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Atomic force microscopy reveals a morphological differentiation of chromobacterium violaceum cells associated with biofilm development and directed by N-hexanoyl-L-homoserine lactone.

Kamaeva AA, Vasilchenko AS, Deryabin DG - PLoS ONE (2014)

Bottom Line: We report for the first time the unusual morphological differentiation of C. violaceum cells, associated with biofilm development and directed by the QS autoinducer.With increasing bacterial growth, polymer matrix extrusions formed in place of invaginations, whereas mutant cells were covered with a diffusely distributed extracellular substance.Thus, quorum sensing in C. violaceum involves a morphological differentiation that organises biofilm formation and leads to a highly differentiated matrix structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Orenburg State University, Orenburg, Russia; RSE «Republican Collection of Microorganisms», Astana, Republic of Kazakhstan.

ABSTRACT
Chromobacterium violaceum abounds in soil and water ecosystems in tropical and subtropical regions and occasionally causes severe and often fatal human and animal infections. The quorum sensing (QS) system and biofilm formation are essential for C. violaceum's adaptability and pathogenicity, however, their interrelation is still unknown. C. violaceum's cell and biofilm morphology were examined by atomic force microscopy (AFM) in comparison with growth rates, QS-dependent violacein biosynthesis and biofilm biomass quantification. To evaluate QS regulation of these processes, the wild-type strain C. violaceum ATCC 31532 and its mini-Tn5 mutant C. violaceum NCTC 13274, cultivated with and without the QS autoinducer N-hexanoyl-L-homoserine lactone (C6-HSL), were used. We report for the first time the unusual morphological differentiation of C. violaceum cells, associated with biofilm development and directed by the QS autoinducer. AFM revealed numerous invaginations of the external cytoplasmic membrane of wild-type cells, which were repressed in the mutant strain and restored by exogenous C6-HSL. With increasing bacterial growth, polymer matrix extrusions formed in place of invaginations, whereas mutant cells were covered with a diffusely distributed extracellular substance. Thus, quorum sensing in C. violaceum involves a morphological differentiation that organises biofilm formation and leads to a highly differentiated matrix structure.

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Related in: MedlinePlus

Cross sections (a–c), where x-axis is a heights of relief points and y-axis is a cross sections distance; and roughness values (d–f) of biofilm surfaces, produced by wild-type strain C. violaceum ATCC 31532 (a, d) and mutant strain C. violaceum NCTC 13274, growing without (b, e) and with 0.1 µM C6-HSL (c, f).
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pone-0103741-g006: Cross sections (a–c), where x-axis is a heights of relief points and y-axis is a cross sections distance; and roughness values (d–f) of biofilm surfaces, produced by wild-type strain C. violaceum ATCC 31532 (a, d) and mutant strain C. violaceum NCTC 13274, growing without (b, e) and with 0.1 µM C6-HSL (c, f).

Mentions: Figure 6 shows that C. violaceum ATCC 31532 produced relatively smooth biofilm consisting of tightly associated polymer blocks, and the average surface roughness was only 13.0±2.65 nm.


Atomic force microscopy reveals a morphological differentiation of chromobacterium violaceum cells associated with biofilm development and directed by N-hexanoyl-L-homoserine lactone.

Kamaeva AA, Vasilchenko AS, Deryabin DG - PLoS ONE (2014)

Cross sections (a–c), where x-axis is a heights of relief points and y-axis is a cross sections distance; and roughness values (d–f) of biofilm surfaces, produced by wild-type strain C. violaceum ATCC 31532 (a, d) and mutant strain C. violaceum NCTC 13274, growing without (b, e) and with 0.1 µM C6-HSL (c, f).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128650&req=5

pone-0103741-g006: Cross sections (a–c), where x-axis is a heights of relief points and y-axis is a cross sections distance; and roughness values (d–f) of biofilm surfaces, produced by wild-type strain C. violaceum ATCC 31532 (a, d) and mutant strain C. violaceum NCTC 13274, growing without (b, e) and with 0.1 µM C6-HSL (c, f).
Mentions: Figure 6 shows that C. violaceum ATCC 31532 produced relatively smooth biofilm consisting of tightly associated polymer blocks, and the average surface roughness was only 13.0±2.65 nm.

Bottom Line: We report for the first time the unusual morphological differentiation of C. violaceum cells, associated with biofilm development and directed by the QS autoinducer.With increasing bacterial growth, polymer matrix extrusions formed in place of invaginations, whereas mutant cells were covered with a diffusely distributed extracellular substance.Thus, quorum sensing in C. violaceum involves a morphological differentiation that organises biofilm formation and leads to a highly differentiated matrix structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Orenburg State University, Orenburg, Russia; RSE «Republican Collection of Microorganisms», Astana, Republic of Kazakhstan.

ABSTRACT
Chromobacterium violaceum abounds in soil and water ecosystems in tropical and subtropical regions and occasionally causes severe and often fatal human and animal infections. The quorum sensing (QS) system and biofilm formation are essential for C. violaceum's adaptability and pathogenicity, however, their interrelation is still unknown. C. violaceum's cell and biofilm morphology were examined by atomic force microscopy (AFM) in comparison with growth rates, QS-dependent violacein biosynthesis and biofilm biomass quantification. To evaluate QS regulation of these processes, the wild-type strain C. violaceum ATCC 31532 and its mini-Tn5 mutant C. violaceum NCTC 13274, cultivated with and without the QS autoinducer N-hexanoyl-L-homoserine lactone (C6-HSL), were used. We report for the first time the unusual morphological differentiation of C. violaceum cells, associated with biofilm development and directed by the QS autoinducer. AFM revealed numerous invaginations of the external cytoplasmic membrane of wild-type cells, which were repressed in the mutant strain and restored by exogenous C6-HSL. With increasing bacterial growth, polymer matrix extrusions formed in place of invaginations, whereas mutant cells were covered with a diffusely distributed extracellular substance. Thus, quorum sensing in C. violaceum involves a morphological differentiation that organises biofilm formation and leads to a highly differentiated matrix structure.

Show MeSH
Related in: MedlinePlus