Search

Current therapies for hepatitis B virus (HBV) infection can slow disease progression but cannot cure the infection, as it is difficult to eliminate or permanently silence HBV covalently closed circular DNA (cccDNA). The interaction between host factors and cccDNA is essential for their formation, stability, and transcriptional activity. Here, we focused on the regulatory role of the host factor ENPP1 and its interacting transcription factor LMNB1 in HBV replication and transcription to better understand the network of host factors that regulate HBV, which may facilitate the development of new antiviral drugs. Overexpression of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) in Huh7 cells decreased HBV pregenomic RNA (pgRNA) and hepatitis B core antigen (HBcAg) expression levels, whereas knockdown of ENPP1 increased them. A series of HBV promoter and mutant plasmids were constructed, and a luciferase reporter assay showed that overexpression of ENPP1 caused inhibition of the HBV promoter and its mutants. A DNA pull-down assay showed that lamin B1 (LMNB1), but not ENPP1, interacts directly with the HBV enhancer II/ basic core promoter (EnhII/BCP). ZDOCK and PyMOL software were used to predict the interaction of ENPP1 with LMNB1. Overexpression of LMNB1 inhibited the activity of the HBV promoter and its mutant. The acetylation levels at the amino acids 111K, 261K, and 483K of LMNB1 were reduced compared to the control, and an LMNB1 acetylation mutant containing 111R, 261Q, 261R, 483Q, and 483R showed increased promoter activity. In summary, ENPP1 together with LMNB1 increased the acetylation level at 111K and 261K, and LMNB1 inhibited the activity of HBV promoter and downregulated the expression of pregenomic RNA and HBcAg. Our follow-up studies will investigate the expression, clinical significance, and relevance of ENPP1 and LMNB1 in HBV patient tissues, explore the effect of LMNB1 on post-transcriptional progression, and examine whether ENPP1 can reduce cccDNA levels in the nucleus. [ABSTRACT FROM AUTHOR]

It is still desirable to obtain the catalysts to degrade organic dye pollutants at room temperature, which meets the current demands of pollutant-removing and energy-saving simultaneously. By a facile precipitation method, we prepared in this work a new, highly efficient CeHIO 6 ·4H 2 O catalyst. By characterization, it was found that the CeHIO 6 ·4H 2 O sample is in nature a yellow inorganic semiconductor with particle size of 0.2–10 μm, band gap of 2.75 eV, low surface area of 1.52 m 2  g −1 and amorphous structure. The CeHIO 6 ·4H 2 O catalyst showed high activity in degradation of rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) in the dark at room temperature. After being used for 3 cycles, it did not undergo significant loss of activity and kept its chemical composition unchanged in the degradation experiments. More importantly, its activity is remarkably higher than that of the previously reported Ce(IO 3 ) 4 , CeGeO 4 , ZrHIO 6 ·4H 2 O and Ce-doped MoO 3 analogues. The major active species and the catalytic mechanism for the dye degradation were proposed. [ABSTRACT FROM AUTHOR]

Developing efficient catalysts capable of degrading organic dye free of light irradiation is highly interesting from the energy-saving point of view. In this work, we prepared a new Ce(IO 3 ) 4 catalyst by a facile precipitation method. The obtained Ce(IO 3 ) 4 sample showed remarkably superior performance to the reported CeGeO 4 analog in degradation of rhodamine B (RhB), methyl orange (MO) or methylene blue (MB) dyes in the dark at room temperature. The ultraviolet-visible (UV–vis) absorption spectra of dye solution during degradation, the XPS results of Ce(IO 3 ) 4 and the control experiments confirmed that the dye degradation is a catalytic process. The reusability of it was also investigated in the degradation experiments. [ABSTRACT FROM AUTHOR]

Host‐associated microbiota can significantly impact host fitness. Therefore, naturally occurring variations in microbiota may influence the health and persistence of their hosts. This finding is particularly important in reintroduced animals, as they typically experience habitat changes during translocations. However, little is known about how microbiomes are altered in response to conservation translocation. Here, we accessed the gut microbiome of Przewalski's horse (Equus przewalskii) populations in China from three nature reserves (i.e. Xinjiang Kalamaili Nature Reserve, KNR; Dunhuang Xihu National Nature Reserve, DXNNR; and Anxi Extreme‐arid Desert Nature Reserve, AENR) using 16s rRNA gene and metagenome sequencing. The results showed that the microbial composition and function differed significantly across locations, while a subset of core taxa was consistently present in most of the samples. The abundance of genes encoding microbe‐produced enzymes involved in the metabolism of carbohydrates, especially for glycoside hydrolases, was significantly higher in open‐spaced KNR populations than in more confined AENR individuals. This study offers detailed and significant differential characters related to the microbial community and metabolic pathways in various reintroduced sites of Przewalski's horse, which might provide a basis for future microecological and conservation research on endangered reintroduced animals. [ABSTRACT FROM AUTHOR]

Based on daily mean temperature data from 32 meteorological stations in the Qinling Mountains (QMs) of China, we analyzed the characteristics and differences of the spatiotemporal changes in the climatic growing season (CGS) in the QMs from 1964 to 2015. Our results are as follows. First, over the past 52 years, the temperature of the QMs significantly increased at a mean rate of 0.22 °C/decade (P < 0.01) in over 98.04% of the area. Significant north–south spatial differences were observed in temperature changes; also, significant differences in the temperature changing trends were observed before and after the abrupt change in temperature. Second, the spatial distributions of the mean growing season start (GSS), end (GSE), and length (GSL) in the QMs varied based on regional differences in latitude and topography. Notably, the GSS, GSE, and GSL were gradually delayed, advanced, and shortened, respectively, as latitude and elevation increased. After the abrupt change in temperature, whether it is in the NSQM (northern slopes of the QMs) or the SSQM (southern slopes of the QMs), the GSS, GSE, and GSL expanded into high-elevation areas. Third, over the past 52 years, the GSS in the QMs exhibited a significant advancing trend of 2.7 days/decade, the GSE was delayed at a rate of 0.66 days/decade, and the GSL displayed a significant extension of 3.36 days/decade. Before the abrupt change in temperature, the GSS, GSE, and GSL exhibited non-significant changing trends; however, the trends in the GSS, GSE, and GSL were more significant after the abrupt change than before. Fourth, the GSS, GSE, and GSL trends in the QMs were significantly different in the NSQM and SSQM regions. After the abrupt change, the GSS, GSE, and GSL trends along the NSQM were more significant than those along the SSQM. [ABSTRACT FROM AUTHOR]

It is of great significance to study on the shift of temperature zone boundaries for revealing the climate change pattern and its environmental effects. Based on daily average temperature data from 32 standard meteorological stations in the Qinling Mountains from 1964 to 2015, the growing season start and end (GSS and GSE) of the climatic growing season parameters were calculated based on a temperature threshold of 10 °C, and the growing season length (GSL) was obtained by subtracting GSE from GSS. We have analyzed the spatiotemporal variations of these parameters in the Qinling Mountains and the shift rules of the warm temperate zone and northern subtropics zone boundaries in China over the past 52 years. Our research generated three primary results. First, the spatial distribution and changing trends of the GSS, GSE, and GSL were significantly different before and after abrupt changes in temperature. After the abrupt change, the coverages of the three were all gradually expanding to the higher altitude areas. The change rates of the three were faster, the trends were more significant, and the differences between the north and the south were obvious, especially in the northern slope. Second, the boundaries of both the warm temperate zone and the northern subtropical zone in China showed upward position shifts, and the area coverage changed along the northern and southern slopes of the Qinling Mountains, and the change amplitudes were even greater after the abrupt change in temperature. Third, there was a significant north–south difference in the response of China's temperature zones to climate change. The temperature zone on the northern slope was more sensitive to climate warming. It is worth emphasizing that the shifts of the temperature zones did not change the fact that the Qinling Mountains are the boundary between China's subtropical and the warm temperate zones. The north subtropical zone is still located on the southern slope of the Qinling Mountains, and the northern slope is still in the warm temperate zone. [ABSTRACT FROM AUTHOR]

The level of CHB virus (HBV) core antibody (HBcAb) is different in four stages of chronic HBV infection and may be used for differential diagnosis of the natural history of chronic HBV infection. To address this question, we examined multiple blood biomarkers and assessed the efficacy to diagnose different stages of chronic HBV infection. The quantitative detection of HBcAb, hepatitis B surface antigen (HBsAg), HBV DNA, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and platelet count (PLT) were determined in the serum of 73 cases of low-replicative phase (LR), 46 cases of immune-tolerant phase (IT), 44 cases of immune clearance phase (IC), and 57 cases of HBeAg-negative hepatitis (ENH). Differentiating performance of these serum protein levels was analyzed by receiver operating characteristic (ROC) curve analysis. Our results showed that the levels of HBcAb, ALT, and AST levels were significantly higher in IC and ENH than those in LR and IT (both P ≤ 0.001). The levels of HBV DNA and HBsAg were higher in IC and IT than those in LR and ENH (both P ≤ 0.001). Logistic regression models showed that HBcAb, HBsAg, HBV DNA, ALT, and AST were the independent variables, respectively, and when combined, they provided high diagnostic accuracy for the staging of CHB. To sum up, HBcAb quantification is a new index, which can reflect whether the liver is in the immune activation state of HBV infection, and is related to the inflammatory state of the host liver. The combined detection of HBcAb quantification and other indicators has showed promising efficiency for staging of IC and ENH and can assist the diagnosis and treatment of CHB. [ABSTRACT FROM AUTHOR]

This paper has made proposition of a nested array and an estimation algorithm for direction-of-arrival (DOA) of two-dimensional (2D) coherently distributed (CD) sources. According to the difference coarray concept, double parallel hole-free virtual uniform linear arrays are generated by virtue of vectorization operation on cross-correlation matrices of subarrays. Sensor coordinates of virtual arrays are derived. Rational invariance relationships of virtual arrays are derived. According to the rotational invariance relationships, matrices satisfying rotation invariance are constructed by extracting and regrouping the receive vectors of the virtual arrays, and then an estimation of signal parameters via rotational invariance techniques- (ESPRIT-) like framework on matrix reconstruction is deduced. Optimal configuration of the nested array as well as computational complexity are analyzed. Without pair matching, the proposed method can resolve more sources than the sensor number. Simulation outcomes indicate that the proposed method tends to have a better performance as compared to the traditional uniform arrays that have similar number of sensors. [ABSTRACT FROM AUTHOR]

Based on daily mean temperature data from 32 meteorological stations in the study area, this paper discusses the relationship between the changes in the climatic growing season and altitude and the differences in the northern (NSQM) and southern (SSQM) slopes of the Qinling Mountains (QMs) from 1985 to 2015. Our analyses generated three primary results. First, the spatial distribution patterns of the growing season start (GSS), growing season end (GSE), and growing season length (GSL) exhibited an altitudinal gradient and differences between the NSQM and SSQM. The occurrence time of the GSS, GSE, and the GSL of the NSQM was approximately 15 days later, 10 days earlier, and 25 days shorter respectively than that of the SSQM. Second, the three factors exhibited regular changes with an increasing elevation gradient: the GSS, GSE, and GSL were gradually delayed, advanced, and shortened, respectively. In the area below 1800 m above sea level, the GSS, GSE, and GSL of the NSQM was later, earlier, and shorter, respectively, than that of the SSQM; while the changing trends in the three were opposite in the areas above 2700 m; and the three in the areas between 1800 and 2700 m varied little in the NSQM and SSQM. The sensitivities of the GSS, GSE, and GSL of the NSQM and SSQM to elevation also reflected in the trends of inter-annual variability. Third, among the different altitudinal vegetation belts from low-altitude to high-altitude areas, the occurrence time of the GSS and GSE and the duration of the GSL in the alpine meadow areas were all exchanged in the NSQM and SSQM. The GSS, GSE, and GSL of the NSQM were earlier, later, and longer respectively than that of the SSQM. [ABSTRACT FROM AUTHOR]

Graphical abstract An economic and green "couplet medicine" strategy was proposed for the first time for preventing Chinese medicinal materials from toxigenic fungi and aflatoxins contamination. Highlights • Toxigenic fungi and aflatoxins contamination affect the quality and safety of Chinese Medicinal Materials. • An economic and environment-friendly "couplet medicine" strategy prevents Chinese Medicinal Materials from the contamination. • The green strategy with low cost and little labor is preferred for scientific preservation of Chinese Medicinal Materials. • Embedding and stacking methods for practical operation to prevent Chinese Medicinal Materials away from toxigenic fungi. Abstract An economic, safe and environment-friendly strategy for preventing Chinese medicinal materials from fungi and aflatoxins contamination is in great need. This study aimed to develop a "couplet medicine" technique with low cost, little time and few labors for the first time for scientific preservation of Radix Notoginseng by investigating the inhibitory efficacy of some aromatic Chinese medicinal materials regarding their anti- Aspergillus flavus properties with the mold changes and aflatoxins accumulation as the detection indexes. An ultra-performance liquid chromatography with fluorescence detection method was validated for sensitive determination of four aflatoxins in Radix Notoginseng without or with the effects of protector from the couplet medicines. It was found that Cortex Cinnamomi , Fructus Anisi Stellati , Flos Caryophylli and Cortex Moutan with strong anti- A. flavus activities could be the potential protector medicines to prevent Radix Notoginseng from molds and aflatoxins contamination. After co-storage of one of the four candidates with Radix Notoginseng to form "couplet medicine", expected results expressed that Cortex Moutan was the best protector medicine at the weight ratio of protector (Cortex Moutan): protégé (Radix Notoginseng) of at least 2:1 (w/w). In practice, the "couplet medicine" of Cortex Moutan - Radix Notoginseng designed through the embedding and stratified stacking modes could effectively prevent toxigenic fungi contamination and aflatoxins residue in Radix Notoginseng to warrant the quality and safety of this highly-valuable Chinese medicinal material. The green "couplet medicine" strategy with lower cost and less labor can be preferred for scientific preservation of Chinese medicinal materials, foods and other matrices. [ABSTRACT FROM AUTHOR]

Fighting against multidrug-resistant bacteria requires reliable methods to evaluate the effect of antibacterial agents. As a universal, non-destructive, and highly sensitive tool, microcalorimetry has been used in many biological investigations to provide continuous real-time monitoring of the metabolic activity. This method, based on heat-flow output, was used to evaluate the influence of two flavonoid compounds (liquiritigenin and liquiritin) on Escherichia coli. Some crucial information, such as the thermogenic power-time curve and thermokinetic parameters of E. coli growth affected by the two compounds, was obtained and further studied by chemometric techniques including similarity analysis, multivariate analysis of variance, and principal component analysis. By comparing the values of two main parameters, k (growth rate constant of the second exponential phase) and Q (heat output of the first exponential growth phase) of E. coli based on the box and whisker plot, liquiritigenin and liquiritin could be differentiated according to their antibacterial effects; liquiritin with IC (half-inhibitory concentration) of 198.6 μg mL expressed a stronger antibacterial effect than liquiritigenin with IC of 337.8 μg mL. The glucoside group in liquiritin containing four additional free hydroxyls in the diphenylpropane skeleton was crucial for inducing the antibacterial effect. Liquiritin might be a promising candidate against E. coli. This study provides a valuable method for searching for novel antibacterial agents using microcalorimetry with chemometrics. [ABSTRACT FROM AUTHOR]

As an important part of terrestrial ecosystem and the most sensitive to environmental changes, mountainous areas are rich in biodiversity and high value of ecosystem productivity. However, due to the unsustainable exploitation of natural resources, most of the world's mountain ecosystems are being subjected to soil erosion and biodiversity is rapidly being lost, so the establishment of mountain ecological reserves is of great importance. In view of this, this paper used the Qinling-Daba Mountain, Qinling Mountain and Daba Mountain of China as the research area. On the basis of various simulated ecosystem service from 2000 to 2015, the root mean square deviation analysis and ordered weighted averaged model were used to determine the spatial changes of ecosystem service on environmental gradients, the tradeoff between ecosystem services and the selection of optimal protection areas. Our results proved that ① net primary production, soil conservation and habitat quality were increase significantly with increasing altitude and vegetation cover fraction gradient, but were weaken water yield and grain production. ② The change in the trade-off between multiple pairs of ecosystem services in the Daba Mountain was stronger than in the Qinling-Daba Mountain and the Qinling Mountain, especially the trade-off relationship related to water yield. ③ Considering various scenarios and conservation efficiency, it was found that scenario 7 was the best solution. The net primary production, soil conservation, habitat quality, grain production, and water yield protection efficiency were 1.261, 4.845, 1.059, 1.333, and 1.390 respectively. Priority conservation areas were mainly distributed in mid-altitude, high-vegetation, and high-mean annual precipitation areas. In this study, the combination of ecosystem services and priority conservation areas can play an important role in the management of the Qinling-Daba Mountain, and provides a meaningful reference for the selection of nature reserves. • Mountain ecosystem services have large spatial heterogeneity on different environmental gradients. • The priority protection area was selected by comparing the protection efficiency of different areas. • Explore the mechanism analysis and the trade-off relationship between mountain ecosystem services. • The combination of ecosystem services and protected areas can provide reference for mountain ecological planning. [ABSTRACT FROM AUTHOR]

A direction of arrival (DOA) estimator for two-dimensional (2D) incoherently distributed (ID) sources is presented under proposed double cross arrays, satisfying both the small interval of parallel linear arrays and the aperture equalization in the elevation and azimuth dimensions. First, by virtue of a first-order Taylor expansion for array manifold vectors of parallel linear arrays, the received signal of arrays can be reconstructed by the products of generalized manifold matrices and extended signal vectors. Then, the rotating invariant relations concerning the nominal elevation and azimuth are derived. According to the rotating invariant relationships, the rotating operators are obtained through the subspace of the covariance matrix of the received vectors. Last, the angle matching approach and angular spreads are explored based on the Capon principle. The proposed method for estimating the DOA of 2D ID sources does not require a spectral search and prior knowledge of the angular power density function. The proposed DOA estimation has a significant advantage in terms of computational cost. Investigating the influence of experimental conditions and angular spreads on estimation, numerical simulations are carried out to validate the effectiveness of the proposed method. The experimental results show that the algorithm proposed in this paper has advantages in terms of estimation accuracy, with a similar number of sensors and the same experimental conditions when compared with existing methods, and that it shows a robustness in cases of model mismatch. [ABSTRACT FROM AUTHOR]

Background: Gasterophilus species are widely distributed around the world. The larvae of these flies parasitize the digestive tract of equids and cause damage, hindering horse breeding and protection of endangered species. However, study of the genetic structure of geographically distinct Gasterophilus populations is lacking. Here, we analyzed the genetic diversity of Gasterophilus pecorum, G. intestinalis, G. nasalis and G. nigricornis from three typical grasslands (meadow, desert and alpine steppes) in China as compared to published sequences from Italy, Poland and China (Daqing and Yili), based on the mitochondrial cytochrome c oxidase cox1 and cox2 gene sequences. Results: Haplotype diversity and nucleotide diversity of mitochondrial genes was generally high in all Gasterophilus populations. Due to the unique natural climatic conditions of the alpine steppe, there were high levels of genetic differentiation among different geographical populations of G. pecorum and G. nasalis, indicating that environmental variations influenced population genetic structure. Frequent exchanges between meadow and desert steppe Gasterophilus species resulted in low genetic differentiation. The highest exchange rates were found among G. intestinalis populations. Genetic differentiation was only observed on a large geographical scale, which was confirmed by analyzing population genetic structure. Three species, G. pecorum, G. intestinalis and G. nasalis, from meadow steppe showed a high emigration rate, indicating that the direction of Gasterophilus dispersal in China was from east to west. Conclusions: Our results show that the four Gasterophilus species have a high level of genetic diversity and different degrees of genetic differentiation and gene flow among different populations of the same species, reflecting their potential to adapt to the environment and the environmental impact on genetic structure. Knowledge of the genetic structure, population history, and migration will help understand the occurrence and prevalence of gasterophilosis and provide a basis for controlling the local spread of Gasterophilus spp. [ABSTRACT FROM AUTHOR]