Marine heterotrophic bacteria

Structures of siderophores synthesized by marine heterotrophic bacteria (a) aquacheiins from Halomonas aquamahna, (b) iron binding to muitipie oxygen atoms in an aquacheiin,... 

Barbeau K, Rue EL, Trick CG, Bruland KW, Butler A (2003) Photochemical Reactivity of Siderophores Produced by Marine Heterotrophic Bacteria and Cyanobacteria Based on Characteristic Fe(III) Binding Groups. Lirrmol Oceanogr 48 1069... 

Kirchman, D. L. 2000. Uptake and regeneration of inorganic nutrients by marine heterotrophic bacteria. In Microbial Ecology of the Oceans (D. L. Kirchman, Ed.), pp. 261-288. Wiley-Liss, New York. 

Barbeau, K., Rue, E. L., Trick, C. G., Bruland, K. T., and Butler, A. (2003). Photochemical reactivity of siderophores produced by marine heterotrophic bacteria and cyanobacteria based on characteristic Fe(III) binding groups. Limnol. Oceanogr. 48, 1069-1078. 

Figure 6 Two examples of ampiphilic siderophores produced by marine heterotrophic bacteria (after Martinez et al, 2000).

Kjellberg S, M Hermansson, P Marden, GW Jones (1987) The transient phase between growth and nongrowth of heterotrophic bacteria with emphasis on the marine environment. Annu Rev Microbiol 41 25-49. Klump H, J Di Ruggiero, M Kessel, J-B Park, MWW Adams, FT Robb (1992) Glutamate dehydrogenase from the hyperthermophile Pyrococcus furiosus. Thermal denaturation and activation. J Biol Chem 267 22681-22685. 

In addition to serving as the major food source to heterotrophic bacteria, DOM plays an important ecological role in enabling marine organisms to control various aspects of their environment including trophic interrelationships. This is accomplished by the secretion or exudation of specific molecules, called secondary metabolites. These are generally LMW compounds that tend to be species specific in their source and targets. Some act as toxins that repel or kill competitors or predators. As noted earlier, some diatoms... 

Heterotrophic bacteria have the ability to incorporate not only inorganic N but also dissolved inorganic P into organic material. Additionally, as microbes have extremely high P content relative to plants or even phytoplankton (Kirchman, 1994), HOP may be expected to be at least as or even more important than HON. Studies in lakes and marine systems support the importance of HOP in forming new organic P in aquatic systems (Kirchman, 1994). 

Middleburg, J. J., and J. Nieuwenhuize. 2000b. Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate rich Thames Estuary. Marine Ecology Progress Series 203 13-21. 

Martinussen, I., and T. F. Thingstad. 1987. Utilization of N, P, and organic C by heterotrophic bacteria. II. Comparison of experiments and a mathematical model. Marine Ecology... 

Phosphate transporters have been characterized in many model organisms, though relatively little mechanistic work has been done in marine phytoplankton. Phosphate transport is elfected by high and low affinity transporters and dependent on ATP, Na, and Mg " " in several diatoms (Cembella et al., 1984). These observations are found to be consistent with the well known active transport system of yeast (Raghothama, 1999). The dependence of phosphate transport on Mg " " in diatoms and yeast suggests that eukaryotes may transport an uncharged cation phosphate complex (MeHP04, where Me may be Ca +, Mg +, Co +, Mn ) as has been observed in heterotrophic bacteria (van Veen, 1997). 

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