Antagonistic interaction between oxygenation-linked lactate and CO2 binding to human hemoglobin

Oxygen binding to hemoglobin (Hb) depends on allosteric effectors (CO(2), lactate and protons) that may increase drastically in concentration during exercise. The effectors share common binding sites on the Hb molecules, predicting mutual interaction in their effects on Hb (de)oxygenation. We analysed the effects of lactate and CO(2), separately and in combination, on O(2) binding of purified human Hb at 37 degrees C and physiological pH and chloride values. We demonstrate pH-dependent, inhibitory interactions between lactate binding and CO(2) binding (carbamate formation); at pH 7.4, physiological CO(2) tension ( approximately 43 mm Hg) reduced lactate binding more markedly ( approximately 75%), than lactate (50 mM) inhibited carbamate formation ( approximately 25%). In contrast to previous studies on blood and Hb solutions, we moreover find that added lactate neither 'reverses' oxylabile carbamate formation (resulting in lower carbamate levels in deoxyHb than in oxyHb) nor exerts greater allosteric effects on Hb-O(2) affinity than equal increases in chloride ion concentrations.     

Inhibition of soybean urease by triketone oximes

Competitive inhibition of soybean urease by 15 triketone oximes has been studied at 36 degrees C in aqueous solution (pH 4.95). The studied oximes are supposed chelators for the nickel atom in the urease metallocenter. The inhibition constants of urea hydrolysis (K(i)) varied in the range 2.7-248 microM depending on the oxime structure. Analysis of this dependency demonstrates that the optimal inhibitor is the one containing carbonyl group in position 1 of the cycle, the ethoxyimino group and alkyl residue in the substituent in position 2, as well as the methoxycarbonyl group in position 4 of the cycle.     

Early Innate Recognition of Herpes Simplex Virus in Human Primary Macrophages Is Mediated via the MDA5/MAVS-Dependent and MDA5/MAVS/RNA Polymerase III-Independent Pathways

Innate recognition of viruses is mediated by pattern recognition receptors (PRRs) triggering expression of antiviral interferons (IFNs) and proinflammatory cytokines. In mice, Toll-like receptor 2 (TLR2) and TLR9 as well as intracellular nucleotide-sensing pathways have been shown to recognize herpes simplex virus (HSV). Here, we describe how human primary macrophages recognize early HSV infection via intracellular pathways. A number of inflammatory cytokines, IFNs, and IFN-stimulated genes were upregulated after HSV infection. We show that early recognition of HSV and induction of IFNs and inflammatory cytokines are independent of TLR2 and TLR9, since inhibition of TLR2 using TLR2 neutralizing antibodies did not affect virus-induced responses and the macrophages were unresponsive to TLR9 stimulation. Instead, HSV recognition involves intracellular recognition systems, since induction of tumor necrosis factor alpha (TNF-α) and IFNs was dependent on virus entry and replication. Importantly, expression of IFNs was strongly inhibited by small interfering RNA (siRNA) knockdown of MAVS, but this MAVS-dependent IFN induction occurred independently of the recently discovered polymerase III (Pol III)/RIG-I DNA sensing system. In contrast, induction of TNF-α was largely independent of MAVS, suggesting that induction of inflammatory cytokines during HSV infection proceeds via a novel pathway. Transfection with ODN2006, a broad inhibitor of intracellular nucleotide recognition, revealed that nucleotide-sensing systems are employed to induce both IFNs and TNF-α. Finally, using siRNA knockdown, we found that MDA5, but not RIG-I, was the primary mediator of HSV recognition. Thus, innate recognition of HSV by human primary macrophages occurs via two distinct intracellular nucleotide-sensing pathways responsible for induction of IFNs and inflammatory cytokine expression, respectively.Virus recognition is essential for activation of innate antiviral immune defense and the subsequent induction of acquired immunity. Conserved pathogen motifs, termed pathogen-associated molecular patterns (PAMPs), are recognized by pattern recognition receptors (PRRs). Virus-recognizing PRRs include Toll-like receptors (TLRs), RIG-I-like receptors (RLRs), and a number of intracellular DNA receptors. Several TLRs have been attributed roles in the recognition of virus. TLR2 and TLR4 recognize viral surface structures (3, 6, 18, 31), TLR3 recognizes double-stranded RNA (dsRNA) (2), and TLR7/8 and TLR9 function as signaling receptors for viral single-stranded RNA (ssRNA) (8, 11, 21) and CpG DNA (12, 20), respectively.Within the cell, cytoplasmic RLRs RIG-I and MDA5 both recognize accumulation of virus-derived dsRNA; in addition, RIG-I recognizes 5′-triphosphated RNA (14, 27, 39, 40). In addition to the RLRs, a number of receptors recognize foreign DNA. Presently, three DNA receptors have been identified: Z-DNA binding protein 1 (ZBP-1, or DAI) (36) and RNA polymerase III (Pol III) (1, 4) both mediate interferon (IFN) and cytokine production, whereas the AIM2 inflammasome is involved in caspase 1 activation in response to cytoplasmic dsDNA (13).Herpes simplex virus type 1 (HSV-1) and HSV-2 are two closely related human DNA viruses associated with a number of serious diseases, including orofacial infections, encephalitis, and genital infections (34). Macrophages play an important role in the first line of defense against viral infection via production of IFNs, cytokines, and chemokines that regulate the progress of the virus infection and activate and support appropriate defense mechanisms (9, 10, 24).TLR2, TLR3, and TLR9 have been identified as mediators of proinflammatory cytokine production during HSV infections. TLR2 mediates an overzealous inflammatory cytokine response following HSV-1 infection in mice, promoting mononuclear cell infiltration of the brain and development of encephalitis (18). TLR3 mediates type I and III IFN production in human fibroblasts (41). TLR9 recognizes genomic DNA from HSV-1 and HSV-2 in murine plasmacytoid dendritic cells (DCs) (17, 20) and mediates tumor necrosis factor alpha (TNF-α) and CCL5 production in murine macrophages (22). Both TLR2 and TLR9 mediate recognition of HSV and cytokine production in murine conventional DCs (35). HSV is recognized by an RLR/MAVS-dependent mechanism in murine macrophages and mouse embryonic fibroblasts (MEFs) (5, 29, 30). Recent data suggest that RNA Pol III mediates IFN production following HSV-1 infection and transfection with HSV-1 DNA in macrophage-like RAW 264.7 cells (4). Finally, murine L929 fibroblast-like cells are moderately inhibited in their ability to produce IFN after HSV-1 infection when ZBP-1 is knocked down (19, 36). Thus, several PRRs have been reported to recognize HSV-1 in murine cells and different cell lines, but the pathways responsible for sensing this virus in human primary macrophages and their impact on cytokine expression have not previously been described.In this work, we investigate the recognition pathways underlying HSV-induced cytokine and chemokine expression in human primary macrophages. We demonstrate that HSV-1-induced IFN and cytokine expression is independent of TLR2 and TLR9 but highly dependent on virus replication and intracellular nucleotide recognition systems. Specifically, induction of IFNs is dependent on MAVS and MDA5, whereas TNF-α is induced by a novel intracellular nucleotide-sensing system.     

Enzymatic hydrolysis of waste cellulose

Interstitial flow (IF) modulates both the biochemical and biophysical cues surrounding cells. It represents a very important regulating mechanism for cell/tissue function and has been commonly utilized in tissue engineering (TE). This article discusses the possible regulating mechanisms of IF on fibroblasts, the various fibroblast responses to IF, the current challenges in understanding the IF–fibroblast relationship and the application of IF for fibroblast involved TE. In particular, IF can affect fibroblast growth at both intracellular (e.g., calcium signaling, protein/proteinase secretion) and cellular (e.g., autocrine/paracrine signaling, proliferation, differentiation, alignment, adhesion, migration) levels. One major challenge for understanding IF–fibroblast interaction has been the determination of the flow and cell growth condition at microlevel especially in a three‐dimensional environment. To utilize IF and optimize the fluidic environment for TE, several influencing factors in the system including perfusate composition, flow profile, nutrient supply, signaling molecule effect, scaffold property, and fibroblast type should be considered. Biotechnol. Bioeng. 2010;107: 1–10. © 2010 Wiley Periodicals, Inc.     

The Endemic Fritillaria Species of Japan

Summary.  This paper reviews and illustrates the seven known species of Fritillaria subgenus Fritillaria that are endemic to Japan and describes a new, eighth species, Fritillaria tokushimensis Akasawa, Katayama et Naito. A key for their identification is provided.     

MICROVERTEBRATE BIOSTRATIGRAPHY OF UPPER DEVONIAN (FRASNIAN) CARBONATE ROCKS IN THE CANNING AND CARNARVON BASINS OF WESTERN AUSTRALIA

Abstract:  Shark teeth and scales from the Gneudna Formation type section, Carnarvon Basin are rare, but they represent a diverse fauna as well as being the first Frasnian chondrichthyan remains found in Western Australia. In contrast numerous shark teeth and scales have been obtained from coeval sections in the Canning Basin. Teeth referred to as Phoebodus bifurcatus, Phoebodus fastigatus, Phoebodus cf. fastigatus, Phoebodus latus , Phoebodus sp. C and Protacrodus sp. 1 are described from two Canning Basin localities: Horse Spring Range and McIntyre Knolls. The phoebodont species described here have a global distribution and can, therefore, be placed within the standard Frasnian phoebodont zonation. The shark remains from the Gneudna Formation type section include one new genus Emerikodus ektrapelus gen. et sp. nov., described along with Helodontidae indet and Elasmobranchii gen. et sp. indet. It is proposed that the faunal differences observed between the localities are a result of environmental differences. In addition to shark remains, scales from the thelodont Australolepis seddoni were also recovered from each locality. The well-dated Zone 6–10 conodont faunas at Horse Spring constrain the range of A. seddoni with which they occur, and importantly indicate that the Gneudna Formation type section is wholly Frasnian.