Search results for "terase"
showing 10 items of 446 documents
Characterization and purification of a bacterial chlorogenic acid esterase detected during the extraction of chlorogenic acid from arbuscular mycorrh…
2016
International audience; A Gram-negative bacterium able to grow using chlorogenic acid (5-caffeoylquinic acid) as sole carbon source has been isolated from the roots of tomato plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. An intracellular esterase exhibiting very high affinity (K-m = 2 mu M) for chlorogenic acid has been extracted and purified by FPLC from the chlorogenate-grown cultures of this bacterium. The molecular mass of the purified esterase determined by SDS-PAGE was 61 kDa and its isoelectric point determined by chromatofocusing was 7.75. The esterase hydrolysed chlorogenic acid analogues (caffeoylshikimate, and the 4- and 3-caffeoylquinic acid i…
Boric acid toxicity to the German cockroach, Blattella germanica: Alterations in midgut structure, and acetylcholinesterase and glutathione S-transfe…
2006
0048-3575 doi: DOI: 10.1016/j.pestbp.2005.05.002; Oral toxicity of boric acid, an inorganic insecticide, was evaluated on German cockroach, Blattella germanica L. (Dictyoptera, Blattellidae). Newly emerged adults were exposed to various concentrations of boric acid incorporated into the diet. Results showed that treated insects exhibited toxic symptoms with a dose-dependent mortality. Histological study of midgut revealed alterations in the epithelial cells and a signiWcant increase in the epithelium thickness. In a second series of experiments, the compound was investigated on the activities of acetylcholinesterase (AChE) and glutathione S-transferases (GSTs). Data showed that the compound…
The antioxidant 2,3‐dichloro,5,8‐dihydroxy,1,4‐naphthoquinone inhibits acetyl‐cholinesterase activity and amyloid β 42 aggregation: A dual target the…
2020
Alzheimer's disease is characterized by amyloid β aggregation and cholinergic neurodegeneration. In the present study, pure DDN (2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone) was examined, for the first time, for its dual potential as inhibitor of acetylcholinesterase (AChE) and Aβ42 aggregation. Such investigation was encouraged by the in vitro high antioxidant potential of DDN. Indeed, it revealed interesting antioxidant activity with IC50 values of 9.8 and 4.3 µM for ABTS and reducing power, respectively. The ability of DDN to counteract Aβ42 aggregation was evaluated by thioflavine-T assay. Strong inhibition of Aβ42 aggregation of more than 90% at 25 µM was measured. Moreover, results …
Effect of methylparaben in Artemia franciscana.
2017
In this study, the toxicity of methylparaben (MeP) an emerging contaminant, was analysed in the sexual species Artemia franciscana, due to its presence in coastal areas and marine saltworks in the Mediterranean region. The acute toxicity (24 h-LC50) of MeP in nauplii was tested and its chronic effect (9 days) evaluated by measuring survival and growth under two sublethal concentrations (0.0085 and 0.017 mg/L). Also, the effect on several key enzymes involved in: antioxidant defences (catalase (CAT) and gluthathion-S-transferase (GST)), neural activity (cholinesterase (ChE)) and xenobiotic biotransformation (carboxylesterase (CbE), was assessed after 48 h under sublethal exposure. The result…
Are mussels able to distinguish underwater sounds? Assessment of the reactions of Mytilus galloprovincialis after exposure to lab-generated acoustic …
2016
This study examined the effects of lab-generated acoustic signals on the behaviour and biochemistry of Mediterranean mussels (Mytilus galloprovincialis). The experiment was carried out in a tank equipped with a video-recording system using six groups of five mussels exposed to five acoustic treatments (each treatment was replicated three times) for 30 min. The acoustic signals, with a maximum sound pressure level of 150 dB rms re 1 μPa, differed in frequency range as follows: low (0.1–5 kHz), mid-low (5–10 kHz), mid (10–20 kHz), mid-high (20–40 kHz) and high (40–60 kHz). The exposure to sweeps did not produce any significant changes in the mussels' behaviour. Conversely, the specimens expos…
Underwater high frequency noise: Biological responses in sea urchin Arbacia lixula (Linnaeus, 1758)
2020
Marine life is extremely sensitive to the effects of environmental noise due to its reliance on underwater sounds for basic life functions, such as searching for food and mating. However, the effects on invertebrate species are not yet fully understood. The aim of this study was to determine the biochemical responses of Arbacia lixula exposed to high-frequency noise. Protein concentration, enzyme activity (esterase, phosphatase and peroxidase) and cytotoxicity in coelomic fluid were compared in individuals exposed for three hours to consecutive linear sweeps of 100 to 200 kHz lasting 1 s, and control specimens. Sound pressure levels ranged between 145 and 160 dB re 1μPa. Coelomic fluid was …
Antioxidant activity and enzymes inhibitory properties of several extracts from two Moroccan Asteraceae species
2018
Abstract The present work reports investigation on phenolic compounds, antioxidant activity and enzyme inhibitory activities (acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase and α-glucosidase) of different extracts from two Moroccan Asteraceae species; Bubonium imbricatum Cav. and Cladanthus arabicus (L.) Cass. B. imbricatum extracts contained the highest amounts of phenolics and flavonoids, and also exhibited higher antioxidant activity. In this species, the highest total phenolic (1611.13 ± 14.23 μmolGAE/gextract) and flavonoid (376.11 ± 8.22 μmolQE/gextract) contents were observed in aqueous-methanol extract obtained by maceration. Further, UHPLC–MS analysis of C. arab…
Firming of fruit tissues by vacuum infusion of pectin methylesterase: Visualisation of enzyme action
2008
; Apple pieces were vacuum-impregnated with either a pectin methylesterase (PME) and calcium solution or with water prior to pasteurization. Pasteurized apple pieces impregnated with PME and calcium showed a significantly higher firmness. Moreover, solid state C-13 NMR spectroscopy of apple cell wall residues revealed an increase of their molecular rigidity. Exogenous PME addition involved a decrease from 82% to 45% of apple pectin degree of methyl-esterification. Microscopic observations of apple slices immunolabelled with antibodies specific for pectins showed that (i) demethyl-esterification was more intense in the cell wall region lining intercellular spaces (demonstrating a key role f…
Type 5 phosphodiesterase (PDE5) and the vascular tree: from embryogenesis to aging and disease
2020
Highlights • Vascular development depends on the timely differentiation of endothelial and smooth muscle cells, that mutually influence their developmental fate. • Endothelial and vascular smooth muscle cell (VSMC) compartments can mutually influence cell and tissue modifications during vascular aging and in vascular disease. • Keeping in mind that PDE5 is mainly expressed in VSMCs, we surveyed the literature on the role of PDE5 in vascular development, aging and disease. • Although most results have been obtained by PDE5 pharmacological inhibition, no data are available, to date, on vascular development, aging or disease following PDE5 genetic ablation.
Acid sphingomyelinase – a regulator of canonical transient receptor potential channel 6 (TRPC6) activity
2019
Recent investigations propose the acid sphingomyelinase (ASM)/ceramide system as a novel target for antidepressant action. ASM catalyzes the breakdown of the abundant membrane lipid sphingomyelin to the lipid messenger ceramide. This ASM‐induced lipid modification induces a local shift in membrane properties, which influences receptor clustering and downstream signaling. Canonical transient receptor potential channels 6 (TRPC6) are non‐selective cation channels located in the cell membrane that play an important role in dendritic growth, synaptic plasticity and cognition in the brain. They can be activated by hyperforin, an ingredient of the herbal remedy St. John’s wort for treatment of de…