The First Report on the Complete Sequence Characterization of Bluetongue Virus Serotype 3 in the Republic of Korea

The bluetongue virus (BTV) is a significant animal pathogen with economic implications in the ruminant industry. Despite global reports on BTV detection and epidemiologic investigations, limited studies have focused on the virus in the ROK. In this study, BTV epidemiological research was conducted on blood samples from cattle and goat farms across nine regions during 2013-2014. The results showed that 3.33% of bovine blood samples (194/5824) and 0.19% of goat blood samples (2/1075) tested positive for BTV antibodies using ELISA. In Jeju-do, BTV RNA amplification occurred in 51 of 422 samples (12.1%) using real-time reverse transcription (RT-qPCR). The isolation of one sample revealed it as serotype 3, as indicated by the sequence of segments 2 (Seg-2) and 6 (Seg-6), associated with the eastern BTV topotype. However, based on Seg-1, -3, -4, -5, -7, -8, -9, and -10 analyses, the BTV-3/JJBB35 strain is more closely related to distinct BTV strains. These findings imply BTV circulation and that the Korean-isolated BTV might originate from Asian BTV strains due to multiple reassortment events. This study provides foundational data for ongoing BTV monitoring and disease-control policies in the ROK.

Pathogenicity and Pathological Characteristics of African Swine Fever Virus Strains from Pig Farms in South Korea from 2022 to January 2023

Since the first African swine fever (ASF) outbreak occurred at a pig farm in South Korea in September 2019, as of 31 January 2023, 31 ASF cases have occurred at pig farms, while 2799 ASF virus (ASFV)-infected wild boars have been identified. The circulation of ASFV in wild boar populations poses a high risk of spillover to pig farms in the country. However, information on the changes in the pathogenicity of Korean ASFV strains from wild boars is not available. Investigating the pathogenicity of ASFV strains from pig farms is the only way to predict their alterations. In a previous study, no changes in the pathogenicity of ASFV strains circulating during 2019-2021 were identified through animal experiments. In this study, we chose two ASFV strains with potentially reduced pathogenicity among ten viruses obtained from pig premises from 2022 to January 2023 and estimated their pathogenicities and pathological characteristics. All the inoculated pigs died 8-10 days post-inoculation after showing pyrexia, depression, anorexia, and recumbency together with the common pathological lesions of enlarged hemorrhagic lymph nodes and splenomegaly with infarction. These results support that the pathogenicity among ASFV isolates in South Korea still remained unchanged during the study period.

DPSC-Derived Extracellular Vesicles Promote Rat Jawbone Regeneration

Repair and functional reconstruction of large jawbone defects remain one of the challenges in the field of head and neck surgery. The recent progress in tissue engineering technologies and stem cell biology has significantly promoted the development of regenerative reconstruction of jawbone defects. The multiple trophic activities of extracellular vesicles (EVs) produced by mesenchymal stem cells (MSCs) may play a critical role in their therapeutic effects. Accumulating evidence has shown the promise of dental pulp stem cells (DPSCs) in bone regeneration, but less is known about the regenerative effects of DPSC-EVs on jawbone defects. The purpose of this study is to explore the osteogenic effects of DPSC-EVs on jawbone marrow-derived MSCs (JB-MSCs) in vitro and their osteoinductive effects in a mandibular bone defect model in rats. Our results showed that JB-MSCs could efficiently uptake DPSC-EVs, which in turn significantly promoted the expression of osteogenic genes, such as runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and osteocalcin (OCN), as well as the osteogenic differentiation capability of JB-MSCs. Meanwhile, we found that the pro-osteogenic effect in vitro induced by DPSC-EVs was comparable to that induced by BMP-2 (bone morphogenetic protein 2), currently the only Food and Drug Administration-approved osteoinductive growth factor. In vivo, animals that were locally treated with DPSC-EVs laden with a commercially available collagen membrane exhibited a relatively fast wound closure and increased new bone density at the mandible defects. Our results provide evidence for the osteogenic and osteoinductive effects of DPSC-EVs on jawbone regeneration. Due to the accessibility, rapid proliferation, and osteogenic propensity of DPSCs, DPSC-EVs may represent a safe cell-free therapeutic approach for craniofacial bone regeneration.

Selection of an Optimal Recombinant Egyptian H9N2 Avian Influenza Vaccine Strain for Poultry with High Antigenicity and Safety

For the development of an optimized Egyptian H9N2 vaccine candidate virus for poultry, various recombinant Egyptian H9N2 viruses generated by a PR8-based reverse genetics system were compared in terms of their productivity and biosafety since Egyptian H9N2 avian influenza viruses already possess mammalian pathogenicity-related mutations in the hemagglutinin (HA), neuraminidase (NA), and PB2 genes. The Egyptian HA and NA genes were more compatible with PR8 than with H9N2 AIV (01310) internal genes, and the 01310-derived recombinant H9N2 strains acquired the L226Q reverse mutation in HA after passages in eggs. Additionally, the introduction of a strong promoter at the 3′-ends of PB2 and PB1 genes induced an additional mutation of P221S. When recombinant Egyptian H9N2 viruses with intact or reverse mutated HA (L226Q and P221S) and NA (prototypic 2SBS) were compared, the virus with HA and NA mutations had high productivity in ECES but was lower in antigenicity when used as an inactivated vaccine due to its high binding affinity into non-specific inhibitors in eggs. Finally, we substituted the PB2 gene of PR8 with 01310 to remove the replication ability in mammalian hosts and successfully generated the best recombinant vaccine candidate in terms of immunogenicity, antigenicity, and biosafety.

Rank orders of mammalian pathogenicity-related PB2 mutations of avian influenza A viruses

The PB2 gene is one of the key determinants for the mammalian adaptation of avian influenza A viruses (IAVs). Although mammalian pathogenicity-related mutations (MPMs) in PB2 genes were identified in different genetic backgrounds of avian IAVs, the relative effects of single or multiple mutations on viral fitness could not be directly compared. Furthermore, their mutational steps during mammalian adaptation had been unclear. In this study, we collectively compared the effects of individual and combined MPMs on viral fitness and determined their rank orders using a prototypic PB2 gene. Early acquired mutations may determine the function and potency of subsequent mutations and be important for recruiting multiple, competent combinations of MPMs. Higher mammalian pathogenicity was acquired with the greater accumulation of MPMs. Thus, the rank orders and the prototypic PB2 gene may be useful for predicting the present and future risks of PB2 genes of avian and mammalian IAVs.

Outbreak of African swine fever in South Korea, 2019

African swine fever, a fatal haemorrhagic disease of swine, was confirmed in domestic pigs for the first time in South Korea in September 2019. The causative virus belonged to the p72 genotype II and had an additional tandem repeat sequence in the intergenic region (IGR) between the I73R and I329L.

Bioengineering a highly productive vaccine strain in embryonated chicken eggs and mammals from a non-pathogenic clade 2·3·4·4 H5N8 strain

The clade 2·3·4·4 H5Nx is a highly pathogenic avian influenza (HPAI) virus, which first appeared in China and has spread worldwide since then, including Korea. It is divided into subclades a - d, but the PR8-derived recombinant clade 2·3·4·4 a viruses replicate inefficiently in embryonated chicken eggs (ECEs). High virus titer in ECEs and no mammalian pathogenicity are the most important prerequisites of efficacious and safer vaccine strains against HPAI. In this study, we have synthesized hemagglutinin (HA) and neuraminidase (NA) genes based on the consensus amino acid sequences of the clade 2·3·4·4a and b H5N8 HPAIVs, using the GISAID database. We generated PR8-derived H5N8 recombinant viruses with single point mutations in HA and NA, which are related to efficient replication in ECEs. The H103Y mutation in HA increased mammalian pathogenicity as well as virus titer in ECEs, by 10-fold. We also successfully eradicated mammalian pathogenicity in H103Y-bearing H5N8 recombinant virus by exchanging PB2 genes of PR8 and 01310 (Korean H9N2 vaccine strain). The final optimized H5N8 vaccine strain completely protected against a heterologous clade 2·3·4·4c H5N6 HPAIV in chickens, and induced hemagglutination inhibition (HI) antibody in ducks. However, the antibody titer of ducks showed age-dependent results. Thus, H103Y and 01310PB2 gene have been successfully applied to generate a highly productive, safe, and efficacious clade 2·3·4·4 H5N8 vaccine strain in ECEs.

Serum ammonia as an early predictor of in-hospital mortality in patients with glufosinate poisoning

Background:

The mortality rate associated with human glufosinate poisoning is high. We evaluated the usefulness of serum ammonia and sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation II (APACHE II) scores for early prediction of in-hospital mortality in glufosinate ammonium poisoning.

Methods:

A prospectively collected pesticide poisoning registry at a single academic medical center was retrospectively analyzed. Data were collected from consecutive patients diagnosed with glufosinate ammonium poisoning between May 2007 and February 2018. The initial serum ammonia level was defined as the highest serum ammonia level measured within 12 h after emergency department (ED) arrival. The SOFA and APACHE II scores were calculated using data obtained within the first 12 h after ED arrival. The patients were divided into survivor and nonsurvivor groups by in-hospital death status.

Results:

In total, 110 patients were included. Ten patients (9.1%) died in the hospital despite treatment. Median initial serum ammonia level was significantly higher in the nonsurvivor group than in the survivor group (219 (range: 158–792) versus 100.5 (range: 25–317) µg/dL, p < 0.001). Median SOFA and APACHE II scores in the survivor and nonsurvivor groups were 2 (range: 0–10) versus 5 (range: 1–8) ( p = 0.044) and 7 (range: 0–28) versus 16 (range: 8–22) ( p = 0.001), respectively. In the multiple logistic regression analysis, the initial serum ammonia level was the only independent predictor (cutoff value: 151 µg/dL).

Conclusion:

An initial serum ammonia level >151 µg/dL was an independent early predictor of in-hospital mortality in glufosinate ammonium poisoning.

Generation of highly productive and mammalian nonpathogenic recombinant H9N2 avian influenza viruses by optimization of 3'end promoter and NS genome

We developed A/PR/8/34 (PR8) virus-based reverse genetics system in which six internal genes of PR8 and attenuated hemagglutinin and intact neuraminidase genes of field avian influenza viruses (AIVs) have been used for the generation of highly productive recombinant vaccine strains. The 6 + 2 recombinant vaccine strains can induce protective humoral immunity against intended field AIVs; however, the epitopes of B and T cells encoded by internal genes may be important for heterosubtypic protection. Therefore, it is advantageous to use homologous internal genes of field AIVs for recombinant vaccine strains. However, the rescue of recombinant viruses having whole internal genes of field AIVs by the PR8-based reverse genetics system was unsuccessful in some cases. Although partial replacement of an internal gene has been successful for generation of highly productive and mammalian nonpathogenic recombinant viruses, complete replacement of internal genes may be more favorable. In this study, we successfully generated complete recombinant H9N2 AIVs possessing 8 genomes of H9N2 AIVs by optimal combinations of 3' end promoter sequences of polymerase genomes, and a NS genome. All the generated recombinant viruses showed highly productive and mammalian nonpathogenic traits but some of them showed much higher virus titers in embryonated chicken eggs. Additionally, we found the same mutations of NS1 gene determined pathogenicity of AIVs in chicken embryos as well as mammals. Thus, the 3' end promoter optimization, and highly productive and mammalian nonpathogenic internal genes may be useful to develop vaccines against AIVs.

Acquisition of Innate Inhibitor Resistance and Mammalian Pathogenicity During Egg Adaptation by the H9N2 Avian Influenza Virus

An H9N2 avian influenza A virus (AIV), A/chicken/Korea/01310/2001 (01310-CE20), was established after 20 passages of influenza A/chicken/Korea/01310/2001 (01310-CE2) virus through embryonated chicken eggs (ECEs). As a result of this process, the virus developed highly replicative and pathogenic traits within the ECEs through adaptive mutations in hemagglutinin (HA: T133N, V216G, and E439D) and neuraminidase (NA: 18-amino acid deletion and E54D). Here, we also established that 01310-CE20 acquired resistance to innate inhibitors present in the egg white during these passages. To investigate the role of egg-adapted mutations in resistance to innate inhibitors, we generated four PR8-derived recombinant viruses using various gene combinations of HA and NA from 01310-CE2 and 01310-CE20 (rH₂N₂, rH₂N₂₀, rH₂₀N₂, and rH₂₀N₂₀). As expected, rH₂₀N₂₀ showed significantly higher replication efficiency in MDCK cells and mouse lungs, and demonstrated greater pathogenicity in mice. In addition, rH₂₀N₂₀ showed higher resistance to innate inhibitors than the other viruses. By using a loss-of-function mutant and receptor-binding assay, we demonstrated that a T133N site directed mutation created an additional N-glycosite at position 133 in rH₂₀N₂₀. Further, this mutation played a crucial role in viral replication and resistance to innate inhibitors by modulating the binding affinities to avian-like and mammalian-like receptors on the host cells and inhibitors. Thus, egg-adapted HA and NA may exacerbate the mammalian pathogenicity of AIVs by defying host innate inhibitors as well as by increasing replication efficiency in mammalian cells.

Novel mutations in avian PA in combination with an adaptive mutation in PR8 NP exacerbate the virulence of PR8-derived recombinant influenza A viruses in mice

The polymerase complex of the low-pathogenic avian influenza virus [A/chicken/Korea/KBNP-0028/2000] (0028) has previously been characterized, and novel amino acid residues present in the polymerase acidic protein (PA) that likely contribute to pathogenicity toward mammals have been identified. In the present study, our aims were to generate A/Puerto Rico/8/34 (PR8)-derived recombinant viruses containing the 0028-PA gene with a single amino acid mutation and to test their pathogenicity and replication ability. We found that the recombinant viruses acquired additional single mutations in the nucleoprotein (NP). Because the additional mutations in NP did not affect viral pathogenicity, but rather attenuated viral replication and polymerase activity, the incompatibility of the avian PA gene within the PR8 backbone may have induced an adaptive mutation in NP. To minimize the differences due to NP mutations, we generated 0028-PA mutants with an E375G mutation, not affecting viral replication and pathogenicity, in the NP gene. The PR8-PA(0028)-E684G mutant showed significantly higher viral replication in mammalian cells as compared to PR8-PA(0028) and led to 100% mortality in mice, with significantly increased interferon β expression. Thus, the E684G mutation in the PA gene may play an important role in viral pathogenicity in mice by increasing viral replication and the host immune response.

Optimized clade 2.3.2.1c H5N1 recombinant-vaccine strains against highly pathogenic avian influenza

A/Puerto Rico/8/34 (PR8)-derived recombinant viruses have been used for seasonal flu vaccines; however, they are insufficient for vaccines against some human-fatal H5N1 highly pathogenic avian influenza (HPAI) viruses (HPAIV) due to low productivity. Additionally, the polymerase basic 2 (PB2) protein, an important mammalian-pathogenicity determinant, of PR8 possesses several mammalian-pathogenic mutations. We previously reported two avian PB2 genes (01310 and 0028) related to efficient replication in embryonated chicken eggs (ECEs) and nonpathogenicity in BALB/c mice. In this study, we generated PR8-derived H5N1 recombinant viruses harboring hemagglutinin (attenuated) and neuraminidase genes of a clade 2.3.2.1c H5N1 HPAIV (K10-483), as well as the 01310 or 0028 PB2 genes, and investigated their replication and immunogenicity. Compared with a control virus harboring six internal PR8 genes (rK10-483), the recombinant viruses possessing the 01310 and 0028 PB2 genes showed significantly higher replication efficiency in ECEs and higher antibody titers in chickens. In contrast to rK10-483, none of the viruses replicated in BALB/c mice, and all showed low titers in Madin-Darby canine kidney cells. Additionally, the recombinant viruses did not induce a neutralization antibody but elicited decreased protective immune responses against K10-483 in mice. Thus, the highly replicative and mammalian nonpathogenic recombinant H5N1 strains might be promising vaccine candidates against HPAI in poultry.

Prerequisites for the acquisition of mammalian pathogenicity by influenza A virus with a prototypic avian PB2 gene

The polymerase of avian influenza A virus (AIV) is a heterotrimer composed of PB2, PB1, and PA. PB2 plays a role in overcoming the host barrier; however, the genetic prerequisites for avian PB2 to acquire mammalian pathogenic mutations have not been well elucidated. Previously, we identified a prototypic avian PB2 that conferred non-replicative and non-pathogenic traits to a PR8-derived recombinant virus when it was used to infect mice. Here, we demonstrated that key amino acid mutations (I66M, I109V, and I133V, collectively referred to as MVV) of this prototypic avian PB2 increase the replication efficiency of recombinant PR8 virus carrying the mutated PB2 in both avian and mammalian hosts. The MVV mutations caused no weight loss in mice, but they did allow replication in infected lungs, and the viruses acquired fatal mammalian pathogenic mutations such as Q591R/K, E627K, or D701N in the infected lungs. The MVV mutations are located at the interfaces of the trimer and are predicted to increase the strength of this structure. Thus, gaining MVV mutations might be the first step for AIV to acquire mammalian pathogenicity. These results provide new insights into the evolution of AIV in birds and mammals.

Lentivirus pre-packed with Cas9 protein for safer gene editing

The CRISPR/Cas9 system provides an easy way to edit specific site/s in the genome and thus offers tremendous opportunity for human gene therapy for a wide range of diseases. However, one major concern is off-target effects, particularly with long-term expression of Cas9 nuclease when traditional expression methods such as via plasmid/viral vectors are used. To overcome this limitation, we pre-packaged Cas9 protein (Cas9P LV) in lentiviral particles for transient exposure and showed its effectiveness for gene disruption in cells, including primary T cells expressing specific single guide RNAs (sgRNAs). We then constructed an 'all in one virus' to express sgRNAs in association with pre-packaged Cas9 protein (sgRNA/Cas9P LV). We successfully edited CCR5 in TZM-bl cells by this approach. Using an sgRNA-targeting HIV long terminal repeat, we also were able to disrupt HIV provirus in the J-LAT model of viral latency. Moreover, we also found that pre-packaging Cas9 protein in LV particle reduced off-target editing of chromosome 4:-29134166 locus by CCR5 sgRNA, compared with continued expression from the vector. These results show that sgRNA/Cas9P LV can be used as a safer approach for human gene therapy applications.

Models for Estimating Genetic Parameters of Milk Production Traits Using Random Regression Models in Korean Holstein Cattle

The objectives of the study were to estimate genetic parameters for milk production traits of Holstein cattle using random regression models (RRMs), and to compare the goodness of fit of various RRMs with homogeneous and heterogeneous residual variances. A total of 126,980 test-day milk production records of the first parity Holstein cows between 2007 and 2014 from the Dairy Cattle Improvement Center of National Agricultural Cooperative Federation in South Korea were used. These records included milk yield (MILK), fat yield (FAT), protein yield (PROT), and solids-not-fat yield (SNF). The statistical models included random effects of genetic and permanent environments using Legendre polynomials (LP) of the third to fifth order (L3–L5), fixed effects of herd-test day, year-season at calving, and a fixed regression for the test-day record (third to fifth order). The residual variances in the models were either homogeneous (HOM) or heterogeneous (15 classes, HET15; 60 classes, HET60). A total of nine models (3 orders of polynomials×3 types of residual variance) including L3-HOM, L3-HET15, L3-HET60, L4-HOM, L4-HET15, L4-HET60, L5-HOM, L5-HET15, and L5-HET60 were compared using Akaike information criteria (AIC) and/or Schwarz Bayesian information criteria (BIC) statistics to identify the model(s) of best fit for their respective traits. The lowest BIC value was observed for the models L5-HET15 (MILK; PROT; SNF) and L4-HET15 (FAT), which fit the best. In general, the BIC values of HET15 models for a particular polynomial order was lower than that of the HET60 model in most cases. This implies that the orders of LP and types of residual variances affect the goodness of models. Also, the heterogeneity of residual variances should be considered for the test-day analysis. The heritability estimates of from the best fitted models ranged from 0.08 to 0.15 for MILK, 0.06 to 0.14 for FAT, 0.08 to 0.12 for PROT, and 0.07 to 0.13 for SNF according to days in milk of first lactation. Genetic variances for studied traits tended to decrease during the earlier stages of lactation, which were followed by increases in the middle and decreases further at the end of lactation. With regards to the fitness of the models and the differential genetic parameters across the lactation stages, we could estimate genetic parameters more accurately from RRMs than from lactation models. Therefore, we suggest using RRMs in place of lactation models to make national dairy cattle genetic evaluations for milk production traits in Korea.

A genome-wide analysis of the ultimate pH in swine

Meat pH is an important factor influencing meat quality traits in swine. This study evaluated a large number of genetic variants that covered all of the swine chromosomal regions. Approximately 68,000 single nucleotide polymorphisms (SNPs), found on Illumina Porcine SNP chips, were tested for associations with meat pH values. A genome-wide association study (GWAS) found that 19 SNPs on Sus scrofa chromosome 4 were significantly associated with pH. Two major candidate genomic regions were defined: a 1.08-Mb region (at nucleotide 30118313 to 31207050) contained 10 significant SNPs, based on an effect value of 5.0; and a 2.7-Mb genomic region (at nucleotide 73293076 to 76023681) contained 9 significant SNPs. Three putative genes--PKHD1L1, VCPIP1, and LOC102166532--were identified by GWAS near significant SNPs. These genes may account for variations in pH levels. Three pseudogenes and two non-coding RNAs were also detected by GWAS analysis. Estimations of expected and observed P values for pH revealed significant departures from the null hypothesis. A total of 9 haplotype blocks (HB) were constructed: HBs 1, 3, and 5 showed significant effects on pH24 and pH45, whereas an association was not confirmed between pH24 and HBs 4, 6, and 8. Findings from this study indicate that the three genes identified may influence pH of pig meat.

Estimation of Genetic Associations between Production and Meat Quality Traits in Duroc Pigs

Data collected from 690 purebred Duroc pigs from 2009 to 2012 were used to estimate the heritability, and genetic and phenotypic correlations between production and meat quality traits. Variance components were obtained through the restricted maximum likelihood procedure using Wombat and SAS version 9.0. Animals were raised under the same management in five different breeding farms. The average daily gain, loin muscle area (LMA), backfat thickness (BF), and lean percent (LP) were measured as production traits. Meat quality traits included pH, cooking loss, lightness (L*), redness (a*), yellowness (b*), marbling score (MS), moisture content (MC), water holding capacity (WHC), and shear force. The results showed that the heritability estimates for meat quality traits varied largely from 0.19 to 0.79. Production traits were moderate to highly heritable from 0.41 to 0.73. Genotypically, the BF was positively correlated (p<0.05) with MC (0.786), WHC (0.904), and pH (0.328) but negatively correlated with shear force (−0.533). The results of genetic correlations indicated that selection for less BF could decrease pH, moisture content, and WHC and increase the shear force of meat. Additionally, a significant positive correlation was recorded between average daily gain and WHC, which indicates pork from faster-growing animals has higher WHC. Furthermore, selection for larger LMA and LP could increase MS and lightness color of meat. The meat quality and production traits could be improved simultaneously if desired. Hence, to avoid further deterioration of pork characteristics, appropriate selection of traits should be considered.

Novel reassortant influenza A(H5N8) viruses among inoculated domestic and wild ducks, South Korea, 2014

An outbreak of highly pathogenic avian influenza, caused by a novel reassortant influenza A (H5N8) virus, occurred among poultry and wild birds in South Korea in 2014. The aim of this study was to evaluate the pathogenesis in and mode of transmission of this virus among domestic and wild ducks. Three of the viruses had similar pathogenicity among infected domestic ducks: the H5N8 viruses were moderately pathogenic (0%-20% mortality rate); in wild mallard ducks, the H5N8 and H5N1 viruses did not cause severe illness or death; viral replication and shedding were greater in H5N8-infected mallards than in H5N1-infected mallards. Identification of H5N8 viruses in birds exposed to infected domestic ducks and mallards indicated that the viruses could spread by contact. We propose active surveillance to support prevention of the spread of this virus among wild birds and poultry, especially domestic ducks.

Effect of alcohol fermented feed on lactating performance, blood metabolites, milk Fatty Acid profile and cholesterol content in holstein lactating cows

A feeding experiment with 40 lactating Holstein cows and 4 dietary treatments was conducted to investigate supplementation with different levels of alcohol fermented feed to the TMR on lactating performance, blood metabolites, milk fatty acid profile and cholesterol concentration of blood and milk. Forty Holstein lactating cows (106±24 d post-partum; mean±SD) were distributed into four groups and randomly assigned to one of four treatments with each containing 10 cows per treatment. The treatment supplemented with TMR (DM basis) as the control (CON), and CON mixed with alcohol-fermented feeds (AFF) at a level of 5%, 10% and 15% of the TMR as T1, T2 and T3, respectively. Dry matter intake and milk yield were not affected by supplementation of AFF. An increased 4% FCM in the milk occurred in cows fed T3 diet compared with CON, while T1 and T2 diets decreased 4% FCM in a dose dependent manner. Supplementation of AFF increased the concentration of albumin, total protein (TP), ammonia, and high density lipoprotein-cholesterol in serum compared with CON. In contrast, supplementation with AFF clearly decreased concentration of blood urea nitrogen (BUN) and total cholesterol (TC) compare with CON. AFF supplementation increased the proportion of C18:1n9 and C18:2n6 compared to CON. A decrease in the concentration of saturated fatty acid (SFA) for T1, T2 and T3 resulted in an increased unsaturated fatty acid (USFA) to SFA ratio compared to CON. Concentration of cholesterol in milk fat was reduced in proportion to the supplemental level of AFF. Feeding a diet supplemented with a moderate level AFF to lactating cows could be a way to alter the feed efficiency and fatty acid profile of milk by increasing potentially human consumer healthy fatty acid without detrimental effects on feed intake and milk production. A substantially decreased cholesterol proportion in milk induced by supplementation AFF suggests that alcohol fermented feed may improve milk cholesterol levels without any negative effects in lactating cows.

Supplementation of influenza split vaccines with conserved M2 ectodomains overcomes strain specificity and provides long-term cross protection

Current influenza vaccines do not provide good protection against antigenically different influenza A viruses. As an approach to overcome strain specificity of protection, this study demonstrates significantly improved long-term cross protection by supplementing split vaccines with a conserved molecular target, a repeat of the influenza M2 ectodomain (M2e) expressed on virus-like particles (M2e5x VLPs) in a membrane-anchored form. Intramuscular immunization with H1N1 split vaccine (A/California/07/2009) supplemented with M2e5x VLPs induced M2e-specific humoral and cellular immune responses, and shaped the host responses to the vaccine in the direction of T-helper type 1 responses inducing dominant IgG2a isotype antibodies as well as interferon-γ (IFN-γ) producing cells in systemic and mucosal sites. Upon lethal challenge, M2e5x VLP-supplemented vaccination lowered lung viral loads and induced long-term cross protection against H3N2 or H5N1 subtype influenza viruses over 12 months. M2e antibodies, CD4 T cells, and CD8 T cells were found to contribute to improving heterosubtypic cross protection. In addition, improved cross protection by supplemented vaccination with M2e5x VLPs was mediated via Fc receptors. The results support evidence that supplementation with M2e5x VLPs is a promising approach for overcoming the limitation of strain-specific protection by current influenza vaccination.

Pathogenicity in domestic ducks and mice of highly pathogenic H5N1 clade 2.3.2.1 influenza viruses recently circulating in Eastern Asia

Influenza virus A (H5N1) clade 2.3.2.1 has recently caused widespread outbreaks of disease in domestic poultry and wild birds in Eastern Asia. In the current study, the antigenicity and pathogenicity of three clade 2.3.2.1 viruses (Ck/Kr/Gimje/08, Ws/Mongolia/1/09, and Ws/Mongolia/7/10) were investigated in domestic ducks and mice. The H5N1 influenza viruses in this study were antigenically similar to each other (r-values of 0.35-1.4). The three viruses replicated systemically in all tissues tested in domestic ducks, indicating high pathogenicity. However, the viruses produced different clinical signs and mortality rates: Ck/Kr/Gimje/08 and Ws/Mongolia/1/09 resulted in 100% mortality with severe neurological signs, whereas Ws/Mongolia/7/10 resulted in 50% mortality with relatively mild neurological signs. In mice, infection with Ck/Kr/Gimje/08 and Ws/Mongolia/7/10 resulted in weight loss that peaked at 4 days post-infection (22.3% and 20.8%, respectively), same MLD50 (2.2 Log10 EID50) and systemic replication. The three viruses had K deletion at the -2 position of the HA1-connecting peptide (PQRERRRK-R), which is associated with increased virulence in domestic ducks and harbored NA stalk deletion, NS1 deletion and mutation of P42S in NS1, and full length (90aa) in PB1-F2, which confer increased virulence in mice. Our study shows that clade 2.3.2.1 viruses from Korea and Mongolia are antigenically similar and highly pathogenic in both domestic ducks and mice. Moreover, we provide molecular determinants of the clade 2.3.2.1 viruses associated with the pathogenicity in domestic ducks and mice, respectively.

Effects of different polymerases of avian influenza viruses on the growth and pathogenicity of A/Puerto Rico/8/1934 (H1N1)-derived reassorted viruses

We generated reassorted PR8 viruses containing six different combinations of avian influenza virus (AIV) polymerase genes from A/chicken/Korea/01310/2001 (H9N2) (01310) and A/chicken/Korea/KBNP-0028/2000 (H9N2) (0028) to examine the effects of the AIV polymerase genes PB1, PB2, and PA on replication efficiency in different host cells and pathogenicity in mice. The virus titers of the reassorted viruses possessing 01310 [rPR8-PB2(01310)] and 0028 [rPR8-PB2(0028)] PB2 genes were significantly higher than those of the others except the rPR8 virus in embryonated chicken eggs at 37°C, and those of avian polymerase reassorted viruses were significantly less than rPR8 in MDCK cells at 32 and 37°C. rPR8-PB2(01310), rPR8-PB2(0028), and rPR8-PA(0028) caused no body weight loss in BALB/c mice but rPR8-PA(01310), rPR8-PB1(01310), and rPR8-PB1(0028) caused mortality and significantly different body weight loss compared to those in the mock treatment. In contrast to rPR8-PB2(0028) and rPR8-PA(0028), rPR8-PB2(01310) was not isolated from infected mice, and rPR8-PB1(0028) was less pathogenic than rPR8-PB1(01310). We determined the amino acid residues that were specific to the less pathogenic polymerases. A comparison with those of pandemic 2009 H1N1, human fatal H5N1 and H7N9, and pathogenic AIVs to mice without adaptation revealed that they possessed the mammalian pathogenic constellation of polymerases. Thus, the novel polymerase genes and amino acid residues may be useful to understand the host-barrier overcome of AIVs in mice and to develop safer and efficacious vaccines.

Curcumin decreases oleic acid-induced lipid accumulation via AMPK phosphorylation in hepatocarcinoma cells

BACKGROUND AND OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is one of the most common metabolic syndromes and is characterized by the accumulation of hepatic triglycerides (TG), which result from an imbalance between uptake, synthesis, export, and oxidation of fatty acids. Curcumin is a polyphenol derived from the herbal remedy and dietary spice turmeric, was found to prevent obesity and diabetes in mouse models. However, a hypolipidemic effect of curcumin in oleic acid- induced hepatocarcinoma cells has not been reported. In this study, we examined the effect of curcumin on reducing lipid accumulation in hepatic cells.

MATERIALS AND METHODS

Hepatocytes were treated with oleic acid (OA) containing with or without curcumin to observe the lipid accumulation by Oil Red O stain. We also tested the effects of curcumin on triglycerides (TG) and total cholesterol (TC) in HepG2 cells. Western blot and reverse transcription polymerase chain reaction (RT-PCR) was used to measure sterol regulatory element binding proteins-1 (SREBP-1), fatty acid synthase (FAS), peroxisome proliferator-activated receptor (PPAR)-α, and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) expression.

RESULTS

Curcumin suppressed OA-induced lipid accumulation and TG and TC levels. Also, curcumin decreased hepatic lipogenesis such as SREBP-1, and FAS. Besides, we also found out the antioxidative effect of curcumin by increasing the expression of PPARα. Curcumin increased AMPK phosphorylation in hepatocytes.

CONCLUSIONS

These results indicated that curcumin has the same ability to activate AMPK and then reduce SREBP-1, and FAS expression, finally leading to inhibit hepatic lipogenesis and hepatic antioxidative ability. In this report, we found curcumin exerted a regulatory effect on lipid accumulation by decreasing lipogenesis in hepatocyte. Therefore, curcumin extract may be active in the prevention of fatty liver.

Geographical distribution of low pathogenic avian influenza viruses of domestic poultry in Vietnam and their genetic relevance with Asian isolates

From the avian influenza virus (AIV) outbreaks and market surveillances in Vietnam during November 2011 and March 2012, a total of 196 AIV were isolated. Although H5N1 highly pathogenic avian influenza (HPAI) was the most prevalent subtype in Vietnam, 57 low pathogenic avian influenza (LPAI) viruses were identified from mainly domestic ducks and some chickens. Of note, various subtypes of LPAI viruses were isolated from domestic ducks in Vietnam: H3 (n = 16), H4 (n = 4), H6 (n = 24), H7 (n = 1), and H9 (n = 10). Geographically, the LPAI viruses were identified in different regions of Vietnam. Phylogenetic analysis of HA and NA genes in LPAIV in Vietnam showed that some H3 (group I) and H4 subtypes AIV clustered with the viruses of several Asian isolates from domestic poultry and wild birds. However, the H6, H9, and some H3 (group II and III) subtypes AIV were closely related to isolates from domestic poultry in Southern China. In addition, whereas the N2 and N6 subtypes AIV belonged to the Eurasian lineage, the N8 subtype AIV was classified to be both of Eurasian and American lineage. These findings revealed that the regional trade and wild birds play a key role transmission of LPAIV in domestic ducks in Vietnam. Further surveillance at the intercountry level is needed to understand the epidemiology of these viruses and to cope with emergence of novel AIV types.

Multiple heterologous M2 extracellular domains presented on virus-like particles confer broader and stronger M2 immunity than live influenza A virus infection

The influenza M2 ectodomain (M2e) is poorly immunogenic and has some amino acid changes among isolates from different host species. We expressed a tandem repeat construct of heterologous M2e sequences (M2e5x) derived from human, swine, and avian origin influenza A viruses on virus-like particles (M2e5x VLPs) in a membrane-anchored form. Immunization of mice with M2e5x VLPs induced protective antibodies cross-reactive to antigenically different influenza A viruses and conferred cross protection. Anti-M2e antibodies induced by heterologous M2e5x VLPs showed a wider range of cross reactivity to influenza A viruses at higher levels than those by live virus infection, homologous M2e VLPs, or M2e monoclonal antibody 14C2. Fc receptors were found to be important for mediating protection by immune sera from M2e5x VLP vaccination. The present study provides evidence that heterologous recombinant M2e5x VLPs can be more effective in inducing protective M2e immunity than natural virus infection and further supports an approach for developing an effective universal influenza vaccine.

Molecular epidemiological investigation of velogenic Newcastle disease viruses from village chickens in Cambodia

Three isolates of Newcastle disease virus (NDV) were isolated from tracheal samples of dead village chickens in two provinces (Phnom Penh and Kampong Cham) in Cambodia during 2011-2012. All of these Cambodian NDV isolates were categorized as velogenic pathotype, based on in vivo pathogenicity tests and F cleavage site motif sequence ((112)RRRKRF(117)). The phylogenetic analysis and the evolutionary distances based on the sequences of the F gene revealed that all the three field isolates of NDV from Cambodia form a distinct cluster (VIIh) together with three Indonesian strains and were assigned to the genotype VII within the class II. Further phylogenetic analysis based on the hyper-variable region of the F gene revealed that some of NDV strains from Malaysia since the mid-2000s were also classified into the VIIh virus. This indicates that the VIIh NDVs are spreading through Southeast Asia. The present investigation, therefore, emphasizes the importance of further surveillance of NDV in neighboring countries as well as throughout Southeast Asia to contain further spreading of these VIIh viruses.

Characterization of mutations associated with the adaptation of a low-pathogenic H5N1 avian influenza virus to chicken embryos

Migratory waterfowls are the most common reservoir for avian influenza virus (AIV), thus viral adaptation is required for efficient replication in land fowls. To date, low pathogenic (LP) H5 subtype AIVs have been isolated from migratory waterfowls, and the adaptation of these viruses to land fowls might lead to the generation of highly pathogenic AIVs. Thus, A/wild duck/Korea/50-5/2009 (H5N1) LPAIV was passaged 20 times through embryonated chicken eggs (ECEs), and the resulting genetic and phenotypic changes were investigated. The pathogenicities of the early (50-5-E2) and final passage (50-5-E20) strains to chicken embryos were similarly high, but the 50-5-E20 titer was 100 times higher than that of 50-5-E2. 50-5-E20 showed 8 amino acid changes in PA (1), HA (4), NA (1), M1 (1) and M2 (1), with different frequencies among influenza A viruses (0-99.6%). The relevance of these changes, except H103Y in HA, to viral replication remains unknown. To investigate the roles of internal genes and mutations in HA and NA in viral replication, four recombinant viruses possessing combinations of HA and NA genes of 50-5-E2 and 50-5-E20 with 6 internal genes of PR8 were generated through reverse genetics. The embryo pathogenicities of the H5N1 recombinant viruses carrying internal PR8 genes were reduced, and the titers of the recombinant viruses with 50-5-E20 HA were higher than those with 50-5-E2 HA. Therefore, the identified mutations might be useful as chicken adaptation markers for the generation of high growth H5N1 recombinant viruses in ECEs.

Genetic and antigenic characteristics of H4 subtype avian influenza viruses in Korea and their pathogenicity in quails, domestic ducks and mice

In Korea, a nationwide surveillance programme was implemented in 2003 to identify highly pathogenic avian influenza viruses (AIVs). AIVs belonging to one of the most common haemagglutinin subtypes, H4, were isolated from two domestic ducks and 52 wild birds between 2004 and 2010. These H4 AIVs could be further classified into three neuraminidase subtypes: H4N6 (94.4%), H4N2 (3.7%) and H4N3 (1.9%). Phylogenetic analysis revealed that the H4 AIVs had a variety of genetic constellations, with at least nine different genotypes represented. The pathogenicity of these H4 viruses was assessed in quails, domestic ducks and mice. None of the H4 AIVs induced clinical signs in quails or domestic ducks. Viral shedding in quails was relatively high, and virus was recovered up to 5-7 days post-inoculation (p.i.) in oropharyngeal swabs, but the viruses replicated poorly in domestic ducks. Quails may act as an intermediate host in which AIVs are amplified and transmitted to other species. In mice, all of the AIVs were recovered efficiently at relatively high titres from the lungs up to 7 days p.i., demonstrating the potential for AIVs to infect mice directly without prior adaptation. None of the AIVs induced clinical signs nor was any lethal to infected mice. However, there was significant loss of body weight in mice infected with viruses of duck origin. It is suggested that the active surveillance of influenza viruses needs to be enhanced in domestic poultry as well as in wild birds, and that it should include assessment of pathogenicity in animal models.

Isolation of a reassortant H13N2 virus from a mallard fecal sample in South Korea

Background

Virus subtype H13N2, A/mallard/Kr/SH38-45/2010 (H13N2), was first isolated from a mallard fecal sample in South Korea.

Results

Phylogenetic analysis of all eight viral genes revealed that this virus emerged by genetic mixing between Eurasian and North American gene pools, and possibly between wild ducks and gulls. The H13 and N2 surface genes clustered together in a group with Eurasian isolates from gulls and wild birds, respectively. The PB2, PA, NP, M and NS segments belonged to the Eurasian lineage, whereas the PB1 gene clustered in the North American lineage. Furthermore, they showed a bird-dependent pattern in phylogenetic analysis: the M gene was similar to subtype H13 viruses within gulls, whereas other segments were similar to avian influenza viruses of other subtypes from wild ducks.

Conclusions

The data suggests that the novel reassortant H13N2 virus isolated in South Korea might have emerged by genetic reassortment between intercontinental and interspecies transmission in wild birds.

Highly pathogenic avian influenza (H5N1) outbreaks in wild birds and poultry, South Korea

Highly pathogenic avian influenza (H5N1) among wild birds emerged simultaneously with outbreaks in domestic poultry in South Korea during November 2010–May 2011. Phylogenetic analysis showed that these viruses belonged to clade 2.3.2, as did viruses found in Mongolia, the People’s Republic of China, and Russia in 2009 and 2010.

Anti-inflammatory effects of Hylomecon hylomeconoides in RAW 264.7 cells

BACKGROUND AND OBJECTIVES

Papaveraceae serve as a rich source of various alkaloids which have anti-inflammatory effect.

MATERIALS AND METHODS

In this study, we investigated the effect of Hylomecon hylomeconoides ethanol extract (HHE) on lipopolysaccharide (LPS)-induced NO and interleukin-6 (IL-6) production in RAW 264.7 cells.

RESULTS

HHE inhibited LPS-induced NO and IL-6 production. Moreover, HHE suppressed the phosphorylation of ERK1/2 and p38 in LPS-induced RAW 264.7 in a dose-dependent manner. Furthermore, major constituents, dihydrosanguinarine and 6-methoxydihydrosanguinarine, of the chloroform-soluble extract were analyzed.

CONCLUSIONS

Taken together, the results of this study indicate that the anti-inflammatory effects of HHE may occur via the inhibition of NO and IL-6 expression through the down-regulation of MAP kinase (ERK1/2, p38) phosphorylation in RAW 264.7 cells.

Antibacterial activity of bark of Alnus pendula against methicillin-resistant Staphylococcus aureus

BACKGROUND AND OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a rapidly growing health problem around the globe. Recently, there has been considerable interest in the use of plant materials as an alternative method to control pathogenic microorganisms. In this study we evaluated the antibacterial activity of bark of Alnus pendula against MRSA.

MATERIALS AND METHODS

The MIC determination was done using the microdilution broth method and bacterial growth was determined by measuring optical density using spectrophotometer.

RESULTS

Alnus pendula bark EtOH extract and fractions (F-1, -2, -3 and -4) were investigated against MRSA. The most active fractions (F-3 and F-4) led to the isolation of oregonin (ORE) and hirsutanone (HIR). These compounds were active against MRSA strains with minimum inhibitory concentrations (MICs) ranging from 31.25 to 250 microg/ml MIC and 2 MIC of HIR completely inhibited the growth of MRSA.

CONCLUSIONS

The bark EtOH extract of Alnus Pendula has potent antibacterial activity against MRSA.

Low pathogenic H7 subtype avian influenza viruses isolated from domestic ducks in South Korea and the close association with isolates of wild birds

We characterized low pathogenic avian influenza (LPAI) viruses of the H7 subtype that were isolated from domestic ducks and wild birds in South Korea from 2008 to 2011. A total of 20 H7 viruses were collected from live-bird markets (LBMs), duck farms and wild-bird habitats using avian influenza (AI) surveillance and epidemiological approaches. A phylogenetic analysis of the H7 viruses that were isolated from domestic ducks and wild birds demonstrated that they were separated into 12 genotypes (A-D and Wb-1-8, respectively), indicating genetic diversity. These H7 viruses were related to the recently isolated Eurasian LPAI H7 viruses and various influenza viruses that are circulating in Asia, including southern China and South Korea. The same genotype was not found between domestic poultry and wild-bird isolates; however, most of the H7 viruses in poultry (genotypes B and C) were closely related to the H7 virus isolated from a wild bird (genotype Wb-3). Animal-challenge studies revealed that certain H7 AI viruses replicated well only in chickens or ducks depending on the genotype, indicating that the pathogenicity of H7 viruses has the potential to be altered due to multiple reassortments, and these viruses can potentially expand their host range. Our results are evidence of abundant and frequent reassortment between H7 viruses in poultry and wild birds and emphasize the continuing need to monitor the evolutionary genetics of the influenza virus in poultry and wild birds.

H5N1 subtype highly pathogenic avian influenza virus isolated from healthy mallard captured in South Korea

On December 7, 2010, H5N1 highly pathogenic avian influenza virus was isolated from a healthy mallard captured at the Mankyung River in South Korea. Phylogenetic analysis showed that this virus was classified into clade 2.3.2 and closely related to H5N1 viruses isolated from wild birds in Mongolia, Russia and China in 2009 and 2010.

Survival rate of H5N1 highly pathogenic avian influenza viruses at different temperatures

The survival rate of Korean H5N1 highly pathogenic avian influenza (HPAI) viruses was investigated at different temperatures under the laboratory conditions. The estimated survival days for a starting viral concentration of 10(6.5) 50% egg infectious dose/0.1 mL were 930, 1,042, and 3,213 d at 4 degrees C; 226, 232, and 293 d at 20 degrees C; and 51, 55, and 58 d at 30 degrees C for A/chicken/Korea/ES/03, A/chicken/Korea/IS/06, and A/chicken/Korea/Gimje/08 (Gimje/08) viruses, respectively. The stability of the Gimje/08 virus was statistically significant compared with the other 2 viruses except for the data between Gimje/08 and A/chicken/Korea/IS/06 virus at 30 degrees C. This result indicated that the survival rate of 3 Korean HPAI viruses is different at various temperatures, which might have partially influenced the large scale of HPAI outbreak in Korea in 2008.

Antimicrobial activity of the constituents of Smallanthus sonchifolius leaves against methicillin-resistant Staphylococcus aureus

BACKGROUND AND OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) has been a serious problem as its infection is associated with higher mortality and increase cost worldwide. In the present study, the antibacterial activity of enhydrin, polymatin B, allo-schkuhriolide from the leaves of Smallanthus sonchifolius was investigated.

MATERIAL AND METHODS

Enhydrin, polymatin B, allo-schkuhriolide from the leaves of Smallanthus sonchifolius were tested for antimicrobial activity using micro dilution broth method against 2 strains of ATCC 33591, ATCC 25923 and 15 strains of clinical isolates MRSA.

RESULTS

The antibacterial activity of Smallanthus sonchifolius can safely be attributed to enhydrin as polymatin B, and allo-schkuhriolide are not showing any activity against Staphylococcus aureus strains. The enhydrin showed good antibacterial activity against all tested strains (MIC = 125-500 microg/ml).

DISCUSSION

These results suggest that only enhydrin can be considered as an antibacterial drug against MRSA.

Characterization of H5N2 influenza viruses isolated in South Korea and their influence on the emergence of a novel H9N2 influenza virus

We characterized low pathogenic avian influenza (LPAI) H5N2 and H9N2 viruses isolated in South Korea from 2008 to 2009. Genetic analysis of the H5N2 viruses isolated from wild birds and domestic ducks demonstrated that they were related to the recently isolated southern Chinese LPAI H5 viruses and various influenza viruses circulating in Eurasia. Three H9N2 viruses obtained at live bird markets and duck farms were reassortant viruses generated from the H5N2 viruses of domestic ducks and the H9N2 virus endemic in Korean chickens. The H5N2 viruses did not replicate well in experimentally infected chickens and mice, but novel H9N2 viruses, without pre-adaptation, were recovered at high titres in chickens. Our results show that reassortment between H5N2 and H9N2 viruses must have occurred in domestic ducks and may have contributed to the diversity expansion of the gene pool, which has potential to alter the pathogenicity and host range of the influenza virus.

Protection of chickens from Newcastle disease with a recombinant baculovirus subunit vaccine expressing the fusion and hemagglutininneuraminidase proteins

Recombinant baculoviruses containing the fusion (F) and hemagglutinin-neuraminidase (HN) glycoprotein gene of the viscerotropic velogenic (vv) Newcastle disease virus (NDV) isolate, Kr-005/00, and a lentogenic La Sota strain of the NDV were constructed in an attempt to develop an effective subunit vaccine to the recent epizootic vvNDV. The level of protection was determined by evaluating the clinical signs, mortality, and virus shedding from the oropharynx and cloaca of chickens after a challenge with vvNDV Kr-005/00. The recombinant ND F (rND F) and recombinant HN (rND HN) glycoproteins derived from the velogenic strain provided good protection against the clinical signs and mortality, showing a 0.00 PI value and 100% protection after a booster immunization. On the other hand, the combined rND F + HN glycoprotein derived from the velogenic strain induced complete protection (0.00 PI value and 100% protection) and significantly reduced the amount of virus shedding even after a single immunization. The rND F and rND HN glycoproteins derived from the velogenic strain had a slightly, but not significantly, greater protective effect than the lentogenic strain. These results suggest that the combined rND F + HN glycoprotein derived from vvNDV can be an ideal subunit marker vaccine candidate in chickens in a future ND eradication program.

Genetic diversity of avian infectious bronchitis virus isolates in Korea between 2003 and 2006

Thirty-three field isolates of avian infectious bronchitis virus (IBV) were recovered from commercial chicken flocks in Korea between 2003 and 2006 and were characterized phylogenetically by nucleotide sequence analysis of the IBV S1 gene hyper-variable region. Our phylogenetic analysis revealed that recent field isolates of IBV formed at least three distinct phylogenetic types, including K-I, K-II, and K-III. K-I type IBV consisted of indigenous, 13 IBV isolates which evolved from the Kr-EJ/95 strain and then separated into the lineages of type K-Ia and type K-Ib. K-II type IBV isolates (n = 19) were closely related to nephropathogenic IBV variants from China and Japan. The K-III type isolate (Kr/D064/05), first identified by this study, was closely related to enteric IBV variants from the Chinese strains that cause proventriculitis. Sequence comparisons showed amino acid differences of >27.5% between IBV types. The molecular epidemiologic characteristics of IBV field isolates are briefly discussed.

Bio-separation of toxic arsenate ions from dilute solutions by native and pretreated biomass of Aspergillus fumigatus in batch and column mode: effect of biomass pretreatment

The sorption of As(V) from aqueous solution onto live and pretreated biomass of Aspergillus fumigatus was studied. The studies on optimization of contact time, adsorbent dosage and pH showed that the FeCl(3) treated and FeSO(4) treated biomass had the maximum capacity to adsorb As(V) while acid treated biomass was found to be minimum. Adsorption parameters were determined using both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of 0.054 mg/g was observed in FeCl(3) treated and FeSO(4) treated biomasses. Column mode studies were conducted using FeSO(4) treated biomass to compare its efficacy with batch mode to adsorb As(V). Batch mode experiments proved to be efficient. Desorption studies were also carried out with dilute sodium hydroxide to recover both the adsorbent and adsorbate.

Organic micro-pollutant removal in liquid-phase using carbonized silk cotton hull

Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The present study was aimed at using silk cotton hull, a potent agricultural waste as an adsobent for removal of 2,4-dichlorophenol (2,4-DCP), which was used as a model phenolic compound. The process parameters were investigated and optimized conditions were determined. The equilibrium time was found to be 60 and 80 min for 10 and 20 mg/L and 100 min for 30 and 40 mg/L 2,4-DCP concentrations, respectively. Among the kinetic models applied, pseudo-second order model fitted well. The maximum adsorption capacity was 16.0 mg/g by Langmuir isotherm. Acidic pH was found favorable for the adsorption of 2,4-DCP. Studies on pH effect and desorption seemed to show that chemisorption played a major role in the adsorption process. In thermodynamic study, the change in entropy (DeltaS0) and heat of adsorption (DeltaH0) of silk cotton hull carbon (SCHC) was estimated as 14.01 J/(mol x K) and 3.04 kJ/mol, respectively. SCHC as adsorbent for removal of 2,4-DCP from aqueous solution, is effective, inexpensive, indigenous, reusable, has low treatment time and is easily available in large quantities as waste there by significantly lowers the cost of wastewater treatment.

Continuing evolution of H9 influenza viruses in Korean poultry

We analyzed the evolution of H9 influenza viruses isolated from Korean chicken farms from 2002 to 2004. Korean H9 viruses formed two antigenically distinct groups: those isolated from 1996 to mid-2003, and those isolated from late 2003 through 2004. Most of the 2004 isolates showed greater cross-reactivity with the second group than with the first group. Phylogenetic analysis of the 12 viruses studied revealed three genotypes of H9N2 viruses and showed that reassortment had occurred. One isolate, Ck/Kor/164/04, belonged to the H9N8 subtype. Its HA and PB1 genes were similar to those of the H9N2 viruses, but its other genes were closely related to H3N8 viruses. This report is the first (to our knowledge) of H9N8 infection in this host. The pathogenicity of the early isolates altered due to antigenic drift and reassortment, leading to H9 avian influenza viruses in Korea that potentially can expand their host range to mammalians.

Effects of Homologous and Heterologous Neuraminidase Vaccines in Chickens Against H5N1 Highly Pathogenic Avian Influenza

The 2004 Asian H5N1 epizootic outbreak indicates the urgent need for vaccines against highly pathogenic avian influenza (HPAI) virus. The manufacture of inactivated whole-virus vaccines from HPAI viruses by traditional methods is not feasible for safety reasons as well as technical issues. The low pathogenic avian influenza A/wild bird feces/CSM2/02 (H5N3) virus was used as a heterologous neuraminidase vaccine, and HPAI A/CK/Korea/ES/03 (H5N1) virus was used as a homologous neuraminidase vaccine. Protection efficacy of both vaccines was evaluated by clinical signs, mortality rates, and virus shedding from oropharynx and cloaca of vaccinated chickens after challenge with HPAI A/CK/Korea/ES/03 (H5N1) virus. One dose of 128 hemagglutinin (HA) homologous H5N1 vaccine induced 100% protection in mortality and prevented viral shedding completely after lethal dose virus challenge, whereas one dose of 64 HA unit of heterologous H5N3 vaccine only induced 50% protection in mortality, and it did not prevent viral shedding. However, two doses at a 3-wk interval of 64 HA unit of heterologous H5N3 vaccine as well as one dose of 1024 HA unit of heterologous H5N3 vaccine induced 100% survival rate and could prevent viral shedding completely. Furthermore, we could differentiate the sera of infected birds from those of vaccinated birds by indirect immunofluorescent antibody test. These results suggest that heterologous neuraminidase H5N3 vaccine could be a useful tool for the control of H5N1 HPAI epidemic in poultry.

Highly pathogenic avian influenza (H5N1) in the commercial domestic ducks of South Korea

The present study reports the clinical, virological and pathological findings observed in a natural outbreak of highly pathogenic avian influenza in farmed commercial ducks. The ducks developed clinical signs, including mild respiratory distress, depression, mild diarrhoea, loss of appetite and increasing mortality (up to 12%). At necropsy, multifocal mottled necrosis was commonly found in the pancreas with splenomegaly, hepatomegaly, and swollen kidneys. Microscopically, there was necrotized pancreatitis and hepatitis, and lymphocytic meningoencephalitis and myocarditis. Influenza viral antigen was demonstrated in areas closely associated with histopathological lesion. Avian influenza virus was isolated from the caecal tonsil, faeces, and kidney of the domestic ducks. The isolated virus was identified as a highly pathogenic H5N1, with a haemagglutinin proteolytic cleavage site deduced amino acid sequence of ... QREKRKKR/GLFGAIAG ... In order to determine the pathogenicity of the isolate, eight 6-week-old specific pathogen free chickens were inoculated intravenously with the virus, and all birds died within 24 h after inoculation. This is the first report of an outbreak of highly pathogenic avian influenza with clinical signs in commercial domestic ducks in South Korea.