Talk:CH391L/S13/Gas Vesicles

• Kevin Baldridge 17:30, 1 April 2013 (EDT):anabaena flos-aquae, that's an oorganism? It should be italicized if so
• Kevin Baldridge 17:33, 1 April 2013 (EDT):Your chart of the ELISA results for TNP needs some explanation. What is the difference between the four TNP samples? Citation for the chart?
  • Yunle Huang 14:00, 7 April 2013 (EDT):Thanks, I added an explanation to the graph with a hover-over.
• Kevin Baldridge 17:35, 1 April 2013 (EDT):Any evidence for the gas vesicle display of antigens being any more or less effective than traditional attenuated/dead pathogen approaches to immunization?
  • Yunle Huang 14:00, 7 April 2013 (EDT):I couldn't find anyone else doing vaccine studies with gas vesicles, but the same people did further studies here and here. However it doesn't look like they compared gas vesicles vs. traditional vaccines. The main benefit of using these presentation systems is to avoid reversion to an infectious state.
  • Benjamin Gilman 16:31, 3 April 2013 (EDT): I was also wondering what the reasoning behind attaching an antigen to a gas vesicle was and the page should explain this. Is it to prevent degradation or excretion of the antigen? If so, how long do these gas vesicles remain in the blood and could they present other problems (like aggregation)?
    • Yunle Huang 22:55, 7 April 2013 (EDT):According to this review, delivery vehicles are used to prevent degradation and also because only particles of certain size have efficient immunogenicity.
• Gabriel Wu 19:20, 3 April 2013 (EDT): What's known about the proteins that make up gas vesicles? Are there many different kinds of subunits? How do they assemble?
  • Yunle Huang 16:19, 7 April 2013 (EDT):Gas vesicle morphogenesis is still unknown. However, we do know that the gas vesicle wall is mostly comprised of GvpA, which forms a rib-like structure. Another protein, GvpC, attaches to the exterior of the wall acts as the glue that holds together GvpA.
• Aurko Dasgupta 00:18, 5 April 2013 (EDT): The graph on immunization status feels a little dishonest. By counting every mouse as a separate bar, instead of grouping them together and using error bars, their presenting their study as more thorough that it actually was. Also, did the 4th mouse die between the 2nd booster and the 8th month?
  • Yunle Huang 16:31, 7 April 2013 (EDT):I agree that the presentation was a bit disingenuous. They did not mention the 4th mouse. However, since mice have very short lifespans (about a year in the wild) it probably did die in the 8 month waiting period.
• Max E. Rubinson 00:11, 5 April 2013 (EDT): How are gas vesicles formed in response to low light conditions in cyanobacteria? They must somehow be able to upregulate gene expression in response to low light.
  • Max E. Rubinson 00:34, 5 April 2013 (EDT): I was wondering if maybe the expression of gas vesicles in flos-aquae remains constant, and buyoancy is attenuated solely by an increase in carbohydrate concentration due to increased rates of photosynthesis at the surface, but in the 1994 review from Walsby, there is a section discussing the fact that increased gas vesicle content in flos-aquae and other species correlates with decreased photon irradiance.
    • Yunle Huang 18:58, 7 April 2013 (EDT):I couldn't find an article that describes the exact pathway in cyanobacteria, but Walsby later states in that paper, "it is uncertain whether this [gas vesicle increase] is caused by an increase in the rate of gas vesicle formation". It could be that gas vesicle production is constant since he then says that "some gas vesicles may be collapsed by rising turgor pressure at high irradiance", suggesting that regulation may not necessarily be through upregulation of gene expression.
• Thomas Wall 00:21, 5 April 2013 (EDT): If gas vesicles are how prokaryotes regulate depth in the water column, how do Eukaryotic algae perform the same tasks since they don't contain gas vesicles?
• Catherine I. Mortensen 01:45, 5 April 2013 (EDT):What exactly makes the inside of the cell hydrophobic? Why would water evaporate inside cell?
  • Yunle Huang 17:29, 7 April 2013 (EDT):The gas vesicle wall is made up of a single layer of GvpA, and the inner side of the protein is hydrophobic. The reason why water droplets can't form inside the vesicle is that water droplets have a higher vapor pressure than water in a surface, so water droplets will condense on the outside first. The Walsby review has a calculation in the "Surface Properties of the Gas Vesicle" section that shows why vapor pressure of a droplet is higher than that of a surface.
• Siddharth Das 13:50, 8 April 2013 (EDT): You said "Haloferax mediterranei, produces gas vesicles only when salt concentrations are high". Is their a transduction system that mediates this?