Judul: Produksi dan Karakterisasi Senyawa Inhibitor alfa-Glukosidase Streptomyces sp. BWA
Abstrak: Endophitic Streptomyces sp. BWA 65 from brotowali (Tinospora crispa) produces α-glucosidase inhibitor compound that acts as antidiabetic. This study aimed to produce and characterize α-glucosidase inhibitory compound of Streptomyces sp. BWA 65 and assay its biological function as antidiabetic based on α-glucosidase inhibitory activity. Streptomyces sp. BWA 65 which was rejuvenated in Yeast Soluble Starch Agar (YSA) for 7 until 10 days, was then cultured in a liquid medium for 7 days, and produced in International Streptomyces Project-2 (ISP-2) for: 5, 10, 15, and 20 days. Then, supernatant was extracted with ethyl acetate and was assayed for α-glucosidase inhibition activity. The ethyl acetate extract of Streptomyces sp. BWA 65 was also assayed for its Inhibitor Concentration 50 (IC50) value. The characteristics of α-glucosidase inhibitor profile compounds which contained in the ethyl acetate extract was analyzed by Gas Chromatography–Mass Spectroscopy (GC-MS). The results showed that the highest α-glucosidase inhibitor activity was 98.50% when the Streptomyces sp. BWA 65 was grown on ISP-2 10 days production time. The IC50 of ethyl acetate extract of Streptomyces sp. BWA 65 was 0.047 μg ml-1. The results of GC-MS analysis were interpreted with OPCWTEST.M database showed that the ethyl acetate extract of Streptomyces sp. BWA 65 contained 7 peaks with 7 components obtained. The chemical components of ethyl acetate extract of Streptomyces sp. BWA 65, were: 9-octadecenoic acid, (E)-, oleic acid, dan 6-octadecenoic acid, (Z)-.
Keyword: Bogor Agricultural University (IPB), Streptomyces sp. BWA 65, GC-MS, IC50, α-glukosidase inhibitor

Judul: Aktivitas Inhibitor Alpha Glukosidase Streptomyces sp. BWA 65 pada beberapa Media, pH, dan Suhu
Abstrak: Streptomyces sp. BWA 65 is a genus of actinomycetes from brotowali (Tinospora crispa), which produces α-glucosidase inhibitor as antidiabetic. Production of this compound is influenced by external factors such as media, pH, and temperature. The α-glucosidase inhibitor activity was assessed at various media, pH, and temperature. Streptomyces sp. BWA 65 grew and sporulated well on YSA medium, indicated by the formation of white colonies after incubation for 7-10 days. ISP-2 medium was the best growth medium compared with YS and ISP-4 media. In this ISP-2 medium, Streptomyces sp. BWA 65 produced optimum inhibition of it’s supernatant and it’s ethyl acetate extract after 10 days of production time. This optimum growth condition was used for the production of α-glucosidase inhibitor compound using a fermentor at control condition, e.g. 27- 29 °C, pH 7, and oxygen pressure at 3-5 mmHg. The α-glucosidase inhibitor compound produced was assayed at various pH and temperature. The higest percentage of inhibitor activity of supernatant and ethyl acetate extract was found at pH 7, 27 °C for 24 h incubation. At this condition, the highest percentage of inhibition of the supernatant was 90.2 %, while for ethyl acetate extract was 91.8 %. As a comparison, acarbose at 1000 ppm concentration gave 98,6 % inhibition activity.
Keyword: Bogor Agricultural University (IPB), temperature, Streptomyces sp. BWA 65, pH, medium, α-glukosidase inhibitor activity

Judul: Peramalan enso dan pemodelan hubungan enso dengan curah hujan monsoon
Abstrak: Curah hujan merupakan salah satu paramclcr iklim yang sangal bcrpcngaruh dalam bidang pcrlmlim1. Scdangkan ENSO atau El-Nino SouLl1rc11 Oscillation mcrupakan salah satu faktor global yang dapat mcmpengaruhi kcjadian dan pola curah hujan di Indonesia, khususnya wilayah dcngan tipc curah hujan monsoon. Peramalan pola dan nilai ENSO di masa yang akan datang pcrlu untuk dikctahui, schingga variabilitas kejadim1 curah hujan dapat ditindaklanjuti. Dalam pcnclitim1 ini dipclajari pcngaruh ENSO tcrhadap dacrah ·yang mcmiliki tipc cu rah hujan monsoon dcngan dua ta ha pan analisis. (I) Pcramalan ENSO dan (2) Pcmodclan ENSO dcngan Curah Hujan Monsoon. Pcrmnalan ENSO dcngan mcnggunakan mctodc Gcostatistika dcngan pcndckatan intcrpolasi dan ckstrapolasi analisis kcccndcrugan pcrmukaan, mcnghasilkan nilai pcramalan yang cukup baik bila dibandingkan dcngan pcndckatan mctodc Winters dcngan nilai R2 antara 14.57%1, 79.81%, dan ragam pcrmnalan 1.772146 - 5.295013. Karaktcristik model yang dihasilkan mcnunjukkan pola nilai tckanan dan suhu yang ccndcrung mcningkat dari tahun kc tahun bcrikutnya, kccuali tckanan Tahiti yang ccndcrung turun. Hubungan ENSO dcngm1 cuntl1 hujan monsoon untuk kc-crnun stasiun cukup baik bila didckati dengan rcgresi metode !mad.rat terkccil (OLS dan WLS) dibandingkan regrcsi komponcn utama (Principal Component Regression) . Model yang dihasilkan mcmiliki kcmampuan dcm validasi yang cukup b::iik. Nilai-nilai ramalan kc-cnam model yang ada mampu mcngikuli pola dala aktual untuk tmum I 998. Schingga model ini dapat digm1akan scbagai aJtcrnatif lain dalam pcramaJan curah hujan w1tuk kc-cnam stasiun di masa yang berikut..nya.
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