Axenic

Axenic Literally "without strangers." A system in which all biological populations are defined, such as a pure culture. 

Algal blooms in fresh water ponds occasionally poison livestock and waterfowl. Axenic cultures of Anabaena flos-aquae NRC 44-1 were shown to produce the toxic principle (5) which can be present in the algae and in the water of mature cultures (6). The discovery of the toxin was fortuitous in the sense that AChR agonists do not have a (known) constructive function in the algae evolution of the synthetic pathway was likely a by-product of metabolic pathways in the algae. The compound became evident only through its toxic effects on other organisms. 

Trinitrotoluene (TNT) is reduced by the aquatic plant Myriophyllum spicatum to ami-nodinitrotoluenes (Pavlostathis et al. 1998) and, in axenic root cultures of Catharanthus roseus, the initial metabolites 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dintrotoluene... 

Bhadra R, DG Wayment, JB Hughes, V Shanks (1999) Confirmation of conjugation processes during TNT metabolism by axenic plant roots. Environ Sci Technol 33 446-452. 

Gao J, AW Garrison, C Hoehamer, CS Mazur, NL Wolfe (2000) Uptake and phytotransformation of o./j -DDX andp,p -DDT by axenically cultivated aquatic plants. 7 Agnc Eood Chem 48 6121-6127. 

Mobilization of inicronutrients such as Zn, Mn, Cu, and Co and of heavy metals (Cd, Ni) in soil extraction experiments with root exudates isolated from various axenically grown plants is well documented (61,204-206) and has been related to the presence of complexing agents. 

G. Costa, J. C. Michaut, and A. Guckert, Amino acids exuded from axenic roots of lettuce and white lupin seedlings exposed to different cadmium concentrations. J. Plant Nutr. 20 883 (1997). 

R. L. Rittenhouse and M. G. Hale, Loss of organic compounds from roots. II. Effect of O, and CO, tension on release of sugars from peanut roots under axenic conditions. Plant Soil. 15 311 (1971). 

D. Vaughan and D. J. Linehan, The growth of wheat plants in humic acid solutions under axenic conditions. Plant Soil 44 445 (1976). 

J. A. Trofymow, D. C. Coleman, and C. Cambardella, Rates of rhizodeposition and ammonium depletion in the rhizosphere of axenic oat roots. Plant Soil 97 333 (1987). 

The use of microbial siderophores by dicotyledonous plants appears to involve uptake of the entire metallated chelate (42-44), or an indirect process in which the siderophore undergoes degradation to release iron (45). As demonstrated in initial studies examining this question, there was concern that iron uptake from microbial siderophores may be an artifact of microbial iron uptake in which radiolabeled iron is accumulated by root-colonizing microorganisms (46). Consequently, evidence for direct uptake of iron from microbial siderophores has required the use of axenic plants. In experiments with cucumber, it was shown that the microbial siderophore ferrioxamine B could be used as an iron source at concentrations as low as 5 pM and that the siderophore itself entered the plant (42). 

Y. Wang, H. N. Brown, D. E. Crowley, and P. J. Szaniszlo, Evidence for direct utilization of a siderophore, ferrioxamine B in axenically grown cucumber Plant Cell Environ. 76 579 (1993). 

A. Chaboud and M. Rougier, Effect of root density in incubation medium on root exudate composition of axenic maize seedlings, J. Plant Physiol. 131 602 (1991). 

Axenic cultures of dwarf spikerush (Eleocharis colorado-ensis) were established in 4 L aspirator bottles containing quartz sand and a synthetic culture medium. These were periodically drained and the effluent subjected to fractionation and bioassays. This crude leachate was passed through a C. cartridge to separate polar from nonpolar compounds. The nonpolar fraction was eluted from the cartridge with acetone and the solvent evaporated with gas. The polar fraction was lyophilized. Both... 

Table IV. Effects of 250 Nonpolar Peaks from Axenic ppmw Murashige and Skoog Cultures of Spikerush on Root Growth Medium, Polar and Lettuce Seedling...

Ronkko, R. Pennanen, T. Smolander, A. Kitunen, V. Kortemaa, H. Haahtela, K. Quantification of Frankia strains and other root-associated bacteria in pure cultures and in the rhizosphere of axenic seedlings by high-performance liquid chromatography-based muramic acid assay. Appl. Environ. Microbiol. 1994, 60, 3672-3678. 

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