Judul: Isolasi Fragmen Gen Penyandi Endoxilanase Streptomyces costaricanus 45I-3 melalui pendekatan PCR
Abstrak: Xilan merupakan polisakarida kedua terbesar di alam setelah selulosa dan mempunyai potensi ekonomi tersendiri terlebih bila telah diuraikan menjadi bahan yang bermanfaat. Penguraian xilan membutuhkan kerja dari kombinasi beberapa enzim dengan endoxilanase (endo-1,4-β-D-xilanase, EC 3.2.1.8) sebagai pendahulu dalam mendegradasi xilan menjadi xilooligosakarida. Salah satu bakteri yang mampu menghasilkan endoxilanase adalah Streptomyces costaricanus 45I-3 koleksi Dr. Ir. Yulin Lestari, Bagian Mikrobiologi Departemen Biologi IPB yang diisolasi dari tanah gambut di Kalimantan. Namun produksi xilanase S. costaricanus 45I-3 secara komersial kurang efisien dan ekonomis disebabkan pertumbuhannya yang lambat bila dibandingkan dengan bakteri pada umumnya. Pendekatan molekuler memungkinkan gen penyandi endoxilanase S. costaricanus 45I-3 diisolasi dan dieskpresikan ke dalam inang yang sesuai untuk mempercepat pertumbuhan dan produksi enzim. Beberapa metode isolasi gen penyandi endoxilanase dari bakteri telah dilaporkan. Salah satu metode isolasi gen penyandi endoxilanase yang tercepat adalah dengan PCR. Penelitian ini bertujuan melakukan isolasi fragmen gen penyandi endoxilanase dari S. costaricanus 45I-3 menggunakan pendekatan PCR yang dilanjutkan dengan penentuan dan analisis urutan DNA. Penelitian ini dilakukan di Laboratorium Bioteknologi Hewan dan Biomedis dan Laboratorium BIORIN (Biotechnology Research Indonesian-The Netherlands), Pusat Penelitian Sumberdaya Hayati dan Bioteknologi (PPSHB) Institut Pertanian Bogor dari bulan Agustus 2008 sampai dengan Mei 2010. Tahapan penelitian yaitu peremajaan isolat S. costaricanus 45I-3, isolasi DNA kromosom, perancangan primer, PCR, ligasi dengan pGEM-T Easy, introduksi ke E. coli DH5α kompeten, isolasi dan verifikasi plasmid rekombinan, pengurutan DNA dan analisis sekuen. Perancangan primer untuk mengamplifikasi gen endoxilanase S. costaricanus 45I- 3 dilakukan berdasarkan data urutan nukleotida gen endoxilanase dari genus Streptomyces yang diperoleh di Gen Bank (http://www.ebi.ac.uk/embl/). Wilayah konservatif dalam gen penyandi endoxilanase Streptomyces dicari melalui penjajaran urutan asam amino maupun nukleotida menggunakan program Clustal W. Primer dirancang menggunakan program Primer3 (http://frodo.wi.mit.edu/cgi-bin/primer3.cgi). Hasil perancangan diperiksa kualitasnya dengan program IDT (http://www.idtdna.com/ SciTools/SciTools.aspx). Rancangan primer diuji spesifitasnya dengan program BLASTn (http://www.ncbi.nlm.nih.gov/BLAST/)....dst
Keyword: Streptomyces costaricanus 45I-3 isolation of endoxylanase gene, design of PCR primer

Judul: Kloning Gen Xilanase Termozim Dari Streptomyces costaricanus 45I-3
Abstrak: Biopolymer xylan has a great potential to produce useful end product such as xylose. Xylanases is a group of enzyme that has ability to hydrolyse xylan or polymer of xyloses and xylooligosaccharides. Complete hydrolysis of xylans involves the synergistic action of a xylanolytic enzymes, including ß-xylanase, ß-xylosidase, -glucuronidase, -L-arabinofuranosidase, and acetyl xylan esterase. The aims of this research were to isolate xylanase gene from Streptomyces costaricanus 45I-3 and to clone this gene into competence Escherichia coli DH5 . Genomic DNA was obtained from S. costaricanus 45I-3 that have known has ability to produce thermostabile extracellular xylanase. Genomic DNA was partially digested with restriction enzyme Sau3A1. Genomic DNA fragments of size 4-10 kb were inserted at BamHI site in pBluescript II KS (+) vector and transformed into E. coli DH5 . Based on blue-white selection approximately 12000 recombinant colonies were obtained. The presence of xylanase gene was identified by screening employing congored plate clearance assay. One positive clone containing the xylanase gene was confirmed and was designated as pHS11. Preliminary characterization of pHS11 using EcoRI showed that it contained a 6,0 kb DNA insert. Xylanase were produced has xylanase spesific activity 6,393 U/mg, -xylosidase activity 0,208 U/ml, arabinofuranosidase activity 0,079 U/ml and acetyl xylan esterase activity 0,063 U/ml as well.
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Judul: Tinjauan Matematis pada Model Makroskopik dan Mikroskopik Arus Lalu-lintas
Abstrak: Traffic flow phenomenon can be described through mathematical model such as continuous dynamic model with an ordinary differential equation so that it can be solved with integral factors. In this paper three simple models of traffic flow are discussed, i.e, two macroscopic and one microscopic models. Macroscopic model formulates dynamics of the traffic flow that occurs on a large number of vehicles on a road. While the microscopic model explains drivers’ behavior in their interaction with other vehicles ahead, i.e, car-following model. This paper shows the existence of ordinary differential equation found in the traffic flow model and indicates some different representations in the context of the same model. It also reviews a simple model of traffic flow along a single link, which leads to some unexpected results, i.e, it can express the solution model in term of link outflows as well as trip time. In the microscopic model, simulation is done to illustrate the behavior of the drivers with a sensitivity coefficient as a benchmark parameter.
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