High-fidelity gene synthesis by retrieval of sequence-verified DNA identified using high-throughput pyrosequencing

The construction of synthetic biological systems involving millions of nucleotides is limited by the lack of high-quality synthetic DNA. Consequently, the field requires advances in the accuracy and scale of chemical DNA synthesis and in the processing of longer DNA assembled from short fragments. Here we describe a highly parallel and miniaturized method, called megacloning, for obtaining high-quality DNA by using next-generation sequencing (NGS) technology as a preparative tool. We demonstrate our method by processing both chemically synthesized and microarray-derived DNA oligonucleotides with a robotic system for imaging and picking beads directly off of a high-throughput pyrosequencing platform. The method can reduce error rates by a factor of 500 compared to the starting oligonucleotide pool generated by microarray. We use DNA obtained by megacloning to assemble synthetic genes. In principle, millions of DNA fragments can be sequenced, characterized and sorted in a single megacloner run, enabling constructive biology up to the megabase scale.     

Mesenchymal stem cells: Molecular characteristics and clinical applications

Mesenchymal stem cells (MSCs) are non-hematopoietic stem cells with the capacity to differentiate into tissues of both mesenchymal and non-mesenchymal origin. MSCs can differentiate into osteoblastic, chondrogenic, and adipogenic lineages, although recent studies have demonstrated that MSCs are also able to differentiate into other lineages, including neuronal and cardiomyogenic lineages. Since their original isolation from the bone marrow, MSCs have been successfully harvested from many other tissues. Their ease of isolation and ex vivo expansion combined with their immunoprivileged nature has made these cells popular candidates for stem cell therapies. These cells have the potential to alter disease pathophysiology through many modalities including cytokine secretion, capacity to differentiate along various lineages, immune modulation and direct cell-cell interaction with diseased tissue. Here we first review basic features of MSC biology including MSC characteristics in culture, homing mechanisms, differentiation capabilities and immune modulation. We then highlight some in vivo and clinical evidence supporting the therapeutic roles of MSCs and their uses in orthopedic, autoimmune, and ischemic disorders.     

Differential regulation of hepatic cytochrome P450 monooxygenases in streptozotocin-induced diabetic rats

The present investigation was carried out to study the expression of major cytochrome P450 (CYP) isozymes in streptozotocin-induced diabetes with concomitant insulin therapy. Male Sprague-Dawley rats were randomly assigned to untreated control, streptozotocin-induced diabetic, insulin-treated groups and monitored for 4 weeks. Uncontrolled hyperglycemia in the early phase of diabetes resulted in differential regulation of cytochrome P450 isozymes. CYP1B1, CYP1A2, heme oxygenase (HO)-2 proteins and CYP1A2-dependent 7-ethoxyresorufin O-deethylase (EROD) activity were upregulated in the hepatic microsomes of diabetic rats. Insulin therapy ameliorated EROD activity and the expression of CYP1A2, CYP1B1 and HO-2 proteins. In addition, CYP2B1 and 2E1 proteins were markedly induced in the diabetic group. Insulin therapy resulted in complete amelioration of CYP2E1 whereas CYP2B1 protein was partially ameliorated. By contrast, CYP2C11 protein was decreased over 99% in the diabetic group and was partially ameliorated by insulin therapy. These results demonstrate widespread alterations in the expression of CYP isozymes in diabetic rats that are ameliorated by insulin therapy.     

Fibrogenic cytokine levels in bronchoalveolar lavage aspirates 15 years after exposure to sulfur mustard

Over 100,000 Iranian war veterans suffer from chronic effects of mustard gas exposure. Sulfur mustard was used by Iraq during the Iraqi-imposed war on Iran (between 1980 and 1988). The major complaints of these patients are mild interstitial fibrosis and bronchiolitis. We aimed to determine the state of fibrosis progression and assessed transforming growth factor (TGF)-beta1 levels in pulmonary samples and in bronchoalveolar lavage (BAL) aspirates. A total of 126 war veterans confirmed for lung disease were assessed and compared with three control groups: 1) 64 veterans not exposed to chemical agents, 2) 12 idiopathic pulmonary fibrosis civilian patients, and 3) 33 normal persons. BAL was performed via a flexible fiber-optic bronchoscope and the standard manual method. Total protein was measured by Bradford assay, and samples were corrected with regard to coefficients. Samples were concentrated 15-fold by lyophilization and resolubilization. Samples were double-checked using an ELISA test kit. The Mann-Whitney test was used for the data analysis using commercial software. We detected that significant differences between TGF-beta1 levels between the case group and control group 1 (P = 0.001) and control group 3 (P = 0.003). No significant differences were found between the case group and control group 2 (P = 0.57). Inflammation and fibrotic processes in lung tissue of patients exposed to sulfur mustard may be progressive so IFN-gamma may be a useful drug to these patients' treatment.     

Phytoseiid mites (Acari: Mesostigmata) associated with tea gardens in north of Iran

Predator mites of Phytoseiidae family are among the most important biocontrol agents in the world. These beneficial mites are considered as natural enemies of many pests and herbivore mites, and can feed on different growth stages of pests (egg, larva or nymph). Five species of Phytoseiidae mites were found during a survey conducted on tea plants, Camellia sinensis (Theaceae), in the Mazandaran and Guilan Provinces in the north of Iran, on the coast of the Caspian Sea, the major tea-growing region of Iran. Some of these species are recorded for the first time in tea gardens of Iran.     

Efficacy of some plants as a post-harvest protectant against some major stored pests

The toxicity of vapours of the essential oil of Ferula gummosa, Elettaria cardamomum and Salvia officinalis on the adults and larvae of some stored product pests was investigated. The bioassays were carried out in 70 mL vials containing 10 individuals of each insect. The LC₅₀ values of fumigant bioassay after 24 h were calculated. Results indicated that the effect of the essential oil of F.gummosa was stronger than E. cardamomum, S. officinalis on stored pests. Also fumigant toxicity of S. officinalis on Sitophilus oryzae was similar to that of Sitophilus granarius adults. On the other hand, R. officinalis had a good effect on adults of Tribolium castaneum and larvae of Ephestia kuehniella. According to our results and good effect of these compounds, they will be a safe replace for chemical compounds in the future.     

Prevalence of Hypertension in Chinese Cities: A Meta-Analysis of Published Studies

Background

Hypertension has been recognized as a health concern for developing countries. However, there are no current nationwide surveys on the prevalence of hypertension in China (the latest nationwide survey was ten years ago). The goal of this study was to estimate the pooled prevalence of hypertension in Chinese cities.

Methods

We systematically reviewed published epidemiologic studies on the prevalence of hypertension in Chinese cities through meta-analysis. We searched for studies published between January 2002 and June 2012 using PubMed and two Chinese electronic publication libraries. The keywords ‘hypertension’ and ‘prevalence’ were used. Before pooling prevalence of hypertension, all raw prevalence data was age adjusted to the 2010 China standard population. Prevalence estimates were stratified by sex and geographic area.

Results

27 studies were identified with of a total of 195,027 study participants. The overall pooled prevalence of hypertension was 21.5% (19.4%, 23.6%). Subgroup analyses showed the following results north 25.8% (21.6%, 30.0%), south 20.4% (18.6%, 22.2%); male 22.2% (19.3%, 25.1%), female 19.9% (17.6%, 22.1%); large cities 18.9% (15.7%, 22.1%), medium-sized cities 24.6% (19.9%, 29.4%), small cities 20.6% (17.5%, 23.7%); study years in 2002–2006, 21.9% (18.9%, 24.8%), and study year in 2007–2011, 20.6% (17.3%, 23.9%).

Conclusions

Comparing data from several previous national hypertension surveys, the prevalence of hypertension is higher in cities than the Chinese national average. Subgroup studies also found a higher prevalence of hypertension in northern cities and among males. Also, the prevalence of hypertension in medium-sized and small cities is likely to increase faster than in large cities.     

Theoretical investigation on the selective detection of SO2 molecule by AlN nanosheets

A density functional theory investigation of adsorption of monomer, dimer and trimer forms of pyrrole on the outer surface of zigzag (7,0) single-walled carbon nanotube (SWCNT) has been reported. Geometries of the complexes were optimized using the M06-2X functional and the 6-31G(d,p) basis set. Moreover, 6-311G(d,p), cc-pVDZ and cc-pVTZ basis sets were used for the adsorption energy calculation and such energies were corrected for the basis set superposition error. Vertical ionization potential and electron affinity of the investigated system were also computed. The interaction of polypyrrole on the SWCNT surface is characterized by the stacking interaction. Adsorption (binding) energy of pyrrole on the SWCNT surface is weak, but such energy increases with the number of monomer units in the pyrrole oligomer. In the SWCNT-pyrrole complexes, the oxidation and reduction processes will take place only at the SWCNT. The influence of larger unit on the electronic properties of the complex has been detailed.