A bioassay for monitoring cadmium based on bioconvective patterns

Noever, David; Matsos, Helen C.

doi:10.1080/10934529109375633

Cited by 7 publications

(6 citation statements)

References 9 publications

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“…8,9,14 The present work furthers this effort by characterizing the optical diffraction quality of the inhomogeneous Tetrahymena culture. 8,9,14 The present work furthers this effort by characterizing the optical diffraction quality of the inhomogeneous Tetrahymena culture.…”

Section: Introductionmentioning

confidence: 75%

“…8,9 The median inhibitory ͑control͒ concentration was estimated to be between 5 and 7 M Cd ϩ2 . 2͒ and in agreement with previous work.…”

Section: Resultsmentioning

confidence: 99%

“…8,9 For different cadmium levels, comparison of polygonal patterns can be aided by a statistical set characterized by, for example, the size and polygonal shape of two-dimensional patterns. 14 These have been reviewed generally for random patterns and particularly for bioconvective assays.…”

Section: Resultsmentioning

confidence: 99%

“…8 To summarize the recipe, a fresh 100 mL growth medium was innoculated with 1 mL of cells harvested from stock at a stationary growth phase. 8 To summarize the recipe, a fresh 100 mL growth medium was innoculated with 1 mL of cells harvested from stock at a stationary growth phase.…”

Section: Methodsmentioning

confidence: 99%

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Microbial diffraction gratings as optical detectors for heavy metal pollutants

Noever

Matsos

Brittain

et al. 1996

Review of Scientific Instruments

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As a significant industrial pollutant, cadmium is implicated as the cause of itai-itai disease. For biological detection of cadmium toxicity, an assay device has been developed using the motile response of the protozoa species, Tetrahymena pyriformis. This mobile protozoa measures 50 μm in diameter, swims at 10 body lengths per second, and aggregates into macroscopically visible patterns at high organism concentrations. The assay demonstrates a Cd+2 sensitivity better than 1 μM and a toxicity threshold to 5 μM, thus encouraging the study of these microbial cultures as viable pollution detectors. Using two-dimensional diffraction patterns within a Tetrahymena culture, the scattered light intensity varies with different organism densities (population counts). The resulting density profile correlates strongly with the toxic effects at very low dosages for cadmium (<5 ppm) and then for poison protection directly (with nickel and copper antagonists competing with cadmium absorption). In particular, copper dosages as low as 0.1–0.5 mM Cu have shown protective antagonism against cadmium, have enhanced density variability for cultures containing 1 mM Cd+2, and therefore have demonstrated the sensitivity of the optical detection system. In this way, such microbial diffraction patterns give a responsive optical measure of biological culture changes and toxicity determination in aqueous samples of heavy metals and industrial pollutants.

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Section: Introductionmentioning

confidence: 75%

“…8,9 The median inhibitory ͑control͒ concentration was estimated to be between 5 and 7 M Cd ϩ2 . 2͒ and in agreement with previous work.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Microbial diffraction gratings as optical detectors for heavy metal pollutants

Noever

Matsos

Brittain

et al. 1996

Review of Scientific Instruments

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“…These efforts, which lead to the understanding of bioconvective instability, have produced novel and interesting applications. For example, Noever and Matsos [1] proposed a biosensor for monitoring the heavy metal Cadmium based in bioconvective patterns as redundant technique for analysis, a number of researchers [2][3][4][5][6] have been working on the control of bioconvection by applying electrical fields (as in galvanotaxis) to use it as a live micromechanical system to handle small objects immersing in suspensions, Itoh et al [7,8] use some ideas of bioconvection in a study for the motion control of microorganism groups like Euglena gracilis to manipulate objects by using its phototactic orientation (as in phototaxis), and more recently possibly bioconvection seeded the investigation of Kim et al [9,10] for using a feedback control strategy to manipulate the motions of Tetrahymena pyriformis as a microbiorobot, among others. Perhaps, further applications on biomimetics [11][12][13] at the nano-and microscale could be driven by this contribution.…”

Section: Introductionmentioning

confidence: 99%

Bioconvective Linear Stability of Gravitactic Microorganisms

Pérez-Reyes¹,

Dávalos‐Orozco²

2019

Heat and Mass Transfer - Advances in Science and Technology Applications

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Interesting results on the linear bioconvective instability of a suspension of gravitactic microorganisms have been calculated. The hydrodynamic stability is characterized by dimensionless parameters such as the bioconvection Rayleigh number R, the gyrotaxis number G, the motility of microorganisms d, and the wavenumber k of the perturbation. Analytical and numerical solutions are calculated. The analytical one is an asymptotic solution for small wavenumbers (and for any motility number) which agrees very well with the numerical solutions. Two numerical methods are used for the sake of comparison. They are a shooting method and a Galerkin method. Marginal curves of R against k for fixed values of d and G are presented along with curves corresponding to the variation of the critical values of R c and k c. Moreover, those critical values are compared with the experimental data reported in the literature, where the gyrotactic algae Chlamydomonas nivalis is the suspended microorganism. It is shown that the agreement between the present theoretical results and the experiments is very good.

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