Education and Ethnic Minorities: The Political, Institutional and Professional Responses in the United Kingdom

The thesis starts with an account of the post-war changes in the ethnic composition of the British population including an estimation of the racial and ethnic mix of the school classroom. Basic terms such as "race", ethnicity and culture are defined and the concepts of a multi-racial, multi-ethnic and multi-cultural society are considered. The ideologies of assimilation, integration and cultural pluralism, and their relevance to the British educational system, are examined. A specific analysis of the political and institutional responses to the educational "needs" of ethnic minority children is conducted against the background of a dominant ideology of "assimilation" in the nineteen sixties and early seventies. These responses are further discussed for the period from the late nineteen seventies to the mid nineteen eighties, an era characterised by a shift of emphasis from assimilation towards ethnic diversity and cultural pluralism. The implications of these changes for the education of children from ethnic minority groups are considered. The second part of the thesis is concerned with the issue of academic achievement and assesses theories connected with the debate over "heredity versus environment" and their consequences for "racial" differences and measured intelligence. The significance of a variety of other factors such as language, identity and teachers' expectations is also discussed. Different conceptions of multi-cultural education are considered with an analysis of the factors related to the origins and initiation of such policies in British schools. The major criticisms of multi-cultural education are stated and their implications for the implementation of multi-ethnic educational policies are examined. The final section of the thesis describes the development of multi-cultural education in an Inner London school during the period 1978-86. With the use of both participant observation and survey analysis the response of teachers to multi-cultural education initiatives is presented. The finding of the survey on teachers' attitudes are analysed in connection with the definitions, objectives and the implementation of multi-cultural education

Engineering and crystal structure of a monomeric FLT3 ligand variant

The overarching paradigm for the activation of class III and V receptor tyrosine kinases (RTKs) prescribes cytokine-mediated dimerization of the receptor ectodomains and homotypic receptor-receptor interactions. However, structural studies have shown that the hematopoietic receptor FLT3, a class III RTK, does not appear to engage in such receptor-receptor contacts, despite its efficient dimerization by dimeric FLT3 ligand (FL). As part of efforts to better understand the intricacies of FLT3 activation, we sought to engineer a monomeric FL. It was found that a Leu27Asp substitution at the dimer interface of the cytokine led to a stable monomeric cytokine (FLL27D) without abrogation of receptor binding. The crystal structure of FLL27D at 1.65 angstrom resolution revealed that the introduced point mutation led to shielding of the hydrophobic footprint of the dimerization interface in wild-type FL without affecting the conformation of the FLT3 binding site. Thus, FLL27D can serve as a monomeric FL variant to further interrogate the assembly mechanism of extracellular complexes of FLT3 in physiology and disease

The bacterial antitoxin HipB establishes a ternary complex with operator DNA and phosphorylated toxin HipA to regulate bacterial persistence

Nearly all bacteria exhibit a type of phenotypic growth described as persistence that is thought to underlie antibiotic tolerance and recalcitrant chronic infections. The chromosomally encoded high-persistence (Hip) toxin-antitoxin proteins HipA(SO) and HipB(SO) from Shewanella oneidensis, a proteobacterium with unusual respiratory capacities, constitute a type II toxin-antitoxin protein module. Here we show that phosphorylated HipA(SO) can engage in an unexpected ternary complex with HipB(SO) and double-stranded operator DNA that is distinct from the prototypical counterpart complex from Escherichia coli. The structure of HipB(SO) in complex with operator DNA reveals a flexible C-terminus that is sequestered by HipA(SO) in the ternary complex, indicative of its role in binding HipA(SO) to abolish its function in persistence. The structure of HipA(SO) in complex with a non-hydrolyzable ATP analogue shows that HipA(SO) autophosphorylation is coupled to an unusual conformational change of its phosphorylation loop. However, HipA(SO) is unable to phosphorylate the translation factor Elongation factor Tu, contrary to previous reports, but in agreement with more recent findings. Our studies suggest that the phosphorylation state of HipA is an important factor in persistence and that the structural and mechanistic diversity of HipAB modules as regulatory factors in bacterial persistence is broader than previously thought

Delineation of the Pasteurellaceae-specific GbpA-family of glutathione-binding proteins

<p>Abstract</p> <p>Background</p> <p>The Gram-negative bacterium <it>Haemophilus influenzae </it>is a glutathione auxotroph and acquires the redox-active tripeptide by import. The dedicated glutathione transporter belongs to the ATP-binding cassette (ABC)-transporter superfamily and displays more than 60% overall sequence identity with the well-studied dipeptide (Dpp) permease of <it>Escherichia coli</it>. The solute binding protein (SBP) that mediates glutathione transport in <it>H. influenzae </it>is a lipoprotein termed GbpA and is 54% identical to <it>E. coli </it>DppA, a well-studied member of family 5 SBP's. The discovery linking GbpA to glutathione import came rather unexpectedly as this import-priming SBP was previously annotated as a heme-binding protein (HbpA), and was thought to mediate heme acquisition. Nonetheless, although many SBP's have been implicated in more than one function, a prominent physiological role for GbpA and its partner permease in heme acquisition appears to be very unlikely. Here, we sought to characterize five representative GbpA homologs in an effort to delineate the novel GbpA-family of glutathione-specific family 5 SBPs and to further clarify their functional role in terms of ligand preferences.</p> <p>Results</p> <p>Lipoprotein and non-lipoprotein GbpA homologs were expressed in soluble form and substrate specificity was evaluated via a number of ligand binding assays. A physiologically insignificant affinity for hemin was observed for all five GbpA homologous test proteins. Three out of five test proteins were found to bind glutathione and some of its physiologically relevant derivatives with low- or submicromolar affinity. None of the tested SBP family 5 allocrites interacted with the remaining two GbpA test proteins. Structure-based sequence alignments and phylogenetic analysis show that the two binding-inert GbpA homologs clearly form a separate phylogenetic cluster. To elucidate a structure-function rationale for this phylogenetic differentiation, we determined the crystal structure of one of the GbpA family outliers from <it>H. parasuis</it>. Comparisons thereof with the previously determined structure of GbpA in complex with oxidized glutathione reveals the structural basis for the lack of allocrite binding capacity, thereby explaining the outlier behavior.</p> <p>Conclusions</p> <p>Taken together, our studies provide for the first time a collective functional look on a novel, <it>Pasteurellaceae</it>-specific, SBP subfamily of glutathione binding proteins, which we now term GbpA proteins. Our studies strongly implicate GbpA family SBPs in the priming step of ABC-transporter-mediated translocation of useful forms of glutathione across the inner membrane, and rule out a general role for GbpA proteins in heme acquisition.</p

Structure and oligomerization of the periplasmic domain of GspL from the type II secretion system of Pseudomonas aeruginosa

The ability of bacteria to infect a host relies in part on the secretion of molecular virulence factors across the cell envelope.Pseudomonas aeruginosa, a ubiquitous environmental bacterium causing opportunistic infections in humans, employs the type II secretion system (T2SS) to transport effector proteins across its cellular envelope as part of a diverse array of virulence strategies.General secretory pathway protein L (GspL) is an essential inner-membrane component of the T2SS apparatus, and is thought to facilitate transduction of the energy from ATP hydrolysis in the cytoplasm to the periplasmic components of the system.However,our incomplete understanding of the assembly principles of the T2SS machinery prevents the mechanistic deconvolution of T2SS-mediated protein secretion.Here we show via two crystal structures that the periplasmic ferredoxin-like domain of GspL (GspL(fld)) is a dimer stabilized by hydrophobic interactions, and that this interface may allow significant interdomain plasticity.The general dimerization mode of GspL(fld) is shared with GspL from Vibrio parahaemolyticus suggesting a conserved oligomerization mode across the GspL family. Furthermore, we identified a tetrameric form of the complete periplasmic segment of GspL (GspL(Peri)) which indicates that GspL may be able to adopt multiple oligomeric states as part of its dynamic role in the T2SS apparatus

Secure Data Communication in Autonomous V2X Systems

In Vehicle-to-Everything (V2X) communication systems, vehicles as well as infrastructure devices can interact and exchange data with each other. This capability is used to implement intelligent transportation systems applications. Data confidentiality and integrity need to be preserved in unverified and untrusted environments. In this paper, we propose a solution that provides (a) role-based and attribute-based access control to encrypted data and (b) encrypted search over encrypted data. Vehicle Records contain sensitive information about the owners and vehicles in encrypted form with attached access control policies and policy enforcement engine. Our solution supports decentralized and distributed data exchange, which is essential in V2X systems, where a Central Authority is not required to enforce access control policies. Furthermore, we facilitate querying encrypted Vehicle Records through Structured Query Language (SQL) queries. Vehicle Records are stored in a database in untrusted V2X cloud environment that is prone to provide the attackers with a large attack surface. Big datasets, stored in cloud, can be used for data analysis, such as traffic pattern analysis. Our solution protects sensitive vehicle and owner information from curious or malicious information cloud administrators. Support of indexing improves performance of queries that are forwarded to relevant encrypted Vehicle Records, which are stored in the cloud. We measure the performance overhead of our security solution based on self-protecting Vehicle Records with encrypted search capabilities in V2X communication systems and analyze the effect of security over safety

Development and application of a screening assay for glycoside phosphorylases

A

Towards structural studies of the old yellow enzyme homologue SYE4 from Shewanella oneidensis and its complexes at atomic resolution

Shewanella oneidensis is an environmentally versatile Gram-negative gamma-proteo-bacterium that is endowed with an unusually large proteome of redox proteins. Of the four old yellow enzyme (OYE) homologues found in S. oneidensis, SYE4 is the homologue most implicated in resistance to oxidative stress. SYE4 was recombinantly expressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1) and were moderately pseudo-merohedrally twinned, emulating a P422 metric symmetry. The native crystals of SYE4 were of exceptional diffraction quality and provided complete data to 1.10 angstrom resolution using synchrotron radiation, while crystals of the reduced enzyme and of the enzyme in complex with a wide range of ligands typically led to high-quality complete data sets to 1.30-1.60 angstrom resolution, thus providing a rare opportunity to dissect the structure-function relationships of a good-sized enzyme (40 kDa) at true atomic resolution. Here, the attainment of a number of experimental milestones in the crystallographic studies of SYE4 and its complexes are reported, including isolation of the elusive hydride-Meisenheimer complex