scholarly journals Bacillus Phage vB_BtS_B83 Previously Designated as a Plasmid May Represent a New Siphoviridae Genus

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 624 ◽  
Author(s):  
Emma G. Piligrimova ◽  
Olesya A. Kazantseva ◽  
Nikita A. Nikulin ◽  
Andrey M. Shadrin
Keyword(s):  
Electron Microscopy ◽  
Genome Organization ◽  
New Genus ◽  
Food Poisoning ◽  
Temperate Phage ◽  
Bacillus Cereus Group ◽  
Transmission Electron ◽  
Bacillus Phage ◽  
Large Terminase ◽  
Siphoviridae Family

The Bacillus cereus group of bacteria includes, inter alia, the species known to be associated with human diseases and food poisoning. Here, we describe the Bacillus phage vB_BtS_B83 (abbreviated as B83) infecting the species of this group. Transmission electron microscopy (TEM) micrographs indicate that B83 belongs to the Siphoviridae family. B83 is a temperate phage using an arbitrium system for the regulation of the lysis–lysogeny switch, and is probably capable of forming a circular plasmid prophage. Comparative analysis shows that it has been previously sequenced, but was mistaken for a plasmid. B83 shares common genome organization and >46% of proteins with other the Bacillus phage, BMBtp14. Phylograms constructed using large terminase subunits and a pan-genome presence–absence matrix show that these phages form a clade distinct from the closest viruses. Based on the above, we propose the creation of a new genus named Bembunaquatrovirus that includes B83 and BMBtp14.

scholarly journals The Genetically Remote Pathogenic Strain NVH391-98 of the Bacillus cereus Group Is Representative of a Cluster of Thermophilic Strains

2007 ◽  
Vol 74 (4) ◽  
pp. 1276-1280 ◽  
Author(s):  
Sandrine Auger ◽  
Nathalie Galleron ◽  
Elena Bidnenko ◽  
S. Dusko Ehrlich ◽  
Alla Lapidus ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Temperate Phage ◽  
Pathogenic Strain ◽  
Bacillus Cereus Group ◽  
Close Relatives

ABSTRACT Bacteria of the Bacillus cereus group are known to cause food poisoning. A rare phylogenetically remote strain, NVH391-98, was recently characterized to encode a particularly efficient cytotoxin K presumably responsible for food poisoning. This pathogenic strain and its close relatives can be phenotypically distinguished from other strains of the B. cereus group by the inability to grow at temperatures below 17°C and by the ability to grow at temperatures from 48 to 53°C. A temperate phage, phBC391A2, residing in the genome of NVH391-98 allows us to distinguish the three known members of this thermophilic strain cluster.

Taxonomy and ultrastructure of Sinerima, a new genus of diatoms (Bacillariophyta), with a description of a new species, S. marigela

Phytotaxa ◽  
2018 ◽  
Vol 351 (3) ◽  
pp. 197
Author(s):  
ANNA NESTEROVICH ◽  
BETH E. CAISSIE
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
New Species ◽  
Sea Ice ◽  
New Genus ◽  
Surface Sediments ◽  
Monotypic Genus ◽  
Transmission Electron ◽  
Spring Sea Ice ◽  
A New Species

Based on light, scanning and transmission electron microscopy observations, a detailed description of a new marine fultoportulate diatom Sinerima marigela gen. et sp. nov. is presented. This new taxa is rare (<3% of the thanatocoenosis) in surface sediments in the Bering and Chukchi seas, but appears to have an association with high spring sea ice concentrations. The new monotypic genus is distinct due to its 1) lack of rimoportulae, 2) one-layer valves with marginal pseudoloculi, 3) characteristic velum composed of a cluster of short tubes, and 4) central part without either central fultoportulae or an annulus. This set of characters, especially the lack of rimoportulae, makes S. marigela unique and easily distinguishable from other fultoportulate diatoms.

scholarly journals Genome Sequence and Characterization of Five Bacteriophages Infecting Streptomyces coelicolor and Streptomyces venezuelae: Alderaan, Coruscant, Dagobah, Endor1 and Endor2

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1065
Author(s):  
Aël Hardy ◽  
Vikas Sharma ◽  
Larissa Kever ◽  
Julia Frunzke
Keyword(s):  
Electron Microscopy ◽  
Streptomyces Coelicolor ◽  
Morphological Differentiation ◽  
Viral Diversity ◽  
Isolation And Characterization ◽  
Phage Evolution ◽  
Transmission Electron ◽  
Family Based ◽  
Siphoviridae Family

Streptomyces are well-known antibiotic producers, also characterized by a complex morphological differentiation. Streptomyces, like all bacteria, are confronted with the constant threat of phage predation, which in turn shapes bacterial evolution. However, despite significant sequencing efforts recently, relatively few phages infecting Streptomyces have been characterized compared to other genera. Here, we present the isolation and characterization of five novel Streptomyces phages. All five phages belong to the Siphoviridae family, based on their morphology as determined by transmission electron microscopy. Genome sequencing and life style predictions suggested that four of them were temperate phages, while one had a lytic lifestyle. Moreover, one of the newly sequenced phages shows very little homology to already described phages, highlighting the still largely untapped viral diversity. Altogether, this study expands the number of characterized phages of Streptomyces and sheds light on phage evolution and phage-host dynamics in Streptomyces.

A description of the testate amoeba Ovulina parva gen. nov., sp. nov. from coastal marine sediments

1996 ◽  
Vol 76 (4) ◽  
pp. 851-865 ◽  
Author(s):  
O. Roger Anderson ◽  
Andrew Rogerson ◽  
Fiona Hannah
Keyword(s):  
Electron Microscopy ◽  
Doubling Time ◽  
New Genus ◽  
Testate Amoeba ◽  
Culture Dish ◽  
Structural Morphology ◽  
Coastal Marine ◽  
Transmission Electron ◽  
Granular Matrix ◽  
Late Stages

A testate amoeba with organic test, isolated from sediments in the Firth of Clyde, Scotland, has been assigned to a new genus as Ovulina parva (Protista: Filosea) based on its unique light microscopic and fine structural morphology. The hyaline to amber test is ovate (~15×ll µm) with a terminal aperture that is either unadorned or with a shallow collar. Hyaline, long-tapering, pointed, sometimes branched, pseudopodia emerge directly from the aperture or from the periphery of a thin web of hyaline cytoplasm. The nucleus (~5 μm) with a central nucleolus (~2 μm) is located at the posterior of the cytoplasm. The fine structure of the test, examined by scanning and transmission electron microscopy, shows it is entirely organic with an irregular to granular surface. Scattered elongate pits (~1 μm long) without perforations are distributed irregularly on the surface. Ectoplasm is distributed within a fine fibrillar envelope lining the test. The endoplasm is ovoid and contains anteriorly located vacuoles enclosing densely-staining bodies with chromatin-like filaments which appear to be bacterial prey in late stages of digestion. This is further corroborated by light microscopic observations that bacteria are cleared from the surface of the culture dish within the circumference of the pseudopodia. The mitochondria (0.5–1.0 μm) have tubular cristae and some are located in the vicinity of peroxisomes (~0.5 μm) surrounded by a single membrane and with a finely granular matrix. Minimum doubling time in our cultures was 28.4 h, and the testate amoeba exhibits remarkable salinity tolerance growing in media ranging from 0 to 35% salinity.

Austrostigmidium, a new austral genus of lichenicolous fungi close to rock-inhabiting meristematic fungi in Teratosphaeriaceae

2015 ◽  
Vol 47 (3) ◽  
pp. 143-156 ◽  
Author(s):  
Sergio Pérez-Ortega ◽  
Isaac Garrido-Benavent ◽  
Asunción De Los Ríos
Keyword(s):  
Electron Microscopy ◽  
New Genus ◽  
Fungal Species ◽  
Tierra Del Fuego ◽  
Lichenicolous Fungi ◽  
Transmission Electron ◽  
The Family ◽  
Meristematic Fungi ◽  
Means Of Transmission ◽  
Host Parasite

AbstractThe new genus of lichenicolous fungi Austrostigmidium is described from Antarctica and Tierra del Fuego (Chile). It is characterized by the presence of black pseudothecia, pseudoparaphyses, fissitunicate, I−, KI− asci and 3-septate hyaline ascospores. So far, the only known species grows on Mastodia tessellata (Verrucariales, Eurotiomycetes). The new genus is compared with anatomically close genera. Based on nuLSU and nuSSU markers we inferred its phylogenetic relationships and found that it belongs to the family Teratosphaeriaceae (Capnodiales, Dothideomycetes) and is closely related to rock-inhabiting fungal species, as well as to the hyphomycetous lichenicolous fungus Xanthoriicola. Finally, the host-parasite interface has been analyzed by means of transmission electron microscopy and fluorescence microscopy in order to describe the interactions among the new fungus and the symbionts forming the host lichen.

scholarly journals Genome sequence and characterisation of coliphage vB_Eco_SLUR29

2019 ◽  
Author(s):  
Ibrahim Besler ◽  
Pavelas Sazinas ◽  
Christian Harrison ◽  
Lucy Gannon ◽  
Tamsin Redgwell ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Phylogenetic Analysis ◽  
Comparative Genomics ◽  
New Genus ◽  
Multiplicity Of Infection ◽  
Cattle Slurry ◽  
Transmission Electron ◽  
Rural England

AbstractBacteriophage that infect Escherichia coli are relatively easily isolated, with greater than 600 coliphage genomes sequenced to date. Despite this there is still much to be discovered about the diversity of coliphage genomes. Within this study we isolated a coliphage from cattle slurry collected from a farm in rural England. Transmission electron microscopy identified the phage as member of the Siphoviridae family. Phylogenetic analysis and comparative genomics further placed it within the subfamily Tunavirinae and forms part of a new genus. Characterisation of the lytic properties reveals that it is rapidly able to lyse its host when infected at high multiplicity of infection, but not at low multiplicity of infection.

Cyllamyces aberensis gen.nov. sp.nov., a new anaerobic gut fungus with branched sporangiophores isolated from cattle

2001 ◽  
Vol 79 (6) ◽  
pp. 666-673 ◽  
Author(s):  
Emin Ozkose ◽  
Barry J Thomas ◽  
David R Davies ◽  
Gareth W Griffith ◽  
Michael K Theodorou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
New Genus ◽  
The Other ◽  
Fungal Taxonomy ◽  
Dapi Staining ◽  
Free Swimming ◽  
Transmission Electron ◽  
Cattle Faeces

A new genus of the anaerobic gut fungi (Neocallimastigales), Cyllamyces aberensis gen.nov. sp.nov., with bulbous holdfast, branched sporangiophores and limited polycentric thallus development is described. The fungus was isolated from fresh cattle faeces. Free-swimming zoospores were spherical, uninucleate, and uniflagellate. After encystment, zoospores germinated and gave rise to a single, bulbous holdfast. One or several branched sporangiophores were produced from different locations on the holdfast, each bearing several spherical sporangia. DAPI staining of thalli indicated that nuclei were present in the holdfast, sporangiophores, and sporangia. As many as 12 sporangia were observed per thallus on up to 5 sporangiophores, with zoosporogenesis beginning 16–18 h after encystment. Zoospore ultrastructure was examined by transmission electron microscopy and found to be similar to that reported for other anaerobic chytrid fungi. Organelles were evenly distributed throughout the cell, except for the posteriorly attached flagellum and associated attachment apparatus, the hydrogenosomes, which were mainly situated in the posterior parts of the cell and a posteriorly directed, beak-shaped nucleus. Limited polycentric thallus development (including branched sporangiophores), the possession of a single bulbous holdfast and the absence of rhizoids were stable features of this fungus that distinguished it from the other five genera of gut fungi. Therefore, we have used these characteristics to assign the fungus to a new genus, Cyllamyces, with the specific name C. aberensis.Key words: rumen, fungal taxonomy, Neocallimastigales, chytrid, zoospore ultrastructure.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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