Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: magnetosomes

Sortuj według:

Ogranicz wyniki do:

Microbial synthesis of unique nanoscale minerals - challenges and prospects

Maliszewska Irena, Kocek Daria, Wanarska Ewelina

Physicochemical Problems of Mineral Processing

2020

Vol. 56, iss. 6

244--256

In this review, we highlight new insights and place the molecular mechanisms of the biogenesis of nanomaterials such as silicified frustules, coccoliths, magnetosomes and bacterial nanowires in the context of the complex biology of a microbial cell. The silicified frustules are formed by diatoms, which are a widespread group of organisms found in the oceans, fresh water, soil and wet surfaces. They are especially important in the oceans, where it is estimated that they contribute to 45% of total primary ocean production. Coccolith is a collective term that designates all of the biomineralized, calcified scales produced by extant and extinct haptophytes (single-celled algae). The orientation of magnetotactic bacteria is based on the presence of unique organelles, magnetosomes, which are intracellular, membrane-enclosed, nanometre-sized crystals of magnetic iron minerals. The discovery of bacterial conductive structures, called nanowires, has fascinated scientists for almost a decade. Nanowires enable bacteria to transfer electrons over micrometer distances to extracellular electron acceptors such as insoluble metal oxides or electrodes. The possible applications of these extremely interesting nanomaterials in different areas of life is also considered.

The Effect of Sonication on Acoustic Properties of Biogenic Ferroparticle Suspension

Józefczak A., Hornowski T., Król A., Molčan M., Leszczyński B., Timko M.

Archives of Acoustics

2016

Vol. 41, No. 1

161--168

Superparamagnetic iron oxide nanoparticles (SPION) synthesised chemically usually need the modification of the particle surface. Other natural sources of magnetic particles are various magnetotactic bacteria. Magnetosomes isolated from magnetotactic bacteria are organelles consisting of magnetite (Fe3O4) or greigite (Fe3S4) crystals enclosed by a biological membrane. Magnetotactic bacteria produce their magnetic particles in chains. The process of isolation of magnetosome chains from the body of bacteria consists of a series of cycles of centrifugation and magnetic decantation. Using a high-energy ultrasound it is possible to break the magnetosome chains into individual nanoparticles – magnetosomes. This study presents the effect of sonication of magnetosome suspension on their acoustic properties, that is speed and attenuation of the sound. Acoustic propagation parameters are measured using ultrasonic spectroscopy based on FFT spectral analysis of the received pulses. The speed and attenuation of ultrasonic waves in magnetosome suspensions are analysed as a function of frequency, temperature, magnetic field intensity, and the angle between the direction of the wave and the direction of the field.

Rozkład wielkości magnetosomu w bakterii magnetotaktycznej

Jandacka P., Vojtkova H., Alexa P., Kolicova P., Simkova L.

Inżynieria Mineralna

2012

R. 13, nr 1

55-58

Praca analizuje rozkład statystyczny magnetosomów w bakterii magnetotaktycznej. Zawiera również teoretyczne uzasadnienie dotyczące procesu biomineralizacji, który prowadzi do produkcji jednodomenowych nanocząstek wewnątrz bakterii.

The paper analyzes a statistic distribution of magnetosomes in magnetotactic bacteria. It also contains theoretical reasoning on the nature of a biomineralization process which aims to produce single-domain nanoparticles inside bacteria.