bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic‐diGMP signal transduction systems in Vibrio cholerae: modulation of rugosity and biofilm formation
Authors: Lim Bentley , Beyhan Sinem , Meir James , Yildiz Fitnat H. 
Published: March 2006

SummaryCyclic di‐guanylic acid (c‐diGMP) is a second messenger that modulates the cell surface properties of several microorganisms. Concentrations of c‐diGMP in the cell are controlled by the opposing activities of diguanylate cyclases and phosphodiesterases, which are carried out by proteins harbouring GGDEF and EAL domains respectively. In this study, we report that the cellular levels of c‐diGMP are higher in the Vibrio cholerae rugose variant compared with the smooth variant. Modulation of cellular c‐diGMP levels by overexpressing proteins with GGDEF or EAL domains increased or decreased colony rugosity respectively. Several genes encoding proteins with either GGDEF or EAL domains are differentially expressed between the two V. cholerae variants. The generation and characterization of null mutants of these genes (cdgA–E, rocS and mbaA) revealed that rugose colony formation, exopolysaccharide production, motility and biofilm formation are controlled by their action. Furthermore, epistasis analysis suggested that cdgC, rocS and mbaA act in convergent pathways to regulate the phenotypic properties of the rugose and smooth variants, and are part of the VpsR, VpsT and HapR signal transduction pathway.
The enteropathogenic Escherichia coli type III secretion system effector Map binds EBP50/NHERF1: implication for cell signalling and diarrhoea
Authors: Simpson Nandi , Shaw Rob , Crepin Valerie F. , Mundy Rosanna , FitzGerald Anthony J. , Cummings Nicola , Straatman‐Iwanowska Ania , Connerton Ian , Knutton Stuart , Frankel Gad 
Published: March 2006

SummaryEnteropathogenic Escherichia coli (EPEC) is the single most important contributor to child diarrhoea in developing countries. Nevertheless, the mechanism responsible for EPEC diarrhoea remains elusive. Using the yeast two‐hybrid system to determine the target host cell protein of the EPEC type III secretion system effector Map led to identification of ezrin/radixin/moesin (ERM)‐binding phosphoprotein 50 (EBP50), also known as Na+/H+ exchanger regulatory factor 1 (NHERF1). Protein interaction is mediated by the carboxy‐terminal Thr‐Arg‐Leu (TRL) motif of Map and the PSD‐95/Disk‐large/ZO‐1 domain 1 (PDZ1) of EBP50/NHERF1. Although EBP50/NHERF1 is recruited to site of EPEC adhesion in a Map‐independent mechanism, co‐immunoprecipitation and immunostaining revealed that Map binds to, induces proteolysis of, and colocalizes with EBP50/NHERF1 during infection of cultured epithelial cells. The TRL motif of Map was involved in Map‐induced filopodia formation and brush border elongation on infected HeLa and Caco‐2 cells respectively. As EBP50/NHERF1 regulates ion channels in the intestine we assessed the involvement of Map in diarrhoea using the Citrobacter rodentium mouse model of EPEC. We report significantly greater diarrhoea following infections with wild‐type C. rodentium compared with C. rodentiumΔmap. These results provide new insights into the mechanisms of EPEC diarrhoea.
Influences on gene expression in vivo by a Shine–Dalgarno sequence
Authors: Jin Haining , Zhao Qing , Gonzalez de Valdivia Ernesto I. , Ardell David H. , Stenström Magnus , Isaksson Leif A. 
Published: March 2006

SummaryThe Shine–Dalgarno (SD+: 5′‐AAGGAGG‐3′) sequence anchors the mRNA by base pairing to the 16S rRNA in the small ribosomal subunit during translation initiation. We have here compared how an SD+ sequence influences gene expression, if located upstream or downstream of an initiation codon. The positive effect of an upstream SD+ is confirmed. A downstream SD+ gives decreased gene expression. This effect is also valid for appropriately modified natural Escherichia coli genes. If an SD+ is placed between two potential initiation codons, initiation takes place predominantly at the second start site. The first start site is activated if the distance between this site and the downstream SD+ is enlarged and/or if the second start site is weakened. Upstream initiation is eliminated if a stable stem‐loop structure is placed between this SD+ and the upstream start site. The results suggest that the two start sites compete for ribosomes that bind to an SD+ located between them. A minor positive contribution to upstream initiation resulting from 3′ to 5′ ribosomal diffusion along the mRNA is suggested. Analysis of the E. coli K12 genome suggests that the SD+ or SD‐like sequences are systematically avoided in the early coding region suggesting an evolutionary significance.
Antibody responses and epitope specificities to the Taenia solium cysticercosis vaccines TSOL18 and TSOL45‐1A
Authors: KYNGDON C. T. , GAUCI C. G. , GONZALEZ A. E. , FLISSER A. , ZOLI A. , READ A. J. , MARTÍNEZ‐OCAÑA J. , STRUGNELL R. A. , LIGHTOWLERS M. W. 
Published: March 2006

SUMMARYTaenia solium is a cestode parasite that causes cysticercosis in humans and pigs. This study examined the antibody responses in pigs immunized with the TSOL18 and TSOL45‐1A recombinant vaccines against T. solium cysticercosis. Immunization with these proteins induced specific, complement‐fixing antibodies against the recombinant antigens that are believed to be associated with vaccine‐induced protection against T. solium infection. Sera from immunized pigs were used to define the linear B‐cell epitopes of TSOL18 and TSOL45‐1A. Prominent reactivity was revealed to one linear epitope on TSOL18 and two linear epitopes on TSOL45‐1A. These, and oncosphere antigens from other taeniid cestodes, contain a protein sequence motif suggesting that they may show a tertiary structure similar to the fibronectin type III domain (FnIII). Comparison of the location of linear antigenic epitopes in TSOL18 and TSOL45‐1A within the proposed FnIII structure to those within related cestode vaccine antigens reveals conservation in the positioning of the epitopes between oncosphere antigens from different taeniid species.
Evaluation of otoscope cone cleaning and disinfection procedures commonly used in veterinary medical practices: a pilot study
Authors: Newton Heide M. , Rosenkrantz Wayne S. , Muse Russell , Griffin Craig E. 
Published: March 2006

AbstractThe objective of this study was to evaluate the relative efficacy of otoscope cone cleaning and disinfection methods commonly used in veterinary practices. Using sterile technique, 60 new gas‐sterilized 4‐mm otoscope cones were inoculated with a broth culture of 1.5 billionPseudomonas aeruginosabacteria per mL then allowed to dry for 10 min. Six study groups of 10 cones each were created. Group 1 served as positive control and received no cleaning or disinfection. Group 2 cones were wiped with sterile cotton‐tipped applicators and gauze then rinsed with water. Group 3 cones were wiped with 70% isopropyl alcohol. Group 4 cones were scrubbed in a speculum cleaner with Cetylcide II solution (Cetylite Industries, Inc., Pennsauken, NJ). Groups 5 and 6 cones were soaked for 20 min in Cetylcide II and chlorhexidine gluconate 2% solutions, respectively. Using sterile technique and after 10–15 min drying time, the cones were swabbed in a consistent pattern, and samples were submitted for quantitative culture. Culture results showed no growth from cones soaked in Cetylcide II or chlorhexidine solutions. Two of the 10 cones wiped with alcohol, 3/10 cones wiped then rinsed with water, and 3/10 cones scrubbed with the speculum cleaner showed growth ofP. aeruginosa. All (10/10) cones in the control group showed heavy growth ofP. aeruginosa. These results show thatP. aeruginosacan survive on otoscope cones cleaned and disinfected by several commonly used methods. Further study is needed to determine practical and optimal cleaning and disinfection methods for otoscope cones.
Patch testing of experimentally sensitized beagle dogs: development of a model for skin lesions of atopic dermatitis
Authors: Olivry Thierry , Deangelo Kristin B. , Dunston Stanley M. , Clarke Katie B. , Mccall Catherine A. 
Published: March 2006

AbstractIn humans with atopic dermatitis (AD), the epicutaneous application of allergens (atopy patch tests or APT) to which the patients are sensitized often results in the development of inflammation resembling that of spontaneous skin lesions. Dogs are affected with a natural homologue of human AD, but information on the induction of positive patch testing reactions is limited. The objectives of this pilot study were to determine the nature and cellular dynamics of inflammation occurring after APT in dogs hypersensitive to house dust mite and flea allergens. Laboratory Beagles were sensitized experimentally to Dermatophagoides farinae house dust mites (two dogs), Ctenocephalides felis flea saliva (one dog) or both (two dogs). Two other dogs served as nonsensitized controls. Both allergens and saline were applied epicutaneously. Macroscopic evaluations and skin biopsies were performed at 4, 24, 48 and 96 h after starting allergenic challenge. Biopsies were evaluated histologically and immunohistochemically with a panel of monoclonal antibodies specific for canine leucocyte antigens. Positive macroscopic reactions consisted of erythema, oedema and induration, and they occurred between 24 and 96 h after allergen application. Macroscopic and microscopic APT reactions developed only whenever serum IgE was present against tested allergens. Microscopically, positive APT was associated with epidermal hyperplasia, Langerhans’ cell hyperplasia, and eosinophil and lymphocyte epidermotropism. Dermal inflammation was mixed and arranged in a superficial perivascular to interstitial pattern. Numerous IgE+‐CD1+ dendritic cells and gamma‐delta T‐lymphocytes were observed. Macroscopically and microscopically, APT reactions in these experimentally sensitized animals resembled those seen in lesional biopsy specimens of dogs and humans with spontaneous AD. Therefore, APT in hypersensitive dogs provides a relevant experimental model to investigate the pathogenesis and treatment of both canine and human AD skin lesions.
Ciprofloxacin as a representative of disk diffusionin vitrosusceptibility of enrofloxacin for bacterial organisms from the middle‐ear tissue of dogs with end‐stage otitis externa
Authors: Cole Lynette K. , Kwochka Kenneth W. , Hillier Andrew , Kowalski Joseph J. , Smeak Daniel D. , Kelbick Nicole T 
Published: March 2006

AbstractThe purposes of this study were to determine whether ciprofloxacin disk diffusion susceptibility test (DDT) results could be used to assess thein vitrosusceptibility of otic bacterial organisms to enrofloxacin and to determine the effect of concurrent enrofloxacin administration on the DDT results for enrofloxacin and ciprofloxacin. Thirty dogs with end‐stage otitis externa undergoing unilateral total ear canal ablation were enrolled. The dogs were randomized to one of four enrofloxacin‐treatment groups or to the control group. Each dog in the treatment groups received two intravenous doses of enrofloxacin prior to surgical removal of the middle‐ear tissue while the control group did not receive any enrofloxacin. One dog was excluded from the study as no middle‐ear tissue was removed during surgery. Twenty‐four dogs were in the enrofloxacin‐treatment groups and five dogs were in the control group. In 12 of 29 dogs (41.4%), 14 of 82 (17.1%) of bacteria had discrepancies in DDT results for enrofloxacin and ciprofloxacin. Discrepancies between the control group and treatment groups were not significantly different even though the percentage of discrepancies for the combined treatment group was 19.4% compared to 6.7% for the control group. In this study, ciprofloxacin DDT results were not an accurate indicator of thein vitrosusceptibility of enrofloxacin for bacteria isolated from the middle‐ear tissue of dogs with end‐stage otitis.
Cellular and cytokine kinetics after epicutaneous allergen challenge (atopy patch testing) with house dust mites in high‐IgE beagles
Authors: Marsella Rosanna , Olivry Thierry , Maeda Sadatoshi 
Published: March 2006

AbstractThe cellular and cytokine dynamics of reactions triggered by atopy patch testing with house dust mites were studied in six high‐IgE beagles. Sites were scored and biopsied at 6, 24, 48, and 96 h, and samples were processed for histopathology, immunohistochemistry, and polymerase chain reaction (PCR).All dogs developed positive reactions at some point in time. Mean clinical scores were significantly higher than baseline at 24, 48, and 96 h. Clinically, one of six dogs had a positive reaction at 6 h; two of six reacted at 24 and 48 h, and five of six at 96 h.Histologically, superficial perivascular mononuclear and granulocytic dermatitis developed (5/6) after 6 h, and progressed in severity at 24 h (6/6). Additionally, at 48 h epidermal spongiosis, hyperplasia and pustules developed (5/6), and were marked at 96 h (6/6). At and beyond 6 h, progressive CD1c‐positive epidermal Langerhans cell hyperplasia with cluster formation and dermal dendritic cell infiltration was noted. Cutaneous infiltration of CD3‐positive T lymphocytes with epidermal clusters developed over time.mRNA expression for the cytokines gamma‐interferon (γ‐IFN), interleukin‐6 (IL‐6), IL‐12p35, IL‐13, IL‐18, and thymus and activation regulated chemokine (TARC) exhibited significant increases during the challenge compared to baseline, but there was no appreciable alteration in expression for tumour necrosis factor‐alpha (TNF‐α), IL‐12p40, IL‐10, regulated on activation normal T‐cell expressed and secreted (RANTES), IL‐5, IL‐2, IL‐4, and IL‐8. No correlation was detected between clinical scores and cytokines. It is concluded that IL‐6 plays a role in early reactions followed by an increase of TARC and IL‐13, while IL‐18 progressively increases in later reactions.
Quality of life after organ transplantation in type 1 diabetics with end‐stage renal disease
Authors: Sureshkumar Kalathil K , Patel Bhavesh M , Markatos Angelo , Nghiem Dai D , Marcus Richard J 
Published: March 2006

Abstract: Quality of life (QOL) should be an important consideration while choosing therapeutic options for patients with type 1 diabetes mellitus (DM) and end‐stage renal disease (ESRD) including dialysis, cadaver (CKT) or living kidney transplant (LKT) or simultaneous pancreas–kidney (SPK) transplant.Methods: QOL was assessed in four groups of patients with history of type 1 DM and ESRD: recipients of SPK (n = 43), CKT (n = 43), LKT (n = 11) and wait listed (WL) patients (n = 23). Diabetes Quality of Life (DQOL), Short Form‐36 (SF‐36) and Quality of Well‐Being (QWB) questionnaires were utilized. A subset of SPK (n = 19) and CKT (n = 12) recipients underwent longitudinal QOL evaluation.Results: On DQOL questionnaire, SPK group had better satisfaction subscore compared with CKT (1.8 ± 0.5 vs. 2.2 ± 0.6, p < 0.01) LKT (1.8 ± 0.5 vs. 2.4 ± 0.7, p < 0.05) and WL (1.8 ± 0.5 vs. 2.6 ± 0.6, p < 0.001) groups and better impact subscore compared with CKT (1.7 ± 0.6 vs. 2.1 ± 0.6, p < 0.05) and WL (1.7 ± 0.6 vs. 2.3 ± 0.6, p < 0.01) groups. There were no significant differences on physical/mental composite scores of SF‐36. QWB score was better in SPK group vs. WL group (0.62 ± 0.11 vs. 0.55 ± 0.04, p < 0.05). Longitudinal decline in satisfaction (2.3 ± 0.5 vs. 2.6 ± 0.9, p = 0.058) and impact (2.0 ± 0.5 vs. 2.2 ± 0.5, p = 0.019) subscores of DQOL were noted in CKT group. There were no significant changes in the composite scores of SF‐36 in both groups. QWB scores declined in the CKT group (0.67 ± 0.10 vs. 0.61 ± 0.05, p = 0.01).Conclusion: QOL was better in type 1 diabetics with ESRD following transplantation when compared with remaining on WL. SPK transplantation had significant positive effect on diabetes‐related QOL which was sustained longitudinally but it was difficult to show an overall improvement in general QOL.
Evidence for a robust sex‐specific trade‐off between cold resistance and starvation resistance in Drosophila melanogaster
Authors: HOFFMANN A. A. , HALLAS R. , ANDERSON A. R. , TELONIS‐SCOTT M. 
Published: March 2006

AbstractIn insects changes in lipid metabolism may underlie a trade‐off between cold resistance and starvation resistance. To test this we examined correlated responses in independent sets of Drosophila melanogaster lines selected for increased cold resistance and increased starvation resistance. The starvation lines showed correlated patterns found in other D. melanogaster populations selected for this trait, including higher lipid levels and increased resistance to desiccation, although the selected lines did not show a longer development time as found in some other studies. Consistent with the trade‐off hypothesis, selected lines with increased starvation resistance showed decreased resistance to a cold stress as measured by mortality, whereas selected lines with increased cold resistance showed a decrease in starvation resistance. To counter the possibility of inadvertent selection accounting for these patterns, selected and control lines from both selection regimes were crossed to form mass bred populations, which were left for four generations prior to establishing isofemale lines. By scoring starvation and cold resistance in these lines derived from both sets of selection regimes, we confirmed the negative association between resistance to these stresses in females but not in males. Potential implications of this trade‐off for surviving cold conditions when food resources are limiting are discussed.
Proximate causes of adaptive growth rates: growth efficiency variation among latitudinal populations of Rana temporaria
Authors: LINDGREN B. , LAURILA A. 
Published: March 2006

AbstractIn ectothermic organisms, declining season length and lower temperature towards higher latitudes often select for latitudinal variation in growth and development. However, the energetic mechanisms underlying this adaptive variation are largely unknown. We investigated growth, food intake and growth efficiency of Rana temporaria tadpoles from eight populations along a 1500 km latitudinal gradient across Sweden. To gain an insight into the mechanisms of adaptation at organ level, we also examined variation in tadpole gut length. The tadpoles were raised at two temperatures (16 and 20 °C) in a laboratory common garden experiment. We found increased growth rate towards higher latitudes, regardless of temperature treatment. This increase in growth was not because of a higher food intake rate, but populations from higher latitudes had higher growth efficiency, i.e. they were more efficient at converting ingested food into body mass. Low temperature reduced growth efficiency most strongly in southern populations. Relative gut length increased with latitude, and tadpoles at low temperature tended to have longer guts. However, variation in gut length was not the sole adaptive explanation for increased growth efficiency as latitude and body length still explained significant amounts of variation in growth efficiency. Hence, additional energetic adaptations are probably involved in growth efficiency variation along the latitudinal gradient.
Altitudinal variation for stress resistance traits and thermal adaptation in adult Drosophila buzzatii from the New World
Authors: SØRENSEN J. G. , NORRY F. M. , SCANNAPIECO A. C. , LOESCHCKE V. 
Published: March 2006

AbstractMultiple stress resistance traits were investigated in the cactophilic fly Drosophila buzzatii. Adults from seven populations derived from North‐Western Argentina were compared with respect to traits relevant for thermal stress resistance and for resistance to other forms of environmental stress. The populations were collected along an altitudinal gradient spanning more than 2000 m in height, showing large climatic differences. The results suggest that knock‐down resistance to heat stress, desiccation resistance and Hsp70 expression at a relatively severe stressful temperature best reflect thermal adaptation in this species. Furthermore, cold resistance seemed to be of less importance than heat resistance, at least for the adult life stage, in these populations. Clinal variation in thermal resistance traits over short geographical distances suggests relatively strong adaptive differentiation of the populations. This study provides the first evidence for altitudinal differentiation in stress‐related traits, and suggests that Hsp70 expression level can be related to altitudinal clines of heat‐stress resistance.
ADH enzyme activity and Adh gene expression in Drosophila melanogaster lines differentially selected for increased alcohol tolerance
Authors: MALHERBE Y. , KAMPING A. , VAN DELDEN W. , VAN DE ZANDE L. 
Published: March 2006

AbstractIn Drosophila melanogaster, alcohol dehydrogenase (ADH) activity is essential for ethanol tolerance, but its role may not be restricted to alcohol metabolism alone. Here we describe ADH activity and Adh expression level upon selection for increased alcohol tolerance in different life‐stages of D. melanogaster lines with two distinct Adh genotypes: AdhFF and AdhSS. We demonstrate a positive within genotype response for increased alcohol tolerance. Life‐stage dependent selection was observed in larvae only. A slight constitutive increase in adult ADH activity for all selection regimes and genotypes was observed, that was not paralleled by Adh expression. Larval Adh expression showed a constitutive increase, that was not reflected in ADH activity. Upon exposure to environmental ethanol, sex, selection regime life stage and genotype appear to have differential effects. Increased ADH activity accompanies increased ethanol tolerance in D. melanogaster but this increase is not paralleled by expression of the Adh gene.
The heritability of inducible defenses in tadpoles
Authors: RELYEA R. A. 
Published: March 2006

AbstractThe evolution of plastic traits requires phenotypic trade‐offs and heritable traits, yet the latter requirement has received little attention, especially for predator‐induced traits. Using a half‐sib design, I examined the narrow‐sense heritability of predator‐induced behaviour, morphology, and life history in larval wood frogs (Rana sylvatica). Many of the traits had significant additive genetic variation in predator (caged Anax longipes) and no‐predator environments. Whereas most traits had moderate to high heritability across environments, tail depth exhibited high heritability with predators but low heritability without predators. In addition, several traits had significant heritability for plasticity, suggesting a potential for selection to act on plasticity per se. Genetic correlations confirmed known phenotypic relationships across environments and identified novel relationships within each environment. This appears to be the first investigation of narrow‐sense heritabilities for predator‐induced traits and confirms that inducible traits previously shown to be under selection also have a genetic basis and should be capable of exhibiting evolutionary responses.