Question

Caenorhabditis elegans is a species of soil-dwelling nematode (roundworm) that feeds on soil bacteria, including Bacillus thuringiensis. B. thuringiensis is a virulent bacterial pathogen that produces BT toxin, a protein that can kill different invertebrate species, including C. elegans. In a laboratory experiment, C. elegans and B. thuringiensis were cultured individually (control) or together (experimental) for 150 days. Under optimal conditions, the generation time of C. elegans is approximately 3.5 days and the generation time of B. thuringiensis is approximately 25 minutes. At the end of the experiment, the change in virulence of B. thuringiensis and the change in resistance of C. elegans to BT toxin were determined. The researchers found that after 150 days, the magnitude of the change in both B. thuringiensis virulence and C. elegans resistance was less when they were cultured individually (control) than when they were cultured together (experimental). Provide ONE reason for the difference in results between the two treatments.

Answer 1

i).number of generations that is possible in individual cultures of C. elegans is 42 .

ii)number of generations that is possible in individual cultures of B elegans IS 8640.

b). When the Caenorhabditis elegans and bacillus thuringiensis have controlled growth their are no immune response to each other hence they are not adapted to each other for separate growth.

c)The relative change in B. thuringiensis virulence was greater than the relative change in C. elegans resistance because B thuringiensis had more number of generation event 8640 after 150 days while C elegans had less number of reproductive event 42.

Step-by-step explanation

explanation.

a) i).number of generation for C elegans will be given by;

growing period divided by generation time.

we have ;

generation time is 3.5 day

growing period is 150 day.

then number of generation of c will be;

150/3.5=42 generation

ii).number of generation for B thuringiensis is given by;

but we have;

generation time is 25 minutes

growing period is 150 days.

then substituting in the formulae we have ,

150 x24 x60/25=8640 generation.

we have used the relation ;

1 hour =60 minutes and 1 day = 24 hours

b).When the Caenorhabditis elegans and bacillus thuringiensis have controlled growth their are no immune response to each other hence they are not adapted to each other for separate growth. when grown together they provide the host pathogen relationship protecting the growth for each organism. B thuringiensis secrets toxin to infect the host hence having much change while C elegans are protected from this chemical since the change is high.

c).The relative change in B. thuringiensis virulence was greater than the relative change in C. elegans resistance because B thuringiensis had more number of generation event 8640 after 150 days while C elegans had less number of reproductive event 42.

B. thuringiensis have smaller genome size hence have more change .This change is caused when trying to infect C elegans hence causing a more diverse change in B thuringiensis.

C elegans genome are relatively high since they have less number of reproductive event hence being protected because they produce the immune response by growing together to show maximum changes when separately grown.