Judul: Screening and characterization of protease inhibitor from bacteria associated with sponge Jaspis sp
Abstrak: Tiga galur dari 138 isolat bakteri yang berasosiasi dengan spons dari Waisai, Pulau Raja Ampat, Propinsi Papua Barat, Indonesia, diketahui mampu menghasilkan aktivitas penghambatan terhadap subtilisin (protease serin), termolisin (protease logam), dan ekstrak kasar dari bakteri patogen Eschericia coli enteropathogenic (EPEC) K.1.1, Staphylococcus aureus, dan Pseudomonas aeruginosa. Isolat-isolat tersebut dinamakan sebagai SAB S-12, SAB S-21, and SAB S-17. Metode agar-agar lapis ganda yang terdiri atas lapis kasein dan SWC (sea water complete) digunakan untuk menapis produsen penghambat protease terhadap kelompok bakteri patogen penghasil protease, seperti EPEC K.1.1, S. aureus, dan P. Aeruginosa. Dari ketiga isolat penghasil penghambat protease, isolat SAB S-12 tidak menghasilkan zona penghambatan, hal ini mengindikasikan bahwa galur tersebut memiliki aktivitas penghambatan terbesar. Isolat SAB S-12 memiliki aktivitas penghambatan terbesar terhadap termolisin dan enzim ekstrak kasar dari kelompok bakteri patogen berturut-turut sebesar 91.570% dan 98.846%. Kemudian, isolat SAB S- 21 memiliki aktivitas penghambatan terbesar terhadap termolisin sebesar 70.370%. Kondisi pertumbuhan optimum dari ketiga galur tersebut pada rentang pH 7.0-8.0 dan rentang suhu 40- 50˚C pada media SWC. Semua galur penghambat protease termasuk ke dalam kelompok bakteri Gram-negatif dan berbentuk batang.
Keyword: Streptomyces, Escherichia coli, Aplysina aerophobia

Judul: Screening and characterization of protease inhibitor from bacteria-associated with spone, from Pulau Panggang waters, Seribu island
Abstrak: The important causing foodborne disease are Staphylococcus aureus, Escherichia coli, Listeria spp. and Pseudomonas aeruginosa. Protease produced by these bacteria are involved in the molecular mechanisms of the disease. Therefore, there has been rapidly increase concern on proteases as medical target for bacterium diseases. Various sponges has been reported to produce protease inhibitor which could inhibit protease activity of pathogenic bacteria.
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Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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