Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics
The search for antibiotic compounds from the natural environment has been going on for seven decades, ever since penicillin entered the market and antibiotic treatments became routine. The evolutionary pressure put on the pathogenic microorganisms induced a rapid spreading of naturally occurring res...
| Main Author: | |
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| Format: | M2 |
| Language: | Inglés Swedish |
| Published: |
SLU/Dept. of Microbiology
2013
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| Subjects: |
| _version_ | 1855570916901126144 |
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| author | Lilja, Tua |
| author_browse | Lilja, Tua |
| author_facet | Lilja, Tua |
| author_sort | Lilja, Tua |
| collection | Epsilon Archive for Student Projects |
| description | The search for antibiotic compounds from the natural environment has been going on for seven decades, ever since penicillin entered the market and antibiotic treatments became routine. The evolutionary pressure put on the pathogenic microorganisms induced a rapid spreading of naturally occurring resistance genes, leaving only the option of finding new antibiotics to treat the resistant pathogens. Microorganisms have been extensively mined for their biosynthetic abilities to produce biologically active compounds. To date, more than 23 000 microbial natural products have been discovered. The Actinomycetales are ubiquitous bacteria that have been used for antibiotic discovery for more than half a century, and over 10 000 natural products have been identified from the order. The genus of Streptomyces is acknowledged as the most prolific producer of natural products, but lately, non-Streptomyces species have been on the rise in novel drug research. Mainly terrestrial species have been studied, but the marine environment offer just as much, if not more, biodiversity to mine for new natural products. In this study, five marine and marine-associated samples were collected from south Shetland archipelago and southern Sweden coastal areas. The samples were subjected to seven selective treatments of varying chemical or physical nature. The samples were subsequently incubated on one general and six selective agar media of varying compositions of nutrients to enrich mainly for bacteria of more advanced metabolic capacity. Bacterial isolates (340 and counting) were recovered from the cultures, and the 16S rDNA of 96 strains was sequenced. A phylogenetic tree analysis of 91 sequences identified to the genus or species level was carried out. Biological assays were carried out on a few selected isolates, and their antibiotic potential was assessed. One strain analyzed by HPLC was found to produce the known antibiotic compound oxydifficidin. |
| format | M2 |
| id | RepoSLU5869 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2013 |
| publishDateSort | 2013 |
| publisher | SLU/Dept. of Microbiology |
| publisherStr | SLU/Dept. of Microbiology |
| record_format | eprints |
| spelling | RepoSLU58692013-07-10T10:36:39Z Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics Lilja, Tua antibiotics natural products marine microorganisms isolation methods actinomycetes rare actinomycetes whole-cell screening antimicrobials antibiotic resistance The search for antibiotic compounds from the natural environment has been going on for seven decades, ever since penicillin entered the market and antibiotic treatments became routine. The evolutionary pressure put on the pathogenic microorganisms induced a rapid spreading of naturally occurring resistance genes, leaving only the option of finding new antibiotics to treat the resistant pathogens. Microorganisms have been extensively mined for their biosynthetic abilities to produce biologically active compounds. To date, more than 23 000 microbial natural products have been discovered. The Actinomycetales are ubiquitous bacteria that have been used for antibiotic discovery for more than half a century, and over 10 000 natural products have been identified from the order. The genus of Streptomyces is acknowledged as the most prolific producer of natural products, but lately, non-Streptomyces species have been on the rise in novel drug research. Mainly terrestrial species have been studied, but the marine environment offer just as much, if not more, biodiversity to mine for new natural products. In this study, five marine and marine-associated samples were collected from south Shetland archipelago and southern Sweden coastal areas. The samples were subjected to seven selective treatments of varying chemical or physical nature. The samples were subsequently incubated on one general and six selective agar media of varying compositions of nutrients to enrich mainly for bacteria of more advanced metabolic capacity. Bacterial isolates (340 and counting) were recovered from the cultures, and the 16S rDNA of 96 strains was sequenced. A phylogenetic tree analysis of 91 sequences identified to the genus or species level was carried out. Biological assays were carried out on a few selected isolates, and their antibiotic potential was assessed. One strain analyzed by HPLC was found to produce the known antibiotic compound oxydifficidin. POPULÄRVETENSKAPLIG SAMMANFATTNING Antibiotika är ett av de viktigaste medel vi har för att bekämpa infektioner. Tyvärr har våra möjligheter att använda olika antibiotika kraftigt begränsats på grund av att mikroorganismerna har utvecklat olika resistensmekanismer vilka också sprids mellan olika arter. Resistensspridningen är i dag ett globalt problem vilket lett till att man inom forskningen aktivt försöker hitta nya typer av antibiotika. Om nya mediciner och behandlingar mot infektioner inte upptäcks och utvecklas riskerar mänskligheten att klockan vrids tillbaka till den pre-antibiotiska eran och att enkla infektioner därmed kan bli livshotande. Nya antibiotika kan upptäckas och vidareutvecklas med hjälp av flera metoder. Den vanligaste och äldsta metoden är att leta i naturen efter mikroorganismer som uppvisar en hämmande aktivitet mot andra mikroorganismer. En alternativ metod är att modifiera existerande antibiotika på kemisk väg, och på så sätt skapa olika versioner av en och samma substans. Ofta används en kombination av båda metoderna, där man först hittar en naturlig substans som man sedan kan modifiera. Metoden att leta efter mikroorganismer i naturen har hittills lett till upptäckten av 23 000 aktiva molekyler, och då inte bara antibiotika, utan också antivirala läkemedel, anti-cancerläkemedel, insektsmedel, industriella enzymer, etc. Av dessa 23 000 substanser kommer cirka 10 000 från en speciell bakteriegrupp som kallas aktinomyceter. Aktinomyceter är bakterier som lever naturligt i alla miljöer över hela världen. De är ekonomiskt betydelsefulla eftersom de är exceptionellt duktiga på att producera molekyler som kan användas inom medicin, industri, och jordbruk. Jämfört med andra vanligt förekommande bakterier är aktinomyceter mycket komplexa, med en avancerad ämnesomsättning som gör dem till troliga producenter av ovanliga ämnen som ofta kan komma till användning. Dessa bakterier beräknas kunna producera hundra tusen olika sorters substanser vilket är en av anledningarna till att man aktivt letar efter nya arter av aktinomyceter Den mest lovande miljön att undersöka idag är haven; de är de största ekosystemen som finns på planeten, och de minst utforskade. Forskare letar efter nya bakteriearter i allt från uråldriga glaciärer till heta undervattenskällor i havsbotten, och nya mikroorganismer upptäcks därför ideligen. I det här forskningsprojektet analyserades sammantaget fem olika prover från fyra platser i två världsdelar: Whaler’s Bay på Deception Island och Yankee Harbour på Greenwich Island (Antarktis) samt från Mollösund i Skagerak och Torekov i Skälderviken (Sverige). Proven behandlades enligt sju olika kemiska och fysiska metoder och bakterier från proven odlades sedan upp på agarplattor med varierande typer och mängd av näringsämnen. Intressanta bakteriekolonier isolerades, och genom att sekvensera valda delar av bakteriernas DNA kunde de sorteras in i grupper av redan kända bakterier på släkt- eller artnivå. Över 300 bakterieisolat har tagits till vara och nära 100 av dessa har identifierats med hjälp av DNA-sekvensering. Vissa bakterieisolat testades även för antibiotisk aktivitet mot mikroorganismer som är sjukdomsframkallande hos människor. Hos ett isolat hittades flera aktiva substanser, varav en kunde identifieras som oxydifficidin, vilket är en tidigare känd antimikrobiell substans. SLU/Dept. of Microbiology 2013 M2 eng swe https://stud.epsilon.slu.se/5869/ |
| spellingShingle | antibiotics natural products marine microorganisms isolation methods actinomycetes rare actinomycetes whole-cell screening antimicrobials antibiotic resistance Lilja, Tua Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title | Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title_full | Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title_fullStr | Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title_full_unstemmed | Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title_short | Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| title_sort | isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics |
| topic | antibiotics natural products marine microorganisms isolation methods actinomycetes rare actinomycetes whole-cell screening antimicrobials antibiotic resistance |