Judul: Isolasi Senyawa Antibiotik dari Aktinomisetes Laut Selat Lembeh di Sulawesi Utara
Abstrak: Aktinomisetes merupakan bakteri Gram positif yangtersebar luas di alam, termasuk di lingkungan perairan. Aktinomisetes laut berhasil diisolasi dari selat Lembeh di Sulawesi Utara. Penelitian ini bertujuan mengisolasi senyawa aktif sepuluh isolat aktinomisetes laut dari selat Lembeh Sulawesi Utara. Antibiotik didapatkan dengan ekstraksi dan diuji aktivitas antibakteri menggunakan metode microplate resazurin assay (MRA). Senyawa aktif dari ekstrak dikarakterisasi menggunakan high performance liquid chromatography (HPLC) dengan standar antibiotik penisilin, ampisilin, tetrasiklin, fradiomisin, gentamisin, eritromisin, streptomisin, kloramfenikol, dan klortetrasiklin. Dari sepuluh isolat, semua isolat aktinomisetes mampu menghasilkan antibiotik ditunjukkan dengan warna biru bahwa garam resazurin tidak mengalami reduksi menjadi warna merah muda dalam bentuk resorufin, karena tidak adanya bakteri yang hidup. Hasil uji aktivitas antibakteri terdapat tiga ekstrak yang paling unggul dalam menghambat bakteri uji yaitu BLH 5-22, BLH 3-12, dan BLH 1-22. Hasil HPLC senyawa aktif dari ekstrak memperlihatkan adanya antibiotik eritromisin pada kromatogram ekstrak BLH 5-22, BLH 3-12, dan BLH 1-22.
Keyword: Aktinomisetes, antibiotik, HPLC, metode MRA

Judul: Identifikasi Aktinomisetes Laut dari Selat Lembeh di Sulawesi Utara dengan Gen 16S rRNA
Abstrak: Aktinomisetes merupakan bakteri Gram positif yang tersebar luas di alam, termasuk di lingkungan perairan. Beragam karakteristik laut di Indonesia dapat mengindikasikan biodiversitas aktinomisetes laut yang besar. Aktinomisetes laut berhasil diisolasi dari selat Lembeh di Sulawesi Utara. Penelitian ini bertujuan mengidentifikasi 20 isolat aktinomisetes laut dari selat Lembeh Sulawesi Utara dengan gen 16S rRNA. Identifikasi aktinomisetes terdiri atas beberapa tahapan, yaitu isolasi DNA genom, kuantisasi DNA genom secara spektrofotometri, amplifikasi gen penyandi 16S rRNA dengan primer universal (9F dan 1541R), elektroforesis agarosa, pengurutan basa nitrogen (sekuensing), dan analisis bioinformatika. Gen penyandi 16S rRNA dari seluruh isolat berhasil diamplifikasi dan memiliki ukuran ± 1500 bp. Hasil identifikasi 20 isolat aktinomisetes berdasarkan homologi sekuen gen 16S rRNA dan profil filogenetik diperoleh 8 isolat tergolong genus Micromonospora, 7 isolat tergolong genus Streptomyces, dan 5 isolat menjadi kandidat spesies baru yang memerlukan analisis lebih lanjut.
Keyword: Aktinomisetes, gen penyandi 16S rRNA, sekuensing, selat Lembeh

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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