Small RNAs(sRNAs) play a significant role in the regulation of bacterial growth.When sensing certain environmental cues such as fluctuation of nutrient concentration, temperature, pH, and osmolarity, sRNAs can influence the expression of target genes.The formation of biofilms is initiated by bacteria transitioning from the planktonic to the surface-associated mode of growth, which is a self-produced extracellular matrix composed of proteins, polysaccharides, and DNA.Recent evidences have shown that small RNA plays an important role in the regulation of bacterial biofilm formation.sRNAs have key roles in biofilm formation process by base pairing with target mRNAs or interaction with modulating proteins.This review discussed the regulation mechanism and pathway of sRNAs in bacterial biofilms formation, and summarized three classical regulatory models of sRNAs in bacterial biofilms formation, this review also gives the research status and development direction of sRNAs in bacterial biofilms formation.

Objective To investigate the quinolone resistance determinants in ciprofloxacin-resistant Acinetobacter bau-mannii (ABA)clinical isolates.Methods One hundred and fourteen ciprofloxacin-resistant ABA strains were collected from six Chinese hospitals .The quinolone resistance determining region ( QRDR) of 4 target genes ( gyrA, gyrB, parC and parE) was amplified , sequenced and compared with the reference genome of ATCC 17978 to identify possible resistance-related mutations.Nine plasmid-mediated quinolone resistance (PMQR) genes (qnrA, qnrB, qnrC, qnrD, qnrS, qepA, aac(6′)-Ⅰb-cr, oqxA and oqxB) were also amplified, and the amplicons were then sequenced to determine their character-istics.Results Almost all isolates (113/114, 99.1%) harbored a substitution in codon 83 of gyrA gene, leading to a Ser83Leu mutation.Meanwhile,58.8%(67/114) of the isolates possessed dual mutations of GyrA-Ser83Leu and GyrA-Ser80Leu, which were known determinants for ciprofloxacin resistance .There were also multiple non-synonymous substitu-tions in gyrB, leading to Arg393Ser, Arg393Cys, Thr401Ala, Pro406Ser, Val430Phe, Cys440Ser and Gly480Arg muta-tions with prevalence rates of 95.6%, 0.9%, 96.5%, 96.5%, 100%, 96.5%and 96.5%,respectively.For parE, all the seven mutations were synonymous and found in more than 96%of the tested isolates.For PMQR genes, although 83.3%(95/114) of the isolates were positive for aac(6′)-Ⅰb, nocrmutations were identified.None of the other eight PMDR genes were found in our strain collection .Conclusion Although multiple mutations are identified in gyrB and parE, these mutations might be the characteristic SNP markers for specific clones , unlikely linked to quinolone resistance .No PMQR is found in the tested isolates.Mutations in chromosomal QRDR (GyrA-Ser83Leu and ParC-Ser80Leu) are the main determi-nants of ciprofloxacin resistance in our ABA collection .

Objective To compare of the difference about ectopic activation between autogenous bone graft and allograft from large segment tibia of rabbits.Methods Eighty healthy adult Chinese rabbits (6 months of age),weighing (2.5 ±-0.5)kg,were randomly divided into experimental group (allogeneic bone group) and the control group (autograft group),40 rabbits in each group.Another 10 rabbits were allogeneic bone donor.In experimental group,when 1.5 cm long rabbit tibial allograft were finishied,they were implanted into spatium intermusculare between the musculus rectus femoris and medial vastus muscle of the rabbit around the saphenous artery and were fastened to the femur by 1.0 mm Kirschner-wire.In control group,autologous tibias were done,the same as experimental group including length and position and method.Four weeks and 8 weeks and 12 weeks postoperative,respectively,the postmortem specimens were examined gross and immunohistochemistry and the expression of BMP-2 and collagen type Ⅰ of transplanted bone tissue were detected.Results BMP-2 mainly exist in cytoplasm of osteoblasts and chondrocytes undifferentiated mesenchymal cells.Collagen type Ⅰ primarily exist in the bone matrix around the pit of bone.The expression level of BMP-2 of experimental group in postoperative 4,8,12 and 16 weeks were 85.25 ± 4.47,109.44 ± 14.69,141.85 ± 9.45,116.25 ± 14.18,respectively,and the expression level of BMP-2 of control group were 103.78 ±-6.59,124.95 ± 14.94,145.46 ± 8.10,112.48 ± 13.27,respectively.The expression level of collagen type Ⅰ of experimental group in postoperative 4,8,12 and 16 weeks were 78.74 ± 7.99,95.95 ± 6.99,139.91 ± 4.32,137.76 ± 3.48,respectively,and the expression level of BMP-2 of control group were 88.87 ± 11.26,102.45 ± 2.82,140.76 ± 4.62,139.05 ± 4.55.Compared with control group,there was a significant difference in the expression level of the BMP-2 and collagen type Ⅰ of experimental group in postoperative 4,8 weeks (P ＜ 0.05),but,there was no significant difference in the expression level of the BMP-2 and collagen type Ⅰ of experimental group in postoperative 12,16 weeks (P ＞ 0.05).The amount increased gradually during 4 weeks,8 weeks,12weeks,peaked at 12 weeks,BMP-2 displayed a downward trend at 16 weeks,and collagen type Ⅰ basiclly maintain the level of 12 weeks.Conclusion Allograft segment could complete activation while they are implanted into spatium intermusculare containing famous blood supply within 3 months,there is no significant difference between autologous bone and allograft,it shows the feasibility of ectopic activation about allograft segment.

Objective To observe the damage degree and expression pattern of Caveolin-3 mRNA by ischemia-reperfusion injury in rabbits of skeletal muscle cell at different phases.Methods In this study,from April 2013 to December 2013,30 lower limbs of 15 Chinese White Rabbits were used and divided into two groups:all the left lower limbs were experimental group,which were made as an experimental model of ischemia-reperfusion injury by occluding left common iliac artery using noninvasive vascular.All the right lower limbs without surgical treatment were the control group.Gastrocnemius samples were obtained at 4h and 8h after reperfusion and handled by HE staining and observed by optical microscopy.By Real-time PCR,Caveolin-3/GAPDH mRNA were detected.Results HE stain showed:in control group,there was no edema,degeneration and inflammatory cell infiltration; in experi-meatal group,muscle cell degeneration had occured at ischemic 5 h.The edema was aggravated,a large number vacuole were formed and inflammatory cell were infiltrated at 4 h reperfusion.Reperfusion injury at 8h significantly reduced compared to 4 h.The Caveolin-3/GAPDH mRNA expression levels by SPSS 19.0 showed:Control group:1.026 ± 0.065,1.004 ±0.037,1.022 ±0.051,experimental group:1.159 ±0.073,1.445 ±0.053,1.208 ±0.058 at ischemic 5 h,4 h and 8 h reperfusion,respectively.On-line analysis of variance cases of ischemic 5 h and 4 h reperfusion and 8 h reperfusion,the experimental group than the control group were increased,with statistical significance (P ＜ 0.05).The experimental group of ischemic 5 h and 8 h reperfusion was no significant difference (P ＞ 0.05).It showed Caveolin-3 mRNA expression levels in ischemia-reperfusion 8 h group returned to normal.There was significant statistical difference between the ischemic 5 h and 4 h reperfusion (P ＜ 0.05).There was significant statistical difference between the 4 h reperfusion and 8 h reperfusion (P ＜ 0.05).Conclusion The expression of Caveolin-3 in experimental group showed a trend of first increased and then decreased.The expression levels of Caveolin-3 mRNA in skeletal muscle cells after ischemia-reperfusion injury is consistent with the development and progression of muscle cell damage.The results indicate that Caveolin-3 may play a control role in the injury and recovery of skeletal muscle cell.

Objective To develop an up-converting phosphor technology-based lateral-flow ( UPT-LF) assay for rapid detection of Listeria monocytogenes, named LM -UPT-LF.Methods Monoclonal antibodies against p 60, which was the specific virulence factor of L.monocytogenes,were prepared and covalently conjugated with up-converting phosphor nanopar-ticles (UCP-NPs) as bio-label.Then, LM-UPT-LF was established with double-antibody sandwich mode-based LF assay. Detection performance , including sensitivity and specificity , was evaluated .Results The samples with absolute contamina-ted amount of L.monocytogenes cells <10, 10-99, and 100-1000 cfu could be significantly detected as positive after in-cubation at 20 h, 18 h, and 16 h, respectively.Other 13 kinds of food-borne pathogens with concentration of 109 cfu/ml did not caused any non-specific reaction .Conclusion The established LM-UPT-LF assay could detect L.monocytogenes with high sensitivity , specificity and simplicity and provides an alternative method for food safety control .

Objective To identify critical genes in evolution of Staphylococcus aureus (S.aureus).Methods A total of 2457 genes from two whole genomes of S.aureus strains were amplified for fabricating whole genome microarray,which was employed for comparative genome hybridization (CGH) analysis of 23 strains of divergent MRSA clones,including ST239-spa t037 and ST239-spa t030.Representatives of differential genes were confirmed by PCR.Results Four gene clusters were identified to be associated with evolution of major epidemic MRSA clones.The four gene clusters were specific to ST239-spa t030,and belonged to three known genomic islands (vSa4,prophage ΦSa1 and ΦSa3).Eight genes were variable expressed in ST239-spa t030 MRSA from different coutries.Conclusion The acquisition of genomic islands vSa4,prophage ΦSa1 and ΦSa3 enhanced the virulence and resistance of ST239-spa t030 MRSA,and contributed to its rapid replacement of ST239-spa t037 MRSA in China.

Objective To explore the effect and safety of the operationive treatment of calculus incarceration in neck of gallbladder.Methods We analyzed retrospectively the clinical data of 26 cases with calculus in carceration In neck of Gallbladder.Results All 26 cases patients were found to have serious cholecystitis and unclear anatomic site in Calot's trangle.Six patients'operative way had to transform from laparoscopiccholecystectomy to cholecystectomy.Endogenous membrane of gallbladder were excised retrogradely in the operation.In operative process,there were no injury in extrahepatic bile duct,intestinal canal and vascular.The all patients were recovery and discharge after operation.Conclusion It is one kind of good choice to open the gallbladder,aspirate the bile and extract the stones.And then performing endogenous membrane retrograde cholecystectomy.For treatment of the Calot's trangle areas,blunt dissection may used.It is dangerous that using sharp dissection and electrosurgical knife.

Objective To develop an up-converting phosphor technology based lateral flow (UPT-LF) assay for rapid detection of Salmonella paratyphi A, S.paratyphi B, Escherichia coli O157 ∶H7 and Vibrio parahaemolyticus. Methods With up-converting phosphor nano-particles ( UCP-NPs ) as the bio-marker, four double-antibody-sandwich mode based UPT-LF strips for detecting the above mentioned four pathogens were prepared respectively and their sensitivi-ty, accuracy, linearity and specificity were evaluated .Furthermore, the feasibility of detecting bacteria in food samples was evaluated by different food samples artificially contaminated with less than 10 CFU target pathogens .Results The sensitivi-ty of UPT-LF assays for four pathogens was 105 ~106 CFU/ml with excellent specificity .The four strips had a good linear response with the linear fitting coefficient of determination (r) for each target pathogen ranging from 0.985 to 0.996.The positive rate of detecting pathogens from samples was acceptable .Conclusion The four developed UPT-LF strips provide a new choice for rapid , specific and sensitive and quantitative detection of S.paratyphi A , S.paratyphi B, E.coli O157∶H7 and V.parahemolyticus.

OBJECTIVETo evaluate the etiology of Shiga like toxin producing Escherichia coli (SLTEC) in children with diarrhea.

METHODSWe designed and synthesized 3 pairs of primers located in the SLT1, SLT2, and eaeA genes of enterohaemorrhagic Escherichia coli (EHEC), while the virulent genes SLT1, SLT2, and eaeA from E.coli species were amplified by polymerase chain reaction (PCR).

RESULTSOne strain of EHEC with SLT1, SLT2, and eaeA in 29 reference strains of diarrhea-causing E.coli (DCEC) and 10 strains of other enterobacteria detected by PCR had positive reactions, while all other DCEC and enterobacteria were negative. Of 474 strains of E. coli isolated from 1032 children with diarrhea and detected by PCR, 20 strains of SLT1 producing E. coli (4.2%) positive, and 7 strains of SLT2 producing E. coli (1.5%) positive; while of 74 strains of entero-SLTs-producing and invasive Escherichia coli (ESIEC), 15 strains of SLT1 (20.3%) and 5 strains of SLT2 (6.8%) were positive.

CONCLUSIONShiga-like toxin E. coli has been identified as a major etiologic agent of children with diarrhea in Taiyuan, China.

Child ; Diarrhea ; microbiology ; Escherichia coli ; classification ; isolation & purification ; pathogenicity ; Feces ; microbiology ; Humans ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity ; Shiga Toxins ; genetics

Objective To purify native F1 antigen from E pestis EV76 strain and determine its ef-ficacy against Y. pestis. Methods A new purification method was developed by the substitution of physical disruption ( glass beads) for organic solvent ( acetone and toluene) one, followed by a combination of ammo-nium sulfate fractionation and SephacrylS-200HR column filtration chromatography. Groups of mice were im-munized with F1 antigen adsorbed to 25% aluminum hydroxide in PBS by intramuscular route. The immu-nized animals were challenged subeutaneously(s, c. ) with 104 CFU of Y. pestis strain 141 at 18 weeks after the primary immunization. Results There was no IgG titre difference between two groups of mice with one-dose immunization, whereas in the two-dose immunization groups, the group F1-40 μg induced a statistically higher antibody titre than the group F1-20 μg. Complete protection was observed for animals immunized with purified F1 antigen by s.c. route. In contrast, the control mice immunized with aluminum hydroxide suc-cumbed to a same dose of Y. pestis 141 challenge. Conclusion This purification strategy is a simple and ef-fective, and can be operated in a large scale. Native F1 antigen extracted from Y. pestis EV76 is highly im-munagenic, and can be used as a key antigen component to develop sub-unit vaccine of plague.