Programming human pluripotent stem cells into white and brown adipocytes

The utility of human pluripotent stem cells is dependent on efficient differentiation protocols that convert these cells into relevant adult cell types. Here we report the robust and efficient differentiation of human pluripotent stem cells into white or brown adipocytes. We found that inducible expression of PPARG2 alone or combined with CEBPB and/or PRDM16 in mesenchymal progenitor cells derived from pluripotent stem cells programmed their development towards a white or brown adipocyte cell fate with efficiencies of 85%–90%. These adipocytes retained their identity independent of transgene expression, could be maintained in culture for several weeks, expressed mature markers and had mature functional properties such as lipid catabolism and insulin-responsiveness. When transplanted into mice, the programmed cells gave rise to ectopic fat pads with the morphological and functional characteristics of white or brown adipose tissue. These results indicate that the cells could be used to faithfully model human disease.Stem Cell and Regenerative Biolog

Genomes of two new ammonia-oxidizing archaea enriched from deep marine sediments.

Ammonia-oxidizing archaea (AOA) are ubiquitous and abundant and contribute significantly to the carbon and nitrogen cycles in the ocean. In this study, we assembled AOA draft genomes from two deep marine sediments from Donghae, South Korea, and Svalbard, Arctic region, by sequencing the enriched metagenomes. Three major microorganism clusters belonging to Thaumarchaeota, Epsilonproteobacteria, and Gammaproteobacteria were deduced from their 16S rRNA genes, GC contents, and oligonucleotide frequencies. Three archaeal genomes were identified, two of which were distinct and were designated Ca. "Nitrosopumilus koreensis" AR1 and "Nitrosopumilus sediminis" AR2. AR1 and AR2 exhibited average nucleotide identities of 85.2% and 79.5% to N. maritimus, respectively. The AR1 and AR2 genomes contained genes pertaining to energy metabolism and carbon fixation as conserved in other AOA, but, conversely, had fewer heme-containing proteins and more copper-containing proteins than other AOA. Most of the distinctive AR1 and AR2 genes were located in genomic islands (GIs) that were not present in other AOA genomes or in a reference water-column metagenome from the Sargasso Sea. A putative gene cluster involved in urea utilization was found in the AR2 genome, but not the AR1 genome, suggesting niche specialization in marine AOA. Co-cultured bacterial genome analysis suggested that bacterial sulfur and nitrogen metabolism could be involved in interactions with AOA. Our results provide fundamental information concerning the metabolic potential of deep marine sedimentary AOA

Depot-Specific Changes in Fat Metabolism with Aging in a Type 2 Diabetic Animal Model - Fig 1

<p><b>The effect of aging on the weight of subcutaneous fat/visceral fat ratio (A), OGTT (B), AUC during OGTT (C), adipocyte size distribution of subcutaneous fat (D) and visceral fat (E), and PPARγ2 mRNA levels (F).</b> (*<i>P</i> <0.05 vs. the same deposit in the untreated OLETF rats, ^†<i>P</i><0.05 vs. subcutaneous fat in the same group.)</p

Comparison of metabolic parameters measured in rats with aging or PPARγ agonist treatment.

<p>Comparison of metabolic parameters measured in rats with aging or PPARγ agonist treatment.</p

The effects of aging on the genes involved in fatty acid oxidation and energy expenditure.

<p>The effects of aging on the gene expression were analyzed by 2-way ANOVA (*<i>P</i> <0.05 vs. OLETF rats at 21 weeks of age). The effects of rosiglitazone on the metabolic genes in each fat depot were evaluated among the different groups at 21 weeks (†<i>P</i> <0.05 vs. the same deposit in OLETF rats at 21 weeks; RGZ, rosiglitazone treated).</p

The effects of aging on the genes involved in glycerol and fatty acid recycling.

<p>The effects of aging on the gene expression were analyzed by 2-way ANOVA (*<i>P</i> <0.05 vs. OLETF rats at 21 weeks of age). The effects of rosiglitazone on the metabolic genes in each fat depot were evaluated among the different groups at 21 weeks (†<i>P</i> <0.05 vs. the same deposit in OLETF rats at 21 weeks; RGZ, rosiglitazone treated).</p

Sequences of primers and PCR reaction parameters used in real-time RT-PCR.

<p>Sequences of primers and PCR reaction parameters used in real-time RT-PCR.</p

The effects of aging on the genes involved in adipose fatty acid uptake, esterification and triacylglycerol synthesis.

<p>The effects of aging on the gene expression were analyzed by 2-way ANOVA (*<i>P</i> <0.05 vs. OLETF rats at 21 weeks of age). The effects of rosiglitazone on the metabolic genes in each fat depot were evaluated among the different groups at 21 weeks (†<i>P</i> <0.05 vs. the same deposit in OLETF rats at 21 weeks; RGZ, rosiglitazone treated).</p

Correction to: Genomic and metatranscriptomic analyses of carbon remineralization in an Antarctic polynya

Following publication of the original article [1], the authors identified wrong citations in the maintext

Genomic and metatranscriptomic analyses of carbon remineralization in an Antarctic polynya

Abstract Background Polynyas in the Southern Ocean are regions of intense primary production, mainly by Phaeocystis antarctica. Carbon fixed by phytoplankton in the water column is transferred to higher trophic levels, and finally, to the deep ocean. However, in the Amundsen Sea, most of this organic carbon does not reach the sediment but is degraded in the water column due to high bacterial heterotrophic activity. Results We reconstructed 12 key bacterial genomes from different phases of bloom and analyzed the expression of genes involved in organic carbon remineralization. A high correlation of gene expression between the peak and decline phases was observed in an individual genome bin-based pairwise comparison of gene expression. Polaribacter belonging to Bacteroidetes was found to be dominant in the peak phase, and its transcriptional activity was high (48.9% of the total mRNA reads). Two dominant Polaribacter bins had the potential to utilize major polymers in P. antarctica, chrysolaminarin and xylan, with a distinct set of glycosyl hydrolases. In the decline phase, Gammaproteobacteria (Ant4D3, SUP05, and SAR92), with the potential to utilize low molecular weight-dissolved organic matter (LMW-DOM) including compatible solutes, was increased. The versatility of Gammaproteobacteria may contribute to their abundance in organic carbon-rich polynya waters, while the SAR11 clade was found to be predominant in the sea ice-covered oligotrophic ocean. SAR92 clade showed transcriptional activity for utilization of both polysaccharides and LMW-DOM; this may account for their abundance both in the peak and decline phases. Ant4D3 clade was dominant in all phases of the polynya bloom, implicating the crucial roles of this clade in LMW-DOM remineralization in the Antarctic polynyas. Conclusions Genomic reconstruction and in situ gene expression analyses revealed the unique metabolic potential of dominant bacteria of the Antarctic polynya at a finer taxonomic level. The information can be used to predict temporal community succession linked to the availability of substrates derived from the P. antarctica bloom. Global warming has resulted in compositional changes in phytoplankton from P. antarctica to diatoms, and thus, repeated parallel studies in various polynyas are required to predict global warming-related changes in carbon remineralization