Judul: Production of ß-1,3-Glucanase Enzyme from  Streptomyces sp. Antifungal Phytopathogens on Several Mediums and  Determination of its Activity
Abstrak: Enzim ß-1,3-glukanase merupakan enzim hidrolitik yang mampu mendegradasi ß-glukan penyusun dinding sel cendawan fitopatogen. Enzim ini dapat diproduksi Streptomyces tritolerans ARJ 32 dan Streptomyces collinus ARJ 38 dan berpotensi sebagai fungisida alami. Namun, produksi enzim ini membutuhkan media produksi yang relatif mahal. Oleh karena itu, penelitian ini bertujuan memproduksi enzim ß-1,3-glukanase dari S. tritolerans ARJ 32 dan S. colinus ARJ 38 antifungi fitopatogen pada beberapa medium dan menentukan aktivitasnya. Kuantifikasi aktivitas enzim ß-1,3-glukanase menunjukan nilai aktivitas tertinggi kedua Streptomyces sp. yang dikulturkan di media ekstrak ubi jalar, yakni sebesar 32,970 U/mg (S. tritolerans ARJ 32) dan 80,410 U/mg (S. collinus ARJ 38). Nilai aktivitas enzim ß-1,3-glukanase ini menunjukkan bahwa ekstrak ubi jalar berpotensi digunakan sebagai media alternatif produksi enzim ß-1,3-glukanase. Streptomyces sp. memiliki aktivitas antifungi terhadap F. oxysporum dan R. solani dengan penghambatan 23,96% dan 32,52% (ARJ 32) dan 21,88% dan 37,40% (ARJ 38)., ß-1,3-Glucanase enzyme is a hydrolytic enzyme capable of degrading ß-glucan constituting fungi cell wall. This enzyme can be produced by Streptomyces tritolerans ARJ 32 and Streptomyces collinus ARJ 38 and has potential as a natural fungicide. However, the production of this enzyme requires relatively expensive ingredients. Therefore, this study aimed to produce ß-1,3-glucanase enzymes from S. tritolerans ARJ 32 and S. colinus ARJ 38 against phytopathogenic fungi on several media and determining their activity. Quantification of glucanase enzyme activity showed the highest activity of both Streptomyces sp. cultured in sweet potato extract broth media, with 32,970 U/mg (S. tritolerans ARJ 32) and 80,410 U/mg (S. collinus ARJ 38). These results shows that sweet potato extract is potentially an alternative media production for ß-1,3-glucanase enzyme production. Streptomyces sp. had antifungal activity against F. oxysporum and R. solani with inhibition of 23,96% and 32,52% (ARJ 32) and 21,88% and 37,40% (ARJ 38).
Keyword: antifungi, molase, Ubi jalar, enzim ß-1,3-glukanase, kentang

Judul: Enzyme Activity of β-1,3-Glucanase from Streptomyces spp. Rhizosphere and Cloning of its Encoding Gene
Abstrak: Enzim β-1,3-glukanase merupakan salah satu enzim yang mampu menghidrolisis glukan penyusun dinding sel cendawan fitopatogen. Aktinomiset rizosfer jagung dari kelompok Streptomyces spp. diduga mampu memproduksi enzim yang memiliki aktivitas glukanolitik dan berpotensi untuk dikembangkan sebagai agen biokontrol cendawan fitopatogen. Penelitian ini bertujuan menganalisis aktivitas enzim glukanase secara kuantitatif dua isolat Streptomyces spp. dengan indeks glukanolitik tertinggi pada penelitian sebelumnya dan mengidentifikasi gen penyandinya. Metode penelitian yang dilakukan meliputi uji aktivitas glukanase secara kuantitatif, amplifikasi gen endo-β-1,3-glukanase (bglS), kloning, konfirmasi hasil kloning, sekuensing, analisis fenetik, dan prediksi model protein. Aktivitas spesifik enzim isolat S. collinus ARJ38 lebih tinggi dari S. tritolerans ARJ32, yakni sebesar 41,599 U/mg pada waktu inkubasi hari ke-8. Keberadaan gen penyandi bglS pada kedua isolat berhasil diamplifikasi dan dikloning. Hasil sekuensing gen bglS parsial dari kedua isolat potensial teridentifikasi sebagai endo-β-1,3-glukanase dari kelompok glycoside hydrolase (GH) family 16. Model struktur tiga dimensi yang dikonstruksi dari sekuens asam amino bglS parsial memiliki parameter kualitas serta kemiripan yang tinggi dengan model protein eksperimental endo-β-1,3-glukanase parsial dari Nocardiopsis sp. F96., The β-1,3-glucanase enzyme is one of the enzymes capable of hydrolyzing the glucan components of phytopathogenic fungal cell walls. Streptomyces spp. isolated from the maize rhizosphere are suspected to produce enzymes with glucanolytic activity and have the potential to be developed as biological controlling agents against phytopathogenic fungi. This study aims to quantitatively analyze the enzymatic activity of glucanase in two Streptomyces spp. isolates with the highest glucanolytic index from previous research, and to identify their encoding genes. The research methods include quantitative analyze of the glucanase activity, amplification of the endo-β-1,3-glucanase (bglS) gene, cloning, confirmation of cloning results, sequencing, phenetic tree analysis, and protein model prediction. The specific activity enzyme of S. collinus ARJ38 was higher than that of S. tritolerans ARJ32, with a value of 41.599 U/mg on the 8th day of incubation. The presence of the bglS gene in both isolates was successfully amplified and cloned. The sequencing results of the bglS gene from both potential isolates were identified as endo-β-1,3-glucanase from the glycoside hydrolase family 16. The three-dimensional structure model constructed from the partial bglS amino acid sequence exhibited high-quality parameters and high similarity with the experimental protein model of partial endo-β-1,3-glucanase from Nocardiopsis sp. F96.
Keyword: glucanase, phenetic analysis, protein model, rhizosphere actinomycetes, TA cloning, aktinomiset rizosfer, fenetik, glukanase, model protein

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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