Glycoproteins from the Cuticle of the Atlantic Shore Crab<i>Carcinus maenas</i>: I. Electrophoresis and Western-Blot Analysis by Use of Lectins

Trophic ecology has benefitted from the use of stable isotopes for the last three decades. However, during the last 10 years, there has been a growing awareness of the isotopic biases associated with some pre-analytical procedures that can seriously hamper the interpretation of food webs. We have assessed the extent of such biases by: (1) reviewing the literature on the topic, and (2) compiling C and N isotopic values of marine invertebrates reported in the literature with the associated sample preparation protocols. The factors considered were: acid-washing, distilled water rinsing (DWR), sample type (whole individuals or pieces of soft tissues), lipid content, and gut contents. Two-level ANOVA revealed overall large and highly significant effects of acidification for both delta(13)C values (up to 0.9 per thousand decrease) and delta(15) N values (up to 2.1 per thousand decrease in whole individual samples, and up to 1.1 per thousand increase in tissue samples). DWR showed a weak overall effect with delta(13)C increments of 0.6 per thousand (for the entire data set) or decrements of 0.7 per thousand in delta(15) N values (for tissue samples). Gut contents showed no overall significant effect, whereas lipid extraction resulted in the greatest biases in both isotopic signatures (delta(13)C, up to -2.0 per thousand in whole individuals; delta(15)N, up to +4.3 per thousand in tissue samples). The study analyzed separately the effects of the various factors in different taxonomic groups and revealed a very high diversity in the extent and direction of the effects. Maxillopoda, Gastropoda, and Polychaeta were the classes that showed the largest isotopic shifts associated with sample preparation. Guidelines for the standardization of sample preparation protocols for isotopic analysis are proposed both for large and small marine invertebrates. Broadly, these guidelines recommend: (1) avoiding both acid washing and DWR, and (2) performing lipid extraction and gut evacuation in most cases.

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“…This is a consequence of the high chemical inter-and intra-speciWc heterogeneity of macro-invertebrates (Welinder 1974;Compère et al 2001).…”

Section: Concluding Comments and Recommendations For Standardizationmentioning

confidence: 99%

Effects of sample preparation on stable isotope ratios of carbon and nitrogen in marine invertebrates: implications for food web studies using stable isotopes

et al. 2008

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“…[23,69,70] The Proteins of the cuticle are very diverse and more than 100 different proteins are found. [20,71,72] After formation of the fibril mesh work crystals of calcium or uric acid can be incorporated in the structure and change its physical properties. [73] In crabs and crayfish a substantial part of the cuticle is calcium crystals which give the structure enhanced stiffness.…”

Section: The Cuticle Materialsmentioning

confidence: 99%

Colours and Metallic Sheen in Beetle Shells — A Biomimetic Search for Material Structuring Principles Causing Light Interference

Lenau¹,

Barfoed²

2008

Adv Eng Mater

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Visual aesthetic has always played a vital role for the success of many products. This includes colours and glossiness and metal appearance which is often achieved using surface coatings. Present coating techniques do, however, have limitations. It is difficult to reach very bright and brilliant colours, colours tend to fade over time and many of the materials and coating technologies pollute and have other environmental problems. Beetles in nature have many of the desired properties: They have appealing brilliant colours and some even with metallic appearance. It is noticeable that the colours are long lasting as some of the beetles we have studied at the zoological museum are more than 200 years old and have colours and brightness as if they were still alive. Furthermore, the beetles in nature are part of sustainable ecosystems, which means that they are made from renewable materials that are broken down and recycled when the beetle dies. Beetles also possess another and very attractive property: Their metallic look originates from structures in organic materials which is both electrically and thermal insulating. The industrial perspective is to be able to manufacture products with attractive metallic surfaces that do not feel so cold to touch as their metallic counterparts and that do not represent an electrical shock hazard.

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“…These pre-molt changes in the existing cuticle relate to mineral dissolution and resorption rather than mineral deposition. Various mild aqueous solvents were used to extract glycoproteins from the anecdysial (intermolt) cuticle of the Atlantic shore crab Carcinus maenas, and the complex array of electrophoretic bands described from these extracts contained both O-linked and N-linked glycans (Compère et al, 2002). Fluctuations were observed in both soluble protein and carbohydrate during the molt cycle in the mud crab Scylla serrata, but no electrophoretic fractionation was performed to observe changes in individual glycoproteins (Pratoomchat et al, 2002).…”

mentioning

confidence: 99%

Purification of a soluble glycoprotein from the uncalcified ecdysial cuticle of the blue crabCallinectes sapidusand its possible role in initial mineralization

Tweedie

Coblentz

Shafer

2004

Journal of Experimental Biology

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A heavily glycosylated soluble protein was purified using a combination of lectin affinity and size exclusion chromatography from a soluble extract of uncalcified dorsal cuticle of blue crab Callinectes sapidus removed at ecdysis. Similarities in apparent molecular mass and carbohydrate composition suggest that this protein is the same species previously shown to disappear from soluble extracts coincidentally with the onset of mineral deposition in the newly exposed post-molt cuticle. The amino acid sequence of the N-terminal portion of the core polypeptide was determined and polyclonal antibodies were raised against both the purified glycoprotein and the peptide. Immunoblots of unfractionated soluble extracts taken at various times post-molt illustrated that the antipeptide antibody recognized several polypeptides with electrophoretic mobilities that differ from the purified glycoprotein. These bands may be deglycosylation products which would not have been purified due to different lectin affinity or size. Immunohistochemical analysis indicated uniform protein distribution in the exocuticle at ecdysis, but decreased antibody binding at the interprismatic septa by 2·h post-molt. The location of the protein is therefore the negative image of the calcification pattern in the exocuticle and provides a spatial pattern to correlate with the previously reported temporal events. This strengthens the hypothesis that the glycoprotein under investigation is an inhibitor of calcite nucleation or of initial amorphous calcium carbonate accumulation.

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Glycoproteins from the Cuticle of the Atlantic Shore CrabCarcinus maenas: I. Electrophoresis and Western-Blot Analysis by Use of Lectins

Cited by 16 publications

References 65 publications

Effects of sample preparation on stable isotope ratios of carbon and nitrogen in marine invertebrates: implications for food web studies using stable isotopes

Effects of sample preparation on stable isotope ratios of carbon and nitrogen in marine invertebrates: implications for food web studies using stable isotopes

Colours and Metallic Sheen in Beetle Shells — A Biomimetic Search for Material Structuring Principles Causing Light Interference

Purification of a soluble glycoprotein from the uncalcified ecdysial cuticle of the blue crabCallinectes sapidusand its possible role in initial mineralization

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