Photophysical Characterization of a Benzo-Fused Analogue of Brooker’s Merocyanine: Solvent Polarity and pH Effects

2012 ◽  
Vol 116 (51) ◽  
pp. 12470-12475 ◽  
Author(s):  
Edward Adjaye-Mensah ◽  
Walter G. Gonzalez ◽  
Jaroslava Miksovska ◽  
James N. Wilson
Keyword(s):  
Solvent Polarity ◽  
Ph Effects ◽  
Brooker’S Merocyanine

Characterization of mitochondria isolated from the freezing-tolerant larvae of the goldenrod gall fly (Eurosta solidaginis): substrate preferences, salt effects, and pH effects on warm- and cold-acclimated animals

1985 ◽  
Vol 63 (2) ◽  
pp. 373-379 ◽  
Author(s):  
James S. Ballantyne ◽  
Kenneth B. Storey
Keyword(s):  
Salt Concentration ◽  
Respiratory Control ◽  
Ph Effects ◽  
Respiratory Control Ratio ◽  
Eurosta Solidaginis ◽  
Optimal Range ◽  
Salt Effects ◽  
Substrate Preferences ◽  
Optimal Ph

The mitochondria of the freezing-tolerant larvae of the goldenrod gall fly (Eurosta solidaginis) have been isolated and characterized. Proline is the preferred substrate of mitochondria from both warm- and cold-acclimated animals based on state 3 rates. Lipid is used as a substrate by warm- and cold-acclimated mitochondria assayed at 20 °C, but not by the mitochondria from cold-acclimated animals assayed at 1 °C. Cold-acclimated mitochondria assayed at 1 °C have a higher and broader optimal range of salt concentration for the oxidation of proline based on the respiratory control ratio (RCR) than those from warm-acclimated animals oxidizing the same substrate at 20 °C. The optimal pH for warm-acclimated mitochondria oxidizing proline at 20 °C is low (6.2) based on the RCR, but rises to pH 7.0 in cold-acclimated animals at 1 °C. It is suggested that the broad optimal salt concentration in the cold-acclimated animals and the very low optimal pH in warm-acclimated animals are adaptations for survival in this freezing-tolerant larva.

Synthesis and Characterization of Novel Degradable Responsive Polyurethane Microsphere

2013 ◽  
Vol 750-752 ◽  
pp. 1271-1275 ◽  
Author(s):  
Lian Hai Shan ◽  
Yuan Yuan Cui ◽  
Shuai Huang ◽  
Zhi Bin Zhang
Keyword(s):  
Drug Delivery ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Solvent Polarity ◽  
Toluene Diisocyanate ◽  
Synthesis And Characterization ◽  
The Novel ◽  
Swelling Ratio ◽  
Swelling Properties

The present study describes degradable polyurethane (PU) microspheres fabricated using toluene diisocyanate, polycaprolactone, polyethylene glycol, 2, 2-hydroxymethyl-2-propionic acid and triethylamine for drug delivery. The novel microspheres were synthesized using self-emulsion and condensed phase separation method. Fourier-Transform Infrared Spectrum analysis (FTIR) was performed revealing the chemical structure of polyurethane microspheres with special chains changing. Swelling properties influenced by solvent polarity, PEG content, PEG molecular weight, were evaluated, suggesting that the swelling ratio (SR) of PU microspheres increased with the increase in solvent polarity, PEG content and PEG molecular weight respectively.

scholarly journals Environment-Sensitive Fluorescent Labelling of Peptides by Luciferin Analogues

2021 ◽  
Vol 22 (24) ◽  
pp. 13312
Author(s):  
Marialuisa Siepi ◽  
Rosario Oliva ◽  
Antonio Masino ◽  
Rosa Gaglione ◽  
Angela Arciello ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Emission Spectra ◽  
Water Concentration ◽  
Solvent Polarity ◽  
Firefly Luciferase ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Water Abundance ◽  
Proteins And Peptides

Environment-sensitive fluorophores are very valuable tools in the study of molecular and cellular processes. When used to label proteins and peptides, they allow for the monitoring of even small variations in the local microenvironment, thus acting as reporters of conformational variations and binding events. Luciferin and aminoluciferin, well known substrates of firefly luciferase, are environment-sensitive fluorophores with unusual and still-unexploited properties. Both fluorophores show strong solvatochromism. Moreover, luciferin fluorescence is influenced by pH and water abundance. These features allow to detect local variations of pH, solvent polarity and local water concentration, even when they occur simultaneously, by analyzing excitation and emission spectra. Here, we describe the characterization of (amino)luciferin-labeled derivatives of four bioactive peptides: the antimicrobial peptides GKY20 and ApoBL, the antitumor peptide p53pAnt and the integrin-binding peptide RGD. The two probes allowed for the study of the interaction of the peptides with model membranes, SDS micelles, lipopolysaccharide micelles and Escherichia coli cells. Kd values and binding stoichiometries for lipopolysaccharide were also determined. Aminoluciferin also proved to be very well-suited to confocal laser scanning microscopy. Overall, the characterization of the labeled peptides demonstrates that luciferin and aminoluciferin are previously neglected environment-sensitive labels with widespread potential applications in the study of proteins and peptides.

scholarly journals Partial Characterization of Extracellular α-Amylase from Three Bacillus Isolates

1970 ◽  
Vol 25 (1) ◽  
pp. 76-78 ◽  
Author(s):  
Arifa Nusrat ◽  
Sabita Rezwana Rahman
Keyword(s):  
Metal Ions ◽  
Enzyme Activities ◽  
Soluble Starch ◽  
Positive Influence ◽  
Ph Effects ◽  
Ammonium Sulphate Precipitation ◽  
Wide Range ◽  
Bacillus Spp ◽  
Optimum Reaction

α-Amylase produced by three Bacillus isolates had been compared on the basis of the following criteria: heat and pH effects on activity and stability, effect of metal ions on enzyme activity and kinetic parameters. The culture filtrates obtained by growing the organisms in starch medium were fractionated by ammonium sulphate precipitation technique, and the highest enzyme activities were recovered from 70% saturation fraction. The enzyme from Bacillus amyloliquefaciens showed optimum activity at 60°C, while B. subtilis and another Bacillus isolate at lower (55°C) temperature. The pH optima of the enzymes from all sources were between 6.5 and 7.0 with an optimum reaction time of 10 to 15 min. α-Amylases were moderately thermostable exhibiting almost full activities at 50°C for at least 20 min. The enzyme from all sources showed stability over a wide range of pH (4.0-8.5). The apparent Km values on soluble starch varied between 1.6 mg/ml in case of B. amyloliquefaciens and 2.5 mg/ml in case of B. subtilis. Metal ions like Mg2+ and Mn2+ seemed to have positive influence on the enzyme activities of B. subtilis and Bacillus sp. The enzyme activities from three isolates were strongly inhibited by Cu2+, Hg2+ and Zn2+. Key words: Extracellular α-amylase; Bacillus spp.; Enzyme characterizationDOI: http://dx.doi.org/10.3329/bjm.v25i1.4864 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 76-78

Evaluation of the aluminium-induced root growth inhibition in isolation from low pH effects in Glycine max, Pisum sativum and Phaseolus vulgaris

1999 ◽  
Vol 26 (2) ◽  
pp. 147 ◽  
Author(s):  
Dennis B. Lazof ◽  
Michael J. Holland
Keyword(s):  
Glycine Max ◽  
Phaseolus Vulgaris ◽  
Pisum Sativum ◽  
Recovery Period ◽  
Solution Culture ◽  
Interactive Effects ◽  
Root Growth Inhibition ◽  
Ph Effects ◽  
Glycine Max L

The interaction between proton and aluminium toxicities was examined in soybean (Glycine max L.), pea (Pisum sativum L.) and bean (Phaseolus vulgaris L.). Accurate characterization of genotype Al-sensitivity in solution culture experiments, employing a continuous Al-exposure, required response definition at both growth-enhancing and growth inhibiting activities. Essentially, this involved multiple controls to account for the interactive effects. Experiments measuring growth during a recovery period in Al-free solution were more successful in distinguishing genotypic response to Al, especially in species demonstrating high H+ -sensitivity. The time, concentration and basal solution dependencies of the characteristic genotype response for the three species examined were consistent with the hypothesis that responses of genotypes may be predicated upon conditions emphasizing irreversible (cell division) effects. Cell extension effects, however, appear to be rapid, largely-reversible and often not different between differentially Al-sensitive genotypes growing in a complete nutrient solution.

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