Judul: Respon Pertumbuhan Tiga Jenis Semai pada Tanah Padat
Abstrak: The research was conducted to examine the seedling of meranti bapa (Shorea selanica), trembesi (Samanea saman) and sengon buto (Enterolobium cyclocarpum) the growth response at the different level of bulk density (0.9, 1.0, 1.1, 1.2, 1.3 g/cm3) with 5 replications. Soil was compacted with a proctor test, then 3 types seedling have germinated grown on solid media was observed for the growth reponse. After 6 month growth three types seedling growth reponse was measured. The result showed that the height, diameter, root penetration and root shoot ratio linearly decrease with the increase of bulk density. The root penetration of seedling of trembesi (Samanea saman) could not penetrate deeply at the hardest soil (1.1 g/cm3), while meranti bapa (Shorea selanica) and sengon buto (Enterolobium cyclocarpum) at the hardest soil (1.3 g/cm3). Roots are getting shorter with the increase of bulk density, so that the roots needs space to grow. The bulk density 1.1 and 1.2 g/cm3 was highly influential reduces root growth response. So it can be concluded that the bulk density 1.1 g/cm3 was the critical limit for seedling growth trembesi and the bulk density 1.2 g/cm3 was the critical limit for seedling growth meranti bapa (Shorea selanica) and sengon buto (Enterolobium cyclocarpum).
Keyword: Bogor Agricultural University (IPB), Enterolobium cyclocarpum, Samanea saman, Shorea selanica, Soil compaction

Judul: Respon Pertumbuhan Tiga Jenis Semai Terhadap Tingkat Kepadatan Tanah
Abstrak: Penyaradan di hutan alam umumnya menggunakan bulldozer. Hal ini memberikan dampak negatif terhadap lantai hutan berupa pemadatan tanah. Tanah yang padat memiliki porositas tanah yang rendah dan menyebabkan terbatasnya pertumbuhan akar tanaman, sehingga mengakibatkan terhambatnya penyerapan unsur hara dan mineral. Tujuan dari penelitian ini adalah membuat formulasi kepadatan tanah di laboratoriun dan menganalisis batas kritis pertumbuhan semai serta memilih jenis semai yang cocok untuk ditanam ditanah padat. Dalam penelitian ini, jenis semai yang digunakan diantaranya Kayu Afrika (Maesopsis eminii), Mahoni (Sweitenia machrophylla), dan Jabon (Antochepallus cadamba). Ketiga jenis semai tersebut ditanam diberbagai tingkat kepadatan tanah yaitu 0.9 g/cm³, 1.0 g/cm³, 1.1 g/cm³, 1.2 g/cm³ dan 1.3 g/cm³. Dalam formulasi kepadatan tanah, semakin tinggi jumlah pukulan pada proctor test, maka semakin tinggi pula tingkat kepadatan tanah. Semai yang ditanam ditanah padat dianalisis respon pertumbuhannya selama 6 bulan. Dari hasil analisis diketahui bahwa kepadatan tanah hanya berpengaruh pada respon pertumbuhan akar, sedangkan kepadatan tanah tidak berpengaruh terhadap pertumbuhan pucuk. Selain itu, batas kritis respon pertumbuhan pada jenis jabon terdapat pada kepadatan 1.2 g/cm³. Batas kritis kayu afrika terdapat pada kepadatan 1.1 g/cm³. Jenis mahoni merupakan jenis yang paling cocok untuk ditanam di berbagai tingkat kepadatan tanah. Hal ini dikarenakan tidak ada respon pertumbuhan semai yang dipengaruhi oleh kepadatan tanah. Untuk jenis jabon cocok untuk ditanam pada tingkat kepadatan tanah <1.2 g/cm³ atau setara dengan tanah yang dilalui bulldozer sebanyak 1 atau 2 rit. Untuk jenis kayu afrika cocok untuk ditanam pada tingkat kepadatan <1.1 g/cm³ atau setara dengan tanah yang dilalui bulldozer sebanyak 1 rit.
Keyword: penyaradan, kepadatan tanah, proctor test, respon pertumbuhan

Judul: Pemurnian dan karakterisasi protein inhibitor RNA helikase virus hepatitis C
Abstrak: Hepatitis C virus (HCV) infection is the second most common chronic viral infection in the world with global prevalence. This infection is contribution to chronic hepatitis and liver cirrhosis, often leading to hepatocellular carcinoma. There is no effective drug and vaccine available against HCV. The current standard treatment, a combination of pegylated interferon-α with ribavirin, is limited by its suboptimal response rate in a significant patient population, side effects, and affordability. Therefore, development of effective drug is needed. One approach to find out the candidate of antiviral drug is to discover the inhibitor of enzyme that essential for virus replication, such as RNA helicase. Streptomyces chartreusis 5-095 produce the inhibitor of HCV RNA helicase. The aim of this study was to purify the protein inhibitor which has inhibition activity against ATPase activity of RNA helicase HCV from S. chartreusis 5-095. The supernatant of culture S. chartreusis 5-095 exhibited high inhibiton activity against ATPase activity of RNA helicase HCV (approximately 72%) at 10 days of incubation. The extracellular protein inhibitor was partially purified by procedures of precipitation with ammonium sulfate to 65% saturation and gel filtration (Sephadex G50) using methanol water solution (4:6) as an eluen. The purity of protein inhibitor was monitored by SDS PAGE. The protein inhibitor showed a relative molecular mass were estimated to be 14 kDa and increased the purity 23,08 fold than those of the crude protein. The specific activity and IC50 after purification were 13,1338 U/mg and 0,0767 mg/mL, respectively. The activity of purified protein inhibitor showed its stability over pH range from 5-8 and optimum at pH 7,4. The inhibition activity showed its stability up to 70% at temperature 100 oC. The purified protein inhibitor relatively stable its activity at storage in the range of -20 oC to room temperature for 35 days.
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