Rapid lipid profiling of bacteria by online MALDI-TOF mass spectrometry

Abstract

a b s t r a c tThe rapid identification of bacteria is of increasing interest in food, biosafety, and clinical analysis. In this paper, we report a technique for rapid lipid profiling of bacteria by online droplet-deposited MALDI mass spectrometry. In the experiment, lipids in bacterial cells (Escherichia coli, Salmonella, and Bacillus subtilis) are extracted with the mixture of chloroform/methanol via ultrasonication. The extracts are nebulized into suspended droplets and then instantly analyzed with an online droplet-deposited MALDI-TOF mass spectrometer. The lipid profiles of the three bacteria cultured in nutrient broth and LB (Lysogeny Broth) medium are obtained. The lipids phosphatidylethanolamine (PE), diglycosyl diacylglycerol (DGDG), and phosphatidylglycerol (PG) are observed in the MALDI-TOF mass spectra. The MALDI-TOF mass spectrum of each bacterial extract shows a characteristic profile. The experimental results demonstrate that the present technique is capable of conducting rapid lipid analysis and has the potential for rapid bioaerosol detection.

Classification of Bacillus and Brevibacillus species using rapid analysis of lipids by mass spectrometry

“…Lipids were extracted from Bacillus and Brevibacillus using chloroform/methanol (2:1) since this method was used previously with successful outcomes [ 10 , 12 , 44 ]. The MALDI-TOF-MS spectra of lipids extracted from all seven species— B. amyloliquefaciens B0177, B. cereus B0002, Br.…”

“…Several studies have confirmed that phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) are the most abundant phospholipids in bacteria such as Bacillus spp. [ 44 , 46 , 47 ] and Escherichia coli [ 44 ]. Bacillus has also been reported to produce other categories of lipids such as digalactosyldiacylglycerol (DGDG) [ 11 , 44 ], phosphatidylcholine (PC) [ 11 , 44 , 48 ] and fatty acids [ 49 ].…”

“…[ 44 , 46 , 47 ] and Escherichia coli [ 44 ]. Bacillus has also been reported to produce other categories of lipids such as digalactosyldiacylglycerol (DGDG) [ 11 , 44 ], phosphatidylcholine (PC) [ 11 , 44 , 48 ] and fatty acids [ 49 ]. These significant lipid features were subjected to MS/MS analysis and MS n analysis on MALDI-TOF/TOF, as well as Orbitrap MS respectively in order to obtain structural information to validate our putative assignments.…”

Advanced Mass Spectrometry

“…Effect of thermal processing [66] LC-TOF Analysis of pesticides in fruits and vegetables [67] GC-TOF Quantitative analysis of acetaldehyde in foods consumed [68] LC-TOF Screening natural antioxidants in peanut shell [69] UHPLC-TOF Hexabromocyclododecane diastereomers [70] Type Application References UHPLC-TOF 19 antibiotics in dairy products [71] MALDI-TOF Microscale strategy to detect spermine and spermidine in food [72] LC-TOF Determination of phthalates in edible salts from food markets in Korea [73] LC-QqTOF Simultaneous determination five major antioxidant compounds [74] MALDI-TOF Monitoring of she-donkey's milk contamination or adulteration [75] MALDI-TOF Quantitating curcumin in food condiments and dietary supplements and screening of acrylamide-induced ROS protein indicators [76] LC-QqTOF Quantitating curcumin in food condiments and dietary supplements and screening of acrylamide-induced ROS protein indicators [45] UHPLC-TOF Analysis of illicit dietary supplements sold in the Italian market: Identification of a sildenafil thioderivative as adulterant [46] LC-TOF Simultaneous investigation of sesquiterpenes, pyrrolizidine alkaloids, and N-oxides in butterbur (Petasites hybridus) [77] UHPLC-QqTOF Determination of 141 pesticides in tea [78] UHPLC-QqTOF Determination of tadalafil and N-desmethylsibutramine in health and dietary supplements [79] LC-QqTOF Seven fluorescent whitening agents in food contact paper package materials [80] Lipidomics GC × GC-TOF Unsaponifiable fraction of lipids belonging to various types of milk [22] UHPLC-QqTOF Rapid and highly accurate detection of steryl glycoside [81] MALDI-TOF Rapid lipid profiling of bacteria [82] MALDI-TOF Detection of glycated phospholipids in heattreated food samples [83] …”

Improvement in Staphylococcus and Bacillus strain differentiation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiling by using microwave-assisted enzymatic digestion

“…Demands for rapid and reliable identification of pathogens have brought a number of alternatives to the classical MALDI‐TOF MS protein profiling sample preparation protocols . Identification can be also accomplished by the profiling of bacterial lipids using an online droplet‐deposited MALDI‐TOF MS, as shown with Escherichia coli , Salmonella , and Bacillus subtilis . Extensive and advanced computational analysis may also contribute to improvements in the discriminatory power of the method.…”