Journal articles on the topic 'Biofilms marins'
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1
Sousa-Cardoso, Francisca, Rita Teixeira-Santos, Ana Francisca Campos, Marta Lima, Luciana C. Gomes, Olívia S. G. P. Soares, and Filipe J. Mergulhão. "Graphene-Based Coating to Mitigate Biofilm Development in Marine Environments." Nanomaterials 13, no. 3 (January 18, 2023): 381. http://dx.doi.org/10.3390/nano13030381.
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Due to its several economic and ecological consequences, biofouling is a widely recognized concern in the marine sector. The search for non-biocide-release antifouling coatings has been on the rise, with carbon-nanocoated surfaces showing promising activity. This work aimed to study the impact of pristine graphene nanoplatelets (GNP) on biofilm development through the representative marine bacteria Cobetia marina and to investigate the antibacterial mechanisms of action of this material. For this purpose, a flow cytometric analysis was performed and a GNP/polydimethylsiloxane (PDMS) surface containing 5 wt% GNP (G5/PDMS) was produced, characterized, and assessed regarding its biofilm mitigation potential over 42 days in controlled hydrodynamic conditions that mimic marine environments. Flow cytometry revealed membrane damage, greater metabolic activity, and endogenous reactive oxygen species (ROS) production by C. marina when exposed to GNP 5% (w/v) for 24 h. In addition, C. marina biofilms formed on G5/PDMS showed consistently lower cell count and thickness (up to 43% reductions) than PDMS. Biofilm architecture analysis indicated that mature biofilms developed on the graphene-based surface had fewer empty spaces (34% reduction) and reduced biovolume (25% reduction) compared to PDMS. Overall, the GNP-based surface inhibited C. marina biofilm development, showing promising potential as a marine antifouling coating.
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Liang, Xiao, Xiu-Kun Zhang, Li-Hua Peng, You-Ting Zhu, Asami Yoshida, Kiyoshi Osatomi, and Jin-Long Yang. "The Flagellar Gene Regulates Biofilm Formation and Mussel Larval Settlement and Metamorphosis." International Journal of Molecular Sciences 21, no. 3 (January 21, 2020): 710. http://dx.doi.org/10.3390/ijms21030710.
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Biofilms are critical components of most marine systems and provide biochemical cues that can significantly impact overall community composition. Although progress has been made in the bacteria–animal interaction, the molecular basis of modulation of settlement and metamorphosis in most marine animals by bacteria is poorly understood. Here, Pseudoalteromonas marina showing inducing activity on mussel settlement and metamorphosis was chosen as a model to clarify the mechanism that regulates the bacteria–mussel interaction. We constructed a flagellin synthetic protein gene fliP deletion mutant of P. marina and checked whether deficiency of fliP gene will impact inducing activity, motility, and extracellular polymeric substances of biofilms. Furthermore, we examined the effect of flagellar proteins extracted from bacteria on larval settlement and metamorphosis. The deletion of the fliP gene caused the loss of the flagella structure and motility of the ΔfliP strain. Deficiency of the fliP gene promoted the biofilm formation and changed biofilm matrix by reducing β-polysaccharides and increasing extracellular proteins and finally reduced biofilm-inducing activities. Flagellar protein extract promoted mussel metamorphosis, and ΔfliP biofilms combined with additional flagellar proteins induced similar settlement and metamorphosis rate compared to that of the wild-type strain. These findings provide novel insight on the molecular interactions between bacteria and mussels.
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Long, Lexin, Ruojun Wang, Ho Yin Chiang, Wei Ding, Yong-Xin Li, Feng Chen, and Pei-Yuan Qian. "Discovery of Antibiofilm Activity of Elasnin against Marine Biofilms and Its Application in the Marine Antifouling Coatings." Marine Drugs 19, no. 1 (January 5, 2021): 19. http://dx.doi.org/10.3390/md19010019.
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Biofilms are surface-attached multicellular communities that play critical roles in inducing biofouling and biocorrosion in the marine environment. Given the serious economic losses and problems caused by biofouling and biocorrosion, effective biofilm control strategies are highly sought after. In a screening program of antibiofilm compounds against marine biofilms, we discovered the potent biofilm inhibitory activity of elasnin. Elasnin effectively inhibited the biofilm formation of seven strains of bacteria isolated from marine biofilms. With high productivity, elasnin-based coatings were prepared in an easy and cost-effective way, which exhibited great performance in inhibiting the formation of multi-species biofilms and the attachment of large biofouling organisms in the marine environment. The 16S amplicon analysis and anti-larvae assay revealed that elasnin could prevent biofouling by the indirect impact of changed microbial composition of biofilms and direct inhibitory effect on larval settlement with low toxic effects. These findings indicated the potential application of elasnin in biofilm and biofouling control in the marine environment.
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Tuck, Benjamin, Silvia J. Salgar-Chaparro, Elizabeth Watkin, Anthony Somers, Maria Forsyth, and Laura L. Machuca. "Extracellular DNA: A Critical Aspect of Marine Biofilms." Microorganisms 10, no. 7 (June 24, 2022): 1285. http://dx.doi.org/10.3390/microorganisms10071285.
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Multispecies biofilms represent a pervasive threat to marine-based industry, resulting in USD billions in annual losses through biofouling and microbiologically influenced corrosion (MIC). Biocides, the primary line of defence against marine biofilms, now face efficacy and toxicity challenges as chemical tolerance by microorganisms increases. A lack of fundamental understanding of species and EPS composition in marine biofilms remains a bottleneck for the development of effective, target-specific biocides with lower environmental impact. In the present study, marine biofilms are developed on steel with three bacterial isolates to evaluate the composition of the EPSs (extracellular polymeric substances) and population dynamics. Confocal laser scanning microscopy, scanning electron microscopy, and fluorimetry revealed that extracellular DNA (eDNA) was a critical structural component of the biofilms. Parallel population analysis indicated that all three strains were active members of the biofilm community. However, eDNA composition did not correlate with strain abundance or activity. The results of the EPS composition analysis and population analysis reveal that biofilms in marine conditions can be stable, well-defined communities, with enabling populations that shape the EPSs. Under marine conditions, eDNA is a critical EPS component of the biofilm and represents a promising target for the enhancement of biocide specificity against these populations.
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Faria, Sara I., Rita Teixeira-Santos, Maria J. Romeu, João Morais, Vitor Vasconcelos, and Filipe J. Mergulhão. "The Relative Importance of Shear Forces and Surface Hydrophobicity on Biofilm Formation by Coccoid Cyanobacteria." Polymers 12, no. 3 (March 12, 2020): 653. http://dx.doi.org/10.3390/polym12030653.
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Understanding the conditions affecting cyanobacterial biofilm development is crucial to develop new antibiofouling strategies and decrease the economic and environmental impact of biofilms in marine settings. In this study, we investigated the relative importance of shear forces and surface hydrophobicity on biofilm development by two coccoid cyanobacteria with different biofilm formation capacities. The strong biofilm-forming Synechocystis salina was used along with the weaker biofilm-forming Cyanobium sp. Biofilms were developed in defined hydrodynamic conditions using glass (a model hydrophilic surface) and a polymeric epoxy coating (a hydrophobic surface) as substrates. Biofilms developed in both surfaces at lower shear conditions contained a higher number of cells and presented higher values for wet weight, thickness, and chlorophyll a content. The impact of hydrodynamics on biofilm development was generally stronger than the impact of surface hydrophobicity, but a combined effect of these two parameters strongly affected biofilm formation for the weaker biofilm-producing organism. The antibiofilm performance of the polymeric coating was confirmed at the hydrodynamic conditions prevailing in ports. Shear forces were shown to have a profound impact on biofilm development in marine settings regardless of the fouling capacity of the existing flora and the hydrophobicity of the surface.
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Dheilly, Alexandra, Emmanuelle Soum-Sout�ra, G�raldine L. Klein, Alexis Bazire, Chantal Comp�re, Dominique Haras, and Alain Dufour. "Antibiofilm Activity of the Marine Bacterium Pseudoalteromonas sp. Strain 3J6." Applied and Environmental Microbiology 76, no. 11 (April 2, 2010): 3452–61. http://dx.doi.org/10.1128/aem.02632-09.
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ABSTRACT Biofilm formation results in medical threats or economic losses and is therefore a major concern in a variety of domains. In two-species biofilms of marine bacteria grown under dynamic conditions, Pseudoalteromonas sp. strain 3J6 formed mixed biofilms with Bacillus sp. strain 4J6 but was largely predominant over Paracoccus sp. strain 4M6 and Vibrio sp. strain D01. The supernatant of Pseudoalteromonas sp. 3J6 liquid culture (SN3J6) was devoid of antibacterial activity against free-living Paracoccus sp. 4M6 and Vibrio sp. D01 cells, but it impaired their ability to grow as single-species biofilms and led to higher percentages of nonviable cells in 48-h biofilms. Antibiofilm molecules of SN3J6 were able to coat the glass surfaces used to grow biofilms and reduced bacterial attachment about 2-fold, which might partly explain the biofilm formation defect but not the loss of cell viability. SN3J6 had a wide spectrum of activity since it affected all Gram-negative marine strains tested except other Pseudoalteromonas strains. Biofilm biovolumes of the sensitive strains were reduced 3- to 530-fold, and the percentages of nonviable cells were increased 3- to 225-fold. Interestingly, SN3J6 also impaired biofilm formation by three strains belonging to the human-pathogenic species Pseudomonas aeruginosa, Salmonella enterica, and Escherichia coli. Such an antibiofilm activity is original and opens up a variety of applications for Pseudoalteromonas sp. 3J6 and/or its active exoproducts in biofilm prevention strategies.
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Mai-Prochnow, Anne, Flavia Evans, Doralyn Dalisay-Saludes, Sacha Stelzer, Suhelen Egan, Sally James, Jeremy S. Webb, and Staffan Kjelleberg. "Biofilm Development and Cell Death in the Marine Bacterium Pseudoalteromonas tunicata." Applied and Environmental Microbiology 70, no. 6 (June 2004): 3232–38. http://dx.doi.org/10.1128/aem.70.6.3232-3238.2004.
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ABSTRACT The newly described green-pigmented bacterium Pseudoalteromonas tunicata (D2) produces target-specific inhibitory compounds against bacteria, algae, fungi, and invertebrate larvae and is frequently found in association with living surfaces in the marine environment. As part of our studies on the ecology of P. tunicata and its interaction with marine surfaces, we examined the ability of P. tunicata to form biofilms under continuous culture conditions within the laboratory. P. tunicata biofilms exhibited a characteristic architecture consisting of differentiated microcolonies surrounded by water channels. Remarkably, we observed a repeatable pattern of cell death during biofilm development of P. tunicata, similar to that recently reported for biofilms of Pseudomonas aeruginosa (J. S. Webb et al., J. Bacteriol. 185:4585-4595, 2003). Killing and lysis occurred inside microcolonies, apparently resulting in the formation of voids within these structures. A subpopulation of viable cells was always observed within the regions of killing in the biofilm. Moreover, extensive killing in mature biofilms appeared to result in detachment of the biofilm from the substratum. A novel 190-kDa autotoxic protein produced by P. tunicata, designated AlpP, was found to be involved in this biofilm killing and detachment. A ΔalpP mutant derivative of P. tunicata was generated, and this mutant did not show cell death during biofilm development. We propose that AlpP-mediated cell death plays an important role in the multicellular biofilm development of P. tunicata and subsequent dispersal of surviving cells within the marine environment.
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Gill, Stephanie P., Louise Kregting, Ibrahim M. Banat, Joerg Arnscheidt, and William R. Hunter. "Rhamnolipids Mediate the Effects of a Gastropod Grazer in Regards to Carbon–Nitrogen Stoichiometry of Intertidal Microbial Biofilms." Applied Sciences 12, no. 24 (December 12, 2022): 12729. http://dx.doi.org/10.3390/app122412729.
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Microbial biofilms have co-evolved with grazing animals, such as gastropods, to develop mutually beneficial relationships. Although microbial biofilms demonstrate resilience and resistance to chemical exposure, pre-existing relationships can be negatively affected by chemical input. In this study, we determined how the grazer, Littorina littorea (common periwinkle sea snail), and a biological surfactant (rhamnolipid) interact on a phototrophic marine biofilm. Biofilms were cultured in 32 twenty-liter buckets at the Queen’s University Marine Laboratory in Portaferry, Northern Ireland on clay tiles that were either exposed to 150 ppm of a rhamnolipid solution or that had no chemical exposure. L. littorea were added into half of the buckets, and biofilms were developed over 14 days. Biofilms exposed to grazing alone demonstrated high tolerance to the disturbance, while those growing on rhamnolipid-exposed substrate demonstrated resistance but experienced slight declines in carbon and stoichiometric ratios. However, when exposed to both, biofilms had significant decreases in stoichiometry and declined in productivity and respiration. This is problematic, as continuing marine pollution increases the likelihood that biofilms will be exposed to combinations of stressors and disturbances. Loss of biofilm productivity within these areas could lead to the loss of an important food source and nutrient cycler within the marine ecosystem.
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Faria, Sara I., Rita Teixeira-Santos, Maria J. Romeu, João Morais, Ed de Jong, Jelmer Sjollema, Vítor Vasconcelos, and Filipe J. Mergulhão. "Unveiling the Antifouling Performance of Different Marine Surfaces and Their Effect on the Development and Structure of Cyanobacterial Biofilms." Microorganisms 9, no. 5 (May 20, 2021): 1102. http://dx.doi.org/10.3390/microorganisms9051102.
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Since biofilm formation by microfoulers significantly contributes to the fouling process, it is important to evaluate the performance of marine surfaces to prevent biofilm formation, as well as understand their interactions with microfoulers and how these affect biofilm development and structure. In this study, the long-term performance of five surface materials—glass, perspex, polystyrene, epoxy-coated glass, and a silicone hydrogel coating—in inhibiting biofilm formation by cyanobacteria was evaluated. For this purpose, cyanobacterial biofilms were developed under controlled hydrodynamic conditions typically found in marine environments, and the biofilm cell number, wet weight, chlorophyll a content, and biofilm thickness and structure were assessed after 49 days. In order to obtain more insight into the effect of surface properties on biofilm formation, they were characterized concerning their hydrophobicity and roughness. Results demonstrated that silicone hydrogel surfaces were effective in inhibiting cyanobacterial biofilm formation. In fact, biofilms formed on these surfaces showed a lower number of biofilm cells, chlorophyll a content, biofilm thickness, and percentage and size of biofilm empty spaces compared to remaining surfaces. Additionally, our results demonstrated that the surface properties, together with the features of the fouling microorganisms, have a considerable impact on marine biofouling potential.
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Dusane, D. H., Y. V. Nancharaiah, V. P. Venugopalan, A. R. Kumar, and S. S. Zinjarde. "Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589." Water Science and Technology 58, no. 6 (October 1, 2008): 1221–29. http://dx.doi.org/10.2166/wst.2008.479.
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Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.
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Dusane, D. H., Y. V. Nancharaiah, V. P. Venugopalan, A. R. Kumar, and S. S. Zinjarde. "Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589." Water Science and Technology 58, no. 12 (December 1, 2008): 2467–75. http://dx.doi.org/10.2166/wst.2008.585.
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Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.
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Mugge, Rachel L., Rachel D. Moseley, and Leila J. Hamdan. "Substrate Specificity of Biofilms Proximate to Historic Shipwrecks." Microorganisms 11, no. 10 (September 27, 2023): 2416. http://dx.doi.org/10.3390/microorganisms11102416.
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The number of built structures on the seabed, such as shipwrecks, energy platforms, and pipelines, is increasing in coastal and offshore regions. These structures, typically composed of steel or wood, are substrates for microbial attachment and biofilm formation. The success of biofilm growth depends on substrate characteristics and local environmental conditions, though it is unclear which feature is dominant in shaping biofilm microbiomes. The goal of this study was to understand the substrate- and site-specific impacts of built structures on short-term biofilm composition and functional potential. Seafloor experiments were conducted wherein steel and wood surfaces were deployed for four months at distances extending up to 115 m away from three historic (>50 years old) shipwrecks in the Gulf of Mexico. DNA from biofilms on the steel and wood was extracted, and metagenomes were sequenced on an Illumina NextSeq. A bioinformatics analysis revealed that the taxonomic composition was significantly different between substrates and sites, with substrate being the primary determining factor. Regardless of site, the steel biofilms had a higher abundance of genes related to biofilm formation, and sulfur, iron, and nitrogen cycling, while the wood biofilms showed a higher abundance of manganese cycling and methanol oxidation genes. This study demonstrates how substrate composition shapes biofilm microbiomes and suggests that marine biofilms may contribute to nutrient cycling at depth. Analyzing the marine biofilm microbiome provides insight into the ecological impact of anthropogenic structures on the seabed.
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Cacabelos, Eva, Patrício Ramalhosa, João Canning-Clode, Jesús S. Troncoso, Celia Olabarria, Cristina Delgado, Sergey Dobretsov, and Ignacio Gestoso. "The Role of Biofilms Developed under Different Anthropogenic Pressure on Recruitment of Macro-Invertebrates." International Journal of Molecular Sciences 21, no. 6 (March 16, 2020): 2030. http://dx.doi.org/10.3390/ijms21062030.
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Microbial biofilms can be key mediators for settlement of macrofoulers. The present study examines the coupled effects of microbial biofilms and local environmental conditions on the composition, structure and functioning of macrofouling assemblages. Settlement of invertebrates over a gradient of human-impacted sites was investigated on local biofilms and on biofilms developed in marine protected areas (MPAs). Special attention was given to the presence of non-indigenous species (NIS), a global problem that can cause important impacts on local assemblages. In general, the formation of macrofouling assemblages was influenced by the identity of the biofilm. However, these relationships varied across levels of anthropogenic pressure, possibly influenced by environmental conditions and the propagule pressure locally available. While the NIS Watersipora subatra seemed to be inhibited by the biofilm developed in the MPA, Diplosoma cf. listerianum seemed to be attracted by biofilm developed in the MPA only under mid anthropogenic pressure. The obtained information is critical for marine environmental management, urgently needed for the establishment of prevention and control mechanisms to minimize the settlement of NIS and mitigate their threats.
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Faria, Sara I., Rita Teixeira-Santos, Luciana C. Gomes, Elisabete R. Silva, João Morais, Vítor Vasconcelos, and Filipe J. M. Mergulhão. "Experimental Assessment of the Performance of Two Marine Coatings to Curb Biofilm Formation of Microfoulers." Coatings 10, no. 9 (September 18, 2020): 893. http://dx.doi.org/10.3390/coatings10090893.
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Biofilms formed on submerged marine surfaces play a critical role in the fouling process, causing increased fuel consumption, corrosion, and high maintenance costs. Thus, marine biofouling is a major issue and motivates the development of antifouling coatings. In this study, the performance of two commercial marine coatings, a foul-release silicone-based paint (SilRef) and an epoxy resin (EpoRef), was evaluated regarding their abilities to prevent biofilm formation by Cyanobium sp. and Pseudoalteromonas tunicata (common microfoulers). Biofilms were developed under defined hydrodynamic conditions to simulate marine settings, and the number of biofilm cells, wet weight, and thickness were monitored for 7 weeks. The biofilm structure was analyzed by confocal laser scanning microscopy (CLSM) at the end-point. Results demonstrated that EpoRef surfaces were effective in inhibiting biofilm formation at initial stages (until day 28), while SilRef surfaces showed high efficacy in decreasing biofilm formation during maturation (from day 35 onwards). Wet weight and thickness analysis, as well as CLSM data, indicate that SilRef surfaces were less prone to biofilm formation than EpoRef surfaces. Furthermore, the efficacy of SilRef surfaces may be dependent on the fouling microorganism, while the performance of EpoRef was strongly influenced by a combined effect of surface and microorganism.
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Faria, Sara I., Luciana C. Gomes, Rita Teixeira-Santos, João Morais, Vítor Vasconcelos, and Filipe J. M. Mergulhão. "Developing New Marine Antifouling Surfaces: Learning from Single-Strain Laboratory Tests." Coatings 11, no. 1 (January 15, 2021): 90. http://dx.doi.org/10.3390/coatings11010090.
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The development of antifouling (AF) technology for marine environments is an area of intense research given the severe economic and ecological effects of marine biofouling. Preliminary data from in vitro assays is frequently used to screen the performance of AF coatings. It is intuitive that microbial composition plays a major role in surface colonization. The rationale behind this study is to investigate whether using a mixed population for the in vitro tests yields substantially different results than using single strains during initial screening. A polymeric coating was tested against single- and dual-species cultures of two common microfouler organisms for 49 days. A bacterium (Pseudoaltermonas tunicata) and a cyanobacterium (Cyanobium sp. LEGE 10375) were used in this study. Linear regression analysis revealed that Cyanobium sp. biofilms were significantly associated with a higher number of cells, wet weight, thickness, and biovolume compared to dual-species biofilms. P. tunicata alone had a biofilm growth kinetics similar to dual-species biofilms, although the P. tunicata–Cyanobium sp. mixture developed less dense and thinner biofilms compared to both single-species biofilms. Cyanobium sp. LEGE 10375 biofilms provided the worst-case scenario, i.e., the conditions that caused higher biofilm amounts on the surface material under test. Therefore, it is likely that assessing the AF performance of new coatings using the most stringent conditions may yield more robust results than using a mixed population, as competition between microfouler organisms may reduce the biofilm formation capacity of the consortium.
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Doghri, Ibtissem, Emilie Portier, Florie Desriac, Jean Michel Zhao, Alexis Bazire, Alain Dufour, Vincent Rochette, Sophie Sablé, and Isabelle Lanneluc. "Anti-Biofilm Activity of a Low Weight Proteinaceous Molecule from the Marine Bacterium Pseudoalteromonas sp. IIIA004 against Marine Bacteria and Human Pathogen Biofilms." Microorganisms 8, no. 9 (August 25, 2020): 1295. http://dx.doi.org/10.3390/microorganisms8091295.
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Pseudoalteromonas bacteria are known as potential bioactive metabolite producers. Because of the need to obtain natural molecules inhibiting the bacterial biofilms, we investigated the biofilm inhibitory activity of the marine bacterium Pseudoalteromonas sp. IIIA004 against the pioneer surface colonizer Roseovarius sp. VA014. The anti-biofilm activity from the culture supernatant of Pseudoalteromonas sp. IIIA004 (SNIIIA004) was characterized in microtiter plates (static conditions/polystyrene surface) and in flow cell chambers (dynamic conditions/glass surface). The Pseudoalteromonas exoproducts exhibited an inhibition of Roseovarius sp. VA014 biofilm formation as well as a strong biofilm dispersion, without affecting the bacterial growth. Microbial adhesion to solvent assays showed that SNIIIA004 did not change the broad hydrophilic and acid character of the Roseovarius strain surface. Bioassay-guided purification using solid-phase extraction and C18 reverse-phase-high-performance liquid chromatography (RP-HPLC) was performed from SNIIIA004 to isolate the proteinaceous active compound against the biofilm formation. This new anti-biofilm low weight molecule (< 3kDa), named P004, presented a wide spectrum of action on various bacterial biofilms, with 71% of sensitive strains including marine bacteria and human pathogens. Pseudoalteromonas sp. IIIA004 is a promising source of natural anti-biofilm compounds that combine several activities.
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Tuck, Benjamin, Elizabeth Watkin, Anthony Somers, Maria Forsyth, and Laura L. Machuca. "Enhancing Biocide Efficacy: Targeting Extracellular DNA for Marine Biofilm Disruption." Microorganisms 10, no. 6 (June 15, 2022): 1227. http://dx.doi.org/10.3390/microorganisms10061227.
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Biofilm formation is a global health, safety and economic concern. The extracellular composition of deleterious multispecies biofilms remains uncanvassed, leading to an absence of targeted biofilm mitigation strategies. Besides economic incentives, drive also exists from industry and research to develop and apply environmentally sustainable chemical treatments (biocides); especially in engineered systems associated with the marine environment. Recently, extracellular DNA (eDNA) was implicated as a critical structural polymer in marine biofilms. Additionally, an environmentally sustainable, multi-functional biocide was also introduced to manage corrosion and biofilm formation. To anticipate biofilm tolerance acquisition to chemical treatments and reduce biocide application quantities, the present research investigated eDNA as a target for biofilm dispersal and potential enhancement of biocide function. Results indicate that mature biofilm viability can be reduced by two-fold using reduced concentrations of the biocide alone (1 mM instead of the recommended 10 mM). Importantly, through the incorporation of an eDNA degradation stage, biocide function could be enhanced by a further ~90% (one further log reduction in viability). Biofilm architecture analysis post-treatment revealed that endonuclease targeting of the matrix allowed greater biocide penetration, leading to the observed viability reduction. Biofilm matrix eDNA is a promising target for biofilm dispersal and antimicrobial enhancement in clinical and engineered systems.
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Staal, M., R. Thar, M. Kühl, M. C. M. van Loosdrecht, G. Wolf, J. F. C. de Brouwer, and J. W. Rijstenbil. "Different carbon isotope fractionation patterns during the development of phototrophic freshwater and marine biofilms." Biogeosciences 4, no. 4 (August 8, 2007): 613–26. http://dx.doi.org/10.5194/bg-4-613-2007.
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Abstract. Natural phototrophic biofilms are influenced by a broad array of abiotic and biotic factors and vary over temporal and spatial scales. Different developmental stages can be distinguished and growth rates will vary due to the thickening of the biofilm, which is expected to lead to a limitation of light or mass transport. This study shows that variation in CO2(aq) availability leads to a fractionation shift and thereby affects δ13C signatures during biofilm development. For phototrophic freshwater biofilms it was found that the δ13C value became less negative with the thickening of the biofilm, while the opposite trend was found in marine biofilms. Modeling and pH profiling indicated that the trend in the freshwater system was caused by an increase in CO2(aq) limitation resulting in an increase of HCO3− as C-source. The opposite trend in the marine system could be explained by a higher heterotrophic biomass and activity causing a higher carbon recycling and thereby lower δ13C values. We conclude that δ13C was more related to the net areal photosynthesis rate and carbon recycling, rather than to the growth rate of the biofilms.
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Burm�lle, Mette, Jeremy S. Webb, Dhana Rao, Lars H. Hansen, S�ren J. S�rensen, and Staffan Kjelleberg. "Enhanced Biofilm Formation and Increased Resistance to Antimicrobial Agents and Bacterial Invasion Are Caused by Synergistic Interactions in Multispecies Biofilms." Applied and Environmental Microbiology 72, no. 6 (June 2006): 3916–23. http://dx.doi.org/10.1128/aem.03022-05.
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ABSTRACT Most biofilms in their natural environments are likely to consist of consortia of species that influence each other in synergistic and antagonistic manners. However, few reports specifically address interactions within multispecies biofilms. In this study, 17 epiphytic bacterial strains, isolated from the surface of the marine alga Ulva australis, were screened for synergistic interactions within biofilms when present together in different combinations. Four isolates, Microbacterium phyllosphaerae, Shewanella japonica, Dokdonia donghaensis, and Acinetobacter lwoffii, were found to interact synergistically in biofilms formed in 96-well microtiter plates: biofilm biomass was observed to increase by >167% in biofilms formed by the four strains compared to biofilms composed of single strains. When exposed to the antibacterial agent hydrogen peroxide or tetracycline, the relative activity (exposed versus nonexposed biofilms) of the four-species biofilm was markedly higher than that in any of the single-species biofilms. Moreover, in biofilms established on glass surfaces in flow cells and subjected to invasion by the antibacterial protein-producing Pseudoalteromonas tunicata, the four-species biofilms resisted invasion to a greater extent than did the biofilms formed by the single species. Replacement of each strain by its cell-free culture supernatant suggested that synergy was dependent both on species-specific physical interactions between cells and on extracellular secreted factors or less specific interactions. In summary, our data strongly indicate that synergistic effects promote biofilm biomass and resistance of the biofilm to antimicrobial agents and bacterial invasion in multispecies biofilms.
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Levy, Jacqueline L., Jenny L. Stauber, Steven A. Wakelin, and Dianne F. Jolley. "The effect of field-collected biofilms on the toxicity of copper to a marine microalga (Tetraselmis sp.) in laboratory bioassays." Marine and Freshwater Research 62, no. 12 (2011): 1362. http://dx.doi.org/10.1071/mf10313.
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Standard algal growth rate inhibition bioassays can lack environmental realism and may over- or underestimate metal bioavailability in natural systems. In aquatic environments, algal species interact with other biota, including other algae, bacteria and biofilms. In this work, the feasibility of incorporating marine biofilms into 72 h algal growth inhibition toxicity tests was explored. The effects of copper on Tetraselmis sp. were tested in the absence and presence of characterised field-collected biofilms. We hypothesised that the addition of biofilm would prevent copper toxicity to the alga primarily through interactions of the metal with other cells and biofilm exudates. The sensitivity of Tetraselmis sp. to copper (based on 72 h IC50 values; the copper concentration to inhibit population growth by 50%) in the presence of a blended biofilm inoculum varied 2-fold and was independent of the amount of biofilm added. However, increases in IC10 and IC20 values indicated some amelioration of copper toxicity. When intact biofilms were added to the bioassays, amelioration of toxicity was more consistent, probably due to increased binding of copper to cell surfaces or exudates. Difficulties in characterising biofilms and distinguishing that material from the test alga need to be overcome before biofilms can be routinely incorporated into laboratory bioassays.
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Nithya Deva Krupa, A., and Vimala Raghavan. "Biosynthesis of Silver Nanoparticles UsingAegle marmelos(Bael) Fruit Extract and Its Application to Prevent Adhesion of Bacteria: A Strategy to Control Microfouling." Bioinorganic Chemistry and Applications 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/949538.
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Marine biofilms formed due to adhesion of bacteria and other microorganisms on submerged surfaces are generally considered to be a major form of microfouling. Subsequent attachment of larvae of higher organisms like barnacles, mussels, and so forth, on marine biofilms, causes macrofouling. Several approaches have been used to prevent micro- and macrofouling. Silver nanoparticles (AgNPs) are known to exhibit strong inhibitory and antimicrobial activity. Biological synthesis of AgNPs is rapidly gaining importance due to its growing success. Hence, the present study is focused on the biosynthesis of AgNPs using fruit extract ofAegle marmelosand its characterization through UV-Vis spectrophotometer, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). Further isolation and identification of marine biofilm forming bacteria were carried out through 16S rDNA analysis. The antimicrofouling effect of the biosynthesized AgNPs was tested against marine biofilm forming bacteria and the results suggested that it could effectively inhibit biofilm formation. This preliminary study has proved that AgNPs may be used as antimicrofouling agent for the prevention of biofouling in the early stages.
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Rao, Dhana, Jeremy S. Webb, and Staffan Kjelleberg. "Competitive Interactions in Mixed-Species Biofilms Containing the Marine Bacterium Pseudoalteromonas tunicata." Applied and Environmental Microbiology 71, no. 4 (April 2005): 1729–36. http://dx.doi.org/10.1128/aem.71.4.1729-1736.2005.
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ABSTRACT Pseudoalteromonas tunicata is a biofilm-forming marine bacterium that is often found in association with the surface of eukaryotic organisms. It produces a range of extracellular inhibitory compounds, including an antibacterial protein (AlpP) thought to be beneficial for P. tunicata during competition for space and nutrients on surfaces. As part of our studies on the interactions between P. tunicata and the epiphytic bacterial community on the marine plant Ulva lactuca, we investigated the hypothesis that P. tunicata is a superior competitor compared with other bacteria isolated from the plant. A number of U. lactuca bacterial isolates were (i) identified by 16S rRNA gene sequencing, (ii) characterized for the production of or sensitivity to extracellular antibacterial proteins, and (iii) labeled with a fluorescent color tag (either the red fluorescent protein DsRed or green fluorescent protein). We then grew single- and mixed-species bacterial biofilms containing P. tunicata in glass flow cell reactors. In pure culture, all the marine isolates formed biofilms containing microcolony structures within 72 h. However, in mixed-species biofilms, P. tunicata removed the competing strain unless its competitor was relatively insensitive to AlpP (Pseudoalteromonas gracilis) or produced strong inhibitory activity against P. tunicata (Roseobacter gallaeciensis). Moreover, biofilm studies conducted with an AlpP− mutant of P. tunicata indicated that the mutant was less competitive when it was introduced into preestablished biofilms, suggesting that AlpP has a role during competitive biofilm formation. When single-species biofilms were allowed to form microcolonies before the introduction of a competitor, these microcolonies coexisted with P. tunicata for extended periods of time before they were removed. Two marine bacteria (R. gallaeciensis and P. tunicata) were superior competitors in this study. Our data suggest that this dominance can be attributed to the ability of these organisms to rapidly form microcolonies and their ability to produce extracellular antibacterial compounds.
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Mudrak, Benjamin, and Rita Tamayo. "The Vibrio cholerae Pst2 Phosphate Transport System Is Upregulated in Biofilms and Contributes to Biofilm-Induced Hyperinfectivity." Infection and Immunity 80, no. 5 (February 21, 2012): 1794–802. http://dx.doi.org/10.1128/iai.06277-11.
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ABSTRACTVibrio choleraeis the causative agent of the deadly diarrheal disease cholera. As part of its life cycle,V. choleraepersists in marine environments, where it forms surface-attached communities commonly described as biofilms. Evidence indicates that these biofilms constitute the infectious form of the pathogen during outbreaks. Previous work has shown that biofilm-derivedV. choleraecells, even when fully dispersed from the biofilm matrix, are vastly more infectious than planktonic (free-living) cells. Here, we sought to identify factors that contribute to biofilm-induced hyperinfectivity inV. cholerae, and we present evidence for one aspect of the molecular basis of this phenotype. We identified proteins upregulated during growth in biofilms and determined their contributions to the hyperinfectivity phenotype. We found that PstS2, the periplasmic component of the Pst2 phosphate uptake system, was enriched in biofilms. Another gene in thepst2locus was transcriptionally upregulated in biofilms. Using the infant mouse model, we found that mutation of twopst2components resulted in impaired colonization. Importantly, deletion of the Pst2 inner membrane complex caused a greater colonization defect after growth in a biofilm compared to shaking culture. Based on these data, we propose thatV. choleraecells in biofilms upregulate the Pst2 system and therefore gain an advantage upon entry into the host. Further characterization of factors contributing to biofilm-induced hyperinfectivity inV. choleraewill improve our understanding of the transmission of the bacteria from natural aquatic habitats to the human host.
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Wang, Kai-Ling, Zheng-Rong Dou, Gao-Fen Gong, Hai-Feng Li, Bei Jiang, and Ying Xu. "Anti-Larval and Anti-Algal Natural Products from Marine Microorganisms as Sources of Anti-Biofilm Agents." Marine Drugs 20, no. 2 (January 21, 2022): 90. http://dx.doi.org/10.3390/md20020090.
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Bacteria growing inside biofilms are more resistant to hostile environments, conventional antibiotics, and mechanical stresses than their planktonic counterparts. It is estimated that more than 80% of microbial infections in human patients are biofilm-based, and biofouling induced by the biofilms of some bacteria causes serious ecological and economic problems throughout the world. Therefore, exploring highly effective anti-biofilm compounds has become an urgent demand for the medical and marine industries. Marine microorganisms, a well-documented and prolific source of natural products, provide an array of structurally distinct secondary metabolites with diverse biological activities. However, up to date, only a handful of anti-biofilm natural products derived from marine microorganisms have been reported. Meanwhile, it is worth noting that some promising antifouling (AF) compounds from marine microbes, particularly those that inhibit settlement of fouling invertebrate larvae and algal spores, can be considered as potential anti-biofilm agents owing to the well-known knowledge of the correlations between biofilm formation and the biofouling process of fouling organisms. In this review, a total of 112 anti-biofilm, anti-larval, and anti-algal natural products from marine microbes and 26 of their synthetic analogues are highlighted from 2000 to 2021. These compounds are introduced based on their microbial origins, and then categorized into the following different structural groups: fatty acids, butenolides, terpenoids, steroids, phenols, phenyl ethers, polyketides, alkaloids, flavonoids, amines, nucleosides, and peptides. The preliminary structure-activity relationships (SAR) of some important compounds are also briefly discussed. Finally, current challenges and future research perspectives are proposed based on opinions from many previous reviews.
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Balsa-Canto, Eva, Alejandro López-Núñez, and Carlos Vázquez. "Numerical Simulation of the Dynamics of Listeria Monocytogenes Biofilms." Proceedings 2, no. 18 (September 18, 2018): 1182. http://dx.doi.org/10.3390/proceedings2181182.
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A biofilm is a layer of microorganisms attached to a surface and protected by a matrix of exopolysaccharides. Biofilm structures difficult the removal of microorganisms, thus the study of the type of structures formed throughout a biofilm life cycle is key to design elimination techniques. Also, the study of the inner mechanisms of a biofilm system is of the utmost importance in order to prevent harmful biofilms formation and enhance the properties of beneficial biofilms. This study must be achieved through the combination of mathematical modelling and experimental studies. Our work focuses on the study of biofilms formed by Listeria monocytogenes, a pathogen bacteria, specially relevant in food industry. Listeria is highly resistant to biocides and appears in common food surfaces even after decontamination processes. Their biofilms can develop quite different structures, from flat biofilms to clustered or honeycomb structures. In the present work, we develop 1D and 2D models that simulate the dynamics of biofilms formed by different strains of L. monocytogenes. All this models are solved with efficient numerical methods and robust numerical techniques, such as the Level Set method. The numerical re sults are compared with the experimental measurements obtained in the Instituto de Investigaciones Marinas, CSIC (Vigo, Spain), and the Micalis Institute, INRA (Massy, France).
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Chavez-Dozal, Alba, Clayton Gorman, Martina Erken, Peter D. Steinberg, Diane McDougald, and Michele K. Nishiguchi. "Predation Response of Vibrio fischeri Biofilms to Bacterivorus Protists." Applied and Environmental Microbiology 79, no. 2 (November 9, 2012): 553–58. http://dx.doi.org/10.1128/aem.02710-12.
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ABSTRACTVibrio fischeriproliferates in a sessile, stable community known as a biofilm, which is one alternative survival strategy of its life cycle. Although this survival strategy provides adequate protection from abiotic factors, marine biofilms are still susceptible to grazing by bacteria-consuming protozoa. Subsequently, grazing pressure can be controlled by certain defense mechanisms that confer higher biofilm antipredator fitness. In the present work, we hypothesized thatV. fischeriexhibits an antipredator fitness behavior while forming biofilms. Different predators representing commonly found species in aquatic populations were examined, including the flagellatesRhynchomonas nasutaandNeobodo designis(early biofilm feeders) and the ciliateTetrahymena pyriformis(late biofilm grazer).V. fischeribiofilms included isolates from both seawater and squid hosts (EuprymnaandSepiolaspecies). Our results demonstrate inhibition of predation by biofilms, specifically, isolates from seawater. Additionally, antiprotozoan behavior was observed to be higher in late biofilms, particularly toward the ciliateT. pyriformis; however, inhibitory effects were found to be widespread among all isolates tested. These results provide an alternative explanation for the adaptive advantage and persistence ofV. fischeribiofilms and provide an important contribution to the understanding of defensive mechanisms that exist in the out-of-host environment.
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Rodrigues, Sophie, Christine Paillard, Sabine Van Dillen, Ali Tahrioui, Jean-Marc Berjeaud, Alain Dufour, and Alexis Bazire. "Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study." Pathogens 7, no. 4 (November 26, 2018): 92. http://dx.doi.org/10.3390/pathogens7040092.
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Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A flow cell system was employed to grow biofilms to obtain both structural and transcriptomic views of the biofilms. We found that 3615 genes were differentially expressed, confirming that biofilm and planktonic lifestyles are very different. As expected, the differentially expressed genes included those involved in biofilm formation, such as motility- and polysaccharide synthesis-related genes. The data show that quorum sensing is probably mediated by the AI-2/LuxO system in V. tapetis biofilms. The expression of genes encoding the Type VI Secretion System and associated exported proteins are strongly induced, suggesting that V. tapetis activates this virulence factor when living in biofilm.
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Romeu, Maria João, João Morais, Vítor Vasconcelos, and Filipe Mergulhão. "Effect of Hydrogen Peroxide on Cyanobacterial Biofilms." Antibiotics 12, no. 9 (September 16, 2023): 1450. http://dx.doi.org/10.3390/antibiotics12091450.
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Although a range of disinfecting formulations is commercially available, hydrogen peroxide is one of the safest chemical agents used for disinfection in aquatic environments. However, its effect on cyanobacterial biofilms is poorly investigated. In this work, biofilm formation by two filamentous cyanobacterial strains was evaluated over seven weeks on two surfaces commonly used in marine environments: glass and silicone-based paint (Sil-Ref) under controlled hydrodynamic conditions. After seven weeks, the biofilms were treated with a solution of hydrogen peroxide (H2O2) to assess if disinfection could affect long-term biofilm development. The cyanobacterial biofilms appeared to be tolerant to H2O2 treatment, and two weeks after treatment, the biofilms that developed on glass by one of the strains presented higher biomass amounts than the untreated biofilms. This result emphasizes the need to correctly evaluate the efficiency of disinfection in cyanobacterial biofilms, including assessing the possible consequences of inefficient disinfection on the regrowth of these biofilms.
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Messersmith, Reid E., F. Connor Sage, James K. Johnson, Spencer A. Langevin, Ellen R. Forsyth, Meaghan T. Hart, and Christopher M. Hoffman. "Iron Sequestration by Galloyl–Silane Nano Coatings Inhibits Biofilm Formation of Sulfitobacter sp." Biomimetics 8, no. 1 (February 12, 2023): 79. http://dx.doi.org/10.3390/biomimetics8010079.
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Microbially-induced corrosion is the acceleration of corrosion induced by bacterial biofilms. The bacteria in the biofilms oxidize metals on the surface, especially evident with iron, to drive metabolic activity and reduce inorganic species such as nitrates and sulfates. Coatings that prevent the formation of these corrosion-inducing biofilms significantly increase the service life of submerged materials and significantly decrease maintenance costs. One species in particular, a member of the Roseobacter clade, Sulfitobacter sp., has demonstrated iron-dependent biofilm formation in marine environments. We have found that compounds that contain the galloyl moiety can prevent Sulfitobacter sp. biofilm formation by sequestering iron, thus making a surface unappealing for bacteria. Herein, we have fabricated surfaces with exposed galloyl groups to test the effectiveness of nutrient reduction in iron-rich media as a non-toxic method to reduce biofilm formation.
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Neves, Ana R., Luciana C. Gomes, Sara I. Faria, João Sousa, Raquel Ruivo, Inês Páscoa, Madalena Pinto, et al. "Antifouling Marine Coatings with a Potentially Safer and Sustainable Synthetic Polyphenolic Derivative." Marine Drugs 20, no. 8 (August 5, 2022): 507. http://dx.doi.org/10.3390/md20080507.
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The development of harmless substances to replace biocide-based coatings used to prevent or manage marine biofouling and its unwanted consequences is urgent. The formation of biofilms on submerged marine surfaces is one of the first steps in the marine biofouling process, which facilitates the further settlement of macrofoulers. Anti-biofilm properties of a synthetic polyphenolic compound, with previously described anti-settlement activity against macrofoulers, were explored in this work. In solution this new compound was able to prevent biofilm formation and reduce a pre-formed biofilm produced by the marine bacterium, Pseudoalteromonas tunicata. Then, this compound was applied to a marine coating and the formation of P. tunicata biofilms was assessed under hydrodynamic conditions to mimic the marine environment. For this purpose, polyurethane (PU)-based coating formulations containing 1 and 2 wt.% of the compound were prepared based on a prior developed methodology. The most effective formulation in reducing the biofilm cell number, biovolume, and thickness was the PU-based coating containing an aziridine-based crosslinker and 2 wt.% of the compound. To assess the marine ecotoxicity impact of this compound, its potential to disrupt endocrine processes was evaluated through the modulation of two nuclear receptors (NRs), peroxisome proliferator-activated receptor γ (PPARγ), and pregnane X receptor (PXR). Transcriptional activation of the selected NRs upon exposure to the polyphenolic compound (10 µM) was not observed, thus highlighting the eco-friendliness towards the addressed NRs of this new dual-acting anti-macro- and anti-microfouling agent towards the addressed NRs.
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Amin, Zarina, Nur Ariffah Waly, and Sazmal Effendi Arshad. "Biofilm Inhibition and Antimicrobial Properties of Silver-Ion-Exchanged Zeolite A against Vibrio spp Marine Pathogens." Applied Sciences 11, no. 12 (June 14, 2021): 5496. http://dx.doi.org/10.3390/app11125496.
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A challenging problem in the aquaculture industry is bacterial disease outbreaks, which result in the global reduction in fish supply and foodborne outbreaks. Biofilms in marine pathogens protect against antimicrobial treatment and host immune defense. Zeolites are minerals of volcanic origin made from crystalline aluminosilicates, which are useful in agriculture and in environmental management. In this study, silver-ion-exchanged zeolite A of four concentrations; 0.25 M (AgZ1), 0.50 M (AgZ2), 1.00 M (AgZ3) and 1.50 M (AgZ4) were investigated for biofilm inhibition and antimicrobial properties against two predominant marine pathogens, V. campbelli and V. parahemolyticus, by employing the minimum inhibitory concentration (MIC) and crystal violet biofilm quantification assays as well as scanning electron microscopy. In the first instance, all zeolite samples AgZ1–AgZ4 showed antimicrobial activity for both pathogens. For V. campbellii, AgZ4 exhibited the highest MIC at 125.00 µg/mL, while for V. parahaemolyticus, the highest MIC was observed for AgZ3 at 62.50 µg/mL. At sublethal concentration, biofilm inhibition of V. campbelli and V. parahemolyticus by AgZ4 was observed at 60.2 and 77.3% inhibition, respectively. Scanning electron microscopy exhibited profound structural alteration of the biofilm matrix by AgZ4. This is the first known study that highlights the potential application of ion-exchanged zeolite A against marine pathogens and their biofilms.
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Vladkova, Todorka G., Deyan M. Monov, Danail T. Akuzov, Iliana A. Ivanova, and Dilyana Gospodinova. "Comparative Study of the Marinobacter hydrocarbonoclasticus Biofilm Formation on Antioxidants Containing Siloxane Composite Coatings." Materials 15, no. 13 (June 27, 2022): 4530. http://dx.doi.org/10.3390/ma15134530.
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No systematic study of antioxidant containing coatings and their anti-biofilm action has been reported so far. The utilization of antioxidants in protective coatings to inhibit marine biofilm formation is a current challenge. The aim of this preliminary study was to prepare, characterize and compare the efficiency of low adhesive siloxane composite coatings equally loaded with different antioxidants against mono-species biofilms formation. Most often participating in the marine biofilms formation, Marinobacter hydrocarbonoclasticus was the test bacterium. Both the biofilm covered surface area (BCSA) and corrected total cell fluorescence (CTCF) (by fluorescent microscopy) were selected as the parameters for quantification of the biofilm after 1 h and 4 h incubation. Differing extents of altered surface characteristics (physical-chemical; physical-mechanical) and the specific affection of M. hydrocarbonoclasticus biofilm formation in both reduction and stimulation, were found in the studied antioxidant containing coatings, depending on the chemical nature of the used antioxidant. It was concluded that not all antioxidants reduce mono-species biofilm formation; antioxidant chemical reactivity stipulates the formation of an altered vulcanization network of the siloxane composites and thus microbial adhesion which influences the surface characteristics of the vulcanized coatings; and low surface energy combined with a low indentation elastic modulus are probably pre-requisites of low microbial adhesion.
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Hayek, Mahmoud, Marie Salgues, Frédéric Habouzit, Sandrine Bayle, Jean-Claude Souche, Klartjee De Weerdt, and Sylvain Pioch. "L’influence de la carbonatation sur la biocolonisation de matériaux cimentaires dans le milieu marin." Matériaux & Techniques 108, no. 2 (2020): 202. http://dx.doi.org/10.1051/mattech/2020020.
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Les ingénieurs spécialisés en génie civil doivent intégrer dans leur design des mesures de protection de la biodiversité marine de qui autorise le concept d’écoconception d’infrastructures marines respectueuses de l’environnement. Les matériaux cimentaires sont privilégiés pour concevoir les infrastructures marines et interagissent avec le milieu marin. Ces structures seront colonisées par des micro-organismes et macroorganismes marins. Dans un premier temps, les organismes forment un biofilm à la surface du béton en fonction des facteurs environnementaux et des propriétés physico-chimiques du matériau. Dans cette étude, il a été démontré que la pré-carbonatation des matériaux cimentaires accélère la croissance des micro-organismes formant le biofilm à leur surface en abaissant le pH de la surface. Il a été démontré en laboratoire que la colonisation de la surface par des micro-organismes augmente également l’hydrophobicité de la surface et pourrait ainsi améliorer la durabilité du matériau en diminuant l’absorption d’eau de mer contenant des agents agressifs.
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Staal, M., R. Thar, M. Kühl, M. C. M. van Loosdrecht, G. Wolf, J. F. C. de Brouwer, and J. W. Rijstenbil. "Carbon isotope fractionation in developing natural phototrophic biofilms." Biogeosciences Discussions 4, no. 1 (January 24, 2007): 69–98. http://dx.doi.org/10.5194/bgd-4-69-2007.
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Abstract. Natural phototrophic biofilms are influenced by a broad array of abiotic and biotic factors and vary over temporal and spatial scales. Different developmental stages can be distinguished and growth rates will vary due to the thickening of the biofilm, which are expected to lead to a limitation of light or mass transport. In this study it is shown that a variation of the availability of CO2 leads to a shift in fractionation, thereby affecting δ13C signatures during the successive developmental stages. For phototrophic freshwater biofilms it was found that the δ13C value became less negative with the thickening of the biofilm, while the opposite trend in δ13C values was found in marine biofilms. Modeling and pH profiling indicated that the change in the freshwater system was caused by an increase in CO2 limitation resulting in an increase of HCO3− as C-source. The opposite trend in the marine system could be explained by a higher heterotrophic biomass and activity causing a higher carbon recycling and thereby lower δ13C values. We conclude that δ13C was more related to the net areal photosynthesis rate and carbon recycling, rather than to the growth rate of the biofilms.
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Gomes, Luciana C., and Filipe J. M. Mergulhão. "A Selection of Platforms to Evaluate Surface Adhesion and Biofilm Formation in Controlled Hydrodynamic Conditions." Microorganisms 9, no. 9 (September 21, 2021): 1993. http://dx.doi.org/10.3390/microorganisms9091993.
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The early colonization of surfaces and subsequent biofilm development have severe impacts in environmental, industrial, and biomedical settings since they entail high costs and health risks. To develop more effective biofilm control strategies, there is a need to obtain laboratory biofilms that resemble those found in natural or man-made settings. Since microbial adhesion and biofilm formation are strongly affected by hydrodynamics, the knowledge of flow characteristics in different marine, food processing, and medical device locations is essential. Once the hydrodynamic conditions are known, platforms for cell adhesion and biofilm formation should be selected and operated, in order to obtain reproducible biofilms that mimic those found in target scenarios. This review focuses on the most widely used platforms that enable the study of initial microbial adhesion and biofilm formation under controlled hydrodynamic conditions—modified Robbins devices, flow chambers, rotating biofilm devices, microplates, and microfluidic devices—and where numerical simulations have been used to define relevant flow characteristics, namely the shear stress and shear rate.
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Campana, Raffaella, Gianfranco Favi, Wally Baffone, and Simone Lucarini. "Marine Alkaloid 2,2-Bis(6-bromo-3-indolyl) Ethylamine and Its Synthetic Derivatives Inhibit Microbial Biofilms Formation and Disaggregate Developed Biofilms." Microorganisms 7, no. 2 (January 23, 2019): 28. http://dx.doi.org/10.3390/microorganisms7020028.
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The antimicrobial activity of the marine bisindole alkaloid 2,2-bis(6-bromo-3-indolyl) ethylamine (1) and related synthetic analogues (compounds 2–8) against target microorganisms was investigated by Minimum Inhibitory Concentration (MIC) determination. Compound 1 showed the greatest antimicrobial activity with the lowest MIC (8 mg/L) against Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae, while the derivatives exhibited higher MICs values (from 16 to 128 mg/L). Compounds 1, 3, 4, and 8, the most active ones, were then tested against E. coli, S. aureus, K. pneumoniae, and Candida albicans during biofilms formation as well as on 24 h developed biofilms. The natural alkaloid 1 inhibited the biofilm formation of all the tested microorganisms up to 82.2% and disaggregated biofilms of E. coli, S. aureus, K. pneumoniae, and C. albicans after 30 min of contact, as assessed by viable plate count and crystal violet (CV) staining (optical density at 570 nm). Synthetic derivatives 3, 4, and 8 displayed anti-biofilm activity toward individual bacterial populations. This study highlights the potential of marine bisindole alkaloid 1 as anti-biofilm agent and shows, through a preliminary structure activity relationship (SAR), the importance of halogens and ethylamine side chain for the antimicrobial and antibiofilm activities of this bisindole series.
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Wang, Shougang, Xiaoyan Su, Han Cui, Meng Wang, Xiaoli Hu, Wei Ding, and Weipeng Zhang. "Microbial Richness of Marine Biofilms Revealed by Sequencing Full-Length 16S rRNA Genes." Genes 13, no. 6 (June 12, 2022): 1050. http://dx.doi.org/10.3390/genes13061050.
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Marine biofilms are a collective of microbes that can grow on many different surfaces immersed in marine environments. Estimating the microbial richness and specificity of a marine biofilm community is a challenging task due to the high complexity in comparison with seawater. Here, we compared the resolution of full-length 16S rRNA gene sequencing technique of a PacBio platform for microbe identification in marine biofilms with the results of partial 16S rRNA gene sequencing of traditional Illumina PE250 platform. At the same time, the microbial richness, diversity, and composition of adjacent seawater communities in the same batch of samples were analyzed. Both techniques revealed higher species richness, as reflected by the Chao1 index, in the biofilms than that in the seawater communities. Moreover, compared with Illumina sequencing, PacBio sequencing detected more specific species for biofilms and less specific species for seawater. Members of Vibrio, Arcobacter, Photobacterium, Pseudoalteromonas, and Thalassomonas were significantly enriched in the biofilms, which is consistent with the previous understanding of species adapted to a surface-associated lifestyle and validates the taxonomic analyses in the current study. To conclude, the full-length sequencing of 16S rRNA genes has probably a stronger ability to analyze more complex microbial communities, such as marine biofilms, the species richness of which has probably been under-estimated in previous studies.
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Wu, Z., Y. Wu, Y. Huang, J. He, P. Su, and D. Feng. "Insights into the planktonic to sessile transition in a marine biofilm-forming Pseudoalteromonas isolate using comparative proteomic analysis." Aquatic Microbial Ecology 86 (April 8, 2021): 69–84. http://dx.doi.org/10.3354/ame01959.
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Bacterial biofilms play an important role in marine biofouling. The formation of a biofilm starts when marine bacterial cells transition from a planktonic to an attached state. However, the molecular mechanisms involved in this transition are poorly understood. Here, 51 strains of marine bacteria were isolated from natural biofilms growing on submerged artificial surfaces (glass slides, epoxy panels, and bridge pillars) and evaluated for their biofilm-forming capacity. Eleven strains formed relatively strong biofilms and 16S rRNA gene sequence analysis indicated that they belonged to the genera Leisingera, Roseobacter, Pseudoalteromonas, Alteromonas, Tenacibaculum, Vibrio, Chryseobacterium, Aquimarina, and Acinetobacter. Strain Pseudoalteromonas sp. W-7 showed efficient and rapid attachment and was therefore chosen for further study. An iTRAQ-based comparative proteomic analysis of planktonic and attached strain W-7 cells was carried out. A total of 3468 proteins were identified, of which 163 showed significant differential expression (120 down-regulated and 43 up-regulated in attached cells relative to planktonic cells). KEGG (Kyoto encyclopedia of genes and genomes) analysis indicated that pyruvate metabolism, carbon fixation, and carbon metabolism were significantly affected in attached cells. Up-regulated proteins such as UTP-glucose-1-phosphate uridylyltransferase, acetyltransferase component of pyruvate dehydrogenase complex, OmpA-like protein, and acetyl-coenzyme A synthetase may be important during initial adhesion. Our findings provide a deeper understanding of the planktonic to sessile transition of marine fouling bacteria.
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Robika, Robika, Rahmad Lingga, and Budi Afriyansyah. "Identification of Biofilm-Producing Bacteria From Nangka Island Marine Water in District of Bangka Tengah." JURNAL PEMBELAJARAN DAN BIOLOGI NUKLEUS 8, no. 1 (March 13, 2022): 179–91. http://dx.doi.org/10.36987/jpbn.v8i1.2492.
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Bacterial community is an important element of an ecosystem both on land and in water. In aquatic ecosystems, bacteria that have the ability to produce biofilms have the advantage of being able to easily attach on a substrate. The main function of biofilm is assisting nutrition absorption from water and facilitating bacteria surviveness from unfavorable environmental conditions. This research was conducted to isolate and identify and test the potential of bacteria to form biofilms in vitro. The methodological steps included measuring the physical-chemical parameters of the waters; isolation by pour plating method; characterization and identification based on morphological, biochemical and Gram staining; as well as testing the activity of biofilm formation by reading technique using microplate reader. The highest bacterial abundance was found at Station 3 (muddy substrate) which was 3.3x106 cfu/ml. Bacterial isolates that had the highest ability to form biofilms in vitro were Bb3, Bb4 and Bb1 isolates with values of 0.3315, 0.2370) and 0.2131, respectively. Bacteria that have the potential to form biofilms from various substrates in the waters of Nangka Island belong to Alcaligenes and Meniscus genera. From the results of the study, it can be concluded that bacteria from rocky substrates have the ability to produce biofilms better than isolates from other substrates.
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Shikuma, N. J., and M. G. Hadfield. "Temporal variation of an initial marine biofilm community and its effects on larval settlement and metamorphosis of the tubeworm Hydroides elegans." Biofilms 2, no. 4 (October 2005): 231–38. http://dx.doi.org/10.1017/s1479050506002018.
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Planktonic larvae of many sessile marine invertebrates settle and metamorphose preferentially on surfaces covered by bacterial biofilms. The polychaete tubeworm Hydroides elegans is induced to settle by biofilms and is the primary colonizer of newly submerged surfaces in the succession of macrofouling invertebrates in Pearl Harbor, Hawaii, USA. This study examines the succession of bacterial community composition and cell density of marine biofilms, and how temporal changes in biofilms affect settlement of H. elegans. Settlement assays of H. elegans were conducted on naturally formed biofilms of increasing age from Pearl Harbor. Denaturing gradient gel electrophoresis and epifluoresence microscopy were used to identify community composition and densities of bacterial cells in biofilms. Results of this study suggest that increasing densities of a stable community, rather than a shift in dominant species composition of biofilm bacteria, are probably responsible for the primary colonization of submerged surfaces by H. elegans in Pearl Harbor. However, the current data leave open the question of why larvae of other biofouling invertebrate species known to settle in response to biofilms recruit to surfaces only at later times.
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Mai-Prochnow, Anne, Jeremy S. Webb, Belinda C. Ferrari, and Staffan Kjelleberg. "Ecological Advantages of Autolysis during the Development and Dispersal of Pseudoalteromonas tunicata Biofilms." Applied and Environmental Microbiology 72, no. 8 (August 2006): 5414–20. http://dx.doi.org/10.1128/aem.00546-06.
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ABSTRACT In the ubiquitous marine bacterium Pseudoalteromonas tunicata, subpopulations of cells are killed by the production of an autocidal protein, AlpP, during biofilm development. Our data demonstrate an involvement of this process in two parameters, dispersal and phenotypic diversification, which are of importance for the ecology of this organism and for its survival within the environment. Cell death in P. tunicata wild-type biofilms led to a major reproducible dispersal event after 192 h of biofilm development. The dispersal was not observed with a ΔAlpP mutant strain. Using flow cytometry and the fluorescent dye DiBAC4(3), we also show that P. tunicata wild-type cells that disperse from biofilms have enhanced metabolic activity compared to those cells that disperse from ΔAlpP mutant biofilms, possibly due to nutrients released from dead cells. Furthermore, we report that there was considerable phenotypic variation among cells dispersing from wild-type biofilms but not from the ΔAlpP mutant. Wild-type cells that dispersed from biofilms showed significantly increased variations in growth, motility, and biofilm formation, which may be important for successful colonization of new surfaces. These findings suggest for the first time that the autocidal events mediated by an antibacterial protein can confer ecological advantages to the species by generating a metabolically active and phenotypically diverse subpopulation of dispersal cells.
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Nandakumar, Kanavillil, Hideki Obika, Akihiro Utsumi, Toshihiko Ooie, and Tetsuo Yano. "In Vitro Laser Ablation of Natural Marine Biofilms." Applied and Environmental Microbiology 70, no. 11 (November 2004): 6905–8. http://dx.doi.org/10.1128/aem.70.11.6905-6908.2004.
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ABSTRACT We studied the efficiency of pulsed low-power laser irradiation of 532 nm from an Nd:YAG (neodymium-doped yttrium-aluminum-garnet) laser to remove marine biofilm developed on titanium and glass coupons. Natural biofilms with thicknesses of 79.4 � 27.8 μm (titanium) and 107.4 � 28.5 μm (glass) were completely disrupted by 30 s of laser irradiation (fluence, 0.1 J/cm2). Laser irradiation significantly reduced the number of diatoms and bacteria in the biofilm (paired t test; P < 0.05). The removal was better on titanium than on glass coupons.
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Patra, Anupam, Jhilik Das, Nupur Rani Agrawal, Gajraj Singh Kushwaha, Mrinmoy Ghosh, and Young-Ok Son. "Marine Antimicrobial Peptides-Based Strategies for Tackling Bacterial Biofilm and Biofouling Challenges." Molecules 27, no. 21 (November 3, 2022): 7546. http://dx.doi.org/10.3390/molecules27217546.
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An assemblage nexus of microorganisms enclosed in a composite extracellular polymeric matrix is called as a biofilm. The main factor causing biological fouling, or biofouling, is biofilms. Biofilm-mediated biofouling is a significant detrimental issue in several industries, including the maritime environment, industrial facilities, water treatment facilities, and medical implants. Conventional antibacterial remedies cannot wholly eradicate bacterial species owing to the structural rigidity of biofilm and the eventual growth of antibiotic-resistant microorganisms. Consequently, several approaches to disrupt the biofilm have been investigated to address this particular phenomenon. Antimicrobial peptides (AMPs) have emerged as a promising contender in this category, offering several advantages over traditional solutions, including broad-spectrum action and lack of antibiotic resistance. Because biofouling significantly impacts the marine industry, AMPs derived from marine sources may be suitable natural inhibitors of bacterial proliferation. In this article, we discuss the range of physicochemical and structural diversity and the model of action seen in marine AMPs. This makes them an appealing strategy to mitigate biofilm and biofilm-mediated biofouling. This review also systematically summarizes recent research on marine AMPs from vertebrates and invertebrates and their industrial significance, shedding light on developing even better anti-biofouling materials shortly.
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Sneed, Jennifer M., Koty H. Sharp, Kimberly B. Ritchie, and Valerie J. Paul. "The chemical cue tetrabromopyrrole from a biofilm bacterium induces settlement of multiple Caribbean corals." Proceedings of the Royal Society B: Biological Sciences 281, no. 1786 (July 7, 2014): 20133086. http://dx.doi.org/10.1098/rspb.2013.3086.
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Microbial biofilms induce larval settlement for some invertebrates, including corals; however, the chemical cues involved have rarely been identified. Here, we demonstrate the role of microbial biofilms in inducing larval settlement with the Caribbean coral Porites astreoides and report the first instance of a chemical cue isolated from a marine biofilm bacterium that induces complete settlement (attachment and metamorphosis) of Caribbean coral larvae. Larvae settled in response to natural biofilms, and the response was eliminated when biofilms were treated with antibiotics. A similar settlement response was elicited by monospecific biofilms of a single bacterial strain, Pseudoalteromonas sp. PS5, isolated from the surface biofilm of a crustose coralline alga. The activity of Pseudoalteromonas sp. PS5 was attributed to the production of a single compound, tetrabromopyrrole (TBP), which has been shown previously to induce metamorphosis without attachment in Pacific acroporid corals. In addition to inducing settlement of brooded larvae ( P. astreoides ), TBP also induced larval settlement for two broadcast-spawning species, Orbicella (formerly Montastraea ) franksi and Acropora palmata , indicating that this compound may have widespread importance among Caribbean coral species.
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DEVIVILLA, SUMA, MANJUSHA LEKSHMI, SANATH H. KUMAR, RAJENDRAN K. VALAPPIL, SIBNARAYAN DAM ROY, and BINAYA B. NAYAK. "Effect of Sodium Hypochlorite on Biofilm-Forming Ability of Histamine-Producing Bacteria Isolated from Fish." Journal of Food Protection 82, no. 8 (July 23, 2019): 1417–22. http://dx.doi.org/10.4315/0362-028x.jfp-19-101.
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ABSTRACT Histamine poisoning occurs when temperature-abused marine fish containing elevated levels of histamine are consumed. Histamine-producing bacteria found in fish can colonize processing surfaces and form biofilms. In this study, the biofilm-forming abilities of histamine-producing bacteria from Indian mackerel (Rastrelliger kanagurta) and the effect of hypochlorite treatment on biofilm formation were studied. The isolates of this study produced histamine in the range of 471 to 2,126 ppm. The histidine decarboxylase gene hdc was detected in all isolates producing histamine except in one strain each of Psychrobacter pulmonis and Proteus vulgaris. All isolates tested in this study produced moderate biofilms under control conditions, whereas exposure to 1 and 3 ppm of sodium hypochlorite significantly enhanced biofilm formation. However, exposure to 5 ppm of sodium hypochlorite showed an inhibitory effect on biofilm formation by all the isolates except Klebsiella variicola. The results of this study suggest that histamine-producing bacteria can form stable biofilms and that this activity may be enhanced by the application of low levels of sodium hypochlorite, a phenomenon that might influence the persistence of histamine-producing bacteria in fish processing areas.
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Tran, Tam M. T., Russell S. Addison, Rohan A. Davis, and Bernd H. A. Rehm. "Bromotyrosine-Derived Metabolites from a Marine Sponge Inhibit Pseudomonas aeruginosa Biofilms." International Journal of Molecular Sciences 24, no. 12 (June 16, 2023): 10204. http://dx.doi.org/10.3390/ijms241210204.
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Pseudomonas aeruginosa forms stable biofilms, providing a major barrier for multiple classes of antibiotics and severely impairing treatment of infected patients. The biofilm matrix of this Gram-negative bacterium is primarily composed of three major exopolysaccharides: alginate, Psl, and Pel. Here, we studied the antibiofilm properties of sponge-derived natural products ianthelliformisamines A–C and their combinations with clinically used antibiotics. Wild-type P. aeruginosa strain and its isogenic exopolysaccharide-deficient mutants were employed to determine the interference of the compounds with biofilm matrix components. We identified that ianthelliformisamines A and B worked synergistically with ciprofloxacin to kill planktonic and biofilm cells. Ianthelliformisamines A and B reduced the minimum inhibitory concentration (MIC) of ciprofloxacin to 1/3 and 1/4 MICs, respectively. In contrast, ianthelliformisamine C (MIC = 53.1 µg/mL) alone exhibited bactericidal effects dose-dependently on both free-living and biofilm populations of wild-type PAO1, PAO1ΔpslA (Psl deficient), PDO300 (alginate overproducing and mimicking clinical isolates), and PDO300Δalg8 (alginate deficient). Interestingly, the biofilm of the clinically relevant mucoid variant PDO300 was more susceptible to ianthelliformisamine C than strains with impaired polysaccharide synthesis. Ianthelliformisamines exhibited low cytotoxicity towards HEK293 cells in the resazurin viability assay. Mechanism of action studies showed that ianthelliformisamine C inhibited the efflux pump of P. aeruginosa. Metabolic stability analyses indicated that ianthelliformisamine C is stable and ianthelliformisamines A and B are rapidly degraded. Overall, these findings suggest that the ianthelliformisamine chemotype could be a promising candidate for the treatment of P. aeruginosa biofilms.
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Bomchil, Natalia, Paula Watnick, and Roberto Kolter. "Identification and Characterization of a Vibrio cholerae Gene, mbaA, Involved in Maintenance of Biofilm Architecture." Journal of Bacteriology 185, no. 4 (February 15, 2003): 1384–90. http://dx.doi.org/10.1128/jb.185.4.1384-1390.2003.
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ABSTRACT The formation of biofilms is thought to play a key role in the environmental survival of the marine bacterium Vibrio cholerae. Although the factors involved in V. cholerae attachment to abiotic surfaces have been extensively studied, relatively little is known about the mechanisms involved in the subsequent maturation of the biofilms. Here we report the identification of a novel gene, which we have named mbaA (for maintenance of biofilm architecture), that plays a role in the formation and maintenance of the highly organized three-dimensional architecture of V. cholerae El Tor biofilms. We demonstrate that although the absence of mbaA does not significantly affect the initial attachment of cells onto the surface, it leads to the formation of biofilms that lack the typical structure, including the pillars of cells separated by fluid-filled channels that are evident in mature wild-type biofilms. Microscopic analysis indicates that the absence of mbaA leads to an increase in the amount of extracellular matrix material in the biofilms. The predicted mbaA product is a member of a family of regulatory proteins, containing GGDEF and EAL domains, suggesting that MbaA regulates the synthesis of some component of the biofilm matrix.
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Caruso, Gabriella. "Microbial Colonization in Marine Environments: Overview of Current Knowledge and Emerging Research Topics." Journal of Marine Science and Engineering 8, no. 2 (January 24, 2020): 78. http://dx.doi.org/10.3390/jmse8020078.
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Microbial biofilms are biological structures composed of surface-attached microbial communities embedded in an extracellular polymeric matrix. In aquatic environments, the microbial colonization of submerged surfaces is a complex process involving several factors, related to both environmental conditions and to the physical-chemical nature of the substrates. Several studies have addressed this issue; however, more research is still needed on microbial biofilms in marine ecosystems. After a brief report on environmental drivers of biofilm formation, this study reviews current knowledge of microbial community attached to artificial substrates, as obtained by experiments performed on several material types deployed in temperate and extreme polar marine ecosystems. Depending on the substrate, different microbial communities were found, sometimes highlighting the occurrence of species-specificity. Future research challenges and concluding remarks are also considered. Emphasis is given to future perspectives in biofilm studies and their potential applications, related to biofouling prevention (such as cell-to-cell communication by quorum sensing or improved knowledge of drivers/signals affecting biological settlement) as well as to the potential use of microbial biofilms as sentinels of environmental changes and new candidates for bioremediation purposes.
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Li, Qing-Chao, Bo Wang, Yan-Hua Zeng, Zhong-Hua Cai, and Jin Zhou. "The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment." International Journal of Molecular Sciences 23, no. 7 (March 30, 2022): 3837. http://dx.doi.org/10.3390/ijms23073837.
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Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose–lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.
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Daboor, Said M., Renee Raudonis, Alejandro Cohen, John R. Rohde, and Zhenyu Cheng. "Marine Bacteria, A Source for Alginolytic Enzyme to Disrupt Pseudomonas aeruginosa Biofilms." Marine Drugs 17, no. 5 (May 24, 2019): 307. http://dx.doi.org/10.3390/md17050307.
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Pseudomonas aeruginosa biofilms are typically associated with the chronic lung infection of cystic fibrosis (CF) patients and represent a major challenge for treatment. This opportunistic bacterial pathogen secretes alginate, a polysaccharide that is one of the main components of its biofilm. Targeting this major biofilm component has emerged as a tempting therapeutic strategy for tackling biofilm-associated bacterial infections. The enormous potential in genetic diversity of the marine microbial community make it a valuable resource for mining activities responsible for a broad range of metabolic processes, including the alginolytic activity responsible for degrading alginate. A collection of 36 bacterial isolates were purified from marine water based on their alginolytic activity. These isolates were identified based on their 16S rRNA gene sequences. Pseudoalteromonas sp. 1400 showed the highest alginolytic activity and was further confirmed to produce the enzyme alginate lyase. The purified alginate lyase (AlyP1400) produced by Pseudoalteromonas sp. 1400 showed a band of 23 KDa on a protein electrophoresis gel and exhibited a bifunctional lyase activity for both poly-mannuronic acid and poly-glucuronic acid degradation. A tryptic digestion of this gel band analyzed by liquid chromatography-tandem mass spectrometry confirmed high similarity to the alginate lyases in polysaccharide lyase family 18. The purified alginate lyase showed a maximum relative activity at 30 °C at a slightly acidic condition. It decreased the sodium alginate viscosity by over 90% and reduced the P. aeruginosa (strain PA14) biofilms by 69% after 24 h of incubation. The combined activity of AlyP1400 with carbenicillin or ciprofloxacin reduced the P. aeruginosa biofilm thickness, biovolume and surface area in a flow cell system. The present data revealed that AlyP1400 combined with conventional antibiotics helped to disrupt the biofilms produced by P. aeruginosa and can be used as a promising combinational therapeutic strategy.