Theoretical and Applied Veterinary Medicine (Mar 2020)
The protein ratio at different poles of the enterocytes’ cell membrane of the jejunum during the fetal stage in cattle
Abstract
Polarity plays a decisive role in ensuring the functional properties of intestinal enterocytes, the apical membrane is responsible for the hydrolysis and transport of substances, while basolateral membrane is responsible for the entry of substances into the bloodstream. For the research were used 80 two to nine months old cattle fetuses. To obtain apical and basolateral membranes from a suspension of isolated enterocytes from the cattle’s jejunum, the basic method of differential centrifugation in the author’s modification was used. New data on the concentration dynamics of individual protein fractions on the enterocytes apical and basolateral membranes from the jejunum of cattle fetuses are presented. It is established that during the late fetal stage there are dynamic changes in the polypeptide composition of the apical and basolateral membranes of enterocytes, which are characterized not only by changes in their ratio but also by redistribution between the poles of these cells. In the apical and basolateral membranes, respectively, 31 and 27 protein fractions were detected with molecular weights from 9.6 kDa to 300 kDa. At this moment, there is a decrease in the content of low molecular weight protein fractions and an increase in the proportion of high molecular weight ones. The expression and content of different polypeptide fractions on the polar domains of the jejunal enterocytes of 9-month-old cattle fetuses are characterized by a predominance of low molecular weight proteins (from 21 kDa to 33 kDa) in the apical membrane, while in the basolateral – proteins of higher molecular weight are dominant (from 35 kDa to 300 kDa). Thus, the apical membrane has a higher content of proteins with a molecular weight of 17 kDa – 8.48 times more than in basolateral (P ≤ 0.001), 21 kDa – 1.23 times more (P ≤ 0.001), 22.5 kDa – 6.39 times (P ≤ 0.001), 24 kDa – 1.29 times (P ≤ 0.001), 26 kDa – 1.56 times (P ≤ 0.001), 29 kDa – 1.27 times (P ≤ 0.01), 31 kDa – 1.54 times (P ≤ 0.001), 33 kDa – 1.61 times (P ≤ 0.001) and 46 kDa – 1.56 times (P ≤ 0.01). In contrast, in the enterocytes basolateral membrane there is a higher content of polypeptide fractions compared to that in the apical membrane, with a molecular weight of 15.5 kDa – 3.64 times more (P ≤ 0.001), 35 kDa – 1.63 times (P ≤ 0.01), 39 kDa – 1.88 times (P ≤ 0.001), 43 kDa – 1.87 times (P ≤ 0.001), 52 kDa – 1.26 times (P ≤ 0.001), 63 kDa – 1.11 times (P ≤ 0.05), 66 kDa – 1.29 times (P ≤ 0.001), 87 kDa – 3.16 times (P ≤ 0.001), 100 kDa – 3.03 times (P ≤ 0.001), 155 kDa – 1.15 times (P ≤ 0.05), 170–185 kDa – 1.50 times (P ≤ 0.001) and 300 kDa – 1.59 times (P ≤0.001).
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