Judul: Karakterisasi Enzim β-Glukanase dari Bacillus subtilis Menggunakan Metode in Vitro dan in Silico
Abstrak: Enzim β-glukanase merupakan protein enzim yang dapat menghidrolisis β-glukan, salah satu komponen utama penyusun dinding sel jamur dan menjadi target pengendalian hayati jamur fitopatogenik Protein enzim ini dihasilkan oleh beberapa bakteri salah satunya adalah Bacillus subtilis. Penelitian ini bertujuan melakukan karakterisasi enzim β-glukanase dan aktivitas antagonisnya terhadap Fusarium oxysporum penyebab layu tanaman, serta memahami sifat dan fungsi protein enzim β-glukanase dengan melihat struktur 3D nya. Penelitian ini menganalisis secara in vitro pengaruh faktor-faktor eksternal terhadap aktivitas enzim β-glukanase, penentuan laju reaksi enzim serta analisis in silico dengan pemodelan struktur dan analisis docking. Hasil penelitian menunjukkan bahwa aktivitas enzim β-glukanase setelah proses pengendapan dengan ammonium sulfat 60% menjadi lebih tinggi dibandingkan dengan ekstrak kasar. Tingkat kemurnian yang diperoleh sebesar 1.43 kali dengan yield sebesar 37.29%. Hasil selanjutnya, enzim β-glukanase dikarakterisasi menggunakan beberapa parameter seperti logam, inhibitor dan laju reaksi. Enzim β-glukanase dari isolat B.subtilis W3.15 mengalami peningkatan aktivitas saat ditambahkan ion logam Ca2+, sehingga ion logam tersebut dapat dikatakan sebagai kofaktor. Saat penambahan ion logam lainnya, aktivitas enzim mengalami penurunan, begitu pula ketika ditambahkan EDTA. Perhitungan laju reaksi enzim β-glukanase menghasilkan nilai kecepatan maksimum (Vmax) sebesar 0.017 µmol/L.jam dan nilai Km yaitu 0.99 µmol/L. Isolat B. subtilis W3.15 kemudian diisolasi DNAnya untuk mendapatkan sekuen DNA yang menyandi protein enzim β-glukanase. Sekuen DNA tersebut diubah menjadi sekuen asam amino kemudian dilakukan pemodelan struktur 3D menggunakan bantuan webserver SWISS-MODEL dengan metode homology modeling. Pemodelan enzim β-glukanase berdasarkan template dari model protein enzim β-glukanase dengan kode PDB 3o5s. Hasil pensejajaran sekuen dan visualisasi model cukup baik yang ditunjukkan dengan model memiliki nilai Ramachandran Plot pada daerah favoured sebesar 91,10%, skor MolProbity sebesar 0.95 dan nilai QMEAN 0.90±0.06. Model enzim β-glukanase di-docking menggunakan program PLANTS1.1 dengan ligan native ligand B3P, 1,4- β-D-Glucan, D-glucose, β-D-Glucan from oat, dan N-Acetil glucosamine. Hasil analisis docking menunjukkan bahwa ligan β-glukan (β-D-Glukan dari oat) yang digunakan sebagai substrat dalam kultivasi isolat B. subtilis W3.15 memiliki skor PLANTSCHEMPLP dan nilai prediksi afinitas enzim paling rendah yaitu -97.8514 dan 0.85 residu asam amino yang berikatan dengan ligan, yaitu GLU133, GLU137, ASN149, GLN147, GLU159, dan TRP220. Berdasarkan pada penelitian ini, maka ligan β-D-Glucan from oat yang diuji secara in silico dan in vitro merupakan substrat yang memiliki hasil aktivitas enzim β-glukanse B. subtilis W3.15 yang terbaik dibandingkan substrat lainnya
Keyword: β-D-Glucan from oat, docking, PLANTS 1.1, Km, Vmax

Judul: Enzyme Activity of β-1,3-Glucanase from Streptomyces spp. Rhizosphere and Cloning of its Encoding Gene
Abstrak: Enzim β-1,3-glukanase merupakan salah satu enzim yang mampu menghidrolisis glukan penyusun dinding sel cendawan fitopatogen. Aktinomiset rizosfer jagung dari kelompok Streptomyces spp. diduga mampu memproduksi enzim yang memiliki aktivitas glukanolitik dan berpotensi untuk dikembangkan sebagai agen biokontrol cendawan fitopatogen. Penelitian ini bertujuan menganalisis aktivitas enzim glukanase secara kuantitatif dua isolat Streptomyces spp. dengan indeks glukanolitik tertinggi pada penelitian sebelumnya dan mengidentifikasi gen penyandinya. Metode penelitian yang dilakukan meliputi uji aktivitas glukanase secara kuantitatif, amplifikasi gen endo-β-1,3-glukanase (bglS), kloning, konfirmasi hasil kloning, sekuensing, analisis fenetik, dan prediksi model protein. Aktivitas spesifik enzim isolat S. collinus ARJ38 lebih tinggi dari S. tritolerans ARJ32, yakni sebesar 41,599 U/mg pada waktu inkubasi hari ke-8. Keberadaan gen penyandi bglS pada kedua isolat berhasil diamplifikasi dan dikloning. Hasil sekuensing gen bglS parsial dari kedua isolat potensial teridentifikasi sebagai endo-β-1,3-glukanase dari kelompok glycoside hydrolase (GH) family 16. Model struktur tiga dimensi yang dikonstruksi dari sekuens asam amino bglS parsial memiliki parameter kualitas serta kemiripan yang tinggi dengan model protein eksperimental endo-β-1,3-glukanase parsial dari Nocardiopsis sp. F96., The β-1,3-glucanase enzyme is one of the enzymes capable of hydrolyzing the glucan components of phytopathogenic fungal cell walls. Streptomyces spp. isolated from the maize rhizosphere are suspected to produce enzymes with glucanolytic activity and have the potential to be developed as biological controlling agents against phytopathogenic fungi. This study aims to quantitatively analyze the enzymatic activity of glucanase in two Streptomyces spp. isolates with the highest glucanolytic index from previous research, and to identify their encoding genes. The research methods include quantitative analyze of the glucanase activity, amplification of the endo-β-1,3-glucanase (bglS) gene, cloning, confirmation of cloning results, sequencing, phenetic tree analysis, and protein model prediction. The specific activity enzyme of S. collinus ARJ38 was higher than that of S. tritolerans ARJ32, with a value of 41.599 U/mg on the 8th day of incubation. The presence of the bglS gene in both isolates was successfully amplified and cloned. The sequencing results of the bglS gene from both potential isolates were identified as endo-β-1,3-glucanase from the glycoside hydrolase family 16. The three-dimensional structure model constructed from the partial bglS amino acid sequence exhibited high-quality parameters and high similarity with the experimental protein model of partial endo-β-1,3-glucanase from Nocardiopsis sp. F96.
Keyword: glucanase, phenetic analysis, protein model, rhizosphere actinomycetes, TA cloning, aktinomiset rizosfer, fenetik, glukanase, model protein

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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