Use of Swimming Cells of Green Paramecia for Detection of Toxic Rare Earth Ions at Lethal and Sub-lethal Concentration (original) (raw)
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Members of Paramecium species are often referred to as “swimming neurons or sensory cells” applicable to micro-biorobotics or BioMEMS (biological micro-electro-mechanical systems). Paramecium bursaria known as green paramecia is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the living cells of green paramecia as micro-machines controllable under electrical, optical and magnetic signals, has a variety of engineering applications such as transportation of micro-sized particles (ingested within the cells) in the capillary systems. In the present study, we aimed to test if the swimming environment of green paramecia can be implementable on microchips. For thi purpose, the series of microchips were prepared for cellular swimming platform for green paramecia through fabrication of poly(methyl methacrylate) master plates using the programmable micro-milling system followed by polydimethylsiloxane-based micro-casting. Finally, microchips equipped with optimally sized micro-flow channels for allowing the single cell traffic by swimming green paramecia were successfully prepared, and thus further studies for application of green paramecium cells in BioMEMS are encouraged.
2012
Some researchers have described the cells of Paramecium species as " swimming sensory cells " or " swimming neurons " applicable to micro-biorobotics and biological micro-electromechanical systems (BioMEMS). Paramecium species including green paramecia (Paramecium bursaria) migrate towards the anodic electrode when exposed to an electric field. This type of cellular movement is known as galvanotaxis. Because the ideal micromachines designed for microparticle transport must have a capacity for loading certain numbers of particles, P. bursaria was chosen as a model organism. In this study, we show enhanced microparticle transport by overcoming (i) the particle size limitation for the cell-mediated transport of microspheres of up to ca. 10 µm size (doubling the size of particles ever reported) and (ii) the limit of cellular migration distance manifested by galvanotactically stimulated cells.
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Bacterial biomasses are suitable and inexpensive biosorbents for the removal of metal ions. The Gram-negative betaproteobacterium Cupriavidus necator H16 is found in soil and freshwater environments. In this study, C. necator H16 was used to remove chromium (Cr), arsenic (As), aluminum (Al), and cadmium (Cd) ions from water. Minimum inhibition concentration (MIC) values of C. necator to Cr, As, Al, and Cd were found as 76, 69, 341, and 275 mg/L, respectively. The highest rates of Cr, As, Al, and Cd bioremoval were 45, 60, 54, and 78%, respectively. pH levels between 6.0 and 8.0 and an average temperature of 30 °C were optimum for the most efficient bioremoval. Scanning electron microscopy (SEM) images of Cd-treated cells showed that the morphology of the cells was significantly impaired compared to the control. Shifts in the Fourier transform infrared spectroscopy analysis (FTIR) spectra of the Cd-treated cell walls also confirmed the presence of active groups. As a result, it can b...
— A novel method for biological monitoring to detect toxic substances in water was developed by using the proto-zoan Raphidiophrys contractilis as an indicator organism. In this system (named HELIOSENSOR), the adhesion of R. contractilis to the substratum was used as a measure of the health of the living organisms. A flow-through type chamber was designed for toxicity testing, in which cells that had been damaged by harmful materials were flushed away by the water flow. The number of protozoa was continuously monitored with a digital camera. The test results revealed that this monitoring system has high durability and efficiency compared with other bio-monitoring systems, enabling us to make a quicker and easier detection of toxic substances. This system showed particularly high sensitivity to heavy metals such as mercury, arsenic, lead and cadmium. Due to high sensitivity (ex. ~ 10-7 M for Hg 2+), fast response time (<20 min) and small size (30×14×20 cm), this system has distinct advantages over other conventional biomonitoring systems using multicellular animals such as fish and crustaceans.