Antiviral activity of Alpinia katsumadai extracts against rotaviruses

In vitro anti-rotavirus activity of Alpinia katsumadai (AK) extracts were evaluated against bovine G8P[7] and porcine G5P[7] rotaviruses in two different assay strategies, a mixed treatment assay and a post treatment assay. In the mixed treatment assay, six AK extracts [AK-1 (EtOH extract), AK-3 (H(2)O layer), AK-5 (40% methanol fraction), and AK-9-11 (H(2)O extract, polysaccharide fraction, supernatant fraction)] exhibited inhibitory activities against G5P[7] rotavirus with the EC(50) values ranging from 0.7±0.4 to 33.7±6.5 μg/mL. Extracts AK-1, AK-3, and AK-5 inhibited rotavirus infection against G8P[7] rotavirus, the with EC(50) values of 8.4±2.2 μg/mL, 6.5±0.8 μg/mL and 8.4±5.0 μg/mL, respectively. By hemagglutination inhibition (HI) assay, six AK extracts completely inhibited viral adsorption onto human RBCs in both strains of rotaviruses at less than 11 μg/mL. However, in the post treatment assay, there was no anti activity shown against both strains of rotaviruses. As a result, six AK extracts were attributed mainly to having a strong interaction with hemagglutinin protein on the outer surface of rotavirus, resulting to blockage of viral adsorption.     

The effect of bentonite concentration on the drug delivery efficacy of a pH-sensitive alginate/bentonite hydrogel

We produced a protein loaded, pH-sensitive alginate-bentonite hydrogel for wound dressings. Alginate is a nontoxic polysaccharide with favorable pH-sensitive properties that make it useful for the intestinal delivery of protein drugs. However, the use of alginate for drug delivery is limited by drug leaching and rapid dissolution of alginate at the higher pH, which may result in lower entrapment efficiency and a burst in the release of entrapped protein drugs. To overcome these problems, we created a novel cross-linked alginate-bentonite hydrogel by combining mineral-rich bentonite with the alginate matrix along with an additive to ensure controlled release. We analyzed the gel in the drug loading process in an aqueous environment by looking at the release profiles of a model protein drug (BSA) from the hydrogel at pH values of 4.5, 5.2 (skin area) and 7.4, 9.2 (wound area). The swelling ratio decreased with bentonite concentration, but did not fall below 6. The rate of drug release was slowest at a pH value of 4.5 and fastest at a pH value of 9.2. The rate of drug release decreased with bentonite concentration. The presence of bentonite prevents the rapid dissolution of alginate at the higher pH, ensuring the controlled release of the entrapped drug.     

Immunoprophylactic effect of chicken egg yolk immunoglobulin (Ig Y) against porcine epidemic diarrhea virus (PEDV) in piglets

Porcine epidemic diarrhea virus (PEDV) is the causative agent of neonatal diarrhea in piglets, which causes high mortality rates. In this study, the immunoprophylactic effects of chicken egg yolk immunoglobulin (Ig Y) against PEDV were investigated in neonatal pigs. Ig Y was found to reduce the mortality in piglets after challenge exposures. The field application of Ig Y also revealed significant differences in survival rates of piglets given Ig Y, as compared with placebo or control. The results in this study indicated that Ig Y against PEDV could be an alternative way of supplementing prophylactic measures like colostral antibodies from sows.     

Characteristics of the marine environment and algal blooms in Gamak Bay

This study was conducted to gain insight into the characteristics of algal blooms in relation to the marine environment of Gamak Bay. From the first known occurrence of algal blooms in 1984 until 2006, 23 causal species have been identified, the most common ones being Prorocentrum sp., Cochlodinium polykrikoides, Chaetoceros sp., Skeletonema costatum, and Heterosigma akashiwo. A principal component analysis indicated that blooms of these species develop under different conditions in terms of water temperature, salinity, precipitation, and insolation. Field data showed Cochlodinium polykrikoides to be favored by high temperatures and to be euryhaline, whereas Skeletonema costatum appeared to be eurythermal and euryhaline. Prorocentrum sp. and Chaetoceros sp. appeared to be stenothermal and stenohaline. Finally, Heterosigma akashiwo appeared at the lowest temperature and highest salinity of the five species and was classified here as stenothermal and stenohaline.     

Detection and molecular characterization of porcine type 3 orthoreoviruses circulating in South Korea

Orthoreoviruses infect virtually all mammalian species, causing systemic infections including mild gastrointestinal and respiratory illnesses. However, little is known about the prevalence or genetic diversity of porcine orthoreoviruses in South Korea. We examined 237 diarrheic fecal samples collected from 78 pig farms around the country. RT-PCR utilizing primers specific for the L1 gene of mammalian orthoreoviruses showed that 45 (19.0%) samples were positive. The 10 strains isolated from orthoreovirus-positive samples formed typical perinuclear cytoplasmic inclusion bodies and had an atypical hemagglutination pattern; these are characteristics of type 3 orthoreovirus. Phylogenetic analysis of the S1 gene in these 10 Korean and other strains showed that type 3 orthoreoviruses could be divided into four lineages; the 10 Korean strains were included in porcine lineage IV, along with T3/porcine/Sichuan/2006. Sequence analysis showed that strains in lineage IV had nucleotide identities of 97.0-98.1% and deduced amino acid identities of 96.4-98.2%. Sequence analysis of the σ1 protein, a viral attachment protein, revealed that the amino acid sequences associated with neurotropism (amino acids 198-204, 249I, 350D, and 419E) were highly conserved among the Korean strains, confirming that neural tropism was present. In conclusion, our findings suggest that porcine orthoreovirus infections are endemic in pig farms in South Korea and that the 10 novel Korean porcine orthoreoviruses belong to porcine lineage IV of type 3 orthoreovirus. In addition, sequence analysis of S1 genes encoding the σ1 protein showed that the 9 of 10 Korean porcine orthoreoviruses exhibited neural tropism.     

Prevalence of the enteroaggregative Escherichia coli heat-stable enterotoxin 1 gene and its relationship with fimbrial and enterotoxin genes in E. coli isolated from diarrheic piglets.

A total of 720 Escherichia coli strains isolated from diarrheic piglets on 756 swine farms were screened for the presence of the enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) gene by polymerase chain reaction (PCR). Escherichia coli strains that carried EAST1 genes were also tested by PCR for the presence of 4 fimbriae (F4, F5, F6, F41), 2 heat-stable enterotoxins (STa and STb), and 1 heat-labile enterotoxin (LT) gene. One hundred sixty-four (22.7%) of the 720 E. coli isolates carried genes for EAST1. Of these 164 isolates, 62 (37.8%) carried EAST1 genes only, 11 (6.7%) carried genes for at least 1 of the fimbrial adhesins, 51 (31.1%) carried genes for at least 1 of the enterotoxins, and 40 (23.8%) carried genes for at least 1 of the fimbrial adhesins and enterotoxins. Forty-six percent of strains that carried EAST1 genes carried STa genes, and 16% of strains that carried EAST1 genes carried F4. The isolation rate of enterotoxigenic E. coli strains carrying genes for EAST1 gene was 63%. The 6 major genotypes observed in this study (in decreasing order) were EAST1+, EAST1+STa+, EAST1+STa+STb+, EAST1+STa+F5+, EAST1+STa+F4+, and EAST1+STb+F4+. EAST1 is widely prevalent among diarrheagenic strains of E. coli and may represent an important virulence determinant in the pathogenesis of enteric colibacillosis of preweaned pigs.     

Inhibition of A549 Lung Cancer Cell Migration and Invasion by Ent-Caprolactin C via the Suppression of Transforming Growth Factor-β-Induced Epithelial—Mesenchymal Transition

The epithelial–mesenchymal transition (EMT) of cancer cells is a crucial process in cancer cell metastasis. An Aquimarina sp. MC085 extract was found to inhibit A549 human lung cancer cell invasion, and caprolactin C (1), a new natural product, α-amino-ε-caprolactam linked to 3-methyl butanoic acid, was purified through bioactivity-guided isolation of the extract. Furthermore, its enantiomeric compound, ent-caprolactin C (2), was synthesized. Both 1 and 2 inhibited the invasion and γ-irradiation-induced migration of A549 cells. In transforming growth factor-β (TGF-β)-treated A549 cells, 2 inhibited the phosphorylation of Smad2/3 and suppressed the EMT cell marker proteins (N-cadherin, β-catenin, and vimentin), as well as the related messenger ribonucleic acid expression (N-cadherin, matrix metalloproteinase-9, Snail, and vimentin), while compound 1 did not suppress Smad2/3 phosphorylation and the expression of EMT cell markers. Therefore, compound 2 could be a potential candidate for antimetastatic agent development, because it suppresses TGF-β-induced EMT.     

Polyozellin isolated from Polyozellus multiplex induces phase 2 enzymes in mouse hepatoma cells and differentiation in human myeloid leukaemic cell lines

Induction of cellular phase 2 detoxifying enzymes is associated with cancer preventive potential. Quinone reductase (QR) has been used as a prototype for anticarcinogenic phase 2 enzymes because of its widespread distribution in mammalian systems, large amplitude of inducer response, and ease of measurement in murine hepatoma cells. Methanol extract of Polyozellus multiplex, which shows a strong QR induction potential, was subjected to bioassay-guided fractionation, and polyozellin (PM1) appeared to be a major active component. In in vitro cultured cells (hepa1c1c7 and BPRc1 cells), polyozellin enhanced QR, glutathione S-transferase (GST) activities, and glutathione (GSH) content in a dose-dependent manner. The compound also significantly promoted differentiation of HL-60 human promyelocytic emia cells. In conclusion, polyozellin deserves further in vivo study to evaluate its potential as a cancer preventive agent.