Structural requirement of phenylthiourea analogs for their inhibitory activity of melanogenesis and tyrosinase

Effect of a series of 1-phenylthioureas 1a-k and 1,3-disubstituted thioureas 2a-k were evaluated against melanin formation in melanoma B16 cell line and mushroom tyrosinase. Inhibitory activity of tyrosinase of 1-phenylthioureas 1a-k is parallel to their melanogenic inhibition. Thus, the melanogenic inhibition in melanoma B16 cells of 1-phenylthioureas could be the result of inhibition of tyrosinase. However, 1,3-diaryl or 1-phenyl-3-alkylthioureas, 2a-k, appears as melanogenic inhibitor without inhibition of tyrosinase. The molecular docking study of 1e and 2b to binding pocket of tyrosinase provided convincing explanation regarding the necessity of direct connection of planar phenyl to thiourea unit without N'-substitution of phenylthioureas 1 as tyrosinase inhibitor and 2 as non-tyrosinase inhibitor.     

Structural requirements of (E)-6-benzylidene-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one derivatives as novel melanogenesis inhibitors

Chalcone type compound 1a ((E)-6′-benzylidene-4a′-methyl-4′,4a′,7′,8′-tetrahydro-3′H-spiro[[1,3]dithiolane-2,2′-naphthalen]-5′(6′H)-one) was discovered as an potent inhibitor in melanogenesis. To define its structure-activity relationship, a series of analogs 1b-n, dithiolane truncated 2a-b and ring A removed 3a-e were prepared and evaluated. The electron donating substitution on the phenyl ring (ring C) rather than an electron withdrawing group and dithiolane motif of 1 are needed for the activity enhancement. The scaffold containing both rings A and B associated with α,β-unsaturated system connected to phenyl of 1 was essential for antimelanogenesis.     

Analysis of promoter methylation and polymorphic minisatellites of BORIS and lack of association with gastric cancer

BORIS is a member of the cancer-testis gene family that comprises genes normally expressed only in testis but abnormally activated in different malignancies. In this study, we examined the relation between BORIS expression and gastric cancer, which is the most common cancer in Korea. Abnormal BORIS expression in the patient's gastric cancer tissues was observed. We checked the methylation status of the gene in gastric cancer tissue, because the regulation by methylation in its CpG islands is well known for BORIS. However, there was no correlation between the methylation status and gene expression. Then, we focused on the minisatellites (variable number of tandem repeats) of BORIS as another possible regulator for this abnormal expression. Previously, we reported the characterization of BORIS-MS2 and determined the frequency of alleles in cancer patients. A case-control study was performed using DNA from 774 controls and 496 patients with gastric cancer. There was no significant difference observed in the overall distribution of minisatellite alleles. These results suggest that additional different regulators for the abnormal BORIS expression in gastric cancer may exist. Additionally, we performed a segregation analysis of BORIS-MS2 with genomic DNA obtained from two generations of five families and from three generations of two families. BORIS-MS2 alleles were transmitted through meiosis following Mendelian inheritance, which suggests that this polymorphic minisatellite could be a useful marker for paternity mapping and DNA fingerprinting.     

Characterization and expression of the pseudorabies virus (NYJ strain) glycoproteins in Bombyx mori cells and larvae

To characterize the NYJ strain of pseudorabies virus (PRV; Alphaherpesvirus of swine) isolated from the serum of an infected swine in Korea, the nucleotide sequence of three major glycoproteins (gB, gC, and gD) was analyzed. The expression of most potent immunogenic glycoprotein (gD) was also investigated using a Bombyx mori nucleopolyhedrovirus (BmNPV) expression system. The length of the glycoprotein genes corresponding to gB, gC, and gD of the NYJ strain were 2751 bp, 1443 bp, and 1203, respectively, and their identity ranged from 94.2% to 99.8% when compared with other strains. Phylogenetic analyses using these sequences showed that the NYJ strain forms a distinct branch with high bootstrap support. A novel transfer vector (pBmKSK4) was engineered with the polyhedrin promoter of BmNPV and a 6xHis tag to express glycoprotein gD in Bm5 cells and silkworm, B. mori, larvae. The immunogenicity of recombinant gD was demonstrated by its specific detection in both Bm5 cells and silkworm larvae by porcine anti-PRV antibody. The results of this study have implications both for the taxonomy of Korean PRV strains and vaccine development.     

miR451 and AMPK mutual antagonism in glioma cell migration and proliferation: a mathematical model

Glioblastoma multiforme (GBM) is the most common and the most aggressive type of brain cancer; the median survival time from the time of diagnosis is approximately one year. GBM is characterized by the hallmarks of rapid proliferation and aggressive invasion. miR-451 is known to play a key role in glioblastoma by modulating the balance of active proliferation and invasion in response to metabolic stress in the microenvironment. The present paper develops a mathematical model of GBM evolution which focuses on the relative balance of growth and invasion. In the present work we represent the miR-451/AMPK pathway by a simple model and show how the effects of glucose on cells need to be "refined" by taking into account the recent history of glucose variations. The simulations show how variations in glucose significantly affect the level of miR-451 and, in turn, cell migration. The model predicts that oscillations in the levels of glucose increase the growth of the primary tumor. The model also suggests that drugs which upregulate miR-451, or block other components of the CAB39/AMPK pathway, will slow down glioma cell migration. The model provides an explanation for the growth-invasion cycling patterns of glioma cells in response to high/low glucose uptake in microenvironment in vitro, and suggests new targets for drugs, associated with miR-451 upregulation.     

<Emphasis Type="Italic">Luteimonas aestuarii</Emphasis> sp. nov., isolated from tidal flat sediment

A novel bacterium B9^T was isolated from tidal flat sediment. Its morphology, physiology, biochemical features, and 16S rRNA gene sequence were characterized. Colonies of this strain are yellow and the cells are Gram-negative, rod-shaped, and do not require NaCl for growth. The 16S rRNA gene sequence similarity indicated that strain B9^T is associated with the genus Lysobacter (≤ 97.2%), Xanthomonas (≤ 96.8%), Pseudomonas (≤ 96.7%), and Luteimonas (≤ 96.0%). However, within the phylogenetic tree, this novel strain shares a branching point with the species Luteimonas composti CC-YY255^T (96.0%). The DNA-DNA hybridization experiments showed a DNA-DNA homology of 23.0% between strain B9^T and Luteimonas mephitis B1953/27.1^T. The G+C content of genomic DNA of the type strain is 64.7 mol% (SD, 1.1). The predominant fatty acids are iso-C_11:0, iso-C_15:0, iso-C_16:0, iso-C_17:0, iso-C_17:0 ω9c, and iso-C_11:0 3-OH. Combined analysis of the 16S rRNA gene sequences, fatty acid profile, and results from physiological and biochemical tests indicated that there is genotypic and phenotypic differentiation of the isolate from other Luteimonas species. For these reasons, strain B9^T was proposed as a novel species, named Luteimonas aestuarii. The type strain of the new species is B9^T (= KCTC 22048^T, DSM 19680^T).     

<Emphasis Type="Italic">Zunongwangia flava</Emphasis> sp. nov., belonging to the family <Emphasis Type="Italic">Flavobacteriaceae</Emphasis>, isolated from <Emphasis Type="Italic">Salicornia europaea</Emphasis>

A yellow pigmented bacterium designated strain MBLN094^T within the family Flavobacteriaceae was isolated from a halophyte Salicornia europaea on the coast of the Yellow Sea. This strain was a Gram-stain negative, aerobic, non-spore forming, rod-shaped bacterium. Phylogenetic analysis of the 16S rRNA gene sequence of strain MBLN094^T was found to be related to the genus Zunongwangia, exhibiting 16S rRNA gene sequence similarity values of 97.0, 96.8, 96.4, and 96.3% to Zunongwangia mangrovi P2E16^T, Z. profunda SM-A87^T, Z. atlantica 22II14-10F7^T, and Z. endophytica CPA58^T, respectively. Strain MBLN094^T grew at 20?37°C (optimum, 25?30°C), at pH 6.0?10.0 (optimum, 7.0?8.0), and with 0.5?15.0% (w/v) NaCl (optimum, 2.0?5.0%). Menaquinone MK-6 was the sole respiratory quinone. The polar lipids were phosphatidylethanolamine, two unidentified aminolipids, and four unidentified lipids. Major fatty acids were iso-C_17:0 3-OH, summed feature 3 (C_16:1ω6c and/or C16:1 ω7c), and iso-C_15:0. The genomic DNA G + C content was 37.4 mol%. Based on these polyphasic taxonomic data, strain MBLN094^T is considered to represent a novel species of the genus Zunongwangia, for which the name Zunongwangia flava sp. nov. is proposed. The type strain is MBLN094^T (= KCTC 62279^T = JCM 32262^T).     

Induction method of tyrosine kinase A-mediated cell death in rat pheochromocytoma

Nerve Growth Factor (NGF) is a neurotrophic factor that prevents apoptosis in neuronal progenitor cells. In rat pheochromocytoma (PC12) cells, tyrosine kinase A receptor (TrkA) mediates neurotrophic or protective effects, while p75 neurotrophin receptor (p75NTR) functions as a death receptor. We have determined whether TrkA mediates any cytotoxic effect. Following serum deprivation, TrkA expression increased 2.2-fold and apoptosis began with expression of Bax proapoptotic protein. Application of NGF halved cell viability but this was reversed by K252a, the TrkA inhibitor. These results confirmed the paradoxical cytotoxic effect of neurotrophic NGF via TrkA in PC12 cells following serum deprivation.