Bioactive zone

Binodal curves, 20 320-321 Bins concept, 70 32 Bioaccumulation, of herbicides, 73 310 Bioactive barrier, defined, 3 758t Bioactive fixation, 72 611 Bioactive food ingredients, 7 7 646 Bioactive nutritions, 7 7 645t Bioactive substances identifying, 77 646 safety of, 77 647 Bioactive zone, defined, 3 758t Bioadhesive agents, 9 48, 49 Bioadhesive drug delivery systems, 9 45... 

TLC or HPTLC combined with bioluminescence detection is an important method for the EDA of bioactive zones on the layer. Bioluminescent bacteria can be used or other types of bioassays can be carried out. A system incorporating V. fischeri, HPTLC, and detection with a CCD camera... 

Bioluminescence can be used for spedfic detection of separated bioactive compounds on layers (BioTLC) [46]. After development and drying the mobile phase by evaporation, the layer is coated with microorganisms by immersion of the plate. Single bioactive substances in multicomponent samples are located as zones of differing luminescence. The choice of the luminescent cells determines the specificity of detection. A specific example is the use of the marine bacterium Vibrio fischeri with the BioTLC format. The bioluminescence of the bacteria cells on the layer is reduced by toxic substances, which are detected as dark zones on a fluorescent background. BioTLC kits are available from ChromaDex, Inc. (Santa Ana, CA). 

Targeted screening approaches specifically zone in upon plants more likely to contain bioactive molecules in the first place. For example, plants which seem to be immune from predation may well be producing substances toxic to, for example, insects. These in turn are also likely to have some effect on human cells. 

Hepatic necrosis can be classified by the zone of the liver tissue affected. Xenobiotics, such as acetaminophen or chloroform, that undergo bioactivation to toxic intermediates cause necrosis of the cells surrounding the central veins (centrilobular) because the components of the cytochrome P450 system are found in those cells in abundance. At higher doses or in the presence of agents that increase the synthesis of cytochrome P450 (inducers), the area of necrosis may incorporate the... 

Secondary metabolites from deep-sea organisms are a recent notion. Representative examples are shown in the charts of Chapter 7 and, on a broader basis, in Table 9.III. In the latter, the depth range, species, metabolites, and their bioactivity or technological use are indicated for the same zones as in Chapter 7. This affords an integrated perspective of the ecological and taxonomic distribution of the productive organisms and their secondary metabolites at the various depths. 

Yue, M.-E. and Shi, Y.-R, Application of l-alkyl-3-methylimidazolium-based ionic liquids in separation of bioactive flavonoids by capillary zone electrophoresis, /. Sep. Set., 29, 272-276,2006. 

Since terrestrial actinomycetes have been such prolific producers of bioactive molecules, it was natural to investigate marine species of the same group. Therefore, it was no surprise that actinomycetes isolated from the marine sediments have proven to be one of the most prolific sources of bioactive secondary compounds.6-7 Their distribution in sediments varies depending on the depth from which the sample was collected. In several studies, Streptomyces predominated in near-shore marine sediments, but decreased dramatically past the sublittoral zone. In contrast, actinoplanetes are found in greater numbers as the distance from the shoreline increases. 

Pyrolysis reactions in fuel-rich flame zones may lead, however, to emissions of polycyclic aromatic compounds (PACs) and soot. The close correlation between the concentrations of PACs and the bioactivity of flame samples is indicative of some of the health hazards involved in the emissions of PACs (Fig. 3). Fluxes of PAC species determined in fuel-rich, natural gas turbulent diffusion flames show the build up of hydrocarbons of increasing molecular weight along flames (Fig. 4). It is postulated that PACs are formed by the successive addition of C2 through C5 hydrocarbons to aromatic compounds (Fig. 5). 

Uni-isouni pathway Typified by ligand-induced solute unfolding-folding phenomena at the stationary phase surface single elution zone observed but time-dependent loss of mass and bioactivity possible when the rate constants for interconversion, 21 > ki2. 

Isobi-uni pathway Typified by solvent-induced, time-dependent biphasic unfoldingrefolding of solute in the mobile phase but stabilization of the tertiary structure by the ligate surface if k l2 > k H characterized by high mass recovery, elution of a single zone with apparent half-life for loss of bioactivity larger than in the mobile phase alone. 

Isobi-uni pathway Typified by mobile-phase-induced and ligate-induced biphasic unfolding-refolding of the solute characterized by the time-dependent loss of mass and bioactivity with the emergence of a second, often later eluting inactive zone of inactive solute if ktl, k4 k2l, ki4. 

P h y t o c h e m i c a l investigations of plant species of Parthenium, Encelia and Pi coria (Asteraceae) from semi-arid and arid zones of the United States and Mexico has resulted in the isolation and identification of numerous sesquiterpene lactones and benzopyrans that are active insect feeding deterrents. The chemistry, biological effects and possible mode of action of bioactive pseudoguaianolides and chromenes are reviewed. 

An important conclusion of the Toggweiler and Carson (1995) study is that the EUC is the most important source of N to the equatorial zone paradoxically, NO3 concentration in the EUC is lower than in the surrounding waters. The resolution of this apparent paradox lies in the nonconservative nature of bioactive elements such as N. The primary mass balance for N is between zonal advection by the EUC and sedimentation of particulate N, while the mass balance for water is between zonal advection and poleward advection of surface waters that have been depleted of N by the biota. This is not intended to minimize the importance of vertical advection, which is of course very important for equatorial ecosystems, but to understand sources to the region as a whole, by calculating fluxes in and out of a box encompassing the upper equatorial ocean down to the base of the thermocHne. 

EtOAc extract of a marine Bacillus sp. Sc026 culture broth, in bioactivity-guided fractionation, led to the isolation of two new compounds, 7-O-succinyl macrolactin F 229 and 7-(9-succinyl macrolactin A 230. Both exhibited antibacterial activity against Bacillus subtilis and Staphylococcus aureus, (inhibition zones of 8-28 mm at 50-100 pg/disk). 

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