Objective:To construct Streptococcus suis type 2 Δ0948 complementary strain and verify its effect on suilysin (SLY) secretion and virulence. Methods:The SSU05_0948 gene sequence with promoter was amplified by PCR and ligated to pAT18 vector to construct complementary strain and verify its expression through Western blot. Growth curve was drawn to compare the growth of complementary strain against the wild-type strain and mutant strain in different periods. CD1 mice challenge model was used to verify whether complementary strain could restore the virulence of mutant. SLY hemolytic activity and Western blot were compared the effect of complementary strain and wild-type strain and mutant strain on SLY protein secretion at different time points.Results:The complementary strain was successfully constructed, but the expression of SSU05_0948 was lower than the wild-type strain. The growth rate of the complementary strain was significantly slower than the wild-type strain and mutant strain in the logarithmic growth phase, but the same in the platform phase. The CD1 mice challenge model showed the complementary strain could basically restore the virulence of the mutant strain. The hemolytic activity of SLY and Western blot showed that SSU05_0948 could inhibit the secretion of SLY protein in the early and middle logarithmic phase, but did not affect the secretion of SLY in the late logarithmic and platform phase, while the complementary strain could restore the secretion of SLY protein.Conclusions:The complementary strain CΔ0948 of Streptococcus suis can restore the virulence of mutant strain Δ0948, and SSU05_0948 affects the virulence of Δ0948, which provides a new idea for the prevention and treatment of Streptococcus suis.

Objective To investigate the abnormal expression of microRNA (miRNA)-25 in the serum of gastric cancer patients and its clinical significance. Methods In Xijing Hospital of Digestive Diseases,Fourth Military Medical University,86 gastric cancer patients with operation and completed follow-up data,70 gastric adenoma patients and 80 healthy controls were selected as study objects.Total RNA was isolated from the serum. After the stable and sensitive miRNA-25 absolute quantity detection method established,the serum levels of miRNA-25 in gastric carcinoma patients,gastric adenoma patients and healthy controls were tested according to this method. The expression differences of miRNA-25 in the serum of patients with gastric cancer and gastric adenoma and healthy controls were analyzed with statistic analysis,and the correlation between miRNA-25 expression level and clinic pathological features of gastric cancer was also analyzed. Results The expression level of miRNA-25 in the serum of gastric cancer patients (135. 6 fmol/μg total RNA) was significantly higher than that of gastric adenoma patients (67. 7 fmol/μg total RNA) and healthy controls (62. 2 fmol/μg total RNA)(P＜0. 01). The receiver operating characterisstic curve of miRNA-25 indicated that serum miRNA-25 with good specificity and sensitivity in gastric cancer diagnosis (AUC=0. 827). The serum level of miRNA-25 in gastric cancer patients with lymph node metastasis [(148. 3±10. 2) fmol/μg total RNA] or clinicopathological stage Ⅲ /Ⅳ patients [(146. 7±9.5) fmol/μg total RNA] was significantly higher than that of gastric cancer patients without lymph node metastasis [(120. 3±10. 1)fmol/μg total RNA] or clinicopathological stage Ⅰ/Ⅱpatients [(119. 4±12. 2) fmol/μg total RNA] (P＜0.05). The correlation statistical analysis result indicated that there was no significant difference in survival period between serum miRNA-25 highly expressed and lowly expressed gastric cancer patients (P＞0. 05).Conclusion Serum miRNA-25 testing maybe helpful in diagnosis and prognosis of gastric cancer.

Objective To investigate the effect of comprehensive nursing intervention on pregnancy outcome in patients with artificial insemination by husband. Methods 80 patients with artificial insemination by husband in the Department of Reproductive Medicine of Yichun People's Hospital from July 2016 to July 2018 were collected and divided into two groups by random number table method. The control group was treated with routine care intervention. The observation group was treated with comprehensive nursing intervention. The serum FSH level, serum estradiol concentration, serum LH level, endometrial thickness on the day of transplantation, pregnancy outcome, and psychological status in patients were observed. Results The serum LH level in the observation group was significantly higher than that in the control group (P<0.05). There was no significant difference in serum FSH level, serum estradiol concentration, endometrial thickness on the day of transplantation between the observation group and the control group (P>0.05). There was no significant difference in the clinical pregnancy rate and spontaneous abortion rate between the two groups (P>0.05). The SAS and SDS scores were lower in the observation group after the intervention, and the difference was significant from those of the control group (P<0.05). Conclusion Comprehensive nursing intervention had no significant effect on the pregnancy outcome of patients with artificial insemination by husband. The clinical pregnancy rate and spontaneous abortion rate are similar. But comprehensive nursing intervention can improve the serum LH level and improve the psychological status of patients.

Objective To determine whether coagulase-negative non-epidermal staphylococcus is methicillin-resistant coagulase-negative staphylococcus by mecA gene test,when the minimal inhibitory concentration(MIC)of oxacillin is between 0.5-2.0 mg/L.Methods The mecA gene was detected and analyzed by the cefoxitin disk diffusion,E-test,VITEK-2 Compact and polymerase chain reaction (PCR)purification.Results A total of 300 strains of coagulase-negative staphylococci were screened from 4032 patients(7.4％),of which 45 strains of Staphylococcus saprophyticus and 80 strains of Staphylococcus hemolyticus were identified by Compact VITEK-2.There was a statistically significant difference in the positive rate of mecA gene detection between Staphylococcus saprophyticus and Staphylococcus hemolyticus(P ＜0.05).The results of detection of cefoxitin disk diffusion(inhibitory zone diameter ≥ 25 mm),E-test(MIC of oxacillin between 0.5-2.0 mg/L)and Compact VITEK-2 (MIC of oxacillin between 0.5-2.0 mg/L)showed that there were 81 strains of coagulase-negative non-Staphylococci,of which 10 strains with positive mecA gene were confirmed by PCR.Conclusions When the minimal inhibitory concentration (MIC)of oxacillin against coagulase-negative non-Staphylococci stains is between 0.5-2.0 mg/L,the guidelines of the American clinical laboratory standardization institute(CLSI)should be strictly implemented in clinical microbiology laboratory and the mecA gene must be tested.Based on the wide dissemination of the mecA gene in Staphylococcus aureus population,if the mecA gene test is negative,it is reported as methicillin-susceptible coagulase-negative Staphylococcus(MSCNS),and the reverse result is reported as methicillin-resistant coagulase-negative staphylococcus(MRCNS).

Objective:To construct four retroviral plasmids for differential expression of green fluorescent protein (GFP) based on different terminal sequences of internal ribosome entry site (IRES) and provide reference for subsequent flow analysis or imaging.Methods:Based on the fact that the transcription efficiency of encephalomyocarditis virus IRES depends on its terminal sequence, IRES and enhanced GFP (EGFP) were fused into four fragments with different connection modes by overlapping PCR, and then cloned into retroviral plasmid pMSCV-NGFR. NGFR fragment was amplified by PCR and inserted in front of the retroviral plasmids pMSCV-IRES(1-4)-EGFP. These retrovirus plasmids pMSCV-NGFR-IRES(1-4)-EGFP were transfected into 293T cells. The expression ratio and mean fluorescence intensity (MFI) of EGFP were analyzed, and the expression of NGFR was also detected.Results:Four retroviral plasmids pMSCV-NGFR-IRES(1-4)-EGFP were successfully constructed. No significant difference in the expression efficiency of EGFP at 24 or 48 h was observed in 293T cells transfected with the four different retroviral plasmids, but there was significant difference in fluorescence intensity. Moreover, the expression of NGFR was not significantly different, indicating that the addition of different nucleotide sequences between IRES and EGFP would make a significant difference in the fluorescence intensity of EGFP.Conclusions:The expression intensity of EGFP was affected by the sequence between IRES and EGFP. Retroviral plasmids expressing EGFP of different intensity could meet different experimental requirements.