Labroides dimidiatus has been proven to remove ectoparasites and monogeneans from client fishes and studies showed that they were not infected with the parasite. Due to this, there is a possibility that a defense mech...Labroides dimidiatus has been proven to remove ectoparasites and monogeneans from client fishes and studies showed that they were not infected with the parasite. Due to this, there is a possibility that a defense mechanism against pathogen and parasitic invasion exist in the epidermal mucus which serves as a mechanical as well as biochemical barrier. The study was performed to identify the amino acid and fatty acid components using GC （gas chromatography） and HPLC （high performance liquid chromatography） in epidermal mucus ofL. dimidiatus. The present study revealed 16 components of amino acid and 22 types of fatty acid in epidermal mucus ofL. dimidiatzts. Linoleic acid （C18：2n6c） was the most prominent PUFA （polyunsaturated fatty acid） which contributed approximately 11.69% of total fatty acids. The other major fatty acids are palmitic acid （C 16：0）, oleic acid （C 18： l n9c）, linoledaidic acid （C18：2n6t）, arachidic acid （C20：0）, Gamma-Linoleic acid （C18：3n6） and gadoleic acid （C20：1） which contained reasonable amounts of 9.52%, 8.06%, 6.26%, 8.33%, 6.21% and 9.05% of total fatty acids, respectively. This present study also demonstrated the presence of various amino acids in skin extract. Glycine, glutamine, arginine, asparagin and alanine were found at high concentration of 8.09%, 6.95%, 5.73%, 4.74%, 4.58% respectively. The most abundance percentage of linoleic acid （C18：2n6c） was found to be the metabolic precursor of arachidonic acid （AA） which inducing platelet aggregation, facilitate the blood clotting process and adhesion in endothelial cells during wound healing and might be responsible for rapid tissue growth in L. dimidiatus. It can be concluded that the amino acid and fatty acid profile from the epidermal mucus ofL. dimidiatus contains most of the essential components required to play a possible role in its defense mechanism. Understanding the biochemical properties of L. dimidiatus epidermal mucus in defense mechanism would enable to determine how this fish protect itself from parasitic infection.展开更多
Hummingbird migration is a remarkable feat, given the small body sizes of migratory species, their high metabolic rates during flight and the long distances traveled using fat to fuel the effort. Equally remarkable is...Hummingbird migration is a remarkable feat, given the small body sizes of migratory species, their high metabolic rates during flight and the long distances traveled using fat to fuel the effort. Equally remarkable is the ability of premigratory hummingbirds in the wild to accumulate fat, synthesized from sugar, at rates as high as 10% of body mass per day. This paper summarizes, using Rumsfeldian terminology, ＂known knowns＂ concerning the energetics of hummingbird migration and premi- gratory fattening. Energy metabolism during hover-feeding on floral nectar is fueled directly by dietary sugar through the path- way recently named the ＂sugar oxidation cascade＂. However, flight without feeding for more than a few minutes requires shifting to fat as a fuel. It is proposed that behavior and metabolic fuel choice are coadapted to maximize the rate of fat deposition during premigratory fattening. The hummingbird liver appears to possess extraordinarily high capacities for fatty acid synthesis. The analysis of ＂known knowns＂ leads to identification of ＂known unknowns＂, e.g., the fates of dietary glucose and fructose, the regulation of fat metabolism and metabolic interactions between liver and adipose tissue. The history of science behooves recog- nition of ＂tmknown unknowns＂ that, when discovered serendipitously, might shed new light on fundamental mechanisms as well as human pathological conditions .展开更多
文摘Labroides dimidiatus has been proven to remove ectoparasites and monogeneans from client fishes and studies showed that they were not infected with the parasite. Due to this, there is a possibility that a defense mechanism against pathogen and parasitic invasion exist in the epidermal mucus which serves as a mechanical as well as biochemical barrier. The study was performed to identify the amino acid and fatty acid components using GC （gas chromatography） and HPLC （high performance liquid chromatography） in epidermal mucus ofL. dimidiatus. The present study revealed 16 components of amino acid and 22 types of fatty acid in epidermal mucus ofL. dimidiatzts. Linoleic acid （C18：2n6c） was the most prominent PUFA （polyunsaturated fatty acid） which contributed approximately 11.69% of total fatty acids. The other major fatty acids are palmitic acid （C 16：0）, oleic acid （C 18： l n9c）, linoledaidic acid （C18：2n6t）, arachidic acid （C20：0）, Gamma-Linoleic acid （C18：3n6） and gadoleic acid （C20：1） which contained reasonable amounts of 9.52%, 8.06%, 6.26%, 8.33%, 6.21% and 9.05% of total fatty acids, respectively. This present study also demonstrated the presence of various amino acids in skin extract. Glycine, glutamine, arginine, asparagin and alanine were found at high concentration of 8.09%, 6.95%, 5.73%, 4.74%, 4.58% respectively. The most abundance percentage of linoleic acid （C18：2n6c） was found to be the metabolic precursor of arachidonic acid （AA） which inducing platelet aggregation, facilitate the blood clotting process and adhesion in endothelial cells during wound healing and might be responsible for rapid tissue growth in L. dimidiatus. It can be concluded that the amino acid and fatty acid profile from the epidermal mucus ofL. dimidiatus contains most of the essential components required to play a possible role in its defense mechanism. Understanding the biochemical properties of L. dimidiatus epidermal mucus in defense mechanism would enable to determine how this fish protect itself from parasitic infection.
基金I am deeply grateful to EW. Hochachka, C.L. Gass, K.C. Welch, Jr., J.R.B. Lighton, C. Martinez del Rio and O. Mathieu-Costello for their contributions to the research that led to the ideas presented and questions raised in this paper. Research on which this article is based was funded by the U.S. National Science Foundation （IOB 0517694）.
文摘Hummingbird migration is a remarkable feat, given the small body sizes of migratory species, their high metabolic rates during flight and the long distances traveled using fat to fuel the effort. Equally remarkable is the ability of premigratory hummingbirds in the wild to accumulate fat, synthesized from sugar, at rates as high as 10% of body mass per day. This paper summarizes, using Rumsfeldian terminology, ＂known knowns＂ concerning the energetics of hummingbird migration and premi- gratory fattening. Energy metabolism during hover-feeding on floral nectar is fueled directly by dietary sugar through the path- way recently named the ＂sugar oxidation cascade＂. However, flight without feeding for more than a few minutes requires shifting to fat as a fuel. It is proposed that behavior and metabolic fuel choice are coadapted to maximize the rate of fat deposition during premigratory fattening. The hummingbird liver appears to possess extraordinarily high capacities for fatty acid synthesis. The analysis of ＂known knowns＂ leads to identification of ＂known unknowns＂, e.g., the fates of dietary glucose and fructose, the regulation of fat metabolism and metabolic interactions between liver and adipose tissue. The history of science behooves recog- nition of ＂tmknown unknowns＂ that, when discovered serendipitously, might shed new light on fundamental mechanisms as well as human pathological conditions .
