Judul: The Potential of Daldinia sp. as Antimicrobial
Abstrak: Cendawan telah banyak dilaporkan sebagai agen biokontrol ataupun penggunaannya dalam bidang medis. Daldinia merupakan genus dari famili Xylariaceae yang dapat mengeluarkan metabolit sekunder, seperti beberapa concentricols dan cytochalasin. Metabolit sekunder ini dapat berfungsi sebagai antibakteri dan anticendawan. Oleh karena itu, penelitian ini bertujuan mengetahui kemampuan Daldinia sebagai antimikroba terhadap Fusarium oxysporum f. sp. cubense (foc) IPBCC 19 1472, Escherichia coli ATCC 8739, dan Staphylococcus aureus ATCC 6538 patogen. Metode yang digunakan yakni terdiri atas pengambilan sampel Daldinia dari sekitar kampus Dramaga IPB, isolasi sampel, pengamatan morfologi sampel hasil isolasi, uji antagonis Daldinia terhadap mikroba patogen melalui dual culture. Semua galur Daldinia sp. dapat menghambat cendawan patogen foc IPBCC 19 1472, yaitu melalui mekanisme kompetisi ruang. Namun semua galur Daldinia tidak mampu menghambat bakteri patogen Escherichia coli ATCC 8739 dan Staphylococcus aureus ATCC 6538. Foc IPBCC 19 1472 dapat dihambat hingga 54,4 ± 5,1% oleh Daldinia sp. 3 dan paling rendah sebesar 37,3 ± 7,7% oleh Daldinia sp. 1., Daldinia is a genus from the Xylariaceae family that can produce secondary metabolites, such as some concentricols and cytochalasins. These secondary metabolites can function as antibacterial and antifungal agents. Therefore, this study aimed to determine the ability of Daldinia as an antimicrobial against pathogens Fusarium oxysporum f. sp. cubense (foc) IPBCC 19 1472, Escherichia coli ATCC 8739, and Staphylococcus aureus ATCC 6538. The method consisted of taking Daldinia samples from around the Darmaga IPB campus, sample isolation, morphological observations of isolated samples, and antagonistic study of all Daldinia sp. strains against pathogenic microbes through dual culture. All Daldinia sp. strains can inhibit the pathogenic fungus foc IPBCC 19 1472 through space competition. However, all Daldinia sp. strains could not inhibit pathogenic bacteria Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538. Foc IPBCC 19 1472 can be inhibited up to 54.4 ± 5.1% by Daldinia sp. 3, and the lowest was 37,3 ± 7,7% by Daldinia sp. 1.
Keyword: Dual culture, Escherichia coli, foc, Staphylococcus aureus, uji antagonis

Judul: In Vitro Antagonistic Assay of Endophytic Fungi Isolated from Pilea microphylla (L.) Liebm against Fusarium oxysporum f. sp. cubense (Foc)
Abstrak: ISHMAH AFIAH. In Vitro Antagonistic Assay of Endophytic Fungi Isolated from Pilea microphylla (L.) Liebm against Fusarium oxysporum f. sp. cubense (Foc). Supervised by SRI LISTIYOWATI and TRIADIATI. Endophytic fungi are reported capable of effectively inhibit the growth of plant pathogenic fungi. Utilization of endophytic fungi as an environmentally friendly biological control agent still needs to be done. This study aimed to test the in vitro antagonism ability of the endophytic fungi from Pilea microphylla (L.) Liebm against the pathogenic fungi Fusarium oxysporum f. sp. cubense (Foc) and analyzed the types of interactions and their inhibitory mechanisms. Antagonism test was performed by pairing the endophytic fungi and Foc using dual culture methods. The control was made without the addition of endophytic fungi as the antagonisms. Analysis of percentage inhibition (DH) and growth rate of radial mycelia Foc was performed using a completely randomized design (CRD). The results showed that the isolate PM 1A2.4 has a moderate inhibitory ability (DH 41.58%), with slight inhibition type of interaction exhibited and probably perform antibiosis mechanism. The isolate PM 2A2.3 has a very weak inhibitory ability (DH 10.76%), indicated by the Foc mycelia grew through (overgrowing) the mycelia of endophytic fungi. Similarly, with the isolate PM 2A2.4 against the Foc (DH 19.68%), the Foc mycelia grew around part of the mycelia of endophytic fungi. The interaction of the two endophytic fungi against Foc was competitive. The Foc hyphae paired with the isolate PM 1A2.4 and PM 2A2.3 showed vacuolization, whereas with the isolate PM 2A2.4 there was no difference with control. The endophytic fungi of P. microphylla had various antagonistic activity against Foc. Keywords: antibiosis, competition, dual culture, inhibition, vacuolization, Cendawan endofit dilaporkan mampu menghambat pertumbuhan cendawan patogen tanaman secara efektif. Pemanfaatan cendawan endofit sebagai agen pengendalian hayati yang ramah lingkungan di bidang pertanian masih perlu dilakukan. Penelitian ini bertujuan menguji kemampuan antagonisme cendawan endofit asal tumbuhan Pilea microphylla (L.) Liebm terhadap cendawan patogen Fusarium oxysporum f. sp. cubense (Foc) secara in vitro dan menganalisis tipe interaksi serta mekanisme penghambatannya. Uji antagonisme dilakukan dengan memasangkan cendawan endofit dan Foc menggunakan metode kultur ganda. Kontrol dibuat tanpa penambahan cendawan endofit sebagai antagonisnya. Analisis persentase daya hambat (DH) dan rata-rata pertumbuhan miselia radial Foc dilakukan menggunakan rancangan acak lengkap (RAL). Hasil penelitian menunjukkan isolat PM 1A2.4 memiliki kemampuan hambat sedang (DH 41,58%), dengan tipe interaksi slight inhibition yang diduga melalui mekanisme antibiosis. Isolat PM 2A2.3 memiliki kemampuan hambat sangat lemah (DH 10,76%), sehingga tampak miselium Foc tumbuh melewati (overgrowing) miselium cendawan endofit. Demikian juga isolat PM 2A2.4 terhadap Foc (DH 19,68%), miselium Foc tumbuh mengelilingi (growth around) sebagian sisi miselium cendawan endofit. Interaksi kedua cendawan endofit tersebut terhadap Foc bersifat kompetisi. Hifa Foc yang dipasangkan dengan isolat PM 1A2.4 dan PM 2A2.3 mengalami vakuolisasi, sedangkan isolat PM 2A2.4 tidak ada perbedaan dengan kontrol. Cendawan endofit asal tumbuhan P. microphylla memiliki kemampuan antagonisme yang bervariasi terhadap Foc. Kata kunci: antibiosis, daya hambat, kompetisi, kultur ganda, vakuolisasi, Endophytic fungi are reported capable of effectively inhibit the growth of plant pathogenic fungi. Utilization of endophytic fungi as an environmentally friendly biological
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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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