Protist
Which pathogen is often controlled by beneficial bacteria? A. Fungus B. Virus C. Antibiotics D. Protist
The Correct Answer and Explanation is:
Correct Answer: D. Protist
Beneficial bacteria play a crucial role in controlling various harmful microorganisms, including protists. Protists are a diverse group of eukaryotic microorganisms, some of which can cause diseases in humans, animals, and plants. Common disease-causing protists include Plasmodium (which causes malaria), Giardia (which causes giardiasis), and Entamoeba histolytica (which causes amoebic dysentery).
One of the ways beneficial bacteria help control protists is through competitive exclusion. This occurs when harmless or beneficial bacteria outcompete harmful protists for nutrients and living space in environments like the gut. For example, a healthy gut microbiome, rich in beneficial bacteria such as Lactobacillus and Bifidobacterium, can prevent protist pathogens from establishing infections by creating an unfavorable environment for them.
Another mechanism is the production of antimicrobial substances by beneficial bacteria. These substances can inhibit or kill protists directly. For instance, some strains of Bacillus and Streptomyces bacteria produce natural antibiotics and enzymes that can target protist membranes or interfere with their metabolic processes.
In agriculture, beneficial bacteria are also used as biological control agents to manage protist infections in plants. Certain bacteria like Pseudomonas fluorescens can suppress plant pathogens, including protists such as Phytophthora and Plasmodiophora, which cause root rot and clubroot diseases.
It’s important to note that while antibiotics (answer C) are used to kill bacteria, they are not effective against protists, which are eukaryotic and structurally different from bacteria. Fungus (A) and virus (B) are also not primarily controlled by beneficial bacteria in the same way protists are.
In conclusion, beneficial bacteria play an essential protective role in various ecosystems, including the human body, by helping to regulate and reduce harmful protist populations, making D. Protist the correct answer.
