Asymmetric distribution of metals in the Xenopus laevis oocyte: a synchrotron X-ray fluorescence microprobe study

2007 ◽  
Vol 85 (5) ◽  
pp. 537-542 ◽  
Author(s):  
Bogdan Florin Gh. Popescu ◽  
Zachery R. Belak ◽  
Konstantin Ignatyev ◽  
Nick Ovsenek ◽  
Helen Nichol

The asymmetric distribution of many components of the Xenopus oocyte, including RNA, proteins, and pigment, provides a framework for cellular specialization during development. During maturation, Xenopus oocytes also acquire metals needed for development, but apart from zinc, little is known about their distribution. Synchrotron X-ray fluorescence microprobe was used to map iron, copper, and zinc and the metalloid selenium in a whole oocyte. Iron, zinc, and copper were asymmetrically distributed in the cytoplasm, while selenium and copper were more abundant in the nucleus. A zone of high copper and zinc was seen in the animal pole cytoplasm. Iron was also concentrated in the animal pole but did not colocalize with zinc, copper, or pigment accumulations. This asymmetry of metal deposition may be important for normal development. Synchrotron X-ray fluorescence microprobe will be a useful tool to examine how metals accumulate and redistribute during fertilization and embryonic development.

2005 ◽  
Vol 18 (7) ◽  
pp. 655-663 ◽  
Author(s):  
Loïc Perring ◽  
Daniel Andrey ◽  
Marija Basic-Dvorzak ◽  
Daniel Hammer

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1173
Author(s):  
Fotini Martsouka ◽  
Konstantinos Papagiannopoulos ◽  
Sophia Hatziantoniou ◽  
Martin Barlog ◽  
Giorgos Lagiopoulos ◽  
...  

Six pharmaceutical pastes were prepared using chemically modified kaolin and talc powders. Tests were conducted to determine their structural and chemical characteristics as well as their antimicrobial protection, thus rendering them suitable for cosmetic and pharmaceutical uses. Kaolin and talc were treated chemically via the cation exchange method to load the clay particles with copper and zinc ions, two cations well known for their antimicrobial properties. Mineralogical analyses were conducted by using X-ray diffraction (XRD) before and after the modification, confirming the mineralogical purity of the samples. Scanning electron microscopy was also used in conjunction with energy dispersed spectroscopy (SEM-EDS) to obtain chemical mapping images, revealing the dispersion of the added metals upon the clay minerals surfaces. Moreover, chemical analysis has been performed (XRF) to validate the enrichment of the clays with each metal utilizing the cation exchange capacity. All modified samples showed the expected elevated concentration in copper or zinc in comparison to their unmodified versions. From the X-ray photoelectron spectroscopy (XPS), the chemical state of the samples’ surfaces was investigated, revealing the presence of salt compounds and indicating the oxidation state of adsorbed metals. Finally, the resistance of pastes in microbial growth when challenged with bacteria, molds, and yeasts was assessed. The evaluation is based on the European Pharmacopeia (EP) criteria.


2021 ◽  
pp. 1098612X2110262
Author(s):  
Stacie Summers ◽  
Jonathan Stockman ◽  
Jennifer A Larsen

Objectives The aim of this study was to analyze iron, copper and zinc concentrations in commercial foods and compare among food formats (dry, canned, raw), foods marketed by age category (adult 1+ years and senior 7+ years) and foods intended for adult maintenance vs all life stages. Methods In total, 112 commercial non-therapeutic food products marketed for healthy adult and senior cats were purchased in the USA. Foods were analyzed for their proximate composition. Trace mineral concentrations were measured using inductively coupled argon plasma–optical emission spectroscopy and described on a calculated metabolizable energy basis using standard modified Atwater values. Results Measured iron (median 58.4 mg/1000 kcal [range 15.7–379.0]), copper (median 5.6 mg/1000 kcal [range 0.8–13.3]) and zinc (median 47.6 mg/1000 kcal [range 7.6–128.1]) concentrations were highly variable among cat foods. When all food products – regardless of their nutritional adequacy substantiation method – were compared with the Association of American Feed Control Officials regulatory minimums, 13/112 food products had a mineral deficiency, of which a majority (n = 11/13) were raw food products. Raw foods had significantly lower trace mineral concentrations compared with dry food products and, except for copper, canned food products. Cat foods marketed for senior cats had higher iron ( P = 0.019) and zinc ( P <0.0001) concentrations than foods marketed for adult cats. Foods intended for adult maintenance had higher iron ( P = 0.003) and zinc concentrations than foods intended for all life stages ( P <0.0001). Conclusions and relevance Iron, copper and zinc concentrations in commercial non-therapeutic foods for adult and senior cats are highly variable. A minority of foods – mainly raw food products – were deficient in these minerals. It is unknown if some foods with high trace mineral concentrations could have adverse effects as studies are needed to establish safe upper limits for dietary intake of trace minerals in healthy cats.


2010 ◽  
Vol 63 (19) ◽  
pp. 3335-3347 ◽  
Author(s):  
Sanjit Konar ◽  
Kevin Gagnon ◽  
Abraham Clearfield ◽  
Charles Thompson ◽  
Jennifer Hartle ◽  
...  

1991 ◽  
Vol 31 (1) ◽  
pp. 63-70 ◽  
Author(s):  
J. S. Oosting ◽  
A. G. Lemmens ◽  
G. J. Van Den Berg ◽  
A. C. Beynen

2021 ◽  
Author(s):  
Dilek Çanakçı

Abstract In this study, hydroxyapatites reinforced with Boron, Copper and Zinc at different rates were produced using the sol-gel method. Different amounts of metal during the production of hydroxyapatite were used to observe the amount of crystallization and morphological differences in their structures. The characterization of the metal-doped HAp was carried out by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The data indicated that the Ca/P stoichiometric ratios of the samples varied between 1.71 and 2, so their morphologies were different from each other. The absorption behavior of novel metal-doped HAp samples was evaluated at room temperature by UV-vis spectroscopy. In the absorption spectra of the samples, absorption bands formed in similar regions. In addition, the thermal behavior of HAp samples was investigated using TG/DTA techniques. The results of the analysis showed that heat resistance of the new synthesized samples was quite high.


2015 ◽  
Vol 3 (1) ◽  
pp. 10-14
Author(s):  
Tânia Nogueira ◽  
Mariana Semedo ◽  
Elisabete Cunha

Background: Metals such as copper and zinc are crucial in several vital functions in the human body; the absence of these metals can cause serious illness. When in excess, however, they can have toxic effects which may be associated with carcinogenesis, as is described in the literature. Thus, it is important to realize that without these essential metals in their due proportion, the human body could not maintain its proper metabolic function. Methods: The main goal of this paper was to compare qualitatively and semi-quantitatively the amount of both copper and zinc present in the tumor tissue (tissue from patients who had undergone partial or radical nephrectomy) andin the control tissue (which was adjacent to the tumor tissue). This study was carried out using Scanning Electron Microscopy coupled with X-Ray Microanalysis (SEM-XRM). Results: There is a different concentrations of copper and zinc in the samples of tumor tissue and controls that were studied. Conclusion: This work complements previously published results about the presence of metals in the human body and their probable influence on carcinogenesis


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