News Release

Tips from the Journals of the American Society for Microbiology

Peer-Reviewed Publication

American Society for Microbiology

Not All UV Light Effective in Treating Drinking Water

Researchers from the University of Waterloo in Ontario, Canada have determined that some types of ultra violet light are not effective in killing harmful bacteria in drinking water. Their results appear in the July 2002 issue of Applied and Environmental Microbiology.

In the study the researchers tested the ability of Escherichia coli to repair DNA damage caused by varying levels of UV radiation from low and medium pressure lamps. They found that while E.coli was able to fully repair damage done to its DNA after being subjected to low-pressure UV rays, they remain unclear as to the effects of medium-pressure rays.

"The results of this study show that polychromatic medium-pressure UV radiation may offer an advantage over monochromatic low-pressure UV radiation in lower-dose water treatment applications," claim the researchers. "It is recommended that further studies be carried out with medium-pressure UV to determine which wavelengths cause additional damage and where the damage is induced."

(J. L. Zimmer and R. M. Slawson. 2002. Potential repair of Escherichia coli DNA following exposure to UV radiation from both medium- and low-pressure UV sources used in drinking water treatment. Applied and Environmental Microbiology, 68: 3293-3299.)

Bacteria Could Be New Meningococcal Vaccine

A harmless bacteria can elicit an immune response that protects against a common cause of bacterial meningitis and could serve as a potential vaccine against the disease, say researchers from the United Kingdom. Their findings appear in the July 2002 issue of the journal Infection and Immunity.

Neisseria lactamica is a bacterium that does not cause human disease, but closely resembles Neisseria meningitidis, one of the causes of bacteria meningitis. Previous studies have suggested that the development of natural immunity to menigococcal disease results from colonization of the nasal cavities by harmless Neisseria bacteria, particularly N. lactamica.

"The present study explores experimentally the hypothesis that immunization with N. lactamica can mimic infection by and enhance natural immunity to the meningococcus," say the researchers. In the study mice that were immunized with killed N. lactamica bacteria were protected from lethal infection by a number of strains of menigococcal bacteria. "The results confirm the potential of N. lactamica to form the basis of a vaccine against meningococcal disease."

(K.J. Oliver, K.M. Reddin, P. Bracegirdle, M.J. Hudson, R. Borrow, I.M. Feavers, A. Robinson, K. Cartwright and A.R. Gorringe. 2002. Neisseria lactamica protects against experimental meningococcal infection. Infection and Immunity, 70: 3621-3626.)

Immune Cells in Breast Milk Protect Infants from HIV

Scientists have found immune cells in the milk of HIV-infected mothers that target and kill the virus. This finding, which could help explain the low transmission rate from mother to child via breastfeeding despite high levels of the virus in mother's milk, appears in the August 2002 issue of the Journal of Virology.

Researchers from the University of Alabama at Birmingham, the Zambia Exclusive Breast-Feeding Study, Boston University and Columbia University tested breast milk cells (BMC) from HIV-infected women in the United States and Africa for their ability to identify and respond to components of the AIDS virus. While BMC's from all of the HIV-infected women reacted to the HIV proteins, there was no reaction from the cells from the uninfected women.

Further tests revealed that the responses were due to the presence of immune cells known as CD8+ T cells, the same immune cells that play a critical role in controlling HIV levels in the blood.

"These studies provide evidence that maternally derived T cells make their way into the infant's circulation and potentially protect the infant via adoptive transfer of maternal T cells," say the researchers. "In addition to the protection these cells may afford the neonate, we speculate that they may also be acting locally to reduce the viral load in breast milk, lowering the viral burden, and potentially decreasing transmission to newborns from their HIV-infected mothers."

(S. Sabbaj, B.H. Edwards, M.K. Ghosh, K. Semrau, S. Cheelo, D.M. Thea, L. Kuhn, G. D. Ritter, M.J. Mulligan, P.A. Goepfer, and G.M. Aldrovandi. 2002. Human immunodeficiency virus-specific CD8+ T cells in human breast milk. Journal of Virology, 76: 7365-7373.)

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Full copies of all above articles can be accessed through the ASM website at http://www.asmusa.org/pcsrc/tip.htm.


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