Identifying ligands directly interacting with target protein in medicinal herbs by metabolomic analysis of T2-filtered HSQC spectra.

A protocol for efficiently identifying ligands directly interacting with a target protein in complex extracts of medicinal herbs was proposed by combining an adapted 2D perfect-echo Carr-Purcell-Meiboom-Gill heteronuclear single quantum correlation (PE-CPMG HSQC) spectrum with metabolomic analysis. PE-CPMG HSQC can suppress the signal interference from the target protein, allowing more accurate peak quantification than conventional HSQC. Inspired from untargeted metabolomics, regions of interest (ROIs) are constructed and quantified for the mixture or complex extract samples with and without a target protein, and then a binding index (BI) of each ROI is determined. ROIs or corresponding peaks significantly perturbed by the presence of the target protein (BI ≥1.5) are detected as differential features, and potential binding ligands identified from the differential features can be equated with bioactive markers associated with the 'treatment' of the target protein. Quantifying ROI can inclusively report the ligand bindings to a target protein in fast, intermediate and slow exchange regimes on nuclear magnetic resonance (NMR) time scale. The approach was successfully implemented and identified Angoroside C, Cinnamic acid and Harpagoside from the extract of Scrophularia ningpoensis Hemsl. as ligands binding to peroxisome proliferator-activated receptor γ. The proposed 2D NMR-based approach saves excess steps for sample processing and has a higher chance of detecting the weaker ligands in the complex extracts of medicinal herbs. We expect that this approach can be applied as an alternative to mining the potential ligands binding to a variety of target proteins from traditional Chinese medicines and herbal extracts.

Monosaccharide composition analysis by 2D quantitative gsHSQCi.

The physicochemical properties and biological activities of polysaccharides depend on their structures. Monosaccharide composition analysis is indispensable for the structural characterization of polysaccharides and is helpful in the quality control of polysaccharide preparation. Here, using a model mixture and tamarind seed polysaccharide as examples, we demonstrated that a quantitative 2D NMR method, gsHSQCi (three gradient-selective Heteronuclear Single Quantum Coherence spectra acquired with incremented repetition times, i = 1, 2, 3) can directly quantify a variety of monosaccharides in solution with adequate precision and accuracy, requiring no derivatization, postprocessing steps and column separation. Both anomeric and non-anomeric signals of monosaccharides can be utilized for content determination. More accurate quantification of fructose in a mixture containing nine monosaccharides is obtained, which is difficult to achieve by quantitative 1D 1HNMR and the common PMP-HPLC method (high-performance liquid chromatography through pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone) due to the peak overlapping and the poor derivatization efficiency, respectively. The results also revealed that Na[Fe(EDTA)] can serve as a proper relaxation-enhancing agent for saccharide samples to save experimental time. We expect that this approach can be applied as an alternative to analyzing the monosaccharide composition and be helpful in interpreting the structure of polysaccharides.

Left Ventricular Remodelling Associated with the Transient Elevated [68Ga]Ga-Pentixafor Activity in the Remote Myocardium Following Acute Myocardial Infarction.

BACKGROUND: Previous studies have initially reported accompanying elevated 2-deoxy-2[18F]fluoro-D-glucose ([18F]F-FDG) inflammatory activity in the remote area and its prognostic value after acute myocardial infarction (AMI). Non-invasive characterization of the accompanying inflammation in the remote myocardium may be of potency in guiding future targeted theranostics. [68Ga]Ga-Pentixafor targeting chemokine receptor 4 (CXCR4) on the surface of inflammatory cells is currently one of the promising inflammatory imaging agents. In this study, we sought to focus on the longitudinal evolution of [68Ga]Ga-Pentixafor activities in the remote myocardium following AMI and its association with cardiac function. METHODS: Twelve AMI rats and six Sham rats serially underwent [68Ga]Ga-Pentixafor imaging at pre-operation, and 5, 7, 14 days post-operation. Maximum and mean standard uptake value (SUV) and target-to-background ratio (TBR) were assessed to indicate the uptake intensity. Gated [18F]F-FDG imaging and immunofluorescent staining were performed to obtain cardiac function and responses of pro-inflammatory and reparative macrophages, respectively. RESULTS: The uptake of [68Ga]Ga-Pentixafor in the infarcted myocardium peaked at day 5 (all P = 0.003), retained at day 7 (all P = 0.011), and recovered at day 14 after AMI (P > 0.05), paralleling with the rise-fall pro-inflammatory M1 macrophages (P < 0.05). Correlated with the peak activity in the infarct territory, [68Ga]Ga-Pentixafor uptake in the remote myocardium on day 5 early after AMI significantly increased (AMI vs. Sham: SUVmean, SUVmax, and TBRmean: all P < 0.05), and strongly correlated with contemporaneous EDV and/or ESV (SUVmean and TBRmean: both P < 0.05). The transitory remote activity recovered as of day 7 post-AMI (AMI vs. Sham: P > 0.05). CONCLUSIONS: Corresponding with the peaked [68Ga]Ga-Pentixafor activity in the infarcted myocardium, the activity in the remote region elevated accordingly and led to contemporaneous left ventricular remodelling early after AMI. Further studies are warranted to clarify its clinical application potential.

HMGR and CHS gene cloning, characterizations and tissue-specific expressions in Polygala tenuifolia Willd.

Triterpenoid saponins and flavonoids have several pharmacological activities against P. tenuifolia. The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and chalcone synthase (CHS) are the rate-limiting enzymes of triterpenoid saponin and flavonoid biosynthesis, respectively. In this study, HMGR and CHS genes were cloned from P. tenuifolia, and their bioinformatics analyses and tissue-specific expression were investigated. The results showed that the HMGR and CHS genes were successfully cloned, separately named the PtHMGR gene (NCBI accession: MK424118) and PtCHS gene (NCBI accession: MK424117). The PtHMGR gene is 2323 bp long, has an open reading frame (ORF) of 1782 bp, and encods 593 amino acids. The PtCHS gene is 1633 bp long with an ORF of 1170 bp, encoding 389 amino acids. PtHMGR and PtCHS were both hydrophobic, not signal peptides or secreted proteins, containing 10 conserved motifs. PtHMGR and PtCHS separately showed high homology with HMGR and CHS proteins from other species, and their secondary structures mainly included α-helix and random curl. The tertiary structure of PtHMGR was highly similarity to that the template 7ULI in RCSB PDB with 92.0% coverage rate. The HMG-CoA-binding domain of PtHMGR is located at 173-572 amino acid residues, including five bound sites. The tertiary structure of PtCHS showed high consistency with the template 1I86 in RCSB PDB with 100% coverage rate, contained malonyl CoA and 4-coumaroyl-CoA linkers. The expression of PtHMGR and PtCHS is tissue-specific. PtHMGR transcripts were mainly accumulated in roots, followed by leaves, and least in stems, and were significantly positively correlated with the contents of total saponin and tenuifolin. PtCHS was highly expressed in the stems, followed by the leaves, with low expression in the roots. PtCHS transcripts showed a significant positive correlation with total flavonoids content, however, they were significantly negatively correlated with the content of polygalaxanthone III (a type of flavonoids). This study provided insight for further revealing the roles of PtHMGR and PtCHS.

Identification of Mudanjiang Phlebovirus in the Daxing'anling Region of China.

Mudanjiang phlebovirus (MJPV) is a newly discovered phlebovirus, initially detected from Ixodes persulcatus ticks in China in 2022. In this study, by next-generation sequencing (NGS) on a wide variety of ticks and wild small animals in China, we detected MJPV from I. persulcatus and Meriones meridianus. Additionally, we conducted RT-PCR and sequencing on 1815 adult ticks and 805 wild small mammals collected from eight provinces in China between 2017 and 2021. MJPV RNA-positive results were found in 0.22% (4/1815) of tick samples, as well as in 0.12% (1/805) of rodent samples. All positive detections were obtained from Heilongjiang and Inner Mongolia. Sequencing analysis revealed nucleotide similarities ranging from 98.23% to 99.11%, as well as amino acid similarities ranging from 99.12% to100%, between the current MJPV strain and previously reported strains of MJPV. Phylogenetic tree analysis demonstrated that the previously reported MJPV strain along with our two variants clustered together with other tick-borne phenuiviruses, indicating their close relationship within this viral group. This study represents the first detection of MJPV infection in wild rodents, expanding the known host range for this virus in the endemic regions.

Metagenomic survey reveals global distribution and evolution of microbial sialic acid catabolism.

Sialic acids comprise a varied group of nine-carbon amino sugars found mostly in humans and other higher metazoans, playing major roles in cell interactions with external environments as well as other cells. Microbial sialic acid catabolism (SAC) has long been considered a virulence determinant, and appears to be mainly the purview of pathogenic and commensal bacterial species associated with eukaryotic hosts. Here, we used 2,521 (pre-)assembled metagenomes to evaluate the distribution of SAC in microbial communities from diverse ecosystems and human body parts. Our results demonstrated that microorganisms possessing SAC globally existed in non-host associated environments, although much less frequently than in mammal hosts. We also showed that the ecological significance and taxonomic diversity of microbial SAC have so far been largely underestimated. Phylogenetic analysis revealed a strong signal of horizontal gene transfer among distinct taxa and habitats, and also suggested a specific ecological pressure and a relatively independent evolution history in environmental communities. Our study expanded the known diversity of microbial SAC, and has provided the backbone for further studies on its ecological roles and potential pathogenesis.

Effectiveness and influencing factors of online teaching among primary and secondary school teachers in China during the COVID-19: in depth interviews.

During COVID-19, online teaching was adopted in many countries and online teaching effectiveness attracted widespread attention. This study used in-depth interviews to explore the factors affecting online teaching efficacy of primary and secondary school teachers from teachers' perspectives, and used open coding, axial coding, and selective coding to analyze and organize the interview materials. Five thematic elements were finally derived, namely acceptance, professionalism, interactivity, instructional leadership and support, and home-school collaboration. From the teacher's perspective, acceptance, professionalism, and interactivity are closely related to the individual teacher, while instructional leadership and support, and home-school collaboration are two important external elements. This study explored the influencing factors of teaching effectiveness in different contexts, enriched the theory of teaching effectiveness, and provided practical support for the future development of online teaching.

A large-scale transcriptional analysis reveals herb-derived ginsenoside F2 suppressing hepatocellular carcinoma via inhibiting STAT3.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common type of cancer that shows great morbidity and mortality rates. However, there are limited available drugs to treat HCC. AIM: The present work focused on discovering the potential anti-HCC compounds from traditional Chinese medicine (TCM) by employing high-throughput sequencing-based high-throughput screening (HTS2) together with the liver cancer pathway-associated gene signature. METHODS: HTS2 assay was adopted for identifying herbs. Protein-protein interaction (PPI) network analysis and computer-aided drug design (CADD) were used to identify key targets and screen the candidate natural products of herbs. Molecular docking, network pharmacology analysis, western blotting, immunofluorescent staining, subcellular fractionation experiment, dual-luciferase reporter gene assay, surface plasmon resonance (SPR) as well as nuclear magnetic resonance (NMR) were performed to validate the ability of compound binding with key target and inhibiting its function. Moreover, cell viability, colony-forming, cell cycle assay and animal experiments were performed to examine the inhibitory effect of compound on HCC. RESULTS: We examined the perturbation of 578 herb extracts on the expression of 84 genes from the liver cancer pathway, and identified the top 20 herbs significantly reverting the gene expression of this pathway. Signal transducer and activator of transcription 3  (STAT3)  was identified as one of the key targets of the liver cancer pathway by PPI network analysis. Then, by analyzing compounds from top 20 herbs utilizing CADD, we found ginsenoside F2 (GF2) binds to STAT3 with high affinity, which was further validated by the results from molecular docking, SPR and NMR. Additionally, our results showed that GF2 suppresses the phosphorylation of Y705 of STAT3, inhibits its nuclear translocation, decreases its transcriptional activity and inhibits the growth of HCC in vitro and in vivo. CONCLUSION: Based on this large-scale transcriptional study, a number of anti-HCC herbs were identified. GF2, a compound derived from TCM, was found to be a chemical basis of these herbs in treating HCC. The present work also discovered that GF2 is a new STAT3 inhibitor, which is able to suppress HCC. As such, GF2 represents a new potential anti-HCC therapeutic strategy.

CsMYB15 positively regulates Cs4CL2-mediated lignin biosynthesis during juice sac granulation in navel orange.

'Lane Late', a late-maturing navel orange cultivar, is mainly distributed in the Three Gorges Reservoir area, which matures in the late March of the next year and needs overwintering cultivation. Citrus fruit granulation is a physiological disorder, which is characterized by lignification and dehydration of juice sac cells, seriously affecting the commercial value of citrus fruits. The pre-harvest granulation of late-maturing navel orange is main caused by low temperature in the winter, but its mechanism and regulation pattern remain unclear. In this study, a SG2-type R2R3-MYB transcription factor, CsMYB15, was identified from Citrus sinensis, which was significantly induced by both juice sac granulation and low temperature treatment. Subcellular localization analysis and transcriptional activation assay revealed that CsMYB15 protein was localized to the nucleus, and it exhibited transcriptional activation activity in yeast. Over-expression of CsMYB15 by stable transformation in navel orange calli and transient transformation in kumquat fruits and navel orange juice sacs significantly increased lignin content in the transgenic lines. Further, Yeast one hybrid, EMSA, and LUC assays demonstrated that CsMYB15 directly bound to the Cs4CL2 promoter and activated its expression, thereby causing a high accumulation of lignin in citrus. Taken together, these results elucidated the biological function of CsMYB15 in regulating Cs4CL2-mediated lignin biosynthesis, and provided novel insight into the transcriptional regulation mechanism underlying the juice sac granulation of late-maturing navel orange.

QSAR and molecular docking studies on designing potent inhibitors of SARS-CoVs main protease.

Background: Severe acute respiratory syndrome coronavirus (SARS-CoVs) have emerged as a global health threat, which had caused a high rate of mortality. There is an urgent need to find effective drugs against these viruses. Objective: This study aims to predict the activity of unsymmetrical aromatic disulfides by constructing a QSAR model, and to design new compounds according to the structural and physicochemical attributes responsible for higher activity towards SARS-CoVs main protease. Methods: All molecules were constructed in ChemOffice software and molecular descriptors were calculated by CODESSA software. A regression-based linear heuristic method was established by changing descriptors datasets and calculating predicted IC50 values of compounds. Then, some new compounds were designed according to molecular descriptors from the heuristic method model. The compounds with predicted values smaller than a set point were constantly screened out. Finally, the properties analysis and molecular docking were conducted to further understand the structure-activity relationships of these finalized compounds. Results: The heuristic method explored the various descriptors responsible for bioactivity and gained the best linear model with R2 0.87. The success of the model fully passed the testing set validation, proving that the model has both high statistical significance and excellent predictive ability. A total of 5 compounds with ideal predicted IC50 were found from the 96 newly designed derivatives and their properties analyze was carried out. Molecular docking experiments were conducted for the optimal compound 31a, which has the best compound activity with good target protein binding capability. Conclusion: The heuristic method was quite reliable for predicting IC50 values of unsymmetrical aromatic disulfides. The present research provides meaningful guidance for further exploration of the highly active inhibitors for SARS-CoVs.

First report of Neopestalotiopsis rosae causing leaf blight on Shatangju in southern China.

Shatangju (Citrus reticulata Blanco cv. Shatangju) belongs to genus Citrus and was cultivated extensively in southern China. In April 2022, a leaf blight-like symptom (firstly brown spots appeared on infecting leaves, then these brown spots extended, finally the whole leaves displayed blight-like symptom) was observed on 5%~10% of Shatangju seedlings (around five hundreds in total) in an orchard located in Wuhan city, Hubei, China. Diseased leaves from three seedlings were collected and cut into pieces (0.2 to 0.5 cm). These pieces were surface-sterilized using 75% ethanol for 3 min, rinsed with sterile distilled water for several times, then placed on potato dextrose agar (PDA) and incubated at 26°C with 12-h light/dark cycle. Over 20 pieces plated, wherein 30% were identified as Colletotrichum fructicola, 60% as Neopestalotiopsis spp., and 10% developed saprophytes. C. fructicola was a known pathogen on citrus, thus Neopestalotiopsis spp. was further investigated. Eight single-conidium colonies of the Neopestalotiopsis spp. were obtained, wherein STJ-8 was chosen as a representative for further study. The average growth rate of STJ-8 was 15.1±0.5 mm/day (n=5). Fungal colonies produced white cottony mycelium with abundant black acervuli distributed in concentric rings 6-8 days after planting, which ranged from 342.3 to 710.5 µm in diameter (n=100). Conidia were fusoid, five cells, four septa with average dimensions of 25.36×5.47 µm (n=100). Basal and apical cells were hyaline, wherein three middle cells were brown with darker septa. The apical cell was cylindrical with two to three transparent accessory filaments (13.7 to 30.5 µm in length, n=80). Basal cell was conic with an appendage (4.1 to 8.8 µm in length, n=40). Partial sequences of internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF-1α), and ß-tubulin (TUB2) were amplified with reported primers (White et al. 1990; Lee et al. 2006; Maharachchikumbura et al. 2014), sequenced, and submitted to GenBank (accession nos. ITS: OP236541; TEF-1α: OP250124; TUB2:OP263094). BLASTn results showed 100% identity with the corresponding sequences of Neopestalotiopsis rosae. A multilocus phylogenetic analysis showed STJ-8 was closest to N. rosae. Thus, STJ-8 was identified as N. rosae. Pathogenicity tests were performed on one-year-old Shatangju seedlings and detached primary leaves by inoculating needle-wounded leaves with seven days old 5-mm mycelial plugs/acervuli (about 5000 spores) of STJ-8. Control seedlings/leaves were inoculated with 5-mm PDA plugs/sterile water drops. All inoculated detached leaves were cultured at same the place with STJ-8 cultured, while inoculated seedlings were put in a growth chamber at 26°C under a 16-h light/dark cycle (60% humidity). Symptoms developed on all inoculated leaves (except healthy control) 2 and 4 days post-inoculation by mycelial plugs and acervuli, respectively. N. rosae was re-isolated from the inoculated leaves, confirming Koch's postulates. N. rosae has been reported to cause diseases on various plants worldwide (Rebollar-Alviter et al. 2020; Xavier et al. 2021; Lawrence et al. 2022). In China, N. rosae has been reported to cause leaf spot/blight on pecan and strawberry (Wu et al. 2021; Gao et al. 2022), which caused great loss on these crops. To our knowledge, this is the first report of N. rosae causing leaf disease on citrus. Our study is important for developing control strategies against N. rosae in future.

Organocatalytic Enantioselective Synthesis of Axially Chiral N,N'-Bisindoles.

This study establishes the first organocatalytic enantioselective synthesis of axially chiral N,N'-bisindoles via chiral phosphoric acid-catalyzed formal (3+2) cycloadditions of indole-based enaminones as novel platform molecules with 2,3-diketoesters, where de novo indole-ring formation is involved. Using this new strategy, various axially chiral N,N'-bisindoles were synthesized in good yields and with excellent enantioselectivities (up to 87 % yield and 96 % ee). More importantly, this class of axially chiral N,N'-bisindoles exhibited some degree of cytotoxicity toward cancer cells and was derived into axially chiral phosphine ligands with high catalytic activity. This study provides a new strategy for enantioselective synthesis of axially chiral N,N'-bisindoles using asymmetric organocatalysis and is the first to realize the applications of such scaffolds in medicinal chemistry and asymmetric catalysis.

Impacts of Climate Change and Land Use/Cover Change on the Net Primary Productivity of Vegetation in the Qinghai Lake Basin.

The Qinghai Lake Basin acts as a natural barrier, preventing the western desert from spreading eastward. This is an important link in preserving the ecological stability of the northeastern region of the Qinghai-Tibet Plateau (QTP). Therefore, quantitative research into the net primary productivity (NPP) of vegetation and its driving force in the Qinghai Lake Basin is required. The effects of land use/cover change (LUCC) and climate change on NPP in the Qinghai Lake Basin were studied using R-contribution ratio and partial correlation analysis methods using MOD17A3H products, Land Use/Land Cover (LULC) data, and meteorological data. (1) The LULC of the Qinghai Lake Basin showed a trend that "the area of grassland, cultivated land, and unused land continued to decrease, while the area of other LULC types increased" from 2000 to 2020, according to the study's findings. Grassland, water bodies, construction land, and unused land dominated the mutual transformation of LULC types. (2) The NPP of the basin showed a growing trend, with a growth rate of 3.93 gC·m-2·a-1 before 2010 and 0.88 gC·m-2·a-1 after 2010. Significant regional heterogeneity was found in NPP, with gradients decreasing from southeast to northwest. (3) The impact of LUCC on overall NPP changes had gradually increased. Climate change has been the primary driver of NPP changes in the Qinghai Lake Basin over the last 20 years.

Saikosaponin D improves chemosensitivity of glioblastoma by reducing the its stemness maintenance.

Objective: Chemotherapy is one of the important adjuvant methods for the treatment of glioblastoma (GBM), and chemotherapy resistance is a clinical problem that neurooncologists need to solve urgently. It is reported that Saikosaponin D (SSD), an active component of Bupleurum chinense, had various of antitumor activities and could also enhance the chemosensitivity of liver cancer and other tumors. However, it is not clear whether it has an effect on the chemosensitivity of glioma and its specific mechanism. Methods: The CCK8 assay, Wound healing assay and Matrigel invasion assay were used to detect the effect of SSD on the phenotype of GBM cells. We detected the effect of SSD on the chemosensitivity of GSM by Flow cytometry, LDH content and MTT assay. Then, we used cell plate cloning, semi-quantitative PCR and western blotting experiments to detect the effect of SSD on the stem potential of GBM cells. Finally, the effect of SSD on the chemosensitivity of GBM and its potential mechanism were verified by nude mouse experiments in vivo. Results: firstly, we found that SSD could partially inhibit the malignant phenotype of LN-229 cells, including inhibiting migration, invasion and apoptosis, and increasing the apoptosis rate and lactate dehydrogenase (LDH) release of LN-229 cells under the treatment of temozolomide (TMZ), that is to say, increasing the chemotherapy effect of TMZ on the cells. In addition, we unexpectedly found that SSD could partially inhibit the colony forming ability of LN-229 cells, which directly related to the stemness maintenance potential of cancer stem cells. Subsequently, our results showed that SSD could inhibit the gene and protein expression of stemness factors (OCT4, SOX2, c-Myc and Klf4) in LN-229 cells. Finally, we verified that SSD could improve the chemotherapy effect of TMZ by inhibiting the stem potential of glioblastoma in vivo nude mice. Conclusion: this research can provide a certain theoretical basis for the application of SSD in the chemotherapy resistance of GBM and its mechanism of action, and provide a new hope for the clinical treatment of glioblastoma.

A ß-glucan from Aureobasidium pullulans enhanced the antitumor effect with rituximab against SU-DHL-8.

ß-Glucans affect the immune system and have antitumor activity; therefore, they are being investigated as immunomodulators and chemotherapeutic adjuvants. In this study, we investigated a specific ß-glucan, exopolysaccharide (EPS-1) derived from Aureobasidium pullulans (CGMCC 20363), to investigate its impact on the efficacy of rituximab against diffuse large B cell lymphoma (SU-DHL-8 cells) in vitro and in vivo. The results show that compared to rituximab alone, EPS-1 enhanced the inhibition of SU-DHL-8, had antitumor effects in vivo, and improved the response of the immune system of the host. RNA sequencing results reveal that EPS-1 had a chemotactic effect on T cells through the JAK-STAT signaling pathway and recruited immune cells into tumor tissues. EPS-1 also played an antitumor role through the mitochondrial and death receptor Fas-related apoptotic pathways. In summary, EPS-1 may be an effective adjuvant to treat diffuse large B cell lymphoma in combination with rituximab.

First report of Fusarium oxysporum and Fusarium solani causing root rot on trifoliate orange rootstock in China.

Trifoliate orange (Poncirus trifoliata L) is a thorny tree of the Rue family, which is extensively used as citrus rootstock in China. In January 2021, several leaf yellowing, declining, and wilting citrus seedlings grafted on trifoliate orange rootstock with rotted main roots were observed in orchards located in Wuhan city, Hubei, China. In old orchards, the incidence of diseased roots was approximately 90%. Diseased roots from seven plants were collected and cut into small pieces (0.2 to 0.5 cm). These pieces were then surface-sterilized using 0.1% mercury bichloride for 3 min, 75% ethanol for 3 min, rinsed with sterile distilled water for several times, and then placed on potato dextrose agar (PDA) supplemented with 0.05% lactic acid (v/v), and incubated at at 25±2°C in dark. Fifty-threesingle-conidium isolates with morphological characteristics similar to Fusarium spp. were obtained (Leslie and Summerell 2006), which displayed two kinds of colony morphology. Thirty isolates showed white to orange-white abundant aerial mycelium in rings and acquired a yellow to orange pigmentation, tweenty-three isolates showed white to pink, fluffy aerial mycelium in rings and acquired an orange to red pigmentation. Isolate WG-1 and HrmY-9 from each group were used for future identification. The average colony growth rate of WG-1 and HrmY-9 on PDA was 0.95±0.06 and 0.69±0.11 mm/day, n=4, respectively. WG-1 produced numerous oval, unicellular microconidia without septa, 4.03-9.87×1.01-5.13 µm, n=80 and very few macroconidia with two to four septa, narrowed at both ends, 11.08-22.64×1.67-4.91 µm, n=30. HrmY-9 produced numerous curved macroconidia with three to four septa, 18.03-37.33×2.16-7.8 µm, n=80, microconidia were unicellular, oval, and 5.33-16.19×1.74-6.51 µm, n=50. Sequences of internal transcribed spacer (ITS), translation elongation factor 1-alpha (EF-1α), and DNA-directed RNA polymerase largest subunit (RPB1) genes were amplified with the primers ITS1/ITS4, EF1a-F/EF1a-R, and RPB1-F5/RPB1-R8, respectively (White et al. 1990, O'Donnell et al. 1998, O'Donnell et al. 2010), sequenced and deposited in GenBank. Sequences of isolate WG-1 (GenBank accession No. ON045437, ON063232 and ON089664) and HrmY-9 (GenBank accession No. ON045438, ON063233 and ON089665) were 100% identical with the corresponding sequences of Fusarium oxysporum (OM876904, JF430180, and MT568959) and F. solani (MT605584, MK617767, and MT305110), respectively. Based on above results, WG-1 and HrmY-9 was identified as F. oxysporum and F. solani, respectively. Pathogenicity test were performed on healthy one-year-old trifoliate orange seedlings by dipping their injured roots into conidial suspension (50 ml, 1×106 conidia/mL) for 1 h and the rest of conidial suspension was added to the pot after replanting to make sure the inoculum was in contact with the roots. Roots of control plants were inoculated with sterilized water. All experiments were repeated twice. All plants were cultured at 26°C under a 16-h light/dark cycle. Typical symptoms developed on most of inoculated seedlings two months post inoculation. No disease symptoms appeared on control plants. Same colonies were reisolated from the inoculated roots, confirming Koch's postulates. To our knowledge, this is the first report of F. oxysporum and F. solani causing root rot on trifoliate orange rootstock in China. The identification of F. oxysporum and F. solani as the causal agents of the observed root rot on trifoliate orange rootstock is critical to the prevention and control of this disease in the future.

Discovery of a Novel Small-Molecule Inhibitor Disrupting TRBP-Dicer Interaction against Hepatocellular Carcinoma via the Modulation of microRNA Biogenesis.

MicroRNAs (miRNAs) are key players in human hepatocellular carcinoma (HCC) tumorigenesis. Therefore, small molecules targeting components of miRNA biogenesis may provide new therapeutic means for HCC treatment. By a high-throughput screening and structural simplification, we identified a small molecule, CIB-3b, which suppresses the growth and metastasis of HCC in vitro and in vivo by modulating expression profiles of miRNAome and proteome in HCC cells. Mechanistically, CIB-3b physically binds to transactivation response (TAR) RNA-binding protein 2 (TRBP) and disrupts the TRBP-Dicer interaction, thereby altering the activity of Dicer and mature miRNA production. Structure-activity relationship study via the synthesis of 45 CIB-3b derivatives showed that some compounds exhibited a similar inhibitory effect on miRNA biogenesis to CIB-3b. These results support TRBP as a potential therapeutic target in HCC and warrant further development of CIB-3b along with its analogues as a novel therapeutic strategy for the treatment of HCC.

Solution structure of c-FLIP death effector domains.

The formation of death-inducing signaling complex (DISC) and death effector domain (DED) filament initiates extrinsic apoptosis. Recruitment and activation of procaspase-8 at the DISC are regulated by c-FLIP. The interaction between c-FLIP and procaspase-8 is mediated by their tandem DEDs (tDED). However, the structure of c-FLIPtDED and how c-FLIP interferes with procaspase-8 activation at the DISC remain elusive. Here, we solved the monomeric structure of c-FLIPtDED (F114G) at near physiological pH by solution nuclear magnetic resonance (NMR). Structural superimposition reveals c-FLIPtDED (F114G) adopts a structural topology similar to that of procaspase-8tDED. Our results provide a structural basis for understanding how c-FLIP interacts with procaspase-8 and the molecular mechanisms of c-FLIP in regulating cell death.

Mild Hypothermia Promotes Ischemic Tolerance and Survival of Neural Stem Cell Grafts by Enhancing Global SUMOylation.

Cerebral infarct penumbra due to hypoxia and toxin accumulation is not conducive to the transplantation of neural stem cells (NSCs), although mild hypothermia can improve the local microenvironment of the ischemic penumbra and exert neuroprotective effects. However, insufficient understanding of the molecular mechanism by which mild hypothermia protects the brain limits widespread clinical application. This study evaluated the molecular mechanism of mild hypothermia-induced brain protection from the perspective of global protein small ubiquitin-like modifier (SUMO) modification, with the aim of improving NSC transplant survival rates in the penumbra to enhance neurological function. NSCs from neonatal rats were extracted to detect the effects of hypoxia and mild hypothermia on SUMOylation modification levels, cell stemness, and hypoxia-induced injury. Overexpression and knockdown of UBC9 in NSCs were used to evaluate their ability to maintain stemness and withstand hypoxic injury. Finally, a rat middle cerebral artery occlusion (MCAO) model was used to verify the effect of mild hypothermia treatment and UBC9 overexpression on neural function of NSCs following penumbra transplantation in rats. Results showed that hypoxia and mild hypothermia promoted both the SUMOylation modification and maintenance of NSC stemness. Overexpression of UBC9 enhanced the abilities of NSCs to maintain stemness and resist hypoxic injury, while UBC9 knockdown had the opposite effect. Following transplantation into the ischemic penumbra of MCAO model rats, mild hypothermia and Ubc9-overexpressing NSCs significantly reduced cerebral infarct areas and improved neurological function. In conclusion, this study demonstrated that global protein SUMOylation is an important molecular mechanism for NSCs to tolerate hypoxia, and mild hypothermia can further increase the degree of global SUMOylation to enhance the hypoxia tolerance of NSCs, which increases their survival during transplantation in situ and ability to perform nerve repair in the penumbra of cerebral infarction.

LINC00586 Represses ASXL1 Expression Thus Inducing Epithelial-To-Mesenchymal Transition of Colorectal Cancer Cells Through LSD1-Mediated H3K4me2 Demethylation.

Colorectal cancer (CRC) is a major public health problem on a global scale by virtue of its relatively high incidence. The transition of tumor cells from an epithelial to a mesenchymal-like phenotype, so-called epithelial-to-mesenchymal transition (EMT), is a key hallmark of human cancer metastasis, including CRC. Understanding the signaling events that initiate this phenotypic switch may provide opportunities to limit the metastasis of CRC. In this study, we aim to identify long non-coding RNA (lncRNA) mediated epigenetic regulation under the context of CRC. 54 paired samples of tumor tissues and surrounding non-tumor tissues were collected from CRC patients. Cultured human CRC cells HCT116 and LoVo were assayed for their viability and migration using CCK-8 tests and transwell migration assays. The expression of EMT-specific markers (E-cadherin, N-cadherin and vimentin) was analyzed biochemically by RT-qPCR and immunoblot analyses. Interaction among LINC00586, LSD1, and ASXL1 was determined by RNA immunoprecipitation and chromatin immunoprecipitation. In vivo analysis of LINC00586 was performed in nude mice xenografted with HCT116 cells. LINC00586 was overexpressed in CRC tissues and associated with patient survival. LINC00586 knockdown repressed HCT116 and LoVo cell viability, migration, their phenotypic switch from epithelial to a mesenchymal, and tumorigenesis in vivo. We demonstrated LINC00586 recruited the LSD1 into the ASXL1 promoter region and epigenetically silenced the ASXL1 expression. An ASXL1 gene resisting to LINC00586 attack was demonstrated in cultured HCT116 and LoVo cells and mouse xenograft models of human CRC. Overall, discovery of the LINC00586/LSD1/ASXL1 axis partially explains epigenetic mechanism regulating EMT in CRC, providing a therapeutic target to limit CRC metastasis.