Certain types of hormone treatments may increase a woman's risk of contracting genital herpes say researchers from McMaster University in Ontario, Canada. Their findings appear in the April 2003 issue of the Journal of Virology.
In the study, mice were injected with two types of hormone treatment and then inoculated with a strain of the herpes simplex virus type 2. The mice that received Depo-Provera, a common form of birth control, showed no immune response protecting against the virus. Those that received a saline suspension of progesterone were able to ward off infection.
"The results clearly show that, depending on the hormone treatment, susceptibility of mice to genital herpes infection can vary significantly," say the researchers. "Depo-treated mice are the most susceptible and remain so for prolonged periods of time."
(C. Kaushic, A. A. Ashkar, L. A. Reid, K. L. Rosenthal. 2003. Progesterone increases susceptibility and decreases immune responses to genital herpes infection. Journal of Virology, 77. 8: 4558-4565.)
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BACTERIA PROTECT ANCIENT STONEWORK
Researchers from the University of Granada, Spain, have identified a strain of bacteria that may help protect stone monuments and statues from pollution-induced erosion. They report their results in the April 2003 issue of the journal Applied and Environmental Microbiology.
"Architectural and sculptural stone undergoes deterioration due to physical, chemical and/or biological weathering. The composition and textural characteristics of carbonate stones (limestones, dolostones and marbles) make them particularly susceptible to weathering. Increasing atmospheric pollution has accelerated deterioration of carbonate stones in recent decades," say the researchers.
Over the years, conservation strategies for these stones have fallen into two categories. Protection involves the external treatment of the stone to prevent weathering agents from getting inside the stone. Consolidation involves the impregnation and strengthening of the stone with a cement or hardening product.
The researchers have identified a strain of bacteria, called Myxococcus xanthus, that can grow inside the pores of carbonate stones and produces calcium carbonate which adheres to the inside the pores and strengthens the stone.
"Our study demonstrates that biomineralization induced by bacterial activity results in significant protection and consolidation of porous carbonate stones used in sculptural and architectural heritage," say the researchers.
(C. Rodriguez-Navarro, M. Rodriguez-Gallego, K.B. Chekroun and M.T. Gonzalez-Munoz. 2003. Conservation of ornamental stone by Myxococcus xanthus-induced carbonate biomineralization. Applied and Environmental Microbiology, 69: 2182-2193.)
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VACCINE KILLS MOSQUITOES
Researchers from Tulane and Case Western Reserve Universities have developed a novel method for controlling malaria transmission. In the April 2003 issue of the journal Infection and Immunity, they present research suggesting the possibility of a vaccine that makes the recipient toxic to mosquitoes.
In the study, researchers inoculated mice with DNA taken from the midgut of the mosquito Anopheles gambiae, a common carrier of malaria, and then allowed live mosquitoes to feed on the mice. After seven days they observed an increased mortality in the mosquitoes that fed on the immunized mice compared to mosquitoes that fed on control mice.
"Our results demonstrate that host immunization with specific mosquito midgut cDNAs can induce an immune response that is lethal to bloodfeeding mosquitoes," say the researchers. "When mosquitoes feed on immunized animals, a spectrum of immune factors is ingested and all may act separately or synergistically to impair the insect."
(B.D. Foy, T. Magalhaes, W.E. Injera, I. Sutherland, M. Devenport, A. Thanawastien, D. Ripley, L. Cardenas-Freytag and J.C. Beier. 2003. Induction of mosquitocidal activity in mice immunized with Anopheles gambiae midgut cDNA. Infection and Immunity, 71: 2032-2040.)