Antagonism between abscisic acid and ethylene in Arabidopsis acts in parallel with the reciprocal regulation of their metabolism and signaling pathways

Although abscisic acid (ABA) and ethylene have antagonistic functions in the control of plant growth and development, including seed germination and early seedling development, it remains unknown whether a convergent point exists between these two signaling pathways or whether they operate in parallel in Arabidopsis thaliana. To elucidate this issue, four ethylene mutants, ctr1, ein2, ein3, and ein6, were crossed with aba2 (also known as gin1-3) to generate double mutants. Genetic epistasis analysis revealed that all of the resulting double mutants displayed aba2 mutant phenotypes with a small plant size and wiltiness when grown in soil or on agar plates. Further ethylene sensitivity or triple response analyses demonstrated that these double mutants also retained the ctr1 or ein mutant phenotypes, showing ethylene constitutive triple and insensitive responses, respectively. Our current data therefore demonstrate that ABA and ethylene act in parallel, at least in primary signal transduction pathways. Moreover, by microarray analysis we found that an ACC oxidase (ACO) was significantly upregulated in the aba2 mutant, whereas the 9-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3) gene in ein2 was upregulated, and both the ABSCISIC ACID INSENSITIVE1 (ABI1) and cytochromeP450, family 707, subfamily A, polypeptide 2 (CYP707A2) genes in etr1-1 were downregulated. These data further suggest that ABA and ethylene may control the hormonal biosynthesis, catabolism, or signaling of each other to enhance their antagonistic effects upon seed germination and early seedling growth

Bis{1-[(E)-o-tolyl­diazen­yl]-2-naphtho­l­ato}copper(II)

In the title complex, [Cu(C17H13N2O)2], the CuII atom is tetra­coordinated by two N atoms and two O atoms from two bidentate 1-[(E)-o-tolyl­diazen­yl]-2-naphtho­late ligands, forming a slightly distorted square-planar environment. The two N atoms and two O atoms around the CuII atom are trans to each other, with an O—Cu—O bond angle of 177.00 (9)° and an N—Cu—N bond angle of 165.63 (10)°. The average distances between the CuII atom and the coordinated O and N atoms are 1.905 (2) and 1.995 (2)Å, respectively

Profiling of Substrate Specificity of SARS-CoV 3CLpro

BACKGROUND: The 3C-like protease (3CL(pro)) of severe acute respiratory syndrome-coronavirus is required for autoprocessing of the polyprotein, and is a potential target for treating coronaviral infection. METHODOLOGY/PRINCIPAL FINDINGS: To obtain a thorough understanding of substrate specificity of the protease, a substrate library of 198 variants was created by performing saturation mutagenesis on the autocleavage sequence at P5 to P3' positions. The substrate sequences were inserted between cyan and yellow fluorescent proteins so that the cleavage rates were monitored by in vitro fluorescence resonance energy transfer. The relative cleavage rate for different substrate sequences was correlated with various structural properties. P5 and P3 positions prefer residues with high β-sheet propensity; P4 prefers small hydrophobic residues; P2 prefers hydrophobic residues without β-branch. Gln is the best residue at P1 position, but observable cleavage can be detected with His and Met substitutions. P1' position prefers small residues, while P2' and P3' positions have no strong preference on residue substitutions. Noteworthy, solvent exposed sites such as P5, P3 and P3' positions favour positively charged residues over negatively charged one, suggesting that electrostatic interactions may play a role in catalysis. A super-active substrate, which combined the preferred residues at P5 to P1 positions, was found to have 2.8 fold higher activity than the wild-type sequence. CONCLUSIONS/SIGNIFICANCE: Our results demonstrated a strong structure-activity relationship between the 3CL(pro) and its substrate. The substrate specificity profiled in this study may provide insights into a rational design of peptidomimetic inhibitors

Transport through a quantum ring, a dot and a barrier embedded in a nanowire in magnetic field

We investigate the transport through a quantum ring, a dot and a barrier embedded in a nanowire in a homogeneous perpendicular magnetic field. To be able to treat scattering potentials of finite extent in magnetic field we use a mixed momentum-coordinate representation to obtain an integral equation for the multiband scattering matrix. For a large embedded quantum ring we are able to obtain Aharanov-Bohm type of oscillations with superimposed narrow resonances caused by interaction with quasi-bound states in the ring. We also employ scattering matrix approach to calculate the conductance through a semi-extended barrier or well in the wire. The numerical implementations we resort to in order to describe the cases of weak and intermediate magnetic field allow us to produce high resolution maps of the ``near field'' scattering wave functions, which are used to shed light on the underlying scattering processes.Comment: RevTeX, 13 pages with included postscript figures, high resolution version available at http://hartree.raunvis.hi.is/~vidar/Rann/VG_04.pd

Genome-Wide DNA Methylation Profiling in Human Breast Tissue by Illumina TruSeq Methyl Capture EPIC Sequencing and Infinium MethylationEPIC Beadchip Microarray

A newly-developed platform, the Illumina TruSeq Methyl Capture EPIC library prep (TruSeq EPIC), builds on the content of the Infinium MethylationEPIC Beadchip Microarray (EPIC-array) and leverages the power of next-generation sequencing for targeted bisulphite sequencing. We empirically examined the performance of TruSeq EPIC and EPIC-array in assessing genome-wide DNA methylation in breast tissue samples. TruSeq EPIC provided data with a much higher density in the regions when compared to EPIC-array (~2.74 million CpGs with at least 10X coverage vs ~752 K CpGs, respectively). Approximately 398 K CpGs were common and measured across the two platforms in every sample. Overall, there was high concordance in methylation levels between the two platforms (Pearson correlation r = 0.98, P \u3c 0.0001). However, we observed that TruSeq EPIC measurements provided a wider dynamic range and likely a higher quantitative sensitivity for CpGs that were either hypo- or hyper-methylated (β close to 0 or 1, respectively). In addition, when comparing different breast tissue types TruSeq EPIC identified more differentially methylated CpGs than EPIC-array, not only out of additional sites interrogated by TruSeq EPIC alone, but also out of common sites interrogated by both platforms. Our results suggest that both platforms show high reproducibility and reliability in genome-wide DNA methylation profiling, while TruSeq EPIC had a significant improvement over EPIC-array regarding genomic resolution and coverage. The wider dynamic range and likely higher precision of the estimates by the TruSeq EPIC may lead to the identification of novel differentially methylated markers that are associated with disease risk

Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia

INTRODUCTION: High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence. METHOD AND RESULTS: Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001). CONCLUSION: Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH

A putative lytic transglycosylase tightly regulated and critical for the EHEC type three secretion

Open reading frame l0045 in the pathogenic island of enterohemorrhagic Escherichia coli O157:H7 has been predicted to encode a lytic transglycosylase that is homologous to two different gene products encoded by the same bacteria at loci away from the island. To deduce the necessity of the presence in the island, we created an l0045-deleted strain of EHEC and observed that both the level of cytosolic EspA and that of the other type III secreted proteins in the media were affected. In a complementation assay, a low level-expressing L0045 appeared to recover efficiently the type III secretion (TTS). On the other hand, when l0045 was driven to express robustly, the intracellular levels of representative TTS proteins were severely suppressed. This suppression is apparently caused by the protein of L0045 per se since introducing an early translational termination codon abolished the suppression. Intriguingly, the authentic L0045 was hardly detected in all lysates of EHEC differently prepared while the same construct was expectedly expressed in the K-12 strain. A unique network must exist in EHEC to tightly regulate the presence of L0045, and we found that a LEE regulator (GrlA) is critically involved in this regulation

Hypertension is an important predictor of recurrent colorectal adenoma after screening colonoscopy with adenoma polypectomy

AbstractBackgroundThe predictors of recurrent colorectal adenoma have not been fully examined. This study aimed to evaluate the predictors of recurrent colorectal adenoma after initial screening colonoscopy with adenoma polypectomy.MethodsA retrospective cohort study was conducted at the Taipei Veterans General Hospital from 2003 to 2011. After screening, 356 patients who had undergone two consecutive colonoscopies with colorectal adenoma polypectomy at the initial colonoscopy were enrolled. The recurrence group was patients with recurrent colorectal adenoma at the second colonoscopy, whereas the nonrecurrence group was patients without recurrence. Anthropometric data, biochemical tests, metabolic comorbidities, and adenoma characteristics at initial colonoscopy were compared between the two groups. Cox proportional hazard regression analysis was conducted to identify the predictors of recurrent colorectal adenoma.ResultsDuring a mean follow-up interval of 3.07 ± 1.42 years, 94 patients (26.4%) were in the recurrence group, 262 patients (73.6%) were in the nonrecurrence group. The recurrence group was older, had a wider waist circumference, higher levels of serum alanine aminotransferase (ALT) and triglyceride, a higher prevalence of smoking, nonalcoholic fatty liver disease, metabolic syndrome, and hypertension, and a higher occurrence of initial multiply-located adenomas when compared with the nonrecurrence group (p < 0.05). Cox regression analysis showed that hypertension, smoking, higher ALT level (>40 IU/mL), and multiply-located adenomas were independent predictors for recurrent colorectal adenoma. The risk of recurrent adenoma increased when hypertension was combined with smoking, high ALT level, or multiply-located adenomas.ConclusionHypertension is an important predictor for recurrent colorectal adenoma after screening colonoscopy with polypectomy