Objective:In order to develop an oral live vaccine vector of swine that can stably carry exogenous genes.Methods:Mutant ΔcrpΔcyaΔasdC78-1 was constructed by the method of suicide plasmid pREasd-mediated bacteria homologous recombination on the basis of attenuated Salmonella choleraesuisΔcrpΔcyaC78-1.Complementary plasmid pYA3493 with asd was electrotransformed into the mutant,and thenΔcrpΔcyaΔasdC78-1(pYA3493) host-vector balanced lethal system was constructed.Its biological characteristics were analyzed further.Results:The results of PCR and sequencing showed thatΔcrpΔcyaΔasdC78-1(pYA3493) was constructed suc-cessfully.Biological characteristics showed that the serotype of ΔcrpΔcyaΔasdC78-1(pYA3493) was identical to ΔcyaΔasdC78-1 and vaccine strain C500 and it can stably carry theΔasd gene in vitro;its growth speed was a little slower than ΔcrpΔcyaC78-1 strain,but both of their growth speeds were significantly slower than vaccine strain C500;the biochemical characteristics of ΔcrpΔcyaΔasdC78-1 ( pYA3493 ) were basically the same with ΔcrpΔcyaC78-1 strain.Oral virulence test in mice showed that the virulence ofΔcrpΔcyaΔasdC78-1 ( pYA3493 ) was similar with ΔcrpΔcyaC78-1, but its median lethal dose is 412 times of vaccine strain C500.Conclusion:These results demonstrated that attenuated Salmonella choleraesuisΔcrpΔcyaΔasdC78-1(pYA3493) strain had the potential to be used as an oral live vaccine vector for expressing foreign genes efficiently.

Objective:To investigate the effect of early gradual diet on reducing delirium in elderly patients with hip arthroplasty.Methods:From January 2018 to January 2020, 74 cases of hip arthroplasty patients aged over 65 years old who were treated in the Third Affiliated Hospital of Sun Yat-sen University were selected as the observation objects. They were randomly divided into experimental group and control group with 37 cases in each group. The experimental group was given early gradual diet on the basis of routine postoperative care, while the control group was given routine postoperative diet on the basis of routine postoperative care. The incidence of postoperative delirium, Pittsburgh Sleep Quality Index (PSQI), patient satisfaction rate, average hospitalization days and average hospitalization expenses were used to evaluate the effect of early gradual diet on reducing delirium in elderly patients with hip arthroplasty.Results:The incidence of delirium in the experimental group was 2.70% (1/37) and 16.22% (6/37) in the control group, the difference was statistically significant ( χ2 value was 3.945, P<0.05); the hospitalization days of the experimental group were (10.68±5.13) d, (13.62±7.19) d in the control group. The difference of hospitalization days was statistically significant ( t value was 2.877, P<0.01). The incidence of difficulty in falling asleep and the satisfaction rate of the experimental group were 8.11% (3/37) and 94.59% (35/37) respectively, and those in the control group were 29.73% (11/37) and 78.38% (29/37) respectively, and the differences were statistically significant ( χ2 value was 5.638, 4.163, P<0.05). Conclusions:Early gradual diet after operation can reduce the incidence of delirium in elderly patients with hip arthroplasty, shorten the average hospitalization days, reduce the incidence of difficulty in falling asleep, improve patients' satisfaction, and help patients to pass through the perioperative period more safely and comfortably.

In order to develop a recombinant attenuated Salmonella typhimurium as oral live vaccine vector, we constructed recombinant plasmid pYA-sopENt100 by replacing the trc promoter with the sopE promoter and secretion signal sequence sopENt100 of Salmonella typhimurium on the basis of plasmid pYA3493. Then, the complementary plasmid pYA-sopENt100 was transformed into ΔcrpΔasdSL1344 by electroporation to generate attenuated Salmonella typhimurium type III secretion system ΔcrpΔasdSL1344 (pYA-sopENt100). We further characterized ΔcrpΔasdSL1344 (pYA-sopENt100). We also constructed a recombinant strain ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) that harbored the reporter gene-enhanced green fluorescent protein (egfp) gene. Vero cells were infected with ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) and the ability of delivery foreign antigens was tested via Western blotting analysis. The results of PCR, enzyme digestion and sequencing showed that the ΔcrpΔasdSL1344 (pYA-sopENt100) type III secretion system was constructed successfully. The serotype of ΔcrpΔasdSL1344 (pYA-sopENt100) was identical to ΔcrpΔasdSL1344 and SL1344. Compared with wild strain SL1344, the biochemical characteristics of ΔcrpΔasdSL1344 (pYA-sopENt100) had obvious change, but it was basically the same with ΔcrpΔasdSL1344. The growth speed was much slower than that of the wild strain SL1344. The chicken virulence test (LD₅₀) showed that the virulence of ΔcrpΔasdSL1344 (pYA-sopENt100) was 7×10⁴ times lower than SL1344. In addition, we observed the 37 kDa SopENt100-egfp protein in the cultured supernatant of ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) strain by Western blotting analysis. However, both the 37 kDa SopENt100-egfp protein and 27 kDa EGFP protein were detected in ΔcrpΔasdSL1344 (pYA-sopENt100-egfp)-infected Vero cells. These results demonstrated that the recombinant Salmonella typhimurium type III secretion system ΔcrpΔasdSL1344 (pYA-sopENt100) was successfully constructed, and it should be used as a live vaccine vector for expressing foreign genes.
Animals ; Bacterial Proteins ; genetics ; Cercopithecus aethiops ; Mice ; Plasmids ; Promoter Regions, Genetic ; Salmonella typhimurium ; genetics ; Type III Secretion Systems ; genetics ; Vaccines, Attenuated ; genetics ; Vero Cells ; Virulence