Judul: Improvement of pigment and lovastatin angkak production by Monascus purpureus strains co-cultured with indigenous amylolitic yeast
Abstrak: Angkak is a natural food colorant while lovastatin have been reported recently as bioactive component due to its capacity lowering cholesterol biosynthesis level in rat and human. Pigment and lovastatin angkak are secondary metabolites of Monascus purpureus. The objectives of this study were to increase pigment and lovastatin productions by co-cultured with Endomycopsis burtonii. Six strains of M. purpureus (107cfu/ml) were co-cultured with various concentrations of E. burtonii (103-105) cfu/ml at three different feeding times (day 2, 4, and 6). Feeding time and concentration of E. burtonii affected the productions of both pigment and lovastatin. The highest productions of red pigment and lovastatin were achieved by the same strain (M. purpureus TOS) at 104 cfu/ml of E. burtonii added at day 6. Expression of the genes that responsible for lovastatin production were analyzed by PCR and RT-PCR method. The phenotypic character of M. purpureus TOS with high lovastatin production was conformed by the high intensity of its gene expression. The stabilities of pigment and lovastatin were studied at various temperatures (70- 121)˚C and contact times (15, 30, and 45 minutes) and various pH (3,0; 5,0 ; and 7,0) with contact times (2, 4, 6, 8 h). The results showed that both red pigment produced by mono- and co-culture were stable at 70-121˚C for 15-45 minutes and at pH 7,0 with contact times for 4-8 h. However at lower pH 3,0 and 5,0 with contact times for 2-8 h caused degradation of red pigment.produced by either monoculture or co-cultured. Heating angkak at 70-121˚C for 15-30 and at pH 7,0 for 2-8 h did not affect the lovastatin concentration, while heating at 121˚C with longer contact time (45 minutes) and at pH 3,0-5,0 for 2-8 h caused the degradation of lovastatin (by coculture). The concentration of lovastatin (by mono-culture) did not affect by heating 70-121˚C for 15-45 minutes and at pH 3,0-7,0 with contact times for 4-8 h.
Keyword: Monoculture, Co- cultured, Khamir Indigenus

Judul: Uji hayati isolat Monascus purpureus JmbA sebagai penurun kolesterol darah tikus Sprague dawley
Abstrak: Lovastatin dihasilkan oleh M.purpureus dan merupakan inhibitor kompetitif 3- hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG KoA reduktase). Enzim ini mengatur biosintesis kolesterol, dan bila kerjanya dihambat dapat menurunkan kolesterol dalam darah. Penelitian ini menguji hayati isolat M.purpureus JmbA yang mengandung lovastatin terhadap kadar kolesterol darah tikus putih Sprague Dawley yang diberi pakan kolesterol dan PTU 0,01%. Tikus diukur kadar kolesterol total, trigliserida, kolesterol HDL dan kolesterol LDL tiap 7 hari selama 21 hari. Dalam 21 hari isolat M.purpureus JmbA mampu menekan kenaikan kadar kolesterol total darah sebesar 49.28% dan kolesterol LDL sebesar 186.9% relatif terhadap kelompok kontrol positif. Pemberian M.purpureus juga mampu meningkatkan kadar kolesterol HDL pada hari ke-21 yaitu sebesar 26.34% dibandingkan hari ke-0. Hasil percobaan ini menunjukkan bahwa M.purpureus JmbA mampu menurunkan kadar kolesterol darah dan dapat digunakan sebagai alternatif obat penurun kolesterol./ Lovastatin produced by M.purpureus is an inhibitor of 3-hydroxy-3-methyl- glutaryl coenzyme A reductase. This enzyme controls biosynthesis of cholesterol, so that lovastatin can reduced blood cholesterol. Bioassay was carried out using Sprague Dawley rats, hypercholesterolemic fed and supplemented with 0,01% PTU. Every 7 days for 21 days experiment, blood was drawn and total cholesterol, trygliserides, HDL-cholesterol and LDL-cholesterol were measured. In 21 days, M.purpureus JmbA was able to reduces total cholesterol 49.28% and LDL-cholesterol 186.90% relatively to the control. It also increased HDL-cholesterol 26,34% measured on day-21st. The result showed that M.purpureus JmbA was able to reduces blood cholesterol and can be used as an alternative for cholesterol lowering medicine.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf