Promoting Beneficial and Inhibiting Undesirable Biofilm Formation with Mangrove Extracts.

Glasenapp Glasenapp,Cattò Cattò,Villa Villa,Saracchi Saracchi,Cappitelli Cappitelli,Papenbrock Papenbrock

doi:10.3390/ijms20143549

Abstract

The extracts of two mangrove species, Bruguiera cylindrica and Laguncularia racemosa, have been analyzed at sub-lethal concentrations for their potential to modulate biofilm cycles (i.e., adhesion, maturation, and detachment) on a bacterium, yeast, and filamentous fungus. Methanolic leaf extracts were also characterized, and MS/MS analysis has been used to identify the major compounds. In this study, we showed the following. (i) Adhesion was reduced up to 85.4% in all the models except for E. coli, where adhesion was promoted up to 5.10-fold. (ii) Both the sum and ratio of extracellular polysaccharides and proteins in mature biofilm were increased up to 2.5-fold and 2.6-fold in comparison to the negative control, respectively. Additionally, a shift toward a major production of exopolysaccharides was found coupled with a major production of both intracellular and extracellular reactive oxygen species. (iii) Lastly, detachment was generally promoted. In general, the L. racemosa extract had a higher bioactivity at lower concentrations than the B. cylindrica extract. Overall, our data showed a reduction in cells/conidia adhesion under B. cylindrica and L. racemosa exposure, followed by an increase of exopolysaccharides during biofilm maturation and a variable effect on biofilm dispersal. In conclusion, extracts either inhibited or enhanced biofilm development, and this effect depended on both the microbial taxon and biofilm formation step.

Highlights

Microorganisms, including fungi, adhere to surfaces and form complex and heterogeneous microbial communities called biofilms
LCCr-uMdSe Amneathlyasnisoolf(SMeceotnOdHar)yeMxtertaacbtosliotfesB. cylindrica and L. racemosa leaves were further analyzed for thCerirusdeecomnedtharaynoml e(MtabetoOliHte)ceoxmtrpacotssitoiof nB.bcyylLinCd-rMicaS a(TnadbLle. r1acaenmdosFaigleuarveeSs1w). eMreafsusrsthigenraalnsailnyztheed rfaonrgteheoifr1s0e0cotond8a0r0yDma eintaEbSoIlistehocwomedpovsairtyioingbsyigLnCa-lsMfSor(Tboabthlesp1eacnieds.FMigSuraenSd1M)
We proved that each new compound or extract needs to be investigated, taking into account the multiple steps of biofilm formation, in order to assess its real behavior in the environment

Summary

Introduction

Microorganisms, including fungi, adhere to surfaces and form complex and heterogeneous microbial communities called biofilms. The employment of biofilms in other environments, such as for bioremediation, in wastewater treatment plants [7,8], in other industrial settings [9], and for microbial fuel cells [10] is remarkably beneficial In the former case, research has aimed at preventing adhesion, reducing maturation, and favoring detachment. The enhancement of initial adhesion to a substratum and the subsequent formation of robust mature biofilms are important goals to achieve Despite their beneficial roles in many fields, biofilms are mainly associated with negative impacts. In this direction, antimicrobial agents aimed at killing microorganisms have been extensively employed to control biofilm growth. Agents promoting biofilm development have been less investigated [14]

Methods

Results

Conclusion