Low-Load Compression Testing: a Novel Way of Measuring Biofilm Thickness

Paramonova, Ekaterina; Jong, Ed de; Krom, Bastiaan P.; Mei, Henny C. van der; Busscher, Henk J.; Sharma, Prashant K.

doi:10.1128/aem.00935-07

Cited by 35 publications

(30 citation statements)

References 18 publications

(12 reference statements)

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“…5A). Direct measurement of biofilm thickness with an LLCT (25) revealed that the cat2 null mutant formed 30% thinner biofilms compared to the wild-type strain (350 and 250 m thick, respectively) and that biofilm formation was partially restored in the complemented strain (300 m thick), which is in line with the gene dosage effect (Fig. 5B).…”

Section: Vol 7 2008 Role Of Cat2p In Acetyl-coa Transport In C Albsupporting

confidence: 63%

Carnitine-Dependent Transport of Acetyl Coenzyme A in Candida albicans Is Essential for Growth on Nonfermentable Carbon Sources and Contributes to Biofilm Formation

Strijbis¹,

Roermund

Visser

et al. 2008

Eukaryot Cell

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In eukaryotes, acetyl coenzyme A (acetyl-CoA) produced during peroxisomal fatty acid ␤-oxidation needs to be transported to mitochondria for further metabolism. Two parallel pathways for acetyl-CoA transport have been identified in Saccharomyces cerevisiae; one is dependent on peroxisomal citrate synthase (Cit), while the other requires peroxisomal and mitochondrial carnitine acetyltransferase (Cat) activities. Here we show that the human fungal pathogen Candida albicans lacks peroxisomal Cit, relying exclusively on Cat activity for transport of acetyl units. Deletion of the CAT2 gene encoding the major Cat enzyme in C. albicans resulted in a strain that had lost both peroxisomal and mitochondrion-associated Cat activities, could not grow on fatty acids or C 2 carbon sources (acetate or ethanol), accumulated intracellular acetyl-CoA, and showed greatly reduced fatty acid ␤-oxidation activity. The cat2 null mutant was, however, not attenuated in virulence in a mouse model of systemic candidiasis. These observations support our previous results showing that peroxisomal fatty acid ␤-oxidation activity is not essential for C. albicans virulence. Biofilm formation by the cat2 mutant on glucose was slightly reduced compared to that by the wild type, although both strains grew at the same rate on this carbon source. Our data show that C. albicans has diverged considerably from S. cerevisiae with respect to the mechanism of intracellular acetyl-CoA transport and imply that carnitine dependence may be an important trait of this human fungal pathogen.

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Section: Vol 7 2008 Role Of Cat2p In Acetyl-coa Transport In C Albsupporting

confidence: 63%

Carnitine-Dependent Transport of Acetyl Coenzyme A in Candida albicans Is Essential for Growth on Nonfermentable Carbon Sources and Contributes to Biofilm Formation

Strijbis¹,

Roermund

Visser

et al. 2008

Eukaryot Cell

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“…Upon application of DNase I, biofilms of C. albicans can be only partially detached from surfaces. In a manner similar to bacterial biofilms, Candida EPS is known to play an important role in drug resistance.In this study, biofilms of mutant chk1/chk1 (Chk24), the gene-reconstructed chk1/CHK1 (Chk23) and wild-type CHK1/CHK1 (Caf2-1) C. albicans strains, along with two non-albicans Candida species, C. tropicalis and C. parapsilosis, isolated from used voice prostheses, were subjected to compression forces in a uniaxial low-load compression tester (LLCT) (Paramonova et al, 2007). Effects of increasing the shear during growth were evaluated only for C. albicans Caf2-1.…”

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confidence: 99%

Hyphal content determines the compression strength of Candida albicans biofilms

et al. 2009

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Candida albicans is the most frequently isolated human fungal pathogen among species causing biofilm-related clinical infections. Mechanical properties of Candida biofilms have hitherto been given no attention, despite the fact that mechanical properties are important for selection of treatment or dispersal of biofilm organisms due to a bodily fluid flow. The aim of this study was to identify the factors that determine the compression strength of Candida biofilms. Biofilms of C. albicans wild-type parental strain Caf2-1, mutant strain Chk24 lacking Chk1p [known to be involved in regulation of morphogenesis (yeast-to-hyphae transition)] and gene-reconstructed strain Chk23 were evaluated for their resistance to compression, along with biofilms of Candida tropicalis GB 9/9 and Candida parapsilosis GB 2/8, derived from used voice prosthetic biofilms. Additionally, cell morphologies within the biofilm, cell-surface hydrophobicities and extracellular polymeric substance composition were determined. Our results suggest that the hyphae-to-yeast ratio influences the compression strength of C. albicans biofilms. Biofilms with a hyphal content .50 % possessed significantly higher compressive strength and were more difficult to destroy by vortexing and sonication than biofilms with a lower hyphal content. However, when the amount of extracellular DNA (eDNA) in biofilms of C. albicans Caf2-1 and Chk24 increased, biofilm strength declined, suggesting that eDNA may influence biofilm integrity adversely. INTRODUCTIONBiofilms are populations of micro-organisms embedded in an extracellular polymeric substance (EPS) (Costerton et al., 1987). The biofilm mode of growth is beneficial for micro-organisms, as it provides a higher degree of stability than a planktonic existence, and organisms within a biofilm are more resistant to environmental challenges (Hall-Stoodley et al., 2004), such as low nutrient availability, high fluid shear and antibiotic and antimicrobial agents (Baker & Banfield, 2003;Battin et al., 2001;Donlan & Costerton, 2002;Elasri & Miller, 1999;Stewart & Costerton, 2001). The damage caused by the formation of biofilms is a widespread problem, ranging from pipeline corrosion and biofouling of ship hulls and food-processing equipment to clinical infections, such as endocarditis and cystic fibrosis pneumonia (Beech & Gaylarde, 1999;Callow & Callow, 2002;Costerton et al., 1999;Kumar & Anand, 1998). Many clinical infections due to biofilms are implant-related and occur when micro-organisms adhere to the surfaces of biomaterials used in, for example, prosthetic heart valves, voice prostheses, joint replacements, vascular grafts and urinary catheters (Costerton et al., 1999;Donlan, 2001).Biofilms can consist of bacterial or fungal species or a mixture of both. For instance, in the case of vascular catheter-related infections or voice prosthetic biofilms, the most commonly isolated microbial species are Grampositive Staphylococcus epidermidis and Staphylococcus aureus, and the fungus Candida albicans (Hampton & Sherertz, 19...

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“…Biofilms can be grown ex situ and transplanted to the rheometer, either intact on plates [41,66] or by a destructive process [55,104], or the rheometer modified to permit growth in situ [69,70]. Macrorheometry can extract bulk properties [68,82] but is not well suited to studying heterogeneities.…”

Section: Experimental Biofilm Rheologymentioning

confidence: 99%

Biomechanical Analysis of Infectious Biofilms

Head

2016

Biophysics of Infection

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The removal of infectious biofilms from tissues or implanted devices and their transmission through fluid transport systems depends in part of the mechanical properties of their polymeric matrix. Linking the various physical and chemical microscopic interactions to macroscopic deformation and failure modes promises to unveil design principles for novel therapeutic strategies targeting biofilm eradication, and provide a predictive capability to accelerate the development of devices, water lines etc. that minimise microbial dispersal. Here our current understanding of biofilm mechanics is appraised from the perspective of biophysics, with an emphasis on constitutive modelling that has been highly successful in soft matter. Fitting rheometric data to viscoelastic models has quantified linear and non-linear stress relaxation mechanisms, how they vary between species and environments, and how candidate chemical treatments alter the mechanical response. The rich interplay between growth, mechanics and hydrodynamics is just becoming amenable to computational modelling and promises to provide unprecedented characterisation of infectious biofilms in their native state.

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Low-Load Compression Testing: a Novel Way of Measuring Biofilm Thickness

Cited by 35 publications

References 18 publications

Carnitine-Dependent Transport of Acetyl Coenzyme A in Candida albicans Is Essential for Growth on Nonfermentable Carbon Sources and Contributes to Biofilm Formation

Carnitine-Dependent Transport of Acetyl Coenzyme A in Candida albicans Is Essential for Growth on Nonfermentable Carbon Sources and Contributes to Biofilm Formation

Hyphal content determines the compression strength of Candida albicans biofilms

Biomechanical Analysis of Infectious Biofilms

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