bluuebunny/crossref_metadata_2025 huggingface dataset:
Creating and using knowledge: an analysis of the differentiated nature of workplace learning environments
Authors: Fuller Alison , Unwin Lorna , Felstead Alan , Jewson Nick , Kakavelakis Konstantinos
Published: October 2007

This paper argues that contemporary workplaces give rise to many different forms of knowledge creation and use, and, as a consequence to different forms of learning and pedagogical approaches. Some of these are utilised to the benefit of the organisation and employees (though not, necessarily, in a reciprocal manner), but others are buried within everyday workplace activity. The discussion builds on earlier work where it was argued that organisations differ in the way they create and manage themselves as learning environments, with some conceptualised as ‘expansive’ in the sense that their employees experience diverse forms of participation and, hence, are more likely to foster learning at work. By studying the way in which work is organised (including the organisation of physical and virtual spaces), this research is suggesting that it is possible to expose some of this learning activity as well as to identify examples where new (or refined) knowledge has been created. In this regard, it is argued that it is important to break down conceptual hierarchies that presuppose that learning is restricted to certain types of employee and/or parts of an organisation and to re‐examine knowledge as applied to the workplace. The conclusion focuses on how such an approach, and in particular the use of a productive system analysis, is strengthening the concept of expansive and restrictive learning environments.
Research to practice—formal dissemination of the School Health and Alcohol Harm Reduction Project (SHAHRP) in Australia
Authors: MCBRIDE NYANDA T. , FARRINGDON FIONA H. , KENNEDY CAROL A.
Published: October 2007

Introduction and Aims. This paper discusses the formal dissemination of the School Health and Alcohol Harm Reduction Project (National SHAHRP Dissemination Project) in Australia. The original SHAHRP research programme (SHAHRP study) was assessed previously for effectiveness during a longitudinal research study which followed the student participants over 32 months post‐intervention. The SHAHRP study focused on evaluating the behavioural impact of the programme and the results indicated that wider dissemination would be of value. Design and Methods. The National SHAHRP Dissemination Project involved key decision makers of drug education in the Government, Catholic and Independent schools sectors, in targeted states, agreeing to disseminate the SHAHRP Project through teacher educators and teachers in their sector and regions. Process, reach and project satisfaction were assessed. Results. The Dissemination Project conducted two workshops for 35 teacher educators. Fifteen teacher educators subsequently conducted 21 workshops for teachers between August 2003 and June 2004. One hundred and seventy schools and nearly 300 (294) teachers were involved in this training. Discussion and Conclusions. The advantages and barriers of researcher‐led dissemination, as illustrated in this study, suggest that methods other than publication in scientific journals and presentation at conferences may be useful for the transfer of effective intervention research programmes to practice. There may be some benefit to identifying and testing other research‐initiated pathways leading to evidence‐based policy and practice which, in combination with practitioner‐led transfer, can help to bridge the gap between research and practice in the future.
The creation of evidence in ‘evidence‐based’ drug prevention: a critique of the Strengthening Families Program Plus Life Skills Training evaluation
Authors: GORMAN D. M. , CONDE E. , HUBER J. C.
Published: October 2007

School‐based curricula have become a mainstay of drug prevention policy in the United States and are increasing in popularity in other parts of the world. The promotion and dissemination of these interventions has been driven in large part by the creation of lists of programmes which, it is claimed, are grounded in scientific evidence demonstrating their effectiveness. Recently concerns have been raised about the data analysis and presentation practices used in evaluations of a number of programmes that appear on these lists. Here we examine a series of papers from an evaluation of an intervention that combined the Strengthening Families Program 10–14 and Life Skills Training Program, each of which is among the most widely advocated universal drug prevention programmes. The data analysis and presentation practices employed in the evaluation of this combined programme include one‐tailed significance testing, alpha levels of 0.10, changes in outcome variables across publications and use of the post‐test data as the baseline when assessing change over time. Taken together, these practices severely limit the claims that can be made about the results presented in the evaluation. Specifically, we believe that far from supporting the evaluators' claims concerning the rigour of the findings and their generalisability and public health significance, the results are very fragile, of little practical significance and quite possibly analysis‐dependent.
Replacing ineffective early alcohol/drug education in the United States with age‐appropriate adolescent programmes and assistance to problematic users
Authors: SKAGER RODNEY
Published: October 2007

Issues. Despite more than a decade of federal sponsorship of ‘evidence‐based’ alcohol/drug education, there has been no consistent downward trend in overall prevalence among youth over the past 15 years. Reasons underlying this situation are examined. Approach. Published technical critiques of initial research supporting widely used evidence‐based programs are reviewed along with replication studies conducted later by independent researchers not associated with initial program development. Social and institutional barriers in the US against changes in AOD policy and practice for young people are also suggested. Key Findings. Emerging use of diverted pharmaceuticals (now second to cannabis in prevalence) may underlie moderate recent decline in use of alcohol. Early federal certification standards for ‘evidence based’ prevention education have been seriously compromised. Technical critiques of initial evaluations and negative replication studies of these programs are consistent with lack of impact. Finally, fidelity of implementation in regular school settings is commonly flawed. Implications. Failure of these mainly pre‐secondary educational programs may underlie recent federal support for forced random AOD testing of secondary school students. A new approach to drug education for adolescent students seems warranted as a positive alternative to personally intrusive surveillance. Conclusion. An interactive approach at the secondary school level that incorporates an age‐appropriate educational process is proposed. While advising abstinence, this approach also facilitates identifying and assisting problematic AOD users.
Harmful effects of alcohol on sexual behaviour in a New Zealand university community
Authors: CASHELL‐SMITH MARTINE L. , CONNOR JENNIE L. , KYPRI KYPROS
Published: October 2007

Introduction and Aims. The prevalence of hazardous drinking among university students in New Zealand is very high, but the impacts on sexual behaviour are largely unknown. The aim of this study was to estimate the prevalence and correlates of alcohol‐related risky and unwanted sexual experiences. Methods. We conducted a web‐based survey of a random sample of university students, asking about specific experiences resulting from their own drinking or the drinking of others, and some beliefs about drinking. Results. A total of 1564 students responded (82%) and the following were reported as the result of drinking, by women and men respectively, in the last 3 months: unprotected sex 11% and 15%; sex they were not happy with at the time 6% and 7%; sex later regretted 16% and 19%. Also, 34% of women and 25% of men reported unwanted sexual advances in the past 4 weeks as a result of other people's drinking. These experiences were all associated positively with Alcohol Use Disorders Identification Test (AUDIT) scores of the respondents, certain types of living arrangements and specific attitudes to drinking. In addition, 1% of women and 0.5% of men reported sexual assault in the past 4 weeks. Discussion and Conclusions. Interventions to reduce alcohol‐related risky sexual behaviours should target both male and female drinkers and identifiable subgroups at higher risk. Prevention policy should also address the high levels of availability and promotion of alcohol in the campus environment.
Does harm minimisation lead to greater experimentation? Results from a school smoking intervention trial
Authors: HAMILTON GREG , CROSS DONNA , RESNICOW KEN , SHAW THERESE
Published: October 2007

Introduction and Aims. Declines in adolescent smoking prevalence have slowed recently, resulting in increased interest and literature in tobacco harm minimisation. To date, harm reduction strategies have focused largely on modifying the product and alternative (safer) mechanisms of nicotine delivery. There has been little exploration of primary harm minimisation to prevent the onset of regular smoking among young people. A major concern expressed about harm reduction interventions and young people is that they may increase experimentation among non‐users. Design and Methods. The Smoking Cessation for Youth Project was a 2‐year school‐based cluster randomised controlled trial conducted in 30 Western Australian schools. Results on the primary outcome showed a significant reduction in regular smoking among 4636 13–15‐year‐olds receiving a harm minimisaton versus standard intervention. This paper addresses the intervention effects on 2078 students who had not smoked at baseline. Results. At 20‐month follow‐up, smoking initiation was slightly lower among intervention students than comparison students (who received a largely abstinence‐based intervention), although this difference did not attain statistical significance (OR = 0.86; 95% confidence interval: 0.68, 1.09). Discussion and Conclusions. This study provided limited evidence to suggest that harm minimisation is a superior approach to abstinence‐based interventions for non‐smokers. However, this intervention did not contribute to increased experimentation among non‐smokers. Although more trials are required, these results indicate that fears of potential negative iatrogenic effects from school‐based harm minimisation interventions may be unwarranted.
Implementation evaluation of the Blueprint multi‐component drug prevention programme: fidelity of school component delivery
Authors: STEAD MARTINE , STRADLING ROBERT , MACNEIL MORAG , MACKINTOSH ANNE MARIE , MINTY SARAH
Published: October 2007

In order to achieve their desired aims, evidence‐based, theory‐driven drug education programmes need to be implemented as intended. Measurement of ‘fidelity of implementation’ is now included increasingly as part of programme evaluation, although measures and methods are sometimes limited. A more sophisticated approach to assessing implementation fidelity, based on Dane & Schneider's (1998) five dimensions, was used to examine the classroom curriculum element of the Blueprint programme. Blueprint was the largest and most rigorous evaluation of a multi‐component drug prevention programme to date in the United Kingdom. Lessons were, overall, delivered with reasonable fidelity, although teachers did not always understand the thinking behind particular activities, suggesting that training needs to focus not only on content and methods but why particular approaches are important. Different dimensions of fidelity could conflict with one another: under pressure of time, generic elements and processes designed to reflect on learning were sometimes sacrificed in order that core drug education activities could be completed. Future drug education curricula need to build in more flexibility for discussion without compromising core evidence‐based elements. Even with substantial training and support, individual variations in delivery were found, although few differences were found between teachers with prior expertise and teachers new to drug education. The methods and measures applied in the Blueprint study all represent attempts to improve on previous measures in terms of both reliability and sensitivity. In this respect the Blueprint study represents a valuable contribution to the science of implementation fidelity.
Junying Yuan: Changing avenues without losing focus
Authors: LeBrasseur Nicole
Published: October 2007

An interest in neurodegenerative diseases drove Junying Yuan to study cell death as a graduate student at Harvard University. Now a full professor at the hallowed institute, Yuan is moved by the same interest in a new direction—the removal of misfolded proteins.
Necdin mediates skeletal muscle regeneration by promoting myoblast survival and differentiation
Authors: Deponti Daniela , François Stéphanie , Baesso Silvia , Sciorati Clara , Innocenzi Anna , Broccoli Vania , Muscatelli Françoise , Meneveri Raffaella , Clementi Emilio , Cossu Giulio , Brunelli Silvia
Published: October 2007

Regeneration of muscle fibers that are lost during pathological muscle degeneration or after injuries is sustained by the production of new myofibers. An important cell type involved in muscle regeneration is the satellite cell. Necdin is a protein expressed in satellite cell–derived myogenic precursors during perinatal growth. However, its function in myogenesis is not known. We compare transgenic mice that overexpress necdin in skeletal muscle with both wild-type and necdin null mice. After muscle injury the necdin null mice show a considerable defect in muscle healing, whereas mice that overexpress necdin show a substantial increase in myofiber regeneration. We also find that in muscle, necdin increases myogenin expression, accelerates differentiation, and counteracts myoblast apoptosis. Collectively, these data clarify the function and mechanism of necdin in skeletal muscle and show the importance of necdin in muscle regeneration.
The motor activity of myosin-X promotes actin fiber convergence at the cell periphery to initiate filopodia formation
Authors: Tokuo Hiroshi , Mabuchi Katsuhide , Ikebe Mitsuo
Published: October 2007

Filopodia are actin-rich fingerlike protrusions found at the leading edge of migrating cells and are believed to play a role in directional sensing. Previous studies have shown that myosin-X (myoX) promotes filopodia formation and that this is mediated through its ability to deliver specific cargoes to the cell periphery (Tokuo, H., and M. Ikebe. 2004. Biochem Biophys. Commun. 319:214–220; Zhang, H., J.S. Berg, Z. Li, Y. Wang, P. Lang, A.D. Sousa, A. Bhaskar, R.E. Cheney, and S. Stromblad. 2004. Nat. Cell Biol. 6:523–531; Bohil, A.B., B.W. Robertson, and R.E. Cheney. 2006. Proc. Natl. Acad. Sci. USA. 103:12411–12416; Zhu, X.J., C.Z. Wang, P.G. Dai, Y. Xie, N.N. Song, Y. Liu, Q.S. Du, L. Mei, Y.Q. Ding, and W.C. Xiong. 2007. Nat. Cell Biol. 9:184–192). In this study, we show that the motor function of myoX and not the cargo function is critical for initiating filopodia formation. Using a dimer-inducing technique, we find that myoX lacking its cargo-binding tail moves laterally at the leading edge of lamellipodia and induces filopodia in living cells. We conclude that the motor function of the two-headed form of myoX is critical for actin reorganization at the leading edge, leading to filopodia formation.
Telomerase reverses epidermal hair follicle stem cell defects and loss of long-term survival associated with critically short telomeres
Authors: Siegl-Cachedenier Irene , Flores Ignacio , Klatt Peter , Blasco Maria A.
Published: October 2007

Organ homeostasis and organismal survival are related to the ability of stem cells to sustain tissue regeneration. As a consequence of accelerated telomerase shortening, telomerase-deficient mice show defective tissue regeneration and premature death. This suggests a direct impact of telomere length and telomerase activity on stem cell biology. We recently found that short telomeres impair the ability of epidermal stem cells to mobilize out of the hair follicle (HF) niche, resulting in impaired skin and hair growth and in the suppression of epidermal stem cell proliferative capacity in vitro. Here, we demonstrate that telomerase reintroduction in mice with critically short telomeres is sufficient to correct epidermal HF stem cell defects. Additionally, telomerase reintroduction into these mice results in a normal life span by preventing degenerative pathologies in the absence of increased tumorigenesis.
Novel cargo-binding site in the β and δ subunits of coatomer
Authors: Michelsen Kai , Schmid Volker , Metz Jutta , Heusser Katja , Liebel Urban , Schwede Torsten , Spang Anne , Schwappach Blanche
Published: October 2007

Arginine (R)-based ER localization signals are sorting motifs that confer transient ER localization to unassembled subunits of multimeric membrane proteins. The COPI vesicle coat binds R-based signals but the molecular details remain unknown. Here, we use reporter membrane proteins based on the proteolipid Pmp2 fused to GFP and allele swapping of COPI subunits to map the recognition site for R-based signals. We show that two highly conserved stretches—in the β- and δ-COPI subunits—are required to maintain Pmp2GFP reporters exposing R-based signals in the ER. Combining a deletion of 21 residues in δ-COP together with the mutation of three residues in β-COP gave rise to a COPI coat that had lost its ability to recognize R-based signals, whilst the recognition of C-terminal di-lysine signals remained unimpaired. A homology model of the COPI trunk domain illustrates the recognition of R-based signals by COPI.
Rac1 and Rac2 differentially regulate actin free barbed end formation downstream of the fMLP receptor
Authors: Sun Chun Xiang , Magalhães Marco A.O. , Glogauer Michael
Published: October 2007

Actin assembly at the leading edge of migrating cells depends on the availability of high-affinity free barbed ends (FBE) that drive actin filament elongation and subsequent membrane protrusion. We investigated the specific mechanisms through which the Rac1 and Rac2 small guanosine triphosphatases (GTPases) generate free barbed ends in neutrophils. Using neutrophils lacking either Rac1 or Rac2 and a neutrophil permeabilization model that maintains receptor signaling to the actin cytoskeleton, we assessed the mechanisms through which these two small GTPases mediate FBE generation downstream of the formyl-methionyl-leucyl-phenylalanine receptor. We demonstrate here that uncapping of existing barbed ends is mediated through Rac1, whereas cofilin- and ARP2/3-mediated FBE generation are regulated through Rac2. This unique combination of experimental tools has allowed us to identify the relative roles of uncapping (15%), cofilin severing (10%), and ARP2/3 de novo nucleation (75%) in FBE generation and the respective roles played by Rac1 and Rac2 in mediating actin dynamics.
KRIT-1/CCM1 is a Rap1 effector that regulates endothelial cell–cell junctions
Authors: Glading Angela , Han Jaewon , Stockton Rebecca A. , Ginsberg Mark H.
Published: October 2007

Cerebral cavernous malformation (CCM), a disease associated with defective endothelial junctions, result from autosomal dominant CCM1 mutations that cause loss of KRIT-1 protein function, though how the loss of KRIT-1 leads to CCM is obscure. KRIT-1 binds to Rap1, a guanosine triphosphatase that maintains the integrity of endothelial junctions. Here, we report that KRIT-1 protein is expressed in cultured arterial and venous endothelial cells and is present in cell–cell junctions. KRIT-1 colocalized and was physically associated with junctional proteins via its band 4.1/ezrin/radixin/moesin (FERM) domain. Rap1 activity regulated the junctional localization of KRIT-1 and its physical association with junction proteins. However, the association of the isolated KRIT-1 FERM domain was independent of Rap1. Small interfering RNA–mediated depletion of KRIT-1 blocked the ability of Rap1 to stabilize endothelial junctions associated with increased actin stress fibers. Thus, Rap1 increases KRIT-1 targeting to endothelial cell–cell junctions where it suppresses stress fibers and stabilizes junctional integrity.
Differences between homologous alleles of olfactory receptor genes require the Polycomb Group protein Eed
Authors: Alexander Mary Kate , Mlynarczyk-Evans Susanna , Royce-Tolland Morgan , Plocik Alex , Kalantry Sundeep , Magnuson Terry , Panning Barbara
Published: October 2007

Anumber of mammalian genes are expressed from only one of the two homologous chromosomes, selected at random in each cell. These include genes subject to X-inactivation, olfactory receptor (OR) genes, and several classes of immune system genes. The means by which monoallelic expression is established are only beginning to be understood. Using a cytological assay, we show that the two homologous alleles of autosomal random monoallelic loci differ from each other in embryonic stem (ES) cells, before establishment of monoallelic expression. The Polycomb Group gene Eed is required to establish this distinctive behavior. In addition, we found that when Eed mutant ES cells are differentiated, they fail to establish asynchronous replication timing at OR loci. These results suggest a common mechanism for random monoallelic expression on autosomes and the X chromosome, and implicate Eed in establishing differences between homologous OR loci before and after differentiation.
The receptor guanylyl cyclase Npr2 is essential for sensory axon bifurcation within the spinal cord
Authors: Schmidt Hannes , Stonkute Agne , Jüttner René , Schäffer Susanne , Buttgereit Jens , Feil Robert , Hofmann Franz , Rathjen Fritz G.
Published: October 2007

Sensory axonal projections into the spinal cord display a highly stereotyped pattern of T- or Y-shaped axon bifurcation at the dorsal root entry zone (DREZ). Here, we provide evidence that embryonic mice with an inactive receptor guanylyl cyclase Npr2 or deficient for cyclic guanosine monophosphate–dependent protein kinase I (cGKI) lack the bifurcation of sensory axons at the DREZ, i.e., the ingrowing axon either turns rostrally or caudally. This bifurcation error is maintained to mature stages. In contrast, interstitial branching of collaterals from primary stem axons remains unaffected, indicating that bifurcation and interstitial branching are processes regulated by a distinct molecular mechanism. At a functional level, the distorted axonal branching at the DREZ is accompanied by reduced synaptic input, as revealed by patch clamp recordings of neurons in the superficial layers of the spinal cord. Hence, our data demonstrate that Npr2 and cGKI are essential constituents of the signaling pathway underlying axonal bifurcation at the DREZ and neuronal connectivity in the dorsal spinal cord.
Cep164, a novel centriole appendage protein required for primary cilium formation
Authors: Graser Susanne , Stierhof York-Dieter , Lavoie Sébastien B. , Gassner Oliver S. , Lamla Stefan , Le Clech Mikael , Nigg Erich A.
Published: October 2007

Primary cilia (PC) function as microtubule-based sensory antennae projecting from the surface of many eukaryotic cells. They play important roles in mechano- and chemosensory perception and their dysfunction is implicated in developmental disorders and severe diseases. The basal body that functions in PC assembly is derived from the mature centriole, a component of the centrosome. Through a small interfering RNA screen we found several centrosomal proteins (Ceps) to be involved in PC formation. One newly identified protein, Cep164, was indispensable for PC formation and hence characterized in detail. By immunogold electron microscopy, Cep164 could be localized to the distal appendages of mature centrioles. In contrast to ninein and Cep170, two components of subdistal appendages, Cep164 persisted at centrioles throughout mitosis. Moreover, the localizations of Cep164 and ninein/Cep170 were mutually independent during interphase. These data implicate distal appendages in PC formation and identify Cep164 as an excellent marker for these structures.
Detuning CD8 T cells: down-regulation of CD8 expression, tetramer binding, and response during CTL activation
Authors: Xiao Zhengguo , Mescher Matthew F. , Jameson Stephen C.
Published: October 2007

CD8 is critical for T cell recognition of peptide/class I major histocompatability complex ligands, yet is down-regulated during activation of CD8 T cells. We report that loss of CD8 expression early during in vivo responses to vaccinia virus or Listeria monocytogenes (LM) correlates with decreased T cell staining with specific class I/peptide tetramers and reduced CD8 T cell sensitivity for antigen. Loss of CD8 cell surface expression occurs despite sustained mRNA expression, and CD8 levels return to normal levels during differentiation of memory cells, indicating a transient effect. We determined that during response to LM, CD8 down-regulation is regulated by T cell reactivity to type I interferon (IFN-I) because CD8 loss was averted on IFN-I receptor–deficient T cells. IFN-I alone was not sufficient to drive CD8 down-regulation, however, as antigen was also required for CD8 loss. These results suggest that CD8 effector T cell differentiation involves a transient down-regulation of antigen sensitivity (CTL “detuning”), via reduced CD8 expression, a feature that may focus the effector response on target cells expressing high levels of antigen (e.g., infected cells), while limiting collateral damage to bystander cells.
T cell activation enhancement by endogenous pMHC acts for both weak and strong agonists but varies with differentiation state
Authors: Yachi Pia P. , Lotz Carina , Ampudia Jeanette , Gascoigne Nicholas R.J.
Published: October 2007

T cells are extremely sensitive in their ability to find minute amounts of antigenic peptide in the midst of many endogenous peptides presented on an antigen-presenting cell. The role of endogenous peptides in the recognition of foreign peptide and hence in T cell activation has remained controversial for CD8+ T cell activation. We showed previously that in a CD8+ T cell hybridoma, nonstimulatory endogenous peptides enhance T cell sensitivity to antigen by increasing the coreceptor function of CD8. However, others were not able to detect such enhancement in naive and activated CD8+ T cells. Here, we show that endogenous peptides substantially enhance the ability of T cells to detect antigen, an effect measurable by up-regulation of activation or maturation markers and by increased effector function. This enhancement is most pronounced in thymocytes, moderate in naive T cells, and mild in effector T cells. The importance of endogenous peptides is inversely proportional to the agonist activity of the stimulatory peptide presented. Unlike for CD4+ T cells, the T cell receptor of CD8+ T cells does not distinguish between endogenous peptides for their ability to enhance antigen recognition.
LPS-induced down-regulation of signal regulatory protein α contributes to innate immune activation in macrophages
Authors: Kong Xiao-Ni , Yan He-Xin , Chen Lei , Dong Li-Wei , Yang Wen , Liu Qiong , Yu Le-Xing , Huang Dan-Dan , Liu Shu-Qin , Liu Hui , Wu Meng-Chao , Wang Hong-Yang
Published: October 2007

Activation of the mitogen-activated protein kinases (MAPKs) and nuclear factor κB (NF-κB) cascades after Toll-like receptor (TLR) stimulation contributes to innate immune responses. Signal regulatory protein (SIRP) α, a member of the SIRP family that is abundantly expressed in macrophages, has been implicated in regulating MAPK and NF-κB signaling pathways. In addition, SIRPα can negatively regulate the phagocytosis of host cells by macrophages, indicating an inhibitory role of SIRPα in innate immunity. We provide evidences that SIRPα is an essential endogenous regulator of the innate immune activation upon lipopolysaccharide (LPS) exposure. SIRPα expression was promptly reduced in macrophages after LPS stimulation. The decrease in SIRPα expression levels was required for initiation of LPS-induced innate immune responses because overexpression of SIRPα reduced macrophage responses to LPS. Knockdown of SIRPα caused prolonged activation of MAPKs and NF-κB pathways and augmented production of proinflammatory cytokines and type I interferon (IFN). Mice transferred with SIRPα-depleted macrophages were highly susceptible to endotoxic shock, developing multiple organ failure and exhibiting a remarkable increase in mortality. SIRPα may accomplish this mainly through its association and sequestration of the LPS signal transducer SHP-2. Thus, SIRPα functions as a biologically important modulator of TLR signaling and innate immunity.
Adjuvanting a DNA vaccine with a TLR9 ligand plus Flt3 ligand results in enhanced cellular immunity against the simian immunodeficiency virus
Authors: Kwissa Marcin , Amara Rama R. , Robinson Harriet L. , Moss Bernard , Alkan Sefik , Jabbar Abdul , Villinger Francois , Pulendran Bali
Published: October 2007

DNA vaccines offer promising strategies for immunization against infections. However, their clinical use requires improvements in immunogenicity. We explored the efficacy of Toll-like receptor (TLR) ligands (TLR-Ls) on augmenting the immunogenicity of a DNA prime–modified vaccinia virus Ankara (MVA) boost vaccine against SIV. Rhesus macaques were injected with Fms-like tyrosine kinase 3 (Flt3)–ligand (FL) to expand dendritic cells (DCs) and were primed with a DNA vaccine encoding immunodeficiency virus antigens mixed with ligands for TLR9 or TLR7/8. Subsequently, the animals were boosted with DNA and twice with recombinant MVA expressing the same antigens. TLR9-L (CpG DNA) mediated activation of DCs in vivo and enhanced the magnitude of antigen-specific CD8+ interferon (IFN) γ+ T cells and polyfunctional CD8+ T cells producing IFN-γ, tumor necrosis factor α, and interleukin 2. Although this trial was designed primarily as an immunogenicity study, we challenged the animals with pathogenic SIVmac251 and observed a reduction in peak viremia and cumulative viral loads in the TLR9-L plus FL-adjuvanted group relative to the unvaccinated group; however, the study design precluded comparisons between the adjuvanted groups and the group vaccinated with DNA/MVA alone. Viral loads were inversely correlated with the magnitude and quality of the immune response. Thus, the immunogenicity of DNA vaccines can be augmented with TLR9-L plus FL.
AIDS virus–specific CD8+ T lymphocytes against an immunodominant cryptic epitope select for viral escape
Authors: Maness Nicholas J. , Valentine Laura E. , May Gemma E. , Reed Jason , Piaskowski Shari M. , Soma Taeko , Furlott Jessica , Rakasz Eva G. , Friedrich Thomas C. , Price David A. , Gostick Emma , Hughes Austin L. , Sidney John , Sette Alessandro , Wilson Nancy A. , Watkins David I.
Published: October 2007

Cryptic major histocompatibility complex class I epitopes have been detected in several pathogens, but their importance in the immune response to AIDS viruses remains unknown. Here, we show that Mamu-B*17+ simian immunodeficiency virus (SIV)mac239-infected rhesus macaques that spontaneously controlled viral replication consistently made strong CD8+ T lymphocyte (CD8-TL) responses against a cryptic epitope, RHLAFKCLW (cRW9). Importantly, cRW9-specific CD8-TL selected for viral variation in vivo and effectively suppressed SIV replication in vitro, suggesting that they might play a key role in the SIV-specific response. The discovery of an immunodominant CD8-TL response in elite controller macaques against a cryptic epitope suggests that the AIDS virus–specific cellular immune response is likely far more complex than is generally assumed.
New lane in the information highway: alternative reading frame peptides elicit T cells with potent antiretrovirus activity
Authors: Yewdell Jonathan W. , Hickman Heather D.
Published: October 2007

CD8+ T cells rapidly recognize virus-infected cells due to the generation of antigenic peptides from defective ribosomal products (DRiPs) that are encoded by standard open reading frames (ORFs). New data now show that alternative reading frame (ARF) DRiPs can also induce robust CD8+ T cell responses. ARF-specific T cells control retroviral replication and select for viral escape in monkeys, providing the most compelling evidence to date for the biological relevance of ARF immunosurveillance.
Dredging for edible cockles (Cerastoderma edule) on intertidal flats: short-term consequences of fisher patch-choice decisions for target and non-target benthic fauna
Authors: Kraan Casper , Piersma Theunis , Dekinga Anne , Koolhaas Anita , van der Meer Jaap
Published: October 2007

Kraan, C., Piersma, T., Dekinga, A., Koolhaas, A. and van der Meer, J., 2007. Dredging for edible cockles (Cerastoderma edule) on intertidal flats: short-term consequences of fisher patch-choice decisions for target and non-target benthic fauna. – ICES Journal of Marine Science, 64. Intertidal flats in the Dutch Wadden Sea are protected by national and international treaties. Still, mechanical dredging for edible cockles Cerastoderma edule was allowed in 74% of 1200 km2 of intertidal flats. Cumulatively, between 1992 and 2001, 19% of the intertidal area was affected by mechanical cockle-dredging at least once. On the basis of a grid of 2650 stations sampled annually, we evaluate the extent to which cockle-dredging from 1998 to 2003 was selective with respect to non-target macrozoobenthic intertidal fauna. In all 4 years that comparisons could be made, to-be-dredged areas contained greater diversity of macrobenthic animals than areas that remained undredged. Targeted cockles were 2.5 times more abundant in areas that were to be dredged shortly, but other species also occurred in higher densities in these areas. Small amphipods and some bivalves occurred less in to-be-dredged areas than elsewhere. In terms of short-term responses to dredging, four non-target species showed a significant decrease in abundance 1 year after dredging. Only Tellina tenuis showed an increase a year after dredging.
High-resolution structure of the photosynthetic Mn4Ca catalyst from X-ray spectroscopy
Authors: Yano Junko , Kern Jan , Pushkar Yulia , Sauer Kenneth , Glatzel Pieter , Bergmann Uwe , Messinger Johannes , Zouni Athina , Yachandra Vittal K
Published: October 2007

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, is described. Issues of X-ray damage, especially at the metal sites in the Mn4Ca cluster, are discussed. The structure of the Mn4Ca catalyst at high resolution, which has so far eluded attempts of determination by X-ray diffraction, X-ray absorption fine structure (EXAFS) and other spectroscopic techniques, has been addressed using polarized EXAFS techniques applied to oriented photosystem II (PSII) membrane preparations and PSII single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS, is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and Kβ emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.
Multifrequency electron spin-echo envelope modulation studies of nitrogen ligation to the manganese cluster of photosystem II
Authors: Yeagle Gregory J , Gilchrist M. Lane , Walker Lee M , Debus Richard J , Britt R. David
Published: October 2007

The CalEPR Center at UC-Davis (
http://brittepr.ucdavis.edu
) is equipped with five research grade electron paramagnetic resonance (EPR) instruments operating at various excitation frequencies between 8 and 130 GHz. Of particular note for this RSC meeting are two pulsed EPR spectrometers working at the intermediate microwave frequencies of 31 and 35 GHz. Previous lower frequency electron spin-echo envelope modulation (ESEEM) studies indicated that histidine nitrogen is electronically coupled to the Mn cluster in the S
2
state of photosystem II (PSII). However, the amplitude and resolution of the spectra were relatively poor at these low frequencies, precluding any in-depth analysis of the electronic structure properties of this closely associated nitrogen nucleus. With the intermediate frequency instruments, we are much closer to the ‘exact cancellation’ limit, which optimizes ESEEM spectra for hyperfine-coupled nuclei such as
14
N and
15
N. Herein, we report the results from ESEEM studies of both
14
N- and
15
N-labelled PSII at these two frequencies. Spectral simulations were constrained by both isotope datasets at both frequencies, with a focus on high-resolution spectral examination of the histidine ligation to the Mn cluster in the S
2
state.
Water oxidation chemistry of photosystem II
Authors: Brudvig Gary W
Published: October 2007

Photosystem II (PSII) uses light energy to split water into protons, electrons and O2. In this reaction, nature has solved the difficult chemical problem of efficient four-electron oxidation of water to yield O2without significant amounts of reactive intermediate species such as superoxide, hydrogen peroxide and hydroxyl radicals. In order to use nature's solution for the design of artificial catalysts that split water, it is important to understand the mechanism of the reaction. The recently published X-ray crystal structures of cyanobacterial PSII complexes provide information on the structure of the Mn and Ca ions, the redox-active tyrosine called YZand the surrounding amino acids that comprise the O2-evolving complex (OEC). The emerging structure of the OEC provides constraints on the different hypothesized mechanisms for O2evolution. The water oxidation mechanism of PSII is discussed in the light of biophysical and computational studies, inorganic chemistry and X-ray crystallographic information.
Investigation of substrate water interactions at the high-affinity Mn site in the photosystem II oxygen-evolving complex
Authors: Singh Sonita , Debus Richard J , Wydrzynski Tom , Hillier Warwick
Published: October 2007

18
O isotope exchange measurements of photosystem II (PSII) in thylakoids from wild-type and mutant
Synechocystis
have been performed to investigate binding of substrate water to the high-affinity Mn
4
site in the oxygen-evolving complex (OEC). The mutants investigated were D1-D170H, a mutation of a direct ligand to the Mn
4
ion, and D1-D61N, a mutation in the second coordination sphere. The substrate water
18
O exchange rates for D61N were found to be 0.16±0.02 s
−1
and 3.03±0.32 s
−1
for the slow and fast phases of exchange, respectively, compared with 0.47±0.04 s
−1
and 19.7±1.3 s
−1
for the wild-type. The D1-D170H rates were found to be 0.70±0.16 s
−1
and 24.4±4.6 s
−1
and thus are almost within the error limits for the wild-type rates. The results from the D1-D170H mutant indicate that the high-affinity Mn
4
site does not directly bind to the substrate water molecule in slow exchange, but the binding of non-substrate water to this Mn ion cannot be excluded. The results from the D61N mutation show an interaction with both substrate water molecules, which could be an indication that D61 is involved in a hydrogen bonding network with the substrate water. Our results provide limitations as to where the two substrate water molecules bind in the OEC of PSII.
Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn
4
Ca core
Authors: Bartlett John E , Baranov Sergei V , Ananyev Gennady M , Dismukes G. Charles
Published: October 2007

Perturbation of the catalytic inorganic core (Mn
4
Ca
1
O

x

Cl

y

) of the photosystem II-water-oxidizing complex (PSII-WOC) isolated from spinach is examined by substitution of Ca
2+
with cadmium(II) during core assembly. Cd
2+
inhibits the yield of reconstitution of O
2
-evolution activity, called photoactivation, starting from the free inorganic cofactors and the cofactor-depleted apo-WOC-PSII complex. Ca
2+
affinity increases following photooxidation of the first Mn
2+
to Mn
3+
bound to the ‘high-affinity’ site. Ca
2+
binding occurs in the dark and is the slowest overall step of photoactivation (IM
1
→IM
1
*
step). Cd
2+
competitively blocks the binding of Ca
2+
to its functional site with 10- to 30-fold higher affinity, but does not influence the binding of Mn
2+
to its high-affinity site. By contrast, even 10-fold higher concentrations of Cd
2+
have no effect on O
2
-evolution activity in intact PSII-WOC. Paradoxically, Cd
2+
both inhibits photoactivation yield, while accelerating the rate of photoassembly of active centres 10-fold relative to Ca
2+
. Cd
2+
increases the kinetic stability of the photooxidized Mn
3+
assembly intermediate(s) by twofold (mean lifetime for dark decay). The rate data provide evidence that Cd
2+
binding following photooxidation of the first Mn
3+
, IM
1
→IM
1
*
,
causes three outcomes: (i) a longer intermediate lifetime that slows IM
1
decay to IM
0
by charge recombination, (ii) 10-fold higher probability of attaining the degrees of freedom (either or both cofactor and protein d.f.) needed to bind and photooxidize the remaining 3 Mn
2+
that form the functional cluster, and (iii) increased lability of Cd
2+
following Mn
4
cluster assembly results in (re)exchange of Cd
2+
by Ca
2+
which restores active O
2
-evolving centres. Prior EPR spectroscopic data provide evidence for an oxo-bridged assembly intermediate, Mn
3+
(μ-O
2−
)Ca
2+
, for IM
1
*
. We postulate an analogous inhibited intermediate with Cd
2+
replacing Ca
2+
.
Using small molecule complexes to elucidate features of photosynthetic water oxidation
Authors: Meelich Kristof , Zaleski Curtis M , Pecoraro Vincent L
Published: October 2007

The molecular oxygen produced in photosynthesis is generated via water oxidation at a manganese–calcium cluster called the oxygen-evolving complex (OEC). While studies in biophysics, biochemistry, and structural and molecular biology are well known to provide deeper insight into the structure and workings of this system, it is often less appreciated that biomimetic modelling provides the foundation for interpreting photosynthetic reactions. The synthesis and characterization of small model complexes, which either mimic structural features of the OEC or are capable of providing insight into the mechanism of O2evolution, have become a vital contributor to this scientific field. Our group has contributed to these findings in recent years through synthesis of model complexes, spectroscopic characterization of these systems and probing the reactivity in the context of water oxidation. In this article we describe how models have made significant contributions ranging from understanding the structure of the water-oxidation centre (e.g. contributions to defining a tetrameric Mn3Ca-cluster with a dangler Mn) to the ability to discriminate between different mechanistic proposals (e.g. showing that the Babcock scheme for water oxidation is unlikely).
Male behaviours towards unplanned pregnancy: experiences of Brazilian low‐income women
Authors: Hoga L. A. K. , Manganiello A.
Published: October 2007

Background:  Lone women are responsible for a quarter of Brazilian families. The unplanned pregnancy, a strong reality for many young poor women in this country, provokes a strong impact on physical, emotional, socio‐economic and family dimensions.

Research questions:  Do personal characteristics determine the behaviours of males towards unplanned pregnancy? Do the associations between the couple’s bond and male behaviours influence attitudes towards unplanned pregnancy?

Methods:  This descriptive study was carried out in a low‐income community in the City of São Paulo, Brazil. A structured form was composed to obtain data from 100 women who have lived out the unplanned pregnancy experience.

Findings:  Personal characteristics do not appear to determine male behaviours towards unplanned pregnancy. There was a statistically significant difference among men in different types of bonding relationship (married, cohabiting, dating, without bonding) with regard to the following behaviours: attention given during pregnancy; changes to the type of bond between partners; civil registration of the child by the father; financial support provided by the father and contact with the child.

Conclusions:  Bonding and correlated topics are essential in sexual and reproductive healthcare education and promotion.

Limitations:  Population sampling was statistically calculated based on community demographic data and the conclusions refer to the estimated parameters of men’s behaviours according to women’s experiences.
Knowledge of, and attitudes to, acquired immune deficiency syndrome (AIDS) among traditional birth attendants (TBAs) in rural communities in Cross River State, Nigeria
Authors: Bassey E. B. , Elemuwa C. O. , Anukam K. C.
Published: October 2007

Aim:  To survey knowledge of, and attitudes to, HIV/AIDS held by traditional birth attendants (TBAs) in rural communities in Cross River State, Nigeria.

Background:  As the HIV/AIDS epidemic continues to spread, undermining development, reversing health gains and exacerbating poverty, TBAs in rural communities in Cross River State, Nigeria are still less informed about this dreadful disease.

Methods:  A survey consisting of structured questionnaires was used with 140 randomly selected TBAs to assess their knowledge of HIV/AIDS, source of information on HIV and protective practices.

Findings:  Results revealed that 62 (44.3%) of the TBAs had no formal education. Forty‐four (31.4%) had primary education, while 19 (13.6%) had secondary education. On knowledge of HIV and sources of information, 49 (35.0%) of respondents reported knowing what HIV means. While 26.4% indicated that they received information about HIV from the government health centres, 23.6% had no information about the disease. There was a great disparity between male (73.7%) and female (28.9%) respondents on knowledge about HIV. On the use of protective safety procedures during delivery, 61 (43.6%) used sterilized blades, while 10.7% admitted wearing protective clothes and gloves. Only three (2.1%) of the respondents said that they were aware of the HIV status of their clients prior to delivery.

Conclusions:  This survey has demonstrated that few TBAs in the communities studied in Cross River State are informed about HIV/AIDS, and this has revealed the urgency of starting a programme specifically designed for TBAs in rural communities towards a massive educational campaign on HIV/AIDS.
Mitigating the plight of HIV‐infected and ‐affected nurses in Zambia
Authors: Vitols M.P. , Du Plessis E. , Ng’andu O.
Published: October 2007

Aim:  This article responds to the challenge to nurses to ensue and write about successful HIV‐related research projects. The article describes the highly valuable ‘Caring for the Caregivers’ project in Zambia, highlighting the development of the project, valuable lessons learnt and further developments. The article serves as a valuable guideline for nurses and health professionals from other disciplines in developing similar projects.

Background:  In a sub‐Saharan country hard hit by HIV/AIDS, nurses and midwives desperately need support. The Zambian Nurses’ Association and the Norwegian Nurses’ Organisation partnered to mitigate the plight of infected and affected nurses in Zambia in a sustainable manner.

Focus of this article:  This article highlights the successes of this partnership, as well as valuable lessons learnt. It reflects on a needs assessment survey carried out to identify the needs of nurses in caring for AIDS patients, and describes the ensuing recommendations and implementation of the ‘Caring for the Caregivers’ project, focusing on training, local support groups and monitoring. Further developments are mentioned briefly and the relevance of such a partnership and ensuing project for the discipline of nursing is also commented on.