[Genetic characterization of norovirus isolated in an outbreak of gastroenteritis in Jiangsu province]

Objective: To analyze the genetic characterization of norovirus isolated in an outbreak of gastroenteritis in Jiangsu province. Methods: Extracted viral RNA from the swab samples of cases of acute gastroenteritis outbreak in Jiangsu province on December 16-27, 2016 was reversely transcribed to cDNA, and partial RNA-dependent RNA polymerase sequence and complete capsid sequence (VP1) were amplified by RT-PCR. Amplification products were sequenced for the analysis of genetic characteristics. Results: Based on sequence alignment, the variant shared a high level of identity with the strain GⅡ.g isolated in Spain and Finland (98.7%) in the RNA-dependent RNA polymerase region, and with the strain GⅡ.1 isolated in American (99.4%) in the VP1. The recombination was determined by using software Simplot, and the breakpoint of recombination was located in the ORF1/2 overlap region at position 5 106 of VP1. The result of amino acids alignment in capsid region showed that there were no mutations in the amino acids of the predicted epitopes and receptor binding site Ⅰ-Ⅲ, but a unique amino acid change was detected at position 132 (N-S). Conclusion: The norovirus isolated in the outbreak of gastroenteritis in Jiangsu province was a rare recombinant norovirus variant GⅡ.g-GⅡ.1.

CDKN2B deletion is essential for pancreatic cancer development instead of unmeaningful co-deletion due to juxtaposition to CDKN2A

Pancreatic cancer is among the deadliest malignancies; however, the genetic events that lead to pancreatic carcinogenesis in adults remain unclear. In vivo models in which these genetic alterations occur in adult animals may more accurately reflect the features of human cancer. In this study, we demonstrate that inactivation of Cdkn2b (p15ink4b) is necessary for induction of pancreatic cancer by oncogenic KRAS^G12D expression and inactivation of Tp53 and Cdkn2a in adult mouse pancreatic ductal cells (P60 or older). KRAS^G12D overexpression in these cells activated transforming growth factor-β signaling and expression of CDKN2B, which, along with CDKN2A, led to cellular senescence and protected cells from KRAS-mediated transformation via inhibition of retinoblastoma phosphorylation. These results show a critical role of CDKN2B inactivation in pancreatic carcinogenesis, and provide a useful adult animal model by genetic engineering via lentiviral delivery.

[Analysis of clinical characteristics of necrotizing enterocolitis in term infants]

OBJECTIVE

To investigate the characteristics and outcomes of necrotizing enterocolitis (NEC) in Chinese term infants population.

METHODS

A national neonatal necrotizing enterocolitis network was established. Neonates as having necrotizing enterocolitis with gestation age ≥37 weeks were identified if they met the accepted diagnostic criterion during the study period from Jan 1(st) 2011 to Dec 31(st) 2011. The data of maternal and neonates' characteristics, the comorbidities, the clinical interventions prior to NEC, the clinical courses and radiology results, the medical and surgical treatment and the outcomes were collected. SPSS 19.0 software was used to do statistic analysis. Logistic-regression models were used to analyze the risk factors for death in infants with NEC, odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

There were 231 067 newborn infants, 164 307 of them were term infants, admitted to 95 hospitals in main land China. There were 718 term infants were diagnosed as necrotizing enterocolitis with the incidence of 0.44%. There were 294 term infants cases identified as ≥stage 2 necrotizing enterocolitis for the analysis, including 193 cases of stage 2 and 101 cases of stage 3.The mean gestation age was (39.0±1.3) weeks, and the mean birth weight was(3 087.4±548.3)g. The percentage of small for gestation age was 20.4%. The onset age of NEC was 5 (2-11)d. The percentage of cases received breast milk feeding was 23.7%. The most common comorbidities were sepsis (9.5%, 28/294), asphyxia (9.5%, 28/294), pneumonia (7.8%, 23/294) and congenital megacolon (7.5%, 22/294). The bowel perforation rate was 13.9%. The rate of cases who received surgical treatment was 25.2%(76.6% small intestinal necrosis and 65.8% small intestinal perforation). The mortality rate was 28.9%(the mortality rate were 20.7% and 44.6% in stage 2 and stage 3 NEC, respectively). Noninvasive continuous positive airway pressure treatment for NEC (OR=5.278, 95% CI: 2.058-13.533, P<0.01) and NEC staging 3 (OR=3.156, 95% CI: 1.766-5.642, P<0.01) were statistically significantly associated with mortality of NEC.

CONCLUSIONS

The term infants with necrotizing enterocolitis usually have the underlying comorbidities. The breastmilk feeding rate is low. Necrotizing enterocolitis remains high mortality in term neonates in Chinese neonatal units. Noninvasive continuous positive airway pressure treatment for NEC is statistically significantly associated with mortality of NEC.

MiRNA153 induces pituitary tumor MMQ cell line apoptosis through down-regulating Skp protein expression

OBJECTIVE

Pituitary tumor seriously threatens patient's life. MicroRNAs regulate cell growth and apoptosis. This study aims to investigate the effects of miRNA153 on pituitary tumor MMQ cells proliferation and apoptosis.

MATERIALS AND METHODS

Synthetic miRNA153 and control miRNA were transfected to MMQ cell line. Cell proliferation and apoptosis were tested by MTT assay and flow cytometry, respectively. Skp protein expression was detected by Western blot assay. Skp siRNA or Skp plasmid was transfected to MMQ cells transfected by miRNA153 to evaluate the influence on MMQ cell apoptosis.

RESULTS

MMQ cell proliferation was inhibited and apoptosis was enhanced after miRNA153 transfection. Skp protein level decreased in MMQ cells transfected by miRNA153. Skp interference enhanced MMQ cell apoptosis induced by miRNA153. Skp overexpression restrained MMQ cell apoptosis triggered by miRNA153.

CONCLUSIONS

MiRNA153 transfection suppressed MMQ cell growth and induced apoptosis. MiRNA153 regulated MMQ cell apoptosis through down-regulating Skp protein.

Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak

The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k_⊥max ≤ 2 cm^-1 and time response up to 350 kHz. Feasibility of the diagnostic has been tested, showing higher sensitivity to detect fluctuation than interferometric measurement. Capability of providing spatial-resolved information of fluctuation has also been demonstrated in preliminary experimental applications.

Multiprotein bridging factor 2 regulates the expression of the fibroin heavy chain gene by interacting with Bmdimmed in the silkworm Bombyx mori

Multiprotein bridging factor 2 (MBF2) was first isolated from the posterior silk gland of Bombyx mori. However, its function in B. mori is still unknown. Herein, MBF2 transcripts were detected mainly in the posterior silk gland and Malpighian tubules of B. mori larvae via a quantitative PCR analysis. An analysis of temporal expression patterns showed that the expression pattern of MBF2 was the opposite of that of the fibroin heavy chain (fibH) gene, as its expression was high during the fourth-instar moulting stage, decreased gradually during the fifth-instar feeding stage and disappeared at the end of the fifth-instar phase. Furthermore, bimolecular fluorescent complementation and Far-Western blot assays showed that MBF2 interacted with the basic helix-loop-helix transcription factor Bmdimmed. Dual luciferase reporter assays showed that MBF2 down-regulated the promoter activity of fibH and inhibited the effect of Bmdimmed (Bmdimm) on fibH expression. MBF2 expression was induced in silk glands after treatment with 20-hydroxyecdysone in vivo and in vitro. These findings suggest that MBF2 is a transcriptional repressor that is involved in controlling the regulation of the fibH gene in the posterior silk gland by interacting with Bmdimm.

Facile synthesis of manganese silicate nanoparticles for pH/GSH-responsive T1-weighted magnetic resonance imaging

Manganese silicate nanoparticles were facilely synthesized and showed high potential as T₁-MRI contrast agents for cancer diagnosis.

Density modulation experiment to determine transport coefficients on Joint-TEXT Tokamak

Density modulation experiments have been conducted on Joint-TEXT (J-TEXT) Tokamak Ohmic discharge to investigate particle transport based on a model with constant diffusion plus inward convection. Like the HCN interferometer, the newly developed three-wave polarimeter-interferometer system (POLARIS) is used to measure the perturbed density. The comparison of results between the HCN interferometer and POLARIS is given. The consistent results indicate the validity of the analysis scheme. At lower densities, the typical particle confinement time τp is found to increase with electron density, while it saturates at higher densities.

Metabolomics analysis of cervical cancer, cervical intraepithelial neoplasia and chronic cervicitis by 1H NMR spectroscopy

Metabolomics profiles of serum samples from women with chronic cervicitis, cervical intraepithelial neoplasia (CIN), and cervical cancer were characterized by proton nuclear magnetic resonance (1H NMR). These spectral profiles were subjected to partial least-squares discriminant analysis (PLS-DA), and good discriminations between cancerand non-cancer groups (chronic cervicitis and CIN) were achieved by multivariate modeling of serum profiles. The main metabolites contributing to these discriminations, as highlighted by multivariate analysis and confirmed by spectral integration, were formate, tyrosine, β-glucose, inositol, glycine, carnitine, glutamine, acetate, alanine, valine, isoleucine, and very-low-density lipoprotein (VLDL). Metabolomics analysis for chronic cervicitis, CIN, and cervical cancer is significant, which give a systemic metabolic response of these female diseases. The systemic metabolic response may be used to identify the potential biomarkers for the diseases.

Propagation of shear elastic and electromagnetic waves in one dimensional piezoelectric and piezomagnetic composites

Coupled shear (SH) elastic and electromagnetic (EM) waves propagating oblique to a one dimensional periodic piezoelectric and piezomagnetic composite are investigated using the transfer matrix method. Closed-form expression of the dispersion relations is derived. We find that the band structures of the periodic composite show simultaneously the features of phononic and photonic crystals. Strong interaction between the elastic and EM waves near the center of the Brillouin zone (i.e., phonon-polariton) is revealed. It is shown the elastic branch of the band structures is more sensitive to the piezoelectric effect while the phonon-polariton is more sensitive to the piezomagnetic effect of the composite.

Genetic diversity and expression profiles of cysteine phytases in the sheep rumen during a feeding cycle

Cysteine phytase is the main phytate-degrading enzyme of ruminant animals. To explore the genetic diversity and dynamic expression profile of cysteine phytase in sheep rumen during a feeding cycle, four transcript (0, 4, 9 and 16 h after feeding) and one DNA (9 h after feeding) clone libraries were constructed, respectively. A total of 46 distinct gene fragments were identified, and most of these sequences had low identities (<60%) with known phytases. Great divergence was found in the constitution and abundance of genes at the genome and transcriptional levels, and the transcript data are more reliable to reflect the information of functional genes. Phylogenetic analysis indicated that the genes from uncultured bacteria instead of Firmicutes played the major phytate-degrading role. Further comparative analysis revealed the dynamic constitution of cysteine phytase genes in rumen at different time points.

SIGNIFICANCE AND IMPACT OF THE STUDY

Ruminal phytases, that are cysteine phytases, are novel in sequences and functions. Great divergence in the constitution and abundance of cysteine phytase genes at the genome and transcriptional levels suggested that transcript data are more reliable to reflect the information of functional genes. Phylogenetic and rarefaction analyses indicated that the cysteine phytase genes from uncultured bacteria instead of Firmicutes play the major phytate-degrading role in rumen, and their constitution is dynamic at different time points. This study provides a new insight into ruminal cysteine phytase genes and undermines their expression profiles over a whole feeding cycle.

A quantitative recipe for engineering protein polymer nanoparticles

Protein polymers can assemble switchable nanostructures with emerging applications as biomaterials and nanomedicines. For example, above a critical micelle temperature (CMT) some elastin-like polypeptide (ELP) diblock copolymers assemble spherical nanoparticles, which may modulate cellular internalization and in vivo biodistribution. To achieve engineering-level control over their properties, this report explores a comprehensive library of ELP monoblock and diblock polymers. For the first time, we report that a surprisingly high core molecular weight is required for stable nanoparticle formation; furthermore, nanoparticle size depends on polymer molecular weight. A mathematical model was developed to characterize four ELP monoblock libraries and to predict the phase behavior of corresponding diblock copolymers. The CMT was almost entirely dependent on the hydrophobic core ELP, while the bulk phase transition temperature (T_t,bulk ) depends predominantly on the hydrophilic block. Nanoparticle assembly was accompanied by a conversion in secondary structure of the hydrophobic block from random coil and beta-sheets to type-2 β turns. For the first time, this report enables the rational design of ELP protein polymer nanoparticles with physico-chemico properties that will be suitable for biological applications.

Kinetic quantification of protein polymer nanoparticles using non-invasive imaging

Protein polymers are repetitive amino acid sequences that can assemble monodisperse nanoparticles with potential applications as cancer nanomedicines. Of the currently available molecular imaging methods, positron emission tomography (PET) is the most sensitive and quantitative; therefore, this work explores microPET imaging to track protein polymer nanoparticles over several days. To achieve reliable imaging, the polypeptides were modified by site-specific conjugation using a heterobifunctional sarcophagine chelator, AmBaSar, which was subsequently complexed with (64)Cu. AmBaSar/(64)Cu was selected because it can label particles in vivo over periods of days, which is consistent with the timescales required to follow long-circulating nanotherapeutics. Using an orthotopic model of breast cancer, we observed four elastin-like polypeptides (ELPs)-based protein polymers of varying molecular weight, amino acid sequence, and nanostructure. To analyze this data, we developed a six-compartment image-driven pharmacokinetic model capable of describing their distribution within individual subjects. Surprisingly, the assembly of an ELP block copolymer (78 kD) into nanoparticles (R(h) = 37.5 nm) minimally influences pharmacokinetics or tumor accumulation compared to a free ELP of similar length (74 kD). Instead, ELP molecular weight is the most important factor controlling the fate of these polymers, whereby long ELPs (74 kD) have a heart activity half-life of 8.7 hours and short ELPs (37 kD) have a half-life of 2.1 hours. These results suggest that ELP-based protein polymers may be a viable platform for the development of multifunctional therapeutic nanoparticles that can be imaged using clinical PET scanners.

Effect of Hot Water and Water-carrying Agent on the Properties of Silane-water Crosslinked Linear Low Density Polyethylene

The influence of hot water and the water-carrying agent aluminum potassium sulfate dodecahydrate (alum) on the mechanical and thermal properties of the silane-water crosslinked linear low density polyethylene (LLDPE) was investigated. LLDPE was melt-grafted with various content of vinyl trimethoxysilane (VTMS) using dicumyl peroxide (DCP) as initiator. The results show that the contribution of hot water to gel content is poor, about 2 to 16%, compared with that of the silane grafted LLDPE. Is feasible to achieve silane-water crosslinking reaction with alum for self-crosslinked LLDPE; furthermore, the self-crosslinked LLDPE has lower crosslink density (ν). It was found that alum could not only conduct silane-water crosslinking reaction effectively, but also improve the mechanical properties, especially the elongation behavior. The heat of fusion (ΔHm), the melting temperature (Tm), and the degree of crystallinity (Xc) of the hot water crosslinked LLDPE decreased with the advancement of VTMS. The Avrami exponent n of self-crosslinked sample was larger than that of hot water crosslinked sample. This means that the alum could contribute to the growth of crystallization.

Comparison of morphological and molecular genetic quantification of relative abundance of arbuscular mycorrhizal fungi within roots

Nested PCR amplicons of ribosomal RNA genes have been used to identify individuals within assemblages of arbuscular mycorrhizal (AM) fungi in roots and to estimate their relative abundance. Microscopy has also been used to identify their relative abundance in roots, but only at low resolution, usually the genus level. We evaluated the robustness of using nested PCR amplicons of ribosomal RNA genes to estimate the relative abundance of undefined AM fungi in uniformly aged roots in comparison to visual estimates. The relative abundance of AM fungi was assessed as per cent root length colonised by morphotypes and relative sequence type abundance in clone libraries. Plants were grown in coastal soil to obtain assemblages of unknown AM fungi at two times (spring and autumn). Relative abundance of dominant genera of AM fungi in roots (Archaeospora and Glomus) based on an analysis of ribosomal RNA genes did not consistently correspond with relative abundance of morphotypes. This microscopic vs. molecular genetic comparison supports previous conclusions that there can be limitations in using nested PCR amplicons for quantifying the relative abundance of AM fungi in roots, with a sampling bias likely to be of significance. Both molecular genetic and morphological methods are used to estimate relative abundance of AM fungi as a precursor to understanding mycorrhizal function in field soils, but they are rarely verified using alternative approaches although this may be necessary.