Since Faure-Fermiet's report(1913) concerning the respiration of ascaris eggs, Brown(1928), Huff(1936), Jaskoski(1952), Passey(1955) and Yanagizawa(1955) presented their respective reports on the oxygen consumption of ascaris eggs during the growth.
Kawazoe(1960) ascertained that the ascaris eggs had a different oxygen consumption in each developmental stage. According to his report, the double cell stage consumed oxygen less than in the unicell stage, but it was increased again toward the multicell stage and reaching to maximum during the larva formation.
Brown(1928) indicated that ascaris eggs suspended their growth under the anaerobic condition, but resumed their growth when oxygen was supplied again. Brown verified that ascaris eggs remained alive approximately for six weeks under oxygen free condition. Huff(1963) claimed that the decorticated ascaris eggs increased oxygen consumption, but his affirmation was failed to be recognized by other investigators.
Numerous reports have been published concerning the ovicidal agents for the destruction of ascaris eggs.
Recently Kozai (1960) reported that sodium nitrite showed remarkable ovicial action on the ascaris eggs in feces-urine mixture, especially at the acid condition.
The The present study was designed to know whether sodium nitrite had inhibitory action on the respiration of ascaris eggs and what part of the enzymatic action of krebs cycle it did effect upon.
Meterials and methods
Immature stage and matured stage of ascaris eggs were used throughout the study. The substrate media were the feces-urine(1:4), fecal solution(feces: water=1:4) and urine. The pH of the media was regulated with N/10 HCI or calcium superphosphate.
Sodium nitrite was added to the medium at the ratio of 1:1,000.
After the certain period of experiment, oxygen consumption rate of the eggs were calculated by Warburg manometer and then biological examination was continued(by recultivation or animal inoculation etc.) in order to confirm the survivability of the eggs. The inhibitory action on succinic dehydrogenease was also examined with the rat liver tissue.
NO^^2 gas was produced from sodium nitrite in acid medium, and the gas which was released from 1% sodium nitrite solution destroyed all ascaris eggs within 8 hours and less effects were found in 0.5% and 0.1% solution. In the medium of pH 7.0, the
chemical did not show any gas production and no significant influence on oxygen uptake, while in pH 4.0-6.- showed remarkable difference on oxygen consumption between sodium nitrite treated group (0.54-1.00x10**-6 μl/hr/egg) and non-treated group (5.57-12.07x10^^-6 μl/hr/egg).
A few of the ascaris eggs, which were survived even after the sodium nitrite treatment, developed to matured stage but it was found that they lost their infectivity through animal experiment.
Sodium nitrite also showed inhibitory action on the liver slice respiration, but there was nomanifestation to destroy the succinic dehydrogenase. This indicates that sodium nitrite affects a certain enzyme in Krebs cycle other than succinic
Summary and conclusion
The effects of sodium nitrite upon the oxygen consumption of Ascaris lumbricoides was examined manometrically with Warburg apparatus.
1) The fresh stage of ascaris eggs, which were treated in feces-urine medium (pH 4.0) containing 0.1% of sodium nitrite at 25℃ for 72 hours consumed oxygen 0.54-1.00x10^^-6 μl/hr/egg which amounted to one-tenth of control.
2) The sodium nitrite treated eggs consumed less oxygen than the control and it was proved by cultivation that 92-100% of the treated eggs were destroyed.
3) The treated eggs continued the same level of low rate of oxygen consumption while the control group showed five times of oxygen consumption after 3 weeks of cultivation comparing with the initial value.
4) NO^^2 gas which was generated from the 2% HCI or 4% calcium superphosphate solution containing sodium nitrite showed direct action to ascaris eggs and led them to destruction. However in the medium, which the NO^^2 gas were all evaporated, the ascaris eggs were all alive.
5) The infective stage of ascaris eggs showed the same response to sodium nitrite as were in fresh stage of ascaris eggs.
6) The sodium nitrite did not affect the succinic dehydrogenase. It is probable that chemical might have an inhibitory action upon other enzymes in Krebs cycle.
Through above results, it is concluded that sodium nitrite inhibits the oxygen consumption of the eggs of Ascaris lumbricoides and lead them to destroy, affecting the enzyme in Krebs cycle other than succinic dehydrogenase.