Cell-associated cations of the moderate halophile Micrococcus varians ssp. halophilus grown in media of high concentrations of LiCl, NaCl, KCl, RbCl, or CsCl

1982 ◽  
Vol 28 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Masahiro Kamekura ◽  
Hiroshi Onishi
Keyword(s):  
Exponential Phase ◽  
Monovalent Cations ◽  
Complex Media ◽  
Moderate Halophile ◽  
Cation Concentration ◽  
Equivalent Concentration ◽  
High Concentrations

Micrococcus varians ssp. halophilus ATCC 21971 showed abundant growth in complex media containing 1 M NaCl, NaBr, NaI, NaNO3, Na2SO4, KCl, KBr, KI, or KNO3, and 2 M RbCl or RbBr at 30 °C.Spontaneous mutants were isolated which were able to grow in a medium of 1.5 M LiCl (strain Li-5) or 2.5 M CsCl (strain Cs-7-Cs). Determination of cell-associated cation concentration at the exponential phase of growth showed that the cells contained monovalent cations of almost equivalent concentration as that in the medium: 0.570 m Li+ + 0.951 m Na+ in 1.5 M LiCl grown cells; 2.88 m Na+ in 3.0 M NaCl grown cells; 2.66 m K+ in 3.0 M KCl grown cells; 1.57 m Rb+ in 2.0 M RbCl grown cells; 1.44 m Cs+ in 1.5 M CsCl grown cells.

Evidence of a novel role for monovalent cations in pyruvate kinase catalysis

1976 ◽  
Vol 54 (5) ◽  
pp. 393-397 ◽  
Author(s):  
James L. Robinson
Keyword(s):  
Pyruvate Kinase ◽  
Divalent Cation ◽  
Monovalent Cation ◽  
Monovalent Cations ◽  
Forward Reaction ◽  
Cation Concentration ◽  
High Concentrations ◽  
Reaction Inhibition

In the pyruvate kinase (EC 2.7. 1.40) reaction, the complete enzyme–products complex consists of enzyme, pyruvate, ATP, a divalent cation, and a monovalent cation, usually K+. The dissociation of this, complex can be slow permitting reversible enolization of pyruvate in this complex during the course of the forward reaction. High concentrations of each component in the enzyme–products complex inhibits the forward reaction, but only elevated concentrations of the monovalent cation decrease the net rate of product dissociation relative to that of pyruvate enolization. This result indicates that the monovalent cation can be the first component released from the enzyme–products complex and that the presence of an inhibiting monovalent cation concentration leads to re-formation of the complete complex, which is necessary for pyruvate enolization. The evidence suggests that the monovalent cation can bind and release with each turnover of the enzyme. While the data do not permit the conclusion that first release of monovalent cation is the exclusive pathway for dissociation of the enzyme–products complex, no other component once released can reassociate rapidly enough to form a complete complex during the forward reaction. Inhibition by these components must be attributed to the formation of abortive complexes.

Methods for the Determination of the Purity of Exosomes

2020 ◽  
Vol 25 (42) ◽  
pp. 4464-4485 ◽  
Author(s):  
Katarzyna Kluszczyńska ◽  
Liliana Czernek ◽  
Wojciech Cypryk ◽  
Łukasz Pęczek ◽  
Markus Düchler
Keyword(s):  
Drug Transport ◽  
Biological Fluids ◽  
Drug Carriers ◽  
Biological Functions ◽  
Isolation And Purification ◽  
Pubmed Database ◽  
High Concentrations ◽  
Targeted Release

Background: Exosomes open exciting new opportunities for advanced drug transport and targeted release. Furthermore, exosomes may be used for vaccination, immunosuppression or wound healing. To fully utilize their potential as drug carriers or immune-modulatory agents, the optimal purity of exosome preparations is of crucial importance. Methods: Articles describing the isolation and purification of exosomes were retrieved from the PubMed database. Results: Exosomes are often separated from biological fluids containing high concentrations of proteins, lipids and other molecules that keep vesicle purification challenging. A great number of purification protocols have been published, however, their outcome is difficult to compare because the assessment of purity has not been standardized. In this review, we first give an overview of the generation and composition of exosomes, as well as their multifaceted biological functions that stimulated various medical applications. Finally, we describe various methods that have been used to purify small vesicles and to assess the purity of exosome preparations and critically compare the quality of these evaluation protocols. Conclusion: Combinations of various techniques have to be applied to reach the required purity and quality control of exosome preparations.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Electroanalytical Techniques for the Detection of Selenium as a Biologically and Environmentally Significant Analyte—A Short Review

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1768
Author(s):  
Miroslav Rievaj ◽  
Eva Culková ◽  
Damiána Šandorová ◽  
Zuzana Lukáčová-Chomisteková ◽  
Renata Bellová ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Essential Element ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Stripping Voltammetry ◽  
Short Review ◽  
Electroanalytical Methods ◽  
High Concentrations ◽  
Speed Of Analysis

This short review deals with the properties and significance of the determination of selenium, which is in trace amounts an essential element for animals and humans, but toxic at high concentrations. It may cause oxidative stress in cells, which leads to the chronic disease called selenosis. Several analytical techniques have been developed for its detection, but electroanalytical methods are advantageous due to simple sample preparation, speed of analysis and high sensitivity of measurements, especially in the case of stripping voltammetry very low detection limits even in picomoles per liter can be reached. A variety of working electrodes based on mercury, carbon, silver, platinum and gold materials were applied to the analysis of selenium in various samples. Only selenium in oxidation state + IV is electroactive therefore the most of voltammetric determinations are devoted to it. However, it is possible to detect also other forms of selenium by indirect electrochemistry approach.

scholarly journals The Double Face of Ketamine—The Possibility of Its Identification in Blood and Beverages

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 813
Author(s):  
Magdalena Świądro ◽  
Paweł Stelmaszczyk ◽  
Irena Lenart ◽  
Renata Wietecha-Posłuszny
Keyword(s):  
Date Rape ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Heroin Addiction ◽  
Assisted Extraction ◽  
Low Concentrations ◽  
High Concentrations ◽  
Rosé Wine ◽  
Tof Ms

The purpose of this study was to develop and validate a high-sensitivity methodology for identifying one of the most used drugs—ketamine. Ketamine is used medicinally to treat depression, alcoholism, and heroin addiction. Moreover, ketamine is the main ingredient used in so-called “date-rape” pills (DRP). This study presents a novel methodology for the simultaneous determination of ketamine based on the Dried Blood Spot (DBS) method, in combination with capillary electrophoresis coupled with a mass spectrometer (CE-TOF-MS). Then, 6-mm circles were punched out from DBS collected on Whatman DMPK-C paper and extracted using microwave-assisted extraction (MAE). The assay was linear in the range of 25–300 ng/mL. Values of limits of detection (LOD = 6.0 ng/mL) and quantification (LOQ = 19.8 ng/mL) were determined based on the signal to noise ratio. Intra-day precision at each determined concentration level was in the range of 6.1–11.1%, and inter-day between 7.9–13.1%. The obtained precision was under 15.0% (for medium and high concentrations) and lower than 20.0% (for low concentrations), which are in accordance with acceptance criteria. Therefore, the DBS/MAE/CE-TOF-MS method was successfully checked for analysis of ketamine in matrices other than blood, i.e., rose wine and orange juice. Moreover, it is possible to identify ketamine in the presence of flunitrazepam, which is the other most popular ingredient used in DRP. Based on this information, the selectivity of the proposed methodology for identifying ketamine in the presence of other components of rape pills was checked.

scholarly journals Effects of Macronutrients in the Physiological Quality of Soybean Seeds

2018 ◽  
Vol 10 (5) ◽  
pp. 312
Author(s):  
Geliandro Anhaia Rigo ◽  
Luis Osmar Braga Schuch ◽  
Willian Silva Barros ◽  
Rodrigo Lamaison de Vargas ◽  
Vinícius Jardel Szareski ◽  
...  
Keyword(s):  
Graduate Program ◽  
Plant Tissues ◽  
Soybean Seeds ◽  
Rio Grande Do Sul ◽  
Genetic Characteristics ◽  
Physiological Quality ◽  
High Concentrations ◽  
Nitrogen Phosphorus

The aim of this work was to correlate macronutrient content of soybean seeds to physiological quality of different cultivars. The work was developed in the Federal University of Pelotas, in the facilities of the Seed Science and Technology Graduate Program. The experimental design was randomized blocks in arranged in four replicates. The following soybean cultivars were used: BMX Apolo RR (12 lots), BMX Ativa RR (13 lots), BMX Energia RR (26 lots), BMX Força RR (24 lots), BMX Impacto RR (35 lots), BMX Magna RR (16 lots), BMX Turbo RR (44 lots), BMX Potência RR (82 lots) and NA 5909 RR (28 lots), with seeds produced in northwest Rio Grande do Sul. The determination of nutritional contents found in plant tissues of soybean seeds, were measured: Nitrogen (N), Phosphorus (P), Potassium (K), Magnesium (Mg), Calcium (Ca), Sulfur (S). The macronutrient contents of the seeds vary according to genetic characteristics of the cultivars, with higher oscillations of nitrogen, phosphorus, magnesium and sulfur contents present in soybean seeds. Potassium and calcium are defined as the most stable nutrients for the cultivars and seed lots analyzed. High concentrations of nitrogen, phosphorus and calcium are determinants for the physiological quality of soybean seeds.

scholarly journals Evaluation of the kinetics of oxidation and removal of organic matter in the self-purification of a mountain river

DYNA ◽  
2015 ◽  
Vol 82 (191) ◽  
pp. 183-193 ◽  
Author(s):  
Jorge Virgilio Rivera Gutiérrez
Keyword(s):  
Water Quality ◽  
Water System ◽  
The Self ◽  
Organic Load ◽  
Mountain River ◽  
Kinetics Of Oxidation ◽  
Kinetic Rates ◽  
High Concentrations ◽  
Kinetics Of

The study is based on the determination of the kinetic rates and assessment of self-purification of the Frio River, due to the uptake of organic load. The kinetic rates were calculated by applying differential and logarithmic methods on concentrations of water quality determinants present in each of the (7) reach of the river. The water system easily recovers the amount of oxygen, k<sub>d</sub>= 0.4, k<sub>a</sub> 3.2 d<sup>-1</sup>, only receives 27.7 Ton. d<sup>-1</sup>, the organic load, making high concentrations of carbon, ammonium and remain sediment. The length Influence of discharges, LIV- BOD yielded a mean per tranche of 10 km, compared to 3 km each way, means that the river can´t self- purification that need more length of travel. The study illustrates the modeling of the determinants of quality, developed by the QUAL2K, using the calculated rates.

scholarly journals Application of Advanced Drying Technologies for Obtaining Bioactive Beer Yeast and Grape Seed Extract Powders

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Alina NICULA ◽  
Alexandru. T. NICULA ◽  
Carmen SOCACIU ◽  
Pierre DuBREUCQ
Keyword(s):  
Bioactive Compound ◽  
Grape Seed Extract ◽  
Grape Seed ◽  
Seed Extract ◽  
Outlet Temperature ◽  
Drying Process ◽  
Fluid Bed ◽  
High Concentrations ◽  
Beer Yeast

As the food industry is interested to recuperate the valuable waste such as beer yeast (Saccharomyces cervisiae) and grape seed (Vitis vinifera), both with high nutritional and health promotion effects, new products and processes are expected to be released on the market. The new modern drying technologies used to process natural compounds and extracts aim a protected evaporation under controlled temperatures and immobilization on matrices, in order to keep high concentrations of bioactive compound in the final products. One of the most important technological parameter during the drying process is the Inlet and Outlet Temperature Using Spray Drying (SD) and Fluid Bed Drying (FBD) optimized technologies we obtained beer yeast (BY) and the grape seed extract (GSE) solid forms, demonstrating that functionality is well preserved (by determination of vitamins B and phenolics, respectively) in the final products comparing with the initial, genuine extracts. Beer yeast and grape seed concentrated forms (stabilized powders and granulated formulas) have emerging consequences in this context and attract the modern consumer for their positive action on health.

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