bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cryptococcus neoformans Site‐2 protease is required for virulence and survival in the presence of azole drugs
Authors: Bien Clara M. , Chang Yun C. , Nes W. David , Kwon‐Chung Kyung J. , Espenshade Peter J. 
Published: October 2009

SummaryIn the human fungal pathogen Cryptococcus neoformans, the SREBP orthologue Sre1 is important for adaptation and growth in nutrient‐limiting host tissues. In this study, we characterize the C. neoformans serotype A Sre1 and its activating protease, Stp1. We demonstrate that Stp1 is a functionally conserved orthologue of the mammalian Site‐2 protease and that Stp1 cleaves Sre1 within its predicted first transmembrane segment. Gene expression analysis revealed that Stp1 is required for both Sre1‐dependent and Sre1‐independent gene transcription, indicating that other substrates of Stp1 may exist. Using gas chromatography, we showed that Sre1 and Stp1 are required for both normoxic and hypoxic ergosterol biosynthesis, and therefore cells lacking SRE1 or STP1 are defective for growth in the presence of low levels of the ergosterol biosynthesis inhibitors, itraconazole and 25‐thialanosterol. Importantly, our studies demonstrated fungicidal effects of itraconazole and 25‐thialanosterol towards sre1Δ and stp1Δ cells, demonstrating that the Sre1 pathway is required for both growth and survival in the presence of sterol biosynthesis‐inhibiting antifungal drugs. Given the need for fungicidal drugs, we propose that inhibitors of Stp1, Sre1, or other regulators of Sre1 function administered in combination with a sterol synthesis inhibitor could prove an effective anticryptococcal therapy.
A role for tungsten in the biology of Campylobacter jejuni: tungstate stimulates formate dehydrogenase activity and is transported via an ultra‐high affinity ABC system distinct from the molybdate transporter
Authors: Smart Jonathan P. , Cliff Matthew J. , Kelly David J. 
Published: October 2009

SummaryThe food‐borne pathogen Campylobacter jejuni possesses no known tungstoenzymes, yet encodes two ABC transporters (Cj0300–0303 and Cj1538–1540) homologous to bacterial molybdate (ModABC) uptake systems and the tungstate transporter (TupABC) of Eubacterium acidaminophilum respectively. The actual substrates and physiological role of these transporters were investigated. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry of the purified periplasmic binding proteins of each system revealed that while Cj0303 is unable to discriminate between molybdate and tungstate (KD values for both ligands of 4–8 nM), Cj1540 binds tungstate with a KD of 1.0 ± 0.2 pM; 50 000‐fold more tightly than molybdate. Induction‐coupled plasma mass spectroscopy of single and double mutants showed that this large difference in affinity is reflected in a lower cellular tungsten content in a cj1540 (tupA) mutant compared with a cj0303c (modA) mutant. Surprisingly, formate dehydrogenase (FDH) activity was decreased ∼50% in the tupA strain, and supplementation of the growth medium with tungstate significantly increased FDH activity in the wild type, while inhibiting known molybdoenzymes. Our data suggest that C. jejuni possesses a specific, ultra‐high affinity tungstate transporter that supplies tungsten for incorporation into FDH. Furthermore, possession of two MoeA paralogues may explain the formation of both molybdopterin and tungstopterin in this bacterium.
Degradation of nitroaromatic compounds: a model to study evolution of metabolic pathways
Authors: Kivisaar Maia 
Published: October 2009

SummaryAlthough many nitroaromatic compounds have been in nature for only a few decades, bacteria have already evolved the ability to metabolize them. Both horizontal transfer of genes and mutagenesis induced under stressful conditions might facilitate evolution of new catabolic pathways. Nitrotoluene degradation pathways are supposedly derived from an ancestral naphthalene degradation pathway. The 2‐nitrotoluene degradation genes in Acidovorax sp. strain JS42 are controlled by the transcriptional activator NtdR, which differs from NagR, the activator of the naphthalene degradation operon in Ralstonia sp. strain U2, by only five amino acids. Both regulators respond to salicylate, an intermediate of naphthalene degradation, but NtdR also recognizes a wide range of nitroaromatic compounds. In this issue of Molecular Microbiology, Ju et al. present results of site‐directed mutagenesis of NtdR and NagR and show how the nitrotoluene‐responsive regulator NtdR can be generated from a NagR‐like ancestor by only a few mutations. The reconstructed hypothetical pathway for the evolution of NtdR from NagR demonstrates stepwise broadening of the effector range of the evolving protein without loss of the original activity. These results provide strong evidence for the idea that promiscuity of proteins is an important step in the evolution of new functions.
An upstream activation element exerting differential transcriptional activation on an archaeal promoter
Authors: Peng Nan , Xia Qiu , Chen Zhengjun , Liang Yun Xiang , She Qunxin 
Published: October 2009

SummaryMicroorganisms can utilize different sugars as energy and carbon sources and the genes involved in sugar metabolism often exhibit highly regulated expression. To study cis‐acting elements controlling arabinose‐responsive expression in archaea, the promoter of the Sulfolobus solfataricus araS gene encoding an arabinose binding protein was characterized using an Sulfolobus islandicus reporter gene system. The minimal active araS promoter (ParaS) was found to be 59 nucleotides long and harboured four promoter elements: an ara‐box, an upstream transcription factor B‐responsive element (BRE), a TATA‐box and a proximal promoter element, each of which contained important nucleotides that either greatly decreased or completely abolished promoter activity upon mutagenesis. The basal araS promoter was virtually inactive due to intrinsically weak BRE element, and the upstream activating sequence (UAS) ara‐box activated the basal promoter by recruiting transcription factor B to its BRE. While this UAS ensured a general expression from an inactive or weak basal promoter in the presence of other tested carbon resources, it exhibited a strong arabinose‐responsive transcriptional activation. To our knowledge, this represents the first example of an archaeal UAS that exhibits differential activation to the expression on the same promoter in the presence of different carbon sources.
Replication fork collisions cause pathological chromosomal amplification in cells lacking RecG DNA translocase
Authors: Rudolph Christian J. , Upton Amy L. , Lloyd Robert G. 
Published: October 2009

SummaryDuplication and transmission of chromosomes require precise control of chromosome replication and segregation. Here we present evidence that RecG is a major factor influencing these processes in bacteria. We show that the extensive DnaA‐independent stable DNA replication observed without RecG can lead to replication of any area of the chromosome. This replication is further elevated following irradiation with UV light and appears to be perpetuated by secondary events that continue long after the elimination of UV lesions. The resulting pathological cascade is associated with an increased number of replication forks traversing the chromosome, sometimes with extensive regional amplification of the chromosome, and with the accumulation of highly branched DNA intermediates containing few Holliday junctions. We propose that the cascade is triggered by replication fork collisions that generate 3′ single‐strand DNA flaps, providing sites for PriA to initiate re‐replication of the DNA and thus to generate linear duplexes that provoke recombination, allowing priming of even further replication. Our results shed light on why termination of replication in bacteria is normally limited to a single encounter of two forks and carefully orchestrated within a restricted area, and explain how a system of multiple forks and random termination can operate in eukaryotes.
Listeria monocytogenes CtaP is a multifunctional cysteine transport‐associated protein required for bacterial pathogenesis
Authors: Xayarath Bobbi , Marquis Hélène , Port Gary C. , Freitag Nancy E. 
Published: October 2009

SummaryThe bacterial pathogen Listeria monocytogenes survives under a myriad of conditions in the outside environment and within the human host where infections can result in severe disease. Bacterial life within the host requires the expression of genes with roles in nutrient acquisition as well as the biosynthesis of bacterial products required to support intracellular growth. A gene product identified as the substrate‐binding component of a novel oligopeptide transport system (encoded by lmo0135) was recently shown to be required for L. monocytogenes virulence. Here we demonstrate that lmo0135 encodes a multifunctional protein that is associated with cysteine transport, acid resistance, bacterial membrane integrity and adherence to host cells. The lmo0135 gene product (designated CtaP, for cysteine transport associated protein) was required for bacterial growth in the presence of low concentrations of cysteine in vitro, but was not required for bacterial replication within the host cytosol. Loss of CtaP increased membrane permeability and acid sensitivity, and reduced bacterial adherence to host cells. ctaP deletion mutants were severely attenuated following intragastric and intravenous inoculation of mice. Taken together, the data presented indicate that CtaP contributes to multiple facets of L. monocytogenes physiology, growth and survival both inside and outside of animal cells.
Cell elongation and branching are regulated by differential phosphorylation states of the nuclear Dbf2‐related kinase COT1 in Neurospora crassa
Authors: Ziv Carmit , Kra‐Oz Galia , Gorovits Rena , März Sabine , Seiler Stephan , Yarden Oded 
Published: October 2009

SummaryDysfunction of the Neurospora crassa nuclear Dbf2‐related kinase COT1 leads to cessation of tip extension and massive induction of new sites of growth. To determine the role phosphorylation plays in COT1 function, we mutated COT1 residues corresponding to positions of highly conserved nuclear Dbf2‐related phosphorylation sites. Analyses of the point‐mutation cot‐1 strains (mimicking non‐ and constitutively phosphorylated states) indicate the involvement of COT1 phosphorylation in the regulation of hyphal elongation and branching as well as asexual development by altering cell wall integrity and actin organization. Phosphorylation of COT1's activation segment (at Ser417) is required for proper in vitro kinase activity, but has only a limited effect on hyphal growth. In marked contrast, even though phosphorylation of the C‐terminal hydrophobic motif (at Thr589) is crucial for all COT1 functions in vivo, the lack of Thr589 phosphorylation did not significantly affect in vitro COT1 kinase activity. Nevertheless, its regulatory role has been made evident by the significant increase observed in COT1 kinase activity when this residue was substituted in a manner mimicking constitutive phosphorylation. We conclude that COT1 regulates elongation and branching in an independent manner, which is determined by its phosphorylation state.
Parasites as aetiological agents in chronic diseases. Epidemiological associations and potential mechanisms of pathogenesis
Authors: BROWN M. 
Published: October 2009

SummaryThe aetiological role of parasitic infection has been well established, through epidemiological studies, for many chronic diseases prevalent in the tropics. Examples include Schistosoma mansoni infection leading to portal hypertension, Schistosoma haematobium infection leading to obstructive uropathy and squamous cell carcinoma of the bladder, Clonorchis sinensis leading to cholangiocarcinoma, and Taenia solium infection leading to epilepsy. Our understanding of the pathogenesis of these associations, however, continues to evolve, with new insights from many fertile avenues in chronic disease research. There are also tenuous associations such as schizophrenia with toxoplasmosis, and the findings from observational studies that link malignancy and epilepsy with a range of helminthic infections. Imprecise case definitions, and the lack of good animal models, are limitations to the evidence for a causal role of parasitic infection in these diseases.
Assessment of need and capacity to benefit for people with a disability requiring aids, appliances and equipment
Authors: Masso Malcolm , Owen Alan , Stevermuer Tara , Williams Kathryn , Eagar Kathy 
Published: October 2009

Aim:  To develop an equitable system for allocating equipment, aids and appliances to adults with disabilities based on assessment of need and capacity to benefit for use by occupational therapists, who are the main professional group involved in assessing and prioritising applications. Methods:  An assessment tool was developed, pilot tested and field tested at four sites in New South Wales. Assessments were undertaken in parallel with existing systems. Feedback on use of the tool was obtained from those conducting the assessments and those making decisions to fund applications for equipment based on the assessments. Results:  One hundred and six assessments were undertaken. Applications for bed, sleeping and seating equipment and equipment to assist with mobility, toileting, showering and transfers accounted for 94.2% of equipment requested. Provision of equipment was expected to have greatest impact on the physical effort and safety of carers and the safety and quality of life of applicants. Regression analysis identified assessment items that explain variation between applicants and that can avoid unnecessary data collection. Conclusions:  The assessment tool provides a standardised method for assessing requests for equipment based on the twin concepts of need and capacity to benefit. The results support the use of both concepts as the foundation of the assessment process. Further development is required, particularly to move to the next stage of using the assessment tool as the basis for prioritising applications for equipment.
A model for play‐based intervention for children with ADHD
Authors: Cordier Reinie , Bundy Anita , Hocking Clare , Einfeld Stewart 
Published: October 2009

Background/aim: The importance of play in the social development of children is undisputed. Even though children with attention‐deficit hyperactivity disorder (ADHD) experience serious social problems, there is limited research on their play. By integrating literature on ADHD with literature on play, we can postulate how play is influenced by the characteristics of ADHD. These postulations enabled us to propose a theoretical model (proposed model) to depict the interactive process between the characteristics of ADHD and factors that promote play. This paper presents the revised model and principles for intervention based on the results of a study investigating the play of children with ADHD (reported elsewhere).Methods: We tested the proposed model in a study comparing two groups of children (n = 350) between the ages of 5 and 11 years. One group consisted of children diagnosed with ADHD (n = 112) paired with playmates (n = 112) who were typically developing; the control group consisted of typically developing children paired with typically developing playmates (n = 126). The Test of Playfulness was administered, and the model was revised in line with the findings.Results and conclusions: The findings suggest difficulties in the social play and lack of interpersonal empathy in the play of children with ADHD. We draw on the revised model to propose preliminary principles for play‐based interventions for children with ADHD. The principles emphasise the importance of capturing the motivation of children with ADHD, counteracting the effects of lack of interpersonal empathy, and considerations for including playmates in the intervention process.
A novel device (SD‐101) with high accuracy for screening sleep apnoea‐hypopnoea syndrome
Authors: AGATSUMA Toshihiko , FUJIMOTO Keisaku , KOMATSU Yoshimichi , URUSHIHATA Kazuhisa , HONDA Takayuki , TSUKAHARA Teruomi , NOMIYAMA Tetsuo 
Published: October 2009

ABSTRACTBackground and objective:  The SD‐101 is a non‐restrictive, sheet‐like medical device with an array of pressure sensors, to detect sleep‐disordered breathing by sensing gravitational alterations in the body corresponding to respiratory movements. This study evaluated the accuracy of the SD‐101 for screening sleep apnoea‐hypopnoea syndrome (SAHS) by comparison with polysomnography.Methods:  Nocturnal polysomnography and SD‐101 monitoring were conducted simultaneously and compared in 201 patients with suspected SAHS (suspected SAHS group) and 165 male employees of a transport company (screening group).Results:  Polysomnography revealed an AHI of <5, 5 ≤ AHI < 15, 15 ≤ AHI < 30, 30 ≤ AHI < 60 and AHI ≥ 60 events/h in 39, 35, 38, 68 and 21 subjects in the suspected SAHS group and 103, 34, 12, 12 and four subjects in the screening group, respectively. Central SAHS and obstructive SAHS were subsequently diagnosed in 11 (5.5%) and 135 (67.2%) of subjects in the suspected SAHS group and five (3.0%) and 39 (23.6%) of subjects in the screening group, respectively. Significant correlations were apparent between AHI and the respiratory disturbance index (RDI) measured with the SD‐101 in both the suspected SAHS group (r = 0.88) and screening group (r = 0.92). Receiver operating characteristic curve analysis revealed 89.5% sensitivity and 85.8% specificity in identifying SAHS, using an RDI of 14.0 events/h.Conclusions:  These findings suggest that the SD‐101 is a useful device for screening SAHS.
Monoclonal anti‐vascular endothelial growth factor antibody reduces fluid volume in an experimental model of inflammatory pleural effusion
Authors: RIBEIRO Sabrina C.C. , VARGAS Francisco S. , ANTONANGELO Leila , MARCHI Evaldo , GENOFRE Eduardo H. , ACENCIO Milena M.P. , TEIXEIRA Lisete R. 
Published: October 2009

ABSTRACTBackground and objective:  Vascular endothelial growth factor (VEGF) is known to increase vascular permeability and promote angiogenesis. It is expressed in most types of pleural effusions. However, the exact role of VEGF in the development of pleural effusions has yet to be determined. The anti‐VEGF mAb, bevacizumab, has been used in the treatment of cancer to reduce local angiogenesis and tumour progression. This study describes the acute effects of VEGF blockade on the expression of inflammatory cytokines and pleural fluid accumulation.Methods:  One hundred and twelve New Zealand rabbits received intrapleural injections of either talc or silver nitrate. In each group, half the animals received an intravenous injection of bevacizumab, 30 min before the intrapleural agent was administered. Five animals from each subgroup were sacrificed 1, 2, 3, 4 or 7 days after the procedure. Twelve rabbits were used to evaluate vascular permeability using Evans's blue dye. Pleural fluid volume and cytokines were quantified.Results:  Animals pretreated with anti‐VEGF antibody showed significant reductions in pleural fluid volumes after talc or silver nitrate injection. IL‐8 levels, vascular permeability and macroscopic pleural adhesion scores were also reduced in the groups that received bevacizumab.Conclusions:  This study showed that bevacizumab interferes in the acute phase of pleural inflammation induced by silver nitrate or talc, reinforcing the role of VEGF as a key mediator in the production of pleural effusions. The results also suggest that bevacizumab should probably be avoided in patients requiring pleurodesis.
How to diagnose multiple sclerosis and what are the pitfalls
Authors: Shaw C. , Chapman C. , Butzkueven H. 
Published: October 2009

AbstractThe task of confirming a diagnosis of multiple sclerosis (MS), one of the commonest neurological disorders affecting young adults, has altered significantly in the magnetic resonance imaging era. Conversely, key principles, most notably objective documentation of neurological dissemination in time and space, remain fundamental to the process. Clinical acumen and experience are equally as crucial as an ability to interpret relevant investigations. Recognising typical clinical patterns, addressing potential ‘mimics’, and stratifying prognosis of a clinically isolated syndrome are just some of the challenges inherent in diagnosing MS.
Enhanced regenerative axon growth of multiple fibre populations in traumatic spinal cord injury following scar‐suppressing treatment
Authors: Schiwy Nora , Brazda Nicole , Müller Hans Werner 
Published: October 2009

AbstractWe analysed the effect of scar‐suppressing treatment (anti‐scarring treatment; AST) on augmenting axonal regeneration of various neuronal populations following spinal cord injury (SCI) in adult rat. AST included local iron chelator (2,2′‐dipyridine‐5,5′‐dicarboxylic acid) injection and 8‐bromo‐cyclic adenosine monophosphate application to the lesion core. In previous studies, this treatment promoted long‐distance regeneration of cut corticospinal tract axons, neuroprotection of projecting cortical neurons and functional improvement of treated rats [N. Klapka et al. (2005)Eur. J. Neurosci., 22, 3047–3058]. Treatment yielded significantly enhanced regrowth of descending serotonergic (5‐HT), catecholaminergic (tyrosine hydroxylase; TH), corticospinal and rubrospinal axons into the lesion zone, as assessed by anterograde tracing and immunohistochemistry followed by quantification of axon profiles at 5 and 12 weeks post‐injury. In addition, the determination of axons crossing the proximal borderline from uninjured tissue into fibrous scar area revealed a significant AST‐promoted increase of intersecting fibres for 5‐HT, TH and calcitonin gene‐related peptide containing ascending sensory fibres. For a prolonged time period after lesion, the delayed (secondary) scar developing in treated rats is significantly more permeable for all analysed axon tracts than the initial (primary) scar forming in injured control animals lacking treatment. Furthermore, enhanced outgrowth of descending axons from fibrous scar into distal healthy spinal tissue was achieved in treated animals, and is in line with previous functional studies [S. Hermanns et al. (2001) Restor. Neurol. Neurosci., 19,139–148; N. Klapka et al. (2005)Eur. J. Neurosci., 22, 3047–3058]. Our findings indicate that AST exerts a prolonged beneficial effect on fibrous scarring allowing enhanced axonal regrowth of different fibre tracts in SCI regardless of their distinct regenerative demands.
Pairing mild stress with increased serotonin‐1B receptor expression in the nucleus accumbens increases susceptibility to amphetamine
Authors: Ferguson Susan M. , Sandygren Nolan A. , Neumaier John F. 
Published: October 2009

AbstractBoth serotonin‐1B (5‐HT1B) receptors and stress modulate the behavioral and neurobiological effects of psychostimulant drugs. In order to examine how these factors interact to influence the development of behaviors associated with addiction, we used viral‐mediated gene transfer to transiently increase expression of 5‐HT1Breceptors in the nucleus accumbens (NAc) shell along with exposure to repeated mild stress (novelty + saline injection) in rats. Once the viral‐mediated increases in gene expression had dissipated, the resulting effects of this 5‐HT1B/stress pairing on the acute locomotor response to amphetamine and on the development of psychomotor sensitization were examined. We report that the increasing expression of 5‐HT1Breceptors on the terminals of NAc shell neurons that project to the ventral tegmental area and repeatedly exposing rats to mild stress subsequently enhance the acute locomotor‐activating effects of amphetamine. In addition, the development of psychomotor sensitization (both locomotor activity and stereotypy components) is facilitated. These results suggest that serotonin signaling through NAc 5‐HT1Bheteroreceptors can interact with stress to increase susceptibility to the enduring forms of drug‐induced plasticity that are associated with addiction.