ChemInform Abstract: FUNCTIONAL CAPSULE MEMBRANES. 10. PH-SENSITIVE CAPSULE MEMBRANES. REVERSIBLE LE PERMEABILITY CONTROL FROM THE DISSOCIATIVE BILAYER-COATED CAPSULE MEMBRANE BY AN AMBIENT PH CHANGE

1985 ◽  
Vol 16 (17) ◽  
Author(s):  
Y. OKAHATA ◽  
T. SEKI
Keyword(s):  
Ph Sensitive ◽  
Ph Change

Correction: Evaluation of Root pH Change Through Gel Containing pH-sensitive Indicator Bromocresol Purple

BIO-PROTOCOL ◽  
2018 ◽  
Vol 8 (8) ◽  
Author(s):  
Aparecida Silva ◽  
Keini Dressano ◽  
Paulo Ceciliato ◽  
Juan Carlos Guerrero-Abad ◽  
Daniel Moura
Keyword(s):  
Ph Sensitive ◽  
Sensitive Indicator ◽  
Bromocresol Purple ◽  
Ph Change

scholarly journals Evaluation of Root pH Change Through Gel Containing pH-sensitive Indicator Bromocresol Purple

BIO-PROTOCOL ◽  
2018 ◽  
Vol 8 (7) ◽  
Author(s):  
Aparecida Silva ◽  
Keini Dressano ◽  
Paulo Ceciliato ◽  
Juan Carlos Guerrero-Abad ◽  
Daniel Moura
Keyword(s):  
Ph Sensitive ◽  
Sensitive Indicator ◽  
Bromocresol Purple ◽  
Ph Change

scholarly journals Dynamic Nucleolar Targeting of Dengue Virus Polymerase NS5 in Response to Extracellular pH

2016 ◽  
Vol 90 (12) ◽  
pp. 5797-5807 ◽  
Author(s):  
Johanna E. Fraser ◽  
Stephen M. Rawlinson ◽  
Steven M. Heaton ◽  
David A. Jans
Keyword(s):  
Dengue Virus ◽  
Environmental Changes ◽  
Fluorescent Protein ◽  
Nonstructural Protein ◽  
Ph Sensitive ◽  
Extracellular Ph ◽  
Ph Change ◽  
Transfected Cells ◽  
Infected Cells ◽  
First Time

ABSTRACTThe nucleolar subcompartment of the nucleus is increasingly recognized as an important target of RNA viruses. Here we document for the first time the ability of dengue virus (DENV) polymerase, nonstructural protein 5 (NS5), to accumulate within the nucleolus of infected cells and to target green fluorescent protein (GFP) to the nucleolus of live transfected cells. Intriguingly, NS5 exchange between the nucleus and nucleolus is dynamically modulated by extracellular pH, responding rapidly and reversibly to pH change, in contrast to GFP alone or other nucleolar and non-nucleolar targeted protein controls. The minimal pH-sensitive nucleolar targeting region (pHNTR), sufficient to target GFP to the nucleolus in a pH-sensitive fashion, was mapped to NS5 residues 1 to 244, with mutation of key hydrophobic residues, Leu-165, Leu-167, and Val-168, abolishing pHNTR function in NS5-transfected cells, and severely attenuating DENV growth in infected cells. This is the first report of a viral protein whose nucleolar targeting ability is rapidly modulated by extracellular stimuli, suggesting that DENV has the ability to detect and respond dynamically to the extracellular environment.IMPORTANCEInfections by dengue virus (DENV) threaten 40% of the world's population yet there is no approved vaccine or antiviral therapeutic to treat infections. Understanding the molecular details that govern effective viral replication is key for the development of novel antiviral strategies. Here, we describe for the first time dynamic trafficking of DENV nonstructural protein 5 (NS5) to the subnuclear compartment, the nucleolus. We demonstrate that NS5's targeting to the nucleolus occurs in response to acidic pH, identify the key amino acid residues within NS5 that are responsible, and demonstrate that their mutation severely impairs production of infectious DENV. Overall, this study identifies a unique subcellular trafficking event and suggests that DENV is able to detect and respond dynamically to environmental changes.

scholarly journals Fabrication of pH-Sensitive Tetramycin Releasing Gel and Its Antibacterial Bioactivity against Ralstonia solanacearum

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3606
Author(s):  
Xiaozhou Ma ◽  
Shunyu Xiang ◽  
Huijun Xie ◽  
Linhai He ◽  
Xianchao Sun ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Onset Time ◽  
Ph Sensitive ◽  
Ph Change ◽  
Great Loss ◽  
Management Efficiency ◽  
High Incidence ◽  
Application Potential ◽  
Base Structure

Ralstonia solanacearum (R. solanacearum)-induced bacterial wilt of the nightshade family causes a great loss in agricultural production annually. Although there has been some efficient pesticides against R. solanacearum, inaccurate pesticide releasing according to the onset time of bacterial wilt during the use of pesticides still hinders the disease management efficiency. Herein, on the basis of the soil pH change during R. solanacearum growth, and pH sensitivity of the Schiff base structure, a pH-sensitive oxidized alginate-based double-crosslinked gel was fabricated as a pesticide carrier. The gel was prepared by crosslinking oxidized sodium alginate (OSA) via adipic dihydrazide (ADH) and Ca2+. After loading tetramycin into the gel, it showed a pH-dependent pesticide releasing behavior and anti-bacterial activity against R. solanacearum. Further study also showed that the inhibition rate of the tetramycin-loaded gel was higher than that of industrial pesticide difenoconazole. This work aimed to reduce the difficulty of pesticide administration in the high incidence period of bacterial wilt and we believe it has a great application potential in nightshade production.

scholarly journals An Extended Gate Field Effect Transistor (EGFET)-based pH Microsensor Utilizing a Polypyyrole Coated pH Microelectrode

2021 ◽  
Author(s):  
Mustafa ŞEN ◽  
Fikri Seven
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Ph Sensitive ◽  
Oxide Semiconductor ◽  
Three Solutions ◽  
Ph Change ◽  
Ph Measurements ◽  
Corrosion Studies ◽  
Effect Transistor ◽  
Local Ph

Here, an ultra-small size, simple and inexpensive metal oxide semiconductor field effect transistor (MOSFET)-integrated needle type EGFET pH microsensor was fabricated. The EGFET pH mi?crosensor has the potential to be applied to fast and precise local pH measurements. The system was composed of two components; a pH sensitive probe and a MOSFET. The pH sensitive probe wasmade by electrochemically coating the surface of a Pt ultra micro-electrode with polypyrrole, a semi-conductor polymer. The pH sensitive probe was then integrated with the gate of the MOSFET to carry out measurements in PBS at different pH values. The real time response of the EGFET pH microsen?sor was also tested by cycling the probe in three solutions at different pH. The results showed that the developed pH microsensor is sensitive to pH change. It is expected that the EGFET pH microsensor will allow local pH analysis in biological samples or corrosion studies

The enzymatic activity of phosphoglycerate mutase from gram-positive endospore-forming bacteria requires Mn2+ and is pH sensitive

1998 ◽  
Vol 44 (8) ◽  
pp. 759-767 ◽  
Author(s):  
Monica Chander ◽  
Barbara Setlow ◽  
Peter Setlow
Keyword(s):  
Enzymatic Activity ◽  
Micrococcus Luteus ◽  
Streptomyces Coelicolor ◽  
Ph Sensitive ◽  
Phosphoglycerate Mutase ◽  
Glyceric Acid ◽  
Ph Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Phosphoglyceric Acid

The enzymatic activity of phosphoglycerate mutase (Pgm) from three gram-positive endospore-forming bacteria (Bacillus subtilis, Clostridium perfringens, and Sporosarcina ureae) requires Mn2+ and is very sensitive to pH; at low concentrations of Mn2+, a pH change from 8 to 6 resulted in greater than 30- to 200-fold decreases in the activity of these Pgms. However, Pgm deactivation at pH 6 was reversed by shifting the enzyme to pH 7 or 8. Free Mn2+ was not directly involved in Pgm catalysis, although enzyme-bound Mn2+ may be involved. The rate of catalysis by Mn2+-containing Pgm was also slightly pH dependent, although the Km for 3-phosphoglyceric acid appeared to be the same at pH 6, 7, and 8. These findings suggest that Mn2+ binds to catalytically inactive Pgm and converts it to a catalytically competent form, and further, that pH influences the efficiency with which the enzyme binds Mn2+. The extreme pH sensitivity of the Mn2+-dependent Pgms supports a model in which this enzyme is inhibited during sporulation by acidification of the forespore, thus allowing accumulation of the spore's large depot of 3-phospho-glyceric acid. The activity of Pgm from two closely related gram-positive bacteria that do not form spores (Planococcus citreus and Staphylococcus saprophyticus) also requires Mn2+ and is pH sensitive. In contrast, the Pgm activities from two more distantly related non-endospore-forming gram-positive bacteria (Micrococcus luteus and Streptomyces coelicolor) are neither dependent on metal ions nor particularly sensitive to pH.Key words: Bacillus, Clostridium, Mn2+, phosphoglycerate mutase, sporulation.

Absence of an intracellular pH change following fertilisation of the mouse egg

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 305-311 ◽  
Author(s):  
Douglas Kline ◽  
James A. Zagray
Keyword(s):  
Intracellular Ph ◽  
Photon Counting ◽  
Fluorescence Emission ◽  
Ph Sensitive ◽  
Egg Activation ◽  
Ph Change ◽  
Hoechst 33342 ◽  
Intracellular Ca ◽  
Mouse Egg ◽  
Expected Increase

SummaryThe intracellular pH of the mouse egg was measured during fertilisation to determine whether an increase in pH accompanies activation of this mammalian egg. The pH-sensitive dye BCECF [2′,7′-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein] was introduced into the mouse egg by incubation in BCECF-AM or by microinjection of dextran-conjugated BCECF. The cells were also loaded with the DNA-specific fluorochrome Hoechst 33342 to confirm fertilisation by observation of Hoechst-stained, decondensing sperm heads in the cytoplasm. The ratio of emission intensities for the dye (494/440 nm excitation wavelengths) was monitored continuously with a photon-counting photomultiplier tube. There was no change in pH during or after fertilisation. Control eggs displayed the expected increase in pH when exposed to NH4C1. In other experiments, intracellular pH and intracellular Ca2+ were monitored simultaneously during fertilisation. The eggs were injected with BCECF dextran and Fura dextran. Fluorescence emission was recorded at excitation wavelengths of 495 nm (BCECF, pH-sensitive wavelength) and 385 nm (Fura, Ca2+-sensitive wavelength). A decrease in emission intensity at 385 nm excitation clearly marked the repetitive Ca2+ transients at egg activation. There was no change in the fluorescence emitted at 495 nm excitation, indicating an absence of any change in intracellular pH. These results indicate that intracellular alkalinisation of the cytoplasm does not accompany activation of this vertebrate egg.

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