Susceptibility of human H3N2 influenza virus to oseltamivir in South Korea, 2009–2011

During the 2009–2011 influenza seasons, 10.26% of the specimens isolated from patients in South Korea were subtyped as H3N2 viruses. Some oseltamivir-sensitive H3N2 samples exhibited different plaque morphologies, and were found to have novel mutations in the neuraminidase gene. In a subsequent analysis using NA mutant viruses, viral compensation against oseltamivir treatment was observed only in the N2 mutant virus. All things considered, these novel mutations may account for the exclusive characteristics of selected H3N2 viruses observed in plaque reduction assays.     

Methyl jasmonate and salicylic acid elicitation induces ginsenosides accumulation, enzymatic and non-enzymatic antioxidant in suspension culture Panax ginseng roots in bioreactors

The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O₂ ⁻), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 μM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O₂ ⁻ accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O₂ ⁻ stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures.     

Effect of carbon dioxide on antioxidant enzymes and ginsenoside production in root suspension cultures of Panax ginseng

The aim of this study was to investigate the effect of CO₂ at various concentrations (1, 2.5 and 5%) on antioxidant enzymes and ginsenoside accumulation in Panax ginseng roots in 5 l airlift bioreactors (working volume 4 l). One and 2.5% CO₂ was beneficial for root biomass accumulation, but 5% CO₂ decreased the biomass. Ginsenoside concentration decreased with increasing concentration of CO₂. No significant difference was observed in the malondialdehyde (MDA) content and lipoxygenase (LOX) activity between respective controls and CO₂ treated roots. Antioxidant enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), catalase (CAT), guaiacol peroxidase (G-POD) including reduced ascorbate and total glutathione were induced in CO₂ exposed roots which emphasized the protective role of antioxidants against CO₂ induced stress. Superoxide dismutase activity (SOD) which was induced after 15 days was significantly inhibited after 45 days. Glutathione-S-transferase (GST) and glutathione peroxidase (GPX) activities also increased when the roots were subjected to 1 and 2.5% CO₂ compared to the respective controls but not at 5%. A higher reduced ascorbate to oxidized (ASC/DHA) ratio in CO₂ treated root indicates the plant's ability to tolerate CO₂ stress. These observations suggest that an increase in antioxidant enzymes may affect a defense response to the cellular damage induced by CO₂. Probably, this increase could not stop the deleterious effects of CO₂ concentration on ginsenoside concentration, but reduced stress severity and thereby allowing root growth to occur.     

Gene-environment interactions in a mutant mouse kindred with native airway constrictor hyperresponsiveness

We mutagenized male BTBR mice with N-ethyl-N-nitrosourea and screened 1315 of their G3 offspring for airway hyperresponsiveness. A phenovariant G3 mouse with exaggerated methacholine bronchoconstrictor response was identified and his progeny bred in a nonspecific-pathogen-free (SPF) facility where sentinels tested positive for minute virus of mice and mouse parvovirus and where softwood bedding was used. The mutant phenotype was inherited through G11 as a single autosomal semidominant mutation with marked gender restriction, with males exhibiting almost full penetrance and very few females phenotypically abnormal. Between G11 and G12, facility infection eradication was undertaken and bedding was changed to hardwood. We could no longer detect airway hyperresponsiveness in more than 37 G12 offspring of 26 hyperresponsive G11 males. Also, we could not identify the mutant phenotype among offspring of hyperresponsive G8–G10 sires rederived into an SPF facility despite 21 attempts. These two observations suggest that both genetic and environmental factors were needed for phenotype expression. We suspect that rederivation into an SPF facility or altered exposure to pathogens or other unidentified substances modified environmental interactions with the mutant allele, and so resulted in disappearance of the hyperresponsive phenotype. Our experience suggests that future searches for genes that confer susceptibility for airway hyperresponsiveness might not be able to identify some genes that confer susceptibility if the searches are performed in SPF facilities. Experimenters are advised to arrange for multigeneration constancy of mouse care in order to clone mutant genes. Indeed, we were not able to map the mutation before losing the phenotype.     

Ginsenoside Re Rescues Methamphetamine-Induced Oxidative Damage,Mitochondrial Dysfunction,Microglial Activation,and Dopaminergic Degeneration by Inhibiting the Protein Kinase Cδ Gene

Ginsenoside Re, one of the main constituents of Panax ginseng, possesses novel antioxidant and anti-inflammatory properties. However, the pharmacological mechanism of ginsenoside Re in dopaminergic degeneration remains elusive. We suggested that protein kinase C (PKC) δ mediates methamphetamine (MA)-induced dopaminergic toxicity. Treatment with ginsenoside Re significantly attenuated methamphetamine-induced dopaminergic degeneration in vivo by inhibiting impaired enzymatic antioxidant systems, mitochondrial oxidative stress, mitochondrial translocation of protein kinase Cδ, mitochondrial dysfunction, pro-inflammatory microglial activation, and apoptosis. These protective effects were comparable to those observed with genetic inhibition of PKCδ in PKCδ knockout (?/?) mice and with PKCδ antisense oligonucleotides, and ginsenoside Re did not provide any additional protective effects in the presence of PKCδ inhibition. Our results suggest that PKCδ is a critical target for ginsenoside Re-mediated protective activity in response to dopaminergic degeneration induced by MA.     

PKCδ inhibition enhances tyrosine hydroxylase phosphorylation in mice after methamphetamine treatment

The present study was designed to evaluate the specific role of protein kinase C (PKC) δ in methamphetamine (MA)-induced dopaminergic toxicity. A multiple-dose administration regimen of MA significantly increases PKCδ expression, while rottlerin, a PKCδ inhibitor, significantly attenuates MA-induced hyperthermia and behavioral deficits. These behavioral effects were not significantly observed in PKCδ antisense oligonucleotide (ASO)-treated- or PKCδ knockout (−/−)-mice. There were no MA-induced significant decreases of dopamine (DA) content or tyrosine hydroxylase (TH) expression in the striatum in rottlerin-treated-, ASO-treated- or PKCδ (−/−)-mice. The administration of MA also results in a significant decrease of TH phosphorylation at ser 40, but not ser 31, while the inhibition of PKCδ consistently and significantly attenuates MA-induced reduction in the phosphorylation of TH at ser 40. Therefore, these results suggest that the MA-induced enhancement of PKCδ expression is a critical factor in the impairment of TH phosphorylation at ser 40 and that pharmacological or genetic inhibition of PKCδ may be protective against MA-induced dopaminergic neurotoxicity in vivo.