Actinomycetes from Sediments in the Trondheim Fjord, Norway: Diversity and Biological Activity

Abstract

Abstract:The marine environment represents a largely untapped source for isolation of new microorganisms with potential to produce biologically active secondary metabolites. Among such microorganisms, Gram-positive actinomycete bacteria are of special interest, since they are known to produce chemically diverse compounds with a wide range of biological activities. We have set out to isolate and characterize actinomycete bacteria from the sediments in one of the largest Norwegian fjords, the Trondheim fjord, with respect to diversity and antibiotic-producing potential. Approximately 3,200 actinomycete bacteria were isolated using four different agar media from the sediment samples collected at different locations and depths (4.5 to 450 m). Grouping of the isolates first according to the morphology followed by characterization of isolates chosen as group representatives by molecular taxonomy revealed that Micromonospora was the dominating actinomycete genus isolated from the sediments. The deep water sediments contained a higher relative amount of Micromonospora compared to the shallow water samples. Nine percent of the isolates clearly required sea water for normal growth, suggesting that these strains represent obligate marine organisms. Extensive screening of the extracts from all collected isolates for antibacterial and antifungal activities revealed strong antibiotic-producing potential among them. The latter implies that actinomycetes from marine sediments in Norwegian fjords can be potential sources for the discovery of novel anti-infective agents.

Analysis of Antarctic proteobacteria by PCR fingerprinting and screening for antimicrobial secondary metabolites

“…This phenomenon has resulted in similar or identical finding of compounds from well-known bacteria even though they were isolated from different environments (Bredholt et al, 2008). The reduction of new metabolites discovered has forced the search into new habitats.…”

“…Recently, more global findings have shown that novel bacteria from various extreme or poorly explored environments are capable of producing valuable sources of new bioactive metabolites and compounds (Bredholt et al, 2008;Rojas et al, 2009). Therefore, it is important to determine the taxonomic relationships and metabolic diversity of bacteria.…”

“…For many years, the drugs used successfully to treat various diseases were bacterium-derived compounds (Aislabie et al, 2008). Recently, due to the possible frequent genetic exchange between species (Bredholt et al, 2008), the chances of novel discovery of bioactive molecules from various well-known bacteria seem to have fallen dramatically. For example, the isolation of highly bioactive Streptomyces from different environments still produces similar metabolites or compounds.…”

Anti-Microbial Properties of Secondary Metabolites of Marine Gordonia tearrae Extract

“…They also serve as alternative sources of biologically active substances (Behal, 2003) especially in combating infectious diseases which today are leading health problems with high morbidity and mortality in the developing countries (Black et al, 1982). Several reports are available on antibacterial and antifungal activity of marine actinomycetes (Suthindhiran & Kannabiran, 2009;Bredholt et al, 2008) but relatively few studies are available for Gordonia species. Gordonia tearrae is one of 27 Gordonia species of marine actinomycetes (Arenskotter et al, 2004).…”

Diacidene, a Polyene Dicarboxylic Acid from a Micromonospora Isolate from the German Wadden Sea

“…Marine sediments have proven a profi table habitat for the isolation of high numbers of Micromonosporaceae (Bredholt et al, 2008;Maldonado et al, 2008;Prieto-Davó et al, 2008). Our isolate, Micromonospora strain DB620, originated from the German Wadden Sea, a unique ecosystem characterized by large areas of tidal fl ats.…”