scholarly journals Morphological and Molecular Characterization of Toxocara apodemi (Nematoda: Ascarididae) from Striped Field Mice, Apodemus agrarius, in Korea

2020 ◽  
Vol 58 (4) ◽  
pp. 403-411
Author(s):  
Hyeon Cheol Kim ◽  
Eui Ju Hong ◽  
Si Yun Ryu ◽  
Jinho Park ◽  
Jeong Gon Cho ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
18S Rrna ◽  
Rrna Gene ◽  
Scanning Electron Micrographs ◽  
Toxocara Cati ◽  
Apodemus Agrarius ◽  
Toxocara Vitulorum ◽  
Field Mice ◽  
Scanning Electron

Adult ascarid worms from the field mice, Apodemus agrarius, were observed with a light and scanning electron microscope, and molecularly analized with 18S rRNA gene. In the scanning electron microscope, 3 prominent labia were present in the anterior end of male and female worms, but the interlabia and gubernaculum were absent. Scanning electron micrographs showed cervical alae as vestigial organs that looked like a slightly uplifted superficial sewing stitch. Total 6 pairs of post-cloacal papillae were observed on the tail of the male worms. The tail of female worms was blunt and conical shape with a spine-like structure, mucron. The eggs were sub-globular, coated with the albuminous layer and 73 by 82 μm in average size. The superficial pits of T. apodemi egg (mean 8.6×6.7 μm) are obviously bigger than those of Toxocara spp. The partial sequence of 18S rRNA showed the sequence homology of Toxocara canis (99.6%), Toxocara cati (99.4%), Toxascaris leonina (99.4%), and Toxocara vitulorum (99.2%). Conclusively, it was confirmed that ascarid nematodes, Toxocara apodemi, recovered from striped field mice in Korea are taxonomically conspecific relationship with genus Toxocara and genetic divergence from other Toxocara species.

scholarly journals Studies in Oberonia, 9: Lessons from excess names in Oberonia for Orchidaceae systematics, including a revision of the Oberonia Sect. Scytoxiphium

Lankesteriana ◽  
2021 ◽  
Author(s):  
Daniel L. Geiger
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
21St Century ◽  
Expert Advice ◽  
Scanning Electron Micrographs ◽  
Palabras Clave ◽  
Microscope Images ◽  
Typological Thinking ◽  
Scanning Electron

The reasons for excess names in microfloral orchids such as Oberonia Lindl. can be traced to poor scholarship (e.g., failure to review the literature, ignoring expert advice), typological thinking, and erroneous assumption of microendemism. Some extraordinarily poor descriptions, including some from the 21st century, can be termed “taxonomic vandalism”. The outdated reliance on drawings as opposed to z-stacked photographs and scanning electron micrographs poses further problems due to an abundance of demonstrable problems with drawings. The Oberonia sect. Scytoxiphium Schltr. with eight described species is reduced to one species, Oberonia heliophila Rchb.f.; it is illustrated by original drawings, live photographs and scanning electron microscope images. The distribution is extended from Java through Micronesia and Samoa. The species occurs predominantly from 0–500 m, less frequently to 900 m, and possibly to even 1900 m. It flowers throughout the year. Keywords/Palabras clave: Oberonia, Oberonia sect. Scytoxiphium, revision, revisión, synonymies, sinonimias, taxonomic vandalism, vandalismo taxonómico

The microstructure of the dentition and dermal ornament of three dipnoans from the Devonian of Western Australia: a contribution towards dipnoan interrelations, and morphogenesis, growth and adaption of the skeletal tissues

1977 ◽  
Vol 281 (979) ◽  
pp. 29-72 ◽  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Anterior Part ◽  
Polarized Light ◽  
Scanning Electron Micrographs ◽  
Dental Tissues ◽  
Functional Surfaces ◽  
Current Usage ◽  
First Time ◽  
Scanning Electron

Detailed descriptions of the microstructure, which includes both histology and ultrastructure, are given for each type of tissue in each of the three species of Australian dipnoan. Most of the tissues have not previously been recorded in this way even for other species within the same genera. The microstructure is interpreted from examination of ground sections in transmitted and polarized light, together with examination of functional, forming and fracture surfaces in the scanning electron microscope. No previous studies of dipnoan dental tissues have been published in which the histology is related to surface morphology as seen in the scanning electron microscope. The histology, microstructure, growth and distribution of buccal denticles are described in Griphognathus whitei and Holodipterus gogoensis , and their morphogenesis and adaptation to function is discussed. It is concluded that the phyletic trend towards macromerism, as shown in chondricthyans and primitive teleostomes, is illustrated in the three species of dipnoan. The continuous layer of dentine of the tooth ridges, lips and covering to the dermal snout is described and found to be similar in the three species and equivalent to the tissue described previously in other dipnoans, sometimes as a form of cosmine. A term not in current usage is suggested for this dentine, namely syndentine. Dentine terminology is reviewed and the relevance to dipnoan dental tissues is discussed with the conclusion that an older term should be reintroduced to eliminate the current anomalies in terminology. Chirodipterus australis is the only species with typical tooth plates. The histology is compared with previous accounts of tooth plates in dipnoans and found to have some similarity with those of Neoceratodus forsteri . The microstructure is reported from examination of the worn functional surfaces and acid-etched functional surfaces with the scanning electron microscope, this information has not previously been reported for dipnoan tooth plates and is presented here as a basis for comparison with other species. New features of cosmine structure are described from scanning electron micrographs of the surfaces and these are related to the probable mode of formation and the involvement of the epithelial cells. The structure is found to compare in some ways with the cosmine of osteolepids. The loss of cosmine and replacement by tubercles in Griphognathus whitei and Holodipterus gogoensis is explained as retention of an ontogenetic potential which is comparable with Ørvig’s theory of cosmine regression in the porolepids. Superpositional growth in the dermal skull bones is described for the first time in dipnoans. It is postulated that the ancestors of dipnoans had superimposed denticles beneath a cosmine covering. The information obtained from the microstructure is used to examine the hypothesis proposed by Miles (1977) in a paper on the phyletic relations within the dipnoans. This confirms that Griphognathus white i has retained a primitive dentition with separate buccal denticles and tooth ridges; Holodipterus gogoensis has retained these features, denticles and lip ridges, together with an advanced feature of tooth cusps which are a divergent specialization phyletically preceding tooth plates; Chirodipterus australis has not retained buccal denticles but has lip ridges on the snout and anterior part of the lower jaw, and the specialized tooth plates. Pleromic dentine is recorded in two of these species and discussed with other observed methods of adaptation to wear.

Cell walls in Cucurbita maxima cotyledons in relation to imbibition

1974 ◽  
Vol 52 (7) ◽  
pp. 1465-1468 ◽  
Author(s):  
John N. A. Lott
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
Propylene Oxide ◽  
Cell Walls ◽  
Scanning Electron Micrographs ◽  
Cucurbita Maxima ◽  
Glutaraldehyde Fixation ◽  
Mesophyll Cells ◽  
Scanning Electron

The scanning electron microscope and the freeze-etch technique were used to demonstrate the presence of corrugated cell walls in cotyledon mesophyll cells from dry squash seeds. These wavy cell walls straightened out during imbibition. In the scanning electron micrographs no wavy cell walls were observed in the smaller epidermal cells. Tissue imbibed for 2 h and then air-dried contained corrugated cell walls, whereas similar imbibed tissue dehydrated in ethanol and propylene oxide contained smooth cell walls. Thus the method of seed dehydration is important in determining the appearance of wavy cell walls. Glutaraldehyde fixation during the 2-h imbibition process did not alter the conditions under which wavy cell walls reappear.

PROPERTIES OF TWO FRAGIPAN SOILS IN NOVA SCOTIA INCLUDING SCANNING ELECTRON MICROGRAPHS

1974 ◽  
Vol 54 (2) ◽  
pp. 159-170 ◽  
Author(s):  
CHANG WANG ◽  
J. L. NOWLAND ◽  
H. KODAMA
Keyword(s):  
Electron Microscope ◽  
Nova Scotia ◽  
Hydraulic Conductivity ◽  
Scanning Electron Microscope ◽  
Clay Fraction ◽  
Fine Sand ◽  
Scanning Electron Micrographs ◽  
Moderate Amount ◽  
High Bulk ◽  
Scanning Electron

About 250,000 acres of soil with fragipan have been mapped in Nova Scotia. The fragipan horizons of two soils (Tormentine and Debert) reported in this paper are typical for the province. They have high bulk densities and low saturated hydraulic conductivity. They are also low in organic carbon and free oxides. They are high in fine sand and silt but low in clay, and the fragments of fragipan are readily slaked in water. Mica, chlorite, vermiculite, and kaolinite were found in the clay fractions of both soils throughout the two profiles. A moderate amount of smectite was found in the clay fractions of the Ae horizon of Debert but not in the Tormentine profile. A significant amount of clay increase in both fine and total clay fraction was found in the Bf horizon of the Tormentine soil and the Bmgj and Btx horizons of the Debert soil, and results from translocation or lessivage. The brittleness and other associated properties of the fragipans were attributed to clay bridges linking coarser particles, which were shown in the scanning electron microscope pictures.

An SEM study of the cephalic region, buccal cavity and male tail of the species of the genus Strongylus Müller, 1780 (Nematoda, Strongyloidea)

1984 ◽  
Vol 58 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Lynda M. Gibbons
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
Buccal Cavity ◽  
Scanning Electron Micrographs ◽  
Specific Identification ◽  
Male Tail ◽  
Genital Cone ◽  
Sem Study ◽  
Scanning Electron

AbstractThe four species of the genus Strongylus Müller, 1780, namely, S. equinus, S. edentatus, S. vulgaris and S. asini were examined with the scanning electron microscope (SEM). The buccal cavity of each species was cut transversely and longitudinally and the scanning electron micrographs illustrate the shape of the buccal cavity and the dorsal gutter. The micrographs also show the presence of denticles near the oral rim of the buccal cavity of S. edentatus and the shape of the teeth in the buccal cavity of S. equinus, S. vulgaris and S. asini. The bursa of the four species has three symmetrical lobes, one dorsal and two lateral. The length of the three lobes in relation to each other varies between the species. The genital cone has a single large ventral papilla, a pair of dorsal raylets, a median dorsal cuticular appendage and a variety of cuticular appendages lateral and ventral to the cloaca. The development and arrangement of these components differs between the four species of the genus and can be used as a supportive character for specific identification.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 386-387
Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Image ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.

Characterization of Sputtered Films using the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 44-45
Author(s):  
R. F. Schneidmiller ◽  
W. F. Thrower ◽  
C. Ang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Sputtered Films ◽  
Plasma Sputtering ◽  
Microelectronic Devices ◽  
Control Film ◽  
Scanning Electron

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.

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