scholarly journals Review of the Capsalinae (Monogenea: Capsalidae)

Zootaxa ◽  
2007 ◽  
Vol 1559 (1) ◽  
pp. 1-30 ◽  
Author(s):  
LESLIE A. CHISHOLM ◽  
IAN D. WHITTINGTON
Keyword(s):  
Ventral Surface ◽  
Current Concept ◽  
Specimen Preparation ◽  
Reproductive Structures ◽  
The Status ◽  
Voucher Specimens ◽  
Preparation Techniques ◽  
Species Inquirendae

The Capsalinae Baird, 1853 (Monogenea: Capsalidae) is revised based on a thorough review of original descriptions and examination of type museum material, where available, to validate species. A total of 262 type and voucher specimens was studied representing apparently 42 of the 60 currently described capsaline species. A combination of characters that should be independent of variation due to specimen preparation techniques was chosen to discriminate species. These characters include the presence/absence of papillae on the ventral surface of the haptor, the presence/absence and the morphology of haptoral accessory sclerites and the presence/absence of dorsomarginal body sclerites and their morphology and distribution. We consider that only 36 of the 60 nominal capsaline species are valid. We could find no support for Caballerocotyla Price, 1960 and therefore we synonymise it with Capsala Bosc, 1811. Under the current concept we recognise 22 species of Capsala, 7 species of Capsaloides Price, 1938, 3 species of Nasicola Yamaguti, 1968 and 4 species of Tristoma Cuvier, 1817. The following Capsala species are considered valid: C. albsmithi (Dollfus, 1962) n. comb.; C. biparasitica (Goto, 1894) Price, 1938; C. caballeroi Winter, 1955; C. foliacea (Goto, 1894) Price, 1938; C. gouri Chauhan, 1951; C. gregalis (Wagner & Carter, 1967) n. comb.; C. interrupta (Monticelli, 1891) Johnston, 1929; C. katsuwoni (Ishii, 1936) Price, 1938; C. laevis (Verrill, 1875) Johnston, 1929; C. maccallumi Price, 1939; C. magronum (Ishii, 1936) Price, 1938; C. manteri Price, 1951; C. manteriaffinis (Mamaev, 1968) n. comb.; C. martinierei Bosc, 1811; C. notosinense (Mamaev, 1968) n. comb.; C. nozawae (Goto, 1894) Price, 1938; C. onchidiocotyle (Setti, 1899) Johnston, 1929; C. ovalis (Goto, 1894) Price, 1938; C. paucispinosa (Mamaev, 1968) n. comb.; C. pelamydis (Taschenberg, 1878) Price, 1938; C. poeyi (Pérez-Vigueras, 1935) Price, 1938; C. pricei Hildago-Escalente, 1950. We consider the following Capsaloides species valid: C. cornutus (Verrill, 1875) Price, 1938; C. cristatus Yamaguti, 1968; C. hoffmannae Lamothe-Argumedo, 1996; C. magnaspinosus Price, 1939; C. nairagi Yamaguti, 1968; C. perugiai (Setti, 1898) Price, 1938; C. sinuatus (Goto, 1894) Price, 1938. The following Nasicola species are deemed valid: N. brasiliensis Kohn, Baptista-Farias, Santos & Gibson, 2004; N. hogansi Wheeler & Beverley-Burton, 1987; N. klawei Stunkard, 1962. Presently, we consider the following Tristoma species valid: T. adcoccineum Yamaguti, 1968; T. adintegrum Yamaguti, 1968; T. coccineum Cuvier, 1817; T. integrum Diesing, 1850. A list of new and re-established synonyms is provided. The status of each species is discussed in detail and a key to all capsaline species that we consider valid is presented. The following 5 capsaline species are considered to be species inquirendae: Caballerocotyla phillippina Velasquez, 1982; Capsala megacotyle (Linstow, 1906) Johnston, 1929; Tristoma fuhrmanni Guiart, 1938; T. levinsenii Monticelli, 1891; T. uncinatum Monticelli, 1889. The importance of careful character selection to discriminate between capsaline species and the need for studies of live parasites to obtain additional characters based on reproductive structures is addressed. Hostspecificity in the Capsalinae is also discussed.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

Electron Microscopic Observation of Biological Specimens in Their Native State by Employing Cryogenic Techniques

1972 ◽  
Vol 30 ◽  
pp. 410-411 ◽  
Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa
Keyword(s):  
Electron Microscopic Observation ◽  
Surface Structures ◽  
Specimen Preparation ◽  
Native State ◽  
Electron Microscopic ◽  
Biological Specimen ◽  
Specimen Holder ◽  
Cold Stage ◽  
Preparation Techniques ◽  
Scanning Electron

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.

Electron Microscopy of Bacteriophage T7 Internal Head Proteins

1975 ◽  
Vol 33 ◽  
pp. 638-639
Author(s):  
P. Serwer
Keyword(s):  
Electron Microscopy ◽  
Bacteriophage T7 ◽  
Specimen Preparation ◽  
Dna Molecule ◽  
The Core ◽  
Internal Core ◽  
Phage T7 ◽  
T7 Phage ◽  
Preparation Techniques ◽  
Internal Head

The genome of bacteriophage T7 is a duplex DNA molecule packaged in a space whose volume has been measured to be 2.2 x the volume of the B form of T7 DNA. To help determine the mechanism for packaging this DNA, the configuration of proteins inside the phage head has been investigated by electron microscopy. A core which is roughly cylindrical in outline has been observed inside the head of phage T7 using three different specimen preparation techniques.When T7 phage are treated with glutaraldehyde, DNA is ejected from the head often revealing an internal core (dark arrows in Fig. 1). When both the core and tail are present in a particle, the core appears to be coaxial with the tail. Core-tail complexes sometimes dislodge from their normal location and appear attached to the outside of a phage head (light arrow in Fig. 1).

Comparison of freeze-fractured yeast replicas using conventional TEM and low-voltage field-emission SEM

1989 ◽  
Vol 47 ◽  
pp. 74-75
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Terrence W. Reilly
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Lens System ◽  
Air Drying ◽  
Preparation Techniques ◽  
Scanning Electron

Although the first commercial scanning electron microscope (SEM) was introduced in 1965, the limited resolution and the lack of preparation techniques initially confined biological observations to relatively low magnification images showing anatomical surface features of samples that withstood the artifacts associated with air drying. As the design of instrumentation improved and the techniques for specimen preparation developed, the SEM allowed biologists to gain additional insights not only on the external features of samples but on the internal structure of tissues as well. By 1985, the resolution of the conventional SEM had reached 3 - 5 nm; however most biological samples still required a conductive coating of 20 - 30 nm that prevented investigators from approaching the level of information that was available with various TEM techniques. Recently, a new SEM design combined a condenser-objective lens system with a field emission electron source.

Status of Family Fissidentaceae in Gujarat

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar
Keyword(s):  
Distinct Species ◽  
The State ◽  
The Other ◽  
Land Plants ◽  
Reproductive Structures ◽  
The Family ◽  
The Status ◽  
Vegetative Characters ◽  
First Time ◽  
Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

scholarly journals Vapor Coating: A Simple, Economical Procedure for Preparing Difficult Specimens for Scanning Electron Microscopy

2007 ◽  
Vol 15 (3) ◽  
pp. 44-45 ◽  
Author(s):  
E. Ann Ellis ◽  
Michael W. Pendleton
Keyword(s):  
Osmium Tetroxide ◽  
Petri Dish ◽  
Specimen Preparation ◽  
Fume Hood ◽  
Imaging Center ◽  
User Facility ◽  
Small Container ◽  
Set Up ◽  
Preparation Techniques ◽  
Scanning Electron

The Microscopy and Imaging Center at Texas A&M University is a multi-user facility involved with preparation and analysis of many different biological and materials sciences projects. Vapor stabilization and coating is an important part of our specimen preparation methodology for difficult biological and materials, especially polymer, samples. The procedure for all our vapor preparation techniques is done in a simple, economical apparatus set up in a properly functioning fume hood with a flow rate of at least 100 ft/min (Fig. 1). The apparatus is made from a glass petri dish or a glass petri dish for the bottom and an appropriate size beaker for the top. Specimens, mounted on stubs, are placed inside the chamber and the fixative (osmium tetroxide, ruthenium tetroxide or acrolein) is placed in a small container (plastic bottle cap) near the specimens.

Characterization of FIB Damage in Silicon

1999 ◽  
Vol 5 (S2) ◽  
pp. 740-741 ◽  
Author(s):  
C.A. Urbanik ◽  
B.I. Prenitzer ◽  
L.A. Gianhuzzi ◽  
S.R. Brown ◽  
T.L. Shofner ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Target Material ◽  
Beam Current ◽  
Specimen Preparation ◽  
Transfer Energy ◽  
Transmission Electron ◽  
Preparation Techniques ◽  
Reactive Gas

Focused ion beam (FIB) instruments are useful for high spatial resolution milling, deposition, and imaging capabilities. As a result, FIB specimen preparation techniques have been widely accepted within the semiconductor community as a means to rapidly prepare high quality, site-specific specimens for transmission electron microscopy (TEM) [1]. In spite of the excellent results that have been observed for both high resolution (HREM) and standard TEM specimen preparation applications, a degree of structural modification is inherent to FIB milled surfaces [2,3]. The magnitude of the damage region that results from Ga+ ion bombardment is dependent on the operating parameters of the FIB (e.g., beam current, beam voltage, milling time, and the use of reactive gas assisted etching).Lattice defects occur as a consequence of FIB milling because the incident ions transfer energy to the atoms of the target material. Momentum transferred from the incident ions to the target atoms can result in the creation of point defects (e.g., vacancies, self interstitials, and interstitial and substitutional ion implantation), the generation of phonons, and plasmon excitation in the case of metal targets.

Applying Dynamic Experiments and Stereo Measurements to Evaluation of Dentin Specimen Preparation Techniques for Environmental and Conventional SEM

2000 ◽  
Vol 6 (S2) ◽  
pp. 782-784
Author(s):  
V.M. Dusevich ◽  
J.D. Eick
Keyword(s):  
Water Vapor Pressure ◽  
Water Layer ◽  
Dental Composite ◽  
Specimen Preparation ◽  
Drying Process ◽  
Excess Water ◽  
Dynamic Experiments ◽  
Thickness Measurements ◽  
Preparation Techniques ◽  
Environmental Sem

The acid etching process is the primary stage for preparation of dental composite restorations. Dentin specimens from extracted teeth are usually prepared by fracturing etched pieces of dentin. Etching creates a demineralized layer on the dentin surface with the thickness of a few microns. The layer consists of wet collagen and dissolved proteins; its drying process is of special interest in dentistry since it affects the bonding of the resin adhesives to dentin. Observations of fractured surfaces can be performed in either a conventional or an environmental SEM.Three wet dentin samples were observed (XL30 FEG ESEM, FEI/Philips) in wet mode at 5°C Peltier cooling stage temperature and 5.8 MPa water vapor pressure. Samples with excess water on their top surface were put in an ESEM. Thickness measurements of the demineralized zone were begun immediately after the evaporation of this water layer with subsequent measurements taken after 5, 10, 20, 40, 60 and 100 minutes of drying.

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