Bio Lecture Week 6 10 07 2014 Virus type tells you what host range is How it infects potential new hosts Example A Fujian 411 2002 H3N2 Virus type Geo origin Strain Year of isolation Virus subtype HIV Human immunodeficiency virus AIDS RNA envelope virus 2 identical strands o covered with glycoprotein spikes gp120 gp120 attaches to receptors on host cell o CD4 CCR5 receptors HIV attacks T cells type of white blood cell Process o Critical part of immune system o Over time T cells die body becomes less resistant to viruses o Can be infected with HIV and not have AIDS Can be dormant in body for up to 20 years o HIV enters cell based upon receptor recognition o Once inside capsid breaks down releases RNA into cytoplasm RNA reverse transcriptase enzyme Combination makes it a retrovirus Forms DNA producing double stranded DNA copy of RNA Where any mutation will occur Goes into nucleus where it inserts itself into host cell genome Now is carrying HIV anywhere it goes Known as provirus RNA replicated leaves nucleus to infect more T cells HIV will never leave your system Treatments o No vaccines so far o When coming up with treatments you want target important structures processes that will harm crucial part of virus o Different treatments Entry inhibitors Block binding of gp120 receptors so there is no way of getting into cell Block fusion of viral envelope with cell membrane Gene therapy With this particular mutation become immune to virus RT inhibitors Block DNA provirus synthesis Inhibiting action of RT If you block this they can t replicate or produce double strand DNA AZT NRTI groups about blocking RNA synthesis Protease inhibitors Target virion building stage o Found that none of the inhibitors can make a huge difference o Came up with Combo Treatment cocktail Treating all different aspects of inhibitors Could greatly reduce mortality rates Lots of side effects but less chance of death Ebola Filovirus o Filamentous structure thread like Helical capsid RNA Surrounded by lipid membrane with glycoprotein studs Studs used for host recognition cell invasion o Deadliest of all viruses Hemorrhagic fever o Multiple organ dysfunction syndrome begin to break down o Central nervous system digestive circulatory etc Retrieve by close contact only transferred from contact o With blood feces vomit from infected individual o Must be taken in through mouth nose eyes cuts Likely reservoir species where it originated o Fruit bats o Bats don t typically get infected bc of naturally high body temperature How did this transfer from bats to humans o Bats ate fruit messy eaters dropped partial eaten fruit on ground that other animals later consumed Gorillas Chimps Poached Duikers Hunted Hunted poached humans come into contact with blood SARS Severe Acute Respiratory Syndrome RNA envelope virus Respiratory virus Can be spread through the air Originated in Asia spread quickly to other countries High mortality rates 10 of infected die Rapid mutation lead to it dying off Civets cat foxes in Asia carry SARS and die from it o Transferred to human populations o Beans are roasted from Civet s feces and cooked for human consumption Hantavirus RNA virus Southwestern US Attacks respiratory system and kidney systems Spread of disease becomes problematic depending on climate o Increased rain increased food for rodents increase of mice chipmunks carrying hantavirus o Increased chance of coming in contact with humans spreading infection Feces urine from rodents that has been aerosolized gets into air Cycles with weather Pox Viruses DNA viruses Lower error rates during replication lower mutation rates Not constantly dealing with new strains Envelope virus not all RNA Contains capsid Virophages viruses that infect viruses Amoeba mamaviruses o Infection greatly reduced amoeba survival and reproduction o There were smaller viruses inside mamaviruses and the ameoba s cytoplasm o Small icosahedral virions o MV replication 3fold amoeba death o 70 decrease in MV infection o greatly increased amoeba growth without MV Sputnik meaning to travel within Prokaryotes Domain Bacteria Bacteria o Ester bonds in membranes o Peptidoglycan cell wall structure o Unique simple system with protein synthesis o Lacks exons introns Domain Archaea Archaebacteria o Ether bonds in membranes more stable than ester bonds and tough to break down o Have no peptidoglycan material o Use exons introns o Alter pattern of gene expression o Results in different protein produced o FOUND EVERYWHERE o No parasites of pathogens o Many found in normal environmental conditions o Extremophiles Lovers of extreme conditions Same symbioses mutualism and commensalism o Thermophiles Hot springs deep sea thermal vents Heat stable enzymes o Thermus aquaticus From Yellowstone Nat park Heat stable enzyme o Hyperthermophile Heat stable enzyme with tungsten o Acidophiles o Halophiles Do well below pH 2 in acidic aquatic and terrestrial Increased salinity Great Salt Lake dead sea Maintain normal osmotic pressure Halophile genes allow increased survival under saline conditions o Methanogens gas Produce increased methane atmospheric greenhouse Wetlands produce large portion of world s methane Cow intestines increased methanogens Termite guts Common in trash dumps Lack membrane bound nucleus Prokaryote fossil o 3 8 BYA Anoxic Period o Complex lipids found in modern bacteria present in fossils o Evidence for carbon fixation o Resembles modern filamentous bacteria Most abundant life forms on Earth Living systems would collapse without them Bacteria and Archaea are simple organisms morphologically Bacillus rod shaped Coccus Spherical Spirillium spiral helical Use biochemical genetic comparisons to determine prokaryote diversity 10 07 2014 10 07 2014
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