Hossain S.M.Z.,University of Waterloo |
Hossain S.M.Z.,Jubail Industrial College JIC |
Bojko B.,University of Waterloo |
Pawliszyn J.,University of Waterloo
Analytica Chimica Acta | Year: 2013
Monitoring extracellular metabolites of bacteria is very useful for not only metabolomics research but also for assessment of the effects of various chemicals, including antimicrobial agents and drugs. Herein, we describe the automated headspace solid-phase microextraction (HS-SPME) method coupled with gas chromatography-mass spectrometry (GC-MS) for the qualitative as well as semi-quantitative determination of metabolic responses of Escherichia coli to an antimicrobial agent, cinnamaldehyde. The minimum inhibitory concentration of cinnamaldehyde was calculated to be 2gL-1. We found that cinnamaldehyde was an important factor influencing the metabolic profile and growth process. A higher number of metabolites were observed during the mid-logarithmic growth phase. The metabolite variations (types and concentrations) induced by cinnamaldehyde were dependent on both cell density and the dose of cinnamaldehyde. Simultaneously, 25 different metabolites were separated and detected (e.g., indole, alkane, alcohol, organic acids, esters, etc.) in headspace of complex biological samples due to intermittent addition of high dose of cinnamaldehyde. The study was done using an automated system, thereby minimizing manual workup and indicating the potential of the method for high-throughput analysis. These findings enhanced the understanding of the metabolic responses of E. coli to cinnamaldehyde shock effect and demonstrated the effectiveness of the SPME-GC-MS based metabolomics approach to study such a complex biological system. © 2013 Elsevier B.V.
Hussain A.,Jubail industrial college JIC |
Riyas S.,Jubail industrial college JIC
Electronic Journal of Environmental, Agricultural and Food Chemistry | Year: 2012
Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today's urban and industrial society, there is no escaping from exposure to toxic chemicals and heavy metals. Humans are more likely to be exposed to heavy metal contamination from the dust that adheres to edible plants than from bioaccumulation. This is because it is very difficult to wash off all the dust particles from the plant material before ingesting them. An atomic absorption spectroscopic method has been used for the determination of Calcium, Copper, Magnesium, Sodium and Iron in vegetables. Vegetable samples such as potato, sweet potato, carrot, green pepper, lettuce, chick peas, beans, parsley, broccoli, and radish leaves and root.