Two new antibacterial sesquiterpenoids from Centipeda minima

Two new guaiane-type sesquiterpene lactones, compounds 1 and 2, along with three known guaianolide- or pseudoguaianolides, were isolated from Centipeda minima (whole plant). Their structures were identified by spectroscopic and mass-spectrometric analyses. The configuration at C5 of the guaiane framework of 1 was rationalized by quantum-mechanical calculations (Table 2). All compounds were found to be active against eight different microbial pathogens (Table 3), with MIC values in the range of 6.25-100 microg/ml.     

Staphylococcal enterotoxin C1-induced pyrogenic cytokine production in human peripheral blood mononuclear cells is mediated by NADPH oxidase and nuclear factor-kappa B

The staphylococcal enterotoxins produced by Staphylococcus aureus are associated with pyrogenic response in humans and primates. This study investigates the role of NADPH oxidase and nuclear factor-kappa B (NF-kappaB) on enterotoxin staphylococcal enterotoxin C1 (SEC1)-induced pyrogenic cytokine production in human peripheral blood mononuclear cells (PBMC). The results indicate that the febrile response to the supernatant fluids of SEC1-stimulated PBMC in rabbits was in parallel with the levels of interleukin-1beta and interleukin-6 in the supernatants. The release of interleukin-1beta and interleukin-6, nuclear translocation of NF-kappaB and its DNA binding activity in the SEC1-stimulated PBMC were time-dependent and were completely eliminated by pyrrolidine dithiocarbamate or SN-50 (NF-kappaB inhibitors). The release of reactive oxygen species in the supernatants and translocation of the NADPH oxidase p47(phox) subunit to the plasma membrane of SEC1-stimulated PBMC were time-dependent. Administration of apocynin (NADPH oxidase inhibitor) attenuated the febrile response to the supernatants in rabbits and decreased the translocation of NADPH oxidase p47(phox) subunit and NF-kappaB activity in the SEC1-stimulated PBMC, and suppressed reactive oxygen species and pyrogenic cytokine production in the supernatants. Taken together, SEC1 may act through an NADPH oxidase mechanism to release reactive oxygen species, which activate NF-kappaB in PBMC to stimulate the synthesis of pyrogenic cytokines that trigger a fever response in rabbits.     

动物学综合实验在教学中培养探究性的实践

以动物学综合实验--家鸡脑标本的制作与观察为例,从药品的配制、实验材料的准备、实验整个操作程序的设计,到最后的实验结果,让学生独立完成.起到了指导学生探究和掌握科学方法的作用,让学生在体验科学探究的过程中,获得初步的科学探究能力,培养其探索和创新意识,从而提高生物科学素养.     

Inter-comparison of models to estimate radionuclide activity concentrations in non-human biota

A number of models have recently been, or are currently being, developed to enable the assessment of radiation doses from ionising radiation to non-human species. A key component of these models is the ability to predict whole-organism activity concentrations in a wide range of wildlife. In this paper, we compare the whole-organism activity concentrations predicted by eight models participating within the IAEA Environmental Modelling for Radiation Safety programme for a range of radionuclides to terrestrial and freshwater organisms. In many instances, there was considerable variation, ranging over orders of magnitude, between the predictions of the different models. Reasons for this variability (including methodology, data source and data availability) are identified and discussed. The active participation of groups responsible for the development of key models within this exercise is a useful step forward in providing the transparency in methodology and data provenance required for models which are either currently being used for regulatory purposes or which may be used in the future. The work reported in this paper, and supported by other findings, demonstrates that the largest contribution to variability between model predictions is the parameterisation of their transfer components. There is a clear need to focus efforts and provide authoritative compilations of those data which are available.     

Characterization of mitochondrial genome of Formosan sambar (Rusa unicolor swinhoei)

The complete mitochondrial genome sequence of the Formosan sambar (Rusa unicolor swinhoei) was obtained by DNA sequencing based on PCR fragments amplified by 26 primer pairs designed by ourselves. The results indicated that the mtDNA is 16,505 bp in size. This is the first report on mitochondrial DNA (mtDNA) sequence analysis of the Formosan sambar and the sequence was deposited in the GenBank database under the accession number DQ989636. The complete mitochondrial sequence included the following gene sequences: 12S and 16S rRNAs, 22 tRNAs and 13 protein-coding genes. The base composition of the sequence was as follows: A, 33.51%; T, 28.97%; C, 24.07%; and G, 13.46%. The mitochondrial D-loop region was also analyzed for comparative purposes in the Formosan sambar and 13 other species within the Cervidae family using neighbour-joining method. The phylogenetic tree demonstrated that there are two separate groups, a European type and an Asian type, within the Cervidae family. The D-loop sequences of mtDNA of 24 Formosan sambar animals were compared, and the results showed that the Formosan sambar can be divided into two clades.     

Enhancement of Astragalus polysaccharide on the immune responses in pigs inoculated with foot-and-mouth disease virus vaccine

The effects of Astragalus polysaccharides (APS) on the immune response in pigs immunized with foot-and-mouth disease virus (FMDV) vaccine were investigated. Fifteen pigs were randomly divided into five groups. Four groups were vaccinated with a FMDV inactivated vaccine. Pigs in three experimental groups were administered varying doses of APS (APS1, 5 mg/kg; APS2, 10 mg/kg; APS3, 20 mg/kg). The influence of APS on the number of CD3⁺CD4⁻CD8⁺ cytotoxic T cells, CD3⁺CD4⁺CD8⁺ T helper memory cells, and CD3⁻CD4⁻CD8⁺ natural killer cells among peripheral blood lymphocytes (PBL) in the three APS groups were significant compared to the vaccine group. In vitro stimulation of PBL by Con A and LPS in APS groups induced a stronger proliferative response at 2 and 6 weeks post-inoculation (PI). APS markedly increased the titer of FMDV-specific antibody in a dose-dependent manner, and up-regulated mRNA expression of IFN-γ and IL-6. APS could potentially be used as an immunomodulator for a FMDV vaccine and provide better protection against FMDV.     

Conserved Fiber-Penton Base Interaction Revealed by Nearly Atomic Resolution Cryo-Electron Microscopy of the Structure of Adenovirus Provides Insight into Receptor Interaction

Adenovirus (Ad) cell attachment is initiated by the attachment of the fiber protein to a primary receptor (usually CAR or CD46). This event is followed by the engagement of the penton base protein with a secondary receptor (integrin) via its loop region, which contains an Arg-Gly-Asp (RGD) motif, to trigger virus internalization. To understand the well-orchestrated adenovirus cell attachment process that involves the fiber and the penton base, we reconstructed the structure of an Ad5F35 capsid, comprising an adenovirus type 5 (Ad5) capsid pseudotyped with an Ad35 fiber, at a resolution of approximately 4.2 Å. The fiber-penton base interaction in the cryo-electron microscopic (cryo-EM) structure of Ad5F35 is similar to that in the cryo-EM structure of Ad5, indicating that the fiber-penton base interaction of adenovirus is conserved. Our structure also confirms that the C-terminal segment of the fiber tail domain constitutes the bottom trunk of the fiber shaft. Based on the conserved fiber-penton base interaction, we have proposed a model for the interaction of Ad5F35 with its primary and secondary receptors. This model could provide insight for designing adenovirus gene delivery vectors.     

Pyrroloquinoline quinone inhibits oxygen/glucose deprivation-induced apoptosis by activating the PI3K/AKT pathway in cardiomyocytes

The purposes of this study were to examine the protective effect of pyrroloquinoline quinone (PQQ) on oxygen/glucose deprivation (OGD)-induced injury to H9C2 rat cardiomyocytes and to investigate the mechanism. Using H9C2 cells cultured in vitro, we examined changes in cell viability with an MTT assay at 12, 24, and 48 h after injury induced by OGD. Various concentrations of PQQ (1, 10, and 100 μM) were added, and the effect of PQQ on cell viability after OGD was assessed using the MTT assay. Thus, the optimal concentration of PQQ for the protection of cardiomyocytes against oxygen and glucose deprivation injury was determined. We also used flow cytometry analysis to examine the effect of PQQ on H9C2 cells with OGD-induced injury. The molecular probe 2′,7′-dichlorofluorescin diacetate was used to label the H9C2 cells, and flow cytometry was used to detect the effect of PQQ on reactive oxygen species (ROS) content. After labeling the H9C2 cells using a mitochondrial green fluorescent probe (Mito-Tracker Green), we measured the change in the mitochondrial content of PQQ-treated H9C2 cells. Western blotting was used to examine the effect of PQQ on the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in the H9C2 cells. The results of the MTT assay showed that 48 h of OGD significantly injured the H9C2 cells (p < 0.01) and that treatment with 100 μM PQQ effectively decreased the level of OGD-induced injury (p < 0.01). The results of the flow cytometry analysis showed that PQQ significantly reduced apoptosis in H9C2 cells subjected to OGD (p < 0.05). In addition, OGD significantly increased the ROS level in H9C2 cells (p < 0.01), and PQQ significantly inhibited this increase (p < 0.05). The results of the Mito-Tracker Green staining suggested that PQQ effectively inhibited the decrease in mitochondrial content caused by OGD (p < 0.05). Western blot analysis showed that PQQ partially reversed the decrease in Akt phosphorylation that was caused by OGD (p < 0.05). PQQ treatment dose-dependently protects H9C2 cells from OGD-induced injury by reducing apoptosis, decreasing intracellular ROS levels, and rescuing the OGD-induced decrease in mitochondrial content. The protective effect of PQQ may be related to its effects on the PI3K/Akt pathway.     

Subgenomic promoter recognition by the norovirus RNA-dependent RNA polymerases

The replication enzyme of RNA viruses must preferentially recognize their RNAs in an environment that contains an abundance of cellular RNAs. The factors responsible for specific RNA recognition are not well understood, in part because viral RNA synthesis takes place within enzyme complexes associated with modified cellular membrane compartments. Recombinant RNA-dependent RNA polymerases (RdRps) from the human norovirus and the murine norovirus (MNV) were found to preferentially recognize RNA segments that contain the promoter and a short template sequence for subgenomic RNA synthesis. Both the promoter and template sequence contribute to stable RdRp binding, accurate initiation of the subgenomic RNAs and efficient RNA synthesis. Using a method that combines RNA crosslinking and mass spectrometry, residues near the template channel of the MNV RdRp were found to contact the hairpin RNA motif. Mutations in the hairpin contact site in the MNV RdRp reduced MNV replication and virus production in cells. This work demonstrates that the specific recognition of the norovirus subgenomic promoter is through binding by the viral RdRp.