期刊
JOURNAL OF EXPERIMENTAL BIOLOGY
卷 216, 期 7, 页码 1235-1243出版社
COMPANY OF BIOLOGISTS LTD
DOI: 10.1242/jeb.075531
关键词
cryptobiosis; inorganic ions; ion chromatography; nanoliter osmometry; organic osmolytes; tardigrade
类别
资金
- Carlsberg Foundation
- Freja-Programme (Faculty of Science, University of Copenhagen)
Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content indicates that Na+ and Cl- are the principal inorganic ions in tardigrade fluids, albeit other ions, i.e. K+, NH4+, Ca2+, Mg2+, F-, SO42- and PO43- were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared with that of the external medium (Na+, x70-800; K+, x20-90; Ca2+ and Mg2+, x30-200; F-, x160-1040, Cl-, x20-50; PO43-, x700-2800; SO42-, x30-150). In contrast, in the marine species H. crispae, Na+, Cl- and SO42- are almost in ionic equilibrium with (brackish) salt water, while K+, Ca2+, Mg2+ and F- are only slightly concentrated (x2-10). An anion deficit of similar to 120 mEq l(-1) in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361 +/- 49. mOsm kg(-1) in R. coronifer to 961 +/- 43 mOsm kg(-1) in H. crispae. Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified organic osmolytes, the identification of which is expected to provide increased insight into the phenomenon of cryptobiosis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据