Influenza A H5N1 clade 2.3.4 virus with a different antiviral susceptibility profile replaced clade 1 virus in humans in northern Vietnam

Background

Prior to 2007, highly pathogenic avian influenza (HPAI) H5N1 viruses isolated from poultry and humans in Vietnam were consistently reported to be clade 1 viruses, susceptible to oseltamivir but resistant to amantadine. Here we describe the re-emergence of human HPAI H5N1 virus infections in Vietnam in 2007 and the characteristics of the isolated viruses.

Methods and Findings

Respiratory specimens from patients suspected to be infected with avian influenza in 2007 were screened by influenza and H5 subtype specific polymerase chain reaction. Isolated H5N1 strains were further characterized by genome sequencing and drug susceptibility testing. Eleven poultry outbreak isolates from 2007 were included in the sequence analysis. Eight patients, all of them from northern Vietnam, were diagnosed with H5N1 in 2007 and five of them died. Phylogenetic analysis of H5N1 viruses isolated from humans and poultry in 2007 showed that clade 2.3.4 H5N1 viruses replaced clade 1 viruses in northern Vietnam. Four human H5N1 strains had eight-fold reduced in-vitro susceptibility to oseltamivir as compared to clade 1 viruses. In two poultry isolates the I117V mutation was found in the neuraminidase gene, which is associated with reduced susceptibility to oseltamivir. No mutations in the M2 gene conferring amantadine resistance were found.

Conclusion

In 2007, H5N1 clade 2.3.4 viruses replaced clade 1 viruses in northern Vietnam and were susceptible to amantadine but showed reduced susceptibility to oseltamivir. Combination antiviral therapy with oseltamivir and amantadine for human cases in Vietnam is recommended.     

Retarded Charge–Carrier Recombination in Photoelectrochemical Cells from Plasmon‐Induced Resonance Energy Transfer

N‐type metal oxides such as hematite (α‐Fe₂O₃) and bismuth vanadate (BiVO₄) are promising candidate materials for efficient photoelectrochemical water splitting; however, their short minority carrier diffusion length and restricted carrier lifetime result in undesired rapid charge recombination. Herein, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern (hereafter, Au array) is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer‐printing process. Through plasmon‐induced resonance energy transfer, the Au array provides a strong electromagnetic field in the near‐surface area of the metal oxide film. The near‐field coupling interaction and amplification of the electromagnetic field suppress the charge recombination with long‐lived photogenerated holes and simultaneously enhance the light harvesting and charge transfer efficiencies. Consequently, an over 3.3‐fold higher photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) is achieved for the Au array/α‐Fe₂O₃. Furthermore, the high versatility of this transfer printing of Au arrays is demonstrated by introducing it on the molybdenum‐doped BiVO₄ film, resulting in 1.5‐fold higher photocurrent density at 1.23 V versus RHE. The tailored metal film design can provide a potential strategy for the versatile application in various light‐mediated energy conversion and optoelectronic devices.     

Two Helminthic Cases of Human Mummy Remains from Joseon-Period Graves in Korea

Our previous research on coprolite specimens from the mummies of Joseon Dynasty (1392–1910 CE) has revealed various species of parasite eggs. Herein, we added 2 new helminthic cases of human remains from Joseon-period graves in the Republic of Korea (Korea). The organic materials precipitated on the hip bones of 2 half-mummied cases (Goryeong and Gwangmyeong cases) were collected, rehydrated, and examined by a microscope. In the sample from Goryeong-gun (gun=County), ova of Trichuris trichiura, Clonorchis sinensis, and Metagonimus spp. were detected, and eggs of T. trichiura and A. lumbricoides were found from the sample of Gwangmyeong-si (si=City). By adding this outcome to the existing data pool, we confirm our previous estimates of Joseon-period parasite infection rates. The overall rates of A. lumbricoides, T. trichiura, and C. sinensis decreased dramatically from Joseon to the modern period. In Goryeong mummy specimen, we also found Metagonimus spp. eggs that has rarely been detected in archaeological samples so far.     

Intracellular protein phosphorylation in oat (Avena sativa L.) protoplasts by phytochrome action. 1. Measurement of action spectra for the protein phosphorylation

The effects of red light and wavelength dependency of the protein phosphorylation in oat protoplasts were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. Red light (660 nm) irradiation of the protoplasts increased the phosphorylation of 15 different proteins, and the phosphorylation of 2 proteins (27 KDa, 32 KDa) out of 15 were observed to be dependent on the wavelength of the irradiating light. The phosphorylation densities of these two proteins increased up to two or three hundred percent during a three-minute period of irradiation. The phosphorylation of these two proteins revealed a red/far-red photoreversibility of phytochrome. When a calcium ion chelator (2 mM EGTA) was added into the cell suspension, the phosphorylations of all the proteins were reduced about 200%. These findings suggest that phytochrome action and Ca2+ influx are certainly involved in the in vivo phosphorylation of proteins in oat protoplasts.     

Minimal requirements for the human immunodeficiency virus type 1 V3 domain to support the syncytium-inducing phenotype: analysis by single amino acid substitution.

The third variable domain (V3) of the human immunodeficiency virus type 1 external envelope contains determinants of cell tropism, cytopathicity, and infectivity and elicits antibodies able to block infectivity in vitro and in vivo. Our study encompassed point-mutational analysis of HXB-2 viruses containing patient-derived V3 regions and expressing a non-syncytium-inducing, low-replicating phenotype in T-cell line SupT1. The mutation within V3 of a serine at position 306 into an also naturally occurring arginine (S to R) required an additional, naturally occurring mutation at position 320 (aspartate to glutamine, D to Q) or 324 (aspartate to asparagine, D to N) for full expression of the syncytium-inducing, high-replicating (SI) phenotype. The naturally occurring mutation of an aspartate into an arginine at position 320 (D to R) was sufficient for production of the SI phenotype. This study proves that introduction of a positively charged amino acid at position 306 or 320, previously shown to be strongly associated with the SI phenotype in field isolates (R.A.M. Fouchier, M. Groenink, N.A. Kootstra, M. Tersmette, H.G. Huisman, F. Miedema, and H. Schuitemaker, J. Virol. 66:3183-3187, 1992), is minimally required for production of SI viruses. In addition, naturally occurring mutations at residue 324 also modulate the virus phenotype.     

Production of panose from maltose by intact cells of Aureobasidium pullulans

Panose, a major component of isomalto-oligosaccharides, was selectively produced from maltose using transglucosylation reaction catalyzed by intact cells of Aureobasidium pullulans. When 50 %(w/v) maltose was used as a substrate, the maximum concentration of panose accumulated in the final reaction mixture was about 50 %(w/w) after 120 hr reaction at 55 °C.     

Accumulation of galloyl derivatives in a green alga, Spirogyra varians, in response to cold stress

The green alga Spirogyra varians accumulated antioxidative compounds in response to cold stress. When the algae were transferred from 20°C to 4°C, the amount of phenolic contents and flavonoids in the cell increased 17 times and 30 times, respectively, in 2 months. At this time, the radical scavenging activity of the methanolic extract of S. varians was 238 times higher than that of initial culture. To identify the responsible antioxidants, the methanolic extract was obtained from the algae grown at 4°C. HPLC analysis of the extract showed six compounds newly produced or increased over time. Four of the compounds were successfully purified, and the structures were identified using ¹H NMR spectroscopy. The compounds were galloyl derivatives—methyl gallate, 1-O-Galloyl-β-d-glucose, 1,2,3,6-tetra-O-Galloyl-β-d-glucose and 1,2,3,4,6-penta-O-Galloyl-β-d-glucose which are intermediates of the shikimate pathway.