[Studies On Phosphatase Activity In Some Parasitic Helminths]
In order to obtain some informations on the nature and relative activity of the phosphatases present in various helminths, biochemical studies have been made in thirteen kinds of worm parasites including the adults and larvae (Fasciola hepatica, Eurytrema pancreaticum, Paramphistomum sp., Taenia solium, Taenia pisiformis, Dipylidium caninum, Diphyllobothrium mansoni, Cysticercus cellulosae, Cysticercus fasciolaris and Sparganum). A comparison based on the analysis of pH-activity curves was made among these helminths. The worm materials were mostly obtained alive from an abattoir and removed from the organs or tissues of the animal hosts naturally infected. Sparganum and Cysticercus cellulosae, however, are collected from the subcutaneous tissue of the patients by surgical removal. The worms thoroughly washed were weighed and transferred with 0.1 M Tris buffer to a chilled glass grinder (Capacity; 15 ml) and homogenized in the cold. The homogenate was centrifuged at 5000 RPM for 30 minutes. The supernatant was pipetted off for determination of the phosphatase activity. Incubation mixtures consisted of 1 ml substrate, 1 ml buffer and 0.5ml extract. The buffers used were Tris (Hydroxymethyl) aminomethane and citric acid monohydrate and the substrate was paranitrophenyl phosphate (1 gm/25 ml). These mixtures were incubated at the temperature of 37 degrees C for 30 minutes in water bath. The absorbance or transferance of mixture was determined colorimetrically by "Spectronic 20 "spectrophotometer at 410 nm against a distilled water blank. The amount of phenol liberated was then calculated from a standard curve using phenol solutions. Controls consisted of unincubated mixtures. The results were deducted from this experiment. The phosphatase activity occurred over all parasitic helminths used in this experiment. In trematodes, pH-activity curves have demonstrated two peaks of phosphatase activity in Fasciola hepatica and Paramphistomum species. However the acid phosphatase activity was predominantly found and the alkaline phosphatase activity was found distinctly to be low in all three species. In Eurytrema pancreaticum, the pH-activity curves displayed two peaks in acid phosphatase activity, one at pH 5.0 and the other pH 9.0. In cestodes, both alkaline and acid phosphatase activity displayed the pH optima 5.0 and 9.0 to 10.0 in the adult tapeworms. However, major activity in the adults is due to the alkaline phosphtases. In contrast to the adults, Cysticercus and sparganum showed the higher activity in acid phosphatases which predominates in the larvae. In all cases of nematodes, the pH optimum for acid phosphatase was 4.0 to 6.0. A preponderance of acid phosphatase activity was shown in the extract of intestine of Ascaris lumbricoides. The aspect that phosphatases are correlated with phosphorylated passage of substances through the cuticle of helminths and may also be involved in carbohydrate metabolism is discussed.
Park
Chung Jai
CJ
Department of Parasitology and Institute of Endemic Diseases, College of Medicine, Seoul National University, Korea.
Seo
Byong Seol
BS