Judul: Isolasi dan Kloning Gen Selulase dari Bakteri Rumen Sapi.
Abstrak: Cellulases are the enzymes that hydrolize cellulosic biomass and are produced by the microorganisms that grow over cellulosic matters. The objective of this research was to isolate and clone cellulase gene from cellulose-degrading bacteria of bovine rumen. Cellulose-degrading bacteria were isolated from rumen fluid using a selective medium. Total RNA was isolated from selected colony having cellulose degrading activity and it was used as a template for cDNA construction using reverse transcriptase polymerase chain reaction (RT-PCR) technique. The resulted cDNA was used as a template for PCR amplification of cellulose gene using specific primers. The cellulose gene candidate obtained was cloned into the pGEM-T-Easy vector followed by determination of its nucleotide sequence. The nucleotide sequence generated was aligned with sequences of cellulase genes from GenBank. A number of isolates of rumen bacteria showed cellulase activity and the isolate CR-8 was selected for further analysis. Total RNA was successfully isolated from isolate CR-8 indicated by the presence of two intense bands of ribosomal RNA (23S and 16S). The reverse transcription process was successful and amplification of cellulase gene using the specific primer F1 and R1 resulted in a DNA fragment of 1900 bp as a candidate of cellulase gene. The fragment was successfuly cloned into the pGEM-T-Easy vector, and the resulted recombinant plasmid was successfully introduced into the E. coli cells. Nucleotide sequence analysis suggested that the isolated cellulase gene shares 99% homology with the endo-1,6-beta-glucanase of T. harzianum.
Keyword: cellulase, clone, GenBank, rumen bacteria

Judul: Identifikasi Bakteri Selulolitik Asal Tanah Situ Gede dengan Teknik Genetika Molekuler.
Abstrak: Cellulose is a biopolymer in nature which is dominant agricultural waste. Many practices degrade cellulose into glucose molecules by using cellulase enzyme. This research aim to identify the cellulolytic bacteria and to test cellulase activities. The methods are platting isolates, halo zone testing, DNA isolation, visualization of DNA fragmen by electrophoresis, 16S rDNA gene amplification by Polymerase Chain Reaction (PCR), 16S rDNA gene divesity analysis with restriction enzymes, DNA sequensing analysis, and enzymatic assay using CMC selective media. Six isolates were analyzed by restriction enzyme and showed three diversity of based, its differences by size. The size of the bases are 1500 bp, 850 bp, and <850 bp. Sequensing DNA by GeneBank in NCBI web are 85% indentical between Cellvibrio fibrivorans to isolate D714 and then 81% identical to Cellvibrio gandavensis to isolate J531. Enzyme activities of isolates D714, D533, J731, and J531 has been tested enzyme to get the highest activity on seventh day is 0.1054 IU/mL, 0.0996 IU/mL, 0.101 IU/mL, and 0.9689 IU/mL.
Keyword: cellulolytic bacteria, cellulase enzyme, gene 16S rDNA

Judul: Penghambatan Masuknya Pendatang Baru Dalam Pasar Spasial
Abstrak: Monopoli dapat bertahan karena perusahaan-perusahaan lain menganggap tidak menguntungkan untuk masuk pasar atau karena memang terhambat (dihambat) untuk masuk pasar. Ancaman masuknya pendatang baru membuat perusahaan monopoli yang sudah ada berusaha menyusun strategi baru agar dapat bertahan menghadapi persaingan dengan pendatang barn. Jika hambatan masuk pasar (barriers to entry) besar atau dengan kata lain pendatang baru memperkirakan akan ada penghambatan keras dari perusahaan monopoli yang sudah ada, maka ancaman masuknya pendatang baru akan rendah dan demikian sebaliknya. Studi ini menganalisis persaingan antara monopolis (the incumbent) dengan calon pendatang baru (potential entrant) dalam kerangka model permainan.
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