A new book on Bacterial Polysaccharides has been published by Caister Academic Press. The book covers current research and biotechnological applications. Taking an interdisciplinary view the authors examine bacterial polysaccharides from molecular biology, genome-, transcriptome- and proteome-wide perspectives, and include ecological aspects and systems biology approaches.

Bacterial Polysaccharides: Current Innovations and Future Trends
Publisher: Caister Academic Press
Editor: Matthias Ullrich
Publication date: June 2009 (available now)
ISBN: 978-1-904455-45-5

Topics include:
* The Polysaccharide Peptidoglycan and How it is Influenced by (Antibiotic) Stress
* Genetics and Regulation of Bacterial Lipopolysaccharide Synthesis
* Mycobacterial Cell Wall Arabinogalactang
* Genetics and Regulation of Bacterial Polysaccharide Expression in Human Pathogenic Bacteria
* Therapies Directed at Pseudomonas aeruginosa Polysaccharides
* Immune Responses to Microbial Polysaccharides
* Polysaccharides of Gram-negative Periodontopathic Bacteria
* Bacterial Polysaccharides in Dental Plaque
* Composition and Functional Role of Polysaccharides in Biofilm Infections
* Poly-N-acetyl-glucosamine as a Mediator of Bacterial Biofilm Formation
* Surface Polysaccharides as Fitness factors of Rhizospheric Nitrogen-fixing Bacteria
* Levansucrase and Levan Formation in Pseudomonas syringae and Related Organisms
* Structure, Biosynthesis, and Regulation of Capsular Exopolysaccharide of Erwinia
* Osmoregulated Periplasmic Glucans (OPGs), Alginate, and Biofilm Formation in Pseudomonas syringae
* Ecology of Exopolysaccharide Formation by Lactic Acid Bacteria
* Biosynthesis and Chemical Composition of Exopolysaccharides Produced by Lactic Acid Bacteria
* Commercial Exploitation of Homo-exopolysaccharides in Non-dairy Food Systems
* Exploitation of Exopolysaccharides from Lactic Acid Bacteria
* Synthesis of Bacterial Polysaccharides as a Limiting Factor for Biofuel Production

Bacterial Polysaccharides: Current Innovations and Future Trends

CURRENT BOOKS OF INTEREST
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Lab-on-a-Chip Technology: Biomolecular Separation and Analysis
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Labels: bacterial polysaccharides, biopolymers, polysaccharides

The peptidoglycan or murein sacculus is the stress-bearing structure of bacterial cells. It consists of glycan strands cross-linked by peptide bridges. Even though studies on murein have a very long tradition, it is not known how the glycan strands are actually arranged.

The chemical fine structure and the muropeptide composition of different Gram-negative and Gram-positive bacteria have been investigated in detail. Escherichia coli and Staphylococcus aureus are generally considered representatives for both Gram forms. During cell growth the stress-bearing structure has to be elongated and/or divided by the insertion of new and elimination of old material without losing its strength. Therefore multienzyme complexes containing both murein synthases and murein hydrolases have been postulated.

Peptidoglycan biosynthesis is the target for many antibiotics such as β-lactams, D-cycloserine and glycopeptide-antibiotics such as vancomycin. Bacteria have developed a number of different strategies for coping with antibiotic and osmotic stress.

from Ute Bertsche in Bacterial Polysaccharides: Current Innovations and Future Trends

Further reading:

1. Bacterial Polysaccharides
2. Microbial Production of Biopolymers and Polymer Precursors
3. Microbiology Books

Labels: antibiotic resistance, biopolymers, peptidoglycan, polysaccharides

The genus Xanthomonas consists of 20 plant-associated species, many of which cause important diseases of crops and ornamental plants. Individual species comprise multiple pathovars, characterized by distinctive host specificity or mode of infection. Genomics is at the center of a revolution in Xanthomonas biology. Complete genome sequences are available for nine Xanthomonas strains, representing three species and five pathovars, including vascular and non-vascular pathogens of the important models for plant biology, Arabidopsis thaliana and rice. With the diversity of complete and pending Xanthomonas genome sequences, the genus has become a superb model for understanding functional, regulatory, epidemiological, and evolutionary aspects of host- and tissue-specific plant pathogenesis.
Further reading: Damien F. Meyer and Adam J. Bogdanove Chapter 7 in Plant Pathogenic Bacteria

Furthermore, Xanthomonas strains produce the acidic exopolysaccharide xanthan gum. Because of its physical properties, xanthan gum is widely used as a viscosifer, thickener, emulsifier or stabilizer in both food and non-food industries.
Further reading: Anke Becker and Frank-Jörg Vorhölter Chapter 1 in Microbial Production of Biopolymers and Polymer Precursors

Labels: bacteriology, bacterium, biopolymers, biotechnology, xanthan, xanthomonas

Many bacteria possess the genes needed to produce cellulose. However, Gluconacetobacter xylinus (formerly Acetobacter xylinum) is used for studies of the biochemistry and genetics of cellulose biosynthesis. Structurally cellulose is a simple polysaccharide, in that it consists only of one type of sugar (glucose), and the units are linearly arranged and linked together by β-1,4 linkages only. The mechanism of biosynthesis is however rather complex, partly because in native celluloses the chains are organized as highly ordered water-insoluble fibers. Currently the key genes involved in cellulose biosynthesis and regulation are known in a number of bacteria, but many details of the biochemistry of its biosynthesis are still not clear. A survey of genome sequence databases clearly indicates that a very large number of bacteria have the genes needed to produce cellulose, and this has also been experimentally confirmed for a smaller number of organisms. The biological functions of bacterial celluloses vary among species, and range from a role as a floating device to involvement in plant root adhesion and biofilm formation.
Valla et al from Chapter 3 in Microbial Production of Biopolymers and Polymer Precursors

Further reading: Microbial Production of Biopolymers and Polymer Precursors

Labels: bacterium, biopolymers, biotechnology, cellulose

from Anke Becker and Frank-Jörg Vorhölter in Microbial Production of Biopolymers

Plant-pathogenic bacteria of the genus Xanthomonas are able to produce the acidic exopolysaccharide xanthan gum. Because of its physical properties, it is widely used as a viscosifer, thickener, emulsifier or stabilizer in both food and non-food industries. Xanthan consists of pentasaccharide repeat units composed of D-glucosyl, D-mannosyl, and D-glucuronyl acid residues in a molar ratio of 2:2:1 and variable proportions of O-acetyl and pyruvyl residues. The xanthan polymer has a branched structure with a cellulose-like backbone. Synthesis originates from glucose as substrate for synthesis of the sugar nucleotides precursors UDP-glucose, UDP-glucuronate, and GDP-mannose that are required for building the pentasaccharide repeat unit. This links the synthesis of xanthan to the central carbohydrate metabolism. The repeat units are built up at undecaprenylphosphate lipid carriers that are anchored in the cytoplasmic membrane. Specific glycosyltransferases sequentially transfer the sugar moieties of the nucleotide sugar xanthan precursors to the lipid carriers. Acetyl and pyruvyl residues are added as non-carbohydrate decorations. Mature repeat units are polymerized and exported in a way resembling the Wzy-dependent polysaccharide synthesis mechanism of Enterobacteriaceae. Products of the gum gene cluster drive synthesis, polymerization, and export of the repeat unit.

Further reading:
1. Microbial Production of Biopolymers
2. Plant Pathogenic Bacteria

Labels: bacterium, biopolymers, biotechnology, genetic engineering, xanthan, xanthomonas

A huge variety of biopolymers, such as polysaccharides, polyesters, and polyamides, are naturally produced by microorganisms. These range from viscous solutions to plastics and their physical properties are dependent on the composition and molecular weight of the polymer. The genetic manipulation of microorganisms opens up an enormous potential for the biotechnological production of biopolymers with tailored properties suitable for high-value medical application such as tissue engineering and drug delivery.

Microorganisms naturally produce a wide variety of carbohydrate molecules, yet large-scale manufacturing requires production levels much higher than the natural capacities of these organisms. Metabolic engineering efforts generate microbial strains capable of meeting the industrial demand for high synthesis levels. As both oligosaccharide and polysaccharide synthesis are carbon and energy-intensive processes, improved production of these products require similar metabolic engineering strategies. Metabolically engineered strains have successfully produced many carbohydrate products and many unexplored strategies made available from recent progress in systems biology can be used to engineer better microbial catalysts.

Further reading: Microbial Production of Biopolymers and Polymer Precursors

Labels: biopolymers, biotechnology, genetic engineering