Judul: Potensi Senyawa Antiparasit dari Bakteri Simbion Spons Spirastrella hartmani di Pulau Pramuka Kepulauan Seribu Jakarta
Abstrak: Spons dan simbion bakteri di dalam tubuhnya memiliki senyawa bioaktif yang banyak dan bermanfaat untuk farmakologi, seperti sitotoksik, anti-HIV, antitumor, antikanker, antivirus, antibakteri, antijamur, dan antiparasit. Penelitian ini bertujuan untuk mengetahui adanya potensi antiparasit yang terdapat pada isolat bakteri simbion spons Spirastrella hartmani. Rancangan penelitian yang digunakan yaitu rancangan acak faktorial, 5 isolat terbaik (S121a, S121b, S122a, S122b dan S122c) dipilih dari 44 isolat bakteri simbion Spirastrella hartmani di Pulau Pramuka. Uji antiparasit dilakukan secara in vitro terhadap Ascaridia galli, konsentrasi yang digunakan pada masing-masing ekstrak isolat adalah 0.7 gram/ml, kemudian pirantel pamoat® dan etanol digunakan sebagai kontrol positif dan kontrol negatif. Data yang diperoleh dianalisis dengan ANOVA dan uji Duncan. Hasil penelitian menunjukkan bahwa masing-masing isolat memiliki aktivitas antiparasit yang berbeda nyata, dan ekstrak S122c menunjukkan aktivitas antiparasit yang lebih baik dibandingkan yang lainnya., Sponges and their bacterial symbionts have many bioactive compounds fuctional to pharmacological purposes, such as cytotoxic, anti-HIV, antitumor, anticancer, antiviral, antibacterial, antifungal, and antiparasitic. The objective of this study was to investigate the potency of antiparasite compounds isolated from bacterial symbiont of Spirastrella hartmani sponges. Utilizing randomized factorial design 5 isolates were selected, that is S121a, S121b, S122a, S122b and S122c, from 44 bacterial isolates Spirastrella hartmani in Pramuka Island. In vitro antiparasitic assay was applied against Ascaridia galli, using extracted antiparasitic compound with concentration of 0.7 gram/ml, while pyrantel pamoat® and ethanol were applied as positive and negative control. The data were analyzed by ANOVA and Duncan’s test. Results of this study showed that each antiparasitic compound has different antiparasitic activity, and antiparasitic compound S122c was the most effective compare to others.
Keyword: antiparasit, bakteri simbion, Spirastrella hartmani, spons

Judul: Potensi Isolat Bakteri Simbion Spons Agelas conifera di Ekosistem Lamun Pulau Pramuka, Kepulauan Seribu, Jakarta
Abstrak: Pulau Pramuka merupakan pulau dengan banyak ekosistem, salah satunya adalah ekosistem lamun. Ekosistem lamun memiliki peranan sebagai habitat oleh banyak biota, salah satunya adalah spons. Spons Agelas conifera adalah jenis spons yang paling dominan ditemukan di Pulau Pramuka, Kepulauan Seribu. Kemampuan spons untuk memproduksi senyawa metabolit sekunder sangat dipengaruhi oleh kondisi habitat spons. Tingginya tingkat kesuburan ekosistem lamun dapat mempengaruhi produksi metabolit sekunder spons. Penelitian ini bertujuan mengisolasi dan menguji potensi bakteri simbion spons serta mengetahui jenis lamun yang berasosiasi dengan Agelas conifera. Isolasi bakteri simbion spons dilakukan mengunakan media Zobell 2216 ½ strength. Uji yang dilakukan adalah antibakteri, antifungi, selulase, kitinase, resistensi sinar UV, toleransi suhu, serta pengukuran kualitas perairan dan kualitas sedimen. Jenis lamun yang ditemukan pada lokasi pengamatan yaitu, Thalassia hemprichii, Cymodocea rotundata, Halophila ovalis, dan Enhalus acoroides. Thalassia hemprichii mendominasi di kedua Stasiun penelitian. Sebanyak 61 individu spons Agelas conifera ditemukan pada penelitian ini. Spons Agelas conifera lebih banyak ditemukan pada kerapatan dan tutupan lamun yang tinggi, yaitu jenis Thalassia hemprichii. Isolat bakteri ditemukan sebanyak 45 isolat yang bersimbiosis dengan spons. Jumlah spons yang ditemukan dikaitkan dengan persentase tutupan lamun perjenis dengan menggunakan analisis koresponden yang menunjukkan spons lebih banyak ditemukan pada tutupan lamun T.hemprichii. Potensi bakteri simbion yang ditemukan bervariasi seperti resisten terhadap sinar ultraviolet (UV) dan rentang toleransi suhu yang lebar. Hasil yang berbeda nyata antara potensi pada kedua stasiun ditunjukkan oleh uji ANOVA single factor dengan p<0.05. Dibutuhkan pengujian lebih lanjut untuk melihat potensi lebih dalam dari bakteri simbion spons Agelas conifera di ekosistem lamun Pulau Pramuka Kepulauan Seribu., Pramuka Island is an island with many ecosystems, one of which is a seagrass ecosystem. The seagrass ecosystem has a role as a habitat for many biota, one of which is a sponge. Agelas conifera sponge is the most dominant sponge found in Pramuka Island, Kepulauan Seribu. The ability of sponges to produce secondary metabolites is greatly influenced by the conditions of the sponge's habitat. The high fertility rate of the seagrass ecosystem can affect the production of secondary metabolites of the sponge. This study aims to isolate and test the potential of sponge symbiont bacteria and to determine the types of seagrass associated with Agelas conifera. Spongy symbiont bacteria was isolated using Zobell 2216 ½ strength media. The tests carried out were antibacterial, anti-fungal, cellulase, chitinase, UV resistance, temperature tolerance, and measurement of water quality and sediment quality. The types of seagrass found at the observation site were Thalassia hemprichii, Cymodocea rotundata, Halophila ovalis, and Enhalus acoroides. Thalassia hemprichii dominates at both research stations. A total of 61 individual Agelas conifera sponges were found in this study. Agelas conifera sponges are more commonly found in high density and cover of seagrass, namely Thalassia hemprichii. As many as 45 isolates were found in symbiosis with a sponge. The number of sponges found was associated with the percentage of seagrass cover per type using a correspondent analysis which showed that sponges were more common in T.hemprichii seagrass cover. The potential of symbiont bacteria found varied such as resistance to ultraviolet (UV) rays and a wide temperature tolerance
Keyword: Agelas conifera, Pramuka Island, Seagrass habitat, Symbiotic bacteria

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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