Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential p...Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential protective effects of Spirulina platensis(SP)against the effects of EtBr toxicity in the Nile tilapia(Oreochromis niloticus)fry.Fry were divided to five groups,viz.,a control and four treatment groups of low-dose EtBr(10μg/L),low-dose EtBr with SP(10μg/L EtBr+200 mg/L SP),high-dose EtBr(100μg/L),and high-dose EtBr with SP(100μg/L EtBr+200 mg/L SP);the exposure period was 2 weeks.Low and high doses of EtBr induced alterations in some hematological,biochemical,and histopathological parameters.Necrotic hepatocytes,degenerated area,vacuolated hepatocytes,pyknotic nuclei,constricted and dilated blood sinusoids,and infiltration of inflammatory cells were observed.Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP,but it was increased in groups exposed to high doses of EtBr and EtBr with SP,compared with the control group.After feeding with SP,most histological and histochemical parameters restored to normal values.Therefore,SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.展开更多
Under different conditions, oligonucleotides can form several alternative DNA structures such as duplex, triplex and quadruplex. All these structures can interact with ethidium bromide (EB) and make its fluorescence i...Under different conditions, oligonucleotides can form several alternative DNA structures such as duplex, triplex and quadruplex. All these structures can interact with ethidium bromide (EB) and make its fluorescence intensity change. The fluorescence spectra and other related parameters provided by static fluorescence techniques showed that the interaction mechanisms between EB and these structures were not always the same. Among them, B type duplex and triplex DNA adopt an intercalative mode when binding to the EB, which has a relatively high efficiency of energy transfer and the fluorescence of EB cannot be quenched easily. While for the parallel duplex DNA, the interaction mode is an outside binding in which energy transfer can hardly happen and its fluorescence intensity as well as Stern-Volmer constant is almost the same to the free EB. For the quadruplex, the binding mechanism to EB is more complex. Results from the energy transfer and quenching studies indicate that the two interaction modes noted above probably coexist at the same time.展开更多
The preparations,the formation conditions and stabilities of duplex dA_(10)·dT_(10)and triplax dA_(10)·2dT_(10),and the interactions of ethidium bromide with them in an appropriate buffer are reported.Flu- o...The preparations,the formation conditions and stabilities of duplex dA_(10)·dT_(10)and triplax dA_(10)·2dT_(10),and the interactions of ethidium bromide with them in an appropriate buffer are reported.Flu- orescence spectra show that ethidium can be used as a useful fluorescence probe to detect triplex formation, and its fluorescence is significantly increased by either the duplex or triplex,but less in the case of the triplex.Thermal denaturation profiles demonstrate that the stability of the triplex is enhanced by ethidium. Fluorescence energy transfer studies suggest the existence of similar energy transfer from the triplex or du- plex to the bound ethidium but the presence of the triplex results in substantially smaller energy transfer than that of the duplex does.Furthermore,fluorescence quenching using the anionic quencher[Fe(CN)_6]^(4-)can- not decrease the fluorescence intensities of triplex/ethidium complex.These results demonstrate that ethidi- um has significantly binding affinity with the triplex,and interacts with it via intercalative mechanism,thus increases its stability.展开更多
The luminous intensity of dark variant (S1) separated from photobacterium phosph oreum (A2) was 1/10 000 less than that of wild type. Ethidium bromide (EB) (0.6 mg/L), Mytomycin C (MC, 0.05 mg/L), 2 amino fluorene ...The luminous intensity of dark variant (S1) separated from photobacterium phosph oreum (A2) was 1/10 000 less than that of wild type. Ethidium bromide (EB) (0.6 mg/L), Mytomycin C (MC, 0.05 mg/L), 2 amino fluorene (2 AF, 1.0 mg/L) all cou ld strongly induce reversion mutation for S1 within 24 h and increase reversion ratio significantly. The results of experiments indicated that these revertants had stable genetic characteristic and the mutation may take place at gene levels . The mutagenesis to S1 caused by EB, MC and 2 AF was detected and it may be us ed as a new rapid, simple and sensitive method for gene toxicant monitoring.展开更多
Taking advantage of the effects on DNA secondary structure of two DNA-intercalators,ethidium bromide and chloroquine,we used each of them to treat nuclei from both mature erythrocytes and reticulocytes of chicken,as a...Taking advantage of the effects on DNA secondary structure of two DNA-intercalators,ethidium bromide and chloroquine,we used each of them to treat nuclei from both mature erythrocytes and reticulocytes of chicken,as an alternative approach to study the relationships between DNA secondary structure,nuclear proteins and chromatin structure.We presented results of differential extraction of nuclear proteins from nuclei with DNA-intercalators,as well as preliminary characterization of these proteins.A 45kd protein is the major component in fractions extracted by both intercalators from nuclei from either mature erythrocytes or reticulocytes and seems to be a DNA-binding protein.Furthermore,from current concepts of functional aspects of DNA conformation and structural heterogeneity in chromatin and nuclear proteins,we have discussed both the significance of our results as well as technical aspects of this approach.展开更多
Ethidium bromide is a fluorescent tag and is used in biomedical applications.It is a potent mutagen because of its DNA intercalating nature.A catalyst composition for the feasible elimination of ethidium bromide using...Ethidium bromide is a fluorescent tag and is used in biomedical applications.It is a potent mutagen because of its DNA intercalating nature.A catalyst composition for the feasible elimination of ethidium bromide using a broad spectrum of solar radiation was investigated.Nanostructured anatase TiO2 was synthesized by gel to crystalline conversion and its bandgap was engineered by doping with zirconium to effectively harness sunlight.The doped nanocrystals were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,energy dispersive X-ray analysis,and UV-Vis spectroscopy.The formed crystals retained the anatase phase with a marginal increase in size.The pulverization process used to dope Zr into titania resulted in a nano and doped lattice with an increased and extended light absorption range,which gave a nearly five-fold increase in photoactivity over pure titania.The catalytic effect of the modified titania,the dopant concentration,and the dynamics of the dopant concentration on the charge carriers(trapping-recombination)for the degradation of the mutagen was investigated.The modified titania is capable of total ethidium bromide elimination in sunlight.The loss of its mutagenic property was confirmed by an Ames test.The induced revertant colonies observed were nil in the treated sample indicating a complete loss of the intercalating property of the mutagen.展开更多
文摘Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential protective effects of Spirulina platensis(SP)against the effects of EtBr toxicity in the Nile tilapia(Oreochromis niloticus)fry.Fry were divided to five groups,viz.,a control and four treatment groups of low-dose EtBr(10μg/L),low-dose EtBr with SP(10μg/L EtBr+200 mg/L SP),high-dose EtBr(100μg/L),and high-dose EtBr with SP(100μg/L EtBr+200 mg/L SP);the exposure period was 2 weeks.Low and high doses of EtBr induced alterations in some hematological,biochemical,and histopathological parameters.Necrotic hepatocytes,degenerated area,vacuolated hepatocytes,pyknotic nuclei,constricted and dilated blood sinusoids,and infiltration of inflammatory cells were observed.Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP,but it was increased in groups exposed to high doses of EtBr and EtBr with SP,compared with the control group.After feeding with SP,most histological and histochemical parameters restored to normal values.Therefore,SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.
基金Project supported by the Ninth Five-Year Plan Key Project Grant of the Chinese Academy of Sciences
文摘Under different conditions, oligonucleotides can form several alternative DNA structures such as duplex, triplex and quadruplex. All these structures can interact with ethidium bromide (EB) and make its fluorescence intensity change. The fluorescence spectra and other related parameters provided by static fluorescence techniques showed that the interaction mechanisms between EB and these structures were not always the same. Among them, B type duplex and triplex DNA adopt an intercalative mode when binding to the EB, which has a relatively high efficiency of energy transfer and the fluorescence of EB cannot be quenched easily. While for the parallel duplex DNA, the interaction mode is an outside binding in which energy transfer can hardly happen and its fluorescence intensity as well as Stern-Volmer constant is almost the same to the free EB. For the quadruplex, the binding mechanism to EB is more complex. Results from the energy transfer and quenching studies indicate that the two interaction modes noted above probably coexist at the same time.
基金the Eighth Five-Year Plan's Key Basic Research Project of Academia Sinica
文摘The preparations,the formation conditions and stabilities of duplex dA_(10)·dT_(10)and triplax dA_(10)·2dT_(10),and the interactions of ethidium bromide with them in an appropriate buffer are reported.Flu- orescence spectra show that ethidium can be used as a useful fluorescence probe to detect triplex formation, and its fluorescence is significantly increased by either the duplex or triplex,but less in the case of the triplex.Thermal denaturation profiles demonstrate that the stability of the triplex is enhanced by ethidium. Fluorescence energy transfer studies suggest the existence of similar energy transfer from the triplex or du- plex to the bound ethidium but the presence of the triplex results in substantially smaller energy transfer than that of the duplex does.Furthermore,fluorescence quenching using the anionic quencher[Fe(CN)_6]^(4-)can- not decrease the fluorescence intensities of triplex/ethidium complex.These results demonstrate that ethidi- um has significantly binding affinity with the triplex,and interacts with it via intercalative mechanism,thus increases its stability.
文摘The luminous intensity of dark variant (S1) separated from photobacterium phosph oreum (A2) was 1/10 000 less than that of wild type. Ethidium bromide (EB) (0.6 mg/L), Mytomycin C (MC, 0.05 mg/L), 2 amino fluorene (2 AF, 1.0 mg/L) all cou ld strongly induce reversion mutation for S1 within 24 h and increase reversion ratio significantly. The results of experiments indicated that these revertants had stable genetic characteristic and the mutation may take place at gene levels . The mutagenesis to S1 caused by EB, MC and 2 AF was detected and it may be us ed as a new rapid, simple and sensitive method for gene toxicant monitoring.
文摘Taking advantage of the effects on DNA secondary structure of two DNA-intercalators,ethidium bromide and chloroquine,we used each of them to treat nuclei from both mature erythrocytes and reticulocytes of chicken,as an alternative approach to study the relationships between DNA secondary structure,nuclear proteins and chromatin structure.We presented results of differential extraction of nuclear proteins from nuclei with DNA-intercalators,as well as preliminary characterization of these proteins.A 45kd protein is the major component in fractions extracted by both intercalators from nuclei from either mature erythrocytes or reticulocytes and seems to be a DNA-binding protein.Furthermore,from current concepts of functional aspects of DNA conformation and structural heterogeneity in chromatin and nuclear proteins,we have discussed both the significance of our results as well as technical aspects of this approach.
基金Visvesvaraya Technological University,Belgaum,and the Center for Emerging Technologies,Jain University,Bangalore as well as Naveen, Jain University for their support and for a Grant-in-aid to carry out the research work described in this paper
文摘Ethidium bromide is a fluorescent tag and is used in biomedical applications.It is a potent mutagen because of its DNA intercalating nature.A catalyst composition for the feasible elimination of ethidium bromide using a broad spectrum of solar radiation was investigated.Nanostructured anatase TiO2 was synthesized by gel to crystalline conversion and its bandgap was engineered by doping with zirconium to effectively harness sunlight.The doped nanocrystals were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,energy dispersive X-ray analysis,and UV-Vis spectroscopy.The formed crystals retained the anatase phase with a marginal increase in size.The pulverization process used to dope Zr into titania resulted in a nano and doped lattice with an increased and extended light absorption range,which gave a nearly five-fold increase in photoactivity over pure titania.The catalytic effect of the modified titania,the dopant concentration,and the dynamics of the dopant concentration on the charge carriers(trapping-recombination)for the degradation of the mutagen was investigated.The modified titania is capable of total ethidium bromide elimination in sunlight.The loss of its mutagenic property was confirmed by an Ames test.The induced revertant colonies observed were nil in the treated sample indicating a complete loss of the intercalating property of the mutagen.
