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1.
Behav Sci (Basel) ; 14(4)2024 Apr 09.
Article in English | MEDLINE | ID: mdl-38667101

ABSTRACT

Guided by the theory of planned behavior, this study aimed to determine the influence of Physical Education (PE) teachers' attitudes, their perceived behavioral control, and the influence of subjective norms on their intention and constraints (intrapersonal, interpersonal, and structural) to offer a high-quality class based on best practices to deliver PE lessons online during the COVID-19 pandemic. This cross-sectional, multi-country survey study recruited PE teachers from five countries (China, Malaysia, the Philippines, Turkey, and the United States). A total of 928 online questionnaires were used in the analysis. In terms of the overall intention to teach online, our findings showed that American and Filipino teachers had higher levels of intention to continue teaching online. In contrast, Turkish, Malaysian, and Chinese teachers showed a lower interest. Moreover, Malaysian teachers had more intrapersonal constraints while the teachers in the other four countries were not as restrained intrapersonally. The results highlight the significant influence of perceived behavioral control and attitudes on PE teachers' intention to deliver online courses. Constraints to online teaching had a considerably large negative impact on attitudes, subjective norms, and perceived behavioral control. Based on the results, the proposed extension to the theory of planned behavior was an appropriate framework for understanding the behavioral intent of PE teachers.

2.
Res Q Exerc Sport ; : 1-10, 2024 Jan 19.
Article in English | MEDLINE | ID: mdl-38241175

ABSTRACT

Purpose: This study aimed to investigate how teachers' socialization experiences influence their perceptions of and responses to bullying. Methods: Thirty in-service physical education teachers were recruited to participate. One semi-structured, individual interview was conducted with each participant lasting approximately 60 minutes. Data analysis employed inductive and deductive techniques. Results: Two themes emerged that described teachers' perceptions of and responses to bullying. These themes included: (a) socialization experiences and socializing agents influence teachers' perceptions and behaviors in relation to bullying, and (b) teachers have developed strategies to address bullying but also experience significant challenges. Discussion: The current study suggests that while enrolled in a physical education teacher education program, preservice teachers should be provided greater knowledge about and strategies for addressing bullying. In-service teachers are encouraged to pursue professional development that increases their self-efficacy in managing bullying.

3.
J Cogn Enhanc ; : 1-10, 2023 Jun 05.
Article in English | MEDLINE | ID: mdl-37363056

ABSTRACT

During the summer months, school aged children experience a loss in academic gains made over the course of the school year, as well as engage in poorer health behaviors such as decreased physical activity and poor diet that can lead to excess weight gain. This study aimed to assess changes in body composition, fitness, and cognitive abilities in children from low-income households after a summer physical activity program and explored whether time spent in moderate to vigorous physical activity (MVPA) was related to these changes. Participant's (N = 77) body composition, aerobic fitness (i.e., PACER), and cognitive function (i.e., modified flanker task) were measured during week 1 and week 3. MVPA was collected via hip accelerometer worn during program hours. Paired t-tests and regression analyses were conducted to determine changes between week 1 and 3, whether participation was related to changes in fitness, adiposity, and cognitive function. T-tests revealed significant changes in PACER score (10.71 ± 7.72 to 13.301 ± 10.68; p < 0.001) and incongruent accuracy on the flanker task (65.94% ± 23.83 to 69.00% ± 21.89; p < 0.006), however no significant change in BMI-for-age percentile or body fat percentage was detected. Additionally, regression analyses revealed no significant relationship between change in MVPA or attendance, and changes in PACER, flanker task performance, BMI, or body fat percentage. Children that participated in a summer physical activity program targeted toward children affected by poverty exhibited significant improvements in cardiorespiratory fitness and cognitive abilities, and no changes in body composition.

4.
PLoS Pathog ; 19(4): e1011293, 2023 04.
Article in English | MEDLINE | ID: mdl-37014911

ABSTRACT

The mutation profile of the SARS-CoV-2 Omicron (lineage BA.1) variant posed a concern for naturally acquired and vaccine-induced immunity. We investigated the ability of prior infection with an early SARS-CoV-2 ancestral isolate (Australia/VIC01/2020, VIC01) to protect against disease caused by BA.1. We established that BA.1 infection in naïve Syrian hamsters resulted in a less severe disease than a comparable dose of the ancestral virus, with fewer clinical signs including less weight loss. We present data to show that these clinical observations were almost absent in convalescent hamsters challenged with the same dose of BA.1 50 days after an initial infection with ancestral virus. These data provide evidence that convalescent immunity against ancestral SARS-CoV-2 is protective against BA.1 in the Syrian hamster model of infection. Comparison with published pre-clinical and clinical data supports consistency of the model and its predictive value for the outcome in humans. Further, the ability to detect protection against the less severe disease caused by BA.1 demonstrates continued value of the Syrian hamster model for evaluation of BA.1-specific countermeasures.


Subject(s)
COVID-19 , Animals , Cricetinae , Humans , Convalescence , Mesocricetus , SARS-CoV-2
5.
Adapt Phys Activ Q ; 40(2): 238-256, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-36473480

ABSTRACT

School administrators represent key agents of socialization for teachers within their schools, including adapted physical educators who design and implement instruction for youth with disabilities, often across multiple school sites. The purpose of this study was to understand how adapted physical educators navigate and build relationships with administrators in the schools where they teach. Data were collected through semistructured interviews with 24 adapted physical educators from the U.S. state of California and analyzed using a multiphase approach. Analysis suggested both the importance of and challenges with building effective relationships with administrators. Themes included the following: (a) Administrators do not understand adapted physical education, which impacts programs and students; (b) the importance of relationship building in cultivating principal support; and (c) relationship development requires intentionality, but results in trust and motivation. Results are discussed using role socialization theory, and recommendations for the preparation of both adapted physical educators and school principals are discussed.


Subject(s)
School Teachers , Socialization , Adolescent , Humans , Students , Schools , Physical Education and Training
6.
Environ Microbiol ; 24(10): 4561-4569, 2022 10.
Article in English | MEDLINE | ID: mdl-35837859

ABSTRACT

An imported case of monkeypox was diagnosed in December 2019 in a traveller returning from Nigeria to the UK. Subsequently, environmental sampling was performed at two adjoining single-room residences occupied by the patient and their sibling. Monkeypox virus DNA was identified in multiple locations throughout both properties, and monkeypox virus was isolated from several samples 3 days after the patient was last in these locations. Positive samples were identified following the use of both vacuum and surface sampling techniques; these methodologies allowed for environmental analysis of potentially contaminated porous and non-porous surfaces via real-time quantitative reverse transcriptase PCR analysis in addition to viral isolation to confirm the presence of infection-competent virus. This report confirms the potential for infection-competent monkeypox virus to be recovered in environmental settings associated with known positive cases and the necessity for rapid environmental assessment to reduce potential exposure to close contacts and the general public. The methods adopted in this investigation may be used for future confirmed cases of monkeypox in order to establish levels of contamination, confirm the presence of infection-competent material and to identify locations requiring additional cleaning.


Subject(s)
Monkeypox virus , Mpox (monkeypox) , DNA, Viral , Disease Outbreaks , Humans , Mpox (monkeypox)/diagnosis , Mpox (monkeypox)/epidemiology , Monkeypox virus/genetics , United Kingdom
7.
J Virol ; 95(24): e0083321, 2021 11 23.
Article in English | MEDLINE | ID: mdl-34586862

ABSTRACT

Filoviruses cause high-consequence infections with limited approved medical countermeasures (MCMs). MCM development is dependent upon well-characterized animal models for the assessment of antiviral agents and vaccines. Following large-scale Ebola virus (EBOV) disease outbreaks in Africa, some survivors are left with long-term sequelae and persistent virus in immune-privileged sites for many years. We report the characterization of the ferret as a model for Ebola virus infection, reproducing disease and lethality observed in humans. The onset of clinical signs is rapid, and EBOV is detected in the blood, oral, and rectal swabs and all tissues studied. We identify viral RNA in the eye (a site of immune privilege) and report on specific genomic changes in EBOV present in this structure. Thus, the ferret model has utility in testing MCMs that prevent or treat long-term EBOV persistence in immune-privileged sites. IMPORTANCE Recent reemergence of Ebola in Guinea that caused over 28,000 cases between 2013 and 2016 has been linked to the original virus from that region. It appears the virus has remained in the region for at least 5 years and is likely to have been maintained in humans. Persistence of Ebola in areas of the body for extended periods of time has been observed, such as in the eye and semen. Despite the importance of reintroduction of Ebola from this route, such events are rare in the population, which makes studying medical interventions to clear persistent virus difficult. We studied various doses of Ebola in ferrets and detected virus in the eyes of most ferrets. We believe this model will enable the study of medical interventions that promote clearance of Ebola virus from sites that promote persistence.


Subject(s)
Ebolavirus/genetics , Evolution, Molecular , Eye/virology , Hemorrhagic Fever, Ebola/physiopathology , Hemorrhagic Fever, Ebola/virology , Animals , Antibodies, Viral/immunology , Disease Models, Animal , Ebolavirus/immunology , Female , Ferrets/immunology , Hemorrhagic Fever, Ebola/immunology , Male , RNA, Viral/genetics
8.
NPJ Vaccines ; 6(1): 83, 2021 Jun 17.
Article in English | MEDLINE | ID: mdl-34140522

ABSTRACT

An array of SARS-CoV-2 virus variants have been isolated, propagated and used in in vitro assays, in vivo animal studies and human clinical trials. Observations of working stocks of SARS-CoV-2 suggest that sequential propagation in Vero cells leads to critical changes in the region of the furin cleavage site, which significantly reduce the value of the working stock for critical research studies. Serially propagating SARS-CoV-2 in Vero E6 cells leads to rapid increases in genetic variants while propagation in other cell lines (e.g. Vero/hSLAM) appears to mitigate this risk thereby improving the overall genetic stability of working stocks. From these observations, investigators are urged to monitor genetic variants carefully when propagating SARS-CoV-2 in Vero cells.

9.
J Virol Methods ; 290: 114087, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33515663

ABSTRACT

The development of safe diagnostic protocols for working with SARS-CoV-2 clinical samples at Biosafety Level 2 (BSL2) requires understanding of the effect of heat-treatment on SARS-CoV-2 viability and downstream RT-PCR sensitivity. In this study heating SARS-CoV-2/England/2/2020 to 56 °C and 60 °C for 15, 30 and 60 min reduced the virus titre by between 2.1 and 4.9 log10 pfu/mL (as determined by plaque assay). Complete inactivation did not occur and there was significant variability between replicates. Viable virus was detected by plaque assay after heat-treatment at 80 °C for 15 or 30 min but not 60 or 90 min. After heat-treatment at 80 °C for 60 min infectious virus was only detected by more sensitive virus culture. No viable virus was detected after heating to 80 °C for 90 min or 95 °C for 1 or 5 min. RT-PCR sensitivity was not compromised by heating to 56 °C and 60 °C. However, RT-PCR sensitivity was reduced (≥3 Ct value increase) after heating the virus to 80 °C for 30 min or longer, or 95 °C for 1 or 5 min. In summary we found that the efficacy of heat-inactivation varies greatly depending on temperature and duration. Local validation of heat-inactivation and its effects downstream is therefore essential for molecular testing.


Subject(s)
SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Virus Inactivation , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , Hot Temperature , Humans , Sensitivity and Specificity , Time Factors
10.
Lancet Infect Dis ; 21(4): 507-516, 2021 04.
Article in English | MEDLINE | ID: mdl-33065039

ABSTRACT

BACKGROUND: The 2013-16 Ebola virus disease epidemic in west Africa caused international alarm due to its rapid and extensive spread resulting in a significant death toll and social unrest within the affected region. The large number of cases provided an opportunity to study the long-term kinetics of Zaire ebolavirus-specific immune response of survivors in addition to known contacts of those infected with the virus. METHODS: In this observational cohort study, we worked with leaders of Ebola virus disease survivor associations in two regions of Guinea, Guéckédou and Coyah, to recruit survivors of Ebola virus disease, contacts from households of individuals known to have had Ebola virus disease, and individuals who were not knowingly associated with infected individuals or had not had Ebola virus disease symptoms to serve as negative controls. We did Zaire ebolavirus glycoprotein-specific T cell analysis on peripheral blood mononuclear cells (PBMCs) on location in Guinea and transported plasma and PBMCs back to Europe for antibody quantification by ELISA, functional neutralising antibody analysis using live Zaire ebolavirus, and T cell phenotype studies. We report on the longitudinal cellular and humoral response among Ebola virus disease survivors and highlight potentially paucisymptomatic infection. FINDINGS: We recruited 117 survivors of Ebola virus disease, 66 contacts, and 23 negative controls. The mean neutralising antibody titre among the Ebola virus disease survivors 3-14 months after infection was 1/174 (95% CI 1/136-1/223). Individual results varied greatly from 1/10 to more than 1/1000 but were on average ten times greater than that induced after 1 month by single dose Ebola virus vaccines. Following reactivation with glycoprotein peptide, the mean T cell responses among 116 Ebola virus disease survivors as measured by ELISpot was 305 spot-forming units (95% CI 257-353). The dominant CD8+ polyfunctional T cell phenotype, as measured among 53 Ebola virus disease survivors, was interferon γ+, tumour necrosis factor+, interleukin-2-, and the mean response was 0·046% of total CD8+ T cells (95% CI 0·021-0·071). Additionally, both neutralising antibody and T cell responses were detected in six (9%) of 66 Ebola virus disease contacts. We also noted that four (3%) of 117 individuals with Ebola virus disease infections did not have circulating Ebola virus-specific antibodies 3 months after infection. INTERPRETATION: The continuous high titre of neutralising antibodies and increased T cell response might support the concept of long-term protective immunity in survivors. The existence of antibody and T cell responses in contacts of individuals with Ebola virus disease adds further evidence to the existence of sub-clinical Ebola virus infection. FUNDING: US Food & Drug Administration, Horizon 2020 EU EVIDENT, Wellcome, UK Department for International Development. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.


Subject(s)
Antibodies, Viral/blood , Ebolavirus/immunology , Hemorrhagic Fever, Ebola/immunology , Survivors/statistics & numerical data , T-Lymphocytes/immunology , Adolescent , Adult , Antibodies, Viral/immunology , Antibodies, Viral/isolation & purification , Child , Child, Preschool , Ebolavirus/pathogenicity , Epidemics , Female , Guinea/epidemiology , Hemorrhagic Fever, Ebola/blood , Hemorrhagic Fever, Ebola/transmission , Hemorrhagic Fever, Ebola/virology , Humans , Immunity, Cellular , Immunity, Humoral , Infant , Infant, Newborn , Longitudinal Studies , Male , Middle Aged , Time Factors , Young Adult
11.
Chem Sci ; 8(11): 7780-7797, 2017 Nov 01.
Article in English | MEDLINE | ID: mdl-29163915

ABSTRACT

The West African Ebola virus outbreak underlined the importance of delivering mass diagnostic capability outside the clinical or primary care setting in effectively containing public health emergencies caused by infectious disease. Yet, to date, there is no solution for reliably deploying at the point of need the gold standard diagnostic method, real time quantitative reverse transcription polymerase chain reaction (RT-qPCR), in a laboratory infrastructure-free manner. In this proof of principle work, we demonstrate direct performance of RT-qPCR on fresh blood using far-red fluorophores to resolve fluorogenic signal inhibition and controlled, rapid freeze/thawing to achieve viral genome extraction in a single reaction chamber assay. The resulting process is entirely free of manual or automated sample pre-processing, requires no microfluidics or magnetic/mechanical sample handling and thus utilizes low cost consumables. This enables a fast, laboratory infrastructure-free, minimal risk and simple standard operating procedure suited to frontline, field use. Developing this novel approach on recombinant bacteriophage and recombinant human immunodeficiency virus (HIV; Lentivirus), we demonstrate clinical utility in symptomatic EBOV patient screening using live, infectious Filoviruses and surrogate patient samples. Moreover, we evidence assay co-linearity independent of viral particle structure that may enable viral load quantification through pre-calibration, with no loss of specificity across an 8 log-linear maximum dynamic range. The resulting quantitative rapid identification (QuRapID) molecular diagnostic platform, openly accessible for assay development, meets the requirements of resource-limited countries and provides a fast response solution for mass public health screening against emerging biosecurity threats.

12.
Sci Total Environ ; 554-555: 42-52, 2016 Jun 01.
Article in English | MEDLINE | ID: mdl-26950618

ABSTRACT

Organic compounds used in agriculture, industry, and households make their way into surface waters through runoff, leaking septic-conveyance systems, regulated and unregulated discharges, and combined sewer overflows, among other sources. Concentrations of these organic waste compounds (OWCs) in some Great Lakes tributaries indicate a high potential for adverse impacts on aquatic organisms. During 2010-13, 709 water samples were collected at 57 tributaries, together representing approximately 41% of the total inflow to the lakes. Samples were collected during runoff and low-flow conditions and analyzed for 69 OWCs, including herbicides, insecticides, polycyclic aromatic hydrocarbons, plasticizers, antioxidants, detergent metabolites, fire retardants, non-prescription human drugs, flavors/fragrances, and dyes. Urban-related land cover characteristics were the most important explanatory variables of concentrations of many OWCs. Compared to samples from nonurban watersheds (<15% urban land cover) samples from urban watersheds (>15% urban land cover) had nearly four times the number of detected compounds and four times the total sample concentration, on average. Concentration differences between runoff and low-flow conditions were not observed, but seasonal differences were observed in atrazine, metolachlor, DEET, and HHCB concentrations. Water quality benchmarks for individual OWCs were exceeded at 20 sites, and at 7 sites benchmarks were exceeded by a factor of 10 or more. The compounds with the most frequent water quality benchmark exceedances were the PAHs benzo[a]pyrene, pyrene, fluoranthene, and anthracene, the detergent metabolite 4-nonylphenol, and the herbicide atrazine. Computed estradiol equivalency quotients (EEQs) using only nonsteroidal endocrine-active compounds indicated medium to high risk of estrogenic effects (intersex or vitellogenin induction) at 10 sites. EEQs at 3 sites were comparable to values reported in effluent. This multifaceted study is the largest, most comprehensive assessment of the occurrence and potential effects of OWCs in the Great Lakes Basin to date.


Subject(s)
Environmental Monitoring , Organic Chemicals/analysis , Water Pollutants, Chemical/analysis , Geologic Sediments/chemistry , Great Lakes Region , Lakes , Organic Chemicals/toxicity , Phenols/analysis , Polycyclic Aromatic Hydrocarbons/analysis , Water Pollutants, Chemical/toxicity
13.
Biodivers Data J ; (2): e1125, 2014.
Article in English | MEDLINE | ID: mdl-25057255

ABSTRACT

BACKGROUND: Recent years have seen a surge in projects that produce large volumes of structured, machine-readable biodiversity data. To make these data amenable to processing by generic, open source "data enrichment" workflows, they are increasingly being represented in a variety of standards-compliant interchange formats. Here, we report on an initiative in which software developers and taxonomists came together to address the challenges and highlight the opportunities in the enrichment of such biodiversity data by engaging in intensive, collaborative software development: The Biodiversity Data Enrichment Hackathon. RESULTS: The hackathon brought together 37 participants (including developers and taxonomists, i.e. scientific professionals that gather, identify, name and classify species) from 10 countries: Belgium, Bulgaria, Canada, Finland, Germany, Italy, the Netherlands, New Zealand, the UK, and the US. The participants brought expertise in processing structured data, text mining, development of ontologies, digital identification keys, geographic information systems, niche modeling, natural language processing, provenance annotation, semantic integration, taxonomic name resolution, web service interfaces, workflow tools and visualisation. Most use cases and exemplar data were provided by taxonomists. One goal of the meeting was to facilitate re-use and enhancement of biodiversity knowledge by a broad range of stakeholders, such as taxonomists, systematists, ecologists, niche modelers, informaticians and ontologists. The suggested use cases resulted in nine breakout groups addressing three main themes: i) mobilising heritage biodiversity knowledge; ii) formalising and linking concepts; and iii) addressing interoperability between service platforms. Another goal was to further foster a community of experts in biodiversity informatics and to build human links between research projects and institutions, in response to recent calls to further such integration in this research domain. CONCLUSIONS: Beyond deriving prototype solutions for each use case, areas of inadequacy were discussed and are being pursued further. It was striking how many possible applications for biodiversity data there were and how quickly solutions could be put together when the normal constraints to collaboration were broken down for a week. Conversely, mobilising biodiversity knowledge from their silos in heritage literature and natural history collections will continue to require formalisation of the concepts (and the links between them) that define the research domain, as well as increased interoperability between the software platforms that operate on these concepts.

14.
Environ Sci Technol ; 44(20): 7956-63, 2010 Oct 15.
Article in English | MEDLINE | ID: mdl-20822128

ABSTRACT

This study investigated the source, transport, and occurrence of human enteric viruses in municipal well water, focusing on sanitary sewer sources. A total of 33 wells from 14 communities were sampled once for wastewater tracers and viruses. Wastewater tracers were detected in four of these wells, and five wells were virus- positive by qRT-PCR. These results, along with exclusion of wells with surface water sources, were used to select three wells for additional investigation. Viruses and wastewater tracers were found in the groundwater at all sites. Some wastewater tracers, such as ionic detergents, flame retardants, and cholesterol, were considered unambiguous evidence of wastewater. Sampling at any given time may not show concurrent virus and tracer presence; however, given sufficient sampling over time, a relation between wastewater tracers and virus occurrence was identified. Presence of infectious viruses at the wellhead demonstrates that high-capacity pumping induced sufficiently short travel times for the transport of infectious viruses. Therefore, drinking-water wells are vulnerable to contaminants that travel along fast groundwater flowpaths even if they contribute a small amount of virus-laden water to the well. These results suggest that vulnerability assessments require characterization of "low yield-fast transport" in addition to traditional "high yield-slow transport", pathways.


Subject(s)
Enterovirus/isolation & purification , Sewage , Water Microbiology , Water Supply , Humans , Reverse Transcriptase Polymerase Chain Reaction
15.
Environ Sci Technol ; 44(19): 7376-82, 2010 Oct 01.
Article in English | MEDLINE | ID: mdl-20806974

ABSTRACT

A new perspective on the severity of aquatic toxicity impact of road salt was gained by a focused research effort directed at winter runoff periods. Dramatic impacts were observed on local, regional, and national scales. Locally, samples from 7 of 13 Milwaukee, Wisconsin area streams exhibited toxicity in Ceriodaphnia dubia and Pimephales promelas bioassays during road-salt runoff. Another Milwaukee stream was sampled from 1996 to 2008 with 72% of 37 samples exhibiting toxicity in chronic bioassays and 43% in acute bioassays. The maximum chloride concentration was 7730 mg/L. Regionally, in southeast Wisconsin, continuous specific conductance was monitored as a chloride surrogate in 11 watersheds with urban land use from 6.0 to 100%. Elevated specific conductance was observed between November and April at all sites, with continuing effects between May and October at sites with the highest specific conductance. Specific conductance was measured as high as 30,800 µS/cm (Cl = 11,200 mg/L). Chloride concentrations exceeded U.S. Environmental Protection Agency (USEPA) acute (860 mg/L) and chronic (230 mg/L) water-quality criteria at 55 and 100% of monitored sites, respectively. Nationally, U.S. Geological Survey historical data were examined for 13 northern and 4 southern metropolitan areas. Chloride concentrations exceeded USEPA water-quality criteria at 55% (chronic) and 25% (acute) of the 168 monitoring locations in northern metropolitan areas from November to April. Only 16% (chronic) and 1% (acute) of sites exceeded criteria from May to October. At southern sites, very few samples exceeded chronic water-quality criteria, and no samples exceeded acute criteria.


Subject(s)
Cyprinidae , Daphnia/drug effects , Sodium Chloride/toxicity , Water/standards , Animals , Sodium Chloride/chemistry , Wisconsin
16.
Biotechnol Appl Biochem ; 56(3): 85-93, 2010 Jun 21.
Article in English | MEDLINE | ID: mdl-20441568

ABSTRACT

Secretory and membrane-bound proteins are generally produced in lower amounts in insect cells compared with cytoplasmic and nuclear proteins. There may be many reasons for this, including degradation of recombinant proteins by proteases, competition for cellular resources between native and recombinant proteins, and physical blockage of the secretory pathways. In the present study, we describe the construction of a baculovirus in which chiA (chitinase) and cath (cathepsin) genes have been deleted and show improved recombinant protein expression using this vector. We confirmed the complete removal of both genes by PCR, restriction enzyme analysis and enzyme assays, and the modified virus DNA was shown to be stable in bacterial cells over multiple passages. A selection of recombinant genes were inserted into the double-deletion virus and their expression levels compared with recombinant viruses that had single or no gene deletions. In all instances, the double-deletion viruses showed greatly enhanced levels of protein production for both secreted and nuclear/cytoplasmic proteins. In summary, we have conclusively demonstrated the importance of this deletion vector for the high-level production of recombinant proteins.


Subject(s)
Baculoviridae/genetics , Membrane Proteins/biosynthesis , Protein Engineering/methods , Recombinant Proteins/biosynthesis , Animals , Baculoviridae/enzymology , Cathepsins/genetics , Cells, Cultured , Chitinases/genetics , Gene Deletion , Gene Expression , Humans , Insecta/cytology , Membrane Proteins/genetics
17.
Biotechnol Bioeng ; 101(6): 1115-22, 2008 Dec 15.
Article in English | MEDLINE | ID: mdl-18781697

ABSTRACT

The baculovirus expression system is one of the most popular methods used for the production of recombinant proteins but has several complex steps which have proved inherently difficult to adapt to a multi-parallel process. We have developed a bacmid vector that does not require any form of selection pressure to separate recombinant virus from non-recombinant parental virus. The method relies on homologous recombination in insect cells between a transfer vector containing a gene to be expressed and a replication-deficient bacmid. The target gene replaces a bacterial replicon at the polyhedrin loci, simultaneously restoring a virus gene essential for replication. Therefore, only recombinant virus can replicate facilitating the rapid production of multiple recombinant viruses on automated platforms in a one-step procedure. Using this vector allowed us to automate the generation of multiple recombinant viruses with a robotic liquid handler and then rapidly screen infected insect cell supernatant for the presence of secreted proteins.


Subject(s)
Baculoviridae/genetics , Biotechnology/methods , Genetic Vectors , Recombinant Proteins/genetics , Animals , Cell Line , Cloning, Molecular , Gene Expression , Insecta , Molecular Biology/methods , Recombination, Genetic , Virus Replication
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