Judul: ABSTRACT  HENDRA MUNANDAR. Detection of Nitrilase Gene as Probe for Detecting Rhodococcus Degrading Nitrile in Sponge-Associated Microbe Community
Abstrak: Biodegradasi nitril telah lama dikaji dan semakin intensif, hal ini sehubungan dengan peranan sistem biokonversi nitril yang banyak diaplikasikan sebagai agen biokatalis dalam menghasilkan berbagai senyawa kimia intermediat. Salah satu enzim yang terlibat dalam biodegradasi nitril adalah nitrilase (EC 3.5.5.1) yang berfungsi menghidrolisis nitril menjadi asam karboksilat dengan melepaskan amonium. Nitrilase telah banyak dipakai di industri, salah satu contohnya adalah produksi lipitor sebagai senyawa statin yang berfungsi menurunkan tingkat kolesterol oleh Pfizer. Meningkatnya perhatian kepada nitrilase mendorong usaha-usaha eksplorasi untuk mendapatkan sumberdaya genetik nitrilase, karena masih terbuka peluang besar untuk menemukan nitrilase dengan aktivitas dan tingkat kestabilan yang tinggi. Kelompok bakteri yang banyak dilaporkan sebagai pendegradasi nitril yang unggul adalah Rhodococcus, sehingga kemungkinan besar berpotensi menyimpan sumber daya genetik nitrilase dengan kemampuan tinggi. Eksplorasi yang dilakukan untuk mendapatkan nitrilase umumnya dari daerah yang tercemar atau terpapar limbah nitril yang terbatas pada wilayah daratan (terestrial), dan masih jarang yang melakukan dari lingkungan laut. Sebagai bakteri Gram positif Rhodococcus memiliki daya tahan hidup yang luar biasa hingga mampu hidup di lingkungan yang cukup ekstrim, termasuk di daerah dengan kadar salinitas yang tinggi. Hal ini terungkap dari penelitian yang menemukan spesies Rhodococcus hidup di dasar (sedimen) laut dalam, sehingga potensi menemukan bakteri tersebut di lingkungan laut terbuka luas. Salah satu potensi sumber daya mikroba di laut adalah mikroba asosiasi spons, yang telah banyak diteliti menyimpan banyak potensi untuk bidang farmasi dan kimiawi. Tingginya komposisi mikroba dalam tubuh spons yang mencapai 40-60% dari bobot tubuh spons menjadikan spons tampak sebagai fermentor alami, dengan kepadatan mikroba mencapai 109 sel/ml spons merupakan peluang besar untuk digali potensinya. Penelitian ini bertujuan untuk melacak Rhodococcus sebagai bakteri pendegradasi nitril yang hidup sebagai bakteri asosiasi spons, dengan cara melacak keberadaan gen nitrilase sebagai salah satu enzim yang berperan dalam sistem biodegradasi nitril mikrobial. Metode yang dipakai didasarkan atas reaksi polimerase chain reaction (PCR) menggunakan primer spesifik untuk gen target, sehingga diperlukan primer yang tepat agar bisa mengamplifikasi gen nitrilase dari DNA genom total bakteri asosiasi spons. Untuk mendapatkan primer yang tepat diperlukan DNA acuan sebagai template bagi pengujian primer hasil desain, oleh karena itu langkah pertama yang dilakukan adalah penapisan untuk menemukan isolat kontrol positif dari kelompok Rhodococcus. Penapisan dilakukan dengan menggunakan media selektif yang hanya memakai senyawa nitril sebagai satu-satunya sumber nitrogen, karbon dan energinya. Isolat yang mampu tumbuh menandakan mampu mendegradasi senyawa nitril dan memiliki sistem enzim pendegradasi nitril., Nitrilase, an hydrolizing enzyme that convert nitrile compounds into corresponding carboxilic acid, is important enzyme for producing several intermediate compounds. Related to stability as an encounter problem of nitrilase, it is required new genetic resources to acquire the better enzyme. Related to megabiodiversity of Indonesia’s natural resources, one of potential sources to be explored is from sponge-microbe association. Gene encoded nitrilase was screening by PCR method with H1 primer that designing based on Rhodococcus genus that known as superior nitrile degrading bacteria. Formerly determining positive control isolate, and TPIK isolate that previously identified as Rhodococcus pyridinivorans was selected. Amplification to the positive control isolate (TPIK) was resulted 914 bp fragment which identified as nitrilase gene that 98% has similar with
Keyword: Rhodococcus, Nitrilase, Nitrile, Biodegradation, Songe-associated microorganism

Judul: Penapisan Bakteri Rhizosfer Padi Penghasil Nitrogenase yang Tahan Kondisi Salin dan Identifikasi Gen nifH
Abstrak: The ability of nitrogen fixing by rhizosfer bacteria could be used to decrease salinity impact in coastal rice field. It was caused by nitrogenase, encoded by nifH gene in component II. The objectives of this research were to screen of rhizosfer bacterias that have the nitrogenase activity in saline condition and identify the presence of nifH gene. The fifty isolates of rhizosfer bacteri isolated from coastal rice field Eretan and Patimban region, West Java was analyzed. Five isolates showed the nitrogenase activity under saline condition, are Er B1 3, Er B1 4, Er B1 9, Er B2 10 dan Ptb B1 4. The identification of nifH gene from these 5 samples using polymerase chain reaction (PCR) showed that the size is ~360 bp. The highest activity of nitrogenase used acetylene reduction assay (ARA) was showed by Er B2 10 is 4,4081 μmol.mL-1hour-1.
Keyword: rhizosfer bacteria, nitrogenase activity, nifH gene, coastal soil, ARA

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite