Lone Gram's web-page
Education and employment
Professor at the Department for Biotechnology and Biomedicine (previously Systems Biology) (2013-), Technical University of Denmark, at DTU National Food Institute (2010-2012), at DTU Aqua and DTU SystemBiology (2005-2010) and at the Danish Institute for Fisheries Research (2000-2005).
Received the Villum-Kann Rasmussen Annual Award (2016), the Fritz Kaufmann Mindefond award (2008) and Tagea Brandt travel award (2008)
Visiting research scientist in 2009 at Professor Roberto Kolter's group at Harvard Medical School, Boston, USA and in 1994-95 and 1999 at Professor Staffan Kjelleberg's group at University of New South Wales, Australia.
Chairman of the Danish Research Council for Natural Sciences (2015-), vice chair (2014) and member (2013-). Editor of Applied and Environmental Microbiology (2006-2012), member of the Danish Council for Research Policy (2007-2011)
External associate professor at the RVAU 1989-2000. Consultancies for the Food and Agricultural Organization of the United Nations (FAO) on projects and courses related to fish technology
Member (1998-2007) and secretary (2003-2007) of ICMSF; the International Commission on Microbiological Specifications for Foods (revised March 2007)
M.Sc. in food science (1980-1985) and Ph.D. (1989) from the Royal Veterinary and Agricultural University (RVAU)
In 2006, I joined a global scientific marin cruise (Galathea3) where we determined the distribution of culturable bacteria with antibacterial activity in the marine environment . Specifically, we have searched for organisms belonging to the Roseobacter clade but our work has also demonstrated that Pseudoalteromonas spp. and Vibrio spp. have inhibitory properties. This work can potentially be of interest in drug discovery work. A short Danish description of the project is available.
The research of my group aims at developing and using novel antibacterial principles to control pathogenic bacteria. We also assess impact and physiological effects on pathogenic bacteria of known and novel antibacterials. In part, novel antibacterials are derived from (marine) bacteria and we use bacteria with desired characteristics (probiotics, producers of bioactive compounds) in our quest to control bacteria that are pathogenic either to man or to fish. Below is brief list of topics and articles related to work in the group. You can find a description of the Bacterial Ecophysiology and Biotechnology Group.
Novel antibacterial compounds. We have a constant need for controlling unwanted bacteria - be it infectious or spoiling microorganisms. We spend a vast amount of our time removing or killing bacteria; washing, cleaning, disinfecting, in food preservation - and in treatment of infectious diseases. We have worked with a multitude of novel antibacterial compounds - bacteriocins, antimicrobial peptides, enzymes and compounds affecting quorum sensing. We are currently (2013) focusing on antibacterial compounds produced by marine bacteria and the use of antimicrobial peptides.
Fish probiotics and interactions between marine bacteria. An ever increasing amount of fish is being produced in aquaculture - today almost 50% of fish used for human consumption are farmed. Although vaccines have been tremendously succesful as disease control measures, antibiotics are still used against several bacterial fish diseases. Due to the concerns raised vis-a-vis development of antibiotic resistance, alternative disease control measures must be sought. Probiotics (live microbial cultures which when supplied to the host confers a beneficial effect) have, in some scenarios, been succesful. We are currently especially interested in the potential of marine Roseobacter as fish larval probiotics. We collaborate with German, Norwegian, Greek and American research groups on this organism
Listeria monocytogenes - ecology and virulence. Listeria monocytogenes is an important food-borne pathogen that, in high risk population groups, can cause the serious infectious disease, listeriosis. The disease is typically transmitted with ready-to-eat food products in which the organism has grown to high numbers. We study all aspects related to measures than can control the organism. This includes its prevalence in the environment, its persistance in food processing, its biofilm formation, prevention of growth using bioprotection - and recently also its interaction with eucaryotic cells and hosts. We have projects both at the very applied level - working with the fish processing industry - and at a more basic scientific level where we collaborate with several Danish and international research groups.
Hygiene and biofilms. In the environment most bacteria will grow adhered to surfaces and not as free living cells. The ability to grow at surfaces as biofilms is also important in food processing environments. We have studied the biofilm formation and the subsequent enzymatic removal of biofilms by several methods. These studies are continued in collaboration with several Danish research institutes and industries in which we study the adherence and biofilm formation of the food borne pathogen Listeria monocytogenes. We have, in model systems evaluated different surface modifications and have determined the effect of surface roughness (of stainless steel) on bacterial adhesion. On an industrial scale, we have compared different types of disinfection processes with respect to effect on hygienic level in general, on on Listeria monocytogenes. We have demonstrated that surface coatings (e.g. fish extracts) can be used to reduce bacterial adhesion withing interfering with growth of the bacterial cell. We collaborate with several Danish and international research groups.
Quorum related interactions between bacteria on fish and in fish products. Bacteria will through antagonistic and synergistic activities interact and influence the growth and metabolism of one another. Many pathogenic bacteria and symbiotic bacteria employ acylated homoserine lactones (AHLs) in cell-to-cell communication. This communication enables them to coordinate gene expression, e.g. toxin production, in a population. We have assessed the importance of AHL communication in food spoilage and the effect of specific quorum sensing inhibtiors (QSIs). We also study AHL-signalling in fish pathogenic bacteria and have demonstrated that compounds interfereing with AHL-systems (so-called quorum sensing inhibtors) reduce vibriosis mortality in rainbow trout. Studies on AHL signalling and QSI compounds were carried out in close collaboration with Professor Michael Givskov at KU-SUND and Dr. Kristian Fog Nielsen at Systems Biology at the Technical University of Denmark. Currently, we collaborate with the Feed Research Institute of the Chinese Academy of Agricultural Sciences on QS in fish pathogens and the potential use of QSIs.
Ecology and detection of Shewanella putrefaciens . The spoilage of aerobically stored iced fish is mainly caused by growth and metabolism of S. putrefaciens. We have used the spoilage reactions (e.g. reduction of trimethylamine oxide and production of H2S or antibody technology for specific detection of this organism. S. putrefaciens is able to use many compounds, including Fe3+, as electron acceptors. We have shown that during aerobic respiration, S. putrefaciens uses specific iron chelators, so-called siderophores, for iron uptake and that fish based substrates are well suited for detection of siderophore production by several bacteria. Many mesophilic strains formerly identified as S. putrefaciens belong to a different species, Shewanella algae which may cause wound infections and bacteremia in humans. S. algae is a marine bacterium and can be detected in Danish marine waters when the water temperature is above 15°C. Our work has, in collaboration with American collegues, led to the identification of several new Shewanella species