Judul: Identification of Biomarker Peptide Gelatin Raw Materials through Mass Spectroscopy using Bioinformatics Techniques
Abstrak: Gelatin, a partial hydrolysis product of animal collagen has been widely used in Indonesia processing industry. The source of gelatin, however, is strictly regulated due to religious concern. Thus, the method that could differentiate the source of gelatin is needed. This research was aimed to predict biomarker peptides using bioinformatics approach that could be used to differentiate the source of gelatin by means of mass spectrometry. Collagen sequences from cattle, pigs, chickens, and fish were obtained from the UniProt database. The sequences were in silico digested using trypsin and chymotrypsin in PeptideMass software. The resulting peptides were filtered following the criteria for mass spectrometry. In general, trypsin digestion produced higher number of specific peptides compared to that of chymotrypsin enzyme. The number of peptide sequences resulting from hydrolysis with the chymotrypsin indicates the enzyme is less specific in cutting protein than the trypsin enzyme. Trypsin is more suitable for finding biomarkers than chymotrypsin. Some of the specific peptides detected can be used to differentiate the species from which gelatin is derived.
Keyword: bioinformatics, enzyme, gelatin, mass spectrometry, specific peptide

Judul: Identification of Pork DNA Fragments in Gelatin Samples Using Real Time Polymerase Chain Reaction (qPCR) methods
Abstrak: Gelatin merupakan suatu jenis protein yang diperoleh melalui hidrolisis parsial kolagen dari kulit dan tulang hewan yang memiliki banyak fungsi untuk keperluan berbagai industri. Kebutuhan gelatin dalam negeri umumnya dipenuhi secara impor. Gelatin yang berasal dari kulit babi adalah yang tertinggi dari total produksi gelatin di dunia. Produk babi dan turunannya termasuk gelatin babi dilarang untuk dikonsumsi oleh Muslim, sehingga diperlukan adanya pengujian untuk mengetahui sumber gelatin. Penelitian ini bertujuan untuk mengidentifikasi fragmen DNA babi pada sampel gelatin dengan menggunakan metode real time Polymerase Chain Reaction (qPCR) dengan primer dan probe sudah termasuk ke dalam master mix mericon Pig Kit. Sebanyak 53 sampel gelatin diekstraksi sesuai dengan prosedur standar dari DNeasy mericon Food Manual Book. Hasil ekstraksi sampel gelatin dikuantifikasi menggunakan nanodrop spectrofotometer 2000c dan diperiksa menggunakan kit komersial. Proses amplifikasi dilakukan sesuai dengan prosedur standar dari DNeasy mericon Pig Kit Handbook. Hasil uji qPCR mampu mengidentifikasi adanya fragmen DNA babi pada sampel gelatin yang ditunjukkan dengan nilai Ct<45. Sebanyak 4 sampel gelatin dari 53 sampel positif mengandung DNA babi, sedangkan 49 sampel gelatin menunjukkan hasil negatif. Uji qPCR dapat dijadikan sebagai metode pengujian untuk mengidentifikasi adanya fragmen DNA babi pada sampel gelatin., Gelatin is a protein obtained by hydrolysis of collagen from animal skin and bone that has great importance in many industry. Domestic gelatin is generally obtained by import. The raw materials used in gelatin production are highly from porcine sources. Porcine gelatin is forbidden for Muslim. For this reason, analytical methods to detect gelatin are needed to make sure the source of gelatin. The aim of this research was to identify the presence of pork DNA fragments in gelatin by real time PCR (qPCR) methods. The primer and probes of qPCR were included in mericon Pig Kit master mix. The samples consisted of 53 gelatins. They were extrated according to the procedure of DNeasy mericon Food Manual Book. The result of extracted gelatins was quantified by nanodrop spectrofotometer 2000c and examined by a commercial kit. The amplification process of gelatins was carried out according to the procedure of DNeasy mericon Pig Kit Handbook. The result showed that gelatins with pork DNA can be identified by Ct value<45. There were 4 samples positive contained pork DNA, while 49 samples were negatives. The qPCR methods can be used to identify the presence of pork DNA fragments in gelatin samples.
Keyword: DNA, gelatin, pork, qPCR

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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