System mediated

The pathogenicity of Erwinia chrysanthemi 3937 on African violets involves at least five pectate lyases (PelA to PelE), one methyl pectin esterase (Pern), encoded by pelA to pelE, pern genes and an iron assimilation system mediated by chiysobactin [1], (Fig. 1). 

Hll. Haglund, U Systemic mediators released from the gut in critical illness. Crit. Care Med. 21, S15-S18 (1993). 

Pregnant women, infants and children face unique and possibly significant developmental and endocrine-system mediated risks from low-level pesticide exposure during critical windows of development, some with serious life-long consequences. 

Levels of folate in both the blood and the cerebrospinal fluid have been very low. The anemia is correctable with injections of folate, or with the administration of large oral doses, but the concentration in the CSF is still low, suggesting that a distinct carrier system mediates folate uptake into the brain and that this system is the same as that facilitating intestinal transport. 

Yaksh, T. L., and Wilson, P. R. (1979) Spinal serotonin terminal system mediates antinociception. J. Pharmacol. Exp. Ther., 208 446-453. 

The balance of opposing pro- and anti-platelet forces determines the overall hemostatic response. Successful hemostasis is achieved when assorted signal-transduction systems, mediators, white blood cells, and platelet receptors for agonists and adhesion molecules overcome the local resistance against platelet activation to generate... 

Which olfactory system mediates sexual behavior in mice has also been a matter of debate. Early studies (Thompson and Edwards 1972 Edwards and Burge 1973) suggested a role for the main olfactory system in the display of female sexual receptivity, since destructions of the MOE by intranasal infusion with a zinc sulfate solution (ZnS04) attenuated lordosis behavior in estrogen-progesterone-treated mice. However, the VNO may be also involved as a reduction in female sexual receptivity by VNO removal has been reported in various other rodent species (rats Rajendren,... 

Swann, Rahaman, F., Bijak, T. and Fiber, J. (2001) The main olfactory system mediates pheromone-induced fos expression in the extended amygdala and preoptic area of the male Syrian hamster. Neuroscience 105, 695-706. 

The correlation shown in Figure 7.4 would not be expected to hold for PAHs, when using linlish as a test species. This observation is based on the much higher levels of cytochrome P 50 dependent enzymes in linlish than in shellfish (Buhler and Williams, 1989). The P-450 system mediates Phase 1 metabolism of PAHs, which in this case consists of enzyme-catalyzed oxidation of the non-polar parent PAH molecule. 

Lenz, O. and Friedrich, B. (1998) A novel multicomponent regulatory system mediates H2 sensing in Alcaligenes eutrophus. Proc. Natl. Acad. Sci. USA, 95, 12474-9. 

Capuano CA, Leibowitz SF, Barr GA. 1992. The pharmaco-ontogeny of the paraventricular alpha 2-noradrenergic receptor system mediating norepinephrine-induced feeding in the rat. Brain Res Dev Brain Res 68(1) 67-74. 

Disorders of nervous system mediator release may be caused by aspartame, monosodium glutamate (MSG) ( Chinese restaurant syndrome , Hot-dog headache, or glutamate-induced asthma), and sulphites found in dried fruit, vegetables, pickled vegetables, and fruit juices. 

Overall, the central dopaminergic systems mediating reward appear to be more active in females than males, notwithstanding the fact that there may be exceptions under some conditions. 

Luckenbach T, Epel D (2005) Nitromusk and polycyclic musk compounds as long-term inhibitors of cellular xenobiotic defense systems mediated by multidrug transporters. Environ Health Perspect 113 17-24... 

The main olfactory system mediates munerous behaviors that will be discussed in the section on signaling and priming pheromones, and also... 

In the golden hamster, the VNO is essential for certain reproductive behaviors, while the main olfactory system mediates responses that involve species recognition (Johnston, 1992 Table 5.2). As in mice, removal of the VNO impairs sexual behavior in male golden hamsters, but only if carried out before the animal had had sexual experience (Meredith, 1986). The same is true for ultrasonic vocalizations. 

An additional condition may be imposed, even when a cofactor-independent enzyme is used, if a mediator molecule is involved in the electron transfer process, as is often the case with oxidases. Laccases, for example, may employ small-molecule diffusible mediator compounds in their redox cycle to shuttle electrons between the redox center of the enzyme and the substrate or electrode (Scheme 3.1) [1, 2]. Similarly, certain dehydrogenases utiHze pyrroloquinoline quinone. In biocatalytic systems, mediators based on metal complexes are often used. 

Shalitin D, Yang H, Mockler TC et al 2002 Regulation of A rahidopsis cryptochrome 2 by blue-light-dependent phosphorylation. Nature 417 763—767 Stanewsky R, Kaneko M, Emery P et al 1998 The cryb mutation identifies cryptochrome as a circadian photoreceptor in Drosophila. Cell 95 681-692 Takahashi JS, DeCoursey PJ, Bauman L, Menaker M 1984 Spectral sensitivity of a novel photoreceptive system mediating entrainment of mammalian circadian rhythms. Nature 308 186-188... 

Chapter 28). Stimulation of nicotinic receptors in adrenergic nerve terminals leads to the release of norepinephrine and activation of nicotinic chemoreceptors in the aortic arch and carotid bodies causes nausea and vomiting. Nicotinic receptors in the central nervous system mediate a complex range of excitatory and inhibitory effects. 

Caldji, C., Tannenbaum, B., Sharma, S., Francis, D., Plotsky, P.M., and Meaney, M.J. (1998) Maternal care during infancy regulates the development of neural systems mediating the expression of fearfulness in the rat. Proc Natl Acad Sci USA 95 5335-5340. 

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