Changes of DNA quality and meat physicochemical properties in bovine supraspinatus muscle during microwave heating

BACKGROUND

The responses of foods to microwave exposure are usually evaluated only in terms of physicochemical properties, thus undervaluing the importance of DNA in an authentication process by methods based on polymerase chain reaction (PCR). In this study, the time effect of microwave heating on some meat physicochemical properties and DNA quality has been investigated.

RESULTS

Cooking loss, instrumental colour, pH and other physicochemical parameters varied significantly during microwave cooking, reaching the lowest/highest values after 2.5 min of cooking. The exposure of meat to microwaves was found to affect characteristically the quality of extracted DNA (i.e. yield, purity and degradation). PCR products of both mitochondrial and nuclear regions were successfully observed in all samples. However, the band for large fragments became progressively fainter as treatment time increased.

CONCLUSIONS

Microwave heating caused physicochemical changes in bovine supraspinatus muscle and influenced characteristically the yield and integrity of the extracted DNA, indicating that an accurate DNA quantification and a rational choice of the genes (i.e. mtDNA versus nDNA, fragment size, etc.) to be amplified are fundamental in an authentication process by PCR-based methods.

[Influence of N-acylethanolamines on embryonic cell culture survival under the effect of irradiation]

The effects of the N-stearoylethanolamine (NSE), N-oleoylethanolamine (OEA) and N-acylethanolamine (NAE) mixture on the cell survival, apoptosis and activity of mitochondrial succinate dehydrogenase (SDG) and glycerophosphate dehydrogenase (GFDG) in embryonic cell culture under normal conditions and irradiation were compared in the work. It was shown, that all investigated NAE were able to modulate the proliferative activity of intact cells as well as irradiation-exposed cells in concentration-depended manner. The most pronounced effect was observed under the NAE mixture action. It was established, that NAE prevented the damage effects of the irradiation and diminished the activation of apoptotic cell death. It was found that NSE and OEA decreased the activity of the SDG (42.3 and 44.14%, accordingly) and the GFDG activity (14.67 and 17.33%, accordingly) in embryonic cell culture, while addition of the NAE mixture decreased SDG activity by 20%, at the same time GFDG activity increased by 20%. Our findings suggested that antiproliferative effects of NAE depended on their influence on mitochondrial functioning.

[Ultrastructure of skeletal muscle tissue of microwave damaged chick embryos]

The effect of ultrahigh-frequency energy of electromagnetic field of low intensity on certain morphometric indices of intracellular organoids and on cellular ultrastructure were studied in the developing skeletal muscular tissue of chick embryos. In the skeletal muscles of irradiated embryos a limited cellular destruction, structural disorders in myonic organoids were revealed. Reactive-recovery processes manifested themselves in hyperplasy and hypertrophy of organoids, in activation of protein synthesis, in increasing amount of myosatellites. At early stages after irradiation peripheral mitochondria are subjected to greater changes. After hatching, central mitochondria in myons suffer more. Quantitative changes in myonic organoids and degree of their destruction seem to depend on.a peculiar differentiation of the muscular tissue, blood supply and innervation of the muscle as an organ.

Argon laser microirradiation of mitochondria in rat myocardial cells in tissue culture. VII. fibrillation in ventricle and auricle cells

Rat myocardial cells in vitro were irradiated in individual mitochondria with an argon ion laser microbeam. The contractile respone termed fibrillation in single and multicellular groups of both ventricle and auricle cells were compared. Specific correlations were made between fibrillation duration, the number of cells in the group, and the number of times the cells had fibrillated. Correlations were also made for the number of laser shots needed to induce fibrillation and the number of cells in the group. Another set of correlations were made between the pre-irradiation beat frequency and the beat frequency following recovery. Several differences and similarities of the above parameters were detected between auricle and ventricle cells. A comparison of the morphology and ultrastructure of auricle and ventricle cells also revealed significant differences.