ABSTRACT
Objective To establish a loop-mediated isothermal amplification method for detection of Campylobacter jejuni.Methods Six sets of primers were designed to recognize Campylobacter jejuni specific gene hipO.One was selected as the optimal primer and its specificity and sensitivity to Campylobacter jejuni were evaluated by LAMP reaction in 60 minutes at 62℃.Results The results recorded by the turbidity meter showed that the sensitivity of LAMP with a detection limit of 6.97×102 copies/μl was ten times that of PCR.Conclusion LAMP is a potential and valuable method of detection of Campylobacter jejuni due to its rapidity,simplicity,low cost and accuracy.It is especially suitable for grass-roots medical units.
ABSTRACT
Objective To find simple and effective methods of preservation for Achromobacter xylosoxidans bacteriophages.Methods The plaque forming unit( PFU) of surviving phages under different preservation conditions and temperatures at different time points was determined.Results and Conclusion The titers of phiAxp-1 and phiAxp-2 main-tained at the initial 1010 PFU/ml, and that of phiAxp-3 decreased slightly from 1011 PFU/ml to 1010 PFU/ml 16 months after the three Achromobacter xylosoxidans bacteriophages were stored in glycerol and dimethyl sulfoxide at -80℃, -20℃and 4℃.When stored in chloroform at 4℃for 16 months, the titers of all the three phages decreased slightly but were higher than at other temperatures (-80℃, -20℃, room temperature, and 37℃) .Thus these methods can effectively preserve Achromobacter xylosoxidans bacteriophages.
ABSTRACT
Objective To demonstrate that enolase and Tuf are direct adhesions of Bifidobacterium longum( B.longum) NCC2705.Methods B.lougum NCC2705 was co-cultured with Caco-2.The change of adhesion was tested by microscopy after the purified proteins(GST-Eno and GST-Tuf) were added into the co-culture, and then statistical analysis was conduc-ted.Caco-2 cells were incubated with B.lougum NCC2705 and pathogenic bacteria (Shigella flexneri 2a or Salmonella). The level ofcytokine LDH and TNF-αfor supernatant was tested after the purified proteins ( GST-Eno and GST-Tuf) were added.Results The number of bacteria adherent to Caco-2 was reduced significantly ( P <0.05 ) after the purified proteins ( GST-Eno/GST-Tuf) were added .While Caco-2 was co-cultured with pathogens , the level of LDH and TNF-αwas significantly increased (P<0.05).When Caco-2 was incubated with B.lougum NCC2705 and pathogenic bacteria , the level of LDH and TNF-αwas significantly reduced (P<0.05), but the level of LDH and TNF-αincreased once more (P<0.05) after the purified protein (GST-Eno/GST-Tuf) was added.Conclusion B.longum NCC2705 can competitive-ly inhibit production of pathogenic bacteria in intestinal epithelial cell adhesion , while the enolization enzyme and Tuf proteins can competitively inhibit long bifidobacteria in intestinal epithelial cell adhesion effect .They are adhesion factors of bifidobacteria .