Immunostimulatory Effects of Korean Mineral-Rich Seawaters on Cyclophosphamide-Induced Immunosuppression in Mice.

Deep seawater (DS), obtained from a depth over 200 m, has health benefits due to its rich nutrients and minerals, and intake of DS has shown diverse immunomodulatory effects in allergies and cancer. Therefore, the immunostimulatory effects of Korean mineral-rich seawaters were examined in a cyclophosphamide (CPA)-induced immunosuppression model. Three samples of Korean seawater, namely DS from the East Sea off the coasts of Pohang (PDS) and Uljin (UDS), and seawater from the West Sea off the coast of Boryeong (BS), were collected. The seawaters were abundant in several minerals (calcium, iron, zinc, selenium, etc.). Mice were orally administered the seawaters for 42 days, followed by CPA-induced immunosuppression. The CPA induction reduced the weight of the spleen and lymph nodes; however, the administration of seawaters increased the weight of the lymphoid organs, accompanied by stimulation of natural killer cells' activity and NF-kB-mediated cytokine production (IFNγ, TNFα, IL1ß, IL6, and IL12). The mouse-derived splenocytes showed lymphoproliferation without cytotoxicity in the seawater groups. Histopathological analysis revealed that the seawaters improved the CPA-induced atrophic changes by promoting lymphoproliferation in the spleen and lymph nodes. These results provide useful information for the use of Korean mineral-rich seawaters, particularly PDS and UDS, as alternative immunostimulants under immunosuppressive conditions.

How Do Brown Seaweeds Work on Biomarkers of Dyslipidemia? A Systematic Review with Meta-Analysis and Meta-Regression.

Dyslipidemia is a common chronic disease that increases the risk of cardiovascular disease. Diet plays an important role in the development of dyslipidemia. As people pay increased attention to healthy eating habits, brown seaweed consumption is increasing, particularly in East Asian countries. The association between dyslipidemia and brown seaweed consumption has been previously demonstrated. We searched for keywords associated with brown seaweed and dyslipidemia in electronic databases such as PubMed, Embase, and Cochrane. Heterogeneity was estimated using the I2 statistic. The 95% confidence interval (CI) of the forest plot and heterogeneity were confirmed using meta-ANOVA and meta-regression. Funnel plots and publication bias statistical tests were used to determine publication bias. Statistical significance was set at p < 0.05. In this meta-analysis, we found that brown seaweed intake significantly decreased the levels of total cholesterol (mean difference (MD): -3.001; 95% CI: -5.770, -0.232) and low-density lipoprotein (LDL) cholesterol (MD: -6.519; 95% CI: -12.884, -0.154); nevertheless, the statistically significant association of brown seaweed intake with high-density lipoprotein (HDL) cholesterol and triglycerides were not observed in our study (MD: 0.889; 95% CI: -0.558, 2.335 and MD: 8.515; 95% CI: -19.354, 36.383). Our study demonstrated that brown seaweed and its extracts decreased total cholesterol and LDL cholesterol levels. The use of brown seaweeds may be a promising strategy to reduce the risk of dyslipidemia. Future studies involving a larger population are warranted to investigate the dose-response association of brown seaweed consumption with dyslipidemia.

Do red tide events promote an increase in zooplankton biodiversity?

Red tides occurring off the southern coast of Korea impact the marine ecosystem and aquaculture industries. Zooplankton are crucial in the food web, connecting primary producers to higher predators and interact diversely with red tide organisms. This study explores dynamics of the zooplankton community over seven years including three red tide and four non-red tide years in Tongyeong using metabarcoding. In non-red tide years, zooplankton diversity showed typical seasonal patterns, increasing from June to early October. However, during red tide years, diversity remained high, with a shift in species composition-decreased Copepoda and increased Branchiopoda, Echinodermata, Malacostraca, and Annelida. Diversity indices were significantly higher in red tide years across all periods except for the richness in "after" that showed an insignificant higher value. The differences in zooplankton assemblages across periods were influenced by surface temperatures and the density of the red tide-causing alga Margalefidinium polykrikoides. Eight species emerged as indicator species and showed direct correlations with M. polykrikoides and among them, seven species were indicator species for red tide occurrence years. The ecological characteristics of M. polykrikoides blooms and their recurrent occurrences over several decades suggest that zooplankton may adapt to the toxins and use these blooms as spawning cues. Overall, this study provides comprehensive understanding on changes in zooplankton communities during red tide events, offering novel insights into their ecology.

Identification and characterization of epoxide hydrolase activity of polycyclic aromatic hydrocarbon-degrading bacteria for biocatalytic resolution of racemic styrene oxide and styrene oxide derivatives.

A novel epoxide hydrolase (EHase) from polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was identified and characterized. EHase activity was identified in four strains of PAH-degrading bacteria isolated from commercial gasoline and oil-contaminated sediment based on their growth on styrene oxide and its derivatives, such as 2,3- and 4-chlorostyrene oxides, as a sole carbon source. Gordonia sp. H37 exhibited high enantioselective hydrolysis activity for 4-chlorostyrene oxide with an enantiomeric ratio of 27. Gordonia sp. H37 preferentially hydrolyzed the (R)-enantiomer of styrene oxide derivatives resulting in the preparation of a (S)-enantiomer with enantiomeric excess greater than 99.9 %. The enantioselective EHase activity was identified and characterized in various PAH-degrading bacteria, and whole cell Gordonia sp. H37 was employed as a biocatalyst for preparing enantiopure (S)-styrene oxide derivatives.

Effect of the Interaction between Seaweed Intake and LPL Polymorphisms on Metabolic Syndrome in Middle-Aged Korean Adults.

This study aimed to examine the effect of the interaction between seaweed (laver, kelp, and sea mustard) intake and lipoprotein lipase gene (LPL) rs17482735 genotypes on the incidence of metabolic syndrome (MetS). The Korean Genome and Epidemiology Study (KoGES) data of Korean adults aged 40-69 years were used in this study. Information on seaweed intake was obtained from the food frequency questionnaire. To investigate the interaction between seaweed intake and LPL rs17482735 genotypes on the incidence of MetS, multivariable Cox proportional hazard models were used after adjusting for confounding variables. There was no significant association in women, but men with TG and TT genotypes of rs17482753 had lower incidence of MetS (HR 0.83, 95% CI 0.71-0.95, p-value = 0.01), low HDL-cholesterol levels (HR 0.81, 95% CI 0.69-0.95, p-value = 0.01), high triglyceride levels (HR 0.83, 95% CI 0.70-0.99, p-value = 0.0471), and high blood pressure (HR 0.79, 95% CI 0.67-0.93, p-value = 0.004). Furthermore, the incidence of MetS was lower in men with the highest laver and total seaweed intake and TG and TT genotypes of rs17482735 (HR 0.60, 95% CI 0.43-0.84; HR 0.57, 95% CI 0.41-0.79, respectively). High seaweed intake was negatively associated with MetS, suggesting that LPL genetic variations, particularly in men, may be helpful in preventing MetS. These results demonstrate that seaweed intake considering LPL genotypes may be beneficial for preventing and treating MetS.

Seaweed intake modulates the association between VIPR2 variants and the incidence of metabolic syndrome in middle-aged Koreans.

Vasoactive intrinsic peptide receptor (VIPR2), a circadian gene, is involved in metabolic homeostasis and metabolic syndrome (MetS). Seaweeds contain polysaccharides that regulate metabolic homeostasis, possibly by altering the effects of VIPR2 variants. We examined the relationship between VIPR2 expression and the incidence of MetS based on seaweed consumption. This study included 4979 Koreans aged ≥40 years using data from the Ansan-Ansung cohort of the Korean Genome and Epidemiology Study. The total seaweeds included were laver, kelp, and sea mustard. A multivariable Cox proportional hazards model was used to analyze the interactions between the VIPR2 rs6950857 genotype associated with MetS incidence and seaweed intake after adjusting for covariates such as region. A total of 2134 patients with MetS were followed for an average of 8.9 years. In men with the GG genotype of rs6950857, the highest quintile of seaweed consumption was associated with a decreased incidence of MetS compared with that of the lowest quintile (hazard ratio, 0.78; 95% confidence interval, 0.62-0.98). We identified a unique association between the rs6950857 genotype, seaweed intake, and MetS. These findings highlight the importance of VIPR2 and the regulatory role of seaweed consumption in MetS incidence.

Standardized extract of Glehnia Littoralis abrogates memory impairment and neuroinflammation by regulation of CREB/BDNF and NF-κB/MAPK signaling in scopolamine-induced amnesic mice model.

Mild cognitive impairment is a typical symptom of early Alzheimer's disease (AD). Glehnia littoralis (G. littoralis), a medicinal halophyte plant commonly used to treat strokes, has been shown to possess some therapeutic qualities. In this study, we investigated the neuroprotective and anti-neuroinflammatory effects of a 50% ethanol extract of G. littoralis (GLE) on lipopolysccharide (LPS)-stimulated BV-2 cells and scopolamine-induced amnesic mice. In the in vitro study, GLE treatment (100, 200, and 400 µg/mL) markedly attenuated the translocation of NF-κB to the nucleus concomitantly with the significant mitigation of the LPS-induced production of inflammatory mediators, including NO, iNOS, COX-2, IL-6, and TNF-α. In addition, the GLE treatment suppressed the phosphorylation of MAPK signaling in the LPS-stimulated BV-2 cells. In the in vivo study, mice were orally administered with the GLE (50, 100, and 200 mg/kg) for 14 days, and cognitive loss was induced via the intraperitoneal injection of scopolamine (1 mg/kg) from 8 to 14 days. We found that GLE treatment ameliorated memory impairment and simultaneously improved memory function in the scopolamine-induced amnesic mice. Correspondingly, GLE treatment significantly decreased the AChE level and upregulated the protein expression of neuroprotective markers, such as BDNF and CREB, as well as Nrf2/HO-1 and decreased the levels of iNOS and COX-2 in the hippocampus and cortex. Furthermore, GLE treatment attenuated the increased phosphorylation of NF-κB/MAPK signaling in the hippocampus and cortex. These results suggest that GLE has a potential neuroprotective activity that may ameliorate learning and memory impairment by regulating AChE activity, promoting CREB/BDNF signaling, and inhibiting NF-κB/MAPK signaling and neuroinflammation.

DNA barcoding of brackish and marine water fishes and shellfishes of Sundarbans, the world's largest mangrove ecosystem.

The present study aims to apply a DNA barcoding tool through amplifying two mitochondrial candidate genes i.e., COI and 16S rRNA for accurate identification of fish, aquatic molluscs and crustaceans of Sundarbans mangrove wetland, to build a reference library of fish and shellfishes of this unique ecosystems. A total of 185 mitochondrial COI barcode sequences and 59 partial sequences of the 16S rRNA gene were obtained from 120 genera, 65 families and 21 orders of fish, crustaceans and molluscs. The collected samples were first identified by examining morphometric characteristics and then assessed by DNA barcoding. The COI and 16S rRNA sequences of fishes and crustaceans were clearly discriminated among genera in their phylogenies. The average Kimura two-parameter (K2P) distances of COI barcode sequences within species, genera, and families of fishes are 1.57±0.06%, 15.16±0.23%, and 17.79±0.02%, respectively, and for 16S rRNA sequences, these values are 1.74±.8%, 0.97±.8%, and 4.29±1.3%, respectively. The minimum and maximum K2P distance based divergences in COI sequences of fishes are 0.19% and 36.27%, respectively. In crustaceans, the K2P distances within genera, families, and orders are 1.4±0.03%, 17.73±0.15%, and 22.81±0.02%, respectively and the minimum and maximum divergences are 0.2% and 33.93%, respectively. Additionally, the present study resolves the misidentification of the mud crab species of the Sundarbans as Scylla olivacea which was previously stated as Scylla serrata. In case of molluscs, values of interspecific divergence ranges from 17.43% to 66.3% in the barcoded species. The present study describes the development of a molecular and morphometric cross-referenced inventory of fish and shellfish of the Sundarbans. This inventory will be useful in future biodiversity studies and in forming future conservation plan.

Zooplankton diversity monitoring strategy for the urban coastal region using metabarcoding analysis.

Marine ecosystems in urban coastal areas are exposed to many risks due to human activity. Thus, long-term and continuous monitoring of zooplankton diversity is necessary. High-throughput DNA metabarcoding has gained recognition as an efficient and highly sensitive approach to accurately describing the species diversity of marine zooplankton assemblages. In this study, we collected 30 zooplankton samples at about 2-week intervals for 1 year. Zooplankton diversity showing a typical four season pattern. Of the "total" and "common" zooplankton, we assigned 267 and 64 taxa. The cluster structure and seasonal diversity pattern were rough when only the "common" zooplankton was used. Our study examined how to maximize the benefits of metabarcoding for monitoring zooplankton diversity in urban coastal areas. The results suggest that to take full advantage of metabarcoding when monitoring a zooplankton community, it is necessary to carefully investigate potential ecosystem threats (non-indigenous species) through sufficient curation rather than disregarding low-abundance operational taxonomic units.

Nucleotide sequencing of the HoxA gene cluster using Gorilla fosmid clones.

We sequenced the western gorilla (Gorilla gorilla) HoxA cluster region using seven fosmid clones, and found that the total tiling path sequence was 214,185 bp from the 5' non-genic region of HoxA1 to the 3' non-genic region of Evx1. We compared the nucleotide sequence with the gorilla genome sequence in the NCBI database, and the overall proportion of nucleotide difference was estimated to be 0.0005-0.0007. These estimates are lower than overall genomic polymorphism in gorillas.

DNA barcoding of coral reef fishes from Chuuk State, Micronesia.

The fish diversity of Chuuk Micronesia is currently under threat due to rapid changes in the coral reef ecosystem. Thus, accurate fish identification using DNA barcodes is fundamental for exploring species biodiversity and resource protection. In this study, we analyzed 162 fish mitochondrial DNA cytochrome c oxidase I (COI) barcodes from Chuuk Micronesia. Consequently, we identified 95 species from 53 genera in 26 families and seven orders. The average Kimura 2-parameter genetic distances within species, genera, families, and orders were calculated as 0.17%, 11.78%, 15.63%, and 21.90%, respectively. Also, we have utilized DNA barcodes to perform genetic divergence and phylogenetic analysis of families recognized as dominant groups in Chuuk State. Our findings confirm that DNA barcodes using COI are an effective approach in identifying coral reef fish species. We anticipate that the results of this study will provide baseline data for the protection of coral reef fish biodiversity at Chuuk Micronesia.

Effects of Balneotherapy in Jeju Magma-Seawater on Knee Osteoarthritis Model.

Balneotherapy is a common non-pharmacological treatment for osteoarthritis (OA), however, the efficacy is controversial in knee OA. Jeju magma-seawater (JMS) has high contents of various minerals, which has anti-inflammatory and antioxidant properties via an oral route. Thus, we examined the effects of JMS bathing on knee OA and the combination effects with diclofenac sodium as an anti-inflammatory drug. Knee OA was induced by transection of the anterior cruciate ligament and the partial meniscectomy in rat. The rats were administered subcutaneously saline or diclofenac sodium in saline, followed by bathing in thermal distilled water or JMS for 8 weeks. The model represented the characteristic changes of the cartilage degradation, osteophyte formation and synovial inflammation, and the relevant symptoms of the joint swelling and stiffness. However, the JMS bathing reduced the joint thickness and improved the mobility. It also contributed to a well-preserved tissue supported by increases in bone mineral density of the joint and decreases in Mankin scores in the cartilages. The effects involved anti-inflammation, chondroprotection, anti-apoptosis, and chondrogenesis. Overall, the JMS bathing in combination with diclofenac sodium showed a similar trend associated with synergic effects. It suggests that JMS bathing can be promising for a clinical use in knee OA.

Effect of Peat Intervention on Pain and Gait in Patients with Knee Osteoarthritis: A Prospective, Double-Blind, Randomized, Controlled Study.

METHODS: Knee osteoarthritis patients with Visual Analog Scale (VAS) of 3 or more and Kellgren-Lawrence osteoarthritis grades 1 to 3 were included. Patients with history of intraarticular injection treatment were excluded. Forty-one participants were randomly allocated to the peat intervention group (n = 22) or the hot-pack-only control group (n = 19). Peat and hot pack were applied to both knees of each group of patients. Each intervention session lasted 20 minutes, and eight sessions were completed over five days. VAS, serum cartilage oligomeric matrix protein (COMP), and gait parameters were evaluated before and after the whole interventions. RESULTS: VAS in the peat group decreased from 6.000 to 3.409 after intervention (p < 0.001) and also decreased in the control group from 5.737 to 4.421 (p < 0.001). VAS score reduction between two periods was greater in the peat group than that in the control group (p < 0.001). There was no significant difference in the serum COMP level in either intergroup or intragroup analysis. In gait analysis, the gait velocity of the peat group increased from 0.781 m/s to 0.873 m/s after intervention (p=0.002), while it decreased in the control group. The knee varus/valgus range of motion during gaits was reduced from 11.455° to 8.439° after intervention in the peat group (p=0.006). CONCLUSIONS: This study showed that peat can be considered as a therapeutic option for pain relief of knee osteoarthritis patients. The reduction in knee joint varus/valgus range of motion and the increase in gait velocity after peat intervention were also identified through this research, which is the first to analyze the effects of peat on gait.

Molecular cloning and characterization of a novel cold-active beta-1,4-D-mannanase from the Antarctic springtail, Cryptopygus antarcticus.

A cDNA encoding a beta-1,4-d-mannanase (CaMan) was identified among the expressed sequence tags (ESTs) of the Antarctic springtail, Cryptopygus antarcticus. The open reading frame consisted of 1149 bp encoding 382 amino acids with a putative signal peptide. Amino acid sequence comparison with other mannanases indicated that CaMan likely belongs to subfamily 10 of the glycoside hydrolase family 5, together with mollusc beta-mannanases. CaMan shows typical features of a cold-active enzyme: it has a high frequency of polar residues such as Asn, Gln, and Ser, and a low frequency of hydrophobic residues as well as a low ratio of Arg/(Arg+Lys) compared to the mesophilic beta-mannanases. When CaMan was fused with the thioredoxin gene in pET-32a(+), expressed in E. coli Rosetta-gami (DE3), and purified after thrombin treatment, catalytically active enzyme was obtained. CaMan has high specific activity (416.3 U/mg) toward locust bean gum at an optimal temperature of 30 degrees C and an optimal pH of 3.5. Its optimal temperature is the lowest among those of the known mannanases and the optimal pH is also the lowest except those of fungi. Even at 0-5 degrees C, this enzyme retained 20-40% of its maximum activity. Divalent metal ions such as Ca(2+), Mg(2+), Cu(2+), and Zn(2+) enhanced the enzyme activity, but Mn(2+), Hg(2+), and Ag(+) inhibited activity. This study represents the first record of a beta-mannanase from an arthropod and provides a new source of carbohydrate hydrolysis enzyme with novel characteristics.

Bathing effects of east saline groundwater concentrates on allergic (atopic) dermatitis-like skin lesions induced by 2,4-dinitrochlorobenzene in hairless mice.

In the present study, it was evaluated whether east saline groundwater concentration solution (ESGWc) exerted a favorable inhibitory effect on 2,4-dinitrochlorobenzene (DNCB)-induced allergic/atopic-like dermatitis (AD). AD was induced and boosted by sensitization with DNCB via topical application on the dorsal back skins. Mice with DNCB-induced AD were bathed in 100-, 200- and 400-fold diluted ESGWc. After 6 weeks bathing, changes to body weight, clinical skin severity scores, scratching behavior, serum total immunoglobulin (Ig)E levels, submandibular lymph node and spleen weights, splenic cytokine levels, skin cytokine mRNA expressions, antioxidant defense systems and superoxide anion productions were recorded to determine the effects of bathing on the histopathology of dorsal back skin tissues. All DNCB-induced mice demonstrated that the induction of AD through IgE-mediated hypersensitivities, oxidative stresses, activation of MMP and apoptosis of keratinocytes resulted in no significant differences in body weight between the different groups at each time point following initial sensitization. However, markers of DNCB-induced AD were significantly inhibited (P<0.05) in a concentration-dependent manner following bathing in all concentrations of ESGWc. The results obtained in the present study suggest that bathing in ESGWc may have favorable protective effects against DNCB-induced AD due to favorable systemic and local immunomodulatory effects, active cytoprotective anti-apoptotic effects, inhibitory effects of matrix metalloproteinase activity, and anti-inflammatory and antioxidative effects.

Human Endogenous Retrovirus (HERV)-R family in primates: Chromosomal location, gene expression, and evolution.

Hitherto, full-length endogenous retrovirus (HERV)-R has been located at human chromosome 7q11.2, and mRNA and envelope proteins have been detected in placenta and a variety of other cell types. In the present study, using a probe derived from the gorilla fosmid library, we detected the paralogous locus (7q31.3) of the HERV-R env gene in human chromosome 7q11.2, and also determined the chromosomal location in apes and Old World monkeys. The HERV-R gene was not detected in New World monkeys or prosimians with FISH and PCR analyses. We determined the sequences of the HERV-R env genes obtained from the genomic DNA of primates using PCR and sequencing tools. Except for a HERV-R env sequence derived from gorilla DNA, the functional domains of putative envelope proteins are conserved, suggesting that those domains could have a functional capacity in the primate genome. In addition, we investigated the env gene expression of HERV-R in various human tissues and cancer cells. An RT-PCR approach indicated that the env gene was expressed in several human tissues (brain, prostate, testis, kidney, placenta, thymus, and uterus) and cancer cells (RT4, BT-474, MCF7, OVCAR-3, LOX-IMVI, and AZ521). Taken together, our data could be of great use for understanding the evolutionary dynamics of HERV-R through primate radiation as well as the implications of its functional role in human tissues and cancers cells.

No Distinction of Orthology/Paralogy between Human and Chimpanzee Rh Blood Group Genes.

On human (Homo sapiens) chromosome 1, there is a tandem duplication encompassing Rh blood group genes (Hosa_RHD and Hosa_RHCE). This duplication occurred in the common ancestor of humans, chimpanzees (Pan troglodytes), and gorillas, after splitting from their common ancestor with orangutans. Although several studies have been conducted on ape Rh blood group genes, the clear genome structures of the gene clusters remain unknown. Here, we determined the genome structure of the gene cluster of chimpanzee Rh genes by sequencing five BAC (Bacterial Artificial Chromosome) clones derived from chimpanzees. We characterized three complete loci (Patr_RHα, Patr_RHß, and Patr_RHγ). In the Patr_RHß locus, a short version of the gene, which lacked the middle part containing exons 4-8, was observed. The Patr_RHα and Patr_RHß genes were located on the locations corresponding to Hosa_RHD and Hosa_RHCE, respectively, and Patr_RHγ was in the immediate vicinity of Patr_RHß. Sequence comparisons revealed high sequence similarity between Patr_RHß and Hosa_RHCE, while the chimpanzee Rh gene closest to Hosa_RHD was not Patr_RHα but rather Patr_RHγ. The results suggest that rearrangements and gene conversions frequently occurred between these genes and that the classic orthology/paralogy dichotomy no longer holds between human and chimpanzee Rh blood group genes.

Complete mitochondrial genome sequence of Heliocidaris crassispina (Camarodonta, Echinometridae).

The whole mitochondrial genome sequence of sea urchin Heliocidaris crassispina of the family Echinometridae is determined for the first time in this study. The circular mitogenome (15,702 bp) consists of typical Camarodonta gene order and its components including 2 rRNA, 22 tRNA, 13 protein-coding genes and a control region. Phylogenetic analysis based on the 13 concatenated protein-coding gene sequences shows that H. crassispina is closer to the species of Strongylocentrotidae than Parechinidae, but the separation between H. crassispina and the Strongylocentrotid species occurred early in their evolution. The complete mitochondrial genome presented in this study is useful for inferring the phylogenetic relationship among the families of Echinidea sea urchins.

Complete mitochondrial genome of the mottled skate: Raja pulchra (Rajiformes, Rajidae).

The complete sequence of mitochondrial DNA of a mottled skate, Raja pulchra was sequenced as being circular molecules of 16,907 bp including 2 rRNA, 22 tRNA, 13 protein-coding genes (PCGs), and an AT-rich control region. The organization of the PCGs is the same as those found in other Rajidae species. The nucleotide of L-strand is composed of 29.8% A, 28.0% C, 27.9% T, and 14.3% G with a bias toward A + T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of [Formula: see text] which has a reduced DHU arm. This mitogenome will provide essential information for better phylogenetic resolution and precision of the family Rajidae and the genus Raja as well as for establishment of a fish stock recovery plan of the species.

Complete mitochondrial genome of the Kwangtung skate: Dipturus kwangtungensis (Rajiformes, Rajidae).

The complete sequence of mitochondrial DNA of a Kwangtung skate, Dipturus kwangtungensis, was determined as being circular molecules of 16,912 bp including 2 rRNA, 22 tRNA, 13 protein coding genes (PCGs) and a control region. The arrangement of the PCGs is the same as that found in other Rajidae species. The nucleotide of L-strand which encodes most of the proteins is composed of 30.2% A, 27.4% C, 28.2% T and 14.2% G with a bias toward A+T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of tRNA(Ser)AGY, which has a reduced DHU arm. This mitogenome is the first report for a species of the genus Dipturus, which will become an important source of information on the phylogenetic relationship and the evolution of the genus Dipturus within the family Rajidae.