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Highly Toxic (highly + toxic)
Selected AbstractsHow to determine free Gd and free ligand in solution of Gd chelates.CONTRAST MEDIA & MOLECULAR IMAGING, Issue 5 2006A technical note Abstract Gd(III) chelates are often used as reporting probes in magnetic resonance imaging applications. Their use relies on the assumption that their high stability ensures against the release of free ligand and free Gd3+ ions, which are both highly toxic to living systems. The presence of free Gd3+ ions may have a profound effect on the contrast in the MR image as they may form highly hydrated, macromolecular complexes endowed with very high relaxivity thus providing erroneous information on the extent of the contrast effect induced by the given reporting probe. Although the stability of a given complex may be high enough, the complexation step could not have been completed. Therefore any Gd complex preparation has to be carefully checked for the content of free ligand and free metal ions. Herein the currently used procedures that allow an assessment of the amounts of free metal ions and free ligand in a solution of a given Gd complex are described in detail. Copyright © 2006 John Wiley & Sons Ltd. [source] Recombinant Bacillus thuringiensis strain shows high insecticidal activity against Plutella xylostella and Leptinotarsa decemlineata without affecting nontarget species in the fieldJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2008G. Wang Abstract Aims:, To construct a recombinant Bacillus thuringiensis (Bt) strain with broad insecticidal spectrum and investigate its impact on nontarget organisms in field. Method and Results:, The cry -type gene of wild Bt strain UV17 was identified and a novel cry1Ba gene was cloned. The cry3Aa7 gene, which was highly toxic to coleopteran pests, was introduced into UV17, and a recombinant strain designated as UV173A was obtained. Bioassay results showed that UV173A was not only highly toxic against Plutella xylostella (50% lethal concentration [LC50] = 18·03 ,g ml,1), but also against coleopteran Leptinotarsa decernlineata (LC50 = 0·19 mg ml,1). The recombinant strain was then tested in field trials to monitor its spatial variation of population and to investigate the impact on nontarget invertebrates. Conclusions:, A recombinant Bt stain UV173A with broad insecticidal spectrum was obtained, and it did not cause adverse effects on the population of nontarget organisms. Significance and Impact of the Study:, The results obtained here indicated that cry1Ba3 gene may be useful for the resistance management of P. xylostella, and the recombinant stain UV173A was potential for field application against some crucifer vegetable pests as well as L. decemlineata. [source] Small peptides, big world: biotechnological potential in neglected bioactive peptides from arthropod venoms,JOURNAL OF PEPTIDE SCIENCE, Issue 11 2005Adriano M. C. Pimenta Abstract Until recently, a toxinologist's tasks involved the search for highly toxic or lethal toxins in animal venoms that could explain the harmful effects in clinically observed symptoms. Most of these toxins were put on evidence using a function to structure approach, in which a biological phenomena observation usually guided the isolation and characterization of the causative molecule. Paving this way, many toxins were promptly purified because of their readily observed effect. Nevertheless, small molecules with micro-effects that are not easily visualized can be relatively neglected or poorly studied. This situation has changed now with the advent of the sensitivity, resolution and accuracy of techniques such as mass spectrometry and proteomic approaches used in toxinology. Taking advantage of these methodologies, small peptides with ,newly exploited' biological activities such as vasoactive, hormone-like, antimicrobial and others have been recently given much more attention, enlarging the known repertoire of bioactive molecules found in animal venoms. This article aims to review current knowledge on small biologically active peptides (<3 kDa) found in arthropod venoms and discuss their potentialities as new drug candidates or therapeutic lead compounds. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source] Detoxification of the explosive 2,4,6-trinitrotoluene in Arabidopsis: discovery of bifunctional O - and C -glucosyltransferasesTHE PLANT JOURNAL, Issue 6 2008Fernando Gandia-Herrero Summary Plants, as predominantly sessile organisms, have evolved complex detoxification pathways to deal with a diverse range of toxic chemicals. The elasticity of this stress response system additionally enables them to tackle relatively recently produced, novel, synthetic pollutants. One such compound is the explosive 2,4,6-trinitrotoluene (TNT). Large areas of soil and groundwater are contaminated with TNT, which is both highly toxic and recalcitrant to degradation, and persists in the environment for decades. Although TNT is phytotoxic, plants are able to tolerate low levels of the compound. To identify the genes involved in this detoxification process, we used microarray analysis and then subsequently characterized seven uridine diphosphate (UDP) glycosyltransferases (UGTs) from Arabidopsis thaliana (Arabidopsis). Six of the recombinantly expressed UGTs conjugated the TNT-transformation products 2- and 4-hydroxylaminodinitrotoulene, exhibiting individual bias for either the 2- or the 4-isomer. For both 2- and 4-hydroxylaminodinitrotoulene substrates, two monoglucose conjugate products, confirmed by HPLC-MS-MS, were observed. Further analysis indicated that these were conjugated by either an O - or C -glucosidic bond. The other major compounds in TNT metabolism, aminodinitrotoluenes, were also conjugated by the UGTs, but to a lesser extent. These conjugates were also identified in extracts and media from Arabidopsis plants grown in liquid culture containing TNT. Overexpression of two of these UGTs, 743B4 and 73C1, in Arabidopsis resulted in increases in conjugate production, and enhanced root growth in 74B4 overexpression seedlings. Our results show that UGTs play an integral role in the biochemical mechanism of TNT detoxification by plants. [source] Rational Design of Solid Catalysts for the Selective Use of Glycerol as a Natural Organic Building BlockCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 7 2008François Jérôme Dr. Abstract Glycerol is the main co-product of the vegetable oils industry (especially biodiesel). With the rapid development of oleochemistry, the production of glycerol is rapidly increasing and chemists are trying to find new applications of glycerol to encourage a better industrial development of vegetable oils. In this Review, attention is focused on the selective use of glycerol as a safe organic building block for organic chemistry. An overview is given of the different heterogeneous catalytic routes developed by chemists for the successful and environmentally friendly use of glycerol in sustainable organic chemistry. In particular, the effects of different catalyst structural parameters are discussed to clearly highlight how catalysis can help organic chemists to overcome the drawbacks stemming from the use of glycerol as a safe organic building block. It is shown that heterogeneous catalysis offers efficient routes for bypassing the traditional use of highly toxic and expensive epichlorohydrin, 3-chloro-1,2-propanediol, or glycidol, which are usually used as a glyceryl donor in organic chemistry. [source] | |||||||||||||