High-heat Effects on the Physical and Chemical Properties of Soil Organic Matter and Its Water-soluble Components in Japan's Forests: A Comprehensive Approach Using Multiple Analytical Methods.

Wildfires that expose the soil organic layer to high heat levels can alter soil organic matter (SOM), which includes water-soluble organic matter (WSOM) components. Various evaluation methods were used to characterize and quantify the effects of high heat levels on SOM and WSOM, including ion chromatography, thermogravimetry-differential thermal analysis (TG-DTA), colorimetry, elemental analysis, pyrolysis-gas chromatography-mass spectrometry using tetramethylammonium hydroxide (TMAH-py-GC/MS), total organic carbon (TOC) analysis, three-dimensional excitation-emission matrix (3DEEM) spectroscopy, and high-performance size-exclusion chromatography. In this study, we applied each of these evaluation methods using soil samples that were collected from broadleaf, coniferous, and bamboo forests and peatland in Japan and exposed to different initial high heat levels. Based on the TG-DTA results, the remaining mass in select soil samples markedly decreased when reheated to approximately 200°C. Comparatively, the TMAH-py-GC/MS results indicated a drastic change in SOM composition and the production of low molecular organic components (

Angiopoietin Like Protein 2 (ANGPTL2) Promotes Adipose Tissue Macrophage and T lymphocyte Accumulation and Leads to Insulin Resistance.

OBJECTIVES: Angiopoietin-like protein 2 (ANGPTL2), a recently identified pro-inflammatory cytokine, is mainly secreted from the adipose tissue. This study aimed to explore the role of ANGPTL2 in adipose tissue inflammation and macrophage activation in a mouse model of diabetes. METHODOLOGY/PRINCIPAL FINDINGS: Adenovirus mediated lacZ (Ad-LacZ) or human ANGPTL2 (Ad-ANGPTL2) was delivered via tail vein in diabetic db/db mice. Ad-ANGPTL2 treatment for 2 weeks impaired both glucose tolerance and insulin sensitivity as compared to Ad-LacZ treatment. Ad-ANGPTL2 treatment significantly induced pro-inflammatory gene expression in white adipose tissue. We also isolated stromal vascular fraction from epididymal fat pad and analyzed adipose tissue macrophage and T lymphocyte populations by flow cytometry. Ad-ANGPTL2 treated mice had more adipose tissue macrophages (F4/80+CD11b+) and a larger M1 macrophage subpopulation (F4/80+CD11b+CD11c+). Moreover, Ad-ANGPTL2 treatment increased a CD8-positive T cell population in adipose tissue, which preceded increased macrophage accumulation. Consistent with our in vivo results, recombinant human ANGPTL2 protein treatment increased mRNA levels of pro-inflammatory gene products and production of TNF-α protein in the human macrophage-like cell line THP-1. Furthermore, Ad-ANGPTL2 treatment induced lipid accumulation and increased fatty acid synthesis, lipid metabolism related gene expression in mouse liver. CONCLUSION: ANGPTL2 treatment promotes macrophage accumulation and activation. These results suggest potential mechanisms for insulin resistance.

Low dependency of retrotransposition on the ORF1 protein of the zebrafish LINE, ZfL2-1.

The zebrafish long interspersed element (LINE), ZfL2-1, which belongs to the L2 clade, contains two open reading frames, ORF1 and ORF2. ORF1 encodes a protein containing a coiled-coil motif and an esterase domain, whereas ORF2 encodes a protein containing an endonuclease and a reverse transcriptase domain. To elucidate the functional significance of ORF1 in retrotransposition, we constructed many variants of ZfL2-1 and examined their retrotransposition ability. We concluded: 1) the ORF1 protein is not essential for ZfL2-1 retrotransposition in cultured cells; 2) the translation of ORF1 is required for the translation of ORF2; and 3) ORF2 translation probably occurs via suppression of the ORF1 stop codon, the efficiency of which is influenced by the context of the sequence juxtaposed to the 3' side of the stop codon. These results offer a new perspective on the evolution of the L2 clade LINEs.

Pitavastatin increases ABCA1 expression by dual mechanisms: SREBP2-driven transcriptional activation and PPARα-dependent protein stabilization but without activating LXR in rat hepatoma McARH7777 cells.

Hepatic ATP-binding cassette transporter A1 (ABCA1) plays a key role in high-density lipoprotein (HDL) production by apolipoprotein A-I (ApoA-I) lipidation. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, statins, increase ABCA1 mRNA levels in hepatoma cell lines, but their mechanism of action is not yet clear. We investigated how statins increase ABCA1 in rat hepatoma McARH7777 cells. Pitavastatin, atorvastatin, and simvastatin increased total ABCA1 mRNA levels, whereas pravastatin had no effect. Pitavastatin also increased ABCA1 protein. Hepatic ABCA1 expression in rats is regulated by both liver X receptor (LXR) and sterol regulatory element-binding protein (SREBP2) pathways. Pitavastatin repressed peripheral type ABCA1 mRNA levels and its LXR-driven promoter, but activated the liver-type SREBP-driven promoter, and eventually increased total ABCA1 mRNA expression. Furthermore, pitavastatin increased peroxisome proliferator-activated receptor α (PPARα) and its downstream gene expression. Knockdown of PPARα attenuated the increase in ABCA1 protein, indicating that pitavastatin increased ABCA1 protein via PPARα activation, although it repressed LXR activation. Furthermore, the degradation of ABCA1 protein was retarded in pitavastatin-treated cells. These data suggest that pitavastatin increases ABCA1 protein expression by dual mechanisms: SREBP2-mediated mRNA transcription and PPARα-mediated ABCA1 protein stabilization, but not by the PPAR-LXR-ABCA1 pathway. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10241FP].

Isolation and characterization of retrotransposition-competent LINEs from zebrafish.

Long interspersed elements (LINEs) are a type of retroposon and are widely distributed in most eukaryotic genomes. LINEs are classified into two groups, the stringent type and relaxed type, based on the recognition of the 3' tail of their own RNA by reverse transcriptase (RT) during retrotransposition. Although most LINEs are thought to belong to the stringent type, retrotransposition studies of the stringent type LINEs are relatively limited compared with those of the relaxed type. We have now isolated two retrotransposition-competent LINEs (ZfL2-1 and ZfL2-2) from the zebrafish genome. Both ZfL2-1 and ZfL2-2 are members of the L2 clade; ZfL2-1 encodes two open reading frames (ORFs) and ZfL2-2 encodes one ORF, and each of the ORFs is required for retrotransposition. Using a retrotransposition assay in HeLa cells, we established that both ZfL2-1 and Zfl2-2 belong to the stringent type. We also demonstrated that an esterase (ES) domain encoded by ZfL2-1 ORF1 strongly enhances its own retrotransposition. The ES domain is encoded only in ORF1 of LINEs classified in the CR1 and L2 clades, although its function or significance in retrotransposition has not been elucidated. Thus, this is the first experimental evidence that the ES domain has an enhancing function during retrotransposition. These zebrafish LINEs will be useful for determining the function of ORF1 and the retrotransposition mechanism of stringent-type LINEs.