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THE GENUS CHITINOPHAGA ISOLATED FROM WANGGAMETI NATIONAL PARK AND THEIR LYTIC ACTIVITIES Meliah, Siti; Kusumawati, Dinihari Indah; Lisdiyanti, Puspita
JURNAL BIOLOGI INDONESIA Vol 14, No 2 (2018): JURNAL BIOLOGI INDONESIA
Publisher : Perhimpunan Biologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jbi.v14i2.3734

Abstract

 ABSTRACTThe utilization of bacterial enzymes in commercial industry, agriculture, waste treatment and health is preferred over other sources like plants and animals sources because they provide many advantages for different applications. The genus Chitinophaga which was first described as chitinolytic Myxobacteria, known as chitin destroyer or chitin eater due to their capability to hydrolyze chitin. The present study aims to isolate, characterize, identify, and assay the indigenous bacteria from Wanggameti National Park for their lytic activity againts chitin, cellulose and protein as an initial step in bio-prospecting of Sumba Island. Eleven yellow pigmented isolates were obtained from soil and decayed wood samples using ST21 and Water Agar media. They formed halo on VY/2CX medium. Physiological charazterization showed that two isolates were able to produce catalase but none of them produced urease. The phylogenetic analysis based on 16S rRNA gene sequences indicated that all isolates belong to the genus Chitinophaga that consisting of Chitinophaga filiformis, Chitinophaga ginsengisoli, Chitinophaga pinensis, and Chitinophaga sancti. They were deposited in InaCC under the name InaCC B1254 to InaCC B1264. Qualitative analysis of their lytic activity exhibited that all strains were able to lyse chitin and cellulose. The strains with the highest chitinase and cellulase activity are InaCC B1260 and InaCC B1258 strains, respectively, both of them are C. pinensis. Hereafter, C. filiformis showed the highest proteolytic activity in skim milk casein amongs all strains at 1.14±0.08. Keywords: Chitinophaga, chitinase, cellulase, protease, Sumba 
BAKTERI ENDOFIT YANG DIISOLASI DARI AKAR Eurycoma longifolia DAN POTENSINYA SEBAGAI PENGENDALI JAMUR PATOGEN TANAMAN Sulistiyani, Tri Ratna; Meliah, Siti; Damayanti, .
Jurnal Bioteknologi & Biosains Indonesia (JBBI) Vol. 7 No. 1 (2020): June 2020
Publisher : Balai Bioteknologi, Badan Pengkajian dan Penerapan Teknologi (BPPT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6303.007 KB) | DOI: 10.29122/jbbi.v7i1.3997

Abstract

Eurycoma longifolia (pasak bumi) is known as a medicinal plant that contains biologically active compounds. Studies on endophytic bacteria associated with pasak bumi and their biocontrol activities have not been widely reported. The objective of this study is to isolate potential endophytic bacteria associated with E. longifolia possessing biocontrol activity against plant pathogenic fungi, Sclerotium rolfsii, Fusarium solani, F. oxysporum, and Colletotrichum gloeosporioides. Endophytic bacteria were isolated from the roots of E. longifolia using the plant piece method and identified based on 16S rRNA genes analysis. Antagonist test of bacterial isolates was conducted by dual confrontation method. The mechanisms of fungal growth inhibition were evaluated based on their ability to produce hydrolytic enzymes, antibiotic, and volatile organic compounds. Two isolates were obtained and identified as Stenotrophomonas maltophilia (Apb1) and Serratia marcescens (Apb2). Apb2 was able to inhibit the growth of four tested fungi and showed protease, chitinase as well as cellulase activities. The crude extract and volatile organic compound produced by Apb2 were active against F. solani growth.Keywords: biocontrol, endophytic, Eurycoma longifolia, fungi, inhibition mechanism ABSTRAKEurycoma longifolia (pasak bumi) dikenal sebagai tanaman obat yang mengandung beberapa senyawa aktif secara biologis. Penelitian mengenai bakteri endofit yang berasosiasi dengan tanaman pasak bumi berikut aktivitas biokontrolnya belum banyak dilaporkan. Penelitian ini bertujuan mengisolasi bakteri endofit potensial dari tanaman E. longifolia yang memiliki aktivitas biokontrol terhadap empat strain uji jamur patogen tanaman, yaitu Sclerotium rolfsii, Fusarium solani, F. oxysporum, dan Colletotrichum gloeosporioides. Bakteri endofit diisolasi dari akar E. longifola menggunakan metode plant piece dan diidentifikasi berdasarkan analisis gen 16S rRNA. Uji antagonis isolat bakteri dilakukan dengan metode konfrontasi ganda. Mekanisme penghambatan jamur patogen tanaman dievaluasi berdasarkan kemampuannya dalam memproduksi enzim hidrolisis, senyawa antibiotik, dan senyawa organik volatil. Dua isolat bakteri endofit berhasil diperoleh dan teridentifikasi sebagai Stenotrophomonas maltophilia  (Apb1) dan Serratia marcescens (Apb2). Isolat Apb2 mampu menghambat pertumbuhan keempat jamur yang diuji dan menunjukkan aktivitas protease, kitinase dan selulase. Ekstrak kasar dan senyawa organik volatil yang dihasilkan oleh isolat Apb2 aktif menghambat pertumbuhan F. solani.
Xanthomonas oryzae pv. oryzae BAKTERI PENYEBAB HAWAR DAUN PADA PADI: ISOLASI, KARAKTERISASI, DAN TELAAH MUTAGENESIS DENGAN TRANSPOSON Wahyudi, Aris Tri; Meliah, Siti; Nawangsih, Abdjad Asih
Makara Journal of Science Vol. 15, No. 1
Publisher : UI Scholars Hub

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Abstract

Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis. X. oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) of rice (Oryza sativa L.), a major disease that constrains production of the staple crop in many countries of the world. Identification of X. oryzae pv. oryzae (Xoo) was conducted based on the disease symptoms, pathogenicity, morphological, physiological, and genetic characteristics of bacterial cultures isolated from the infected plants. Fifty bacterial isolates predicted as Xoo have been successfully isolated. They are aerobic, rod shaped, and Gram negative bacteria. The isolates were evaluated for their hypersensitivity in tobacco and pathogenicity in rice plant. Fifty isolates induced hypersensitive reaction in tobacco and showed pathogenicity symptom in rice in different length. Based on physiological test, hypersensitivity and pathogenicity reactions, three bacterial isolates strongly predicted as Xoo, i.e. STG21, STG42, and STG46, were non indole formation, non pigment fluorescent, hydrolyzed casein, catalase activity positive, but negative oxidase. Partial sequencing of 16S rRNA genes of STG21 and STG42 showed 80% and 82% homology with X. oryzae, respectively, while STG46 showed 84% homology with X. campestris. Mini-Tn5 transposon mutagenesis of STG21 generated one of the mutants (M5) lossed it’s ability to induce hypersensitive reaction in tobacco plant and deficient in pathogenicity on rice. The lesion length of rice leaf caused by the mutant M5 decreased up to 80%.
Predatory Activity of Myxobacteria Corallococcus exiguus against Soil Inhabiting Bacteria Meliah, Siti; Nurindahsari, Miranti; Purnaningsih, Ismu
Biota : Jurnal Ilmiah Ilmu-Ilmu Hayati Vol 8, No 1 (2023): February 2023
Publisher : Universitas Atma Jaya Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24002/biota.v8i1.5710

Abstract

Prokaryotic micropredators, including myxobacteria, shape the structure of the community in the soil as they prey on other microorganisms. Their unique behavior in nature has raised the interest in exploiting these bacterial groups to combat the threatening antibiotic resistance. The objective of this study is to assay the antibacterial activity of Corallococcus exiguus, a member of myxobacteria, based on their predation ability against soil inhabiting bacteria. A total of 17 soil bacteria from different taxa were preyed upon three C. exiguus isolates on TPM buffer agar medium. Based on the predation assay, all the three isolates actively killed all the Gram-negative Alphaproteobacteria and Betaproteobacteria members used in this study. Protease producing assay using casein as substrate revealed that these isolates were able to break down the protein with lytic index up to 1.33 ± 0.10. Their ethyl acetate extracts slightly inhibited the growth of one selected Gram-positive bacterium. Hydrolytic enzyme and secondary metabolite produced by C. exiguus are considered to play an important role in their predation activity.