Calcined oyster is a commonly used shellfish traditional Chinese medicine in clinical practice in China. During the processing of oysters, their microscopic characteristics are destroyed, and open-fire calcination can damage the DNA of oysters, making it difficult to identify the primary source. The establishment of a specific polymerase chain reaction(PCR) method for the identification of calcined oysters can provide a guarantee for the safety and clinical efficacy of the medicine and its processed products. With Ostrea gigas as an example, the DNA extraction method of decoction pieces and formula particles of calcined oysters was improved, and high-quality DNA was obtained. Based on the specific single nucleotide polymorphism(SNP) sites of O. gigas and the other two species, the specific identification primers were designed, and the site-specific identification method of formula granules of calcined oyster(O. gigas) was established. The specificity and applicability of the method were investigated. The results showed that when the annealing temperature was 54 ℃, and the cycle was 44 times, the PCR amplified products of calcined oyster(O. gigas) and its formula granules produced a single bright identification band at 102 bp, while the other two species of oysters, O. talienwhanensis Crosse and O. rivularis Gould, had no band. In this study, DNA extraction and PCR identification of animal medicinal materials by calcination were established for the first time, which provided a tool for solving the difficult identification of calcined decoction pieces and ensuring drug safety.
Animals ; Ostrea/classification* ; Polymerase Chain Reaction/methods* ; Polymorphism, Single Nucleotide ; DNA/genetics*

The N⁶-methylation of RNA adenosines (N⁶-methyladenosine, m⁶A) is an important regulator of gene expression with critical implications in vertebrate and insect development. However, the developmental significance of epitranscriptomes in lophotrochozoan organisms remains unknown. Using methylated RNA immunoprecipitation sequencing (MeRIP-seq), we generated transcriptome-wide m⁶A-RNA methylomes covering the entire development of the oyster from oocytes to juveniles. Oyster RNA classes display specific m⁶A signatures, with messenger RNAs (mRNAs) and long non-coding RNAs (lncRNAs) exhibiting distinct profiles and being highly methylated compared to transposable element (TE) transcripts. Epitranscriptomes are dynamic and correspond to the chronological steps of development (cleavage, gastrulation, organogenesis, and metamorphosis), with minimal mRNA and lncRNA methylation at the morula stage followed by a global increase. mRNA m⁶A levels are correlated with transcript levels, and shifts in methylation profiles correspond to expression kinetics. Differentially methylated transcripts cluster according to embryo-larval stages and bear the corresponding developmental functions (cell division, signal transduction, morphogenesis, and cell differentiation). The m⁶A level of TE transcripts is also regulated and peaks during the gastrulation. We demonstrate that m⁶A-RNA methylomes are dynamic and associated with gene expression regulation during oyster development. The putative epitranscriptome implication in the cleavage, maternal-to-zygotic transition, and cell differentiation in a lophotrochozoan model brings new insights into the control and evolution of developmental processes.
Animals ; RNA/metabolism* ; Methylation ; RNA, Messenger/metabolism* ; Transcriptome ; Ostreidae/metabolism* ; RNA, Long Noncoding/metabolism*

Objective: To evaluate the application of real-time RT-PCR and semi-nested RT-PCR in the detection of norovirus in oysters and analyzing the genetic characteristics of the isolates. Methods: Real-time fluorescent RT-PCR and semi-nested RT-PCR were used to detect norovirus GⅠ/GⅡ in fresh oysters collected from the markets in Beijing from November 2014 to October 2015. The detection rate of the parallel test was also analyzed. In addition, the reliability of semi-nested RT-PCR was evaluated by agreement rate and consistency test (Kappa value). The positive products of norovirus GⅠ/GⅡ capsid protein region gene by semi-nested RT-PCR were sequenced. Software BioEdit 7.0.9.0 was used for sequence alignment, and software Mega 6.0 was used to construct the evolutionary tree. Results: In 72 samples, the detection rate of norovirus was 31.94% (23/72) by real-time RT-PCR, 38.89% (28/72) by semi-nested RT-PCR and 48.61% (35/72) by parallel test. The coincidence rate of the two methods was 73.61%, a moderate degree (Kappa value =0.43). A total of 13 norovirus strains were successfully sequenced, and 11 strains (7 GⅡ.17 strains, 2 GⅡ. 4 Sydney_ 2012 strains, 1 GⅡ. 1 strain and 1 GⅡ. 21 strain) were obtained from norovirus positive samples by two RT-PCR methods, two strains (1 GⅡ. 17 strain and 1 GⅡ. 3 strain) were obtained from real-time RT-PCR negative samples which were positive for norovirus by semi-nested RT-PCR. The similarity between these strains and reference strains from diarrhea patients, environmental sewage, and shellfish products were 84.4% - 100.0%. Conclusions: The parallel test of norovirus in oysters by two RT-PCR methods can improve the detection rate and detect more genotypes. Norovirus strains in oysters were highly homologous with reference strains from diarrheal patients, environmental sewage, and shellfish products. Therefore, surveillance, prevention and control for norovirus should be carried out in people who have frequent contacts with oysters and related environments.
Animals ; Beijing ; Humans ; Norovirus/genetics* ; Ostreidae ; RNA, Viral/genetics* ; Real-Time Polymerase Chain Reaction ; Reproducibility of Results ; Reverse Transcriptase Polymerase Chain Reaction

Animals ; Cadmium/toxicity* ; Dysbiosis/metabolism* ; Gastrointestinal Microbiome ; Glutamine/pharmacology* ; Methionine ; Mice ; Mice, Inbred C57BL ; Ostreidae ; Protein Hydrolysates ; Tyrosine

Aims: Escherichia coli O157:H7 is known to be transmitted via fecal-oral route, where water plays a role in the transmission process. Oysters as bivalves, bio accumulate pathogens from the water through filter feeding and are suspected to play a role as disease transmission vector. In Malaysia, the data on oyster’s microbiological quality are limited. Hence, it was vital to conduct oyster related studies in Malaysia. The main objectives of this study include the enumeration of most probable number (MPN) of fecal coliforms and E. coli and isolation of E. coli from oyster (Crassostrea iredalei) and water sample for the detection of 16S rRNA and HlyA (Hemolysin A) genes of E. coli O157:H7. Methodology and results: A total of 120 oysters and water samples (n=6) were collected from a fisherman village located in southern Malaysia. Total fecal coliforms and E. coli were determined using the MPN procedure. Colonies of E. coli were identified based on Gram staining, biochemical test, and PCR detection for the presence of 16S rRNA and HlyA gene of E. coli O157:H7. The enumeration results showed that the MPN of the fecal coliforms and E. coli found in the collected oyster samples do not meet the standard to be directed for human consumption (0.72 ± 0.19 × 104 MPN/100 g and 0.13 ± 0.03 × 10 4 MPN/100 g, respectively). The PCR assays showed that 16 out of the 104 (15.38%) of E. coli isolated from water and oysters showed the presence of HlyA gene. The phylogenetic tree analysis showed there were genetic relationships between the HlyA gene of the E. coli isolated in this study with the ones isolated from calf and human faeces. Conclusion, significance and impact of study The detection of Shiga toxin producing E. coli O157:H7 (HlyA gene) in cage cultured oysters (C. iredalei) and water from southern Malaysia was first time reported here. In the future, more study can be conducted to study the expression of the HlyA gene and confirm of its identity as E. coli O157:H7 using different target genes such as eaeA (encodes a 94 kD outer membrane protein called intimin) and Stx1 (Shiga toxin, Shigella dysenteriae type 1).
Escherichia coli O157 ; Crassostrea

Crassostrea sikamea (C.sikamea) is an important edible and medicinal seafood in China. In the present study, a compound named flazin was separated and identified from the ethyl acetate extract of C.sikamea (EAECs) for the first time. In addition, the 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra zolium (MTS) assay revealed that EAECs and flazin inhibited the transformation of splenic lymphocytes in vitro. Moreover, flazin (20 μg·mL
Animals ; Carbolines ; Crassostrea ; Furans ; Lymphocytes ; Rats ; Rats, Sprague-Dawley ; Spleen

Defensins are endogenous cationic antimicrobial peptides rich in arginine and cysteine residues. They are important immune factors resisting pathogenic bacteria infection for mollusks. The 43 amino acid residues near the carboxyl terminal for Crassostrea gigas defensin (CgD) form its mature peptide region, responsible for the biological activity of CgD. First, two target genes, CgDH⁺ (with 6×His-tag at 3' end) and CgDH- (without 6×His-tag at 3' end) were separated and amplified by RT-PCR with specific primers from Crassostrea gigas mantle. These two target genes were ligated to the expression vector pPICZαA to construct recombinant expression vectors, pPICZαA-CgDH⁺ and pPICZαA-CgDH-, which were transformed into competent Pichia pastoris X-33 cells by electroporation respectively. The recombinant target proteins, CgDH⁺ and CgDH-, were induced for 72 h with 1% methanol at 29 °C and 250 r/min. The recombinant CgDH⁺ (5.78 kDa) was purified by immobilized metal affinity chromatography (IMAC), and identified by MALDI-TOF-TOF analysis, demonstrating that it was the expected target protein. Based on the concentration of the purified product, the estimated yield of recombinant CgDH⁺ was 2.32 mg/L. Antimicrobial assay showed that the culture medium supernatant containing recombinant CgDH⁺ and recombinant CgDH-, respectively, had activities against Staphylococcus aureus and Pseudomonas aeruginosa, indicating that the existence of 6×His tag in the recombinant proteins do not affect their biological activities.
Animals ; Anti-Bacterial Agents ; Antimicrobial Cationic Peptides ; Crassostrea ; Defensins ; Pichia ; Recombinant Proteins

Gymnophalloides seoi (Digenea: Gymnophallidae) is a human intestinal trematode contracted by eating raw oysters (Crassostrea gigas) in the Republic of Korea (=Korea). It has been known to be highly endemic in Aphae Island, Shinan-gun, Jeollanam-do (Province). However, recent epidemiological status of G. seoi has not been reported since the 1990s. In this study, we investigated the prevalence of G. seoi metacercariae in natural and cultured oysters collected from 3 islands and 2 coastal areas in western parts of Korea. The oysters were examined using the artificial digestion method followed by stereomicroscopy. The overall positive rate of G. seoi metacercariae in natural oysters was 66.0% (99/150), and the oysters collected from Yubu Island showed the highest infection rate (74.0%). However, the metacercarial density per oyster was relatively low (1.5–2.4 per oyster). By contrast, no metacercaria was found in cultured oysters purchased from 2 coastal areas in Chungcheongnam-do. Thus, we could confirm that natural oysters produced from 3 western coastal islands are infected with G. seoi metacercariae, whereas cultured oysters purchased from 2 coastal areas were free from infection.
Chungcheongnam-do ; Digestion ; Eating ; Humans ; Islands ; Jeollanam-do ; Korea ; Metacercariae ; Methods ; Ostreidae ; Prevalence ; Republic of Korea

In patients with hepatocellular carcinoma (HCC) or liver cirrhosis (LC) accompanied by hepatitis E virus (HEV) infection, hepatic failure often leads to debility. Here, we report about a 63-year-old man with alcoholic LC who was referred to our hospital with jaundice and abdominal distension 10 days earlier. Abdominal computed tomography showed necrotic HCC accompanied by left lobe shrinkage without tumor progression. Laboratory and imaging findings revealed no acute infection focus. The patient reported no herbal medicine or alcohol consumption, and there was no evidence of acute viral hepatitis. One month later, HEV immunoglobulin M positivity was confirmed, and deterioration of liver function due to HEV infection was suspected. The patient often ate raw oysters and sashimi, as well as boar meat, which is a well-known risk food for HEV infection. His umbilical hernia deteriorated due to tense ascites and infection by skin abrasion. The patient progressed to hepatorenal syndrome and eventually died. Liver function preservation is important when treating HCC patients. Therefore, clinicians should pay more attention to the prevention of HEV and others causes of direct liver injury.
Alcohol Drinking ; Alcoholics ; Ascites ; Carcinoma, Hepatocellular ; Hepatitis E virus ; Hepatitis E ; Hepatitis ; Hepatorenal Syndrome ; Herbal Medicine ; Hernia, Umbilical ; Humans ; Immunoglobulin M ; Jaundice ; Liver ; Liver Cirrhosis ; Liver Failure ; Meat ; Middle Aged ; Ostreidae ; Skin ; Transcutaneous Electric Nerve Stimulation

This study examined the microbiological quality of daycare center meals. Six menu items from five daycare centers in Daegu included uncooked processed foods (seasoned cucumber and lettuce salad), post-preparation after cooking processed foods (rolled omelet and seasoned soybean sprout), and cooking processed foods (panbroiled beef with oyster sauce and seasoned pork roast). Microbiological analyses were performed for the aerobic plate counts (APC), coliforms, and Escherichia coli. The analyses were conducted in July and November 2017. The mean APC and coliform count of seasoned cucumber decreased significantly from 4.71 log colony forming units (CFU)/g and 2.50 log CFU/g in July to 4.07 log CFU/g and 1.78 log CFU/g in November, respectively (P < 0.01 and P < 0.001). The APC of panbroiled beef with oyster sauce and seasoned pork roast were significantly lower in July (1.84 and 1.79 log CFU/g) than in November (2.41 and 2.28 log CFU/g) (P < 0.001). The coliform counts of panbroiled beef with oyster sauce and seasoned pork roast were significantly greater in November (2.11 and 1.62 log CFU/g) (P < 0.001). E. coli was not detected. Among the foods prepared using the three preparation processes, the post-preparation after cooking processed foods had the lowest microbial quality. The APC and coliform counts of cooking processed foods were satisfactory in July, with an acceptable rating for pan-broiled beef with oyster sauce in November. Time-temperature control and the prevention of cross-contamination are essential during meal production for food safety, regardless of the season.
Cooking ; Daegu ; Escherichia coli ; Food Safety ; Lettuce ; Meals ; Ostreidae ; Red Meat ; Seasons ; Soybeans ; Stem Cells