Ki Hong Kim - Academia.edu (original) (raw)

Papers by Ki Hong Kim

Fish Physiology and Biochemistry, 2006

A full-length complementary DNA clone encoding copper, zinc superoxide dismutase (Cu, Zn-SOD), a ... more A full-length complementary DNA clone encoding copper, zinc superoxide dismutase (Cu, Zn-SOD), a key antioxidant enzyme, was isolated from the evolutionary lower vertebrate shark species, Scyliorhinus torazame. The shark SOD cDNA comprised 30 bp of 5′-untranslated region (UTR), 456 bp of a single open reading frame (ORF) encoding 152 amino acids and 401 bp of 3′-UTR, including consensus polyadenylation signal (AATAAA) and 20 bp of poly-(A+) tail. Deduced amino acid sequence of shark SOD shared relatively high identities with those not only from teleosts (57–72%) but also from other advanced vertebrates (53–65%) with intermediate characteristics. In addition, shark SOD represented unique molecular features that were not seen in other vertebrate SODs. The SOD transcripts were expressed ubiquitously in all tissues examined, including brain, intestine, kidney, liver, muscle and spleen, as determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Acute exposure to cadmium by either injection (0, 1, 2 or 5 mg CdCl2 kg−1 body weight for 2 days) or immersion (0 or 25 μM Cd for 0, 1, 4 and 7 days) altered hepatic SOD mRNA level, based on RNA blot hybridization and semi-quantitative and/or real-time RT-PCR assays. Transcriptional levels of SOD were significantly increased by cadmium exposure generally in a dose- or time-dependent fashion.

Marine Biotechnology, 2005

Novel metallothionein (MT) complementary DNA and genomic sequences were isolated from a cartilagi... more Novel metallothionein (MT) complementary DNA and genomic sequences were isolated from a cartilaginous shark species, Scyliorhinus torazame. The full-length open reading frame (ORF) of shark MT cDNA encoded 68 amino acids with a high cysteine content (29%). The genomic ORF sequence (932 bp) of shark MT isolated by polymerase chain reaction (PCR) comprised 3 exons with 2 interventing introns. Shark MT sequence shared many conserved features with other vertebrate MTs: overall amino acid identities of shark MT ranged from 47% to 57% with fish MTs, and 41% to 62% with mammalian MTs. However, in addition to these conserved characteristics, shark MT sequence exhibited some unique characteristics. It contained 4 extra amino acids (Lys-Ala-Gly-Arg) at the end of the β-domain, which have not been reported in any other vertebrate MTs. The last amino acid residue at the C-terminus was Ser, which also has not been reported in fish and mammalian MTs. The MT messenger RNA levels in shark liver and kidney, assessed by semiquantitative reverse transcriptase PCR and RNA blot hybridization, were significantly affected by experimental exposures to heavy metals (cadmium, copper, and zinc). Generally, the transcriptional activation of shark MT gene was dependent on the dose (0–10 mg/kg body weight for injection and 0–20 μM for imme-rsion) and duration (1–10 days); zinc was a more potent inducer than copper and cadmium.

Fish & Shellfish Immunology, 2007

The present study aimed to develop a method of quantification of heat shock protein transcript le... more The present study aimed to develop a method of quantification of heat shock protein transcript levels in the estuarine copepod Eurytemora affinis. For that, the fulllength cDNA of the 78-kDa glucose-regulated protein (Ea-grp78) and the cytosolic 90-kDa heat shock protein (Ea-hsp90A) from this species have been cloned. These cDNA revealed, respectively, 2,370 and 2,299 bp with 1,971 and 2,124 bp open reading frames encoding 656 and 707 amino acids. Main features, sequence identities and phylogenetic analysis with other species were described. Then, the expression profiles were analysed using reverse transcription/ real-time quantitative PCR method from copepods subjected to different thermic and osmotic stresses in laboratory, and from copepods directly sampled into the natural population of the Seine Estuary (France) along a salinity gradient. Thermic shock (7.5°C, 22.5°C and 30°C during 90 min) significantly induced increases of transcript quantities ranged between 1.7-and 19.7-fold the levels observed in control conditions (15°C). Hypo-and hyper-osmotic shocks (salinities of 1 and 30 during 90 min) caused a 2-fold induction of Ea-hsp90A transcript level in comparison to controls (salinity of 15) whereas no significant change was measured for Ea-grp78. On the other hand, similar expression profiles were observed for the two transcripts after 72 h of exposition to salinities of 1 and 25 with a significant 2fold induction observed for the lower salinity. To finish, strong expression inductions of both Ea-grp78 and Ea-hsp90A genes were observed in field copepods sampled at low salinity during the campaigns of June 2009 and May 2010. These results tend to show that the low salinity and the increase of temperature seem to have a synergic effect on stress condition of copepods.

Aquaculture, 2006

A full-length complementary DNA clone (789 bp) encoding Cu/Zn superoxide dismutase (Cu/Zn SOD) wa... more A full-length complementary DNA clone (789 bp) encoding Cu/Zn superoxide dismutase (Cu/Zn SOD) was isolated from the liver cDNA library of a marine fish, rockbream (Oplegnathus fasciatus). The rockbream SOD cDNA contained a 462 bp open reading frame (ORF) encoding 154 amino acids. Deduced amino acid sequence of rockbream SOD shared relatively high identity with teleost (78-91%) and mammalian (64-70%) orthologues. The SOD transcripts were ubiquitously detected in all the tissues examined including brain, gill, intestine, kidney, liver, muscle, skin and spleen determined by RT-PCR and northern dot blot hybridization. Based on semi-quantitative RT-PCR, real-time PCR and/or scanning densitometry of RNA dot blot hybridization, the transcriptional level of SOD gene was differentially affected by various experimental exposures to heavy metals. Intraperitoneal injections (0, 1, 2, 5 or 10 mg CdCl 2 per kg body weight for 48 h) and immersion treatments (0, 25, 50 or 100 AM of cadmium, copper or zinc for 96 h) revealed that (1) the expression of SOD at mRNA level was generally dependent upon the exposure doses of heavy metals, (2) the stimulation of SOD transcripts was more apparent in liver than kidney and gill, and (3) that cadmium was more potent to induce the expression of SOD than copper and zinc. Immersion exposures using high (25 AM Cd) and low (2 or 5 AM) doses of cadmium for prolonged periods up to 14 (high dose) or 28 (low doses) days also showed that the levels of SOD transcripts were higher with longer durations and higher concentrations. Results from the present study indicate that assessment of transcriptional activity of fish SOD gene at mRNA level might be useful as a sensitive molecular biomarker system to address the oxidative stress caused by heavy metal pollutants in fish. D

Fish Physiology and Biochemistry, 2006

A full-length complementary DNA clone encoding copper, zinc superoxide dismutase (Cu, Zn-SOD), a ... more A full-length complementary DNA clone encoding copper, zinc superoxide dismutase (Cu, Zn-SOD), a key antioxidant enzyme, was isolated from the evolutionary lower vertebrate shark species, Scyliorhinus torazame. The shark SOD cDNA comprised 30 bp of 5′-untranslated region (UTR), 456 bp of a single open reading frame (ORF) encoding 152 amino acids and 401 bp of 3′-UTR, including consensus polyadenylation signal (AATAAA) and 20 bp of poly-(A+) tail. Deduced amino acid sequence of shark SOD shared relatively high identities with those not only from teleosts (57–72%) but also from other advanced vertebrates (53–65%) with intermediate characteristics. In addition, shark SOD represented unique molecular features that were not seen in other vertebrate SODs. The SOD transcripts were expressed ubiquitously in all tissues examined, including brain, intestine, kidney, liver, muscle and spleen, as determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Acute exposure to cadmium by either injection (0, 1, 2 or 5 mg CdCl2 kg−1 body weight for 2 days) or immersion (0 or 25 μM Cd for 0, 1, 4 and 7 days) altered hepatic SOD mRNA level, based on RNA blot hybridization and semi-quantitative and/or real-time RT-PCR assays. Transcriptional levels of SOD were significantly increased by cadmium exposure generally in a dose- or time-dependent fashion.

Marine Biotechnology, 2005

Novel metallothionein (MT) complementary DNA and genomic sequences were isolated from a cartilagi... more Novel metallothionein (MT) complementary DNA and genomic sequences were isolated from a cartilaginous shark species, Scyliorhinus torazame. The full-length open reading frame (ORF) of shark MT cDNA encoded 68 amino acids with a high cysteine content (29%). The genomic ORF sequence (932 bp) of shark MT isolated by polymerase chain reaction (PCR) comprised 3 exons with 2 interventing introns. Shark MT sequence shared many conserved features with other vertebrate MTs: overall amino acid identities of shark MT ranged from 47% to 57% with fish MTs, and 41% to 62% with mammalian MTs. However, in addition to these conserved characteristics, shark MT sequence exhibited some unique characteristics. It contained 4 extra amino acids (Lys-Ala-Gly-Arg) at the end of the β-domain, which have not been reported in any other vertebrate MTs. The last amino acid residue at the C-terminus was Ser, which also has not been reported in fish and mammalian MTs. The MT messenger RNA levels in shark liver and kidney, assessed by semiquantitative reverse transcriptase PCR and RNA blot hybridization, were significantly affected by experimental exposures to heavy metals (cadmium, copper, and zinc). Generally, the transcriptional activation of shark MT gene was dependent on the dose (0–10 mg/kg body weight for injection and 0–20 μM for imme-rsion) and duration (1–10 days); zinc was a more potent inducer than copper and cadmium.

Fish & Shellfish Immunology, 2007

The present study aimed to develop a method of quantification of heat shock protein transcript le... more The present study aimed to develop a method of quantification of heat shock protein transcript levels in the estuarine copepod Eurytemora affinis. For that, the fulllength cDNA of the 78-kDa glucose-regulated protein (Ea-grp78) and the cytosolic 90-kDa heat shock protein (Ea-hsp90A) from this species have been cloned. These cDNA revealed, respectively, 2,370 and 2,299 bp with 1,971 and 2,124 bp open reading frames encoding 656 and 707 amino acids. Main features, sequence identities and phylogenetic analysis with other species were described. Then, the expression profiles were analysed using reverse transcription/ real-time quantitative PCR method from copepods subjected to different thermic and osmotic stresses in laboratory, and from copepods directly sampled into the natural population of the Seine Estuary (France) along a salinity gradient. Thermic shock (7.5°C, 22.5°C and 30°C during 90 min) significantly induced increases of transcript quantities ranged between 1.7-and 19.7-fold the levels observed in control conditions (15°C). Hypo-and hyper-osmotic shocks (salinities of 1 and 30 during 90 min) caused a 2-fold induction of Ea-hsp90A transcript level in comparison to controls (salinity of 15) whereas no significant change was measured for Ea-grp78. On the other hand, similar expression profiles were observed for the two transcripts after 72 h of exposition to salinities of 1 and 25 with a significant 2fold induction observed for the lower salinity. To finish, strong expression inductions of both Ea-grp78 and Ea-hsp90A genes were observed in field copepods sampled at low salinity during the campaigns of June 2009 and May 2010. These results tend to show that the low salinity and the increase of temperature seem to have a synergic effect on stress condition of copepods.

Aquaculture, 2006

A full-length complementary DNA clone (789 bp) encoding Cu/Zn superoxide dismutase (Cu/Zn SOD) wa... more A full-length complementary DNA clone (789 bp) encoding Cu/Zn superoxide dismutase (Cu/Zn SOD) was isolated from the liver cDNA library of a marine fish, rockbream (Oplegnathus fasciatus). The rockbream SOD cDNA contained a 462 bp open reading frame (ORF) encoding 154 amino acids. Deduced amino acid sequence of rockbream SOD shared relatively high identity with teleost (78-91%) and mammalian (64-70%) orthologues. The SOD transcripts were ubiquitously detected in all the tissues examined including brain, gill, intestine, kidney, liver, muscle, skin and spleen determined by RT-PCR and northern dot blot hybridization. Based on semi-quantitative RT-PCR, real-time PCR and/or scanning densitometry of RNA dot blot hybridization, the transcriptional level of SOD gene was differentially affected by various experimental exposures to heavy metals. Intraperitoneal injections (0, 1, 2, 5 or 10 mg CdCl 2 per kg body weight for 48 h) and immersion treatments (0, 25, 50 or 100 AM of cadmium, copper or zinc for 96 h) revealed that (1) the expression of SOD at mRNA level was generally dependent upon the exposure doses of heavy metals, (2) the stimulation of SOD transcripts was more apparent in liver than kidney and gill, and (3) that cadmium was more potent to induce the expression of SOD than copper and zinc. Immersion exposures using high (25 AM Cd) and low (2 or 5 AM) doses of cadmium for prolonged periods up to 14 (high dose) or 28 (low doses) days also showed that the levels of SOD transcripts were higher with longer durations and higher concentrations. Results from the present study indicate that assessment of transcriptional activity of fish SOD gene at mRNA level might be useful as a sensitive molecular biomarker system to address the oxidative stress caused by heavy metal pollutants in fish. D