Honeybees (Apis mellifera) undergo iron biomineralization, providing the basis for magnetoreception. We showed earlier the presence of superparamagnetic magnetite in iron granules formed in honeybees, and subscribed to the notion that external magnetic fields may cause expansion or contraction of the superparamagnetic particles in an orientation-specific manner, relaying the signal via cytoskeleton (Hsu and Li 1994). In this study, we established a size-density purification procedure, with which quantitative amount of iron granules was obtained from honey bee trophocytes and characterized; the density of iron granules was determined to be 1.25 g/cm3. While we confirmed the presence of superparamagnetic magnetite in the iron granules, we observed changes in the size of the magnetic granules in the trophycytes upon applying additional magnetic field to the cells. A concomitant release of calcium ion was observed by confocal microscope. This size fluctuation triggered the increase of intracellular Ca+2 , which was inhibited by colchicines and latrunculin B, known to be blockers for microtubule and microfilament syntheses, respectively. The associated cytoskeleton may thus relay the magnetosignal, initiating a neural response. A model for the mechanism of magnetoreception in honeybees is proposed, which may be applicable to most, if not all, magnetotactic organisms.
Articles you may be interested inMeasurement of magnetic penetration depth and superconducting energy gap in very thin epitaxial NbN films Appl. Phys. Lett. 96, 072509 (2010); 10.1063/1.3314308Superconducting properties and normalstate resistivity of singlecrystal NbN films prepared by a reactive rf magnetron sputtering method
Well-aligned and randomly grown multiwall nanotubes (MWNTs) fabricated by the radio-field-induced self-bias hot-filament chemical vapour deposition method demonstrate that the growth mechanisms are either 'tip growth' or 'base growth' depending on the size of the catalyst metal particles involved. The carbon nanotubes (CNTs) can also be successfully grown on iron-like bulk alloys when preceded by hydrogen plasma etching. The high yield of CNT fabricated on oxidized metal alloys is attributed to the high active surface area that ensues from etching. The change in field emission currents of MWNTs with temperature is not sensitive but is detectable within the range 300-20 K. This is interpreted to be due to the high aspect ratio of CNTs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.