More on UV & genetic mutation
May I please impose on you to forward a couple of questions to Dr. Kelly Reynolds (re: “On Tap: The Evolution of New Bacterial Pathogens,” WC&P, August 2001, pp. 102)? Please, define the terms used in the paragraph titled “Genetic exchange” (I think they have a meaning relating to microbiological usage outside the common understanding of the words), and will a weak UV sanitization unit wreak havoc interims (sic) or “Genetic exchange”?
I am giving a paper on UV sanitization in October for the Illinois section of the WQA where ambient conditions like voltage, light transmission, shadowing, temperature and solarization are discussed. If genetic exchange is an instantaneous phenomenon, then weakened output could be a problem. Thank you.
P.S.: Her contributions are excellent, however, I need to have dictionary in hand when I read her articles. Don’t change or water her articles down; a little research is good for the reader!
Warren Searles, President
HydroTec Systems Co.
The author replies: Thank you for your support of the On Tap articles in WC&P. You pose some challenging questions regarding the subject on genetic exchange and increased potential of genetic exchange following stress to organisms exposed to a variety of treatment and environmental effects.
The following is a list of definitions that may be useful to you:
- Gene—a unit of hereditary material that forms a discrete part of the chromosome of most organisms, encoding information in the form of a DNA sequence.
- Genetic exchange or recombination—the exchange of genes between two chromosomes following the extraction of DNA, or the production of a copy DNA, from one source and the insertion into another.
- Mutation—the change in the structure of DNA or the number of genes or chromosomes in a cell that results in an abnormal characteristic being expressed. Mutations arise naturally or are brought about by chemical mutagens, or ionizing radiation.
- Transduction—the transfer of bacterial genes from one bacterium to another by a phage (phage are viruses of bacteria that are almost always found in association with the host cells).
- Transformation—a permanent genetic change induced in a cell following incorporation of new DNA (the process used by genetic engineers often for improvement of agricultural products). The DNA may be “free-floating” in the surrounding environment of the bacteria.
- Conjugation—the exchange of genetic information across the cell membrane of two bacterial cells in direct contact with one another.
All of these events of genetic transfer happen consistently in nature. Most do not affect the virulence of the organism. The type of genetic alteration that is perhaps the most common is mutations. These are usually single-point changes on the genetic map of the organism. Advantageous mutations may become dominant due to selection pressures in the environment. As evidenced by the use of disinfection treatments in wastewater/drinking water for nearly a century, it is not likely that such treatments cause a major impact on the evolution of new, more deadly pathogens.
Although it is known that natural UV light can cause mutations in microbial genomes, no information is available on the relationship between dose and response of the bacterial agents with respect to genetic exchange potentials. Some research is currently focused on the potential for genetic exchange on biofilms attached to filter surfaces, but the jury is still out on whether this is a public health concern.
Genetic exchange is a random phenomenon and difficult to predict in light of the many variables that natural environmental organisms are exposed to. Thus, at this point, it is not possible to comment on the impact of weak UV sanitization and it’s relationship to genetic exchange.
Please, continue to read the articles in WC&P for updated information as it becomes available.
Dr. Kelly A. Reynolds, MSPH, Ph.D.
Water For People & WQA
The following is a letter from Water For People’s Amy Douglas to Water For People’s Kelley Thompson that was forwarded to WC&P:
Here’s the information I mentioned for possible inclusion in the WQA Newsfax. I realize this is way too much but wanted to give you a full activities report. We appreciate the support of the WQA and its members and look forward to continuing this relationship in the future. I am copying several people on this message as well since the extent of our partnership extends beyond our two organizations.
Last September, Water For People and the Water Quality Association began forging a new relationship at the suggestion of one of its members, (Kinetico’s) Karen Zack. During the fall leadership conference of WQA, WFP was invited to make two presentations, one to the board of directors and another to the World Assembly Division—the association’s international arm.
Following in the footsteps of that initial interest, WFP was invited to present at the annual conference and receive a complimentary exhibitor’s booth and conference registration for a staff and WFP’s president, Jerry Smith. Since that time, WFP has seen a new level of support emerging from the point-of-use industry, both financially and through educational activities.
In the past six-month period, WFP has seen new support from more than 50 WQA individuals, associations and businesses, totaling more than $15,000 in donations. A big part of this emerging support began at the conference but has also been fostered by C.R. Hall, WQA president, who has demonstrated his own support of WFP through a recent mailing to the 2,000-plus WQA members.
In addition, two of the industry’s primary trade publications, Water Conditioning & Purification Magazine and Agua LatinoAmerica Magazine, have been running pro bono WFP ads in the past several issues of both magazines and have run several stories about WFP focus countries and water projects.
The interest in expanding the partnership between WQA and WFP continues to grow and is supported by the executive directors and presidents of both organizations and a demonstrated interest by individual WQA members.
Water For People envisions a world where all people have access to safe drinking water, adequate sanitation and basic health services. A world where no child dies from a water-related disease. Thank you, Water Quality Association, for your interest in helping people help themselves.
Amy Douglas, Fund Raising Manager
Water For People