Judul: Konstruksi Gen Penyandi Plantaricin S dari Lactobacillus plantarum S34
Abstrak: Bacteriocins are antibacterial peptides that commonly used as food biopreservative. Bacteriocins were produced by both either Gram positive or Gram negative bacteria, one of them is Lactobacillus plantarum S34 isolated from beef bekasam. L. plantarum S34 produced bacteriocins called plantaricin. PlnS gene is gene that encoding plantaricin. The study purposed is to isolate plnS gene from L. plantarum S34. The plnS gene amplified by PCR (Polymerase Chain Reaction) technique, and then cloned into cloning vector pGEM-T Easy and transformed into E. coli DH5α. Transformation gene using heat shock method. Selection of transformants using the blue and white colonies. Gene amplification produces plnS gene amplicon size about ±500 bp. PlnS gene ligation with pGEM-T Easy (3015 bp) vector generating plasmid size about ±3500 bp. The confirmation of white colonies from blue-white screening was carried out with PCR colony, generated amplicons size was about ±500 bp. Recombinant plasmid in colony 2 was confirmed by restricition analysis using SalI and NcoI. The result showed that the gene insert had expected size ±500 bp.
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Judul: Konstruksi Vektor Ekspresi Dari Gen Plnw Dari Lactobacillus Plantarum U10 Dan Ekspresinya Di Lactococcus Lactis
Abstrak: Lactobacillus plantarum U10 yang diisolasi dari Tempoyak menghasilkan bakteriosin jenis plantarisin (disandikan oleh gen pln) yang memiliki aktivitas penghambatan terhadap beberapa bakteri patogen. Gen-gen plantarisin tersebar ke beberapa operon yang masing-masing memiliki fungsi tersendiri dalam sistem biosintesis plantarisin. Terdapat lima operon yang terdiri dari plnABCD, plnEFI, plnJKLR, plnMNOP dan plnGHSTUVW. Operon plnGHSTUVW menyandikan protein yang berperan sebagai ATP-binding cassette (ABC) transporter dan beberapa protein membran yang belum diketahui fungsinya, termasuk plnW. Hasil-hasil studi terdahulu menunjukkan bahwa beberapa lokus bakteriosin (termasuk plantarisin) menyandikan protein yang tergolong dalam protein Abi (no. aksesi Pfam PF02517) jenis CAAX protease. Beberapa protein Abi dalam lokus ini (PlnI, PlnL, SkkI, PncO dan SagE) diketahui berperan membentuk imunitas terhadap aktivitas bakteriosin. Selain itu, protein-protein tersebut memiliki motifmotif terkonservasi yang mirip dengan plantarisin W (PlnW). Penelitian ini bertujuan untuk mengkarakterisasi gen plnW asal L. plantarum U10 dan mengklonnya ke dalam vektor ekspresi dan mengekspresikannya dalam L. lactis, serta untuk mengetahui aktivitas PlnW dalam menghambat aktivitas bakteriosin. Penelitian ini dimulai dari amplifikasi gen plnW dari DNA kromosom L. plantarum U10, kemudian mengklonnya ke dalam vektor pengklonan pGEM-T Easy dan vektor ekspresi pNZ8148. Vektor ekspresi yang telah membawa gen plnW diintroduksikan ke inang L. lactis NZ3900 menggunakan teknik elektroporasi. Analisis tingkat ekspresi PlnW dilihat melalui pengaruh dosis nisin dalam menginduksi L. lactis. Sifat resisten bakteriosin dilihat dari kemampuan pertumbuhan L. lactis pembawa gen plnW ketika dipaparkan bakteriosin. Fragmen DNA berukurun 1033 bp yang mengandung plnW berhasil diamplifikasi dari DNA kromosom L. plantarum U10. Hasil PCR dengan ukuran 1033 bp tersebut mengandung 687 bp plnW yang menyandikan protein PlnW berukuran 25.08 kDa. PlnW L. plantarum U10 asal pangan Tempoyak memiliki rata-rata tingkat kemiripan sebesar 98.32% terhadap PlnW L. plantarum dari sumber lain. Terdapat dua perbedaan asam amino pada posisi ke-77 (arginin  triptofan) dan posisi ke-160 (asam aspartat  glisin). Hasil analisis lokasi PlnW menunjukkan bahwa PlnW terdapat pada daerah transmembran yaitu pada daerah urutan asam amino ke-14 sampai 37, 42 sampai 59, 84 sampai 100, 186 sampai 205, serta 212 sampai 228. Gen plnW berukuran 687 bp telah teramplifikasi dari pGplnWU10 menggunakan pasang primer plnW-NcoI_F dan plnW-HindIII_R. Gen tersebut berhasil disisipkan ke daerah multiple cloning site (MCS) pada vektor ekspresi pNZ8148 sehingga terbentuk pNZ8148-WU10, dan pNZ8148-WU10 telah berhasil diintroduksikan ke dalam E. coli MC1061. Vektor pNZ8148-WU10 berhasil diperbanyak di E. coli transforman, dan telah diintroduksikan ke L. lactis NZ3900. Efisiensi transformasi meningkat seiring dengan meningkatnya kadar vektor yang diintroduksikan ke L. lactis. Efisiensi tertinggi sebesar (7.2 x 103) ± 100 CFU/μg DNA dicapai ketika kadar vektor/plasmid sebesar 1 μg. L. lactis yang membawa vektor pNZ8148-WU10 berhasil mengekspresikan plnW. Protein PlnW berukuran 25.3 kDa, terlihat pada bagian sampel rekombinan. Konsentrasi protein meningkat secara cukup signifikan ketika diinduksi nisin. Konsentrasi protein tertinggi (1.55 ± 0.04 mg/mL) dicapai ketika diinduksi 10 ng/mL nisin. Selain itu, PlnW mempunyai aktivitas protease sebesar 2.22 ± 0.05 U/mL dengan aktivitas spesifik sebesar 1.65 ± 0.03 U/mg protein ketika diiduksi dengan 50 ng/mL nisin. PlnW mempunyai aktivitas imunitas terhadap plantarisin dan imunitas silang terhadap jenis bakteriosin lain yaitu pediosin, fermentsin dan acidosin. Hilangnya sensitivitas L. lactis transforman yang mengandung PlnW
Keyword: Plantarisin, PlnW, pNZ8148, L. lactis, imunitas

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