Comparative risk of osteoporotic fracture among patients with rheumatoid arthritis receiving TNF inhibitors versus other biologics: a cohort study.

In this population-based cohort study on comparative osteoporotic fracture risks between different biologic disease-modifying drugs among patients with rheumatoid arthritis (RA), we did not find a significant difference in the risk of osteoporotic fractures between RA patients receiving TNF inhibitors versus abatacept or tocilizumab. INTRODUCTION: We aimed to investigate the comparative risk of osteoporotic fractures between rheumatoid arthritis (RA) patients who initiated TNF inhibitors (TNFis) versus abatacept or tocilizumab. METHODS: Using the Korea National Health Insurance Service datasets from 2002 to 2016, RA patients who initiated TNFis, abatacept, or tocilizumab were identified. The primary outcome was a composite end point of non-vertebral fractures and hospitalized vertebral fractures; secondary outcomes were two components of the primary outcome and fractures occurring at the humerus/forearm. Propensity score (PS) matching with a variable ratio up to 10 TNFi initiators per 1 comparator drug initiator was used to adjust for > 50 baseline confounders. We estimated hazard ratios (HRs) and 95% confidence interval (CI) of fractures comparing TNFi initiators to abatacept and to tocilizumab by Cox proportional hazard models stratified by a matching ratio. RESULTS: After PS-matching, 2307 TNFi initiators PS-matched on 588 abatacept initiators, and 2462 TNFi initiators on 640 tocilizumab initiators were included. A total of 77 fractures occurred during a mean follow-up of 454 days among TNFi and abatacept initiators and 83 fractures during 461 days among TNFi and tocilizumab initiators. The PS-matched HR (95% CI) was 0.91 (0.48-1.71) comparing TNFi versus abatacept initiators, and 1.00 (0.55-1.83) comparing TNFi versus tocilizumab initiators. Analysis on vertebral and non-vertebral fractures showed similar results. CONCLUSIONS: In this nationally representative cohort, we did not find a significant difference in the risk of fractures between TNFi initiators versus abatacept or tocilizumab among RA patients.

Disc degeneration induces a mechano-sensitization of disc afferent nerve fibers that associates with low back pain.

OBJECTIVE: We aimed to investigate mechano-sensitivity at the afferent nerve fibers projecting to degenerated intervertebral disc (IVD) and nociceptive behaviour in a rat model of low back pain (LBP). DESIGN: Animal model with LBP was established by lumbar 4/5 IVD puncture and nucleus pulposus aspiration. In vivo single nerve recordings (n = 121) were introduced to measure discharge frequency at the afferent nerve fiber innervating the IVD during mechanical stimulations (von Frey filament or intradiscal pressure). Nerve growth factor (NGF) expression levels in the IVD (n = 20) were assessed by Western blot. LBP-related behaviour (n = 22) was assessed by measuring changes in rearing, mechanical paw-withdrawal threshold, and dynamic weight bearing in a freely walking rat. Inhibitory effect of morphine on the neuronal excitability (n = 19) and painful behaviour (n = 28) was also assessed. RESULTS: Compared to those with sham or naïve IVD, animal group with degenerated IVD displayed the sensitized neuronal responses and painful behaviour, with hyperexcitability of the afferent nerve fibers in any range of mechanical stimulations (von Frey filament stimulation; 1, 2, and 26 g; intradiscal pressure, 1,500-3,000 mm Hg), strong upregulation of NGF (200-250 % increase), and LBP-like behaviour such as failure of rearing, front limbs-dependent walking pattern, and hypersensitivity in hind-paws. However, the neuronal hyperexcitability and pain behaviour were attenuated after local (30 µM) or systemic (3 mg kg-1) morphine administration. CONCLUSIONS: Our study suggests that enhanced mechano-sensitivity at the afferent nerve fiber innervating degenerated IVD is deeply correlated with LBP development, which supports the hypothesis that hyperexcited responses at the nerve fibers represent a decisive source of LBP.

Short communication: Physicochemical and antioxidant properties of Cheddar-type cheese fortified with Inula britannica extract.

Cheddar-type cheese was fortified with the antioxidant Inula britannica flower extract (IBE). Cheddar-type cheeses manufactured with varying concentrations of IBE (0, 0.25, 0.5, 0.75, and 1% wt/vol) were analyzed during storage at 4°C, 0, 1, 2, and 3 wk after production. Higher IBE concentrations resulted in higher protein and ash contents, with a concomitant decrease in pH, total solid, and fat content relative to the unfortified control cheese. The total phenolic content also increased with IBE concentration, but decreased over longer storage periods. The antioxidant activities of the cheeses, determined as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and ferric thiocyanate assay results, increased proportionally to the total phenolic content. The highest antioxidant effect was observed in the 1% IBE-fortified cheese, showing 79 and 86% antioxidant effects in the DPPH and ferric thiocyanate assays, respectively. At the 1-wk time point, the 5 cheese preparations underwent sensory evaluation for odor, taste, texture, color, and overall quality, determined using a descriptive analysis by a trained panel (n=20). The addition of IBE resulted in some increases in extract odor and taste. Overall, IBE showed good potential as an antioxidant supplement for dairy products.

A combined variation of the right urogenital veins and bilaterally renal arteries.

Variation in urogenital vessels is of interest to clinicians as well as anatomists since it has complex steps of urogenital development. We found 2 right and 3 left renal arteries, double right renal veins, the right testicular artery arisen from the right main renal artery, and the right testicular vein as a tributary of an additional right renal vein in a 57-year-old Korean male cadaver, whose cause of death was 'unknown'. The multiple vascular variations near the renal hilum are detectable in seemingly normal individuals and a deeper understanding of the complicated urogenital vasculature might be very important with its embryogenesis.

First Report of Clover yellow vein virus on White Clover (Trifolium repens) in South Korea.

White clover (Trifolium repens L.) is a herbaceous, perennial plant that has become one of the most widely distributed legumes in the world. It is extensively used in grass-legume pastures, but also has the potential to invade agricultural lands and natural ecosystems. White clover is a well-known natural host for Alfalfa mosaic virus (AMV), Clover yellow vein virus (ClYVV), Soybean dwarf virus (SbDV), Beet western virus (BWYV), Tomato spotted wilt virus (TSWV), Zucchini yellow mosaic virus (ZYMV), etc (1). In July 2013, during a survey to determine the presence of different viruses infecting weed plants in South Korea, three white clover leaf samples showing yellow mosaic symptoms were collected from Taean County, South Chungcheong Do Province, South Korea. In order to identify the infecting virus, total RNA from three leaf samples was extracted using the Tri-reagent (MRC Reagent, Inc., OH) as described by the manufacturer, and was applied to the large-scale oligonucleotide (LSON) chip (3), wherein probes specific to a ClYVV isolate produced a positive reaction. All three samples tested were positive for ClYVV. To confirm this result, ClYVV-specific primers were designed using the sequences of four ClYVV isolates from NCBI (GenBank Accession Nos. AF185959, AF203536, DQ333346, and NC003536). Total RNA was extracted from symptomatic white clover samples using Easy-Spin Total RNA Extraction Kit (iNtRon, Daejeon, Korea) and used as template for RT-PCR. The positive control RNA was used from ClYVV GM isolate (KF975894) and negative control RNA used symptomless white clover plants. The ClYVV coat protein (CP) gene was amplified by RT-PCR using the specific primer pairs ClYVV-CP-F / ClYVV-CP-R (5'-CAAGAGCAGCACGATGAG-3' and 5'-CTCGCTCTATAAAGATCAGAT-3'). DNA fragments of the expected size (1,042 bp) were obtained from the white clover Korea isolate (AB930132), and the PCR product was cloned into a T&A cloning vector (RBC Bioscience, Taipei, Taiwan) and sequenced directly in both directions. BLAST analyses of the nucleotide sequence CP gene fragments revealed the highest identity with 98% with other ClYVV isolates (AF203536). To determine the experimental host range of the ClYVV Korea isolate, we inoculated five species (Chenopodium amaranticolor, C. quinoa, Nicotiana clevelandii, N. benthamiana, and Trifolium repens) in three families using this isolate. All test plants were mechanically inoculated with 0.1 M phosphate buffered saline (Takara, Tokyo, Japan). Each test plant was inoculated nine times and grown in a greenhouse maintained at 27 to 33°C. Necrotic local lesions were produced on inoculated leaves of C. amaranticolor, C. quinoa, and N. clevelandii 4 to 6 days post-inoculation. After 10 to 14 days, C. amaranticolor and C. quinoa showed systemic chlorotic spot symptoms, and N. clevelandii, N. benthamiana, and T. repens showed chlorotic spot, mild mosaic, and mosaic in the upper leaves, respectively. Up to now, in South Korea, ClYVV has been detected in gladiolus (Gladiolus gandavensis) (3) and soybean (Glycine max) (4). ClYVV can be easily transmitted by insect, aphid, or mechanical inoculation and has a host range including tobacco, soybean, etc. The presence of ClYVV could become an important threat to crop production in South Korea. To our knowledge, this is the first report of a ClYVV infection of the white clover plant in South Korea. References: (1) B. L. Denny and P. L. Guy. Australas. Plant Pathol. 38:270, 2009. (2) M. Nam et al. Plant Pathol. J. 30:51, 2014. (3) I. S. Park et al. Korean J. Plant Pathol. 14:74, 1998. (4) J. C. Shin et al. Plant Dis. 98:1283, 2014.

Complete genome sequence data of Leuconostoc mesenteroides KNU-2 and Weissella hellenica MBEL1842 isolated from kimchi.

Kimchi, a traditional Korean fermented food, contains many lactic acid bacteria. Leuconostoc mesenteroides KNU-2 strain with low-temperature tolerance and Weissella hellenica MBEL1842 with antibacterial activity were isolated from kimchi. The genomes of L. mesenteroides KNU-2 and W. hellenica MBEL1842 are composed of one circular chromosomal genome of 1,973,419 bp (37.9% G+C content) and 1,887,056 bp (37.9% G+C content), as well as four and one plasmids, respectively, The sequence data of the strains were deposited in GenBank under the accession numbers CP089782 (L. mesenteroides KNU-2) and CP086020 (W. hellenica MBEL1842).

High Estimated 24-Hour Urinary Sodium Excretion Is Related to Symptomatic Knee Osteoarthritis: A Nationwide Cross-Sectional Population-Based Study.

OBJECTIVES: High salt intake results in various harmful effects on human health including hypertension, cardiovascular disease, and reduced bone density. Despite this, there are very few studies in the literature that have investigated the association between sodium intake and osteoarthritis (OA). Therefore, we aimed to explore these associations in a Korean population. METHODS: This study used cross-sectional data from adult subjects aged 50-75 years from two consecutive periods of the Korean National Health and Nutrition Examination Survey V-VII (2010-2011 and 2014-2016). The estimated 24-hour urinary sodium excretion (24HUNa) was used as a surrogate marker of salt intake. In the 2010-2011 dataset, knee OA (KOA) was defined as the presence of the radiographic features of OA and knee pain. The association between KOA and salt intake was analysed using univariable and multivariable logistic regression methods. For the sensitivity analysis, the same procedures were conducted on subjects with self-reported OA (SR-OA) with knee pain in the 2010-2011 dataset and any site SR-OA in the 2014-2016 dataset. RESULTS: Subjects with KOA had significantly lower energy intake, but higher 24HUNa than those without KOA. The restricted cubic spline plots demonstrated a J-shaped distribution between 24HUNa and prevalent KOA. When 24HUNa was stratified into five groups (<2, 2-3, 3-4, 4-5 and ≥5 g/day), subjects with high sodium intake (≥5 g/day) had a higher risk of KOA (odds ratio [OR] = 1.64, 95% confidence interval [CI] 1.03-2.62) compared to the reference group (3-4 g/day) after adjusting for covariates. The sensitivity analysis based on SR-OA with knee pain showed that high sodium intake was also significantly associated with increased prevalence of OA (OR = 1.84, 95% CI 1.10-3.10) compared with the reference group. Regarding SR-OA at any site in the 2014-2016 dataset, estimated 24HUNa showed a significantly positive association with the presence of SR-OA after adjusting for potential confounders. CONCLUSIONS: This nationwide Korean representative study showed a significant association between symptomatic KOA and high sodium intake (≥5 g/day). Avoidance of a diet high in salt might be beneficial as a non-pharmacologic therapy for OA.

Population attributable fraction of infection-related cancers in Korea.

BACKGROUND: A number of infectious agents have been classified as human carcinogens. The purpose of the current study was to provide an evidence-based assessment of the burden of infection-related cancers in the Korean population. MATERIALS AND METHODS: The population attributable fraction was calculated using infection prevalence data from 1990 or earlier, relative risk estimates from meta-analyses using mainly Korean studies and national data on cancer incidence and mortality for the year 2007. RESULTS: The fractions of all cancers attributable to infection were 25.1% and 16.8% for cancer incidence in men and women, and 25.8% and 22.7% of cancer mortality in men and women, respectively. Among infection-related cancers, Helicobacter pylori was responsible for 56.5% of cases and 45.1% of deaths, followed by hepatitis B virus (HBV) (23.9% of cases and 37.5% of deaths) and human papillomavirus (HPV) (11.3% of cases and 6% of deaths) and then by hepatitis C virus (HCV) (6% of cases and 9% of deaths). Over 97% of infection-related cancers were attributable to infection with H. pylori, HBV, HCV and HPV. CONCLUSION: Up to one-quarter of cancer cases and deaths would be preventable through appropriate control of infectious agents in Korea.

Application of the combined use of ultrasonic homogenization and electro-spraying in the formation of nano carrier systems.

Chitosan-coated nano-liposomes containing etofenprox were prepared by ultrasonic homogenization (UH) and a combined use of UH and electro-spraying. The physicochemical properties of the resulting samples were examined and compared. The two methods yielded similar values and tendencies, except for encapsulation efficiency that differed by an average of 15%. In the coating process, as the chitosan concentration increased (0.1-0.5%, w/v) and the degree of deacetylation increased (chitosans A, B and C), the surface charge of the nano carrier likewise increased and carrier size distribution was altered. The encapsulation efficiency as measured by gas chromatography decreased slightly with the increasing chitosan concentration (0.1-0.5%, w/v). The results indicate that diverse preparation conditions could affect the physicochemical properties of the resulting nano carrier systems.

Remodelling of nasal mucosa in mild and severe persistent allergic rhinitis with special reference to the distribution of collagen, proteoglycans, and lymphatic vessels.

BACKGROUND: Small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen, and lymphangiogenesis are involved in tissue remodelling of various organs with inflammatory diseases. OBJECTIVE: We determined the expression level and the distribution pattern of small leucine-rich repeat proteoglycans (decorin, biglycan, and lumican), collagen and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa. METHODS: The distribution pattern of collagen, proteoglycans, and lymphatic vessels in healthy, mild, and severe persistent allergic nasal mucosa was evaluated by the van Gieson staining, immunohistochemistry, RT-PCR, and Western blotting. Quantitative analyses of collagen deposition were calculated as the median of the total percentage area in the tissue specimen. For the evaluation of proteoglycans, the percentage area stained and median optical density were measured for each image. Lymphatic vessels were identified by D2-40 antibody and calculated using the lymphatic vessel density and endothelial length density in tissue specimens. The expression of MMP 2 and 9, TIMP1 and 2 was evaluated with RT-PCR and Western blotting. RESULTS: In mild and severe persistent allergic nasal mucosa, compared with healthy nasal mucosa, collagen showed more intense staining in the superficial and submucosal layer. In healthy and allergic nasal mucosa, decorin was lightly stained without significant differences in the percentage area and optical density of staining. However, lumican and biglycan showed strong immunoreactivity in mild and severe persistent allergic nasal mucosa, which was verified by Western blotting. The number and endothelial length density of lymphatic vessels were increased in mild and severe persistent allergic nasal mucosa compared with healthy nasal mucosa. The expression of MMP 9 was increased in severe persistent allergic rhinitis. CONCLUSION AND CLINICAL RELEVANCE: These results suggest that the altered distribution pattern of collagen, proteoglycans, and lymphatic vessels could potentially modulate the remodelling of nasal mucosa in mild and severe persistent allergic nasal mucosa.

Arterial blood pressure vs intracranial pressure in normal pressure hydrocephalus.

OBJECTIVE: To characterize the association between arterial blood pressure (ABP) and intracranial pressure (ICP) in idiopathic normal pressure hydrocephalus (iNPH) patients, and its impact on outcome of shunt surgery. MATERIALS AND METHODS: We analyzed all 35 iNPH patients whose ABP and ICP were recorded simultaneously during 6 years (2002-2007). The static and pulsatile pressures were averaged over consecutive 6-s intervals; the moving correlations between ICP and ABP (static and pulsatile) were determined during consecutive 4-min periods to explore time-related variations. RESULTS: Neither static nor pulsatile ABP were altered in iNPH shunt responders. Elevated pulsatile ICP, but normal static ICP, was seen in responders. The time-varying correlations of static and of pulsatile pressures were generally low, and did not differ between shunt responders/non-responders. CONCLUSIONS: In iNPH shunt responders, static or pulsatile ABP were not altered and only pulsatile ICP was elevated.

Karyotype conservation and difference in DNA amount in anguilloid fishes.

The two Pacific anguilloid sishes Anguilla japonica and Astroconger myriaster, belonging to the different families, appear to have identical chromosome numbers (2n = 38) and karyotypes, including one pair of conspicuous heteromorphic chromosomes in females. Cytophotometric measurements, however, indicate a considerable difference in DNA content between the two species.

Expression of the atf1+ gene is upregulated in fission yeast under nitrosative and nutritional stresses.

This work was designed to assess regulation of the atf1+ gene in the fission yeast Schizosaccharomyces pombe under nitrosative and nutritional stresses, using the atf1+-lacZ fusion gene and RT-PCR. Nitric oxide (NO)-generating sodium nitroprusside (SNP; 10 micromol/L) and nitrogen depletion significantly enhanced synthesis of beta-galactosidase from the atf1+-lacZ fusion gene in S. pombe Pap1-positive KP1 cells, but not in S. pombe Pap1-negative TP108-3C cells. SNP (10 micromol/L) and nitrogen depletion also caused a significant increase in atf1+ mRNA levels in Pap1-positive cells, but not in Pap1-negative cells. Depletion of glucose marginally increased synthesis of beta-galactosidase from the fusion gene in S. pombe Pap1-positive cells. Taken together, the S. pombe atf1+ gene is upregulated by nitrosative and nutritional stresses on a transcriptional level, possibly via the mediation of Pap1.

Genomic cloning of the Hsc71 gene in the hermaphroditic teleost Rivulus marmoratus and analysis of its expression in skeletal muscle: identification of a novel muscle-preferred regulatory element.

To further our understanding of the role of stress proteins in development as well as in adaptation of fish to adverse environmental conditions, we undertook molecular analyses of stress protein encoding genes from the hermaphroditic teleost Rivulus marmoratus. We isolated a genomic clone containing the Hsc71 gene (rm-hsc71m) and its upstream sequences. rm-Hsc71m is not induced by external stress, but is enriched in a tissue-specific manner during early development. In adult, the strongest expression appeared in skeletal muscle, whereas lower expression was seen in the gill, eye and brain. To understand the regulatory basis of high muscle expression of rm-hsc71m, transfection of R.marmoratus muscle tissue was performed using 5' deletion fragments containing the rm-hsc71m promoter driving EGFP expression. An upstream region from -2.7 to -1.9 kb was identified as a muscle-specific regulatory region. Within this region, we identified at least three sites with the novel sequence TGTnACA interacting with a fish muscle factor having an M(r) of 32 000. Our data indicate that rm-hsc71m expression in skeletal muscle is controlled by a muscle-specific regulatory element containing this novel motif.

Hepatocarcinogenicity of diethylnitrosamine to the self-fertilizing hermaphroditic fish Rivulus marmoratus (Teleostomi: Cyprinodontidae).

The larvae, 3 days post hatching, of self-fertilizing hermaphroditic fish Rivulus marmoratus were exposed to diethylnitrosamine (DENA) (CAS: 55-18-5; N-nitrosodiethylamine) at levels of 50-400 ppm for 2 hours. At 3-month intervals, the exposed fish were sampled until 9 months postcarcinogen treatment. Hepatomas were induced in 6- and 9- month groups of the 100-ppm-treated and 200-ppm-treated fish. An exposure of fish larvae to 400 ppm DENA also produced similar tumors on 3-, 6-, and 9-month groups. The tumor incidences were clearly dose dependent. These results offered the possibility of the use of R. marmoratus as a suitable model for experimental carcinogenesis.

Cyclic AMP-dependent expression of the Escherichia coli serC-aroA operon.

The Escherichia coli serC-aroA operon encodes biosynthetic enzymes for unrelated amino acid biosynthetic pathways leading to the synthesis of serine and the aromatic amino acids. A serC-aroA-lac translational fusion was constructed in the vector pMC1403. Synthesis of beta-galactosidase from the serC-aroA-lac fusion was found to be enhanced in the presence of lactose as the sole carbon source. This enhancement was not observed in strains containing a cya or crp mutant. However, the exogenous addition of cAMP greatly increased the beta-galactosidase synthesis in the cya mutant strain. The serC-aroA mRNA content, analyzed by a dot blot assay, also appeared to increase in the serC+ aroA+ cells after the exogenous addition of cAMP. These findings unambiguously indicate that the expression of the serC-aroA operon is positively controlled by cAMP.

Cloning, expression and regulation of Schizosaccharomyces pombe gene encoding thioltransferase.

The genomic DNA encoding thioltransferase was isolated from Schizosaccharomyces pombe using the polymerase chain reaction. The amplified DNA fragment was confirmed by Southern hybridization, completely digested with HindIII and BamHI, and then ligated into the yeast-Escherichia coli shuttle vector pRS316, which resulted in plasmid pEH1. The insert of plasmid pEH1 was transferred into the multi-copy vector YEp357 to generate plasmid pYEH1. The determined nucleotide sequence harbors an open reading frame consisting of four exons and three introns, which encodes a polypeptide of 101 amino acids with a molecular mass of 11261 Da. Thioltransferase activity was increased 1.6-fold in Saccharomyces cerevisiae containing plasmid pYEH1, and 1.8- and 2.7-fold in S. pombe containing plasmid pEH1 and pYEH1, respectively. The upstream sequence and the region encoding the N-terminal six amino acids were fused into promoterless beta-galactosidase gene of the shuttle vector YEp357R to generate the fusion plasmid pYEHR1. Synthesis of beta-galactosidase from the fusion plasmid was found to be enhanced by zinc and NO-generating S-nitroso-N-acetylpenicillamine.

Characterization and regulation of glutathione S-transferase gene from Schizosaccharomyces pombe.

A glutathione S-transferase (GST) gene has been cloned from Schizosaccharomyces pombe for the first time. The nucleotide sequence determined was found to contain 2030 base pairs including an open reading frame of 229 amino acids that would encode a protein of a molecular mass of 27017 Da. The cloned GST gene was expressed and was found to function in S. pombe, Saccharomyces cerevisiae, and Escherichia coli. The plasmid pGT207 encoding the S. pombe GST gene appeared to be able to accelerate the growth of a wild type S. pombe culture. In a culture of S. pombe containing plasmid pGT207, the growth was inhibited less by mercuric chloride than in a culture with vector alone. The 1088 bp region upstream from the GST gene as well as the region encoding the N-terminal 14 amino acids was transferred into the promoterless beta-galactosidase gene of plasmid YEp357R to yield the fusion plasmid pYSH2000. beta-Galactosidase synthesis was induced by cadmium chloride, mercuric chloride, hydrogen peroxide, and menadione. It was also induced by high temperature. These results suggest that the cloned S. pombe GST gene is involved in the oxidative stress response.

Can the shape of attractor forbid chaotic phase synchronization?

We address the question, which properties of a chaotic oscillator are crucial for its ability/inability to synchronize with external force or other similar oscillators. The decisive role is played by temporal coherency whereas the shape of the attractor is less important. We discuss the role of coordinate-dependent reparameterizations of time which preserve the attractor geometry but greatly influence the coherency. An appropriate reparameterization enables phase synchronization in coupled multiscroll attractors. In contrast, the ability to synchronize phases for nearly isochronous oscillators can be destroyed by a reparameterization which washes out the characteristic time scale.

The complete DNA sequence of the mitochondrial genome of the self-fertilizing fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) and the first description of duplication of a control region in fish.

We isolated Rivulus marmoratus mitochondrial DNA by long-polymerase chain reaction with conserved primers, and sequenced it with 36 sets of internal conserved primers, which were designed from the extensive sequence similarities of mitochondrial DNA from several fish species. The R. marmoratus mitochondrial DNA has 17,329 bp with a conserved structural organization compared to those of other fish. Rivulus marmoratus mitochondrial DNA also has two nearly identical control regions. The basic characteristics of the R. marmoratus mitochondrial genome are discussed.