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Peptydoglikan : budowa, rola biologiczna oraz synteza

Samaszko-Fiertek J., Dmochowska B., Madaj J.

Wiadomości Chemiczne

2015

[Z] 69, 7-8

513--540

The most important component of bacterial cell walls especially Gram-positive bacteria is peptidoglycan, called also murein, PGN. The first time this synonym was used in 1964 by Weidel and Pelzer [1]. Peptidoglycan is present in the outer layer of the cytoplasmic membrane and its structure. The structure of peptidoglycan depends on the bacteria strain. It is estimated that in Gram-negative bacteria, it occupies only about 10–20% of the total area of the cell wall, when in Gram-positive bacteria it is 50 and up to 90% of all space. Problems with isolation with high purity of biological material shows the need for developing techniques for chemical synthesis of peptidoglycan fragments and their analogs. In past few years there has been a growing interest within the synthesis of compounds glycoprotein (glycopeptides, peptidoglycan, etc.). As a basis for the construction of cell walls of many bacteria. Despite intensive research and gain significant knowledge of the physical and biological, chemical synthesis or biosynthesis (Fig. 5 and 6) of peptidoglycan, not so far failed to unambiguously determine its three-dimensional structure. The works of Kelman and Rogers [15] and Dimitriev [20] nearer picture of its structure. However, the time to develop in vivo visualization of cell structure it will be difficult to identify correctly peptidoglycan three-dimensional structure. Due to the important biological roles of murein, many research centers have taken to attempt their chemical synthesis. For biological research began to use chemically synthesized peptidoglycan fragments which guaranteed both uniform and a certain structure. An important roles in the development of methods of chemical synthesis of peptidoglycan had H. Chowdhury work, Fig. 8 [35], Hesek, Fig. 9 and 10 [36, 37], Dziarskiego [38] and Boneca [39] and Inamury [34, 40].

Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska . Część I. Kwas muraminowy jako biomarker ścian komórkowych bakterii

Mielniczuk Z., Bal K.

Wiadomości Chemiczne

2012

[Z] 66, 5-6

445-460

Microorganisms synthesize several monomeric chemical structures that are not found elsewhere in nature, e.g. muramic acid (an amino sugar) and D-amino acids (D-alanine and D-glutamic acid) are ubiquitous in bacterial peptidoglycan (PG). Specific sugars (e.g. heptoses) and 3-hydroxylated fatty acids are found in the endotoxin (lipopolysaccharide, LPS) of gram-negative bacteria [42]. The best way to protect against environmental contamination is microbial control. Methods in current use for monitoring of microorganisms mainly include culturing and direct microscopy. However, several factors including samples collection, growth conditions, incubation temperature and interaction between different organisms all affect culturing results. Additionally, culturing based methods can detect only viable organisms and they are also time consuming, sometimes taking days or weeks. However, since both living and dead microorganisms express irritating and toxic structures, they should all be taken into consideration [17]. Muramic acid (MuAc), an amino sugar, has been suggested for use as a chemical marker in gas chromatography-mass spectrometry (GC-MS) determination of bacterial peptidoglycan in both clinical and environmental samples. Several derivatives of MuAc have been applied, including the alditol acetate [1, 2], aldononitrile [3], trifluoroacetyl [4] and trimethylsilyl [5], and methyl ester O-methyl acetate [6] derivatives. Both the alditol acetate and TMS derivatives have proven suitable for the use with GC-ion-trap tandem MS [7]. The aim of our proposition is a trial of application of gas chromatography-mass spectrometry (GC-MS) method as an alternative or complement to culturing, microscopy and other assays for detection, characterization and monitoring of microbial contamination of environment (e.g. water, air, air-conditioning systems), contamination of biochemical and food production chain processes, packaging for foodstuffs etc. by direct analysis of bacterial muramic acid as a biochemical marker. A method is described for the quantitation of muramic acid, a marker of bacterial peptidoglycan as trimethylsilyl (TMS ) derivatives using GC/MS method. The described methods are fast and simple, and can be applied for monitoring of microbial contamination directly, without prior culturing, in complex environmental samples. This method can also be applied for testing processes of cleaning and disinfection on packaging materials or on both packaging materials/foodstuffs in order to decrease their microbial load and thus to ensure better shelf-life.