Growth Inhibition of Aspergillus Spp. by Endophytic Bacteria

Aspergillus spp. (A. Niger, A. flavus, and A. fumigatus) contaminate food commodities through production of secondary metabolites (mycotoxins) and aspergillosis, and thus pose severe hazard to human and animal health. Hence, the inhibition of mycotoxin-producing fungi on agricultural storage commodities needs to be considered. The aims of this study were to evaluate endophytic bacteria isolated from rice tissues that inhibit Aspergillus spp. growth, as well as to characterize the selected isolates morphologically and biochemically. Dual culture and disk diffusion method tests on 155 endophytic bacteria obtained three isolates, i.e. FB-Endo 65, FB-Endo 73, and FB-Endo 95, which showed inhibition zone from 13 to 17 mm against Aspergillus spp. growth. The inhibition zone and quantity of antifungal compounds increased positively with the length of incubation periods from 0 to 6 days. Antifungal compounds from the three isolates were insoluble in ethyl acetate, but soluble in methanol. The methanol soluble substance(s) from FB-Endo 73 showed higher inhibition zone than that of the other isolates. This result indicated that all three isolates produced strong antifungal activity. Morphological and biochemical identifications of the isolates revealed that all isolates belonged to the genus Bacillus sp. Further studies include identification and production methods of antifungal compounds of those endophytic bacteria and their application on stored seeds

Analisis Aktivitas Nitrogenase dan Gen Nifh Isolat Bakteri Rhizosfer Tanaman Padi dari Lahan Sawah Pesisir Jawa Barat

Penambatan nitrogen oleh bakteri rhizosfer dapat dimanfaatkan untuk menyiasati dampak salinitas pada tanah sawah pesisir. Kemampuan tersebut disebabkan oleh aktivitas nitrogenase yang disandikan gen nifH pada komponen II. Penelitian ini bertujuan menganalisis aktivitas nitrogenase pada kondisi salin dan mengidentifikasi gen nifH. Sebanyak 50 isolat bakteri rhizosfer asal tanah sawah pesisir daerah Eretan dan Patimban, Jawa Barat telah dianalisis. Lima isolat yang menunjukkan aktivitas nitrogenase pada kondisi salin adalah Er B1 3, Er B1 4, Er B1 9, Er B2 10, dan Ptb B1 4. Gen nifH kelima sampel diidentifikasi menggunakan PCR menghasilkan amplikon berukuran ~360 bp. Aktivitas nitrogenase tertinggi berdasarkan Analisis Reduksi Asetilen (ARA) diperoleh pada isolat Er B2 10 yang memiliki kekerabatan terdekat dengan bakteri Providencia sp. Hasil yang diperoleh membuktikan bahwa beberapa bakteri asal sawah pesisir dapat menambat nitrogen pada kondisi salin

Virulensi Phytophthora Capsici Asal Lada terhadap Piper Spp.

Lada telah dibudidayakan secara luas di Indonesia dan sebagian besar diusahakan oleh petani bermodal kecil. Salah satu kendala dalam budi daya lada di Indonesia ialah penyakit busuk pangkal batang lada yang disebabkan oleh Phytophthora capsici. Salah satu USAha pengendalian yang dianggap efektif ialah menggunakan varietas tahan, tetapi keragaman genetik lada budi daya sempit. Hal ini merupakan kendala dalam program perbaikan varietas. Untuk itu perlu dicari sumber gen ketahanan dari spesies lainnya, yaitu Piper betle, P. colubrinum, P. cubeba, P. hispidum, dan P. retrofractum; sedang P. nigrum digunakan sebagai pembanding. Inokulasi dilakukan dengan cara meletakkan potongan hifa P. capsici pada permukaan bawah daun ketiga dan keempat dari masing-masing Piper spp. Sebanyak 50 isolat P. capsici asal lada yang diperoleh dari berbagai lokasi digunakan dalam penelitian. Daun yang telah diinokulasi diinkubasi pada kotak yang dijaga kelembabannya pada suhu kamar. Luas nekrosa yang terbentuk diukur 72 jam setelah inokulasi. Data luas nekrosa dianalisis secara statitistik untuk melihat ketahanan masing-masing Piper spp. terhadap isolat P. capsici yang digunakan. Hasil analisis menunjukkan bahwa P. betle, P. cubeba, dan P. retrofractum terdapat dalam kelompok yang sama dengan P. nigrum, sedangkan P. colubrinum dan P. hispidum terdapat pada kelompok yang lain. Hasil analisis menunjukkan, 50 isolat P. capsici yang digunakan terbagi ke dalam tiga kelompok, yaitu kelompok yang dapat menyerang semua Piper spp., kelompok yang efektif menyerang P. betle, P. cubeba, P. retrofractum, dan P. nigrum; serta kelompok yang efektif menyerang P. colubrinum dan P. hispidum. Data pengujian menunjukkan adanya variasi virulensi yang luas pada P. capsici dan tidak semua Piper spp. berpotensi digunakan sebagai sumber ketahanan

Identifikasi 26 Isolat Bakteri Endofitik Dan Filosfer Padi Dengan Analisis Sekuen16s Rdna [Identification of 26 Endophytic and Phyllosphere Bacteria Isolated From Rice by 16s Rdna Sequence Analyses]

The research was subjected to identify 26 endophytic and phyllosphere bacteria isolated from 4 rice varieties using sequencing method of 16S rDNA.The sequences were then aligned with reference sequence from Gen-Bank data library by BLAST program from NCBI to find the most related identity of the isolates analysed.The sequencing analysis revealed that some isolates have a high identity to Staphylococcus and Serratia (5 isolates each), Bacillus (4 isolates), Microbacteria (3 isolates), Pseudomonas (2isolates) and Klebsiella, Acidovorak, Bulkholderiaceae, Agrobacterium and Shewanella (1 isolate each). No specific isolate dominated in both endophytic and phyllosphere group, nor host-specific isolate found in the four rice varieties

Iodine Salt Consumption in Indonesian Households: Baseline Health Survey 2007

Background: Iodine Deficiency Disorder (100) reduction program has been implemented since 1976. According to the National Economic Survey 2002, the average consumption of iodized salt was 6. 26 grams. The results of Iodine Salt Survey (SGY) 2003 showed that the consumption of iodine salt at the household level was 73.2%, meanwhile, the baseline health survey (Riskesdas) 2007 showed there was reduction of iodine salt consumption towards 60.2%. Methods: Type of study was secondary data analysis with cross-sectional design utilizing the Riskesdas 2007's data. Sample was selected purposively according to the previous SGY's survey based on the endemically criteria namely highly endemic, mediocre and non endemic. Results: The results of the analysis were there was discrepancy of iodine salt consumption among urban and rural areas as well as mother's education level. The iodine salt consumption was higher in the urban area (65.5%) compare to the rural area (52.9%). The higher the education of mothers the better the iodine salt consumed. The USAge of iodine salt in the households based on salt quick test was 60.2%, meanwhile, according to the salt titration it was only 23.4%. The results of Excretion Iodine Urine showed that the iodine intake among the school children (age of 6-12 years old) was 12.8% and was still below the cut-off point prevalence, which is greater than 50%. The conclusion of this analysisis that there was evidence of iodine salt reduction consumed at the household level. Conversely, there was inclination of the percentage of iodine urine level among the school children in Indonesia in the year 2007. It is recommended that policy analysis need to be conducted due to the achievement of the Universal Salt iodization target, especially in the endemic areas to asses the existence of the IDO prevalence

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

Pengaruh Hormon Asam Indol Asetat Yang Dihasilkan Azospirillum SP. Terhadap Perkembangan Akar Padi

Free-living bacteria of thegenus Azospirillum live in close association with rice roots.This bacteria produced indole acetic acid (IAA), a plantgrowth hormon, to the environment. IAA was isolated fromcultures of Azospirillum strains and investigated for its effecton root development and plant height of rice variety IR64 invitro. Rice cultures of variety IR64 were grown in vitro andinoculated with cultures of Azospirilllum. Production of IAAby the bacterium during its growth period in rice culture mediumcontaining different levels of nitrogen was observed.Results of the experiment showed that strains AzospirillumAz15 and Az44 had a high ability to produce IAA, i.e., 57.93μg/ml at 12 days after incubation (DAI) and 40.42 μg/ml at 7DAI, respectively. The IAA production pattern of AzospirillumAz15 and Az44 in the liquid medium were fluctuativeuntil the end of the incubation period, while that of the strainAz7 was linier. Strain Az7 gave a better effect on the rootdevelopment and plant height than strains Az15 and Az44.Treatment combination of strain Az7 and 100% nitrogen gavehighest root development. High level of nitrogen increasedIAA content in the uninoculated culture, while low IAAcontent on the inoculated one. Inoculation the culture withstrain Az7 together with 50% nitrogen application resulted inthe IAA content, root dry weight, root length, fiber root number,and plant height as high as those on cultures containing100% nitrogen (1 mM NH4NO3) without inoculation. Inoculationof rice culture with Azospirillum is expected to reducenitrogen application on rice IR64 by the IAA production asindicated by significant changes in the root growth anddevelopment. A higher concentrations of IAA tend to givebetter effects on the root growth and development of riceIR64

Species and Functional Diversity of Rhizobacteria of Rice Plant in the Coastal Soils of Indonesia

Rhizobacteria are important components of soil and directly or indirectly influence the soils quality and plant growth for maintaining adequate plant nutrition and reducing the negative environmental effects of fertilizers. Applying high dose of chemical fertilizers in most of rice fields in the coastal areas could reduce the quality of the soil in the long time. There are few studies addressed to verify the species and functional diversity of cultivable rhizobacteria associated with rice plant in the coastal soils. The objective of the study was to verify the species and functional diversity of rhizobacteria isolated from the coastal soils of two rice production areas of Subang and Indramayu, West Java. Special focus was given to verify phosphate solubilization, nitrogen fixation, IAA and cellulase production of the selected 78 strains of rice rhizobacteria isolated from the coastal paddy field, as well as taxonomical analyses based on 16S rRNA. The results showed that among 78 bacterial isolates from the coastal paddy field, mostly were belonging to the Firmicutes, most of them affiliated with genera Bacillus, 75 strains produced IAA, 32 strains fixed nitrogen, 37 strains solubilized phosphate and 33 strains produced cellulase. Several strains of the rhizobacteria were capable of producing plant growth promoting substances (PGPR), alone or in combination, such as IAA, fixing nitrogen, solubilizing phosphate, and producing cellulase. Taking all of these diverse PGPR characteristics into account, it is clear that the 78 identified isolates have great potential for improving saline soils of the coastal paddy fields in Indonesia

Species and Functional Diversity of Rhizobacteria of Rice Plant in the Coastal Soils of Indonesia

Rhizobacteria are important components of soil and directly or indirectly influence the soils quality and plant growth for maintaining adequate plant nutrition and reducing the negative environmental effects of fertilizers. Applying high dose of chemical fertilizers in most of rice fields in the coastal areas could reduce the quality of the soil in the long time. There are few studies addressed to verify the species and functional diversity of cultivable rhizobacteria associated with rice plant in the coastal soils. The objective of the study was to verify the species and functional diversity of rhizobacteria isolated from the coastal soils of two rice production areas of Subang and Indramayu, West Java. Special focus was given to verify phosphate solubilization, nitrogen fixation, IAA and cellulase production of the selected 78 strains of rice rhizobacteria isolated from the coastal paddy field, as well as taxonomical analyses based on 16S rRNA. The results showed that among 78 bacterial isolates from the coastal paddy field, mostly were belonging to the Firmicutes, most of them affiliated with genera Bacillus, 75 strains produced IAA, 32 strains fixed nitrogen, 37 strains solubilized phosphate and 33 strains produced cellulase. Several strains of the rhizobacteria were capable of producing plant growth promoting substances (PGPR), alone or in combination, such as IAA, fixing nitrogen, solubilizing phosphate, and producing cellulase. Taking all of these diverse PGPR characteristics into account, it is clear that the 78 identified isolates have great potential for improving saline soils of the coastal paddy fields in Indonesia