Shinya Matsumoto et al. (2003) International Worm Meeting "Effect of endocrine disrupters on reproduction of C. elegans."

Yasuki Matsumura, Tohomiko Mori, Shinya Matsumoto

[International Worm Meeting, 2003]

Certain chemical compounds in the environments are reported to mimic the functions of endocrine hormones of many organisms and because of their potential function to disrupt the hormone balance in organisms, they are often termed endocrine disrupters. Some phthalates used as plastic softeners (such as butylbenzylphthalate and dibutylphthalate), alkylphenols used in polymers (such as nonylphenol, p-octylphenol, Bisphenol A), synthetic sex hormones (such as diethylstilbestrol(DES) and ethynylestradiol) and heavy metal-containing compounds (such as tributyltin) are among those suspected to be endocrine disrupters. Among those which are reported to be the effect of endocrine disrupters, its influence on sperm formation and/or production in mammals has been attracting the attention. While the production of oocytes in C.elegans hermaphrodite continues throughout its adulthood, that of sperm takes place only during the L4 stage and the number of produced sperm is fairly constant (about 300 sperms), which means the number of the progeny of a self-mating hermaphrodite is limited by the number of the sperms produced. Therefore, the potential effect of endocrine disrupters on the sperm formation could be assessed by counting the number of progeny of a hermaphrodite. We investigated the effect of these compounds on the reproduction properties of C.elegans using this methods. Two mixture was prepared; DES, Bisphenol A, nonylphenol, octylphenol, dibutyl phthalate, butylbenzyl phthalate and styrene monomer as A group and B group for the mixture of heavy metals containing Cu, Ni, Co, Mn, Zn, Pb and Sn. These mixture were added separately or together at various concentration to NGM plate and the number of progeny from a hermaphrodite raised on it was counted. When worms were raised on the plate containing A group or B group or A+B group, significant decrease in the number of progeny was not observed at any concentration. On the other hand, when they are raised on a plate containing both group at very low concentration (1-10 ppt), the number of progeny appeared to decrease to 60-70 % of that of control. We are seeking which of the components in the mixture is responsible for the effect together.

Tomoko Aso et al. (2004) East Asia Worm Meeting "The effect of oxidized fatty acid on C.elegans antioxidant status measured by electron spin resonance (ESR)."

Shinya Matsumoto, Akiko Souma, Tomoko Aso, Yasuki Matsumura, Rie Kimura, Tomohiko Mori

[East Asia Worm Meeting, 2004]

Unsaturated fatty acids are easily oxidized because of the oxygen susceptibility of unsaturated bonds in the molecules. Many studies have shown that oxidized fatty acids have variety of adverse effects on organisms as oxidative stress, e.g., cell membrane oxidation and DNA damage. It is known that oxidative stress induces aging and shortens lifespan, but the mechanisms are remained largely unanswered. We asked whether the fed oxidized fatty acid have changed redox status in C. elegans by instrumental analysis.We used electron spin resonance (ESR), which is a useful analysis for free radical studies. ESR, which is a popular and traditional instrument in the antioxidation analysis, can detect free radical and gives specific spectrum of the radical. When nitroxide radicals such as Tempol are administered to an animal, they are reduced by hosts' redox systems and lose ESR signals. So far, this measurement has not been applied on C.elegans . We examined changes in the ESR signal of Tempol administered to C.elegans and measured of the reduced rate of Tempol as intensity of the reduction activity of worms. We fed wild type worms with hydroperoxides and the oxidized fatty acids. Then, we examined the effects of the oxidants on redox status of C.elegans . In this analysis, we observed reduction of Tempol in wild type. In C.elegans which was fed bacteria together with oxidized fatty acids and hydroperoxides, enhanced reduction activity had been observed in comparison with wild type. These results showed that it is possible to measure the reduction activity of C.elegans with ESR and suggested that the antioxidant activity of C.elegans fed with the oxidants was enhanced because of the oxidative stress

Shinya Matsumoto et al. (2005) International Worm Meeting "Effect of oxidized fatty acids on C. elegans redox status."

Tomoko Aso, Rie Kimura, Shinya Matsumoto, Tomohiko Mori, Akiko Soma, Yasuki Matsumura

[International Worm Meeting, 2005]

Oxidized fatty acids, when orally administered, cause toxic effect to organism. Although the adverse effect of oxidative stress upon cell and cellular components such as plasma membrane, protein and DNA, has been intensively studied, the exact molecular mechanism concerning toxic effect of oral administration of oxidized fatty acids is not fully understood. To evaluate the effect of oxidized fatty acids from the stand point of nutrition and bio-safety, we fed C.elegans with oxidized fatty acids and observed the effect of the oxidized fatty acids upon fertility, life span and the expression of genes which are implicated on antioxidative stress. Oxidized oleic (18:1), linoleic (18:2), arachidonic (20:4), icosapentaenoic (20:5) and docosahexaenoic acid (22:6) were incorporated into debris of OP50 membrane and seeded with live OP50 on NGM plate. N2 eggs were laid on the plate and the hatched worms were exposed to the oxidized fatty acids throughout their development. The number of progeny derived from the oxidized fatty acids-fed worms showed little change compared with that of normal OP50-fed worms, indicating oxidized fatty acids had no effect of the fertility of worms. Oxidized fatty acids induced increased death around 7-10 days after hatch, which was not observed in OP50-fed worms. The average life span (50% death length) and the maximum life span were less influenced by the oxidized fatty acids. This indicates that oxidized fatty acid susceptibility increased temporarily or stage-specifically during worm life time. The expression of SOD and catalase have shown to be enhanced during this stage. We then asked whether the fed oxidized fatty acid have changed redox status in C. elegans by electron spin resonance (ESR). ESR detect free radical compound based on the existence of unpaired electron in the molecule and gives specific spectrum of the radical. When stable nitroxide radicals such as Tempol are administered to an animal, they are reduced either by hosts' redox systems or endogenous free radicals and consequently the Tempol signal intensity is weakened. Therefore, by comparing the decrease rate of Tempol signal intensity, the endogenous redox status of the animal can be evaluated. We fed N2 worms with hydroperoxides and the oxidized fatty acids. Tempol was added to the worms and the effects of the oxidants on redox status of the worms was examined by ESR. In worms which were fed bacteria together with oxidized fatty acids and hydroperoxides, enhanced reduction activity of Tempol had been observed in comparison with worms fed without oxidants. These results may indicate the oxidized fatty acids may induce oxidative stress on worm by increasing the endogenous free radicals.

Shinya Matsumoto et al. (2004) East Asia Worm Meeting "Effect of oxidized fatty acids on viability of C.elegans."

Akiko Souma, Rie Kimura, Yasuki Matsumura, Tomohiko Mori, Tomoko Aso, Shinya Matsumoto

[East Asia Worm Meeting, 2004]

Oxidized fatty acids, when orally administered, cause toxic effect to organism, in the worst case, to the death. Although the adverse effect of oxidative stress upon cell or cellular components, such as plasma membrane, protein and DNA, has been intensively studied, the exact molecular mechanism concerning toxic effect of oral administration of oxidized fatty acids is not fully understood. To evaluate the effect of oxidized fatty acids from the stand point of nutrition and bio-safety, we fed C.elegans with oxidized fatty acids and observed the effect of the oxidized fatty acids upon fertility, life span and the expression of genes which are implicated on antioxidative stress.Oxidized oleic (18:1), linoleic (18:2), arachidonic (20:4), icosapentaenoic (20:5) and docosahexaenoic acid (22:6) were incorporated into debris of OP50 membrane and seeded with live OP50 on NGM plate. N2 eggs were laid on the plate and the hatched worms were exposed to the oxidized fatty acids throughout their life-time. The number of progeny derived from the oxidized fatty acids-fed worms showed little change compared to those of normal OP50-fed worms, indicating oxidized fatty acids had no effect of the fertility of worms. Oxidized fatty acids induced increased death around 7-10 days after hatch, which was not observed in OP50-fed worms. The average life span (50% death length) and the maximum life span were less influenced by the oxidized fatty acids. This indicates that oxidized fatty acid susceptibility increased temporarily or stage-specifically during worm life time. The expression of SOD and catalase have shown to be enhanced during this stage.