Ferritin Crystals in the Gut Caeca of a Deep-Sea Hydrothermal Vent Stegocephalid (Crustacea: Amphipoda)

1997 ◽  
Vol 77 (1) ◽  
pp. 269-272 ◽  
Author(s):  
P.G. Moore ◽  
P.S. Rainbow
Keyword(s):  
Trace Metals ◽  
Hydrothermal Vent ◽  
Tectonic Activity ◽  
Amphipod Species ◽  
Single Pair ◽  
Thin Sections ◽  
Widespread Occurrence ◽  
X Ray ◽  
Mid Atlantic Ridge ◽  
High Concentrations

Ferritin crystals and calcium granules are reported from the ventral ceaca of Steleuthera ecoprophycea (Amphipoda: Stegocephalidae) collected from the Snake Pit hydrothermal vent, Mid-Atlantic Ridge (3520 m).In a series of earlier papers (Moore & Rainbow, 1984, 1989, 1992; Moore et al., 1994), the authors described the widespread occurrence of intracellular, octahedral crystals of ferritin in the ventral caeca of a range of stegocephalid amphipod species from the continental shelf epibenthos and oceanic plankton. The discovery at 3500 m of a new Steleuthera species (S. ecoprophycea), from a hydrothermal vent on the Mid-Atlantic Ridge was announced recently by Bellan-Santini & Thurston (1996), and a complete description is provided therein.Oceanic ridge sites are notable for their tectonic activity and the presence of a diversity of trace metals at high concentrations is to be expected in hydrothermal plumes emanating from such regions (German & Angel, 1995). The detoxification of accumulated trace metals in the ventral ceaca of stegocephalid amphipods from uncontaminated environments is now relatively well known (see above), so it was of interest to investigate whether a vent stegocephalid showed an atypical presence of trace metals in detoxified form in cells of the ventral caeca. The results following from an opportunity to investigate this are reported herein.Material was derived from a dive made by the submersible ‘Alvin’ at Snake Pit hydrothermal field, Mid-Atlantic Ridge (23°23′N 44°56′W), 3520 m, on 16 June 1993 (see Bellan-Santini & Thurston, 1996). Steleuthera ecoprophycea was preserved in 70% alcohol. Subsequently to dissection, the single pair of ventral caeca from each of the four damaged amphipods investigated were post-fixed in 4% glutaraldehyde. For electron microscopy and x-ray microanalysis in STEM mode, ventral caecal tissues were then dehydrated through 95% and absolute ethanol, cleared in propylene oxide, embedded in TAAB resin, sectioned at 0·5 μm (semi-thin sections) on a Reichert OmU2 ultramicrotome and examined without staining in a JEOL 100C electron microscope equipped with LINK system EDX energy dispersive x-ray microanalyser.

High Spatial Resolution Microanalysis of Catalyst Particles

1985 ◽  
Vol 62 ◽  
Author(s):  
C. E. Lyman
Keyword(s):  
Image Feature ◽  
Single Element ◽  
X Rays ◽  
Qualitative And Quantitative Analysis ◽  
Thin Sections ◽  
X Ray ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
High Concentrations ◽  
Electron Energy Loss

ABSTRACTQualitative and quantitative analysis of small catalyst particles is possible in the analytical electron microscope down to analysis areas on the order of 10 nm in diameter. The location of elements in the image field can be determined either by placing the electron probe on a particu-lar image feature or by forming a digital x-ray image showing the distribu-tion of various elements. In either case analysis of specimens of well defined thickness such as microtomed thin sections preserves spatial relationships in catalyst particles and simplifies interpretation of single element x-ray images. Electron energy loss spectroscopy can be combined with x-ray spectroscopy to reduce the ambiguity in x-ray spectra caused by spurious x-rays generated by electrons scattered from the analy-sis area to regions of high concentrations of elements removed from the analysis area.

scholarly journals Supplementary material to "Successional patterns of (trace) metals and microorganisms in the Rainbow hydrothermal vent plume at the Mid-Atlantic Ridge"

2019 ◽  
Author(s):  
Sabine Haalboom ◽  
David M. Price ◽  
Furu Mienis ◽  
Judith D. L. van Bleijswijk ◽  
Henko C. de Stigter ◽  
...  
Keyword(s):  
Trace Metals ◽  
Hydrothermal Vent ◽  
Mid Atlantic Ridge ◽  
Supplementary Material

Quantitative EELS mapping of biological thin sections

1992 ◽  
Vol 50 (2) ◽  
pp. 1568-1569
Author(s):  
Y.Y. Wang ◽  
Z. Shao ◽  
R. Ho ◽  
A.V. Somlyo ◽  
A.P. Somlyo
Keyword(s):  
Spatial Resolution ◽  
Power Law ◽  
High Spatial Resolution ◽  
Local Composition ◽  
Thin Sections ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
High Concentrations ◽  
Electron Energy Loss

X-ray microanalysis and electron energy loss spectroscopy are reliable methods for determining at high spatial resolution the local composition of biological materials. EELS imaging, although potentially more sensitive than X-ray analysis, is complicated by the large background of EELS spectra. The conventional power law fitting of the EELS background can only be used for analysis of high concentrations and/or very thin sections (t< 0.3 λ) and it is not reliable for mapping low elemental concentrations. For the detection of low elemental concentrations at high spatial resolution, the background subtraction of the EELS spectrum and correction of long term microscope drift are critical, and limit the use of conventional energy filtered transmission electron microscopy. Therefore, we used energy filtered STEM with multiple least squares fitting, including the plural plasmon contribution to the background, to obtain quantitative phosphorus (P) and calcium (Ca) concentration maps of cryosections.The failure of the power law is due to the plural scattering contributions to the Background.

3-D reconstruction of molecular shape from microcrystal thin sections

1983 ◽  
Vol 41 ◽  
pp. 748-749
Author(s):  
S. Cusack ◽  
J.-C. Jésior
Keyword(s):  
Three Dimensional ◽  
Molecular Shape ◽  
Biological Molecules ◽  
Fourier Space ◽  
Single Particles ◽  
Thin Sections ◽  
Standard Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimensional Reconstruction

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).

Chemical modification of the bacterial wall to determine sites of metal deposition

1978 ◽  
Vol 36 (2) ◽  
pp. 350-351
Author(s):  
T. J. Beveridge
Keyword(s):  
Electron Scattering ◽  
Metal Salt ◽  
Metal Deposition ◽  
Suitable Model ◽  
X Ray Diffraction ◽  
Subtilis Cell ◽  
Thin Sections ◽  
X Ray ◽  
Section Data ◽  
Metal Impregnation

The Bacillus subtilis cell wall provides a protective sacculus about the vital constituents of the bacterium and consists of a collection of anionic hetero- and homopolymers which are mainly polysaccharidic. We recently demonstrated that unfixed walls were able to trap and retain substantial amounts of metal when suspended in aqueous metal salt solutions. These walls were briefly mixed with low concentration metal solutions (5mM for 10 min at 22°C), were well washed with deionized distilled water, and the quantity of metal uptake (atomic absorption and X-ray fluorescence), the type of staining response (electron scattering profile of thin-sections), and the crystallinity of the deposition product (X-ray diffraction of embedded specimens) determined.Since most biological material possesses little electron scattering ability electron microscopists have been forced to depend on heavy metal impregnation of the specimen before obtaining thin-section data. Our experience with these walls suggested that they may provide a suitable model system with which to study the sites of reaction for this metal deposition.

XRF and PIXE Analysis of light and Dark Adapted Ocular Tissue

1982 ◽  
Vol 40 ◽  
pp. 190-191
Author(s):  
B. J. Panessa ◽  
H. W. Kraner ◽  
J. B. Warren ◽  
K. W. Jones
Keyword(s):  
Trace Metals ◽  
Pigment Epithelium ◽  
Nerve Impulse ◽  
Light Response ◽  
Ocular Tissue ◽  
Emission Spectrometry ◽  
Retinol Dehydrogenase ◽  
Pixe Analysis ◽  
X Ray ◽  
Optimal Function

During photoexcitation the retina requires specific electrolytes and trace metals for optimal function (Na, Mg, Cl, K, Ca, S, P, Cu and Zn). According to Hagins (1981), photoexcitation and generation of a nerve impulse involves the movement of Ca from the rhodopsin-ladened membranes of the rod outer segment (ROS) to the plasmalemma, which in turn decreases the in-flow of Na into the photoreceptor, resulting in hyperpolarization. In toad isolated retinas, the presence of Ba has been found to increase the amplitude and prolong the delay of the light response (Brown and Flaming, 1978). Trace metals such as Cu, Zn and Se are essential for the activity of the metalloenzymes of the retina and retina pigment epithelium (RPE) (i.e. carbonic anhydrase, retinol dehydrogenase, tyrosinase, glutathione peroxidase, superoxide dismutase...). Therefore the content and fluctuations of these elements in the retina and choroid are of fundamental importance for the maintenance of vision. This paper presents elemental data from light and dark adapted frog ocular tissues examined by electron beam induced x-ray microanalysis, x-ray fluorescence spectrometry (XRF) and proton induced x-ray emission spectrometry (PIXE).

Quantification and localization of trace metals in natural plankton cells using a synchrotron X-ray fluorescence microprobe

2003 ◽  
Vol 104 ◽  
pp. 435-438 ◽  
Author(s):  
B. S. Twining ◽  
S. B. Baines ◽  
N. S. Fisher ◽  
C. Jacobsen ◽  
J. Maser
Keyword(s):  
Trace Metals ◽  
X Ray

scholarly journals A small molecule compound with an indole moiety inhibits the main protease of SARS-CoV-2 and blocks virus replication

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shin-ichiro Hattori ◽  
Nobuyo Higashi-Kuwata ◽  
Hironori Hayashi ◽  
Srinivasa Rao Allu ◽  
Jakka Raghavaiah ◽  
...  
Keyword(s):  
Small Molecule ◽  
Covalent Bond ◽  
Amino Acid Residues ◽  
X Ray ◽  
Viral Breakthrough ◽  
Main Protease ◽  
Small Molecule Compound ◽  
Polar Interactions ◽  
High Concentrations

AbstractExcept remdesivir, no specific antivirals for SARS-CoV-2 infection are currently available. Here, we characterize two small-molecule-compounds, named GRL-1720 and 5h, containing an indoline and indole moiety, respectively, which target the SARS-CoV-2 main protease (Mpro). We use VeroE6 cell-based assays with RNA-qPCR, cytopathic assays, and immunocytochemistry and show both compounds to block the infectivity of SARS-CoV-2 with EC50 values of 15 ± 4 and 4.2 ± 0.7 μM for GRL-1720 and 5h, respectively. Remdesivir permitted viral breakthrough at high concentrations; however, compound 5h completely blocks SARS-CoV-2 infection in vitro without viral breakthrough or detectable cytotoxicity. Combination of 5h and remdesivir exhibits synergism against SARS-CoV-2. Additional X-ray structural analysis show that 5h forms a covalent bond with Mpro and makes polar interactions with multiple active site amino acid residues. The present data suggest that 5h might serve as a lead Mpro inhibitor for the development of therapeutics for SARS-CoV-2 infection.

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