Investigation of the Synergistic Toxicity of Binary Mixtures of Pesticides and Pharmaceuticals on Aliivibrio fischeri in Major River Basins in South Korea.

This work introduces the potential synergistic toxicity of binary mixtures of pesticides and pharmaceuticals, which have been detected in substantial amounts in major river basins in South Korea. Different dose-response curve functions were employed in each experimental toxicity dataset for Aliivibrio fischeri. We tested the toxicity of 30 binary mixtures at two effect concentrations: high effect concentration [EC50] and low effect concentration (EC10) ranges. Thus, the toxicological interactions were evaluated at 60 effected concentration data points in total and based on model deviation ratios (MDRs) between predicted and observed toxicity values (e.g., three types of combined effects: synergistic (MDR > 2), additive (0.5 ≤ MDR ≤ 2), and antagonistic (MDR < 0.5)). From the 60 data points, MDRs could not be applied to 17 points, since their toxicities could not be measured. The result showed 48%-additive (n = 20), 40%-antagonistic (n = 17), and 12%-synergistic (n = 6) toxicity effects from 43 binaries (excluding the 17 combinations without MDRs). In this study, EC10 ratio mixtures at a low overall effect range showed a general tendency to have more synergistic effects than the EC50 ratio mixtures at a high effect range. We also found an inversion phenomenon, which detected three binaries of the combination of synergism at low concentrations and additive antagonism at high concentrations.

Detection of Acidic Pharmaceutical Compounds Using Virus-Based Molecularly Imprinted Polymers.

Molecularly imprinted polymers (MIPs) have proven to be particularly effective chemical probes for the molecular recognition of proteins, DNA, and viruses. Here, we started from a filamentous bacteriophage to synthesize a multi-functionalized MIP for detecting the acidic pharmaceutic clofibric acid (CA) as a chemical pollutant. Adsorption and quartz crystal microbalance with dissipation monitoring experiments showed that the phage-functionalized MIP had a good binding affinity for CA, compared with the non-imprinted polymer and MIP. In addition, the reusability of the phage-functionalized MIP was demonstrated for at least five repeated cycles, without significant loss in the binding activity. The results indicate that the exposed amino acids of the phage, together with the polymer matrix, create functional binding cavities that provide higher affinity to acidic pharmaceutical compounds.

Full genomic characterization of a group C rotavirus isolated from a child in South Korea.

During an epidemiological survey of human rotavirus infection in Seoul, Korea, from 2010 to 2011, one isolate of group C rotavirus (GCRV), named CAU10-312, was detected in a 5-year-old child admitted to the hospital with acute gastroenteritis, and its complete genomic sequence was determined. The 11 gene segments of the strain possessed G4-P[2]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotypes. The genotype of strain CAU10-312 appears to be closely related to strains from Bangladesh (DhakaC13 and BS347), India (v508), and England (Bristol), but distinct from Far East Asian strains, Chinese (Wu82 and YNR001) and Japanese (OH567 and BK0830). These findings may clarify the relationship of the genetics, evolutionary biology, and epidemiology of GCRVs and suggest that two very distinct genotype strains are in circulation in the world.

Whole genomic analysis reveals the co-evolutionary phylodynamics of Korean G9P[8] human rotavirus strains.

Three human rotavirus G9P[8] strains, RVA/Human-tc/KOR/CAU05-202/2005/G9P[8], RVA/Human-tc/KOR/CAU09-371/2009/G9P[8], and RVA/Human-tc/KOR/CAU09-376/2009/G9P[8], were isolated from female pediatric patients with diarrhea from 2005 to 2009 using a cell culture system, and their complete genomic sequences were analyzed. The 11 gene segments of the three Korean strains possessed the G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 genotype, which is closely related to the Wa-like genotype 1 constellation. Interestingly, the NSP2 and the NSP3 genes of strain RVA/Human-tc/KOR/CAU09-376/2009/G9P[8] were related to the G9 porcine or human-porcine reassortant strains, providing evidence for porcine-to-human interspecies transmission.

Expression of recombinant rotavirus proteins harboring antigenic epitopes of the hepatitis a virus polyprotein in insect cells.

Rotavirus and hepatitis A virus (HAV) spread by the fecal-oral route and infections are important in public health, especially in developing countries. Here, two antigenic epitopes of the HAV polyprotein, domain 2 (D2) and domain 3 (D3), were recombined with rotavirus VP7, generating D2/VP7 and D3/VP7, cloned in a baculovirus expression system, and expressed in Spodoptera frugiperda 9 (Sf9) insect cells. All were highly expressed, with peak expression 2 days post-infection. Western blotting and ELISA revealed that two chimeric proteins were antigenic, but only D2/VP7 was immunogenic and elicited neutralizing antibody responses against rotavirus and HAV by neutralization assay, implicating D2/VP7 as a multivalent subunit-vaccine Candidate for preventing both rotavirus and HAV infections.

Molecular characterization of rotavirus diarrhea among children in South Korea: detection of an unusual G11 strain.

Among 312 rotavirus-positive samples collected from eight hospitals across South Korea during 2008 and 2009, the most prevalent circulating G genotype was G1 (35.9%), followed by G3 (24.7%), G2 (17.0%), G4 (7.7%), and G9 (2.6%). Notably, one unusual G11 lineage III strain-the first hypoendemic infection case in the world-was found. Of the P genotypes, P[8] (43.9%) was the most common, followed by P[6] (29.5%), P[4] (9.3%) and P[9] (0.6%). Determining G- and P-type combinations showed that G1P[8] was the most prevalent (20.5%), followed by G2P[6] (12.8%) and G3P[8] (12.8%). These findings provide new information concerning the current prevalence and spread of the rare G11 rotavirus.

Dextromethorphan attenuates trimethyltin-induced neurotoxicity via sigma1 receptor activation in rats.

We showed that dextromethorphan (DM) provides neuroprotective/anticonvulsant effects and that DM and its major metabolite, dextrorphan, have a high-affinity for sigma(1) receptors, but a low affinity for sigma(2) receptors. In addition, we found that DM has a higher affinity than DX for sigma(1) sites, whereas DX has a higher affinity than DM for PCP sites. We extend our earlier findings by showing that DM attenuated trimethyltin (TMT)-induced neurotoxicity (convulsions, hippocampal degeneration and spatial memory impairment) in rats. This attenuation was reversed by the sigma(1) receptor antagonist BD 1047, but not by the sigma(2) receptor antagonist ifenprodil. DM attenuates TMT-induced reduction in the sigma(1) receptor-like immunoreactivity of the rat hippocampus, this attenuation was blocked by the treatment with BD 1047, but not by ifenprodil. These results suggest that DM prevents TMT-induced neurotoxicity, at least in part, via sigma(1) receptor stimulation.