Judul: Toxicity and Immunogenicity of Non-hemolytic Streptococcus agalactiae Extracellular Products to Tilapia Oreochromis niloticus.
Abstrak: Toxicity and immunogenicity of extracellular products (ECP) of non-hemolytic Streptococcus agalactiae were studied in the tilapia Oreochromis niloticus. The aim of this research was to analyse the toxicity and immunogenicity of ECP of non-hemolytic S. agalactiae and to evaluate ECP as a material vaccine for prevention of S. agalactiae. Toxicity to tilapia was detected in the ECP. There was a chronic mortality pattern which was shown after post ECP injection. By intraperitoneal injection into young tilapia (± 20 g), the median lethal dose were calculated at 633,9 μg/kg bodyweight for isolate 3 and 685,4 μg/kg bodyweight for isolate 5. Cytopathic effects of ECP to tilapia’s lymphocytes were observed during 0, 30, 60 and 180 minutes. A mixture of ECP caused nuclear granulation and cytoplasmic streaming after 60 minutes. Using immunodiffusion analysis, precipitate line was demonstrated against tilapia anti-ECP sera, and there was bio-specific type anti sera against for each isolate. The ECP vaccine effective to protect tilapia from S. agalactiae was injected intraperitoneally (IP) at 2 x 105 CFU/ml. Tilapia vaccinated with ECP from isolat 3 which protein 283 μg/kg bodyweight had a RPS value 60%. Tilapia vaccinated with ECP from isolat 5 which protein 408 μg/kg had a RPS value 68%.
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Judul: Efficacy of Streptococcus agalactiae Oral Vaccine with Different Doses in Tilapia (Oreochromis niloticus)
Abstrak: Ikan nila (Oreochromis niloticus) merupakan salah satu komoditas air tawar unggulan yang mengalami peningkatan produksi, namun masih belum memenuhi target produksi setiap tahun. Hal tersebut disebabkan oleh penyakit streptococcosis di pembesaran ikan nila yang penyebabnya adalah Streptococcus agalactiae. Vaksinasi adalah salah satu upaya penanggulangan penyakit ikan yang dapat diaplikasikan secara oral melalui pakan. Penelitian ini bertujuan menguji efikasi vaksin oral Streptococcus agalactiae pada ikan nila dengan penerapan dosis yang berbeda serta menganalisis sistem imun spesifik dan nonspesifik ikan nila yang divaksinasi. Ikan nila yang digunakan memiliki bobot awal 10,72 ± 0,95 g dan panjang 8,72 ± 0,44 cm. Pemeliharaan berlangsung selama 30 hari dan uji tantang selama 14 hari dengan bakteri S. agalactiae. Perlakuan yang diterapkan meliputi kontrol negatif (K-), kontrol positif (K+), 105 CFU/g pakan (A), 107 CFU/g pakan (B) dan 109 CFU/g pakan (C). Setelah vaksinasi, ikan dipelihara selama 30 hari dan diberi pakan komersial secara at satiation. Hasil penelitian menunjukan aplikasi vaksin oral mampu meningkatkan kelangsungan hidup relatif, serta respons imun berbeda nyata (P<0,05) dibandingkan kontrol. Vaksinasi dengan dosis 107 CFU/g pakan sudah dapat memberi proteksi terhadap serangan S. agalactiae dan meningkatkan kekebalan spesifik yang terlihat pada peningkatan level antibodi., Tilapia (Oreochromis niloticus) is one of the leading freshwater commodities which has increased production, but it still does not meet the annual production target. This is caused by streptococcosis disease which is the cause is Streptococcus agalactiae in the grow-out of tilapia. Vaccination is one of the efforts to control fish diseases that can be applied orally through the feed. This study aimed to test the efficacy of Streptococcus agalactiae oral vaccine in tilapia with different doses applied and analyze the specific and non-specific immune systems of vaccinated tilapia. The tilapia used had an initial weight of 10,72 ± 0,95 g and a length of 8,72 ± 0,44 cm. Maintenance lasted for 30 days and trials for 14 days with S. agalactiae. The treatments applied included a negative control (K-), positive control (K+), 105 CFU/g feed (A), 107 CFU/g feed (B), and 109 CFU/g feed (C). After vaccination, fish were reared for 30 days and fed commercial feed on at satiation. The results showed that oral vaccine application was able to increase relative survival and immune response and was significantly different (P<0,05) compared to controls. Vaccination with a dose of 107 CFU/g of feed was able to provide protection against S. agalactiae attacks and increase specific immunity as seen in the increase in antibody levels.
Keyword: dose, tilapia, protection, Streptococcus agalactiae, oral vaccine

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf