Screening for antimicrobial activities of bacteria from Antarctica
Naturally produced antimicrobial agent or antibiotics is a low molecular weight natural substance produced by microorganism to inhibit the growth of or kill other microorganisms. Antibiotics from microbes have been used to develop drugs to combat various pathogens. Nevertheless many pathogens hav...
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| Format: | Academic Exercise |
| Language: | English |
| Published: |
2008
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| Online Access: | https://eprints.ums.edu.my/id/eprint/20519/1/Screening%20for%20antimicrobial.pdf https://eprints.ums.edu.my/id/eprint/20519/ |
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| Summary: | Naturally produced antimicrobial agent or antibiotics is a low molecular weight natural
substance produced by microorganism to inhibit the growth of or kill other
microorganisms. Antibiotics from microbes have been used to develop drugs to combat
various pathogens. Nevertheless many pathogens have developed resistance to the
existing antibiotics. Additionally, the pipeline of new drugs is running dry and the
incentives to develop new antimicrobials to address the global problems of drug
resistance are required. Hence the aims of this study were to isolate and characterize
bacteria which produce antimicrobial agent. Bacteria from soil sample in Antarctica were
screened for antimicrobial activities by using Escherichia coli 0157: H7, Klebsiella
pneumoniae 14x and Salmonella typhimurium (S. Tm 13) as tester strains. Two out of the
356 bacterial isolates exhibited antagonistic effect on the tester strains which were then
labeled as SS157 and SR13. Characterization of both strains indicated that their optimal
growth temperature was 20°C, salt tolerance up to 3% (w/v) and an optimal growth at pH
7. SR13 was found to be Gram positive rods while Gram stain of SS157 shows that it is a
Gram negative coccus. Biochemical tests performed revealed common significant taxa
for both as Pseudomonas fluorescens with a percentage identity up to 99.9%. These were
then further identified based on their 16S rDNA gene sequences. The 16S rDNA gene
was partially sequenced and sequences with length of 1531 and 1536 base pair were
obtained for SS157 and SR13 respectively. BLASTn search results revealed that SS157
bears a close phylogenetic relationship to Pseudomonas congelans DSM 14939T( -99%)
while SRI 3 was found to bear a close phylogenetic relationship to Pseudomonas tremae CFBP 6111T (-98%). |
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