The mitochondrial genome of Bottapotamon fukienense (Brachiura: Potamidae) is fragmented into two chromosomes.

BACKGROUND: China is the hotspot of global freshwater crab diversity, but their wild populations are facing severe pressures associated with anthropogenic factors, necessitating the need to map their taxonomic and genetic diversity and design conservation policies. RESULTS: Herein, we sequenced the mitochondrial genome of a Chinese freshwater crab species Bottapotamon fukienense, and found that it is fragmented into two chromosomes. We confirmed that fragmentation was not limited to a single specimen or population. Chromosome 1 comprised 15,111 base pairs (bp) and there were 26 genes and one pseudogene (pseudo-nad1) encoded on it. Chromosome 2 comprised 8,173 bp and there were 12 genes and two pseudogenes (pseudo-trnL2 and pseudo-rrnL) encoded on it. Combined, they comprise the largest mitogenome (23,284 bp) among the Potamidae. Bottapotamon was the only genus in the Potamidae dataset exhibiting rearrangements of protein-coding genes. Bottapotamon fukienense exhibited average rates of sequence evolution in the dataset and did not differ in selection pressures from the remaining Potamidae. CONCLUSIONS: This is the first experimentally confirmed fragmentation of a mitogenome in crustaceans. While the mitogenome of B. fukienense exhibited multiple signs of elevated mitogenomic architecture evolution rates, including the exceptionally large size, duplicated genes, pseudogenisation, rearrangements of protein-coding genes, and fragmentation, there is no evidence that this is matched by elevated sequence evolutionary rates or changes in selection pressures.

Adaptive evolution characteristics of mitochondrial genomes in genus Aparapotamon (Brachyura, Potamidae) of freshwater crabs.

BACKGROUND: Aparapotamon, a freshwater crab genus endemic to China, includes 13 species. The distribution of Aparapotamon spans the first and second tiers of China's terrain ladder, showing great altitudinal differences. To study the molecular mechanisms of adaptive evolution in Aparapotamon, we performed evolutionary analyses, including morphological, geographical, and phylogenetic analyses and divergence time estimation. We sequenced the mitogenomes of Aparapotamon binchuanense and Aparapotamon huizeense for the first time and resequenced three other mitogenomes of Aparapotamon grahami and Aparapotamon gracilipedum. These sequences were combined with NCBI sequences to perform comparative mitogenome analysis of all 13 Aparapotamon species, revealing mitogenome arrangement and the characteristics of protein-coding and tRNA genes. RESULTS: A new species classification scheme of the genus Aparapotamon has been detected and verified by different aspects, including geographical, morphological, phylogenetics and comparative mitogenome analyses. Imprints from adaptive evolution were discovered in the mitochondrial genomes of group A, including the same codon loss at position 416 of the ND6 gene and the unique arrangement pattern of the tRNA-Ile gene. Multiple tRNA genes conserved or involved in adaptive evolution were detected. Two genes associated with altitudinal adaptation, ATP8 and ND6, which experienced positive selection, were identified for the first time in freshwater crabs. CONCLUSIONS: Geological movements of the Qinghai-Tibet Plateau and Hengduan Mountains likely strongly impacted the speciation and differentiation of the four Aparapotamon groups. After some group A species dispersed from the Hengduan Mountain Range, new evolutionary characteristics emerged in their mitochondrial genomes, facilitating adaptation to the low-altitude environment of China's second terrain tier. Ultimately, group A species spread to high latitudes along the upper reaches of the Yangtze River, showing faster evolutionary rates, higher species diversity and the widest distribution.

Highly active iron-nitrogen-boron-carbon bifunctional electrocatalytic platform for hydrogen peroxide sensing and oxygen reduction.

An iron-nitrogen-boron-carbon (Fe-N-B-C) bifunctional electrocatalyst was prepared by means of a facile one-step hydrothermal reduction of graphene oxide using dimethylamine borane as doping agent. In addition, hemins were efficiently anchored during doping/reducing process on this modified graphene. The as-prepared Fe-N-B-C electro-catalyst showed enhanced response as regards its potential for reduction of H2O2 and O2. In view of its catalytic activity, this Fe-N-B-C material was tested for the determination of H2O2 with a chronoamperometry method, obtaining a detection limit as low as 0.055 µM, which is better than that of some Hemin-N-C materials. Regarding O2 reduction reaction, a study performed using a rotating disk electrode indicated that this material exhibits a positive onset potential (0.90V vs. RHE), high selectivity (4e- process), high limiting-current density (4.75 mA cm-2) and strong resistance against the crossover-effect from methanol in alkaline medium, making it to be the promising candidate as alternative for commercial Pt/C catalysts. These results could have commercial and environmental relevance and would deserve further complementary investigation.

Neurotransmitter and neuropeptide regulation of mast cell function: a systematic review.

The existence of the neural control of mast cell functions has long been proposed. Mast cells (MCs) are localized in association with the peripheral nervous system (PNS) and the brain, where they are closely aligned, anatomically and functionally, with neurons and neuronal processes throughout the body. They express receptors for and are regulated by various neurotransmitters, neuropeptides, and other neuromodulators. Consequently, modulation provided by these neurotransmitters and neuromodulators allows neural control of MC functions and involvement in the pathogenesis of mast cell-related disease states. Recently, the roles of individual neurotransmitters and neuropeptides in regulating mast cell actions have been investigated extensively. This review offers a systematic review of recent advances in our understanding of the contributions of neurotransmitters and neuropeptides to mast cell activation and the pathological implications of this regulation on mast cell-related disease states, though the full extent to which such control influences health and disease is still unclear, and a complete understanding of the mechanisms underlying the control is lacking. Future validation of animal and in vitro models also is needed, which incorporates the integration of microenvironment-specific influences and the complex, multifaceted cross-talk between mast cells and various neural signals. Moreover, new biological agents directed against neurotransmitter receptors on mast cells that can be used for therapeutic intervention need to be more specific, which will reduce their ability to support inflammatory responses and enhance their potential roles in protecting against mast cell-related pathogenesis.

The systematic position of Cryptopotamonanacoluthon (Kemp, 1918), with the description of a new species of Sinolapotamon Tai & Sung, 1975 (Crustacea, Decapoda, Brachyura, Potamidae) from southern China.

The systematics of the potamid freshwater crab Cryptopotamonanacoluthon (Kemp, 1918) is clarified, and its generic position in Sinolapotamon Tai & Sung, 1975, is confirmed based on morphological comparisons, geographical information and phylogenetic analyses. A new species of Sinolapotamon, Sinolapotamoncirratumsp. nov. is described from the Guangxi Zhuang Autonomous Region of China. Sinolapotamoncirratumsp. nov. is distinguished from its congeners by the combination of characters of its carapace, third maxilliped, anterolateral margin, and unique male first gonopod. Phylogenetic analyses based on partial COX1, 16S rRNA and 28S rRNA genes also support the species as new.

A new species of freshwater crab of the genus Nanhaipotamon Bott, 1968 (Crustacea, Decapoda, Brachyura, Potamidae) from Longhai, Fujian Province, China.

A new species of freshwater crab of the genus Nanhaipotamon Bott, 1968 is described from Xiaye Village, Chengxiang Town, Longhai County, Zhangzhou City, Fujian Province, China. The new species is distinguished from congeners by the combination of characters of its carapace, third maxilliped, unequal chelipeds, triangular male abdomen and unique male first gonopod. Molecular evidence derived from partial mitochondrial 16S rRNA and COI genes also support the species as new.

Two new species of freshwater crab of the genus Aparapotamon Dai & Chen, 1985 (Crustacea, Brachyura, Potamidae) from Yunnan, China.

Two new species of freshwater crab of the genus Potamid Aparapotamon Dai & Chen, 1985 are described from Yunnan Province, southwest China. Morphological comparisons were made between the two new species and type materials of other 11 species of Aparapotamon. Aparapotamonbinchuanense sp. nov. and A.huizeense sp. nov. can be separated from their congeners by the shape of the epibranchial tooth, the frontal view of the cephalothorax, the male first gonopod, and the female vulvae. The molecular analyses based on partial mitochondrial 16S rRNA gene are also included. This study brings the number of Aparapotamon species to 13.

The complete mitochondrial genome of the freshwater crab Tenuilapotamon latilum kaiyangense Dai et Li,1985 (Decapoda: Brachyura: Potamoidea).

We first reported the complete mitochondrial genome of Tenuilapotamon latilum kaiyangense (Decapoda: Brachyura: Potamoidea). The genome is 19,294 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. The whole mitochondrial genome is characterized by the apparent AT bias (74.19%). This research provides DNA data for further researches on population genetics and phylogenetics.

The complete mitochondrial genome of the freshwater crab Bottapotamon lingchuanense Türkay and Dai 1997 (Decapoda: Brachyura: Potamoidea).

We report the complete mitochondrial genome of Bottapotamon lingchuanense for the first time, which is found to be 17,612 base pairs in length, and contains 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA), and 1 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 B. lingchuanense is the first mitochondrial genome under the genus Bottapotamon, providing DNA data for species identification, enriching the species diversity of Brachyura. The maximum-likelihood (ML) tree and Bayesian inference (BI) tree based on the 13 PCGs of mitochondrial genome of Brachyura species showed similar topologies with high confidence, and the analysis results were consistent with the current mainstream classification system. The results indicating that B. lingchuanense is closely related to Neilupotamon sinense, Sinopotamon, and Tenuilapotamon, and it is likely to be derived from them.

Paragonimus and its hosts in China: An update.

Paragonimiasis is an important foodborne parasitic disease. Over 50 species of Paragonimus have been reported worldwide, and China has the widest distribution and largest number of species. The detection of Paragonimus metacercariae from second intermediate hosts has been reported in 22 provinces and municipalities. The most frequently reported species are P. westermani, P. skrjabini, P. heterotremus and Euparagonimus cenocopiosus. In this review, we collected and reviewed relevant reports on the detection of Paragonimus metacercariae in second intermediate hosts from 1937 to 2020 from all areas of China. We provide an updated and current summary of Paragonimus species and their hosts in China. Data on the geographical range, species distribution, and second intermediate host species of Paragonimus were extracted. ArcGIS10.2 software was used to generate distribution maps of Paragonimus for four time periods: 1937-1990, 1991-2005, 2006-2020 and 1937-2020. We analyzed the geographic and spatiotemporal dynamics of Paragonimus prevalence in natural foci and provided a basis for further research and paragonimiasis prevention strategies in China.

Description of two new species of the genus Heterochelamon Türkay & Dai, 1997 (Crustacea: Decapoda: Brachyura: Potamidae), from southern China.

This study describes two new species of freshwater crab of the genus Heterochelamon Türkay & Dai, 1997 from southern China, H. huidongense from Guangdong Province and H. jinxiuense from Guangxi Zhuang Autonomous Region. The two new species can be differentiated from congeners by characters derived from the shape of the epibranchial tooth, external orbital angle, cheliped proportions and structure of the male first gonopod. The present study brings the number of Heterochelamon species to seven. We used the mitochondrial 16S rRNA gene for a molecular analysis and the results are consistent with the morphological features that support the recognition of two new taxa.

A new species of freshwater crab of the genus Qianguimon Huang, 2018 (Decapoda: Brachyura: Potamidae) from Guangxi, Southern China.

A new species of freshwater crab of the genus Qianguimon Huang, 2018, is described from Guangxi Zhuang Autonomous Region, southern China. It can be distinguished from congeners by the following characters: male first gonopods bent inward at about 45° at base of terminal segment, carapace regions distinct and rugged and the female vulva opening inwards and downwards. In addition, molecular evidence derived from the 16S rRNA gene supported the species described in this study as a new species of Qianguimon.

Influence of Surface Oxygen Vacancies and Ruthenium Valence State on the Catalysis of Pyrochlore Oxides.

Proton exchange membrane (PEM) water electrolysis is a promising energy storage solution by electrochemically splitting water into hydrogen fuel and oxygen. However, the sluggish kinetics, high operating potential, and corrosive acidic environment during the oxygen evolution reaction (OER) require the use of scarce and costly Ir-based oxides, tremendously hampering its large-scale commercialization. Hence, developing active and stable anode catalysts with reduced precious-metal usage is desperately essential. For the first time, we report a group of Y2-xBaxRu2O7 pyrochlore oxides and employ them in acid OER and PEM electrolyzers. We reveal the mechanism for the promoted OER performance of Ba-doped Y2Ru2O7 in which partially replacing Y3+ by Ba2+ in Y2Ru2O7 greatly facilitates the hole-doping effect, which generates massive oxygen vacancy and multivalence of Ru5+/Ru4+, thus boosting the OER performance of Y2-xBaxRu2O7. This work provides an effective method and paradigm for improving the electrocatalytic property of pyrochlore oxides.

The complete mitochondrial genome of the freshwater crab Potamiscus motuoensis (Decapoda: Brachyura: Potamoidea).

Potamiscus motuoensis is the only one freshwater crab species distributed in Yarlung Zangbo River Grand Canyon and its complete mitochondrial genome was obtained for the first time. The complete mitochondrial genome of P. motuoensis is 17,971 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. In addition, the mitogenome has 19 noncoding regions ranging from 1 to 1396 bp in length. The report of the mitochondrial genome will enrich the species diversity of Yarlung Zangbo River Grand Canyon and provide data support for further research.

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.

The complete mitochondrial genome of the freshwater crab Neilupotamon xinganense (Decapoda: Brachyura: Potamoidea).

In this study, we first obtained the complete mitochondrial genome of Neilupotamon xinganense (Decapoda: Brachyura: Potamoidea). The genome is 16,965 bp in length and typically consists of 37 genes (13 protein-coding genes, 22 tRNAs genes, two rRNAs genes, and one putative control region). In addition, the mitogenome has 20 non-coding regions ranging from 1 to 683 bp in length. This study provides DNA data for further researches on population genetics and phylogenetics.

A new species of freshwater crab of the genus Mediapotamon Türkay & Dai, 1997 (Crustacea, Decapoda, Brachyura, Potamidae) from Guizhou, China.

A new species of Mediapotamon Türkay & Dai, 1997 from a karst system in southwest China is described. The new species can be separated from congeners by the combination of a sharp and distinct epibranchial tooth, the anterolateral region lined with few scattered granules, the terminal segment of the male first gonopod distinctly bent with a constant diameter, and the position of the female vulvae. Mitochondrial 16S rDNA genetic data was used to investigate the systematic position of the new species, which is supported as a new taxon.

Description of A New Species of Freshwater Crab of the Genus Qianguimon Huang, 2018 (Crustacea: Decapoda: Brachyura: Potamidae) from Yulin, Guangxi, Southern China.

A new species of freshwater crab of the genus Qianguimon Huang, 2018, Q. rongxianense sp. nov., is described from Rong County, Yulin City, Guangxi Zhuang Autonomous region, southern China. This new species resembles its congeners and some species in the genus Yarepotamon Dai & Türkay, 1997, but can be distinguished from these by its combination of the carapace, third maxilliped, male gonopod, female vulvae characters and size. Molecular data derived from the mitochondrial 16S rDNA supports the establishment of the new species, but does not provide further evidence as to its generic placement.

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.

The complete mitochondrial genome of Aparapotamon similium (Decapoda: Brachyura), an endemic to China.

In this study, we first obtained the complete mitochondrial genome of Aparapoamon similium (Decapoda: Brachyura). The complete mitochondrial genome is 19,236 bp in length and includes 37 typical genes (13 protein-coding genes, 22 tRNAs genes, 2 rRNAs genes, and 1 putative control region). The whole mitochondrial genome is characterized by the apparent AT bias (72.82%). BI and ML phylogenetic analysis based on 67 mitochondrial genomes of Brachyura species show a highly similar topology structure with high bootstrap supported. The results reveal the close relationship between A. similium and Potamiscus motuoense. This study would establish a solid data foundation for further diversification studies.