Nitrogen bioavailability

Gillor, O. Harush, A. Hadas, O. Post, A. R Belkin, S. A Synechococcus PglnA,, luxAB fusion for estimation of nitrogen bioavailability to freshwater cyanobacteria, Appl Environ. Microbiol, Mdi. 2003, 69(3), 1465-1474. 

Bloremedia.tlon. Cmde oil and refined products are readily biodegradable under aerobic conditions, but they are only incomplete foods siace they lack any significant nitrogen, phosphoms, and essential trace elements. Bioremediation strategies for removing large quantities of hydrocarbon must therefore iaclude the addition of fertilisers to provide these elements la a bioavailable form. 

Sigman et al. [134] have pointed out that nitrate is the predominant form of bioavailable (or fixed ) nitrogen in the ocean, and the natural isotopic... 

The presence of suspended solid materials increases the extent of LAS biodegradation [13,28], but the rate of the process remains invariable. The influence of the particulate material is due specifically to the increased density of the microbiota associated with sediments. However, suspended solids may also reduce the bioavailability of IAS as a result of its sorption onto preferential sites (e.g. clays, humic acids), although this is a secondary effect due to the reversibility of the sorption process. Salinity does not affect IAS degradation directly, but could also reduce LAS bioavailability by reducing the solubility of this molecule [5], Another relevant factor to be taken into account is that biodegradation processes in the marine environment could be limited by the concentration of nutrients, especially of phosphorus and nitrogen [34],... 

Indeed, the choice of a nitrogen compound to be used as carrier in such O-alkyl prodrugs is not restricted to benzamides. Other amides were examined, e.g., phthalimide, succinimide, and saccharin. Thus, the saccharin prodrug of estradiol (11.50, R = 17/J-estradiol) underwent rapid nonenzymatic hydrolysis in rat and human plasma [85]. Administration of the prodrug to rats led to an impressive fivefold increase in the oral bioavailability of estradiol, and it was approximately nine times more potent orally, based on the 50% effective dose. 

Melphalan (Alkeran) is an amino acid derivative of mechlorethamine that possesses the same general spectrum of antitumor activity as do the other nitrogen mustards. However, the bioavailability of the oral preparation is quite variable (25-90%) from one patient to another. 

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