Monitoring population dynamics of the thermophilic Bacillus licheniformis CCMI 1034 in batch and continuous cultures using multi-parameter flow cytometry

Reis, Alberto; Silva, Teresa Lopes da; Kent, Christopher; Kosseva, Maria R.; Roseiro, J. Carlos; Hewitt, Christopher J.

doi:10.1016/j.jbiotec.2004.08.005

Cited by 38 publications

(33 citation statements)

References 23 publications

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“…In order to avoid problems associated with cell aggregation, sonication of samples was tested, as previously proposed (23,28). Samples were held in the "hot spot" of a sonication bath before analysis for different time intervals.…”

Section: Resultsmentioning

confidence: 99%

Use of Flow Cytometry To Follow the Physiological States of Microorganisms in Cider Fermentation Processes

Herrero

Quirós

Garcı́a

et al. 2006

Appl Environ Microbiol

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Analysis of microbiological samples from fermentation processes in the beverage industry (beer, wine, and cider) by traditional indirect, culture-based standard methods is timeconsuming, and the methods do not produce direct information about the physiological state of the microorganisms. Moreover, the plate-counting method detects only cells able to form colonies under the conditions of the medium that is used, ignoring the presence of cells that do not form colonies but are nevertheless metabolically active (6). As is known, standard laboratory culture media rarely resemble natural environmental conditions (32). The application of flow cytometry (FC) with fluorescent dyes is faster and more direct and has made it possible to distinguish stages beyond the classical definition of viability generally demonstrated by culturing (24). FC can be used to quantitatively measure the optical characteristics of cells as they pass, in single file, into a focused beam of light (for a review, see reference 33). As particles pass through the beam, three parameters are measured: forward light scatter, side angle light scatter, and fluorescence at selected wavelengths. Light scatter is related to cell mass, structure, surface properties, and the optical density of the internal medium. A variety of fluorescent dyes may be used to detect structural or functional cellular properties. In this way, different cellular functions, such as reproductive growth, metabolic activity, and membrane integrity, can be detected, allowing a definition of the term viable-but-not-culturable cells (VBNC) (24) (other authors have called them active but nonculturable). Previous studies have reported that there are two major adaptations that cells undergo during the formation of VBNC states: cell wall toughening and DNA condensation (29). The detection of metabolic activity provides presumptive evidence of reproductive growth by the demonstration of enzyme activity, such as esterases, along with membrane integrity. In the absence of metabolic activity, it is still possible to determine membrane integrity by either dye retention or dye exclusion, the latter using propidium iodide (PI). Cells without an intact membrane cannot maintain or generate the electrochemical gradient that generates the membrane potential and can be considered dead cells (24). The use of FC techniques was reported for the "at-line" study of Escherichia coli fermentations (14), which detected a considerable drop in cell viability (about 20%) during the latter stages of small-scale (5-liter), well-mixed fedbatch fermentations.Flow-cytometric applications using different dyes have been compared to standard methods to assess yeast cultures in baking, wine making, cider making, and brewing (1,5,7,8,10,11,17,19). The technique has also been used to study the membrane integrity of ethanol-stressed Oenococcus oeni cells (9). Most studies of FC applications have focused mainly on microorganims as pure cultures, and only a small number have analyzed mixed populations over time (30).The purp...

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Section: Resultsmentioning

confidence: 99%

Use of Flow Cytometry To Follow the Physiological States of Microorganisms in Cider Fermentation Processes

Herrero

Quirós

Garcı́a

et al. 2006

Appl Environ Microbiol

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“…Starter (2:1) showed the best viability rate (FL3 < FSC). In according to Reisa et al (2005), the flow cytometry approach is continuing to be useful for the study of bacterial population dynamics, providing important physiological information at the individual cell level that is difficult to obtain in any other way.…”

Section: Discussionmentioning

confidence: 99%

Fermentation profile of Saccharomyces cerevisiae and Candida tropicalis as starter cultures on barley malt medium

et al. 2014

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Saccharomyces cerevisiae C8-5 and Candida tropicalis F0-5 isolated from traditional sorghum beer were tested for kinetic parameters on barley malt extract, YPD (863 medium) and for alcohol production. The results showed that C. tropicalis has the highest maximum growth rate and the lowest doubling time. Values were 0.22 and 0.32 h −1 for maximum growth rate, 3 h 09 min and 2 h 09 min for doubling time respectively on barley malt extract and YPD. On contrary, glucose consumption was the fastest with S. cerevisiae (−0.36 and −0.722 g/l/h respectively on barley malt extract and YPD). When these two yeasts were used as starters in pure culture and co-culture at proportion of 1:1 and 2:1 (cell/cell) for barley malt extract fermentation, we noticed that maltose content increased first from 12.12 g/l to 13.62-16.46 g/l and then decreased. The highest increase was obtained with starter C. tropicalis + S. cerevisiae 2:1. On contrary, glucose content decreased throughout all the fermentation process. For all the starters used, the major part of the ethanol was produced at 16 h of fermentation. Values obtained in the final beers were 11.4, 11.6, 10.4 and 10.9 g/l for fermentation conducted with S. cerevisiae, C. tropicalis, C. tropicalis + S. cerevisiae 1:1 and C. tropicalis + S. cerevisiae 2:1. Cell viability measurement during the fermentation by using flow cytometry revealed that the lowest mean channel fluorescence for FL3 (yeast rate of death) was obtained with C. tropicalis + S. cerevisiae 2:1 after 48 h of fermentation.

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“…Similarly under-appreciated is the paucity that the resistance of microorganisms to external stresses is influenced by their micro-environment [112], an obvious example being their interaction with the surface of their supporting substrate [113]. Future studies are likely to include detailed characterisation of both plasma and microbial sample conditions.…”

Section: Reactive Plasma Species and Their Biological Targetsmentioning

confidence: 99%

Plasmas meet nanoparticles—where synergies can advance the frontier of medicine

Kong¹,

Keidar²,

Ostrikov³

2011

J. Phys. D: Appl. Phys.

107

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To cite this version:M G Kong, M Keidar, K Ostrikov. Plasmas meet nanoparticleswhere synergies can advance the frontier of medicine. Journal of Physics D: Applied Physics, IOP Publishing, 2011, 44 (17) AbstractNanoparticles and low-temperature plasmas have been developed, independently and often along different routes, to tackle the same set of challenges in biomedicine. There are intriguing similarities and contrasts in their interactions with cells and living tissues, and these are reflected directly in the characteristics and scope of their intended therapeutic solutions, in particular their chemical reactivity, selectivity against pathogens and cancer cells, safety to healthy cells and tissues, and targeted delivery to diseased tissues. Time has come to ask the inevitable question of possible plasma-nanoparticle synergy and the related benefits to the development of effective, selective, and safe therapies for modern medicine. This perspective article offers a detailed review of the strengths and weakenesses of nanomedicine and plasma medicine as a stand-alone technology, and then provides a critical analysis of some of the major opportunities enabled by synergising the nanotechnology and the plasma technology. It is shown that the plasma-nanoparticle synergy is best captured through the plasma nanotechnology and its benefits for medicine are highly promising.

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Monitoring population dynamics of the thermophilic Bacillus licheniformis CCMI 1034 in batch and continuous cultures using multi-parameter flow cytometry

Cited by 38 publications

References 23 publications

Use of Flow Cytometry To Follow the Physiological States of Microorganisms in Cider Fermentation Processes

Use of Flow Cytometry To Follow the Physiological States of Microorganisms in Cider Fermentation Processes

Fermentation profile of Saccharomyces cerevisiae and Candida tropicalis as starter cultures on barley malt medium

Plasmas meet nanoparticles—where synergies can advance the frontier of medicine

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