Atradidymella muscivora gen. et sp. nov. (Pleosporales) and its anamorph Phoma muscivora sp. nov.: A new pleomorphic pathogen of boreal bryophytes

During a survey of bryophilous fungi from boreal and montane habitats, 12 isolates of a hitherto unknown plant pathogenic member of the Pleosporales were recovered from Aulacomnium palustre, Hylocomium splendens, and Polytrichum juniperinum, and described as Atradidymella muscivora gen. et sp. nov. Atradidymella is characterized by minute, unilocular, setose pseudothecia having 2-3 wall layers; brown, fusiform, 1-septate ascospores; and a Phoma anamorph. The genus is distinguished from all other pleosporalean genera with brown, fusiform ascospores on the basis of ascospore and pseudothecium morphology and a highly reduced stroma that is localized within a single host cell. Atradidymella muscivora is distinguished by its minute pseudothecia (<115 μm) and ascospores that are slightly allantoid and constricted at the septum with the upper cell often wider than the lower. Its anamorph, Phoma muscivora sp. nov., is morphologically distinguishable from P. herbarum in having smaller conidia. Parsimony analysis of the ITS rDNA region indicates A. muscivora has affinities to the Phoma-Ascochyta-Didymella clade that is sister to the Phaeosphaeriaceae within the Pleosporales.     

RELATION OF DWARFMISTLETOE (ARCEUTHOBIUM) TO THE XYLEM TISSUE OF CONIFERS. II. EFFECT OF THE PARASITE ON THE XYLEM ANATOMY OF THE HOST12

Srivastava , L. M., and K. Esau , (U. California, Davis.) Relation of dwarfmistletoe (Arceuthobium) to the xylem tissue of conifers. II. Effect of the parasite on the xylem anatomy of the host. Amer. Jour. Bot. (48(3): 209–215. Illus. 1961.—The changes in the xylem anatomy induced by dwarfmistletoe infection were studied in 7 coniferous species. The most pronounced abnormalities are observed in the shape and size of the infected rays. Because of the presence of parasite tissue, the rays assume a hypertrophied appearance; moreover, they fuse to form large composite rays. The union of rays involves intrusive growth of ray cells and displacement of fusiform initials. Some division of fusiform initials also occurs. Rays may increase in number and they may contain more host cells than normal rays. Axial tracheids in infected host woods differ more or less strongly from those of noninfected woods. They may be shorter, wider, and more irregular in shape than the axial tracheids in healthy wood. The samples of xylem from infected pines had a larger number of resin canals than those from healthy trees. Resin canals were also found in infected Tsuga, which normally lacks these structures.     

Pauciconfibula patagonensis sp. nov. (Monogenea: Microcotylidae) parasitizing the horsefish, Congiopodus peruvianus (Pisces: Congiopodidae), from the Patagonian Shelf, Argentina

Pauciconfibula patagonensis sp. nov. (Monogenea: Microcotylidae), parasite of gill filaments of the horsefish, Congiopodus peruvianus (Congiopodidae) collected in the Patagonian Shelf, Argentina, is described and illustrated. The new species is characterized by having intestinal caeca not confluent and entering into the haptor, vitelline follicles extending from the genital pore to near the posterior portion of haptor, two parallel rows each comprised of 16-20 microcotylid clamps in the haptor, 25-43 testes and a fusiform egg with one very long tangled polar filament. P. patagonensis is the only member of the genus known to parasitize a scorpaeniform host and represents the first record of a representative of this genus in the southern Atlantic Ocean.     

云南油杉枝锈病一新病原——油杉被孢锈(新种)

本义报道了在云南油杉(Keteleeria evelyniana Mast.)上引起枝干锈病的被孢锈属一新种——油杉被孢锈Peridermium keteleeriae-evelynianae Zhou et Chen,并从所致病害症状、锈子器和锈孢子的形态特点、锈孢子表面纹饰的扫描电镜观察等方面,讨论了新种与另一种云南油杉枝干锈病病原——昆明被孢锈(Peridermium kunmingense Jen)的主要区别。     

云南油杉枝锈病一新病原———油杉被孢锈(新种)

本义报道了在云南油杉(Keteleeria evelyniana Mast.)上引起枝干锈病的被孢锈属一新种——油杉被孢锈Peridermium keteleeriae-evelynianae Zhou et Chen,并从所致病害症状、锈子器和锈孢子的形态特点、锈孢子表面纹饰的扫描电镜观察等方面,讨论了新种与另一种云南油杉枝干锈病病原——昆明被孢锈(Peridermium kunmingense Jen)的主要区别。     

Prosthecobacter fusiformis nov. gen. et sp., the fusiform caulobacter

Four strains of heterotrophic, fusiform caulobacters have been isolated from freshwater sources. A single prostheca extends from one pole of mature cells, and cells attach to various substrata by means of a holdfast located at the distal tip of the appendage. Thus, superficially these bacteria bear a strong resemblance to bacteria in the genus Caulobacter. However, unlike Caulobacter these bacteria do not exhibit a dimorphic life cycle of motile, non-stalked daughter cells and immotile, stalked mother cells. Instead both mother and daughter cells are immotile, and at the time of cell separation the daughter cells are essentially identical mirror-image replicas of the mother cell. In addition, the prosthecae of these fusiform caulobacters do not have crossbands, they are somewhat wider than the stalks of Caulobacter and the pseudostalks of Asticcacaulis, and they terminate in a bulbous tip. The deoxyribonucleic acid (DNA) base composition ranges from 54.6–60.1, well below the 62–67 range for the genus Caulobacter. Based upon these and other differences, a new genus and species, Prosthecobacter fusiformis, is proposed for the fusiform caulobacters.     

Phialomyces fusiformis sp. nov. from soil in Singapore is identified and described

Phialomyces fusiformis sp. nov., isolated from soil in Singapore, is described and illustrated. The species is similar to P. macrosporus-type species of the genus but differs in that it has longer, more ellipsoid-limoniform, fusiform and more coarsely ornamented conidia.     

Regulation of cellular morphology by the Rous sarcoma virus src gene: analysis of fusiform mutants.

We have been interested in how Rous sarcoma virus (RSV) influences transformed cell morphology and compared the molecular properties of chicken embryo cells (CEC) infected with mutants of RSV that induce the fusiform transformed cell morphology with those of CEC infected by wild-type RSV, which induces the more normal round transformed cell morphology. We looked for properties shared by all fusiform mutant-infected cells, because these may be responsible for maintaining the fusiform morphology. Five different fusiform mutants, two wild-type RSVs, and one wild-type back revertant of a fusiform mutant were studied. In the fusiform mutant-infected cells, the localization and myristylation of pp60src were determined and the extent of expression of the extracellular matrix protein fibronectin was examined at both the mRNA and protein levels. The phosphorylation of vinculin on tyrosine also was examined in the same CEC. Within all fusiform mutant-transformed CEC, pp60src was dramatically absent from the adhesion plaque sites normally seen in cells transformed with wild-type RSV, and these transformed CEC all expressed more fibronectin mRNA and protein in the extracellular matrix than did the wild-type RSV-transformed CEC. The absence of pp60src from the adhesion plaques was not due to lack of myristylation of the src protein, and tyrosine phosphorylation of vinculin was not related to fibronectin expression. These results suggest that the inverse relationship between pp60src in the adhesion plaques and fibronectin expression in the extracellular matrix may be interconnected phenomena and could be related to the maintenance of the fusiform transformed morphology.     

Conlarium duplumascospora gen. et. sp. nov. and Jobellisia guangdongensis sp. nov. from freshwater habitats in China

Conlarium duplumascospora gen. et. sp. nov. and Jobellisia guangdongensis sp. nov. are described and illustrated from submerged wood collected from Guangdong Province, China. Conlarium duplumascospora is characterized by gregarious, coriaceous and beaked ascomata; cylindrical, unitunicate asci with a bipartite apical ring; biseriate, fusiform, hyaline, 0-5-septate ascospores with or without appendages; and anamorph with muriform conidia. Jobellisia guangdongensis is characterized by globose to subglobose, gregarious and papillate ascomata; three-layered peridium; cylindrical, unitunicate asci with a refractive apical ring; and one-septate, fusiform, greenish brown ascospores. Sequence analyses of partial nuclear large subunit ribosomal DNA (LSU rDNA) were performed to infer the phylogenetic affinities of these new taxa. A key to species of Jobellisia is provided.     

Linker insertion-deletion mutagenesis of the v-src gene: isolation of host- and temperature-dependent mutants.

The host cell regulators and substrates of the Rous sarcoma virus transforming protein pp60v-src remain largely unknown. Viral mutants which induce a host-dependent phenotype may result from mutations which affect the interaction of pp60v-src with host cell components. To isolate such mutants and to examine the role of different regions of src in regulating pp60v-src function, we generated 46 linker insertion and 5 deletion mutations within src. The mutant src genes were expressed in chicken embryo fibroblasts and in rat-2 cells by using retrovirus expression vectors. Most linker insertions within the kinase domain (residues 260 to 512) inactivated kinase activity and transforming capacity, while most insertions in the N-terminal domain and at the extreme C terminus were tolerated. A number of mutations generated a host-dependent phenotype. Insertions after residues 225 and 227, within the N-terminal regulatory domain (SH2), produced a fusiform transformation in chicken embryo fibroblasts and abolished transformation in rat-2 cells; a similar phenotype also resulted from two deletions affecting SH2 (residues 149 to 174 and residues 77 to 225). Insertions immediately C terminal to Lys-295, which is involved in ATP binding, also produced a conditional phenotype. Insertions after residues 299 and 300 produced a temperature-sensitive phenotype, while insertions after residues 304 and 306 produced a host cell-dependent phenotype. An insertion which removed the major tyrosine autophosphorylation site (Tyr-416) greatly reduced transformation of rat-2 cells, a property not previously observed with other mutations at this site. We conclude that mutations at certain sites within src result in conditional phenotypes. These sites may represent regions important in interactions with host cell components.     

A novel single-tailed fusiform Sulfolobus virus STSV2 infecting model Sulfolobus species

A newly isolated single-tailed fusiform virus, Sulfolobus tengchongensis spindle-shaped virus STSV2, from Hamazui, China, is characterised. It contains a double-stranded modified DNA genome of 76,107 bp and is enveloped by a lipid membrane structure. Virions exhibit a single coat protein that forms oligomers when isolated. STSV2 is related to the single-tailed fusiform virus STSV1 and, more distantly, to the two-tailed bicaudavirus ATV. The virus can be stably cultured over long periods in laboratory strains of Sulfolobus and no evidence was found for cell lysis under different stress conditions. Therefore, it constitutes an excellent model virus for archaeal virus–host studies.     

The identification of myogenic cells in regenerating skeletal muscle. I. Early anuran regenerates.

Muscle regeneration is usually considered to involve two easily recognizable mononuclear cell populations: (a) irregularly shaped phagocytic macrophages; and (b) fusiform myogenic cells which reside beneath the basal lamina of the injured myofibers. The present study finds that anuran macrophages can mimic early myogenic cells by adopting a fusiform shape and a sublaminar position during the initial stages of phagocytic infiltration. Implants of minced gastrocnemius muscle from adult Rana pipiens and R. clamitans were used. Macrophage cytology was examined in normally regenerating implants and implants mixed with carbon tracer particles. Implants of nonliving muscle, lyophilized or frozen repeatedly prior to implantation, were also prepared to study the process of macrophage invasion free from contamination by any endogenous myogenic cells. Ultrastructural examination of normal implants finds no clear morphological boundaries by which early myogenic cells and macrophages can reliably be separated. Studies of carbon-marked implants demonstrate the occurrence of numerous, carbon-labeled fusiform sublaminar macrophages. Fusiform macrophages are also found in the myofibers of the implanted muscle tissues killed by previous freezing or lyophilization. These observations indicate that the criteria of cell shape and location traditionally used for myogenic cell identification are of doubtful validity and must be reevaluated.     

The motility symbiont of the termite gut flagellate Caduceia versatilis is a member of the "Synergistes" group

The flagellate Caduceia versatilis in the gut of the termite Cryptotermes cavifrons reportedly propels itself not by its own flagella but solely by the flagella of ectosymbiotic bacteria. Previous microscopic observations have revealed that the motility symbionts are flagellated rods partially embedded in the host cell surface and that, together with a fusiform type of ectosymbiotic bacteria without flagella, they cover almost the entire surface. To identify these ectosymbionts, we conducted 16S rRNA clone analyses of bacteria physically associated with the Caduceia cells. Two phylotypes were found to predominate in the clone library and were phylogenetically affiliated with the "Synergistes" phylum and the order Bacteroidales in the Bacteroidetes phylum. Probes specifically targeting 16S rRNAs of the respective phylotypes were designed, and fluorescence in situ hybridization (FISH) was performed. As a result, the "Synergistes" phylotype was identified as the motility symbiont; the Bacteroidales phylotype was the fusiform ectobiont. The "Synergistes" phylotype was a member of a cluster comprising exclusively uncultured clones from the guts of various termite species. Interestingly, four other phylotypes in this cluster, including the one sharing 95% sequence identity with the motility symbiont, were identified as nonectosymbiotic, or free-living, gut bacteria by FISH. We thus suggest that the motility ectosymbiont has evolved from a free-living gut bacterium within this termite-specific cluster. Based on these molecular and previous morphological data, we here propose a novel genus and species, "Candidatus Tammella caduceiae," for this unique motility ectosymbiont of Caducaia versatilis.     

冬虫夏草菌侵染及寄生阶段的生长发育研究

冬虫夏草菌侵染进入寄主幼虫血体腔后,断裂形成长梭形的菌体。菌体以顶端出芽的方式增殖,分隔分化,互相质配。质配菌体生长出菌丝充满寄主幼虫血体腔,使幼虫死亡并形成僵虫形的菌核,菌核萌生子座即形成冬虫夏草。     

Maullinia ectocarpii gen. et sp. nov. (Plasmodiophorea), an intracellular parasite in Ectocarpus siliculosus (Ectocarpales, Phaeophyceae) and other filamentous brown algae

An obligate intracellular parasite infecting Ectocarpus spp. and other filamentous marine brown algae is described. The pathogen forms an unwalled multinucleate syncytium (plasmodium) within the host cell cytoplasm and causes hypertrophy. Cruciform nuclear divisions occur during early development. Mature plasmodia become transformed into single sporangia, filling the host cell completely, and then cleave into several hundred spores. The spores are motile with two unequal, whiplash-type flagella inserted subapically and also show amoeboid movement. Upon settlement, cysts with chitinous walls are formed. Infection of host cells is accomplished by means of an adhesorium and a stachel apparatus penetrating the host cell wall, and injection of the cyst content into the host cell cytoplasm. The parasite is characterized by features specific for the plasmodiophorids and is described as a new genus and species, Maullinia ectocarpii.     

Epimerite-host epithelium relationships among eugregarines parasitizing the damselflies Enallagma civile and Ischnura verticalis.

The host-parasite interface between 2 species of damselflies and 4 species of eugregarines was examined at the ultrastructural level. Nubenocephalus nebraskensis organisms attached to the host midgut epithelium by means of a sucker-like protomerite; the space between the epicytic folds and host epithelium was filled with electron-dense material interpreted to be adhesive in nature. Actinocephalus carrilynnae organisms attached by means of the epimerite, which had no epicytic folds, and by the fluted stalk with characteristic epicytic folds: host cell and parasite membranes appeared fused at some places on the epimerite. Hoplorhynchus acanthatholius organisms attached by means of an ovoid epimerite with backward-pointing digitations; the entire epimerite was embedded in a host cell, and host cell microvilli surrounded the stalk. Steganorhynchus dunwoodyi organisms attached by means of an ovoid stalk papilla enclosed in a retractable globular sheath; the papilla was covered with epicytic folds, but the sheath was not, and the sheath had a single membrane, whereas the epicytic folds had 2 or 3 membranes. The entire apparatus was inserted between epithelial cells, and the sheath was highly folded at its surface. The ultrastructural observations suggest that actinocephalid gregarines have evolved 2 general strategies for attaching to the host epithelium, that is, suckerlike protomerites, as in the case of N. nebraskensis, and deeply embedded epimerites inserted within or between host cells, as in the other species studied.     

中国的齿状真菌研究3.肉齿菌属

对中国肉齿菌属的3个种进行了总结,其中花状肉齿菌为中国新记录种.该种采集自海南省儋州市热带植物园,主要特征:子实体花朵状、覆瓦状叠生,囊状体棒状或纺锤形,担孢子广椭圆形.根据采集的标本对该种进行了详细的描述及显微结构绘图,对该种与其它种类的联系和区别进行了讨论,并列出了附有每种简要描述的检索表.     

Devescovinid trichomonad with axostyle-based rotary motor ("Rubberneckia"): taxonomic assignment as Caduceia versatilis sp. nov.

An amitochondriate trichomonad cell of the family Devescovinidae (Class Parabasalia), helped demonstrate the fluid model of lipoprotein cell membranes. This wood-ingesting symbiont in the hindgut of the dry wood-eating termite Cryptotermes cavifrons is informally known to cell biologists as "Rubberneckia". As the microtubular axo-style complex generates force causing clockwise movement of the entire anterior portion of the cell at the shear zone the protist displays "head" rotation. Studies by phase contrast and videomicroscopy of live cells, of whole mounts by scanning, and thin sections by transmission electron microscopy extend the observations of Tamm and Tamm [24-26] and Tamm [19-23]. Habitat, cell shape, size, nuclear features, parabasal apparatus and other morphological details permit the assignment of "Rubberneckia" to Kirby's cosmopolitan genus Caduceia. This large-sized devescovinid has distinctive parabasal gyres, an axostylar rotary, motor, and regularly-associated nonflagellated, fusiform and flagellated rod epibiotic surface bacteria. In addition to regularly aligned epibionts intranuclear and endocytoplasmic bacteria are abundant and hydrogenosomes are Present. "Rubberneckia" is compared here to the other seven species of Caduceia. Since it is clearly sufficiently distinctive to warrant new species status, we named it C. versatilis.