scholarly journals Benzothiazole Degradation by Rhodococcus pyridinovorans Strain PA: Evidence of a Catechol 1,2-Dioxygenase Activity

2002 ◽  
Vol 68 (12) ◽  
pp. 6114-6120 ◽  
Author(s):  
Nicolas Haroune ◽  
Bruno Combourieu ◽  
Pascale Besse ◽  
Martine Sancelme ◽  
Thorsten Reemtsma ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Reversed Phase ◽  
Culture Conditions ◽  
Ionization Mass ◽  
Structure Detection ◽  
Catechol 1,2 Dioxygenase ◽  
Kinetics Of ◽  
C Nmr

ABSTRACT The pathway for biodegradation of benzothiazole (BT) and 2-hydroxybenzothiazole (OBT) by Rhodococcus pyridinovorans strain PA was studied in detail. The kinetics of biodegradation were monitored by in situ 1H nuclear magnetic resonance (NMR) in parallel with reversed-phase high-performance liquid chromatography (HPLC). Successive oxidations from BT to OBT and then from OBT to dihydroxybenzothiazole were observed. Further insight was obtained by using a mutant strain with impaired ability to grow on BT and OBT. The precise structure of another intermediate was determined by in situ two-dimensional 1H-13C NMR and HPLC-electrospray ionization mass spectrometry; this intermediate was found to be a ring-opening product (a diacid structure). Detection of this metabolite, together with the results obtained by 1H and 19F NMR when cells were incubated with 3-fluorocatechol, demonstrated that a catechol 1,2-dioxygenase is involved in a pathway for biodegradation of BTs in this Rhodococcus strain. Our results show that catechol 1,2-dioxygenase and catechol 2,3-dioxygenase activities may both be involved in the biodegradation of BTs depending on the culture conditions.

Induction and Transcription Studies of the Dextransucrase Gene in Leuconostoc mesenteroides NRRL B-512F

1999 ◽  
Vol 65 (12) ◽  
pp. 5504-5509 ◽  
Author(s):  
M. Quirasco ◽  
A. López-Munguía ◽  
M. Remaud-Simeon ◽  
P. Monsan ◽  
A. Farrés
Keyword(s):  
High Performance ◽  
Leuconostoc Mesenteroides ◽  
Carbon Sources ◽  
Promoter Sequence ◽  
Culture Conditions ◽  
Start Codon ◽  
Reaction Products ◽  
Product Specificity ◽  
First Time

ABSTRACT Dextransucrase production by Leuconostoc mesenteroidesNRRL B-512F in media containing carbon sources other than sucrose is reported for the first time. Dextransucrases were analyzed by gel electrophoresis and by an in situ activity assay. Their polymers and acceptor reaction products were also compared by 13C nuclear magnetic resonance and high-performance liquid chromatography techniques, respectively. From these analyses, it was found that, independently of the carbon source, L. mesenteroides NRRL B-512F produced dextransucrases of the same size and product specificity. The 5′ ends of dextransucrase mRNAs isolated from cells grown under different culture conditions were identical. Based on this evidence, we conclude that dextransucrases obtained from cells grown on the various carbon sources result from the transcription of the same gene. The control of expression occurs at this level. The low dextransucrase yields from cultures in d-glucose ord-fructose and the enhancement of dextransucrase gene transcription in the presence of sucrose suggest that an activating phenomenon may be involved in the expression mechanism. Dextransucrase mRNA has a size of approximately 4.8 kb, indicating that the gene is located in a monocistronic operon. The transcription start point was localized 34 bp upstream from the ATG start codon. The −10 and −35 sequences found, TATAAT and TTTACA, were highly homologous to the only glycosyltransferase promoter sequence reported for lactic acid bacteria.

scholarly journals Is Our Natural Food Our Homeostasis? Array of a Thousand Effect-Directed Profiles of 68 Herbs and Spices

2021 ◽  
Vol 12 ◽  
Author(s):  
Tamara Schreiner ◽  
Dorena Sauter ◽  
Maren Friz ◽  
Julia Heil ◽  
Gertrud Elisabeth Morlock
Keyword(s):  
Bioactive Compounds ◽  
High Performance ◽  
Reversed Phase ◽  
Natural Food ◽  
Ionization Mass ◽  
Photodiode Array Detection ◽  
Bioactive Substances ◽  
Traditional Medicines ◽  
Beneficial Effects ◽  
Herbs And Spices

The beneficial effects of plant-rich diets and traditional medicines are increasingly recognized in the treatment of civilization diseases due to the abundance and diversity of bioactive substances therein. However, the important active portion of natural food or plant-based medicine is presently not under control. Hence, a paradigm shift from quality control based on marker compounds to effect-directed profiling is postulated. We investigated 68 powdered plant extracts (botanicals) which are added to food products in food industry. Among them are many plants that are used as traditional medicines, herbs and spices. A generic strategy was developed to evaluate the bioactivity profile of each botanical as completely as possible and to straightforwardly assign the most potent bioactive compounds. It is an 8-dimensional hyphenation of normal-phase high-performance thin-layer chromatography with multi-imaging by ultraviolet, visible and fluorescence light detection as well as effect-directed assay and heart-cut of the bioactive zone to orthogonal reversed-phase high-performance liquid chromato-graphy−photodiode array detection−heated electrospray ionization mass spectrometry. In the non-target, effect-directed screening via 16 different on-surface assays, we tentatively assigned more than 60 important bioactive compounds in the studied botanicals. These were antibacterials, estrogens, antiestrogens, androgens, and antiandrogens, as well as acetylcholinesterase, butyrylcholinesterase, α-amylase, α-glucosidase, β-glucosidase, β-glucuronidase, and tyrosinase inhibitors, which were on-surface heart-cut eluted from the bioautogram or enzyme inhibition autogram to the next dimension for further targeted characterization. This biological-physicochemical hyphenation is able to detect and control active mechanisms of traditional medicines or botanicals as well as the essentials of plant-based food. The array of 1,292 profiles (68 samples × 19 detections) showed the versatile bioactivity potential of natural food. It reveals how efficiently and powerful our natural food contributes to our homeostasis.

scholarly journals Model Discrimination for Hydrogen Peroxide Consumption towards γ-Alumina in Homogeneous Liquid and Heterogeneous Liquid-Liquid Systems

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1476
Author(s):  
Daniele Di Menno Di Bucchianico ◽  
Wander Y. Perez-Sena ◽  
Valeria Casson Moreno ◽  
Tapio Salmi ◽  
Sébastien Leveneur
Keyword(s):  
Hydrogen Peroxide ◽  
Ring Opening ◽  
Oxidation Mechanism ◽  
Liquid System ◽  
Side Reactions ◽  
Hydroxyl Groups ◽  
Homogeneous Liquid ◽  
Liquid Systems ◽  
Kinetics Of

The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

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