Molecular characterization of eight segments of Scylla serrata reovirus (SsRV) provides the complete genome sequence.

Scylla serrata reovirus (SsRV) is one of the most prevalent viral pathogens of mud crabs (S. serrata). Of the 12 double-stranded RNA (dsRNA) genomic segments (S1-S12), the three largest (S1-S3) and S7 were sequenced previously and were shown to have no or only low sequence homology to known members within the family Reoviridae. The sequences of the remaining segments, S4-S6 and S8-S12, are reported here. With the exception of S4, all have single open reading frames (ORFs) on their positive strands, and the terminal sequences 5'-AUAAA(U)/(C) (A)/(U)…G(A)/(G) (A)/(U) (A)/(C)AAC(G)/(U)AU-3' are conserved among currently and previously sequenced segments. S4 contains two out-of-phase ORFs on the positive strand, suggesting that this segment is bicistronic. The ORFs of segments S4-S6 and S8-S12 have low or no homology to other reovirus genes, with the exception that all of the SsRV segments have high sequence similarity to those of mud crab reovirus (MCRV) and share the same 5'- and 3'-terminal nucleotide sequences, suggesting that the two viruses belong to the same species in the family Reoviridae. Analysis of virion proteins revealed that SsRV contains at least eight structural proteins, with sizes ranging from 25 to 160 kDa.

Measurement of Circulating Tumor Cells to Track Hepatocellular Carcinoma Progression After Liver Transplantation-Case Report.

Management of patients with hepatocellular carcinoma (HCC) largely relies on surgery and other systemic therapies. However, the poor diagnosis of cancer recurrence or metastasis can lead to a high frequency of treatment failure. Thus, factors that can predict disease status and prognosis of patients need to be identified. Circulating tumor cells (CTCs) are known to accurately predict survival of patients. Here, we report a case in which CTCs successfully predicted the progression of metastatic colon polyps after interventional therapy for HCC. A 48-year-old man was diagnosed with HCC with moderate differentiation in 2016 and subsequently underwent orthotopic liver transplantation. Discharge medications were continued with immunosuppressants (tacrolimus) and antiviral drugs (Titin). In 2018, a colon polyp, a type of tubular adenoma, was detected and surgically removed. However, in 2020, the same tubular adenoma recurred. During cancer progression, CTC counts were measured to monitor the status of metastasis, and a positive correlation was noted between the dynamic change in CTC counts and cancer response (metastasis or recurrence). When diagnosing the metastatic adenoma, the number of cytokeratin-positive CTCs was significantly increased; however, it dropped to zero after the polyp was surgically removed. The same change in CTC counts was observed during the second recurrence of the adenoma, and a subgroup of CTCs, cell surface vimentin-positive CTCs, was significantly increased. The CTC count dropped to an undetectable level after the surgery for the first time. In summary, we presented a clinical case in which CTC counts could predict disease progression during HCC metastasis. Thus, CTC counts should be measured after liver transplantation in patients with HCC for diagnosis and clinical decision-making as it is effective in monitoring cancer progression.

Rapid and sensitive detection of mud crab Scylla serrata reovirus by a reverse transcription loop-mediated isothermal amplification assay.

Scylla serrata reovirus (SsRV) is one of the most prevalent viral pathogens of the mud crab (S. serrata). This pathogen is widespread in east China and causes severe economic losses to the nation's mud crab industry. Early detection of this pathogen is necessary for disease control and reduction of economic loss. In the present study, a reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) assay for the rapid and sensitive detection of SsRV was developed and evaluated. The LAMP reaction mix was optimized, as were the reaction temperature (62°C) and the duration of the assay (60min). The sensitivity of the RT-LAMP assay was determined to be 0.8fg SsRV dsRNA, which was 1000-fold higher than that of a one-step reverse transcription polymerase chain reaction (RT-PCR). The RT-LAMP assay also had higher sensitivity than a one-step RT-PCR, as it identified nine more positive cases from 55 mud crabs suspected of having SsRV. No cross-reactivity was found with the DNA/RNA of other tested viruses and SsRV-negative animals. Importantly, the assay can be completed within 60min and is faster than conventional RT-PCR. In summary, the RT-LAMP assay is a simple, cost-effective, sensitive, and specific tool for the rapid detection of SsRV infection.