Cloning approach and functional analysis of anti-intimin single-chain variable fragment (scFv)

<p>Abstract</p> <p>Background</p> <p>Intimin is an important virulence factor involved in the pathogenesis of enteropathogenic <it>Escherichia coli </it>(EPEC) and enterohemorrhagic <it>Escherichia coli </it>(EHEC). Both pathogens are still important causes of diarrhea in children and adults in many developing and industrialized countries. Considering the fact that antibodies are important tools in the detection of various pathogens, an anti-intimin IgG2b monoclonal antibody was previously raised in immunized mice with the conserved sequence of the intimin molecule (int_388-667). In immunoblotting assays, this monoclonal antibody showed excellent specificity. Despite good performance, the monoclonal antibody failed to detect some EPEC and EHEC isolates harboring variant amino acids within the 338-667 regions of intimin molecules. Consequently, motivated by its use for diagnosis purposes, in this study we aimed to the cloning and expression of the single-chain variable fragment from this monoclonal antibody (scFv).</p> <p>Findings</p> <p>Anti-intimin hybridoma mRNA was extracted and reversely transcripted to cDNA, and the light and heavy chains of the variable fragment of the antibody were amplified using commercial primers. The amplified chains were cloned into <it>pGEM-T Easy </it>vector. Specific primers were designed and used in an amplification and chain linkage strategy, obtaining the scFv, which in turn was cloned into pAE vector. <it>E. coli </it>BL21(DE3)pLys strain was transformed with pAE scFv-intimin plasmid and subjected to induction of protein expression. Anti-intimin scFv, expressed as inclusion bodies (insoluble fraction), was denatured, purified and submitted to refolding. The protein yield was 1 mg protein per 100 mL of bacterial culture. To test the functionality of the scFv, ELISA and immunofluorescence assays were performed, showing that 275 ng of scFv reacted with 2 mg of purified intimin, resulting in an absorbance of 0.75 at 492 nm. The immunofluorescence assay showed a strong reactivity with EPEC E2348/69.</p> <p>Conclusion</p> <p>This study demonstrated that the recombinant anti-intimin antibody obtained is able to recognize the conserved region of intimin (Int_388-667) in purified form and the EPEC isolate.</p

The Repetitive Cytoskeletal Protein H49 of Trypanosoma cruzi Is a Calpain-Like Protein Located at the Flagellum Attachment Zone

Background: Trypanosoma cruzi has a single flagellum attached to the cell body by a network of specialized cytoskeletal and membranous connections called the flagellum attachment zone. Previously, we isolated a DNA fragment (clone H49) which encodes tandemly arranged repeats of 68 amino acids associated with a high molecular weight cytoskeletal protein. in the current study, the genomic complexity of H49 and its relationships to the T. cruzi calpain-like cysteine peptidase family, comprising active calpains and calpain-like proteins, is addressed. Immunofluorescence analysis and biochemical fractionation were used to demonstrate the cellular location of H49 proteins.Methods and Findings: All of H49 repeats are associated with calpain-like sequences. Sequence analysis demonstrated that this protein, now termed H49/calpain, consists of an amino-terminal catalytic cysteine protease domain II, followed by a large region of 68-amino acid repeats tandemly arranged and a carboxy-terminal segment carrying the protease domains II and III. the H49/calpains can be classified as calpain-like proteins as the cysteine protease catalytic triad has been partially conserved in these proteins. the H49/calpains repeats share less than 60% identity with other calpain-like proteins in Leishmania and T. brucei, and there is no immunological cross reaction among them. It is suggested that the expansion of H49/calpain repeats only occurred in T. cruzi after separation of a T. cruzi ancestor from other trypanosomatid lineages. Immunofluorescence and immunoblotting experiments demonstrated that H49/calpain is located along the flagellum attachment zone adjacent to the cell body.Conclusions: H49/calpain contains large central region composed of 68-amino acid repeats tandemly arranged. They can be classified as calpain-like proteins as the cysteine protease catalytic triad is partially conserved in these proteins. H49/calpains could have a structural role, namely that of ensuring that the cell body remains attached to the flagellum by connecting the subpellicular microtubule array to it.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Beca Presidente de la Republica-ChileUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Escola Paulista Med, São Paulo, BrazilUniv Antofagasta, Lab Bioquim, Dept Biomed, Antofagasta, ChileUniv Bandeirante São Paulo, São Paulo, BrazilUniv Brasilia, Dept Biol Celular, Inst Biol, Brasilia, DF, BrazilFiocruz MS, Ctr Pesquisa Rene Rachou CPqRR, Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Escola Paulista Med, São Paulo, BrazilWeb of Scienc

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Case–control study of pathogens involved in piglet diarrhea

Abstract\ud \ud Background\ud Diarrhea in piglets directly affects commercial swine production. The disease results from the interaction of pathogens with the host immune system and is also affected by management procedures. Several pathogenic agents such as Campylobacter spp., Clostridium perfringens, Escherichia coli, Salmonella spp., group A rotavirus (RV-A), coronaviruses (transmissible gastroenteritis virus; porcine epidemic diarrhea virus), as well as nematode and protozoan parasites, can be associated with disease cases.\ud \ud \ud Results\ud All bacterial, viral, protozoan, and parasitic agents here investigated, with the exception of Salmonella spp. as well as both coronaviruses, were detected in varying proportions\ud in piglet fecal samples, and positive animals were equally distributed between case and control groups. A statistically significant difference between case and control groups was found only for Cystoisospora suis (p = 0.034) and Eimeria spp. (p = 0.047). When co-infections were evaluated, a statistically significant difference was found only for C. perfringens β2 and C. suis (p = 0.014).\ud \ud \ud Conclusions\ud The presence of pathogens in piglets alone does not determine the occurrence of diarrhea episodes. Thus, the indiscriminate use of antibiotic and anthelminthic medication should be re-evaluated. This study also reinforces the importance of laboratory diagnosis and correct interpretation of results as well as the relevance of control and prophylactic measures.This work was supported by São Paulo Research Foundation (FAPESP)\ud (project number 2010/00390-5 and scholarship support 2011/01563-3 and\ud 2011/19666-3)

Case–control study of pathogens involved in piglet diarrhea

Abstract\ud \ud Background\ud Diarrhea in piglets directly affects commercial swine production. The disease results from the interaction of pathogens with the host immune system and is also affected by management procedures. Several pathogenic agents such as Campylobacter spp., Clostridium perfringens, Escherichia coli, Salmonella spp., group A rotavirus (RV-A), coronaviruses (transmissible gastroenteritis virus; porcine epidemic diarrhea virus), as well as nematode and protozoan parasites, can be associated with disease cases.\ud \ud \ud Results\ud All bacterial, viral, protozoan, and parasitic agents here investigated, with the exception of Salmonella spp. as well as both coronaviruses, were detected in varying proportions\ud in piglet fecal samples, and positive animals were equally distributed between case and control groups. A statistically significant difference between case and control groups was found only for Cystoisospora suis (p = 0.034) and Eimeria spp. (p = 0.047). When co-infections were evaluated, a statistically significant difference was found only for C. perfringens β2 and C. suis (p = 0.014).\ud \ud \ud Conclusions\ud The presence of pathogens in piglets alone does not determine the occurrence of diarrhea episodes. Thus, the indiscriminate use of antibiotic and anthelminthic medication should be re-evaluated. This study also reinforces the importance of laboratory diagnosis and correct interpretation of results as well as the relevance of control and prophylactic measures.This work was supported by São Paulo Research Foundation (FAPESP)\ud (project number 2010/00390-5 and scholarship support 2011/01563-3 and\ud 2011/19666-3)

Secretion of Novel SEL1L Endogenous Variants Is Promoted by ER Stress/UPR via Endosomes and Shed Vesicles in Human Cancer Cells

We describe here two novel endogenous variants of the human endoplasmic reticulum (ER) cargo receptor SEL1LA, designated p38 and p28. Biochemical and RNA interference studies in tumorigenic and non-tumorigenic cells indicate that p38 and p28 are N-terminal, ER-anchorless and more stable relative to the canonical transmembrane SEL1LA. P38 is expressed and constitutively secreted, with increase after ER stress, in the KMS11 myeloma line and in the breast cancer lines MCF7 and SKBr3, but not in the non-tumorigenic breast epithelial MCF10A line. P28 is detected only in the poorly differentiated SKBr3 cell line, where it is secreted after ER stress. Consistently with the presence of p38 and p28 in culture media, morphological studies of SKBr3 and KMS11 cells detect N-terminal SEL1L immunolabeling in secretory/degradative compartments and extracellularly-released membrane vesicles. Our findings suggest that the two new SEL1L variants are engaged in endosomal trafficking and secretion via vesicles, which could contribute to relieve ER stress in tumorigenic cells. P38 and p28 could therefore be relevant as diagnostic markers and/or therapeutic targets in cancer

CCQM-K55.b (Aldrin) : Final report: october 2012. CCQM-K55.b key comparison on the characterization of organic substances for chemical purity

Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.b, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2010/2011. Nineteen national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of aldrin present as the main component in the comparison sample for CCQM-K55.b which consisted of technical grade aldrin obtained from the National Measurement Institute Australia that had been subject to serial recrystallization and drying prior to sub-division into the units supplied for the comparison. Aldrin was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300 Da to 500 Da] and low polarity (pKOW < −2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC). The key comparison reference value (KCRV) for the aldrin content of the material was 950.8 mg/g with a combined standard uncertainty of 0.85 mg/g. The KCRV was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.3% to 0.6% using a mass balance approach and 0.5% to 1% using a qNMR method. The major analytical challenge posed by the material proved to be the detection and quantification of a significant amount of oligomeric organic material within the sample and most participants relying on a mass balance approach displayed a positive bias relative to the KCRV (overestimation of aldrin content) in excess of 10 mg/g due to not having adequate procedures in place to detect and quantify the non-volatile content—specifically the non-volatile organics content—of the comparison sample. There was in general excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content and the residual solvent content of the sample. The comparison demonstrated the utility of 1H NMR as an independent method for quantitative analysis of high purity compounds. In discussion of the participant results it was noted that while several had access to qNMR estimates for the aldrin content that were inconsistent with their mass balance determination they decided to accept the mass balance result and assumed a hidden bias in their NMR data. By contrast, laboratories that placed greater confidence in their qNMR result were able to resolve the discrepancy through additional studies that provided evidence of the presence of non-volatile organic impurity at the requisite level to bring their mass balance and qNMR estimates into agreement.Fil: Westwood, Steven. Bureau International des Poids et Mesures (BIPM); FranciaFil: Josephs, Ralf. Bureau International des Poids et Mesures (BIPM); FranciaFil: Choteau, Tiphaine. Bureau International des Poids et Mesures (BIPM); FranciaFil: Daireaux, Adeline. Bureau International des Poids et Mesures (BIPM); FranciaFil: Mesquida, Charline. Bureau International des Poids et Mesures (BIPM); FranciaFil: Wielgosz, Robert. Bureau International des Poids et Mesures (BIPM); FranciaFil: Rosso, Adriana. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Ruiz de Arechavaleta, Mariana. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Davies, Stephen. National Measurement Institute (NMIA); AustraliaFil: Wang, Hongjie. National Measurement Institute (NMIA); AustraliaFil: Pires do Rego, Eliane Cristina. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Marques Rodrigues, Janaína. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: de Freitas Guimarães, Evelyn. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Barreto Sousa, Marcus Vinicius. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Monteiro, Tânia Maria. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Alves das Neves Valente, Laura. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Marques Violante, Fernando Gustavo. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Rubim, Renato. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Almeida, Ribeiro. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Baptista Quaresma, Maria Cristina. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Nogueira, Raquel. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Windust, Anthony. Institute for National Measurement Standards. National Research Council Canada (NRC-INMS); CanadáFil: Dai, Xinhua. National Institute of Metrology (NIM); ChinaFil: Li, Xiaomin. National Institute of Metrology (NIM); ChinaFil: Zhang, Wei. National Institute of Metrology (NIM); ChinaFil: Li, Ming. National Institute of Metrology (NIM); ChinaFil: Shao, Mingwu. National Institute of Metrology (NIM); ChinaFil: Wei, Chao. National Institute of Metrology (NIM); ChinaFil: Wong, Siu-kay. Government Laboratory of Hong Kong SAR (GLHK); ChinaFil: Cabillic, Julie. Laboratoire National de Métrologie et d’Essais (LNE); FranciaFil: Gantois, Fanny. Laboratoire National de Métrologie et d’Essais (LNE); FranciaFil: Philipp, Rosemarie. Bundesanstalt für Materialforschung (BAM); AlemaniaFil: Pfeifer, Dietmar. Bundesanstalt für Materialforschung (BAM); AlemaniaFil: Hein, Sebastian. Bundesanstalt für Materialforschung (BAM); AlemaniaFil: Klyk-Seitz, Urszula-Anna. Bundesanstalt für Materialforschung (BAM); AlemaniaFil: Ishikawa, Keiichiro. National Metrology Institute of Japan (NMIJ); JapónFil: Castro, Esther. Centro Nacional de Metrología (CENAM); MéxicoFil: Gonzalez, Norma. Centro Nacional de Metrología (CENAM); MéxicoFil: Krylov, Anatoly. D. I. Mendeleev Institute for Metrology (VNIIM); RusiaFil: Lin, Teo Tang. Health Sciences Authority (HSA); SingapurFil: Kooi, Lee Tong. Health Sciences Authority (HSA); SingapurFil: Fernandes-Whaley, M. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Prévoo, D. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Archer, M. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Visser, R. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Nlhapo, N. National Metrology Institute of South Africa (NMISA); SudáfricaFil: de Vos, B. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Ahn, Seonghee. Korea Research Institute of Standards and Science (KRISS); Corea del SurFil: Pookrod, Preeyaporn. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Wiangnon, Kanjana. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Sudsiri, Nittaya. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Muaksang, Kittiya. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Cherdchu, Chainarong. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Gören, Ahmet Ceyhan. National Metrology Institute (TUBITAK UME); TurquíaFil: Bilsel, Mine. National Metrology Institute (TUBITAK UME); TurquíaFil: LeGoff, Thierry. LGC Limited; Reino UnidoFil: Bearden, Dan. National Institute of Standards and Technology (NIST); Estados UnidosFil: Bedner, Mary. National Institute of Standards and Technology (NIST); Estados UnidosFil: Duewer, David. National Institute of Standards and Technology (NIST); Estados UnidosFil: Hancock, Diane. National Institute of Standards and Technology (NIST); Estados UnidosFil: Lang, Brian. National Institute of Standards and Technology (NIST); Estados UnidosFil: Lippa, Katrice. National Institute of Standards and Technology (NIST); Estados UnidosFil: Schantz, Michele. National Institute of Standards and Technology (NIST); Estados UnidosFil: Sieber, John. National Institute of Standards and Technology (NIST); Estados Unido