Judul: Isolasi dan Karakterisasi Protein Ikan Tongkol (Auxis thazard), Kerang Hijau (Perna viridis)
Abstrak: Seafoods including fish, crustaceans and shellfish play an important role in human nutrition. However, it is also recognised as an important cause of food allergies, especially in coastal countries, including Indonesia. Treatments of these diseases still rely on avoiding the sources of the alergens, however it can also cause malnutrition which is also dangerous to health. To determine the specific food protein causing allergic reactions, cutie test was performed using isolate food protein. Until the present time, Indonesia still imports kits containing isolate proteins for food allergy diagnosis, therefore effort to locally produce the kit will reduce health cost for patients with allergic diseases. The objective of this study was to produce seafoods protein extract that is potential to be used as isolate of allergens for food allergy diagnosis. Two extract sarcoplasmic and myofibril protein were obtained from fish, shrimp and mussel by extraction in phosphate buffer with diference ionic strength Protein profile were then detected by means of sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). IgE binding pattern was analyzed by using ELISA and immunoblotting using sera from 20 respondents with histories of food allergy. The result of the study showed that samples of seafood extract protein consist of several protein with various molecular weight in the range about 14 to 143 kDa. The component were identified as tropomyosin (34-38 kDa), parvalbumin (~12 kDa), myosin light chain (~17.5 kDa) and arginin kinase (40 kDa) which are major allergens in seafoods. Further analysis with ELISA showed that the seafood protein extracts contained several IgE-binding proteins. Immunoblot of three extract samples from seafoods showed that components identified as allergens to each allergic subject have different molecular weight. The results demonstrated that crude extract could be directly used as isolate allergen for diagnostic test allergy (skin prick test) without isolating the major allergen components.
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Judul: Optimasi Metode Ekstraksi dalam Identifikasi dan Karakterisasi Molekuler Protein Penyebab Alergi pada Terasi
Abstrak: Terasi sebagai penyedap makanan digemari oleh masyarakat, namun terasi mengandung alergen tropomiosin dari udang yang berpotensi menyebabkan alergi pada sebagian orang. Pemilihan buffer yang tepat diperlukan untuk mengidentifikasi alergen pada terasi dengan baik. Tujuan penelitian yaitu menentukan buffer ekstraksi yang baik dalam memperoleh protein udang pada terasi sehingga dapat diidentifikasi dan dikarakterisasi. Sampel penelitian terdiri dari satu jenis udang rebon dan delapan jenis terasi yang berbeda. Metode ekstraksi terdiri atas tiga jenis buffer dengan pH berbeda yaitu pH 7,4 phosphate buffered saline, pH 8,5 coca solution, dan pH 10,6 carbonate buffered saline yang dilakukan kepada sembilan sampel. Konsentrasi dan profil protein dianalisis dengan uji Bradford dan SDS-PAGE. Konsentrasi protein menggunakan tiga buffer yang berbeda menunjukkan hasil yang bervariasi. Analisis SDS-PAGE pada sampel memiliki bobot molekul berkisar 15-200 kDa. Hasil ekstraksi terbaik didapatkan pada penggunaan buffer CBS. Tropomiosin tidak teridentifikasi pada sampel terasi. Pemrosesan udang menjadi olahan terasi dapat menurunkan alergen udang., Terasi as a food flavoring is popular among people, but it contains the tropomyosin allergen from shrimp, which has the potential to cause allergies in some people. The right buffer selection needs to be used to identify allergens in shrimp paste correctly. This research aimed to determine a suitable extraction buffer for obtaining shrimp protein in shrimp paste so that it could be identified and characterized. The research sample included one type of rebon shrimp and eight different shrimp pastes. The extraction method used three types of buffers with different pH, phosphate buffered saline pH 7.4, coca solution pH 8.5, and carbonate buffered saline pH 10.6 which were carried out on nine samples. The protein concentration and profile were determined using the Bradford test and SDS-PAGE. Protein concentration using three different buffers showed varying results. SDS-PAGE analysis of the samples revealed molecular weights ranging from 15-200 kDa. The best extraction results were obtained by using the CBS buffer. Tropomyosin was not identified in the sample of shrimp paste. Shrimp allergens can be reduced by processing shrimp into processed shrimp paste.
Keyword: alergen, bobot molekul, ekstraksi, protein, tropomiosin

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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