Determination of apoplastic Na+ in intact leaves of cotton by in vivo fluorescence ratio-imaging

2002 ◽  
Vol 29 (12) ◽  
pp. 1491 ◽  
Author(s):  
Karl H. Mühling ◽  
André Läuchli
Keyword(s):  
Mature Leaves ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Compatible Osmolytes ◽  
Concentration Changes ◽  
Sodium Binding ◽  
Leaf Apoplast

Salinity may reduce plant growth via Na+-toxicity symptoms in mature leaves after long-term exposure. It has been suggested by other authors that Na+ accumulates in the leaf apoplast and leads to dehydration of leaves, wilting, and finally to death of these leaves. Two methods were employed to determine the Na+ concentration in the leaf apoplast of salt-tolerant cotton plants under salinity. The ratio imaging of sodium-binding benzofuran isophthalate (SBFI) fluorescence was used to detect in vivo concentration changes and gradients of Na+ within the leaf apoplast under salinity stress, and results were compared with the infiltration–centrifugation method. A�significant increase in Na+ concentration was found in the leaf apoplast under salinity (75 mM NaCl), but no further significant increase was determined when NaCl supply was increased from 75 to 150 mM. Both methods revealed that Na+ concentrations remained relatively low, and thus could not be responsible for the decline in yield under salinity. The ratio images showed changes in Na+ concentration and gradients within the leaf apoplast under salt stress, and demonstrated the validity of the method. However, SBFI fluorescence was also influenced by pH, proteins and salt-induced compatible osmolytes.

Measurement of intracellular pH in fungal hyphae using BCECF and digital imaging microscopy: Evidence for a primary proton pump in the plasmalemma of a marine fungus

1990 ◽  
Vol 96 (4) ◽  
pp. 731-736
Author(s):  
JULIA M. DAVIES ◽  
C. BROWNLEE ◽  
D. H. JENNINGS
Keyword(s):  
Intracellular Ph ◽  
Proton Pump ◽  
Marine Organism ◽  
Marine Fungus ◽  
Primary Proton ◽  
Acetoxymethyl Ester ◽  
Fluorescence Ratio Imaging ◽  
Negative Membrane Potential ◽  
Ratio Imaging

The facultative marine fungus, Dendryphiella salina, has the most negative membrane potential yet recorded for a marine organism. The ionic basis for this is thought to be through the action of a primary proton pump, though there exists the possibility of electrogenic pumping of Na+ or Cl−, given the high ambient concentration of these ions. Fluorescence ratio imaging microscopy with the pH-sensitive fluorescent probe 2′,7′-bis-(2-carboxyethyl)-5(and-6) carboxyfluorescein (BCECF) has been used to estimate intracellular pH. Hyphae loaded readily with BCECF after incubation with the acetoxymethyl ester (BCECF/AM). Mean resting intracellular pH (pH1) was 7.3, calculated by comparing 490/450 nm fluorescence ratios with in vivo calibration curves obtained by pH equilibration using nigericin. Distinct pH compartments could be observed, corresponding to cytoplasmic and smaller vacuolar compartments. Sodium azide reversibly reduced pH1 by an average of 0.51 of a pH unit, though the response varied between individual hyphae. Inhibiting the plasmalemma ATPase with orthovanadate also reversibly decreased pH|. The results support the presence of a proton pump in the plasmamembrane. The energetic and evolutionary implications are discussed.

Evaluation of BCECF fluorescence ratio imaging to properly measure gastric intramucosal pH variations in vivo

2007 ◽  
Vol 12 (6) ◽  
pp. 064014 ◽  
Author(s):  
Philippe Rochon ◽  
Mercé Jourdain ◽  
Jacques Mangalaboyi ◽  
François Fourrier ◽  
Sylvie Soulié-Bégu ◽  
...  
Keyword(s):  
Fluorescence Ratio ◽  
Intramucosal Ph ◽  
Gastric Intramucosal Ph ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Ph Variations

scholarly journals In Vivo Assessment of Thromboresistant Materials by Determination of Platelet Survival

1977 ◽  
Author(s):  
N. Coe ◽  
R. Collins ◽  
A. Jagoda ◽  
D. Brier ◽  
J. Lindon ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Needle Puncture ◽  
Polydimethyl Siloxane ◽  
Artificial Surface ◽  
Long Term Behavior ◽  
Shunt Control ◽  
Free Plasma

The reactivity of potentially thromboresistant polymers was determined in sheep by measurement of the lifespan of Cr51-labelled platelets. Materials were tested as tubing (90-125 cm × 2.5-3 mm I.D.) interposed in a 7 cm silicone rubber carotid A.-ext. jugular V. shunt.Platelet lifespan decreased as the length of the basic silicone rubber shunt increased from 7 cm (“shunt control”, T½ 78.3 ± 11.6 S.D. hrs.; n = 18) to 50 cm (T½ 62.0 ± 7.5 hrs.; n=7; p< 0.001 vs. shunt control) but was longer than in sheep without a shunt (T½ 63.1 ± 11.2 hrs.; n=21; p<0.001 vs. shunt control), probably because of artifactual activation of platelets in blood sampling by needle puncture in the absence of a shunt. Of sixteen polymers studied in 42 sheep (n=117), all significantly shortened platelet lifespan except polyurethane (T½ 72.8 ± 12.1 hrs.; n=12) and non-cross-linked silica-free polydimethyl siloxane (T½ 69.8 ± 13.9 hrs.; n = 9). Polymethyl acrylate (PMA) (T½ 71.2 ± 5.4 hrs.; n=ll; p<0.04 vs. shunt control) was passivated by exposure to platelet free plasma before whole blood (T½ 90.3 ± 3.6 hrs.; n=5; ρ <0.05 vs. untreated PMA). Thus, the adsorbed film of plasma constituents has a lasting and decisive effect on thromboresistance of the surface. The long term behavior of an artificial surface may be dictated by the events of the first few seconds of blood-surface contact.

Perfusion of canine liver in vivo

1960 ◽  
Vol 15 (4) ◽  
pp. 687-690 ◽  
Author(s):  
William C. Shoemaker ◽  
Frederick G. Panico ◽  
William F. Walker ◽  
David H. Elwyn
Keyword(s):  
Whole Blood ◽  
Normal Pressure ◽  
Systemic Circulation ◽  
Term Survival ◽  
Concentration Changes ◽  
Neural Influences ◽  
Systemic Condition

A method is described for perfusing the canine liver in vivo and in situ with heparinized whole blood, together with preliminary data on concentration changes of several selected constituents of the perfusing blood or plasma. The porta hepatis is denervated in order to minimize neural influences on the hepatic vascular resistance. Prior to perfusion catheters are placed in the vessels without obstructing the blood flow and ligatures or nooses are loosely placed around the catheterized vessels. During this time the blood pressure and systemic condition of the animal is carefully maintained with transfusions and other fluids. When the ligatures are simultaneously drawn up and tied, the catheters become, in effect, cannulas, and the hepatic circulation is instantaneously and completely divorced from the remaining systemic circulation; at no time is there interruption of normal pressure and flow of oxygenated blood to the liver. Thus, hepatic swelling or congestion, which is thought to limit the perfusion, is minimized by denervation, minimal manipulation of the liver itself, maintenance of the animal's condition prior to the onset of perfusion, instantaneous changeover to the perfusing system and the use of heparinized, whole blood. After completion of the perfusion the normal vascular relationships may be re-established and, on occasion, long-term survival may be expected. Submitted on October 1, 1959

Persistence of a defective tuberoinfundibular dopaminergic function in rats after long-term removal of oestrogen treatment. An in vivo study

1985 ◽  
Vol 109 (3) ◽  
pp. 309-314 ◽  
Author(s):  
D. Cocchi ◽  
A. Peñalva ◽  
R. Torpia ◽  
G. L. Rossi ◽  
E. E. Müller
Keyword(s):  
Neuronal Function ◽  
Oestrogen Treatment ◽  
Clear Cut ◽  
Long Time ◽  
Previously Treated ◽  
Neuroactive Drugs ◽  
Plasma Prl

Abstract. The function of the tuberoinfundibular dopaminergic (TIDA) neurons of 49 rats bearing oestradiolvalerate (EV)-induced prolactin (Prl) secreting tumours (prolactinomas) was evaluated in vivo, 7 months after discontinuation of EV-treatment, with neuroactive drugs acting via stimulation or inhibition of DA neurotransmission. Based on the size and morphologic appearance of the pituitary and on determination of plasma Prl levels, rats previously treated with EV could be divided into those bearing macro- (31/49) and those bearing microprolactinomas (18/49). Administration of the indirect DA agonist drug nomifensine (10 mg/kg iv) lowered plasma Prl levels in control rats, but failed to do so in rats bearing either macro- or microprolactinomas. Administration of the DA receptor antagonist domperidone (50 μg/kg ip) or the synthetic enkephalin analogue FK 33-824 (1 mg/kg ip) failed to induce a rise in plasma Prl in rats with macro-, but induced a clear-cut rise in plasma Prl in those with microprolactinomas. Prl unresponsiveness to all three neuroactive drugs indicates that long time after EV withdrawal TIDA neuronal function is still highly impaired in rats bearing EVinduced macroprolactinomas. The impairment of TIDA neuronal function would be of lesser extent in rats bearing microprolactinomas as revealed by a defective response to only one of the three applied neuroendocrine probes.

scholarly journals Fluorescence Ratio Imaging Microscopy Shows Decreased Access of Vancomycin to Cell Wall Synthetic Sites in Vancomycin-Resistant Staphylococcus aureus

2007 ◽  
Vol 51 (10) ◽  
pp. 3627-3633 ◽  
Author(s):  
Pedro M. Pereira ◽  
Sérgio R. Filipe ◽  
Alexander Tomasz ◽  
Mariana G. Pinho
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Binding Capacity ◽  
Live Cells ◽  
Resistant Bacteria ◽  
Fluorescence Ratio ◽  
Lipid Ii ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging

ABSTRACT A new method of fluorescence ratio imaging microscopy was used to compare the in vivo binding capacity and the access of a fluorescent derivative of vancomycin to the cell wall synthetic sites in isogenic pairs of vancomycin-susceptible and -resistant laboratory mutants and vancomycin-intermediate and -susceptible clinical isolates of Staphylococcus aureus. Live cells of resistant strains were found to bind approximately 1.5 times more antibiotic, but there was no correlation between the increased binding capacity and the MICs of the strains. In both susceptible and resistant bacteria, the subcellular sites of wall synthesis were localized to the division septa, but the rate of diffusion of drug molecules to these sites was reduced in resistant cells. The findings allow a reinterpretation of the mechanism of vancomycin resistance in which the path of vancomycin to its lethal target (lipid II) is considered to be through the division septum and therefore is dependent on the stage of the staphylococcal cell cycle.

scholarly journals Noninvasive Measurement of Bacterial Intracellular pH on a Single-Cell Level with Green Fluorescent Protein and Fluorescence Ratio Imaging Microscopy

2002 ◽  
Vol 68 (8) ◽  
pp. 4145-4147 ◽  
Author(s):  
Katja N. Olsen ◽  
Birgitte B. Budde ◽  
Henrik Siegumfeldt ◽  
K. Björn Rechinger ◽  
Mogens Jakobsen ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Intracellular Ph ◽  
Fluorescent Protein ◽  
Direct Analysis ◽  
Bacterial Cells ◽  
Complex Environments ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Green Fluorescent

ABSTRACT We show that a pH-sensitive derivative of the green fluorescent protein, designated ratiometric GFP, can be used to measure intracellular pH (pHi) in both gram-positive and gram-negative bacterial cells. In cells expressing ratiometric GFP, the excitation ratio (fluorescence intensity at 410 and 430 nm) is correlated to the pHi, allowing fast and noninvasive determination of pHi that is ideally suited for direct analysis of individual bacterial cells present in complex environments.

scholarly journals Arsenene-mediated multiple independently targeted reactive oxygen species burst for cancer therapy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Na Kong ◽  
Hanjie Zhang ◽  
Chan Feng ◽  
Chuang Liu ◽  
Yufen Xiao ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cancer Therapy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Non Invasive ◽  
Ros Burst ◽  
Imaging Properties

AbstractThe modulation of intracellular reactive oxygen species (ROS) levels is crucial for cellular homeostasis and determination of cellular fate. A sublethal level of ROS sustains cell proliferation, differentiation and promotes tumor metastasis, while a drastic ROS burst directly induces apoptosis. Herein, surface-oxidized arsenene nanosheets (As/AsxOy NSs) with type II heterojunction are fabricated with efficient ·O2− and 1O2 production and glutathione consumption through prolonging the lifetime of photo-excited electron-hole pairs. Moreover, the portion of AsxOy with oxygen vacancies not only catalyzes a Fenton-like reaction, generating ·OH and O2 from H2O2, but also inactivates main anti-oxidants to cut off the “retreat routes” of ROS. After polydopamine (PDA) and cancer cell membrane (M) coating, the engineered As/AsxOy@PDA@M NSs serve as an intelligent theranostic platform with active tumor targeting and long-term blood circulation. Given its narrow-band-gap-enabled in vivo fluorescence imaging properties, As/AsxOy@PDA@M NSs could be applied as an imaging-guided non-invasive and real-time nanomedicine for cancer therapy.

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