کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2840570 1165332 2013 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Fatty acid modifications during autumnal cold-hardening in an obligatory ectoparasite, the deer ked (Lipoptena cervi)
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش حشره شناسی
پیش نمایش صفحه اول مقاله
Fatty acid modifications during autumnal cold-hardening in an obligatory ectoparasite, the deer ked (Lipoptena cervi)
چکیده انگلیسی


• The deer ked is an abundant obligatory ectoparasite of cervids.
• Deer keds can survive temperatures as low as −15 °C.
• They have high proportions of PUFA in late autumn for survival in cold.
• Increased unsaturation may allow lipid membranes to maintain sufficient fluidity.
• The deer ked may have the ability of synthesizing, e.g., 18:2n-6 de novo.

Poikilothermic organisms often modify their tissue fatty acids (FA) in response to cold exposure by increased unsaturation. In insects, this has been found to be accompanied by increases in the activities or mRNA expression of desaturase enzymes. In the present study, the FA composition of an obligatory ectoparasite, the deer ked (Lipoptena cervi), was analyzed in August–November. In addition to studying the general FA profile of the species, the possible contribution of FA to autumnal cold-hardening was examined. The FA composition of the deer ked imago was relatively similar to previously studied dipteran species, with high percentages of monounsaturated FA (especially 18:1n-9 and 16:1n-7) and 16:0. The individuals caught later in autumn had significantly higher values for the ratio of unsaturated to saturated FA and, regarding individual FA, the percentages of 18:1n-9, 18:2n-6, 18:3n-3, 20:4n-6 and 22:6n-3 were higher but those of 16:0 and 16:1n-7 lower than in August. Potential selective use of particular FA for energy could not account for the large increase in the levels of polyunsaturated FA (PUFA). The observed increased degree of FA unsaturation may have resulted from cold-induced desaturation, as observed previously in other species, or increased survival of the keds with relatively large PUFA contents. The PUFA with low melting points probably allow lipid membranes to maintain sufficient fluidity required to maintain protein functions at low ambient temperatures.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Insect Physiology - Volume 59, Issue 6, June 2013, Pages 631–637
نویسندگان
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