Judul: Karakteristik fisik siklon tropis di samudera hindia bagian selatan dan pengaruhnya terhadap curah hujan di Jawa, Bali dan Nusa Tenggara
Abstrak: Secara meteorologis, siklon tropis adalah sebuah tekanan rendah yang terbentuk secara umum di daerah tropis yang memiliki lintang rendah antara 10 derajat dan 20 derajat LU/LS dari ekuator. Siklon tropis merupakan bagian penting dari sistem sirkulasi atmosfer yang berperan dalam perpindahan panas dari daerah katulistiwa menuju daerah lintang lebih tinggi. Penelitian ini bertujuan untuk menganalisis karakteristik fisik siklon tropis di Samudera Hindia bagian selatan dan pengaruh siklon tersebut terhadap curah hujan di Jawa, Bali dan Nusa Tenggara.
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Judul: Siklon tropis graham dan akibat fisik di Teluk Pelabuhan Ratu
Abstrak: Penelitian dan penulisan hasil penelitian ini dilakukan selama satu tahun, dimulai April 1992 sampai Maret 1993. Lokasi penelitian adalah Samudera India bagian Baratdaya Sumatera sampai bagian Selatan Jawa (4°- 16°LS;920-104°BT) serta perairan Teluk Pelabuhan Ratu (6°57′-7°30′LS; 106°22′-106°33′BT). Data pola awan diambil dari BMG, berupa citra-citra satelit cuaca hasil deteksi satelit cuaca GMS pada kanal inframerah. Pengambilan data pola awan didasarkan pada waktu tumbuhnya depresi tropis di Samudera India bagian Baratdaya Sumatera, perkembangannya menjadi siklon tropis Graham, sampai hilangnya gangguan siklon ini di Samudera India bagian Selatan Jawa. ..
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Judul: Heterologous Expression Of Endo-Β-Xylanase From Bacillus Pumilus Strain Bcrs-01 In Escherichia Coli.
Abstrak: Xylanases are glycoside hydrolase family 11 which depolymerise xylan in the plant cell wall, the most excessive form of hemicellulose. Endo-β-xylanases (EC 3.2.1.8) are most important to breakdown β-1,4-glicoside bond of xylan to produce disaccaride xyloolygosaccaride (XOs) and xylose (monomer). Bovine rumen fluids have potential to obtain endo-β-xylanase produced of bacteria. The objectives of this study were to obtain xylanase producing bacteria and to express xynA gene encoding endo-β-xylanase from bacterium in Escherichia coli. Twenty nine isolate bacteria have been succesfully isolated from bovine rumen fluid in agar medium containing birchwood xylan. Isolate BCRS-01 bacterium was previously screened for the high production of xylanase. Based on 16S rRNA gene sequence analysis, BCRS-01 showed high similarity (99%) to Bacillus pumilus (accession number NR043241). The crude xylanase had optimal activity at 55oC, pH 7.0. Furthermore, the crude xylanase exhibited broad pH stability from 4.0 to 10.0 and remained more than 60% and 40% of its activity after incubation at pH 4.0 until 10.0, respectively for 60 min. It also showed a stability at temperature 25-50oC since it retained 80% and 50% of its activity when incubated at 50oC or 30 and 60 min, respectively. The xylanase activity was strongly inhibited by Ca2+ and Cu2+ at concentration 10 mM, and as little as 1 mM for Mn2+. Therefore, this xylanase has potentially used as additive feeds in animal feed industry. The DNA sequence xynA gene encoded endo-β-xylanase was amplified and cloned into the expression vector pET-15by under the control of T7 promoter. The recombinant protein had succesfully expressed in Escherichia coli BL21 (DE3) pLysS. A protein recombinant of approximately, 26.7 kDa was observed on the SDS-PAGE analysis. Crude extract of recombinant endo-β-xylanase demonstrated activity of enzyme at 56 U mL-1 using birchwood xylan as a substrate at 55oC for 10 min.
Keyword: Bacillus pumilus, bovine rumen fluid, endo-β-xylanase, heterologous expression.