Comparative Efficacy of Micro-Needle-Knife Therapy and Acupuncture in Acute Ankle Sprains: A Randomized Controlled Trial.

BACKGROUND Micro-needle knife (MNK) therapy releases the superficial fascia to alleviate pain and improve joint function in patients with acute ankle sprains (AAS). We aimed to evaluate the efficacy and safety of MNK therapy vs that of acupuncture. MATERIAL AND METHODS This blinded assessor, randomized controlled trial allocated 80 patients with AAS to 2 parallel groups in a 1: 1 ratio. The experimental group received MNK therapy; the control group underwent conventional acupuncture treatment at specified acupoints. Clinical efficacy differences between the 2 groups before (time-point 1 [TP1]) and after treatment (TP2) were evaluated using the visual analogue scale (VAS) and Kofoed ankle score. Safety records and evaluations of adverse events were documented. One-month follow-up after treatment (TP3) was conducted to assess the intervention scheme's reliability. RESULTS VAS and Kofoed ankle scores significantly improved in both groups. No patients dropped due to adverse events. At TP1, there were no significant differences between the 2 groups in terms of VAS and Kofoed scores (P>0.05). However, at TP2, efficacy of MNK therapy in releasing the superficial fascia was significantly superior to that of acupuncture treatment (P<0.001). At TP3, no significant differences in scores existed between the groups (P>0.05). CONCLUSIONS This study demonstrates that 6 sessions of MNK therapy to release the superficial fascia safely and effectively alleviated pain and enhanced ankle joint function in patients with AAS, surpassing the efficacy of conventional acupuncture treatment. Future studies should increase the sample size and introduce additional control groups to further validate the superior clinical efficacy of this intervention.

Severity of Intracranial Large Artery Disease Correlates With Cerebral Small Vessel Disease.

BACKGROUND: Small vessel disease (SVD) shares common vascular risk factors with large artery disease (LAD). However, little is known about the relationship between intracranial artery stenosis and SVD burden. PURPOSE: To investigate whether SVD burden correlates with severity of intracranial LAD. STUDY TYPE: Retrospective. POPULATION: Five hundred and sixteen patients with LAD of arterial circulation were enrolled from one hospital, including 384 males (59 ± 11 years) and 132 females (60 ± 12 years). FIELD STRENGTH/SEQUENCE: 3 T. T1 -weighted fast spin echo (T1 W FSE), T2 W FSE, T2 fluid attenuated inversion recovery, diffusion-weighted imaging, susceptibility-weight imaging, and time-of-flight magnetic resonance angiography. ASSESSMENT: The LAD was divided into mild stenosis (<30%), moderate stenosis (30%-69%), and severe stenosis (≥70%). The Standard for Reporting Vascular Changes on Neuroimaging criteria was used to rate the SVD burden according to the level of white matter hyperintensity (WMH), perivascular space (PVS), cerebral microbleed (CMB), and lacunes. STATISTICAL TESTS: Lilliefors test, ANOVA, chi-squared test, Mann-Whitney U test, Wilcoxon signed rank test, Bonferroni test, Spearman's correlation, logistic regression, and Cohen's kappa test. RESULTS: The grade scores for centrum semiovale PVS (CS-PVS) were positively correlated with the degree of stenosis (R = 0.413), whereas the presence of severe basal ganglia PVS (BG-PVS) was associated with CMB (R = 0.508), lacunes (R = 0.365), and severe WMH (R = 0.478). In multivariate analysis, severe CS-PVS (adjusted odds ratio [aOR], 3.1; 95% confidence interval [CI], 1.9-4.8) and lacunes (aOR, 2.1; 95% CI, 1.3-3.4) were associated with severe stenosis of LAD. In addition, CS-PVS was related to severe stenosis in a dose-dependent manner: when CS-PVS score was 3 and 4, the aORs of severe stenosis were 1.9 and 7.7, respectively. DATA CONCLUSION: The severity of LAD in anterior circulation is associated with SVD burden, which suggests that different SVD burden may be used for risk stratification in LAD. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Structural insights into the cofactor-assisted substrate recognition of yeast methylglyoxal/isovaleraldehyde reductase Gre2.

Saccharomyces cerevisiae Gre2 (EC1.1.1.283) serves as a versatile enzyme that catalyzes the stereoselective reduction of a broad range of substrates including aliphatic and aromatic ketones, diketones, as well as aldehydes, using NADPH as the cofactor. Here we present the crystal structures of Gre2 from S. cerevisiae in an apo-form at 2.00Å and NADPH-complexed form at 2.40Å resolution. Gre2 forms a homodimer, each subunit of which contains an N-terminal Rossmann-fold domain and a variable C-terminal domain, which participates in substrate recognition. The induced fit upon binding to the cofactor NADPH makes the two domains shift toward each other, producing an interdomain cleft that better fits the substrate. Computational simulation combined with site-directed mutagenesis and enzymatic activity analysis enabled us to define a potential substrate-binding pocket that determines the stringent substrate stereoselectivity for catalysis.

Structural snapshots of yeast alkyl hydroperoxide reductase Ahp1 peroxiredoxin reveal a novel two-cysteine mechanism of electron transfer to eliminate reactive oxygen species.

Peroxiredoxins (Prxs) are thiol-specific antioxidant proteins that protect cells against reactive oxygen species and are involved in cellular signaling pathways. Alkyl hydroperoxide reductase Ahp1 belongs to the Prx5 subfamily and is a two-cysteine (2-Cys) Prx that forms an intermolecular disulfide bond. Enzymatic assays and bioinformatics enabled us to re-assign the peroxidatic cysteine (C(P)) to Cys-62 and the resolving cysteine (C(R)) to Cys-31 but not the previously reported Cys-120. Thus Ahp1 represents the first 2-Cys Prx with a peroxidatic cysteine after the resolving cysteine in the primary sequence. We also found the positive cooperativity of the substrate t-butyl hydroperoxide binding to Ahp1 homodimer at a Hill coefficient of ∼2, which enabled Ahp1 to eliminate hydroperoxide at much higher efficiency. To gain the structural insights into the catalytic cycle of Ahp1, we determined the crystal structures of Ahp1 in the oxidized, reduced, and Trx2-complexed forms at 2.40, 2.91, and 2.10 Šresolution, respectively. Structural superposition of the oxidized to the reduced form revealed significant conformational changes at the segments containing C(P) and C(R). An intermolecular C(P)-C(R) disulfide bond crossing the A-type dimer interface distinguishes Ahp1 from other typical 2-Cys Prxs. The structure of the Ahp1-Trx2 complex showed for the first time how the electron transfers from thioredoxin to a peroxidase with a thioredoxin-like fold. In addition, site-directed mutagenesis in combination with enzymatic assays suggested that the peroxidase activity of Ahp1 would be altered upon the urmylation (covalently conjugated to ubiquitin-related modifier Urm1) of Lys-32.

Nuclear Factor Erythroid 2-Related Factor 2 is Essential for Low-Normobaric Oxygen Treatment-Mediated Blood-Brain Barrier Protection Following Ischemic Stroke.

Cerebral ischemia/reperfusion (I/R) injury increases blood-brain barrier (BBB) permeability, leading to hemorrhagic transformation and brain edema. Normobaric oxygen (NBO) is a routine clinical treatment strategy for this condition. However, its neuroprotective effects remain controversial. This study investigated the effect of different NBO concentrations on I/R injury and explores the involvement of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the underlying mechanism. A mouse middle cerebral artery occlusion (MCAO) model, and an oxygen and glucose deprivation (OGD) model featuring mouse brain microvascular endothelial cells (ECs) called bEnd.3, were used to investigate the effect of NBO on I/R injury. A reactive oxygen species (ROS) inducer and Nrf2-knockdown by RNA were used to explore whether the Nrf2 pathway mediates the effect of NBO on cerebrovascular ECs. In the early stage of MCAO, 40% O2 NBO exposure significantly improved blood perfusion in the ischemic area and effectively relieved BBB permeability, cerebral edema, cerebral injury, and neurological function after MCAO. In the OGD model, 40% O2 NBO exposure significantly reduced apoptosis, inhibited ROS generation, reduced ER stress, upregulated the expression of tight junction proteins, and stabilized the permeability of ECs. Blocking the Nrf2 pathway nullified the protective effect of 40% O2 NBO on ECs after OGD. Finally, our study confirmed that low concentrations of NBO have a neuroprotective effect on I/R by activating the Nrf2 pathway in ECs.

Structural plasticity of the thioredoxin recognition site of yeast methionine S-sulfoxide reductase Mxr1.

The methionine S-sulfoxide reductase MsrA catalyzes the reduction of methionine sulfoxide, a ubiquitous reaction depending on the thioredoxin system. To investigate interactions between MsrA and thioredoxin (Trx), we determined the crystal structures of yeast MsrA/Mxr1 in their reduced, oxidized, and Trx2-complexed forms, at 2.03, 1.90, and 2.70 Å, respectively. Comparative structure analysis revealed significant conformational changes of the three loops, which form a plastic "cushion" to harbor the electron donor Trx2. The flexible C-terminal loop enabled Mxr1 to access the methionine sulfoxide on various protein substrates. Moreover, the plasticity of the Trx binding site on Mxr1 provides structural insights into the recognition of diverse substrates by a universal catalytic motif of Trx.

A friend to the airways: a review of the emerging clinical importance of the bronchial arterial circulation.

Lungs receive the bulk of their blood supply through the pulmonary arteries. The bronchial arteries, on the other hand, vascularize the bronchi and their surroundings. These two arteries anastomose near the alveolar ducts. Contrary to the pulmonary circulation which is fairly well studied, the bronchial arteries have been appreciated more by their absence, and in some cases, by an interruption in the pulmonary arterial flow. Therefore, a more accurate anatomical and functional knowledge of these atherosclerosis-resistant vessels is needed to help surgeons and clinicians to avoid iatrogenic injuries during pulmonary interventions. In this review, we have revisited the anatomy and pathophysiology of the bronchial arteries in humans, considering the recent advances in imaging techniques. We have also elaborated on the known clinical applications of these arteries in both the pathogenesis and management of common pulmonary conditions.

Complete mitochondrial genome of Dermanyssus gallinae (Arthropoda: Dermanyssidae) isolate from China.

The complete mitochondrial genome of Dermanyssus gallinae isolated from China is reported for the first time in this study. Its entire mitogenome is 16, 184 bp in length, contained 13 protein-coding genes, 2 ribosomal RNA genes, 21 transfer RNA genes, and 1 non-coding region. The phylogenetic analysis by maximum likelihood method show that D. gallinae isolated from China is in the same clade with the genus of Psoroptes. This is the first complete mitochondrial genome of D. gallinae.

First description of the mitogenome and phylogeny:Aedes vexansand Ochlerotatus caspius of the Tribe Aedini (Diptera: Culicidae).

Culicidae, the mosquito family, includes more than 3600 species subdivided into the subfamilies Anophelinae and Culicinae. One-third of mosquitoes belong to the Aedini tribe, which is subordinate to the subfamily Culicinae, which comprises common vectors of viral zoonoses. The tribe of Aedini is extremely diverse in morphology and geographical distribution and has high ecological and medical significance. However, knowledge about the systematics of the Aedini tribe is still limited owing to its large population and the similar morphological characteristics of its species. This study provides the first description of the complete mitochondrial (mt) genome sequence of Aedes vexans and Ochlerotatus caspius belonging to the Aedini tribe. The mt genomes of A. vexans and O. caspius are circular molecules that are 15,861 bp and 15,954 bp in size, with AT contents of 78.54% and 79.36%, respectively. Both the circular mt genomes comprise 37 functional subunits, including 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes (tRNAs), and a control region (also known as the AT-rich region). The most common start codons are ATT/ATG, apart from cox1 (TCG) and nad5 (GTG), while TAA is the termination codon for all PCGs. All tRNAs have a typical clover leaf structure, except tRNA Ser1. Phylogenetic analysis of the concatenated, aligned amino acid sequences of the 13 PCGs showed that A. vexans gathered with Aedes sp. in a sister taxon, and O. caspius gathered with Ochlerotatus sp. in a sister taxon. The findings from the present study support the concept of monophyly of all groups, ratify the current taxonomic classification, and provide vital molecular marker resources for further studies of the taxonomy, population genetics, and systematics of the Aedini tribe.

Structural insights into the cofactor-assisted substrate recognition of yeast quinone oxidoreductase Zta1.

Quinone oxidoreductase (QOR EC1.6.5.5) catalyzes the reduction of quinone to hydroxyquinone using NADPH as a cofactor. Here we present the crystal structure of the ζ-crystallin-like QOR Zta1 from Saccharomycescerevisiae in apo-form at 2.00 Šand complexed with NADPH at 1.59 Šresolution. Zta1 forms a homodimer, with each subunit containing a catalytic and a cofactor-binding domain. Upon NADPH binding to the interdomain cleft, the two domains shift towards each other, producing a better fit for NADPH, and tightening substrate binding. Computational simulation combined with site-directed mutagenesis and enzymatic activity analysis defined a potential quinone-binding site that determines the stringent substrate specificity. Moreover, multiple-sequence alignment and kinetics assays implied that a single-residue change from Arg in lower organisms to Gly in vertebrates possibly resulted in elevation of enzymatic activity of ζ-crystallin-like QORs throughout evolution.

Crystal structure of the 30 K protein from the silkworm Bombyx mori reveals a new member of the ß-trefoil superfamily.

The hemolymph of the fifth instar larvae of the silkworm Bombyx mori contains a group of homologous proteins with a molecular weight of approximately 30 kDa, termed B. mori low molecular weight lipoproteins (Bmlps), which account for about 5% of the total plasma proteins. These so-called "30 K proteins" have been reported to be involved in the innate immune response and transportation of lipid and/or sugar. To elucidate their molecular functions, we determined the crystal structure of a 30 K protein, Bmlp7, at 1.91Å. It has two distinct domains: an all-α N-terminal domain (NTD) and an all-ß C-terminal domain (CTD) of the ß-trefoil fold. Comparative structural analysis indicates that Bmlp7 represents a new family, adding to the 14 families currently identified, of the ß-trefoil superfamily. Structural comparison and simulation suggest that the NTD has a putative lipid-binding cavity, whereas the CTD has a potential sugar-binding site. However, we were unable to detect the binding of either lipid or sugar. Therefore, further investigations are needed to characterize the molecular function of this protein.

Crystal structures and putative interface of Saccharomyces cerevisiae mitochondrial matrix proteins Mmf1 and Mam33.

The yeast Saccharomyces cerevisiae mitochondrial matrix factor Mmf1, a member in the YER057c/Yigf/Uk114 family, participates in isoleucine biosynthesis and mitochondria maintenance. Mmf1 physically interacts with another mitochondrial matrix protein Mam33, which is involved in the sorting of cytochrome b2 to the intermembrane space as well as mitochondrial ribosomal protein synthesis. To elucidate the structural basis for their interaction, we determined the crystal structures of Mmf1 and Mam33 at 1.74 and 2.10 Å, respectively. Both Mmf1 and Mam33 adopt a trimeric structure: each subunit of Mmf1 displays a chorismate mutase fold with a six-stranded ß-sheet flanked by two α-helices on one side, whereas a subunit of Mam33 consists of a twisted six-stranded ß-sheet surrounded by five α-helices. Biochemical assays combined with structure-based computational simulation enable us to model a putative complex of Mmf1-Mam33, which consists of one Mam33 trimer and two tandem Mmf1 trimers in a head-to-tail manner. The two interfaces between the ring-like trimers are mainly composed of electrostatic interactions mediated by complementary negatively and positively charged patches. These results provided the structural insights into the putative function of Mmf1 during mitochondrial protein synthesis via Mam33, a protein binding to mitochondrial ribosomal proteins.

Structural basis for the different activities of yeast Grx1 and Grx2.

Yeast glutaredoxins Grx1 and Grx2 catalyze the reduction of both inter- and intra-molecular disulfide bonds using glutathione (GSH) as the electron donor. Although sharing the same dithiolic CPYC active site and a sequence identity of 64%, they have been proved to play different roles during oxidative stress and to possess different glutathione-disulfide reductase activities. To address the structural basis of these differences, we solved the crystal structures of Grx2 in oxidized and reduced forms, at 2.10 A and 1.50 A, respectively. With the Grx1 structures we previously reported, comparative structural analyses revealed that Grx1 and Grx2 share a similar GSH binding site, except for a single residue substitution from Asp89 in Grx1 to Ser123 in Grx2. Site-directed mutagenesis in combination with activity assays further proved this single residue variation is critical for the different activities of yeast Grx1 and Grx2.

MISSA is a highly efficient in vivo DNA assembly method for plant multiple-gene transformation.

We describe a highly efficient in vivo DNA assembly method, multiple-round in vivo site-specific assembly (MISSA), which facilitates plant multiple-gene transformation. MISSA is based on conjugational transfer, which is driven by donor strains, and two in vivo site-specific recombination events, which are mediated by inducible Cre recombinase and phage lambda site-specific recombination proteins in recipient strains, to enable in vivo transfer and in vivo assembly of multiple transgenic DNA. The assembly reactions can be performed circularly and iteratively through alternate use of the two specially designed donor vectors. As proof-of-principle experiments, we constructed a few plant multigene binary vectors. One of these vectors was generated by 15 rounds of MISSA reactions and was confirmed in transgenic Arabidopsis (Arabidopsis thaliana). As MISSA simplifies the tedious and time-consuming in vitro manipulations to a simple mixing of bacterial strains, it will greatly save time, effort, and expense associated with the assembly of multiple transgenic or synthetic DNA. The principle that underlies MISSA is applicable to engineering polygenic traits, biosynthetic pathways, or protein complexes in all organisms, such as Escherichia coli, yeast, plants, and animals. MISSA also has potential applications in synthetic biology, whether for basic theory or for applied biotechnology, aiming at the assembly of genetic pathways for the production of biofuels, pharmaceuticals, and industrial compounds from natural or synthetic DNA.

Structures of yeast glutathione-S-transferase Gtt2 reveal a new catalytic type of GST family.

Glutathione-S-transferases (GSTs) are ubiquitous detoxification enzymes that catalyse the conjugation of electrophilic substrates to glutathione. Here, we present the crystal structures of Gtt2, a GST of Saccharomyces cerevisiae, in apo and two ligand-bound forms, at 2.23 A, 2.20 A and 2.10 A, respectively. Although Gtt2 has the overall structure of a GST, the absence of the classic catalytic essential residues--tyrosine, serine and cysteine--distinguishes it from all other cytosolic GSTs of known structure. Site-directed mutagenesis in combination with activity assays showed that instead of the classic catalytic residues, a water molecule stabilized by Ser129 and His123 acts as the deprotonator of the glutathione sulphur atom. Furthermore, only glycine and alanine are allowed at the amino-terminus of helix-alpha1 because of stereo-hindrance. Taken together, these results show that yeast Gtt2 is a novel atypical type of cytosolic GST.

The Role of Ranged Horses in Eco-Epidemiology of Rickettsia raoultii Infection in China.

Rickettsia raoultii is a tick-borne pathogen that infects humans; however, the vertebrate hosts of this pathogen have not been clearly defined. Our molecular examination of Rickettsia spp. infecting mammals and ticks in China, identified the gltA, ompA, and 17KD gene sequences of R. raoultii in horses and their ticks. This indicates a role of horses in R. raoultii epidemiology.

Identification of Myoferlin, a Potential Serodiagnostic Antigen of Clonorchiasis, via Immunoproteomic Analysis of Sera From Different Infection Periods and Excretory-Secretory Products of Clonorchis sinensis.

Clonorchiasis, which is caused by Clonorchis sinensis, is an important foodborne disease worldwide. The excretory-secretory products (ESPs) of C. sinensis play important roles in host-parasite interactions by acting as causative agents. In the present study, the ESPs and sera positive for C. sinensis were collected to identify proteins specific to the sera of C. sinensis (i.e., proteins that do not cross-react with Fasciola hepatica and Schistosoma japonicum) at different infection periods. Briefly, white Japanese rabbits were artificially infected with C. sinensis, and their sera were collected at 7 days post-infection (dpi), 14 dpi, 35 dpi, and 77 dpi. To identify the specific proteins in C. sinensis, a co-immunoprecipitation (Co-IP) assay was conducted using shotgun liquid chromatography tandem-mass spectrometry (LC-MS/MS) to pull down the sera roots of C. sinensis, F. hepatica, and S. japonicum. For the annotated proteins, 32, 18, 39, and 35 proteins specific to C. sinensis were pulled down by the infected sera at 7, 14, 35, and 77 dpi, respectively. Three proteins, Dynein light chain-1, Dynein light chain-2 and Myoferlin were detected in all infection periods. Of these proteins, myoferlin is known to be overexpressed in several human cancers and could be a promising biomarker and therapeutic target for cancer cases. Accordingly, this protein was selected for further studies. To achieve a better expression, myoferlin was truncated into two parts, Myof1 and Myof2 (1,500 bp and 810 bp), based on the antigenic epitopes provided by bioinformatics. The estimated molecular weight of the recombinant proteins was 57.3 ku (Myof1) and 31.3 ku (Myof2). Further, both Myof1 and Myof2 could be probed by the sera from rabbits infected with C. sinensis. No cross-reaction occurred with the positive sera of S. japonica, F. hepatica, and negative controls. Such findings indicate that myoferlin may be an important diagnostic antigen present in the ESPs. Overall, the present study provides new insights into proteomic changes between ESPs and hosts in different infection periods by LC-MS/MS. Moreover, myoferlin, as a biomarker, may be used to develop an objective method for future diagnosis of clonorchiasis.

Characterization of the complete mitochondrial genomes of Coronocyclus labiatus and Cylicodontophorus bicoronatus: Comparison with Strongylidae species and phylogenetic implication.

Coronocyclus labiatus and Cylicodontophorus bicoronatus are two significant horse parasitic nematodes which are classified into subfamily Cyathostominae, family Strongylidae, however, the classification of these nematodes has been controversial for more than a century. Mitochondrial (mt) genomes are considered valuable sources for parasite taxonomy, population genetics, and systematics studies. In the present study, the mt genomes of Co. labiatus and Cd. bicoronatus (type species) were determined and subsequently compared with those from closely related species by phylogenetic analysis based on concatenated datasets of amino acid sequences predicted from mt protein-coding genes. The complete mt genomes of Co. labiatus and Cd. bicoronatus were circular with 13,827 bp and 13,753 bp in size, respectively. Both mt genomes consisted of a total of 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two non-coding regions. All protein coding genes were transcribed in the same direction, and the gene order in both mt genomes belonged to the gene arrangement type 3 (GA3). There were 19 intergenic spacers with 1 bp to 35 bp and one overlap with 4 bp in mt genome of Co. labiatus, and 22 intergenic spacers with 1-29 bp in size but no overlap in the mt genome of Cd. bicoronatus. The A + T content of Co. labiatus and Cd. bicoronatus mt genomes were 75.87 % and 75.16 %, respectively. Similar to mt genones of other Strongylidae species published in GenBank, they also exhibited a strong A + T bias not only in the nucleotide composition but also in codon usage. Comparative analyses of mt genomes nucleotide sequence showed that mt genomes of Co. labiatus and Cd. bicoronatus had higher identities to that of Cylicostephanus goldi (90.3 % and 86.9 %, respectively), followed by those of two Cyathostomum species (89.9∼90.0 %; 86.4 %), respectively. Phylogenetic analyses using mt genomes of 26 Strongyloidea nematodes revealed that Co. labiatus was closely related to Cyathostomum species, and Cd. bicoronatus formed a distinct branch with Cyathostominae species, which was closer to Triodontophorus than Poteriostomum imparidentatum. We concluded Coronocyclus might be closely related with Cyathostomum but represent a distinct genus based on comparative mt genome sequences and phylogenetic analyses. The availability of complete mt genome sequences of Co. labiatus and Cd. bicoronatus provides new and useful genetic markers for further studies on Strongylidae nematodes.

Structure of Hsp33/YOR391Cp from the yeast Saccharomyces cerevisiae.

Saccharomyces cerevisiae Hsp33/YOR391Cp is a member of the ThiI/DJ-1/PfpI superfamily. Hsp33 was overexpressed in Escherichia coli and its crystal structure was determined at 2.40 Šresolution. Structural comparison revealed that Hsp33 adopts an α/ß-hydrolase fold and possesses the putative Cys-His-Glu catalytic triad common to the Hsp31 family, suggesting that Hsp33 and Hsp31 share similar aminopeptidase activity, while structural deviations in helices α2-α3 of the core domain might be responsible for the access of different peptide substrates.

Comparative analyses of complete ribosomal DNA sequences of Clonorchis sinensis and Metorchis orientalis: IGS sequences may provide a novel genetic marker for intraspecific variation.

Both Clonorchis sinensis and Metorchis orientalis are the fish-borne zoonotic trematodes, and have a wide distribution of southeastern Asia, especially in China. Due to the similar morphology, life cycle, and parasitic positions are difficult to differentiate between both metacercariae. In the present study, the complete rDNA sequences of five C. sinensis and five M. orientalis were obtained and compared for the first time. And the IGS rDNA sequences were tested as a genetic marker. The results showed complete rDNA lengths of C. sinensis were range from 8049 bp to 8391 bp, including 1991 bp, 1116 bp, 3854 bp, and 1088-1430 bp belonging to 18S, ITS, 28S and IGS, respectively. And the complete rDNA lengths of M. orientalis were range from 7881 bp to 9355 bp, including 1991 bp, 1077 bp, 3856 bp, and 957-2431 bp belonging to 18S, ITS, 28S and IGS, respectively. Comparative analyses reveal length difference main in IGS, which has higher intraspecific and interspecific variations than other ribosomal regions. Forty four repeat (forward and inverted) sequences were found in the complete rDNAs of C. sinensis and M. orientalis. The phylogenetic analyses showed that the sequences of ITS1, ITS2, 18S and 28S could be used as different level genetic markers. In IGS phylogenetic tree, Opisthorchiidae, Paramphistomidae, Dicrocoeliidae, and Schistosomatidae formed monophyletic groups, and the same length sequences were clustered together in the same species. These findings of the present study provide the new molecular data for studying the complete rDNA of C. sinensis and M. orientalis, and indicate IGS sequences may used as a novel genetic marker for studying intraspecific variation in trematodes.