Data Analysis: Virulence Factors & co-infection (10 pts) KEY for abbreviations:
ID: 96303 • Letter: D
Question
Data Analysis: Virulence Factors & co-infection (10 pts)
KEY for abbreviations:
SP = Phosphate buffered saline treated
hMPV –SP = human metapneumovirus infected.
ST 3 and ST 14 = Streptococcus pneumoniae strains that were isolated from clinical samples.
HEP-2 = human cervical cancer cells (HeLa contaminant – originally thought to be Larnyx tissue)
A549 = human lung carcinoma (lung cancer)
Figure 1 describes the adhesion of bacteria on human tissue culture cells. These cells were cultured with either PBS (SP) or human metapneumovirus (hMPV SP) for 48 hours. Streptococcus pneumoniae was then added, incubated for 30 minutes. The tissue culture cells were rinsed and then harvested for bacterial counts. The bacteria were counted with serial dilutions to determine CFUs.
Questions:
Why were both SP and hMPV SP groups tested?
Which cell type – Hep2 or A549 has more bacteria?
Why do you think that is the case?
Why include both absolute CFU and inoculum % adherent in this figure?
What effect does human metapneumovirus have on Streptococcus pneumoniae adhesion on these cells?
Why do you think researchers are interested in studying this phenomena?
A549 hMPV-SP A549 1500000 1000000 500000 10 ST 14 Hep2 Hep2 hMPV-SP 25 750000 15 L500000 10 ST3 ST14 Figure 1. Adherence of Streptococcus pneumoniae on human metapneumovirus (hMPV)-infected (hMPV-SP) or non-hMPV infected (SP). (A) A549; (B) Hep-2 cells. The figure shows the mean and standard deviation (positive value) of absolute colony- forming units (CFU) and inoculum percentage of adhering S. pneumoniae/10 CFU of inoculum. p 0.05 between two groups (r = 6). KFY for ahbreviationsExplanation / Answer
1) The aim of this study was to explore the effect of preceding human metapneumovirus (hMPV) inoculation on subsequent pneumococcal infection. So, both SP and hMPV SP groups were tested.
2) A549 has more number of cells.
3) This can be identified from more CFU (colony forming units) in A549.
4) Both absolute CFU and inoculum % adherent are included in the figure to find if there is any relationship between inoculum % and CFU count.
5) There was significantly enhanced bacterial adherence in A549 cells with preceding hMPV infection.
6) Researchers are interested in studying this phenomena to understand the reason behind enhanced bacterial proliferation and exacerbated histopathology in pneumococcal infection following human metapneumovirus (hMPV) infection.
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