123 research outputs found

    Fatty acid analysis reveals the trophic interactions among organisms in the Zhelin Bay Marine Ranch

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    The fatty acid composition in organisms can reflect the trophic level, feeding habits, and utilization of local resources. In the present study, the living resources of different functional areas (artificial reef area, shellfish area, macroalgae area) in the Zhelin Bay Marine Ranch were investigated, and fatty acid analysis was used to elucidate the trophic relations across the food web. The results showed that 22:6ω3 FA (docosahexaenoic acid, DHA), 20:5ω3 FA (eicosapentaenoic acid, EPA), 16:1ω7 FA, and 16:0 FA are fatty acid biomarkers that distinguish carnivorous, omnivorous, and herbivorous organisms. The ratios of DHA/EPA, polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA), and sum of ω3 fatty acids/sum of ω6 fatty acids (Σω3/Σω6) can be used as an important basis to assess the trophic level and feeding habits of organisms. In the comparison of the food web structure of different functional areas, the DHA/EPA ratio of carnivorous organisms in the Artificial Reef area was higher than that in other functional areas due to the abundant living resources, indicating that the food web of the Artificial Reef area presents lower stability to cope with perturbations. Furthermore, MixSIAR was used to quantitatively estimate the diet composition of consumers in the Zhelin Bay Marine Ranch based on their fatty acids. The results of the present study are a valuable contribution to understanding the trophic relationships in the Zhelin Bay Marine Ranch and provide theoretical support for future planning and construction of marine ranches

    Polarization-Engineering in III-V Nitride Heterostructures: New Opportunities For Device Design

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    The role of spontaneous and piezoelectric polarization in III-V nitride heterostructure devices is discussed. Problems as well as opportunities in incorporating polarization in abrupt and graded heterojunctions composed of binary, ternary, and quaternary nitrides are outlined.Comment: 7 pages, 5 figure

    A Rapid and Sensitive Europium Nanoparticle-Based Lateral Flow Immunoassay Combined with Recombinase Polymerase Amplification for Simultaneous Detection of Three Food-Borne Pathogens

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    Food-borne pathogens have become an important public threat to human health. There are many kinds of pathogenic bacteria in food consumed daily. A rapid and sensitive testing method for multiple food-borne pathogens is essential. Europium nanoparticles (EuNPs) are used as fluorescent probes in lateral flow immunoassays (LFIAs) to improve sensitivity. Here, recombinase polymerase amplification (RPA) combined with fluorescent LFIA was established for the simultaneous and quantitative detection of Listeria monocytogenes, Vibrio parahaemolyticus, and Escherichia coli O157:H7. In this work, the entire experimental process could be completed in 20 min at 37 degrees C. The limits of detection (LODs) of EuNP-based LFIA-RPA were 9.0 colony-forming units (CFU)/mL for Listeria monocytogenes, 7.0 CFU/mL for Vibrio parahaemolyticus, and 4.0 CFU/mL for Escherichia coli O157:H7. No cross-reaction could be observed in 22 bacterial strains. The fluorescent LFIA-RPA assay exhibits high sensitivity and good specificity. Moreover, the average recovery of the three food-borne pathogens spiked in food samples was 90.9-114.2%. The experiments indicate the accuracy and reliability of the multiple fluorescent test strips. Our developed EuNP-based LFIA-RPA assay is a promising analytical tool for the rapid and simultaneous detection of multiple low concentrations of food-borne pathogens

    Pilot Study on Interferon-γ-producing T Cell Subsets after the Protective Vaccination with Radiation-attenuated Cercaria of Schistosoma japonicum in the Miniature Pig Model

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    CLAWN miniature pig has been shown to serve as a suitable host for the experimental infection of Schistosoma japonicum. In this study, we found that radiation-attenuated cercaria (RAC) vaccine gave CLAWN miniature pigs protective immunity against subsequent challenge infection with S. japonicum cercaria. To characterize the protective immune response of the pig model vaccinated by attenuated cercaria, flow cytometric analysis of the reactive T cell subsets was performed. The intracellular interferon (IFN)-γ and the cell surface markers revealed the peripheral blood CD3+ T-lymphocytes produced significant amounts of IFN-γ during the immunization period and after the challenge infection. CD4+ αβ-T cells as well as CD4+/CD8αmid double positive and/or CD8αhigh αβ-T cells were the major IFN-γ-producing CD3+ T cells. On the contrary, γδ T cells did not produce intracellular IFN-γ. Our results suggested that RAC-vaccinated miniature pigs showed effective protective immunity through the activation of αβ T cells bearing antigen specific T-cell receptors but not through the activation of γδ T cells

    Design and analysis of a photon counting system using covered single photon avalanche photodiode

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    A photon counting system using covered single photon avalanche diode (SPAD) based on a standard IC process (0.18 μm) is designed and analysed in this work. The SPAD is formed using the medium voltage (MV) doping layers of the process. To reduce the dark count rate (DCR) in the SPAD, a shaded SPAD with the same structure is fabricated on the same chip which is covered by a metal layer and only providing DCR for the DCR correction. This DCR provided by the shaded SPAD can be also used for the real-time on chip monitoring of some other parameters such as temperature, breakdown voltage and afterpulsing probability. Experimental results show that the SPAD developed is able to detect the visible light from 450 nm to 850 nm with a 35 % peak photon detection probability achieved at around 550 nm with bias voltage of 16 V (excess voltage of 3 V). A timing jitter of 176 ps is measured with an excess voltage of 3 V. The dark count rate in the SPAD tested is about 1.38 cps/μm2 with excess bias voltage of 1 V and 14.62 cps/μm2 with the excess bias voltage of 3 V without the DCR correction. Results also show that a reduction of more than 85 % in the DCR (background noise) can be achieved when the DCR correction is applied resulting in a DCR of 1.68 cps/μm2 with excess bias voltage of 3 V. By monitoring the DCR of the shaded SPAD, the breakdown voltage and temperature of other on chip SPAD can be measured. The potential usefulness of the afterpulsing probability monitoring using the shaded SPAD and the crosstalk probability between SPADs on the chip are analyzed. In addition, the effects of process variations on the SPAD performance is investigated by testing 10 chips with the same SPADs fabricated and potential method is proposed for alleviating the process variations in the SPAD arrays

    Origin of a novel protein-coding gene family with similar signal sequence in Schistosoma japonicum

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    BackgroundEvolution of novel protein-coding genes is the bedrock of adaptive evolution. Recently, we identified six protein-coding genes with similar signal sequence from Schistosoma japonicum egg stage mRNA using signal sequence trap (SST). To find the mechanism underlying the origination of these genes with similar core promoter regions and signal sequence, we adopted an integrated approach utilizing whole genome, transcriptome and proteome database BLAST queries, other bioinformatics tools, and molecular analyses.ResultsOur data, in combination with database analyses showed evidences of expression of these genes both at the mRNA and protein levels exclusively in all developmental stages of S. japonicum. The signal sequence motif was identified in 27 distinct S. japonicum UniGene entries with multiple mRNA transcripts, and in 34 genome contigs distributed within 18 scaffolds with evidence of genome-wide dispersion. No homolog of these genes or similar domain was found in deposited data from any other organism. We observed preponderance of flanking repetitive elements (REs), albeit partial copies, especially of the RTE-like and Perere class at either side of the duplication source locus. The role of REs as major mediators of DNA-level recombination leading to dispersive duplication is discussed with evidence from our analyses. We also identified a stepwise pathway towards functional selection in evolving genes by alternative splicing. Equally, the possible transcription models of some protein-coding representatives of the duplicons are presented with evidence of expression in vitro.ConclusionOur findings contribute to the accumulating evidence of the role of REs in the generation of evolutionary novelties in organisms\u27 genomes

    GRIK3 rs490647 is a Common Genetic Variant between Personality and Subjective Well-being in Chinese Han Population

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    Personality and subjective well-being (SWB) have been suggested to be strongly related in previous studies. This study was intended to confirm the relationship between personality and SWB and tried to seek out the genetic variants which underlie both personality and SWB. The subjects were 890 participants from Chinese Han population. We evaluated their personality using the Big Five Inventory (BFI) and used the Satisfaction With Life Scale (SWLS) to reflect their SWB. Five single nucleotide polymorphisms (SNPs) were selected from the literature (rs1426371, rs2164273, rs322931, rs3756290, rs490647) and genotyped for genetic association study. We found negative correlations between neuroticism and SWB. On the contrary, extraversion and agreeableness were positively associated with SWB. Three SNPs (rs2164273, rs3756290, rs490647) out of the five were found to connect with personality (extraversion, neuroticism, conscientiousness and openness to experience) and rs490647 variants of GRIK3 was also associated with SWB. Individuals carrying G allele at this site were predisposed to have lower risk to be neuroticism and greater chance to be extraverted, open and satisfied with their life. In summary, our study revealed that rs490647 might be a good candidate genetic variant for personality and SWB in Chinese Han population
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