bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing toxicity of mining effluents: equilibrium- and kinetics-based metal speciation and algal bioassay
Authors: Gopalapillai Yamini , Chakrabarti Chuni L. , Lean David R. S.
Published: August 2008

Environmental context. The release of mining effluents exposes natural waters to excess metals and thereby threatens both human and environmental health. The present study explores the toxicity of aqueous mining effluents collected from a mining area in Sudbury (Ontario, Canada), using two different methods for determination of metal speciation, and an algal toxicity study. The results show reasonable correlation between metal speciation and the observed toxicity and suggest the importance of taking into account other factors related to water quality criteria such as nutrient concentrations, diluent water and presence of other toxic metals that can greatly influence the toxicological result.
Abstract. The present study explores the toxicity of aqueous mining and municipal effluents from the Sudbury area (Canada) using equilibrium- and kinetics-based estimates of metal speciation and chronic toxicity studies using algae (Pseudokirchneriella subcapitata). Free metal ion concentration was determined by the Ion Exchange Technique (IET) and a computer speciation code, Windermere Humic Aqueous Model (WHAM) VI. Labile metal concentration was determined using the Competing Ligand Exchange Method. In general, no correlation was found between the observed IC25 (concentration of test substance that inhibits growth of organism by 25%) and the [Ni]labile, [Ni2+]IET or [Ni2+]WHAM, probably because of contributions by other metals such as Cu and Zn being also significant. Reasonable correlation (r2 = 0.7575) was found when the observed toxicity was compared with the sum of free metal ions of Cu, Ni, and Zn predicted by WHAM. The results of the present study reveal the importance of taking into account other factors related to water quality criteria such as nutrient concentrations, diluent water, and the presence of other toxic metals, which greatly influence the toxicological result in complex, multi-metal contaminated waters.
Hydraulic and chemical signalling in the regulation of stomatal conductance and plant water use in field grapevines growing under deficit irrigation
Authors: Rodrigues M. Lucília , Santos Tiago P. , Rodrigues Ana P. , de Souza Claudia R. , Lopes Carlos M. , Maroco João P. , Pereira João S. , Chaves M. Manuela
Published: August 2008

Effects of irrigation strategies on stomata and plant water use were studied in field-grown grapevines (Vitis vinifera L.). We assessed the importance of root-derived chemical signals vs. hydraulic signalling in stomatal regulation. The experiment included two treatments with the same water added to the soil (50% ETc) applied either to the whole root system (DI) or to half of the roots, alternating irrigation side every 15 days (PRD). Well-watered plants (FI) (100% ETc) and non-irrigated grapevines (NI) were also studied. Partial stomata closure occurred in both PRD and DI plants. [ABA] of xylem sap remained constant during the day and was maintained throughout the season, with higher values in NI plants. Xylem sap pH was not affected by soil water availability. A positive correlation between ψpd and maximum g s was found, indicating that grapevine stomata strongly respond to plant water status. In contrast, ABA did not explain stomatal control at veraison. At mid-ripening g s was significantly correlated with ABA, apparently interacting with the rise in xylem sap pH. Therefore, our data suggest that hydraulic feedback and feed-forward root-to-shoot chemical signalling mechanisms might be involved in the control of stomata in response to decreased soil water availability, hydraulic signals playing the dominant role.
Arabidopsis thaliana MYB75/PAP1 transcription factor induces anthocyanin production in transgenic tomato plants
Authors: Zuluaga Diana Lucia , Gonzali Silvia , Loreti Elena , Pucciariello Chiara , Degl'Innocenti Elena , Guidi Lucia , Alpi Amedeo , Perata Pierdomenico
Published: August 2008

Tomato (Solanum lycopersicum L.) cv. Micro-Tom plants were transformed with the Arabidopsis thaliana (L.)Heyhn. MYB75/PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT 1) gene. This gene encodes for a well known transcription factor, which is involved in anthocyanin production and is modulated by light and sucrose. Transgenic tomato plants expressing AtMYB75 were characterised by a significantly higher anthocyanin production in leaves, stems, roots and flowers under normal growth conditions. Further, they also exhibited anthocyanins in fruits. Anthocyanin accumulation was not widespread but took place in specific groups of cells located in epidermal or cortical regions or in proximity of vascular bundles. In all the organs of the transgenic plants, where AtMYB75 overexpression was determined, a clear increase in the accumulation of DFR (DIHYDROFLAVONOL 4-REDUCTASE) transcript was also detected. The expression of the tomato MYB-gene ANT1 (ANTHOCYANIN1), which had previously been identified as a transcriptional endogenous regulator of anthocyanin biosynthesis, was not altered. The higher basal content of anthocyanins in the leaves of the transgenic plants could be further increased in the presence of high light conditions and contributed to mitigate photobleaching damages under high irradiance.
Multiple traits associated with salt tolerance in lucerne: revealing the underlying cellular mechanisms
Authors: Smethurst Christiane F. , Rix Kieren , Garnett Trevor , Auricht Geoff , Bayart Antoine , Lane Peter , Wilson Stephen J. , Shabala Sergey
Published: August 2008

Salinity tolerance is a complex trait inferring the orchestrated regulation of a large number of physiological and biochemical processes at various levels of plant structural organisation. It remains to be answered which mechanisms and processes are crucial for salt tolerance in lucerne (Medicago sativa L.). In this study, salinity effects on plant growth characteristics, pigment and nutrient composition, PSII photochemistry, leaf sap osmolality, changes in anatomical and electrophysiological characteristics of leaf mesophyll, and net ion fluxes in roots of several lucerne genotypes were analysed. Salinity levels ranged from 40 to ~200 mm NaCl, and were applied to either 2-month-old plants or to germinating seedlings for a period of between 4 and 12 weeks in a series of hydroponic, pot and field experiments. Overall, the results suggest that different lucerne genotypes employ at least two different mechanisms for salt tolerance. Sodium exclusion appeared to be the mechanism employed by at least one of the tolerant genotypes (Ameristand 801S). This cultivar had the lowest leaf thickness, as well as the lowest concentration of Na+ in the leaf tissue. The other tolerant genotype, L33, had much thicker leaves and almost twice the leaf Na+ concentration of Ameristand. Both cultivars showed much less depolarisation of leaf membrane potential than the sensitive cultivars and, thus, had better K+ retention ability in both root and leaf tissues. The implications of the above measurements for screening lucerne germplasm for salt tolerance are discussed.
Heparan sulfate regulates ephrin-A3/EphA receptor signaling
Authors: Irie Fumitoshi , Okuno Misako , Matsumoto Kazu , Pasquale Elena B. , Yamaguchi Yu
Published: August 2008

Increasing evidence indicates that many signaling pathways involve not only ligands and receptors but also various types of coreceptors and matrix components as additional layers of regulation. Signaling by Eph receptors and their ephrin ligands plays a key role in a variety of biological processes, such as axon guidance and topographic map formation, synaptic plasticity, angiogenesis, and cancer. Little is known about whether the ephrin-Eph receptor signaling system is subject to such additional layers of regulation. Here, we show that ephrin-A3 binds to heparan sulfate, and that the presence of cell surface heparan sulfate is required for the full biological activity of ephrin-A3. Among the ephrins tested, including ephrin-A1, -A2, -A5, -B1, and -B2, only ephrin-A3 binds heparin or heparan sulfate. Ephrin-A3-dependent EphA receptor activation is reduced in mutant cells that are defective in heparan sulfate synthesis, in wild-type cells from which cell surface heparan sulfate has been removed, and in the hippocampus of conditional knockout mice defective in heparan sulfate synthesis. Ephrin-A3-dependent cell rounding is impaired in CHO cells lacking heparan sulfate, and cortical neurons lacking heparan sulfate exhibit impaired growth cone collapse. In contrast, cell rounding and growth cone collapse in response to ephrin-A5, which does not bind heparan sulfate, are not affected by the absence of heparan sulfate. These results show that heparan sulfate modulates ephrin/Eph signaling and suggest a physiological role for heparan sulfate proteoglycans in the regulation of ephrin-A3-dependent biological processes.
Structural basis of
Clostridium perfringens
toxin complex formation
Authors: Adams Jarrett J. , Gregg Katie , Bayer Edward A. , Boraston Alisdair B. , Smith Steven P.
Published: August 2008

The virulent properties of the common human and livestock pathogen
Clostridium perfringens
are attributable to a formidable battery of toxins. Among these are a number of large and highly modular carbohydrate-active enzymes, including the μ-toxin and sialidases, whose catalytic properties are consistent with degradation of the mucosal layer of the human gut, glycosaminoglycans, and other cellular glycans found throughout the body. The conservation of noncatalytic ancillary modules among these enzymes suggests they make significant contributions to the overall functionality of the toxins. Here, we describe the structural basis of an ultra-tight interaction (
K
a
= 1.44 × 10
11
M
−1
) between the X82 and dockerin modules, which are found throughout numerous
C. perfringens
carbohydrate-active enzymes. Extensive hydrogen-bonding and van der Waals contacts between the X82 and dockerin modules give rise to the observed high affinity. The μ-toxin dockerin module in this complex is positioned ≈180° relative to the orientation of the dockerin modules on the cohesin module surface within cellulolytic complexes. These observations represent a unique property of these clostridial toxins whereby they can associate into large, noncovalent multitoxin complexes that allow potentiation of the activities of the individual toxins by combining complementary toxin specificities.
Interferon-α initiates type 1 diabetes in nonobese diabetic mice
Authors: Li Qing , Xu Baohui , Michie Sara A. , Rubins Kathleen H. , Schreriber Robert D. , McDevitt Hugh O.
Published: August 2008

With the goal of identifying changes in gene expression in CD4+T cells during the development of diabetes in the nonobese diabetic (NOD) mouse, we used DNA microarrays to analyze gene expression in CD4+T cells from the pancreatic draining lymph nodes of NOD/BDC 2.5 T cell receptor transgenic and WT NOD mice at different ages. At 4 and 6 weeks of age, we found up-regulation of a number of genes that are known to be induced by IFN-α. IFN-α levels and IFN-α–producing plasmacytoid dendritic cells were increased in the PLNs of 3- to 4-week-old NOD mice. Moreover, blockade of IFN-α receptor 1 in NOD mice by a neutralizing antibody at 2–3 weeks of age significantly delayed the onset and decreased the incidence of type 1 diabetes, increased the relative number of immature dendritic cells in the PLNs, and enhanced the ability of spleen CD4+T cells to produce IL-4 and IL-10. These findings demonstrate that IFN-α in the PLNs is an essential initiator in the pathogenesis of type 1 diabetes in NOD mice.
Freshwater fish habitat science and management in India
Authors: Ghosh S. K. , Ponniah A. G.
Published: August 2008

India is a land of diverse topography, climate and natural resource. There are 12 major rivers and 48 lesser rivers with a total catchment area of 277.6 million ha. The freshwater resources of the country, which are varied, harbor 587 species of finfishes, and account for 9.3 percent of global inland fish production. India's natural capital of fish habitat resource has been eroded as reflected in loss of biodiversity and reduced fish landings.

Studies on the ecology, environment and fisheries of five major river systems, in addition to reservoirs and flood plain lake fisheries, have been conducted with greater focus on water quality and less on physical habitat parameters.

River conservation programs cover major rivers in 10 states of the country; the ‘Ganga Action Plan’ being the most important. These projects target improvement in water quality and not fish habitat. Lack of concern for fish habitat is reflected in the planning of Farakka Barrage, a large dam built to divert the flow of River Ganga (The Ganges) into the Hooghly River, and its impact on the ‘Hilsa’ run. Environmental laws have not achieved desired results for lack of enforcement mechanisms.

Freshwater habitat management in India raises both concern and hope. Concern arises out of the missing elements in current fish habitat research, planning and management of resource. The hope for the future is increasing public awareness on the need for better resource management and environmental conservation. In the backdrop of the learning from implementation of the eco-restoration programmes, the task appears to be not only challenging but also demanding in terms of participation of stakeholders, commitment of resources, backup of research support, monitoring of environmental standards, enforcement of regulations and setting up of priorities in terms of conservation of the natural assets.
High-Resolution Infrared-Vacuum Ultraviolet Photoion and Pulsed Field Ionization-Photoelectron Methods for Spectroscopic Studies of Neutrals and Cations
Authors: Xing Xi , Reed Beth , Kyung Bahng Mi , Wang Peng , Koo Woo Hin , Jong Baek Sun , Shing Lam Chee , Yiu Ng Cheuk
Published: August 2008

We show that by scanning the frequency of a single mode infrared (IR) optical parametric oscillator (IR-OPO) laser to excite the molecular species of interest and fixing the frequency of a vacuum ultraviolet (VUV) laser to photoionize the IR excited species, high-resolution IR spectra of polyatomic neutrals can be obtained with high sensitivity. The fact that this IR-VUV-photoion (IR-VUV-PI) method is based on VUV photoionization probe, and thus, allows the identification of the neutral IR absorber, makes it applicable for IR spectroscopy measurements of isotopemers, radicals, and clusters, which usually exist as impure samples. The highly resolved IR-VUV-PI measurements achieved using the single mode IR-OPO laser have made possible the selection of single rovibrational states of CH3X (X = Br and I), C2H4, and C3H4 for VUV-pulsed field ionization-photoelectron (VUV-PFI-PE) measurements, resulting in rovibrationally resolved photoelectron spectra for these polyatomic molecules. These experiments show that the signal-to-noise ratios of the IR-VUV-PI and IR-VUV-PFI-PE spectra obtained by employing the high-resolution IR-OPO laser are significantly higher than those observed in previous IR-VUV-PI and IR-VUV-PFI-PE studies using a low-resolution IR-OPO laser. Further improvement in sensitivity of IR-VUV-PI and IR-VUV-PFI-PE measurements by using the collinear arrangement of IR-VUV lasers and molecular beam is discussed.
Interaction Between Cytochrome c and the Hapten 2,4-Dinitro-fluorobenzene by Electrospray Ionization Mass Spectrometry
Authors: Wu Bo , Chu Yan-qiu , Dai Zhao-yun , Ding Chuan-fan
Published: August 2008

Allergic contact dermatitis is a delayed hypersensitivity reaction, which results from skin exposure to low molecular weight chemicals such as haptens. To clarify the pathogenic mechanism, electrospray ionization mass spectrometry (ESI-MS) and hydrogen/deuterium (H/D) exchange, as well as UV spectroscopy, were applied to determine the interaction between the model protein cytochrome c (cyt c) and the hapten 2,4-dinitro-fluorobenzene (DNFB). The ESI-MS results demonstrate that the conformation of cyt c can change from native folded state into partially unfolded state with the increase of DNFB. The equilibrium state H/D exchange followed by ESI-MS further confirms the above results. UV spectroscopy indicates that the strong-field coordination between iron of heme (prosthetic group) and His18 or Met80 of cyt c is not obviously affected by the hapten.
Theoretical Study of Reaction Mechanism of 1-Propenyl Radical with NO
Authors: Cheng Xue-li , Zhao Yan-yun , Li Feng , Wu Ren-tao
Published: August 2008

The reaction system of 1-propenyl radical with NO is an ideal model for studying the intermolecular and intramolecular reactions of complex organic free radicals containing C=C double bonds. On the basis of the full optimization of all species with the Gaussian 98 package at the B3LYP/6-311++** level, the reaction mechanism was elucidated extensively using the vibrational mode analysis. There are seven reaction pathways and five sets of small molecule end products: CH2O+CH3CN, CH 2CHCN+H2O, CH3CHO+HCN, CH3CHO+HNC, and CH3CCH+HNO. The channel of C3H5+NOIM1TS1IM2TS2IM3TS3CH3CHO+HCN is thermodynamically most favorable.
Factors Affecting Polymer Translocation Through a Nanopore in a Membrane
Authors: Chen Tao , Lu Teng , Liang Hao-jun
Published: August 2008

Monte Carlo simulations were used to study the translocation of a flexible polymer through a pore in a membrane, assuming an attractive interaction between the monomers and the membrane on the trans side of the membrane and no interaction on the cis side. For the case TTc (the temperature corresponding to the minimum in the translocation time ), the value of decreases with increasing temperature, whereas for T>Tc, increases with increasing temperature. The translocation time depends on the absorbed energy u0 in a nontrivial way. The value of increases initially upon increasing u0 before it begins to decrease. The variation of the translocation time with respect to the solvent quality was also studied. It showed that there is a transition, as the solvent quality improves from "poor" to "good": when ABc (the interaction energy corresponding to the minimum in ), decreases with increasing the value of AB; when AB>c, increases with increasing AB. When the chain length was changed, it was found that when the absorbed energy u0 was greater than uc, was proportional to N1.602; for u0uc, N2.248. As the solvent quality improved from "poor" to "good," the translocation probability increased initially before becoming stable.
Monte Carlo Study on Spontaneous Recoil of Confined DNA Chain
Authors: Xie Yong-jun , Yu Hong-tao , Yang Hai-yang , Wang Yao , Zhang Xing-yuan , Shi Qin-wei
Published: August 2008

A part of a long DNA chain was driven into a confined environment by an electric field, while the rest remains in the higher-entropy region. Upon removal of the field, the chain recoils to the higher-entropy region spontaneously. This dynamical process was investigated by Monte Carlo simulations. The simulation reproduces the experimentally-observed phenomenon that the recoil of the DNA chain is initially slow and gradually increases in speed due to the presence of the confinement-entropic force. The results show that with increasing the dimension or decreasing the spacing of the nanopillars the recoil velocity of the DNA chain will increase. Further analysis suggests that the characteristic entropy per monomer in the confinement is proportional to the area fraction of the free part in the confinement.
Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process
Authors: Song Xiao-lan , He Xi , Yang Hai-ping , Qu Yi-xin , Qiu Guan-zhou
Published: August 2008

BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate (Ba(CH3COO)2) and tetra-butyl titanate (Ti(OC4H9)4) as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and transmission electron microscope (TEM). The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.
The RHO1-specific GTPase-activating Protein LRG1 Regulates Polar Tip Growth in Parallel to Ndr Kinase Signaling inNeurospora
Authors: Vogt Nico , Seiler Stephan
Published: August 2008

Regulation of Rho GTPase signaling is critical for cell shape determination and polarity. Here, we investigated the role of LRG1, a novel member of the GTPase-activating proteins (GAPs) of Neurospora crassa. LRG1 is essential for apical tip extension and to restrict excessive branch formation in subapical regions of the hypha and is involved in determining the size of the hyphal compartments. LRG1 localizes to hyphal tips and sites of septation via its three LIM domains. The accumulation of LRG1 as an apical cap is dependent on a functional actin cytoskeleton and active growth, and is influenced by the opposing microtubule-dependent motor proteins dynein and kinesin-1. Genetic evidence and in vitro GTPase assays identify LRG1 as a RHO1-specific GAP affecting several output pathways of RHO1, based on hyposensitivity to the glucan inhibitor caspofungin, synthetic lethality with a hyperactive β1,3-glucan synthase mutant, altered PKC/MAK1 pathway activities, and hypersensitivity to latrunculin A. The morphological defects of lrg-1 are highly reminiscent to the Ndr kinase/RAM pathway mutants cot-1 and pod-6, and genetic evidence suggests that RHO1/LRG1 function in parallel with COT1 in coordinating apical tip growth.
Phosphatase Inhibitor-2 Balances Protein Phosphatase 1 and Aurora B Kinase for Chromosome Segregation and Cytokinesis in Human Retinal Epithelial Cells
Authors: Wang Weiping , Stukenberg P. Todd , Brautigan David L.
Published: August 2008

Mitosis in Saccharomyces cerevisiae depends on IPL1 kinase, which genetically interacts with GLC8. The metazoan homologue of GLC8 is inhibitor-2 (I-2), but its function is not understood. We found endogenous and ectopic I-2 localized to the spindle, midzone, and midbody of mitotic human epithelial ARPE-19 cells. Knockdown of I-2 by RNA interference produced multinucleated cells, with supernumerary centrosomes, multipolar spindles and lagging chromosomes during anaphase. These defects did not involve changes in levels of protein phosphatase-1 (PP1), and the multinuclear phenotype was rescued by overexpression of I-2. Appearance of multiple nuclei and supernumerary centrosomes required progression through the cell cycle and I-2 knockdown cells failed cytokinesis, as observed by time-lapse microscopy. Inhibition of Aurora B by hesperadin produced multinucleated cells and reduced H3S10 phosphorylation. I-2 knockdown enhanced this latter effect. Partial knockdown of PP1Cα prevented multiple nuclei caused by either knockdown of I-2 or treatment with hesperadin. Expression of enhanced green fluorescent protein-I-2 or hemagglutinin-I-2 made cells resistant to hesperadin. We propose that I-2 acts to enhance Aurora B by inhibiting specific PP1 holoenzymes that dephosphorylate Aurora B substrates necessary for chromosome segregation and cytokinesis. Conserved together throughout eukaryotic evolution, I-2, PP1 and Aurora B function interdependently during mitosis.
Detection and differentiation of Cryptosporidium hominis and Cryptosporidium parvum by dual TaqMan assays
Authors: Jothikumar N. , da Silva A. J. , Moura I. , Qvarnstrom Y. , Hill V. R.
Published: August 2008

Rapid identification of the two major species of Cryptosporidium associated with human infections, Cryptosporidium hominis and Cryptosporidium parvum, is important for investigating outbreaks of cryptosporidiosis. This study reports the development and validation of a real-time PCR TaqMan procedure for detection of Cryptosporidium species and identification of C. hominis and C. parvum in stool specimens. This procedure comprised a generic TaqMan assay targeting the 18S rRNA for sensitive detection of Cryptosporidium species, as well as two other TaqMan assays for identification of C. hominis and C. parvum. The generic Cryptosporidium species assay can be duplexed with the C. parvum-specific assay. The generic Cryptosporidium species assay was able to detect ten Cryptosporidium species and did not cross-react with a panel of ten other protozoan parasites. The generic Cryptosporidium species assay could detect 1–10 oocysts in a 300 μl stool specimen, whilst each of the species-specific TaqMan assays had detection sensitivities that were approximately tenfold higher. The 18S rRNA assay was found to detect Cryptosporidium species in 49/55 DNA extracts from stool specimens containing either C. hominis or C. parvum. The C. hominis TaqMan assay correctly identified C. hominis in 24/31 validation panel specimens containing this species. The C. parvum-specific assay correctly identified C. parvum in 21/24 validation panel specimens containing this species. This real-time PCR procedure was used to detect and identify C. hominis and C. parvum in stool specimens from outbreak investigations in the USA and Botswana, resulting in identification of C. hominis and/or C. parvum in 66/67 stool specimens shown to be positive for these species using other techniques. From the outbreak specimens tested, the TaqMan procedure was found to have a specificity of 94 %. This TaqMan PCR procedure should be a valuable tool for the laboratory diagnosis of cryptosporidiosis caused by C. hominis and C. parvum during outbreak investigations.
Penicillin resistance in the intestinal spirochaete Brachyspira pilosicoli associated with OXA-136 and OXA-137, two new variants of the class D β-lactamase OXA-63
Authors: Mortimer-Jones Sheila M. , Phillips Nyree D. , La Tom , Naresh Ram , Hampson David J.
Published: August 2008

Penicillin resistance mediated by β-lactamase activity has been reported previously in the anaerobic intestinal spirochaete Brachyspira pilosicoli, and a novel class D β-lactamase (OXA-63) hydrolysing oxacillin was described recently in a resistant human strain from France. In the current study, 18 B. pilosicoli strains from Australia and Papua New Guinea were tested for ampicillin and oxacillin susceptibility, and investigated for the presence of the class D β-lactamase gene bla
OXA-63 using PCR. PCR products were amplified from seven human and four porcine strains that were penicillin resistant, but not from seven penicillin-sensitive strains. Sequence analysis of the whole gene amplified from seven of the resistant strains from humans and pigs revealed only minor nucleotide differences among them, but there were significant differences compared with bla
OXA-63. The predicted amino acid sequence of the enzyme from all seven strains had the same key structural motifs as the previously reported OXA-63, but two variants with 94–95 % identity with OXA-63 were identified. OXA-136 had an additional amino acid and 12 other consistent amino acid substitutions compared with OXA-63. OXA-137 had the same differences compared with OXA-63 as OXA-136, but had an additional amino acid substitution at position 16. No structures consistent with integrons or transposons were found in the nucleotide sequences in the vicinity of bla
OXA-136 in partially sequenced B. pilosicoli strain 95/1000, and the GC content (25.2 mol%) of the gene was similar to that of the whole genome. The gene encoding OXA-136 from B. pilosicoli strain Cof-10 conferred penicillin resistance on Escherichia coli. This study shows that penicillin resistance in human and porcine B. pilosicoli strains from Australia is associated with the production of two variants of OXA-63, and that susceptible strains lack the genes encoding OXA-63 or the variants.
Characterization of T-cell immunogenicity of two PE/PPE proteins of Mycobacterium tuberculosis
Authors: Chaitra M. G. , Shaila M. S. , Nayak R.
Published: August 2008

The PE and PPE proteins ofMycobacterium tuberculosisform a source of antigenic variation among different strains of this bacterium. Two of the PE_PGRS protein-encoding genes,rv3812andrv3018c, are expressed in pathogenic mycobacteria and are implicated, respectively, in the persistence of the organism in macrophages and in virulence. Peptides derived from these proteins have been predicted to bind major histocompatibility complex (MHC) class I with high affinity on the basis of immunoinformatics analysis, suggesting a possible role for these proteins in antimycobacterial immunity. In the present work, using DNA constructs containing therv3812andrv3018cgenes ofM. tuberculosis, the immunogenicity of these proteins was demonstrated in BALB/c mice. Immunization with either DNA construct induced a significant number of CD8+-type T cells and a strong Th1-type response, with high gamma interferon (IFN-γ) and low interleukin-4 responses. Three nonameric peptides of Rv3812 and two of Rv3018c elicited a strong T-cell response in an MHC-restricted manner. An epitope-specific response was demonstrated by the lysis of peptide-pulsed antigen-presenting cells, release of perforin and IFN-γproduction. Experimentally, these peptides bound with high affinity to MHC H-2Kdand showed low dissociation rates of peptide–MHC complexes. This study suggests that the identified T-cell epitopes may contribute to immunity against tuberculosis if included in a vaccine.
Secreted subtilisins of Microsporum canis are involved in adherence of arthroconidia to feline corneocytes
Authors: Baldo Aline , Tabart Jérémy , Vermout Sandy , Mathy Anne , Collard Alfred , Losson Bertrand , Mignon Bernard
Published: August 2008

Microsporum canis is a pathogenic fungus that causes a superficial cutaneous infection called dermatophytosis, mainly in cats and humans. The mechanisms involved in adherence of M. canis to epidermis have never been investigated. Here, a model was developed to study the adherence of M. canis to feline corneocytes through the use of a reconstructed interfollicular feline epidermis (RFE). In this model, adherence of arthroconidia to RFE was found to be time-dependent, starting at 2 h post-inoculation and still increasing at 6 h. Chymostatin, a serine protease inhibitor, inhibited M. canis adherence to RFE by 53 %. Moreover, two mAbs against the keratinolytic protease subtilisin 3 (Sub3) inhibited M. canis adherence to RFE by 23 %, suggesting that subtilisins, and Sub3 in particular, are involved in the adherence process.
Structure of a signal transduction regulator, RACK1, from Arabidopsis thaliana
Authors: Ullah Hemayet , Scappini Erica Louise , Moon Andrea Florence , Williams Latanya Veronica , Armstrong David Lee , Pedersen Lars Christian
Published: August 2008

The receptor for activated C‐kinase 1 (RACK1) is a highly conserved WD40 repeat scaffold protein found in a wide range of eukaryotic species from Chlamydymonas to plants and humans. In tissues of higher mammals, RACK1 is ubiquitously expressed and has been implicated in diverse signaling pathways involving neuropathology, cellular stress, protein translation, and developmental processes. RACK1 has established itself as a scaffold protein through physical interaction with a myriad of signaling proteins ranging from kinases, phosphatases, ion channels, membrane receptors, G proteins, IP3 receptor, and with widely conserved structural proteins associated with the ribosome. In the plant Arabidopsis thaliana, RACK1A is implicated in diverse developmental and environmental stress pathways. Despite the functional conservation of RACK1‐mediated protein–protein interaction‐regulated signaling modes, the structural basis of such interactions is largely unknown. Here we present the first crystal structure of a RACK1 protein, RACK1 isoform A from Arabidobsis thaliana, at 2.4 Å resolution, as a C‐terminal fusion of the maltose binding protein. The structure implicates highly conserved surface residues that could play critical roles in protein–protein interactions and reveals the surface location of proposed post‐transcriptionally modified residues. The availability of this structure provides a structural basis for dissecting RACK1‐mediated cellular signaling mechanisms in both plants and animals.
Parenting interventions and the prevention of unintentional injuries in childhood: systematic review and meta‐analysis
Authors: Kendrick D. , Barlow J. , Hampshire A. , Stewart‐Brown S. , Polnay L.
Published: August 2008

Objectives  To evaluate the effectiveness of parenting interventions in preventing unintentional injury and increasing parental safety practices.

Data sources  A range of medical and social science electronic databases were searched. Abstracts from the first to seventh World conferences on injury prevention and control and the journal Injury Prevention were hand searched.

Review methods  Randomized controlled trials (RCTs), non‐randomized controlled trials (non‐RCTs) and controlled before and after studies, providing parenting interventions to parents of children aged 0–18 years and reporting injuries, safety equipment or safety practices were included. Studies were selected, data extracted and quality appraised independently by two reviewers. Pooled relative risks were estimated using random effect models.

Results  Fifteen studies (11 RCTs) were included, 11 of which were home visiting programmes and two of which were paediatric practice‐based interventions. Thirteen studies recruited families at risk of adverse child health outcomes. Intervention arm families had a significantly lower risk of injury (RR 0.82, 95% CI 0.71–0.95), as measured by self‐report of medically or non‐medically attended injury. Several studies found fewer home hazards, a home environment more conducive to child safety, or a greater number of safety practices in intervention arm families.

Conclusions  Parenting interventions, most commonly provided within the home, using multi‐faceted interventions appear to be effective in reducing unintentional child injury. Further research is required to explore the mechanisms by which parenting interventions reduce injury, the features of interventions that are necessary to reduce injury, and their generalizability to different population groups.
ADHD and transition to adult services – the experience of community paediatricians
Authors: Marcer H. , Finlay F. , Baverstock A.
Published: August 2008

Background  Attention Deficit Hyperactivity Disorder (ADHD) is now recognized as a disorder that can persist into adulthood, and therefore, there is a need for transitional care.

Aim  To find out about the experiences of community pediatricians across the UK when transferring patients with ADHD to adult care.

Method  A questionnaire was sent out to 100 consultant community pediatricians asking about their experiences.

Results  The majority of respondents thought a proportion of their patients would require referral to adult services and only 22% were aware of a dedicated clinic for adults in their area. Many had tried to address the issue locally often with little success.

Conclusion  There is a gap in provision of services for young people with ADHD when they leave pediatric care, with many pediatricians struggling to find appropriate ongoing care for their patients. Commissioners need to address the problem.
The role of evaluation in the development of a service for children with life‐limiting conditions in the community
Authors: Whitton C. , Williams C. , Wright B. , Jardine J. , Hunt A.
Published: August 2008

Background  Much of the care for children and young people with life‐limiting conditions is now delivered in the home and new services have developed to support families in this setting. It is essential to monitor and evaluate whether these services are meeting the needs of families.

Aims  To evaluate a new rural community palliative care service for children according to the perceptions of families and service providers, to make changes suggested by families and to re‐evaluate 1 year later.

Method  In 2005, 2 years after the onset of the service, 24 families were sent postal questionnaires, including the Measure of Process of Care (MPOC‐UK). Changes suggested by families were then implemented. In 2006, all of the families receiving care from the service (n = 27) were given the option of completing the questionnaire independently or with the support of an impartial researcher. Two families also completed qualitative interviews about their experience of the service with an impartial researcher. In both years, the service providers, (n = 12 and n = 15, respectively) were asked to complete the Measure of Process of Care for Service Providers (MPOC‐SP). The service providers were the clinicians providing direct care (paediatrician, community nurses, dietician, psychologist, occupational therapist, physiotherapist, and speech and language therapist).

Results  Seven (29%) of families completed the survey in 2005. Families rated ‘respectful and supportive care’ as the highest domain in the MPOC‐UK and ‘providing general information’ as the lowest. Particular emphasis was placed on improving provision of information during the following year. Fourteen (52%) families completed the survey in 2006. Scores increased across all domains in the second survey. The largest increase was ‘providing general information’.

Conclusion  The results from both of the MPOC tools were extremely useful in helping providers to identify aspects of the service in need of improvement and hence implement valued changes.
Behaviour problems and social competence deficits associated with symptoms of attention‐deficit/hyperactivity disorder: effects of age and gender
Authors: Thorell L. B. , Rydell A‐M.
Published: August 2008

Background  Previous research has shown that children with high levels of attention‐deficit/hyperactivity disorder (ADHD) symptoms often have a wide variety of associated behaviour problems. However, relatively little is known regarding to what extent these associated behaviour problems are present to the same degree in younger as well as older children and in girls as well as in boys.

Methods  This study used parent ratings to examine effects of age and gender on behaviour problems, social competence, negative impact on everyday life, and family burden among pre‐school and school‐aged children high in ADHD symptoms (n = 60) and comparison children (n = 499).

Results  With regard to age, the pre‐school children did not differ from the school‐aged children on any of the different types of problem behaviour or with regard to social competence. The interactions between age and group were not significant. The behaviour problems of older children did, however, have more negative impact on the child's daily life and induced higher levels of family burden compared with problems of younger children, especially among children with high levels of ADHD symptoms. Boys were more severely affected than girls with regard to ADHD symptom severity, most associated problem behaviours, as well as negative impact and family burden. Significant interactions of ADHD symptoms and gender were also found, which indicated that gender differences were primarily found among children with high levels of ADHD symptoms.

Conclusions  Children with high levels of ADHD symptoms have many associated behaviour problems, even in pre‐school years, and boys with high levels of ADHD symptoms are more severely affected compared with girls.
The IGF system and cytokine interactions and relationships with longitudinal growth in prepubertal patients with cystic fibrosis
Authors: Street Maria E. , Spaggiari Cinzia , Volta Cecilia , Ziveri Maria Angela , Viani Isabella , Rossi Maurizio , Pisi Giovanna , Grzincich GianLuigi , Bernasconi Sergio
Published: August 2008

Objective  Growth delay is a feature of patients with cystic fibrosis (CF). CF is a condition characterized by chronic inflammation that has been shown to modify the IGF system, which is essential for normal growth, and is related to pulmonary function in CF patients. We aimed to verify whether circulating levels of tumour necrosis factor (TNF)‐α, interleukin (IL)‐6, insulin and the IGF system were related and/or had relationships with linear growth in children with CF.

Design and patients  Seventeen prepubertal CF patients (nine males and eight females) in a stable clinical condition were enrolled. Auxological parameters, pulmonary function and the Shwachman–Kulczycki (S‐K) score were assessed, and serum samples were drawn at baseline and after 12 months.

Measurements  TNF‐α, IL‐6, IGF‐I, IGF‐II, IGFBP‐1, IGFBP‐2, IGFBP‐3 and insulin were assayed using specific commercial kits.

Results  At baseline, TNF‐α serum concentration was related to serum IGF‐I concentration (R = 0·53), IGF‐II bioactivity (IGF‐II/IGFBP‐3 molar ratio, R = +0·52) and insulin concentration (R = +0·63). Changes in serum IL‐6 and IGFBP‐2 concentrations during the 12‐month observation were positively correlated (R = +0·63). Changes in height standard deviation score (Ht SDS) were correlated with IGF‐I serum concentrations at baseline (R =+0·67) and after 12 months (R = +0·70), with IGF‐I bioavailability and with IGFBP‐1 serum concentrations (R = –0·88). Body mass index (BMI) SDS correlated with IGF bioavailability.

Conclusions  This study showed a relationship between inflammatory status and the IGF system, and an effect of these interactions on longitudinal growth. Moreover, a role for insulin in growth was identified. Better control of inflammation and preservation of insulin secretion could benefit these patients.
Explicating Benner’s concept of expert practice: intuition in emergency nursing
Authors: Lyneham Joy , Parkinson Camillus , Denholm Carey
Published: August 2008

Title.  Explicating Benner’s concept of expert practice: intuition in emergency nursing.

Aim.  This paper is a report of a study exploring the experience of intuition in emergency nursing in relation to Benner’s fifth stage of practice development, ‘the expert practitioner.’

Background.  Expert nurses anecdotally report actions and thoughts that present in their consciousness and have an impact on the care given. Benner used the term ‘intuition’ for the fifth stage of practice development. However, Paley has criticized Benner’s model for its lack of clarity about the nature of an expert practitioner. This criticism is further justified by Benner’s inadequate explanation of expert.

Method.  A hermeneutic phenomenological study was conducted using van Manen’s approach and a Gadamerian analysis. Fourteen expert emergency nurses in Australia were interviewed between January 2000 and December 2003.

Findings.  The analysis resulted in the reconstruction of Benner’s expert stage into three distinct phases: cognitive intuition, where assessment is processed subconsciously and can be rationalized in hindsight; transitional intuition, where a physical sensation and other behaviours enter the nurse’s awareness; and embodied intuition, when the nurse trusts the intuitive thoughts.

Conclusion.  The findings validate the use of intuitive decision‐making as a construct in explaining expert clinical decision‐making practices. The validity of intuitive practice should be recognized. It is essential to recognize the conditions that support practice development, and in the prenovice stage (during their university course) factors such as reflection, research (in its broadest sense) and clinical curiosity should be fostered.
Reading, writing and systematic review
Authors: Sandelowski Margarete
Published: August 2008

Title.  Reading, writing and systematic review.

Aim.  This paper offers a discussion of the reading and writing practices that define systematic review.

Background.  Although increasingly popular, systematic review has engendered a critique of the claims made for it as a more objective method for summing up research findings than other kinds of reviews.

Discussion.  An alternative understanding of systematic review is as a highly subjective, albeit disciplined, engagement between resisting readers and resistant texts. Reviewers of research exemplify the resisting reader when they exclude reports on grounds of relevance, quality, or methodological difference. Research reports exemplify resistant texts as they do not simply yield their findings, but rather must be made docile to review. These acts of resistance make systematic review possible, but challenge claims of its greater capacity to control bias.

Conclusion.  An understanding of the reading and writing practices that define systematic review still holds truth and objectivity as regulative ideals, but is aware of the reading and writing practices that both enable and challenge those ideals.
Tectonic features of the Lipari–Vulcano complex (Aeolian archipelago, Italy) from 10 years (1996–2006) of GPS data
Authors: Mattia Mario , Palano Mimmo , Bruno Valentina , Cannavò Flavio , Bonaccorso Alessandro , Gresta Stefano
Published: August 2008

The tectonic deformation of the Lipari–Vulcano complex, one of the most important active volcanic areas of the Mediterranean region, is studied here through the analysis of 10 years (1996–2006) of GPS data from both three permanent and 13 non‐permanent stations. This area can be considered crucial for the understanding of the interaction between the Eurasian and African plates in the Mediterranean area, and, in general, this work emphasizes a methodological approach, already applied in other areas worldwide (J. Geophys. Res., 1996, 101, 27 957; J. Geodyn., 1999, 27, 213) where geodetic data and strain parameters maps of critical areas can help to improve our understanding of their geodynamical aspects. In this framework, this study is aimed at providing a kinematic deformation model on the basis of the dense geodetically estimated velocities of the Lipari–Vulcano complex. In particular, the observed deformation pattern can be described by a combination of (1) the main N–S regional compression and (2) a NNE–SSW compression with a small right‐lateral strike slip component acting along a tectonic structure trending N°40W between the two islands. This pattern was inspected through a simplified synthetic model.