Isolasi dan Karakterisasi Aktinomisetes Penghasil Antibakteri Enteropatogen Escherichia coli K1.1, Pseudomonas pseudomallei 02 05, dan Listeria monocytogenes 5407

Isolation and Characterization of Actinomycetes ProducingAntibacterial Compound into EnteropatogenikEscherichia coli K1.1, Pseudomonas pseudomallei 02 05and Listeria monocytogenes 5407. Dwi N. Susilowati,Ratih D. Hastuti, and Erny Yuniarti. The resistance ofbacterial pathogens to some antibacterial agents and sideeffects of the antibacterial usage demanded discovery ofnew effective, safe, and active antibacterial compounds.Some pathogenic bacteria, such as enteropathogen Escherichiacoli (EPEC) that cause diarrhoea on children andinfants, Pseudomonas pseudomallei that cause melioidosison human and animal, and Listeria monocytogenes thatcause listeriosis on newly born babies mortality and death ofpregnant woman. Actinomycetes is the largest bacterialgroup that produce antibiotics. More than 10,000 antibacterialcompounds had been discovered, two-third ofthem were produced by this bacterial group. A study wasdone to isolate and characterize Actinomycetes producingantibacterial compounds effective against EPEC K1.1 and P.pseudomallei 02 05. Soil samples were taken from 39locations in Indonesia and 115 actinomycetes isolates wereobtained. Two of the isolates, i.e., isolate A3.5 that waseffective against P. pseudomallei 02 05 and isolate F6.1 thatwas effective against EPEC K1.1 evaluated further. Theisolate A3.5 had an optimum time 72 hours to produce antibacterialcompound, while F6.1 took 96 hours. The antibacterialcompounds produced by both isolates were dissolvein the a 70% ethyl acetate solution, but not in a 40oCwarm methanol solution because it is very dissolved. Theantibacterial compound extracted from the isolate A3.5 hada similar effectiveness to antibiotics bacithracyn 10 unit andneomycin 30 g. On the other hand, the antibacterialcompound extracted from isolate F6.1 had a similar effectivenessto antibiotics colistin 10 g and doxyciclin 30 g.Further identification of the isolates suggested that both ofthem belongs to the genera Streptomyces

Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight (BLB), is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD) with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC) was not significantly different to that on control plants (P > 0.05). However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05). Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02) were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight (BLB), is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD) with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC) was not significantly different to that on control plants (P > 0.05). However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05). Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02) were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers

Genus Diversity of Actinomycetes in Cibinong Science Center, West Java, Indonesia

Actinomycetes are microorganisms that play important role to support human health and  known as soil microorganisms. The aim of the research was to describe genus diversity of actinomycetes in Cibinong Science Center (CSC), West Java. Samples for isolation were soil and plant litters. The samples were air dried and ground. We employed isolation methods: dry heat (DH), sodium dodecyl sulphates-yeast extract (SDS-YE), rehydration and centrifugation (RC), and oil separation (OS). A total of 263 isolates of actinomycetes were isolated in CSC, in 2004-2006. Totally 58, 144, 50, and 11 isolates were isolated under each isolation methods, respectively. All isolates were identified using the 16S rRNA gene sequencing method. The results showed that the isolates were belonged to the family Kineosporiaceae, Micromonosporaceae, Nocardiaceae, Pseudonocardiaceae, Streptomycetaceae, Streptosporangiaceae, Mycobacteriaceae, Nocardioidaceae, Nocardiopsaceae, and Thermomonosporaceae. There were 23 genera under those families. Homology value of the isolates based on BLAST search using 16S rRNA gene sequence data as queries showed that 136, 91, 30, and 6 isolates were ≥99, 98, 97, and ≤96%, respectively, compared to the known sequence in data base. The later 6 isolates were interesting for further identification leading to new taxa. Recognized species of Streptomyces genera under the member of the Streptomycetaceae were dominant among other isolates