌物种多样性

黏菌广泛分布于森林生态系统中, 并在生态系统的物质循环过程中发挥重要的功能。为了探讨黏菌在小兴安岭森林中的物种多样性及其分布, 本文对该地区的汤旺河兴安石林森林公园和胜山国家级自然保护区系统开展黏菌多样性调查研究。在2个地区共采集黏菌标本248份, 基于形态学特征共鉴定出4目8科17属44种黏菌, 其中Craterium dictyosporum、垂头绒泡菌(Physarum album)和Reticularia splendens var. jurana等10个种为黑龙江省首次报道。多样性分析结果显示, 汤旺河兴安石林森林公园针阔混交林的黏菌物种多样性(36种)高于胜山国家级自然保护区红松(Pinus koraiensis)林内的黏菌物种多样性(25种), 其中两地间共有的黏菌有17种, 黏菌物种组成的相似性(C_S)为55.7%。绿绒泡菌(Physarum viride)是针阔混交林内的优势种, 蛇形半网菌(Hemitrichia serpula)是红松林内的优势种。研究结果表明植被类型对黏菌的物种组成和多样性有着重要的影响。     

鼎湖山自然保护区黏菌的物种组成和多样性

为了揭示鼎湖山自然保护区黏菌的物种组成及物种多样性在不同生境的异同,该研究选择6个不同海拔高度的样地,从中收集地面基物和树皮基物进行湿室培养,通过物种鉴定和发生数量统计分析物种的组成和多样性。结果表明:共计获得6目8科18属49种黏菌,其中绒泡菌目(Physarales)最多(17种),其次为团毛菌目15种、发网菌目(Stemonitales)11种、无丝菌目(Lieeales)4种、鹅绒菌目(Ceratiomyxales)和刺轴菌目(Eehinosteliales)分别各1种。主要优势种为灰团网菌(Arcyria cinerea)(RA=27.03%)和垫形双皮菌(Diderma effusum)(RA=21.14%)。随着海拔的升高,黏菌物种多样性逐渐降低,Shannon-Wiener多样性指数最低值出现在海拔300 m处,为1.66±0.12;而其优势集中性指数最高,为0.25±0.05。两个样地的海拔高度相距越大,共有的物种数越少相似性指数越低。雨季共获得黏菌33种,旱季共获得黏菌40种,共有种为22种,相似性系数为60.27%,旱季基物上发生的黏菌Shannon-Wiener多样性指数显著高于雨季。地面基物上的黏菌物种数为39种,高于树皮基物的26种,且两者的Shannon-Wiener多样性指数具有显著性差异,表明黏菌对地面基物的偏好性大于树皮基物。     

甘肃省祁连山国家级自然保护区的黏菌物种多样性

黏菌是森林生态系统中不可或缺的生物资源, 在生态系统中发挥重要的作用。为了探讨黏菌在西北地区森林中的物种多样性及影响物种组成和多样性的因素, 本文对甘肃省祁连山国家级自然保护区进行为期2年的多点调查采样, 获得黏菌标本826份, 经形态学鉴定属于4目5科22属71种, 其中甘肃省新记录种30种。发现鹅绒菌(Ceratiomyxa fruticulosa)等9个物种是祁连山保护区广泛分布的物种, 针叶林中的黏菌总物种数(58种)和特有物种数(38种)均高于阔叶林(33种; 13种), 海拔高度对黏菌多样性无明显影响。主成分分析结果表明, 腐木型基质上的黏菌物种多样性最丰富, 木本基物与草本基物上的黏菌物种组成具有明显差异。研究结果表明, 甘肃省祁连山自然保护区的山地森林带的植被类型与基物类型是影响黏菌物种组成和多样性的重要因素。     

湖北省兴山县黏菌的物种组成与生态特征

湖北省宜昌市兴山县地处北亚热带,位于秦巴山区向江汉平原的东延区域,属"三峡库区",气候湿润,植被主要为常绿阔叶与落叶阔叶混交林,适宜黏菌生长.为全面掌握该县黏菌的物种资源组成,从而加强对"三峡库区"生物多样性的认识,在2016年10月至2018年8月,于不同季节在该县进行了10次黏菌多样性调查和标本采集,同时收集基物进...     

Phylogeny of the scathophagidae (Diptera, calyptratae) based on mitochondrial DNA sequences

The family Scathophagidae constitutes, together with members of the families Muscidae, Fannidae, and Anthomyiidae, the Muscoidea superfamily. The species Scathophaga stercoraria has been used extensively to investigate questions in animal ecology and evolution, particularly as a model system for studies of sperm competition and life history evolution. However, no phylogenetic studies have ever been performed on the Scathophagidae and the relationships within this family remain unclear. This study represents a molecular approach aimed at uncovering the phylogenetic relationships among 61 species representing 22 genera of Scathophagidae. A fragment of the terminal region of the mitochondrial gene COI (subunit I of the cytochrome oxidase gene) was sequenced in scathophagid species covering a wide geographic area, as well as a diverse spectrum of ecological habitats. Several clades grouping different genera and species have been identified, but the resolution power of the COI was insufficient to establish the exact relationships between these clades. The molecular data confirm the existence of a group consisting of the genera Delina, Chylizosoma, and Americina, which could represent the subfamily Delinae. Concerning the controversial position of the genus Phrosia, our data clearly suggest that it should be removed from the Delinae and placed within the genus Cordilura. Monophyly of most genera was confirmed, except for the genus Scathophaga, which should be divided into several different taxa.     

长春地区黏菌区系特征

为调查长春地区黏菌资源的物种多样性,便于掌握长春地区黏菌资源情况,对长春地区的黏菌进行了为期3年的系统调查,共采集到标本2,000余份,通过形态特征鉴定为5目7科23属59种。团毛菌科、绒泡菌科和发网菌科为优势科,共计49种,占长春地区黏菌总种数的83.1%,科的数目占总科数的42.8%。团网菌属、半网菌属、团毛菌属、绒泡菌属和发网菌属为优势属,共计34种,占总种数的57.6%。从种的组成上可以划分为世界广布种（67.8%）,北温带分布种（10.17%）,东亚-北美洲间断分布种（5.08%）,温带-亚热带