Toxoplasma gondii infection triggers ongoing inflammation mediated by increased intracellular Cl- concentration in airway epithelium.

Toxoplasma gondii is a widespread parasitic protozoan causing toxoplasmosis including pulmonary toxoplasmosis. As the first line of host defense, airway epithelial cells play critical roles in orchestrating pulmonary innate immunity. However, the mechanism underlying the airway inflammation induced by the T. gondii infection remains largely unclear. This study demonstrated that after infection with T. gondii, the major anion channel located in the apical membranes of airway epithelial cells, cystic fibrosis transmembrane conductance regulator (CFTR), was degraded by the parasite-secreted cysteine proteases. The intracellular Cl- concentration ([Cl-]i) was consequently elevated, leading to activation of nuclear factor-κB (NF-κB) signaling via serum/glucocorticoid regulated kinase 1. Furthermore, the heightened [Cl-]i and activated NF-κB signaling could be sustained in a positive feedback regulatory manner resulting from decreased intracellular cAMP level through NF-κB-mediated up-regulation of phosphodiesterase 4. Conversely, the sulfur-containing compound allicin conferred anti-inflammatory effects on pulmonary toxoplasmosis by decreasing [Cl-]i via activation of CFTR. These results suggest that the intracellular Cl- dynamically modulated by T. gondii mediates sustained airway inflammation, which provides a potential therapeutic target against pulmonary toxoplasmosis.

Allicin Facilitates Airway Surface Liquid Hydration by Activation of CFTR.

Airway epithelium plays critical roles in regulating airway surface liquid (ASL), the alteration of which causes mucus stasis symptoms. Allicin is a compound released from garlic and harbors the capacity of lung-protection. However, the potential regulatory effects of allicin on airway epithelium remain elusive. This study aimed to investigate the effects of allicin on ion transport across airway epithelium and evaluate its potential as an expectorant. Application of allicin induced Cl- secretion across airway epithelium in a concentration-dependent manner. Blockade of cystic fibrosis transmembrane conductance regulator (CFTR) or inhibition of adenylate cyclase-cAMP signaling pathway attenuated allicin-induced Cl- secretion in airway epithelial cells. The in vivo study showed that inhaled allicin significantly increased the ASL secretion in mice. These results suggest that allicin induces Cl- and fluid secretion across airway epithelium via activation of CFTR, which might provide therapeutic strategies for the treatment of chronic pulmonary diseases associated with ASL dehydration.

Pararobbsia silviterrae gen. nov., sp. nov., isolated from forest soil and reclassification of Burkholderia alpina as Pararobbsia alpina comb. nov.

A novel Gram-stain-negative, aerobic, non-spore-forming, non-motile and rod-shaped bacterial strain, DHC34T, was isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, China (112° 31' E 23° 10' N). It grew optimally on R2A medium at 28 °C, at pH 6.0-7.0 and in the presence of 0-1 % (w/v) NaCl. Strain DHC34T was closely related to Burkholderia alpina LMG 28138T (98.5 % 16S rRNA gene sequence similarity). 16S rRNA gene sequence analysis showed that strain DHC34T formed a clade with B. alpina LMG 28138T, which is next to but branched deeply with Robbsia andropogonis ICMP 2807T. The phylogenetic relationships among these three strains were also supported with the phylogram based on concatenated partial gyrB, recA and trpB gene sequences. The phylogenomic tree generated with the UBCG tool showed that strains DHC34T and R. andropogonis ICMP 2807T were in a different clade. The DNA-DNA relatedness values between strain DHC34T and B. alpina LMG 28138T and R. andropogonis ICMP 2807T were much lower than 70 %. Strain DHC34T contained ubiquinone 8 as the major respiratory quinone. Its major fatty acids were C16 : 0, C17 : 0 cyclo and C19 : 0 cyclo ω8c. The DNA G+C content of strain DHC34T was 64.2 mol%. The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, three unidentified aminophospholipids, four unidentified phospholipids, one unidentified aminolipid and a polar lipid. The phenotypic, phylogenetic, genotypic and chemotaxonomic data showed that strain DHC34T represents a novel species of a new genus in the family Burkholderiaceae, for which the name Pararobbsia silviterrae gen. nov., sp. nov. is proposed. The type strain of Pararobbsia silviterrae is DHC34T (=KCTC 42628T=LMG 28845T). On the basis of the current data, Burkholderia alpina is renamed as Pararobbsia alpina comb. nov.

Paraburkholderia pallida sp. nov. and Paraburkholderia silviterrae sp. nov., isolated from forest soil.

Two Gram-stain-negative, aerobic, motile, white-pigmented and rod-shaped bacterial strains, 7MH5T and 4 M-K11T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain 7MH5T grew at 4-37 °C (optimum, 28-33 °C), pH 3.5-9.0 (pH 4.0-5.5) and in the presence of 0-3 % (w/v) NaCl (0-1.5 w/v); while strain 4 M-K11T grew at 4-42 °C (20-33 °C), pH 3.5-8.5 (pH 4.5-6.0) and in the presence of 0-2.5 % (w/v) NaCl (0-1.5 w/v). Strains 7MH5T and 4 M-K11T have the highest 16S rRNA gene sequence similarities of 98.6 and 98.7 % to Paraburkholderia peleae PP52-1T, and 98.4 % between themselves. In the 16S rRNA gene sequence phylogram, strains 4 M-K11T and Paraburkholderia ferrariae NBRC 106233T formed a clade while 7MH5T were relatively distinct from other Paraburkholderia species. Based on the UBCG phylogenomic analysis, strains 7MH5T and 4 M-K11T formed a clade with Paraburkholderia oxyphila NBRC 105797T and Paraburkholderia sacchari LMG 19450T in the genus of Paraburkholderia. The DNA G+C contents of strains 7MH5T and 4 M-K11T were 64.2 and 64.3 %, respectively. Digital DNA-DNA hybridization and the average nucleotide identity values of strains 7MH5T, 4 M-K11T and closely related strains were in the ranges of 25.2-63.6 % and 81.0-95.5 %, respectively. The two strains had the same major respiratory quinone: ubiquinone-8. Strain 7MH5T had C16 : 0, C17 : 0cyclo, C19 : 0cyclo ω8c and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) as its major fatty acids, while strain 4 M-K11T had major fatty acids of C16 : 0, C17 : 0cyclo and summed feature 2 (iso-C16 : 1 I/C14 : 0-3OH). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of phenotypic and phylogenetic analyses based on both 16S rRNA gene and whole genome sequences, as well as chemotaxonomic data, strains 7MH5T and 4 M-K11T represent two novel species of the genus Paraburkholderia, for which the names Paraburkholderia pallida sp. nov. (type strain 7MH5T=GDMCC 1.1450T=KACC 19962T) and Paraburkholderia silviterrae sp. nov. (type strain 4 M-K11T=GDMCC 1.1284T=CGMCC 1.15450T=KACC 19961T=LMG 29217T) are proposed.

Isoprenylated Flavonoids from Roots of Artocarpus styracfolius.

Seven isoprenylated flavonoids were isolated from Artocarpus styracifolius, including one new triisoprenylated flavone, styracifolin D (1,) and six known ones, artocarpone B (2), kuwanon C (3), 6-C-prenyl luteolin (4), albanin A (5), 2,4,2',4'-tetrahydroxy-3'-(3-methyl-2-butenyl)-chalcone (6), and 3'-[γ-hydroxymethyl-(E)- γ-methylallyl]-2,4,2',4'-tetrahydroxychalcone 11'-0-coumarate (7). The structures of these compounds were determined by analysis of their spectroscopic and mass spectrometric data. Of them, 3 and 5 exhibited inhibitory effects on cathepsin K with IC(50) values of 114.6 and 7.4 µM, respectively.

[Inhibitory effects of cyclooxygenase-2 inhibitor celecoxib on the proliferation of hepatocellular carcinoma cells].

OBJECTIVE: To study the inhibitory effects of celecoxib, a cyclooxygenase-2 inhibitor, on the proliferation of hepatocellular carcinoma cells. METHODS: The in vitro inhibitory effects of celecoxib at different concentrations and for different treatment time lengths on human liver cancer cell line SMMC-7,721 were observed with MTT assay, and flow cytometry was performed to detect the cell cycle changes. The in vivo tumor inhibition effect of celecoxib was evaluated in Kunming mice bearing transplanted tumor derived from liver cancer cell line H22 transplantation. RESULT: Celecoxib significantly inhibited the in vitro growth of human liver cancer cell line SMMC-7721 in a time- and dose-dependent manner. A 36-hour celecoxib treatment (40 micromol/L) resulted in decreased SMMC-7721 cell proliferation and an increase of the cell percentage in G1 phase from 44.7% to 49.9% with decreased cell percentage in S and G(2)/M phases from 55.4% to 50.1%. In the mice bearing H22 transplanted tumor, celecoxib showed significant inhibitory effect on the growth and local metastasis of the transplanted tumor. CONCLUSION: Celecoxib can inhibit the proliferation of different liver cancer cell lines both in vitro and in vivo, and therefore may serve as an important candidate drug for prevention and treatment of hepatocellular carcinoma.