The Role of Actin and Microtubules in the Phagocytic Process

Tetrahymena is wide geographic range ciliated protozoa that are common in freshwaters. The protozoa can withstand a wide range of oxygen concentration, temperature and pH (Pham, et al. 13). The protozoa produce using asexual reproduction and can grow to huge populations over a short time under good conditions. The protozoa can also initiate sexual reproduction under specified environmental conditions such as starvation. The protozoa can ingest cell debris and microorganisms in relatively large amounts through the process of endocytosis. Phagocytosis is, therefore, the process when these protozoa ingest large materials through endocytosis. This process is an essential behaviour for the survival of the protozoa. The formation of phagosomes follows the ingestion of bacteria and the consequent vacuoles formation (Menta, Kirby and Corotto 37). The process has also been used as a defence mechanism to protect the body from infection in complex multicellular organisms. The process also aids in scavenging and elimination of damaged and dead cells from the body in higher organisms. Understanding the process of phagocytosis thus provides a foundation on which other processes occurring within a cell can be understood. This study presents a suitable model for exploration of eukaryotic cells in basic cell biology by observing the cell behaviour and morphology after the initial organism acquaintance. The study hence explores phagocytosis and the formation of vacuoles in macro-level cellular processes.  Phagocytosis quantification can be achieved by counting the vacuoles entering the cell over a given period.

Results

The measurements of vesicle formation over a specified period were done to evaluate the cytoskeletal inhibitor effects with and without the drug. The process involved cell incubation in India dye, washing, and consequent incubation in carmine ink. When viewed under a compound microscope, the vaculoes that contained India ink were spotted black while those of carmine appeared red, and their number steadily rose during the observation time and were used in the quantification of the phagocytosis process.  The experiment was conducted in the presence and absence of actin inhibitors to investigate their function in phagocytosis. The experimental observation was that the number of vaculoes formed in the presence of actin inhibitors was significantly lower than for the control EtOH test (Zackroff and Hufnagel 475). The decrease in the number of vaculoes was used to determine the role of actin in egestion.

The effect of microtubule on phagocytosis was studied with colchicine, an inhibitor from which the number of vaculoes was significantly affected by the inhibitor over time. The number of vaculoes significantly reduced in presence of colchicine due to carmine dye ingestion by phagocytosis (Stewart and Giannini 765). This was an indication that microtubules contributed to the phagocytic process. The conclusion is that though the role of microtubules involvement in exocytosis egestion is unclear, microtubules are relatively essential in the phagocytosis process.

Discussion

With an aim of understanding the process of phagocytosis, this experiment greatly helped the students by exposing them to them to research-level experiments. The published results on measurements of phagocytosis are very similar to the results of this experiment in that actin was found to significantly affect the number of vacuoles suggesting its involvement in phagocytosis. The experiment supported this data by showing a consequent decrease in the rate of the phagocytic process in actin disruptions allowing the student to delve deep into the literature. The experiment helped the student in contemplating the setup of the experimental design and the differences between the inhibitors. The influence of each inhibitor was examined and their relation to phagocytosis determined from the experimental data. The actin inhibitor was proven to prevent phagocytosis limiting the number of vaculoes for the egestion of indigestible materials. The student knowledge on cellular mechanism was therefore broadened by exploring these issues and the design of the experiments.

The use of colchicine also yielded interesting results. The process of phagocytosis was proven to be influenced by microtubules. The development of the oral groove is thus the most probable reason for the essence of the microtubules. The students hence were able to answer their research questions based on the experiment deduced from the process of phagocytosis and the vesicle movement and the development of their working models. The students were able to make derivations on the use of inhibitors and their influence on altered temperatures and pH conditions. The experiment introduced the students to the concepts of membrane dynamics. This enabled the students in making their interpretations of the experimental data at cellular levels. In conclusion, the students were able to learn about the cellular process of phagocytosis and the behavior of the protozoa under the conditions in the experimental design. As the student reads the literature on the process of phagocytosis, it hence presents them the opportunity to develop further research questions on the function of inhibitors and the molecular mechanisms of phagocytosis. The experiment thus presents the student with areas of future work while providing for them a framework from which the design of an experiment is crucial to achieving the results. In cellular processes, among other areas that the students can advance their research in the process of phagocytosis is the test on effects of lysosomal fusion on inhibiting the phagocytic process.

Works Cited

Zackroff, Robert V., and Linda A. Hufnagel. "Induction of anti-actin drug resistance in Tetrahymena." The Journal of eukaryotic microbiology 49.6 (2002): 475-477.

Menta, Blaise W., Ashley E. Kirby, and Frank S. Corotto. "AN EXAMINATION OF SELECTIVE FEEDING AND MOLECULAR RECOGNITION IN THE CILIATE, TETRAHYMENA PYRIFORMIS Ehrenberg, 1830." Georgia Journal of Science 75.1 (2017): 37.

Pham, Cindy, et al. "The Effect of Temperature on Food Vacuole Formation in Tetrahymena thermophila." The Expedition 7 (2018).

Stewart, Chris, and John Giannini. "Analyzing Tetrahymena Movement with an Inexpensive & Engaging Inquiry Lab." The American Biology Teacher 78.9 (2016): 764-771.