Genetic Control of Obesity and Gut Microbiota Composition in Response to High-Fat,High-Sucrose Diet in Mice

1. Download : Download high-res image (253KB)
2. Download : Download full-size image

Highlights? Detailed analysis of diet-induced obesity in more than 100 inbred mouse strains ? Identification of 11 genetic loci associated with obesity and dietary responsiveness ? Significant overlap between mouse loci with human GWAS loci for obesity ? Strain-specific shifts in gut microbiota composition in response to dietary intervention     

Isolation and functional characterization of a delta 6-desaturase gene from the pike eel (Muraenesox cinereus)

Stearidonic acid (STA; 18:4n-3) and γ-linolenic acid (GLA; 18:3n-6) are significant intermediates in the biosynthetic pathway for the very-long-chain polyunsaturated fatty acids of eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), respectively. To develop a sustainable system for the production of dietary polyunsaturated fatty acids, we focused on the action of the enzyme delta 6-desaturase (D6DES) on the essential acids, linoleic acid (LA; 18:2n-6) and α-linolenic acid (ALA; 18:3n-3). A 1,335-bp full-length cDNA encoding D6DES (McD6DES) was cloned from Muraenesox cinereus using degenerate PCR and RACE-PCR methods. To investigate the enzymatic activity of McD6DES in the production of n-6 and n-3 fatty acids, a recombinant plasmid expressing McD6DES (pYES-McD6DES) was transformed into and expressed in Saccharomyces cerevisiae. The exogenously expressed McD6DES produced GLA and STA at conversion rates of 14.2% and 45.9%, respectively, from the exogenous LA and ALA substrates. These results indicate that McD6DES is essentially a delta 6-desaturase involved in very-long-chain polyunsaturated fatty acid synthesis.     

Vitamin D-binding protein interacts with Aβ and suppresses Aβ-mediated pathology

The level of vitamin D-binding protein (DBP) is increased in the cerebrospinal fluid of patients with Alzheimer''s disease (AD), suggesting a relationship with its pathogenesis. In this study, we investigated whether and how DBP is related to AD using several different approaches. A pull-down assay and a surface plasmon resonance binding assay indicated direct interactions between purified DBP and amyloid beta (Aβ), which was confirmed in the brain of AD patients and transgenic AD model mice by immunoprecipitation assay and immunohistochemical double-staining method. Moreover, atomic force microscopic examination revealed that DBP reduced Aβ aggregation in vitro. DBP also prevented Aβ-mediated death in cultured mouse hippocampal HT22 cell line. Finally, DBP decreased Aβ-induced synaptic loss in the hippocampus and rescued memory deficits in mice after injection of Aβ into the lateral ventricle. These results provide converging evidence that DBP attenuates the harmful effects of Aβ by a direct interaction, and suggest that DBP is a promising therapeutic agent for the treatment of AD.     

Next-generation sequencing-based transcriptome analysis of l-lysine-producing Corynebacterium glutamicum ATCC 21300 strain

In the present study, 151 genes showed a significant change in their expression levels in Corynebacterium glutamicum ATCC 21300 compared with those of C. glutamicum ATCC 13032. Of these 151 genes, 56 genes (2%) were up-regulated and 95 genes (3%) were down-regulated. RNA sequencing analysis also revealed that 11 genes, involved in the L-lysine biosynthetic pathway of C. glutamicum, were up- or down-regulated compared with those of C. glutamicum ATCC 13032. Of the 151 genes, 10 genes were identified to have mutations including SNP (9 genes) and InDel (1 gene). This information will be useful for genome breeding of C. glutamicum to develop an industrial amino acid-producing strain with minimal mutation.     

Volatile fatty acid production from lignocellulosic biomass by lime pretreatment and its applications to industrial biotechnology

Lignocellulosic biomass was pretreated with lime, and used for the production of VFA (volatile fatty acid) through batch anaerobic digestion. About 0.34 g VFA yield was obtained using 10 g/L reed, after 3 days of fermentation with lime treatment; however, a higher VFA yield (more than 0.5 g/g biomass) was achieved with a modified lime treatment. Overall, our study showed that that the modified lime treatment is better suited for VFA production. VFAs can be widely used in platforms for fuels and chemicals from biomass.     

A novel thermostable cellulase free xylanase stable in broad range of pH from Streptomyces sp. CS428

A cellulase free thermostable xylanase from Streptomyces sp. CS428 was isolated from a Korean soil sample, purified by single-step chromatography, and biochemically characterized. The extracellular xylanase was purified 26 fold with a 55% yield by CM Trisacryl cation exchange chromatography. The molecular mass of the enzyme (Xyn428) was approximately 37 kDa. Xyn428 was found to be stable over a broad pH range (4 to ～13.6) and to 50 °C and have an optimum temperature of 80 °C. Xyn428 had K_m and V_max values of 102.3 ± 1.2 mg/mL and 3225.4 ± 15 mmol/min mg, respectively, when beechwood xylan was used as substrate. N-terminal sequence of Xyn428 was INRTDHNENSYLEIHNNEAR. CS428 was grown on different agro waste xylan and produced 4197.1 U/mL of xylanase activity in 36 h of cultivation in wheat bran without supplements. Xyn428 activity was inhibited by Tris salt at concentrations above 20 mM, and produced xylose and xylobiose as major products. It was found to degrade agro waste materials by small unit of enzyme (20 U/g) as shown by electron microscopy. As being simple in purification, thermo tolerant, pH stability in broad range and ability to produce xylooligosaccharides show that Xyn428 has potential applications in industries as a biobleaching agent and for xylooligosaccharides production.     

Fatty acid compositions of Taenia solium metacestode and its surrounding tissues

Fatty acids (FAs) are the main energy sources of living organisms and are the major components of cellular and organelle membranes. Their compositions also affect the flexibility/rigidity of cells and cell vitality. The Taenia solium metacestode (TsM) causes neurocysticercosis (NC), which is one of the most common helminthic infections of the central nerve system. We investigated the FA composition of the cyst fluid (CF) and parenchyma of the TsM, together with those of the granuloma and swine tissue surrounding the granuloma. The FA fractions of the TsM CF and swine tissue showed a composition and proportional contents comparable to each other, in which C18:0 (stearic acid), C18:1n9c (oleic acid), C20:4 (arachidonic acid) and C16:0 (palmitic acid) constituted the major fractions. However, the relative amount of individual FAs of the TsM parenchyma and granuloma differed from those of TsM CF and swine tissue, which contained enriched C16:0 and a lower amount of C20:4. Saturated FAs were the major constituents in parenchyma and granuloma, 50.4% and 46.1%, respectively. Conversely, monounsaturated FAs were the major constituents of CF and swine tissue, 38.7% and 40.3%, respectively. Our results strongly suggest that host-derived FAs might translocate across the parasite syncytial membrane and be stored in the CF.