Cytotoxicity of inorganic mercury to the liver of two species,Anabas tesludineus and Sprague Dawley male rat was evaluated.Distribution kinetics of this metal in the different hepatic subcellular fractions were follow...Cytotoxicity of inorganic mercury to the liver of two species,Anabas tesludineus and Sprague Dawley male rat was evaluated.Distribution kinetics of this metal in the different hepatic subcellular fractions were followed for 48 h after a single injection of[^(203)Hg]mercuric nitrate at a dose of 4mg/kg b.w.Interaction of this metal with protein,DNA and RNA was also studied.In rat,nuclear and lysosomal fractions showed a significant increase in the protein content,while in fish,the amount of protein increased in all fractions except microsome.Comparatively more mercury was bound to protein in fish during the later phase of treatment.Retention of mercury in nuclear DNA of rat gradually declined from 15 min to 48 h of treatment,while,mitochondria!DNA binding to mercury increased from 15 min to 2 h of post injection and then declined in the later phase of the experiment.Such a biphasic binding pattern of mercury was shown by both the nuclear and mitochondrial DNA of the fish.The nuclear RNA of rat and mitochondrial and cytosolic RNA of both test species also showed a biphasic pattern of mercury binding,however,with a higher rate of binding in fish at the later phase of the experiment.The present study thus highlights that(a)mercury follows a definite distribution pattern in the subcellular fractions of the liver in both animal species,(b)cytosol is the major site of mercury accumulation.展开更多
A regional profile of AChE activity was noted in the Indian termite queen Odontotermes redemanni with the head recording the higher and body the lower range of activity.The enzyme characteristics such as substrate and...A regional profile of AChE activity was noted in the Indian termite queen Odontotermes redemanni with the head recording the higher and body the lower range of activity.The enzyme characteristics such as substrate and temperature optima were more or less similar while pH requirement for optimum AChE activity varied from 7.0 to 7.6 In vitro inhibition of head and body AChE was studied using pure and commercial anticholinesterase compounds.Interestingly,the commercial formulations like Metacid-50 and Carbaryl are potent enough at 1×10^(-8)M to produce 50%in vitro inhibition of AChE of head and body regions within 15 min of preincubation.A 20 min of preincubation(t0.5)was necessary to record 50%in vitro inhibition of AChE with known and pure anticholinesterase compounds such as DFP(3.5×10^(-10)M)and physostigmine(3.6×10^(-10)M).It is surmised that(a)the response of the head and body AChE to the commercial formulations of the insecticides may be used as a reliable and sensitive bioindicator of pesticidal contamination of the terrestrial environment and(b)termite control may be successfully done with the application of organophosphate or carbamate compounds.展开更多
The distribution of mercury,an environmentally important toxicant,has been evaluated in a time dependent manner in different tissues of white rat and a freshwater teleost,Anabas testudineus.Sampling was performed at 1...The distribution of mercury,an environmentally important toxicant,has been evaluated in a time dependent manner in different tissues of white rat and a freshwater teleost,Anabas testudineus.Sampling was performed at 15 min,2,6 and 48 h post injection(im)of 203Hg mercuric nitrate.Radioactivity of the 5%tissue homogenate,serum and bile was measured in a Gamma Counter.The rate of 203Hg accumulation is higher in fish immediately after administration which,however,is more or less of equal rate in the later period of observation in both the experimental animals.Partitioning of 203Hg occurs in a species specific manner with higher levels recorded in the brain and gonad of white rat.Spleen,liver and kidney,however,are the major tissues to accumulate mercury in both the species.The present study highlights that kidney is the target site of mercury retention with a higher kidney/liver ratio of mercury.展开更多
基金S.Bose is grateful to the Department of Atomic Energy,Bombay for a Dr.K.S Krishnan Fellowship P.Ghosh,S.Ghosh and Choudhury gratefully acknowledge CSIR+1 种基金New Delhi for Senim-Research Fellowships and a Pool OfficcrshipS.Bhattacharya is thankful to Visva-Bharati University for financial assistance.
文摘Cytotoxicity of inorganic mercury to the liver of two species,Anabas tesludineus and Sprague Dawley male rat was evaluated.Distribution kinetics of this metal in the different hepatic subcellular fractions were followed for 48 h after a single injection of[^(203)Hg]mercuric nitrate at a dose of 4mg/kg b.w.Interaction of this metal with protein,DNA and RNA was also studied.In rat,nuclear and lysosomal fractions showed a significant increase in the protein content,while in fish,the amount of protein increased in all fractions except microsome.Comparatively more mercury was bound to protein in fish during the later phase of treatment.Retention of mercury in nuclear DNA of rat gradually declined from 15 min to 48 h of treatment,while,mitochondria!DNA binding to mercury increased from 15 min to 2 h of post injection and then declined in the later phase of the experiment.Such a biphasic binding pattern of mercury was shown by both the nuclear and mitochondrial DNA of the fish.The nuclear RNA of rat and mitochondrial and cytosolic RNA of both test species also showed a biphasic pattern of mercury binding,however,with a higher rate of binding in fish at the later phase of the experiment.The present study thus highlights that(a)mercury follows a definite distribution pattern in the subcellular fractions of the liver in both animal species,(b)cytosol is the major site of mercury accumulation.
基金PG and SG are grateful to the Council of Scientific and Industrial Research,New DelhiPH to the Department of Science and Technology,New Delhi for financial support.
文摘A regional profile of AChE activity was noted in the Indian termite queen Odontotermes redemanni with the head recording the higher and body the lower range of activity.The enzyme characteristics such as substrate and temperature optima were more or less similar while pH requirement for optimum AChE activity varied from 7.0 to 7.6 In vitro inhibition of head and body AChE was studied using pure and commercial anticholinesterase compounds.Interestingly,the commercial formulations like Metacid-50 and Carbaryl are potent enough at 1×10^(-8)M to produce 50%in vitro inhibition of AChE of head and body regions within 15 min of preincubation.A 20 min of preincubation(t0.5)was necessary to record 50%in vitro inhibition of AChE with known and pure anticholinesterase compounds such as DFP(3.5×10^(-10)M)and physostigmine(3.6×10^(-10)M).It is surmised that(a)the response of the head and body AChE to the commercial formulations of the insecticides may be used as a reliable and sensitive bioindicator of pesticidal contamination of the terrestrial environment and(b)termite control may be successfully done with the application of organophosphate or carbamate compounds.
文摘The distribution of mercury,an environmentally important toxicant,has been evaluated in a time dependent manner in different tissues of white rat and a freshwater teleost,Anabas testudineus.Sampling was performed at 15 min,2,6 and 48 h post injection(im)of 203Hg mercuric nitrate.Radioactivity of the 5%tissue homogenate,serum and bile was measured in a Gamma Counter.The rate of 203Hg accumulation is higher in fish immediately after administration which,however,is more or less of equal rate in the later period of observation in both the experimental animals.Partitioning of 203Hg occurs in a species specific manner with higher levels recorded in the brain and gonad of white rat.Spleen,liver and kidney,however,are the major tissues to accumulate mercury in both the species.The present study highlights that kidney is the target site of mercury retention with a higher kidney/liver ratio of mercury.
