Judul: Kloning dan Karakterisasi Gen Penyandi α-amilase (amyA) Aspergillus niger serta Konstruksi Ekspresi dengan Teknologi Gateway
Abstrak: Cloning of the a-amylase gene of Aspergillus niger chromosomal DNA on pDEST 24 plasmid to increase the enzyme activity has been investigated. The transformation was conducted with several steps, including isolation of the messenger RNA, ligation by T4-DNA ligase, transformation of the recombinant DNA, and selection of the transformants using PCR colony. Gene encoding α- amylase isolated using RT-PCR (Reverse Transcriptase Polymerase Chain Reaction technique) and inserted into the pGEM-T Easy vector. Electrophoresis of the PCR products showed that the gene has a size of approximately 1650 bp. BLAST analysis of the DNA sekuen showed that this gene is homologous with the gene encoding α-amylase accessible from the gene bank. Expression of the gene encoding α-amylase of Aspergillus niger used gateway cloning technology. It showed that this gene has been successfully cloned in the cells of Escherichia coli through destination vector (pDEST 24). Electrophoresis of the PCR colony showed that the gene has a size of approximately 1650 bp.
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Judul: Isolasi dan Karakterisasi Gen Penyandi Endo-1,4-β-glukanase dari Kapang Aspergillus fumigatus dan Aspergillus niger
Abstrak: Agricultural waste biomass containing cellulose is the raw material for bioethanol production and is the cheapest and most abundant in nature. It can be hydrolyzed with the help of cellulase enzymes produced by fungus A. fumigatus and A. niger. These enzymes consist of three main activities, namely endo-1,4-β- glucanase, exo-1,4-β-glucanase, and β-glucosidase. The main purpose of this research is isolation and characterization of genes encoding endo-1,4-β-glucanase from A. fumigatus and A. niger. The hypothesis is the gene encoding endoglucanase can be isolated using specific primers designed based on gene sequences accessible from the gene bank. Genes encoding endoglucanase isolated using RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) techniques and inserted into the vector pGEM-T Easy. Endoglucanase activity measurements carried out on pellets and supernatant of the recombinant cells by DNS (dinitrosalicylic acid) method. Electrophoresis of the PCR products showed that the gene has a size of approximately 1300 bp. BLAST analysis of the DNA sekuen showed that these genes are homologous with genes encoding endoglucanase accessible from the gene bank. Expression test of the genes encoding endoglucanase of A. niger showed that this gene has been successfully expressed in the cells of Escherichia coli through pYES2/CT vector. The highest activity of endoglucanase was found in the supernatant of the recombinant cells carrying vector pYES2/CT (8.8309 U/mg).
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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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