Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PDF of PowerPoint - Lehigh University
Document related concepts
Canine parvovirus wikipedia , lookup
Swine influenza wikipedia , lookup
Marburg virus disease wikipedia , lookup
Elsayed Elsayed Wagih wikipedia , lookup
Canine distemper wikipedia , lookup
Hepatitis B wikipedia , lookup
Avian influenza wikipedia , lookup
Orthohantavirus wikipedia , lookup
Henipavirus wikipedia , lookup
Transcript
J. A. Sands, 12 October 2009 Lehigh University Abstract Infectious diseases caused by bacteria or viruses have resulted lt d iin pandemics d i th thatt h have repeatedly t dl played l d major j roles in human history. While bacteria are single-celled single celled organisms able to reproduce if they have the proper nutrients and environment, viruses are biological entities that are on the borderline of life life. Viruses are “particles”, able to reproduce very rapidly but onlyy when they y are inside susceptible p host cells. In this lecture, we will look at an overview of how viruses replicate, how they evolve, and how some of them, such as influenza and HIV HIV, can cause pandemics pandemics. Electron Micrographs of Viruses A. Bacteriophage T4 B. Potato virus X C. Adenovirus D. Influenza virus Properties and Reproduction of Viruses Properties of Animal Viruses Enveloped or non-enveloped. Variety of entry mechanisms. Shown here is the simplest possible virus replication cycle. No real viruses are this simple. The list on the right indicates some of the complexities and variety seen in the viruses that infect animals, including us. Genome can be DNA or RNA. Number of genes from about 5 to over 100. G Genome replication li ti iin nucleus l or cytoplasm. Replication and transcription usually b viral by i l enzymes. Translation by cellular ribosomes. V i t off assembly Variety bl mechanisms. h i Release by cell lysis or by budding. 06 39 retrovirus jpg 06_39_retrovirus.jpg In the nucleus During transport towards nucleus In cytoplasm At cell surface Replication cycle of HIV Budding through plasma membrane HIV-1 M group evolution since ~ 1930 HIV has undergone rapid evolutionary divergence since its introduction into humans from chimpanzees. Influenza has also undergone significant evolutionary change over the past century, but in a different way than HIV. The Influenza Virus Genome Consists of Eight Separate Pieces of RNA. Neumann et al., Nature 459: 931 (2009) If two different influenza viruses enter the same cell, “reassortment” might produce a new virus containing RNA from both parental viruses. Neumann et al., Nature 459: 931 (2009) Neumann et al., Nature 459: 931 (2009)
