Judul: Isolasi Dan Identifikasi Bakteri Endofit Tumbuhan Nyawai (Ficus Variegata Blume) Serta Analisis Senyawa Antibakteri.
Abstrak: Ficus variegata Blume merupakan tumbuhan obat yang mengandung senyawa antibakteri. Bakteri endofit merupakan bakteri yang hidup bersimbiosis dengan tanaman. Beberapa spesies bakteri endofit telah diteliti memiliki kemampuan menghasilkan senyawa bioaktif, salah satunya antibakteri. Tujuan penelitian ini adalah mengisolasi, menguji aktivitas antibakteri, mengidentifikasi bakteri endofit dari tumbuhan nyawai, serta menganalisis senyawa antibakteri yang dihasilkan oleh isolat bakteri potensial menggunakan GC-MS. Tahap awal pada penelitian ini yaitu isolasi bakteri endofit dari tumbuhan nyawai. Isolat yang dihasilkan kemudian diuji aktivitas antibakterinya terhadap Staphylococcus aureus, Escherichia coli, Bacillus subtilis, dan Pseudomonas aeruginosa. Isolat yang mampu menghambat semua bakteri uji dinamakan isolat potensial. Identifikasi dilakukan secara morfologi, biokimia, dan molekuler berdasarkan sekuen 16S rRNA. Isolat potensial kemudian difermentasi dalam media nutrient broth (NB) selama 48 jam. Supernatan hasil fermentasi diekstraksi dengan etil asetat. Selanjutnya, analisis senyawa antibakteri yang dihasilkan oleh bakteri endofit dilakukan dengan menggunakan GC-MS. Sebanyak 29 isolat bakteri endofit diperoleh dari Ficus variegata Blume. Berdasarkan uji aktivitas antibakteri, isolat bakteri endofit BH2 mampu menghambat pertumbuhan semua bakteri uji. Hasil identifikasi morfologi dan aktivitas biokimia menunjukkan bahwa bakteri isolat BH2 merupakan Pseudomonas sp. Analisis sekuen 16S rRNA menggunakan BLAST menunjukkan isolate BH2 memiliki presentase kemiripan dengan Pseudomonas aeruginosa strain SV1 sebesar 99%. Hasil GC-MS menunjukkan bahwa senyawa aktif yang diduga berperan sebagai antibakteri dari ekstrak etil asetat isolat BH2 diantaranya asam nonanoat, dokosan, oktadekan, asam tetrakosanoat, asam heksadekanoat, asam 9-oktadekanoat, asam 1,2-benzenedikarboksilat bis (2-etilheksil) ester, tetradekan, eikosan, nonakosan, dan triakontan.
Keyword: Bakteri endofit, Ficus variegata Blume, Pseudomonas aeruginosa, GC-MS, 16S rRNA

Judul: Isolasi Dan Identifikasi Bakteri Endofit Dari Daun Sirsak (Annona Muricata L.) Penghasil Senyawa Antibakteri
Abstrak: Bakteri endofit merupakan mikroorganisme yang hidup pada jaringan tanaman secara simbiosis mutualisme. Beberapa jenis bakteri endofit diketahui mampu menghasilkan senyawa aktif yang bersifat antibiotik. Tujuan dari penelitian ini adalah mengisolasi bakteri endofit dari daun tanaman sirsak (Annona muricata L.) yang memiliki aktivitas antibakteri terhadap bakteri penyebab penyakit infeksi dan mengidentifikasi bakteri tersebut secara genetik berdasarkan gen 16S rDNA. Bakteri patogen yang diujikan terdiri atas 5 spesies yaitu Escherichia coli, Pseudomonas aerroginosa, Staphylococcus mutans, dan Streptococcus aureus. Isolat bakteri endofit dengan kode G42 potensial menghambat keempat jenis bakteri uji sedangkan isolat S42 dan S54 berhasil menghambat 3 jenis bakteri uji. Berdasarkan analisis gen 16S rDNA, isolat G42 memiliki persentase kemiripan sebesar 93% dengan Plautia stali symbiont.
Keyword: antibakteri, bakteri endofit, sirsak, 16S rDNA

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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