Please answer all. Will rate Question 3. Intertidal mussels, Mxtihus.trassulus,
ID: 280306 • Letter: P
Question
Please answer all. Will rate
Question 3. Intertidal mussels, Mxtihus.trassulus, collected from the same site in Washington, USA, in February and August were exposed for 2 h to different temperatures in the lab. Dissected gill tissue was then metabolically labeled at 13°C in the presence of 35S-labelled methione/cysteine before proteins were separated on 10 % SDS-polyacrylamide gels and imaged using standard fluorographic techniques. Individual lanes were loaded with equal counts of radioactivity (3.7'107 BQ), and the locations of molecular mass markers (not shown) are indicated on the right. Visible bands are indicative of protein expression; the darker the band, the more protein expressed. Heat-shock temperature (°C) 20 23 25 28 200 kDa 90 kDa 70 kDa> 40 kDa February August A. What is/are the independent and dependent variable(s) in this study? B. In response to thermal stress, many organisms increase their production of heat shock proteins, including Hsp70, a 70 ?Da molecular chaperone that functions to stabilize other proteins. What do the above results tell us about the relative stress experienced by mussels in the different treatment groups? C. Based on these results, when are mussels from this location most physiologically resistant to high temperature stress? When are they most likely to experience high temperature stress? D. Given that mussels can live for 10+ years, what is the likely biological mechanism underlying these results (i.e., this would be an example of what phenomenon)?Explanation / Answer
A. Temperature is the independent variable and heat shock protein expression (one that expresses more at higher temperature ) is the dependent variable.
B. The heat shock expression depends upon the in lab temperature (temperature exposed) as well as seasons. The expression of heats shock protein is more at 28C along with other proteins which come at molecular weight <70 but >40 Kda as well as proteins in range 20 KDa. The relative stress is more in mussels obtained in the month of august compared to feb as other heat shock proteins are also expressed along with Hsp70.
C. The mussels will be more physilogically stressful during peak summers say 28-35 C and they are more likely to be less stressful during moderate climate (say temperatures 5C-20C).
D. Longevity depends upon several factors like sexual differences, temperature fluctuations, defense mechanism of mussels etc. Mussels generally survive well at temperature 5 to 20 C . Few mussels can live upto 40 years due to stringent defense mechanism it has. Mussels have pattern like recognition receptors like RIG 1 receptors that can help it to be successful against nvading pathogens. Apart from that expression of heat shock proteins in a timely manner upon exposure to high temperatures also play a signficant role in improving the lifespan of a mussel