Artykuły w czasopismach: „Extracellular Bacterial Polysaccharides (ECP)”

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Atabek, Arzu, i Terri A. Camesano. "Atomic Force Microscopy Study of the Effect of Lipopolysaccharides and Extracellular Polymers on Adhesion of Pseudomonas aeruginosa". Journal of Bacteriology 189, nr 23 (28.09.2007): 8503–9. http://dx.doi.org/10.1128/jb.00769-07.

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ABSTRACT The roles of lipopolysaccharides (LPS) and extracellular polymers (ECP) on the adhesion of Pseudomonas aeruginosa PAO1 (expresses the A-band and B-band of O antigen) and AK1401 (expresses the A-band but not the B-band) to silicon were investigated with atomic force microscopy (AFM) and related to biopolymer physical properties. Measurement of macroscopic properties showed that strain AK1401 is more negatively charged and slightly more hydrophobic than strain PAO1 is. Microscopic AFM investigations of individual bacteria showed differences in how the biopolymers interacted with silicon. PAO1 showed larger decay lengths in AFM approach cycles, suggesting that the longer polymers on PAO1 caused greater steric repulsion with the AFM tip. For both bacterial strains, the long-range interactions we observed (hundreds of nanometers) were inconsistent with the small sizes of LPS, suggesting that they were also influenced by ECP, especially polysaccharides. The AFM retraction profiles provide information on the adhesion strength of the biopolymers to silicon (F adh). For AK1401, the adhesion forces were only slightly lower (F adh = 0.51 nN compared to 0.56 nN for PAO1), but the adhesion events were concentrated over shorter distances. More than 90% of adhesion events for AK1401 were at distances of <600 nm, while >50% of adhesion events for PAO1 were at distances of >600 nm. The sizes of the observed molecules suggest that the adhesion of P. aeruginosa to silicon was controlled by ECP, in addition to LPS. Steric and electrostatic forces each contributed to the interfacial interactions between P. aeruginosa and the silicon surface.

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Whitfield, Chris. "Bacterial extracellular polysaccharides". Canadian Journal of Microbiology 34, nr 4 (1.04.1988): 415–20. http://dx.doi.org/10.1139/m88-073.

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The synthesis of extracellular polysaccharides has been recognized in certain bacterial cultures since the 1880s. It is now apparent that a wide range of bacteria produce these polymers and an equally wide range of chemical structures are possible. Their surface location, together with the range of available monosaccharide combinations, noncarbohydrate substituents, and linkage types, make extracellular polysaccharides excellent agents of diversity. As a result, much effort has been directed towards elucidating their structure in pathogenic bacteria and in enteric organisms in particular. Commercial applications of microbial polysaccharides have now broadened the scope of structural information. Most recently, technological advances in molecular biology have created the possibility of manipulating desired polymer characteristics, and with these advances, our knowledge of the mechanisms of synthesis and regulation of cell surface polysaccharides has improved. Ultimately more information regarding the function of extracellular polysaccharides in natural environments may result.

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Dignac, M. F., V. Urbain, D. Rybacki, A. Bruchet, D. Snidaro i P. Scribe. "Chemical description of extracellular polymers: implication on activated sludge floc structure". Water Science and Technology 38, nr 8-9 (1.10.1998): 45–53. http://dx.doi.org/10.2166/wst.1998.0789.

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Activated sludge extracellular polymers (ECP) were extracted either by sonication or a combination of sonication and cation exchange resin treatment (CER). The chemical composition of the aqueous extract was investigated by chromatographic analysis of amino acids and sugars after hydrolysis. Up to 70 to 80% of the total organic carbon (TOC) of ECP was characterized. Proteins were found to be the major constituent of ECP, which was confirmed by pyrolysis/GC/MS analysis. Sugar and protein analysis led to complementary information both on the origin of extracellular material and on sludge floc structure. The monosaccharide composition in ECP and sludge allowed the proposal of different origins for extracellular polysaccharides. The predominance of proteins in ECP underlined their key role in the floc structure, and led to hypotheses on their origin. Proteins were better extracted than sugars when the CER extraction was combined with sonication. This supposed that proteins are more involved than sugars in electrostatic bonds with multivalent cations. Electrostatic bonds were found to be uniformly distributed in the floc and closely combined with hydrophobic bonds. About 25% of ECP amino acids were negatively charged and 24% exhibited hydrophobic properties, highlighting the specific role of proteins in the floc structure.

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Rockey, D. D., P. S. D. Turaga, G. D. Wiens, B. A. Cook i S. L. Kaattari. "Serine proteinase of Renibacterium salmoninarum digests a major autologous extracellular and cell-surface protein". Canadian Journal of Microbiology 37, nr 10 (1.10.1991): 758–63. http://dx.doi.org/10.1139/m91-130.

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Renibacterium salmoninarum is a pathogen of salmonid fish that produces large amounts of extracellular protein (ECP) during growth. A proteolytic activity present in ECP at elevated temperatures digested the majority of the proteins in ECP. This digestion was also associated with the loss of ECP immunosuppressive function. In vitro activity of the proteinase in ECP was temperature dependent: it was not detected in an 18-h digest at 4 and 17 °C but became readily apparent at 37 °C. Proteinase activity was detected at bacterial physiological temperatures (17 °C) in reactions incubated for several days. Under these conditions, digestion of partially purified p57, a major constituent of ECP and a major cell-surface protein, yielded a spectrum of breakdown products similar in molecular weight and antigenicity to those in ECP. This pattern of digestion suggests that most of the immunologically related constituents of ECP are p57 and its breakdown products. The proteolytic activity was sensitive to phenylmethylsulfonyl fluoride, methanol, and ethanol and to 10-min incubation at temperatures above 65 °C. Electrophoretic analysis of the proteinase on polyacrylamide gels containing proteinase substrates indicated the native form to be 100 kDa or greater. The enzyme was active against selected unrelated substrates only when coincubated with a denaturant (0.1% lauryl sulfate) and (or) a reducing agent (20 mM dithiothreitol). Key words: Renibacterium salmoninarum, proteinase, hemagglutinin, antigen F, bacterial kidney disease.

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Bandin, I., Y. Santos, D. W. Bruno, R. S. Raynard, A. E. Toranzo i J. L. Barja. "Lack of Biological Activities in the Extracellular Products of Renibacterium salmoninarum". Canadian Journal of Fisheries and Aquatic Sciences 48, nr 3 (1.03.1991): 421–25. http://dx.doi.org/10.1139/f91-054.

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Evaluation in vivo and in vitro of the extracellular products (ECP) of a group of Renibacterium salmoninarum strains from different geographic origins revealed a low production of extracellular proteins in all strains and confirmed that most of the isolates were poor producers of proteolytic enzymes. The ECP displayed neither haemolytic activity nor capacity to alter the osmotic equilibrium of fish erythrocytes. In addition, none of the ECP samples displayed cytotoxic activities regardless of the origin of the cell line employed and did not contain substances lethal for fish, since no mortalities were recorded when doses ranging from 10 to 20 μg protein/g fish were administered. Although the present work failed to demonstrate toxicity in vivo of the ECP, it is possible that some extracellular enzymes contribute to the weakening of fish during the disease process and allow bacterial survival.

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Huang, C. Y., P. C. Liu i K. K. Lee. "Withering Syndrome of the Small Abalone, Haliotis diversicolor supertexta, Is Caused by Vibrio parahaemolyticus and Associated with Thermal Induction". Zeitschrift für Naturforschung C 56, nr 9-10 (1.10.2001): 898–901. http://dx.doi.org/10.1515/znc-2001-9-1036.

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Abstract The susceptibility of the small abalone Haliotis diversicolor supertexta to Vibrio parahaemolyticus 880915 strain and its extracellular products (ECP) at different temperatures was investigated. The strain was previously isolated from the haemolymph of the moribund small abalone with withering syndrome during an outbreak of mass mortality among the cultured animals in September 1999 in I-Lan, Taiwan. The bacterium and its ECP were lethal to the small abalone. Onset of the withering syndrome in the moribund or dead animals could be observed at 4 -7 d post-bacterial challenge. The same bacterial strain could be isolated from the haemolymph of the moribund animals with or without the syndrome post-bacterial challenge. This syndrome could not be observed in the moribund or dead animals post-ECP challenge. The animals were more susceptible to the bacterium and ECP challenge at higher temperature (28 °C) indicating that the outbreak of the disease in warmer season is associated with thermal induction.

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Vu, Barbara, Miao Chen, Russell Crawford i Elena Ivanova. "Bacterial Extracellular Polysaccharides Involved in Biofilm Formation". Molecules 14, nr 7 (13.07.2009): 2535–54. http://dx.doi.org/10.3390/molecules14072535.

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Soliman, Caroline, Gerald B. Pier i Paul A. Ramsland. "Antibody recognition of bacterial surfaces and extracellular polysaccharides". Current Opinion in Structural Biology 62 (czerwiec 2020): 48–55. http://dx.doi.org/10.1016/j.sbi.2019.12.001.

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kumari, G. Sindhu, R. Rajila, S. Sujithra, M. Jenifer Tamizharasi, D. Beula shiny i T. Kumaran. "Haemagglutinin And Chitinase Activities Of Virulent Aeromonas Hydrophila Islolated From Cyprinus Carpio". Journal of Community Pharmacy Practice, nr 11 (28.08.2021): 4–8. http://dx.doi.org/10.55529/jcpp11.4.8.

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In the present study the Hemeagglutination and Chitinolytic activity of extracellular products (ECP) secreted from Aeromonas hydrophila were examined. The present study showed infectivity experiments, incomplete creation of extracellular products and chitinase activity of the A. hydrophila. In haemagglutination assay in the present experiment, bacterial agglutination takes place in 1:1, 1:2, 1:4, 1:8,1:16,1:32 dilutions in the E.S-2 treated O blood groups and in 1:1,1:4 where as the ES -1and ES-3 failed to agglutinate. Generally, whole cells showed a wider range of enzymic activities than ECP. The results showed that extra cellular product chitin could be a promising source for pathogenic factor in microorganisms.

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Eriksson, L., i B. Alm. "Study of Flocculation Mechanisms by Observing Effects of a Complexing Agent on Activated Sludge Properties". Water Science and Technology 24, nr 7 (1.10.1991): 21–28. http://dx.doi.org/10.2166/wst.1991.0180.

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Electrostatic interactions between bacterial surfaces, extracellular polymers (ECP) and polyvalent metal ions are important in activated sludge flocculation. An indirect study of these mechanisms was done by adding different concentrations of EDTA to activated sludge samples from 6 Swedish wastewater treatment plants. The effects on sludge properties were studied with sedimentation and filtration tests as well as analysis of released extracellular polymers. EDTA had a significant effect on sedimentation velocity in all investigated sludges. This shows that charged polymers are important for the properties of the floc surfaces and in building up the sludge macroflocs. The effect on filtration resistance where the bulk properties of the primary flocs are more important varied considerably for the different sludges. Thus, both electrostatic and other interactions are involved to a varying extent in building up the primary flocs in the sludges investigated. Variations in sedimentation velocity, residual turbidity, filtration resistance and release of ECP with variations in EDTA concentrations could be explained by effects of polyvalent metal ions on ECP binding and conformation.

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Stefani, E., i P. Medeghini Bonatti. "Ultrastructure in Bean Leaves Infiltrated with Bacterial Extracellular Polysaccharides". Journal of Phytopathology 137, nr 3 (marzec 1993): 195–206. http://dx.doi.org/10.1111/j.1439-0434.1993.tb01339.x.

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Suhermanto, Achmad, Sukenda Sukenda, Muhammad Zairin Jr., Angela Mariana Lusiastuti i Sri Nuryati. "TOKSISITAS SEL UTUH DAN EXTRACELLULAR PRODUCT (ECP) Streptococcus agalactiae β-HEMOLITIK DAN NON-HEMOLITIK PADA IKAN NILA (Oreochromis niloticus)". Jurnal Riset Akuakultur 13, nr 4 (23.05.2019): 317. http://dx.doi.org/10.15578/jra.13.4.2018.317-328.

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Bakteri Streptococcus agalactiae tipe β-hemolitik dan non-hemolitik menjadi agen penyebab infeksi streptococcosis yang mengakibatkan kematian dan kerugian besar pada budidaya ikan nila. Penelitian ini bertujuan untuk membandingkan toksisitas sel utuh dan extracellular product (ECP) bakteri b-hemolitik dan non-hemolitik yang diinjeksikan pada ikan nila. Karakterisasi S. agalactiae berdasarkan SNI dan API 20 STREP, serta pemisahan protein dengan metode SDS-PAGE. Pengujian toksisitas dilakukan dengan cara menginjeksikan sel utuh dan ECP S. agalactiae secara intraperitoneal (IP) dengan dosis 0,1 mL ekor-1. Hasil uji biokimia, dan konfirmasi dengan API 20 STREP menunjukkan bahwa semua isolat positif S. agalactiae. Fraksinasi protein pada sel utuh bakteri diperoleh pita protein masing-masing sebanyak sembilan dan tujuh pita pada tipe β-hemolitik dan non-hemolitik. Fraksinasi ECP teridentifikasi pada β-hemolitik sebanyak tujuh pita dan non-hemolitik empat pita protein. Konsentrasi protein sel utuh dan ECP b-hemolitik lebih besar dibandingkan bakteri non-hemolitik. Gejala abnormalitas lebih cepat terjadi pada ikan nila yang diinjeksi ECP bakteri b-hemolitik dan berbanding lurus dengan kematian sebanyak 91%-100% pada jam ke-13 pascainjeksi. Hasil ini menunjukkan bahwa ECP bakteri S. agalactiae β-hemolitik lebih virulen dibandingkan tipe non-hemolitik. Hingga akhir pemeliharaan tidak ada kematian pada ikan yang diinjeksi sel utuh bakteri S. agalactiae b-hemolitik dan non-hemolitik. Studi histopatologi ikan yang diinjeksi ECP S. agalactiae pada organ hati, limpa, otak, dan ginjal menunjukkan adanya kongesti, hemoragi, dan nekrosis.The β-hemolytic and non-hemolytic biotype of Streptococcus agalactiae are the agents that cause streptococcosis infection which resulted in high mortality and major losses in tilapia culture. This study aimed to compare the toxicity of whole cell and extracellular product (ECP) b-hemolytic and non-hemolytic bacteria from injected tilapia. Characterization of S. agalactiae was based on SNI and API 20 STREP and protein separation by SDS-PAGE method. Toxicity test was carried out by injecting whole cells and ECP S. agalactiae intraperitoneally with a dose of 0.1 mL fish-1. The results of biochemical tests, with confirmation by API 20 STREP showed that all isolates were positive for S. agalactiae. Protein fractionation of whole bacterial cells obtained as many as nine and seven bands of protein in b-hemolytic and non hemolytic biotype, respectively. ECP fractionation was identified in β-hemolytic biotype as many as seven bands and four protein bands in non-hemolytic. The whole cell protein concentration and ECP β-hemolytic were higher than non-hemolytic bacteria. Symptoms of abnormalities occurred faster in tilapia which was injected with ECP b-hemolytic bacteria and had positive correlation with 91%-100% mortalities at the 13th hours post-injection. This results indicated that ECP of S. agalactiae β-hemolytic are more virulent than non-hemolytic. Until the end of the trial, there were no deaths in fish injected with whole cells of b-hemolytic and non-hemolytic S. agalactiae. Histopathological studies of ECP-injected fish S. agalactiae in the liver, spleen, brain, and kidneys showed congestion, hemorrhage, and necrosis.

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Walkes, C. M., i L. W. O 'Garro. "Role of extracellular polysaccharides fromXanthomonas campestrispv.vesicatoriain bacterial spot of pepper". Physiological and Molecular Plant Pathology 48, nr 2 (luty 1996): 91–104. http://dx.doi.org/10.1006/pmpp.1996.0009.

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Bianciotto, Valeria, Silvia Andreotti, Raffaella Balestrini, Paola Bonfante i Silvia Perotto. "Mucoid Mutants of the Biocontrol Strain Pseudomonas fluorescens CHA0 Show Increased Ability in Biofilm Formation on Mycorrhizal and Nonmycorrhizal Carrot Roots". Molecular Plant-Microbe Interactions® 14, nr 2 (luty 2001): 255–60. http://dx.doi.org/10.1094/mpmi.2001.14.2.255.

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Extracellular polysaccharides play an important role in the formation of bacterial biofilms. We tested the biofilmforming ability of two mutant strains with increased production of acidic extracellular polysaccharides compared with the wild-type biocontrol strain Pseudomonas fluorescens CHA0. The anchoring of bacteria to axenic nonmycorrhizal and mycorrhizal roots as well as on extraradical mycelium of the arbuscular mycorrhizal fungus Glomus intraradices was investigated. The nonmucoid wild-type strain P. fluorescens CHA0 adhered very little on all surfaces, whereas both mucoid strains formed a dense and patchy bacterial layer on the roots and fungal structures. Increased adhesive properties of plant-growth-promoting bacteria may lead to more stable interactions in mixed inocula and the rhizosphere.

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Piontek, J., M. Lunau, N. Händel, C. Borchard, M. Wurst i A. Engel. "Acidification increases microbial polysaccharide degradation in the ocean". Biogeosciences Discussions 6, nr 6 (2.12.2009): 11377–400. http://dx.doi.org/10.5194/bgd-6-11377-2009.

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Abstract. With the accumulation of anthropogenic carbon dioxide (CO2), a proceeding decline in seawater pH has been induced that is referred to as ocean acidification. The ocean's capacity for CO2 storage is strongly affected by biological processes, whose feedback potential is difficult to evaluate. The main source of CO2 in the ocean is the decomposition and subsequent respiration of organic molecules by heterotrophic bacteria. However, very little is known about potential effects of ocean acidification on bacterial degradation activity. This study reveals that the degradation of polysaccharides, a major component of marine organic matter, by bacterial extracellular enzymes was significantly accelerated during experimental simulation of ocean acidification. Results were obtained from pH perturbation experiments, where rates of extracellular α- and β-glucosidase were measured and the loss of neutral and acidic sugars from phytoplankton-derived polysaccharides was determined. Our study suggests that a faster bacterial turnover of polysaccharides at lowered ocean pH has the potential to affect the cycling of organic carbon in the future ocean by weakening the biological carbon pump and increasing the respiratory production of CO2.

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Piontek, J., M. Lunau, N. Händel, C. Borchard, M. Wurst i A. Engel. "Acidification increases microbial polysaccharide degradation in the ocean". Biogeosciences 7, nr 5 (19.05.2010): 1615–24. http://dx.doi.org/10.5194/bg-7-1615-2010.

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Abstract. With the accumulation of anthropogenic carbon dioxide (CO2), a proceeding decline in seawater pH has been induced that is referred to as ocean acidification. The ocean's capacity for CO2 storage is strongly affected by biological processes, whose feedback potential is difficult to evaluate. The main source of CO2 in the ocean is the decomposition and subsequent respiration of organic molecules by heterotrophic bacteria. However, very little is known about potential effects of ocean acidification on bacterial degradation activity. This study reveals that the degradation of polysaccharides, a major component of marine organic matter, by bacterial extracellular enzymes was significantly accelerated during experimental simulation of ocean acidification. Results were obtained from pH perturbation experiments, where rates of extracellular α- and β-glucosidase were measured and the loss of neutral and acidic sugars from phytoplankton-derived polysaccharides was determined. Our study suggests that a faster bacterial turnover of polysaccharides at lowered ocean pH has the potential to reduce carbon export and to enhance the respiratory CO2 production in the future ocean.

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Balducci, Evita, Francesco Papi, Daniela Eloisa Capialbi i Linda Del Bino. "Polysaccharides’ Structures and Functions in Biofilm Architecture of Antimicrobial-Resistant (AMR) Pathogens". International Journal of Molecular Sciences 24, nr 4 (17.02.2023): 4030. http://dx.doi.org/10.3390/ijms24044030.

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Bacteria and fungi have developed resistance to the existing therapies such as antibiotics and antifungal drugs, and multiple mechanisms are mediating this resistance. Among these, the formation of an extracellular matrix embedding different bacterial cells, called biofilm, is an effective strategy through which bacterial and fungal cells are establishing a relationship in a unique environment. The biofilm provides them the possibility to transfer genes conferring resistance, to prevent them from desiccation and to impede the penetration of antibiotics or antifungal drugs. Biofilms are formed of several constituents including extracellular DNA, proteins and polysaccharides. Depending on the bacteria, different polysaccharides form the biofilm matrix in different microorganisms, some of them involved in the first stage of cells’ attachment to surfaces and to each other, and some responsible for giving the biofilm structure resistance and stability. In this review, we describe the structure and the role of different polysaccharides in bacterial and fungal biofilms, we revise the analytical methods to characterize them quantitatively and qualitatively and finally we provide an overview of potential new antimicrobial therapies able to inhibit biofilm formation by targeting exopolysaccharides.

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Sutherland, I. W. "Biosynthesis and Composition of Gram-Negative Bacterial Extracellular and Wall Polysaccharides". Annual Review of Microbiology 39, nr 1 (październik 1985): 243–70. http://dx.doi.org/10.1146/annurev.mi.39.100185.001331.

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Leriche, V., P. Sibille i B. Carpentier. "Use of an Enzyme-Linked Lectinsorbent Assay To Monitor the Shift in Polysaccharide Composition in Bacterial Biofilms". Applied and Environmental Microbiology 66, nr 5 (1.05.2000): 1851–56. http://dx.doi.org/10.1128/aem.66.5.1851-1856.2000.

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ABSTRACT An enzyme-linked lectinsorbent assay (ELLA) was developed for quantification and characterization of extracellular polysaccharides produced by 1- and 4-day biofilms of 10 bacterial strains isolated from food industry premises. Peroxidase-labeled concanavalin A (ConA) and wheat germ agglutinin (WGA) were used, as they specifically bind to saccharide residues most frequently encountered in biofilms matrices:d-glucose or d-mannose for ConA andN-acetyl-d-glucosamine orN-acetylneuraminic acid for WGA. The ELLA applied to 1- and 4-day biofilms colonizing wells of microtiter plates was able to detect that for Stenotrophomonas maltophilia and to a lesser extent Staphylococcus sciuri, the increase in production of exopolysaccharides over time was not the same for sugars binding with ConA and those binding with WGA. Differences in extracellular polysaccharides produced were observed among strains belonging to the same species. These results demonstrate that ELLA is a useful tool not only for rapid characterization of biofilm extracellular polysaccharides but also, in studies of individual strains, for detection of changes over time in the proportion of the exopolysaccharidic component within the polymeric matrix.

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Decker, Eva-Maria, Ilka Dietrich, Christian Klein i Christiane von Ohle. "Dynamic Production of Soluble Extracellular Polysaccharides byStreptococcus mutans". International Journal of Dentistry 2011 (2011): 1–6. http://dx.doi.org/10.1155/2011/435830.

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Caries development in the presence ofStreptococcus mutansis associated not only with the production of extracellular water-insoluble polymers but also is based on water-soluble polysaccharides. The aim of this study was the evaluation of a novel glucan-specific Lectin assay for monitoring water-soluble EPS produced byS. mutansduring several growth periods in different media.S. mutanscultures were grown for 24 h, 48 h, and 144 h in medium deficient of sucrose (A) and medium supplemented with 5% sucrose (B). Microtiter well plates were coated with cell-free supernatants followed by the addition of labeled Concanavalin-A and enzyme substrate. The substrate reactions were kinetically detected at 405 nm. The validation of the assay was performed using carbohydrates dextran, xanthan, and sucrose as reference. This new Concanavalin-A-based assay showed the highest sensitivity for dextran and revealed that the glucan production ofS. mutansreached its maximum at 144 h in medium B according to bacterial maturation.

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Gieroba, Barbara, Mikolaj Krysa, Kinga Wojtowicz, Adrian Wiater, Małgorzata Pleszczyńska, Michał Tomczyk i Anna Sroka-Bartnicka. "The FT-IR and Raman Spectroscopies as Tools for Biofilm Characterization Created by Cariogenic Streptococci". International Journal of Molecular Sciences 21, nr 11 (27.05.2020): 3811. http://dx.doi.org/10.3390/ijms21113811.

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Fourier transform infrared (FT-IR) and Raman spectroscopy and mapping were applied to the analysis of biofilms produced by bacteria of the genus Streptococcus. Bacterial biofilm, also called dental plaque, is the main cause of periodontal disease and tooth decay. It consists of a complex microbial community embedded in an extracellular matrix composed of highly hydrated extracellular polymeric substances and is a combination of salivary and bacterial proteins, lipids, polysaccharides, nucleic acids, and inorganic ions. This study confirms the value of Raman and FT-IR spectroscopies in biology, medicine, and pharmacy as effective tools for bacterial product characterization.

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Morris, V. J., i M. J. Miles. "Effect of natural modifications on the functional properties of extracellular bacterial polysaccharides". International Journal of Biological Macromolecules 8, nr 6 (grudzień 1986): 342–48. http://dx.doi.org/10.1016/0141-8130(86)90053-x.

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Sapunova, L. I., A. G. Lobanok, K. K. Yatsevich, S. A. Kulish, I. A. Tamkovich, L. V. Yarkhova i Ya M. Sysaliatsin. "Screening, characterization and molecular-genetical identification of a new bacterial strain Paenibacillus species". Doklady of the National Academy of Sciences of Belarus 63, nr 2 (18.05.2019): 181–88. http://dx.doi.org/10.29235/1561-8323-2019-63-2-181-188.

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Bacterial variant PS-K-17 was isolated from wheat grain contaminated by polysaccharide-producing microbiota for further characterization. It was found that the isolate grown on agar slants and in submerged culture on media with specific substrates synthesized beta-galactosidase, amylase, protease, pectinase, cellulase, beta-glucanase, lipase (esterase), alginase, extracellular polysaccharides, and pigments, probably carotenoids. Based on cultural-morphological and physiological-biochemical properties and phylogenetic analysis of nucleotide sequences of 16S rRNA gene (access code MF443394 in GenBank) the bacterial culture was identified as Paenibacillus species PS-K-17. The studied isolate forms one phylogenetic branch with type strains Paenibacillus nicotianae (98.3 %), Paenibacillus hordei (98.2 %), Paenibacillus kyungheensis (97.9 %), holding wherein a separate position. Strain Paenibacillus sp. PS-K-17 may find use in biotechnology as a producer of extracellular polysaccharides and enzymes splitting plant polymeric substances as well as a component of microbial consortium-ingredient of a new complex feed additive.

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Perera, Sumudu R., Akosiererem S. Sokaribo i Aaron P. White. "Polysaccharide Vaccines: A Perspective on Non-Typhoidal Salmonella". Polysaccharides 2, nr 3 (11.09.2021): 691–714. http://dx.doi.org/10.3390/polysaccharides2030042.

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Polysaccharides are often the most abundant antigens found on the extracellular surfaces of bacterial cells. These polysaccharides play key roles in interactions with the outside world, and for many bacterial pathogens, they represent what is presented to the human immune system. As a result, many vaccines have been or currently are being developed against carbohydrate antigens. In this review, we explore the diversity of capsular polysaccharides (CPS) in Salmonella and other selected bacterial species and explain the classification and function of CPS as vaccine antigens. Despite many vaccines being developed using carbohydrate antigens, the low immunogenicity and the diversity of infecting strains and serovars present an antigen formulation challenge to manufacturers. Vaccines tend to focus on common serovars or have changing formulations over time, reflecting the trends in human infection, which can be costly and time-consuming. We summarize the approaches to generate carbohydrate-based vaccines for Salmonella, describe vaccines that are in development and emphasize the need for an effective vaccine against non-typhoidal Salmonella strains.

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Mariana Peroni, Renzo Girardello, Ornella Pancheri, Stefano Bonvini i Giampietro Bertasi. "Hard-to-heal wounds: A new biofilm treatment with a novel desiccant". Magna Scientia Advanced Biology and Pharmacy 3, nr 1 (30.08.2021): 058–63. http://dx.doi.org/10.30574/msabp.2021.3.1.0036.

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Biofilms are slow-growing communities of multiple strains of bacteria that resist both innate immune mechanisms as well as antibiotics [1] [16] [17]. They also contain extracellular DNA (bacterial or host origin), polysaccharides, and proteins that form dense matrix is resistant to the host’s innate immune response [18] [19].

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Clarke, Anthony J., Vivian Sarabia, Wendy Keenleyside, P. Ronald MacLachlan i Chris Whitfield. "The compositional analysis of bacterial extracellular polysaccharides by high-performance anion-exchange chromatography". Analytical Biochemistry 199, nr 1 (listopad 1991): 68–74. http://dx.doi.org/10.1016/0003-2697(91)90270-4.

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Janaki, V., Byung-Taek Oh, K. Vijayaraghavan, Jin-Won Kim, Seol Ah Kim, A. K. Ramasamy i Seralathan Kamala-Kannan. "Application of bacterial extracellular polysaccharides/polyaniline composite for the treatment of Remazol effluent". Carbohydrate Polymers 88, nr 3 (kwiecień 2012): 1002–8. http://dx.doi.org/10.1016/j.carbpol.2012.01.045.

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Van Doorn, W. G., F. Thiel i A. Boekestein. "Cryoscanning electron microscopy of a layer of extracellular polysaccharides produced by bacterial colonies". Scanning 12, nr 6 (listopad 1990): 297–99. http://dx.doi.org/10.1002/sca.4950120603.

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Spinola, Manuela S., Diego Figueiredo Nóbrega, Altair Antoninha Del Bel Cury, Antonio Pedro Ricomini Filho, Jaime Aparecido Cury i Livia Maria Andaló Tenuta. "Fluoride Penetration and Clearance Are Higher in Exopolysaccharide-Containing Bacterial Pellets". Caries Research 53, nr 1 (6.06.2018): 16–23. http://dx.doi.org/10.1159/000488596.

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Extracellular polysaccharides (EPS) could increase the penetration of fluoride through dental biofilm, reducing its cariogenicity. We measured the concentration of fluoride in EPS-containing (EPS+) or not-containing (EPS–) Streptococcus mutans bacterial pellets resembling test biofilms, before and up to 60 min after a 0.05% NaF rinse in situ. Fluoride penetration and clearance were higher in EPS+ bacterial pellets. The data suggest that EPS enhances fluoride penetration, but also accelerates fluoride clearance from dental biofilms.

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Khusainov, I. A., E. R. Yakubov, Z. A. Kanarskaya, A. V. Kanarskiy, I. A. Maximova i A. V. Kachalkin. "Efficiency of synthesis of extracellular polysaccharides strains of Lipomyces yeast". Proceedings of the Voronezh State University of Engineering Technologies 80, nr 4 (21.03.2019): 269–77. http://dx.doi.org/10.20914/2310-1202-2018-4-269-277.

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The formation of extracellular polysaccharides is a fairly well-studied property of bacteria that is used for the industrial production of such extracellular bacterial as xanthan, dextran, gellan, hyaluronan, etc.. Polysaccharides synthesized by fungi are also widely used, such as schizophillan and scleroglucan. However, polysaccharides synthesized by yeast and yeast-like fungi have not yet found wide industrial application, with the exception of pullulan produced by Aureobasidium pullulans yeast, although there are a number of promising developments in the use of yeast polysaccharides in medicine. Yeast synthesizes polymers that contain mannans, glucans, phosphomannans, galactomannans, and glucuronoxylmannans. Polysaccharides produced by different species, and sometimes even by different strains of the same species, may differ in chemical composition and structure. Such a variety of composition and properties opens up great prospects for their use in various fields: medicine, chemical, food and cosmetic industries, as well as feed additives. In this regard, the search for new producers of polysaccharides is very relevant. Yeast of the genus Lipomyces is found in the soils of the southern and northern hemispheres of the Earth, except in the high-mountainous regions and tundra soils, where soil formation processes are in early stages of development, but the soils are rich in steppe and forest zones. As a result of the research, it turns out that from the point of view of biomass growth on the presented nutrient medium at the temperatures studied, the strains of the Lipomyces lipofer yeast КБП Y-6267 and КБП Y-6265 attract the most attention, especially at low temperatures. With an increase in temperature, the increase in biomass in these yeasts decreases markedly. As producers of extracellular polysaccharide, it is worth noting the КБП Y-6267 and КБП Y-6264 strains at 20 °C and the КБП Y-6268 strains and the КБП Y-6234 at 30 °C, which indicates the possibility of using for these purposes different species of the genus Lipomyces. At 30 °C, Lipomyces lipofer strains of the КБП Y-6268 and Lipomyces kononenkoae КБП Y-6234 had the highest enzyme activities, however, there was no relationship between enzyme activities, biomass gains and polysaccharide yields at low temperatures.

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Dimopoulou, Maria, i Marguerite Dols-Lafargue. "Exopolysaccharides Producing Lactic Acid Bacteria in Wine and Other Fermented Beverages: For Better or for Worse?" Foods 10, nr 9 (17.09.2021): 2204. http://dx.doi.org/10.3390/foods10092204.

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Lactic acid bacteria (LAB) from fermented beverages such as wine, cider and beer produce a wide range of exopolysaccharides (EPS) through multiple biosynthetic pathways. These extracellular polysaccharides constitute key elements for bacterial species adaptation to such anthropic processes. In the food industry, LAB polysaccharides have been widely studied for their rheological, functional and nutritional properties; however, these have been poorly studied in wine, beer and cider until recently. In this review, we have gathered the information available on these specific polysaccharide structure and, biosynthetic pathways, as well as the physiology of their production. The genes associated with EPS synthesis are also presented and compared. Finally, the possible role of EPS for bacterial survival and spread, as well as the risks or possible benefits for the winemaker and the wine lover, are discussed.

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Boher, B., M. Nicole, M. Potin i J. P. Geiger. "Extracellular Polysaccharides from Xanthomonas axonopodis pv. manihotis Interact with Cassava Cell Walls During Pathogenesis". Molecular Plant-Microbe Interactions® 10, nr 7 (wrzesień 1997): 803–11. http://dx.doi.org/10.1094/mpmi.1997.10.7.803.

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The location of lipopolysaccharides produced by Xanthomonas axonopodis pv. manihotis during pathogenesis on cassava (Manihot esculenta) was determined by fluorescence and electron microscopy immunolabeling with monoclonal antibodies. During the early stages of infection, pathogen lipopolysaccharides were detected on the outer surface of the bacterial envelope and in areas of the plant middle lamellae in the vicinity of the pathogen. Later in the infection process, lipopolysaccharide-specific antibodies bound to areas where the plant cell wall was heavily degraded. Lipopolysaccharides were not detected in the fibrillar matrix filling intercellular spaces of infected cassava leaves. Monoclonal antibodies specific for the exopolysaccharide xanthan side chain labeled the bacteria, the fibrillar matrix, and portions of the host cell wall. The association of Xanthomonas lipopolysaccharides with host cell walls during plant infection is consistent with a role of these bacterial extracellular polysaccharides in the infection process.

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Chapman, Matt R., i C. Cheng Kao. "EpsR Modulates Production of Extracellular Polysaccharides in the Bacterial Wilt Pathogen Ralstonia(Pseudomonas) solanacearum". Journal of Bacteriology 180, nr 1 (1.01.1998): 27–34. http://dx.doi.org/10.1128/jb.180.1.27-34.1998.

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ABSTRACT Ralstonia solanacearum is the causal agent of bacterial wilt of many agriculturally important crops. Exopolysaccharide synthesized by products of the epsI operon is the major virulence factor for R. solanacearum. Expression ofepsI has been demonstrated to be under the control of several proteins, including several two-component regulators. Overexpression of EpsR was found previously to reduce the amount of synthesis specifically from the epsI promoter. Here we present data that a single chromosomal copy of epsRactivates the epsI promoter, suggesting that EpsR is a concentration-dependent effector of epsI gene expression. Furthermore, the ability of EpsR to modulate epsIexpression is dependent on the phosphorylation state of EpsR. Gel mobility shift assays suggest that EpsR can specifically bind theepsI promoter and that this binding requires a phosphorylated form of EpsR.

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Poorni, S., i K. A. Natarajan. "Flocculation behaviour of hematite–kaolinite suspensions in presence of extracellular bacterial proteins and polysaccharides". Colloids and Surfaces B: Biointerfaces 114 (luty 2014): 186–92. http://dx.doi.org/10.1016/j.colsurfb.2013.09.049.

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Lee, I.-Chiao, Graziano Caggianiello, Iris I. van Swam, Nico Taverne, Marjolein Meijerink, Peter A. Bron, Giuseppe Spano i Michiel Kleerebezem. "Strain-Specific Features of Extracellular Polysaccharides and Their Impact on Lactobacillus plantarum-Host Interactions". Applied and Environmental Microbiology 82, nr 13 (22.04.2016): 3959–70. http://dx.doi.org/10.1128/aem.00306-16.

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ABSTRACTLactobacilli are found in diverse environments and are widely applied as probiotic, health-promoting food supplements. Polysaccharides are ubiquitously present on the cell surface of lactobacilli and are considered to contribute to the species- and strain-specific probiotic effects that are typically observed. TwoLactobacillus plantarumstrains, SF2A35B and Lp90, have an obvious ropy phenotype, implying high extracellular polysaccharide (EPS) production levels. In this work, we set out to identify the genes involved in EPS production in theseL. plantarumstrains and to demonstrate their role in EPS production by gene deletion analysis. A modelL. plantarumstrain, WCFS1, and its previously constructed derivative that produced reduced levels of EPS were included as reference strains. The constructed EPS-reduced derivatives were analyzed for the abundance and sugar compositions of their EPS, revealingcps2-like gene clusters in SF2A35B and Lp90 responsible for major EPS production. Moreover, these mutant strains were tested for phenotypic characteristics that are of relevance for their capacity to interact with the host epithelium in the intestinal tract, including bacterial surface properties as well as survival under the stress conditions encountered in the gastrointestinal tract (acid and bile stress). In addition, the Toll-like receptor 2 (TLR2) signaling and immunomodulatory capacities of the EPS-negative derivatives and their respective wild-type strains were compared, revealing strain-specific impacts of EPS on the immunomodulatory properties. Taken together, these experiments illustrate the importance of EPS inL. plantarumstrains as a strain-specific determinant in host interaction.IMPORTANCEThis study evaluates the role of extracellular polysaccharides that are produced by different strains ofLactobacillus plantarumin the determination of the cell surface properties of these bacteria and their capacity to interact with their environment, including their signaling to human host cells. The results clearly show that the consequences of removal of these polysaccharides are very strain specific, illustrating the diverse and unpredictable roles of these polysaccharides in the environmental interactions of these bacterial strains. In the context of the use of lactobacilli as health-promoting probiotic organisms, this study exemplifies the importance of strain specificity.

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Ewert, Marcela, i Jody W. Deming. "Selective retention in saline ice of extracellular polysaccharides produced by the cold-adapted marine bacteriumColwellia psychrerythraeastrain 34H". Annals of Glaciology 52, nr 57 (2011): 111–17. http://dx.doi.org/10.3189/172756411795931868.

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AbstractThe retention of salts in laboratory-grown ice was compared to the retention of extracellular polysaccharide substances (EPS) produced by the cold-adapted marine gammaproteobacterium,Colwellia psychrerythraeastrain 34H. Saline ice was formed, by means of a cold-finger apparatus, from artificial sea-water solutions containing either native dissolved EPS from strain 34H, the same EPS but heat-treated, or dissolved EPS from the uninoculated growth medium. Results indicated that only the native (unheated) EPS of strain 34H was retained preferentially in the ice. Temperature and volumetric measurements of the ice further suggested a link between the heat-labile fraction of this EPS of marine bacterial origin and potential habitat alteration. Bacterial EPS may join algal EPS in our understanding of how extracellular polymers help to establish and sustain the microbial community that inhabits sea ice.

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Ghosh, Sreejita, Dibyajit Lahiri, Moupriya Nag, Ankita Dey, Tanmay Sarkar, Sushil Kumar Pathak, Hisham Atan Edinur, Siddhartha Pati i Rina Rani Ray. "Bacterial Biopolymer: Its Role in Pathogenesis to Effective Biomaterials". Polymers 13, nr 8 (12.04.2021): 1242. http://dx.doi.org/10.3390/polym13081242.

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Bacteria are considered as the major cell factories, which can effectively convert nitrogen and carbon sources to a wide variety of extracellular and intracellular biopolymers like polyamides, polysaccharides, polyphosphates, polyesters, proteinaceous compounds, and extracellular DNA. Bacterial biopolymers find applications in pathogenicity, and their diverse materialistic and chemical properties make them suitable to be used in medicinal industries. When these biopolymer compounds are obtained from pathogenic bacteria, they serve as important virulence factors, but when they are produced by non-pathogenic bacteria, they act as food components or biomaterials. There have been interdisciplinary studies going on to focus on the molecular mechanism of synthesis of bacterial biopolymers and identification of new targets for antimicrobial drugs, utilizing synthetic biology for designing and production of innovative biomaterials. This review sheds light on the mechanism of synthesis of bacterial biopolymers and its necessary modifications to be used as cell based micro-factories for the production of tailor-made biomaterials for high-end applications and their role in pathogenesis.

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Li, Ning, Hiroyasu Satoh i Takashi Mino. "Dynamics of dewaterability and bacterial populations in activated sludge". Water Science and Technology 66, nr 8 (1.10.2012): 1634–40. http://dx.doi.org/10.2166/wst.2012.360.

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Relationships of bacterial populations and extracellular polymer substances (EPS) to dewaterability of activated sludge were studied on three laboratory-scale activated sludge reactors fed with synthetic wastewater. Dewaterability of activated sludge was evaluated by a novel method developed by the authors, in which small amount of sludge was centrifugally dewatered, and its water content was measured. Bacterial populations during the reactor operation were analyzed by the polymerase chain reaction/terminal-restriction fragment length polymorphism (PCR/T-RFLP) targeted at a partial 16S rRNA gene. Extracellular polymeric substances (EPS) were extracted using cation exchange resin (CER), and polysaccharides and total protein in EPS were determined. Some of the dominant terminal-restriction fragments (T-RFs) were observed to have significant relationships with dewaterability of sludge, and it was suggested that bacterial species corresponding to those peaks significantly affected dewaterability. On the other hand, significant relationships were not found between EPS concentration and dewaterability of sludge.

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Trček, Janja, Iztok Dogsa, Tomaž Accetto i David Stopar. "Acetan and Acetan-Like Polysaccharides: Genetics, Biosynthesis, Structure, and Viscoelasticity". Polymers 13, nr 5 (7.03.2021): 815. http://dx.doi.org/10.3390/polym13050815.

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Bacteria produce a variety of multifunctional polysaccharides, including structural, intracellular, and extracellular polysaccharides. They are attractive for the industrial sector due to their natural origin, sustainability, biodegradability, low toxicity, stability, unique viscoelastic properties, stable cost, and supply. When incorporated into different matrices, they may control emulsification, stabilization, crystallization, water release, and encapsulation. Acetan is an important extracellular water-soluble polysaccharide produced mainly by bacterial species of the genera Komagataeibacter and Acetobacter. Since its original description in Komagataeibacter xylinus, acetan-like polysaccharides have also been described in other species of acetic acid bacteria. Our knowledge on chemical composition of different acetan-like polysaccharides, their viscoelasticity, and the genetic basis for their production has expanded during the last years. Here, we review data on acetan biosynthesis, its molecular structure, genetic organization, and mechanical properties. In addition, we have performed an extended bioinformatic analysis on acetan-like polysaccharide genetic clusters in the genomes of Komagataeibacter and Acetobacter species. The analysis revealed for the first time a second acetan-like polysaccharide genetic cluster, that is widespread in both genera. All species of the Komagataeibacter possess at least one acetan genetic cluster, while it is present in only one third of the Acetobacter species surveyed.

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Pánková, I., i B. Kokošková. "Sensitivity and specificity of monoclonal antibody Mn-Cs1 for detection and determination of Clavibacter michiganensis subsp. sepedonicus, the causal agent of bacterial ring rot of potato". Plant Protection Science 38, No. 4 (6.02.2012): 117–24. http://dx.doi.org/10.17221/4866-pps.

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Monoclonal antibody Mn-Cs1 with a high level of sensitivity and specificity for detection and determination of Clavibacter michiganensis subsp. sepedonicus was prepared. Strain C. m. subsp. sepedonicus NCPPB 3467 (as whole cell antigen and extracellular polysaccharides) was used for immunisation of four mice Balb/c. After cloning and verifying, two stable hybridoma clones were gained. One monoclonal antibody, designated Mn-Cs1, was used in all tests. It reacted intensely with extracellular polysaccharides from homologous antigen (> 0.5 mg/ml), weakly with proteins from cell walls (> 200 μg/ml) and with whole homologous antigen (concentration 104–103 cfu/ml) in DAS-ELISA. Monoclonal antibody Mn-Cs1 showed a high level of specificity. It reacted neither with bacterial strains of closely related subspecies of Clavibacter michiganensis (C. m. subsp. michiganensis and C. m. subsp. insidiosus) nor with the saprophytic bacteria Pseudomonas fluorescens and Pantoea agglomerans.

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Lin, Huirong, Shuting Zhang, Song Gong, Shenghua Zhang i Xin Yu. "Characterization, Microbial Community Structure, and Pathogen Occurrence in Urban Faucet Biofilms in South China". BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/401672.

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The composition and microbial community structure of the drinking water system biofilms were investigated using microstructure analysis and 454 pyrosequencing technique in Xiamen city, southeast of China. SEM (scanning electron microscope) results showed different features of biofilm morphology in different fields of PVC pipe. Extracellular matrix material and sparse populations of bacteria (mainly rod-shaped and coccoid) were observed. CLSM (confocal laser scanning microscope) revealed different distributions of attached cells, extracellular proteins,α-polysaccharides, andβ-polysaccharides. The biofilms had complex bacterial compositions. Differences in bacteria diversity and composition from different tap materials and ages were observed. Proteobacteria was the common and predominant group in all biofilms samples. Some potential pathogens (Legionellales, Enterobacteriales, Chromatiales, and Pseudomonadales) and corrosive microorganisms were also found in the biofilms. This study provides the information of characterization and visualization of the drinking water biofilms matrix, as well as the microbial community structure and opportunistic pathogens occurrence.

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Giroldo, Danilo, Armando A. H. Vieira i Berit S. Paulsen. "Extracellular polysaccharides produced by a tropical cryptophyte as a carbon source for natural bacterial populations". European Journal of Phycology 40, nr 3 (sierpień 2005): 241–49. http://dx.doi.org/10.1080/09670260500192810.

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Amanat, Fatima, Amna Yaqoob, Asif Ali i Muhammad Sajjad. "Extracellular Production of Pectinase from Bacteria Isolated from Rotten Apples from Lahore, Pakistan". BioScientific Review 01, nr 03 (wrzesień 2019): 37–45. http://dx.doi.org/10.32350/bsr.0103.05.

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Pectins are intricate blends of polysaccharides which make up around 33% of plantcell wall. Despite of their presence in the greater part of plant body and in other sources, commercial production of pectin is extremely difficult. This is a systematic study that aimed to produce pectinase from bacterial species isolated from rotten apple samples. Zymography and enzyme assay through DNS method were performed to check the pectinolytic activity of bacteria isolated from rotten apple samples. Of all five bacterial species (Serratia marcescens, Klebseilla pneumoniea, Pseudomonas aeruginosa and Escherichia coli) maximum enzyme concentration was showed in Pseudomonas aeruginosa and it was 6.2 U/mL. The major achievement of this study was to screen out the most efficient pectinases producing isolate of Serratia marcescens from rotten apples that has never been reported to produce pectinase, previously.

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Lipa, Paulina, José-María Vinardell i Monika Janczarek. "Transcriptomic Studies Reveal that the Rhizobium leguminosarum Serine/Threonine Protein Phosphatase PssZ has a Role in the Synthesis of Cell-Surface Components, Nutrient Utilization, and Other Cellular Processes". International Journal of Molecular Sciences 20, nr 12 (14.06.2019): 2905. http://dx.doi.org/10.3390/ijms20122905.

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Rhizobium leguminosarum bv. trifolii is a soil bacterium capable of establishing symbiotic associations with clover plants (Trifolium spp.). Surface polysaccharides, transport systems, and extracellular components synthesized by this bacterium are required for both the adaptation to changing environmental conditions and successful infection of host plant roots. The pssZ gene located in the Pss-I region, which is involved in the synthesis of extracellular polysaccharide, encodes a protein belonging to the group of serine/threonine protein phosphatases. In this study, a comparative transcriptomic analysis of R. leguminosarum bv. trifolii wild-type strain Rt24.2 and its derivative Rt297 carrying a pssZ mutation was performed. RNA-Seq data identified a large number of genes differentially expressed in these two backgrounds. Transcriptome profiling of the pssZ mutant revealed a role of the PssZ protein in several cellular processes, including cell signalling, transcription regulation, synthesis of cell-surface polysaccharides and components, and bacterial metabolism. In addition, we show that inactivation of pssZ affects the rhizobial ability to grow in the presence of different sugars and at various temperatures, as well as the production of different surface polysaccharides. In conclusion, our results identified a set of genes whose expression was affected by PssZ and confirmed the important role of this protein in the rhizobial regulatory network.

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Guérin, Marie, Christine Robert-Da Silva, Cyrielle Garcia i Fabienne Remize. "Lactic Acid Bacterial Production of Exopolysaccharides from Fruit and Vegetables and Associated Benefits". Fermentation 6, nr 4 (21.11.2020): 115. http://dx.doi.org/10.3390/fermentation6040115.

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Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to their chemical composition and structure. The most prominent exopolysaccharide (EPS) producing lactic acid bacteria are Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus and Bifidobacterium sp. The EPS biosynthesis and regulation pathways are under the dependence of numerous factors as producing-species or strain, nutrient availability, and environmental conditions, resulting in varied carbohydrate compositions and beneficial properties. The interest is growing for fruits and vegetables fermented products, as new functional foods, and the present review is focused on exploring the EPS that could derive from lactic fermented fruit and vegetables. The chemical composition, biosynthetic pathways of EPS and their regulation mode is reported. The consequences of EPS on food quality, especially texture, are explored in relation to producing species. Attention is given to the scientific investigations on health benefits attributed to EPS such as prebiotic, antioxidant, anti-inflammatory and cholesterol lowering activities.

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Lebeer, Sarah, Tine L. A. Verhoeven, Grégory Francius, Geert Schoofs, Ivo Lambrichts, Yves Dufrêne, Jos Vanderleyden i Sigrid C. J. De Keersmaecker. "Identification of a Gene Cluster for the Biosynthesis of a Long, Galactose-Rich Exopolysaccharide in Lactobacillus rhamnosus GG and Functional Analysis of the Priming Glycosyltransferase". Applied and Environmental Microbiology 75, nr 11 (3.04.2009): 3554–63. http://dx.doi.org/10.1128/aem.02919-08.

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ABSTRACT Cell surface polysaccharides have an established role as virulence factors in human bacterial pathogens. Less documented are the biosynthesis and biological functions of surface polysaccharides in beneficial bacteria. We identified a gene cluster that encodes the enzymes and regulatory and transporter proteins for the different steps in the biosynthesis of extracellular polysaccharides (EPS) of the well-documented probiotic strain Lactobacillus rhamnosus GG. Subsequent mutation of the welE gene, encoding the priming glycosyltransferase within this cluster, and comparative phenotypic analyses of wild-type versus mutant strains confirmed the specific function of this gene cluster in the biosynthesis of high-molecular-weight, galactose-rich heteropolymeric EPS molecules. The phenotypic analyses included monomer composition determination, estimation of the polymer length of the isolated EPS molecules, and single-molecule force spectroscopy of the surface polysaccharides. Further characterization of the welE mutant also showed that deprivation of these long, galactose-rich EPS molecules results in an increased adherence and biofilm formation capacity of L. rhamnosus GG, possibly because of less shielding of adhesins such as fimbria-like structures.

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Sapountzis, Panagiotis, Mariya Zhukova, Lars H. Hansen, Søren J. Sørensen, Morten Schiøtt i Jacobus J. Boomsma. "Acromyrmex Leaf-Cutting Ants Have Simple Gut Microbiota with Nitrogen-Fixing Potential". Applied and Environmental Microbiology 81, nr 16 (5.06.2015): 5527–37. http://dx.doi.org/10.1128/aem.00961-15.

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ABSTRACTAnts and termites have independently evolved obligate fungus-farming mutualisms, but their gardening procedures are fundamentally different, as the termites predigest their plant substrate whereas the ants deposit it directly on the fungus garden. Fungus-growing termites retained diverse gut microbiota, but bacterial gut communities in fungus-growing leaf-cutting ants have not been investigated, so it is unknown whether and how they are specialized on an exclusively fungal diet. Here we characterized the gut bacterial community of PanamanianAcromyrmexspecies, which are dominated by only four bacterial taxa:Wolbachia,Rhizobiales, and twoEntomoplasmatalestaxa. We show that theEntomoplasmatalescan be both intracellular and extracellular across different gut tissues,Wolbachiais mainly but not exclusively intracellular, and theRhizobialesspecies is strictly extracellular and confined to the gut lumen, where it forms biofilms along the hindgut cuticle supported by an adhesive matrix of polysaccharides. Tetracycline diets eliminated theEntomoplasmatalessymbionts but hardly affectedWolbachiaand only moderately reduced theRhizobiales, suggesting that the latter are protected by the biofilm matrix. We show that theRhizobialessymbiont produces bacterial NifH proteins that have been associated with the fixation of nitrogen, suggesting that these compartmentalized hindgut symbionts alleviate nutritional constraints emanating from an exclusive fungus garden diet reared on a substrate of leaves.

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Bruckner, Christian G., Rahul Bahulikar, Monali Rahalkar, Bernhard Schink i Peter G. Kroth. "Bacteria Associated with Benthic Diatoms from Lake Constance: Phylogeny and Influences on Diatom Growth and Secretion of Extracellular Polymeric Substances". Applied and Environmental Microbiology 74, nr 24 (17.10.2008): 7740–49. http://dx.doi.org/10.1128/aem.01399-08.

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ABSTRACT The composition of diatom-associated bacterial communities was studied with 14 different unialgal xenic diatom cultures isolated from freshwater epilithic biofilms of Lake Constance, Germany. A clear dominance of Alphaproteobacteria was observed, followed by Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, and Verrucomicrobia. Pure cultures of the diatom Cymbella microcephala, which was found to be dominant in epilithic biofilms in Lake Constance, were cocultivated with six associated bacterial strains. All these bacterial strains were able to grow in C. microcephala cultures in the absence of organic cosubstrates. Diatom growth was generally enhanced in the presence of bacteria, and polysaccharide secretion was generally increased in the presence of Proteobacteria. The monomer composition of extracellular polysaccharides of C. microcephala changed in relation to the presence of different bacteria, but the dominant monomers were less affected. Our results indicate that these changes were caused by the diatom itself rather than by specific bacterial degradation. One Bacteroidetes strain strongly influenced carbohydrate secretion by the alga via extracellular soluble compounds. Biofilms were formed only in the presence of bacteria. Phylogenetic analysis and coculture studies indicate an adaptation of Proteobacteria and Bacteroidetes to the microenvironment created by the diatom biofilm.

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Lerner, Anat, Susana Castro-Sowinski, Angel Valverde, Hadas Lerner, Rachel Dror, Yaacov Okon i Saul Burdman. "The Azospirillum brasilense Sp7 noeJ and noeL genes are involved in extracellular polysaccharide biosynthesis". Microbiology 155, nr 12 (1.12.2009): 4058–68. http://dx.doi.org/10.1099/mic.0.031807-0.

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Azospirillum brasilense is a plant root-colonizing bacterium that exerts beneficial effects on the growth of many agricultural crops. Extracellular polysaccharides of the bacterium play an important role in its interactions with plant roots. The pRhico plasmid of A. brasilense Sp7, also named p90, carries several genes involved in synthesis and export of cell surface polysaccharides. We generated two Sp7 mutants impaired in two pRhico-located genes, noeJ and noeL, encoding mannose-6-phosphate isomerase and GDP-mannose 4,6-dehydratase, respectively. Our results demonstrate that in A. brasilense Sp7, noeJ and noeL are involved in lipopolysaccharide and exopolysaccharide synthesis. noeJ and noeL mutant strains were significantly altered in their outer membrane and cytoplasmic/periplasmic protein profiles relative to the wild-type strain. Moreover, both noeJ and noeL mutations significantly affected the bacterial responses to several stresses and antimicrobial compounds. Disruption of noeL, but not noeJ, affected the ability of the A. brasilense Sp7 to form biofilms. The pleiotropic alterations observed in the mutants could be due, at least partially, to their altered lipopolysaccharides and exopolysaccharides relative to the wild-type.

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Lorite, María J., Ariana Casas-Román, Lourdes Girard, Sergio Encarnación, Natalia Díaz-Garrido, Josefa Badía, Laura Baldomá, Daniel Pérez-Mendoza i Juan Sanjuán. "Impact of c-di-GMP on the Extracellular Proteome of Rhizobium etli". Biology 12, nr 1 (26.12.2022): 44. http://dx.doi.org/10.3390/biology12010044.

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Extracellular matrix components of bacterial biofilms include biopolymers such as polysaccharides, nucleic acids and proteins. Similar to polysaccharides, the secretion of adhesins and other matrix proteins can be regulated by the second messenger cyclic diguanylate (cdG). We have performed quantitative proteomics to determine the extracellular protein contents of a Rhizobium etli strain expressing high cdG intracellular levels. cdG promoted the exportation of proteins that likely participate in adhesion and biofilm formation: the rhizobial adhesion protein RapA and two previously undescribed likely adhesins, along with flagellins. Unexpectedly, cdG also promoted the selective exportation of cytoplasmic proteins. Nearly 50% of these cytoplasmic proteins have been previously described as moonlighting or candidate moonlighting proteins in other organisms, often found extracellularly. Western blot assays confirmed cdG-promoted export of two of these cytoplasmic proteins, the translation elongation factor (EF-Tu) and glyceraldehyde 3-phosphate dehydrogenase (Gap). Transmission Electron Microscopy immunolabeling located the Gap protein in the cytoplasm but was also associated with cell membranes and extracellularly, indicative of an active process of exportation that would be enhanced by cdG. We also obtained evidence that cdG increases the number of extracellular Gap proteoforms, suggesting a link between cdG, the post-translational modification and the export of cytoplasmic proteins.

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Artykuły w czasopismach na temat „Extracellular Bacterial Polysaccharides (ECP)”

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