1,3-Propandiol production by engineered Hansenula polymorpha expressing dha genes from Klebsiella pneumoniae

Currently, 1,3-propanediol (1,3-PD) is an important chemical widely used in polymer production, but its availability is being restricted owing to its expensive chemical synthesis. A methylotrophic yeast Hansenula polymorpha was engineered by expression of dhaB1, dhaB2, dhaB3, dhaB _RA1 and dhaB _RA2 encoding glycerol dehydratase complex and dhaT encoding 1,3-PD oxidoreductase from Klebsiella pneumoniae under direction of promoter of glyceraldehyde-3 phosphate dehydrogenase (GAPDH). The engineered recombinant yeast strain can produce 1,3-PD from glucose (2.4 g L⁻¹) as well as glycerol (0.8 g L⁻¹), which might lead to a safe and cost-effective method for industrial production of 1,3-PD from various biomass resources.     

Enzyme precipitate coatings of lipase on polymer nanofibers

Lipase (LP) was immobilized on electrospun and ethanol-dispersed polystyrene–poly(styrene-co-maleic anhydride) (PS–PSMA) nanofibers (EtOH-NF) in the form of enzyme precipitate coatings (EPCs). LP precipitate coatings (EPCs-LP) were prepared in a three-step process, consisting of covalent attachment, LP precipitation, and crosslinking of precipitated LPs onto the covalently attached LPs via glutaraldehyde treatment. The LP precipitation was performed by adding various concentrations of ammonium sulfate (20–50%, w/v). EPCs-LP improved the LP activity and stability when compared to covalently attached LPs (CA-LP) and the enzyme coatings of LPs (EC-LP) without the LP precipitation. For example, the use of 40% (w/v) ammonium sulfate resulted in EPC40-LP with the highest activity, which was 4.0 and 3.6 times higher than those of CA-LP and EC-LP, respectively. After 165-day incubation under rigorous shaking at 200 rpm, the residual activities of EPC50-LP were 0.5 μM/min mg of EtOH-NF, representing 113 and 75 times higher than those of CA-LP and EC-LP, respectively. When LP was partially purified via a simple ammonium sulfate precipitation and dialysis, both activities and stabilities of EC-LP and EPC-LP could be marginally improved. It is anticipated that the improved LP activity and stability in the form of EPCs would allow for their potential applications in various bioconversion processes such as biodiesel production and ibuprofen resolution.     

Proteome changes in rat plasma in response to sibutramine

Sibutramine is an anti-obesity agent that induces weight loss by selective inhibition of neuronal reuptake of serotonin and norepinephrine; however, it is associated with the risk of cardiovascular diseases (CVD), including heart attack and stroke. Here, we analyzed global protein expression patterns in plasma of control and sibutramine-treated rats using proteomic analysis for a better understanding of the two conflicting functions of this drug, appetite regulation, and cardiovascular risk. The control (n=6) and sibutramine-treated groups (n=6) were injected by vehicle and sibutramine, respectively, and 2-DE combined with MALDI-TOF/MS were performed. Compared to control rats, sibutramine-administered rats gained approximately 18% less body weight and consumed about 13% less food. Plasma leptin and insulin levels also showed a significant decrease in sibutramine-treated rats. As a result of proteomic analysis, 23 differentially regulated proteins were discovered and were reconfirmed by immunoblot analysis. Changed proteins were classified into appetite regulation and cardiovascular risk, according to their regulation pattern. Because the differential levels of proteins that have been well recognized as predictors of CVD risk were not well matched with the results of our proteomic analysis, this study does not conclusively prove that sibutramine has an effect on CVD risk.     

The complete mitochondrial genome sequence of the Kori salamander Hynobius yangi (Caudata: Hynobiidae)

The complete mitochondrial genome (JN415127) was sequenced and annotated newly from an individual of Hynobius yangi populations which were collected in Ulju-gun, Korea. The total length of the H. yangi genome is 16,403 bp, with a total base composition of 33.5% A, 32.3% T, 20.5% C, and 13.6% G.     

Mitochondrial genome sequences of the striped field mice Apodemus agrarius coreae and Apodemus agrarius chejuensis

We determined the complete mitochondrial (mt) genome sequences of the striped field mice Apodemus agrarius coreae and Apodemus agrarius chejuensis. The mt genomes of A. a. coreae and A. a. chejuensis are 16,260 and 16,261 base pairs in length, respectively. The general features of the 13 protein-coding genes of the two species are similar to those of other rodents. The TAG termination codon for NADH dehydrogenase subunit (ND) 3 is unique to Apodemus in the Muroidea. The L-strand replication origin has the potential to form a stable stem-loop structure. Within the control region, a termination-associated sequence and several conserved sequence blocks were observed. The diversity of the 13 protein-coding genes, 2 rRNAs, and 1 control region between the two species ranged between 0.005 (ATP8) and 0.027 (ND4L).     

Complete mitochondrial genome sequence of the Korean water deer Hydropotes inermis argyropus (Cervidae, Capreolinae)

The complete mitochondrial genome sequence of Hydropotes inermis argyropus consists of 13 protein-coding, 22 tRNA, and two rRNA genes, and 1 control region (CR). Three overlaps among the 13 protein-coding genes were found: ATP8/ATP6, ND4L/ND4, and ND5/ND6. The CR was located between the tRNA-Pro and tRNA-Phe genes and is 928 bp in length. The typical conserved domains, such as TAS and CSB, were identified in the CR.     

Oncogenic CagA promotes gastric cancer risk via activating ERK signaling pathways: a nested case-control study

Background

CagA cellular interaction via activation of the ERK signaling pathway may be a starting point in the development of gastric cancer. This study aimed to evaluate whether genes involved in ERK downstream signaling pathways activated by CagA are susceptible genetic markers for gastric cancer.

Methods

In the discovery phase, a total of 580 SNPs within +/−5 kbp of 30 candidate genes were genotyped to examine an association with gastric cancer risk in the Korean Multi-center Cancer Cohort (100 incident gastric cancer case-control sets). The most significant SNPs (raw or permutated p value<0.02) identified in the discovery analysis were re-evaluated in the extension phase using unconditional logistic regression model (400 gastric cancer case-control sets). Combined analyses including pooled- and meta-analysis were conducted to summarize all the results.

Results

24 SNPs in eight genes (ERK, Dock180, C3G, Rap1, Src, CrkL, Mek and Crk) were significantly associated with gastric cancer risk in the individual SNP analyses in the discovery phase (p<0.05). In the extension analyses, ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 showed marginally significant gene-dose effects for gastric cancer. Consistently, final combined analysis presented the SNPs as significantly associated with gastric cancer risk (OR = 1.56, [95% CI: 1.19–2.06], OR = 0.61, [95% CI: 0.43–0.87], OR = 0.59, [95% CI: 0.54–0.76], respectively).

Conclusions

Our findings suggest that ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 are genetic determinants in gastric carcinogenesis.     

Geographic variation in advertisement calls in a tree frog species: gene flow and selection hypotheses

Background

In a species with a large distribution relative to its dispersal capacity, geographic variation in traits may be explained by gene flow, selection, or the combined effects of both. Studies of genetic diversity using neutral molecular markers show that patterns of isolation by distance (IBD) or barrier effect may be evident for geographic variation at the molecular level in amphibian species. However, selective factors such as habitat, predator, or interspecific interactions may be critical for geographic variation in sexual traits. We studied geographic variation in advertisement calls in the tree frog Hyla japonica to understand patterns of variation in these traits across Korea and provide clues about the underlying forces for variation.

Methodology

We recorded calls of H. japonica in three breeding seasons from 17 localities including localities in remote Jeju Island. Call characters analyzed were note repetition rate (NRR), note duration (ND), and dominant frequency (DF), along with snout-to-vent length.

Results

The findings of a barrier effect on DF and a longitudinal variation in NRR seemed to suggest that an open sea between the mainland and Jeju Island and mountain ranges dominated by the north-south Taebaek Mountains were related to geographic variation in call characters. Furthermore, there was a pattern of IBD in mitochondrial DNA sequences. However, no comparable pattern of IBD was found between geographic distance and call characters. We also failed to detect any effects of habitat or interspecific interaction on call characters.

Conclusions

Geographic variations in call characters as well as mitochondrial DNA sequences were largely stratified by geographic factors such as distance and barriers in Korean populations of H. japoinca. Although we did not detect effects of habitat or interspecific interaction, some other selective factors such as sexual selection might still be operating on call characters in conjunction with restricted gene flow.