Search

Abstract We recently detected a HKU4-related coronavirus in subgenus Merbecovirus (named pangolin-CoV-HKU4-P251T) from a Malayan pangolin1. Here we report isolation and characterization of pangolin-CoV-HKU4-P251T, the genome sequence of which is closest to that of a coronavirus from the greater bamboo bat (Tylonycteris robustula) in Yunnan Province, China, with a 94.3% nucleotide identity. Pangolin-CoV-HKU4-P251T is able to infect human cell lines, and replicates more efficiently in cells that express human-dipeptidyl-peptidase-4 (hDPP4)-expressing and pangolin-DPP4-expressing cells than in bat-DPP4-expressing cells. After intranasal inoculation with pangolin-CoV-HKU4-P251, hDPP4-transgenic female mice are likely infected, showing persistent viral RNA copy numbers in the lungs. Progressive interstitial pneumonia developed in the infected mice, characterized by the accumulation of macrophages, and increase of antiviral cytokines, proinflammatory cytokines, and chemokines in lung tissues. These findings suggest that the pangolin-borne HKU4-related coronavirus has a potential for emerging as a human pathogen by using hDPP4.

BACKGROUND Polycyclic aromatic hydrocarbons (PAHs), as a typical persistent organic pollutant, widely exist in the environment and have high stability. Studying of the content distribution and source analysis of PAHs in soil will provide a technical basis for PAHs pollution prevention and control, ecological environment improvement and environmental protection policy-making. OBJECTIVES In order to investigate the content, composition and source of PAHs in the soil environment of different functional areas in Beijing City. METHODS A large-scale sampling was carried out in the core area of Beijing City. At the same time, regional sampling was carried out for different functional areas such as industrial areas, agricultural planting areas, water source protection areas and residential areas. A total of 459 topsoil samples were collected, and the monomer contents of 16 PAHs were analyzed by gas chromatography-mass spectrometry (GC-MS). RESULTS The average values of the total contents of 16 PAHs (∑16PAHs) in topsoil of the three subregions in the core area (southeast, center and northwest) were 153.7, 333.2 and 142.9μg/kg, respectively. The average values of ∑16PAHs in topsoil of the industrial zone, including Southeast Factory, Shougang Industry and Datai Coal Mine, were 1006.9, 1379.4 and 146.8μg/kg, respectively. The average values of ∑16PAHs in topsoil of the water-conserving areas, Huairou and Miyun, were 86.4μg/kg and 154.5μg/kg, respectively. The average values of ∑16PAHs in topsoil of four agricultural planting regions (Changping, Pinggu, Fangshan and Tongzhou) were 109.0, 118.3, 106.8 and 94.2μg/kg, respectively. The average value of ∑16PAHs in topsoil of residential areas was 131.1μg/kg. Compared with previous research results on the content and distribution characteristics of PAHs, the content of PAHs in the topsoil in Beijing City showed a decreased trend, which was related to the decrease in the use of coal and the increase in the use of natural gas in Beijing City in recent years. The composition of PAHs in different functional areas was different. The proportion of heavy and medium rings PAHs were higher in industrial areas. The proportion of light rings PAHs in water-conserving areas, agricultural planting regions and residential areas was higher than that in industrial areas, which might be due to the different sources of PAHs in different functional areas. The results of principal component analysis-multiple linear regression method showed that the main sources of PAHs in the core area were tail gas emissions and leakage during oil storage and transportation, which contributed 81.46% and 18.54%, respectively. The main sources of PAHs in the topsoil of the industrial area were coal combustion and tail gas emissions, which contributed 62.65% and 37.35%, respectively. The main sources of PAHs in residential areas were tail gas emissions and natural gas combustion sources, with contribution rates of 53.30% and 46.70%, respectively. CONCLUSIONS Further strengthening traffic control, continuing to reduce the proportion of coal in energy structure, and increasing the proportion of clean energy are effective ways to reduce PAHs emissions and pollution in Beijing City.

Abstract Messenger RNA (mRNA) vaccine technology has shown its power in preventing the ongoing COVID-19 pandemic. Two mRNA vaccines targeting the full-length S protein of SARS-CoV-2 have been authorized for emergency use. Recently, we have developed a lipid nanoparticle-encapsulated mRNA (mRNA-LNP) encoding the receptor-binding domain (RBD) of SARS-CoV-2 (termed ARCoV), which confers complete protection in mouse model. Herein, we further characterized the protection efficacy of ARCoV in nonhuman primates and the long-term stability under normal refrigerator temperature. Intramuscular immunization of two doses of ARCoV elicited robust neutralizing antibodies as well as cellular response against SARS-CoV-2 in cynomolgus macaques. More importantly, ARCoV vaccination in macaques significantly protected animals from acute lung lesions caused by SARS-CoV-2, and viral replication in lungs and secretion in nasal swabs were completely cleared in all animals immunized with low or high doses of ARCoV. No evidence of antibody-dependent enhancement of infection was observed throughout the study. Finally, extensive stability assays showed that ARCoV can be stored at 2–8 °C for at least 6 months without decrease of immunogenicity. All these promising results strongly support the ongoing clinical trial.

Blastocystis is a protozoan that parasitizes the intestines. A number of hosts of Blastocystis have been found, including human and animals. However, there has been no research on the prevalence of Blastocystis in Tibetan antelope. Here, a molecular test was performed using 627 Tibetan antelope fecal samples collected on Tibet in China from 2019 to 2020. The result showed that 30 (4.8%) samples were Blastocystis positive. The highest prevalence of Blastocystis was in Shuanghu County (25/209, 12.0%), followed by Shenza County (2/103, 1.9%), Nyima County (3/182, 1.6%), and Baigoin County (0/133, 0.0%). In addition, logistic regression analysis showed that the gender, sampling year, and area of Tibetan antelope were risk factors for Blastocystis prevalence. Three subtypes (ST10, ST13, and ST14) of Blastocystis were found in Tibetan antelope through a subtype sequence analysis, and ST13 was identified to be the dominant subtype. This is the first investigation for the infection of Blastocystis in Tibetan antelope. Collectively, the data in this study have expanded the host range of Blastocystis and provided basic information for the distribution of Blastocystis subtypes, which could support the prevention of Blastocystis infection in wild animals.

Migratory birds play an important role in the spread of multidrug-resistant (MDR) bacteria. To investigate the prevalence of MDR Escherichia coli in migratory birds in China and potential relationships with the environment, a total of 1387 samples (fecal samples, cloacal swabs, or throat swabs) were collected from migratory birds from three different river basins in China. The collected samples were processed and subjected to bacteriological examinations. Antimicrobial susceptibility testing of the recovered isolates was performed using the E-test for the detection of minimum inhibitory concentrations (MICs). Some antibiotic resistance genes were detected and the PCR products were confirmed by sequencing. In total, 478 (34.7%) E. coli isolates were recovered. The results showed that the drug-resistant E. coli isolates were highly resistant to β-lactams (43.7%) and tetracycline (22.6%), and 73 (15.3%) were MDR, including eight that were extended spectrum β-lactamase-positive. The retrieved strains harbored the blaCTX-M, blaTEM-1, tet(A), tet(B), tet(M), sul1, sul2, sul3, cmlA, floR, and intI1 genes with a prevalence of 5.9%, 36.4%, 80.5%, 11.9%, 6.8%, 6.8%, 47.5%, 12.7%, 50.8%, 37.3%, and 61.0%, respectively. The drug resistance rate of the isolates from southern China was higher than those from northern China. The E. coli samples collected for migratory birds in the Pearl River Basin had the highest proportion (46.7%) MDR isolates. Furthermore, MDR bacteria carried by migratory birds were closely related to the antibiotic content in the basin, which confirms that MDR bacteria carried by migratory birds are likely acquired from the environment. This study also confirmed that migratory birds are potential transmitters of MDR bacteria, demonstrating the need to reduce the use and emission of antibiotics and further in-depth studies on the mechanisms underlying drug resistance of bacteria.

The pressure–temperature (P‐T) path of blueschist is usually applied to understanding the evolution of the subducted oceanic crust. Garnet plays a key role in calculating the metamorphic conditions, but sometimes it is absent in the blueschists. Nevertheless, the high‐P experimental simulation may serve as a useful tool to constrain the P‐T conditions. In the middle of the Longmu Co‐Shuanghu Suture, North Tibet, blueschist blocks embedded in the marble were discovered, where garnet is abundant in the core but absent in the marble‐contacting margin. These two kinds of blueschist contain similar mineral assemblage (glaucophane, epidote, and phengite) and show comparable basaltic character. Pseudosection modelling was applied to the garnet‐bearing blueschist that calculated the peak metamorphic condition of ca. 1.9 GPa and 530°C. As for the garnet‐absent blueschist, experiments (1.2–2.3 GPa and 500–800°C) were performed on the designed mixture of 93 wt% basalt and 7 wt% calcite. The results show that the total Fe content in the glaucophane and barroisite is positively correlated with the pressure but not with temperature, which could be regarded as a geobarometer. Accordingly, the peak condition was constrained at 2.3 GPa and 500–600°C. Therefore, the equivalent metamorphic conditions of the blueschists indicate that the Palaeo‐Tethys oceanic crust subducted into at least 70 km. Furthermore, both the experiments and the T‐X (CaCO3) pseudosection, constructed based on basaltic lithology, support that the absence of garnet in the blueschist is predominantly caused by the mixing of calcite. In summary, this study provides a valid attempt in exploring metamorphic conditions by experiment simulation, and evaluates the profound influence of the interaction between the basaltic crust and overlying carbonate‐bearing sediments in the subduction zone. [ABSTRACT FROM AUTHOR]

The magmatic suites in the southern margin of South Qiangtang Terrane (SQT) provide important clues to the process of northward subduction of the Banggong‐Nujiang Tethys Ocean (BNTO) and its geodynamic evolution. Previous studies identified a magmatic gap from Late Jurassic to Early Cretaceous (ca. 150–130 Ma) in the southern margin of SQT. Although the gap is generally correlated with the process related to BNTO subduction, the previous models on this remain equivocal. In this study, we investigated a suite of bimodal magmatic rocks newly recognized in the Rigenco area of SQT, including gabbros and granodiorites which were dated at 151.7 ± 3.8 Ma and 150.0 ± 2.0 Ma respectively. Based on geochemical and isotopic analyses, it is inferred that the gabbroic magmas were derived from a sub‐arc mantle source enriched by metasomatism of voluminous slab‐derived and crustal compositions, and that the granodiorites were derived from sub‐arc juvenile lower crust. Combining the petrogenesis of gabbros and granodiorites, it is proposed that the bimodal magmas were produced under a tectonic setting of general compression with local extension. A detailed evaluation of the tectonic setting of the magmatic bimodal suite suggests crustal thickening at ca. 150 Ma and that the BNTO involved multiple arcs and sub‐basins. A new model of arc‐SQT collision is proposed to account for the magmatic gap which commenced at ca. 150 Ma. The model of arc–continent collision in this case can well explain the present distribution and occurrence of magmatic rocks of late Jurassic age in the southern margin of the SQT, especially the magmatic gap. Our discovery of Late Jurassic bimodal rocks provides a critical evidence for step‐wise arc–continent collision during BNTO subduction, and contributes to the understanding of the magmatic gap in SQT and the evolution of BNTO. [ABSTRACT FROM AUTHOR]

Serpentinised ultramafic rocks are widely distributed in the Bangong–Nujiang suture zone (BNSZ) and show close relationship with the regional mineralisation. Here, we investigate the serpentinised ultramafic rocks from Angwu in the central segment of the BNSZ, where the primary minerals include olivine, clinopyroxene, chromite, lizardite, magnetite, and chlorite. Based on a comprehensive analysis of the results from petrography, back‐scattered electron images (BSE), and energy dispersive spectrographs (EDS), as well as electron probe microanalysis (EPMA), the alteration process of the ultramafic rocks, including serpentinisation, can be divided into three stages: 1, formation of relatively Fe‐rich serpentine (Mg#, 0.82), with no precipitation of magnetite; 2, formation of relatively Mg‐rich serpentine (Mg#, 0.93), with precipitation of magnetite in serpentine veins; and 3, alteration of serpentine into chlorite. We computed the reactions associated with alteration process for the above stages. In addition, thermodynamic modelling in multicomponent mineral equilibrium phase diagrams indicate that during the serpentinisation process, the desilication of pyroxene in caused the enhancement of SiO2 activity and restricted the transformation from olivine to magnetite. The reaction temperature for the serpentinisation of these rocks was relatively high, and within this temperature interval (100–300°C), lizardite was stable, and precipitation of magnetite was not favoured. We also evaluate the factors influencing magnetite precipitation during serpentinisation of ultramafic rocks including the composition of primitive rocks and the activity of SiO2 and temperature. Our study provides insights on the mechanism of magnetite mineralisation associated with the serpentinisation of ultramafic rocks. [ABSTRACT FROM AUTHOR]