Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes

AIM

A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high-binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method.

METHODS AND RESULTS

ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, noncell-based mannose reduced the activity of ConA in inhibiting biofilms.

CONCLUSIONS

ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA.

SIGNIFICANCE AND IMPACT OF THE STUDY

ConA can be used as a promising anti-adherent and antibiofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins.

[Various choices of reconstructing the left subclavicular artery to extend the proximal landing zone thoracic endovascular aortic repair]

Thoracic endovascular aortic repair (TEVAR) has become the preferred treatment for Stanford type B aortic dissection. Covered the left subclavian artery (LSA) directly may cause corresponding complications in Stanford type B aortic dissection with unfavourable proximal landing zone. TEVAR can be successfully implemented by reconstructing LSA to expand the proximal landing zone. Currently, the methods of reconstructing LSA mainly include hybridization technology (carotid-subclavian artery transposition), chimney technology (including branch stent technology) and fenestration (or slot technology), etc. These techniques are all valid for aortic dissection that needs to reconstructing LSA. The choices and applications of these techniques should follow the individualized principles.

[A single center large cohort study on perioperative complications of carotid endarterectomy of 547 cases]

Objective: To analyze the risk factors of perioperative complications within 30 days of carotid endarterectomy(CEA) in the treatment of carotid atherosclerosis stenosis(CAS) during 2011-2017, and to discuss the techniques for reducing the perioperative complication rates. Methods: From August 2011 to August 2017, 486 patients with CAS were retrospective included, and 61 of them underwent bilateral CEA, with a total of 547 cases of CEA included. Perioperative complications were collected within 30 days after operation, and the risk factors related to perioperative complications were analyzed by statistical analysis. Results: In total 547 cases, 12 cases had a postoperative stroke, while 1 case died. A total of 7 cases underwent cranial nerve injury, and 5 cases had an incision related complications. In chi-square test analysis, data suggested that there was a significant difference in the incidence of complications in patients with heart disease, preoperative neurological score difference, contralateral carotid serious stenosis or occlusion and intraoperative shunt in CCA/ICA technique application (P<0.05). In the multivariate Logistic regression, it suggested that poor preoperative neurological score and contralateral carotid serious stenosis or occlusion were independent risk factors for perioperative stroke and death. Conclusion: Our results showed that CEA is effective to prevent stroke and treat patients with CAS. Patients with poor preoperative neurological score and contralateral carotid serious stenosis or occlusion may increase the risk of postoperative stroke rates.

bmp3 is Required for Integrity of Blood Brain Barrier by Promoting Pericyte Coverage in Zebrafish Embryos

BACKGROUND

The compromise of blood brain barrier (BBB) integrity is often associated with human hemorrhage stroke and neurodegeneration diseases, including retina diseases, such as age-related macular degeneration and diabetic retinopathy. Brain pericytes play pivotal roles in regulation and maintenance of BBB integrity. However, the mechanisms underlying brain pericyte development to establish BBB integrity remain unclear.

METHODS

Zebrafish transgenic lines Tg(flk1:GFP; gata1:dsRed), Tg(flk1:GFP), Tg(fli1:GFP) and Tg(BRE:GFP) were used in this work. The functional studies of bmp3 were performed by mopholino oligonucleotide (MO) injection, dye-based permeability assay, RT-PCR, in vivo imaging, immunofluorescence staining and statics analysis.

RESULTS

Here we report that bmp3 regulates BBB integrity in zebrafish brain by promoting pericyte development. Knockdown of bmp3 with injection of bmp3-MO causes intracerebral hemorrhage in zebrafish embryos. Meanwhile, disruption of bmp3 function by bmp3-MO injection impairs cerebral pericyte coverage in zebrafish embryos. Mechanistically, knockdown of bmp3 disrupts the pattern and activities of BMP signaling in zebrafish brain, thus probably disrupting the balance of TGFβ/BMP signaling in zebrafish embryos.

CONCLUSION

In summary, our data shows that bmp3 regulates BBB integrity potentially by promoting pericyte development.

[Serologic surveillance indicators analysis among syphilis-infected pregnant women in East China]

Objective: To analyze serologic surveillance indicators during pregnancy among syphilis-infected women who delivered in 2013 in East China. Methods: Data were from national 'Information System of Prevention of Mother-to-child Transmission of HIV, syphilis and HBV Management' and in total 5 206 syphilis-infected pregnant women who delivered in 2013 and in East China were involved in the analysis. Information on demographic characters, laboratory tests, and treatment regimens were collected. The maternal non-treponemal testing surveillance and titer distribution were described and compare the proportions between pregnant women receiving standard testing and non-standard testing, taking baseline testing and testing before delivery or at the third trimester. Multivariate logistic regression model was analyzed using maternal titer control as dependent variable, using prior history of syphilis infection, syphilis stages, titer, gestational weeks of treatment initiation and treatment regimens as independent variables in 3 940 pregnant women with both baseline testing results and testing results before delivery or at the third trimester. Results: The ages of the 5 206 syphilis infected pregnant women were (28.1±5.8) years old. The numbers of women received penicillin treatment, other treatment regimens and no treatment were 2 967 (57.0%), 281 (5.4%), and 1 958 (37.6%), respectively. The number of women with maternal seroconversion, 4-fold or greater titer decline, or titer increase were 349 (6.7%), 251 (4.8%) and 28 (0.5%). Multivariate analysis results showed that compared with pregnant women with prior history of syphilis, the OR(95%CI) for maternal titer control was 1.49 (1.18-1.88) among those with syphilis-infection history. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks or received no treatment. Compared with pregnant women received penicillin treatment, the OR (95%CI) for maternal titer control among those received non-penicillin treatment and those received no treatment were 2.35 (1.46-3.76) and 1.55 (1.13-2.12), respectively. Conclusion: In East China, the proportion of women achieved seroconversion or 4-fold or greater titer decline during pregnancy was very low. Pregnant women with no prior history of syphilis infection, early maternal initiation of treatment, and penicillin treatment were more likely to reach maternal titer control.

Molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus)

Ghrelin is a novel growth hormone (GH)-releasing peptide, which has been identified as an endogenous ligand for the GH-sretagogue receptor. The sequence and expression of ghrelin has been determined in many species. In this study, to reveal the molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus), the full-length DNA and cDNA encoding ghrelin were cloned from reindeer stomach using genome walking and rapid amplification of complementary deoxyribonucleic acid ends (RACE). The expression of ghrelin in almost all tissues was examined by real-time quantitative PCR (RT-qPCR). The 4076 bp amplicon of the ghrelin gene consisting of 4 exons and 3 introns was cloned from reindeer. Results of cDNA cloning and sequence analysis revealed that the full-length ghrelin cDNA was composed of 539 bp that included a 5'-untranslated region (46 bp), an open reading frame (ORF) (351 bp), and a 3'-untranslated region (142 bp). In addition, ghrelin was expressed in the all tissues examined, with the expression in the abomasum significantly higher than that in other tissues (p<0.05), followed by the pancreas, duodenum, testis and oesophagus. The results show that the expression of ghrelin in the reindeer gastrointestinal tract is extensive, suggesting its may have a role in regulating the digestive function.

[A long term effect on speech recognition in the patients with simultaneous bilateral cochlear implants]

Objective: To investigate an effect on speech recognition after bilateral cochlear implants(CI) simultaneously. Methods: Nine subjects who underwent bilateral CI operation simultaneously in Peking Union Hospital in 2007 were assigned as bilateral group, another 9 subjects with unilateral CI were chosen as unilateral group according to the age, gender, duration of deafness. Hearing threshold, speech recognition of phrases, disyllabic words, single word in quiet and noise environment were calculated, respectively. Three different sound source positions were set up to simulate the three effects of binaural hearing (head shadow, binaural redundancy and binaural squelch) in noise environment. The speech signal intensity was 70 dBSPL, the signal to noise ratio (SNR) was 0 dB, + 4 dB, + 8 dB, and the speech recognition of phrases were examined in bilateral CI group. All the data was analyzed by SPSS 19.0 software. Results: In quiet environment, the average aid-hearing threshold was significantly reduced as (7.2±3.0)dB in bilateral CI group compared to unilateral CI group(P<0.05). However, the speech recognition of phrases, disyllabic words, and single word in quiet and noise environment did not show significant differences between bilateral CI and unilateral CI groups (P>0.05). In the testing under noise environment, the speech recognition of bilateral CI group was significantly higher than that of unilateral CI group (P<0.05). In the estimation of noise environment (SNR=+ 8), the phrase test and speech recognition of head shadow model in bilateral groups were significantly better than that of unilateral group (P<0.01). Further, bilateral CI group showed statistical significances in binaural redundancy and binaural squelch models(P<0.01), there was statistically significant were also found difference between two groups (P<0.01); Bilateral CI group did not reveal significant difference compared with unbilateral CI group in binaural squelch model(P>0.05). Under different signal-to-noise ratio (SNR=+ 8, + 4) noise environment, all the three given models in bilateral CI group show higher signal-to-noise ratio, higher speech recognition rate (Independent-Samples t test, P<0.01). In addition, head shadow model presented negative influences on speech recognition rate compared with binaural redundancy and binaural squelch model by SNR(P<0.05). SNR influences on binaural redundancy and binaural squelch model were almost identical, F=0.371, P=0.549. Conclusion: The subjects who underwent simultaneous bilateral cochlear implantation could significantly reduce aid-hearing threshold, and greatly improve the speech recognition of phrases, disyllabic words, and single word under noise environment.

A Simple Method of Fabricating Graphene-Polymer Conductive Films

In this study, polydimethylsiloxane and graphene were used to fabricate surface electrodes for electrocardiographic (ECG) sensing. A simple and inexpensive method was developed to fabricate graphene-based polymer films. In this method, graphene was inlaid in polydimethylsiloxane by polymer infiltration. The polymer films were successfully used in ECG measurements and performed as well as conventional silver/silver chloride wet electrodes. Few motion artifacts were observed with the graphene films when body postures were changed and during walking. The presented approach is low-cost and suitable for mass production, holding great promise in fabricating polymer electrodes for medical monitoring.