Judul: Pencirian Gen Serupa Subtilisin Pada Sejumlah Isolat Lokal Bakteri Proteolitik
Abstrak: Pencarian jenis mikroba asal Indonesia sebagai sumber protease serin serupa sub- tilisin, dilakukan dengan melacak keberadaan gen penyandi enzim serupa subtilisin melalui hibridisasi Southern dan pengujian aktivitas protease dengan penghambat spesifik serin, fenilmetilsulfonil fluorida (PMSF). Sebagai pelacak adalah fragmen DNA penyandi gen subtilisin BPN yang terdapat dalam plasmid pPT30, pada situs EcoRI, berukuran 3.0 kilo pasang basa (Kb). Konsentrasi PMSF yang digunakan dalam pengujian penghambatan aktivitas protease adalah 1 mM dan 5 mM. Pada penelitian ini digunakan 25 isolat bakteri, yang terdiri dari 21 isolat Bacillus sp. dan 4 isolat Vibrio harveyi. Semua isolat bakteri diisolasi dari berbagai tempat di Indonesia. Isolat-isolat tersebut mengeluarkan enzim protease yang ditandai dengan terbentuknya areal bening (halo) di sekitar koloni pada media skim milk agar (SMA) dan aktivitas optimum protease pada pH 8.0. Protease dari keempat isolat Vibrio harveyi tidak menunjukkan penghambatan de- ngan penambahan 1 mM PMSF dan 5 mM PMSF. Penambahan 1 mM PMSF mengakibatkan penghambatan aktivitas protease B. licheniformis MD15 sebesar 49.89% dan protease B. pumilus Y1 mengalami penghambatan sebesar 43.96% (B. subtilis kontrol mengalami penghambatan aktivitas sebesar 40%). Penambahan 5 mM PMSF mengakibatkan peng- hambatan aktivitas lebih dari 40% untuk protease dari B. pumilus (BK1, M, MD13p, $1, Y1 dan Y3), B. brevis (BK2, MD21.2), B. stearothermophilus JD, B. licheniformis (MD13k, MD15, R1), B. subtilis N dan B. sphaericus S3. Protease B. pumilus Y1 mengalami penghambatan aktivitas terbesar dibandingkan dengan protease yang dihasilkan oleh isolat lainnya dengan penambahan 5 mM PMSF. Aktivitas tersisa dari protease B. pumilus Yl dengan penambahan 5 mM PMSF sebesar 27.2% (B. subtilis kontrol memberikan aktivitas tersisa sebesar 4.10%)….dst
Keyword: Protease Serin, Penghambatan Protease, Plasmid, Hibridisasi Sauthern

Judul: engklonan Gen Protease Serupa Subtilisin dari Bacillus pumilus YI ke dalam Escherichia coli DH5a,
Abstrak: Studi pelacakan dengan menggunakan gen kimotripsin dari fragmen BamHl plasmid pJB, diperoleh hasil bahwa tidak satupun Bacillus sp. yang diisolasi dari Indonesia, termasuk Bacillus pumilus YI, memiliki gen penyandi serupa kimotripsin. Ristiarini (1996) telah melokalisir gen penyandi enzim protease serupa subtilisin pada Bacillus pumilus YI dengan menggunakan metode hibridisasi southern. Gen serupa subtilisin tersebut terdapat pada fragmen DNA genom hasil digesti EcoRI yang berukuran 3 kb. Pada penelitian ini dilakukan pengklonan gen penyandi enzim serupa subtilisin ke dalam Escherichia coli DH5a dengan menggunakan vektor pUC 19. Dari hasil pengklonan diperoleh beberapa koloni putih., yang setelah direplika pada media yang mengandung skim (skim milk agar ) diperoleh empat koloni putih yang menghasilkan halo yang tipis setelah diinkubasi selama 4 hari pada suhu 37°C. Hasil verifikasi plasmid diperoleh adanya beberapa DNA sisipan (insert) dengan ukuran yang berbeda, yaitu 0.3 kb, 0,9 kb, 1,5 kb, 2.4 kb, 2,6 kb, 2, 7 kb, dan 3,0 kb. Plasmid-plasmid rekombinan ini dilµbridisasi dengan menggunakan pelacak gen subtilisin dari fragmen .&oRI plasmid pPT30. Dua dari plasmid rekombinan ini menghasilkan signal positif dengan ukuran 2.4 kb, 2.6 kb, dan dua plasmid rekombinan lainnya berukuran hampir sama yaitu 3 kb. Dengan demikian gen penyandi enzim protease serupa subtilisin dari Bacillus pumi/us YI telah terklon dan plasmid rekombinannya berturut-turut disebut : pBNI, pBN2, pBN3, dan pBN4. Selama pertumbuhan pada Luria broth pada suhu 37°C, E. coli rekombinan rnenghasilkan aktivitas protease tertinggi yaitu 0.2307 U/ml setelah 15 jam fermentasi, dan secara umum protease yang dihasilkan bersifat sensitif terhadap PMSF.
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Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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