Judul: Identifikasi senyawa kimia antifungal dari bakteri endofit asal Taxus sumatrana
Abstrak: In recent decades, there has been an increase in fungal infection caused by resistance of some species of fungus to fungicides used in medicinal treatment. The use of antifungal in the treatment of fungal infections should considering the toxicity, efficacy, cost and frequent use had led to emergence of resistant strains. One approach to developing antifungal drugs is use of plants as sources of medicine (Abad et al. 2007). Plants are host for the presence of endophytic microbes. Some of these endophytes produce bioactive compound that are involved in the host-microbes relationship. Taxus is one of the hosts plant for endophytic microbes. An endophytic fungus Paecilomyces sp. was isolated from Taxus mairei, produce metabolites brefeldin A, which has several activities such as antifungal, antiviral and anticancer drugs (Wang et al. 2002). Tayung et al (2007) also reported that a bacterium Pseudomonas fluorescens was isolated from Taxus batacca rhizosphere, produce antimicrobial compounds. Many endophytic microbes associated with Taxus have been demonstrated to produce biactive compound that was an opportunity to explore endophytic microbes of Taxus from Indonesia. Taxus sumatrana was known as the Sumatran Yew that was a needle tree, grown naturally in Indonesia. T. sumatrana was recognized for producing a number of active compounds such as taxol, cephalomannine, 7-epi-10-deacetyltaxol, 7-epi-10- deacetylcephalomannine, baccatin III, 19-hydroxybaccatin III and 10-deacetyl-13- oxobaccatin III taxol, cepalomanin, 7-epi-10-deasetil. Shen et al. (2003) reported, two new taxane diterpenoid, tasumatrol A and B, have been isolated from extract of the leaves and twigs of Taiwanese T. sumatrana. However, the potential of endophytic microbes especially endophytic bacteria from T. sumatrana for producing antifungal compounds is still limited. The aim of this studies were to identify antifungal compound against Candida albicans which produced by endophytes bacteria of T. sumatrana and characterize the selected isolates. The results of this study were expected to receive pharmacological compound which have high value and increase scientific information of antifungal compound from endophytic bacteria of T. sumatrana. Endophytic bacteria were isolated from the stems and leaves of T. sumatrana (Tomita 2003). Selection of isolates was done by paper disk diffusion and point inoculation method. Sixteen isolates were found at isolation of endophytic bacteria. Among 16 isolates, isolate Tx 4 showed antagonistic activity against C. albicans. The culture broth of Tx 4 isolate was centifuged and supernatant was extracted using n-hexane solvent three times. Extracts which have antifungal activity was analyzed by Thin Layer Chromatography using n-hexane: ethyl acetate solvent. Extracts was fractionated by column chromatography using nhexane: ethyl acetate solvent as a gradient. Fractions were obtained, tested antagonistic to C. albicans. Fractions which have antifungal activity were analyzed by preparative TLC. Fractions which showing antifungal activity, were analyzed by Infra Red Spectrophotometry (IR) and Gas Chromatography - Mass Spectrometry (GC-MS). The IR results were wavenumber 1740.64 cm-1 (carbonyl group), 2919.06 cm-1 (aromatic group), 1521.73 cm-1 (alkene group) and 1081,03 cm-1 (carboxyl group). Identification by GC-MS estimated that bioactive compounds contain of 1,2-benzenedicarboxylic acid, diisooctyl ester. Identification of Tx 4 isolate was done base on morphology and molecular. The results of morphology identification showed that Tx 4 isolate
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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: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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