Unveiling the Biochar-Respiratory Growth of Methanosarcina acetivorans Involving Extracellular Polymeric Substances.

Biochar can be applied to diverse natural and engineered anaerobic systems. Biochar plays biogeochemical roles during its production, storage, and environmental dynamics, one of which is related to the global methane flux governed by methanotrophs and methanogens. Our understanding of relevant mechanisms is currently limited to the roles of biochar in methanotrophic growth, but less is known about the roles of biochar in methanogenic growth. Here, we demonstrated that biochar enhanced the methanogenic growth of a model methanogen, Methanosarcina acetivorans, and the role of biochar as an electron acceptor during methanogenic growth was confirmed, which is referred to as biochar-respiratory growth. The biochar-respiratory growth of M. acetivorans promoted the secretion of extracellular polymeric substances (EPS) with augmented electron transfer capabilities, and the removal of EPS significantly attenuated extracellular electron transfer. Identification and quantification of prosthetic cofactors for EPS suggest an important role of flavin and F420 in extracellular electron transfer. Transcriptomic analysis provided additional insights into the biochar-respiratory growth of M. acetivorans, showing that there was a positive response in transcriptional regulation to the favorable growth environment provided by biochar, which stimulated global methanogenesis. Our results shed more light on the in situ roles of biochar in the ecophysiology of methanogens in diverse anaerobic environments.

Characterizing the free-energy landscapes of DNA origamis.

We show how coarse-grained modelling combined with umbrella sampling using distance-based order parameters can be applied to compute the free-energy landscapes associated with mechanical deformations of large DNA nanostructures. We illustrate this approach for the strong bending of DNA nanotubes and the potentially bistable landscape of twisted DNA origami sheets. The homogeneous bending of the DNA nanotubes is well described by the worm-like chain model; for more extreme bending the nanotubes reversibly buckle with the bending deformations localized at one or two "kinks". For a twisted one-layer DNA origami, the twist is coupled to the bending of the sheet giving rise to a free-energy landscape that has two nearly-degenerate minima that have opposite curvatures. By contrast, for a two-layer origami, the increased stiffness with respect to bending leads to a landscape with a single free-energy minimum that has a saddle-like geometry. The ability to compute such landscapes is likely to be particularly useful for DNA mechanotechnology and for understanding stress accumulation during the self-assembly of origamis into higher-order structures.

Enantioselective hydrogenation of cyclic tetrasubstituted-olefinic dehydroamino acid derivatives.

An efficient asymmetric hydrogenation of cyclic tetrasubstituted-olefinic dehydroamino acid derivatives has been achieved with a Rh-ArcPhos catalyst, affording a series of α-acylamino-ß-alkyl tetrahydropyranones with two contiguous chiral centers in up to 96% ee and 1000 TON.

Chitinase 3-like 1 suppresses injury and promotes fibroproliferative responses in Mammalian lung fibrosis.

Epithelial injury, alternative macrophage accumulation, and fibroproliferation coexist in the lungs of patients with idiopathic pulmonary fibrosis (IPF). Chitinase 3-like 1 (CHI3L1) is a prototypic chitinase-like protein that has been retained over species and evolutionary time. However, the regulation of CHI3L1 in IPF and its ability to regulate injury and/or fibroproliferative repair have not been fully defined. We demonstrated that CHI3L1 levels were elevated in patients with IPF. High levels of CHI3L1 are associated with progression--as defined by lung transplantation or death--and with scavenger receptor-expressing circulating monocytes in an ambulatory IPF population. In preterminal acute exacerbations of IPF, CHI3L1 levels were reduced and associated with increased levels of apoptosis. We also demonstrated that in bleomycin-treated mice, CHI3L1 expression was acutely and transiently decreased during the injury phase and returned toward and eventually exceeded baseline levels during the fibrotic phase. In this model, CHI3L1 played a protective role in injury by ameliorating inflammation and cell death, and a profibrotic role in the repair phase by augmenting alternative macrophage activation, fibroblast proliferation, and matrix deposition. Using three-dimensional culture system of a human fibroblast cell line, we found that CHI3L1 is sufficient to induce low grade myofibroblast transformation. In combination, these studies demonstrate that CHI3L1 is stimulated in IPF, where it represents an attempt to diminish injury and induce repair. They also demonstrate that high levels of CHI3L1 are associated with disease progression in ambulatory patients and that a failure of the CHI3L1 antiapoptotic response might contribute to preterminal disease exacerbations.

Lung vascular endothelial growth factor expression induces local myeloid dendritic cell activation.

We previously demonstrated that vascular endothelial growth factor (VEGF) expression in the murine lung increases local CD11c+MHCII+ DC number and activation. In this study, employing a multicolor flow cytometry, we report increases in both myeloid (mDC) and plasmacytoid (pDC) DC in the lungs of VEGF transgenic (tg) compared to WT mice. Lung pDC from VEGF tg mice exhibited higher levels of activation with increased expression of MHCII and costimulatory molecules. As VEGF tg mice display an asthma-like phenotype and lung mDC play a critical role in asthmatic setting, studies were undertaken to further characterize murine lung mDC. Evaluations of sorted mDC from VEGF tg lungs demonstrated a selective upregulation of cathepsin K, MMP-8, -9, -12, and -14, and chemokine receptors as compared to those obtained from WT control mice. They also had increased VEGFR2 but downregulated VEGFR1 expression. Analysis of chemokine and regulatory cytokine expression in these cells showed an upregulation of macrophage chemotactic protein-3 (MCP-3), thymus-expressed chemokine (TECK), secondary lymphoid organ chemokine (SLC), macrophage-derived chemokine (MDC), IL-1beta, IL-6, IL-12 and IL-13. The antigen (Ag) OVA-FITC uptake by lung DC and the migration of Ag-loaded DC to local lymph nodes were significantly increased in VEGF tg mice compared to WT mice. Thus, VEGF may predispose the lung to inflammation and/or repair by activating local DC. It regulates lung mDC expression of innate immunity effector molecules. The data presented here demonstrate how lung VEGF expression functionally affects local mDC for the transition from the innate response to a Th2-type inflammatory response.

Endogenous IL-11 signaling is essential in Th2- and IL-13-induced inflammation and mucus production.

IL-11 and IL-11 receptor (R)alpha are induced by Th2 cytokines. However, the role(s) of endogenous IL-11 in antigen-induced Th2 inflammation has not been fully defined. We hypothesized that IL-11, signaling via IL-11Ralpha, plays an important role in aeroallergen-induced Th2 inflammation and mucus metaplasia. To test this hypothesis, we compared the responses induced by the aeroallergen ovalbumin (OVA) in wild-type (WT) and IL-11Ralpha-null mutant mice. We also generated and defined the effects of an antagonistic IL-11 mutein on pulmonary Th2 responses. Increased levels of IgE, eosinophilic tissue and bronchoalveolar lavage (BAL) inflammation, IL-13 production, and increased mucus production and secretion were noted in OVA-sensitized and -challenged WT mice. These responses were at least partially IL-11 dependent because each was decreased in mice with null mutations of IL-11Ralpha. Importantly, the administration of the IL-11 mutein to OVA-sensitized mice before aerosol antigen challenge also caused a significant decrease in OVA-induced inflammation, mucus responses, and IL-13 production. Intraperitoneal administration of the mutein to lung-specific IL-13-overexpressing transgenic mice also reduced BAL inflammation and airway mucus elaboration. These studies demonstrate that endogenous IL-11R signaling plays an important role in antigen-induced sensitization, eosinophilic inflammation, and airway mucus production. They also demonstrate that Th2 and IL-13 responses can be regulated by interventions that manipulate IL-11 signaling in the murine lung.

Type 1 corticotropin-releasing factor receptors in the ventromedial hypothalamus promote hypoglycemia-induced hormonal counterregulation.

Type 2 corticotropin-releasing factor (CRF) receptors (CRFR2) within the ventromedial hypothalamus (VMH), a key glucose-sensing region, play a major role in regulating the hormonal counterregulatory responses (CRRs) to acute hypoglycemia. The VMH expresses both subtypes of CRF receptors, CRFR1 and CRFR2. The objective of this study was to examine the role of the CRFR1 receptor in the VMH in the regulation of the CRR to acute hypoglycemia. To compare the hormonal CRR to hypoglycemia, awake and unrestrained Sprague-Dawley rats were bilaterally microinjected to the VMH with either 1) aECF, 2) CRF (1 pmol/side), 3) CRFR1 antagonist Antalarmin (500 pmol/side), or 4) CRF + Antalarmin prior to undergoing a hyperinsulinemic hypoglycemic (2.8 mM) clamp. A second series of studies also incorporated an infusion of [(3)H]glucose to allow the calculation of glucose dynamics. In addition the effect of CRFR1 antagonism in the paraventricular nucleus (PVN) was studied. Activation of VMH CRFR1 increased, whereas inhibition of CRFR1 suppressed hypoglycemia-induced CRRs. Inhibition of VMH CRFR1 also increased peripheral glucose utilization and reduced endogenous glucose production during hypoglycemia, whereas VMH CRF reduced peripheral glucose utilization. In contrast CRFR1 inhibition in the PVN blunted corticosterone but not epinephrine or glucagon CRR to hypoglycemia. In contrast to CRFR2 activation, CRFR1 activation within the VMH amplifies CRRs to acute hypoglycemia. The balance between these two opposing CRFRs in this key glucose-sensing region may play an important role in determining the magnitude of CRRs to acute hypoglycemia.