Internalization pathway

The Shikimate pathway is responsible for biosynthesis of aromatic amino acids in bacteria, fungi and plants [28], and the absence of this pathway in mammals makes it an interesting target for designing novel antibiotics, fungicides and herbicides. After the production of chorismate the pathway branches and, via specific internal pathways, the chorismate intermediate is converted to the three aromatic amino acids, in addition to a number of other aromatic compounds [29], The enzyme chorismate mutase (CM) is a key enzyme responsible for the Claisen rearrangement of chorismate to prephenate (Scheme 1-1), the first step in the branch that ultimately leads to production of tyrosine and phenylalanine. 

While GPCR phosphorylation at serine and threonine residues is involved in the internalization pathways of many receptors (134,176-178), it is likely that for some GPCRs internalization pathways may be distinct (134,176-178). These apparently nonarrestin mechanisms of internalization, however, may vary more between receptors than those identified for GRK-dependent processes (179,180). 

Many cells, such as lymphocytes, do however lack efficient internalizing receptor systems. The development of a new and effective internalizing pathway thus appears as a very important goal. Weissleder et al. [83, 96] have tried to develop such a system by attaching a superparamagnetic iron oxide to a membrane translocating signal (MTS) peptide. Several MTSs have been described... 

Similar results were found by Komeda et al. [51] and Pascual et al. [43] for the diffusion CO and NH3 respectively. In both cases, molecular motion was activated by excitation of internal stretch modes. By modeling theoretically the coupling between internal and external modes, these works gave a magnitude for the relevance of such internal pathways compatible with experimentally measured reaction yields. 

Intermode coupling All of these experimental findings reveal the existence of internal pathways of energy transference between modes which eventually become efficient due to non-negiigible coupling between the excited internal mode and the mode directly actuating in the reaction coordinate. 

SRI International Pathway Tools software supports creation, editing, querying, visualization, analysis, and publishing of Pathway/Genome Database (http // bioinformatics.ai.sri.com/ptools/)... 

When a net reaction proceeds in an electrochemical cell, oxidation occurs at one electrode (the anode) and reduction takes place at the other electrode (the cathode.) We can think of the cell as consisting of two half-cells joined together by an external circuit through which electrons flow and an internal pathway that allows ions to migrate between them so as to preserve electroneutrality. 

Rapacciuolo et al. (27) demonstrated that, following agonist activation, the PrAR can undergo both caveolar-mediated as well as clathrin-mediated internalization. Indeed, these authors showed that both internalization pathways make an approximately equal contribution to PrAR internalization. These authors further showed that the nature of the protein kinase that phosphorylated the receptor determined its internalization fate. For example, PKA-mediated phosphorylation of the PrAR resulted in internalization via the caveolae pathway. In contrast, GRK phosphorylation led to the expected arrestin/clathrin internalization pathway. 

While GPCR phosphorylation at serine and threonine residues is involved in the internalization pathways of many receptors... 

Gratton SEA, Ropp PA, Pohlhaus PD, Luft JC, Madden VJ, Napier ME, DeSimone JM (2008) The effect of particle design on cellular internalization pathways. Proc Natl Acad Sci U S A 105(33) 11613-11618... 

S. Gratton, P. Ropp, P. Pohlhaus, J. Luft, V. Madden, M. Napier, and J. De Simone, The effect of particle design on cellular internalization pathways. Proceedings of the National Academy of Sciences of the United States of America, 105, 11613-11618, 2008. 

Although a large number of studies have investigated the cellular uptakes of many nanomaterials, the understanding of this field is still not sufficient. Fundamental mechanisms underlying internalization pathways and intracellular traffic at the molecular level are not well understood. More importantly, the correlation between cellular uptake and nanomaterial toxicity remains unclear. Further exploration of these issues will be necessary for the design and fabrication of nanotechnology-enhanced orthopedic materials. 

External irradiation from 3-emitters deposited on the ground usually produces a negligible contribution to the skin dose. Equation (47.16) assumes constant contamination during time T. In the case of time-dependent contamination in air or on a surface, the product Ct is replaced by the time-integration of the concentration C. Dose coefficients are listed in 0 Table 47.3 for fi-equently used radionuclides, namely for the equivalent dose to skin by P radiation (Jfp) and for the effective dose due to the contaminated air volume K, ) and the ground surface (JCyJ. Dose coefficients Kinh and King pertain to the internal pathways. 

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