Tag Archives: hypothermia

Differential impact of the temperature stress and soil drought on lipoxygenase activity in winter rye plants

L. M. Babenko, K. O. Romanenko*, I. V. Kosakivska

M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: katerynaromanenko4@gmail.com

Received: 5 July 2021; Accepted: 12 November 2021

Lipoxygenase cascade is a source of physiologically active compounds, the presence of which is considered not only as a sign of damage but also as a trigger of adaptive responses to stress. The aim of the study was to determine the effects of short-term (2 h) heat (40°C) and cold (4°C) temperature stress and moderate soil drought on lipoxygenase (LOX) activity in 14-day-old winter rye (Secale cereale L. ‘Boguslavka’) plants. The shoots were found to have both membrane-bound 9-LOX1 and 9-LOX2 and soluble 13-LOX activity, the roots – membrane-bound 9-LOX activity. After heat stress, the activity of 9-LOX1 and 9-LOX2 in the shoots increased by 3 and 2 times, respectively, the activity of 9-LOX in the roots – by 2 times, and 13-LOX activity in the shoots decreased by 1.5 times. After the cold stress, the activity of 9-LOX1 and 9-LOX2 in the shoots raised by almost 1.5 times, the activity of 9-LOX in the roots – by 1.2 times. Moderate soil drought caused enhancement in the activity of both membrane-bound isoforms of 9-LOX in the shoots by 1.5–2 times and in the roots – by 3 times. The established fluctuations indicate that molecular forms of LOX with different localization are differentially involved in the winter rye response to temperature stress and moderate soil drought.

Fatty acids composition of inner mitochondrial membrane of rat cardiomyocytes and hepatocytes during hypoxia-hypercapnia

S. V. Khyzhnyak, S. V. Midyk, S. V. Sysoliatin, V. М. Voitsitsky

National University of Life and Environmental Sciences of Ukraine, Kyiv;
е-mail: khs2014@ukr.net

We studied the influence of hypoxic-hypercapnic environment under the effect of hypothermia (artificial hibernation) on fatty acids spectrum of inner mitochondrial membrane (IMM) lipids of rat cardiomyocytes and hepatocytes. Specific for cellular organelles redistribution of IMM fatty acids was determined. It led to the reduction of total amount of saturated fatty acids (SFAs) and increase of unsaturated fatty acids (UFAs) in cardiomyocytes and to the increase of SFAs and decrease of UFAs in hepatocytes. The decrease in the content of oleic acid and increased content of arachidonic and docosahexaenoic acids in IMM were shown. This may be due to their role in the regulatory systems during hibernation, as well as following exit therefrom. It is assumed that artificial hibernation state is characterized by the stress reaction leading to optimal readjustment of fatty acids composition of membrane lipids, which supports functional activity of mitochondria in hepatocytes and cardiomyocytes.

Oxygen binding by marine fish blood under hypothermic experimental conditions

A. A. Soldatov1, I. A. Parfyonova2

1Institute of Biology of Southern Seas, National Academy of Science of Ukraine, Sevastopol;
e-mail: alekssoldatov@yandex.ru;
2Sevastopol National Technical University, Ukraine

Influence of temperature in the range of 1-15 °С on oxygen binding properties of blood of thermophilic – golden mullet (Liza aurata), anchovy (Engraulis encrasicolus), and cold-tolerant – sardelle (Clupeonella cultriventris) fishes has been investigated under experimental conditions. Heat dependence of oxygenation reaction in thermophilic fish blood at temperature below 10 °C considerably increases, which is evidenced by high ΔH values. That is accompanied by a substantial increase of blood oxygen affinity and complicates blood deoxygenation at the tissue level. This reac­tion is apparently determined by the change of hemoglobin interaction with intraerythrocyte medium. The concentration of NTP in erythrocytes increases, that partially compensates negative changes of blood oxygen affinity (parameter P50 is raised) under long-term maintenance of fishes at 5 °С. However this reaction is not observed at low temperatures (1-2 °C).