Action mechanism and structural requirements of the antimicrobial peptides, gaegurins

AbstractGaegurins (GGNs) are a family of cationic, α-helical, antimicrobial peptides that were isolated from a Korean frog, Glandirana emeljanovi (formerly classified as Rana rugosa) and represent one of the structurally well-characterized groups. Among six gaegurins, gaegurin 4 (renamed herein esculentin-2EM), gaegurin 5 (brevinin-1EMa), and gaegurin 6 (brevinin-1EMb) have been investigated comprehensively in terms of structure–activity relationships. In this paper, we first suggest renaming of gaegurins according to a recently raised rule of systematic nomenclature. Then, the current understanding of gaegurins is reviewed by summarizing their structure–activity relationships. In particular competing arguments on gaegurins are synthetically inspected. Finally their action mechanism and structural requirements will be discussed

Effects of Expectation-Disconfirmation regarding the Role of Government on Trust in Government and the Moderating Effect of Citizen Participation

This study draws on expectation-disconfirmation theory to explore differences between what is expected of the government and perceptions of what the government in fact does and to determine the influence of these differences on trust in government. Confirming the applicability of contact theory, this study also reveals the moderating effect of citizen participation. The results show that the more citizens expectations regarding the role of government are not met, the less trust they have in government. The relation between these two variables is consistently observed, regardless of ways of measuring trust in government. However, the negative relation between expectation-disconfirmation and trust in government was moderated by citizens political participation.This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2017S1A3A2066084)

Modeling the plastic deformation of crystals with thin precipitates

AbstractPrecipitates, present in most commercial alloys, can have a strong influence on strength and hardening behavior of a single crystal. The effect of thin precipitates on the anisotropy of initial slip resistance and hardening behavior of crystals is modeled in this article. For the convenience of the computational derivation and implementation, the material formulation is given in the unrotated intermediate configuration mapped by the plastic part of the deformation gradient. Material descriptions for the considered two phased aggregates consisting in lattice hardening as well as isotropic hardening and kinematic hardening are suggested. The corresponding elastic–plastic rate-independent algorithmic treatment is derived and numerical simulations of various loading cases are presented to discuss and assess the performance of the suggested model and its rate-independent algorithmic treatment

Direct numerical simulation of a 30R long turbulent pipe flow at Re=3008

A direct numerical simulation of a turbulent pipe flow at a high Reynolds number of Re-tau = 3008 over a long axial domain length (30R) was performed. The stream-wise mean velocity followed the power law in the overlap region (y(+) = 90-300; y/R = 0.03-0.1) based on the power law indicator function. The scale separation of the Reynolds shear stresses into two components of small-and large-scale motions (LSMs) revealed that the LSMs in the outer region played an important role in constructing the constant-stress layer and the mean velocity. In the pre-multiplied energy spectra of the streamwise velocity fluctuations, the bimodal distribution was observed at both short and long wavelengths. The k(x)(-1) region associated with the attached eddies appeared in lambda(x)/R = 2-5 and lambda(x)/y = 18-160 at y(+) = 90-300, where the power law was established in the same region. The k(z)(-1) region also appeared in lambda(z)/R = 0.3-0.6 at y(+) = 3 and 150. Linear growth of small-scale energy to large-scale energy induced the k(x)(-1) region at high Reynolds numbers, resulting in a large population of the LSMs. This result supported the origin of very-large-scale motions in the pseudo-streamwise alignment of the LSMs. In the pre-multiplied energy spectra of the Reynolds shear stress, the bimodal distribution was observed without the k(x)(-1) region.open

TLR3 signaling is either protective or pathogenic for the development of Theiler's virus-induced demyelinating disease depending on the time of viral infection

Background: We have previously shown that toll-like receptor 3 (TLR3)-mediated signaling plays an important role in the induction of innate cytokine responses to Theiler\u27s murine encephalomyelitis virus (TMEV) infection. In addition, cytokine levels produced after TMEV infection are significantly higher in the glial cells of susceptible SJL mice compared to those of resistant C57BL/6 mice. However, it is not known whether TLR3-mediated signaling plays a protective or pathogenic role in the development of demyelinating disease. Methods: SJL/J and B6; 129S-Tlr3(tm1Flv)/J (TLR3KO-B6) mice, and TLR3KO-SJL mice that TLR3KO-B6 mice were backcrossed to SJL/J mice for 6 generations were infected with Theiler\u27s murine encephalomyelitis virus (2 x 10(5) PFU) with or without treatment with 50 mu g of poly IC. Cytokine production and immune responses in the CNS and periphery of infected mice were analyzed. Results: We investigated the role of TLR3-mediated signaling in the protection and pathogenesis of TMEV-induced demyelinating disease. TLR3KO-B6 mice did not develop demyelinating disease although they displayed elevated viral loads in the CNS. However, TLR3KO-SJL mice displayed increased viral loads and cellular infiltration in the CNS, accompanied by exacerbated development of demyelinating disease, compared to the normal littermate mice. Late, but not early, anti-viral CD4(+) and CD8(+) T cell responses in the CNS were compromised in TLR3KO-SJL mice. However, activation of TLR3 with poly IC prior to viral infection also exacerbated disease development, whereas such activation after viral infection restrained disease development. Activation of TLR3 signaling prior to viral infection hindered the induction of protective IFN-gamma-producing CD4(+) and CD8(+) T cell populations. In contrast, activation of these signals after viral infection improved the induction of IFN-gamma-producing CD4(+) and CD8(+) T cells. In addition, poly IC-pretreated mice displayed elevated PDL-1 and regulatory FoxP3(+) CD4+ T cells in the CNS, while poly IC-post-treated mice expressed reduced levels of PDL-1 and FoxP3(+) CD4(+) T cells. Conclusions: These results suggest that TLR3-mediated signaling during viral infection protects against demyelinating disease by reducing the viral load and modulating immune responses. In contrast, premature activation of TLR3 signal transduction prior to viral infection leads to pathogenesis via over-activation of the pathogenic immune response

Ultraviolet-c haematogenous oxidation therapy of lipopolysaccharide-induced endotoxemia in a rabbit model: A biochemical study

Systemic inflammatory reaction – due to severe response to toxins of infection associated with immune inhibition – leads to multi-organ dysfunctions and high mortality. Ultraviolet (UV) blood is used for its therapeutic effects when moving across the cells. This study aims to evaluate the impact of UV-c Haematogenous Oxidation Therapy (HOT) in Lipopolysaccharide (LPS)-induced endotoxemia of rabbit model. A total of 40 rabbits randomly divided into four groups, including normal control (NC). LPS and LPS+UV-c HOT groups received 0.1 mg/kg LPS toxin of E. coli, UV-c HOT and LPS+UV-c HOT groups subjected to UV-c HOT treatments once weekly for five times. Blood collected, perfused with oxygen, UV-c directly irradiated into blood, and then auto-transfused. Rabbits were sacrificed after five weeks; blood and serum were collected for analysis. The survival rate, liver, kidney, lipid profile, and blood ions were assessed in treated rabbits. Mortality was 40% in the LPS group, while other groups showed no death. UV-c HOT enhanced critical pH, base deficit, blood gases, hypomagnesemia, hyperlactatemia, and concurrent acidosis. Besides, TNF-α, nitrite, and nitrate were suppressed in response to UV-c HOT. Moreover, UV-c HOT reduced liver and kidney enzymes, improved lipid metabolism, and ameliorated electrolytes homeostasis. Despite that, UV-c HOT performance in ICU for human and animal endotoxemic or septic patients should be evaluated and considered

In vivo and in vitro studies of Mgs1 suggest a link between genome instability and Okazaki fragment processing

The non-essential MGS1 gene of Saccharomyces cerevisiae is highly conserved in eukaryotes and encodes an enzyme containing both DNA-dependent ATPase and DNA annealing activities. MGS1 appears to function in post-replicational repair processes that contribute to genome stability. In this study, we identified MGS1 as a multicopy suppressor of the temperature-sensitive dna2Δ405N mutation, a DNA2 allele lacking the N-terminal 405 amino acid residues. Mgs1 stimulates the structure-specific nuclease activity of Rad27 (yeast Fen1 or yFen1) in an ATP-dependent manner. ATP binding but not hydrolysis was sufficient for the stimulatory effect of Mgs1, since non-hydrolyzable ATP analogs are as effective as ATP. Suppression of the temperature-sensitive growth defect of dna2Δ405N required the presence of a functional copy of RAD27, indicating that Mgs1 suppressed the dna2Δ405N mutation by increasing the activity of yFen1 (Rad27) in vivo. Our results provide in vivo and in vitro evidence that Mgs1 is involved in Okazaki fragment processing by modulating Fen1 activity. The data presented raise the possibility that the absence of MGS1 may impair the processing of Okazaki fragments, leading to genomic instability

Ultraviolet-C haematogenous oxidation therapy of lipopolysaccharide-induced endotoxemia in a rabbit model: A biochemical study

445-454Systemic inflammatory reaction – due to severe response to toxins of infection associated with immune inhibition – leads to multi-organ dysfunctions and high mortality. Ultraviolet (UV) blood is used for its therapeutic effects when moving across the cells. This study aims to evaluate the impact of UV-C Haematogenous Oxidation Therapy (HOT) in Lipopolysaccharide (LPS)-induced endotoxemia of rabbit model. A total of 40 rabbits randomly divided into four groups, including normal control (NC). LPS and LPS+UV-C HOT groups received 0.1 mg/kg LPS toxin of E. coli, UV-C HOT and LPS+UV-C HOT groups subjected to UV-C HOT treatments once weekly for five times. Blood collected, perfused with oxygen, UV-C directly irradiated into blood, and then auto-transfused. Rabbits were sacrificed after five weeks; blood and serum were collected for analysis. The survival rate, liver, kidney, lipid profile, and blood ions were assessed in treated rabbits. Mortality was 40% in the LPS group, while other groups showed no death. UV-C HOT enhanced critical pH, base deficit, blood gases, hypomagnesemia, hyperlactatemia, and concurrent acidosis. Besides, TNF-α, nitrite, and nitrate were suppressed in response to UV-C HOT. Moreover, UV-C HOT reduced liver and kidney enzymes, improved lipid metabolism, and ameliorated electrolytes homeostasis. Despite that, UV-C HOT performance in ICU for human and animal endotoxemic or septic patients should be evaluated and considered

Synergistic effect of acetyl xylan esterase on xylanase reaction originated from Ochrovirga pacifica

Acetyl xylan esterase plays an important role in complete enzymatic hydrolysis of lignocellulosic materials into fermentable sugars. It hydrolyzes ester linkages of acetic acid in xylan polysaccharide and supports to enhance the activity of xylanase. This study was conducted to recognize and overexpress the acetyl xylan esterase gene found from Ochrovirga pacifica strain S85 which was isolated from Chuuk state, Micronesia. The genome sequence was analyzed with genome sequencer-FLX and acetyl xylan esterase gene (Axe) was detected. The gene had an open reading frame of 864 bp encoding a polypeptide of 287 amino acids. Theoretical molecular mass and isoelectric point (pI) were 32 kDa and 5.9, respectively. The deduced amino acid sequence of the Axe showed 35.1% similarity with both endo-1,4-β-xylanase B from Robiginitalea biformata HTCC2501. The mature protein displayed the catalytic residues classically found in enzymes belonged to GH16 family. Axe was cloned into pET11a vector and recombinant protein was expressed in E. coli BL21 (DE3), purified by nickel affinity chromatography and its purity was visualized on SDS-PAGE. Commercial xylanase activity was tested after treatment of recombinant acetyl xylan esterase (rAXE) to birchwood xylan substrate. The xylanase activity of rAXE treated sample was about 2 times higher than xylanase only treated sample. Please click Additional Files below to see the full abstract