Comparative Analysis of Four Complete Mitochondrial Genomes of Epinephelidae (Perciformes).

Groupers are commercial, mainly reef-associated fishes, classified in the family Epinephelidae (Perciformes). This study first sequenced the complete mitogenomes of Cephalopholis leopardus, Cephalopholis spiloparaea, Epinephelus amblycephalus, and Epinephelus hexagonatus. The lengths of the four Epinephelidae mitogenomes ranged from 16,585 base pair (bp) to 16,872 bp with the typical gene order. All tRNA genes had a typical cloverleaf structure, except the tRNA-Ser (AGY) gene which was lacking the entire dihydrouridine arm. The ratio of nonsynonymous substitution (Ka) and synonymous substitution (Ks) indicated that four groupers were suffering a purifying selection. Phylogenetic relationships were reconstructed by Bayesian inference (BI) and maximum likelihood (ML) methods based on all mitogenomic data of 41 groupers and 2 outgroups. The identical topologies result with high support values showed that Cephalopholis and Epinephelus are not monophyletic genera. Anyperodon and Cromileptes clustered to Epinephelus. Aethaloperca rogaa and Cephalopholis argus assembled a clad. Cephalopholis leopardus, C. spiloparaea, and Cephalopholis miniata are also in a clade. Epinephelushexagonatus is close to Epinephelus tauvina and Epinephelus merra, and E. amblycephalus is a sister group with Epinephelus stictus. More mitogenomic data from Epinephelidae species are essential to understand its taxonomic status with the family Serranidae.

A simple approach for an optically transparent nanochannel device prototype.

Compared with microfluidic devices, the fabrication of structure-controllable and designable nanochannel devices has been considered to have high costs and complex procedures, which require expensive equipment and high-quality raw materials. Exploring fast, simple and inexpensive approaches in nanochannel fabrication will be greatly helpful to speed up laboratory studies of nanofluidics. Here we developed a simple and inexpensive approach to fabricate a nanochannel device with a glass/epoxy resin/glass structure. The grooves were engraved using a UV laser on an aluminum sacrificial layer on the substrate glass, and epoxy resin was coated on the substrate and stuffed fully into the grooves. Another glass plate with holes for fluidic inlets and outlets was bonded on the top of the resin layer. The nanochannels were formed by etching thin sacrificial layers electrochemically. Meanwhile, the microstructures of the fluidic outlets and inlets could be fabricated simultaneously to the nanochannel formation. The total processing time for the simple nanochannel device took less than 10 hours. Optically transparent nanochannels with a depth of up to 20 nm were achieved. Nanofluidic behaviors in the nanochannels were observed under both optical and fluorescence microscopes.