New Lignans from the Flower of Forsythia koreana and Their Suppression Effect on VCAM‐1 Expression in MOVAS Cells

Six lignans including two new lignans were obtained as the principal components of the Forsythia koreana flowers via silica gel (SiO₂), octadecyl SiO₂ (ODS) as well as Sephadex LH‐20 column chromatography. In addition to two new lignans, named koreanaside A ((7R,8S,7′R,8′S)‐7,7′‐diepoxy‐5′‐hydroxy‐3,3′‐dimethoxylignan 4‐O‐β‐d ‐glucopyranoside) and koreanaside B ((7R,8S,7′S,8′R)‐7,9′‐epoxy‐9,5′,7′‐trihydroxy‐3,3′‐dimethoxylignan 4‐O‐β‐d ‐glucopyranoside), four known lignans were identified to be (+)‐phylligenin, (?)‐epipinoresinol, pinoresinol, and tinosposide A. The structures and absolute configurations of koreanasides A and B were established by means of analysis of spectroscopic data (NMR, IR, FAB‐MS, and CD), whereas the structures of known lignans were identified by comparison their NMR and MS values with those in the reported literature. Their chemical structures including configuration were established by means of analysis of spectroscopic data (NMR, IR, FAB‐MS, and CD) but also comparison of their NMR and MS values with those in the reported literature. This is the first article for isolation of six lignans of F. koreana flowers. Koreanasides A and B showed high radical scavenging activity with oxygen radical absorbance capacity (ORAC) values of 0.97 ± 0.01 and 1.02 ± 0.01, respectively. Koreanaside A also prohibited expressing VCAM‐1 in MOVAS cells with 80.5% at 25 mg/mL.     

UBCG: Up-to-date bacterial core gene set and pipeline for phylogenomic tree reconstruction

Genome-based phylogeny plays a central role in the future taxonomy and phylogenetics of Bacteria and Archaea by replacing 16S rRNA gene phylogeny. The concatenated core gene alignments are frequently used for such a purpose. The bacterial core genes are defined as single-copy, homologous genes that are present in most of the known bacterial species. There have been several studies describing such a gene set, but the number of species considered was rather small. Here we present the up-to-date bacterial core gene set, named UBCG, and software suites to accommodate necessary steps to generate and evaluate phylogenetic trees. The method was successfully used to infer phylogenomic relationship of Escherichia and related taxa and can be used for the set of genomes at any taxonomic ranks of Bacteria. The UBCG pipeline and file viewer are freely available at https://www.ezbiocloud.net/tools/ubcg and https://www.ezbiocloud.net/tools/ubcg_viewer, respectively.     

Temperature-dependent development and oviposition models of Ramulus irregulariterdentatus (Phasmida: Phasmatidae)

Public interest in Ramulus irregulariterdentatus as a pet insect in Korea is increasing, although it is also considered as a potential forest insect pest. The objective of this study was to construct development and oviposition models of R. irregulariterdentatus. Development rates were fitted with a nonlinear Briére model which estimated optimal temperatures to be 24.5 and 26.2?°C with upper development thresholds of 29.3 and 31.4?°C for egg and nymph, respectively. In a linear model, lower development thresholds were 7.6 and 5.2?°C for egg and nymph, respectively. Survivorship was the highest at 21.0 and 22.2?°C for egg and nymph, respectively. Mean fecundity ranged from 14.4 eggs at 17.5?°C to 32.0 eggs at 23.5?°C. It was fitted to an extreme value function. Adult survival and cumulative oviposition rate of R. irregulariterdentatus were fitted to a sigmoid function and a two-parameter Weibull function, respectively. These models can be used to forecast phenology and population dynamics of R. irregulariterdentatus in the fields and optimize environmental conditions for rearing R. irregulariterdentatus.     

Lipocalin 2 (Lcn2) interferes with iron uptake by Brucella abortus and dampens immunoregulation during infection of RAW 264.7 macrophages

Lipocalin 2 (Lcn2) is an important innate immunity component against bacterial pathogens. In this study, we report that Lcn2 is induced by Brucella (B.) abortus infection and significantly contributes to the restriction of intracellular survival of Brucella in macrophages. We found that Lcn2 prevented iron uptake by B. abortus through two distinct mechanisms. First, Lcn2 is secreted to capture bacterial siderophore(s) and abrogate iron import by Brucella. Second, Lcn2 decreases the intracellular iron levels during Brucella infection, which probably deprives the invading Brucella of the iron source needed for growth. Suppression of Lcn2 signalling resulted in a marked induction of anti‐inflammatory cytokine, interleukin 10, which was shown to play a major role in Lcn2‐induced antibrucella immunity. Similarly, interleukin 6 was also found to be increased when Lcn2 signalling is abrogated; however, this induction was thought to be an alternative pathway that rescues the cell from infection when the effective Lnc2 pathway is repressed. Furthermore, Lcn2 deficiency also caused a marked decrease in brucellacidal effectors, such as reactive oxygen species and nitric oxide but not the phagolysosome fusion. Taken together, our results indicate that Lcn2 is required for the efficient restriction of intracellular B. abortus growth that is through limiting iron acquisition and shifting cells to pro‐inflammatory brucellacidal activity in murine macrophages.     

Mechanical features of various silkworm crystalline considering hydration effect via molecular dynamics simulations

Silk materials are receiving significant attention as base materials for various functional nanomaterials and nanodevices, due to its exceptionally high mechanical properties, biocompatibility, and degradable characteristics. Although crystalline silk regions are composed of various repetitive motifs with differing amino acid sequences, how the effect of humidity works differently on each of the motifs and their structural characteristics remains unclear. We report molecular dynamics (MD) simulations on various silkworm fibroins composed of major motifs (i.e. (GAGAGS)_n, (GAGAGA)_n, and (GAGAGY)_n) at varying degrees of hydration, and reveal how each major motifs of silk fibroins change at each degrees of hydration using MD simulations and their structural properties in mechanical perspective via steered molecular dynamics simulations. Our results explain what effects humidity can have on nanoscale materials and devices consisting of crystalline silk materials.     

Pin1-mediated Modification Prolongs the Nuclear Retention of β-Catenin in Wnt3a-induced Osteoblast Differentiation

The canonical Wnt signaling pathway, in which β-catenin nuclear localization is a crucial step, plays an important role in osteoblast differentiation. Pin1, a prolyl isomerase, is also known as a key enzyme in osteogenesis. However, the role of Pin1 in canonical Wnt signal-induced osteoblast differentiation is poorly understood. We found that Pin1 deficiency caused osteopenia and reduction of β-catenin in bone lining cells. Similarly, Pin1 knockdown or treatment with Pin1 inhibitors strongly decreased the nuclear β-catenin level, TOP flash activity, and expression of bone marker genes induced by canonical Wnt activation and vice versa in Pin1 overexpression. Pin1 interacts directly with and isomerizes β-catenin in the nucleus. The isomerized β-catenin could not bind to nuclear adenomatous polyposis coli, which drives β-catenin out of the nucleus for proteasomal degradation, which consequently increases the retention of β-catenin in the nucleus and might explain the decrease of β-catenin ubiquitination. These results indicate that Pin1 could be a critical target to modulate β-catenin-mediated osteogenesis.     

Enhanced cellular delivery and transfection efficiency of plasmid DNA using positively charged biocompatible colloidal gold nanoparticles

Efficient and safe nonviral gene delivery systems are a prerequisite for the clinical application of therapeutic genes. In this study, we report an enhancement of the transfection efficiency of plasmid DNA, via the use of positively charged colloidal gold nanoparticles (PGN). Plasmid DNA encoding for murine interleukin-2 (pVAXmIL-2) was complexed with PGN at a variety of ratios. The delivery of pVAXmIL-2 into C2C12 cells was dependent on the complexation ratios between PGN and the plasmid DNA, presented the highest delivery at a ratio of 2400:1. After complexation with DNA, PGN showed significantly higher cellular delivery and transfection efficiency than did the polyethylenimines (PEI) of different molecular weights, such as PEI25K (m.w. 25 kd) and PEI2K (m.w. 2 kd). PGN resulted in a cellular delivery of pVAXmIL-2 6.3-fold higher than was seen with PEI25K. The PGN/DNA complex resulted in 3.2- and 2.1-fold higher murine IL-2 protein expression than was seen in association with the PEI25K/DNA and PEI2K/DNA complexes, respectively. Following intramuscular administration, PGN/DNA complexes showed more than 4 orders of magnitude higher expression levels as compared to naked DNA. Moreover, the PGN/DNA complexes showed higher cell viability than other cationic nonviral vectors. Collectively, the results of this study suggest that the PGN/DNA complexes may harbor the potential for development into efficient and safe gene delivery vehicles.     

Acyl-CoA: cholesterol acyltransferase inhibitory activity of ginseng sapogenins, produced from the ginseng saponins.

Ginseng sapogenins were produced from ginseng saponins, isolated from Korean ginseng roots. Ginseng saponins very mildly inhibited acyl-CoA:cholesterol acyltransferase (ACAT) in vitro, however, the sapogenins showed strong inhibitory activity on microsomal ACAT. Therefore, the sapogenins will be one of key ingredients of ginseng affected a lowering of the serum total cholesterol level.     

Gaegurin 4, a peptide antibiotic of frog skin, forms voltage-dependent channels in planar lipid bilayers.

Gaegurin 4 (GGN4) is a cationic peptide of 37 amino acids (MW 3748) isolated from the skin of Rana rugosa. It has shown a broad spectrum antimicrobial activity in vitro against Gram-negative and -positive bacteria, fungi and protozoa. To understand its mechanism of antimicrobial action, we examined the effect of GGN4 on the membrane conductance and the electrical properties of GGN4-induced pores in planar lipid bilayers under voltage clamp. Natural and synthetic GGN4 (0.01-1 microg/mL) increased the membrane conductance in a concentration-dependent manner, but GGN4 (1-23), an N-terminal fragment of the peptide with little antimicrobial activity, failed to increase the conductance. At symmetrical 100 mM KCI, unitary conductances of about 120 pS were frequently observed. Their current-voltage relations were linear and open state probabilities were close to 1, but longer closing events were seen more frequently at negative voltages. In addition, GGN4-induced pores were selective for cation over anion, the permeability ratio of K+ to Cl- being 6: 1 in neutral and 7: 1 in acidic lipid bilayers. In conclusion, our results indicate that GGN4 forms voltage-dependent and cation-selective pores in planar lipid bilayers. The ionophoric property of GGN4 is likely to contribute to its antimicrobial activity.