Polio invasion is seen in this learn node illustration. The little purple ball – lower center in this image – is a very scary thing. It is polio entering a person’s gut. Good public health can prevent polio and many other human miseries. Superb learning materials for public health practitioners are available as open education resources OER at Johns Hopkins Bloomberg School of Public Health. The image above combines slides 26-28 from an OPENCOURSEWARE course on Public Health Biology. The exact location for these OER lectures, which are open for you to download, is: Module 2: Pathogens and Host Immunity > Lecture 3: Pathogens: Nature and Transmission. This is the text that accompanies the illustrations above:
Poliovirus Viron (left image):
30 nM diameter virion contains 60 copies each of four proteins (encoded in the viral RNA) – Viral RNA is a single strand mRNA (+) polarityi, is about 8000 bases long, and encodes 11 proteins – Viron is non-enveloped and contains no enzymes
Poliovirus: Intracellular Replication (right image):
1. Attachment to cell via specific receptor (Vpr) on cell membrane 2. Virus entry (endocytosis); extrusion of RNA into cytoplasm 3-5. Translation of viral RNA; processing of polyprotein; formation of RNA replicase protein 8-10. Replication of viral RNA 11. Continued translation and processing; formation of virion proteins 12. Assembly of (+) RNA and rivon proteins into new virions 13. Virion release into the gut
MORE POLIOVIRUS LEARN NODES:
For more about the ongoing fight against polio, the Stony Brook University School of Medicine published an open access article in Virology Journal: “Epidemics to eradication: the modern history of poliomyelitis.”
For a look at sleuths who are tracking the polio viruses as they invade our cells try this open access article from the Public Library of Science BIOLOGY: “Imaging Poliovirus Entry in Live Cells.”
More learn nodes at: learnodes.com