Heterologous expression and purification of SpaB involved in subtilin biosynthesis

Lantibiotic peptides contain thioether bridges termed lanthionines that are putatively generated by dehydration of Ser and Thr residues followed by Michael addition of cysteine residues within the peptide. The LanB and LanC proteins have been proposed to catalyze the dehydration and formation of the thioether rings, respectively. We report here the first heterologous overexpression in Escherichia coli of SpaB, the putative dehydratase for subtilin. Sequence analysis of spaB revealed several nucleotide differences with current gene database entries. The solubility of SpaB was increased dramatically when co-expressed with GroEL/ES, and soluble His(6)-tagged SpaB was purified. The protein is at least a dimer, and interaction between SpaB and SpaC was observed. SpaS the putative substrate for SpaB was overexpressed in E. coli as an intein fusion protein, and after cleavage, the peptide was obtained in good yield.     

Molecular mechanism of diapause in insect (I)

The embryonic diapause of the silkworn,Bombyx mori, is induced by the diapause hormone (DH) which is secreted from the suboesophageal ganglion of pupae. The diapause nature of bivoltine strains uses environmental stimuli as the initial signal to determine the diapause nature. The experiments showed that DH gene expreon is a direct response to the environmend stimulus, such as high incubation temperature. The cDNA from the embryonic stage wa cloned and sequenm analysis showed the cDNA encoding DH. Expmion patterns of the DH gene in embryonic stage are different ar incubation temperatures 15°C and 25°C, suggesting that the incubation tempcreturt as an environmental signal is kept within the body to control the DH gene expmion at the pupal stage, so that the embryonic diapause of next generation can be determined.     

Tetracyclic sulfones as potent γ-secretase inhibitors: Synthesis and structure–activity relationship studies

Complex tetracyclic sulfones were designed as γ-secretase inhibitors and a stereoselective synthesis was achieved. γ-Secretase activity was seen predominately in the (?) enantiomeric series. Compounds such as 2a and 2b showed remarkable in vitro and in vivo potency.     

Catalytic removal of sulfide by an immobilized sulfide-oxidase bioreactor

A bioreactor packed with chitosan immobilized sulfide-oxidase from Streptomyces species LD048 was developed to treat a liquid stream of sulfide. The inoculation system was composed of glass with a 0.7 L working volume and enzyme activity of 2 mmol S g^?1 carrier. The sulfide removal efficiency was almost 100% when the volumetric loading was increased up to 3.9 mmol S L^?1 h^?1 at a space velocity of 18 h^?1. The maximal elimination capacity was 22.1 mmol S L^?1 h^?1 with a space velocity of 72 h^?1. When the aeration was increased from 0.05 to 0.1 L min^?1, the average removal efficiency improved from 81% to 94%. A removal efficiency of 90% was obtained after 15 days of operation with a load rate of 8.9 mmol S L^?1 h^?1 and a space velocity of 14.28 h^?1. An operational equation based on the ideal plug flow bioreactor and the Michaelis–Menten model predicted the performance of this bioreactor.     

Functional Pillared Graphene Frameworks for Ultrahigh Volumetric Performance Supercapacitors

Supercapacitors, also known as electrochemical capacitors, can provide much faster charge–discharge, greater power density, and cyclability than batteries, but they are still limited by lower energy densities (or the amount of energy stored per unit volume). Here, a novel strategy for the synthesis of functional pillared graphene frameworks, in which graphene fragments in‐between graphene sheets, through simple thermal‐treatment of ozone (O₃)‐treated graphene oxide at very low temperature of 200 °C is reported. Due to its high packing density, high content of stable oxygen species, and continues ion transport network in‐between graphene sheets, the functional pillared‐graphene framework delivers not only high gravimetric capacitance (353 F g^?1 based on the mass of the active material) and ultrahigh volumetric capacitance (400 F cm^?3 based on total mass of electrode material) in aqueous electrolyte but also excellent cyclic stability with 104% of its initial capacitance retention after 10 000 cycles. Moreover, the assembled symmetric supercapacitor achieves as high as 27 Wh L^?1 of volumetric energy density at a power density of 272 W L^?1. This novel strategy holds great promise for future design of high volumetric capacitance supercapacitors.     

Myc-Induced Liver Tumors in Transgenic Zebrafish Can Regress in tp53 Null Mutation

Hepatocellular carcinoma (HCC) is currently one of the top lethal cancers with an increasing trend. Deregulation of MYC in HCC is frequently detected and always correlated with poor prognosis. As the zebrafish genome contains two differentially expressed zebrafish myc orthologs, myca and mycb, it remains unclear about the oncogenicity of the two zebrafish myc genes. In the present study, we developed two transgenic zebrafish lines to over-express myca and mycb respectively in the liver using a mifepristone-inducible system and found that both myc genes were oncogenic. Moreover, the transgenic expression of myca in hepatocytes caused robust liver tumors with several distinct phenotypes of variable severity. ~5% of myca transgenic fish developing multinodular HCC with cirrhosis after 8 months of induced myca expression. Apoptosis was also observed with myca expression; introduction of homozygous tp53^-/- mutation into the myca transgenic fish reduced apoptosis and accelerated tumor progression. The malignant status of hepatocytes was dependent on continued expression of myca; withdrawal of the mifepristone inducer resulted in a rapid regression of liver tumors, and the tumor regression occurred even in the tp53^-/- mutation background. Thus, our data demonstrated the robust oncogenicity of zebrafish myca and the requirement of sustained Myc overexpression for maintenance of the liver tumor phenotype in this transgenic model. Furthermore, tumor regression is independent of the function of Tp53.     

Prevalence of Gestational Diabetes Mellitus and Its Risk Factors in Chinese Pregnant Women: A Prospective Population-Based Study in Tianjin,China

Objective

We compared the increases in the prevalence of gestational diabetes mellitus (GDM) based on the 1999 World Health Organization (WHO) criteria and its risk factors in Tianjin, China, over a 12-year period. We also examined the changes in the prevalence using the criteria of International Association of Diabetes and Pregnancy Study Group (IADPSG).

Methods

In 2010-2012, 18589 women who registered within 12 weeks of gestation underwent a glucose challenge test (GCT) at 24-28 gestational weeks. Amongst them, 2953 women with 1-hour plasma glucose ≥7.8 mmol/L underwent a 75-gram 2-hour oral glucose tolerance test (OGTT) and 781 women had a positive GCT but absented from the standard OGTT. An adjusted prevalence of GDM was calculated for the whole cohort of women by including an estimate of the proportion of women with positive GCTs who did not have OGTTs but would have been expected to have GDM. Logistic regression was used to obtain odds ratios and 95% confidence intervals using the IADPSG criteria. The prevalence of GDM risk factors was compared to the 1999 survey.

Results

The adjusted prevalence of GDM by the 1999 WHO criteria was 8.1%, a 3.5-fold increase as in 1999. Using the IADPSG criteria increased the adjusted prevalence further to 9.3%. Advanced age, higher pre-pregnancy body mass index, Han-nationality, higher systolic blood pressure (BP), a family history of diabetes, weight gain during pregnancy and habitual smoking were risk factors for GDM. Compared to the 1999 survey, the prevalence of overweight plus obesity had increased by 1.8 folds, age≥30 years by 2.3 folds, systolic BP by 2.3 mmHg over the 12-year period.

Conclusions

Increasing prevalence of overweight/obesity and older age at pregnancy were accompanied by increasing prevalence of GDM, further increased by change in diagnostic criteria.     

The Successful Diagnosis and Typing of Systemic Amyloidosis Using A Microwave-Assisted Filter-Aided Fast Sample Preparation Method and LC/MS/MS Analysis

Laser microdissection followed by mass spectrometry has been successfully used for amyloid typing. However, sample contamination can interfere with proteomic analysis, and overnight digestion limits the analytical throughput. Moreover, current quantitative analysis methods are based on the spectrum count, which ignores differences in protein length and may lead to misdiagnoses. Here, we developed a microwave-assisted filter-aided sample preparation (maFASP) method that can efficiently remove contaminants with a 10-kDa cutoff ultrafiltration unit and can accelerate the digestion process with the assistance of a microwave. Additionally, two parameters (P- and D-scores) based on the exponentially modified protein abundance index were developed to define the existence of amyloid deposits and those causative proteins with the greatest abundance. Using our protocol, twenty cases of systemic amyloidosis that were well-typed according to clinical diagnostic standards (training group) and another twenty-four cases without subtype diagnoses (validation group) were analyzed. Using this approach, sample preparation could be completed within four hours. We successfully subtyped 100% of the cases in the training group, and the diagnostic success rate in the validation group was 91.7%. This maFASP-aided proteomic protocol represents an efficient approach for amyloid diagnosis and subtyping, particularly for serum-contaminated samples.