Silica nanoparticles are novel aqueous additive mitigating heavy metals toxicity and improving the health of African catfish, Clarias gariepinus.

Silica nanoparticles (SiNPs) are among the non-toxic nanoparticles (NPs) that have magnetic capabilities. It is hypothesized that SiNPs may be able to reduce toxic effects exerted by a mixture of lead (Pb) and mercury (Hg) in African catfish Clarias gariepinus. The in vitro magnetic potential of SiNPs to absorb Pb and Hg was tested. Fish (N = 240) were divided into four groups in triplicates for 30 days. The first group served as control and the second group (SiNPs) was exposed to 1/10 of 96 h LC50 of SiNPs (14.45 mg/L). The third group (HMM) was exposed to 1/10 of 96-h LC50 of a mixture of mercury chloride (HgCl2) and lead chloride (PbCl2) equal to 0.04 mg/ L and 23.1 mg/L. The fourth group (SiNPs+ HMM) was exposed to a suspension composed of SiNPs, HgCl2, and PbCl2 at the same concentrations as the third group. Results showed that fish exposed to heavy metals revealed the following consequences; a significant decrease in hematological, immunological (complement-3 and nitric oxide), and antioxidants (total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase) indices, down-regulation of IL-1ß, IL-8, TGF-ß, NF-κß, HSP70, and Hepcidin genes, the highest mortality rate (48.33%), higher values of alkaline phosphatase, alanine, and aspartate aminotransferases, urea, creatinine, and branchial malondialdehyde, marked up-regulation of CC chemokine and CXC chemokines, and high HMs residues levels in muscles. Extensive pathology showed degeneration with diffuse vacuolation of hepatopancreatic cells and hemorrhage in the HMM group. Interestingly, the exposed group to SiNPs and HMM demonstrated a decline of HMs concentration in fish muscles and modulated the abovementioned parameters with the regeneration of histological alterations of liver and gills. Based on the study outcomes, we highlight the importance and the safety of SiNPs as a novel aqueous additive to alleviate HMs toxicity and recommend using SiNPs for enhancing fish performance for sustaining aquaculture without adverting safety of human health by their little accumulation in muscular tissue.

The type III secretion system (T3SS)-Translocon of atypical enteropathogenic Escherichia coli (aEPEC) can mediate adherence

The intimin protein is the major adhesin involved in the intimate adherence of atypicalenteropathogenicEscherichia coli(aEPEC) strains to epithelial cells, but little is knownabout the structures involved in their early colonization process. A previous studydemonstrated that the type III secretion system (T3SS) plays an additional role in theadherence of anEscherichia albertiistrain. Therefore, we assumed that the T3SS couldbe related to the adherence efficiency of aEPEC during the first stages of contactwith epithelial cells. To test this hypothesis, we examined the adherence of sevenaEPEC strains and theireae(intimin) isogenic mutants in the standard HeLa adherenceassay and observed that all wild-type strains were adherent while five isogeniceaemutants were not. The twoeaemutant strains that remained adherent were then usedto generate theeae/escNdouble mutants (encoding intimin and the T3SS ATPase,respectively) and after the adherence assay, we observed that one strain lost itsadherence capacity. This suggested a role for the T3SS in the initial adherence stepsof this strain. In addition, we demonstrated that this strain expressed the T3SS atsignificantly higher levels when compared to the other wild-type strains and that itproduced longer translocon-filaments. Our findings reveal that the T3SS-transloconcan play an additional role as an adhesin at the beginning of the colonization processof aEPEC.

Re-expression of RASSF1A by 5-Aza-CdR Induced Demethylation of the Promoter Region in Human Biliary Tract Carcinoma Cells / 华中科技大学学报（医学）（英德文版）

Hypermethylation of the promoter region is an important mean for the transcriptional repression of a number of cancer-associated genes, and over-expression and/or increased activity of DNA methyltransferase are considered to be the main cause of promoter hypermethylation. In order to further explore the epigenetic mechanism of tumor suppressor gene RASSF1A inactivation,5-aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor, was used to treat the human biliary tract carcinoma cell line QBC-939 at the concentration of 5 μmol/L for 24 h in this study. After the chemical intervention with 5-Aza-CdR, the methylation status in the promoter region of RASSF1A gene was detected by methylation specific PCR (MS-PCR), and the expression alteration of RASSF1A mRNA and protein were observed by RT-PCR and Western Blot respectively. Following the treatment with 5-Aza-CdR, methylaiton status in the promoter region of RASSF1A gene was reversed from methylation to unmethylation. A 280 bp DNA band which represented RASS1FA expression at transcriptional level and a 40 kDa (1kDa=0.9921 ku) protein band which represented RASSF1A expression at protein level were detected by RT-PCR and Western Blot respectively in the experimental group cells and there were no corresponding bands in the control group cells. The experimental results suggest that 5-Aza-CdR can induce demethylation in the promoter region of RASSF1A. It can also reverse epigenetic transcriptional silencing caused by DNA methylation and induce the re-expression of RASSF1A in QBC-939. This study also suggest that the mechanism of RASSF1A inactivation is very closely related to the methylation of the promoter region, which may provide a new epigenetic understanding for tumor related gene inactivation and the pathogenesis of biliary tract carcinoma.

High level expression and purification of 1 C-terminal fragment of merozoite surface protein of Plasmodium falciparum in Pichia pastoris / 中国人兽共患病学报

To obtain an ideal recombinant C-terminal fragment of the merozoite surface protein of Plasmodium falciparum in the Pichia pastoris expression system, the major surface protein-119 (MSP-119) gene sequence bearing the 6-his gene was inserted into expression vector pPIC9k and the target gene was transformed to the susceptible yeast cells GS115 by using electroporation. The multiple inserts were screened and the successfully expressed MSP-119 protein with the relative molecular weight of 12kDa in the supernatants of cell cultures could be detected by SDS-PAGE. Meanwhile, Western blot analysis also demonstrated that this protein reacted with mouse anti-MSP-119 monoclonal antibody, and the expression level of MSP-119 was more than 1.0 g/L. It is concluded that this recombinant protein expressed in the Pichia pastoris expression system resembles the native proteins existed.

Expression and implication of survivin in gallbladder cancer / 中国现代普通外科进展

0.05). Conclusion:The excessive expression of Survivin in gallbladder cancer indicates that Survivin could be not only correlated with the occurrence of carcinoma but an early and common event in gallbladder carcinogenesis. Surviv in will promisingly become a novel tumor marker and can be applied in the clinic al practice for helping the early diagnosis as well as targeting gene therapy fo r gallbladder cancer.

The significance of expression of p16 and c-erbB-2 gene in breast cancer / 中国普通外科杂志

Objective To evaluate the relationship between the clinicopathological factors, prognosis and the expression of p16 and c erbB 2 protein in primary breast cancer. Methods The expression of p16 and c erbB 2 by immunohistochemical method was observed in 50 patients with primary breast cancer and the detection of p16 by polymerase chain reaction(PCR) and the point mutation of p16 by PCR single strand conformational polymorphism(SSCP) were detected in 20 patients with breast cancer. Results Among the cancers, positive expression of p16 protein was found in 17(34.00%) cases, c erbB 2 protein positive expression in 24(48.00%) cases. No homozygous deletion in p16 gene was found. However, exon2 point mutation of p16 gene was found in 1 of 20 breast cancer. The results showed no relationship between p16 expression and clinicopathological factor or prognosis. Positive expressions of c erbB 2 protein were often found in breast cancer with lymph node metastasis(P=0.0237) with a poor 5 year survivalrate(P=0.0169). There was no consistent relationship between the expression of p16 and c erbB 2 protein. Neither p16 nor c erbB 2 protein expression could be as an independent prognostic factor. Conclusions The patients with breast cancer of positive expression of c erbB 2 protein has a high lymph node metastasis rate and a poor survival rate. The point mutation rate of p16 gene is lower in primary breast cancer, and it can be a molecular events in advanced primary breast cancer.

Studies on the function of the encoding gene of TEM-105 type of ?-lactamases / 中国药理学通报

Aim To obtain the encoding gene sequences of TEM-type ?-lactamases produced by 4-strain Klebsiella pneumoniae in Zhejian g Province, identify their genotypes and study some properties of these TEM-typ e ?-lactamases.Methods The encoding genes of TEM-type ?-la ctamases produced by 4 isolates were amplified by PCR. The purified PCR products were ligated with pGEM-T easy vectors, expressed in E. coli DH 5?, and sequenced by Sanger's dideoxy chain termin ation composition method. Compared with anino acid sequences in the GenBank,TEM -types of the ?-lactamases was determined. The genes of TEM ?-lactamases were ligated with pET-28 c vector to express recombinant proteins in E. coli DH 5?. Plasmids were extracted from the p ronucleus expression strains and PCR was performed to determine whether the pron ucleus expression was successful or not. Their phenotypes were determined by ESB Ls phenotype affirmative test. The isoelectric points (pIs) of the recombinant p roteins were determined by isoelectric focus. Conjugation test was performed to determine whether their genes existed in plasmid or chromosome. Results The encoding genes of ?-lactamases were determined as TEM by PCR. It s PCR product had 1 009 nucleotides. The pI of the novel TEM ?-lactamase was 5.4. The enzyme was determined as non-ESBLs by ESBLs phenotype affirmative tes t.Transconjugants were successfully selected from the paternal producers in conj ugation tests. The TEM-type ?-lactamase produced by 4 strains was determined as TEM-105(AF516720) by GenBank. Conclusion The ?-lactamase produced by 4-strain K. pneumoniae from 4 patients in Zhejiang Province was TEM-105. It was the first report of TEM-105 type ?-lactamase produced by 4-st ain K. pneumoniae from China in the world.

Promotion of morphine on rat purine nucleotides catabolism and its possible mechanisms / 中国药理学通报

AIMTo investigate the effect of morp hine on purine nucleotides catabolism and its possible mechanisms. METHO DSRats were administered with morphine by intraperitoneal injection with increasing dose to develop ad diction model. The determination of uric acid concentration in plasma and the ac tivities of xanthine oxidase (XO) in the plasma and the small intestine were per formed. RT-PCR was used to examine the expressing level of key enzyme of purine nucleotides catabolism,XO mRNA. ?-actin was used as control gene in RT-PCR s tudy. RESULTSThe concentration of uric acid in plasma was sign ificantly increased in morphine-pretreated rats compared with control(P

EXPRESSION OF SOLUBLE HUMAN ScFv AGAINST CORE PROTEIN OF HEPATITIS C VIRUS IN E COLI / 解放军医学杂志

To construct expressive vector for human ScFv against core protein of hepatitis C virus (HCV core ScFv),and to express soluble HCV core ScFv in E.coli JM109. Using phage display technique, the recombinant phages were panned by recombinant core antigen which was coated in a microtiter plate, and after five rounds of biopanning, 86 clones were identified specific to core antigen. 750 bp fragment could be released from the plasmid of positive phage clones, and the sequence analysis indicated that we have obrained the ScFv DNA fragment. Then DNA fragment was inserted into the expressive vector pCANTAB5E, and E. coli host JM109 was transformed and induced by IPTG. The specificity of ScFv in the culture medium was evaluated by enzyme linked immunosorbent assay (ELISA).The molecular weight of expressed HCV core ScFv protein is 28 000 dalton as determined with the aid of SDS polyacrymide gel electrophoresis (PAGE). The expressed HCV core ScFv protein will be useful in the immunohistochemical study of liver tissue from patients with hepatitis C and gene therapy against HCV infection.