scholarly journals Biodegradation of the Polyketide Toxin Cercosporin

2002 ◽  
Vol 68 (9) ◽  
pp. 4173-4181 ◽  
Author(s):  
Thomas K. Mitchell ◽  
William Scott Chilton ◽  
Margaret E. Daub
Keyword(s):  
Xanthomonas Campestris ◽  
Culture Medium ◽  
Plant Pathogens ◽  
Spectroscopic Analysis ◽  
Bacterial Degradation ◽  
Pathogenicity Determinant ◽  
Kinetics Of Degradation ◽  
Oxygen Insertion ◽  
Kinetics Of ◽  
Cytochrome P 450

ABSTRACT Cercosporin is a non-host-specific polyketide toxin produced by many species of plant pathogens belonging to the genus Cercospora. This red-pigmented, light-activated toxin is an important pathogenicity determinant for Cercospora species. In this study, we screened 244 bacterial isolates representing 12 different genera for the ability to degrade cercosporin. Cercosporin degradation was determined by screening for the presence of cleared zones surrounding colonies on cercosporin-containing culture medium and was confirmed by assaying the kinetics of degradation in liquid medium. Bacteria belonging to four different genera exhibited the cercosporin-degrading phenotype. The isolates with the greatest cercosporin-degrading activity belonged to Xanthomonas campestris pv. zinniae and X. campestris pv. pruni. Isolates of these pathovars removed over 90% of the cercosporin from culture medium within 48 h. Bacterial degradation of red cercosporin was accompanied by a shift in the color of the growth medium to brown and then green. The disappearance of cercosporin was accompanied by the appearance of a transient green product, designated xanosporic acid. Xanosporic acid and its more stable lactone derivative, xanosporolactone, are nontoxic to cercosporin-sensitive fungi and to plant tissue and are labile in the presence of light. Detailed spectroscopic analysis (to be reported in a separate publication) of xanosporolactone revealed that cercosporin loses one methoxyl group and gains one oxygen atom in the bacterial conversion. The resulting chromophore (4,9-dihydroxy-3-oxaperlylen-10H-10-one) has never been reported before but is biosynthetically plausible via oxygen insertion by a cytochrome P-450 enzyme.

Impact of the composition of the bacterial population and additional carbon source on the pathway and kinetics of degradation of endosulfan isomers

2017 ◽  
Vol 19 (7) ◽  
pp. 964-974 ◽  
Author(s):  
Swatantra Pratap Singh ◽  
Saumyen Guha ◽  
Purnendu Bose
Keyword(s):  
Carbon Source ◽  
Organochlorine Pesticide ◽  
Bacterial Population ◽  
Bacterial Degradation ◽  
Kinetics Of Degradation ◽  
Kinetics Of ◽  
Additional Carbon Source

Abiotic and bacterial degradation is presented for the two isomers α- and β- of the organochlorine pesticide endosulfan, denoted as ES-1 and ES-2, respectively.

Effect of C6-Volatiles on Bioluminescent Plant Pathogens

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557d-557
Author(s):  
Jennifer Warr ◽  
Fenny Dane ◽  
Bob Ebel
Keyword(s):  
Biological Activity ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Genetically Engineered ◽  
The Other ◽  
Computer Assisted ◽  
Signal Molecules ◽  
Low Concentrations

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.

scholarly journals Genomic insights advance the fight against black rot of crucifers

2021 ◽  
Vol 87 (3) ◽  
pp. 127-136
Author(s):  
Zoë E. Dubrow ◽  
Adam J. Bogdanove
Keyword(s):  
Virulence Factors ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Impact Resistance ◽  
Resistance Breeding ◽  
Genetic Data ◽  
Black Rot ◽  
Inoculum Sources ◽  
New Knowledge ◽  
The World

AbstractXanthomonas campestris pv. campestris, the causal agent of black rot of crucifers, was one of the first bacterial plant pathogens ever identified. Over 130 years later, black rot remains a threat to cabbage, cauliflower, and other Brassica crops around the world. Recent genomic and genetic data are informing our understanding of X. campestris taxonomy, dissemination, inoculum sources, and virulence factors. This new knowledge promises to positively impact resistance breeding of Brassica varieties and management of inoculum sources.

scholarly journals Comparative Study of Chemical Stability of Two H1Antihistaminic Drugs, Terfenadine and ItsIn VivoMetabolite Fexofenadine, Using LC-UV Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Anna Gumieniczek ◽  
Anna Berecka-Rycerz ◽  
Rafał Pietraś ◽  
Izabela Kozak ◽  
Karolina Lejwoda ◽  
...  
Keyword(s):  
Comparative Study ◽  
Chemical Stability ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of Degradation ◽  
Effects Of Temperature ◽  
High Doses ◽  
Antihistaminic Drugs ◽  
Kinetics Of

A comparative study of chemical stability of terfenadine (TER) and itsin vivometabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

The Kinetics of Degradation of Chloramphenicol in Solution

1954 ◽  
Vol 43 (3) ◽  
pp. 129-134 ◽  
Author(s):  
Takeru Higuchi ◽  
Charles D. Bias ◽  
Arnold D. Marcus
Keyword(s):  
Kinetics Of Degradation ◽  
Kinetics Of

scholarly journals New Culture Medium to Xanthan Production by Xanthomonas campestris pv. campestris

2011 ◽  
Vol 51 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Cíntia Regina Rodrigues Carignatto ◽  
Kassandra Sussi Mustafé Oliveira ◽  
Valéria Marta Gomes de Lima ◽  
Pedro de Oliva Neto
Keyword(s):  
Xanthomonas Campestris ◽  
Culture Medium ◽  
Xanthan Production ◽  
Xanthomonas Campestris Pv Campestris
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