RESUMO
The first-order liquid-liquid phase transition in supercooled Si is revisited by long-time first-principle molecular dynamics simulations. As the focus of the present paper, its nature is revealed by analyzing the inherent structures of low-density liquid (LDL) and high-density liquid (HDL). Our results show that it is a transition between a sp(3)-hybridization LDL and a white-tin-like HDL. This uncovers the origin of the semimetal-metal transition accompanying it and also proves that HDL is the metastable extension of high temperature equilibrium liquid into the supercooled regime. The pressure-temperature diagram of supercooled Si thus can be regarded in some respects as shifted reflection of its crystalline phase diagram.
RESUMO
Interleukin 18 (IL-18), as a member of IL-1 superfamily, is an important pleiotropic cytokine that modulates Th1 immune responses. In this report, we cloned and identified a homolog of IL-18 in giant panda (Ailuropoda melanoleuca) (designated as AmIL-18) from peripheral blood mononuclear cells stimulated with lipopolysaccharide. The open readin g frame of AmIL-18 cDNA is 579 bp encoding a deduced protein of 192 amino acids. AmIL-18 gDNA fragments contained 5 exons and 4 introns. The amino acid sequence of AmIL-18 shared 23.9 to 87.0% identity with other species. To evaluate the effects of AmIL-18 on the immune response, we expressed the recombinant AmIL-18 in Escherichia coli BL21 (DE3). The fusion protein PET-AmIL-18 was purified by nickel affinity column chromatography and verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot analysis. The biological function of purified PET-AmIL-18 was determined on mouse splenocytes by quantitative real-time polymerase chain reaction. INF-γ and other cytokines were increased when stimulated by PET-AmIL-18, particularly when combined with recombinant human interleukin 12, while a Th2-type cytokine, interleukin-4, was strikingly suppressed. These results will provide information for the potential use of recombinant proteins to manipulate the immune response in giant pandas and facilitate the study to protect this treasured species.
Assuntos
Interleucina-18/genética , Leucócitos Mononucleares/imunologia , Fases de Leitura Aberta , Ursidae/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar/genética , DNA Complementar/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Éxons , Feminino , Expressão Gênica , Humanos , Interferon gama/biossíntese , Interferon gama/metabolismo , Interleucina-12/farmacologia , Interleucina-18/imunologia , Interleucina-4/biossíntese , Interleucina-4/metabolismo , Íntrons , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Linfócitos/imunologia , Camundongos , Dados de Sequência Molecular , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Homologia de Sequência de Aminoácidos , Baço/citologia , Baço/efeitos dos fármacos , Baço/imunologia , Ursidae/imunologiaRESUMO
Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4-10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1-3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1-10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5-8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5-10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.
Assuntos
Ascomicetos/química , Policetídeos/química , Policetídeos/farmacologia , Alternaria/efeitos dos fármacos , Ascomicetos/metabolismo , Dicroísmo Circular , Avaliação Pré-Clínica de Medicamentos/métodos , Endófitos/química , Células HeLa , Células Hep G2 , Humanos , Células MCF-7 , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Policetídeos/metabolismo , Metabolismo SecundárioRESUMO
Forty-six cases of mesotheliomas of rats induced by asbestos, 2 cases of human mesotheliomas and 10 cases of adenocarcinomas were studied by light microscopy, electron microscopy, histochemical and immunohistochemical staining. The results indicated that mesothelioma probably originates from the multipotential subserosal cell which has the features of myofibroblast. In addition to the epithelial, fibrous and mixed types of mesothelioma classified by WHO, poorly differentiated type of mesothelioma can also be found in rats. Electron microscopy, histochemical and immunohistochemical staining are very helpful in differentiating mesotheliomas from adenocarcinomas.