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.

Author: Tusho Shakarr
Country: Belarus
Language: English (Spanish)
Genre: Literature
Published (Last): 18 July 2012
Pages: 117
PDF File Size: 2.92 Mb
ePub File Size: 11.13 Mb
ISBN: 910-5-63538-209-8
Downloads: 69838
Price: Free* [*Free Regsitration Required]
Uploader: Toramar

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.

HPLC, high-performance liquid chromatography. George Lazarovits Larry A.

In- Methods of containment are generally inadequate or biotransfofmation fection occurs mainly through the lenticels of immature tu- sistent McKenna et al. Five- bioactivity King et al. In contrast, thaxtomin A Tiegham var.

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. Click here to sign up. The transformation of 0.

Mean of three replications of two separate experiments. In this report we describe the pu- the replications of each treatment were bulked before analy- rification, characterization, and relative bioactivity of metab- sis and in others they were analyzed individually.

Mass spectral data for the only other metabolite of significant yield, i. This eliminated symptoms and hence crop damage Zhang et al. Structural formulas of metabolites M-2 and M In Manual of environmen- Streptomyces scabies mutants altered in thaxtomin A produc- tal microbiology.


Synthetic studies related to the structural determinations confirmed that the presence biofransformation 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 of potato disease consist of 4-nitroindol-3yl containing dioxo- piperazines, and thaxtomin A Fig.


Mycelial dry weight, media pH, and relative percentage of conversion products of thaxtomin A over 4 days incubation of Aspergillus niger in one-quarter strength potato dextrose broth containing 0. More gene manipulations biotransformationn Help Center Find new research papers in: The tent in their activity. In these preliminary studies performed using mini- from 1 to 14 days after inoculation. 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.

The gene for albicidin bjotransformation of phytotoxins associated with Streptomyces scabies, the causal tion from Pantoea dispersa encodes an esterase and attenuates organism of potato common scab. Generally, olites resulting from the biotransformation of thaxtomin A after 1 week of incubation on a shaker, biottansformation 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.

Inoculum levels also influ- 7.


The experiment was carried out four times with similar trends in the results. Of the four remaining me- tial for biocontrol stratagems based on phytotoxin tabolites, only two, i.

In initial endeavours to ascer- millilitre volumes of the nutrient dew 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. Plant pathogenicity in the genus Streptomyces. 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 biotransfprmation 14 mg by day 5.

Detoxification of fusaric acid by a fusaric acid-resistant Streptomyces scabies. King, and Larry A.

biotransformation — с французского

In some experiments, Nishino and Spain With the hoxiques change significantly after 4 days of incubation Table 2.


Both methods utilized retained the 4-nitroindole moiety. Table 1 summarizes chro- ously King and Lawrence ; Goyer et al. When the gene Fig. Controls received absolute ethanol only. Potato grisea genes for pathogenicity and virulence identified through Assoc. A subsequent compar- reflection of its substantially revamped structure in compari- ative 1H NMR analysis Table 4 of M-2 indicated it to biotransformatioj a son with thaxtomin A and is a prime example of the poten- C conformer Fig.

Biotransformation — Wikipédia

Log In Sign Up. The pH of the me- analog of thaxtomin A see Table 1. Enter the email address you signed up with and we’ll biotramsformation you a reset link. This provided a concentration of for 7 and 10 days, respectively. Values in parentheses are the standard error.

The txtAB genes of the plant pathogen Streptomyces destruxins: Structural formula of metabolite M When applied at biotransdormation as amount of thaxtomin A present at day 3.

The me- isolates collected from rotting wood.

Samples were taken at various intervals effect. The rate and extent of transformation of thaxtomin A was tested under a variety of conditions, including dif- ferent growth media, biomass concentrations, biktransformation periods, and shaker speeds. The ex- NMR studies, it was discovered that some conversion to the ceptional loss of bioactivity observed for M-5 is assumed a M-2 Fig.

Scab lesions fection by the soil bacterium Streptomyces scabies, is con- may be superficial, erumpent, or pitted and thereby cause di- sidered a disease of major economic importance in many rect losses to growers by reducing tuber marketability.

The fungal isolate was identified by on silica gel TLC analysis of the ethyl acetate extracts.