Root Growth of Arabidopsis thaliana Is Regulated by Ethylene and Abscisic Acid Signaling Interaction in Response to HrpNEa, a Bacterial Protein of Harpin Group

HrpN_Ea is a harpin protein from Erwinia amylovora, a bacterial pathogen that causes fire blight in rosaceous plants. Treating plants with HrpN_Ea stimulates ethylene and abscisic acid (ABA) to induce plant growth and drought tolerance, respectively. Herein, we report that both growth hormones cooperate to mediate the role of HrpN_Ea in promoting root growth of Arabidopsis thaliana seedlings. Root growth is promoted coordinately with elevation in levels of ABA and ethylene subsequent to soaking of germinating seeds of wild-type (WT) Arabidopsis in a solution of HrpN_Ea. However, these responses are arrested by inhibiting WT roots from synthesizing ethylene as well as sensing of ABA and ethylene. The effects of HrpN_Ea on roots are also nullified in ethylene-insensitive etr1-1 and ein5-1 mutants and in the ABA-insensitive mutant abi2-1 of Arabidopsis. These results provide evidence for presence of a relationship between root growth enhancement and signaling by ABA and ethylene in response to HrpN_Ea. Nevertheless, when HrpN_Ea is applied to leaves, ethylene signaling is active in the absence of ABA signaling to promote plant growth. This suggests the presence of a different signaling mechanism in leaves from that in roots. X. Ren and F. Liu contributed equally to this study and are regarded as joint first authors     

KPC1 expression and essential role after acute spinal cord injury in adult rat

KPC1 (Kip1 ubiquitylation-promoting complex 1) is the catalytic subunit of the ubiquitin ligase KPC, which regulates the degradation of the cyclin-dependent kinase inhibitor p27^kip1 at the G1 phase of the cell cycle. To elucidate the expression and role of KPC1 in nervous system lesion and repair, we performed an acute spinal cord contusion injury (SCI) model in adult rats. Western blot analysis showed a significant up-regulation of KPC1 and a concomitant down-regulation of p27^kip1 following spinal injury. Immunohistochemistry and immunofluorescence revealed wide expression of KPC1 in the spinal cord, including expression in neurons and astrocytes. After injury, KPC1 expression was increased predominantly in astrocytes, which highly expressed PCNA, a marker for proliferating cells. Co-immunoprecipitation demonstrated increased interactions between p27^kip1 and KPC1 4 days after injury. To understand whether KPC1 plays a role in astrocyte proliferation, we applied LPS to induce astrocyte proliferation in vitro. Western blot analysis demonstrated that p27^kip1 expression was negatively correlated with KPC1 expression following LPS stimulation. Immunofluorescence analysis showed subcellular localizations of p27^kip1 and KPC1 were also changed following the stimulation of astrocytes with LPS. These results suggest that KPC1 is related to the down-regulation of p27^kip1; this event may be involved in the proliferation of astrocytes after SCI.     

Determining a low disease activity threshold for decision to maintain disease-modifying antirheumatic drug treatment unchanged in rheumatoid arthritis patients

Introduction

The aim of this study was to determine a low disease activity threshold - a 28-joint disease activity score (DAS28) value - for the decision to maintain unchanged disease-modifying antirheumatic drug (DMARD) treatment in rheumatoid arthritis patients, based on expert opinion.

Methods

Nine hundred and sixty-seven case scenarios with various levels for each component of the DAS28 (resulting in a disease activity score between 2 and 3.2) were presented to 44 panelists. For each scenario, panelists had to decide whether or not DMARD treatment (excluding steroids) could be maintained unchanged. In each scenario, for decision, the participants were given the DAS28 parameters, without knowledge of the resultant DAS28. The relationship between panelists' decision, DAS28 value, and components of the score were analysed by multiple logistic regression analysis. Each panelist analysed 160 randomised scenarios. Intra-rater and inter-rater reproducibility were assessed.

Results

Forty-four panelists participated in the study. Inter-panelist agreement was good (κ = 0.63; 95% confidence interval = 0.61 to 0.65). Intra-panelist agreement was excellent (κ = 0.87; 95% confidence interval = 0.82 to 0.92). Quasi-perfect agreement was observed for DAS28 ≤ 2.4, less pronounced between 2.5 and 2.9, and almost no agreement for DAS28 > 3.0. For values below 2.5, panelists agreed to maintain unchanged DMARDs; for values above 2.5, discrepancies occurred more frequently as the DAS28 value increased. Multivariate analysis confirmed the relationship between panelist's decision, DAS28 value and components of the DAS28. Between DAS28 of 2.4 and 3.2, a major determinant for panelists' decision was swollen joint count. Female and public practice physicians decided more often to maintain treatment unchanged.

Conclusions

As a conclusion, panelists suggested that in clinical practice there is no need to change DMARD treatment in rheumatoid arthritis patients with DAS28 ≤ 2.4.     

Genome sequence of duck pathogen Mycoplasma anatis strain 1340

Mycoplasma anatis, a member of the class Mollicutes, is the causative agent of a contagious infectious disease of domestic ducklings, wild birds, and eggs. Increasing reports show that coinfection of M. anatis with Escherichia coli results in substantial economic impacts on the duck farms in China. Here, we announce the first genome sequence of M. anatis.     

Gender differences and effect of air pollution on asthma in children with and without allergic predisposition: northeast Chinese children health study

Background

Males and females exhibit different health responses to air pollution, but little is known about how exposure to air pollution affects juvenile respiratory health after analysis stratified by allergic predisposition. The aim of the present study was to assess the relationship between air pollutants and asthmatic symptoms in Chinese children selected from multiple sites in a heavily industrialized province of China, and investigate whether allergic predisposition modifies this relationship.

Methodology/Principal Findings

30139 Chinese children aged 3-to-12 years were selected from 25 districts of seven cities in northeast China in 2009. Information on respiratory health was obtained using a standard questionnaire from the American Thoracic Society. Routine air-pollution monitoring data was used for particles with an aerodynamic diameter ≤10 µm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO₂), ozone (O₃) and carbon monoxide (CO). A two-stage regression approach was applied in data analyses. The effect estimates were presented as odds ratios (ORs) per interquartile changes for PM₁₀, SO₂, NO₂, O₃, and CO. The results showed that children with allergic predisposition were more susceptible to air pollutants than children without allergic predisposition. Amongst children without an allergic predisposition, air pollution effects on asthma were stronger in males compared to females; Current asthma prevalence was related to PM₁₀ (ORs = 1.36 per 31 µg/m³; 95% CI, 1.08–1.72), SO₂ (ORs = 1.38 per 21 µg/m³; 95%CI, 1.12–1.69) only among males. However, among children with allergic predisposition, more positively associations between air pollutants and respiratory symptoms and diseases were detected in females; An increased prevalence of doctor-diagnosed asthma was significantly associated with SO₂ (ORs = 1.48 per 21 µg/m³; 95%CI, 1.21–1.80), NO₂ (ORs = 1.26 per 10 µg/m³; 95%CI, 1.01–1.56), and current asthma with O₃ (ORs = 1.55 per 23 µg/m³; 95%CI, 1.18–2.04) only among females.

Conclusion/Significance

Ambient air pollutions were more evident in males without an allergic predisposition and more associations were detected in females with allergic predisposition.     

Dynein,Lis1 and CLIP‐170 counteract Eg5‐dependent centrosome separation during bipolar spindle assembly

Bipolar spindle assembly critically depends on the microtubule plus‐end‐directed motor Eg5 that binds antiparallel microtubules and slides them in opposite directions. As such, Eg5 can produce the necessary outward force within the spindle that drives centrosome separation and inhibition of this antiparallel sliding activity results in the formation of monopolar spindles. Here, we show that upon depletion of the minus‐end‐directed motor dynein, or the dynein‐binding protein Lis1, bipolar spindles can form in human cells with substantially less Eg5 activity, suggesting that dynein and Lis1 produce an inward force that counteracts the Eg5‐dependent outward force. Interestingly, we also observe restoration of spindle bipolarity upon depletion of the microtubule plus‐end‐tracking protein CLIP‐170. This function of CLIP‐170 in spindle bipolarity seems to be mediated through its interaction with dynein, as loss of CLIP‐115, a highly homologous protein that lacks the dynein–dynactin interaction domain, does not restore spindle bipolarity. Taken together, these results suggest that complexes of dynein, Lis1 and CLIP‐170 crosslink and slide microtubules within the spindle, thereby producing an inward force that pulls centrosomes together.     

Characterization of the in vivo and in vitro metabolic profile of PAC-1 using liquid chromatography-mass spectrometry

In the present study, the metabolic profile of PAC-1, a potential anticancer drug, was investigated using liquid chromatography-mass spectrometric (LC/MS) techniques. Two different types of mass spectrometers--a quadrupole time-of-flight (Q-TOF) mass spectrometer and an ion trap (IT) mass spectrometer--were employed to acquire structural information on PAC-1 metabolites. A gradient liquid chromatographic system composed of 0.2% formic acid in methanol and 0.2% formic acid in water was used for metabolite separation on an Agilent TC-C(18) column. A total of 16 metabolites were detected. The corresponding product ion spectra were acquired and interpreted, and structures were proposed. Accurate mass measurement using LC-Q-TOF was used to determine the elemental composition of metabolites thereby confirming the proposed structures of these metabolites. Phase I metabolic changes were predominantly observed, including debenzylation, dihydrodiol formation, hydroxylation, and dihydroxylation. The detected phase II metabolites included PAC-1 and hydroxylated PAC-1 glucuronide conjugates. Based on metabolite analysis, several PAC-1 metabolic pathways in rat were proposed.     

Anti-adhesive Property of Maize Leaf Surface Related with Temperature and Humidity

The anti-adhesive surfaces have always aroused great interest of worldwide scientists and engineers.But in practical applications,it often faces the threat and impact of temperature and humidity.In this work,the excellent anti-adhesive performance of maize leaf under high temperature and humidity were investigated in detail.Firstly,the adhesion forces of the maize leaf surface under different temperature and humidity were measured by using Atomic Force Microscopy (AFM).The temperature of the substrate was varied between 23 ℃ to 100 ℃,and the ambient relative humidity is from 18％ to 100％.It was found that the adhesion force of maize leaf decreased with the increase of temperature and humidity.The mechanism of its excellent anti-adhesive performance of maize leaf under high temperature and relative humidity was revealed.The transverse and longitudinal ridges on maize leaf surface interlace with each other,forming small air pockets,which reduces the actual contact area between the object and the maize leaf.With the increase of humidity,the liquid film will be formed in the air pockets gradually and so much water vapor is produced with increase of temperature.Then the air flow rate increases though the wavy top of transverse ridges,inducing the dramatic decrease of adhesion force.Inspired by this mechanism,four samples with this bionic structure were made.This functional "biomimetic structure" would have potential value in the wide medical equipments such as high frequency electric knife with anti-adhesion surface under high temperature and high humidity.     

High‐Performance and Stable All‐Polymer Solar Cells Using Donor and Acceptor Polymers with Complementary Absorption

To explore the advantages of emerging all‐polymer solar cells (all‐PSCs), growing efforts have been devoted to developing matched donor and acceptor polymers to outperform fullerene‐based PSCs. In this work, a detailed characterization and comparison of all‐PSCs using a set of donor and acceptor polymers with both conventional and inverted device structures is performed. A simple method to quantify the actual composition and light harvesting contributions from the individual donor and acceptor is described. Detailed study on the exciton dissociation and charge recombination is carried out by a set of measurements to understand the photocurrent loss. It is unraveled that fine‐tuned crystallinity of the acceptor, matched donor and acceptor with complementary absorption and desired energy levels, and device architecture engineering can synergistically boost the performance of all‐PSCs. As expected, the PBDTTS‐FTAZ:PNDI‐T10 all‐PSC attains a high and stable power conversion efficiency of 6.9% without obvious efficiency decay in 60 d. This work demonstrates that PNDI‐T10 can be a potential alternative acceptor polymer to the widely used acceptor N2200 for high‐performance and stable all‐PSCs.