scholarly journals In addition to cryptochrome 2, magnetic particles with olfactory co-receptor are important for magnetic orientation in termites

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yongyong Gao ◽  
Ping Wen ◽  
Ring T. Cardé ◽  
Huan Xu ◽  
Qiuying Huang

AbstractThe volatile trail pheromone is an ephemeral chemical cue, whereas the geomagnetic field (GMF) provides a stable positional reference. However, it is unclear whether and how the cryptic termites perceive the GMF for orientation in light or darkness until now. Here, we found that the two termite species, Reticulitermes chinensis and Odontotermes formosanus, use the GMF for orientation. Our silencing cryptochrome 2 (Cry2) impaired magnetic orientation in white light but had no significant impact in complete darkness, suggesting that Cry2 can mediate magnetic orientation in termites only under light. Coincidentally, the presence of magnetic particles enabled the magnetic orientation of termites in darkness. When knock-downing the olfactory co-receptor (Orco) to exclude the effect of trail pheromone, unexpectedly, we found that the Orco participated in termite magnetic orientation under both light and darkness. Our findings revealed a novel magnetoreception model depending on the joint action of radical pair, magnetic particle, and olfactory co-receptor.

2021 ◽  
Vol 7 (5) ◽  
pp. 82
Author(s):  
River Gassen ◽  
Dennis Thompkins ◽  
Austin Routt ◽  
Philippe Jones ◽  
Meghan Smith ◽  
...  

Magnetic particles have been evaluated for their biomedical applications as a drug delivery system to treat asthma and other lung diseases. In this study, ferromagnetic barium hexaferrite (BaFe12O19) and iron oxide (Fe3O4) particles were suspended in water or glycerol, as glycerol can be 1000 times more viscous than water. The particle concentration was 2.50 mg/mL for BaFe12O19 particle clusters and 1.00 mg/mL for Fe3O4 particle clusters. The magnetic particle cluster cross-sectional area ranged from 15 to 1000 μμm2, and the particle cluster diameter ranged from 5 to 45 μμm. The magnetic particle clusters were exposed to oscillating or rotating magnetic fields and imaged with an optical microscope. The oscillation frequency of the applied magnetic fields, which was created by homemade wire spools inserted into an optical microscope, ranged from 10 to 180 Hz. The magnetic field magnitudes varied from 0.25 to 9 mT. The minimum magnetic field required for particle cluster rotation or oscillation in glycerol was experimentally measured at different frequencies. The results are in qualitative agreement with a simplified model for single-domain magnetic particles, with an average deviation from the model of 1.7 ± 1.3. The observed difference may be accounted for by the fact that our simplified model does not include effects on particle cluster motion caused by randomly oriented domains in multi-domain magnetic particle clusters, irregular particle cluster size, or magnetic anisotropy, among other effects.


2020 ◽  
Vol 12 (9) ◽  
pp. 1197-1202
Author(s):  
Sun Young Lim ◽  
Tae Jae Lee ◽  
Seol Yi Shin ◽  
Nam Ho Bae ◽  
Seok Jae Lee ◽  
...  

The bacterial DNA was simply purified by magnetic particles with a portable vibration motor. To effectively extract DNA in the field, the 3D-printed device was employed with low electric power system.


2011 ◽  
Vol 236-238 ◽  
pp. 1931-1934
Author(s):  
Zi Ye Wang ◽  
Kang Wang ◽  
Xue Mei Ma

Microchips appear to offer important opportunities for modern research. Microchips based on gold magnetic nanoparticles make manipulation of biomolecules more conveniently, and has the advantage of deducing reaction time. In this study, we first achieved microchips design and fabrication through CO2 laser ablation for immunoassay, and then conjugated mouse IgG to gold magnetic nanoparticles serve as a target. Finally, HRP labeled goat anti mouse IgG binding assay and substrate reaction were performed with disposable microchips and other devices. The results indicated that the reactions carried on successfully and magnetic particles moved well in chips.


2000 ◽  
Vol 15 (10) ◽  
pp. 2114-2120 ◽  
Author(s):  
Toshinobu Yogo ◽  
Tomoyuki Nakamura ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano

A transparent magnetic particle/organic film was synthesized from an iron–organic compound. Iron(III) 3-allylacetylacetonate (IAA) was polymerized followed by in situ hydrolysis yielding an iron oxide particle/oligomer hybrid. The sizes of magnetic particles were dependent upon the hydrolysis conditions of the IAA oligomers. A nanometer-sized ferrimagnetic iron oxide particle/oligomer hybrid showed a magnetization curve with no coercive force at 300 K and that with Hc of 200 Oe at 4.2 K, respectively. The magnetization versus H/T curves at 300 and 77 K were superimposed on each other and satisfied the Langevin equation. The transparent hybrid film showed a magnetization curve at room temperature. The absorption spectrum of the film was shifted to higher energy by 0.14 eV compared with that of bulk magnetite. The absorption edge of the film was blue-shifted.


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4596
Author(s):  
Daniel Kappe ◽  
Laila Bondzio ◽  
Joris Swager ◽  
Andreas Becker ◽  
Björn Büker ◽  
...  

In this review article, we conceptually investigated the requirements of magnetic nanoparticles for their application in biosensing and related them to example systems of our thin-film portfolio. Analyzing intrinsic magnetic properties of different magnetic phases, the size range of the magnetic particles was determined, which is of potential interest for biosensor technology. Different e-beam lithography strategies are utilized to identify possible ways to realize small magnetic particles targeting this size range. Three different particle systems from 500 μm to 50 nm are produced for this purpose, aiming at tunable, vertically magnetized synthetic antiferromagnets, martensitic transformation in a single elliptical, disc-shaped Heusler Ni50Mn32.5Ga17.5 particle and nanocylinders of Co2MnSi-Heusler compound. Perspectively, new applications for these particle systems in combination with microfluidics are addressed. Using the concept of a magnetic on–off ratchet, the most suitable particle system of these three materials is validated with respect to magnetically-driven transport in a microfluidic channel. In addition, options are also discussed for improving the magnetic ratchet for larger particles.


2020 ◽  
Vol 10 (11) ◽  
pp. 3976
Author(s):  
Changje Lee ◽  
Yong-Seok Choi

In this study, we experimentally investigated magnetic particle movement in two-phase flow under an external magnetic field. According to Faraday’s law, the alignment of a magnet is important for power generation. For high generation, it is important to understand how magnetic particles move in two-phase flow. The rotationality could be determined by observing a single particle; however, this is impossible due to the flow conditions. In this study, we estimated nonrotationality based on the vorticity. To eliminate scattered light and improve the signal-to-noise ratio, the laser-induced fluorescence particle image velocimetry technique was used. The solenoid nozzle has a hydraulic diameter of 3 mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 1.2 μm. The excitation and emission wavelengths are 532 and 612 nm, respectively. A thin laser sheet setup was configured. The laser sheet was illuminated on both sides to prevent shadows. The images were captured at 200 μm away from the wall and center of the nozzle. To estimate the decrease in vorticity, the theoretical and single-phase non-magnetic and magnetic particles are compared. The vorticity of magnetic particles is reduced by the external magnetic field.


2002 ◽  
Vol 74 (9) ◽  
pp. 1773-1783 ◽  
Author(s):  
Itamar Willner ◽  
Bilha Willner

Tailored sensoric, electronic, photoelectrochemical, and bioelectrocatalytic functions can be designed by organized molecular or biomolecular nanoparticle hybrid configurations on surfaces. Layered receptor-cross-linked Au nanoparticle assemblies on electrodes act as specific sensors of tunable sensitivities. Layered DNA-cross-linked CdS nanoparticles on electrode supports reveal organized assemblies of controlled electronic and photoelectrochemical properties. Au nanoparticle-FAD semisynthetic cofactor units are reconstituted into apo-glucose oxidase (GOx) and assembled onto electrodes. The resulting enzymes reveal effective electrical contacting with the electrodes, and exhibit bioelectrocatalytic functions toward the oxidation of glucose to gluconic acid. Magneto-switchable electrocatalysis and bioelectrocatalysis are accomplished by the surface modification of magnetic particles with redox-relay units. By the attraction of the modified magnetic particles to the electrode support, or their retraction from the electrode, by means of an external magnet, the electrochemical functions of the magnetic particle-tethered relays can be switched between "ON" and "OFF" states, respectively. The magneto-switchable redox functionalities of the modified particles activate electrocatalytic transformations, such as a biocatalytic chemoluminescence cascade that leads to magneto-switchable light emission or the activation of bioelectrocatalytic processes.


Author(s):  
Suk-Heung Song ◽  
Jinsik Yoon ◽  
Yongkyo Jeong ◽  
Yong-Gyun Jung ◽  
Leon Abelmann ◽  
...  

1988 ◽  
Vol 34 (10) ◽  
pp. 2087-2090 ◽  
Author(s):  
D J Berry ◽  
P M Clark ◽  
C P Price

Abstract We evaluated an immunochemiluminometric assay for human thyrotropin. A chemiluminescent acridinium ester is used as a label, with magnetic-particle separation. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.07 milli-int. unit/L, with a working range of 0.5 to greater than 60.0 milli-int. units/L. Assay accuracy was good as judged from analytical recovery, analysis of external quality-assessment samples, and comparison with an enzyme-amplified immunoassay. There were no significant interferences or cross-reactivities. Twenty-four samples assayed showed aggregation of the magnetic particles. On re-assay, four of these samples showed a significant increase in the measured TSH by the luminescence assay. Assay time for 60 tubes was approximately 3.5 h with the use of a semi-automated luminometer. The reference interval, determined from data on 144 healthy euthyroid subjects, was 0.3-4.0 milli-int. units/L. Sixteen of 19 thyrotoxic patients showed clearly suppressed concentrations of thyrotropin in serum.


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