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Estimation for diameter of superparamagnetic particles in Daphnia resting eggs

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.


ESR spectra on Chlorella measured at 300 K.
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f6-6_53: ESR spectra on Chlorella measured at 300 K.

Mentions: Figure 6 shows ESR spectra of dried Chlorella at 300 K, being quite different from the ESR spectra of Daphnia resting eggs. It is composed of a sharp single line and a set of six lines around g = 2. They are attributed to free radicals resulting from biological processes like the signal B in Figure 1, and to Mn2+ like those observed in the samples of plants leaves20,21. As the result of analysis by an inductively coupled plasma — mass spectrometry (ICP-MS), Chlorella, with that Daphnia were raised, contained Fe as 170 ±10 mg/kg. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.


Estimation for diameter of superparamagnetic particles in Daphnia resting eggs
ESR spectra on Chlorella measured at 300 K.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5036663&req=5

f6-6_53: ESR spectra on Chlorella measured at 300 K.
Mentions: Figure 6 shows ESR spectra of dried Chlorella at 300 K, being quite different from the ESR spectra of Daphnia resting eggs. It is composed of a sharp single line and a set of six lines around g = 2. They are attributed to free radicals resulting from biological processes like the signal B in Figure 1, and to Mn2+ like those observed in the samples of plants leaves20,21. As the result of analysis by an inductively coupled plasma — mass spectrometry (ICP-MS), Chlorella, with that Daphnia were raised, contained Fe as 170 ±10 mg/kg. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.