Medium deficiency

Label cellular proteins metabolically by incubating cultures for 4-24 h with 35S-methionine, 3H-lysine, or l4C-amino acids in medium deficient in the relevant amino acid. 

The discovery of Mo-independent nitrogenases is so recent that their contribution to the global cycling of N is unknown. There is good evidence that they are widely distributed in organisms other than in Azotobacter. Recently a nifHDK deletion strain of the photosynthetic bacteria Rhodobacter capsulatus was shown to grow on N2 in medium deficient in Mo and V. Nitrogenase with properties similar to the third... 

In acidic medium containing an excess of dithizone (formula 1.1), copper(II) forms the violet dithizonate, Cu(HDz)2, which is soluble in non-polar solvents (CCI4, CHCI3) [12,13]. In alkaline medium, the less-intensely coloured, yellow-brown cupric dithizonate is formed. It can also be formed in a neutral or acidic medium deficient in dithizone. 

Under the special growth conditions of intestinal epithelial Caco-2 cells, the transport of riboflavin via passive diffusion processes was reported (Middleton 1990 Zielihska-Dawidziak et al. 2008). When riboflavin was over-supplemented (the incubation was at a concentration higher than in human plasma, i.e. >12 nM), riboflavin uptake was signiflcantly decreased. Conversely, growth in medium deficient in vitamin B2 caused a significant increase in vitamin uptake. 

A number of species of bacteria when grown on a medium deficient in iron excrete relatively high levels of compounds containing the... 

Nicaud, J.-M., Belin, J.-M., Pagot, Y., and Endrizzi-Joran, A. (1996) Bio-conversion of substrate with microbe auxotrophic for compound in medium deficient in this compound. Patent FR 2734843. 

Cells of Paracoccus denitrificans grown in a complex medium deficient in divalent cations exhibited a higher ratio of ornithine-containing lipid to phospholipids than that observed in cells grown in the same medium supplemented with Mg " and Ca ". It has been suggested that the zwitterionic ornithine-containing lipid was less dependent than acidic phospholipids on divalent cations for their incorporation in the outer membrane (41). 

Wee, S., and B. J. Wilkinson Increased Outer Membrane Ornithine-Containing Lipid and Lysozyme Penetrability of Paracoccus denitrificans Grown in a Complex Medium Deficient in Divalent Cations. J. Bacteriol. 170, 3283 (1988). 

The part of thiamin in the nutrition of propionic acid bacteria was further illmninated by Wood, Andersen, and Werkman (435) and by Silverman and Werkman (346) who found it possible to train certain strains, which ori ally required the addition of thiamin, to dispense with this substance and to give vigorous and continued growth on a basal medium not containing it. Serial transfer in a medium deficient in thiamin was the method... 

The very appearance of figure lOJ-20 - and of the poster Biochemical Pathways as a whole [20] - clearly points out the deficiencies of a two-dimensional medium, a drawing plane, to represent the complexity, the high interconnectivity of biochemical pathways. 

The same is true of the thiazole acid 40. Although discovered as a growth factor, it is unable to sustain the growth of a thiazole-deficient mutant of E. coli in a liquid medium. It does not decarboxylate in water solution at pH 7. Phosphate 41 (Scheme 17) is also biologically inactive. In any case, if there is only one metabolic route to the thiazole of thiamine, the very structures of 39 and 40 show that they cannot both be intermediates. 

Na also appears to play a role in palytoxin action in some systems. To determine if there is a Na requirement for palytoxin action on the EGF receptor, Swiss 3T3 cells were assayed for palytoxin activity in Na containing medium versus Na deficient medium. When NaCl is replac by cholineCl, palytoxin can no longer inhibit EGF binding in Swiss 3T3 cells (Figure 5). By contrast, PDBu is equipotent in both Na containing and Na free media (data not shown). 

In recent years considerable attention has focused on the mechanisms of oxidative damage to the cornea. In a study to determine the interaction of ascorbate, hydrogen peroxide and oxygen in the eye, Riley et al. (1986) found that ascorbate promoted corneal swelling when isolated corneas were perfused with glucose-deficient medium. This was due to the rapid oxidation of... 

Despite increased citrate accumulation in roots of Zn-deficient rice plants, root exudation of citrate was not enhanced. However, in distinct adapted rice cultivars, enhanced release of citrate could be observed in the presence of high bicarbonate concentrations in the rooting medium, a stress factor, which is frequently associated with Fe and Zn deficiency in calcareous soils (235) (Hajibo-huid, unpublished). This bicarbonate-induced citrate exudation has been related to improved Zn acquisition in bicarbonate-tolerant and Zn-efficient rice genotypes (Fig. 9) (23S). Increased exudation of sugars, amino acids, and phenolic compounds in response to Zn deficiency has been reported for various dicotyledonous and monocotyledonous plant species and seems to be related to increased... 

V. D. Jolley and J. C. Brown, Soybean response to iron-deficiency stre.ss as related to iron supply in the growth medium. Journal of Plant Nutrition 10 631 (1987). 

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