FJ, Liu Z, Tang W. Systematic profiling of alternative splicing events and splicing factors in left- and right-sided colon cancer

Left- and right-sided colon cancer (LC and RC) differ substantially in their molecular characteristics and prognoses, and are thus treated using different strategies. We systematically analyzed alternative splicing (AS) events and splicing factors in LC and RC. RNA-seq data were used for genome-wide profiling of AS events that could distinguish LC from RC. The Exon Skip splicing pattern was more common in RC, while the Retained Intron pattern was more common in LC. The AS events that were upregulated in RC were enriched for genes in the axon guidance pathway, while those that were upregulated in LC were enriched for genes in immune-related pathways. Prognostic models based on differentially expressed AS events were built, and a prognostic signature based on these AS events performed well for risk stratification in colon cancer patients. A correlation network of differentially expressed AS events and differentially expressed splicing factors was constructed, and RBM25 was identified as the hub gene in the network. In conclusion, large differences in AS events may contribute to the phenotypic differences between LC and RC. The differentially expressed AS events reported herein could be used as biomarkers and treatment targets for colon cancer.

A nomogram to predict vascular invasion before resection of colorectal cancer

Vascular invasion (VI) is an important feature for systemic recurrence and an indicator for the application of adjuvant therapy in colorectal cancer (CRC). Preoperative knowledge of VI is important in determining whether adjuvant therapy is necessary, as well as the adequacy of surgical resection. In the present study, a predictive nomogram for VI in patients with CRC was constructed. The prediction model consisted of 664 eligible patients with CRC, who were divided into a training set (n=468) and a validation set (n=196). Data were collected between August 2013 and April 2018. The feature selection model was established using the least absolute shrinkage and selection operator regression model. Multivariable logistic regression analysis was used to construct the predictive nomogram. The performance of the nomogram was evaluated by calibration, discrimination and clinical usefulness. Differentiation, computed tomography (CT)-based on N stage (CT N stage), hemameba and tumor distance from the anus (cm) were integrated into the nomogram. The nomogram exhibited good discrimination, with an area under the curve (AUC) of 0.731 and good calibration. Application of the nomogram in the validation cohort showed acceptable discrimination, with an AUC of 0.710 and good calibration. Decision curve analysis revealed that the nomogram was clinically useful. These findings suggests, to the best of our knowledge, that this may be the first nomogram for individual preoperative prediction of VI in patients with CRC, which may promote preoperative optimization strategies for this selected group of patients.

Fine-tuning the photosynthetic light harvesting apparatus for improved photosynthetic efficiency and biomass yield

Photosynthetic electron transport rates in higher plants and green algae are light-saturated at approximately one quarter of full sunlight intensity. This is due to the large optical cross section of plant light harvesting antenna complexes which capture photons at a rate nearly 10-fold faster than the rate-limiting step in electron transport. As a result, 75% of the light captured at full sunlight intensities is reradiated as heat or fluorescence. Previously, it has been demonstrated that reductions in the optical cross-section of the light-harvesting antenna can lead to substantial improvements in algal photosynthetic rates and biomass yield. By surveying a range of light harvesting antenna sizes achieved by reduction in chlorophyll b levels, we have determined that there is an optimal light-harvesting antenna size that results in the greatest whole plant photosynthetic performance. We also uncover a sharp transition point where further reductions or increases in antenna size reduce photosynthetic efficiency, tolerance to light stress, and impact thylakoid membrane architecture. Plants with optimized antenna sizes are shown to perform well not only in controlled greenhouse conditions, but also in the field achieving a 40% increase in biomass yield.

Decrease of FGF19 contributes to the increase of fasting glucose in human in an insulin-independent manner

PURPOSE

The ileum-derived fibroblast growth factor 19 (FGF19) plays key roles in hepatic glucose homeostasis in animals in an insulin-independent manner. Here, we analyzed the association of FGF19 with glucose effectiveness (GE, the insulin-independent glucose regulation), as well as hepatic glucose production (HGP) in Chinese subjects.

METHODS

GE was measured by frequently sampled intravenous glucose tolerance test (FSIVGTT) in normal glucose tolerance (NGT), isolated-impaired glucose tolerance (I-IGT), and isolated-impaired fasting glucose (I-IFG) subjects. The oral glucose tolerance test-derived surrogate of GE (oGE) was determined in NGT, I-IFG, combined glucose intolerance (CGI), and type 2 diabetes (T2DM) subjects. HGP was assessed by labeled ([3-³H]-glucose) hyperinsulinemic-euglycemic clamp in NGT subjects. Insulin secretion and sensitivity were calculated by the hyperglycemic and hyperinsulinemic-euglycemic clamps in a subgroup of NGT, I-IGT, and I-IFG subjects. Serum FGF19 levels were determined by ELISA.

RESULTS

FGF19 positively correlated with GE (r = 0.29, P = 0.004) as determined by FSIVGTT. The result was further confirmed by oGE (r = 0.261, P < 0.001). FGF19 was negatively associated with FPG (r = - 0.228, P = 0.025), but the association no longer existed after adjusting for GE (r = - 0.177, P = 0.086). FGF19 was negatively associated with basal HGP (r = - 0.697, P = 0.006). However, the correlation between FGF19 and insulin secretion and sensitivity were not found.

CONCLUSIONS

FGF19 levels are associated positively with GE and negatively with HGP. The increase of FPG in human is at least partially due to the decrease of FGF19 in an insulin-independent manner.

Relationship between neuronal network architecture and naming performance in temporal lobe epilepsy: A connectome based approach using machine learning

Impaired confrontation naming is a common symptom of temporal lobe epilepsy (TLE). The neurobiological mechanisms underlying this impairment are poorly understood but may indicate a structural disorganization of broadly distributed neuronal networks that support naming ability. Importantly, naming is frequently impaired in other neurological disorders and by contrasting the neuronal structures supporting naming in TLE with other diseases, it will become possible to elucidate the common systems supporting naming. We aimed to evaluate the neuronal networks that support naming in TLE by using a machine learning algorithm intended to predict naming performance in subjects with medication refractory TLE using only the structural brain connectome reconstructed from diffusion tensor imaging. A connectome-based prediction framework was developed using network properties from anatomically defined brain regions across the entire brain, which were used in a multi-task machine learning algorithm followed by support vector regression. Nodal eigenvector centrality, a measure of regional network integration, predicted approximately 60% of the variance in naming. The nodes with the highest regression weight were bilaterally distributed among perilimbic sub-networks involving mainly the medial and lateral temporal lobe regions. In the context of emerging evidence regarding the role of large structural networks that support language processing, our results suggest intact naming relies on the integration of sub-networks, as opposed to being dependent on isolated brain areas. In the case of TLE, these sub-networks may be disproportionately indicative naming processes that are dependent semantic integration from memory and lexical retrieval, as opposed to multi-modal perception or motor speech production.

Fast genome editing in Bacillus subtilis

Bacillus subtilis is a model organism for Gram-positive bacteria and widely used in the study of cellular functions and processes including protein secretion, sporulation, and signal transduction. It is also an important industrial host for the production of proteins and chemicals. Generally, genome editing of B. subtilis often needs the construction of integration vectors in Escherichia coli, linearizing the constructed plasmids, and subsequent transformation of the linear deoxyribonucleic acid via natural competence or electroporation. In this work, we examined the feasibility to directly transform and integrate B. subtilis using linear deoxyribonucleic acid from Gibson assembly without the need for cloning in E. coli. Linear deoxyribonucleic acid of 8-10 kb showed the highest transformation efficiency which was similar to that of using linearized plasmids constructed in E. coli. This method shortens the overall process from 1 week to 1 day and allows the integration of multiple genes in one step, providing a simple and fast method for genome editing in B. subtilis.

Development and Validation of a Nomogram for Preoperative Prediction of Perineural Invasion in Colorectal Cancer

Background

In colorectal cancer (CRC), perineural invasion (PNI) is usually identified histologically in biopsy or resection specimens and is considered a high-risk feature for recurrence of CRC and is an indicator for adjuvant therapy. Preoperative identification of PNI could help determine the need for adjuvant therapy and the approach to surgical resection. This study aimed to develop and validate a nomogram for the preoperative prediction of PNI in patients with CRC.

Material/Methods

A total of 664 patients with CRC from a single center were classified into a training dataset (n=468) and a validation dataset (n=196). The least absolute shrinkage and selection operator (LASSO) regression model was used to select potentially relevant features. Multivariate logistic regression analysis was used to develop the nomogram. The performance of the nomogram was assessed based on its calibration, discrimination, and clinical utility.

Results

The nomogram consisted of five clinical features and provided good calibration and discrimination in the training dataset, with an area under the curve (AUC) of 0.704 (95% CI, 0.657–0.751). Application of the nomogram in the validation cohort showed acceptable discrimination, with the AUC of 0.692 (95% CI, 0.617–0.766) and good calibration. Decision curve analysis (DCA) showed that the nomogram was clinically useful.

Conclusions

The nomogram developed in this study might allow clinicians to predict the risk of PNI in patients with CRC preoperatively. The nomogram showed favorable discrimination and calibration values, which may help optimize preoperative treatment decision-making for patients with CRC.

FDG-PET and MRI in the Evolution of New-Onset Refractory Status Epilepticus

BACKGROUND AND PURPOSE

New-onset refractory status epilepticus is a clinical condition characterized by acute and prolonged pharmacoresistant seizures without a pre-existing relevant neurologic disorder, prior epilepsy, or clear structural, toxic, or metabolic cause. New-onset refractory status epilepticus is often associated with antineuronal antibodies and may respond to early immunosuppressive therapy, reflecting an inflammatory element of the condition. FDG-PET is a useful diagnostic tool in inflammatory and noninflammatory encephalitis. We report here FDG-PET findings in new-onset refractory status epilepticus and their correlation to disease activity, other imaging findings, and outcomes.

MATERIALS AND METHODS

Twelve patients who met the criteria for new-onset refractory status epilepticus and who had FDG-PET and MR imaging scans and electroencephalography at a single academic medical center between 2008 and 2017 were retrospectively identified. Images were independently reviewed by 2 radiologists specialized in nuclear imaging. Clinical characteristics and outcome measures were collected through chart review.

RESULTS

Twelve patients underwent 21 FDG-PET scans and 50 MR imaging scans. Nine (75%) patients were positive for autoantibodies. All patients had identifiable abnormalities on the initial FDG-PET in the form of hypermetabolism (83%) and/or hypometabolism (42%). Eight (67%) had medial temporal involvement. All patients (n = 3) with N-methyl-D-aspartic acid receptor antibodies had profound bilateral occipital hypometabolism. Initial MR imaging findings were normal in 6 (50%) patients. Most patients had some degree of persistent hyper- (73%) or hypometabolism (45%) after immunosuppressive therapy. FDG-PET hypometabolism was predictive of poor outcome (mRS 4-6) at hospital discharge (P = .028).

CONCLUSIONS

Both FDG-PET hypometabolism and hypermetabolism are seen in the setting of new-onset refractory status epilepticus and may represent markers of disease activity.

Treatment Response Prediction of Nasopharyngeal Carcinoma Based on Histogram Analysis of Diffusional Kurtosis Imaging

BACKGROUND AND PURPOSE

The prediction of treatment response is important in planning and modifying the chemoradiation therapy regimen. This study aimed to explore the quantitative histogram indices for treatment-response prediction of nasopharyngeal carcinoma based on diffusional kurtosis imaging compared with a standard ADC value (ADC_standard).

MATERIALS AND METHODS

Thirty-six patients with an initial diagnosis of locoregionally advanced nasopharyngeal carcinoma and diffusional kurtosis imaging acquisitions before and after neoadjuvant chemotherapy were enrolled. Patients were divided into respond-versus-nonrespond groups after neoadjuvant chemotherapy and residual-versus-nonresidual groups after radiation therapy. Histogram parameters of diffusional kurtosis imaging-derived parameters (ADC, ADC coefficient corrected by the non-Gaussain model [D], apparent kurtosis coefficient without a unit [K]) were calculated. The ADC_standard was calculated on the basis of intravoxel incoherent movement data. The intraclass correlation coefficient, Kolmogorov-Smirnov test, Student t test or Mann-Whitney U test, and receiver operating characteristic analysis were performed.

RESULTS

Most of the parameters had good-to-excellent consistency (intraclass correlation coefficient = 0.675-0.998). The pre-ADC_standard, pre-ADC (10th, 25th, 50th percentiles), pre-D (10th, 25th, 50th percentiles), and pre-K_50th were significantly different between the respond and nonrespond groups, while the pre-ADC_10th, pre-K_90th, post-ADC_50th, post-K_75th, post-K_90th, and the percentage change of parameters before and after neoadjuvant chemotherapy (▵ADC_50th%) were significantly different between the residual and nonresidual groups (all P < .05). Receiver operating characteristic analysis indicated that setting pre-D_50th = 0.875 × 10^-3mm²/s as the cutoff value could result in optimal diagnostic performance for neoadjuvant chemotherapy response prediction (area under the curve = 0.814, sensitivity = 0.70, specificity = 0.92), while the post-K_90th = 1.035 (area under the curve = 0.829, sensitivity = 0.78, specificity = 0.72), and▵ADC_50th% = 0.253 (area under the curve = 0.833, sensitivity = 0.94, specificity = 0.72) were optimal for radiation therapy response prediction.

CONCLUSIONS

Histogram analysis of diffusional kurtosis imaging may potentially predict the neoadjuvant chemotherapy and short-term radiation therapy response in locoregionally advanced nasopharyngeal carcinoma, therefore providing evidence for modification of the treatment regimen.

Population genetic analyses of seven Chinese indigenous chicken breeds in a context of global breeds

Jiangxi province in China is rich in indigenous chicken breeds, which have diverse phenotypes and represent a valuable genetic resource for further genetic improvement of modern breeds. Here, we conducted a series of analyses to reveal genetic diversity, phylogenetic relationships and population structure of seven chicken breeds in Jiangxi province in the context of nine non-local chicken breeds, using 600K SNP data. We show that Jiangxi indigenous breeds have more abundant nucleotide diversity than do European local and commercial breeds. Among Jiangxi breeds, Dongxiang Blue-eggshell (DX) and Chongren Partride (CR) display remarkably reduced genetic diversity, as the two breeds exhibit increased inbreeding coefficients, runs of homozygosity, extent of linkage disequilibrium and reduced expected heterozygosity. DX, CR and Taihe Silkie (TH) represent three ancestral lineages of the Jiangxi chicken and display genetic differentiation from the other four Jiangxi breeds, which show a signature of admixture with European commercial breeds. These findings provide insight for the establishment of an efficient conservation program for Jiangxi chicken breeds. Considering the current status of genetic diversity and ancestral representativeness, particular attention should be paid to DX, CR and TH chickens.

[Clinical outcomes of gastric cancer patients received capecitabine based adjuvant chemotherapy and the corresponding pharmacogenomics analysis]

Objective: To investigate the association between Thymidine phosphorylase(TYMP)genetic variation and clinical outcomes of postoperative gastric cancer (GC) patients received capecitabine based regimens. Methods: A total of 198 GC patients underwent surgical treatment and received capecitabine based adjuvant chemotherapy were included in this retrospective study. Peripheral blood and the postoperative tissue specimen of the GC patients were collected for the genotyping of polymorphism and TYMP mRNA expression, respectively. The correlation between polymorphism and clinical outcomes and safety of postoperative GC patients were analysed. Results: Located in the upstream, rs11479 was of clinical significance. The prevalence of rs11479 in TYMP among the GC patients were as follows: CC genotype 125 cases (63.13%), CT genotype 65 cases (32.83%), TT genotype 8 cases (4.04%), minor allele frequency of rs11479 is 0.20. The distribution of three genotypes were in accordance with Hardy-Weinberg Equilibrium (P=0.901). The analysis results of patients with different genotypes found that the 3-year disease free survival rate of the patients with CT/TT genotype and CC genotype were 73.97% and 65.60%, respectively, which was statistically significant (P=0.003). In terms of overall survival, the 3-year overall survival rate of the two genotypes were 83.56% and 72.80% (P=0.012), respectively. Adjusted in multivariate Cox regression analysis, CT/TT genotype was an independent favorable factor for disease free survival (OR=0.55, P=0.011). Safety analysis indicated that there was no significant association between genotypes and grade 2 adverse reaction. Additionally, of the 79 postoperative tissue specimens, the results showed that the expression of TYMP in cancer tissues of the patients with CT/TT genotypes were significantly higher than those of the wild type CC genotype patients (P<0.001). Conclusion: The polymorphism rs11479 of TYMP have favorable influence on the clinical outcomes of gastric cancer patients received capecitabine based adjuvant chemotherapy treatment through changing the mRNA expression of TYMP.

α-Expansin EXPA4 Positively Regulates Abiotic Stress Tolerance but Negatively Regulates Pathogen Resistance in Nicotiana tabacum

Since they function as cell wall-loosening proteins, expansins can affect plant growth, developmental processes and environmental stress responses. Our previous study demonstrated that changes in Nicotiana tabacum α-expansin 4 (EXPA4) expression affect the sensitivity of tobacco to Tobacco mosaic virus [recombinant TMV encoding green fluorescent protein (TMV-GFP)] infection by Agrobacterium-mediated transient expression. In this study, to characterize the function of tobacco EXPA4 further, EXPA4 RNA interfernce (RNAi) mutants and overexpression lines were generated and assayed for their tolerance to abiotic stress and resistance to pathogens. First, the differential phenotypes and histomorphology of transgenic plants with altered EXPA4 expression indicated that EXPA4 is essential for normal tobacco growth and development. By utilizing tobacco EXPA4 mutants with abiotic stress, it was demonstrated that RNAi mutants have increased hypersensitivity to salt and drought stress. In contrast, the overexpression of EXPA4 in tobacco conferred greater tolerance to salt and drought stress, as indicated by less cell damage, higher fresh weight, higher soluble sugar and proline accumulation, and higher expression levels of several stress-responsive genes. In addition, the overexpression lines were more susceptible to the viral pathogen TMV-GFP when compared with the wild type or RNAi mutants. The induction of the antioxidant system, several defense-associated phytohormones and gene expression was down-regulated in overexpression lines but up-regulated in RNAi mutants when compared with the wild type following TMV-GFP infection. In addition, EXPA4 overexpression also accelerated the disease development of Pseudomonas syringae DC3000 on tobacco. Taken together, these results suggested that EXPA4 appears to be important in tobacco growth and responses to abiotic and biotic stress.

T2 mapping in dermatomyositis/polymyositis and correlation with clinical parameters

AIM

To explore the T2-mapping signal characteristics of the thigh muscles in patients with dermatomyositis/polymyositis (DM/PM) and to investigate the correlation between thigh muscle T2 values, clinical parameters, and serum creatinine kinase (CK).

MATERIALS AND METHODS

Forty-two patients with DM/PM proven by diagnostic criteria were enrolled in the study along with 13 healthy control subjects. Both T2-mapping and conventional magnetic resonance imaging (MRI) images were obtained in the thigh musculature of all subjects. The T2 values of thigh muscles were compared between the DM/PM patients and control groups. Thirty-one DM/PM patients were evaluated with manual muscle testing (MMT) and serum CK levels. A Spearman correlation coefficient model was used to correlate the mean T2 values and clinical assessments. The Kruskal-Wallis test and receiver operating characteristic (ROC) curves were also utilised. p-Values <0.05 reflected statistical significance.

RESULTS

The T2 value of all oedematous muscles was greater on average than that of the unaffected muscles of the DM/PM patients (p<0.05) and the muscles of healthy volunteers (p<0.05). The T2 value of unaffected muscles in DM/PM patients was also greater than that of the normal muscles in healthy volunteers (p<0.05). The area under the curves (AUCs) for T2 relaxation time values was 0.72 with respective sensitivity and specificity of 72.6% and 65.4%. The mean T2 relaxation time of the 31 patients group and the MMTs (p<0.05) was correlated without serum CK levels (p>0.05).

CONCLUSION

T2 mapping is not only quantitatively used for subclinical muscle involvement in DM/PM, but also be used to demonstrate severity of damaged muscles in DM/PM.

The immunosuppressive effects of CD4+ CD25+ regulatory T cells on dendritic cells in patients with chronic hepatitis B

The characteristics and functions of CD4⁺ CD25⁺ regulatory T cells (Tregs) have been well defined in murine and human systems. However, the interaction or crosstalk between CD4⁺ CD25⁺ Tregs and dendritic cells (DCs) remains controversial. In this study, the effects of chronic hepatitis B (CHB) CD4⁺ CD25⁺ Tregs on the maturation and function of monocyte-derived DCs were examined. The results showed that CD4⁺ CD25⁺ render the DCs inefficient as antigen-presenting cells (APCs) despite prestimulation with CD40 ligand. This effect was marginally reverted by applying neutralizing antibodies (Abs) to IL-10 and TGF-β. There were an increased IL-10 and TGF-β secretion and reduced expression of costimulatory molecules in DC. Thus, in addition to a direct suppressor effect on CD4⁺ T cells, CD4⁺ CD25⁺ may modulate the immune response through DCs in CHB patients.

Cell geometry across the ring structure of Sitka spruce

For wood to be used to its full potential as an engineering material, it is necessary to quantify links between its cell geometry and the properties it exhibits at bulk scale. Doing so will make it possible to predict timber properties crucial to engineering, such as mechanical strength and stiffness, and the resistance to fluid flow, and to inform strategies to improve those properties as required, as well as to measure the effects of interventions such as genetic manipulation and chemical modification. Strength, stiffness and permeability of timber all derive from the geometry of its cells, and yet current practice is to predict them based on properties, such as bulk density, that do not directly describe the cell structure. This work explores links between micro-computed tomography data for structural-size pieces of wood, which show the variation of porosity across the wood's ring structure, and high-resolution tomography showing the geometry of the cells, from which we measure cell length, lumen area, porosity, cell wall thickness and the number density of cells. High-resolution scans, while informative, are time-consuming and expensive to run on a large number of samples at the scale of building components. By scanning the same volume of timber at both low and high resolutions (high-resolution scans over a near-continuous volume of timber of approx. 20 mm3 at 15 μm3 per voxel), we are able to demonstrate correlations between the measurements at the two different resolutions, reveal the physical basis for these correlations, and demonstrate that the data from the low-resolution scan can be used to estimate the variation in (small-scale) cell geometry throughout a structural-size piece of wood.

The use of Dual Lumen Jugular Venous Catheters as Definitive Long Term Access for Haemodialysis

We describe the long term use for haemodialysis of the PermCath (Quinton, Seattle, Washington) dual lumen, jugular venous catheter (DLJVC) in 21 patients who had no apparent alternative means of access. The nineteen patients maintained in this manner for periods of 30 to 600 days (mean 233.2) included 6 patients dialyzed for over 12 months. Blood flows exceeded 250 mls/min and recirculation rates averaged 5.9%. Infection and insufficiency due to thrombosis were the major problems. In 8 patients (38.1%) infection required DLJVC removal; in three the catheter was immediately replaced over a guidewire along the same track under antibiotic cover and infection has not recurred. Insufficiency occurred in 10 patients (47.6%) and was successfully managed with oral anticoagulants, local instillation of urokinase (4 cases), systemic streptokinase (2 cases) or by changing the DLJVC over a guidewire (2 cases). We believe that the DLJVC is the long term access method of choice for patients in whom conventional access cannot be constructed.

Identification and characterization of ace1-type acetylcholinesterase in insecticide-resistant and -susceptible Propylaea japonica (Thunberg)

Characterization and gene cloning of acetylecholinesterase (AChE) in the insecticide-resistant (R) and -susceptible (S) insects have been reported in the past. However, the studies focused mostly on herbivorous pests, rather than predacious species, such as ladybird beetles. Using R and S Propylaea japonica (thunberg), a full-length cDNA sequence (2928 bp) of the ace1-type AChE gene was determined for the first time. The ace1 encoding a protein of 645 amino acids contained typical conserved motifs, such as FGESAG domains, catalytic triad, acyl pocket, oxyanino hole, choline binding site, peripheral anionic site, omega loop and conserved aromatic residues. R P. japonica displayed 50-times greater resistance to chlorpyrifos or mathamidophos with a significantly lower AChE sensitivity to paraoxon, malaoxon, chlorpyrifos or methamidophos than its S counterpart. Five amino acids in the ace1 of R P. japonica differed from those found in S P. japonica. One of them, F358S, located in the acyl-binding pocket, might play a crucial role in the resistance of the insect to organophosphates (OPs). Whereas, K493E and I538V, which were close to some of the conserved aromatic amino acids (i.e., H509, Y511, and W499) in the gorge, and G571R and T576A near C593 that formed the disulfide bonds with C471, might also involve in the change of insecticide resistance in P. japonica. AChE insensitivity and amino acid replacements, particularly F358S, might be the determining factors in the alteration of OPs-resistance in P. japonica.

Evidence for negative thermal expansion in the superconducting precursor phase SmFeAsO

The fluorine-doped rare-earth iron oxypnictide series SmFeAsO1-x F x (0 [Formula: see text] 0.10) was investigated with high resolution powder x-ray scattering. In agreement with previous studies (Margadonna et al 2009 Phys. Rev. B. 79 014503), the parent compound SmFeAsO exhibits a tetragonal-to-orthorhombic structural distortion at [Formula: see text]  =  130 K which is rapidly suppressed by [Formula: see text] 0.10 deep within the superconducting dome. The change in unit cell symmetry is followed by a previously unreported magnetoelastic distortion at 120 K. The temperature dependence of the thermal expansion coefficient [Formula: see text] reveals a rich phase diagram for SmFeAsO: (i) a global minimum at 125 K corresponds to the opening of a spin-density wave instability as measured by pump-probe femtosecond spectroscopy (Mertelj et al 2010 Phys. Rev. B 81 224504) whilst (ii) a global maximum at 110 K corresponds to magnetic ordering of the Sm and Fe sublattices as measured by magnetic x-ray scattering (Nandi et al 2011 Phys. Rev. B 84 055419). At much lower temperatures than [Formula: see text], SmFeAsO exhibits a significant negative thermal expansion on the order of  -40 ppm · K-1 in contrast to the behaviour of other rare-earth oxypnictides such as PrFeAsO (Kimber et al 2008 Phys. Rev. B 78 140503) and the actinide oxypnictide NpFeAsO (Klimczuk et al 2012 Phys. Rev. B 85 174506) where the onset of [Formula: see text] 0 only appears in the vicinity of magnetic ordering. Correlating this feature with the temperature and doping dependence of the resistivity and the unit cell parameters, we interpret the negative thermal expansion as being indicative of the possible condensation of itinerant electrons accompanying the opening of a SDW gap, consistent with transport measurements (Tropeano et al 2009 Supercond. Sci. Technol. 22 034004).

MultiLink – An Intermediary System for Multi-Database Access

The design and implementation is described of MultiLink, a desktop system for direct enduser access to remote bibliographic information. The system is an application of a client-server technique based on a campuswide network, with the objective to assist end-users to accomplish the information — retrieval process by capturing knowledge and expertise for searches in query formulations. MultiLink, via intelligent interfaces, allows users to access several dozens of bibliographic databases. The application integrates regional, national and international resources, and brings library services to the user’s desktop level.

Tobacco alpha-expansin EXPA4 plays a role in Nicotiana benthamiana defence against Tobacco mosaic virus

MAIN CONCLUSION

Tobacco EXPA4 plays a role in Nicotiana benthamiana defence against virus attack and affects antioxidative metabolism and phytohormone-mediated immunity responses in tobacco. Expansins are cell wall-loosening proteins known for their endogenous functions in cell wall extensibility during plant growth. The effects of expansins on plant growth, developmental processes and environment stress responses have been well studied. However, the exploration of expansins in plant virus resistance is rarely reported. In the present study, virus-induced gene silencing (VIGS) and Agrobacterium-mediated transient overexpression were conducted to investigate the role of Nicotiana tabacum alpha-expansin 4 (EXPA4) in modulating Tobacco mosaic virus (TMV-GFP) resistance in Nicotiana benthamiana. The results indicated that silencing of EXPA4 reduced the sensitivity of N. benthamiana to TMV-GFP, and EXPA4 overexpression accelerated virus reproduction on tobacco. In addition, our data suggested that the changes of virus accumulation in response to EXPA4 expression levels could further affect the antioxidative metabolism and phytohormone-related pathways in tobacco induced by virus inoculation. EXPA4-silenced plants with TMV-GFP have enhanced antioxidant enzymes activities, which were down-regulated in virus-inoculated 35S:EXPA4 plants. Salicylic acid accumulation and SA-mediated defence genes induced by TMV-GFP were up-regulated in EXPA4-silenced plants, but depressed in 35S:EXPA4 plants. Furthermore, a VIGS approach was used in combination with exogenous phytohormone treatments, suggesting that EXPA4 has different responses to different phytohormones. Taken together, these results suggested that EXPA4 plays a role in tobacco defence against viral pathogens.