Physiological investigations by image analysis

Pons, Marie‐Noëlle; Drouin, J.F.; Louvel, Liliane; Vanhoutte, Bert; Vivier, H.; Germain, Pierre

doi:10.1016/s0168-1656(98)00117-5

Cited by 21 publications

(15 citation statements)

References 49 publications

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“…Although the maximum hyphal area observed in 5 m 3 is considerably larger than the area observed in pilot-plant scale fermentors, it is quickly reduced to roughly 600 lm 2 after a few hours. However, the morphological behavior observed during the studied industrial cultivation of S.clavuligerus is similar to that observed by Pons et al [28] in Streptomyces ambofaciens with a complex medium: a fragmentation and a decrease of HGU were observed at the onset of the production of spiramycin. Similar findings have been described by Li et al for A. oryzae [29].…”

Section: Resultssupporting

confidence: 85%

Morphology and viability analysis of Streptomyces clavuligerus in industrial cultivation systems

Pinto

Vieira

Pons

et al. 2004

Bioprocess and Biosystems Engineering

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The effects of varying inoculum age and production scale upon the morphology and viability of Streptomyces clavuligerus were studied by analyzing visible and fluorescent light images acquired throughout pilot-plant and pre-industrial scale fermentations. Changes in production scale reveal that in 5 m(3) fermentors, the maximum hyphal area obtained is double the value obtained in 0.5 m(3) fermentors. It is probably due to the higher shear stresses acting upon hyphae in the 0.5 m(3) fermentor caused by higher tip speeds observed in these. The morphological quantification based on elongation and branching rates allowed fermentations to be pattern classified into distinct physiological time zones namely elongation, branching, fragmentation, etc. The general pattern observed for fermentations inoculated with late exponential phase inocula was similar to the pattern of fermentations run with stationary phase inocula except that both the elongation and branching periods started earlier in the former case. Using the available staining technique and image acquisition system, the viability seemed to be generally high and constant throughout the time course of all the studied fermentations.

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Section: Resultssupporting

confidence: 85%

Morphology and viability analysis of Streptomyces clavuligerus in industrial cultivation systems

Pinto

Vieira

Pons

et al. 2004

Bioprocess and Biosystems Engineering

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“…It has been often reported that, when cultivated on solid substrate, apical parts of filamentous species tend to become thinner, apparently due to substrate limitation, which induces the cell to increase its surface to volume ratio. Similar behavior has been observed in suspended media on fungi (Trichoderma reesei [151] and S. ambofaciens [153,154]) (Fig. 24).…”

Section: ) Pellet Convex Area -Core Convex Areasupporting

confidence: 83%

Biomass Quantification by Image Analysis

Pons

Vivier

1999

Bioanalysis and Biosensors for Bioprocess Monitoring

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Microbiologists have always rely on microscopy to examine microorganisms. When microscopy, either optical or electron-based, is coupled to quantitative image analysis, the spectrum of potential applications is widened: counting, sizing, shape characterization, physiology assessment, analysis of visual texture, motility studies are now easily available for obtaining information on biomass. In this chapter the main tools used for cell visualization as well as the basic steps of image treatment are presented. General shape descriptors can be used to characterize the cell morphology, but special descriptors have been defined for filamentous microorganisms. Physiology assessment is often based on the use of fluorescent dyes. The quantitative analysis of visual texture is still limited in bioengineering but the characterization of the surface of microbial colonies may open new prospects, especially for cultures on solid substrates. In many occasions, the number of parameters extracted from images is so large that data-mining tools, such as Principal Components Analysis, are useful for summarizing the key pieces of information.

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“…From this information it seems likely that nonviable compartments represent the weak links in a hyphae where fragmentation occurs. Given that these nonviable compartments can occur in the middle of, or at the end of, the growth phase (depending on the mode of substrate-limitation), one would expect to see similar modes of fragmentation in the literature, and indeed this is the case: Mid-growth phase fragmentation (Belmar-Beiny and Thomas, 1991;Warren et al, 1995;Sarra et al, 1996;Heydrian et al, 1999) and end-growth phase fragmentation (Belmar-Beiny and Thomas, 1990;Warren et al, 1995;Pons et al, 1998) seem to be typical behaviour for the actinomycetes in both de®ned and complex media.…”

Section: Discussionmentioning

confidence: 95%

Viability, strength, and fragmentation of Saccharopolyspora erythraea in submerged fermentation

Stocks

Thomas

2001

Biotech & Bioengineering

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Two fermentations of the commercially important erythromycin-producing filamentous bacterium Saccharopolyspora erythraea were conducted in defined media. One was glucose-limited and the other nitrate-limited. The viability of the hyphae was determined using the fluorescent stain BacLight (Molecular Probes, Eugene, OR). Also, the force required to strain hyphae to breakage was determined using micromanipulation and a sensitive force transducer. In both fermentations, fragmentation coincided with the appearance of regions in the mycelia with permeabilised membranes (considered nonviable). Under glucose-limitation, hyphal breaking force rose to 1,050 +/- 130 nN at the end of the growth phase and fell to an undetectable value as a result of glucose exhaustion. Under nitrate-limitation, hyphal breaking force fell from 900 +/- 160 nN during the growth phase to 550 +/- 40 nN in the stationary phase. In both cases image analysis showed that the dimensions of mycelia were of the same order, suggesting that the major factor influencing fragmentation was the appearance of nonviable regions (assumed to be weak). The location in which nonviable regions first appear within hyphae could not be determined because of their appearance coinciding with fragmentation.

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Physiological investigations by image analysis

Cited by 21 publications

References 49 publications

Morphology and viability analysis of Streptomyces clavuligerus in industrial cultivation systems

Morphology and viability analysis of Streptomyces clavuligerus in industrial cultivation systems

Biomass Quantification by Image Analysis

Viability, strength, and fragmentation of Saccharopolyspora erythraea in submerged fermentation

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