Isolasi Dan Karakterisasi Kitinase Asal Bacillus Cereus 11 UJ

Kitinase merupakan enzim yang menghidrolisis polimer kitin menjadi oligomer kitin atau monomer Nasetilglukosamin.Penelitian ini bertujuan melakukan isolasi dan karakterisasi kitinase untuk memperoleh informasiaktivitas optimum kitinase asal B. cereus 11 UJ. Isolasi enzim kasar kitinase dan purifikasi parsial dilakukan denganpengendapan amonium sulfat jenuh 70% dan dialisis menggunakan membran selofan, selanjutnya dikarakterisasiuntuk memperoleh aktivitas optimum pada berbagai kondisi pH, suhu, waktu inkubasi, ion logam serta penentuannilai Km dan Vmaks. Hasil penelitian menunjukkan pemurnian kitinase dengan amonium sulfat 70% dan dialisismenunjukkan tingkat kemurnian masing-masing 2.40 kali dan 5.23 kali dibandingkan dengan ekstrak kasar enzim.Hasil karakterisasi menunjukkan bahwa kitinase asal B. cereus isolat 11 UJ mempunyai pH optimum 8, suhuoptimum 37oC, dan waktu inkubasi optimum selama 120 menit. Kation Mn2+, Fe2+, dan Cu2+ dengan konsentrasi10 mM diketahui dapat berfungsi sebagai inhibitor. Kitinase mempunyai nilai Km sebesar 29.71 μg/mL dan Vmakssebesar 1.035 x 10-1 μg/mL detik

Isolation and Disease Assessment of Xanthomonas Oryzae Pv. Oryzae From Java Island and Pathogenic Assay on Near Isogenic Lines with Different Resistant Genes

Bacterial leaf blight disease caused by Xanthomonas oryzae pv oryzae (Xoo) is one of the important bacterial diseases,which is very destructive to rice plant. In this study, seventy isolates of Xoo were collected from several regions inWest Java, Central Java, Yogyakarta and East Java provinces and ten isolates from ICABIOGRAD collection. Theaim of the study was to survey variation and distribution of the pathogen and to study the interactions between theisolates and near isogenic lines carrying specific genes for bacterial leaf blight resistance. Twenty Xoo isolates wererandomly chosen to assess the differential characteristics of ten near-isogenic rice lines in Indonesia. The resultsshowed that xa5 resistant gene was the highest effective against the majority of Xoo isolate, followed by Xa21, andXa7 combined with Xa4 as the background. These findings are useful for rice breeding programs in designing stablebroad-spectrum bacterial blight resistant rice cultivars