Enzyme Experiment Involving Softshell Clams
Abstract
An experiment was done in order to test the absorbance in the stomach of Mya arenaria when dealing with a starch present. Crystalline styles from the stomachs of the clams were used to measure the absorbance and the absorbance was measured using a spectrophotometer. The results showed that the clams were absorbing more in a pH of 6 and a lack of activity in other pH levels. After seeing the results from this experiment, there could be an experiment as to why clams don’t have more activity in other pH levels since they live in the rocky intertidal and are subject to changes all the time and are sometimes exposed to other pH level water.
Introduction
This experiment was done to study how enzymes in the stomach of Mya arenaria react in different pH levels compared to human enzymes. Along with that, there was a study done on whether or not the rate differs based on how inter and intracellular environmental conditions can affect the rate of enzyme activity. Mya arenaria is found generally in brackish water and estuaries (MacLean et al.) so there is a possibility of pH levels changing depending on where they were located. The pH levels tested were pH 6, pH 7, and pH 8. To find our data, the absorbance was measured of each sample in a spectrophotometer. We hypothesize that the pH will affect the rate and that the absorbance will be the greatest when dealing with a pH of 6 in the clams and at a pH of 7 for the human saliva.
Materials and Methods
In order to get the data, the crystalline style had to be extracted from the stomach of the clam. The crystalline style releases enzymes into the stomach of the clam to help break down the food in their stomach. It was determined that the stomach and crystalline style was the best place to help determine enzyme activity (Lavine et al.) The anterior and posterior muscles on the clam so that there would not be a risk of breaking the crystalline style. Twelve styles were used in this experiment. In order to be able to get the measurements, a centrifuge was needed to separate the dirt used when grinding up the styles in order to mix them with starch amylase. At the same time there was human saliva collected to test alongside the clam styles. For a total of 7 centrifuge tubes, there were 3 clam tubes, with varying pH levels, 3 saliva tubes with human saliva at varying pH levels, and a control tube. After the centrifuge completed its job, the solutions in the tubes were put into a spectrophotometer and results were recorded.
Results
Figure 1. Â Differences in values for the different clam amylase experiments.
Figure 2. Differences in each of the absorbances per minute per mL of saliva for the human experiment.
The degrees of freedom used in the statistics was 11 with a p-value of 4.575. The results show that at a pH of 6 for clams, the change in absorbance was the greatest at a pH of 6 (Figure 1). For humans at a pH of 7 the absorbance was the greatest (Figure 2). The results further show that the optimal pH was 6 for clams. It was found in another study that the optimal pH for clams was between 6.1 and 6.5 (Rosoiu et al.) For humans it makes sense that it does operate best around 7 as most of the freshwater in the world is generally around 7 which is considered neutral.
Discussion
The hypothesis was that there would be the most enzyme activity at a pH of 6 for the clams and the results show that. Although clams live in the intertidal zone of the marine ecosystem, the results showed that there was not a whole lot of enzyme activity at varying pH levels which matches with our hypothesis. However thinking about it logically, it brings up the question of why that is the case which could be used as a future research experiment. The error that comes from our data could possibly be influenced by there being contaminants on the spectrophotometer or it not being clear enough to read correctly such as if there was still dirt in the solution. It was also hypothesized that there would be a different pH for both clams and humans and our results do show that there was a higher absorbance at a pH of 7 for humans (Figure 2) and a higher absorbance at pH 6 for clams (Figure 1). In another experiment it was found that they believe that the optimal pH for Mya arenaria was between 6.1 and 6.5 (Rosoiu et al.) which matches up with our findings.
Works Cited
Lavine Tf. A study of the enzymatic and other properties of the crystalline style of clams;
evidence for the presence of a cellulase. Journal of Cellular and Comparative Physiology
1946 10;28(2):183-95
MacLean LA, MacNair NG, Davidson TJ, Johnson GG. Two-year comparison of spawning
patterns in soft-shell clams (Mya arenaria). National Shellfisheries Association; 1999.
Date revised – 2006-11-01; SuppNotes – Abstracts Only; Last updated – 2017-10-30.
Rosoiu N, Stoica S. Amylase activity in mya arenaria L.]. Cercet.Mar./Rech.Mar., (no.11),
203-213, (1978) 1978 03.
For this lab report we had to do a draft and then a final of our first scientific paper which this one is the final and this one is still far from perfect. One of the things that I think I did well on was the results section and the discussion section because the statistics made sense and my graphs which I could not load onto here really helped visualize what we found in our lab. The materials and methods section may seem the easiest, however it was the weakest section for me because so much more goes into it than just saying what you use and did in lab. Its fixed here but could definitely have better information.
