bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of an ionic detergent on the natively unfolded β‐dystroglycan ectodomain and on its interaction with α‐dystroglycan
Authors: Bozzi Manuela , Di Stasio Enrico , Cicero Daniel O. , Giardina Bruno , Paci Maurizio , Brancaccio Andrea
Published: August 2004

Dystroglycan (DG) is an adhesion complex, expressed in a wide variety of tissues, formed by an extracellular and a transmembrane subunit, α‐DG and β‐DG, respectively, interacting noncovalently. Recently, we have shown that the recombinant ectodomain of β‐DG, β‐DG(654–750), behaves as a natively unfolded protein, as it is able to bind the C‐terminal domain of α‐DG, while not displaying a defined structural organization. We monitored the effect of a commonly used denaturing agent, the anionic detergent sodium dodecylsulphate (SDS), on β‐DG(654–750) using a number of biophysical techniques. Very low concentrations of SDS (≤2 mM) affect both tryptophan fluorescence and circular dichroism of β‐DG, and significantly perturb the interaction with the α‐DG subunit as shown by solid‐phase binding assays and fluorescence titrations in solution. This result confirms, as recently proposed for natively unfolded proteins, that β‐DG(654–750) exists in a native state, which is crucial to fulfill its biological function. Two‐dimensional NMR analysis shows that SDS does not induce any evident conformational rearrangement within the ectodomain of β‐DG. Its first 70 amino acids, which show a lower degree of mobility, interact with the detergent, but this does not change the amount of secondary structure, whereas the highly flexible and mobile C‐terminal region of β‐DG(654–750) remains largely unaffected, even at a very high SDS concentration (up to 50 mM). Our data indicate that SDS can be used as a useful tool for investigating natively unfolded proteins, and confirm that the β‐DG ectodomain is an interesting model system.
Hexa‐histidin tag position influences disulfide structure but not binding behavior of in vitro folded N‐terminal domain of rat corticotropin‐releasing factor receptor type 2a
Authors: Klose Jana , Wendt Norbert , Kubald Sybille , Krause Eberhard , Fechner Klaus , Beyermann Michael , Bienert Michael , Rudolph Rainer , Rothemund Sven
Published: August 2004

The oxidative folding, particularly the arrangement of disulfide bonds of recombinant extracellular N‐terminal domains of the corticotropin‐releasing factor receptor type 2a bearing five cysteines (C2 to C6), was investigated. Depending on the position of a His‐tag, two types of disulfide patterns were found. In the case of an N‐terminal His‐tag, the disulfide bonds C2–C3 and C4–C6 were found, leaving C5 free, whereas the C‐terminal position of the His‐tag led to the disulfide pattern C2–C5 and C4–C6, and leaving C3 free. The latter pattern is consistent with the disulfide arrangement of the extracellular N‐terminal domain of the corticotropin‐releasing factor (CRF) receptor type 1, which has six cysteines (C1 to C6) and in which C1 is paired with C3. However, binding data of the two differently disulfide‐bridged domains show no significant differences in binding affinities to selected ligands, indicating the importance of the C‐terminal portion of the N‐terminal receptor domains, particularly the disulfide bond C4–C6 for ligand binding.
SPATIAL MARKETS FOR CONSULTANCY TO SMEs
Authors: BENNETT ROBERT J. , SMITH COLIN
Published: August 2004

This paper demonstrates the existence of both localised and national spatial markets for consultancy in Britain. A large survey sample of 1,208 client‐advisor links whose locations are geo‐coded is investigated using GIS software. It is expected from previous literature that search and selection effects, and the transaction costs of interaction at different distances, will influence the selection of consultants by clients. The paper shows that most client‐advisor relationships are geographically close: 61.3 per cent of links are less than 20 km in distance. But there is also a national market whereby 21.9 per cent of consultants are over 100 km and 7.9 per cent are over 200 km from the client. From these patterns, the maximum reach of market areas for different business centres can be estimated. This varies by type of consultancy assignment and size of business centre. The market area is only 30–40 km for consultancy on marketing and sales, and finance and taxation, which are sourced chiefly from local small business centres. For consultancy on business strategy and organisation, product design and quality and training/HR, regional centres and London play a more important role. The paper demonstrates something of a hierarchical structure of consultancy assignments and their spatial markets that is similar to that in retailing.
Nothing or Someone? Some thoughts on Identity, Diversity and Education
Authors: McCreery Elaine
Published: August 2004

A children's story about a cuddly toy, forgotten and left behind in the attic, serves as the vehicle for Elaine McCreery's reflections on identity and diversity in the context of education. For both children and teachers, the sense of who we are – especially when all around us (and within us) is changing at an alarming rate – is supremely important. Ethnic and racial diversity, migration and acculturation have powerful consequences for identity, as have the changing religious and normative orientations of post‐modernity. For teachers (and teachers‐in‐training), learning to juggle the multiple realities and conflicting expectations of a diverse society is an immense challenge. The effective teacher is not unlike the stand‐up comedian, ‘reading’ the audience and adapting to the local scene, but with much more at stake: the moral and spiritual well‐being of those s/he teaches.
Empathy, Interaction and Caring: Teachers' Roles in a Constrained Environment
Authors: Cooper Bridget
Published: August 2004

This paper describes some of the key findings from a recently completed PhD, which examined the role of empathy in teacher–pupil relationships and its relevance to moral modelling. The project collected data through interviews and classroom observations and used grounded methodology theory for the analysis. The literature considers the latest research in neuroscience and the significance of emotions in moral decision making alongside older psychological research on affect and empathy in learning.

Despite an overwhelming desire to support, care for and relate deeply to pupils, teachers were continually constrained by the conditions in which they worked. Time was stolen from them by the nature of the current education system; the fragmented and rigid curriculum; the time poor nature of their working conditions; the bureaucracy of modern education and the large numbers of pupils and low frequency of contact. The moral model available for students becomes degraded and needs remain unmet. Teachers are obliged to show lack of care towards individuals, the reverse of what they believe to be necessary and what their pupils want and need.
Linking Product Development Outcomes to Market Valuation of the Firm: The Case of the U.S. Pharmaceutical Industry*
Authors: Sharma Anurag , Lacey Nelson
Published: August 2004

The purpose of this research was to examine empirically the effects of new product development outcomes on overall firm performance. To do so, first product development and finance literature were connected to develop three testable hypotheses. Next, an event study was conducted in order to explore whether the changes in the stock market valuation of firms are influenced by the outcomes of efforts to develop new products. The pharmaceutical industry was chosen as the empirical context for the present study's analysis largely because the gate‐keeping role played by the Food and Drug Administration (FDA) provides a specific event date on which to focus the event study methodology. As such, this study's events were dates of public announcements of the FDA decisions to approve or to reject the New Drug Applications submitted by the sponsoring firms.

Consistent with the efficient market hypothesis, this study's results show that market valuations are responsive strongly and cleanly to the success or failure of new product development efforts. Hence, one of this study's key results suggests that financial markets may be attuned sharply to product development outcomes in publicly traded firms. This study also finds that financial market losses from product development failures were much larger in magnitude than financial market gains from product development successes—indicating an asymmetry in the response of financial markets to the success and failure of new product development efforts. Hence, another implication of this study's results is that managers should factor in a substantial risk premium when considering substantial new development projects. The present study's results also imply that managers should refrain from hyping new products and perhaps even should restrain the enthusiasm that the financial community may build before the product fully is developed. The effect on firm value is severe when expectations about an anticipated new product are not fulfilled. Managers in effect should take care to build reasonable and realistic expectations about potential new products.
Book Reviews
Authors: Smith Preston G.
Published: August 2004

Books reviewed in this issue:

How Customers Think: Essential Insights in the Mind of the Market

Value Sweep: Mapping Corporate Growth Opportunities

Innovation Management in the Knowledge Economy

Innovating at the Edge: How Organizations Evolve and Embed Innovation Capability
Retinal Embolization of Bicuspid Aortic Valve Calcification
Authors: Palmiero Pasquale , Maiello Maria , Nanda Navin C.
Published: August 2004

We report the case of a 36‐year‐old man with calcified bicuspid aorta. Aortic disease was diagnosed after retinal embolism, which caused loss of vision affecting the left eye. Doppler examination did not identify carotid stenosis. Transthoracic echocardiography showed thickness and calcification of two leaflets, moderate aortic regurgitation, high normal left ventricular diastolic dimensions, and high normal interventricular septum thickness. Parasternal long‐axis view in the systolic frame showed dilated left ventricular outflow tract, dilated ascending aorta, and calcification and thickening of aortic leaflets, causing an echo‐lucent area, in the diastolic frame. It also showed the eccentric position of the closed valve leaflets, short axis in the diastolic frame, and the absence of the typical “Y” letter sign, tracked by the three leaflets (septal, right coronary, and left coronary) in the normal tricuspid aortic valve. On long‐axis parasternal acquisition, we note high normal interventricular septum thickness and high normal diastolic diameter. Color Doppler analysis from the apical five‐chamber view showed aortic regurgitation; regurgitant jet area was about 44% of the outflow tract, so aortic regurgitation was classified as moderate. Pulsed Doppler showed a high normal value of peak aortic velocity. Transesophageal echocardiography was performed, but no further findings were identified. We think that the likely retinal embolism sources were the aortic calcified leaflets, even if the aortic valve was not stenotic and with no signs of endocarditis. However, because we cannot exclude other potential causes, we put the patient on anticoagulant therapy. Furthermore, aortic valve replacement was not advised.
Hypertrophic Cardiomyopathy: A Case of Symptomatic Japanese Type Apical Hypertrophic Cardiomyopathy
Authors: Meriç Murat , Arslandağ Muharrem , Yazici Mustafa , Sağkan Olcay
Published: August 2004

A 61‐year‐old male patient was hospitalized due to the exertional angina pectoris. A diagnosis of apical hypertrophic cardiomyopathy was made by ECG (electrocardiography), echocardiographic, and coronary angiographic findings. This case was reported and related literature was reviewed because of its similarity to Japanese type apical hypertrophic cardiomyopathy (AHCMP) cases rarely seen outside Asia.
Aortic Ectasia with Hemiazygos Vein Dilatation: A Mimicker of Aortic Dissection
Authors: Leggio Massimo , Sgorbini Luca , Cicone Emilio , Leggio Francesco
Published: August 2004

Infrahepatic interruption of the inferior vena cava (IVC) is a rare but well‐documented finding. In this condition, the IVC between renal and hepatic vein is absent and the hepatic veins directly empty into the right atrium; because of the enlargement of the azygos–hemiazygos vein system, this condition could mimic aortic pathology. We will describe a case of aortic arch enlargement with dilatation of hemiazygos vein, which was initially misdiagnosed by two‐dimensional transesophageal echocardiography (TEE) as aortic dissection. TEE‐Doppler identified the real condition, which was confirmed by computed tomography.
Extremely Rapid Formation of Mitral Valve Ring Abscess in Infective Endocarditis
Authors: Shrestha Balaram , Ishizuka Naoko , Tanimoto Kyomi , Kawai Akihiko , Kurosawa Hiromi , Kasanuki Hiroshi
Published: August 2004

A patient with infective endocarditis (IE) due to methicillin‐resistant staphylococcus aureus (MRSA) was found to have conversion of the hypoechoic region of the posterior mitral valve ring apparatus into a clearly delineated echolucent space by repeating transthoracic echocardiography at an interval of 1 week. Color Doppler showed features of blood entry into this space. Abscess formation in IE due to MRSA may be quick and repeated echocardiography may help detect the complications of IE. Semiurgent mitral valve plasty was performed for the associated prolapse of the posterior mitral leaflet using a hand‐made, rolled, twisted autologous pericardial ring.
Precordial Abscess Inducing Chest Pain 20 Years After Surgical Repair of a Pentalogy of Fallot
Authors: Aschwanden Evelyne , Bodenmann Patrick , Schlueter Léo , Fivat‐Arbane Malika , Hurni Michel , Qanadli Salah Dine , Jaussi Andres
Published: August 2004

A 25‐year‐old male asylum‐seeker presented with chest pain, exertional dyspnea, and orthopnea 20 years after the surgical repair of a pentalogy of Fallot. An extracardiac mass compressing the right ventricle was subsequently detected and surgical decompression was performed to relieve the resulting right intraventricular hypertension. At operation, the mass proved to be a coagulase‐negative, staphylococcal abscess. In addition, the removal of the mass unmasked a previously nonrecognized pulmonary outflow stenosis that required balloon dilatation and β‐blocker therapy. While infections are known to occur after sternotomy, the formation of an abscess in the anterior mediastinum several years after the intervention appears to be exceptional; this diagnosis came to mind only after the more common complications had been considered, e.g., pseudoaneurysm or pericardial hematoma. To our knowledge, this is the first report of an abscess in the anterior mediastinum that had probably formed over many years following a sternotomy, compressed the right ventricle and masked a pulmonary stenosis.
Myocardial Performance Index in Evaluation of Acute Right Ventricular Myocardial Infarction
Authors: Chockalingam Anand , Gnanavelu G. , Alagesan R. , Subramaniam T.
Published: August 2004

The goal of this study was to evaluate the role of Doppler time interval‐derived myocardial performance index (MPI) in the setting of acute right ventricular myocardial infarction (RVMI). Inferior myocardial infarction is accompanied by RVMI in over a third of cases. We do not have easily applicable noninvasive tools for reliably quantifying the right ventricular (RV) dysfunction in RVMI and to serially follow alterations. Clinical and echocardiography data of all acute inferior myocardial infarction (IMI) admissions (n = 135) to our referral teaching institute were prospectively collected for the study. After exclusions, study group comprised of 36 patients with RVMI diagnosed by ≥1 mm ST segment elevation in V3R‐V5R of right‐sided ECG and 63 patients without RVMI constituted the control group. All patients underwent echocardiography within 24 hours of admission. Normal range of MPI for our laboratory was estimated from 50 age‐matched healthy subjects. RV MPI was elevated to a mean of 0.53 ± 0.22 in RVMI (Normal MPI 0.20 ± 0.05, P‐value < 0.001). IMI without RVMI did not elevate MPI significantly (0.21 ± 0.17, P‐value NS). Repeat MPI estimation in 11 RVMI (7 thrombolyzed) patients after 5 days showed dramatic reduction (0.23 ± 0.12, P‐value < 0.001). This reduction was noted irrespective of thrombolysis. RV MPI ≥ 0.30 has high sensitivity (82%) and specificity (95%) for the diagnosis of RVMI in the presence of acute IMI. MPI can reliably diagnose RV infarction. It can be used to quantify right ventricular dysfunction and assess acute improvements in RV function.
Pneumatic balloon dilatation in achalasia: a prospective comparison of safety and efficacy with different balloon diameters
Authors: Mikaeli J. , Bishehsari F. , Montazeri G. , Yaghoobi M. , Malekzadeh R.
Published: August 2004

Background : Pneumatic dilatation is considered to be the first line therapy for achalasia, but long‐term outcome studies are scarce and limited by their retrospective design. There is also no consensus on the optimal method for performing pneumatic dilation as regard to balloon diameter, amount and the rate inflation pressure.

Aim : To address these questions in a large long‐term prospective study.

Methods : Over a period of 10 years 262 achalasia patients referred to our centre were enrolled. All patients underwent a pre‐treatment clinical evaluation and were followed every 6 months. The first 62 patients (group A) underwent dilatation with initial use of a 35 mm balloon with inflation pressure of 10 psi in 10 seconds (s). In group B (200 patients) we initially used a 30 mm balloon with inflation pressure of 10 psi in 30 s. Dilatation was repeated with incrementally larger balloons (35 and 40 mm) in case of relapse. We used rigiflex balloon and maintained pressure for 60 s after inflation in both groups.

Results : Three perforations occurred in group A whereas no perforation took place in Group B. The cumulative proportional remission rate with single dilatation in groups A and B decreased from 83 and 75% in 6 months to 60 and 57% after 30 months of therapy respectively, the differences did not reach statistical significance. In patients who had undergone further dilatations the probability of remaining in remission at 1 year after the first and the second dilatation was 38 and 88% in group A, 20 and 89% in group B respectively. The probability of remaining in remission for 2 years increased from 20% after the first dilatation to 70% after the second dilatation.

Conclusion : Graded pneumatic balloon dilatation with 30 mm diameter and slower rate of balloon inflation is an effective and safe initial method of therapy for achalasia. The duration of remission can be extended by repeated dilatation with larger size balloon.
Identifying response to acid suppressive therapy in functional dyspepsia using a random starting day trial – is gastro‐oesophageal reflux important?
Authors: Madsen L. G. , Wallin L. , Bytzer P.
Published: August 2004

Background : Single subject trials offer an alternative approach to identify and characterize responders to a specific treatment.

Aim : To test a new single subject trials design, called random starting day trial, to identify acid‐related symptoms in dyspepsia.

Methods : A total of 119 patients with functional dyspepsia entered a 12‐day, double‐blind random starting day trial. All patients started on placebo and switched to omeprazole 80 mg/day at a randomized and blinded day between day 5 and day 9, with active treatment continuing for the rest of the trial. Based on changes of a daily symptom score, response was defined as a sustained ≥50% reduction of symptoms within 3 days of active treatment.

Results : Thirteen of 119 patients (11%) were classified as spontaneous responders because of complete symptom relief before switching to omeprazole. Of the remaining 106 patients, 15 (15.6%) were classified as responders. Five of six (83%) responders compared with 28 of 53 (53%) non‐responders had pathological reflux. Multivariate testing identified symptoms suggestive of gastro‐oesophageal reflux predictive of response.

Conclusions : The random starting day trial design could identify a subset of dyspeptic patients with a uniform symptomatic response to acid‐suppressive therapy. Response seems to be associated with gastro‐oesophageal reflux. The random starting day trial needs to be further validated to be considered as a reliable instrument in clinical research.
A rapid immunochromatographic assay for Helicobacter pylori in stool before and after treatment
Authors: Gatta L. , Perna F. , Ricci C. , Osborn J. F. , Tampieri A. , Bernabucci V. , Miglioli M. , Vaira D.
Published: August 2004

Background : Current guidelines recommend non‐invasive testing and treatment of young dyspeptic patients without alarm symptoms.

Aim : To evaluate the accuracy of a new rapid immunochromatographic stool test to diagnose Helicobacter pylori infection before and after treatment compared with a gold standard.

Methods : Prospective, single‐blind study, performed in a tertiary care hospital. A total of 303 consecutive dyspeptic patients underwent endoscopy with multiple biopsies. Infected patients were offered a treatment and invited to come back 4–6 weeks after the end of therapy to repeat the endoscopy. Patients were also asked to provide a stool sample before and after therapy.

Results : About 149 patients were H. pylori infected. The sensitivity and specificity before treatment were 91.3 and 93.5%; after treatment 92 and 100%. The likelihood ratios were robust enough to produce significant changes from pretest to post‐test probability both in pre‐treatment (LR+ = 14, LR− = 0.093) and post‐treatment (LR+ = 19.6, LR− = 0.095).

Conclusions : The novel immunochromatographic stool test is fast, easy to perform and provides good differentiation between positive and negative results. It might become a rapid near patients test easily performed in the doctor office.
Pathogenicity of Stagonospora nodorum requires malate synthase
Authors: Solomon Peter S. , Lee Robert C. , Wilson T. J. Greer , Oliver Richard P.
Published: August 2004

A gene encoding malate synthase, a key enzyme of the glyoxylate cycle, has been cloned and characterized in the necrotrophic wheat pathogen Stagonospora nodorum. Expression studies of Mls1 showed high levels of transcript in ungerminated spores whereas malate synthase enzyme activities were low. Expression studies in planta found that Mls1 transcript levels decreased ≈ 10‐fold upon germination before slowly increasing throughout the remainder of the infection. To characterize Mls1 further, the gene was disrupted in S. nodorum by homologous recombination. In the absence of any supplied carbon source, the mls1 spores were unable to germinate and consequently the mutants were non‐pathogenic. Germination and pathogenicity could be restored by the addition of either glucose or sucrose, implying that S. nodorum is reliant upon the catabolism of lipids for infection. Furthermore, analysis of lipid bodies in the mutant strain indicated that lipid mobilization and, consequently, peroxisomal β‐oxidation of fatty acids is delayed or inhibited by the disruption of the glyoxylate cycle. This study has demonstrated for the first time in a fungal phytopathogen the requirement of malate synthase for pathogenicity, suggesting that gluconeogenesis is both dependent on the glyoxylate cycle and required for infection.
Pseudomonas aeruginosa attachment and biofilm development in dynamic environments
Authors: Ramsey Matthew M. , Whiteley Marvin
Published: August 2004

Biofilm formation by Pseudomonas aeruginosa is hypothesized to follow a developmental pattern initiated by attachment to a surface followed by microcolony formation and mature biofilm development. Swimming and twitching motility are important for attachment and biofilm development in P. aeruginosa. However, it is clear that many P. aeruginosa strains lacking swimming motility exist as biofilms in the lungs of cystic fibrosis patients. Consequently, we have developed a dynamic attachment assay to identify motility‐independent attachment‐defective mutants. Using transposon mutagenesis, we identified 14 novel dynamic attachment‐deficient (dad) mutants including four mutants specific to dynamic assay conditions (dad specific). Two of the dad‐specific mutants contain insertions in genes involved in sensing and responding to external stimuli, implying a significant impact of external factors on the biofilm developmental pathway. Observations of initial attachment and long‐term biofilm formation characterized our dad mutants into two distinct classes: biofilm delayed and biofilm impaired. Biofilm‐delayed mutants form wild‐type biofilms but are delayed at least 24 h compared with the wild type, whereas biofilm‐impaired mutants never form wild‐type biofilms in our assays. We propose a dynamic model for attachment and biofilm formation in P. aeruginosa including these two classes.
A novel extracellular phospholipase C of Pseudomonas aeruginosa is required for phospholipid chemotaxis
Authors: Barker Adam P. , Vasil Adriana I. , Filloux Alain , Ball Genevieve , Wilderman Paula J. , Vasil Michael L.
Published: August 2004

Pseudomonas aeruginosa and other bacterial pathogens express one or more homologous extracellular phospholipases C (PLC) that are secreted through the inner membrane via the twin arginine translocase (TAT) pathway. Analysis of TAT mutants of P. aeruginosa uncovered a previously unidentified extracellular PLC that is secreted via the Sec pathway (PlcB). Whereas all presently known PLCs of P. aeruginosa (PlcH, PlcN and PlcB) hydrolyse phosphatidylcholine (PC), only PlcB is active on phosphatidylethanolamine (PE). plcB candidates were identified based on deductions made from bioinformatics data and extant DNA microarray data. Among these candidates, a gene (PA0026) required for the expression of an extracellular PE‐PLC was identified. The protein encoded by PA0026 has limited, but significant similarity, over a short region (∼60aa of 328), to a class of zinc‐dependent prokaryotic PLCs. A conserved His residue of PlcB (His216) that is required for coordinate binding of zinc in this class of PLCs was mutated. Analysis of this mutant established that the protein encoded by PA0026 is PlcB. Three in‐dependent recently published reports indicate that homoserine lactone‐mediated quorum sensing regulates the expression of PA0026 (i.e. plcB). PlcB, but not PlcH or PlcN, is required for directed twitching motility up a gradient of certain kinds of phospholipids. This response shows specificity for the fatty acid moiety of the phospholipid.
Silencing the ap65 gene reduces adherence to vaginal epithelial cells by Trichomonas vaginalis
Authors: Mundodi V. , Kucknoor A. S. , Klumpp D. J. , Chang T. ‐H. , Alderete J. F.
Published: August 2004

Host parasitism by Trichomonas vaginalis is complex and in part mediated by adherence to vaginal epithelial cells (VECs). Four trichomonad surface proteins bind VECs as adhesins, and AP65 is a major adhesin with sequence identity to an enzyme of the hydrogenosome organelle that is involved in energy generation. In order to perform genetic analysis and assess the role of AP65 in T. vaginalis adherence, we silenced expression of ap65 using antisense RNA. The gene for ap65 was inserted into the vector pBS‐neo in sense and antisense orientations to generate plasmids pBS‐neoS (S) and pBS‐neoAS (AS), respectively. Trichomonads were then transfected with S and AS plasmids for selection of stable transfectants using Geneticin, and the presence of plasmid in transfectants was confirmed by polymerase chain reaction of the neo gene. Reverse transcription polymerase chain reaction and Northern blot analysis showed decreased amounts of ap65 transcript in AS transfected parasites. Growth kinetics of the antisense‐transfected and wild type organisms were similar, suggesting that silencing AP65 did not affect overall energy generation for growth. Immunoblot analysis using monoclonal antibody (mAb) to AP65 of AS transfectants showed decreased amounts of AP65 when compared to wild type or S transfectants. Not unexpectedly, this corresponded to decreased amounts of AP65 bound to VECs in a functional ligand assay. Reduction in parasite surface expression of AP65 was related to lower levels of adherence to VECs by AS‐transfectants compared to control organisms. Antisense silencing of ap65 was not alleviated by growth of trichomonads in high iron, which up‐regulates transcription of ap65. Our work reaffirms the role for AP65 as an adhesin, and in addition, we demonstrate antisense RNA gene silencing in T. vaginalis to study the contribution of specific genes in pathogenesis.
A family of Candida cell surface haem‐binding proteins involved in haemin and haemoglobin‐iron utilization
Authors: Weissman Ziva , Kornitzer Daniel
Published: August 2004

The ability to acquire iron from host tissues is a major virulence factor of pathogenic microorganisms. Candida albicans is an important fungal pathogen, responsible for an increasing proportion of systemic infections. C. albicans, like many pathogenic bacteria, is able to utilize haemin and haemoglobin as iron sources. However, the molecular basis of this pathway in pathogenic fungi is unknown. Here, we identify a conserved family of plasma membrane‐anchored proteins as haem‐binding proteins that are involved in haem‐iron utilization. We isolated RBT51 as a gene that is sufficient by itself to confer to S. cerevisiae the ability to utilize haemoglobin iron. RBT51 is highly homologous to RBT5, which was previously identified as a gene negatively regulated by the transcriptional suppressor CaTup1. Rbt5 and Rbt51 are mannosylated proteins that carry the conserved CFEM domain. We find that RBT5 is strongly induced by starvation for iron, and that deletion of RBT5 is by itself sufficient to significantly reduce the ability of C. albicans to utilize haemin and haemoglobin as iron sources. Iron starvation‐inducible, antigenically cross‐reacting haem‐binding proteins are also present in other Candida species that are able to utilize haem‐iron, underscoring the conservation of this iron acquisition pathway among pathogenic fungi.
Plasmid DNA transfer in Mycobacterium smegmatis involves novel DNA rearrangements in the recipient, which can be exploited for molecular genetic studies
Authors: Wang Jun , Derbyshire Keith M.
Published: August 2004

The establishment of molecular genetic techniques is essential for development of new treatments for mycobacterial infections. To this end, we recently described a novel DNA transfer process that occurs in the model mycobacterial organism Mycobacterium smegmatis. This transfer system is most like conjugal DNA transfer in that it requires two viable parents, is DNAse resistant and occurs between distinct donor and recipient strains. Cis‐acting sequences called bom, which confer transferability, are distinct from the prototypical oriT sites of conjugative plasmids, as they occur at multiple locations in the chromosome and require RecA in the recipient to mediate plasmid recircularization. Here, we show that a plasmid containing two of these bom regions can undergo several fates in the recipient cell, each of which require recipient recombination functions. The products of plasmid transfer that we observed provide further insights toward a model for DNA transfer. Furthermore, we have taken advantage of the recombination events that occur in the recipient to develop simple procedures for capturing, or replacing specific segments of the recipient chromosome. To demonstrate the potential of the system, we describe the capture and deletion of 25 kb of the M. smegmatis chromosome, and targeted‐allele exchange of the recipient recB and recD genes. Using these transfer‐mediated rearrangements, we demonstrate that homology with the recipient chromosome and RecB, but not RecD, are essential for DNA transfer.
Secretion of proteins with dimerization capacity by the haemolysin type I transport system ofEscherichia coli
Authors: Fraile Sofía , Muñoz Amalia , De Lorenzo Víctor , Fernández Luis Angel
Published: August 2004

The tolerance of the haemolysin transport system (Hly) for exporting dimeric protein substrates to the supernatants ofEscherichia colicultures was examined. A strong dimerization domain (i.e. an amphipathic α‐helix capable of forming a leucine zipper in the yeast transcription factor GCN4) was inserted into an epitope‐tagged version of the 23 kDa C‐terminal secretion signal of haemolysin (EHlyA). The zipper‐containing polypeptide (ZEHlyA) was effectively secreted byE. colicells carrying the HlyBD transporter and accumulated in the culture media as a stable dimer as determined by gel filtration chromatography.In vivoprotein cross‐linking experiments and coexpression with a secretion‐deficient derivative of ZEHlyA indicated that leucine zipper‐dependent dimerization occurs following secretion. To test whether dimerization allows the correct folding of the secreted polypeptide, immunoglobulin VHH‐domains obtained from camel antibodies were fused to EHlyA and ZEHlyA. Functional dimerization of the ZEHlyA hybrid was anticipated to increase the apparent binding affinity (i.e. avidity) of the VHHmoiety, thus becoming an excellent reporter of correct protein folding and dimerization. Both VHH‐EHlyA and VHH‐ZEHlyA hybrids were quantitatively secreted and found in the extracellular medium as active monomers and dimers respectively. When compared with their monomeric counterparts, the dimeric VHH‐ZEHlyA molecules showed superior binding properties to their cognate antigen, with a 10‐fold increase in their avidity. These data reveal a non‐anticipated permissiveness of the Hly type I transport machinery for the secretion of substrates with dimerization capacity.
MicroReview: Small molecules that regulate lifespan: evidence for xenohormesis
Authors: Lamming Dudley W. , Wood Jason G. , Sinclair David A.
Published: August 2004

Barring genetic manipulation, the diet known as calorie restriction (CR) is currently the only way to slow down ageing in mammals. The fact that CR works on most species, even microorganisms, implies a conserved underlying mechanism. Recent findings in the yeast Saccharomyces cerevisiae indicate that CR extends lifespan because it is a mild biological stressor that activates Sir2, a key component of yeast longevity and the founding member of the sirtuin family of deacetylases. The sirtuin family appears to have first arisen in primordial eukaryotes, possibly to help them cope with adverse conditions. Today they are found in plants, yeast, and animals and may underlie the remarkable health benefits of CR. Interestingly, a class of polyphenolic molecules produced by plants in response to stress can activate the sirtuins from yeast and metazoans. At least in the case of yeast, these molecules greatly extend lifespan by mimicking CR. One explanation for this surprising observation is the ‘xenohormesis hypothesis’, the idea that organisms have evolved to respond to stress signalling molecules produced by other species in their environment. In this way, organisms can prepare in advance for a deteriorating environment and/or loss of food supply.
Structure of the Pseudomonas aeruginosa acyl‐homoserinelactone synthase LasI
Authors: Gould Ty A. , Schweizer Herbert P. , Churchill Mair E. A.
Published: August 2004

The LasI/LasR quorum‐sensing system plays a pivotal role in virulence gene regulation of the opportunistic human pathogen, Pseudomonas aeruginosa. Here we report the crystal structure of the acyl‐homoserine lactone (AHL) synthase LasI that produces 3‐oxo‐C12‐AHL from the substrates 3‐oxo‐C12‐acyl‐carrier protein (acyl‐ACP) and S‐adenosyl‐L‐methionine. The LasI six‐stranded beta sheet platform, buttressed by three alpha helices, forms a V‐shaped substrate‐binding cleft that leads to a tunnel passing through the enzyme that can accommodate the acyl‐chain of acyl‐ACP. This tunnel places no apparent restriction on acyl‐chain length, in contrast to a restrictive hydrophobic pocket seen in the AHL‐synthase EsaI. Interactions of essential conserved N‐terminal residues, Arg23, Phe27 and Trp33, suggest that the N‐terminus forms an enclosed substrate‐binding pocket for S‐adenosyl‐L‐methionine. Analysis of AHL‐synthase surface residues identified a binding site for acyl‐ACP, a role that was supported by in vivo reporter assay analysis of the mutated residues, including Arg154 and Lys150. This structure and the novel explanation of AHL‐synthase acyl‐chain‐length selectivity promise to guide the design of Pseudomonas aeruginosa‐specific quorum‐sensing inhibitors as antibacterial agents.
Opioids and the gut: pharmacology and current clinical experience
Authors: De Schepper H. U. , Cremonini F. , Park M.‐I. , Camilleri M.
Published: August 2004

Abstract  This article reviews the pharmacology and physiology of opiate receptors and the current and potential uses of opioid agonists and antagonists in clinical gastroenterology. μ‐receptors are involved in motor and sensory functions, and their modulation is established for treatment of diarrhea. μ‐antagonists have potential to reverse endogenous (e.g., postoperative ileus) or iatrogenic dysmotility (e.g., opioid bowel dysfunction). Modulation of the function of κ‐receptors may be a novel approach to control visceral pain in functional gut disorders. Results of formal testing of novel opioid modulators are keenly awaited.
Cocaine‐ and amphetamine‐regulated transcript stimulates colonic motility via central CRF receptor activation and peripheral cholinergic pathways in fed, conscious rats
Authors: Tebbe J. J. , Ortmann E. , Schumacher K. , Mönnikes H. , Kobelt P. , Arnold R. , Schäfer M. K.‐H.
Published: August 2004

Abstract  Many neuropeptides participating in the hypothalamic control of feeding behaviour and satiety have been shown to be additionally involved in the autonomic control of gastrointestinal (GI) functions. Recently, the neuropeptide cocaine‐ and amphetamine‐regulated transcript (CART) has been indicated to function as an anorectic substance in the brain. In the present study we examine the hypothesis that CART is involved in the modulation of GI motility. Colonic transit time was measured after peripheral and central injection of CART in fed and freely moving Sprague–Dawley rats. Intracerebroventricular injection of synthetic CART (55‐102) (190 pmol and 1.9 nmol per 10 μL and saline controls) decreased the colonic transit time of conscious rats up to 46%. In contrast, i.p. injection of CART (55‐102) (1.9 nmol and 19 nmol kg−1 BW and saline controls) had no effect on colonic motility. Central administration of a CRF receptor antagonist (2.8 nmol) prior to central CART administration antagonized the CART‐induced stimulation of colonic transit. Pretreatment with the peripherally acting cholinergic antagonist atropin methyl nitrate (0.1 mg kg−1 i.p.) blocked the stimulatory CART effect on colonic motor function. The results suggest that CART acts in the central nervous system to modulate behavioural motor function via a central CRF receptor‐dependent mechanism and peripheral cholinergic pathways.
Changes in nitrergic innervation of defunctionalized rat colon after diversion colostomy
Authors: Chaudhury A. , Shariff A. , Srinivas M. , Sabherwal U.
Published: August 2004

Abstract  After 45 days of complete diversion colostomy in male Wistar rats, morphometry of soma and nuclei of NADPH diaphorase positive cells of the myenteric plexus was evaluated. There was a significant (P < 0.0001) diminution in the area, perimeter and volume‐weighted mean volume of soma and nuclei of nitrergic myenteric neurones in the defunctionalized colon. In addition, there was a significant reduction in the neuronal density of the myenteric neurones, and increased distance between the ganglia. In addition, there was myenteric glial atrophy. Atrophy of colonic myenteric neurones was accompanied by significant reduction (P < 0.001) in the volume fraction of the muscularis externa, the prime targets of these neurones. The disturbances in the microecology of the colon may jeopardize the finely orchestrated functioning of the components of the Enteric nervous system (ENS) leading to colonic dysfunction. Our observations, by extrapolation, may explain the bowel dysmotility in humans after restoration of colonic continuity after colostomy.
Scorpion venom stimulates biliary/duodenal motility and pancreatic exocrine secretion
Authors: Chen J. W. C. , Shi C. X. , Teng M. J. , Schloithe A. C. , Toouli J. , Saccone G. T. P.
Published: August 2004

Abstract  Scorpion envenomation causes severe upper abdominal pain associated with nausea and vomiting. Although scorpion venom (SV) stimulates pancreatic and gastric secretion in animal models, its effects on duodenal and biliary motility have not been reported. The aim of this study was to determine the effects of SV on sphincter of Oddi (SO), duodenal and gall bladder motility and pancreatic amylase output. Anaesthetized Australian possums (n = 21) were infused with SV via intravenous or closed intra‐arterial routes. Blood pressure, SO, duodenal and gall bladder motility were continuously monitored for 4 h. Trans‐sphincteric flow (TSF), an indicator of bile duct resistance, was measured concurrently. The amylase output in pancreatic juice was also measured. SV infusion resulted in profound transient increase in blood pressure, SO motility and a significant decrease in TSF. No significant differences were noted in SO basal pressure changes. A transient increase in gall bladder tone, duodenal contraction amplitude and frequency, and amylase output were noted. Following the peak in blood pressure, amylase output, SO, gall bladder and duodenal motility were depressed. SV induces a rapid but transient increase in biliary and duodenal motility that is associated with stimulation of pancreatic amylase output. These changes may contribute to gastrointestinal symptoms associated with early phases of envenomation.
Enforcement of Property Rights and Underdevelopment
Authors: Dabla‐Norris Era , Freeman Scott
Published: August 2004

The authors formalize the role of legal infrastructure in economic development in a general‐equilibrium model with endogenously determined property rights enforcement. The mutual importance of property rights protection and market production is illustrated by the model's multiplicity of equilibria. In one equilibrium, property rights are enforced, and market activity unhampered. In the other, property rights are not enforced, discouraging economic activity, which leaves the economy without the resources and the incentives to enforce property rights. Even identically endowed economies may therefore find themselves in very different equilibria.
Specialization, Transaction Efficiency, and Firm Size: Empirical Evidence
Authors: Lam Kit‐Chun , Liu Pak‐Wai
Published: August 2004

The paper provides some empirical evidence for the relationship between average firm size and the relative transaction efficiency and per capita income as hypothesized by Liu and Yang in Journal of Economic Behavior and Organization 42(2) (2000):145–65. The empirical data of 11 industries in Hong Kong from 1982 to 1999 are found to be broadly consistent with the predictions of Liu and Yang.
SYMPOSIUM: LOCKE AND THE VEIL OF PERCEPTION Preface
Authors: CHAPPELL VERE
Published: August 2004

Abstract:  This Symposium comprises five papers on Locke's theory of sense perception. The authors are John Rogers, Gideon Yaffe, Lex Newman, Tom Lennon, and Martha Bolton. There are also comments on the papers, both individually and as a group, by Vere Chappell. In addition to Locke's view of perception, the papers deal with the nature of Lockean ideas and with the question whether Locke is committed to skepticism regarding the external world. The authors (and the commentator) disagree in their readings of Locke on these issues, but most maintain – and some argue – that he holds a representative theory of perception, and that he is not an external‐world skeptic.
LOCKE AND THE OBJECTS OF PERCEPTION
Authors: ROGERS G. A. J.
Published: August 2004

Abstract:  It is common to assume that if Locke is to be regarded as a consistant epistemologist he must be read as holding that either ideas are the objects of perception or that [physical] objects are. He must either be a direct realist or a representationalist. But perhaps, paradoxical as it at first sounds, there is no reason to suppose that he could not hold both to be true. We see physical objects and when we do so we have ideas. We see or hear birds and bells but we also have visual and auditory ideas of birds and bells. This suggestion is explored through examination of what Locke says about perception in his Elements of Natural Philosophy and the accounts offered both by Locke in the Essay Concerning Human Understanding and by some of Locke's successors.
THROUGH A GLASS DARKLY: MORE ON LOCKE'S LOGIC OF IDEAS
Authors: LENNON THOMAS M.
Published: August 2004

Abstract:  An attempt at defending a version of John Yolton's non‐representationalist reading of Locke's account of perception against Vere Chappell's very threatening criticisms. Concerning this version, which takes ideas to be appearances, Chappell questioned their identity criteria, their relation to what they are appearances of, and their nature in general.
Bodywork Boundaries: Power, Politics and Professionalism in Therapeutic Massage
Authors: Oerton Sarah
Published: August 2004

In the last decade or so, complementary and alternative medicine generally, and therapeutic bodywork in particular, has been attempting to enhance its professional status and standing. By focusing upon the sex/gender dimensions of therapeutic massage and the wider historical, cultural and legal contexts in which such work is situated, this article explores and analyses the discursive formations and practices which women therapeutic massage practitioners deploy in the course of their attempts to achieve professional recognition. Drawing upon both primary and secondary data, it is argued that particular difficulties pertain in the case of the professionalization of therapeutic massage. Because of the widespread elisions between massage and sex work, women therapeutic massage practitioners have to mark out their professional distance from clients by deploying professional identifications and by using boundary‐setting devices or techniques which act to distinguish them from sex workers. This article explores these discursive formations and practices and argues that they act to create near‐intractable problems for women massage practitioners. The article concludes that, because these issues are not commonly acknowledged in much of the academic, policy or practitioner‐orientated literature, the neglect of sex/gender in the case of therapeutic massage has consequences not only for the professionaliza‐tion project of this particular therapeutic modality but for the ways in which various body work occupations in which women predominate tend to be seen as marginal and illegitimate ‘professions’.