Snake tongue-flicking: transfer mechanics to Jacobson's organ

1981 ◽  
Vol 59 (9) ◽  
pp. 1651-1657 ◽  
Author(s):  
James C. Gillingham ◽  
David L. Clark
Keyword(s):  
Vomeronasal Organ ◽  
Electron Microscopic Examination ◽  
Ventral Surface ◽  
Tongue Flick ◽  
Garter Snakes ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Food Odors ◽  
Tongue Flicking ◽  
Jacobson's Organ

Cinematographic analysis of the open-mouthed tongue flick of rat snakes (Elaphe) revealed elevation of the anterior processes following tongue retraction into the lingual sheath. The ventral surface of the tongue makes contact with these processes on each retraction and these processes are directly aligned with Jacobson's (vomeronasal) organ in the roof of the mouth. Scanning electron microscopic examination of the anterior process surface reveals an increased surface area through oblique ridges. Experimental removal of these structures prevents open-field detection of food odors in garter snakes (Thamnophis). These data indicate that this structure is the vehicle for transfer of substances to Jacobson's organ during snake chemosensation.

A Comparative Study of Fractographic Replicas

1974 ◽  
Vol 32 ◽  
pp. 566-567
Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon
Keyword(s):  
Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Direct Examination ◽  
Electron Microscopic ◽  
Reliable Technique ◽  
Service Failures ◽  
Transmission Electron ◽  
Mode Of Failure ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.

Cell interactions of Listeria monocytogenes L forms and peritoneal exudative cells in rats

1993 ◽  
Vol 39 (11) ◽  
pp. 1014-1021 ◽  
Author(s):  
L. Mihailova ◽  
N. Markova ◽  
T. Radoucheva ◽  
D. Veljanov ◽  
S. Radoevska
Keyword(s):  
Listeria Monocytogenes ◽  
Peritoneal Cavity ◽  
Electron Microscopic Examination ◽  
Lavage Fluid ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cellular Defense ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Listeria monocytogenes 4b and its forms without cell walls (L forms of a protoplastic type) were used to study in vivo interactions with host cells. Samples of peritoneal lavage fluid were obtained from rats intraperitoneally inoculated at intervals between 1 and 15 days after challenge, for scanning electron microscopic, bacteriological, biochemical, and cytometrical investigations. Scanning electron microscopic examination revealed continuous adhesion of L forms on the macrophage surface up to 15 days after inoculation. The persistence of the L forms within the peritoneal cavity was also shown bacteriologically at all sample times, while the parental bacterial forms were isolated from the peritoneal cavity up to 7 days after challenge. The total count of peritoneal exudative cells determined by automated flow peroxidase cytometry peaked on the 15th day in animals infected with parental forms, while in animals infected with L forms the peak was lower and the macrophage population was predominant. The glycolytic and acid phosphatase activity of peritoneal exudative cells was two times higher in rats infected with L forms as compared with rats infected with the L. monocytogenes parental forms on the 3rd day after challenge. An understanding of the nature of the interactions between L forms of L. monocytogenes and peritoneal exudative cells found in vivo could be used to establish the influence of L forms on host cellular defense mechanisms.Key words: Listeria monocytogenes, L forms, peritoneal exudative cells, electron microscopy.

A comparison of the effects of several antifungal imidazole derivatives and polyenes on Candida albicans: an ultrastructural study by scanning electron microscopy

1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cytoplasmic Membrane ◽  
Electron Microscopic Examination ◽  
Yeast Cells ◽  
Electron Microscopic ◽  
Imidazole Derivatives ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.

Analysis of non-morphometric morphological characters used in the taxonomy of the genus Pseudechiniscus (Tardigrada: Echiniscidae)

2019 ◽  
Author(s):  
Denis V Tumanov
Keyword(s):  
Species Delimitation ◽  
Taxonomic Status ◽  
Electron Microscopic Examination ◽  
Morphological Characters ◽  
Electron Microscopic ◽  
The Family ◽  
Scanning Electron Microscopic ◽  
Claw Morphology ◽  
Taxonomic Studies ◽  
A New Species

Abstract Pseudechiniscus, the second-largest genus of the family Echiniscidae (Tardigrada: Heterotardigrada: Echiniscoidea), is notoriously difficult for taxonomic studies. In this study, I performed a morphological analysis of a new species from Croatia, based on a light microscopic and scanning electron microscopic examination of 45 specimens from the same sample. Furthermore, I have summarized all available data on Pseudechiniscus species, including their original descriptions, and have analysed the following complexes of morphological characters: (1) arrangement and morphology of dorsal cuticular plates, (2) ventral sculpture, (3) morphology of cephalic, trunk and leg sensory organs and (4) claw morphology. The applicability of these characters in the taxonomy and their distribution in the genus are discussed. Some of the characters traditionally used for species delimitation were shown to be unsuitable and others in need of a thorough reinvestigation. The meaning of the old term ‘faceted’, commonly used but often misapplied, has been clarified, based on the initial definition. Several characters of the claw structure were suggested as potentially useful for species delimitation. The taxonomic status of several old forms and species was discussed.

Scanning electron microscope examination of the dental enameloid of the Cretaceous durophagous shark Ptychodus supports neoselachian classification

2016 ◽  
Vol 90 (4) ◽  
pp. 741-762 ◽  
Author(s):  
Brian L. Hoffman ◽  
Scott A. Hageman ◽  
Gregory D. Claycomb
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Microscopic Examination ◽  
Middle Layer ◽  
Microscope Examination ◽  
Electron Microscopic ◽  
Marine Deposits ◽  
Scanning Electron Microscopic ◽  
Greenhorn Formation ◽  
Scanning Electron

AbstractAlthough Ptychodus teeth are well known in Late Cretaceous marine deposits in North America and Europe and a few specimens with jaw elements have been discovered, the taxonomic position of the shark genus Ptychodus is enigmatic due to the lack of preservation of diagnostic material other than teeth. These sharks possessed a pavement dentition suited to a diet of hard-shelled macroinvertebrates (durophagy), leading several studies to variously describe Ptychodus as a batoid, a hybodont shark, or a selachimorph. Members of the Selachimorpha share one dental synapomorphy, a triple-layered enameloid (TLE) consisting of an outer shiny-layered enameloid (SLE) of randomly oriented hydroxyapatite crystallites, a middle layer of parallel-bundled enameloid (PBE), and an inner layer of tangled-bundled enameloid (TBE). Batoids and hybodonts both have teeth with single crystallite enameloid (SCE). We examined teeth from Ptychodus collected from the Lincoln Limestone of the Greenhorn Formation of Barton County, Kansas, and compared their enameloid ultrastructure with that of a Carboniferous hybodontiform and the Cretaceous lamniform shark Squalicorax curvatus Williston, 1900. Scanning electron microscopic examination of Ptychodus shows that crystallite bundling in the form of a TLE is evident in these teeth. The PBE is most apparent at transverse enameloid ridges of Ptychodus teeth. Columns of dentine penetrate into the tooth enameloid, and the crystallites near the dentine are randomly oriented. These observations bolster the argument that Ptychodus is a genus of highly specialized selachimorph shark, rather than a hybodont or batoid.

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