Stem , disruption

It is clear that such a manipulation of an RNA structure in GA is equivalent to climbing some energy barrier due to stem disruption, followed by descending to a (probably new) local minimum of free energy determined by stem formation. Repeated GA mutations represent a walk in a free energy landscape for a given sequence, that is, RNA folding pathway (44). As mentioned in the first section, the... 

Coumarin, the lactone of o-hydroxycinnamic acid, and some of its derivatives have been isolated from many plant species 31). Thimann and Bonner 141) attributed the growth-inhibiting effects of coumarin to its action on enzyme sulfhydryl groups. Inhibitory effects of coumarin on Avena coleoptiles and pea stem sections could be overcome by 2,3-dimercaptopropanol (BAL). Coumarin has also been reported to disrupt mitosis 29,30). 

Renal osteodystrophy stems from disruptions in calcium, phosphorus, and vitamin D homeostasis through the interaction with the parathyroid hormone. 

Levesque JP, Hendy J, Takamatsu Y, Simmons PJ, Bendall LJ. Disruption of the CXCR4/CXCL12 chemotactic interaction during hematopoietic stem cell mobilization induced by GCSF or cyclophosphamide. J Clin Invest 2003 111(2) 187-196. 

Inhibition of monoamine oxidase has been proposed as a possible mechanism underlying the hydrogen sulfide-mediated disruption of neurotransmission in brain stem nuclei controlling respiration (Warenycia et al. 1989a). Administration of sodium hydrosulfide, an alkali salt of hydrogen sulfide, has been shown to increase brain catecholamine and serotonin levels in rats. It has also been suggested that persulfide formation resulting from sulfide interaction with tissue cystine and cystinyl peptides may underlie some... 

The weak interactions that may exist between group 2 cations and anionic hydrocabyl ligands are demonstrated in the metal-in-a-box compounds such as [M(THF)6][Me3Si(fluorenyl)]2 (M = Ca 159 or Mg), which are formed by the addition of THF to solutions of the bis(fluorenyl) complexes in non-polar solvents. The box may be completed by the presence of aromatic molecules, as in 159 (Figure 84). The disruption of the metal-carbon bonds is thought to stem from a combination of robust M-THF interaction, the stability of the free [Me3Si(fluorcnyl)] ion, and the formation of numerous C-H- -7r interactions between THF and the anions. These and related examples are reviewed elsewhere. 

Ocular Effects. Vision was blurred in 15 of the 23 workers examined as a result of intermediate-or chronic-duration inhalation exposures to high blood concentrations (in excess of 2 pg/L) of chlordecone during its production. The effects on vision were characterized by a disruption of ocular motility following a horizontal saccade by rapid random multidirectional eye movements. Visual acuity and smooth eye movements were unaffected (Taylor 1982, 1985). The rapid eye movements were probably due to disturbance of the brain stem. 

Due to the specificity of toxicogenomic signatures, compounds may be classified based on common genes (or pathways) disrupted. In developmental toxicity testing, approaches may be used for classification between (1) toxic and nontoxic exposures and/or (2) classes of chemical compounds. To date, most classification studies have been conducted in alternative developmental systems (i.e. stem cells, zebrafish, whole embryo culture) due to the size of material and experimental groups needed. In a series of studies by... 

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