Human UDP-glucuronosyltransferase 1As catalyze aristolochic acid D O-glucuronidation to form a lesser nephrotoxic glucuronide.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochic acids (AAs) are naturally occurring nitro phenanthrene carboxylic acids primarily found in plants of the Aristolochiaceae family. Aristolochic acid D (AAD) is a major constituent in the roots and rhizomes of the Chinese herb Xixin (the roots and rhizomes of Asarum heterotropoides F. Schmidt), which is a key material for preparing a suite of marketed Chinese medicines. Structurally, AAD is nearly identical to the nephrotoxic aristolochic acid I (AAI), with an additional phenolic group at the C-6 site. Although the nephrotoxicity and metabolic pathways of AAI have been well-investigated, the metabolic pathway(s) of AAD in humans and the influence of AAD metabolism on its nephrotoxicity has not been investigated yet. AIM OF THE STUDY: To identify the major metabolites of AAD in human tissues and to characterize AAD O-glucuronidation kinetics in different enzyme sources, as well as to explore the influence of AAD O-glucuronidation on its nephrotoxicity. MATERIALS AND METHODS: The O-glucuronide of AAD was biosynthesized and its chemical structure was fully characterized by both 1H-NMR and 13C-NMR. Reaction phenotyping assays, chemical inhibition assays, and enzyme kinetics analyses were conducted to assess the crucial enzymes involved in AAD O-glucuronidation in humans. Docking simulations were performed to mimic the catalytic conformations of AAD in human UDP-glucuronosyltransferases (UGTs), while the predicted binding energies and distances between the deprotonated C-6 phenolic group of AAD and the glucuronyl moiety of UDPGA in each tested human UGT isoenzyme were measured. The mitochondrial membrane potentials (MMP) and reactive oxygen species (ROS) levels in HK-2 cells treated with either AAI, or AAD, or AAD O-glucuronide were tested, to elucidate the impact of O-glucuronidation on the nephrotoxicity of AAD. RESULTS: AAD could be rapidly metabolized in human liver and intestinal microsomes (HLM and HIM, respectively) to form a mono-glucuronide, which was purified and fully characterized as AAD-6-O-ß-D-glucuronide (AADG) by NMR. UGT1A1 was the predominant enzyme responsible for AAD-6-O-glucuronidation, while UGT1A9 contributed to a lesser extent. AAD-6-O-glucuronidation in HLM, HIM, UGT1A1 and UGT1A9 followed Michaelis-Menten kinetics, with the Km values of 4.27 µM, 9.05 µM, 3.87 µM, and 7.00 µM, respectively. Docking simulations suggested that AAD was accessible to the catalytic cavity of UGT1A1 or UGT1A9 and formed catalytic conformations. Further investigations showed that both AAI and AAD could trigger the elevated intracellular ROS levels and induce mitochondrial dysfunction and in HK-2 cells, but AADG was hardly to trigger ROS accumulation and mitochondrial dysfunction. CONCLUSION: Collectively, UGT1A-catalyzed AAD 6-O-glucuronidation represents a crucial detoxification pathway of this naturally occurring AAI analogs in humans, which is very different from that of AAI.

Identification and validation of mitophagy-related signatures as a novel prognostic model for colorectal cancer.

Background: Colorectal cancer (CRC) is one of the most commonly diagnosed cancers in the world. Mitophagy is associated with tumorigenesis and development of malignancy. However, the specific role of mitophagy has yet not been systematically explored in CRC. Methods: The RNA-sequencing dataset of CRC from The Cancer Genome Atlas (TCGA) and microarray data of gene expression profiles of CRC from Gene Expression Omnibus (GEO) were downloaded. Mitophagy-related gene sets were obtained from the Pathway Unification database. The package "limma" was used for differential gene expression analysis. Kaplan-Meier (KM) survival analyses were utilized to evaluate the prognostic value of the mitophagy regulators. Single-sample gene set enrichment analysis (ssGSEA) was used to estimate the infiltrating immune cells and the activity of immune response. The ConsensusClusterPlus algorithm was used to determine mitophagy-related subtypes. Principal component analysis (PCA) was used to create composite measurement of mitophagy scores. The R packages "survminer" and "ReGlot" were used to plot the nomogram and calibration curves. Results: Integrated analysis of the GEO and TCGA databases revealed some common differentially expressed genes (DEGs) in CRC. MFN2, UBB, PINK1, and PRKN were significantly downregulated in CRC samples as compared to normal samples, and other genes were significantly upregulated in CRC samples. KM survival analyses showed that high expression of ATG12 and MAP1LC3B predicted a poor prognosis, whereas high expression of TOMM22 and TOMM40 predicted a better prognosis. Mitophagy showed significant correlation with immune-related pathways in CRC samples. We identified 2 distinct CRC subtypes with different mitophagy accumulation, of which subtype B had better prognosis and immune activity. The mitophagy score may be employed as a new and efficient clinical predictor in conjunction with other clinical indicators to predict the prognosis of CRC patients. Conclusions: We systematically investigated the CRC heterogeneity with reference to mitophagy based on bioinformatics analyses, and the findings of this study might provide some guidance for future research into potential biomarkers for diagnosis and prognosis prediction of CRC patients.

Xanthohumol ameliorates drug-induced hepatic ferroptosis via activating Nrf2/xCT/GPX4 signaling pathway.

BACKGROUND: As a canonical iron-dependent form of regulated cell death (RCD), ferroptosis plays a crucial role in chemical-induced liver injuries. Previous studies have demonstrated that xanthohumol (Xh), a natural prenylflavonoid isolated from hops, exhibits anti-inflammatory, anti-antioxidative and hepatoprotective properties. However, the regulatory effects of Xh on hepatic ferroptosis and the underlying mechanism have not yet been fully elucidated. PURPOSE: To investigate the hepatoprotective effects of Xh against drug-induced liver injury (DILI) and the regulatory effects of Xh on hepatic ferroptosis, as well as to reveal the underlying molecular mechanisms. METHODS/STUDY DESIGN: The hepatoprotective benefits of Xh were investigated in APAP-induced liver injury (AILI) mice and HepaRG cells. Xh was administered intraperitoneally to assess its in vivo effects. Histological and biochemical studies were carried out to evaluate liver damage. A series of ferroptosis-related markers, including intracellular Fe2+ levels, ROS and GSH levels, the levels of MDA, LPO and 4-HNE, as well as the expression levels of ferroptosis-related proteins and modulators were quantified both in vivo and in vitro. The modified peptides of Keap1 by Xh were characterized utilizing nano LC-MS/MS. RESULTS: Xh remarkably suppresses hepatic ferroptosis and ameliorates AILI both in vitro and in vivo, via suppressing Fe2+ accumulation, ROS formation, MDA generation and GSH depletion, these observations could be considerably mitigated by the ferroptosis inhibitor ferrostatin-1 (Fer-1). Mechanistically, Xh could significantly activate the Nrf2/xCT/GPX4 signaling pathway to counteract AILI-induced hepatocyte ferroptosis. Further investigations showed that Xh could covalently modify three functional cysteine residues (cys151, 273, 288) of Keap1, which in turn, reduced the ubiquitination rates of Nrf2 and prolonged its degradation half-life. CONCLUSIONS: Xh evidently suppresses hepatic ferroptosis and ameliorates AILI via covalent modifying three key cysteines of Keap1 and activating Nrf2/xCT/GPX4 signaling pathway.

Defect-engineering improves the activity of Metal-Organic frameworks for catalyzing hydroboration of Alkynes: A combination of experimental investigation and Density functional theory calculations.

Defect-engineered metal-organic frameworks (DEMOFs) are emerging advanced materials. The construction of DEMOFs is of great significance; however, DEMOF-based catalysis remains unexplored. (E)-vinylboronates, an important building block for asymmetric synthesis, can be synthesized via the hydroboration of alkynes. However, the lack of high-performance catalysts considerably hinders their synthesis. Herein, a series of DEHKUST-1 (HKUST = Hong Kong University of Science and Technology) (Da-f) catalysts with missing occupation of linkers at Cu nodes were designed by partially replacing benzene-1,3,5-tricarboxylate (H3BTC) with defective connectors of pyridine-3,5-dicarboxylate (PYDC) to efficiently promote the hydroboration of alkynes. Results showed that the Dd containing 0.8 doping ratio of PYDC exhibited remarkable catalytic activity than the defect-free HKUST-1. This originated from the improved accessibility for reactants towards the Lewis acid active Cu sites of DEHKUST-1 due to the presence of plenty of rooms next to the Cu sites and enhanced coordination ability in such 'defective' HKUST-1. Dd had high selectivity (>99 %) and yield (>96 %) for (E)-vinylboronates and extensive functional group compatibility for terminal alkynes. Density functional theory (DFT) calculations were performed to elucidate the mechanism of hydroboration. Compared with that of defect-free HKUST-1, the low energy barrier of DEHKUST-1 can be attributed to the lower coordination number of Cu sites and enhanced accessibility of Cu active sites towards reagents.

Refractive index SPR sensor with high sensitivity and wide detection range using tapered silica fiber and photopolymer coating.

This paper introduces a surface plasmon resonance (SPR) sensor using tapered silica fiber and photopolymer coating for enhanced refractive index (RI) detection. Tapering the silica fiber to a diameter of 10 µm ensures the evanescent wave leaks into a 1.8-µm thick photopolymer film, which increases the average waveguide RI and broadens the RI detection range accordingly. A 50-nm thick single-side gold film is coated on the photopolymer film, exciting SPR and causing less light transmission loss than a double-side gold film. The method avoids the complex microfabrication processes of conventional polymer optical fiber SPR sensors, while the waveguide RI can be controlled by altering the curing time of the photopolymer during fabrication. The sensor has an overall sensitivity of 3686.25 nm/RIU, enabling RI detection of 1.333 - 1.493. Moreover, the sensor has an ultrahigh sensitivity of 6422.9 nm/RIU in the RI range of 1.423 - 1.493. The temperature response is about 1.43 nm/°C at 20 - 50 °C, which has little impact on RI detection. Finally, we demonstrate that the sensor can grade the severity of hepatic steatosis by measuring the RIs of cytoplasm/triglyceride emulsions with superior sensing performance.

Preclinical study of pachyman inducing ferroptosis against ovarian cancer: Biological targets and underlying mechanisms.

Ferroptosis has gained extreme purpose in targeting cancer treatment. Poria cocos Wolf, a traditional Chinese herb, has potential anticancer properties, but the action and mechanism against ovarian cancer remain undetailed. Pachyman (Poria cocos polysaccharides) refers to the pharmacologically bioactive ingredients rich in Poria cocos. This study aimed to identify the potent actions and the network mechanisms of pachyman against ovarian cancer through preclinical analysis. Online-accessible database or platform was employed to predict candidate genes and core targets associated with ferroptosis in pachyman against ovarian cancer. Enrichment analyses were used to characterize the functional action and signaling mechanism in pachyman to treat ovarian cancer. Molecular docking imitation was conducted for verification of core target proteins. Network analysis uncovered that there were 30 mutual and 13 core genes targeting ferroptosis in pachyman and/against ovarian cancer, and additional enrichment analysis characterized that these core genes may act synergistically through multiple biological processes and molecular pathways associated with ferroptosis, including anti-inflammatory action, immunoregulation, and microenvironment modulation. The strongest affinities in core target proteins between pachyman and sarcoma (SRC), signal transducer, and activator of transcription 3 (STAT3) were further validated using molecular docking method. In conclusion, pachyman may induce antiovarian cancer potentials via regulating ferroptosis-associated biological functions and pharmacological mechanisms based on current bioinformatics findings. We reason that pachyman, the beneficial nutraceuticals, may be used clinically for future application in ovarian cancer treatment.

Early clinical observation of supra-hemodiafiltration with endogenous reinfusion in the treatment of uremic pruritus.

BACKGROUND: To evaluate the clinical efficacy of supra-hemodiafiltration with endogenous reinfusion (Supra-HFR) for pruritus in uremic maintenance hemodialysis (HD) patients and explore the possible mechanism. METHODS: This study prospectively included 60 patients with uremia who underwent maintenance hemodialysis and developed pruritus. Patients were randomly divided into a study group (30 cases) and a control group (30 cases). Patients in the study group underwent dialysis once a week with Supra-HFR and twice a week with HD. The group received HD dialysis 3 times a week. Visual analog scales (VAS) scores, 5-D itch scale scores, and 12-Item Pruritus Severity Scale (12-PSS) were used to evaluate the itching degree of patients. Quality of life was assessed using KDTA and SF-36 scores. Blood levels of hypersensitive C-reactive protein, calcium ion (Ca2+), phosphorus ion (P3+ ), free parathyroid hormone (iPTH), and ß2-microglobulin (ß2-MG) were compared between the two groups before treatment and at follow-up 24 weeks after treatment. RESULTS: Before treatment, there was no significant difference in VAS, 5-D itch scale, and 12-PSS score between the study group and the control group (all p > 0.05). After 24 weeks of treatment, the VAS score of the study group (2.82 ± 0.91) was significantly lower than that of the control group (7.47 ± 1.32, p < 0.001), the 5-D itch scale score of the study group (9.47 ± 2.34) was significantly lower than that of the control group (18.53 ± 4.02, p < 0.001), the 12-PSS score of the study group (11.20 ± 1.81) was significantly lower than that of the control group (16.47 ± 2.09, p < 0.001). KDTA of the study group (64.17 ± 8.07 vs. 47.83 ± 13.46, p < 0.001) and SF-36 scores (65.37 ± 6.28 vs. 55.90 ± 14.28, p = 0.002) were significantly higher than that in the control group. The levels of hs-CRP, P3+ , iPTH, and ß2-MG in the study group after treatment were lower than those before treatment, and lower than those in the control group after treatment (all p < 0.05). CONCLUSIONS: The Supra-HFR can effectively reduce the itching symptoms of uremia patients and improve their quality of life.

Effect of ticagrelor on the function of tunneled cuffed catheter in maintenance hemodialysis patients.

OBJECTIVE: To observe the effect of ticagrelor on the function of a tunneled cuffed catheter (TCC) in maintenance hemodialysis (MHD) patients. METHODS: Eighty MHD patients (control group: 39 cases, observation group: 41 cases) using TCC as vascular access were enrolled from January 2019 to October 2020 in this prospective study. Patients in the control group were routinely treated with aspirin for antiplatelet therapy, while patients in the observation group were treated with ticagrelor. The catheter life time, catheter dysfunction, coagulation function, and antiplatelet drug-related adverse events of the two groups were recorded. RESULTS: The median life time of TCC in the control group was significantly higher than that in the observation group. Moreover, the log rank test showed that the difference was statistically significant (p < 0.001). CONCLUSION: Ticagrelor may reduce the incidence of catheter dysfunction and prolong the life time of the catheter by preventing and reducing the thrombosis of TCC in MHD patients, without obvious side effects.

Construction and Manipulation of Serial Gradient Dilution Array on a Microfluidic Slipchip for Screening and Characterizing Inhibitors against Human Pancreatic Lipase.

Obesity is one of the foremost public health concerns. Human pancreatic lipase (hPL), a crucial digestive enzyme responsible for the digestion of dietary lipids in humans, has been validated as an important therapeutic target for preventing and treating obesity. The serial dilution technique is commonly used to generate solutions with different concentrations and can be easily modified for drug screening. Conventional serial gradient dilution is often performed with tedious multiple manual pipetting steps, where it is difficult to precisely control fluidic volumes at low microliter levels. Herein, we presented a microfluidic SlipChip that enabled formation and manipulation of serial dilution array in an instrument-free manner. With simple slipping steps, the compound solution could be diluted to seven gradients with the dilution ratio of 1:1 and co-incubated with the enzyme (hPL)-substrate system for screening the anti-hPL potentials. To ensure complete mixing of solution and diluent during continuous dilution, we established a numerical simulation model and conducted an ink mixing experiment to determine the mixing time. Furthermore, we also demonstrated the serial dilution ability of the proposed SlipChip using standard fluorescent dye. As a proof of concept, we tested this microfluidic SlipChip using one marketed anti-obesity drug (Orlistat) and two natural products (1,2,3,4,6-penta-O-galloyl-ß-D-glucopyranose (PGG) and sciadopitysin) with anti-hPL potentials. The IC50 values of these agents were calculated as 11.69 nM, 8.22 nM and 0.80 µM, for Orlistat, PGG and sciadopitysin, respectively, which were consistent with the results obtained by conventional biochemical assay.

The GZnC1 variant from common wild rice influences grain Zn content.

Zinc (Zn) deficiency, caused by inadequate Zn intake in the human diet, has serious health implications. Rice (Oryza sativa) is the staple food in regions with a high incidence of Zn deficiency, so raising Zn levels in rice grain could help alleviate Zn deficiency. The wild relatives of cultivated rice vary widely in grain Zn content and thus are suitable resources for improving this trait. However, few loci underlying grain Zn content have been identified in wild rice relatives. Here, we identified a major quantitative trait locus for grain Zn content, Grain Zn Content 1 (qGZnC1), from Yuanjiang common wild rice (Oryza rufipogon Griff.) using map-based cloning. Down-regulating GZnC1 expression reduced the grain Zn content, whereas the presence of GZnC1 had the opposite effect, indicating that GZnC1 is involved in grain Zn content in rice. Notably, GZnC1 is identical to a previously reported gene, EMBRYO SAC ABORTION 1 (ESA1), involved in seed setting rate. The mutation in GZnC1/ESA1 at position 1819 (T1819C) causes delayed termination of protein translation. In addition, GZnC1 is specifically expressed in developing panicles. Several genes related to Zn-transporter genes were up-regulated in the presence of GZnC1. Our results suggest that GZnC1 activates Zn transporters to promote Zn distribution in panicles. Our work thus sheds light on the genetic mechanism of Zn accumulation in rice grain and provides a new genetic resource for improving Zn content in rice.

Bioactive tigliane diterpenoids from the latex of Euphorbia fischeriana.

Latex is a type of sticky endogenous fluids derived from diverse plants including Euphorbia fischeriana, and is of great scientific and commercial values. In the current study, it was demonstrated that the latex extracted from E. fischeriana strongly respelled the growth of cotton bollworm, Helicoverpa armigera. Using spectroscopic methods, HPLC, and GC-MS analyses, six aliphatic tigliane diterpenoids were isolated from the latex of E. fischeriana, among which three compounds (2, 3, and 5) were new. Two major compounds (1 and 4) exhibited remarkable antifeedant activity against H. armigera, with EC50 values at 2.59 and 15.32 µg/cm2, respectively. In addition, the quantification analysis of diterpenoids in different organs indicated that 4 was the most abundant constituent and was highly accumulated in the latex. Collectively, the current study highlighted that the diterpenoids in latex of E. fischeriana had a considerable antifeedant function against H. armigera, which might be employed for the future development of natural insecticides for organic farming.

308-nm Excimer Laser Plus Platelet-Rich Plasma for Treatment of Stable Vitiligo: A Prospective, Randomized Case-Control Study.

PURPOSE: 308-nm excimer laser has a confirmed treatment effect on vitiligo. Platelet-rich plasma (PRP) is an autologous preparation which contains a variety of growth factors. The effect of 308-nm excimer laser combined with PRP on vitiligo has been rarely reported. This study investigated the effect of PRP combined with 308-nm excimer laser on stable vitiligo. PATIENTS AND METHODS: A total of 60 patients with localized stable vitiligo who received treatment at Beijing Friendship Hospital and Xi'an Vitiligo Specialist Hospital between May 2019 and January 2020 were consecutively enrolled. They were equally randomized into three groups according to different treatment methods: intradermal PRP injection (group I), 308-nm excimer laser alone (group II), and 308-nm excimer laser plus PRP injection (group III). All treatments lasted for 3 months. At 3 months after treatment, clinical assessments were performed in terms of the visual analogue scale (VAS) score, repigmentation response and side effects. RESULTS: The VAS scores showed significant differences among the three groups (P<0.001), with the highest score in group III, followed by group II and then group I. Repigmentation responses also showed significant differences among the groups (P<0.001), and the best effect was observed in group III. No side effects were reported in any of the groups. CONCLUSION: The effect of PRP combined with 308-nm excimer laser on stable vitiligo is significantly better than that of PRP and 308-nm excimer laser alone. It is safe and satisfactorily tolerant.

Basilic vein transposition-radial artery fistula created using the no-touch technique
.

OBJECTIVE: To compare the functions and complications of forearm basilic vein transposition-arteriovenous fistula (BVT-AVF) created using the no-touch technique with that of conventional radiocephalic arteriovenous fistula (RC-AVF). MATERIALS AND METHODS: The no-touch technique was used to created basilic vein transposition-radial artery fistula in 22 patients. Another 30 patients received surgeries for RC-AVF. The fistula functions and complications were compared between these two groups. RESULTS: The two groups did not differ significantly in the incidence of postoperative bleeding, limb swelling, infection, steal syndrome, fistula thrombosis, fistula aneurysm, fistula flow, fistula maturation time, Kt/v, and fistula median survival. CONCLUSION: Forearm BVT-AVF created by the no-touch technique is a good alternative access for patients in whom the standard arteriovenous fistula cannot be established.

Sustained low-efficiency diafiltration is superior to hemodialysis in promoting renal function recovery in elderly wasp sting victims with stage III acute kidney injury: a retrospective study.

Objective: To study the efficacy and safety of sustained low-efficiency diafiltration (SLEDf) versus hemodialysis (HD) for patients with wasp stings who developed stage III acute kidney injury (AKI). Methods: We retrospectively analyzed the clinical data of consecutive patients who developed AKI following wasp stings. All eligible patients received renal replacement therapy in combination with hemoperfusion. Thereafter, blood purification therapy and HD were performed with a volumetrically controlled machine and 1.7 m2 surface, Fresenius Polysulfone HD filter and SLEDf was undertaken with a volumetrically controlled machine and 1.3 m2 surface, Fresenius Polysulfone HD filter. Results: Forty patients developed stage III AKI following wasp stings, including 14 patients that received SLEDf and 26 patients underwent HD. Thirteen patients were aged less than 60 years and underwent HD (group I), 27 patients were aged at least 60 years, including 13 patients undergoing HD (group II) and 14 patients receiving SLEDf (group III). Groups I and II completed 150 and 162 sessions of HD, respectively, and group III completed 156 sessions of sustained low-efficiency blood purification therapy, including 50 sessions of SLEDf. The time to return to normal serum creatinine levels was 38.8 ± 2.7 days for group I, 47.2 ± 5.3 days for group II, and 39.2 ± 3.3 days for group III. A statistically significant difference was observed in time to normal serum creatinine levels among the three groups. Conclusion: Elderly wasp victims have more severe illness than younger wasp victims and SLEDf is safe and superior to HD in recovery of renal function of elderly wasp victims.

Evaluation on treatment of sustained low-efficiency hemodialysis against patients with multiple organ dysfunction syndrome following wasp stings.

BACKGROUND: To evaluate the treatment of sustained low-efficiency hemodialysis (SLED) against patients with multiple organ dysfunction syndrome (MODS) following wasp stings. METHODS: Clinical data of 35 patients with MODS following wasp stings were retrospectively analysed. These patients were divided into three groups according to the treatment strategy used: 1) hemodialysis (HD) group, 2) continuous veno-venous hemofiltration (CVVH)/HD group, and 3) SLED/HD group. The clinical parameters, treatment outcome, and safety findings were compared among the three groups. RESULTS: The recovery rate (76.92% vs 77.78% vs 91.67%, p = 0.621) and mortality rate (15.38% vs 11.11% vs 8.33%, p = 0.999) were similar among the three groups. When compared to the HD group, patients treated with CVVH/HD or SLED/HD required a shorter period of time to enter into polyuria stage [(24.7 ± 4.3) days vs (20.2 ± 4.7) days vs (18.2 ± 3.0) days, F = 9.11, p = 0.0007], and required a shorter time for serum creatinine to return to normal [(45.7 ± 13.4) days vs (33.1 ± 9.4) days vs (31.9 ± 9.8), F = 5.83, p = 0.0069]; while such parameters had no significant differences between SLED/HD group and CVVH/HD group. The adverse events of hypotension and arrhythmia were found in the HD group, while no adverse events were reported in the SLED/HD and CVVH/HD groups. There was no significant difference in the cost of blood purification treatment between the SLED/HD group and HD group. CONCLUSION: The use of SLED, CVVH and HD provided a comparable recovery and survival rates in patients with MODS secondary to wasp stings. Compared to HD, the use of SLED is recommended as a treatment strategy because of the efficacy on recover of renal function, satisfactory safety outcome, as well as the reasonable treatment cost.

ESA1 Is Involved in Embryo Sac Abortion in Interspecific Hybrid Progeny of Rice.

The emergence of sterile individuals in the hybrid backcross progeny of wild and cultivated rice limits the use of wild rice alleles for improving cultivated rice, but the molecular mechanisms underlying this sterility remain unclear. Here, we identified the semisterile introgression line YIL42, derived from a cross between the indica rice variety Teqing (Oryza sativa) and Oryza rufipogon accession YJCWR (Yuanjiang common wild rice), which exhibits semisterility. Using positional cloning, we isolated EMBRYO SAC ABORTION 1 (ESA1), which encodes a nuclear-membrane localized protein containing an armadillo repeat domain. A mutation in ESA1 at position 1819 (T1819C) converts a stop codon into an Arg (R) codon, causing delayed termination of protein translation. Analysis of transgenic lines indicated that the difference in ESA1 protein structure between O. rufipogon-derived ESA1 and Teqing-derived esa1 affects female gamete abortion during early mitosis. Fertility investigation and expression analysis indicated that the interaction between ESA1 T1819 and unknown gene(s) of Teqing affects spikelet fertility of the hybrid backcross progeny. The ESA1 T1819 allele is present in O. rufipogon but absent in O. sativa, suggesting that variation in ESA1 may be associated with interspecific hybrid incompatibility between wild and cultivated rice. Our findings provide insight into the molecular mechanism underlying female sterility, which is useful for improving the panicle seed setting rate of rice and for developing a strategy to overcome interspecific hybrid sterility between cultivated rice and wild rice.

Cytotoxic Terpenoids from the Roots of Dracocephalum taliense.

A chemical investigation of methanol extract from the roots of Dracocephalum taliense led to the isolation of a new aromatic abietane diterpenoid, 12-methoxy-18-hydroxy-sugiol (1), and one highly-oxygenated ursane triterpenoid, 2α,3α-dihydroxy-11α,12α-epoxy-urs-28,13ß-olide (2), together with 15 known natural products (3-17). Among these, compounds 1-13 and 15-17 were detected for the first time in the genus of Dracocephalum. The structures of all of these isolates were determined by extensively spectroscopic analyses. In the anti-inflammatory assay, compounds 1 and 2 had no obvious inhibitory activity on the release of cytokine IL-2 in lipopolysaccharide-induced RAW 264.7 macrophages. However, compound 2 exhibited significant cytotoxic activity against cell lines HepG2 (IC50 = 6.58 ± 0.14 µM) and NCI-H1975 (IC50 = 7.17 ± 0.26 µM).

Essentiality drives the orientation bias of bacterial genes in a continuous manner.

Studies had found that bacterial genes are preferentially located on the leading strands. Subsequently, the preferences of essential genes and highly expressed genes were compared by classifying all genes into four groups, which showed that the former has an exclusive influence on orientation. However, only some functional classes of essential genes have this orientation bias. Nevertheless, previous studies only performed comparative analyzes by differentiating the orientation bias extent of two types of genes. Thus, it is unclear whether the influence of essentiality on strand bias works continuously. Herein, we found a significant correlation between essentiality and orientation bias extent in 19 of 21 analyzed bacterial genomes, based on quantitative measurement of gene essentiality (or fitness). The correlation coefficient was much higher than that derived from binary essentiality measures (essential or non-essential). This suggested that genes with relatively lower essentiality, i.e., conditionally essential genes, also have some orientation bias, although it is weaker than that of absolutely essential genes. The results demonstrated the continuous influence of essentiality on orientation bias and provided details on this visible structural feature of bacterial genomes. It also proved that Geptop and IFIM could serve as useful resources of bacterial gene essentiality, particularly for quantitative analysis.

IFIM: a database of integrated fitness information for microbial genes.

Knowledge of an organism's fitness for survival is important for a complete understanding of microbial genetics and effective drug design. Current essential gene databases provide only binary essentiality data from genome-wide experiments. We therefore developed a new database that Integrates quantitative Fitness Information for Microbial genes (IFIM). The IFIM database currently contains data from 16 experiments and 2186 theoretical predictions. The highly significant correlation between the experiment-derived fitness data and our computational simulations demonstrated that the computer-generated predictions were often as reliable as the experimental data. The data in IFIM can be accessed easily, and the interface allows users to browse through the gene fitness information that it contains. IFIM is the first resource that allows easy access to fitness data of microbial genes. We believe this database will contribute to a better understanding of microbial genetics and will be useful in designing drugs to resist microbial pathogens, especially when experimental data are unavailable. Database URL: http://cefg.uestc.edu.cn/ifim/ or http://cefg.cn/ifim/

Nitrification characteristics of nitrobacteria immobilized in waterborne polyurethane in wastewater of corn-based ethanol fuel production.

A technology to achieve stable and high ammonia nitrogen removal rates for corn distillery wastewater (ethanol fuel production) treatment has been designed. The characteristics of nitrifying bacteria entrapped in a waterborne polyurethane (WPU) gel carrier were evaluated after acclimation. In the acclimation period, nitrification rates of WPU-immobilized nitrobacteria were monitored and polymerase chain reaction (PCR) was also carried out to investigate the change in ammonium-oxidizing bacteria. The results showed that the pellet nitrification rates increased from 21 to 228 mg-N/(L-pellet x hr) and the quantity of the ammonia oxidation bacteria increased substantially during the acclimation. A continuous ammonia removal experiment with the anaerobic pond effluent of a distillery wastewater system was conducted with immobilized nitrifying bacteria for 30 days using an 80 L airlift reactor with pellets at a fill ratio of 15% (V/V). Under the conditions of 75 mg/L influent ammonia, hydraulic retention time (HRT) of 3.7-5.6 hr, and dissolved oxygen (DO) of 4 mg/L, the effluent ammonia concentration was lower than 10 mg/L and the ammonia removal efficiency was 90%. While the highest ammonia removal rate, 162 mg-N/(L-pellet x hr), was observed when the HRT was 1.3 hr.