The development of genus-specific and species-specific real-time PCR assays for the authentication of Patagonian toothfish and Antarctic toothfish in commercial seafood products.

BACKGROUND: The substitution or mislabeling of toothfish is an issue of significant concern for seafood authorities; it also reduces the effectiveness of marine conservation and management programs for its over-exploitation and illegal trafficking, boosting the need for identification methods. RESULTS: Two species-specific real-time polymerase chain reaction (PCR) assays for the identification of Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni) and a genus-specific real-time PCR assay for Dissostichus spp. identification were developed based on fragments of the 16S rRNA and COI (cytochrome c oxidase subunit I) genes. These methods were confirmed to be rapid, simple, and sensitive (absolute sensitivity of 0.0002 ng µL-1 and relative sensitivity of 0.1 g kg-1 with good specificity). These methods can be applied to processed and commercial fish products. CONCLUSIONS: These approaches can be beneficial for protecting both consumers and producers from economic fraud and might also help protect toothfish from over-exploitation as well as combat illegal, unreported, and unregulated (IUU) fisheries. © 2021 Society of Chemical Industry.

Determination of the cleavage site of enterovirus 71 VP0 and the effect of this cleavage on viral infectivity and assembly.

Hand, foot, and mouth disease (HFMD) is a major public health concern, especially among infants and young children. The primary pathogen of HFMD is enterovirus 71 (EV71), whose capsid assembly mechanism including capsid protein processing has been widely studied. However, some of its mechanisms remain unclear, such as the VP0 cleavage. This study aimed to identify the cleavage site of the EV71 VP0 capsid protein and to elucidate the effects of EV71 VP0 cleavage on viral infectivity and assembly. A mass spectrometry analysis indicated that the cleavage site of EV71 VP0 is located between residues Lys69 and Ser70. To analyze the importance of either residue to cleavage, we designed single mutations of Lys69, Ser70 and double mutations respectively and implemented these genomes to encapsulation. The results indicated that Ser70 is more important for VP0 cleavage and EV71 infectivity. In addition, exogenous expression of EV71 protease 2A and 3C was used to verify whether they play roles in VP0 cleavage. Analyses also showed that none of them participate in this process. This study provides novel insights into the mechanisms of EV71 capsid maturation, which may be a potential target to improve the productivity and immunogenicity of EV71 vaccines.

Proteomic and transcriptomic analyses of saliva and salivary glands from the Asian citrus psyllid, Diaphorina citri.

Salivary secretions play critical roles in interactions among insects, insect-vectored pathogens, and host plants. The Asian citrus psyllid Diaphorina citri is a sap-sucking Hemipteran that serves as a vector for Candidatus Liberibacter asiaticus, the causal agent of citrus greening disease ("Huanglongbing" or HLB). D. citri continuously injects saliva into host plants using specialized stylets so as to feed and transmit the HLB pathogen. Knowledge on the composition and function of salivary proteins of this pest is very limited. In this study, proteomic and transcriptomic approaches were adopted to characterize the protein composition of the saliva and salivary glands in D. citri. A total of 246 and 483 proteins were identified in saliva and dissected salivary glands, respectively, via LC-MS/MS analyses. Comparative analyses of the identified proteins were performed between D. citri and other reported Hemipteran insect species. Transcription levels of the genes coding for the identified proteins were determined via RNA-sequencing among different tissues including salivary glands and other digestive tissues. Identification of putative effectors that are expressed exclusively or abundantly in salivary glands provides the foundation for future functional studies towards the understanding of their roles in interactions among D. citri, HLB pathogen, and their citrus host. BIOLOGICAL SIGNIFICANCE: This is a systematic analysis on proteins in saliva and dissected salivary glands. A high percentage of novel proteins have been identified due to the large amounts of samples collected. This report gives a more comprehensive repertoire of potential effector proteins that may be possibly involved in modulating host defense, altering nutrient metabolism, and facilitating Ca. L. asiaticus transmission.

Seadragon genome analysis provides insights into its phenotype and sex determination locus.

The iconic phenotype of seadragons includes leaf-like appendages, a toothless tubular mouth, and male pregnancy involving incubation of fertilized eggs on an open "brood patch." We de novo-sequenced male and female genomes of the common seadragon (Phyllopteryx taeniolatus) and its closely related species, the alligator pipefish (Syngnathoides biaculeatus). Transcription profiles from an evolutionary novelty, the leaf-like appendages, show that a set of genes typically involved in fin development have been co-opted as well as an enrichment of transcripts for potential tissue repair and immune defense genes. The zebrafish mutants for scpp5, which is lost in all syngnathids, were found to lack or have deformed pharyngeal teeth, supporting the hypothesis that the loss of scpp5 has contributed to the loss of teeth in syngnathids. A putative sex-determining locus encoding a male-specific amhr2y gene shared by common seadragon and alligator pipefish was identified.