scholarly journals Tamsiniella labiosa gen. et sp.nov., a new freshwater ascomycete from submerged wood

1998 ◽  
Vol 76 (2) ◽  
pp. 332-337 ◽  
Author(s):  
Sze-Wing Wong ◽  
Kevin D Hyde ◽  
Wai-Hong Ho ◽  
Susan J Stanley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
New Genus ◽  
Amorphous Region ◽  
Wall Layer ◽  
Freshwater Ecosystems ◽  
Electron Microscope Level ◽  
Fibrillar Material ◽  
Transmission Electron ◽  
Characteristic Group

Investigations into the fungi occurring on wood submerged in freshwater ecosystems have revealed a unique, but characteristic group of fungi. In this paper a new pyrenomycete, Tamsiniella labiosa gen. et sp.nov., is described and illustrated with light, scanning, and transmission electron micrographs. The genus has remarkable short stipitate cylindrical asci with an internal refractive apical ring that are apically truncate and have an external thickening. Ascospores are ellipsoidal-fusiform and surrounded by a mucilaginous sheath. At the transmission electron microscope level, the annulus part of the ascus apical apparatus is differentiated from the inner ascus wall layer and is composed of horizontally oriented, electron-dense fibrillar material. A narrow plug is present in the centre of the apical ring. An electron-dense amorphous region occurs between the outer ascus wall layer and the annulus part of the apical apparatus. The outer ascus wall layer is lacking at the apex. The ultrastructure of the ascus apex differs from those described in the Lasiosphaeriaceae, Sordariaceae, and Xylariaceae.Key words: aquatic fungi, Myelosperma, new genus, transmission electron microscope.

Taxonomic studies of marine Ascomycotina: ultrastructure of the asci, ascospores, and appendages of Savoryella species

1993 ◽  
Vol 71 (2) ◽  
pp. 273-283 ◽  
Author(s):  
Susan J. Read ◽  
E. B. Gareth Jones ◽  
Stephen T. Moss
Keyword(s):  
Electron Microscope ◽  
Key Words ◽  
Transmission Electron Microscope ◽  
Outer Electron ◽  
Electron Microscope Level ◽  
Generic Level ◽  
Polar Cell ◽  
Transmission Electron ◽  
Taxonomic Studies ◽  
Electron Lucent

The asci, ascospores, and appendages of Savoryella longispora, Savoryella paucispora, and Savoryella appendiculata were examined at the transmission electron microscope level. Asci of S. longispora and S. appendiculata have a well-developed apical apparatus that consists of a thickened electron-dense ring with a central pore. In S. appendiculata the pore is occluded by a plug of electron-lucent material. The ascus wall comprises an outer narrow electron-opaque layer and an inner electron-lucent layer that are continuous over the apical apparatus. Ascospore walls possess an inner electron-lucent mesosporium and an outer electron-opaque episporium. The episporium of the central cells of all three species is covered with a layer of fibrillar mucilage. Granular strand-like outgrowths of the ascospore wall are present on the polar cells of S. appendiculata and S. paucispora. In all three species the hyaline polar cells of the ascospore contain organelles and in S. appendiculata the polar cells are verrucose. Ascospore appendages are only found in S. appendiculata and these arise endogenously by outgrowth of the endosporium of the polar cell. The differences between the three species are not considered significant at the generic level and therefore all are assigned to the genus Savoryella. Key words: appendages, Ascomycotina, ascospores, marine, taxonomy, ultrastructure.

Taxonomic studies of the Halosphaeriaceae: Ceriosporopsis, Haligena, and Appendichordella gen.nov.

1987 ◽  
Vol 65 (5) ◽  
pp. 931-942 ◽  
Author(s):  
R. G. Johnson ◽  
E. B. Gareth Jones ◽  
S. T. Moss
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Type Species ◽  
New Genus ◽  
Transmission Electron ◽  
Taxonomic Studies

Five species of Ceriosporopsis and two species of Haligena of the Halosphaeriaceae have been examined histochemically and at the scanning and transmission electron microscope levels, as part of our review of the taxonomy of marine Pyrenomycetes (Ascomycotina). Three species are retained in Ceriosporopsis: C. halima Linder (the type species), C. cambrensis Wilson, and C. tubulifera (Kohlm.) Kirk in Kohlmeyer. The genus is characterised by an outer exosporic sheath through which mucilaginous appendages are released. Great variation exists in the origin of the polar appendages and in the structure of the exosporic sheath. Only one species is retained in the genus Haligena: H. elaterophora Kohlm., while a new genus, Appendichordella, is described for Haligena amicta (Kohlm.) Kohlm. et Kohlm.

Ultrastructural observations on Nimbospora bipolaris (Halosphaeriaceae, Ascomycetes)

1993 ◽  
Vol 339 (1290) ◽  
pp. 483-489 ◽  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Microscope Level ◽  
Stages Of Development ◽  
Electron Microscope Level ◽  
Characteristic Appearance ◽  
Mucilaginous Sheath ◽  
Early Stages ◽  
Transmission Electron

The ultrastructure of the ascus, ascospores and appendages of Nimbospora bipolaris were examined at the transmission electron microscope level. The mature ascus wall comprises a single narrow electron-opaque layer which deliquesces and lacks an apical elaboration. Ascospore walls comprise a bipartite mesosporium, a thinner electron-opaque episporium and an outer mucilaginous sheath. Before release from the ascus the mucilaginous sheath is compact and folded. The fibrillar, trailing ascospore appendages are arranged in eight equidistant tufts around the circumference of the septum, originate from the mesosporium and emerge through pores in the episporium. In early stages of development the appendages are retained within the mucilaginous sheath but upon release from the ascus the sheath expands and the appendages pierce the sheath and radiate out to form their characteristic appearance. Ascospore ontogeny in N. bipolaris is compared with other appendaged members of the Halosphaeriaceae.

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens

1969 ◽  
Vol 27 ◽  
pp. 176-177 ◽  
Author(s):  
H. Tochigi ◽  
H. Uchida ◽  
S. Shirai ◽  
K. Akashi ◽  
D. J. Evins ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
High Excitation ◽  
Transmission Electron ◽  
New Instrument

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

A General Method for Spectrometer Design in the Scoff Approximation

1976 ◽  
Vol 34 ◽  
pp. 538-539
Author(s):  
J. R. Fields
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Energy Analysis ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Chemical Identification ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
General Method

The energy analysis of electrons scattered by a specimen in a scanning transmission electron microscope can improve contrast as well as aid in chemical identification. In so far as energy analysis is useful, one would like to be able to design a spectrometer which is tailored to his particular needs. In our own case, we require a spectrometer which will accept a parallel incident beam and which will focus the electrons in both the median and perpendicular planes. In addition, since we intend to follow the spectrometer by a detector array rather than a single energy selecting slit, we need as great a dispersion as possible. Therefore, we would like to follow our spectrometer by a magnifying lens. Consequently, the line along which electrons of varying energy are dispersed must be normal to the direction of the central ray at the spectrometer exit.

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