Journal of Infectious Diseases & Preventive Medicine
Open Access
ISSN: 2329-8731
ISSN: 2329-8731
Abdolkader Abosamaha,
Sebha University, Libya
Scientific Tracks Abstracts: J Infect Dis Preve Med
Compatible solutes, and the organisms that produce them, have attracted considerable interest in recent years. Ectoine and hydroxyectoine are of particular interest, because they have particularly powerful effects in stabilizing cells and biomolecules. They have applications in stabilizing cells against stress and are used widely in skin care, with sales estimated at 15000 tonnes per annum, generating a market of tens of millions of US dollars per year. They have also been proposed to be useful for treatment of eye irritation, allergic rhinitis and Alzheimer’s disease. Hydroxyectoine appears to have a specific role in heat stress protection. Of particular promise is the observation that ectoine and hydroxyectoine are more effective excipients for stabilizing antibodies than trehalose, which promises wide application in pharmaceutical production. There is thus considerable interest in new routes for commercial production ofthese compatible solutes. Four Gram-negative bacterial strains, belonging to the family Halomonadaceae, were isolated from Qaberoun and Um-Alma lakes in South Libya using high-salinity medium. The strains were identified using 16S rRNA gene sequencing as belonging to Halomonas pacifica (strain ABQ1), Halomonas venusta (ABQ2), Halomonas elongata (ABU1) and Halomonas salifodinae (ABU2). H. pacifica ABQ1 is a moderate halophile (salinity range 0.05 to 2.5 M NaCl), with a broad tolerance to pH (7 to 9) and temperature (25–37 C). Addition of the compatible solutes glycine betaine (betaine) and ectoine (1,4,5,6-tetrahydro-2-methyl-4- pyrimidinecarboxylic acid) to the medium had a positive effect on growth of H. pacifica at 2 M NaCl. In rich LB medium, betaine was the major compatible solute accumulated, with ectoine only being accumulated at salinities in excess of 1 M NaCl. In minimal M9 medium, betaine was not produced, but increasing amounts of ectoine were synthesized with increasing salinity, and hydroxyectoine [(4S,5S)−5-hydroxy- 2- methyl- 1,4,5,6- tetrahydropyrimidine- 4- carboxylic acid] was also synthesized when the cells were grown in very high salt. We have thus identified H. pacifica as a producer of ectoine and hydroxyectoine, with more being produced at higher salinities. As industrial demand for these compatible solutes continues to increase, this system has biotechnological potential.
Dr Abdolkader has carried out his experiments on halophilic bacteria in highly saline lakes in the Sahara of south west Libya. He looked at the accumulation of compatible solutes in the bacteria cell as one of the most strategies used by halophilic organism to tolerate surviving in extreme environment.