TWiV 412: WO, open the borders and rig the infection

The TWiVome reveal the first eukaryotic genes found in a bacteriophage of Wolbachia, and how DNA tumor virus oncogenes antagonize sensing of cytoplasmic DNA by the cell.

You can find TWiV #412 at microbe.tv/twiv, or listen below.

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TWiV 360: From Southeastern Michigan

On episode #360 of the science show This Week in Virology, Vincent visits the University of Michigan where he and Kathy speak with Michael, Adam, and Akira about polyomaviruses, virus evolution, and virus assembly, on the occasion of naming the department of Microbiology & Immunology a Milestones in Microbiology site.

You can find TWiV #360 at www.microbe.tv/twiv. Or you can watch the video below.

TWiV 290: Baylor goes viral

On episode #290 of the science show This Week  in VirologyVincent meets up with Janet Butel and Rick Lloyd at Baylor College of Medicine to talk about their work on polyomaviruses and virus induced stress.

You can find TWiV #290 at www.microbe.tv/twiv.

TWiV 250: Wookie viruses

On episode #250 of the science show This Week in Virology, Vincent and Robert Garcea talked about polyomaviruses. This episode was recorded at the 53rd ICAAC in Denver, Colorado.

You can find TWiV #250 at www.microbe.tv/twiv, or view the video below.

TWiV 214: This is your brain on polyomavirus

On episode #214 of the science show This Week in Virology, Vincent, Alan, and Kathy discuss how coagulation factor X binding to adenovirus activates the innate immune system, and a novel polyomavirus associated with brain tumors in raccoons.

You can find TWiV #214 at www.microbe.tv/twiv.

TWiV 160: Moore tumor viruses

merkel carcinomaHosts: Vincent Racaniello, Rich ConditAlan DoveDickson Despommier, and Patrick Moore

The TWiV team speaks with Patrick Moore about his discovery, with Yuan Chang, of two human tumor viruses, Kaposi’s sarcoma herpesvirus and Merkel cell polyomavirus.

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Click the arrow above to play, or right-click to download TWiV 160 (66 MB .mp3, 109 minutes).

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Rich – GATTACA
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Vincent – Boxwave capacitative stylus

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Neva10+1 top science apps
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Send your virology questions and comments (email or mp3 file) to twiv@microbe.tv, or call them in to 908-312-0760. You can also post articles that you would like us to discuss at microbeworld.org and tag them with twiv.

TWiV 96: Making viral DNA

Hosts: Vincent Racaniello, Dickson Despommier, and Rich Condit

On episode #96 of the podcast This Week in Virology, Vincent, Dickson, and Rich continue Virology 101 with a discussion of how viruses with DNA genomes replicate their genetic information.

Click the arrow above to play, or right-click to download TWiV #96 (65 MB .mp3, 90 minutes)

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Weekly Science Picks

Rich – Breast milk sugars give infants a protective coat (NY Times and PNAS article)
Vincent – The Great American University by Jonathan R. Cole

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TWiV 64: Ten virology stories of 2009

3D_InfluenzaHosts: Vincent Racaniello, Alan Dove, and Rich Condit

Vincent, Alan, and Rich discuss ten compelling virology stories of 2009.

Click the arrow above to play, or right-click to download TWiV #64 (68 MB .mp3, 94 minutes)

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Ten virology stories of 2009:

  1. Pandemic influenza: Swine-origin H1N1 virus (TWiV 36)
  2. XMRV, prostate cancer, and chronic fatigue syndrome (TWiV 50, 55)
  3. AIDS vaccine ‘success’ (TWiV 51)
  4. Colony collapse disorder (TWiV 46, 49)
  5. AIDS-like disease in wild chimps (TWiV 45)
  6. Diverse viral community in Antarctic lake (TWiV 58)
  7. Polyomavirus seroepidemiology in humans (TWiV 26)
  8. Poxvirus threatens UK red squirrels (TWiV 63)
  9. Polio spreads from Nigeria (TWiV 29)
  10. How mosquitoes survive Dengue virus infection (TWiV 21)

Picture book on viruses for kids (Thanks Soraia!)

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Rich Surely You’re Joking, Mr. Feynman! by Richard P. Feynman, Ralph Leighton, Edward Hutchings, and Albert R. Hibbs
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Vincent The Art and Politics of Science by Harold Varmus

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TWiV 41: Fish flu

TWiV_AA_200Hosts: Vincent Racaniello, Dick DespommierAlan Dove, and Rich Condit

On episode #41 of the podcast “This Week in Virology”, Vincent, Dick, Alan and Rich Condit chat about infectious salmon anemia virus, virus-resistant grapevines, virulence of pandemic H1N1 influenza virus, origin of 1918 influenza virus, holy water ban to halt influenza, frequency of human WU and KI polyomavirus infection, rabies in China, and host species of sin nombre virus.

Click the arrow above to play, or right-click to download TWiV #41 (51 MB .mp3, 73 minutes)

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Links for this episode:
Wal-Mart stops buying Chile salmon on virus outbreak
Virus-resistant grapevines
Virulence of H1N1 pandemic influenza virus in animal models
Did 1918 influenza virus originate in birds or not?
Holy water ban to halt swine flu
Frequent Human Infection with WU and KI Polyomaviruses
Rabies in China
Increased Host Species Diversity and Decreased Prevalence of Sin Nombre Virus
Fast, cheap PCR for crime scenes (thanks Jim!)

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Alan For Love of Insects by Thomas Eisner
Rich Making of the Atomic Bomb by Richard Rhodes
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Origin of Species by Charles Darwin
Vincent Gallileoscope (thanks Zach!)

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Merkel cell polyomavirus, a new oncogenic human virus?

merkel-cell-polyomavirusNone of the four human polymaviruses that were known in early 2008 – JC, BK, KI and WU – had been shown to cause cancer. The subsequent identification of a new polyomavirus associated with Merkel cell carcinoma demonstrates the type of evidence that is required to prove that a virus is oncogenic in humans.

Merkel cell carcinoma (MCC) is a relatively rare human skin cancer, although its incidence has increased in the past twenty years from 500 to 1500 cases per year. This cancer occurs more frequently than expected in individuals who are immunosuppressed, such as those who have received organ transplants or who have AIDS. A similar pattern of susceptibility is also observed for Kaposi’s sarcoma, a tumor that is caused by the herpesvirus HHV-8. Therefore it was suggested that MCC might also be caused by an infectious agent.

To identify the etiologic agent of MCC, the nucleotide sequence of total mRNA from several MCC tumors was determined and compared with the sequence of mRNA from a normal human cell. This analysis revealed that the MCC tumors contained a previously unknown polyomavirus which the authors named Merkel cell polyomavirus (MCV or MCPyV). The viral genome was found to be integrated at different sites in human chromosomal DNA from MCC tumors.

If MCV infection causes MCC, then the viral genome should be present in tumors but not in normal tissues. MCC DNA was found in eight of ten MCC tumors, each obtained from a different patient. The viral genome was not detected in various tissues samples from 59 patients without MCC. Furthermore, the viral genome had integrated into one site in the chromosome of one tumor and a metastasis dervied from it. This observation indicates that integration of the viral genome occurs first, before division of the tumor cells.

In subsequent studies MCV DNA has been detected in 40-85% of the MCC tumors examined. The viral DNA is not found in small cell lung carcinoma, which, like MCC, is also a neuroendocrine carcinoma. MCV particles have also been detected by electron microscopy in the cytoplasm and nucleus of tumor cells from one patient, suggesting ongoing viral replication.

How might MCV cause Merkel cell carcinoma? Expression of the viral protein known as T antigen might be sufficient to transform cells. Alternatively, integration of the viral DNA into human DNA could lead to unregulated synthesis of a protein that transforms cells. To prove that MCV causes Merkel cell carcinoma, it will be necessary to demonstrate that infection with the virus, or transfection with viral DNA, transforms and immortalizes cells in culture.

Feng, H., Shuda, M., Chang, Y., & Moore, P. (2008). Clonal Integration of a Polyomavirus in Human Merkel Cell Carcinoma Science, 319 (5866), 1096-1100 DOI: 10.1126/science.1152586

Wetzels, C., Hoefnagel, J., Bakkers, J., Dijkman, H., Blokx, W., & Melchers, W. (2009). Ultrastructural Proof of Polyomavirus in Merkel Cell Carcinoma Tumour Cells and Its Absence in Small Cell Carcinoma of the Lung PLoS ONE, 4 (3) DOI: 10.1371/journal.pone.0004958