The role of formate for the growth of Rhodococcus opacus UFZ B 408 on pyridine

R. opacus UFZ B 408 is able to use pyridine, a potentially growth-inhibiting substrate, as the sole source of carbon, energy and nitrogen. In a previous publication [1] we reported that with the simultaneous utilization of a second carbon and energy source in carbon-substrate-limited chemostat culture, stable steady states could be achieved at higher dilution rates than with growth on pyridine as the sole substrate. Owing to the higher growth yield during growth on such a substrate mixture, both the specific pyridine consumption rates and the residual pyridine concentrations were lower at similar dilution rates than with growth on pyridine alone. Therefore, the critical growth-inhibitory pyridine concentration was only achieved at a higher dilution rate. With the investigations presented here in carbon-substrate-limited continuous culture, the simultaneous utilization of pyridine and formate by R. opacus UFZ B 408 was studied. The yield coefficient during growth on pyridine as the sole substrate amounted to about 0.55 g dry mass/g pyridine. Theoretically, however, the carbon-metabolism-determined yield coefficient should have been about 0.915 g dry mass/g pyridine. Because of the difference between these two values the conclusion was drawn that pyridine is energetically deficient. That means that during growth on pyridine a part of the substrate was dissimilated to supply the energy required for the incorporation of the pyridine carbon into biomass. Formate cannot be used as a carbon source for growth by R. opacus UFZ B 408. However, with growth on pyridine, formate was oxidized simultaneously. During growth on pyridine/formate mixtures, the yield coefficient could be enhanced up to 0.7 g dry mass/g pyridine. That means that biologically usable energy, generated in the course of the formate oxidation, was used for the assimilation of pyridine carbon. The increase in the yield coefficient was related to the utilization ratio of formate to pyridine in a linear manner. However, the carbon-metabolism-determined yield coefficient of 0.915 g dry mass/g pyridine could not be achieved. That can be put down to the fact that R. opacus UFZ B 408 possesses only a limited capacity to oxidize externally supplied formate. Because of the limited formate oxidation capacity the probability is low that, with simultaneous utilization of formate, stable steady states could be achieved at substantially higher dilution rates than with growth on pyridine alone. Enzymatic studies revealed the induction of both NAD(P)⁺-linked glutaric dialdehyde dehydrogenase and isocitrate lyase during growth on pyridine. Therefore, the conclusion was drawn that pyridine is metabolized by R. opacus UFZ B 408 via the same pathway described for the utilization of pyridine by Nocardia Z1 [2]. This conclusion implies that the ability to oxidize formate represents a metabolic performance which seems not to be directly related to the pyridine metabolism of R. opacus UFZ B 408.     

Influence of a supplementary carbon source on biodegradation of pyridine by freely suspended and immobilizedPimelobacter sp.

The effect of the presence of supplementary glucose or acetate on the growth and pyridine-degrading activity of freely suspended and calcium-alginate-immobilizedPimelobacter sp. was investigated. Although the supplementary carbon sources could be degraded simultaneously with pyridine,Pimelobacter sp. exhibited a preference for pyridine over supplementary carbon sources. Thus, the pyridine-degrading activity of the freely suspended cells was not decreased significantly by the addition of either glucose (1.5–6 mM) or acetate (6–24 mM) to the pyridine (6–24 mM). In the semi-continuous immobilized cell culture, immobilized cells also exhibited a preference for pyridine over supplementary carbon sources and did not switch their substrate preference throughout the culture. Owing to a high cell concentration, the volumetric pyridine degradation rate at 24 mM pyridine in the immobilized cell culture was approximately six times higher than that in the freely suspended cell culture. Furthermore, the immobilized cells could be reused 16 times without losing their pyridine-degrading activity during the culture period tested. Taken together, the use of immobilizedPimelobacter sp. for the degradation of pyridine is quite feasible because of the preference for pyridine over supplementary carbon sources, the high volumetric pyridine degradation rate, and the reusability of immobilized cells.     

Microbial degradation of pyridine and α-picoline using a strain of the genera <Emphasis Type="Italic">Pseudomonas</Emphasis> and <Emphasis Type="Italic">Nocardia</Emphasis> sp.

Biodegradation of pyridine and α-picoline (2-methyl pyridine) by Pseudomonas pseudoalcaligenes-KPN and Nocardia sp. isolated from garden soil were investigated in batch culture experiments. Pyridine and α-picoline (50–200 mg L⁻¹) were used as sole source of carbon and energy in the investigation. The kinetic constants were evaluated for pyridine and α-picoline degradation under optimized nutritional (C, N, P) and environmental (pH, temperature) conditions. The values of bio-kinetic constant obtained in the present investigation indicate the usefulness of both the cultures for treatment of waste containing pyridine and its derivatives.     

Simultaneous utilization of pyridine and fructose by Rhodococcus opacus UFZ B 408 without an external nitrogen source

 A bacterium classified as Rhodococcus opacus, which is able to use pyridine (a potentially growth-inhibiting substrate) as its sole source of carbon, energy and nitrogen, was isolated. In a carbon-limited chemostat culture, the kinetics was determined for growth on both pyridine and a mixture of pyridine and fructose (9 mM/22.15 mM). With growth on pyridine, stable steady states were achieved up to dilution rates of about 0.1 h^-1. A further increase in the dilution rate resulted in the progressive accumulation of pyridine in the culture liquid and the cells were washed out. The maximum specific growth rate (μ_max = 0.23 h^-1) and the K _S value (0.22 mM) for growth on pyridine were determined from the residual pyridine concentrations measured within the range of stable steady states. With growth on the substrate mixture, the specific pyridine consumption rates and the residual pyridine concentrations were lower at similar dilution rates than with growth on pyridine alone, and stable steady states were established at dilution rates of up to 0.13 h^-1. The maximum pyridine degradation rate was enhanced to 270 mg pyridine l^-1 h^-1 compared to 210 mg pyridine l^-1 h^-1with growth on pyridine as a single substrate. An external nitrogen source did not need to be added in the case of growth on the substrate mixture. Fructose was assimilated by means of ammonium released from pyridine. Analysis of the nitrogen balance furnished proof that pyridine is an energy-deficient substrate; pyridine was assimilated and dissimilated at a ratio of 1 mol/0.67 mol respectively. The resulting yield coefficient was about 0.55 g dry weight/g pyridine. Moreover, it was demonstrated that, in regard to the biologically usable energy, 1 mol pyridine corresponds to 0.43 mol fructose. Received: 3 July 1995/Received revision: 19 October 1995/Accepted: 24 October 1995     

Isolation and characterization of potential aerobic bacteria capable for pyridine degradation in presence of picoline,phenol and formaldehyde as co-pollutants

Pyridine, heterocyclic aromatic compound is known to be toxic, carcinogenic and teratogenic to several living organisms. In this study, two aerobic bacteria ITRCEM1 and ITRCEM2 capable for pyridine degradation were isolated and characterized as Bacillus cereus (DQ435020) and Alcaligenes faecalis (DQ435021), respectively. For pyridine degradation, mixed bacterial culture was found more effective compared to axenic culture ITRCEM1 and ITRCEM2 degrading 94.23, 67.84, and 83.35% pyridine, respectively, at 144 h incubation period at pH 7.0 ± 0.1, temp 37 ± 2°C and shaking rate 125 rpm in MSM containing 1% glucose and 0.2% peptone as carbon and nitrogen source, respectively. The presence of phenol and formaldehyde in MSM has shown inhibitory effect on pyridine degradation whereas picoline has favored the bacterial growths and pyridine degradation. Further, the HPLC analysis has shown the reduction in peaks compared to controls, indicating that reduction in peak area might be largely attributed to the bacterial degradation of pyridine by bacterial catabolic enzymes.     

Microbial degradation and metabolic pathway of pyridine by a <Emphasis Type="Italic">Paracoccus</Emphasis> sp. strain BW001

A bacterial strain using pyridine as sole carbon, nitrogen and energy source was isolated from the activated sludge of a coking wastewater treatment plant. By means of morphologic observation, physiological characteristics study and 16S rRNA gene sequence analysis, the strain was identified as the species of Paracoccus. The strain could degrade 2,614 mg l⁻¹ of pyridine completely within 49.5 h. Experiment designed to track the metabolic pathway showed that pyridine ring was cleaved between the C₂ and N, then the mineralization of the carbonous intermediate products may comply with the early proposed pathway and the transformation of the nitrogen may proceed on a new pathway of simultaneous heterotrophic nitrification and aerobic denitrification. During the degradation, NH₃-N occurred and increased along with the decrease of pyridine in the solution; but the total nitrogen decreased steadily and equaled to the quantity of NH₃-N when pyridine was degraded completely. Adding glucose into the medium as the extra carbon source would expedite the biodegradation of pyridine and the transformation of the nitrogen. The fragments of nirS gene and nosZ gene were amplified which implied that the BW001 had the potential abilities to reduce NO₂ ⁻ to NO and/or N₂O, and then to N₂.     

Simultaneous biodegradation of pyridine and quinoline by two mixed bacterial strains

Experiments were conducted to provide data on the effectiveness of bioaugmentation in the removal of pyridine and quinoline from different wastewaters. A pyridine-degrading bacterial strain (Paracoccus sp. BW001) and a quinoline-degrading strain (Pseudomonas sp. BW003) were isolated from the activated sludge of a coking wastewater treatment plant. In this study, a consortium of these two bacterial strains was used as inoculum to simultaneously degrade pyridine and quinoline in three types of wastewaters: sterile synthetic, domestic, and industrial. In addition, variation of the bacterial community structures during degradation was monitored by denaturing gradient gel electrophoresis and amplicon length heterogeneity polymerase chain reaction techniques. The results of our experiments indicate that pyridine and quinoline can be removed efficiently using this inoculum but that the degradation process results in the production of ammonium as a by-product. Also, in the two actual wastewaters investigated, we observed that several autochthonous strains of bacteria in both the domestic and industrial wastewater were tolerant of pyridine and quinoline and grew rapidly.     

Effect of pyridine homologues on the basal rate of electron transport and H+/e − ratio in chloroplasts

Low concentrations of hydrophobic pyridine homologues (1 mM) were found to increase the rate of the Hill reaction in chloroplasts without significantly affecting either the steady-state proton uptake or the rate of proton leakage in the dark. By assuming that the organic base can be bound to two types of independent binding sites in the thylakoid membrane with dissociation constantsK ₁ andK ₂ respectively, the kinetic data can be treated quantitatively. The values ofK ₁ andK ₂ determined by the treatment are in the same relative order as the hydrophobicities of the pyridine homologues:K ₁=1.16 mM andK ₂=54 mM for pyridine; 0.6 and 38 mM for 4-picoline; 0.27 and 31 mM for 4-ethylpyridine, 0.10 and 4.2 mM for 4-t-butylpyridine; 0.08 and 3.2 mM for 4-n-butylpyridine. The rates of oxygen generation and proton uptake by illuminated chloroplasts with either ferricyanide or 1,4-benzoquinone as the electron acceptor were also measured in the presence of various pyridine homologues. Low concentration of pyridine homologues were found to decrease the H⁺/e ^– ratio. This last observation seems to substantiate an indirect coupling mechanism between electron transport and proton translocation.Abbreviations Chl chlorophyll - CF₀ - CF₁ the coupling factor complex of chloroplast - FCCP carbonylcyanide-p-trifluoromethoxyphenylhydrazone - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - Tricine N-tris-(hydroxymethyl)methylglycine     

Pyridine alkaloid distribution in the hoplonemertines

Hoplonemertines possess a family of pyridine compounds affecting the nervous system (Kem, 1985). Anabaseine, the first pyridine to be isolated, stimulates nicotinic receptors. Two other substances, 2,3-bipyridyl and nemertelline (a tetrapyridyl) were isolated from Amphiporus angulatus. In this study samples of 19 species of hoplonemertines were surveyed for the presence of stable pyridines using thin layer chromatography. Pyridines were selectively detected with the Konig reagent.Pyridines were found to be nearly ubiquitous constituents of this taxonomic group. Nevertheless, individual species often differed in the pyridines present as well as the variety of compounds present. A new Konig-reactive pyridine was found in 11 hoplonemertine species. Only Zygonemertes virescens and Amphiporus lactifloreus contained anabasine. Only A. angulatus contained 2,3-bipyridyl and nemertelline. This initial survey suggests that differences in pyridine compositions between hoplonemertines may be a useful taxonomic character.     

8-Aza Analogues of Deaza Purine Nucleosides. Synthesis and Biological Evaluation of 8-Aza-1-deazaadenosine and 2′-Deoxy-8-aza-1-deazaadenosine

Abstract

The syntheses of 7-amino-3-(β-D-ribofuranosyl)-3H-1,2,3-triazolo[4,5-b]pyridine (8-aza-1-deazaadenosine) (2) and 7-amino-3-(2-deoxy-β-D-erythro-pentofuranosyl)-3H-1,2,3-triazolo[4,5-b]pyridine (2′-deoxy-8-aza-1-deazaadenosine) (3) by glycosylation of the anion of 7-chloro-3H-1,2,3-triazolo[4,5-b]pyridine are described. The anomeric configuration as well as the position of glycosylation were determined by ¹H, ¹³ NMR, UV and N.O.E. difference spectroscopy. The cytotoxicity of these nucleosides against several murine and human tumor cell lines is discussed. Compounds 2 and 3 proved to be good inhibitors of adenosine deaminase.     

Electrophysiological properties of pyridine receptors in the crayfish walking leg

Summary Responses of pyridine sensitive units on walking legs of the crayfishOrconectes limosus have been studied using extracellular recording techniques.Post-stimulus-time histograms were established and the mean values of the maximal frequencies were plotted in dose-response curves. The curves can be separated into two groups having a slope of 0.3 and 1 in double logarithmic plots and a sensitivity range of 4 and 2 decades, respectively. This implies two different types of pyridine receptors.Abbreviation vH van Harreveld solution     

Preliminary evidence for a pyridine nucleotide cycle in Bordetella pertussis

Preliminary evidence that Bordetella pertussis has a functional pyridine nucleotide cycle was the observation that [¹⁴C]-nicotinic acid was rapidly metabolized during its uptake by the bacteria to pyridine nucleotides and nicotinamide. Nicotinamide deamidase activity, necessary for the completion of the cycle by conversion of nicotinamide to nicotinic acid, was found in a soluble extract (20000 x g supernatant) of B. pertussis cell lysates.This work was supported by the Science Research Council and Wellcome Research Laboratories.     

Control of the pyridine nucleotide-linked Ca release from mitochondria by respiratory substrates

Oxidation of mitochondrial pyridine nucleotides followed by their hydrolysis promotes Ca²⁺ release from intact liver mitochondria. In most of the previous studies oxidation was achieved with pro-oxidants which were added to mitochondria respiring on succinate in the presence of rotenone, a site I-specific inhibitor of the respiratory chain. Here we investigate pro-oxidant dependent and independent Ca²⁺ release from mitochondria when respiration is supported either by the NAD⁺-linked substrate β-hydroxybutyrate, or by succinate. In the presence, as well as in the absence, of the pro-oxidant t-butylhydroperoxide mitochondria retain Ca²⁺ much better with succinate than with β-hydroxybutyrate, as respiratory substrate. When Ca²⁺ release is induced by t-butylhydroperoxide succinate-supported Ca²⁺ retention is impeded by rotenone. Ca²⁺ release (pro-oxidant dependent or independent) is paralleled by oxidation and hydrolysis of intramitochondrial pyridine nucleotides, and Ca²⁺ retention is paralleled by reduction of pyridine nucleotides. It is concluded that the pyridine nucleotide-linked Ca²⁺ release from mitochondria can be controlled by respiratory substrates which regulate the intramitochondrial hydrolysis of oxidized pyridine nucleotides.     

Biodegradation of pyridine by freely suspended and immobilized Pimelobacter sp.

Freely suspended and Ca-alginate-immobilized cells of Pimelobacter sp. were used for degradation of pyridine. When the pyridine concentration was up to 2 g l^–1, freely suspended cells completely degraded pyridine regardless of the initial cell concentrations used. However, when the pyridine concentration increased to 4 g l^–1, the initial cell concentration in freely suspended cell culture should be higher than 1.5 g dry cell weight l^–1 for complete degradation of pyridine. In addition, a freely suspended cell culture with a high initial cell concentration resulted in a high volumetric pyridine-degradation rate, suggesting the potential use of immobilized cells for pyridine-degradation. When the immobilized cells were used for pyridine-degradation, neither specific pyridine-degradation rate nor tolerance against pyridine was improved. However, a high volumetric pyridine-degradation rate in the range 0.082–0.129 g l^–1 hr^–1 could be achieved by the immobilized cells because of the high cell concentration. Furthermore, when the immobilized cells were reused in degrading pyridine at a concentration of 2–4 g l^–1 they did not lose their pyridine-degrading activity for 2 weeks. Taken together, the data obtained here showed the feasibility of using immobilized cells for pyridine-degradation.     

一株红球菌属细菌LV4在高盐条件下的吡啶降解特性

由微生物介导的吡啶降解技术是解决高盐吡啶环境污染的经济有效方法之一,开发具有吡啶降解性能且能够耐受高盐分的微生物是该类研究的重要前提。本研究从山西太原钢铁公司焦化废水处理厂活性污泥中分离培养了一株耐盐吡啶降解菌,通过菌落形态和16S rDNA基因系统发育分析,鉴定其为红球菌属(Rhodococcus sp.)的细菌。耐盐性实验结果表明,菌株LV4能够在0%–6%盐度范围内生长,并完全降解初始浓度为500 mg/L的吡啶;但当盐度高于4%时,菌株LV4因其生长变缓而导致吡啶完全降解时间明显延长。扫描电镜结果显示,高盐环境会使菌株LV4的菌体细胞分裂变慢,诱导细胞表面分泌更多的颗粒状胞外聚合物(extracellular polymeric substance, EPS)。当盐度不高于4%时菌株LV4主要依靠EPS中蛋白含量的增加来响应高盐环境的冲击。单因素实验优化发现,菌株LV4在盐度为4%的高盐环境中降解吡啶的最佳条件为温度30℃、pH 7.0、转速为120 r/min (DO 10.30 mg/L)。最优条件下菌株LV4对于初始浓度为500 mg/L的吡啶,在经过12 h的适应期后,...     

Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium

Quantum chemical calculations using the density functional theory (B3LYP/6-31G* DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E _HOMO), energy of lowest unoccupied molecular orbital (E _LUMO) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π*) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.     

Fotolisi Dell'Acqua e Riduzione Fotosintetica dei Coenzimi Piridinici in Cuscuta Epithymum

Abstract

Photolysis of water and photosynthetic reduction of pyridine nucleotides in CUSCUTA EPITHYMUM. — The reactions for the photolysis of water appear to be present in extracts prepared from seedlings of C. epithymum but not in the extracts prepared from filaments detached from the host (Trifolium repens). Extracts from both seedlings and filaments fail to catalyze the photosynthetic reduction of pyridine nucleotides. Together with the results previously obtained on the mechanism for the fixation of carbon dioxide, the present data suggest that a complete photosynthetic cycle is absent in this species of dodder.     

Detection of a New Piperideine Alkaloid in the Pygidial Glands of Some Stenus Beetles

Rove beetles of the genus Stenus produce and store bioactive alkaloids like stenusine ( 3 ), 3‐(2‐methylbut‐1‐enyl)pyridine ( 4 ), and cicindeloine ( 5 ) in their pygidial glands to protect themselves from predation and microorganismic infestation. The biosynthesis of stenusine ( 3 ), 3‐(2‐methylbut‐1‐enyl)pyridine ( 4 ), and cicindeloine ( 5 ) was previously investigated in Stenus bimaculatus, Stenus similis, and Stenus solutus, respectively. The piperideine alkaloid cicindeloine ( 5 ) occurs also as a major compound in the pygidial gland secretion of Stenus cicindeloides. The three metabolites follow the same biosynthetic pathway, where the N‐heterocyclic ring is derived from L ‐lysine and the side chain from L ‐isoleucine. The different alkaloids are finally obtained by few modifications of shared precursor molecules, such as 2,3,4,5‐tetrahydro‐5‐(2‐methylbutylidene)pyridine ( 1 ). This piperideine alkaloid was synthesized and detected by GC/MS and GC at a chiral phase in the pygidial glands of Stenus similis, Stenus tarsalis, and Stenus cicindeloides.     

Synthesis and Biological Evaluation of Some D-Arabino- and D-Lyxofuranosyl-Pyridine C-Nucleosides

Abstract

The addition reaction of either 3-bromo-5-lithiopyridine (2a) or 3-cyano-5-lithiopyridine (2b) to 2,3:4,5-di-O-isopropylidene-aldehydo-D-arabinose (1) or 2,4:3,5-di-O-benzylidene-aldehydo-D-lyxose (8) gave respectively a D-gluco/D-manno mixture of 3-bromo- and 3-cyano-5-(2,3:4,5-di-O-isopropylidene-pentitol-1-yl)pyridine (3a,b) or a D-galacto/D-talo mixture of respectively 3-bromo- and 3-cyano-5-(2,4:3,5-di-O-benzylidene-pentitol-1-yl)pyridine (9a,b). Mesylation of C-1′ followed by reaction with CF₃COOH/H₂O resulted in the formation of the corresponding D-arabino- or D-lyxofuranosyl pyridine C-nucleosides. The cyano group of (5b) and (11b) was converted into a carbamoyl group using Amberlite IRA 400 (OH^?). 3-Cyano-5-D-arabinofuianosylpyridine (5b) was converted into 3-thiocarbamoyl-5-D-arabinofuranosyl-pyridine (7) using H₂S and triethylamine.

None of the test compounds showed a marked cytostatic or antiviral activity in vitro.     

Conformations and optical rotatory properties of poly-O-acetylthreonine and poly-O-acetylallothreonine

Optically active poly-O-acetylthreonine and poly-O-acetyl-allothreonine exist in the β form in pyridine, in 2-chloruethanol–dichloromethane mixed solvent., and in the solid state. The optical rotatory dispersion of the β form of poly-O-acetyl-L -threonine in a 2-ehloroethanol–dichlomethane mixture showed a Cotton effect in the 230 mμ region. The ORD data in the visible spectral region fit, the Moffitt. equation. The absolute values of b₀, as measured in pyridine for polypeptides with a molecular weight above 17000, varied in the range 100–200°, the sign depending on the absolute configuration of the side chain.