Translocation configuration

TABLE 2. Translocation Configurations Recorded after Irradiation of Spermato-... 

TABLE 3. Minimum and Maximum Incidence per Animal of Spermatocytes with Translocation Configurations after Spermatogonial Irradiation... 

Reference X-ray dose (r) Spermatocytes with translocation configurations Minimum (%) Maximum (%) ... 

TABLE 6, Types of Translocation Configuration in Spermatocytes of Presumptively Fertile and Sterile Males after Paternal Postmeiotic Radiation ... 

Inhibitors must possess chemical and physical properties that will ensure absorption by root tips or penetration by foliar surfaces, and translocation to the active site. Once there they must assume the precise spatial configuration required to complement the molecular architecture of the active center if they are to block the key reaction. A comprehension of comparative biochemistry and information on how plants differ in the architecture of the reactive sites should assist in developing truly selective herbicides. 

The specific behaviour of unsaturated fatty acids under oxidation is determined by the position and the number of double bonds in the fatty acid molecule. The stepwise oxidation of an unsaturated acid to the position of a double bond in it proceeds in a manner similar to that of saturated acid oxidation. If the double bond retains the same configuration (trans-configuration) and position (A2,3) as those of the enoyl-CoA, which is produced during the oxidation of saturated fatty acids, the subsequent oxidation proceeds via conventional route. Otherwise, the oxidation reaction proceeds with the involvement of an accessory enzyme, A3,4-CiS-A2,3jrans-enoyl-CoA isomerase this facilitates the translocation of the double bond to an appropriate position and alters the double-bond configuration from cis to trans. 

Reciprocal Translocations. These can result from the exchange of chromosomal segments between two chromosomes and, depending on the position of the centromeres in the rearranged chromosomes, different configurations will result. 

The 13-c/j retinal-chromophore in dark-adapted bacteriorhodopsin exhibits a very different photocycle, whose predominant intermediate has an absorption maximum at 610 nm [199], and which contains no intermediate [202,238] analogous to M. The 610 nm intermediate will decay to either the 13-c/s chromophore or the dW-trans form, the latter pathway being responsible for the phenomenon of light-adaptation [199]. This pathway does not explain, however, why monomeric bacteriorhodopsin shows poor light-adaptation [168,239]. The chromophore in the 13-c/s configuration is not associated with proton translocation [240]. Indeed, reconstitution of bacterio-opsin with 13-demethyl retinal, which traps the retinal moiety in the 13-c/s configuration, results [241] in a non-transporting photocycle. 

For each BoNT serotype, the dichain form constimtes the active configuration of the neurotoxin the isolated LC and HC are devoid of systemic toxicity. The absence of toxicity is consistent with findings that the LC cannot gain access to the cytosol unless it is coupled to the HC and that the HC lacks the ability to inhibit neurotransmitter release (Stecher et al., 1989 Goodnough et al., 2002). The isolated LC does, however, remain enzymatically active as evidenced by its ability to inhibit exocytosis from permeabilized chromaffin cells (Stecher et al., 1989), by its ability to cleave SNARE proteins in cell-free assays (Adler et al., 1998), and by its capacity to inhibit ACh release in skeletal muscle when delivered by liposomes (de Paiva and Dolly, 1990). It is not clear whether any portion of the HC is translocated along with the LC, and if so, whether it exerts a role in enhancing the catalytic activity or stability of the LC. 

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