Judul: Dental Antibiofilm Potential of Ruku-Ruku Plant by In Silico Study of Glucosyltransferase Enzyme Inhibition
Abstrak: Biofilm gigi terbentuk akibat infeksi Streptococcus mutans yang memfermentasi karbohidrat menjadi asam. Bakteri tersebut memproduksi glukosiltransferase yang berperan dalam sintesis glukan enamel. Tanaman ruku-ruku memiliki senyawa aktif yang berpotensi sebagai antibiofilm. Penelitian ini bertujuan menguji potensi inhibisi senyawa aktif tanaman ruku-ruku terhadap glukosiltransferase serta menganalisis interaksinya. Penelitian dilakukan dengan metode penapisan virtual dan penambatan molekuler menggunakan perangkat lunak YASARA Structure. Hasil penelitian menunjukkan dari 40 senyawa aktif tanaman ruku-ruku, terdapat enam senyawa terbaik yang mampu menginhibisi glukosiltransferase serta memiliki interaksi dengan tiga residu penting pada enzim, yaitu Asn481, Glu515, dan Trp517. Senyawa tersebut adalah asam ursolat, asam olenolat, apigenin-7-glukuronida, orientin, isoorientin, dan isoviteksin yang memiliki konstanta disosiasi lebih rendah dibandingkan ligan alami dengan rentang 0.048 hingga 0.398 µM dan memiliki nilai energi bebas ikatan lebih negatif dari ligan alami dengan rentang -9979 hingga -8730 kal/mol., Dental biofilm is formed due to infection of Streptococcus mutans, which is able to ferment carbohydrates into acid. These bacteria produce glucosyltransferase which plays role in synthesizing glucan enamel. Ruku-ruku plant have active compounds that have potential as antibiofilm. This study aimed to examine the inhibition potential of active compounds from ruku-ruku plant against the glucosyltransferase and to analyze its interaction. The research was conducted using virtual screening molecular and docking methods with YASARA Structure software. The results showed that of 40 active compounds from ruku-ruku plant, there were six best compounds that could inhibit glucosyltransferase and interact with three important residues, namely Asn481, Glu515, and Trp517. These compounds are ursolic acid, oleanolic acid, apigenin-7-glucuronide, orientin, isoorientin, and isovitexin which have lower dissociation constants than natural ligands in range of 0.048 to 0.398 µM and have more negative free energy of binding values with range of -9979 to -8730 cal/mol.
Keyword: biofilm, glucosyltransferase, molecular docking, ruku-ruku, S. mutans

Judul: Potensi ekstrak residu distilasi uap daun Zingiberaceae sebagai antibakteri Streptococcus mutans dan degradator biofilm pada gigi
Abstrak: Tanaman Zingiberaceae biasa digunakan untuk mengobati berbagai penyakit dan sebagai bumbu masakan. Genus yang umum digunakan sebagai obat tradisional ialah Curcuma dan Zingiber. Keduanya berpotensi sebagai antibakteri dan diduga mampu mendegradasi biofilm Streptococcus mutans. Penelitian ini bertujuan menentukan potensi residu distilasi daun Zingiberaceae sebagai antibakteri terhadap S.mutans dan degradator biofilm pada gigi. Daun yang digunakan hasil dari residu distilasi dan diekstraksi dengan sokletasi dan dilanjutkan dengan ekstraksi menggunakan 3 pelarut berbeda (n-heksana, etil asetat, dan metanol). Uji antibakteri dan degradasi biofilm dilakukan menggunakan teknik mikrodilusi dengan pelat 96-sumur steril. Ekstrak metanol temu putih memiliki aktivitas terbaik dengan nilai konsentrasi hambat minimum dan konsentrasi bunuh minimum sebesar 15.6 μg/mL dan aktivitas degradasi biofilm yang baik dengan IC50 15.3 μg/mL. Pada Kromatografi Lapis Tipis bioautografi terdapat 4 spot dan spot yang paling aktif pada Rf 0.90. Terpenoid diduga sebagai senyawa aktif antibakteri dan degradator biofilm.
Keyword: antibacterial, biofilm degradator, Streptococcus mutans, Zingiberaceae

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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