Application of the modified cytosine base-editing in the cultured cells of bama minipig.

Bama minipig is a unique miniature swine bred from China. Their favorable characteristics include delicious meat, strong adaptability, tolerance to rough feed, and high levels of stress tolerance. Unfavorable characteristics are their low lean meat percentage, high fat content, slow growth rate, and low feed conversion ratio. Genome-editing technology using CRISPR/Cas9 efficiently knocked out the myostatin gene (MSTN) that has a negative regulatory effect on muscle production, effectively promoting pig muscle growth and increasing lean meat percentage of the pigs. However, CRISPR/Cas9 genome editing technology is based on random mutations implemented by DNA double-strand breaks, which may trigger genomic off-target effects and chromosomal rearrangements. The application of CRISPR/Cas9 to improve economic traits in pigs has raised biosafety concerns. Base editor (BE) developed based on CRISPR/Cas9 such as cytosine base editor (CBE) effectively achieve targeted modification of a single base without relying on DNA double-strand breaks. Hence, the method has greater safety in the genetic improvement of pigs. The aim of the present study is to utilize a modified CBE to generate MSTN-knockout cells of Bama minipigs. Our results showed that the constructed "all-in-one"-modified CBE plasmid achieved directional conversion of a single C·G base pair to a T·A base pair of the MSTN target in Bama miniature pig fibroblast cells. We successfully constructed multiple single-cell colonies of Bama minipigs fibroblast cells carrying the MSTN premature termination and verified that there were no genomic off-target effects detected. This study provides a foundation for further application of somatic cell cloning to construct MSTN-edited Bama minipigs that carry only a single-base mutation and avoids biosafety risks to a large extent, thereby providing experience and a reference for the base editing of other genetic loci in Bama minipigs.

[Oxidative stress and semen parameters in the serum and seminal plasma of infertile men with chronic viral hepatitis].

OBJECTIVE: To investigate the malondialdehyde (MDA) level and paraoxonase-1 (PON-1) activity in the serum and seminal plasma of infertile men with chronic viral hepatitis and their influence on the semen parameters of the patients. METHODS: We collected serum and semen samples from 42 infertile men, 45 infertile males with chronic viral hepatitis, and 50 healthy fertile men as controls. We measured the MDA level in the serum and seminal plasma by spectrophotometry, detected the PON-1 activity by spectrophotometry, and determined the sperm DNA fragmentation index (DFI) by acridine orange fluorescence staining. RESULTS: The MDA level was significantly higher but the PON-1 activity remarkably lower in the serum and seminal plasma of the infertile males with chronic viral hepatitis than in the healthy controls and infertile patients (P <0.01 or P <0.05). Total sperm motility and sperm survival rate were significantly lower while the sperm DFI markedly higher in the former than in the latter two groups (P <0.01 or P <0.05). No statistically significant difference was found among the three groups in sperm concentration (P >0.05). The WBC counts in the semen of the infertile and infertile with chronic viral hepatitis groups were significantly higher than that in the health controls (P <0.05). The MDA level and PON-1 activity in the seminal plasma were positively correlated with those in the serum in the infertile males with chronic viral hepatitis (r=0.57 or 0.48, P <0.01). CONCLUSION: Virus-induced chronic active hepatitis enhances oxidative stress in the reproductive system, aggravates sperm damage, and affects sperm quality parameters.

[Diagnostic value of serum CEACAM1 in patients with pancreatic cancer].

OBJECTIVE: To investigate the diagnostic value of serum CEACAM1 in patients with pancreatic cancer. METHODS: Fifty patients with pancreatic cancer and 50 with chronic pancreatitis were examine for serum levels of CEACAM1 by enzyme-linked immunosorbent assay (ELISA). The cut-off values and area under curve (AUC) of CEACAM1 was obtained by receiver operating characteristic (ROC) curve. The diagnostic efficiency of the tumor markers for pancreatic cancer was assessed by the fourfold table. RESULTS: The serum level and positivity rate of CEACAM1 in pancreatic cancer patients were higher than those in chronic pancreatitis patients (P<0.05). Based on the ROC curve, the cut-off values and AUC of CEACAM1 were 13.835 ng/ml and 0.780, respectively (P<0.05). In pancreatic cancer patients, the diagnostic sensitivities of the tumor markers decreased in the order of CEACAM1 < CA242 < CA19-9 (P<0.05), and the specificity in the order of CA242 < CA19-9 < CEACAM1 (P<0.05). CONCLUSION: CEACAM1 shows a higher diagnostic sensitivity than CA19-9 and CA242 for pancreatic cancer, but due to its low specificity this marker alone is not sufficient for diagnostic purposes.

[Effects of survivin antisense RNA and HSP70 double gene transfection on MCF-7 cells in vitro].

OBJECTIVE: To explore the effects of survivin antisense RNA and HSP70 double gene transfection on breast cancer cell line MCF-7. METHODS: MCF-7 cells was transfected with the double-gene vector pIRES2-EGFP-survivin antisense RNA/HSP70 via liposome. After a 72-h transfection, the cells were collected for observation under inverted fluorescent microscope. The changes of survivin mRNA and HSP70 protein expressions in the cells were detected with real-time PCR and Western-blot before and after the cell transfection, and the apoptotic rate of the transfected MCF-7 cells was detected by flow cytometry analysis with Annexin-V-cy5/7AAD double staining. RESULTS: Green fluorescence was detected in MCF-7 cells transfected with the double-gene expression vector and the empty vector under inverted fluorescent microscope. The expression level of survivin mRNA in the cells was reduced effectively after the transfection with the double-gene expression vector, which also induced obvious cell apoptosis and enhanced the expression level of HSP70 protein as compared with those in MCF-7 cells transfected with the empty vector and the untransfected MCF-7 cells. CONCLUSION: Survivin antisense RNA can interfere with the expression of endogenous survivin and induce apoptosis of MCF-7 cells. HSP70 can increase the expression of HSP70 protein in MCF-7 cells.