New Bacillus subtilis Strains as Promising Probiotics

© 2018, Pleiades Publishing, Ltd. The properties of new B. subtilis strains GM2 and GM5, isolated from potato rhizosphere and possessing high antimicrobial activity, were studied. The potential of the strains for their use as probiotics was characterized. The strains were resistant to bile and to a wide range of the ambient pH. B. subtilis strains GM2 and GM5 possessed proteolytic and phytate-hydrolyzing activity and proved to be safe for model animals. The strains were characterized by antagonistic properties against phytopathogenic micromycetes, as well as against pathogenic and opportunistic enterobacteria. B. subtilis GM2 and GM5 were concluded to be promising strains for use as probiotics

Specific inhibition of acetylcholinesterase as an approach to decrease muscarinic side effects during myasthenia gravis treatment

© 2017 The Author(s). Non-selective inhibitors of cholinesterases (ChEs) are clinically used for treatment of myasthenia gravis (MG). While being generally safe, they cause numerous adverse effects including induction of hyperactivity of urinary bladder and intestines affecting quality of patients life. In this study we have compared two ChEs inhibitors, a newly synthesized compound C547 and clinically used pyridostigmine bromide, by their efficiency to reduce muscle weakness symptoms and ability to activate contractions of urinary bladder in a rat model of autoimmune MG. We found that at dose effectively reducing MG symptoms, C547 did not affect activity of rat urinary bladder. In contrast, at equipotent dose, pyridostigmine caused a significant increase in tonus and force of spontaneous contractions of bladder wall. We also found that this profile of ChEs inhibitors translates into the preparation of human urinary bladder. The difference in action observed for C547 and pyridostigmine we attribute to a high level of pharmacological selectivity of C547 in inhibiting acetylcholinesterase as compared to butyrylcholinesterase. These results raise reasonable hope that selective acetylcholinesterase inhibitors should show efficacy in treating MG in human patients with a significant reduction in adverse effects related to hyperactivation of smooth muscles

Metallomicellar Systems Based on the Complexes of 1-Hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane Bromide with Transition Metal Nitrates

© 2018, Pleiades Publishing, Ltd. Potentiometry, fluorimetry, dynamic light scattering, and transmission electron microscopy were used to study the aggregation properties of the complexes 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with transition metal nitrates [Cu(II), Ni(II), Co(II), and La(III)]. The critical micelle concentrations, aggregation numbers, the degree of counterion binding to micelles, the size of aggregates, and electrokinetic potentials were determined. The complexes exhibited a high antimicrobial activity, and some of them proved to be more potent than the reference drugs

Blockade of Metabotropic GABA-B Receptors as an Approach to Reduce Toxic Peripheral Effects of Cholinesterase Inhibitors

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The application of organophosphate (OP) pesticides in agriculture, in addition to the existence of chemical warfare nerve agents and their possible use in terrorist acts is a significant threat to populations all over the world. Moreover, treatment of OP poisoning is still imperfect. Here, we studied the effect of blockade of metabotropic GABA-B receptors by compound CGP55845 (10 μM) on the force of muscle contractions when cholinesterases are inhibited by paraoxon. It was shown that CGP55845 prevented the decrease in the force of diaphragm muscle contractions caused by paraoxon ex vivo. Moreover, for in vivo experiments, GABA-B receptor blocker CGP36742 at the doses 30 and 100 mg/kg was used. It was shown that CGP36742 is able to reduce the lethality of mice after OP challenge. Thus, GABA-B receptor blockers can be considered as additional medications, which can complement the current therapy of acute poisoning by cholinesterase inhibitors

Blockade of Metabotropic GABA-B Receptors as an Approach to Reduce Toxic Peripheral Effects of Cholinesterase Inhibitors

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The application of organophosphate (OP) pesticides in agriculture, in addition to the existence of chemical warfare nerve agents and their possible use in terrorist acts is a significant threat to populations all over the world. Moreover, treatment of OP poisoning is still imperfect. Here, we studied the effect of blockade of metabotropic GABA-B receptors by compound CGP55845 (10 μM) on the force of muscle contractions when cholinesterases are inhibited by paraoxon. It was shown that CGP55845 prevented the decrease in the force of diaphragm muscle contractions caused by paraoxon ex vivo. Moreover, for in vivo experiments, GABA-B receptor blocker CGP36742 at the doses 30 and 100 mg/kg was used. It was shown that CGP36742 is able to reduce the lethality of mice after OP challenge. Thus, GABA-B receptor blockers can be considered as additional medications, which can complement the current therapy of acute poisoning by cholinesterase inhibitors

Enhancement of mouse diaphragm contractility in the presence of antagonists of GABA<inf>A</inf> and GABA<inf>B</inf> receptors

© 2019 The Authors. Experimental Physiology © 2019 The Physiological Society New Findings: What is the central question of this study? Do GABA receptors play any role at the neuromuscular junction? What is the main finding and its importance? In the presence of either ionotropic or metabotropic GABA receptor antagonists, diaphragm muscle force production elicited by stimulating the motor nerve at ≥50 Hz was increased. Our data indicate the presence of GABAergic signalling at the neuromuscular junction. Abstract: Despite the signalling role of GABA in the brain and spinal cord, the role of this molecule in the peripheral nervous system and, in particular, at the neuromuscular junction remains practically unexplored. In the present work, the force of mouse diaphragm contractions was measured in the presence of blockers of metabotropic GABAB receptors (CGP 55845) and ionotropic GABAA receptors (picrotoxin) with various patterns of indirect and direct stimulation of muscle by trains of 40 pulses delivered at 10, 20, 50 and 70 Hz. It was found that neither blocker affected the diaphragm contractility caused by indirect stimulation through the motor nerve at 10 and 20 Hz. However, when the stimulation frequency was increased to 50 or 70 Hz, the force of subsequent contractions in the train (when compared with the amplitude of contraction in response to the first pulse) was increased by both CGP 55845 and picrotoxin. With direct stimulation of the diaphragm, no significant changes in the contraction force were detected at any frequency used. The results obtained support the following conclusions: (i) pharmacological inhibition of GABA receptors increases the contractile activity of skeletal muscle; and (ii) frequency-dependent enhancement of GABA receptor activation takes place in the region of the neuromuscular junction

Enhancement of mouse diaphragm contractility in the presence of antagonists of GABA<inf>A</inf> and GABA<inf>B</inf> receptors

© 2019 The Authors. Experimental Physiology © 2019 The Physiological Society New Findings: What is the central question of this study? Do GABA receptors play any role at the neuromuscular junction? What is the main finding and its importance? In the presence of either ionotropic or metabotropic GABA receptor antagonists, diaphragm muscle force production elicited by stimulating the motor nerve at ≥50 Hz was increased. Our data indicate the presence of GABAergic signalling at the neuromuscular junction. Abstract: Despite the signalling role of GABA in the brain and spinal cord, the role of this molecule in the peripheral nervous system and, in particular, at the neuromuscular junction remains practically unexplored. In the present work, the force of mouse diaphragm contractions was measured in the presence of blockers of metabotropic GABAB receptors (CGP 55845) and ionotropic GABAA receptors (picrotoxin) with various patterns of indirect and direct stimulation of muscle by trains of 40 pulses delivered at 10, 20, 50 and 70 Hz. It was found that neither blocker affected the diaphragm contractility caused by indirect stimulation through the motor nerve at 10 and 20 Hz. However, when the stimulation frequency was increased to 50 or 70 Hz, the force of subsequent contractions in the train (when compared with the amplitude of contraction in response to the first pulse) was increased by both CGP 55845 and picrotoxin. With direct stimulation of the diaphragm, no significant changes in the contraction force were detected at any frequency used. The results obtained support the following conclusions: (i) pharmacological inhibition of GABA receptors increases the contractile activity of skeletal muscle; and (ii) frequency-dependent enhancement of GABA receptor activation takes place in the region of the neuromuscular junction

Protective effects of m-(tert-butyl) trifluoroacetophenone, a transition state analogue of acetylcholine, against paraoxon toxicity and memory impairments

m-(Tert-butyl) trifluoroacetophenone (TFK), a slow-binding inhibitor of acetylcholinesterase (AChE), a transition state analog of acetylcholine, was investigated as a potential neuroprotectant of central and peripheral AChE against organophosphate paraoxon (POX) toxicity. Acute toxicity and pharmacological effects of TFK were investigated on mice and rats. Intraperitoneal administered TFK has low acute toxicity in mice (LD50 ≈ 19 mg/kg). Effects on motor function as investigated by rotarod and open field tests showed that TFK up to 5 mg/kg did not alter motor coordination and stereotypical exploration behavior of mice. Passive avoidance test showed that 1 or 5 mg/kg TFK restored memory impairment in scopolamine-induced Alzheimer's disease-like dementia in rats. Pretreatment of mice with 5 mg/kg TFK, 2–3 h before challenge by 2xLD50 POX provided a modest and short protection against POX toxicity. Futhermore, analysis of POX-induced neuronal degeneration by using fluoro-jade B staining showed that TFK pretreatment, at the dose 5 mg/kg before POX challenge, significantly reduced the density of apoptotic cells in hippocampus and entorhinal cortex of mice. Thus, TFK is capable of reducing POX-induced neurotoxicity

New Bacillus subtilis Strains as Promising Probiotics

© 2018, Pleiades Publishing, Ltd. The properties of new B. subtilis strains GM2 and GM5, isolated from potato rhizosphere and possessing high antimicrobial activity, were studied. The potential of the strains for their use as probiotics was characterized. The strains were resistant to bile and to a wide range of the ambient pH. B. subtilis strains GM2 and GM5 possessed proteolytic and phytate-hydrolyzing activity and proved to be safe for model animals. The strains were characterized by antagonistic properties against phytopathogenic micromycetes, as well as against pathogenic and opportunistic enterobacteria. B. subtilis GM2 and GM5 were concluded to be promising strains for use as probiotics

α-tocopherol, a slow-binding inhibitor of acetylcholinesterase

Acetylcholinesterase (AChE) is reversibly inhibited by α-tocopherol (α-T). Steady state kinetic analysis shows that α-T is a mixed slow-binding inhibitor of type A of human enzyme (Kci = 0.49 μM; Kui = 1.6 μM) with a residence time of 2 min on target. Molecular dynamics (MD) simulations support this mechanism, and indicate that α-T first forms multiple non-specific interactions with AChE surface near the gorge entrance, then binds to the peripheral side with alkylene chain slowly sliding down the gorge, inducing no significant conformational change. α-T slightly modulates the progressive inhibition of AChE by the cyclic organophosphorus, cresyl saligenylphosphate, accelerating the fast pseudo-first order process of phosphorylation. A moderate accelerating effect of α-T on phosphorylation by paraoxon was also observed after pre-incubation of AChE in the presence of α-T. This accelerating effect of α-T on ex vivo paraoxon-induced diaphragm muscle weakness was also observed. The effect of α-T on AChE phosphylation was interpreted in light of molecular modeling results. From all results it is clear that α-T does not protect AChE against phosphylation by organophosphorus