Physarum Lab
Calcium, Magnesium, and Cytoplasmic Streaming in Physarum Polycephalum
Eugenia Rita Lee
Dr. Bonner
BIO 111
Introduction:
Physarum polycephalum is a type of slime mold of the myxogastria class that prefers warm and damp conditions. It can go through three forms, plasmodium, sclerotium, and sporangia. The plasmodium is the primary active state, where P. polycephalum consists of protoplasmic veins and multiple nuclei. During this stage, the slime mold surrounds its’ food and secretes enzymes to break the particles down into nutrients P. polycephalum can absorb. P. polycephalum moves by way of cytoplasmic streaming, which is directed flow of cytosol (the liquid component of the cytoplasm) and organelles around large fungal and plant cells through the use of actin. Cytoplasmic streaming in this particular slime mold is labeled shuttle streaming, because the fungus reverses the direction of the streaming every 1.5 to 3 minutes. Calcium is shown to increase the growth of P. polycephalum in the first 48 hours, then impede the growth due to calcium binding to the myosin, which may serve as a signal to slow and increase the rate of cytoplasmic streaming (Farkas et al. 2003; Zhang et al. 2012; Ridgway and Durham 1976; Kuroda & Kuroda 1982; Terry et al. 2009;).
Calcium and magnesium are both from the same chemical group and have similar chemical and physical properties. Our hypothesis was that that the rate of cytoplasmic streaming in a calcium or magnesium environment will be significantly different than the rate of streaming in plain 2% agar and that calcium and magnesium will have an equal effect on cytoplasmic streaming in Physarum polycephalum because of their similar chemical properties.
Methods:
To set up P. polycephalum samples, 15 plates of agar were set up to culture the mold. After mixing 2M solutions of calcium and magnesium, agar was measured and mixed into the solutions and 5 plates of calcium solution, 5 plates of magnesium, and 5
Eugenia Rita Lee
Dr. Bonner
BIO 111
Introduction:
Physarum polycephalum is a type of slime mold of the myxogastria class that prefers warm and damp conditions. It can go through three forms, plasmodium, sclerotium, and sporangia. The plasmodium is the primary active state, where P. polycephalum consists of protoplasmic veins and multiple nuclei. During this stage, the slime mold surrounds its’ food and secretes enzymes to break the particles down into nutrients P. polycephalum can absorb. P. polycephalum moves by way of cytoplasmic streaming, which is directed flow of cytosol (the liquid component of the cytoplasm) and organelles around large fungal and plant cells through the use of actin. Cytoplasmic streaming in this particular slime mold is labeled shuttle streaming, because the fungus reverses the direction of the streaming every 1.5 to 3 minutes. Calcium is shown to increase the growth of P. polycephalum in the first 48 hours, then impede the growth due to calcium binding to the myosin, which may serve as a signal to slow and increase the rate of cytoplasmic streaming (Farkas et al. 2003; Zhang et al. 2012; Ridgway and Durham 1976; Kuroda & Kuroda 1982; Terry et al. 2009;).
Calcium and magnesium are both from the same chemical group and have similar chemical and physical properties. Our hypothesis was that that the rate of cytoplasmic streaming in a calcium or magnesium environment will be significantly different than the rate of streaming in plain 2% agar and that calcium and magnesium will have an equal effect on cytoplasmic streaming in Physarum polycephalum because of their similar chemical properties.
Methods:
To set up P. polycephalum samples, 15 plates of agar were set up to culture the mold. After mixing 2M solutions of calcium and magnesium, agar was measured and mixed into the solutions and 5 plates of calcium solution, 5 plates of magnesium, and 5
References: Farkas L, Málnási-Csizmadia A, Nakamura A, Kohama K, Nyitray L. 2003. Localization and characterization of the inhibitory Ca2+-binding site of Physarum polycephalum myosin II. Journal of Biological Chemistry 278:27399-27405. Kuroda R, Kuroda H. 1982. Relation of cytoplasmic calcium to contractility in Physarum polycephalum. Journal of Cell Science 53:37-48. Matthews LM Jr. 1977. Ca++ regulation in caffeine-derived microplasmodia of Physarum polycephalum. Journal of Cell Biology 72:502-505. Ridgway EB, Durham AC. 1976. Oscillations of calcium ion concentrations in Physarum polycephalum. Journal of Cell Biology 69:223-226. Terry LC, Stefanski HM, Eisemann BA. 2009. Effects of calcium on growth of Physarum polycephalum. BIOS 85:159-163.