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Journal of Bacteriology Jul 2022Staphylococcus aureus Tet38 efflux pump has multiple functions, including conferring resistance to tetracycline and other compounds and enabling internalization and...
Staphylococcus aureus Tet38 efflux pump has multiple functions, including conferring resistance to tetracycline and other compounds and enabling internalization and survival within epithelial cells. In this study, we evaluated the effects of sodium and potassium on expression. These monovalent cations are known to play a role in transport by the related S. aureus TetK and B. subtilis TetL transporters. transcription decreased with increasing sodium concentrations by means of direct repression by the salt stress-dependent KdpD/E regulator. transcription increased 20-fold and tetracycline minimum inhibitory concentration (MIC) increased 4-fold in a Δ mutant. KdpE bound specifically to the promoter. Under extreme salt stress, the survival of S. aureus with intact was reduced compared to that of a Δ mutant. To study the effect of sodium on Tet38 function, we generated constructs overexpressing and and introduced them into Escherichia coli TO114, which is deficient in major sodium transporters. Tet38 tetracycline efflux was directly demonstrated in a fluorescence assay, and tetracycline efflux of both Tet38 and TetK was abolished by the protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP). In contrast, NaCl inhibited efflux by Tet38 but not TetK, whereas KCl inhibited efflux by TetK but not Tet38. Cell-associated Na increased with heterologous overexpression of Tet38. These data indicate that S. aureus Tet38 is a tetracycline efflux pump regulated by the KdpD/E regulator. Under salt stress, S. aureus adjusted its survival in part by reducing the expression of through KdpD/E. The mechanisms by which Tet38 is detrimental to salt tolerance in S. aureus and inhibited by sodium remain to be determined. This study shows that S. aureus Tet38 is a tetracycline efflux pump regulated by KdpD/E regulator. These findings are the first direct demonstration of Tet38-mediated tetracycline efflux, which had previously been inferred from its ability to confer tetracycline resistance. Under salt stress, S. aureus adjusts its survival in part by reducing the expression of through KdpD/E. We demonstrated the differences in the respective functions of S. aureus Tet38 and other tetracycline efflux transporters (S. aureus TetK, B. subtilis TetL) regarding their transport of tetracycline and Na/K. Notably, sodium selectively reduced tetracycline efflux by Tet38, and potassium selectively reduced tetracycline efflux by TetK. The multiple functions of Tet38 emphasize its importance in bacterial adaptation to and survival in diverse environments.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Escherichia coli; Escherichia coli Proteins; Membrane Transport Proteins; Microbial Sensitivity Tests; Potassium; Protein Kinases; Salt Stress; Sodium; Staphylococcus aureus; Tetracycline
PubMed: 35699453
DOI: 10.1128/jb.00142-22 -
Experimental Physiology Sep 2019What is the central question of this study? The traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and...
NEW FINDINGS
What is the central question of this study? The traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation, which does not permit their individual study in different situations. What is the main finding and its importance? We have described a new surgical approach capable of selective denervation of the arterial (aortic and carotid) baroreceptors, keeping the carotid bodies (chemoreceptors) intact. It is understood that this technique might be a useful tool for investigating the relative role of the baro- and chemoreceptors in several physiological and pathophysiological conditions.
ABSTRACT
Studies have demonstrated that the traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation. The present study reports a new surgical approach to denervate the aortic and the carotid baroreceptors selectively, keeping the carotid bodies (peripheral chemoreceptors) intact. Wistar rats were subjected to specific aortic and carotid baroreceptor denervation (BAROS-X) or sham surgery (SHAM). Baroreflex activation was achieved by i.v. administration of phenylephrine, whereas peripheral chemoreflex activation was produced by i.v. administration of potassium cyanide. The SHAM and BAROS-X rats displayed significant hypertensive responses to phenylephrine administration. However, the reflex bradycardia following the hypertensive response caused by phenylephrine was remarkable in SHAM, but not significant in the BAROS-X animals, confirming the efficacy of the surgical procedure to abolish the baroreflex. In addition, the baroreflex activation elicited by phenylephrine increased carotid sinus nerve activity only in SHAM, but not in the BAROS-X animals, providing support to the notion that the baroreceptor afferents were absent. Instead, the classical peripheral chemoreflex hypertensive and bradycardic responses to potassium cyanide were similar in both groups, suggesting that the carotid body chemoreceptors were preserved after BAROS-X. In summary, we describe a new surgical approach in which only the baroreceptors are eliminated, while the carotid chemoreceptors are preserved. Therefore, it is understood that this procedure is potentially a useful tool for examining the relative roles of the arterial baroreceptors versus the chemoreceptors in several pathophysiological conditions, for instance, arterial hypertension and heart failure.
Topics: Animals; Aorta; Arteries; Baroreflex; Blood Pressure; Carotid Body; Chemoreceptor Cells; Denervation; Heart Rate; Hypertension; Male; Phenylephrine; Pressoreceptors; Rats; Rats, Wistar
PubMed: 31161612
DOI: 10.1113/EP087764 -
Life (Basel, Switzerland) Oct 2022Cyanide (CN) pollution in agricultural systems can affect crop production. However, no data are available to describe the full picture of the responsive metabolic...
Cyanide (CN) pollution in agricultural systems can affect crop production. However, no data are available to describe the full picture of the responsive metabolic mechanisms of genes with known functions related to exogenous KCN exposure. In this study, we examined the transcriptome in rice seedlings exposed to potassium cyanide (KCN) using an Agilent 4×44K rice microarray to clarify the relationship between the differentially expressed genes (DEGs) and their function classifications. The number of DEGs (up-regulated genes/down-regulated genes) was 322/626 and 640/948 in the shoots and roots of CN-treated rice seedlings, respectively. Functional predication demonstrated that a total of 534 and 837 DEGs in shoots and roots were assigned to 22 COG categories. Four common categories listed on the top five COG classifications were detected in both rice tissues: signal transduction mechanisms, carbohydrate transport and metabolism, post-translational modification, protein turnover and chaperones, and transcription. A comparison of DEGs aligned to the same COG classification demonstrated that the majority of up-regulated/down-regulated DEGs in rice tissues were significantly different, suggesting that responsive and regulatory mechanisms are tissue specific in CN-treated rice seedlings. Additionally, fifteen DEGs were aligned to three different COG categories, implying their possible multiple functions in response to KCN stress. The results presented here provide insights into the novel responsive and regulatory mechanisms of KCN-responsive genes, and will serve as useful resources for further functional dissections of the physiological significance of specific genes activated in the exogenous KCN stress response in rice plants.
PubMed: 36362856
DOI: 10.3390/life12111701 -
Molecules (Basel, Switzerland) May 2023Fenebrutinib is an orally available Bruton tyrosine kinase inhibitor. It is currently in multiple phase III clinical trials for the management of B-cell tumors and...
Fenebrutinib is an orally available Bruton tyrosine kinase inhibitor. It is currently in multiple phase III clinical trials for the management of B-cell tumors and autoimmune disorders. Elementary in-silico studies were first performed to predict susceptible sites of metabolism and structural alerts for toxicities by StarDrop WhichP450™ module and DEREK software; respectively. Fenebrutinib metabolites and adducts were characterized in-vitro in rat liver microsomes (RLM) using MS3 method in Ion Trap LC-MS/MS. Formation of reactive and unstable intermediates was explored using potassium cyanide (KCN), glutathione (GSH) and methoxylamine as trapping nucleophiles to capture the transient and unstable iminium, 6-iminopyridin-3()-one and aldehyde intermediates, respectively, to generate a stable adducts that can be investigated and analyzed using mass spectrometry. Ten phase I metabolites, four cyanide adducts, five GSH adducts and six methoxylamine adducts of fenebrutinib were identified. The proposed metabolic reactions involved in formation of these metabolites are hydroxylation, oxidation of primary alcohol to aldehyde, n-oxidation, and n-dealkylation. The mechanism of reactive intermediate formation of fenebrutinib can provide a justification of the cause of its adverse effects. Formation of iminium, iminoquinone and aldehyde intermediates of fenebrutinib was characterized. N-dealkylation followed by hydroxylation of the piperazine ring is proposed to cause the bioactivation to iminium intermediates captured by cyanide. Oxidation of the hydroxymethyl group on the pyridine moiety is proposed to cause the generation of reactive aldehyde intermediates captures by methoxylamine. N-dealkylation and hydroxylation of the pyridine ring is proposed to cause formation of iminoquinone reactive intermediates captured by glutathione. FBB and several phase I metabolites are bioactivated to fifteen reactive intermediates which might be the cause of adverse effects. In the future, drug discovery experiments utilizing this information could be performed, permitting the synthesis of new drugs with better safety profile. Overall, in silico software and in vitro metabolic incubation experiments were able to characterize the FBB metabolites and reactive intermediates using the multistep fragmentation capability of ion trap mass spectrometry.
Topics: Rats; Animals; Chromatography, Liquid; Chromatography, High Pressure Liquid; Tandem Mass Spectrometry; Piperazines; Pyridones; Glutathione; Cyanides; Aldehydes; Microsomes, Liver
PubMed: 37241965
DOI: 10.3390/molecules28104225 -
RSC Advances Jul 2022Zorifertinib (AZD-3759; ZFB) is a potent, novel, oral, small molecule used for the treatment of non-small cell lung cancer (NSCLC). ZFB is Epidermal Growth Factor...
Zorifertinib (AZD-3759; ZFB) is a potent, novel, oral, small molecule used for the treatment of non-small cell lung cancer (NSCLC). ZFB is Epidermal Growth Factor Receptor (EGFR) inhibitor that is characterized by good permeability of the blood-brain barrier for (NSCLC) patients with EGFR mutations. The present research reports the profiling of , and reactive metabolites of ZFB. Prediction of vulnerable metabolic sites and reactivity pathways (cyanide and GSH) of ZFB were performed by WhichP450™ module (StarDrop software package) and XenoSite reactivity model (XenoSite Web Predictor-Home), respectively. ZFB metabolites were done by incubation with isolated perfused rat liver hepatocytes and rat liver microsomes (RLMs). Extraction of ZFB and its related metabolites from the incubation matrix was done by protein precipitation. metabolism was performed by giving ZFB (10 mg kg) through oral gavage to Sprague Dawley rats that were housed in metabolic cages. Urine was collected at specific time intervals (0, 6, 12, 18, 24, 48, 72, 96 and 120 h) from ZFB dosing. The collected urine samples were filtered then stored at -70 °C. -Methyl piperazine ring of ZFB undergoes phase I metabolism forming iminium intermediates that were stabilized using potassium cyanide as a trapping agent. Incubation of ZFB with RLMs were performed in the presence of 1.0 mM KCN and 1.0 mM glutathione to check reactive intermediates as it is may be responsible for toxicities associated with ZFB usage. For metabolites there were six phase I metabolites, three phase II metabolites, seven reactive intermediates (four GSH conjugates and three cyano adducts) of ZFB were detected by LC-IT-MS. For metabolites there were six phase I and three phase II metabolites of ZFB were detected by LC-IT-MS. and phase I metabolic pathways were -demethylation, -demethylation, hydroxylation, reduction, defluorination and dechlorination. phase II metabolic reaction was direct sulphate and glucuronic acid conjugation with ZFB.
PubMed: 35919181
DOI: 10.1039/d2ra02848d -
Turkish Journal of Chemistry 2020A study of the electrodeposition of silver from 2 different types of electrolytes; (1) neutral pyrophosphatecyanide electrolyte and (2) alkaline high concentrated...
A study of the electrodeposition of silver from 2 different types of electrolytes; (1) neutral pyrophosphatecyanide electrolyte and (2) alkaline high concentrated cyanide electrolyte in the presence of a variety of additives such as 2-mercaptobenzothiazole, potassium selenocyanate, and potassium antimony tartrate was performed. Influence of additives and cyanide concentration on microstructure and kinetics of the cathodic processes were studied. A brightener couple, 2-mercaptobenzothiazole and potassium antimony tartrate, were combined within this investigation and detected to be highly effective for silver electrodeposition. The rapid increase in current density at the same potential interval related to grain refinement effect of potassium antimony tartrate was shown. The cyclic organic compound, 2-mercaptobenzothiazole, polarizes the reduction to high cathodic potential in pyrophosphate electrolyte. However, the sufficient levelling effect required for the mirror-bright appearance seems to be related to the high polarizing effect of the high concentration cyanide content. In the case of pyrophosphate electrolytes, sufficient levelling cannot be achieved, so semigloss coatings are obtained. The low cathodic potential electrodeposition of silver in pyrophosphate electrolyte, which is found to proceed by 3D instantaneous nucleation, is polarized to high cathodic potentials and grows into 3D progressive nucleation and diffusion-controlled growth in high concentration cyanide electrolyte.
PubMed: 33488164
DOI: 10.3906/kim-1907-80 -
ACS Omega Aug 2023Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent...
Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent consumption, high slurry pH, and environmental hazards. This work aimed to explore the utilization and mechanisms of tannic acid (TA) as an eco-friendly alternative to lime or cyanide in chalcopyrite-pyrite separation. Flotation results showed that TA selectively depressed pyrite yet allowed chalcopyrite to float at neutral or alkaline pH. Adsorption density and zeta potential results indicated that TA adsorbed intensely on pyrite but minorly on chalcopyrite. Besides, potassium ethyl xanthate was still largely adsorbed on chalcopyrite but not on pyrite after TA adsorption. Surface analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy further showed that the oxidation species of FeOOH and Fe (SO), particularly FeOOH were the main active sites for TA chemical adsorption. Owing to the greater and faster oxidation of pyrite, more FeOOH and Fe (SO) were generated on the pyrite surface, and the chemical adsorption of TA was more pronounced on the pyrite surface than on the chalcopyrite surface.
PubMed: 37636951
DOI: 10.1021/acsomega.3c03663 -
Saudi Pharmaceutical Journal : SPJ :... Oct 2023Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative...
Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative flavonoids in onion. Several antioxidant techniques were used in this investigation to assess the antioxidant capabilities of spiraeoside, including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging, N,N-dimethyl-p-phenylenediamine radical (DMPD) scavenging, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS) scavenging activities, cupric ions (Cu) reducing and potassium ferric cyanide reduction abilities. In contrast, the water-soluble α-tocopherol analogue trolox and the conventional antioxidants butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and α-tocopherol were utilized as the standards for evaluation. Spiraeoside scavenged the DPPH radicals an IC of 28.51 μg/mL (r: 0.9705) meanwhile BHA, BHT, trolox, and α-tocopherol displayed IC of 10.10 μg/mL (r: 0.9015), 25.95 μg/mL (r: 0.9221), 7.059 μg/mL (r: 0.9614) and 11.31 μg/mL (r: 0.9642), accordingly. The results exhibited that spiraeoside had effects similar to BHT, but less potent than α-tocopherol, trolox and BHA. Also, inhibitory effects of spiraeoside were evaluated toward some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II) and α-glycosidase, which are related to a number of illnesses, such as Alzheimer's disease (AD), diabetes mellitus and glaucoma disorder. Spiraeoside exhibited IC values of 4.44 nM (r: 0.9610), 7.88 nM (r: 0.9784), 19.42 nM (r: 0.9673) and 29.17 mM (r: 0.9209), respectively against these enzymes. Enzyme inhibition abilities were compared to clinical used inhibitors including acetazolamide (for CA II), tacrine (for AChE and BChE) and acarbose (for α-glycosidase). Spiraeoside demonstrated effective antioxidant, anticholinergic, antidiabetic and antiglaucoma activities. With these properties, it has shown that Spiraeoside has the potential to be a medicine for some metabolic diseases.
PubMed: 37693735
DOI: 10.1016/j.jsps.2023.101760 -
PloS One 2020This study aims to provide basic data on the types and frequency of chemical ingestions and the clinical outcomes of chemical ingestion injury.
OBJECTIVE
This study aims to provide basic data on the types and frequency of chemical ingestions and the clinical outcomes of chemical ingestion injury.
METHODS
This study retrospectively analyzed the data obtained from the Emergency Department-Based Injury In-depth Surveillance of the Korea Centers for Disease Control and Prevention (South Korea) from 2011 to 2016. Patients ingesting chemicals aged ≥ 18 years were included, but those ingesting unknown chemical substances or with unknown clinical outcomes were excluded.
RESULTS
This study included 2,712 (47.2% were men and 52.8% were women, mean age, 47.05 years) patients ingesting chemicals. Unintentional and intentional ingestions were reported in 1,673 (61.7%) and 1,039 (38.3%), respectively. The most commonly ingested chemical substances were hypochlorites, detergents, ethanol, and acetic acid. In the unintentional ingestion group, the most common chemicals upon admission were hypochlorites (74), glacial acetic acid (60), and detergent (33). The admission rates were 60% for glacial acetic acid, 58.3% ethylene glycol, and 30.4% other alkali agents. In the intentional ingestion group, the most common chemicals upon admission were hypochlorites (242), glacial acetic acid (79), ethylene glycol (42), and detergent (41). The admission rates were 91.9% for glacial acetic acid, 87.5% ethylene glycol, 85.7% potassium cyanide, and 81.4% hydrochloric acid. In total, 79 deaths (10 unintentional ingestions, 69 intentional ingestion) were reported, and glacial acetic acid had an odds ratio of 9.299 for mortality.
CONCLUSION
We compared the intentional and unintentional ingestion groups, and analyzed the factors affecting hospital admission and mortality in each group. The types and clinical outcomes of chemical ingestion varied depending on the purpose of chemical ingestion. The findings are considered beneficial in establishing treatment policies for patients ingesting chemicals.
Topics: Acetic Acid; Adolescent; Adult; Aged; Aged, 80 and over; Antidotes; Detergents; Eating; Emergency Service, Hospital; Ethanol; Ethylene Glycol; Female; Hazardous Substances; Humans; Hypochlorous Acid; Male; Middle Aged; Poison Control Centers; Poisoning; Republic of Korea; Young Adult
PubMed: 32130274
DOI: 10.1371/journal.pone.0229939 -
Molecules (Basel, Switzerland) May 2022Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in...
Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in plants. In this study, antiglaucoma, antidiabetic, anticholinergic, and antioxidant effects of Coumestrol were evaluated and compared with standards. To determine the antioxidant activity of coumestrol, several methods-namely N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD)-scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS)-scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH)-scavenging activity, potassium ferric cyanide reduction ability, and cupric ion (Cu)-reducing activity-were performed. Butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants for comparison. Coumestrol scavenged the DPPH radical with an IC value of 25.95 μg/mL (r: 0.9005) while BHA, BHT, Trolox, and α-Tocopherol demonstrated IC values of 10.10, 25.95, 7.059, and 11.31 μg/mL, respectively. When these results evaluated, Coumestrol had similar DPPH-scavenging effect to BHT and lower better than Trolox, BHA and α-tocopherol. In addition, the inhibition effects of Coumestrol were tested against the metabolic enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which are associated with some global diseases such as Alzheimer's disease (AD), glaucoma, and diabetes. Coumestrol exhibited K values of 10.25 ± 1.94, 5.99 ± 1.79, 25.41 ± 1.10, and 30.56 ± 3.36 nM towards these enzymes, respectively.
Topics: Acetylcholinesterase; Antioxidants; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Butyrylcholinesterase; Carbonic Anhydrases; Coumestrol; Free Radical Scavengers; Glycoside Hydrolases; alpha-Tocopherol
PubMed: 35630566
DOI: 10.3390/molecules27103091