bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid reuteransucrase enzymes reveal regions important for glucosidic linkage specificity and the transglucosylation/hydrolysis ratio
Authors: Kralj Slavko , van Leeuwen Sander S. , Valk Vincent , Eeuwema Wieger , Kamerling Johannis P. , Dijkhuizen Lubbert
Published: November 2008

The reuteransucrase enzymes of Lactobacillus reuteri strain 121 (GTFA) and L. reuteri strain ATCC 55730 (GTFO) convert sucrose into α‐d‐glucans (labelled reuterans) with mainly α‐(1→4) glucosidic linkages (50% and 70%, respectively), plus α‐(1→6) linkages. In the present study, we report a detailed analysis of various hybrid GTFA/O enzymes, resulting in the identification of specific regions in the N‐termini of the catalytic domains of these proteins as the main determinants of glucosidic linkage specificity. These regions were divided into three equal parts (A1–3; O1–3), and used to construct six additional GTFA/O hybrids. All hybrid enzymes were able to synthesize α‐glucans from sucrose, and oligosaccharides from sucrose plus maltose or isomaltose as acceptor substrates. Interestingly, not only the A2/O2 regions, with the three catalytic residues, affect glucosidic linkage specificity, but also the upstream A1/O1 regions make a strong contribution. Some GTFO derived hybrid/mutant enzymes displayed strongly increased transglucosylation/hydrolysis activity ratios. The reduced sucrose hydrolysis allowed the much improved conversion of sucrose into oligo‐ and polysaccharide products. Thus, the glucosidic linkage specificity and transglucosylation/hydrolysis ratios of reuteransucrase enzymes can be manipulated in a relatively simple manner. This engineering approach has yielded clear changes in oligosaccharide product profiles, as well as a range of novel reuteran products differing in α‐(1→4) and α‐(1→6) linkage ratios.
Cell‐penetrating peptide‐conjugated XIAP‐inhibitory cyclic hexapeptides enter into Jurkat cells and inhibit cell proliferation
Authors: Sasaki Yusuke , Minamizawa Motoko , Ambo Akihiro , Sugawara Shigeki , Ogawa Yukiko , Nitta Kazuo
Published: November 2008

X‐Linked inhibitor of apoptosis protein (XIAP) is a member of the inhibitor of apoptosis protein family that is overexpressed in human cancers. There is great interest in the development of XIAP inhibitors, which are predicted to promote apoptosis in cancer cells and thus have therapeutic potential. A cyclic hexapeptide (CH), CPFKQC, which is one of the consensus motifs that can bind to the baculovirus IAP repeat 2 domain of XIAP, has been identified using phage‐displayed combinatorial chemistry techniques [Tamm I, Trepel M, Cardo‐Vila M, Sun Y, Welsh K, Cabezas E, Swatterthwait A, Arap W, Reed JC & Pasqualini R (2003) Peptides targeting caspase inhibitors. J Biol Chem278, 14401–14405]. In this study, we designed and synthesized covalently linked conjugates of CHs, cyclo[Cys‐Pro‐Xaa‐Lys‐Gln‐Glu(‐CO‐)‐NH2] (Xaa = various amino acids; cyclization via a peptide bond between the N‐terminal amino group of Cys1 and the side‐chain carboxylic acid of Glu6), and a cell‐penetrating peptide (CPP), Ac‐Cys‐Trp‐(Arg)8‐Lys‐NH2. CH–CPP conjugates (CHCPPs) with aromatic and hydrophobic Xaa residues, such as Phe (CHCPP 1), 2,6‐dimethyl‐phenylalanine (CHCPP 2) and 3‐(1‐naphthyl)‐alanine/3‐(2‐naphthyl)‐alanine (CHCPPs 3 and 4), potently inhibited the proliferation of Jurkat cells in a dose‐dependent manner, whereas analogues with nonaromatic or less hydrophobic amino acids at the Xaa residue were less potent or caused no inhibition. A morphological study of nuclei after treatment with CHCPPs 1–4 revealed that nuclear fragmentation occurred, suggesting that these conjugates induce apoptosis. A kinetic study of the uptake of fluorescein‐labelled CHCPP 2 into the cells showed that the conjugates were translocated within a few minutes. The cellular uptake of fluorescein isothiocyanate‐labelled CHCPP 1 and CPP was greatly reduced in high‐K+ buffers, suggesting that CPP and its conjugate are translocated by a mechanism associated with cell membrane potential. Competitive binding studies performed using fluorescence correlation spectroscopy demonstrated that CHCPP 1 binds to the baculovirus IAP repeat 2 domain of XIAP via the CH (Xaa = Phe) moiety. CHCPPs 1 and 2 showed the most potent inhibitory activity of the CHCPPs and embelin, a nonpeptide inhibitor of XIAP, suggesting that they are good templates for the design of a new class of anticancer drug.
Invasion of enteropathogenic Escherichia coli into host cells through epithelial tight junctions
Authors: Li Qiurong , Zhang Qiang , Wang Chenyang , Li Ning , Li Jieshou
Published: November 2008

Enteropathogenic Escherichia coli (EPEC) has been shown to disrupt the barrier function of host intestinal epithelial tissues through entering tight junctions. However, the mechanism by which this occurs remains poorly understood. In this study, we determined that EPEC invades host cells through tight junctions as it initiates infection. Immunofluorescence microscopy revealed redistribution of the tight‐junction proteins occludin and ZO‐1 from an intercellular to a cytoplasmic location after EPEC invasion. Flotillin‐1 was recruited to sites of EPEC entry. EPEC entered host cells through tight‐junction membrane microdomains. Tight‐junction ultrastructure was disrupted following EPEC infection, accompanied by loss of barrier function. EPEC infection caused a time‐dependent decrease in trans‐epithelial electrical resistance. Subcellular fractionation using discontinuous sucrose density gradients demonstrated a decline in raft‐associated occludin following exposure to EPEC. These results indicate the important role of host membrane tight‐junction microdomains in EPEC invasion.
Clitoral Atrophy: A Case Series
Authors: Amsterdam Alison , Krychman Michael
Published: November 2008

Introduction

Clitoral atrophy is often a neglected cause of female arousal complaints and warrants treatment with localized treatments.

Aim

This is a case series of patients with clitoral atrophy in which localized estrogens were used to treat separate, distinct sexual complaints.

Methods

We report on three patients who were treated with localized estrogen tablets and cream for symptomatic clitoral atrophy despite a lack of data for use of these agents for the treatment of this diagnosis. The patients described here expressed understanding of the risks of vaginal hormonal therapy prior to treatment and at follow-up visits while on therapy.

Main Outcome Measures

Patient reports, physical examination, and vaginal pH.

Results

All patients reported improvement or resolution of symptoms after the treatment with localized estrogen tablets and/or cream.

Conclusions

Low-dose minimally absorbed local estrogen products can be used in combination with excellent tolerance and low side-effect profile to treat female sexual complaints.
La réforme des pensions en Chine
Authors: Salditt Felix , Whiteford Peter , Adema Willem
Published: November 2008

Résumé  L'article analyse les progrès accomplis par la Chine dans la création d'un système d'assurance vieillesse et fournit une description détaillée du système et une évaluation de la mesure dans laquelle ce système a déjà atteint son but premier: la sécurité sociale pour un plus grand nombre de personnes. Depuis 1997, les réformes ont été nombreuses mais, malgré les progrès accomplis, la portée du système est limitée: le taux de couverture des travailleurs des zones urbaines est inférieur à 50 pour cent. La population des zones rurales reste largement exclue du système, et il semble probable que la majorité de la population dépendra pendant de nombreuses années encore du soutien familial. Il existe une «fenêtre démographique» d'opportunité pour s'attaquer à ces lacunes, qui se refermera aux environs de 2015. L'extension de la protection par un meilleur respect des règles par les travailleurs et les entreprises ainsi que l'engagement financier soutenu vis‐à‐vis du Fonds national de la sécurité sociale sont essentiels si l'on veut créer le fondement financier et institutionnel qui peut amortir les effets d'une population beaucoup plus âgée dans les années à venir.
La probabilité d’un revenu de base en Allemagne
Authors: Opielka Michael
Published: November 2008

Résumé  L’article examine si la probabilité de voir l’Allemagne adopter, dans le cadre de sa politique sociale, un revenu de base indépendant de la participation au marché du travail a augmenté ces dernières années. Après une description succincte des principes de base de l’Etat providence allemand, l’article présente une analyse critique de l’évolution récente de la garantie d’un revenu de base par la fusion, depuis 2003, des prestations de chômage et de l’aide sociale. Depuis lors, les craintes que cette fusion a suscitées jusque dans les classes moyennes ont ranimé le débat des années quatre‐vingt sur le revenu de base. A la lumière de l’exemple de deux modèles (la «garantie du revenu de base» et le «revenu citoyen de solidarité»), il examine les problèmes concrets de conception du système et la probabilité de sa mise en œuvre effective.
China's Grand Strategy, the Korean Nuclear Crisis, and the Six‐Party Talks
Authors: Horowitz Shale , Ye Min
Published: November 2008

North Korea has pursued a nuclear weapons capability for about two decades. Many diplomatic efforts have been made to convince or cajole the Northern regime to give up this quest – and all have so far failed. Since 2003, a new multilateral approach – the Six‐Party Talks involving the Koreas, China, Japan, Russia, and the United States – has raised hopes anew. These hopes are based largely on China playing an active role. China has the potential both to guarantee North Korea's security, and to impose and enforce a denuclearization agreement. We analyze China's changing grand strategy and its implications for China's Korea goals and policies. To Deng Xiaoping's emphasis on China's national interests, China's third‐ and fourth‐generation leaders have added a greater reliance on foreign and military policies to maintain domestic political support and legitimacy. This discussion indicates that China is currently more concerned to preserve the North Korean regime and prevent a second Korean War than to eliminate the North's nuclear capability. Therefore, the Six‐Party Talks are unlikely to succeed.
Dynamic Modeling and Analysis of Tooth Profile Modification for Multimesh Gear Vibration
Authors: Liu Gang , Parker Robert G.
Published: November 2008

This work studies the effects of tooth profile modification on multimesh gearset vibration. The nonlinear analytical model considers the dynamic load distribution between the individual gear teeth and the influence of variable mesh stiffnesses, profile modifications, and contact loss. The proposed model yields better agreement than two existing models when compared against nonlinear gear dynamics from a finite element/contact mechanics benchmark. These comparisons are made for different loads, profile modifications, and bearing stiffness conditions. This model captures the total and partial contact losses demonstrated by finite element. Perturbation analysis based on the proposed model finds approximate frequency response solutions for the case of no total contact loss due to the optimized system parameters. The closed-form solution is compared with numerical integration and provides guidance for optimizing mesh phasing, contact ratios, and profile modification magnitude and length.
Compliant Wireform Mechanisms
Authors: Pendleton Tyler M. , Jensen Brian D.
Published: November 2008

This paper presents an alternative to fabrication methods commonly used in compliant mechanisms research, resulting in a new class of compliant mechanisms called wireform mechanisms. This technique integrates torsional springs made of formed wire into compliant mechanisms. In this way the desired force, stiffness, and motion can be achieved from a single piece of formed wire. Two techniques of integrating torsion springs are fabricated and modeled: helical coil torsion springs and torsion bars. Because the mechanisms are more complex than ordinary springs, simplified models, which aid in design, are presented, which represent the wireform mechanisms as rigid-body mechanisms using the pseudo-rigid-body model. The method is demonstrated through the design of a mechanically tristable mechanism. The validity of the simplified models is discussed by comparison to finite element models and, in the case of the torsion-bar mechanism, to experimental measurements.
Design and Prototyping of a Partially Decoupled 4-DOF 3T1R Parallel Manipulator With High-Load Carrying Capacity
Authors: Briot Sébastien , Arakelian Vigen , Guégan Sylvain
Published: November 2008

In this paper, a new four degrees of freedom 3T1R parallel manipulator with high-load carrying capacity is presented. This manipulator generates Schönflies motions, in which the moving platform carries out three independent translations and one rotation about one axis of fixed orientation. The particularity of the proposed architecture is the decoupling of the displacements of the platform in the horizontal plane from the platform’s translation along the vertical axis. Such a decoupling allows the cancellation of the gravity loads on the actuators, which displace the platform in the horizontal plane. A prototype of the proposed manipulator with four degrees of freedom and an experimental validation of the suggested concept are also presented. Two cases have been examined on the built prototype: a manipulator with payload and one without. It was shown that the input torques of actuators displacing the platform in the horizontal plane for these two cases are the same; i.e., the payload does not bring any load to the actuators.
Exploring the Use of Functional Models in Biomimetic Conceptual Design
Authors: Nagel Robert L. , Midha Prem A. , Tinsley Andrea , Stone Robert B. , McAdams Daniel A. , Shu L. H.
Published: November 2008

The biological world provides numerous cases for analogy and inspiration. From simple cases such as hook and latch attachments to articulated-wing flying vehicles, nature provides many sources for ideas. Though biological systems provide a wealth of elegant and ingenious approaches to problem solving, there are challenges that prevent designers from leveraging the full insight of the biological world into the designed world. This paper describes how those challenges can be overcome through functional analogy. Through the creation of a function-based repository, designers can find biomimetic solutions by searching the function for which a solution is needed. A biomimetic function-based repository enables learning, practicing, and researching designers to fully leverage the elegance and insight of the biological world. In this paper, we present the initial efforts of functional modeling biological systems and then transferring the principles of the biological system to an engineered system. Four case studies are presented in this paper. These case studies include a biological solution to a problem found in nature and engineered solutions corresponding to the high-level functionality of the biological solution, i.e., a housefly’s winged flight and a flapping wing aircraft. The case studies show that unique creative engineered solutions can be generated through functional analogy with nature.
Genetic Mapping in Human Disease
Authors: Altshuler David , Daly Mark J. , Lander Eric S.
Published: November 2008

Genetic mapping provides a powerful approach to identify genes and biological processes underlying any trait influenced by inheritance, including human diseases. We discuss the intellectual foundations of genetic mapping of Mendelian and complex traits in humans, examine lessons emerging from linkage analysis of Mendelian diseases and genome-wide association studies of common diseases, and discuss questions and challenges that lie ahead.
Response to Comment on "Whole-Genome Shotgun Sequencing of Mitochondria from Ancient Hair Shafts"
Authors: Gilbert M. Thomas P. , Miller Webb , Schuster Stephan C.
Published: November 2008

Debruyneet al. challenge the findings of our study and imply that we argue that hair shafts are an overall superior source of ancient DNA than bone. However, the authors are misreading and misinterpreting the conclusions of our study; we claim nothing further than that hair shaft represents an excellent source material for the shotgun sequencing of mitochondrial DNA genomes.
Oxytocin, Vasopressin, and the Neurogenetics of Sociality
Authors: Donaldson Zoe R. , Young Larry J.
Published: November 2008

There is growing evidence that the neuropeptides oxytocin and vasopressin modulate complex social behavior and social cognition. These ancient neuropeptides display a marked conservation in gene structure and expression, yet diversity in the genetic regulation of their receptors seems to underlie natural variation in social behavior, both between and within species. Human studies are beginning to explore the roles of these neuropeptides in social cognition and behavior and suggest that variation in the genes encoding their receptors may contribute to variation in human social behavior by altering brain function. Understanding the neurobiology and neurogenetics of social cognition and behavior has important implications, both clinically and for society.
Wired for Sex: The Neurobiology of
Drosophila
Mating Decisions
Authors: Dickson Barry J.
Published: November 2008

Decisions about whom to mate with can sometimes be difficult, but making the right choice is critical for an animal's reproductive success. The ubiquitous fruit fly,
Drosophila
, is clearly very good at making these decisions. Upon encountering another fly, a male may or may not choose to court. He estimates his chances of success primarily on the basis of pheromone signals and previous courtship experience. The female decides whether to accept or reject the male, depending on her perception of his pheromone and acoustic signals, as well as her own readiness to mate. This simple and genetically tractable system provides an excellent model to explore the neurobiology of decision making.
Genes and Social Behavior
Authors: Robinson Gene E. , Fernald Russell D. , Clayton David F.
Published: November 2008

What genes and regulatory sequences contribute to the organization and functioning of neural circuits and molecular pathways in the brain that support social behavior? How does social experience interact with information in the genome to modulate brain activity? Here, we address these questions by highlighting progress that has been made in identifying and understanding two key “vectors of influence” that link genes, the brain, and social behavior: (i) Social information alters gene expression in the brain to influence behavior, and (ii) genetic variation influences brain function and social behavior. We also discuss how evolutionary changes in genomic elements influence social behavior and outline prospects for a systems biology of social behavior.
PirB is a Functional Receptor for Myelin Inhibitors of Axonal Regeneration
Authors: Atwal Jasvinder K. , Pinkston-Gosse Julie , Syken Josh , Stawicki Scott , Wu Yan , Shatz Carla , Tessier-Lavigne Marc
Published: November 2008

A major barrier to regenerating axons after injury in the mammalian central nervous system is an unfavorable milieu. Three proteins found in myelin—Nogo, MAG, and OMgp—inhibit axon regeneration in vitro and bind to the glycosylphosphatidylinositol-anchored Nogo receptor (NgR). However, genetic deletion of NgR has only a modest disinhibitory effect, suggesting that other binding receptors for these molecules probably exist. With the use of expression cloning, we have found that paired immunoglobulin-like receptor B (PirB), which has been implicated in nervous system plasticity, is a high-affinity receptor for Nogo, MAG, and OMgp. Interfering with PirB activity, either with antibodies or genetically, partially rescues neurite inhibition by Nogo66, MAG, OMgp, and myelin in cultured neurons. Blocking both PirB and NgR activities leads to near-complete release from myelin inhibition. Our results implicate PirB in mediating regeneration block, identify PirB as a potential target for axon regeneration therapies, and provide an explanation for the similar enhancements of visual system plasticity in PirB and NgR knockout mice.
Promoting Axon Regeneration in the Adult CNS by Modulation of the PTEN/mTOR Pathway
Authors: Park Kevin Kyungsuk , Liu Kai , Hu Yang , Smith Patrice D. , Wang Chen , Cai Bin , Xu Bengang , Connolly Lauren , Kramvis Ioannis , Sahin Mustafa , He Zhigang
Published: November 2008

The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathway, in adult retinal ganglion cells (RGCs) promotes robust axon regeneration after optic nerve injury. In wild-type adult mice, the mTOR activity was suppressed and new protein synthesis was impaired in axotomized RGCs, which may contribute to the regeneration failure. Reactivating this pathway by conditional knockout of tuberous sclerosis complex 1, another negative regulator of the mTOR pathway, also leads to axon regeneration. Thus, our results suggest the manipulation of intrinsic growth control pathways as a therapeutic approach to promote axon regeneration after CNS injury.
Fat Metabolism Links Germline Stem Cells and Longevity in
C. elegans
Authors: Wang Meng C. , O'Rourke Eyleen J. , Ruvkun Gary
Published: November 2008

Fat metabolism, reproduction, and aging are intertwined regulatory axes; however, the mechanism by which they are coupled remains poorly understood. We found that germline stem cells (GSCs) actively modulate lipid hydrolysis in
Caenorhabditis elegans
, which in turn regulates longevity. GSC arrest promotes systemic lipolysis via induction of a specific fat lipase. Subsequently, fat mobilization is promoted and life span is prolonged. Constitutive expression of this lipase in fat storage tissue generates lean and long-lived animals. This lipase is a key factor in the lipid hydrolysis and increased longevity that are induced by decreased insulin signaling. These results suggest a link between
C. elegans
fat metabolism and longevity.
A Test of Climate, Sun, and Culture Relationships from an 1810-Year Chinese Cave Record
Authors: Zhang Pingzhong , Cheng Hai , Edwards R. Lawrence , Chen Fahu , Wang Yongjin , Yang Xunlin , Liu Jian , Tan Ming , Wang Xianfeng , Liu Jinghua , An Chunlei , Dai Zhibo , Zhou Jing , Zhang Dezhong , Jia Jihong , Jin Liya , Johnson Kathleen R.
Published: November 2008

A record from Wanxiang Cave, China, characterizes Asian Monsoon (AM) history over the past 1810 years. The summer monsoon correlates with solar variability, Northern Hemisphere and Chinese temperature, Alpine glacial retreat, and Chinese cultural changes. It was generally strong during Europe's Medieval Warm Period and weak during Europe's Little Ice Age, as well as during the final decades of the Tang, Yuan, and Ming Dynasties, all times that were characterized by popular unrest. It was strong during the first several decades of the Northern Song Dynasty, a period of increased rice cultivation and dramatic population increase. The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.
Effects of Extracellular ATP on Bovine Lung Endothelial and Epithelial Cell Monolayer Morphologies, Apoptoses, and Permeabilities
Authors: McClenahan David , Hillenbrand Kati , Kapur Arvinder , Carlton David , Czuprynski Charles
Published: November 2008

Pneumonia in cattle is an important disease both economically and in terms of animal welfare. Recent evidence in other species has shown ATP to be an important modulator of inflammation in the lung, where it is released by activated alveolar macrophages and damaged lung cells. Whether ATP serves a similar process during infection in the bovine lung is unknown. In the present study, we examined the effects of ATP treatment on the morphology, apoptosis, and permeability of bovine pulmonary epithelial (BPE) cells and bovine pulmonary microvascular endothelial cells (BPMEC). Monolayers of BPE cells underwent striking morphological changes when exposed to ATP that included separation of the cells. Neither BPE cells nor BPMEC exhibited increased apoptosis in response to ATP. BPE cell and BPMEC monolayers displayed virtually identical increases in permeability when exposed to ATP, with a 50% change occurring within the first hour of exposure. Both cell types contained mRNA for the P2X7receptor, a known receptor for ATP. In BPE cells, but not BPMEC, the change in permeability in response to ATP was reversed by the addition of a P2X7receptor antagonist. If similar permeability changes occur in vivo, they could be a factor in vascular leakage into lung airspaces during pneumonia.
Flagellin-F1-V Fusion Protein Is an Effective Plague Vaccine in Mice and Two Species of Nonhuman Primates
Authors: Mizel Steven B. , Graff Aaron H. , Sriranganathan Nammalwar , Ervin Sean , Lees Cynthia J. , Lively Mark O. , Hantgan Roy R. , Thomas Michael J. , Wood James , Bell Brian
Published: November 2008

A number of studies have clearly demonstrated that flagellin is a potent adjuvant that promotes robust immune responses when it is given with a protein antigen. In view of the potential biological and practical benefits of a recombinant protein vaccine composed of a single fusion protein containing flagellin and antigen, we have evaluated the efficacy of a fusion protein composed of flagellin and two protective antigens ofYersinia pestis(F1 and V) in eliciting protection against respiratory challenge withY. pestis. Flagellin-F1-V was produced and purified in high yield under good manufacturing practices conditions. The fusion protein retains full Toll-like receptor 5-stimulating activity in vitro. Using a prime-boost immunization protocol, we found that flagellin-F1-V elicits robust antigen-specific humoral immunity in mice and two species of nonhuman primates. Immune mice were fully protected against intranasal challenge with 150 mean tolerated doses ofY. pestisCO92. In immune mice, the bacteria were completely cleared within 3 days after challenge. Flagellin-F1-V exhibited full stability for at least 297 days at 4°C and at least 168 days at 25°C. At between 29 and 84 days at 37°C, the protein exhibited a loss of biological activity that appeared to be associated with a substantial change in protein diameter, possibly due to oligomerization. On the basis of our results, we believe that flagellin-F1-V is an outstanding candidate for evaluation in studies with humans.
Identification of
Candida albicans
and
Candida glabrata
within 1.5 Hours Directly from Positive Blood Culture Bottles with a Shortened Peptide Nucleic Acid Fluorescence In Situ Hybridization Protocol
Authors: Gherna Michael , Merz William G.
Published: November 2008

Candida albicans
and
Candida glabrata
can be identified in blood culture bottles within 2.5 h using peptide nucleic acid fluorescence in situ hybridization. A 1.25-h protocol was compared to the standard with 40 positive (clinical and spiked) blood culture bottles tested in batches of 5. All
C. albicans
(15) and
C. glabrata
(16) isolates, alone or mixed, were identified correctly using both protocols, whereas 18 isolates (five other species) were negative by both protocols. This shortened method will significantly reduce the time to identification.
Molecular Epidemiology of
Candida albicans
and Its Closely Related Yeasts
Candida dubliniensis
and
Candida africana
Authors: Romeo Orazio , Criseo Giuseppe
Published: November 2008

We performed a molecular study to determine the occurrence of
Candida albicans, Candida africana
, and
Candida dubliniensis
in different clinical samples. The study provides new insights into the epidemiology of candidiasis in hospitalized patients in three hospitals in southern Italy. It also reports the first detailed epidemiological data concerning the occurrence of
C. africana
in clinical samples.
Intrafamilial Transmission and Family-Specific Spectra of Cutaneous Betapapillomaviruses
Authors: Weissenborn S. J. , De Koning M. N. C. , Wieland U. , Quint W. G. V. , Pfister H. J.
Published: November 2008

Cutaneous human betapapillomaviruses (beta-HPVs) are widespread in the general population and have been associated with skin cancer. To evaluate the impact of continuous person-to-person contact within families on an individual's beta-HPV type spectrum, we collected serial skin swab samples from parents and children from 10 families. All participants were found to be beta-HPV DNA positive, with 1 to 13 types at study entry (median, 4.0 types). Initial and cumulative (2 to 16 types) HPV type multiplicities varied widely between different families but only a little between family members. The high intrafamilial correlation of HPV multiplicity is already obvious for babies aged 10 days to 10 months. Family members typically displayed similar spectra of HPV types. More than 75% of the HPV types in babies were also detected in their parents. This indicates that HPV transmission mainly results from close contact between family members. Type-specific persistence for at least 9 months was more prevalent in parents (92%) than in children (66%). Of the types detected throughout the study, 24% turned out to persist in the parents and only 11% in the children. Interestingly, about one-half of the HPV types found to persist in one of the parents occurred less frequently or even only sporadically in the spouse. Similarly, only one-third of the persisting parental types also persisted in their children. This indicates that even regular exposure to cutaneous HPV does not necessarily lead to the establishment of a persistent infection, which may point to type-specific susceptibilities of different individuals.
Differential Expression of the CXCR3 Ligands in Chronic Hepatitis C Virus (HCV) Infection and Their Modulation by HCV In Vitro
Authors: Helbig Karla J. , Ruszkiewicz Andrew , Lanford Robert E. , Berzsenyi Mark D. , Harley Hugh A. , McColl Shaun R. , Beard Michael R.
Published: November 2008

To investigate chemokine expression networks in chronic hepatitis C virus (HCV) infection, we used microarray analysis to determine chemokine expression in human infection and in chimpanzees experimentally infected with HCV. The CXCR3 chemokine family was highly expressed in both human and chimpanzee infection. CXCL10 was the only CXCR3 chemokine elevated in the serum, suggesting that it may neutralize any CXCR3 chemokine gradient established between the periphery and liver by CXCL11 and CXCL9. Thus, CXCR3 chemokines may not be responsible for recruitment of T lymphocytes but may play a role in positioning these cells within the liver. The importance of the CXCR3 chemokines, in particular CXCL11, was highlighted by replicating HCV (JFH-1) to selectively upregulate its expression in response to gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). This selective upregulation was confirmed at the transcriptional level by using the CXCL11 promoter driving the luciferase reporter gene. This synergistic increase in expression was not a result of HCV protein expression but the nonspecific innate response to double-stranded RNA (dsRNA), as both in vitro-transcribed HCV RNA and the dsRNA analogue poly(I:C) increased CXCL11 expression and promoter activity. Furthermore, we show that CXCL11 is an IRF3 (interferon regulatory factor 3) response gene whose expression is selectively enhanced by IFN-γ and TNF-α. In conclusion, the CXCR3 chemokines are the most significantly expressed chemokines in chronic hepatitis C and most likely play a role in positioning T cells in the liver. Furthermore, HCV can selectively increase CXCL11 expression in response to IFN-γ and TNF-α stimulation that may play a role in the pathogenesis of HCV-related liver disease.
Classical Swine Fever Virus Can Remain Virulent after Specific Elimination of the Interferon Regulatory Factor 3-Degrading Function of N
pro
Authors: Ruggli Nicolas , Summerfield Artur , Fiebach Ana R. , Guzylack-Piriou Laurence , Bauhofer Oliver , Lamm Catherine G. , Waltersperger Sandro , Matsuno Keita , Liu Luzia , Gerber Markus , Choi Kyung H. , Hofmann Martin A. , Sakoda Yoshihiro , Tratschin Jon-Duri
Published: November 2008

Pestiviruses prevent alpha/beta interferon (IFN-α/β) production by promoting proteasomal degradation of interferon regulatory factor 3 (IRF3) by means of the viral N
pro
nonstructural protein. N
pro
is also an autoprotease, and its amino-terminal coding sequence is involved in translation initiation. We previously showed with classical swine fever virus (CSFV) that deletion of the entire N
pro
gene resulted in attenuation in pigs. In order to elaborate on the role of the N
pro
-mediated IRF3 degradation in classical swine fever pathogenesis, we searched for minimal amino acid substitutions in N
pro
that would specifically abrogate this function. Our mutational analyses showed that degradation of IRF3 and autoprotease activity are two independent but structurally overlapping functions of N
pro
. We describe two mutations in N
pro
that eliminate N
pro
-mediated IRF3 degradation without affecting the autoprotease activity. We also show that the conserved standard sequence at these particular positions is essential for N
pro
to interact with IRF3. Surprisingly, when these two mutations are introduced independently in the backbones of highly and moderately virulent CSFV, the resulting viruses are not attenuated, or are only partially attenuated, in 8- to 10-week-old pigs. This contrasts with the fact that these mutant viruses have lost the capacity to degrade IRF3 and to prevent IFN-α/β induction in porcine cell lines and monocyte-derived dendritic cells. Taken together, these results demonstrate that contrary to previous assumptions and to the case for other viral systems, impairment of IRF3-dependent IFN-α/β induction is not a prerequisite for CSFV virulence.
Induction of Neuronal and Tumor-Related Genes by Adenovirus Type 12 E1A
Authors: Guan Hancheng , Williams Jim F. , Ricciardi Robert P.
Published: November 2008

Adenovirus type 12 (Ad12) E1A protein (E1A-12) contains a unique 20-amino-acid spacer region between the second and third conserved regions. Substitution of a single amino acid in the spacer is able to abrogate Ad12 tumorigenesis. To investigate the function of the spacer, microarray analysis was performed on cells transformed by tumorigenic and nontumorigenic Ad12s that differ only by one amino acid in the spacer. Fewer than 0.8% of approximately 8,000 genes in the microarray exhibited differential expression of threefold and higher. Of these, more than half of the known genes with higher expression in the wild-type Ad12-transformed cells have neuronal-specific functions. Some of the other differentially expressed genes are involved in the regulation of the cell cycle, transcription, cell structure, and tumor invasiveness. Northern blot analyses of a subset of the neuronal genes, including Robo1, N-MYC, and α-internexin, confirmed their strong expression in multiple Ad12 tumorigenic cell lines. In contrast, these neuronal genes displayed only minor or negligible expression in cells transformed by spacer-mutated Ad12. Significantly, stable introduction of E1A-12 into nontumorigenic Ad5-transformed cells induced neuronal gene expression. We found that the neuron-restrictive silencer factor, which serves as a master repressor of neuronal genes, was inactivated in both Ad12- and Ad5-transformed cells via cytoplasmic retention, though only Ad12-transformed cells exhibited neuronal gene induction. Mutational analyses of the α-internexin promoter demonstrated that E1A-12-mediated neuronal gene induction further required the activation of neuronal promoter E-box elements. These results indicate that the spacer is involved in mediating neuronal and tumor-related genes.
Exosomes Packaging APOBEC3G Confer Human Immunodeficiency Virus Resistance to Recipient Cells
Authors: Khatua Atanu K. , Taylor Harry E. , Hildreth James E. K. , Popik Waldemar
Published: November 2008

The human cytidine deaminase APOBEC3G (A3G) is a part of a cellular defense system against human immunodeficiency virus type 1 (HIV-1) and other retroviruses. Antiretroviral activity of A3G can be severely blunted in the presence of the HIV-1 protein Vif. However, in some cells expressing the enzymatically active low-molecular-mass form of A3G, HIV-1 replication is restricted at preintegration steps, before accumulation of Vif. Here, we show that A3G can be secreted by cells in exosomes that confer resistance to both
vif
-defective and wild-type HIV-1 in exosome recipient cells. Our results also suggest that A3G is the major exosomal component responsible for the anti-HIV-1 activity of exosomes. However, enzymatic activity of encapsidated A3G does not correlate with the observed limited cytidine deamination in HIV-1 DNA, suggesting that A3G-laden exosomes restrict HIV-1 through a nonenzymatic mechanism. Real-time PCR quantitation demonstrated that A3G exosomes reduce accumulation of HIV-1 reverse transcription products and steady-state levels of HIV-1 Gag and Vif proteins. Our findings suggest that A3G exosomes could be developed into a novel class of anti-HIV-1 therapeutics.
Enhanced Induction of Intestinal Cellular Immunity by Oral Priming with Enteric Adenovirus 41 Vectors
Authors: Ko Sung-Youl , Cheng Cheng , Kong Wing-Pui , Wang Lingshu , Kanekiyo Masaru , Einfeld David , King C. Richter , Gall Jason G. D. , Nabel Gary J.
Published: November 2008

Human immunodeficiency virus type 1 (HIV-1) infection is characterized by the rapid onset of intestinal T-cell depletion that initiates the progression to AIDS. The induction of protective immunity in the intestinal mucosa therefore represents a potentially desirable feature of a preventive AIDS vaccine. In this study, we have evaluated the ability of an enteric adenovirus, recombinant adenovirus 41 (rAd41), to elicit intestinal and systemic immune responses by different immunization routes, alone or in combination with rAd5. rAd41 expressing HIV envelope (Env) protein induced cellular immune responses comparable to those of rAd5-based vectors after either a single intramuscular injection or a DNA prime/rAd boost. Oral priming with rAd41-Env followed by intramuscular boosting with rAd5-Env stimulated a more potent CD8
+
T-cell response in the small intestine than the other immunization regimens. Furthermore, the direct injection of rAd41-Env into ileum together with intramuscular rAd5-Env boosting increased Env-specific cellular immunity markedly in mucosal as well as systemic compartments. These data demonstrate that heterologous rAd41 oral or ileal priming with rAd5 intramuscular boosting elicits enhanced intestinal mucosal cellular immunity and that oral or ileal vector delivery for primary immunization facilitates the generation of mucosal immunity.
Analysis of Influenza B Virus NS1 Protein Trafficking Reveals a Novel Interaction with Nuclear Speckle Domains
Authors: Schneider Jana , Dauber Bianca , Melén Krister , Julkunen Ilkka , Wolff Thorsten
Published: November 2008

Many proteins that function in the transcription, maturation, and export of metazoan mRNAs are concentrated in nuclear speckle domains, indicating that the compartment is important for gene expression. Here, we show that the NS1 protein of influenza B virus (B/NS1) accumulates in nuclear speckles and causes rounding and morphological changes of the domains, indicating a disturbance in their normal functions. This property was located within the N-terminal 90 amino acids of the B/NS1 protein and was shown to be independent of any other viral gene product. Within this protein domain, we identified a monopartite importin α binding nuclear localization signal. Reverse-genetic analysis of this motif indicated that nuclear import and speckle association of the B/NS1 protein are required for the full replication capacity of the virus. In the late phase of virus infection, the B/NS1 protein relocated to the cytoplasm, which occurred in a CRM1-independent manner. The interaction of the B/NS1 protein with nuclear speckles may reflect a recruitment function to promote viral-gene expression. To our knowledge, this is the first functional description of a speckle-associated protein that is encoded by a negative-strand RNA virus.
Crystal Structures of Two Coronavirus ADP-Ribose-1″-Monophosphatases and Their Complexes with ADP-Ribose: a Systematic Structural Analysis of the Viral ADRP Domain
Authors: Xu Yuanyuan , Cong Le , Chen Cheng , Wei Lei , Zhao Qi , Xu Xiaoling , Ma Yanlin , Bartlam Mark , Rao Zihe
Published: November 2008

The coronaviruses are a large family of plus-strand RNA viruses that cause a wide variety of diseases both in humans and in other organisms. The coronaviruses are composed of three main lineages and have a complex organization of nonstructural proteins (nsp's). In the coronavirus, nsp3 resides a domain with the macroH2A-like fold and ADP-ribose-1"-monophosphatase (ADRP) activity, which is proposed to play a regulatory role in the replication process. However, the significance of this domain for the coronaviruses is still poorly understood due to the lack of structural information from different lineages. We have determined the crystal structures of two viral ADRP domains, from the group I human coronavirus 229E and the group III avian infectious bronchitis virus, as well as their respective complexes with ADP-ribose. The structures were individually solved to elucidate the structural similarities and differences of the ADRP domains among various coronavirus species. The active-site residues responsible for mediating ADRP activity were found to be highly conserved in terms of both sequence alignment and structural superposition, whereas the substrate binding pocket exhibited variations in structure but not in sequence. Together with data from a previous analysis of the ADRP domain from the group II severe acute respiratory syndrome coronavirus and from other related functional studies of ADRP domains, a systematic structural analysis of the coronavirus ADRP domains was realized for the first time to provide a structural basis for the function of this domain in the coronavirus replication process.
An Arginine Switch in the Species B Adenovirus Knob Determines High-Affinity Engagement of Cellular Receptor CD46
Authors: Persson B. David , Müller Steffen , Reiter Dirk M. , Schmitt Benedikt B. T. , Marttila Marko , Sumowski Chris Vanessa , Schweizer Sabine , Scheu Ulrike , Ochsenfeld Christian , Arnberg Niklas , Stehle Thilo
Published: November 2008

Adenoviruses (Ads) are icosahedral, nonenveloped viruses with a double-stranded DNA genome. The 51 known Ad serotypes exhibit profound variations in cell tropism and disease types. The number of observed Ad infections is steadily increasing, sometimes leading to fatal outcomes even in healthy individuals. Species B Ads can cause kidney infections, hemorrhagic cystitis, and severe respiratory infections, and most of them use the membrane cofactor protein CD46 as a cellular receptor. The crystal structure of the human Ad type 11 (Ad11) knob complexed with CD46 is known; however, the determinants of CD46 binding in related species B Ads remain unclear. We report here a structural and functional analysis of the Ad11 knob, as well as the Ad7 and Ad14 knobs, which are closely related in sequence to the Ad11 knob but have altered CD46-binding properties. The comparison of the structures of the three knobs, which we determined at very high resolution, provides a platform for understanding these differences and allows us to propose a mechanism for productive high-affinity engagement of CD46. At the center of this mechanism is an Ad knob arginine that needs to switch its orientation in order to engage CD46 with high affinity. Quantum chemical calculations showed that the CD46-binding affinity of Ad11 is significantly higher than that of Ad7. Thus, while Ad7 and Ad14 also bind CD46, the affinity and kinetics of these interactions suggest that these Ads are unlikely to use CD46 productively. The proposed mechanism is likely to determine the receptor usage of all CD46-binding Ads.
VP22 of Herpes Simplex Virus 1 Promotes Protein Synthesis at Late Times in Infection and Accumulation of a Subset of Viral mRNAs at Early Times in Infection
Authors: Duffy Carol , Mbong Ekaette F. , Baines Joel D.
Published: November 2008

VP22, encoded by the U
L
49 gene, is one of the most abundant proteins of the herpes simplex virus 1 (HSV-1) tegument. In the present study we show VP22 is required for optimal protein synthesis at late times in infection. Specifically, in the absence of VP22, viral proteins accumulated to wild-type levels until ∼6 h postinfection. At that time, ongoing synthesis of most viral proteins dramatically decreased in the absence of VP22, whereas protein stability was not affected. Of the individual proteins we assayed, VP22 was required for optimal synthesis of the late viral proteins gE and gD and the immediate-early protein ICP0 but did not have discernible effects on accumulation of the immediate-early proteins ICP4 or ICP27. In addition, we found VP22 is required for the accumulation of a subset of mRNAs to wild-type levels at early, but not late, times in infection. Specifically, the presence of VP22 enhanced the accumulation of gE and gD mRNAs until ∼9 h postinfection, but it had no discernible effect at later times in infection. Also, VP22 did not significantly affect ICP0 mRNA at any time in infection. Thus, the protein synthesis and mRNA phenotypes observed with the U
L
49-null virus are separable with regard to both timing during infection and the genes affected and suggest separate roles for VP22 in enhancing the accumulation of viral proteins and mRNAs. Finally, we show that VP22's effects on protein synthesis and mRNA accumulation occur independently of mutations in genes encoding the VP22-interacting partners VP16 and vhs.
Our future inheritance
Authors: Short R V
Published: November 2008

Two of the most important topics in the field of medical ethics today are insemination by donor(AID)andin-vitrofertilization. The conclusions of a working party set up by the British Association for the Advancement of Science are embodied in a small book reviewed on pate 108 of this issue, but we feel that more discussion than can be set out in the space allocated to book reviews is justified. Also, this journal in its first number has already devoted a group of papers to the issue of abortion, so the conclusions of the working party and our own comments overlap and we hope illuminate further the problems enunciated.
A critique of the Law Commission's report on injuries to unborn children and the proposed Congenital Disabilities (Civil Liability) Bill
Authors: Kennedy Ian , Edwards R G
Published: November 2008

The authors are members of the British Association Committee on Social Concern and Biological Advances. Following earlier discussions of legal and social problems arising from certain medical advances, they undertook, independently, to examine the Law Commission's study.
Why patients should keep their own records.
Authors: Coleman V
Published: November 2008

Too many people now have access to confidential medical information. Patients are becoming justifiably wary and the doctor-patient relationship is deteriorating. We can avert the developing crisis by allowing patients to keep their own medical records at home. This will ensure that confidentiality is respected and that patients continue to trust their doctors.