Judul: Analisis keragaman genetik dan sintasan sejumlah isolat bekteri fotosintetik anoksigenik asal laut
Abstrak: Eighty isolates of anoxygenic photosynthetic bacte- ria were isolated from 49 samples collected from a number of Indonesian seashores. All of the isolates showed similar color (i.e. photosynthetically in red to brownish red) when grown Sea Water Complete (SWC) medium. under illumination of tungsten light (± 200 lux). Many of the isolates were gram-negative, rod shape bacteria. However, genetic analysis employing Asel-schizotyping of 45 selected isolates indicated extensive genetic diversi- ty which apparently did not show any biogeographic relat- edness. A number their survival of selected isolates in sterile sea water were examined for supplemented with peptone (0,1 g/1) and yeast extract (0,02 g/1). All of the isolates demonstrated significant growth until 5 days of incubation and most of them maintained their viability up to 7 days of incubation. However, SKX121 is the only isolate which could maintain its viability up to 2 x 109 cell/ml after 7 days of incubation. From 47 isolates examined, 35 isolates were signifi- cantly more tolerant to Na2S (up to 100 µg/ml than isolate MW4, a reference isolate which has been known as sulphide tolerant anoxygenic photosynthetic bacteria.
Keyword: keragaman genetik, Bakteri fotosintetik, laut

Judul: Analisis spektra dan profil DNA Genom bakteri fotosintetik anoksigenik asal tanah sawah
Abstrak: Bakteri fotosintetik anoksigenik (BFA) memiliki kemampuan menambat N₂ yang pada gilirannya dapat disumbangkan sebagai alternatif nutrisi N bagi tanaman khususnya padi sawah. Selain itu bakteri ini mampu memanfaatkan energi cahaya pada bagian infra merah dari spektrum yang tidak digunakan oleh tanaman. Berdasarkan kemungkinan pemanfaatan bakteri di susunlah penelitian yang bertujuan melihat keragaman bakteri fotosintetik anoksigenik (BFA) asal tanah sawah melalui analisis spektra protein dan analisis profil DNA genom. Sebanyak 59 isolat telah diperoleh dari tanah sawah yang berasal dari sejumlah lokasi di daerah Cirebon, Indramayu, Krawang, Sukabumi, Bandung, Cianjur, Bogor, Riau dan Pacitan. Isolat ditumbuhkan pada media minimal sistrom cair 50%, pH 7.2, pada kondisi suhu 32°C, anaerob dan pemberian cahaya terus menerus selama 7 hari. Isolat BFA yang diperoleh umumnya berbentuk batang, dengan warna kultur merah hingga kecoklatan, bersifat gram negatif dan motil. Dari 4 isolat BFA yang diuji pada konsentrasi protein 0.27 mg/ml dan panjang gelombang 200-900 nm, tampak pola spektra yang berbeda-beda. Pola spektra BDG 12 mirip dengan Rhodobacter sphaeroides 2.4.1(R.s 2.4.1), sedangkan IDR 34 mirip dengan CJR 34. Kemiripan tersebut diperkuat oleh hasil analisis elektroforesis medan berpulsa yang menggunakan enzim Ase I dengan waktu pulsa 10-50 detik, waktu pemisahan 20 jam, tegangan listrik 180 volt dan agarosa 1%. Hasil pemotongan Ase I pada DNA genom utuh isolat BDG 12 menunjukan kemiripan dengan R.s 2.4.1 pada potongan DNA yang berukuran 360 - 3 kilo pasang basa. Sementara 8 isolat lain yang diuji menunjukan keragaman genetik yang tinggi.
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Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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