Purification, N-terminal amino acid sequence, and some properties of Cu, Zn-superoxide dismutase from Japanese flounder (Paralichthys olivaceus) hepato-pancreas

Transcriptional regulation of the Japanese flounder Cu,Zn-SOD (Jfsod1) gene in RAW264.7 cells during oxidative stress caused by causative bacteria of edwardsiellosis

Edwardsiellosis is one of the most important bacterial diseases in fish, sometimes causing extensive economic losses in the aquaculture industry. Our previous studies demonstrated that the Cu,Zn-SOD (sod1) activity has significantly increased in Japanese flounder, Paralichthys olivaceus, hepatopancreas infected by causative bacteria of edwardsiellosis Edwardsiella tarda NUF251. In this study, NUF251 stimulated intracellular superoxide radical production in mouse macrophage RAW264.7 cells, which was reduced by N-acetylcysteine. This result suggests that NUF251 infection causes oxidative stress. To evaluate the regulatory mechanism of Jfsod1 at transcriptional levels under oxidative stress induced by NUF251 infection, we cloned and determined the nucleotide sequence (1124 bp) of the 5'-flanking region of the Jfsod1 gene. The sequence analysis demonstrated that the binding sites for the transcription factors C/EBPα and NF-IL6 involved in the transcriptional regulation of the mammalian sod1 gene existed. We constructed a luciferase reporter system with the 5'-flanking region (-1124/-1) of the Jfsod1 gene, and a highly increased transcriptional activity of the region was observed in NUF251-infected RAW264.7 cells. Further studies using several mutants indicated that deletion of the recognition region of NF-IL6 (-272/-132) resulted in a significant decrease in the transcriptional activity of the Jfsod1 gene in NUF251-infected RAW264.7 cells. In particular, the binding site (-202/-194) for NF-IL6 might play a major role in upregulating the transcriptional activity of the 5'-flanking region of the Jfsod1 gene in response to oxidative stress induced by NUF251 infection. These results could be provided a new insight to understand the pathogenic mechanism of causative bacteria of edwardsiellosis.

The study of acidic/basic nature of metallothioneins and other metal-binding biomolecules in the soluble hepatic fraction of the northern pike (Esox lucius)

Since fish metalloproteins are still not thoroughly characterized, the aim of this study was to investigate the acidic/basic nature of biomolecules involved in the sequestration of twelve selected metals in the soluble hepatic fraction of an important aquatic bioindicator organism, namely the fish species northern pike (Esox lucius). For this purpose, the hyphenated system HPLC-ICP-MS was applied, with chromatographic separation based on anion/cation-exchange principle at physiological pH (7.4). The results indicated predominant acidic nature of metal-binding peptides/proteins in the studied hepatic fraction. More than 90 % of Ag, Cd, Co, Cu, Fe, Mo, and Pb were eluted with negatively charged biomolecules, and >70 % of Bi, Mn, and Zn. Thallium was revealed to bind equally to negatively and positively charged biomolecules, and Cs predominantly to positively charged ones. The majority of acidic (negatively charged) metalloproteins/peptides were coeluted within the elution time range of applied standard proteins, having pIs clustered around 4-6. Furthermore, binding of several metals (Ag, Cd, Cu, Zn) to two MT-isoforms was assumed, with Cd and Zn preferentially bound to MT1 and Ag to MT2, and Cu evenly distributed between the two. The results presented here are the first of their kind for the important bioindicator species, the northern pike, as well as one of the rare comprehensive studies on the acidic/basic nature of metal-binding biomolecules in fish, which can contribute significantly to a better understanding of the behaviour and fate of metals in the fish organism, specifically in liver as main metabolic and detoxification organ.

Flounder fish (Paralichthys sp.) collagen a new tissue regeneration: genotoxicity, cytotoxicity and physical-chemistry characterization

Collagen dressings have been widely used as effective treatments for chronic wounds acting as barrier, protecting the area from infections and participating in the healing process. Collagen from fish skin is biocompatible, presents low immunogenicity and is able of stimulating wound healing. In this scenario, skin of flounder fish (Paralichthys sp.) may constitute a promising source for collagen. Then, our hypothesis is that fish collagen is able of increasing cell proliferation, with no cytotoxicity. In this context, the aim of the present study was to investigate the physicochemical and morphological properties of collagen using scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), mass loss and pH. Moreover, the cytotoxicity and genotoxicity of collagen were studied using in vitro studies (cell viability, comet assay and micronucleus assay). Fish collagen showed no variation of pH and mass weight, with characteristic peaks of collagen in FTIR. Furthermore, all the extracts presented cell viability at least over 50% and no cytotoxicity was observed. Regarding genotoxicity data, the results showed that only the extract of 100% showed higher values in comparison with negative control group for CHO-K1 cell line as depicted by comet and micronucleus assays. Based on the results, it is suggested that fish collagen is biocompatible and present non-cytotoxicity in the in vitro studies, being considered a suitable material for tissue engineering proposals.

Copper/Zinc Superoxide Dismutase from the Crocodile Icefish Chionodraco hamatus: Antioxidant Defense at Constant Sub-Zero Temperature

In the present study, we describe the purification and molecular characterization of Cu,Zn superoxide dismutase (SOD) from Chionodraco hamatus, an Antarctic teleost widely distributed in many areas of the Ross Sea that plays a pivotal role in the Antarctic food chain. The primary sequence was obtained using biochemical and molecular biology approaches and compared with Cu,Zn SODs from other organisms. Multiple sequence alignment using the amino acid sequence revealed that Cu,Zn SOD showed considerable sequence similarity with its orthologues from various vertebrate species, but also some specific substitutions directly linked to cold adaptation. Phylogenetic analyses presented the monophyletic status of Antartic Teleostei among the Perciformes, confirming the erratic differentiation of these proteins and concurring with the theory of the "unclock-like" behavior of Cu,Zn SOD evolution. Expression of C. hamatus Cu,Zn SOD at both the mRNA and protein levels were analyzed in various tissues, highlighting the regulation of gene expression related to environmental stress conditions and also animal physiology. The data presented are the first on the antioxidant enzymes of a fish belonging to the Channichthyidae family and represent an important starting point in understanding the antioxidant systems of these organisms that are subject to constant risk of oxidative stress.

Molecular cloning and functional characterization of a Cu/Zn superoxide dismutase from jellyfish Cyanea capillata

We identified and characterized a novel superoxide dismutase (SOD), designated as CcSOD1, from the cDNA library from the tentacle tissue of the jellyfish Cyanea capillata. The full-length cDNA sequence of CcSOD1 consists of 745 nucleotides with an open reading frame encoding a mature protein of 154 amino acids, sharing a predicted structure similar to the typical Cu/Zn-SODs. The CcSOD1 coding sequence was cloned into the expression vector pET-24a and successfully expressed in Escherichia coli Rosetta (DE3) pLysS. The recombinant protein rCcSOD1 was purified by HisTrap High Performance chelating column chromatography and analyzed for its biological function. Our results showed that the purified rCcSOD1 could inhibit superoxide anion and keep active in a pH interval of 4.5-9 and a temperature interval of 10-70°C. Even when heated at 70°C for 60 min, rCcSOD1 retained 100% activity, indicating a relatively high thermostability. These results suggest that CcSOD1 protein may play an important role in protecting jellyfish from oxidative damage and can serve as a new resource for antioxidant products.

Use of Cu/Zn-superoxide dismutase tool for biomonitoring marine environment pollution in the Persian Gulf and the Gulf of Oman

Superoxide dismutase (SOD) is the pivotal antioxidant enzyme that defends organisms against the oxidative stresses of superoxide radicals. In this experimental study, purification of SOD from the leaves of Avicennia marina (grey mangrove or white mangrove) from the family Acanthaceae, located in Sirik mangrove forest on the shore of the Gulf of Oman was performed, for the intended characterization of SOD. The Sirik AmSOD (A. marina SOD) expressed optimum activity in the pH range of 6-9 with the maximum activity at pH 8. The optimal temperature for Sirik AmSOD activity was 70°C. Comparison of the pH and temperature optima in two regions (the Persian Gulf and the Gulf of Oman) showed significant differences with P<0.05. The SOD from the Persian Gulf was more resistant against the environmental stressors, because of the biochemical adaption to this environment, which is harsher. The evidence from these results suggests that AmSOD has different characteristics in each place, and mangroves undergo different adaptations and require different protections. The results of the enzymatic research can be useful for ecological management of organisms.

Superoxide dismutases from larvae of the camel tick Hyalomma dromedarii

Three superoxide dismutases (EC 1.15.1.1) (TLSOD1, TLSOD2 and TLSOD3) were purified from larvae of the camel tick Hyalomma dromedarii by ammonium sulfate precipitation, ion exchange and gel filtration columns. SDS-PAGE revealed that the subunit molecular masses of the SODs are 40±2 kDa, 67±1.5 kDa and 45±2.6 kDa for TLSOD1, TLSOD2 and TLSOD3, respectively. TLSOD1 and TLSOD2 are monomeric proteins, while TLSOD3 isoenzyme exhibits dimeric structure with native molecular mass of 90 kDa. The pI values are estimated at pH 8.0, pH 7.2 and pH 6.6 for the three SODs which displayed pH optima at 7.6, 8.0 and 7.8, respectively. CuCl(2) and ZnCl(2) increase the activity of TLSOD2 and TLSOD3, while MnCl(2) increases the activity of TLSOD1. KCN inhibits the activity of TLSOD2 and TLSOD3, while a remarkable resistance of TLSOD1 isoenzyme was detected. TLSOD1 is suggested to be a manganese containing isoenzyme while TLSOD2 and TLSOD3 are suggested to be copper/zinc-containing isoenzymes. These results indicate the presence of three different forms of SODs in the larval stage of camel tick. This finding will contribute to our understanding of the physiology of these ectoparasites and the development of non-traditional methods to control them.

Antioxidant enzymatic defenses and oxidative damage in Dentex dentex fed on different dietary macronutrient levels

A wide range of antioxidant mechanisms are present in fish maintaining an adequate "oxidative balance". When this balance tilts in favor of the oxidant agents "oxidative stress" arises with detrimental effects in molecules of great biological importance. Little has been reported about the influence of different dietary energy sources on antioxidant defenses in fish. The influence of different dietary macronutrient combinations on the key antioxidant enzyme activity, the oxidative damage to lipids and proteins and the possible modifications in the SOD isoenzymatic pattern were evaluated in liver, white muscle, heart and erythrocytes of common dentex (Dentex dentex). Four experimental diets with different protein:lipid:carbohydrate ratios (43/16/28; 43/24/4; 38/19/28 and 38/24/13) were formulated. In general, neither different dietary macronutrient levels nor the interaction among them induces substantial modifications in enzymatic antioxidant defense mechanisms. Two constitutive SOD isoforms, CuZn-SOD I and Mn-SOD, were detected in the tissues analyzed in all experimental groups, independently of diet formulation, but, a third SOD isoenzyme, CuZn-SOD II seems to be induced in white muscle by higher dietary protein levels. Densitometric analyses of western blotting membranes revealed higher CuZn-SOD expression in the heart of dentex fed on lower dietary protein levels, although these differences did not correlate with the SOD activity. Finally, a direct relation exists between the lipid or protein intake level and occurrence of oxidative damage in different tissue components.

Cu,Zn superoxide dismutase from Trematomus bernacchii: functional conservation and erratic molecular evolution in Antarctic teleosts

In the present study, we describe the purification and molecular characterization of Cu,Zn superoxide dismutase (SOD) from Trematomus bernacchii, a teleost widely distributed in many areas of Antarctica, that plays a pivotal role in the Antarctic food chain. The amino acid and cDNA sequences have been obtained using both biochemical and molecular biology approaches and are compared with Cu,Zn SODs from other fishes. Assessment of the primary sequences highlights that the catalytically important residues are fully conserved in Cu,Zn SOD from T. bernacchii. Phylogenetic analyses performed on Cu,Zn SOD amino acid sequences permit speculation regarding the evolution of this protein. In particular, the data confirms the erratic differentiation of these proteins and concurs with the theory of the "unclock-like" behaviour of Cu,Zn SOD evolution.

Primary structure and properties of Mn-superoxide dismutase from scallop adductor muscle

Manganese-superoxide dismutase was purified to homogeneity from scallop adductor muscle using DEAE-Sephacel, Buthyl-Cellulofine and Superdex 200 pg column chromatographies. The molecular weights of the purified enzyme were calculated to be 22,321.4 according to time-of-flight mass spectrometry, and to be approximately 95,000 and 93,000 on Superdex 200 pg column chromatography and non-denatured PAGE, respectively, and were calculated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 24,000 and 25,000 in the absence and 25,000 in the presence of beta-mercaptoethanol. These findings suggested that the native enzyme is composed of four identical subunits. Other properties of scallop adductor muscle manganese-superoxide dismutase, including pH stability and heat stability, were also determined. We determined the partial amino acid sequences of purified manganese-superoxide dismutase using digestions by bromocyan and lysyl endopeptidase and also determined the manganese-superoxide dismutase cDNA structure. The amino acid sequence of the enzyme obtained using both methods showed homology to those of vertebrates such as human, bovine, chicken, Xenopus and zebrafish manganese-superoxide dismutases (64.91, 65.35, 64.47, 63.27 and 64.60%, respectively). We also predicted the 3D structure of scallop adductor muscle manganese-superoxide dismutase using molecular operating environment and compared its structure with those of other manganese-superoxide dismutases. The overall structure of scallop adductor muscle manganese-superoxide dismutase was very similar to those of other species, including human and Aspergillus.

Purification and some properties of superoxide dismutase from Deinococcus radiophilus, the UV-resistant bacterium

The superoxide dismutase (SOD, EC 1.15.1.1) of Deinococcus radiophilus, a bacterium extraordinarily resistant to UV, ionizing radiations, and oxidative stress, was purified 1,920-fold with a 58% recovery yield from the cell-free extract of stationary cells by steps of ammonium sulfate fractionation and Superdex G-75 gel-filtration chromatography. A specific activity of the purified enzyme preparation was ca. 31,300 U mg(-1) protein. D. radiophilus SOD is Mn/FeSOD, judging by metal analysis and its insensitivity to cyanide and a partial sensitivity to H2O2. The molecular weights of the purified enzyme estimated by gel chromatography and polyacrylamide gel electrophoresis are 51.5+/-1 and 47.1+/-5 kDa, respectively. The SOD seems to be a homodimeric protein with a molecular mass of 26 +/- 0.5 kDa per monomer. The purified native SOD showed very acidic pI of ca. 3.8. The enzyme was stable at pH 5.0-11.0, but quite unstable below pH 5.0. SOD was thermostable up to 40 degrees C, but a linear reduction in activity above 50 degrees C. Inhibition of the purified SOD activity by beta-naphthoquinone-4-sulfonic acid, rho-diazobenzene sulfonic acid, and iodine suggests that lysine, histidine, and tyrosine residues are important for the enzyme activity. The N-terminal peptide sequence of D. radiophilus Mn/FeSOD (MAFELPQLPYAYDALEPHIDA(> D) is strikingly similar to those of D. radiodurans MnSOD and Aerobacter aerogenes FeSOD.