Part of the success of the Streptococcus pyogenes bacterium lies in its ability to evade phagocytosis. Which of the following helps in this evasion?
AStreptolysin S
BStreptolysin O
CStreptokinase
DM protein
EPyrogenic toxin
A virology student is asked to identify a sample of virus. When subjected to a nonionic detergent, which disrupts lipid membranes, the virus was shown to lose infectivity. The student then purified the genetic material from the virus and subjected it to treatment with RNase, an enzyme that cleaves the phosphodiester linkages in the RNA backbone. A minute amount of the sample was then injected into a human cell line and was found to produce viral particles a few days later. Which of the following viruses was in the unknown sample?
ATogavirus
BHepevirus
CCalicivirus
DAdenovirus
EHerpesvirus
An outbreak of diphtheria has occurred for the third time in a decade in a small village in South Africa. Diphtheria is endemic to the area with many healthy villagers colonized with different bacterial strains. Vaccine distribution in this area is difficult due to treacherous terrain. A team of doctors is sent to the region to conduct a health campaign. Toxigenic strains of C. diphtheria are isolated from symptomatic patients. Which of the following best explains the initial emergence of a pathogenic strain causing such outbreaks?
AInfection with a lytic phage
BConjugation between the toxigenic and non-toxigenic strains of C. diphtheriae
CSuppression of lysogenic cycle
DLysogenic conversion
EPresence of naked DNA in the environment
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