Ayoub BENSAKHRIA · @ayoubbensakhria. Toxicologist. analyticaltoxicology. com. Joined September Metal and metalloid biotransformations in South African acid mine drainage systems” .. la présence de composés très toxiques comme le plomb, l’arsenic ou le. d’effets toxiques précoces et tardifs pour des molécules En effet, les poissons étant capables de biotransformation, ils peuvent donc.
|Published (Last):||5 January 2018|
|PDF File Size:||17.47 Mb|
|ePub File Size:||1.42 Mb|
|Price:||Free* [*Free Regsitration Required]|
Biotransformation — Wikipédia
The gene for albicidin detoxifica- of phytotoxins associated with Streptomyces scabies, the causal tion from Pantoea dispersa encodes an esterase and attenuates organism of potato common scab.
The txtAB genes of the plant pathogen Streptomyces destruxins: Revision received 20 November The experiment was carried out four times with similar trends in the results. Samples were taken at various intervals effect. These fungi were con- dia were then extracted with equivalent volumes of ethyl ac- sidered most likely to have lignin-degrading abilities and the etate.
Controls received absolute ethanol only. This provided a concentration of for 7 and 10 days, respectively. Biodegradation and transfor- Goyer, C. The me- isolates collected from rotting wood. Log In Sign Up.
Toxic biotransformations – definition of toxic biotransformations by The Free Dictionary
In initial endeavours to ascer- millilitre volumes of the nutrient media were pipetted into tain if biological detoxification of thaxtomin A was possible, sterile mL Erlenmeyer flasks for testing thaxtomin A various bacteria of unknown classification were screened for transformations.
When applied at concentrations as amount of thaxtomin A present at day 3. Numbers refer to carbons correlated to the hydrogen at the position listed in the first column. Potato grisea genes for pathogenicity and virulence identified through Assoc.
In Manual of environmen- Streptomyces scabies mutants altered boitransformation thaxtomin A produc- tal microbiology. Inoculum levels also influ- 7. Patent Office 30 pages. By day 3, however, such cultures had significant the fungus completely eliminate thaxtomin A from the cul- amounts of M In these preliminary studies performed using mini- from 1 to 14 days after inoculation.
The products, mass spectral data for the major metabolite M-5 dry weights of the ethyl acetate extracts from such cultures indicated it to be a probable dehydration or cyclodehydration ranged from about 4 to 14 mg by day 5. The fungal isolate was identified by on silica gel TLC analysis of the ethyl acetate extracts. Mass spectral data for the only other metabolite of significant yield, i. The tent in their activity. More gene manipulations in The ef- matographic and molecular weight data for the metabolites.
HPLC, high-performance liquid chromatography.
Table 1 summarizes chro- ously King and Lawrence ; Goyer et al. Remember me on this computer. American Society for tion. Values in parentheses are the standard error. Quantitative relationships among thaxtomin A production, potato scab severity, and fatty acid composition in Streptomyces. Generally, olites resulting from the biotransformation of thaxtomin A after 1 week of incubation on a shaker, the thaxtomin A con- by a fungus isolated from the bark of a decomposing decidu- centration was either much reduced or it was not detectable ous tree likely beech.
The maximum Metabolite identification fungal dry weight of 18—21 mg was obtained by day 3 in In characterization of the thaxtomin A biotransformatio both the presence and absence of thaxtomin A Hiotransformation 2. Only in a few instances toxiqes lation. A number of studies Press Web site at http: Magnaporthe bies isolates from scab infected potato tubers. When assayed on aseptically produced mini-tubers, the major metabolites proved to be much less phytotoxic than thaxtomin A.
Structural formulas of metabolites M-2 and M Of several hundred microorganisms randomly selected from the environment, only a fungal isolate identified as Aspergillus niger van Tiegham var. Toxiquds comparison of biotrsnsformation respective 1H Acknowledgements NMR spectra Table 5 demonstrated essential differences only toxiuqes the C substituents, i. Occasionally, however, even some of the higher dos- al. Aspergillus niger van Tiegham var.
The present study was initi- ated to explore control technologies based on the involvement of phytotoxins as essential factors in the dis- Received 14 August In the process of repurifying the M-3 sample after 1H to the eventual dehydration products M-3 and M A quan- Novel in vivo use of polyvalent Streptomyces phage to disinfest titative method for determining soil populations of Streptomyces Streptomyces scabies-infected seed potatoes.
The relative proportions of these metabolites did not enced the rate of thaxtomin A transformation. In some experiments, Nishino and Spain Summary of molecular weight MW and chromatographic data for thaxtomin A transformation biotranxformation M-1 to M Similarly, extracts from full- and half-strength 1.
This may also have contributed to PDB under both shaking and still conditions also contained the low levels of fungal growth in this media and to perhaps compounds that migrated with thaxtomin A and metabolites. With the low- change significantly after 4 days of incubation Table 2. Synthetic studies related to the structural determinations confirmed that the presence of a C-4 nitro and a C phenyl moiety are requi- sites for phytotoxicity in these compounds King et al. The phytotoxins associated with common scab niotransformation potato disease consist of 4-nitroindol-3yl containing dioxo- piperazines, and thaxtomin A Fig.