Mohd Sham Othman - Academia.edu (original) (raw)
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Papers by Mohd Sham Othman
Glutathione-S-Transferase (GST) and metallothionein are important biomarker endpoints in studying... more Glutathione-S-Transferase (GST) and metallothionein are important biomarker endpoints in studying the effect of Cd exposure. The purpose of this research was to study the correlation between hepatic GST and metallothionein with hepatic Cd in wild Fejervarya limnocharis exposed to environmental Cd. Results showed that frogs from contaminated sites had significantly higher hepatic metallothionein (3.58 mg/kg wet weight) and GST activity (0.259 lmol/min/mg total protein) than those from the reference site (2.36 mg/kg wet weight and 0.157 lmol/ min/mg total protein respectively). There was a significantly positive correlation between hepatic Cd and GST activity (r = 0.802, p = 0.009) but not between hepatic Cd and metallothionein (r = 0.548, p = 0.139). The results concluded that while frogs from the contaminated site had higher GST and metallothionein, only GST showed significant positive correlation with hepatic Cd levels, indicating that hepatic GST activity may be used as a biomarker endpoint.
Amphibians show a variety of reproductive modes and strategies. The cyclicity and continuity of r... more Amphibians show a variety of reproductive modes and strategies. The cyclicity and continuity of reproduction can often be predicted from the annual gonadosomatic index trends in a species specific manner. This research aims to document the female and male gonadosomatic index profiles and to ascertain the reproductive cyclicity or continuity of Fejervarya limnocharis (Anura: Ranidae) caught in Mae Sot, Tak Province, Thailand. Frogs were collected monthly between November 2007 and October 2009 in rice fields and their surrounding areas in the study site. For each frog, total weight and ovarian/testicular weight were measured to obtain the female and male gonadosomatic index. The number of female individuals with mature eggs (postvitellogenic eggs) was also counted. The results showed that female frogs had two main surges of increased GSI in March and September of 2008. Alternatively, male frogs showed a more gradual increase and decrease in gonadosomatic index, thus the index remaining high throughout the year. This study concluded that while F. limnocharis in this area is essentially a continuous breeder, it is more optimized for a cyclic reproduction mode with two breeding cycles during the rainy season.
Asian Herpetological Research, Aug 3, 2011
of the major determinants for timing of reproduction. Timing and intensity of rainfall play a maj... more of the major determinants for timing of reproduction. Timing and intensity of rainfall play a major role in determining when breeding should occur. Frogs in nonseasonal tropical environments often breed year round. These frogs often show a cyclical reproductive pattern. On the other hand, in seasonal tropical areas, breeding is usually timed to coincide with the wet season. Some species show explosive patterns while others exhibit a cyclical/continuous breeding mode throughout the wet season. The employment of continuous (acyclic) or discontinuous (cyclic) reproduction is developed accordance to egg incubation and the resulting hatchlings/ neonates. These stages are fragile, and, therefore, need hospitable condition, maximum survivorship, minimum physiological stress, few predators and maximum food.
Glutathione-S-Transferase (GST) and metallothionein are important biomarker endpoints in studying... more Glutathione-S-Transferase (GST) and metallothionein are important biomarker endpoints in studying the effect of Cd exposure. The purpose of this research was to study the correlation between hepatic GST and metallothionein with hepatic Cd in wild Fejervarya limnocharis exposed to environmental Cd. Results showed that frogs from contaminated sites had significantly higher hepatic metallothionein (3.58 mg/kg wet weight) and GST activity (0.259 lmol/min/mg total protein) than those from the reference site (2.36 mg/kg wet weight and 0.157 lmol/ min/mg total protein respectively). There was a significantly positive correlation between hepatic Cd and GST activity (r = 0.802, p = 0.009) but not between hepatic Cd and metallothionein (r = 0.548, p = 0.139). The results concluded that while frogs from the contaminated site had higher GST and metallothionein, only GST showed significant positive correlation with hepatic Cd levels, indicating that hepatic GST activity may be used as a biomarker endpoint.
Amphibians show a variety of reproductive modes and strategies. The cyclicity and continuity of r... more Amphibians show a variety of reproductive modes and strategies. The cyclicity and continuity of reproduction can often be predicted from the annual gonadosomatic index trends in a species specific manner. This research aims to document the female and male gonadosomatic index profiles and to ascertain the reproductive cyclicity or continuity of Fejervarya limnocharis (Anura: Ranidae) caught in Mae Sot, Tak Province, Thailand. Frogs were collected monthly between November 2007 and October 2009 in rice fields and their surrounding areas in the study site. For each frog, total weight and ovarian/testicular weight were measured to obtain the female and male gonadosomatic index. The number of female individuals with mature eggs (postvitellogenic eggs) was also counted. The results showed that female frogs had two main surges of increased GSI in March and September of 2008. Alternatively, male frogs showed a more gradual increase and decrease in gonadosomatic index, thus the index remaining high throughout the year. This study concluded that while F. limnocharis in this area is essentially a continuous breeder, it is more optimized for a cyclic reproduction mode with two breeding cycles during the rainy season.
Asian Herpetological Research, Aug 3, 2011
of the major determinants for timing of reproduction. Timing and intensity of rainfall play a maj... more of the major determinants for timing of reproduction. Timing and intensity of rainfall play a major role in determining when breeding should occur. Frogs in nonseasonal tropical environments often breed year round. These frogs often show a cyclical reproductive pattern. On the other hand, in seasonal tropical areas, breeding is usually timed to coincide with the wet season. Some species show explosive patterns while others exhibit a cyclical/continuous breeding mode throughout the wet season. The employment of continuous (acyclic) or discontinuous (cyclic) reproduction is developed accordance to egg incubation and the resulting hatchlings/ neonates. These stages are fragile, and, therefore, need hospitable condition, maximum survivorship, minimum physiological stress, few predators and maximum food.