Search

Sporopollenin is the major component of the outer pollen wall (sexine). It is synthesized using a pathway of approximately eight genes in Arabidopsis ( Arabidopsis thaliana ). MALE STERILITY188 (MS188) and its direct upstream regulator ABORTED MICROSPORES (AMS) are two transcription factors essential for tapetum development. Here, we show that all the sporopollenin biosynthesis proteins are specifically expressed in the tapetum and are secreted into anther locules. MS188, a MYB transcription factor expressed in the tapetum, directly regulates the expression of POLYKETIDE SYNTHASE A ( PKSA ), PKSB , MALE STERILE2 ( MS2 ), and a CYTOCHROME P450 gene ( CYP703A2 ). By contrast, the expression of CYP704B1 , ACYL-COA SYNTHETASE5 ( ACOS5 ), TETRAKETIDE a-PYRONE REDUCTASE1 ( TKPR1 ) and TKPR2 are significantly reduced in ams mutants but not affected in ms188 mutants. However, MS188 but not AMS can activate the expression of CYP704B1 , ACOS5 , and TKPR1 In ms188 , dominant suppression of MS188 homologs reduced the expression of these genes, suggesting that MS188 and other MYB family members play redundant roles in activating their expression. The expression of some sporopollenin synthesis genes ( PKSA , PKSB , TKPR2 , CYP704B1 , and ACOS5 ) was rescued when MS188 was expressed in ams Therefore, MS188 is a key regulator for activation of sporopollenin synthesis, and AMS and MS188 may form a feed-forward loop that activates the expression of the sporopollenin biosynthesis pathway for rapid pollen wall formation., (© 2018 American Society of Plant Biologists. All rights reserved.)

Background: In Arabidopsis, the tapetum and microsporocytes are critical for pollen formation. Previous studies have shown that ARF17 is expressed in microsporocytes and tetrads and directly regulates tetrad wall synthesis for pollen formation. ARF17 is the direct target of miR160, and promoterARF17::5mARF17 (5mARF17/WT) transgenic plants, which have five silent mutations within the miR160-complementary domain, are sterile., Results: Here, we found that ARF17 is also expressed in the tapetum, which was defective in arf17 mutants. Compared with arf17 mutants, 5mARF17/WT plants had abnormal tapetal cells and tetrads but were less vacuolated in the tapetum. Immunocytochemical assays showed that the ARF17 protein over-accumulated in tapetum, microsporocytes and tetrads of 5mARF17/WT plants at early anther stages, but its expression pattern was not affected during anther development. 5mARF17 driven by its native promoter did not rescue the arf17 male-sterile phenotype. The expression of 5mARF17 driven by the tapetum-specific promoter A9 led to a defective tapetum and male sterility in transgenic plants. These results suggest that the overexpression of ARF17 in the tapetum and microsporocytes of 5mARF17/WT plants leads to male sterility. Microarray data revealed that an abundance of genes involved in transcription and translation are ectopically expressed in 5mARF17/WT plants., Conclusions: Our work shows that ARF17 plays an essential role in anther development and pollen formation, and ARF17 expression under miR160 regulation is critical for its function during anther development.

Banded iron formations (BIFs) in Archean cratons provide important "geologic barcodes" for the global correlation of Precambrian sedimentary records. Here we report the first finding of late Archean BIFs from the Yangtze Craton, one of largest Precambrian blocks in East Asia with an evolutionary history of over 3.3 Ga. The Yingshan iron deposit at the northeastern margin of the Yangtze Craton, displays typical features of BIF, including: (i) alternating Si-rich and Fe-rich bands at sub-mm to meter scales; (ii) high SiO 2  + Fe 2 O 3total contents (average 90.6 wt.%) and Fe/Ti ratios (average 489); (iii) relative enrichment of heavy rare earth elements and positive Eu anomalies (average 1.42); (iv) and sedimentary Fe isotope compositions (δ 56 Fe IRMM-014 as low as -0.36‰). The depositional age of the BIF is constrained at ~2464 ± 24 Ma based on U-Pb dating of zircon grains from a migmatite sample of a volcanic protolith that conformably overlied the Yingshan BIF. The BIF was intruded by Neoproterozoic (805.9 ± 4.7 Ma) granitoids that are unique in the Yangtze Craton but absent in the North China Craton to the north. The discovery of the Yingshan BIF provides new constraints for the tectonic evolution of the Yangtze Craton and has important implications in the reconstruction of Pre-Nuna/Columbia supercontinent configurations.

Objectives: A randomized, parallel controlled, open-label clinical trial was conducted to evaluate the effect of a botanic compound berberine (BBR) on NAFLD., Methods: A randomized, parallel controlled, open-label clinical trial was conducted in three medical centers (NIH Registration number: NCT00633282). A total of 184 eligible patients with NAFLD were enrolled and randomly received (i) lifestyle intervention (LSI), (ii) LSI plus pioglitazone (PGZ) 15mg qd, and (iii) LSI plus BBR 0.5g tid, respectively, for 16 weeks. Hepatic fat content (HFC), serum glucose and lipid profiles, liver enzymes and serum and urine BBR concentrations were assessed before and after treatment. We also analyzed hepatic BBR content and expression of genes related to glucose and lipid metabolism in an animal model of NAFLD treated with BBR., Results: As compared with LSI, BBR treatment plus LSI resulted in a significant reduction of HFC (52.7% vs 36.4%, p = 0.008), paralleled with better improvement in body weight, HOMA-IR, and serum lipid profiles (all p<0.05). BBR was more effective than PGZ 15mg qd in reducing body weight and improving lipid profile. BBR-related adverse events were mild and mainly occurred in digestive system. Serum and urine BBR concentrations were 6.99ng/ml and 79.2ng/ml, respectively, in the BBR-treated subjects. Animal experiments showed that BBR located favorably in the liver and altered hepatic metabolism-related gene expression., Conclusion: BBR ameliorates NAFLD and related metabolic disorders. The therapeutic effect of BBR on NAFLD may involve a direct regulation of hepatic lipid metabolism., Trial Registration: ClinicalTrials.gov NCT00633282.

Purpose: We aimed to optimize diffusion-weighted imaging (DWI) acquisitions for normal pancreas at 3.0 Tesla., Materials and Methods: Thirty healthy volunteers were examined using four DWI acquisition techniques with b values of 0 and 600 s/mm2 at 3.0 Tesla, including breath-hold DWI, respiratory-triggered DWI, respiratory-triggered DWI with inversion recovery (IR), and free-breathing DWI with IR. Artifacts, signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) of normal pancreas were statistically evaluated among different DWI acquisitions., Results: Statistical differences were noticed in artifacts, SNR, and ADC values of normal pancreas among different DWI acquisitions by ANOVA (P <0.001). Normal pancreas imaging had the lowest artifact in respiratory-triggered DWI with IR, the highest SNR in respiratory-triggered DWI, and the highest ADC value in free-breathing DWI with IR. The head, body, and tail of normal pancreas had statistically different ADC values on each DWI acquisition by ANOVA (P < 0.05)., Conclusion: The highest image quality for normal pancreas was obtained using respiratory-triggered DWI with IR. Normal pancreas displayed inhomogeneous ADC values along the head, body, and tail structures.

Specific determination/monitoring of trace mercury ions (Hg(2+)) in environmental water is of significant importance for drinking safety. Complementarily to conventional inductively coupled plasma mass spectrometry and atomic emission/absorption spectroscopy, several methods, i.e., electrochemical, fluorescent, colorimetric, and surface enhanced Raman scattering approaches, have been developed recently. Despite great success, many inevitably encounter the interferences from other metal ions besides the complicated procedures and sophisticated equipments. Here we present a molecular-gap device for specific determination of trace Hg(2+) in both standardized solutions and environmental samples based on conductivity-modulated glutathione dimer. Through a self-assembling technique, a thin film of glutathione monolayer capped Au nanoparticles is introduced into 2.5 μm-gap-electrodes, forming numerous double molecular layer gaps. Notably, the fabricated molecular-gap device shows a specific response toward Hg(2+) with a low detection limit actually measured down to 1 nM. Theoretical calculations demonstrate that the specific sensing mechanism greatly depends on the electron transport ability of glutathione dimer bridged by heavy metal ions, which is determined by its frontier molecular orbital, not the binding energy.

A 57-year-old man presented with intermittent dull abdominal pain after a period of 1 year. Abdominal computed tomography (CT) was performed. Except for the endoscopy, the work-up for possible medical causes remained inconclusive. An open-abdomen, partial surgical excision of the stomach was performed after the unsuccessful endoscopic resection. The pathology report revealed a glomus tumor of the stomach. Importantly, glomus tumors of the stomach are rare and are almost always benign. Therefore, the most important current role of imaging associated with the diagnostic approach and therapeutic plan for a glomus tumor is to differentiate it from other gastric submucosal tumors (SMTs). We report this case with representative radiologic findings, including CT and endoscopic ultrasound (EUS) reports, and also correlate them with clinical and pathologic presentations that can help in the early detection and differentiation of gastric SMTs from other SMTs. As such, the purpose of this report is to provide a better understanding of relevant CT and EUS features. Alternative treatments should be considered carefully according to the imaging results.

Objective: To explore the liver disease spectrum in patients with type 2 diabetes (T2DM) and the risk factors of non-alcoholic fatty liver disease (NAFLD)., Methods: From September 2009 to October 2011, 1069 hospitalized patients with T2DM in Department of Endocrinology and Metabolism were involved in the study. The history informations, results of laboratory examination, hepatic ultrasound and hepatic proton magnetic resonance spectrum ((1)H MRS) of all patients were collected to analysis., Results: (1) The detectable rate of raised liver enzymes in T2DM patients was 28.7% (307/1069), composed mainly of NAFLD (39.4%, 121/307). After excluding the factors such as alcoholic abuse, viral hepatitis, the detect rate of raised liver enzymes in T2DM patients was 26.9% (185/688). (2) The detectable rate of fatty liver by ultrasound in T2DM patients was 56.7% (500/882), composed mainly of NAFLD (72.6%, 363/500), and the detectable rate of NAFLD was 58.0% (363/626). (3) The detectable rate of fatty liver by hepatic (1)H MRS was 72.8% (227/312), composed mainly of NAFLD (69.6%, 158/227). The detectable rate of NAFLD was 69.6% (158/227). (4) Of the three methods for diagnosing NAFLD, (1)H MRS had the highest detectable rate, followed by ultrasound, and the hepatic enzymes was the lowest. Set the hepatic (1)H MRS as gold diagnosing standard of NAFLD, the combination of hepatic enzymes and ultrasound increase the sensitivity. The optional cut-off points of ALT were 19.7 U/L (male, ROCAUC = 0.689, P < 0.01) and 17.0 U/L (female, ROCAUC = 0.727, P < 0.01). (5) Logistic stepwise regression analysis showed sex, BMI, hemoglobin, fasting C-peptide and uric acid (OR = 3.803, 1.195, 1.037, 2.896, 1.011, all P < 0.05) were positively correlated with NAFLD, and diabetes duration (OR = 0.948, P < 0.05) was positively correlated with NAFLD independently., Conclusions: The detectable rate of fatty liver was high in T2DM which was composed mainly of NAFLD. High abnormal liver enzymes detectable rate indicated that NAFLD with T2DM are prone to NASH.

Accurate measures of liver fat content are essential for investigating the role of hepatic steatosis in the pathophysiology of multiple metabolic disorders. No traditional imaging methods can accurately quantify liver fat content. [(1)H]-magnetic resonance spectroscopy (MRS) is restricted in large-scale studies because of the practical and technological issues. Previous attempts on computer-aided ultrasound quantification of liver fat content varied in method, and the ultrasound quantitative parameters measured from different ultrasound machines were hardly comparable. We aimed to establish and validate a simple and propagable method for quantitative assessment of liver fat content based on the combination of standardized ultrasound quantitative parameters, using [(1)H]-MRS as gold standard. Totally 127 participants were examined with both ultrasonography (US) and [(1)H]-MRS. Ultrasound hepatic/renal echo-intensity ratio (H/R) and ultrasound hepatic echo-intensity attenuation rate (HA) were obtained from ordinary ultrasound images using computer program. Both parameters were standardized using a tissue-mimicking phantom before analysis. Standardized ultrasound H/R and HA were positively correlated with the liver fat content by [(1)H]-MRS (r = 0.884, P < 0.001 and r = 0.711, P < 0.001, respectively). Linear regression analysis showed ultrasound H/R could modestly predict the amount of liver fat (adjusted explained variance 78.0%, P < 0.001). The addition of ultrasound HA slightly improved the adjusted explained variance to 79.8%. Difference of estimated liver fat contents between different ultrasound machines and operators was reasonably well. Thus, computer-aided US is a valid method to estimate liver fat content and can be applied extensively after standardization of ultrasound quantitative parameters.

Objective: To study the relationship between liver fat content (LFC) and liver enzymes in individuals with various statuses of glucose metabolism., Methods: A total of 109 subjects including with impaired glucose regulation (IGR) (n = 31), newly diagnosed type 2 diabetes (NT2DM) (n = 31) and normal glucose tolerance (NGT) (n = 47) were recruited. The level of LFC was measured by (1)H magnetic resonance spectroscopy ((1)H-MRS) to study the relationship between liver fat content (LFC) and alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP) and γ-glutamyltransferase (GGT). The receiver operating characteristic curve (ROC) was employed to obtain the optimal cut-off point of ALT to predict the occurrence of nonalcoholic fatty liver disease (NAFLD)., Results: (1) The levels of LFC were progressively raised in NGT, IGR and NT2DM groups respectively [3.83 (2.35 - 7.59)%, 12.82 (8.10 - 21.37)% and 21.99 (11.89 - 34.43)%, P < 0.01]; (2) the subjects were divided into four subgroups by the method of LFC quartile. And quartile subgroups Q1-4 were associated with the increase of LFC. Waist, BMI, systolic blood pressure, triglyceride, total cholesterol, fasting plasma glucose, OGTT 2 h postprandial glucose and HOMA-IR had a rising trend from Q2. But HDL-C showed a declining trend from Q2; (3) ALT and GGT significantly increased from Q3 (P < 0.01) while AST and AKP significantly increased in Q4 (P < 0.01); (4) adjusted by gender, age and body mass index (BMI), LFC was positively correlated with AST (r = 0.329, P < 0.05), ALT (r = 0.454) and GGT (r = 0.378) (All P < 0.01). But it was negatively correlated with AST/ALT (r = -0.364, P < 0.01); (5) the analysis of stepwise regression demonstrated that LFC was a predictor of ALT, AST, GGT and AST/ALT; (6) ALT had a ROC(AUC) of 0.813 (male) and 0.769 (female) (All P < 0.01). The optimal cut-off point of 23.5 U/L (male) and 17.5 U/L (female) might predict the occurrence of NAFLD., Conclusions: Liver enzymes are correlated with LFC even in normal range. The optimal cut-off point of 23.5 U/L (male) and 17.5 U/L (female) might predict the occurrence of NAFLD. The current used ALT upper limit could underestimate the NAFLD.