Judul: Pelacakan Gen Serupa hemA dan hemT Pada Sejumlah Isolat Bakteri Fotosintetik Anoksigenik dan Beberapa Contoh Tanah dari Indonesia
Abstrak: Gen hemA dan hemT adalah gen penyandi isozim asarn 6- arninolevulinat (ALA)-sintase pada Rhodobacter sphaeroides 2.4.1. Gen tersebut rnerupakan bahan genetik penting dalam usaha peningkatan produksi ALA rnelalui rekayasa genetik, karena ALA-sintase rnerupakan enzim kunci dalarn biosintesis ALA rnelalui lintasan C,. Penelitian ini bertujuan untuk rnelacak gen serupa hemA dan hemT dari 20 isolat bakteri fotosintetik anoksigenik (BFA) dan empat contoh tanah dari daerah Bogor. Pelacakan dilakukan dengan teknik hibridisasi Southern dan hibridisasi Dot Blot. Teknik hibridisasi Southern digunakan untuk rnelacak gen serupa hemA dan hemT pada 20 isolat BFA sedangkan hibridisasi Dot Blot digunakan untuk rnelacak kedua gen tersebut pada contoh tanah. Pelacak yang digunakan adalah fragrnen gen hemA dan hemT.
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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: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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