Image analysis of the morphology of filamentous micro-organisms

Cox, Philip W. L.; Paul, Goutam; Thomas, C. R.

doi:10.1099/00221287-144-4-817

Cited by 100 publications

(72 citation statements)

References 61 publications

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“…The usual structure of fungal pellets is a core of highly entangled, densely packed hyphae surrounded to a greater or lesser extent by more loosely packed radiating hyphae (20)(21). As can be seen in Fig.…”

Section: Vol 9 2010mentioning

confidence: 95%

Two Components of a velvet -Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

et al. 2010

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Penicillium chrysogenum is the industrial producer of the antibiotic penicillin, whose biosynthetic regulation is barely understood. Here, we provide a functional analysis of two major homologues of the velvet complex in P. chrysogenum, which we have named P. chrysogenum velA (PcvelA) and PclaeA. Data from array analysis using a ⌬PcvelA deletion strain indicate a significant role of PcVelA on the expression of biosynthesis and developmental genes, including PclaeA. Northern hybridization and high-performance liquid chromatography quantifications of penicillin titers clearly show that both PcVelA and PcLaeA play a major role in penicillin biosynthesis in a producer strain that underwent several rounds of UV mutagenesis during a strain improvement program. Both regulators are further involved in different developmental processes. While PcvelA deletion leads to light-independent conidial formation, dichotomous branching of hyphae, and pellet formation in shaking cultures, a ⌬PclaeA strain shows a severe impairment in conidiophore formation under both light and dark conditions. Bimolecular fluorescence complementation assays provide evidence for a velvet-like complex in P. chrysogenum, with structurally conserved components that have distinct developmental roles, illustrating the functional plasticity of these regulators in genera other than Aspergillus.

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Section: Vol 9 2010mentioning

confidence: 95%

Two Components of a velvet -Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

et al. 2010

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“…However, commercial exploitation of these biocatalysts is often hampered because of the lack of knowledge about their production parameters in industrial conditions. Mycelial morphology in submerged cultures is usually classified into two different forms: individual filamentous mycelia (dispersed form) and spherical colonies called pellets (Prosser, 1995;Cox et al, 1998). The disadvantages of dispersed mycelial growth include increased wall growth and reduction in efficiency of mixing and oxygen supply to the cells due to increased viscosity of the medium (Schügerl et al 1983).…”

Section: Introductionmentioning

confidence: 99%

In situ localization of manganese peroxidase production in mycelial pellets of Phanerochaete chrysosporium

Jimenez-Tobon

Kurzątkowski²,

Rozbicka³

et al. 2003

Microbiology

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The ultrastructure of Phanerochaete chrysosporium hyphae from pellets in submerged liquid cultures was investigated in order to learn more about the interrelation between fungal architecture and manganese peroxidase (MnP) production. At day 2 of cultivation, some subapical regions of hyphae in the outer and middle zones of the pellet initiated differentiation into intercalary thick-walled chlamydospore-like cells of about 10 mm diameter. At the periphery of the cytoplasm of these cells, a large number of mitochondria and Golgi-like vesicles were observed. The sites of MnP production were localized at different stages of cultivation by an immunolabelling procedure. The immunomarker of MnP was mainly concentrated in the chlamydospore-like cells and principally distributed in Golgi-like vesicles located at the periphery of the cytoplasm. The apices of hyphae in the outer layer of the pellets were apparently minor sites of MnP production. Maximal MnP release into the culture supernatant coincided with apparent autolysis of the chlamydospore-like cells. Production of extracellular autolytic chitinase and protease coincided with the disappearance of these structures from the pellets. The chlamydospore-like cells observed in the mycelial pellets of P. chrysosporium could be metabolically active entities operating as an enzyme reservoir, delivering their content into the surrounding medium possibly by an enzyme-mediated autolytic process.

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“…With the development of automated image analysis techniques, in the 1990's, a considerable quantity of information about microorganism morphology has been obtained, with faster and more accurate results than the ones obtained with the earlier time-consuming manual methods, consisting in measurements from photographs (1,3,10). Nowadays, image analysis is a very useful technique to assess morphology during cultivations.…”

Section: Introductionmentioning

confidence: 99%

Applications of image analysis in the characterization of Streptomyces olindensis in submerged culture

Pamboukian¹,

Guimarães²,

Facciotti³

2002

Braz. J. Microbiol.

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The morphology of Streptomyces olindensis (producer of retamycin, an antitumor antibiotic) grown in submerged culture was assessed by image analysis. The morphology was differentiated into four classes: pellets, clumps (or entangled filaments), branched and unbranched free filaments. Four morphological parameters were initially considered (area, convex area, perimeter, and convex perimeter) but only two parameters (perimeter and convex perimeter) were chosen to automatically classify the cells into the four morphological classes, using histogram analysis. Each morphological class was evaluated during growth carried out in liquid media in fermenter or shaker. It was found that pellets and clumps dominated in early growth stages in fermenter (due to the inoculum coming from a shaker cultivation) and that during cultivation, the breakage of pellets and clumps caused an increase in the percentage of free filaments. The criteria of morphological classification by image analysis proposed were useful to quantify the percentage of each morphological class during fermentations and may help to establish correlations between antibiotic production and microorganism morphology.

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Image analysis of the morphology of filamentous micro-organisms

Cited by 100 publications

References 61 publications

Two Components of a velvet -Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

Two Components of a velvet -Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

In situ localization of manganese peroxidase production in mycelial pellets of Phanerochaete chrysosporium

Applications of image analysis in the characterization of Streptomyces olindensis in submerged culture

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