scholarly journals Polysaccharide production and biofilm formation by Pseudomonas fluorescen: effects of pH and surface material

1994 ◽  
Vol 2 (1-3) ◽  
pp. 41-46 ◽  
Author(s):  
R. Oliveira ◽  
L. Melo ◽  
A. Oliveira ◽  
R. Salgueiro
Keyword(s):  
Biofilm Formation ◽  
Surface Material ◽  
Polysaccharide Production ◽  
Effects Of Ph

scholarly journals Effects of pH on the Properties of Membrane Vesicles Including Glucosyltransferase in Streptococcus mutans

2021 ◽  
Vol 9 (11) ◽  
pp. 2308
Author(s):  
Yusuke Iwabuchi ◽  
Tomoyo Nakamura ◽  
Yasuka Kusumoto ◽  
Ryoma Nakao ◽  
Tsutomu Iwamoto ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Membrane Vesicles ◽  
Extracellular Dna ◽  
Tooth Surface ◽  
Initial Ph ◽  
Effects Of Ph ◽  
Low Levels ◽  
Quantitative Changes ◽  
Biofilm Development

Streptococcus mutans releases membrane vesicles (MVs) and induces MV-dependent biofilm formation. Glucosyltransferases (Gtfs) are bound to MVs and contribute to the adhesion and glucans-dependent biofilm formation of early adherent bacteria on the tooth surface. The biofilm formation of S. mutans may be controlled depending on whether the initial pH tends to be acidic or alkaline. In this study, the characteristics and effects of MVs extracted from various conditions {(initial pH 6.0 and 8.0 media prepared with lactic acid (LA) and acetic acid (AA), and with NaOH (NO), respectively)} on the biofilm formation of S. mutans and early adherent bacteria were investigated. The quantitative changes in glucans between primary pH 6.0 and 8.0 conditions were observed, associated with different activities affecting MV-dependent biofilm formation. The decreased amount of Gtfs on MVs under the initial pH 6.0 conditions strongly guided low levels of MV-dependent biofilm formation. However, in the initial pH 6.0 and 8.0 solutions prepared with AA and NO, the MVs in the biofilm appeared to be formed by the expression of glucans and/or extracellular DNA. These results suggest that the environmental pH conditions established by acid and alkaline factors determine the differences in the local pathogenic activities of biofilm development in the oral cavity.

scholarly journals The Transcriptional Regulator BpsR Controls the Growth ofBordetella bronchisepticaby Repressing Genes Involved in Nicotinic Acid Degradation

2018 ◽  
Vol 200 (12) ◽  
pp. e00712-17 ◽  
Author(s):  
Manita Guragain ◽  
Jamie Jennings-Gee ◽  
Natalia Cattelan ◽  
Mary Finger ◽  
Matt S. Conover ◽  
...  
Keyword(s):  
Nicotinic Acid ◽  
Biofilm Formation ◽  
Transcriptional Control ◽  
Bordetella Bronchiseptica ◽  
Negative Regulator ◽  
Growth Defect ◽  
Content Type ◽  
Polysaccharide Production ◽  
Expression Of Genes

ABSTRACTMany of the pathogenic species of the genusBordetellahave an absolute requirement for nicotinic acid (NA) for laboratory growth. These Gram-negative bacteria also harbor a gene cluster homologous to theniccluster ofPseudomonas putidawhich is involved in the aerobic degradation of NA and its transcriptional control. We report here that BpsR, a negative regulator of biofilm formation and Bps polysaccharide production, controls the growth ofBordetella bronchisepticaby repressing the expression ofnicgenes. The severe growth defect of the ΔbpsRstrain in Stainer-Scholte medium was restored by supplementation with NA, which also functioned as an inducer ofnicgenes at low micromolar concentrations that are usually present in animals and humans. Purified BpsR protein bound to thenicpromoter region, and its DNA binding activity was inhibited by 6-hydroxynicotinic acid (6-HNA), the first metabolite of the NA degradative pathway. Reporter assays with the isogenic mutant derivative of the wild-type (WT) strain harboring deletion innicA, which encodes a putative nicotinic acid hydroxylase responsible for conversion of NA to 6-HNA, showed that 6-HNA is the actual inducer of thenicgenes in the bacterial cell. Gene expression profiling further showed that BpsR dually activated and repressed the expression of genes associated with pathogenesis, transcriptional regulation, metabolism, and other cellular processes. We discuss the implications of these findings with respect to the selection of pyridines such as NA and quinolinic acid for optimum bacterial growth depending on the ecological niche.IMPORTANCEBpsR, the previously described regulator of biofilm formation and Bps polysaccharide production, controlsBordetella bronchisepticagrowth by regulating the expression of genes involved in the degradation of nicotinic acid (NA). 6-Hydroxynicotinic acid (6-HNA), the first metabolite of the NA degradation pathway prevented BpsR from binding to DNA and was the actualin vivoinducer. We hypothesize that BpsR enablesBordetellabacteria to efficiently and selectively utilize NA for their survival depending on the environment in which they reside. The results reported herein lay the foundation for future investigations of how BpsR and the alteration of its activity by NA orchestrate the control ofBordetellagrowth, metabolism, biofilm formation, and pathogenesis.

scholarly journals Regulator RcsB Controls Prodigiosin Synthesis and Various Cellular Processes in Serratia marcescens JNB5-1

2020 ◽  
Vol 87 (2) ◽  
Author(s):  
Xuewei Pan ◽  
Mi Tang ◽  
Jiajia You ◽  
Fei Liu ◽  
Changhao Sun ◽  
...  
Keyword(s):  
Cell Motility ◽  
Serratia Marcescens ◽  
Biofilm Formation ◽  
Capsular Polysaccharide ◽  
Regulatory Mechanism ◽  
Acid Resistance ◽  
Content Type ◽  
Cellular Processes ◽  
Polysaccharide Production ◽  
Insight Into

ABSTRACT Prodigiosin (PG), a red linear tripyrrole pigment normally secreted by Serratia marcescens, has received attention for its reported immunosuppressive, antimicrobial, and anticancer properties. Although several genes have been shown to be important for prodigiosin synthesis, information on the regulatory mechanisms behind this cellular process remains limited. In this work, we identified that the transcriptional regulator RcsB encoding gene BVG90_13250 (rcsB) negatively controlled prodigiosin biosynthesis in S. marcescens. Disruption of rcsB conferred a remarkably increased production of prodigiosin. This phenotype corresponded to negative control of transcription of the prodigiosin-associated pig operon by RcsB, probably by binding to the promoter region of the prodigiosin synthesis positive regulator FlhDC. Moreover, using transcriptomics and further experiments, we revealed that RcsB also controlled some other important cellular processes, including swimming and swarming motilities, capsular polysaccharide production, biofilm formation, and acid resistance (AR), in S. marcescens. Collectively, this work proposes that RcsB is a prodigiosin synthesis repressor in S. marcescens and provides insight into the regulatory mechanism of RcsB in cell motility, capsular polysaccharide production, and acid resistance in S. marcescens. IMPORTANCE RcsB is a two-component response regulator in the Rcs phosphorelay system, and it plays versatile regulatory functions in Enterobacteriaceae. However, information on the function of the RcsB protein in bacteria, especially in S. marcescens, remains limited. In this work, we illustrated experimentally that the RcsB protein was involved in diverse cellular processes in S. marcescens, including prodigiosin synthesis, cell motility, capsular polysaccharide production, biofilm formation, and acid resistance. Additionally, the regulatory mechanism of the RcsB protein in these cellular processes was investigated. In conclusion, this work indicated that RcsB could be a regulator for prodigiosin synthesis and provides insight into the function of the RcsB protein in S. marcescens.

scholarly journals Common dyes used to determine bacterial polysaccharides on agar are affected by medium acidification

2017 ◽  
Vol 63 (6) ◽  
pp. 559-562 ◽  
Author(s):  
Justin P. Hawkins ◽  
Barney A. Geddes ◽  
Ivan J. Oresnik
Keyword(s):  
Mutant Strain ◽  
Growth Medium ◽  
Congo Red ◽  
Sinorhizobium Meliloti ◽  
Aniline Blue ◽  
Wild Type ◽  
Calcofluor White ◽  
Medium Acidification ◽  
Polysaccharide Production ◽  
Effects Of Ph

In this work, we highlight effects of pH on bacterial phenotypes when using the bacteriological dyes Aniline blue, Congo red, and Calcofluor white to analyze polysaccharide production. A study of galactose catabolism in Sinorhizobium meliloti led to the isolation of a mutation in dgoK1, which was observed to overproduce exopolysaccharides when grown in the presence of galactose. When this mutant strain was spotted onto plates containing Aniline blue, Congo red, or Calcofluor white, the intensity of the associated staining was strikingly different from that of the wild type. Additionally, a Calcofluor dull phenotype was observed, suggesting production of a polysaccharide other than succinoglycan. Further investigation of this phenotype revealed that these results were dependent on medium acidification, as buffering at pH 6 had no effect on these phenotypes, while medium buffered at pH 6.5 resulted in a reversal of the phenotypes. Screening for mutants of the dgoK1 strain that were negative for the Aniline blue phenotype yielded a strain carrying a mutation in tkt2, which is annotated as a putative transketolase. Consistent with the plate phenotypes, when this mutant was grown in broth cultures, it did not acidify its growth medium. Overall, this work shows that caution should be exercised in evaluating polysaccharide phenotypes based strictly on the use of dyes.

scholarly journals Influence of sub-inhibitory concentrations of antimicrobials on micrococcal nuclease and biofilm formation in Staphylococcus aureus

2020 ◽  
Author(s):  
Jelmer Sjollema ◽  
Henny van der Mei ◽  
Colin Rosman
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Extracellular Dna ◽  
Micrococcal Nuclease ◽  
Major Contributor ◽  
Polysaccharide Production ◽  
Minimum Inhibitory Concentrations ◽  
The Impact

Abstract A major contributor to biomaterial associated infection (BAI) is Staphylococcus aureus. This pathogen produces a protective biofilm, making eradication difficult. Biofilms are composed of bacteria encapsulated in a matrix of extracellular polymeric substances (EPS) comprising polysaccharides, proteins and extracellular DNA (eDNA). S. aureus also produces micrococcal nuclease (MN), an endonuclease which contributes to biofilm composition and dispersion, mainly expressed by nuc1. MN expression can be modulated by sub-minimum inhibitory concentrations of antimicrobials. We investigated the relation between the biofilm and MN expression and the impact of the application of antimicrobial pressure on this relation. Planktonic and biofilm cultures of three S. aureus strains, including a nuc1 deficient strain, were cultured under antimicrobial pressure. Results indicated that nuc1 deletion stimulates the polysaccharide production per CFU in the biofilm in in vitro biofilms. Also antimicrobial pressure of ciproflocacin, doxycycline and erythromycin resulted in significantly increased quantities of polysaccharides per CFU, but this did only coincide with significantly reduced MN activity in erythromycin. Resveratrol significantly reduced MN production per CFU but did not affect polysaccharides production. In conclusion, various antimicrobials impact the balance of eDNA, polysaccharides and MN production, all in a different way.

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