Judul: Identifikasi Cendawan Endofit Asal Tanaman Obat Jati Belanda (Guazuma ulmifolia) serta Penapisan Potensi Antibakterinya
Abstrak: Cendawan endofit ialah mikroorganisme yang hidup di dalam jaringan sehat tanaman inangnya tanpa menyebabkan penyakit. Cendawan endofit tumbuh pada setiap tumbuhan, termasuk tanaman obat jati belanda secara intraseluler dan/atau interseluler. Jati belanda merupakan salah satu tanaman obat di Indonesia yang mengandung senyawa antimikroba, termasuk antibakteri. Penelitian ini bertujuan untuk mengidentifikasi tiga cendawan endofit asal jati belanda secara morfologi dan molekuler, serta menapis potensi antibakterinya menggunakan ekstrak miselia dengan pelarut metanol terhadap bakteri uji Escherichia coli flora normal, Escherichia coli Enteropatogenik (EPEC) K1-1, Staphylococcus aureus, Pseudomonas aeruginosa, dan Bacillus subtilis. Ketiga cendawan endofit tersebut ialah JBba3, JBba4, dan JBa5. Berdasarkan karakteristik morfologi, isolat JBba3 teridentifikasi sebagai Rhizopycnis sp.1, JBa5 ialah Rhizopycnis sp.2, sedangkan isolat JBba4 ialah Colletotrichum sp. Hasil identifikasi menggunakan ruas ITS rDNA menunjukkan bahwa isolat JBba3 dan JBa5 ialah Rhizopycnis vagum, sedangkan isolat JBba4 ialah Colletotrichum sp. Semua isolat tidak menghambat pertumbuhan E. coli flora normal. Isolat Rhizopycnis sp.1 dan Rhizopycnis sp.2 tidak menghambat pertumbuhan semua bakteri uji. Isolat Colletotrichum sp. menghambat pertumbuhan bakteri EPEC K1-1 dan P. aeruginosa dengan rata-rata diameter zona hambat masing-masing sebesar 13.0 dan 6.7 mm. Kemampuan antibakteri dari ekstrak miselia dengan pelaut metanol isolat Colletotrichum sp. sama dengan antibiotik cefotaxime sebagai kontrol positif pada dua konsentrasi yang diuji, yaitu 8 dan 64 μg/ml.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB

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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