The complete mitochondrial genome of the freshwater crab Chinapotamon maolanense (Decapoda: Brachyura: Potamoidea).

The complete mitochondrial genome of Chinapotamon maolanense was obtained for the first time. The complete mitochondrial genome of C. maolanense is 17,130 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. In addition, the mitogenome has 18 noncoding regions ranging from 1 to 1553 bp in length.

Two new species and the molecular phylogeography of the freshwater crab genus Bottapotamon (Crustacea: Decapoda: Brachyura: Potamidae).

Bottapotamon chenzhouense sp. n. and B. luxiense sp. n. are described from Hunan Province and Jiangxi Province, respectively. These species both have diagnostic features of the genus Bottapotamon and discernible characteristics as new species. B. chenzhouense sp. n. can be distinguished from co-geners by features such as the G1, which has a fold covering the surface of the entire subterminal article with a distal region. B. luxiense sp. n. has an elliptical carapace, and a sturdy and blunt terminal article of G1. The molecular phylogeny and biogeography of the genus Bottapotamon (Decapoda: Brachyura: Potamidae) were studied, using mitochondrial cytochrome oxidase I (mtDNA COI), 16S rRNA and nuclear histone H3 gene fragments. The results support the assignment of the two new species to the genus Bottapotamon. In addition, the divergence time of the genus Bottapotamon was estimated to be 3.49-1.08 Ma, which coincided with various vicariant and dispersal events that occurred in the geological area where the genus Bottapotamon is commonly distributed. Mountains appear to have played an important role in the distribution of this genus. The Wuyi Mountains gradually formed offshore and inland of southeastern China by the compression of the Pacific plate and the Indian plate in the Neogene-Quaternary, and the Luoxiao Mountains formed continuously in the continued forming in the north-south direction because of neotectonic movement, have resulted in the geographical distribution pattern of the genus Bottapotamon, which was also established gradually.

Utilization of recombinase polymerase amplification combined with a lateral flow strip for detection of Perkinsus beihaiensis in the oyster Crassostrea hongkongensis.

BACKGROUND: Perkinsosis, a disease caused by the protist Perkinsus, is responsible for mass mortalities of many molluscan species worldwide. The rapid, early and accurate detection of Perkinsus infection is necessary to react to outbreaks, and manage disease transmission. Current methods for diagnosis of Perkinsus spp. are time-consuming or require professional equipment and experienced personnel, rendering them unsuitable for field application. Recombinase polymerase amplification (RPA) assay is a highly sensitive and selective isothermal amplification technique that operates at temperatures of 37-42 °C, requires minimal sample preparation, and is capable of amplifying as low as 1-10 target DNA copies in less than 20 minutes. METHODS: We report a novel RPA assay that amplifies the internal transcriber spacer (ITS) region of P. beihaiensis, which, followed by rapid detection of amplicons using a lateral flow (LF) strip, enables easy visualization of results by the naked eye. RESULTS: The LF-RPA assay successfully amplified P. beihaiensis DNA using a set of primers of 20-25 bp in length. After incubation at 37 °C for 25 min, results were read within 5 min by the naked eye on a lateral flow strip. Our LF-RPA assay was comparably sensitive to qPCR assay, and capable of detecting as few as 26 copies of P. beihaiensis DNA. Cross-amplification occurred with other two Perkinsus species, P. olseni and P. chesapeaki, but not with other potential pathogen taxa in culture environments. We compared the performance of LF-RPA, conventional PCR and qPCR assays on 60 oyster samples. While LF-RPA assay results were 86.2% as sensitive, 77.4% as specific, and generally in agreement with those of conventional PCR results, they were more (93.3%) sensitive, (86.7%) specific, and agreed better with qPCR assay results. Future research should focus on developing simple DNA extraction methods that do not require professional laboratories and complicated extraction procedures, to facilitate application of this LF-RPA assay in the field. CONCLUSIONS: Our LF-RPA assay provides a rapid and efficient method for detecting species of Perkinsus. This novel assay has potential to be used in field applications.

The complete mitochondrial genome of the freshwater crab Sinolapotamon patellifer (Decapoda: Brachyura: Potamoidea).

We report the complete mitochondrial genome of Sinolapotamon patellifer for the first time, which is found to be 16,547 base pairs in length, and contains 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA), and one non-coding AT-rich region known as the D-loop. In addition, the mitogenome has 17 intergenic regions ranging from 1 to 1512 bp in length. The mitochondrial genome of S. patellifer is the first mitochondrial genome under the genus Sinolapamon, providing DNA data for species identification, enriching the species diversity of Brachyura, and providing a basis for further studies on population genetics and phylogenetics.