Question

The following is from a Mosquito Dunks® label. Mosquito Dunks® are used to control mosquito larvae populations in standing water.

ACTIVE INGREDIENT:

Bacillus thuringiensis var israelensis, Serotype H-14 primary powder,

7000 Aedes aegypti international toxic units (ITU) per milligram (dry weight basis) 10%

INERT INGREDIENTS................................................................................ 90%

1. The active ingredient in Bti products is a crystalline protein protoxin produced by Bacillus thuringiensis subspecies israelensis ______.

a. endospores

b. bacteria

2. Bt bioinsecticides are toxic to insect larvae that eat them, but are not toxic to humans and other animals because.....

a. the B. thuringiensis protoxin is activated only in the basic environment of the insect gut.

b. humans are much larger than insects and are less likely to be affected.

c. humans eat very little of the product, while insect larvae at a lot of it.

d. Actually, Bt insecticides are toxic when eaten by humans and other animals.

3. Nolo Bait®, which contains spores of the obligate intracellular fungus Nosema locustae, has been licensed by the EPA as a control measure for grasshoppers. Nolo Bait is also called “Grasshopper Spore.” N. locustae spores and bacterial spores are similar in all of the following ways EXCEPT:

a. Both spores are used for reproduction.

b. All of the above are true of both types of spores.

c. Both spores can remain viable in the environment for long periods of time.

d. Both spores remain inert under adverse conditions.

4. What unusual cellular characteristic does N. locustae share with the protist Mixotricha paradoxa, the organism discussed in the article “A Russian Doll of Symbiosis?”

5. Photorhabdus luminescens is perhaps the most unusual microbe yet proposed to be used as a bioinsecticide. Photorhabdus luminescens and the microscopic worm Heterohabditis bacteriophora are ______(bacteria/nematode worms/wax worms/symbionts). The P. luminescens _____(wax worm/bacterium/nematode worm) lives in a ______(wax worm/bacterium/nematode worm) host. This host then parasitizes an insect larva, and the ______(wax worm/bacterium/nematode worm) within it produce _____(toxins/bacteria/spores) that kill the _______(wax worm/bacterium/nematode worm).

6. The relationship exhibited by P. luminescens bacteria and the nematode worm Heterorhabditis bacteriophora is a good example of ________.

a. parasitism

b. mutualism

c. commensalism

Answer 1

1. The active ingredient in Bti products is a crystalline protein protoxin produced by Bacillus thuringiensis subspecies israelensis ____BACTERIAL ENDOTOXIN__.

a. endospores

2. Bt bioinsecticides are toxic to insect larvae that eat them, but are not toxic to humans and other animals because.....

a. the B. thuringiensis protoxin is activated only in the basic environment of the insect gut.

3. Nolo Bait®, which contains spores of the obligate intracellular fungus Nosema locustae, has been licensed by the EPA as a control measure for grasshoppers. Nolo Bait is also called “Grasshopper Spore.” N. locustae spores and bacterial spores are similar in all of the following ways EXCEPT:

c. Both spores can remain viable in the environment for long periods of time.

5. Photorhabdus luminescens is perhaps the most unusual microbe yet proposed to be used as a bioinsecticide. Photorhabdus luminescens and the microscopic worm Heterohabditis bacteriophora are symbionts. The P. luminescens _____bacterium lives in a ______nematode worm host. This host then parasitizes an insect larva, and the ______/bacterium within it produce _____toxins that kill the _______insect.

6. The relationship exhibited by P. luminescens bacteria and the nematode worm Heterorhabditis bacteriophora is a good example of ________.

b. mutualism