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Biological & Biomedical Sciences
Lab Report
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Lab Report On An Experiment Carried Out About Bacterial Evolution (Lab Report Sample)


Lab report on an experiment carried out about Bacterial Evolution


Results and Discussion
Results and Discussion
In the first experiment, the inoculation at n=28 produced a distance of 789.93 mm and SEM 1.64 mm at 0.15% saline control plates. When the saline of the agar plates was increased to 15 percent, the inoculation with n=57 produced a distance of 55:46 mm and SEM of 1.53 mm. In the second experiment with the inoculation of at n=29, the distance observed was 80.90 mm with SEM of 1.64 mm. An increase in the salinity of Agar Plates to 15 percent with n=57 resulted in 60:23 mm distance and SEM of 1:55 mm. In the third experiment with n=29, the distance recorded was 82.00 mm with a SEM of 1:21 mm. In the 15 percent saline agar plates with n=57, the distance observed was 65.08 mm and SEM of 2.09 mm. The average distance for the control plates at 0.25 percent salinity was 80.61 mm and SEM of 1.57 mm. For the saline of 15 percent, agar plates, the average distance was 60.26 mm, and the SEM turned out to be 1.72 mm. Bacterial Evolution Pooled Data
Control Plates

15% Saline Agar Plates

* Inoculation 1 (n = 28)
¯ Distance: 78.93 mm
¯ SEM: 1.64 mm
* Inoculation 2 (n = 29)
¯ Distance: 80.90 mm
¯ SEM: 1.86 mm
* Inoculation 3 (n = 29)
¯ Distance: 82.00 mm
¯ SEM: 1.21 mm

* Inoculation 1 (n = 57)
¯ Distance: 55.46 mm
¯ SEM: 1.53 mm
* Inoculation 2 (n = 57)
¯ Distance: 60.23 mm
¯ SEM: 1.55 mm
* Inoculation 3 (n = 57)
¯ Distance: 65.08 mm
¯ SEM: 2.09 mm

The control plates contained 0.15% saline.
H0: E. aerogenes adapts to relatively salty environments and can grow in a higher saline environment.
H1: E. aerogenes adapts to comparatively salty conditions and fails to grow in a higher saline environment.
At the salinity of 0.25 percent, the distance observed was 80.61 mm, and that of the SEM was 1.57 mm while in the salinity of 25 percent, the distance was 60.26 mm and that of SEM 1.72. Low salinity results in a divergence of the distance and convergence of the SEM while increased salinity brings about the convergence of the distance and divergence of the SEM. For instance, in the salinity of 0.25, it is observed that the distance moved further to 80.61 mm with the SEM moved closer to 1.57 mm. Similarly, increased salinity to 25 percent resulted in the reduction of distance to 60.26 mm while the SEM moved further to 1.72 mm.
According to Kempf & Bremer (1998), all the microorganisms contain a positive turgor as well as maintenance system for the outward-directed pressure. This forms the primary basis observed in the variation of the distance and the SEM in this experiment. As noted, the exposure of the microorganisms to the osmolality environments brings about rapid fluxes out of the cell along the osmotic gradient. This results in the reduction of the turgor as well as the cytoplasm dehydration (Kempf & Bremer, 1998). The variation in salinity of the plates resulted in the differences observed amongst the distance and the SEM in this experiment.
The microorganism used in this analysis was the E. aerogenes, a non-halophilic microbe used in the indication of fecal contamination. Research has shown that the pathogenic Escherichia coli possesses high salt tolerance when compared to the non-pathogenic Escherichia coli (Goh et al., 2012). However, these microbes react in a similar manner to different salinity levels with both demonstrating a relatively high salt tolerance. Though with little differences probably due to the experimental errors, the experiment is inconsistent with literal finding where the results suggested that the Escherichia coli adapts to relatively salty environments with a monthly increment of one percent (Goh et al., 2012). Our results showed that an increase in salinity by 25 percent led to the growth of SEM to 1.72 mm from 1.57 mm.
The growth hails a research conducted by Callaway, & Kao (2014), who found out that the osmotic stress brought about by dense populations or high concentrations of osmolyte can significantly impact on the productivity and growth of microbes. The research discovered that all the isolates by a substantial extent improved growth in the selection and could be able to grow in a higher salt concentration of about 0.8 M sodium chloride (Callaway, & Kao). Errors in this experiment might have come about due to inaccurate proportions of the experimental substances and concentrations used by the members of the group.
E. aerogenes adapts to relatively salty environments and can grow in a higher saline environment. The practical implications of this experiment are of the great significance since they give a probability of future adaptations to the medical therapies. These include the treatment through antibiotics in human beings and also the techniques of food preservation.
Callaway, E., & Kao, K. C. (2014). Evolved Osmotolerant Escherichia coli Mutants Frequently Exhibit Defective N-Acetylglucosamine Catabolism and Point Mutations in Cell Shape-Regulating Protein MreB. Applied and...
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