Judul: Isolasi dan identifikasi senyawa bioaktif herbisida dari bioproduksi endofit eurycoma longifolia jack
Abstrak: Mikroba endofitik merupakan mikroorganisme yang hidup dalam jaringan tanaman yang mempunyai aktivitas yang sama dengan tanaman inangnya. Mikroba endofit dipertimbangkan untuk menjadi sumber penghasil metabolit sekunder yang berpotensi sebagai obat-obatan, senyawa aktif untuk pertanian, dan atau untuk eksploitasi industri. Fungsi ini metabolit adalah untuk mencegah atau melawan perusak/pemangsa baik berupa hama/penyakit, penyerbukan, allelopatik, pembusukan dan perlindungan terhadap sinar UV. Pada penelitian ini kami menggunakan mikroba endofit yang diperoleh dari tanaman Pasak Bumi, Eurycoma longifolid Jack. Tanaman E. longifolia Jack merupakan tanaman yang memiliki berbagai aktivitas seperti antimalaria, antifeedant, insektisida dan herbisida.
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Judul: Identifikasi Cendawan Endofit Asal Tanaman Obat dan Penapisan Potensinya sebagai Antibakteri
Abstrak: Endophytic fungi are microorganisms living in plant tissue without causing any harm to its host. The fungi can be found in all plants including medicinal plants. Endophytic fungi produced variety of bioactive compounds such as antibacterial substances. This research aimed to identify 3 isolates of endophytic fungi JBa8, JMa3, and SLbt3 which were isolated from medicinal plants and to screen their potency as source of antibacterial compounds. Identification of endophytic fungi was performed based on morphological characteristics and DNA barcode using ITS region. Antibacterial test was conducted against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Enteropathogenic Escherichia coli (EPEC) K1-1, and microflora E. coli by antagonism technique and agar diffusion method using mycelia extract with methanol solvent. The inhibition activity of fungal extract on bacterial tested was observed on the day 3rd, 7th, 10th, and 14th after incubation by measuring clear zone around the colonies. The 3 isolates were tentatively identified as Fusarium solani for JBa8, Fusarium sp. for JMa3, and Colletotrichum sp. for SLbt3. Antibacterial activities were observed in F. solani and Fusarium sp. which were isolated from jati belanda (Guazuma ulmifolia) and jahe merah (Zingiber officinale), respectively. F. solani inhibited the growth of EPEC K1-1, whereas Fusarium sp. suppressed P. aeruginosa with clear zone produced was 12 mm. Fusarium sp. had antibacterial activity similar with that of 8 μg/mL cefotaxime positive control. The F. solani antibacterial activity, however, was lower than the two positive control concentrations used. Colletotrichum sp. isolated from sambiloto (Andrographis paniculata) did not have any antibacterial to all bacteria tested.
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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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