Judul: Hubungan beberapa sifat fisik, kimia dan aktivitas mikroorganisme tanah dengan kemantapan agregat
Abstrak: Penelitian ini bertujuan untuk membandingkan hubungan beberapa sifat fisik, kimia dan aktivitas mikroorganisme tanah dengan kemantapan agregat dan menentukan faktor yang paling berperanan dalam kemantapan agregat. Untuk ini digunakan 5 jenis tanah, diambil pada kedalaman O 20 cm dan 40 60 cm. Indeks stabilitas agregat ditetapkan dengan metode pengayakan kering dan basah. Parameter lain yang dianalisis meliputi tekstur, nilai SAR, kandungan bahan organik, nilai COLE, aktivitas mikroorganisme, kandungan oksida Al dan Fe, porositas total dan distribusi ukuran pori. Liat, bahan organik dan oksida Al dan Fe diperlukan untuk pemantapan agregat, tetapi peningkatan secara individu bahan tersebut tidak menjamin terbentuknya agregat yang lebih stabil. Hasil analisis regresi sederhana diperoleh korelasi sangat nyata antara persentase pasir dan nisbah bahan organik terhadap liat dengan ISA, serta diperoleh korelasi nyata untuk nisbah oksida Al dan Fe terhadap liat, dan persentase liat. Untuk analisis regresi linier berganda diperoleh korelasi nyata antara persentase pasir, persentase liat, PDL, nilai COLE, oksida Al dan Fe serta kandungan bahan organik dengan ISA.
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Judul: Hubungan antara beberapa sifat fisik, kimia dan biologi tanah dengan air tanah pada berbagai tekstur tanah
Abstrak: Penelitian ini dilakukan di Laboratorium Fisika, Kimia den Kesuburan, Mineralogi, dan Biologi Tanah, Jurusan Tanah, Fakultas Pertanian, Institut Pertanian Bogor dan Laboratorium Agronomi Balai Penelitian Tanaman Pangan Cimanggu Во- gor mulai bulan Maret sampai dengan bulan September 1987. Tujuan Penelitian melihat hubungan antara beberapa sifat fisik, kimia dan biologi tanah dengan retensi air tanah pada berbagai tekstur tanah serta menduga parameter sifat fisik, kimia dan biologi tanah yang paling berperanan dalam menentukan retensi air tanah. Sebagai bahan penelitian digunakan Grumusol Cihea, Podsolik Jasinga, Andosol Sukamantri, Regosol Sindang Barang dan Latosol Darmaga, masing-masing diambil pada kedalaman 20 cm dan 40 - 60 cm. Contoh tanah berupa tanah utuh, agregat utuh dan tanah terganggu. Selain bahan di atas ju- ga digunakan berbagai macam bahan analisis sifat-sifat fisik, kimia dan biologi tanah yang ditetapkan. Analisis retensi air tanah dilakukan dengan metode kurva pF (plate dan membrane apparatus). Sedangkan parameter-parameter yang dianalisis, yang diduga mempunyai hubuzgan erat dengan retensi air tanah diantaranya: tekstur, selisih pH H2O dan pH KCl (APH), bobot isi, porositas total, indeks stabilitas agregat (ISA), sodium adsorption ratio (SAR) dan aktivitas mikroorganisme…dst
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Judul: Development of DNA Vaccine Encoding Glycoprotein of Koi Herpes Virus Using Local Isolate.
Abstrak: The aim of this research was to develop DNA vaccine of Koi Herpesvirus in carp. Glycoprotein gene originated from ORF 25 KHV virus that is 1.8 kbp in size, is a potential gene in DNA vaccine construction. The sequencing and similarity analysis of the gene using BLAST software showed that this gene is a GP25 gene and was found to be very similar (99%) to GP25 of KHV virus from the USA and Israel. When this GP25 gene was ligated with pGEMT Easy (pT, 3 kbp in size) vector, plasmid size was increasing up to 5 kb. Following this, a digestion of pT-GP25 plasmid using Sal I enzyme was applied resulted in a GP25 fragment (1.8 kbp). Subsequently, pAct-D6 with a size of 8.5 kbp was also cut using the same enzyme to eleminate a D6 gene with a size of 1.6 kbp. GP25 gene was then ligated with pAct resulted a pAct-GP25 plasmid with a size of 8.8 kbp. As there was only one restriction site applied, ligation can be occurred in two different directions. Thus, in order to determine the plasmid with the desired direction PCR analysis was carried out, and plasmid with the right direction was the one that sized approximately 2.1 kbp (no. 6, 17 and 20). High level of GFP gene expression was detected in all tissues analyzed, i.e. kidney, gil, spleen, and muscle 24 hours after injection which indicated that β-actin promoter of Japanese medaka could be active in common carp. Although not as high as on 24 hours, expression was still detected until day 7 and disappeared after day 28 post injection indicating that pAct-GFP can be remained and β-actin promoter of Japanese medaka can be active in muscle, gills and kidney at least a week after injection. The result of RT-PCR analysis on pAct-GP25 injected common carp showed that GP25 gene expression can be detected 14 days after injection in all tissues observed. The expression level differences between GFP and GP25 genes possibly related to the primer sensitivity on annealing process to cDNA template and the size of PCR targeted DNA fragment, as smaller PCR targeted product will be easier to be amplified than a bigger one. The length of PCR targeted DNA with GP25 primer was 1.8 kbp whereas GFP gene was 0.6 kbp.The challenge test on common carp results showed that all unvaccinated and negative control (not infected with KHV) was alive until the end of the experiment. Whereas, the survival of fish vaccinated with a dose of 12.5 was ranged from 60.9 and 96.7%. In relation to the activity of β-actin promoter that was used in this DNA vaccine, gene expression was occured 24 hours after vaccination and remained until 2 weeks. The control fish that was not injected by GP25 showed no GP25 expression either in the observed tissues or organs and resulted in a lower survival, i.e. 23.3%. The challenge test results has indicated that the fish vaccinated with GP25 at doses of 7.5 and 12.5 μg/100μL were able to produce KHV glycoprotein in their body which would be
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