Judul: Regenerasi talus Kappaphycus alvarezii (Doty) transgenik sitrat sintase (PaCS) secara in vitro
Abstrak: Seaweed is one of Indonesian aquaculture commodities. One type of seaweed that widely produced in Indonesia is Kappaphycus alvarezii (Doty). The amount of national and international market demand of seaweed encourage people to cultivate extensively regardless of environmental factors. Citric acid secretion in plants plays an important role in stress tolerance to heavy metals, especially aluminum. Citrate syntase encoding genes (PaCS) has been successfully introduced into K.alvarezii. This research aimed to compare in vitro regeneration of transgenic citrate synthase (PaCS) K.alvarezii thallus with non-transgenic K.alvarezii thallus and to determine the effect of growth regulators addition in solid culture media. Regeneration parameters such as wet weight gain and the length of the thallus was measured every two weeks for ten weeks. The measurement results were analyzed using t-test analysis. Based on t-test analysis result, there was no significant difference in vitro regeneration of transgenic citrate synthase gene (PaCS) K.alvarezii thallus with non-transgenic K.alvarezii thallus. The results of t-test analysis also showed no significant difference in vitro regeneration of transgenic K.alvarezii thallus cultured on solid PES media before to liquid medium. In addition, provision of ZPT on solid PES culture media did not have a significant effect on transgenic thallus in vitro regeneration.
Keyword: Bogor Agricultural University (IPB), t-test analysis., thallus regeneration, PaCS, Kappaphycus alvarezii

Judul: Introduction of PaCS gene encoding Citrat Synthase to Kappaphycus alvarezii using Agrobacterium tumefaciens
Abstrak: Ice-ice is a disease that reduces the quality of seaweed. This disease is mainly caused by environmental stress rather than pathogen. This is supported by the fact that ice-ice disease is prevalent in the environment where the water have low quality, poor circulation, low salinity and changement of temperature, and high content of heavy metals. Citric acid is known to be a strong chelating agent for aluminum. Citric acid has a very important role in the Kreb cycle. The enzyme involved in the synthesis of citric acid is citrate synthase. Citrate synthase genes from Pseudomonas aeruginosa (PaCS) has been successfully introduced into genome of tobacco (Nicotiana tabacum) and Jatropha curcas using Agrobacterium tumefaciens. Tobacco transgenic plants containing PaCS gene are more tolerant to Al stress compared to non-transgenic plants. This research aims to introduce the citrate synthase gene into genome of seaweed Kappaphycus alvarezii by using Agrobacterium tumefaciens. Cutting Thallus of 0,5 cm were used as explants. Explants were inoculated by Agrobacterium tumefaciens for 15 minutes and then co-cultivated in PES media containing 0,3% agar for 3 days in the dark. The selection of putative transgenic K. alvarezii was carried out in PES agar selective medium containing 10 mg/l hygromicin. Based on hygromicin resistant explant on hygromicin selective medium, the transformation efficiency in K. alvarezii was 7.5 %. The efficiency of shoot regeneration of putative transgenic was 100%, and same as the regeneration efficiency of non transgenic ones. Molecular analysis by PCR showed that one of five putative transgenic K. alvarezii was confirmed as transgenic thallus containing PaCS transgene under the control of 35S CaMV promoter.
Keyword: Kappaphycus alvarezii, seaweed, PaCS gene, Agrobacterium tumefaciens, transformation

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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