Judul: Eksplorasi Spasial Karang Lunak Kaitannya dengan Senyawa Bioaktif Bakteri Simbion.
Abstrak: In ecology, soft and hard corals have the same function in the waters. The distribution of soft corals is strongly influenced by the characteristics of the aquatic environment. Soft corals had been knows contain of bioactive compounds that can be used as a marine natural product, but naturally theses resource are limited and very difficult to cultivated. Therefore, the isolation of bacterial symbiont on soft coral is one of alternatives in an effort to utilize these resources in sustainability. This study had four main objectives that include the following: (1) to determine the differences of the soft corals between sheltered and exposed area in Pongok Island, Soulth of Bangka and Tegal Island in Lampung Bay, Indonesia; (2) to find of the soft corals inhibition potential for antibacterial activity; (3) to measure the antibacterial activity level and minimum inhibitory concentration of bioactive compounds in the soft coral S. flexibilis and S. polydactyla species; (4) to find the isolation of bacterial symbionts from soft coral S. flexibilis and S. polydactyla species that the potential to producted bioactive compound. The results found eigtht types of soft corals classified in four genera (Lobophytum, Nephthea, Sarcophyton and Sinularia) were found in both sites, six species were identified in the waters of South Bangka (at 9 meters depth) and two species (at 3 meters depth). In Tegal Island waters (closed waters), only 2 species from the genus Sinularia were recorded (at 2-5m depth). There were 2 stations at Pongok Island namely, PGK1 and PGK2, while in Tegal Island, there were 4 stations namely TGL1, TGL2, TGL3 dan TGL4. Principal component analyses showed that both waters can be classified based on their physical-chemical characteristic, which were depth, currents, phosphate and turbidity waters. Discriminant function were showed in phosphate variable. While the similarity analysis showed that both waters had very strong similarity of about 79%. In sampling treatment, the biomass among wet and dry samples varied. The highest shrinkage due to drying was found in Nephthea, followed by Lobophytum and Sarcophyton, while the lowest was found in the genus of Sinularia. Extracted from 12 samples of soft coral, the lowest extract weight was found in the semipolar solvent (EtOAc), while the extract weight of n-Hex and MeOH was vary. Inhibition power from all extract samples were found on soft coral extract in the EtOAc and MeOH solvents. The highest value of inhibition power was found in soft coral of Sinularia polydactyla and S. flexibilis within strong catogery. Principal component analysis showed there were corelations between the the environment characteristics with the bioactive compounds inhibition of soft corals, that the identifier parameters include; depth, currents, phosphate and turbidity waters. Discriminant function were showed in depth variable. Extracts weight of both species S. flexibilis (SFTLS4) and S. polydactyla (SPTLS2) found the same relatively, except extract in n-Hexane (n-Hex) solvent from SFTLS4 samples that higher compered to extract weigth in other solvents. vii Antibacterial activites of both spesies showed only on extract in ethyl acetate (EtOAc), within strong category. For purification were obtained eigth fractions (F1-F8) for SFTLS4 extractions and six fractions (F1-F6)
Keyword: antibacterial activity, bacterial symbiont, bioactive compound, sinularia, soft coral

Judul: Eksplorasi Bakteri Simbion Spons di Ekosistem Lamun
Abstrak: Sponge has been acknowledged for its ability to produce secondary metabolites compounds that have been explored for new source of marine natural product compounds. Unfortunately, information on sponge ecological interaction, especially concerning its secondary metabolite production and symbiotic organisms, are usually from observation and experimental researches in coral reefs ecosystem. Meanwhile, not many information has been gathered on sponge community and its ecological interaction in the seagrass ecosystem. Information on sponge community and its ecological interaction in seagrass ecosystem should be explored intensively, for seagrass vegetation could has different environmental condition due to seagrass species characterization that composing the ecosystem. Thus, vegetation characterization of seagrass will influence sponge community and its secondary metabolite, and also its interaction with symbiotic microbial (bacterial). This research wants to figure out several issues concerning sponge community in seagrass ecosystem. These issues are: will sponge species composition and association be different due to condition of seagrass vegetation in the ecosystem; is sponge species in seagrass ecosystem have the same potential concerning its antibacterial activity as in reefs area; how diverse the sponge bacterial symbiont and the potential of its secondary metabolite; and also how the ecological interaction between sponge and its symbiotic bacterial. This research was conducted in several stages. The first stage is field observation at seagrass ecosystem. The next stage was conducted as laboratory activities. Laboratory activities were conducted in several phases. The phase was an assay to test the antibacterial activity of sponges tissues on generally tested bacteria (Escherichia coli and Staphylococcus aureus) and marine bacteria isolates from surrounding water (Al1, Al2, Al3, Al4 and Al5). The aims of this activity were to screen potential sponge that having antibacterial activity, and isolating its symbiotic bacterial. Afterwards, the next phase was an assay to test the antagonistic activity of sponge symbiotic bacterial against marine-biofilm forming bacteria. Symbiotic bacterial with high antagonistic activity then analyzed for its species diversity, using molecular analysis of symbiotic bacterial DNA fingerprinting and identification. Field observation was done in two different seagrass meadow/bed in Pramuka Island, Seribu Islands, near Jakarta Bay, Indonesia, since September 2013 to Mei 2014. Laboratory assays activities were done in Marine Microbiology Laboratory and Marine Biosystematics and Biodiversity, Departement of Marine Science and Technology, Bogor Agricultural University (IPB). Antibacterial assay on sponge tissue was conducted since September 2013 to March 2014, whilst isolation on symbiotic bacterial and secondary metabolites assay were done from December 2013 to November 2015. Molecular analysis on bacterial symbionts diversity and identification were just done ons January to May 2016. Results of this research showed that sponge community in seagrass ecosystem was influenced by the density, morphological form and vegetation architectural of seagrass beds. Sponge will have more species number (higher diversity), with lower abundance in patchy seagrass bed. On the contrary, diversity of sponge will be lower, with higher individual number (abundance) in continuous seagrass bed, regarding higher protection mechanism from predatory activities in continuous bed. Overall, sponge community at both seagrass beds (Site 1 and 2) were dominated by Spirastrella sp. (Sp) and Agelas conifera sponges. Antibacterial assay showed that only
Keyword: asosiasi spons, anti biofilm, bakteri simbion, interaksi ekologis, lamun

Judul: Analysis of M/G/1 Queue Model with Two Phases of Service and Bernoulli Feedback System
Abstrak: Model antrean M/G/1 dengan sistem feedback Bernoulli adalah model antrean dengan proses kedatangan mengikuti proses Poisson. Pada karya ilmiah ini dibahas sistem antrean M/G/1 dengan dua fase layanan. Setelah layanan pertama selesai, pelanggan dapat memilih untuk meninggalkan sistem dengan peluang ... dst, The M/G/1 queueing model with the Bernoulli feedback system is a queueing model with the arrival process following the Poisson process. In this manuscript M/G/1 queueing system with two phases of service is discussed. After the first service is completed, the customer can choose to leave the system with probability ... dst
Keyword: queue, Bernoulli, probability generating function, expected value