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 Jati Belanda (Guazuma ulmifolia) serta Penapisan Potensi Antibakterinya
Abstrak: Endophytic fungi are microorganisms living in healthy tissue of their host plants without causing disease. Endophytic fungi live in every plant, including jati belanda medicinal plant intracellulary and/or intercellulary. Jati belanda (Guazuma ulmifolia) is one of Indonesia medicinal plants. The plant produced antimicrobe substances, including antibacteria. This research aimed to identify three endophytic fungi isolated from jati belanda morphologically and molecularly, and to screen their antibacterial potency by using mycelial extracts obtained with methanol solvent against microflora Escherichia coli, Enteropathogenic Escherichia coli (EPEC) K1-1, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis as tested bacteria. The three endophytic fungi were JBba3, JBba4, and JBa5. Based on morphological characteristics, fungal isolate JBba3 identified as Rhizopycnis sp.1, JBa5 was Rhizopycnis sp.2, whereas JBba4 was Colletotrichum sp. Identification results by using ITS rDNA region showed that isolates JBba3 and JBa5 were Rhizopycnis vagum, meanwhile isolate JBba4 was Colletotrichum sp. All three isolates tested did not inhibit the growth of the microflora E. coli. Isolates Rhizopycnis sp.1 and Rhizopycnis sp.2 did not inhibit the growth of all bacteria tested. Isolate Colletotrichum sp. inhibited the growth of EPEC K1-1 and P. aeruginosa with diameters zone of inhibition were 13.0 and 6.7 mm, respectively. Antibacterial potencies of Colletotrichum sp. mycelial extract were similar with cefotaxime antibiotic as positive control on two concentrations tested, which were 8 and 64 μg/ml.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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