A comparison of the pathogenicity of avian and swine H5N1 influenza viruses in Indonesia

Highly pathogenic avian influenza H5N1 viruses are circulating in many countries. We recently discovered that these viruses have been transmitted to pigs on multiple occasions in Indonesia. To investigate whether avian H5N1 influenza viruses adapted to mammals through their introduction into pigs, we examined the growth of avian and swine isolates in cell culture and compared their pathogenicity in mice. We found that swine isolates were less virulent to mice than avian isolates, suggesting that the viruses became attenuated during their replication in pigs. Continuous surveillance of H5N1 viruses among pigs is clearly warranted.     

The green synthesis of a palm empty fruit bunch-derived sulfonated carbon acid catalyst and its performance for cassava peel starch hydrolysis

A sulfonated carbon acid catalyst (C–SO₃H) was successfully generated from palm empty fruit bunch (PEFB) carbon via hydrothermal sulfonation via the addition of hydroxyethylsulfonic acid and citric acid. The C–SO₃H catalyst was identified as containing 1.75 mmol g⁻¹ of acid and 40.2% sulphur. The surface morphology of C–SO₃H shows pores on its surface and the crystalline index (CrI) of PEFB was decreased to 63.8% due to the change structure as it became carbon. The surface area of the carbon was increased significantly from 11.5 to 239.65 m² g⁻¹ after sulfonation via hydrothermal treatment. The identification of –SO₃H, COOH and –OH functional groups was achieved using Fourier-transform infrared spectroscopy. The optimal catalytic activity of C–SO₃H was achieved via hydrolysis reaction with a yield of 60.4% of total reducing sugar (TRS) using concentrations of 5% (w/v) of both C–SO₃H and cassava peel starch at 100 °C for 1 h. The stability of C–SO₃H shows good performance over five repeated uses, making it a good potential candidate as a green and sulfonated solid acid catalyst for use in a wide range of applications.

A sulfonated carbon acid catalyst (C–SO₃H) was successfully generated from palm empty fruit bunch (PEFB) carbon via hydrothermal sulfonation via the addition of hydroxyethylsulfonic acid and citric acid.     

Induction of TNF-α in human macrophages by avian and human influenza viruses

The highly pathogenic avian influenza virus H5N1 is known to induce high level of tumor necrosis factor α (TNF-α) from primary macrophages. However, it is still unclear whether current H5N1 strains also induce high TNF-α production, as most of the data were derived from extinct clade 0 H5N1 strain. Here, we show that current clade 1 and 2 H5N1 strains induce variable levels of TNF-α that are not necessarily higher than those induced by seasonal influenza viruses. The result suggests that hyper-induction of TNF-α in human macrophages is not always associated with a highly pathogenic phenotype. We further tested the contribution of the NS gene segment from H5N1 isolates to TNF-α induction by using reverse genetics. While NS conferred some variation in TNF-α induction when incorporated into an H1N1 virus genetic background, it did not affect TNF-α induction in an H5N1 virus genetic background, suggesting that other viral genes are involved.     

Influenza A (H5N1) Viruses from Pigs, Indonesia

Pigs have long been considered potential intermediate hosts in which avian influenza viruses can adapt to humans. To determine whether this potential exists for pigs in Indonesia, we conducted surveillance during 2005–2009. We found that 52 pigs in 4 provinces were infected during 2005–2007 but not 2008–2009. Phylogenetic analysis showed that the viruses had been introduced into the pig population in Indonesia on at least 3 occasions. One isolate had acquired the ability to recognize a human-type receptor. No infected pig had influenza-like symptoms, indicating that influenza A (H5N1) viruses can replicate undetected for prolonged periods, facilitating avian virus adaptation to mammalian hosts. Our data suggest that pigs are at risk for infection during outbreaks of influenza virus A (H5N1) and can serve as intermediate hosts in which this avian virus can adapt to mammals.     

Anti-babesial and anti-plasmodial compounds from Phyllanthus niruri

Bioassay-guided fractionation of boiled aqueous extracts from the whole plant of Phyllanthus niruri led to the isolation of 1-O-galloyl-6-O-luteoyl-alpha-d-glucose (1), with IC(50) values of 4.7 microg/mL against Babesia gibsoni and 1.4 microg/mL against Plasmodium falciparum in vitro. The known compounds beta-glucogallin (2), quercetin 3-O-beta-d-glucopyranosyl-(2-->1)-O-beta-d-xylopyranoside (3), beta-sitosterol, and gallic acid were also isolated. Structures of these compounds were elucidated on the basis of their chemical and spectroscopic data.     

Anti-babesial compounds from Curcuma zedoaria

Anti-babesial activity was confirmed in an extract of the bark of Curcuma zedoaria. The active ingredients were isolated, and their chemical structures were determined to be zedoalactones A, B, and C based on spectral data. Zedoalactone C is a hitherto unreported compound. The IC50 vales of these active compounds against Babesia gibsoni were compared with a standard drug, diminazene aceturate. The IC50 value of diminazene aceturate was 0.6 microg/mL, while those of zedoalactones A, B, and C were 16.5, 1.6 and 4.2 microg/mL, respectively.     

Genetic characterization of H5N1 influenza viruses isolated from chickens in Indonesia in 2010

Since 2003, highly pathogenic H5N1 avian influenza viruses have caused outbreaks among poultry in Indonesia every year, producing the highest number of human victims worldwide. However, little is known about the H5N1 influenza viruses that have been circulating there in recent years. We therefore conducted surveillance studies and isolated eight H5N1 viruses from chickens. Phylogenic analysis of their hemagglutinin and neuraminidase genes revealed that all eight viruses belonged to clade 2.1.3. However, on the basis of nucleotide differences, these viruses could be divided into two groups. Other viruses genetically closely related to these two groups of viruses were all Indonesian isolates, suggesting that these new isolates have been evolving within Indonesia. Among these viruses, two distinct viruses circulated in the Kalimantan islands during the same season in 2010. Our data reveal the continued evolution of H5N1 viruses in Indonesia.     

Cross-clade protective immunity of H5N1 influenza vaccines in a mouse model

H5N1 highly pathogenic avian influenza viruses evolved into several clades, leading to appreciably distinct antigenicities of their hemagglutinins. As such, candidate H5N1 pre-pandemic vaccines for human use should be sought. Here, to evaluate fundamental immunogenic variations between H5N1 vaccines, we prepared four inactivated H5N1 test vaccines from different phylogenetic clades (clade 1, 2.1, 2.2, and 2.3.4) in accordance with the WHO recommendation, and tested their cross-clade immunity in a mouse model by vaccination followed by challenge with heterologous virulent viruses. All H5N1 vaccines tested provided full or partial cross-clade protective immunity, except one clade 2.2-based vaccine, which did not protect mice from clade 2.3.4 virus challenge. Among the test vaccines, a clade 2.1-based vaccine possessed the broadest-spectrum cross-immunity. These results suggest that currently stockpiled pre-pandemic vaccines, especially clade 2.1-based vaccines, will likely be useful as backup vaccines in a pandemic situation, even one involving antigenic-drifted viruses.     

Correlation between Mutations in the Interferon Sensitivity-Determining Region of NS5A Protein and Viral Load of Hepatitis C Virus Subtypes 1b, 1c, and 2a

In the present study, we analyzed the possible relationship between interferon (IFN) sensitivity-determining region (ISDR) sequence variation of various hepatitis C virus (HCV) subtypes and serum HCV titers in Indonesian patients without IFN treatment. The viremia titers (mean +/- standard deviation) of HCV subtype 1b (HCV-1b) isolates with low (three or fewer) and high (four or more) numbers of ISDR mutations were 5.4 +/- 0.6 and 4.2 +/- 0.9 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Similarly, the viremia titers of HCV-1c isolates with low and high numbers of ISDR mutations were 5.3 +/- 0.6 and <3.0 +/- 0.0 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Also, the virus titers of HCV-2a isolates with low and high numbers of ISDR mutations were 4.3 +/- 0.7 and 3.5 +/- 0.4 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Thus, our results demonstrated that virus load in Indonesian patients infected with HCV-1b, HCV-1c, or HCV-2a correlated inversely with the number of mutations in the ISDR sequence, implying the possibility that the ISDR sequence plays an important role in determining the levels of HCV viremia.