User:Jonathan Cline/Notebook/Melaminometer

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Melaminometer: Easily Detect Harmful Melamine and Related Analogues.

Monday, October 27, 2008 - China discovers eggs tainted with melamine. By DAVID BARBOZA, The New York Times. SHANGHAI, China - Hong Kong food inspectors have found eggs imported from northeast China to be contaminated with high levels of melamine, the toxic industrial additive at the heart of an adulteration scandal over Chinese milk products. The findings have raised new concerns here that a far wider array of China-produced foods than previously believed could be contaminated by melamine, which already has sickened more than 50,000 children in China and led to at least four deaths. Melamine C3H6N6

For biologists: Read the "Much needed product for world health" proposal first, then skip to the "Specific Metabolic Activity".

For DIY-biologists or iGEM types: Read the "As proof of DIY Bio" proposal first, then skip to "Biochemistry Background".

For non-scientists and/or normal people: Read the "Much needed product for world health" proposal first, then skip to "Toxicology Background" and other background information.

Project Proposal

Product Need

  • Commercial food testing is unlikely to change in the short term
  • Commercial testing has failed to meet safety standards demanded by consumers
  • A method for establishing harmful content in food is needed at "Point-of-care"
    • Harmful product may especially exist in resource-constrained communities where commercial testing is lax
    • Consumers should have a means of testing food themselves.




Historical Perspective

November 2008: U.S. FDA halts all dairy imports from China, plus cheese, cereals, bakery products, ready-to-eat packaged breakfast foods, soft drinks, soft candy, cat and dog food.


October 2008: Harmful levels of Melamine contamination found in eggs exported from China to Hong Kong, in bread in Taiwan, and in crackers in Philippines. Popular media reports over 50,000 people adversely affected.

2008: Large-scale contamination found in wide variety of milk products exported from China. Hospitalized and/or affected population reported in popular media to be between 10,000 and 50,000 people. U.S. FDA issues guidelines for maximum content.

2007: Pet food contamination triggers intensive research into chemically or physically determining presence of harmful agents & their metabolic pathways.

Mid 2000s: Metabolism of melamine and/or related compounds in bacteria metabolism studied in further detail using genetic analysis.

Mid 1990s: biotech interest in melamine metabolism due to possibility of enhancing plant nitrogen takeup in optimizing fertilization. Not much known about metabolic pathway. Nothing known about related gene expression. Bacterial strains known; Pseudomonas isolates, two Klebsiella isolates, and a Rhodococcus isolate).

Early 1990s: Melamine catabolism studied as means to degrade atrazine herbicide in the U.S. Pseudomonas used and first plasmids created.

Mid 1980s: HPLC analysis allows quantitative measurement of melamine pathway; prior to this, identification of intermediates is difficult.

Late 1970s: Partial, tentative, data into melamine degradation is published.

Dry Lab Design Method

  1. Project definition
    1. Iteratively (re-)define project
    2. Verify theoretical feasibility
    3. Repeat from above
  2. Project Feasibility
    1. Research existing metabolism/catabolism/enzymatic activity
    2. Research existing microbe structure
    3. Verify theoretical feasibility of inserting metabolic path into desired microbe
      1. Need a suitable vector -- not all plasmids are appropriate for all gut bacteria
      2. Must be stable, i.e., reproduce from generation to generation
    4. Verify theoretical compatibility of biological components
      1. Find possible promoters, repressors = regulators for gene expression
      2. Design decision: in vivo microbial system, or in vitro cell free system?
    5. Repeat from above
  3. Project Testability
    1. Research method for testing microbe
    2. Research required controls, blanks, positives, samples
    3. Repeat from above for design of test method, as necessary
  4. Project Modeling
    1. Model theoretical operation of microbe
      1. Pathways + membrane + multi-cell
      2. Gene regulation
    2. Model theoretical compatibility of components
    3. Model testing method
    4. Obtain expert assistance/advice on design & models
    5. Repeat from above
  5. Project Implementation Scoping
    1. Scope building organism (cost, labor, designer)
    2. Funding source
    3. Materials source
    4. Proceed to wet lab phase

Wet Lab Implementation Method

  1. Verify Prior Research
    1. Obtain close analogues to original microbes & plasmids
      1. Culture control & target
    2. Modify strain
    3. Verify strain
      1. Compare growth & products
      2. Measure against control
      3. Compare to model
      4. Improve model
    4. Repeat as necessary for validation of original & current protocols
  2. Optimize for Desired Function
    1. TBD
    2. Isolate to enzymes
    3. Switch strains or microbes