Tips from the Journals of the American Society for Microbiology

Honeybees May Transmit Viruses to Their Offspring

Researchers from the U.S. Department of Agriculture report what may be the first evidence of queen honeybees transmitting viruses to their offspring. They report their findings in the January 2006 issue of the journal Applied and Environmental Microbiology.

Honeybees contribute greatly to the annual 15 billion dollar agriculture market by assisting in the pollination of a wide variety of crops. The health of honeybee colonies is continuously threatened by various pathogens, with viruses posing the greatest risk due to lack of information concerning transmission and outbreaks.

In the study feces and tissue (including hemolymph, gut, ovaries, spermatheca, head, and eviscerated body) of individual queen bees were tested for viral presence. All tissue forms but one, as well as feces, were found to carry viral infections. Once the viruses in the queen bees were identified, their offspring (including eggs, larvae and adult workers) were tested and found to carry the same viruses.

"The present study, using the sensitive RT-PCR method, demonstrated the vertical transmission of multiple viruses from mother queens to their offspring by two findings: first, the presence of viruses in queen excretion and queen tissues, particularly in the tissue of ovaries; and second, detection of the same viruses in queens' eggs and young larvae that are not normally associated with V. destructor, which is an important vector of bee viruses," say the researchers.

(Y.P. Chen, J.S. Pettis, A. Collins, M.F. Feldlaufer. 2006. Prevalence and transmission of honeybee viruses. Applied and Environmental Microbiology, 72. 1: 606-611.)

Slugs May Spread E. coli to Salad Vegetables

A new study suggests that slugs have the potential to transmit E. coli to salad vegetables. Researchers from the University of Aberdeen, United Kingdom, report their findings in the January 2006 issue of the journal Applied and Environmental Microbiology.

Escherichia coli O157, an emerging zoonoses in many countries including the U.S. and U.K., has a 3 to 5 percent mortality rate in humans. Farm animals such as cattle and sheep have been previously identified as major reservoirs of this strain of E. coli by passing it through manure which is then used to fertilize crops. Slugs are widespread agricultural pests that continuously ingest bacteria from the soil and their environment. Their tendency to contaminate leafy vegetables often targeted for human consumption identifies them as likely source for E. coli transmission.

Laboratory testing found E. coli O157 in 0.21 % of field slugs on a sheep farm in the UK. Further studies revealed that the slug species, Deroceras reticulatum, could maintain viable E. coli on its external surface for 14 days and slugs that were fed E. coli shed viable bacteria in their feces persisting for up to 3 weeks.

"This study provides evidence that slugs can act as vectors of E. coli O157 from an environmental source to fruit or vegetables," say the researchers. "The research demonstrates that E. coli in D. reticulatum has a relatively long external and internal survival time and also shows that ability of E. coli to persist at length in excreted slug feces."

(E.L. Sproston, M. Macrae, I.D. Ogden, M.J. Wilson, N.J.C. Strachan. 2006. Slugs: potential novel vectors of Escherichia coli O157. Applied and Environmental Microbiology, 72. 1: 144-149.)

Epstein-Barr Virus Found in Breast Cancer Tissue May Impact Efficiency of Treatment

Epstein-Barr virus has been detected in breast cancer tissue and tumor cells and may impact the efficiency of chemotherapeutic drug treatment say researchers from France and Japan. They report their findings in the January 2006 issue of the Journal of Virology.

A ubiquitous human herpesvirus, the Epstein-Barr virus (EBV), has been previously linked to skin and gastric cancer, as well as cancer of the salivary glands and thymus. New studies have detected EBV in breast cancer specimens and have prompted researchers to examine the effect of infection with EBV on anticancer drug treatment.

In the study biopsy specimens of breast cancer tissue and tumor cells were tested for the EBV genome. The genome was identified in about half of the specimens, however the viral load was highly variable from tumor to tumor. These findings indicate that although EBV isn't likely to cause breast cancer, it may contribute to tumor progression. In addition, researchers studied the EBV infected cells in vitro and found that the virus may contribute to the resistance of paclitaxel (taxol), chemotherapy commonly used in the treatment breast cancer, and cause overexpression of the multidrug resistance gene (MDRI).

"Consequently, even if a small number of breast cancer cells are EBV infected, the impact of EBV infection on the efficiency of anticancer treatment might be of importance," say the researchers.

(H. Arbach, V. Viglasky, F. Lefeu, J.M. Guinebretiere, V. Ramirez, N. Bride, N. Boualaga, T. Bauchet, J.P. Peyrat, M.C. Mathieu, S. Mourah, M.P. Podgorniak, J.M. Seignerin, K. Takada, I. Joab. 2006. Epstein-Barr virus (EBV) genome and expression in breast cancer tissue: effect of EBV infection of breast cancer cells on resistance to paclitaxel (Taxol). Journal of Virology, 80. 2: 845-853.)

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