Laccase is necessary and nonredundant with peroxidase for lignin polymerization during vascular development in Arabidopsis

The evolution of lignin biosynthesis was critical in the transition of plants from an aquatic to an upright terrestrial lifestyle. Lignin is assembled by oxidative polymerization of two major monomers, coniferyl alcohol and sinapyl alcohol. Although two recently discovered laccases, LAC4 and LAC17, have been shown to play a role in lignin polymerization in Arabidopsis thaliana, disruption of both genes only leads to a relatively small change in lignin content and only under continuous illumination. Simultaneous disruption of LAC11 along with LAC4 and LAC17 causes severe plant growth arrest, narrower root diameter, indehiscent anthers, and vascular development arrest with lack of lignification. Genome-wide transcript analysis revealed that all the putative lignin peroxidase genes are expressed at normal levels or even higher in the laccase triple mutant, suggesting that lignin laccase activity is necessary and nonredundant with peroxidase activity for monolignol polymerization during plant vascular development. Interestingly, even though lignin deposition in roots is almost completely abolished in the lac11 lac4 lac17 triple mutant, the Casparian strip, which is lignified through the activity of peroxidase, is still functional. Phylogenetic analysis revealed that lignin laccase genes have no orthologs in lower plant species, suggesting that the monolignol laccase genes diverged after the evolution of seed plants.

Different APC genotypes in proximal and distal sporadic colorectal cancers suggest distinct WNT/β-catenin signalling thresholds for tumourigenesis

Biallelic protein-truncating mutations in the adenomatous polyposis coli (APC) gene are prevalent in sporadic colorectal cancer (CRC). Mutations may not be fully inactivating, instead producing WNT/β-catenin signalling levels 'just-right' for tumourigenesis. However, the spectrum of optimal APC genotypes accounting for both hits, and the influence of clinicopathological features on genotype selection remain undefined. We analysed 630 sporadic CRCs for APC mutations and loss of heterozygosity (LOH) using sequencing and single-nucleotide polymorphism microarrays, respectively. Truncating APC mutations and/or LOH were detected in 75% of CRCs. Most truncating mutations occurred within a mutation cluster region (MCR; codons 1282-1581) leaving 1-3 intact 20 amino-acid repeats (20AARs) and abolishing all Ser-Ala-Met-Pro (SAMP) repeats. Cancers commonly had one MCR mutation plus either LOH or another mutation 5' to the MCR. LOH was associated with mutations leaving 1 intact 20AAR. MCR mutations leaving 1 vs 2-3 intact 20AARs were associated with 5' mutations disrupting or leaving intact the armadillo-repeat domain, respectively. Cancers with three hits had an over-representation of mutations upstream of codon 184, in the alternatively spliced region of exon 9, and 3' to the MCR. Microsatellite unstable cancers showed hyper-mutation at MCR mono- and di-nucleotide repeats, leaving 2-3 intact 20AARs. Proximal and distal cancers exhibited different preferred APC genotypes, leaving a total of 2 or 3 and 0 to 2 intact 20AARs, respectively. In conclusion, APC genotypes in sporadic CRCs demonstrate 'fine-tuned' interdependence of hits by type and location, consistent with selection for particular residual levels of WNT/β-catenin signalling, with different 'optimal' thresholds for proximal and distal cancers.

Metabolic engineering of the phenylpropanoid pathway enhances the antioxidant capacity of Saussurea involucrata

The rare wild species of snow lotus Saussurea involucrata is a commonly used medicinal herb with great pharmacological value for human health, resulting from its uniquely high level of phenylpropanoid compound production. To gain information on the phenylpropanid biosynthetic pathway genes in this critically important medicinal plant, global transcriptome sequencing was performed. It revealed that the phenylpropanoid pathway genes were well represented in S. involucrata. In addition, we introduced two key phenylpropanoid pathway inducing transcription factors (PAP1 and Lc) into this medicinal plant. Transgenic S. involucrata co-expressing PAP1 and Lc exhibited purple pigments due to a massive accumulation of anthocyanins. The over-expression of PAP1 and Lc largely activated most of the phenylpropanoid pathway genes, and increased accumulation of several phenylpropanoid compounds significantly, including chlorogenic acid, syringin, cyanrine and rutin. Both ABTS (2,2′-azinobis-3-ethylbenzotiazo-line-6-sulfonic acid) and FRAP (ferric reducing anti-oxidant power) assays revealed that the antioxidant capacity of transgenic S. involucrata lines was greatly enhanced over controls. In addition to providing a deeper understanding of the molecular basis of phenylpropanoid metabolism, our results potentially enable an alternation of bioactive compound production in S. involucrata through metabolic engineering.

Evaluation of a New 1H/31P Dual-Tuned Birdcage Coil for 31P Spectroscopy

We introduce a new dual-tuned Hydrogen/Phosphorus (¹H/³¹P) birdcage coil, referred to as split birdcage coil, and evaluate its performance using both simulations and magnetic resonance (MR) experiments on a 3 T MR scanner. The proposed coil simplifies the practical matters of tuning and matching, which makes the coil easily reproducible. Simulations were run with the Finite Difference in Time Domain (FDTD) method to evaluate the sensitivity and homogeneity of the magnetic field generated by the proposed ¹H coils. Following simulations, MR experiments were conducted using both a phantom and human thigh to compare the proposed design with a currently available commercial dual-tuned flexible surface coil, referred to as flex surface coil, for signal to noise ratio (SNR) as well as homogeneity for the ³¹P coil. At regions deep within the human thigh, the split birdcage coil was able to acquire spectroscopic signal with a higher average SNR than the flex surface coil. For all regions except those close to the flex surface coil, the split birdcage coil matched or exceeded the performance of the flex surface coil.

Relation of excess body weight and survival in patients with esophageal adenocarcinoma: a meta-analysis

Excess body weight (body mass index >25 kg/m(2)) is common in patients with esophageal adenocarcinoma. In this study, a meta-analysis was performed by searching PubMed, Cochrane Library, EMBASE, and Science Direct databases from 1960 to June 2012. Data were extracted from studies comparing survival in obese (body mass index >30), overweight (body mass index 25-29), and normal-weight (body mass index 20-24) patients undergoing esophagectomy. A total of six studies with 1988 cases were suitable for this global meta-analysis. Compared with patients of normal weight, the hazard ratio of postoperational survival for overweight and obese patients was 0.79 (95% confidence interval 0.65-0.95, P = 0.108) and 0.80 (95% confidence interval 0.68-0.93, P = 1.00), respectably. Taken together, the excess body weight did not have the value of predicting survival for patients with esophageal adenocarcinoma.

A nosocomial outbreak of KPC-2-producing Klebsiella pneumoniae in a Chinese hospital: dissemination of ST11 and emergence of ST37, ST392 and ST395

In China, Klebsiella pneumoniae carbapenemase (KPC) -producing K. pneumoniae isolates have been identified. However, little is known about the spread and outbreak of KPC-producing enterobacterial pathogens. In this study, 48 non-duplicated KPC-producing isolates were analysed for genetic relatedness by pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility by E-test, and sequence type (ST) by multilocus sequence typing. S1-PFGE and Southern blot were used for plasmid profiling, and PCR and subsequent sequencing were performed to determine the effects of genetic background on the blaKPC gene. From December 2011 to June 2012, an outbreak of the KPC-2-producing K. pneumoniae was observed. The 48 isolates of K. pneumoniae are categorized into eight PFGE types (A1, A2, A3, A4, B, C, D and E). The predominant pathogens of the outbreak were strains with PFGE types A1, A2 and A3, which all belong to ST11. Furthermore, ST37, ST392 and ST395 KPC-2-producing K. pneumoniae isolates have also been sporadically identified. The blaKPC-2 -carrying plasmids vary in size from 30 to 220 kb. The genetic environments of the blaKPC-2 gene for most strains were consistent with the genetic structure of blaKPC-2 on the plasmid pKP048. In conclusion, the dissemination and outbreak of KPC-2-producing K. pneumoniae isolates in this study appeared to be clonal, and ST11 K. pneumoniae was the predominant clone attributed to the outbreak. This is the first study to report the emergence and spread of KPC-producing K. pneumoniae ST392 and ST395 worldwide. Our findings suggest that horizontal transfer of Tn3-based transposons might mediate the spread of blaKPC-2 gene between different K. pneumoniae clones in China.

Observation of a charged charmoniumlike structure in e+ e- → π+ π- J/ψ at sqrt[s] = 4.26 GeV

We study the process ee+ e- → π+ π- J/ψ at a center-of-mass energy of 4.260 GeV using a 525  pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross section is measured to be (62.9±1.9±3.7)  pb, consistent with the production of the Y(4260). We observe a structure at around 3.9  GeV/c2 in the π(±)J/ψ mass spectrum, which we refer to as the Z(c)(3900). If interpreted as a new particle, it is unusual in that it carries an electric charge and couples to charmonium. A fit to the π(±)J/ψ invariant mass spectrum, neglecting interference, results in a mass of (3899.0±3.6±4.9)  MeV/c2 and a width of (46±10±20)  MeV. Its production ratio is measured to be R = (σ(e+ e- → π(±)Z(c)(3900)(∓) → π+ π- J/ψ)/σ(e+ e- → π+ π- J/ψ)) = (21.5±3.3±7.5)%. In all measurements the first errors are statistical and the second are systematic.

Severe brain damage in premature infants associated with postnatal infection

AIM

This study examined clinical features and neuroimaging characteristics of severe brain damage in premature infants with postnatal infection.

METHODS

We retrospectively analyzed clinical data of two preterm infants who developed extensive encephalomalacia secondary to postnatal infection.

RESULTS

Two premature boys experienced serious postnatal infection at about 3 weeks after birth; the infection was characterized by lethargy, apnea, increased CRP, severe bilateral pneumonia, positive sputum culture for multidrug-resistant bacteria, and mild changes of cerebrospinal fluid. Both infants required ventilation and antibiotic therapy. While both infants survived, a very extensive encephalomalacia was documented by serial cranial ultrasound, MRI and CT scans 3 to 4 weeks after postnatal infection. Their mothers had no premature ruptures of membranes and no signs of antenatal infection, suggesting potential postnatal infection in the infants.

CONCLUSION

More studies are needed to better understand the underlying mechanism of encephalomalacia associated with postnatal infection. To facilitate early diagnosis and effective treatment, cranial ultrasound scans should be done routinely in premature infants with serious postnatal infection.

DNA methylation patterns of peroxisome proliferator-activated receptor gamma gene associated with liver fibrosis and inflammation in chronic hepatitis B

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that regulates gene expression of inflammatory mediators in liver injury. Hepatitis B virus (HBV) suppresses the PPAR gamma-mediated transactivation in liver cancerous cell lines. However, the role of PPAR gamma in patients with chronic HBV infection has not fully demonstrated. Our present study was firstly to determine the clinical relevance of peripheral PPAR gamma mRNA levels in chronic hepatitis B (CHB) patients, and then, the DNA methylation of PPAR gamma promoter was investigated. Peripheral blood mononuclear cells (PBMCs) were isolated from 91 CHB patients and 18 healthy controls. The mRNA level of PPAR gamma was determined by quantitative real-time PCR; meanwhile, the CpG island methylation was assessed by methylation-specific PCR. CHB patients showed significantly lower mRNA level of PPAR gamma than healthy controls (P = 0.005). The mRNA level was decreased in HBV-DNA-positive group than HBV-DNA-negative group (P = 0.041). Interaction analysis demonstrated that the DNA methylation pattern was responsible for the suppression of peripheral PPAR gamma transcription in CHB patients (P = 0.003). Furthermore, the hypermethylation of PPAR gamma gene promoter was significantly associated with liver inflammation and fibrosis in CHB. In conclusion, DNA methylation patterns were responsible for the decreased mRNA level of peripheral PPAR gamma in CHB patients. Liver inflammation and fibrosis were found to be associated with hypermethylation of PPAR gamma promoter.

Seroprevalence of Chlamydia psittaci infection in market-sold adult chickens, ducks and pigeons in north-western China

Chlamydia psittaci, the agent of psittacosis in humans, infects a wide range of avian species. To assess the risk of psittacosis posed by domestic birds in the urban environment, the prevalence of C. psittaci antibodies in 413 chickens (Gallus domesticus; 305 caged and 108 free-range), 334 ducks (Anas spp.; 111 caged and 223 free-range) and 312 pigeons (Columba livia) in Lanzhou, north-western China, was detected using the indirect haemagglutination assay. The specific antibodies were found in sera of 55 (13.32 %) chickens, 130 (38.92 %) ducks and 97 (31.09 %) pigeons. Statistical analysis showed that the seroprevalence of C. psittaci infection in chickens was significantly lower than that in ducks and pigeons (P<0.05). The C. psittaci seroprevalence in caged and free-range chickens was 7.54 % and 29.63 %, respectively, and the difference was statistically significant (P<0.05). The C. psittaci seroprevalence in caged and free-range ducks was 26.13 % and 45.29 %, respectively (P<0.05). To our knowledge, this is the first study indicating the presence of C. psittaci infection in market-sold chickens, ducks and pigeons in north-western China. Close contact with these birds is associated with a risk of zoonotic transmission of C. psittaci. Public education should be implemented to reduce the risk of avian to human transmission of such a pathogenic agent.

Assessment of genotoxic effects of flumorph by the comet assay in mice organs

The present study investigated the genotoxic effects of flumorph in various organs (brain, liver, spleen, kidney and sperm) of mice. The DNA damage, measured as comet tail length (µm), was determined using the alkaline comet assay. The comet assay is a sensitive assay for the detection of genotoxicity caused by flumorph using mice as a model. Statistically significant increases in comet assay for both dose-dependent and duration-dependent DNA damage were observed in all the organs assessed. The organs exhibited the maximum DNA damage in 96 h at 54 mg/kg body weight. Brain showed maximum DNA damage followed by spleen > kidney > liver > sperm. Our data demonstrated that flumorph had induced systemic genotoxicity in mammals as it caused DNA damage in all tested vital organs, especially in brain and spleen.

Deaths of tuberculosis patients in urban China: a retrospective cohort study

BACKGROUND

The case-fatality rate for tuberculosis (TB) remains high in China, whereas risk factors for deaths among TB cases are still unclear.

DESIGN

This was a retrospective cohort study of all pulmonary TB patients registered in four districts of Shanghai from 2004 to 2008. Data were derived from the China National TB Surveillance System. A total of 4271 patients were followed up in communities. Data were analysed using Cox regression.

RESULTS

The percentage of all-cause deaths in the study population was 15% 2-6 years after the most recent TB diagnosis. TB was responsible for only 17% of all deaths; male sex was significantly associated with all-cause deaths. After adjustment for sex, age and treatment history, four factors were significantly and independently associated with increased risk of death: psychopathy, chronic bronchitis, cancer and the presence of multiple diseases. TB was responsible for 7.2 potential years of life lost (PYLL); PYLL was higher in females (8.2) than males (5.3).

CONCLUSIONS

TB remains a significant problem in urban China. Implementation of improved clinical management, prevention strategies and other public health programmes should target TB patients with chronic conditions, particularly those with multiple diseases.

Observation of two new N* resonances in the decay ψ(3686)→ppπ0

Based on 106×10(6)ψ(3686) events collected with the BESIII detector at the BEPCII facility, a partial wave analysis of ψ(3686)→ppπ0 is performed. The branching fraction of this channel has been determined to be B(ψ(3686)→ppπ0)=(1.65±0.03±0.15)×10(-4). In this decay, 7 N* intermediate resonances are observed. Among these, two new resonances, N(2300) and N(2570) are significant, one 1/2+ resonance with a mass of 2300(-30-0)(+40+109)  MeV/c2 and width of 340(-30-58)(+30+110)  MeV/c2, and one 5/2- resonance with a mass of 2570(-10-10)(+19+34)  MeV/c2 and width of 250(-24-21)(+14+69)  MeV/c2. For the remaining 5 N* intermediate resonances [N(1440), N(1520), N(1535), N(1650) and N(1720)], the analysis yields mass and width values that are consistent with those from established resonances.

Establishment of Eimeria tenella (local isolate) in chicken embryos

Development of an in vitro Eimeria (E.) tenella model could be valuable as a tool for vaccine, coccidiostats or molecular biology research. 1.0 × 10,000 sporozoites per 0.1 mL were inoculated into the allantoic cavity of ten-day-old chicken embryos. The complete life-cycle of E. tenella was accomplished in eight-nine days at 37 °C and 70% humidity. The addition of 100 U insulin to the embryos could remarkably improve the output of oocysts. The development of the parasite within the embryos was systematically observed, allowing guidelines to be set regarding the appropriate times at which different developmental stages of the parasite may be sampled.