Phosphoethanolamine in brain of the euritherm lake fish Perccottus glehni (Eleotridae, Perciformes, Dyb. 1877) as a phenomenon depending on temperature factor

Abstract

The present work studied effect of a seasonal decrease of environmental temperature and cold shock on pools of free amino acids (FA) in brain of the euritherm lake fish P. glehni. For the first time, non-protein amino acid, phosphoethanolamine (PEA), revealed in the great amounts under conditions of near-zero temperatures was found in brain of ectothermic animals. An intensive rise of the PEA pool from 0.3% during the summer period to 33.6% at winter was shown to occur in the brain of P. glehni as a result of a seasonal temperature decrease. In contrast, the level of taurine showing the greatest pool in comparison with other FA (29.0% of the total pool) in summer decreases to 8.9% in the beginning of winter period. Similar negative correlation between the taurine and PEA content was found under effect of acute cold shock (1°C): the taurine level decreased for 4 days from 32.2 to 14.5% of the total pool, whereas the PEA level sharply increased (from 2.1 to 15.3%). Both types of the low-temperature actions have revealed, besides PEA, an intensive rise in the pool of serine and accumulation of phosphoserine. The role of PEA in biochemical evolution and adaptation of the brain to low temperatures is discussed. It is supposed that accumulation of PEA, phosphoserine, and serine is associated with changes in the status of membrane phospholipids at low temperatures.

Metabolic Profiling of Fish Meat by GC-MS Analysis, and Correlations with Taste Attributes Obtained Using an Electronic Tongue

“…Because it is a non-proteinous free amino acid, it is detected by analysing extractive components of foodstuffs like seafood, and its content varies depending on the foodstuff [17,18]. In fish, the PEA content in the brain of Perccotts glehni has been reported to vary with the season [19]. However, there are no reports concerning its relationship with the taste of any food.…”

Influence of Low Temperature on the Evolution of Amino Acid Pools Adaptive Modifications inPoikilothermal Animals

“…Pool of РЕА, consisting in the middle of summer only 0,3% of the total FAA pool, at the beginning of winter rising to 33,6% (table 5, Fig 3). PS, which not found in the summer in a free form, at the beginning of winter is 3,75% of the total pool (table 5) [28]. It is also interesting that accumulation of the РЕА has a negative correlation with the content of taurine [27,28].…”

“…The most impressive data are obtained for non-proteinogenic sulphoamino acidtaurine when studying the effect of low temperatures on the adaptation of fish and reptiles [26][27][28][29][30][31][32]. The phenomenon of аdaptive accumulation of taurine (2-amino-ethanesulfonic acid) is found first in our works in examining the impact of seasonal temperature drops or cold shock effect on the pattern of FAA in the eurythermal freshwater fish P. glehni [26][27].…”

“…PS, which not found in the summer in a free form, at the beginning of winter is 3,75% of the total pool (table 5) [28]. It is also interesting that accumulation of the РЕА has a negative correlation with the content of taurine [27,28]. In contrast to the usual increase of taurine level in the blood and organs at low temperatures, in the brain of fishtaurine is declining against the background of increasing levels of РЕА and PS(table 5, Fig 3).…”

“…Unexpected facts were found by us when examining low-temperature responses of the FAA in the brain of eurythermal fresh water fish P. glehni [27,28].It turned out that seasonal decrease in temperature, as well as the effect of cold shock, stimulates the emergence in the fish brain of two new members, РЕА and PS,which are linked to the structure of membrane phospholipids [39][40][41];PEA is a derivative of ethanolamine, and PS is nonproteinogenic amino acid. The appearance of РЕА and PS is specific to the brain of fish because in plasma and in the muscle these amino acids are not detected either in summer or in winter [27].…”