First description study on molecular characterization of Hemiclepsis khankiana (Hirudinea: Glossiphoniidae) in China.

BACKGROUND: Leeches are an integral component of aquatic biocenosis and can be found in a wide range of ecosystems such as freshwater, saltwater, flowing, and still-water ecosystems. It especially plays an important role in the freshwater benthic community and is an important part of the food web. In this study, a leech species was found in the mantle cavity of wild freshwater mussels in Zigong City, Sichuan Province, China, and its identity was determined through morphological analysis and molecular biological analysis. RESULTS: The leech is Hemiclepsis khankiana, a new species of Hemiclepsis that has been discovered in Russia in recent years. Through morphological analysis, the current survey observed that the morphological characteristics of Hemiclepsis khankiana eyespots were significantly different from the first reported description. The first pair of eyespots on the leech were separated and clear, while it had been reduced to unclear shadows in the previous report. The phylogenetic tree based on the COI gene showed that the COI gene sequence obtained in this study was in the same evolutionary branch as Hemiclepsis khankiana (MN295420, MN295421). Genetically, it was most closely related to Hemiclepsis kasmiana (mean COI p-distance = 3.98%). CONCLUSIONS: The current study reported on the new distribution range of Hemiclepsis khankiana, which was initially discovered in China. This study indicates that the distribution range of the leech species has expanded, laying a foundation for further studies in China.

Prediction of sub-pyramid texturing as the next step towards high efficiency silicon heterojunction solar cells.

The interfacial morphology of crystalline silicon/hydrogenated amorphous silicon (c-Si/a-Si:H) is a key success factor to approach the theoretical efficiency of Si-based solar cells, especially Si heterojunction technology. The unexpected crystalline silicon epitaxial growth and interfacial nanotwins formation remain a challenging issue for silicon heterojunction technology. Here, we design a hybrid interface by tuning pyramid apex-angle to improve c-Si/a-Si:H interfacial morphology in silicon solar cells. The pyramid apex-angle (slightly smaller than 70.53°) consists of hybrid (111)0.9/(011)0.1 c-Si planes, rather than pure (111) planes in conventional texture pyramid. Employing microsecond-long low-temperature (500 K) molecular dynamic simulations, the hybrid (111)/(011) plane prevents from both c-Si epitaxial growth and nanotwin formation. More importantly, given there is not any additional industrial preparation process, the hybrid c-Si plane could improve c-Si/a-Si:H interfacial morphology for a-Si passivated contacts technique, and wide-applied for all silicon-based solar cells as well.

Composition engineering of perovskite absorber assisted efficient textured monolithic perovskite/silicon heterojunction tandem solar cells.

A two-terminal (2T) perovskite/silicon heterojunction tandem solar cell (PVSK/SHJ) is considered one of the most promising candidates for next-generation photovoltaics with the possibility of achieving a power conversion efficiency (PCE) exceeding 30% at low production cost. However, the current mismatch and voltage loss have seriously decreased the performance of 2T PVSK/SHJ tandem solar cells. Here, we report the composition engineering for perovskite top cells to prepare a high performance 2T tandem cell by tuning CsBr co-evaporating rates and increasing concentrations of FAI/FABr solutions. We show that the variation in composition for the perovskite absorber effectively optimized the band gap and diminished the defects of the top cell. Our investigations reveal that the current mismatch of sub-cells was carefully tuned by introducing CsBr at varied co-evaporating rates and the voltage loss was decreased by increasing concentrations of FAI/FABr solutions. Thus, we achieved a PCE of 23.22% in two-terminal monolithic tandems with an area of 1.2 cm2 by tuning the composition of the perovskite absorber.

Gut microbiota facilitates adaptation of the plateau zokor (Myospalax baileyi) to the plateau living environment.

Gut microbiota not only helps the hosts to perform many key physiological functions such as food digestion, energy harvesting and immune regulation, but also influences host ecology and facilitates adaptation of the host to extreme environments. Plateau zokors epitomize successful physiological adaptation to their living environment in the face of the harsh environment characterized by low temperature, low pressure and hypoxia in the Tibetan plateau region and high concentrations of CO2 in their burrows. Therefore, here we used a metagenomic sequencing approach to explore how gut microbiota contributed to the adaptive evolution of the plateau zokor on the Qinghai-Tibet Plateau. Our metagenomic results show that the gut microbiota of plateau zokors on the Tibetan plateau is not only enriched in a large number of species related to energy metabolism and production of short-chain fatty acids (SCFAs), but also significantly enriched the KO terms that involve carbohydrate uptake pathways, which well address energy uptake in plateau zokors while also reducing inflammatory responses due to low pressure, hypoxia and high CO2 concentrations. There was also a significant enrichment of tripeptidyl-peptidase II (TPPII) associated with antigen processing, apoptosis, DNA damage repair and cell division, which may facilitate the immune response and tissue damage repair in plateau zokors under extreme conditions. These results suggest that these gut microbiota and their metabolites together contribute to the physiological adaptation of plateau zokors, providing new insights into the contribution of the microbiome to the evolution of mammalian adaptation.

Molecular detection of Anaplasma spp., Babesia spp. and Theileria spp. in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibetan Plateau, China.

BACKGROUND: Anaplasma, Babesia and Theileria are tick-borne pathogens (TBPs) that affect livestock worldwide. However, information on these pathogens in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibet Plateau (QTP), China, is limited. In this study, Anaplasma spp., Babesia spp. and Theileria spp. infections were assessed in yaks and Tibetan sheep from Qinghai Province. METHODS: A total of 734 blood samples were collected from 425 yaks and 309 Tibetan sheep at nine sampling sites. Standard or nested polymerase chain reaction was employed to screen all the blood samples using species- or genus-specific primers. RESULTS: The results showed that 14.1% (60/425) of yaks and 79.9% (247/309) of Tibetan sheep were infected with at least one pathogen. Anaplasma ovis, Anaplasma bovis, Anaplasma capra, Anaplasma phagocytophilum, Babesia bovis and Theileria spp. were detected in this study, with total infection rates for all the assessed animals of 22.1% (162/734), 16.3% (120/734), 23.6% (173/734), 8.2% (60/734), 2.7% (20/734) and 19.3% (142/734), respectively. For yaks, the infection rate of A. bovis was 6.4% (27/425), that of B. bovis was 4.7% (20/425) and that of Theileria spp. was 3.3% (14/425). Moreover, 52.4% (162/309) of the Tibetan sheep samples were infected with A. ovis, 30.1% (93/309) with A. bovis, 56.0% (173/309) with A. capra, 19.4% (60/309) with A. phagocytophilum and 41.4% (128/309) with Theileria spp. CONCLUSIONS: This study revealed the prevalence of Anaplasma spp., Babesia spp. and Theileria spp. in yaks and Tibetan sheep in Qinghai Province, China, and provides new data for a better understanding of the epidemiology of TBPs in these animals in this area of the QTP, China.

Seroprevalence and Epidemiology of Toxoplasma gondii in Animals in the Qinghai-Tibetan Plateau Area, China.

Toxoplasma gondii belongs to the Apicomplexan protozoa-an obligate intracellular parasite-causing toxoplasmosis that has a worldwide distribution and is very harmful to both human health and the livestock industry. However, the information on toxoplasmosis in the Qinghai-Tibetan Plateau Area (QTPA) and the seroprevalence of T. gondii in the food-borne animals in that area has been limited. Therefore, this study focused to T. gondii and toxoplasmosis to perform an indirect ELISA test based on recombinant TgSAG2 protein to establish a comprehensive record of the seroprevalence of T. gondii infections in a wide range of animals, including Tibetan sheep (Ovis aries), yaks (Bos grunniens), cows, chicken, pigs, and horses, in the QTPA. Overall, the seropositive rates of the specific-T. gondii IgG and IgM antibodies in all investigated animals were 44.1% (1179/2673) and 18.0% (469/2612), respectively. The 14.9% (389/2612) sera were determined to be both IgG and IgM positive samples, 30.2% (789/2673) were single-IgG seropositive, and a total of 80 in 2612 animals (3.0%) were single-IgM seropositive. Moreover, for the animal species, the pig was the most prevalent animal (90.2%, 304/337) for IgG positivity, followed by Tibetan sheep (50.7%, 460/907), chickens (45.8%, 229/500), yaks (21.1%, 140/663), cows (18.5%, 38/205) and horses (13.1%, 8/61), respectively. For the IgM antibody positivity, the pig was also the most prevalent animal (41.8%, 141/337), followed by Tibetan sheep (21.2%, 191/907), cows (15.1%, 31/205), chickens (12.4%, 62/500) and yaks (6.6%, 44/663), respectively. The significant differences in the prevalent distribution of T. gondii were found in the different altitudes. In conclusion, this study found the high seroprevalence for T. gondii infections among these animal species in the QTPA, and provides new data to facilitate further research for development of control measures against T. gondii infections in the surveyed locations.

Spotted Fever Group Rickettsia Infecting Ticks (Acari: Ixodidae), Yak (Bos grunniens), and Tibetan Sheep (Ovis aries) in the Qinghai-Tibetan Plateau Area, China.

The Qinghai-Tibet Plateau Area (QTPA) has a complex natural ecosystem, causing a greatly increased risk of spreading various tick-borne diseases including rickettsial infections, which are regarded as one of the oldest known vector-borne zoonoses. However, the information of one of its pathogen, spotted fever group Rickettsia (SFG Rickettsia), is limited in tick vectors and animals in this area. Therefore, this study focused on the investigation of SFG Rickettsia in tick vectors, yaks (Bos grunniens), and Tibetan sheep (Ovis aries) in the QTPA. A total of 1,000 samples were collected from nine sampling sites, including 425 of yaks, 309 of Tibetan sheep, 266 of ticks. By morphological examination, PCR, and sequencing, we confirmed the species of all collected ticks. All tick samples, all yak and Tibetan sheep blood samples were detected based on SFG Rickettsia ompA and sca4 gene. The results showed that all tick samples were identified to be Haemaphysalis qinghaiensis, and the positive rates of SFG Rickettsia were 5.9% (25/425), 0.3% (1/309), and 54.1% (144/266) in yaks, Tibetan sheep, and ticks, respectively. All positive samples were sequenced, and BLASTn analysis of the ompA gene sequences of SFG Rickettsia showed that all positive samples from animals and ticks had 99.04-100% identity with yak and horse isolates from Qinghai Province, China. BLASTn analysis of the sca4 gene sequences of SFG Rickettsia showed that all positive samples had 97.60-98.72% identity with tick isolates from Ukraine. In addition, the phylogenetic analysis showed that all the SFG Rickettsia ompA and sca4 sequences obtained from this study belong to the same clade as Rickettsia raoultii isolated from livestock and ticks from China and other countries. Molecularly, this study detected and characterized SFG Rickettsia both in the tick vectors and animals, suggesting that the relationship between SFG Rickettsia, tick species and animal hosts should be explored to understand their interrelationships, which provide a theoretical basis for preventing control of this pathogen.