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.

The aim of this work was to study the community level physiological profile of a developing oral biofilm. Mixed-species biofilms, derived from human saliva, were grown in a constant-depth film fermentor for up to 240 h. Biolog GP2 microplates were inoculated with saliva or homogenized biofilms and incubated at 37 °C. The results showed that a biofilm community could utilize a range of substrates more diverse than those of their planktonic counterparts. Following the construction of dendrograms, a temporal relationship was demonstrated between the inoculum and biofilms, and the difference in communities over time was also resolved by using an eight-digit code of positive carbon sources. The diversity of the populations could be determined through the use of the community level physiological profile and the treatment of the data may augment the interpretation of the results. Methods such as community level physiological profiling may provide a valuable insight into the composition of biofilm communities associated with oral health and disease.

The effect of growth and detachment on formation of large-scale biofilm structure

Biofilm cohesive energy density determination using a novel atomic force microscopy methodology

Fluorescence correlation spectroscopy under two-photon excitation for the study of diffusion and reactivity of bacteriophage inside bacterial biofilms

Biothermodynamic characterization and dynamic analysis of biofilms using calorimetry

Biomimetic antifouling coatings for sensor surfaces for water monitoring: performance control in defined biofilm cultures and under real environmental conditions

The contribution of rpos to formation of Escherichia coli biofilms

Synergistic effects in mixed Escherichia coli biofilms: conjugative plasmid transfer drives biofilm expansion

The universal stress protein PA3309 in Pseudomonas aeruginosa is induced in biofilms

Extracellular polymeric substances from biofilms on membranes in waste-water treatment plants

Biofilm-to-planktonic cell yield: a strategy for proliferation

Physiological and phylogenetic characterization of the dispersed and loosely attached fraction of activated sludge flocs

Towards a deterministic model of biofilm detachment: an experimental study

Effect of backwash on the characteristics of biofilm in a biological activated filter reactor using elemental sulfur particles

Process performance and biomass properties in membrane-aerated bioreactors

Bioaugmentation via conjugation in biofilms treating 3-chloroaniline: effects of selective pressure

Effect of phosphorus on biofilm growth in a completely mixed biofilm reactor

Impacts of biofilm development on reactive transport in porous media under variable flow regimens

Influence of biofilms on colloid mobility in the subsurface

Biofilms in amendable in situ microcosms indicate relevant electron acceptor processes at a BTEX-contaminated aquifer

Functional biodiversity of complex biofilms grown on polychlorinated biphenyl oil

Identification and characterization of biofilm formation phenotypes of several clinically relevant Streptococcus pyogenes serotype strains

Selected probiotic bacteria disrupt biofilm development of vancomycin-resistant Enterococcus faecium

Comparison of the extracellular polymeric substances of Candida albicans and Candida dubliniensis biofilms

Influence of quorum-sensing regulated production of an antimicrobial component by Serratia plymuthica on establishment of dual species biofilms with Escherichia coli

Biofilm formation by the thermophilic and cellulolytic actinomycete Thermobifida fusca

Biomonitoring of bacterial contamination on different surfaces of food-processing machines

Role of the flagella during the adhesion of Listeria monocytogenes EGD-e to inert surfaces after cultivation at different pHs and temperatures

Adhesion of Saccharomyces cerevisiae to stainless steel: influence of surface properties

Investigating the mechanical strength of biofilms with fluid dynamic gauging

Three-dimensional biofilm model with individual cells and continuum extracellular polymeric substances matrix

A three-dimensional computer model analysis of four hypothetical biofilm detachment mechanisms

Modelling biofilm growth, detachment and fluid flow in a cross-section of tube reactors

Biofilm games

A rheological study was performed on biofilms of mucoid Pseudomonas aeruginosa strains producing high molecular weight alginate as the major polysaccharide component of the extracellular polymeric substances (EPS). Environmental strain SG81 and clinical strain FRD1 produced O-acetylated alginate, and mutant FRD1153 derived from strain FRD1 was defective in alginate acetylation. Confluent biofilms were prepared by cultivating the bacteria at 36 °C for 24 h on membrane filters placed on Pseudomonas isolation agar. The rheological properties of these pure culture biofilms attached to the membrane filters were analysed using a rotating disc rheometer. The biofilms of all mucoid strains showed viscoelastic properties, with polymer (alginate) cross-linking caused predominantly by physical interactions in the form of entanglements. In dynamic frequency-sweep tests, we observed time-dependent plateau regimens, describing the dynamics of network structures. From these data, we could derive the concentration of elastically effective polymer chains as 5 (±1) x 1019 chains/l (limits are standard deviation) for 24 h old biofilms of P. aeruginosa SG81. Relaxation processes predicted an average lifetime of junction points of the order of 16 (±10) s. Pseudomona aeruginosa FRD1 revealed a more elastic polymer network when compared with the acetylation-defective strain FRD1153, which had a more viscous biofilm structure. With calcium (10 mmol/l) added to the growth medium, enhanced biofilm stability was observed, which was based mainly on Coulomb interactions between divalent calcium ions and the carboxylate groups of alginate, with entanglements making only minor contributions. The calcium-induced increase in polymer network stability was greater in biofilms of P. aeruginosa FRD1 than in the acetylation-defective strain FRD1153. These results indicate that acetyl groups as low molecular weight substituents of alginate polymers strongly influence the rheological behaviour of mucoid P. aeruginosa biofilms and are involved in the stabilization of polymer networks of the EPS matrix in both the absence and the presence of calcium ions.

This list includes conferences that had been announced at the time of going to press. We are happy to include details of other biofilm-related conferences – please send details of these to the editor-in-chief.