Nature is abundant in protein scaffolds.By selecting suitable protein scaffold,display and screening methods,the rational and constrained random peptide library(RPL)can be constructed.Compared with the non-constrained RPL,it offered more opportunities for obtaining novel protein structures and more higher affinity ligands against the target molecules.At present,the protein scaffold constrained RPLs have been shown great potential in applications such as target selection,basic research,clinical diagnosis,medical therapy and so on.It is systematically introduced the structure bases,classification and construction of constrained RPL based on scaffolds,as well the recent great advances of application in selection against target molecules with S-S constrained scaffolds,antibodies,Zinc finger protein,Z domain,FN3 domain as important examples.

BACKGROUND:Epidural scar after laminectomy is one important reason for the secondary spinal stenosis, and local application ofSanqi sodium hyaluronate gel can prevent epidural scar adhesion after laminectomy. OBJECTIVE: To study the effects ofSanqisodium hyaluronate gel on α-smooth muscle actin expression in the process of rabbit's epidural scar formation. METHODS: In this study, there were ninety-six rabbits which were randomized into four groups and given 0.5 mL normal saline, 0.5 mLSanqi concentrated solution, 0.5 mL sodium hyaluronate and 0.5 mLSanqisodium hyaluronate gel around the dura. At 1, 2, 4, 8 weeks after treatment, immunohistochemistry staining was employed for analysis of α-smooth muscle actin expression. RESULTS AND CONCLUSION:At the end of weeks 1 and 2, the expression of α-smooth muscle actin antibody in the normal saline group was significantly higher than that in the other three groups (P < 0.01 orP < 0.05), but there were no significant differences among the Sanqi, sodium hyaluronate andSanqisodium hyaluronate gel groups (P> 0.05). At weeks 4 and 8, the expression of α-smooth muscle actin antibody in theSanqi sodium hyaluronate gel group was significantly lower than that in the other three groups (P < 0.01 orP < 0.05), and there was no significant difference among the latter three groups (P > 0.05). These findings suggest thatSanqi sodium hyaluronate gel can inhibit the expression of α-smooth muscle actin, and thus ease scar contracture.

The discovery of microRNAs (miRNAs) has introduced a new paradigm into gene regulatory systems. Since inception, computational methods have been an invaluable tool complementing experimental approaches, and many discoveries have been obtained through combination of experimental and computational approaches. The knowledge that has been accumulated about the principles of miRNAs and target recognition were reviewed. The currently available computational methodologies and software for prediction of miRNA and their target genes also have been discussed.

Selection and affinities of Cd binding peptides were assayed by phage random dodecapeptide library and affinity chromatography. Two Cd binding peptides were obtained, it was found that the affinities of Cu~ 2+ ,Co~ 2+ ,Zn~ 2+ ,Ni~ 2+ for Cd binding peptides were higher than that of Cd~ 2+ and Cr~ 2+ after detection of the amplified Cd binding peptides displayed phages to different heavy metal-charged resins; the detoxification of E.coli to Ni~ 2+ and Cd~ 2+ was enhanced when infected by Cd binding peptide displayed phages as compared with those of the control. The interaction of Cd binding peptide displayed phages with heavy metals charged resins was also observed under microscope. The work would be of great value and consequences for the study of interaction between heavy metals and proteins(peptides), as well as thedetoxification and bioremediation of heavy metals.

Abstract: Objective　To investigate the molecular characteristics and drug resistance of non-O1/non-O139 Vibrio cholerae in Zhongshan City, and to provide laboratory basis for cholera prevention and control. Methods　The strains of non-O1/non-O139 Vibrio cholerae isolated from sporadic patients and aquatic products from 2015 to 2021 in Zhongshan city were collected. The identification and cluster analysis of the strains were analyzed by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), the ctxA virulence gene of strains were detected by real-time fluorescence quantitative PCR, the cluster analysis of the strains was analyzed by pulsed-field gel electrophoresis (PFGE), and the drug resistance of the strains were analyzed by microbroth dilution method. Results　From 2015 to 2021, 33 strains of non-O1/non-O139 Vibrio cholerae were isolated from Zhongshan City, including 28 strains from sporadic patients and 5 strains from aquatic products. Through MALDI-TOF-MS identification, 33 strains of non-O1/non-O139 Vibrio cholera can be identified to the level of species, and the identification results were all Vibrio cholerae. Among 33 non-O1/non-O139 Vibrio cholerae strains, 1 strain carried the ctxA virulence gene. The drug-resistant strains accounted for 69.7% (23/33), and the multidrug resistant strains accounted for 18.2% (6/33). A total of 7 kinds of drug resistance spectrum were produced, including 3 kinds of multidrug resistant spectrum, and showed drug resistance to 8 antibiotics, among which the resistance rates to streptomycin, cefazolin and compound sulfamethoxazole were above 30%. The 33 strains of non-O1/non-O139 Vibrio cholerae were divided into 32 PFGE fingerprints with a similarity ranging from 61.7% to 100%. MALDI-TOF-MS cluster analysis divided 33 non-O1/non-O139 Vibrio cholerae strains into two clusters. Conclusions The results of molecular typing of non-O1/non-O139 Vibrio cholerae in Zhongshan City presented diversity, and no significant correlation was found between PFGE and MALDI-TOF-MS cluster analysis. The strains demonstrated various degrees of resistance to certain antibiotics, and there were multidrug-resistant and toxigenic strains. Therefore, it is necessary to alert to the harmfulness of non-O1/non-O139 Vibrio cholerae and enhance monitoring.

Objective To evaluate the CT findings of pancreatic carcinoid tumors.Methods The CT imaging data of five patients with pancreatic carcinoid tumors confirmed by pathology were retrospectively analyzed.Results The tumors ranged in maximum diameter from 2.0 to 11.0 cm with a mean of 6.4 cm. On unenhanced CT,the tumors were slightly hypodense relative to the pancreatic parenchyma,homogenous in 2 cases,and heterogenous in 3 cases.One tumor showed calcification.After contrast material injection, the solid component of the tumor showed marked heterogenous enhancement on the arterial phase scanning in 3 cases,and mild heterogenous enhancement in 2 cases.The degree of tumor enhancement was less intense than the surrounding pancreatic parenchyma due to necrosis of various degree,which led to the cystic appearance of the tumor in 1 ease.On the portal phase scanning,all tumors showed marked enhancement similar to that of the pancreatic parenchyma.On the delayed phase scanning,the degree of enhancement was more intense than the surrounding pancreatic parenchyma in 1 case.Liver metastases with retroperitoneal lymphadenopathy and peripancreatic vessels invasion were seen in 1 case.No dilatation of the biliary tract or pancreatic duct was present.Conclusion The CT features of pancreatic carcinoid tumors included infrequent dilatation of the biliary tract or pancreatic duct and unusual vascular involvement,calcification within the mass,marked enhancement similar to that of the surrounding pancreatic parenchyma during the portal phase scanning and more intense during the delayed phase scanning.

OBJECTIVETo investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH).

METHODSTotally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Y were analyzed.

RESULTSAmong 51 embryos, 16 (31.4%) were mosaic, 12 (23.5%) were chaotic, and the remaining were either normal (27.5%) or non-mosaic abnormal (17.6%). The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from 12.5% in embryos

CONCLUSIONMosaicism is common in human preimplantaion embryos, which may be one of the important factors affecting the success rates in IVF-ET. Most of the chromosomal abnormalities can be identified by two sequential rounds of FISH.

Aneuploidy ; Blastocyst ; Chromosomes, Human ; Embryo Transfer ; Female ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Mosaicism ; chemically induced ; embryology ; Preimplantation Diagnosis

BACKGROUNDThe efficiency of traditional cryopreservation of human embryonic stem (ES) cells is low, and there have been few attempts to prove new cryopreservation methods effective. This study was designed to evaluate the efficiency of cryopreservation of human ES cells using vitrification method.

METHODSHuman ES cells clumped from an identical cell line were randomly allocated to be cryopreserved by vitrification or by slow freezing. The recovery rates, the growth and differentiation potential of thawed human ES cells were compared between these two groups. The pluripotency of human ES cells after thawing was identified.

RESULTSEighty-one point nine percent (59/72) of human ES cell clumps were recovered after vitrification, while only 22.8% (16/70) were recovered after slow freezing (P < 0.01). The colonies after vitrification manifested have not only faster growth but also a lower level of differentiation when compared to colonies subjected to the slow freezing protocol. However, the rates of growth and differentiation in undifferentiated colonies from both groups were identical to the rates in those of non-cryopreserved stem cells after a prolonged culture period. Passage 6 of vitrified human ES cells retained the properties of pluripotent cells, a normal karyotype and expressed the transcription factor OCT-4, stage specific expressed antigen-4 (SSEA-4) and SSEA-3. Teratoma growth of these cells demonstrated the ability to develop into all three germ layers.

CONCLUSIONSVitrification is effective in cryopreserving human ES cells. During a prolonged culture, human ES cells retain their pluripotency after cryopreservation.

Cell Differentiation ; Cell Survival ; Cryopreservation ; methods ; Embryo, Mammalian ; cytology ; Humans ; Osmotic Pressure ; Stem Cells ; cytology

OBJECTIVETo establish an improved procedure for isolation and identification of epitopes from a random peptide library displayed on the bacterial surface.

METHODSEpitopes were screened from FliTrx random peptide library by a monoclonal antibody 3B9 against HBV-PreS2 protein. The enrichment was monitored in each round. Higher affinity clones were obtained by increasing the washing strength and randomly selected for sequencing and Western blot analysis.

RESULTSClones specifically binding to antibody were enriched in each round. Ten sequences were obtained from sixteen sequenced clones, seven of them contained the common motif RXRGXY with high homogeneity to 135-140 amio acids in HBV-PreS protein and have positive results in Western blot analysis. The other three sequences have no typical motif RXRGXY and showed different Western blot results.

CONCLUSIONSIt's easy and quick to drive epitopes from a random peptide library displayed on the bacterial surface.

Amino Acid Sequence ; Animals ; Antigens, Viral ; immunology ; Bacterial Proteins ; immunology ; Flagellin ; immunology ; Hepatitis B Surface Antigens ; genetics ; immunology ; isolation & purification ; Immunodominant Epitopes ; immunology ; Molecular Sequence Data ; Peptide Library ; Protein Precursors ; genetics ; immunology ; isolation & purification