{"id":1213,"date":"2017-01-18T19:49:11","date_gmt":"2017-01-18T19:49:11","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=1213"},"modified":"2024-04-25T18:45:19","modified_gmt":"2024-04-25T18:45:19","slug":"prokaryotic-biofilms","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/prokaryotic-biofilms\/","title":{"raw":"Prokaryotic Biofilms","rendered":"Prokaryotic Biofilms"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Discuss why prokaryotes often form biofilms<\/li>\r\n<\/ul>\r\n<\/div>\r\n\r\n[caption id=\"attachment_1247\" align=\"alignright\" width=\"399\"]<img class=\" wp-image-1247\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18194543\/800px-Biofilm_sur_eauPortAuray.jpg\" alt=\"photograph of a river with a filmy grey layer on its surface\" width=\"399\" height=\"219\" \/> Figure 1. A biofilm on the surface of the water in the on the edge of the Port of Saint-Goustan in Auray[\/caption]\r\n\r\nSome prokaryotes may be unculturable because they require the presence of other prokaryotic species. Until a couple of decades ago, microbiologists used to think of prokaryotes as isolated entities living apart. This model, however, does not reflect the true ecology of prokaryotes, most of which prefer to live in communities where they can interact. As we have seen, a\u00a0<span id=\"term850\" data-type=\"term\">biofilm<\/span>\u00a0is a microbial community (Figure 2) held together in a gummy-textured matrix that consists primarily of polysaccharides secreted by the organisms, together with some proteins and nucleic acids. Biofilms typically grow attached to surfaces. Some of the best-studied biofilms are composed of prokaryotes, although fungal biofilms have also been described, as well as some composed of a mixture of fungi and bacteria.\r\n<p id=\"fs-idp47328816\">Biofilms are present almost everywhere: they can cause the clogging of pipes and readily colonize surfaces in industrial settings. In recent, large-scale outbreaks of bacterial contamination of food, biofilms have played a major role. They also colonize household surfaces, such as kitchen counters, cutting boards, sinks, and toilets, as well as places on the human body, such as the surfaces of our teeth.<\/p>\r\n<p id=\"fs-idp56438336\">Interactions among the organisms that populate a biofilm, together with their protective\u00a0<em data-effect=\"italics\">exopolysaccharidic (EPS)<\/em>\u00a0environment, make these communities more robust than free-living, or planktonic, prokaryotes. The sticky substance that holds bacteria together also excludes most antibiotics and disinfectants, making biofilm bacteria hardier than their planktonic counterparts. Overall, biofilms are very difficult to destroy because they are resistant to many common forms of sterilization.<\/p>\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nThere are five stage of biofilm development:\r\n\r\n[caption id=\"attachment_1248\" align=\"aligncenter\" width=\"725\"]<img class=\"wp-image-1248 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18194728\/Figure_22_01_07.png\" alt=\"During the first stage of biofilm development, a few bacteria adhere to a surface. During stage 2, the bacteria grow hairy appendages called pili. During stage 3, the microfilm grows into lumpy colonies. In stage 4, the microfilm grows into a more ball-like shape that is anchored to the surface by a smaller clump of bacteria. In stage 5, the ball of bacteria is larger, and bacteria with flagella swim away.\" width=\"725\" height=\"450\" \/> Figure 2. Five stages of biofilm development are shown. Micrographs of a <em>Pseudomonas aeruginosabiofilm<\/em> in each of the stages of development are shown. (credit: D. Davis, Don Monroe, PLoS)[\/caption]\r\n\r\n&nbsp;\r\n<ul>\r\n \t<li>During stage 1, initial attachment, bacteria adhere to a solid surface via weak van der Waals interactions.<\/li>\r\n \t<li>During stage 2, irreversible attachment, hairlike appendages called pili permanently anchor the bacteria to the surface.<\/li>\r\n \t<li>During stage 3, maturation I, the biofilm grows through cell division and recruitment of other bacteria. An extracellular matrix composed primarily of polysaccharides holds the biofilm together.<\/li>\r\n \t<li>During stage 4, maturation II, the biofilm continues to grow and takes on a more complex shape.<\/li>\r\n \t<li>During stage 5, dispersal, the biofilm matrix is partly broken down, allowing some bacteria to escape and colonize another surface.<\/li>\r\n<\/ul>\r\nCompared to free-floating bacteria, bacteria in biofilms often show increased resistance to antibiotics and detergents. Why do you think this might be the case?\r\n\r\n[practice-area rows=\"4\"][\/practice-area]\r\n[reveal-answer q=\"805834\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"805834\"]The extracellular matrix and outer layer of cells protects the inner bacteria. The close proximity of cells also facilitates lateral gene transfer, a process by which genes such as antibiotic resistance genes are transferred from one bacterium to another. And even if lateral gene transfer does not occur, one bacterium that produces an exo-enzyme that destroys antibiotic may save neighboring bacteria.[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/5560245a-8b31-41b8-b4df-ce48704cab2e\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Discuss why prokaryotes often form biofilms<\/li>\n<\/ul>\n<\/div>\n<div id=\"attachment_1247\" style=\"width: 409px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1247\" class=\"wp-image-1247\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18194543\/800px-Biofilm_sur_eauPortAuray.jpg\" alt=\"photograph of a river with a filmy grey layer on its surface\" width=\"399\" height=\"219\" \/><\/p>\n<p id=\"caption-attachment-1247\" class=\"wp-caption-text\">Figure 1. A biofilm on the surface of the water in the on the edge of the Port of Saint-Goustan in Auray<\/p>\n<\/div>\n<p>Some prokaryotes may be unculturable because they require the presence of other prokaryotic species. Until a couple of decades ago, microbiologists used to think of prokaryotes as isolated entities living apart. This model, however, does not reflect the true ecology of prokaryotes, most of which prefer to live in communities where they can interact. As we have seen, a\u00a0<span id=\"term850\" data-type=\"term\">biofilm<\/span>\u00a0is a microbial community (Figure 2) held together in a gummy-textured matrix that consists primarily of polysaccharides secreted by the organisms, together with some proteins and nucleic acids. Biofilms typically grow attached to surfaces. Some of the best-studied biofilms are composed of prokaryotes, although fungal biofilms have also been described, as well as some composed of a mixture of fungi and bacteria.<\/p>\n<p id=\"fs-idp47328816\">Biofilms are present almost everywhere: they can cause the clogging of pipes and readily colonize surfaces in industrial settings. In recent, large-scale outbreaks of bacterial contamination of food, biofilms have played a major role. They also colonize household surfaces, such as kitchen counters, cutting boards, sinks, and toilets, as well as places on the human body, such as the surfaces of our teeth.<\/p>\n<p id=\"fs-idp56438336\">Interactions among the organisms that populate a biofilm, together with their protective\u00a0<em data-effect=\"italics\">exopolysaccharidic (EPS)<\/em>\u00a0environment, make these communities more robust than free-living, or planktonic, prokaryotes. The sticky substance that holds bacteria together also excludes most antibiotics and disinfectants, making biofilm bacteria hardier than their planktonic counterparts. Overall, biofilms are very difficult to destroy because they are resistant to many common forms of sterilization.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>There are five stage of biofilm development:<\/p>\n<div id=\"attachment_1248\" style=\"width: 735px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1248\" class=\"wp-image-1248 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18194728\/Figure_22_01_07.png\" alt=\"During the first stage of biofilm development, a few bacteria adhere to a surface. During stage 2, the bacteria grow hairy appendages called pili. During stage 3, the microfilm grows into lumpy colonies. In stage 4, the microfilm grows into a more ball-like shape that is anchored to the surface by a smaller clump of bacteria. In stage 5, the ball of bacteria is larger, and bacteria with flagella swim away.\" width=\"725\" height=\"450\" \/><\/p>\n<p id=\"caption-attachment-1248\" class=\"wp-caption-text\">Figure 2. Five stages of biofilm development are shown. Micrographs of a <em>Pseudomonas aeruginosabiofilm<\/em> in each of the stages of development are shown. (credit: D. Davis, Don Monroe, PLoS)<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<ul>\n<li>During stage 1, initial attachment, bacteria adhere to a solid surface via weak van der Waals interactions.<\/li>\n<li>During stage 2, irreversible attachment, hairlike appendages called pili permanently anchor the bacteria to the surface.<\/li>\n<li>During stage 3, maturation I, the biofilm grows through cell division and recruitment of other bacteria. An extracellular matrix composed primarily of polysaccharides holds the biofilm together.<\/li>\n<li>During stage 4, maturation II, the biofilm continues to grow and takes on a more complex shape.<\/li>\n<li>During stage 5, dispersal, the biofilm matrix is partly broken down, allowing some bacteria to escape and colonize another surface.<\/li>\n<\/ul>\n<p>Compared to free-floating bacteria, bacteria in biofilms often show increased resistance to antibiotics and detergents. Why do you think this might be the case?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"4\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q805834\">Show Answer<\/span><\/p>\n<div id=\"q805834\" class=\"hidden-answer\" style=\"display: none\">The extracellular matrix and outer layer of cells protects the inner bacteria. The close proximity of cells also facilitates lateral gene transfer, a process by which genes such as antibiotic resistance genes are transferred from one bacterium to another. And even if lateral gene transfer does not occur, one bacterium that produces an exo-enzyme that destroys antibiotic may save neighboring bacteria.<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_5560245a-8b31-41b8-b4df-ce48704cab2e\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/5560245a-8b31-41b8-b4df-ce48704cab2e?iframe_resize_id=assessment_practice_id_5560245a-8b31-41b8-b4df-ce48704cab2e\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-1213\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><li>Biofilm sur eauPortAuray. <strong>Authored by<\/strong>: F.Lamiot. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Biofilm_sur_eauPortAuray.jpg\">https:\/\/commons.wikimedia.org\/wiki\/File:Biofilm_sur_eauPortAuray.jpg<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/\">CC BY-SA: Attribution-ShareAlike<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"},{\"type\":\"cc\",\"description\":\"Biofilm sur eauPortAuray\",\"author\":\"F.Lamiot\",\"organization\":\"\",\"url\":\"https:\/\/commons.wikimedia.org\/wiki\/File:Biofilm_sur_eauPortAuray.jpg\",\"project\":\"\",\"license\":\"cc-by-sa\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"51ab1c86-f92a-425c-8706-93d1cdedba4e, 7a3b9528-3771-43c9-831b-40327f13885d","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1213","chapter","type-chapter","status-publish","hentry"],"part":1195,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1213","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":12,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1213\/revisions"}],"predecessor-version":[{"id":8296,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1213\/revisions\/8296"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/1195"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1213\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=1213"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=1213"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=1213"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=1213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}