Judul: Screening of Probiotic Bacteria for Biocuntrol of Vibriosis in Tiger Shrimp Larvae: Construction of Molecular Marker and Adherence Assay.
Abstrak: Probiotic bacteria for biocontrol of vibriosis were isolated from tiger shrimp larvae and hatchery environment. Almost all probiotic isolates could inhibit the growth of pathogenic Vibrio harveyi. SKT-b isolate from SkeIetonema was very effective in inhibiting V, harveyi and significantly reduced larval mortality in pathogen challenge assays. These prospective probiotic bacteria, at concentration 10'-10~ CFU/ml, did not show pathogenicity to shrimp larvae. SKT-b was Gram negative, short rod shape, exhibited yellow colonies an TCBS and swarming an SWC-agar media, motile, utilized glucose and sucrose but not lactose; produced extmcellular protease ancl amylase, but did not produce &itinasen Partial sequencing of 16s-rRMA gene showed that SKT-b was similar to Vib* algindyticus. To analyse mechanism of tiisease suppression by SKT-b, especially on their competition for adhesion sites, we constructed recombinant V. herveyi carrying gfp gene as a rnokufar marker. V. harvayi carrying gfp don& in a broad-host range plasmid (pWGO1) resulted in green-fluarescent colonies and cells due to the production of GFP, Growth cuwe analysis and pathogenicity assays showed that the recombinant V. Harveyi exhibited similar growth profiles as the wild type parental strain and did not show alteration in their pathogenicity. However, under nun selective long-term experiments without antibiotic pressure, pWGO? was not staMy maintained in any V. harveyi strains used in this study. Therefore we canstructed a mini Tn5 and TnIO transpuson containing gfp gene to be inserted into V. hatveyfs genamic DNA to yield stable transcanjugants. Tn5 transposition in V. harvejli strains did nut yield any transcanjugants, although we could obtain relatively trigti (10~t)r ansmjugans employing Tn10. One uf Tn 10 derived isolate of V, harvoyi G3 ((33-Tnf Ogfp) showed gfp expression and was further employed for adherence assay. Fluorescent G3-TnPOgfp cells could be obwwed inside the digestive tract of shrimp lanrae and fts population with SKT-b treatment was lower than without pmbiatic, demonstrating possible cornpetitiun for adherence sites or nutrition between V. harvsyi and SKY-b. ltrtroduction of SWb into shrimp tame through SKT-Mnriched Ademr'a resulted in higher growth rate than the mtro
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Judul: Aplikasi probiotik, prebiotik, dan sinbiotik melalui pakan pada udang vaname Litopenaeus vannamei yang diinfeksi bakteri Vibrio harveyi
Abstrak: Luminous vibriosis caused by Vibrio harveyi were commonly treated with antibiotic, but recently the use of antibiotics is restricted because it induces antibiotic-resistant bacteria and leave residue in shrimp’s body. An alternative solution that can be done to treated luminous vibriosis is by using applications of probiotic, prebiotic, and synbiotic. The aim of this research was to examine the effect of probiotic, prebiotic, and synbiotic on the survival rate and growth of pacific white shrimp against V. harveyi infection. Feed as treatment was supplemented with probiotic 1%, prebiotic 2%, and probiotik 1% + prebiotic 2% (synbiotic). Shrimps feed without supplementation of probiotic and prebiotic was used as control treatment. Shrimp test inserted into the aquarium (60x30x35) cm as much as 15 pic with a density of 40 shrimps/ 40 liters/ aquarium and an average weight of 0.4 ± 0.1 grams. After 30 days of feeding treatment, the shrimp was challenged by immersion with V. harveyi solution containing 106 CFU/ml. Survival rate of shrimp was measured before and after challenge while growth and feed convertion were observed before challenge test. Research result showed that growth (5.89%), feed convertion (1.21), and survival rate (80%) before challenge of shrimp fed diet supplemented with synbiotic were better then shrimp fed diet supplemented with probiotic and prebiotic. After challenge, survival rate (83.33%) of shrimp fed diet supplemented with synbiotic was better then prebiotic (51.67%) and positive control (31.67%).
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Judul: Perbandingan Metode Monte Carlo dan Kuasi Monte Carlo dalam Penentuan Harga Opsi Eropa
Abstrak: Opsi adalah suatu kontrak antara dua pihak di mana pemegang opsi mempunyai hak untuk membeli atau menjual suatu aset tertentu dengan harga yang telah ditentukan, pada atau sebelum waktu jatuh tempo. Opsi sebagai produk derivatif dapat mengurangi dampak risiko dalam berinvestasi dengan melakukan hedging (lindung nilai). Opsi Eropa merupakan opsi yang hanya dapat dieksekusi pada saat jatuh tempo. Karya ilmiah ini membahas penentuan harga opsi Eropa dengan menggunakan metode Monte Carlo dan Kuasi Monte Carlo dan hasilnya dibandingkan dengan harga opsi standar yang telah dihitung dengan menggunakan model Black Scholes. Berdasarkan hasil penghitungan, metode Kuasi Monte Carlo lebih cepat konvergen dengan galat relatif yang lebih kecil dibandingkan dengan metode Monte Carlo dalam penentuan harga opsi Eropa. Dengan demikian, dapat disimpulkan bahwa metode Kuasi Monte Carlo merupakan metode yang lebih baik dibandingkan metode Monte Carlo dalam penentuan harga opsi Eropa.
Keyword: opsi Eropa, Black Scholes, Monte Carlo, Kuasi Monte Carlo