vendredi 24 avril 2009
par   G. Grégori

Barnett JM, Cuchens MA, Buchanan W (1984) Automated immunofluorescent speciation of oral bacteria using flow cytometry. J Dent Res 63 :1040-1042


Mixtures containing two bacterial species were analyzed using flow cytometric techniques. Light scattering characteristics of Streptococcus mutans and Actinomyces viscosus show unique profiles for pure cultures. However, the light scatter analysis of a mixture containing these two species demonstrates overlapping near the origin. Thus, light scatter analysis was not sufficient to speciate bacteria with different morphologies. Labeling of samples with species-specific immunofluorescent antibodies permitted speciation of mixtures. As the percentage of the bacterium to which the antibody is directed increased in a two-component mixture, fluorescent flow cytometric analysis showed a corresponding increase in the percentage of cells displaying fluorescent labeling. These methods could permit the rapid identification of bacteria from oral sites without culturing.

Bassoe CF, Solberg CO (1984) Phagocytosis of Staphylococcus aureus by human leukocytes : quantitation by a flow cytometric and a microbiological method. Acta Pathol Microbiol Immunol Scand [C] 92 :43-50


Phagocytosis of killed, fluorochrome stained or live Staphylococcus aureus by human leukocytes was measured by flow cytometry (FCM) or a microbiological method, respectively. The results were compared to those obtained by simulation using a prey-predator model. In the presence of an initial bacteria-to-phagocyte ratio of 4:1 to 160:1, the percentage of phagocytosing leukocytes was independent of the bacteria and phagocyte concentration. The number of phagocytosed or killed bacteria per phagocyte increased with increasing bacteria and decreasing phagocyte concentration. One per cent pooled human serum was sufficient for maximum phagocytosis to occur, but killing slightly increased in the presence of 10% pooled human serum. With medium or low initial bacteria-to-phagocyte ratios phagocytosis and killing closely corresponded to the results obtained by the prey-predator model. Maximally each phagocyte was associated with 80 bacteria (measured by FCM), about 45 being phagocytosed (internalized) and 40 killed. The model seems suitable for the simulation of phagocytosis and killing of S. aureus by human leukocytes.

Betz JW, Aretz W, Hartel W (1984) Use of flow cytometry in industrial microbiology for strain improvement programs. Cytometry 5 :145-150


A flow cytometry (FCM) system was chosen to analyze and sort microbiological samples, e.g., bacteria, bacterial spores, yeasts, and fungal spores, without major changes in the commercially available state. The system was further improved by addition of a stepping motor-driven scanning table that accepts standard petri dishes or microtiter plates. The electronics of the sorting system were changed to enable the sorter to deliver only one particle at a time, working in a "handshake" mode with the scanning table. Appropriate parameters, depending on the biological material and including all fluorescent stains that do not impair growth and productivity of cells were chosen to sort distinct bioparticles under aseptic conditions and to clone colonies or cultures out of them. A mutagenized sample of spores entering the germination cycle can be followed and thus provide a means to pick only viable growing cells despite the killing effect of the mutagen. One example of a typical strain improvement is illustrated. From a spore suspension of Rhizopus arrhizus, a subpopulation of morphologically different spores comprising about 5-10% of the whole population was cloned. From approximately 8,000 clones, 10 were isolated that produced approximately five- to six-fold the amount of fungal lipase activity, compared to the original strain or to reisolated clones from the mean population of clones.

Bjerknes R (1984) Flow cytometric assay for combined measurement of phagocytosis and intracellular killing of Candida albicans. J Immunol Methods 72 :229-241


A rapid quantitative flow cytometric (FCM) assay for the combined kinetic measurement of phagocytosis and intracellular killing of fluorescein-isothiocyanate (FITC) labelled Candida albicans is described. The fraction of phagocytosing leukocytes and the numbers of attached or internalized Candida albicans per phagocytosing leukocyte were quantified by FCM, using trypan blue and a fluorescence quenching technique. Results obtained by microscopy agreed with the FCM estimates of phagocytosis. Dead, but not live, Candida albicans stained by propidium iodide (PI). Thus, both viable and intracellularly killed fungi could be discriminated and measured by FCM. Phagocyte killing determined by the FCM assay correlated with killing measured by a standard microbiological test and by methylene blue staining. The method allows rapid and accurate testing of opsonic and phagocytic functions under both experimental and clinical conditions.

Kornman KS, Patters M, Kiel R, Marucha P (1984) Detection and quantitation of Bacteroides gingivalis in bacterial mixtures by means of flow cytometry. J Periodontal Res 19 :570-573


Lemay P, Collyn-D’Hooghe M (1984) Flow cytophotometric and time-lapse cinematographic study of human cells infected by adenovirus type 2 wild-type and two DNA-negative temperature-sensitive mutants. J Gen Virol 65 ( Pt 8) :1419-1423


Flow cytophotometry and time-lapse cinematography were used to study viral DNA synthesis and alteration of the cellular DNA content of human cells infected by adenovirus type 2 wild-type and two DNA-negative temperature-sensitive mutants. Cell populations with DNA contents greater than 4n (where n represents the normal haploid DNA content of cells) were found after infection and their origin is discussed with regard to cell cycle changes, viral DNA replication and cell fusion or endomitosis.