Biofilm community

Wolfaardt GM, JR Lawrence, RD Robarts, DE Caldwell (1995) Bioaccumulation of the herbicide diclofop in extracellular polymers and its utilization by a biofilm community during starvation. Appl Environ Microbiol 61 152-158. 

Massol-Deya A, R Weller, L Rfos-Hernandez, J-Z Zhou, RE Hickey, JM Tiedje (1997) Succession and convergence of biofilm communities in fixed-film reactors treating aromatic hydrocarbons in groundwater. Appl Environ Microbiol 63 270-276. 

In order to understand current approaches for prevention and control of biofilms, we must first consider the reasons for the failure of conventional antimicrobial protocols. There are thought to be three main reasons as to why biofilm bacteria out-survive their planktonic counterparts during antimicrobial treatments (reviewed by McBain et a/.16).These are i) poor penetration of antimicrobial compounds due to the presence and turn-over of exopolymer slime (glycocalyx) ii) the imposition of extreme nutrient limitation within the depths of the biofilm community and the co-incident expression of metabolically-dormant, recalcitrant phenotypes and (iii) the expression of attachment-specific phenotypes that are radically different and intrinsically less susceptible than unattached ones. 

D. J. Stickler, in Biofilms Community Interactions and Control, ed. J. Wimpenny, P. Handley, P. Gilbert, H. Lappin-Scott and M. Jones, Bioline, Cardiff, 1997, p. 215. 

Lawrence JR, Swerhone GD, Topp E, Korber DR, Neu TR, Wassenaar LI (2007) Structural and functional responses of river biofilm communities to the nonsteroidal anti-inflammatory diclofenac. Environ Toxicol Chem 26 573-582... 

Measurement of exoenzymatic activities is potentially useful in detecting the effects of toxicants on heterotrophic biofilm communities. Sensitivity and direct relationship with organic matter use and, therefore, microbial growth make extracellular enzyme activities a relevant tool to assess the toxicity of specific compounds. Use of novel approaches that combine enzymatic and microscopic tools (e.g. ELF-phosphatase) may be extremely useful to detect anomalies at the sub-cellular scale. 

Figure 8.1. Biofilms are microbial communities that are made up of several species and often possess a distinct spatial structure. It has been found that living in a biofilm can offer significant protection to individuals, with sterilisation agents and even antibiotics being less potent against individuals if they are found in a biofilm. This is significant because it has been estimated that nearly three quarters of bacterial infections involve microbes that live in biofilm communities. Although there is a growing literature on the effects of NPs on biofilms, there is currently little knowledge of the production and metabolism of NPs in biofilms.

Caldwell, D. E. 1995. Cultivation and study of biofilm communities. In Microbial Biofilms (H. Lappin-Scott and J. W. Costerton, Eds.), Plant and Microbial Biotechnology Research Series 5, pp. 64-79. Cambridge Univ. Press, Cambridge, UK. 

Biofilm samples collected from carbon steel and concrete pipes of the DWSS Yovkovtsy had different appearance, content of water, organic and corrosion products, while ones from concrete pipe and water tank s surfaces were the same. Biofilm community mainly consisted of heterotrophic bacteria and some fungi, actinomyces and autotrophic bacteria. Corrosion related bacteria were determined in some of the biofilm samples. 

Haack, T.K. and McFeters, G.A., 1982, Nutritional relationships among microorganisms in an epilithic biofilm community. Microb. Ecol. 8 115 - 126. 

Biofilms can form on just about any imaginable surface metals, plastics, natural materials (such as rocks), medical implants, kitchen coimters, contact lenses, the walls of a hot tub or swimming pool, hmnan and animal tissue, etc. Indeed, wherever the combination of moisture, nutrients, and a surface exists, biofilms will likely be foimd as well. Biofilms are characterized by structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of pol)uneric substances. Biofilms are an important link in the energy budget of many natural commimities. Both types of cells produce a pol)uneric extracellular slime layer which encloses the cells. This complex aggregate of cells and polysaccharide is the biofilm community. 

Kanvillil N, Kurisseiy S. Dynamics of grazing protozoa follow that of microalgae in natural biofilm communities. Hydrobiologia 2013 718(1) 93-107. 

Here, we discuss an optimized DNA extraction method specifically for electrode-adhered biofilm communities. We describe the use of a biofilm DNA extraction kit from MoBio Laboratories Inc. to extract DNA from electrode-adhered communities (PowerBiofilm DNA Isolation Kit, www.mobio.com). Here, we included a slightly modified alternative for cell lysis to include less meehanical bead-beating and multiple heat treatments. This method for cell lysis has been found to be successful for electrogenic community analyses [18, 21], We do not endorse MoBio Laboratories. This protocol is solely meant to be a starting point for researchers. 

Evidence is accumulating that the the process of attachment to surfaces and growth in a biofilms is associated with the activation and repression of genes, resulting in a biofilm-specific phenotype of the microorganisms within a biofilm community. It is assumed that this process includes the expression of a biocide-resistant phenotype in all or a subset of the biofilm cells (Mah and O Toole, 2001). Induction of this phenotype may be caused by nutrient limitation, environmental stress, exposure to sublethal amounts of biocides, high cell density or a combination of these factors. 

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