Judul: Kajian bioprospeksi spons laut asal taman nasional kepulauan Wakatobi dan implikasi pengelolaannya
Abstrak: Most of eastern region of Indonesian waters are located in biodiversity center of coral triangle ecoregion and Wakatobi Archipelago Marine Park is one of them. Marine sponge is one of prominent benthic marine organism in coral reef. It is one of the prolific sources of pharmacological bioactive substances that are useful for drug development. About 30% of potentially natural products for drug lead had been isolated from marine sponges. Their bioactive substance has varied potential such as anticancer, antivirus, antimicrobe, anti-inflamation, and antimalaria. Based on preliminary cytotoxic assay on sponge crude extracts in 2008, marine sponge extracts (code W-19-08 and W-36-08) were among marine sponges collected from Wakatobi Archipelago National Park that had the potential of its cytotoxic activity. The purpose of this research were to examine sponge crude extract Lethal Concentration (LC50) and to describe human breast cancer cell line T47D morphology after treating with crude extract. The in vitro cytotoxicity assay was conducted using MTT method. In vitro cytotoxicity assay showed that marine sponge extracts W-19-08 and W-36-08 bioactivity were considered to medium with the LC50 value of 156.14 and 97.04 ppm, respectively. The cell line T47D morphology showed that these extracts were considered of having cytostatic properties.
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Judul: Toksisitas Ekstrak Senyawa Bioaktif dari Bakteri yang Berasosiasi dengan Spons dan Analisis DNA yang Berperan dalam Biosintesisnya
Abstrak: Sponges are organisms that produced many bioactive compounds and live symbiotically with many microorganisms. Symbiont microorganisms act as producers of bioactive compounds for sponge self-defense. This study aims to test the toxicity of the ethyl acetate extract sponge-associated bacteria against Artemia salina larvae and diversity analysis of DNA that play a role in the synthesis of bioactive compounds. BSLT was used as toxicity assay method and obtained LC50 values ranged from 117.1 μg/mL to 620 μg/mL. Fractionation of the ethyl acetate extract for isolates SAB E-35, SAB E-38 and SAB E-40 using preparative thin layer chromatography technique (PTLC) yielded fraction with the best LC50 value 116.7 μg/mL. Fraction 38-E of isolate SAB E-38 showed increase in LC50 value from its etyl acetat extract 138.6 μg/mL to 116.7 μg/mL. Isolates SAB E-35, SAB E-38, and SAB E-40 has gene that encoded the KS domain of PKS and A domain of NRPS with homology percentage from 47% to 100%. SAB E-40 has low homology and expected as potential producer of new bioactive compounds
Keyword: toxicity, sponge-associated bacteria, PKS, NRPS

Judul: Analysis of M/G/1 Queue Model with Two Phases of Service and Bernoulli Feedback System
Abstrak: Model antrean M/G/1 dengan sistem feedback Bernoulli adalah model antrean dengan proses kedatangan mengikuti proses Poisson. Pada karya ilmiah ini dibahas sistem antrean M/G/1 dengan dua fase layanan. Setelah layanan pertama selesai, pelanggan dapat memilih untuk meninggalkan sistem dengan peluang ... dst, The M/G/1 queueing model with the Bernoulli feedback system is a queueing model with the arrival process following the Poisson process. In this manuscript M/G/1 queueing system with two phases of service is discussed. After the first service is completed, the customer can choose to leave the system with probability ... dst
Keyword: queue, Bernoulli, probability generating function, expected value