Search

Agaricus bisporus is the model fungus for the adaptation, persistence, and growth in the humic-rich leaf-litter environment. Aside from its ecological role, A. bisporus has been an important component of the human diet for over 200 y and worldwide cultivation of the button mushroom forms a multibillion dollar industry. We present two A. bisporus genomes, their gene repertoires and transcript profiles on compost and during mushroom formation. The genomes encode a full repertoire of polysaccharide-degrading enzymes similar to that of wood-decayers. Comparative transcriptomics of mycelium grown on defined medium, casing-soil, and compost revealed genes encoding enzymes involved in xylan, cellulose, pectin, and protein degradation are more highly expressed in compost. The striking expansion of heme-thiolate peroxidases and etherases is distinctive from Agaricomycotina wood-decayers and suggests a broad attack on decaying lignin and related metabolites found in humic acid-rich environment. Similarly, up-regulation of these genes together with a lignolytic manganese peroxidase, multiple copper radical oxidases, and cytochrome P450s is consistent with challenges posed by complex humic-rich substrates. The gene repertoire and expression of hydrolytic enzymes in A. bisporus is substantially different from the taxonomically related ectomycorrhizal symbiont Laccaria bicolor. A common promoter motif was also identified in genes very highly expressed in humic-rich substrates. These observations reveal genetic and enzymatic mechanisms governing adaptation to the humic-rich ecological niche formed during plant degradation, further defining the critical role such fungi contribute to soil structure and carbon sequestration in terrestrial ecosystems. Genome sequence will expedite mushroom breeding for improved agronomic characteristics.

Research illustrates the interaction of carbon monoxide with the dinuclear center of reduced bacterrial nitric oxide reductase. Results reveal that the ligand binds to iron(II) heme b(sub)3 forming a stable complex, which suggests differences in the organization of this active site from other heme-copper oxidase superfamily.

Abstract Introduction Inflammation contributes to cardiovascular disease and is exacerbated with increased adiposity, particularly omental adiposity; however, the role of epicardial fat is poorly understood. Methods For these studies the expression of inflammatory markers was assessed in epicardial fat biopsies from coronary artery bypass grafting (CABG) patients using quantitative RT-PCR. Further, the effects of chronic medications, including statins, as well as peri-operative glucose, insulin and potassium infusion, on gene expression were also assessed. Circulating resistin, CRP, adiponectin and leptin levels were determined to assess inflammation. Results The expression of adiponectin, resistin and other adipocytokine mRNAs were comparable to that in omental fat. Epicardial CD45 expression was significantly higher than control depots (p < 0.01) indicating significant infiltration of macrophages. Statin treated patients showed significantly lower epicardial expression of IL-6 mRNA, in comparison with the control abdominal depots (p < 0.001). The serum profile of CABG patients showed significantly higher levels of both CRP (control: 1.28 ± 1.57 μg/mL vs CABG: 9.11 ± 15.7 μg/mL; p < 0.001) and resistin (control: 10.53 ± 0.81 ng/mL vs CABG: 16.8 ± 1.69 ng/mL; p < 0.01) and significantly lower levels of adiponectin (control: 29.1 ± 14.8 μg/mL vs CABG: 11.9 ± 6.0 μg/mL; p < 0.05) when compared to BMI matched controls. Conclusion Epicardial and omental fat exhibit a broadly comparable pathogenic mRNA profile, this may arise in part from macrophage infiltration into the epicardial fat. This study highlights that chronic inflammation occurs locally as well as systemically potentially contributing further to the pathogenesis of coronary artery disease.

Adipose tissue (AT) distribution has significant impact on disease, with central abdominal fat increasing the risk of T2DM and CVD compared with gluteo-femoral (thigh) fat, however limited studies to date have addressed the site-specific nature of human epicardial AT in relation to thigh fat. Our previous studies have implicated epicardial AT as a source of inflammatory cytokines which may influence myocardial function, due to its location. This study examined, in matched paired epicardial and thigh AT from patients undergoing coronary artery bypass grafting (CABG), the intrinsic nature of epicardial and thigh AT during inflammation, mediators of the innate immune pathway toll like receptors (TLR) 2 & 4, NFκB & JNK as potential key mediators of adipocytokine production, CD68 gene expression (macrophage marker, to investigate the role of macrophages in epicardial AT) and whether elevated systemic endotoxin levels may initiate the innate immune response. Fasted serum was taken from CABG subjects (Age:63.8±8.4yrs, BMI:27.8±3.5kg/m², n=72) and non-CAD subjects (Age:61.8±8.0yrs, BMI:27.9±3.3kg/m², n=60). A sub-cohort of paired epicardial and gluteo-femoral AT was obtained from CABG subjects (Age:66.7±6.7yrs, BMI:28.4±3.6 kg/m⊃2, n=16). Endotoxin was measured by LAL assay. In epicardial AT, gene expression data showed associations between CD68 with TLR2 (r=0.94, p<0.001), TLR4 (r=0.95, p<0.001) and TNFα (r=0.81, p<0.001). NFκB and the IKK protein expression was higher in epicardial AT compared with thigh (NF κB p=0.06, IKKβ p=0.01, IKKγp=0.001) as well as JNK expression (p<0.01). Lastly, serum endotoxin was raised in CABG patients compared with controls (p<0.05). In brief epicardial AT showed increased NF κB, IKKβ and JNK levels compared with matched thigh AT; suggesting a depot-specific inflammatory response. Thus enhanced activation of the NF κB and JNK pathways in the epicardial depot may arise through increased simultaneous activation of macrophages and adipocytes. Also such an inflammatory response in AT may arise due to gut-derived endotoxin levels which were increased in CABG patients. In conclusion, these studies show epicardial AT as a source of inflammatory cytokines through NFκB and other key inflammatory pathways highlighting the significance of macrophages in epicardial AT. [ABSTRACT FROM AUTHOR]

Central obesity is strongly associated with sub-clinical inflammation, insulin resistance (IR) and type 2 diabetes mellitus (T2DM), but the intracellular mechanisms involved in the pathogenesis of central obesity remain unclear. Recent studies have implicated NF κB and c-Jun N terminal kinase (JNK) as central molecules linking insulin action and inflammation in mice. Our study aimed to investigate (1) the central inflammatory intracellular signaling pathways involving NF κB and JNK activation in abdominal subcutaneous (AbdSc) and omental (Ore) human adipose tissue, (2) the influence of adiposity and diabetic status on the activation of the NF κB and its key intermediates and JNK within these AT depots and (3) the effects of TNFα, a known mediator of inflammation in mice, on NF κB and JNK activity in human AbdSc adipocytes. Our data showed that ex vivo IKKβ, IKKγ, I κBα and I κB α -P protein expression was increased in Om AT compared with AbdSc AT (p<0.01). The ratio of active NF κB to total NF κB expression (NF κB ratio) was upregulated in Om AT compared with AbdSc in both lean and obese subjects (p<0.05). Whilst, phosphospecific JNK1 was increased 5.8 fold in the AbdSc depot, (p<0.01), compared with Om AT. In in vitro TNF α treated AbdSc adipocytes NF κB activity increased over time (2-48 hr, p<0.05), however JNK activity remained unchanged. In conclusion, these findings suggest distinct inflammatory signaling pathways with increased NF κB in human Om AT and JNK in AbdSc AT. In addition, NF κB was influenced by obesity and diabetic status, whilst TNF α treated AbdSc lead to activation of NF κB and not JNK. Consequently, NF κB appears to play a more central role in inflammatory mediated metabolic disease than JNK, highlighting NF κB as a potential key target for therapeutic intervention. [ABSTRACT FROM AUTHOR]