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Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska. Część 2, Kwasy 3-hydroksytłuszczowe jako biomarkery lipopolisacharydów (endotoksyn) ścian komórkowych bakterii gramujemnych

Bal K., Mielniczuk Z.

Wiadomości Chemiczne

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2016

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[Z] 70, 1-2

95--117

EN

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). Characteristic sugars (e.g. heptoses) and 3-hydroxylated fatty acids are found in the endotoxin (lipopolysaccharide, LPS) of gram-negative bacteria [1]. The best way to protect against environment contamination is microbial control. Methods in current use for monitoring microorganisms mainly include culture and direct microscopy. However, several factors, including samples collection, growth conditions, incubation temperature and interaction between different organisms all affected the culture results. Additionally, culture 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. Muramic acid has been suggested for use as a chemical marker in gas chromatography-mass spectrometry (GC-MS) determination of bacterial peptidoglycan [2]. While 3-hydroxylated fatty acids are the best proposition for use as a chemical markers in gas chromatography-mass spectrometry determination of bacterial lipopolysaccharide (endotoxin) of gram-negative bacteria in both clinical and environmental samples [38]. Two derivatives have been applied, including the trimethylsilyl (TMS) and pentafluorobenzoyl (PFBO) derivatives [80]. Both derivatives (TMS and PFBO) have been proven suitable for use with GC-ion-trap tandem MS [3]. The aim of our proposition is 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 analysis of bacterial 3-hydroxylated fatty acids as a biochemical markers. A method is described for the quantitation of methyl esters of 3-hydroxyacids, markers of bacterial lipopolysaccharide (endotoxin), as trimethylsilyl or pentafluorobenzoyl derivatives using GC/MS method. The described methods are quick and simple, can be applied for monitoring microbial contamination directly, without prior culturing, in complex environmental samples. This method can be also applied for testing processes of cleaning and disinfections on packaging materials or on both packaging materials/foodstuffs in order to decrease their microbial load and thus to ensure better shelf-life. [1] Z. Mielniczuk, K. Bal, Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska. Część I. Kwas muraminowy jako biomarker ścian komórkowych bakterii, Wiad. Chem., 2012, 66, 445. [2] K. Bal, L. Larsson, E. Mielniczuk, Z. Mielniczuk, Structure of muramic acid TMS derivative mass spectrum’s base ion (m/z=185) used for quantification of bacterial peptidoglycan, J. Microbiol. Meth., 2002, 48, 267. [3] A. Saraf, L. Larsson, Identification of microorganisms by mass spectrometry, Advances in Mass Spectrometry, 1998, 14, 449. [38] Z. Mielniczuk, E. Mielniczuk, L. Larsson, Gas chromatography-mass spectrometry methods for analysis of 2- and 3-hydroxylated fatty acids: Application for endotoxin measurement, J. Microbiol. Meth., 1993, 17, 91. [80] Z. Mielniczuk, S. Alugupalli, E. Mielniczuk, L. Larsson, Gas chromatography-mass spectrometry of lipopolysaccharide 3-hydroxy fatty acids: comparison of pentafluorobenzoyl and trimethylsilyl methyl ester derivatives, J. Chromatogr., 1992, 623, 115.

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

Mielniczuk Z., Bal K.

Wiadomości Chemiczne

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2012

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[Z] 66, 5-6

445-460

EN

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.

3

Metody badania migracji szkodliwych substancji z opakowań do żywności

Bal K., Mielniczuk Z.

Przegląd Papierniczy

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2010

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R. 66, nr 8

459-462

PL

Opakowania wykonane z tworzyw sztucznych oraz papieru i tektury, przeznaczone do kontaktu z żywnością, muszą spełniać ściśle określone wymagania sanitarno-higieniczne. Bardzo ważnym kryterium dopuszczającym do ich zastosowania stanowi oznaczanie migracji globalnej i specyficznej. Zarówno monomery jak i pomocnicze środki modyfikujące oraz składniki farb drukarskich mogą migrować z materiału opakowaniowego do żywności. Ze względu na to, że nie jest możliwe badanie migracji do wszystkich rodzajów żywności, zostały wybrane odpowiednie płyny modelowe, które są stosowane do tych badań i których zastosowanie jest regulowane odpowiednimi dyrektywami UE. Ponieważ kontrola surowców i wyrobów, które mają być zastosowane do pakowania żywności, jest konieczna dla dostosowania się do wymagań dokumentów Unii Europejskiej, niezbędne jest dysponowanie odpowiednio czułymi, selektywnymi, szybkimi i ekonomicznymi metodami badania migracji. Takimi metodami mogą być: chromatografia gazowa (GC), chromatografia gazowa sprzężona ze spektrometrią mas (GC/MS) oraz wysokosprawna chromatografia cieczowa (HPLC).

EN

Packaging made from plastics, paper and board intended to food contact must meet definite sanitary and hygienic requirements. Measurement of specific and global migration is a very important criterion of their use for this purpose. Monomers as well as modifying aids and components of printing inks can migrate from packaging material to food. Since it is not possible to test migration to all kinds of food, the model liquids complying with EU regulations were selected for the tests. As the inspection of raw materials and products used for food packaging is indispensable, the suitably sensitive, selective, fast and economical test methods are essential in fulfilling the requirements of EU legal regulations. Such methods can be: gas chromatography (GC), gas chromatography- mass spectrometry (GC/MS) and high performance liquid chromatography (HPLC).