Effect of pH on vinegar eel (Turbatrix aceti)

Sophia Iribarren

Department of Biological Sciences

Saddleback College

Mission Viejo, California 92692

Abstract

Turbatrix aceti tolerates a pH range of 1.6 to 11 for various periods of time. The objective of this experiment was to test the forward velocity as the pH on the external surrounding of the T. aceti is changed. The purpose was to understand the movement of the muscles and effect on locomotion at different pH levels. T.aceti nematodes were placed in six 30 ml beakers with of solutions at pH of two, four, six, eight, and ten. Ten vinegar eels were timed with a stop watch and the distance traveled was measured through the microscope for each solution. Results indicate that the average forward velocity of T.aceti afteracclimated in the six different pH solutions was significantly different as the pH in solution was increased or decreased.

Introduction

The free living nematode, the vinegar eel (Turbatrix aceti)has been fascinating to many naturalists. They are a few millimeters in length and are barely visible to the naked eye.In 1765 Linnaeus included the Vinegar eel in his Systema Naturae and named it Chaos redivivum(The British Medical journal, 1928). During the 18th century there was a controversy on the name given by Linnaeus; he had given the same name to the worms found in vinegar and the worms found in book binder’s paste. This issue remained unresolved until DeMann published a paper on vinegar eels in 1910. The vinegar eel received its new name Turbatrix aceti (MacGowan, 1982).

T. aceti tolerates a pH range of 1.6 to 11 for various periods of time and grows in a pH ranging from 3.5 to 9 (Goodey, 1963). The eelworm can be recognized by its lack of circular muscles and by its rapid lateral lashing movement (Galen, 1971). They move by muscle contraction producing wave like functions and undulations (Gray, 1939).Vinegar eels are sinusoidal swimmers (Drewes et. al, 2002). Nematodes can sense variations in their external surroundings and respond to them. Muscles of the body wall are controlled by inhibitory and excitatory neuromuscular synapses (Alexander, 2002).

The objective of this experiment was to test the forward velocity as the pH on the external surrounding of the T. aceti is changed. The purpose was to understand the movement of the muscles and effect on locomotion at different pH levels. The forward velocity was expected to be higher at a low pH and lower at higher pH levels.

Materials and Methods

Vinegar eels used in this experiment were obtained from Wards Biological Society in San Luis Obispo. Randomly chosenT. aceti nematodes were placed in six 30 ml beakers with of solutions at pH oftwo, four, six, eight, and ten. The solutions were made using 1M NaOH, 0.01M NaOH, 1M HCL, and 0.01 M HCL. A solution with a pH of three was used as the control group since the optimum pH is three( Ells et al. 1961). The vinegar eels were allowed to acclimate to the different pH levels for 24 hours at room temperature.

After the acclimation period a sample of vinegar eels was placed under the E2000 microscope at low power (4x). Ten vinegar eels were timed with a stop watch and the distance traveled was measured through the microscope for each solution. The head of the vinegar eel was used as the start and fish reference point. By determining the traveled distance and the time the forward velocity was determined.

The forward velocity (VF) of the vinegar eel was measured using this formula:

This same procedure was repeated with all of the six solutions.

Results

Sixty vinegar eels were used in this experiment. Their ability to tolerate abrupt pH changes from a pH of two to ten was confirmed.Results indicate that the average forward velocity of T.aceti afteracclimated in the six different pH solutions was significantly different (ANOVA, p= 0.000) as the pH in solution was increased or decreased (Figure 1).


Figure 1.Average forward velocity (mm/s) of T.aceti after acclimated in different pH. ANOVA showed a significant difference (p=0.001).

The control group demonstrated a higher VF on average than the experimental groups. As the pH of the solution was increased or decreased, the average VF of T.aceti lowered over the measured period.The mean VF for pH 2 was 10.7mm./s-1, forpH 3was 16.8mm./s-1, for pH 4 was 11.0mm./s-1, pH 6 was 9.24mm./s-1, pH 8 was 9.23mm./s-1, and for pH 10 was 4.84mm./s-1.

A Bonferroni correction was run and the results showed significance between pH: 2 and 3, 2 and 10, 3 and 4, 3and 6, 3 and 8, 3 and 10, and 4 and 10.

Discussion

T. aceti locomotion was affected by the increase or the decrease of the pH. The effect on locomotion was shown by the decrease of the VF of the vinegar eel. They did not show ability maintain the same velocity as they were placed in the six different solutions.

There may be some reasons why the VFofT. aceti was affected. The naturally functioning enzymes involved in locomotion do not function well with changes in pH.In nematodes locomotion depends on transmission forces generated by muscular contractions (Gaugler, 2004). Enzymes have an optimum pH at which their activity is maximal, as the pH increases or decreases the enzymatic activity can change leading to a change in other metabolic functions (Lehringer, 2005).

Further studies on pH acclimation could be done since a gradual acclimation was not performed this could have affected the VF results. Further research is required to determine if the VF in t. aceti becomes insignificant with gradual acclimation to the different solutions if that were trueother studies could be done to understand how the enzymatic pathways of T. aceti changes with the change in pH.

Bibliography

Goodey, T. (1963). Soil and Freshwater Nematodes. John Wiley & Sons: 147-173.

Donald F. Galen (1971). Culturing and Using the Vinegar Eel.The American Biology Teacher. Vol 33, No. 4: 237-238

Gray, J. (1939). The kinetics of locomotion of Nereis diversicolor. Studies in animal locomotion. Exp. Biol. 16: 9-17.

Drewes, C. and M. Oehler (2004). Invertabrate ‘LocOlympics’:Investiagtion and inquiry into invertebrate locomotion and biomechanics. Conference of the Association for Biology Laboratory Education pp: 235-253.

Alexander, R. (2002). “Locomotion.” The Biology of Nematodes: 345-352.

The Vinegar Eel-Worm (1928).The British Medical Journal, Vol. 1, No. 3519 pp. 1038-1039

J.B. MacGowan. The vinegar eel worm. Agriculturar and Consumer Services, Nematology Circular.

H.A. Ells, C.P. Read (1961). Physiology of the vinegar eel, turbatrix aceti I.Observation on respiratory metabolism. Biology, Bull 120:326-336

Randy Gaugler, Anwar L. Bilg (1956). Nematode behaviour. Oxfordshire, United Kingdom.CAB international. 82p.

Albert L. Lehninger, David Lee Nelson, Michael M. Cox (2005). Principles of Biochemestry.Basingstoke, England.Sara Tenney.1089p.