TIM22 and TIM29 inhibit HBV replication by up-regulating SRSF1 expression.

Hepatitis B virus (HBV) infection is a serious global health problem. After the viruses infect the human body, the host can respond to the virus infection by coordinating various cellular responses, in which mitochondria play an important role. Evidence has shown that mitochondrial proteins are involved in host antiviral responses. In this study, we found that the overexpression of TIM22 and TIM29, the members of the inner membrane translocase TIM22 complex, significantly reduced the level of intracellular HBV DNA and RNA and secreted HBV surface antigens and E antigen. The effects of TIM22 and TIM29 on HBV replication and transcription is attributed to the reduction of core promoter activity mediated by the increased expression of SRSF1 which acts as a suppressor of HBV replication. This study provides new evidence for the critical role of mitochondria in the resistance of HBV infection and new targets for the development of treatment against HBV infection.

[A new dihydrostilbene from aerial part of Cannabis sativa].

The present study investigated the chemical constituents in the aerial part of Cannabis sativa. The chemical constituents were isolated and purified by silica gel column chromatography and HPLC and identified according to their spectral data and physicochemical properties. Thirteen compounds were isolated from the acetic ether extract of C. sativa and identified as 3',5',4″,2-tetrahydroxy-4'-methoxy-3-methyl-3″-butenyl p-disubstituted benzene ethane(1), 16R-hydroxyoctadeca-9Z,12Z,14E-trienoic acid methyl ester(2),(1'R,2'R)-2'-(2-hydroxypropan-2-yl)-5'-methyl-4-pentyl-1',2',3',4'-tetrahydro-(1,1'-biphenyl)-2,6-diol(3), ß-sitosteryl-3-O-ß-D-glucopyranosyl-6'-O-palmitate(4), 9S,12S,13S-trihydroxy-10-octadecenoate methyl ester(5), benzyloxy-1-O-ß-D-glucopyranoside(6), phenylethyl-O-ß-D-glucopyranoside(7), 3Z-enol glucoside(8), α-cannabispiranol-4'-O-ß-D-glucopyranose(9), 9S,12S,13S-trihydroxyoctadeca-10E,15Z-dienoic acid(10), uracil(11), o-hydroxybenzoic acid(12), and 2'-O-methyladenosine(13). Compound 1 is a new compound, compound 3 is a new natural product, and compounds 2, 4-8, 10, and 13 were isolated from Cannabis plant for the first time.

Caspase sensors based on NanoLuc.

Caspases are a family of evolutionary conserved cysteine proteases that play key roles in programmed cell death and inflammation. Among the methods for the detection of caspase activity, biosensors based on luciferases have advantages in genetical encoding and convenience in assay. In this study, we constructed a new set of caspase biosensors based on NanoLuc luciferase. This kind of sensors, named NanoLock, work in dark-to-bright model, with the help of a NanoLuc quencher peptide (HiBiT-R/D) mutated from HiBiT. Optimized NanoLock responded to proteases with high signal to noise ratio (S/N), 1233-fold activation by tobacco etch virus protease in HEK293 cells and > 500-fold induction to caspase 3 in vitro. We constructed NanoLocks for the detection of caspase 1, 3, 6, 7, 8, 9, and 10, and assays in HEK293 cells demonstrated that these sensors performed better than commercial kits in the aspect of S/N and convenience. We further established a cell line stably expressing NanoLock-casp 6 and provided a proof-of-concept for the usage of this cell line in the high throughput screening of caspase 6 modulator.

Identification of STAU1 as a regulator of HBV replication by TurboID-based proximity labeling.

The core promoter (CP) of hepatitis B virus (HBV) is critical for HBV replication by controlling the transcription of pregenomic RNA (pgRNA). Host factors regulating the activity of the CP can be identified by different methods. Biotin-based proximity labeling, a powerful method with the capability to capture weak or dynamic interactions, has not yet been used to map proteins interacting with the CP. Here, we established a strategy, based on the newly evolved promiscuous enzyme TurboID, for interrogating host factors regulating the activity of HBV CP. Using this strategy, we identified STAU1 as an important factor involved in the regulation of HBV CP. Mechanistically, STAU1 indirectly binds to CP mediated by TARDBP, and recruits the SAGA transcription coactivator complex to the CP to upregulate its activity. Moreover, STAU1 binds to HBx and enhances the level of HBx by stabilizing it in a ubiquitin-independent manner.

Protein sensors combining both on-and-off model for antibody homogeneous assay.

Protein sensors based on allosteric enzymes responding to target binding with rapid changes in enzymatic activity are potential tools for homogeneous assays. However, a high signal-to-noise ratio (S/N) is difficult to achieve in their construction. A high S/N is critical to discriminate signals from the background, a phenomenon that might largely vary among serum samples from different individuals. Herein, based on the modularized luciferase NanoLuc, we designed a novel biosensor called NanoSwitch. This sensor allows direct detection of antibodies in 1 µl serum in 45 min without washing steps. In the detection of Flag and HA antibodies, NanoSwitches respond to antibodies with S/N ratios of 33-fold and 42-fold, respectively. Further, we constructed a NanoSwitch for detecting SARS-CoV-2-specific antibodies, which showed over 200-fold S/N in serum samples. High S/N was achieved by a new working model, combining the turn-off of the sensor with human serum albumin and turn-on with a specific antibody. Also, we constructed NanoSwitches for detecting antibodies against the core protein of hepatitis C virus (HCV) and gp41 of the human immunodeficiency virus (HIV). Interestingly, these sensors demonstrated a high S/N and good performance in the assays of clinical samples; this was partly attributed to the combination of off-and-on models. In summary, we provide a novel type of protein sensor and a working model that potentially guides new sensor design with better performance.

Expanded analyses of the functional correlations within structural classifications of glycoside hydrolases.

Glycoside hydrolases (GHs) are greatly diverse in sequences and functions, but systematic studies of GH relationships based on structural information are lacking. Here, we report that GHs have multiple evolutionary origins and are structurally derived from 27 homologous superfamilies and 16 folds, but GHs are highly biased to distribute in a few superfamilies and folds. Six of these superfamilies are widely encoded by archaea, bacteria, and eukaryotes, indicating that they may be the most ancient in origin. Most superfamilies vary in enzyme function, and some, such as the superfamilies of (ß/α)8-barrel and (α/α)6-barrel structures, exhibit extreme functional diversity; this is highly positively correlated with sequence diversity. More than one-third of glycosidase activities show a phenomenon of convergent evolution, especially the degradation functions of GHs on polysaccharides. The GHs of most superfamilies have relatively narrow environmental distributions, normally with the highest abundance in host-associated environments and a distribution preference for moderate low-temperature and acidic environments. Overall, our expanded analysis facilitates an understanding of complex GH sequence-structure-function relationships and may guide our screening and engineering of GHs.

[Distribution of soil moisture and salt of Tamarix ramosissima plantation in desert saline-alkali land of Hexi Corridor Region, China]. / æ²³è¥¿èµ°å»Šè’æ¼ ç›ç¢±åœ°äººå·¥æŸ½æŸ³æž—åœŸå£¤æ°´ç›åˆ†å¸ƒ.

Soil salinization is a global problem. Afforestation is a major improvement practice for desert saline-alkali land. To examine ecological improvement effects and spatial distribution of soil moisture and salinity in Tamarix ramosissima plantation with the age of 10 years in desert saline-alkali land, soil moisture and salt content between rows and under shrubs with row distance of 2, 4, 6, and 8 m were measured. The structural equation model was used to quantify the effects of soil water and salt changes on plant growth. The results indicated that soluble salt in shallow soil (0-40 cm) of T. ramosissima plantation was significantly lower than that outside the plantation, but soil moisture under shrubs was higher than that between rows. Among different row distances, the maximum values of height and canopy size of T. ramosissima and coverage and biomass of vegetation under the shrubs were found in row distance of 6 m. The enrichment degree of soil cations around taproot was in order of Na+>K+>Ca2+>Mg2+ and anions were enriched with Cl->HCO3->SO42-. There were five kinds of salts in soil, with MgSO4 being the most abundant, followed by CaCl2, NaCl and MgCl2, and the lowest being KHCO3. Soil moisture had the strongest effects on vegetation, followed by soil salinity, and the lowest was soil pH, with values of 50.6%,29.5% and 19.9%, respectively.

Rational Design of Crystalline Covalent Organic Frameworks for Efficient CO2 Photoreduction with H2 O.

Solar energy-driven conversion of CO2 into fuels with H2 O as a sacrificial agent is a challenging research field in photosynthesis. Herein, a series of crystalline porphyrin-tetrathiafulvalene covalent organic frameworks (COFs) are synthesized and used as photocatalysts for reducing CO2 with H2 O, in the absence of additional photosensitizer, sacrificial agents, and noble metal co-catalysts. The effective photogenerated electrons transfer from tetrathiafulvalene to porphyrin by covalent bonding, resulting in the separated electrons and holes, respectively, for CO2 reduction and H2 O oxidation. By adjusting the band structures of TTCOFs, TTCOF-Zn achieved the highest photocatalytic CO production of 12.33 µmol with circa 100 % selectivity, along with H2 O oxidation to O2 . Furthermore, DFT calculations combined with a crystal structure model confirmed the structure-function relationship. Our work provides a new sight for designing more efficient artificial crystalline photocatalysts.

Bioinformatical analysis of the sequences, structures and functions of fungal polyketide synthase product template domains.

The product template (PT) domains, specifically in fungal non-reducing polyketide synthases (NR-PKSs), mediate the regioselective cyclization of polyketides dominating the final structures. However, up to date, the systematic knowledge about PT domains has been insufficient. In present study, the relationships between sequences, structures and functions of the PT domains were analyzed with 661 NR-PKS sequences. Based on the phylogenetic analysis, the PT domains were classified into prominent eight groups (I-VIII) corresponding with the representative compounds and cyclization regioselectivity (C2-C7, C4-C9, and C6-C11). Most of the cavity lining residue (CLR) sites in all groups were common, while the regional CLR site mutations resulted in the appearance of finger-like regions with different orientation. The cavity volumes and shapes, even the catalytic dyad positions of PT domains in different groups were corresponding with characteristic cyclization regioselectivity and compound sizes. The conservative residues in PT sequences were responsible for the cyclization functions and the evolution of the key residues resulted in the differentiations of cyclization functions. The above findings may help to better understand the cyclization mechanisms of PT domains and even predict the structural types of the aromatic polyketide products.

[Chemical constituents from roots of Ixeris chinensis].

Silica gel column chromatography and preparative HPLC were applied to isolate the chemical constituents from the roots of Ixeris chinensis. Fifteen compounds were isolated and their structures were elucidated by the physicochemical properties and spectral analysis as chinensioide G(1), chinensioide B(2), 10α-hydroxy-guaia-12,6-lactone-3-keton(3), chinensioide C(4), 10α-hydroxy-11ßH-guaia-4(5) -ene-12,6-lactone (5), 3ß, 10α-dihydroxy-11ßH-guaia-11 (13)-ene-12,6-lactone (6), 3ß, 10α-dihydroxy-4ßH, 11ßH-guaia-12,6-lactone(7), 3ß, 10α-dihydroxy-guaia-4 (15), 11 (13) -diene-12, 6-lactone (8), caffeic acid (9), p-hydorxyphenylacetic acid(10), methyl p-hydroxyphenylacetate (11), ethyl p-hydroxyphenylacetate (12), sitosterol (13), daucosterol (14), and ixerin D(15). Compound 1 was new, and 6 and 7 were isolated from I. chinensis for the first time.

[Chemical constituents from Euphorbia lunulata].

The chemical constituents from Euphorbia lunulata was investigated in this paper. Fourteen compounds were isolated and purified by column chromatographies on silica gel and preparative HPLC. Their structures were identified by physiochemical properties and NMR data analysis as lupeol (1), euphol (2), cassipourol(3) , 24-methylenecycloartan-3beta-ol (4), 24-hydroperoxycycloart-25-en-3beta-ol (5), 25-hydroperoxycycloart-23-en-3beta-ol (6), betulin (7), uvaol (8), (23E) -25-methoxycycloart-23-en-3beta-ol (9), (23E) -cycloart-23,25-dien-3beta-ol (10), 24-methylenecycloartan-3beta, 28-diol (11), salicinolide (12), 2alpha, 3beta, 5alpha, 9alpha, 15beta-pentaacetoxy-11,12-epoxy-7beta, 8alpha-diisobutyryloxyjatropha-6 (17) -en-14-one (13) and 3beta, 5alpha, 15beta-triacetoxy-7beta-isobutyryloxy-9alpha-nicotinoyloxyjatropha-6 (17), 11(E)-dien-14-one (14). Among them, compounds 1-11 were isolated from E. lunulata for the first time.

[Study on chemical constituents of the Ixeris chinensis].

OBJECTIVE: To study the chemical constituents of the Ixeris chinensis . METHODS: The constituents were isolated by silica gel column chromatography, HPLC and recrystallization and their structures were elucidated on the basis of spectral analysis. RESULTS: Fifteen compounds were isolated and identified as Methyl-4-hydroxyphenylacetate (1), Daucosterol (2), Sitosterol (3), Luteolin-7-O-beta-D-glucoside (4), 15-hydroxy-2-oxoguaia-1 (10), 3,11 (13)-triene-12,6-lactone (5), Chinensiolide B (6), Chinensiolide E (7), Ixerochinoside (8), Chinensiolide C (9), 10alpha-hydroxy-guaia-4(15)-ene-12,6-lactone (10), 10alpha-hydroxy-guaia-4 (15), 11 (13)-diene-12,6-lactone-3beta-O-beta-D-(6'-p-hydroxyphenylacetyl) glucopyranoside (11), Epiloliolide (12), Apigenin-O-beta-D-glucopyranoside (13), Luteolin (14), Lutein (15). CONCLUSION: Compounds 1,10,11,12 and 15 are isolated from this plant for the first time.

[Study on the chemical constituents from fresh roots of Euphorbia fischeriana].

OBJECTIVE: To study the chemical constituents in ethyl acetate fraction from the Euphorbia fischeriana. METHODS: The compounds were isolated by silica gel column chromatography and HPLC, and their structures were elucidated by means of spectral analyses. RESULTS: Fourteen compounds were identified as 2,4-dihydroxy-6-methoxy-3-methylacetophenone (1), 12-deoxyphorbol-13-hexadecanoate (2), ethylgallate (3), esculetin (4), 2,4-dihydroxy-6-methoxy-acetophenone (5), 12-deoxyphorbol-13-acetate (6), 12-deoxyphorbol-13,20-diacetete (7), jolkinolide B (8), 17-hydroxyjolkinolide B (9), 17-hydroxy-jolkinolide A (10), langduin C (11), 3-methylp-hydroxybenzoic acid (12), methyl gallate (13), 3, 3'-diacetyl-pyridine-4,4'-dimethoxy-2, 2', 6, 6'-tetrahydroxydiphenylmethane (14). CONCLUSION: Compounds 3, 5, 12, 13 are isolated from this plant for the first time.

[Studies on the chemical constituents of Pharbitis purpurea].

OBJECTIVE: To study the chemical constituents of Pharbitis purpurea. METHODS: The constituents were isolated by silica gel column chromatography, HPLC and recrystallization and their structures were elucidated on the basis of spectral analysis. RESULTS: Fourteen compounds were isolated and identified as daucosterol (1), umbelliferone (2), ursolic acid (3), N-p-hydroxy-cis-coumaroyltyramine (4), N-p-hydroxy-trans-coumaroyltyramine (5), N-cis-feruloyltyramine (6), N-trans-feruloyltyramine (7), (3R, 5R, 6S, 7E, 9S)-megastigman-5,6-epoxy-7-ene-3,9-diol (8), (6S,9R)-vomifoliol (9), (+)-syringaresinol (10), isovitexin (11), syringopicroside( 12), uricil (13), (6S,9R)-roseoside (14). CONCLUSION: Compounds 3, 8-2,14 are isolated from the genus for the first time.

Basic helix-loop-helix transcription factor from wild rice (OrbHLH2) improves tolerance to salt- and osmotic stress in Arabidopsis.

Salt stress adversely affects plant growth and development. Some plants reduce the damage of high-salt stress by expressing a series of salt-responsive genes. Studies of the molecular mechanism of the salt-stress response have focused on the characterization of components involved in signal perception and transduction. In the present work, we cloned and characterized a basic helix-loop-helix (bHLH) encoding gene, OrbHLH2, from wild rice (Oryza rufipogon), which encodes a homologue protein of ICE1 in Arabidopsis. OrbHLH2 protein localized in the nucleus. Overexpression of OrbHLH2 in Arabidopsis conferred increased tolerance to salt and osmotic stress, and the stress-responsive genes DREB1A/CBF3, RD29A, COR15A and KIN1 were upregulated in transgenic plants. Abscisic acid (ABA) treatment showed a similar effect on the seed germination or transcriptional expression of stress-responsive genes in both wild type and OrbHLH2-overexpressed plants, which implies that OrbHLH2 does not depend on ABA in responding to salt stress. OrbHLH2 may function as a transcription factor and positively regulate salt-stress signals independent of ABA in Arabidopsis, which provides some useful data for improving salt tolerance in crops.

Sesquiterpene lactones from Ixeris sonchifolia (Bge.) Hance II.

Four new sesquiterpene lactones, sonchifoliasolides D (1), E (2), F (3) and G (4) were isolated from the aerial parts of Ixeris sonchifolia (Bge.) Hance. The structures of compounds 1-4 were established on the basis of their spectroscopic data.

[Studies on chemical constituents of Astragalus dahuricus].

OBJECTIVE: To study the chemical constituents in Astragalus dahuricus. METHOD: The compounds were isolated and purified by column chromatography on silica gel and HPLC, and their structures were elucidated by their spectroscopic evidences. RESULT: Six compounds were identified as: 7, 2'-dihydroxy-3', 4'-dimethoxyisoflavan (1), 2'-hydroxy-3', 4'-dimethoxyisoflavan-7-O-beta-D-glucopyranoside (2), 8, 2'-dihydroxy-7, 4'-dimethoxyisoflavan (3), 7-hydroxy-4'-methoxyisoflavone (4), 7, 3'-dihydroxy-4'-metho-xyisoflavone (5), 9, 10-dimethoxypterocarpan-3-O-beta-D-glucopyranoside (6). CONCLUSION: Compounds 1-6 were obtained from this plant for the first time.

[Puerperal practice pattern in a rural area of north China].

OBJECTIVE: To describe women's behavioral patterns in the period of "doing the month" (confinement in childbirth) and to determine the degree of differences between "doing the month" practices and daily behaviors. METHODS: A retrospective survey was conducted with a random sample of 1,813 women who were interviewed using a questionnaire undertaken in May of 2004. RESULTS: The results showed that the majority of women adhered to the traditional customs. While "doing the month", more than 90% of women did not eat cold, hard, or sour food; more than 90% of the women did not wash their hair or body at all, and more than 70% of women did not brush their teeth or wash their feet. As compared to what women normally do, most women drastically changed their practices in eating, sanitation, dress, activity, doing chores, and so on, during their "doing the month". Further analysis indicated that women's age had no effect on the change of practice patterns and that women's education had an inconsequential effect. CONCLUSION: The traditional "doing the month" practices are still very popular in the rural areas of China. Birth belief, illness concept and traditional village culture are the main factors for the pattern of "doing the month".