Detection of chrysotile asbestos by using a chrysotile-binding protein

Our plain-English summary of Detection of chrysotile asbestos by using a chrysotile-binding protein, by A. Kuroda, T. Nishimura, T. Ishida, et al (Biotechnology and Bioengineering, 2008).

The study

• Authors: A. Kuroda, T. Nishimura, T. Ishida, R. Hirota, K. Nomura
• Journal: Biotechnology and Bioengineering
• Published: 2008;99(2):285-9
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In the current studies, we found that the DksA protein from Escherichia coli binds strongly to chrysotile, which is the most commonly used form of asbestos. We developed a convenient colorimetric assay for chrysotile using a fusion of DksA and alkaline phosphatase along with 5-bromo-4-chloro-3-indolyl-phosphate and nitro blue tetrazolium as substrates. Also, using a fusion of DksA and green-fluorescent protein, we were able to detect chrysotile by fluorescence microscopy.

(c) 2007 Wiley Periodicals, Inc.

In plain English

This Hiroshima University laboratory study developed a protein-based test for chrysotile asbestos; it did not study people or disease. The authors searched proteins from the bacterium Escherichia coli for ones that bind chrysotile. They found several and joined one, DksA, to an enzyme that produces a blue color (DksA-AP). On filter membranes, the color grew with the amount of chrysotile. The scanned text gives a detection limit of 0.01 mg; the unit is uncertain because the scan seems to render 'micro' signs as 'm' elsewhere. In rockwool mixed with chrysotile, the bound protein was released from the washed sample and then reacted: a one-minute color reaction detected 1% chrysotile, and a 30-minute incubation detected 0.1%. The test distinguished chrysotile from amosite, crocidolite and glass wool in rockwool, but the authors said quantitative analysis was still needed to establish its specificity for different asbestos types. A version joined to a green fluorescent protein made chrysotile visible under a fluorescence microscope. The authors concluded the method could likely be adapted for on-site testing. They noted that further investigation was necessary and that chrysotile levels do not always represent total asbestos levels.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory method-development study: identifying a bacterial protein that binds chrysotile and using it in color-based and fluorescence detection tests. There were no human subjects.
• Who was studied: No people were studied. The materials were chrysotile samples from the Japan Association for Working Environment Measurement, rockwool, glass wool, and proteins from Escherichia coli (Hiroshima University, Japan).
• Exposure: Chrysotile asbestos as the target of detection. Amosite, crocidolite and glass wool were tested to check whether the assay told them apart from chrysotile in rockwool.
• Main results:
  • Several E. coli proteins appeared to bind chrysotile, including DksA.
  • The DksA-alkaline phosphatase fusion (DksA-AP) bound chrysotile even at 300 mM salt.
  • On filter membranes, the blue color reflected the amount of chrysotile. The scanned text gives the detection limit as 0.01 mg. The unit cannot be confirmed from this text, because the scan appears to render the 'micro' sign as 'm' elsewhere.
  • In rockwool, after the bound DksA-AP was released (eluted) from the washed sample, a one-minute color reaction detected 1% chrysotile.
  • In rockwool, a 30-minute color-development incubation with the eluted DksA-AP detected as little as 0.1% chrysotile.
  • In rockwool, the assay distinguished chrysotile from amosite, crocidolite and glass wool. The authors added that quantitative analysis is needed to establish specificity across asbestos types.
  • Alkaline phosphatase without DksA never produced blue color in the assay within 60 minutes.
  • Under fluorescence microscopy, DksA-GFP bound chrysotile but GFP alone did not, under the conditions used.
  • A preliminary test on wall and ceiling building materials gave chrysotile contents comparable to the conventional X-ray method. These data were not shown.
• The authors' conclusion: The authors concluded that DksA-AP can detect as little as 0.1% chrysotile in rockwool. They stated that the method should be adaptable to on-site or high-throughput asbestos analysis.
• Limitations the authors state:
  • Quantitative analysis is still needed to establish how specific DksA-AP is for different types of asbestos.
  • The color test was complicated when the building materials tested were themselves colored.
  • The method detects chrysotile only, and chrysotile concentration does not always represent total asbestos levels.
  • The authors stated that further investigation is necessary.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Selective detection of airborne asbestos fibers using protein-based fluorescent probes — T. Ishida, M. Alexandrov, et al. (2010)
• Molecular engineering of a fluorescent bioprobe for sensitive and selective detection of amphibole asbestos — T. Ishida, M. Alexandrov, et al. (2013)
• Evaluation of sensitivity of fluorescence-based asbestos detection by correlative microscopy — T. Ishida, M. Alexandrov, et al. (2012)
• Calretinin Functions in Malignant Mesothelioma Cells Cannot Be Replaced by the Closely Related Ca2+-Binding Proteins Calbindin-D28k and Parvalbumin — J. Wörthmüller, A. Oberson, et al. (2018)
• Differential Counting of Asbestos Using Phase Contrast and Fluorescence Microscopy — T. Nishimura, M. Alexandrov, et al. (2016)
• Rapid on-site detection of airborne asbestos fibers and potentially hazardous nanomaterials using fluorescence microscopy-based biosensing — A. Kuroda, M. Alexandrov, et al. (2016)

Browse return to medical research.