Uptake routes

Chickens rapidly excrete arsenicals only 2% of dietary sodium arsenite remained after 60 h (NAS 1977), and arsanilic acid was excreted largely unchanged (Woolson 1975). Excretion of arsanilic acid by chickens was affected by uptake route excretion was more rapid if administration was by intramuscular injection than if it was oral (NRCC 1978). Studies with inorganic As+5 and chickens indicated that (Fullmer and Wasserman 1986) ... 

Based on the results described above, the chiral ferrioxamine analogs can be classified according to their uptake routes. The analogs that act both as ferrioxamine B and coprogen represent broad-range iron(III)-carriers, while others, such as the Glu derivatives, discriminating between different bacteria, correspond to narrow-range iron(III)-carriers. 

Attempting to narrow down the range of activity to a specific receptor (FoxA receptor in Yersinia enterocolitica), an additional set of chiral ferrioxamine analogs 152-155, modified at the vicinity of the terminal amine, snspected to be involved in receptor recognition was prepared . Of particular interest is the observation that 152 was utilized by the uptake system of ferrioxamine B in Yersinia enterocolitica but failed to use the ferrioxamine uptake route in Pseudomonas putida, exhibiting therefore species specificity. 

In metabolic studies with animals it is often difficult to distinguish between processes carried out by the animal and those performed by resident microorganisms, such as the gut microflora. In the following, the transformations refer to those taking place within the marine animal, whether microbially mediated or otherwise. Metabolic studies with marine animals are faced with further complications because water can be an important uptake route. A chemical, in this instance arsenic in its various forms, may undergo microbial conversions in the water, and the resultant metabolites may be accumulated by the marine animal. Thus, careful experimentation may be required to determine what is occurring inside rather than outside the animal. 

Another important uptake route for chemicals by terrestrial plants and organisms living in soils (e.g., earthworms) is uptake from soil interstitial water and/or by ingestion of soil particles. In particular, uptake of contaminants from soils by certain plant species is of great interest, because this process, which is referred to... 

Lundin P, Johansson H, Guterstam P, Holm T, Hansen M, Langel U, EL Andaloussi S (2008) Distinct uptake routes of cell-penetrating peptide conjugates. Bioconjug Chem 19 2535-2542... 

Salt marsh plants, in turn, reflect mainly sediment contaminant loads rather than the dissolved fraction, given their uptake route via the root system. Some research has been performed on the genera Spartina and Phragmites,29-33 which accumulate metals essentially in the underground... 

Perhaps the most difficult aspect of organism behavior to include in media extrapolation procedures is that relating to avoidance. Different species exhibit a diverse array of avoidance behaviors, which they may display in response to natural biotic or abiotic factors in their environment and in response to chemical exposure. Some of the most common include avoidance responses of fish to heavy metals and other contaminants (Sandheinrich 2003), aversion of contaminant-treated diets by birds (Hooper 2003), and drift in stream invertebrates (Sibley et al. 1991 Davies and Cook 1993). Such avoidance behaviors would act to reduce exposure, but are generally ignored in extrapolation approaches. Changes in behavior could potentially have importance in media extrapolation in that they could alter the relative importance of different uptake routes. For example, if a contaminant is partitioned between diet and water, and an exposed species is able to detect and avoid the contaminated food, the relative importance of water as an exposure route could be increased even though total exposure may decrease. 

Timmerman K, Andersen O. 2003. Bioavailability of pyrene to the deposit-feeding poly-chaete Arenicola marina importance of sediment versus water uptake routes. Mar Ecol Prog Ser 246 163-172. 

Source Fate Exposure Intake/uptake route... 

Peyers patches are covered by epithelial cells which can differentiate into M cells. M cells play an important role in the immunologic surveillance of the gut and are involved in specific functions like transport of particles, antigens, macromolecules. M cells seem to be involve in the absorption of intact proteins (Walker and Sanderson 1992). Peyers patches have been studied for uptake of macromolecules. Their proximal vicinity to immunocompetent cells is another hurdle for industrial use as a preferred uptake route (Daugherty and Mrsny 1999 Neutra 1998). M cells have been used to study uptake of lectins (for overview, see Daugherty and Mrsny 1999). However both cell types - Peyers patches and M cells - clearly are limited in their use as a preferred uptake route due to a small surface area they are covering and the limited capacity of absorbed molecules. 

The En. hirae CopY is a transcriptional repressor that limits expression of the CopA and CopB P-type ATPases in cells cultured in medium containing minimal Cu(II) levels (Odermatt and Solioz, 1995). An increase in medium Cu(II) levels results in Cu ion uptake, routing of the Cu(I) ions to CopY by the CopZ metallochaperone, and the subsequent dissociation of CuCopY from the copA and copB genes (Strausak and Solioz, 1997). 

The first direct indication for the existence of a Ca release route separated from the uptake pathway came from the observation by Rossi et al. [80] that ruthenium red, which completely blocks the electrophoretic uptake of Ca, fails to inhibit the release of accumulated Ca induced by uncouplers. Evidently, since the uptake route was blocked in this experiment by ruthenium red (and later experiments have shown that ruthenium red remains bound in the presence of uncouplers [81]), the exit of Ca had to occur in this case through an independent pathway. Uncouplers, however, are unphysiological means of inducing Ca release, and have no relevance to the release mechanism operating in vivo, which is known to proceed at a much slower rate [82]. 

In catfish aquaculture, offensive odors can be rapidly absorbed in the flesh of the fish. The major uptake route for geosmin and MIB is across the gills [18], and these compounds are primarily stored in the adipose tissue [29]. Elimination of these odorous compounds is much slower than the uptake rate, and elimination rate decreases as water temperature decreases and adipose tissue content of the catfish increases [30]. 

The most important uptake route for uranium is ingestion of food and drinking water, as shown in Table 26.1-2 (see Chapter 26.1, Section 26.1.7). The daily dietary intake of U for Ukrainian males is estimated at 7.8 mBq (Shiraishik et al. 1997), with typical daily intake values being 0.16 Bq for 0.0005 Bq for U, and 0.16 Bq for U. Military use of depleted uranium led to inhalation during combat and to shrapnel contamination (Bleise... 

Relevant uptake routes of solvents are absorption from the lung and pereutaneous absorption. The intestinal uptake is usually eaused by aeeidents or by intent. The absorption rate is influeneed by various faetors. 

The major route of uptake for PAHs has been debated for years. For the more water-soluble PAHs, it is believed that the main route of uptake is through ventilated water and that the more hydrophobic compounds are taken in mainly through ingestion of food or sediment. There are many variables, such as chemical hydrophobicity, uptake efficiency, feeding rate, and ventilatory volume, which may affect the outcome. The route of uptake may be an important issue for short-term events however, under long-term exposure and equilibrium conditions between water, prey, and sediment, the route of uptake may be immaterial because the same tissue burdens will be achieved regardless of uptake routes. The key assumption of equilibrium between these different compartments may, however, rarely occur for PAHs. 

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