Structural studies of an emulsion-stabilizing exopolysaccharide produced by an adhesive, hydrophobic Rhodococcus strain

Neu, Thomas R.; Dengler, Thomas J.; Jann, Barbara; Poralla, Karl

doi:10.1099/00221287-138-12-2531

Cited by 47 publications

(19 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some Rhodococcus strains produce biosurfactant molecules in response to n-alkanes. These molecules are predominantly glycolipids (10), but other types have also been reported (9,12,14). S-2 EPS is a high-molecularweight complex of acidic polysaccharides and lipids (our preliminary results) and, therefore, different from previously reported Rhodococcus biosurfactants.…”

contrasting

confidence: 40%

Relationships between Colony Morphotypes and Oil Tolerance in Rhodococcus rhodochrous

Iwabuchi

Sunairi

Anzai

et al. 2000

Appl Environ Microbiol

View full text Add to dashboard Cite

A mucoidal strain of Rhodococcus rhodochrous was resistant to 10% (vol/vol) n-hexadecane, while its rough derivatives were sensitive. When the extracellular polysaccharide (EPS) produced by the mucoidal strain was added to cultures of the rough strains, the rough strains gained resistance to n-hexadecane. Thus, EPS confer tolerance to n-hexadecane in members of the genus Rhodococcus.The genus Rhodococcus is a group of bacteria that exhibit a diverse range of metabolic activities. Some rhodococci have the ability to degrade a variety of organic compounds, including man-made xenobiotic compounds such as polychlorinated biphenyls, while others are capable of degrading numerous aliphatic or aromatic hydrocarbons (4,6,17,18). We prepared the aromatic fraction (AF) of Arabian light crude oil by silica gel chromatography as indicated in Table 1 (SWYAF). None of the strains tested grow in SWY, but six strains exhibited significant growth in SWYAF. All six of these strains were mucoidal in colony morphotype (Table 1).Nineteen of the 75 strains tested showed spontaneous rough-smooth colony morphotype changes at high frequencies. Three of these strains, Rhodococcus rhodochrous ATCC 17041, ATCC 19140, and ATCC 19150, were selected, and mucoidal derivatives were obtained from the original strains. Subsequently, rough derivatives were obtained from the mucoidal variants. The mucoidal clones of R. rhodochrous ATCC 17041, ATCC 19140, and ATCC 19150 showed good growth on SWYAF, whereas the parental strains and the rough derivatives of the mucoidal variants showed no or poor growth on SWYAF.These data suggested that there was an association between mucoidal morphology and the ability to grow on the AF of the crude oil. To investigate further, we employed three colony morphology mutants, S-2, R-1, and R-2, derived from R. rhodochrous CF222 (11, 16). Mucoidal strain S-2 grew well on SWYAF, whereas rough strains R-1 and R-2 did not (Fig. 1A). Plasmid pK4I-7 transformed S-2 from mucoidal to rough colony morphology, and production of extracellular polysaccharide (EPS) was suppressed in the resulting rough transformants (7). Growth of these transformants was inhibited greatly in SWYAF, supporting the hypothesis that there is an association between mucoidal morphology and the ability to grow on the AF.Strains S-2, R-1, and R-2 grew on YG (1% [wt/vol] glucose and 1% [wt/vol] yeast extract dissolved in distilled water, pH 7.2). Mucoidal strain S-2 showed good growth on YG containing 1% (vol/vol) AF (YGAF), while growth of rough strain R-2 was greatly inhibited by the AF. Growth of rough strain R-1 was also inhibited by the AF but to a lesser extent (Fig. 1B). From these observations, we concluded that the rough strains could not grow on the AF because they are sensitive to it.To characterize the tolerance of Rhodococcus strains to various hydrocarbons, an organic solvent tolerance test was performed as described by Aono et al. (2), and the results are shown in Table 2. Mucoidal strain S-2 showed good growth on plates overlaid with n-d...

show abstract

contrasting

confidence: 40%

Relationships between Colony Morphotypes and Oil Tolerance in Rhodococcus rhodochrous

Iwabuchi

Sunairi

Anzai

et al. 2000

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…In several Gram‐positive bacteria, including B. subtilis , membrane glycolipids have been implicated in biofilm formation, but an explanation of the mechanism by which these lipids affect biofilm formation is lacking (Lazarevic et al ., ; Theilacker et al ., ). In addition to the presence of lipids, the hydrophobic characteristics of the biofilm have been attributed to the covalent modification of extracellular polymeric molecules with FA‐related molecules (Neu and Poralla, ; Neu et al ., ) and the secretion of biosurfactants to the ECM of the biofilm (Davey et al ., ; López and Kolter, ; Epstein et al ., ). The ECM of the biofilm made by B. subtilis contains an exopolysaccharide (EPS) of an incompletely known structure (EPS) and the proteins BslA (formerly named YuaB; Kobayashi and Iwano, ; Kovács et al ., ) and TasA (an amyloid protein with antimicrobial properties, Branda et al ., ; ).…”

Section: Resultsmentioning

confidence: 99%

Spo0A links de novo fatty acid synthesis to sporulation and biofilm development in Bacillus subtilis

Pedrido

Oña

Ramirez

et al. 2012

Molecular Microbiology

105

View full text Add to dashboard Cite

SummaryDuring sporulation in Bacillus subtilis, the committedcell undergoes substantial membrane rearrangements to generate two cells of different sizes and fates: the mother cell and the forespore. Here, we demonstrate that the master transcription factor Spo0A reactivates lipid synthesis during development. Maximal Spo0A-dependent lipid synthesis occurs during the key stages of asymmetric division and forespore engulfment. Spo0A reactivates the accDA operon that encodes the carboxylase component of the acetylCoA carboxylase enzyme, which catalyses the first and rate-limiting step in de novo lipid biosynthesis, malonyl-CoA formation. The disruption of the Spo0A-binding box in the promoter region of accDA impairs its transcriptional reactivation and blocks lipid synthesis. The Spo0A-insensitive accDA 0A cells were proficient in planktonic growth but defective in sporulation (s E activation) and biofilm development (cell cluster formation and water repellency). Exogenous fatty acid supplementation to accDA 0A cells overcomes their inability to synthesize lipids during development and restores sporulation and biofilm proficiencies. The transient exclusion of the lipid synthesis regulon from the forespore and the known compartmentalization of Spo0A and ACP in the mother cell suggest that de novo lipid synthesis is confined to the mother cell. The significance of the Spo0A-controlled de novo lipid synthesis during B. subtilis development is discussed.

show abstract

“…Water retained in EPS incubated for 36 h enhances the robustness of the EPS, thereby protecting the enclosed cells. Slight shifts in the approach curves after continuous compressions indicate little water loss, and EPS of cells incubated for 36 h are more resilient to normal stress than those incubated for 6 h. Rhodococcal polysaccharides, which are present in both the exponential and the stationary phase contain rhamnose, galactose, glucose, and glucuronic acid [72], of which rhamnose is considered to be the least water-soluble.…”

Section: Discussionmentioning

confidence: 99%

Effect of extracellular polymeric substances on the mechanical properties of Rhodococcus

Pen

Zhang

Morales-García

et al. 2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

The mechanical properties of Rhodococcus RC291 were measured using force spectroscopy equipped with a bacterial cell probe. Rhodococcal cells in the late growth stage of development were found to have greater adhesion to a silicon oxide surface than those in the early growth stage. This is because there are more extracellular polymeric substances (EPS) that contain nonspecific binding sites available on the cells of late growth stage. It is found that EPS in the late exponential phase are less densely bound but consist of chains able to extend further into their local environment, while the denser EPS at the late stationary phase act more to sheath the cell. Contraction and extension of the EPS could change the density of the binding sites, and therefore affect the magnitude of the adhesion force between the EPS and the silicon oxide surface. By treating rhodococcal EPS as a surface-grafted polyelectrolyte layer and using scaling theory, the interaction between EPS and a solid substrate was modelled for the cell approaching the surface which revealed that EPS possess a large capacity to store charge. Changing the pH of the surrounding medium acts to change the conformation of EPS chains.

show abstract

Structural studies of an emulsion-stabilizing exopolysaccharide produced by an adhesive, hydrophobic Rhodococcus strain

Cited by 47 publications

References 29 publications

Relationships between Colony Morphotypes and Oil Tolerance in Rhodococcus rhodochrous

Relationships between Colony Morphotypes and Oil Tolerance in Rhodococcus rhodochrous

Spo0A links de novo fatty acid synthesis to sporulation and biofilm development in Bacillus subtilis

Effect of extracellular polymeric substances on the mechanical properties of Rhodococcus

Contact Info

Product

Resources

About