Commonly used alkylimidazolium ionic liquids are poorly to negligibly biodegradable, and some are toxic, with the potential to poison typical biological test systems. Therefore, when ionic liquids ...are present in technological wastewaters they could break through classical wastewater treatment systems into natural waters and become potentially persistent pollutants. A recent study investigating different advanced oxidation processes found that the H
2O
2/UV system degraded dissolved imidazolium ionic liquids with the greatest efficiency. In the present study, high performance liquid chromatography was coupled with electrospray mass spectrometry to separate, analyse and identify degradation products following the treatment of ionic liquid solutions with H
2O
2 in the presence of UV irradiation. It was found that hydroxylation in short-chain entities occurred mainly within the ring moiety, whereas in the case of longer alkylated cations, oxidation of the alkyl chain yielded several products. The potential transformation products were identified structurally by MS/MS analysis and are discussed in the light of their putative toxicity and biodegradability.
Ionic liquids are widely studied as alternative solvents in organic synthesis and catalysis, in electrochemistry and the separation sciences; with their many applications they will soon be produced ...on an industrial scale. Available toxicological data of ionic liquids have already suggested initial guidelines for the conscious design of safer chemicals. In this study a new group of such redesigned ionic liquids—1-alkoxymethyl-3-hydroxypyridinium cations+acesulphamate, saccharinate and chloride anions—was assayed with respect to their inhibitory activity towards acetylcholinesterase and their cellular toxicity towards the IPC-81 rat promyelocytic leukaemia cell line: the acute biological activity of these compounds is very low. Effective concentrations lie in the millimole range, which is well above possible intracellular concentrations. Only the compounds with the longest alkoxymethyl chain inhibit the enzyme at effective concentrations that are one order of magnitude smaller. No significant differences are observed when the anion compartment in the enzymatic assay is varied. However, the cytotoxicity data show EC
50 for acesulphamates and saccharinates to be higher than the values for the chloride analogues. Also, a slight alkoxymethyl chain length effect on the overall cytotoxicity is discernible. The biodegradability of the 1-alkoxymethyl-3-hydroxypyridinium salts varies from 21% to 72% and depends on the type of anion the cation is linked with. It improves with lengthening alkyl chain, but only in the range from 4 to 11 carbon atoms.
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in ...medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.
The O-polysaccharide of
Salmonella
Telaviv was obtained by mild acid degradation of the lipopolysaccharide and studied by chemical methods (sugar and methylation analyses, Smith degradation, de-
O
...-acetylation) and NMR spectroscopy. The structure of the O-polysaccharide was established. The repeating units that are proximal to the lipopolysaccharide core region mostly have a digalactose side chain and lack glucose, whereas those at the other end of the chain mostly do bear glucose but are devoid of the disaccharide side chain. This is the first structure established for the O-polysaccharide of a
Salmonella
serogroup O:28 (formerly M) strain characterized by subfactors O28
1
and O28
2
. Knowledge of this structure and the structure of the O-polysaccharide of
Salmonella
Dakar (O28
1
, O28
3
) established earlier is crucial for determination of the exact structures associated with subfactors O28
1
, O28
2
, and O28
3
and elucidation of the genetic basis of the close relationship between
Escherichia coli
O71 and
S. enterica
O:28 O-antigens.
Growth of Ruta graveolens shoots was induced when Bacillus sp. cell lysates were added to the culture medium. Elicitation of coumarin by this lysate was also very effective; the concentrations of ...isopimpinelin, xanthotoxin and bergapten increased to 610, 2120 and 1460 μg g-¹ dry wt, respectively. It also had a significant effect on the production of psoralen and rutamarin (680 and 380 μg g-¹ dry wt) and induced the biosynthesis of chalepin, which was not detected in the control sample, up to 47 μg g-¹ dry wt With lysates of the Pectobacterium atrosepticum, their effect on growth was not so significant and had no effect on the induction of coumarin accumulation. But elicitation with this lysate was much more effective for inducing the production of furoquinolone alkaloids; the concentrations of γ-fagarine, skimmianine, dictamnine and kokusaginine rose to 99, 680, 172 and 480 μg g-¹ dry wt, respectively.
Pseudomonads are metabolically flexible and can thrive on different plant hosts. However, the metabolic adaptations required for host promiscuity are unknown. Here, we addressed this knowledge gap by ...employing RNAseq and comparing transcriptomic responses of Pseudomonas donghuensis P482 to root exudates of two plant hosts: tomato and maize. Our main goal was to identify the differences and the common points between these two responses. Pathways upregulated only by tomato exudates included nitric oxide detoxification, repair of iron-sulfur clusters, respiration through the cyanide-insensitive cytochrome bd, and catabolism of amino and/or fatty acids. The first two indicate the presence of NO donors in the exudates of the test plants. Maize specifically induced the activity of MexE RND-type efflux pump and copper tolerance. Genes associated with motility were induced by maize but repressed by tomato. The shared response to exudates seemed to be affected both by compounds originating from the plants and those from their growth environment: arsenic resistance and bacterioferritin synthesis were upregulated, while sulfur assimilation, sensing of ferric citrate and/or other iron carriers, heme acquisition, and transport of polar amino acids were downregulated. Our results provide directions to explore mechanisms of host adaptation in plant-associated microorganisms.
Ochrobactrum spp. are ubiquitous bacteria attracting growing attention as important members of microbiomes of plants and nematodes and as a source of enzymes for biotechnology. Strain Ochrobactrum ...sp. A44T was isolated from the rhizosphere of a field-grown potato in Gelderland, the Netherlands. The strain can interfere with quorum sensing (QS) of Gram-negative bacteria through inactivation of N-acyl homoserine lactones (AHLs) and protect plant tissue against soft rot pathogens, the virulence of which is governed by QS. Phylogenetic analysis based on 16S rRNA gene alone and concatenation of 16S rRNA gene and MLSA genes (groEL and gyrB) revealed that the closest relatives of A44T are O. grignonense OgA9aT, O. thiophenivorans DSM 7216T, O. pseudogrignonense CCUG 30717T, O. pituitosum CCUG 50899T, and O. rhizosphaerae PR17T. Genomes of all six type strains were sequenced, significantly expanding the possibility of genome-based analyses in Ochrobactrum spp. Average nucleotide identity (ANIb) and genome-to-genome distance (GGDC) values for A44T and the related strains were below the single species thresholds (95% and 70%, respectively), with the highest scores obtained for O. pituitosum CCUG 50899T (87.31%; 35.6%), O. rhizosphaerae PR17T (86.80%; 34.3%), and O. grignonense OgA9aT (86.30%; 33.6%). Distinction of A44T from the related type strains was supported by chemotaxonomic and biochemical analyses. Comparative genomics revealed that the core genome for the newly sequenced strains comprises 2731 genes, constituting 50-66% of each individual genome. Through phenotype-to-genotype study, we found that the non-motile strain O. thiophenivorans DSM 7216T lacks a cluster of genes related to flagella formation. Moreover, we explored the genetic background of distinct urease activity among the strains. Here, we propose to establish a novel species Ochrobactrum quorumnocens, with A44T as the type strain (= LMG 30544T = PCM 2957T).
Abstract
Four Dactylorhiza taxa in the D. incarnata/maculata complex were examined to identify differences in floral traits, using micromorphological, histochemical and ultrastructural studies on ...spur and labellum structure. Flowers were collected at anthesis from four monospecific populations in Gdańsk, Pomerania, northern Poland. The flowers revealed secretory activity of the epidermis of the spur mouth (possible osmophores) and of the inner epidermis of spurs (possible nectar traces) in D. incarnata, D. maculata subsp. fuchsii and D. majalis subsp. majalis. The secretion was absent on papillae in D. maculata subsp. maculata. However, the presence of slightly developed micro-channels, vesicles in periplasmic space and plastoglobuli in plastids may be responsible for production of a meagre amount of fragrance or nectar. The examined Dactylorhiza taxa were also clearly separated by their scent profiles. The most abundant class of compounds is based on the common structure of 4-hydroxybenzene. The presence of vanillin precursors, such as 4-hydroxybenzaldehyde, which, like vanillin, are widely recognized to be important in attracting potential pollinators, was observed mainly in D. incarnata and D. majalis subsp. majalis. The scent compounds were characteristic for a particular species, which may be important for their floral isolation.
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