scholarly journals Structural colours in diverse Mesozoic insects

2020 ◽  
Vol 287 (1930) ◽  
pp. 20200301
Author(s):  
Chenyang Cai ◽  
Erik Tihelka ◽  
Yanhong Pan ◽  
Ziwei Yin ◽  
Rixin Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Theoretical Modelling ◽  
Ecological Interactions ◽  
Geological Time ◽  
Exceptional Preservation ◽  
Transmission Electron ◽  
Bluish Green ◽  
Preservation Potential ◽  
Electron Lucent

Structural colours, nature's most pure and intense colours, originate when light is scattered via nanoscale modulations of the refractive index. Original colours in fossils illuminate the ecological interactions among extinct organisms and functional evolution of colours. Here, we report multiple examples of vivid metallic colours in diverse insects from mid-Cretaceous amber. Scanning and transmission electron microscopy revealed a smooth outer surface and five alternating electron-dense and electron-lucent layers in the epicuticle of a fossil wasp, suggesting that multilayer reflectors, the most common biophotonic nanostructure in animals and even plants, are responsible for the exceptional preservation of colour in amber fossils. Based on theoretical modelling of the reflectance spectra, a reflective peak of wavelength of 514 nm was calculated, corresponding to the bluish-green colour observed under white light. The green to blue structural colours in fossil wasps, beetles and a fly most likely functioned as camouflage, although other functions such as thermoregulation cannot be ruled out. This discovery not only provides critical evidence of evolution of structural colours in arthropods, but also sheds light on the preservation potential of nanostructures of ancient animals through geological time.

In situ silicification of an Icelandic hot spring microbial mat: implications for microfossil formation

1995 ◽  
Vol 32 (12) ◽  
pp. 2021-2026 ◽  
Author(s):  
S. Schultze-Lam ◽  
F. G. Ferris ◽  
K. O. Konhauser ◽  
R. G. Wiese
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hot Spring ◽  
Microbial Mat ◽  
Chloroflexus Aurantiacus ◽  
X Ray ◽  
Exceptional Preservation ◽  
Transmission Electron ◽  
Nucleation Sites

Transmission electron microscopy and energy-dispersive x-ray analysis revealed that filamentous phototrophic bacteria resembling Chloroflexus aurantiacus underwent rapid silicification in an Icelandic hot spring microbial mat. The mineralization associated with the cells occurred both extracellularly, within and on the external sheaths of the bacteria, and intracellularly, within the cytoplasm. The exceptional preservation of the bacterial sheaths is due to the presence of distinct mineral nucleation sites. This results in the production of silica casts of the bacteria, which bear a striking resemblance to microbial remains in ancient microfossil assemblages.

The comparative ultrastructure of spermatozoa from Bothrimonus sturionis Duv. 1842 (Pseudophyllidea), Pseudanthobothrium hanseni Baer, 1956 (Tetraphyllidea), and Monoecocestus americanus Stiles, 1895 (Cyclophyllidea)

1984 ◽  
Vol 62 (6) ◽  
pp. 1059-1066 ◽  
Author(s):  
Barbara M. MacKinnon ◽  
Michael D. B. Burt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plasma Membrane ◽  
Main Body ◽  
Posterior Portion ◽  
Transmission Electron ◽  
Dense Nucleus ◽  
Comparative Ultrastructure ◽  
Electron Lucent ◽  
Mature Spermatozoa

The mature spermatozoa from Bothrimonus sturionis (Pseudophyllidea), Pseudanthobothrium hanseni (Tetraphyllidea), and Monoecocestus americanus (Cyclophyllidea) were examined using transmission electron microscopy. Transverse sections of the sperm of B. sturionis indicate that the number of sperm axonemes varies from one to eight, with approximately one-third of the sperm containing two axonemes. Likewise, the number of peripheral microtubules lying just within the external plasma membrane varies from 12 to 20. The nucleus is electron lucent and fibrous in appearance. The spermatozoa of B. sturionis show great variation in the material examined and the majority of them are believed to be aberrant. The spermatozoon of P. hanseni contains a single axoneme with the nucleus wrapped in a crescent around it in the anterior region of the sperm. The posterior portion of the spermatozoon is characterized by a helical flange which projects from the main body of the sperm. The spermatozoon of M. americanus is elongate and slender, containing a single axoneme with an electron-dense nucleus coiled around it in the anterior one-third of the sperm. Electron-opaque bodies, which may be glycogen, fill the cytoplasm. The spermatozoa of all three species contain neither an acrosome nor mitochondria. The flagella of all the spermatozoa have a 9 + "1" arrangement of microtubules. The importance of the ultrastructure of spermatozoa in the phylogeny and taxonomy of cestodes is discussed.

Vitellocyte ultrastructure in the cestode Didymobothrium rudolphii (Monticelli, 1890): possible evidence for the recognition of divergent taxa within the Spathebothriidea

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Larisa Poddubnaya ◽  
David Gibson ◽  
Zdzisław Świderski ◽  
Peter Olson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lipid Droplets ◽  
Interstitial Tissue ◽  
Morphological Parameters ◽  
Transmission Electron ◽  
Shell Globule ◽  
Didymobothrium Rudolphii ◽  
First Time ◽  
Electron Lucent

AbstractIn the spathebothriidean tapeworm Didymobothrium rudolphii (Monticelli, 1890) the fine structure of the vitellocytes at different stages of their development within the vitelline follicles, vitelline ducts and uterus was studied for the first time using transmission electron microscopy. The vitellocyte inclusions of D. rudolphii are shell globule clusters containing tightly packed shell globules associated with a matrix of moderate electron density, glycogen granules, large electron-lucent lipid droplets (up to 3 μm in diameter), and, occasionally, a lipid droplet may occur in the nucleus of the vitellocytes. The diameter of the clusters ranges from 0.4 to 2.5 μm, the number of shell globules in the clusters varies from 8 to 45, and the size of the globules ranges from 0.12 to 0.25 μm and they are of approximately homogeneous sizes within a cluster. Most vitellocyte lipid droplets have a heterogeneous configuration with a ‘cavity’ inside them when they are within vitelline ducts and intrauterine eggs. Vitellocytes of the eggs contain dark concentric bodies and lipid droplets. The interstitial tissue has a syncytial structure. The morphological parameters of the diameter and shape of shell globule clusters, arrangement of shell globules in clusters, number and diameter of globules within clusters, types of lipid droplets and presence of dark concentric bodies are compared with those of two other spathebothriidean genera, Cyathocephalus and Diplocotyle. The comparative data demonstrate that vitelline material morphology has unique features in three spathenothriidean genera and may be used as evidence for the recognition of separate taxa.

Ultrastructure of Mucous Blanket in Otitis Media with Effusion

1988 ◽  
Vol 97 (3) ◽  
pp. 313-317 ◽  
Author(s):  
Masashi Inagaki ◽  
Yasuo Sakakura ◽  
Yuichi Majima ◽  
Takeshi Shimizu ◽  
Kotaro Ukai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Otitis Media ◽  
Middle Ear ◽  
Otitis Media With Effusion ◽  
Ciliated Cells ◽  
Ciliary Movement ◽  
Mucous Layer ◽  
Transmission Electron ◽  
Electron Lucent

We used transmission electron microscopy to study the mucous blanket of the promontory from children with otitis media with effusion. The vast majority of the epithelial cells were secretory, and the rest were ciliated. The mucous blanket consisted of the electron-lucent periciliary fluid and the mucous layer. In the mucous layer, two layers were identified: An inner layer with migrating cells, and an outer layer with specks. Moreover, there was a lucent zone over the nonciliated surface that was as high as the microvilli. The thickness of the periciliary layer was predominantly as great as that of the ciliary tips, which just make contact with the mucous layer; however, the mucous layer occasionally penetrated into the periciliary space. These findings indicated that there is a mucociliary dysfunction in the middle ear caused by a decrease in the number of ciliated cells, and an abnormal interaction between cilia and mucus that would interfere with ciliary movement. Thus, such a system would fail to transport the mucous blanket.

The S2 Layer in the Tracheid Walls of Picea abies Wood: Inhomogeneity in Lignin Distribution and Cell Wall Microstructure

Holzforschung ◽  
2001 ◽  
Vol 55 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Adya P. Singh ◽  
Geoffrey Daniel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Picea Abies ◽  
Lignin Distribution ◽  
Transmission Electron ◽  
S2 Layer ◽  
Tangential Directions ◽  
Electron Lucent

Summary Transmission electron microscopy (TEM) of the walls of Picea abies axial tracheids showed the distribution of lignin in the S2 layer to be inhomogenous. At relatively low magnifications, some parts of the outer and inner S2 layer appeared more electron dense than the mid region in the tracheids which were in contact with or in proximity to a ray. At similar magnifications, the presence of radial and tangential features was observed in the S2 layer of the tracheids which were in contact with or close to rays as well as in those which occurred elsewhere. Higher magnification views showed the S2 layer to be differentiated into electron lucent and dense regions in both radial and tangential directions. A comparison of the counts made of lignin particles in these regions suggested that the differentiation of the S2 wall into lucent and dense regions resulted from inhomogenous distribution of lignin observable at a nano level.

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%.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

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