Judul: Introduksi Gen Penyandi AHL-Laktonase (aiiA) Bacillus cereus INT1c ke dalam Agrobacterium tumefaciens AGL 1.
Abstrak: Bakteri menggunakan mekanisme quorum sensing (QS) dalam berkoordinasi untuk melakukan suatu proses tertentu melalui perantara molekul sinyal asil homoserin lakton (AHL). Bakteri fitopatogen umumnya menggunakan mekanisme QS untuk mengekspresikan gen virulen pada saat menginfeksi tanaman. Penghambatan ekspresi gen virulen tersebut dapat dilakukan dengan mendegradasi senyawa AHL menggunakan AHL-laktonase. AHL-laktonase merupakan kelompok enzim yang berfungsi untuk menghidrolisis cincin lakton pada molekul AHL. Enzim ini umumnya ditemukan pada kelompok Bacillus spp. dan disandikan oleh gen aiiA. Penelitian ini bertujuan mengintroduksi gen penyandi AHL-Laktonase (aiiA) dari isolat Bacillus cereus INT1c dalam E.coli DH5α transforman ke dalam Agrobacterium tumefaciens AGL 1. Gen aiiA dari isolat Bacillus cereus INT1c dalam E.coli DH5α rekombinan berhasil diintroduksikan ke dalam sel A. tumefaciens AGL 1 melalui plasmid vektor pCambia 2300. Pemotongan plasmid rekombinan dengan menggunakan enzim Nco I dan Bgl II menunjukkan adanya fragmen DNA berukuran 8743 pb (pCambia 2300) dan 800 pb (gen aiiA) pada gel agarosa 1.0%. Hasil ini membuktikan bahwa plasmid rekombinan berhasil diintroduksikan dan telah diperbanyak di dalam sel A. tumefaciens AGL 1 transforman.
Keyword: Agrobacterium tumefaciens, AHL- laktonase, aiiA, Bacillus sp., introduksi, transformasi

Judul: Introduksi Gen Penyandi AHL Laktonase Asal Bacillus thuringensis SGT3g ke dalam Agrobacterium tumefaciens LBA4404.
Abstrak: Bakteri memanfaatkan quorum sensing (QS) untuk regulasi biofilm, faktor virulen, sintesis antibiotik, sporulasi, dan bioluminesen. Salah satu prinsip pengendalian virulensi bakteri fitopatogen dengan dasar QS adalah mencegah akumulasi AHL dengan mendegradasi molekul sinyal tersebut. Salah satu enzim pendegradasi AHL adalah enzim Acyl Homoserine Lactonase. AHL-laktonase sebagai salah satu enzim anti-QS dapat digunakan sebagai alternatif dalam pengendalian bakteri fitopatogen. Enzim ini umumnya ditemukan pada kelompok Bacillus dan disandikan oleh gen aiiA. Penelitian ini bertujuan untuk mengintroduksi gen penyandi AHL Laktonase pada Agrobacterium tumefaciens LBA4404 asal Bacillus thuringensis SGT3g. Amplifikasi gen AHL-laktonase dari isolat E.coli rekombinan yang membawa gen aiiA dari Bacillus thuringensis SGT3g dengan menggunakan primer aiiA mendapatkan pita DNA berukuran 800 bp. Gen aiiA asal Bacillus thuringensis SGT3g disisipkan ke dalam plasmid pCambia 2300 pada situs restriksi NcoI dan BglII. Analisa elektroforesis hasil restriksi pCambia 2300 rekombinan, plasmid pC-TE01, menggunakan enzim restriksi NcoI dan BglII menunjukkan adanya fragmen DNA berukuran 8743 bp (pCambia 2300) dan 800 bp (DNA sisipan aiiA) pada gel agarosa 1,5%.
Keyword: AHL-Laktonase, gen aiiA, Bacillus thuringensis, pCambia 2300

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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