Judul: The Potential of NanB Sialidase from Pasteurella multocida Bacteria in Inhibiting Replication of Avian Influenza Virus H9N2 In Ovo
Abstrak: Virus avian influenza (VAI) subtipe H9N2 mengancam industri unggas dan kesehatan masyarakat karena berpotensi zoonotik. Antiviral berbasis sialidase dikembangkan sebagai upaya pencegahan dan pengobatan infeksi virus seperti VAI yang memerlukan sialic acid pada point of entry ke dalam sel. Penelitian ini bertujuan menganalisis potensi NanB sialidase asal Pasteurella multocida dalam menghambat infeksi virus avian influenza subtype H9N2 (VAI-H9N2) secara in ovo. Strain A/Layer/Indonesia/WestJava-04/17 dan NanB sialidase yang digunakan dalam penelitian ini berasal dari PT. Medika Satwa Laboratoris. Virus diidentifikasi ulang dengan quantitative real-time polymerase chain reaction (qRT-PCR) dan ditentukan titer virusnya embryo infectious dose (EID)50. Toksisitas NanB sialidase diuji terhadap beberapa dosis secara in ovo. Uji tantang virus dilakukan untuk menentukan aktivitas antiviral NanB Sialidase, menggunakan telur ayam berembrio (TAB) dengan tiga perlakuan yaitu: pemberian sebelum, saat, dan setelah ditantang. Hasil penelitian menunjukkan bahwa titer virus adalah 108,83 EID50/ml. Dosis efektif dan tidak toksis NanB sialidase dalam menghambat infeksi virus pada TAB yaitu dosis 0,129 U/ml. Kelompok pemberian sialidase setelah tantang menunjukkan aktivitas antiviral NanB sialidase yang paling efektif. Studi ini menunjukkan potensi NanB sialidase asal Pasteurella multocida sebagai antiviral VAI dengan pendekatan terapeutik., Avian influenza virus (AIV) subtype H9N2 threatens the poultry industry and public health due to its zoonotic potential. Antivirals based on sialidase have been developed as a prevention and treatment measure for viral infections such as AIV, which require sialic acid at the point of entry into cells. This study aims to analyze NanB sialidase of Pasteurella multocida ability to inhibit avian influenza virus subtype H9N2 (AIV-H9N2) infection in ovo. The strain A/Layer/Indonesia/WestJava-04/17 and NanB sialidase used in this study were belong to PT. Medika Satwa Laboratoris. The virus was re-identified using quantitative real-time polymerase chain reaction (qRT-PCR) and embryo infectious dose (EID)50 was determined. NanB sialidase toxicity was tested at several doses in ovo. Virus challenge test was conducted to determine antiviral activity of NanB sialidase, using embryonated chicken eggs (ECE), with three treatments: before, during, and after challenge. The results showed that the virus titer is 108,83 EID50/ml. Effective and non-toxic dose of NanB sialidase to virus infection in ECE was 0,129 U/ml. The group given sialidase after challenge showed the most effective antiviral activity of NanB sialidase. This study demonstrates potential of NanB sialidase from Pasteurella multocida as an antiviral for AIV with a therapeutic approach.
Keyword: Antiviral, In ovo, NanB sialidase, Pasteurella multocida, VAI-H9N2

Judul: Characteristics of Avian Influenza H9N2 Hemagglutinin Gene After Inhibition of Infection by Sialidase from Pasteurella multocida In Ovo
Abstrak: Pencegahan dan pengobatan virus pada saluran pernapasan telah banyak digunakan, salah satuya adalah sialidase. Sialidase asal bakteri Pasteurella multocida telah terbukti efektif menekan infeksi virus H9N2. Namun, perlu dilakukan penelitian lebih lanjut terkait efek yang akan terjadi pada virus apabila terus diberikan sialidase. Pada proses interaksi virus dan inang, virus dapat melarikan diri dengan merubah susunan asam amino pada gen hemaglutinin. Protein HA1 merupakan situs utama yang mengalami antigenic drift karena besarnya jumlah epitop. Penelitian ini bertujuan menganalisis karakteristik molekuler gen hemaglutinin avian influenza H9N2 pasca penghambatan oleh sialidase asal bakteri Pasteurella multocida. Penelitian ini menggunakan isolat dengan nama A/Layer/Indonesia/WestJava-04/2017. Konfirmasi virus dilakukan menggunakan reverse transcription polymerase chain reaction. Setelah itu, dilakukan pasase sebanyak lima kali pada kelompok placebo dan kelompok sialidase. Gen hemaglutinin disekuensing menggunakan metode sanger dan dianalisis pada receptor binding pocket, homologi, dan filogenetik. Hasil penelitian ini menunjukan seluruh kelompok tidak mengalami perubahan pada gen HA setelah lima pasase. Perbandingan homologi menunjukan 100% serupa dengan virus awal. Pohon filogenik menunjukan ada keterkaitan pada isolat A/muscovy_duck /Vietnam/LBM719/2014 dan A/chicken/Henan/LY-36/2013., The prevention and treatment of viruses in the respiratory tract have been widely used, including sialidase. Sialidase from the bacterium Pasteurella multocida has been shown to be effective in suppressing H9N2 virus infection. However, further research is needed regarding the effect that will occur on the virus if sialidase is continued. During the interaction between the virus and the host, the virus can escape by changing the amino acid sequence in the hemagglutinin gene. The HA1 protein is the main site that experiences antigenic drift due to a large number of epitopes. This study aims to analyze the molecular characteristics of the avian influenza H9N2 hemagglutinin gene after inhibition by sialidase from the bacterium Pasteurella multocida. This study used isolates with the name A/Layer/Indonesia/WestJava-04/2017. Virus confirmation was performed using reverse transcription polymerase chain reaction. After that, five passages were performed in the placebo and sialidase groups. The hemagglutinin gene was sequenced using the Sanger method and analyzed for receptor binding pocket, homology, and phylogenetics. The results of this study showed that all groups did not experience changes in the hemagglutinin gene after five passages. Homology comparisons show 100% similarity to the original virus. The phylogenic tree shows that there is a relationship between A/muscovy_duck/Vietnam/LBM719/2014 and A/chicken/Henan/LY-36/2013 isolates.
Keyword: H9N2, mutation, pasteurella multocida, sialidase

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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