Judul: Antimicrobial Activity of Bacillus sp. to Xanthomonas oryzae pv. oryzae, Pseudomonas syringae pv. glycines, and Pseudomonas fluorescens.
Abstrak: Leaf blight disease caused by bacterial plant pathogen such as X. oryzae pv. oryzae and P. syringae pv. glycines had deathly effect to plants. The pathogens can be controlled by biological control using P. fluorescens or antimicrobial substances. The research studied the inhibition ability and production of antimicrobial substances produced by Bacillus sp. againts bacterial plant pathogen such as X. oryzae pv. oryzae, P. syringae pv. glycines, and biological control P. fluorescens. As many as 31 Bacillus sp. isolates isolated from forest soil was determined their antimicrobial activity against indicator bacteria using double layer method. The result showed that 13 isolates was able to inhibit Staphylococcus aureus, Eschericia coli, and X. oryzae pv. oryzae growth, 8 isolates could inhibit P. fluorescens A growth, 9 isolates could inhibit P. fluorescens B growth, and 8 isolates could inhibit P. syringae pv. glycines growth. Bacillus sp. F13 had the fastest inhibition and good efficiency against all indicator bacteria. Mixed culture competition test showed that this isolate had a broad spectrum inhibition activity, it was able to inhibit Gram positive and Gram negative bacteria. The isolate could inhibit growth of P. syringae pv. glycines and X. oryzae pv. oryzae up to 100%. The antimicrobial substance the isolate was produced in the late logarithmic growth phase.
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Judul: Activity of Bacillus cereus INT1c and Bacillus thuringiensis SGT3g AHL-Lactonase on Xanthomonas oryzae pv. oryzae and Pseudomonas syringae pv. glycinea Patogenicity Inhibition
Abstrak: Quorum sensing (QS) is a mechanism of communication between bacterial cells mediated by autoinducer (AI) signal molecules and depend on density of bacterial cells. AI is a signal molecules that secreted, accumulated, reabsorbed, and recognized by bacteria to regulate the expressions of target genes. QS on Gram-negative bacteria use N-acyl homoserine lactone (AHL) AI types as signal molecules. The high level of AHL in the cell will be responded by activating cell regulatory protein. Regulatory proteins help the expression of pathogens genes. Xanthomonas oryzae pv. oryzae and Pseudomonas syringae pv. glycinea are phytopatogenic Gram-negative bacteria that perform quorum sensing using Nacyl homoserine lactone (AHL) signal to regulate expression of their patogenicity genes. X. oryzae pv. oryzae causes pustule disease on paddy (Oryzae sativa) and P. syringae pv. glycinea cause leaf blight disease on soybean (Glycine max). One of natural approaches to inactivate their quorum sensing mechanisms was by degrading the signal molecules using AHL-lactonase from Bacillus cereus INT1c and Bacillus thuringiensis SGT3g. This study was conducted to test the ability of B. cereus INT1c and B. thuringiensis SGT3g AHL lactonase activity in degrading AHL to inhibit X. oryzae pv. oryzae and P. syringae pv. glycinea patogenicity. AHL degradation activity had been confirmed in B. cereus INT1c and B. thuringiensis SGT3g using Chromobacterium violaceum as bioindicator with inhibition index 0.23 and 0.12, respectively. Inhibition test by using tobacco plants was used to determine which is the most effective to inhibit phytopatogen in vivo. B. cereus INT1c was more effective to inhibit X. oryzae pv. oryzae patogenicity (85.62%) whereas B. thuringiensis SGT3g was more effective to inhibit P. syringae pv. glycinea pathogenicity, it was up to 90.51%. The highest inhibition activity of B. cereus INT1c was showed in IRBB7 varieties (93.69%) and the lowest was in Kencana Bali varieties (65.65%) on the in vivo test on paddy. Whereas in vivo on soybean test showed that B. thuringiensis SGT3g inhibition activity in Anjasmara and Wilis varieties were not much different, it was 96% and 95,35%, respectively.
Keyword: AHL-lactonase, Bacillus cereus, Bacillus thuringiensis, phytopatogen inhibition activity, quorum sensing

Judul: Studi kasus migran pedagang kaki lima di pasar Senen, Jakarta Pusat
Abstrak: Sejak Jakarta menjadi ibukota negara RI, Jakarta tidak pernah sepi dari arus migrasi penduduk. Masuknya para migran ke Jakarta disebabkan karena pertumbuhan fisik yang nyata, yaitu dari pembangunan gedung perkantoran, fasilitas hiburan dan lainnya, memberi daya tarik bagi orang bukan penduduk Jakarta. Termasuk di antara migran adalah kaum golongan kecil yang berasal dari kalangan sirkuit bawah desa. Alasan utama migrasi di sirkuit bawah, yaitu khususnya yang akhirnya bekerja sebagai pedagang kaki lima di Pasar Senen ini pindah ke Jakarta, adalahJakarta menawarkan kesempatan kerja bagi siapa saja yang mau bekerja. Karena di desa tak ada pekerjaan yang dapat menampung golongan muda, kaum migran meninggalkan desa menuju Jakarta. Pola migrasi masuk ke Jakarta tidak dipengaruhi oleh kemungkinan golongan muda mampir di kota-kota kecil sebelum tiba di Jakarta. Keberanian dan tekad bulat meninggalkan desa asal didorong pula oleh sumber cerita tentang Jakarta (saudara/kenalan) yang juga mengalami bahwa setiba di Jakarta mereka akan langsung bekerja. Pendidikan rendah, tidak memiliki ketrampilan, orang petani/buruh tani, merupakan bagian kecil latar tua belakang sosial migran pedagang kaki lima. Memperoleh pekerjaan apa saja asal halal pada mulanya, tempat tinggal dimana saja, modal kecil dan pendapatan harian yang rendah juga mewarnai hidup para migran pedagang kaki lima di Jakarta. Namun sekalipun demikian mereka tetap hidup, bahkan dapat mengirim uang ke desa asal, pulang ke desa minimum setahun sekali dan sedikit-sedikit mampumenabung. Bekerja sebagai pedagang kaki lima sudah ditekuni selama lebih dari lima tahun bahkan ada yang lebih dari tujuh tahun. Inipun dimulai setelah minimum selama dua tahun migran mengerjakan apa saja di Pasar Senen: yang penting dapat uang dan bisa hidup di Jakarta. Bahkan modal membuka usaha kaki lima diperoleh dari selama bekerja mula-mula itu. untuk pengumpulan upah Sekalipun terdapat kenaikan tingkat kehidupan sosial di kota dibandingkan dari desa, kaum migran pedagang lima di Pasar Senen ini tetap berada bawah kota. di kaki bawah sirkuit Ikatan-ikatan baru di kota hampir tidak terjadi kecuali ikatan-ikatan kedaerahan yang terus dipertahankan.
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