What are the two ways S. gordonii inhibits competitors?

What are the two ways S. gordonii inhibits competitors?

• A. Sugar consumption and hydrogen peroxide production
• B. Quorum sensing interference and antibiotic production
• C. Acid production and motility
• D. Biofilm detachment and spore formation

Answer: (A)

The main idea here is how a mouth-dwelling microbe can suppress neighbors through both competition for nutrients and chemical inhibition. Streptococcus gordonii helps its own position by grabbing available sugars, leaving fewer resources for other bacteria to grow. At the same time, it produces hydrogen peroxide when oxygen is present. This hydrogen peroxide diffuses into nearby cells and causes oxidative stress, which inhibits or slows the growth of susceptible competitors, such as cariogenic species like Streptococcus mutans. So, the two ways it inhibits others are consuming sugars (resource competition) and generating hydrogen peroxide (chemical antagonism). Other options don’t fit as well because they describe mechanisms not typically associated with S. gordonii’s antagonism: quorum sensing interference and antibiotic production aren’t its hallmark defenses; acid production and motility aren’t the primary established means of inhibiting neighbors in this context; and biofilm detachment and spore formation aren’t characteristic features of Streptococcus species.

The main idea here is how a mouth-dwelling microbe can suppress neighbors through both competition for nutrients and chemical inhibition. Streptococcus gordonii helps its own position by grabbing available sugars, leaving fewer resources for other bacteria to grow. At the same time, it produces hydrogen peroxide when oxygen is present. This hydrogen peroxide diffuses into nearby cells and causes oxidative stress, which inhibits or slows the growth of susceptible competitors, such as cariogenic species like Streptococcus mutans. So, the two ways it inhibits others are consuming sugars (resource competition) and generating hydrogen peroxide (chemical antagonism).

Other options don’t fit as well because they describe mechanisms not typically associated with S. gordonii’s antagonism: quorum sensing interference and antibiotic production aren’t its hallmark defenses; acid production and motility aren’t the primary established means of inhibiting neighbors in this context; and biofilm detachment and spore formation aren’t characteristic features of Streptococcus species.