Search

Background In our previous studies, we demonstrated that the accumulation of carotenoids in QN Orange scallops might be regulated by the vacuolar protein sorting 29 ( VPS29) gene. VPS genes are involved in pigments accumulation (including carotenoids) in some species and VPS29 is known as the core component of the membrane transport complex Retromer . However, the possible mechanism of carotenoids accumulation underlying the VPS29 remains unexplored. This study aimed to further elucidate the roles of VPS29 in the carotenoid deposition. Results Transcriptomic analyses revealed four differentially expressed genes related to carotenoid accumulation, including three down-regulated genes, low-density lipoprotein receptor domain class, scavenger receptor , Niemann Pick C1-like 1, and one up-regulated gene, ATP binding cassette transporter in RNAi group. Results from metabonomic analyses indicated increased profiles of retinol and decreased fatty acids between the RNAi and the control group. Conclusions It thus speculated that VPS may be related to the accumulation of carotenoids as RNAi of VPS 29 seemed to result in a reduction in pectenolone through the blockage in the absorption of carotenoids and an accelerated cleavage of carotenoids into retinol.

Microplastics are ubiquitous in the environment, sediments in the water body are considered as the sink of microplastics, but its accumulation and change trend have received little attention. We assessed the concentrations of microplastics in sediment samples collected in Wuliangsuhai Lake. The abundance of microplastics (0–6 cm) in surface sediment ranged from 16.5 to 72.4 particles 100 g−1 dry weight. The results show that the abundance, type and size of microplastics in surface sediment of different functional areas are different. Four sampling points were selected to investigate the vertical distribution of microplastics. The abundance of microplastics exhibited a clear decreasing trend with increased sediment depth, the abundance of microplastics in deep sediments is much less. This result shows that when estimating the storage of microplastics in sediments, if only considered the surface sediments, the assessment of microplastic storage worldwide might be underestimated.

Background In our previous studies, we selected a new scallop strain, QN Orange, which is rich in carotenoids in its adductor muscles, from the bay scallop-Peruvian scallop hybrids. We further demonstrated that the accumulation of carotenoids in QN Orange scallops might be regulated by a series of genes among which the vacuolar protein sorting 29 ( VPS29) gene may play a pivotal role in carotenoid metabolism. However, the possible mechanism underlying the VSP29 remains unexplored. This study aimed to further elucidate the role of VPS29 in the carotenoid deposition process via RNA interference (RNAi).Results HPLC results showed that the pectenolone, but not pectenoxanthin content in the adductor muscle was reduced by RNAi of VSP29 . Transcriptomic analyses revealed 534 differentially expressed genes (DEGs) between the group treated with RNAi and the control group, including genes related to carotenoid biosynthesis such as low-density lipoprotein receptor domain class, cytochrome P450, Niemann Pick C1-like 1, and ATP binding cassette transporter. KEGG analyses further indicated that lysosome pathway was enriched with VPS29 RNAi.Conclusions Our results indicated that VPS29 may be crucial in carotenoid deposition through the regulation of other genes related to carotenoid metabolism. This study will provide a theoretical basis and a new research perspective for revealing the mechanism of carotenoid accumulation in shellfish.

Shell color polymorphism is common in nature for the marine mollusks. The Pacific oyster Crassostrea gigas, is widely cultured and one of the most economically important bivalve species with various shell color variants. Here, a total of 1061 single nucleotide polymorphism markers, developed from expressed sequence tags (EST-SNPs), were used to construct two genetic linkage maps based on reciprocal-cross between black shell and white shell oysters (MF-A and MF-B) respectively. The two separate linkage maps were combined into an integrated map spanning 947.31 cM in total length. The integrated map was composed of 351 EST-SNP markers distributing on 10 linkage groups, with an average interval of 2.78 cM between adjacent markers. For the MF-A, 11 quantitative trait loci (QTLs) for shell color traits and five QTLs for growth traits were detected, explaining 8.1%–13.8% (mean = 11.76%) and 10.4%–11.0% (mean = 10.66%) phenotypic variance respectively. For the MF-B, nine QTLs for shell color traits and eight QTLs for growth traits were detected, explaining 8.8%–21.7% (mean = 12.84%) and 8.4%–9.4% (mean = 8.88%) phenotypic variance respectively. QTLs clustering was found on the linkage group 2 of the MF-A and the linkage group 8 of the MF-B, and the QTLs showed that pleiotropism could affect at most three traits. Three shared-QTLs associated with shell color traits were identified on the integrated map, and one of them (qA-a* 4) was significantly homologous to C. gigas calmodulin-like protein. The QTLs identified in the present study could be useful in finding candidate genes for the shell color and growth-related traits in future, and potentially applied to marker-assisted selection breeding programs for C. gigas.

There is an increasing requirement for traceability of aquaculture products, both for consumer protection and for food safety. There are high error rates in the conventional traceability systems depending on physical labels. Genetic traceability technique depending on DNA-based tracking system can overcome this problem. Genealogy information is essential for genetic traceability, and microsatellite DNA marker is a good choice for pedigree analysis. As increasing genotyping throughput of microsatellites, microsatellite multiplex PCR has become a fast and cost-effective technique. As a commercially important cultured aquatic species, Pacific oyster Crassostrea gigas has the highest global production. The objective of this study was to develop microsatellite multiplex PCR panels with dye-labeled universal primer for pedigree analysis in C. gigas, and these multiplex PCRs were validated using 12 full-sib families with known pedigrees. Here we developed six informative multiplex PCRs using 18 genomic microsatellites in C. gigas. Each multiplex panel contained a single universal primer M13(−21) used as a tail on each locus-specific forward primer and a single universal primer M13(−21) labeled with fluorophores. The polymorphisms of the markers were moderate, with an average of 10.3 alleles per locus and average polymorphic information content of 0.740. The observed heterozygosity per locus ranged from 0.492 to 0.822. Cervus simulations revealed that the six panels would still be of great value when massive families were analysed. Pedigree analysis of real offspring demonstrated that 100% of the offspring were unambiguously allocated to their parents when two multiplex PCRs were used. The six sets of multiplex PCRs can be an important tool for tracing cultured individuals, population genetic analysis, and selective breeding program in C. gigas.

The shell color of the Pacific oyster (Crassostrea gigas) is a desirable trait, but only a few genetic studies on shell color have been documented. Through successive selective breeding, four shell color variants of white (W), gold (G), black (B) and purple (P) C. gigas have been developed. The amplified fragment length polymorphism (AFLP) technique was used to scan the genomes of the four variants with different shell colors and one wild population (C) to identify candidate markers for shell polymorphism. Fifteen AFLP primer combinations were used, 1079 loci were scored as polymorphic loci, and the percentage of polymorphic bands was 95.5%. In the gold, white, black, purple and wild populations, the percentages of polymorphic loci were estimated to be 90.5% (G), 90.0% (W), 91.1% (B), 95.3% (P) and 93.2% (C); the expected heterozygosity values were 0.3115 (G), 0.3044 (W), 0.3102 (B), 0.3285 (P) and 0.3105 (C). The white shell variant was observed to have slightly lower genetic diversity than others, with a FST value of 0.1483. These results indicated that the four different shell color variants had high genetic diversity and that the genetic differentiation of populations mostly results from genetic diversity of individuals within populations. Furthermore, 11 outlier loci were considered candidate markers for shell color. This work provides new insights on relationships among color variants of C. gigas.

The Cu, Co codoped ZnO multilayer films were deposited by magnetron sputtering on silicon (100) in different sputtering gas and the substrates were held at 500 °C. The oxygen content in the films were correlated with the oxygen prevailed in the sputter chamber. The influences of the oxygen content in the sputtering gas on structural, optical and magnetic properties of Cu, Co codoped ZnO multilayer films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, UV absorption spectrophotometer and vibrating sample magnetometer. The results indicated that Cu2+ and Co2+ ions would uniformly substitute into the Zn2+ sites of ZnO lattice. The optical band gap of the films increased from 3.14 to 3.23 eV with increasing oxygen content of the sputtering gas. Oxygen concent have effected on the ferromagnetism of the samples.

Table S1. Summary of RNA-seq results. (DOCX 31 kb)

Table S2. Basic characteristic of reads mapping to the reference genome. (DOCX 19 kb)

The influence of substrate curvature on structural, optical properties of Cu, Co codoped ZnO thin films were investigated in this study. XRD analysis indicated that the crystal quality of the ZnO films could been influenced by the substrate curvature. The biaxial stress of our samples was measured by side-inclination X-ray diffraction technique. The results indicated that the type of the stress was biaxial compressive stress. Optical absorption spectra showed the absorption edge of our samples displayed blueshift with decreasing substrate curvature. Gauss fit for PL emission spectra showed that the substrate curvature affected the PL properties of the Cu, Co codoped ZnO thin films deposited on polystyrene particles. The various substrates induced defect-related emission increased in visible region.

A series of Cu and Co codoped ZnO thin films with different Cu content were prepared using the RF magnetron sputtering method. The XRD results indicated that the crystal quality of the ZnO films were influenced by the level of Cu-doping during the sputtering process. X-ray photoelectron spectroscopy was used to detect the elemental valence states of Zn, Co, Cu and O. Magnetic measurements showed that the Cu and Co codoped ZnO thin films displayed room temperature ferromagnetism. The enhanced FM in the Cu, Co codoped ZnO can be attributed to the 3d orbitals split of Cu2+. The results of the absorption spectra showed that the bandgap of the ZnO thin films narrow down caused by the Cu doping. It also can be attributed to 3d orbitals split which further supported our interpretation of magnetic.

Golden shell color and mineral content are important economic traits of Pacific oyster (Crassostrea gigas). In this study, we mapped a series of quantitative trait loci (QTLs) that control zinc (Zn) and magnesium (Mg) content, shell color and growth performance to two sex-averaged linkage maps from the FAM-A and FAM-B families. In total, ten QTLs were identified in seven linkage groups (LGs) in the FAM-B family, and seven QTLs were identified in four linkage groups in the FAM-A family. Two QTLs affecting the trait of golden shell color were identified in LG8 of the FAM-A and LG10 of the FAM-B families, which could explain 20.2 and 10.5% of the phenotypic variations, respectively. Two QTLs for Zn content were identified that could contribute to 17.9 and 34.44% of the phenotypic variations in FAM-A. Six QTLs for Zn and Mg contents were identified in four LGs (LG1, LG2, LG5, and LG9) in FAM-B, which explained 13.5-26.7% of the phenotypic variations. In addition, seven QTLs related to oyster growth were recognized in both FAM-A and FAM-B families accounting for 14.6-36.7% of the phenotypic variations. All of the DNA markers in QTL regions were blasted and 14 genes associated with above traits were identified. The mRNA expression of these genes was determined by quantitative RT-PCR. These QTLs and candidate genes could be used as potential targets for marker-assisted selection in C. gigas breeding.

Color polymorphism is relatively common in marine mollusks. Shell color affects the visual perception of products which, consequently, influences consumer preference and product value. To increase the value of the Pacific oyster (Crassostrea gigas ) for the half-shell market, four shell color strains (golden, white, purple, and black) of C. gigas have been developed through successive selective breeding. To investigate genetic variation and identify breeding signatures of C. gigas , the four shell color strains and three wild populations were assessed through using 133 single nucleotide polymorphism (SNP) markers. The genetic diversity analysis demonstrated that the shell color strain exhibited significant reduction in observed number of alleles in comparison with the wild population. However, there is no significant differences of observed heterozygosity and expected heterozygosity were identified among the seven populations. Based on three outlier tests, a total of 16 loci were identified under selection, and four common outlier loci (CgSNP82, CgSNP273, CgSNP646, and CgSNP1131) were detected based on all the methods. FST values showed significant genetic differentiation between shell color strains, as well as between shell color strains and wild populations. The information on the genetic variation and differentiation in shell color strains and wild populations of C. gigas is useful for setting up suitable guidelines for founding and maintaining of cultured stocks. The detected loci might benefit the breeding programs after being tested.

low noise amplifiers are the key components of the receiver front end, it has been widely used in microwave communication, radar, electronic warfare, and a variety of high-precision microwave measurement system and its performance directly affects the performance of entire receiving system, so it is essential to develop excellent low noise amplifier. In this paper, it has designed a LNA which has good performances at 2GHz. The measurement results performs a high gain (>15dB), fine flatness(