scholarly journals The bacterial oxidation of picolinamide, a photolytic product of Diquat

1972 ◽  
Vol 127 (5) ◽  
pp. 819-831 ◽  
Author(s):  
C. G. Orpin ◽  
M. Knight ◽  
W. C. Evans
Keyword(s):  
Molecular Oxygen ◽  
Ultrasonic Treatment ◽  
Substrate Concentration ◽  
Sodium Arsenite ◽  
Culture Media ◽  
High Substrate Concentration ◽  
Bacterial Oxidation ◽  
Gram Negative ◽  
Whole Cells ◽  
Culture Supernatants

The pathway of oxidation of picolinamide (pyridine-2-carboxamide) by a Gram-negative rod has been elucidated. Under conditions of high pH, restricted aeration and high substrate concentration, whole cells released 2,5-dihydroxypyridine into culture supernatants. Sodium arsenite at 5mm caused whole cells to accumulate 6-hydroxypicolinate, and, at 1mm, pyruvate, in culture media. Whole cells oxidized picolinamide, picolinate, 6-hydroxypicolinate, maleamate and maleate without lag. Cell-free extracts converted picolinamide into picolinate, and hydroxylated picolinate to 6-hydroxypicolinate. The hydroxylase was particulate, but could be solubilized by ultrasonic treatment; it required NAD+ for activity, and did not require molecular oxygen. 2,5-Dihydroxypyridine was converted into maleamate and formate by an oxygenase requiring GSH and Fe2+. Maleamate was deamidated to maleate, and maleate isomerized to fumarate, by unsupplemented extracts.

scholarly journals The bacterial oxidation of N-methylisonicotinate, a photolytic product of Paraquat

1972 ◽  
Vol 127 (5) ◽  
pp. 833-844 ◽  
Author(s):  
C. G. Orpin ◽  
M. Knight ◽  
W. C. Evans
Keyword(s):  
Enzyme System ◽  
Soluble Enzyme ◽  
Bacterial Oxidation ◽  
Gram Negative ◽  
Whole Cells ◽  
Photodegradation Product ◽  
Enzyme Systems ◽  
A Cell ◽  
Methyl Derivatives ◽  
Bacterium Strain

Two bacteria have been isolated that are capable of oxidizing N-methylisonicotinate, a photodegradation product of Paraquat (1.1′-dimethyl-4,4′-bipyridylium ion). N-Methylisonicotinate-grown cells of strain 4C1, a Gram-positive rod, oxidized 2-hydroxy-N-methylisonicotinate without lag. Cell-free extracts of these cells converted 2-hydroxyisonicotinate into 2,6-dihydroxyisonicotinate; the reaction did not require molecular oxygen. Maleamate was deamidated and maleate isomerized to fumarate by soluble enzyme systems. [14C]Formaldehyde was isolated as the dimedone derivative from the supernatant of a cell suspension oxidizing N-[14C]methylisonicotinate, and no [14C]-methylamine was detected. Whole cells incubated with N-methyl[carboxy-14C]isonicotinate released 95% of the radioactivity as 14CO2. The second bacterium, strain 4C2, a Gram-negative rod, did not oxidize any of the mono- or di-hydroxypyridines or their N-methyl derivatives that were available or could be synthesized; nor did cell-free extracts oxidize any of these compounds. Methylamine was oxidized by whole cells without lag; cell-free extracts converted methylamine into formaldehyde when a soluble enzyme system requiring an electron acceptor was used; formaldehyde was oxidized to formate and formate to CO2 by enzyme systems requiring NAD+.

scholarly journals Assessment of native cadmium-resistant bacteria in cacao (Theobroma cacao L.) - cultivated soils

2021 ◽  
Author(s):  
Henry A. Cordoba-Novoa ◽  
Jeimmy A. Cáceres-Zambrano ◽  
Esperanza Torres-Rojas
Keyword(s):  
Theobroma Cacao ◽  
Culture Media ◽  
Resistant Bacteria ◽  
High Ability ◽  
Polluted Soils ◽  
Soil Diversity ◽  
Gram Negative ◽  
Molecular Analyses ◽  
Theobroma Cacao L ◽  
Cultivated Soils

Traces of cadmium (Cd) have been reported in some chocolate products due to soils with Cd and the high ability of cacao plants to extract, transport, and accumulate it in their tissues. An agronomic strategy to minimize the uptake of Cd by plants is the use of cadmium-resistant bacteria (Cd-RB). However, knowledge about Cd-RB associated with cacao soils is scarce. This study was aimed to isolate and characterize Cd-RB associated with cacao-cultivated soils in Colombia that may be used in the bioremediation of Cd-polluted soils. Diversity of culturable Cd-RB, qualitative functional analysis related to nitrogen, phosphorous, carbon, and Cd were performed. Thirty different Cd-RB morphotypes were isolated from soils with medium (NC, Y1, Y2) and high (Y3) Cd concentrations using culture media with 6 mg Kg-1 Cd. Cd-RB were identified based on morphological and molecular analyses. The most abundant morphotypes (90%) were gram-negative belong to Phylum Proteobacteria and almost half of them showed the capacity to fix nitrogen, solubilize phosphates and degrade cellulose. Unique morphotypes were isolated from Y3 soils where Burkholderia and Pseudomonas were the dominant genera indicating their capacity to resist high Cd concentrations. P. putida GB78, P. aeruginosa NB2, and Burkholderia sp. NB10 were the only morphotypes that grew on 18 up to 90 (GB78) and 140 mg Kg-1 Cd (NB2-NB10); however, GB78 showed the highest Cd bioaccumulation (5.92 mg g-1). This study provides novel information about culturable Cd-RB soil diversity with the potential to develop biotechnology-based strategies.

Enhanced thermostability and tolerance of high substrate concentration of an esterase by directed evolution

2004 ◽  
Vol 27 (4-6) ◽  
pp. 169-175 ◽  
Author(s):  
Ji-Heui Kim ◽  
Gi-Sub Choi ◽  
Seung-Bum Kim ◽  
Won-Ho Kim ◽  
Jin-Young Lee ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Substrate Concentration ◽  
High Substrate Concentration ◽  
High Substrate

scholarly journals N-Halosuccinimides as Precatalysts for C-, N-, O-, and X-Nucleophilic Substitution Reactions of Alcohols under Mild Reaction Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 460
Author(s):  
Njomza Ajvazi ◽  
Stojan Stavber
Keyword(s):  
Nucleophilic Substitution ◽  
Substrate Concentration ◽  
Solvent Free ◽  
Substitution Reactions ◽  
High Substrate Concentration ◽  
Reaction Conditions ◽  
High Substrate ◽  
Nucleophilic Substitution Reactions ◽  
Solvent Free Reaction

N-halosuccinimides (chloro, bromo, and iodo, respectively) were introduced, tested, and applied as efficient and non-metal precatalysts for C-, N-, O-, and X-nucleophilic substitution reactions of alcohols under solvent-free reaction conditions (SFRC) or under high substrate concentration reaction conditions (HCRC) efficiently and selectively, into the corresponding products.

The effects of phospholipid depletion on the cleavage pattern of the cell walls of frozen Gram-negative bacteria

1973 ◽  
Vol 19 (8) ◽  
pp. 1056-1057 ◽  
Author(s):  
A. Forge ◽  
J. W. Costerton
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cytoplasmic Membrane ◽  
Gram Negative Bacteria ◽  
Cleavage Pattern ◽  
Gram Negative ◽  
Whole Cells ◽  
The Cross ◽  
Double Track ◽  
Chloroform Methanol

Extraction of whole cells of the marine pseudomonad (B-16) with chloroform–methanol causes the disappearance of the cleavage planes, and the cross-sectioned profile of both the cytoplasmic membrane and the double-track layer of the cell wall.

scholarly journals Synthesis and oxidation of aminoalkyl-onium compounds by pig kidney diamine oxidase

1971 ◽  
Vol 122 (4) ◽  
pp. 557-567 ◽  
Author(s):  
W. G. Bardsley ◽  
J. S. Ashford ◽  
C. M. Hill
Keyword(s):  
Substrate Concentration ◽  
Diamine Oxidase ◽  
Amino Group ◽  
High Substrate Concentration ◽  
High Substrate ◽  
Pig Kidney ◽  
Substrate Interaction ◽  
Enzyme Substrate ◽  
Potent Inhibition

1. The preparation of a series of compounds derived from diamines by replacing one amino group by a dimethylsulphonium, isothiuronium, trimethylammonium, NN′-dimethylimidazolium or N-methylpyridinium species is described. 2. The behaviour of these compounds as substrates of pig kidney diamine oxidase is reported. All but the trimethylammonium compounds proved to be substrates. 3. Many of these compounds showed potent inhibition at high substrate concentration and this was studied. 4. On the basis of these and other observations a scheme for enzyme–substrate interaction is suggested.

Resolution of rat renin substrates by isoelectric focusing

1977 ◽  
Vol 55 (8) ◽  
pp. 869-875 ◽  
Author(s):  
A. A. Faiers ◽  
A. Y. Loh ◽  
D. H. Osmond
Keyword(s):  
Isoelectric Focusing ◽  
Substrate Concentration ◽  
Rat Plasma ◽  
The Other ◽  
Multiple Forms ◽  
High Substrate Concentration ◽  
Broad Distribution ◽  
Renin Substrate ◽  
Isoelectric Points ◽  
Different Sources

Pooled plasmas from normal or binephrectomized rats and perfusates of isolated livers were used as sources of renin substrate for isoelectric focusing. After desalting, preliminary fractionation (plasma only), and concentration, the preparations were focused in a pH 3–10 gradient on 20-cm glass plates layered with Sephadex slurry. The pH 4–6 region, containing all the substrate, was scraped from this plate and refocused in a pH 4–6 gradient. Substrate content of 1-cm strips of slurry from half of the plate was determined by both radioimmunoassay and bioassay of angiotensin resulting from incubation with added renin. Corresponding strips from the other half of the plate were incubated without renin as a control for any preformed angiotensin. The asymmetry and broad distribution (pH 4–5) of substrate from different sources suggested the existence of more than one form. Higher resolution achieved by using the high substrate concentration of postnephrectomy plasma and 0.5-cm strips of slurry on 20-cm or 40-cm plates revealed peaks and shoulders of substrate activity. Our data suggest that multiple forms of substrate are synthesized by the liver and circulate in plasma. Postnephrectomy rat plasma appears to contain relatively more substrate(s) with higher isoelectric points than in normal plasma, possibly an accumulation of forms ordinarily degraded by endogenous renal renin.

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