Single-chain antibodies produced by phage display against the C-terminal 19 kDa region of merozoite surface protein-1of Plasinodium yoelii reduce parasite growth following challenge

Antibodies have the potential to be therapeutic reagents for malaria. Here we describe the production of a novel phage antibody display library against the C-terminal 19 kDa region of the Plasmodium yoelii YM merozoite surface protein-1 (MSP1(19)). In vivo studies against homologous lethal malaria challenge show an anti-parasite effect in a dose dependent manner, and analysis by plasmon resonance indicates binding to the antigen is comparable to the binding of a protective monoclonal antibody. The data support the lack of a need for any antibody Fc-related function and hold great significance for the development of a therapeutic reagent for malaria. (C) 2002 Elsevier Science Ltd. All rights reserved.

Analysis of toxin profiles in three different fish species causing ciguatera fish poisoning in Guadeloupe, French West Indies

A grey snapper (Lutjanus griseus), a grouper (Serranidae) and a blackjack (Caranx lugubris) were implicated in three different ciguatera poisonings in Guadeloupe, French West Indies. A mouse bioassay indicated toxicity for each specimens: 0.5-1, greater than or equal to 1 and > 1 M Ug g(-1), respectively. After purification by gel filtration chromatography, the samples were analysed by high-performance liquid chromatography coupled to mass spectrometry (LC-MS). The toxin profiles differ from one fish to another. C-CTX-1 was detected at 0.24, 0.90 and 13.8 ng g(-1) flesh in the snapper, grouper and jack, respectively. It contributed only to part of the whole toxicity determined by the mouse bioassay. Other toxins identified were C-CTX-2 (a C-CTX-1 epimer), three additional isomers of C-CTX-1 or -2, and five ciguatoxin congeners (C-CTX-1127, C-CTX-1143 and its isomer C-CTX-1143a, and C-CTX-1157 and its isomer C-CTX-1157b). Putative hydroxy-polyether-like compounds were also detected in the flesh of the grouper with [M+ + H](+) ions at m/z 851.51, 857.50, 875.51, 875.49 and 895.54 Da. Some of these compounds have the same mass range as some known dinoflagellate toxins. In conclusion, this study confirms the usefulness of LC-MS analysis to determine the ciguatoxins levels and the toxin profile in fish flesh hazardous to humans.

Antagonists of protein kinase C inhibit rat retinal glutamate transport activity in situ

Neuronal and glial high-affinity transporters regulate extracellular glutamate concentration, thereby terminating synaptic transmission and preventing neuronal excitotoxicity. Glutamate transporter activity has been shown to be modulated by protein kinase C (PKC) in cell culture. This is the first study to demonstrate such modulation in situ, by following the fate of the non-metabolisable glutamate transporter substrate, D-aspartate. In the rat retina, pan-isoform PKC inhibition with chelerythrine suppressed glutamate uptake by GLAST (glutamate/aspartate transporter), the dominant excitatory amino acid transporter localized to the glial Muller cells. This effect was mimicked by rottlerin but not by Go6976, suggesting the involvement of the PKCdelta isoform, but not PKCalpha, beta or gamma. Western blotting and immunohistochemical labeling revealed that the suppression of glutamate transport was not due to a change in transporter expression. Inhibition of PKCdelta selectively suppressed GLAST but not neuronal glutamate transporter activity. These data suggest that the targeting of specific glutamate transporters with isoform-specific modulators of PKC activity may have significant implications for the understanding of neurodegenerative conditions arising from compromised glutamate homeostasis, e.g. glaucoma and amyotrophic lateral sclerosis.

Locomotion at-1.0 degrees C: burst swimming performance of five species of Antarctic fish

We investigated the burst swimming performance of five species of Antarctic fish at -1.0degreesC. The species studied belonged to the suborder, Notothenioidei, and from the families, Nototheniidae and Bathydraconidae. Swimming performance of the fish was assessed over the initial 300 ms of a startle response using surgically attached miniature accelerometers. Escape responses in all fish consisted of a C-type fast start; consisting of an initial pronounced bending of the body into a C-shape, followed by one or more complete tail-beats and an un-powered glide. We found significant differences in the swimming performance of the five species of fish examined, with average maximum swimming velocities (U-max) ranging from 0.91 to 1.39 m s(-1) and maximum accelerations (A(max)) ranging from 10.6 to 15.6 m s(-2). The cryopelagic species, Pagothenia borchgrevinki, produced the fastest escape response, reaching a U-max and A(max) of 1.39 m s(-1) and 15.6 m s(-2), respectively. We also compared the body shapes of each fish species with their measures of maximum burst performance. The dragonfish, Gymnodraco acuticeps, from the family Bathdraconidae, did not conform to the pattern observed for the other four fish species belonging to the family Nototheniidae. However, we found a negative relationship between buoyancy of the fish species and burst swimming performance. (C) 2002 Elsevier Science Ltd. All rights reserved.

Variation in articulatory timing of three English consonants: An electropalatographic investigation

Increasingly, electropalatography (EPG) is being used in speech pathology research to identify and describe speech disorders of neurological origin. However, limited data currently exists that describes normal articulatory segment timing and the degree of variability exhibited by normal speakers when assessed with EPG. Therefore, the purpose of the current investigation was to use the Reading EPG3 system to quantify segmental timing values and examine articulatory timing variability for three English consonants. Ten normal subjects repeated ten repetitions of CV words containing the target consonants /t/, /l/, and /s/ while wearing an artificial palate. The target consonants were followed by the /i/ vowel and were contained in the carrier phrase 'I saw a __'. Mean duration of the approach, closure/constriction, and release phases of consonant articulation were calculated. In addition, inter-subject articulatory timing variability was investigated using descriptive graphs and intra-subject articulatory timing variability was investigated using a coefficient of variation. Results revealed the existence of intersubject variability for mean segment timing values. This could be attributed to individual differences in the suprasegmental features of speech and individual differences in oral cavity size and structure. No significant differences were reported for degree of intra-subject variability between the three sounds for these same phases of articulation. However, when this data set was collapsed, results revealed that the closure/constriction phase of consonant articulation exhibited significantly less intra-subject variability than both the approach and release phases. The stabilization of the tongue against the fixed structure of the hard palate during the closure phase of articulation may have reduced the levels of intra-subject variability.

C-terminal sequences in R-Ras are involved in integrin regulation and in plasma membrane microdomain distribution

The small GTPases R-Ras and H-Ras are highly homologous proteins with contrasting biological properties, for example, they differentially modulate integrin affinity: H-Ras suppresses integrin activation in fibroblasts whereas R-Ras can reverse this effect of H-Ras. To gain insight into the sequences directing this divergent phenotype, we investigated a panel of H-Ras/R-Ras chimeras and found that sequences in the R-Ras hypervariable C-terminal region including amino acids 175-203 are required for the R-Ras ability to increase integrin activation in CHO cells; however, the proline-rich site in this region, previously reported to bind the adaptor protein Nck, was not essential for this effect. In addition, we found that the GTPase TC21 behaved similarly to R-Ras. Because the C-termini of Ras proteins can control their subcellular localization, we compared the localization of H-Ras and R-Ras. In contrast to H-Ras, which migrates out of lipid rafts upon activation, we found that activated R-Ras remained localized to lipid rafts. However, functionally distinct H-Ras/R-Ras chimeras containing different C-terminal R-Ras segments localized to lipid rafts irrespective of their integrin phenotype. (C) 2003 Elsevier Inc. All rights reserved.

Broadening conceptions of curriculum for young people: Reports from three student-teachers on exchange

Research reports prepared by three Australian preservice teachers--Paula Shaw, Chris Sharp and Scott McDonald--undertaking their teacher education practicum in Canada, form the basis of this paper. The reports provide critical insights into three aspects of education for young people in both Canada and Australia. They also provide critical insight into the ways in which a practicum research project, along with the opportunities afforded through an international experience, enabled the preservice teachers to broaden their understanding of the curriculum for young people, of issues relevant to the diverse needs of young people, and of themselves and their priorities as teachers. The preservice teachers investigated three topics: attempts to reduce homophobia in schools; the presence or absence of Aboriginal content in the school curricula in British Columbia and Queensland; and "schools-within-schools" as a means to meet the needs of diverse student populations. Linda Farr Darling from the University of British Columbia provides a response to the three reports.

Factorizations of the complete graph into C-5-factors and 1-factors

In this paper, we show that K-10n can be factored into alpha C-5-factors and beta 1-factors for all non-negative integers alpha and beta satisfying 2alpha + beta = 10(n) - 1.

Stratigraphy, facies architecture and tectonic implications of the Upper Devonian to Lower Carboniferous Campwyn Volcanics of the northern New England Fold Belt

Upper Devonian to Lower Carboniferous strata of the Campwyn Volcanics of east central Queensland preserve a substantial sequence of first-cycle volcaniclastic sedimentary and coeval volcanic rocks that record prolonged volcanic activity along the northern New England Fold Belt. The style and scale of volcanism varied with time, producing an Upper Devonian sequence of mafic volcano-sedimentary rocks overlain by a rhyolitic ignimbrite-dominated sequence that passes upward into a Lower Carboniferous limestone-bearing sedimentary sequence. We define two facies associations for the Campwyn Volcanics. A lower facies association is dominated by mafic volcanic-derived sedimentary breccias with subordinate primary mafic volcanic rocks comprising predominantly hyaloclastite and peperite. Sedimentary breccias record episodic and high energy, subaqueous depositional events with clastic material sourced from a mafic lava-dominated terrain. Some breccias contain a high proportion of attenuated dense, glassy mafic juvenile clasts, suggesting a syn-eruptive origin. The lower facies association coarsens upwards from a lithic sand-dominated sequence through a thick interval of pebble- to boulder-grade polymict volcaniclastic breccias, culminating in facies that demonstrate subaerial exposure. The silicic upper facies association marks a significant change in eruptive style, magma composition and the nature of eruptive sources, as well as the widespread development of subaerial depositional conditions. Crystal-rich, high-grade, low- to high-silica rhyolite ignimbrites dominate the base of this facies association. Biostratigraphic age controls indicate that the ignimbrite-bearing sequences are Famennian to lower-mid Tournaisian in age. The ignimbrites represent extra-caldera facies with individual units up to 40 m thick and mostly lacking coarse lithic breccias. Thick deposits of pyroclastic material interbedded with fine-grained siliceous sandstone and mudstone (locally radiolarian-bearing) were deposited from pyroclastic flows that crossed palaeoshorelines or represent syn-eruptive, resedimented pyroclastic material. Some block-bearing lithic-pumice-crystal breccias may also reflect more proximal subaqueous silicic explosive eruptions. Crystal-lithic sandstones interbedded with, and overlying the ignimbrites, contain abundant detrital volcanic quartz and feldspar derived from the pyroclastic deposits. Limestone is common in the upper part of the upper facies association, and several beds are oolitic (cf. Rockhampton Group of the Yarrol terrane). Overall, the upper facies association fines upward and is transgressive, recording a return to shallow-marine conditions. Palaeocurrent data from all stratigraphic levels in the Campwyn Volcanics indicate that the regional sediment-dispersal direction was to the northwest, and opposed to the generally accepted notion of easterly sediment dispersal from a volcanic arc source. The silicic upper facies association correlates in age and lithology to Early Carboniferous silicic volcanism in the Drummond (Cycle 1) and Burdekin Basins, Connors Arch, and in the Yarrol terranes of eastern Queensland. The widespread development of silicic volcanism in the Early Carboniferous indicates that silicic (rift-related) magmatism was not restricted to the Drummond Basin, but was part of a more substantial silicic igneous province.

Amino acids 1-20 of the hepatitis C virus (HCV) core protein specifically inhibit HCV IRES- dependent translation in Hep G2 cells, and inhibit both HCV IRES- and cap-dependent translation in HuH7 and CV-1 cells.

A self-modulating mechanism by the hepatitis C virus (HCV) core protein has been suggested to influence the level of HCV replication, but current data on this subject are contradictory. We examined the effect of wild-type and mutated core protein on HCV IRES- and cap-dependent translation. The wild-type core protein was shown to inhibit both IRES- and cap-dependent translation in an in vitro system. This effect was duplicated in a dose-dependent manner with a synthetic peptide representing amino acids 1-20 of the HCV core protein. This peptide was able to bind to the HCV IRES as shown by a mobility shift assay. In contrast, a peptide derived from the hepatitis B virus (HBV) core protein that contained a similar proportion of basic residues was unable to inhibit translation or bind the HCV IRES. A recombinant vaccinia-HCV core virus was used to examine the effect of the HCV core protein on HCV IRES-dependent translation in cells and this was compared with the effects of an HBV core-recombinant vaccinia virus. In CV-1 and HuH7 cells, the HCV core protein inhibited translation directed by the IRES elements of HCV, encephalomyocarditis virus and classical swine fever virus as well as cap-dependent translation, whereas in HepG2 cells, only HCV IRES-dependent translation was affected. Thus, the ability of the HCV core protein to selectively inhibit HCV IRES-dependent translation is cell-specific. N-terminal truncated (aa 1-20) HCV core protein that was expressed from a novel recombinant vaccinia virus in cells abrogated the inhibitory phenotype of the core protein in vivo, consistent with the above in vitro data.

Microstructural evolution of the Serido Belt, NE-Brazil: the effect of two tectonic events on development of c-axis preferred orientation in quartz

The polyphase evolution of the Serido Belt (NE-Brazil) includes D, crust formation at 2.3-2.1 Ga, D-2 thrust tectonics at 1.9 Ga and crustal reworking by D-3 strike-slip shear zones at 600 Ma. Microstructural investigations within mylonites associated with D-2 and D-3 events were used to constrain the tectono-thermal evolution of the belt. D-2 shear zones commenced at deeper crustal levels and high amphibolite facies conditions (600-650 degreesC) through grain boundary migration, subgrain rotation and operation of quartz Q-prism slip. Continued shearing and exhumation of the terrain forced the re-equilibration of high-T fabrics and the switching of slip systems from (c)-prism to positive and negative (a)-rhombs. During D-3, enhancement of ductility by dissipation of heat that came from syn-D-3 granites developed wide belts of amphibolite facies mylonites. Continued shearing, uplift and cooling of the region induced D-3 shear zones to act in ductile-brittle regimes, marked by fracturing and development of thinner belts of greenschist facies mylonites. During this event, switching from (a)-prism to a basal slip indicates a thermal path from 600 to 350 degreesC. Therefore, microstructures and quartz c-axis fabrics in polydeformed rocks from the Serido Belt preserve the record of two major events, which includes contrasting deformation mechanisms and thermal paths. (C) 2003 Elsevier Ltd. All rights reserved.

Deviance and marginal occupations: the case of taxi drivers

The taxi industry provides a strategic site to explore workplace deviance in low supervision, low status, occupational settings. Despite this theoretical opportunity and the objective importance of the taxi industry worldwide, very little is known about deviance among taxi drivers. Making use of interview data, this exploratory study maps out forms of workplace deviance and the explanations given for them by a sample of male taxi drivers. Major illegal activities reported included speeding, driving unsafe vehicles, taking drugs, and fraud. Theories pertaining to worker alienation, stress management, victim precipitation, and social control were relevant to the rationalizations some of the drivers provided to account for their illegal behaviors. We conclude that the occupational culture of taxi drivers and the structure of the taxi industry facilitate the forms of deviance reported here.