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The clam Coelomactra antiquata (Spengler, 1802) is one of the most economically important marine bivalves in China. Previous genetic analysis shows that C. antiquata possibly consists of two cryptic species, a northern and a southern lineage. Some differences between the two lineages are observed in their morphology and fitness in aquaculture. However, little is known about the genetic basis of these differences. In this study, a comparative transcriptomics study was performed to provide additional information for delineating the cryptic species of C. antiquata, as well as insights into the adaptive evolution in the southern lineage of C. antiquata. A total of 4377 orthologous genes were identified using a phylogenetic tree-based approach. The Kimura 2-parameter genetic distances were 0.0385 between the two lineages of C. antiquata, and 0.006 within the northern lineage. The sequence divergences supports that the lineages represent two cryptic species. We identified 28 positively selected genes (PSGs) from the southern lineage of C. antiquata using a modified branch-site model. The PSGs were implicated in innate immune responses, metabolism, development, cell division, transmembrane transport, and signaling processes, which could be related to the higher disease resistance, growth rate, and adaptability of the southern lineage than its northern counterpart. The comparative transcriptome analysis provides a foundation for future investigations on the biological differences between the two lineages of C. antiquata.

Nanostructured carbon materials have been extensively used for encapsulating sulfur and improving cyclic stability of lithium-sulfur (Li-S) batteries, but high carbon content and low packing density greatly limit their volumetric energy density. Herein, we present MXene-based Ti3C2T x (T x stands for the surface terminations) nanodots-interspersed Ti3C2T x nanosheet (TCD-TCS) to accomplish spatial immobilization and conversion of high-loaded sulfur species. Rich surface polar sites in TCD-TCS enhance structural integrity of the resultant electrode, while the absence of the carbon-based materials and conductive additives results in high tap density of the cathode materials. The TCD-TCS/S electrode exhibits an almost theoretical discharge capacity at a medium sulfur loading of 1.8 mg cm-2. Notably, ultrahigh volumetric capacity (1957 mAh cm-3) and high areal capacity (13.7 mAh cm-2) are synchronously achieved at a high sulfur loading of 13.8 mg cm-2. The mechanism study of sulfur evolution during discharge process highlights the importance of the integration of MXene-based nanodots and nanosheets in Li-S batteries. This proposed methodology holds great promise for the development of various high-performance energy storage materials.

The high-speed metal jet generated by the high explosive antitank method to damage the armor vehicles and tanks. The penetration capacity of the high-speed metal jet is proportional to the effective length of the metal jet. In order to improve the effective length of the metal jet, an electromagnetic enhancing system is put forward, and its principle is introduced. The time sequence of the high-speed metal jet and the pulsed magnetic field is analyzed, and the determination method of the time sequence is obtained. Furthermore, the simulation model of the electromagnetic enhancing system is established based on finite element method, and the distribution characteristics of the discharge current, magnetic field, and the electromagnetic force are obtained. Finally, an experiment system of the electromagnetic enhancing system is built and some verification experiments are carried out. With the analysis and the experiments, the conclusions as follows can be drawn: the high-speed metal jet will be reshaped with the effect of the axial pulsed magnetic field, and the effective length will be improved. Furthermore, the optimal time sequence is that when the central sections of the metal jet and magnetic field coil coincide, the discharge current of the magnetic field coil just reaches its peak point.

Lithium–sulfur (Li–S) batteries are one of the promising next-generation energy storage systems. Tremendous efforts have been devoted to developing conductive nanoarchitectures for improving sulfur utilization and cycling stability. MXenes, a family of 2D transition metal carbides, nitrides and carbonitrides, have recently captured considerable attention in energy storage and conversion. Herein, we have summarized recent advances of MXene-based materials in the cathodes, anodes and separators of Li–S batteries and highlighted the theoretical and experimental importance of high polarity and rich surface chemistry in polysulfide trapping. Their superiority for suppressing polysulfide shuttling and improving sulfur utilization has been demonstrated. We have also concluded the perspectives and challenges that need to be addressed for MXene-based Li–S batteries and some new strategies have been proposed to improve the electrochemical performance, which shed light on future development of MXene-based materials in high-energy-density Li–S batteries.

High gravimetric, areal and volumetric capacities together with long lifetime are key indexes for the applications of lithium-sulfur (Li-S) batteries in compact space. The sulfur host materials play pivotal roles in the practical deployment. Herein, one type of new heterostructure nanosheets composed of cobalt boride (CoB) on nitrogen, boron-codoped porous carbon (NBC), which is constructed through molten salt-assisted strategy using ZIF-67-encapsulated ZIF-8 as precursors is reported on. Benefiting from strong interfacial electronic interactions between binary sulfiphilic CoB and porous NBC, the CoB/NBC-S electrode exhibits the excellent cycling stability with low average capacity decay of 0.013% in ultralong 1500 cycles at high rate of 5 C. Remarkably, the electrode with high sulfur content of 82 wt% and high sulfur loading of 5.8 mg cm-2 delivers gravimetric capacity of 1309 mA h g-1 , areal capacity of 7.59 mA h cm-2 , and volumetric capacity of 1355 mA h cm-3 at 0.1 C. The favorable electrochemical performance can rival with the state-of-the-art of those in the reported nanosheets-based sulfur cathodes. This study provides new methodology for the design of heterostructure nanosheets of metal borides to achieve energy density and longevity of Li-S batteries.

Transition metal nitrides are promising mediators for improving the electrochemical performance of lithium–sulfur (Li–S) batteries, but the synthesis of ultrafine and durable nanoparticles in the absence of ammonia gas is still a great challenge. Herein, we reported a new method for the fabrication of ultrafine vanadium nitride (VN) nanoparticles uniformly embedded into N-doped porous carbon using a main-chain imidazolium-based ionic polymer (ImIP) containing metavanadate anions as a precursor. ImIP not only serves as sole carbon and nitrogen sources, but also effectively inhibits the aggregation and coalescence of VN nanoparticles during pyrolysis. Benefiting from the ultrafine particle size, high polarity and good electrocatalytic effects of VN, both redox kinetics of sulfur species and chemical adsorbability toward polysulfides are greatly expedited. The resultant electrode exhibits superior cycling stability with a low average capacity decay rate of 0.035% for 1200 cycles at a high rate of 5 C. This work develops a facile ammonia-free approach to fabricate ultrafine VN nanoparticles for improving electrochemical behaviors of Li–S batteries.

To assess the genetic background of the germplasm resource of rainbow clam Moerella iridescens along China coasts, population genetic structure and genetic diversity of rainbow clam from five geographical populations in the Yellow Sea and the East China Sea (Lianyungang, Chongming, Cixi, Zhoushan, and Ningde) were analyzed based on rDNA (ITS1-5.8S-ITS2) sequences. Forty-Seven rDNA haplotypes were identified among 109 rainbow clam individuals of the five populations. Gen4 and Gen21 were the dominant haplotypes, accounting for 49.5% of rDNA whole gene sequences, and shared by the five populations. Six to eight exclusive haplotypes were found in each population. The average haplotype diversity index (HD) of the five populations was 0.8733. The genetic distance among populations ranged from 0.002 to 0.004, and haplotypes from the same population were not clustered in a single clade. Molecular variance analysis (AMOVA) demonstrated that the main genetic differentiation mainly occurred within population, and the genetic differentiation coefficient (FST) among five populations was between -0.02836 and 0.01896, which meant that no genetic differentiation among populations occurred. Overall, the five geographical populations showed a high genetic diversity, but no evident genetic structure or genetic differentiation.

Background To avoid destructive sampling for conservation and genetic assessment, we isolated the DNA of clam Cyclina sinensis from their feces. DNA electrophoresis and PCR amplification were used to determine the quality of fecal DNA. And we analyzed the effects of different conditions on the degradation of feces and fecal DNA. Results The clear fecal DNA bands were detected by electrophoresis, and PCR amplification using clam fecal DNA as template was effective and reliable, suggesting that clam feces can be used as an ideal material for noninvasive DNA isolation. In addition, by analyzing the effects of different environmental temperatures and soaking times on the degradation of feces and fecal DNA, we found that the optimum temperature was 4 °C. In 15 days, the feces maintained good texture, and the quality of fecal DNA was good. At 28 °C, the feces degraded in 5 days, and the quality of fecal DNA was poor. Conclusions The clam feces can be used as an ideal material for noninvasive DNA isolation. Moreover, the quality of fecal DNA is negatively correlated with environmental temperature and soaking time.

Nanostructured carbon materials have been extensively used for encapsulating sulfur and improving cyclic stability of lithium-sulfur (Li-S) batteries, but high carbon content and low packing density greatly limit their volumetric energy density. Herein, we present MXene-based Ti

Additional file 2: Figure S2. Agarose gel electrophoresis of PCR amplification products Lane M, DNA marker; lane N, negative control; lane F, PCR amplification products of foot DNA; lanes 1–20, PCR amplification products of fecal DNA (N = 20).

It is of great significance to mediate the redox kinetics and shuttle effect of polysulfides in pursuit of high-energy-density and long-life lithium-sulfur (Li-S) batteries. Herein, a new strategy is proposed based on the electrostatic attraction and catalytic effect of polysulfides for the modification of the polypropylene (PP) separator. Guanidinium-based ionic-covalent organic nanosheets (iCON) on the surface of Ti3 C2 is presented as a coating layer for the PP separator. The synergetic effects of Ti3 C2 and iCON provide new platforms to suppress the shuttle effect of polysulfides, expedite the redox kinetics of sulfur species, and promote efficient conversion of the intercepted polysulfides. The functional separator endows carbon nanotube/sulfur cathodes with excellent electrochemical performance. The average capacity decay per cycle within 2000 cycles at 2 C is as low as 0.006%. The separator is even effective in the case of sulfur content of 90 wt% and sulfur loading of 7.6 mg cm-2 ; the reversible capacity, areal capacity, and volumetric capacity at 0.1 C are as high as 1186 mA h g-1 , 9.01 mA h cm-2 , and 1201 mA h cm-3 , respectively. This work provides a promising approach toward separator modification for the development of high-performance Li-S batteries.

Conductive porous carbons are promising sulfur host materials for improving mass and areal capacities in lithium-sulfur (Li–S) batteries, but they face a few congenital deficiencies, such as low tap density and weak entrapment ability toward lithium polysulfides (LiPS), resulting in poor volumetric performance. Herein, we report a self-supporting cathode based on electrochemical active graphene-like RuO2 (GRO) without the incorporation of any carbon hosts and additives to synchronously acquire high mass, areal and volumetric capacities. It has been certified that dynamic evolutions of both conductive GRO host and sulfur guest during cell operation expedite chemisorption/conversion of LiPS and regulate nucleation/growth of solid Li2S, which enables GRO-S with medium sulfur loading to achieve an almost theoretical capacity at 0.2 C. Remarkably, the electrode with higher sulfur loading of 8.4 mg cm−2 delivers mass, areal and volumetric capacities of 1225 mAh g−1, 10.3 mAh cm−2 and 1981 mAh cm−3 at 0.2 C, respectively. The volumetric capacity records the highest value in reported Li–S batteries. The cathode material reported in this work opens new avenues for the development of high-energy-density and long-life Li–S batteries.

In statistics mean absolute deviation plays an important role in measuring spread of a data. In this paper, we focus on using the jackknife, the adjusted and the extended jackknife empirical likelihood methods to construct confidence intervals for the mean absolute deviation of a random variable. The empirical log-likelihood ratio statistic is derived whose asymptotic distribution is a standard chi-square distribution. The results of simulation study show the comparison of the average length and coverage probability by using jackknife empirical likelihood methods and normal approximation method. The proposed adjusted and extended jackknife empirical likelihood methods perform better than other methods, in particular for skewed distributions. We use real data sets to illustrate the proposed jackknife empirical likelihood methods.

To improve the defense capability of passive electromagnetic armor against shaped-charge jet (SCJ), according to the superposition principle and the linear perturbation theory, the SCJ disturbance control equations are constructed and the 3-D equation is reduced to 1-D equation, consequently, the instability growth rates of the pinch and kink of SCJ and the varying law of instability growth rates with time and yield stress are obtained under the axial pulse current, which indicate that the instabilities must occur as long as the perturbations exit. Meanwhile, the SCJ deformation can be calculated through numerical method. The pinching experiments with a 39.2-mm diameter armor-piercing projectile proceeded when the charging voltage is 5370 V and the peak current is 140 kA. The kinking experiments with a 1.75-mm diameter copper wire proceeded when the charging voltage is 5140 V and the peak current is 43 kA. The experimental results demonstrate that axial pulse current can destroy the SCJ because of necking or kinking perturbation and confirm the validity of the theoretical analysis.

Coelomactra antiquata is a famous delicacy and a promising new candidate for aquaculture, which belongs to the family Mactridae (Mollusca: Veneroida). The complete mitochondrial genome of C. antiquata (Liao Ning province, in China, LN) was finished, which is the first representative from this province. The results showed that the total length of LN-mtDNA sequence is 16,797 bp and the content of A + T is 65.01%. It encodes 35 genes, including 12 protein-coding genes, 21 transfer RNA genes and two ribosomal RNA genes. All coding genes are encoded on the heavy strand. Compared with the typical gene content of animal mitochondrial genomes, atp8 and trnSer(UCN) genes are missing in the mitochondrial genome. The complete mitochondrial genome contains 26 non-coding regions (1598 bp), one major non-coding region consists of 1046 bp in which 4.9 tandem repeat sequences (99bp per sequence) was observed. The phylogenetic tree showed that Liaoning population was clustered into one clade with Shandong (Rizhao, Jiaonan and Jimo) and Guangxi (Beihai) populations, meanwhile all of them are far from the Fujian populations (Pingtan, Zhangzhou and Changle). So, Liaoning, Shandong and Guangxi populations have a close relationship. Actually, Fujian is located between Liaoning, Shandong and Guangxi. So, the result challenges the previously assumed relevance between geographic distance and genetic distance. The genetic distance of Liaoning C. antiquata and Fujian (Changle, Zhangzhou and Pingtan) C. antiquata (0.176–0.177) is greater than the genetic distance between Mytilus galloprovincialis and Mytilus trossulus (0.160). The genetic difference of Liaoning population and Fujian populations has reached species level.

The tracking ability and robustness of the Unscented Particle filter based on the minimum variance estimation principle are weakened when the actual data is abruptly changed. A fading factor unscented particle filter (FFUPF) algorithm is proposed in this paper, which can improve the accuracy of the unscented particle filtering and increase the tracking ability and robustness. The proposed fading factor is used to adaptively adapt the time-varying system noise. And the proposed algorithm infuses the latest observation data in the prior distribution update phase, designs the importance density function by fading factor, and makes it more close to the system status posterior probability density. Simulation has been performed by using an illustrative example and results have been provided to demonstrate the validity of the proposed algorithm as well as its improved performance over the conventional one.

The tanks and armor vehicles can be damaged by high-speed metal jet caused by the High Explosive Anti-Tank (HEAT). In order to improve the effective length and the penetration capacity of the metal jet, the electromagnetic enhancing system for the metal jet is put forward. Aiming to the effect of the time sequence to the performance of the metal jet, the relationship between the times of the high-speed metal jet and the strong pulsed magnetic field is analyzed, and then a numerical simulation model is established based on the Transient Magnetic Solver. After that the validity of the electromagnetic enhancing system for high-speed metal jet is verified, and the distribution characteristics of the magnetic field and the current density are obtained. It can draw the conclusion that the high-speed metal jet can become deformed with the effect of the axial pulsed magnetic field. And then the high-speed metal jet cannot be put off by the stretching force caused by the uneven velocity distribution. Furthermore, the radius of metal jet may become more even and the effective length will be extended. Meanwhile, the best delay time is to make the peak point of the discharge current just coincide with the time when the center sections of the metal jet and the magnetic field coil are consistent.

Hollow nanostructures with intricate interior and catalytic effects hold great promise for the construction of advanced lithium-sulfur batteries. Herein, a double-shelled hollow polyhedron with inlaid cobalt nanoparticles encapsulated by nitrogen-doped carbon (Co/NC) nanodots (Co-NC@Co9 S8 /NPC) is reported, which is acquired by using imidazolium-based ionic-polymer-encapsulated zeolitic imidazolate framework-67 as a core-shelled precursor. The Co/NC nanodots promote redox kinetics and chemical adsorbability toward polysulfides, while the interconnected double shells serve as a nanoscale electrochemical reaction chamber, which effectively suppresses the polysulfide shuttling and accelerates ion/electron transport. Benefiting from structural engineering and reaction kinetics modulation, the Co-NC@Co9 S8 /NPC-S electrode exhibits high cycling stability with a low capacity decay of 0.011% per cycle within 2000 cycles at 2 C. The electrode still shows high rate performance and cyclability over 500 cycles even in the case of high sulfur loading of 4.5 mg cm-2 and 75 wt% sulfur content. This work provides one type of new hollow nanoarchitecture for the development of advanced Li-S batteries and other energy storage systems.

A full-length cDNA coding lipoprotein lipase (LPL)was cloned from the liver of adult grass carp(Ctenopharyngodon idella) using reverse transcriptionpolymerasechainreaction(RT-PCR)andrapidampli-¢cationofcDNAendsapproaches.ThecDNAobtainedwas 2414bp long with a1524bp open reading frameencoding507aminoacids,includingaputativesignalpeptide 21 amino acids long. The LPL protein has acalculated molecular weight of 57.77kDaandan iso-lectric point of 8.132.The maindomains of LPL, suchas catalytic site, disulphide bridge, N-linked glycosy-lationsite,heparin-bindingdomain,lipid-bindingsiteand site of dimer formation, are basically conservedbetweenthegrasscarpandothervertebrates.Thetis-sue distribution of LPL mRNA in the liver, head kid-ney, mesenteric adipose tissue, heart and whitemuscle of adult grass carp was analysed using thesemi-quantitative RT-PCR methodusing b-actingeneas an internal control; the result showed that the ex-pressionsofLPLmRNAweredetectedinallexaminedtissues of adult grass carp. The expression levels ofLPLinthemesentericadiposetissuewerethehighestamong these tissues, followed by the liver and headkidney and the lowest expression was found in theheartandwhitemuscle.Keywords: Ctenopharyngodon idella, full-lengthcDNA,lipoproteinlipasegene, RACEIntroductionLipoprotein lipase (LPL, EC 3.1.1.34) is a member ofthelipasegenesuperfamily, whichinitiallyconsistedof three mammalian lipases [pancreatic lipase (PL);lipoprotein lipase; and hepatic lipase (HL)] based onamino acid sequence similarity and gene organiza-tion (Saera-Vila, Calduch-Giner, Gomez-Requeni,Medale, Kaushik & Perez-Sanchez 2005). Family sizeincreased when several proteins were subsequentlyadded based on amino acid homology, includingPL-relatedproteins1and2,phosphatidylserinephos-pholiaseA1and endothelial lipase (EL). All these en-zymes would have evolved from a common ancestorand they play a critical role in the absorption andmetabolism of lipids and lipoproteins. Lipases arewater-soluble enzymes that hydrolyse ester bonds ofwater-insoluble substrates such as triglycerides,phospholipids andcholesteryl esters (Wong & Schotz2002; Mukherjee2003).Mammalian mature LPL is a glycoprotein that isprimarily synthesized in adipocytes, muscle cells,macrophages and lactating mammary gland, butnot in the adult liver (Wion, Kirchgessner, Lusis,Schotz & Lawn 1987; Raisonnier, Etienne, Arnault,Brault, Noe, Chuat & Galibert1995).The human LPLgeneencoded475aminoacids,includinga27aminoacid signal peptide.The mature LPL protein consistsof 448 amino acids with a molecular weight of55kDa after resecting the signal peptide (Wong &Schotz2002).Theenzymeisactiveasanon-covalenthomodimerandisboundtothesurfaceofendothelialcells via glycosaminoglycans, from where it can bereleased byheparin (Mead, Irvine & Ramji 2002). Li-poprotein lipase plays a key role in lipid metabolismby hydrolysing triglycerides from chylomicrons andvery low-density lipoproteins (VLDL) to non-esteri-¢ed fatty acids and 2-monoacylglycerol, which areutilized either for storage or for energy production(Wang, Hartsuck& McConathy1992).The abnormal

Complete mitochondrial genome plays an important role in the accurate revelation of phylogenetic relationships among metazoans. Here we present the complete mitochondrial genome sequence from a sea cucumber Apostichopus japonicus (Echinodermata: Holothuroidea), which is the first representative from the subclass Aspidochirotacea. The mitochondrial genome of A. japonicus is 16,096 bp in length. The heavy strand consists of 31.8% A, 20.2% C, 17.9% G, and 30.1% T bases (AT skew = 0.027: GC skew = 0.062). It contains thirteen protein-coding genes (PCGs), twenty-two transfer RNA genes, and two ribosomal RNA genes. There are a total of 3793 codons in all thirteen mitochondrial PCGs, excluding incomplete termination codons. The most frequently used amino acid is Leu (15.77%), followed by Set (9.73%), Met (8.62%), Phe (7.94%), and Ala (7.28%). Intergenetic regions in the mitochondrial genome of A. japonicus are 839 bp in total, with three relatively large regions of Unassigned Sequences (UAS) greater than 100 bp. The gene order of A. japonicus is identical to that observed in the five studied sea urchins, which confirms that the gene order shared by the two classes (Holothuroidea and Echinoidea) is a ground pattern of echinoderm mitochondrial genomes. Bayesian tree based on the cob gene supports the following relationship: (outgroup, (Crinoids, (Asteroids, Ophiuroids, (Echinoids, Holothuroids)))). (C) 2009 Elsevier B.V. All rights reserved.

An autonomous mobile metal detector is designed, which can move on the ground actively. The system implements the function of data acquisition and signal conversion by LDC1000 module. High performance controller TM4C123BH6PGEI is served as the control core and a smart car is used to realize independent mobile function. The results empirically show that the metal detector can detect metal objects accurately, and the autonomous mobile function can reduce the labor cost greatly.

The complete mitochondrial genome of Coelomactra antiquata (Guangxi, in China, GX) was determined. It is 16 801 bp in length and is the first representative from this province. The mitochondrial genome encodes 35 genes, including 12 PCGs, two ribosomal RNA, and 21 transfer RNA genes. Atp8 and trnSer(UCN) genes are missing, compared with the typical gene content of animal mitochondrial genomes. Three (cob, nad1, nad4, and nad6) of the 12 PCGs in the mitochondrial genome initiate with the ATA, while other PCGs start with ATG. Two PCGs (atp6 and nad4L) end with incomplete stop codons (T-), and the remaining ones have complete stop codons (TAA or TAG). The largest non-coding region of the C. antiquata (GX) contains one section of tandem repeats (5 × 99 bp). Among all PCGs and rRNAs, the nad5 gene contains the maximum polymorphic sites (430), followed by nad4 (261) and cox2 (240). Two ribosomal RNA genes (srRNA and lrRNA) and cox1 are most conservative. The proportions of polymorphic sites in six genes (nad4, nad2, nad6, nad5, cox2, and nad3) are more than 20% (ranging from 20.25% to 25.21%). These high variable genes can be used as molecular markers in the population genetic analysis of the species.

A general formulation for developing reproducing kernel (RK) interpolation is presented. This is based on the coupling of a primitive function and an enrichment function. The primitive function introduces discrete Kronecker delta properties, while the enrichment function constitutes reproducing conditions. A necessary condition for obtaining a RK interpolation function is an orthogonality condition between the vector of enrichment functions and the vector of shifted monomial functions at the discrete points. A normalized kernel function with relative small support is employed as the primitive function. This approach does not employ a finite element shape function and therefore the interpolation function can be arbitrarily smooth. To maintain the convergence properties of the original RK approximation, a mixed interpolation is introduced. A rigorous error analysis is provided for the proposed method. Optimal order error estimates are shown for the meshfree interpolation in any Sobolev norms. Optimal order convergence is maintained when the proposed method is employed to solve one-dimensional boundary value problems. Numerical experiments are done demonstrating the theoretical error estimates. The performance of the method is illustrated in several sample problems. Copyright © 2003 John Wiley & Sons, Ltd.

Interest in meshfree (or meshless) methods has grown rapidly in recent years in solving boundary value problems (BVPs) arising in mechanics, especially in dealing with difficult problems involving large deformation, moving discontinuities, etc. In this paper, we provide a theoretical analysis of the reproducing kernel particle method (RKPM), which belongs to the family of meshfree methods. One goal of the paper is to set up a framework for error estimates of RKPM. We introduce the concept of a regular family of particle distributions and derive optimal order error estimates for RKP interpolants on a regular family of particle distributions. The interpolation error estimates can be used to yield error estimates for RKP solutions of BVPs.

Mactra veneriformis (Bivalvia: Mactridae) is one commonly cultured bivalve species in the western Pacific Ocean. In the current study, the complete mitrochondrial DNA (mtDNA) of the clam M. veneriformis was determined. The M. veneriformis mt genome is 16,854 bp in length and encodes 34 genes on the same strand, including 12 protein-coding genes (PCGs), 2 ribosomal RNA genes and 20 transfer RNA genes. The length of 12 PCGs is 11,358 bp, which accounts for 67.4% in whole mt genome. The proportion is similar to other clams' mt genomes and within those of bivalves mt genomes. Gene order (which is the same as that of RZ C. antiquata) of M. veneriformis mt genome is compared with that of other veneroids. Compared with the typical gene content of animal mt genomes, atp8 and two tRNA(Ser) genes are missing in the mt genome. All non-coding regions are 1978 bp in length, among them the longest one is speculated as the control region, which is located between the tRNA(His) and tRNA(Arg). The secondary largest non-coding region (NCR(664)) between the tRNA(Gln) and tRNA(Thr) in the M. veneriformis mt genome contains one section of tandem repeats (125 nt × 5.2 or 249 nt × 2.6). The tandem repeats account for 97.89% (650/664) of the NCR(664), which is a unique characteristic of the M. veneriformis mt non-coding regions compared with those of other veneroids.

The mitochondrial genome sequence of Coelomactra antiquata (Mollusca: Bivalvia) in Zhangzhou (zz-mtDNA) was fully sequenced and compared with that in Rizhao (rz-mtDNA) in this study. A tRNA (tRNA (Met) ) located between tRNA (Ala) and cox1 genes was identified in zz-mtDNA but not in rz-mtDNA. The largest non-coding region (NCR; MNR) contained 11 copies 99nt tandem repeat sequences exclusively in rz-mtDNA, while the second largest NCR with 400 bp between tRNA (Ala) and tRNA (Met) in zz-mtDNA was absent in rz-mtDNA. Secondary structures of ZZ and RZ C. antiquata rRNAs are significantly different. The mitochondrial genomic characteristics clearly indicate that there are at least two subspecies in C. antiquata.

Next-generation sequencing (NGS) has proven a valuable platform for fast and easy obtaining of large numbers of sequences at relatively low cost. In this study we use shot-gun sequencing method on Illumina HiSeq 2000, to obtain enough sequences for the assembly of the bryozoan Membranipora grandicella (Bryozoa: Cheilostomatida) mitochondrial genome, which is the first representative of the suborder Malacostegina. The complete mitochondrial genome is 15,861 bp in length, which is relatively larger than other studied bryozoans. The mitochondrial genome contains 13 protein-coding genes, 2 ribosomal RNAs and 20 transfer RNAs. To investigate the phylogenetic position and the inner relationships of the phylum Bryozoa, phylogenetic trees were constructed with amino acid sequences of 11 PCGs from 30 metazoans. Two superclades of protostomes, namely Lophotrochozoa and Ecdysozoa, are recovered as monophyletic with strong support in both ML and Bayesian analyses. Somewhat to surprise, Bryozoa appears as the sister group of Chaetognatha with moderate or high support. The relationship among five bryozoans is Tubulipora flabellaris + (M. grandicella + (Flustrellidra hispida + (Bugula neritina + Watersipora subtorquata))), which supports for the view that Cheilostomatida is not a natural, monophyletic clade. NGS proved to be a quick and easy method for sequencing a complete mitochondrial genome.

The complete mitochondrial genome plays an important role in the accurate inference of phylogenetic relationships among metazoans. Mactridae, also known as trough shells or duck clams, is an important family of marine bivalve clams in the order Veneroida. Here we present the complete mitochondrial genome sequence of the Xishishe Coelomactra antiquata (Mollusca: Bivalvia), which is the first representative from the family Mactridae. The mitochondrial genome of C. antiquata is of 17,384 bp in length, and encodes 35 genes, including 12 protein-coding, 21 transfer RNA, and 2 ribosomal RNA genes. Compared with the typical gene content of animal mitochondrial genomes, atp8 and tRNAS2 are missing. Gene order of the mitochondrial genome of C. antiquata is unique compared with others from Veneroida. In the mitochondrial genome of the C. antiquata, a total of 2189 bp of non-coding nucleotides are scattered among 26 non-coding regions. The largest non-coding region contains one section of tandem repeats (99 bp × 11), which is the second largest tandem repeats found in the mitochondrial genomes from Veneroida. The phylogenetic trees based on mitochondrial genomes support the monophyly of Veneridae and Lucinidae, and the relationship at the family level: ((Veneridae + Mactridae) + (Cardiidae + Solecurtidae)) + Lucinidae. The phylogenetic result is consistent with the morphological classification. Meanwhile, bootstrap values are very high (BP = 94–100), suggesting that the evolutionary relationship based on mitochondrial genomes is very reliable.

The complete mitochondrial sequence of the Japanese threadfin bream, Nemipterus japonicus has been determined. The circle genome is 16,995 bp in size, and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition of N. japonicus was similar to that of most other teleosts. The base composition of H-strand is 28.11% (A), 28.02% (T), 16.64 % (G) and 27.24 % (C), with an AT content of 56.12%. All genes are encoded on the heavy strand with the exception of ND6 and eight tRNA genes. The mitochondrial genome of N. japonicus presented will be in favor of resolving phylogenetic relationships within the family Nemipteridae and the Perciformes.

The complete mitochondrial sequence of the redeye mullet Liza haematocheila has been determined. The circle genome is 16,822 bp in size, and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition of L. haematocheila was similar to that of most other teleosts. The base composition of H-strand is 26.42% (A), 26.38% (T), 16.72% (G) and 30.47% (C), with an AT content of 52.8%. All genes are encoded on the heavy strand with the exception of ND6 and eight tRNA genes. The mitochondrial genome of L. haematocheila presented will be in favor of resolving phylogenetic relationships within the family Scatophagidae and the Mugiliformes.

A full-length cDNA coding lipoprotein lipase (LPL) was cloned from liver of adult common carp (Cyprinus carpio Var. Jian) by RT-PCR and rapid amplification of cDNA ends (RACE) approaches. The cDNA obtained was 2,411 bp long with a 1,524 bp open reading frame (ORF) encoding 507 amino acids. This amino acid sequence contains two structural regions: N-terminus (24-354 residues) and C-terminus (355-507 residues). Before N-terminus, 1-23 residues is signal peptide, 6-23 residues is transmembrance helix. At N-terminus, some conversed functional sites were found, including two N-linked glycosylation sites Asn(41) and Asn(88); one catalytic triad Ser(174), Asp(198) and His(283); one conserved heparin-binding site Arg(321) to Arg(324) (RKNR); eight cysteines residues Cys(69) and Cys(82), Cys(258) and Cys(281), Cys(306) and Cys(325), Cys(317) and Cys(320) which are involved in four disulfide bridges; one polypeptide "lid" that participates in substrate specificity. At C-terminus, Asn(401) is another N-linked glycosylation site, and Trp(434) and Trp(435) (WW) is lipid-binding site. The amino acid sequence has a high similarity, and shows similar structural features to LPL of other species. Tissue distribution of LPL mRNA in liver, head kidney, mesenteric adipose tissue, heart and white muscle of common carp was analyzed by semi-quantitative RT-PCR method using beta-actin gene as internal control. The result showed that the expressions of LPL mRNA were detected in all examined tissues of common carp. The expression levels of LPL in the mesenteric adipose tissue was highest among these tissues, following in liver and head kidney, and the lowest expression was found in heart and white muscle.

The first and second internal transcribed spacer (ITS1 and ITS2) regions of the ribosomal DNA from four species, Meretrix meretrix L., Cyclina sinensis G., Mercenaria mercenaria L., and Protothaca jedoensis L., belonging to the family Veneridae were amplified by PCR and sequenced. The size of the ITS1 PCR amplification product ranged from 663 bp to 978 bp, with GC contents ranging from 60.78% to 64.97%. The size of the ITS1 sequence ranged from 585 bp to 900 bp, which is the largest range reported thus far in bivalve species, with GC contents ranging from 61.03% to 65.62%. The size of the ITS2 PCR amplification product ranged from 513 bp to 644 bp, with GC contents ranging from 61.29% to 62.73%. The size of the ITS2 sequence ranged from 281 bp to 412 bp, with GC contents ranging from 65.21% to 67.87%. Extensive sequence variation and obvious length polymorphisms were noted for both regions in these species, and sequence similarity of ITS2 was higher than that of ITS1 across species. The complete sequences of 5.8S ribosomal RNA gene were obtained by assembling ITS1 and ITS2 sequences, and the sequence length in all species was 157 bp. The phylogenetic tree of Veneridae clams was reconstructed using ITS2-containing partial sequences of both 5.8S and 28S ribosomal DNA as markers and the corresponding sequence information in Arctica islandica as the outgroup. Tree topologies indicated that P. jedoensis shared a close relationship with M. mercenaria and C. sinensis, a distant relationship with other species.

With laboratory experiments, this paper studied the oxygen consumption rate (OCR) and ammonia-N excretion rate (NR) of Coelomactra antiquata at different levels of dissolved oxygen (DO) and water temperature. The results indicated that at 25 degrees C and 3.11 +/- 0.15 mg DO x L(-1), C. antiquate had a comparatively stable OCR and NR, which maintained at 0.74 +/- 0.05 mg x g(-1) x h(-1) and 2.56 +/- 0.05 micromol x g(-1) x h(-1), respectively. When DO was lower than 3.11 +/- 0.15 mg x L(-1), the metabolism of C. antiquate became abnormal, and its OCR was decreased with decreasing DO until suffocate, with a suffocate point 1.22 +/- 0.06 mg L(-1) at 25 degrees C. The NR also declined with decreasing DO, which ceased later than oxygen consumption. There was a quadratic linear relationship between OCR and water temperature (OCR = -0.0027T(2) + 0.1367T - 0.9557, R2 = 0.9724). When water temperature was 25.3 degrees C, the OCR arrived to its maximum value 0.77 mg x g(-1) x h(-1). The O/N ratio at optimal temperature (15-20 degrees C) was higher than that at low (10 degrees C) and high temperature (25 degrees C and 30 degrees C). To maintain its standard metabolism, C. antiquata consumed more fat under fit condition, while more protein under stress.

The complete mitochondrial sequence of the spotted scat Scatophagus argus has been determined using long amplification polymerase chain reaction (LA-PCR). The total length of sequence is 16,778 bp, and includes 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 control region. The base composition of H-strand is 27.23% (A), 27.54% (T), 16.22% (G) and 28.81% (C), with an AT content of 55.08%. The arrangement of genes in S. argus is identical to that of other fish species. All genes are encoded on the heavy strand with the exception of ND6 and eight tRNA genes. The mitochondrial genome of S. argus presented here will contribute to resolve phylogenetic relationships within the family Scatophagidae and the Perciformes.