Bruno Cinel

Abrogation of ionizing radiation-induced G2 checkpoint and inhibition of nuclear export by Cryptocarya pyrones.

G2 checkpoint inhibitors can force cells arrested in G2 phase by DNA damage to enter mitosis. In this manner, several G2 checkpoint inhibitors can enhance killing of cancer cells by ionizing radiation and DNA-damaging chemotherapeutic agents, particularly in cells lacking p53 function. All G2 checkpoint inhibitors identified to date target protein phosphorylation by inhibiting checkpoint kinases or phosphatases. Using a phenotypic cell-based assay for G2 checkpoint inhibitors, we have screened a large collection of plant extracts and identified Z-Cryptofolione and Cryptomoscatone D2 as highly efficacious inhibitors of the G2 checkpoint. These compounds and related pyrones also inhibit nuclear export. Leptomycin B, a potent inhibitor of Crm1-mediated nuclear export, is also a very potent G2 checkpoint inhibitor. These compounds possess a reactive Michael acceptor site and do not appear promising as a radiosensitizing agents because they are toxic to unirradiated cells at checkpoint inhibitory concentrations. Nevertheless, the results show that inhibition of nuclear export is an alternative to checkpoint kinase inhibition for abrogating the G2 checkpoint and they should stimulate the search for less toxic nuclear export inhibitors.

Rapid Determination of Total Conjugated Linoleic Acid Content in Select Canadian Cheeses by 1H NMR Spectroscopy

The application of (1)H nuclear magnetic resonance (NMR) spectroscopy to the measurement of conjugated linoleic acid (CLA) content in the lipid fraction of dairy products is both a novel and inviting alternative to traditional methods such as gas chromatography (GC), which can require time-consuming sample derivatization. In this work, a newly developed, rapid, and reliable lipid extraction protocol was combined with simple, nondestructive (1)H NMR spectroscopic analysis to measure the total CLA content in CLA standards and in various Canadian cheeses from conventional, organic, and grass-fed dairy sources. The total CLA concentrations (mg/g cheese) obtained using these new extraction and analysis methods were consistent with amounts found using the modified Folch extraction and GC analysis (correlation coefficient of 0.948). Results showed that cheeses from exclusively grass-fed dairy cows were significantly higher in total CLA content than either conventional or organic cheese.

Separation of dietary omega‐3 and omega‐6 fatty acids in food by capillary electrophoresis

A lower dietary omega-6/omega-3 (n-6/n-3) fatty acid ratio (<4) has been shown to be beneficial in preventing a number of chronic illnesses. Interest exists in developing more rapid and sensitive analytical methods for profiling fatty acid levels in foods. An aqueous CE method was developed for the simultaneous determination of 15 n-3 and n-6 relevant fatty acids. The effect of pH and concentration of buffer, type and concentration of organic modifier, and additive on the separation was investigated in order to determine the best conditions for the analysis. Baseline separations of the 15 fatty acids were achieved using 40 mM borate buffer at pH 9.50 containing 50 mM SDS, 10 mM β-cyclodextrin, and 10% acetonitrile. The developed CE method has LODs of <5 mg/L and good linearity (R(2) > 0.980) for all fatty acids studied. The proposed method was successfully applied to the determination of n-3 and n-6 fatty acids in flax seed, Udo® oils and a selection of grass-fed and grain-fed beef muscle samples.

Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada

Turner, T. D., Jensen, J., Pilfold, J. L., Prema, D., Donkor, K. K., Cinel, B., Thompson, D. J., Dugan, M. E. R. and Church, J. S. 2015. Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada. Can. J. Anim. Sci. 95: 49-58. The effect of production system on intramuscular and associated trim fatty acid (FA) profiles of retail ribeye steaks from conventional and niche market organic and natural (grain- or grass-fed) beef were compared. Meat from organic grain- and grass-fed systems was leaner, containing greater proportions of polyunsaturated FA, i.e., 18:3n-3, 20:5n-3, 22:5n-3, 22:6n-3. Correspondingly, the n-6/n-3 ratios of organic grain- and grass-fed systems were 3:1, while conventional and natural grain systems had ratios of 8:1. High forage-to-grain ratio production systems increased proportions of desirable biohydrogenation intermediates (BI), including t11-18:1 and c9,t11-18:2, whereas conventional and natural grain systems elevated t10-18:1. Trim fat was similarly affected by production system, and was a relatively richer source of BI. Overall, proportions of desirable FAs, including n-3 and BI, were greater for organic grain- and grass-fed systems, emphasizing the importance of a high forage-to-grain ratio to enhance the healthfulness of beef, whereas conventional and natural grain-fed systems were largely equivalent.

Rapid determination of n-6 and n-3 fatty acid ratios in cereal grains and forages by 1H NMR spectroscopy

Abstract: Herein we describe a new method to rapidly determine the n-6/n-3 fatty acid ratios in cereal grains and forages (hydroponically-grown cereal sprouts and haylage) using 1H nuclear magnetic resonance (NMR) spectroscopy. This NMR method was found to be consistent with more established but time-consuming gas chromatographic methods (R = 0.994).

Assessing the engagement, learning, and overall experience of students operating an atomic absorption spectrophotometer with remote access technology

The use of internet‐based technologies in the teaching of laboratories has emerged as a promising education tool. This study evaluated the effectiveness of using remote access technology to operate an atomic absorption spectrophotometer in analyzing the iron content in a crude myoglobin extract. Sixty‐two students were surveyed on their level of engagement, learning, and overall experience. Feedback from students suggests that the use of remote access technology is effective in teaching students the principles of chemical analysis by atomic absorption spectroscopy.

Fatty acid profile of British Columbia suckler beef

Abstract: In this study, the influence of feeding system on the fatty acid (FA) profile of suckler beef (SB), moderate grain-fed (MG), and grass-fed (GF) beef was compared. It was found that total saturated FA content was not affected; however, greater 14:0, total polyunsaturated FA content, and lower n-6/n-3 ratio suggest some transmittance of milk FA in SB calves (P < 0.001).

Integrating Bio-Inorganic and Analytical Chemistry into an Undergraduate Biochemistry Laboratory.

Undergraduate laboratories expose students to a wide variety of topics and techniques in a limited amount of time. This can be a challenge and lead to less exposure to concepts and activities in bio‐inorganic chemistry and analytical chemistry that are closely‐related to biochemistry. To address this, we incorporated a new iron determination by atomic absorption spectroscopy exercise as part of a five‐week long laboratory‐based project on the purification of myoglobin from beef. Students were required to prepare samples for chemical analysis, operate an atomic absorption spectrophotometer, critically evaluate their iron data, and integrate these data into a study of myoglobin.