bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amyotrophic Lateral Sclerosis Presenting With a Clivus Mass and Dysarthria
Authors: Maragakis Nicholas J , Pardo Andrea C 
Published: December 2006

Abstract:

A patient developed dysarthria and was found to have fibrous dysplasia of the clivus accompanied by cranial nerve impingement, particularly the hypoglossal canal. The dysarthria progressed to more severe bulbar dysfunction and a subsequent diagnosis of amyotrophic lateral sclerosis. This case highlights a discussion of the potential influences of focal lesions on the site of symptom onset in this neurodegenerative disease.
Purification of soluble and active RaxH, a transmembrane histidine protein kinase from Xanthomonas oryzae pv. oryzae required for AvrXa21 activity
Authors: STOLOV AVITAL , VALVERDE ANGEL , RONALD PAMELA , BURDMAN SAUL 
Published: December 2006

SUMMARYThe RaxHR two‐component regulatory system (TCS) of the rice pathogen Xanthomonas oryzae pv. oryzae is required for AvrXa21 activity. RaxH is a typical transmembrane histidine protein kinase (HK), whereas RaxR is its concomitant response regulator (RR). Here, we report the isolation of soluble, active amounts of recombinant His‐tagged full‐length RaxH and RaxR following growth of Escherichia coli over‐expressing strains in the presence of sorbitol and glycine betaine. Full‐length His‐RaxH showed similar autophosphorylation activities to that of a truncated version of the protein (His‐t‐RaxH), lacking the N‐terminal transmembrane region. Transphosphorylation assays revealed that only full‐length RaxH was able to induce phosphorylation of His‐RaxR, indicating that the N‐terminal region of RaxH may be required for transphosphorylation of RaxR. Using site‐directed mutagenesis we also demonstrated that residues histidine 222 in RaxH and aspartate 51 in RaxR are essential for phosphorylation activities of these proteins. Utilization of compatible solutes may be widely applied for purification of soluble, active recombinant transmembrane proteins, and in particular for purification of transmembrane HKs.
Disease resistance to bacterial pathogens affected by the amount of ferredoxin‐I protein in plants
Authors: HUANG HSIANG‐EN , GER MANG‐JYE , CHEN CHAO‐YING , PANDEY AJAY‐KUMAR , YIP MEI‐KUEN , CHOU HUNG‐WEN , FENG TENG‐YUNG 
Published: December 2006

SUMMARYFerredoxin‐I (Fd‐I) is a fundamental protein that is involved in several metabolic pathways. The amount of Fd‐I found in plants is generally regulated by environmental stress, including biotic and abiotic events. In this study, the correlation between quantity of Fd‐I and plant disease resistance was investigated. Fd‐I levels were increased by inoculation with Pseudomonas syringae pv. syringae but were reduced by Erwinia carotovora ssp. carotovora. Transgenic tobacco over‐expressing Fd‐I with the sense sweet pepper Fd‐I gene (pflp) was resistant to E. carotovora ssp. carotovora and the saprophytic bacterium P. fluorescens. By contrast, transgenic tobacco with reduced total Fd‐I and the antisense pflp gene was susceptible to E. carotovora ssp. carotovora and P. fluorescens. Both of these transgenic tobaccos were resistant to P. syringae pv. syringae. By contrast, the mutated E. carotovora ssp. carotovora, with a defective harpin protein, was able to invade the sense‐pflp transgenic tobacco as well as the non‐transgenic tobacco. An in vitro kinase assay revealed that harpin could activate unidentified kinases to phosphorylate PFLP. These results demonstrate that Fd‐I plays an important role in the disease defence mechanism.
Costs of caring for a child with cancer: a questionnaire survey
Authors: Eiser C. , Upton P. 
Published: December 2006

AbstractBackground  Current therapies for childhood cancer have resulted in improved survival rates. However, this has been achieved at considerable price to families, with financial costs including additional expenditure and loss of earnings having been described. The impact of these extra costs for UK families and the extent to which help from charities and government benefits is able to alleviate this is unknown.Methods  Questionnaires concerning income, expenditure, employment and financial support were completed by 145 parents, recruited from three United Kingdom Children’s Cancer Study Group treatment centres.Results  Parents’ responses highlighted increased expenditure related mainly to travel to treatment centres. The majority of families (55%) had spent between £50–100 in the past week over and above pre‐illness expenditure, with a further 18% spending more than £100. Many parents (mainly mothers) had either given up or reduced outside employment in order to care for their child and this was associated with further financial problems for 42.7% of families. Despite help from charities and government benefits for the majority of families, extra costs were associated with money worries for 68.3% of families.Conclusions  Although families are offered timely information about their entitlement to benefits, financial problems are incurred by families of a child with cancer partly because legislation prevents benefits being claimed for the first 3 months of a child’s illness – the time when expenses are still at their highest. Furthermore, because benefits are backdated only to the point at which the claim was made, families do not recoup all their costs. Waiving of the 84‐day wait period for children undergoing chemotherapy and radiotherapy, and the introduction of weekly bridging payments while a Disability Living Allowance claim is being assessed, would ameliorate this problem and so improve the treatment experience for families.
Antigen‐specific immunoglobulin E+ B cells are preferentially localized within germinal centres
Authors: Kelly Kathleen A. , Butch Anthony W. 
Published: December 2006

SummaryAllergen‐specific immunoglobulin E (IgE) mediates immediate‐type hypersensitivity reactions and plays a central role in allergic diseases. Although antigen‐driven B‐cell maturation and isotype switching occur within germinal centres (GCs), the role of GCs in IgE production is poorly understood. In view of this, we investigated the development of IgE‐expressing cells within GCs in response to an extensively characterized antigen, 2‐phenyloxazolone (phOx). The phOx‐specific IgE‐expressing cells localized within GCs 7 days after immunization, and peaked in number on day 11. Surprisingly, very few IgE‐positive cells were found in the T‐cell areas of the lymph node. Flow cytometric studies confirmed that IgE was expressed by B cells and was not the result of trapping by follicular dendritic cells. The specificity of the antibody response was confirmed by microdissection and reverse transcription‐polymerase chain reaction using phOx‐specific IgE primers. IgE‐positive cells were primarily found within GCs while, in contrast, many IgG1‐positive cells could also be detected outside GCs in the T‐cell areas. Taken together, these data highlight the importance of GCs in the production of antigen‐specific IgE antibody.
Compatible genetic and ecological estimates of dispersal rates in insect (Coenagrion mercuriale: Odonata: Zygoptera) populations: analysis of ‘neighbourhood size’ using a more precise estimator
Authors: WATTS PHILLIP C. , ROUSSET FRANÇOIS , SACCHERI ILIK J. , LEBLOIS RAPHAËL , KEMP STEPHEN J. , THOMPSON DAVID J. 
Published: December 2006

AbstractGenetic and demographic estimates of dispersal are often thought to be inconsistent. In this study, we use the damselfly Coenagrion mercuriale (Odonata: Zygoptera) as a model to evaluate directly the relationship between estimates of dispersal rate measured during capture–mark–recapture fieldwork with those made from the spatial pattern of genetic markers in linear and two‐dimensional habitats. We estimate the ‘neighbourhood size’ (Nb) — the product of the mean axial dispersal rate between parent and offspring and the population density — by a previously described technique, here called the regression method. Because C. mercuriale is less philopatric than species investigated previously by the regression method we evaluate a refined estimator that may be more applicable for relatively mobile species. Results from simulations and empirical data sets reveal that the new estimator performs better under most situations, except when dispersal is very localized relative to population density. Analysis of the C. mercuriale data extends previous results which demonstrated that demographic and genetic estimates of Nb by the regression method are equivalent to within a factor of two at local scales where genetic estimates are less affected by habitat heterogeneity, stochastic processes and/or differential selective regimes. The corollary is that with a little insight into a species’ ecology the pattern of spatial genetic structure provides quantitative information on dispersal rates and/or population densities that has real value for conservation management.
Multiple scales of genetic connectivity in a brooding coral on isolated reefs following catastrophic bleaching
Authors: UNDERWOOD J. N. , SMITH L. D. , VAN OPPEN M. J. H. , GILMOUR J. P. 
Published: December 2006

AbstractUnderstanding the pattern of connectivity among populations is crucial for the development of realistic and spatially explicit population models in marine systems. Here we analysed variation at eight microsatellite loci to assess the genetic structure and to infer patterns of larval dispersal for a brooding coral,Seriatopora hystrix, at an isolated system of reefs in northern Western Australia. Spatial autocorrelation analyses show that populations are locally subdivided, and that the majority of larvae recruit to within 100 m of their natal colony. Further, a combination ofF‐ andR‐ statistics showed significant differentiation at larger spatial scales (2–60 km) between sites, and this pattern was clearly not associated with distance. However, Bayesian analysis demonstrated that recruitment has been supplemented by less frequent but recent input of larvae from outside the local area; 2–6% of colonies were excluded from the site at which they were sampled. Individual assignments of these migrants to the most likely populations suggest that the majority of migrants were produced at the only site that was not decimated by a recent and catastrophic coral bleaching event. Furthermore, the only site that recovered to prebleaching levels received most of these immigrants. We conclude that the genetic structure of this brooding coral reflects its highly opportunistic life history, in which prolific, philopatric recruitment is occasionally supplemented by exogenously produced larvae.
Indole signalling contributes to the stable maintenance of Escherichia coli multicopy plasmids
Authors: Chant Eleanor L. , Summers David K. 
Published: December 2006

SummaryThe efficient transmission of multicopy plasmids to daughter cells at division requires that a high copy number is maintained. Plasmid multimers depress copy number, thereby causing instability. Various mechanisms exist to counter multimerization and thus ensure stable maintenance. One well‐studied example is the multimer resolution system of the Escherichia coli plasmid ColE1 which carries a recombination site (cer) at which multimers are resolved to monomers by the XerCD recombinase. A promoter within cer initiates synthesis of a short transcript (Rcd) in multimer‐containing cells. The Rcd checkpoint hypothesis proposes that Rcd delays cell division until multimer resolution is complete. We have identified tryptophanase (which catabolizes tryptophan to pyruvate and indole) as an Rcd binding protein. Furthermore, the stabilization of multicopy plasmids by Rcd is shown to be tryptophanase dependent, and a tryptophanase‐deficient strain is resistant to growth inhibition by Rcd overexpression. Rcd increases the affinity of tryptophanase for its substrate tryptophan which causes increased indole production by cells in low‐density cultures. Thus Rcd‐mediated stabilization of multicopy plasmids is dependent upon indole acting as a signalling molecule. This is an novel role for this molecule which previously has been implicated in quorum sensing‐like processes at high cell density.
DinI and RecX modulate RecA–DNA structures in Escherichia coli K‐12
Authors: Renzette Nicholas , Gumlaw Nathan , Sandler Steven J. 
Published: December 2006

SummaryRecA plays a central role in recombination, DNA repair and SOS induction through forming a RecA–DNA helical filament. Biochemical observations show that at low ratios to RecA, DinI and RecX stabilize and destabilize RecA–DNA filaments, respectively, and that the C‐terminal 17 residues of RecA are important for RecX function. RecA–DNA filament formation was assayed in vivo using RecA–GFP foci formation in log‐phase and UV‐irradiated cells. In log‐phase cells, dinI mutants have fewer foci than wild type and that recX mutants have more foci than wild type. A recAΔ17::gfp mutant had more foci like a recX mutant. dinI recX double mutants have the same number of foci as dinI mutants alone, suggesting that dinI is epistatic to recX. After UV treatment, the dinI, recX and dinI recX mutants differed in their ability to form foci. All three mutants had fewer foci than wild type. The dinI mutant's foci persisted longer than wild‐type foci. Roles of DinI and RecX after UV treatment differed from those during log‐phase growth and may reflect the different DNA substrates, population of proteins or amounts during the SOS response. These experiments give new insight into the roles of these proteins.
Aspergillus nidulans VeA subcellular localization is dependent on the importin α carrier and on light
Authors: Stinnett Suzanne M. , Espeso Eduardo A. , Cobeño Laura , Araújo‐Bazán Lidia , Calvo Ana M. 
Published: December 2006

SummaryThe veA gene is a light‐dependent regulator governing development and secondary metabolism in Aspergillus nidulans. We have identified a putative bipartite nuclear localization signal (NLS) motif in the A. nidulans VeA amino acid sequence and demonstrated its functionality when expressed in yeast. Furthermore, migration of VeA to the nucleus was dependent on the importin α. This bipartite NLS is also functional when VeA is expressed in A. nidulans. Interestingly, we found that VeA migration to the nucleus is light‐dependent. While in the dark VeA is located mainly in the nuclei, under light VeA is found abundantly in the cytoplasm. The VeA1 mutant protein (lacking the first 36 amino acids at the N‐terminus) was found predominantly in the cytoplasm independent of illumination. This indicates that the truncated bipartite NLS in VeA1 is not functional and fails to respond to light. These results might explain the lack of the morphological light‐dependent response in strains carrying the veA1 allele. We also evaluated the effect of light on production of the mycotoxin sterigmatocystin in a veA wild‐type and the veA1 mutant strains and found that the highest amount of toxin was produced by the veA+ strain growing in the dark, condition favouring accumulation of VeA in the nucleus.
The dominating outer membrane protein of the hyperthermophilic Archaeum Ignicoccus hospitalis: a novel pore‐forming complex
Authors: Burghardt Tillmann , Näther Daniela J. , Junglas Benjamin , Huber Harald , Rachel Reinhard 
Published: December 2006

SummaryThe membrane protein Imp1227 (Ignicoccus outer membrane protein; Imp1227) is the main protein constituent of the unique outer sheath of the hyperthermophilic, chemolithoautotrophic Archaeum Ignicoccus hospitalis. This outer sheath is the so far only known example for an asymmetric bilayer among the Archaea and is named ‘outer membrane’. With its molecular mass of only 6.23 kDa, Imp1227 is found to be incorporated into the outer membrane in form of large, stable complexes. When separated by SDS‐PAGE, they exhibit apparent masses of about 150, 50, 45 and 35 kDa. Dissociation into the monomeric form is achieved by treatment with SDS‐containing solutions at temperatures at or above 113°C. Electron micrographs of negatively stained samples confirm that isolated membranes are tightly packed with round complexes, about 7 nm in diameter, with a central, stain‐filled 2 nm pore; a local two‐dimensional crystalline arrangement in form of small patches can be detected by tomographic reconstruction. The comparison of the nucleotide and amino acid sequence of Imp1227 with public databases showed no reliable similarities with known proteins. Using secondary structure prediction and molecular modelling, an α‐helical transmembrane domain is proposed; for the oligomer, a ring‐shaped nonamer with a central 2 nm pore is a likely arrangement.
Release of outer membrane vesicles by Gram‐negative bacteria is a novel envelope stress response
Authors: McBroom Amanda J. , Kuehn Meta J. 
Published: December 2006

SummaryConditions that impair protein folding in the Gram‐negative bacterial envelope cause stress. The destabilizing effects of stress in this compartment are recognized and countered by a number of signal transduction mechanisms. Data presented here reveal another facet of the complex bacterial stress response, release of outer membrane vesicles. Native vesicles are composed of outer membrane and periplasmic material, and they are released from the bacterial surface without loss of membrane integrity. Here we demonstrate that the quantity of vesicle release correlates directly with the level of protein accumulation in the cell envelope. Accumulation of material occurs under stress, and is exacerbated upon impairment of the normal housekeeping and stress‐responsive mechanisms of the cell. Mutations that cause increased vesiculation enhance bacterial survival upon challenge with stressing agents or accumulation of toxic misfolded proteins. Preferential packaging of a misfolded protein mimic into vesicles for removal indicates that the vesiculation process can act to selectively eliminate unwanted material. Our results demonstrate that production of bacterial outer membrane vesicles is a fully independent, general envelope stress response. In addition to identifying a novel mechanism for alleviating stress, this work provides physiological relevance for vesicle production as a protective mechanism.
Conjugative transfer can be inhibited by blocking relaxase activity within recipient cells with intrabodies
Authors: Garcillán‐Barcia M. Pilar , Jurado Paola , González‐Pérez Blanca , Moncalián Gabriel , Fernández Luis A. , de la Cruz Fernando 
Published: December 2006

SummaryHorizontal transfer of antibiotic resistance genes carried by conjugative plasmids poses a serious health problem. As conjugative relaxases are transported to recipient cells during bacterial conjugation, we investigated whether blocking relaxase activity in the recipient cell might inhibit conjugation. For that purpose, we used an intrabody approach generating a single‐chain Fv antibody library against the relaxase TrwC of conjugative plasmid R388. Recombinant single‐chain Fv antibodies were engineered for cytoplasmic expression in Escherichia coli cells and either selected in vitro for their specific binding to TrwC, or in vivo by their ability to interfere with conjugation using a high‐throughput mating assay. Several intrabody clones were identified showing specific inhibition against R388 conjugation upon cytoplasmic expression in the recipient cell. The epitope recognized by one of these intrabodies was mapped to a region of TrwC containing Tyr‐26 and involved in the conjugative DNA‐processing termination reaction. These findings demonstrate that the transferred relaxase plays an important role in the recipient cell and open a new approach to identify specific inhibitors of bacterial conjugation.
A gene in European wheat cultivars for resistance to an African isolate of Mycosphaerella graminicola
Authors: Arraiano L. S. , Chartrain L. , Bossolini E. , Slatter H. N. , Keller B. , Brown J. K. M. 
Published: December 2006

Genes for specific resistance to European and American isolates of Mycosphaerella graminicola, the causal agent of septoria tritici blotch (STB) of wheat, have been identified and mapped in various cultivars and breeding lines and are distributed throughout the genome. The location of a gene for resistance to an Ethiopian isolate, IPO88004, which is currently the most widespread resistance present in European wheat cultivars, is reported. The resistance was mapped in the Swiss cultivar Arina which, besides high partial resistance to STB, also has specific resistance to IPO323, controlled by Stb6 and to IPO88004. An F5 recombinant inbred population from a cross between Arina and the susceptible cultivar Forno was tested in whole seedling trials. Using multiple QTL mapping (MQM), a gene for resistance to M. graminicola isolate IPO88004 in cv. Arina was located to chromosome 6AS. The gene is named Stb15. Seedling tests on a double haploid population of cvs Arina × Riband indicated that the UK wheat cv. Riband also has Stb15 or another gene for specific resistance to IPO88004 allelic or closely linked to Stb15.
Long‐term cancer risk of the anorectal cuff following restorative proctocolectomy assessed by p53 expression and cuff dysplasia
Authors: Coull D. B. , Lee F. D. , Anderson J. H. , McKee R. F. , Finlay I. G. , Dunlop M. G. 
Published: December 2006

AbstractObjective  Restorative proctocolectomy (RP) for ulcerative colitis (UC) retains a ‘cuff’ of columnar rectal epithelium that has unknown risk of malignant change. Markers of malignant potential in UC include aberrant p53 expression and dysplasia. We undertook a prospective study comprising serial surveillance biopsy and assessed the occurrence of aberrant p53 expression, epithelial dysplasia and carcinoma in the retained anorectal cuff following stapled RP.Method  A total of 110 patients who underwent stapled RP for UC between 1988 and 1998 were followed up by cuff surveillance biopsies under general anaesthesia. Histological samples were analysed by a specialist colorectal pathologist for the presence of rectal mucosa, dysplasia and carcinoma. Immunohistochemistry for p53 expression was performed for each most recent cuff biopsy. Median follow‐up was 56 months (12–145) and median time since diagnosis of UC was 8.8 years (2–32).Results  Rectal mucosa was obtained from the cuff in 65% of biopsies. No overt carcinomas developed during the follow‐up period and there was no dysplasia or carcinoma in any cuff biopsy. The p53 overexpression was identified in 38 specimens (50.6%), but was also identified in controls (3/3 colitis, 3/3 ileal pouch and 6/6 stapled haemorrhoidectomy donuts).Conclusion  The lack of carcinoma and dysplasia in the columnar cuff epithelium specimens is reassuring. The lack of stabilized p53 and absence of a relationship between p53 stabilization and dysplasia up to 12 years after pouch formation suggests neoplastic transformation is a rare event. Furthermore, p53 expression was not useful in surveillance of cuff biopsies from patients who have undergone RP for UC and the search should continue for alternative predysplastic markers. These data suggest that in patients who do not have high‐grade dysplasia or colorectal cancer at the time of RP, cuff surveillance in the first decade after pouch formation is unnecessary. However, we consider regular cuff surveillance biopsies should continue for patients with high‐grade dysplasia, whether or not there was a carcinoma in the original colectomy specimen.