Judul: Eksplorasi Protein dari Sponge Asal Perairan Pulau Nias dan Binuangeun yang Mengkatalisis Polimerisasi Silika
Abstrak: Silica, polymerized silicon dioxide, was widely used as raw materials for industries, such as food industry, semiconductor, electronic and medical equipment. Marine sponges (Phylum porifera) were living system that can produce a remarkable diversity of nanostructured silicates at ambient temperature and near-neutral pH. In contrast to living system, synthesis of these materials in industry require extreme of temperature, pressure, and pH with addition surfactant that can cause environmental pollution. Isolating protein that can catalyze nanostructured silica polymerization will make a new route for silica development under mild conditions using protein/enzyme biocatalyst. This research was aimed to extract and analyze protein from Nias Island Sea sponges and Binuangeun Sea sponges and to study their activity to polymerize tetraethoxyorthosilicate (TEOS). Protein in silica spicule of sponge was isolated by collecting silica spicule and soaked in HF/NH4F buffer (pH 5,0) for dissolving silica and releasing this protein. Then, protein was dialyzed and centrifuged. Activity of this protein to polymerize substrate tetraethoxyorthosilicate was measured by colorimetric molybdate assay. Protein of Sponge ST1 (from Binuangeun Sea) and protein of Sponge ST3 (from Nias Island Sea) have the same moleculer weight about 21.4 kDa and the same shape (filament) and size. Both of them have the length approximately 0,1 mm and diameter 10 mm. Protein of Sponge ST1 (250 ml, protein concentration less than 5 mg/ml) could polymerize 15,9 μmol TEOS after 12 hours reaction at room temperature and near-neutral pH and protein of Sponge ST3 could polymerize 3,0 μmol TEOS in the same reaction conditions. Silica formed from polymerization reaction by protein Sponge ST1 during 48 hours, coated this protein and increased its diameter four times. Sponge ST5, ST6 and ST7 which have unique microscleres silica spicule were potential to become sources of protein that can catalyze unique shape of biosilica. Sponges which have no silica spicule such as Sponge St8 and ST9 were not potential to become protein sources.
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Judul: Screening and characterization of protease inhibitor from  bacteria-associated with sponge, from pulau Panggang waters, Seribu islands
Abstrak: The important causing cause foodborne diseases are Staphylococcus aureus, Escherichia coli, Listeria spp. and Pseudomonas aeruginosa. Protease produced by these bacteria are involved in the molecular mechanisms of the diseases. 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. The previous research showed that bacteria-associated with sponge could produce bioactive compound similar with their host. Therefore, there is a possibility that the bacteria also produce protease inhibitor.
Keyword: sexual behavior, marine commodity, nuclear magnetic resonance, spermatozoa quality, essential amino acids

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular