Microscopic slide flocculation and macroscopic tube flocculation tests for pullorum disease and a comparison of them with the tube agglutination test

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A Structure-Function Analysis of the φX174 DNA Piloting Protein

In order to initiate an infection, bacteriophages must deliver their large, hydrophilic genomes across their host’s hydrophobic cell wall. Bacteriophage φX174 accomplishes this task with a set of identical DNA piloting proteins. The structure of the piloting protein’s central domain was solved to 2.4 Å resolution. In it, ten proteins are oligomerized into an α-helical barrel, or tube, that is long enough to span the host’s cell wall and wide enough for the circular, ssDNA to pass through. This structure was used as a guide to explore the mechanics of φX174 genome delivery. In the first study, the H-tube’s highly repetitive primary and quaternary structure made it amenable to a genetic analysis using in-frame insertions and deletions. Length-altered proteins were characterized for the ability to perform the protein’s three known functions: participation in particle assembly, genome translocation, and stimulation of viral protein synthesis. The tube’s inner surface was altered in the second study. The surface is primarily lined with amide and guanidinium containing amino acid side chains with the exception of four sites near the tube’s C-terminal end. The four sites are conserved across microvirus clades, suggesting that they may play an important role during genome delivery. To test this hypothesis and explore the general role of the amide and guanidinium containing side chains, the amino acids at these sites were changed to glutamine. The resulting mutants had a cold-sensitive phenotype at 22°C. Viral lifecycle steps were assayed in order to determine which step was disrupted by the mutant glutamine residues. The results support a model in which a balance of forces governs genome delivery: potential energy provided by the densely packaged viral genome and/or an osmotic gradient push the genome into the cell, while the tube’s inward facing residues exert a frictional force on the genome as it passes. Bacteriophage must first identify a susceptible host prior to genome delivery. In the final study, biochemical and genetic analyses were conducted with two closely related bacteriophages, α3 and ST-1. Despite ~90% amino acid identity, the natural host of α3 is Escherichia coli C, whereas ST-1 is a K-12-specific phage. To determine which structural proteins conferred host range specificity, chimeric virions were generated by individually interchanging the coat, spike, or DNA pilot proteins. Interchanging the coat protein switched host range. However, host range expansion could be conferred by single point mutations in the coat protein. The expansion phenotype was recessive: mutant progeny from co-infected cells did not display the phenotype. Novel virus propagation and selection protocols were developed to isolate host range expansion mutants. The resulting genetic and structural data were consistent enough that host range expansion could be predicted, broadening the classical definition of antireceptors to include interfaces between protein complexes within the capsid

Fragmenting the Landscape

My paintings are done from my memory of nature experienced at different moments in time and place in Canada and Europe, discovered during my frequent travels. Colour, light, movement, smell and sound recalled in memory, lead to abstract formulations in which an expressive softness is mixed with harsh reality

The External Validity of Psychometric Testing Methods and Their Meaning for Safe Road Performance

The aim of the paper is to investigate which psychometric tools commonly used by Polish transport psychologists appropriately measure necessary abilities of professional drivers. According to Levis-Evans’ differentiation between the driver ’s performance and the driver’s behavior, we explored a statistical relation between the results of tests currently used by transport psychologists, measured according to Szalma’s individual differences and safe behaviors on roads. We examine validity of tests using data based on real professional drivers’ behavior. The sample included 200 drivers involved in accidents and collisions, and 100 who behaved safely. We tested external validity of chosen psychometric tools by analyzing statistically the relation between test scores and unsafe driving behavior recorded by the police. The results show that only few measurements are valid for differentiation of safe and unsafe drivers. The paper indicates the methodology to reach the prognostic value of the diagnostic tests employed by transport psychologist

Variations in the NBN/NBS1 gene and the risk of breast cancer in non-BRCA1/2 French Canadian families with high risk of breast cancer

<p>Abstract</p> <p>Background</p> <p>The Nijmegen Breakage Syndrome is a chromosomal instability disorder characterized by microcephaly, growth retardation, immunodeficiency, and increased frequency of cancers. Familial studies on relatives of these patients indicated that they also appear to be at increased risk of cancer.</p> <p>Methods</p> <p>In a candidate gene study aiming at identifying genetic determinants of breast cancer susceptibility, we undertook the full sequencing of the <it>NBN </it>gene in our cohort of 97 high-risk non-<it>BRCA1 </it>and -<it>BRCA2 </it>breast cancer families, along with 74 healthy unrelated controls, also from the French Canadian population. <it>In silico </it>programs (ESEfinder, NNSplice, Splice Site Finder and MatInspector) were used to assess the putative impact of the variants identified. The effect of the promoter variant was further studied by luciferase gene reporter assay in MCF-7, HEK293, HeLa and LNCaP cell lines.</p> <p>Results</p> <p>Twenty-four variants were identified in our case series and their frequency was further evaluated in healthy controls. The potentially deleterious p.Ile171Val variant was observed in one case only. The p.Arg215Trp variant, suggested to impair NBN binding to histone γ-H2AX, was observed in one breast cancer case and one healthy control. A promoter variant c.-242-110delAGTA displayed a significant variation in frequency between both sample sets. Luciferase reporter gene assay of the promoter construct bearing this variant did not suggest a variation of expression in the MCF-7 breast cancer cell line, but indicated a reduction of luciferase expression in both the HEK293 and LNCaP cell lines.</p> <p>Conclusion</p> <p>Our analysis of <it>NBN </it>sequence variations indicated that potential <it>NBN </it>alterations are present, albeit at a low frequency, in our cohort of high-risk breast cancer cases. Further analyses will be needed to fully ascertain the exact impact of those variants on breast cancer susceptibility, in particular for variants located in <it>NBN </it>promoter region.</p

Cognitive and Tactile Factors Affecting Human Haptic Performance in Later Life

Background: Vision and haptics are the key modalities by which humans perceive objects and interact with their environment in a target-oriented manner. Both modalities share higher-order neural resources and the mechanisms required for object exploration. Compared to vision, the understanding of haptic information processing is still rudimentary. Although it is known that haptic performance, similar to many other skills, decreases in old age, the underlying mechanisms are not clear. It is yet to be determined to what extent this decrease is related to the age-related loss of tactile acuity or cognitive capacity. Methodology/Principal Findings: We investigated the haptic performance of 81 older adults by means of a cross-modal object recognition test. Additionally, we assessed the subjects ’ tactile acuity with an apparatus-based two-point discrimination paradigm, and their cognitive performance by means of the non-verbal Raven-Standard-Progressive matrices test. As expected, there was a significant age-related decline in performance on all 3 tests. With the exception of tactile acuity, this decline was found to be more distinct in female subjects. Correlation analyses revealed a strong relationship between haptic and cognitive performance for all subjects. Tactile performance, on the contrary, was only significantly correlated with male subjects ’ haptic performance. Conclusions: Haptic object recognition is a demanding task in old age, especially when it comes to the exploration o

Conceptualizing and measuring strategy implementation – a multi-dimensional view

Through quantitative methodological approaches for studying the strategic management and planning process, analysis of data from 208 senior managers involved in strategy processes within ten UK industrial sectors provides evidence on the measurement properties of a multi-dimensional instrument that assesses ten dimensions of strategy implementation. Using exploratory factor analysis, results indicate the sub-constructs (the ten dimensions) are uni-dimensional factors with acceptable reliability and validity; whilst using three additional measures, and correlation and hierarchical regression analysis, the nomological validity for the multi-dimensional strategy implementation construct was established. Relative importance of ten strategy implementation dimensions (activities) for practicing managers is highlighted, with the mutually and combinative effects drawing conclusion that senior management involvement leads the way among the ten key identified activities vital for successful strategy implementation

A Structure-Function Analysis of the ΦX174 DNA Piloting Protein

In order to initiate an infection, bacteriophages must deliver their large, hydrophilic genomes across their host’s hydrophobic cell wall. Bacteriophage ϕX174 accomplishes this task with a set of identical DNA piloting proteins. The structure of the piloting protein’s central domain was solved to 2.4 Å resolution. In it, ten proteins are oligomerized into an α-helical barrel, or tube, that is long enough to span the host’s cell wall and wide enough for the circular, ssDNA to pass through. This structure was used as a guide to explore the mechanics of ϕX174 genome delivery. In the first study, the H-tube’s highly repetitive primary and quaternary structure made it amenable to a genetic analysis using in-frame insertions and deletions. Length-altered proteins were characterized for the ability to perform the protein’s three known functions: participation in particle assembly, genome translocation, and stimulation of viral protein synthesis. The tube’s inner surface was altered in the second study. The surface is primarily lined with amide and guanidinium containing amino acid side chains with the exception of four sites near the tube’s C-terminal end. The four sites are conserved across microvirus clades, suggesting that they may play an important role during genome delivery. To test this hypothesis and explore the general role of the amide and guanidinium containing side chains, the amino acids at these sites were changed to glutamine. The resulting mutants had a cold-sensitive phenotype at 22 °C. Viral lifecycle steps were assayed in order to determine which step was disrupted by the mutant glutamine residues. The results support a model in which a balance of forces governs genome delivery: potential energy provided by the densely packaged viral genome and/or an osmotic gradient push the genome into the cell, while the tube’s inward facing residues exert a frictional force on the genome as it passes. Bacteriophage must first identify a susceptible host prior to genome delivery. In the final study, biochemical and genetic analyses were conducted with two closely related bacteriophages, α3 and ST-1. Despite ~90% amino acid identity, the natural host of α3 is Escherichia coli C, whereas ST-1 is a K-12-specific phage. To determine which structural proteins conferred host range specificity, chimeric virions were generated by individually interchanging the coat, spike, or DNA pilot proteins. Interchanging the coat protein switched host range. However, host range expansion could be conferred by single point mutations in the coat protein. The expansion phenotype was recessive: mutant progeny from co-infected cells did not display the phenotype. Novel virus propagation and selection protocols were developed to isolate host range expansion mutants. The resulting genetic and structural data were consistent enough that host range expansion could be predicted, broadening the classical definition of antireceptors to include interfaces between protein complexes within the capsid