scholarly journals Multiparameter Flow Cytometric Analysis of Antibiotic Effects on Membrane Potential, Membrane Permeability, and Bacterial Counts of Staphylococcus aureus andMicrococcus luteus

2000 ◽  
Vol 44 (4) ◽  
pp. 827-834 ◽  
Author(s):  
David J. Novo ◽  
Nancy G. Perlmutter ◽  
Richard H. Hunt ◽  
Howard M. Shapiro
Keyword(s):  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Membrane Potential ◽  
Membrane Permeability ◽  
Micrococcus Luteus ◽  
Flow Cytometric Analysis ◽  
Bacterial Counts ◽  
Flow Cytometric ◽  
Permeability Parameter ◽  
Particle Counts

ABSTRACT Although flow cytometry has been used to study antibiotic effects on bacterial membrane potential (MP) and membrane permeability, flow cytometric results are not always well correlated to changes in bacterial counts. Using new, precise techniques, we simultaneously measured MP, membrane permeability, and particle counts of antibiotic-treated and untreated Staphylococcus aureus andMicrococcus luteus cells. MP was calculated from the ratio of red and green fluorescence of diethyloxacarbocyanine [DiOC2(3)]. A normalized permeability parameter was calculated from the ratio of far red fluorescence of the nucleic acid dye TO-PRO-3 and green DiOC2(3) fluorescence. Bacterial counts were calculated by the addition of polystyrene beads to the sample at a known concentration. Amoxicillin increased permeability within 45 min. At concentrations of <1 μg/ml, some organisms showed increased permeability but normal MP; this population disappeared after 4 h, while bacterial counts increased. At amoxicillin concentrations above 1 μg/ml, MP decreased irreversibly and the particle counts did not increase. Tetracycline and erythromycin caused smaller, dose- and time-dependent decreases in MP. Tetracycline concentrations of <1 μg/ml did not change permeability, while a tetracycline concentration of 4 μg/ml permeabilized 50% of the bacteria; 4 μg of erythromycin per ml permeabilized 20% of the bacteria. Streptomycin decreased MP substantially, with no effect on permeability; chloramphenicol did not change either permeability or MP. Erythromycin pretreatment of bacteria prevented streptomycin and amoxicillin effects. Flow cytometry provides a sensitive means of monitoring the dynamic cellular events that occur in bacteria exposed to antibacterial agents; however, it is probably simplistic to expect that changes in a single cellular parameter will suffice to determine the sensitivities of all species to all drugs.

scholarly journals Chromosome doubling in Cattleya tigrina A. Rich

2019 ◽  
Vol 15 (11) ◽  
Author(s):  
Thays Saynara Alves Menezes-Sá ◽  
Maria de Fátima Arrigoni-Blank ◽  
Andréa Santos da Costa ◽  
Janay De Almeida Santos-Serejo ◽  
Arie Fitzgerald Blank ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Propidium Iodide ◽  
Chromosome Doubling ◽  
Flow Cytometric Analysis ◽  
Leaf Tissue ◽  
Stomatal Index ◽  
Chromosome Duplication ◽  
Flow Cytometric ◽  
Young Leaves ◽  
Commercial Value

Chromosome doubling induction in orchids may benefit their production for resulting in flowers of higher commercial value, larger size and higher content of substances that intensify the color and fragrance when compared with diploid orchids. This work aimed to induce and confirm artificial polyploidization, using flow cytometry and stomatal analysis. Explants were treated with colchicine at concentrations of 0, 2.5, 7.5, and 12.5 mM, for 24 and 48 hours and with oryzalin, at concentrations of 0, 10, 30, and 50 μM, for three and six days. For the flow cytometric analysis, a sample of leaf tissue was removed from each plant, crushed to release the nuclei and stained with propidium iodide. In addition to flow cytometry, the ploidy of the antimitotic treated plants was evaluated by stomata analysis. Young leaves were used where the density, functionality and stomatal index were evaluated. Colchicine provided induction of satisfactory polyploidy in C. tigrina at all concentrations and times of exposure, obtaining a greater number of polyploid individuals in the concentration of 12.5 mM for 48 hours. Oryzalin did not induce chromosome duplication at the tested concentrations.

Characterization of Staphylococcus aureus-Platelet Binding by Quantitative Flow Cytometric Analysis

1992 ◽  
Vol 166 (1) ◽  
pp. 65-73 ◽  
Author(s):  
M. R. Yeaman ◽  
P. M. Sullam ◽  
P. F. Dazin ◽  
D. C. Norman ◽  
A. S. Bayer
Keyword(s):  
Staphylococcus Aureus ◽  
Flow Cytometric Analysis ◽  
Flow Cytometric ◽  
Platelet Binding ◽  
Quantitative Flow

scholarly journals Flow cytometric analysis of herpes simplex virus type 1 susceptibility to acyclovir, ganciclovir, and foscarnet.

1997 ◽  
Vol 41 (12) ◽  
pp. 2686-2692 ◽  
Author(s):  
I Pavić ◽  
A Hartmann ◽  
A Zimmermann ◽  
D Michel ◽  
W Hampl ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Cytopathic Effect ◽  
Flow Cytometric Analysis ◽  
Flow Cytometric ◽  
Resistant Strains ◽  
Simplex Virus

We established a quantitative flow cytometric method for determination of herpes simplex virus type 1 (HSV-1) susceptibility to acyclovir (ACV), ganciclovir, and foscarnet in vitro. Susceptibility was defined in terms of the drug concentration which reduced the number of cells expressing HSV-1 glycoprotein C (gpC) with a fluorescence intensity of > or =10(2) by 50% (IC50). Flow cytometry allowed us to use a high (1.0) as well as a low (0.005) multiplicity of infection, and determination of the IC50 was possible after one or more viral replicative cycles. IC50s were dependent on virus input and on time postinfection. In mixture experiments, 1 to 2% resistant viruses added to a sensitive strain could be detected. The results obtained by flow cytometry showed a good qualitative correlation with those achieved by cytopathic effect inhibitory assay. However, flow cytometry might detect more quantitative differences in drug susceptibility, especially among resistant strains, as confirmed also by determination of intracellular drug phosphorylation. The mean IC50s for ACV-sensitive strains were 0.45 to 1.47 microM, and those for ACV-resistant strains were between 140 and 3,134 microM. Flow cytometric analysis was fast and accurate, automatizable, and highly reproducible. Flow cytometry may be a more powerful tool than standard cytopathic effect-based assays and could have advantages for the detection of low levels of drug resistance or mixtures of sensitive and resistant virus strains.

scholarly journals Flow cytometric analysis of virus-like particles and heterotrophic bacteria within coral-associated reef water

2006 ◽  
Vol 86 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Nicole L. Patten ◽  
Justin R. Seymour ◽  
James G. Mitchell
Keyword(s):  
Flow Cytometry ◽  
Bacterial Community ◽  
Heterotrophic Bacteria ◽  
Flow Cytometric Analysis ◽  
Water Layer ◽  
Dead Coral ◽  
Overlying Water ◽  
Virus Like Particles ◽  
Flow Cytometric ◽  
Diseased Coral

Using flow cytometry, two distinct populations of virus-like particles (VLP) and heterotrophic bacteria were defined within the 12 cm water layer immediately overlying healthy, diseased and dead acroporid corals. Bacterial abundances were similar in overlying water for all coral types, however, VLP were 30% higher above diseased corals than healthy or dead corals. Mean virus to bacteria ratios (VBR) were up to 30% higher above diseased corals than above healthy or dead coral or in distant water. Concomitant with increasing VLP concentrations within 5 cm of coral surfaces, VBR distributions were generally highest above healthy and diseased coral and depressed above dead coral. These results suggest fundamental shifts in the VLP and bacterial community in water associated with diseased corals.

scholarly journals Ethanol fixation of bladder irrigation specimens for flow cytometric analysis. A multiinstitutional study from the bladder cancer flow cytometry network

Cancer ◽  
1990 ◽  
Vol 63 (9) ◽  
pp. 1780-1783 ◽  
Author(s):  
Dane K. Hermansen ◽  
Myron R. Melamed ◽  
John S. Coon ◽  
Ronald S. Weinstein ◽  
Ralph Devere White ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Bladder Cancer ◽  
Flow Cytometric Analysis ◽  
Bladder Irrigation ◽  
Flow Cytometric

scholarly journals Application of Digital Image Analysis and Flow Cytometry To Enumerate Marine Viruses Stained with SYBR Gold

2001 ◽  
Vol 67 (2) ◽  
pp. 539-545 ◽  
Author(s):  
Feng Chen ◽  
Jing-rang Lu ◽  
Brian J. Binder ◽  
Ying-chun Liu ◽  
Robert E. Hodson
Keyword(s):  
Flow Cytometry ◽  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Flow Cytometric Analysis ◽  
Epifluorescence Microscopy ◽  
Flow Cytometric ◽  
Viral Particles ◽  
Sybr Gold ◽  
Nucleic Acid Stain

ABSTRACT A novel nucleic acid stain, SYBR Gold, was used to stain marine viral particles in various types of samples. Viral particles stained with SYBR Gold yielded bright and stable fluorescent signals that could be detected by a cooled charge-coupled device camera or by flow cytometry. The fluorescent signal strength of SYBR Gold-stained viruses was about twice that of SYBR Green I-stained viruses. Digital images of SYBR Gold-stained viral particles were processed to enumerate the concentration of viral particles by using digital image analysis software. Estimates of viral concentration based on digitized images were 1.3 times higher than those based on direct counting by epifluorescence microscopy. Direct epifluorescence counts of SYBR Gold-stained viral particles were in turn about 1.34 times higher than those estimated by the transmission electron microscope method. Bacteriophage lysates stained with SYBR Gold formed a distinct population in flow cytometric signatures. Flow cytometric analysis revealed at least four viral subpopulations for a Lake Erie sample and two subpopulations for a Georgia coastal sample. Flow cytometry-based viral counts for various types of samples averaged 1.1 times higher than direct epifluorescence microscopic counts. The potential application of digital image analysis and flow cytometry for rapid and accurate measurement of viral abundance in aquatic environments is discussed.

scholarly journals Flow cytometric analysis of bromodeoxyuridine-substituted cells stained with 33258 Hoechst.

1977 ◽  
Vol 25 (7) ◽  
pp. 927-934 ◽  
Author(s):  
S A Latt ◽  
Y S George ◽  
J W Gray
Keyword(s):  
Flow Cytometry ◽  
Cell Growth ◽  
Deoxyribonucleic Acid ◽  
Flow Cytometric Analysis ◽  
Chinese Hamster ◽  
Acid Synthesis ◽  
Whole Cells ◽  
Flow Cytometric ◽  
Deoxyribonucleic Acid Synthesis ◽  
Average Fluorescence

This paper describes a flow-cytometric application of the quenching of fluorescence from 33258 Hoechst stained Chinese hamster ovary-line cells due to the incorporation of 5-bromo-deoxyuridine (BrdU) into the cellular deoxyribonucleic acid. Cells were grown for 24 hr in medium containing BrdU in concentrations ranging from 1 x 10(-8) to 1 x 10(-4) M. For each concentration we measured the average fluorescence as determined by flow cytometry, the extent of BrdU substitution and the effect of the BrdU on cell growth. We determined that a BrdU concentration of 1 x 10(-5) M resulted in sufficient substitution to quench the fluorescence from 33258 Hoechst by a factor of 4, allowing discrimination between cycling and noncycling cells. The extent of BrdU substitution after growth for 24 hr in this concentration of BrdU was 64%. These data indicate the feasibility of detecting deoxyribonucleic acid synthesis in whole cells using the 33258 Hoechst-BrdU methodology.

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