BackgroundThe noble scallop Chlamys nobilis Reeve displays polymorphism in shell and muscle colors. Previous research showed that the orange scallops with orange shell and muscle had a significantly higher carotenoid content than the brown ones with brown shell and white muscle. There is currently a need to identify candidate genes associated with carotenoid-based coloration.ResultsIn the present study, 454 GS-FLX sequencing of noble scallop transcriptome yielded 1,181,060 clean sequence reads, which were assembled into 49,717 isotigs, leaving 110,158 reads as the singletons. Of the 159,875 unique sequences, 11.84% isotigs and 9.35% singletons were annotated. Moreover, 3,844 SSRs and over 120,000 high confidence variants (SNPs and INDELs) were identified. Especially, one class B scavenge receptor termed SRB-like-3 was discovered to express only in orange scallops and absent in brown ones, suggesting a significant association with high carotenoid content. Down-regulation of SRB-like-3 mRNA by RNA interference remarkably decreased blood carotenoid, providing compelling evidence that SRB-like-3 is an ideal candidate gene controlling carotenoid deposition and determining orange coloration.ConclusionTranscriptome analysis of noble scallop reveals a novel scavenger receptor significantly associated with orange scallop rich in carotenoid content. Our findings pave the way for further functional elucidation of this gene and molecular basis of carotenoid deposition in orange scallop.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1241-x) contains supplementary material, which is available to authorized users.

Carotenoids are biologically active pigments that are well-known to enhance the defense and immunity of the vertebrate system. However, in invertebrates, the role of carotenoids in immunity is not clear. Therefore, this study aims to review the scientific evidence for the role of carotenoids in invertebrate immunization. From the analysis of published literatures and recent studies from our laboratory, it is obvious that carotenoids are involved in invertebrate immunity in two ways. On the one hand, carotenoids can act as antioxidant enzymes to remove singlet oxygen, superoxide anion radicals, and hydroxyl radicals, thereby reducing SOD activity and reducing the cost of immunity. In some organisms, carotenoids have been shown to promote SOD activity by up-regulating the expression of the ZnCuSOD gene. Carotenoids, on the other hand, play a role in the expression and regulation of many genes involved in invertebrate immunity, including thioredoxins (TRX), peptidoglycan recognition receptor proteins (PGRPs), ferritins, prophenoloxidase (ProPO), vitellogenin (Vg), toll-like receptor (TLRs), heat shock proteins (HSPs), and CuZnSOD gene. The information in this review is very useful for updating our understanding of the progress of carotenoid research in invertebrate immunology and to help identify topics for future topics.

Knots and links have been conjectured to play a fundamental role in a wide range of scientific fields. Recently, tying isolated vortex knots in the complex optical field has been realized. However, how to construct the acoustic vortex knot is still an unknown problem. Here we propose theoretically and demonstrate experimentally the creation of acoustic vortex knots using metamaterials, with decoupled modulation of transmitted phase and amplitude. Based on the numerical simulation, we find that the knot function can be embedded into the acoustic field by designed metamaterials with only 24 × 24 pixels. Furthermore, using the optimized metamaterials, the acoustic fields with Hopf link and trefoil knot vortex lines have been observed experimentally.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential in important physiological processes. However, the endogenous PUFA biosynthesis pathway is poorly understood in marine bivalves. Previously, a fatty acyl desaturase (Fad) with Δ5 activity was functionally characterized and an elongase termed Elovl2/5 was reported to efficiently elongate 18:2n-6 and 18:3n-3 to 20:2n-6 and 20:3n-3 respectively in Chlamys nobilis. In this study, another elongase and another Fad were identified. Functional characterization in recombinant yeast showed that the newly cloned elongase can elongate 20:4n-6 and 20:5n-3 to C22 and C24, while the newly cloned scallop Fad exhibited a Δ8-desaturation activity, and could desaturate exogenously added PUFA 20:3n-3 and 20:2n-6 to 20:4n-3 and 20:3n-6 respectively, providing the first compelling evidence that noble scallop could de novo biosynthesize 20:5n-3 and 20:4n-6 from PUFA precursors though the "Δ8 pathway". No Δ6 or Δ4 activity was detected for this Fad. Searching against our scallop transcriptome database failed to find any other Fad-like genes, indicating that noble scallop might have limited ability to biosynthesize 22:6n-3. Interestingly, like previously characterized Elovl2/5, the two newly cloned genes showed less efficient activity toward n-3 PUFA substrates than their homologous n-6 substrates, resulting in a relatively low efficiency to biosynthesize n-3 PUFA, implying an adaption to marine environment.

Bivalve molluscs are very nutritious and are an important source of human animal protein. To date, bivalve farming has contributed to about 15% of the mean per capita animal protein intake of approximate 1.5 billion people around the world. Unfortunately, the effects of climate change, mainly global warming and ocean acidification, have had many deleterious effects on bivalve aquaculture, not only leading to mass mortalities of bivalves in farms and hatcheries, but also causing collapse of natural bivalve populations. In response to the recurrent mass mortalities of farmed bivalves, many selective breeding programmes have been launched with the breeding goal of reducing mortality rate caused by disease outbreaks and changing ocean conditions. This article reviews the progress and potential of selective breeding of edible bivalves in the context of global climate change. It is clear from the literature that in terms of environmental sensitivity, and disease resistance and tolerance, selective breeding has great potential for improving the robustness of edible bivalves with significant heritability and genetic gain. Because the robustness of edible bivalves to climate change is a complex trait affected by multiple genes, the application of modern genomic tools in selective breeding is expected to dramatically enhance the accuracy and efficacy of genetic improvements and produce bivalve strains that are robust to climate change. The information in this article is very useful for guidance on adaptation strategies for climate‐smart bivalve aquaculture solutions to be implemented in bivalve hatcheries and farms.

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Dielectric polyimides (PIs) are ubiquitous as insulation in electrical power systems and electronic devices. Generally, dynamic polyimide is required to solve irreversible failure processes of electrical or mechanical damage, for example, under high temperature, pressure, and field strength. The challenge lies in the design of the molecular structure of rigid polyimide to achieve dynamic reversibility. Herein, a low‐molecular‐weight polyimide gene unit is designed to crosslink with polyimide ligase to prepare the smart film. Interestingly, due to the variability of gene unit and ligase combinations, the polyimide films combining hardness with softness are designed into three forms via a “Mimosa‐like” bionic strategy to adapt to different application scenarios. Meanwhile, the films have good degradation efficiency, excellent recyclability, and can be self‐healable, which makes them reuse. Clearly, the films can be used in the preparation of ultrafast sensors with a response time ≈0.15 s and the application of corona‐resistant films with 100% recovery. Furthermore, the construction of polyimide and carbon‐fiber‐reinforced composites (CFRCs) has been verified to apply to the worse environment. Nicely, the composites have the property of multiple cycles and the non‐destructive recycle rate of carbon fiber (CF) is as high as 100%. The design idea of preparing high‐strength dynamic polyimide by crosslinking simple polyimide gene unit with ligase could provide a good foundation and a clear case for the sustainable development of electrical and electronic polyimides, from the perspective of Mimosa bionics.

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