Relating RNA:DNA ratio in Eurytemora affinis to seston fatty acids in a highly dynamic environment

The skin is a flexible organ that forms a barrier between the environment and the body's interior; it is involved in the immune response, in protection and regulation, and is a dynamic environment in which skin lipids play an important role in maintaining homeostasis. The different layers of the skin differ in both the composition and amount of lipids. The epidermis displays the best characteristics in this respect. The main lipids in this layer are cholesterol, fatty acids (FAs) and ceramides. FAs can occur in free form and as components of complex molecules. The most poorly characterized FAs are very long-chain fatty acids (VLCFAs) and ultra long-chain fatty acids (ULCFAs). VLCFAs and ULCFAs are among the main components of ceramides and are part of the free fatty acid (FFA) fraction. They are most abundant in the brain, liver, kidneys, and skin. VLCFAs and ULCFAs are responsible for the rigidity and impermeability of membranes, forming the mechanically and chemically strong outer layer of cell membranes. Any changes in the composition and length of the carbon chains of FAs result in a change in their melting point and therefore a change in membrane permeability. One of the factors causing a decrease in the amount of VLCFAs and ULCFAs is an improper diet. Another much more important factor is mutations in the genes which code proteins involved in the metabolism of VLCFAs and ULCFAs—regarding their elongation, their attachment to ceramides and their transformation. These mutations have their clinical consequences in the form of inborn errors in metabolism and neurodegenerative disorders, among others. Some of them are accompanied by skin symptoms such as ichthyosis and ichthyosiform erythroderma. In the following review, the structure of the skin is briefly characterized and the most important lipid components of the skin are presented. The focus is also on providing an overview of selected proteins involved in the metabolism of VLCFAs and ULCFAs in the skin.

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Negligible effects of ocean acidification on <i>Eurytemora affinis</i> (Copepoda) offspring production

Biogeosciences ◽

10.5194/bg-13-1037-2016 ◽

2016 ◽

Vol 13 (4) ◽

pp. 1037-1048 ◽

Cited By ~ 10

Author(s):

Anna-Karin Almén ◽

Anu Vehmaa ◽

Andreas Brutemark ◽

Lennart Bach ◽

Silke Lischka ◽

...

Keyword(s):

Fatty Acids ◽

Ocean Acidification ◽

Chlorophyll A ◽

Monounsaturated Fatty Acids ◽

Eurytemora Affinis ◽

Physiological Level ◽

Chlorophyll A Concentration ◽

Offspring Production ◽

The Baltic ◽

Positive Effect

Abstract. Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during 4 consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration and dinoflagellate biomass, had a positive effect. The concentration of polyunsaturated fatty acids in the females was reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

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Negligible effects of ocean acidification on <i>Eurytemora affinis</i> (Copepoda) offspring production

Biogeosciences Discussions ◽

10.5194/bgd-12-17093-2015 ◽

2015 ◽

Vol 12 (20) ◽

pp. 17093-17123 ◽

Cited By ~ 4

Author(s):

A.-K. Almén ◽

A. Vehmaa ◽

A. Brutemark ◽

L. Bach ◽

S. Lischka ◽

...

Keyword(s):

Fatty Acids ◽

Ocean Acidification ◽

Chlorophyll A ◽

Monounsaturated Fatty Acids ◽

Eurytemora Affinis ◽

Physiological Level ◽

Chlorophyll A Concentration ◽

Offspring Production ◽

The Baltic ◽

Positive Effect

Abstract. Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during four consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration, had a strong positive effect. The concentration of polyunsaturated fatty acids in the females were reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

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