簇生岐柄菌的超微形态学研究

为揭示网柄细胞状黏菌的超微结构特征,对簇生岐柄菌Cavenderia fasciculata生活史过程中的孢子、黏变形体和柄细胞3种类型的细胞超微结构进行系统观察,并与目前仅知的3种网柄细胞状黏菌的超微结构进行比较。结果表明：簇生岐柄菌C. fasciculata的孢子、黏变形体和柄细胞内均有线粒体结构,随着细胞分化,线粒体内部结构逐渐破坏,并被自噬泡吞噬;孢子表面具有线状纹饰。     

河南省网柄细胞状黏菌的研究

从在河南省采集的75份基物中共分离得到14株网柄细胞状黏菌,其中网柄菌属Dictyostelium的圆头网柄菌D.sphaerocephalum、棒形网柄菌D.clavatum和紫网柄菌D.purpureum和轮柄菌属Polysphondylium的亮白轮柄菌P.candidum、紫轮柄菌P.violaceum和纤细轮柄菌P.tenuissium,均为河南省新记录种。文中对该6种网柄菌进行了形态学描述,并附有生长发育部分阶段形态和显微照片。     

网柄细胞状黏菌的化学成分及药理作用研究进展

文中综述了从网柄细胞状黏菌中分离得到的DIF-1及其衍生物、氯代苯并呋喃、三联苯化合物等芳香族化合物,脂肪酸和磷酸化合物、酶以及糖类等,并介绍了各成分的药理或生理作用等。表明网柄细胞状黏菌可以成为某些活性成分及药物的新来源。     

基于脂肪酸生物标记的网柄细胞状黏菌分类学研究初探

本文测定和分析6种网柄细胞状黏菌的脂肪酸组分,进行以其作为网柄细胞状黏菌分类特征的探讨。结果表明,脂肪酸组分可将6种网柄菌有效区分,且与形态分类结果较为一致,因此建议将脂肪酸生物标记作为网柄菌分类的依据之一。     

网柄细胞状黏菌纯化培养基的改进

网柄细胞状黏菌传统的分离培养是在添加细菌的培养基上进行的。选取了9种网柄细胞状黏菌作为研究对象,在不饲喂任何细菌的条件下于3种培养基上进行培养,通过对生长状态的比较,发现燕麦片琼脂培养基对于纯化网柄细胞状黏菌具有较好的效果。     

网柄细胞状黏菌生态学的研究进展

网柄细胞状黏菌(简称网柄菌)是黏菌的第二大类群,对其生态特征的研究有助于深入了解这类生物适宜的生存条件和人类活动的影响。本文回顾了1869年至今的网柄菌生态学研究历史,从地理因素、植被因素、生物因素三个角度,探讨了影响网柄菌物种丰度和多度的生态因素,从而为土壤及凋落物中黏菌的物种多样性保护提供参考。     

硬基网柄菌Dictyostelium firmibasis生活史的研究

本文研究了网柄细胞状黏菌中国新记录种硬基网柄菌Dictyostelium firmibasis从孢子-黏变形体-细胞集群-假原质团-成熟孢堆果的无性生活循环过程。结果表明：该种细胞状黏菌孢子萌发至少需要8h,孢子萌发释放出具有不规则形状的黏变形体,黏变形体无色并进行不规则的高速运动;黏变形体细胞集群为典型的辐射状;孢堆果对光极为敏感,在成熟发育期微弱的光刺激便会导致子实体生长畸形或停止生长并死亡;从集群开始形成到孢堆果成熟持续约12-14h,完成一个完整的生活史循环约需36-38h。     

网柄细胞状黏菌生物学特性及其应用研究进展

网柄细胞状黏菌是一类介于植物和动物之间的原生生物。尽管形态微小,但因为同时具有动物细胞和植物细胞的特点,且生命周期短暂易重复,故而对其进行生物学特性及应用的研究具有重要价值。本文从网柄细胞状黏菌的生活史循环、生物学特性、生态多样性、在医学和药物领域的探索及其与其他微生物关系等5个方面探讨网柄细胞状黏菌的生物学特性及应用的研究进展及意义,展望网柄细胞状黏菌未来在医学和生态等方面的研究前景及其潜在的应用价值,旨在为我国网柄细胞状黏菌同其他领域的交叉研究相结合提供视野,探索其在促进人类的科学进步、改善生活环境及攻克疾病方面的作用及意义。     

黏菌的近亲远邻

正人们经常提到的"黏菌"一词,实际上为广义的黏菌,包括网黏菌、内寄生黏菌根肿菌、网柄细胞状黏菌、集胞细胞状黏菌及真黏菌等五大类,除网黏菌被归为茸鞭生物界外,其余均属于原生生物界。这里所谓的真黏菌就是我们所要讲述的黏菌,而其余四种黏菌则是真黏菌的"近亲"了,因它们的形态或多或少有相似之处,故在最初的分类系统中,将它们称为"兄弟姐妹"。     

集胞菌的初步研究

本文报告了网柄菌属(Dictyostelium)的4个种:毛霉状网柄菌(D.mucoroides Brefeld)、小网柄菌(D.minutum Raper)、紫网柄菌(D.purpureum Olive)和盘基网柄菌(D.discoideumRaper)。轮柄菌属(Polysphondylium)的1个种,即紫轮柄菌(P.violaceum Brefeld)。共5个种,以上均为我国新记录。此外,又增补了一些分离培养的方法,对每个种的生活史进行了观察,并提出了小囊胞应纳入生活史中。     

Occurrence and distribution of dictyostelid cellular slime molds in Norway

The distribution of eleven dictyostelid cellular slime molds found in Norway was studied. They were divided into four groups according to their dominance. In decreasing order the groups were: (1) two varieties of Dictyostelium mucoroides , (2) D. aureostipes and Polysphondylium violaceum , (3) D. fasciculatum, D. minutum, P. pallidum and Dictyostelium sp. 1, and (4) Dictyostelium sp. 2 and 3 and Acytostelium lep–tosomum. Differences in distribution related to altitudes and latitudes, climates and dominant tree species were observed for some species.     

Ground-feeding migratory songbirds as cellular slime mold distribution vectors

Cosmopolitan species of cellular slime molds occur continents apart in both tropical and temperate zones of the world though the spore masses are too heavy to be wind borne, and water dispersal is limited to the watercourses. A highly mobile distribution vector was found in ground-feeding migratory song birds. Nine ubiquitous species and 2 ecologicially distinct species of dictyostelid cellular slime molds were isolated from the feces of ground-feeding eastern North American migratory thrushes, finches, sparrows and warblers, both on breeding and winter grounds. Three propagules of slime molds, amoebae, spores and macrocysts survive passage through the avian digesive tract and remain in the gut long enough to be transported by major bird migrations. Habitats with the greates species diversity of both cellular slime molds and ground-feeding passerines concur in both eastern North America and Central America. Birds actively seek their prefered habitats; the cellular slime molds have arrived at these habitats as passengers. Rare slime molds can serve as a marker to the habitats that migratory birds have visited, or birds with known habitats can provide clues as to the distribution of rare species of cellular slime molds.     

Description of dictyostelid cellular slime mold species in Norway

Ten different species of dictyostelid cellular slime molds were found in Norway, namely Dictyostelium mucoroides Brefeld, D. sp. 1, D. sp. 2, D. aureo–stipes Cavender, Raper & Quinlan, D. fasckulatum Traub, Hohl & Cavender, D. sp. 3, D. minutum Raper, Polysphondylium violaceum Brefeld, P. pallidum Olive and Acylo–stelium leptosomum Raper & Quinlan. D. mucoroides included two varieties, D. sp. 1 and D. sp. 2 are probably related to D. septentrionalis Cavender and D. sphaerocephalum (Oud.) Sacc. & March respectively and D. sp. 3 is probably a new species.
Two different spore types, characterized by the presence or absence of ribosomes on the outer mitochondrial membranes, were revealed by transmission electron microscopic studies. This property was related to other properties such as the presence or absence of polar spore granules (PG) and the aggregative responses of the amoebae towards cAMP.     

Distribution and ecology of dictyostelids in China

Dictyostelid cellular slime molds are a ubiquitous component of most soils, where they feed upon bacteria and other microbes and thus play an essential role in the soil ecosystem. Herein we review the available literature on dictyostelid cellular slime molds in China, especially their diversity and ecology. The patterns of distribution for these organisms in relation to the different habitats with which they are associated are analyzed and discussed. In addition, the assemblages of dictyostelids reported from China and the United States were compared. The CC value obtained (0.48) indicates that China and the United States are perhaps less similar than might be expected. Our data point out the need for further studies to characterize more completely the assemblages of dictyostelids associated with particular vegetation types or particular regions throughout the world.     

Taxonomy, slime molds, and the questions we ask

Taxonomic treatments often influence the way we both ask and attempt to answer certain biological questions. The classical taxonomy of the dictyostelid cellular slime molds (Dictyosteliales) involves a convenient set of categories that were developed independent of phylogeny. In order to test whether the characters supporting the classical taxonomy hold any phylogenetic signal, we subjected 19 described taxa belonging to two families (Acytosteliaceae and Dictyosteliaceae) and three genera (Acytostelium, Dictyostelium, and Polysphondylium) to rooted cladistic analyses using PAUP* v 4.0b4a. Neither family nor any of the three genera were found to represent monophyletic groups. These results confirm that the classical taxonomy used to delineate families and genera within these slime molds carries very little phylogenetic signal. Taxonomic character sets should be scrutinized phylogenetically in order to determine what information they provide about the relatedness of taxa within a group. Because taxonomy often drives the nature of biological inquiry, caution should be exercised when drawing conclusions regarding the evolution of developmental systems in Dictyostelium.     

Intracellular cyclic GMP-binding proteins in cellular slime molds.

The complexity of cyclic GMP-binding activity in the 48,000 X g supernatant of three species of the cellular slime molds (Dictyostelium discoideum, Dictyostelium rosarium, and Polysphondylium violaceum) was studied by gel filtration chromatography on AcA 34 Ultrogel. All these species have in common a cyclic GMP-binding protein of molecular weight of about 2.5 X 10(5) which specifically binds this nucleotide. In addition, Scatchard plots of assays carried out with the 48,000 X g supernatant of these species exhibit cyclic GMP-binding activity with an apparent dissociation constant of about 1 nM. None of the cyclic GMP-binding proteins separated by chromatography on AcA 34 Ultrogel was associated to protein kinase activity stimulation. In view of the cyclic GMP function during chemotactic transduction in the cellular slime molds, the possible molecular function for this 2.5 X 10(5)-dalton cyclic GMP-binding protein is discussed.