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Background@#Listeria monocytogenes is a gram-positive bacterium that causes listeriosis mainly in immunocompromised hosts. It can also cause foodborne outbreaks and has the ability to adapt to various environments. Peptide uptake in gram-positive bacteria is enabled by oligopeptide permeases (Opp) in a process that depends on ATP hydrolysis by OppD and F.Previously a putative protein Lmo2193 was predicted to be OppD, but little is known about the role of OppD in major processes of L. monocytogenes, such as growth, virulence, and biofilm formation. @*Objectives@#To determine whether the virulence traits of L. monocytogenes are related to OppD. @*Methods@#In this study, Lmo2193 gene deletion and complementation strains of L. monocytogenes were generated and compared with a wild-type strain for the following: adhesiveness, invasion ability, intracellular survival, proliferation, 50% lethal dose (LD50) to mice, and the amount bacteria in the mouse liver, spleen, and brain. @*Results@#The results showed that virulence of the deletion strain was 1.34 and 0.5 orders of magnitude higher than that of the wild-type and complementation strains, respectively.The function of Lmo2193 was predicted and verified as OppD from the ATPase superfamily.Deletion of lmo2193 affected the normal growth of L. monocytogenes, reduced its virulence in cells and mice, and affected its ability to form biofilms. @*Conclusions@#Deletion of the oligopeptide transporter Lmo2193 decreases the virulence of L. monocytogenes. These effects may be related to OppD's function, which provides a new perspective on the regulation of oligopeptide transporters in L. monocytogenes.
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Objective To investigate the value of muhi-detector CT (MDCT) low tension dynamic enhanced scanning on the preoperative assessment of advanced gastric cancer.Methods MDCT low tension dynamic enhanced scanning,tumor diagnosis and staging and prediction of surgery operation were performed on 43 cases of advanced gastric cancer.And the above results were compared with pathology results.Results The 36 cases were treated with resection,while 7 cases were treated by gastrointestinal anastomosis.The MDCT had 76.7 ％ (33/43) of accuracy for the preoperative T staging and 74.4 ％ (32/43) of accuracy for the preoperative N staging,respectively.The stomach wall thickness was closely related to serosal invasion (x2 =20.170 9,P ＜ 0.001).Conclusions The MDCT low tension dynamic enhanced scanning can improve the comprehensiveness and accuracy of preoperative staging of T and N in advanced gastric cancer.It is valuable for the preoperative diagnosis and treatment of gastric cancer.
